CA2355986C

CA2355986C - Heater-installed grip for vehicle, control device for heater installed in vehicle grip, and electrical connection structure for heater unit for grip in vehicle

Info

Publication number: CA2355986C
Application number: CA002355986A
Authority: CA
Inventors: Toru Ogata; Nobuhiko Muramatsu; Shinji Teraoka; Yasuo Ohishi
Original assignee: Koito Manufacturing Co Ltd
Current assignee: Honda Motor Co Ltd
Priority date: 1996-08-29
Filing date: 1997-08-27
Publication date: 2005-06-28
Anticipated expiration: 2017-08-27
Also published as: CA2355986A1

Abstract

A heater-installed grip for a vehicle includes substantially semi-cylindrical inner pieces (33 1, 33 2) of a synthetic resin which have a planar heater (34L, 34R; 174L, 174R;
184) wound around an outer periphery thereof and which are integrally embedded in a cylindrical grip body (35) made of a rubber assembled to a pipe-shaped steering handlebar (26) or a throttle pipe (79). In this heater-installed grip, a circumferentially central portion of each of the inner pieces (33 1, 33 2) is formed at a large wall thickness, as compared with circumferentially opposite ends thereof. Thus, the assemblability of the grip body (35) to the pipe-shaped steering handlebar (26) or the throttle pipe (79) is enhanced, while ensuring a die-clamping strength in a process for forming the grip body (35).

Description

70488-120D _-HEATER-INSTALLED GRIP FOR VEHICLE, CONTROL DEVICE FOR HEATER
INSTALLED IN VEHICLE GRIP, AND ELECTRICAL CONNECTION STRUCTURE
FOR HEATER UNIT FOR GRIP IN VEHICLE
This is a division of our co-pending Canadian Patent Application No. 2,235,968 dated 27 August 1997.
TECHNICAL FIELD
The present invention relates to a heater-installed grip for a vehicle such as a motorcycle, a snowmobile, a buggy vehicle and the like, a control device for a heater installed in the vehicle grip, and an electrical connection structure for a heater unit for the grip.
BACKGROUND ART
Such grips are conventionally known, for example, from Japanese Utility Model Publication No. 7-48463 and the like. As shown in Figs. 37 and 38, the grip is of a structure in which a flexible printed wiring heater circuit 190 (which will be referred to as an FPC heater hereinafter) is integrally embedded, in a mode in which it has been wound around a semi-cylindrical inner piece 33' made of a synthetic resin, in a cylindrical grip body 35' made of a rubber and capable of being fitted into a pipe-shaped steering handlebar 26. A feeder cord (not shown) is soldered to a lead portion 190a of the FPC
heater 190 led out of the grip body 35'.
In producing the grip body 35', the following steps are sequentially conducted as shown in Fig. 39: a step of assembling

2 the inner piece 33' having the FPC heater 190 wound therearound to a core 191; a step of winding a sheet 192 of a raw rubber around the FPC heater 190;a step of bringing dies 193 and 194 in a state in which the resulting sheet has been accommodated therein, into close contact with each other to clamp them; a step of pouring a molten rubber into the dies 193 and 194 at a point when the temperature has reached a level at which the raw rubber sheet 192 within the dies 193 and 194 is molten, thereby forming the grip body 35' ; and a step of removing the formed grip body 35' out of the dies 193 and 194 at a point when the rubber within the dies 193 and 194 has been vulcanized, and then cooling the removed grip body 35' by leaving it to stand for a predetermined time.
In the above heater-installed grip, however, the inner piece 33' made of the synthetic resin is formed at a circumferentially constantand relatively large wallthickness.
For this reason, the flexibility of the grip body 35' is small, and in press-fitting the steering handlebar 26 into the grip body.35', the grip body 35' cannot follow the movement of the steering handlebar 26 which is press-fitted and hence, it is difficult to press-fit the steering handlebar 26 into the grip body 35' . If the steering handlebar 26 is forcibly press-fitted into the grip body 35', there is a possibility that the inner piece 33' may be cracked, resulting in a very poor assemblability of the grip body 35' to the steering handlebar 26.

3 Therefore, if the inner piece 33' is formed at a relatively small wall thickness, the flexibility of the grip body 35' is increased, whereby the assemblability of the grip body 35' to the steering handlebar 26 is enhanced and the possibility of cracking of the inner piece 33' is eliminated.
However, during clamping of the dies in forming the grip body 35 ' , the inner piece 33 ' may be cracked in some cases , because it cannot withstand the clamping.
The conventional inner piece .33' suffers from the following problem: Since the conventional inner piece 33' is semi-cylindrical, the rubber layer is cooled and shrunk in the course of cooling of the grip body 35' after being removed from the dies 193 and 194 , especially, a rubber layer region s~ opposed to the inner piece 33' is shrunk, and the circumferentially opposite ends ~, ~ of the inner piece 33' are deformed in a direction to approach each other by such shrinking force and as a result, the grip body 36' is warped.
An electric power for heating a heater in such a heater-installed grip by a heater is supplied from a battery mounted on a vehicle. The capacitor of the battery is limited and hence, it is desirable that the grip is effectively warmed by an electric power as small as possible . In the conventional heater-installed grip, however, the FPC heater is disposed in a uniformly dispersed manner in the grip body and is of a construction to uniformly warm the entire grip. Therefore, to warm the grip up to a comfort temperature, there is a possibility

4 that the amount of power consumed may be increased to produce the running-out of the battery. If the amount of power consumed is suppressed, the rising of the temperature of the grip is insufficient.
The conventional heater control device is of an arrangement in which as shown in Fig . 40 , heaters 190 and 1908 mounted respectively in the left and right handlebar grips of the steering handlebar in the motorcycle are connected in series; a switch 195 is mounted between one of the heaters 190L
and the battery 90, and a variable resistor 196 is connected in series to the other heater 1908, so that the electric current flowing through the heaters 190 and 1908 is regulated and the power consumed in the heaters 190L and 1908 is controlled by varying the resistance value of the variable resistor 196, thereby maintaining the handlebar grips at a suitable temperature.
However, there is a problem that the power consumed in the variable resistor 196 is relatively large, and the battery 90 cannot be utilized efficiently. Especially, in a case of the grip heater mounted in the handlebar in the motorcycle or the like , the power consumed in the heaters is large , because it is in direct contact with the open air, and the power consumed in the variable resistor is increased because of a large range of variation in temperature of the open air. This makes it difficult to utilize the battery efficiently.
The warming of the grip by the heaters installed in the grip for the vehicle is attended on the traveling of the vehicle.
To have a preference of the traveling of the vehicle, it is required that the supplying of the power from the battery to the heaters should be stopped when the power source voltage of the battery has been dropped down to a value equal to or lower than a voltage required at a minimum for driving a starter motor.
Even in the above conventional heater-installed grip, the control of the supplying of the power to the heater is carried out in the above manner. However, if the timing to stop the supplying of the power to the heaters is established so that the supplying of the power is stopped at a voltage threshold value larger than required to reliably ensure a minimum power source voltage required in the battery, a state in which the grip can be warmed by the heaters is extremely limited. If the voltage threshold value is too small, the supplying of the power to the heaters is conducted even if the voltage becomes equal to or smaller than the minimum power source voltage required in the battery due to an error of detection of the voltage or a drop of the voltage from the battery to a detected portion, whereby it may be difficult to start the vehicle. Therefore, it is desirable that the voltage threshold value for determining the timing for stopping the supplying of the power to the heaters is set at a necessary minimum value in consideration of the voltage detection error and the voltage drop.
If the supplying of the power to the heaters is stopped, the power source voltage of the battery is slightly risen . If the supplying of the power to the heaters is controlled in an ON/OFF manner at a constant voltage threshold value, turning-ON/OFF of the supplying of the power to the heater is frequently repeated to produce a control hunching. Therefore, the grip cannot be stably warmed, and a good warm-feeling is not obtained.
In mounting of the grip heater unit comprised of a heater installed in a grip of a steering handlebar and a control device for controlling the heater to a vehicle such as a motorcycle, if the grip heater unit is assembled exclusively for the vehicle as manufactured, then a plus-side connecting wire is connected directly ,to a plus side of the battery, and minus-side connecting wire is connected directly to a minus side of the battery. In this case, there is particularly not a problem arisen. However, if the grip heater unit is applied to a commercially available vehicle, or the application thereof to a large number of types of vehicles is considered, it is desirable that the connection of the plus-side connecting wire and the minus-side connecting wire extended from the grip heater unit to the plus side and the minus side of the battery can be easily performed for any type of the vehicles . Moreover, the heater is installed in the grip of the turnable steering handlebar, and it is necessary to avoid the arising of problems in the reliability and the durability of the connection structure as a result of twisting of the connecting wires due to the connection of the plus-side and minus-side connecting .. 7 -vrires .
SU1~IARY OF THE INVENTION
=t is an ob~eat of the present iav~eation to provides a control device for a heater installed ire a grip for a vehicles, wherein a battery can be efficiently utilised.
=t is a further ob~eot of the present invention to provide a control daviae for a heater installed is a grip fox' a vehicle, ~lhereia~the zunaiag-out of the battery oaa be xeliabiy prevented, and the grip oan be stabiy warmed, thereby pravidiag a good waxen-feeling.
Us 4,838,113 diealosea a oontrol device for a heater installed in a grip for a vehicles, comprising a switching mesas for ODT/OFF-controlling a power supplied from a battery to a heater installed is a grip mounted on a steering handlebar, cad a drivit~-signal outputting maau~a for outputting a driving signal for turning the switohing maaaa o~ir.
The present invention is characterised over US
4,838,113 is that said control devise further includes a battery voltage monitoring means which ~.s operable to provides a state to prohibit the outputting of the drive signal from said driving-siq~ual outputting means, whey a voltage corresponding to a power a~ourae voltage outputted froua said battery is smaller than a f ~.r~t voltege threshold value, arid to prov3.de a stars to per~ait the outputting of the drivfag signal front the driving-signal outputting taeaas, when the voltage corresponding to said power aourae voltage is equal to or larger tlxaa a second voltage threshold vale set higher than said first voltage threshold value by a _ g _ predetermined value or more, said first voltage threshold value being set as being, (VM - aVl + pV2) , wherein VM
represents a necessary minimum power source voltage required in said battery; OV1 represents a decrement of voltage dropped from said battery to said battery voltage monitoring means;
and OV2 represents a maximum voltage detection error on the plus side presumed in said battery voltage monitoring means.
With the invention claimed, the voltage threshold value (the first voltage threshold value) serving to stop the supplying of the power to the heater is determined at an extremely small level in consideration of the decrement of voltage dropped from the battery to the power source voltage monitoring means and the voltage detection error presumed in the power source voltage monitoring means. Thus, even if the voltage threshold value becomes equal to or lower than the minimum power source voltage required in the battery, chances to be able to warm the grip by the heater can be increased to the utmost, while avoiding the supplying of the power to the heater. In addition, by permitting the supplying of the power from the battery to the heater at the second voltage threshold value higher than the first voltage threshold value by the predetermined value or more, the switching-ON and OFF of the supplying of the power to the heater can be prevented from being frequently repeated, thereby stably warming the grip.
The control device preferably further comprises a periodic voltage generating means for generating a periodic voltage whose value is periodically varied, a comparative voltage outputting means for outputting a - g -predeter~niaed comparative voltage depending upon a te~n~aratztra regulating operation far the hsatet, a rectangular-wow signal outputting mea~xe for outputting a reatangulax-wave signsl having a duty ratio depending upon said te~erature regulating apexatioa by comparing the periodic voltage outputted from said periodic voltage generating tseatu; with the campatatiw vo~.tage outputted from said cos~rarative voltage outputtiriy menus, wherein said switching mesas is for p1~/OFF-aoutroiii~ng the power supplied from the battery to said heater in re~rponse to the reatsagular-wave signal outputted from said xectaagular-wave signal outputting means.
Witb these preferred features of the inventiox~, there is no wasteful consumption of the power at the ve~xieb7.e resistor, as compared with the conventional device in which the resiatauGe valve of the variable resistor connected in ~3exies to the heatet~ is varied.
Therefore, the battery rsan be efficiently utilised.
=t is a further object of the present invet~tion at least in its preferred embodimeata to provide a heater-installed grip for a vehicle, wherein the asssmblribility of a grip body to a pipe-shaped steering handlebar ox a throttle pipe is enhanced, while eppuring the clamping strength at a step of forming the grip body, by varying the plate thiokaess of an inner piece in e, cirautaferential direction thereof.
Preferabljr therefore, a system for a vehicle having a heater-ixiata.l~.ed grip is provided, the eysteta cotqprising a grip having a heater cad a control device aaCording to the iaverit3.on, said grip further adt~ris3x~g eubsta~atially semi-cylindrical eases pieces of a synthetic resin ~rhich bave a plaasar beater v~~ouad aromsd as outer periphery thereof and which ire integrally embedded is a cylixidrical grip body of a rubber assewbied to a pipe-shaped steerixtg baudlebar or a throttle pipe, wheraia a circumferentially central portion of each of the inner pisses is formed w~.th a wall thiclCaese larger thaw those of oiroutnfereatially opposite ends thereof.
preferably, the system comprises subst:ntiallx same-cylindrical saner pieces of a synthetio resist which haven a planar heater wound around as outer periphery tbex~eof and which are integrally e~abedded in a cylindrical grip body of a rubber assembled to a pipa-shaped steering handlebar or a throttle pipo, 'dhereisx grooves arcuate ih arose section, into which a kltea.
rubber flows in the formation of the grip body, are defined is saner peripheral surfaces of the saner piaoes, preferably the system ooropriees substantially semi-oylindriaal inner pieoes of a Synthetic resin which have a planar heater wound around au outer periphery thereof and which are integrally embedded j.u ~t cylindrica~7. grip body of a rubber asseanbled to a pipe-shaped steering haadlabar or a throttle pipe, t~hereia an axially extending projection is forced at a airvumfereutially cent~tal portion of as inner surface of each of said saner Qieces.
pith the Brat teatute, by the fact that the cirQUmferentislly opposite each of the saner pieee havQ
a relat~.vely small wall thickness, the flexibility of the saner piece and thus of the grip body is ehhaticed, so that tha grip body aatt follow the movement o:~ the steeritLg b~aadlebar or the throttle pips t~ltirh is pross-~itted. Moreover, is the alampin~g of dial, t~ large external force acts os the eirCtunferentiaily aeatxal portion of the inner pisae, but by the fact that the ciroumferenti$lly central portion of the inner piece is formed at the relatively large wall thiakaesp, the inner piece aanaot be deformed.
atith the second feature, by the f~tet that the groove is defined is the inner peripheral surface of the inner piece, the fle:ibility of the latter piece cad thus of the grip body is sahaaaed, eo that the grip body can follow the tnovemeat of the steering handlebar or the throttle pipe which is press-fitted. Moreover, the rigidity of a portion is the viaiaity of the groove can be enhanced by forming the section of the groovy ~xtto as arcuste shape, thereby eahaaC3.ag the rigidity of the entire ~aaer piece. Therefore, even if a large external force acts on the oirGumfereatially central portion o!
the inner piece is the clamping of dies, the inner piece cannot ba dsgormed.
with the third feature, by the fact that the' a:iaily eacteading project~,~aa is fornwd at the circumfereatialxy central portion of the inner surface o! the inner piece, the cixcumfereatially central portion of the inner piece is formed at a large wail thiclcaees, 2~s co~ared with the circumfaxeatially .
opposite ends. and the oiraunfexeatially opposite ends.
of the inabr pieoe axe formed at a relatively small mall thickaeas. Thus, the fhdbiZity of the iaa~er piece and thuat of Ghe grip body is eaharired, so that the grip body - lZ
can follow the movement of the steering handlebar or the throttle pipe which is prsss~fitted. 8ven it a large esterx~al force acts on the c~4rauanferentiaily eentrai portion of the inner piece in the cling of diva, the inner piece Cannot be deformed since the aircumferentially central portion of the inner piece is foraged at a relatively large stall thic~ss.
It ie a still further object of the present invention at least in its preferred embodiments to prorride a heater-installed grip for a vehicle, wherein the rigidity and strength of an inner piece are enhanced, so that a grip body cannot be deformed after being foro~ed.
The present inventioxt therefore preferably provides a system for a vehicle having a heater-installed grip the system cotsprisitig a grip having a heater and a control device according to the invention, and further comprising a substantially senni-cyliadrioal annex piece of a synthetic resin which has a planar heater wound arQUx~.d as autex periphery thereof and wbioh is integrally embedded in a cylindrical grip body of a rubber aBaembled to a pipe-shaped atsering handlebar or a throttle pipe, wherein said inner piece ie integrally provided, at axially predeteraniaed locations thexean, with annular portionre Which are intended to prevent the deformation of the inner pieces attendant on the shrinkage of a rubber layer after for~aation of the grip body. and each of which fuaationg as a guide for insertion of the steering handlebar or the throttle pipe.
A shriaki.ug forc8 produced in the cooling and solidification of the rubber layer acts ou the grip body reproved from the dies, thereby shrinking cad deforaling th: rubber layer in the ciraumfereatial and axial direction~, particularly in a rubber layer region opposed to the inner piece, and deforming the ciroumferentially opposite ends of the inner pieco eo that the opposite ends are adjt~ceat to each other.
8owaver, according to the fourth feature, the annular portion integrally included in the inner piece receives the shrinking force acting on the rubber layer.
Therefore, it is possible to provide the inner pisee with a rigidity and strength es~,ough to ~rsveat the deformation of they inner piece, and it 3s possible to prevent the produced grip body from warping to reduce the rate of generation of a defeativ~e product.
Moreover, by the fact that the ~aular portion is provided at a portion of the axially predetermined locatiost of the inner piece, the flexibility of the grip body at the time when tha steering handlebar or the throttle pipe is press-fitted into the gzip body cannot be remarkably injured at the atinulax portion.
Furthermore, since the annular portion furictioas as a guide for insertion of the steering handlebar or the throttle pipe, the aseemblability of the grip body to the steering handlebar or the throttle pipe can be enhanced. It is another object of the present invention at least iu its preferred embodiment$ to provide a heater-installed grip for a vehie~,e, wherein the grip can be effectively warmed with a small amount of power' oonsumed.
The invention preferably provide~ a system for a vehiala having a heater-installed gr~.p, the system comprising a grip havinrg a heater sad a aotitrol devise according to the invention and further congrrisiag a heat geaeratirag elameat integrally embedded in substantially as entire periphery of a grip body made of a rubber, wherein said heat generating elecnerit ie disposed is a dispere~ed manlier is the grip body 3.a such a manner thst the density of the heat generating element dispersed at a front portion of said grip body is the direction of movement of the vehicle ie higher than that at a reax portion o! said grip body.
The ~systeo4 preferably cot~prlsee a heat generating sletnent integxally embedded in eubataatially :a entire periphery of a grip body made of a rubbex, wherein said heat generating element is disposed is a dispersed manner is said grip body in such a manner that the density of sa3.d heat gaaeratiag element dispersed at as end portior~ of said grip body located oa an inner side when assetubled on said vehicle, is higher than that at an opposite end portion of said grip body located oa an outer side when assembled on said vehicle.
fhe system preferably comprises a heat geaer~ttiag element integrally embedded-in substantially half of a periphery of a grip body made of a rubber, whexein Staid heat generating element ie disposed in the grip body at a portiox~ located at the front of said grip body in a dlraction of movement of the veh~,cle whau aasemblad oa the vehicle.
fhe system preferably comprises a heat generating element integrally embedded is substantially half of a periphery in a grip body made of a rubber, wherein said - 14a -heat generating eleaa~snt ie disposed in a dispersed Manner ix~ said gr~.p body in such a manner that the density of said heat generating element dispersed at as end portion of said grip body located oa as inner aide when assembled on the vehicle i8 higher than that at as opposite end portion o! said grip body loeatad on as .outer aids when assembled oa the vehicle.
The front portion of the grip body iti the direetioa of movement of the vehicle is a portion touched by fingertips of a hand grasping the grip. Hy the fast that the daasity of heat generating eleme~at dispersed at such portion is higher than that at the rear portion of the grip body, or the heat generating element is disposed only at the front port3ot~ of the grip body, the fingertips sensitively feeling the sold eau be effectively warsaad, thereby providing as excellent v~rarm-feeliag~With a relatively reduced amount of power aonsu~ued. particularly, the att~unt of power eonsmaned can be rslativaly reduced ale waxming the entire grip by the heat generating elemQat dispersed over the entire periphery of the gxip, thereby providing as e~ccelleat warm-feeling. to additioxz, the inner sad portion of the grip body is a poxtion relatively strongly touahod by a head when grasping the grip, ey the fact that the density of heat generating element dispersed at auCh portion is larger than that at the outer sad portion, ox the heat generntiag element iB disposed only at the inner end portion, a hand osa be effeotively warmed, thereby providing as excellent wat~a-fweliag with a relatively reduced amount of power eoaaumed.
particularly, the amount of power Cotuumed Csa be - 14b -relatively reduoed while warm3ag the vatire grip by the heat generating ele~aeat diaper'sed over the satire periphery of the grip, thereby providing an excellent wart- f eelfug .
=t is a still Further objsat a~ the pxessat inventi.oa, at least is its preferred embodiments, to provide an electrical connection structure for a heater unit for a grip is a vehicle, v~herei=s the heater unit for the grip can be easily mounted to any type of vehicles to provide a general-purpose utilisaatioa of a aonaeetioti, sad the arising of problems is reliability sad durability of the connection structure csa be avoided in the general-,purpose utilization of the connection.
To achieve this object, there is preferably provided a system for a vehicle having a heater-installed grip, the system comprising s. grip having a heater sad a control device according to the iaven~tioa, the system further comprising au electrical connection structure for a heater unit, the heater unit Comprising the $eater anal the control device, the grip baia~
mounted oa a steering hsudl8bar of the vehicle its, use, sad wherein is use plus-side and minus-Bide connecting wires led out of said heater unit for the grip are interruptively connected to a plus wire of one of first and second electric parts of the vehicle and to a minus wire of the other eleotrie part at locations Gear said electric parts which are disposed on said steering handlebar or a member turned is unison with said steering handlebar sad to which a power is supplied from the battery is use.

- 14c -=a an alternative preferred embodiment of the invention, a systeta for a vehicle having a haater-installed grip is provided, the system eoa~priaing a grip having a heater and a control device according to the ~ventioa, the system further comprising an electrical connection atruature for a heatex unit, the heater unit comprising the heater sad the control device, the grip being mounted on a Steering handlebar of the vehicle in use, and wherein in use an earth ware connected to s grounding portion of said battery is coupled to the Steering handlebar or a membex which is turned is unison with the steering handlebar, wherein in use a first coaneatiag wire led out of said heater unit for the grip is interruptively aoaneated between the battery and as electric part of the vehicle at a location near said electric part ovhich is disposed on the steering handlebar or the member turned is ur~isoa with the steering handlebar and to r~hiah an electric power is supplied fxom the battexy in use, and a secoa8 connecting wire led out of said heater unit for the grip is aormeeted in use to said ~teeriug handlebar or said utetnber turned is unison t~ith the eteer~.ng handlebar.
By the fact that the plus-Bide sad minus-Side connecting wires are interruptively aouaected to the plus wire of one of the first and second electric parts axed to the minus wits of the other eleatrio part which are disposed on the steering handlebar or the member tarried is unison with the Steering handlebar, the connectiox~ of thQ heater unit for the grip to the power Source is achieved. Thus, the general-purpose utf.lization of the connection to auy type of various - 14d -vehicles can be aahievsd, while avoiding the oavurreaoa of the ntis-operation of the elsatx~ic parts eves it the heater is operated. Moreover, by the fact that the electric parts are disposed on the steering handlebar or the member turned in uaievn with the steering handlsbax, wiring portions aonaectad to the eisetric pa~tta are wired so that they are not twisted even due to the turning of the steering handlebar. Thus, the aonaection structure interruptively connected tv such wiri.ag portions in the vicinity of the steering handlebar offers no problem in durability and reliability thereof.
In the alternative preferred embodiment, ae the first connecting wire is interruptively connected between the power source and the electric part disposed on the steering handlebar or the member turned in unison with the steering handlebar, and the second Connecting wire is Gorinected to the steering handlebar or the member turned in unison with the steering handlebar to which the earth wire is connected. Therefore, the conneatioa of the heater unit fvr the grip to the power source is atChieved sad thus, the general-purpose utilisation of the connection to any. type of various vehicles can be achieved, while avoiding the occurraace of the mis-operation of the electric parts even if the heater is operated. Moreover, since the eleetria part ie disposed on the steering handlebar or the member operated in unison with the eteexing handlebar, airing portions connected to the electric part are wired so that they are not twisted even due to the turning of the steering handlebar. Thus, the coaaectioa structure connected to such wiring portions in the vieit~ity of the - 14e -steerix~ handlebar offers no problem fa durability cad reliability thereof, =n additiotx, the ssoo~id oorineat~
wire Conaseted to the steering haadlebe~r or the a:em~r tutt=ed 3.n unison with the steering handlebar to wrhiCh the earth wire is connected, cannot also be twisted eves due to the turning of the steexiag haadleber.
prefet~red embodiments of the invention will now beg deporibed, by way of exatapla oily, and with r~fereace to the acvompanyixsg drawings iu Which:
Figs. 1 to ai illustrate a first embodiment, wherein Fig. i is a perspective view of a front portion of a tnotoreycle;
Fig. z is a perspeGtivs view of a left grip as viewed from the front thereof;
Fig. 3 ie a partially-omitted perspective view of the~left grip itx a state in which it has been turned through 90 degree from a state shown is dig.
Fig. 4 ie a longitudit~al sectional view of the left grip with a steering handlebar omitted;
Fig. 5 is a sectional view taken along a line 5-5 is Fig. 4;
Fig. G is a sectional view taken along a luxe 6-6 is 81g. 4.
Fig. 7 is as exploded perspective view of as inner piece assembly and a heater;
Fig. 8 is a partially-omitted perspective view of the left grip as viewed from the rear thereof;

Fig.9 is a front view of the inner piece assembly;
Fig.lO is an illustration for explaining the flow of a molten resin in forming a second inner piece;
Fig. 11 is an illustration for explaining a step of forming a grip body;
Fig. l2 is an enlarged perspective view of a feeder cord;
Fig. l3 is a sectional view similar to Fig.S, but showing a right grip;
Fig.l4 is a partially enlarged view of a portion of Fig. l3;
Fig.l5 is an electric circuit diagram showing the arrangement of a heater unit for a grip;
Fig. l6 is a diagram showing the timing for outputting a periodic voltage and a driving signal;
Fig. l7 is a diagram showing the timing for outputting a proportional voltage and the driving signal;
Fig. l8 is a front view of a control box;
Fig.l9 is a sectional view taken along a line 19-19 in Fig. l8;
Fig.20 is a circuit diagram showing a structure of connection between a heater unit for a grip and a stop switch - as well as left and right front winkers;
Fig. 21 is a perspective view showing a wiring state around a front fork;
Fig.22 is a circuit diagram similar to Fig.20, but according to a second embodiment;

Figs.23 to 30 illustrate a third embodiment, wherein Fig. 23 is a perspective view of a left grip as viewed from the front thereof;
Fig.24 is a sectional view of the left grip grasped by a left hand, taken along a line 24-24 in Fig.23;
Fig.25 is a sectional view taken along a line 25-25 in Fig.23;
Fig.26 is a longitudinal sectional side view of the left grip, ~ with only a grip body being omitted, taken along a line 26-26 in Fig.25;
Fig.27 is a sectional view taken along a line 27-27 in Fig.25;
Fig.28 is an exploded perspective view of an inner piece assembly;
Fig.29 is a plan view of a heater with an overlying film being omitted;
Fig.30 is a sectional view similar to Fig.24, but showing a right grip grasped by a right hand;
Fig.31 is a plan view similar to Fig.29, but showing a heater according to a fourth embodiment;
Figs.32 and 33 illustrate a fifth embodiment, Fig.32 .. being a partially cross-sectional view of a grip, and Fig.33 being a graph illustrating variations in temperature of the grip surface with the lapse of time;
Figs.34 to 36 illustrate a sixth embodiment, wherein Fig . 34 is a plan view of a right grip in a buggy vehicle ;

70488-120D w Fig.35 is a sectional view taken along a line 35-35 in Fig.34;
Fig.36 is a plan view similar to Fig.34, but with the grip being removed from a steering handlebar;
Fig.37 is a longitudinal sectional view of a conventional heater-installed grip;
Fig.38 is a sectional view taken along a line 38-38 in Fig.37;
Fig.39 is a sectional view for explaining a die clamping step in the formation of a grip body; and Fig.40 is a circuit diagram of a conventional heater control device.
BEST MODE FOR CARRYING OUT THE INVENTION
A first embodiment of the present invention will now be described with reference to Figs.l to 21. Referring first to Fig.l, a front fork 21 for suspending the front wheel W is rotatably carried at a front end of a vehicle body frame of a motorcycle. A head lamp 22 and left and right front winker lamps 23~, and 23R are mounted at a longitudinally intermediate portion of the front fork 21 , and a speedometer 24 and a tachometer 25 '- are mounted at an upper end of the front fork 21.
A laterally extending pipe-shaped steering handlebar 26 is mounted at the upper end of the front fork 21 to steer the front wheel W. A left grip 27L1 and a clutch lever 28 operated by a le.~t hand grasping the left grip 271 are disposed at a left end of the steering handlebar 26, and a right grip 2781 and a brake lever 29 operated by a right hand grasping the right grip 2781 are disposed at a right end of the steering handlebar 26.
Referring to Figs.2 to 9, the left grip 27L1 is formed into a cylindrical shape, so that the steering handlebar 26 in the motorcycle is press-fitted into the left grip 271 to fix the left grip 271,1 at the left end of the steering handlebar 26. . The left grip 271 has an outward protruding flange portion 32 provided at an inner end in a widthwise direction of the motorcycle, i.e., at an inner end thereof. An opening at an outer end of the left grip 27L1 is occluded by a cap (not shown) detachably mounted therein.
The left grip 271,1 is comprised of an inner piece assembly 33 formed cylindrically and a sheet-shaped heater 341, wound around the substantially entire periphery of an outer surface of the inner piece assembly 33 , the assembly 33 and the heater 34~ being integrally embedded into a grip body 35 made of a rubber.
The inner piece assembly 33 is formed into a cylindrical shape with first and second inner pieces 331 and 332 abutted ... against each other. Each of the inner piece's 331 and 332 is formed, for example, by an injection molding from a synthetic resin, and it is desirable that each of the inner pieces 331 and 332 is formed from a glass fiber-incorporated polybutylene terephthalate resin, a glass fiber-incorporated polyphenylene 70488-120D w sulfide resin or the like, because each of these resins has an excellent heat resistance and also has a high strength due to a glass fiber dispersed therein.
Each of the inner pieces 331 and 332 is formed by the injection molding. In forming the second inner piece 332 in the injection molding, a molten resin is injected into a metal mold in such a manner that a gate G1 is located on an outer peripheral surface of the second inner piece 332 in the vicinity of one corner- thereof , as shown in Fig. 10 . Thus , the flows of the molten resin and the glass fiber are turned in a lengthwise direction (an axial direction) of the second inner piece 332, and as a result, the formed second inner piece 332 has an increased strength. The first inner piece 331 is also formed by the injection molding, as is the second inner piece 332, whereby the first inner piece 331 has an increased strength.
The first inner piece 331 is formed semi-cylindrically so as to basically have a substantially semi-circular shape in cross section, so that when the first inner piece 331 has been mounted in the steering handlebar 26, an annular portion 36 located at axially one end inner in the widthwise direction of the motorcycle, i.e., at an inner end thereof and an annular .. portion 37 located at the axially other end outer in the widthwise direction, i.e. , at an outer end thereof are opposed to each other at lengthwise opposite ends of the first inner piece 331. The second inner piece 332 is formed semi-cylindrically so as to have a substantially semi-circular shape in cross section, so that its circumferentially opposite ends are abutted against circumferentially opposite ends of the first inner piece 331 between both the annular portions 36 and 37.
Moreover, the second inner piece 33z is provided, at - circumferentially central portions at its lengthwise opposite ends, with engage projections 38 and 39 which protrude on opposite sides in the lengthwise direction of the second inner piece 33z. The inner pieces 331 and 33z are abutted against each other in such a manner that the engage projections 38 and 39 are brought into engage recess 40 and 41 defined in the annular portions 36 and 37 of the first inner piece 331, whereby both the inner pieces 331 and 33z are integrally assembled as the cylindrical inner piece assembly 33 . Thus . the i nnar .,; ~,....
assembly 33 comprised of the inner pieces 331 and 332 has an increased assembly rigidity, and a disadvantage that the grip body 35 made of the rubber is deformed due to the shrinkage of the rubber layer after being removed from the metal mold, cannot be produced.
More specifically, in forming the grip body 35, as shown in Fig.ll, a primer and an adhesive are applied to inner and outer peripheral surfaces of the cylindrical inner piece assembly 33 comprised of the inner pieces 331 and 332, and the primer and the adhesive are also applied to opposite surfaces of the heater 34~. The inner piece assembly 33 with the heater 34L and a crude rubber sheet (not shown) covering the heater 34~ being wound therearound is assembled to a core die 82 and accommodated between an upper die ( not shown ) and a lower die 83. In this case, a cord 72 extends from the inner piece assembly 33, and each of the upper die and the lower die 83 is provided with an insertion bore 84 for drawing out the cord 72 to the outside. _ Then, in a state in which the upper die and the lower die 83 have been brought into close contact with each other and thus clamped; a molten rubber is~~poured and filled through a gate GZ into the upper die and the lower die 83 heated up to a melting temperature of the rubber. During this time, the molten rubber from the gate GZ pushes the annular portion 36 of the inner piece assembly 33 against the upper die and the lower die 83.
Therefore, the position of the inner piece assembly 33 within the upper die and the lower die 83 is stabilized, whereby the filling of the molten rubber can be performed smoothly. At a time point when the rubber has been vulcanized after a lapse of a predetermined time from the filling of the molten rubber, the upper die and the lower die 83 are opened, and the formed grip body 35 is removed and cooled. The flange portion 32 is also formed as a portion of the grip body 35 made of the rubber .
In the cooling course during such formation of the grip body 35, the shrinking force produced in the rubber layer of the grip body 35 acts in the circumferential and axial directions of the inner pieces 331 and 33z. However, since the annular,portions 36 and 37 are provided at the axially opposite ends of the first inner piece 331, a circumferentially compressing force and an axially compressing force produced in the rubber layer existing between both the annular portions 36 and 37 are received by the annular portions 36 and 37 and hence, the circumferentially opposite ends of the first inner piece 331 are difficult to deform. In addition, the second inner piece 332 is disposed between both the annular portions 36 and 37, and the cylindrical inner piece assembly 33 is comprised of the inner ~ pieces 331 and ~ 332. Therefore, ~ the circumferentially and axially compressing forces produced in the rubber layer existing between both the annular portions 36 and 37 ( the rubber layer extending along the second inner piece 332) are all received by the second inner piece 332 and the annular portions 36 and 37 and hence, the circumferentially opposite ends of the inner pieces 331 and 332 are not deformed at all.
The wall thickness of the circumferentially opposite ends of the inner pieces 331 and 332 is smaller than that of the circumferentially central portion. Thus, when the steering handlebar 26 is press-fitted into the left grip 271, the left grip 271,1 is easily elastically deformed according to the . contour of the steering handlebar 26 to facilitate the press-fitting of the steering handlebar 26 into the left grip 27L1 and to ensure the strength against the clamping of the dies in the step of forming the grip body 35.
Specifically, by the fact that the circumferentially 70488-120D ~ --opposite ends of the inner pieces 331 and 332 are formed at a smaller thickness, they are easy to flex, resulting in a relatively increased flexibility of the grip body 35.
Therefore, when the steering handlebar 26 is press-fitted into the left grip 271,1, the grip body 35 is elastically deformed, while following the press-fitting of the steering handlebar 26 , and thus, the steering handlebar 26 can be smoothly press-fitted into the left grip 271,1. In this case, the steering handlebar 26 is guided on the annular portion 36 existing at one end of the inner piece assembly 33 and having a relatively high rigidity and on the annular portion 37 existing at the other end of the inner piece assembly 33 and having a relatively high rigidity, leading to a further improved assemblability of the left grip 271 to the steering handlebar 26.
At the clamping, a substantially vertical force acts on the circumferentially central portions of the inner pieces 331 and 332. However, the inner pieces 331 and 332 are prevented from being cracked or deformed, because the circumferentially central portions of the inner pieces 331 and 332 are formed at the larger wall thickness.
Further, when a driver grasps the left grip 271,1 to drive the motorcycle, a grasping force provided by the palm of a hand of the driver acts on the inner pieces 331 and 332, and places on which the grasping force acts largest are portions corresponding to the circumferentially central portions of the inner pieces 331 and 332. However, because the inner pieces 331 and, 332 are formed at the larger wall thickness at such portions , the grip body 35 , i . a . , the left grip 271 cannot be deformed by the grasping force of the driver.
moreover, because the annular portions 36 and 37 are provided at the axially opposite ends of the first inner piece 331 and the cylindrical inner piece assembly 33 is comprised of the second inner piece 332 and the first inner piece 331 disposed between both the annular portions. 36 and 37, as described above, it is sufficiently possible to oppose the circumferentially compressing force of the inner pieces 331 and 332. Therefore, even if the circumferentially opposite ends of the inner pieces 331 and 332 are formed at a smaller wall thickness, the inner piece assembly 33 cannot be deformed in the cooling course in the formation of the grip body 35.
Additionally, the inner surfaces of the annular portions 36 and 37 are formed into such shapes that they are connected flush with the inner surface of the first inner piece 331 and hence, the shapes of the inner surfaces of the annular portions 36 and 37 are not really circular, but the shapes of the outer surfaces of the annular portions 36 and 37 are formed into a really circular shape. Therefore, the annular portions 36 and 37 have an increased strength, namely, the inner piece assembly 33 has an increased strength.
A plurality of stripe-shaped support projections 42a1 and 42a2 are provided on the inner surfaces of the inner pieces 331 and 332, i.e. , on the inner surface of the inner piece assembly 33 at distances in the circumferential direction of the inner piece assembly 33. These support projections 42a1 and 42a2 extend in the lengthwise direction of the inner piece assembly 33 and are integrally connected to the grip body 35 made of the rubber. The support projections 42a1 and 42az resiliently bear on the outer surface of the steering handlebar 26 press-fitted into the left grip 271.
The inner surfaces of the inner pieces 331 and 33z are provided with a plurality of shallow grooves 43 extending in.
the lengthwise direction of the inner pieces 331 and 332, and a plurality of shallow grooves 44 extending in the circumferential direction of the inner pieces 331 and 33z to interconnect the grooves 43 . The grooves 43 and 44 are provided in a lattice-shaped fashion. The support projections 42a1 and 42az are formed to fill the grooves 43 , and the grooves 43 are formed into an arcuate shape in cross section. Therefore, the resistance to the flowing of the molten rubber within the dies can be suppressed to a smaller level, thereby enabling a smooth filling of the molten rubber. The grooves 44 are also filled with the rubber layers 42b, but the rubber layers 42b are flush with the inner surface of the inner piece assembly 33.
By the fact that the shallow grooves 43 and 44 are provided in the lattice-shaped fashion in the inner surfaces of the inner pieces 331 and 332 in the above manner, the flexibility of the inner pieces 331 and 332 can be further enhanced. Namely, the flexibility of the grip body 35 is further enhanced by the 70488-120D w formation of the lattice-shaped grooves 43 and 44 more than only by the circumferential regulation of the wall thickness of the inner pieces 331 and 332, thereby further facilitating the press-fitting of the steering handlebar 26 into the left grip 271.
If each of the grooves 43 and 44 has a rectangular section, the following problems are arisen: the bottom of each of the grooves 43 and 44 is easily deformed, and each of the grooves has a poor rigidity. However, by the. fact that the.cross-sectional shape of each of the grooves 43 and 44 is arcuate, the rigidity of the bottom of each of the grooves 43 and 44 is increased, and the rigidity and strength of the inner pieces 331 and 332 and thus of the inner piece assembly 33 are increased and hence, when the dies are clamped for the formation of the grip body 35 , there is no possibility that the inner pieces 331 and 332 are deformed.
Moreover, those portions of the inner pieces 331 and 332 which are surrounded by the grooves 43 and 44 are formed into a rectangular shape longer in the axially direction than in the circumferential direction of the inner pieces 331 and 332, thereby providing a structure in which the inner pieces 331 and .. 332 are difficult to deform, during the formation of the grip body 35.
Further, the inner surface of the circumferentially central portion of each of the inner pieces 331 and 332 is of a structure with the axially extending projections 33a, 33a 70488-120D w '~7 formed thereon, because the grooves 43, 43 are defined on the opposite sides . The rigidity and strength of the inner pieces 331 and 332 at their circumferentially central portions are increased even by the projections 33a, 33a.
As best shown in Fig.S, the support projections 42a1 are provided on the inner surface of the first inner piece 331 , while the support projections 42a2 are provided on the inner surface of the second inner piece 332. The cross-sectional shape of each of the support projections 42a1 and 42a2 is trapezoidal, so that the contact area with the steering handlebar 26 is extremely small. Therefore, the amount of heat transmitted from the inner pieces 331 and 332 to the steering handlebar 26 can be extremely decreased, and the strength of adhesion between the inner pieces 331 and 332 and the support projections 42a1 and 42a~ can be extremely increased. Further, each of the support projections 42a1 and 42a2 is formed to have a larger width than the width of the grooves 43 , leading to a structure in which the strength of adhesion between the inner pieces 331 and 332 and the support projections 42a1 and 42a2 is correspondingly increased.
The width d2 of the support projections 42a2 of the second inner piece 332 is formed larger than the width dl of the support projections 42a1 of the first inner piece 331. Thus, the strength of adhesion between the left grip 27L1 and the steering handlebar 26 on the side of the second inner piece 332 can be ensured , and the heat insulating property can be more enhanced 70488-120D w on the side of the first inner piece 331. Both of the heat insulating property and the adhesion strength are satisfied.
The area of contact between the steering handlebar 26 and the left grip 27L1 is smaller on the side of the first inner piece 331 than on the side of the second inner piece 332, because the width d2 of the support projections 42az of the second inner piece 33z is larger than the width dl of the support projections 42a1 of the first inner piece 331. Namely, the area of an air heat-insulating layer formed between the steering handlebar 26 and the first inner piece 331 is larger than that of an air heat-insulatinglayer formed between the steering and handlebar 26 and the. second inner piece 33Z, so that the first inner piece 331 touched by fingertips when the grip body 35 has been grasped by a hand (in a state shown in Fig.6) is warmed without escaping of the heat, more than the second inner piece 332.
A pair of notches 45, 45 are provided at circumferentially opposite end edges of the first inner piece 331 at a distance spaced apart from each other in the lengthwise direction of the first inner piece 331, while notches 46, 46 are provided at circumferentially opposite end edges of the second inner piece 332. The notches 46 define openings 47, 47 by cooperation with the notches 45 , 45 of the first inner piece 331. In the formation of the grip body 35 , the molten rubber flows through the openings 47, 47 into the grooves 43 and 44 in the inner piece assembly 33 to form the support projections 42a1 and 42a2 and the rubber layers 42b integrally connected to the grip body 35. Moreover, the notches 45, 45 and 46, 46 are rectangular, but corners of the notches 45, 45 and 46, 46 are curved and thus, each of peripheral edges of the notches 45, 45 and 46, 46 has an increased strength.
Openings 48 and 49 are also defined between the longitudinally opposite ends of the second inner piece 332 and the annular portions 36 and 37 of the first inner piece 331, respectively. The molten rubber also flows through the openings 48 and 49.into the grooves 43 and 44 in the inner piece assembly 33 , whereby the molten rubber can be promptly filled all inside and outside the inner piece assembly 33.
An inner surface of one 36 of the annular portions of the first inner piece 331 is provided circumferentially at a distance spaced apart from each other with a plurality of positioning abutment projections 50 for abutment against an outer surface of the core die 82 and alignment of the axes upon mounting of the inner piece assembly to the core die 82, and positioning notches 51 for achieving the circumferential alignment within the forming mold by engagement with the core die 82.
A rubber layer is formed in the inner surface of the annular portion 36 excluding the positioning notch 51 to extend to the entire periphery of the opened edge , as shown in Figs . 2 and 4 , thereby providing a structure in which the rubber layer formed on the inner surface of the inner piece assembly 33 is difficult to peel off, when the steering handlebar 26 is press-fitted into the left grip 27c1.
A plurality of positioning projections 52 are provided on the other annular portion 37 at locations circumferentially spaced apart from one another to define recesses 53 between the positioning projections 52, so that the axial positioning of the inner piece assembly 33 within the forming mold can be achieved by abutment of the projections 52 against the forming mold. Each of the recesses 53 functions_as an opening for flowing of the molten rubber into the inner piece assembly 33.
By the fact that the positioning abutment projections 50 and the positioning notches 51 are provided on the inner surface of the annular portion 36 and the positioning projections 52 are provided on the annular portion 37 to define the recesses 53 each functions as the opening for flowing of the molten rubber into the inner piece assembly 33 , as described above , the inner pieces 331 and 332 can be positioned correctly within the mold system including the core die 82 , the upper die and the lower die 83, whereby the grip body 35 can be appropriately formed.
The heater 34~ is an FPC heater having a sectional structure with a copper foil strip pattern sandwiched between a base film and an overlying film. The heater 34~ is of a substantially rectangular shape, as shown in Fig.7, when it is in a developed state.
The heater 34~ includes a first heater region 34a having a size corresponding to the first inner piece 331, a second heater region 34b having a size corresponding to the second inner piece 332, and a connecting region 34c extending from the first heater region 34a toward the annular portion 36 of the first inner piece 331.
A pair of connecting lands 6l and 62 are formed in the connecting region 34c by exposure of a copper foil, and connecting wires 73 and 74 extending from the cord 72 are to the connecting lands 61 and 62 by soldering portions 75 and 76 , respectively.
A first heater circuit pattern portion P1~, is formed in the first heater region 34a and connected to the connecting land 61 by a connecting portion 63 disposed at a location near the connecting region 34c. A second heater circuit pattern portion P2A 1S formed in the second heater region 34b and connected to the connecting land 62 by a connection portion 64 disposed at a location near the connecting region 34c. Moreover, the strip pattern of each of the heater circuit pattern portions P1A and P2n is formed to extend mainly longer in the circumferential direction of the inner piece assembly 33, when the heater 34~
is wound around the inner piece assembly 33. Thus, when the heater 34~ is wound around the inner piece assembly 33, each of the heater circuit pattern portions P1A and PzA is difficult to wrinkle.
The first heater region 34a is formed sufficiently longer in the lengthwise direction of the heater 34L, so that all the fingers of a hand can be warmed. The second heater region 34b is formed shorter than the first heater region 34a, so that the openings 48 and 49 for flowing-in of the molten rubber cannot be occluded. When the heater 34~ has been positioned and wound around the inner piece assembly 33 , the first heater region 34a is disposed in correspondence to the first inner piece 331, and the second heater region 34b is disposed in correspondence to the second inner piece 33z.
The first and second heater circuit pattern portions P1A
and PZA are connected to each other by a connecting portion 65 adjacent the connecting portion 64. . Moreover, the connecting portions 64 and 65 are disposed at a location on the side of the axially inner end of the inner piece assembly 33 (at a location in the vicinity of the thumb when the left grip 271 has been grasped) , which is a site most difficult to deform in the assembling of the left grip 271 to the steering handlebar 26, thereby providing a structure in which the connecting portions 64 and 65 are difficult to break by an external load.
Namely, a larger load is applied to the axially outer end of the inner piece assembly 33 as a result of being pushed by the outer end of the steering handlebar 26 which is press-fitted, but a relatively small load is applied to the axially inner end of the inner piece assembly 33 and hence, there is ... correspondingly not a possibility of a breaking.
Pluralities of larger and smaller copper foil land portions 57 and 58 for reinforcing the heater 34~ are formed in the first and second heater regions 34a and 34b, respectively, and do not function as a heater circuit pattern . Bores 59 are defined at a plurality of points in each of the copper foil land portions 57 and 58, so that when the heater 34L is wound around the inner piece assembly 33 , the molten rubber is filled in the bores 59 to achieve the reliable adhesion of the heater 34~ to the inner piece assembly 33.
. Elongated bores 66, 66 corresponding to the openings 47, 47 of the inner piece assembly 33 are defined in the heater 34 between the first and second heater regions 34a.and 34b. The elongated bores 66 , 66 are formed larger than the openings 47 , 47, so that even if the relative positions of the inner piece assembly 33 and the heater 34~ are slightly misaligned from each other, the openings 47, 47 cannot be occluded by the heater 34~.
Band-shaped copper foil-non-formed regions 67 are formed in the heater 34~ to connect the elongated bores 66 , 66 to each other, and the flexibility of the heater 34L is enhanced by the copper foil-non-formed regions 67.
A pair of flanges 80 and 81 are provided on the annular portion 36 of the first inner piece 331 to define a mounting groove 70 therebetween. Moreover, the axially inner flange 81 is formed with a height and a thickness smaller than those of the axially outer flange 80, as shown in Fig.4, into a structure in which when the inner piece assembly 33 has been embedded in the rubber layer of the grip body 35, the radially outer end of the Flange 81 is difficult to protrude onto a slant surface of the flange portion 32.
A portion of the axially inner flange 81 is notched in correspondence to the circumferentially central portion of the first inner piece 331, a pair of positioning pins 68, 68 are projectingly provided on the first inner piece 331 in correspondence to such notches. On the other hand, the heater 34~ is wound around the outer periphery of the inner piece assembly 33 in such a manner that the connecting region 34c extends toward the annular portion 36 at the circumferentially central portion of the first inner piece 331, and the heater 34~ is positioned relative to the inner piece assembly 33 by bringing the positioning pins 68 into engagement into the positioning bores 69, 69 provided in the connecting lands 61 and 62 of .the heater 34~ . The notches of the flange 81 and tip ends of the positioning pins 68 are rounded, so that the heater 34~ is not damaged when being wound around the inner piece assembly 33.
Moreover, in a state in which the heater 34~ has been wound around the inner piece assembly 33 , the soldering portions 75 and 76 are in positions in which they are sandwiched between the axially outer flange 80 and the positioning pins 68, 68.
Thus, it is avoided to the utmost that other members strike the soldering portions 75 and 76 to produce a connection failure.
In addition, when the left grip 271 has been grasped by a hand, the soldering portions 75 and 76 are in positions in which a grasping force is difficult to act on them. Further, by the fact that the soldering portions 75 and 76 are disposed in a downward turned attitude between the upper die and the lower ' 35 die 83 in forming the grip body 35 in the mold, the load acting on the soldering portions 75 and 76 by the clamping of the mold is also decreased.
A cord support portion 71 is provided with the annular portion 36 at circumferentially one end of the first inner piece 331 and formed to traverse the mounting groove 70. The electrically feeding cord 72 is disposed in the mounting groove 70 ; wound around the annular portion 36 ; passed through the cord support portion 71 and led out to the outside. . A cylindrical portion 78 for guiding and supporting the led-out portion of the cord 72 is projectingly provided on the flange portion 32 of the grip body 35 . Thus , the cord 72 is folded back at the cord support portion 71 and led out to the outside, and an external force acting on the cord 72 is received by the cord support portion 71 and hence, the external force and load cannot be applied to the soldering portions 75 and 76.
A portion of the axially inner flange 81 has the same height in level as the axially outer flange 80, and the cord support portion 71 is bridged between those portions of the flanges 80 and 81 which have the same height. Moreover, a contact surface 71a of the cord support portion 71 with the cord 72 is formed into an arcuate shape in a direction substantially parallel to the axial direction of the inner piece assembly 33 , so that the cord 72 can be led out from the cord support portion 71 in a direction substantially perpendicular to the axial direction of the inner piece assembly 33 without being tilting down and can be prevented to the utmost from being damaged at the folded-back portion thereof.
The cord 72 is a silicon-coated cord and is excellent in weatherability, heat resistance and flexibility, as compared with the conventional vinyl-coated cord. Further, the cord 72 is of a cabtyre cable str-ucture, as shown in Fig.l2. If the cord is of the cabtyre cable structure in the formation of the grip body 35, there is a possibility that a soft silicon-coated portion of the cord may be compressed by a pressure of the molten rubber. However, the pressure acting on the cord 72 can be escaped by the fact that a portion of the molten rubber in the upper die, and the lower die 83 flows out through a gap between the insertion bore 84 and the cord 72 . Thus , during formation of the grip body 35, the cord 72 cannot be cut by the pressure of the rubber.
Referring to Figs.l3 and 14, the right grip 2781 is comprised of the inner piece assembly 33 formed cylindrically, and a sheet-shaped heater 34R wound around the substantially entire periphery of the outer surface of the inner piece assembly 33 , the inner piece assembly 33 and the sheet-shaped heater 34R being integrally embedded in a grip body 35 made of a rubber. The right grip 2781 is mounted on a throttle pipe 79 which is turnably mounted at the right end of the steering handlebar 26, and is formed with an inside diameter larger than that of the left grip 271 directly mounted on the steering handlebar 26.

More specifically, in place of the pluralities of support projections 42a1 and 42az provided on the inner periphery of the left grip 271, sliced flat support portions 42' are formed at a low height in the right grip 2781. Thus, the support portions 42' are brought into contact with the throttle pipe 79 , so that the strength of adhesion of the right grip 2781 and the throttle pipe 79 is increased, and a wider heat-insulating air layer 85 is formed between the right grip 2781 and the throttle pipe 79,.thereby suppressing the transmission of a.heat to the throttle pipe 79.
Another arrangement of the right grip 2781 is similar to that of the left grip 27L1-Referring to Fig.lS, a grip heater unit 92 is constituted by the heaters 34L and 34R installed in the left and right grips 271 and 2781 and connected in series to each other, and a control device 91 for controlling the supplying of an electric power to the heaters 34~ and 34R.
Led out of the grip heater unit 92 are a plus-side connecting wire 94 connected to a plus side of a battery 90 serving as a power source mounted on the motorcycle, and a minus-side connecting wire 95 connected to ( grounded to ) a minus .- side of the battery 90. A serial circuit comprised of the heaters 34~ and 34R is connected at one end thereof to the plus-side connecting wire 94 and at the other end thereof to the control device 91.
The control device 91 includes a switch 96 connected to the plus-side connecting wire 94, a surge absorber 97, a diode 98, a constant-voltage outputting means 99, a periodic voltage generating means 100, a proportional voltage outputting means 101 , a fail-safe means 102 , a driving-signal outputting means 103 as a rectangular-wave signal outputting means, a battery voltage monitoring means 104, a resistor 105, a field-effect transistor 106 as a switching means, a surge absorber 107, and a capacitor 108 for removing an electrostatic noise.
The surge absorber 97 and. the diode 98 are connected to between the switch 96 and the constant-voltage outputting means 99. The field-effect transistor 106 is connected to the other end of the serial circuit comprised of the heaters 34~ and 34R
and connected at one end thereof to the plus-side connecting wire 94. The surge absorber 107 and the capacitor 108 are connected between the serial circuit and the field-effect transistor 106. Further, the resistor 105 is connected in series between the driving-signal outputting means 103 and a gate of the field-effect transistor 106.
The constant-voltage outputting means 99 is adapted to output a predetermined constant voltage Vc based on a voltage supplied from the battery 90 and inputted from the plus-side . - connecting wire 94 through the surge absorber 97 and the diode 98 upon turning-on of the switch 96. The constant-voltage outputting means 99 includes a resistor 110 and a Zener diode 111 which are connected in series between the diode 98 and a ground potential, a smoothing capacitor 112 connected to 70488-120D '-' 39 between the diode 98 and the resistor 110, and a smoothing capacitor 113 connected in parallel to the Zener diode 111.
The periodic voltage generating means 100 is adapted to output a triangular wave voltage Vt varied at a predetermined cycle based on the constant voltage Vc outputted from the constant-voltage outputting means 99. The periodic voltage generating means 100 includes resistors 114 and 115 connected to the constant-voltage outputting means 99, an operational amplifier 116 having a non-inverted-input terminal connected to a point of connection between the resistors 114 ands 115, a capacitor 117 provided between an inverted input terminal of the operational amplifier 116 and the ground potential, a resistor 118 provided between an output terminal and the inverted input terminal of the operational amplifier 116 , and a chattering-preventing resistor 119 provided between the output terminal and the non-inverted input terminal of the operational amplifier 116. In the operational amplifier 116, a reference voltage Vd obtained from the division of a voltage at the resistors 114 and 115 is compared with a charging voltage (a triangular-wave voltage Vt) in the capacitor 117, and the triangular-wave voltage Vt is outputted by charging or discharging of the capacitor 117 through the resistor 118 by an output from the operational amplifier 116.
The proportional voltage outputting means 101 is adapted to output a temperature adjusting comparative voltage Vp based on the constant voltage Vc outputted from the constant-voltage outputting means 99. The proportional voltage outputting means 101 includes a variable resistor 120 and a resistor 121 connected in series between the constant voltage Vc and the ground potential, a resistor 122 connected in parallel to the variable resistor 120, and a resistor 123 connected to a contact which is in sliding contact with the variable resistor 120.
The driving-signal outputting means 103 is adapted to output a driving signal V~. which is a rectangular wave, by comparing the triangular wave voltage Vt'outputted from the.
periodic voltage generating means 100 with a comparative voltage Vp outputted from the comparative voltage outputting means 101. The driving-signal outputting means 103 includes an operational amplifier 124 having a non-inverted input terminal to which the proportional voltage Vp is inputted and an inverted input terminal to which the triangular wave voltage Vt is inputted, and a chattering-preventing resistor 125 provided between an output terminal and the non-inverted input terminal of the operational amplifier 124 . The output terminal of the operational amplifier 124 is connected to a gate of the field-effect transistor 106 through the resistor 105. The operational amplifier 124 is adapted to output a rectangular . . driving signal Vo~T which is brought into a high level ( a level corresponding to the constant voltage Vc) when the triangular wave voltage Vt is lower than the comparative voltage Vp , and into a low level ( a level corresponding to the ground potential ) when the triangular wave voltage Vt is higher than the comparative voltage Vp. This causes the field-effect transistor 106 to be turned ON or OFF, thereby controlling the supplying of the electric power to the heaters 34~ and 34R.
More specifically, when the triangular wave voltage Vt is outputted from the periodic voltage generating means 100, as shown in Fig . 16 ( a ) , the rectangular driving signal VouT which is brought into a high level as the triangular wave voltage Vt becomes ~.arger than the comparative voltage Vp, is outputted from the driving signal outputting. means 103 , as shown in Fig.l6(b). By varying the comparative voltage Vp by the comparative voltage outputting means 101, the ratio of the ON-time to OFF-time of the heaters 34~ and 34R (a duty ratio) can be varied, thereby controlling the biased amount of electric power to the heaters 34~ and 34R.
The fail-safe means 102 includes a resistor 126 provided between the non-inverted input terminal of the operational amplifier 124 into which the comparative voltage Vp is inputted, and the ground potential. The resistance value of the resistor 126 is set at a value sufficiently larger than that of the variable resistor 120 in the comparative voltage outputting means 101. Thus, when the comparative voltage Vp from the comparative voltage outputting means 101 becomes unstable, the output from the driving signal outputting means 103 is brought into a low level in such a manner that the comparative voltage Vp is brought into the ground potential, thereby stopping the supplying of the electric power to the heaters 34~ and 34R.

The battery voltage monitoring means 104 is adapted to monitor the power source voltage Vb of the battery 90 obtained between the diode 98 and the constant voltage outputting means 99 upon turning-on of the switch 96 to determine whether the driving signal can be outputted from the driving signal outputting means 103. The battery voltage monitoring means 104 includes resistors 127 and 128 connected in series between the diode 98 and the ground potential to divide the power source voltage Vb to provide a proportional voltage Vb', a noise.
removing capacitor 129 connected in parallel to the resistor 128, resistors 130 and 131 connected in series between the constant voltage outputting means 99 and the ground potential to divide the constant voltage Vc outputted from the constant voltage outputting means 99 to provide a reference voltage (a voltage threshold value ) , an operational amplifier 132 having an inverted input terminal to which the proportional voltage Vb' is inputted and a non-inverted input terminal to which the reference voltage is inputted, a hysteresis setting resistor 133 connected between an output terminal and the non-inverted input terminal of the operational amplifier 132 , an operational amplifier 134 having an inverted input terminal to which the .. output terminal of the operational amplifier 132 is connected and a non-inverted input terminal to which the non-inverted input terminal of the operational amplifier 132 is connected, and a resistor 135 connected between the inverted input terminal of the operational amplifier 134 and the-constant voltage outputting means 99. The output terminal of the operational amplifier 134 is connected to the non-inverted input terminal of the operational amplifier 124 in the driving signal outputting means 103.
In such battery voltage monitoring means 104, when the output from the operational amplifier 132 is brought into a low level , the output from the operational amplifier 134 is brought into a.high level, and the comparative voltage Vp inputted to the non-inverted input terminal of the operational amplifier 124 in the driving signal outputting means 103 cannot be varied.
Thus, the supplying of the power to the heaters 34L and 34R is controlled in an ON-OFF manner in accordance with the comparative voltage Vp. Namely, the operational amplifier 134 outputs a permitting signal for permitting the outputting of the driving signal from the driving signal outputting means 103 as a high level signal. On the other hand, when the output from the operational amplifier 132 is brought into a high level, the output from the operational amplifier 134 is brought into a low level, and the output from the operational amplifier 124 is forcibly reduced to a low level by drawing the comparative voltage Vp inputted to the non-inverted input terminal of the -- operational amplifier 124 in the driving signal outputting means 103 to the operational amplifier 134, thereby stopping the supplying of the power to the heaters 34~ and 34R. Namely, the operational amplifier 134 outputs a prohibiting signal for prohibiting the outputting of the driving signal from the ' 44 - driving signal outputting means 103 as a low level signal.
A positive feedback is provided to the operational amplifier 132 in the battery voltage monitoring means 104 by the resistor 133 , so that the proportional voltage Vb ' inputted to the operational amplifier 132 is substantially decreased when being dropped, and substantially increased when being risen. Therefore, the hysteresis of the reference voltage, i.e., the voltage threshold value is substantially established - in the operational -amplifier 134. When the proportional voltage Vb' is dropped, a first voltage threshold value VS1 is compared with the proportional voltage Vb', and when the proportional voltage Vb' becomes lower than the first voltage threshold value VS1, a high level signal is outputted from the operational amplifier 134. When the proportional voltage Vb' is risen, a second voltage threshold value VSZ larger than the first voltage threshold value VS1 by a predetermined value or more is compared with the proportional voltage Vb', and when the proportional voltage Vb' becomes equal to or larger than the second voltage threshold value VSZ, a low level signal is - outputted from the operational amplifier 134.
In other words, when the proportional voltage Vb' is - - varied as shown in Fig . 17 ( a ) , a prohibiting signal of a low level is outputted from the battery voltage monitoring means 104 , i . a . , from the operational amplifier 134 , as the proportional voltage Vb' is dropped to become smaller than the first voltage threshold value V51, and in response to this , the driving signal from the driving signal outputting means 103 is forcibly brought into a low level as shown in Fig.l7(b). In addition, the high-level permitting signal is outputted from the battery voltage monitoring means 104 , as the proportional voltage Vb' is risen to become equal to or larger than the second voltage threshold value VS2, and in response to this, the high-level driving signal is outputted from the driving signal outputting means 103, as shown in Fig.l7(b).
The first voltage threshold value VS1 is set according to the following equation:
Vsl = VM - ~VL t OV
wherein VH represents a necessary minimum power source voltage required in the battery 90 to allow the motorcycle to travel;
OVl represents a decrement of voltage dropped in the wire from the battery 90 to the battery voltage monitoring means 104; and OVZ represents a detected maximum voltage error presumed on the plus side in the battery voltage monitoring means 104. When the necessary minimum power source voltage VM is set at 12.5 V which required, for example, to operate a starter motor 144 (see Fig.20); the dropped-voltage decrement OVl is set at 0.5 V; and the detected maximum voltage error OVZ on the plus side is set at 0.3 V, the first voltage threshold value VS1 is set at 12 . 3 V . The second voltage threshold value VSZ is set larger than the first voltage threshold value VS1, for example, by the dropped-voltage decrement 4V1 ( 0 _ 5 V) or more, and when the first ' 46 voltage threshold value VS1 is 12.3 V, the second voltage threshold value VSZ is equal to or more than 12.8V.
The control device 91 arranged as described above is disposed on a base plate 139 installed in a control box 138 shown in Figs . 18 and 19 . A knob 140 is disposed on a surface of the control box 138 for turning ON and OFF the switch 96 in the control device 91 and for performing the sliding of a contact of the variable resistor 120. Thus, the switch 96 can be turned OFF by bringing the knob 140 to an "OFF" position, and the resistance value of the variable resistor 120 can be varied to the regulate the temperature of the heaters 34~ and 34R by turning the knob 140 between an "LO" position and an "HI" position.
Moreover, the control box 138 is disposed at a location near the left grip 271 of the steering handlebar 26, as shown in Fig. 1.
Referring to Fig.20, one end of a main switch 142 or a combination switch having a main switch function is connected to the plus side of the battery 90 through a main fuse 141, and a starter motor 144 is also connected to the plus side of the battery 90 through a relay switch 143. A charger 146 is connected between the main fuse 141 and the main switch 142, and adapted to rectify AC power obtained in an AC generator 145 to supply a charging power with the battery 90.
The minus side of the battery 90, the starter motor 144 and the charger 146 are grounded at grounding portions EA, EB
and E~ established at different points on an engine case in an 70488-120D ' ' ~ 47 engine mounted on the motorcycle. An earth wire 147 connected to the grounding portion E~ is connected to the steering handlebar 26.
Fuses 148 , 149 and 150 are connected in parallel to the other end of the main switch 142. The fuse 148 is connected to the grounding portion E~ through a serial circuit comprised of a starter switch 151 and a relay coil 152, and the fuse 149 is connected to the grounding portion E~ through a serial circuit comprised of a head lamp switch 153 and the head lamp 22. The starter switch 151 is disposed at the right end of the steering handlebar 26 , so that the relay switch 143 is turned ON by exiting the relay coil 152 by turning ON the starter switch 151 , thereby supplying a power with the starter motor 144. The head lamp switch 153 is disposed at the right end of the steering handlebar 26.
The fuse 150 is connected to one end of a winker relay 154. The left and right front winker lamps 23L and 23R disposed on the front fork 21 are connected at one ends thereof to the other end of the winker relay 154 through a winker switch 155 for selectively switching-over the lighting of the front winker lamps 23~ and 23R, and are capable of being connected at the .. other ends thereof to the grounding portion E~ through connecting terminals 156a and 156b connected to each other.
Moreover, the winker switch 1SS is disposed at the left end of the steering handlebar 26.
One end of a stop switch 158 is capable of being connected ' 48 between the fuse 150 and the winker relay 154 through connecting terminals 157a and 157b connected to each other. The other end of the stop switch 158 is connected to the grounding portion E~ through a stop lamp 159. Moreover, the stop switch 158 is disposed at the right end of the steering handlebar 26.
The plus-side and minus-side connecting wires 94 and 95 are led from the grip heater unit 92 which comprises the serial circuit including the heaters 34~ and 34R and the control device 91 . The plus-side connecting wire 94 is connected. to one end of an interruptive connecting wire 161 having a fuse 160 , and the minus-side connecting wire 95 is connected to one end of an interruptive connecting wire 163. Thus, the other end of the interruptive connecting wire 161 is interruptively connected, at a location near the stop switch 158, between the main switch 142 for switching-over the connection and disconnection with the plus side of the battery 90 and the stop switch 158 as a first electric part disposed on the steering handlebar 26 , a . g . , between the fuse 150 connected to the main switch 142 and the stop switch 158 in this embodiment. In addition, the other end of the interruptive connecting wire 163 is interruptively connected between the front winker lamps 23~
.. and 23R as second electric parts disposed on the front fork 21 which is a member turned in unison with the steering handlebar 26, and the minus side of the battery 90, i.e., the grounding portion E~ at a location near the front winker lamps 23~ and 23R.

' 49 - Referring also to Fig.2l, the other end of the interruptive connecting wire 161 connected to the plus-side connecting wire 94 is interruptively connected between the fuse 150 and the stop switch 158, for example, through a three-forked branch connecting wire 164. Namely, the branch connecting wire 164 is provided with connecting terminals 166a, 166b and 166c which are connected respectively to a connecting terminal 165 - provided at the- other end of the interruptive connecting wire 161 and connecting terminals 157a and 157b for connecting the fuse 150 to the stop switch 158.
The other end of the interruptive connecting wire 163 connected to the minus-side connecting wire 95 is also interruptively connected between the left and right front winker lamps 23~ and 23R and the grounding portion E~, for example, through a three-forked branch connecting wire 168 . Namely, the branch connecting wire 168 is provided with connecting terminals 170a, 170b and 170c which are connected respectively to a connecting terminal 169 provided at the other end of the interruptive connecting wire 163 and the connecting terminals 156a and 156b for connecting the left and right front winker lamps 23L and 23R to the grounding portion E~.
With such electrical connection structure, by the fact that the plus-side connecting wire 94 and the minus-side connecting wire 95 led from the grip heater unit 92 are interruptively connected between the fuse 150 and the stop switch 158 connected to the plus side of the battery 90 through the main fuse 141 and the main switch 142 and between the left and right front winker lamps 23L and 23R and the grounding portion Ec, the grip heater unit 92 can be connected to the plus side and the minus side of the battery 90 and mounted on the vehicle , while avoiding the mis-operation of the stop switch 155 and the left and right front winker lamps 23~ and 23R, even if the heaters 34~ and 34R are operated.
Moreover, by the fact that the stop switch 155 is disposed on the steering handlebar 26 and.the front winker lamps 23~ and.
23R are disposed on the front fork 21 operated in unison with the steering handlebar 26, the wiring portions connected to the stop switch 155 and the front winker lamps 23~ and 23R are arranged, so that they are not twisted, even if the steering handlebar 26 is turned. In such wire portions, particularly, the connection structure interruptively connected to the disposed portions in the vicinity of the steering handlebar 26 , no problems are arisen in its durability and reliability.
In a vehicle such as a motorcycle, a snowmobile and a three-wheeled buggy, it is common that the wiring portion between the stop switch 155 and the main switch 142 and the wiring portions of the left and right front winker lamps 23~ and 23R
to the grounding portion E~ are located in vicinity of the steering handlebar 26, and the general-purpose utilization of the electric connection of the grip heater unit 92 to a common vehicle can be easily achieved in such a manner to perform the interruptive connection to such wiring portions.

Further, in the battery voltage monitoring means 104 in the control device 91, the first voltage threshold value Vsl for stopping the supplying of the power to the heaters 34~ and 34R is determined according to the equation, Vsl = VM - QVl +
AVz, wherein VM represents a necessary minimum power source voltage required in the battery 90 to allow the motorcycle to travel; QV1 represents a decrement of voltage dropped in the wire from the battery 90 to the battery voltage monitoring means 104; and QVZ represents a detected maximum voltage error presumed on the plus side in the battery voltage monitoring means 104. Therefore, the first voltage threshold value Vsl is set at an extremely small level, while ensuring the necessary minimum power source voltage required in the battery 90 to allow the motorcycle to travel, after taking the dropped-voltage decrement and the detected error of voltage in the battery voltage monitoring means 104 into consideration. Thus, it is avoided that the supplying of the power to the heaters 34~ and 34R is performed even if the first voltage threshold value Vsl becomes equal to or smaller than the minimum power source voltage required in the battery 90 , and the chances to be able to warm the left and right grips 271 and 2781 by the heaters 34~ and 34R can be extremely increased. Further, by the fact that the supplying of the power from the battery 90 to the heaters 34~ and 34R is permitted at the second voltage threshold value Vsz higher than the first voltage threshold value Vsl by the predetermined value or more, the turning ON and OFF of the supplying of the power to the heaters 34~ and 34R cannot be frequently repeated, and the control of the supplying of the power to the heaters 34~ and 34R can be stabilized to stably warm the left and right grips 271 and 2781, thereby providing a good warm-feeling.
Moreover, the voltage monitored in the battery voltage monitoring means 104 is provided by the interruptive connecting wire 161 interruptive.ly connected to the plus side of the stop .
switch 155, and the voltage dropped due to the passing through the main fuse 141, the main switch 142 and the fuse 150 from the battery 90 is monitored and as a result, no exclusive resistor is required. When the voltage becomes lower than the first voltage threshold value VS1 as a result of a voltage drop produced in the interruptive connection point of the interruptive connecting wire 161 due to the lighting of the stop lamp 159 by the turning ON of the stop switch 155, the supplying of the power to the heaters 34~ and 34R is immediately stopped, and the lighting of the stop lamp 159 is preferentially maintained.
Fig.22 illustrates a second embodiment of the present invention, wherein portions or components corresponding to those in the first embodiment are designated by like reference characters.
In the first embodiment, the head lamp 22 and the left and right front winker lamps 23~ and 23R have been mounted on . 53 the front fork 21 turned in unison with the steering handlebar 26, but they may be mounted, for example, on a cowling on the vehicle body frame. In this case, the minus-side connecting wire 95 as the second connecting wire led from the grip heater unit 92 is connected to the steering handlebar 26, for example, - by co-clamping, along with the earth wire 147 connected to the grounding portion E~. In addition, the plus-side connecting wire 94 as the first connecting wire is interruptively connected between the stop switch 155 and the fuse 150, as in the first embodiment.
With the second embodiment, by the fact that the minus-side connecting wire 95 is connected to the steering handlebar 26, the minus-side connecting wire 95 cannot be twisted even if the steering handlebar 26 is turned, thereby providing an effect similar to that in the first embodiment.
In the above-described embodiments, the plus-side connecting wire 94 of the grip heater unit 92 has been interruptively connected between the stop switch 155 and the fuse 150, but the plus-side connecting wire 94 may be interruptively connected between the head lamp switch 153 and the fuse 149. However, there is a vehicle in which a power supplied to the head lamp 22 is an AC power and hence, when the power is supplied from the battery 90 to the heaters 34~ and 34R, the interruptive connection of the plus-side connecting wire 94 is impossible. To provide the general-purpose utilization of the connection, it is desirable that the ~ ' 54 plus-side connecting wire 94 is interruptively connected between the stop switch 155 and the main switch 142.
In addition, the power of the battery 90 has been used as the power source in the above-described embodiments , but the present invention is also applicable to a vehicle in which the heaters 34~ and 34R are energized by an AC power from the AC
generator 145.
Figs . 23 to 30 illustrate a third embodiment of the present invention, wherein portions or components corresponding to.
those in each of the above-described embodiments are designated by like reference characters.
Referring to Figs.23 to 28, a left grip 272 is comprised of an inner piece assembly 33 formed into a cylindrical shape, and a sheet-shaped heater 174 wound around substantially the entire periphery of an outer surface of the inner piece assembly 33. The inner piece assembly 33 and the sheet-shaped heater 174 are integrally embedded in a grip body 35 made of a rubber.
Support projections 42a are formed at a plurality of circumferentially spaced-apart points on inner surfaces of inner pieces 331 and 33z , i . a . , on an inner surface of the inner piece assembly 33 to fill grooves 43 in the inner surface of the inner piece assembly 33. The support projections 42a extend in a lengthwise direction of the inner piece assembly 33 and are integrally connected to the grip body 35. The support projections 42a resiliently bear on an outer surface of the steering handlebar 26 press-fitted into the left grip 27L2.

70488-120D '-Moreover, the width of the support projections 42a in the circumferential direction of the inner piece assembly 33 is constant.
The structure of a section excluding the heater 174 and the shapes of the support projections 42a is basically the same - as the left grip 27L1 in the first embodiment and hence, the portions corresponding to the structure of the left grip 27L1 in the first embodiment are only shown with the same reference characters as in the first embodiment being affixed in Figs.
23 to 28, and the detailed description thereof is omitted.
Referring to Fig.29, the heater 174 is constituted as an FPC heater and has a sectional structure in which a strip pattern formed of a copper foil 55 as a heat generating element is laminated between a base film 56a and an overlying film 56b ( see Fig. 26 and omitted and not shown in Fig. 29 ) . The heater 174 includes a first rectangular heater region 174a substantially corresponding to the outer periphery of the first inner piece 331 excluding the annular portions 36 and 37, a second rectangular heater region 174b substantially corresponding to the outer periphery of the second inner piece 332, and a connecting region 174c led from the first heater region 174a toward the annular portion 36 of the first inner piece 331.
First and second heater circuit pattern portions P1H and P2H having different densities of the copper foil 55 dispersed are formed on the first heater region 34a by the strip pattern of the copper foil 55. The heater circuit pattern portions P18 and P28 are connected in series in such a manner that half of the first heater circuit pattern portion P1H is connected to one end of the second heater circuit pattern portions P2e, and the other end of the second heater circuit pattern portions P28 is connected to remaining half of the first heater circuit pattern portions P1H. Moreover, the first heater circuit pattern portions PlB having the density of the copper foil 55 - dispersed higher than that of the second heater circuit. pattern portions,P2B is disposed in a location inner in the widthwise direction of the motorcycle , i . a . , adjacent an inner end of the grip body 35, when a portion of the first heater region 174a which is near the connecting region 174c and corresponds to the annular portion 36, i.e. , the left grip 27L2, has been mounted on the steering handlebar 26 . The second heater circuit pattern portions PzB having the density of the copper foil 55 dispersed lower than that of the first heater circuit pattern portions Pls is disposed in a location outer in the widthwise direction of the motorcycle, i.e. , adjacent an outer end of the grip body 35, when the left grip 27LZ has been mounted on the steering handlebar 26.
Third and fourth heater circuit pattern portions P3B and Pas having different densities of the copper foil 55 dispersed are formed in the second heater region 174b by the strip pattern of the copper foil 55. The third and fourth heater circuit pattern portions P38 and P,8 are connected in series in such a manner that half of the third heater circuit pattern portion P3H is connected to one end of the fourth heater circuit pattern portion P4H, and the other end of the fourth heater circuit pattern portion P,H is connected to remaining half of the third heater circuit pattern portion P3H. Moreover, the density of _ the copper foil 55 dispersed in all the third and fourth heater circuit pattern portions P~e and P,H in the second heater region 174b is set lower than the density of the copper foil 55 dispersed in all the first and second heater circuit pattern portions P1a and P28 in the first heater region 174a. The third heater circuit pattern portion P3B having the density of the copper foil 55 dispersed higher than that of the fourth heater circuit pattern portion P4g is disposed in a location inner in the widthwise direction of the motorcycle, i.e. , adjacent the inner end of the grip body 35, when a portion of the second heater region 174a adjacent the connecting region 174c, i.e. , the left grip 27LZ, has been mounted on the steering handlebar 26. The fourth heater circuit pattern portion P48 having the density of the copper foil 55 dispersed lower than that of the third heater circuit pattern portion P3g is disposed in a location outer in the widthwise direction of the motorcycle, i.e., adjacent the outer end of the grip body 35, when the left grip 272 has been mounted on the steering handlebar 26.
Moreover, the strip patterns of the heater circuit pattern portions P1H to P4g are formed to extend longer in the circumferential direction of the inner piece assembly 33 , when 70488-120D '-the heater 174 is wound around the inner piece assembly 33.
Thus, during winding the heater 174 around the inner piece assembly 33 , wrinkles are difficult to be produced in each of the heater circuit pattern portions P1B to Pqe.
A plurality of larger and smaller copper foil land portions 57 and 58, which do not function as a heater circuit pattern, but which are intended to reinforce the heater 174L, are respectively formed in the first and second heater regions 174a and 174b, as best shown by oblique lines drawn in Fig.29.
Bores 59 are defined at a plurality of points in each of the copper foil land portions 57 and 58 and adapted to be filled with a molten rubber at the winding of the heater 174L around the inner piece assembly 33 to ensure a reliable adhesion of the heater 174 to the inner piece assembly 33.
The formation of the copper foil land portions 57 ensures that regions having different dispersed densities of the copper foil 55 are formed in the first and second heater circuit pattern portions P1$ and PZH in the circumferential direction of the heater 174 wound around the inner piece assembly 33, and higher-density regions 174a1 and 174a3 are formed in the first heater region 174a on opposite sides of a lower-density region 174a2 located in the middle in the circumferential direction .
The formation of the copper foil land portions 58 ensures that regions having different dispersed densities of the copper foil 55 are formed in the third and fourth heater circuit pattern portions P3B and P4B in the circumferential direction of the ~ ° 59 heater 174 wound around the inner piece assembly 33, and higher-density regions 174b1 and 174b3 are formed in the second heater region 174b on opposite sides of a lower-density region 174b2 located in the middle in the circumferential direction.
In this way, the density of the copper foil 55 dispersed~s varied in the circumferential direction of the heater 174 wound around the inner piece assembly 33 due to the formation of the copper land portions .57 and 58. However, the disposition of the higher-density regions 174a1, 174a~, 174b1 and 174b3 and the lower-density regions 174a2 and 174bz, i.e., the disposition of the copper foil land portions 57 and 58 may be determined depending upon the distribution of a pressure of contact of a left hand with the left grip 27L2.
A pair of connecting lands 61 and 62 are formed in the connecting region 174c by exposure of the copper foil 55. One 61 of the connecting lands is connected to the first heater circuit pattern portion P1B by a connecting portion 63 disposed near the connecting region 174c, and the other connecting land 62 is connected to the third heater circuit pattern portion PCB
by a connecting portion 64 disposed near the connecting region 174c. The first and third heater circuit pattern portions PlB
and P3B are connected to each other by a connecting portion 65 adjoining the connecting portion 64. Moreover, each of the connecting portions 63, 64 and 65 is formed relatively widely, so that a wasteful heat is not generated.
Elongated bores 66 , 66 corresponding to the openings 47 , 47 in the inner piece assembly 33 are defined in the heater 174 between the first and second heater regions 174a and 174b. The elongated bores 66, 66 are formed larger than the openings 47, 47 , so that the openings 47 , 47 cannot be occluded by the heater 174L even if the relative positions of the inner piece assembly 33 and the heater 174L are misaligned slightly from each other.
A band-shaped copper foil-non-formed region 67 is formed in the heater 174 in such a manner to connect the elongated bores 66 , -66 to each other. The flexibility of the heater 174 is enhanced by the copper foil-non-formed region 67.
Such heater 174L is wound around the outer periphery of the inner piece assembly 33 in such a manner that the connecting region 174c extends toward the annular portion 36 at the circumferential central portion of the first inner piece 331, and the heater 174 is positioned relative to the inner piece assembly 33 by bringing a pair of positioning pins 68 protruding from the outer periphery of the first inner piece 331 at locations near the annular portion 36 into engagement into positioning pins 69, 69 provided in the connecting lands 61 and 62 in the heater 34.
Connecting wires 73 and 74 led from a cord 72 are connected .. at soldering portions 75 and 76 to the connecting lands 61 and 62 of the heater 174L wound around the inner piece assembly 33.
The cord 72 and the connecting wires 73 and 74 are mounted in a mounting groove 70 over a range of approximately 270 degree in the annular portion 36 and led outwards through a cord ' 61 supporting portion 71, as shown by an arrow 77 in Fig.28. A
cylindrical portion 78 for guiding and supporting the led-out portion of the cord supporting portion 71 is projectingly provided on the flange 32 of the grip body 35.
Such left grip 272 is mounted at the left end of the steering handlebar 26 in such a manner that the cylindrical portion 78 , i . a . , the cord 72 , is led out in a direction declined forwards, for example, at 60 degree in a direction of movement of the motorcycle, as shown in Fig.24. Thus, in the heater 174 installed in the left grip 27L2, the first heater region 174a is disposed in an obliquely upper range A of approximately 180 degree on the front in the direction of movement of the motorcycle, i.e., at the front portion of the left grip 27~z.
Referring to Fig.30, the right grip 2782 is mounted at a throttle pipe 79 which is turnably mounted at the right end of the steering handlebar 26. The right grip 2782 is mounted at the throttle pipe 79 in such a manner that the cylindrical portion 78 , i . a . , the cord 72 , is led out in a direction sloped up forwards, for example, at 60 degree in the direction of movement of the motorcycle. Thus, in the heater 1748 installed in the right grip 2782, the first heater region 174a is disposed in an obliquely lower range A' of approximately 180 degree on the front in the direction of movement of the motorcycle, i.e. , at the front portion of the right grip 27RZ.
With the third embodiment, the heaters 174 and 1748 are embedded in the left and right grips 27L2 and 2782, respectively, in such a manner that the first heater region 174a is disposed in the grip body 35 on the front side in the direction of movement of the motorcycle, while the second heater region 174b is disposed in the grip body 35 on the rear side in the direction of movement of the motorcycle. Moreover, the density of the copper foil 55 dispersed throughout the first and second heater circuit pattern portions P1g and PZB formed in the first heater region 174a is higher than the density of the copper foil 55 dispersed throughout the third and fourth heater circuit pattern portions P3H and P,H formed in the second heater region 174b. Thus, the front portion of the grip body 35 in the direction of movement of the motorcycle is a portion touched by fingertips of a hand grasping each of the grips 27~z and 2782.
By the fact that the density of the copper foil 55 dispersed in the front portion of the grip body 35 is higher than that in the rear portion of the grip body 35, as described above, the fingertips sensitively perceiving the cold can effectively be warmed, while warming the entire grip 272, 2782 by the copper foil 55 dispersed over the substantially entire periphery of the grip.27L2, 2782, thereby providing an excellent warm-feeling with a relatively reduced amount of power consumed.
In the first and second heater regions 174a and 174b in each of the heaters 174L and 1748, the density of the copper foil 55 dispersed in the first and third heater circuit pattern portions P1B and P3B disposed at the locations adjacent the flange 32 of each of the grips 272 and 2782, i.e. , at the inner end of.grip body 35 is higher than the density of the copper foil 55 dispersed in the second and fourth heater circuit pattern portions P2B and P4B disposed at the location spaced apart from the flange 32 of each of the grips 272 and 2782, i.e. , at the outer end of grip body 35 . Thus , the inner end of the grip body 35 is a portion relatively strongly touched by a hand when grasping each of the grips 27L2 and 2782. By the fact that the density of the copper foil 55 dispersed in this portion is larger than that at the outer end, the hand can effectively be warmed.
Thus, an excellent warm-feeling can be provided with a relatively reduced amount of power consumed.
Moreover, the left and right grips 27L2 and 2782 are only slightlj different in shapes of their inner surfaces.
Therefore, the density of the copper foil 55 dispersed at the front portion of the grip body 35 can be set higher than that at the rear portion only by leading-out of the cords 72 in different directions, and the number of parts and the manufacture cost can be reduced by the fact that most of the arrangement of one of the grips 272 and 2782 is the same as most of the arrangement of the other grip.
In each of the heaters 174 and 1748, the density of the copper foil 55 dispersed is ununiform, but in a state in which the grips 27L2 and 2782 are not grasped, the grips 272 and 2782 are uniformly warmed by heat transfer. Therefore, when the grips 272 and 2782 has been grasped after heating of the heaters 174 and 1748 by supplying the power, the sense of incompatibility due to the ununiformity of the temperature cannot be felt.
Fig.31 illustrates a fourth embodiment of the present invention, wherein portions or components corresponding to those in each of the above-described embodiments are designated by like reference characters.
In place of the heaters 1741, and 1748 in the third embodiment , a heater 184 corresponding to a substantially half of a periphery of each of the grips 27L2 and 2782 may be integrally embedded in the grip body 35 of each of the left and right grips 272 and 2782. This heater 184 is constructed as an FPC heater and formed in correspondence to the first inner piece 331 which is substantially half of the periphery of the inner piece assembly 33 . Namely, the heater 184 is formed in correspondence to the first heater region 174a of each of the heaters 174L and 1748 in the third embodiment.
First and second heater circuit pattern portions P1~ and Pzc having different densities of the copper foil 55 dispersed are formed in the heater 184 by a strip pattern of the copper foil 55. When the grips 27L2 and 2782 have been mounted on the steering handlebar 26 and the throttle pipe 79 , the density of the copper foil 55 dispersed in the first heater circuit pattern portion P1~ located on the inner side in the widthwise direction of the motorcycle, i.e., at the inner end of the grip body 35 is set higher than that in the second heater circuit pattern portion Pz~ located on the outer side in the widthwise direction, . - 65 i.e.., at the outer end of the grip body 35.
A plurality of large and small copper foil land portions 57 which do not function as a heater circuit pattern, but which are intended to reinforce the heater 184, are formed in the heater 184 , as clearly shown by oblique lines drawn in Fig. 31 .
The formation of the copper foil land portions 57 ensures that higher-density regions 1841 and 1843 are formed in the first and second heater circuit pattern portions P1~ and P2~ on opposite sides. of a lower-density region 1842 located at the middle in the circumferential direction of the heater 184 integrally embedded in the grip body 35. The disposition of the higher-density regions 1841 and 1843 and the lower-density region 1842, i.e., the disposition of the copper foil land portions 57 is determined depending upon the distribution of a pressure of contact of a hand with each of the grips 272 and 2782 (see the third embodiment).
With the fourth embodiment, when the grips 27L2 and 2782 are mounted on the steering handlebar 26 and the throttle pipe 79, the heaters 184 are disposed in the ranges shown by A and A' in Figs . 24 and 30 , i . a . , on the front side in the direction of movement of the motorcycle. Thus, fingertips sensitively feeling the cold can be effectively warmed, thereby providing an excellent warm-feeling with a relatively reduced amount of power consumed. In addition, by the fact that the density of copper foil 55 dispersed in the first heater circuit pattern portion P1~ disposed at the inner end of the grip body 35 is set higher than that in the second heater circuit pattern portion P2~ disposed at the outer end of the grip body 35 , the hand can be effectively warmed, thereby also providing an excellent warm-feeling with a relatively reduced amount of power consumed.
. Fig.32 illustrates a fifth embodiment of the present invention. A substantially semi-cylindrical inner piece 173 made of a synthetic resin and having a heater 184 wound around an outer periphery thereof is integrally embedded in a grip body 35 mounted at an end of the steering handlebar 26.
The inner piece 173 is formed so that the wall thickness of its circumferential central portion is larger than that of its circumferentialiy.opposite ends. Sandwiched between an inner periphery of the heater 184 and an outer periphery of the inner piece 173 are a sheet 176 made of an aluminum foil and located on the side of the heater 184, and a heat insulating material 177 located on the side of the inner piece 173.
The heat insulating material 177 is comprised of, for example, VHB acrylfoam which is a trade name and is available from Sumitomo 3M, Co . , Ltd . , or the like . The heat insulating material 177 is bonded to an outer surface of the semi-cylindrical inner piece 173 by a pressure sensitive adhesive double coated tape or the like. The sheet 176 is also bonded to an outer surface of the heat insulating material 177 by a pressure sensitive adhesive double coated tape or the like, and the heater 184 is bonded to an outer surface of the sheet 177.

70488-120D '-By the fact that the sheet 176 and the heat insulating material 177 are mounted between the heater 184 and the inner piece 173 in the above manner, a heat generated in the heater 184 can be inhibited to the utmost from being escaped toward the steering handlebar 26. More specifically, when the heater 184 has been wound directly around the inner piece~173, the rising of the temperature of the grip surface is late due to the escaping of the heat toward the steering handlebar 26 and moreover, the highest temperature is relatively low, as. shown by a curve A in Fig.33. On the contrast, due to the addition of the heat insulating material 177, the escaping of the heat to the steering handlebar 26 can be reduced, as shown by a curve B in Fig . 33 , whereby the rising of the temperature of the grip surface can be hastened and moreover, the highest temperature can be also relatively increased. Further, due to the addition of the sheet 176 made of the aluminum foil, the rising of the temperature of the grip surface can further be hastened by heat reflection, as shown by a curve C in Fig.33, and the distribution of the temperature of the grip surface can further be uniformized by the heat transfer.
In the fifth embodiment, the sheet 176 and the heat insulating material 177 are mounted between the heater 184 and the inner piece 173, but the structure may be such that either one of the sheet 176 and the heat insulating material 177 is mounted between the heater 184 and the inner piece 173. In addition, the fifth embodiment has been described with regard to the structure in which the semi-cylindrical inner piece 173 is embedded in the grip body 35, but it is of course that the arrangement of the fifth embodiment is applicable to a structure in which heaters 34~, 34R, 174, 1748 are wound around an inner piece assembly 33 cylindrically formed of a pair of semi-. cylindrical inner pieces 331 and 332.
Figs . 34 to 36 illustrate a sixth embodiment of the present invention. Fig.34 is a plan view of a right grip in a buggy vehicle; Fig.35 is a sectional view taken along.a line 35-35 in Fig.34; and Fig.36 is a plan view similar to Fig.34, but in a state in which a grip has been removed from a steering handlebar.
A grip 27 is mounted at a right end of a steering handlebar 26 in a buggy vehicle. A mounting member 178 is mounted on substantially half of a periphery of the steering handlebar 26 inside the grip 27, and a case 179 mounted to a remaining half of the periphery of the steering handlebar 26 is fastened to the mounting member 178 by a pair of screw members 180, 180.
Moreover, a throttle lever 181 capable of being operated by a right hand grasping the grip 27 is turnably supported on the case 179 to extend toward the grip 27.
w The grip 27 is comprised of an inner piece assembly 33 which has, for example, a heater 34R or 1748 wound around an outer periphery thereof and which is integrally embedded in a grip body 35. A flat notch 36a for enabling the turning operation of the throttle lever 181 is provided in an annular portion 36 which is provided at an axially inner end of the grip 27.
In a structure of the right end of the steering handlebar 26 of such buggy vehicle, when the grip 27 is turned about an axis of the steering handlebar 26 , the turning of the throttle lever 181 may be difficult in some cases due to catching of the throttle lever 181 in the notch 36a. Therefore, in order to . inhibit the turning of the grip 27 about the axis of the steering handlebar 26, a limiting member 182 is integrally coupled to the mounting member 178 by welding or the like.
The limiting member 182 is formed into an arcuate shape in cross section to come into close contact with the outer surface of the steering handlebar 26. A plurality of fitting claws 182a, 182a are integrally formed at a tip end of the limiting member 182 and adapted to be fitted into between a plurality of support projections 42a, 42a which are formed at circumferential distances on an inner peripheral surface of the grip 27. Moreover, the distance between the support projections 42a, 42a is not uniform and is set to be different depending upon the circumferential point of the grip 27. The width of the fitting claws 182a, 182a is set in correspondence to such distance.
With the sixth embodiment , by the fact that the mounting member 178 is fixed to the steering handlebar 26 and that the plurality of fitting claws 182a, 182a included in the limiting member 182 integrally coupled to the mounting member 178 are fitted between the plurality of support projections 42a, 42a around the inner periphery of the grip 27, the turning of the grip 27 about the axis of the steering handlebar 26 is reliably inhibited. Thus, even if the grip 27 is strongly grasped by a right hand, the grip 27 cannot be turned, and the smooth operation of the throttle lever 181 can be ensured.
Although the embodiments of the present invention have been described. in detail , it will be. understood that the present invention is not limited to the above-described embodiments, and various modifications in design may be made without departing from the spirit and scope of the invention defined in claims.
For example, the present invention is applicable to a structure in which a nichrome wire is used as a heat generating element in place of the copper foil.
Industrial Applicability The heater-installed grip for the vehicle, the control device for the heater installed in the vehicle grip and the electrical connection structure for the heater unit for the grip in the vehicle according to the present invention can be suitably used for the grip in a vehicle such as a motorcycle, a snowmobile, a buggy vehicle and the like.

Claims

1. A control device for a heater installed in a grip for a vehicle, comprising a switching means (106) for ON/OFF-controlling a power supplied from a battery (90) to a heater (34L, 34L; 174L, 174R; 184) installed is a grip (27L1, 27R1; 27L2, 27R2; 27) mounted on a steering handlebar (26), and a driving-signal outputting means (103) for outputting a driving signal for turning the switching means (106) ON, characterised in that said control device further includes a battery voltage monitoring means (104) which is operable to provide a state to prohibit the outputting of the driving signal from said driving-signal outputting means (103), when a voltage corresponding to a power source voltage outputted from said battery (90) is smaller than a first voltage threshold value, and to provide a state to permit the outputting of the driving signal from the driving-signal outputting means (103), when the voltage corresponding to said power source voltage is equal to or larger than a second voltage threshold value set higher than said first voltage threshold value by a predetermined value or more, said first voltage threshold value being set as being (V M - .DELTA.V1 + .DELTA.V2), wherein V M represents a necessary minimum power source voltage required in said battery (90); .DELTA.V1 represents a decrement of voltage dropped from said battery (90) to said battery voltage monitoring means (104); and .DELTA.V2 represents a maximum voltage detection error on the plus side presumed in said battery voltage monitoring means (104).

2. A control device ae claimed in claim 1, further comprising a periodic voltage generating means (100) for generating a periodic voltage whose value is periodically varied, a comparative voltage outputting means (101) for outputting a predetermined comparative voltage depending upon a temperature regulating operation for the heater (34L, 34R; 174L, 174R; 184), a rectangular-wave signal outputting means (103) for outputting a rectangular-waves signal having a duty ratio depending upon said temperature regulating operation by comparing the periodic voltage outputted from said periodic voltage generating means (100) with the comparative voltage outputted from said comparative voltage outputting means (101), wherein said switching means (106) is for ON/OFF-controlling the power supplied from the battery (90) to said heater (34L, 34R; 174L, 174R; 184) in response to the rectangular-wave signal outputted from said rectangular-waves signal outputting means (103).

3. A control device as claimed in claim 2, therein the battery voltage monitoring means (104) are adapted to monitor a power source voltage outputted from the battery (90), so that when the power source voltage is dropped down to a value lower than a predetermined value, a rectangular-wave signal indicative of command to control said switching means (106) into an OFF state is forcibly outputted from said rectangular-wave signal outputting means (103) by maintaining said power source voltage at the predetermined value.

4. A control device as claimed in either one of claims 2 and 3, further including a fail-safe means (102) operable to ensure that when the comparative voltages outputted from the comparative voltage outputting means (101) becomes irregular, a rectangular-wave signal indicative of command to control the switching means (106) into an OFF
state is forcibly outputted from said rectangular-wave signal outputting means (130) by maintaining said comparative voltage at a predetermined value.

5, A control device as claimed is either one of claims 3 and 4, further including a constant-voltage outputting means (99) for outputting a predetermined constant voltage (Vc) based on a voltage supplied from the battery (90), wherein the battery voltage monitoring means (104) monitors the voltage output from the battery (90) by comparing voltages at input and output sides of the constant-voltage outputting means (99) with each other.

6. A control device as claimed is either one of claims 3 and 4, wherein said rectangular-wave signal outputting means (103) includes as operational amplifier (124) having an input terminal to which as output signal from said battery voltage monitoring means (104) is directly inputted.

7. A control device as claimed is any one of claims 2, 3 or 4, wherein when a triangular wave voltage outputting from the periodic voltage generating means (100) is lower than a comparative voltage (Vp) outputted from a comparative voltage outputting means (101), said rectangular-wave signal outputting means (103) outputs a driving signal (V OUT) of a high level to bring said heater (34L, 34R; 174L, 174R; 184) into an ON state.

8. A control device for a heater installed in a grip for a vehicle as claimed in any one of claims 1 to 7, which is installed in a control box (138) on which a knob (140) for performing a temperature regulating operation of the heater (34L, 34R; 174L, 174R; 184) is disposed.

9. A system for a vehicle having a heater-installed grip, the system comprising s grip having a heater and a control device as claimed in claim 1, said grip further comprising substantially semi-cylindrical inner pieces (33 2, 33 2, 173) of a synthetic resin which have a planar heater (34L, 34R; 174L, 174R; 184) wound around an outer periphery thereof and which are integrally embedded in a cylindrical grip body (35) of a rubber assembled to a pipe-shaped steering handlebar (26) or a throttle pipe (79), wherein a circumferentially central portion of each of the inner pieces (33 1, 33 2, 173) is formed with a wall thickness larger than those of circumferentially opposite ends thereof.

10. A system for a vehicle having a heater-installed grip, the system comprising a grip having a heater and a control device as claimed in claim 1, and further comprising substantially semi-cylindrical inner pieces (33 1 and 33 2) of a synthetic resin which have a planar heater (34L, 34R; 174L, 174R; 184) wound around an outer periphery thereof and which are integrally embedded in a cylindrical grip body (35) of a rubber assembled to a pipe-shaped steering handlebar (26) or a throttle pipe (79), wherein grooves (43, 44) arcuate in cross section, into which a molten rubber flows in the formative of the grip body (35), are defined in inner peripheral surfaces of the inner pieces (33 1 and 33 2).

11. A system for a vehicle having a heater-installed grip, the system comprising a grip having a heater and a control device ae claimed in claim 1, and further comprising substantially semi-cylindrical inner pieces (33 1 and 33 2) of a synthetic resin which have a planar heater (34L, 34R; 174L, 174R; 184) round around an outer periphery thereof and which are integrally embedded in a cylindrical grip body (35) of a rubber assembled to a pipe-shaped steering handlebar (36) or a throttle pipe (79), wherein as axially extending projection (33a) is formed at a circumferentially central portion of an inner surface of each of said inner pieces (33 2 and 33 2).

12. A system as claimed in claim 11, wherein grooves (43, 44), which are arcuate in cross section and into which a molten rubber flows is the formation of the grip body (35), are formed in a lattice-shaped fashion in regions of inner surfaces of said inner pieces (33 1, 33 2), other than regions where said projection (33a) is formed.

l3. A system for a vehicle having a heater-installed grip, the system comprising a grip having a heater and a control device as claimed in claim 1, and further comprising a substantially semi-cylindrical inner piece (33 1) of a synthetic resin which has a planar heater (34L, 34R; 174L, 174R; 184) wound around an outer periphery thereof and which is integrally embedded in a cylindrical grip body (35) of a rubber assembled to a pipe-shaped steering handlebar (26) or a throttle pipe (79) , wherein said inner piece (33 1) is integrally provided, at axially predetermined locations thereon, with annular portions (36, 37) which are intended to prevent the deformation of the inner piece (33 1) attendant on the shrinkage of a rubber layer after formation of the grip body (35) , and each of which functions as a guide for insertion of the steering handlebar or the throttle pipe.

14. A system as claimed in claim 13, wherein said annular portions (36, 37) are provided in an opposed relation to axially opposite ends of said inner piece (33 1, 33 2).

15. A system as claimed in claim 14, wherein a cylindrical inner piece assembly (33) is comprised of the first inner piece (33 1) which has the annular portions (36, 37) formed at axially opposite ends thereof and which is formed into a substantially semi-cylindrical shape, and the second inner piece (33 2) which is formed into a substantially semi-cylindrical shape from a synthetic resin and disposed between said annular portions (36, 37).

16. A system as claimed is claim 15, wherein circumferentially central portions of the axially opposite ends of said second inner piece (33 2) engage with said annular portions (36, 37) in a recess/projection manner.

17. A system as claimed in either one of claims 15 and 16, wherein openings (48, 49), which permit a molten rubber to flow into said inner places (33 1, 33 2) in a process for forming the grip body (35), are provided at least either between said inner pieces (33 1, 33 2), or between said second piece (33 2) and both said annular portions (36, 37).

18. A system as claimed in claim 14, wherein one of said annular portions (36, 37) has a plurality of positioning abutment projections (50) provided on an inner peripheral surface thereof for abutment against an outer surface of a core die (82) in a process for forming the grip body (35) to align axes.

19. A system as claimed in claim 14, wherein either one (36) of said annular portions (36, 37) has a plurality of positioning notches (51) provided in an inner peripheral surface at one end thereof for engagement with the core die (82) in a process for forming the grip body (35) to determine a circumferential position of the inner piece (33 1) relative to a grip body forming mold.

20. A system as claimed in claim 14, wherein either one (37) of said annular portions (36, 37) has a positioning projection (52) provided thereon for abutment against a grip body forming mold in a process for forming the grip body (35) to determine an axial position of said inner piece (33 1), so that a molten rubber can flow into said inner piece (33 1) on opposite sides of said positioning projection (52).

21. A system for a vehicle having a heater-installed grip, the system comprising a grip having a heater and a control device as claimed in claim 1, and further comprising a heat generating element (55) integrally embedded in substantially an entire periphery of a grip body (35) made of a rubber, wherein said heat generating element (55) is disposed in a dispersed manner in the grip body (35) in such a manner that the density of the heat generating element dispersed at a front portion of said grip body in the direction of movement of the vehicle is higher than that at a rear portion of said grip body.

22. A system for a vehicle having a heater-installed grip, the system comprising a grip having a heater and a control device as claimed in claim 1, and further comprising a heat generating element (55) integrally embedded in substantially an entire periphery of a grip body (35) made of a rubber, wherein said heat generating element (35) is disposed in a dispersed manner in said grip body (35) in such a manner that the density of said heat generating element (55) dispersed at an end portion of said grip body (35) located on an inner side when assembled on said vehicle, is higher than that at an opposite end portion of said grip body (35) located on an outer side when assembled on said vehicle.

23. A system for a vehicle having a heater-installed grip, the system comprising a grip having a heater and a control device as claimed in claim 1, and further comprising a heat generating element (55) integrally embedded in substantially half of a periphery of a grip body (35) made of a rubber, wherein said heat generating element (55) is disposed in the grip body (35) at a portion located at the front of said grip body (55) in a direction of movement of the vehicle when assembled on the vehicle.

24. A system for a vehicle having a heater-installed grip, the system comprising a grip having a heater and a control device as claimed in claim 1, and further comprising a heat generating element (55) integrally embedded in substantially half of a periphery in a grip body (35) made of a rubber, wherein said heat generating element (55) is disposed is a dispersed manner in said grip body (35) in such a manner that the density of said heat generating element (55) dispersed at an end portion of said grip body (35) located on an inner side when assembled on the vehicle is higher than that at an opposite end portion of said grip body (35) located on an outer side when assembled on the vehicle.

25. A system for a vehicle having a heater-installed grip, the system comprising a grip having a heater and a control device as claimed in claim 1, the system further comprising an electrical connection structure for a heater unit, the heater unit comprising the heater and the control device, the grip being mounted on a steering handlebar (26) of the vehicle in use, and wherein in use plus-side and minus-side connecting Wires (94, 95) led out of said heater unit (92) for the grip are interruptively connected to a plus wire of one of first and second electric parts of the vehicle (158; 23L, 23R) and to a minus wire of the other electric part at locations near said electric parts (158, 23L, 23R) which are disposed on said steering handlebar (26) or a member 21) turned in unison with said steering handlebar (26) and to which a power is supplied from the battery (90) in use.

26. A system as claimed in claim 25, wherein in use one of said plus-side and minus-side connecting wires (94, 95) is interruptively connected between a main switch (142) for switching-over the connection and disconnection with said battery (90) and a stop switch (158) disposed on the steering handlebar (26), and the other of said plus-side and minus-side connecting wires (94, 95) is interruptively connected to between said battery (90) and left and right front winker lamps (23L, 23R) disposed on the steering handlebar (26) or the member (21) turned in unison with said steering handlebar (26).

27. ~A system for a vehicle having a heater-installed grip, the system comprising a grip having a heater and a control device as claimed in claim 1, the system further comprising an electrical connection structure for a heater unit, the heater unit comprising the heater and the control device, the grip being mounted on a steering handlebar (26) of the vehicle in use, and wherein in use an earth wire (147) connected to a grounding portion (E c) of said battery (90) is coupled to the steering handlebar (26) or a member (21) which is turned in unison with the steering handlebar (26), wherein in use a first connecting wire (94) led out of said heater unit (92) for the grip is interruptively connected between the battery (90) and an electric part of the vehicle (158) at a location near said electric part (158) which is disposed on the steering handlebar (26) or the member (21) turned in unison with the steering handlebar (26) and to which an electric power is supplied from the battery (90) in use, and a second connecting wire (95) led out of said heater unit (92) for the grip is connected in use to said steering handlebar (26) or said member (21) turned in unison with the steering handlebar (26).