CA1206021A - Variable speed driving mechanism - Google Patents
Variable speed driving mechanismInfo
- Publication number
- CA1206021A CA1206021A CA000430322A CA430322A CA1206021A CA 1206021 A CA1206021 A CA 1206021A CA 000430322 A CA000430322 A CA 000430322A CA 430322 A CA430322 A CA 430322A CA 1206021 A CA1206021 A CA 1206021A
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- Canada
- Prior art keywords
- friction wheel
- wheel
- bearing assembly
- driven shaft
- shaft
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Abstract
VARIABLE SPEED DRIVING MECHANISM
Abstract of the Disclosure A variable speed mechanism in which a friction wheel is movable in a plane normal to the plane of a driving wheel and in frictional engagement therewith to obtain a driving of the friction wheel at a speed and in a direction dependent upon the location of the frictional engagement of the friction wheel with the driving wheel, the driving wheel being rotated about a non-rotating pintle which engages the rim of the friction wheel when located at the axis of the driving wheel.
Abstract of the Disclosure A variable speed mechanism in which a friction wheel is movable in a plane normal to the plane of a driving wheel and in frictional engagement therewith to obtain a driving of the friction wheel at a speed and in a direction dependent upon the location of the frictional engagement of the friction wheel with the driving wheel, the driving wheel being rotated about a non-rotating pintle which engages the rim of the friction wheel when located at the axis of the driving wheel.
Description
~2~P6~
V~RIABLE SPEED DRIV]:NG MECHANISM
Field 'I'o Which Invention Relates 1 My invention relates to a driving mechanism in which a variable speed is obtained by the periphery of a friction wheel frictionally engaging the flat face of a driving wheel to rotate the friction wheel upon rotation of the driving wheel~ the plane of the friction wheel being normal to the plane of the driving wheel, the speed and direction of rotation of the friction wheel being dependent upon the distance of the location of the r c-tion wheel from th~ axis of the driving wheel and the side of the location of the friction wheel rela-tive to the axis of the d~iving wheel. The invention is usefulfor utilization in the driving mechanism in power-driven applian~es of various kinds such as powered snow-throwers, and is here described in association with a snow-thrower by way of example .
Background Art Of The Invention The related art background is ~enerally known to the Applicant as those prior variable speed driving mechanisns in which variable driving speed is derived from the combination of a flat sided driving wheel frictionall~ engaged by a friction wheel disposed in a plane normal to the flat side of the driving wheel, the speed and direction of rotation of the friction wheel being dependent upon the location of the frictional engage-ment of the friction wheel with the flat side of the driving wheel relative to the axis of the driving wheel.
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Statement Of The Invention It is an object of the invention to provide that upon alignment of the plane of the friction wheel substantially with the axis of the driving wheel, the friction wheel is out of frictional engagement with the driving wheel to assure non-rotation of the friction wheel upon rotation of the driving wheelO
A further object of the invention is to assure non-rotation of a friction wheel upon movement of the friction wheelto selected locations relative to the axis of a driving wheel engageable by the friction wheel.
1 A further object is the provision of a unique and efficient mechanism for the driving of a driven part of an appliance, such ~s the supporting wheels of a snow thrower, whereby the driven part, such as said wheels, may be rotated at a speed and in a location dependen~ upon the location of a friction wheel relative to an engine driven driving wheel.
Another object is to assure that a friction wheel engageable with a driving wheel is not ro~ated upon selected positioning of the friction wheel relative to the axis of said driving wheel, to better control the operation of parts driven by the friction wheel.
Other objects and ad~antayes may be observed from the following description o the invention in conjunction with the several drawings.
Fi~ures Of The Drawings FIGU~ 1 is a vertical sectional view of a snQw thrower housing containing a pre~erred form of my variable speed driving mechanism taken through the line 1-1 of FIGU~ 2~ the parts b~ing shown in clutching engagement;
FIGURE 2 is a horizontal sectional view of the snow throw-er housing shown in FIGURE 1, the pl~ne o the sectional view in FIGURE 2 heing normal to the sectional view in ~IGUR~ 1, the parts being shown in clutched engagement;
FIGURE 3 is a view somewhat simil~r to that of FIGU~E 1, with some portions omittPd for purposes of clarity of illustra-tion, the parts in the view being shown in un-clutchea engage-ment; ~nd FIGURE 4 is a detailed plan view of ~he portion of my mechanism used in shifting the carriage that changes the loca-tion of the friction wheel of my mechanism relative to the axis of the driving wheel~
The invention is shown in conjunction wi~h a snow thrower for which it is particularly adapted for driving the wheels of the snow thrower in a direction and at a speed sele~ted as desired. The housing of the snow thrower,illustrated by way of example, is denoted by the re~erence character 11. Protruding 6~
1 upwardly from the housing 11, as seen in FIGURE 1, is a housing extension llA.
One of the two wheels of the snow thrower to be driven by my mechanism is indicated by the reference character 12.
A like wheel on the opposite side of the snow thrower in axial alignment with, and mounted on the same axle, is not shown.
Extending from an engine or motor such as an internal combustion engine or an electric motor mounted on the snow thrower, but not shown, i5 an engine-driven shat 13 which supplies the energy for the snow thrower. Non-rotatably mounted on the free end of shaft 13 is a pulley 14. A pulley 15 spaced from, and below, the pulley 14, is operatively connected by sh~ft 13 to the auger or snow impeller of the snow thrower.
A belt 16 is reeved around pulleys 14-and 15 and is held in appropriate tension by an icller pulley 17. In this manner the auger or impeller of the snow thrower is powered by the engine through shaft 13, pulley 14~ belt 16, pulley 15, and shaft 18.
Carried by the housing 11 on. a rod 21 extending between the sides of the housing 11 is a p~late ox supporting structure 19 disposed in a generally upright. manner. The mountin~ of the plate 19 on rod 21 is such tha.t the plat~ 19 m~y pivotally be tilted on the axis of rod 21 be~tween khe position shown in FIGU~ES 1 and 2 and the position shown in FIGURE 3.
The plate 19 may be manually tilted by the operator of the snow thrower by means o~ a rod 55 connected at one of its ends to the plate 19 at a side of the pl~te 19 at a level ab~ve the rod 21. This rod extends along the outer side of the housing 11 and along its side as shown in FIGURE 2. The other end of rod 55 is connected by a lever arm 56 at a point intermediate of its ends. The lever arm 56 is pivotally connected by bolt 57 to the side of housing 11 to permit the lever arm 56 to swi.ng.
The outer or free end of lever arm 56 is connected to spring 58A and xod 58 which is manipulated by the operator of the snow thrower from a position at the outer free ends o~ the handles 25 ~only one of which is shown) extending rearwardly from the hs:msi.ng 11.
- ~ -1 A coil spring 54 has one of its ends connected to lever arm 56 and the other end to side wall of housing 11 to bias lever arm 56 downwardly and hence~ by way of rod 55, to tilt plate 19 forwardly. The operator upon pulling upwardly on spring 58A and rod 58 overcomes the bias of spring 54 and thus swings the plate 19 to tilt rearwardly to its position shown in FIGURES 1 and 2~
Firmly secured to plate 19 so as not to rotat~ on its own axis is a pintle member 22 which in the form shown is a bolt. This pintle member has a flat end surface 22A which in the form sho~m is the end flat surface of the bolt 22~ A
nut 23 on the forward end of bolt 22 firmly holds the b~lt to plate 19 in a manner to prevent rotation of bolt 22 on its axis.
Mounted on the bolt 22 is a bearing assembly 24 of usual construction which permits the outer race of the assembly 24 to fxeely re~olve around the bolt 22. ~ me~al d~ivlng wheel 20 is mounted on the assembly 24 so that the driving wheel may freely revolve on the bolt 22. The driving wheel being carried by plat0 19 swinys forwardly and rearwardly upon the tilting of the plate 19 between the position shown in FIGUR~S 1 and 2 and its position shown in FIGURE 3.
The driving wheel 2~ has a grooved periphery so as to form a pulley. A belt 27 is reeved around the pulley formed by driving wheel 20 and a pulley 26 non-rotatively secured to the shaft 13 extending from the engine, not shown. An idler pull~y 28 ~laintains required tension on the belt 27 and thus provides that driving wheel 20 is revolved by the pulley 26 and shaft 13.
The rearward side face of driving wheel 20 is flat to provide a flat side 20A extending in a plane across the driving wheel from edge to edge. This flat face 20A is interrupted adjacent the axis of the driving wheel 20 so as to accommodate the head of bolt 22. There is sufficient space between the head of the bolt and the driving wheel 2~ at the flat side 22A
so as to assure that the driving wheel may reely rotate on its axis without interference with the bolt head. The flat end 1 surface 22A of the bolt head is slightly protruded from the plane of the flat side 20A of the driving wheel.
A fxiction wheel 29 is non-rotatably mounted on stub shaft 30 in a manner that.rotation of the friction wheel rotates the stub shaft 30 on its axis. The perlpheral edge or border of the friction wheel 29 is provided with a rim 29A, firmly secured thereto, which rim 29A is made of a rubber or rubber-like material which imparts a friction characteristic theretoJ
that is, the rim 29A resists sliding and slipping when in tight engagement with another surface.
When the plate 19 is moved backward (by means of rod 55, lever arm 5~, spring 58A and rod 58) the driving wheel 20 is carried backward with it to the position shown in FIG~RES 1 and 2. This presses the flat side 20A, of metal driving wheel 20 back lS tightl.y against the outer surface of rim ~9A of friction wheel 29. The coil spring 54 pulling down on lever axm 56 aids in urging the clriving wheel 20 againr,t the rim 29A when the tension of spriny 58A on rod 58 is ~elaxed by the operator to allow the spring 54 to exert its biasing ~orce.
The stub sha~t 30 is carried by a bearing assembly that allows the stub shaft 30 and ~r.icltion wheel 29 to freely rotate relative to the outer race of bearing assembly 31 The outer race or shell of the bearing assembly 31 is firmly secured to, and is carried by a plat~ 32 extendin~ lonyitudinally of the housing 11. ~he other or rearward end of supporting plate 3 2 i5 secured to the outer shell of a barrel-like cylindrical supporting membex 33.
This cylindrical supporting member 33 contains an inner sleeve or bearing 34 having two axially aligned parts extending into and held within the membe.r 33. The inner surface of member 33 is cylindxical and the outer surface of sleeve or bearing 34 is cylindrical and complementing the inner surface of member 33 whereby the sleeve or bearing 34 may freely rotate within and relative to the member 33.
The inner surface of bearing or sleeve 34 is non-cylindrical and in the form shown this inner surface has a hexagonal cross-sectional shape. The inner surface of this bearing or sleeve 34 3~Q~
1 complements the outer surface of the driven shaft 35 having a hexagonal cross-section. The fit between the driven shaft 35 and bearing or sleeve 34 is such that the shaft 35 may freely rotate on its axis within the bearing or sleeve 34 t and is also such that the supporting member 33 and slee~e 34 held within the supporting member 33 may freely slide longitudinally along the shaft 35.
The outer ends of driven shaft 35 are round or cylindri-cal in cross section, and these outer ends are carried in bearin~, preferably ~lastic ~cyi~ndr~ a~ bearings, 36 and 37 mounted vn the opposite side walls of housing 11.
Secured to the sleeve or bearing 34 at an end of member 33 and slidable along the shaft 35 with the member 33 and sleeve 34 is a gear ~3 which is thus non-rotatively carried whereby rotation of gear 43 rotates the shaft 35. The gear 43 is slidable along the shaft 3~ with the member 33 and inner sleeve or bearing 34 while maintaining non-rotative engagement of gear 43 with shaft 35.
A gear ~4 is non-rotatively mounted on the stub shaft 30 at its end opposite to the ~riction wheel 29, whereby r~tation of shaft 30 by friction wheel 29 rotates the gear 4~. A chain 4$ reeved about, and enmeshed with, gears 44 and 43 provides that friction wheel 29, through shaft 30, gear 44, chain 45, and gear 43 rotates the driven shaft 35 on its axis.
Non-rotatively mounted on the driven hexagonal shaft 35, at its end closest to bearing 36, is a gear 38 so that rotation of shaft 35 rotates gear 38. A gear 40 is non-rotatively mount~d on the axle 41 which carries the wheels 12 (only one of which is shownj on the opposite sides of the snow thrower.
The wheels, non-rotatively carried by axle 41, are rotated, and thus the snow thrower is driven along a path~ by rotation of the axle 41 and year 40 through the chain 39 and gear 38 upon the rotation of sha~t 35 on its axis.
A shifting bar or plate 46, spaced from and disposed parallel to, the supporting plate 32, is secured to both the bearing assembly 31 and the member or barrel 33. Both the shaft 30 and sh~ft 35 may rotate on their respective axes ~6'[~
1 relative to the plate member 32 and shifting bar 46. The plate 3~ and shifting bar together provide a carriage for supporting the bearing assembly 31 and the stub shaft and friction wheel 29 carried by the bearing assembly 31. The forward free end of shifting member 46 is notched and this notched end is supported on a rod 47 extending between and mounted to the opposite sides of the housing 11. The shifting member is slidable alony the rod laterally of the snow thrower.
A pin or stud 48 in the form illustrated is welded to the rearward end portion of shifting member 46 and extends therefrom to protrude as a finger rearwardiy and downwardly at an incline from a horizontal plane thrsugh the shifting bar 46.
The rearward-most end of the pin 48 i5 headed or enlargea as illustrated. Movement of the pin 48 causes corresponding movement of the shifting bar 46 laterally o~ the snow thrower, that i9 along the shaft 35.
An actuating plate o~ member 49 of a generaly triangular shape shown in FIGU~E q is pivotally mounted by means of a pivotal mounting 51 on a bracket 51A to a rear wall of the housing 11 and disposed within the housing. The actuating member 49 may swing in an arc on pivot mounting 51 in a plane parallel to the rear wall of the housing 11 to which it is mounted. The actuating m~mber 49 is provided with a notch or slot 50 extending in from its oute~ edge a~ ~ distance from the pivot mounting 51 as illustrated in FIGURE 4. This notch accommodates the shank of the pin or stud 48 extending out from the shifting bar 46. The head or enlargement on the free end of the pin or stud 48 is disposed on the rearward side of the actuating plate or member 49~
An actuating rod 52, extending back alongside the handles 25 of the snow ~hrower to within reach of the operator of the snow thrower, has its lower end connected by means of a pivot pin mountin~ 53 to ~he actuating plate or member 49. The connection of rod 52 to connection 53 is adjustable ky means of a threaded inter-fit between the connection 53 and rod 52.
Upon the actuating rod 52 being moved to where it is shown in full lines in FIGURE 4, then the actuating plate is 1 positioned to where it appears in full lines in FIGURE 4. At this location the pin or stud 48 is in the notch 50 and this 1 ocation is marked by khe letter 'IF" (for ~Iforward~) in FIGURE
4. Vpon the operator pulling the rod 52 the actuating plate is swung (and forward travel speed of the snow thrower is gradually decreased) until the actuating plate 49 has pivotally swung to where it is shown in broken lines and the notch 50 has moved the pin 48 to the location marked 'INll (for llneutral") in FIGURE 4 (and the driven travel of the snow thrower has ceased). Upon the operator pulling the rod 52 still more, then the actuating plate 49 is pivotally swung (and direction of the dri~en travel of the snow thrower is gradually reversed) until the actuating plate 49 has pivotally swung to where it is ~h.own .in broken lin~es and the notch 50 has moved the pin 48 to the lo-cation marked l'R" (for "reverse") in FIGURE 4.
The Gperat.ion Of' The'Mechanism Upon spring 58A and the rod 5~ being moved upwardly by theoperator to t.ilt the lever arm S6 upwardly the plate or supporting structure 19, by means of xod 55, i.s tilted up and rearwardly to the position shown in FIGURES 1 ancl 2. This puts the mechanism in clutched condition, that is the driving wheel 20 rotat~a by the engine is put into driving engagement with the rim ~9A of the friction wh~el 29 as shown in FIGURES 1 and 2. By reason of the friction or non-sliding characteristics of the material of rim 29A engaging the flat side 20A of steel driving wheel 20, rotation of the wheel causes the friction wheel 29 to rotate.
Through the shafts~ gears, chains and connections heretofore described, the friction wheel 29 rotates the wheels 12 of the snow thrower at a speed and in a direction ~forward, neutral or rever.se)-which is dependent upon the locat.ion of the friction wheel 2g .relative to the axis of the driving wheel. Upon the actuating plate 49 ~eing swung to full forward position ~as shown in full 1ines in FIGURE 4) the friction wheel 29 is positioned by shifting bar 46 to its position shown in full lines i.n FIGURE 2. In this location of the :Eriction wheel 29, it is close to the circumferential boundary of the flat side 20A
;
: . ~
~2~
_9~
1 cf driving ~heel 20. This provides that the friction wheel is rotated at its maximum speed relative to the rotative speed of the driving wheel 20~
The mechanism is de-clutched by tilting the plate 19 forwaraly, by means of rod 55, lever ~r~ ~, spring 58A and rod 58,to where the flat side 22A is moved away from the friction wheel 29 and thus discontinues clriving of the described mechanism by the engine. No power is then delivered to the mechanism, and hence to the wheels 12 of the snow thrower~ by this de-clutched conditlon of the parts a~ illustrated in FIGUR~ 3 wherein the plate 19 is 5hown as tilted forwardly.
(In the herein discussion of speeds, it is to be under-stood that reference is not being made to absolute speeds but rather to speeds relative to the rota~ive speed of the driving wheel, which in turn depends on the speed of the engine on the snow thrower)~, Upon moving the friction wheel 23, by the shifting bar 46 and actua~ing plate ~9, toward the ,axis of the driving wheel 20, the rotative speed of the friction ~wheel decreases, which in turn decreases the rotative speed of the wheels 1~ of the snow thrower. Upon the riction wheel 29 being shifted by the shifting bar 46 and actuating plate 49 to a location, as shown in FIGURE 1, aligned with the axis of the driving wheel 20 the rim 29A is then in engagement with the end surface area 22A of the pintle 22, that is with the end surfac~ of the head of bolt 22 forming the pintle.
The pintle or bolt 22 does not rotat~ on its axis and so there is no driving rotation of the friction wheel 29 by the interengagement of the rim 29A with the end surface 22A.
3Q In this loc~tion of the friction whe~l 29~ khe driving mechanism is in neutral. The shafts, geaxs and chains of the mechanism are not moved and the wheels 12 of the snow thrower are not rotatively driven. The engagement of rim 29A with the stationary or non-rotating head of bol~ 22 assures clear neutrality and an absence of "hunting" or shifting between forward and rearward direction when the friction wheel is approximately at the axis of wheel 20. Furthermore, by this ~6~
1 arrangement of having the rim 29A enqagin~ a stationary sur-Eace when aligned with the axis of wheel 20, the material of rim 29A is protec-ted against being torn or stressed by fric-tional engagement tending to move the rim 29A in opposite directions, that is to move the rim 29A both in a forward and rearward direction. The shape, frictional characteristics, and condition of the rim 29A are retained and preserved over a longer period of time than would otherwise exist without this unique feature.
In FIGURE 2, the letter "F" indicates the location of the fric-tion wheel (shown in full lines) where maximum relatlve speed forwardly is obtained; the letter "N" indicates the location where the friction wheel would be (and where it is shown to be in FIGURE 1) where no speed and no direction of 15 drive is obtained (that is when -the mechanism i5 in "neutral");
and the let-ter "R" ind.icates the location of the friction wheel (shown in broken lines) where reverse direction o drive is obtained. Because it is usual a,nd desired to have reverse drive at a lower relative speed than for forward drives, the 20 ~ocation of the Eriction wheel at "R" is closer to the axis of the wheel 20 than is the location o the frlction wheel at "F" indica~ed in full lines in FIG~RE 2, as being closest to the outer periphery of wheel 20.
The locations of "F", "N" and "~" for the friction 25 wheel 29 in FIGURE 2 correspond to the locations of "Fl', "N"
and "R" for the actuating plate in FIGURE ~.
The mechanism described and shown provides an efficient and economical structure for obtaining a variable speed drive, shiftable between different directions, as described in connec-3Q tion with a snow thrower. It is also ap~reciable to otherdriven devices, such as tractors, agricultural tillers, mowers, and other a~pliances wherein its functions are useful.
While ~ have illustrated and described a preferred embodim~nt of my invention, it will be underst~od that -this 35 embodiment is by way of example only and not to be construed as limiting.
V~RIABLE SPEED DRIV]:NG MECHANISM
Field 'I'o Which Invention Relates 1 My invention relates to a driving mechanism in which a variable speed is obtained by the periphery of a friction wheel frictionally engaging the flat face of a driving wheel to rotate the friction wheel upon rotation of the driving wheel~ the plane of the friction wheel being normal to the plane of the driving wheel, the speed and direction of rotation of the friction wheel being dependent upon the distance of the location of the r c-tion wheel from th~ axis of the driving wheel and the side of the location of the friction wheel rela-tive to the axis of the d~iving wheel. The invention is usefulfor utilization in the driving mechanism in power-driven applian~es of various kinds such as powered snow-throwers, and is here described in association with a snow-thrower by way of example .
Background Art Of The Invention The related art background is ~enerally known to the Applicant as those prior variable speed driving mechanisns in which variable driving speed is derived from the combination of a flat sided driving wheel frictionall~ engaged by a friction wheel disposed in a plane normal to the flat side of the driving wheel, the speed and direction of rotation of the friction wheel being dependent upon the location of the frictional engage-ment of the friction wheel with the flat side of the driving wheel relative to the axis of the driving wheel.
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Statement Of The Invention It is an object of the invention to provide that upon alignment of the plane of the friction wheel substantially with the axis of the driving wheel, the friction wheel is out of frictional engagement with the driving wheel to assure non-rotation of the friction wheel upon rotation of the driving wheelO
A further object of the invention is to assure non-rotation of a friction wheel upon movement of the friction wheelto selected locations relative to the axis of a driving wheel engageable by the friction wheel.
1 A further object is the provision of a unique and efficient mechanism for the driving of a driven part of an appliance, such ~s the supporting wheels of a snow thrower, whereby the driven part, such as said wheels, may be rotated at a speed and in a location dependen~ upon the location of a friction wheel relative to an engine driven driving wheel.
Another object is to assure that a friction wheel engageable with a driving wheel is not ro~ated upon selected positioning of the friction wheel relative to the axis of said driving wheel, to better control the operation of parts driven by the friction wheel.
Other objects and ad~antayes may be observed from the following description o the invention in conjunction with the several drawings.
Fi~ures Of The Drawings FIGU~ 1 is a vertical sectional view of a snQw thrower housing containing a pre~erred form of my variable speed driving mechanism taken through the line 1-1 of FIGU~ 2~ the parts b~ing shown in clutching engagement;
FIGURE 2 is a horizontal sectional view of the snow throw-er housing shown in FIGURE 1, the pl~ne o the sectional view in FIGURE 2 heing normal to the sectional view in ~IGUR~ 1, the parts being shown in clutched engagement;
FIGURE 3 is a view somewhat simil~r to that of FIGU~E 1, with some portions omittPd for purposes of clarity of illustra-tion, the parts in the view being shown in un-clutchea engage-ment; ~nd FIGURE 4 is a detailed plan view of ~he portion of my mechanism used in shifting the carriage that changes the loca-tion of the friction wheel of my mechanism relative to the axis of the driving wheel~
The invention is shown in conjunction wi~h a snow thrower for which it is particularly adapted for driving the wheels of the snow thrower in a direction and at a speed sele~ted as desired. The housing of the snow thrower,illustrated by way of example, is denoted by the re~erence character 11. Protruding 6~
1 upwardly from the housing 11, as seen in FIGURE 1, is a housing extension llA.
One of the two wheels of the snow thrower to be driven by my mechanism is indicated by the reference character 12.
A like wheel on the opposite side of the snow thrower in axial alignment with, and mounted on the same axle, is not shown.
Extending from an engine or motor such as an internal combustion engine or an electric motor mounted on the snow thrower, but not shown, i5 an engine-driven shat 13 which supplies the energy for the snow thrower. Non-rotatably mounted on the free end of shaft 13 is a pulley 14. A pulley 15 spaced from, and below, the pulley 14, is operatively connected by sh~ft 13 to the auger or snow impeller of the snow thrower.
A belt 16 is reeved around pulleys 14-and 15 and is held in appropriate tension by an icller pulley 17. In this manner the auger or impeller of the snow thrower is powered by the engine through shaft 13, pulley 14~ belt 16, pulley 15, and shaft 18.
Carried by the housing 11 on. a rod 21 extending between the sides of the housing 11 is a p~late ox supporting structure 19 disposed in a generally upright. manner. The mountin~ of the plate 19 on rod 21 is such tha.t the plat~ 19 m~y pivotally be tilted on the axis of rod 21 be~tween khe position shown in FIGU~ES 1 and 2 and the position shown in FIGURE 3.
The plate 19 may be manually tilted by the operator of the snow thrower by means o~ a rod 55 connected at one of its ends to the plate 19 at a side of the pl~te 19 at a level ab~ve the rod 21. This rod extends along the outer side of the housing 11 and along its side as shown in FIGURE 2. The other end of rod 55 is connected by a lever arm 56 at a point intermediate of its ends. The lever arm 56 is pivotally connected by bolt 57 to the side of housing 11 to permit the lever arm 56 to swi.ng.
The outer or free end of lever arm 56 is connected to spring 58A and xod 58 which is manipulated by the operator of the snow thrower from a position at the outer free ends o~ the handles 25 ~only one of which is shown) extending rearwardly from the hs:msi.ng 11.
- ~ -1 A coil spring 54 has one of its ends connected to lever arm 56 and the other end to side wall of housing 11 to bias lever arm 56 downwardly and hence~ by way of rod 55, to tilt plate 19 forwardly. The operator upon pulling upwardly on spring 58A and rod 58 overcomes the bias of spring 54 and thus swings the plate 19 to tilt rearwardly to its position shown in FIGURES 1 and 2~
Firmly secured to plate 19 so as not to rotat~ on its own axis is a pintle member 22 which in the form shown is a bolt. This pintle member has a flat end surface 22A which in the form sho~m is the end flat surface of the bolt 22~ A
nut 23 on the forward end of bolt 22 firmly holds the b~lt to plate 19 in a manner to prevent rotation of bolt 22 on its axis.
Mounted on the bolt 22 is a bearing assembly 24 of usual construction which permits the outer race of the assembly 24 to fxeely re~olve around the bolt 22. ~ me~al d~ivlng wheel 20 is mounted on the assembly 24 so that the driving wheel may freely revolve on the bolt 22. The driving wheel being carried by plat0 19 swinys forwardly and rearwardly upon the tilting of the plate 19 between the position shown in FIGUR~S 1 and 2 and its position shown in FIGURE 3.
The driving wheel 2~ has a grooved periphery so as to form a pulley. A belt 27 is reeved around the pulley formed by driving wheel 20 and a pulley 26 non-rotatively secured to the shaft 13 extending from the engine, not shown. An idler pull~y 28 ~laintains required tension on the belt 27 and thus provides that driving wheel 20 is revolved by the pulley 26 and shaft 13.
The rearward side face of driving wheel 20 is flat to provide a flat side 20A extending in a plane across the driving wheel from edge to edge. This flat face 20A is interrupted adjacent the axis of the driving wheel 20 so as to accommodate the head of bolt 22. There is sufficient space between the head of the bolt and the driving wheel 2~ at the flat side 22A
so as to assure that the driving wheel may reely rotate on its axis without interference with the bolt head. The flat end 1 surface 22A of the bolt head is slightly protruded from the plane of the flat side 20A of the driving wheel.
A fxiction wheel 29 is non-rotatably mounted on stub shaft 30 in a manner that.rotation of the friction wheel rotates the stub shaft 30 on its axis. The perlpheral edge or border of the friction wheel 29 is provided with a rim 29A, firmly secured thereto, which rim 29A is made of a rubber or rubber-like material which imparts a friction characteristic theretoJ
that is, the rim 29A resists sliding and slipping when in tight engagement with another surface.
When the plate 19 is moved backward (by means of rod 55, lever arm 5~, spring 58A and rod 58) the driving wheel 20 is carried backward with it to the position shown in FIG~RES 1 and 2. This presses the flat side 20A, of metal driving wheel 20 back lS tightl.y against the outer surface of rim ~9A of friction wheel 29. The coil spring 54 pulling down on lever axm 56 aids in urging the clriving wheel 20 againr,t the rim 29A when the tension of spriny 58A on rod 58 is ~elaxed by the operator to allow the spring 54 to exert its biasing ~orce.
The stub sha~t 30 is carried by a bearing assembly that allows the stub shaft 30 and ~r.icltion wheel 29 to freely rotate relative to the outer race of bearing assembly 31 The outer race or shell of the bearing assembly 31 is firmly secured to, and is carried by a plat~ 32 extendin~ lonyitudinally of the housing 11. ~he other or rearward end of supporting plate 3 2 i5 secured to the outer shell of a barrel-like cylindrical supporting membex 33.
This cylindrical supporting member 33 contains an inner sleeve or bearing 34 having two axially aligned parts extending into and held within the membe.r 33. The inner surface of member 33 is cylindxical and the outer surface of sleeve or bearing 34 is cylindrical and complementing the inner surface of member 33 whereby the sleeve or bearing 34 may freely rotate within and relative to the member 33.
The inner surface of bearing or sleeve 34 is non-cylindrical and in the form shown this inner surface has a hexagonal cross-sectional shape. The inner surface of this bearing or sleeve 34 3~Q~
1 complements the outer surface of the driven shaft 35 having a hexagonal cross-section. The fit between the driven shaft 35 and bearing or sleeve 34 is such that the shaft 35 may freely rotate on its axis within the bearing or sleeve 34 t and is also such that the supporting member 33 and slee~e 34 held within the supporting member 33 may freely slide longitudinally along the shaft 35.
The outer ends of driven shaft 35 are round or cylindri-cal in cross section, and these outer ends are carried in bearin~, preferably ~lastic ~cyi~ndr~ a~ bearings, 36 and 37 mounted vn the opposite side walls of housing 11.
Secured to the sleeve or bearing 34 at an end of member 33 and slidable along the shaft 35 with the member 33 and sleeve 34 is a gear ~3 which is thus non-rotatively carried whereby rotation of gear 43 rotates the shaft 35. The gear 43 is slidable along the shaft 3~ with the member 33 and inner sleeve or bearing 34 while maintaining non-rotative engagement of gear 43 with shaft 35.
A gear ~4 is non-rotatively mounted on the stub shaft 30 at its end opposite to the ~riction wheel 29, whereby r~tation of shaft 30 by friction wheel 29 rotates the gear 4~. A chain 4$ reeved about, and enmeshed with, gears 44 and 43 provides that friction wheel 29, through shaft 30, gear 44, chain 45, and gear 43 rotates the driven shaft 35 on its axis.
Non-rotatively mounted on the driven hexagonal shaft 35, at its end closest to bearing 36, is a gear 38 so that rotation of shaft 35 rotates gear 38. A gear 40 is non-rotatively mount~d on the axle 41 which carries the wheels 12 (only one of which is shownj on the opposite sides of the snow thrower.
The wheels, non-rotatively carried by axle 41, are rotated, and thus the snow thrower is driven along a path~ by rotation of the axle 41 and year 40 through the chain 39 and gear 38 upon the rotation of sha~t 35 on its axis.
A shifting bar or plate 46, spaced from and disposed parallel to, the supporting plate 32, is secured to both the bearing assembly 31 and the member or barrel 33. Both the shaft 30 and sh~ft 35 may rotate on their respective axes ~6'[~
1 relative to the plate member 32 and shifting bar 46. The plate 3~ and shifting bar together provide a carriage for supporting the bearing assembly 31 and the stub shaft and friction wheel 29 carried by the bearing assembly 31. The forward free end of shifting member 46 is notched and this notched end is supported on a rod 47 extending between and mounted to the opposite sides of the housing 11. The shifting member is slidable alony the rod laterally of the snow thrower.
A pin or stud 48 in the form illustrated is welded to the rearward end portion of shifting member 46 and extends therefrom to protrude as a finger rearwardiy and downwardly at an incline from a horizontal plane thrsugh the shifting bar 46.
The rearward-most end of the pin 48 i5 headed or enlargea as illustrated. Movement of the pin 48 causes corresponding movement of the shifting bar 46 laterally o~ the snow thrower, that i9 along the shaft 35.
An actuating plate o~ member 49 of a generaly triangular shape shown in FIGU~E q is pivotally mounted by means of a pivotal mounting 51 on a bracket 51A to a rear wall of the housing 11 and disposed within the housing. The actuating member 49 may swing in an arc on pivot mounting 51 in a plane parallel to the rear wall of the housing 11 to which it is mounted. The actuating m~mber 49 is provided with a notch or slot 50 extending in from its oute~ edge a~ ~ distance from the pivot mounting 51 as illustrated in FIGURE 4. This notch accommodates the shank of the pin or stud 48 extending out from the shifting bar 46. The head or enlargement on the free end of the pin or stud 48 is disposed on the rearward side of the actuating plate or member 49~
An actuating rod 52, extending back alongside the handles 25 of the snow ~hrower to within reach of the operator of the snow thrower, has its lower end connected by means of a pivot pin mountin~ 53 to ~he actuating plate or member 49. The connection of rod 52 to connection 53 is adjustable ky means of a threaded inter-fit between the connection 53 and rod 52.
Upon the actuating rod 52 being moved to where it is shown in full lines in FIGURE 4, then the actuating plate is 1 positioned to where it appears in full lines in FIGURE 4. At this location the pin or stud 48 is in the notch 50 and this 1 ocation is marked by khe letter 'IF" (for ~Iforward~) in FIGURE
4. Vpon the operator pulling the rod 52 the actuating plate is swung (and forward travel speed of the snow thrower is gradually decreased) until the actuating plate 49 has pivotally swung to where it is shown in broken lines and the notch 50 has moved the pin 48 to the location marked 'INll (for llneutral") in FIGURE 4 (and the driven travel of the snow thrower has ceased). Upon the operator pulling the rod 52 still more, then the actuating plate 49 is pivotally swung (and direction of the dri~en travel of the snow thrower is gradually reversed) until the actuating plate 49 has pivotally swung to where it is ~h.own .in broken lin~es and the notch 50 has moved the pin 48 to the lo-cation marked l'R" (for "reverse") in FIGURE 4.
The Gperat.ion Of' The'Mechanism Upon spring 58A and the rod 5~ being moved upwardly by theoperator to t.ilt the lever arm S6 upwardly the plate or supporting structure 19, by means of xod 55, i.s tilted up and rearwardly to the position shown in FIGURES 1 ancl 2. This puts the mechanism in clutched condition, that is the driving wheel 20 rotat~a by the engine is put into driving engagement with the rim ~9A of the friction wh~el 29 as shown in FIGURES 1 and 2. By reason of the friction or non-sliding characteristics of the material of rim 29A engaging the flat side 20A of steel driving wheel 20, rotation of the wheel causes the friction wheel 29 to rotate.
Through the shafts~ gears, chains and connections heretofore described, the friction wheel 29 rotates the wheels 12 of the snow thrower at a speed and in a direction ~forward, neutral or rever.se)-which is dependent upon the locat.ion of the friction wheel 2g .relative to the axis of the driving wheel. Upon the actuating plate 49 ~eing swung to full forward position ~as shown in full 1ines in FIGURE 4) the friction wheel 29 is positioned by shifting bar 46 to its position shown in full lines i.n FIGURE 2. In this location of the :Eriction wheel 29, it is close to the circumferential boundary of the flat side 20A
;
: . ~
~2~
_9~
1 cf driving ~heel 20. This provides that the friction wheel is rotated at its maximum speed relative to the rotative speed of the driving wheel 20~
The mechanism is de-clutched by tilting the plate 19 forwaraly, by means of rod 55, lever ~r~ ~, spring 58A and rod 58,to where the flat side 22A is moved away from the friction wheel 29 and thus discontinues clriving of the described mechanism by the engine. No power is then delivered to the mechanism, and hence to the wheels 12 of the snow thrower~ by this de-clutched conditlon of the parts a~ illustrated in FIGUR~ 3 wherein the plate 19 is 5hown as tilted forwardly.
(In the herein discussion of speeds, it is to be under-stood that reference is not being made to absolute speeds but rather to speeds relative to the rota~ive speed of the driving wheel, which in turn depends on the speed of the engine on the snow thrower)~, Upon moving the friction wheel 23, by the shifting bar 46 and actua~ing plate ~9, toward the ,axis of the driving wheel 20, the rotative speed of the friction ~wheel decreases, which in turn decreases the rotative speed of the wheels 1~ of the snow thrower. Upon the riction wheel 29 being shifted by the shifting bar 46 and actuating plate 49 to a location, as shown in FIGURE 1, aligned with the axis of the driving wheel 20 the rim 29A is then in engagement with the end surface area 22A of the pintle 22, that is with the end surfac~ of the head of bolt 22 forming the pintle.
The pintle or bolt 22 does not rotat~ on its axis and so there is no driving rotation of the friction wheel 29 by the interengagement of the rim 29A with the end surface 22A.
3Q In this loc~tion of the friction whe~l 29~ khe driving mechanism is in neutral. The shafts, geaxs and chains of the mechanism are not moved and the wheels 12 of the snow thrower are not rotatively driven. The engagement of rim 29A with the stationary or non-rotating head of bol~ 22 assures clear neutrality and an absence of "hunting" or shifting between forward and rearward direction when the friction wheel is approximately at the axis of wheel 20. Furthermore, by this ~6~
1 arrangement of having the rim 29A enqagin~ a stationary sur-Eace when aligned with the axis of wheel 20, the material of rim 29A is protec-ted against being torn or stressed by fric-tional engagement tending to move the rim 29A in opposite directions, that is to move the rim 29A both in a forward and rearward direction. The shape, frictional characteristics, and condition of the rim 29A are retained and preserved over a longer period of time than would otherwise exist without this unique feature.
In FIGURE 2, the letter "F" indicates the location of the fric-tion wheel (shown in full lines) where maximum relatlve speed forwardly is obtained; the letter "N" indicates the location where the friction wheel would be (and where it is shown to be in FIGURE 1) where no speed and no direction of 15 drive is obtained (that is when -the mechanism i5 in "neutral");
and the let-ter "R" ind.icates the location of the friction wheel (shown in broken lines) where reverse direction o drive is obtained. Because it is usual a,nd desired to have reverse drive at a lower relative speed than for forward drives, the 20 ~ocation of the Eriction wheel at "R" is closer to the axis of the wheel 20 than is the location o the frlction wheel at "F" indica~ed in full lines in FIG~RE 2, as being closest to the outer periphery of wheel 20.
The locations of "F", "N" and "~" for the friction 25 wheel 29 in FIGURE 2 correspond to the locations of "Fl', "N"
and "R" for the actuating plate in FIGURE ~.
The mechanism described and shown provides an efficient and economical structure for obtaining a variable speed drive, shiftable between different directions, as described in connec-3Q tion with a snow thrower. It is also ap~reciable to otherdriven devices, such as tractors, agricultural tillers, mowers, and other a~pliances wherein its functions are useful.
While ~ have illustrated and described a preferred embodim~nt of my invention, it will be underst~od that -this 35 embodiment is by way of example only and not to be construed as limiting.
Claims (3)
1. In a variable speed power transmission mechanism for delivering power from an engine to a working part, the mechanism having a driving wheel rotatable by the engine, a friction wheel engageable with the driving wheel to be driven in accordance with the then current location of the engagement of the friction wheel with the driving wheel, the friction wheel being carried on a shaft rotatable with the friction wheel, the working part being operatively connected to a driven shaft, to be rotated by the same, said driven shaft having a non-cylindrical outer surface, the improvement of a first bearing assembly rotatably carrying said friction wheel carrying shaft, a second bearing assembly having an inner part non-rotatively engaging said driven shaft and longitudinally slidable along said driven shaft and having an outer part concentrically mounted about said inner part to permit the inner part and said driven shaft to rotate within the said outer part, supporting means connected to both said first bearing assembly and the outer part of said second bearing assembly to support the same and to maintain their respective axes parallel to each other, driving connection means inter-connecting said friction wheel carrying shaft and said driven shaft to provide for rotation of the driven shaft by the friction wheel, shifting means connected to said support-ing means for shifting said supporting means along a path parallel to the axis of said first bearing assembly and said second bearing assembly, the shifting of said supporting means changing the location of the friction wheel relative to the axis of said driving wheel while maintaining the driving connection between said friction wheel carrying shaft and said driven shaft at varying shiftable positions of the first bearing assembly and second bearing assembly.
2. The improvement claimed in Claim 1 and in which the said driving connection means inter-connecting the friction wheel and the driven shaft comprises gears and an endless chain connecting the gears.
3. The improvement claimed in Claim 1 and in which said supporting means include an arm and in which the shift-ing means is operatively connected to said arm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000430322A CA1206021A (en) | 1983-06-14 | 1983-06-14 | Variable speed driving mechanism |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000430322A CA1206021A (en) | 1983-06-14 | 1983-06-14 | Variable speed driving mechanism |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1206021A true CA1206021A (en) | 1986-06-17 |
Family
ID=4125471
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000430322A Expired CA1206021A (en) | 1983-06-14 | 1983-06-14 | Variable speed driving mechanism |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1206021A (en) |
-
1983
- 1983-06-14 CA CA000430322A patent/CA1206021A/en not_active Expired
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| MKEX | Expiry |