CA1093038A

CA1093038A - Shock absorbing device

Info

Publication number: CA1093038A
Application number: CA259,440A
Authority: CA
Inventors: Kazuo Ikawa
Original assignee: Nissan Motor Co Ltd
Current assignee: Nissan Motor Co Ltd
Priority date: 1975-08-20
Filing date: 1976-08-19
Publication date: 1981-01-06
Also published as: JPS5248774A; AU1694576A; DE2637406A1

Abstract

ABSTRACT OF THE DISCLOSURE
The invention provides a safety belt system comprising a seat belt proper, a strap of plastically deformable material connected at its one end to the seat belt proper, and a flat base member formed with parallel slots through which the strap is interlaced, the width of the strap is gradually decreased from the one end thereof, to which the seat belt proper is connected, toward a free end thereof.

Description

1093C)38 'l'he present invention relates to a shock absorb-ing device and particularly to an apparatus for damping large forces within a short distance and dissipating large amounts of kinetic energy within a short time.
More specifically, the present invention is concerned with a shock absorbing device suitable for various parts or portions of a motor vehicle for minimizing damage on the vehicle due to collision, and thereby ensuring safety of the driver and or passengers of the vehicle.
In case of collision of the motor vehicle with an obstacle, there exists a great danger to the vehicle passengers by the impact force causing the driver to be thrown forwardly against the steering wheel and also causing the passengers against some interior parts of the vehicle~ Thus, it is desirable to provide impact absorbing means to parts and/or portions of the vehicle so as to eliminate or at least mitigate such danger.
Up to now, there have been proposed a number of shock absorbing devices which a~e used for the various parts and portions of the motor vehicle, such as for a bumper mechanism, a seat belt system, a steering system, a knee protecting system and a head protecting system in ; an instrument panel.
However, each of these shock absorbing devices has not been widely used for the parts and/or portions of ' ~'.

the véhicle by reason of -~heir complicated construc-tions. More spec.i.fically speaking, one shock absorbing devicc which is dcsi~.~ned t-o he 5Ui. ~able for an impact ahsorbing s~eering system .is no1 1~secl i.n a safe~y seat bclt sys1-cm. ~ach of l-hese devi.ces h;ns }.)eerl l~rocluced or manufactured so as ~o specifical]y suit t,he on].y one pu:rpose thereof. This causes a high cost of 1he safcty system.
Therefore, it is a mai.n object of the present invent;,on to provide an improved shock absorbing device which can be widely used in various kinds of safety systems of a motor vehicle.
It is another object of the present invention to provide a multi~purpose shock absorbing device whi,ch can be produced economically and is simple in construction.
It is still another object of the present invent.ion to provi.de a saf~y ,seat hclt system which ha~ t,he.rein an improved shock absorbing device.
It is a further object of the present invention to provide an impact absorbing steering system equipped with an improved shock absorbing device.

According to the present invention there is provided ,a safety seat belt system for protecting a passenger of a motor vehicle during rapid deceleration of the vehicle, comprising:
a seat belt proper for embracing the passenger; a strap member , connected at its one end to one end of said seat belt proper, said strap member being made of plastically deformable material;
the width of the strap member being gradually decreased from the one end thereof, to which the seat belt proper is connected, toward a free end thereof; and a flat base member formed therein with a plurality of parallelly arranged elongate slots, every adjacent two ofwhich define therebetweena respectivebridge portion,the fl.at base member being tightly but swingably connected at one end thereof to a relatively stationary portion of said vehicle, .

.~ -3-said sl,rap mem}ier being interlaced thro~gh said elongate slots of sai.d base mernber so that when an impact shock j.s applied to .said .~3eat be],t proper by a passenger upon rapid deceleration, ~e ;1 rap Inernber :i.S .successi,vely p1.asti,cally deformed as it is ~'o~:ced to sli,de bel-wecn and ovcr said respective bri~ye portions.
'l'he invention will now be dcscribed in more detail, by way of c~amp]e only, with reference to the accompanying drawinys, in which:
Fig. 1 shows several embodiments of a shock absorbing device according to the present invention, each schematically illustrating the novel concept of the present invention;
Fig. 2 is a schematically illustrated plan view of a safety seat belt system incorporating the shock absorbing dev,ice of the present invention;
Fig. 3 is a sect:.ional view taken along the line I-I of Fig. 2;

.

1093(~38 Fig. 4 is a s~hematically illustrative perspective view of an impact absorbing steering system incorporating the shock ahsorb;ng dcv;ce of the prcsent invention; and Fiy. 5 is a longitudinally sectioncd view of the illul;~ration of Fiy. 4.
~eferring now to Fig. 1 of the drawings, there are il]ustrated five variations a to e of a shock absorbing device _ of the present invention. Each of the variations a to e generally comprises a first or base member 12 which is fixed to a relatively stationary member or portion, though not shown.
At least two elongate or rod members 14 are firmly fixed to the base member 12 while beiny spaced apart from and in parallel to each other as shown. Alternately passing over or interlaced hetween the rod members 14 is a strap member 16 which is made of pJastically deform~ble material. The strap rncmber 16 has one end 16a loose and the other end 16b connected to a relatively movable member 18.
With the above-stated construction, the shock absorbing device _ will operate as follows:
When an impact force is applied to the relatively movable member 18 from the direction indicated by the arrow A, the plastically deformable s~rap member 16 is driven away from the base men~er 12. During the movement, ~093038 the strap member 16 will be successively plastically deformed at its contacting portions with the rod member ].4. The successive plastical de~ormations of the strap member 16 will absorb or weaken the impact shock. In reality, an elastic deformation of the strap member 16 will occur and a frictional resistance will form between the contacting surfaces of the strap member 16 and the rod members 14 during the movement of the strap member 16. Fortunately, the elastic deformation and frictional resistance are useful, but at a low rate, for absorbing the shock.
As stated above, the shock absorbing device 10 has a very simple construction, thus, it is very easy to control the shock absorbing capability of it. In con-nection with the determination of the shock absorbing capability of the subject device 10, there exist fol-lowing several parameters:
1) cross sectional form of the rod member 14;

2) cross sectional area of the rod member 14;
. 20 3) number of the rod members 14;
4) surface roughness of the rod member 14 and that . of the strap member 16;
5) thickness and width of the strap member 16;
6) distance between the rod members 14;
7) mutual arrangement of the rod members 14 and ~093(~38 ~he strap Inember 16; and 8) l)hysical property of ~he strap member 16. By choos:irlc3 one or more of t,he parameters 1 -to 8, various shock sor~iny de~vices having various shock a~sorbing capabilities respect,ively wi],l be readily Inade without emp]oying any other speci,fically desic;nated members.
Fi~s. 2 and 3 show an exemplary application of the subject shock absorbing device 10 to a safety seat belt system 17 of the motor vehic]e. In this figure, one end of a seat belt proper and a D-ring fastened to the end of the seat belt are respectively designated by reference numerals 20 and 22. A
strap 24 which is made of plastically deformable material and acts as the strap member 16 of Fig. 1 is connected at its one end to the D-ring 22 by means of a fastener 26. The width of the strap 24 is ~radually deoreased in the direction from one end thereof, to which the D-ring 22 is connected, to a free end thereof. As well shown in Fig. 3, the strap 24 is interlaced through parallel slots 28 formed in a base 30 which acts as the first or base member of Fig. 1. Bridges 32 located between the neighbouring two slots 28 act as the rod members 14 in the case of Fig. 1. The base 30 is tightly but swingably connected through a bolt 34 to a relatively stationary member such as the vehicle floor (not shown).
With this construction of the saiety seat belt I
, 30 ~, -7-system 17, the impact shock applied to the seat belt proper 20, by a passenger, upon a vehicle collision i5 absorbed or at least weakened by the shock absorbing device 10.
Figs. 4 and 5 show another exemplary application of the subject shock absorbing device 10 to a safety steering system 36. The safety steering system 36 in which the subject shock absorbing device 10 is used com-prises a hollow outer housing 38 which is firmly fixed to the vehicle body by means of a bracket 40. Tele-scopically received within the housing 38 is a tubular inner shaft 42 which consists of a large diameter portion 43 and a small diameter portion 44 as shown.
First and second ball bearings 46 and 48 are engaged between the inner shaft 42 and the outer housing 38 at the large and small diameter portions 43 and 44 re-spectively, thus allowing the tubular inner shaft 42 to rotate with respect to the outer housing 38. Along the inner cylindrical surface of the small diameter portion is formed a suitable number of longitudinally extending grooves (not shown). The end of the large diameter portion 43 of the inner shaft 42 is suitably coupled through a steering linkage 50 to the front wheels (not shown) of the vehicle. Within the small diameter portion 44 of the inner shaft 42 is disposed , ' .

~093038 an end or head portion 52 of a stub shaft 54 which is connected at its other end portion to a steering wheel 56 shown in phantom in Fig. 5, so that the vehicle may be steered by turning the steering wheel 56. The head portion 52 is formed at its cylindrical surface with a suitable number of longitudinally extending projections ~not shown) which will be engaged with the grooves of the small diameter portion 44 of the inner shaft 42 for thus allowing the head portion 52 and accordingly the stub shaft 54 to longitudinally move with respect to the inner shaft 42. A box shaped cover 58 having a square eross section portion 60 and a eylindrical portion 62 is 8paeedly mounted around the stub shaft 54 so that the portion 60 eovers the outside of the outer housing 38. A braeket 64 whieh is made of plastie is used for conneeting the eover 58 to the body of the vehicle. The reason why such plastic bracket is employed in this case will beeome clear later. Between the stub shaft 54 and the cylindrical portion 62 of the box shaped eover 58 is engaged a third ball bearing 66 which has inner and outer raees ~no numerals) firmly eonneeted to the stub shaft 54 and the cover 58, re-speetively. Preferably, the eonneetions between the third ball bearing 66 and the stub shaft 54, and between ;~25 the third ball bearing 66 and the tubular eover 58 may _ g _ ~ ' .

, ~093038 be made by welding. For the purpose of obtaining a balanced operation of the shock absorbing device 10, the safety steering system 36 in this case is equipped with two shock absorbing devices 10. Each of the devices 10 is arranged between the square cross section portion 60 of the cover 58 and the outside portion of the outer casing 38 and comprises elongate or rod members 68 which are spaced from each other and firmly connected at their both ends to the outer housing 38, and a strap 70 which alternately passed through the clearances defined between the rod members 68 and is firmly fastened at its one end to the tubular cover 58.
In a collision of the vehicle, the impact shock applied to the steering wheel 56 by the vehicle driver cause8 destruction of the plastic bracket 64. Then, the plastically deformable straps 70 are driven away from the rod members 68 connected to the outer housing 38 due to the forward movement of the cover 58. During the forward movement of the straps 70, the straps are saccessively plastically deformed in a manner mentioned before, so as to absorb the impact shock. Consequently, the vehicle driver is safe under such collision.
Although, in the previous description, only one ~ : strap is passed over the rod members in each of the `; 25 shock absorbing devices, it is also possible to use -- 10 -- ' ` . .

, . ~ .

a piled strap member consisting of at least two straps ovcrlapping each other for each of the devices. In this case, there will also be generated sliding friction at the contacting surfaces of the two straps during the extracting movement of the strap member from the rod members. This sliding friction is also useful for damping the impact shock.

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A safety seat belt system for protecting a passen-ger of a motor vehicle during rapid deceleration of the vehicle, comprising: a seat belt proper for embracing the passenger; a strap member connected at its one end to one end of said seat belt proper, said strap member being made of plastically deformable material, the width of said strap member being gradually decreased from the one end thereof, to which said seat belt proper is connected, toward a free end thereof; and a flat base member formed therein with a plurality of parallely arranged elongate slots every adajcent two of which define therebetween a respective bridge portion, said flat base member being tightly but swingably connected at one end thereof to a relatively stationary portion of said vehicle, said strap member being interlaced through said elongate slots of said base member so that when an impact shock is applied to said seat belt proper by a passenger upon rapid deceleration, said strap member is successively plastically deformed as it is forced to slide between and over said respective bridge portions.

2. A safety seat belt system as claimed in Claim 1, further comprising a D-ring through which said strap member and the end of the said seat belt proper are connected.

3. A safety seat belt system for protecting a passenger of a motor vehicle during rapid deceleration of the vehicle, comprising: a seat belt proper for embracing the passenger; an elongate flat strap member connected at its longitudinal one end to one end of said seat belt proper through a fastening member, said strap member being made of plastically deformable material, the width of said strap member being gradually decreased from the one end thereof, to which said seat belt proper is connected, toward a free end thereof; and a flat base member having therein a plurality of parallelly arranged elongate slots formed therein to define a plurality of parallelly arranged elongate bridge portions between the corresponding adjacent slots, said base member being tightly nut swingably connected at its one end to a stationary portion of said vehicle, said strap member being interlaced through said elongate slots of said base member so that when an impact shock is applied to said seat belt proper by a passenger upon rapid deceleration, the strap member is successively plastically deformed as it is forced to slide between and over said bridge portions.

4. A safety seat belt system as claimed in Claim 3, in which said fastening member is a D-ring.

5. A safety seat belt system as claimed in Claim 3, in which each of said bridge portions is formed to have a uniform cross section throughout the whole length thereof.