AU673789B2 - Pad for a steering wheel - Google Patents

Description

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION NAME OF APPLICANT(S): Toyoda Gosei Co., Ltd.

ADDRESS FOR SERVICE: DAVIES COLLISON CAVE Patent Attorneys 1 Littlu Collins Street, Melbourne, 3000.

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r o INVENTION TITLE: Pad for a steering wheel The following statement is a full description of this invention, including the best method of performing it known to me/us:- BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pad for an automotive steering wheel. This pad is composed of an insert designed to maintain the original shape of the pad, and a cover adapted to cover the insert and made of a flexible material.

2. Description of the Prior Art A conventional pad is mounted on the center of a steering wheel and covers the end surface of a cover which in .ooo turn, extends around a rear spoke core of the steering wheel.

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"This type of pad typically includes an insert, and a pad cover for covering the insert. The insert is made of a rigid synthetic resin so as to maintain the original shape of oooee S the pad. The cover is made of a flexible synthetic resin ooooo: (see Japanese laid-open utility model publication No. 3- 64154).

When a shock load is applied to the front part of the pad from forwarly and upwardly of the pad, the outer peripheral edge of the pad tends to be brought into contact with the end surface of the steering wheel cover. As this occurs, the amount of the shock load increases during -2deformation of the pad.

To this end, the entire pad could be made of a fle'.ble material. This may decrease the amount of the shock load applied to the pad, but deteriorates the original shape of the pad.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the foregoing problem and to provide a pad for a steering wheel, which is capable of reducing the amount of a shock load applied to the front part of the pad from forwardly and upwardly of the pad while maintaining its original shape.

In accordance with the present invention, there is provided a pad for a steering wheel, 15 comprising an insert adapted to maintain the shape of the pad, and a pad cover adapted to cover said insert and made of a flexible material, said pad being mounted centrally on said steering wheel and adapted to abut an end surface of a steering wheel cover, said steering wheel cover extending around a spoke core of the steering wheel, wherein said insert includes a substantially inverted U-shaped section adapted to cover part 20 of said spoke core of said steering wheel, and said section includes a recess extending along the circumference of said spoke core.

Preferably, the insert includes a top wall, covering the center of said steering wheel, and a side wall extending laterally and downwardly from said top wall, and a second recess is formed between said top wall and said side wall and extends laterally of said insert.

Preferably, an energy absorbing body may be located below and covered by the pad.

C 1 p:\pdocs\map\spcci\1782800.16a -jl3w When a shock load is applied to the front part of the pad from forwardly and upwardly of the pad, the outer peripheral edge of the pad tends to be brought into contact with the end surface of the cover which extends around the rear spoke core. According to the present invention, the substantially inverted U-shaped sleeve of the pad insert includes a bore or recess which extends along the circumference of the spoke core. This bore is narrowed to prevent an increase in the amount of the shock load when the pad is deformed.

The pad preferably has two layers, the insert adapted to maintain the original shape of the pad, and the cover for covering the insert. The insert is effective to maintain the shape of the pad when no shock load is applied thereto.

Thus, the pad can maintain its original shape and reduces the amount of a shock load when it is applied to the front part of the pad from forwardly and upwardly of the pad.

The second bore or aperture is laterally formed between the top wall and the rear side wall of th. pad insert. The first bore is first narrowed when the pad is deformed as a shock loaa is applied to the front part of the pad from forwardly and upwardly of the pad. Thereafter, the second bore is narrowed to further reduce the amount of the shock So: 20 load applied to the pad.

The energy absorbing body is preferably located below the pad. This energy absorbing body is deformed so as to absorb the shock load after the pad has been deformed. As such, the steering wheel as a whole may effectively absorb the shock load.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention will now be described, by way of example, with reference to the accompanying drawings, in which: p:\wpdocs\map\speci\1782800.16a -4- Fig. 1 is a plan view of a steering wheel with a pad according to one embodiment of the present invention; Fig.2 is a schematic sectional view showing the central portion of the steering wheel shown in Fig. 1; Fig. 3 is a plan view of the steering wheel shown in Fig. 1, with the pad and an energy absorbing body removed for clarity; Fig. 4 is a sectional view taken on the line IV-IV of Fig. 6; Fig. 5 is a sectional view taken on the line V-V of Fig. 6; Fig. 6 is a bottom plan view of the pad mounted the energy absorbing body; 0 0s 0 0 0** A N p:\\vpdocs\map\speci\1782800.16a Fig. 7 is a bottom plan view of an insert of the pad; Fig. 8 is a partial sectional view of the pad insert before the pad is deformed; Fig. 9 is a partial sectional view of the pad insert after the pad has been deformed; Fig. 10 is a partial sectional view showing the manner in which the top and rear side walls of the insert are deformed; and Fig. 11 is a partial sectional view of a pad according to another embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS S"Preferred embodiments of the present invention will now be described with reference to the accompanying drawings.

However, the present invention is not limited to those specific embodiments. It is intended for the invention to embrace various modifications and equivalents that fall .eoeei within the scope of the invention as defined by the appended claims.

Referring to Figs. 1 to 3, a steering wheel W comprises an annular ring section R, a boss section B, and four spoke sections S. The boss section B is positioned at the center of the ring section R. The spoke sections S each provide a connection between the ring section R and the boss section B. The ring section R has a core i. The spoke section S also has a core 3 connected to the core i. The core 1 and a part of the core 3 adjacent to the ring section R are surrounded by a cover 4 which is made from urethane foam. The ring section R and the spoke sections S form a steering wheel body M. This steering wheel body M, a pad 22, and an energy absorbing body 7 jointly form the steering wheel W.

The boss section B has a core 2 which is composed of a boss 2a and a plate 2b. The boss or hub 2a is connected to a steering shaft (not shown). The plate 2b is connected to the boss 2a and the spoke cores 3. A plurality of tongues 2c extend from the outer peripheral edge of the plate 2b so S as to hold the energy absorbing body 7 which will be S described later. Also, a bracket 2d extend from the outer eooo peripheral edge of the plate 2b. The energy absorbing body 7 is secured to the bracket 2d by bolts 18. The reference S numeral 5 designates a lower cover adapted to cover the bottom of the boss core 2. The lower cover 5 is secured to the boss core 2 by bolts 6.

The pad 22 is disposed above the boss section B.

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The pad 22 is positioned to cover the end surface of the cover 4 which in turn, extends along the circumference of each spoke core 3. The energy absorbing body 7 is disposed between the pad 22 and the boss core 2 and made from a metal sheet.

As shown in Figs. 2, and 4 to 6, the energy 6 absorbing body 7 includes an upper plate 8, a pair of front bent legs 9, 9, a pair of rear bent legs 10, 10, and a base plate 11. The upper plate 8 is positioned in the upper part of the energy absorbing body 7 and is substantially U-shaped as viewed in plan. The front bent legs 9, 9 extend downwardly from opposite front ends of the upper plate 8.

The rear bent legs 10, 10 extend inwardly and downwardly from opposite rear ends of the upper plate 8. The base plate 11 extends between the lower ends of the rear bent legs The upper plate 8 includes four contacts 8a (at a location corresponding to through holes 24b of a pad insert 23 which will be described later). Also, a pair of mounting holes 8b are formed in opposite rear ends of the upper plate 8 and have internal threads. The upper plate 8 further includes four apertures 8c through which the circumferential walls of recesses 24a (which are formed in the pad insert 23 a*e as will be described later) passes.

Each of the front bent legs 9, 9 has a bracket 9a.

The bracket 9a extends forwardly from the lower portion of the front bent leg 9. A clip 9c is secured to the lower end of the front bent leg 9 and has a substantially U-shaped section. As shown in Figs. 4 and 6, each bracket 9a has a mounting hole 9b through which a bolt 19 passes. The mounting holes 9b, 9b thus allow the insert 23 of the pad 22 to be secured to the energy absorbing body 7 by the bolts 19.

As shown in Fig. 2, each clip 9c is shaped to tightly fit over the tongue 2c of the boss core 2. Each clip 9c thus allows the energy absorbing body 7 with the pad 22 to be secured to the boss core 2.

The base plate 11 includes a substantially inverted U-shaped bracket lla. The bracket lla has a mounting hole llb through which a bolt 18 passes so as to secure the bracket lla to a bracket 2d of the boss core 2. This allows the energy absorbing body 7 together with the pad 22 to be secured to the boss core 2.

In the illustrated embodiment, the upper plate 8 of the energy absorbing body 7 forms part of a horn switch mechanism 13. The upper plate 8, which is connected to the eoc S boss core 2 through the front and rear bent legs, 9, 10, and the base plate 11 with the bracket lla, is connected to the cathode of a horn actuating circuit.

Reference will now be made to the horn switch mechanism 13. The horn switch mechanism 13 is composed of *S0**S S the upper plate 8 and a contact plate 14. The upper plate 8 is connected to the cathode of the horn actuating circuit.

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The contact plate 14 is substantially rectangular in shape and is mounted above the upper plate 8. The contact plate 14 is connected to the anode of the horn actuating circuit. A coil spring 15 is disposed in each of the four recesses 24a of the pad insert 23 so as to urge the contact plate 14 upwards. The pad insert 23 is provided with a plurality of 8 locking legs 24c so as to allow for downward movement of, but limit upward movement of the contact plate 14. The contact plate 14 has contacts 14a corresponding to the contacts 8a of the upper plate 8. The contact plate 14 also has a tongu, 14b. A lead 16 has one end connected to the tongue 14b and the other end connected to the anode of the horn actuating circuit.

The pad 22 is composed of the insert 23 and a cover 36. The insert 23 is made of a rigid synthetic resin such as polypropylene. The cover 36 is made of a flexible synthetic resin such as flexible vinyl chloride.

As shown in Figs. i, 2 and 7, the insert 23 includes a top wall 24, four sleeves 25 to 28, and four side walls 29 to 32. The top wall 24 of the insert is generally S flat. Each of the sleeves 25 to 28 has a substantially inverted U-shape in section. Each sleeve extends from the S" top wall 24 toward the spoke section S and is shaped to surround part of the spoke core 3. The side walls 29 to 32 each depend from the outer peripheral edge of the top wall 24.

o00eo0 The top wall 24 of the insert includes four recesses 24a at suitable positions to receive the 0*e corresponding coil springs 15. The top wall 24 also has four through holes 24b so that the contacts 8a of the upper plate 8 face with the corresponding contacts 14a of the contact plate 14. The four locking legs 24c of the top wall 24 are engaged with the outer peripheral edge of the contact plate 9 14. Two mounting holes 24d are formed in the rear end of the top wall 24. Two bolts 20 pass through the corresponding mounting holes 24d so as to secure the pad 22 to the energy absorbing body 7. A through hole 24e is also formed in substantially the center of the top wall 24 to allow for the passing of the tongue 14b of the contact plate 14 and the lead 16 therethrough. A plurality of slits 24f are formed in substantially the center of the top wall 24 to decrease the strength of the pad.

The sleeves 27, 28 surround the cores 3, 3 of the rear spoke sections S and include bores or recesses 27a, 28a.

The bores 27a and 28a extend along the circumference of the cores 3, 3 and have a width of from 5.0 to 15.0 mm. If this dbf width is less than 5.0 mm, it is difficult to prevent an increase in the amount of a shock load to be applied to the pad. If the width is more than 15.0 mm, driver's fingers may S• C

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accidentally be inserted into the bores, or the driver may feel uncomfortable.

.o C An additional bore 33 is formed between the rear eeeeC.

S side wall 31 and the top wall 24 of the insert and has a oeeo•: width of approximately 2.0 mm. The width of the bore 33 is preferably in the range between 2.0 and 15.0 mm. If this width is less than 2.0 mm, it is difficult to maintain the strength of a projection which is included in a mold to form the bore 33 in the insert 23. If the width is more than 15.0 mm, the driver may feel uncomfortable.

In the illustrated embodiment, a continuous slit 34 extends along the boundary between the top wall 24 and the side walls 29, 30 and 32. The slit 34 has three extensions 34a, 34b and 34c. The extension 34a extends forwardly from the center of the front side wall 29. The extensions 34b and 34c extend outwardly from the lateral side walls 30 and 32, respectively.

A pair of right and left nuts 29a are embedded in the lower end of the front side wall 29 adjacent to the front bent legs 9, 9 and threadedly engaged with the bolts 19 so as to secure the pad 22 to the energy absorbing body 7. An aperture 29b is formed in a portion of the front side we 9 above the nuts 29a so as to decrease the strength of the pad 22.

eeooo The cover 36 is attached to the insert 23. To this end, the cover 36 includes a retainer wall 36a to receive the.

entire peripheral edge of the insert 23. The cover 36 also includes a plurality of ribs 36b adapted to urge the contact plate 14 of the horn switch mechanism 13 toward the upper plate. The ribs 36b are located at the center of the cover •so.ei 36 and in the form of a lattice.

The steering wheel W of this embodiment will be assembled as follows.

First, the mounting hole 8b of the upper plate 8 is brought into alignment with the mounting hole 24d of the pad insert 23. Also, the mounting holes 9b of the front bent legs 9, 9 are aligned with the nuts 29a of the pad insert 23.

The bolts 19, 20 are inserted into the corresponding mounting holes to secure the pad insert 23 to the energy absorbing body 7.

The coil springs 15 are then disposed in the corresponding recesses 24a of the pad insert 23 to engage the outer peripheral edge of the contact plate 14 with the locking legs 24c of the pad insert 23. At this time, the lead 16 is inserted through the through hole 24e of the insert 23.

The lower edge of the insert 23 is received within the retainer wall 36a of the cover 36.

Thereafter, the clips 9c, 9c of the front bent legs 9, 9 are fit over the tongues 2c, 2c of the boss core 2. The ooeoo bracket Ila of the base plate 11 is secured to the bracket 2d of the boss core 2 by the bolt 18 to mount the energy S absorbing body 7 with the pad 22 to the steering wheel body M.

This completes assembly of the steering wheel W.

To practically mount the steering wheel W to an **44*4 S automotive steering shaft, the steering wheel body M is first mounted to the steering shaft. Then, the energy absorbing body 7 with the pad 22 is attached to the steering wheel body M.

With the steering wheel W thus mounted to the automotive steering shaft, the central part of the pad cover 36 is depressed to lower the contact plate 14 against the 12 biasing force of the coil springs 15. The contact 14a is then brought into contact with the contact 8a of the upper plate 8. This contact actuates the horn.

If the other part of the pad cover 36 is depressed, the pad 22 does not suffer from undesirable deformation.

This is because the major part of the pad cover 36 is supported by the pad insert 23 made of rigid synthetic resin, although the insert 23 is provided with the bores 27a, 28a, 33 and 29b and the slits 34, 24f. This rigid insert maintains the shape of the pad 22.

If a shock load F is applied to the front part of the pad 22 from forwardly and upwardly from the pad (in the direction of the arrow in Fig. then the pad 22 is moved downwardly and rearwardly from its initiril position shown in oe* Figs. 1 and 8. As a result, the sleeves 27, 28 are brought e..

into contact with the end surface of the cover 4 that oe..

surrounds the rear spoke sections 3.

As explained earlier, the bores 27a, 28a are formed in the inverted U-shaped sleeves 27, 28 and extend along the S circumference of each spoke core 3. As shown in Fig. 9, when the pad 22 is deformed, these bores 27a, 28a are narrowed to prevent an increase in the amount of the shock load F applied to the pad 22.

After the first bores 27a, 28a are narrowed, the second bore 33 which is formed between the top wall 24 and the rear side wall 31 of the insert 23 is then narrowed, as 13 shown in Fig. 10, to decrease the amount of the shock load F applied to the pad 22 when the pad 22 is further deformed.

If the shock load F continued to be applied to the pad 22, the extension 34a of the slit 34 is forwardly extended to thereby cause separation of the right and left parts of the side wall 29 (as shown by the broken arrows in Fig. Then, the bent legs 9, 9, 10, 10 of the energy absorbing body 7 is plastically deformed so as to effectively absorb the energy of the shock load F.

As shown in Fig. 11, a predetermined number of projections 27b, 28b may preferably extend within the bores 27a, 28a of the sleeves 27, 28 and contact the wall of the bores 27a, 28a when the pad 22 is deformed. Advantageously, Sa shock load to be applied to the pad 22 may be adjusted by changing the length and size of the projections 27b, 28b.

o In the illustrated embodiment, the energy absorbing 0gO** body 7 is made from a metal sheet. Alternatively, the energy absorbing body 7 may be made of urethane foam.

In the illustrated embodiment, the steering wheel W S includes four spokes. Alternatively, the steering wheel W may include three spokes. In such a case, the insert of the formed in one of the three sleeves which surrounds a reaL spoke core. Still alternatively, the steering wheel W may have two spokes. In such a case, bores may be formed in a pair of right and left sleeves of the pad insert.

In the illustrated embodiment, the bore 33 is 14 formed between the top wall 24 and the rear side wall 31 of the pad insert 23. When the steering wheel includes two spokes, the bore 33 may be formed in the same manner as when the steering wheel include four spokes. When the steering wheel includes three spokes, then a pair of bores may be formed between the top wall and the rear side wall of the pad insert at either side of the rear spoke.

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Claims (4)

1. A pad for a steering wheel, comprising an insert adapted to maintain the shape of the pad, and a pad cover adapted to cover said insert and made of a flexible material, said pad being mounted centrally on said steering wheel and adapted to abut an end surface of a steering wheel cover, said steering wheel cover extending around a spoke core of the steering wheel, wherein said insert includes a substantially inverted U-shaped section adapted to cover part of said spoke core of said steering wheel, and said section includes a recess extending along the circumference of said spoke core.

2. A pad for a steering wheel as defined in claim 1, wherein said insert includes a top wall, covering the center of said steering wheel, and a side wall extending laterally 15 and downwardly from said top wall, and a second recess is formed between said top wall and said side wall and extends laterally of said insert. o

3. A pad for a steering wheel as defied in claims 1 or 2, further comprising an 20 energy absorbing body located below said pad. 0

4. A p? for a steering wheel substantially as hereinbefore described with reference Sto the drawings. 0 DATED this 13th day of June 1996 TOYODA GOSEI CO., LTD By Its Patent Attorneys Davies Collison Cave <p:\wpdocs\Nnap\spcci\

782800.i6a ABSTRACT OF THE DISCLOSURE A pad 22 is mounted on the center of a steering wheel W and covers the end surface of a cover 4 which in turn, extends around rear spoke cores 3, 3. The pad 22 comprises an insert 23 adapted to maintain the shape of the pad 22, and a cover 36 adapted to cover the insert 23 and made of a flexible material. The insert 23 includes sleeves 27, 28. The sleeves 27, 28 have a substantially inverted U- shaped section and cover the spoke cores 3, 3. Bores or recesses 27a, 28a are formed in the sleeves 27, 28 and extend along the circumference of the spoke cores 3, 3. When a shock load is applied to the front part of the pad from forwardly and upwardly of the pad, the pad 22 is so deformed as to decrease the amount of the shock load while maintaining S the original shape of the pad. V °e o