GB2162890A

GB2162890A - Seat reclining angle adjustment device

Info

Publication number: GB2162890A
Application number: GB08518193A
Authority: GB
Inventors: Takeshi Tezuka; Akira Owada
Original assignee: Shiroki Corp; Shiroki Kinzoku Kogyo KK
Current assignee: Shiroki Corp
Priority date: 1984-08-09
Filing date: 1985-07-18
Publication date: 1986-02-12
Also published as: AU4178585A; AU572989B2; JPH0336283Y2; DE3524814A1; GB2162890B; GB8518193D0; JPS6137850U

Abstract

A reclining angle adjustment device for use with a reclining seat of a motor vehicle includes a first arm (1), a handle shaft rotatably mounted on the first arm and rotatable by a manually actuatable handle (24), a second arm (2) pivotally mounted on the first arm, a transmission device (26) mounted on the first arm and operatively coupled to the handle shaft, a planetary gear mechanism disposed between the first and second arm and operated by the transmission device (26) for tilting the second arms with respect to the first arm in response to angular movement of the handle and a device for holding the handle shaft immobile comprising a case on the first arm (1) which receives in normally gripping engagement a coil spring which in turn receives a core mounted on the shaft, the core releasing the gripping action of the spring when the handle is turned. A driver member is entrained by the rotating spring to operate the transmission. <IMAGE>

Description

SPECIFICATION Reclining angle adjustment device The present invention relates to a reclining angle adjustment device for adjusting the angle of inclination of the seat back of a reclining seat in a motor vehicle, i.e., the reclining angle of the reclining seat.

There are known reclining angle adjustment devices in which the reclining angle is adjusted by means of a planetary gear mechanism. Other known reclining angle adjustment devices have a control handle positioned remotely from the center of tilting movement of the seat back of the reclining seat, or an upper arm of the device, for easy adjustment of the reclining angle, as disclosed in Japanese Laid-Open Utility Model Publication No.

56-158953, for example.

The planetary gear mechanism employed in the reclining angle adjustment device is composed of an inner gear, an outer gear, and an angularly movable shaft by which the inner and outer gear are held in mesh with each other. More specifically, the angularly movable shaft has an eccentric portion on which the outer gear is mounted, and a concentric portion on which the inner gear is mounted, thus keeping the inner and outer gears in mesh with each other. The inner gear is coupled- to the seat back, while the outer gear is coupled to the seat cushion of the reclining seat. The reclining angle can be adjusted by turning the angularly movable shaft with the control handle.

While the motor vehicle in which the reclining angle adjustment device is incorporated is running, the inner gear vibrates with respect to the outer gear due to vibrations of the motor vehicle, with the result that the angularly movable shaft is temporarily freed for rotation with the control handle. When this happens, the seat back is tilted so that the reclining angle varies with time.

It is an object of the present invention to provide a reclining angle adjustment device which will prevent the reclining angle from varying with time.

Another object of the present invention is to provide a reclining angle adjustment device having a relatively simple structure to prevent an angularly movable shaft from being freely rotated about its own axis.

According to the present invention, there is provided a reclining angle adjustment device comprising a first arm, a handle shaft rotatably mounted on the first arm and rotatable by a manually actuatable handle, a second arm pivotally mounted on the first arm, a transmission device mounted on the first arm and operatively coupled to the handle shaft, a planetary gear mechanism disposed between the first and second arm for tilting the second arm with respect to the first arm in response to angular movement of the handle, transmitted through the handle shaft and the transmission device, a stopper case mounted on the lower arm adjacent to the handle shaft, a coil stopper spring disposed in the stopper case and resiliently pressed against the inner wall surface of the stopper case, the coil stopper spring having two hooks, a core positioned in the stopper spring and having a recess with the two hooks disposed therein, the core being angularly movable with the handle shaft, and a tongue disposed between the hooks of the coil stopper spring, the transmission device including a driver rotatable with the tongue.

The above and other objects, features and advantages of the present invention will become more apparent from the following description when taken in conjunction with the accompanying drawings in which a-preferred embodiment of the present invention is shown by way of illustrative example. In the drawings: FIG. 1 is a side elevational view of a reclining angle adjustment device according to the present invention; FIG. 2 is a cross-sectional view taken along line Il-Il of FIG. 1; FIG. 3 is a cross-sectional view taken along line Ill-Ill of FIG. 1; FIG. 4 is a cross-sectional view taken along line IV--IV of FIG. 1; and FIG. 5 is an exploded perspective view of a brake mechanism.

FIGS 1 to 5 show a reclining angle adjustment device having lock mechanisms disposed respectively on the outer and inner sides of a reclining seat. Only the lock mechanism on the outer side is shown as the lock mechanism in the inner side is of the same construction.

The reclining angle adjustment device includes a lower arm 1 fixed as by screws to the seat cushion frame (not shown) of a reclining seat, and an upper arm 2 fixed as by screws to the seat back frame (not shown) of the reclining seat. The upper arm 2 has an inner gear 2a embossed on a side thereof as by precision pressing. The upper arm 2 has a circular hole 2e defined in an upper portion thereof as an attachment hole for passage therethrough of the fastener toward the seat back frame. An intermediate gear plate 3 is disposed adjacent to the upper arm 2 and has an outer gear 3a embossed as by precision pressing on a side thereof facing the inner gear 2a of the upper arm 2. The intermediate gear plate 3 also has a rack 3b on an outer edge thereof.In the illustrated embodiment, the rack 3b is composed of a first tooth for holding the seat back in an intermediate position and a second tooth for holding the seat back in a rearwardly tilted position. However, the rack 3b may be composed of three or more teeth. The number of teeth of the inner gear 2a is selected to be at least one larger than the number of teeth of the outer gear 3a.

A pawl 4 is pivotally mounted on the lower arm 1 by a stepped pin 5 and has locking teeth 4a for engaging the rack 3b of the intermediate gear plate 3. A pin 7 is mounted on the pawl 4 near the locking teeth 4a and projects in a direction opposite to the lower arm 1, the pin 7 being inserted in a cam slot 8c defined in an intermediate portion 8a of a release lever 8. A subplate 9 is positioned more closely than the release lever 8 to the lower amr 1. The subplate 9 has attachment holes corresponding in position to the stepped pin 5 and stepped pins 10, 11, and is secured through the attachment holes to the lower arm 1 to prevent the upper arm 2, the intermediate gear plate 3, and the pawl 4 from being disassembled. An angularly movable shaft 1 2 includes an eccentric portion 1 2a disposed partially on a concentric portion thereof.

For assembly, the concentric portion of the through a bushing 14 of the lower arm 1, a central hole defined in the intermediate gear plate 3 in concentric relation to the outer gear 3a, the subplate 9 on which the release lever 8 is angularly movably mounted, and a spacer 16 fixed to the subplate 9. The eccentric portion 1 2a of the angularly movable shaft 1 2 is angularly movably inserted through a hole defined in the upper arm 2 in concentric relation to the inner gear 2a. A sprocket 1 3 is mounted on one end of the concentric portion of the angularly movable shaft 1 2 for angular movement therewith.Thus, the upper arm 2 and the intermediate gear plate 3 are angularly movably mounted respectively on the eccentric portion 1 2a and the concentric portion of the angularly movable shaft 12, and the inner gear 2a and the outer gear 3a are held in mesh with each other, thereby providing a planetary gear mechanism.

A release arm plate 1 7 is angularly movably mounted on the concentric portion of the angularly movable shaft 1 2 and has an extension 1 7b extending downwardly to the right in FIG. 4 to serve as a walk-in pedal. The release arm plate 1 7 also has in its intermediate portion a hole 1 7a in which there is fitted a hook 19a of a hook plate 19 fixed to a connecting pipe 1 8 for rough adjustment of the reclining angle of the reclining seat. The connecting pipe 1 8 serves to transmit the motion of the release lever 8 to the release lever of the identical lock mechanism disposed on the inner side of the reclining seat.The hook 1 9a has a width selected to be smaller than the width of the hole 1 7a in the release arm plate 1 7 in order to take up the difference between locking positions of the lock mechanisms on the outer and inner sides, thus preventing the reclining seat back from being partly locked. A connecting bar 20 for fine adjustment of the reclining angle is connected to the angularly movable shaft 1 2 for transmitting the motion of the angularly movable shaft 1 2 to the angularly movable shaft of the inner lock mechanism. The release arm plate 1 7 has its distal end secured by a stepped pin 21 to the intermediate portion 8a of the release lever 8.A roller 22 is fitted over the stepped pin 21 and held against the back of the pawl 4 to maintain the locking teeth 4a of the pawl 4 and the rack 3b of the intermediate gear plate 3 in reliable mesh with each other.

As better shown in FIGS. 4 and 5, a brake mechanism 23 is mounted on the lower arm 1. The brake mechanism 23 includes a handle shaft 43 with a control handle 24 mounted on one end thereof.

The brake mechanism 23 has a stopper case 41 fitted in a hole la in the lower arm 1 and riveted to the lower arm 1, and a cover bracket 42 riveted to the lower arm 1 in confronting relation to the cylindrical recess in the stopper case 41. The stopper case 41 and the cover bracket 42 have central holes in which the handle shaft 43 are inserted and angularly movably supported. The handle shaft 43 includes a core 43a with a recess, near the end of the handle shaft 43 close to the stopper case 41. The handle shaft 43 also has a serrated portion 43b near the end thereof close to the cover bracket 42 for supporting the control handle 24 thereon. A substantially cylindrical sprocket shaft 44 is fitted angularly movably over the handle shaft 43, and has on one end thereof a tongue 44a disposed in the recess of the core 43a.The sprocket shaft 44 has a sprocket 44b on an outer peripheral surface thereof. A coil stopper spring 45 is disposed in the stopper case 41 and pressed against the inner wall surface of the stopper case 41. In its free state, the coil stopper spring 45 has an outside diameter slightly larger than the inside diameter of the stopper case 41. The stopper spring 45 has opposite ends bend radially inwardly into hooks 45a. The core 43a is disposed in the stopper spring 45 with the hooks 45a positioned in the recess of the core 43a, the tongue 44a being located between the hooks 45a.

A chain 26 is trained around the sprockets 44b, 1 3 and has intermediate portions guided by chain guides 27 mounted on the lower arm 1. A spring 28 acts between the release lever 8 and the lower arm 1 for normally urging the pawl 4 to turn in a direction to mesh with the intermediate plate 3. A pin bracket 29 is secured by the- stepped pins 10, 11 to the lower arm 1, with a grooved pin 30 is fixed to the pin bracket 29. A balancing spiral spring 31 has an inner end disposed in the longitudinal groove of the pin 30. A hook plate 32 is angularly movably mounted on the pin 30. The spiral spring 31 has an outer end held in engagement with a hook 32a of the hook plate 32. The hook plate 32 also has a bent portion 32b with its side held against a hook 3e of the intermediate gear plate 3.

A cable attachment bracket 33 is fixed to the upper arm 2 by a pin 34. When the upper arm 2 is tilted in a forward direction, the bracket 33 pulls the cable end 35b of an inner cable member 35a of a walk-in control cable 35 out of an outer cable sheath 35c.

The pin 34 also serves as a stopper pin for limiting the range of angles for fine adjustment of the reclining angle. The pin 34 is positioned in a recess 3e of the intermediate gear plate 3 for allowing the upper arm 2 to be tilted in the angular range defined between front and rear ends 3f, 39 of the recess 3e with which the proximal end of the pin 34 is engageable.

The lock mechanism on the inner side of the reclining seat is substantially the same as that described above. However, since the release lever is operated only on the outer side of the reclining seat, the inner lock mechanism does not have the control portion 8b of the release lever 8, the extension 1 7b of the release arm plate 1, and the control handle 24.

Operation of the reclining angle adjustment device of the foregoing construction is as follows: In the position shown in FIG. 1, the locking teeth 4a of the pawl 4 mesh with the rack 3b of the intermediate gear plate 3 to lock the gear plate 3. Therefore, the outer gear 3a is fixed with respect to the lower arm 1. By turning the control handle 24, the handle shaft 43 and the core 43a integral therewith are turned. Right after they have turned, the hooks 45a of the stopper spring 45 abut against the ends of the recess of the core 43. Since the force applied from the handle shaft 43 tends to compress the stopper spring 45 to reduce its diameter, the frictional resistance between the stopper spring 45 and the stopper case 41 is reduced.

The handle shaft 43 can smoothly be turned unobstructedly, and the sprocket shaft 44 is turned by the tongue 44a with the handle shaft 43. Therefore, the angularly movable shaft 1 2 is turned by the chain 26 to cause the upper arm 2 to turn at a prescribed speedreduction ratio through the planetary gear mechanism. Accordingly, the reclining angle can be adjusted finely in the angular range between the front and rear ends 3f, 3g of the recess 3e of the intermediate gear plate 3.

For rough adjustment of the reclining angle, the control portion 8b of the release lever 8 is turned clockwise in FIG. 1 by the passenger on the reclining seat. The roller 22 is also turned clockwise in a direction to disengage from the pawl 4. (The lower arm 1 has arcuate holes defined therein to allow the pins 7, 21 to move therein for permitting the roller 22 to turn as described above.) The pin 7 in the cam slot 8c now moves toward the control handle 24. The locking teeth 4a are then brought out of mesh with the rack 3b of the intermediate gear plate 3, which is now unlocked. Thus, the reclining angle can now be roughly adjusted, or the seat back can be quickly tilted as desired. The lock mechanism on the inner side of the reclining seat operates in the same manner.

When the reclining angle adjustment device of the invention is subjected to forces tending to turn the shaft 1 2 about its own axis due to vibrations, such forces act through the tongue 44a of the sprocket shaft 44 to expand the stoper spring 45 to increase its diameter, i.e., to increase the force with which the stopper spring 45 is pressed against the pinion case 41. As a consequence, the frictional force between the stopper spring 45 and the pinion case 41 is increased to prevent the angularly movable shaft 1 2 from being turned of its own accord.

With the present invention, therefore, the simple brake mechanism is disposed in the control handle assembly for preventing the control handle from being turned of its own accord. Therefore, the reclining angle is also prevented from varying with time.

Although a certain preferred embodiment has been shown and described, it should be understood that many changes and modifications may be made therein without departing from the scope of the appended claims. For example, the lock mechanisms have been described as being provided on the outer and inner sides of the reclining seat, only the outer lock mechanism may be provided and the reclining seat may only be hinged on the inner side thereof. The rough adjustment means as described above may be dispensed with. The upper arm is remotely controlled by the chain transmission mechanism, the upper arm can be remotely controlled by a belt transmission device composed of a belt and pulleys or a grooved belt and grooved pulleys, or other transmission devices.

Claims

1. A reclining angle adjustment device comprising: (a) a first arm; (b) a handle shaft rotatably mounted on said first arm and rotatable by a manually actuatable handle; (c) a second arm pivotally mounted on said first arm; (d) a transmission device mounted on said first arm and operatively coupled to said handle shaft; (e) a planetary gear mechanism disposed between said first and second arm for tilting said second arm with respect to said first arm in response to angular movement of said handle, transmitted through said handle shaft and said transmission device; (e) a stopper case mounted on said lower arm adjacent to said handle shaft; (f) a coil stopper spring disposed in said stopper case and resiliently pressed against the inner wall surface of said stopper case, said coil stopper spring having two hooks;; (g) a core positioned in said stopper spring and having a recess with said two hooks disposed therein, said core being angularly movable with said handle shaft; and (h) a tongue disposed between said hooks of the coil stopper spring, said transmission device including driver means rotatable with said tongue.

2. A reclining angle adjustment device according to claim 1, wherein said transmission device comprises a chain, said driver means comprising a sprocket around which said chain is trained.

3. A reclining angle adjustment device according to claim 2, wherein said core is integral with said handle shaft, including a sprocket shaft with said sprocket disposed thereon, said sprocket shaft being angularly movably fitted over said handle shaft, said tongue being mounted on said sprocket shaft.

4. A reclining angle adjustment device substantially as hereinbefore described, and as shown in, the accompanying drawings.