GB2290337A

GB2290337A - Preventing vibration in seat catch operating mechanism

Info

Publication number: GB2290337A
Application number: GB9411433A
Authority: GB
Inventors: Stanislaw Wieclawski
Original assignee: ACG Deutschland GmbH
Current assignee: ACG Deutschland GmbH
Priority date: 1994-06-08
Filing date: 1994-06-08
Publication date: 1995-12-20
Anticipated expiration: 2014-06-08
Also published as: ES2124133A1; DE19520738A1; GB9411433D0; ES2124133B1; GB2290337B; DE19520738C2

Description

1 EEAT BACKREST CATCH MECHANISM 2290337 The present invention relates to a

catch mechanism of a seat backrest of, for example, a vehicle seat.

In many modern vehicles, it is common to allow the rear seat backrests to pivot forwardly so as to increase the size of the luggage compartment. A known arrangement for securing the seat backrest in the upright position is to have a hook secured to the vehicle body and a catch mechanism on the backrest.

The hook may take the form of a C-shaped metal rod having its two free ends welded or otherwise secured to the vehicle body.

The catch mechanism is generally embedded in the seat backrest and includes a recess in the backrest for receiving the hook, a catch being located in the recess for engagement with the hook. The release mechanism typically includes a button at the top of the seat backrest coupled to a link rod which co- operates with the catch to release the catch from the hook when the button is depressed. The release button is located within a housing secured to the vehicle seat backrest, the housing being provided to guide the movement of the button.

A problem with the above type of backrest catch mechanism is that the button tends to rattle in the housing, causing annoyance to the driver and passengers. The present invention seeks to provide an improved catch mechanism of a seat backrest.

According to an aspect of the present invention, there is provided a catch mechanism of a seat backrest including a catch capable of engagement with a hook, a release button actuable to move the catch to a disengaging position and a housing within which the release button is reciprocably movable 2 between a rest position and a catch disengaging position; the button including a body portion generally spaced from the housing and at least one protrusion extending from the body portion by an extent which causes the button to be a tight fit in the housing when the button is in the rest position.

The provision of one or more protrusions can prevent rattle of the button within the housing without significantly increasing resistance of movement of the button.

Preferably, two protrusions are provided on opposing sides of the body portion of the release button.

In the preferred embodiment, the spacing between internal surfaces of the housing is relatively greater in the region of the protrusion or protrusions from a position intermediate the rest position and the catch disengaging position of the button. In this manner, after the button has been depressed by a predetermined amount, the protrusion or protrusions have no effect, thereby facilitating movement of the button into the housing.

Preferably, the housing includes one or more elongate recesses aligned with the or each protrusion and extending in the direction of movement of the button, the or each recess extending from a position intermediate the rest and catch disengaging positions of the button to the catch disengaging position. Elongate recesses can provide the desired space between the protrusion(s) and the housing and can also guide the movement of the button in the housing.

Alternatively, the housing may include one or more slots aligned with the or each protrusion and extending in the direction of movement of the button, the or each slot extending from a position 3 intermediate the rest and catch disengaging positions of the button to the catch disengaging position. This latter arrangement is preferred since it can provide the same benefits of elongate recesses while being more readily manufactured.

The present invention is also directed to a vehicle seat including a pivotable backrest and a catch mechanism as specified above.

An embodiment of the present invention is described below, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 is a perspective view of an embodiment of catch mechanism fitted to a vehicle seat backrest; Figure 2 is a cross-sectional view of a release button and housing of the catch mechanism of Figure 1, taken along line 2-2 of Figure 1; Figure 3 is a cross-sectional view of the release button and housing of Figure 2, taken along line 3-3 of Figure 2; and Figure 4 is a cross-sectional view of the button and housing of Figure 2, taken along line 4-4 of Figure 2.

Referring to Figure 1, the embodiment of backrest catch mechanism 10 shown is fitted to the rigid structure 12 of a backrest of a rear seat of a passenger compartment of a vehicle. Figure 1 is a perspective view from the front of the back rest, in other words showing the part of the backrest which faces the interior of the passenger compartment. The cushioning for the backrest envelops the catch mechanism 10, while the rear of the rigid structure 12 is normally covered in carpeting similar to that used to line the floor of the boot.

4 The rigid structure 12 includes a box 16 forming a recess when viewed from the rear of the backrest. The box 16 in use receives a hook (not shown) located in the boot of the vehicle. Located over the box 16 is a backrest catch unit 14 which includes a catch (not visible) of conventional form extending into the box 16. The catch is integral with a rotatable shaft 18 so as in use to be rotated between a locked position in which it engages the hook to lock the backrest in the upright position (as shown) and an unlocked position in which it is disengaged from the hook so as to allow the backrest to be pivoted forwardly into a lying position.

The shaft 18 is supported rotatably between two supports 20 fixed to the box 16. A first link 22 is integral with the shaft 18 and has a bore 24 which receives a first end of a link rod 26.

Link rod 26 links the catch unit 14 to a release button unit 30, formed of a support frame 32, a button housing 34 and a release button 36. The support frame 32 is basically a sheet of metal folded to have two opposing walls, the lower wall facing the catch unit 14, the upper wall facing the top of the backrest. The lower wall includes an aperture for receiving the link rod 26, while the upper wall includes an aperture which receives the housing 34. The release button 36 and the housing 34 are preferably made from a plastics material.

The button 36 includes a bore 45 (Figure 2) for receiving the second end of the link rod 26.

Referring to Figures 2 to 4, the button housing 34 is of rectangular shape when viewed in plan and includes upper and lower housing portions 40,42. The upper housing portion 40 houses and guides the movement of the button 36, while the lower housing T portion 42 guides the movement of a coupling shaft 44 extending from the button 36. The upper housing portion 40 also includes opposing slots 46, 48 extending in the direction of movement of the button 36 and in this embodiment along the longitudinal axis of the housing 34. The slots 46,48 extend to a position just short of the button 36 when the button 36 is in the upper, rest position shown in Figure 1.

At the top of the housing 34, there is provided a curved peripheral flange 38 which in use extends above the cushioning and cover of the backrest. A plurality of resilient bosses 50 and associated shoulders 52 extend from the outer surfaces of the housing and are used in securing the housing in the aperture of the upper wall of the support frame 32 and other supports provided (not shown).

The release button 36 is also of rectangular shape when viewed in plan and is hollow to reduce its weight. The upper surface 54 of the button 36 is convex for the sake of appearance. As can be seen better in Figures 3 and 4, the body portion of the button 36 is smaller than the inner dimensions of the housing 34 so as to be spaced from the housing 34. This ensures that the housing 34 provides no resistance to the movement of the button 36 and allows relatively wide manufacturing tolerances.

Secured to the interior surface 56 of the button 36 is the coupling shaft 44 which is of generally rectangular form in longitudinal cross-section. A plurality of reinforcing ribs (not shown) may be provided at the junction between the button 36 and the coupling shaft 44. The free end 58 of the coupling shaft 44 includes a bore 45 which in use receives the upper end of the link rod 26 and a pair of stops 62 which in use abut shoulders 62 6 extending within the lower housing portion 42. The stops 60 and shoulders 62 limit the movement of the button 36 out of the housing 34, keeping it in the rest position. The shoulders 62 are resiliently coupled to the lower housing portion 42 so as to enable the free end 58 of the coupling shaft 44 to pass the shoulders 60 when the button 36 is fitted into the housing 34 during assembly.

Extending from opposing sides of the button 36 are two studs 64. The studs 64 of a size so as cause the button 36 to be a tight fit in the housing 34 when in the housing. In the preferred embodiment, the distance between the outer ends of the studs 64 is slightly greater than the space between the opposing inner surfaces of the associated walls of the housing 64, such that the button 36 reaches the rest position shown in Figures 2 and 3 by resilient deformation of the button 36 and/or housing 34. In this manner, the button 36 is held tightly in the housing 34 when in the rest position.

In some embodiments, the housing 34 may have shallow recesses in the area of the studs 64, as seen in Figures 2 and 3, for preventing movement of the button 36 in a direction orthogonal to the line between the studs 64.

Each stud 64 is aligned with a respective one of the two slots 46,48 such that on depression of the button 36 into the housing 34, the studs 64 register with the slots 46,48 and provide no further resistance to the movement of the button 36. The distance the button 36 has to move before the studs 64 reach the slots 46,48 is chosen to be as little as possible so as to ensure that the studs 64 offer little or substantially no resistance to the movement of the button 36 at the beginning of its travel into v 7 the housing 34. It is possible with a suitable design for the studs 64 just to rest at the end of the slots 46,48.

Depression of the button 36 into the housing causes the link rod 26 to pivot the shaft 18 and thereby to rotate the catch out of engagement with the hook. The backrest can then be pivoted to its lying position. on release of pressure on the button 36, a spring (not shown) coupled to the catch unit 14 pivots the shaft 18 into the catch engaging position and thereby the link rod 26 upwardly as viewed in Figure 1. This upward movement of the link rod 26 pushes the button 36 towards its rest position, causing the studs 64 to re-engage the internal sides of the housing 34, as shown in Figures 2 and 3. Thus, the button 36 can be prevented from rattling in the housing 34 in a manner which does not noticeably increase resistance of movement of the button 36 in the housing 34. 20 Slots 46,48 have been chosen for ease of manufacture. It could equally be possible to provide grooves in place of the slots 46,48. Alternatively, it would be possible to design the housing 34 in such a manner that its interior, at least in the region of the studs 64, has a larger dimension than at the top of the housing, such that on depression of the button 36, the studs 64 reach the larger dimension portion and provide no further resistance to the movement of the button 36.

8

Claims

Claims:

1. A catch mechanism of a seat backrest including a catch capable of engagement with a hook, a release button actuable to move the catch to a disengaging position and a housing within which the release button is reciprocably movable between a rest position and a catch disengaging position; the button including a body portion generally spaced from the housing and at least one protrusion extending from the body portion by an extent which causes the button to be a tight fit in the housing when the button is in the rest position.

2. A catch mechanism according to claim 1, wherein two protrusions are provided on opposing sides of the body portion of the release button.

3. A catch mechanism according to claim 1 or 2, wherein the spacing between internal surfaces of the housing is relatively greater in the region of the protrusion or protrusions from a position intermediate the rest position and the catch disengaging position of the button.

4. A catch mechanism according to claim 3, wherein the housing includes one or more elongate recesses aligned with the or each protrusion and extending in the direction of movement of the button, the or each recess extending from a position intermediate the rest and catch disengaging positions of the button to the catch disengaging position.

5. A catch mechanism of a seat backrest substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

5. A catch mechanism according to claim 3, wherein the housing includes one or more slots aligned with the or each protrusion and extending in the direction of movement of the button, the or each slot extending from a position intermediate the rest and catch disengaging positions of the button to the catch disengaging position.

9 f

6. A vehicle seat including a pivotable backrest and a catch mechanism according to any preceding claim.