GB1566288A

GB1566288A - Reclining mechanism for a seat

Info

Publication number: GB1566288A
Application number: GB4959376A
Authority: GB
Original assignee: TURNER Ltd H
Current assignee: TURNER Ltd H
Priority date: 1977-04-29
Filing date: 1977-11-23
Publication date: 1980-04-30

Description

(54) RECLINING MECHANISM FOR A SEAT (71) We, H.R. TURNER (WIL LENHALL) LIMITED, of Holly Lane, Great Wyrley, Walsall WS6 6AJ, a British Company, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement : This invention relates to a hinge fitting for hingedly connecting together the seat base and backrest of a seat, e.g. a vehicle seat, the fitting being provided with a reclining facility.

Such hinge fittings are commonly used in vehicle seats in order that the backrest can be adjusted in inclination and have to cope with both small angle adjustments from the normal seating position, e.g. over a range of say 10 , and large angle adJustments in circumstances where the backrest is to be fully reclined. Many hinge fittings of this kind employ a pinion and rack type mechanism and are subject to the drawback that, while relatively small teeth are required to obtain relatively fine adjustments of the backrest, when the backrest is to be displaced through a large angle, the pinion has to be rotated a large number of revolutions.

The object of the present invention is to overcome this drawback.

According to the present invention we provide a hinge fitting comprising first and second parts hingedly connected together and means actuable by a rotary member for effecting relative angular movement between said parts, said means coupling together said parts in such a way that turning movement of said rotary member is nonlinearly related to the relative angular movement between said parts, Preferably said means comprises a toothed rack mounted on one of said parts, a rotary gear member in mesh with said rack whereby rotation of the gear member displaces the rack relative to said one part, and a connecting link pivotally connecting said rack and the other part, the arrangement being such that the pivotal connection between the link and said other part is spaced from the hinge axis of the two parts, and the pivotal connection between the link and the rack moves in a trajectory which is non-concentric with respect to the hinge axis, as the rack is displaced by said gear member.

The gear member may be in the form of a conventional pinion gear but, in that event, provision must be made of means, e.g. a ratchet or clutch device, for preventing rotation of the pinion induced by forces acting on said parts. Alternatively, the gear member may be a worm-type gear in which case a ratchet device may not be necessary. Preferably however, the gear member comprises at least two, preferably three, elements equiangularly spaced from one another about the rotational axis of said rotary member and arranged to engage with the rack, the rotary member being mounted for displacement relative to the rack so that the elements may roll over the rack teeth as they are rotated, spring means being provided to bias the rotary member into a position in which two of said elements are fully engaged with intertooth spaces of the rack. The advantage of this particular arrangement is that the rotary member is self-locking with respect to forces acting between said parts and tending to induce rotation of the gear member.

Conveniently the rack is of arcuate configuration and is angularly displaceable relative to said one part, the pivotal connection between said link and the rack being spaced from the axis about which the rack is angularly movable. The rack may for example be of part-circular configuration and be pivoted to said one part at its centre of curvature.

Where the rack is arcuate as aforesaid, the arrangement may be such that when the gear engages one end of the rack, the pivotal connections between the link and the rack and between the link and said other hinge part are substantially aligned with the pivotal connection between the rack and said one hinge part, the latter pivotal connection being located between the other two pivotal connections.

In practice the hinge fitting will be duplicated at each side of the seat and the rotary members thereof will be coupled together across the width of the seat so that they can be operated together by a single handle or knob.

The invention will now be described by way of example only with reference to the accompanying drawings, in which Figure 1 is a side view of a vehicle seat hinge fitting; Figure 2 is an enlarged fragmentary view showing the gear member in greater detail; Figure 3 is a side view of a second embodiment; Figure 4 is an end view taken in the direction 4 in Figure 3, and Figure 5 is a section in the direction 5 -- 5 in Figure 3.

Referring now to Figure 1, the hinge fitting comprises a first plate 10 and a second plate 12 pivoted together at 14 and an adjustment mechanism comprising an arcuate toothed rack 20 pivoted to the plate 10 at 22, a connecting link 24 coupling the rack 20 and plate 12 at points 26 and 28 and a rotary gear member or pinion device 30 engaging the rack 20. In practice, the hinge fitting is duplicated at each side of a vehicle seat with the plates 12 connected to, or forming part of the seat cushion frame and the plates 10 attached to, or forming part of the backrest frame. The pinion 30 is operable to turn the rack 20 angularly and further description of the pinion and rack arrangement will be given below.

When the pinion is at one end 20A of the rack the link 24 will be oriented so that the pivotal connections 22, 26 and 28 lie on the same line 40 and the backrest occupies a normal seating position. As the pinion is rotated, counterclockwise as seen in the drawing, the rack is displaced angularly about its pivotal connection 22. Consequently, the lower end of the link 24 is raised and angular movement of the rack is translated into tilting movement of the backrest about pivot 14. Thus, the backrest can be tilted to the desired inclination and will remain in that position until further rotation of the pinion, via the knob or handle, is effected.

It will be noted that there is a non-linear relationship between rotation of the pinion (and hence the rack) and tilting of the backrest as a result of the provision of the connecting link. Initially, pinion rotation will be translated into tilting of the backrest through relatively small angles because the connection 26 initially moves with a predominantly horizontal component but as the rack turns further the vertical component of movement of the connection progressively increases giving rise to larger angular movement of the backrest for each revolution of the pinion.

Eventually however, as the remote end of the rack approaches engagement with the pinion, the angular movement of the backrest per revolution of the pinion will begin to decrease again. In this way, it is possible to obtain fine adjustments of the backrest over a range of say 70" from the normal seating position and also larger angle adjustments towards a fully reclined position, and in the latter case the pinion does not have to be turned through a large number of revolutions as would be necessary if the relationship between pinion rotation and backrest tilting were linear.

A feature of the invention is the selflocking action of the pinion, thus obviating the need for a separate locking device for preventing unintended angular movement of the rack 20, as will now be explained.

The pinion device 30 is mounted on the plate 10 for sliding movement radially of the rack 20 in a profiled guide aperture 58, and comprises three parallel pins 50A, B and C which are equiangularly spaced with respect to the rotary axis 52 of the device. The pinion device is radially movable under the action of spring-loading which biasses the device into the illustrated stable locking position where two of its pins seat firmly within adjacent intertooth spaces of the arcuate rack 20 and resist any tendency for the latter to rotate about axis 26 due to the load exerted on the backrest attachment plate 10.

Associated with the pins 50 is a cam 54 which is rotatably fast with the pins and has three lobes 56A, B and C of part-circular contour substantially centred on the respective pins. The cam 54 rotates within the aperture 58 whose periphery is profiled to control movement of the cam as hereinafter explained. The aperture 58 includes a crest 60 whose apex lies on the line passing through axes 22 and 52 a concavity 62A, B on each side of the crest 60 and radiussed cusps 64A, B surfaces 66A, B whose curvature at least approximates to that of the tooth flanks.

To illustrate operation of the device suppose that it is desired to incline the plate 10 rearwardly from the illustrated position, then it will be necessary to rotate device 30 counterclockwise by means of a handle, knob or lever (not shown) coupled thereto. Initially, rotation of the device about its axis 52 will be translated into a radial shifting movement caused by turning of the device about the pin 50B which remains in engagement with the rack 20 whilst the pin 50C moves out of engagement. Surface 66A assists in con straining the pinion device to move in this manner. At this stage, no movement of the rack occurs. Eventually, the lobe 56A of the cam engages with and seats in concavity 62B and further rotation of the pinion is translated into a turning movement about the pin 50A with consequent displacement of the pin 50B and rotation of the rack. Such movement continues until the lobe 56C engages with, and seats in, the concavity 62A whereupon the rotation of the pinion 30 is translated into turning about the pin 50C with continued turning of the rack by pin 50B and accompanying movement of the pin 50A towards meshing engagement with the rack.

As the pin S0A passes cusp 64B, the effective turning point of the pinion becomes pin 50B and as pin 50A enters the aligned intertooth space, the pin 50C moves into registry with the crest 60. The pinion has by then assumed the stable, locking position illustrated in the drawing and for a 1200 rotation of the pinion, the rack has been displaced through one tooth pitch.

It will be noted that the curvature of the surfaces 66A, B co-operates with the cam lobes to resist unintended turning of the pinion and that the registry between the crest 60 and the adjacent cam lobe provides a failsafe feature in the event of breakage of the spring loading the pinion radially inwardly.

In this event, the cam lobe will engage the crest to overcome the tendency for the pinion to turn due to loading of the backrest plate 10.

In a modification of the illustrated embodiment, the cam 54 can be omitted and the pins 50A, B, C may co-operate directly with the profiled aperture 58 as shown in Figure 2.

In Figure 2 the path of movement of each pin is indicated by reference numeral 70. Direct engagement between the pins and the profiled aperture is not favoured however because of the increased wear to which the pins are then subject. In another modification, there may be only two pins disposed diametrally opposite each other; three pins are preferred however because the extent of the radial shift or wobble of the pinion device is reduced and the rotational movement per tooth pitch advance is 1200 instead of 1800.

It is also within the ambit of the invention to use four or more pins or other intertoothmeshing elements with appropriate modifications of the profiled guide surfaces.

As mentioned, the hinge fitting of Figure 1 may be duplicated at each side of the seat in which case the pinion devices 30 will be coupled together by a shaft or the like so that both can be operated by a single handle or lever. Alternatively the mechanism can be provided at one side only with a plain hinge fitting at the other side.

Although this type of pinion device described above is preferred because it is self-locking, other types of pinion could be used, e.g. a conventlonal pinion gear, but in that event some means, e.g. a ratchet or clutch device, is necessary for preventing unintended turning of the pinion by the forces acting on the backrest. In another modification, a worm gear may be used in place of the pinion and in this event, a ratchet or clutch device may not be necessary.

Although the rack is of semi-circular configuration in the illustrated embodiment, other configurations are possible; for example, the rack may, in some instances, be of generally linear configuration, ie. with its teeth arranged along a straight line.

Figures 3 to 5 show another modification of the invention in which like parts are designated by the same reference numerals as in Figure 1. In this embodiment, the rack 20 is circular, the link 24 is somewhat smaller in length and the pivot 14 between the plates 10 and 12 lies within the periphery of the rack 20. The pivot 14 in this case is supported by an additional plate 72 which is secured to the plate 10 so as to sandwich the rack 20 and plate 12 therebetween, and the rack 20 is formed with an arcuate slot 74 concentric with the journal 22 connecting the rack 20 to the plate 12, through which slot the pivot 14 extends. In operation, clockwise turning of the pinion 30 causes anticlockwise turning of rack 20 thus causing pivot 26 to move about journal 22 with consequent displacement of the link 24 and hinging of plate 10 relative to plate 12.

WHAT WE CLAIM IS: 1. A hinge fitting comprising first and second parts hingedly connected together and means actuable by a rotary member for effecting angular movement between said parts, said means coupling together said parts in such a way that turning movement of said rotary member is non-linearly related to the relative angular movement between said parts.

2. A hinge fitting as claimed in Claim 1 in which said means comprises a toothed rack mounted on one of said parts, a rotary gear member in mesh with said rack whereby rotation of the gear member displaces the rack relative to said one part, and a connecting link pivotally connecting said rack and the other part, the arrangement being such that the pivotal connection between the link and said other part is spaced from the hinge axis of the two parts, and the pivotal connection between the link and the rack moves in a trajectory which is non-concentric with respect to the hinge axis, as the rack is displaced by said gear member.

3. A hinge fitting as claimed in Claim 1 or 2 in which the rack is of linear configuration.

4. A hinge fitting as claimed in Claim 1 or 2 in which the rack is of arcuate configura

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. straining the pinion device to move in this manner. At this stage, no movement of the rack occurs. Eventually, the lobe 56A of the cam engages with and seats in concavity 62B and further rotation of the pinion is translated into a turning movement about the pin 50A with consequent displacement of the pin 50B and rotation of the rack. Such movement continues until the lobe 56C engages with, and seats in, the concavity 62A whereupon the rotation of the pinion 30 is translated into turning about the pin 50C with continued turning of the rack by pin 50B and accompanying movement of the pin 50A towards meshing engagement with the rack. As the pin S0A passes cusp 64B, the effective turning point of the pinion becomes pin 50B and as pin 50A enters the aligned intertooth space, the pin 50C moves into registry with the crest 60. The pinion has by then assumed the stable, locking position illustrated in the drawing and for a 1200 rotation of the pinion, the rack has been displaced through one tooth pitch. It will be noted that the curvature of the surfaces 66A, B co-operates with the cam lobes to resist unintended turning of the pinion and that the registry between the crest 60 and the adjacent cam lobe provides a failsafe feature in the event of breakage of the spring loading the pinion radially inwardly. In this event, the cam lobe will engage the crest to overcome the tendency for the pinion to turn due to loading of the backrest plate 10. In a modification of the illustrated embodiment, the cam 54 can be omitted and the pins 50A, B, C may co-operate directly with the profiled aperture 58 as shown in Figure 2. In Figure 2 the path of movement of each pin is indicated by reference numeral 70. Direct engagement between the pins and the profiled aperture is not favoured however because of the increased wear to which the pins are then subject. In another modification, there may be only two pins disposed diametrally opposite each other; three pins are preferred however because the extent of the radial shift or wobble of the pinion device is reduced and the rotational movement per tooth pitch advance is 1200 instead of 1800. It is also within the ambit of the invention to use four or more pins or other intertoothmeshing elements with appropriate modifications of the profiled guide surfaces. As mentioned, the hinge fitting of Figure 1 may be duplicated at each side of the seat in which case the pinion devices 30 will be coupled together by a shaft or the like so that both can be operated by a single handle or lever. Alternatively the mechanism can be provided at one side only with a plain hinge fitting at the other side. Although this type of pinion device described above is preferred because it is self-locking, other types of pinion could be used, e.g. a conventlonal pinion gear, but in that event some means, e.g. a ratchet or clutch device, is necessary for preventing unintended turning of the pinion by the forces acting on the backrest. In another modification, a worm gear may be used in place of the pinion and in this event, a ratchet or clutch device may not be necessary. Although the rack is of semi-circular configuration in the illustrated embodiment, other configurations are possible; for example, the rack may, in some instances, be of generally linear configuration, ie. with its teeth arranged along a straight line. Figures 3 to 5 show another modification of the invention in which like parts are designated by the same reference numerals as in Figure 1. In this embodiment, the rack 20 is circular, the link 24 is somewhat smaller in length and the pivot 14 between the plates 10 and 12 lies within the periphery of the rack 20. The pivot 14 in this case is supported by an additional plate 72 which is secured to the plate 10 so as to sandwich the rack 20 and plate 12 therebetween, and the rack 20 is formed with an arcuate slot 74 concentric with the journal 22 connecting the rack 20 to the plate 12, through which slot the pivot 14 extends. In operation, clockwise turning of the pinion 30 causes anticlockwise turning of rack 20 thus causing pivot 26 to move about journal 22 with consequent displacement of the link 24 and hinging of plate 10 relative to plate 12. WHAT WE CLAIM IS:

1. A hinge fitting comprising first and second parts hingedly connected together and means actuable by a rotary member for effecting angular movement between said parts, said means coupling together said parts in such a way that turning movement of said rotary member is non-linearly related to the relative angular movement between said parts.

tion.

5. A hinge fitting as claimed in Claim 2 in which the rack is of arcuate configuration and is angularly displaceable relative to said one part, the pivotal connection between said link and the rack being spaced from the axis about which the rack is angularly movable.

6. A hinge fitting as claimed in Claim 5 in which the rack is of part-circular configuration and is pivoted to said one part at the centre of curvature of the rack.

7. A hinge fitting as claimed in Claim 2 4, 5 or 6 in which the arrangement is such that when the gear engages one end of the rack, the pivotal connections between the link and the rack and between the link and said other hinge part are substantially aligned with the pivotal connection between the rack and said one hinge part, the latter pivotal connection being located between the former two pivotal connections.

8. A hinge fitting as claimed in Claim 2 in which the rack is of generally circular configuration and the periphery of the rack encompasses the pivotal connection between the two hinge parts.

9. A hinge fitting as claimed in Claim 2 or any one of Claims 3-8 as appendant to Claim 2 in which the gear member comprises at least two parallel elements spaced from the rotary axis of the gear member and cooperable with the rack teeth in such a way that in certain positions of the gear member two of said parallel elements engage fully in the intertooth spaces flanking a tooth of said rack, the gear member being mounted for movement generally perpendicularly to the rack at the position of engagement between the rack and the gear member.

10. A hinge fitting as claimed in Claim 9 in which the gear member comprises three elements spaced 1200 apart at the same radial distance from the rotary axis of the gear member.

11. A hinge fitting substantially as hereinbefore described with reference to, and as shown in, Figures 1 and 2 or Figures 3 to S of the accompanying drawings.