FR2788834A1 - System for retaining the selected angular position of two pieces that rotate relative to one another such as vehicle seat control mechanisms, comprises a spring loaded cam assembly - Google Patents

Abstract

The retention system comprises of slide block (24) mounted on a spring assembly (25) and engaging a first toothed section (6). The toothed section engages the second piece via the same type of engagement means. A cam unit (28) enables the toothed sections to be selectively engaged and disengaged.

Description

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  ANGULAR SOLIDARIZATION DEVICE

  SELECTIVE OF TWO PARTS IN RELATIVE ROTATION

  The present invention relates to a device for selective angular securing of two parts in relative rotation, and more particularly in relative rotation about an axis from a first relative angular position where the two parts are in abutment for a first direction of rotation up to at least a second relative angular position, a ratchet system allowing between said first and second positions a relative movement step by step in the second direction of rotation and preventing relative movement in the first direction of rotation, means being provided for disengaging said ratchet system when the two parts arrive in their second relative angular position in the second direction of rotation so as to allow free relative movement to

  less between the first and second relative angular positions.

  Such devices are known, for example, in the field of supports or armrests for the seat of motor vehicles. These members are in fact generally adjustable to ensure the comfort of the user, and also to be able to be optimally positioned from the point of view of user safety. In what follows, we can assume that the two

  above-mentioned parts are the seat back and, respectively, the support

head or armrest.

  For a headrest, the first relative angular position will, for example, be the most inclined rearward position. From this position, the headrest can be brought forward step by step, the successive notches of the ratchet system imposing the different possible positions. At each step, the headrest is blocked towards

  the rear but can still be oriented further forward.

  When the adjustment stroke is completely covered,

  ie when the headrest has reached its most forward adjustment position - this is the second relative angular position between the backrest and the headrest -, an additional movement forward

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  disengages the ratchet system so that the headrest

  can be brought back to its stop position.

  In the case of an armrest, the first relative angular position can be considered as the lowest position, generally substantially horizontal, and the second position

  relative angular is an upward tilted position. We will see below

  after that the case of the armrest is a little different from that of the headrest. Indeed, the armrest must generally be able to be brought further into a third relative angular position o it is substantially vertical, applied against the seat backrest, and o consequently it does not interfere with the user. Conditions are also imposed for security reasons for unlocking

  the armrest from this third position.

  Various accessories positioning devices of this type exist in the state of the art. These known devices often include, in particular as regards the armrests, a lever or an operating button making it possible to release at will.

  the headrest or armrest to allow its adjustment.

  Document FR-A-2 737 263 also discloses an automatic indexed guidance device for a moving part articulated around an axis on a fixed part. This device uses an oscillating pawl and snap-on elastic means to maintain the pawl in its different functional positions. Such an arrangement has the disadvantage of being relatively difficult to

industrialize and fairly unreliable.

  The present invention aims to overcome these drawbacks.

  More particularly, the purpose of the invention is to provide a device for selective angular securing of two pieces in

  relative rotation whose manufacture is easy and which is inexpensive.

  To this end, the invention relates to a device for selective angular securing of two parts in relative rotation about an axis from a first relative angular position where the two parts are in abutment for a first direction of rotation until at at least a second relative angular position, a ratchet system allowing between said first and second

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  positions relative movement step by step in the second direction of rotation and preventing relative movement in the first direction of rotation, means being provided for disengaging said ratchet system when the two parts arrive in their second relative angular position in the second direction of rotation so as to allow free relative movement at least between the first and second relative angular positions, characterized in that said ratchet system comprises a first toothed sector integral with a first of said two parts, centered on said axis, and a first cam mounted on said first part, a slider mounted sliding on the second part, said slider carrying a second toothed sector capable of cooperating with the first toothed sector, and a cam follower finger, and first elastic means arranged to exert on the slide an effort tending to bring the first and second e geared toothed sectors, the teeth of the first and second toothed sectors being respectively arranged so that, when the first and second toothed sectors are meshed under the action of the first elastic means, the teeth of the first and second sectors block the relative movement in the first direction of rotation but allow the relative movement step by step in the second direction of rotation by allowing the second sector to be pushed away from the first sector against the action of the first elastic means, the first cam being arranged to cooperate with the cam follower finger so that the first and second toothed sectors engage when the two parts come into their first relative position, and do not engage when the two parts come into their second relative position . The device of the invention therefore comprises a sliding ratchet system, easier to produce and more reliable than that of

Prior art.

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  In the case where one of the parts is the backrest of a motor vehicle seat and the other part is an armrest, this can

  be adjusted step by step in inclination from a low position.

  When it reaches its highest adjustment position, the ratchet system disengages and the armrest can be returned to the low position. In a particular embodiment, said first cam comprises a first cam surface which, when the cam follower finger is supported on this first surface under the action of the first elastic means, prevents the second toothed sector from engaging with the first sector, a first exhaust means which, when the two parts are in their first relative angular position, allows the cam follower finger to escape from the first cam surface, a first engagement means which, when the two parts are in their second relative angular position, allows the cam follower finger to come into contact with the first cam surface when the relative movement of the two parts passes from the

  second to first direction of rotation.

  More particularly, the first exhaust means may comprise an interruption of the first cam surface at the location where the cam follower finger is located when the two

  parts are in their first relative angular position.

  Also in a particular embodiment, the first cam is mounted to oscillate on said first part, and the first engagement means comprise a second cam surface arranged to cooperate with the cam follower finger to cause the cam to oscillate against the action of second

elastic means.

  Even more particularly, the first and the second cam surfaces can meet at a first end of the first cam where the cam follower finger is located when the two parts are in their second relative angular position, so that, when the two parts approach step by step from their second relative angular position in the second direction of rotation, the first cam oscillates in a first direction due to

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  the action of the cam follower finger on the second cam surface, then oscillates in the second direction under the action of the second elastic means when the cam follower finger reaches said end of the first cam, and the follower finger s' engages on the first cam surface when the relative movement of the two parts is reversed and the two parts move freely,

  initially at least in the first direction of rotation.

  In this case, said first cam may be formed of an elastic tongue, the first and second cam surfaces joining at a free end of the tongue and the other end of the tongue being integral with the first part, the second

  elastic means being constituted by the tongue itself.

  Such an arrangement makes it possible to produce the ratchet system

particularly simply.

  More particularly, a stop can be provided at the free end of said elastic tongue to limit its movement in the second direction of oscillation when the cam follower finger is in contact with the first cam surface under the action of the first

elastic means.

  In a particular embodiment, the two parts are also freely movable in relative rotation between the second relative angular position and a third relative angular position located beyond the second relative angular position relative to the first relative angular position, unlockable blocking means being provided for blocking the relative movement between the two parts when they are in their third position

relative angular.

  In the case of an armrest, the latter can thus be brought into

  vertical position and locked in this position.

  Said locking means may comprise the cam follower finger and a recess formed in a member integral with the first part at the location where the cam follower finger is located when the two parts are in their third relative angular position, so that the cam follower finger enters the recess under the action of the first elastic means

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  when the two pieces arrive in their third position

relative angular.

  A third cam surface can also be formed on a member integral with the first part, arranged to cooperate with the cam follower finger to retain the movement of the slide under the action of the first elastic means, and prevent the engagement of the two. toothed sectors when the two parts are in a relative angular position between their second and their third relative angular position coming from the second

relative angular position.

  More particularly, means for unlocking the means for blocking the relative movement between the two parts when they are in their third relative angular position, may comprise the inclined flank of said recess situated on the side of the recess opposite the third cam surface, arranged to cooperate with the cam follower finger to push the slide against the action of the first elastic means when the relative movement between the two parts is continued beyond their third relative angular position against the action of third elastic means, and inhibiting means to prevent the cam follower finger from returning to the recess when the two parts

  are brought back to their third relative angular position.

  In the case of an armrest, one can thus unlock it from its high position by bringing it back against the action of a spring, and then bring it back to its lowest position before

  adjust its position.

  More particularly, the inhibition means may comprise a second oscillating cam arranged to be pushed back against the action of fourth elastic means by the cam follower finger when the latter cooperates with the inclined flank of the recess, and to return to the opening. of the recess under the action of the fourth elastic means

  when the cam follower is pulled out of the recess.

  Even more particularly, the second oscillating cam may comprise a fourth cam surface facing the side opposite the recess to cooperate with the cam follower finger when the two parts are in a relative angular position.

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  between their second and their third relative angular position from the third relative angular position to retain the movement of the slide under the action of the first elastic means, and prevent the meshing of the two toothed sectors. Also in a particular embodiment, the fourth elastic means comprise a helical spring whose axis is disposed substantially in an arc centered on the relative axis of rotation of the two parts, a spring each end of which

  is supported on a stop integral with one of the two parts.

  A particular embodiment of the invention will now be described, by way of nonlimiting example, with reference to the appended schematic drawings in which - FIG. 1 is a top view of a device according to the present invention; - Figure 2 is a top view of the cam assembly of this device; - Figure 3 is a bottom view of the slide of this device; - Figure 4 is a bottom view of the toothed wheel of this device; - Figure 5 is a top view of certain other elements of this device; and - Figures 6a to 6e are partial top views

  illustrating the device in several phases of its operation.

  FIG. 1 shows a frame 1 of an armrest for a motor vehicle seat provided with the device according to the invention and intended to be covered with a trim of known type. This frame is rotatably mounted around a tubular axis 2 secured to the seat back. This axis 2 projects from the armrest frame 1 on the side

  opposite the point of view of Figure 1.

  It will be considered in what follows that the axis 2 and the organs which are integral therewith are fixed while the other organs of the

  device are movable around the axis.

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  Among the parts integral with the axis 2 is first of all a toothed wheel 3 formed essentially of a metal disc having a central circular orifice 4 arranged to receive the axis 2. Diametrically opposite with respect to the axis, the toothed wheel 3 forms two radial recesses 5 opening into the orifice 4. The toothed wheel 3 has on a part of its periphery a toothing 6. The teeth of the toothing 6 are inclined so that the toothed wheel 3 forms a ratchet with a corresponding body which

will be described below.

  A rod 7 passes through two holes 8 drilled diametrically opposite in the wall of the axis 2. This rod 7 protrudes radially from the axis 2 so that its ends engage in the recesses 5 when the toothed wheel 3 is mounted on the axis 2. Thus, the toothed wheel 3 is integral with the axis 2 and

is therefore fixed.

  A set 9 of cams generally in the form of a disc is also mounted integral with the axis 2 by means of the toothed wheel 3. The assembly 9 is here made in one piece from molded synthetic material. Cams are generally coaxial with

Axis 2.

  The assembly 9 essentially comprises two groups of cams and 11, each arranged circumferentially around the axis 2. The group of cams 10 is formed on an elastic tongue 12, one end of which is connected to the assembly 9. The group of cams 11 is formed partly directly on the assembly 9 and partly on an elastic tongue 13, one end of which is connected to the assembly 9 The elastic tongue 12 supports at its free end, by means of a stiffening web 14 perpendicular to the axis 2, a first convex cylindrical cam surface 15 oriented towards the outside with respect to the axis 2 and a second cam surface

  concave cylindrical 16 oriented inward relative to axis 2.

  The two cam surfaces 15 and 16 meet at the free end of the assembly 9 to form a beak 17 inclined radially towards the axis 2. On the side of the cam surfaces 15 and 16 opposite the beak 17,

  these surfaces form an interruption 18.

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  The cam group 11 firstly comprises a third convex cylindrical cam surface 19 coaxial with the axis 2. This cam surface 19 is located, on the side of the cam group 10, in

  the extension of the cam surfaces 15 and 16.

  Opposite the cam surfaces 15 and 16, the third cam surface 19 ends in a recess 20 whose concavity is directed towards the outside, opposite the axis 2. This recess 20 comprises, side of the cam surface 19, a substantially radial side 21, and on the opposite side a side 22 inclined in

The other direction.

  The elastic tongue 13 also forms, on its outside, a fourth convex cylindrical cam surface 23 outside by

in relation to axis 2.

  If we now refer to Figures 1 and 3 in particular, we see a slide 24 movable in a substantially radial direction relative to the axis 2. This slide is pressed towards the axis 2 by a helical spring 25 in support on the one hand on an external bearing surface 26 of the slide 24 and on the other hand on a bearing surface

27 of frame 1.

  As can be seen in FIG. 3, the slide 24 has on its underside a toothed sector comprising a toothing 27 capable of cooperating with the toothing 6 of the toothed wheel 3. The teeth of the toothing 27 are inclined so that the gear wheel

  3 forms a pawl with the slide 24.

  The slide 24 further comprises, on this same lower face, a cam follower finger 28 arranged to cooperate with

the aforementioned cam surfaces.

  When they are mounted on the axis 2, the toothed wheel 3 and the set 9 of cams are housed in a cylindrical housing 29 of the frame 1. The slider 24 is arranged to slide in a groove 30 of the frame 1 opening radially into the housing

cylindrical 29.

  An annular housing 31 is formed at the bottom of the cylindrical housing 29, coaxial with this housing 29, and receives a helical spring 32. The helical spring 32 abuts on the one hand on a

-........-.- I ..

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  end surface 33 of the housing 32 and on the other hand on a projection

34 integral with axis 2.

  We see in Figures 1 and 6a to 6e the operation of the

  device which has just been described.

Claims (11)

  1 - Device for selective angular securing of two parts in relative rotation about an axis from a first relative angular position o the two parts are in abutment for a first direction of rotation up to at least a second relative angular position, a system with ratchet allowing between said first and second positions a relative movement step by step in the second direction of rotation and preventing relative movement in the first direction of rotation, means being provided for disengaging said ratchet system when the two parts arrive in their second relative angular position in the second direction of rotation so as to allow free relative movement at least between the first and second relative angular positions, characterized in that said ratchet system comprises a first toothed sector integral with a first of said two parts, centered on said axis, and a first cam mon tée on said first part, a slider mounted sliding on the second part, said slider carrying a second toothed sector capable of cooperating with the first toothed sector, and a cam follower finger, and first elastic means arranged to exert on the slider a effort tending to bring the first and second toothed sectors into meshing, the teeth of the first and second toothed sectors being respectively arranged so that, when the first and second toothed sectors are meshing under the action of the first elastic means, the teeth of the first and second sectors block relative movement in the first direction of rotation but allow the relative movement step by step in the second direction of rotation by allowing the second sector to be pushed away from the first sector against the action of first elastic means, 12 2788834   the first cam being arranged to cooperate with the cam follower finger so that the first and second toothed sectors mesh when the two parts come into their first relative position, and do not mesh when the two parts come into their second relative position. - 2 - Device according to claim 1, wherein said first cam comprises a first cam surface which, when the cam follower finger is supported on this first surface under the action of the first elastic means, prevents the second toothed sector from come to mesh with the first sector, a first exhaust means which, when the two parts are in their first relative angular position, allows the cam follower finger to escape from the first cam surface, a first engagement means which , when the two parts are in their second relative angular position, allows the cam follower finger to come into contact with the first cam surface when the relative movement of the two parts passes from the   second to first direction of rotation.   3 - Device according to claim 2, wherein the first exhaust means comprises an interruption of the first cam surface at the location where the cam follower finger is located when the two parts are in their first position relative angular.   4 - Device according to any one of claims 2 and 3,   wherein the first cam is mounted to oscillate on said first part, and the first engagement means comprise a second cam surface arranged to cooperate with the cam follower finger to cause the oscillation of the   first cam against the action of second elastic means.   - Device according to claim 4, wherein the first and second cam surfaces meet at a first ext'éiIté of the first cam o is the cam follower finger when the two parts are in their second relative angular position, the so that when the two pieces don't come close to 13 2788834   not from their second relative angular position in the second direction of rotation, the first cam oscillates in a first direction due to the action of the cam follower finger on the second cam surface, then oscillates in the second direction under the action second elastic means when the cam follower finger reaches said end of the first cam, and the follower finger engages on the first cam surface when the relative movement of the two parts is reversed and the two parts move freely, at least initially, in the first direction of rotation.   6 - Device according to claim 5, wherein said first cam is formed of an elastic tongue, the first and second cam surfaces joining at a free end of the tongue and the other end of the tongue being integral with the first piece, the second elastic means being constituted by the tongue itself.   7 - Device according to claim 6, wherein a stop is provided at the free end of said elastic tongue to limit its movement in the second direction of oscillation when the cam follower finger is supported on the first cam surface under   the action of the first elastic means.   8 - Device according to any one of claims I to 7,   in which the two parts are also freely movable in relative rotation between the second relative angular position and a third relative angular position situated beyond the second relative angular position relative to the first relative angular position, unlockable blocking means being designed to block relative movement between the two parts   when they are in their third relative angular position.   9 - Device according to claims 8, wherein said   locking means comprise the cam follower finger and a recess formed in a member integral with the first part at the location where the cam follower finger is located when the two parts are in their third relative angular position, so that the finger cam follower enters the recess under the action of the first elastic means when the two parts   arrive in their third relative angular position. 14 2788834   - Device according to claim 9, in which a third cam surface is formed on a member integral with the first part, arranged to cooperate with the cam follower finger to retain the movement of the slide under the action of the first elastic means, and prevent the engagement of the two toothed sectors when the two parts are in a relative angular position between their second and their third relative angular position coming from the second relative angular position.   11 - Device according to any one of claims 9 and   , in which means for unlocking means for blocking the relative movement between the two parts when they are in their third relative angular position, comprise the inclined flank of said recess located on the side of the recess opposite the third cam surface, arranged for cooperate with the cam follower finger to push the slide against the action of the first elastic means when the relative movement between the two parts is continued beyond their third relative angular position against the action of third elastic means, and means to inhibit the cam follower finger from returning to the recess when the two parts are brought back   towards their third relative angular position.   12 - Device according to claim 11, in which the inhibition means comprise a second oscillating cam arranged to be pushed against the action of fourth elastic means by the cam follower finger when the latter cooperates with the inclined flank of the recess, and to return to the opening of the recess under the action of the fourth elastic means   when the cam follower is pulled out of the recess.   13 - Device according to claim 12, wherein the second oscillating cam has a fourth cam surface facing the side opposite the recess to cooperate with the cam follower finger when the two parts are in a relative angular position between their second and their third relative angular position coming from the third relative angular position to retain the movement of the slide under -I'l 2788834   the action of the first elastic means, and preventing the entanglement of the two toothed sectors.   14 - Device according to any one of claims 12 and   13, in which the fourth elastic means comprise a helical spring whose axis is disposed substantially in an arc centered on the relative axis of rotation of the two parts, a spring each end of which bears on a stop integral with one of the two rooms.