GB2273042A

GB2273042A - Seat position adjustment mechanism

Info

Publication number: GB2273042A
Application number: GB9224826A
Authority: GB
Inventors: John Christopher Howard; David Charles Blackmore
Original assignee: KAB Seating Ltd
Current assignee: KAB Seating Ltd
Priority date: 1992-11-26
Filing date: 1992-11-26
Publication date: 1994-06-08
Anticipated expiration: 2012-11-26
Also published as: GB2301620A; GB9224826D0; GB2273042B; GB2301620B; GB9614381D0

Abstract

A seat position adjustment mechanism suitable for enabling the driver's seat 1 in the cab of a mechanical digger to rotate and to move backwards and forwards is described. The seat adjustment means includes a disengagement mechanism for disengaging a turntable from the pedestal 3 of the seat so as to enable rotation of the seat relative to the pedestal. A further disengagement mechanism is effective to allow longitudinal displacement of the seat relative to the pedestal. A lever 13 is arranged to operate a mechanical linkage such that continued movement of the lever in a single direction enables firstly rotational movement of the seat relative to the pedestal and subsequently movement of the seat along the longitudinal axis of the digger. <IMAGE>

Description

SEAT POSITION ADJUSTMENT MECHANISM This invention relates to seat position adjustment mechanisms. The invention has particular relevance to seat position adjustment mechanisms for vehicle seats, in particular seats for the cabs of mechanical diggers.

In mechanical diggers, having typically a grab at the back of the vehicle and a bucket at the front of the vehicle, there is a requirement for the driver's seat to be capable of rotating through 1800 so as to enable the driver to face either the front or the rear of the vehicle. In view of the dimensions of the cab of such a vehicle, it is also necessary for the seat to be able to move backwards and forwards along the longitudinal axis of the vehicle, in order to enable the driver to achieve a suitable position for operating the grab at the rear of the vehicle or the bucket at the front of the vehicle.

Known seat position adjustment mechanisms for use in mechanical diggers include two separate seat position adjustment mechanisms to facilitate the required rotational and longitudinal seat movements. The first seat position adjustment mechanism includes an arrangement effective to disengage a turntable incorporated in the seat from the framework of the seat, so as to enable rotation of the seat relative to the framework of the seat. The second seat adjustment mechanism includes a further disengagement arrangement effective to disengage a pair of runners incorporated in the seat from a pair of slide rails attached to the framework of the seat, so as to allow the driver to move the seat backwards and forwards along the longitudinal axis of the vehicle. The two disengagement arrangements may be operated by two separate levers.Alternatively, the two disengagement arrangements may be operated by a single lever which is operated in the first direction to achieve disengagement of the turntable and enable rotation of the seat, and a second direction to disengage the runners from the slide rails so as to enable the driver to move the seat backwards and forwards. Such known seat position adjustment mechanisms have the disadvantage, however, that rotation and longitudinal movement of the seat --can only be achieved in two discrete movements. This can be dangerous where, as is often the case, the mechanical digger is positioned on a steep incline, as the two stage adjustment of the driver's position is necessarily quite slow.

It is an object of the present invention to provide a seat position adjustment mechanism effective to enable the rotational and longitudinal displacement of a seat wherein the above disadvantages are avoided.

According to a first aspect of the present invention there is provided a seat position adjustment mechanism including: a first disengagement mechanism for disengaging a turntable from the framework of the seat so as to enable rotation of a seat relative to the support for the seat; a further disengagement mechanism effective to allow longitudinal displacement of the seat relative to the support for the seat; a lever means; and a mechanical linkage connecting the lever means to the first and second disengagement means such that continued movement of the lever means in a single direction causes first one of the first and further disengagement means, and then the other of the first and further disengagement means to operate.

Thus, in a seat incorporating a seat position adjustment mechanism in accordance with the invention, rotational and longitudinal displacement of the seat may be achieved in a single arcuate movement.

According to a second aspect of the present invention there is provided a disengagement mechanism for disengaging a turntable from the framework of a seat, comprising a shaft and a pecker arrangement mounted on the shaft, the pecker arrangement comprising a bearingless roller mounted on a pivot, and operating means for rotating the shaft, thereby disengaging the pecker arrangement from the slot.

By the use of such a disengagement mechanism, the use of grease is avoided, avoiding dirt build-up at this point.

Two seat position adjustment mechanisms in accordance with embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a schematic front view of a vehicle seat showing the first embodiment of a seat position adjustment mechanism in accordance with the invention; Figure 2 is a side view of part of the seat of Figure 1, on a larger scale to the view of Figure 1; Figure 3 is a figure corresponding to part of the view of Figure 1 on the same scale as that of Figure 2, showing part of the seat position adjustment mechanism in more detail; Figure 4 shows a side view of part of the mechanism of Figures 1 and 2, seen in the direction of the Arrow IV in Figures 1 and 3, the view being on a larger scale to that of Figure 1;; Figure 5 is a view corresponding to that of Figure 4 showing more of the mechanism in a number of different operational positions; Figure 6 is a cross-section along the line VI of Figure 7, showing the rotational displacement disengagement mechanism; Figure 7 is a cross-section along the line VII-VII of Figure 6 showing a further aspect of the rotational displacement disengagement mechanism; Figure 8 is a plan view along the direction VIII of Figure 1, showing the longitudinal displacement disengagement mechanism; Figure 9 is a part plan view along the direction of the Arrow IX in Figure 1, showing some details of the longitudinal displacement disengagement mechanism; Figure 10 is a schematic diagram of the second embodiment of the seat position adjustment mechanism in accordance with the invention in a first operational position;; Figure 11 is a view corresponding to the view of Figure 10, with the mechanism in a second operational position; and Figure 12 is a view corresponding to the view of Figure 10 with the mechanism in a third operational position.

Turning firstly to Figure 1, the seat adjustment mechanism to be described is intended for use in the driver seat of the cab of a mechanical digger. The seat 1, only part of which is shown, is mounted on a pedestal 3, the seat 1 being supported by a seat suspension system, indicated generally as 5, of conventional form.

The seat position adjustment mechanism, for enabling the seat 1 to rotate about the pedestal 3, and move backwards and forwards along the longitudinal axis of the vehicle, is indicated generally as 7, and is located primarily between the seat suspension system 5 and the pedestal 3.

The seat also includes a mechanism of conventional form, indicated generally as 9 for adjusting the inclination of the back of the seat 1 relative to the base of the seat, and a conventional mechanism 11 for adjusting the height of the seat.

Turning now also to Figures 2 and 3, the seat adjustment mechanism 7 is arranged to be manually operated by an operating lever 13. The lever 13 has a knob 15 at its upper end which is located at the side of the seat 1.

At the lower end of the lever 15 a portion 17 which extends substantially at right angles to the upper end of the lever 13, through an aperture 19 in the seat framework 21 and across the adjustment mechanism 7, the lever 13 being mounted on the framework 21 such that it is able to rotate within the aperture 19.

Turning now also to Figure 4, the lever 13 is welded to a cam 23. Forward and rear stop members 25,27 are provided to limit the rotation of the lever 13 due to the engagement of the cam 23 with the stop members 25,27.

Turning now particularly to Figures 2,3 and 5, at the lowermost point of the cam 23, there is mounted a roller 29. This is arranged to run in a channel 31 fixed to the right hand side of the seat frame as viewed in Figure 1, extending along the lateral edge of the frame as best seen in Figure 2. At either end of the channel 31 there is provided a respective pivoted lever 33,35; The lower ends of the lever 33,35 are joined by a link 37, this completing a parallelogram configuration linkage 29,33,37,35.

As can best be seen in Figures 6 and 7, mounted through the forwardmost lever 33 is a shaft 39 which extends under the seat framework. The shaft 39 carries a pivot 41, which in turn carries a bearingless case hardened roller 43, a circlip 45 at the end of the pivot 41 locating the roller 43 on the pivot 41. Also located under the seat framework is a circular plate 47 attached to the pedestal 3. A peripheral groove 49 is formed in the plate 47, the groove 49 together with an opposing groove 51 formed in a turntable plate 53 attached to the seat framework locating a roller race 55. The pivot 41 is spring-loaded by a spring 57 into a position in which the roller 43 passes through a slot 58 in the plate 47 to locate in one of two peripheral slots 59,61 formed through the turntable 53, so as to be effective to lock the turntable 53 onto the plate 47.

Turning now particularly to Figure 8, the longitudinal seat movement disengagement mechanism includes two cams 65 and 67 each pivoted to a respective slide rail 69,71 extending longitudinally and positioned towards the two lateral edges of the mechanism 7. Each cam 65,67 is spring loaded by a respective spring 73,75 as shown in Figure 1, into a position in which a nose portion of each cam 65,67 is effective to lock a respective longitudinally extending runner 77,79 of the seat 1 into the corresponding slide rail 69 or 71. Padded stops 85,86 are carried by the right hand slide rail 71 as best seen in Figures 8 and 9, these being effective to limit the travel of the slide rails 69,71.

Attached to the portion 17 of the lever 13 which extends through the mechanism 7, is an abutment in the form of a roller 80 mounted on a pivot 81. The abutment 80,81 is springloaded by a spring 82 into a position away from the left hand cam 65. On the continued forwards rotation of the lever 13 within the aperture 19 in the framework 21 however, the abutment 80,81 will rotate with the portion 17 of the lever 13, until the abutment 80,81 eventually contacts the left-hand cam 65, moving the cam 65 away from the position at which the nose of the cam 65 contacts the seat runner 77. A corresponding movement of the cam 67 at the right-hand side of the mechanism is produced by a rod 83 which connects the two cams 65,67.

Thus on rotation of the lever 13 in a forwards direction from the rearmost position of the lever 13, which is defined by the front uppermost surface of the cam 23 contacting the front stop 25, the cam 23 will rotate with the lever 13 until the roller 29 mounted on the cam 23 has moved to the bottom surface of the channel 31.

Continued rotation of the lever 13, will cause the roller 29 to depress the link 37, thus causing rotation of the levers 33,35. Rotation of the front lever 33 will cause a corresponding rotation of the shaft 39, this leading to the roller 43 disengaging from the slot 59 or 61 in the turntable 53, and thus disengaging the turntable 53 from the fixed plate 47. The operator is then able to rotate the seat 1 through 1800, the roller 43 running along the perimeter of the underside of the turntable 53, until the roller 43 locates into the diametrically opposed slot 61 formed through the turntable 53, thus again locking the turntable 53 on to the plate 47.

As the lever 13 further rotates in the forward direction, the portion 17 of the lever will cause the abutment 81,80 eventually to engage the cam 67, disengaging the cam 67 from the seat runner 69, the movement of the cam 67 being transmitted through the rod 83 so as to cause the right-hand cam 65 to disengage the right-hand seat runner from the right-hand slide rail 71. Thus an operator will be able to move the seat backwards or forwards as required. It will be seen from Figure 5, that as the slide rails 69,71 move longitudinally with respect to the pedestal 3, the roller 29 carried by the cam 23 will run down the channel 31 with the movement of the seat.

It will be appreciated that a skilled operator will be able to combine the rotational and longitudinal motion of the seat, so as to achieve a continuous arcuate motion.

The padded stops 85,86 carried by the right-hand slide rail will be effective to cause damping of the longitudinal movement of the seat, ensuring that there are no jolts and extending the lifetime of the adjustment mechanism as well as providing more comfort to the operator.

It is found that by using the case-hardened roller 43 to form a pecker mechanism for the turntable disengagement mechanism, no grease is needed in the turntable release mechanism, thus avoiding dirt build-up at this point.

It will be appreciated that the use of such a roller arrangement as a pecker mechanism for a turntable disengagement mechanism, will find application in other seat position adjustment mechanisms, other than the mechanism described herebefore.

Turning now to the second embodiment as illustrated in Figures 10, 11 and 12, this is an adaptation of the first embodiment and thus only part of the mechanism is illustrated, with components which are also included in the first embodiment being referred to. The lever 13 of the first embodiment is replaced by a lever 101 which is pivoted for rotation about a pivot point 103 on the seat framework 21, the rotation of the lever 101 being in the opposite sense to the lever 13 of the first embodiment, i.e. the lever 101 is arranged for rotation in a rearward direction. A cam 105 is arranged to rotate with the lever 101, the total rotation of the lever 101 0 being limited to 60 by a peg 107 which engages in a slot 109 in the cam 105.

A wire 111 is attached to the cam 105, this wire 111 being connected through a linkage indicated generally as 113 to a turntable release pawl 115. The pawl 115 is connected to a turntable release mechanism of the same general form as described in relation to the first embodiment.

Towards an edge of the cam 105 remote from the lever 101, there is formed a slot 117, through which is threaded bent over end portion 118 of a wire 119. The end of the wire 119 remote from the cam 105 is attached to a longitudinal seat movement disengagement mechanism of the form described in relation to the first mechanism.

Thus, as shown in Figure 10, when the lever 101 is in its forwardmost position, as defined by the abutment of the rear surface of the slot 109 on the peg 107, both the turntable and the slide rails are in their latched configurations. As the lever 101 is rotated in a backwards sense to an upright position, as depicted in Figure 11, the point of the attachment of the wire 111 to the cam 105 moves backwards, pulling the wire 111 and causing the pawl 115 to rotate. This leads the turntable disengagement mechanism to operate as in the first embodiment, releasing the roller 43 from the slot 59 or 61 in the plate 47 and thus enabling the turntable 53 to rotate relative to the plate 47.

As the lever 101 rotates from the position shown in Figure 10, towards the position shown in Figure 11, the end of the wire 111 is pulled until it reaches approximately top dead centre of the cam 105 at which point continued rotation of the lever 101 to the position shown in Figure 12, causes the wire 119 to be pulled by the rotating cam 105, this causing disengagement of the longitudinal seat movement latching arrangement as described above in respect of the first embodiment.

It will be appreciated that in both embodiments, rotation of the operating lever 33 or 101 in a single direction causes initially the turntable disengagement mechanism to operate, and subsequently the longitudinal displacement disengagement mechanism to operate backwards and forwards with respect to the framework.

This enables a skilled operator to adjust the position of the seat 1 in a continuous arc, thus saving time as the operator can move between the two required seat positions in a single movement. It will be seen that in both mechanisms whatever the travel of the lever, the same camming action is produced.

It will also be appreciated that whilst normally rotational movement of the seat will be required before longitudinal displacement of the seat, in some circumstances it may be required to displace the seat in the longitudinal direction before the seat is rotated.

A seat position adjustment mechanism in accordance with the invention can be designed to accommodate such a seat movement.

Claims

1. A seat position adjustment mechanism including a first disengagement mechanism for disengaging a turntable from the framework of the seat so as to enable rotation of a seat relative to the support for the seat; a further disengagement mechanism effective to allow longitudinal displacement of the seat relative to the support for the seat; a lever means; and a mechanical linkage connecting the lever means to the first and second disengagement means such that continued movement of the lever means in a single direction causes first one of the first and further disengagement means, and then the second of the first and further disengagement means to operate.

2. A seat position adjustment mechanism according to claim 1 in which the first disengagement mechanism comprises a shaft and a pecker arrangement mounted on the shaft, the pecker arrangement being effective to engage a slot in the turntable thereby preventing rotation of the turntable, movement of the lever means causing rotation of the shaft thereby disengaging the pecker arrangement from the slot.

3. A seat position adjustment mechanism according to claim 2 in which the pecker arrangement comprises a bearingless roller mounted on a pivot.

4. A seat position adjustment mechanism according to claim 3 in which the roller is made of case-hardened metal.

5. A seat position adjustment mechanism according to any one of claims 2 to 4, in which the mechanical linkage includes a cam means arranged for rotation with the lever means, the cam means being effective to cause rotation of the shaft, irrespective of the longitudinal position of the seat.

6. A seat adjustment mechanism according to claim 5 in which the cam means includes a sliding means which slides in a channel on longitudinal displacement of the seat, rotation of the cam means being effective to cause the sliding means to engage a moveable linkage effective to cause rotation of the shaft.

7. A seat position adjustment mechanism according to any one of the preceding claims, in which the disengagement mechanism effective to allow longitudinal displacement of the seat comprises a locking means having a locking position in which it is effective to lock part of the seat in the seat framework, and means effective to rotate with rotation of the lever thereby to displace the locking means from the locking position.

8. A seat position adjustment means according to claim 7 in which the means effective to rotate is attached to a portion of the lever means.

9. A seat position adjustment mechanism according to any one of the preceding claims including cushioned stop members for limiting the longitudinal displacement of the seat relative to the support for the seat.

10. A seat position adjustment mechanism according to any one of the preceding claims, in which the mechanical linkage includes a first mechanical linkage connected to the turntable disengagement means, and a second mechanical linkage connected to the- longitudinal displacement means, and a rotatable cam means which rotates with the lever means and is effective to successively engage first one and then the other of the first and second mechanical linkages means on continued rotation of the lever means.

11. A seat position adjustment mechanism according to claim 10, in which one of the first and second mechanical linkages is connected to the rotatable cam means, and the other of the first and second mechanical linkages passes through a slot in the cam means, the rotatable cam means being such that on initial rotation of the lever means said one mechanical linkage operates the disengagement means to which it is connected, and on further rotation of the lever means, the second mechanical linkage moves within the slot to a position in which yet further rotation of the cam means causes the second mechanical linkage to operate the disengagement means to which it is connected.

12. A seat position adjust mechanism substantially as herein before described with reference to Figures 1 to 9, or Figures 10 to 12 of the accompanying drawings.

13. A seat including a seat position adjustment mechanism according to any one of the preceding claims.

14. A disengagement mechanism for disengaging a turntable from the framework of a seat, comprising a shaft and a pecker arrangement mounted on the shaft, the pecker arrangement comprising a bearingless roller mounted on a pivot, and operating means for rotating the shaft, thereby disengaging the pecker arrangement from the slot.

15. A disengagement mechanism according to claim 14, in which the roller is made of case-hardened metal.

16. A disengagement mechanism for disengaging a turntable from the framework of a seat, substantially as hereinbefore described with reference to Figures 1,3,6 and 7 of the accompanying Figures.