DEVICE FOR ADJUSTMENT OF A VEHICLE SEAT AND A BASE FRAME FOR A VEHICLE SEAT

Abstract: In an arrangement for a seat (2) in a vehicle, the seat is movable in a longitudinal direction along a plane (33) which slopes relative to the horizontal plane. The subframe of the seat (2) consists of devices (30, 31) fastened respectively to the vehicle and to the seat, which devices consist of two substantially similar triangular supporting frames. Resetting between a predetermined driving position and a likewise predetermined resting position is made possible by a control device (16) which is fastened to the device (30) which is itself fastened to the vehicle, which control device cooperates with a locking device fastened to the seat so that during a relocating movement between forward and rear positions of the seat the locking device (17) becomes free from at least one locking position between the vehicle seat and the device (30) fastened to the vehicle.

Description: Device for adjustment of a vehicle seat, and base frame for a vehicle seat The present invention relates to an arrangement according to the preamble to patent claim 1 and a subframe according to the preamble to patent claim 14. State of the art A generally known arrangement is for vehicle seats, particularly driving seats, to be movable in the longitudinal direction in order to make convenient positioning possible for the seat user and/or create more clear space in the interior of the vehicle. In such cases the seat is usually mounted on longitudinal rails situated in a plane which either slopes somewhat upwards in the forward direction of the vehicle or substantially horizontally. This consequently makes it possible to move the seat along the corresponding plane. Such an arrangement does limit, however, the possibility of easily climbing into and out of the vehicle and getting into and out of the vehicle seat, particularly in vehicles of the truck and bus type. Operating the seat securing mechanism for manual setting of the seat in the longitudinal direction also involves control action during the whole setting movement and often entails one or more extra setting movements before the desired securing position is reached. Brief description of the invention The object of the present invention is to provide a seat arrangement that manifestly reduces the abovementioned disadvantages of the state of the art. The invention aims at seat control which, particularly in truck cabs, makes it easy to reset the seat between a predetermined driving position and a likewise predetermined resting position not intended to be a driving position. The solution has also to make possible a simple form of control mechanism with simple and inexpensive components without having to disregard the safety requirement of reliable securing of the seat. To this end, the invention is distinguished by what is indicated in the characterising part of patent claim 1. The features therein indicated makes it possible for the seat to be provided with a longitudinal relocating movement between a forward (driving) position and a rear (resting) position by easy manual operation of a control which acts upon the seat locking device. Rail mechanisms of standard types which are simple, inexpensive but well-proven from the safety point of view can be used for the purpose. The co-operation according to the invention between control device and locking device also makes it possible to reset the seat quickly and safely between preselected forward and rear positions. This solution is particularly advantageous in the case of seats of the type which can be relocated along a plane which slopes downwards in the forward direction of the vehicle. Such seats are used with advantage in vehicles of the truck and bus type which are entered by climbing and in which it is possible to sit down in the seat from an almost standing position. In an advantageous embodiment of the invention, the seat can be moved rearwards with the assistance of a first force to a rear (resting) position. This makes it possible for a person sitting in the seat to cause it to move to a rear position by simply lightening his weight on the seat and by operating manually the control which acts upon the securing mechanism. In another embodiment, the seat can be moved forwards, i.e. from the rear position to a forward (driving) position, against the action of a second force. This means that in the case of seats of the aforesaid type which can be moved along a plane which slopes downwards in the forward direction of the vehicle, the movement can take place against the action of the second force so that when a person sits on the seat while it is at an upper resting position the seat will automatically, by a controlled movement, assume a driving position. Brief description of the drawings A preferred embodiment of the invention is described below with reference to the attached drawings, in which: Figure 1 shows schematically a side view of a vehicle cab with a seat arrangement according to the invention, Figure 2 shows a perspective view of a seat subframe according to the invention, and Figure 3 shows a schematic arrangement according to the invention for mutual locking of the subframe components. Description of an embodiment A truck cab 1 is depicted schematically in Figure 1. A driver's area contains a driving seat 2 with a subframe 3 which is fastened to the cab floor 4. The seat 2 can be moved in the longitudinal direction of the vehicle from a forward (driving) position 5 to a rear (resting) position 6 which is not intended to be used when the vehicle is being driven. Figure 1 shows only the subframe 3 in the resting position, but it is implicit that when moving to the rear position 6 the subframe 3 is accompanied by the seat 2 with its frame 35. A pedal set 8, a steering wheel 9 and an instrument panel 10 are situated in a conventional manner in front of the seat. A gear lever 11 and a lever 23 forming part of a securing device 15 (depicted in Figures 2 and 3) according to the invention are situated to the side of the seat. An engine cover 12 also protrudes into the cab and to some extent separates the driving side from the passenger side. The subframe 3 is composed advantageously of two substantially similar elements 30,31, each of which has a triangular shape in the vertical plane (see Figure 2). Each element is composed of two triangular sideplates whose sides, which are short catheti, are joined together by an endplate 38 and, at the opposite end, by the corner sections of an angle plate 39. The underside of the element 30, which is a cathetus, is intended to be fastened to the vehicle floor, advantageously by undepicted screws or bolted connections. The hypotenuse side of the element 30 bears a rail device 32a in the form of a rail on each triangular sideplate. The rail device 32a forms a plane 33 which slopes relative to the horizontal plane and which is represented in Figure 1 by a chain-dotted line. The subframe 3 and its elements 30,31 are so arranged that the sloping plane 33 slopes downwards in the forward direction of the vehicle. The hypotenuse side of the upper element 31 correspondingly bears a rail device 32b for cooperation with the rail device 32a of the lower element 30. The top of the upper element 31 supports a rail device 32c (depicted in Figure 1) for co-operation with a corresponding rail device on the underside of the frame 35. Said co-operation makes a longitudinal relocating movement possible along the horizontal plane 34 formed by these rail devices, which is represented in Figure 1 by a chain-dotted line. All the rail devices 32a, 32b and 32c are of a conventional standard type which has toothed recesses for locking in various positions at will and which conform to stringent safety requirements but are described in no further detail here. Figure 3 shows schematically the rail devices 32a,32b with roller devices 27 for easy frictionless longitudinal relocating movement between the elements 30,31. A return spring 40, advantageously in the form of a gas spring as depicted in Figure 2, is arranged between the forward end portion of the lower element 30 (as seen in the forward direction of the vehicle) and the rear end portion of the upper element 31, preferably in a longitudinal symmetry plane between their angle plates 39. When the upper element 31 is in the forward end position 5 (depicted in Figures 1 and 2) relative to the lower element 30, the gas spring is in a compressed state. In that situation, the mechanical securing device 15 which locks the elements 30,31 to one another prevents the gas spring 40 from pushing the upper element 31 upwards and rearwards along the rails 32a,32b. In an advantageous embodiment of the securing device 15 according to Figures 2 and 3, a running track 16 fastened to the lower element 30 (which is itself fastened to the vehicle) cooperates with a rear end section 50 of a locking device 17. The latter is supported for pivoting about a spindle 41 on the upper element 31 and incorporates on either side of the seat a locking part 44 and a yoke 43 which is fastened thereto by separate fastening devices 46 and which is entered by the rear end section 50. The yoke 43 consequently extends between the two sides of the upper element 31 , and the two locking parts 44 are each supported for pivoting about the spindle 41. The locking device 17 itself co-operates with a release device 18 which is mounted for pivoting about a spindle 45 on the upper element 31. Manual operation of the substantially vertical lever 23 which is readily accessible to the driver and situated beside the seat, level with the seat cushion, will make the release device 18, against the action of a spring 19, cause the locking parts 44 and the yoke 43 of the locking device 17 to pivot clockwise, in Figure 3, about the spindle 41. The forward toothed ends 21 of the locking parts will thus be raised from a co-operating securing position relative to the toothed rails 32a which are fastened along both sides of the lower element 30 (which is itself fastened to the vehicle). This raising takes place against the action of a spring 24 whose ends are fastened to the respective locking part 44 and to the upper element 31. The running track 16 is with advantage placed alongside a longitudinal symmetry plane of the elements 30,31, and the yoke 43 has a more or less symmetrical extent as seen in a horizontal plane, resulting in substantially even distribution of the forces acting upon the rails. Pivoting the lever 23 about its spindle 45 causes the yoke 43 to be acted upon so that the locking parts 44 can be raised from their securing positions. When this has taken place, the spring 40 urges the upper element 31 rearwards along the plane 33. In cases where the plane 33 exhibits a definitely downward forward slope, this takes place against the action of the person sitting in the seat who, by slightly reducing his weight on the seat, makes the movement possible. The force exerted by the spring 40 has a component in the vertical direction which, depending on the slope of the plane 33, constitutes a predetermined proportion of a statistical mean of the weight of adult persons. The yoke 43 and its rear end section 50 which is provided with a roller and is intended to cooperate with the running track 16 are urged by the action exerted by the respective springs 40 of the locking parts 44 to bear on the running track 16 during the movement of the element 31 along the rails 32a,32b to a rear end position. This movement is limited by the maximum length of the gas spring 40 (see Figure 2) and/or by a purely mechanical stop, e.g. in the form of a considerable downward bend (depicted in Figures 2 and 3) of the running track 16. In this case, no seat position locking takes place at the upper end position, as the seat will slide down along the plane if the weight load exceeds the aforesaid vertical force component. Only when the rear end device 50 of the yoke leaves the upwardly rounded forward end of the running track 16 can the locking parts 44 assume a securing position relative to the lower element 30. The invention thus makes possible a predetermined driving position of the seat which can be finely adjusted in a conventional manner by setting the seat in the longitudinal direction by means of the rails which are fastened in the horizontal plane 34 to the top of the upper element 31. The seat can also be set in the vertical direction by means of a height setting device in the seat frame 35 in a manner known per se and not described here. The lever 23 is so placed as to be operable not only by a person sitting in the seat but also by another person who is in the cab or interior of the vehicle and can accordingly easily act upon the lever, inter alia by means of his foot, to move the seat to either end position. In a truck cab the seat can thus be moved to the forward position to provide extra clear space in the cab, e.g. to make overnighting in it more comfortable. The lever 23 may also be provided with a securing arrangement to prevent inadvertent manual operation. The securing arrangement may consist of a recess 45 from which the lever 23 has to be raised by a tilting movement transverse to the forward direction of the seat, against the action of a spring (not depicted here), before the lever can be operated. The securing device may of course take various different forms, e.g. with the possibility of a securing position in a rear (resting) position of the seat. In driving seat applications, however, it is advantageous for it to be designed to only secure the lower (driving) position, while the resting position has no securing arrangement. This eliminates the risk of the driver being able to set the vehicle in motion while the seat is in the resting position. It has instead the advantageous effect that the driver glides in a controlled manner down the sloping plane as soon as the seat is sat on in its resting position, whereupon the preset driving position is automatically assumed. It is of course also possible to choose from among a number of alternative end positions below the end of the running track, which can be achieved by the release device being operated while at the same time the driver suitably increases the weight force on the seat in order to overcome said vertical force component. This will usually be unnecessary, however, since the seat still has the possibility of longitudinal setting by movement along the rails in the horizontal plane which are fastened to the top of the upper element 31.

Claims: Patent claims 1. Arrangement for a vehicle seat which is arranged to be movable, relative to a device (30) fastened to the vehicle, between at least forward and rear end positions, whereby a locking device (17) is arranged, between the vehicle seat and the device fastened to the vehicle, in order to lock the position of the vehicle seat relative to the device fastened to the vehicle, and a release device (18) is arranged to neutralise the locking action of the locking device, characterised in that a control device (16) cooperates with the locking device during the relocating movement between forward and rear positions of the seat so that the locking device (17) thereby becomes free from at least one locking position between the vehicle seat and the device (30) fastened to the vehicle, and that the rear end position consists of a resting position not intended for use when the vehicle is in motion. 2. Arrangement according to patent claim 1, characterised in that the rearward relocating movement is assisted by a first force. 3. Arrangement according to patent claim 2, characterised in that the forward relocating movement is opposed by a second force. 4. Arrangement according to patent claim 3, characterised in that the locking device incorporates a rail mechanism (32a,32b) which is known per se for vehicle seats and provided with a number of locking positions and along which the seat is mounted for movement, which rail mechanism is situated in a plane (33) which slopes downwards in the forward direction of the vehicle so that a corresponding seat relocating movement in the longitudinal direction of the vehicle can take place. 5. Arrangement according to any one of patent claims 1-4, characterised in that the cooperation of the control device (16) with the locking device (17) causes in at least one forward position the locking action with the device (30) fastened to the vehicle, which position is, during vehicle operation, a normal position of use of the seat relative to the device fastened to the vehicle. 6. Arrangement according to any one of patent claims 1-5, characterised in that during movement of the seat to a rear (resting) position the control device (16) controls the locking device (17) so that locking of the seat relative to the device (30) fastened to the vehicle does not take place at said rear position. 7. Arrangement according to any one of patent claims 1-6, characterised in that the control device (16) consists of a running track which extends in the longitudinal direction of the vehicle and is fastened to the device (30) which is itself fastened to the vehicle, which running track at least during movement of the seat cooperates with an end portion (50) of the locking device (17) so that said cooperation results in a securing part (44,21) of the locking device becoming free from a multiplicity of locking positions between the seat and the device fastened to the vehicle. 8. Arrangement according to patent claim 7, characterised in that the locking device (17) is mounted on the seat for pivoting about a spindle (41) in the transverse direction of the vehicle, and the end portion (50) co-operating with the running track is situated behind, while said securing part (21) is situated in front of said spindle. 9. Arrangement according to patent claim 7 or 8, characterised in that the co-operation of the end portion (50) of the locking device with the running track (16) takes place under the action of a force which pushes the end portion upwards towards the running track. 10. Arrangement according to patent claim 7, 8 or 9, characterised in that the forward end portion of the running track (16) is designed so that the securing part (44,21) of the locking device is allowed to assume a locking position relative to the device (30) fastened to the vehicle, while the rear end portion of the running track not only prevents the securing part assuming such a locking position but also constitutes a stop for the rearward movement of the locking device and hence of the seat. 11. Arrangement according to any one of patent claims 1-10, characterised in that the release device is supported pivotingly on the seat and is provided with a substantially vertical lever (23) whose upper end is situated on the side of the seat which faces the centre of the vehicle and is substantially level with the seat cushion. 12. Arrangement according to any of patent claims 1-11, characterised in that the seat is supported by a subframe with an upper element (31) which has its underside co-operating with the device (30) which is fastened to the vehicle, and its top co-operating with a frame (35) which supports the seat and back support elements, which co-operation on both the underside and the top makes it possible for the co-operating parts to move relative to one another in the longitudinal direction of the vehicle. 13. Arrangement according to any one of the foregoing claims, characterised in that the seat is also settable in height, which height setting takes place in a substantially vertical direction. 14. Subframe for a vehicle seat which consists of a supporting frame (30) which is triangular in the vertical plane and which on one side, which is a cathetus, is fastenable either to the vehicle floor (4) or to the seat (2), and on the hypotenuse side bears a first rail device (32a) which forms a sloping plane (33), and of a second supporting frame (31) which on the hypotenuse side bears a second rail device (32b) for co-operation with the first rail device (32a), and on a cathetus side bears a third rail device for co-operation with a fourth rail device either on the vehicle floor (4) or on the seat (2) in order to bring about longitudinal relocating movement along the horizontal plane (34), characterised in that the supporting frames (30,31) are essentially alike and that one supporting frame (31) exhibits a locking device (17) which can lock the seat in a forward position and which co-operates with a control device (16) during upward movement of the supporting frame (31) along the rails (32a,32b) to an upper resting position not intended for use when the vehicle is in motion, which co-operation results in the locking device (17) becoming free from at least one locking position. 15. Subframe according to patent claim 14, characterised in that a spring device (40) acts upon the supporting frames (30,31) in order to push them along the sloping plane (33).

Inventors: JONSSON STEFAN, LESTANDER STEN-ERIK, SJOESTROEM STAFFAN, JONSSON, STEFAN, LESTANDER, STEN-ERIK, SJOESTROEM, STAFFAN
Applicants: JONSSON STEFAN, LESTANDER STEN ERIK, SCANIA CV ABP, SJOESTROEM STAFFAN, JONSSON, STEFAN, LESTANDER, STEN-ERIK, SCANIA CV AKTIEBOLAG (PUBL), SJOESTROEM, STAFFAN
Application year: 1998
Main classification: B60N2
IPC codes: B60N2