APPARATUS FOR AUTOMATIC HORIZONTAL ADJUSTMENT OF A SEAT

Abstract: An apparatus for automatic horizontal adjustment of a seat of a motor vehicle or a vessel comprises a base in form of a base plate (11), drive means (30, 32) fixed at the base plate (11), and a seat element (5) displaceably connected with the base plate (11) and arranged to be positionally influenced by the drive means (30, 32). The displaceable connection is obtained by lateral annular segment beads of the seat element (5), running in facing grooves of two lateral supports (12, 13) fixed at the base plate (11). For horizontal adjustment the seat element (5) is rotated around an imaginary axis extending above the seat element (5). Horizontal adjustment is controlled by a detection means arranged at the underside of the seat element (5) and by a means for control of the drive means (30, 32) and coupled with the detection means. Also disclosed is a combination of two of said apparatus for horizontal adjustment by independent rotation of a seat around two axes perpendicular to each other in vertical projection.

Description: "Apparatus for automatic horizontal adjustment of a seat" The present invention relates to an apparatus for automatic horizontal adjustment of a seat, in particular a seat of a motor vehicle or a vessel, said apparatus comprising a base, a drive means, a seat element, said seat element being movably connected with the base and said drive means being designed to affect the position of the seat element, said seat element being arranged for restricted rotation about an axis of rotation parallel with the base, at least one detection means for detection of the position of the seat element in respect of a horizontal plane, and control means for control of the drive means, said control means being coupled with the detection means. Known devices for automatic horizontal adjustment of a seat are used for reasons of comfort and ergonomics for compensating inclination at low speed vehicles, such as, for example, tractors or caterpillars. Such a known device, for instance, is disclosed in the Norwegian laid-open patent application No. 169 056. This and other known devices for horizontal adjustment share the feature of the seat base being articulately mounted in vertical support elements of the base. Thereby the rotational axis of the seat element thus is positioned between the base and the seat plate. The position of the rotational axis in respect of the seat plate makes known devices to be in a position of instable equilibrium, both in the starting position with the vehicle/base on flat ground as well as in a position in which the vehicle is tilted and the device has compensated for this tilt by a corresponding rotation of the seat element. The purpose with the drive means to also keep the seat plate in its adjusted position in addition to compensating for inclination is a result of this instability. This necessitates dimensioning of the drive means for the additional objective which, per se, does not contribute to the result intended to be achieved. An objective with the present invention is to disclose an apparatus for automatic horizontal adjustment of a seat of a motor vehicle or a vessel that does not have this disadvantage. According to the invention the objective is met by an apparatus for automatic horizontal adjustment the seat element of which is arranged between the rotational axis and the base. For affecting the position of the seat element by the drive means it is preferred to arrange at least one guide at a constant distance from the rotational axis, said guide being arranged on the side of the seat element facing the base or the side of the base facing the seat element. It is preferred for the guide to have the form of an ellipse segment in its longitudinal extension and to have a rectangular profile in transverse section. It is furthermore preferred for the drive means to comprise at least one force transfer means affecting said guide. In addition to said force transfer means the drive means preferably comprises an electric motor, a means for reversal of direction of motor rotation and a rotational screw means coupled with the motor axis for cooperation with said force transfer means, said force transfer means surrounding said rotational screw means. In accordance with a preferred embodiment of the invention the force transfer means comprises wheels or rolls abutable with the lateral walls of the guide, the axes of said wheels or rolls being perpendicular to the base or the seat element. If several guides are used, a feature which is also preferred, each of these guides is provided with at least one wheel abutable with at least one of the lateral walls of the respective guide, the wheel axes being preferably arranged in respect to each other at an angle greater than zero. According to an advantageous aspect of the invention the force transfer means is arranged for reciprocating movement parallel to the base or the seat element and tangential in respect of the cylinder defined by the edges of the guide. According to an advantageous aspect of the invention the displaceable connection of the seat element with the base is obtained by cooperating bearing elements fixed directly or indirectly at the base and at the seat element, respectively, at least one of said bearing elements having a bearing surface formed like a cylinder segment, the center of which is defined by the rotational axis, and wherein the bearing element cooperating with the bearing surface formed like a cylinder segment comprises glide, roller or ball means. As already mentioned it is advantageous for the apparatus according to the invention to comprise two or more guides. Each guide is provided with at least one wheel or roller abutable against at least one lateral wall of the respective guide, the axis of at least one of the wheels and/or rollers being arranged inclined in respect of the base. It is also of advantage for the wheels or rollers to have the shape of double cones or to have a rounded profile abutable against the lateral walls of the guide, the profile of said lateral walls being adapted to the profile of the wheels or rollers. Another preferred embodiment of the invention providing multilateral positional compensation comprises a combination of two of the above disclosed apparatus according to the invention for positional compensation sideways or forward/backward, wherein the seat element of the one apparatus for positional compensation forms the base for the other apparatus for positional compensation, and wherein the rotational axes of both apparatus are perpendicular to each other in a vertical projection from above on a horizontal plane. The combined apparatus comprises optionally one or several detection means for monitoring the inclination of the seat. In the following the invention will be explained in more detail by a preferred but not limiting embodiment of the invention schematically illustrated in a drawing, in which is shown by Fig. 1 a lateral perspective view from above of the apparatus for horizontal adjustment according to the invention, after removal of the seat element, Fig. 2 the same view as in Fig. 1, additionally having the anterior side support removed, Fig. 3 a seat element in top view, from below, Fig. 4 the seat element of Fig. 3, in lateral perspective view from above, and Fig. 5 the apparatus for horizontal adjustment, complete with the seat element of Fig. 4 mounted. The apparatus for horizontal adjustment shown in Figs. 1 - 5 comprises a base 1, a drive, a seat element or support 5 and a detection means 7. The base 1 is a rectangular shape-permanent steel plate 11; other materials, such as aluminum and plastic, are also conceivable. Vertical lateral supports 12, 13 are mounted at opposite sides of the plate 1 by screws (not shown) applied from beneath. The base plate 11 is intended for mounting by means of bolts (not shown) at a location in the vehicle where the driver's seat is normally being mounted. The inner walls of lateral supports 12, 13 are provided with glide grooves 16, 17 curved in form of circular segments; the grooves' 16, 17 profile is rectangular in transverse section. The glide grooves 16, 17 are arranged symmetrically, that is, they define the position of a virtual cylinder from the axis of which all points on the upper lateral walls 18, 19 and the lower lateral walls 20, 21, respectively, are equidistant. Between the lower glide grooves' points 20, 21 which are at closest distance to the base plate 11 and the base plate 11 one bore each is arranged in the lateral supports 12, 13, of which only that in support 13 is a through bore. Bore 12 is provided with a bushing for supporting the unthreaded end portion of a rotational screw 31 extending with its other end exteriorly of lateral support 13, the other end being rigidly connected with the output shaft of an electric motor 32 (not shown in detail) rigidly mounted at the outside of lateral support 13 and exteriorly of the space between base plate 11 and seat element 5. By polarity reversal the motor 32 can rotate the rotational screw 31 in optional direction of rotation. Since sideways compensation of inclination of a vehicle generally is the most desired one orientation of base plate 11 after its mounting on the vehicle is such that motor 32 will be positioned in front of or behind the seat. By using a compact motor with integrated worm gear the motor can be mounted at the front side of the seat without the protruding motor disturbing the user. Mounting at the front side provides better access for repair and potential arrangement of a manual adjustment means to be used in case of power failure. Between supports 12, 13 a force transfer element 30 is mounted on the rotational screw 31 and on cylindrical guide bars 34, 35. In this particular embodiment the force transfer element 30 has the form of a rectangular parallelepiped; other forms are, however, conceivable. The screw 31 passes through a threaded bore in the center of the vertical longitudinal sides; the threads in the bore have the same pitch as the threads of rotational screw 31 with which they cooperate. On either side of the threaded bore the force transfer element is provided with two non-threaded through bores having a diameter only slightly larger than the diameter of guide bars 34, 35 making them glide in the respective bore. Guide bars 34, 35 extend parallel with the rotational screw 31 between supports 12, 13 and have a length suitable for being kept fixed after mounting in non- through bores made in supports 12, 13. On the top side of force transfer element 30 two cam rolls 40, 41 are rotatably mounted on axes 42, 43 perpendicular in respect to the top side. Axes 42, 43 are firmly mounted in holes made in the top side of force transfer element 30 and arranged side-by-side, said holes being arranged unsymmetrically in respect of force transfer element 30 in a way that one cam roll is positioned somewhat closer to support wall 12 and the other cam roll 41 somewhat closer to support wall 13. The seat element 5 is made in massive light castings (it can, of course, also be made in a number of other materials, such as plastics) , and is here about square and flat at its top side 51 and convexly curved at its underside 52 facing base plate 11 in a mounted state, that is, like a segment of a cylinder. The width of seat element 5 as measured between its lateral faces 53 and 54 is slightly smaller than the distance between lateral supports 12, 13. The seat element 5 is provided with circularly curved sliding beads 55, 56 having the same rectangular profile as the circularly curved glide grooves 16, 17 of the lateral supports, the profile width of said glide beads 55, 56 being very slightly reduced in respect to the distance between walls 18 and 20, and 19 and 21, respectively. At its underside the seat element 5 has a guide 58 for receipt of cam rollers 40, 41, each of which abuts a parallel side wall 59, 60 of guide 58. The guide is drawn through the center of the underside of seat element 5 and extends therefrom obliquely in direction of side walls 59, 60 at an angle α of between about 10° to 45°, the extension being the same in both directions. The angle a is defined as the angle included between the vertical projections of the center line 65 of guide 58 and the axis of rotation 66, said projection being a projection on the plane defined by the top side 51 of seat element 5 in its parallel position in respect of the base plate 11. The section of the edges of lateral walls 59, 60 with the part of the underside of seat element 5 where guide 58 is arranged resembles an ellipse segment. On its top side the seat element 5 has threaded bores (not shown) for mounting the driver's seat. On its underside the driver's seat has a mounting plate (not shown) with wider extension than than the top surface of the seat support; the mounting plate is attached with screws fastened in said bores and is provided with a circumferential removable rubber bellows surrounding the apparatus for horizontal adjustment and protecting it against dust and dirt. The detection means 7 (not shown in detail) is attached in a recess to the underside 52 of seat element 5. The apparatus for horizontal adjustment shown in Fig. 1 is mounted in the following way. Support 12 is mounted on base plate 11. Guide bars 34, 35 are inserted into the bores arranged for them in support 12 and the force transfer means is slided on guide bars 34, 35. Thereafter the free ends of guide bars 34, 35 are inserted into the bores arranged for them in support 13 which is then mounted on the base plate. The rotational screw 31 is guided through the bore made in support 13 towards the threaded hole in the force transfer means 30 and is then screwed into that hole until the front end extends into the bore arranged in support 12 to receive the free end of rotational screw 31, said bore being provided with a fitting bushing. The motor shaft is coupled to the end of rotational screw 31 adjacent to the motor and the motor 32 is secured by screwing it to the outside of lateral support 13. Seat element 5 is inserted with its glide beads 55, 56 into glide guides 16, 17 of the lateral support until its top face 51 is in a horizontal position, in which position a mounting through hole 57 arranged in the center of seat element 5 is positioned above the hole (not shown) provided in the force transmission means 30 for mounting of cam roller 40 shaft 42, thus enabling mounting to take place. The other cam roller 41 is mounted after bringing mounting hole 57 in an overlapping position with the hole (also not shown) arranged to receive axis 43 of cam roller 41, the positioning being obtained by turning the rotational screw a few windings. The diameter of mounting hole 57 is the same as or slightly smaller than the width of guide 58. Thereafter the seat is mounted on the seat element and required electric circuit connections are made, comprising connection of the motor/control unit to a power source, such as, for example, the battery of the vehicle. Instead of mounting base plate 11 on the floor portion of the vehicle it can be mounted on a base attached to that floor portion, said base being rotatable by hand and lockable in any position. The mechanical function of the apparatus is easy to understand. Starting motor 32 sets rotational screw 31 in rotation and thereby displaces the force transfer means 30 in a directon from or towards motor 32, depending on direction of rotation. Thereby cam rollers 40, 41 affect the respective lateral wall 59, 60 of guide 58 and force the seat element's glide beads 55, 56 to glide in glide guides 16, 17, thereby slightly turning the seat plate around its rotational axis 66. The mechanical function is used for automatic horizontal adjustment by arranging a position monitoring means 7 on the underside of seat plate 5 or other suitable location, said monitoring means inducing a control circuit to provide the motor with control commands required for automatic positional control. Such means for positional detection and control circuits are referred to, i.a., in the aforementioned Norwegian patent application no. 169 056. On deviation of the seat element's 5 plane 51 from horizontal position a control signal is created which, depending on whether the deviation being negative or position, makes the motor rotate 32 and the rotational screw 31 to displace the force transfer means 30 by means of cam rollers 40, 41 in the direction effective for compensation of positional deviation. Also possible is a "reverse" solution of the problem of driving of seat element 5, mirroring the above described solution. In this "reverse" solution the motor and the force tranfer means are attached to seat element 5, preferably at its underside, and the guide is arranged at the top side of base 1. In such case base 1 is no longer flat but has a surface on its top side which, in principle, is complementary to the underside 52 of seat element 1, that is, concavely curved. By suitable measures the expert in the art will adapt the above described movable connection of the seat element 5 with the base 1 to the "reverse" solution. The latter has the advantage of additional saving of space but is technically somewhat more complicated.

Claims: C l a i m s 1. Apparatus for automatic horizontal adjustment of a seat, in particular a seat of a motor vehicle or a vessel, said apparatus comprising a base, a drive means, a seat element, said seat element being displaceably connected with the base and said drive means being designed to affect the position of the seat element, said seat element being arranged for restricted rotation about an axis of rotation parallel with the base, at least one detection means for detection of the position of the seat element in respect of the horizontal plane, and control means for control of the drive means, said control means being coupled with the detection means, c h a r a c t e r i z e d in that the seat element (5) is arranged between the rotational axis (66) and the base (l) . 2. The apparatus of claim 1, c h a r a c t e r i z e d in that, for affecting the the position of the seat element (5) by the drive means, at least one guide (58) is arranged at a constant distance from the rotational axis (66), said guide (58) being arranged on the side of the seat element (5) facing the base (1) or the side of the base (1) facing the seat element (5). 3. The apparatus of claim 2, c h a r a c t e r i z e d in that in its logitudinal extension the guide (58) has about the form of an ellipse segment. 4. The apparatus of claim 2 or 3, c h a r a c t e r i z e d in that the guide (58) has a rectangular profile in transverse section. 5. The apparatus of any of claims 2 to 4, c h a r a c t e r i z e d in that the drive means comprises at least one force transfer means (30) for affecting the guide (58). 6. The apparatus of claims 5, c h a r a c t e r i z e d in that the drive means, in addition to said force transfer means (30), comprises an electric motor (32), a means for reversal of direction of motor rotation and a rotational screw means (31) coupled with the motor axis for cooperation with said force transfer means (30), said force transfer means (30) surrounding said rotational screw means (31). 7. The apparatus of claim 5 or 6, c h a r a c t e r i z e d in that the force transfer means comprises wheels or rolls (40, 41), each roll or wheel being abutable with at least one of the lateral walls (59, 60) of the guide means (40, 41). 8. The apparatus of claims 7, c h a r a c t e r i z e d in that the axes (42, 43) of said wheels or rolls (40, 41) are perpendicular to the base (1) or the seat element. 9. The apparatus of any of claims 6 to 8, c h a r a c t e r i z e d in that the force transfer means (30) is arranged for reciprocating movement parallel to the base (1) or the seat element and tangential in respect of the cylinder defined by the edges of the guide (58). 10. The apparatus according to any of preceding claims, c h a r a c t e r i z e d in that the displaceable connection of the seat element (5) with the base (1) is obtained by cooperating bearing elements (16, 17; 55, 56) fixed directly or indirectly at the base (1) and at the seat element (5), respectively, at least one of said bearing elements having a bearing surface formed like a cylinder segment (18, 20; 19, 21), the center of which is defined by the rotational axis (66). 11. The apparatus according to claim 11, c h a r a c t e r i z e d in that the bearing element (16, 17) cooperating with the cylindrical bearing surface (18, 20; 19, 21) comprises glide, roller or ball means. 12. The apparatus according to any of claims 2 - 11, c h a r a c t e r i z e d in that it comprises two or more guides and for each guide at least one wheel or roller abutable against one of the lateral walls of said each guide, the axis of at least one of the wheels and/or rollers being arranged inclined in respect of the base (1). 13. The apparatus according to any of claims 2 - 11, c h a r a c t e r i z e d in that the wheels (40, 41) or rollers have the shape of double cones or have a rounded profile abutable against the lateral walls of the guide (58), the profile of said lateral walls being adapted to the profile of the wheels or rollers. 14. A combination of two apparatus according to any of preceding claims, cc h a r a c t e r i z e d in that the seat element (5) of one apparatus for positional compensation forms the base (1) for the other apparatus for positional compensation, the rotational axes (66) of both apparatus being arranged perpendicular to each other in a vertical projection from above on a horizontal plane, the combined apparatus optionally comprising one or several detection means (7) for monitoring the inclination of the seat.

Inventors: CARLGREN KLAS, CARLGREN, KLAS
Applicants: CARLGREN KLAS, CARLGREN, KLAS
Application year: 1993
Main classification: B60N2
IPC codes: B60N2