MXPA98003291A - Cardanic driver block for the vehic seat adjuster - Google Patents

Abstract

The present invention relates to a drive apparatus suitable for a mechanical seat adjuster which includes a rotating advancing screw disposed between a top guide movably mounted with respect to a stationary lower guide. An impeller block is installed rotatably in the lower guide for rotation about an axis that extends perpendicular to the lower guide. A first bore extending through the drive block to receive the feed screw carried in the upper guide. An interleaved piece is installed so that it can move in a second bore in the drive block, the second bore extends in the transverse direction to, and intersects the first bore. A third transverse, threaded hole formed in the insert is threadably coupled to the lead screw. The first perforation has a larger diameter than the diameter of the advancing screw to allow the pivoting movement of the insert and the advancing screw about an axis extending through the second perforation. The first perforation also has a larger diameter than the third perforation of the interleaved piece to allow lateral movement of the interleaved piece inside the driving block, while maintaining in communication a first perforation and the third perforation of the intercalary piece.

Description

- CARDANEOUS IMPULSOR BLOCK FOR THE VEHICLE SEAT ADJUSTER Field of the invention The present invention relates, in general, to the adjusters for the seat of vehicles.

Description of the technique Mechanical seat adjusters are a common option in many automotive vehicles and are often offered as standard equipment in high-priced vehicles. These mechanical seat adjusters are mainly used in the driver's seat and, occasionally, in the front passenger seat of the vehicle to provide selective horizontal and vertical movement of the seat, as well as movement to recline the seat backrest to accommodate the occupants of different size and height, as well as to provide a comfortable seating position to suit the preference of each occupant. for seat, as a matter of fact, they have a seat support structure that supports the lower part of the seat and sometimes the seat backrest of a vehicle seat. The seat support structure is installed in the first and second separate guide or track units, each formed in an upper guide which is connected to the seat support structure and which is slidably installed on a lower guide anchored to the floor vehicle. A drive mechanism usually includes an electric motor that bi-rotationally rotates a pair of drive shafts that extend outwardly from the motor to a gear unit or housing installed in each upper guide. In a distribution, each gearbox rotates a feed screw that extends longitudinally downward and that carries each upper guide. A drive block is fixedly installed to each lower guide and threadedly receives the feed screw to make reciprocal, horizontal movement of the upper guide and the support structure of the seat attached in relation to the lower guide which is fixed to the lower guide. vehicle with the selective energization of the driving motor and drive shafts. Similar drive mechanisms are provided for vertical adjustment (up and down) of the seat support structure and, in a seat adjuster having an adjustment mechanism, for reclining the seat, to adjust the angular position of the seat backrest. seat with respect to the bottom of the seat. The vertical drive mechanism may also include front and rear seat adjustment thrust mechanisms, spaced apart to selectively tilt the front and rear edges of the seat bottom, independent of each other, as well as to simultaneously raise and lower the seat of the complete vehicle or, in some applications, only the lower part of the seat or cushion. However, the rigid connection between the mechanisms of the gear unit, the secondary shaft of the drive motor, the drive shaft, the feed screw and the drive block, often give problems during the assembly and operation of the mechanical adjuster for the seat of the drive unit. A vehicle. It is inevitable in the manufacture and assembly of a mechanical mechanism, such as mechanical seat adjusters, that poor dimensional conditions, such as concentricity, TIR, and linear discordances of nominal design dimensions can and do occur. These dimensional conditions, without correction, can cause various problems during the operation of a mechanical seat adjuster, such as poor finger separation of the stop position, slow operation of the mechanical adjuster for seating in extreme temperatures, excessive wear of the adjuster components. mechanical seat, irregular operation of the seat mechanical adjuster and the emission of unpleasant sounds or noises during the operation of the seat mechanical adjuster. To solve these problems mechanical seat adjusters have been designed in which the drive block is rotatably installed in a hole in the lower guide for rotation about an axis extending in the longitudinal direction through the drive block and perpendicular to the bottom guide. This rotation of the drive block is achieved by loosely installing the drive block in the lower guide hole without additional fasteners or by using a fastener with an enlarged head. In this last structure, the cylindrical mounting collar or hub extends from the drive block through the hole in the lower guide and receives the fastener in a bore with internal thread. The mounting collar has a length that [sic] the thickness of the lower guide to provide a smaller amount of vertical play between the drive block and the lower guide, to provide a smaller amount of vertical play between the drive block and the lower guide in order to allow the rotation of the driving block in the hole of the lower guide. These two types of rotating drive blocks accommodate variations in the end-to-end alignment of the lead screw and the bottom guide. Other drive blocks or support blocks or carriers that are used in the mechanical seat adjuster for connecting the drive shaft to a lead screw and / or for connecting the lead screw to an articulated mechanism of the seat block recliner are also known. with freedom of movement around two mutually exclusive axes. In this structure, the drive block or support block is provided with a pair of outwardly extending legs, which travel through the slots in a support bracket to allow rotation of the drive or support block around an axis which extends through the legs. The side walls of the clamp, which carry the grooves, are also formed slightly wider than the drive or support block to provide a small amount of lateral translation of the drive or support block in the clamp. However, until now there is not a drive block with adjustable movement in their directions or mutually exclusive axes to accommodate all alignment positions of a lead screw relative to a lower guide of the seat adjuster of a vehicle. Thus, it would be desirable to provide a seat adjuster for a vehicle having a single drive block that allows the drive block to conform to all alignment positions of a lead screw relative to a bottom guide or other components of the seat adjuster. A vehicle. It would also be desirable to provide this drive block in a manner that does not require modification of other components of the seat adjuster. It would also be desirable to offer a single drive block that accommodates all alignment positions of the feed screw to allow slow speed and high rotation of the drive screw torque without objectionable noise.

SUMMARY OF THE INVENTION The present invention consists of a driving device that is used advantageously in the seat adjuster of a vehicle. The driving apparatus includes first and second members, the first member is movable relative to the second member. The first member carries a threaded shaft. Means are attached to the threaded shaft to impart rotation to the shaft. The second member carries a driving block. Means, coacting with the driving block, are provided to allow pivoting movement of the threaded shaft in relation to the driving block around two perpendicular axes, each of the axes arranged perpendicularly mutually exclusive to the axes of rotation of the threaded shaft. The coactive means preferably include the means, which carries the drive block and which are threadably coupled to the threaded shaft extending through the first orifice means in the drive block, to produce linear movement of the threaded shaft and the shaft. first member in relation to the drive block and the second member as the threaded shaft is rotated. This means is rotatable around an axis perpendicular to the axis of rotation of the threaded shaft. The coactive or cooperating means also include the means, which carries the driving block and which is formed in the second member, to install in substantially axial form and fixes the driving block to the second member and to allow rotation of the driving block around an axis longitudinal extending through the drive block substantially perpendicular to the second member. This means includes a hole that is formed in the second member. A shaped mounting collar __ "* £ * • '_ ^ - in eXbi'oque impeller is installed in the hole in the second member. The hole and the mounting collar each have a circular cross-section, with an orifice diameter larger than an outer diameter of the mounting collar. The fastening means, engageable with the driving block, is provided to install the driving block on the second member, the mounting collar of the driving block has a thickness greater than a thickness of the second member to allow movement of the driving block with respect to the second member, when the driving block engages the second member through the holding means. Preferably, the first hole or bore is formed in the drive block to receive the threaded shaft. In addition, a second perpendicular perforation is formed in the drive block and intersects with the first hole and receives, in a movable manner, an interleaved part. A third threaded hole is formed in the insert perpendicular to the first hole and is threadably coupled to the threaded shaft. The insert is rotatable about an axis perpendicular to the axis of rotation of the feed screw to allow angular repositioning of the feed screw with respect to the drive block and the second member about this axis. The first orifice is, in one embodiment, a first bore extending through the drive block and having an internal diameter greater than the external diameter of the threaded shaft to accommodate the angular repositioning of the threaded shaft. The diameter of the first perforation is also greater than the diameter of the third perforation to allow lateral movement of the piece in the first perforation while maintaining the first and third perforations in communication. Expanded end flanges are formed in the body or insert to keep the body or part interleaved in the drive block while allowing lateral movement. The driving apparatus is ideally suited for use in an adjuster unit for the seat of a vehicle, wherein the first and second members are the upper and lower guides of one of the seat adjuster guide units. The threaded shaft is in the form of a feed screw arranged between the upper and lower guides and is carried with the upper guide. The single drive block of the present invention accommodates any positional arrangement of the lead screw with respect to the lower guide and solves any of the dimensional problems, such as the concentricity, IRR and Henal discrepancies of the nominal dimensions of the components in the seat adjuster. This allows the advancing screw, despite its variable positional arrangement with respect to the lower guide, to be rotated at the desired lower speed with high torque without noise, interference or objectionable wear.

BRIEF DESCRIPTION OF THE DRAWINGS The various features, advantages and other uses of the present invention will become more apparent in connection with the following detailed description and drawings, in which: Figure 1 is a partial, perspective view of a guide unit of a seat adjuster of a vehicle employing a drive block constructed in accordance with the teachings of the present invention; Figure 2 is a cross-sectional view, generally taken along line 2-2 in Figure 1; Figure 3 is an exploded view in lateral elevation of the drive block and the insert; Figure 4 is a perspective view of the interleaved piece shown in Figure 3; Figure 5 is a side elevational view of the assembled assembly block and the insert; and Figure 6 is a perspective view of an alternative embodiment of a drive block in accordance with the present invention. ~ J_7l DESCRIPTION OF THE PREFERRED EMBODIMENTS Now, in relation to the drawings and figures 1-5, in particular, a cardanic drive block is shown which is advantageously used in a vehicle seat adjuster, and in particular, a mechanical adjuster of the seat of a vehicle. The drive block accompanies a rotary shaft or feed screw to a stationary component, such as the lower guide of the seat adjuster of a vehicle to effect the movement of another component, such as an upper guide, in relation to the stationary component. or the lower guide, with the rotation of the axis or advance screw. As the construction and operation of an adjuster for the vehicle seat and, more particularly, a mechanical adjuster for the seat of a vehicle, are well known, an illustration and detailed description of the structure and operation of a vehicle will not be provided herein. seat adjuster of a vehicle. A complete description of a mechanical adjuster for the seat of a vehicle can be found by referring to the Statute Patent. No. 5,456,439, the content of which is incorporated herein as _P-- ~ -ref rén = ia. However, a brief description of a conventional seat mechanic adjuster will be provided in general to more clearly understand and appreciate the features and advantages provided by the gimbal drive block of the present invention. As is conventional, a mechanical seat adjuster supports a conventional vehicle seat that includes a lower seat or cushion and a seat backrest. In the seat mechanical adjuster, an upper structure is provided for the seat support to support the lower part of the seat and the seat backrest on the upper guide. The structure of the upper support of the seat includes a pair of members of the structure or rails that extend in the longitudinal direction, separated. Clamps or mounting surfaces are installed on the front end and the rear end of the structure members to connect the bottom of the seat with the upper support structure of the seat. A pair of pivoting clamps of the seat backrest is installed on each of the members of the seat support structure and provide a pivotal connection with the seat backrest, not shown, to allow for selective tilt or pivot movement of the backrest of the seat with respect to the lower opening of the seat, as is normal in the so-called "reclining seats". ? J The various drive units are installed in the mechanical seat adjuster to provide selective movements of the mechanical seat adjuster along the different axes. For example, the front and rear vertical impeller motors, respectively, are installed in the mechanical seat adjuster and are connected to conventional lead screws and drive blocks or nuts to independently elevate the front and rear edges of the limbs. The structure of the seat support, respectively, and by this means, provide selective vertical adjustment of the front and rear edges of the vehicle seat. In addition, the driver motor of the recliner for the seat backrest drives a pair of rotary driving shafts, each of which is coupled to individual driving screws. Each feed screw is connected by a drive link with one of the seat back pivot clamps installed on opposite sides of the seat mechanical adjuster to provide selective pivoting adjustment of the seat backrest relative to the bottom of the seat. a vehicle seat mounted on the members of the seat support structure. The mechanical seat adjuster also includes a horizontal drive means formed of an electric motor that is fixedly attached to one of the upper guides of the seat mechanical adjuster by a suitable clamp. A pair of directionally rotating driving shafts extend outwardly from a unit or gearbox integrally connected to the secondary shaft of the driving motor to a rotary connection, with a rotary or advancing screw disposed in each of a pair of opposed guide units. Figure 1 represents a part of one of the two vehicle guiding units that is located in the conventional seat adjuster of a vehicle. The guide unit includes a lower guide 10 which is adjusted by suitable mounting brackets in a stationary position on the floor of the vehicle. The lower guide 10 includes a generally flat base 11 having a pair of straight side walls 12 on opposite sides thereof. The side walls 12 are smoothly curved in and terminate in the inner flanges extending downwards 14. As shown in Figure 1, the inner flanges 14 are spaced apart from the side walls 12 to define a slot between them extending in the longitudinal direction along the lower guide 10. The upper guide 16 can have any of a different configurations. Just as an example, the upper guide 16 is formed of a pair of vertically extending side walls 18, the lower ends of which curve outwards and upwards to form extreme flanges 20. The flanges 20 are located in the groove formed between the inner flange 14 and the side walls 12 of the lower guide 10. A low friction sliding member 21 is placed between the surfaces of the flanges 20, facing each other, of the upper guide 16 and the side walls 12 and the inner flanges 14 of the lower guide 10 to facilitate the easy sliding movement of the upper guide 16 in relation to the stationary fixed lower guide 10. As shown in Figure 2, an opening 22 is formed in the lower base 11 of the lower guide 10. An actuator block generally defined by the reference number 30 is installed in the opening 22 of the lower guide 10. As shown in Figs. 1, 2, 3 and 5 the drive block 30 in the form of a generally cubic body 32, the body 32 has a four-sided configuration, by way of example only. In an alternative mode, it separate 23 and 24 project upwards from a base 25. A first groove or opening 26 is formed between the legs 23 and 24 and receives a rotating shaft or feed screw therethrough. The openings 27 formed in each of the legs 23 and 24 are aligned to accommodate an advancing screw that receives an interleaved piece, as described below. A mounting collar 28 projects from the base 25 to install the drive block in the lower guide 10, as also described below. The body 32 can be formed of any suitable material, such as a high-strength metal, that is, a cold-rolled steel, with low carbon or aluminum content, as well as other materials such as plastic, ie nylon 6, 6 In the exemplary configuration shown in Figures 1, 2, 3 and 5, the body 32 of the drive block 30 has a generally square cross section formed with four side walls 34, 36, 38 and 40. The corners of the side walls 34, 36, 38 and 40 are bevelled as shown in Figure 1, by way of example only. An upper wall 42 is formed at one end of the side walls 34, 36, 38 and 40 and is separated from an - * = opposite bottom wall 44. A mounting collar 46 projects from the bottom wall 44 and has a total diameter smaller of the width of the body 32 between the two opposite side walls 34 and 36 or 38 and 40. The mounting collar 46 is dimensioned to fit within the opening 22 in the lower guide 10, as shown in Figure 2, for "rotatably" locate the drive block 30 in the lower guide 10 for rotation about an axis extending in the longitudinal direction through the body 30 and perpendicular to the lower guide 10 as shown by arrow 48 in the Figure 1. As shown in Figures 2 and 3, a perforation 50 extends through the mounting collar 46 and the lower part of the body 32. The perforation 50 'is threaded and receives a threaded fastening means 52, such as a screw with thread, as shown in Figures 1 and 2. The fastener 52 has a threaded body or shank 53 and an enlarged head 54. The head 54 has a diameter greater than the diameter of the opening 52 in the lower guide 10. In this manner, the head 54 of the fastener 52 will sit against the outer surface of the mounting collar 46 and the base 11 of the lower guide 10, as shown in Figure 2. This provides a small space between the lower wall 44 of the drive block 30 and the base 11 of the lower guide 10 to allow the driving block 30 to rotate in a bidirectional direction about a longitudinal axis in the direction of the arrow 48 shown in Figure 1, while still fixing in the substantially axial direction the driving block 30 in relationship with the lower guide 10.

A first rotary shaft or feed screw that receives the bore 56 is formed in the body 32 extending between the side walls 34 and 36. The bore 56 has an internal diameter greater than the maximum outer diameter of the rotary shaft or feed screw 58. This allows pivoting movement of the lead screw 58 in the direction of the arrow 60, as shown in Figure 2 and is described in greater detail below. The difference between the diameters of the bore 56 and the feed screw 58 is such that the feed screw 58 is capable of pivoting movement between about 3 ° to 6 ° about an axis extending transverse to the bore 56. A second perforation 62 is also formed in body 32 transverse to and intersecting with first perforation 56. The axes of perforations 56 and 62 intersect each other and form a common plane. The second perforation 62 extends through the body 32 between the side walls 38 and 40, as shown in Figures 1 and 3. The second perforation 62 has a larger diameter than the diameter of the first perforation 56. As can be seen in FIG. shows in Figure 1, and in greater detail in Figures 2-5, an insert 70 is installed rotatably in the bore 72 in the body 32 of the drive block 30. The insert 70 is in the form of a tubular body 72 formed of a portion tubular or sleeve 73 having a substantially circular cross section extending from a first end 74 to a second end 76 which is in the form of an end flange with enlarged diameter and has a larger diameter than the outer diameter of the tubular sleeve 73 of the body 72. The intercalde 70 is formed of any suitable material, such as a high strength steel or other metal. In an alternative mode, it is also possible to use a suitable high strength plastic, such as nylon 6, 6 to form the insert 70 for use with a metal or plastic body 32 of the drive block 30. The outer diameter of the tubular portion 73 of the body 72 of the insert 70 in the size to fit closely within the bore 62 in the body 32 to securely hold the insert 70 in the body 32 while also allowing rotational and transverse movement of the insert 70 within of the Generation 62, as described below. As shown in Figure 4, a plurality of shaved ribs or ribs 78 can optionally be formed on the tubular exterior of the body 72 extending between the first and second ends 74 and 76 when the tubular body 72 is formed of a plastic material. The shaved shoulders 78 may be provided in any number, such as four shaved shoulders 78 spaced 90 ° around the circumference of the tubular portion 73. The shaved shoulders 78 deform when the insert 70 is forcedly inserted into the bore. 62 for the secure connection of the insert 70 with the external surfaces of the perforation 62 in the body 32, while allowing rotation of the insert 70 around a longitudinal axis extending between the first and second ends 74 and 76 of this and / or lateral movement of the insert 70 in the perforation 62. As shown in FIG. 3, the first end 74 of the body 72 has a small recess forming a raised peripheral protrusion. After the body 72 is inserted into the bore 72 in the drive block 30, the body 72 is placed in a die and anvil with a rounded end is brought into forced engagement with the first bore 74 of the body 72. The anvil forces and deforms the projection, at the first end 74 radially outwardly to form an enlarged projection or flange 75, as shown in Figure 5. The length of the body 72 between the internal faces of the flange 75 at the first end 74 and the flange 76 at the second end 76 is greater than the length of the body 32 between the side walls 34 and 38 to allow a small amount of movement of the body 72 within the body 32 while maintaining the body 72 in the body 32 and prevents the advancing screw 58 comes into contact with the internal surfaces of the bore 56 in the body 32. A transverse bore 80 is formed in the tubular sleeve 73 of the tubular body 72 of the insert 70, as shown in FIG. as Figures 2-5. The perforation 70 is threaded to engage the threads on the rotary shaft or lead screw 58. In addition, the opposite ends of the perforation 80 widen outwardly from the internal diameter of the perforation 80 to form conical surfaces 82. The threaded hole 80 allows the lead screw 58 to rotate inside the insert 70. However, the insert 70 is coupled to the body 32 of the drive nut 30 to provide bidirectional linear movement of the lead screw relative to the guide 30 and guide lower 10 in the form The previously defined structure of the drive block provides multiple axes and / or directions of movement of the drive block 30 relative to the lower guide 10 and the feed screw 58, which allows the drive block 30 to accommodate different position arrangements of the rotary shaft or advancing screw 58 in relation to the lower guide 10. As already described, the rotary assembly of the driving block 30 in the opening 22 of the lower guide 10 allows the driving block 30 to rotate about a longitudinal axis extending between the upper wall 42 and the lower wall 44 of the drive block 30 in the direction of the arrow 48 shown in Figure 1 to accommodate any end-to-end lateral displacement between the longitudinal axis of the lead screw 58 and the lower guide 10 At the same time, the insert 70 is able to rotate within the bore 62 in the body 32 of the drive block 30 about a longitudinal axis that s extends between the first and second ends 74 and 76 thereof to accommodate any non-parallel position between the longitudinal axis of the advancing screw 58 and the lower guide 10 since the insert 70 can rotate within the body 32 of the driving block 30 in the direction of the arrow 60, as shown in Figure 2. Further, as shown more clearly in Fig. 5, since the diameter of the first bore 56 in the body 32 of the drive block is larger than the diameter of the bore. the perforation 80 of the insert 70, and further, since the length of the sleeve 73 between the internal faces of the end flanges 75 and 76 is greater than the width of the drive block 30, the insert 70 is CcfaS: lateral movement between the side walls _t 38 and 40 of the body 32 of the drive block 30 to accommodate any lateral displacement of the longitudinal axis of the feed screw 58 relative to the longitudinal axis of the drive block 30 and the lower guide 10. The axis of motion already described in the driving block present allows the drive block to accommodate any positional arrangement of the lead screw 58 relative to the lower guide 10. This overcomes any dimensional or tolerance problems encountered in the manufacture and assembly of a seat adjuster and allows the screw advance 58 turn at the desired low speed with high torque without noise, subject or wear objectionable.

Claims (27)

CLAIMS. £ •

1. A driving apparatus comprising: first and second members, the first movable member in relation to the second member; a threaded shaft carrying the first member; the means, coupled to the threaded shaft, to impart rotation to the shaft; a drive block carried with the second member; and the medium, coacting with the drive block and the threaded shaft, to allow pivoting movement of the threaded shaft in relation to the drive block around two perpendicular axes, each of the two axes arranged in mutually exclusive perpendicular to an axis of rotation of the threaded shaft.

2. The driving apparatus of claim 1, wherein the coactive means comprises: the medium, carried with the driving block and relationship with the driving block and the second member as the threaded shaft is rotated; and the threadedly coupled means, rotating about a first axis perpendicular to the axis of rotation of the threaded shaft. & 3.

The driving apparatus of claim 1, wherein the coactive means further comprises: the means, carried with the driving block and formed in the second member, for the substantially axial attachment of the driving block with the second member, to allow the rotation of the drive block about a longitudinal axis extending through the drive block substantially perpendicular to the second member.

The driving apparatus of claim 3, wherein the coactive means comprises: an apparatus formed in the second member; and a mounting collar formed in the drive block and mountable through the opening in the second member.

The driving apparatus of claim 4, wherein: external mounting collar.

6. The driving apparatus of claim 4, further comprising: the clamping means, connectable with the driving block for coupling the driving block to the second member.

7. The driving apparatus of claim 6, wherein: the mounting collar of the driving block has a thickness greater than the thickness of the second member to allow movement of the driving block with respect to the second member, when the drive block engages the second member through the fastener means.

8. The driving apparatus of claim 7 further comprises: a threaded bore extending in the direction of the shaft through the mounting collar of the drive block, the fastening means threadably connectable with the threaded bore.

The driving apparatus of claim 8, wherein the fastening means comprises: a threaded body; and an enlarged head formed at one end of the threaded body; s% r the enlarged head in engagement with the mounting collar on the drive block and the second member when the body is threaded into the threaded bore in the mounting collar to separate the drive block from the second member, so that the rotation of the drive block with respect to the second member around an arm that extends through the mounting collar and the drive block.

10. The driving apparatus of claim 1 further comprises: a first bore extending through the drive block and receiving the threaded shaft therethrough, the first bore having an internal diameter greater than a maximum external diameter of the threaded shaft .

The driving apparatus of claim 10, wherein the coactive means comprises: a body carried by the drive block in the transverse direction and intersecting the first bore in the drive block, the body being rotatable with respect to the drive block in the vicinity of an axis perpendicular to an axis through the first bore; And a second threaded bore formed in the body perpendicular to the first bore and coupling threaded shaft; perforation with a diameter greater than a diameter of the second perforation to allow lateral adjustment of the body disposed in the second perforation with respect to the driving block while keeping the first and second perforations in communication.

12. The driving apparatus of claim 1, wherein the coactive means comprises: the first opening means, formed in the drive block for receiving the threaded shaft therethrough; a body carried by the drive block in the transverse direction and intersecting the first half opening in the drive block, the body being rotatable with respect to the drive block about an axis perpendicular to an axis through the first half opening; and a second threaded bore formed in the body, perpendicular to the first half opening and threadably connecting the threaded shaft.

13. The driving apparatus of claim 12 further comprises: the third aperture means formed in the drive block, perpendicular to, and intersecting the first aperture means, the body installed in the third aperture means. The driving apparatus of claim 12, wherein: a body is formed of a plastic material; at least one deformable rim formed on the outside of the body, a maximum external diameter of the body and at least one deformable rim greater than the internal diameter of the third bore in the drive block, so that the at least one deformable rim is deformed as the body is installed in the third half opening to mount firmly, immobile, the body in the third half opening of the drive block. The driving apparatus of claim 12, wherein: inwardly extending conical surfaces are formed between the ends of the second bore and the external surfaces of the body. The driving apparatus of claim 12, wherein the body comprises: a tubular sleeve having first and second opposite ends; and an enlarged extreme flange formed at the second end, the enlarged end flange having a diameter greater than a diameter of a tubular portion of the tubular sleeve. The driving apparatus of claim 13, wherein the body comprises: a tubular sleeve having first and second opposing ends; an enlarged end flange formed at the second end, the enlarged end flange having a diameter greater than a diameter of a portion of the tubular sleeve; an enlarged extreme flange is formed in the first _ * - extrémd tubular sleeve; the diameters of both end flanges in the first and second end of the tubular sleeve being greater than a diameter of the third half opening to retain the body in the drive block. The driving apparatus of claim 17, wherein: the length of the tubular sleeve between the end flanges at the first and second ends of the body is greater than a total length of the driving block along the third opening means. The driving apparatus of claim 1, wherein the first and second members comprise: lower and upper guides of a vehicle seat adjuster guide unit; the threaded shaft interposed between the lower and upper guides; the drive block mounted on the lower guide; and - _t-J ~ the means for bringing the threaded shaft in the upper guide for the co-extensive linear movement of the upper guide and the threaded shaft with the rotation of the threaded shaft through the drive shaft mounted on the lower guide. The driving apparatus of claim 1, wherein the coactive means comprises: the medium, carried in the drive block and threadably coupling the threaded shaft, to cause linear movement of the threaded shaft and the first member in relation to the drive shaft and the second member as the threaded shaft is rotated; means for producing linear movement rotating around a first axis perpendicular to a rotation axis of the threaded shaft; and the means, carried in the drive block and formed in the second member, for substantially axial fixed installation of the drive block to the second member and to allow rotation of the drive block about a longitudinal axis extending between opposite ends of the block. driving. The driving apparatus of claim 20, wherein the fixedly mounted means comprises: an opening formed in the second member, a mounting collar formed in the drive block and mountable through the opening of the second member; the opening of the second member and the mounting collar each having a circular cross-section, with a diameter of the opening greater than an outer diameter of the mounting collar; holding means, engageable with the driving block, for connecting the driving block with the second member; a threaded bore extending in the axial direction through the mounting collar of the drive block, the fastening means threadably engageable with the threaded bore; and the mounting collar in the drive block has a thickness greater than a thickness of the second member to allow movement of the drive block with respect to the second member when the drive block engages the second member through the securing means. The driving apparatus of claim 20, wherein the coactive means comprises: a first bore extending through the drive block having an internal diameter greater than a maximum external diameter of the threaded shaft; a body carried by the drive block in the transverse direction and intersecting the first bore of the drive block, the body being rotatable with respect to the drive block about an axis perpendicular to an axis of the first bore; and a second threaded bore formed in the body, arranged perpendicular to the first bore and threadably engaged with the threaded shaft. 23. The driving apparatus of claim 22, wherein the coactive means further comprises: a third bore formed in the drive block, perpendicular to, and intersecting the first bore, the body rotatably mounted in the third bore. 24. A mechanical seat adjuster consisting of: a lower guide; a top guide installed so that it can move with respect to the lower guide; a threaded lead screw; the driving means coupled to the feed screw for the rotation of the feed screw; and the coercive means, coacting with the driving block to allow pivoting movement of the threaded shaft in relation to the driving block around two perpendicular axes, each of the two axes arranged mutually exclusively perpendicular to an axis of rotation of the axle threaded The driving apparatus of claim 24, wherein the coactive means comprises: the medium, carried in the drive block and threadably engaged to the threaded shaft, to produce linear movement of the threaded shaft and upper guide relative to the drive block and the lower guide as the threaded shaft is rotated; means for producing linear movement rotatable about a first axis perpendicular to an axis of rotation of the threaded shaft; and the means, carried in the drive block and formed in the lower guide, for the substantially axial fixed assembly of the drive block to the lower guide and to allow rotation of the drive block about a longitudinal axis extending between opposite ends of the drive block. drive block. 26. The driving apparatus of claim 25, wherein the fixed mounting means comprises: an opening formed in the lower guide, a mounting collar formed in the drive block and mountable through the opening in the lower guide; the opening of the lower guide and the mounting collar each with a circular cross section, with an opening diameter being greater than an outer diameter of the mounting collar; holding means, engageable with the driving block for coupling the driving block to the lower guide; a threaded bore extending in the axial direction through the mounting collar of the drive block, the fastening means threadably engageable with the threaded bore; and the mounting collar in the drive block having a thickness greater than a thickness of the lower member to allow movement of the driving block with respect to the lower member when the drive block engages the lower member through the fastening means. The driving apparatus of claim 25, wherein the coactive means comprises: a first bore extending through the drive block and having an internal diameter greater than a maximum external diameter of the threaded shaft; a body carried by the drive block in the transverse direction to, and interacting with, the first bore in the drive block, the body being rotatable with respect to the drive block about an axis perpendicular to an axis of the first bore; and a second threaded bore formed in the body, arranged perpendicular to the first bore and threadably engaged with the threaded shaft. The driving apparatus of claim 27, wherein the coactive means further comprises: a third bore formed in the drive block, perpendicular to and intersecting the first bore, the bore rotatably mounted in the third bore. SUMMARY OF THE INVENTION The present invention relates to a driving apparatus suitable for a mechanical seat adjuster that includes a rotating advancing screw disposed between an upper guide movably mounted with respect to a stationary lower guide. An impeller block is installed rotatably in the lower guide for rotation about an axis that extends perpendicular to the lower guide. A first bore extending through the drive block to receive the feed screw carried in the upper guide. An interleaved piece is installed so that it can move in a second bore in the drive block, the second bore extends in the transverse direction to, and intersects the first bore. A third transverse, threaded hole formed in the insert is threadably coupled to the lead screw. The first perforation has a larger diameter than the diameter of the advancing screw to allow the pivoting movement of the insert and the advancing screw about an axis extending through the second perforation. The first perforation also has a larger diameter than the third perforation of the interleaved piece to allow lateral movement of the interleaved piece inside the driving block, while maintaining in communication a first perforation and the third perforation of the interleaved piece.