DE9408850U1 - Linear motion control - Google Patents

Description

Honor

The invention relates to a linear motion guide with a guide rail and a carriage supported on the guide rail via rolling or roller elements, wherein the guide rail is provided with at least one through-opening, which can be closed by a possibly metallic cover cap, for a fastening element for attaching the guide rail to a carrier, wherein the through-opening opens into a cover surface of the guide rail facing away from the carrier and is arranged in the movement area of the carriage.

Such linear motion guides are used in a variety of ways, especially in machine tool construction. The guide rail is attached to a machine bed or similar using fastening elements, which in most cases are made up of fastening screws with screw heads countersunk inside the guide rail, which rest against the corresponding ring shoulders of the stepped through holes. After assembly, the through holes are usually covered by cover caps that are flush with the cover surface of the guide rail. This prevents dirt, dust or workpiece chips or similar that have accumulated in the through holes above the screw heads from getting into the interior of the slide when it travels over the through hole. Such dirt and dust particles could get into the tracks of the balls or rolling elements.

which the slide supports itself on the guide rail, which would lead to increased wear and, in some cases, even to blockage. Irrespective of this, an uncovered through-opening would mean that a lip seal of the slide, which runs along the cover surface of the guide rail, could be damaged by the usually quite sharp-edged mouth edge of the through-opening in the cover surface.

Plastic cover caps are well known. In order to be able to easily hammer in the relatively easily damaged plastic cap, the mouth edge is provided with a bevel (chamfer). After the cap has been hammered into the through-opening using, for example, a hammer and a flat intermediate plate, a small annular groove remains between the chamfer and the cap. Dirt can build up in the annular groove; the lip seal can be damaged by constantly rubbing over the annular groove. A general disadvantage of plastic cover caps is their relatively low mechanical strength. For example, guide rails are sometimes driven over by forklifts; plastic cover caps cannot withstand the forces that occur, or are pushed further into the through-opening, so that they no longer sit flush with the cover surface.

In known metal closure caps, a collar is provided on the peripheral surface of the cover cap, which after the cover cap has been pressed into the through-opening, forms a press fit with the through-opening

This press fit is often not sufficient to keep the cover cap in the flush position in the through hole even when exposed to large external forces. The known cover cap can also be pressed or hammered in slightly crooked. Cover caps that still protrude slightly beyond the cover surface after being hammered in can be leveled by grinding or similar, but this means an additional work step.

The invention is based on the object of providing a cover cap for closing the through openings of guide rails, which is easy to install without rework and reliably covers the through opening flush.

This task is solved in that the cover cap has a head plate adapted to the outline of the through-opening and a spreading foot which rests against an essentially cylindrical peripheral surface section of the through-opening under essentially radial pre-stress. According to the invention, the covering function and the fixing function of the cover cap within the through-opening are therefore fulfilled by different components of the cover cap, namely the former function by the head plate and the latter function by the spreading foot. The head plate can therefore be largely adapted to the outline of the through-opening so that a noticeable annular groove is reliably avoided. The spreading foot, which is solely responsible for the fixing, can easily be designed in such a way that the radial pre-stress ensures a sufficiently strong press fit within the through-opening that can also withstand high loads. Since the spreading foot is not attached to a radial step surface,

but rests on the essentially cylindrical peripheral surface section under the desired radial preload, the expanding foot can, regardless of the dimensional tolerances, be pushed into the exact axial position when the cover cap is driven in, in which the top of the head plate is flush with the cover surface. Since the axial compression of the expanding foot when driven in is comparatively low, the expanding foot then only springs back slightly, so that in general there is no need to level the cover cap and the cover surface of the guide rail.

In order not to damage the guide rail when assembling and, if necessary, disassembling the cover cap, it is recommended that the cover cap is made of a slightly less hard material than the guide rail.

In order to adapt the head plate of the cover plate to the cylindrical through-opening as closely as possible, the peripheral surface of the head plate can be designed to be essentially cylindrical.

However, the peripheral surface of the head plate can also be designed to be essentially conical towards the spreading foot. This makes assembly somewhat easier, as at the end of the hammering-in process, the head plate can easily penetrate into the through-opening even if the cover cap is slightly slanted. Nevertheless, after hammering in, the head plate is flush with the cover surface and free of ring grooves, whereby a slight press fit can also be provided between the through-opening and the head plate in the area of the peripheral edge of the head plate on its top side.

In a further development of the invention, it is proposed that the diameter of a first section of the through-opening, which accommodates the head plate, is larger than the diameter of a second section of the through-opening, which accommodates the expanding foot. This measure makes assembly easier, since increased impact resistance only occurs when the cover cap is already partially inserted into the through-opening, namely when the expanding foot reaches the second section with a reduced diameter. Damage to the mouth edge of the through-opening in the cover surface by the expanding foot is also ruled out from the outset due to the comparatively larger diameter of the first section. The diameter of the first section can, under certain circumstances, even exceed the corresponding expanding foot diameter. The diameter of the second section, which is smaller than the spreader foot diameter, is set in such a way that the radial preload resulting from the difference in diameter creates a press fit between the spreader foot and the through-opening, the axial holding force of which is greater than the axial forces acting on the cover cap during operation (in particular when driving over the guide rail).

It is also proposed that the first and second sections are each cylindrical, and that a connecting section between the first and second sections is essentially conical. This facilitates the transition of the spreading foot from the first section to the second section while the through hole is easy to produce. The cover cap can also be used for

If the diameter of the second section is too small, it can be quickly hammered or pressed in.

This transition can be facilitated in addition to or independently of the conical design of the connecting section just described by providing the spreader foot on its outer circumference with a substantially conical bevel that tapers towards the end of the spreader foot. This conical bevel also ensures that the spreader foot can be moved into the through opening without damaging the spreader foot and/or through opening, even with a large radial preload, until the top of the cover cap is flush with the cover surface.

According to the invention, it is proposed that the spreading foot is formed by an annular wall protruding from the head plate. It is preferably provided that the annular wall expands essentially conically in the direction away from the head plate. This annular wall ensures the desired high radial preload force while the cover cap is easy to manufacture, in particular as a turned part.

Depending on the desired magnitude of the radial preload force, the ring wall can be continuous in the circumferential direction or slotted.

It is further proposed that the spreader foot be provided with at least one hook projection protruding radially outwards in the area of its end remote from the head plate. In this way, the press fit can be precisely localised and thus predictably concentrated on the at least one hook projection.

When forming the cover cap with the ring wall, the hook projection is preferably formed by a peripheral projection of the ring wall, which can also be referred to as a ring serration. By appropriately designing the peripheral projection with a bevel only at the end of the spreading foot, the hook projection or the peripheral projection can be designed like a barb to make it more difficult to remove the cover cap.

It is also proposed that the axial length of the expanding foot is greater, preferably slightly greater, than the axial length of the first section of the through-opening. In this way, the head plate is still outside the through-opening when the expanding foot is just resting on the step formed between the first and second reduced-diameter sections or on the conical connecting section. Since the step or the conical connecting section runs exactly symmetrically to the longitudinal axis of the through-opening, this automatically results in the cover plate being aligned coaxially to the said longitudinal axis of the through-opening, which runs perpendicular to the cover surface. If the cover cap is then subsequently driven or pressed further into the receiving opening, it will be easily fitted into the through-opening due to the precise orientation of the head plate.

In a first embodiment of the invention, the axial length of the first section is greater than the thickness of the head plate. This prevents a momentary axial compression of the head plate when it hits a step or the conical connecting section at the end of the first section and thus also a slight

Springback after impacting or pressing in is excluded. Such springback could require rework if the highest demands are placed on the planarity of the cover surface including the top of the cover cap.

In those applications where the cover cap has to be able to withstand extremely high loads, it can alternatively be provided that the axial length of the first section is equal to or slightly smaller than the thickness of the head plate. At the end of the impacting or pressing process, the peripheral edge of the head plate facing away from the top of the cover cap digs into the conical ring bevel formed by the connecting section. Under certain circumstances, however, the surface of the guide rail must be slightly leveled after the pressing process due to the elastic springback of the head plate, e.g. using a carborundum stone.

However, when using the cover cap described above, the problem arises during the actual assembly and alignment of the guide rail on the respective base, i.e. before the cover cap is hammered in, that the guide carriage already on the rail cannot be moved freely for testing purposes without damaging the lip seal of the sealing plates arranged on both front sides of the carriage when driving over the sharp-edged mouth of the respective through opening. As mentioned, the mouths of the through opening are so sharp-edged in order to avoid a corresponding annular groove between the edge of the cap and the edge of the through opening after the respective cover cap is hammered in.

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In order to avoid damage to the lip seals during assembly of the guide rail and before fitting the cover caps, it is proposed that the carriage provided with at least one lip seal running along the cover surface of the guide rail be provided with a mounting clamp for lifting the lip seal in the area of the mouth of the at least one through-opening. This solution to the problem is independent of the shape of the cover cap used, although it is preferably used in conjunction with the cover cap described above due to the particularly sharp mouth edge.

For quick attachment and removal of the mounting bracket after the cover caps have been fitted, it is suggested that the mounting bracket can be attached to the front of the slide.

Cost-effective manufacture of the mounting clamp while at the same time ensuring a reliable hold on the slide is ensured by the fact that the mounting clamp is essentially U-shaped with a central section for arrangement on a slide front wall and two side legs that are spring-loaded towards each other for spring-loaded contact with the top of the slide or the bottom of the slide between the slide and the guide rail.

The mounting bracket could be made of plastic, for example. However, a mounting bracket made of essentially U-shaped spring steel is particularly preferred, since a corresponding spring steel band requires a relatively low material thickness of less than 0.2 mm in particular while providing sufficient spring force. The lip seal is therefore

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The mounting clamp is only slightly deformed when the mounting clamp is attached, so that damage can be ruled out. The mounting clamp can also be used when there is a very small clearance between the top surface of the guide rail and the underside of the slide.

In order to ensure a controlled shape of the attached mounting bracket even with this low material thickness, it is suggested that the middle section of the U-shape of the spring sheet metal part is provided with a stiffening plate. The stiffening plate prevents the middle section from curving, so that the effective length of the middle section can correspond exactly to the corresponding height of the front face of the slide and thus the side legs can run exactly at right angles to this for flat contact with the corresponding slide surfaces. This reliably prevents the lower side leg of the mounting bracket from grinding on the guide rail; as well as this leg getting caught on one of the through openings with the possible consequence of the mounting bracket being accidentally released from the slide.

A protruding element, such as a grease nipple, is often provided on one of the two front sides of the slide. In order to be able to uncover the mounting bracket without hindrance, it is suggested that the mounting bracket be provided with a receiving opening for a grease nipple on the front side of the slide.

This grease nipple can be provided with a grease nipple head that protrudes at an angle. In this case, in order to avoid having to laboriously insert the grease nipple into the

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closed receiving opening, it is proposed that the mounting bracket be provided with a slot to form the receiving opening, which opens out at one of the two side leg ends of the U-shaped mounting bracket.

In order to ensure sufficient mechanical strength and resilience despite the slot, it is proposed that the width of the middle section of the mounting bracket increases in the direction of the side section having the slot. It can also be provided that the width of the side section having the slot increases in the direction of the side section end.

The invention further relates to a cover cap as described above and a mounting bracket also as described above.

The invention is explained below using exemplary embodiments based on the drawing. It shows:

Fig. 1 is an enlarged axial section of a cover cap;

Fig. 2 a cross-section of an assembled guide rail in the area of a fastening screw with cover cap;

Fig. 3 shows a partially broken-off, enlarged section corresponding to Fig. 2 during the insertion of the cover cap;

Fig. 4 a section corresponding to Fig. 3 with

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inserted cover cap (detail A in Fig. 2);

Fig. 5 shows a section corresponding to Fig. 4, but with a modified cover cap;

Fig. 6 is a simplified isometric view of a guide rail with carriage and mounting brackets attached to the carriage;

Fig. 7 is a plan view of a mounting bracket;

Fig. 8 is a side view of the mounting bracket; and

Fig. 9 a front view of guide rail and carriage including mounting clamp.

The linear motion guide 10 shown in Fig. 6 consists of a guide rail 12 and a carriage 14 that is movably mounted along the guide rail 12. The guide rail 12 can be fastened to a support 16 indicated in Fig. 2, e.g. a machine frame, using at least two fastening screws 18 in the area of the two guide rail ends. In the case of particularly long guide rails or particularly high demands on the load-bearing capacity and linearity of the guide rail 12, this can also be fastened to the respective support using additional fastening screws between the guide rail ends.

The part to be moved linearly, for example a tool carrier or measuring device, can be fastened to the guide carriage 14, for example with the aid of fastening screws which are inserted into threaded holes 22 opening out on the upper side 20 of the carriage 14.

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can be screwed. The carriage 14 is supported in the usual way by rolling or roller elements on the rail 12. In Fig. 6, two closed ball orbits 24a and 24b are only symbolically indicated, the balls of which are supported by rolling on two inwardly inclined rolling surfaces 28a and 28b on the corresponding guide rail longitudinal side 30 (see Fig. 2). On the opposite side of the carriage, two further ball orbits (not shown) are indicated, the balls of which are in turn supported on the corresponding rolling surfaces 28a and 28b.

Rolling elements can also be used instead of balls.

To accommodate the aforementioned fastening screws 18, the guide rail 12 is provided with a corresponding, stepped through-opening 32, which opens into the cover surfaces 34 facing away from the carrier 16 and forming the upper side of the guide rail 12, forming a relatively sharp, circular edge 36.

The interior I of the slide, which is delimited by the U-shaped slide 14 in cross section and largely filled by the guide rail 12, is often sealed by a lip seal 3 8 on both end faces 40 of the slot 14, which essentially follows the outline of the guide rail 12. In this way, the penetration of dust or dirt particles or even workpiece chips into the interior I and thus into the area of the balls in the ball orbits 24a and 24b is prevented. At least in the case of those through openings 32 which are used during the

If the slide 14 passes over the sharp edges 36 during operation, there is a risk that dust, dirt or workpiece chips that have accumulated in this through-opening (above the heads 18a of the fastening screws 18) will penetrate into the interior of the slide I when the slide passes over. Passing over the sharp edge 36 also leads to increased stress or even damage to the lip seal 38.

To remedy this, the through openings 32 are each closed with a cover cap after the guide rail 12 has been mounted on the respective support 16. According to Fig. 1, this consists of a head plate 52 and a spreading foot 54. The top 50a of the head plate 52 is flush with the cover surface 34 when mounted, as can be seen from Figs. 2 and 4 or 5. The outline of the top 50a essentially corresponds to the outline of the mouth of the through opening 32 in the cover surface 34, so that a practically negligible annular gap is formed between the head plate 52 and the edge 36.

In the exemplary embodiments, the peripheral surface 50b of the head plate 52 is cylindrical. As indicated by dashed lines in Fig. 1, however, this can also be essentially conical towards the spreading foot 54. The outline of the upper side 50a remains unchanged, so that the same tight seal is achieved in the cover surface 34 as with a cylindrical design. Due to the conicity, the head plate 52 is easier to thread into the mouth of the recess 32 in the cover surface 34. At the end of the impact movement, a slight press fit can also be achieved between the upper edge area of the head plate 52 and the through-

An opening must be provided which excludes any annular gap.

With an upper diameter dl of the head plate 52 of 13.05 mm, a lower diameter dl'' of the head plate 52 of 12.80 mm and a bore diameter dl' of the through hole 32 in the area of the edge of 13.02 mm (with tolerance HlO), secure threading and possibly a slight press fit are achieved depending on the manufacturing accuracy.

The spreading foot 54 is formed by an annular wall 56 which protrudes from the underside 50c of the head plate 52 and widens conically in the direction away from the head plate 52. It is continuous in the circumferential direction, but can also be provided with at least one longitudinal slot if the holding forces of the cover cap within the through opening are not so high, for example to enable non-destructive disassembly of the cover cap 50. A hook-like circumferential projection 58 which protrudes radially outwards is formed on the free edge of the annular wall 56 and forms a ring-shaped protrusion. The circumferential projection 58 is tapered towards the end of the spreading foot, forming a correspondingly circular conical bevel 58a. This is followed by a relatively short cylindrical outer circumferential surface 58b towards the head plate 52. This is followed by a radially inwardly extending annular surface 58c, which ends at the actual annular wall 56.

The thickness d2 of the head plate 52 in the embodiment is 0.7 mm, the axial length d3 of the spreading foot is 1.7 mm; the wall thickness d4 of the ring wall is

0.5 mm, the radial width d5 of the radial ring surface 58c is 0.35 mm, the axial length d6 of the cylindrical outer peripheral surface 58b is 0.3 mm and the inclination angle α of the conical bevel 58a is approximately 45°. The inclination angle β of the ring wall 56 is approximately 105°.

The through opening 32 is stepped with a first section 32a, which adjoins the edge 3, and a second section 32b, whose diameter d7 is, for example, 12.55 mm and is therefore smaller than the already mentioned diameter dl' of the through opening 32 in the area of the edge 36 (= diameter of the first section 32a). Between the two sections 32a and 32b there is a connecting section 32c, which is conical in shape in order to produce a transition between the two sections 32a and 32b that is not too abrupt. The angle of inclination is slightly smaller than the angle of inclination α of the bevel 58a at the end of the spreading foot 54.

The outer diameter d9 of the circumferential projection 58 at 13 mm is therefore approximately 4% larger than the diameter d7 of the section 32b, so that in the assembled state the circumferential projection 58 arranged on the inner circumferential surface 60 of the second section 32b is accordingly pushed radially inwards with elastic and possibly also plastic deformation of the spreading foot 54. The resulting radial preload, with which the spreading foot 54 presses against the circumferential surface 60 of the second section 32b, defines the holding force of the cover cap 50 within the through opening 32.

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The assembly of the cover cap 50 is quick and easy. To do this, the cover cap 50 is inserted into the through hole 32 with the spreading foot 54 first. As long as the hook projection 58 is located within the first section 32a, insertion is easy due to the possibly slightly larger diameter d9 of the circumferential projection compared to the diameter dl' of the section 32a.

As soon as the circumferential projection 58 reaches the conical connecting section 32c, the cover cap 50 is self-centered in relation to the through-opening axis 64, since the spreading foot 54 is in line contact with the conical connecting section 32c, which is symmetrical to the axis 64. The head plate 52 is still above the cover surface of the guide rail 12. If the cover cap 50 is then pressed into the intended end position according to Fig. 4 after overcoming the corresponding resistance due to the radial compression of the spreading foot 54 after the transition into the reduced-diameter second section 32b, the head plate 52 threads into the mouth of the through-opening 32 symmetrically to the axis 64 due to the correct orientation of the cover cap 50. For this purpose, the foot length d3 must be so large that, during the described automatic centering of the cover cap 50 when the spreading foot 54 is in contact with the conical connecting section 32c according to Fig. 3, the underside 50c of the head plate 52 is at least slightly above the cover surface 34. This limit situation is indicated in Fig. 3, in which the outline of a correspondingly dimensioned guide rail 12' with cover surface 34' is indicated with a dash-dot line.

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The cover cap 50 can be driven into the desired position in which the upper side 50a is flush with the cover surface 34 with the aid of an intermediate plate 65 indicated by dashed lines in Fig. 2, which is struck with a press stamp or a striking tool until it strikes the cover surface 34 itself.

In the assembly position according to Fig. 4, the head plate 52 is spaced from the conical connecting section 32c. This prevents dimensional inaccuracies of the head plate, in particular its thickness d2, and of the connecting section 32c, in particular its axial position within the through hole 32, from leading to the cover cap not being exactly flush with the cover surface 34.

In those cases in which the cover cap 50 has to be particularly resilient, the cover cap thickness d2 can alternatively be adjusted to the axial length of the connecting section in such a way that, in the assembly position, the lower ring edge 66 of the head plate 52 rests just against the conical connecting section 32c or digs into the conical surface more or less strongly after the corresponding force is applied by the respective impact tool. Due to the elastic springback after the pressing-in process, the top side 50a of the cover cap 50 may have to be slightly leveled with the cover surface 34.

In the embodiments according to Fig. 2 to 4, however, the cover cap is supported exclusively with its circumferential projection 58 (annular tooth) radially against the corresponding inner circumferential surface 60 of the reduced-diameter second section 32b in order to

The axial compression of the ring and guide rail during the pressing process is comparatively very low and so is the springback. Leveling is generally not necessary.

The cover cap is easy to manufacture, especially as a machine-turned part. It is made of slightly softer metal than the guide rail, so that the guide rail is not damaged when the cover cap is installed and removed.

During the assembly and alignment of the guide rail 12 on the respective support 16, the difficulty arises that the chute 14 cannot be moved along the rail 12 in such a way that it passes over the still open through openings 32. The lip seals 38 on both front sides of the slide 14 were damaged by the sharp edge 36. To solve this problem, a mounting clamp 70 is attached to both front sides, as can be seen from Fig. 6-9.

The clamp 70 has an approximately U-shape in the cross-section of Fig. 8 with an upper side section 72, a middle section 74 and a lower side section 76. It consists of a spring sheet metal part 71 bent into a U-shape; the middle section 74 is additionally provided with a stiffening plate 78. The stiffening plate 78 is glued to the middle section 74 of the spring sheet metal part 71 or spot-welded to it. In its outline, the stiffening plate 78 follows the outside of the middle section 74.

- 21 section 74 exactly matches the outline of the central section 74.

The lower side section 76 has a rectangular outline. The middle section 74 including the interlocking plate 78, on the other hand, has an outline in the form of an isosceles trapezoid, the base line of which (the longer of the two parallel trapezoid lines) is at the top. The upper side section 72 is also trapezoidal in outline in a corresponding manner. In Fig. 7, the outline of the upper side section 72 folded into the plane of the drawing is indicated by a dashed line 72'. It can be seen that the trapezoidal sixth lines of the upper side section are a continuation of the trapezoidal side lines of the middle section 74.

The mounting bracket 70 is also provided with a slot 80, which, when mounted, serves to accommodate a front-side grease nipple 82 of the slide 14. The slot 80 runs from the middle section 74 upwards to the upper side section 72, where it opens out (see Fig. 7 and 8). The splicing plate 78 is also provided with a corresponding slot. The lower end of the slot is approximately 1/5 of the height of the middle section 74. The splicing plate 78 ensures that, despite this fairly wide slot, the mounting bracket is sufficiently mechanically stable and that, when the mounting bracket 70 is mounted on the slide 14, there is sufficient spring preload for reliable hold. At least one of the two side sections 72 and (in the illustrated embodiment, the lower side section 76) is bent slightly inwards in the relaxed state in order to exert sufficient spring force on the inner side 21 of the slide 14 parallel to the upper side 20 after assembly.

to exert sufficient spring force on the inner side 21 of the carriage 14 parallel to the upper side 20.

The height dimension hl of the middle section 74 corresponds essentially to the height dimension h2 (distance between surfaces 20 and 21) of the middle leg of the U-shape of the rubble 14 according to Fig. 9. As a result, the mounting clamp 70 can be easily pushed onto the front of the slide 14. This is also helped by the fact that, due to the stiffening function of the plate 78, the sheet thickness of the spring sheet metal part 71 that otherwise forms the mounting clamp can be comparatively small, in particular can be between 0.15 and 0.25 mm.

The pushed-on mounting bracket 70 lifts the lip seal 38 provided on the respective end face so far that it no longer comes into contact with the edge 36 of the respective through hole 32. The carriage can therefore be moved as desired on the guide rail 12 until it is adjusted accordingly. The corresponding fastening screw 18 (see also Fig. 2) can then be finally tightened and finally the respective through hole 32 can be closed, in particular with a cover cap as shown in Figs. 1 to 5. The two mounting brackets 70 are then removed on both end faces. The desired wiping effect of the lip seal 38, even in the area of the particularly easily soiled and therefore critical cover surface 34, is thus ensured.

Claims (27)

Expectations 1. Linear motion guide with a guide rail (12) and a carriage (14) supported on the guide rail (12) via roller or rolling elements, whereby the guide rail (12) is provided with at least one through-opening (32) for a fastening element, which can be closed by a possibly metallic cover cap (50) (18) for attaching the guide rail (12) to a support (16), wherein the through opening (32) opens into a cover surface (34) of the guide rail (12) facing away from the carrier and is arranged in the movement area of the carriage (14), characterized in that that the cover cap (50) has a head plate (52) adapted to the outline of the through-opening (32) and a spreading foot (54) which rests against a substantially cylindrical circumferential surface section (60) of the through-opening (32) under substantially radial prestress. 2. Linear motion guide according to claim 1, characterized in that the cover cap (50) is made of slightly less hard material than the guide rail (12). 3. Linear motion guide according to claim 1 or 2, characterized in that the peripheral surface of the head plate (52) is essentially cylindrical. 4. Linear motion guide according to claim 1 or 2, characterized in that that the circumferential surface of the head plate (52) tapers essentially conically towards the spreading foot (54). 5. Linear motion guide according to one of the preceding claims, characterized, that the diameter (dl') of a first section (32a) of the through-opening (32) receiving the head plate (52) is larger than the diameter (d7) of a second section (32b) of the through-opening (32) receiving the spreading foot (54). 6. Linear motion guide according to claim 5, characterized in that the first and the second section (32a, 32b) are each cylindrical, and that a connecting section (32c) between the first and the second section (32a, 32b) is essentially conical. 7. Linear motion guide according to one of the preceding claims, characterized, that the spreading foot (54) is provided on its outer circumference with a substantially conical bevel (58) tapering towards the spreading foot end. 8. Linear motion guide according to one of the preceding claims, characterized, that the spreader foot (54) is supported by a (52) protruding annular wall (56). 9. Linear motion guide according to claim 8, characterized in that the annular wall (56) expands substantially conically in the direction away from the head plate (52). 24 10. Linear motion guide according to claim 8 or 9, characterized in that the annular wall (56) is continuous in the circumferential direction. 11. Linear motion guide according to claim 8 or 9, characterized in that the annular wall is provided with at least one longitudinal slot. 12. Linear motion guide according to one of the preceding claims, characterized in that the spreading foot (54) is provided with at least one radially outwardly projecting hook projection in the region of its end remote from the head plate (52). 13. Linear motion guide according to claims 8 and 12, characterized in that the hook projection is formed by a circumferential projection (58) of the ring wall (56). 14. Linear motion guide according to one of claims 2 to 13, characterized in that the axial length (d3) of the spreading foot (54) is larger, preferably slightly larger, than the axial length of the first section (32a). 15. Linear motion guide according to one of claims 2 to 14, characterized in that the axial length of the first portion (32a) is greater than the thickness (d2) of the head plate (Fig. 4). 16. Linear motion guide according to one of claims 2 to 14, characterized, that the axial length of the first section (32a) is equal to or slightly smaller than the thickness (d3) of the head plate (52) (Fig. 5). 17. Cover plate (50) for a linear motion guide according to one of the preceding claims with a head plate (52) approximately adapted to the outline of the through opening (32) and a spreading foot (54) for a press fit in the through opening (32). 18. Linear motion guide (10) according to one of claims to 16 or the preamble of claim 1, characterized in that the carriage (14) provided with at least one lip seal (38) running along the cover surface (34) of the guide rail (12) can be provided with at least one mounting clamp (70) for lifting the lip seal (38) in the region of the opening of the at least one through opening (32) in the cover surface (34). 19. Linear motion guide according to claim 18, characterized in that the mounting clamp (70) can be attached to the front of the slide (14). 20. Linear motion guide according to claim 19, characterized in that the mounting bracket (70) is essentially U-shaped with a central section (74) for arrangement on a carriage front wall and two side legs (72,76) that are spring-loaded towards one another for spring-loaded contact with the carriage top (20) or on the underside of the carriage (21) between the carriage (14) and the guide rail (12). 21. Linear motion guide according to claim 20, characterized in that that the mounting clamp (70) has a substantially U-shaped spring plate part (71). 22. Linear motion guide according to claim 21, characterized in that that the middle section (74) of the U-shape of the spring sheet metal part (71) is provided with a stiffening plate (78). 23. Linear motion guide according to one of claims 18 to 22, characterized, that the mounting clamp (70) is provided with a receiving opening for a front-side grease nipple (82) of the slide (14). 24. Linear motion guide according to claim 23, characterized in that that the mounting bracket (70) is provided with a slot (80) to form the receiving opening, which opens out at one of the two side leg ends of the U-shaped mounting bracket (70). 25. Linear motion guide according to claim 24, characterized in that the width of the central portion (74) of the mounting bracket (70) increases in the direction of the side portion (72) having the slot. 26. Linear motion guide according to claim 25, characterized in that that the width of the side section (72) having the slot (80) increases in the direction of the side section end. 27. Mounting clamp (70) for a linear motion guide (10) according to one of claims 18 to 26 with a substantially U-shaped bent spring sheet metal part (71).