Abstract:
A linear guide unit has an elongated guide housing having a longitudinal axis and having walls bordering a guide cavity, with two side walls form a longitudinal opening of the guide cavity, a slider that is movably guided in the direction of the longitudinal axis on at least one guide track provided in the guide cavity and connectable with a unit to be moved by the linear guide unit through the longitudinal opening, a drive device for moving the slider in the direction of the longitudinal axis, a profiled channel attachable to the guide housing for housing functional elements, with the positive connection is additionally secured by frictional engagement or by snapping into place, wherein the profiled channel has at least one lateral mounting projection and is in holding contact via this mounting projection with the exposed end of a side wall or a part joined therewith.

Description:
BACKGROUND OF THE INVENTION 
   The invention concerns a linear guide unit, comprising an elongated guide housing having a longitudinal axis and walls bordering a guide cavity, i.e., a bottom wall and two side walls, whereby the two side walls form—between themselves—a longitudinal opening in the guide cavity opposite the bottom wall, comprising a slider that is movably guided in the direction of the longitudinal axis on at least one guide track provided in the guide cavity, whereby this slider is capable of being joined through the longitudinal opening with a unit to be moved by the linear guide unit, comprising a drive device for moving the slider in the direction of the longitudinal axis, and comprising a profiled channel capable of being attached to the guide housing for accommodating functional elements such as position sensors and the like. 
   Linear guide units of this type are made known in the brochure entitled “LM-Kompaktlineareinheit Typ KR” (LM Compact Linear Guide Unit, Model KR) from THK Co. Lt., and the applicant&#39;s brochure entitled “STAR-Linearmodule” (STAR Linear Module). In the case of the linear guide units made known in the THK brochure, the guide housing is designed as an outer rail, while the linear guide units described in the Star brochure comprise a conventional guide housing, in the case of which the at least one guide track is formed by an inner rail produced separately from the guide housing and secured in the guide cavity. With these two types of linear guide units, a profiled channel can be attached to the guide housing, which said profiled channel serves to accommodate the most diverse types of functional elements, such as sensors for detecting the position of the slider. In practice, users complain that fastening said profiled channels to the guide housing is extremely troublesome. 
   SUMMARY OF THE INVENTION 
   The object of the present invention, therefore, is to provide a linear guide unit of the type according to the general class, in the case of which the profiled channel can be fastened to the guide housing quickly and easily. 
   This object is obtained, according to the invention, by means of a linear guide unit of the type described initially, in the case of which the profiled channel comprises at least one lateral mounting projection, and the profiled channel is in holding contact via this mounting projection with the exposed end of a side wall or a part joined therewith. According to the invention, the profiled channel—to be mounted on the guide housing with its at least one lateral mounting projection—need only be pushed onto the exposed end of a side wall of the guide housing. To accomplish this, only a few simple manual steps are required, so that it takes little time to mount the profiled channel on the guide housing. 
   Preferably, the mounting projection can be designed as a mounting flange extending essentially across the entire length of the profiled channel. To this end, the profiled channel can be extruded in simple fashion as an extruded profile made of plastic or the like. It is also possible, however, to produce the profiled channel as an injection-molded part. 
   In particular when the linear guide unit is positioned horizontally, it can be sufficient for the mounting projection to be positively engaged with the exposed end of the side wall or the part joined therewith. In order to position the linear guide unit vertically or tilted toward the horizontal plane, however, the positive connection can be additionally secured by means of a friction connection, e.g., using a clamping element, preferably a clamping screw, or by snapping it into place. To make the “snapping into place” possible, a locking nose can be provided, e.g., on the lateral mounting projection of the profiled channel, which said locking nose engages in an associated snap-in recess of the guide housing or a part joined therewith. 
   In order to ensure that the profiled channel is held—via the positive engagement—as securely as possible against the side wall or the part joined therewith, it is proposed in a further development of the invention that the underside of the mounting projection lie on at least part of the end surface of the exposed end of the side wall or the part joined therewith. Additionally or as an alternative, the exposed end of the side wall or the part joined therewith, on the one hand, and the mounting projection on the other hand are designed to complement each other, at least in sections. For example, on one of the two parts—on the mounting projection on the one hand or the exposed end of the side wall or the part joined therewith on the other hand—at least one projection is provided that is capable of being gripped from behind by an associated hook element provided on the respective other part—the exposed end of the side wall or the part joined therewith on the one hand, or the mounting projection on the other—or it is capable of being encompassed by eyelet element, or, on one of the two parts—the mounting projection on the one hand or the exposed end of the side wall or the part joined therewith on the other hand, at least one recess is provided, into which an associated engaging element provided on the respective other part—the exposed end of the side wall or the part joined therewith on the one hand, or the mounting projection on the other—is capable of being inserted. 
   Finally, it can be further advantageous if the profiled channel bears against an outer surface of the side wall or the part joined therewith, and is supported there, for example. 
   As previously discussed with regard for the Star brochure mentioned hereinabove, the at least one guide track can be formed on a guide rail produced separately from the guide housing and secured in the guide cavity. The invention can also be used advantageously, however, with a linear guide unit of the type disclosed in the THK brochure mentioned hereinabove, i.e., a linear guide unit, in the case of which the guide housing is designed as an outer rail. 
   In conjunction with the present invention, an “outer rail” is understood to mean a guide housing, in the case of which the at least one guide track is provided on an inner surface—facing the guide cavity—of at least one of the walls of the guide housing, and not on a guide rail usually extending from the bottom wall of the guide housing into the guide cavity. The guide track can be formed on a guide track insertion element, however, that is attached to an inner surface of one of the walls of the guide housing, preferably located in a groove formed in one of the walls. Due to this outer rail design, the slider can have a compact, substantially rectangular cross section, i.e., it does not have indentations, in particular, to grip the guide rail, as is the case with the linear guide unit made known in DE 38 15 595 A1, for example. 
   The guide rail can be made, preferably, of hardened steel. If guide track insertion elements are used, it is sufficient, however, to make these insertion elements out of steel, while the outer rail can be produced, e.g., as a profile-extruded aluminum section. 
   To fasten the outer rail to a superimposed structural unit, through holes for fastening elements, preferably clamping screws, can be provided, e.g., in the bottom wall of the outer rail. Additionally or as an alternative, it is also possible for the outer rail to be fastenable to a superimposed structural unit by means of clamping components, whereby the clamping components interact with a clamping surface facing away from the superimposed structural unit. In the latter case, it is advantageous in terms of saving space if the clamping surface is part of the bounding face of a clamping recess, preferably a fastening groove, that is provided in the region of at least one transition of the bottom wall and one of the side walls in the outer surface of the outer rail. The aim is to provide an independent safeguard when linear guide units with an outer rail are fastened using clamping components. 
   To furnish a precision linear guide unit, it is proposed that the slider be supported on the at least one guide track by means of a recirculating rolling element, which is known per se from the related art. 
   To ensure that the slider is supported on the outer rail securely in all load directions, it is proposed that each side wall of the outer rail comprise at least two guide tracks on its inner surface facing the guide cavity, whereby the pressure lines of the guide tracks form an “X” shape. 
   In the case of a linear guide unit in which the drive device comprises a recirculating-rolling element screw and nut having a threaded spindle that is supported immovably in the direction of the longitudinal axis at the longitudinal ends of the outer rail, but in a fashion that allows it to turn around a spindle axis extending substantially parallel to the longitudinal axis, and having a threaded nut that is part of the slider, it is further proposed that the spindle axis—when the bottom wall of the outer rail extends substantially horizontally—is located above the horizontal plane that extends through the intersection points of the pressure lines of the guide tracks. As a result, the torque that is produced by the axial force exerted by the unit to be moved and the counterforce of the spindle, is kept at an acceptably low level. The clearance between the spindle axis and the plane extending through the intersection points of the pressure lines of the guide tracks can measure at least 2 mm, for example. 
   The aim is to provide an independent safeguard for this exemplary embodiment in conjunction with linear guide units having an outer rail. 
   Furthermore, in the case of such a linear guide unit driven by a recirculating-rolling element screw and nut, the threaded nut can be formed as a unit produced separately from the slider, and said threaded nut can be inserted in an axial passage of the slider. For this exemplary embodiment as well, the aim is to provide an independent safeguard in conjunction with linear guide units having an outer rail. It has the advantage that, by furnishing a number of sliders having differently-formed outer guides on the one hand and a number of threaded spindle/threaded nut units having different designs, on the other hand, a large variety of different types and linear guide units can be offered depending on the special application, and one is therefore able to respond individually to a customer&#39;s specific needs. 
   Even when the drive device comprises a recirculating-rolling element screw and nut having a separately-designed threaded nut, the maintenance work on the linear guide unit can be simplified by providing one common central lubricator for the guide tracks and/or the recirculating rolling elements associated therewith, and for the drive device. 
   The aim is to provide an independent safeguard for this exemplary embodiment as well in conjunction with linear guide units having an outer rail. 
   The invention can also be used advantageously with linear guide units equipped with other types of drive devices, e.g., with linear guide units having a belt drive, in particular a toothed belt drive, or with linear guide units having a rack-and-pinion drive. 
   Various embodiments of the linear guide unit according to the invention are also feasible with regard for the covering of the longitudinal opening of the guide cavity. For example, said longitudinal opening can be left uncovered, as is the case with the linear guide units shown on the cover page of the THK brochure mentioned hereinabove, for example. Moreover, it is also possible to cover the longitudinal opening of the guide cavity using a cover plate. 
   Finally, it is also feasible to cover the longitudinal opening of the guide cavity using a sealing strip, e.g., a steel strip, as was made known in DE 38 06 354 A1, for example. 
   The aim is to provide an independent safeguard as well when a linear guide unit having an outer rail is covered by means of a cover strip. 
   The sealing strip can be guided through a table unit fastened to the slider, and it can be secured to the longitudinal ends of the outer rail. It is also feasible in principle, however, for the sealing strip to be secured at both axial ends of the slider and move together with said slider in the longitudinal direction of the linear guide unit. The sealing strip can be guided—starting at an axial end face of the slider—around return pulleys as a sealing strip loop to the other axial end face of the slider. Finally, and as an alternative, it is also possible to use two sealing strips, each of which is guided toward a winding mechanism on the axial longitudinal ends of the linear guide unit, as used similarly in roller shutters. 
   In the case of a sealing strip situated in the direction of the longitudinal axis of the guide housing, it is proposed in a further development of the invention that the sealing strip rest on two profiled rails located on the end faces of the side walls of the outer rail. When the sealing strip is designed as a steel strip, it is further advantageous if the profiled rails are made of a non-magnetic and, preferably, non-magnetizable material such as aluminum, since this steel strip can then be held tightly against the profiled rails by means of at least one magnet or magnetic strip located in at least one of the profiled rails. 
   With regard for the fastening—in accordance with the invention—of the profiled channel to the exposed end of a side wall of the guide housing and/or the outer rail or a part joined with this side wall (the profiled rail in this case), it is particularly advantageous if the shape of a surface facing away from the end face of the side wall of the outer rail of at least one of the profiled rails is substantially identical to this end face. In this case, the same profiled channel can then be used with all cover variants of the linear guide unit according to the invention. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be explained in greater detail hereinbelow using exemplary embodiments with reference to the attached drawings. 
       FIG. 1  is an orthogonal sectional view of a linear guide unit according to the invention; 
       FIG. 2  is a detained view of  FIG. 1  to explain the fastening of the profiled channel to the guide housing; 
       FIGS. 3 and 4  are views similar to  FIG. 2  having alternative fastening means for the profiled channel; 
       FIG. 5  is a view similar to  FIG. 1  having a linear guide unit comprising a strip cover; and 
       FIG. 6  shows a linear guide unit according to the invention having a plate cover. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   A linear guide unit in general according to the invention is labelled with numeral  10  in FIG.  1 . It comprises a guide housing  12  extending in the direction of a longitudinal axis L (orthogonal to the plane of the drawing) having a bottom wall  12   a  and two side walls  12   b  projecting substantially orthogonally from said bottom wall, which said side walls, together with the bottom wall, form the borders of a guide cavity  12   c . The exposed ends  12   b   1  of the side walls  12   b  define a longitudinal opening  12   d  of the guide cavity  12   c  between them. 
   In the exemplary embodiment shown, the guide housing  12  is designed as an outer rail. To accomplish this, guide tracks  14  are formed in the inner surfaces of the side walls  12   b  facing the guide cavity  12   c , on which said guide tracks a slider  16  located in the guide cavity  12   c  is movably guided in the direction of the longitudinal axis L by means of recirculating rolling elements  18 , in particular recirculating balls. The end plates comprising the internal grooves of these recirculating rolling elements  18  are labelled  18   a  in FIG.  1 . 
   In order for the guide housing  12  to have sufficient stiffness and stability to guide the slider  16 , it is preferably made of hardened steel. A unit  17  to be moved by the linear guide unit is mounted on the slider  16 . 
   In the exemplary embodiment shown in  FIG. 1 , a recirculating-rolling element screw and nut  20  having a threaded spindle  20   a  extending in the longitudinal direction L essentially over the entire length of the guide housing and/or the outer rail  12  is provided to advance the slider  16  and, therefore, the unit  17  to be moved, in the direction of the longitudinal axis L, which said threaded spindle is supported substantially immovably in the axial direction in (not shown) terminal crossmembers of the guide housing  12  by means of a fixed bearing and a movable bearing, but in a manner that allows it to turn around a spindle axis S extending essentially parallel to the longitudinal axis L. A threaded nut  20   b  associated with the slider  16  is guided on the threaded spindle  20   a  by means of one or more recirculating rolling elements in a manner that is known per se. 
   According to the invention, the threaded nut  20   b  is produced as a separate part from the slider  16 , and it is inserted in a spindle passage  16   a  of this slider in torsion-resistant, axially-fixed fashion. As a result, based on a number of basic slider details that differ, e.g., in terms of the design of the guidance on the outer rail  12 , and a number of threaded nuts  20   b  having different designs, a great number of different types of sliders  16  can be offered to the customer, even though only a comparably small number of different component types must be kept in inventory. 
   To simplify the maintenance to be performed on the linear guide unit according to the invention, moreover, one central lubricating system is provided, despite the fact that the slider  16  and threaded nut  20   b  are designed as separate components, which said lubricating system supplies—via a central lubricating connection  22  shown only schematically with dashed lines—the recirculating rolling elements  18  as well as the recirculating-rolling member screw and nut  20  with lubricant, preferably grease or oil. 
   A further point that is essential to the invention can be seen in the arrangement of the spindle axis S of the recirculating-rolling member screw and nut  20  relative to the guide tracks  14  to linearly guide the slider  16  along the outer rail  12 . In fact, the guide tracks  14  are formed on the inner surfaces of the side walls  12   b  of the outer rail  12  in such a manner that their pressures lines D form an “X” shape. The straight lines G extending through the intersection points of the pressure lines D essentially parallel to the longitudinal axis L span a plane indicated in  FIG. 1  with dashed lines. According to the invention, it is now provided that the spindle axis S of the recirculating-rolling member screw and nut  20  is located on the side of this plane E facing away from the bottom wall  12   a  of the outer rail  12  and, in fact, at a predetermined distance d from said plane, whereby this distance d advantageously measures at least 2 mm. 
   To secure the outer rail  12  to a superimposed structural unit  24 , e.g., a mounting plate, through holes  12   e  are provided in the bottom wall  12   a  of the outer rail  12 , into which, e.g., clamping screws can be inserted. Moreover, fastening grooves  12   f  having clamping surfaces  12   g  are provided in the outer surface of the guide housing  12  in the region of the transition of the bottom wall  12   a  into the side walls  12   b , into which (said fastening grooves) clamping noses  26   a  of clamping components  26  can be inserted. These clamping components can also be fastened to the superimposed structural unit  24  by means of threaded bolts  28 . To make clamping possible, the clamping components  26 —on their ends furthest away from the outer rail  12 —comprise at least one support foot or a support strip  26   b  that holds the rest of the clamping component  26  at a slight distance away from the surface of the superimposed structural unit  24 , so that, when the clamping bolt  28  is tightened, the clamping nose  26   a  can be brought tightly into clamping engagement with the clamping surface  12   g.    
   To accommodate a number of functional units, e.g., position sensors  30 , that interact with an associated position indicator  31  attached to the slider  16  or the unit  17  to be moved, a mounting channel  32  is provided that is located in the region of the exposed ends  12   b   1  of the side walls  12   b  of the outer rail  12 . The details of the design of the mounting channel  32  and its attachment to the side walls  12   b  will be described in greater detail hereinbelow with reference to the enlarged illustration shown in FIG.  2 : 
   The housing channel  32  comprises a hollow profile  32   a  that serves to accommodate the functional units, e.g., position sensors  30  or electrical leads  34 , and it comprises a mounting flange  32   b  attached to the upper end of the hollow profile  32   a  and projecting laterally away from the hollow profile  32   a . The mounting flange  32   b  comprises a peg  32   b   1  pointing away from the hollow profile  32   a  and a peg  32   b   2  bent essentially orthogonally in relation to said peg  32   b   1 . With the hook formed by these pegs  32   b   1  and  32   b   2 , the housing channel  21  can be placed on the end face  12   h  of the side wall  12   b  and hooked over a mounting projection  12   b   2  there. When the profiled channel  23   a  bears laterally against the outer surface  12   b   3  of the side wall  12   b , as shown in  FIGS. 1 and 2 , the positive engagement of the holding flange  32   b  with the holding projection  12   b   2  is fully sufficient to secure the housing channel  32  to the outer rail  12 , when the longitudinal guide unit  10  is positioned horizontally. 
   To secure this positive engagement, various other measures acting with frictional or non-positive engagement can be used as well. For example, the bent-over peg  32   b   1  can lock into place with the holding projection  12   b   2  while utilizing the natural elasticity of the housing channel  32 —made preferably of plastic—as indicated by reference numeral  36  in FIG.  2 . To accomplish this, a locking nose or a locking strip can be provided on the peg  32   b   2 , and a snap-in recess or a snap-in groove can be provided on the holding projection  12   b   2 . 
   It is also possible, however, to clamp the holding flange  32   b  with the holding projection  12   b   2 . To accomplish this, for example, the mounting flange  32   b  can be designed in such a fashion, for example, that the recess formed between its main body  32   b   3  and the peg  32   b   2 —the base of which forms the peg  32   b   1 —is designed to be slightly smaller than actually required to accommodate the holding projection  12   b   2 . When the mounting flange  32   b  is slid onto the holding projection  12   b   2 , the hook element  32   b   1 / 32   b   2  is therefore spread apart and, due to the natural elasticity of the material of the mounting flange  32   b , it clamps onto the holding projection  12   b   2 . 
   Finally, it is also feasible to screw clamping screws, preferably set screws  38 , into the main body  32   b   3  of the holding flange  32   b , which said clamping screws are supported against a side wall of the holding projection  12   b   2 , and pull the peg  32   b   2  into fixed contact against the other side wall of the holding projection  12   b   2 . 
   The further design of the housing channel  32 , in particular the hollow profile  32   a , is known per se, and will therefore not be described in greater detail here. 
   The positive attachment of the profiled channel  32  using the mounting flange  32   b  can also be accomplished in another manner, of course, as shown in  FIG. 2. A  few further means for fastening shall be explained hereinbelow with reference to  FIGS. 3 and 4 . 
   According to  FIG. 3 , the mounting flange  132   b  comprises a plurality of passages  132   b   4  that can be placed on the corresponding holding projections  112   b   2  on the end face  112   h  of the side wall  112   b . Moreover, it is possible, according to  FIG. 4 , for the peg  232   b   2  of the hook element  232   b   1 / 232   b   2  of the mounting flange  232   b  to be inserted in a holding recess  212   b   2  formed in the end face  212   h  of the side wall  212   b . It possible, on the one hand, that the holding recess  212   b   2  is a longitudinal groove extending continuously in the longitudinal direction L, or, as an alternative, it is also possible to provide a plurality of such holding recesses  212   b   2  in which a corresponding plurality of hook elements  232   b   1 / 232   b   2  engages. With regard for the exemplary embodiment according to  FIG. 3  as well as the exemplary embodiment according to  FIG. 4 , furthermore, clamping means can be provided, as were described hereinabove with regard for the example of the exemplary embodiment according to FIG.  2 . Representative thereof, fixing screws  138  and  238  are indicated using dashed lines in  FIGS. 3 and 4 . 
   The linear guide unit according to the invention can also have different designs with regard for the covering of the guide cavity  12   c . For example, the guide cavity  12   c  of the linear guide unit  10  according to  FIG. 1  does not have a cover at all. 
   In the case of the linear guide unit  310  according to  FIG. 5 , on the other hand, the longitudinal opening  312   d  of the guide cavity  312   c  of the outer rail  312  is covered by means of a covering strip  340 , as made known, e.g., in DE 38 06 354 A1 for linear guide units having inner rails. The cover strip  340  is secured at its two longitudinal ends to the terminal crossmembers (not shown)—mentioned hereinabove—of the outer rail  312  and is guided through a longitudinal passage of the table  317  mounted on the slider  316 . 
   In the regions in front of and behind the table  317 , the cover strip  340  lies on profiled strips  342  that are placed on the end faces  312   h  of the exposed ends  312   b  of the outer rail  312  and are preferably made of aluminum. Magnetic elements  344  are located in the region of the facing exposed ends  342   a  of the profiled strip  342 , which said magnetic elements attract the cover strip  340 —preferably made of steel—and therefore ensure a reliable sealing-off of the guide cavity  312   c . A plurality of magnetic elements  344  can be distributed across the length of the outer rail  312 , and a magnetic strip or an arrangement of magnetic strips can be provided that extends continuously across the length of the outer rail  312 . 
   So that the housing channel  332  can still be secured in the usual fashion using its mounting flange  332   b  despite the arrangement of the profiled strip  342  on the end faces  312   h  of the exposed ends  312   b  of the outer rail  312 , a surface  342   b  of the profiled strips facing away from the end face  312   h  of the side wall  312   b  of the outer rail  312  is designed—at least as far as the mounting and/or holding devices for the housing channel  332  are concerned—exactly like the exposed end  312   b  of the outer rail  312  in the region of the end face  312   h . That is, in the case of the mounting variant shown in  FIGS. 1 and 2 , a holding projection  342   c  is formed on the surface  342   b  of the profiled rails  342 , the shape of which is essentially identical to that of the holding projection  312   b   2 . 
   As a result, starting with exactly the same outer rail  312 , a linear guide unit  10  without a cover (refer to FIG.  1 ), a linear guide unit  310  having a strip cover (refer to FIG.  5 ), as well as a linear guide unit  410  having a plate cover (refer to FIG.  6 )—which will be explained next—can be realized, whereby it is simultaneously ensured that exactly the same kind of housing channel can be used and secured to the outer rail or a part joined therewith, i.e., the profiled rail. 
   As indicated many times hereinabove, the linear guide unit according to the invention as shown in  FIG. 6  can also be designed as a linear guide unit  410  having a plate cover. The cover plate  450  provided for this is fastened at the two longitudinal ends of the outer rail  412 , e.g., in the region of the terminal crossmembers (not shown) that support the threaded spindle. Open gaps  452  exist between the exposed end  412   b  of the outer rail  412  and the cover plate  450  that are designed large enough so that, on the one hand, mounting arms  454  of the slider  416  or a part  417  mounted thereon can be guided through it from out of the guide cavity  412   c  and joined there with a functional unit to be moved by the linear guide unit  410 , and, on the other hand, sufficient space is available to attach the housing channel  432 , which, in this case as well, is hooked onto a holding projection  412   b  of the exposed end  412   b  of the outer rail  412 .