DESCRIPTION OF THE RELATED ART The present invention is directed to improvements in linear motion bearing assemblies. In particular, the improvements relate to linear motion bearing assemblies of the type which support a carriage or pillow block for linear movement along a support member, for example, an elongated shaft or spline, profiled rails or radial bearings. These bearing assemblies can either be of the open type or the closed type.

Some of the known bearing assemblies typically include an outer housing and a ball retainer dimensioned for insertion into the outer housing. The ball retainer has a plurality of ball tracks in a loop configuration for containing and recirculating bearing balls. The ball tracks include open portions which facilitate load transfer from the supporting shaft to load bearing structure such as load bearing plates operatively associated with either the ball retainer or the outer housing. Return portions of the ball tracks permit continuous recirculation of the bearing balls through the ball tracks during linear motion.

In some embodiments, the ball retainer is formed as a monolithic element with the ball tracks integrally incorporated therein. See, U. S. Patent No.

3,767,276 to Henn. This structure, however, is difficult to efficiently manufacture because of the complex molds required. Also, these ball retainers, prior to insertion into a mounting carriage or outer housing are necessarily open and thus exposed to ambient conditions and contaminants such as dust and dirt. Such exposure could deleteriously affect the operation and life of the bearing assembly as well as the support structure on which it moves.

Self-contained linear bearing units are also known in the art. See, e. g.

U. S. Pat. No. 4,815,862 to Mugglestone et al. This unit, while representing a marked improvement in the art, still requires the use of end caps to engage the load bearing plates of the bearing segments. Further, the load bearing plates must be precisely machined to properly interfit with the end caps. This configuration adds to the expense and complexity of the bearing.

The load bearing structure may be in the form of integral elements formed on an inner radial surface of the outer housing. Typical bearing assemblies utilizing load bearing structure formed in the outer housing are shown, for example, in commonly owned U. S. Pat. No. 5,046,862 to Ng, the disclosure of which is incorporated herein by reference.

The outer housing of existing bearing assemblies is typically in the form of a one piece hollow steel cylinder which serves to, inter alia, retain and protect the ball retainer and balls. See, for example, U. S. Pat. Nos. 5,046,862 to Ng and 3,767,276 to Henn, discussed above. While useful, this type of outer housing increases the weight and expense of the bearing assembly.

Ball retainers assembled from interengageable self-contained ball retainer segments are also known. For example, commonly owned U. S. Patent No.

5,613,780, the disclosure of which is herein incorporated by reference, discloses one preferred embodiment of a ball retainer having a plurality of ball retainer segments.

Each ball retainer segment includes a separately fabricated inner and outer portion formed from separate dies. The above ball retainer segments, however, result in added assembly costs that are due to the precision and labor intensive assembly required for installation of the separately fabricated components, particularly, when smaller sized bearings are used.

Accordingly, it is one object of the present invention to provide a linear motion bearing which can'be easily and efficiently manufactured and assembled for various linear motion bearing applications.

It is another object of the present invention to provide a linear motion bearing assembly which is formed from metal or polymers and decreases the number of components and production costs of the bearing assembly.

It is yet another object of the present invention to provide a low cost, light weight monolithically formed ball retainer of a linear motion bearing assembly having a lower capitol cost for bearing production and a configuration which offers simple assembly and flexibility.

SUMMARY OF THE INVENTION The present invention provides a linear motion bearing subassembly monolithically fabricated from an engineering plastic or metal and configured so that forming, manufacture, handling and assembly complexity are reduced. The bearing subassembly structure includes a monolithically formed outer member and inner member similar to a two part bearing, thereby decreasing the number of separate components. The bearing subassembly structure provides for use of a two part die to form a bearing assembly which reduces the need for multiple dies, machining operations, as well as difficult assembly methods. The monolithically formed bearing subassembly offers a lower capital cost for bearing production and a structure offering simple assembly and flexibility for various bearing types. These monolithic bearing structures can be used for applications with round shafts or profile rails or even radial bearings, etc. This bearing subassembly structure also lends itself to assembly automation.

In one embodiment, a linear motion bearing subassembly is disclosed including a ball retainer with a monolithically formed continuous strip of inner portions and a monolithically formed continuous strip of outer portions. Each of the inner portions may define at least one ball track having a load bearing portion and a return portion. Each of the outer portions may define a load bearing plate aperture.

Preferably, each of the outer portions define an aperture having a pair of projections extending into the aperture and the load bearing plate includes a pair of longitudinal grooves dimensioned and configured to snap fit the load bearing plate into an operative position in the aperture.

A load bearing plate may be positioned in the load bearing plate aperture of each of the outer portions adjacent the load bearing portion of the ball track and a plurality of rolling elements may be disposed in the ball track for transmitting load from a load source and facilitating movement of the linear motion bearing subassembly. Preferably, the continuous strip of inner portions are monolithically formed with the continuous strip of outer portions. An end of the continuous strip of inner portions may be attachable to an end of the continuous strip of outer portions. Desirably, the ends may be removably attached.

The present disclosure also provides a novel and efficient assembly process for assembling linear motion bearing assemblies. This process includes the step of providing a ball retainer with a continuous strip of inner portions and a continuous strip of outer portions; rolling the inner portions; loading a plurality of bearing balls into a ball track of each of the inner portions; and rolling the outer portions about the inner portions in cooperative engagement therewith to form the linear motion bearing assembly.

In an alternate embodiment, the above disclosed process includes the steps of mounting a retainer onto the ball retainer to maintain the linear motion bearing assembly in a desired orientation. Most preferably, the step of rolling the inner portions includes rolling the inner portions in a first direction and the step of rolling the outer portions includes rolling the outer portions in a second direction.

In an alternate embodiment, the linear motion bearing subassembly includes a ball retainer formed of at least one self-contained ball retainer segment.

The ball retainer may include multiple self-contained ball retainer segments. The ball retainer may be, for example, substantially cylindrical or substantially rectangular.

The ball retainer segment includes at least one inner portion whereby each of the at least one inner portions may define at least one ball track having a load bearing portion and a return portion. At least one outer portion is included whereby each of the at least one outer portions may define a load bearing plate aperture. A load bearing plate may be positioned in the load bearing plate aperture of each of the at least one outer portions such that the load bearing plate is positioned adjacent to the load bearing portion of the ball track. A plurality of bearing balls may be disposed in the ball track for transmitting load from a load source to the load bearing plate facilitating movement of a linear motion bearing assembly along the load source.

At least one of the at least one inner portions is monolithically formed with at least one of the at least one outer portions to form at least one self-contained ball retainer segment. Each of the self-contained ball retainer segments may include a load bearing plate engagement structure positioned in a perimeter portion of the load bearing plate aperture for engaging the load bearing plate positioned therein. Each of the inner portions and each of the outer portions may snap fit together to form each of

the at least one self-contained ball retainer segments. Preferably, at least one inner portion is monolithically formed with at least one of the at least one outer portions by a flexible hinge. The flexible hinge may be, for example, continuous or intermittent.

In another embodiment, the ball retainer is formed of arcuate interengageable self-contained ball retainer segments. Preferably, each of the arcuate interengageable self-contained ball retainer segments includes at least one groove formed in an outer arcuate surface thereof and a retainer is positionable in the groove therein. The retainer assists in holding the arcuate interengageable self-contained ball retainer segments in a substantially cylindrical configuration. Most preferably, a portion of the retainer extend the outer arcuate surface of the interengageable self- contained ball retainer segment. Desirably, the arcuate interengageable segments each define an arc of 1200.

In another alternate embodiment, at least one inner portion is monolithically formed with at least one outer portion. The inner portion is hingedly connected to the outer portion such that folding manipulation forms a linear motion bearing subassembly.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, referred to herein and constituting a part hereof, illustrate the preferred embodiments of the linear motion bearing subassembly of the present invention and, together with the description, serve to explain the principles of the invention.

FIG. 1 is a perspective view of a ball retainer including a continuous strip of inner portions and a continuous strip of outer portions and having a retaining element in accordance with one embodiment of the present invention; FIG. 2 is a perspective view showing a linear motion bearing subassembly including the ball retainer shown in FIG. 1 having a load bearing plate and a plurality of ball bearings disposed in a ball track; FIG. 2A is a perspective view showing an alternate embodiment of a ball retainer having a continuous strip of inner portions being separately attachable to a continuous strip of outer portions; FIG. 3 is a perspective view showing a ball retainer including a continuous strip of inner portions and a continuous strip of outer portions for a reverse roll assembly in accordance with another embodiment of the present invention; FIG. 4 is a perspective view showing assembly of the ball retainer of FIG. 3 having a load bearing plate and a plurality of ball bearings disposed in a ball track to form a linear motion bearing subassembly;

FIG. 5 is a perspective view showing an alternate embodiment of a ball retainer segment having an inner portion formed with an outer portion and a plurality of bearing balls; FIG. 6 is a perspective view showing assembly of the ball retainer segment of FIG. 5 and a bearing plate; FIG. 7 is a perspective view of an alternate embodiment of a linear motion bearing subassembly having a substantially cylindrical configuration; FIG. 8 is a perspective view of an alternate embodiment of a linear motion bearing subassembly having a substantially rectangular configuration; FIG. 9 is a perspective view showing a ball retainer segment having an inner portion and an outer portion formed by a continuous living hinge; FIG. 10 is a perspective view showing a ball retainer segment having an inner portion and an outer portion formed by an intermittent living hinge; FIG. 11 is a cross-sectional view of the ball retainer segment shown in FIG. 9; FIG. 12 is an exploded perspective view of a closed-type linear motion bearing subassembly in accordance with the present invention supporting a linear shaft; and FIG. 13 is an exploded perspective view of an alternate embodiment of an open-type linear motion bearing subassembly supporting a linear shaft.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS Referring now to the drawings, wherein like reference numerals identify similar structural elements of the subject invention, there is illustrated in FIGS. 1 and 2 a linear motion bearing subassembly having a monolithic ball retainer for use in a closed-type linear motion bearing assembly 20 constructed in accordance with one embodiment of the present invention. Linear motion bearing assembly 20 (FIG. 2) has a linear motion bearing subassembly 22 including a monolithic ball retainer 30 with a monolithically formed continuous strip 40 of inner portions 42 and a monolithically formed continuous strip 44 of outer portions 46. As shown in FIG. 2, each inner portion 42 engages and overlays onto a corresponding outer portion 46 to form a self-contained ball retainer segment 32 of ball retainer 30. Ball retainer 30 may include a multiplicity of ball retainer segments 32 according to the number of corresponding inner and outer portions.

FIGS. 1 and 2 show inner portions 42 monolithically formed, forming the continuous strip 40, by living hinges 48 located between the individual inner portions 42. Outer portions 46 are monolithically formed, forming the continuous strip 44, by living hinges 50 located between the individual outer portions 46. Living hinges 48 and 50 define openings 49 therein, for increased flexibility continuous strip 40 of inner portions 42 and continuous strip 44 of outer portions 46, providing for facile assembly of ball retainer 30 about a linear shaft 99 (FIG. 2). Living hinges 48 and 50 may also provide a continuous monolithic formation of the continuous strip of inner portions 42 and outer

portions 46, similar to that shown in FIGS. 5 and 6. It is also contemplated that living hinges 48 and 50 may have an intermittent monolithic formation, similar to that shown in FIG. 10.

Referring to FIGS. 1 and 2, an inner portion end 51 of continuous strip 40 is monolithically formed with an outer portion end 52 of continuous strip 44 by a living hinge 53 forming monolithic ball retainer 30. The monolithic formation of continuous strip 40 and continuous strip 44 facilitate assembly of monolithic ball retainer 30 about linear shaft 99. Living hinge 53 is a flexible member monolithically formed as part of monolithic ball retainer 30.

In alternate embodiment, continuous strip 40 of inner portions 42 and continuous strip 44 of outer portions 46 may be separately attachable components of ball retainer 30, as shown in FIG. 2A. In FIG. 2A, an inner portion end 51 of continuous strip 40 is connected to an outer portion end 52 of continuous strip 44 to form ball retainer 30 which may be used in linear motion bearing assembly applications, similar to the subassembly in FIGS. 1 and 2. At least two adjacent inner or outer portions are monolithically formed. The connection of inner portion end 51 and outer portion end 52, shown in FIG. 2A, may be facilitated by a snap fit, pins, grooves, adhesives, etc. It is also contemplated that continuous strip 40 and continuous strip 44 may be removably attachable components of ball retainer 30.

Referring to FIGS. 1 and 2, each of inner portions 42 defines at least a portion of ball track 54 therein. Ball track 54 includes a load bearing portion 56 and a return portion 58 interconnected by turnarounds 60. Each of outer portions 46 are configured to engage and overlay onto corresponding inner portions 42 to form ball retainer segment 32 (FIG. 2) and include a load bearing plate mounting aperture 62.

Inner portions 42 and outer portions 46 engage through flush contact between an outer surface 43 of each of inner portions 42 and an inner surface 47 of each of corresponding outer portions 46. Alternate engagement mechanisms are contemplated to enhance the cooperative engagement and overlay of inner portions 42 and outer portions 46, such as, snap fit, pins, grooves, adhesives, etc. and are within the scope of knowledge of one skilled in this art.

As shown in FIG. 2, a load bearing plate 64 is dimensioned and configured to fit into load bearing plate mounting aperture 62 for each of outer portions 46. A pair of longitudinal grooves 66, formed in the side walls of load bearing plate 64, receive projections 68 formed in the periphery of load bearing plate mounting aperture 62 to secure load bearing plate 64 within load bearing plate mounting aperture 62. Load bearing plate 64, preferably, includes at least one longitudinal track 70 formed in an inner surface thereof. Track 70 serves as an upper surface of load bearing portion 56 of ball track 54. A plurality of bearing balls 72 are positioned in ball track 54 and, when in load bearing portion 56, transmit loads from load bearing plates 64 to linear shaft 99, as well as facilitating reciprocal longitudinal motion therealong. An inner surface 74 of inner portions 42 define a longitudinal opening 76 that allow bearing balls 72 to contact shaft 99.

As shown in FIGS. 1 and 2, outer portions 46 include retainer receiving grooves 78 defined within an outer surface 80 of each of outer portions 46. Retainer receiving grooves 78 are configured to receive a retainer 82 to maintain linear motion bearing assembly 20 in an assembled configuration about linear shaft 99. Each of outer portions 46 include a pair of retainer receiving grooves 78 oriented in a substantially parallel alignment with corresponding retainer receiving grooves 78 of adjoining outer portions 46. It is contemplated that each of outer portions 46 may have a single retainer receiving groove or multiple grooves. It is further contemplated that the grooves may be oriented in other configurations such as transverse or diagonal.

Linear motion bearing assembly 20, in accordance with the embodiment shown in FIGS. 1 and 2, is efficiently and easily assembled using a novel process. Continuous strip 40 is rolled in a continuous polar direction, shown by arrow A (FIG. 2), about linear shaft 99. Bearing balls 72 are positioned within ball track 54 of a first inner portion 41 of continuous strip 40. Load bearing plate 64 is positioned within load bearing plate mounting aperture 62 of a first outer portion 45 so that groove 66, engages projections 68 to maintain load bearing plate 64 within load bearing plate mounting aperture 62.

Continuous strip 44 is rolled thereabout continuous strip 40 and linear shaft 99 in the same continuous polar direction (arrow A) to complete a monolithic structure so that first outer portion 45 engages and overlays onto first inner portion 41 to form a ball retainer segment 32 of monolithic ball retainer 30 of linear motion bearing assembly 20. The next inner portion 42 and outer portion 46 located adjacent to first inner portion 41 and first outer portion 45, respectively, are assembled similar

to first inner portion 41 and first outer portion 45, discussed above, forming a next adjacent ball retainer segment 32 of ball retainer 30. The next adjacent inner portion 42 and outer portion 46 are subsequently assembled until continuous strip 40 and continuous strip 44 are properly aligned to form ball retainer segments 32 of ball retainer 30 about linear shaft 99.

Ball retainer 30 is supported and continuous strip 40 and continuous trip 44 are maintained in cooperative engagement by retainers 82. Other retaining mechanisms are contemplated for maintaining linear motion bearing assembly 20 in an assembled orientation such as clips, sleeves, sheaths, etc. fabricated from metal or polymers. Retainer 82 may be positioned in contacting engagement about continuous strip 44 within retainer receiving grooves 78 of outer portions 46, in a wrap-around type orientation, to maintain ball retainer 30 in a desired orientation about linear shaft 99.

As discussed hereinabove, ball retainer 30 is assembled from a monolithically formed continuous strip 40 of inner portions 42 having an end monolithically formed wifh an end of a monolithically formed continuous strip 44 of outer portions 46 and is extremely cost efficient in that a typical two part bearing is monolithically formed, thereby decreasing the number of separate components. This configuration allows for the use of a two-part die to form the monolithic part. The two part dies offer a lower capital cost for bearing production and the present bearing subassembly configuration offers simple assembly and flexibility. These configurations can be for application with round shafts, profile rails, and radial bearings, etc.

Linear motion bearing assembly 20, in accordance with the embodiment shown in FIG. 2A, may alternatively be assembled using a novel process.

In FIG. 2A, inner portion end 51 of continuous strip 40 is connected to outer portion end 52 of continuous strip 44, as discussed above, to form ball retainer 30. Linear motion bearing assembly 20 is then assembled similar to the process described with regard to FIGS. 1 and 2.

FIGS. 3 and 4 illustrate another embodiment of a linear motion bearing subassembly having a monolithic ball retainer for use in a closed-type linear motion bearing assembly. Linear motion bearing assembly 120 has a linear motion bearing subassembly 122 including a monolithic ball retainer 130 having a monolithically formed continuous strip 140 of inner portions 142 and a monolithically formed continuous strip 144 of outer portions 146. As shown in FIG. 4, each inner portion 142 engages and overlays onto a corresponding outer portion 146 to form a self- contained ball retainer segment 132 of ball retainer 130. Ball retainer 130 may include a multiplicity of ball retainer segments 132 according to the number of corresponding inner and outer portions.

As shown in FIGS. 3 and 4, inner portions 142 are monolithically formed, forming the continuous strip 140, by living hinges 148 located between the individual inner portions 142. Outer portions 146 are monolithically formed, forming the continuous strip 144, by living hinges 150 located between the individual outer portions 146. Living hinges 148 and 150 define openings 149 therein, for increased flexibility of

continuous strip 140 and continuous strip 144, providing for facile assembly of ball retainer 130. Ball retainer 130 may be used in applications such as, for example, round shafts, profiled rails and radial bearing, etc.

An inner portion end 151 of continuous strip 140 is monolithically formed with an outer portion end 152 of continuous strip 144 by a living hinge 153 forming monolithic ball retainer 130. The monolithic formation of continuous strip 140 and continuous strip 144 facilitate assembly of monolithic ball retainer 130.

Living hinge 153 is a flexible member monolithically formed as part of monolithic ball retainer 130. It is contemplated that continuous strip 140 and continuous strip 144 may be separately attachable, similar to FIG. 2A.

As shown in FIGS. 3 and 4, each of inner portions 142 define a ball track 154 therein. Ball track 154 includes a load bearing portion 156 and a return portion 158 interconnected by turnarounds 160. Each of outer portions 146 are configured to engage and overlay onto corresponding inner portions 142 to form ball retainer segment 132 (FIG. 4) and include a load bearing plate mounting aperture 162.

Inner portions 142 and outer portions 146 engage through flush contact between an outer surface 143 of each of inner portions 142 and an inner surface 147 of each of corresponding outer portions 146.

As shown in FIG. 4, a load bearing plate 164 is dimensioned and configured to fit into load bearing plate mounting aperture 162 for each of outer portions 146. A pair of longitudinal grooves 166, formed in the side walls of load bearing plate 164, receive projections 168 formed in the periphery of load bearing plate mounting aperture 162 to secure load bearing plate 164 within load bearing plate mounting aperture 162. Load bearing plate 164, preferably, includes at least one

longitudinal track 170 formed in an inner surface thereof. Track 170 serves as an upper surface of load bearing portion 156 of ball track 154. A plurality of bearing balls 172 are positioned in ball track 154 and, when in load bearing portion 156, transmit loads from load bearing plates 164 to, for example, a linear shaft as well as facilitating reciprocal longitudinal motion therealong. Inner surface 174 of inner portions 142 defines an opening or the like to allow bearing balls 172 to contact the shaft.

Outer portions 146 include retainer receiving grooves 178 defined within an outer surface 180 of each of outer portions 146. Retainer receiving grooves 178 are configured to receive a retainer or the like, similar to the retaining elements illustrated in FIGS. 1 and 2, to maintain linear motion bearing assembly 120 in an assembled configuration. Each of outer portions 146 include a pair of retainer receiving grooves 178 oriented in a substantially parallel alignment with corresponding retainer receiving grooves 178 of adjoining outer portions 146.

Linear motion bearing assembly 120, in accordance with the embodiments shown in FIGS. 3 and 4, is efficiently and easily assembled using a novel process. Continuous strip 140 is rolled in a continuous polar direction, shown by arrow B (FIG. 4), about a linear shaft or the like, similar to the assembly process illustrated in FIGS. 1 and 2. Bearing balls 172 are positioned within ball track 154 of a first inner portion 141 of continuous strip 140. Load bearing plate 164 is positioned within load bearing plate mounting aperture 162 of a first outer portion 145 so that groove 166, engages projections 168 to maintain load bearing plate 164 within load bearing plate mounting aperture 162.

Continuous strip 144 is rolled thereabout continuous strip 140 and a

linear shaft in a reverse continuous polar direction (arrow C) to complete a monolithic structure so that first outer portion 145 engages and overlays onto first inner portion 141 to form a ball retainer segment 132 of monolithic ball retainer 130 of linear motion bearing assembly 120. The next inner portion 142 and outer portion 146 located adjacent to first inner portion 141 and first inner portion 145, respectively, are assembled similar to first inner portion 141 and first outer portion 145, discussed above, forming a ball retainer segment of ball retainer 130. The next adjacent inner portion 142 and outer portion 146 are subsequently assembled until continuous strip 140 and continuous strip 144 are properly aligned to form ball retainer segments 132 of ball retainer 130.

Ball retainer 130 is supported and continuous strip 140 and continuous strip 144 may be maintained in cooperative engagement by a retainer or the like, similar to those components discussed above with regard to FIGS. 1 and 2.

FIGS. 5 and 6 illustrate another alternate embodiment of a linear motion bearing subassembly having a ball retainer for use in open or closed-type linear motion bearing assemblies. Ball retainer 230 is formed of a plurality of self- contained interengageable ball retainer segments 232. It is contemplated that ball retainer segments 232 may have various configurations such as, for example, arcuate, planar, angular, parabolic, etc. Ball retainer segment 232 includes an inner portion 242 and an outer portion 246. Although a single inner portion and a single outer portion are shown, it is envisioned that each ball retainer segment may include multiple inner portions and outer portions.

An inner portion end 251 of inner portion 242 is monolithically formed with an outer portion end 252 of outer portion 246 by a continuous living hinge 253

forming monolithic ball retainer segment 232. It is contemplated that living hinge 253 may include openings therein or an intermittent formation for increased flexibility of inner portion 240 and outer portion 244, providing facile assembly of ball retainer segment 232. The monolithic formation of inner portion 242 and outer portion 246 facilitate assembly of ball retainer segment 232. Living hinge 253 is a flexible connecting member monolithically formed as part of ball retainer segment 232. It is contemplated that inner portion 242 and outer portion 246 may be separately attached components of ball retainer segment 232, similar to FIG. 2A. It is also contemplated that inner portion 242 and outer portion 246 may be removably attachable components of ball retainer segment 232.

As shown in FIG. 5, inner portion 242 defines a ball track 254 therein.

Ball track 254 includes a load bearing portion 256 and a return portion 258 interconnected by turnarounds 260. Outer portion 246 is configured to engage and overlay onto corresponding inner portion 242 and includes a load bearing plate mounting aperture 262. Inner portion 242 and outer portion 246 engage through flush contact between an outer surface 243 of inner portion 242 and an inner surface 247 of outer portion 246. Inner portion 242 is maintained in flush contact with outer portion 246 in an interlocked relationship. Outer portion 246 includes interlocking mechanism keys 290 and inner portion 242 includes interlocking key ways 291.

Interlocking mechanism keys 290 interengage interlocking key ways 291 to form self contained ball retainer segments 232. Alternate engagement mechanisms are contemplated to enhance the cooperative engagement and overlay of inner portion 242 and outer portion 246 such as, for example, snap fit, pins, grooves, adhesives, etc. and are within the scope of knowledge of one skilled in the art.

As shown in FIG. 6, a load bearing plate 264 is dimensioned and configured to fit into load bearing plate mounting aperture 262 of outer portion 246.

It is contemplated that load bearing plate 264 may be self aligning or not self aligning.

A pair of longitudinal grooves 266, formed in the side walls of load bearing plate 264, receive projections 268 formed in the periphery of load bearing plate mounting aperture 262 to secure load bearing plate 264 within load bearing plate mounting aperture 262. Load bearing plate 264, preferably, includes at least one longitudinal track 270 formed in an inner surface thereof. Track 270 serves as an upper surface of load bearing portion 256 of ball track 254.

A plurality of bearing balls 272, shown in FIGS. 5 and 6, are positioned in ball track 254 and, when in load bearing portion 256, transmit loads from load bearing plates 264 to, for example, a linear shaft, as well as facilitating reciprocal longitudinal motion therealong. An inner surface 274 of inner portion 242 defines an opening or the like to allow bearing balls 272 to contact the shaft.

A linear motion bearing subassembly 222 for use with a linear motion bearing assembly, in accordance with the embodiment shown in FIGS. 5 and 6, is efficiently and easily assembled using a novel process. Bearing balls 272 are positioned within ball track 254 of inner portion 242. Load bearing plate 264 is positioned within load bearing plate mounting aperture 262 of outer portion 246 so that groove 266, engages projections 268 to maintain load bearing plate 264 within load bearing plate mounting aperture 262.

Outer portion 246 is manipulated in a continuous polar direction, shown by arrow D in FIG. 6, to complete a monolithic structure so that outer portion 246 engages and overlays onto inner portion 242 to form ball retainer segment 232.

Interlocking mechanism keys 290 interengage interlocking key ways 291 to form ball retainer segment 232. A plurality of ball retainer segments 232 may be positioned about a linear shaft (not shown) and are secured together forming ball retainer 230 of linear motion bearing subassembly 222. Linear motion bearing subassembly 222 is fabricated from multiple interengagable self-contained ball retainer segments 232 depending on the bearing application, i. e., linear shafts, profile rails, radial bearings, etc. and open or closed bearings. One skilled in the art will readily appreciate that the linear motion bearing subassembly could be fabricated from two or more self- contained segments simply by configuring and dimensioning the orientation and size of the segments.

FIGS. 7 and 8 illustrate linear motion bearing assemblies using self- contained interengagable ball retainer segments, similar to those described in FIGS. 5 and 6. As shown in FIG. 7, a linear motion bearing assembly 320 having a linear motion bearing subassembly 322 including ball retainer 330 for use in a closed type linear motion bearing assembly. Ball retainer 330 is formed of self-contained interengagable ball retainer segments 332, similar to ball retainer segments 232 described with regard to

the embodiment shown in FIGS. 5 and 6. As shown in FIG. 7, linear motion bearing subassembly 322 is fabricated from interengageable self-contained ball retainer segments 332 which are supported in interengagable association by retainer elements 382.

Similar to FIGS. 5 and 6, each ball retainer segment 332 in FIG. 7 includes an inner portion 342 and an outer portion 346. An inner portion end 351 is monolithically formed with an outer portion end 352 by a living hinge 353 forming ball retainer segment 332. Inner portion 342 defines a ball track (not shown), similar to ball track 254. Outer portion 346 is configured to engage and overlay onto corresponding inner portion 342 and include a load bearing plate mounting aperture 362.

A load bearing plate 364 is dimensioned and configured to fit into load bearing plate mounting aperture 362 of outer portion 346. A plurality of bearing balls 372 are positioned in ball track 354 and, when in load bearing track 354, transmits loads from load bearing plates 364, as well as facilitating reciprocal longitudinal motion therealong. An inner surface 374 of inner portion 342 defines a longitudinal opening 376 that allows bearing balls 372 to contact a linear shaft.

Each of ball retainer segments 332 in FIG. 7 are efficiently and easily assembled using the novel process described with regard to FIGS. 5 and 6. In FIG. 7, interengagable self-contained ball retainer segments 332 are assembled adjacent one another about a linear shaft 699 (shown in FIG. 12). In FIG. 7, each outer portion 346 includes retainer receiving grooves 378 defined within an outer surface 380 of each outer portion 346. Retainer receiving grooves 378 are configured to receive retainer 382 to maintain linear motion bearing assembly 320 in an assembled configuration

about a linear shaft or the like. Each of outer portions 346 include a pair of retainer receiving grooves 378 oriented in a substantially parallel alignment with corresponding retainer receiving grooves 378 of adjacent outer portions 346. It is contemplated that each of outer portion 346 may have a single retainer receiving groove or multiple grooves.

FIG. 8 illustrates an alternate embodiment of a linear motion bearing subassembly having a ball retainer for use with a closed-type linear motion bearing assembly, similar to that described in FIG. 7.

Ball retainer 430 is substantially rectangular and is formed of self- contained interengagable ball retainer segments 432 that are substantially planar. Ball retainer segment 432 includes an inner portion 442 and an outer portion 446.

An inner portion end 451 of inner portion 442 is monolithically formed with an outer portion end 452 of outer portion 446 by a continuous living hinge 453 forming monolithic ball retainer segment 432. It is contemplated that living hinge 453 may include openings therein or an intermittent formation for increased flexibility of inner portion 442 and outer portion 446, providing facile assembly of ball retainer segment 432. The formation of inner portion 442 and outer portion 446 facilitate assembly of ball retainer 430. Living hinge 453 is a flexible member monolithically formed as part of ball retainer segment 432. It is contemplated that inner portion 442 and outer portion 446 may be separately attached components of ball retainer segment 432. It is also contemplated that inner portion 442 and outer portion 44 may be removably attachable components of ball retainer segments 432.

Each of inner portions 442 defines a ball track 454 therein. Ball track 454 includes a load bearing portion 456 and a return portion 458 interconnected by turnarounds 460. Each of outer portions 446 are configured to engage and overlay onto a corresponding inner portion 442 and includes a load bearing plate mounting aperture 462. Inner portion 442 and outer portion 446 engage through flush contact between an outer surface 443 of inner portion 442 and an inner surface 447 of outer portion 446. Inner portion 442 is maintained in flush contact with outer portion 446 in an interlocked relationship. Outer portion 446 includes interlocking mechanism keys 490 and inner portion 442 includes interlocking key ways 491. Interlocking mechanism keys 490 interengage interlock key ways 491 to form self contained ball retainer segments 432. Alternate engagement mechanisms are contemplated to enhance the cooperative engagement and overlay of inner portion 442 and outer portion 446 such as, for example, snap fit, pins, grooves, adhesives, etc. and are within the scope of knowledge of one skilled in this art.

Similar to FIG. 6, FIG. 8 shows a load bearing plate 464 dimensioned and configured to fit into load bearing plate mounting aperture 462 of outer portion 446. It is contemplated that load bearing plate 464 may be self aligning or not self aligning. A pair of longitudinal grooves may be formed in the side walls of load bearing plate 464, receiving projections 468 formed in the periphery of load bearing plate mounting aperture 462 to secure load bearing plate 464 within load bearing plate mounting aperture 462.

Load bearing plate 464, preferably, includes at least one longitudinal track formed in an inner surface thereof The track serves as an upper surface of load bearing portion 456. ouf ball track 454.

A plurality of bearing balls 472 are positioned in ball track 454 and, when in load bearing portion 456, transmit loads from load bearing plates 464 to, for example, a linear shaft, as well as facilitating reciprocal longitudinal motion therealong. An inner surface 474 of inner portion 442 defines a longitudinal opening 476 to allow bearing balls 472 to contact the shaft.

A linear motion bearing subassembly 422, in accordance with the embodiment shown in FIG. 8, is efficiently and easily assembled using a novel process. Bearing balls 472 are positioned within ball track 454 of inner portion 442.

Load bearing plate 464 is positioned within load bearing plate mounting aperture 462 of outer portion 446 so that a groove may engage projection 468 to maintain load bearing plate 464 within load bearing plate mounting aperture 462.

Outer portion 446 is manipulated in a continuous polar direction, shown by arrow E in FIG.'8 to complete a monolithic structure so that outer portion 446 engages and overlays onto inner portion 442 to form ball retainer segment 432 of ball retainer 430 of linear motion bearing subassembly 422. Interlocking mechanism keys 490 interengage interlocking key ways 491 to form ball retainer segment 432.

Linear motion bearing subassembly 422 may be fabricated from multiple planar interengagable self-contained ball retainer segments 432 depending on the bearing application, i. e., linear shafts, profiled rails, etc. and open or closed bearings. One skilled in the art will readily appreciate that the linear motion bearing assembly could be fabricated from two or more self-contained segments simply by configuring and

dimensioning the length and size of the segments. Ball retainer 430 is assembled in a substantially rectangular configuration for use in a closed type linear motion bearing assembly 420.

FIGS. 9-11 illustrate alternate embodiments of a monolithic ball retainer segment 532 for use in open or closed type linear motion bearing assemblies.

FIG. 9 shows a self-contained interengageable ball retainer segment 532 including inner portion 542 and an outer portion 546.

An inner portion end 551 of inner portion 542 is monolithically formed with an outer portion end 552 of outer portion 54 by a living hinge membrane 553 forming ball retainer segment 532. The formation of inner portion 542 and outer portion 546 facilitate assembly of ball retainer segment 532. Living hinge membrane 553 is a flexible member monolithically formed as a part of ball retainer segment 532.

Living hinge membrane 553 provides increased clearance for molding purposes providing a facile drawing process in manufacture of the monolithic part which includes inner portion 542 and outer portion 546. This increased clearance is provided by a side surface 590 of outer portion 546 which contacts a hinge surface 591 of living hinge membrane 553 in an abutting relationship providing an alternate hinging configuration. It is contemplated that living hinge membrane 553 may have openings or the like for increased flexibility of ball retainer segment 532 during assembly.

Inner portion 542 includes a ball track 554, similar to those discussed above. Outer portion 546 is configured to engage and overlay onto corresponding inner portion 542 and includes a load bearing plate mounting aperture 562 having projections 568 formed in a periphery thereof to secure a load bearing plate (not shown), discussed above.

As shown in FIG. 10, an alternate embodiment of ball retainer segment 532 includes a living hinge membrane 653 having an intermittent configuration providing increased flexibility for ball retainer segment 532.

FIG. 11 is a cross-sectional view of the embodiment shown in FIG. 9 illustrating the abutting relationship provided by living hinge membrane 553, discussed above. Living hinge membrane 553 also provides flush contact with inner portion end 551 and outer portion end 552, so that upon assembly of ball retainer segment 532, living hinge membrane 553 does not project outward. This provides a uniform fit with adjacent ball retainer segments 532. Ball retainer segment 532 is fabricated from a polymer. It is contemplated that ball retainer segment 532 may also be fabricated from metalsSrubber, etc.

A ball retainer 530 including ball retainer segments 532, in accordance with the embodiment shown in FIGS. 9-11, is efficiently and easily assembled using the novel process described with regard to FIGS. 5 and 6.

Referring now to FIG. 12, a closed-type linear motion bearing assembly 320 is illustrated including a linear motion bearing subassembly 322 having ball retainer 330 shown in FIG. 8, for use with a linear shaft 699. Linear motion bearing subassembly 322 is installed about linear shaft 699. Assembly 320 includes end caps 700 positioned on each longitudinal end of assembled ball retainer 330, to

maintain ball retainer 330 in an assembled condition and support the structure as it moves. Moreover, subassembly 322 includes a retainer sleeve 702 to enclose and maintain assembled ball retainer 330. Retaining sleeve 702 also prevents exposure of the components of linear motion bearing subassembly 322 to ambient conditions and contaminants such as dirt and dust that could deleteriously affect the operation and life of subassembly 322, as well as support the structure as it moves. It is contemplated that end caps 700 and retaining sleeve 702 may be fabricated from a wide variety of engineering plastics, polymers, rubbers, and metal depending upon the applications of and demands on the bearing assembly.

Referring now to FIG. 13, an open-type a linear motion bearing assembly 820 is illustrated including a linear motion bearing subassembly 822 having interengageable self-contained ball retainer segments 232, shown and described, including their assembly, in FIGS. 5 and 6, for use with a linear shaft 799. In FIG. 13, ball retainer segments 232 are shown with outer portion 246 having retainer receiving grooves 878 defined within an outer surface 880 thereof. Retainer receiving grooves 878 are configured to receive an open bearing retainer 882 to maintain a ball retainer 830 in an assembled configuration. Assembly 822 includes open-type end caps 884 positioned on each longitudinal end of assembled ball retainer 830 to further maintain ball retainer 830 in an assembled condition and support the structure as it moves.

Moreover, subassembly 822 includes open-type retaining sleeve 886 to enclose and maintain assembled ball retainer 830 and support the structure as it moves.

Once the ball retainer segments are complete, the segments are assembled adjacent one another to form a complete ball retainer. Retainer rings may be positioned around the segments to assist in holding the segments in a desired

orientation. This self-contained segment is extremely cost efficient and totally eliminates the need for separate outer housing structure to enclose the bearing elements.

To the extent not already indicated, it will also be understood by those of ordinary skill in the art that any one of the various specific embodiments herein described and illustrated may be further modified to incorporate features in the other specific embodiments.

The invention in its broader aspects therefore is not limited to the specific embodiments herein shown and described but departures may be made therefrom within the scope of the accompanying claims without departing from the principles of the invention and without sacrificing its chief advantages.