Roller Tensioning Assembly

The present disclosure relates generally to roller assemblies for linear rail systems, and in particular for use in robotic automation equipment.

In typical robotic automation equipment, linear rail systems are commonly used to move objects smoothly in a controlled and precise manner. Conventional linear rail systems include a carriage having pairs of opposing rollers which bracket a rail, and the carriage is configured to move along a longitudinal axis of the rail. Control of the contact force between the rollers and the rail is crucial for smooth operation. If the required contact force is not maintained uniformly and constantly throughout travel, the result may include vibrations, loss of precision, and ultimately failure of the system. It is therefore desirable for the contact force to be maintained uniformly irrespective of dynamic forces acting on the system and any surface irregularities.

Hence, a tensioning mechanism is advantageous to apply a constant force between the rollers and track. Conventional tensioning mechanisms involve certain shortcomings and disadvantages, however, and there thus remains an ongoing need for improved tensioning mechanisms for providing a constant force against the changing dynamic forces such that the roller position remains constant throughout travel.

Throughout the drawings, sometimes only one or fewer than all of the instances of an element visible in the view are designated by a lead line and reference character, for the sake only of simplicity and to avoid obfuscation. It will be understood, however, that in such cases, in accordance with the corresponding description, that all other instances are likewise designated and encompassed by the corresponding description.

In the drawings and this description, the use of a brace (‘{’ or ‘}’) between reference characters designates a genus and species relationship, such that “X {Y” indicates that ‘X’ is a species of a broader genus ‘Y’. A numerical reference character suffixed by a letter (e.g. “A”, “B”) designates a separate instance of the element designated by the numerical reference character (e.g. “A”, “B” are each separate instances of the element designated by “”).

The systems, devices, and methods disclosed herein may address at least some of the shortcomings or disadvantages of previous solutions, and may provide yet further benefits or advantages, with respect to the adjustment and use of roller assemblies for linear rail systems.

A linear rail systemis shown in. The linear rail systemincludes a railand a carriage. The railhas a first endand a second endopposite the first endalong a longitudinal axis L of the linear rail system. The linear rail systemfurther has a transverse axis T perpendicular to the longitudinal axis L, and a normal axis N perpendicular to both the longitudinal axis L and the transverse axis T.

The carriageis shown in isolation in, and has a platform, at least one fixed roller assembly(fixed roller assembliesA,B shown, each being an instance of fixed roller assembly), and at least one adjustable roller assembly(adjustable roller assembliesA,B shown, each being an instance of adjustable roller assembly). For each adjustable roller assembly, the platformhas a corresponding bushing borepassing through the platform, and through which the adjustable roller assemblypasses. The platformis planar, in the plane P, which corresponds to the plane of the drawings page containing, although other embodiments having a platformof other shapes are possible and contemplated.

The platformhas a roller side, and an adjustment sideopposite the roller sidealong the normal axis N—that is, on opposite sides of plane P. Each fixed roller assemblycomprises a fixed roller(fixed rollersA,B shown, each being an instance of fixed roller) rollably mounted at the roller sideof the platform. Each adjustable roller assemblycomprises an adjustable roller(adjustable rollersA,B shown, each being an instance of adjustable roller) rollably mounted at the roller sideof the platform. Each adjustable roller assemblyhas a central axis C and an adjustable rolling axis R extending along the normal axis N. Similarly, each fixed rollerhas a fixed rolling axis F extending along the normal axis N.

The carriageis rollably mountable to the rail, with the fixed rollerof each fixed roller assemblyand the adjustable rollerof each adjustable roller assemblyin contact with the rail, wherein at least some of the fixed rollersand the adjustable rollersare on transversely opposite sides of the railso as to bracket and hug the rail. In this way, the carriageis mounted to the railand can travel along the longitudinal axis L of the rail. As described below, the adjustable roller assembliesare operable to vary alignment between the adjustable rolling axis R and the central axis C of the respective adjustable rollersthereof, to thereby adjust relative spacing between the fixed rolling axis F of at least some of the fixed rollersand the adjustable rolling axis R of at least some of the adjustable rollers, thereby to adjust contact forces between the railand at least some of the fixed rollersand/or the adjustable rollers—that is, to adjust a degree of squeezing force applied to the rail.

The carriagemay have any number of fixed roller assembliesand adjustable roller assemblies. In different embodiments, one or more fixed roller assembliesare paired with one or more transversely opposing adjustable roller assembliessuch that the fixed roller assembliesare longitudinally aligned on one transverse side of the platform, and the adjustable roller assembliesare longitudinally aligned on an opposite transverse side of the platform. In some embodiments there are at least two pairs of the fixed roller assembliesand the adjustable roller assemblies, as shown in the drawings, although other embodiments with any numbers or pairs of the fixed roller assembliesand the adjustable roller assembliesare possible and contemplated. Furthermore, other embodiments having the fixed roller assembliesand the adjustable roller assembliesin other configurations are possible and contemplated, for example, in a staggered configuration, wherein at least some fixed roller assembliesare longitudinally aligned with at least some adjustable roller assemblies.

The adjustable roller assembliesare operable as a tensioning mechanism to adjust, set and hold the contact force between the fixed rollersand the adjustable rollersof the carriageon the rail. The adjustable roller assembliesmay provide a constant force against changing dynamic forces such that the fixed rollersand the adjustable rollersremain in constant uniform contact against the railthroughout travel of the carriage, or at least tend to do so. Such changing dynamic forces may include, without limitation, varying forces based on the weight of the object being moved by the linear rail systemand the accelerating forces applied to the object.

An embodiment of the carriagecomprising the adjustable roller assemblyare shown in, withshowing exploded views of the adjustable roller assembly. The adjustable roller assemblyhas an indexing collar, an eccentric bushing, an adjustable roller, a suspension element, and an adjustment collar. In different embodiments, the adjustable roller assemblyalso has one or more of an adjustable roller threaded fastener, at least one indexing pin, at least one suspension element threaded fastener, a washer, at least one screw, and a roller axle.

As described and shown in further detail below, and with reference to, in operation of the adjustable roller assembly, the adjustment collaris turnable to adjust a relative rotational position of (that is, to turn) the eccentric bushingabout the central axis C thereby to adjust a relative transverse spacing S between the adjustable rolling axis R of the corresponding adjustable rollerand a fixed rolling axis F of a paired fixed roller. The at least one indexing pinis operable to couple the indexing collar, which is fixed to the platform, to the adjustment collar, thereby to fix a rotational position thereof, and therefore likewise to set a rotational position of the eccentric bushing. The eccentric bushingis coupled to the adjustment collarvia the suspension element, which is at least somewhat elastic, thereby permitting at least some variability in the rotational position of the eccentric bushing—and therefore variability in the relative transverse spacing S—while urging the rotational position of the eccentric bushingback to the setpoint of the adjustment collar.

As shown in, the eccentric bushinghas an adjustment side endand a roller side endopposite the adjustment side end. The adjustable roller assemblyfurther has a tapped roller side fastener borealigned with the rolling axis R, and therefore transversely displaced, or off-center, from a central axis C of the eccentric bushingby an offset O. As shown particularly in, the adjustable rolleris mounted to the eccentric bushingby passing the threaded fastenerthrough the hubof the adjustable roller—which may include through the roller axleof the adjustable roller—and into the tapped roller side fastener bore. The threaded fastenermay be screwed into the fastener boreto rollably couple the adjustable rollerto the eccentric bushing. Other means and ways of rollably coupling the adjustable rollerto the eccentric bushingare possible and contemplated, so long as the rolling axis R of the adjustable rolleris off-center—that is, transversely displaced—from the central axis C of the eccentric bushing.

As shown particularly in, the eccentric bushingis coupled to the suspension elementby passing the adjustment side endof the eccentric bushingthrough the bushing boreof the platformand the indexing collar. In particular, and with reference to, the indexing collardefines a cylindrical channelsized and shaped to slidingly and fittingly receive the adjustment side endof the eccentric bushingthereby exposing the adjustment side endof the eccentric bushingon the adjustment sideof the platform. In particular, washermay be provided on the adjustment sideof the platform, aligned and nested with the adjustment side endof the eccentric bushingexposed on the adjustment sideof the platform, and coupled with the eccentric bushingby the at least one screwscrewed into corresponding tapped retaining boresin the adjustment side endof the eccentric bushing(shown in), in order thereby to retain the eccentric bushingin the bushing boreof the platformand the cylindrical channelof the indexing collar.

The suspension elementis coupled with the eccentric bushing. In particular, and as shown in, the suspension elementis cylindrical, with a circular cross-section, although other embodiments with other shapes are possible and contemplated. The suspension elementcomprises an inner coreand an outer sleevethat is torsionally elastically coupled to the inner core. The suspension elementalso has at least one suspension element fastener boreprovided in the inner core. The suspension elementis coupled with the eccentric bushingby aligning the at least one suspension element fastener borewith corresponding tapped adjustment side fastener boresformed in the adjustment side endof the eccentric bushing(shown in), and in each instance a fasteneris passed through both to screw the suspension elementto the eccentric bushing. Other means and methods for rotationally coupling the suspension elementto the eccentric bushingare possible and contemplated. The suspension elementmay be made of any suitable material having a predetermined degree of rigidity and/or elasticity sufficient to allow for torsional elastic compression with reliable rebound. Such materials may include rubber. One well-known embodiment of the suspension elementis the DK-A™ rubber suspension element (Part number DK-A18X30) from ROSTA, which is available at: https://web.archive.org/web/20240221205201/https://www.rosta.com/en/suspension-2/.

As shown in, the adjustment collaris rotationally coupled with the suspension element. As shown particularly in, the adjustment collarmay be annular in shape. The adjustment collarhas a circumferential flangehaving an indexing structure, which as shown includes a plurality of indexing slotscircumferentially-spaced around the circumferential flange, although other indexing structures are possible and contemplated. Further, the adjustment collarforms a cylindrical channelwith an inner surface. The adjustment collarhas a mating structure, which is formed at the inner surfaceof the cylindrical channel. As shown, the mating structure may include at least one longitudinally extending spline. Turning to, the outer sleeveof the suspension elementhas a radially outer surface, including a mating structure which, as shown, may include at least one longitudinally extending grooves. The suspension elementand the adjustment collarare slidingly nested together using a spline-and-groove arrangement. More specifically, the adjustment collaris removably coupled with the suspension elementby slidingly mating the splinesof the adjustment collarwith the groovesof the suspension element—that is, by sliding the adjustment collarover the suspension elementwith the splinesand groovesaligned. In this way, the suspension elementis nested in axial alignment with the cylindrical channel, with the groovesand splinesmated, thereby rotationally fixing the adjustment collarand the suspension elementtogether.

As shown in, the indexing collarhas an annular faceon an adjustment side endof the indexing collar, and an indexing structure which, as shown, may include a plurality of indexing holesformed and circumferentially spaced in the annular face. Turning to, and with reference to, the indexing collarand the adjustment collarmay be rotationally coupled together using a pin, hole, and slot arrangement. Specifically, as described above, the indexing slotsof the adjustment collarare circumferentially spaced around the circumferential flangefor selective alignment with one of the indexing holesof the indexing collar. By turning the adjustment collarabout the central axis C, longitudinally aligning at least one of the indexing slotswith a paired indexing hole, and positioning, which may be by screwing, at least one of the indexing pinsthrough the indexing slotand into one of the corresponding indexing hole, the adjustment collarmay be rotationally coupled with the indexing collar.

When assembled as described above, the adjustable rollerof each adjustable roller assemblyis rollable about an adjustable rolling axis R transversely offset O from a central axis C of the adjustable roller assembly. The fixed rolleris rollable about the fixed rolling axis F of the corresponding fixed roller assembly. Each adjustable roller assemblyis operable as described to adjust the transverse spacing S (shown in) between the adjustable rolling axis R of its adjustable rollerand the fixed rolling axis F of the fixed rollerof a paired fixed roller assembly. As described, the suspension elementmay be made of any suitable material having a predetermined degree of rigidity and/or elasticity sufficient to allow for torsional compression with reliable rebound. As such, the adjustment collaris operable, as described, to set a rotational setpoint position of the eccentric bushingto provide a selected transverse spacing S between the adjustable rolling axis R of the corresponding adjustable rollerand the fixed rolling axis F of a paired fixed roller, with a preconfigured degree of surface force between the adjustable rollerand the fixed roller, on the one hand, and respective surfaces of the rail, on the other hand—that is, a preconfigured squeezing force or a degree of squeezing of the rail—due to the torsional compressibility of the suspension element. As described, the adjustment collarmay be secured in rotational position by the use of indexing pinsrotationally coupling the adjustment collarwith the indexing holesof the indexing collar, which is fixed to the platform. Such surface or squeezing forces are variable, however, given the torsionally elasticity of the suspension element, which is thus responsive to variation in the contact forces between the adjustable rollersand the fixed rollers, on the one hand, and the rail, on the other hand, as the carriagetravels along the railin use.

The embodiments of the carriage, and particularly the adjustable roller assemblydisclosed herein may provide numerous advantages over conventional mechanisms. Use of some embodiments may improve operations such as robotic automation. Some embodiments may provide superior uniform stability to the linear rail system, which can be achieved by simple and quick adjustments that can easily be made to the adjustable roller assemblywhich remains readily accessible on the carriage.

The embodiments of the adjustable roller assemblyand its parts described herein may be formed by any suitable manufacturing techniques and methods, and may be comprised of any suitable materials which will provide the required weight, strength, elasticity, hardness and wear resistance for use with for the linear rail system.

The adjustable roller assemblyas a kit in order to retrofit an existing linear rail system carriage, or in order to assembly a new one. The kit for the adjustable roller assemblycomprises substantially the same parts of the adjustable roller assemblydescribed herein. In particular, the kit comprises the indexing collar, the eccentric bushing, the suspension element, and the adjustment collar. In some embodiments, the kit also includes the indexing pins, the suspension element threaded fasteners, the washer, and the bolts. In some embodiments, the kit further comprises assembly instructions.

The following are non-limiting embodiments of the subject-matter disclosed herein.

Embodiment 1. An adjustable roller assembly for a linear rail system carriage, the adjustable roller assembly having an axis and comprising: as indexing collar having a first indexing structure; an eccentric bushing having an adjustment side end and a roller side end opposite the adjustment side end; an adjustable roller rollably mounted to the roller side end of the eccentric bushing, wherein a rolling axis of the adjustable roller is offset from the axis of the adjustable roller assembly; a suspension element comprising an inner core and an outer sleeve torsionally elastically coupled to the inner core, wherein the inner core is fixedly mounted to the adjustment side end of the eccentric bushing with the suspension element in axial alignment with the eccentric bushing; and an adjustment collar having a circumferential flange having a second indexing structure, wherein the first indexing structure and the second indexing structure are coupled to rotationally couple the adjustment collar with the suspension element.

Embodiment 2. The adjustable roller assembly of Embodiment 1, wherein: the first indexing structure comprises a plurality of circularly-spaced indexing holes; and the second indexing structure comprises at least one indexing slot positioned for selective alignment with the indexing holes of the indexing collar.

Embodiment 3. The adjustable roller assembly of Embodiment 2, further comprising: at least one indexing pin, wherein each indexing pin is positioned in a corresponding indexing slot and a corresponding indexing hole to rotationally couple the adjustment collar with the indexing collar, thereby maintaining a rotational position of the eccentric bushing.

Embodiment 4. The adjustable roller assembly of Embodiment 3, wherein the at least one indexing pin is a threaded fastener, and each of the at least one indexing hole is a corresponding tapped hole.

Embodiment 5. The adjustable roller assembly of Embodiment 2, wherein: the indexing collar has an annular face and the plurality of indexing holes are formed and circumferentially spaced in the annular face; and the circumferential flange of the adjustment collar has a plurality of the indexing slots circumferentially-spaced for selective alignment with corresponding ones of the indexing holes of the indexing collar.

Embodiment 6. The adjustable roller assembly of Embodiment 1, wherein: the outer sleeve of the suspension element has a first mating structure; the adjustment collar has a second mating structure; and the adjustment collar is removably coupled with the suspension element by mating of the first mating structure and the second mating structure.

Embodiment 7. The adjustable roller assembly of Embodiment 6, wherein: the suspension element is cylindrical; the first mating structure is formed on a radially outer surface of the outer sleeve; the adjustment collar forms a cylindrical channel, and the second mating structure is formed at an inner surface of the cylindrical channel; and the suspension element is nested in axial alignment with the cylindrical channel, with the first mating structure and the second mating structure mated.

Embodiment 8. The adjustable roller assembly of Embodiment 6, wherein: the first mating structure and the second mating structure form a spline-and-groove arrangement.

Embodiment 9. The adjustable roller assembly of Embodiment 1, wherein: the eccentric bushing has at least one tapped adjustment side fastener bore formed in the adjustment side end; and the suspension element is mounted to the eccentric bushing by at least one suspension element threaded fastener mated with the one tapped adjustment side fastener bore.

Embodiment 10. The adjustable roller assembly of Embodiment 1, wherein: the eccentric bushing has a tapped roller side fastener bore formed in the roller side end; and the adjustable roller is mounted to the eccentric bushing by an adjustable roller threaded fastener mated with the tapped roller side fastener bore of the eccentric bushing.

Embodiment 11. The adjustable roller assembly of Embodiment 10, wherein: the tapped roller side fastener bore is axially aligned with the rolling axis of the adjustable roller offset from the axis of the adjustable roller assembly.

Embodiment 12. A carriage for a linear rail system, the carriage comprising: a platform having a roller side, an adjustment side opposite the roller side, and a bushing bore; a fixed roller assembly mounted to the platform, the fixed roller assembly comprising a fixed roller rollably mounted at the roller side of the platform; and the adjustable roller assembly of Embodiment 1 mounted to the platform, wherein: the indexing collar is fixed at the adjustment side of the platform in axial alignment with the bushing bore; the eccentric bushing is installed in the bushing bore; and the adjustable roller is rollably mounted to the roller side end of the eccentric bushing at the roller side of the platform.

Embodiment 13. The carriage of Embodiment 12, wherein: the adjustment collar is rotatable to adjust a spacing between a fixed rolling axis of the fixed roller and a rolling axis of the adjustable roller.

Embodiment 14. The carriage of Embodiment 13, wherein: the suspension element is operable to vary the spacing between the rolling axis of the fixed roller and the rolling axis of the adjustable roller within predetermined limits responsive to forces applied to at least one of the fixed roller and the adjustable roller.

Embodiment 15. The carriage of Embodiment 13 comprising multiple pairs of the fixed roller assembly and the adjustable roller assembly.

Embodiment 16. A kit for an adjustable roller assembly for a linear rail system carriage, the kit comprising: as indexing collar having a first indexing structure; an eccentric bushing having an adjustment side end and a roller side end opposite the adjustment side end; a suspension element comprising an inner core and an outer sleeve torsionally elastically coupled to the inner core, wherein the inner core is fixedly mountable to the adjustment side end of the eccentric bushing with the suspension element in axial alignment with the eccentric bushing; and an adjustment collar having a circumferential flange having a second indexing structure, wherein the first indexing structure and the second indexing structure are couplable to rotationally couple the adjustment collar with the suspension element.

Embodiment 17. The kit of Embodiment 16, further comprising: instructions for assembling the adjustable roller assembly.

So that the present disclosure may be more readily understood, certain terms are defined. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which embodiments of the invention pertain. While many methods and materials similar, modified, or equivalent to those described herein can be used in the practice of the embodiments of the present invention without undue experimentation, the preferred materials and methods are described herein.

All terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting in any manner or scope. For example, as used in this specification and the appended claims, the singular forms “a,” “an” and “the” can include plural referents unless the content clearly indicates otherwise.

Numeric ranges recited within the specification are inclusive of the numbers defining the range and include each integer within the defined range. Throughout this disclosure, various aspects of this invention are presented in a range format. It should be understood that the description in range format is merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of the invention. Accordingly, the description of a range should be considered to have specifically disclosed all the possible sub-ranges, fractions, and individual numerical values within that range. For example, description of a range such as from 1 to 6 should be considered to have specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as individual numbers within that range, for example, 1, 2, 3, 4, 5, and 6, and decimals and fractions, for example, 1.2, 3.8, 1½, and 4. This applies regardless of the breadth of the range.

The terms “about” or “approximately” as used herein refer to variation in the numerical quantity that can occur, for example, through typical measuring techniques and equipment, with respect to any quantifiable variable, including, but not limited to, mass, volume, time, distance, voltage, and current. Further, given solid and liquid handling procedures used in the real world, there is certain inadvertent error and variation that is likely through differences in the manufacture, source, or purity of the ingredients used to make the compositions or carry out the methods and the like. The terms “about” and “approximately” also encompass these variations. Expressions which combine the terms “about” or “approximately” with one or more bounds of a range refer to a union of the bound modified by the term “about” or “approximately” as described above, and the range having the unmodified bound. Thus, for example, the expression “at least about X” means the union of “at least X” and “about X”. Similarly, “at most about Y” means the union of “at most Y” and “about Y”.

The phrase “and/or,” as used herein in the specification and in the claims, should be understood to mean “either or both” of the elements so conjoined, i.e., elements that are conjunctively present in some cases and disjunctively present in other cases. Multiple elements listed with “and/or” should be construed in the same fashion, i.e., “one or more” of the elements so conjoined. Other elements may optionally be present other than the elements specifically identified by the “and/or” clause, whether related or unrelated to those elements specifically identified. Thus, as a non-limiting example, a reference to “A and/or B”, when used in conjunction with open-ended language such as “comprising” can refer, in one embodiment, to A only (optionally including elements other than B); in another embodiment, to B only (optionally including elements other than A); in yet another embodiment, to both A and B (optionally including other elements); etc.

As used herein in the specification and in the claims, “or” should be understood to have the same meaning as “and/or” as defined above. For example, when separating items in a list, “or” or “and/or” shall be interpreted as being inclusive, i.e., the inclusion of at least one, but also including more than one, of a number or list of elements, and, optionally, additional unlisted items. Only terms clearly indicated to the contrary, such as “only one of” or “exactly one of”, or when used in the claims, “consisting of” will refer to the inclusion of exactly one element of a number or list of elements. In general, the term “or” as used herein shall only be interpreted as indicating exclusive alternatives (i.e. “one or the other but not both”) when preceded by terms of exclusivity, such as “either”, “one of”, “only one of”, or “exactly one of”. “Consisting essentially of”, when used in the claims, shall have its ordinary meaning as used in the field of patent law.

Embodiments of the disclosed subject-matter are described herein using the auxiliary verb “may”. When used herein, unless required otherwise by the context of usage, the auxiliary verb “may” designates an embodiment of the disclosed subject-matter which possesses the addressed object without requiring necessarily that any other embodiment of the disclosed subject-matter possesses the addressed object. Thus, a statement such as “X may include Y” indicates that the disclosed subject-matter includes embodiments where X includes Y, without requiring that all disclosed embodiments include Y, and without excluding any other embodiments which do not include Y.

While the disclosed subject-matter may be embodied in many different forms, there are described in detail herein specific embodiments. The present disclosure is an exemplification of the principles of the disclosed subject-matter and is not intended to limit the disclosed subject-matter to the particular embodiments illustrated. Furthermore, the disclosed subject-matter encompasses any possible combination of some or all of the various embodiments mentioned herein. In addition the disclosed subject-matter encompasses any possible combination that also specifically excludes any one or some of the various embodiments mentioned herein.

In the preceding description, for purposes of explanation, numerous details are set forth in order to provide a thorough understanding of the embodiments. However, it will be apparent to one skilled in the art that these specific details are not required. In particular, it will be appreciated that the various additional features shown in the drawings are generally optional unless specifically identified herein as required. The above-described embodiments are intended to be examples only. Alterations, modifications and variations can be effected to the particular embodiments by those of skill in the art. The scope of the claims should not be limited by the particular embodiments set forth herein, but should be construed in a manner consistent with the specification as a whole.