ES2903422T3 - Belt termination and tension in pulley arrangement for a robotic arm - Google Patents

Abstract

A robotic surgical system comprising a pulley arrangement, the pulley arrangement comprising: a base pulley portion (1212, 1640) rotatable about an axis; an adjustable pulley portion (1214, 1650) coupled to the base pulley portion and movable in a first direction parallel to the axis; a first slider block (1660a) and a second slider block (1660b) each engaged with the adjustable pulley portion; and a drive member (1220, 1220', 1620, 1620') coupled to the first and second slider blocks (1660a, 1660b), wherein the first and second slider blocks (1660a, 1660b) are arranged in an arcuate space in the pulley portion (1214, 1650) and engaged with the adjustable pulley portion (1214, 1650), wherein the first and second slider blocks (1660a, 1660b) are configured to move circumferentially toward each other in response to compression of the adjustable pulley portion (1214, 1650) against the base pulley portion (1212, 1640), thereby applying tension to the drive member (1220, 1220', 1620, 1620').

Description

DESCRIPTION

Belt termination and tension in pulley arrangement for a robotic arm

TECHNICAL FIELD

[0001] This invention relates generally to the field of robotic arms, and more specifically to pulley arrangements for a robotic arm.

BACKGROUND

[0002] Robotic arms are used in a variety of applications, such as in manufacturing and surgical procedures. For example, robot-assisted minimally invasive surgery (MIS) involves techniques intended to reduce tissue damage during a surgical procedure. Robotic-assisted laparoscopic procedures, for example, typically involve creating a series of small incisions in the patient (eg, in the abdomen) and inserting one or more instruments (eg, one or more tools, at least one camera, etc.) through the incisions into the patient. Surgical procedures are then performed using the inserted tools controlled by one or more sets of robotic arms commanded by an operator, with the aid of visualization provided by the camera. Overall, MIS provides multiple benefits, such as less patient scarring, less patient pain, shorter recovery times, and lower medical treatment costs associated with patient recovery. In US 2004/0266574, a power transmission mechanism is described that includes a pair of driving pulleys and driven pulleys on which a flexible transmission element is wound. Document US2008087871A1 describes a pulley arrangement comprising a base pulley part, a cover pulley part and a driving element.

[0003] In some variations, at least a portion of a robotic arm may be driven by one or more pulley arrangements (eg, a pulley drive, such as one that includes pulleys and cables that wrap around the pulleys). However, one drawback of pulley arrangements is that they tend to fail and/or lose performance due to the cable becoming loose and/or breaking during the course of use. Furthermore, in some applications, it may be desirable for the pulley arrangements in a robotic arm to be relatively compact, but capable of withstanding large driving forces.

RESUME

[0004] The present invention is defined solely by the appended claims, in particular by the scope of the appended independent claim 1. References to "embodiments" throughout the description that do not fall within the scope of the appended claims they simply represent possible examples of execution and therefore do not form part of the present invention.

[0005] A pulley arrangement (eg, a pulley drive or other suitable pulley arrangement) includes a base pulley portion rotatable within a drive plane, an adjustable pulley portion coupled to the drive portion base pulley and rotatable with respect to the base pulley portion within the drive plane, and a drive member including a first end coupled to the adjustable pulley portion, wherein at least a portion of the drive member is capable of enclosing the least partially around the adjustable pulley portion.

[0006] The pulley arrangement may, in some variations, include at least one second pulley, in which the driving element wraps at least partially around the second pulley. The second pulley can, for example, be placed at a suitable distance from the base pulley portion. A second end of the drive member may be coupled to the second pulley. Additionally or alternatively, a second drive element may include one end coupled to the base pulley portion and another end coupled to the second pulley.

[0007] The pulley arrangement includes a first sliding block engaging with the adjustable pulley portion. The first slider block is configured to move in a second direction different from the first direction, in response to compression of the adjustable pulley portion against the base pulley portion. The pulley arrangement includes a drive member having a first end that is coupled to the first slider block, and at least a portion of the drive member may at least partially wrap around the first slider block and/or the adjustable pulley portion. In some variations, the pulley arrangement may include one or more additional pulleys, such as an idler pulley, in which at least one drive member at least partially wraps the idler pulley.

[0008] The adjustable pulley portion and/or the first slide block may include at least one inclined surface. For example, the inclined surface can include a helical surface. An inclined surface of the adjustable pulley portion may, for example, engage with the slider block. Additionally or alternatively, an inclined surface of the slider block may engage the adjustable pulley portion.

[0009] The pulley arrangement includes a second sliding block engaged with the adjustable pulley portion. A second end of the pusher element, or one end of a second pusher element, may be coupled to the second sliding block. The first and second slider blocks are configured to move circumferentially toward each other in response to compression of the adjustable pulley portion against the base pulley portion. Their movement may have approximately equal speeds in response to such compression (eg, to provide bilaterally symmetrical tension) or different speeds. The first and second slider blocks are disposed in an arcuate space defined at least in part by the adjustable pulley portion. In some variations, the first and/or second slider blocks may be configured to move in an arcuate path, a linear path, or other suitable path in response to compression of the adjustable pulley portion against the base pulley portion.

[0010] The adjustable pulley portion may include a single member or multiple members engaged with one or more slider blocks. For example, the adjustable pulley portion may include a first member engaged with the first slider block and a second member engaged with the second slider block such that the first and second members are movable parallel to the axis about which the pulley rotates. base pulley part. The axial position of the adjustable pulley part relative to the base pulley part may be locked (eg with one or more fasteners, such as one or more fasteners engaging the adjustable pulley part and the base pulley part). In some variations, the adjustable pulley portion may be adjacent to the base pulley portion, such as axially aligned. In some variations, the adjustable pulley may be disposed in a recess in the base pulley portion.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011]

FIGS. 1A and 1B are illustrative schematics of an exemplary variation of a robotic arm and an exemplary variation of a pitch assembly on a robotic arm, respectively. FIG. 1C and 1D are detailed perspective views of an exemplary variation of a pitch assembly with a pulley arrangement.

FIG. 2A is an illustrative schematic of an exemplary variation of a multilayer drive member in a pulley arrangement. FIG. 2B is a detailed view of a shear substrate in an exemplary variation of a driving member.

FIGS. 3A and 3B are a perspective view and exploded views, respectively, of an exemplary variation of a drive member coupled to a pulley.

FIGS. 4A-4D are detailed perspective, cross-sectional, side, and perspective views, respectively, of an exemplary variation of a drive member coupled to a pulley.

FIGS. 5A and 5B are perspective and side views, respectively, of an exemplary variation of a drive member coupled to a pulley.

FIGS. 6A-6D are perspective, cross-sectional, side, and detail views, respectively, of an exemplary variation of a drive member coupled to a pulley.

de una variación ejemplar de un elemento de arrastre adjunto a una polea. La FIG. 8 es una vista lateral

de una variación ejemplar de un elemento de arrastre adjunto a una polea. La FIG. 9 es una vista lateral

de una variación ejemplar de un elemento de arrastre adjunto a una polea. La FIG. 10A es una vista despiezada de una variación ejemplar de un elemento de arrastre adjunto a una polea.FIG. 7 is a side view

of an exemplary variation of a drive member attached to a pulley. FIG. 8 is a side view

of an exemplary variation of a drive member attached to a pulley. FIG. 9 is a side view

of an exemplary variation of a drive member attached to a pulley. FIG. 10A is an exploded view of an exemplary variation of a drive member attached to a pulley.

FIGS. 10B-10D are schematic illustrations of a method of assembling the pusher member fitting depicted in FIG. 10A.

FIG. 11 is a schematic illustration of an exemplary variation of a drive member welded to a pulley.

FIG. 12A is a perspective view of an exemplary variation of a pulley arrangement that allows a drive member to be tensioned. FIGS. 12B and 12C are a sectional perspective view and a side view, respectively, of an adjustment pulley for adjusting tension in the pulley arrangement shown in Fig.

FIG. 12A.

FIGS. 13A-13C are schematic illustrations of a method of adjusting tension in a drive member with the adjustment pulley shown in FIG. 12A.

FIG. 14A is a side view of an exemplary variation of a pulley arrangement that allows a drive member to be tensioned. FIG. 14B is a side view of an adjustment pulley in the pulley arrangement shown in FIG. 14 TO.

FIG. 15A and 15B are perspective and top views, respectively, of an exemplary variation of a pitch link assembly incorporating one or more pulley arrangements.

FIG. 16A is a perspective view of one embodiment of a pulley arrangement in accordance with the invention that allows a drive member to be tensioned. FIG. 16B is a side view with detailed inset views of an adjusting pulley and an idler pulley in the exemplary variation of a pulley arrangement depicted in FIG. 16A. FIG. 16C is an exploded view of an exemplary slack pulley. FIG. 16D is an exploded view of an exemplary idler pulley. FIGS. 16E and 16F are perspective views of an exemplary adjusting pulley. FIG. 16G-16I are perspective views of a slider block, an adjustable pulley portion, and a base pulley portion, respectively, of an exemplary adjusting pulley.

FIG. 17 is a perspective view of an exemplary variation of a pulley arrangement that allows a drive member to be tensioned.

FIGS. 18A and 18B are side and perspective views, respectively, of an exemplary variation of a pulley arrangement that allows a drive member to be tensioned.

DETAILED DESCRIPTION

[0012] Examples of the various aspects and variations of the invention are described herein and illustrated in the accompanying drawings. The following description is not intended to limit the invention to these embodiments, but rather to enable a person skilled in the art to make and use this invention.

Robotic Arm Overview

[0013] Generally, a robotic or robotically assisted surgical system (eg, to enable a minimally invasive surgical procedure) may include one or more robotic arms for manipulation of surgical instruments, such as during minimally invasive surgery. As shown in FIG. 1A, a robotic arm 100 may include a plurality of links (eg, 112a, 112b, 112c, 112d, etc.) and a plurality of actuated linkages that allow relative movement between adjacent links. In addition, a tool driver 130 may be attached to a distal end of the robotic arm 100 and configured to hold and actuate a surgical instrument 140 passing through a cannula 150. During use of the robotic arm 100 for a surgical procedure, one end Proximal portion of robotic arm 100 may be mounted or otherwise attached to a structure (eg, a surgical table, cart, wall, ceiling, etc.) at a mounting point near the patient during a surgical procedure. Surgical instrument 140 may pass through cannula 150 through an incision or other point of entry into the patient. Generally, robotic arm 100 and/or tool driver 130 can be manipulated by a user to control surgical instrument 140 within the patient (eg, to perform surgical tasks, position a camera, etc.). Other examples of a robotic surgical system are described in concurrently filed US Patent Application No. 15/706,536 entitled "ROBOTIC ARMS" with Attorney Docket No. VESU-004/01 US 326240-2095, hereby referenced.

[0014] As shown in FIGS. 1A and 1B, robotic arm 100 may further include a passageway assembly 120. The passageway assembly may include a first end 126 coupled to a portion of the robotic arm, and a distal end 128 that is coupled to tool driver 130. As shown in FIG. 1B, the pitch assembly 120 may include at least a first pitch link 122 and a second pitch link 124 that drive the cannula in a particular direction P about a particular axis, referred to herein as a pitch axis (eg, depicted in FIG 1B passing through the page and coinciding with, or nearly coinciding with, a remote mechanical center of motion, or RCM). For example, the first pitch link 122, the second pitch link 124, and the tool driver 130 may move as three links of a four-bar link (eg, generally a parallelogram) that includes "ground" as a fourth. link, restrained with a drive mechanism (such as a pulley arrangement or other suitable pulley drive), in order to move the cannula about the pitch axis in a pitch direction P. Through this four-way linkage movement rods, the pitch assembly 120 can replicate the rotation of the first pitch link 122 about Axis A (illustrated in FIGS. 1C and 1D) in rotation of the cannula about the pitch axis (for example, about the mechanical RCM). , where Axis A and the pitch axis are generally offset and parallel. In some variations, the pitch set may include any suitable number of "n" links to form an n-bar link. Accordingly, activation of the first pitch link 122 about its first end 126 on Axis A can control a pitch movement of the cannula in the direction P. Although the pitch assembly 120 is primarily described herein as driving the cannula about of a pitch axis. It should be understood that in other variations or other orientations of the pitch assembly 120, the links 122 and 124 may be configured to drive the cannula about a particular axis in another direction (for example, a yaw axis), depending, for example, on how mount 120 is oriented, and so on.

[0015] Mounting passageway 120 may be configured to operate surgical instrument 140 on the RCM with greater ease, speed, and flexibility. Additionally, pitch assembly 120 may be configured to collapse into a compact configuration or position. For example, as shown in FIGS. 1C and 1D, the first pitch link 122 can be shorter than the second pitch link 124, so that the first pitch link 122 can rotate with relative to the second pitch link 124 without physical interference and allow the pitch assembly 120 to collapse or fold against itself. Such a configuration may be useful, for example, for storage, transportation, and/or increased range of motion of robotic arm 100, such as during a surgical procedure.

[0016] The tilt linkage assembly 120 may include a series of pulleys and a series of drive members (eg, metal bands, cables, chains, other suitable drive members, etc.) connecting the pulleys that facilitate movement. movement of the four-bar linkage. For example, with reference to FIGs.

1C and 1D, the first pitch link 122 may be coupled to an actuator (not shown) that drives rotation of the first pitch link 122 about Axis A, while the second pitch link 124 may be rotationally coupled to the tool driver. The first pitch link 122 may include a first pulley 162 coupled to the actuator and located generally at a point proximal to the first pitch link 122, within an internal space of the first pitch link 122 . The first pitch link 122 may also include a second pulley 164 located generally distal to the first pitch link 122, within the internal space of the first pitch link 122. The second pulley 164 may be rigidly attached to a proximal point of the second pitch joint 124.

[0017] In addition, the second pitch link 124 may include a third pulley 166 located generally at a point proximal to the second pitch link 124, mounted and rigidly attached to an axis of the first pitch link 122 that extends into an internal volume. of the second pitch link 124, such that when the first pitch link 122 rotates, the third pulley 166 rotates correspondingly. The second pitch link 124 may also include a fourth pulley 168 located generally at a distal point of the second pitch link 124, within the internal space of the second pitch link 124 . The tool driver can be rotationally coupled to the distal point of the second pitch link 124 and is therefore constrained to move when the fourth pulley 168 rotates about Axis A'.

[0018] At least one drive member (not shown) may wrap first and second pulleys 162 and 164 such that when an actuator drives rotation of first pitch link 122 at its first end 126 about axis A, the orientation of the second pitch link 124 remains fixed with respect to the orientation of the actuator housing. Similarly, at least one drive member (not shown) may wrap the third and fourth pulleys 166 and 168 such that when the second pitch link 124 rotates, the tool drive orientation remains fixed with respect to the tool drive orientation. first link 122 passing. In sum, the rotation of the first pitch link 122 about Axis A can be transformed through the system of pitch links, pulleys, and belts into the rotation of the tool driver about Axis A' by means of a four-bar linkage motion. (eg, in a parallelogram), and thus drives the cannula to move around the pitch axis as described above (eg, around a mechanical RCM). In some variations, the at least one drive member may include one or more cables, belts, and/or other suitable drive members or drive members.

[0019] For example, in the variation shown in FIGS. 15A and 15B, pitch assembly 1556 includes a first pitch link 1556a, a second pitch link 1556b, and a set of pulleys and drive members (eg, belts) configured to restrict movement of the pitch assembly in a similar manner. to the variation described above with reference to FIGS. 1C and 1D. In this variation, the first pitch link 1556a has a termination pulley 1510 configured to mate with a joint module actuator housing or other robotic arm chassis, and the first pitch link 1556a is rigidly attached to an adjustable pulley. 1514 located within the second through link 1556b. The second pitch link 1556b is rigidly attached to an adjustable pulley 1512 and further includes a termination pulley 1516 configured to engage a tool driver. The rotational movement of the various components may be facilitated by bearings, such as a bearing 1530a that facilitates relative movement of the rest of the robotic arm and the first pitch link 1530a, a bearing 1530b that facilitates relative movement between the first pitch links and second 1556a and 1556b and a bearing 1530c that facilitates relative movement of the second pitch link 1556b and the tool driver.

[0020] A pair of drive members (eg, belts or bands) 1520a and 1520b may extend between pulley termination 1510 and adjustable pulley 1512, with the first termination ends rigidly on pulley termination 1510 (for eg, joined by welding or other suitable connection) and second ends coupled to adjustable pulley 1512 (eg, by welding or other suitable connection). Similarly, a pair of drive members (eg, belts) 1522a and 1522b extend between termination pulley 1516 and adjustable pulley 1514, with the first ends terminating rigidly at termination pulley 1516 and the second ends attached to adjustable pulley 1514. As a result of the drive element and pulley system, as the first pitch link 1556a rotates about the termination pulley 1510, the second pitch link 1556b translates in-plane without rotating (i.e., remaining parallel to its previous orientation), while the termination pulley 1516 moves in an arc about the remote center of motion.

[0021] In some variations, a pulley arrangement (eg, pulley drive or other suitable pulley arrangement) on a robotic arm (eg, a pitch assembly) may include one or more attachment configurations for the coupling of a drive element to a pulley with increased resistance against shear forces that may otherwise tend to disengage the drive member from the pulley, cause multiple layers of a drive member (e.g., a stack of layers, as described in more detail below) to slide against each other, and/or cause loss of tension in the drive member, and in a manner that occupies less overall volume and/or occupies less surface area of the pulley. Additionally or alternatively, the pulley arrangement may include one or more tensioning mechanisms to adjust the tension in the driving member. For example, the drive member may be stressed to a predetermined stress during manufacturing, assembly, and/or calibration of the pitch assembly, to help protect and/or compensate for fatigue loads that may otherwise tend to cause the member loosening of the impeller and result in poorer operating performance in the pulley arrangement. Several examples of fastening configurations and tensioning mechanisms are described in more detail below.

Drive element and connection

[0022] In general, when a pulley arrangement is used, significant driving forces may be applied to the one or more driving members that at least partially enclose a pulley and/or the point of attachment of the drive element to the pulley. . For example, when the pulley arrangement is operated (eg, at least one pulley rotates), one or more drive members may be loaded in tension. As another example, when operating the pulley arrangement, one or more attachment points for a drive member (where a terminating end of the drive member is attached to a pulley) may be loaded with a shear force (for example, related to the tensile load in the driving member). If such forces are significant enough, they can cause the pulley arrangement to fail in one or more different ways. For example, the drive member may break if the driving forces exceed its tensile strength, or a point of attachment may fail if the shear forces exceed the shear strength of the joint between the terminal end of the drive member and the pulley. In some variations, a drive member may be wrapped more than once around the entire circumference of the pulley, which can help protect the attachment point from experiencing the full load of forces during operation of the pulley arrangement. pulley. However, even in these variations, the driving element and its attachment point to the pulley are still subject to failure due to the driving forces in the pulley arrangement, and the increased volume of the pulley arrangement due to the sheath. additional may be undesirable in some applications.

[0023] Also, in some applications, it may be advantageous to attach a drive element to a pulley using as small a pulley surface area as possible, in order to increase the amount of useful angular travel of the pulley (for less "dead" wrap or "static" wrap of the drive member) and thus allow the pulley arrangement (and, for example, a link assembly driven by the pulley arrangement) to have a greater range of motion.

[0024] Below are example variations of drive elements, and example variations of drive pulley element attachment arrangements that can be secure, compact, and/or take up less pulley surface area without sacrificing resistance to fixing the drive element to the pulley. It should be understood that while at least some of the fastening systems and methods are described herein primarily as attaching two ends of a drive member to a pulley, the same fastening systems and methods can be used to secure the ends of two members. separate drives to a pulley (ie, one end of a first drive member and one end of a second drive member to the pulley).

driving members

[0025] As shown in FIG. 2A, in some variations, a drive member 200 for a pulley arrangement may include a plurality of layers of one or more materials arranged in a stack such that a load (eg, tensile driving force) applied to the drive member is distribute through multiple layers. Generally, with multiple layers of materials sharing the load in such a way, the drive member as a whole can withstand a greater applied load before failing (eg, due to cyclic loading around the pulley and/or other factors). The layers of the pusher member may be attached to at least one terminating end of the pusher member. Additionally or alternatively, the layers of the pusher member may be joined along or part of the length of the pusher member in laminate.

[0026] In some variations, as shown in FIG. 2A, at least some of the layers of the drive member may include a first material 210 and a second material 220 that interlocks with the primary material. The first material 210 may function to support tensile loads applied to the drive member and may include, for example, metal, plastic, carbon fiber, and the like. The second material 220 may function as a shear substrate that increases shear strength at a point of junction. Second material 220 may include, for example, an adhesive solution (eg, a cyanoacrylate or other suitable liquid adhesive, a suitable epoxy or double-sided structural adhesive, etc.). As another example, as shown in FIG. 2B, the second material 220 may additionally or alternatively include particles 222 (eg, diamond particles, silicon carbide particles, etc.) suitable for deforming the lamination of the first material 210 so as to provide a physical connection between the layers. of the first material 210. The particles 222 can be mixed between a carrier solution of adhesive and/or non-adhesive materials, and the particles can be distributed and at least partially embedded in the adjoining surfaces of the first material 210 such that the particles become blocked. mechanically into the first material 210. In some variations, the particles 222 may generally have a diameter that is up to about half the thickness of the adjacent layer(s) of the first material 210. For example, in a variation, if a layer of the first material 210 includes a band about 0.002 inches thick, the particles 222 can be up to about 25 micrometers in diameter. Such a physical connection transfers mechanical forces between the layers of the first material 210 in response to applied shear forces, thus increasing the overall stiffness of the joint. various others Suitable mixtures of adhesive and/or non-adhesive solutions may be mixed with the particles and cured prior to or during lamination of the first material 210. Additionally or alternatively, the second material 220 may include a suitable filler material (eg, aluminum-silicon, copper or copper alloy, nickel alloy, etc.) to weld layers of the first material 210 together.

[0027] The dimensions and choice of material for a multilayer pusher member can be selected depending on the needs of the specific application. For example, the thickness of a multi-layer driving member may depend on various factors such as the anticipated loads the driving member is expected to withstand, the type(s) of material in each layer, the radius of the pulley, the thickness of each layer , the number of layers and the width of the driving member. As an example, generally, the overall thickness of the drive element in a pulley arrangement for a robotic arm can range from about 0.2 millimeters to about 1 millimeter, from about 0.4 millimeters to about 0.8 millimeters, or from about 0 .50 millimeters and approximately 0.7 millimeters.

[0028] In an exemplary variation, a multilayer drive member may include approximately six layers of metal (eg, 301-HY stainless steel), where each layer of metal may be approximately 0.05 thick. millimeters. The metal layers, at one end of the driving member, can be sandwiched with a mixture of cyanoacrylate adhesive and diamond particles. The diamond particles can have a diameter of about 0.5 microns or 0.6 microns.

[0029] In other variations, the actuation member may include any suitable number of layers (eg, at least two, three, four, five, or more layers). In addition, while exemplary multi-layer pusher elements are described above, variations of the attachment methods described below may be used in combination with any type of suitable pusher element (for example, a single layer of a belt or band) made with any kind of suitable material.

compressive union

[0030] In some variations not forming part of the invention, a termination end of a drive member may be attached to a pulley in the pulley arrangement through at least one compressive arrangement. A compressive arrangement can provide good resistance against fatigue from repeated operation of the pulley arrangement so that the drive member is less likely to loosen over time. Furthermore, a compressive arrangement can avoid weaknesses that can be introduced into the drive member material by other joining methods using welding, which can cause undesirable thermal stresses near the point of attachment of the drive member to the pulley. Also, when used in combination with fasteners or pins that pass through holes in the driving member, a compressive arrangement can exert a compressive force that provides good frictional contact to transfer loads, thereby reducing or eliminating stress concentration. around holes in the drive member that would otherwise contribute to drive member failure around the attachment point.

[0031] In general, a compressive arrangement for attaching a drive member to a pulley may include compressing at least a portion of the drive member (eg, a terminating end thereof) against the pulley. For example, at least a portion of the drive member and pulley may be sandwiched between two opposing surfaces. Opposing surfaces may, for example, be aligned and/or compressed with one another with a fastener such as a threaded member (eg, bolt or screw). Said fastener may be secured with a nut (eg lock nut, lock nut, etc.). As illustrated in more detail in the examples described below, at least one of the opposing surfaces may include, for example, an additional compression component, such as a washer or clamp plate, which increases the surface area and friction against it. pulley and/or drive member and thus increases the shear strength of the joint when the compressive arrangement is tightened and secured with the fastener. As another example, at least a portion of the drive member and pulley may be compressed against the pulley with a wedge or other suitable compression member. Other variations of compression arrangements for attaching a drive member to a pulley or other surface are described herein.

[0032] In an exemplary variant not forming part of the invention, as shown in FIGS. 3A and 3B, a compressive arrangement 300 for coupling a drive member to a pulley may include a pulley 310, a drive member 320, and a bracket 330. A suitable shear substrate (eg, as described above with reference to FIG. 2B) such as a cyanoacrylate adhesive may be disposed between pulley 310 and drive member 320 and/or between drive member 320 and bracket 330. The shear substrate between pulley 310 and drive member 320 may be different or substantially similar to the substrate shear between drive member 320 and clamp 330. As shown in FIG. 3A, at least one fastener 340 (eg, threaded screw) may pass through a hole 332 in the bracket, a hole 322 in the drive member, and a hole 312 in the pulley.

[0033] The clamp 330 may include a plate with holes 332 formed therein (eg, by machining, 3D printing, casting, etc.). Although clamp 330 is shown in FIGS. 3A and 3B as a generally flat or level plate with two holes 332, it is to be understood that in other variations, clamp 330 may be arcuate (eg, arcuate with a radius of curvature similar to that of pulley 310) and include any suitable number. from holes, such as two, three, four, five, six or more holes in any suitable pattern to accommodate any suitable number of fasteners 340. At least some of the holes 332 may, in some variations, be countersunk to receive fastener heads. fasteners 340 such that the fasteners 340 are generally flush with the surface of the clamp 330. The clamp 330 may include a material that is softer than the material of the pusher member so as not to deform the pusher member when the clamp 330 is tightened on. the driving member. The clamp may, in some variations, have a thickness generally equal to the thickness of the driving member, but may alternatively have any suitable thickness. In some variations, the circumferential length of the clamp 330 relative to the width of the drive member may be between about 1:1.5 and about 1:3, or about 1:2.

[0034] In some variations, the one or more holes 312 in the pulley 310 may be threaded to receive a threaded fastener 340 such that one or more fasteners 340 may hold and compress the clamp 330 and drive member 320 against the pulley 310 in a compressive arrangement, as fasteners 340 are advanced within holes 312. Additionally or alternatively, a nut 342 (eg, jam nut, lock nut, etc.) may engage a distal end of a fastener 340 to secure the parts of the clamped assembly. A threadlocking adhesive (eg, LOCTITE) may be applied, in some variations, to the threads of fastener 340 to further secure the fastened assembly against fatigue and loosening.

[0035] As shown in FIG. 3A, compressive arrangement 300 may include a plurality of fasteners 340 (eg, at least two, three, four, five, etc.) to secure the compressive arrangement of clamp 330, drive member 320, and pulley 310. The particular desired arrangement of fasteners (size, number, etc.) to attach the drive member 320 to the pulley without a weld can be evaluated based on the geometry and/or material properties of the drive member and fasteners, and their effect. on the stress experienced at the interface between the drive member and the fasteners.

[0036] For example, the mathematical expressions below can be used to determine the desired clamping diameter based at least in part on shear stress characterizations of the drive element and clamping elements, and on known geometries illustrated in FIG. 3B and other known material properties. The shear stress ^jf of the fasteners in the compressive arrangement can be expressed as shown in Equation (1) below:

where P ^f = force at shear location of fasteners, A ^f = area of fasteners at shear location, N ^f = number of fasteners, D ^f = diameter of each fastener, and of = maximum tensile strength ( UTS) of the fastener material.

[0037] Furthermore, the shear stress ^od of the driving member can be expressed as shown in Equation (2) below:

where P ^d = force at member shear location, driving A ^d = area of drive member at shear position, N ^d = number of layers in driving member at shear location, Y ^d = thickness of each ply in the driving member, X ^d = width of each ply in the driving member, N ^f = number of fasteners, D ^f = diameter of each fastener, and ^jd = ultimate tensile strength (UTS) of ply material of the driving member.

[0038] Assuming that, at the interface between the member and driving fasteners, the shear force ^Pf acting on the fasteners by the drive element is equal to the shear force ^Pd acting on the drive element. driven by the clamping elements, Equations (3) -(6) can be developed:

^{Pf = Pn} (3)

^of A ^f — ^od A ^d (4)

O p N p n ty 2 ^{= od} N ^d Y ^d ( X ^d - NpDp) (5)

^ D f 2 aDNDYDNFDp - oDNDYDXD = 0 ₍ 6 ₎

[0039] Using Equation (6), the desired diameter D ^f of each fastener can be determined using the quadratic formula

where

ffcNpn

a = ( ₄ 8 )

b = o DN DYDN f ( 9 )

c = ^od N ^d Y ^d X ^d ( 10 )

Equations (7)-(10) provide a positive value and a negative value, with the positive value being the desired fastener diameter based on the known or predetermined geometries and material characteristics of the driver and fasteners.

[0040] In other words, once the particular materials and geometries of the compressive arrangement are selected and known, Equations (1)-(10) can be applied to determine a desired fastener diameter for the compressive arrangement. Additionally, in some variations, the compressive arrangement may include fastener sizes that incorporate additional safety factors (eg, 1.5x, 1.75x, 2x, etc.) applied to the given diameter of the fastener. These safety factors can be incorporated to increase confidence that the drive member attachment to the pulley (via the compressive arrangement) will not fail during the expected use of the pulley arrangement. It should be understood that although Equations (1)-(10) are described with reference to compression arrangement 300, these equations are not necessarily applicable solely to compression arrangement 300, and may be modified to determine the desired parameters of other fastener arrangements described. here.

[0041] In another exemplary variation not forming part of the invention, as shown in FIGS. 4A-4D, a compressive arrangement 400 for coupling a drive member to a pulley may include a pulley 410, a drive member 420 with overlapping first and second ends 422 and 424, respectively, and at least two opposing surfaces secured by at least one fastener. 434 and nut 436 for fastening the overlapping ends of drive member 420 to pulley 410. As best shown in FIG. 4c, opposing surfaces on compressive arrangement 400 may include a first washer 430 and a second washer 432 disposed on opposite sides of pulley 410 and drive member ends 422 and 424. At least one of washers 430 and 432 may be a wave spring washer or similar, which imparts a spring pressure when compressed in the compressive arrangement, to increase the likelihood that the compressive arrangement will provide a positive compressive force at the attachment site over the life of the arrangement pulley.

[0042] In general, the fastener element 434 (eg, a threaded member such as a bolt or screw) may pass through the first washer 430, the pulley 410, through the first and second ends 422 of the element. drive member 420, through second washer 432, and through nut 436. In some variations, the diameter of the fastener may be less than or equal to about one-half the width of drive member 420. Nut 436, which is attached threaded with fastener 434, it can be tightened to clamp and secure pulley 410 and drive member ends together between first washer 430 and second washer 432. Nut 436 can be a locknut or locknut with threadlocker, etc. to help secure the location of the nut on the 434 fastener and maintain compressive strength.

[0043] In some variations, as shown in FIG. 4B, pulley 410 may include a recess to receive the fastener head (or alternatively, nut 436). Additionally or alternatively, as shown in FIG. 4D, pulley 410 may define a flat surface 412 against which fastener head 434 may bear so that the fastener does not rotate (eg, while or after the compressive arrangement is tightened). During assembly, washer 430 can be inserted through slot 414 in pulley 410 to position itself in the path of fastener 434.

[0044] In another exemplary variation, as shown in FIGS. 5A and 5B, a compressive arrangement 500 for coupling a drive member to a pulley may include a pulley 510, a drive member 520 with overlapping first and second ends 522 and 524, respectively, and at least two opposing surfaces secured by one or more bras. 534 and nuts 536 for fastening the overlapping ends of drive member 520 to pulley 510. As best shown in FIG. 5B, the opposing surfaces on the compressive arrangement 500 may include a washer 530 and a bracket 532 disposed on opposite sides of pulley 510 and drive member ends 522 and 524. Bracket 532 may, for example, be similar to bracket 330 described above with reference to FIGS. 3A and 3B.

[0045] In general, fasteners 534 may pass through clamp 532, through second and first ends 524 and 522, respectively, through pulley 510, through washer 530, and through middle of the nut 536. In some variations, the diameter of a fastener 534 may be less than or equal to about one-half the width of the drive member 520. In some variations, the fasteners 534 may be threaded (e.g., bolt or screw) and threaded with holes in pulley 510 and/or nuts 536. In other variations, one or more of fasteners 534 may be press-fit on pulley 510 to thereby secure drive member 520 against pulley 510.

[0046] As shown in FIG. 5A, the compressive arrangement 500 can be secured with more fasteners having smaller diameters rather than fewer fasteners having larger diameters. For example, compression arrangement 500 is shown as including five fasteners passing through a set of five respective holes in clamp 534 and drive member ends 522 and 544. Numerous smaller holes, rather than fewer holes larger, they can reduce stress concentration around holes that are more prone to failure (for example, in the event that the shear strength of the tie joint is overcome by the driving forces of the pulley arrangement) .

[0047] In another exemplary variation not forming part of the invention, as shown in FIGS. 6A-6D, a compression arrangement 600 for coupling a drive member to a pulley may include a pulley 610 having at least one projection 616, and a drive member 620 with first and second ends 622 and 624 where at least one of the First and second ends 622 and 624 at least partially enclose a projection 616 on pulley 610. In the variation shown in FIG. 6C, each of pusher member ends 622 and 624 may wrap around a respective projection 616. Compressive arrangement 600 may further include at least two opposing surfaces secured by at least one fastener 634 and nut 636 for fastening pusher member ends 622. and 624 on projections 616 of pulley 610. As best shown in FIG. 6C, the opposing surfaces on the compressive arrangement 600 may include a first clamp 640 disposed on a first side (eg, the inner side) of projections 616 and a second clamp 642 disposed on a second side (eg, the outer side). ) of projections 616. Brackets 640 and 642 may, for example, be similar to bracket 330 described above with reference to FIGS. 3A and 3B. The first clamp 640 may be configured to compress portions of the pusher member ends 622 and 624 against the first side of projections 616. The second clamp 642 may be configured to compress portions of the pusher member ends 622 and 624 against the second side of projections 616. projections 616. Generally, fastener 634 may pass through clamps 640 and 642 and nut 636 to compress and secure the ends of the drive member around projections 616 on the pulley.

[0048] Additionally or alternatively, the opposing surfaces on the compressive arrangement 600 may include a first washer 630 and/or a second washer 632. At least one of the washers 630 and 632 may be a wave spring washer or the like, which imparts a spring pressure when compressed in the compressive arrangement, to increase the probability that the compressive arrangement will provide a positive compressive force at the attachment site throughout the life of the pulley arrangement.

[0049] Additionally or alternatively, the opposing clamping surfaces of drive member ends 622 and 624 on projections 616 of pulley 610 may be on fastener 634 itself. For example, the head of fastener 634 may be shaped (eg, machined) to match the curvature of pulley 610, and be large enough to provide sufficient compressive force on the clamp member ends. drive 622 and 624.

[0050] In some variations, similar to those described above with reference to FIG. 4B, pulley 610 may include a recess to receive the fastener head (or alternatively, nut 636). Additionally or alternatively, as shown in FIG. 6D, pulley 610 may define a flat surface 612 against which fastener head 634 may bear so that the fastener does not rotate (eg, while or after the compressive arrangement is tightened). During assembly, washer 630 and/or clamp 640 may be inserted through a slot 614 in pulley 610 to position itself in the path of fastener 634.

[0051] In another exemplary variation not forming part of the invention, as shown in FIG. 7, a compressive arrangement 700 is similar to a compressive arrangement 600, except as described below. Compressive arrangement 700 for coupling a drive member to a pulley may include a pulley 710 having at least one projection 716, and a drive member 720 with first and second ends 722 and 724 where at least one of first and second ends 722 and 724 at least partially surrounds a projection 716 on pulley 710. In the variation shown in FIG. 7, each of the pusher member ends 722 and 724 may wrap around a respective projection 716. Compression arrangement 700 may further include a wedge 750 configured to compress the ends 722 of the drive member against projections 716. For example, wedge 750 may be generally prismatic with tapered edges such that the wedge tapers in width along its length. in a radial direction. Alternatively, wedge 750 may be conical or frustoconical, etc. The wedge may be made of a high friction material such as rubber or other suitable material. A fastener 734, secured by nut 736, can pass through a wedge lumen 750 between the projections 716 such that when the fastener is tightened, the wedge 750 is pushed radially and its increasing width at the points of contact with the drive member ends 722 and 724 causes the wedge 750 to compress further the ends 722 and 724 of the drive member against projections 716 on the pulley.

[0052] Compression arrangement 700 may further include at least one clamp 740 disposed on an inner side of projections 716 to help secure the ends of the drive member to the pulley. Claim 740 may, for example, be similar to clamp 330 described above with reference to FIGS. 3A and 3B. Additionally or alternatively, the compressive arrangement 700 may include a first washer 730 and/or a second washer 732. At least one of the washers 730 and 732 may be a wave spring washer or the like, which imparts spring pressure when compressed. in the compressive arrangement, to increase the probability that the compressive arrangement will provide a positive compressive force at the attachment site throughout the life of the pulley arrangement.

[0053] In another exemplary variation not forming part of the invention, as shown in FIG. 8, a compressive arrangement 800 is similar to a compressive arrangement 700, except as described below. For example, compression arrangement 800 may include a pulley 810 having at least one projection 816, and a drive member 820 with first and second ends 822 and 824, where at least one of the first and second ends wraps at least partially around of a projection on pulley 810. Compression arrangement 800 may further include a wedge 850 such as is similar to wedge 750 described above with reference to FIG. 7. A threaded fastener 834, secured at one end with a nut 836, can pass through a lumen in wedge 850 and into a threaded hole in pulley 810. As the fastener is tightened (eg. , nut 936 and washer 832 advance against wedge 850), wedge 850 is pushed radially and its increasing width at the points of contact with the drive member ends 822 and 824 causes wedge 850 to further compress the drive ends. drive element 822 and 824 against projections on pulley 810. In FIG. Another exemplary variation of a compression arrangement 900 is shown in Figure 9. The compression arrangement 900 is similar to the compression arrangement 800, with similar numbered elements as the compression arrangement 800, except that the drive member ends 922 and 924 wrap less around of projections 916 compared to ends 822 and 824 of the drive member as shown in FIG. 8.

[0054] In another exemplary variation not forming part of the invention, as shown in FIG. 10A, a compressive arrangement 1000 may include a block 1010 (eg, part of a pulley or a component attached to a pulley) having one or more deformable pins 1034, a drive member 1020, and a clamp 1030. The pins 1034 may, for example, be machined from block 1010, and/or may be pins that are inserted into respective holes in block 1010 (eg, by press fit, etc.). The pins can be received through holes 1022 in drive member 1020 and holes 1032 in bracket 1030 in the arrangement of FIG. 10B. As shown in FIG. 10B, block 1010 and bracket 1030 may have mating surfaces that interpose and compress the drive member on opposite sides of the drive member.

[0055] As shown in FIG. 10C, a compressive force F can be applied to the block and clamp assembly to deform at least one of the pins 1034 into a rivet or rivet-like shape that secures the drive member 1020 against the block 1010. For example, the force Compression F may be applied by a clamp with one or more recesses, each recess receiving a respective distal end of a pin 1034 such that the recess molds or otherwise forms the distal end of the pin 1034 into a rivet or pin shape. rivet. The compression force F may be applied to multiple (two or more, or all) pins 1034 simultaneously, or may be applied to each pin sequentially.

[0056] Furthermore, although block 1010 and bracket 1032 are shown in FIG. 10A with mating flat surfaces, it is to be understood that, in other variations, they may have angled surfaces, curved surfaces (eg, arcuate with the same radius of curvature), or other suitable mating surfaces. The particular dimensions, number, materials, etc. of the pins in the block can, in some variations, be selected based on an analysis of parameters such as those used in Equations 1-10 as described above.

[0057] In some example variations, the block 1010 and pins 1034 may be made of stainless steel (eg, 304SST) or carbon steel, with or without additional alloying elements (eg, high-grade low-alloy steel). strength, which may include, for example, additional alloying elements such as manganese, copper, titanium, vanadium, niobium, etc. to carbon or any suitable material The clamp may be made of annealed steel (eg AISI 1010) or other suitable material which may be relatively soft (eg, to provide enough contact to improve friction.) As shown in FIG 10A, block 1010 may include five pins, each with a diameter of approximately 1 mm, and may be arranged in a bilaterally symmetrical pattern, such as with four pins at four corners of a rectangle measuring about 4 mm x about 3 mm and a fifth pin in the center of the rectangle. Forming the pins to deform the pins into rivets or rivet-like shapes can be formed one at a time under a compressive force of about 1500 N. In these variations, each forming operation can achieve, for example, about 300 N of the clamping force to secure the drive element 1032 to the block 1010.

welded joint

[0058] In some variations not forming part of the invention, a terminating end of a drive member may be attached to a pulley in the pulley arrangement by at least brazing. The drive member may include multiple layers of a metallic material that are brazed together with a brazing alloy filler material, and the drive member may be further attached to a pulley or other component by brazing with the same or different material. brazing alloy filler. The resulting welded joint can be as strong or stronger than the full cross-sectional strength of all the metal strips.

[0059] For example, as shown in FIG. 11, a multilayer drive member 1120 (eg, similar to that described above with reference to FIGS. 2A and 2B) may be welded to a metal block 1110. The metal block 1110 may be part of a pulley or a component. attached to a pulley. The multilayer driving member may be welded to an arcuate segment of the block forming an angle A, where the angle A may be, for example, between about 10 degrees and 25 degrees, or between about 15 degrees and about 20 degrees. The multilayer drive member 1120 may include at least one metal belt layer 1122 and at least one filler layer 1124. The metal belt layers 1122 may include stainless steel or other suitable material. Filler layers 1124 may include a suitable brazing alloy such as aluminium-silicon, copper or copper alloy, nickel alloy, etc. Although FIG. 11 depicts a drive member 1120 with two metal layers and two filler layers 1124, it should be understood that any suitable number of metal belt layers and/or filler layers may be included.

[0060] In some example variations, block 1010 is an arcuate segment of stainless steel (eg, 304SST) or carbon steel, with or without additional alloying elements. The multilayer drive member may include multiple strips of metal (eg, 301-HY stainless steel) that are welded together with a filler material. In addition, the multi-layer driving member can be welded along the arc length of block 1010 sweeping about 17.5 degrees. In one example, the drive member may include up to about five layers of metal belt material, each about 0.13mm thick and about 6mm wide. As another example, the drive element may include up to about twelve layers of metal belt material, each about 0.05mm thick and about 6mm wide. These examples can result in a brazed joint having a shear strength of approximately 6,800 N.

Tensioning mechanisms

[0061] The tension variations of the mechanisms in the pulley arrangements that allow the tensioning of the members attached to one or more drive pulleys are described below. Generally, properly tensioned drive members help facilitate rotational movement within a pulley arrangement (eg, within a pitch assembly such as pitch assembly 120 described above with reference to FIGS. 1C and 1D).

[0062] In some variations, the one or more drive members may be stressed to a predetermined stress level at least during manufacturing, assembly, and/or calibration of the pitch assembly. Additionally or alternatively, the one or more drive members may be monitored and re-tensioned during the course of use of the robotic arm. For example, during the operation of a pulley arrangement, fatigue loads applied to the pulley arrangement over an extended period of time can cause one or more drive members to loosen and lose their tension, resulting in poor performance. poor pulley arrangement (eg, lower positional accuracy, slower actuation response times, etc.). Therefore, periodic or intermittent tensioning of one or more drive members may be desired to maintain performance. Additionally or alternatively, at least a portion of the pulley assembly may be swapped out to be replaced with properly tensioned pulley assembly parts, as part of regular maintenance.

[0063] Accordingly, in some variations, a pulley arrangement (such as one included in pitch assembly 120 as shown in FIGS. 1C and 1D on a robotic arm) may further include a tensioning mechanism. For example, the tensioning mechanism may include at least one idler pulley located in plane with the first and second pulleys 162 and 164 and one or more corresponding belts, and at least one idler pulley located in plane with the third and fourth pulleys 166 and 168. and one or more corresponding bands. The in-plane locations of the idler pulleys can be adjusted and configured (for example, with fasteners) to calibrate the tension of the belts. However, the passageway assembly 120 may include a tensioner or any suitable tensioner assembly. Other exemplary variations of tensioning mechanisms, such as those described below, may be incorporated into the pulley arrangement.

split pulleys

[0064] In some variations that are not part of the invention, as shown in FIG. 12A, a pulley arrangement 1200 may include an adjusting pulley 1210 and an idler pulley 1230 that are connected through a first drive member 1220 and a second drive member 1220'. A first end 1222 of a first drive member 1220 may engage and wrap at least partially around the adjustment pulley 1210, and a second end 1224 of the first drive member 1220 may engage and at least partially wrap around the idler pulley 1230. Similarly, a first end 1222' of a second drive member 1220' may engage and at least partially wrap around the idler pulley. 1210, and a second end 1224' of second drive member 1220' may engage and wrap at least partially around idler 1230. Alternatively, adjusting pulley 1210 and idler 1230 may be connected via a single member. drive member 1220, with a first end 1222 of drive member 1220 engaged and at least partially wrapped around adjusting pulley 1210, a body part of drive member 1220 enclosing idler pulley 1230, and a second end 1224 of drive member 1220 attached and wrapped at least partially around adjustment pulley 1210. Any suitable attachment mechanism or arrangement, including any of the vari The drive member attachment features described herein can be used to couple one end of one or both of the drive members to the idler pulley and/or idler pulley. The pulley arrangements with adjusting pulleys described below can, for example, be used to adjust the tension in the drive member in those variations where the idler pulley may be a fixed distance from the base pulley portion (although in some variations the position of the idler pulley can be adjustable in distance from the base pulley part, so as to further adjust the tension in the driving member(s).

[0065] In some variations, a pulley arrangement may include an adjusting pulley for adjusting the tension in the pulley arrangement, the adjusting pulley including a base pulley portion rotatable within a driving plane, and a pulley portion adjustable coupled to the base pulley part. The adjustable pulley portion may be rotatable relative to the base pulley portion within the driving plane. The pulley arrangement may further include a drive member comprising a first end coupled to the adjustable pulley portion, wherein at least a portion of the drive member is at least partially wrapped around the adjustable pulley portion. In FIGS. 12A-12C and FIGS. Examples of these variations are shown in 14A-14B.

[0066] As shown in FIGS. 12A-12C, a pulley arrangement may include a base pulley portion 1212, an adjustable pulley portion 1214 rotatable relative to base pulley portion 1212, and at least one drive member 1220 having a first end 1222 attached and wrapped. at least partially around the adjustable pulley portion 1214. Another drive member end 1222' (of the same drive member 1220 or another drive member 1220') may be attached to the base pulley portion 1212 and wrap at least partially around the base pulley portion. base pulley portion 1212. The base pulley portion and the adjustable pulley portion may be generally circular or arcuate. For example, the base pulley portion and/or the adjustable pulley portion may be ring-shaped or partial ring-shaped as shown in FIGS. 12B and 12C. Alternatively, the base pulley part and/or the adjustable pulley part may be in the form of a disc or a partial disc with an arcuate edge.

[0067] As shown in FIG. 12A, base pulley portion 1212 may include a mounting region 1212a and a drive region 1212b. Mounting region 1212a may be configured to mount base pulley portion 1212 to a surrounding structure (eg, an arm segment such as a pitch link on a robotic arm), such as with fasteners. Drive region 1212b may include an arcuate surface configured to engage drive member 1220. For example, drive member 1220 may at least partially enclose the arcuate surface of drive region 1212b. In some variations, drive region 1212b may be a surface that is at least about the width of drive element 1220.

[0068] Like base pulley portion 1212, adjustable pulley portion 1214 may include a mounting region 1214a and a driving region 1214b. Mounting region 1214a may be configured to couple adjustable pulley portion 1214 to base pulley portion 1212. For example, as shown in FIG. 12B, one or more fasteners 1213 (eg, screws, bolts, etc.) may pass through openings 1215 and into threaded holes (not shown) in base pulley portion 1212, in order to axially restrain the pulley. adjustable pulley portion 1214 relative to base pulley portion 1212. Drive region 1214b may include an arcuate surface configured to engage drive member 1220. For example, drive member 1220 may wrap at least partially around of the arcuate surface of the drive region 1214b. In some variations, drive region 1214b can be a surface that is at least about the width of drive member 1220. In addition, as shown, for example, in FIG. 12C, one end of drive member 1220 may be coupled (for example, with any of the attachment arrangements described herein, or in any suitable manner) to drive region 1214b at point A of adjustable pulley portion 1214.

[0069] The adjustable pulley driving region 1214b and the base pulley portion driving region 1212b may, in combination, approximate at least part of a circle. For example, drive region 1214b and drive region 1212b may be nearly semicircular. As another example, driving region 1212b may sweep a major arc while driving region 1214b sweeps a minor arc, or vice versa. As yet another example, both drive region 1214b and drive region 1212b can sweep a minor arc. Adjustable pulley portion 1214 and base pulley portion drive region 1212b may be generally coaxial and have approximately the same radius of curvature, such that a drive member 1220 and/or drive member 1220' can rotate with the arrangement. pulley at a constant rate of travel.

[0070] Adjustable pulley portion 1214 may be configured to rotate relative to base pulley portion 1212. As described above, one end of drive member 1220 may be attached to and at least partially wrapped around the drive portion. adjustable pulley 1214, and the other end of drive member 1220 can be attached to a location on the ground (eg, idler pulley 1230 as shown in FIG. 12A or point B on base pulley portion 1212 as shown in FIG. 12C). In such an arrangement, the adjustable pulley portion 1214 may be radially constrained to rotate relative to the base pulley portion by a kinematic constraint between the pulley portions and belt tension.

[0071] Furthermore, rotation of the adjustable pulley portion 1214 in a particular direction relative to the base pulley portion 1212 may put the drive element 1220 under stress. In some variations, the pulley arrangement may include a movable engaged with the adjustable pulley portion, wherein the movable member may be adjustable to thereby rotate the adjustable pulley portion 1214 relative to the base pulley portion 1212. For example, the movable member may include a threaded member 1216 (e.g. , a carriage bolt, or other suitable fastener). One end of threaded member 1216 may engage base pulley portion 1212, and another end of threaded member 1216 may contact adjustable pulley portion 1214. Advancement and/or retraction of threaded member 1216 may cause displacement of the adjustable portion of pulley 1214.

[0072] FIGS. 13A-13C not forming part of the invention depict various exemplary rotational positions of adjustable pulley portion 1214 corresponding to different levels of tension in drive member 1220. In FIG.

13A, the adjustable pulley portion 1214 is in a rotational position corresponding to a relatively low amount of tension in the drive member. Threaded member 1216 is in a retracted state. In this rotational position, fasteners 1213 that axially couple adjustable pulley portion 1214 to base pulley portion 1212 are generally located at a first end (eg, the right end, as shown in FIG. 13A) of slot openings 1215.

[0073] In FIG. 13B, the adjustable pulley portion 1214 is in a rotational position corresponding to a moderate amount of tension in the drive member. Threaded member 1216 advances upwardly (in the orientation shown in FIG. 13B) a moderate distance to thereby rotationally displace adjustable pulley portion 1214 in a clockwise direction. In this adjusted rotational position, the adjustable pulley portion 1214 causes the end of the drive member 1220 attached at "A" to be closer to the end of the drive member attached at "B", which increases the tension in the drive member. In this rotational position, the fasteners 1213 are generally located in the middle of the slot openings 1215. In FIG. 13C, the adjustable pulley portion 1214 is in a rotational position corresponding to a relatively high amount of tension in the drive member. Threaded member 1216 advances further than in FIG. 13B to further move the adjustable pulley portion 1214 in a clockwise direction. In this adjusted rotational position, the adjustable pulley portion 1214 causes the end of the attached drive member at "A" to be even closer to (eg, adjacent to) the end of the attached drive member at "B", further increasing more stress on the driving member compared to the arrangement of FIG. 13B. In this rotational position, the fasteners 1213 are generally located at a second end of the slot openings 121. The three voltage levels are depicted in FIGS. 13A-13C as illustrative examples. It should be understood that the possible selectable voltage range in the drive member may be continuous and include voltage levels between those depicted in FIGS. 13A-13C. Furthermore, in some variations, stress levels beyond the low and high stress levels depicted in FIGS. 13A and 13C. For example, adjustable pulley portion 1214 may be positioned in a more counterclockwise position than in FIG. 13A, which corresponds to an even lower stress level in the drive member. As another example, such as if the driving regions 1212b and 1214b (of the base pulley portion and the adjustable pulley portion, respectively) could overlap, the adjustable pulley portion 1214 can be positioned in a more clockwise position. clockwise than FIG. 13C, which allows the ends of the drive member at "A" and "B" to overlap and result in an even higher stress level on the drive member compared to FIG. 13C. Also, in some variations, the possible selectable voltage range may be discrete (eg, by detents in openings 1215, etc.).

[0076] As shown in FIGS. 13A-13C, in some variations, the threaded member 1216 may include a hemispherical head 14 configured to contact the adjustable pulley portion at a point tangential to the position of the adjustable pulley portion 1214. Upon contacting the adjustable pulley portion 1214 only at a single point as the adjustable pulley part's rotational position varies, the hemispherical head of the threaded member 1216 can help ensure proper kinematic coupling between the base pulley part, the adjusting pulley part, and the adjusting pulley part. threaded member 1216. In some variations, the hemispherical head of threaded member 1216 may have a single radius of curvature such that the linear rate of displacement of threaded member 1216 corresponds to a constant rate of rotational travel of the adjustable pulley portion, and therefore results in a constant amount of tension per unit travel of the threaded member 1216. In other words, the relationship between a unit of linear travel of the threaded member 1216 and a unit of rotational travel of the adjustable pulley portion may be generally constant while the head of the threaded member 1216 and the adjustable pulley portion are in contact.

[0077] Furthermore, in some variations, as shown in FIGS. 13A-13C, threaded member 1216 may include one or more features that can be engaged to advance and/or retract threaded member 1216 relative to the base pulley portion. For example, threaded member 1216 may include along its length one or more flat surfaces that can be grasped with a clamp, wrench, or other suitable tool from a lateral or radial approach to the length of the threaded member (eg, , since the head of threaded member 1216 may be at least partially obstructed by the adjustable pulley portion). Such a tool can be used to grasp and rotate threaded member 1216 to advance and/or retract threaded member 1216. Alternatively, a bottom of the threaded member head, or other suitable portion of the threaded member, may engage to advance and/or retract the threaded member and rotate the adjustable pulley portion 1214.

[0078] The adjustable pulley portion may be lockable in a selected rotational position relative to the base pulley portion, thus establishing a selected level of tension in the drive member. For example, once the rotational position of the adjustable pulley portion is selected, the fasteners 1213 can be tightened into their locations in the slot openings 1215 to thereby lock the adjustable pulley portion in the selected rotational position. (and lock the selected tension level in the driving member). Therefore, by moving the adjustable pulley part and locking its rotational position, the drive member tension can be adjusted and locked during assembly of the pulley arrangement (for example, as part of the manufacturing process), during a calibration procedure and/or during maintenance, etc.

[0079] Another variation of a pulley arrangement 1400 that is not part of the invention is shown in FIGS. 14A and 14B. Pulley arrangement 1400 is similar to pulley arrangement 1200 shown in FIG. 12A except as described below with similar element numbering. For example, pulley arrangement 1400 may include an adjusting pulley 1410 and an idler pulley 1430 that are connected by at least one drive member 1420. Any suitable attachment mechanism or arrangement may be used, including any of the attachment variations of the drive member described herein for coupling one end of one or both of the drive members to the adjusting pulley and/or the idler pulley. The pulley arrangements with adjusting pulleys described below can, for example, be used to adjust the tension in the drive member in those variations where the idler pulley may be a fixed distance from the base pulley portion (although in some variations the position of the idler pulley can be adjustable in distance from the base pulley part, so as to further adjust the tension in the driving member(s).

[0080] As shown in FIG. 16D, idler pulley 1630 may include a base 1632 and a flange 1634 axially aligned and coupled to base 1632. Base 1632 may include a drive region around which at least part of drive member 1620 and/or drive member 1620 ' may be wrapped. The ends of drive members 1620 and/or 1620' may be attached to base 1632 by anchor blocks 1622 engaged with base 1632, or in any suitable manner (eg, attachment methods described herein). Flange 1634 may, for example, provide a wall that guides the drive elements along the drive region of base 1632 and helps prevent the drive elements from falling out of plane with the pulley arrangement.

[0081] Pulley arrangement 1400 may include an adjusting pulley 1410 as shown in FIG. 14B. Adjusting pulley 1410 may include a base pulley portion 1412 and an adjustable pulley portion 1414 rotatable with respect to base pulley portion 1412. At least one drive member (not shown) may have a first end coupled to ( for example, at location 'A') and wrap at least partially around the adjustable pulley portion 1414. Another drive member end may be attached to (for example, at position 'B') and wrap at least partially around of the base pulley part of 1412.

[0082] As shown in FIG. 14B, adjustable pulley portion 1414 may include a plurality of openings 1415 through which fasteners can axially couple adjustable pulley portion 1414 to base pulley portion 1412. The plurality of openings 1415 may be selectively aligned with one or more openings. in the base pulley portion 1412. Each of the openings 1415, when aligned with an opening in the base pulley portion 1412, may correspond to a respective rotational position of the adjustable pulley portion 1414 with respect to the adjustable pulley portion. base 1412, and thus may correspond to a respective level of tension in the driving member. Similar to the pulley arrangement 1200 described above, the selected rotational position of the adjustable pulley portion 1414 can be locked by tightening a fastener or pin (not shown) in the aligned holes to thereby lock the drive member tension. Additionally or alternatively, base pulley portion 1412 may include a plurality of openings that selectively align with one or more openings in adjustable pulley portion 1414 to provide multiple potential adjustable pulley portion 1414 rotational positions and tension levels. in the drive member. In some variations, adjustable pulley portion 1414 and/or base pulley portion 1412 may include openings 15 arranged similar to a Vernier scale to provide many options for discrete levels of tension in the drive member.

Angled Surface Pulleys

[0083] The embodiment of a pulley arrangement 1600 according to the invention is shown in FIGS.

16A and 16B. Pulley arrangement 1600 is similar to pulley arrangement 1200 shown in FIG. 12A except as described below with similar element numbering. For example, pulley arrangement 1600 may include an adjusting pulley 1610 and an idler pulley 1630 that are connected by at least one drive member 1620 (eg, drive member 1620 and second drive member 1620'). Any suitable attachment mechanism or arrangement, including any of the drive member attachment variations described herein, may be used to couple an end of one or both of the drive members to the adjusting pulley and/or idler pulley. The pulley arrangements with adjusting pulleys described below can, for example, be used to adjust the tension in the drive member for those variations where the idler pulley may be a fixed distance from the driving portion. base pulley (although in some variations the position of the idler pulley may be adjustable in distance from the base pulley portion, such as to further adjust the tension in the driving member(s).

[0084] As shown in the exploded view of FIG. 16B and the assembled views of FIGS. 16E and 16F, the adjusting pulley 1610 may include a base pulley portion 1640 rotatable about an axis, an adjustable pulley portion 1650 coupled to the base pulley portion, and at least one slider block (eg, slider blocks 1660a). and 1660b) engaged with adjustable pulley portion 1650. As shown in FIG. 16F, adjustable pulley portion 1650 can move in a first direction (eg, "Z" direction) parallel to the axis of rotation of base pulley portion 1640. The at least one slider block can be configured to move in a second direction. (eg, "R" direction) different from the first direction, in response to compression of adjustable pulley portion 1650 against base pulley portion 1640. In some variations, the first and second directions may be generally orthogonal to each other .

[0085] Base pulley portion 1640 may be configured to fixedly mount, for example, to a distal end of a pitch link (eg, pitch link 1512 shown in FIG. 15A) or other portion of a pitch link. robotic arm. As shown in FIG. 16I, base pulley portion 1640 may have a mounting face configured to engage adjustable pulley portion 1650 and slide blocks 1660a and 1660b. The mounting face may include, for example, at least one ridge or other guide 1642 configured to engage slide blocks 1660a and 1660b. Base pulley portion 1640 may be a generally circular plate or disc as shown in FIG. 16I, but may alternatively be of any suitable shape with one or more mounting features. In some variations, cutouts in the material of the base pulley portion 1640 can help reduce the weight of the overall fit pulley assembly. The base pulley portion may be equipped with one or more pins 1646 configured to engage holes 1656 in the adjustable pulley portion 1650 so that the adjustable pulley portion 1650 rotates in 1:1 correspondence with the base pulley portion 1640. The pins 1646 can transfer torque from the base pulley portion 1640 to the adjustable pulley portion 1650, while allowing the adjustable pulley portion 1650 to move axially closer to and/or further from the bearing portion. base pulley 1640.

[0086] As shown in FIG. 16H, adjustable pulley portion 1650 may be generally circular (eg, ring or plate) and may have a drive region 1652 on an outer surface of adjustable pulley portion 1650, around which one or more driven members wrap. . The adjustable pulley portion 1650 may mate and connect with mounting features of the base pulley portion 1640, such as with fasteners 1650 (eg, screws) that pass through holes 1658 in the adjustable pulley portion and are engage threaded holes 1644 in base pulley portion 1640. In addition, adjustable pulley portion 1650 may have an arcuate gap between spaced apart surfaces 1654. Surfaces 1654 may be sloped (e.g., helical surfaces) complementary to surfaces inclined 1664 (eg, helical surfaces) of sliding blocks 1660a and 1660b.

[0087] As shown in FIGS. 16E and 16F, slide blocks 1660a and 1660b may be disposed in the arcuate space between spaced surfaces 1654. Slots 1666 in the slide blocks may engage outwardly projecting guide 1642 on the base pulley portion (although alternatively , the guide 1642 may be a slot and the slide blocks may include an outwardly projecting guide). With reference to FIG. 16G, one end of a pusher member may be attached to a pusher region 1662 on an outer surface of slider block 1660b. Similarly, one end of the same or another drive member may be attached to a drive region on an outer surface of slider block 1660a. The drive regions of adjustable pulley portion 1650 and slider blocks 1660a and 1660b may be aligned to facilitate a smooth transition for a drive member to wrap around the drive regions.

[0088] Adjusting pulley 1610 may facilitate bilateral tensioning of drive members 1620 and 1620. In general, as shown in FIG. 16F, an input force can apply compression of adjustable pulley portion 1650 against base pulley portion 1640 and move adjustable pulley portion 1650 in the "Z" direction (thereby bringing adjustable pulley portion 1650 and base portion 1650 closer together). base pulley 1640 in closest approach to each other). The input force can be applied by tightening fasteners 1670 to tighten the adjustable pulley portion 1650 against the base pulley portion 1640. This axially directed input force is translated, by sloped mating surfaces 1654 (on the adjustable pulley portion). and 1664 (on the slider blocks), to move the slider blocks circumferentially together. In other words, in response to this input force in the "Z" direction, the first and second slider blocks 1660a and 1660b are configured to move circumferentially or arcing toward each other in the "R" directions, thus carrying the ends of the drive member (attached to the slider blocks) together and applying tension to the drive member(s). If the helical surfaces 1664 on the slider blocks 16 are similar in slope, etc. (eg, slider blocks 1660a and 1660b are mirror images of each other), then slider blocks 1660a and 1660b may move circumferentially or arc toward each other at approximately equal speeds. If the helical surfaces 1664 of the slider blocks do not have a similar slope, then the slider blocks 1660a and 1660b may move circumferentially or arc toward each other at different speeds.

[0089] When a desired level of tension in the drive element or members is achieved with a particular axial position of the adjustable pulley portion 1650 relative to the base pulley portion 1640, one or more of the fasteners 1670 can be fixed to lock the tensioner level. For example, the axial position of the fasteners 1670 can be fixed with a lock nut, threaded lock nut, etc.

[0090] Therefore, a single input action of bringing the adjustable pulley part and the base pulley part closer together results in hardening of the drive members, which can improve ease of installation and maintenance over the life of the drive mechanism. pulley. Also, with symmetrical slider blocks, the same tension can be applied to both belts, which can improve the load capacity and life of the pulley mechanism. Furthermore, within a single pulley arrangement including an adjustable pulley and an idler pulley, advantageously only one pulley may be required to provide adjustable termination of the belts.

[0091] Another variation of an adjustment pulley 1710 that is not part of the invention is shown in FIG. 17. The 1710 Idler Pulley is similar to the 1610 Idler Pulley, except as described below, with similar item numbering. In the adjustment pulley 1710, the adjustable pulley portion includes two members 1750a and 1750b. First member 1750a may engage first slider block 1760a, and second member 1750b may engage second slider block 1760b. Similar to the adjustable pulley portion 1650 described above, members 1750a and 1750b can move parallel to the axis about which the base pulley portion 1740 rotates. As the first member 1750a moves in such an axial direction toward the base pulley 1740, the sloped (eg, helical) interfacing surfaces of the first member 1750a and first slider block 1760a can be translated into circumferential or arcuate motion of the first slider block 1760a toward the second slider block 1760b. Similarly, when second member 1750b is moved in an axial direction toward base pulley portion 1740, the interface sloped (eg, helical) surfaces of second member 1760b and second slider block 1760b may translate into a circumferential or arcuate movement of the second slider block 1760b toward the first slider block 1760a. Thus, like the adjustment pulley 1610 described above, a single input action of bringing the adjustable pulley portion and the base pulley portion closer together on the adjustment pulley 1710 results in tightening of the drive members.

[0092] Members 1750A and 1750b are movable independent of one another, which may allow independent tensioning of the drive member ends coupled to each member 1750A and 1750b. In addition, members 1750a and 1750b may move in tandem, which may allow simultaneous tensioning of the drive member ends coupled to members 1750a and 1750b.

[0093] When a desired level of tension in the drive element or members is achieved with a particular axial position of the adjustable pulley portion relative to the base pulley portion 1740, one or more of the fastener elements 1770 can be set to lock the tension level. For example, the axial position of fasteners 1770 can be fixed with a lock nut, threaded lock nut, etc.

[0094] Another variation of an idler pulley 1810 that is not part of the invention" is depicted in FIGS. 18A and 18B. The idler pulley 1810 is similar to the idler pulley 1810, except as described below, with similar numbering of elements.In the adjustment pulley 1810, the adjustable pulley portion includes two members 1850a and 1850b, each of which is disposed in a recess in the base of the pulley portion 1840 so that the adjustable pulley portion adjustable pulley and base pulley portion 1840 are flat with each other (instead of being generally adjacent to each other as in adjusting pulleys 1610 and 1710).Adjustable pulley portion members 1850a and 1850b may be engaged with slide blocks first and second 1860a and 1860b, respectively As shown in FIG 18B, the drive member end 1820 wraps around the base pulley portion, about a projection 1842a, on the adjustable pulley portion member 1850a, and is coupled to the first sliding block 1860a. Similarly, drive member end 1820' (or alternatively, a second drive member end 1820) wraps around the base pulley portion, about a projection 1842b, on the adjustable pulley portion member 1850b, and engages second slider block 1860b. The ends of the pusher member can be attached to slider blocks 1860a and 1860b using, for example, any of the attachment arrangements described herein, or any suitable attachment arrangement.

[0095] Similar to the adjustable pulley portion described above with respect to FIG. 17, members 1850a and 1850b can move parallel to the axis about which base pulley portion 1840 rotates. When first member 1850a moves in such an axial direction toward base pulley portion 1840, the interconnecting inclined surface (for eg, tilted, linearly tilted) of first member 1850a and first slider block 1860a may result in linear movement of first slider block 1860a in the recess away from projection 1842a, thereby stressing the end of drive member 1820. Similarly, when the second member 1850b moves in an axial direction toward the base pulley portion 1840, the inclined (eg, inclined, linearly inclined) surface of the second member 1850b and the second sliding block 1860b can be translated into a linear movement of the second sliding block 1860b in the recess away from the projection 1842b, thus tensioning the end of the drive member 1820'.

[0096] Members 1850a and 1850b may be moved independent of one another, which may allow independent tensioning of the drive member ends coupled to each member 1850a and 1850b. In addition, members 1850a and 1850b may move in tandem, which may allow simultaneous tensioning of the drive member ends coupled to members 1850a and 1850b. In some variations, during a tensioning process, the drive members can be moved back and forth (cyclically tightening and slightly loosening the drive members) to distribute the tension along the drive members.

[0097] When a desired level of tension in the drive member(s) is achieved with a particular axial position of the adjustable pulley portion relative to base pulley portion 1840, one or more of the fasteners 1870 may be set to lock the tension level. For example, the axial position of the fasteners 1870 can be fixed with a lock nut, threaded lock nut, etc.

[0098] The foregoing description, for purposes of explanation, uses specific nomenclature to provide a complete understanding of the invention. However, it will be apparent to one skilled in the art that no specific details are required to practice the invention. Therefore, the foregoing descriptions of specific embodiments of the invention are presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed; obviously, many modifications and variations are possible in view of the above teachings. The embodiments have been chosen and described for the purpose of better explaining the principles of the invention and their practical applications, thereby enabling others skilled in the art to better use the invention and various embodiments with various modifications as adapted to a particular use. contemplated. The following claims and their equivalents are intended to define the scope of the invention.

Claims (14)

Claims 1. A robotic surgical system comprising a pulley arrangement, the pulley arrangement comprising: a base pulley portion (1212, 1640) rotatable about an axis; an adjustable pulley part (1214, 1650) coupled to the base pulley part and movable in a first direction parallel to the axis; a first slider block (1660a) and a second slider block (1660b) each engaged with the adjustable pulley portion; Y a drive member (1220, 1220', 1620, 1620') coupled to the first and second slider blocks (1660a, 1660b), wherein the first and second slider blocks (1660a, 1660b) are arranged in an arcuate space in the pulley portion (1214, 1650) and engaged with the adjustable pulley portion (1214, 1650), wherein the first and second slider blocks (1660a, 1660b) are configured to move circumferentially toward each other in response to compression of the adjustable pulley portion (1214, 1650) against the base pulley portion (1212, 1640), thereby applying tension to the drive member (1220, 1220', 1620, 1620'). 2. The pulley arrangement of claim 1, wherein the drive member (1220, 1220', 1620, 1620') comprises a first end coupled to the first slider block (1660a, 1660b), at least a portion of the drive member (1220, 1220', 1620, 1620') wraps at least partially around the first slider block, and at least a portion of the drive member (1220, 1220', 1620, 1620') wraps at least partially around the portion adjustable pulley (1214, 1650). 3. The pulley arrangement of claim 1, wherein the adjustable pulley portion (1214, 1650) includes at least one sloped surface (1664) engaged with the first sliding block (1660a, 1660b), and wherein the inclined surface is a helical surface. 4. The pulley arrangement of claim 1, wherein the first slider block (1660a, 1660b) includes at least one sloped surface (1664). 5. The pulley arrangement of claim 1, wherein the first and second slider blocks (1660a, 1660b) are configured to move circumferentially toward each other at approximately equal speeds in response to compression of the adjustable pulley against the adjustable pulley. base. The pulley arrangement of claim 1, wherein the first and second slider blocks (1660a, 1660b) are disposed in an arcuate space defined at least in part by the adjustable pulley portion. 7. The pulley arrangement of claim 1, wherein the drive member (1220, 1220', 1620, 1620') is a first drive member comprising a first end coupled to the first sliding block and further comprising a second drive member comprising a second end coupled to the second sliding block. 8. The pulley arrangement of claim 1, wherein the drive element (1220, 1220', 1620, 1620') comprises a first end coupled to the first slide block and a second end coupled to the second slide block. 9. The pulley arrangement of claim 1, wherein the adjustable pulley portion (1710, 1810) comprises a first member (1750a, 1850a) engaged with the first sliding block (1760a, 1760a) and a second member (1750b , 1850b) coupled with the second slider block (1760b, 1860b), wherein the first and second members (1750a, 1750b, 1850a, 1850b) are movable in directions parallel to the axis. 10. The pulley arrangement of claim 1, wherein an axial position of the adjustable pulley portion relative to the base pulley portion is lockable, and wherein the axial position is lockable by one or more fasteners ( 1770, 1870). 11. The pulley arrangement of claim 1, wherein the adjustable pulley portion (1214, 1650) is adjacent to the base pulley portion (1212, 1640). 12. The pulley arrangement of claim 1, wherein the first slider block (1660a, 1660b) is configured to move i) in an arcuate path in response to compression of the adjustable pulley portion against the base pulley portion or ii) a linear path in response to compression of the adjustable pulley portion against the base pulley portion. The pulley arrangement according to claim 1, wherein the adjustable pulley portion (1214, 1650) is disposed in a recess in the base pulley portion. 14. The pulley arrangement of claim 1, further comprising a second pulley, wherein at least one drive member at least partially wraps the second pulley.