Fixture assembly for a double-acting cam

Abstract

A fixture comprising a body and a lock washer disposed between the body and a working surface, the washer having a plurality of circumferentially spaced cam surfaces, each of the plurality of circumferentially spaced cam surfaces being inclined with respect to a plane perpendicular to the central axis within the range of the cam radial angle, alternating with a plurality of circumferentially spaced slip surfaces in the circumferential direction about the central axis, each of the plurality of circumferentially spaced slip surfaces being inclined with respect to the plane within the range of the slip radial angle, each of the cam surfaces intersecting two adjacent slip surfaces at the radially raised portion and at the radially recessed portion, wherein the cam radial angle is greater than the slip radial angle, the radial angle ratio of the cam radial angle to the slip radial angle is about 4.5 or less, and the raised portion has a height of the raised portion with respect to the recessed portion of about 0.08 mm or more.

Description

Technical Field

[0001] The present invention generally relates to the field of fasteners, and more particularly to an improved fastener for use under vibration.

Background Art

[0002] U.S. Patent No. 5,080,545 is directed to a lock washer assembly having a wedge lock action, where two washers are used back-to-back, and one face of each washer is serrated to form a series of circumferentially extending cam surfaces, and these series of circumferentially extending cam surfaces function as a wedge lock device when disposed between a workpiece and a fastener element.

[0003] U.S. Patent No. 8,899,895 is directed to an anti-back-out fastener for use in high vibration applications. The fastener includes a nut having both a body having a wedge lock action fixing structure and a locking washer having a wedge lock action fixing structure that mates with the wedge lock action fixing structure of the body.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Means for Solving the Problems

[0005] By way of illustration only and not limitation, an elongated fixture body (20, 120) oriented about a rotational axis (16) is provided with parenthetical notations relative to corresponding parts, portions, or surfaces of the disclosed embodiments, the elongated fixture body comprising: a threaded section (21, 122) oriented about the rotational axis; a radially extending bearing portion (22, 122) operably configured to be axially retained by an operating surface (19) and having an inner head surface (23, 123), an outer head peripheral edge (24, 124), and an inner head peripheral edge (25, 125); and an annular locking washer (50, 150, 250) operably configured to move axially and rotationally relative to the bearing portion and to be disposed between the inner head surface of the bearing portion and the operating surface, the annular locking washer having an inner washer surface (53, 153, 253), an outer washer peripheral edge (54, 154, 254), an inner washer peripheral edge (55, 155, 255), and an outer washer surface (56, 156, 256), the inner washer surface comprising a plurality of circumferentially spaced washer cam surfaces (60, 160) radially extending between the inner washer peripheral edge and the outer washer peripheral edge, each of the washer cam surfaces being inclined with respect to a virtual plane (17) oriented perpendicular to the rotational axis from a lower washer cam edge (61, 161) to an upper washer cam edge (62, 162) within a range of washer cam - radial angles, the inner washer surface further comprising a plurality of circumferentially spaced washer slip surfaces (65, 165) radially extending between the inner washer peripheral edge and the outer washer peripheral edge, each of the washer slip surfaces being inclined with respect to a virtual plane oriented perpendicular to the rotational axis from a lower washer slip edge (66, 166) to an upper washer slip edge (67, 167) within a range of washer slip - radial angles (68), and a plurality of circumferentially spaced washer cam surfaces (60a, 60b, 160) alternating with a plurality of circumferentially spaced washer slip surfaces (65a, 65b, 65c, 165) in a circumferential direction about the rotational axis;At the radial washer projection (70a, 170) defined by the upper washer cam edge (62a, 162) of the washer cam surface (60a, 160) and the upper washer slip edge (67a, 167) of the first washer slip surface among two adjacent washer slip surfaces, and at the radial washer valley (71a, 171) defined by the lower washer cam edge (61a, 161) of the washer cam surface and the lower washer slip edge (66b, 166) of the second washer slip surface among two adjacent washer slip surfaces, it intersects two adjacent washer slip surfaces (65, 65b, 165); the washer cam radial angle is larger than the washer slip radial angle; the washer cam surface and the washer slip surface have a washer radial angle ratio (63 / 68) of about 4.5 or less between the washer cam radial angle and the washer slip radial angle; the radial washer projection is perpendicular to the virtual plane and has a projection height (72) of about 0.08 mm or more based on the radial washer valley, and an improved fixture assembly (15, 115) is provided which includes an annular locking washer (50, 150, 250).;

[0006] The inner head surface can comprise a plurality of circumferentially spaced head-cam surfaces (30, 130) extending radially between the inner head peripheral edge and the outer head peripheral edge; each of the head-cam surfaces can be inclined with respect to a virtual plane oriented perpendicular to the axis of rotation, within the range of the head-cam radial angle (33), from the lower head-cam edge (31, 131) to the upper head-cam edge (32, 132); the inner head surface can comprise a plurality of circumferentially spaced head-slip surfaces (35, 135) extending radially between the inner head peripheral edge and the outer head peripheral edge; each of the head-slip surfaces is inclined with respect to a virtual plane oriented perpendicular to the axis of rotation, within the range of the head-slip radial angle (38), from the lower head-slip edge (36, 136) to the upper head-slip edge (37, 137); the plurality of circumferentially spaced head-cam surfaces (30a, 30b, 130) alternate with the plurality of circumferentially spaced head-slip surfaces (35a, 35b, 35c, 135) in the circumferential direction about the axis of rotation; each of the head-cam surfaces (30a, 130) intersects two adjacent head-slip surfaces (35a, 35b, 135) at the radial head ridge (40a, 140) defined by the upper head-cam edge (32a, 132) of the head-cam surface and the upper head-slip edge (37a, 137) of the first head-slip surface of two adjacent head-slip surfaces, and at the radial head valley (41a, 141) defined by the lower head-cam edge (31a, 131) of the head-cam surface and the lower head-slip edge (36b, 136) of the second head-slip surface of two adjacent head-slip surfaces; the head-cam radial angle can be greater than the head-slip radial angle; the head-cam surface and the head-slip surface can have a head radial angle ratio (33 / 38) of the head-cam radial angle to the head-slip radial angle that is about 4.5 or less; the radial head ridge can have a ridge height (42) that is perpendicular to the virtual plane and is about 0.08 mm or more relative to the radial head valley. The washer-cam radial angle and the head-cam radial angle can be substantially equal.The washer slip radial angle and the head slip radial angle can be substantially equal.

[0007] The outer washer surfaces (56, 156, 256) can be provided with a plurality of circumferentially spaced first teeth (80, 180) configured to operate to resist rotation of the washer in a first rotational direction about an axis of rotation relative to the working surface under an applied axial load; the outer washer surfaces can be provided with a plurality of circumferentially spaced second teeth (85, 185) configured to operate to resist rotation of the washer in a second rotational direction about an axis of rotation relative to the working surface under an applied axial load. The plurality of circumferentially spaced first teeth can extend radially between the inner washer peripheral edge and the outer washer peripheral edge; the plurality of circumferentially spaced second teeth can extend radially between the inner washer peripheral edge and the outer washer peripheral edge.Each of the plurality of circumferentially spaced first teeth can include a first meshing edge surface (81, 181) oriented perpendicular to a virtual plane oriented perpendicular to the axis of rotation; each of the plurality of circumferentially spaced first teeth can include a first rear surface (82, 182) that is inclined within the range of a first rear radial angle (83) with respect to a virtual plane oriented perpendicular to the axis of rotation and that intersects the first meshing edge surface; each of the plurality of circumferentially spaced second teeth can include a second meshing edge surface (86, 186) oriented perpendicular to a virtual plane oriented perpendicular to the axis of rotation; each of the plurality of circumferentially spaced second teeth can include a second rear surface (87, 187) that is inclined within the range of a second rear radial angle (88) with respect to a virtual plane oriented perpendicular to the axis of rotation and that intersects the second meshing edge surface; the plurality of circumferentially spaced first teeth can alternate with the plurality of circumferentially spaced second teeth in the circumferential direction about the axis of rotation; each of the first rear surfaces (82, 182) of the plurality of circumferentially spaced first teeth can intersect adjacent second rear surfaces (87, 187) of the plurality of circumferentially spaced second teeth at a radially rear valley portion (90, 190); each of the first meshing edge surfaces (81, 181) of the plurality of circumferentially spaced first teeth can be separated from adjacent second meshing edge surfaces (86, 186) of the plurality of circumferentially spaced second teeth by a radially meshing valley surface (91, 191) within the range of an opposing meshing edge radial angle (92).

[0008] The fixture body can include a fixture nut (120) or a fixture bolt (20). The fixture body can be in the form of a bolt (20): a head portion (27) having an outer head surface and provided with an inner support portion (22); and a shank portion (21) axially extending from an inner head peripheral edge (25) of the inner support portion and configured to be operable to extend through an operating surface, and can include; the shank portion has a threaded section oriented around a rotation axis on the outside; an annular lock washer (50) is configured to be operable to receive the shank portion of the fixture body. The head portion of the bolt can include a hexagonal outer surface or a circular outer surface having an internal drive recess. The fixture body can be in the form of a nut (120); a head portion (127) having an outer head surface and provided with an inner support portion (122); and a washer holding portion (144) axially extending from an inner head peripheral edge (125) of the inner support portion, and can include; the head portion has a threaded section (121) oriented around a rotation axis on the inside: an annular lock washer (150) is configured to be operable to receive the washer holding portion of the fixture body. A portion of the washer holding portion can be crimped on a portion of an outer washer surface (156). The head portion of the nut can include a hexagonal outer surface or a circular outer surface having an internal drive recess.

[0009] The outer washer peripheral edge (254) of the annular lock washer (250) can be axially offset from the inner washer peripheral edge (255) of the annular lock washer (95), and the annular lock washer has a conical form before an axial load is applied. The threaded section of the fixture body can have a thread (28, 128) with a pitch angle (49), and each of the head cam surfaces can be operably configured to be in slidable contact with one of the washer cam surfaces on a contact plane (46) inclined at a contact angle (47) with respect to a virtual plane within an angular range (60) of relative rotational movement about the axis of rotation, and each contact angle can be greater than the pitch angle. The angular range of relative rotational movement about the axis of rotation can be substantially equal to the washer cam radial angle. The threaded section of the fixture body can have a thread with a pitch distance (29, 129), and the height of the radial washer protrusion can be less than the pitch distance.

[0010] The accompanying drawings are incorporated herein by reference as part of this specification. The drawings described herein illustrate embodiments of the subject matter disclosed herein and are explanatory diagrams of selected principles and teachings of the present disclosure. However, the drawings do not illustrate all possible implementations of the subject matter disclosed herein and are not intended to limit the scope of the present disclosure in any way.

Brief Description of the Drawings

[0011]

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DETAILED DESCRIPTION OF THE INVENTION

[0012] First, throughout the several drawings, like reference numerals are intended to consistently denote the same structural elements, parts, or surfaces, and thus, an element, part, or surface may be further described or explained by the entire specification in which it is described as an essential part thereof. It should be clearly understood that, unless otherwise specified, the drawings are to be read in conjunction with the specification (e.g., cross-hatching, component arrangement configuration, ratios, angles, etc.) and are intended to be considered as part of the overall description of the present invention. The terms "horizontal", "vertical", "left", "right", "upper", and "lower" as used in the following description, as well as their adjective and adverb derivatives (e.g., "horizontally", "to the right", "upward", etc.), simply refer to the orientation of the structure as shown when a particular figure is oriented towards the reader. Similarly, the terms "inner" and "outer" generally refer to the orientation of a surface with respect to its axis of elongation or axis of rotation, as required.

[0013] It will be understood that the specific assemblies and systems shown in the accompanying drawings and described in the following specification are merely exemplary embodiments of the concepts of the present invention as defined herein. Thus, specific dimensions, orientations, or other physical properties associated with the disclosed embodiments are not to be considered limiting unless otherwise specified. Further, like elements within the various embodiments described herein may, although not necessarily, generally be referred to using like reference numerals within this section of the specification.

[0014] It should be recognized that the teachings of the present invention are merely examples and not limiting. The concepts herein are not limited to use or application with a particular system or method. Thus, the means described herein are for purposes of explanation and are shown and described in connection with exemplary embodiments, but it will be recognized that the principles herein may equally apply to other types of systems and methods involving fixture assemblies.

[0015] As used herein, terms such as "first" and "second" do not necessarily indicate an order relationship, sequence relationship, or priority relationship, and are simply used to more clearly distinguish one element or set of elements from another element or set of elements, unless otherwise specified.

[0016] To the extent that the definitions presented above are consistent with the ordinary meaning, plain meaning, and customary meaning (especially as generally supported by dictionaries and / or technical glossaries), the above definitions are considered to be essentially supplementary. To the extent that the definitions presented above are inconsistent with the ordinary meaning, plain meaning, and customary meaning (especially as generally supported by dictionaries and / or technical glossaries), the above definitions shall prevail. If the definitions presented above are broader in scope than the ordinary meaning, plain meaning, and customary meaning in a certain aspect, then the above definitions shall prevail at least in that broader aspect.

[0017] Referring now to the drawings, there is provided an improved fixture assembly, generally designated 15, in which a first bolt type embodiment is shown. Fixture assembly 15 includes an elongated fixture body 20 oriented about a rotational axis 16 and an annular cam washer 50 oriented about rotational axis 16.

[0018] The fixture body 20 is shown as a horizontally elongated, specially configured tubular member oriented about the axis 16, and generally includes an upper tool-engaging hex head portion 27, an intermediate support portion 22, and a lower threaded shank portion 21. A washer 50 is rotatably and concentrically supported on the lower threaded shank portion 21.

[0019] The hex portion 27 is configured to be received within the driving surface of a corresponding hex socket, tool, or driving tool, such that a driving torque can be applied to the fixture body 20 about the axis 16. Alternatively, the head portion can have a circular outer surface with an internal driving recess or socket configured to receive the driving surface of a corresponding ratchet drive or driving tool, such that a driving torque can be applied to the fixture body 20 about the axis 16. Other drive configurations can be used as another alternative. As shown, the shank portion 21 is a solid cylindrical shaft oriented about the axis 16, and is externally threaded over a portion or all of its length such that it has a continuous helical thread 28 configured to engage the workpiece 18, and is to be installed on the workpiece 18 under the driving torque applied to the fixture body 20. The support portion 22 of the bolt fixture 20 extends radially from the head portion 27 about the axis 16, and its boundary is generally defined by an upward-facing annular surface 26, an outward-facing cylindrical surface 24, and a specially configured downward-facing annular surface or annular face 23. The specially configured downward-facing annular surface or annular face 23 is joined at its inner peripheral portion 25 to the upper peripheral end portion of the shank 21.

[0020] The annular surface 23 facing the lower side of the support portion 22 is adapted to face the wall surface 19 and to be axially held by the wall surface 19, and the cam washer 50 acts between the annular surface 23 facing the lower side and the wall surface 19. As shown, the annular surface 53 facing the upper side of the washer 50 is adapted to face the annular surface 23 facing the lower side of the fixture body 20 and to slidably engage with the annular surface 23 facing the lower side of the fixture body 20, and the annular surface 56 facing the lower side of the washer 50 is centered on the shank 21 of the fixture body 20 and directly adjacent to the shank 21 of the fixture body 20, and is adapted to face the outer working surface 19 of the workpiece 18 and to rotatably engage with the outer working surface 19 of the workpiece 18.

[0021] The cam washer 50 is disposed on the threaded shank 21 of the bolt 20, and the bolt 20 is fixed to the workpiece 18 via the thread 28. A wrench or other tool is used to tighten the fixture 20 in the clockwise direction via the hex head 27, thereby applying an axial load to the workpiece 18 via the support portion 22. To loosen the fixture 20 and relieve the axial load applied to the workpiece 18, the wrench or other tool is rotated in the opposite direction.

[0022] Figures 15 to 20 show the bolt 20. The annular surface 23 of the bearing portion 22 of the bolt 20 is specially configured to cooperate with the opposing face 53 of the washer 50 to provide improved cam functionality. As shown, the face 23 of the bearing portion 22 of the bolt 20 includes a plurality of circumferentially spaced cam surfaces, individually shown at 30, that extend radially at least partially between the inner edge 25 and the outer cylindrical surface 24 within the range of the cam radial angle 33. Each of the cam surfaces 30 is inclined with respect to a virtual plane 17 that is oriented perpendicular to the axis of rotation 16, from a lower cam edge 31 to an upper cam edge 32. The face 23 further includes a plurality of circumferentially spaced slip surfaces, individually shown at 35, that extend radially at least partially between the inner cylindrical edge 25 and the outer cylindrical surface 24 within the range of the slip radial angle 38. Each of the slip surfaces 35 is inclined with respect to the virtual plane 17, from a lower slip edge 36 to an upper slip edge 37. As shown, the plurality of circumferentially spaced cam surfaces 30 alternate with the plurality of circumferentially spaced slip surfaces 35 in the circumferential direction about the axis of rotation 16 and are inclined with respect to the plurality of circumferentially spaced slip surfaces 35, such that each cam surface 30 intersects two adjacent slip surfaces 35 at a radially extending ridge 40 that extends radially on one radial side and at a radially extending valley 41 that extends radially on the other radial side. As shown, the cam radial angle 33 is greater than the slip radial angle 38. In this embodiment, the radial angle ratio 33 / 38 of the cam radial angle 33 with respect to the slip radial angle 38 is about 4.5 or less and greater than about 1. As shown in Figure 20, in a plane perpendicular to the virtual plane 17, the radially extending ridge 40 has a height 42 with respect to the radially extending valley 41. In this embodiment, the height 42 is about 0.08 mm or more.

[0023] Therefore, referring particularly to FIGS. 18 to 20 as typical examples of the configuration of each alternating cam surface 30 and slip surface 35 that defines the face 23, the cam surface 30a extends radially within the cam - radial angle 33, at least partially between the inner circular edge 25 and the outer cylindrical surface 24 of the bearing portion 22 of the bolt 20. The cam surface 30a is inclined upward with respect to the virtual plane 17 from the lower cam edge 31a to the upper cam edge 32a. The left - hand slip surface 35b extends radially within the cam - radial angle 38, at least partially between the inner circular edge 25 and the outer cylindrical surface 24 of the bearing portion 22 of the bolt 20. The slip surface 35b is inclined downward with respect to the virtual plane 17 from the upper slip edge 37b to the lower slip edge 36b. The right - hand slip surface 35a extends radially within the cam - radial angle 38, at least partially between the inner circular edge 25 and the outer cylindrical surface 24 of the bearing portion 22 of the bolt 20. The slip surface 35a is inclined downward with respect to the virtual plane 17 from the upper slip edge 37a to the lower slip edge 36a. On one radial side, the cam surface 30a intersects the adjacent slip surface 35b at a radially extending valley 41 defined by the junction between the lower cam edge 31a of the cam surface 30a and the lower slip edge 36b of the left - hand slip surface 35b. On the other radial side, the cam surface 30a intersects the other adjacent slip surface 35a at a radially extending ridge 40 defined by the junction between the upper cam edge 32a of the cam surface 30a and the upper slip edge 37a of the right - hand slip surface 35a. As shown, the radially extending ridge 40 has a height 42 with respect to the radially extending valley 41.

[0024] Figures 5 to 14 show the cam washer 50. The washer 50 has a generally cylindrical configuration centered on the shaft 16, and its boundary is generally defined by an annular surface 53 facing upward, a cylindrical surface 54 facing outward, an annular surface 56 facing downward, and a cylindrical surface 55 facing inward. The cylindrical surface 55 facing inward defines the washer inner opening 51, through which the shank 21 is received. The annular lock washer 50 is operably configured to move axially and rotationally with respect to the bolt 20 and to be disposed between the inner head face 23 of the support portion 22 and the working surface 19.

[0025] The annular face 53 of the washer 50 is specially configured to cooperate with the opposing face 23 of the bearing portion 22 of the bolt 20 to provide improved cam functionality. As shown, the face 53 of the washer 50 includes a plurality of circumferentially spaced cam faces, individually shown at 60, that extend radially at least partially between the inner cylindrical surface 55 and the outer cylindrical surface 54 within the range of the cam radial angle 63. Each of the cam faces 60a - p is inclined with respect to a virtual radial plane 17 that is oriented perpendicular to the axis of rotation 16, from a lower cam edge 61a - p to an upper cam edge 62a - p. The face 53 further includes a plurality of circumferentially spaced slip faces, individually shown at 65, that extend radially at least partially between the inner cylindrical surface 55 and the outer cylindrical surface 54 within the range of the slip radial angle 68. Each of the slip faces 65a - p is inclined with respect to the virtual plane 17, from a lower slip edge 66a - p to an upper slip edge 67a - p. As shown, the plurality of circumferentially spaced cam faces 60a - p alternate with the plurality of circumferentially spaced slip faces 65a - p in the circumferential direction about the axis of rotation 16 and are inclined with respect to the plurality of circumferentially spaced slip faces 65a - p such that each cam face 60a - p intersects two adjacent slip faces 65a - p at a radially extending ridge 70 that extends radially on one radial side and at a radially extending valley 71 that extends radially on the other radial side. As shown, the cam radial angle 63 is greater than the slip radial angle 68. In this embodiment, the radial angle ratio 63 / 68 of the cam radial angle 63 with respect to the slip radial angle 68 is about 4.5 or less and greater than about 1. As shown in FIGS. 9 and 12, in a plane perpendicular to the virtual plane 17, the radially extending ridge 70 has a height 72 relative to the radially extending valley 71. In this embodiment, the height 72 is about 0.08 mm or more.

[0026] Accordingly, referring particularly to FIGS. 10 to 12 as typical examples of the configuration of each of the alternating cam surfaces 60a to p and slip surfaces 65a to p that define the face 53, the cam surface 60a extends radially at least partially between the inner cylindrical surface 55 and the outer cylindrical surface 54 of the washer 50 within the range of the cam radial angle 63. The cam surface 60a is inclined upward with respect to the virtual plane 17 from the lower cam edge 61a to the upper cam edge 62a. The left slip surface 65b extends radially at least partially between the inner cylindrical surface 55 and the outer cylindrical surface 54 of the washer 50 within the range of the cam radial angle 68. The slip surface 65b is inclined downward with respect to the virtual plane 17 from the upper slip edge 67b to the lower slip edge 66b. The right slip surface 65a extends radially at least partially between the inner cylindrical surface 55 and the outer cylindrical surface 54 of the washer 50 within the range of the cam radial angle 68. The slip surface 65a is inclined downward with respect to the virtual plane 17 from the upper slip edge 67a to the lower slip edge 66a. On one radial side, the cam surface 60a intersects the adjacent slip surface 65b at a valley portion 71 that extends radially and is defined by a joint between the lower cam edge 61a of the cam surface 60a and the lower slip edge 66b of the left slip surface 65b. On the other radial side, the cam surface 60a intersects the other adjacent slip surface 65a at a ridge portion 70 that extends radially and is defined by a joint between the upper cam edge 62a of the cam surface 60a and the upper slip edge 67a of the right slip surface 65a. As shown, the ridge portion 70 that extends radially has a height 72 with respect to the valley portion 71 that extends radially.

[0027] The face 56 of the washer 50 is further configured to cooperate with the opposing face 19 of the workpiece 18 to provide improved cam functionality. The face 56 of the washer 50 is configured to engage the working surface 19 of the workpiece 18 under a load applied around the face 56 of the washer 50 and has a plurality of equally circumferentially spaced and radially extending seizing teeth shown at 80 and 85 individually. As shown, the face 56 is operably configured to resist rotation of the washer 50 in a first rotational direction about the axis of rotation 16 with respect to the working surface 18 under an applied axial load, with a plurality of circumferentially spaced teeth 80, and is operably configured to resist rotation of the washer 50 in the opposite rotational direction about the axis of rotation 16 with respect to the working surface 18 under an applied axial load, with a plurality of circumferentially spaced teeth 85. Each of the teeth 80 and 85 extends radially between the inner cylindrical surface 55 and the outer cylindrical surface 54. Each of the circumferentially spaced teeth 80 comprises an engaging edge surface 81 oriented perpendicular to the virtual plane 17 and a rear surface 82 inclined within the range of the radial angle 83 with respect to the virtual plane 17 and intersecting the engaging edge surface 81. Each of the circumferentially spaced teeth 85 comprises an engaging edge surface 86 oriented perpendicular to the virtual plane 17 and a rear surface 87 inclined within the range of the radial angle 88 with respect to the virtual plane 17 and intersecting the engaging edge surface 86. Each of the rear surfaces 82 of the circumferentially spaced teeth 80 intersects the adjacent rear surface 87 of the circumferentially spaced teeth 85 at the radially rearward valley 90. Each of the edge surfaces 81 of the circumferentially spaced teeth 80 is separated from the adjacent engaging edge surface 86 of the circumferentially spaced teeth 85 by a planar edge valley surface 91 within the range of the opposing engaging edge radial angle 92. Thus, the engaging edge 81 faces in the first rotational direction about the axis 16, the engaging edge 86 faces in the opposite rotational direction, and the engaging edges 81 and 86 are on opposite sides of each other with the concave planar surface 91 in between.Therefore, the meshing edges 81 of the circumferentially spaced teeth 80 tend to mesh in the first rotational direction within the working surface 19 under the applied axial load and to resist the rotation of the washer 50 in this rotational direction with respect to the workpiece 18, and the meshing edges 86 of the circumferentially spaced teeth 85 tend to mesh in the opposite rotational direction within the working surface 19 under the applied axial load and to resist the rotation of the washer 50 in this opposite rotational direction with respect to the non-workpiece 18.

[0028] Therefore, the face 56 of the washer 50 includes a plurality of circumferentially spaced meshing surfaces, individually shown at 81, that extend radially between the inner cylindrical surface 55 and the outer cylindrical surface 54, and a plurality of circumferentially spaced rear surfaces, individually shown at 82, that extend radially between the inner cylindrical surface 55 and the outer cylindrical surface 54 within the range of the radial angle 83. Each of the rear surfaces 82 is inclined with respect to the virtual plane 17 from the rear valley portion 90 to the apex of the tooth 80 spaced circumferentially within the range of the radial angle 83. The face 56 further includes a plurality of circumferentially spaced meshing surfaces, individually shown at 86, that extend radially between the inner cylindrical surface 55 and the outer cylindrical surface 54, and a plurality of circumferentially spaced rear surfaces, individually shown at 87, that extend radially between the inner cylindrical surface 55 and the outer cylindrical surface 54 within the range of the radial angle 88. Each of the rear surfaces 87 is inclined with respect to the virtual plane 17 from the rear valley portion 90 to the apex of the tooth 85 spaced circumferentially within the range of the radial angle 88. The face 56 further includes a plurality of circumferentially spaced planar valleys, individually shown at 91, that extend radially between the inner cylindrical surface 55 and the outer cylindrical surface 54 within the range of the radial angle 92. Each of the surfaces 91 is, respectively, within the range of the radial angle 92, on a plane parallel to the virtual plane 17 from the meshing surface 81 to the opposing meshing surface 86. As shown, the plurality of circumferentially spaced rear surfaces 82 alternate with the plurality of circumferentially spaced rear surfaces 87 in the circumferential direction about the axis of rotation 16, and further, opposing pairs of rear surfaces 82 and 87 alternate with the plurality of circumferentially spaced planar surfaces 91 in the circumferential direction about the axis of rotation 16. As shown, the radial angles 82, 87, and 91 are generally equal.

[0029] The washer 50 has an upper cam face 53 facing the bolt - cam face 23. The washer 50 has a central opening 51 slidably installed on the shank 21. The opposing faces 56 of the washer 50 are substantially parallel to the cam face 53 and engage the working surface 19 of the workpiece 18 under the applied load. The opening 51 has a diameter that slidably accepts the diameter of the shank 21 but is less than the diameter of the bearing portion 22. The diameter of the opening 51 of the washer 50 is slightly larger than that of the shank 21, so that the opening 51 abuts against the portion 22 of the bolt 20. Thus, the washer 50 is movable towards the intermediate portion 22 to the engagement position, at which the cam element 60 on the washer 50 engages the cam element 30 on the bolt 20. In this position, the bolt 20 and the washer 50 can be rotated in opposite directions or integrally rotated in the same direction. The washer 50 is movable to the separation position, at which the cooperating cam elements 40 and 70 are separated from each other, so that the bolt 20 can be rotated about the axis 16 relative to the washer 50 and the non - machined workpiece 18. Each of the end faces 23 and 53 that function as cams comprises a plurality of circumferentially spaced cam faces 30 and 60 and a corresponding number of interconnected slip faces 35 and 65, respectively. In the configuration shown, each of the end faces 23 and 53 has 21 inclined cam faces 30 and 60 and an equal number of slip faces 35 and 65 inclined in opposite directions, respectively. More or fewer such faces may be used depending on the size of the washer and bolt.

[0030] When tightening the bolt 20, the bottom surface 56 of the washer 50 is frictionally fixed to the surface 19 of the associated workpiece 18 via the teeth 80. When the bolt 20 is further rotated, the slip surface 35 of the bolt 20 presses against the slip surface 65 of the washer 50 until the bolt 20 is fully tightened. When the bolt 20 is rotated in the loosening direction or counterclockwise direction by vibration or intentionally, the bottom surface 56 of the washer 50 maintains its frictionally fixed state to the surface 19 of the associated workpiece 18 via the teeth 85. During this time, the cam surface 30 of the bolt 20 slides upward on the cam surface 60 of the washer 50, and the bolt 20 moves to the wedge - lock position between the cam surface 60 of the washer 20 and the thread 28 on the shank 21 of the bolt 20. When the cam surface 30 of the bolt 20 slides upward on the corresponding cam surface 60 of the washer 50, the cam surface 30 of the bolt 20 is slidably in contact with the cam surface 60 of the washer 50 on a contact plane 46 inclined at a contact angle 47 with respect to a virtual radial plane 17 oriented perpendicular to the axis of rotation 16. The contact angle 47 is greater than the pitch angle 49 of the thread 28 on the shank 21 of the bolt 20. A locking action can also be achieved by the dimensions of the axial ridge heights 42 and 72 being smaller than the thread pitch distance 29 of the thread 28 on the shank 21 of the bolt 20.

[0031] Next, referring to FIGS. 22 - 26, a nut - type fixture assembly 115 according to a second exemplary embodiment is shown. The nut fixture assembly 115 is similar to the above - described bolt fixture assembly 15 with respect to the respective opposing cam surfaces 123 and 153 of the nut 120 and the washer 150, and the workpiece - engaging face 156 of the washer 150. The fixture assembly 115 broadly includes an elongated fixture body 120 oriented about the axis of rotation 16, and an annular cam washer 150 oriented about the axis of rotation 16.

[0032] The fixture body 120 is shown as a horizontally elongated, specially configured cylindrical member oriented about the axis 16, and generally includes an upper tool-engaging hex head portion 127, an intermediate support portion 122, and a lower washer-retaining portion 144 extending axially from the inner peripheral edge 125 of the support portion 122. In this nut embodiment, the head portion 127 of the nut fixture 120 includes an internally threaded hole 145 threaded internally over a portion or all of its axial length to provide an internally threaded section 121 oriented about the axis of rotation 16 and having an internal thread 128 with a female thread 128 configured to mate with a correspondingly sized threaded stud by applying a wrench or other tool to the hex head portion 127. In this embodiment, the outer axial portion of the washer-retaining portion 144 is radially crimped over the inner annular portion of the outer washer surface 156, thereby holding the washer 150 axially in a first direction while allowing the washer 150 to rotate about the axis 16 relative to the nut body 120 or move axially in a second direction.

[0033] The hex portion 127 is configured to be received within the drive face of a corresponding hex socket, tool, or drive tool, such that a drive torque can be applied to the nut 120 about the axis 16. The support portion 122 of the bolt fixture 120 extends radially from the head portion 127 about the axis 16 and is bounded by an upwardly facing annular surface or face 126, an outwardly facing cylindrical surface 124, and a specially configured downwardly facing annular surface or face 123, the specially configured downwardly facing annular surface or face 123 being joined at its inner peripheral edge 125 to the upper peripheral end of the tubular extension portion 144. The fixture 120 is adapted to be rotatably installed such that the face 156 abuts the surface 19 of the workpiece 18 to axially hold the nut 20 via a stud or other corresponding threaded member (not shown).

[0034] Similar to the bolt 20, the annular surface 123 of the bearing portion 122 of the nut 120 is specifically configured to cooperate with the opposing face 153 of the washer 150 to provide improved cam functionality. As shown, the face 113 of the bearing portion 122 of the nut 120 includes a plurality of circumferentially spaced cam surfaces individually shown at 130 that extend radially at least partially between the inner edge 125 and the outer cylindrical surface 124 within the range of the cam radial angle 33. Each of the cam surfaces is inclined with respect to the virtual radial plane 17 oriented perpendicular to the axis of rotation 16 from the lower cam edge 131 to the upper cam edge 132. The face 123 further includes a plurality of circumferentially spaced slip surfaces individually shown at 135 that extend radially at least partially between the inner cylindrical edge 125 and the outer cylindrical surface 124 within the range of the slip radial angle 38. Each of the slip surfaces 135 is inclined with respect to the virtual plane 17 from the lower slip edge 136 to the upper slip edge 137. As shown, the plurality of circumferentially spaced cam surfaces 130 alternate in the circumferential direction about the axis of rotation 16 with the plurality of circumferentially spaced slip surfaces 135 and are inclined with respect to the plurality of circumferentially spaced slip surfaces 135 such that each cam surface 130 intersects two adjacent slip surfaces 135 at the radially extending ridge 140 on one radial side and at the radially extending valley 141 on the other radial side. In a plane perpendicular to the virtual plane 17, the radially extending ridge 140 has a height of at least about 0.08 mm with respect to the radially extending valley 141.

[0035] Similar to washer 50, washer 150 has a generally cylindrical configuration centered on shaft 16, and is generally bounded by an upper-facing annular surface 153, an outer-facing cylindrical surface 154, a lower-facing annular surface 156, and an inner-facing cylindrical surface 155. The inner-facing cylindrical surface 155 defines an inner washer opening 151 through which the expansion portion 144 is received. The annular lock washer 150 is configured to be movable axially and rotationally relative to nut 120 and to be disposed between the inner head face 123 of support portion 122 and the working surface 19.

[0036] The annular face 153 of washer 150 is specifically configured to cooperate with the opposing face 123 of the support portion 122 of nut 120 to provide improved cam functionality. As shown, the face 153 of washer 150 includes a plurality of circumferentially spaced cam surfaces individually shown at 160 that extend radially at least partially between the inner cylindrical surface 155 and the outer cylindrical surface 154 and within the cam radial profile 63. Each of the cam surfaces 160 is inclined with respect to a virtual radial plane 17 that is oriented perpendicular to the axis of rotation 16 from a lower cam edge 161 to an upper cam edge 162. The face 153 further includes a plurality of circumferentially spaced slip surfaces individually shown at 165 that extend radially at least partially between the inner cylindrical surface 155 and the outer cylindrical surface 154 and within the slip radial angle 68. Each of the slip surfaces 165 is inclined with respect to the virtual plane 17 from a lower slip edge 166 to an upper slip edge 167. As shown, the plurality of circumferentially spaced cam surfaces 160 alternate with the plurality of circumferentially spaced slip surfaces 165 in the circumferential direction about the axis of rotation 16 and are inclined with respect to the plurality of circumferentially spaced slip surfaces 165 such that each cam surface 160 intersects two adjacent slip surfaces 165 at a radially extending ridge 170 that extends radially on one radial side and at a radially extending valley 171 that extends radially on the other radial side. In a plane perpendicular to the virtual plane 17, the radially extending ridge 170 has a height of at least about 0.08 mm relative to the radially extending valley 171.

[0037] The face 156 of the washer 150 is further configured to cooperate with the opposing face 19 of the workpiece 18 to provide improved cam functionality. The face 156 of the washer 150 has a plurality of equally circumferentially spaced and radially extending capture teeth shown at 180 and 185 respectively, configured to engage the working face 19 of the workpiece 18 under a load applied around the face 156 of the washer 150. As shown, the face 156 is operably configured to resist rotation of the washer 150 in a first rotational direction about the axis of rotation 16 relative to the working face 18 under an applied axial load, with a plurality of circumferentially spaced teeth 180, and is operably configured to resist rotation of the washer 150 in the opposite rotational direction about the axis of rotation 16 relative to the working face 18 under an applied load, with a plurality of circumferentially spaced teeth 185. Each of the teeth 180 and 185 extends radially between the inner cylindrical surface 155 and the outer cylindrical surface 154. Each of the circumferentially spaced teeth 180 comprises an engaging edge surface 181 oriented perpendicular to the virtual plane 17, and a rear surface 182 that intersects the engaging edge surface 181 and is inclined with respect to the virtual plane 17 within the range of the radial angle 83. Each of the circumferentially spaced teeth 185 comprises an engaging edge surface 186 oriented perpendicular to the virtual plane 17, and a rear surface 187 that intersects the engaging edge surface 186 and is inclined with respect to the virtual plane 17 within the range of the radial angle 88. Each of the rear surfaces 182 of the circumferentially spaced teeth 180 intersects an adjacent rear surface 187 of the circumferentially spaced teeth 185 at the radially rearward valley 190. Each of the edge surfaces 181 of the circumferentially spaced teeth 180 is separated from an adjacent engaging edge surface 186 of the circumferentially spaced teeth 185 by a planar edge valley surface 191 within the range of the opposite engaging edge radial angle 92. Thus, the engaging edge 181 faces in the first rotational direction about the axis 16, the engaging edge 186 faces in the opposite rotational direction, and the engaging edges 181 and 186 are on opposite sides of each other with the concave planar surface 191 therebetween.Accordingly, the meshing edges 181 of the teeth 180 spaced apart in the circumferential direction tend to mesh in the first rotational direction within the working surface 19 under the applied axial load and to resist the rotation of the washer 150 relative to the workpiece 18, and the meshing edges 186 of the teeth 185 spaced apart in the circumferential direction tend to mesh in the opposite rotational direction within the working surface 19 under the applied axial load and to resist the rotation of the washer 150 relative to the workpiece 18. Each of the rear surfaces 182 is inclined with respect to the virtual plane 17 within the range of the radial angle 83 from the rear valley 190 to the apex of the tooth 180 spaced apart in the circumferential direction, and each of the rear surfaces 187 is inclined with respect to the virtual plane 17 within the range of the radial angle 88 from the rear valley 190 to the apex of the tooth 185 spaced apart in the circumferential direction.

[0038] The washer 150 has an upper cam face 153 facing the nut-cam face 123. The washer 150 has a central opening 151 slidably mounted on the extension portion 144. The opposing faces 156 of the washer 150 are substantially parallel to the cam face 153 and engage the working surface 19 of the workpiece 18 under the applied load. The opening 151 has a diameter that slidably receives the diameter of the extension portion 144 but is less than the diameter of the support portion 122. The diameter of the opening 151 of the washer 150 is slightly larger than the extension portion 144, such that the opening 151 abuts against the portion 122 of the nut 120. Accordingly, the washer 150 is movable towards the intermediate portion 122 to the engagement position, at which the cam element 160 on the washer 150 engages the cam element 130 on the nut 120. At this position, the nut 120 and the washer 150 can be rotated in opposite directions or integrally rotated in the same direction. The washer 150 is movable to the separation position, at which the cooperating cam elements 140 and 170 are separated from each other, such that the nut 120 can be rotated relative to the washer 150 and the non-workpiece 18 about the axis 16. Each of the end faces 123 and 153 functioning as cams comprises a plurality of circumferentially spaced cam surfaces 130 and 160, respectively, and a corresponding number of interconnected slip surfaces 135 and 165.

[0039] When the nut 120 is tightened, the bottom surface 156 of the washer 150 is frictionally fixed to the surface 19 of the associated workpiece 18 via the teeth 180. When the nut 120 is further rotated, the slip surface 135 of the nut 120 presses against the slip surface 165 of the washer 150 until the nut 120 is fully tightened. When the nut 120 is rotated in the loosening direction or counterclockwise direction by vibration or intentionally, the cam surface 130 of the nut 120 slides upward against the cam surface 160 of the washer 150, and the nut 120 moves to the wedge - lock position between the cam surface 160 of the washer 120 and the thread 128 in the hole 145 of the nut 120. When the cam surface 130 of the nut 120 slides upward against the corresponding cam surface 160 of the washer 150, the cam surface 130 of the nut 120 is slidably in contact with the cam surface 160 of the washer 150 on a contact plane inclined at a contact angle 47 with respect to a virtual radial plane 17 oriented perpendicular to the axis of rotation 16. The contact angle 47 is greater than the pitch angle 49 of the thread 128 in the hole 145 of the nut 120. Further, since the dimension of the axial ridge height is smaller than the thread pitch distance of the thread 128 of the nut 120, the lock - action can be enhanced.

[0040] Next, referring to FIG. 27, a conical - type washer 250 according to a third exemplary embodiment is shown. The washer 250 is similar to the washer 50 described above with respect to the upper cam - face 253 and the lower workpiece - engaging face 256 of the washer 250. However, in this embodiment, the outer washer peripheral edge 254 of the washer 250 is axially offset downward from the inner washer peripheral edge 255 by an axial offset amount 95. As shown, due to the offset amount 95, the washer 250 has a conical form before a load is applied. When an axial load is applied by tightening the associated bolt 20 or nut 120 in the direction 275, the washer 250 tends to elastically deform and distort toward a flat non - conical form, thereby providing an additional internal locking stress force.

[0041] The form of the fixture assembly has been described and illustrated, and a number of modified forms have been considered. However, those skilled in the art will readily recognize that various additional modifications can be made. For example, the materials of construction are not considered essential and can be replaced or changed. For example, the workpiece 18 can be any metallic or non-metallic material and can be any member, sheet, or structure capable of fixing other members, sheets, or structures thereto.

[0042] Furthermore, it should be recognized that certain features of the systems described in the context of separate embodiments for clarity may also be provided in combination in a single embodiment. Conversely, various features described in the context of a single embodiment for brevity may also be provided separately or in any suitable combination. Although various embodiments have been described in detail above, it should be understood that the various embodiments are presented by way of example and not as limitations. It will be apparent to those skilled in the art that the disclosed subject matter can be embodied in other specific forms, variations, and modifications without departing from the scope, spirit, or essential nature of the invention. Accordingly, the above-described embodiments are to be considered in all respects as illustrative and not restrictive. The scope of the invention is indicated by the appended claims, and it is intended that all modifications within the meaning and scope of the equivalents thereof be included within the scope of the invention.

Claims

1. A fixture assembly body, An elongated fixture body oriented about a rotation axis, The fixture body having a threaded section oriented about the rotation axis, The fixture body having a radially extending support portion on the outside configured to be operable to be axially held by an operating surface, The support portion having an elongated fixture body having an inner head surface, an outer head peripheral edge, and an inner head peripheral edge; An annular locking washer configured to be operable to move axially and rotationally relative to the support portion and to be disposed between the inner head surface of the support portion and the operating surface, The annular locking washer having an inner washer surface, an outer washer peripheral edge, an inner washer peripheral edge, and an outer washer surface, The inner washer surface comprising a plurality of circumferentially spaced washer cam surfaces radially extending between the inner washer peripheral edge and the outer washer peripheral edge, Each of the washer cam surfaces being inclined with respect to a virtual plane oriented perpendicular to the rotation axis from a lower washer cam edge to an upper washer cam edge within a range of a washer cam radial angle, The inner washer surface comprising a plurality of circumferentially spaced washer slip surfaces radially extending between the inner washer peripheral edge and the outer washer peripheral edge, Each of the washer slip surfaces being inclined with respect to the virtual plane oriented perpendicular to the rotation axis from a lower washer slip edge to an upper washer slip edge within a range of a washer slip radial angle, The plurality of circumferentially spaced washer cam surfaces alternating with the plurality of circumferentially spaced washer slip surfaces in the circumferential direction about the rotation axis, Each of the washer cam surfaces intersecting the two adjacent washer slip surfaces at a radially extending washer ridge defined by the upper washer cam edge of the washer cam surface and the upper washer slip edge of a first washer slip surface of the two adjacent washer slip surfaces, and at a radially extending washer valley defined by the lower washer cam edge of the washer cam surface and the lower washer slip edge of a second washer slip surface of the two adjacent washer slip surfaces, The washer cam radial angle being greater than the washer slip radial angle, The washer cam surface and the washer slip surface have a washer radial angle ratio of the washer cam radial angle to the washer slip radial angle that is about 4.5 or less, an annular lock washer in which the radial washer ridge is perpendicular to the virtual plane and has a ridge height of about 0.08 mm or more based on the radial washer valley, a fixture assembly comprising the same.

2. The inner head surface includes a plurality of circumferentially spaced head cam surfaces extending radially between the inner head peripheral edge and the outer head peripheral edge, each of the head cam surfaces being inclined with respect to the virtual plane oriented perpendicular to the rotation axis from a lower head cam edge to an upper head cam edge within a range of the head cam radial angle, The inner head surface includes a plurality of circumferentially spaced head slip surfaces extending radially between the inner head peripheral edge and the outer head peripheral edge, each of the head slip surfaces being inclined with respect to the virtual plane oriented perpendicular to the rotation axis from a lower head slip edge to an upper head slip edge within a range of the head slip radial angle, the plurality of circumferentially spaced head cam surfaces being alternating with the plurality of circumferentially spaced head slip surfaces in the circumferential direction centered on the rotation axis, each of the head cam surfaces intersecting the two adjacent head slip surfaces at a radial head ridge defined by the upper head cam edge of the head cam surface and the upper head slip edge of the first head slip surface of the two adjacent head slip surfaces, and at a radial head valley defined by the lower head cam edge of the head cam surface and the lower head slip edge of the second head slip surface of the two adjacent head slip surfaces, the head cam radial angle being greater than the head slip radial angle, the head cam surface and the head slip surface having a head radial angle ratio of the head cam radial angle to the head slip radial angle that is about 4.5 or less, the fixture assembly according to claim 1, wherein the radial head ridge is perpendicular to the virtual plane and has a ridge height of about 0.08 mm or more based on the radial head valley.

3. The fixture assembly according to claim 2, wherein the washer cam radial angle and the head cam radial angle are substantially equal.

4. The fixture assembly according to claim 3, wherein the washer slip radial angle and the head slip radial angle are substantially equal.

5. The outer washer surface is provided with a plurality of circumferentially spaced first teeth configured to operate to resist rotation of the washer in a first rotational direction about the axis of rotation with respect to the working surface under an applied axial load, The outer washer surface is provided with a plurality of circumferentially spaced second teeth configured to operate to resist rotation of the washer in a second rotational direction about the axis of rotation with respect to the working surface under an applied axial load, the fixture assembly according to claim 1.

6. The plurality of circumferentially spaced first teeth extend radially between the inner washer peripheral edge and the outer washer peripheral edge, The plurality of circumferentially spaced second teeth extend radially between the inner washer peripheral edge and the outer washer peripheral edge, the fixture assembly according to claim 5.

7. Each of the plurality of circumferentially spaced first teeth has a first meshing edge surface oriented perpendicular to a virtual plane oriented perpendicular to the axis of rotation, Each of the plurality of circumferentially spaced first teeth has a first rear surface that is inclined with respect to the virtual plane oriented perpendicular to the axis of rotation within a range of a first rear radial angle and intersects the first meshing edge surface, Each of the plurality of circumferentially spaced second teeth has a second meshing edge surface oriented perpendicular to a virtual plane oriented perpendicular to the axis of rotation, Each of the plurality of circumferentially spaced second teeth has a second rear surface that is inclined with respect to the virtual plane oriented perpendicular to the axis of rotation within a range of a second rear radial angle and intersects the second meshing edge surface, The plurality of circumferentially spaced first teeth alternate with the plurality of circumferentially spaced second teeth in the circumferential direction about the axis of rotation, Each of the first rear surfaces of the plurality of circumferentially spaced first teeth intersects an adjacent second rear surface of the plurality of circumferentially spaced second teeth at a radially rearward valley portion, For each of the first meshing edge surfaces of the plurality of circumferentially spaced first teeth, within the range of the opposing meshing edge radial angles, each is separated from the adjacent second meshing edge surfaces of the plurality of circumferentially spaced second teeth by a radially meshing valley surface, the fixture assembly according to claim 6.

8. The fixture body is in the form of a bolt, a head portion having an outer head surface and comprising the inner support portion, a shank portion extending axially from the inner head peripheral edge of the inner support portion and configured to be operable to extend through the working surface, comprising, the shank portion comprising the threaded section oriented outwardly about the axis of rotation, the annular lock washer being configured to be operable to receive the shank portion of the fixture body, the fixture assembly according to claim 1.

9. The fixture body is in the form of a nut, a head portion having an outer head surface and comprising the inner support portion, a washer retaining portion extending axially from the inner head peripheral edge of the inner support portion, comprising, the head portion comprising the threaded section oriented inwardly about the axis of rotation, the annular lock washer being configured to be operable to receive the washer retaining portion of the fixture body, the fixture assembly according to claim 1.

10. A portion of the washer retaining portion is crimped onto a portion of the outer washer surface, the fixture assembly according to claim 9.

11. The outer washer peripheral edge of the annular lock washer is axially offset from the inner washer peripheral edge of the annular lock washer, and the annular lock washer has a conical form before an axial load is applied, the fixture assembly according to claim 1.

12. The threaded section of the fixture body has a thread with a pitch angle, each of the head cam surfaces is configured to be operable to be slidably in contact with one of the washer cam surfaces on a contact plane inclined at a contact angle with respect to the virtual plane within an angular range of relative rotational movement about the axis of rotation, each contact angle being greater than the pitch angle, the fixture assembly according to claim 2.

13. The angular range of relative rotational movement about the axis of rotation is substantially equal to the washer cam radial angle, the fixture assembly according to claim 12.

14. The fixture assembly according to claim 12, wherein the thread of the threaded section of the fixture body has a pitch distance, and the height of the raised portion of the radially seated washer is less than the pitch distance.

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