WO1990002272A2

WO1990002272A2 - Shaft positioning and coupling device

Info

Publication number: WO1990002272A2
Application number: PCT/US1989/003619
Authority: WO
Inventors: Bernard P. Gibson, Jr.; Howard C. Merchant
Original assignee: Moxee Innovations Corporation
Priority date: 1988-08-23
Filing date: 1989-08-22
Publication date: 1990-03-08
Also published as: WO1990002272A3; AU4214489A; CN1040665A

Abstract

A shaft coupling device has a resilient shaft locking ring (12) with a tapered surface (28) engaged by a corresponding surface (46a) on an outer ring (14) such that axial compression of the rings (12, 14) (e.g. involving screw threads (28, 56) co-axial with the device) causes the ring (12) to contact and grip the shaft (18) and may cause the ring (14) to expand into the bore of a machine element (71) (e.g. a Vee-pulley sheave).

Description

SHAFT POSITIONING AND COUPLING DEVICE

Technical Field

The present invention provides a device for coupling a machine element to a shaft. In particular, the device of the present invention is useful for securing the machine element axially along the shaft while distributing the coupling load around the circumference of the shaft and around the interior cylindrical bore or exterior cylindrical housing of the machine element. The device also acts to radially center the shaft with respect to the machine element. The shaft and the machine element are held in relative axial and concentric alignment. The invention utilizes the forces relating to friction resulting from thrust to couple a shaft and a machine element that surrounds the shaft for the purpose of transmitting mechanical forces commonly referred to as power transmission.

Background of the Invention The ability to transfer mechanical power or torque between sprockets, pulleys, bearings and shafts or other machine elements is accomplished by a wide variety of methods. Since the machine element must be coupled or attached to the shafting material in order to accommodate this transfer, common coupling means include, but are not limited to, set screws, keyways, or simple welding of the machine element to the shaft.

Set screws extending through the machine element and tightened against the shaft provide a point load for the coupling of the motions of the two components. If the set screws are not positioned symmetrically about the shaft, then the force of the screws against the shaft will cause the shaft axis to be misaligned relati to the machine element axis. The shaft will then be offset against one side of the machine element. Any misalignment caused by the set screw coupling will cause asymmetrical wear to the shaft and/or machine element. The set screws additionally may indent, score or bend the shaft. The use of a keyed component to couple the motion of a machine element and a shaft requires that the component include a mating key and keyway. In use, the rotational load is placed on the key. This method is subject to wearing and eventual failure of the keystock due to the forces applied thereto. Again, these are generally point or line loaded keyways that are subject to wear and the misalignment discussed above. The problem of axial alignment also arises if a number of machine elements are to be secured to the shaft and run simultaneously. Additionally, a machine element with a key along its inner bore would be mounted on a shaft having an axial keyway. The key and keyway then couple the rotation of the machine element with the rotation of the shaft. This keying method does not provide a means for securing the position of the machine element axially along the shaft.

Certain coupling methods described above are adjustable, i.e., the position of the machine element relative to the shaft can be adjusted. For example, set screws are releasable and, if the shaft is still functional, the axial position of the machine element is adjustable. If the shaft is welded to the machine element, the position of the machine element is not considered to be adjustable. In order to terminate such a coupling, it is likely that at least one of the components will be damaged sufficiently so as to lose its functional value. Other coupling devices utilize sets of conical hollow cylinders or rings inserted between the shaft and the machine element for coupling the motions of the two components. The rings include opposing wedged surfaces with gradual tapers. As the surfaces are drawn together, the rings are wedged between the components. In general, these devices require a substantial amount of torque in order to tighten the rings together and obtain an adequate locking of the coupler between the machine element and the shaft. Additionally, the devices generally require a number of components. The devices, shafts, and machine elements are often sized and designed for limited applications.

The coupling of the bearing with the shaft requires the rings to be expanded into the bearing easing causing a radially outward force to act against the bearing casing and thus against the bearing mechanism. This preloaded force can cause premature wear to the bearing mechanism and serious damage if a shaft misalignment occurs.

Machine components are sometimes coupled to shafts by the above-described devices by the coexistence of friction, force and the displacement of material. In overcoming the disadvantages of the various forces, including like and unlike material properties, coefficients of friction, variables in machining of surfaces, varying hardness of materials, material impurities, and grades of slopes, exactness of material and manufacture has given way to simplified design. By the use of tapered surfaces and an inordinate amount of force, enough coupler material may be displaced to create the desired frictional grip forces with or without the use of key ways or set screws. This material displacement may create a nonadjustable coupler which is not self -releasing and/or is not reusable. Additionally, the load distribution across the shaft and machine element may be difficult to control with this type of coupler. Thus, operation failure may result in damage to the shaft and/or machine element caused by the configuration and force of the coupler components.

It has been a generally accepted practice to couple sheaves, pulleys, bearings, enclosed gear units, etc., to a shaft by means of a split tapered bushing. These bushings provide overlapping tapered elements which cause the inner and outer elements to expand radially as these elements are forced in opposition to one another resulting in the frictional locking of the bushing to the outer surface of the respective shaft. The surfaces of the bushing material may be of common steel material or may be coated of some low friction material. As with other previous methods of locking machine components to shafting materials the shaft or the machine element must be maehined or selected by size as to the bushing. The bushings are expensive to machine and comprise a number of selective parts. Dependent upon the bushing design, installation and correct alignment may be difficult and time consuming. Most bushings allow for positive coupling of the machine element, the bushing and the shafting material but, generally, it has not been found that any of the designs allow for the unit to be operated to positively disengage the bushing from the machine part and the shafting material.

Other means of coupling machine elements to shafting material include, but are not limited to, splines, flats, pins, eccentric screws or surfaces, concentric surfaces, etc. All of the above experience to some degree the aforementioned difficulties. The present invention overcomes these and other problems in the prior art.

Summary of the Invention

The present invention provides apparatus and methods for coupling a shaft and a machine element such that the machine element is securely positioned axially and concentrically along the shaft. Certain embodiments of the invention additionally secure the machine element at a circumferential position relative to the shaft so that the rotational load between the shaft and machine element is transferred through the coupler. The coupler of the present invention contracts about and grips the shaft at the desired position. Simultaneously, the coupler contracts about or expands into the machine element, depending on the machine element configuration, or is keyed to the machine element. The rotational load of the shaft is thus transferred through the coupler to the machine element.

In accordance with the present invention, the coupler includes a resilient shaft lock, a lock ring, and a lock nut. The shaft lock includes a cylindrical interior surface. The diameter of the interior surface is within a range of diameters relative to the shaft diameter. The diameter range depends on material characteristics, component size, desired tightening torque, etc. This range is referred to as the "corresponding range." The shaft lock also includes an exterior surface that has an extended end and a tapered load sur ace extending away and radially outwardly from the extended end. The lock ring has a cylindrical exterior surface diameter that falls within the corresponding range to the diameter of the bore of a machine element. The lock ring also includes an interior surface that has first and second wedged surfaces that extend away and radially outwardly from a centerline. The lock nut has an interior surface diameter that falls within the corresponding range of the shaft lock extended end diameter. The lock nut also includes an exterior surface that has a load surf ce. The wedged surfaces of the lock ring form angles that inversely correspond to the angles of the load surfaces of the shaft lock and the lock nut. When the lock ring is positioned over the shaft lock between the load surface of the shaft lock and the load surface of the lock nut, the axial displacement of the shaft lock relative to the lock ring causes the load surfaces to bear against the wedged surfaces thereby causing the lock ring to radially expand. Simultaneously, the loek nut radially contracts about the shaft lock and the shaft lock in turn radially contracts due to the force of the lock ring and the lock nut.

When the lock nut is axially displaced away from the shaft lock load surface, the load surfaces move from under the loek ring and allow the lock ring to contract. Simultaneously, the lock nut and shaft lock expand. In this manner, the coupler, mounted between a shaft and a machine element having a center bore, adjustably couples the rotational load of the shaft and machine element.

In accordance with still further aspects of the present invention, the extended end of the shaft lock and the interior surface of the lock ring are correspondingly threaded. The lock ring is tightened over the extended end, thereby drawing the load surfaces toward one another and against the wedged surface of the lock ring. Alternatively, the coupler further includes a tightening nut which is threadably mountable over the extended end such that the lock ring and lock nut are positioned between the tapered load surfaces of the shaft lock and the tightening nut. As the tightening nut is tightened over the shaft lock, it forces the lock nut toward the shaft lock load surface to produce the coupling effect described above.

■ In accordance with still further aspects of the present invention, an internal bearing coupler includes a resilient lock ring and shaft lock. The coupler is used to secure the axial and circumferential position of a machine casing to a shaft. The machine casing may have a splined interior surface or keyway. This method of coupling increases the mechanical force carrying capabilities of the casing and shaft, and secures the shaft within the machine element. The lock ring includes an interior surface, an exterior surface, and a tooth. The interior surface includes a wedged surface and a threaded surface, the wedged surface extending radially outwardly from the threaded surface. The diameter of the exterior surface of the lock ring falls within the corresponding diameter machine casing interior surface. The lock ring is inserted into the casing and the rotational position of the lock ring relative to the shaft lock is secured by the tooth mating with the spline or keyway of the casing. The shaft lock includes a cylindrical interior surface, the diameter of which falls within the corresponding diameter of the shaft. The shaft lock also includes an exterior surface which has a threaded end. The threads correspond to the threaded surface of the lock ring. A tapered load surface extends away and radially outwardly from the threaded end. The load surface forms an angle that inversely corresponds to the angle of the wedged surface of the lock ring. The tightening of the shaft lock into the lock ring causes the load surface to be drawn toward and contact the wedged surface thereby causing the lock ring to expand and causing the shaft lock to contract. As the shaft lock is loosened from the lock ring, and the load surface moves away from the wedged surface, the lock ring contracts and the shaft locks expand to their original configurations. In this manner, the coupler, mounted between a shaft and a machine casing, adjustably couples the rotational load of the shaft and bearing casing.

In accordance with additional aspects of the present invention, a coupler is provided for positioning a machine element axially along a shaft. The coupler includes an open-ended shaft casing, an axial positioning component, a keying component, and a resilient shaft lock. The shaft casing has a cylindrical interior surface. Near one open end, the interior surface includes a first surface, the diameter of which is greater than the diameter of the shaft, and a wedged surface which extends radially outwardly from the first surface to the open end. The shaft casing has a cylindrical exterior surface with a diameter within the corresponding range of the machine element bore. The resilient shaft lock includes a cylindrical interior surface with a diameter within the corresponding range of the shaft diameter, and an exterior surface having a tapered load surface and a first end. The tapered load surface forms an angle that inversely corresponds to the angle of the wedged surface. The first end has a diameter within the corresponding range of the diameter of the shaft casing first surface and is positionable such that the load surface is adjacent the wedged surface. The keying component secures the circumferential position of the shaft casing relative to the shaft lock.

The axial displacement of the shaft lock into the shaft casing causes the load surface to be drawn toward and against the wedged surface, thereby causing the shaft lock to contract. Correspondingly, as the shaft loek is loosened from within the shaft casing, the load surface moves away from the wedged surface thereby allowing the shaft lock to expand to its original configuration. In this manner, the coupler, mounted between a shaft and a machine element, fixes the position of the shaft casing, and, thus, the machine element, axially and circumferentially along the shaft. In accordance with still further aspects of the present invention, an external bearing coupler couples a machine element having an exterior cylindrical surface to a shaft having a cylindrical surface. The coupler includes a resilient lock ring, and a load ring. The lock ring has a cylindrical interior surface and a cylindrical exterior surface. The interior surface includes a machine element contact surface with a diameter within the corresponding range of the diameter of the machine element exterior surface, a shaft contact surface with a diameter within the corresponding range of the shaft, and an intermediate surface between the two contact surfaces. The lock ring exterior surface has a first surface that circumscribes a portion of the machine element contact surface, and a tapered load surface extending radially inwardly from the first surface and circumscribing the intermediate surface. The load ring is slidably mountable over the lock ring and has a cylindrical exterior surface and a cylindrical interior surface. The interior sur ace has a first end with a diameter within the corresponding range of the diameter of the lock ring first surface, and a load shoulder spaced from the first end such that the load shoulder contacts the tapered load surface. As the load ring is axially displaced over the lock ring, the load shoulder contacts the load surface and causes the lock ring to contract. In this manner, the lock ring contracts about and grips the machine element and shaft. The rotational load of the machine element and shaft is thus adjustably coupled.

The present invention provides an economical and efficient coupler that allows for easy repositioning of a machine element along a shaft. The coupler is nondestructive so that the functional integrity of the machine element and the shaft are retained through the coupling process. The coupler minimizes the amount of torque necessary to secure the machine element and shaft together.

Forces induced by nonaxial and/or nonconcentric alignment are reduced, thereby increasing the expected lives of the components. Since the device does not displace material but instead displaces either a locking ring or else allow for the elasticity of material coupled with the spring capabilities of certain materials, the invention is a significant development in the accepted state of the art. Finally, the present invention provides a coupler that is suitable for use with a range of shaft diameters. Brief Description of the Drawings

The foregoing objects and many other advantages of the invention will become more readily appreciated as the same become better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein: FIGURE 1 is an exploded isometric view of one embodiment of the coupler of the present invention;

FIGURE 2 is a side view of an assembled coupler, with the coupler being cut¬ away by a plane defined by the through slit of the shaft lock component;

FIGURE 3 is a bushing for sizing the shaft lock to fit the shaft in accordance with the present invention;

FIGURE 4 is a side cut-away view of an assembled coupler including a bushing for sizing the shaft lock in accordance with the present invention;

FIGURE 5 is a side view of an alternative embodiment of a coupler in accordance with the present invention, with the coupler being cut-away by a plane defined by the through slit of the shaft lock component;

FIGURE 6 is an exploded isometric view of an internal bearing coupler in accordance with the present invention suitable for coupling a bearing-type casing at a specific position along a shaft;

FIGURE 7 is a partially cut-away side view of the assembled coupler illustrated in FIGURE 6;

FIGURE 8 is an exploded isometric view of an external bearing coupler in accordance with the present invention suitable for coupling a bearing-type casing at a specific position along a sha t; FIGURE 9 is a partially cut-away side view of the assembled bearing coupler illustrated in FIGURE 10.

FIGURE 10 is an exploded isometric view of a multisheave coupler in accordance with the present invention; FIGURE 11 is a side cut-away view of an assembled multisheave coupler, the coupler being cut-away by a plane defined by the axial keyway of the shaft; and

FIGURE 12 is a side cut-away view of an alternative multisheave coupler, the coupler being cut-away by a plane defined by the axial keyway of the shaft. Description of Preferred Embodiments of the Invention The present invention is directed to an adjustable coupler suitable for coupling a shaft and a machine element so that the position of the machine element axially along the shaft is secured. Certain embodiments of the coupler additionally secure the circumferential position of the machine element relative to the shaft so that the coupler transfers the rotational load between the shaft and machine element. The eoupler operates by circumferentially gripping the shaft surface while simultaneously circumferentially gripping a bore through the machine element or an outer casing surface of the machine element.

Machine elements that may be coupled to a shaft include, but are not limited to, sheaves, pulleys, fans, sprockets^', bearing housings, speed reducers, and hubs. Certain embodiments of the coupler of the present invention are suitable for coupling two sha ts together. For ease of discussion, the couplers and coupling functions will be described generally in terms of coupling a shaft and a sheave or a shaft and a bearing element. It is to be understood that the couplers are not meant to be limited to use with these particular machine elements. With reference to FIGURE 1, one preferred embodiment of the coupler 10 includes a shaft lock 12, a lock ring 14, and lock nut 16. The sha t lock, lock ring, and lock nut interact to secure a machine element such as a sheave (not shown) at a specific axial position along shaft 18 while simultaneously securing the sheave circumferentially relative to the shaft. Shaft lock 12 is compressed about the shaft surface thereby decreasing the effective diameter of the shaft lock interior surface that grips the shaft. Lock ring 14, in turn, is expanded into the sheave hub thereby increasing the effective diameter of its exterior surface which grips the hub. Coupler 10 thus transfers the load between the shaft and the sheave.

Shaft lock 12 includes interior surface 22 and exterior surface 24. Interior surface 22 is cylindrical and is preferably finely circumferentially knurled to provide a high friction shaft contact surface. Exterior surface 24 includes threaded end 26, tapered load surface 28, and flanged head 30. Tapered load surface 28 extends from the threaded end radially outwardly toward the flanged head. Tapered load surface 28 terminates at shoulder 34 of flanged head 30. It has been found that a taper in the range of 20-30° relative to the interior surface is a desirable taper. The steepness of the taper controls the torque and the necessary travel required to tighten the coupler and to achieve an adequate connection between the shaft and the machine element.

Wrench holes 36 extend longitudinally into the side of flanged head 30 opposite the shoulder 34. The holes are suitable for receiving a tightening device such as a spanner wrench. The tightening device is used to adjust the circumferential position of shaft lock 12 relative to shaft 18.

Shaft lock 12 preferably includes through slit 38 and compression slits 40. Through slit 38 extends from the exterior to the interior surface. Compression slits 40 extend from the exterior to interior surface and from flanged head 30 to near threaded end 26. Through slit 38 and compression slits 40 enable interior surface 22 to be contracted and expanded. Preferably, through slit 38 is not parallel to the axis of shaft 18. The slit angle allows the threads on the component to be slightly misaligned and still function. For example, as the diameter of the threaded surface decreases, threads across the slit will become misaligned. The threads may become so misaligned that the teeth on one side of through slit 38 are aligned with the grooves on the other side so that the surface being tightened over the threaded end is locked. By angling through slit 38, as shaft lock 12 contracts, the slit angle offsets the tooth misalignment caused by the contracting of shaft lock. Alternatively, flat threads are used for at least one of the threaded surfaces. These threads provide the same antilocking characteristic as the angled through slit due to the ability of the threads to pass one another across the slit even if the threads across the slit are not perfectly aligned.

Lock ring 14 includes interior surface 42 and exterior surface 44. Exterior surface 44 is cylindrical. Interior surface 42 includes wedged surfaces 46(a) and 46(b), and centerline 48. Lock ring 14 is symmetrical about centerline 48. Wedged surfaces 46 extend radially outwardly and away from the centerline.

Lock ring 14 preferably includes through slit 52 and expansion slits 54.

Through slit 52 extends from exterior surface 44 to interior surface 42. Expansion slits 54 extend from exterior surface 44 to interior surface 42 and axially through wedged surfaces 46 terminating at or before centeriine 48. The slits allow the lock ring to be radially expanded and contracted. Lock nut 16 includes threaded interior surface 56 and exterior surface 58. Threaded interior surface 56 corresponds to threaded end 26 of shaft lock 12 such that lock nut 16 is threadably engageable with the shaft lock. Exterior sur ace 58 includes tapered load surface 60, flanged head 62, wrench holes 63, and shoulder 64. Wrench holes 63 extend longitudinally into flanged head 62 on the side of the flanged head opposite shoulder 64. The holes are suitable for receiving a tightening device such as a spanner wrench. The tightening device is used to adjust the circumferential position of lock nut 16 relative to shaft 18.

Tapered load surface 60 extends radially outwardly toward flanged head 62 and terminates at shoulder 64. The angle of tapered load surface 60 is the same as the angle of tapered load surface 28. The angles of wedged surfaces 46(a) and 46(b) inversely correspond to the angles of tapered load surfaces 28 and 60, respectively. The interior surface of lock ring 14 thus mates with the shaft lock and lock nut load surfaces.

Preferably, lock nut 16 includes through slit 68 and compression slits 70. Through slit 68 extends from the exterior to the interior surface. Compression slits 70 extend the length of the loek nut and from exterior surface 58 terminating close to threaded interior surface 56. The slits allow the lock nut to be expanded and contracted.

With reference to FIGURE 2, in order to lock sheave 71 at a specific axial and circumferential position along shaft 18, shaft lock 12 is positioned axially along the shaft. Lock ring 14 is positioned circumferentially about shaft lock 12 so that wedged surface 46(a) is adjacent tapered load surface 28. The axial relationship of shaft lock 12 and lock ring 14 is adjusted so that the lock ring is centered over the position on the shaft at which the machine element is to be centered. Sheave 71 is then centered over exterior surface 44 of lock ring 14 and the sheave mounted thereover. Finally, lock nut 16 is threaded onto threaded end 26 of shaft lock 12. During the coupling and uncoupling process, flanged heads 30 and 62 aid in securing the sheave in the desired position relative to the lock ring. Tightening devices are utilized to control the rotational position of the components about the shaft.

As lock nut 16 is tightened over shaft lock 12, tapered load surface 60 is drawn towards tapered load surface 28. As the surfaces are drawn together, they contact wedged surfaces 46(a) and 46(b). The load surfaces act against the wedged surfaces and force the lock ring to expand radially outwardly into the sheave hub. Simultaneously, the resistance of the lock ring, and subsequent resistance of the sheave, act against the tapered load surfaces to force the shaft lock and lock nut to contract against the shaft. The radially inward force on lock nut 16 is transferred to threaded end 26 of shaft lock 12 so that the inward force is distributed relatively uniformly over the length and circumference of the shaft lock. The coupler is tightened so that shaft lock 12 grips shaft 18 and the rotation of the shaft is transferred to the coupler. Lock ring 14 is expanded into the sheave so that the rotation of the coupler, in turn, is transferred to the sheave.

Preferably, a resilient material with low material flow characteristics is used to make the shaft lock, loek ring, and lock nut. By utilizing resilient material and/or the through and compression slits described above, with the above-described configuration, the coupler is self -releasing. When lock nut 16 is backed off of shaft lock 12, tapered load surfaces 28 and 60 move away from one another and thus the outward pressure against lock ring 14 is reduced. As the pressure against lock ring 14 is reduced, the lock ring contracts to its original shape, thereby releasing the sheave. As the lock nut and shaft lock move away from one another and slide out from under the wedged surfaces, the pressure from the lock ring decreases, and the lock nut and shaft loek expand to their original shapes, thereby releasing the shaft.

The component materials are chosen to be compatible with the specific application. For example, the threaded surfaces of shaft lock and lock ring may be highly resilient compared to the material making up the flanged heads. In this manner, each component part is made up of the material most compatible with the part's function. Suitable coupler materials include metals, polymer-type materials, and certain ceramics. Coupler components made up of composite or multilayer materials, such as components with sleeves, plates, treated surfaces, and inserts, are also suitable. For example, the components may be knurled, splined, anodized, electroplated, or painted.

Other considerations for suitable materials for the coupler include the coefficient of friction characteristics between the shaft, the coupler components, and the sheave. It is preferable that the lock ring interior surface, and the shaft lock and lock nut exterior surfaces have relatively low friction characteristics so that the sur aces slide easily against each other when the coupler is tightened or loosened. Additionally, it is preferable that the contact between the coupler surfaces and the shaft and the sheave be subject to relatively high friction to aid in the gripping function of the coupler. These characteristics affect the torque and travel required to tighten the coupler. For example, by finishing the interactive component surfaces to a specific high-micron finish, the tightening torques and tapers may be decreased. The high-micron finish is achieved by the application of certain additives or. greases, particularly molybdenum additives, or by coating the surfaces with bonding agents having low coefficients of friction. The foregoing material considerations apply to the additional embodiments of the invention described below.

With reference to FIGURE 3, a series of split bushings 72 are used to adjust the inner diameter of shaft loek 12 for use with a variety of shaft diameters. Each split bushing includes outer surface 73 with a partial split 74, and a knurled inner surface 75. The thicknesses of split bushings 72 determine the range of shaft diameters with which a coupler using the bushings is functional. The circumference of outer surface 73 is slightly less than one-half the circumference of interior surface 22 of shaft lock 12. Split bushings 72 fit between a shaft and shaft lock 12 with adequate space between them to allow them to contract around the shaft. With reference to FIGURE 4, split bushings 72 it within interior surface 22 of shaft lock 12. Shaft 18 slides between the bushings. As the coupler is tightened, as described above, interior surface 22 of shaft lock 12 contracts against split bushings 72. Split bushings 72 contract and inner surfaces 75 grip the surface of shaft 18. Partial splits 74 and the circumferential dimensions of the split bushings allow the split bushing pair to contract about the shaft, thereby transferring the clamping force from the coupler components. The length of the split bushings is preferably equal to the length of the shaft lock to provide an even and complete distribution of the force from shaft lock 12 to split bushings 72.

With reference to FIGURE 5, coupler 76 includes tightening nut 77, shaft lock 78, lock nut 79 and lock ring 80. Shaft lock 78 and lock ring 80 are similar to shaft loek 12 and lock ring 14, respectively. Lock nut 79 is similar to lock nut 16 except that the interior surface 81 of lock nut 79 is not threaded. To couple shaft 18 and sheave 71, shaft lock 78, lock ring 80, and lock nut 79 are assembled between the shaft and sheave as described above. Tightening nut 77 is threaded onto threaded end 82 of shaft lock 78 which extends axially beyond lock nut 79. As tightening nut 77 is tightened, the tapered load surfaces of the shaft lock and lock nut are forced together and the coupling takes place as described above.

An alternative preferred embodiment of the coupler of the present invention secures a shaft to a bearing-type machine element. With reference to FIGURE 6, internal bearing coupler 83 couples unkeyed shaft 84 to splined bearing casing 85. Shaft 84 is coupled to bearing casing 85 by distributing the load circumferentially about the shaft and within the bearing casing. Bearing casing 85 has entry interior 86 and main cavity 87 divided by shoulder 88. Main cavity 87 includes spline or keyway 89.

Coupler 83 includes shaft lock 90 and lock ring 91. Shaft lock 90 is similar to shaft lock 12. Shaft lock 90 includes interior surface 92, and exterior surface 93. Interior surface 92 is preferably knurled circumferentially to provide a high friction contact between shaft lock 90 and shaft 84. Exterior surface 93 includes threaded end 94, tapered load surface 95, and flanged head 96. The angle of the tapered load surface is preferably in the range of 20-30°, as measured from the interior surface. Through slit 97 in the shaft lock extends from the exterior to the interior surface. Compression slits 98 extend from the exterior surface to the interior surface and from flanged head 96 terminating near threaded end 94. Flanged head 96 includes wrench holes 99. These are similar to wrench holes 36 and 63 in coupler 10.

Lock ring 91 includes exterior surface 100 and interior surface 101. Interior surface 101 includes threaded surface 102, wedged surface 104, tooth 106, and through slit 107. Threaded surface 102 corresponds to threaded end 94 so that lock ring 91 is threadably engageable with shaft lock 90. The angles of load surface 95 and wedged surface 104 inversely correspond. Tooth 106 extends axially away from exterior surface 100 adjacent threaded surface 102. Tooth 106 is sized and is positioned along the edge of lock ring 91 so as to fit within spline 89 when lock ring 91 is positioned within entry interior 86. The tooth configuration corresponds to the characteristics of spline 89. Through slit 107 in lock ring 91 is preferably positioned opposite tooth 106.

With reference to FIGURE 7, to secure shaft 84 within the bearing casing 85, two couplers are utilized. One coupler 83 will be described with the understanding that a second coupler is similarly positioned on the other side of bearing casing 85. Lock ring 91 is inserted into bearing casing 85 until the ring abuts shoulder 88. Tooth 106 is inserted into spline 89. Shaft 84, with shaft lock 90 mounted thereon, fits into bearing casing 89 through lock ring 91. The axial position of shaft 84 relative to bearing casing 85 is adjusted to the desired position. Shaft lock 90 is then threaded into lock ring 91. Shaft lock 90 is tightened within lock ring 91, while the rotation of the lock ring is prevented by the catching of tooth 106 in spline 89. Shaft lock 90 is drawn into lock ring 91, thereby causing tapered load surface 95 to contact wedged surface 104. As load surface 95 is axially displaced, wedged surface 104 and, thus, lock ring 91, is forced radially outwardly. In turn, load surface 95 and shaft lock 90 are forced radially inwardly. The lock ring exterior surface expands into and grips entry interior 86. Simultaneously, the interior surface of the shaft lock contracts about and grips the shaft. In this manner, the shaft is radially centered within the machine element.

Tooth 106 acts to prevent the rotation of lock ring 91 within the casing as shaft lock 90 is tightened therein, i.e., the tooth bears the tightening load. Once the coupler is tightened, the rotational load of bearing easing 85 is carried by the bearing casing surface that contacts the lock ring exterior surface.

Coupler 83 is also suitable for use with a bearing casing and shaft that are sized so that the coupler fits between the main cavity and the shaft without the need for a separate entry interior. Tooth 106 would then extend radially, slightly beyond the exterior surface of lock ring 91 in order to carry the tightening load on the lock ring. In other instances, the main cavity is machined to form an entry interior to accommodate the coupler.

An alternative internal bearing coupler utilizes an extended lock ring which is similar to lock ring 14 of coupler 10. The extended lock ring is as long as the bearing casing with which it is used. Thus, rather than using two couplers with shaft lock and lock ring components, a single lock ring and two shaft locks are used to secure the shaft within the bearing.

With reference to FIGURE 8, external bearing coupler 120 secures bearing casing 122 to shaft 124. Coupler 120 is especially useful with bearing casings which do not include an internal keyway and in situations where it is not desirable to machine a keyway or an entry interior in the bearing casing. The coupler includes lock ring 126 and load ring 128. Lock ring 126 includes interior surface 130 and exterior surface 132. Interior surface 130 includes casing contact surface 134, intermediate surface 136, and shaft contact surface 138. Shoulder 140 is formed between intermediate surface 136 and shaft contact surface 138. Exterior surface 132 includes threaded end 144, wedged surface 146, and shaft end 148. Wedged surface 146 extends from threaded end 144 radially inwardly to shaft end 148. Shaft end 148 includes wrench holes 150 which are suitable for receiving the ends of a tightening device. The tightening device is used to control the circumferential position of the lock ring relative to the load ring.

Lock ring 126 is split from the exterior to interior surface by through slit 152. Compression slits 154 run from the shaft end to near shoulder 140 and from interior surface 130 terminating before exterior surface 132. Compression slits 154 allow the shaft end of lock ring 126 to be compressed about shaft 124. Compression slits 156 run from threaded end 144 to wedged surface 146 and from the exterior to the interior surface. Compression slits 156 allow casing contact surface 134 to be compressed about bearing casing 122. The compression slits 154 and 156 allow the two ends of the lock ring to compress and expand relatively independently. Load ring 128 includes interior surface 157 and exterior surface 158.

Interior surface 157 is made up of cylindrical forward surface 160 and rearward surface 162 separated by shoulder 164. Forward surface 160 is threaded, and is threadably engageable over threaded end 144 of lock ring 126. Exterior surface 158 of load ring 126 includes wrench holes 165 suitable for receiving the ends of a tightening device. The tightening device is used to control the circumferential position of load ring 128 relative to lock ring 126.

With reference to FIGURE 9, shaft 124 is inserted into bearing casing 122 to the desired position. Lock ring 126 is inserted over shaft 124 and up to bearing casing 122 such that casing contact surface 134 surrounds the bearing casing. Load ring 128 is inserted over the shaft and lock ring, and threaded onto the latter.

As load ring 128 is tightened over lock ring 126, shoulder 164 is drawn toward and contacts wedged surface 146. Shoulder 164 creates a circumferential load line against wedged surface 146 that forces lock ring 126 to contract. Casing contact surface 134 and shaft contact surface 138 contract around the bearing casing and shaft, respectively. The load line is longitudinally positioned between casing contact surface 134 and shaft contact surface 138, i.e., radially above the intermediate surface, so that the two contact surfaces contract independently of one another. In this manner, maximum contraction of each portion of the lock ring 126 is obtained.

Using coupler 120, the shaft is radially centered within the bearing casing and the loads on the shaft and the bearing casing are dispersed across the surfaces of each where the coupler contacts them rather than at isolated point contacts. The length of casing contact surface 134 and shaft contact surface 138 affect the load carrying tasks of the bearing casing and shaft. For example, by extending the length of shaft contact surface 138, the load is distributed proportionally more to the shaft so that if a fault in operation occurs, the bearing will likely be the element damaged as opposed to the shaft.

The coupler 120 may be used on each end of a bearing casing. The use of a pair of couplers increases the load carrying ability of the coupled parts and further secures the relative positions of the parts. With reference to FIGURE 10, coupler 170 is provided for securing one or more machine elements, such as sheaves 172, and/or spacers 174, at a desired axial position along a shaft 176 that includes an axial keyway 178. Coupler 170 secures the axial and circumferential position of a machine element relative to the shaft.

Coupler 170 includes shaft casing 180, T-key 182, and shaft locks 184. Shaft easing 180 is a cylindrical hollow element slidably mountable along shaft 176. Shaft casing 180 includes inner key slit 186, outer key slit 188, interior surface 190, and exterior surface 192. Inner key slit 186 and outer key slit 188 form a through slit between the interior and exterior surfaces. Interior surface 190 includes a threaded surface 194 and a wedged surface 196 near each open end. Wedged surface 196 extends radially outwardly from threaded surface 194 towards the open end.

The circumferential position of shaft casing 180 relative to shaft 176 is fixed by T-key 182. T-key 182 includes lower portion 198 and upper portion 200. Lower portion 198 extends through inner key slit 186 into keyway 178 of shaft 176. Upper portion 200 rests in outer key slit 188 and extends radially above exterior surface 192. In this manner, T-key 182 couples the rotation of shaft 176 and shaft casing 180 while providing an exterior key to which the machine elements and spacers are keyed. Preferably, sheaves 172 and spacers 174 include keyways 202 and 204, respectively, extending radially outwardly from their interior surfaces.

The diameter of the bores of sheaves 172 and spacers 174 correspond to the diameter of exterior surface 192 of shaft casing 180. When T-key 182 is positioned within the inner and outer key slits, the circumferential positions of the sheaves and spacers mounted on shaft casing 180 are fixed by the mating of upper key portion 200 in the keyways 202 and 204.

Shaft locks 184 secure the position of shaft casing 180 axially and circumferentially along shaft 176. Shaft locks 184 are similar to shaft lock 90 of coupler 83. Each shaft lock includes interior surface 210 and exterior surface 212. Exterior surface 212 has threaded end 214, tapered load surface 216, and flanged head 218. The threads of threaded end 214 correspond to threaded surface 194 of shaft casing 180. The angle of tapered load surface 216 inversely correspond to the angle of wedged surface 196 of shaft casing 180. Flanged head 218 includes wrench holes 220. Each shaft lock 184 also includes through slit 222 and compression slits 224.

With reference to FIGURE 11, when a shaft lock is threaded into an open end of the shaft casing and tightened, tapered load surface 216 is axially displaced towards wedged surface 196. Wedged surface 196 acts against load surface 216 to force shaft lock 184 to contract. Shaft lock 184 thus contracts around and grips shaft 176. As shaft lock 184 is completely tightened within shaft casing 180, the circumferential and axial positions of shaft casing 180 relative to shaft 176 are made rigid. Shaft locks 184 are mounted over the shaft in opposite ends of the shaft casing.

Prior to the mounting and tightening of shaft locks 184 into shaft casing 180, sheaves 172 are mounted over the shaft casing. Spacers 174 are utilized to further control the axial position of a multiplicity of sheaves along shaft casing 180. By utilizing the sheaves, spacers and flanged heads 218, the sheaves 172 are axially positioned and held along shaft casing 180. The number and position of sheaves mounted on the shaft casing are thus easily modified using coupler 170. Once the sheaves and spacers are mounted, the shaft locks are mounted over the shaft and tightened into the shaft casing. In an alternative embodiment illustrated in FIGURE 12, shaft casing 230 includes threaded and wedged end 232 and a flanged head end 234. A shaft lock 184 is tightened into threaded and wedged end 232 to secure the axial and circumferential position of shaft casing 230 relative to shaft 176.

Flanged head end 234 includes flange 236, extending radially outwardly from shaft casing 230, and set screws 238. Set screws 238 extend through flange 236 parallel to shaft casing 230. Sheaves 172 and spacers 174 are secured between flanged head 218 and flange 236. Once shaft loek 184 is tightened into shaft casing 230, set screws 238 are tightened into flange 236 and against the closest sheave or spacer. In this manner, the positions of sheaves 172 and spacers 174 over shaft casing 230 are made rigid. The set screws compensate for the inability to exactly size the sheaves, spacers, and shaft casing lengths so that no spaces are left between the mounted components.

A variety of alternative methods are available for assuring that the axial positions of the sheaves and spacers are secured relative to shaft casings 180 and 230. For example, spacers 174, made of resilient material and slightly oversized, are compressed between the end flanges and the sheaves. In this manner, the sheaves are tightly held over the shaft casing.

If no rotational load is to be transferred between the shaft and the machine elements, then upper portion 200 of T-key 182 is not necessary. Lower portion 198 of the T-key, or another suitable securing device, would then secure the position of the shaft casing relative to the shaft lock to aid in tightening the shaft lock into the shaft casing. Whlle preferred embodiments of the invention have been illustrated and described, it will be appreciated that various changes can be made therein without departing from the spirit and scope of the invention. For example, in each embodiment, bushings or split bushings may be included to increase the range of shaft diameters with which the couplers are useful. - If the material used for the components is adequately resilient, no through slits or compression slits are necessary. Alternative means for securing the couplers relative to the machine elements are available. For example, tooth 106 on lock ring 91 may extend radially outwardly from the lock ring to fit into a shaft casing spline. Alternatively, a plurality of teeth may be used for each ring.

The component dimensions depend in part on the diameters of the shaft and the machine element to be coupled and in part on the resiliency or yield range of the coupler materials. Utilizing the above-described materials and designs, one size of coupler is suitable for use with a range of shaft and sheave hub diameters. With reference to coupler 10, alternative means for causing the axial displacement of the shaft lock and lock nut, and for securing the axial position of the two components relative to one another are available. For example, a variety of washers and nuts, adjustable screws, and/or springs would adequately provide these functions. As noted above, the couplers described herein are suitable for coupling a variety of machine elements to shafts. Additionally, coupler 120 is suitable for coupling two shafts together. The diameter of the two interior contact surfaces are configured so as to correspond to the diameters of the shafts to be coupled. Consequently, the invention can be practiced otherwise than as specifically described herein.

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A coupling device for coupling a shaft having a cylindrical surface and a machine element having a cylindrical bore, the device comprising: a resilient shaft lock, having a cylindrical interior surface, the diameter of which falls within the corresponding range of the shaft diameter, and an exterior surface having an extended end, and a first tapered load surface extending away and radially outwardly from said extended end; a resilient lock ring having a cylindrical exterior surface, the diameter of which falls within the corresponding range of the bore diameter, and an interior surface having first and second wedged surfaces, said wedged surfaces extending away and radially outwardly from a center line, said first wedged surface forming an angle that inversely corresponds to the angle of said first load surface; and a resilient lock nut having an interior surface corresponding in diameter to the diameter of the extended end, and having an exterior surface having a second tapered load surface forming an angle that inversely corresponds to the angle of said second wedged surface, said shaft lock, lock ring, and lock nut constructed and arranged so that the axial displacement of said lock nut in a first direction relative to said shaft loek causes said second load surface to be drawn toward said first load surface and causes said load surfaces to bear against said first and second wedged surfaces thereby causing said lock ring to radially expand, said lock nut to radially contract about said shaft lock, and said shaft lock to radially contract, and so that the axial displacement of said lock nut in a second direction relative to said shaft lock causes said second load surface to move away from said first load surface such that the load surfaces do not bear against said wedged surfaces thereby allowing said lock ring to contract and said lock nut and shaft lock to expand.

2. The coupling device as claimed in Claim 1, further including a means for securing the axial position of said lock nut relative to said shaft lock.

3. The coupling device as claimed in Claim 1, wherein said shaft lock extended end and said lock nut interior surface are correspondingly threaded, whereby the tightening of said lock nut over said shaft lock causes said lock nut to be displaced in said first direction, and whereby the loosening of said lock nut from about said shaft lock causes said lock nut to be displaced in said second direction.

4. The coupling device as claimed in Claim 1, wherein said shaft lock extended end is threaded, and wherein said coupling device further includes a tightening nut having a threaded interior surface corresponding to said extended end so that the tightening and loosening of said tightening nut over said extended end causes the axial displacement of said lock nut in the first and second directions, respectively.

5. The coupling device as claimed in Claim 1, wherein said shaft lock, lock ring, and lock nut each includes an axial through slot.

6. The coupling device as claimed in Claim 5, wherein said shaft lock, lock ring, and lock nut each includes a compression slit that extends partially through said component.

7. The coupling device as claimed in Claim 1, wherein said tapered load surfaces form an angle in the range of 20-30° with said shaft lock interior surface.

8. A method for coupling a shaft having a cylindrical surface and a machine part having a cylindrical bore, the method comprising the steps of: positioning a resilient shaft lock over the shaft at a position corresponding to the desired axial position of the machine element, said shaft lock having a cylindrical interior surface, the diameter of which falls within the corresponding range of the shaft diameter, and an exterior surf ce including an extended end and a first tapered load surface, said load surface extending radially outwardly from said threaded end; positioning a resilient lock ring over said shaft lock exterior surface, said lock ring including a cylindrical exterior surface, the diameter of which falls within the corresponding range of the bore diameter, and an interior surface having first and second wedged surfaces extending radially outwardly from a center line, the angle of said first wedged surface inversely corresponding to the angle of said first load surface; mounting the machine element over said lock ring; mounting a resilient lock nut over said shaft lock extended end, said lock nut including a cylindrical interior surface, the diameter of which falls within the corresponding range of the diameter of said extended end, and an exterior surface including a second tapered load surface, the angle of said second load surface inversely corresponding to the angle of said second wedged surf aee; axially displacing said lock nut such that said second load surface moves towards said first load surface thereby causing said first and second load surfaces to bear against said first and second wedged surfaces, respectively, and causing said lock ring to radially expand into and grip said machine element and said shaft lock and lock nut to radially contract such that the shaft lock grips the shaft.

9. The method for coupling as claimed in Claim 8, further comprising the step of securing the axial position of said lock nut relative to said shaft lock after said lock nut axial displacement.

10. The method for coupling as claimed in Claim 8, wherein said shaft loek extended end is threaded and said lock nut interior surface is threaded, said threaded surface corresponding to said extended end, and said step of axially displacing said lock nut includes the step of: tightening said lock nut onto said shaft lock such that said second load surface is drawn towards said first load surface thereby causing said first and second load surfaces to bear against said first and second wedged surfaces, respectively, and causing said lock ring to radially expand into and grip said machine element and said shaft lock and said lock nut to radially contract about the sha t such that the shaft lock grips the shaft.

11. The method of coupling as claimed in Claim 8, wherein said shaft lock extended end is threaded, and said step of axially displacing said lock nut includes the steps of: mounting a tightening nut over said shaft lock extended end, said tightening nut including a threaded interior surface corresponding to said extended end; and tightening said tightening nut onto said shaft lock such that said second load surface is axially displaced towards said first load surface.

12. A coupling device for coupling a shaft having a cylindrical surface and* a machine element having a cylindrical bore, the device comprising: a resilient shaft lock having a cylindrical interior surface, the diameter of which falls within the corresponding range of the diameter of the shaft, and an exterior surface, said exterior surface having a threaded end and a tapered load surface extending away and radially outwardly from said threaded end; and a resilient lock ring having a cylindrical exterior surface, the diameter of which falls within the corresponding range of the diameter of the bore, an interior surface including a wedged surface, a threaded surface, said wedged surface forming an angle that inversely corresponds to the angle of said load surface, and said threaded surface corresponding to said shaft lock threaded end, having circumferential locking means for limiting the rotation of said lock ring relative to said shaft lock, whereby the tightening of said shaft lock into said lock ring causes said load surface to be drawn towards and contact said wedged surface, thereby causing said lock ring to expand and causing said shaft lock to contract, and whereby the loosening of said shaft lock out of said lock ring causes said load surface to move away from said wedged surface thereby allowing said lock ring to contract and allowing said shaft loek to expand.

13. The coupling device as claimed in Claim 12, to be used in conjunction with a machine element that includes an axial keyway, wherein said circumferential locking means includes a tooth that is positionable within said axial keyway.

14. The coupling device as claimed in Claim 12, wherein said shaft lock and lock ring each includes an axial through slit.

15. The coupling device as claimed in Claim 14, wherein said shaft lock and lock ring each includes a compression slit that extends partially through said component.

16. The coupling device as claimed in Claim 12, wherein said tapered load surface forms an angle in the range of 20-30° with the shaft lock interior surface.

17. A method for coupling a shaft having a cylindrical surface and a machine element having a cylindrical bore, the method comprising the steps of: inserting a resilient lock ring into the bore, said lock ring including a means for preventing the rotation of said lock ring relative to the machine element, an exterior surf ce, the diameter of which falls within the corresponding range of the diameter of the bore, and an interior surface, said interior surface including a threaded surface and a wedged surface, said wedged surface extending radially outwardly and away from said threaded end; positioning a resilient shaft lock over the shaft and into said lock ring, said shaft lock having an exterior surface including a threaded end corresponding to said threaded surface of said lock ring, and a tapered load surface, the angle of which inversely corresponds to the angle of said wedged surface said shaft lock being positioned such that said load surface is adjacent said wedged surface and said threaded end is adjacent said threaded surface; and tightening said shaft lock into said lock ring such that said tapered load surface is drawn towards and against said wedged surface thereby causing said lock ring to expand into the machine element bore and causing said shaft lock to contract about the shaft.

18. A positioning device for positioning a machine element having a cylindrical bore along a shaft having a cylindrical surface, the device comprising: an open-ended shaft casing mountable on the shaft, said casing including a cylindrical interior surface and a cylindrical exterior surface, the diameter of which falls within the corresponding range of the bore diameter, said interior surface including, near one open end, a first surface, the diameter of which is greater than the diameter of the shaft, and a wedged surface, said wedged surface extending radially outwardly from said first surface to said open end; axial positioning means for securing the machine element between the ends of said shaft casing; and a resilient shaft lock, said shaft lock having a cylindrical interior surface, the diameter of which falls within the corresponding range of the shaft diameter, and an exterior surface having a tapered load surface forming an angle that inversely corresponds to the angle of said wedged surface, said shaft casing and shaft lock constructed and arranged so that the axial displacement of said shaft lock into said shaft casing causes said load surface to be drawn towards and against said wedged surface thereby causing said shaft lock to contract, and so that axial displacement of said shaft lock out of said shaft casing causes said tapered load surface to move away from said wedged surface thereby allowing said shaft lock to expand.

19. The positioning device as claimed in Claim 18, further including means for securing the axial position of said shaft lock relative to said shaft casing.

20. The positioning device as claimed in Claim 18, wherein said first surface is threaded, and said shaft lock includes a threaded end corresponding to said threaded surface, whereby the tightening of said shaft lock into said shaft casing, and the loosening of said shaft lock out of said shaft casing causes said axial displacement.

21. The positioning device as claimed in Claim 20, wherein said axial positioning means includes a first flanged head extending radially outwardly from said shaft lock exterior surface at the end of the shaf lock opposite said threaded end, and a second flanged head extending radially outwardly from said shaft casing at the open end opposite the open end near the threaded surface.

22. The positioning device as claimed in Claim 20, wherein each end of ^■ said shaft casing interior surface includes a threaded and a wedged surface and said positioning device further comprises a second shaft lock suitable for tightening into said shaft casing.

23. The positioning device as claimed in Claim 18, to be used with a shaft having a longitudinal keyway, wherein said shaft casing further includes an axial key slit that extends from said exterior surface to and through said interior surface, and wherein the positioning device further includes a T-key having lower and upper portions, said T-key fitting within said key slit such that said lower portion extends beyond said interior surface and said upper portion extends beyond said exterior surface, whereby the shaft and the machine element are keyed to said T-key lower and upper portions, respectively, to thereby secure the_^ circumferential position of the machine element relative to the shaft.

24. The positioning device as claimed in Claim 18, wherein said shaft lock includes an axial through slit.

25. The positioning device as claimed in Claim 24, wherein said shaft lock includes a compression slit extending partially through said shaft lock.

26. The positioning device as claimed in Claim 18, wherein said load surface forms an angle in the range of 20-30° with said shaft lock interior surface.

27. A method for positioning a machine element having a cylindrical bore along a shaft having a cylindrical surface, the method comprising the steps of: mounting an open-ended shaft casing over the shaft, said casing including a cylindrical interior surface and a cylindrical exterior surface, the diameter of which falls within the corresponding range of the bore diameter, said interior surface including, near one open end, a first surface, the diameter of which is greater than the diameter of the shaft, and a wedged surface that extends outwardly from said first surface to said open end; mounting a machine element over the shaft casing; securing the machine element over the shaft casing with axial positioning means; positioning a resilient shaft lock between the shaft and said first surface, of said shaft lock having a cylindrical interior surface, the diameter of which falls within the corresponding range of the shaft diameter, and an exterior surface, said exterior surface including a tapered load surface forming an angle that inversely corresponds to the angle of said wedged surface; and axially displacing said shaft lock into said shaft casing thereby causing said load surface to be drawn towards and against said wedged surface such that said shaft lock contracts about and lock against the shaft.

28. The method for positioning a machine element as elaimed in Claim 27, wherein said first surface is threaded, said shaft lock exterior surface includes a threaded end corresponding to said threaded surface, and wherein said step of axial displacement includes the steps of tightening and loosening said shaft lock within said shaft casing.

29. The method for positioning a machine element as claimed in Claim 28, further including the step of securing the circumferential position of the machine element relative to the shaft.

30. A device for coupling a machine element having an exterior cylindrical surface to a shaft having a cylindrical surface, said device comprising: a resilient lock ring having a cylindrical interior surface and a cylindrical exterior surface, said interior surface including a machine element contact surface, the diameter of which falls within the corresponding range of the diameter of the exterior surface of the machine element, a shaft contact surface, the diameter of which falls within the corresponding range of the shaft diameter, and an intermediate surface between said machine element contact surface and said shaft contact surface, said lock ring exterior surface having a first surface circumscribing a portion of said machine element contact surface, and a tapered load surface extending radially inwardly from said first surface and circumscribing said intermediate surface; and a load ring having a cylindrical exterior surface and a cylindrical interior surface, said interior surface having a first end, the diameter of which falls within the corresponding range of the diameter of said lock ring first surface, and a load shoulder spaced from said first end such that said load shoulder contacts said tapered load surface when said load ring is displaced over said lock ring, a said lock ring and load ring constructed and arranged so that the axial displacement of said load ring relative to said lock ring causes said load shoulder to contact said tapered load surface thereby causing said lock ring to contract.

31. The device as claimed in Claim 30, further including means for securing the axial displacement of said load ring.

32. The device as claimed in Claim 30, wherein said lock ring first surface is threaded, said load ring first end is threaded, and whereby the tightening and loosening of said load ring over said lock ring causes the axial displacement of said load ring.

33. The device as claimed in Claim 30, wherein said lock ring includes an axial through-slit, a plurality of machine element slits extending radially from said machine element contacting surface to and through said threaded surface, and a plurality of shaft slits extending radially from said shaft contact surface and terminating before said exterior surface.

34. A method for coupling a machine element having an exterior cylindrical surface to a shaft having a cylindrical surface, said method comprising the steps of: mounting a resilient lock ring over the shaft and the machine element, said lock ring having a cylindrical interior surface and a cylindrical exterior surface, said interior surface including a machine element contact surface, the diameter of which falls within the corresponding range of the diameter of the exterior surface of the machine element, a shaft contact surface, the diameter of which falls within the corresponding range of the diameter of the shaft, and an intermediate surface between said machine element contact surface and said shaft contact surface, said lock ring exterior surface having a first surface circumscribing said machine element contact surface, and a tapered load surface extending radially inwardly from said first surface and circumscribing said intermediate surface; mounting a load ring over said lock ring, said load ring having a cylindrical exterior surface and a cylindrical interior surface, said interior surface having a first end, the diameter of which falls within the corresponding range of the diameter of said lock ring first surface, and a load shoulder spaced from said first end such that said load shoulder contacts said tapered load surface when said load ring is displaced over said lock ring; and, axially displacing said load ring over said lock ring such that said load shoulder contacts the tapered load surface thereby causing said lock ring to contract about and lock against the machine element and the shaft.

35. The method for coupling as claimed in Claim 34, wherein said first surface and said first end are correspondingly threaded, and said step of axially displacing said load ring includes the step of tightening said load ring over said lock ring.