Abstract:
A mounting device for coaxially anchoring a machine element upon a rotary shaft. The device fits between the interior bore of the machine element and the cylindrical surface of the shaft and is effective to position the element at any desired position longitudinally of the shaft and at any angular position circumferentially of the shaft. The device has inner and out sleeves, the mating surfaces of which are similarly tapered so that relative axial displacement of the sleeves effects expansion and contraction of the interior bore and external surface of the combined elements. Rotation of a threaded nut at one end of the device effects the relative axial displacement of the inner and outer sleeves to afford expansion and contraction of the outer sleeve.

Description:
This application claims benefit of provisional application No. 60/028,249, filed Oct. 9, 1996. This application is a 371 of PCT/US97/18225, filed Oct. 8, 1997. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to a mounting device for mounting a machine element upon a shaft in such a manner that the rotation of the shaft transmits its entire torque to the machine element without slippage due to the mounting. In particular, the device of the present invention provides an improved mounting device for mounting machine elements permitting infinitely-variable adjustment of the machine element on the shaft, both axially of the shaft and circumferentially thereof, and maintaining the machine element at a fixed, axial position after mounting on the shaft. 
     BACKGROUND OF THE INVENTION 
     The use of devices for mounting machine elements, such as pulleys and gears, upon a shaft is well-known. One difficulty is that the known devices for mounting a machine element upon a cylindrical shaft are cumbersome to use. For example, some devices require assembly of multiple pieces and adjustment of several screws, and other devices require modification of the shaft on which the machine element is mounted. 
     Another difficulty encountered relates to machine elements having undersized bores and oversized shafts. Frequently, due to wear, the internal bore of a machine element may be undersized and, similarly, the diameter of a shaft may be oversized. In these situations, the mounting device must be able to fit within the bore, or over the shaft. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The foregoing summary, as well as the following detailed description of the preferred embodiments of the present invention, will be better understood when read in conjunction with the appended drawings, in which: 
     FIG. 1 is a fragmentary exploded perspective view of a mounting device, in accordance with the present invention, in position for coupling a machine element to a shaft; 
     FIG. 2 is an end view of the assembled mounting device as seen from the right-hand end of FIG. 1; 
     FIG. 3 is a transverse sectional view taken on the section line  3 — 3  of FIG. 2; 
     FIG. 4 is a fragmentary exploded perspective view of a second embodiment of a mounting device in accordance with the present invention; 
     FIG. 5 is an end view of the assembled mounting device as seen from the left-hand end of FIG. 4; 
     FIG. 6 is a transverse sectional view taken on the section line  6 — 6  of FIG.  5 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to the drawings and to FIGS. 1-3 specifically, a mounting device  10  designed to mount the hub of a machine element  11  upon a cylindrical shaft  12  is illustrated. In the present instance, the machine element  11  has a smooth tapered bore  13  whose axis coincides with the axis of the cylindrical surface of the shaft  12 . The mounting device is designed to be positioned between the bore  13  and the shaft  12  and to be expanded therein to securely anchor the machine element  11  on the shaft at any desired position axially of the shaft and any angular position circumferentially of the shaft. In the present instance, the bore of the machine element is tapered, however, the bore could alternatively be cylindrical. 
     The mounting device  10  incorporates an inner sleeve  21 , an outer sleeve  22 , and a locking nut  23 . The inner sleeve  21  is tubular in form having an internal cylindrical bore whose diameter corresponds to the diameter of the shaft  12 , the bore being of sufficiently greater diameter than the shaft to permit free sliding movement of the inner sleeve  21  on the shaft both axially and circumferentially, with the proximal end of inner sleeve  21  having a threaded section  31 . The distal end of the inner sleeve  21  has an outwardly-tapered external surface  26 . A plurality of terminated longitudinally-extending slots  27  are spaced about the periphery of the inner sleeve. As shown in FIG. 1, all of the slots terminate short of the proximal end  29  so that the proximal end of the inner sleeve is a continuous solid ring  60 . Referring to FIG. 3, the proximal end of the inner sleeve  21  has an annular recessed portion  65  extending about the entire inner circumference of the sleeve. The recessed portion is larger in diameter than the cylindrical shaft  12 . The annular recessed portion  65  is at least coextensive in length with the continuous band  60  of the inner sleeve  21 , and preferably is coextensive with the threaded portion  31 . The annular recessed portion  65  is sufficiently deep so that the continuous band  60  is thin enough to provide sufficient flexibility for the inner sleeve  21 . 
     The inner sleeve  21  is adapted to fit within the outer sleeve  22  which, in the present instance, is a segmented sleeve having three axial slots  37  extending through the outer sleeve dividing the outer sleeve into three separate segments. Alternatively, the axial slots may be terminated slots so that the outer sleeve  22  is of one-piece construction. The axial slots  37  permit radial deflection of the outer sleeve  22  as the mounting device is tightened and released. The outer surface of the outer sleeve  22  is tapered having a taper that corresponds to the tapered bore  13  of the machine element  11 , the diameter of the outer sleeve being of sufficiently smaller diameter than the bore to permit free sliding movement between the machine element and the outer sleeve when the mounting device is not tightened. Alternatively, if the machine element has a cylindrical bore, the outer surface of the outer sleeve is cylindrical to correspond to the machine element bore. 
     As shown in FIG. 3, the inner surface of the outer sleeve  22  tapers toward the forward end at the same angle of taper as the inner sleeve  21 . In this way, when outer sleeve  22  is rearwardly-displaced relative to the inner sleeve  21  (i.e., from right to left in FIG.  3 ), the tapered surfaces of the inner and outer surfaces cooperate to expand the external tapered surface of the outer sleeve and contract the internal cylindrical surface of the inner sleeve, the contraction and expansion of the surfaces being substantially parallel to the common central axis of the assembly. 
     As shown, the rearward end of the outer sleeve  22  has a circumferential interlock that engages an annular groove in the nut  23 . The outer sleeve  22  is displaced relative to the inner sleeve  21  by means of the nut  23 . To this end, as illustrated in FIGS. 1 and 3, the nut has internal threads  38  which threadedly engage the threads  31  of the inner sleeve  21 . Rotating the nut  23  axially displaces the nut relative to the inner sleeve. Because the outer sleeve is connected to the nut, the outer sleeve is displaced relative to the inner sleeve as the nut is displaced. 
     The continuous band  60  of the inner sleeve provides greater thread strength and improved threaded engagement with the nut  23 , relative to a sleeve that is split along the entire axial length. In addition, by providing with the annular groove  65  the inner sleeve  21  retains sufficient flexibility so that the distal end  30  adjacent the tapered surface  26  can flex over the shaft  12  if the shaft is slightly oversized. Further, the annular recessed portion  65  provides a clearance recess so that the continuous band  60  can slide over the shaft  12  if the shaft is oversized. 
     Referring now to FIGS. 4-6, a second embodiment for a mounting device is illustrated. The second embodiment  10 ′ is shown in combination with a cylindrical shaft  12 ′ and a machine element  11 ′ having a cylindrical bore  13 ′. The second embodiment  10 ′ has an inner sleeve  20 ′, an outer sleeve  50 ′, and a nut  45 ′. 
     The inner sleeve  20 ′ has a cylindrical bore corresponding to the diameter of the shaft  12 ′. An internal groove  26 ′ and an inwardly-projecting flange  24 ′ adjacent the proximal end of the inner sleeve  20 ′ form a circumferential interlock that engage the nut  45 ′. The external diameter of the inner sleeve has a tapered surface that mates with the outer sleeve  50 ′. In the present instance, the inner sleeve is of one-piece construction having a series of terminated slots  22   a ′ forming a web  32 ′. The web  32 ′ is configured so that the interlock of the inner sleeve can resiliently expand over an outwardly-extending flange  48 ′ of the nut  45 ′. 
     The outer sleeve  50 ′ has an internally-threaded section  52 ′ adjacent the proximal end  56 ′ of the outer sleeve. The distal end of the outer sleeve has a tapered surface for mating engagement with the external tapered surface of the inner sleeve. 
     A series of terminated axially-extending slots  54 ′ are circumferentially spaced about the circumference of the outer sleeve  50 ′. All of the slots  54 ′ terminate short of the proximal end of the outer sleeve  50 ′ so that the proximal end of the outer sleeve has a continuous band  70 ′. In addition, the outer sleeve has an annular recessed portion  75 ′ on the outer surface adjacent the proximal end. The external recessed portion  75 ′ is at least coextensive with the continuous band  70 ′ and is preferably coextensive with the internal threads  52 ′. 
     The outer sleeve  50 ′ is displaced relative to the inner sleeve  20 ′ by means of the nut  40 ′. To this end, as illustrated in FIGS. 4 and 6, the nut  40 ′ has external threads  42 ′ which threadedly engage the threads  52 ′ of the outer sleeve  50 ′. Rotating the nut  40 ′ displaces the nut axially relative to the outer sleeve. Because the inner sleeve  20  is connected to the nut, the inner sleeve is displaced relative to the outer sleeve as the nut is displaced. In this way, rotating the nut in a forward direction displaces the outer sleeve relative to the inner sleeve so that the tapered surfaces of the inner and outer sleeves cooperate to expand the external surface of the outer sleeve to engage the bore  13 ′ and contract the internal surface of the inner sleeve to engage the shaft  12 ′. 
     The continuous band  70 ′ of the outer sleeve provides greater thread strength and improved threaded engagement with the nut  40 ′, relative to a sleeve that is split along the entire axial length. In addition, by providing the annular recessed portion  75 ′, the outer sleeve  50 ′ retains sufficient flexibility so that the distal end adjacent the internally-threaded surface can flex inwardly into the bore  13 ′ if the bore is slightly undersized. In addition, the annular recessed portion  75 ′ provides a clearance recess so the continuous band  70 ′ can fit within the bore  13  if the bore is undersized.