Patent Number: 054004993
Section: description

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 4A, the internal bushing removal tool in accordance with the preferred embodiment is shown during insertion into the piston coupling 24c. The tool comprises a ram arm 104 having a bore 104e (see FIG. 5A) for receiving the shaft of a swivel pin 105 (see FIG. 5B). A swivel arm 103 (see FIG. 5C) has a swivel block 103f with a bore 103e for receiving swivel pin 105. Block 103f resides inside a cavity 104f in ram arm 104. Swivel arm 103 is held in place on swivel pin 105 (with two machined wrench flats) by a hex nut 106 with a lock washer 107 therebetween (see FIG. 6). The swivel arm and ram arm have opposing surfaces separated by gap 111a and 111b that allow a small angle of rotation of swivel arm 103 about the axis of swivel pin 105 and relative to ram arm 104. The arms 103 and 104 have opposing seats 103b, 104b and 103c, 104c for receiving respective ends of concentrically arranged inner (109) and outer (110) springs (see FIG. 4A). A guide pin 108 mounted on ram arm 104 projects inside inner spring 109 along its axis to guide the windings during compression of the spring, thereby restraining non-axial flexing of the spring. The inner and outer springs are compression springs which urge the ram and swivel arms apart, until full open stop is achieved by contact of adjacent surfaces of 103f and 104f. The ram arm 104 has an arcuate shoulder with a radial arcuate contact surface 104a (see FIG. 7). Similarly, the swivel arm 103 has an arcuate shoulder with a radial arcuate contact surface 103a. Inclined rigid members 103g and 104g connect the contact surfaces to the bored members that mount on swivel pin 105. At the position shown in FIG. 4A, the inclined portions 103g and 104g bear against the near inner peripheral edge of the internal bushing 63 to be removed. In a conventional CRD, the bore of each internal bushing 63 has a radius less than the radius of the bore of piston coupling 24c. As the removal tool is forced leftward from that position, the inner peripheral edge of the bushing will exert radially inwardly directed forces which overcome the spring forces urging ram and swivel arms 103, 104 apart. As a result, the contact surfaces 103a and 104a travel through the bore and past the far inner peripheral edge of the bushing. When the contact surfaces clear the far inner peripheral edge of bushing 63, the arms are urged apart by springs 109 and 110. The outer peripheral edge of each contact surface is pushed radially outward to a locus beyond the radius of the bore of bushing 63 (as shown in FIG. 4C), thereby latching the removal tool to the internal bushing. In the latched position, contact surface 103a abuts the internal bushing along a first arc and contact surface 104a abuts the internal bushing along a second arc diametrally opposed to the first arc. In these positions, the arcuate contact surfaces will bear against diametrally opposed portions of the end face of the internal bushing. Thus, swivel arm 103, ram arm 104, swivel pin 105, inner spring 109 and outer spring 110 form a springloaded collet having a pair of arc-shaped contact surfaces which can be latched behind the far inner peripheral edge of the internal bushing to be removed. These contact surfaces are then forced against the bushing end face to push bushing 63 out of the corresponding recess in piston coupling 24c. The respective ends of arms 103 and 104 are provided with cylindrical concavities 103d and 104d, respectively, to reduce the mass of the arms. These ends serve as handles by which the arms can be manually pressed together during the insertion step of FIG. 4A. The removal tool in accordance with the invention further comprises a ram 102 which screws into an end portion of ram arm 104. Ram 102 is preferably a solid cylinder having a flat end. During removal of the internal bushings, ram 102 and piston coupling 24c are held in horizontal or vertical positions by means of a stand 120 (see FIG. 8). Stand 120 is a cylindrical tube with a chamfered inlet 124 and an annular shoulder 122 which separates bores 128 and 130 of different diameter. Bore 128 receives the end of the piston coupling 24c, with the annular end face 121 of piston coupling 24c sitting on and supported by shoulder 122. A hammer or mallet is impacted against the flat end of ram 102 to drive the tool along the longitudinal axis and out of the piston coupling 24c. The force of the impact is transferred via contact surfaces 103a and 104a to the opposing radial end face of the internal bushing, thereby pushing the bushing axially out of the annular recess in which it is seated (see FIG. 4C), without damage to the piston coupling. A window 126 allows the operator to view the progressive downward displacement of bushing 63. The diameter of bore 130 is such that the removed bushing 63 passes through. The preferred embodiment of the internal bushing removal tool has been disclosed for the purpose of illustration. Variations and modifications of the disclosed structure which do not depart from the concept of this invention will be readily apparent to mechanical engineers skilled in the art of tooling. All such variations and modifications are intended to be encompassed by the claims set forth hereinafter.