Abstract:
Mechanism for providing and controlling long stroke turret slide movement in an automatically operable screw machine. Means are provided to obtain a longer stroke of the turret slide than is normally possible in an automatically operable screw machine. Fluid operable means control the movement of the turret slide member or turret support member with respect to a mechanically operable carrier member upon which the turret slide member rests.

Description:
BACKGROUND OF THE INVENTION 
     In a conventional automatically operable screw machine a turret is rotatably supported by a turret slide member or turret support member which is adjustably movable upon a gear rack or the like. The gear rack has a toothed surface and is movable by means of a pivotal lever which has a toothed portion at one end thereof which is in mesh with the toothed surface of the rack. The turret is moved toward and away from a spindle or chuck by pivotal movement of the lever, which moves the rack, which supports the support member, which supports the turret. It has been learned that there are numerous operations of an automatically operable screw machine in which a long stroke of the turret is desired. Frequently, the desired stroke of the turret is in excess of the capability of the machine. 
     It is an object of this invention to provide means by which a conventional automatically operable screw machine can be modified to provide for a much longer turret stroke than is otherwise possible. 
     It is another object of this invention to provide means by which a conventional automatically operable screw machine can be modified to produce a longer turret stroke by combining therewith a reciprocally operable motor. 
     It is another object of this invention to provide means by which a longer turret stroke can be obtained by combining therewith a fluid motor and by also modifying a mechanical portion of the machine. 
     Another object of this invention is to provide means by which the pressure which is applied by a turret tool to a work piece is sensed for indication of the pressure and/or for control of the machine. 
     It is another object of this invention to provide such means which is relatively low in cost and which can be readily and easily applied to a conventional screw machine. 
     Other objects and advantages of this invention reside in the construction of parts, the combination thereof, the method of manufacture, and the mode of operation, as will become more apparent from the following description. 
     SUMMARY OF THE INVENTION 
     The long stroke turret slide control mechanism of this invention comprises means for increased movement of a turret support member with respect to a toothed rack upon which the turret support member moves. Fluid operable actuator means are attached to the geared rack, which carries the turret support member, and to the turret support member for producing relative movement therebetween. Means are also provided for altering the location of the toothed rack with respect to a base of the machine in order to increase the normal maximum position of the turret with respect to the spindle or chuck. Means are also provided for sensing the pressure for indication and/or for control of the machine. 
    
    
     BRIEF DESCRIPTION OF THE VIEWS OF THE DRAWINGS 
     FIG. 1 is a fragmentary sectional view of a portion of a rack and turret support member of a conventional automatically operable screw machine. 
     FIG. 2 is a diagrammatic type of sectional view, with parts broken away, drawn on a slightly smaller scale than FIG. 1, illustrating a modification in a conventional screw machine to provide for greater movement of the turret with respect to a spindle. 
     FIG. 3 is a sectional view of the apparatus of FIG. 2, showing the position of the elements of the apparatus during movement of the turret toward the spindle. 
     FIG. 4 is a sectional view, similar to FIGS. 2 and 3, showing the position of the elements of the apparatus when the turret is positioned at a minimum distance from the spindle. 
     FIG. 5 is a fragmentary diagrammatic type of sectional view illustrating a modification in the apparatus of FIGS. 2-4. 
     FIG. 6 is a fragmentary diagrammatic type of sectional view, similar to FIG. 5, but showing the elements of the apparatus in another position of operation. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A conventional automatically operable screw machine has a turret attached to a support member and the support member is adjustably carried by a toothed rack. FIG. 1 shows a portion of a conventional screw machine in which a turret support member 10 is adjustably carried upon a rack or carrier 12 which has teeth, not shown in FIG. 1, for mechanical movement thereof. The rack 12 is movable upon a way 14. A bolt 16 or the like extends through a portion of the support member 10 and also extends through an opening 18 in the rack 12. An adjustment screw 20 is carried by the rack 12 and is engageable with the support member 10 to adjust the position of the support member 10 with respect to the rack 12. The support member 10 can be adjusted with respect to the rack 12 within the limits of the opening 18 through which the bolt 16 extends. Thus, by means of the adjustment screw 20 the position of a turret, not shown, carried by the support member 10, is adjusted with respect to the rack 12 and with respect to a spindle at any position of the rack 12. The bolt 16 secures the adjusted position of the support member 10 with respect to the rack 12. Thus, the position of the support member 10 with respect to the rack 12 is maintained during reciprocal movement of the rack 12 and the support member 10. It has been found in operation of such a conventional automatically operable screw machine that the maximum or minimum spacing of a turret with respect to a spindle is not sufficient to accomplish a long stroke cutting operation, which is desired in numerous types of work. 
     FIGS. 2, 3, and 4 
     FIGS. 2, 3, and 4 illustrate the manner in which a conventional automatically operable screw machine is modified in accordance with this invention to obtain a longer turret stroke than is otherwise possible. The adjustment screw 20 and the bolt 16 are removed from the support member 10 and the rack or carrier 12. An actuator rod 24 is attached to the rack or carrier 12. A bracket 26 is attached to the support member 10. The bracket 26 and the support member 10 attached thereto are shown as being urged in a direction toward the right as viewed in FIGS. 2, 3, and 4 by any suitable resilient member 28. The bracket 26 has attached thereto a fluid housing 30 of a reciprocally operable fluid motor 32. Within the fluid housing 30 is a piston 36 which is axially movable with respect thereto. The piston 36 has attached thereto the actuator rod 24. 
     Rotatably carried by the support member 10 is a turret 40 which, with movement of the support member 10, is movable toward and away from a spindle or chuck 44, which is adapted to retain a work piece. Thus, the support member 10 and the rack 12 serve as turret support means for movement of the turret 40. 
     The rack 12 has a toothed portion 12a which is in meshed engagement with a toothed portion 48a of a lever 48. The lever 48 is pivotal about a trunnion 50 which is supported by a block 52. The trunnion 50 is retained in position by a cam 54, which is rotatable about an axis 56. Pivotally attached to an end of the lever 48 opposite the toothed portion 48a, is a link 58, to which is pivotally attached a pivotal cam follower lever 62, which engages a cam 66. The cam 66 is supported by a shaft 68 and is rotatable therewith. 
     Also rotatable with the shaft 68 is a cam 72 which is engaged by a cam follower 74. An arm 76 is pivotally attached to the cam follower 74 and is also pivotally attached to support structure 78. The cam follower 74 is joined to a rod 80 which is attached to a piston 82 within a fluid housing 84 of a fluid pump 86. A fluid conduit 88 joins the left-hand portion of the fluid housing 84 to the left-hand portion of the fluid housing 30. 
     The cam 72, the cam follower 74, the arm 76, the rod 80, the piston 82, the fluid housing 84, and the fluid conduit 88, in addition to the rod 24, and the fluid motor 32, are not found in conventional screw machine and are added to a conventional screw machine in accordance with this invention. 
     Operation 
     FIG. 2 shows the rack 12 positioned at its maximum distance from the spindle or chuck 44, and the support member 10 is positioned at its maximum distance from the spindle or chuck 44. Thus, the turret 40 is positioned at a maximum distance from the spindle 44. The shaft 68 rotates in a clockwise direction and moves therewith in a clockwise direction the cam 66, as illustrated. As such rotative movement of the cam 66 occurs, the cam follower lever 62 is pivotally moved and, through the link 58, pivotally moves the lever 48 in a counter clockwise direction. The toothed portion 48a of the lever 48 in meshed relationship with the toothed portion 12a of the rack 12 causes linear movement of the rack 12 in a direction toward the spindle or chuck 44. As the rack 12 is moved toward the spindle 44, the rack 12 carries therewith the support member 10. Thus, the turret 40 and any tool carried thereby are moved toward the spindle 44. Movement of the rack 12 toward the spindle 44 moves therewith the actuator rod 24, and movement of the support member 10 towards the spindle 44 carries therewith the bracket 26 and the fluid motor 32. 
     As stated above and as illustrated in FIGS. 2, 3, and 4, the cam 72 is also joined to the shaft 68 for rotation therewith. Therefore, with rotation of the shaft 68 in a clockwise direction, the cam 72 rotatively moves in a clockwise direction. As the cam 72 rotatively moves in a clockwise direction, the cam follower 74 is moved toward the fluid housing 84 and the piston 82 within the fluid housing 84 is moved toward the left portion of the fluid housing 84. When this occurs, fluid within the fluid housing 84 is forced by the piston 82 in a direction from the fluid housing 84 and into the fluid conduit 88. Fluid flowing through the fluid conduit 88 from the fluid housing 84 moves into the left-hand portion of the fluid housing 30. The position of the piston 36 within the fluid housing 30 is determined by the position of the rack 12, to which the actuator rod 24 is attached. Thus, when fluid is forced into the fluid housing 30 through the fluid conduit 88, the fluid housing 30 is forced to move toward the spindle 44 and to move in this direction with respect to the piston 36. Thus, when fluid is forced into the fluid housing 30 the support member 10 moves toward the spindle 44. Such movement of the support member 10 is with respect to the rack 12. 
     Therefore, as the shaft 68 rotates from the position thereof shown in FIG. 2 to an intermediate position shown in FIG. 3, the rack 12 is moved by the lever 48 toward the spindle 44 to an intermediate position, as shown in FIG. 3, and, at the same time, the support member 10 is moved forwardly toward the spindle 44 to an intermediate position with respect to the rack 12. Furthermore, when the lever 48 has moved the rack 12 toward the spindle 44 to the maximum travel, as determined by the toothed portions 48a and 12a, as illustrated in FIG. 4, the fluid motor 32 has moved the support member 10 with respect to the rack 12 the maximum travel as determined by the position of the bracket 26 with respect to the rack 12, as the bracket 26 comes into engagement with the rack 12, as shown in FIG. 4. Thus, the turret 40 is moved from a maximum position with respect to the spindle 44, as shown in FIG. 2, to its minimum distance with respect to the spindle 44, as shown in FIG. 4. Such travel of the turret 40 is greater than maximum travel obtainable in a conventional apparatus illustrated in FIG. 1. This is due to the fact that the maximum fixed adjustment of the support member 10 with respect to the rack 12 has been changed to an operational travel of the support member 10 with respect to the rack 12. 
     It is to be understood that the rack 12 and the support member 10 can be operated in accordance with this invention in a manner such that complete travel of the rack 12 is completed before or after complete travel of the support member 10 with respect to the rack 12 toward the spindle 44. 
     The cam 54 serves as a withdrawal cam for rapid withdrawal of the turret 40 with rotative movement of the cam 54, which permits the spring 28 to move the trunnion 50 to the right and thus to move the pivotal axis of the lever 48 and the rack 12 to the right. 
     FIGS. 5 and 6 
     FIGS. 5 and 6 illustrate further modification of a conventional screw machine for the purpose of obtaining greater travel or stroke of the turret 40. As shown in FIG. 5, the turret 40 is moved to a maximum distance from the spindle 44. This distance is greater than the maximum distance of the turret 40 from the spindle 44 shown in FIG. 2. In the apparatus as shown in FIG. 5 the pivotal axis of the lever 48 is moved toward the right by movement of the trunnion 50 to the right. In order to obtain this movement of the trunnion 50 to the right, the cam 54 is reduced in size or moved to the right. Thus, the toothed portion 48a of the lever 48 is moved farther to the right and the rack 12 is moved farther to the right. Movement of the rack 12 farther to the right permits movement of the support member 10 farther to the right. Thus, the turret 40 is moved to the right from the position thereof, shown in FIG. 2, to the position thereof shown in FIG. 5. Thus, the turret 40 has a maximum spaced position from the spindle 44 greater than the maximum spacing of the turret 40 from the spindle 44 possible in the apparatus as shown in FIGS. 2, 3, and 4. FIG. 5 shows a modification by insertion of a spacer block 90 between the bracket 26 and the support member 10, in order to provide greater spacing between the bracket 26 and the rack 12. This can also, of course, be accomplished by reshaping the bracket 26 to permit greater travel of the support member 10 with respect to the rack 12. Thus, in operation of the apparatus of FIGS. 5 and 6 the turret 40 begins its travel toward the spindle 44 from a position farther from the spindle 44 than is possible with the apparatus shown in FIG. 2. 
     In operation, as the lever 48 is pivotally moved, through rotative movement of the cam 66, the rack 12 is moved toward the spindle 44. As the rack 12 travels toward the spindle 44, the cam 72, rotatively moving with the cam 66 and operating upon the piston 82, forces fluid into the fluid housing 30. The fluid housing 30, attached to the support member 10, forces the support member 10 to move toward the spindle 44 with respect to the rack 12. Thus, the support member 10 is moved forwardly with respect to the rack 12 until the bracket 26 engages the rack 12, as shown in FIG. 6. This travel of the support member 10 with respect to the rack 12 is greater than the travel possible with the apparatus as shown in FIGS. 2, 3, and 4. This is due to the fact that the turret 40 is moved from a maximum position spaced farther from the spindle 44 to a minimum position equal to that shown in FIG. 4. Thus, the travel or stroke of the turret 40 is greater than the travel or stroke of the turret 40 in the apparatus as shown in FIGS. 2, 3, and 4. 
     Also shown in FIG. 5 is a connector fluid conduit 94 which joins the fluid conduit 88 to a unit 98. The unit 98 senses the fluid pressure in the fluid conduit 88. The fluid within the fluid motor 32 forces a tool carried by the turret 40 into engagement with a work piece which is retained by the spindle or chuck 44. Thus, the pressure of the fluid within the fluid motor 32 and within the fluid conduit 88 is directly related to the force required to effect operation upon a work piece by a tool carried by the turret 40. Thus, the unit 98 senses the force required to effect operation upon a work piece by a tool carried by the turret 40. When a tool carried by the turret 40 wears or breaks, the pressure applied to a work piece by the tool increases. Such increase may be sudden or gradual. Thus, the pressure increase sensed by the unit 98 may be sudden or gradual. The unit 98 may be an indicator which indicates pressure, so that an operator when observing the pressure increase above a given value stops the screw machine from further operation. The unit 98 may be a pressure sensitive switch element which is joined to means for controlling or for stopping the screw machine when fluid pressure of a predetermined magnitude exists within the fluid conduit 88. Thus, the unit 98 is employed to protect the screw machine from damage which may result from worn or broken turret tools. The protection may be automatic or visual and manual. 
     Although the preferred embodiment of the device has been described, it will be understood that within the purview of this invention various changes may be made in the form, details, proportion and arrangement of parts, the combination thereof, and mode of operation, which generally stated consist in a device capable of carrying out the objects set forth, as disclosed and defined in the appended claims.