US2756551A

US2756551A - Grinding machine steadyrest

Info

Publication number: US2756551A
Application number: US452656A
Authority: US
Inventors: Charles C Alvord
Original assignee: Norton Co
Current assignee: Saint Gobain Abrasives Inc
Priority date: 1954-08-27
Filing date: 1954-08-27
Publication date: 1956-07-31
Anticipated expiration: 1973-07-31

Description

July 31, 1956 c. c. ALVORD 2,756,551

GRINDING MACHINE STEADYRBST Filed Aug. 27, 1954 INVENTOR. /i CHARLES C. ALvmep M Elmo.

ATTo RNEY nited States Patent GRINDING MACHINE STEADYREST Charles C. Alvord, Worcester, Mass., assignor to Norton Company, Worcester, Mass., a corporation of Massachusetts Application August 27, 1954, Serial No. 452,656

Claims. (Cl. 51238) engage the work piece in a horizontal plane passing through the work axis, and a pivotally mounted shoe which is arranged to engage the work piece from below at a position adjacent to the line of contact between the grinding wheel and the work piece being ground. Another object is to provide a two-bearing shoe steadyrest in which a single piston and cylinder is provided for moving the steadyrest shoes to and from an operative position supporting engagement with the work piece during a grinding operation. Another object is to provide a two-bearing shoe steadyrest in which a single nut and screw mechanism is provided for moving the steadyrest shoes to and from an operative position and for maintaining the shoes in operative supporting engagement with the work piece during a grinding operation. Another object of the invention is to provide a hydraulically operated nut and screw mechanism including a pivotally mounted cross arm which is arranged so as to first move the lower steadyrest shoe into operative engagement with the work piece and to maintain it in operative contact with the work at a desired pressure after which the horizontal shoe is moved into operative engagement and maintained in operative engagement at a lower pressure until the work piece has been ground to a predetermined size.

A further object of the invention is to provide a hydraulically actuated cross arm mechanism operatively connected to move both of the work steadying shoes in 2,756,551 Patented July 31, 1956 mounted upon a grinding machine table or base 11. The improved steadyrest comprises a steadyrest base 10 which is adjustably fastened to the base 11 by a clamping screw 12 which passes through an elongated slot in the steadyrest base 10 and is screw threaded into the base 11.

In order to facilitate a lateral adjustment of the steadyrest base 10 relative to the base 11, a bracket 13 is fastened to the machine base 11 and is provided with a pair of spaced upwardly projecting

integral bosses

14 and 15. The

bosses

14 and 15 project upwardly on opposite sides of the steadyrest base 10, as shown in Fig. 2. The

bosses

14 and 15 are provided with opposed adjusting screws 16 and 17 respectively Which are screw threaded through the

bosses

14 and 15 and bear against opposite side faces of the steadyrest base 10. A clamping screw 18 passes through an elongated slot 19 formed in the steadyrest base 10 and is screw threaded into the base 11 to facilitate clamping the left hand end of the steadyrest base (Fig. 1). It will be readily apparent that by loosening the clamping

screws

12 and 18 and manipulating the opposed screws 16 and 17 that the steadyrest base 10 may be adjusted longitudinally relative to the machine base 11 so as to position the steadyrest in a predetermined relationship with a rotatable grinding wheel 20.

The steadyrest is provided with a pair of work steadying shoes including a horizontally adjustable shoe 25 and a pivotally adjustable shoe 26. A shoe holder 27 is slidably keyed within a cylindrical aperture 28 formed in the steadyrest base 10. A manually operable rotatable adjusting screw 29 is screw threaded into the left hand end of the shoe holder 27. The rotatable screw 29 is journalled in a slidably mounted sleeve 30 which is keyed within the aperture 28. The screw 29 is provided with an integral flange 31 which serves as a thrust flange against the right hand end of the sleeve 30. A collar 32 is pinned to the screw 29 at the other end of the sleeve 30 to take up the thrust at the other end of the sleeve 30. A manually operable adjusting knob 33 is mounted on the left hand end of the feed screw shaft 29.

The lower or pivotally mounted steadyrest shoe 26 is mounted on a pivotally mounted arm 35 which is supported by a pivot stud 36 carried by the steadyrest base 10. The arm 35 is provided with a downwardly which the lever arm between pivot and the actuator for the lower shoe is approximately one-half the lever arm between said pivot and the actuating mechanism for the horizontal shoe. Another object is to provide an independent manual adjustment for each of the steadyrest shoes whereby the position of the shoes relative to the actuating cross arm may be independently adjusted.

Other objects will be in part obvious or in part pointed out hereinafter.

In the accompanying drawings in which is shown one of various possible embodiments of the mechanical features of this invention,

Fig. 1 is a side elevation of the improved steadyrest having parts broken away and shown in section to show the operating parts thereof;

Fig. 2 is a plan view of the steadyrest shown in Fig. 1; and

Fig. 3 is a fragmentary front elevation of the steadyrest, with parts broken away to show the hydraulic motor for actuating the steadyrest shoes.

A steadyrest has been illustrated in the drawings extending integral arm 37 which is arranged in the path of a slide rod 38. The slide rod 38 is slidably keyed within a cylindrical aperture 39 formed in the steadyrest base 10. A manually operable rotatable screw 40 is screw threaded into the left hand end of the slide rod 38. The left hand end of the screw shaft passes through a slidably mounted sleeve 41 which is keyed within the left hand end of the aperture 39. An integral flange 42 on the feed screw 40 and a collar 43 at the other end of the sleeve 41 serve to take up the end thrust of the feed screw shaft relative to the sleeve 41. A manually operable adjusting knob 44 is mounted on the left hand end of the feed screw shaft 40 and serves to facilitate a manual adjustment of the shoe 26 relative to the sleeve A suitable hydraulically actuated mechanism is provided including a single fluid motor which is operatively connected to move the lower or pivotally mounted shoe and thereafter the horizontal shoe into supporting engagement with the work piece to be ground. This mech- 3 is pivotally supported therein by a stud 55 fixedly mount-- ed on the enlarged portion 52 of the slide rod 50.

The cross arm 54 is operatively connected with the

sleeves

30 and 41 for moving the work steadying shoes and 26. The relatively short lower arm of the cross arm 54 is provided with an integral gear segment 56 which meshes with rack teeth 57 formed on the periphery of the sleeve 41 so that the shoe 26 is moved into engagement with the work piece. The relatively long upper arm of the cross arm 54 is provided with a gear segment 58 which meshes with rack teeth 59 formed on the sleeve so that the horizontal shoe 25 is moved into engagement with the work piece after the lower shoe 26 is in supporting engagement therewith. The cross arm 54 extends through a vertical slot 60 formed in the steadyrest frame which is rectangular in shape. The lever arm between the axis of the stud 57 and the gear segment 56 is preferably approximately one-half the lever arm from the axis of the stud 55 to the gear segment 58 so that when the slide rod 50 is moved in a manner to be hereinafter described, the pivotally mounted shoe is first moved into operative engagement with the work piece to be ground with a greater pressure than that applied to the horizontal shoe 25 so as to provide adequate steadying support for a crankpin 23 against the thrust of the grinding wheel 20 during a grinding operation. The greater pressure of the steadyrest shoe 26 serves to exert a thrust on the crankpin being ground tending to raise the shaft and to support it against the downward thrust of the rotating grinding wheel. The movement of the cross arm 54 toward the right (Fig. l) imparting a feed movement to the

shoes

25 and 26 is limited by a pair of stop surfaces 61 and 62 formed at the right hand end face of the vertical slot 60.

A hydraulically operated mechanism is provided for adjusting the slide rod 50 comprising a rotatable feed screw 65 which is screw threaded into the left hand end of the slide rod 50. The feed screw 65 is supported in anti-friction bearings 66 carried by the steadyrest base 10. The feed screw shaft 65 is provided with a pinion I 67 at its left hand end which meshes with a gear 68 mounted on the left hand end of a rotatable shaft 69. The shaft 6% is journalled in spaced

anti-friction bearings

70 and 71. The shaft 69 is provided with a pinion 72 which meshes with rack teeth formed on a piston 74 (Fig. 3) which is contained within a cylinder 75. It will be readily apparent from the foregoing disclosure that when fluid under pressure is passed through a pipe 76 into a cylinder chamber 77, the piston 74 will be moved upwardly to impart a counter-clockwise rotation to the pinion 67 (Fig. 3) and also to the feed screw 65' to iove the slide rod 50 toward the right until the cross arm 54- moves both of the shoes into operative supporting engagement with the crankpin 23 to be ground. During this upward movement of the piston 74, fluid within a cylinder chamber 78 may exhaust through a pipe 79.

Similarly when it is desired to retract the

steadyrest shoes

25 and 26, to an inoperative position, fluid under pressure is passed through the pipe 79 into cylinder chamber 73 to cause a downward movement of the piston 74 thereby rotating the feed screw 65 in the opposite direction so as to move the slide rod 50 toward the left thereby moving the cross arm toward the left to Withdraw the work

steadying shoes

25 and 26 to inoperative positions.

In setting up the improved steadyrest, a work piece of the desired and predetermined size is mounted in position in the grinding machine after which fluid under pressure is passed through the pipe 76 to move the cross arm 54 toward the right until it engages the stop surfaces 61 62. Then by manipulation of the

knobs

33 and 44, the

steadyrest shoes

25 and 26 may be adjusted into supporting engagement with a work piece of the desired and predetermined size. After this setting up operation has been completed, fluid under pressure may be reversed and passed through the pipe 79 to retract the

steadyrest shoes

25 and 26 to an inoperative position. A work piece to be ground may then be mounted in the machine after which fluid under pressure may be passed through the pipe 76 to impart a rotary motion to the feed screw 65 to start the slide rod 50 moving toward the right. Due to the difference in the lever arms of the cross arm 54, the steadyrest shoes will be moved into operative supporting engagement with the work piece to be ground so that the lower steadyrest shoe 26 bears against the work piece with approximately twice the pressure of the horizontally adjustable steadyrest shoe 25. Fluid under pressure is maintained Within the pipe 76 during the entire grinding operation. The forward movement of the

steadyrest shoes

25 and 26 continues until the cross arm 54 moves into engagement with both the stop surfaces 61 and 62 at which time the work piece has been ground to the desired and predetermined size.

As shown in Fig. l a work positioning mechanism is provided for axially positioning a work piece to be ground. This mechanism comprises a bracket fastened to the steadyrest base 10. The bracket 85 supports a vertical shaft 86 in a pair of spaced bearings 8'7 and 38. The upper end of the shaft 86 is provided with a head 89 having a pair of upwardly extending lugs 90 and 91 which are provided with cam faces 92 and 93 respectively. The lugs 90 and 91 are spaced apart by a sufficient distance as illustrated in Fig. 2 so that they do not interfere with the normal operation of the steadyrest shoe 26.

The steadyrest is also provided with a pivotally mounted feeler arm 103 which is provided with a work engaging shoe 104. The feeler arm 103 is pivotally supported by the stud 36. The feeler arm 103 is provided with a downwardly extending portion which is arranged in the path of a slide rod 105. The slide rod 105 is journalled in

bearings

106 and 107 formed within the steadyrest base 10. A compression spring 110 serves normally to exert a pressure on a collar 109 fastened to the rod 105 so as to maintain the right hand end of the rod 105 in operative engagement with the feeler arm 103. The left hand end of the rod 105 is arranged to engage an actuating roller 111 of a limit switch 112 which may be utilized to control other functions of the machine. This work positioning mechanism is more fully disclosed in my co-pending application, Serial No. 450,603, filed August 18, 1954, which issued as Patent No. 2,723,504, November 15, 1955.

The operation of the improved steadyrest will be readily apparent from the foregoing disclosure. In setting up the steadyrest, a work piece which has been finished ground to the desired predetermined diameter is placed in position on the machine, fluid under pressure is then passed through the pipe 76 to cause the slide rod 50 to move toward the right until the cross arm 55 engages the stop surfaces 61 and 62 formed on the steady rest base. Then by manipulating the manually

operable knobs

33 and 44, the steadyrest shoes 25 and 26 are advanced into operative supporting engagement with the periphery of the finished ground work piece. Fliud under pressure may then be reversed and passed through pipe 79 to cause the slide rod 50 to move toward the left to an inoperative position to facilitate loading a work piece to be ground. After this initial set-up, it is merely necessary to admit fluid under pressure through the pipe 76 to cause the

shoes

25 and 26 to move into operative supporting engagement with the periphery of the work piece to be ground. Fluid under pressure within the cylinder chamber 77 serves to advance and maintain the shoes in engagement with the periphery of the work piece being ground as it is reduced in size due to grinding. The advancing movement of the steadyrest shoes 25 and 26 will continue until the cross arm 54 moves into engagement with both the stop surface 61 and the stop surface 62 which serves positively to omit the advance movement of the work steady shoes.

It will thus be seen that there has been provided by this invention apparatus in which the various objects hereinabove set forth together with many thoroughly practical advantages are successfully achieved. As many possible embodiments may be made of the above invention and as many changes might be made in the embodiment above set forth, it is to be understood that all matter hereinbefore set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

I claim:

1. In a grinding machine steadyrest having a base, a horizontally slidable work steadying shoe thereon, a pivotally mounted work steadying shoe on said base, a slide rod to actuate said latter shoe, a pivot stud movable in a direction normal to its axis, a cross arm pivotally supported thereon having a long arm operatively connected to move the horizontal shoe and a short arm operatively connected to move the pivotally mounted shoe, said long and short arm connections serving when the pivot stud is moved to first move the pivotally mounted shoe in operative supporting engagement with the workpiece to be ground at a predetermined pressure after which the horizontal shoe moves into engagement with the work at a lower pressure, and means including 'a piston and cylinder on said base operatively connected between the base and the pivot stud to move said pivot stud in a direction normal to its axis simultaneously to move said shoes into and away from operative supporting engagement with a work piece to be ground.

2. In a grinding machine steadyrest, as claimed in claim 1, in combination with the parts and features therein specified of a stop surface on said base positively to limit movement of said cross arm so as to determine the final position of said shoes, and means including an independent nut and screw mechanism to facilitate an independent adjustment of the work steadying shoes relative to the cross arm.

3. In a grinding machine steadyrest, as claimed in claim 1, in combination with the parts and features therein specified of a slidable member to support said pivot stud which is arranged to slide parallel to the horizontal shoe and the slide rod, a pair of spaced stop surfaces on said base to determine the final position of the opposite ends of said cross arm and means including an independent nut and screw mechanism to facilitate an independent adjustment of the work steadying shoes relative to the cross arm.

4. In a grinding machine steadyrest having a base, a horizontally slidable work steadying shoe thereon, a

pivotally mounted work steadying shoe on said base, a slide rod to actuate said latter shoe, a pivot stud on said base movable in a direction normal to its axis, a cross arm pivotally supported thereby having a long arm operatively connected to move the horizontal shoe and a short arm operatively connected to move the pivotally mounted shoe, said long and short arm connections serving when the pivot stud is moved in a direction normal to its axis to first move the pivotally mounted shoe into operative engagement with the work piece at a predetermined pressure and thereafter to move the horizontally movable shoe into an operative position at a lower pressure, and means including a nut and screw mechanism operatively connected between the steadyrest base and the pivot stud to move said stud in a direction normal to its axis simultaneously to move said shoes into and away from operative supporting engagement with the work piece to be ground.

5. In a grinding machine steadyrest having a base, a horizontally slidable work steadying shoe thereon, a pivotally mounted work steadying shoe on said base, a slide rod on said base to actuate said latter shoe, a pivot stud movable in a direction normal to its axis, a cross arm pivotally supported thereby having a long arm operatively connected to move the horizontal shoe and a short arm operatively connected to move the pivotally mounted shoe, said long and short arm connections serving when the pivot stud is moved to first move the pivotally mounted shoe into operative engagement with the Work piece at a predetermined pressure and thereafter to move the horizontally movable shoe into an operative position at a lower pressure, means including a nut and screw mechanism operatively connected to move said stud in a direction normal to its axis, and means including a piston and cylinder on said base operatively connected to actuate said nut and screw mechanism simultaneously to move said shoes into and away from operative supporting engagement with a work piece to be ground.

References Cited in the file of this patent UNITED STATES PATENTS