US2328251A - Index mechanism - Google Patents

Description

Patented Aug. 31, 1943 INDEX MECHANISM Harold E. Balsiger, Waynesboro, Pa., assignor to Landis Tool Company, Waynesboro, Pa.

Application December 30, 1940, Serial No. 372,223

7 Claims.

This invention relates to machine tools, particularly grinding machines of the type used to grind selected portions of a work piece. Such a machine is disclosed in Ott et al., Patent Number 2,105,841, granted January 18, 1938.

An object of the invention is to provide means for grinding. selected portions of a work piece automatically.

A further object is to provide means for grinding said portions automatically in any desired order.

Figure 1 is a diagrammatic layout of the parts essential to the operation of the invention.

Figure 2 is a closeup elevation showing the arrangement of the pivoted dog, plunger and switch.

In previous machines of the type disclosed, such as that shown in the above mentioned Patent 2,105,841, an end hearing was usually ground first and th others followed in regular order. Recently it has been found desirable in some cases to vary the order of grinding depending upon the conditions peculiar to each case. For example, in grinding the piece shown, rests are used only on the center portions. If the number one portion had been ground first, it would be tapered, out of round, and full of chatter due to distortion of the shaft for lack of support. By starting the grinding operation on the number two portion, the shaft may be supported right from the start and the above mentioned troubles avoided. The number three portion is then ground while being supported by the second rest. With the two center portions ground to size and supported by rests, the grinding on the remaining portions may be done without danger of distortion.

In order to accomplish this a conventional indexing device is used consisting of a notched bar and plunger. Applicant has considered a number of ways by which the order of grinding can be controlled. The method shown herein has been selected for disclosure because of its simplicity. It consists in mounting pivoted dogs adjacent each notch or in some predetermined relation thereto. A switch to be actuated by said dogs is mounted on the bed of the machine and connected to permit or prevent the engagement of the plunger with the notches in the spacing bar. The dogs are pivoted to rotate in one direction only being locked against rotation in the opposite direction. .The direction in which a dog may rotate depends upon whether or not the portion of the work correspondin to said dog is to be ground during the progress of the work carriage in that direction.

The reverse of this arrangement would be just as satisfactory, that is, where a rigid dog is mounted on the spacing bar and engages a series of switches each actuated by a device similar to a pivoted dog.

Thi invention is not limited to the structure disclosed. The arrangement shown in the drawing and described in the specification has been selected for disclosure principally because of its simplicity. Therefore, the scope of the invention is limited only by the appended claims.

In the drawing, numeral l indicates the bed of a grinding machine, II a work carriage slidablymounted thereon, l2 a headstock and I3 a footstock on said carriage, and It a work piece rotatably supported on head and footstock centers l5 and I6 respectively, and having spaced portions I, 2, 3, and 4 to be ground. A grinding wheel I1 is mounted and actuated in a manner similar to that disclosed in the above mentioned.

patent.

A hydraulic motor consisting of pistons and 2| slidably mounted in cylinders 22 and 23 respectively, provides longitudinal reciprocating motion for said carriage. Fluid under pressure is supplied to said motor from a pressure operated reversing valve 25 thru passages 26 and 21. Said reversing valve is actuated by fluid directed to opposite ends thereof thru passages 30 and 3| by valve 32. Said valve is actuated in one direction by a spring 33 and in the opposite direction by a solenoid 34.

Fluid under pressure is supplied to valve 32 from a pump thru passage 4|, valve 42, and passage 43. Valve 42 is actuated by pressure in one direction and by a spring 45 in the opposite direction. Fluid under pressure for operating said valve 42 is supplied to one end thereof from a valve thru passage 5|. Said valve is actuated in one direction by a spring 52 and in the opposite direction by a solenoid 53 acting thru a bell crank 54 in contact with the stem 55 of said valve. An exhaust passage is connected to all of the above described valves for carrying oif exhaust fluid and drainage therefrom. The means for moving footstock center I6 toward and from operative position consists of a piston slidably mounted in a cylinder 66 formed in the footstock l3. Said piston may be actuated in one direction by fluid under pressure and in the opposite direction by a spring 61. Fluid under pressure for operating said footstock is controlled by a valve 68 which receives said fluid from passage 43 and directs same thru passage 59 to rootstock cylinder 66. Valve 68 is actuated in one direction by a spring 10 and in the other direction by a lever II having a roller I2 in the lower portion thereof for engaging a cam surface 13 on the stem I4 of valve 88.

The circuit for controlling solenoid 53 includes a normally closed sizing device or timer relay 88 and a normally open limit switch 8 I.

The means for stopping the carriage II! with the portion of the work to be ground in grinding position consists of a spacing bar 85 having a series of notches 86, 81, 88, and 88 formed therein. At each end of said bar is a stop 88 and 8| for positively limiting the movement of the carriage. Adjacent each notch is a pivoted dog 82, 83, 84, and 85. Pins 86, 81, 88, and 88 are inserted in bar 85 beside each dog so as to prevent rotation of said dog in one direction. Dog 82 is held against rotation in a clockwise direction. Dogs 83, 84, and 85 are held against rotation in a counterclockwise direction. Obviously said dogs may be arranged in any sequence for clockwise or counterclockwise rotation depending on the order in which the several portions of the work are to be ground. A plunger I88 is pivotally attached to engages switch 8|. Saiddog is locked against rotation during movement to the left, and, therefore, switch 8| is closed, solenoid 53 is energized, and valve 58 depressed to connect passage to the exhaust passage 88. Spring 45 then urges valve 42 and plunger I88 upwardly, said plunger engages notch 81 and stops carriage I in position to grind portion 2.

an intermediate portion of an arm I8I. One end of said arm is pivotally attached to the bed I 8 Operation The grinding operation is started with the grinding wheel I'I near the headstock end of the carriage I I. Plunger I88 is in withdrawn position adjacent end stop 88. Valve 42 is in the downward position so that fluid under pressure from supply passage 4| and pump 48 is directed thru passage 43 to foot'stock valve 68, pilot valve 32. and reversing valve 25. In the vertical or inoperative position of lever II, valve 68 is depressed and connects passage 68 with the supply passage 43. Fluid under pressure is thus conducted to cylinder 66 where it shifts piston 65 against spring 61 to hold footstock center l5 in retracted position. After the operator inserts a work piece in the maclhne, he shifts lever II to the right releasing valve 68 and connecting passage 68 with exhaust passage 68. Spring 61 then moves center I6 into engagement with the work piece l4. Valves 32 and are at this time in position to cause fluid under pressure tobe directed thru passage 21 to move the carriage from left to right,that is, the opposite of the position of said valves in Figure 1. Valve 32 is held in this position by solenoid 34. In order to start the traverse movement, the operator depresses push button stop switch I I2 thus deenergizing solenoid 34 and permitting spring 33 to shift valve 32 to the position shown in Figure 1. In this position of valve 32, fluid under pressure from passage 43 is directed thru valve 25 to passage 21 to shift pistons 28 and 2| with carriage II from left to right. Normally, plunger I88 would drop into notch 86 to stop the carriage in position to grind portion I. However, in order to release said plunger the circuit to solenoid 53 must be closed as shown in Figure 1. Switch 8| in said circuit is normally open, but may be closed by one of the pivoted dogs 82, 83, 84, or 85. Dog 82 is pivoted so that it is free to rotate when engaged by the roller of switch 8| during movement of the carriage to the left. Therefore, solenoid 53 remains-deenergized,

valve 58 is held by spring 52 in position to direct fluid under pressure from passage 4| thru passage 5| to hold plunger valve 42 and plunger I88 in the downward position. Thus, the grinding operation on portion I is omitted at this time. The carriage movement continues until dog 83 The grinding operation on this type of machine may be controlled by a sizing device as disclosed in Patent No. 2,185,841 referred to above, or by a timing mechanism as shown in Serial No. 220,777, filed July 22, 1938, which became Patent No. 2,243,418, May 27, 1941. In either case the control device would function thru a relay contact 88, in this case normally closed, so that when the relay is energized by the size control device the circuit to,solenoid 53 is broken and said solenoid deenergized, valve 42 depressed, and plunger I88 withdrawn. Valve 42 then directs fluid under pressure from passage 4| thru passage 43 to the traverse control valves 25 and 32 to move carriage I to the next position.

Dogs 84 'and 85 are arranged to stop the carriage for portions 3 and 4. After portion 4 has been ground the movement of the carriage to the left is continued. This movement may be terminated either by an end stop 8| engaging plunger I88, in which case the carriage remains stationary until started manually in the opposite direction, or a dog 8 may engage a switch III to complete a circuit from line LI thru said switch and a stop switch I I2 to energize solenoid 34. At the same time relay 5 is energized to complete a circuit thru contact I I6 bypassing both switches to energize solenoid 34. After release of said switches said relay is held thru said contact II6. Said solenoid then shifts valve 32 against spring 33 to direct fluid under pressure from passage 43 thru passage 38 to shift valve 25 to the downward position. Valve 25 then directs said fluid from passage 43 thru passage 26 to the left end of cylinders 22 and 23 to move pistons 28 and 2| and carriage from left to right. During movement from left to right, dogs 83, 84, and 85 will not close switch 8|. Therefore, the carriage will not stop at the positions corresponding to these dogs. Dog 82 is arranged to close said switch during movement from left to right and the carriage is thus stopped in position to permit the grinding of portion I. When this portion has been ground to size, solenoid 53 is deenergized thru size control contact 88 and the carriage moved to the right until end stop 88 engages plunger'l88 and stops the carriage for unloading and loading. Lever II is shifted to the vertical position depressing valve 68 and directing fluid under pressure thru passage 68 to footstock cylinder 66 to retract center I6 from the work.

The sequence of operation disclosed, i. e., grinding the intermediate portions of the work piece first and thereafter grinding the end portions, has been found very effective for attaining accuracey in one orboth of the end portions. By

support, mechanism for efiecting a relative longi-,

tudinal movement between said tool and said work support, means for initiating said longitudinal movement intermittently for positioning said tool and successive portions of a work piece, an indexing-mechanism for controlling said positioning means, and means for omitting predetermined portions during the operation of said indexing mechanism including stopping devices which are operable only during said longitudinal movement in one direction.

2. In a metal working machine, a tool, a work support, mechanism for effecting a relative longitudinal movement between said tool and said work support, mean for initiating said longitudinal movement intermittently for positioning said tool and successive portions of a work piece, an indexing mechanism for controlling said positioning means, means for omitting predetermined portions during the operation of said indexing mechanism, and for'thereafter relatively positioning said tool at said omitted portions.

3. In a metal working machine, a tool, a work support, mechanism for efiecting a relative longitudinal movement between said tool and said work support, means for initiating said longitudinal movement intermittently for positioning said tool and successive portions of a work piece including a size control mechanism, an indexing mechanism actuated by said size control mechanism for controlling said positioning means, and means for selecting predetermined portions for machining during the operation of said indexing mechanism including stopping devices which are operable only during said longitudinal movement in one direction.

4. In a metal working machine, a tool, a work support, mechanism for effecting a relative longitudinal movement between said tool and said work support, means for initiating said longitudinal movement intermittently for positioning said tool and successive portions of a work piece including a spacing bar having spaced notches corresponding to the said portions of the work piece, a plunger for engaging said notches, and means for preventing engagement of said plunger with certain of said notches.

5. In a metal working machine, a tool, a work support, mechanism for effecting a relative longitudinal movement between said tool and said work support, means for initiating said longitudinal movement intermittently for positioning said tool and successive portions of a work piece including a spacing bar having spaced notches corresponding to the said portions of the work piece, a plunger for engaging said notches, and means for causing said plunger to engage said notches in any predetermined sequence.

6. In a metal working machine, a tool, a work support, mechanism for efiecting a relative 1ongitudinal movement between said tool and said work support, means for initiating said longitudinal movement intermittently for positioning said tool and successive portions of a work piece including a spacing bar having spaced notches corresponding to the said portions of the work piece, a plunger for engaging said notches including a pivoted dog adjacent each of said notches, and a switch actuated by each of said dogs during movement of the carriage depending upon the direction of said movement for controlling withdrawal of said plunger.

'7. In a metal working machine, a tool, a work support, mechanism for efiecting a relative 1ongitudinal movement between said tool and said work support, means for initiating said longitudinal movement intermittently for positioning said tool and successive portions of a work piece including a spacing bar having spaced notches corresponding to the said portions of the Work piece, aplunger for engaging said notches including a pivoted dog adjacent each of said notches, and a switch actuated by some of said dogs during movement of said carriage in one direction and by other of said dogs during movement of said carriage in the other direction for controlling withdrawal of said plunger.

HAROLD E. BALSIGER.

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