US2521979A

US2521979A - Size controlling apparatus

Info

Publication number: US2521979A
Application number: US679128A
Authority: US
Inventors: Theodore A Jagen
Original assignee: Motors Liquidation Co
Current assignee: Motors Liquidation Co
Priority date: 1946-06-25
Filing date: 1946-06-25
Publication date: 1950-09-12
Anticipated expiration: 1967-09-12

Description

Sept. 12, 1950 T. A. JAGEN SIZE-CONTROLLING APPARATUS Filed June 25, 1946 G MM A m MA MW E Z Patented Sept. 12, 1950 SIZE CONTROLLING APPARATUS Theodore A. Jagen', Harrison, N. J., assignor to General Motors Corporation, Detroit, Mich, a corporation of Delaware Application June 25, 1946, Serial No. 679,128

11 Claims.

This invention relates to size controlling apparatus and particularly to gauging apparatus arranged to measure the size of an article and to control a machining operation such as a grinding operation on the article.

An object of the invention is to provide an improved and simple gauging apparatus which controls the grinding of a work piece.

Another object is provide an improved sizecontrolling apparatus wherein electrical mechanism, responsive to a gauge which visually indicates the size of a work piece durin grinding, operates to terminate the grinding operation when the gauge indicates a predetermined work-size.

Another object is to provide an electronic grinding feed control which is responsive to a gauge that measures the change in size of a work piece during a grinding operation.

To these ends and also to improve generally upon devices of the character indicated, the invention consists in the various matters hereinafter described and claimed. In its broader aspects, the invention is not necessarily limited to the specific constructions selected for illustrative purposes in the accompanying drawings wherein:

Figure 1 is a fragmentary end view of a grinding machine including a diagrammatic showing of the electrical circuits and illustrating the operation of the invention;

Figure 2 is a front elevation of the work gauging mechanism;

Figure 3 is an enlarged fragmentary sectional view taken substantially along the line 33 of Figure 2;

Figure 4 is a fragmentary view of one type of dial gauge used in this invention;

Figure 4a shows one form of a pointer contactor mounted in position;

Figure 5 is a front elevation of a dial gauge provided with another form of a pointer contactor; and

Figure 6 is a cross section taken substantially along the line 6-6 of Figure 5.

Generally considered, a machine tool such as a grinding machine has its tool feeding orgrinding wheel feeding mechanism responsive to a work sizing apparatus that includes a calipertype gauge l0 provided with a dial gauge, as H, whose movable pointer [2 indicates with respect to a suitable index or dial graduations the extent of change in size of a work piece W being ground. When this work piece is ground to the desired predetermined size, the pointer l2 engages a contaotor, as it, causin electronic control mechanism to control the feeding mechanism and terminate the grinding operation.

In the illustrated embodiment, the size controlling apparatus is applied to a grinding machine having a base I5 upon which is slidably mounted a work table 16 arranged to support the work piece W for rotation and axial reciprocation, and a rotatable grinding wheel I! is fed transversely towards and from the work piece by a wheel slide 58 slidably mounted on the base. The power operated mechanism for feeding the grinding wheel towards and from the grinding zone may comprise a cylinder 2% fastened to the base l5 and containing an axially slidable piston 22 which is operatively connected to the wheel slide [8 through a piston rod 23 that is slidable through a cylinder head. The direction of wheel feedin movement is controlled by a reversing valve 25 having three spaced

pistons

26, 27 and 28 slidable in a cylinder 30 under control of an axially shiftable piston rod 32 that slidably extends through an end of the reversing valve.

When the reversing valve pistons are in their illustrated full line positions, fluid under pressure from a pipe 33 enters the cylinder 30 between the pistons 21, '28 and flows out through a pipe 34 into the rearward end of the cylinder 20 causing a forward movement of the piston 22' which results in a feeding of the grinding wheel towards'and into the work piece W. Fluid from the forward end of the cylinder 20 now exhausts through a pipe 35 into the cylinder 36 between the pistons 26, 2! and out through an exhaust pipe 36 and through a throttle valve 37 which is adjusted to control the rate of grinding wheel feed. When the reversing valve pistons are shifted to their dot-dash indicated positions as by a manual shift member 38, or by a solenoid 46' to be later described, fluid under pressure from the pipe 33 flows between the piston 25, 21 and through the pipe 35 into the forward end of the cylinder 20 causing arearward movement of the piston 22 with a consequent withdrawal of the grinding wheel away from the work piece W. This Withdrawal of the grinding wheel will be much more rapid than the grinding wheel infeed since the fluid from the rearward end of the cylinder 2t now will exhaustfreely through the pipe 34, between the pistons 21, 28 and out through an exhaust pipe 42.

The caliper gauge Hi, which may be of the Arnold type, has a main frame t3 that slidably receives a generallyvertical gauge plunger 44 wheel, at the other end pivotally supports a bracket 50 which grips a dovetailed rearward portion of the upper end of the main frame 43. A housing 52, fastened to the wheel slide 18, pivotally supports the lower end of the arm 48, and

spring mechanism within this housing is regu-- lated to swing the arm 48 upwardly with sufiicient pressure to overcome the weight of the gauge assembly [0 and maintain the hardened contact on the finger in light engagement against the underside of the work piece W during gauging. The gauge assembly H1 is located sufficiently forwardly of the pivotal mounting for the bracket 50 to cause the gauge to swing towards the work piece and maintain the hardened contact of the finger 45 in light engagement with the work piece during gauging.

The dial gauge H has a casing 53 from which projects an axially slidable stem 54 urged outwardly from the casing as by a spring 55, and connected through amplifying mechanism, as a rack portion 55 and gears 51, 58 and 59, to position the pointer l2 with respect to a graduated gauge dial. The upper end of the plunger 44 has a head 82 (Fig. 3) slidably mounted in the main frame 43 and urged downwardly by a spring pressed arm 63 whose downward movement is limited by a stop screw 64 to prevent injury to the dial gauge. A dovetailed projection 55 on the underside of the dial gauge and parallel to 1 the gauge stem 54 slidably fits within Ways on a laterally extending main frame projection 66 to angularly support the dial gauge conveniently to the machine operator. The movable gauge stem 54 extends through an aperture in the main frame and has a rounded end which engages an overlying reentrant face 61 on the head 52. A vertical movement of the plunger 44, in response to a change in size of the work piece during grinding, causes a movement of the face 61 resulting in a movement of the gauge stem 54- and a consequent measurement of change in work size by the pointer on the graduated gauge dial. A plate 58 having an upwardly projecting lug fitting within a recess in the gauge casing has at each end a slot through which extends a screw Hi threaded into the frame projection 65. A stud 'll journalled in this frame projection 66 and having an eccentric head may be turned to longitudinally shift the plate 68 and axially position the gauge stem 54 for initially adjusting the gauge pointer position with respect to they movable plunger 44 after which the screws 10 may be tightened to maintain this adjustment.

A crystal (3 of plastic or other suitable transparent insulating material, throughwhich the pointer position may be observed, is gripped by a bezel l4 threaded or otherwise rotatably mounted on the casing 53. The contactor 13, which may be of suitable electro-conductive metal as brass, is shown as a stud projecting inwardly from the crystal sufiiciently to be engaged by the pointer i2, this stud being held in position by a screw 75 passing through a hole in the crystal. The dial gauge is preferably of the 4 shockproof type as shown in Figure 4 wherein-inward movement of the stem 54 causing a clockwise pointer movement, as viewed in Figure 2, will not be injurious to the gauge after the pointer stops against the contactor l3. As illustrated, the coaxial gears 51 and 58 are not positively connected and an arm 16 secured to the gear 58 is engageable with an arm 11 secured to the gear 51. A helical spring tends to rotate the gear 58 to position the arm 16 against the arm 11. When the clockwise pointer movement, as viewed in Figure 2, is stopped by the contactor IS, the gear 58 and the arm 16 remain stationary while further inward movement of the stem 54 only causes the arm "H to retreat from the arm 16.

In the event that the dial gauge does not embody the"shockproof mechanism of Figure 4, I employ a hairspring contactor arrangement as shown in Figures 5 and 6 which permits the pointer 12 to swing past contact-making position without causing damage to .the dial gauge. A helical hairspring I8 of suitable elec tro-conductive metal is axially secured between the crystal l3 andthe pointer l2 by a stud 8U fastened through the crystal. A generally radially extending hairspring arm 82 is urged counterclockwise by the hairspring against a stop 83 that may be similar to the contactor I 3 but which does not project into a pointer engaging position. An inwardly projecting hairspring end 84 is intercepted by and makes electrical connection with the pointer when the pointer swings to a position beneath the stop 83. Due to the resiliency of this light hairspring, the pointer may swing past this stop 83, while contacting the hairspring.

A stop 85, which also may be similar in construction to the contactor i3, is fastened through the crystal 13 to the right of the contactor H3 or to the right of the hairspring end 84, to prevent the pointer l2 from swinging counterclockwise into a circuit making position. The bezel 14 is rotatably adjusted to locate this circuit making position of the pointer 12 and is fastened in this adjusted position by a clamping screw 86.

The mechanism of a dial gauge is delicate, and the pointer as well as other small parts would be ruined by any strong flow of electricity therethrough. Hence, I employ an electronic control device wherein the extremely minute current flow in the grid circuit of an electronic vacuum valve passes through the pointer 12 and the contactor I3 or the hairspring 18. One satisfactory electronic control circuit which has been found successful, includes an electron tube such as a three element vacuum valve 81, having a filament or cathode F heated by a battery A; a grid G and a plate P. The coil of a normally open-circuit relay 88 is connected in series between the plate P and the positive terminal'of a battery B; The contactor l3 or the hairspringstud Bll'is connected by a wire 90 to the grid G and'to one end of a-current limiting resistor Rwhose other end is connected to the negativeterminal of a grid.

bias battery C whose positive terminal is connected to the negative terminals of batteries A and B. To complete the grid circuit to the point-, er, the pointer is grounded through the casing 53 and a ground wire 91 is connected to the negativeterminal of the battery A.

vIn operation, while the caliper type gauge I 0 is located on theavork piece during grinding and;

prior to circuit making position of the pointer 12, the grid bias battery C maintains the grid G negative andn'o current flows in the plate circuit through the relay 88 which is normally in open circuit. When the work piece is reduced to desired predetermined size, the pointer l2 engages the contactor 13 or the hairspring end 8d thereby causing the grid G to be at cathode potential. This results in current flow in the plate circuit and: energizes the relay 88 which closes a power circuit through

wires

92 and 93 causing the solenoid 40 to become energized and act through an armature fi l-to shift the reversing valve pistons to their dot-dash indicated reverse positions. This electronic control is extremely sensitive and rapid acting causing the grinding wheel to immediately withdraw from grinding position when the pointer l2 reaches circuit closing position which corresponds withthe pointer measurement of desired work size. When the caliper gauge assembly is removed from the work piece W, the pointer 12 swings counterclockwise to a stop position against the stop 85 and the grid G again becomes negative causing a cessation of current flow in the plate circuit and deenergizing the re lay 88 which breaks circuit to the solenoid The succeeding grinding feed is started by operating the manual control member 353 to shift the reverse valve pistons back to their full line indicatedpositi-ons.

I claim:

1. In a work sizing apparatus for controlling the feeding of a grindin wheel into a work piece to reduce the size of the work piece, gauging mechanism including a movable contact member engageable with the work piece during grinding, a dial gauge having a pointer in said mechanism movable over a graduated scale in response to the movable contact member to measure the size of the work piece, a contactor arranged to be engaged by the pointer for closing a circuit when said pointer reaches a predetermined position of its movement, and electronic feeding control mechanism including an electron tube responsive 'to the closing of said circuit to control a stop of said grinding wheel feed.

2. In a work sizing apparatus, a dial gauge having a pointer movable over a graduated scale on a dial for measuring the size of a work piece, a contactor mounted on said gauge independently of said dial and in a position to be engaged by the pointer when the pointer is moved in one direction to a predetermined position, a member preventing the pointer from moving in an opposite direction into engagement with said contactor, means to simultaneously adjust said contactor and said member to predetermined positions with respect to said graduated scale, and electrical connections to the pointer and to the contactor whereby movement of the pointer into and out of contactor engagement may control an electrical circuit.

3. In a work sizing apparatus, a dial gauge having a pointer movable over a graduated scale on a dial for measuring the size of a Work piece, a transparent crystal mounted on the gauge for rotatable adjustment adjacent to said dial, means to secure the crystal in rotatably adjusted posi tion, a contactor secured to the crystal and having a portion arranged to be engaged by the pointer when the pointer is moved in one direction to a predetermined but adjustable position with respect to the scale graduations, electrical connections to the pointer and to the contactor whereby the movement of the pointer into and out of contactor engagement may control an electrical circuit, and means stopping the reversed 6 rotation of said pointer at a predetermined dis-' tance from said contactor irrespectiveof the adjusted position of said contactor.

4. In a work sizing apparatus, a dial gauge having a pointer movable over a graduated scale on a dial for measuring the size of a work piece, a transparent crystal adjacent to said dial, a contactor mounted on the crystal in insulated relation to said pointer and in a position to be engaged by the pointer when the pointer is moved in one direction to a predetermined indicating position on the dial, a stop member mounted on the crystal and preventing the pointer from moving in an opposite direction into contactor engagement, electrical connectionsto said contactor and to said pointer whereby pointer movement into and. out of contactor engagement will control an electrical circuit, means to rotatably adjust the crystal for simultaneously positioning the contactor and the stop member at predetermined positions relative to said dia1 graduations, and means to secure said crystal in adjusted position. i

5. In a work sizing apparatus, a dial gauge having a pointer movable over a graduated scale for measuring the size of a work piece, a stop member adjacent to but out of the path of pointer movement, a hairspring mounted in insulating relation to the pointer and 'resilientlyurged into engagement with the stop member, a projection on the hairspring arranged to be engaged by the pointer for closing an electrical circuit, and said hairspring being yieldably movable by the pointer away from the stop member while maintaining electrical contact with the pointer;

6. In a work sizing apparatus, a dial gauge having a pointer movable over a graduated scale for measuring the size of a work piece, a stop member adjacent to but out of the path of pointer movement, a h'airspring mounted in insulating relation to the pointer and resiliently urged into stop member engagement, means to adjustably position the stop member with respect to the graduations of said scale, a projection on the hairspring arranged to be engaged by the pointer for closing an electrical circuit at a predetermined pointer position, and said hairspring being yieldably movable by the pointer away from the stop member while maintaining electrical contact with the pointer.

'7. Ina work sizing apparatus, a dial gauge having a pointer movable over a graduated scale for measuring the size of a work piece, a stop member adjacent to but out of the path of pointer movement, a hairspring mounted in insulatin relation to the pointer and resiliently urged into stop member engagement, means to adjustably position the stop member with respect to the graduations of said scale, a projection on the hairspring arranged to be engaged by the pointer for closing an electrical circuit when the pointer moves in a measuring direction to a predetermined position, said hairspring being yieldably movable by the pointer away from said stop memprovided with a cathode and'a grid and a plate, means connecting the pointer and the contactor in circuit with said cathode and said grid to effect a change in grid bias voltage when the pointor engages said contactor, there being a change in current flow through the plate in response to a change in grid bias voltage, and mechanism responsive to a change in current flow through said plate.

9. In a Work sizing apparatus, a dial gauge having a pointer movable over a graduated scale on a dial for measuring the size of a work piece while the work piece is being ground, a contactor insulated from the pointer and mounted on the gauge in the path of pointer movement, means to adjust said contactor to a predetermined position to be engaged by said pointer, an electron tube provided with a cathode and a grid and a plate, means connectin the pointer and the contactor in circuit with said cathode and grid to effect a change in grid bias voltage when the pointer engages said contactor, means providing a current flow through said plate under control of the amount of grid bias voltage, and

mechanism responsive to the current flowthrough said plate for controlling the extent of a grinding operation on the work piece.

10. In a work sizing apparatus, a dialgauge having a pointer movable over a graduated scale on a dial for measuring the size of a Work piece while the work piece is being ground, a contactor on the gauge in the path of the pointer movement and insulated from said pointer, means to adjust the contactor to a predetermined pointerengaging position, an electron tube provided with a cathode and a grid and a plate, means connecting the pointer and the contactor in circuit with the cathode and grid to efiect a change in grid bias voltage when the pointer engages said contactor, the amount of current fiow through said plate being controlled by said grid bias voltage, and means responsive to a predetermined amount of current flow through said plate for effecting a termination of a grinding operation on the work piece. 1 11. Ina work sizing apparatus, a. dial gauge having a pointer movable over a graduated scale on a dial for measuring the size of a work piece while it is being ground, a transparent crystal adjacent to said pointer, a contactor mounted on the crystal and arranged to be engaged by said pointer, means to rotatably adjust said crystal for locating the contactor at a predetermined pointer-engaging position, an electronic circuit including an electron tube provided with a grid and a plate, means electrically connecting said pointer and said contactor in circuit with the grid to efiect a change in grid bias voltage when the pointer engages said contactor, means providing a current flow through the plate under control of said grid bias voltage, and grinding controlling mechanism responsive to a change in current flow through the plate of said tube.

THEODORE A. JAGEN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS