US2464387A - Grinding gauge for out-of-round pistons - Google Patents

Description

March 15, 1949. s, FOSTER v 7 2,464,387

GRINDING GAUGE FOR OUT-OF-ROUND PISTONS Filed Aug. 13, 1947 w 2 Sheets-Sheet l INVENTOR.

March 15, 1949. s. A. FOS TIERY 2,464,387

GRINDING GAUGE FOR OUT-OF-ROUND PISTONS v Filed Aug. 13 1947 2 Sh eets-Shee t 2 I I mroKNE).

Patented Mar. 15, 1949 GRINDING GAUGE FOR OUT-OF-ROUND PISTONS Shubel A. Foster, Pleasant Ridge, Mich.

Application August 13, 1947, Serial No. 768,359

7 8 Claims.

This invention relates to gages for production grinding, wherein the gaging or checking of the work is done throughout the grinding operation so that simple observance of the progressive movement of an indicator will show when the grinding is completed to the extent desired, whereupon the machine may be stopped either manually, or automatically as by the closing of a machine-controlling circuit, and a new piece of work substituted for that which has just been ground.

Such type of production checking gage is now well known in the grinding industry and has proved both fast and reliable; so that it is an object of the present invention to utilize the advantages of such production type of checking gages under circumstances which have not heretofore lent themselves readily to gaging in the manner referred to, as in the case of work which is intentionally to be ground to an out-of-round, eccentric, oval, elliptical, or similar form wherein the radial dimensions are required, nevertheless, to be accurately assured in the finished work.

A typical example of work, to which the present invention is eminently adaptable, is the presenttype of piston wherein it is a common practice to make the piston wider across one diameter than across another diameter transverse to the first in order that the piston, in use, may accommodate itself to variations in expansion along these two diameters and thus, when heated, more correctly fit and bear on the walls of its cylinder. Generally speaking, the major of these diameters extends in alignment with the piston pin and the minor diameter at right angles to the said pin.

The type of production gage heretofore referred to is characterized b a caliper frame engaging beneath the work and carrying, in a tube extending upwardly of the said frame, a movable gage rod the lower end of which through the medium of a suitable wear-resisting element rides upon the top of the work; the said gage rod being connected with an indicator adapted to show the extent of movement of said rod toward the axis of rotation of the work and thus indicate the progress of the grinding of the work, and/or a circuit controlling switch adapted to terminate the grinding operation when the grindingreaches the point of completion. The gaging device generally described (including the caliper frame, the gage rod, its tube, and indicator) is usually carried by a. spring-mounted swinging arm suitably positioned on the grinding machine whereby the gage may be quickly swung into and out of gaging position.

It will be clear that with such an arrangement it would be possible to gage major, minor, or other diameters of the work during grinding if the indicator were constantly and closely watched and the work were rotated at quite slow speed, but the disadvantages and limitations of gaging the work in this manner will be obvious; and the principal object of the present invention is to provide an arrangement, in such a type of production gage, which will eliminate confusing and unnecessary gaging of all of the peripheral surface of the work except certain points which will be sufilcient to properly indicate the progress of the grinding.

Such point (or points) could be conveniently the high points of major diameter, or they could be the low points of minor diameter, (or even any given points therebetween) due to the fact that the out-of-round form to be ground is a result of mechanical and timed manipulation of the grinding machine itself and is always according to pre-deterrnined pattern which may be controlled by a master cam. The means of producing the out-of-round form is, of course, no part of the present invention.

A further object of the said invention is to provide, in a production grinding gage of the type referred to, means for rendering the gage-rod or element inactive throughout the greater portion of the grinding cycle and to further pro- Videfor presenting moving or permitting the gage rod or element to move into gaging relation to the work periodically and at timed intervals, whereby a certain point, or points, of determined diameter will be regularly checked during rotation and grinding of the work.

Still further objects or advantages additional or subsidiary to the aforesaid objects, or resulting from the construction or operation of the invention as it may be carried into effect, will become apparent as the said invention is hereinafter further disclosed.

In carrying the said invention into efiect, I may adopt the novel construction and arrange ment of parts hereinafter described, by way of example, having reference to the accompanying drawings, wherein:

Figure 1 illustrates a production grinding gage embodying the said invention as applied to a piston being ground;

Figure 2 is a detail elevation of the caliper frame and associated parts of the device shown in work-engaging position, the cam follower being omitted for simplified illustration;

Figure 3 is a side elevation of the arrangement shown in Figure 2 but including the cam follower;

Figure 4 is a similar view to Figure 2 with the caliper and associated parts removed to disclose details of the cam and follower mechanism; and

Figure 5 is a plan of the said follower and the movable jaw of the caliper frame, the said frame being shown in section taken on a plane indicated by the line 55 in Figure 2.

Similar characters of reference indicate similar parts in the several figures of the drawings.

It] indicates the headstock of a grinding machine and II is an adaptor or carrier for the work, which work in this case is a piston 12, the said adaptor being shown as including a cam element [3 tapered at its outer end, as at 14, to enter and locate the skirt of the piston, and a driver E5 in the form of a bifurcated extension to engage the piston pin l6 in the manner which will be quite clear to those familiar with the general grinding art.

It is common to make such pistons oval or out-of-round as indicated in Figure 2 wherein a and b indicate the major and minor diameters which it is intended to grind. The outer end of the piston is usually engaged by a tailstock center (not shown).

The actual grinding of such a piston by the grinding wheel H is controlled by a profiling mechanism (not shown) usually involving a master cam which causes the grinding wheel to move inwardly of the work, or the work inwardly of the grinding wheel, twice during each revolution of the work so that the dimensional relationship of the major and minor diameters is preset; and it is not a function of the production gage about to be described to determine this diameter variation but merely to determine when the grinding has progressed to the finish point wherein a predetermined dimension is secured at a given point in the circumference of the work or piston.

It is convenient to select the high point or points for this purpose, conforming in the illustrated example to the major diameter a.

The gaging device illustrated is characterized by a C-shaped caliper frame 53 provided with a lower shoe 19 to engage beneath the work, as shown, and a laterally disposed shoe 20 to abut one side of the work and thus determine the position of the shoe l3 beneath the work. Extending upwardly from the said caliper frame 18 is a tub-e 2| carrying a vertically reciprocal gage rod 22 which is biased downwardly by a compression spring 23 in the gage head 24.

The upper end of the said rod 22 is notched to provide a shoulder 25 which abuts the plunger 23 of an indicator 2'! for the operation of the said indicator in the manner well known. Details of the indicator itself are not shown or described as being simply a standard mechanism Well understood in the art to which this invention appertains, except to say that the indicator illustrated is provided with a plunger extension 2 8 of the type described in applicants United States Patent No. 2,270,728 granted January 20, 1942, the said extension 28 passing between friction or braking members 29 hearing on opposite sides thereof to retain the indicator plunger in position indicating the smallest diameter perceivable by the gage during its operation, In other words, the indicator is only operated by the downward movement of the plunger and will not reverse its movement of operation except under the influence of manual pressure applied to the lower end of the plunger extension, which is provided with a push button 30 for that purpose.

The gage head 24 and tube 2|, together with parts carried thereby, is hingedly supported on the end of a vertically swingable arm 3|, the inner end of which arm is mounted on a spring housing 32 internally biased by means (not shown) to more or less balance the weight of the arm 3| and parts carried thereby; 33 indicating a support for the spindle of the said spring housing, which sup-port may be attached to any stationary part of the grinding machine which is convenient. The described arrangement admits of the gage mechanism including the caliper frame l8 being swung into and out of operative relation to the work to facilitate unobstructed removal and replacement of work whenever desired.

The cam element E3 of the adaptor H is provided with flats or depressions 34 coinciding with the high points of the piston periphery, as shown; and mounted on the headstock H) of the machine is a bracket 35 carrying a pin 36 on which a follower arm 31 is hingedly mounted for vertical lifting against the resistance of a spring 38. The outer end of the said arm 31 carries a follower roller 3Q positioned to ride the periphery of the said cam element l3 whereby the said follower arm 31 will be slightly depressed by the spring 33 when the roller 39 passes over one or other of the flats 34 of the said cam element. This follower arm 31 has projecting from one side thereof a block 40 provided on its upper surface with an insert 4| of wear-resistant material.

It will be noted that the follower arm 31 is positioned behind the caliper frame l8, as viewed in Figure 1, and this caliper frame carries a similarly swingable caliper jaw 42 which is provided with a shoe 43 beneath its outer free end to rest upon the work when it is so permitted.

However, this movable caliper jaw 42 is provided with a rearwardly extending block 44 which carries a vertically adjustable stop 45 extending over the wear-resistant insert 4| of the cam follower block 43, as clearly shown in Figure 2.

Thus, when the lower end of this stop 45 is closely spaced from the top of the insert 4| with the roller 39 riding one of the flats 34 of the cam element [3, the raising of the follower arm 31, when the said roller leaves such fiat and thereupon travels the cam surface of greater diameter, will cause the said block 40 to strike beneath the stop 45 and thus raise the movable caliper jaw 42. This raising of the jaw 42 causes the shoe 43 thereof to be spaced above the surface of the piston or work as indicated at c in Figure 2.

While the caliper jaw 42 is so raise-d (which is throughout almost the entire cycle of rotation of the work), the gage rod 22 of the gage proper is also raised out of operative contact with the plunger 26 of the indicator 21. It is only through the very brief interval during which the roller 39 traverses one or other of the flats 34 of the cam element that the shoe 43 of the movable caliper jaw is permitted to contact the work and, with' the setting shown, this contact would be limited to the high points in the periphery of Work.

By reason of the braking effect imposed on the plunger extension 28 of the indicator 21, the

only indicating motion transmitted to the indicator mechanism would be that representing the reduced radial distance of the high point of the piston, resulting from the grinding which has taken place since the movable caliper arm was previously released, by the action of the follower arm '21, to perform its checking function. Where this release is effected normally once, or twice, in each revolution of the work, the change in radial dimension would be extremely slight and not readily perceptible to the eye in reading the indicator, but the series of very slight and progressive timed downward movements of the gage plunger 22, resulting from the checking motions of the movable caliper jaw 42, would eventually show that reading on the indicator which would warn that the grinding was complete or close to completion as the case may be.

Figure 1 also shows how the arrangement lends itself to use with an electric gage such as of the type disclosed in United States Patent No. 2,267,- 559 of applicant granted to me December 23, 1941, this being shown schematically and for simplicity in the present drawings as a movable switch plate 46 adapted to close contacts 41 upon the gage plunger descending to the position of complete grinding, whereupon the circuit is closed through the solenoid 48 to open a switch 49 and thereby cut off current through the grinding machine motor l5 to stop further grinding action of the machine to which it is applied.

This invention may be developed within the scope of the following claims without departing from the essential features of the said invention, and it is desired that the specification and drawings be read as being merely illustrative of a practical embodiment of the same and not in a strictly limiting sense.

What I claim is:

1. In a production gage of the type described, in combination, work-rotating means, work calipering means including a movable caliper jaw, a work-checking device, means coupling said device with said jaw for transmitting movements of said jaw thereto to determine completion of the grinding of the work, a cam, and a cam-operated member adapted to move said jaw out of contact with the work except at timed intervals determined by the rotation of said cam.

2. In a production gage of the type described, in combination, work-rotating means, said means including a cam, work calipering means including a movable caliper jaw, a work-checking device, means coupling said device with said jaw for transmitting movements of said jaw thereto to determine completion of the grinding of the work, and a movable jaw actuating member adapted to operation by said cam to move said jaw out of contact with the work except at timed intervals determined by the rotation of said cam.

3. In a production gage of the type described, in combination, work-rotating means, work calipering means including a movable caliper jaw, a work-checking device, means coupling said device with said jaw for transmitting movements of said jaw thereto to determine completion of the grinding of the work, a cam, and a cam-operated member positioned to engage and lift said jaw out of contact with the work except at timed intervals in the rotation thereof.

4. In a. production gage of the type described,

in combination, work-rotating means, work-calipering means including a movable caliper jaw, a work-checking device, means coupling said device with said jaw for transmittin movements of said jaw thereto to determine completion of the grinding of the work, a cam, a movable cam follower, and adjustable means through which lifting of said follower by said cam may be transmitted to said movable caliper jaw.

5. In a production gage of the type described, in combination, work-rotating means, work-calipering means including a vertically swingable caliper jaw, a work-checking device, means coupling said device with said jaw for transmitting movements of said jaw toward the axis of the work to said device, a, cam, a follower arm for said cam, and means for causing said follower arm when lifted by said cam to lift said caliper aw.

6. In a production gage of the type described, in combination, work-rotating means, work-calipering means including a vertically swingable caliper jaw, a work-checking device, means coupling said device with said jaw for transmitting movements of said jaw toward the axis of the work to said device, a cam, a follower arm for said cam, and adjustable means for causing said follower arm when lifted to a predetermined extent by said cam to lift said caliper jaw.

7. In a production gage of the type described, in combination, work-rotating means, work-calipering means including a vertically swingable caliper jaw, a work-checking device, means coupling said device with said jaw for transmitting movements of said jaw toward the axis of said work to said device, a cam, a follower arm for said cam, said cam having a circumferentially localized dwell timed to pass under said follower arm as a point of given finish radius of the work passes beneath said jaw, and means for causin said follower arm when lifted by said cam to lift said caliper jaw.

8. In a production gage of the type described, in combination, work-rotating means, work-calipering means including a vertically swingable caliper jaw, a work-checking device, means coupling said device with said jaw for transmitting movements of said jaw toward the axis of said work to said device, a cam, a follower arm for said cam, means for causing said follower arm when lifted to lift said caliper jaw, said cam having a cir-cumferentially localized dwell timed to pass under said follower arm as a point of given finish radius of the work passes beneath said jaw, and adjustable means for causing said follower arm when lifted by said cam to a predetermined extent to lift said caliper jaw.

SHUBEL A. FOSTER.

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

UNITED STATES PATENTS Number Name Date 1,834,231 Whitman Dec. 1, 1931 FOREIGN PATENTS Number Country Date 604,377 Germany Oct. 19, 1934

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