US3122866A

US3122866A - Workpiece locator

Info

Publication number: US3122866A
Application number: US210627A
Authority: US
Inventors: Maurice J Gross
Original assignee: Barnes Drill Co
Current assignee: Barnes Drill Co
Priority date: 1962-07-18
Filing date: 1962-07-18
Publication date: 1964-03-03
Anticipated expiration: 1981-03-03
Also published as: DE1879851U; GB966844A

Description

M. J. GROSS WORKPIECE LOCATOR March 3, 1964 4 Sheets+$heet 1 Filed July 18, 1962 rovzmrrow l 0% cflwomos f March 3, 1964 J, GROSS 3,122,866

WORKPIECE LOCATOR Filed July 18, 1962 4 Sheets-Sheet 2 Wm Q'YLQOV Lena Gwamxr March 3, 1964 M. J. GROSS 3,122,866

WORKPIECE LOCATOR Filed July 18, 1962 4 Sh eets-Sheet 3 Jae QYIcuJwLqe GIOJJ 4 41. 4; W a: u

(fl TTORI'OEYL/ March 3, 1964 M. J. GROSS 3,122,866

WORKPIECE LOCATOR Filed July 18, 1962 4 Sheets-Sheet 4 971a an ce QmsJ 22 6 4);? (0M @w-r r-uQEZYJ" United States Patent Ofifi ce 3,122,865 Patented Mar. 3, 1964 3,122,866 WQRKPEECE LGKIATGR Maurice 3. Gross, Rockford, EL, assignor to harnes Drill (10., Rockford, iii, a corporation of lllinois Filed July 18, 19-62, Ser. No. 210,627 3 61mins. (Cl. 51--227) This invention relates to a fixture for holding workpieces while the latter are being machined and, more particularly, to a fixture adapted to hold a plurality of workpieces each having a bore to be operated upon as by a hone. The workpieces are clamped to the fixture with their bores alined and, prior to clamping, the bores are alined by a locator which is projected through the bores.

The general object of the invention is to provide a new and improved locator which precisely positions all of the workpieces simultaneously and which is effective to do this even though the bores may vary slightly in diameter.

A more detailed object is to form the locator with a plurality of independently expandible parts, one for each workpiece, and to expand these parts in the bores so that the bores are centered about the expandible parts.

The invention also resides in the novel construction of the expandible parts and in the means for expanding them simultaneously but individually.

Other objects and advantages of the invention will become apparent from the following detailed description taken in connection with the accompanying drawings, in which FIGURE 1 is a perspective view of a honing machine in which the workpieces are held by a fixture incorporating a novel locator of the present invention.

FIG. 2 is an enlarged perspective view of a workpiece.

FIG. 3 is an enlarged fragmentary sectional view taken along the line 3-3 in FIG. 1.

FIG. 4 is an enlarged fragmentary sectional view taken along the line 44 in FIG. 3.

FIG. 5 is a view similar to FIG. 4 but on a reduced scale and showing the parts in a different position.

FIG. 6 is an enlarged view similar to FIG. 4 and showing the parts in still another position.

FIG. 7 is an enlarged fragmentary sectional view taken along the line 7-7 in FIG. 4.

FlG. 8 is an enlarged fragmentary sectional view taken along line 88 in FIG. 3.

FIG. 9 is a bottom view of a sleeve which forms a part of the locator.

FIG. 10 is a perspective view of the sleeve.

As shown in the drawings for purposes of illustration, the invention is embodied in a fixture lil adapted to hold a workpiece such as a connecting rod 3.1 while the bore 12 of the latter is being honed. The fixture may be mounted on the base 13 of a suitable honing machine 14 with the bore of the connecting rod coaxial with the spindle 15 of the machine. As is usual in such machines, the spindle is driven by a motor in a head 16 which slides up and down on vertical guides 17 supported by a column 18 upstanding from the base 13. The head is reciprocated on the guides while the spindle is rotated so that the bore of the connecting rod is honed by the tool (not shown) supported on the lower end of the spindle.

The fixture it is adapted to support a plurality of workpieces 11 one above the other with the bores 12 in vertical alinement and, for this purpose, the fixture comprises a body 19 (FIG. 4) rotatable on a stationary base 29 about a vertical axis a which is laterally offset from the axis [2 of the spindle 15'. The body supports two stacks of clamps Z1 and 21' diametrically disposed on opposite sides of the axis a and, in the position illustrated in FIG. 4, the clamps 21 are in the inactive or loading position While the clamps 21' are in the active position along the spindle EIXiS. Each of the clamps 21 is composed of spaced

jaws

22 and 23 which present opposed clamping surfaces for gripping opposite sides of the workpiece and the jaws 22 are rigid with the body w while the jaws 23 are movable, each independently of the other, toward and away from the corresponding fixed jaws. The clamps 21 are identical in construction and the corresponding parts are identified by the same but primed reference characters.

In the present instance, the fixed jaws 22 are the lower jaws of the clamps 21 and, except for the lowermost one, are formed by vertically spaced blocks, the fixed jaw of the bottom clamp being part of a horizontal plate 22 as shown in FIG. 4. The blocks are held apart by spacers 24 and the blocks, the spacers, and the plate 22 are bolted together to form a rigid, unitary assembly which constitutes a major portion of the body 19. The blocks 22 and the plate 22 are formed with

alined holes

25 and 25 slightly larger than the bores 12 of the connecting rods 11 but small enough so that the outer circumferential portion of the bosses 26 surrounding the bores rest on the fixed jaws 22. Thus, the blocks 22 and the spacers 24 form recesses or slots which loosely receive the connecting rods.

The movable jaws 2-3 are rings slidably received in annular grooves 27 (FIG. 8) formed in the undersides of the blocks 22 and function as pistons. Thus, fluid pressure is admitted to the grooves 27 behind the rings 23 which thereby are moved toward the opposing fixed jaw 22 and into clamping engagement with the connecting rod. Fluid pressure for closing the clamps is supplied through a passage 28 (FIG. 4) in a stationary trunnion 29, the passage being connected to a manifold passage 30 in the body 19 and branch passages 31 being provided to connect the manifold passage with the individual grooves 27. A similar supply passage 25 is connected to the grooves 27' of the clamps 21 through a manfold passage 30' and branch passages 31. The

supply passages

23 and 28 are connected to a suitable source of fluid pressure by

individual lines

32 and 32 which are separately controlled by a valve mechanism (not shown) so that each set of clamps may be opened and closed independently of the other.

With the foregoing arrangement, one set of clamps, the clamps 21' in FIG. 4, is in the active position and the workpieces held thereby may be honed while the other set of clamps 21 is being loaded. When the machining of the first set of workpieces has been completed, the body 19 is turned through degrees so that the original set of workpieces may be removed and the second set of workpieces honed. To support the body for turning about the axis a, a bearing plate 33 is secured to the underside of the plate 22 and rides on the base 2%. A shaft 34 coaxial with the axis a depends from the underside of the bearing and turns in a bearing sleeve 35 received in the base 29. The upper end of the body is supported for turning by the trunnion 29 which projects into a central bore 36 in the body 19 and is carried by a horizontal bracket 37 which is secured to and projects laterally from the column 18 of the machine 14. The body is turned by a hydraulic actuator 33 of the piston and cylinder type with the piston rod 39 of the actuator having a rack formed along its length to engage a pinion 4t keyed to the lower end of the shaft 34. Turning of the body 19 in each direction is limited by lugs 41 (FIG. 3) which are carried by the plate 22* and which engage stops 42 on the base 2%.

Before the clamps 21 are closed, the workpieces 11 are positioned so that the bores 12. are in alinement and, for this purpose, an elongated locator 43, which normally is disposed beneath the plate 22 is projected up through the hole 25 in the plate and through the bores. The present invention contemplates the provision of a novel locator which simultaneously positions all of the workpieces with each bore 12 precisely centered on the axis of the locator even though the various bores differ slightly in diameter. For this purpose, the locator includes separately expandible portions 44 for each bore and these portions are expanded within the bores while the locator is disposed along the axis 0 thereby centering the bores about the expandible portions and hence about this axis.

In the present instance, the expand-ible portions 44 are slotted skirts on individual sleeves 45 (FIGS. 8, 9 and 10) which are disposed end to end and are slidably received on a tube 46. The latter is coaxial with the axis 0 and normally is disposed in an inactive position beneath the plate 22 as shown in FIG. but is projected up through the bores 12 before the workpieces are clamped (see FIG. 4). Such movement is achieved herein by fluid pressure and, for this purpose, the upper end of the tube is closed .by a cylindrical cap 47 threaded into the tube and the latter slides on a stationary piston 48 fixed to the upper end of a hollow rod 49. The lower end of the rod projects into a block 50 on the base 26 where its interior is connected to a fluid pressure line 51 by a passage 52 in the block and the upper end opens into the tube 46 below the piston whereby pressure fluid from the line 51 lowers the tube. To raise the tube, pressure fluid from a second line 53 is admitted above the piston through a passage 54 and a pipe 55 which is disposed within the rod 49 and projects through the piston.

In the upper or active position of the locator 43, the latter is centered accurately on the axis 0 which becomes the axis b when the body 19 is turned through 180 degrees, by

cylindrical bushings

56 and 57 in the base 20 and the bracket 3-7 respectively. The bushing 56 receives the enlarged lower end portion 58 of the tube 46 while the cap 47 projects into the bushing 57, the upper edge of the cap being chamfered as indicated at 59 to guide the cap into the bushing 57. At its lower end, the tube 46 carries an'arrn 69 which actuates the lever 61 of a suitable interlock device '62 in the control of the hydraulic actuator 38 to prevent turning of the body 19 when the locator is up.

Herein, the skirts 44 of the sleeves 45 are expanded by a c'amming action after they are positioned in their respective bores 12 and, for this purpose, the lower edges of each skirt are formed internally with an annular inclined cam surface 63 (FIG. 8) which engages a complemental cam surface 64 formed on the upper end of the adjacent sleeve, the cam surface on the lower terminal sleeve coacting with an annular cam surface 64 on the exterior of the tube 46. By moving the mating cam surfaces relative to each other so that cam surface 64 moves further into the adjacent sleeve, the skirt 44 is expanded to bringa' rib 65 on the exterior of the skirt against the wall of the bore 12 and center the bore on the axis 0.

In the form of the invention illustrated in the drawings, pressure fluid is used to move the cam surfaces 63 and 64 relative to each other and this is achieved by stopping the upper terminal sleeve 45 after all the skirts 44 have entered their respective bores 12 and utilizing the final upward movement of the tube 46 to advance each cam surface 64- up along the coacting cam surface 63. For this purpose, the upper terminal sleeve is formed with an annular surface 6-6 which is beveled like the cam surfaces 64 to facilitate the passage of the locator 43 through the bores 12 and which abuts against a mating surface 67 on the lower end of the bushing 57 to stop the upper sleeve, the parts then being in the position shown in FIG. 6. The fluid pressure in the tube, however, continues to raise the latter and the cam 64 and shifts the remaining sleeves further up to expand the skirts. Such expansion continues until the cap 47 engages a stop 68 which preferably is a screw threaded through a plate 70 on the bracket 37 so that the amount of movement of the tube and hence the degree of expansion of the skirts 44 can be adjusted according to the size of the bores 12. Helical compression springs 71 disposed within the skirts 44 act between internal shoulders 72 on the sleeves and the ends of the adjacent sleeves to return'the sleeves to their original positions, as limited by the upper end of the upper terminal sleeve engaging the underside of the cap 47, when the locator is retracted.

It will be observed that a locator 43 constructed according to the invention accurately centers each bore 12 about the axis 0. The pressure fluid in the tube 46 expands all of the ribs 65 against the walls of the respective bores with equal force regardless of slight variations in the sizes of the bores so that all the bores are centered precisely. Asa result, only a minimum amount of metal need be removed from the workpieces by the honing operation.

I claim:

1. In a fixture for holding a plurality of workpieces each having a bore, a locator for positioning the work pieces with the bores in precise axial alinement, said locator comprising an elongated tube substantially smaller in diameter than the bores of said workpieces and adapted to be projected axially through the bores, a first annular cam surface formed on said tube adjacent the one end thereof, a plurality of sleeves including first and second terminal sleeves slidably received on said tube in longi .tudinal succession with the first terminal sleeve adjacent of each successive sleeve engaging the other end of the adjacent sleeve, second cam surfaces formed on said other ends whereby movement of each cam surface relatively toward the adjacent skirt expands the skirt radially, a stop engageable with said second terminal sleeve and operable to hold the latter against axial movement when said skirts are in said bores, means for admitting pressure fluid to the interior of said tube to move the latter axially and advance said first cam surface toward said second terminal sleeve thereby simultaneously to expand all of said skirts, and a plurality of springs, one acting on each of said sleeves to move the sleeves away from the corresponding cam surfaces upon release of said pressure fluid to permit the skirts to contract.

2. In a fixture for holding a plurality of workpieces each having a bore, a locator for positioning the workpieces with the bores in precise axial alinement, said locator comprising an elongated tube substantially smaller in diameter than the bores of said workpieces and adapted to be projected axially through the bores, a first annular cam surface formed on said tube adjacent the one end thereof, a plurality of sleeves including first and second terminal sleeves slidably received on said tube in longitudinal succession with the first terminal sleeve adjacent said surface and the second terminal sleeve adjacent the other end of said sleeve, each of said sleeves having an expandible skirt at one end with the skirt .of said first terminal sleeve engaging said cam surface and the skirts of each successive sleeve engaging the other end of the adjacent sleeve, second cam surfaces formed on said other ends whereby movement of each cam surface relatively toward the adjacent skirt expands the skirt radially, a stop engageable with said second terminal sleeve and operable to hold the latter against axial movement when said skirts are in said bores, means for admitting pressure fluid to the interior of said tube to move the latter axially and advance said first cam surface toward said second terminal sleeve thereby simultaneously to expand all of said skirts, and a second stop engaging said tube after a predetermined amount of movement to limit the expansion of said skirts.

3. In a fixture for holding a plurality of workpieces each having a bore, a locator for positioning the workpieces with the bores in precise axial alinement, said locator comprising an elongated tube substantially smaller in diameter than the bores of said workpieces and adapted to be projected axially through the bores, a first annular cam surface formed on said tube adjacent the one end thereof, a plurality of sleeves including first and second terminal sleeves slidably received on said tube in longitudinal succession with the first terminal sleeve adjacent said surface and the second terminal sleeve adjacent the other end of said sleeve, each of said sleeves having an expandible skirt at one end with the skirt of said first terminal sleeve engaging said cam surface and the skirts of each successive sleeve engaging the other end of the adjacent sleeve, second cam surfaces formed on said other ends whereby movement of each cam surface relatively toward the adjacent skirt expands the skirt radially, a stop engageable with said second terminal sleeve and operable to hold the latter against axial movement when said skirts are in said bores, and means for admitting pressure fluid to the interior of said tube to move the latter axially and advance said first cam surface toward said second terminal sleeve thereby simultaneously to expand all of said skirts.

4. In a fixture for holding a plurality of workpieces each having a bore, a locator for positioning the workpieces with the bores in precise axial alinement, said locator comprising an elongated tube substantially smaller in diameter than the bores of said workpieces and adapted to be projected axially through the bores, a first annular cam surface formed on said tube adjacent the one end thereof, a plurality of sleeves including first and second terminal sleeves slidably received on said tube in longitudinal succession with the first terminal sleeve adjacent said surface and the second terminal sleeve adjacent the other end of said sleeve, each of said sleeves having an expandible skirt at one end with the skirt of said first terminal sleeve engaging said cam surface and the skirts of each successive sleeve engag'ng the other end of the adjacent sleeve, second cam surfaces formed on said other ends whereby movement of each cam surface relatively toward the adjacent skirt expands the skirt radially, a stop engageable with said second terminal sleeve and operable to hold the latter against axial movement when said skirts are in said bores, and means operable to move said tube axially in a direction to advance said first cam surface toward said second terminal sleeve thereby simultaneously to expand all of said skirts.

5. In a fixture for holding a plurality of workpieces each having a bore, a locator for positioning the workpieces with the bores in precise axial alinement, said locator comprising an elongated tube substantially smaller in diameter than the bores of said workpieces and adapted to be projected through the bores, an annular cam surface formed on said tube adjacent one end thereof, a plurality of sleeves including first and second terminal sleeves slidably received on said tube in longitudinal succession, each of said sleeves having an expandible skirt at one end with the skirt of said first terminal sleeve engaging said cam surface and the skirts of successive sleeves engaging the other end of the adjacent sleeve, cam surfaces formed on said other ends whereby movement of each cam surface relative to the adjacent skirt expands the skirt radially, and fluid pressure means acting on said terminal sleeves and operable to move the terminal sleeves relatively toward each other thereby simultaneously to expand all of said skirts.

6. In a fixture for holding a plurality of workpieces each having a bore with the bores in alinement and axially spaced apart by a predetermined distance, a locator for positioning the workpieces in precise axial alinement, said locator comprising an elongated member adapted to project simultaneously through the bores of all of the workpieces, annular parts carried by said member and axially spaced along the member by said predetermined distance whereby one part is disposed Within each bore, said parts being radially expandible against the wall of the associated bore, said member being hollow, and means for admitting pressure fluid to the interior of said member thereby to expand said parts and center said bores about said member.

7. In a fixture for holding a plurality of workpieces each having a bore, a locator for positioning the workpieces With the bores in precise axial alinement, said 10- cator comprising an elongated tube substantially smaller in diameter than the bores of said workpieces and adapted to be projected through the bores, an annular cam surface formed on said tube adjacent one end thereof, a plurality of sleeves including first and second terminal sleeves slidably received on said tube in longitudinal succession, each of said sleeves having an expandible skirt at one end with the skirt of said first terminal sleeve engaging said cam surface and the skirts of successive sleeves engaging the other end of the adjacent sleeve, cam surfaces formed on said other ends whereby movement of each cam surface relative to the adjacent skirt expands the skirt radially, and means operable to move said terminal sleeves relatively toward each other thereby simultaneously to expand all of said skirts.

8. In a fixture for holding a plurality of workpieces each having a bore with the bores in alinernent and axially spaced apart by a predetermined distance, a locator for positioning the workpieces in precise axial alinement, said locator comprising an elongated member adapted to project simultaneously through the bores of all of the workpieces, a series of annular parts carried by said member and axially spaced along the member by said predetermined distance whereby one part is disposed within each bore, said parts being radially expandible against the wall of the associated bore, and means operable to expand said parts and center said bores about said member in succession beginning with a terminal part and expanding each successive part automatically as an incident to expansion of the preceding part.

References Cited in the file of this patent UNITED STATES PATENTS 11,810,214 Johnson June 16, 1931 1,873,819 Butterworth Aug. 23, 1932 1,90 5,102 Johnson Apr. 25, 1933 2,229,477 Shannon Jan. 21, 1941 2,520,249 La Pointe Aug. 29, 1950 2,615,413 Adams et a1 Oct. 28, 1952 2,829,470 Johnson Apr. 8, 1958 2,844,053 Wagner et al July 22, 1958 2,846,379 Chambers et al Aug. 5, 1958 6,087,281 Greening et al Apr. 30, 1963

Claims

8. IN A FIXTURE FOR HOLDING A PLURALITY OF WORKPIECES EACH HAVING A BORE WITH THE BORES IN ALINEMENT AND AXIALLY SPACED APART BY A PREDETERMINED DISTANCE, A LOCATOR FOR POSITIONING THE WORKPIECES IN PRECISE AXIAL ALINEMENT, SAID LOCATOR COMPRISING AN ELONGATED MEMBER ADAPTED TO PROJECT SIMULTANEOUSLY THROUGH THE BORES OF ALL OF THE WORKPIECES, A SERIES OF ANNULAR PARTS CARRIED BY SAID MEMBER AND AXIALLY SPACED ALONG THE MEMBER BY SAID PERDETERMINED DISTANCE WHEREBY ONE PART IS DISPOSED WITHIN EACH BORE, SAID PARTS BEING RADIALLY EXPANDIBLE AGAINST THE WALL OF THE ASSOCIATED BORE, AND MEANS OPERABLE TO EXPAND SAID PARTS AND CENTER SAID BORES ABOUT SAID MEMBER IN SUCCESSION BEGINNING WITH A TERMINAL PART AND EXPANDING EACH SUCCESSIVE PART AUTOMATICALLY AS AN INCIDENT TO EXPANSION OF THE PRECEDING PART.