Means To Assure Uniform Flow Of An Abrasive Solution

Abstract

A means of supplying an abrasive solution to a lapping machine having a rotating lapping plate, and which solution comprises a liquid having an abrasive in suspension. The solution is supplied under pressure to a tubular member having a rod freely rotatable therein, permitting the solution to flow axially along the rod and to be deposited upon the lapping plate. A plurality of arms extend normal to the axis of the rod and integral therewith are periodically engaged to rotate the rod and assure breaking up of any concentration of particles in the solution that would interfere with the uniform flow of the solution.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention concerns devices employed to supply abrasive solutions to lapping machines during the process of lapping.

2. Description of the Prior Art

The prior art includes a means of supplying an abrasive solution in which the flow is periodically interrupted to assure dislodgement of grit that would tend to clog the orifices and affect the uniform flow of the lapping solution.

SUMMARY OF THE INVENTION

This invention concerns a means of providing constant and uniform flow of an abrasive solution to a lapping plate which solution comprises a fluid having abrasive particles suspended therein. The solution is supplied under pressure to a rotating rod member confined freely within a bore; the solution flowing axially along the rod, and then deposited upon the lapping plate. The rotating rod member is provided with radial arms extending normally thereto. A rotatable work-confining ring member rests upon the plate for free rotation thereon and has an indexing pin extending upwardly so as to periodically engage one of the arms to rotate the rod member. An object of this invention is to dislodge concentrated particles of the abrasive to permit uniform flow of the solution axially of the rod.

Referring to the drawings:

FIG. 1 is a fragmentary plan view of a portion of a lapping machine embracing the invention.

FIG. 2 is an elevational view of the machine of FIG. 1.

FIG. 3 is an enlarged plan view of a portion of FIG. 1.

FIG. 4 is an elevational view of FIG. 3 with parts broken away.

FIG. 5 is an axial view of a portion of FIG. 4 taken at 5--5 of FIG. 4.

FIG. 6 is an enlargement showing a modification of FIG. 3.

FIG. 7 is an elevational view of FIG. 6.

FIG. 8 is an enlarged view of a portion of FIG. 7 with parts broken away.

FIG. 9 is a section taken at 9--9 of FIG. 7.

A typical lapping machine embracing this invention is shown in FIGS. 1 and 2, in which the lapping machine comprises a frame 10 on which a lapping plate 12 rotates about an axis 14, in the direction of arrow 16, and having a lapping surface 18.

A conditioning ring 20 rests freely upon the surface 18 of lapping plate 12. A cradle 22 partially embraces ring 20 and limits the rotation thereof about its axis 24 by means of rollers 26 and 28, and in the direction indicated by the arrow 30.

Cradle 22 is supported on frame 10 by a post 32 and a nut 34. Ring 20 has a concentric opening 36. Work pieces to be lapped (not shown) are freely confined within the opening 36 and rest freely upon the surface 18 of plate 12.

The angular position of rollers 26 and 28 with respect to line 38 in such that ring 20 will rotate about axis 24 in the direction of arrow 30 at a rate proportional to the rotation of plate 12 about the axis 14, and considerably less.

The abrasive supply means 40 comprises an upright tubular portion 42 having an axis normal to the surface of plate 12. Tubular portion 42 terminates upwardly in a tubular support member 44 which is of the shape shown. Portion 44 extends downwardly for connection with a pump and reservoir 46 which supplies the abrasive solution under pressure. Portion 44 comprises a loop having terminal portions 45 and 48; the solution flowing from reservoir 46 in the direction of arrow 50 and returning to the reservoir in the direction of arrow 52; thus supplying a continuous flow of the solution to the lapping operation.

Tubular portion 42 is integrally fixed in supply member 44 in an opening, and has an axial bore 54 in fluid connection with member 44. A rod member 56 extends axially through bore 54 and is of a diameter substantially smaller than that of bore 54, to permit flow of the abrasive solution axially along the rod.

A plurality of arms 58, 60 and 62, in this instance, extend radially and are positioned in a plane below the end of portion 42. It is desirable to provide a dampening means to prevent excessive free rotation of the rod member 56 in the bore 54. A disk 64 is fixed integrally about portion 42. A dampening finger 66 is secured integrally to rod 56 and is of the shape shown. Finger 66 frictionally engages to upper surface of disk 64 with a pressure sufficient to maintain contact between the upper end of rod member 56 and the inner surface of supply member 44, thus providing means to dampen free rotation of the rod member 56.

Conditioning ring 20 has provided in the rim thereof an upright index pin 68. The purpose of pin 68 is to periodically engage one of the arms 58, 60 and 62 in turn as the ring 20 rotates in the direction of the arrow 30, thus rotating rod 56 in the direction of the arrow 70. Pin 68 is also shown by dotted lines in the position that it would appear when indexing the arm 62 to rotate the rod 56.

FIGS. 6 through 9 concern a modification of the showing of FIGS. 3 and 4. Tubular portion 72 has a bore 74 surrounding the rod 76. Other details similar to those indicated in regard to FIGS. 3 through 5 are similar and need not be further described. The modifications concern the adjustment of the flow of the abrasive solution axially along rod 76, which can be of various diameters to permit control of the quantity of the abrasive solution being supplied to the lapping plate 12.

An auxiliary means to control the flow of the solution is shown in FIGS. 7 and 8. The end of portion 72 has a plane normal to the axis thereof as at 78. Portion 72 has a thread 80 extending upwardly from the end. A sleeve 82 is internally threaded to permit the sleeve to be adjusted axially relative to the portion 72. The thread in sleeve 82 terminates downwardly in an axial, upwardly-diverging cone-shaped seat 84. A resilient "O" ring 86 freely surrounds rod 76 and rests in seat 84. The purpose of ring 86 is to provide a means of controlling the quantity of abrasive solution flowing along rod 76. If it is desired to reduce the flow of the solution, sleeve 82 is threaded upwardly to compress the "O" ring 86 radially, thus causing a reduction in the passage of the solution along the rod 76. It is also the intention to vary the diameter of the rod 76 to accomplish a reduction or an increase in the flow of the solution along the rod 76, as an alternative.

The path of the abrasive solution follows the periphery of the rod 76, or 56 to be deposited on the lapping plate surface 18. In the event that an accumulation of abrasive particles tend to clog or otherwise obstruct the flow of the solution, the periodic rotation of the rods 56 or 76 will tend to disolve the obstruction and permit consistent flow of the solution.

Claims

The above being a complete description of an illustrative embodiment of the invention, what is claimed as new and desired to be secured by Letters Patent of the United States is:

1. In a lapping machine having a lap plate rotatable about a first axis, and a work-confining ring member having an opening, and in contact with, and freely rotatable on said plate about a second axis radially positioned relative to said first axis, in combination, a means to apply an abrasive solution to the surface of said plate, comprising an upright tubular dispensing member having an axial bore and terminating upwardly in a solution-supply member, said bore having fluid connection with said supply member, a rod freely rotatable in said bore and being of a diameter substantially less than the diameter of said bore and extending below said dispensing member, a plurality of radially-extending circumferentially-spaced arms integral with said rod and lying in a plane below said dispensing member, normal thereto and above said ring, a means to index rotation of said rod comprising an upright index member integral with said ring, and successively engageable with each of said arms to rotate said rod upon rotation of said ring.

2. In a lapping machine as set forth in claim 1, in which means is provided to dampen the free rotation of said rod in said bore.

3. In a lapping machine as set forth in claim 1, in which said upright tubular dispensing member terminates downwardly in a seat normal to the axis of said member and surrounding said rod, a resilient ring member freely surrounding said rod and in engagement with said seat, a sleeve surrounding said upright dispensing member and having an upwardly-diverging conical seat in engagement with said resilient member, and means to adjust said sleeve axially relative to said tubular dispensing member to radially contract said resilient member to control the passage of said solution axially in said bore.