US2285847A - Apparatus for making diamond tools - Google Patents

Description

June 9, 1942. R. H. TAYLOR 2,285,847"

APPARATUS FOR MAKING DIAMOND TOOLS Filed Aug. 26, 1941 v 2 Sheets-Shegt l INVENTOR ATTORNE6 I June 9, 1942.

R. H. TAYLOR APPARATUS FOR MAKING DIAMOND TOOLS Filed Aug. 26, 1941 /4 min L :0 i w- I 2 Sheets-Sheet 2 ATTORNEYS Patented June 9, 1942 arraaarus roa MAKING matron!) rooms Rutherford B. Taylor, Millburn, N. 1., .assignor to y when the metal is used in relatively small quan- J. K. Smit 1; Sons, Inc., New York, N. Y., a corporation of New York Application August as, 1941, Serial No. 408,321

4Clalms.

This invention is directed to the casting of diamond tools, particularly core bits, wherein commercial diamonds are embedded or set in a metal matrix and function as the attrition or cutting medium.

One of the objects of my invention is the provision ofequipment whereby I obtain atoolin which the matrix is dense and uniform in it's characteristics, thereby promoting better retention of the diamonds in the matrix and a longer useful'life for the tool.

- To prevent injury to the skin of the diamonds I also provide for casting in an inert atmosphere;

During the-casting operation the mold, which 3 stands vertically, is rotated slowlyon its own This makes for uniform distribution of.

axis. the molten metal which is to constitute the matrix.

Generally speaking, in the making of diamond core bits and diamond tools such as plug bits, dressing tools, etc. the mold is disposed vertically with thecutting stones arranged in the bottom of it and'the molten metal which is to compose the matrix is simply poured into the mold.

While such a method has been used extensively it' has been found diillcult to cast a matrix having uniform characteristics. It will be appreciatedjthat only a relatively. small quantity of metal is used in making the casting and for this reason the metal chills at one part of the mold faster than at others so that, as above noted, there is often an area in the matrix having different characteristics from the remainder of the matrix. T

In the presentinvention the mold, as above stated, is rotated slowly about its vertical axis during the, casting operation which makes for a uniform distribution of the casting metal even tities.

- I have pointed out that in my equipment casting takes place in an inert atmosphere. In this connection, broadly speaking, I provide for exhausting the mold cavity during operation and I for drawing an inert gas through it. In this way 1 I exhaust the mold of any deleterious gases, and

by drawing an inert gas through the mold while themetal of the matrix is being poured I prevent deleterious reaction between the diamonds I and the molten metal during the casting Operation.

In the drawinss wherein I have shown an embodiment of my invention:

partially exploded view of my equip- Fig. 2 is a sectional elevational view; and Fig. 3 is a view on the line 3-3 of Fig. 2.

Referring to the drawings in detail: 2 desig-- nates a suitable bench along which a battery of .5 molds may be arranged when tools are being made in quantities. I have shown but one mold but, as just noted, a battery of molds may be provided in this same bench, all of which would,

of course, be duplicatesof the one illustrated.

Extending through .this bench is a hollow cylindrical member 4 which is provided at its lower end with a removable cap I. The upper end of the member! is capped with a die plate I.

The member 4 constitutes a vacuum or reduced 1 pressure chamber. The die plate 8 is made in sections and the sections are retained in place in a ring gear III by set screws It. The die plate 8 is cup shaped, and. inasmuch as its end or bottom ll constitutes the. mold bottom, this end is shaped to conform to the desired shape of the finished. tool and is provided with perforations It for temporarily receiving the diamonds or cutting stones which are to be embedded in the face of the finished bit.

The ring gear l0 meshes with a pinion ,II on a stub shaft .20 extending through the bench 2- and the peripheral flange 22 formed on the upper end'of the cylinder 4. The lower end of the stub shaft 28 carries a drive pulley which is con'- nected by a belt 26, for instance, to any suitable source of motive power.

The cylindrical member I is provided in one wall with an exhaust line or suction pipe. the

inner end 30 of which is bent downwardly toward the lower end of the cylinder. This line 23 is connected to an exhaust pump 32.

The ring gear 10 and hence the die plate 8 are held down upon the top of the cylinder 4 by yoke members 34 and 36 which are pivoted at 38 and 40 It, respectively, at one side of the ring gear.

The two yoke members are adapted to be swung about, these pivots into and out of superimposed relation to the gear. when the two yoke members are swung into operative position they underlie the head of a stud 42 which sets in the upper face of the flange 22 at the upper end of the cylindrical member 4, so that the gear II and attached die plate are held in position. When the yoke members are opened the. die plate and ring gear can be lifted off as a unit. v

Above the die plate I and resting directly thereon is a mold member 44,- constituting the side ofthe mold, this member along with the die plate providinga moldcavity II. This mold member 44 which is in the form of a ring or 2 annulus is provided at its upper end with a flange 48 extending inwardly radially oi the ring and adapted to cooperate with the outwardly extending flange 50 of the tool shank 52 so that when the nut 54, which is threaded upon the tool shank, is set up the tool shank will be clamped to the flange 48 of the mold annulus 44.

On the bench 2 and offset with respect to the equipment so far described is a post 58 carrying a bracket 54. This bracket can be pivoted on the-post and raised vertically thereof. The bracket 58 carries a gas ring 60 which is undercut, as shown at 62, so that it may be cenmerit of parts within the spirit and scope of my tered with respect to the mold ring 44 when casting.

Carried by the gas ring 80, in fact threaded into this ring, is a valve ring 84, the function of which is to regulate the flow of an inert gas to the mold as well as to provide a pouring lip for the mold.

Inert gas is supplied to the mold from a flask 66 through connection 68, the flow of the gas to the mold being controlled by the valve ring 64, the position of which in the gas ring 60 may be varied by merely rotating the valve ring one way or the other to vary the opening l0 through which the gas must flow in order to reach the mold cavity 46.

In operation the sections of the die plate or mold bottom 8 are assembled and the cutting stones set into the oriflces l6 thereof. The stones are temporarily anchored in positionby the use of a suitable adhesive so that in production a number of die plates may be set up in advance. The die plate together with the attached ring gear I! are placed in position on the top of the cylindrical member 4 and the yoke members 34 and 3t swung into the full line position of Fig. 3. The rest 01' the equipment is then placed in position on top of the die plate, as shown in Fig. 2, and the exhaust pump 32 started in operation. As above pointed out, the inner end 30 of the exhaust line is bent downwardlywith respect to the cylinder 4. This is to prevent metal dropping into the cylinder during casting from dropping into the exhaust line, and I flnd also that I obtain a better and less violent exhausting of the mold cavity than were the exhaust line merely led into the cylindrical member 4 or inclined upwardly. With the pump 82 in operation the gas line 68 is opened so that inert gas such as nitrogen, for example, will be drawn through the mold.

It will be understood, of course, that at this time the mold is being rotated about its vertical axis through the ring gear Ill and pinion It. The molten metal is now poured into the mold through the ring 84 and inasmuch as the mold is being slowly rotated there will be a uniform distribution of the molten metal about the diamonds invention.

What I claim is: g

1. Apparatus for casting diamond tools comprisingin combination a reduced pressure cylinder, means for reducing the pressure in said cylinder, a mold supported on said cylinder and comprising a sectional diamond supporting die plate providing the bottom of the mold and a cap for said cylinder, a ring gear in which said die plate is mounted, and a driving pinion meshing with said ring gear for rotating the mold about the vertical axis of said cylinder.

2. Apparatus for casting diamond tools comprising in combination a reduced pressure vertically mounted cylinder, means including an exhaust line projecting into said cylinder and open-. ing toward the bottom thereof for reducing the pressure in said cylinder, anda mold mounted on the top of said cylinder and comprising e perforated diamond supporting bottom which caps the cylinder. 3. Apparatus for casting diamond tools,-said apparatus comprising in combination a reduced pressure vertically extending'cylinder, an annular flange at the upper end of the cylinder, a

ring gear resting upon and rotatable on said flange, a sectional diamond supporting die plate mounted in and afllxed to said ring gear and constituting a mold bottom as well as a cap for the cylinder, side walls for the mold mounted upon said die plate, and means for driving said ring gear to rotate the mold including said die plate about the vertical axis of said cylinder.

4. Apparatus forv casting diamond tools, said apparatus comprising in combination a reduced pressure vertically mounted cylinder, a diamond supporting die plate immediately above and capping the cylinder, a ring gear in which the die plate is mounted and to which it is afllxed, an'

annular flange on the upper end of the cylinder providing a support for the ring gear and upon which the gear is rotated, and a yoke overlying the ring gear for removably holding the ring gear upon said flange.

RUTHERFORD H. TAYLOR.

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