US2539289A

US2539289A - Grinding block

Info

Publication number: US2539289A
Application number: US42089A
Authority: US
Inventors: Frank A Vavrin
Original assignee: Individual
Current assignee: Individual
Priority date: 1948-08-02
Filing date: 1948-08-02
Publication date: 1951-01-23
Anticipated expiration: 1968-01-23

Description

F. A. VAVRIN GRINDING BLOCK Jan. 23, 1951 Filed Aug. 2, 1948 NNW v A AT TORNEYS l; A further important object of the Patented Jan. 23, 1951 UNITED STATES PATENT OFFICE 2,539,289 GRINDING BLOCK Frank AgVavrin, Racine, Wis. Application August 2, 1948, Serial No. 42,089

1 Claim. 1

This invention appertains to grindin blocks, and more particularly to a novel device for hold-- ing; thread cuttin tools during the sharpening or shapening of the various faces and edges thereof for the correct forming of a certain desired thread on a piece of work.

One of the primary objects of this invention is to provide a simple holding block for the thread cutting tool to be sharpened or shaped, having different angular faces on its sides which correspond exactly to the angle of the faces and edges to be given to the thread cutting tool held by the block, whereby by turning the block in proper sequence on its different faces, the cutter will be held at the exact desired angle relative to the grinding wheel.

Another salient object of the invention is to provide a grinding block for association with a magnetic chuck of a grinding machine, embodying'like angular faces on its opposite "sides corresponding to the angle of the side faces of the thread cutter, an angular face on its rear end corresponding to the desired angle of the leading edge of a cutter, and fiat, horizontal faces n its top and bottom corresponding to the top edge of the tool. I v

invention is the provision of a tumbler rotatably carried by the block in which the cutter is clamped with means for settin and holding the tumbler and Q the tool at the exact desired angle corresponding to the helix angle of the thread to be formed by the tool.

, With these and other objects in view, the invention consists in the novel construction, arrangement and formation of parts, as will be hereinafter more specifically described, claimed and illustrated in the accompanying drawing, in whichdrawing:

Figure 1 is a side elevational view of my novel grinding block with a thread cutter clamped therein and with the block laid on one of its side angular faces for the grinding of one side face of the tool. V

Figure 2 is a central, longitudinal, sectional view through the block showing the block laid on its bottom flat horizontal face.

Figure 3 is a front elevational view of the block with the tool therein and shown in section, the section bein taken on the line 3-3 of Figure 2, looking in the direction of the arrows.

Figure 4 is a transverse sectional view through the block and tool, the section being taken on the line 4-4 of Figure 2, looking in the direction of the arrows, illustrating the means for clamping the tool in the tumbler.

2 Figure 5 is a transverse sectional view through the block and tool taken on the line 5-5 of Figure 2, looking in the direction of the arrows,

illustrating the means employed for clamping the tumbler to the block.

Figure 6 is a transverse, sectional view through the block, taken on the line 6-6 of Figure 2, lookin in the direction of the arrows.

Referring to the drawing in detail, wherein similar reference characters designate corresponding parts throughout the several views, the letter B generally indicating my novel grinding block for a thread cutting tool T.

The thread cutting tool T is of the type commonly employed for cutting threads in a piece of stock, and hence includes the usual bit It! and cutting head I I. The cutting head H, includes the usual side angular faces l2 leading toward the angular front edge [3.

The grinding block B is formed from a single solid piece of metal havin the properties of being attracted to and held by magnetic chuck C. The grinding block B has formed axially therein a cylindrical bore [4, which opens out through the front end of the block. The front face of the block can be provided with an annular rabbet l5 around the bore [4.

Rotatably mounted within the bore 14 is a tumbler IS. The forward end of the tumbler is provided with an annular flange H, which is snugly received within the rabbet l5. The tumbler l6 and its flange l1 fit accurately within the block, but is free for turning movement therein. The axial center of the tumbler is provided with a socket H! which snugly receives the bit ll] of the tool. Obviously, the cros sectional configuration of the socket I8 corresponds to the cross sectional configuration of the bit. Extending into the tumbler I6 is a set screw l9 and this set screw is employed for tightly clamping the bit of the tool in the tumbler. To permit turning of the tumbler in the block, the upper face of the block is provided with a transverse slot 20 and the set screw l9 moves in this slot during the turning of the tumbler.

The tumbler is also clamped tight in the block after the setting thereof, as will be later pointed out, and this clamp includes a friction shoe 2| received in a semi-circular groove 22 formed in the tumbler I6. Bearing against the shoe is a set screw 23, which is threaded in the block. Obviously, by threading down on the set screw, the shoe can be brought into firm clamping engagement with the tumbler.

The front face of the block has formed thereon or associated therewith, a scale 24, and this scale is graduated for left hand and right hand threads. The tumbler is provided with an indicating arrow or line 25, for cooperation with the graduations.

The formation of the outer surface of the block is important and these faces correspond to the angularit of the faces of the tool to be sharpened and shaped. The bottom and top faces 26 and 2'! of the block are fiat and parallel to one another, and parallel to the gripping faces of the magnetic chuck C.

The side faces 28 and 29, adjacent to the rear end of the block angle rearwardly to the longitudinal axis of the block. The exact angle of these faces is carefully computed to correspond to the side face [2 of the cutting tool exactly. The rear face of the block 30 is angularly disposed relative to the transverse axis of the block. The angle of the face 30 is carefully formed and corresponds exactly to the angle of the front edge l3, Of the tool.

In the use of my block the tool bit it] is placed Within the socket l8 and is firmly clamped therein by the set screw l9, as is commonly shown in Figure 2. The helix angle is computed and the tumbler IS with the tool inside is turned to the corresponding angle on the scale 24 for right or left hand threads, as the case may be. The set screw 23 is now tightened to lock the tumbler in its set position. The tool T is then ready for grinding. The block B is then laid on the face 28, as shown in Figure 1, on the chuck C, in the correct position relative to the grinding wheel (not shown), and the tool is ground on one side;

After this side is ground, the block is turned and tool gage. If necessary, for some tools, the block is laid on its face 21 and the upperedge of the tool is ground.

From the foregoing description, it can be seen that I have provided an exceptionally simple block in which, after the tool is once set in the block in the desired angle, the faces thereof can be accurately ground by the mere turning of the block on its different angular sides.

Obviously diiferent blocks can be provided for different characters of threads.

Various changes in details may be made without departing from the spirit or the scope of my invention, but what I claim as new is:

In a grinding block for threaded cutting tools adapted to be associated with a magnetic chuck, a solid body having different angular faces on its outer sides corresponding exactly to the angu lar faces and edges of the tool to be sharpened and a fiat front face, said block having an axial bore opening out through the front face and a transversely extending slot communicating with the bore opening out through a side of the block, the front face of the block having an annular rabbet surrounding the bore, a tumbler mounted in said bore for receiving a tool, an annular flange on the forward end of the tumbler received in said rabbet and said flange having its 'outer face flush with the front face, a set screw received in the slot threaded in the tumbler for clamping engagement with the tool in the bore, said setscrew being movable in the slot for turning the tumbler, means carried by the block adjacent to the slot for clamping the tumbler and tool in a desired set'position in the block, said block and tumbler having a cooperating scale and indicator.

FRANK A. VAVRIN.

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

UNITED STATES PATENTS Number Name Date 727,355 Han-sen Ma 5, 1903 1,908,155 Jorgensen May 9, 1933 2,385,902 Wilson Oct 2; 1945