US1080980A - Tap. - Google Patents

Description

T. F. KHAN.

TAP.

APPLICATION FILED MAILQ, 1912.

' 1,080,980, Patented Dec.9, 1913.

2 SHEETS-SHEET 1; 5

l r 4 x I v fiaa/r 0/41 wf/Yiif may I. Q

' 8 1% M if coLu/num PLANuunm-il cu. WASHINGTON. u. c.

T. F. KEAN.

TAP.

APPLICATION FILED MAR. 9, 1912.

Patented Dec. 9, 1913.

2 SHEETSSHEET 2.

CDLUMBIA PLANCIGRAPH co, WASHINU'IION,

UNITED PTT @FFTC.

THOMAS F. KEAN, or BOSTON, MAs'sAonusnTTs, ASSIGNQROF oivn rinnr To ILLTAM A. MACLEOD AND ELDON MACLEOD, or WESTWOQD, u ssAoHUsnTT's, AND CHARLES w. MGGONNEL, or BOSTON, MAssAorfUsnTTs, TRUSTEES.

TAP.

Specification of LettersPatent.

Patented'Dec. 9, 1913.

Application filed narch'ejieia serial naesajros.

To all whom'z'zf ma concern.-

Be it known that I, THOMAS F. KEAN, a citizen of the United States, residing at Boston, county of Suflolk, State of Massachusetts, have invented a certain new and useful Improvement in Taps, of which the following is a specification, reference being had therein to the accompanying drawings.

My invention has for its object an improvement in automatic taps of the type in which the cutters are automatically withdrawn from engagement with the threads when a predetermined point has been reached so that the work may thereafter be drawn back from the tap without rotating either tap or work.

deretofore, so far as is known to me, it has been customary to construct devices of this character in such a manner that the automatic latch by means of which the cutters are disengaged from the threads is operated when the face of the nut or other piece of work which is next to the tap contacts with the trigger of the latch.

The device embodying my present invention is so constructed that the trigger contacts with the bottom of the hole to be tapped instead of the face of the nut or other article and therefore the tap may be stopped with great accuracy at any predetermined distance from the bottom of the hole, thereby making it possible to tap thin or irregular pieces of work.

The tap embodying my present invention is also constructed so as to be very efficient and durable and the cutters are readily movable but without lost motion, while at the same time they are supported in a solid block of metal so that the device has the rigidity of a solid tap. A convenient means of adjustment for depth of hole is also provided as well as means whereby the position of the cutters may be changed as required to compensate for wear.

The invention will be fully understood from the following description taken in connection with the accompanying drawings, and the novel features thereof will be pointed out and clearly defined in the claims at the close of the specification.

In the drawings, Figure l is a top plan View of a device embodying my present invention some portions being broken away to; illustrate the device more clearly. Fig. 2 1s asideelevat'ion of a tap embodying my invention, some of the parts being also broken away. Fig. 3 is a section on line 3'-8 of Fig. 1 looking in the direction of the arrow. Fig. 4.- is a section of the block or body in which the cutters are supported being taken on line 4-i Fig. 2 looking in the direction of the arrows. Fig. 5 is a side view of one cutter. Fig. 6 is a side view of one wedge, being one which operates the cutter shown in Fig. 5. Fig. 7 is a section on line 7-7 Fig. 5. Fig. 8 is a section on line 8-8 Fig. 6.

Referring now to the drawings: At A is shown the arbor which is placed in the turret-head. At B is shown the body or block of the t'ap within which are received the four cutters C. To the arbor A is rigidly fastened a collar D by means of a set-screw 11. The arbor A, the body B, the collar D are all rigidly connected and therefore are stationary relatively to each other. The cutters C are 'sli'dable radially in the body B and are moved by Wedges 15 secured to a head 12 which is slidable on the arbor A, being moved in one direction by means of the rotatable cam 13, and in the other direction by the springs 14.

The slots 16 in the body B containing the wedges 15 and cutters C are T-shaped in cross-section as will be plainly seen from Fig. 4, to receive two longitudinal ribs 17 and 18 on the said wedges. The cutters G are connected with the wedges 15 by means of a rib 19 on the cutter which interlocks with a groove 20 on the wedge, and a rib 21 on the wedge which interlocks with the groove 22 on the cutter. As the two members are confined in the groove 16 in the block B, the cutter C is secured firmly in place in the block B and may be moved in either direction by the wedge 15, this movement being a positive one in both directions owing to the interlocking connection between the cutter and the wedge. This construction is also such that the cutters cannot become displaced or drop out. The cutters C are themselves guided radially by means of two slots 23 and 24 one in eachside of each cutter, these slots being engaged by the edges of an adjacent pair of segmental plates 25 secured to the block B by the screws 26. As the wedges 15 and the cutters C are both wedge shaped as shown in Figs. 5 and 6, it will be seen that a longitudinal movement of the wedges, 6. parallel with the axis of the arbor will move the cutters radially but the cutters will not be moved longitudinally. The four wedges 15 are rigidly secured to the head 12 by means of four screws 27, there being interposed between the wedge and the head 12 a sleeve or thimble 28. K

The cam 13 is cut with two cam faces 29 and 30 and is secured to the collar although rotatable relatively to it, by two semi-circular plates 31, 32, which are screwed to the cam 13. The cam is provided with a handle 321 by means of which it is rotated. Two wedge-shaped fixed cam followers 33 and 34 are secured to the head 12 and are held in contact with the cam faces 29 and 30 by the springs 14, one end of each of which bears against the lower face of the head 12 while the other end rests on the body B. "When the cam 13 is rotated about sixty degrees by means of the handle 321, the head 12 and the wedges 15 secured thereto are moved to the left as shown in Fig. 1, thereby moving the cutters G into operative position. The parts are secured in this position by means of a latch stud 341 secured to the block 13. The latch stud 341 is provided with an annular groove 35 which is engaged by a latch 36 which is slidable in a hole in the head 12. The latch 36 is pressed against the latch stud 341 by the spring 37, the tension of which is adjusted by the screw 38. WVhen the cam 13 is rotated by the handle 321, the head is moved to the left and the latch 36 slides on the latch stud until it snaps into the groove 35. Thereafter the parts remain in this position with the springs 14 compressed and the cutters C in operative position until the latch is released. The releasing mechanism for the latch comprises a trigger 39 which passes through a hole in the block B and protrudes beyond the end of the tap, in such a position that it will contact with the bottom of the hole in the work which is being tapped whenever the tap has gone the predetermined distance. This trigger 39 is provided at its upper end with an inclined surface a engaging a corresponding inclined surface I) formed in a slot 0 in the latch 36. When the trigger 39 contacts with the bottom of the hole, the further advance of the tap presses back the trigger 39 and moves the latch 36 by reason of the action of the inclined faces a and b releasing the latch from the latch stud 341 and allowing the head to snap back under the pressure of the springs '14. This movement of the head withdraws the cutters from the threads so that the tap and the work may then be separated without rotating either piece. The trigger 39 is held from rotating which would result in disengagement of the inclined faces a and b by means of a pin 40 passing through a thimble 41 on the lower side of the head 12 and engaging a slot 42in the trigger 39.

The trigger 39 is made in two pieces the lower of which is designated 45, the two pieces being screwed together. When it is desired to carry the threads nearer to the bottom of the hole the piece 45 is unscrewed and a shorter one is substituted. If the tap stops too near the bottom, a longer piece is put on. This forms a provision for adjustment for depth of hole.

The adjustment to vary the amount which the cutters protrude beyond the surface of the block is accomplished by changing the position of the latch stud 341. As the cut ters wear, the stud is screwed farther into the block, so that the head 12 moves farther to the left as seen in Fig. 1 before the latch engages the stud.

What I claim is 1. In a tap, the combination of an arbor, a body having radial slots therein T-shape in cross section, metal plates on said body forming corresponding slots between their adjacent edges, wedges T-shape in cross section movable longitudinally of said slots and interlocking cutters having slots therein engaging the sides of the slots in said plate and movable radially therein, and a rotatable cam on said arbor for actuating said wedges.

2. In a tap, the combination of an arbor, a body, cutters in the said body movable radially, wedges moving the said cutters radially by movement longitudinally of the arbor, a head secured to said wedges and slidable longitudinally of the arbor, a rotatable cam moving said head in one direction, a spring moving the said head in the other direction, and a latch.

3. In a tap, the combination of an arbor, a body, cutters in the said body movable radially, wedges moving the said cutters radially by movement longitudinally of the arbor, a head secured to said wedges and slidable longitudinally of the arbor, a rotatable cam moving said head in one direction and a spring moving the said head in the other direction, a latch to secure the head in operative position, a trigger passing through said body and engaging said latch.

4. In a tap, the combination with a body having a T-shaped slot therein, cutters in the said slot, radially movable wedges having ribs engaging the groove forming parts of said T-shaped slot, said cutters and said wedges being interlocked by means of corresponding grooves and ribs.

5. In a tap, the combination of a body, radially movable cutters contained in slots in the said body, moving means to operatethe said cutters, a head to which the said moving' means are secured, springs moving said In testimony whereof I afiix my signa- %ea% in olne dilrectign, a cam moving Sablld ture, in presence of two Witnesses.

ea in t e 0t1er irection, an a justa e latch stud, a latch on said head to engage THOMAS KEAN' said latch stud and a trigger passing through Witnesses:

said body to disengage the latch from the JOHN H. PARKER,

said latch stud and release the head. ALICE H. MORRISON.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. 0.

Images