US1071202A - Expansible bit. - Google Patents

Description

G. P. BUTLER.

EXPANSIBLE BIT. APPLIGATION FILED MAY 14, 191s.

Patented Aug.26, 1913.

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GEORG-.E P. BUTLER, 0F WALLINGFORD,

PATENT OFFTCE.

CONNECTICUT, ASSIGNOR T0 WILLIAM C.

BIDDLE, 0F NEW YORK, N. Y.

EXPANSIBLE BIT.

Specification of Letters Patent.

Patented Aug.. 26,1913.

Application led May 14, 1913. Serial No. 767,551.

To all whom t may concern.'

Be it known that I, Gnonen l). BUTLER, a citizen of the United States, esiding at l/YJ'allingi'ord, county oi' New Haven, and State of Connecticut, have invented certain new and useful Improvements in Expansible Bits, fully described. and represented in the following specification and the accompanying drawings, forming a part o1E the same.

This invention relates to improvements in expansible bits and particularly to an eX- pansible bit which may be used for boring a hole with a reverse taper'.

rThe especial object of the invention is to provide an improved expansible bit, that shall be eilicient in action and durable, while at the same time simple and cheap of manufacture, and in which the cutter shall be laterally adjustable by the rotation of the bit, so as to be automatically adjusted to expand the bore at the proper rate relatively to the speed of the bit, by intermittently advancing the cutter as the bit rotates.

A further object of the invention is to provide an eXpansible bit in which the cutter may be adjusted readily to cut any desired size of hole within its range of sizes, and also may be quickly and easily removed and replaced as, for example to sharpen said cutter or replace it when broken.

`With the above, and some further objects which will be apparent to those skilled in` the art from the description hereinafter given, an eXpansible bit embodying the broad features of my invention comprises a cutter adjustable laterally and reciprocating` means for intermittently feeding said cutter laterally a predetermined amount at predetermined intervals.

A device embodying the best form of my invention comprises a cutter, manuallyoperable means for adjusting said cutter laterally, and a rcciprocatory device arranged to engage and move said adjusting means at intervals, whereby the cutter is fed laterally. By this arrangement, the cutter may be adjusted manually to the desired size without manipulating the reciprocatory device, and in the best embodiment of the invention, the construction is such that the reciprocatory device in its retracted or non-actuating position leaves the cutter adjusting means free for such manual adjustment of the cutter,

whereby unnecessary friction is avoided and the removal and replacement of the cutter is simpliiied.

The invention will now be described in its preferred embodiment as shown in the accompanying drawings, in which- Figure l is an elevation of the complete bit, with the sleeve partly in section. Fig'. 2 is a central longitudinal section of the sleeve at right angles to Fig. l, with the pawl rod and cutter portion of the bit in elevation. Figs. 3, land 5 are cross sections on the lines h-3, 4%, and 5- 5 oit Fig. 2. Fig. 6, is a longitudinal section on the line G of Fig. l, on an enlarged scale. Fig. 7, is a central section at right angles to Fi 6, with the cutter and worm in elevation. F ig. S is a detail section on one side of the pawl rod and ratchet.

Referring to the drawings, l is a bit shank, in the present example shown as provided with the usual squared and tapered socketengaging end integral with the shank, and also having an enlarged bit-head 2, below which is arranged a means for feeding the bit into the material; this means comprising, in the form shown, a gimlet screw 3, above which is a center-cutter having acutting edge indicated at 4, above which is arranged a spiral channel for the escape of the chips from said cutting edge 1l. rl`he center-cutter also may be provided with a scoring-lip 5. Above the center-cutter the bit-heal 2 carries a laterally movable cutter 6 and means for feeding said cutter laterally. ln the embodiment shown the bit-head 2 is ilattened on one side and provided with square dovetailed grooves, and the cutter 6 is formed to fit into said grooves, as will be clear from Figs. 2 and (3 of the drawings. rllhe cutter 6 has the usual cutting edge 7 and scoringlip 8, the cutting edge projecting from the plane of the front surface of the cutter and being connected therewith by a curved surface over which the chips from the said cutting edge 7 are gradually deflected. Just above the said cutter 6 the bit-head is provided with means ior adjusting and holding the cutter, this means, in the embodiment shown, consisting of a worm 9 arranged with. its axis transverse to the axis oft the bitshank, said worm being arranged in a socket in the bit-head and having its lower side in mesh with a worin-rack 10, Fig. 7, formed on the upper edge of the cutter l6. At one end of the worm 9 is a ratchet wheel 11, the worm and ratchet wheel being carried by stub-shaft 13, mounted in the bit head.

`he socket in the bit-head, in which the worm with its connected parts is mounted, has a reduced bore at its inner end in which the inner end of stub-shaft 13 is rotatable, and at its outer end is counter-bored, said counter-bore portion 14 being threaded to receive an externally-threaded collar 15, which can be slipped onto the stub-shaft 13 and then screwed into the counter-boie of the socket, the collar thereby serving as an outer bearing for the stub-shaft 13. For the purpose of allowing the worm to be manually operated the stub-shaft 13 has its outer end suitably Jformed to receive an operating tool, as for example, by providing the outer face of the stub-shaft 13 with a slot as shown, into which the end of an ordinary screw-driver or the like tool may be inserted. The collar 15, Fig. 2, also is preferably formed to be engaged by a suitable tool for rotating it, when screwing it into or unscrowing it from the counter-bore, as` for example, by slotting the outer face of said collar to receive a screw-driver.

It is to be noted that in the preferred embodiment of the invention illustrated in the drawings, the outer and the stub-shaft 13 do not project beyond the surface of the bit-head, the outer surface of the collar being curved and continuous with the outer surface of the bit-head, while the outer face of the stub-shaft is substantially tangent to the curved outer surface of the collar, whereby a substantially smooth exterior is provided.

lt will be seen that by applying a screwdriver to the slotted end of the stub-shaft 13, the latter, and with it the worm and the ratchet wheel, may be rotated, and owing to the engagement of the worm with the worin-rack of the cutter, the latter may be moved inward or outward, assuming that the ratchet-wheel is not engaged in any way. Furthermore, by running the cutter out to its extreme limit, the teeth of its wormrack will finally leave the worm-wheel and the cutter may then be freely drawn out of the guideways of the head, so that the cutter may be sharpened and then replaced by a reversion of the steps described. In the best embodiment of the invention, the` pitch of the worm is so hat that end thrust on the cutter cannot cause the rotation of the worm, that is to say, the worm and the worm-rack on the cutter constitute a selflocking adjusting means or device so that the cutter cannot be moved from any position to which it is adjusted except by purposely rotating the worm by a tool applied to the stub-shaft 13.

For the purpose of actuating the worm faces of the collar 15 I i sheaths must during the rotation of the bit, in order to automatically produce a reverse taper in the hole being bored, suitable means is provided whereby an intermittent rotation may be given to the worin. This means comprises, in the present example, the ratchetwheel 11 and a device for converting rotary motion of the bit into reciprocatory motion and comprising a reciprocatory member en- Oaging the ratchet-wheel to cause the de- :3. a sired intermittent rotation of the worin. ln the embodiment shown in the drawings, the

device for converting rotary into reciprocatory mot-ion comprises a cam device and a reciprocatory member arranged to engage the cam device, one of these two devices being stationary and the other having an angular motion relative to it. 1n the specitic construction shown in the drawings, the bit-shank is slotted longitudinally in line with the ratohet-wlieel 11, and in this slot is slidably mounted a pawl-rod 16, which is provided with a shoulder 17, Fig. S, arranged to engage the teeth of the ratchet-wheel. rlhe upper' end of the pawlrod has a laterally or radially projecting pin 13, which may carry an antifriction roller 19 arranged to be engaged by a suitable cain device. ln the present example this cam device is formed as follows: The bit shank is enlarged in diameter at two places as indicated at 2O and 21, Figs. 1, and 2, these enlargements serving as collars, between which are placed t-wo tubular sheaths Q2 and 23 having those ends next to the respective collars 2O and 21 square, while the ends of said sheaths which are adjacent to each other are sloped to form cam edges 24, said edges being parallel to each other and separated a distance about equal to the diameter of the roller 19 on the pawl-rod, so that said rolle may travel in the space between said cam edges 24. As the interior diameter of each sheath 22 and 23, is substantially equal to the external diameter' of the bit-shank, and as the enlargements or collars 2O and 21 are, in the present instance, integral with the bit-shank. each of the said be split longitudinally as shown in Figs. 1 and 3 in order to permit them tobe put in place on the shank. @ver the bit-shank is placed a sleeve 9.5, arranged to surround both collars 20, Q1 and to inclose the tubular sheaths. The exterior surface of this sleeve 25, is milled and serves as a hand-hold in operating the device for boring holes with a reverse taper. The sleeve is held in place on the shank while permitting rotation of the bit-shank relative thereto, and the sleeve is attached to the sheaths 22 and 23 by machine screws 26, 2T, threaded into the sleeve from opposite sides with the ends of the screws entering holes in the respective sheaths,

It will be obvious that, when the bitlSO shank is rotated, the pawl-rod 16 will be carried around with the bit-shank. If the sleeve 25 is free to rotate with the bit-shank no reciprocating movement of the pawl-rod will occur, but if said sleeve be held sta* tionary, the sheaths also will be stationary, and as the pawl-rod and its roller 19, rotate with the bit, the roller 19 and pawl-rod 1G will be reciprocated by the cam 24 and the pawl-rod will operate theratchet-wheel to rotate the worm and secure the outward feed of the cutter. With the cutter shown, which is self-feeding outward, the worm acts to hold the critter' against outward movement, and when moved releases the cutter for the outward feed. rlhis is prefern able as it reduces the wear on the parts, but other forms of cutters may be used and the worm feed the cutter by forcing it outward.

For the purpose of allowing the pawl-rod to yield and thereby clear the teeth of the ratchet-wheel on its stroke, the pawl-rod is fitted with a slight radial clearance beneath the lower sheath and the sleeve, so that it may move radially outward to a slight extent during its reciprocation, and for the purpose of holding the said pawlrod yieldingly against the ratchet-wheel a suitable spring device is employed. In the present example, this spring device consists of a substantially circular spring 28 retained in a circumferential groove 29, formed in the lower collar 21, and covered by the lower end of the sleeve, this spring 28, having one end inserted in a radial hole in the shank and the other end arranged to rest upon the pawl-rod, as will be clear from Fig. 5. Any suitable friction or other holding device may be used for preventing the ratchet-wheel being rotated backward by the pawl-rod 16 as the latter is withdrawn. As shown, this result is secured by a coil spring 30 pressing against the end of the stubshaft 18 and pressing the worm 9 against disk 15.

It is to be understood that the bit disclosed may be used as an ordinary expansible bit for boring holes of different sizes within range of the adjustment of the cutter G. The cutter may be adjusted either inward or outward by turning the stub-shaft 13 and its attached worm in the proper direction, which is possible when the pawlrod 16 is fully retracted upward because at this time the pawl-shoulder 17 is out of the orbit of the teeth of the ratchet-wheel, thus leaving the said ratchet-wheel free to rotate in either direction. During the use of the bit for boring straight, that is, nontapering holes, the sleeve 25 is not held, but is allowed to turn with the bit-shank, whereby the pawl-rod is not reciprocated. When it is desired to bore a tapered hole the cutter 6 is first adjusted to the desired starting position and during the rotation of the bit, the sleeve 25 is grasped by the hand of the operator and held stationary, whereby the tubular sheaths and are also held. tionary, thus causing the roller 1S) on the pawl-rod to ride around in the cam slot formed between the ends of the tubular sheaths. In this way the pawl-rod is rcciprocated. The rate of reciprocation of the pawl-rod depends on the particular configuration of the cam slot. In the example given, the cam slot is a simple incline up and down and therefore there is only one reciprocation for each rotation of the bitshank. The result of this movement of `the pawl-rod in the specific example illustrated is to move the ratchet-wheel one tooth for each rotation of the bit, thereby rotating the worm and feeding the cutter laterally outward a predetermined amount for each rotation of the bit-shank, the extent of this predetermined feed depending upon the number of teeth of the ratchet-wheel. Instead of feeding the cutter outward to gradually enlarge the hole, it will be understood that the bit may readily be arranged by proper construction and arrangement of ratchet-wheel, worm and rack, or substitution of parts, to feed the cutter laterally inward and form a hole tapering inward from a'largcr to a smaller diameter. It is obvious that interchangeable cutters of different sizes or different forms may be used, so that by substitution of cutters, a very wide range of work may be provided for.

It will be seen from the drawings, that the specic embodiment of the invention is a compact, durable device readily operated, adjusted and sharpened, but it will be understood that the invention is not to be limited to the exact construction or arrange ment of parts shown, but that modifications may be made therein without departing from the invent-ion.

Having thus fully described my invention, what I claim is :h

1. In an expansible bit, the combination, with a bit-shank and a laterally-adjustable cutter carried thereby, of manually-controllable reciprocatory means for intermittently feeding said cutter laterally a predetermined amount at predetermined intervals by the rotation of the bit.

2. In an expansion bit, the combination, with a bit-shank and a laterally-adjustable cutter carried thereby, of manually-operable means for adjusting said cutter, and man ually-controllable reciprocatory means for intermittently feeding said cutter laterally a predetermined amount at each revolution of the bit-shank.

3. In an expansible bit, the combination, with a bit-shank and a laterally adjustable cutter carried thereby, of a manually-operable self-locking means for adjusting said cutter laterally, and manually-controllable reciprocatory means actuated by the rotation of the bit-shank for actuating said adjusting means, whereby the cutter is fed laterally.

4. In an eXpansible bit, the combination, With the bit-shank, and a laterally adjustable cutter carried thereby and having a Worm-rack, of a Worm carried by the bit and engaging the Worm-rack, a ratchet- Wheel connected to the Worm and arranged to drive the saine, a paWl-rod engaging the ratchet-Wheel, and a cam-device arranged to reciprocate the paWl-rod when the bit is rotated.

5. In an expansible bit, the combination, With a bit-shank, a laterally adjustable cutter carried thereby and means for adjusting said cutter' laterally, of a means including a reciprocatory device for actuating said cutter-adjusting means, ried by the bit-shank, and cam-mechanism arranged to be held stationary and thereby to reciprocate the i'eciprocatory device.

6. rIhe combination with a bit and a laterally adjustable cutter carried thereby, of a rack on the cutter, Worm 9 engaging the rack, pawl Wheel 1l on the Worm shaft, paWl-rod 16 for rotating the Wheel, and

said means being carmeans for reciprocating the paWl-rod by the rotation of the bit.

7. The combination With a bit and a laterally adjustable cutter carried thereby, of a rack on the cutter, Worm 9 engaging the rack, pawl Wheel 1l on the Worin shaft, paWl-rod 16 for rotating the Wheel, a cam engaging the paWl-rod, and hand sleeve 25 for holding the cam stationary or permitting it to rotate With the bit.

V8. The combination with a bit and a laterally adjustable cutter carried thereby, of a raclr on the cutter, Worm 9 engaging the rack, paWl-Wheel l1 on the Worm shaft, paWl-rod 16 for rotating the Wheel, sectional sheaths 22, 23 inclosing the bit stem and forming cam 24 engaging the paWl-rod, and hand sleeve 25 detachably connected tc the sheaths vfor holding the cam stationary or permitting it to rotate With the bit.

In testimony whereof, I have hereunto set my hand, in the presence of tivo subscribing Witnesses.

GEORGE P. BUTLER.

IVitnesses C. J. SAWYER, T. I?. Kurier.

Copies o1 this patent may be obtained for ve cents each, by addressing the Commissioner of `Patents,

Washington, '.D. C.

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