US548385A

US548385A - nelson

Info

Publication number: US548385A
Authority: US
Publication date: 1895-10-22
Anticipated expiration: 1912-10-22

Description

(No Model.)

l Zi Patented 0011.22, 1895.

P. w. NELSON. BIT.

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UNITED STATES PATENT err-cs.

FRANK W. NELSON, OF CHICAGO, ILLINOIS, ASSIGN-OR 0F ONE-THIRD TO LYM-AN B. COE, (9F SAME PLACE.

BIT.

SPECIFICATION forming apart of Letters Patent No.;54.8,38'5, dated October 22, 1895.

Application filed I (1118 8, 1895. seen No. 552,115. (No model.)

To all whom it may-concern.-

Be it knownthat I, 'F'RANK NELSON, a citizenof the "United States, residing at Ohicago, in the county of Cook and State of Illinois, have invented a new and useful Improvement in Bits, of which the following is aspecification.

My invention relates to animprovementin the tool known as a bit, and which involves as its parts a stem'adapted to be inserted at one end into and fastened in a suitable holder or handle and provided'at its opposite pointed end with a rotary cutter.

More particularly stated, my invention relates, primarily, to an improvement in the class of bits having the cutter portion inthe form of a readily removable and replaceable attachment on the stem to afford what may properly be termed a multiple tool possessing the attribute of economy in the matter of original cost and in that of its use by adapting the same stem to be used for outters of many different sizes or varieties.

My object is to provide an improved construction of the cutter-head ofa bit,'and particularly, though not exclusively, of a bit having a removable'and replaceable cutter-head; and my further object is to provide a generally-improved construction of interchangeable bit.

Referring to the accompanying drawings, Figure 1 shows my improved bit by a viewin elevation. Fig. 2 is an enlarged broken sectional view of the same with the gage omitted; Fig. 3, a view in elevation of the gage-holder; Fig. at, an end view of one of the attachable and separable cutter-heads; and Fig. '5, a view of the same in elevation,showing a modificatlon.

A is the stem, provided at one end with a head r, adapted to be inserted into a holder or handle, (not shown,) and which stem should be of uniform or substantially uniform diameter throughout from the head to a circumferential shoulder q, provided near its opposite end, and from which it tapers by preference only to a point as, whence it may be uniform in diameter to the point t, which should be screw-threaded. On the stem is provided a suitable spring-catch device or look B, a desirable construction of which is that illustrated, involving a recess 10, formed in the stem and undercut *in its upper end, while from the lower end of "the recess, which may be straight, extends a slot 13" lengthwise of the stem to the shoulder q, toward which its depth increases. The catch is formed of a bar or strip of sprin'gy metal, provided at one end with ahead 0, conforming inshape to that of the recess p, which it enters, the bar be ing provided toward its lower end with a button 0" and at its lower end with a stud or key 0 projectingat a right angle, and the extent of the projection of which should not be greater than the extent of its play in the slot 19', in order that by depressing'the bar at its button 0 the outer surface of the stud may be brought flush with thecircumferential surface of the stem A.

O is the tubular cutter-head, adapted at will to be applied to and removed from the stern A. It is of the general somewhat cylindrical form illustrated,the longitudinal opening through it conforming to the external contour of the stem from'apoint above the shoulder q to or nearly to the point t, whereby it contains an internalshoulder q to meet the shoulder on the stem. In the body of the head '0 is formed a longitudinal slot 0 at a point to coincide with the key 0 when the head is adjusted on the stem to a point at whichthe shoulders q and q meet, the adjustment being effected by depressing the catch-bar at its button 0' and slipping upon the stem from its point end a head 0 till stopped by abutment of the shoulders, when on releasing the button the key 0 will spring into the-slot 0 and thus engage the cutterhead to hold it in place. Of course the key 0 must not project beyond the external sur-' face of the cutter-head, so that the depth of the slot 0 inthe direction diametrically of the cutter should at least equal the width in the corresponding direction of the stud. In a cutter-head of the larger size the thickness of metal of its body portion may be suflicient to have the slot 0 formed therein, as shown in Fig. 5,.and the spiral rib it about the body portion may then be narrow, as represented in that figure; but in the smaller sizes of the head, the metal of the body portion not being thick enough for a slot 0 as deep as the width of the key 0 as it is required to be for all of the various sizes of interchangeable heads for the tool, the spiral rib n should be accordingly wider, as represented in Fig. 1, in order that the slot 0 may be formed through the additional thickness of metal it affords. The spiral rib starts at theupper end of the head 0 and terminates at the lower end thereof in a knife-edge v, extending from a point at or nearly in line with thelongitudinal center of the head to the outer circumference thereof, where, moreover, behind the plane of said cutting-edge there is provided a downward-extending cutting lip or point to. Close to the central opening through the head 0 on its lower end I provide another and narrower cutting-edge o and behind and adjacent to it on the external side of the arc of which it forms the terminus (andwhich is concentric with the are on which the point to is pro vided) a downward-extending cutting lip or point w. Thus thehead is provided on'its lower end with an innercutter-edge and inner cutter-point and an outer cutter-edge and outer cutter-point, whereby the cutting action is facilitated, and the shavings which are cut must be sufficiently narrow to pass freely along the spiral afforded by the spiral rib u, and thus avoid clogging the tool in boring. It will also be observed that the button 0 is so shaped as to tend to assist the shavings rather than obstruct them in receding out of the hole being bored.

A large number-say twenty or more-01? different sizes of the cutter-heads C, all,how-

ever, having the same'internal shape and di-,

ameter, may be interchangeably used on the same stem A, the shoulders g and q always preventing any tendency in the tapering stem when used in boring to become'unduly tightened by wedging in the head; and thus I practically provide as many different bits as may be adapted for use on the one stem, thereby affording to myimproved tool the attributes of economy hereinbefore referred to.

To gage the depth of penetration of the tool, I provide on the stem a gage D, adjust able for any depth to be bored in proportion to the length of the stem. As shown, the gage comprises a skeleton skirt 'm, terminating at its lower end in a ring m, much greater in diameter than the stem A, and converging toward its opposite end into a circumferentially-grooved collar m which loosely fits aboutthestem; and Z is an annular head surrounding the stem and carrying a set-screw Z, by which to fasten it thereon at any point to which it may be moved, the head being provided with a depending flange 1*, having an inward-extending lipl and reaching only part way about the annular head, whereby it may be engaged with the collar m by inserting the lip Z into the groove thereof, when the whole may he slipped on the stem (as from its upper end) and up or down thereon to the desired point, at which the gage may be fastened by suitably turning the set-screw Z.

What I claim as new, and desire to secure by Letters Patent, is-

1. A cutter-head for a bit provided with an external spiral rib terminating at its lower end in a cutting-edge i), an outer cutting-point w and an inner cutting-edge v on the lower end of the head, and an inner cutting-point w on an arc described on said lower end of the head, said cutting-edge '1) extending in a line tangential to the circle on which said arc is described, substantially as and for the purpose set forth.

2. A cutter-headfor a bit separable from and attachable on the stem of the tool and comprising a hollow head adapted to fit about and be fastened on said stem, the head being provided with an external spiral rib terminating at its lower end in a cutting-edge and having an outer cutting point, and an inner cutting-edge and an inner cutting-point on the lower end of the head, substantially as described.

3. A bit comprising. a stem A provided with fastening means B,acutter-head separable from and attachable on the stem and comprising a hollow head provided with a slot 0 at which it is engaged by said fastening means, the head having an external spiral rib n and terminating at its lower end in a cutting-edge 2; and having an outer cutting-point w, and an inner cutting-edge 'v' and an inner cutting-point w on the lower end of the head, substantially as described.

4. In combination with a bit, a gage D adjnstably fastened upon the bit stem and comprising a skirt-portion m terminating at one end in a ring m and at its opposite end in a grooved collar m immediately and loosely surrounding the stem of the bit, and an annular head Z provided with a set-screw Z and with a flange Z having a lip Z to enter and engage the collar at its groove, substantially as described.

FRANK W. NELSON.

In presence of M. J. FROST, J. H. LEE.

ICE