US1408706A - Built-up cutting tool - Google Patents

Description

J. LONG.

BUILT-UP CUTTING TOOL.

APPLICATION HLED 020.22. 1919.

Patented Mar. 7, 1922.

ATTORNEY FIGQ PATENT OFFICE.

JAMES LONG, OE COVENTRY. ENGLAND.

BUILT-U1? CUTTING TOOL.

Specification of Letters Patent.

Patented Mar. 7, 1922.

Application filed December 22. 1919. Serial No. 346,658.

To (ZZZ w 7mm it may concern Be it known that I. Janus Lone, a subject of the King of England. residing at Coventry, in the county of Warwick, England, have invented certain new and useful Improvements in Built-Up Cutting Tools, of which the following is a specification.

This invention relates to built-up milling cutters, reamers, and the like of the type in which the body portion is provided with longitudinally disposed grooves in which the cutters are held and have contact with their side and bottom portions, and it has for its principal object to provide improved means for securing the blades in the bodies of the cutters, and, in the case of reamers, to provide for appropriate movement of the blades in the bodies to constitute an ad.- justable or expansible cutting tool.

According to this invention the body of the cutter has formed in it grooves of uniform dovetail cross-section, (the wider por tion nearest the centre of the body), that is to say, grooves whose bottom edges are parallel to one another and whose sides are of a constant width apart along lines parallel with their bottom edges, and in these grooves the cutters are held by a wedge-action. Where it is desired to secure the cutter against movement or subsequent adjustment, such wedge action may be obtained by giving the cutter throughout its length only such a degree of taper as is required to ensure a driving fit in the groove.

For an adjustable reamer the depth of the grooves progressively increases from the end of the reamer body, and a wedge is employed side by side with the cutter and is adjustable lengthwise of the groove. the combined cross section of cutter and wedge being such as to fit the groove uniformly from. end to end. Upon'the end faces of the cutters and wedges collectively, bears (preferably by the agency of a washer), an adjusting nut, screw threaded upon the body of the reamer. By this arrangement the adjusting means are confined to one end of the reamer so that at the other end the cutters can project from the body clear of all obstructions to constitute an end or bottom reamer- The manner of carrying out the invention as applied to an adjustable reamer is shewn in the accompanying drawings, in which,--

Figure 1 is a side elevation, r

, Figure 2 is a central longitudinal section through the body of the reamer,

Figure 3 is an end elevation on a larger scale than the foregoing views,

Figure 4:, also to alarger scale, shews a plan of the combined cutter and wedge, of which Figure 5 is an end view, and

Figure 6 shews a perspective view of a modified. detail of construction.

Like letters indicate like parts throughout the drawings.

Formed in the parallel sided body A of the reamer are longitudinally disposed grooves A adapted to receive the cutters B and wedges C. The depth of these grooves A uniformly increases from end to end, as shewn in Figure 2, their sides converging to one another at the upper part of the groove to give to it a dove-tail cross section.

It is to be understood that in forming these grooves their CIOSS-SGCCIOII is, with reference to their bottom surface, uniform from end to end, that is, their bottom edges are parallel to one another and their sides are of a constant width apart along any lines parallel to their bottom edges, but, obviously, by reason of their gradually increasing depth, the width at the upper edges of the grooves (as seen in Figure 1) diminishes as the depth of the grooves A? increases.

The manner of forming the grooves A is preferably such that the angle X which each side of thegroove makes with the contiguous part of the bottom is a right angle. not only facilitates fitting the cutters B and wedges C in the grooves. but also avoids the necessity for a cutting-tool of special form, it being thus possible to use an ordinary sides-and-face type milling cutter in the manner hereunder described, which thus gives rise to the particular form (i. e., a fld-t tened V form) of the bottom of the groove as shewn in the drawings. Obviously, how- This.

ever, if desired the bottom of the grooves A the same tool, after resettingv the reamer body in the machine so that one of the side walls of the groove just formed will be remit to constitute with the opposite s de of the groove a dove-tail cross section. As re sult of this, the finished groove A has two faces at the bottom part, inclined to one another but each at right angles to its adjacent side of the groove. In cross-section one side a of the groove is substantially parallel to a radial line extending from the centre of the reamer body to a position midway between the top edges of the groove. while the other side of the groove is inclined considerably to the radial line aforesaid. Against this latter side and the adjacent bottom surface ofthe groove the respective faces B and B of the cutter B, which has in all four faces, closely fit. Preferably some clearance (not shewn) is provided between the next face B of the cutter and the adjacent face of the bottom of the groove, so that only the right-angled surfaces B B require fitting.

The last face B of the cutter is adapted to co-operate with the inclined face C of the wedge (l. (which latter is of rectangular cross-section), in such manner that when the cutter B and wedge C are together inserted in the groove A they bear upon the bottom thereof and closely fit the sides from. end to end of the groove.

It will be seen by reference to the drawings that the action of the wedge C is to thrust the cutter B firmly against the side andbottom of the groove A and the clearance given to the side B of the cutter, as above mentioned, ensures this actlon taking place.

The edge B of the cutter B stands above the edges of the groove A -to form the cutting edge of the reamer, and the wedge C is adjustable lengthwise of the groove.

The inner end of the reamer body A is reduced somewhat in diameter and is screwthreaded over a portion A of the so reduced part, the remaining part A between the screw threaded part and the body A being left plain. The grooves A? are prolonged into this screw threaded part A3, and the cutter B and wedgeiC are of a length to extend beyond the end of the plain. part A. into the screwed part A by an amount equal to that required for theirrange of adjustment lengthwise. V

The inner ends of the cuttersand wedges aresquared off so that they can be uniformly acted uponby an adjusting nut D carried upon the screw-threaded part A? and provided with slots D or the like by, which it can be rotated, a washer orcollar E being r inserted between the cobperating faces of the nut and cutters. To prevent rotation of the collar E during adjustment of the nut D, slots Eflor the like may be providedfor engagement by a spanner, or. if desired, a

pin or feather might be provided on the inner periphery of the washer to engage a. groove in the reainer body.

It will be apparent that when the rearner is adjusted by the longitudinal movement of the cutters, their cutting radius will be increased in accordance with the longitudinal inclination of the bottom of the groove to the axis of the reamer.

As the adjustment acts positively in one direction only, that is to increase the. cutting radius, it is evident that adjustment in the reverse direction can be accomplished by simply slacking back the: nut D as far as required and tapping on the outer ends of the cutters and wedges to return them against the face of the collar E.

means of the wedge any required degree of tightness of fit of the cutter B can be obtained in the groove A As the latter is of uniform section throughout its length, no changein the fit will takeplace during adjustment of the reamer, provided. no .rel ative movement of cutter and wedge occurs during such adjustment. Such relatlve movement is avoided by accurately squaring off the innerends of the cutter and wedge after the latter have been adjusted to a correct fit in the groove, so that they may both move together under the action of the nut An important feature in this vmethod of fitting the cutters is the ability to take up, by means of the wedge, any slackness of the cutter due to prolonged wear. After such, 95 adjustment for wear it will be obvious that the end surfaces of the cutter and'wedge must again bemade flush with one another, as when originally squared off in the first instance. In inserting the wedge and cutter in the groove it is obviously preferable that the thin end of the wedge should be towards the adjusting nut D so that after adjust ment the wedge, instead of the cutter re quires facing off. i i

To prevent the wedges being drawn from the grooves, if the reamer grips fast in use and has to be pulled endwiseto 'free it, screws F may be sunk in the body A, to en gage with their heads the elongated notches C? formed in the outer edgeof the wedges C. This screw F would; require to be slacked back somewhat when the reamer'was eX- panded to allow for the resultant rise of the wedge in the groove. r 1

If desired, in place of the plain collar or washer E, the modified form, G, 'Figure'tl. may be employed. This is provided with projections G adapted to enter the grooves A thus preventing its relative rotation on 120 the reamer. These projections G may also be extended at G from one of the end faces of the collar tobear on the ends of the cutk ters and wedges,their length being made equal to the'amount of the longitudinalad- 125 justment provided for the cutters B'. .By this arrangement only, the threaded part A of the reamer body need be reduced below the diameter ofthe body A, and thusthe parts of the cutters whichwould otherwise 130 lie in the reduced part A*"'(see Figure 1) can be as well supported as those portions which lie in the part A.

A special feature of this adjustable reamer is that the adjusting means are confined to one end of the cutter, so that at the other end the cutters can project from the body clear of all obstruction, to constitute an end or bottoming reamer.

Furthermore, it will be apparent that by this invention the cutter can be firmly se cured along the whole length of the groove by means which are entirely independent of the adjusting device, and that these means ensure the cutter being always thrust against the bottom of its groove, a condition essential to precise adjustment.

By reason of the wedge section of the cutters, those parts which project from the end of the body possess great lateral stiffness so that the tendency of their cutting-edges to chatter is thereby minimized.

here the invention is applied to built-up milling cutters or the like, the cutters may be firmly secured by means of wedges employed on the grooves as above described. Alternatively, the wedges may be omitted, by fitting the cutters to the grooves and giving to the former just sufficient taper to ensure a driving fit to locate it in position.

What I claim as my invention and desire to secure by Letters Patent is 1. A reamer comprising a body part having out lengthwise therein a groove of uniform cross section with a wide bottom, one ofthe side walls of the groove being parallel to a radial line extending from the center of the said body part midway between the top edges of said groove and the other side wall being inclined to the said radial line, the angles formed by the said side walls with their contiguous bottom part being both right angles; the cutter closely fitting the one side wall and bearing on the bottom of the said groove.

2. In a. reamer as specified in claim 1, a wedge arranged adjacent the straight side wall between the latter and the corresponding straight side of the cutter, the combined cross-section of the said cutter and wedge being uniform and fitting the two sides of the groove from end to end.

3. A reamer as specified in claim 1, in which between the cutter and the other side wall a wedge is arranged and in which the groove progressively inclines toward the cutter-axis from the forward end of the body part toward its rear end, the body part having a reduced portion where the groove approaches the cutter-axis, the cutter and Wedge protruding from the groove beyond said reduced portion, and an adjusting nut being screw-threaded on the said reduced portion so as to bear on the ends of both the cutter and wedge and act thereon simultaneously.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

JAMES LONG. Witnesses:

ALBERT BROWN, ANNIE L. WADE.

Images