US2076110A

US2076110A - Rotary cutter

Info

Publication number: US2076110A
Application number: US27948A
Authority: US
Inventors: Hugh M Albee
Original assignee: Leavitt Machine Co
Current assignee: Leavitt Machine Co
Priority date: 1935-06-22
Filing date: 1935-06-22
Publication date: 1937-04-06
Anticipated expiration: 1954-04-06

Description

April 6, 1937. H M LBEE I 2,076,110

ROTARY CUTTER Filed June 22, 1935 2 Sheets-Sheet 2 Hugh M flibee,

by 0 144? 6%,.7M, M44 MM Patented Apr. 6, 1937 UNITED STATES PATENT OFFICE ROTARY CUTTER Application June 22,

3 Claims.

This invention relates to cutting tools of the class in which the cutting is done in a plane perpendicular to the axis of rotation of the tool, and in which the tool is urged lengthwise of said axis toward the work during the cutting operation. More specifically, the tool in the present example is intended for use in refacing valve seats such as the seats of pump valves, globe valves and the like, and its general characteristics and mode of operation are similar to those of the rotary cutter which is the subject matter of Letters Patent No. 1,851,613, issued to The Leavitt Machine Company as my assignee.

The present invention deals with a tool of this type having several novel and useful features, among which are: first, the provision of a cutter head having spring portions on which the cutters are mounted and by which the cutters are enabled to yield rearwardly with relation to the cutting plane, thereby preventing chattering and tearing of the valve seat which sometimes characterizes the action of rigid cutters heretofore employed, particularly with some kinds of metal used in valve seats; second, the provision of means to render the spring portions of the cutter head rigid and unyieldable for certain classes of work; third, the arrangement of the cutters in groups, the cutters of each group being arranged one in advance of another, considered with reference to the direction of rotation, the one which is in advance being disposed on a less yieldable part of the spring portion, and the one which is in the rear being disposed on a more yieldable part of the spring portion; fourth, an arrangement of the cutters in groups, the cutters of each group having generally parallel cutting edges which are transverse to the cutting edges of an adjacent group; and fifth, the provision of a clamping plate disposed between and clamping two adjacent cutters against the face of the cutter head, the arrangement being such that the cutters can be adjusted in the directions of their lengths.

The invention will best be understood by reference to the following description when taken in connection with the accompanying drawings of two specific embodiments thereof which have some features in common but which differ in other respects, while its scope will be pointed out more particularly in the appended claims.

In the drawings,

Fig. 1 is a plan of a rotary cutting tool embodying the invention;

Fig. 2 is a side elevation of the same;

Fig. 3 is a bottom plan of the tool;

Fig. 4 is a sectional view on line 44 of Fig. 3;

1935, Serial No. 27,948

Fig. 5- is a top plan of another form embodying some features of the invention;

Fig. 6 is an elevation of the same;

Fig. 7 is a bottom plan of the tool shown in Figs. 5 and 6; and

Fig. 8 is a sectional view on line 88 of Fig. 5.

Referring to the drawings and to the embodiments of the invention illustrated therein by Way of example, and having reference at first to Fig. 1, there is shown a cutting tool comprising a rotatable cutter head It) provided with a central boss l2 having an axial opening l4 to receive a spindle on which it may be mounted for rotation about an axis by appropriate mechanism such, for example, as that which is disclosed in the aforesaid patent.

The head has a face I6 (see Fig. 2) perpendicular to the axis of rotation (and in thiscase interrupted as will appear more fully hereinafter). This face affords a foundation for a plurality of cutters l8 and I8 (see Fig. 3) arranged in groups, each group in the present example comprising two cutters disposed against the face IS, the cutters of each group having their cutting edges generally parallel to each other and transverse to the cutting edges of an adjacent group. In this embodiment the cutters are triangular in cross-section (see Fig. 4) and each has one face which lies flatwise against the face [6 of the cutter head. The remaining two faces of the cutters form an inverted V.

The cutters have cutting edges 20 and 20' and all of the cutting edges lie in a plane perpendicular to the axis of rotation. In this embodiment the cutting edge 20 of the cutter !8 of each group is in line with and radial to the axis of rotation, while the cutting edge 20' of the remaining cutter I8 of the same group is behind the cutting edge 20, considered with reference to the direction of rotation shown by the arrow at the left of Fig. 3, for example.

To secure the cutters to the cutter head while permitting them to be adjusted lengthwise if desired, each pair of cutters is associated with three plates, namely, an intermediate plate 22 and two outer plates 22 all having sloping faces (see Fig. 4) overlying the corresponding sloping faces of the cutters. The intermediate plate is secured in place by clamping screws 24 threaded into the cutter head and the outer plates are secured in place in like manner by screws 24. In the case of the plates 22 the inner faces of the plates lie directly against the face l6 of the cutter head, but in the case of the intermediate plate 22 the inner face of the latter is separated somewhat from the face i8 by a space 26 so that when the screws are tightened the plate 22 serves to clamp both cutters 2t and 253'.

In this form the cutter head is provided with a plurality of arms 28 (see Fig. 1) each having a spring portion 3i] and having also a second portion 32 which is comparatively rigid. The spring portion 38 of one arm 28 (see Fig. 1) underlies the comparatively rigid portion 32 of another arm 28. Associated with each spring portion is appropriate means at will to render said spring portion rigid and unyieldable in the general direction of the axis of rotation. In the present example this means comprises a plurality of screws 34 extending lengthwise of the axis of rotation and having threaded engagement with the comparatively rigid and unyieldable portions 32, and they are arranged to be rotated to engage the spring portions respectively, as will be evident from an inspection of Figs. 2 and 3, to render the spring portions rigid and uniyeldable in the general direction of the axis of rotation of the cutter head.

Thus for certain classes of work, i. e., for operation on certain metals, the spring portions of the cutter head may be rendered rigid and inflexible, while in operating on other metals the screws 34, when backed away from the spring portions, allow the latter to yield lengthwise of the cutter head axis and accordingly permit the cutters to yield correspondingly. Lock nuts 36 threaded onto the screws 3 may be tightened to lock the screws in their proper positions.

In operation, the cutting edge 2!! of each cutter l8 being the one which is in advance, operates to remove some of the metal and it is followed up by the cutting edge is of the second or following cutter i8 of the same group. Moreover, it will be observed by reference to Figs. 2 and 4 that the cutter i8, which is arranged in the rear, considered with respect to the direction of rotation, is mounted upon a part of the spring portion 30 which is relatively remote from a connection 38 between the spring portion 30 and the rigid portion 32, as a consequence of which, when the spring portion yields, the cutter I8, which is the trailing cutter, yields to a greater extent than the cutter l8, which is the advance cutter. This action is found in practice to produce excellent results, particularly on some alloys used for valve seats.

The second form will now be described, reference being had to Figs. 5 to 8 inclusive. In this form a cutter head Gil is provided with a hub 42 for attachment to a spindle by means of which it may be rotated, and it has two arms 44 which together are somewhat in the form of a letter S (see Fig. 5), and the extremity of each arm is provided with a groove 65 (see Fig. 7) to receive a cutter 48 which in this instance is provided with two cutting edges 5% and 52, one in advance of the other and herein obliquely disposed with reference to a radial line from the center of rotation of the cutter head. Each cutter is conveniently secured in place as by a cap screw 54 extending loosely through an opening 56 in the cutter head and threaded into the cutter 48 as shown in Fig. 8. A dowel pin 58 tightly fitted into an opening 55 in the arm 44 and projecting below the lower face of the latter serves as a means for locating the cutter 48 before inserting the cap screw 54.

In this example the extremity of the arm 44 which carries the cutter is sufficiently flexible to constitute a spring permitting the cutter to yield lengthwise of the axis of rotation, but iii this example, as in the one first described, provision is made to render the spring portion of the arm 44 rigid and inflexible. As shown, each arm 44 comprises a web portion 62 having therein an opening 64, herein conveniently circular in form, and from this opening a narrow slot 58 extends to the edge of the web. At one side of this slot is a screw 68 threaded into the web lengthwise of the axis of rotation of the cutter head, and this screw is provided with an integral collar 10 which overlies the slot. When therefore this screw is turned to bring the collar down upon the web 62 the outer end or spring portion of the arm 44 is rendered rigid and inflexible so that the cutter cannot yield lengthwise of the axis of rotation, but when, on the other hand, the screw is backed away from the Web so that the collar on the screw no longer engages the outer extremity or spring portion of the arm, the latter yields slightly lengthwise the axis of rotation. Thus the, tool can be changed instantly from a condition of flexibility to a rigid and inflexible condition depending upon the nature of the metal upon which the tool is to be used.

Having thus described two embodiments of the invention but without limiting myself thereto, what I claim and desire by Letters Patent to secure is:

1. In a rotary cutting tool of the class in which the cutting is done in a plane perpendicular to the axis of rotation of the tool and in which the tool is urged lengthwise of said axis toward the work during the cutting operation, the combination of a rotatable cutter head having a plurality of arms each having a spring portion which is yieldable in the general direction of said axis, said spring portions and said second portions being disposed in part, at least, in parallel planes, a plurality of screws extending lengthwise of said axis and having threaded engagement with said second portions, respectively, and arranged to be rotated to engage said spring portions, respectively, to render said spring portions rigid and unyieldable in the general direction of said axis, and a plurality of cutters supported by said spring portions, respectively, and having cutting edges in a plane perpendicular to said axis.

2. In a rotary cutting tool of the class in which there is a thrust of the tool lengthwise of its axis of rotation and toward the work to effect cutting, the combination of a rotatable head having provision for attachment to a spindle to rotate said head about the axis of the spindle, said head having a portion which is resiliently yieldable lengthwise of the axis and a portion which is unyieldable lengthwise of the axis, said resiliently yieldable portion being supported by said unyieldable portion and having two parts, one of which is angularly in advance of and less yieldable than the other, and two cutters, one mounted on the less yieldable part and the other on the more yieldable part, and arranged to act successively on the same surface of the work.

3. In a rotary cutting tool of the class in which there is a thrust of the tool lengthwise of its axis of rotation and toward the work to effect cutting, the combination of a rotatable head having provision for attachment to a spindle to rotate said head about the axis of the spindle, said head having a portion which is resiliently yieldable lengthwise of the axis and a portion which is unyieldable lengthwise of the and the other on the more yieldable part, and

axis, said resiliently yieldable portion being suparranged to act successively on the same surported by said unyieldable portion and having face of the work, the cutter which is mounted two parts, one of which is angularly in advance on the less yieldable part being in line with the 5 of and less yieldable than the other, and two axis of rotation.

cutters, one mounted on the less yieldable part HUGH M. ALBEE.