US2688791A

US2688791A - Cutting-off blade

Info

Publication number: US2688791A
Application number: US358056A
Authority: US
Inventors: John M Luers; Clemens Mount; Shephard Donald
Original assignee: LUERS
Current assignee: LUERS
Priority date: 1953-05-28
Filing date: 1953-05-28
Publication date: 1954-09-14
Anticipated expiration: 1971-09-14
Also published as: GB740313A; FR1094288A

Description

Sept. 14, 1954 J. M. LUERS ETAL CUTTING-OFF BLADE Filed May 28, 1953 IN V EN TORS 6m /2 4 5 BY 20/7414 Jfiyimd Patented Sept. 14, 1954 CUTTING-OFF BLADE John M. Luers, Mount Clemens, and Donald Shephard, Memphis, Mich.; said Shephard assignor to said Luers Application May 28, 1953, Serial No. 358,056

2 Claims.

This invention relates to improvements in cutting-01f blades, and refers particularly to cutting-off blades having preformed cutting sur faces. In United States Patent Number 2,176,265 is disclosed a blade of this general order, however since that time a great demand has arisen for blades with which to cut off stock of larger diameters than heretofore. Consequently such blades usually project a greater distance from their holders and should therefore be wider than heretofore to withstand the greater strains to which they are subjected. Moreover in order to avoid excessive heating as the depth of the cut increases the cross sectional form of the preformed cutting surface must be such that as the chips burst from the stock and expand they will not jam or bind in the cut but are readily breakable or actually separated intermediately of their width.

It is an object of this invention to provide a cutting-off blade of novel shape having a preformed cutting surface of such cross sectional form that the cuttings or chips are readily breakable or actually severed intermediately of their width as they are removed from the stock so that they will not bind or jam in the cut and cause excessive heating.

Another object of the invention is to provide such a cutting-off blade wherein the cross sectional form of the cutting surface includes outer portions extending generally downwardly and inwardly from its opposite lateral margins, and

wherein a depressed central portion of the cut-' ting surface connects the said outer portions.

A further object of the invention is to provide such a cutting-off blade wherein the said outer portions are usually somewhat concave or hollow ground transversely.

Having thus stated some of the objects and advantages of the invention we will now describe it in detail with the aid of the accompanying drawing wherein the size of the blades is exaggerated for the sake of clarity. In the drawing:

Figure 1 shows a side view of the blade, and

Figure 2 is an end view thereof.

Figures 3, 4, 5 and 6 show modified forms of the preformed cutting surface, and

Figure 7 shows a side view of a blade, on a smaller scale, and a piece of stock being cut thereby.

Referring to the drawing, l designates a blade which is initially at least of greater length than height and is relatively narrow. This blade includes a body 2 having opposite sides 3 which are usually parallel and formed integral with and 2 extending along one margin of the body throughout its length is a head 4 wider than the body and projecting laterally beyond the sides of the latter. The opposite sides 6 of the head 4 are inwardly inclined from the cutting surface toward the junction'of the said head with the body 2. One extremity 1 of the blade throughout its height is downwardly and inwardly inclined from the preformed cutting surface 5 to form a cutting edge 8 across the junction of said cutting surface with the said extremity 1. To sharpen the blade it is merely necessary to grind back the extremity 1 thereby gradually reducing the length of the blade and its head.

It will be noted throughout Figures 2 to 6, inclusive, that in cross section the outer portions 9 of the preformed cutting surface 5 are throughout the length of the latter downwardly and inwardly inclined and are preferably concave or hollow ground transversely. Moreover in some cases it is desirable to provide a balanced blade in which case the two outer portions 9 are of the same width and inclination and are substantially identically hollow ground. Then an imaginary line connecting the outer extremities of the two outer portions 9 is parallel and substantially in alignment with the horizontal axis of rotation of the stock A being out off.

The central portion In of the cutting surface 5 is throughout its length depressed and below the outer portions 9. In Figures 2, 3, 4 and 5 the central depressed portion is shown in the form of a single longitudinal groove extending downwardly in the head 4 from the inner extremities of the outer portions 9. The only difference between these embodiments lies in the cross sectional form of the grooves. In Figure 2 the groove is shown having its opposite sides substantially parallel. In Figure 3 the groove is substantially wedge-shaped and has downwardly and inwardly inclined sides. In Figures 4 and 5 the groove in each case is shown arcuate.

In Figure 6 the depressed central portion of the cutting surface 5 throughout the length of the latter includes two transversely spaced parallel grooves II, which are shown of arcuate section, and the adjacent margins of the grooves are connected by a substantially flat cutting face l2. The outer extremities of the grooves ll each merge with the inner extremity of one of the outer portions 9.

In'Figures 2 and 5 it will be noted that the concave or hollow ground faces of the two outer portions 9 of each blade are described about separate axes and their radii are relatively short,

whereas the hollow ground portions shown in Figures 3 and 4 are of less concavity and in each case the two outer portions 9 of each blade are described about a common axis.

The highest point, or points, of the preformed cutting surface, in the present instance the outer extremities of both outer portions 9, must lie substantially horizontal alignment with. the axis of; the. stock A, and the. permissible vertical distance of the lowest point, or points, is relatively limited, otherwise uniform cutting action. across the width of the blade would not result; and if the aforesaid vertical distance were toogreat there is a probability that thevblade would be broken in operation. It is therefore necessary to form the various sections of the preformed cutting surface within a limited. vertical depth so that chip clearance may occur, and so that the chips are either transversely separate from one another when cut or are readily breakable transversely of their width as. they burst from. the stock.

It is however essential, particularly in. a relatively wide head as indicated in Figure 6, that aplurality of cutting edges be provided and which are disposed atdifferent distances from the horizontal plane: of theaxis above referred to in. order to provide several relatively narrow cuts in the stock for the purposeset forth. in Patent No. 2,176,265, above referred; to..

Thus in the structure of Figures 6- and 7i and as. particularly shown in Figure 6, the two: opposite outer portions 9 the. two grooves Li, and the mid-portion [2 provide five cutting. edges, all of which are disposed beneath the said plane but sufficiently close thereto. as to provide uniform cutting action across the width of the blade.

Whilein the foregoing the preferredv embodiments of. the invention have. been described and shown, itis. understood that further alterations and modifications may be. made thereto. provided the said alterations and modifications fall within the scope of the appended claims.

What we claim is:

1. A blade for circumferentially cutting through a relatively large diameter cylindrical piece of stock; comprising an elongated body, a head extending along one side of the body, said head being of greater width than said body with the; opposite side walls. thereof slightly converging toward the opposite side of said body, a preformed cutting surface on the outer edge face of said head, the cross-sectional form of said cutting surface including laterally opposed outer portiona which! extend inwardly and downwardly from. the said side walls of the head at equal angles to a horizontal plane including the axis of said stock inoperative position of the blade and in which plane, the junctions of said portions and side walls are disposed, a central portion slightly below said plane and parallel therewith, and a. pair of laterally spaced. grooves the adjacent inner edges of whose: walls are co-extensive with the opposite edges of said central portion and the outer edges of whose walls are co -extensivewith the inner edges of! said; laterally opposed outer portions, for the: purpose set forth.

2'. The structure according to claim 1,. wherein the surfaces of said laterally opposed: outer portions are hollow ground, and the. said grooves being: of transversely arcuate form with the. outer edges thereof. substantially in the plane of said central portion,

References Cited; in the file ofthis patent UNITED STATES Number Name Date 1,738,912 Luers Dec. 10,. 1929 2,176,265 Luers Oct. 1.7, L939 2,344,442 Luers Mar. L4,. 1944 2,424,473 Luers. July 22,.194'7