US2442424A

US2442424A - Center cut shear

Info

Publication number: US2442424A
Application number: US556967A
Authority: US
Inventors: Francis L Mcgary; Charles E Mcgary
Original assignee: Individual
Current assignee: Individual
Priority date: 1944-10-03
Filing date: 1944-10-03
Publication date: 1948-06-01
Anticipated expiration: 1965-06-01

Description

June 1, 1948. F. L. McGARY' ETAL CENTER CUT SHEAR Filed Oct. 3, 1944 Patented June 1, 1948 NITED STATES. PATENT OFFICE CENTER CUT SHEAR Francis L. McGary and Charles E. McGary, Hardinsbm'g, Ky.

Application October 3, 1944, Serial No. 556,967

11 Claims. 1

The invention relates to a center cut shear, of the type used in cutting sheet rnetal, and it is an object of the invention to provide an implement by means of which it is made possible to v punch. a hole in a sheet of metal and then cut in any direction desired, with any desired changes in direction of cut, or to cut off down spouting. to cut off sheet metal pipe of all types and in any shape, and in general to provide a shear of great versatility as compared with shears such as here- Another object is to provide a shear that is particularly suited to enter the wall of a building constructed of sheet metal, and to make incisions therein, as for Windows and the like.

Referring now to the drawings, which are made a part of this application and in which similar parts are indicated by similar reference characters:

Fig. 1 is a side elevation of a preferred form of the invention, 7

Fig. 2, a top plan of the same, and

Fig. 3, a bottom plan.

In the drawings, reference character Ill indicates a shear member having parallel cutting edges at its forward end and having at opposite sides thereof blades II I I coacting with said cutting edges. said blades being pivoted to the handle I!) at I2. The blades II, II are turned upward at the rear of the pivot I2 and a handle I3 is pivotally connected to them at I4. A link 45. pivotally connected at IE to the upper handle and at I? to the lower one, serves to provide a sort of toggle-like action for the operation of the shear.

The upper side edges of theforward portion of shear member ID at opposite sides of its flat upper face are formed as cutting edges I8, I8, as above stated, to coact with the corresponding inner edges of the respective shear blades H, II. the under faces of the blades being inclined upwardly toward their outward edges, as shown in Fig. 1. At the under side of the forward portion of the member Ill there are formed oppositely inclined faces I9 so that the end part is approximately V-shaped in section, and the said end tapers gradually to a point at l9, Preferably the angle formed by each face I9 with the adjacent fiat side face of the blade grows steeper toward the point I9, the three faces thus forming an elongated taperedpoint.

This sharp point enables the user to stab the end of the tool through sheet metal and the like. A narrow strip is cut out of the sheet between the blades I I, II, and this aids in cutting in other than straight lines through a piece of work, since this strip can readily be bent out of the way of the blades, so that almost any desired shapes can be cut out of metal sheets, sheet metal spouting, and the like.

At the grip end of handle I3 the handgrip portion is bent to the left (looking backward along the tool in Fig. 2 from the point I9) away from the median plane passing through the two handies and perpendicular to their pivots, and then is bent back again so that the extreme outer corner. as at 2|, lies approximately in the same plane as the righthand face of the main or body portion of said handle and the grip portion lies I mainly at the left of the median plane in Fig, 2. The grip portion is also twisted so as to turn the same about the aixs of said handle and to throw the bottom member 22 of the rip outward with relation to the upper member 23, thereby to accommodate the grip most effectively to the thumb of the user.

The grip portion of the handle Ill is also offset laterally with respect to its body portion, and is bowed outwardly so that substantially all of the parts 24, 2 5 lies at the right of the median line or plane of the shear in Fig. 2 and, in fact, at the right of a plane passing through the righthand face of the bodyportion of the handle I0. Preferably a swell is provided at 25 on the working faceof grip member 25 to fit the fingers, and a hole 21 is provided in advance of the main finger opening, whereby the forefinger of the user may fit conveniently and comfortably into said hole. This opening for the forefinger is useful in providing convenient means for control of the shear, when the hand is relaxed, as in pushing the shear forward after a stroke to locate it for another stroke, and for other like operations. The hole is formed in or just back of the straight portion of the handle. In some shears the forefinger lies in front of the grip since the finger hole is too small to contain all of the fingers, and when in that location is conveniently employed for pulling the shear back from the work, but not for pushing the shear forward toward the work to take another bite.

By reason of the offset arrangement of the grip portions of the tool handles the working surfaces of the grip portions are caused to lie in proper relation to those areas of the fingers and thumb where the greatest application of force naturally falls, and therefore the tool can be used with maximum effectiveness and with minimum exertion on the part of the user. The arrangement of the rocking link, with the pivot of the link close to that of the handle and the movable blades I l, l I, and so located that the line through-points '4, I6 and H straightens as the tool closes, also makes for easy and efiective operation of the tool. It will be obvious to those skilled in the ar that many changes may be made in the device,

handle pivoted to the blades of .said pair above and. rearwardly of said pivot, a link .pivoted to .said second-named handle rearwardly of itspivotal connection to said blades, and a pivot .for

. .said .link onsaidfirst-named handle rearwardly of.-and below its pivot on .thelsecond-named handie. 2. A shear comprising a blade, a handle rigid therewith, a. blade :pivoted to said handle, a handlepivoted to the second-named blade above and rearwardly of thepivotal connection of the v.lelade to the first-named handle, and a link connecting said handles,.said link being pivoted to the second-named handle rearwardly from. the, pivotal connection between the handle and said second-named blade and bein pivoted to the first-named handle rearwardly of and belowits pivot'to thesecond handle.

3. A shear having a blade provided with flat parallellside ,faces, and av flat upper face, said blade also. havinginclined flatfaces intersecting the upper fiat face to provide therewith a tapering point, said inclined faces meeting at the bottom oflthe blade to form a cutting edge'gradually increasing in. obtnseness and .in distance from said .flat upper face, and a blade coacting with the first-named blade.

4. A shear as in.,.claim 3, the front end of said fiatface being V -.shaped, and coacting blades at opposite sides of the first-namedblade, said coacting blades terminating. approximately at the base ofsaid V-shaped portion.

5. A shearcomprising abladehaving a flat upper. face at its iorwardend with the cutting edges at the sides of saidface, and having oppositely beveled flat faces belowsaid .cutting edges,

.the bevels. on said'facesmeeting at the bottomof the jaw to form a cutting edge and the jaw tapering to a .point,,said jawbeing triangular in secti-on and increasing progressively in depth back of said point to form a cuttingedgecoacting .with

the first-named cutting edges, so that the for- V ,ward, ends of the side jaws can coact with the firstnamed jaws in punching a hole in sheetmetal or the'like.

8..IA device as in claim 5, including auxiliary blades at opposite sides of the first-named blade, the auxiliary blades terminating at the forward end-of the side cutting edges of the first-named blade, and tapering toward said blade at their forward ends, so as to coact with the point thereo't'in punching a hole. '9. A. shear as in claim 5, including a blade at each. side of the first-named blade, the second- .narned blades being pivoted to the first-named bladerearwardly of the rear end of its lower cutting. edgev and terminating. at the forward end of the first-named cutting edges, so that the for- ,upper face and oppositely beveled flat side faces,

the bevels of the blade merging at the underside of said blade to form a cutting edge and meeting with said upper face at the end of the blade to form a pointed portion triangular in section extendingiorwardly from the end of said flat upper face.

11. A device as in, claim 10, including a coacting forwardly tapering bladeterminating at the rearend o'f saidpointed portion FRANCIS L. McGARY,

CHARLES E. McGARY.

REFERENCE S CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS .Number Name Date 25,508 Heinisch Sept. 20, 1859 73,255 Buell et a1. May 26, 1863 35,500 Witte Dec. 29, .1868 94,247 Seymour Aug. 31, 1869 325,291 Warner Sept. 1, 1885 430,677 Pearsall June 24, 1890 752,436 Boyd Feb. 16, 1904 760,204 Heinisch May 17, 1904 968,219 Wheeler Aug. 23, 1910 1,357,200 Kiefer Oct. 25, 1920 1,436,603 M Philbert -4 Nov. 21, 1922 2,006,926 Lincoln July 2, 1935 2,207,222 McGary July 9, 1940