US3579828A

US3579828A - Heavy-duty metal snips

Info

Publication number: US3579828A
Application number: US837623A
Authority: US
Inventors: Andrew M Hexdall
Original assignee: A M HEXDALL CO
Current assignee: A M HEXDALL CO
Priority date: 1969-06-30
Filing date: 1969-06-30
Publication date: 1971-05-25
Anticipated expiration: 1988-05-25

Abstract

A pair of heavy-duty metal snips is disclosed in which the operative blade is moved by an eccentric pin coupled to the operative handle by a crank arm and link. The other blade is rigid with a flat mounting plate and the link is designed to nest within cooperative portions of the handle. The crank arm, link and eccentric are arranged so that the mechanical advantage transferred to the operative blade increases as it moves toward the closed position.

Description

United States Patent 13,579,828

[72] Inventor Andrew M. Hexdall [56] References Cited do A. M. Hexdall Company, Morris, 111. UNITED STATES PATENTS 985 048 2/1911 Meissner 30/250X [21] Appl. No. 837,623 [22] Filed June 30 1969 3,090,121 5/1963 Chonka 30/251 [45] Patented May 25, 1971 Primary Examiner-Travis S. McGehee [54] HEAVY-DUTY METAL SNIPS 15 Claims, 7 Drawing Figs.

[52] U.S. Cl 30/251, 30/254 [51] Int. Cl B26b 13/00 [50] Field of Search 30/237,

AttorneyWolfe, Hubbard, Leydig, Voit & Osann ABSTRACT: A pair of heavy-duty metal snips is disclosed in which the operative blade is moved by an eccentric pin coupled to the operative handle by a crank arm and link. The other blade is rigid with a flat mounting plate and the link is designed to nest within cooperative portions of the handle. The crank arm, link and eccentric are arranged so that the mechanical advantage transferred to the operative blade increases as it moves toward the closed position.

imAvY-nuTY METAL SNIPS BACKGROUND OF THE INVENTION Cutting heavy-gauge sheet metal with hand-operated metal snips has always been slow and hard. With conventional metal snips the mechanical advantage of the cutting blades decreases as the ships are closed. Consequently, it is necessary to keep the snips pushed well into the metal and to take small nibbling cuts. This results in the handles being spread so far apart that maximum gripping power and ease of operation cannot be achieved. With conventional snips cutting becomes more difficult as the cut proceeds due to interference of the previously cut metal with the snip handles and the necessity to bend the cut metal out of the way.

Accordingly, it is the primary aim of the present invention to provide improved metal cutting snips which incorporate a novel actuating linkage which affords faster, easier and more convenient operation.

It is also an object of the invention to provide a heavy-duty metal snip with cutting blades which not only cut the metal but also spread the cut metal to make advancing the blades for the next cut easier.

A further object is to provide metal snips of the above type with improved fastening means and wear surfaces which permit long periods of trouble-free operation without adjustment.

Other objects and advantages of the invention will become more readily apparent upon reading the following detailed description and upon reference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings:

FIG. 1 is a perspective view of a pair of heavy-duty metal snips which embody the present invention;

FIG. 2 is a side elevation of the snip shown in FIG. 1 with the open position of the Ships down in full lines and the closed position shown in broken lines;

FIG. 3 is an enlarged section taken substantially along line 33 in FIG. 2;

FIGS. 4 and 5, respectively, are sections taken substantially along lines 4-4 and 5-5 in FIG. 3;

FIG. 6 is a section similar to FIG. 5 of the snips in their closed position; and

FIG. 7 is an enlarged fragmentary section taken substantially along line 7-7 in FIG. 4.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Turning now to the drawings, there is shown in FIG. 1 a pair of heavy-duty metal snips 10 which embodies the present invention. The snips 10 include a pair of blades 11 and 12 and a pair of handles 13 and 14 with one of the handles 14 rigidly connected to one of the blades 12 by a mounting plate 15 (see FIG. 3) on which the other handle 13 is pivotally mounted at 16 (see FIGS. 5 and 6). The one blade 12 is disposed substantially at right angles to the mounting plate 15 (see FIG. 3) and defines a cutting edge 17 spaced from and substantially parallel to the mounting plate. The other blade 11 is in the form of a substantially flat, platelike element disposed in face-to-face relation with the mounting plate 15 and is formed with a cutting edge I8 along the lower portion thereof adapted to cooperate with the cutting edge 17 on the blade 12.

In accordance with the present invention, a shaft 20 is journaled for rotation in an opening 21 defined by the mounting plate 15 for operating the blade 12 relative to the blade 11 (see FIG. 3). At one end the shaft 20 carries an eccentric pivot 22 on which the blade 12 is pivotally mounted. At the other end the shaft carries a crank arm 23 which is connected to the handle 13 by a link 24. Preferably, the eccentric pivot 22 is in the form of a key pin which nonrotatably secures the crank arm 23 to the shaft 20. In the preferred embodiment, the handle 13 is formed with a substantially C-shaped forward end 25 with one leg 26 of the C pivoted at 16 on the mounting plate 15 and with the other leg 27 of the C pivotally connected to the link 24. As shown in FIGS. 5 and 6, the crank arm 23 is nested within the C-shaped end of the handle 13.

In further keeping Y with the invention means including a pivot post 30 projecting from the mounting plate 15 and into a slot 31 defined in the blade 12 are provided (see FIGS. 4 and 7) for causing pivotal swinging movement of the blade 12 on the eccentric pivot 22 as the shaft 20 is rotated by the handle I3 through the crank arm 23 and link 24. Moreover, the pivot post 30, eccentric pivot 22, crank arm 23, link 24 and handle 13 are so arranged that the mechanical advantage transferred to the blade 12 increases as it moves from its open position (see FIG. 5) to its closed position (see FIG. 6). This enables an operator to cut heavy-gauge sheet metal with forward ends of the blades 11 and 12 and to maintain a good grip and control on the handles 13 and 14.

Upon reference to FIGS. 4-7, it will be seen that as the snips 10 are closed, the link 24 tends to assume a more nearly right-angle position between the crank arm 23 and the lower leg 27 of the handle 13. This operates to increase the mechanical advantage imparted to the blade 12 as the handles 13 and 14 are closed. It will also be appreciated that as the snips 10 are closed, the blade 12 slides slightly on the pivot post 30 due to the changing spacing between the eccentric pivot 22 and the pivot post 30 as the former is rotated around the axis of the shaft 20.

To open the blades 11 and 12 the snips 10 are provided with a biasing means in the form of a spring 35 between the handles 13 and 14. As shown in FIG. 2, the spring 35 in the illustrated embodiment encircles a pin 36 the head of which is carried in a recess 37 formed in one handle 14. The pin 36 and spring 35 are preferably telescopically received within a tubular guide 38 whose head end is received in a recess 39 formed in the other handle 13. It will be appreciated, of course, that other spring arrangements can also be used without departing from the present invention.

To keep the snips 10 closed when not in use a catch 40 is provided. The catch is pivotally mounted on the handle 14 by means of a screw 41 or the like, and the catch is provided with a hooklike end 42 for engaging a latch post 43 on the other handle 13.

In the illustrated embodiment, each of the handles 13 and 14 is longitudinally split into two pieces 13a and 13b and 14a and 1417, respectively. The C-shaped forward end 25 of handle 13 is secured between pieces 13a and 13b preferably by two-

piece rivets

43 and 44 each of which includes a hardened sleeve with a head on one end and a deformable center pin having a head on the other end. The center pin for rivet 43 ex tends somewhat from its sleeve and forms the latch post on which the catch 40 is hooked as previously noted. The mounting plate 15 is secured between the two pieces 14a and 14b of the other handle 14 by two piece rivets l6 and 46. The hardened sleeve of rivet 16 also serves to pivotally mount the upper leg 26 of the C-shaped handle on the mounting plate 15. A short two-piece rivet 47 also connects the mounting plate 15 to one of the handle pieces 14a at a third location.

The eccentric pivot 22 and the pivot post 30 are also preferably in the form of a two-piece rivet. As shown in FIG. 3, the sleeve 22a of the eccentric rivet 22 acts as a key between the shaft 20 and crank arm 23 and also provides the hardened wear surface on which the blade 12 is pivotally mounted. The hardened sleeve 30a of the pivot post 30 is preferably provided with oppositely facing flats 31a which ride in the sides of the slot 31 and increase the wear surface area therebetween. The fixed length of the hardened rivet sleeves 22a and 30a allow their respective deformable center pins 22b and 30b to be clinched tightly without causing excessive binding between the moving parts. This also permits use of the snips 10 for long periods without necessitating adjustments.

In order to accommodate the crank arm 23 and link 24, the forward end of the handle 14 is hollowed out at 50 in the illustrated snips 10. This construction also serves to shield the shaft 20 from dirt and contamination. While the shaft 20 is shown as journaled directly in the mounting plate opening 21,

it will be appreciated that the shaft could be journaled in an antifriction-type hearing if desired.

The handles 13 and 14 are preferably formed with rear end portions which curve slightly outwardly to provide a comfortable grip for the operator's hand. In the illustrated embodiment, handle 13 is further provided with an outwardly projecting ear 51 which, in use, is adapted to project between the thumb and index finger of the operator and prevent the operators hand from sliding forward on the handles.

From the foregoing it will be appreciated that the snips due to their novel operating mechanism make it possible to cut heavy-gauge sheet metal quite rapidly and easily. Due to the increasing mechanical advantage imparted to the blade 12 as it is closed and the spreading action of the blade 12 on the cut metal, the snips can be advanced smoothly to make either straight slits or cuts curving to the left as desired. It will also be appreciated that'the snips 10 can be made to make cuts in a right-hand curving pattern by simply reversing the side of the snips on which the blades 11 and 12 are located.

I claim as my invention:

I claim:

1. Metal cutting snips comprising, in combination,

a pair of cutting blades and a pair of handles with one of the handles rigidly connected to one of the blades by a mounting plate on which the other handle is pivotally mounted,

a shaft joumaled for rotation in an opening defined by the mounting plate and carrying at one end a crank arm connected to the other handle by a link and carrying at the other end an eccentric pivot on which the other blade is pivotally mounted, and

means including a pivot post projecting from the mounting plate and into a slot defined in the other blade for causing pivotal swinging movement of the other blade on the eccentric pivot as the shaft is rotated by the other handle through the crank arm and link.

2. Metal cutting snips as defined in claim 1 wherein the pivot post, eccentric pivot, crank arm, link and other handle are arranged so that the mechanical advantage transferred to the other blade increases as it moves toward the closed position.

3. Metal cutting snips as defined in claim 1 wherein the one blade is disposed substantially at right angles to the mounting plate and defines a cutting edge spaced from and substantially parallel to the mounting plate.

4. Metal cutting snips as defined in claim 1 wherein the other blade is in the form of a substantially flat, platelike element disposed in face-to-face relation with the mounting plate.

5. Metal cutting snips as defined in claim 3 wherein the other blade is in the form of a platelike element defining a cutting edge along the lower portion thereof adapted to cooperate with the cutting edge on the one blade.

6. Metal cutting snips as defined in claim 5 wherein the lower portion of the other blade adjacent the cutting edge thereof is adapted to engage and spread one part of the cut metal relative to the other part thereby facilitating the advance of the snips for the next cut.

7. Metal cutting snips as defined in claim 1 wherein the forward portion of the one handle is hollowed out to receive the crank arm and link.

8. Metal cutting snips as defined in claim 1 wherein the one handle is longitudinally split into two pieces with the mounting plate secured between the two pieces.

9. Metal cutting snips as defined in claim 8 wherein the mounting plate is secured between the two handle pieces by two-piece rivets including a hardened sleeve having a head on one end and a deformable center pin having a head on the other end.

10. Metal cutting snips as defined in claim 1 wherein the eccentric pivot is in the form of a two-piece rivet including a hardened sleeve having a head on one end and a deformable center in havin a head on the other end.

l1. etal cut mg snips as defined in claim 1 wherein the pivot post is in the form of a two-piece rivet including a hardened sleeve having a head on one end and a deformable center pin having a head on the other end.

12. Metal cutting snips as defined in claim 11 wherein the sleeve is formed with oppositely facing flats adapted to cooperate with the sides of the slot in the other blade to increase the contact surface therebetween.

13. Metal cutting snips as defined in claim I wherein the eccentric pivot is in the form of a key pin for nonrotatably securing the crank arm to the shaft.

14. Metal cutting snips as defined in claim 1 wherein the other handle has a substantially C-shaped open end with one leg of the C pivoted on the mounting plate and the link is pivotally connected to the other leg of the C-shaped end.

15. Metal cutting snips as defined in claim 14 wherein the crank arm is nested within the C-shaped end of the other handle.

Claims

1. Metal cutting snips comprising, in combination, a pair of cutting blades and a pair of handles with one of the handles rigidly connected to one of the blades by a mounting plate on which the other handle is pivotally mounted, a shaft journaled for rotation in an opening defined by the mounting plate and carrying at one end a crank arm connected to the other handle by a link and carrying at the other end an eccentric pivot on which the other blade is pivotally mounted, and means including a pivot post projecting from the mounting plate and into a slot defined in the other blade for causing pivotal swinging movement of the other blade on the eccentric pivot as the shaft is rotated by the other handle through the crank arm and link.

10. Metal cutting snips as defined in claim 1 wherein the eccentric pivot is in the form of a two-piece rivet including a hardened sleeve having a head on one end and a deformable center pin having a head on the other end.

11. Metal cutting snips as defined in claim 1 wherein the pivot post is in the form of a two-piece rivet including a hardened sleeve having a head on one end and a deformable center pin having a head on the other end.

13. Metal cutting snips as defined in claim 1 wherein the eccentric pivot is in the form of a key pin for nonrotatably securing the crank arm to the shaft.