Locking hole punch

A locking hole punch for punching holes in metal sheets, particularly metal sheets difficult of access such as metal C-studs, is disclosed. This hole punch comprises an arm member that has a head at the end of an outwardly curved portion and a first handle extending from that curved portion. A first lever member formed in a generally mating outwardly curved configuration is pivotably connected to the arm at the top of the arm handle at a first pivot. A generally straight second lever, which acts as a second handle spaced from the arm handle, is pivotably connected to the first lever member at a second pivot near the first pivot. A toggle member is connected to the second lever at a third pivot and to the arm handle at a fourth pivot. When the arm and second handles are pressed together, the toggle member is driven so that the second, third, and fourth pivots are moved into a straightline alignment so that the punch, which includes a punching pin, is driven into a working position with the head. The toggle member can be further driven into a locked mode, which is releasable by operation of a toggle release device. The punching pin can be adjusted to various lengths from the face of the punch by a pin adjusting mechanism. The hole punch is biased from the working position to an open position.

I claim:

1. A locking hole punch for punching holes through a sheet comprising:

(a) An arm having head means at one end and a handle portion at the other end and an outwardly curved portion between the head and handle portions;

(b) a first lever outwardly curved in configuration and having adjustable punch means at one end with an operating axis transverse to the axis of the handle portion, said punch means including punching pin adjusting means for moving the punching pin relative to the opposing head, pivotably mounted at the other end to the arm at a pivot between the handle portion and its outwardly curved portion, said first lever and said arm pivotably movable about the first pivot between open and working positions, so that in the open position the adjustable punch means is spaced from the head means, and in the working position the punch means cooperates with the head means and said outwardly curved portion and said outwardly curved lever form a closed perimeter, whereby said punch means and said head means can punch a hole in a sheet interposed between them;

(c) a second lever pivotably mounted at one end at a second pivot point spaced from the first pivot on the first lever and having a handle end, said second lever spaced from the handle portion of the arm in the open position and in hand-gripping relation to the arm in the closed position;

(d) toggle means pivotably mounted to the second lever at a third pivot and to the handle portion of the arm member at a fourth pivot point, said second lever adapted to drive the first lever rotatably at the second pivot about said first pivot from the open position to a working punching position when the second lever is driven toward the arm, said toggle means and said second, third, and fourth pivots so aligned to form a power line when the first lever is in the working position; and

(e) biasing means connected between the handle portion of the arm and the first lever for returning the first lever and the second lever from the working position to the open position.

2. A locking hole punch as in claim 1, wherein the adjustable punch means includes a punch member having an inwardly extending punching pin, and said head means includes a head member containing a bore adapted to receive said pin when the first lever is in the working position.

3. A locking hole punch as in claim 2, wherein the fourth pivot is adjustable along the arm member and includes toggle adjusting means on the handle portion of the arm for moving the position of the fourth pivot along the handle portion, whereby the working position of the punching pin may be locked.

4. A locking hole punch as in claim 3, wherein said toggle adjusting means includes a toggle member having one end at said third pivot and the other end at said fourth pivot; said toggle adjusting means further including said handle member having a handle end opposite said outwardly curved portion; and a screw member having opposed inner and outer ends, said outer end having a cylindrical gripping member positioned external to the endmost portion of said handle end, said inner end and said toggle member being in pressure contact at a juncture whereat said toggle member is rotatably movable relative to said handle portion at said juncture, said juncture comprising said fourth pivot, said screw member being threadably mounted in said handle end so that said screw member is movable to a plurality of selected positions in the longitudinal dimension by rotating said gripping member, whereby said fourth pivot is capable of being moved to a plurality of locations along said handle portion.

5. A locking hole punch as in claim 4, wherein said second lever member is adapted to drive said first lever member and said third pivot into the working position with said toggle member as the fulcrum, said working position being whereat said third pivot is aligned on a power line with said second and fourth pivots.

6. A locking hole punch as in claim 1, wherein the toggle means includes a locking shoulder adapted to press against the second level when said toggle means has reached its toggle locking position.

7. A locking hole punch as in claim 6, further comprising toggle release means mounted on the second lever at the handle portion of said lever and rotatably connected to said second lever, whereby moving the toggle release means actuates the toggle means to release the locking hole punch from the locked working position.

8. A locking hole punch as in claim 7, wherein said toggle release means includes a toggle release bar having opposed clamping and release ends rotatably connected to said second lever, said clamping end adapted to receive said locking shoulder of said toggle member when said toggle member is in said toggle locking position, said toggle release bar being rotably movable between first and second positions, where at in said first position said clamping end is spaced from said second lever and said release end is proximate to said second lever, and in said second position said clamping end is pressed to said second lever by said shoulder of said toggle member and said release end is spaced from said second lever, said toggle member being in said toggle nonlocking position when said toggle release bar is in said first position and being in said locking position when said toggle release bar is in said second position, said release end adapted to be manually pressured from said second position to said first position to move said release end from said second position to said first position and thereby move said toggle member from said toggle locking position to said toggle nonlocking position.

9. A locking hole punch as in claim 1, wherein the sheet is that of a metal C-shaped stud.

10. A locking hole punch as in claim 1, wherein said first, second, and third pivots include pivot pins.

11. A locking hole punch as in claim 4, wherein the fourth pivot includes the other end of the toggle member and the inner end of the screw makes pressure contact at a juncture, said toggle member movable by the screw member at said fourth pivot.

12. A locking hole punch as in claim 1, wherein the outwardly curved portion of the arm and the outwardly curved first lever are both C-shaped, so that in the working position a double C-shaped closed frame is formed.

13. A locking hole punch as in claim 1, wherein the punching pin adjusting means comprises a punch head containing an internally threaded bore, a punching pin adapted to be moved along the axis of the threaded bore, an externally threaded member adapted to position the punching pin within the threaded bore of the punch head, and an adjusting knob at the end of the externally threaded member opposite to the punching pin to adjust the position of the punching pin relative to the head means of the arm.