US1737958A

US1737958A - Hammer with adjustable fulcrum

Info

Publication number: US1737958A
Application number: US249345A
Authority: US
Inventors: John W Carlson
Original assignee: Individual
Current assignee: Individual
Priority date: 1928-01-25
Filing date: 1928-01-25
Publication date: 1929-12-03
Anticipated expiration: 1946-12-03

Description

Dec. 3, 1929. J, w, c so 1,737,958

HAMMER WITH ADJUSTALE FULCRUM Filed Jan. 25, 1928 11v VEN 70R J. W. Car/5 on BY A TTOR/VEV Patented Dec. 3, 1929 UNITED STATES OFFICE HAMMER W'ITH ADJUSTABLE FULCRUM Application filed January 25, 1828.

This invention relates to a hammer, and more specifically to one especially adapted for pulling nails, and has among its objects:

To devise a claw hammer having an adustable fulcrum To invent a hammer especially adapted to pulling nails of considerable length;

To provide a hammer whereof the head may be moved out from the surface against which pull is being exerted;

To produce a hammer like that described above which shall be cheap to manufacture and durable and trouble free in use.

In the drawing:

Fig. 1 is a side elevation of my invention with. parts broken away to show the interior construction Fig. 2 is an end elevation thereof with the end of the shank cut away on line 22, Fig. 1, to make this aspect of the head completely visible;

When using a claw hammer to extract nails from boards more or less ditliculty is encountered if the nails be long, as it is necessary jto place a block under the heel of the hammer to raise the tool up so the pull may beapplied to the head of the nail; if a block be not used the nail is bent and so binds against the wood, making extremely diflicult to withdraw. It is to overcome all the inconveniences incident to such operations that I have made my invention.

My device comprises a head 3 of any shape employed in the claw-hammers in use and includes claws 4. Instead of an all wood handle I employ one having a metal shank 5 secured in a wooden grip portion 6 by forming in said wood a recess of a size and shape adapted to fit closely the shank and passing rivets through both members. That edge of shank 5 nearest claws 4 has a shallow channel 7, arcuate in cross section, formed in it. The free end of said shank may be formed with a corrugated or otherwise roughoned surface 8 and is swaged over to form an enlargement 9 to prevent complete removal of said head. from the shank; or said enlargement may be a separate plate suitably fixed to said shank.

Formed in the head is a recess 10 which Serial No. 249,345.

opens laterally into eye 11; said recess is tapered, being deeper in the part 12 than at 18, though the width remains the same throughout. Within said recess is a hardened steel ball 14, whereof the diameter is less than the depth of recess 10 at part 12 but greater than at 13. A. relatively heavy spring 24 pushes ball 14 toward the small end of said recess into contact with up-turned end of 15 of slide 16; a lighter spring 17 which seats on a short stud 18 fixed to-end 15 keeps the said end of said slide snugly against said ball. A second upturned end 28 is formed on slide 16 to be engaged by the thumb or finger of the user of the hammer when it is desired to move the head 3 toward end 9 of the shank 5. A plate 19 closes the outer end of recess 10; as here shown a bevelled edge 20 of said plate fits in an undercut slot in said headand the opposite edge is fixed by means of screws 21, though obviously any other means for accomplishing this may be used; a small stud 22 on said plate "forms a means to keep one end of spring 24 in place.

It is obvious that the construction set forth permits head 8 to move readily along shank 5 toward the handle, but when it tends to move in the opposite direction the diminished height of recess 10' causes ball 14 to wedge between the wall of said recess and shank 5 and prevents the head sliding that way.

The method of using my hammer is as follows:

The claws 4 having been wedged under the head of the nail, with the shank of the nail between said claws, the hammer is used to pull the nail as far as,it may be done easily in the usual way; then, with the claws still gripping the nail, the hammer is rocked toward the claws, using the nail as a pivot,- while pushing down on the handle; applying downwardly directed pressure to the handle releases the lock between shank 5 and head 3 formed by ball 14 and permits said shank to slide through said head. When the hammer is now rocked away from claws 4 the projecting portion of shank 5 below head 3 will be long enough to lift said head up from the surface at which the pull began to the height of the nail head, and the tendency of head 3 to slip down on shank 5 cannot result in movement because of the wedging of ball 14 between the shank 5 and the wall of tapered recess 10.

Spring 24 insures that ball 14 will at all times be far enough in said recess to contact both shank 5 and head 3 and hence will wedge between the two at the least movement of the two at the least movement of said head toward the free end of said shank. As shank 5 has a tendency to fulcrum about the edge 25 the ball 14 is more firmly gripped, and so positively prevents slippage of head 3 during the pulling; that is, if ball 14 were not present, handle 5 would move on edge 25 as a fulcrum, but as the said ball is present, such fulcruming movement is prevented and said ball is tightly gripped.

The function of slide 16 is to move ball 14 out of the locking position, against the pressure of spring 24, when it is desired to move head :3 toward the free .end of shank 5; the head can 'bemoved out without using said slide, but there is a tendency for the ball '14 to grabland prevent smooth move ment ofthe head. It is obvious that my hammer is as good for driving nails as the ordinary hammer, and in addition is much better for pulling nails.

I claim:

1. A hammer, comprising a head, an eye in said head, a handle shank slidable in said eye, and automatically acting locking means between said shank and a surface formed on said head.

2. A hammer, comprising a head, an eye in said head, a shank slidable in said eye, a recess formed in said head and opening into said eye, and a freely movable element disposedin said recess in contact with said head and said shank.

3. A hammer, comprising a head, an eye in said head, a shank slidable in said eye, a

tapered recess formed in said head and openlng lnto said eye, a movable element in said recess, and spring disposed to force said element toward the shallow end of said recess.

4. Ahammer, comprising a head, an eye in said head, a shank slidable in said eye, a tapered recess formed insa'i'd head and opening into said eye, a shallow channel formed in said shank facingsa-id recess, a ball disposed in said recess, means toforce said ball toward the small end of said recess, and means operable to move said ball toward the large end of said recess.

5. A hammer, comprising a head, an eye in said head, a tapered recess in said head opening laterally into said eye and one end thereof opening on a face of said head, a plate over the open end of said recess, a ball in said recess, a spring seated at one end JOHN w. oARLsoN.