US3303863A - Momentum hammer with a handle carried slidable weight - Google Patents

Description

Feb. 14, 1967 w. M. TITCHNELL 3,303,863

MOMENTUM HAMMER WITH A HANDLE CARRIED SLIDABLE WEIGHT Filed July 9, 1965 INVENTOR.

WILLIAM M. T/TCHNELL BY MAHoyEY, MILLER a RAMBO A TORN E YS United States Patent 3,303,863 MOMENTUM HAMMER WITH A HANDLE CARREED SLIDABLE WEIGHT William M. Titchnell, R0. Box 27066, Columbus, Ohio 43277 Filed July 9, 1965, Ser. No. 470,817 6 Claims. (Cl. 145-29) My invention relates to a momentum hammer. It rel-ates to a lightweight, hand-type hammer provided with means for automatically increasing the momentum during the swinging of the hammer and just prior to striking a blow thereby producing an increased impact with less strain, fatigue and shock on the hand and arm of the user.

With the ordinary hammer or similar hand tool, the center of mass is at or very near the hammer head, thus creating a large moment to be restrained by the hand and arm muscles except during the actual striking of the blow with the hammer. The hammer of the present invention has its center of mass considerably farther down the handle away from the hammer head, as compared with the usual hammer, during most of the swing toward impact, giving a more comfortable feeling in the hand and arms of the user, but is provided with means for automatically increasing the mass of the head as it nears impact. The increase in mass at the head provides a greatly increased moment to thereby greatly increase the striking force at impact. It is preferred that the means for increasing the mass of the hammer head at impact be a shiftable weight, for example, a ball, which is mounted in a guide passage extending along the handle from a point adjacent its end to a location within the hammer head. Means is provided at the end of the handle for normally restraining movement of the weight until sufficient centrifugal force is developed by the swing of the hammer toward impact to move the weight into the hammer head. This will result in an increase in mass .in the hammer head and greater impact at the time it is needed but a decrease in weight and mass at other times to thereby decrease strain and resulting fatigue on the user.

In the accompanying drawing, I have illustrated my invention embodied in a hammer of the type used for driving nails and similar work but is to be understood that the same principles may be incorporated in any hand tool or device which has a handle and a head and which is to be swung by the handle during use. For example, the invention may be incorporated in other items, such as mallets, axes, golf clubs, etc.

In the drawing:

FIGURE 1 is a longitudinal sectional view through the hammer.

FIGURE 1a is a similar sectional view of the head of the hammer showing the moment-increasing ball located in the head.

FIGURE 2 is a head-end elevational view taken from the position indicated at line 2-2 of FIGURE 1.

FIGURE 3 is an enlarged transverse sectional view taken through the hammer handle.

\Vit'h reference to the drawing, as indicated above, in the example shown, the tool is a hammer which comprises mainly a handle having a head 11. The head and handle are shown as being integral but may be formed separately and suitably connected. Also, the specific shape of head and handle is not important to the invention and can be varied.

The handle 10 is shown in the form of a hollow tube which has its outer surface of a contour to properly fit the hand and has a guide passage 12 of circular cross section extending its full length. In forming the passage 12, it may be formed with both ends open to facilitate its formation, with the ends later closed by means indicated and which will be described. The head 11 may be provided with a replaceable impact knob 13 which may be mounted on the head itself by a screw and socket arrangement as indicated at 14.

Within the passage 12, for automatic movement therealong, I have provided a shiftable Weight 15. This weight is shown as a ball which is magnetic for a purpose which will -be apparent later and is of steel or other magnetic material. The ball is of a diameter just slightly less than the internal diameter of the passage 12 so that it will fit snugly therein. The end of the passage 12, at the end of the handle, is closed by a removable permanent magnet 16 of disc-like form which is screwed into a threaded socket at the extremity of the passage 12. When the ball 15 moves or rolls to the end of the handle 10 in the passage 12, it will contact the magnet 16 and be retained in that position until the magnetic force is overcome. To aid in retaining it in that position, the side of the passage 12 is provided with a hemispherical slot or socket 17 extending radially outwardly into the inner surface thereof. This socket is of greater diameter than the diameter of the ball 15 and will receive the ball when the ball moves to the end of the handle. It will be noted that the axis of the socket 17 is in a plane common with the axis of the passage 12 and the impact member 13 and extends radially in the direction of the member 13.

The passage 12, as indicated, extends into the head 11 and this end of the passage is closed by a removable cap 18 of disc-like form which is screwed into the threaded outer end of a socket 19 -at the end of the passage. A disc 20 is mounted for axial movement in the socket 19 and is normally biased inwardly against an annular stop shoulder 21 by means of a compression spring 22 disposed between the disc members 18 and 20. Immediately axially inwardly of the stop shoulder 2-1 preferably there is provided an annular enlargement 23 which forms an annular chamber that communicates with the passage 12. The wall surfaces of this chamber is preferably curved spherically substantially complemental to the surface curvature of the ball 15. The inwardly springpressed disc 20 provides a ball movement cushioning and return plunger arrangement which will function in a manner to be described below. If desired, the passage 12 and connected chamber 23 may be filled with a viscous fluid which will dampen movement of the ball 15 and dampen out shock or a dashpot (not shown) may 'be operatively connected in series with the spring 22.

Assuming the hammer handle 10 is grapsed by the user, and the handle is vertical or is tilted rearwardly and downwardly toward the user with the end of the hammer lower than the head 11, the weight ball 15 will be in the end of the handle in the socket 17 at the position indicated by full lines in FIGURE 1. In swinging the hammer head 11 toward the article to be struck, the ball 15 will stay in the indicated position, until sufiicient centrifugal force is developed to overcome the magnetic retaining force and to c ause the ball to ride up out of the socket 17. The ball will then quickly move through the passage 12 until it strikes the contact button 20 which will cushion its impact and as the contact member 13 moves toward impact, the ball will move .into the side of the annular chamber 23 away from that member, as indicated in FIGURE 1a. This will increase the mass of the hammer head just prior to and at the time of impact to thereby give a more effective blow. The spring 22 will cushion the movement of the ball as it reaches the head and will be compressed to some extent at this time by contact of the ball 15 with the disc 20. At impact. the ball 15 will tend to quickly move to the opposite side of the chamber 23 and exert -a dampening effect on the rebound of the hammer head 11 resulting from impact.

a As the hammer head rises after the blow, the tendency of the ball to roll from the chamber 23 into the main part of the passage 12 will be aided by the biasing effect of the spring 22. The ball will continue to move along the guide passage 12, as the head of the hammer is raised to a greater extent, and will move downwardly until it reaches the end of the handle and is retained in that position by contact with the magnet 16.

With this arrangement, the momentum-increasing weight does not move into the head 11 of the hammer until sufiicient centrifugal force is developed, during the swing toward impact, to overcome the weight-retaining force of the magnet 16. The weight, in the form of the steel ball 15, releases from the permanent magnet 16 due to the increase of the g force to overcome the force of the magnet which results from the swinging of the hammer toward impact. Upon completion of the swing, the ball is in the chamber 23 at the instant of impact, thus giving the hammer head its full mass to simulate the tangential force of a conventionally constructed hammer with a heavier head. Upon impact, the movement of the ball in the chamber 23, toward the impact side, cushions the rebound of the hammer head and the spring-biased ball contacting disc tends to exert a force on the ball which will deflect it in the passage 12 toward the magnet 16. At the upper return portion of the hammer swing, the ball 15 is back at the magnet 16 and the process is repeated with each subsequent swing. The hemispherical socket 17 is utilized to keep the steel ball 15 from moving forward during aiming or back swings of the handle and the ball will be positioned therein each time it moves into the rear end of the handle in contact with the magnet 16, On back swings, g forces keep the ball in the socket and keep centrifugal force from forcing the ball toward the head.

As previously indicated, my invention is not limited to a hammer but may be incorporated in any device comprising an impact head and a connected handle for swinging it through a working arc, with the movable weight being so carried by the handle that will move into the head automatically as it is swung towards impact to thereby increase the weight and inertia of the head at impact.

According to the provisions of the patent statutes, the principles of this invention have been explained and have been illustrated and described in what is now considered to represent the best embodiment. However, it .is to be understood, that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described.

Having thus described this invention, what is claimed 1. An i mpa ctapplying device comprising an impact head, a handle connected to the head for swinging it into an impact position, a weight mounted on the handle for movement from a position along the handle remote from the head to a position at the head to increase the weight of the head as it is swung by the handle toward impact, and means for retaining the weight in said remote position until a predetermined centrifugal force is developed during swinging of the head toward impact.

2. An impact-applying device comprising an impact head, a handle connected to the head for swinging it into an impact position, said handle being provided with a guide passage extending therealong from a remote position to a position in the head, a weight mounted in said guide passage for movement between said remote position and the head, and means adjacent said remote position of the passage for exerting a retaining force on said weight which can be overcome by centrifugal force developed by swinging of the head with said handle toward impact.

3. An impact-applying device comprising an impact head, a handle connected to the head and extending therefrom to a remote end for swinging it to and from impact position, said handle being provided with a guide passage communicating with a chamber in said head and extending along the handle to the remote end of the handle, a ball weight of magnetic material mounted in said passage for movement therealong and into and out of said chamber, and a magnet at the remote end of the handle for normally retaining said ball at said remote end of handle.

4. A device according to claim 3 in which said passage has a ball-receiving socket in the wall thereof adjacent said remote end of the handle.

5. A device according to claim 3 in which said chamber in said head is a continuation of said passage and is provided with a spring-biased plunger with which said ball will engage when it moves into said head.

6. A device according to claim 3 including means acting on the ball in said chamber for deflecting it in said passage toward the magnet at the remote end of the handle after impact.

References Cited by the Examiner UNITED STATES PATENTS 7/ 1952 K-ahlen. 8/1961 Yearley.

Claims (1)

1. AN IMPACT-APPLYING DEVICE COMPRISING AN IMPACT HEAD, A HANDLE CONNECTED TO THE HEAD FOR SWINGING IT INTO AN IMPACT POSITION, A WEIGHT MOUNTED ON THE HANDLE FOR MOVEMENT FROM A POSITION ALONG THE HANDLE REMOTE FROM THE HEAD TO A POSITION AT THE HEAD TO INCREASE THE WEIGHT OF THE HEAD AS IT IS SWUNG BY THE HANDLE TOWARD IMPACT, AND MEANS FOR RETAINING THE WEIGHT IN SAID REMOTE POSITION UNTIL A PREDETERMINED CENTRIFUGAL FORCE IS DEVELOPED DURING SWINGING OF THE HEAD TOWARD IMPACT.

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