Tools – Hammer
Reexamination Certificate
1999-08-10
2001-04-24
Smith, James G. (Department: 3723)
Tools
Hammer
C081S177100, C030S529000
Reexamination Certificate
active
06220120
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to hand held pounding instruments such as hammers and mallets.
2. Description of the Prior Art
Using a hand held pounding instrument such as a hammer or a mallet to drive a spiked object such as a nail or a tack into a surface is a precise and often arduous task. In order to optimize the work accomplished with each stroke of the pounding instrument, it is imperative that the pounding instrument deliver the maximum amount of force to the spiked object with each strike and the pounding instrument must deliver this force at the optimal angle so as to drive the spiked object straight into the surface. The result of an inaccurate hit on the nail or other spiked object will typically result in the need to perform additional strikes to complete the task or may even result in the damaging of the nail or other spiked object requiring the user to remove the nail and start over with a new nail.
There are a variety of hand held pounding instruments in the prior art which can be used to drive a spiked object through a surface. These pounding instruments typically consist of a handle and a pounding head. The pounding head has a pounding surface, and both the pounding surface and the pounding head are typically aligned to the handle so that a reference plane running through the axial center of the pounding surface, bisecting the pounding head, will also serve to bisect the handle through the axial center of the handle along its front and rear portion.
One of the drawbacks to the prior art is that the pounding head and the pounding surface will typically not align with the forearm when the pounding instrument is grasped by the hand in a normal fashion. Due to the skeletal structure of the hand, grasping a typical handle for a pounding instrument in a normal fashion, with (
FIGS. 5 and 6
) the fingers, other than the thumb, resting across the front portion of the handle, will turn the handle anywhere from 6.5° to 9.5° from a line across the center of the forearm defined by the radius (FIGS.
3
and
4
). This in turn results in an offset angle of 6.5° to 9.5° between the pounding head and a line across the center of the forearm defined by the radius.
Due to this offset between the forearm and the pounding surface, the prior art pounding instruments requires substantial movement by the wrist in order to generate an accurate hit on a spiked object such as a nail or a tack. Typically, when an accurate hit is required on a spiked object, the user generates a stroke of the pounding instrument by the controlled movement of the wrist with little help from the forearm.
The bones which comprise the wrist are small and so are the muscles which attach to the bones. As a result, the wrist does not have the leverage to generate as much power as the longer bones in the arm like the radius, and since the muscles in the wrist are smaller they fatigue significantly quicker than the longer muscles which are attached to the longer bones in the arm. Subsequently, in order to generate greater power in a single stroke of a pounding instrument, and in order to minimize fatigue, the forearm must be incorporated in the pounding stroke, and movement of the wrist must be minimized.
Consequently, significant improvement in the design of a pounding instrument can be achieved by designing a pounding instrument which aligns the pounding head and the pounding surface to the forearm, specifically the radius bone. By doing so, the pounding stroke can be changed in order to provide greater accuracy and power. If the pounding head is aligned to the forearm, the wrist can remain locked while the forearm is used to drive the pounding instrument.
Accordingly, there is a need for a pounding instrument with a pounding head and pounding surface that is ergonomically aligned with the forearm in order to minimize the involvement of the wrist in a pounding stroke and to maximize the involvement of the forearm.
The present invention is an ergonomically designed pounding instrument having a built in offset which allows the pounding head and the pounding surface to align with the forearm when gripped in a normal fashion.
As will be described in greater detail hereinafter, the present invention solves the aforementioned and employs a number of novel features that render it highly advantageous over the prior art.
SUMMARY OF THE INVENTION
Accordingly it is an object of this invention to provide an ergonomically designed pounding instrument having a built in offset which allows the pounding head and the pounding surface to align with the forearm when gripped in a normal fashion, allowing the user to maximize the use of the forearm in the pounding stroke while minimizing the movement of the the wrist.
To achieve these objectives, and in accordance with the purposes of the present invention the following ergonomically designed pounding instrument is presented.
A pounding head is mounted onto a handle at an offset with respect to the handle in order to align the pounding head with the forearm. In the preferred embodiment, this offset is defined by an angle &bgr; created between a first reference plane extending through the axial center of the pounding head and bisecting the pounding head and a second reference plane extending through the axial center of the handle, bisecting the handle along its front and rear portion.
In order to align the pounding head and the pounding surface to the forearm, the angle should be greater than or equal to 6.5° and less than or equal to 9.5°. In the preferred embodiment, the angle &bgr; is 8°. Due to the skeletal structure of the hand, grasping a typical handle for a pounding instrument in a normal fashion, with the (
FIGS. 5 and 6
) fingers, other than the thumb, resting across the front portion of the handle, will turn the handle an angle &thgr; from a line across the center of the forearm defined by the radius, &thgr; being anywhere from 6.5° to 9.5°. By offsetting the pounding head by the angle &bgr;, the misalignment between the pounding surface and the forearm resulting from the normal grasping of the handle is significantly reduced or eliminated.
Once the pounding head and the pounding surface is aligned to the forearm. The pounding stroke can be changed to incorporate the forearm and minimize any movement of the wrist. The resulting pounding stroke will involve grasping the pounding instrument in a normal fashion, locking the wrist, and radially moving the forearm about the elbow. When viewed from the side, the forearm moves radially in a counterclockwise fashion to deliver a blow and moves radially in a clockwise fashion to recoil. The length of this new pounding stroke builds greater acceleration in the pounding head and the pounding surface, resulting in greater power being delivered with each blow. Furthermore, since there is no wrist manipulation involved in this new pounding stroke, greater accuracy can also be achieved with each stroke.
Other objects, features, and advantages of the invention will become more readily apparent upon reference to the following description when taken in conjunction with the accompanying drawings.
REFERENCES:
patent: D. 273759 (1984-05-01), Drori
patent: 1142946 (1915-06-01), Ellis
patent: 2656225 (1953-10-01), Saylor
patent: 3877826 (1975-04-01), Shepherd, Jr. et al.
patent: 4363344 (1982-12-01), Pollak
patent: 4399978 (1983-08-01), Moore
patent: 4805494 (1989-02-01), Santoro
patent: 5062324 (1991-11-01), Saviano
patent: 5125130 (1992-06-01), Stanish
patent: 5161293 (1992-11-01), Ebbert
patent: 5280738 (1994-01-01), Liou
patent: 5588343 (1996-12-01), Rust et al.
Meroni & Meroni P.C.
Meroni, Jr. Charles F.
Ojini Anthony
Smith James G.
LandOfFree
Ergonomic tool does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Ergonomic tool, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Ergonomic tool will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2462977