Implements or apparatus for applying pushing or pulling force – Nail extractor type – Hammer and anvil
Reexamination Certificate
2001-08-09
2003-10-07
Wilson, Lee D. (Department: 3723)
Implements or apparatus for applying pushing or pulling force
Nail extractor type
Hammer and anvil
C254S02600E, C254S021000, C254S018000
Reexamination Certificate
active
06629684
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to nail pulling devices and more specifically it relates to a combination prying and nail pulling device that provides a user with the ability to both pull nails and pry materials from surfaces, particularly angled surfaces.
BACKGROUND OF THE INVENTION
In the field of construction, workers often pry materials from surfaces such as roofing tiles affixed to a roof, or boards affixed to a wall. Using traditional tools, the nails are removed from the materials with a claw hammer or similar device, and a crowbar or other prying tool is used to pry the materials from the surface. The surfaces may be flat or curved, and may further be angled. With respect to angled surfaces such as roofs or slanted walls, prying nails and other materials affixed to the angled surface can be difficult since traditional prying tools tend to be generally straight or with very short hooked pulling heads. Such straight or hooked pulling heads do not provide sufficient leverage against the angled surface, and pulling materials is difficult and slow, requiring repeated pullings to remove materials with a large surface area. In addition, when dealing with such large materials (such as roofing tiles), the short curved surface is generally too short in length to provide an efficient detachment of the materials.
Nail pulling and prying devices are common in the prior art. One common category of such devices are crowbar-type lever devices, which comprise a pulling head that is inserted under the material to be removed and a long shank, where the force is applied at the end of the shank opposite the head. In many crowbar type devices the head is often hooked, resulting in a fulcrum (or pivot point) relatively close to the head. In addition, the hooked head is generally relatively short and sharply hooked, sometimes with an angle between the u-shaped portion of the hook and the shank near or over 90°. This relatively strong curvature combined with the generally short hook limits the distance to which the hook can be inserted under the material to be pried. If the material is long or large, this shape requires the user to make repeated and incremental pullings to remove long or large materials, particularly large sheeted materials such as roofing tiles. Where the head is not hooked but is merely angled, the leverage to be applied is limited by the range of motion the use can make before encountering the surface, i.e., the wall or roof. In these cases, the nail pulling operation is inefficient since the upward motion of the material to be pulled is very limited, and may not exceed the length of the nail. Lastly, many related prior art devices cause damage to the surface from which the materials are pulled. Some of these devices have two pry blades at opposite ends, with the opposing blade extending transversely.
Also included in this category is the common claw-tooth hammer, which has a relatively short shank compared to a crowbar. These devices suffer from the drawback of having a short hook, but also from having a deep curved claw. In such devices, the claw contains the fulcrum, and the curvature of the claw provides the leverage, with greater leverage obtained from more curve being used for rotation. When using such a device to remove nails, for instance, the claw must be inserted such that the nail shank is trapped between the two teeth of the claw. As most nails have a very narrow shank, this means that most of the curvature of the claw used for pulling the nail is wasted, as the nail shank is generally trapped only when inserted deeply into the claw, leaving relatively little curvature left to rotate and provide leverage for extracting the nail.
Thus, using prior art devices having a hooked curve or a very small or no curve, there is insufficient lift area to effectively separate large surface area materials from surfaces. In such cases, many small pulling movements must be taken, rather than one or two large pulling actions that loosen much of the material in one movement. The user will appreciate that small pulling movements are inefficient and can cause undue stress on the body.
It would therefore be an advantage to have an improved nail pulling and prying device that provides greater leverage than prior art devices when removing materials from angled surfaces, or when removing large materials. It would also be an advantage to have a combination device, which combines the functionality of a crowbar with the functionality of a nail puller in a single device that is effective for pulling nails and other materials from angled surfaces.
SUMMARY OF THE INVENTION
A primary object of the invention is to provide an improved combination tool for nail pulling and prying objects with a large surface area in a single device.
Another object of the present invention is to provide an improved device for prying materials and nails from a slanted surface, which device provides more leverage on slanted surfaces than commercially available prior art devices.
A further object is to provide an improved prying device for slanted surfaces wherein the prying portion of the device is configured to enable the prying of material having a large surface area from a slanted surface more easily than compared to conventional prying tools with a hooked blade or blade with little or no curvature.
In accordance with the principles of the present invention, there is provided a device suitable for pulling nails and other materials from surfaces, most particularly angled surfaces. The device includes a blade end, a shank and a grip end, wherein the blade end further comprises a curved lever, and the grip end is transversely situated opposite the blade end, with the shank interposed between the grip end and the blade end.
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4 Pages from website WWW.ESTING.COM regarding various pry bars and pullers, printed on Jan. 18, 2002.
Weir Timothy J.
Youngren Robert Harold
Estwing Manufacturing Company
Gardner Carton & Douglas LLC
Wilson Lee D.
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