US3150858A

US3150858A - Nail extractor

Info

Publication number: US3150858A
Application number: US241859A
Authority: US
Inventors: Vernon J David
Original assignee: Individual
Current assignee: Individual
Priority date: 1962-12-03
Filing date: 1962-12-03
Publication date: 1964-09-29
Anticipated expiration: 1981-09-29

Description

v. J. DAVID NAIL EXTRACTOR Sept. 29, 1964 Filed Dec. 3, 1962 INVENTOR VERNON J. 04 W0 ATTORNEY United States Patent 3,150,858 NAEL EXTRACTGR Vernon J. David, Durham, Karts. Filed Dec. 3, 1962, Ser. No. 241,859 5 Claims. (Qt. 25426) This invention relates to a nail pulling device, and consists more particularly in new and useful improvements in a nail extractor, preferably for use in association with the head of a hammer or similar hand tool, and which may be formed as an integral part of the hammer head or as an attachment to be aflixed thereto.

Conventional hammers have long been provided with heads equipped with nail pulling claws at the longitudinal extremity opposite the striking end, and some individuals have undertaken to improve upon this arrangement by applying auxiliary nail pulling notches which are radially disposed with respect to the longitudinal axis of the hammer head. However, the conventional claw hammer, as well as these efforts to improve same, have had certain shortcomings and limitations. It can readily be understood that the conventional claw hammer particularly in the straight-claw configuration, is severely limited in nail pulling mechanical advantage, and, in addition, badly mars the wood when the nail pulling cycle is continued to and beyond the position where the striking portion of the head becomes impressed into the wood. Lack of mechanical advantage often results in hammer handle or hammer head breakage and requires undue effort in large nail removal operations. In addition, the method of gripping the nail is often inadequate, resulting in nail head separation and subsequent difiiculty in nail removal. Basically, they employ an external fulcrum and pivot point. The fulcrum and pivot locations are substantially the same. This severely limits mechanical advantage and smooth operation, as well as providing inadequate nailgripping action. In addition, this results in the undesirable condition where a large nail is held at a greater distance from the fulcrum and pivot point than a smaller nail.

It is generally understood that claw hammer configuration varies greatly depending on job requirements. Design may range from extreme curvature of the claws to straight claw. Each design has its specific advantages. Curved claw types are best suited for nail pulling use but are greatly limited in use for chipping, chopping, prying and sometimes have difficulties of proper balance and feel. Straight claw configuration has none of these disadvantages, but has the inherent shortcoming of limited mechanical advantage in nail pulling uses, resulting in hammer handle and hammer head breakage. Many compromise designs are offered for use, but continued development of greater strength hammer handles and hammer heads indicate that a proper solution to this problem does not lie entirely in this line of improvement. In addition, it is well known in construction trades that a Wood or similar weight and feel hammer handle has proven most desirable from an efiiciency, ease of operation, and general desirability standpoint. In view of this and other obvious reasons that become apparent through examination and study of this patent application, it is the object of this invention to provide an improved nail removal means featuring new principles and structural improvements resulting in more favorable mechanical advantage; better nail size, fulcrum-pivot point distance relationship; greater structural strength; better nail gripping action; increased circumference effect; and other related advantages.

Basically, the new principles of operation feature a rolling, sliding, rotating, extraction action in which the fulcrum point and pivot point may be in ditlerent locations during various phases of the nail pulling cycle. For example, the pivot point may be located internally of the nail pulling means body as a direct result of the rolling, sliding, rotating, extraction action.

Structural improvement features are inherently integrated with the principles of operation. In the nail ex "traction process, the nail removal means provides one area for the removal action, while the surface from which the nail is being removed provides the other bearing location. The nail serves to determine and limit the location of the extraction process. The ratio of rotation, sliding or rolling may be controlled in several different ways, such as varying the dimensions of the nail removal means to supply more or less bearing area depending on the amount of friction desired. Friction means may be pro vided on the nail removal means if additional rolling action is desired. For example, corrugated, roughened, or a gear-tooth effect may be provided to supply more traction. Also, the shape of the nail removal means may be varied to regulate rotation, rolling, or sliding during the various stages of the extraction cycle. It should be understood that in this, as in most machines, friction is usually kept to a minimum to promote greater efficiency.

Nail size, fulcrum-pivot point, distance relationship is an inherent product of the new principles of this design. A larger size nail is held a greater distance from the fulcrum and pivot point, in the conventional claw hammer. My invention, utilizing the new principles of rolling, sliding, rotating extraction action, together with properly curved, short radius, closely coupled and otherwise correctly shaped nail removal means provides a nail size fulcrum, pivot point relationship whereby nail size has little effect on fulcrum-pivot point distance. For example, if nail grasping'claws did not protrude at all and were curved to conform to the cylindrical shape of the extraction means, large and small nail fulcrum and pivot distances would be very nearly alike. The remaining differences would be that caused by the difierent nail shank diameter size as the shank is rolled around the hammer head in the extraction process.

Circumference effect is an integral part of this invention and contributes to improved nail gripping action by providing a proper pulling angle whereby the nail shank is securely directed into the wedge shaped claws. Circumference effect also provides a greater pulling distance than if the nail was'allowed to merely conform to the diameter distance as is common with conventional nail extraction tools.

With the above and other objects in view which will appear as the description proceeds, the invention consists in the novel features herein set forth, illustrated in the accompanying drawings, and more particularly pointed out in the appended claims.

Referring to the drawings in which numerals of like character designate similar parts throughout the several views:

FIG. 1 is a perspective view of a conventional claw hammer head with the pulling device of the present invention applied to its striking end;

PEG. 2 is a plan view of the underside of the hammer head shown in FIG. 1 with the hammer handle in crosssection;

PEG. 3 is an end View of the hammer head taken from its striking end;

FIG. 4 is a fragmentary perspective view of a conventional hammer head showing the nail pulling device of the present invention in the form of a separate attachment;

FIG. 5 is a view from the underside of the hammer head showing the nail pulling attachment welded to the striking end of the hammer head; and

tion action.

hammer head by any suitable means, such as by welding,

oneness FIGS. 6-9 are transverse sectional views through the striking end of a hammer head, diagrammatically illustrating the sequence of a nail pulling operation from start to finish.

In the drawings, referring first to FIGS. 13, 1!) rep resents a hammer head equipped with a conventional claw end 11 and right angular disposed handle 12. In the preferred form of the invention, the nail pulling device is formed as an integral part of the striking end 13 of the hammer head 10, and comprises a cylindrical base or body 14 co-extensive with the striking end of the hammer. Opposite sides of the periphery of body 14 are provided with integral pairs of properly shaped extractor lugs 15 which project from the underside of the striking end 13 with their respective outer or bearing faces 16 lying tangentially with respect to the periphery of the body 14. The bearing faces of the co-acting lugs of each pair are separated by V-shaped slots 17, the edges of which converge in the periphery of the body 14, and each slot opens into an enlarged, open-ended nail head cavity 18, formed jointly inrespective pairs of lugs. As seen in the drawings, these cavities 18 are substantially cone-shaped with their walls diverging from the base 14-. The end surfaces 19 of the lugs adjacent the cavity openings are preferably inclined to provide relatively sharp, complementary nail head engaging teeth 2%.

As bests'een in FIG. 1, the diameter of the base 14 is enlarged so that its periphery is raised or projects radially beyond the adjacent portions of the hammer head it) so that said periphery and the tangential bearing faces 16 of the lugs 15 form a continuous bearing surface from the gripping teeth 29 of one pair of lugs to the gripping teeth 20 of the opposite pair of lugs. Thus, the entire extracting device is capable of an unrestricted rotating, sliding, rolling extraction action against the bearing surface from which the nail is being removed, and without the danger of adjacent sharp edges of the hammer head .marring the surface. The sequence of this extraction action will be described later on.

As-previously stated, the nail pulling device of the present invention may be embodied as an integral part of the striking end of the hammer head in the manner described, or it may be formed as a separate attachment for application to a conventional hammer head. One form of an attachment embodiment is illustrated in FIGS. 4 and 5 where it will be seen that a substantially arcuate body member 21 terminates at its opposite extremities in coacting pairs of extraction lugs 23, the outer or bearing faces 24 of which are extended tangentially of the periphery of the body 21 in the same manner as the bearing surfaces 16 of the lugs 15 previously described. The lugs of respective pairs are separated by V-shaped slots 25, the projecting ends of each pair of rugs forming coacting nail head gripping teeth 26 as in the FIG. 1 embodiment. Here, however, the lugs are not provided with the enlarged nail head cavities. The thickness of the attachment 21 would be such that when applied to the periphery 22 of the hammer head, the arcuate bearing surface of the attachment 21 is radially offset beyond the adjacent portions of the hammer head so as to provide a completely independent and unrestricted rolling, rotating, sliding extrac- The attachment may be secured to the as at 27 as shown in FIG. 5.

The sequence of operation as shown more or less diagrammatically in FIGS. 6-9 is representative of the action of both the integral embodiment of the invention shown in FIG. 1 and the attachment form shown in FIG. 4. In FIG. 6, the beveled teeth Ztl of the lugs 23 have initially engaged beneath the head of the nail and the line of leverage 29 which represents the hammer handleextends relatively parallel with the surface from which the nail is being removed, horizontally intersecting the axis located in the general area designated as of the striking end 13 of the hammer. In P16. 7, the hamrncr head has been rotated in counterclockwise direction, starting the extraction of the nail, and the continued rotation of the hammer head as shown in FIG. 8 produces a rolling, rotating, sliding extraction action. Nail gripping action is improved through the nail shank being caused to embrace the periphery of the

body

14 or 21 providing increased wedge action into the teeth 20 of the lugs 23 because of better gripping'angle. FIG. 9 shows the extractor after having been rotated substantially 180 and with the nail end Wrapped practically around the periphery of the body 21.

Throughout this sequence of operation, it will be noted that the rolling, rotating sliding action of the extractor body 21 may cause the fulcrum point and pivot point or axis to be in different locations during various phases of the nail pulling cycle. For example, the pivot point or axis may be located internally of the nail pulling means

body

14 or 21 while the fulcrum point is located externally. The nail N serves to determine the location of the extraction process. The periphery of bearing surface of the body serves as a fulcrum against the bearing surface from which the nail is being extracted.

It will be apparent that with the present invention, a greatly reduced force is required to effect nail extractions and, consequently, handle breakage is reduced to a minimum. Furthermore, it also follows that because of the reduced stresses resulting from this invention, the handle length may be increased without danger of breakage.

Another advantage of this arrangement lies in the fact that as distinguished from conventional nail pulling devices which have a limitation of approximately rotation about an axis, the nail pulling arc of this invention is inherently greater and ordinarily provides a nail pulling arc of about or in some instances, such, for example, as pulling nails on a narrow ledge, the handle may be rotated 360 or more degrees.

It will thus be apparent that the present invention provides an improved mechanical advantage, greater ei'h ciency, more effective operation, and greatly improves the standard of performance of tools of this nature.

From the foregoing, it is believed that the invention may be readily understood by those skilled in the art without further description, it being borne in mind that numerous changes may be made in the details disclosed without departing from the spirit of the invention as set forth in the following claims.

I claim:

1. In a hand tool having a head with a nail striking element at one end thereof and a handle extending at substantially right angles to the longitudinal axis of said striking element; a nail extracting device mounted on said striking element and comprising a thin body portion having a susbtantially cylindrical bearing surface concentric with respect to said longitudinal axis of said striking element, said bearing surface of the said body portion being integral with said striking element, at least one side of said body portion having a pair of coaching nail engaging lugs pro'ecting therefrom in a line substantially parallel with said handle, said lugs having bearing faces which are tangentially disposed with respect to said bearing surface of said body portion at their point of intersection with said body portion so as to form a continuation of said bearing surface, whereby upon rotation of said body portion about said longitudinal axis of said striking element in either direction with said bearing surface embracing the surface from which a nail is to be extracted and with said lugs engaging the nail head, said longitudinal axls remains substantially fixed with relation to said nail, and said bearing surface acts as a rotating, sliding,

rolling fulcrum.

2. A device as claimed in claim 1, wherein opposite sides of said body are each provided with a pair of coacting nail engaging lugs.

3. A device as claimed in claim 1, wherein the lugs of said pair are separated by a substantially V shaped slot,

5 the edges of which converge at the periphery of said body portion, said slot opening into an enlarged cone sliaped nail in ad receiving cavity formed in opposed surfaces of adjacent lugs.

4. A device as claimed in claim 1, wherein the pcripheral surface of said body is radially outwardly oliset With respect to the adjacent area of said tool head.

5. A nail extracting attachment for a hammer head or the like, provided with a right angulariy projecting handle, said attachment comprising a semicircular metal body having an inner diameter coinciding with the oute diameter of a portion of said head and attachable thereto in concentric relation to the longitudinal axis of said head, said body being of sufficient thickness to dispose its outer 6 periphery in radially outwardly oiiset relation to the adjacent area of said hammer head, said arcuate body termimating at each end in a slotted nail engaging member which projects tangentially with respect to the periphery of said body in a direction substantially parallel with said handle.

References Cited in the file or this patent UNETED STATES PATENTS 176,972 Tllayer Dec. 14, 1875 368,516 Cooper et al. Aug. 16, 1887 457,526 Daly Aug. 11, 1891 872,886 Bates Dec. 3, 1907 2,283,215 Lane May 19, 1942

Claims

1. IN A HAND TOOL HAVING A HEAD WITH A NAIL STRIKING ELEMENT AT ONE END THEREOF AND A HANDLE EXTENDING AT SUBSTANTIALLY RIGHT ANGLES TO THE LONGITUDINAL AXIS OF SAID STRIKING ELEMENT; A NAIL EXTRACTING DEVICE MOUNTED ON SAID STRIKING ELEMENT AND COMPRISING A THIN BODY PORTION HAVING A SUBSTANTIALLY CYLINDRICAL BEARING SURFACE CONCENTRIC WITH RESPECT TO SAID LONGITUDINAL AXIS OF SAID STRIKING ELEMENT, SAID BEARING SURFACE OF THE SAID BODY PORTION BEING INTEGRAL WITH SAID STRIKING ELEMENT, AT LEAST ONE SIDE OF SAID BODY PORTION HAVING A PAIR OF COACTING NAIL ENGAGING LUGS PROJECTING THEREFROM IN A LINE SUBSTANTIALLY PARALLEL WITH SAID HANDLE, SAID LUGS HAVING BEARING FACES WHICH ARE TANGENTIALLY DISPOSED WITH RESPECT TO SAID BEARING SURFACE OF SAID BODY PORTION AT THEIR POINT OF INTERSECTION