US 3166757 A
Description (OCR text may contain errors)
Jan. 26, 1965 s. DOWNS, JR 3,166,757
OFFSET DRIVING TOOL Filed Jan. 8, 1962 INVENTOR HUEBNER 8 WORREL United States Patent 3,166,757 @FFSET BRTVBNG T601 Samuel Downs, .lru, Fresno, Caliil, assignor of twentysc-ven percent each to Harold Zinlrin, Gilbert H. Bragg,
and Wiley J. Thompson, md nineteen percent to Dr.
Charles H. lass, all of Fresno, Calif.
Filed .lan. 8, 1962, Ser. N 164,793 8 Claims. ((Il. 1-47) The present invention relates to an offset drlving tool adapted to transmit a driving force at a point remote from and in offset relation to an applied force. The present invention particularly relates to a driving tool adapted to transmit the kinetic energy resulting from impact by a first object, such as a hammer, to a second object laterally offset from the first, wherein the resulting mechanical vibrations of the driving tool are to be minimized.
The present application is a continuation-impart of application Serial No. 48,475, filed August 9, 1960, now abandoned.
The tool of the present invention has particular utility in the field of laying wall-to-wall carpeting. it is extremely useful when such carpeting is overlaid a floor composed of a hard brittle substance, such as concrete or terrazzo, into which nails are to be driven. it is a common practice in this field to nail to the floor a Wooden strip in which are embedded upwardly presented carpet retention tacks. These strips are placed against the walls, or the baseboards therealong, and are subsequently overlaid by the edges of the carpet which are secured in place by the upwardly presented tacks. In the laying of carpet, it is necessary to secure such tack strips substantially continuously about the peripheral edges of the door and under any overhanging obstruction that may be mounted on the circumscribing walls. A variety of objects in the average home and ofiice cornprise such obstructions and they generally protrude outwardly from the wall in relatively closely upwardly spaced relation to the floor. Accordingly, it is impossible to drive a nail through a tack strip under such an obstruction by using a direct blow from a hammer.
Previous tools, which have been employed unsuccess fully in driving nails under such obstructions without first removing the obstruction, include conventional crowbars and other levers of varying configuration and cross-section. Levers in the cross-sectional configuration of an I- beam have also been employed wi hout a marked degree of success. The usual problem is that the tool is either too resil ent or too rigid. Consequently, the force imparted to the nail is either insufiicient to drive the nail into a concrete floor or the natural frequency of vibra tion of the tool is such that the nail is vibrated and consequently loosened in the hole formed in the concrete incident to the nail being driven into the floor. Other undesirable characteristics of such tools are the stinging mechanical vibrations transmitted to the hands of workmen employing the tools as well as audible ringing sounds produced when such tools are struck with a hammer.
Accordingly, it is an object of the present invention to provide an improved offset driving tool.
Another object is to provide an offset driving too! with silient material, with an insulative covering capable of damping the vibrations of such a tool when struck during use.
object is to provide a steel alloy specifically These, together with other objects, will become more fully apparent upon reference to the following description and accompanying drawing.
in the drawing:
FIG. 1 is a side elevation of the offset driving tool embodying the principles of the present invention.
FIG. 2 is a bottom plan view of the tool.
FIG. 3 is a vertical section of a wall and a concrete floor on which it is desired to lay wall-to-wall carpeting and a side elevation of the-subject tool as employed in securing a tack strip to the floor beneath an overhanging obstruction borne by the Wall.
FIG. 4 is a transverse, vertical section taken on line 4-4 of FIG. 1.
PK}. 5 is a view in side elevation of a modified form of the tool of the present invention.
As shown in FIG. 1, an offset driving tool embodying the principles of the present invention includes a body member it which is of substantially triangular configuration when viewed in side elevation integrally joined to the body member is a handle ll. An upwardly presented anvil portion 12 is disposed intermediate a driving end portion 13 and a fulcrum end portion 14 adjacent to the handle 11. An interconnecting web 15 joins the anvil with the driving and fulcrum end portions. The web is provided with tapering side surfaces 316 which terminate in a base edge 17. As viewed in FIG. 4, the
ch in cross-section is in the form of an inverted triangle in which the base is relatively short in relation to the height. The base and height are so proportioned to minimize the overall weight of the tool and to provide the Web with the proper degree of elasticity so that the tool will not rebound from the nail when struck a blow during use. A satisfactory proportion between the base and hei ht results by using a dimension of .75 inch for the base and a dimension of 1.75 inches for the height as indicated in PEG. 4. The anvil portion 12 is superimposed over the base of the inverted triangularly shaped Web and projects laterally to provide an upwardly presented striking area larger than that afforded by the web 15. p
The body member 19 terminates at the fulcrum end portion 14 in a downwardly presented fulcrum 20. The fulcrum is provided with a substantially convex surface to permit rocking movement of the tool about the fulcrum in a counterclockwise direction as viewed in FIG. 1.
The body member 1% is provided with a driving head 3%) remote from an in offset relation to the fulcrum 2%). The driving head includes a downwardly presented work engaging surface 31 which is tapered from a leading edge 32 remote from the fulcrum to a trailing edge 33.. With the above proportionate web dimensions, a satisfactory distance between the fulcrum 2t and the leading edge 32 has been found to be twelve inches. The anvil portion is located intermediate the leading edge and the fulcrum at a point substantially equidistantly spaced from these end portions.
The handle 11 includes a pair of legs ill integrally joined with a central-portion 41, to result in a closed type of handle. This construction precludes any portion of the handle from vibrating freely when the tool is struck a driving blow. To minimize the transmission of such vibrations to the hand of a workman employing the tool, the handle is substantially encased with an insulative cover C. The cover is formed of a resilient material having desirable vibration damping character istics. Materials such as natural and synthetic rubber and impervious plastics, such as vinyl, have been employed successfully.
f The relative locations of the anvil 12, the driving head fill, the fulcrum 2b, the distribution. of. mass of the body member lb, and the handle it are such to result in a center of gravity located within the web member at a adapted for casting the tool in the form shown.
. point intermediate the anvil and the fulcrum but nearer to the' anvil. As shown in FIG. 1, the center of gravity is located at a point approxhnately forty percent of the distance from the fulcrum to the driving head portion. It is to be noted also that the fulcrum Zil, the center of gravity, and the anvil portion 12 are substantially in align ment. This results in a balanced construction, the significance of which will be discussed below.
In FIG. 5, a second form of the tool is shown of substantially the sameconliguration as that of the tool shown in FIG. 1 except that the tool is substantially encased in an insulative cover C. Only the work engaging surface 31, the anvil portion 12 and the downwardly presented fulcrum 20 are exposed, while the remaining surfaces are insulated by the cover C. With the second form, a maximum surface area is covered with a vibration damping material.
The tool is formed of a metal having suthcient rigidity to transmit a driving blow of significant force, but the metal must be of a character having little resilience or springiness. In addition, the tool must be of a sufficiently tough material and not brittle so as to be likely to break during use. These characteristics are quite significant and brief reference is made to the composition of the preferred material specifically developed for the tool and The body and integral handle is preferably made of a cast steel alloy having an optimum composition as follows:
Carbon 25%. Manganese 1.00 to 1.50%. Silicon 60% maximum, Chromium .50 to 1.00%. Molybdenum .30 to 50%. Vanadium .08 to .l2%.
Balance consisting essentially of iron.
'Number 325 to 375.
Operation The operation of the described embodiment of the subject invention is believed to be readily apparent and is briefly summarized at this point. As an aid to describing the operation of the subject tool, reference is made to its environment of use. As illustrated in FIG. 3, a wall 42 is upwardly extended from a floor 43 having an upper surface 44. Since severe vibration problems are encountered when driving nails into concrete floors, it is to be understood that the floor 43 is of a concrete material. A wall heater 46, typifying one of several types of overhanging obstructions, is mounted on the wall and has a lower surface 47 upwardly spaced from the upper surface of the floor. A baseboard 48 is secured to the wall adjacent to the upper surface of the floor and in a conventional manner.
The subject tool is used when it is desired to secure a tack strip 59 to the floor 43 underneath a wall heater 46, or other overhanging obstruction. In actual use, the tack strip is positioned on the upper surface 44 of the floor under the lower surface 47 of the wall heater, a nail 52 is positioned on the strip, and the driving end portion 13 of the tool is extended under the wall heater and over the nail. With the convex surface of the fulcrum member 2!) rested on the floor in a laterally outwardly spaced relation to the wall heater, the work engaging surface 31 of the driving head is rested on the head of the nail. It is evident that the anvil portion 12 of the body is upwardly disposed and outwardly spaced from the wall heater. It is also evident, as illustrated in FIG. 3, that the handle ll is spaced outwardly from the wall heater on the opposite side of the anvil portion from the heater.
With the tool proportioned as above, the work engaging surface 31 is tapered from the leading edge 32 to the trailing edge 33. As shown in PEG. l, this taper provides an acute angular relationship between the surface 31 and a plane surface on which the tool is supported by the leading edge 32 and the fulcrum 2d. The angle of such relationship is such that the tangent of the angle is substantially equal to the predetermined length of the nail 52 divided by the distance between the leading edge 52 and the fulcrum it This distance is twelve inches in the particular tool illustrated; the nail length is five-eighths of an inch; and the angle of relationship between the work engaging surface 31 and the plane surface represented by the floor 43 in PEG. 1 is 3. Accordingly, the tangent of 3 is substantially equal to .625+l2; or .0524 is substantially equal to .0521. The significance of such a relationship is shown in PEG. 3 with the nail in a position to be driven by the tool. It is to be noted that the work engaging surface is substantially normal to the longitudinal axis of the nail which insures the proper initial penetration of the nail into the floor 43. This is extremely important with concrete floors into which are driven hardened steel na ls having a circular cross-section and a pointed penetrating tip. in such an environment, it is imperative that th nail be started properly to avoid chipping of the floor, which would preclude any retention of the nail.
The nail 52 is driven through the tack strip 5t! into the concrete floor 43 by striking the anvil portion 12 with a hammer 55 as illustrated in FIG. 3. The kinetic energy of the hammer is consequently transmitted by the body member 10 of the tool through the web 5 to the work engaging surface 31 of the driving head 39. In transmitting this energy, the tool operates in the nature of a third class lever in that the operating force is ap plied at a point intermediate the fulcrum and the load. Accordingly, the force available to efiect driving of the nail 52 is somewhat less at the work engaging surface 31 than the force transmitted to the anvil portion of the tool.
It is also to be noted that the distribution of mass of the tool is such that the center of gravity is located in the Web portion at a point intermediate the anvil and the fulcrum. As stated above, the anvil, fulcrum, and center of gravity are also in substantial alignment. Accordingly, when the anvil portion is struck, a short lever arm is provided for the striking force to act upon in relation to the center of gravity. This results in a tendency to rotate the tool about the center of gravity in a counterclockwise direction as viewed in FIG. 1. Since this is the same direction of rotation, or rocking movement of the tool, about the fulcrum 2%, internal stresses are minimized which greatly reduce the mechanical vibrations which would otherwise be induced in the body member it upon being struck by the hammer. Stated differently, the driving tool constitutes a third class lever adapted to transmit upon impact at the anvil portion a shock force to the driving head wherein the anvil portion is located intermediate the fulcrum and the driving head, the center of gravity of the lever is located intermediate the anvil and the fulcrum all of which are in substantial alignment, and the anvil portion is located substantially coincident with the center of percussion of the lever whereby internal stresses are minimized when the anvil is struck. In addition, the steel alloy comprising the body member is of a composition having excellent vibration damping characteristics. Therefore, vibrations resulting from the hammer blow are also minimized by the particular steel alloy utilized in casting the tool.
Althoughthe tool as a substantially rigid metallic object, will have a natural frequency of vibration upon being stimulated by a blow, the objectionable mechanical vibrations made to the hand of a workman are effectively dampened by the insulative cover indicated at C and shown in FIG. 1 as substantially encasing the handle 11. Since the handle is of a closed form having spaced legs integral with the body member and covered by a resilient material such as natural or synthetic rubber or a plastic, such as vinyl, no portion of the tool is readily available to transmit sonievibrations to the surrounding air. If it were not for the particular steel alloy and the configuration of the tool, the tool would result in a ringing sound within the audible range of humans. However, with the tool of the present invention, thisaudible sound is minimized and further prevented from being transmitted to the air through the vibration damping characteristics of the insulative material C.
As shown in the second form, the tool may be substantially totally encased by such an insulative cover to preclude the possibility of any objectionable audible ringing sound from being produced during use of the tool.
The extremely low modulus of resiliency of the steel alloy used in the tool and the damping characteristics of the alloy minimizes any vibration likely to be transmitted to the nail. Since nails driven into concrete floors may be loosened easily by vibrations transmitted to them by a working tool, it is imperative that any tool utilized in riving such nails have a minimum of vibration. .In addition, the relationship of the Work engaging surface and the fulcrum, when in an operative position, insure proper penetration of the nail.
From the foregoing, it will be evident that an improved offset driving tool has been provided which is extremely useful in such an environment. The tool also facilitates driving nails, tacks, and other fasteners, in areas where the direct use of a hammer is precluded or rendered difficult. The tool also enables application of driving force adjacent to objects which are easily damaged or broken.
Although the invention has been herein shown and described in what is conceived to be the most practical and preferred embodiments, it is recognized that departures may be made therefrom within the scope of the invention, which is not to be limited to the details disclosed herein but is to be accorded the full scope of the claims so as to embrace any and all equivalent devices and apparatus.
Having described my invention, what I claim as new and desire to secure by Letters Patent is:
1. An offset driving tool comprising an elongated body member of generally triangular configuration viewed in side elevation and having oppositely extended driving and fulcrum end portions, a driving head downwardly extended from the driving end portion and having a downwardly presented face, a fulcrum downwardly extended from the fulcrum end portion, an upwardly presented anvil portion intermediate the driving and fulcrum ends, and a web downwardly extended from the anvil portion to a base edge and extended toward the opposite end portions in a triangular configuration in side elevation, the web also being triangular in cross-section in a transverse vertical plane passing through the anvil portion, the triangular cross-section being of inverted form and tapering toward the base edge, and an upwardly presented closed handle portion integrally joined with the body member at a point adjacent to the fulcrum end, the distribution of mass of the tool being such to locate the center of gravity thereof within the web at a point intermediate the anvil portion and the fulcrum end portion.
2. An offset driving tool comprising an elongated body member of generally triangular configuration viewed in side elevation and having oppositely extended driving and fulcrum end portions, a driving head downwardly extended from the driving end portion and having a downwardly presented face, a fulcrum downwardly extended from the fulcrum end portion, an upwardly presented anvil portion intermediate and substantially equidistantly spaced from the driving and fulcrum ends, and a web downwardly extended from the anvil portion to a base edge and extended toward the opposite end portions in a triangular configuration in side elevation, the web also being triangular in cross-section in a transverse vertical plane passing through the anvil portion, the triangular cross-section being of inverted form and tapering toward the base edge, and an. upwardly presented closed handle portion integrally joined with the body member at a joint adjacent to the fulcrum end, the distribution of mass of the tool being such to locate the center of gravity thereof within the web at a point adjacent to the anvil portion and intermediate the anvil portion and the fulcrum end portion.
3. The tool of claim 2 wherein the body member and the handle portions are formed of a metal capable of producing mechanical and sonic vibrations when struck, and the handle portion is covered with a vibration damping material whereby the sonic vibrations within the human hearing range are substantially reduced and whereby the mechanical vibrations of the handle are confined to said damping material.
4. The tool of claim 2 wherein the body member and the handle portion are formed of a cast steel having a predetermined natural frequency of vibration normally capable of producing audible sounds when vibrated at said frequency and said body member and handle portion are substantially enclosed with a vibration damping material except for said driving head face, said fulcrum and said anvil portion whereby the vibrations of said tool are substantially confined to said damping material.
5. An offset driving tool adapted for driving nails of a predetermined length and comprising an elongated body member of generally triangular configuration viewed in side elevation and having oppositely extended driving and fulcrum end portions, a driving head downwardly extended from the driving end portion and having a downwardly presented face, a fulcrum downwardly extended from the fulcrum end portion at a predetermined distance from the driving head, an upwardly presented anvil portion intermediate the driving and fulcrum ends, said driving head face having a work engaging surface tapering away from a leading edge remote from said fulcrum and in slight acute angular relationship to a plane surface supporting the tool by said leading edge and fulcrum, the angle of such relationship being such that its tangent is substantially equal to said predetermined nail length divided by the distance between said fulcrum and said leading edge, and a web downwardly extended from the anvil portion to a base edge and extended between the opposite end portions, and an up wardly presented handle integrally joined with the body member at a po nt adjacent to the fulcrum end, the distribution of mass of the tool being such to locate the center of gravity thereof within the web at a point adja centto the anvil portion and intermediate the anvil portion and the fulcrum end portion.
6. An offset driving tool comprising an elongated body having opposite end portions providing respectively a driving head and a fulcrum and having an anvil portion located intermediate said driving head and fulcrum, said anvil, head and fulcrum being arranged in the nature of a third class lever, the distribution of mass of the tool being such that the center of gravity of the tool is located intermediate the anvil and the fulcrum, the respective locations of the anvil, the fulcrum and the center of gravity being such that all are in substantial alignment, and the anvil portion is located substantially coincident with the center of percussion of the tool whereby internal stresses and vibrations of the tool are minimized when the anvil is struck.
7. An offset driving tool comprising an elongated body having opposite end portions providing respectively a driving head and a fulcrum and having an anvil portion located intermediate said driving head and fulcrum, the distribution of mass of the tool being such to have a center of percussion located intermediate said driving head and the fulcrum, the distribution of the mass of the tool also disposing the center of gravity of the .tool intermediate the center of percussion and the fulcrum in substantial alignment therewith so'that internal stresses and vibrations of the tool are minimized when the tool is struck.
8. An offset driving tool comprising an elongated body having opposite end portions providing respectively a driving head and a fulcrum and having an anvil portion located intermediate said driving head and fulcrum, the distribution of mass of the tool being such to have a center of percussion located intermediate said driving head and the fulcrum, the distribution of the mass of the tool also disposing the center of gravity of the tool intermediate the center of percussion and the fulcrum with said center of gravity, said center of percussion and said fulcrum being disposed in spaced relation in a common plane so that internal stresses and vibrations of the tool are minimized when the tool is struck.
References Cited in the file of this patent UNITED STATES PATENTS 266,834 Johnston Get. 31, 1882 1,280,549 Reynolds Oct. 1, 1918 1,410,861 Erickson Mar. 28, 1922 1,495,092 Malrowski May 29, 1924 2,577,954 Di 'Pie-tro Dec. 11, 1951 2,837,421 Kron lune 3, 1958 2,949,355 Dyrliacz Aug. 16, 1960 2,968,810 Young et ai Jan. 24, 1961