US 3152650 A
Description (OCR text may contain errors)
Oct. 13, 1964 J. L. SAVIDGE HANDLE FRAME FOR PORTABLE POWER TOOL Filed May 15, 1962 8 7 ME E MD N .l R m m SWT L A SI E M A Y B 2 6 F United States Patent Calif.
Filed May 15, 1962, Ser. No. 194,834
2 Claims. (Cl. 173-163) This invention relates generally to power tools and more particularly to a novel handle frame structure particularly adapted for use with portable power tools.
Many power tools are provided with a simple handle structure usually in the form of a pistol grip for easy manipulation of the tool. Usually, however, these tools 'are electrically driven so that the motor therefor need not be of large mass and the tool may thus readily be operated with one hand. Examples of such tools are portable power drills, buffers, and so forth. Other tools incorporate a completely self-contained motor such as a small gasoline engine for use in areas in which electricity is not available. These .tools may also be employed to operate drills, buffers, and even power saws. Such tools find considerable use in outside operations such as construction work, gardening, and so forth.
In the case of the latter type of tools incorporating a completely self-contained motor, the structure is relatively heavy. Therefore, a suitable handle frame structure is usually provided to enable easy holding of the tool by the operator. Generally, however, such handle frame structures as have been provided heretofore include a rear gripping portion for one hand and a forward gripping portion for the other hand with the center of mass of the entire tool disposed someplace between the two gripping portions. The arrangement is such that the operator must usually stand at an angle to the direction in which the tool is to be urged for a particular operation; that is, to one side of the tool in order that he may hold the same properly. As a consequence, it is oftentimes difficult for the operator to effect a desired tooling operation. For example, in drilling a hole, the tool must be guided in a substantially straight line direction. This operation is diflicult to perform if the handle grips for supporting the tool are not symmetrically placed with respect to the tool axis.
In addition to the foregoing characteristics of prior art handle frame structures for power tools, there generally is not provided any convenient means for supporting the tool on a flat surface so that the same may be readily available for operations on top of a work table. Actually, the handle frame structures as have been provided result in the tool assuming an awkward tilted position when placed on a flat surface or on the ground. Such a characteristic is undesirable as the tool may tend to rock about the frame structure and is generally not balanced to enable easy picking up, carrying, and positioning.
With the above in mind, it is a primary object of this invention to provide a greatly improved handle frame structure for a portable power tool in which the foregoing disadvantages are overcome.
More particularly, it is an object to provide a handle frame structure for a portable power tool wherein the handle grip portions for a user are so positioned as to facilitate accurate tooling operations throughout the entire movement of the tool itself.
Another important object is to provide an improved handle frame structure for a portable power tool which also serves to define a stable stand structure for the tool so that the same may be placed on a flat work surface with the axis of the tool horizontal to the surface.
3,152,650 Patented Oct. 13, 1964 Still other important objects are to provide a handle frame structure for a portable power tool in which various elements serve dual functions to provide not only easy manipulating means for the tool but also to provide protective features so that an operator is protected from the working components of the tool while using the same.
Briefly, these and many other objects and advantages of this invention are attained by providing a generally inverted U-shaped member wherein the transverse portion of the U is secured to the motor and tool in question. The downwardly extending leg portions of the U in turn define handles which are symmetrically disposed on either side of the tool axis. Further, these handles are so positioned as to lie in a vertical plane which substantially includes the center of mass of the entire tool and motor combination to the end that the same is balanoed with respect to the handles. By this arrangement, the tool is very easily manipulated and a more accurate tooling operation may be carried out because of the symmetrical gripping arrangement provided.
In addition to the foregoing, the invention contemplates the provision of a second generally V-shaped member lying in a horizontal plane beneath the motor portion of the tool with the far ends of its arms secured to the lower ends of the handles. These arms converge towards each other in a rearward direction to terminate in an apex. The arrangement is such that a stand is provided for the tool when positioned on a flat surface so that it will support itself with the axis of the tool generally parallel to the flat surface.
Stability for the U-shaped member and the V-shaped member may be provided by a third generally inverted L-shaped member which extends from the central top portion of the tool generally rearwardly in a horizontal direction and thence downwardly to connect to the apex of the V-shaped member. This third portion of the frame provides protection against inadvertent engagement by the user with the motor portion of the tool and also serves as a convenient carrying handle for the tool.
A better understanding of the invention will be had by referring to a preferred embodiment thereof as illustrated in the accompanying drawings, in which:
FIGURE 1 is an overall perspective view of the improved handle frame for the portable power tool wherein the motor portion of the tool is illustrated in dotted lines to avoid obscuring other portions of the drawing; and,
FIGURE 2 is a side elevational view of the handle structure illustrated in FIGURE 1.
Referring first to FIGURE 1, there is shown a portable power tool in the form of a drill chuck 10 arranged to be rotated about its axis A-A by a motor indicated by the dotted lines 11. Preferably, the motor 11 is mounted to a front securing plate 12 from which the drill portion 10 extends forwardly in a normal direction. Since the drill and motor themselves constitute no part of the present invention, they are merely indicated schematically.
The handle frame structure for the motor-drill unit as described comprises a first generally inverted U-shaped member 13, a second generally V-shaped horizontal member 14, and a generally inverted L-shaped member 15.
The first inverted U-shaped member 13 has its transverse central portion secured to a yoke 16 in turn forming part of the mounting plate structure 12. This central portion extends in horizontal directions generally laterally and rearwardly as indicated at 17 and 18 and thence downwardly to form extending legs 19 and 20 defining handles. Preferably, these handles are provided with grips 21 and 22 formed of vibration absorbing material such as rubber.
The second generally V-shaped member in turn includes arms 23 and 24, the free ends of which are rigidly secured to the lower ends of the legs 19 and 26. These arms, as shown, converge towards each other in a rearward direction to meet at the apex 25 of the V shape.
The third member 15 has its horizontal portion 216 secured to the front plate structure 12 and thence extends rearwardly in a horizontal direction and downwardly to define a vertical portion 27 terminating in a rigid connection to the apex 25.
With reference to both FIGURES 1 and 2, the center of gravity of the tool and motor 11 is indicated at X. The axis of the tool AA may pass through the center of gravity as shown. With particular reference to FIGURE 2, the handles 19 and 20 are generally parallel to each other and lie in a vertical plane spaced rearwardly of the front securing yoke portion 16 a distance as indicated by the letter D. This spacing is such that the vertical plane of the handles substantially includes the center of gravity X so that the tool and motor are dynamically and statically balanced With respect to a horizontal axis C passing through the handles and extending normal to the drawing in FIGURE 2. Thus, the motor and tool are balanced with respect to portions on opposite sides of the vertical plane.
In addition to the foregoing, the horizontal portion 26 of the third member is disposed vertically above the center of gravity X as indicated by the vertical axis B-B.
In FIGURE 2, there is illustrated a flat surface 28 upon which the unit is placed. In this position, it will be noted that the lower ends of the handles 18 and 19 or grip members 21 and 22 engage the surface at spaced points symmetrically disposed on either side of the axis AA of the tool. On the other hand, the apex portion 25 of the second V-shaped member may include a small footing 29 for engaging the surface 28 to provide a three point stable support for the entire tool and motor. The dimensioning of the various frame members is such that the tool axis AA will be substantially parallel to the flat surface 28 when the tool is placed in the position shown in FIGURE 2.
In operation, a user will place his hands, respectively, about the grips 21 and 22. In this position, the user himself may stand behind the tool in substantial alignment with the tool axis AA. Since the handles 21 and 22 are symmetrically placed with respect to this axis, it is a simple matter for the operator to properly align the tool for any particular tooling operation. Further, because of the positioning of the handles with respect to the center of gravity of the tool, the entire structure is very simple for the user to manipulate since any torque or rotative moments with respect to the transverse horizontal axis CC passing through the handles is balanced.
Finally, as a consequence of the provision of the third inverted L-shaped member 15, the user himself is protected from the motor 11 from accidental engagement therewith. In addition, this member lends stability to the first and second frame members in view of the rigid connection provided between the apex portion and the front mounting plate. Finally, the horizontal portion of the member is disposed vertically above the center of gravity X so that it Will serve as a convenient carrying handle for use by one hand when the tool itself is not being operated.
From the foregoing description, it will be evident that the present invention has provided a greatly improved handle frame structure for portable power tools wherein various problems encountered with prior art structures have been avoided.
' of in generally horizontal directions laterally and rearwardly and thence terminating in downwardly extending legs defining handles, said handles being substantially parallel to each other and lying in a vertical plane normal to said axis of said tool and including said center of mass; a second generally V-shaped member having the ends of its arms rigidly secured to the lower ends of said legs and converging towards each other in a rearward direction in substantially a horizontal plane to define the apex of said V-shaped member; and a third generally inverted L-shaped member having the far end of its horizontal portion secured to said plate and extending rearwardly vertically above said center of mass and thence downwardly to define a vertical portion having its end secured to the apex of said V-shaped member, whereby said handles enable gripping by the hands of a user for operating said tool with the weight of said motor and tool substantially balanced with respect to said handles, said hori zontal portion of said third member serving as a carrying handle for one hand of a user when said tool is not being operated and whereby saidsecond V-shaped member defines a stand for supporting said tool on a flat surface with said axis of said tool substantially parallel to said flat surface.
2. A handle frame according to claim 1, including handle grips of vibration absorbing material surrounding said handles.
References (Iited in the file of this patent UNITED STATES PATENTS 2,204,110 Toop June 11, 1940 2,307,519 Lefke Jan. 5, 1943 2,718,341 Seewaldt Sept. 20, 1955 2,718,908 Kiekhaefer Sept. 27, 1955 FOREIGN PATENTS 611,275 France July 3, 1926