US2682795A - Hand tool - Google Patents

Description

E. C. NEAL HAND TOOL July 6, 1954 Filed May 27. 1949 Patented July 6, 1954 2,682,795 HAND TOOL Ernest C. Neal, Chicago, Ill., assignor of one-half to Elmer Brandell, Chicago, Ill.

Application May 27, 1949, Serial No. 95,760

4 Claims.

t 1 The present invention relates in general to power multiplying lever systems, and has more particular reference to an improved lever system especially Well suited for incorporation in hand tools of relatively small size, including cutters, pliers, nippers, shears and the like.

An important object of the invention is to provide compact and eiicient compound lever mechanism having closable jaws, wherein the application of relatively little force on the instrument will exert relatively powerful jaw closing action.

Another important object is to provide a compound lever system providing for the movement of a working lever, about its fulcrum, by the application of force, through the medium of an auxiliary lever member, to a cam surface of the working lever, along which a cam following portion of the auxiliary lever is adapted to move during the working stroke of the auxiliary lever.

Another important object is to utilize roller means on the auxiliary lever for camming purposes with the work lever.

Another important object is to form the levers and locate the pivots thereof, and to shape the ject being to decrease such angle of attack and thereby increase such wedging action during the operating stroke ofthe apparatus; a still further object being to cause application of the force .of the auxiliary lever to the cam surface initially in a direction substantially normal thereto, while progressively decreasing the angle of attack during the operating stroke. I

Another important object is to provide a leverA mechanism of the character mentioned, wherein the auxiliary lever is provided with a pair of bearing elements adapted to operate successively in applying thrust to the work lever during the operating stroke of the mechanism; a further object being to provide the work lever with adjacent cam surfaces, one for each of the bearing elements; a still further object being to incline the cam surfaces, one with respect to the other on the work lever.

Another important object is to provide a lever mechanism, including a work lever and an auxiliary lever for moving thework lever, wherein the auxiliary lever is provided with a plurality of thrust bearing members, of which one member is further from the fulcrum of the auxiliary lever than the other, whereby the members are positioned to drivingly engage the work lever inA succession to regulate driving force on the work lever during successive stages in the operating stroke ofthe mechanism.

Another importantobject resides in providing an unusually powerful, manually operable cutter or pliers embodying the novel compound leverage system of the present invention.

The foregoing and numerous other important objects, advantages, and inherent functions of the invention will become apparent as the same is more fully understood from the following description, which, taken in connection with the accompanying drawingsy discloses preferred embodiments of the invention.

Referring to the drawings:

Fig. l is a sectional view taken longitudinally through a cutter device embodying the present invention;

Fig. 2 is a similar view of a modified form of the device, shown in relatively fully open position;

Fig, 3 is a view of the Fig. 2 device, shown in ypartially and fully closed positions;

Fig. 4 is a top view of the devices shown in Figs. 1, 2, and 3; and

, Fig. 5 is a sectional view taken substantially along the line 5-5 in Fig. 4.

To illustrate the invention, the drawings show cutting devices II particularly adapted for manual operation, the devices specifically shown being wire or rod cutters, although it will be ape parent that the invention -is not necessarily limited to the specific use to which it may be put, the same being applicable in shears of all sorts, pliers, nippers, and other devices wherein power multiplication is desirable.

As shown, the devices I I each comprise a main frame I2, which may conveniently be formed as a sheet metal stamping. At one end the frame is formed to provide a jaw I3. This jaw may, of course, be formed in any suitable, preferred or convenient fashion, but, as shown, it comprises a block I4, preferably of hardened cutting material such as tool steel, the'block being formed to desired shape to provide a cutting edge I5 and secured in the mainframe lI2 in any suitable fashion, as by welding or riveting the same in place. Adjacent the block I4 the main frame provides a mounting fol` a pivot pin I6, secured at itsopposite ends, as in a pair of spaced apart panel portions or wings II of the main frame.

The pin I6 forms a fulcrumV pivot for a lever member I8, which comprises the working lever of the system. This working lever extends between the panels II of the main frame, is pivoted on the pin IIS, and formed at one end to provide a jaw I9 in position to register and cooperate with the jaw I3 and to close on and to open with respect to said jaw, in response to relative angular movement of the lever I8 with respect to the main frame about the fulcrum pivot l5.

The lever member I8 may conveniently comprise a formed block of tool steel or other hard cutting material, and may be formed with a cutting edge 2n in position to cooperate, in registering alinement, with the cutting edge I5 when the jaws are in the relatively closed position. On the side of the pivot l5 remote from the jaw I9, the lever member le may be formed with a thrust surface 2|, and may be normally urged toward jaw open position on the fulcrum pivot I6 by biasing spring means 22, preferably comprising a helical tension spring, anchored at its opposite ends, respectively on the lever l and on the main frame I2 between the wings or panels VI thereof. This spring normally serves to yieldingly urge the lever I8 toward relatively open position on the main frame I2.

To close the working lever I8 against the influence of the spring '22, an operating lever 23 may be provided. This lever may comprise a member formed for manual operation, and it may conveniently be mounted for pivotal movement on and with respect to the main frame I2, as by means of a pivot pin 24 secured at its opposite ends in spaced apart extensions 25 of the panel portions l? of the main frame.

The Vlever 23, like the main frame, may be formed of sheet metal and may provide journal means, such as the ears 26, for pivotally mounting the auxiliary lever 23 on the pin 2d in position extending between the panel portions of the main frame. O-n one side of the pivot 24 the lever 23 provides a handle, by means of which power may be applied thereto in order to turn the same upon the pivot 24 in the performance of the operating stroke of the lever system. To this end, the main frame l2, at the end thereof remote from the jaw I3, may be formed to provde a handle 2l, whereby to hold or anchor the main frame to facilitate the movement of the lever 23 during the operation ofthe device. Preferably, the members 23 and 2'5 form cooperating handles that may be drawn together by the contraction of the hand of the operator of the device in the performance of the operating stroke.

The operating lever 23' is provided with bearing means for engagement with the thrust surface 2| of the work lever it, such thrust surface 2| providing a cam surface, and such bearing means on the operating lever preferably comprising a rroller 28. The roller 2a may conveniently be journaled on a pin 29 mounted at its opposite ends in extensions t@ of the lever 23. The roller 28 is positioned to engage and ride upon the cam surface 2| of the work lever.

In moving from the fully open position, shown in Fig. 1, during the operation of the device, closing movement of the operating lever 23 will cause the roller 28 to move from a position of initial engagement with the surface 2 I at one end thereof, in a direction toward the other end thereof. The inclination of the surface 2| is such that the effective lever arm distance between said fulcrum pivot and the point of engagement of the roller 28 on the cam surface 2| is not materially changed during the operating stroke. During the operating stroke of the mechanism, however, it will be noted that the angle of attack of the roller '28 upon the surface 2| initially takes place substantially at right angles to such surface. This angle of attack, however, during the operating stroke of the apparatus, progressively decreases, thereby effecting a wedging or toggle action between the operating lever 23 and the work lever I8, with the result that power multiplication very substantially increases during the operating stroke of the apparatus. This action is lexceedingly valuable in small, portable cutting tools, especially tools for cutting relatively heavy steel rods.

The same toggle or wedging action occurs in the operation of the device shown in Figs. 2 and k3. In this device the work lever IS is formed with a second thrust surface 2|' adjacent the surface 2|. This surface 2| may, as shown, be relatively inclined with respect to the surface 2|; rand the operating lever 23 is formed with a bearing element 28', which if desired may be in the form of a roller carried on a shaft 29 mounted on the member 23. The bearing element 23 is positioned to engage and ride on the surface 2 I during the terminal portions of the operating, jaw closing stroke of the device.

In moving from the fully open position shown in Fig. 2, during operation of the device, closing movement of the operating lever will cause the roller 28 to move from an initial position at one end o1 the cam surface 2 I, in a direction toward the other end thereof until the relative position shown in dotted lines in Fig. 3 is reached, wherein the roller or bearing element 28 comes into engagement with the thrust surface 2|. Thereafter, the element 28 will take over the thrust applying function previously performed by the roller 28. Continued movement of the operating lever 23 will apply thrust to the work lever I3 through the element 28', which may move on the thrust surface 2|' until the fully closed position of the mechanism is attained.

it will be seen that, during the initial portions of the operating stroke, the element 2B imparts relatively powerful thrust upon the working lever, which thrust is progressively augmented by the increasing wedging action which occurs due to reduction in the angle of attack of the element 2S upon the surface 2|. During the terminal portions of the stroke, when the eiement 23 is in operation the power applied'vby the operating lever may be somewhat reduced due to the greater distance of the roller 23' from the fulcruin 24; but such power reduction is not usually important during the concluding stages of the operating stroke, especially where the mechanism is embodied as a wire or rod cutter, maximum power being desirable during the initial and medial portions of the stroke. The provision of the additional element 28' allows .the operating stroke of the mechanism to be continued beyond the position at which the element 22 will commence to slip on the surface 2|; that is to say, the position where the plane through the axes of the pivots 24 and 29 makes a right angle with the thrust surface 2|.

It is thought that the invention and its numerous attendant advantages will be fully understood from the foregoing description, and it is obvious that numerous changes may be made in the form, construction and arrangement of the several parts without departing from the spirit or scope of the invention, or sacrificing any of its attendant advantages, the forms herein disclosed being preferred embodiments for the purpose of illustrating the invention.

The invention is hereby claimed as follows:

l, A hand tool comprising a main frame forming a handle at one end, a work' lever, means forming a fulcrum pi-vot for said lever on said frame adjacent the handle remote end thereof, said frame and work lever forming cooperating jaws adapted to open and close in response to relative angular movement of said lever and frame about said pivot, said lever having a pair of adjacent cani surfaces formed thereon in position spaced from said pivot, an operating lever forming a handle, a mounting pivot spaced from said fulcrum pivot for mounting said operating lever on said frame in position presenting said handles of the frame and operating lever in spaced relation to allow the same to be conveniently grasped and manually drawn together in operating the tool to close said jaws, and a pair of bearing elements mounted on the operating lever in position to successively engage each a corresponding one of said cam surfaces, whereby to drive said work lever during the jaw closing stroke.

2. A hand tool comprising a main frame forming a handle at one end, a work lever, means forming a fulcrum pivot for said lever on said frame adjacent the handle remote end thereof, said frame and work lever forming cooperating jaws adapted to open and close in response to relative angular movement of said lever and frame about said pivot, said lever having a pair of adjacent cam surfaces formed thereon in position spaced from said pivot, an operating lever forming a handle, a mounting pivot spaced from said fulcrum pivot for mounting said operating lever on said frame in position presenting said handles of the frame and operating lever in spaced relation to allow the same to be conveniently grasped and manually drawn together in operating the tool to close said jaws, and a pair of bearing elements mounted on the operating lever in position to successively engage each a corresponding one of said cam surfaces, whereby to drive said work lever during the jaw closing stroke, one of said bearing elements being disposed on said operating lever at a greater distance from the mounting pivot thereof than the other bearing element.

3. A hand tool comprising a main frame forming a handle at one end, a work lever, means lever on said frame in position presenting said handles of the frame and operating lever in spaced relation to allow the same to be `conveniently grasped and manually drawn together in operating the tool to close said jaws, and a pair of bearing elements mounted on the operating lever in position to successively engage each a corresponding one of said cam surfaces, whereby to drive said work lever during the jaw closing stroke, said cam surfaces being relatively inclined, the one with respect to the other, on said work lever.

4. A hand tool comprising a main frame forming a handle at one end, a work lever, means forming a fulcrum pivot for said lever on said frame adjacent the handle remote end thereof, said frame and work lever forming ycooperating jaws adapted to open and close in response to relative angular movement of said lever and frame about said pivot, said lever having a pair of adjacent cam surfaces formed thereon in position spaced from said pivot, an operating lever forming a handle, a mounting pivot spaced from said fulcrum pivot for mounting Vsaid operating lever on said frame in position presenting said handles of the frame and operating lever in spaced relation to allow the same to -be conveniently grasped and manually drawn together in operating the tool to close said jaws, and a pair of b-earing elements mounted on the operating lever in position to successively engage each a corresponding one of -said cam surfaces, whereby to drive said work lever 'during the jaw closing stroke, said cam surfaces being relatively inclined, t-he one with respect tothe other, on said work lever, one of said surfaces extending substantially radially of the .fulcrum pivot of the work lever, and one of said bearing elements being disposed on said operating lever at a greater dis- -tance from the mounting pivot thereof than the other bearing element, whereby said one bearing element is adapted to engage said substantially radially extending cam surface after the other bearing element has operated on the other cam surface during the initial portions of the jaw closing stroke.

References Cited in the le of this patent UNITED STATES PATENTS Number Name Date 65,523 Wright et al. June 4, 1867 401,513 Pomeroy Apr. 16, 1889 433,978 Corning et al Aug. 12, 1890 571,287 Ryder Nov. 10, 1896 923,940 Brockway June 8, 1909 1,435,131 Jacobson Nov. 7, 1922 1,483,497 Whitfield Feb. 12, 1924 2,339,880 Romano" Jan. 25, 1944 2,385,835 Neal Oct. 2, 1945 2,564,585 Shaw Aug. 14, 1951

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