US1758485A - Power shears - Google Patents

Description

M y 1930 F. D. VARTANIAN 1,758,485

POWER SHEARS Filed Feb. 28, 1929 InvenZon Ha l/f D. Vizrla zian. I

Patented May 13, 1930 UNITED STATES FRANK D. VARTANIAN, OF POBTLAN D, MAINE POWER SEEABS Application filed February 28, 1929. Serial No. 843,513.

My invention relates to improvements in cutting implements of the class embodying two, bevelled edge blades pivoted together and adapted, when closed, one on the other, to out various kinds of sheet material such as cloth, tin sheet or paper, such devices, for instance as are extensively used by tailors, dress-makers or printers.

Among the general objects of my invention are: to provide a power-driven appliance easily and conveniently handled by the operator; to largely eliminate hand fatigue of the operator which accompaniesthe manual actuation of shears; and to greatly-increase the uantity of work capable of being turned out y employing power as a substitute for hand operation of these devices.

Specific objects and advantages of my improvements relate to the location of the handle of the shearsit being always above and free from contact with the material being out; actuation of the top blade only, which permits the lower blade to slide along the table beneath the material, with no movement except in a forward direction; control over the speed of oscillation of the movable blade; ability to vary the length of the cut at each stroke of the oscillatory blade, and the combined advancing and shearing cutting efi'ect produced by reciprocating as well as oscillating the movable blade.

Other objects will be a parent from the description found hereina ter in the specification, and to illustrate my invention I have prepared the accompanying drawing in which like characters of reference identify like parts in all the different views.

In the drawing,

Fig. 1 is a side elevation of my shears;

Fig. 2 is an enlarged central sectional elevation thereof, showing in fragmentary form the blades in closed position;

Fig. 3 is a view, in part, of Fig. 2, with the blades shown in open position;

Fig. 4 is a section on line 4-4:, Fig. 2;

Fig. 5 is a fragmentary view of the oscillatory blade, showing the oblong slot which permits the blade to reciprocate;

Fig. 6 is a wiring diagram illustrating the contnections required to operate the rheosta I Fig. 7 is an end view of the eccentric which drives the blade Fig. 8 is a section on line 8-8, Fi 3, and

Fig. 9 shows a modified form 0 shears, the blades being set flat-wise to the material belng cut.

Referring to the drawing, 1 is the handle, axially mounted in which is the shaft 2. On the outer end of the handle the shaft makes connection, in any approved manner, with the flexible shaft 3 which extends to some prime moveras an electric motor (not shown). 05

Fixed on the inner end of the shaft 2 is an eccentric 4, on the periphery of which normally bears the extended arm 5 of the movable blade 6. A projection 7 on the end of the eccentric intermittently engages the hump 8 on the blade 6, forcing it forwardly, or away from the handle.

A swivel 9 is secured to the arm 5, at 10, and the shank 11 extends through a helical spring 12 one end of which thrusts on the shoulder of the swivel and the opposite end is seated in the socket 13.

A thumb nut 14 is in screw-threaded engagement with the shank 11 and limits the possible inward movement of the shank and swivel. The spring 12 acts expansively to effect the separation of the blades.

Casing 15, which encloses a large portion of the actuating elements of the apparatus, has a transverse partition 16 to which is secured one end of the spring 17. The oppo site end of this spring (17) is fastened to the oscillatory blade 6, at 18, and functions to provide a tension suflicient to hold the hump 8 and the outer end of the eccentric 4 in mutual contact at all times.

The 'fixed blade 19 is secured to thecasing 15 in any convenient manner, as for instance, by the screws 20, and its bottom edge, which preferably is substantially straight, ma be I slid along and bear for its entire lengt on the surface of the table or board on which is the material to be cut. With the blade thus positioned, the handle 1 is disposed at a considerable gle a v oriz n a 1 The bolt 21 locks the two blades 6 and 19 in close face contact. It asses through a round hole 22 in blade 19 an an oblong slotted hole 23 in blade 6. A yielding engagement of the blades may be had by employing a spring washer 21 Within the casing, on the handle side of the partition 16 is formed a chamber 24 within which are the parts having to do with the operation of a rheostat, the resistance units of which, shown in Fig. 6 and identified by the character R, being preferably placed outside of the device in any convenient location.

By swinging the button 25 into various positions in the slot 26 changes in the amount of resistance in the electrical circuit are procured and thereby various different speeds of the motor M which drives the device obtained. The lay-out for the electrical circuit is diagrammatically shown in Fig. 6.

These rheostat operating elements, which for the sake of convenient reference will hereinafter be designated as the rheostat, comprise a plurality of posts 27 secured to and on one side of the insulating disc 28, a segment 29 fixed on the disc, diametrically opposite the posts 27 and connected directly to one side of the main line wires L, a ring 30 carrying an arm 31 on which is a contactor boss 32 and the previously mentioned button 25. Also disposed on the ring 30, diametrically opposite the arm 31, is another arm 33 which terminates in a portion 34 slidable on and always in contact with some portion of the segment 29. The metallic elements, including the ring, posts and segment are properly insulated from the other metallic parts as is shown in the sectional view in Fig. 2.

As the boss 32 is swung from one to another of the posts 27, the portion 34 simply swings to a corresponding diametrically opposite position on the segment 29, retaining always an unbroken circuit to the main line By observing Fig. 6 the method of placing more or less resistance in the motor circuit and consequently obtaining various different speeds of the motor will be understood.

The arm 31 is shown in two different positions, the one in full lines cutting in on the rheostat at point a. and the one in dotted lines at b. The wires from the posts 27 and segment 29 are bunched into a cable previous to passing out through the handle, and this cable, 35, extends along the side of and is attached to the flexible casing 36, the individual wires finally being secured to their proper connecting points on the rheostat R, motor M and main line switch (not shown).

In operation, the main line switch (not shown) is thrown in, closing the electrical revolutions of the motor. When the boss 32 en ages the particular post .27 which establis es the proper motor speed, the shears may be operated to beginthe cutting work.

Starting the actuation of the shears with the parts disposed as seen in Fig. 3 with the arms 5 resting on the short radius or throw of the eccentric 4, a half turn of the latter will bring the long throw uppermost and cause the arm to rise and the blade 6 to close on the blade 19; but during this movement of the eccentric the projection 7 acts to force the blade 6 forwardly, eflectiug an advancing, shearing cut on the material. The spring 12 will now be compressed and the spring 17 extended but on continued movement of the eccentric the parts will come back to the open position of the blades, as seen in Fig. 3.

It often is desirable to proceed with the cutting work by a series of short cuts rather than the full stroke capacity of the blades. This is especially the case where the cutting is to very closely follow a line. To accomplish this the nut 14 is screwed down on the shank 11 which limits the extent of opening of the blades to the required amount.

It will be noticed by reference to Fig. 1 that the lower blade is somewhat longer than the upper one. The object of this construction is to provide for there being always a portion of the under blade disposed beneath the material, otherwise were the two blades of equal length they might, when closed together pass either over or under the material as the shears were pushed along in the process of cutting.

While the shears illustrated in Fig. 1 are particularly adapted for tailoring, dressmaking and kindred lines of work it is obvious that a modified adaptation of the structural features embodied therein can be utilized in a shearing implement as shown in Fig. 9 in which the blades operate in a plane at substantially. ninety degrees from those shown in Fig. 1, and serve as hair clippers and for work such as trimming the upstanding threads or uneven portions of rugs and in fact any shearing operation which necessitates the blades being placed flat-wise on the material.

Having thus described my invention, what I claim is:

1. A device of the character described comprising a handle, a shaft axially mounted in said handle, an eccentric 011 said shaft, a forwardly extending portion on the outer end of said eccentric, a blade having a round pivoting hole therein inclinedly fixed on said handle, a second blade having an oblong pivoting hole therein, a pivot pin adapted to secure said blades in face contact, respectively, the said second blade oscillating on said first blade, an arm on said second blade adapted to engage the periphery of said eccentric, a rearwardly disposed projection on said sec ond blade adapted to intermittently engage the said end projectidn on said eccentric,

' whereby, during the period in which said blades are coming into cutting engagement the co-action of the two said projections will cause the-said second blade to'slide forwardly on the said first blade, a spring acting on said arm to disengage said blades, a spring to return said second blade after being advanced by the engagement of the two said projections, and means to ,rotate said shaft.

2. A device of the character described comprising a handle, a blade inclinedly fixed to said handle, a second blade pivotally connected to said first mentioned blade, face to face, respectively, an arm on said second blade, an eccentric engaging said arm and adapted, when rotated, to intermittently bring said blades into cutting engagement, expansible means acting on said arm to separate said blades and bring said second blade into non-cutting engagement with said first blade, means to rotate said eccentric, and means to vary, either to increase or decrease, the extent of separation of said blades predeterminately.

In testimony whereof I aflix my signature.

FRANK D. VARTANIAN.

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