US913575A - Tension device for shears. - Google Patents

Description

c. w. SPRAGUE. TENSION DEVICE FOR SHEABS.

APPLICATION FILED AUG. 31. 190B.

Patented Feb. 23, 1909.

Wihwmea QWFW' atmncq CLARENCE W. SPRAGUE, OF PHILADELPHIA, PENNSYLVANIA.

TENSION DEVICE FOR SHEARS.

Specification of Letters Patent.

Patented Feb. 23, 1909.

Application filed August 31, 1908. Serial No. 451,065.

To all whom it may concern:

Be it known that I, CLARENCE \V. SPRAGUE, a citizen of the United States, residing at Philadelphia, in the county of Philadelphia and State of Pennsylvania, have invented certain new and useful Improvements in 'lension Devices for Shears, of which the following is a specification, reference being had therein to the accompanying drawing.

My invention relates to improvements in tension devices for shears.

The object of my invention is to provide a tension device for shears in which an even tension may be maintained between the two cutting blades and at the same time doing away with the usual harshness in ordinary tension devices now in use.

Another object of my invention is to provide a simple, cheap and effective tension device which can be readily attached to any form of shears now in use, and in which the parts can be readily replaced when they become Worn.

In the accompanying drawings, Figure 1, is a side elevation of a pair of shears showing my tension device applied thereto. Fig. 2, is a vertical, longitudinal, sectional view of Fig. 1. Fig. 3, is a detached, perspective view of the several parts forming my tension device, and which may be applied to any form of shears. Fig. 1, is a sectional view of a modification. Fig. 5, is a detached, perspective View of the cup and washers shown in the modification.

Referring now to the drawings, 1 represents one blade of a pair of shears, and 2 the other blade which are pivoted together in the usual manner by the pivot 3, all of which is of the ordinary form of shears and is simply shown to show the application of applicants tension device to the ordinary shears.

The blade 1 adjacent the pivot 3, and in rear thereof, is provided with an opening 1- extending therethrough, and which could be made during the manufacture of the shears. This opening could be drilled in the completed blade, thus making the device applicable to any ordinary shears. As before stated, the opening 41 is adjacent the pivot 3 so that the blade 2 when swinging on the pivot Will at all times cover or partially.

l i i i l i thickness of the blade. The inner sleeve is provided with the laterally extending flange 7 which rests within the enlarged portion of the opening, and the inner end of the sleeve or bushing is flush with the inner edge 8 of the blade 1, so that the same will not interfere with the movement of the blades upon each other.

The sleeve or bushing (S has at its inner end an enlarged opening 9 ending in the upper smaller opening 10 which is internally screw-tln'eaded. Extending through threaded opening 10 is a thumb-screw 11 having the enlarged head 12 by means of which the screw can be readily moved in or out, as desired. Within the said enlarged opening is a washer 12 which is made of any desired metal, and against which the inner end. of the screw 11 is adapted to bear. Vithin said enlarged opening below the washer 12, is a second washer 13 composed of rubber or other elastic material, and below this elastic washer is still another metal washer 14, the lower face of which is slightly convexed and ground smooth to allow 1t to freely pass over the upper face 15 of the lower blade 2.

The set screw bearing upon the washer 12 and the elastic washer 13 being between said washer and the washer 14, it will be seen that the washer 141 does not have a positive unyielding contact with the lower blades as those now in use, and the superposed elastic washer revents the thumb screw from being worzed loose by the movement of the blade against the disk 14 like those in which the set screw directly engages the friction disk. This produces a more effective tension device, and also provides a device which is wholly carried by the sleeve or bushing, and which forms a more effective device. The sleeve 6 may be, if desired, welded in the opening which forms a more perfect and even inner face when ground down smooth with the lower face of. the blade 1, although it can be simply applied as shown and a set screw holding it, owing to the pressure thereon through the washers. The set screw being in rear of the pivot, it

will be seen by screwing the same down wardly the outer cutter edges will be brought together.

In Figs. 4 and 5, instead of using a washer 14, I use a cup-shaped member 14 which is of a depth slightly greater than the washers 12' and 13, and in which said washers loosely fit. The cup-shaped member is of a'diameter slightly less than the opening 9, so that there will be no possibility of any binding thereof within the opening. This cupshaped member not only provides a carrying means for the washers 12' an d.13, but also has the advantage over the washer 14: of preventing the same from. accidentally slippingout-of the opening 9 shouldthe screw 3 work loose, which might. possibly be the case with the washer 14. The cup-shaped member has all other advantages of the washer 14.

Having thus described my invention, what I claim, and desire to secure by Letters Patent, is

'1. The combination with a pair of shears, of a set screw extending through one blade of the shears, a washer against which said set screw-bears, an elastic washer below the first mentioned washer, and a third washer below the elastic washer and adapted to bear against the upper face of the other blade.

2. The combination with a pair ofshears, of. a bushing set within one blade and flush with the lower face thereof, of a set screw within said bushing, a metal washer within the bushing and against which the set screw bears, an elastic washer below said metal washer, and ametal washer. below the clastic washer andbearing against the upper face of the other blade of the shears.

3. ,The combination with .a pair of. shears, of a bushing set within one blade and-flush withthe inner face thereof, said bushing having contracted outer end, a set screw screwed into said contracted outer end, a washer within said bushing and against which the setv screw bears, an elastic washer within the bushing below the first-mentioned washer, and a washer below the elastic washer and adapted to. engage the inner face of the other blade of the shears.

4. Theccombination with a pair of shears, one blade having an opening therethrough on the inside of the pivot, said blade having its inner face provided with an annular re cess surrounding said opening, a bushing within the opening and having a flange resting in the annular recess to prevent the outward 'movement of the bushing, said bushinghaving its flange flush with the in ner face of the blade and its outer end eX- tending a distance beyond the outer face of the blade, a set screw screwed through the outer extended 'end, said bushing having an enlarged bore at its inner end, a metal washer within the bushing and against which the set screw bears, an elastic washer below the metal .washer, and a second metal washer below the elastic washer and its lower face slightlyconvexed whichis adapted to bear upon the inner face of the other blade, said bushing being so positioned that the other blade at all times coversthe same and retains the washer therein.

The combination with a pair of shears, of a set screw extending through one blade .of the shears, a cup-shaped member loosely mounted in the blade below the set screw and adapted to engage the upper face of the other blade, .an elastic member within the cup-shaped member, a washer within the cup-shaped member and bearing against the elastic member, and against which the set screw is adapted to bear.

6. The combination with a pair of shears, one blade having an opening therethrough on the inside of the pivot,,said blade having its inner face provided with an annular recess surrounding the said opening, a. bushing within said opening and having a flange restingin said annular recess, to prevent the outward movement of the bushing, said bushinghaving its flange flush with the inner face of the blade and its outer end eX- tending a distance beyond the outer face of the blade, a set screw screwed through the outerembedded end, a cup-shaped member loosely mounted in the lower end of the bushing and having its closed end bearing againstthe inner face of the other blade, a flexible member within the lower end of the cup-shaped member, and a metal washer within the cup-shaped member and. against which the set screw bears.

In testimony whereof I aflix my signature in presence of two witnesses.

CLARENCE W. SPRAGUE.

Witnesses A. I. MILLIGAN, THOMAS DUNCAN.

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