US2741844A - Pivot connection for the blades of scissors or shears - Google Patents

Description

April 17, 1956 E. L. SEJMAN ET AL PIVOT CONNECTION FOR THE BLADES OF SCISSORS OR SHEARS Filed Nov. 29, 1954 2 Sheets-Sheet 1 raw ,7

27 I l 25 zs I9 25 lo 2 22 f4 3nnentons EDMUND LI. EIELIMAN AND LEIULS LURENZEI (Ittomeg April 17, 1956 SEJMAN ET AL 2,741,344

PIVOT CONNECTION FOR THE BLADES OF SCISSORS OR SHEARS Filed Nov. 29, 1954 2 Sheets-Sheet 2 l 1 45 II 3nventors EDMUND LT. EELINAN AND LEILILE LDRENZU (Ittomeg United States Patent PIVOT CONNECTION FOR THE BLADES F SCISSORS OR SHEARS Edmund L.Sejman, Devon, and Louis Lorenzo, Bridgeport, Conn., assignors to The Acme Shear Company, Bridgeport, Conn, a corporation of Connecticut Application November 29, 1954, Serial No. 471,586 2 Claims. (Cl. 341-268) The present invention relates to a pivot connection for the blades of scissors or shears, and is a continuation-inpart of our co-pending application Serial Number 318,259 filed November 1, 1952.

An object of the present invention is to provide a pivot connection by means of which the tension of the blades, with respect to each other, may be readily adjusted as desired, and following such adjustment, the repeated pivotal movement of the blades will not change the adjustment.

Another object is to provide such a connection in which the means by which the adjustment of the tension of the blades with respect to each other is prevented from being loosened by spring tensioning means in combination with other novel elements of the present pivot connection.

Further objects include the providing of a pivotal connection in which the adjustment is a relatively simple matter, a connection in which the parts are of simple and inexpensive construction, and a connection which does not require any substantial alteration in the normal structure of the scissors or shear blades.

Other objects and advantages of the invention will become apparent from a consideration of the following detailed description taken in connection with the accompanying drawings wherein a satisfactory embodiment of the invention is shown. However, it is to be understood that the invention is not limited to the details disclosed but includes all such variations and modifications as fall within the spirit of the invention and the scope of the appended claims.

In the drawings:

Fig. 1 is a side view of a pair of shears embodying the invention;

7 Fig. 2 is an edge view thereof;

Fig. 3 is a perspective View, on an enlarged scale, showing theseveral parts of the pivot connection in separated relation;

Fig. 4 is a bottom view of the locking nut shown in perspective view in Fig. 3;

Fig. 5 is a top view of the spider washer shown in perspectivein Fig. 3;

Fig. 6 is a top view of the undulated Washer shown in perspective in Fig. 3; V

Fig. 7 is a transverse sectional view, on a further enlarged scale, taken along the line 7-7 of Fig. 1;

Fig. 8 is a longitudinal sectional view on the same scale as Fig. 7, taken along the line 8-8 of Fig. 1;

Fig. 9 is a side elevation of a modified form of shears, namely, pinking shears, embodying a modified form of the invention;

Fig. 10 is an edge view thereof; and

Fig. 11 is a transverse sectional View, on an enlarged scale, taken along the line 11-11 of Fig. 9.

Similar reference characters indicate corresponding parts throughout the several figures of the drawings.

Referring to the drawings, and more particularly to Figs. 1-8 thereof, the shears illustrated therein comprise a thumb blade member 19 and a finger blade member 11, these being of substantially conventional form having "ice thumb and finger engaging loops at one end of the respective blade portions. The finger blade 11 is provided with a cylindrical hole 12, and the thumb blade 10 is provided with a cylindrical hole 13 and a countersunk recess 14 of circular form.

The pivot element 15 comprises a head 16, a knurled portion 17 adjacent the head, a smooth cylindrical shank portion 18, and an externally threaded end portion 19, the latter having a diametrically disposed slot 20. This pivot element is fixed to the blade 11 by driving it into the hole 12 with a press fit, obtained by means of the knurled portion 17, which tends'dun'ng the driving operation to cut into the metal of the'blade and thereby firmly fix the pivot element against turning. The shank portion 18 of the pivot element engages the hole 13 of the blade 10 with a relatively loose, fit so as to permit of the normal tilting movement of one blade relatively to the other as the cutting edges of the blades slide over each other as the blades are opened and closed.

Within the countersunk recess 14 there is an undulated tension spring washer 21 having a pivot element receiving opening 22, said opening being of such diameter as to be engaged by the threaded portion 19 of the pivot element. Also positioned within the above said recess, above washer 21, is a spider washer 23 having a diametrically disposed bar 24 across its pivot element receiving opening 25, which opening is of such diameter as to also be engaged by the threaded portion 19, with the bar 24 disposed in the slot 20 of the pivot element so that the spider washer is locked by the pivot element against relative turning. Thus the fixing of the pivot element to the blade 11 fixes the spider washer against relative turning with respect to the blade 11.

The spider washer 23 has an upwardly projecting detent boss or rise 26 at a point on its peripheral edge, which boss is designed to be engaged in one of an annular series of radial detent notches 27 in the lower side of the nut 28. The nut 28 is designed to be screwed upon the threaded end 19 of the pivot element and bear upon the upper side of the spider washer. When the nut is tightened, it contacts the spider washer 23, and as tightening continues, the spring washer 21, in resisting compression, maintains the spider washer in yielding engagement with the nut 28. Thus during the tightening, when tension between the blades is being increased, a ratchet effect is achieved in that the boss 26 moves from one of the plurality of notches 27 to the other as the nut is turned, until the desired tension is achieved. At this point the spring washer, by maintaining pressure against the spider washer, fixes the boss in one of the said notches until such time as it is desirable to increase or decrease the tension between the blades. The notches also serve to enable the adjustment to be conveniently carried out in small and accurately measured increments. Thus in the case of sixteen notches, the adjustment from one notch to the next would be of the order of A the pitch of the thread of the nut.

As illustrated, a slot 29 is provided in the upper end of the nut and has a concave bottom surface for convenient engagement by the end of a coin for the purpose of adjusting the nut.

Pivotal movement of the blade 19 about the shank of the pivot element will not tend to rotate nut 28, as the spider Washer is fixed against rotation with respect to the pivot element and thereby provides a fixed thrust bearing surface upon which the blade may pivot. As the blade is normally under tension it exerts axial pressure upon the spider washer and the nut, and thus produces frictional resistance between the threads of the nut and thepivot element against turning. In the cutting of thick and thin material, it is desirable to change the blade tension, and this can be quickly and easily accomplished,

simply .by .engaginga .coinin the sloLof thenutandiurning it in the desired direction to increase or decrease the blade tension. I

a :In Figs. 9-11 there is illustrated'a modified form 'o'f the invention,which is shown :as embodied in pinking'shears wherein the blades are constrained against relative tilting movement at the pivot, but have a slight relative movement axially of the pivot during the cutting action. The pinking shears comprisea'thurrib blade member 31 and a finger blade member 32, these being of substantially conventional formhavingthumband finger engaging loops'at oneendof the respective blade portions, and the blades having inter-engaging pinking teeth 33 and 34.

Upon the opposed inner sides'of the blades there are respectively providedcircular bearing bosses 35 and 36, the blade 3'1 being provided with acylindercial hole 37 having'its axis centrally of and normally to the flat hearing surface of the'bosss35 and opening at its outer .end into a countersunk circular recess 40. Similarly, the blade 32 is provided with a cylindrical hole 41 coaxial with and of corresponding diameter to the hole 37 and opening at its outer end into acountersunk recess 42 of hexagonal form, which is adapted to non-rotatively receive the hexagonal head of the pivot element, as will presently more fully appear.

A circular wear washer 43, having a circular hole 44 substantially corresponding in diameter to the holes 37 and 41, is interposed between the bearing'bosses 35 and 36, and a tubular cylindrical bearing bushing 45 is engaged in the holes 37 and 41 and through the hole 44 of the washer, the fit of this bearing bushing being such as to allow relative turning movement of the blades thereon while constraining the blades against any substantial tilting action.

A pivot element 46 comprises a hexagonal head '47 and a cylindrical shank portion 48 having an externally threaded end portion 49, the latter having a diametrically disposed slot 50. This pivot element has its shank engaged through the bearing bushing 45 with its hexagonal head 47 seated in the recess 42, the hexagonal form of the recess holding the pivot element against relative turning movement with respect to the blade 32.

Within the countersunk recess 40 there is an undulated tension spring washer 21 having a pivot element receiving opening 22, said spring being of such diameter as to be engaged by the threaded portion 49 of the pivot element. Also positioned within the above said recess, above washer 21, is a spider washer 23 having a diametrically disposed bar 24 across its pivot element receiving opening 25, which opening is of such diameter as to also be engaged by the threaded portion 49, with the bar 24 disposed in the slot 50 of the pivot element so that the spider washer is locked by the pivot element against relative turning. Thus the fixing of the pivot element to the blade 32 fixes the spider washer against relative turning with respect to the said blade.

Spider washer 23 has an upwardly projecting boss 26 (Pig. at a point on its peripheral edge, which boss is designed to engage in one of a plurality of the notches 27 in the lower peripheral edge of nut 28 (Fig. 4), which is provided at its upper end with a coin engaging slot 29 having a concave bottom surface for the purpose of adjusting the nut.

notched but .are substantially the same in this embodiment as in the embodiment illustrated in Figs. 1-8 and are as hereinbefore described.

As in the first embodiment, pivotal movement of the blade 31 about the bearing bushing 45 will not tend to turn the nut 28, not only because it is of less diameter than recess 40 but also because itris in bearing engagement with and is lockingly engagedto-the spider washer 23 which is fixed against rotation with respect to the pivot element, which element in turn is "fixed 'against rotation with respect to blade member 32.

What is claimed is:

1. A pivot connection for the blades of scissors or shears, comprising first and second blade members, each having a hole therethrough in coaxial relation one to the other, a pivot element disposed in said coaxial holes, means fixing said pivot element against relative turning with respect to said first :bl'ademember, said second blade member being free to turn about said pivot-element and said pivot element "having an external thread and being disposed partially within said hole of said second blade member and projecting outwardly therefrom, said pivot element having .a diametrically disposed longitudinally extending slot, a spider washer-having 'a hole loosely engaged about the external threa or" said pivot element for free'axial movement thereon and abar extending diametrically across said hole and engaged in said slot to fix said spinder washer against relative turning movement with respect to said pivot element, detent means carried by said spider washer, tension washer means beneath said spider washer, the underside of said tension washer being in b'earingrelation with said second blade member,

a nut engaged upon said pivot element at the outer side of said spider washer, and detent means on said not for engaging said detent means of said spider washer.

2. A pivot connection for the blades of scissors or shears, comprising first and second blade members, each having a hole therethrough in coaxial relation one to the other, a pivot element disposed in said coaxial holes, means fixing said pivot element against relative turning with respect to said first blade member, said second blade member being free to turn about said pivot element and said pivot element having an external, thread and being disposed partially within said hole of said second blade member and projecting outwardly therefrom, said pivot element having a diametrically disposed longitudinally extending slot, a spider washer having a hole loosely engaged about the external thread of said pivot element for free axial movement thereon and a bar extending diametrically across said hole and engaged in said slot to fix said spider washer against relative turning movement with respect to said pivot element, an upwardly'projecting detent boss carried by said spider washer, tension washer means beneath said spider washer, the underside of said tension Washer being in bearing relation with said second blade member, a nut engaged "upon said pivot element at the outer side of said spider washer, said nut having a plurality of detent notches on its lower washer engaging side for engagement by said detent boss of said spider washer.

References Cited in the file of this patent UNITED STATES PATENTS 462,752 Weber Nov. 10, 1891 631,111 Ford Aug. 15, 1899 642,029 Wilkinson Jan. 23, 1900 780,526 Reitz -2. Jan. 24, 1905 1,488,069 Seago Mar. 25, 1924 1,778,346 Zeidler Oct. 14, 1930 2,284,664 Kissling June 2, 1942 2,511,187 Weidauer June 13, 1950

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