US2836241A - Scissors cutters - Google Patents

Description

May 27, 1958 G. H. FRITZINGER SCISSORS CUTTERS 2 Sheets-Sheet 1 Filed May 18, 1953 May 27, 1958 e. H. FRITZINGER SCISSORS CUTTERS 2 Sheets-Sheet 2 Filed May 18, 1953 EqJLE E' lB INVENTOR 50-7 Unite States Patent G SCISSORS CUTTERS George H. Fritzinger, West Orange, N. 3.

Application May 18, 1953, Serial No. 355,680

7 Claims. (Cl. 164-43) This application is a continuation-in-part of my pending application S. N. 204,714 filed January 6, 1951 (now Patent No. 2,689,728 dated September 21, 1954).

This invention relates to novel and improved types of pivoted scissors cutters having transverse cutting blades substantially parallel to the pivot axis of the scissors mechanism. General objects of the invention are to provide scissors cutters which have short dimensions along the cutting blades for mounting in machines having narrow dimensions, which are of a type permitting complete separation of the blades, which are adapted especially for cutting strip material such as tape or the like, and which are convenient to hold in the hand and utterly safe to handle.

In machines for dispensing tough pressure-sensitive adhesive tape requiring a scissors to cut, such for example as is exemplified in my parent application above-mentioned, there is a great need for a scissors cutter which permits complete separation of the blades and which has an overall length along the blades no greater than the active length of the blades. These requirements are fulfilled by the present invention by a novel type of scissors cutter having transverse blades extending along the pivot axis of the scissors mechanism.

The present scissors cutters are also especially adapted for hand operation for cutting strip material, pruning, and so forth. For this purpose they are especially safe to handle since they can be held wholly in the palm of the hand without presenting any sharply pointed or cutting edges.

Further novel features and objects of my invention reside in the provision of novel scissors cutters of the type above-mentioned which have a uniform cutting action along the full lengths of the blades and which have a point pressure between the blades that varies according to the resisting shearing force of the material being cut.

Further objects of my invention are to provide hand scissors cutters of the type above-mentioned which have free space at right angles to the blades for feed of strip material to be cut.

These and other objects and features of my invention will be apparent from the following description and the appended claims.

In the description of my invention reference is had to the accompanying drawings, of which:

Figure 1 is a side elevational view, with parts broken away, showing one form of scissors cutter according to my invention;

Figure 2 is an end view of this scissors cutter;

Figure 3 is a fractional view taken substantially along the line 3-3 of Figure 1 showing superimposed in dashdot lines the relative positioning of the cutting edge of the npperblade just as the blades are beginning to eng Figure 4 is a fractional side elevation of a second embodiment of scissors cutter according to my invention;

Figure 5 is a fractional view taken substantially along 2,836,241 Patented May 27, 1958 the line 55 of Figure 4 and showing superimposed in dash-dot lines the relative positioning of the cutting edge of the other blade just as the blades are beginning to ens Figure 6 is a fractional side elevation of a third embodiment of scissors cutter according to my invention;

Figure 7 is a partial plan view as seen from the line 7-7 of Figure 6 when the blades are beginning to eng Figures 8 and 9 are end and side elevational views respectively of one form of hand scissors cutter according to my invention;

Figures 10 and 11 are fractional sectional views taken respectively on the lines 10-10 and 11-11 of Fig. 9;

Figures 12 and 13 are end and side elevational views respectively of a second form of hand scissors according to my invention; and

Figure 14 is a plan view of this second form of hand scissors as seen from the line 1414 of Figure 13.

In the scissors cutter shown in Figures 1, 2 and 3, one blade 10 is fixedly secured to a bracket 11 which in turn is mounted on a carrying or frame member 12 this frame member being for example a side plate of a machine fractionally shown-and the other blade 13 is pivoted on a transverse axis to a U lever 14 which in turn is pivoted to a transverse shaft 15 secured to the side plate 12 at right angles thereto. The pivot means for the blade 13 may comprise side ears 16 and 17 on the blade engaging respective apertures in the side legs of the U lever. The outer edge of the blade 10, which is its cutting edge, may be parallel to the shaft 15 so that strip material fed in directions at right angles to the shaft will not be cut on a bias. In order that the blades may engage with a progressive point contact the edge of the blade 13 is inclined to the horizontal as is clearly shown by Figure 2. For point pressure between the blades the blade 13 is urged inwardly, by a leaf spring 18 on the outer end of the U lever, against a stop pin 19 on the U lever, this stop pin being so positioned that the blades will first meet at the ends of their cutting edges as the U lever is swung upwardly. However, to alleviate critical positioning of the blades, the blade 13 is set slightly inwardly about its pivot axis beyond the position for engagement of its cutting edge with that of the blade 10 and is provided with a guide lug 20 at its point of initial contact with the blade 10, which lug is inclined outwardly to cam the pivoted blade slightly outwardly into scissors relation with the blade 10 as the blades come into engagement. This is illustrated in Figure l by adding a dotted line L showing the relative line of travel of the cutting edge of the blade 10 relative to the blade 13 as the frame members 12 and 14 are closed.

It is not known that any scissors cutter of the type shown has heretofore been provided which has a uniform cutting action along the full lengths of the blades. In accordance with the present invention, however, such uniform cutting action is achieved-i. e., a progressive point contact is obtained between the blades with a point pressure that varies directly with the resisting shearing force of the material being cut-so as to cut the tape positively, regardless of the toughness or thickness thereof, in response to a minimum actuating force. This improved action is obtained by pivoting the blade 13 to its carrying member on a transverse axis which lies in a plane which is fixed in relation to the carrying member and which contains also the line of progressive point contact between the blades as the blades are engaged. When hollow ground blades are used, the axis of the pivoted blade and its cutting edge may both lie in such fixed plane. These underlying principles will be apparent from the following detailed description.

. In. describing the present scissors. cutters, the ,term cutting angle is used to mean the angle wh1ch is between the cutting edges of the two blades when the blades are partially'engaged as viewed-along a radius line Qf'the frame pivot; shaft at right. angles to the, surface confronting faces of; the blades when they are engaged;

This angle is required unless the blades are hollow ground sojthat the blades may engage at their cutting edges'with a, progressive point'contact. ,From another viewpoint this face angle is the angle F (Figure 3) between the cutting edges of the blades as viewed in the direction of the surface path generated by the edges of the blades; Further, the term active portion-is herein used to mean the portion of each blade which is moved past the other as the blades come into full engagement. As: aforestated, 'itis desirable that the cutting edge of the stationary blade 16 be parallel to the shaft 15 so that the tapewill not be cut on a bias. Accordingly, in order to get the needed clearance for point contact between the blades, the active portion of the movable blade 13 is inclined to the shaft 15 by the'desired face angle F. For instance, the portion of the blade 13 extending from the leading guide lug to the pivot 17 may be arcuate about a center 21 of the shaft 15, as shown; or alternatively, it may be straight and be tangential to an are from the guide lug 20. about the center 21. However, the cutting edge of the blade 13 is not arcuate or tangential with respect to the same center 21 but is arcuate or tangential, asthe case may be, with respect to a center 22 displaced upwardly from the center 21 because of inclination of the blade to provide the face angle F abovedescribed.

' In order to understandthe need forinclining thepivot axis of the blade 13 on the carrying lever 14, the blade 13 isjhereinnext considered as comprising a series of incremental 'elements leading'back from successive points of its'cuttin'g edge. As to the first such element leading from the edge at the guide lug 20, reference is had in Figurel to a radius'line 23 which extends from the pivot center 21 through the pivot 17, and to a chord line 24 which extends from the leading edge of this, first element at right; angles to this radius line to intersect, therewith at 25; 1 H r e "Were the first' incremental element pivoted to the carrying member 14 at the intersection point 25, the resisting force from sliding friction of this'element with the stationary blade 10, duringthe incremental movement of the element to move its. cutting edge past the stationary blade, would be in line with the element and would not affect the point pressure produced by the spring 18. When material is: being cut the resisting shearing force tends to cam this element from the stationary blade.

The spring '18 resists such disengagement but spring pressure alone may not be sufiic'ient for positive cutting action sincea hard spot in thematerial may overcome the spring-force or else the spring may have to be made sostro'ng that hard action from sliding friction between the blades may result. To prevent the need for strong spring pressure, and yet 'to obtain positive cutting action of this first element with the stationary blade, the pivot axis of this element ispositioned on the radius line 23 beyond the intersection point 25 at the pivot 17. Thus, the resisting shearing forceeifect canbe neutralized or bemade to increase the point pressure in direct proportion to the resisting shearing force, depending on the distance thepivot 17 is set beyond the point 25.

Were the pivot axis of all of the'incremental elements of the blade 13 parallel to the shaft 15 at the pivot point 17, the. first incremental elements whose. chord lines 'are not beyond this axis would cut positively but the remaining portionv of the blade would not cutpositively since only spring pressure would be available to maintain contact of this remaining portion with the blade 10. If this parallel pivot axis were set sufiiciently beyond the intersection point 25 to be beyond the chord line of even the last incremental elementof the blade 13, as at the pivot point 16, then the first incremental elements would be at such a steep angle'to their chord lines as to lock with the blade 10 especially if the blades have a substantial length or if the distance of the blade 13 from the shaft 15 were relatively small.

However, when the pivot point for each incremental element of the pivoted blade 13 is determined in the manner explained in the preceding penultimate paragraph the successive pivot points define an axis which is in a plane common with the cutting edge of the pivoted blade, or with the medial line of the cutting'edg'eif the edge is curved, except for 'the face angle Because of this face angle'the pivot axis 16-17 is inclinedfarther from. From the shaft'15 by the, extent of the face angle. another viewpoint, the pivot axis 16-47 is positioned relative to the blades that at each point of contact between the cutting edges thereof there is substantially the same angle between the radius line of the pivot axis through that point and the tangent line of the surface path generated by the cutting edges at that point.

Since each incremental element of the blade etfectipivoted to the carrying lever 14in the samerelation to its point of contact with the stationary blade 10, there is obtained a uniform cutting action along thefull lengths of the blades to give positive cutting at all points of the blades with minimum actuating force.

In Figures 4 and 5 there is shown a second embodiment lug 28 is pivoted to the lever 14. on a transverse axis by means of ears 29 and 3t) extending-from the blade and engaging respective apertures in the lever. 14; also, this blade 27 is urged inwardly by a spring 18' against the I from an are through the guide lug 28 about the center 21, the flat shape being shown by Way of illustration. 1 As the blades are engaged the pivoted blade 27 is manned slightly outwardly about its transverse axis on thelever 14, due'to the inclination of the stationary'blade 26 by the face angle F. As in the previous embodiment the transverse axis ofithe pivoted blade on the pivots 22 and 30 isinclined to the frame pivot shaft for uniform cutting action. by r 'In my third embodiment shown in Figures 6 and 7, the movable lever referred to as 14a has fixedly mounted thereon a blade 31 with an inclined cutting edge and guide lug 31a, the active portion of the blade being flat and parallel with the shaft 15 by way of example. The other blade 32 may also be fiat, This latter bladehas cars 33 and 34 pivoted in apertures provided in opposite legs of a U bracket 37 that is mounted on the side, frame plate 12 fractionally shown. The blade 32 is urgedoutwardly about its pivot axis by a leaf spring 38 on't'he bracket 37 against a stop formed by the abutment of the upper portion ofthe blade against a lug 39 on the bracket, as shown in Figure 7. The blade 32 is inclined to the shaft-15 to the extent of the needed face angle Fr Its. pivot axis on the bracket 37 is however parallel-to the shaft 15 and at the face angle F to the blade, since the active portion of, the. other blade 31 is parallel'to the shaft 15, which is in. accord. with the. principle ofmy invention for obtaining uniform cutting action.

In Figures 8, 9, 10 and 11 there is shown a scissors" 13 ism;

incorporating my inventionand adapted to be held in the palm of the hand. This scissors comprises lower and upper, overlying frame members 40 and 41 which may, for example, be made of light metal such as aluminum and be flanged at the sides-i. e., channel-shaped-- for increased rigidity. These frame members are pivotally interconnected by a pivot rod 42 carried by a bracket 43 on the lower frame member at one end thereof. As a feature of this hand scissors, this bracket is secured to the lower frame member at one side only to provide a through space 44 (Figure 11) which is open at one side for sidewise feed of strip material between the frame members into position at right angles to the blades, as will appear. For example, the bracket has a leg 45, which may be integral with one side flange of the lower frame member, and has an overhanging arm 46. An apertured lug 47 extends upwardly from the leg 45 and a similar apertured lug 48 extends upwardly from the far end of the overhanging arm 46 to carry the pivot rod 42. The extensions of this pivot rod beyond these lugs pass through apertures in the side flanges of the upper frame member to effect the pivotal connection between the frame members. By this arrangement, the upper frame member embraces the bracket 43 to leave no exposed edges which may irritate the hand as the scissors is operated.

Mounted on the ends of the frame members 40 and 41 opposite the pivot 42 are blades 49 and 56 respectively. The blade 49 is fixedly mounted on the frame member 40 and has an active portion which may be arcuate about the pivot 42, as shown, The other blade 51 is pivoted to the frame member 41 on a cross pin 51 extending through apertures in the side flanges of this frame member, the blade having apertured cars 52 and 53 at right angles thereto which are pivoted on the cross pin. The blade 59 engages the inner side of the fixed blade 49 under pressure of a torsion spring 54 surrounding the cross pin 51, the torsion spring having straight end portions 55 and 56 one of which bears against the under side of the frame member 41 and the other against the inner side of the pivoted blade 50. To permit complete separation of the blades, the outermost position of the pivoted blade is defined for engagement with the fixed blade by abutment of the ear 52 against a lug 57 bent over from the adjacent side flange of the upper frame member; however, to alleviate critical positioning of the pivoted blade it is provided with an inclined guide lug 53 as hereinbefore described. As the frame members are closed, this guide lug abuts against the frame member 49 to define the closed positions of the frame members. The frame members are biased open by a U-shaped leaf spring 59 interposed between the upper frame member 41 and the cross arm 46 of the bracket 43, the open position being defined by abutment of an end flange 64 of the upper frame member against the bracket arm 46, as shown in Figure 9.

As in the foregoing embodiments, one of the blades in this case the pivoted blade Sit-is at a face angle to the blade 49 as appears in Figure 9. Also, because the cutting edge of the pivoted blade is inclined in the direction of its movement as appears in Figure 8 the cross pin 51 for the pivoted blade is inclined to the frame pivot axis 42, as appears in Figure 10, to get uniform cutting action along the full lengths of the blades. To facilitate insertion of material into the space between the blades from the side of the scissors cutter, the cutting angle V is obtained by inclining equally the cutting edges of both of the blades in their paths or directions of movement as shown in Figure 8.

Another hand scissors according to my invention is shown in Figures 12, 13 and 14. As will appear by the following description, this scissors differs principally from the foregoing by oifsetting sidewise the pivot between the frame members to get a through space at right angles to the blades for feed of material to be cut.

This other hand scissors may comprise flat, relatively thick frame members 61 and 62 made of plastic material. The upper frame member 62 has a pair of depending apertured lugs 63 at its back end, and the lower frame member has a pair of upstanding apertured lugs 64 which embrace the upper frame member and which are pivotally connected to the lugs 63 by a cross pin 65. At their forward ends the lower frame member 61 has a blade 66 fixedly mounted thereon and the upper frame member 62 has a blade 67 pivoted thereto on a cross pin 68. As in the foregoing hand scissors, the pivoted blade engages the inner side of the fixed blade under pressure of a torsion spring 69 coiled about the pin 68 and disposed in a recess 62a in the end of the frame member 62; also, the cutting edges of the two blades are equally inclined to provide the cutting angle C. The outermost position of the pivoted blade about its pivot pin 68 is defined by abutment of an arm 70 of the blade against the bottom wall of a notch 71 in the upper frame member. The guiding of the upper blade into scissors engagement with the lower blade is effected, when the blades are closed from fully separated positions, by an inwardly inclined guide lug 72 on the pivoted blade. The frame members are biased open by a torsion spring 73 on the cross pin 65 but are stopped by abutment of the pivot lug 63 against the lower frame member 61 (see Figure 13) to efiect complete separation of the blades. The pivoted blade is at a suitable face angle to the stationary blade as shown in Figure 13, and the pivot pin of the pivoted blade is inclined to the frame pivot axis 65 in Figure 14, the same as in the previous embodiment.

As so far specifically described this other hand scissors is seen to be basically the same as the foregoing one.

However, it distinguishes from the foregoing in obtaining free space at right angles to the blades for feed of material between the blades to be cut, by offsetting sidewise the pivoted ends of the frame members from the opposite ends which carry the blades. This offset is shown clearly by Figures 13 and 14. Preferably, the extent of offset is equal approximately to the length of the blades to obtain full clearance at right angles to the blades. A further advantage of using an offset construction as shown is that it fits conveniently in the hand for easy hand operation. Additionally, it permits a simple and rugged pivot connection between hte frame members formed by pivot lugs at both sides of the frame members as shown.

The embodiments of my invention herein particularly shown and described are intended to be illustrative and not necessarily limitative of my invention since the same are subject to changes and modifications without departure from the scope of my invention which I endeavor to express according to the following claims.

I claim:

1. A scissors mechanism for cutting tape or similar material, comprising a pair of elongated frame members pivotally interconnected on an axis generally transverse to the longitudinal dimensions thereof, transverse blades mounted on portions of said frame members remote from said frame pivot axis and having cutting edges engageable therealong as said frame members are turned towards one another, one of said blades being rigidly secured to its respective frame member, means pivotally connecting the other of said blades to its respective frame member on an axis generally transverse thereto, means biasing said pivoted blade about its pivot axis for providing a contact pressure between the blades, the edges of said blades being inclined to each other as viewed along a radius line of said frame pivot axis at right angles to the surface path generated by said edges as the blades are progressively engaged, said edges being also inclined relative to each other as viewed in the direction of said path for causing said pivoted blade to be progressively moved about its pivot axis against the force of said biasing means as the blades are progressively engaged, and the pivot axis of said pivoted blade being positioned relative to said blades -at each pointbfgcontact-between the blades along the length Of their-cntting-edgee theradius line of saidapivot axis-through saidploint is at substantially the sameangle to the tan'gent line of said surface path at said point.- t 2'. The scissors mechanismset-ferth in claim 1 wherein the pivot axis ofsaidpivoted'blade-is substantially parallel to 'said framepivot axis 'andthe cutting'edge oi -the pivoted blade'is substantially uniformly spaced frcmits said'pivot axis. 7

3-. The scissors mechanism-set forth in claim l'wherein the cutting edge of saidpivoted blade is inclined to the frame-pivot axis'as viewed-in a direction at right angles to saidpath, and the pivot axis or" the pivoted blade isinclined: to said frame pivot'axis in directions transverse to saidpath to provide a uniform cutting action between the blades along the lengthsthereof.

, 4. The scissors meehanism set forthin claim 1 wherein said frarne members areof a plate-like formation dispose-d in;spa'ced overlying relation to each other, one of said frame'members is provided with a transverse portion i joined to the frame member at only one sidether'eoiand said framemembers areofa plate-likeformation disposed in spaced overlying relation to each other, and said frame members have their pivotally interconnected portions offset from said'blades along the frame pivot axis,

to providefree space atright angles to the blades for feed of strip material to the blades to be cut.

' 61A scissors mechanism for cutting tape or similar 7 strip material, comprising --a pair of elongated frame members pivotally interconnected on an axis generally transverse totheir longitudinal dimensions, transverseblades: mounted on portions of said frame membersremote from said frame-pivot axis and having cutting;

edges engageable as said frame members are turned towards one another, one of said blades being rigidly secured to its respective frame member and havinglits cutting edge inclined in thedirection'of relative move- 7 ment-between the blades, said other blade being pivoted to its respective frame'member on an axis substantially parallel to said'frame pivot axisandhaving its cutting edge substantially at right angles to said direction and at a substantially'uniform spacing from its pivot axis,

means for biasing said other bladerabout its pivot axis to provide contact pressurebetween the blades when the blades areengaged, and the; cutting edges l of 1 said blades; being inclined relative to each other as; viewed insaidz direction to: provide a progressive point contact-between;

theicuttin-gzie'dges with retraction ofthe pivoted blade I about its pivot axis againstthe force of said biasing" means as the blades are progressively engaged.

, 7.A scissors mechanism for cutting tape or similar;

strip material, comprising a pair of elongated frame members pivotally interconnected on an axis generallytransverse to their longitudinal dimensions, transversebladeson portions ofsaid frame members remote from-' said frame pivot axis having cutting edges engageable astheframe members are turned towards one another,

one of said blades being rigidly secured to its-respective framemember, the other of said blades being pivoted to its respective frame member and extending fr'ornirspivot axis generally in the direction of movement of the blades towards one another, 'the. cutting edge of -the;

pivoted blade being inclined in said directionof movement, means biasing the pivoted blade about itspivot" axis to provide pressure between theblades when the; same-are engaged, the cutting-edges'of said blades beinginclined'relativeto each other as viewed in said direction to provide a progressive point-contact between the; blades, with retraction of'the pivoted blade about its-- pivot axis against the force of said biasing mcans,'a.s'

the blades are progressively engaged, andthe pivot axis of said pivoted blade being inclined to said frame pivot" axis to provide a uniform cutting action between the blades at all points along their cutting edges.-

References Cited in thefileof this patent UNITED STATES PATENTS:

Schuermann, Nov, 1,1898} 635,457 Yandall Oct. 24, 1 899, 1,037,154 Knowlton Aug. 27, 1912,, 1,139,572 Perry May 18 1915;

. 1,173,580 Jennings -9. Feb. 29, 1 916,, 1,490,230 Pollock Apr. 15, 1924; 1,518,151 Kennedy Dec. 9, 1924., 7 2,333,108 Krucger et a1. Nov. 2, 1943 2,351,093 Beckley June; 13,1944, 2,604,166 Turner July 22,1952

FOREIGN PATENTS 356,066 France Nov. 20, 1905 233,024 Germany Iunell, 1910 8,707 Great Britain June 12', 1915. 305,445 Germany May 7, 1918- 123,967 7 Great Britain Mar. 13,1919" 7 642,561 Great Britain Sept. 6, 1950

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