US2856687A - Scissors - Google Patents

Description

oct, 21, 195s p. BECKMANN Em 2,856,687

SCISSORS `Filed OCt. ll, 1956 United States Patent SCISSORS Paul Beckmann and Karl Rothstein, Solingen, Germany, assgnors to J. A. Henckles Zwillingswerk Aktiengesellschaft, Solingen, Germany Application October 11, 1956, Serial No. 615,402 Claims priority, application Germany October 12, 1955 2 Claims. (Cl. 30-266) The present invention relates to shears such as hand scissors. v

As is well known, conventional hand scissors are provided with cutting blades which are slightly curved from their ends to their tips in order to improve the cooperation between the cutting edges of the blades. It is also conventional to provide behind the pivot axis of the blades on the side of this pivot axis opposite from the tips of the blades and at the inner side faces of the blades which are directed toward each other enlargements or slight projections which are conventionally in the shape of half-moons, these half-moons guaranteeing that the cutting blades are urged toward each other at their inner side faces so as to provide the best possible cutting action.

The arcuate half-moon projections referred to above may be formed integrally with the cutting blades. When this is the case, Ithe cutting blades are hollow ground and then' as an entirely separate operation it is necessary to grind the arcuate projections. The grinding of the latter projections requires the use of skilled labor since it is a delicate operation which must be carefully performed.

In order to overcome the added cost of manufacturing the scissors resulting from the inclusion of the arcuate projections which must be separately ground by skilled labor, it has already been proposed to hollow grind the inner face of each blade in one single operation and to then fix to the inner face of each blade a projection which is arcuate and corresponds to the half-moon projection referred to above, these projections being fixed in any suitable way such as soldering, welding, screwing, or the like to the blades. However, it will be noted that even where the arcuate projections are originally separate from the `blades extra handling and labor cos-ts are involved in attaching the projections to the cutting blades.

One of the objects of the present invention is to overcome the above drawbacks by providing scissors with projections which will accomplish the same results as the above referred to half-moon projections but which do not require any special steps in the manufacturing proccss in order to include such projections in the scissors.

It is also an object of the present invention to provide a process for manufacturing a scissors which is far simpler than any conventional process heretofore known and which at the same time is capable of providing the scissors with the desired projections at the rear of the pivot axis of the scissors blade.

A .further object of the present invention is to provide a scissors which is characterized by great simplicity of construction, by low cost, and by great reliability in operation.

With the above objects in view, the present invention mainly consists of a scissors which includes a pair of pivotally connected cutting blades each of which has an inner face directed toward the inner face of the other blade, each of these blades have an elongated cutting edge and an elongated outer edge opposed to the cutting edge, and at a portion of each blade which is to the rear of the pivot axis thereof on the side of this pivot axis 0pposite from the tip of the blade each blade is provided with a rib extending from its inner face and extending along the outer edge of the blade, these ribs performing the function of the projections referred to above.

lt is also with the above objects in view that the present invention mainly consists of a process for manufacturing a scissors, this process including the step of hollow grinding each blade of a scissors at an inner face thereof and at a rear portion of each blade at all parts of the inner face of the rear portion except an outer edge of the blade at the rear portion thereof which is opposed to the cutting edge so as to leave at this outer edge a rib which extends from the inner face of the blade.

The novel features which are considered. as characteristic for the invention are set` forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanyingdrawings, in which:

Fig. 1 is an elevational view of a scissors according to the present invention; and

Fig. 2 is a sectional lelevational view taken along line II*II of Fig. 1 in the direction of the arrows.

As is evident from the drawings, the pair ofcutting blades 3 and 4 of the scissors are pivotally interconnected by the screw 5. These cutting blades are slightly curved along their length in a conventional manner and also they are slightly hollow ground at their inner faces which are directed toward each other, the inner hollow ground face of the cutting blade 3 being visible in Fig. l. For the sake of clarity, the hollow grinding is shown at an exaggerated scale in Fig. 2,'and it is apparent from Fig. 2 that the hollow grinding extends all the way up to the rear end of the blades, the handles 6 and 7 being respectively affixed to the rear `ends of the blades 4 and 3. The cutting blades 3 and 4 respectively have cutting edges 9 and 9', and each blade has an outer edge opposed to its cutting edge and provided at the rear portion of each blade on the side of the pivot 5 opposite from the tip thereof with a rib extending from the inner face of the blade along its outer edge. Thus, the curved rib 8 of the blade 3 is clearly visible in Fig. l extending along the rear portion of the outer edge of the blade 3 all the way up to the handle 7 which is fixed to the blade 3. ln the same way the blade 4 is provided with a correspending rib 8' which is shown in Fig. 2.

The ribs 8 and 8 are provided in the simplest possible way by hollow grinding the inner face of each blade at its rear end portion' along all parts except the outer edge of the blade. During the hollow grinding the grinding wheel is guided in such a way, or the blade is guided with respectto the grinding wheel in such a way, that the hollow grinding does not take place along the rear part of the outer edge of each blade so as to leave along this rear part of the outer edge the rib 8 or 8.

These arcuate ribs 8 and S' cause the cutting edges 9 and 9 to bear against each other inthe proper manner, and these ribs provide the same results as the heretofore conventional half-moon projections located at the inner face of each blade between its edges. Through the eX pedient of displacing the projections so that they are located at the outer edges of the blades rather than at an intermediate part of the inner face of each blade between* its edges, as is conventional, the extra step of grinding the projections or of attaching separate projections is completely avoided. The arcuate shape of the ribs facilitates the grinding of the inner face of each blade and guar antees a smooth reliable slidingof the blades with respect toeach other.

It will be noted from Fig. l that the rib 8 of the blade 3 extends along an arc whose center is spaced from the pivot- 5. The rib of theblade 4 also extends alon'g an arc whose center is spaced from the pivot 5. Therefore, during movement' of-the blades with respect to each other the arcuate ribs 8 thereof crossover each other and are at no time insubstantial alignmentwith each other or in longitudin'al engagement with each other, so that frictio-nal rubbing between the ribs is maintained at a minimum.

The invention is applicable to all forms of shears, and the ribs provided according to the invention need not have-the arcuate configuration described above andsnown inFig. 1. However, the grinding ofthe blades in such a way as to leave theribs atthe outeredges of the blades simply by notl grinding the blades at the-regionoftheir outer edges is an important feature"y off the invention.

The-particularproling oftljeouter face of each blade which is opposed toits inner face is independent of the formation of vthe innerfaceaccording tothe invention,

but it is preferable to provide eachiblade with an outerl face which is capableof being ground in one operation together with the inner face.

It will be understood thatl each ofthe elements described above, or two or moreltogether, may also find a useful application in other types: of shears differing from the types described' above.

While the invention has been illustrated and described as embodied'in scissors, it is not intended to be limited to the details shown, since various modifications and structural changes may beVY made without departing in any way fromv thespirit of'the-presentfinvention.

Without further analysis, thef foregoing will so fully reveal the gist of thel present invention that others can` by applyingcurrent knowledge readily adapt it for various applications Without omitting features that, from the standpoint of prior art, fairly constituteessential characteristics of the'generic or specific aspects of' this-invention and, therefore, such adaptations should and are intended to bev comprehended within the meaning and range of equivalence of the following; claims.

What is claimed as new and desiredtobe'` secured byy Letters Patent is:

l. A scissors comprising, in combination, a pair of pivotally interconnected'cutting` blades turnable'with respect to each other about a predetermined axis and respectively having inner side faces directed toward and engaging each other, each blade having an elongated cutting edge and an opposed outer edge, and each blade having a rib at a rear end portion thereof extending only along said outer edge thereof, said ribs of said blades respectively engaging each other during turning of said blade with respect to each other and said ribs being of an arcuate configuration and respectively having centers of curvature spaced from the turning axis of said blades, said ribs crossing over each other during turning of the blades with respect to each other, so that the area of frictional contact between said ribs is at a minimum.

2. A scissors comprising, in combination, a pair of pivotally interconnected cutting blades turnable with respect to each other about a predetermined axis and respectivelyhaving inner side faces directed toward and engaging each other, each blade having an elongated cutting edge andan opposed outer edge, and each blade having a rib at a rear end portion thereof'extending only along saidouter edge thereof, said ribs of said blades respectively engaging each other during turning of said blades with respect to each other and said ribs having no center of curvature coinciding with the turning axis ofisaid blades so. thatvsaid ribs cross over? each other during turning of the bladesl with respectto"each other,

keeping theY area offrictional contact between said ribs`v at a-rniriirnum.

References `Cited Iin thefile: of :this patent UNITED STATES PATENTSl

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