US2177414A - Method of making scissors - Google Patents

Description

R O T T A WNPIWHWHHHNH... Q

Oct. 24, 1939. w. A. ZEIDLER METHOD OF MAKING scIssoRs Filed y 10, 1939 Patented ocaz4, 1939 UNITED STATES- PATENT orrica METHOD MAKING 80188038 Application May 10, 1939, Serial No. my;

3 Claims. (01. 70-104) The object of my invention is to provide a method of making scissors with removable cutting blades which will always fit accurately in the blade-retaining scissor elements and not be warped or distorted during the hardening process to which the blades are subjected in their manufacture, which hardening process forms a part of the present invention. This object is accomplished" by my invention, one embodiment of which is hereinafter more particularly set forth.

When scissors or scissor blades are manufactured according to present-day methods, the blades are stamped from perfectly flat stock and then ground to give them the proper hollow shape It required of scissor blades in order to enable them to properly function. This grinding or shaping of the blades usually causes blade distortion, particulariy when the blades are stamped from relatively thin sheet metal with the result that the scissors cutpoorly and improperly. It has also been found extremely diflicult to properly grind scissor blades near their points, with the result that in most scissors of the removable blade type, the cutting near the points of the scissors is extremely poor and ineflicient. It has also been found diflicult, if not impossible, to secure uniformity in the blades. My invention, therefore contemplates a method whereby the blades are stamped from relatively thin sheet metal and the proper shaping and curvature for the entire blade length is imparted to the blades by the method of stamping them, rather than by shaping and grinding processes so that the finished blade is provided with the necessary curvature and also a slight transverse twist enabling it to function with extreme effectiveness.

For a more detailed description of my invention, reference is to be had to the accompanying drawing, forming a part hereof, in which Fig. 1

is a plan view of a pair of scissors embodying my invention; Fig. 2 is an enlarged edge view of the same; Fig. 3 shows a portion of a scissor element with a blade fitted thereon; Fig. 4 is a side elevation of a blade when removed from the 4s holder; Figs. 5, 6, 7 and 8 are sectional views, taken on the corresponding lines oi Fig. 3; Fig. 9 shows a portion of a cylindrical surface from which blades are cut and removed, this cylindrical surface showing the way these blades are cut from'curved or arched stock; Fig. 10 is an end view of the material of Fig. 9; and Fig. 11

, shows a novel pivot for the scissors.

.improved scissors is composed of scissor I handle members 2 and 3, a pivot 4 and blades I, 5| one blade being a dapted for detachable securement to each scissor member. The blades are all made of sheet material and are identical and interchangeable.

Each scissor handle member has a conventional finger hole I, by means of which these members I may be operated about the pivot 4 in the conventional manner.- Close to the pivot 4 each handle member 2 and I has a portion removed equal to the thickness of theblade I and this .extends clear to the ends remote from the parts 6. 10

As is well known, in ordinary scissors it is necessary to give the cutting edges a peculiar shape and adjacent to them the scissors have warped or twisted surfaces. The shape and surfaces are preserved in the members 2 and 3, but these 13 members do not touch beyond the pivot, being separated at all times by at least two thicknesses of each blade 5, or the thickness of two blades 5.

Themeans for holding these blades I will now be described.

Each of these blades has a hole I which surrounds the pivot 4 and beyond this each blade has a lateral ing 8 struck therefrom (see Fig. 8) so as to enter and fit a corresponding hole 9 in a scissor memberr Near the point, as shown in as Fig. 7, an inclined lug Ill takes under a tongue Ii formed in the scissor member. These three, that is the pivot 4, the lug 8 and the lug I 0, hold the,

blade true. Each blade is inserted or removed by removing the pivot 4, separating the scissor ele- 80 ments and removing the old blade, if one be in place. by sliding the same towards the point I that the parts "i and II disengage. When a new blade is inserted the reverse occurs and the parts Ill and I i are brought into engagement and thereafter the lug I is sprung into the socket or opening 9 and the same is done for both scissor members and thereafter the members are put together and the pivot 4 inserted. This pivot is generally a screw of the conventional type. but 40 may be of the kind shown in Fig. 11.

In Fig. 11, the pivot 4 is a split screw with a central bore therein, in which is placed the sliding wedge it, which may be driven up or down, as desired. It is driven downwardly in Fig. 11 (I and then the screw 4 is adjusted until the desired tension is on the blades, and thereafter the wedge 13 is driven upwardly so as to bind.

Heretofore many eil'orts have been made to .make blades which could be shaped when the so steel is soft and annealed and then after hardening retain its shape. The shape is very important because the flt must be perfect at all times between scissor member and blade. When blades of the prior art have been tempered and II ground their shape has been changed so that an imperfect fit has resulted with a correspondingly poor success in the finished article. The problem of making blades which will always fit perfectly has been solved in the following manner.

A sheet of metal I! with a curvature corresponding to that of a. cylinder with a diameter of about 14 inches has blades cut from it leaving openings l3 as shown in Fig. 9. From these longitudinally, as is apparent from 2, butthe blades also have a very slight transverse twist as is indicated in exaggerated form, in dotted lines in Fig. 4. This twist in the blades causes the twoco-operating blades in a scissors to be held in perfect shearing relationship without requiring a too firm blade contact so that the scissors can be operated with a minimum of effort and will cut exceedingly well with but a relatively gentle contact between the two blades. When blades are made as just described, the holes 1 are punched and the parts 8 and I0 struck up, as indicated and one edge I! is ground and thereafter the blades may be hardened and inserted and used as above described. When the cutting edges become dull the cutting blades are removed and replaced as above specified.

Since the blades 5 are stamped from rela= tively thin sheet metal, it is desirous that the tempering of the same be performed in such a manner as to prevent warpage of the blades. A method in which this can be successfully performed with very satisfactory results is as follows:

Each blade is suspended within an open-ended .tube of heat-resistant material, with the interior diameter of the tube but slightly larger than the widest part of the blade, and of a length slightly larger than the length of the blade. The hole I in each of the blades provides a means by which the blade may be suspended or hung point downward within the tube. While thus disposed within the tube, the blade and tube are 7 located in the annealing furnace and subjected thereby to heat of the required temperature. After being so treated for the required period of time, the blade is next delivered directly from the tube into the cooling oil bath. To avoid contact of the heated blade with atmosphere between the heating andcooling steps, the cooling bath is preferably located adjacent to the lower open end of the tube from which the heated blade emerges, so that when the blade is released from the means which holds it suspended within the tube, it will be lowered directly into the cooling bath with no intermediate exposure to the air.

By the tempering method just described, the blade isconfined in. a. guide member, such as a tube; during the heating. step so that it cannot warp or transyersely distort under'the action of heat. Since also, the blade is directly and immediately deposited into the cooling bath from the guide tube, no intermediate exposure to atmosphere occurs and warpage' cannot occur by reason of the subjection of the heated blade. to low temperature before it reaches-the cooling bath.

While it is entirely possible that other methods of. successfully tempering the blade might be employed, the method herein described has been eminently successful in producing non-warped blades of thin material and of very consistent uniformity in curvature, and when used in conjunction with stamped-out sheet metal blades of the character described, it greatly simplifies the production of and improves the resultant product. 7

While I have shown-and described one em.- bodimentof my invention, it is obvious that it is not restricted thereto, but that it is broad enough to cover all structures that come within the scope of the annexed claims.

What I claim is:

1. The method of making scissor blades consisting in cuttin the blades from an arched or curved section of sheet metal at an oblique angle to an axis of the sheet metal section so that the resultant blade is formed with a twist without being ground.

2.. The method of making scissor blades consisting .in cutting each blade from a sheet of metal concave-convex in cross section, the blade being cuton a bias'with respect to an axis of the sheet, the blade being thereby formed having blades coni

Images