US1814182A - Manufacture of detachable blades - Google Patents

Description

July 14, 1931. m. P-ARKER- 14,1 2

MANUFACTURE OF DETACHABLE BLADES Original Filed March 7; 192'? & w & m

- a 3 52: lm $9 INfiNTOR BY PM, f I. ATTORNEYS 59 fine a helical or t Patented July 14, 1931 UNITED STATES MORGAN PARKER, OF NEW YORK, N. Y.

MANUFACTURE OF DETAOHABLE BLADES Original application filed March 7, 1927, Serial No. 173,528. Divided and this application filed February 20, 1828, Serial No. 255,722. Renewed flctober 2, 1930.

This invention relates to the manufacture of replaceable blades or cutting edges for scissors. Scissors and shears which are in constant use must be continually resharpened. This is not only expensive and timeconsuming, especially if the blades are ground to a properly serrated cutting edge, as for barbers shears, but after a time the grinding wears the blades to such a condition 1 that the scissors must be discarded. In some instances too it may be diflicult to secure the services of a skillful grinder,-so that the scissors must either be poorly ground or be used when too dull for efficient cutting. Furthermore, the blades of the common type of scissors should be madeof high grade cutlery steel throughout if they are to present and retain a keen cutting edge after each grinding. This is expensive and involves dropforging difficulties.

It was early recognized that a two-part blade would solve some of these difficulties. A tool steel cutting blade welded or mechanically attached to a softer metal shank simplifies the drop-forging problem and makes a cheaper instrument, but the resharpening problem still persists. Such blades when mechanically secured to the shank, are comparatively heavy, are ground to shape like any scissor blade, and are too costly to be discarded rather than resharpened. The welded blade becomes, of course, an integral part of the shank, and the completed instrument therefore presents no advantages over scissors having blades of tool steel throughout.

The practical utility of inventions of this class requires that the scissors shanks and blades be of such design and construction as to permit of a low initial cost of production;

the cost of replacement blades to the user should be considerably lower than the ex pense of grinding; the blade should be readily and securely attachable to the shank and conveniently detachable therefrom, without the use of tools and by persons unskilled in mechanical matters; and this attachment should be possible Without taking the shanks apart or removing the king-pin.

The cutting edges of scissors commonly de= .aree dimensional curve, the

curvature depending upon the type of scissors and the work for which they are designed. To grind this curve into each blade would involve a prohibitive expense Where the blade is to be discarded after the first dulling, and I therefore make my blade straight, but so flexible as to be conformable to any curve or twist normally defined by the permanent shank on which the blade is mounted. To mount this blade in cutting position each shank is provided with a longitudinal bead or undercut rail extending along its operative edge and conforming to its curvature, and each blade is provided with a corresponding longitudinal slotted recess. The blade can therefore be slid lengthwise over the bead, and because of its universal flexibility, conforms perfectly to the curvature.

The blade of the present invention, in order that it may possess the universal flexibility so important if it is to conform to the curvature of the shank is of small transverse dimensions-thus a blade for barbers scissors of average size is about 5/64 of an inch high and about 1/32 of an inch wide. Such a blade is indeed a specially shaped steel wire. According to the present invention I have provided a method wherebysuch a wire can be rolled, drawn, tempered, ground and out tolength in a continuous operation.

In the accompanying drawings I have illustrated the various steps followedin making the blade.

In these drawings Figure 1 is an enlarged section of one form of the material from which the blade may be made; Figure 2 is an enlarged fragmentarysection ofa pair of rolls for preliminarily forming the material shown in Figure 1;-Figure 3 is an-enlarged section showing the form of the blade material after having passed through the rolls shown in F igureQ; Figure is an en largecl fragmentary section of a second pair of rolls and an enlarged elevation of a coacting mandrel and support therefor, for fur- V ther forming the blade material; Figure 5 is a an enlarged section showing the form of the blade material after havingpassed through the rails over the shown in Fig ure 4; Figure 6 is an enlarged fragmentary view of chilling dies for hardening and planishing the blade material; Figure 7 is an enlarged section of a modified form of material from which the blade may be drawn; Figure 8 is an enlarged fragmentary section of a pair of rolls for handling'the material of Figure 7; Figure 9 is an enlarged secthe blades are manufactured in lengths in the following manner: Material of triangular cross section such as shown 1n Figure 1 ..is passed, either hot or' annealed, through rolls 1''1 (Figure 2), bringing it to the gen- ,25. eral form shown in {Figure 3; I It is then reheated or re-annealed' and passed between rolls 2-2 (Figure h and over'inandrel 3, "mounted in'support a (Figure 1 4c) thereby bringing it to the form shown in Figure 5.

30 After passing through rolls 22 and over mandrel 3 and while still hot or a'fter ,ha-ving'been re heate'd by passing througha hardfningfurnace, as drawn through dies 5 and over mandrel 6"(Figure'6). These dies are preferably formed with a bell-mouth entrance7, and may be of the water-cooled type.

Their function'is to chill, harden and planish the strip and i prevent distortion thereof. :LThereafter the strip maybe tempered'in any 40 well-known manner, as by feedingit through a-bath of heated oil. ;On account of "the small cross-sectional area and consequent-lack of rigidity of the strip while "hot, it may be found desirable to feed'it downward, rather ,45 than horizontally,through the forming rolls.

"After'being tempered, the strip is fed into contact withan abrasive wheel, which grinds 'the face 8 to form'the cutting edge 9. Any

cut outs and notches required to facilitate the mounting of the blade upon the-scissors shank as' illustrated my c'o-p'ending application; Serial No. 173,528, are then ground oit and the blades out to length also by a grinding operation. 4

""InF-gure 7 's shown a material of somewhat different initial shape. This is Similarly passed while hot or annealed through rolls 101O (Figure 8),-bringing i t tothe intermediate formshown in'FigureIQQ In E this intermediate form it is drawn through a furnace and thencethrough dies 1111 (Figure 10) and over-mandrel 12 to drawclose it .to the form shown in Figure 11 and to chillyharden and planish the material in V efih such form) It willbe noted that with this modified method, the passage of the strip material through one set of rolls is eliminated, thus rendering the process more economical.

The blades may be so cheaply made by this method that when dulled they can be replaced for much less than cost of re- This application is a division of my cop'ending application, Serial No. 173,528, filed March 17', 1927:" i

I claim: 1. The'method of making detachable blades for scissors which comprises passing a continuous strip of- -metalbetween" rolls to form a continuous slotted recess extending longitudinally therethrough, drawing the shaped strip through hardening and planijshi ng dies, tempering. the strip, grinding a cuttingedge thereonand then cutting are strip into u 'nit lengths- 1 2. The method of making detachable blades for scissors in a continuous"operationwhich consistsin passing a wiredike strip of metal downward between rolls to form a longitudinal passage therethrough, heating such slotted strip' by passing it through 'affurn'ace,

hardening and "polishing by drawing it through dies, tempering and grindi g a putfting edge thereon andthen cutting' thels tr ijp into'unit lengths."

ftestimony'whereof I aflix my signature."

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