US2795976A - Manufacture of cutlery - Google Patents

Description

June 1957 D. K. CUTTS ETAL 2,795,976 I MANUFACTURE OF CUTLERY Filed March 25, 1955 a f 215 i I INVENTORS .0. M/LLER ATTORNE United States Patent MANUFACTURE OF CUTLERY :Doris Kathleen Cutts' and Derek Miller, Sheflield, England Application March 25, 1953, Serial No. 344,624

Claims priority, application Great Britain March'26,'1952 6 Claims. (Cl. 76-104) This invention eoniprises-improvements in or relating 1 to the manufacture of cutlery.

In prior United States patent specification No. 2,584,470, there' is described a" process ofmaking table kife and like blades by taking lengths of hardened and ground tapered-section stock-cutting away metal toward one end to make an embryo tang and electric'ally up- 'setting a bolster b'etween tang and blade.

There-is, hovvever; sometimes difliculty in obtaining stainless steel stock which is of tapered section and ready- 1; hardenednnd the present invention is intended to provide az proeessiin which fiat unha'rdened stock may-form the I starting: material.

According to the present invention, a processof manu- The metal provided for the bolsterlrlay be:initially of the same width as that provided for the tang and the tang andbols'ter portionsof the blankmay be-left of the full thickness'ot the metal, i. e; not iground tapered when the blade is being ground tapered.

' The upsetting operation may"be carried out'by; grip- ;ping thetang portionof'the blade firml in one electrode, "gripping" the'intermediateportion 'in' a second electrode close to the front and causing the metal, as it becomes heated by the current between the electrodes, to slide through the second electrode toward the first. If this is done, and the tang portion and its electrode are caused to retract at a suitable speed during the upsetting operation, the result is a well shaped upset which does not contain any folds or cranks and bears the subsequent die-stamping operations well.

One method of carrying the invention into effect will now be described by way of example with reference to the accompanying drawings in which:

Figure l is an elevation of a completed knife blade,

Figure 2 shows part of a blank for making the same,

Figure 3 is a section upon the line 33 of Figure 2 looking in the direction of the arrows,

Figure 4 shows the blank after the upsetting operation, and

Figure 5 is a diagrammatic elevation, partly in section, of an upsetting machine.

Referring to Figure 1, the object is to produce a knife blade having a hardened and polished blade portion 11 with an edge 12, a bolster 13 and a tang 14, the bolster and tang being solid forged with the blade.

In Figure 2 there is shown a portion of the original blank from which the knife blade of Figure 1 is to be Patented June 18, 1957 made. This comprises a blade portionll, of which only a part is seen inFigure 2, and ashank portion 15. The

blade-is 'stampedtothe'outline'shown in Figure 2 in one piece with the shank 15 from steel sheet of the thickness required forthe 'backor thickest portion of the blade 11. The blade portion is thenground tapered as indicated in the sectional view, Figure 3, hardened,'polished, and if desired mirror finished. The tapered polished portion ends at theline 16, Figure 2. The shankportion 15 is made long enough to contain not only the metal for the tang 14, but also the metal for the bolster 13. The blank so prepared is then taken and placed in an electrical'upsetting machine such as that shown in Figure 5. This comprisesa mainbed having upon it two subbeds 21, 22 which are mounted on the main bed but insulated therefrom by insulating pads 23, 24,25. .The beds 21,'22 are inline with one another and separated by a short distance atthe centre as shown at 26. Each of' the sub-beds 21, 22 is machined to provide a guideway. On' the guideway of the sub-bed 22 there is-slidably mounted a work-holding vise 27 which comprises a column -portion 28 consisting of two upsetting members with a space between them, which members support a head 29 carrying a cylinder 30 for a jaw-operating hydraulic ram131. -.The ram 31.at its lower end carries an z 'upper'vise jaw 32. Below the jaw 32 is a fixed lower vise jaw 33.

Similarly, upon the sub-bed 21 is a base 37 of a second vise slidable upon the guideWays of the sub-bed 21 and havingan upstanding column 38 which carries a head'39 supportinga cylinder-'40'for a ram 41 to operate an upper'vise jaw 42 "which moves up and down a above the 'lower' fixed jaw 43.

The lower jaws 33, 43' are made of acopper alloy or other good electrically conducting material; and are connected by flexible leads,-not shown, to the secondary of a step-down transformer 'located beneath :the bed .29. Each of the'jaws :32, :33 and :42, 43*is Water cooled.

The'lower jaws have shallow-recessescut in their upper faces which fit the blank shown in Figure 2, the blank being led in the recesses so that the shankfip'ortion 15,

close tolthe blade 11, spans' thespacebetween-the two pairs ofwise' jaws, the shank -15-being1 gripped by one pair of vise-jaws and the blade '11 by the other.. Upon the base37 of one of the vise jaws there is'anextension 44111? which is a slide to receive a'sliding block: 45 which supports: one end of the blankioritheforging. Thesliding block 45 is connected through a strong compression spring 46 to a block 47 which slides on the guideway of the sub-bed 21. The block 47 can be advanced along the bed by a ram 48 projecting from a cylinder 49 supported on the bed 20. Only part of the cylinder 49 is shown.

The other vise 27 is slidable along the sub-bed 22 and carries a bracket 34 to which is secured a ram 35 projecting from a cylinder 36, the front end of which is supported in a saddle on the sub-bed 22.

Suitable controls for moving the rams 35 and 48 and for opening and closing the vise jaws 32, 42 are provided. In operation the vise 37 is fixed on the bed 21, while the vise 27 is slidable thereon. Operation of the ram 48 to push the slider 45 forward will cause the knife blank to slide through the jaws 42, 43 if the portion 15 thereof is soft enough to be deformed under the pressure available. The blank is heated by electric current passing from one pair of vise jaws to the other through the work piece, and as soon as the heat is adequate, if pressure is applied to the ram 48 the sliding movement referred to will take place and the work will be upset in the space between the two pairs of vise jaws.

At the beginning of the operation the vise jaws 32, 33 are close to the vise jaws 42, 43, but as the upsetting -2,79e,97e a I I I operation proceeds and more and more metal is pushed into the upset portion by the slider 45 moving forward (i. e. to the left as viewed in Figure 5), more space is required to accommodate the upset metal and the vise 27 is allowed to move the metal away from the vise 37 by retracting the ram 35. If the operation is suitably performed, the result is an upset portion such as is shown in Figure 4 of the drawing, at 18, a large part of the metal of the shank 15 having been pushed into the upset portion 18 and the shank reduced to the length required to form the tang 14.

It is possible in this operation either to lay the blank in the vise jaws so that the end of the blade 11 abuts against the slider 45 with the shank held in the vise jaws 32, 33, or to reverse the blade so that the end of the shank abuts against the slider 45 and the blade is held between the vise jaws 32, 33. In the former case the part of theshank which is to be upset must be along with the blade between the jaws 42, 43, and the jaws 32, 33 hold only the end portion of the shank which is to form the tang 14. The blade and the rest of the shank slide through the jaws 42, 43. In the other case the blade is gripped firmly in the jaws 32, 33 and the whole of the shank extends across the gap, through the jaws 42, 43 and up to the slider 45. In this case it is the shank which slides through the vise jaws. This latter arrangement is preferred because it obviates any risk of scratching the blade 11.

After the upset has been made, the partly completed knife blank is removed from the machine. The temper of the blade 11 is not drawn by the upsetting operation, and its finish is not spoiled. The blade is gripped in a 1 suitable water-cooled device and the upset portion 18 and the shank 15 are heated to forging temperature. The shank is shaped into the tang 14 by edgewise pressure and the upset portion 18 is shaped into the bolster 13 by stamping between dies. Any flash produced between the dies is cut off and the bolster is polished.

This produces a knife made from flat sheet steel with a hardened and polished blade and a solid forged bolster of the highest quality. Only a light polishing or mirror finishing operation is required at the junction of the blade and bolster. Preferably, the edge is set after this op eration.

We claim:

1. A process of manufacture of knife blades consisting in taking flat soft steel stock, cutting it into blanks having a blade portion at one end, a portion of reduced width at the other end'adequate to afford metal for the tang, and an intermediate portion affording metal for the bolster, hardening and grinding the blade portion only so that it is of hard tapered section, then electrically upsetting the bolster from the flat section tang without drawing the temper of the blade by gripping the tang portion firmly in a first electrode, gripping the intermediate portion in a second electrode and causing the heated metal to slide through one electrode toward the other electrode, thereafter die-shaping the bolster and tang and polishing the bolster.

2. A process as claimed in claim 1 wherein the metal in the blank which is provided for the bolster is initially of the same width as that provided for the tang, and the tang and the bolster portions are left of the full thickness of the metal when the blade portion is being ground tapered.

3. A process as claimed in claim 1 wherein the blade is mirror finished after the hardening and grinding operation.

4. A process as claimed in claim 1 wherein the metal,

' as it becomes heated by the current between the electrodes, is caused to slide through the second electrode toward the first.

5. A process as claimed in claim 1 wherein the metal, as it becomes heated by the current between the electrodes, is caused to slide through the first electrode toward the second.

6. A process of manufacture of knife blades comprising the steps of cutting a flat non-hardened, nonground and non-tapered steel stock into blanks each having a blade portion at one end, a tang portion of re duced width at the other end and an intermediate bolster portion, hardening and grinding the blade portion only so that the blade portion becomes hardened and of tapered section and the tang and bolster portions remain relatively soft and non-tapered in section, then electrically upsetting the flat bolster portion from the tang portion at the junction between the hard tapered blade portion and the soft flat bolster portion to form the bolster without drawing the temper of the blade portion by gripping the tang portion firmly in a first electrode,

References Cited in the file of this patent UNITED STATES PATENTS Wellington Sept. 17, 1929 Shelton May 30, 1933 Miller Feb. 5, 1952

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