US1670534A - Can opener - Google Patents

Description

May 22, 1928.

H. GARRISON CAN OPENER Filed April 15, 1927 Patented May 22, 1928.

umran s;

. nnnrmncnnRrsomor CHICAGO, ILLINOIS.

CAN OPENER.

Application filed-April 13, 1927. 'Seria1 No. 183,'271.

llisJa side view, showing the stock A fitted with 'ahandle, ancl knife B riveted'to fthe stock. The "cutting edges are indicated by double line's, a lower "cutting edge being essential "to the introduction of "the length- 'enedknifeinto the can. i

Fig. 2.'is .a partial top plan fvie'w, showing the knife B curvediimconformity 'to" the *contour of facircu'lar'can, 'and ha'ving a reverse curve at "H; also the strip'metal' stock bent aside .to form the'fulcrum 'memibe'rD.

Fig. '3 shows the front face of the fulcrum member D, andthe 'rrecess E by whichthe "guiding fulcrum isfformed.

Fig. a will be employed to illustrate the disadvantage of Jusinga knife of too great curvature.

Figs. 5 and 6 will be of use in explaining the method by which a knife of given curvature is adapted to a can of greater curvature.

Figs. 7, 8 and 9 will be used to explain a structural detail designed to make the successive kerfs continuous and thus prevent the formation of a jagged edge.

On account of the increase in the length of the knife, the process of insertion requires the use of a longer projection beyond the fulcrum than in the ordinary can opener of this type, a fact which involves us in a difficulty with regard to the terminal part of the knife. It is this feature of construction with which this application is particularly concerned.

It is evident that the lengthened knife must be curved if it is to be used on circular cans, and we must determine what curvature will be best adapted to cans of various diameters.

We shall find it wholly impracticable to use a knife having the curvature of a small can. One principal difficulty met with is illustrated by Fig. 4, which shows in section a knife with a curvature adapted to a can three inches in diameter,iwith its point in a vertical position about to pierce a horinontal surface. Eaince this knife must be .Fig. 4.

attached to the stock'at itsbase, it'will seen that the power applied by. direct pressure will be in line with the arrow F, but the force that produces penetration must act in'tthe direction of the arrow G, with the consequent "loss of a large component, the

largerpartini'fa'ct, of the "direct pressure.

We will, therefore, adapt the knife to the.

.curvature :of a large can and show certain modifications which will make it fit a small can 3 inches in -*diameter, andfsection o'f knife which is adaptedftoa can '5 inches in Fig. f5 shows a partial circumference; offa "diameter. P indicates-the 'pointfat "which 'the knife passes under the ttulcrum. Itis apparent "that P is too "farfrom the rim to .permit a satisfactory adjustment of the'fful crum to the Icrimp. fWe' must'move thepoint Pclose to the. rim. The simplest w'ayto do this is to bend-the knife "in-sucha manner thatitstoppl'an viewi's represented by Fig. 6. This arrangement, however, will leadto difficulty that was illustrated fby the same 'Toa'void this, I employs reverse fcurve as practically the same direction as before.

Still another difficulty in operation aris-. ing from the use of the reverse curve is that at the completion of a kerf an additional lateral cut is made by the transverse part of the knife, TH, Fig. 2, as shown at V, Fig. 7. When the. ensuing kerf is completed and the operator undertakes to move the knife into position for the next one, it catches the projecting point at V and its operation is thereby impeded. I therefore discontinue the cutting edge at T, Fig. 2, where the jog begins.

This result may be accomplished in two ways; either by a break in the contour of the edge, as shown in Fig. 8, or by substituting a blunt margin for the-cutting edge introduced into the can the reverse curve will make it somewhat diflicult to push the blade downward and forward. It'isreadily introduced by prying it backward, the upper margin of the part which projects beyond the guiding fulcrum being used as a fulcrum for that purpose, after penetration has been efiected. I y Y The blunting of the anterior part of the margin, illustrated by Fig. 9, will add to the efficiency of this fulcrum, which acts against the lower surface of the top of the can.

I claim:

1. A can opener in the form of a lever of the second class, having a guiding fulcrum formed by a recess at the end of a handled stock, and a downwardly offset uppercut knife secured to the stock and extending forward past the guiding fulcrum; said knife being laterally curved in the direction of its length and provided with an additional cutting edge on its lower margin; that portion of said. knife which projects past the end of the fulcrum-bearing stock being laterally offset by a curved jog, the direction of displacement of the offset portion being toward that side of the instrument on which liesthe center of curvatureof the directional curve of the knife; andthe upper cutting edge being forwardly interrupted by a recess in the contour o the upper margin of the knife, said recess being located approximately at the beginning of the above mentioned curved jog. I v

2. A can opener in the form of a lever of the second class,having a guiding fulcrum formed by a recess at the end of a handled stock, and a downwardly offset uppercut knife secured to the stock andextending forward past the guiding fulcrum; said knife being laterally curved in the direction of its length and provided with an additional cutting edge on its lower margin; that portion of said knife which projects past the end of the fulcrum-bearing stock being laterally offset by a curved jog, the direction of displacement of the offset portion being toward that side of the instrument on which lies the center of curvature of the direc tional curve of the knife, and the upper cutting edge being forwardly discontinued at a point located approximately at the beginning of the above-mentioned curved jog and being thence succeeded by a, blunt upper margin. i t

3. A can opener in the form of a lever of the second class, having a guiding fulcrum formed by a recess at the end of a handled stock, and a downwardly offset uppercut knife secured to the stock and extending forward past the guiding fulcrum; said knife being laterally curved in the direction of its length and provided with an additional cutting edge on its lower margin; that portion of said knife which projects past the end of the fulcrum-bearing stockbeing laterally offset by a curved jog; the direction of displacement of the offset portion being toward that side of the instrument on which lies the center of curvature of the directional curve of the knife; and a portion of the upper edge, located on that part of said knife which connects the offset portion with :the main body oftheknife, being made blunt, and of a greater thickness than that part of the upper edge which extends rearwardly from the above mentioned curved jog.

HERMAN GARRISON.

Images