US2321706A - Knife - Google Patents

Description

June 15, 1943; l, SALSBURY 2,321,706

' KNIFE Filed Aug. 2., 1941 Je a l .2/

FOP THE HRM A Tron/va YJ Patented June 15,v 1943 canso STATES PATENT orf-FICE i KNIFE Hubertr I. `Salslmry, Oakland, Calif. Application August z, 1941, serial No. 405,200

' sciaims, (o1. 30V- 1571) My invention relates to a special form of knife which has many uses. It employs a double-edge safety razor blade as the cutting element. Such blades are made of very thin steel, are rectangular in form, and have a cutting edge on each of their longer sides. They also have two holes or perforations which are intended to align the blades in the standard safety razor. In my invention only one corner of the blade is in use at any time so that a single blade provides four available cutting edges. Safety razor blades are used because they are readily available, relatively cheap, and have a very sharp cutting edge.

An object of my invention is to provide a knife using such a safety razor blade which will hold the blade solidly in position so that considerable force may be exerted to drive the blade into the material to be cut.

Another object of the invention is to. provide ak knife of this character in which a retainer is provided for the blade, the retainer being so mounted that it can be moved to an operative position in which the blade is exposed for cutting or to a safety position in which the blade is shielded from injuryA and so covered that it cannot cut.

A still further object of my invention is to provide a knife in which the retainer may be readily moved from, or to, the operative position to, or from. the safety position by the use of the thumb of the same hand that uses the knife.

A still further object of my invention is to provide a knife which is so constructed that the blade can be quickly removed and replaced and the knife can be quickly and thoroughly cleaned.

A still further object of my invention is to provide a knife in which the blade is carried in two members which can be readily formed from sheet metal.

Further objects and .advantages will be made evident hereinafter.

In the drawing, which is for illustrative purposes only:

Fig. l is a perspective view of my invention;

Fig. 2 is a side elevational view of the knife in operative position;

Fig. 3 is a side elevational View of the knife in safety position;

Fig. 4 is a side elevational view of the knife in released position;

Fig. 5 is a side elevation of my invention with the retainer removed;

Fig. 6 is an enlarged vertical section taken on the line 6 6 of Fig. 3;

Fig. 7 is an enlarged vertical section taken on the line 'l-l of Fig. 3;

'holder 2| between the flanges 22.

Fig. 8 is a horizontal section taken on the line 8-8 of Fig.' 3;l and Fig. 9 isan enlarged horizontalsection taken on the line 9-'9 of Fig, 3.

In the form of invention disclosed in the drawing I employ a safety razor blade II which is formed of thin and hard sheet steel, which has two cutting edges I2, each on one of the longer` The blade II iscarried in a blade holder 2t which is formed of sheet metal and has a flange 22 formed on 'each side thereof. A very rigid form of blade holder is provided by rounding the handle end 23 thereof and connecting the flanges 22y by a flange 24, the flanges 22 and 24 forming` a continuous rim extending along both sides of the holder 2| andaround the handle end 23 thereof. The distance between the flanges 22 is such: that the blade II may be placed' therebetween, resting on top of the flat surface of the There are two projections 28 formed from the metal of the holder 2| and projecting upwardly therefrom in such a position as to enter the perforations I3 of the blade I I and hold it with a corner I4 of the blade I'I projecting beyond the holder 2| due to the corner of the holder being cut away as shown at 2l. A small spherical projection 28 is formed on the upper surface of the holder 2| and the flanges 22 have ears 29 formed thereon as shown.

The retainer- 3I is also formed of sheet metalv and is of the proper width to fit snugly inside the flanges 22. It is provided on its under side with depressions 32 and 33 which engage the spherical projection 28' of the holder 2l. The rounded handle end 34 of the retainer .3| is turned up slightly so that a finger or thumb nail may be inserted thereunder. A notch .35 is formed on one side of the retainer and two notches 35 are formed on the other side thereof, the notches 35 and 36 being so placed as to register with the ears 29 when the retainer is pushed into the released position. A central ridge 31 is formed on the top of the retainer and is knurled as shown at 38. 'Ihe corner of the retainer is cut away as shown at 39.

The knife is assembled as follows: The blade T II is placed on top of the holder 2| with the projections 26 in the perforations-I3 of the blade II. The retainer 2| is then pressed down on top of the blade II, the notches 35 and 36 allowing the retainerl to pass the ears 29. If now the retainer 3l is pulled toward the handle end of l retainer 3 I.

the holder 2|, the ears 29 engage the edges of the retainer 3| and hold it against the blade Il. The projection 28 then engages the depression 32 and the retainer is locked in the safety D0- sition with the blade entirely covered by the If the thumb of the user is then pressed against the ridge 3l, engaging the knurled portion 38 thereof, the retainer can be further slid toward the handle end of the holder into operative position in which the projection 28 engages the depression 33 and locks the retainer 3| with relation to the holder 2|. In this position the corner o-f the blade projects beyond both the holder 2| and the retainer 3|, exposing one end of one of the cutting edges I2. The flange 22 opposite this edge forms a convenient surface for the thumb of a user if he wishes to press the exposed cutting edge l2 into the material to be cut.A Whenever the knife is not in use, the user slides the retainer back into safety position, thus shielding the blade If at any time the cutting iedge then in use becomes dull, the blade may be removed from the holder by sliding the retainer into released position with the notches 35 and 36 in registry with the ears 29. The depression 32 is, however. so formed with relation to the projection 28 that the retainer cannot be moved from its sa-fety position to its released position merely by pressing with the thumb on the ridge 3l but the end` 34 of the retainer must be lifted by inserting the thumb nail under the turned-up portion of this end 34. This makes it necessary to proceed in a different manner to release the blade I| than is used in shifting the retainer 3| which may be shifted from operative to safety position and from safety to operative position so that the knife will not come apart unless the operator desires that it do so. When the knife is apart the members thereof can be readily cleaned. I-f a new blade is desired, it can be inserted, but it should be remembered that the blade has four cutting corners and may be reversed in the knife so as to use all four corners before a new blade is necessary.

The knife described is very useful. It may be used for opening paper cartons, making stencils, or `other art work` by tailors and dressmakers for cutting cloth or the stitches of seams, and for many other purposes.

I claim as my invention:

1. In a knife, the combination of a flat backing plate; projections projecting upwardly yfrom the top of said plate for engaging and holding in position with relation to said plate a perfor.

ated safety razor blade; a cover plate adapted to slide over said projections and to hold said blade in position on said projections; two flanges,

tudinal direction between said flanges; and ears formed on said flanges projecting inwardly from each of said flanges in such a manner as to pro,

lthe top of said plate for engaging and holding in position .with relation to said plate a perforated safety razor blade; a cover plate adapted to slide over said projections and to hold said t blade in position on said projections; two flanges,

one on eachlongitudinal edge of said backing plate, said cover Vplate sliding freely in'a longione on each longitudinal edge of said backing plate, said cover plate sliding freely in a longitudinal direction between said flanges; ears formed on said flanges projecting inwardly from each of said flanges in such a manner as to project oVer the cover plate and thus retain it in a position in which it holds said blade in engage- Y ment with said projections, the cover plate being so notched that when pushed into an extreme position said cover plate may be removed from` between the flanges, the ears passing through said notches; and a rounded projection extending A upwardly Ifrom said backing plate and lfrictionally engaging a depression in the cover plate with the-cover plate in position to expose a corner of said knife.

3. In a knife, the combination of a flat backing plate; projections projecting upwardly from the top of said plate for engaging and holding in position with relation to said plate a perforated safety razor blade; a cover plate adapted to slide over said projections and to hold said blade in position von said projections; two flanges, one on each longitudinal edge of said backing plate,

said cover plate sliding freely in a longitudinalA direction between said flanges; ears formed on said flanges'projecting inwardly from each of said flanges in such a manner as to project over the kcover plate and thus retain it in a position in which it holds said blade in engagement withsaid projections, the cover plate being so notched that when pushed into an extreme position said cover plate may be removed from between the flanges, the ears passing through said notches; and a rounded projection extending upwardly from said backing plate and frictionally engaging a depression in the cover plate with the cover plate in position to expose a corner of said knife, or engaging a second depression in the cover plate when the cover plate is in a position to cover and shield said knife.

HUBERT I. SALSBURY.

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