US2337158A - Knife with built-in sharpener - Google Patents

Description

Dec. 21,1943.4 E. LQFRANK 2,337,158

KNIFE WITH BUILT-IN SHARPENER Filed May 7, 1943 /ME-ZMINVETR Patented Dec. 21, 1943 UNITED STATES PATENT OFFICE 8 Claims.

This invention covers certain improvements upon the self sharpening knife as described and claimed in patent numbered 1,890,506, dated Dec. 13, 1932, and issued to E. L. Frank et al., on a self sharpening knife, and the objects of this present invention are to provide certain improvements in the original form of the invention as set out in the said patent, including improvements in the form of the handle, the blade bar carrying the blade, the means for releasa'bly locking the blade bar or rod and integrally connected blade to their out-thrust position for use, after the blade has been suitably sharpened through the use of the invention, and the formation of the case or housing for holding the sharpening rolls as supported upon the leaf spring used for urging the sharpening rolls to the cutting edge of the knife blade.

Another object of the invention and the said improvements, is to provide in a self sharpening knife, an elongated handle open through the sides thereof and slotted through its ends to recipr-ocably engage a thin cutting blade projected through the slot of the forward end of the handle and integrally joined to a thin blade rod projected through the slot of the rear end of the handle and whereby the cutting blade may be reciprocated over sharpening devices mounted in the forward end of the handle, the rear and protruded end of the blade rod being doubled back upon itself to form a stop adapted to Contact the rear end of the handle for limiting the reciprocable movement of the blade in the process of sharpening same, the said doubled rear end being compressible for insertion through the slot of the rear end of the handle, and formed for locking engagement thereat to hold the cutting vblade in its out-thrust position for use after sharpening.

Still another object is to provide, in a self sharpening knife of the kind referred to, and including an open handle of elongated form and through which a cutting blade is reciprocably mounted from end to end through slots formed in the ends, and there being an elongated sharp- 4ener slot formed through the under side of the handle at the forward end thereofy a Sharpener element mounted through the said slot and adapted to enga-ge the cutting edge of the knife as it is reciprocated through the said handle, the said Sharpener element being mounted upon a leaf spring anchored at its inner end to the outer side vof the handle at the rear end of the slot, and

lbeing formed at its forward end so as to fold up to provide brackets adapted to operatively carry a pair of sharpening rolls to complete the said sharpening element.

With the foregoing objects and advantages in view, as also such other or additional objects and advantages as may appear from the specification, attention `is directed tothe accompanying drawing as embodying preferred forms of the said improved knife, and wherein:

Figure 1 is a side elevation yof `a knife constructed in accordance with this invention and improvements, the cutting blade being shown as fully extended for use.

Figure 2 is a longitudinal vertical `section through the assembly as shown in Figure 1, the blade however being partially retracted, as in the process of sharpening the same.

Figure 3 is a cross section on the line 3-3 of Figure 1.

Figure 4 is a cross section on the line 4 4 of Figure 1.

Figure 5 is a longitudinal cross section through the assembly as shown in Figure 1.

Figure 6 is a detail of the Sharpener element and rolls as supported in the mounting brackets, the knife blade being also shown in section, as positioned between the rolls, as in the process of sharpening the same.

Figure 7 is a detail showing a modified formation of the rear end of the doubled blade supporting rod or strip.

Figure 8 is a plan view of the blank for forming the supporting brackets of the Sharpener rolls.

This improved form of self sharpening knife comprises an elongated handle I, made of any suitable material, preferably integrally formed and with open sides as shown at 2. A blade receiving slot 3 is formed through the forward end of the handle and a blade rod receiving slot of lesser width is formed through the rear end of the handle in alignment with the slot 3. Finger depressions or holds 5 are formed on the sides of the handle at the forward end thereof, on the margin-s of the openings 2, and an elongated sharpener slot 6 is formed through the under edge or side of the handle at its forward end. A thin, elongated knife blade l, formed integrally with a thin, elongated and relatively narrow blade rod 8, are together slidably mounted through the handle, through the slots 3 and Ll, with the blade 'l disposed in the forward .slot 3 and the blade rod 8 disposed in the rear slot 4. The rearwardly protruded end 9 of the blade rod 8, is doubled atly inward upon itself, as shown at iii, and the extremity thereof is reduced and turned sharply outward as at Il, to form a stop for the unit against the outer end of the handle as the unit is moved inwardly in the process of blade sharpening. The extremity II is reduced as shown in the drawing, and the slot 4 is widened at its lower end, in an offset relation as shown at 4a, for receiving and passing the said outturned extremity or stop I I, -so that this stop may pass within the handle. The blade and blade rod being made of spring metal, the doubled and rearwardly protruded portions 9 and Ill may be pressed together for passing them into and through the slots 4, 12a, or partially therethrough, where being released, the out-turned extremity or stop Il will spring aside and engage the inner face of the end of the handle, as shown in Figures 1 and 5, and thus releasably lock the blade 'I to its out-thrust position for use, and prevent its accidental retraction into the handle. On the other hand the shoulder of the reduced extremity Il, indicated at Ila, simultaneously contacts the outer face of the handle end, that is to say the margin of the slot 4a, thus preventing the excessive projection of the knife blade 1. If preferred, the doubled end portion I may be made of a separate and thinner strip of spring metal, as shown at I2 in Figure '7, and secured to the rearwardly protruded end of the blade rod 8 by means of a rivet or screw I3, the strip I2 being joined to the outer face of the blade rod 8 and so located that the forward joined end of this element, or the forward margin thereof, will transversely align with the shoulder Ila thereof, thus providing additional stopping means adapted to contact the lateral margin of the slot 4, for preventing the excessive inward movement of the blade rod 8 and consequent excessive outthrust of the blade 1. When it is desired to renew the blade and blade rod, the rivet or screw I3 mai7 ibe removed, new elements inserted, and then positioned and joined as above pointed out.

The sharpening unit referred to generally at I A, is made of a blank of thin, spring steel as shown at I5 in Figure 6, and includes an elongated spring strip IE, formed at its forward end and at opposite sides with ears I'I and I8, and the latter having roller tabs I9 and 2D, extended forwardly at one side and rearwardly at the other side, as shown. The inner margins of the tabs I9, are out free from the strip I6 on the lines 2l. Thus as shown in the drawing the tabs I9, 2e are spaced apart longitudinally on the strip I6. They are then turned up at right angles to this strip, toward one another or toward a common plane, and the ears I'I, I8 being then also turned inwardly at right angles to the strip I6, the tabs I 9, 20 are brought squarely over onto the upper side of the strip I5 in paralleled spaced and longitudinal alignment with each other, thus completing the roller holder as indicated at 22. Knife sharpener rolls 23 are mounted in this holder side by side, on pins 24, and the tabs I9, 20 are notched as at 25, to accommodate the knife edge as it is drawn back and forth between the rolls for sharpening.

The Sharpener unit so formed is mounted in place through the slot 6 of the handle by inserting the rolls 23 up therethrough, and then securing the rear end of the spring strip I6 to the rear margin of the slot by a rivet 26. The parts are so formed and positioned that with the blade 'I fully extended, the rolls 23 will rest immediately back of the rear end of the blade and press up against the rod 8, thus holding the blade up against the handle in operative position. The blade is reinforced at its juncture with the blade rod by elongated half-round ribs 23 secured longitudinally on each side of the blade rod and blade, and overlapping at their ends the juncture of the two. The end slots 3 and 4 of the handle are then complementally enlarged as at 3b, 4b, to pass these ribs in the reciprocating movement of the blade and blade rod, in the operation of sharpening the knife.

The foregoing description fully explains the construction and operation of the invention. To sharpen the knife blade the parts El and I are pinched together, thus permitting the inward rearward movement of the blade through the slot 4, the edge of the blade riding up and passing between the rolls 23 for sharpening the blade edge, a few reciprocations of the blade suicing for the purpose. The blade rod is then thrust fully inward by pinching together parts 9 and I0, and there locked, in the manner already pointed out.

While we have herein shown a particular embodiment of the invention and the structural features thereof, this embodiment and these features may be modified within the scope of the claims. The described improvements provide a simple, sanitary and practical knife, easily made through the integral formation of the elements, and easily cleaned by virtue of the open sided handle. New blades may also be readily inserted as may be found necessary.

I claim:

l. In a device of the kind described, an elongated, frame-like handle, formed open through its medial portion and having aligned slots formed longitudinally through its ends, a thin cutting blade and a connected thin blade rod passed slidably through the handle and through the end slots thereof, for reciprocable movement therethrough, and means on the handle for sharpening the knife as it is so reciprocated.

2. In a device of the kind described, an elongated, frarne-like handle formed with a corresponding elongated opening through its medial portion from side to side, there being also a sharpening slot formed through the under side of the forward end thereof and longitudinally aligned blade slots formed through the ends thereof, the forward end margins of the medial opening through the handle at each side thereof being formed with finger recesses, a combined thin knife blade and thin blade rod passed slidably through the handle and through the end slots thereof and thus adapted for reciprocable movement therethrough, the rearwardly protruded end of the blade rod being doubled back upon itself to provide a stop against the outer end face of the handle to limit inward movement of the rod in the process of blade sharpening, and means seated through the said sharpening slot at the forward end of the handle for sharpening the knife blade as it is reoiprocated through the handle.

3. In a device according to claim 2, the extremity of the doubled back rear end of the blade rod being reduced to form an outer stop shoulder against the end of the handle, and a cooperative means for releasably locking the blade rod to its innermost position and the knife blade to its out-thrust position for use, the said co-operative means including the doubled structure at the rear extended end of the blade rod.

4. In a device according to claim 2, the knife blade being relatively wider than the blade rod and the end slots of the handle being proportioned to correspond therewith, the extremity of the doubled back rear end of the blade rod being reduced and turned outward to form an inner stop, the shoulder of this reduced extremity forming an outer stop, the rear end slot of the handle being formed with a laterally offset extension to permit the reduced extremity 0f the doubled back rear end and stop of the blade rod to pass therethrough, on the compression of this doubled end of the blade rod, and whereby the elements may be releasably locked with the knife blade projected forwardly for use to its limited extent.

5. In a device according to claim 2, the said sharpening means as seated through the said sharpening slot of the handle comprising an integrally formed, elongated spring strip having spaced roll holding tabs thereon and sharpening rolls mounted between the tabs, at the forward end of the strip, the said strip being secured at its rear end to the under side of the handle and the sharpening elements being passed upward through the sharpening slot in such position that the cutting edge of the knife blade will ride up between the sharpening rolls as the knife blade is drawn back and forth thereover.

6. In a device according to claim 1, elongated reinforcing ribs secured longitudinally at each side of the juncture of the cutting blade and blade rod.

7. In a device according to claim l, elongated reinforcing ribs secured longitudinally at each side of the juncture of the cutting blade and blade rod, the said end slots of the handle being complementally enlarged to pass the ribs on the reciprocating movement of the blade and blade rod.

8. In a device of the kind described, a blank for forming up into the Sharpener roll supporting element referred to, the said blank including an elongated spring strip formed at its forward end and at opposite sides with transversely aligned ears, the latter having pendently connected roller supporting tabs, one extended forwardly at one side and the other extended rearly at the other side, and thus arranged for turning up perpendicularly to and transversely across the upper face of the spring strip, in spaced relation one to the other, for supporting Sharpener rolls therein between, at each side of the spring strip.

EARL L. FRANK;

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