US2814103A

US2814103A - Can opener

Info

Publication number: US2814103A
Application number: US591899A
Authority: US
Inventors: Robert E Mclean
Original assignee: Individual
Current assignee: Individual
Priority date: 1956-06-18
Filing date: 1956-06-18
Publication date: 1957-11-26
Anticipated expiration: 1974-11-26

Description

Nov. 26, -1957 Filed June 18, 1956 R. E. MCLEAN 2,814,103

CAN OPENER 2 Sheets-Shee1 1 l INVENToR. /Po/" E McL ed Nov. 26, 1957 R. E. MCLEAN A CAN OPENER 2 Sheets-Sheet 2 Filed June 18, 1956 INVENToR. Robe/* /W/f v BY A TORNEK United States Patent O CAN OPENER Robert 1E. McLean, Kansas City, Mo., assignor to John C. Hockery, Kansas City, Mo., as trustee Application June 18, 1956, Serial No. 591,899

12 Claims. (Cl. 30-8.5)

This invention relates to can openers and refers more particularly to a single action can opener wherein all the operative steps of opening a can (including engaging a can in the opener, puncturing the can top, shearing the top from the can and releasing the can from the opener) are performed by manipulating or rotating a single handle mounted on the can opener body or frame.

An object of the present invention is to provide an efficient single action can opener having a manufacturing cost permitting production and marketing thereof at a popular price, such single action opener embodying a number of operative features and advantages not presently found in conventional can openers.

Another object of the invention is to provide a single action can opener having a minimum number of parts, yet every element necessary for effective, positive, efcient operation, said can opener assembly and parts being of a design and quality of manufacture to achieve an extremely long operating life for the opener.

Another object of the invention is to provide a single action can opener in which the operative elements of the opener are of such design and construction, compared to those of competitive devices of comparable quality and eiciency of operation, as to give the inventive device a competitive advantage in the highly competitive can opener market.

A primary object of the invention is to provide, in a single action can opener, a very simple, reliable, effective and economical means or mechanism to enable the operator to perform the entire operative can opening cycle by manipulating or rotating a single handle.

Another object of the invention is to provide a single action can opener employing rotation of but a single handle on the opener to perform all the operations of opening a can, wherein a minimum amount of application of force is required on the part of the operator in the steps of puncturing the end of the can and shearing the end from the can.

As commonly known, in conventional can openers employing a single operating handle, an escapement mechanism is usually employed in the steps of engaging and releasing a can, thereby requiring additional eifort on the part of the user to rotate the handle in these stages of the operation. An object of the present invention, therefore, is to eliminate the requirement of the use of additional force in these phases of the operation, this advantage being achieved by an operating mechanism in which no escapement takes place.

Another object of the invention is to provide a single l action can opener having mechanism thereon for per-k forming all of the essential operating steps of opening a can by rotation of a single handle, said mechanism being of extremely simple construction and replacing conventional complicated, more precise, and more expensive escapement mechanisms employed on conventional can openers.

2,814,103 Patented Nov. 26, 1957 Other and further objects of the invention will appear in the course of the following description thereof.

In the drawings, which form a part of the instant application and are to be read in conjunction therewith, an embodiment of the invention is shown and, in the various views, like numerals are employed to indicate like parts.

Fig. 1 is a side view of the handle side of the inventive can opener, the handle assembly being shown in full lines in one operative position and in dotted lines at another operative position.

Fig. 2 is a side view of the opposite side of the can opener shown in Fig. 1, the showing in full lines illustrating the parts of the can opener in one operative position and the showing in dotted lines illustrating the can opener parts in another operative position.

Fig. 3 is an end view of the inventive can opener.

Fig. 4 is a plan view of the inventive can opener.

Fig. 5 is :an exploded perspective view of the inventive can opener showing the parts of the handle assembly spaced relative the can opener frame or body.

Fig. 6 is a view taken along the lines 6-6 of Fig. 2 in the direction of the arrows.

Fig. 7 is a View taken along the lines 7--7 of Fig. 2 in the direction of the arrows.

Referring to the drawings, frame 10 has base portion 11 extending at right angles thereto and xedly attached by welding or riveting to base plate 12. Spring receiving flange 13 is formed in the surface of the frame l0 and has opening 14 in the face thereof. The flange 13 is formed outwardly from one face of the frame 10 suciently to receive the end of a coil spring (to be later described) -therein without the end of the spring extending outwardly past the opposite face of the frame. Rear can guide 15 extends outwardly at an angle from one face of the frame 1t) and may be formed therefrom, therby leaving opening 16 in the frame 1). Opening 17 may be formed in the forward part of the frame 10 for a purpose to be later described. Slot 18, best seen in Figs. 5 and 6, extends through the frame 10. Cutter wheel post receiving frame portion 19 is formed by outwardly an. gling Ka portion of the frame 10 above the slot 18 as best seen in Figs. 2 and 6. The frame above the portion 19 thereof is preferably grooved `as shown at 20 to receive the lower end of a magnet holding arm (not shown). Cutter wheel post receiving frame por-tion 19 has opening 19a formed therein to receive cutter wheel post 21 therein. Cutter wheel post 21 has cutter wheel base abutting portion 22, cutter wheel receiving portion 23 and threaded portion 24 of slightly lesser diameter at the end thereof. Cutter wheel receiving portion 23 is of a length slightly greater than the thickness of the cutter wheel 25. The lesser diameter of the threaded portion 24 of the post 21 limits the inward motion of washer 26 and nut 27 which rotatably position the cutter wheel 25 thereon. The cutter wheel 25 has cutting edge 25a, recessed portion 25b and base portion 25C. Front can guide 28 has base portion 29 thereof lixed to the face of frame 10 and opening 36 (Figs. 5 and 6) formed therein congruent to frame slot 18.

Means are furnished on the face of the frame 10 opposite that carrying the cutter wheel 25 for providing a ful crum and cam assembly positioned relative the frame slot 18. In the embodiment of the invention illustrated in the drawings, these means are shown as a separate cam plate 31, riveted, welded or otherwise lixedly attached to said face of the frame 10. Cam plate 31, in its preferred form, extends essentially congruent with the front portion of the frame 10 to a position rearward of the frame slot 18 and then tapers centrally as at 31a to end shortly rearwardly of the opening 16 from which the rear can guide was formed. The cam plate 31 thus covers the opening 16 should be formed in the provision of rear can guide 15.

Opening 32 is formed in the lower central portion of the cam plate 31. Essentially horizontal cam shelf 33 is formed in the portion of opening 32 rearward of the frame slot 18. Shelf 33 is preferably positioned below the top of slot 18 a distance slightly greater than the radius of drive shaft flange portion 41 to be later described. The radial surface 34 of the cam plate 31 extending clockwise from shelf 33 (facing the carn plate 31 side of the frame) is formed at a radial distance from the center of slot 1S so as at all times to be outside the sweep of the handle pin 56 (to be later described). Cam surface 34 is formed normal to the `surfaces of plate 31 and frame 1li. Radial rise cam surface 35 commencing at a point approximately 40 of arc clockwise from shelf 33 and continuing for approximately 40 therefrom is of such contour as to always be within the sweep of handle pin 56 when a can is engaged between the feed wheel and cutter wheel before the puncturing of the end thereof. The remainder of the radial surface 34a, after radial rise cam surface 35 up to lateral rise cam surface 36, is of such contour as to always be outside the sweep of the handle pin 56 in the operation of the can opener. The lateral rise cam surface 36 may be formed, if desired, by forcing a tab of the cam plate 31 into frame opening 17.

The handle-feed wheel assembly, which comprises in assembled relationship a single operative, rotatable construction extending through the frame slot 18, will now be described. Handle 37, having knob 38 thereon, is ixedly attached or welded at its end to the center of handle thrust disc 3?. Feed wheel drive shaft 46 is ilxedly attached to the opposite face of the handle thrust disc 39 and is rotatable therewith. The feed wheel drive shaft 43 has two parts, a flange portion 41 having a thickness equal to the combined thickness of the frame 1@ and cam plate 31 surrounding the slot 18 and a threaded portion 42 of lesser diameter. The diameter of the flange portion 41 of the feed wheel drive shaft 4i) is slightly less than the width of the slot 18 in the frame 16. The length of the threaded portion 42 of the drive shaft 40 is preferably at least equal to the combined thicknesses of the front can guide base 29, the feed wheel thrust disc 43, and feed wheel 44. Feed wheel 44 has toothed portion 44a and base portion 44b of lesser diameter. Feed wheel thrust disc 43 has a diameter greater than the width of slot 18. Feed wheel drive shaft shims 45 are of slightly greater thickness than the front can guide base 29 whereby to give a minimum desired clearance to handle thrust disc 39 relative cam plate 31 and feed wheel thrust disc 43 relative front can guide base 2.9 whereby to permit rotation of the two thrust discs relative the frame without excess friction therebetween. The diameters of the handle thrust disc 39 and the feed wheel thrust disc 43 are such that good perpendicular alignment of the axis of the feed wheel with the frame exists throughout the life of the can opener. Shims 4S permit, in assembly or repair, proper spacing between the thrust discs and the combined stackup of the three parts therebetween. The proper perpendicular alignment of the feed wheel axis to the face of the frame depends on precise spacing of the two thrust discs. Feed wheel shims 46 may be varied in thickness to properly position the outer face of feed wheel 44 relative the inner face of cutting wheel edge a in lateral spacing in assembly or repair. It will be observed that upon tightening feed wheel 44 upon feed wheel drive shaft threaded portion 42, a handle-feed wheel assembly is provided which is able to rotate with the feed wheel drive shaft 40 extending through the slot 13 in the frame and the opening 32 in the cam plate 31 and, as well, move vertically upwardly and downwardly in slot 18 of the frame 10 due to the fact that the feed wheel drive shaft flange portion 41 extends through the slot 18 and is of lesser diameter than the width of the slot 18 and shims 45 prevent excessivevfrictional engagement of the thrust discs with the frame and cam plate. The top and bottom portions of the slot 18 are rounded in arcs equivalent to arcs of circles of slightly greater diameter than the diameter of the drive shaft flange portion 41. The diameter of the feed wheel thrust disc 43 is preferably su'ostantially greater than the width of the slot 1S and the diameter of the handle thrust disc is preferably substantially greater' than twice the distance from the center of slot 13 to the periphery of the opening 32 along the line of the cam shelf 33 extended (the greatest radius of the opening 32).

Means are provided fixed relative the frame 10 for continuously urging the handle-feed wheel assembly toward its upmost position relative the fixed cutter wheel 25. ln the preferred form, as shown in the drawings, this means comprises feed wheel supporting lever plate 47 which is pivotally mounted preferably essentially centrally thereof as at 48 on the cutter wheel face of the frame 1t). Lever 47 comprises essentially an elongated bar or plate pivoted rearwardly of the cutter wheel 25 on frame 10 with forward arm 49 thereof positioned below the handlefeed wheel assembly and ortset outwardly to clear the front can guide base 29 and feed wheel thrust disc 43 which are mounted on the face of the frame 1h. Arcuate cutout portion S0 (Figs. 5 and 6) is formed in the upper edge of the outwardly offset arm to receive the base portion 44b of the feed wheel 44 and is formed as a circular arc having a slightly greater radius of curvature. The thickness of the lever 47 is less than that of the feed wheel base 4411. The cutout portion 50 acts as a radial bearing to take the downward thrust on the feed wheel 44 during the can cutting process. The nearness of this bearing to the lateral plane of the face of the feed wheel materially reduces the force or effort required to effect rotation of the feed wheel for feeding the can relative the cutting edge of the cutter wheel. Outwardly offset arm 49 also has can positioning flange Sl at the base thereof to position a can properly relative the cutter and feed wheels. The rearward arm of lever 47 has spring wire receiving portion or tab 52 formed adjacent the end thereof. Coiled resilient means or wire spring 53 engages with one of its ends tab 52 and with the other spring flange 13 through its opening 14. Spring 53 operates to constantly exert force through the lever 47 on the handle-feed wheel assembly to urge it upwardly toward the top of slot 1S. The coil form of spring S3 is preferred in that it provides a minimum differential between compressive forces required at any of the spring positions. Notch 54 at the front po-rtion of outwardly offset arm 49 of the lever 47 operates to engage the lower edge of the front can guide 23 at a level just short of that where the feed wheel drive shaft llange portion 41 would be forced against the top of slot 18 and opening 32 of cam plate 31. Thus the handle-feed wheel assembly may be rotated easily in its uprnost position. The distance between the bottom of the cutout portion 50 of lever arm 49 to the top of slot 1S when notch 54 is engaged is, however, only slightly greater than the diameter of drive shaft flange portion 41 thereby permitting very little free vertical play or motion of the handle-feed wheel assembly.

Means are provided cooperating between the handle thrust disc 39 and the cam assembly provided by cam plate 31 whereby (l) to fulcrum the handle-feed wheel assembly downwardly from an upper position in the slot 18 (as when there is no can inserted in the opener) when the handle 37 is rotated in one direction (counterclockwise in Fig. l) and (2) to cam the handle-feed wheel assembly upwardly from a lower position in the slot 18 (after the insertion of a can rim between the cutter wheel and feed wheel) by rotation of the handle 37 in the other direction. Such means will now be described. Circular opening 55 is formed in the handle thrust disc 39 preferably as closely as possible to the center thereof. The center of opening 55 is preferably formed in disc 39 so the line of the handle and a line formed by the center of the disc and the center of opening 55 meet in a slightly obtuse angle, the opening 53 being rearward of the handle when the handle is in a downward position. The handle may be positioned 180 from the position shown or in any other preselected position. Large diameter portion 56a of handle pin 56 is circular in form and of only slightly less diameter than the diameter of circular opening 55 whereby to move easily therethrough. The length of the pin portion 56u is slightly greater than the combined thicknesses of cam plate 31 and handle thrust disc 39. Spring receiving portion 56h of the pin 56 is of lesser diameter than portion 56a, extends outwardly therefrom and is received in angled frame 57 having opening 58 therein. Opening 53 is slightly greater in diameter than pin portion 56h. The length of the spring receiving portion 56] is preferably slightly greater than the distance from the outer face of the handle thrust disc 39 to the outer face of the frame 57. Spring 59, cooperating between the inner face of the frame 57 and the outer face of the cam portion 56a tends to urge the pin 56 inwardly toward the cam plate 31.

As previously mentioned, the radial surface 34 of the cam plate 31 is formed at a radial distance from the center of slot 18 so as at all times to be outside the sweep of the handle pin S6. The radial rise cam surface 3S is of such contour as to always be within the sweep of handle pin 56 when a can is engaged between the feed wheel and the cutter wheel before the puncturing of the end thereof. The remainder of the radial surface 34a is of such contour as to always be outside of the sweep of the handle pin 56 in any stages of the operation of the can opener. Additionally, it should be noted that, once the end of the can is punctured, the pin 56 will clear all of the surfaces 34, 35 and 34a as the handle is rotated.

In the use of the can opener with conventional kitchentype cans for home use, the supporting plate spring 53 is preferably selected so that the supporting plate 47 urges the feed wheel constantly upwardly toward the cutter wheel by a force of approximately 50 pounds. This force is nearly adequate, but not quite so, for piercing the end of a can. Therefore, relatively little additional upwardly exerted mechanical force is required to supplement that afforded by the feed wheel supporting plate spring 53 to effect the piercing of the end of the can. After such initial piercing, with the handle cam action aiding the spring force, the fifty pounds force exerted by the spring 53 is sufficient to force the can additionally upwardly whereby to keep the rim or bead of the can firmly seated upwardly in the grooved portion 25h of the overlying cutter wheel 25 during the remainder of the cutting process. The urging of the spring 53 also forces the can engaging teeth of the feed wheel to penetrate the under edge of the can rim or bead to assure adequate traction of the teeth of the feed wheel 44 with the rim or bead of the can. The additional upward motion after the initial piercing of the end of the can caused by the force exerted by the spring 53 also raises the feed wheel sufficiently so as to permit the cam engaging portion 56a of the pin 56 to radially clear the highest point of the radial rise cam surface 35 in subsequent rotation of the handle assembly until another can is inserted and engaged before piercing in the can opener.

The rear can guide 15', preferably formed integrally with the frame or body plate 10, prevents the can from tilting in the can opener as the end is being sheared from the can. The front can guide 28 prevents the can from canting away from the cutter wheel and maintains the can, in relation to the point of shearing engagement with Athe cutter wheel, at the most advantageous position for the most efficient and easiest shearing of the end from the can. The front can guide base 29 provides a hardened wearing surface against which the hardened feed wheel thrust disc 43 bears. This is minimize wear that otherwise would permit harmful, premature and undesirable increase in the lateral spacing between the cutter wheel and feed wheel.

lFrom the description of the single action mechanism which follows it will be seen that such mechanism comprises a relatively simple and fool-proof arrangement. In this arrangement the can opener handle is fulcrumed, through the handle thrust disc 39 and pin 56, at a selected angular position relative the frame 10 upon counterclockwise rotation thereof to provide a lever for moving the feed wheel downwardly, against the tension of the feed wheel supporting lever spring 53, thereby separating the feed wheel from the overlying cutter wheel to permit engagement of a can with, or removal of a can from, the opener. If the feed wheel is urged upwardly toward the cutter wheel by a force of fty pounds and an eight to one leverage is provided in the handlehandle thrust disc lever system, a force of not over thirteen pounds is required on the handle knob for lowering the feed wheel away from the cutter wheel.

In operation, if the handle is not already in the position in which it would be upon completion of the operation of opening a can (in which position it would normally be left by a user), the handle is rst rotated counterclockwise as far as possible. The result of this extreme counterclockwise rotation is the assumption of the position shown in full lines in Fig. l wherein the handle pawl or pin 56 larger diameter portion 56a abuts the cam shelf 33 of the opening 32 in the cam plate 31. The handle pin 56 thus becomes the fulcrum in a lever system extending from the pin 56 to the center of the drive shaft 40 as it engages handle 37 and then at a slightly obtuse angle down the handle 37. As force is exerted on the lower end of the handle, the lower end of the handle rotates further in a counterclockwise direction around the fulcrum afforded by the pin 56 at the upper end of the handle to arrive at the position shown in dotted lines in Figs. l and 2. The motion of the handle 37 from the full line position of Fig. l to the dotted line position of Fig. 1 results in lowering of the axis of rotation of the upper end of the handle and, thus, separation of the feed wheel 44 from the cutter wheel 25. VThe force exerted by the operator or the user of the can opener must be sufficient to overcome the force exerted upwardly on the feed wheel base portion 44b by the lever 47. With a lever ratio of eight to one, one-eighth of the spring force (plus friction) must be overcome by the operator. While in such lowered position, the can is inserted in the can opener with its upper end held upwardly against the periphery of the cutter wheel. Release of force by the operator on the handle then permits the spring 53, operating through lever 47, to urge the feed Wheel 44 upwardly so that it engages firmly the under edge of the rim or bead of the can and holds the can top against the cutter wheel with the force of the spring 53. As previously mentioned, this force is preferably slightly less than that necessary for piercing the end of the can. Therefore, the operator then rotates the handle 37 clockwise to bring the enlarged portion 56a of the pin 56 in contact with the radial rise carn surface 35 of the cam plate. Continued rotation of the handle causes an upward force to be exerted upon the entire handle-feed wheel assembly and the additional force thus applied to the underside of the rim of the can causes puncturing of the end thereof. As previously described, after the initial puncturing of the can, the force exerted on the feed wheel 44 by the spring 53 through the lever 47 is sufficient to maintain the feed wheel in its uppermost position with the top edge of the can rim or bead seated against the recessed portion ZSb of the cutter wheel. Thus, after the puncturing of a can and the subsequent additional rise of the feed wheel 44, the pin 56 will radially clear all points of the radial surface of the cam plate 31 until another can is engaged in the can opener to be pierced.

After the end of the can has been pierced and the hande 37 has been rotated approximately 90 further clockwise, the enlarged portion 56a of the pin 56 engages the lateral rise cam surface 36 of the cam plate 31. Further rotation of the handle 37 causes the pin 56 to ride up the lateral rise cam surface 36 until it clears the upper edge of the opening 32 in the cam plate 31. Continued rotation of the handle 37 will bring the pin 56 past the cam shelf 33 where the tension of the handle pin spring 59 will force the pin 56 inwardly until it seats against the frame within cam plate opening 32 of the can opener. As clockwise rotation of the haudle is continued, to effect shearing of the end of the can by the cutter wheel, the handle pin 56 will continue to ride in end engagement with the lateral surfaces of the frame 10 in opening 32 and cam plate 31.

At any rotational point, the handle 37 may be stopped and the direction of rotation reversed to once again engage the pin 56 with the cam shelf 33 to form a fulcrum for the lever system created by pin 56, drive shaft 40 and handle 37. Not more than one turn of handle 37 is required to bring pin 56 into such fulcrum position. If, when counterclockwise rotation of the handle 37 is commenced, the inner end of the handle pin 56 is in engagement with the frame 10 which is exposed by opening 32, said handle pin will be in the proper plane for engaging and fulcruming against the cam shelf 33. After pin 56 fulcrums against the cam shelf 33, further counterclockwise rotation of the handle 37 effects lowering or separation of the feed wheel 44 from the overlying cutter wheel 25 to permit insertion or removal of the can from the can opener. on the handle then permits the tension of the feed wheel supporting lever spring 53 to again move the feed wheel 44 upwardly to its uppermost position. If, however, pin 56 is on cam plate 31, counterclockwise rotation of handle 37 will cause it to ride down lateral rise cam surface 36, spring 59 urging the pin inwardly into `engagement therewith to contact frame 10.

Downward movement of the feed wheel 44 is positively limited by engagement of the feed wheel drive shaft portion 41 with the lower end of the vertical elliptical slot of the frame through which the feed wheel drive shaft 40 extends. Upward movement of the feed wheel is limited by abutment of the notch 54 at the front end of lever 47 with the front can guide 28. The notch 54 of the feed wheel supporting lever 47 engages the front can guide 2S only when a can is not engaged in the can opener. The notch 54 at the forward end of the feed wheel lever 47 engages the lower end of the outwardly formed portion of the front can guide 28 a few thousandths of an inch before the feed wheel drive shaft portion 41 would otherwise arrive at the upper end of the vertical elliptical slot 18 of the fra-me 1li. This engagement prevents the force of the feed wheel supporting plate spring S3 from urging the feed wheel drive shaft portion 41 upwardly against the top of the slot 1S. Such engagement permits easy rotation of the handle when a can is not engaged in the can opener. However, tension of the handle pin spring S9, urging the inner end of the handle pin 59 into frictional engagement with the cam plate 31 or frame 10, is adequate to maintain the handle in any position to which it is turned when a can is not engaged in the can opener.

The passing of the side seam of a can depends on a slight vertical separation of the feed wheel from the cutter wheel. This slight separation, against the tension of the feed wheel supporting lever spring 53, is somewhat facilitated by the fact that the feed wheel radial bearing is close to the lateral plane of the feed wheel Release of counterclockwise force supporting plate spring 53 (thus assuring freeness of operation), together with the fact that rotation of the aligning parts (handle thrust disc 39 and feed wheel thrust disc 43) concurrent with the slight vertical movement of these parts facilitates such slight vertical movement.

From the foregoing it will be seen that this invention is one well adapted to attain all of the ends and objects hereinabove set forth, together with other advantages which are obvious and which are inherent to the structure.

lt will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations. This is contemplated by and is within the scope of the claims.

As many possible embodiments may be made of the invention without departing from the scope thereof, it is to be understood that all matter hereinabove set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

Having thus described my invention, I claim:

l. A single action can opener comprising a frame, a cutter wheel rotatably mounted in a fixed position on one side of said frame, a slot through said frame one end thereof being positioned closely adjacent said cutter wheel, a rotatable shaft received in and extending through said slot, a feed wheel assembly positioned on one end of said shaft on the side of the frame carrying said cutter wheel, a handle assembly positioned on the other end of said shaft on the opposite side of the frame from the feed and cutter wheels, said feed wheel assembly, shaft and handle assembly comprising together a unitary handlefeed wheel assembly movable in said slot relative said frame and the position of the cutter wheel thereon, means on said frame for continually urging the handle-feed wheel assembly toward the end of the slot nearest the cutter wheel, a fulcrum surface and a radial cam surface formed in the face of the frame opposite that carrying the cutter wheel adjacent the slot therethrough, and means cooperating with the handle assembly to engage the fulcrum surface to move the handle-feed wheel assembly from a position adjacent to a position away from the cutter wheel and to engage the radial cam surface to move the handlefeed wheel assembly from a position away from said cutter wheel to a position adjacent thereto.

2. Apparatus as in claim l wherein said urging means for said handle-feed wheel assembly comprises a lever pivotally mounted on the frame, one arm of the lever contacting the handle-feed wheel assembly and the other arm connected to resilient means tending to rotate the lever around its pivot.

3. Apparatus as in claim 2 wherein the rotational axis of the handle-feed wheel assembly is between the contacting lever arm and the cutter wheel.

4. Apparatus as in claim l wherein the means engaging the fulcrum surface and radial cam surface engages the former in one direction of rotation of the handle and the latter in the other direction of rotation of said handle.

5. Apparatus as in claim 1 including means carried by said frame to limit the closeness of approach of the handle-feed wheel assembly in the slot to the cutter wheel and the upper boundary of the slot whereby there is no binding of the shaft in the slot.

6. Apparatus as in claim 1 wherein said handle assembly comprises a handle arm xed to the shaft and a handle thrust disc having a greater radius than the distance from the center of the shaft at any point in the slot to the periphery of the fulcrum surface and radial cam surface, said handle thrust disc xed to the shaft and handle and rotatable therewith, the means cooperating with the handle assembly comprising a pin extending through the handle thrust disc radially displaced from the axis of rotation thereof, and resilient and yieldable means forcing the pin into engagement with the face of the frame, the pin engageable on rotation of the handle in one direction with the fulcrum surface and in the other direction with the radial cam surface when the handle-feed wheel assembly is at certain positions in the slot.

7. Apparatus as in claim 1 wherein said fulcrum surface and radial cam surface are recessed in the face of the frame.

8. A single action can opener comprising a frame, a cutter wheel rotatably mounted in a xed position on one side of said frame, a slot through said frame, one end thereof being positioned closely adjacent said cutter wheel, a rotatable shaft received in and extending through said slot, a feed wheel assembly positioned on one end of said shaft on the side of the frame carrying said cutter wheel, a handle assembly positioned on the other end of the shaft on the opposite side of the frame from the feed and cutter wheel, said feed wheel assembly, shaft and handle assembly comprising together a unitary handlefeed wheel assembly movable in said slot relative said frame and the position of the cutter wheel thereon, means on said frame for continually urging the handle-feed wheel assembly toward the end of the slot nearest the cutter wheel, a recessed portion formed in the face of the frame opposite that carrying the cutter wheel, said recessed portion circumferential to the slot, the boundary of at least part of said recessed portion spaced radially away from said slot to form a camming surface, one radial extremity of said camming surface formed as a shelf extending substantially normal to said camming surface and communicating between said recessed portion and the face of the frame, the other radial extremity of said camming surface formed as a ramp extending from the recessed portion to the surface of the frame, and means cooperating with the handle assembly to engage the shelf to move the handle-feed wheel assembly from a position adjacent to a position away from the cutter wheel and to engage the camming surface to move the handle-feed wheel assembly from a position away from said cutter wheel to a position adjacent thereto.

9. A single action can opener comprising a frame, a cutter wheel rotatably mounted in a xed position on one side of said frame, a slot through said frame, one end thereof being positioned closely adiacent said cutter wheel, a cam plate fixed to the face of the frame not carrying the cutter wheel, an opening in said cam plate surrounding said slot, the boundary of at least part of said opening spaced radially away from said slot to form a camming surface, one radial extremity of said camming surface formed as a shelf extending substantially normal to said camming surface and communicating between the outer face of the cam plate and the face of the frame, the other radial extremity of said camming surface formed as a ramp extending from the face of the frame to the surface of the cam plate.Y a rotatable shaft received in and extending through said slot and opening, a feed wheel assembly positioned on one end of said shaft on the side of the frame carrying said cutter wheel, a handle assembly poistioned on the other end f the shaft on the opposite side of the frame from the feed and cutter wheels, said feed wheel assembly, shaft and handle assembly comprising together a unitary handle-feed wheel assembly movable in said slot relative said frame and the position of the cutter wheel thereon, means on said frame for continually urging the handle-feed wheel assembly toward the end of the slot nearest the cutter wheel, and means cooperating with the handle assembly to engage the shelf to move the handle-feed wheel assembly from a position adjacent to a position away from the cutter wheel and to engage the camming surface to move the handle-feed wheel assembly from a position away from said cutter wheel to a position adjacent thereto.

l0. A single action can opener comprising a can opener body, a cutter wheel rotatably fixed to one side of said body, a feed wheel normally disposed in operative can cutting relationship with said cutter wheel, a feed wheel drive shaft supported on said body and carrying said feed wheel, said drive shaft being movable on said body in a direction to vertically separate said feed wheel from said cutter wheel, yieldable resilient means continually urging said drive shaft into the normal position for said feed wheel, and cooperating pawl and fulcrum means connected respectively with said shaft and body and operable upon rotation of said shaft in a predetermined direction to cause said shaft to move in a direction to vertically separate said feed wheel from said cutter wheel.

11. A single action can opener as in claim 10 wherein said fulcrum means is provided with a portion operable when said shaft is rotated in the other direction to exert a force to positively return said shaft to said normal position for the feed wheel upon failure of said shaft to reach said position under the influence of said yieldable resilient means alone.

12. A single action can opener comprising a can opener frame, a cutter wheel rotatably mounted in a fixed position on One side of said frame, an elongate aperture through said frame having one end closely adjacent said cutter wheel, a rotatable shaft extending through said aperture, a feed wheel assembly, including a thrust disk encircling said shaft of a diameter greater than the width of the slot and poistioned between the feed Wheel and the frame mounted on and fixed relative to one end of the shaft on the same side of said body as said cutter wheel, a handle assembly including a thrust disk next the frame to rotate with said handle mounted on the other end of said shaft and on the opposite side of said body from the cutter and feed wheels, said feed wheel, shaft and handle assembly forming together a unitary handle-feed wheel assembly movable in said slot toward and away from said cutter wheel, yieldable resilient means associated with said handle-feed wheel assembly normally urging said handle-feed wheel assembly toward the end of said aperture nearest the cutter wheel, and cooperating r pawl and fulcrum means connecte-d respectively with said handle-feed wheel assembly and body and operable upon rotation of said shaft in one direction to cause said handlefeed wheel assembly to move in said aperture in a direction to vertically separate said feed Wheel from said cutter wheel a distance sufcient to permit insertion of the can flange therebetween, the handle thrust disk having a greater radius than the distance from the center of the shaft to the periphery of the pawl and fulcrum means and means including at least a portion of the shaft separating the handle and feed wheel thrust disks a distance at least slightly greater than the width of the frame between them whereby the handle-feed wheel assembly rotates relatively frictionlessly relative the frame.

References Cited in the le of this patent UNITED STATES PATENTS