US3821850A

US3821850A - Can opener

Info

Publication number: US3821850A
Application number: US00317066A
Authority: US
Inventors: R Kowalyk
Original assignee: Blum Inc
Current assignee: Blum Inc
Priority date: 1972-12-20
Filing date: 1972-12-20
Publication date: 1974-07-02
Anticipated expiration: 1991-07-02

Abstract

Mechanism for rapid opening of cans for restaurant and like large-volume food preparations. Cans opened by relative movement between can-supporting platform carrying stripper plate and a pointed circular guillotine cutting blade having outward beveled or tapered edge to swage the residual panel of the severed lid against inside diameter of can wall, straighten dents in wall of can adjacent crimped rim of lid panel and swell upper wall of can to permit the stripping of opened can from blade. Cams in platform permit unopened cans to displace opened cans and to center the displacing can for opening. Severed lids may be automatically removed or kept in place on contents for subsequent manual removal.

Description

United States Patent [191 Kowalyk [111 3,821,850 1 July 2,1974

[ CAN OPENER [75] Inventor: Richard J. Kowalyk, Lyndhurst,

Ohio

[73] Assignee: Blum Incorporated, Cleveland, Ohio [22] Filed: Dec. 20, 1972 [21] Appl. No.: 317,066

[52] US. Cl 30/4 A, 30/64, 30/55 [51 Int. Cl B67b 7/38 [58] Field of Search 30/5 A, 5.5, 6.1, 6.4, 30/8, 10, 16

[56] References Cited UNITED STATES PATENTS 691,867 1/1902 Law 30/5.5 1,115,159 10/1914 Bauer 1,317,001 9/1919 Clymer 1,789,729 1/1931 Coyle..... 2,712,176 7/1955 Miller 3,739,472 6/1973 Peres 30/64 Primary ExaminerAl Lawrence Smith Assistant ExaminerGary L. Smith Attorney, Agent, or Firm-Ely & Golrick [5 7] ABSTRACT Mechanism for rapid opening of cans for restaurant and like large-volume food preparations. Cans opened by relative movement between can-supporting platform carrying stripper plate and a pointed circular guillotine cutting blade having outward beveled or tapered edge to swage the residual panel of the severed lid against inside diameter of can wall, straighten dents in wall of can adjacent crimped rim of lid panel and swell upper wall of can to permit the stripping of opened can from blade. Cams in platform permit unopened cans to displace opened cans and to center the displacing can for opening. Severed lids may be automatically removed or kept in place on contents for subsequent manual removal.

12 Claims, 19 Drawing Figures PAFENTEML 2 mm SHEEI 7 BF 7 fin I CAN OPENER This invention relates to a power-operated machine for opening cans, particularly the conventional large cans of food for restaurants, commissaries, and similar establishments and institutions engaged in the preparation and serving of food in large volume.

In the operation of kitchens of restaurants, hotel and motel dining rooms, the dining rooms of schools, hospitals, commissaries, and like institutions, for example, a substantial volume of the food is supplied in large, standard sized cans. The equipment heretofore available for opening such cans has required a substantial amount of the time of the available and increasingly costly labor in the kitchen, and if operated by hand (or foot) required substantial physical effort and/or was very slow, in comparison with the rate at which cans can be opened by machines made according to this invention.

It is accordingly an object of this invention to provide a machine which will open the cans quickly with little physical effort. In very large volume operations in which a large number of cans may be required to be opened substantially continuously during extended periods, a machine made according to this invention may be operated by two persons, one loading unopened cans at the machine and one unloading opened cans. In lower-volume operations or at periods when only one or a few cans need to be opened, the machine is conveniently operated by one person.

Another disadvantage of many available prior art machines was that they required that the cans be undented. An advantage of a machine made according to this invention is that it is operative to open cans which, in normal shipping and handling in storage, have received dents either in the wall of the can adjacent the crimped rim sealing the end panel or closure or in that rim, which dents are insufficient to impair the contents but which, unless discarded, heretofore required that they be opened slowly and laboriously with conventional domestic openers which cut the top panel by following the sealing head.

Another object and advantage of this invention is that the sharp and dangerous cut edge or residual panel" normally left in the top closure of the cans is swaged to a safe position against the inside diameter of the can wall.

A further advantage of this invention is that it may be modified by providing means for automatically removing the severed end closure or lid" or the severed lid may be left inplace on the contents for later manual removal. In either case, the lid is severed without leaving metal cuttings in the contents.

Still-other objects and advantages of this invention, including the manner in which it meets health regulations, will be apparent from the following specification, claims, and drawings, in which:

FIG. 1 is a perspective view of a machine made according to this invention, and equipped with automatic lid-removing means; the view, taken from the loading side, shows the machine provided with the hood or cover, usually wholly or partly transparent, preferably employed during operation of the machine.

FIG. 2 is an enlarged fragmentary perspective of the machine shown in FIG. 1, but with the hood removed and the can platform raised.

FIG. 3 is a perspective of the machine shown in FIG. 1, but taken from the unloading side, and with the hood removed.

FIG. 4 is an elevation of the machine shown in-FIG. 1, taken from the loading side and with the hood removed.

FIG. 5 is a detail perspective of the platform shown in FIG. 6.

FIG. 6 is a detailed plan view of the platform taken from the plane indicated by the line 6-'-6 in FIG. 2.

FIG. 7 is a fragmentary detail cross-section taken along the line 77 of FIG. 6.

FIG. 8 is a development of the outside of a cutting point of the circular blade shown in FIGS. 1 to 4.

FIG. 9 is a fragmentary detail section showing a can, the stripper plate, and the cutting point as it is about to pierce the sealed top closing panel.

FIG. 10 is a view similar to FIG. 9, but showing the removal of the can from the blade and the swaged residual panel.

FIG. 11 is a fragmentary detail of the closure panel partly severed by the blade.

FIG. 12 is a detail exploded view showing the inside of the blade and the severed lid.

FIG. 13 is a detailed elevation taken along the line l313 of FIG. 12 and showing a fragmentary section of the severed lid taken along the line 1313 of FIG. 14.

FIG. 14 is a perspective of a lid severed by the blade of the machine shown in FIGS. 1 to 4.

FIG. 15 is a perspective of a machine made according to thisinvention, but with a lid-replacing means rather than a lid-removing means.

FIG. 16 is a detailed perspective of the portion enclosed within the hood of the machine shown in FIG. 15.

FIG. 17 is a detailed elevation, partly in section, of the portion shown in FIG. 16 and partly in phantom to show its operation.

FIG. 18 is a fragmentary perspective similar to FIG. 16, but showing another form of lid-replacing means.

FIG. 19 is a detailed elevation, partly in section, of the portion shown in FIG. 18 and partly in phantom to show its operation.

Referring to the embodiment of this invention as disclosed in the machine illustrated in FIGS. 1 to 4, the machine is composed of a base plate 10, in this instance supported by legs 11 permitting the machine to be installed according to the kitchen lay-out in a freestanding position in the kitchen or adjacent to suitable counter or conveyor from which the unopened cans may be loaded on a can-platform 20 and a similar counter or conveyor onto which the opened cansmay be unloaded from the platform 20. The base plate 10, in this instance, carries on its undersurface a doubleacting hydraulic or pneumatic cylinder mechanism 12 which raises and lowers through a suitable opening the shaft 13 connected to the platform 20. The cylinder mechanism 12 is driven from a suitable fluid power source (not shown) and the cycle of a reciprocation of the shaft 13 is commenced by an operators pressing any one of the three buttons 14a, 14b, or 14c connected by parallel control lines to an internal cycling valve in the mechanism 12.

The purpose of providing three or more control buttons 14 located as shown at corners of the base plate is to allow the machine to be actuated by an operators pressing either of the buttons 14a or 14b as he stands in front of the machine to load the machine while a second operator stands at the rear of the machine to unload it. If but one operator is employed to load and unload the machine, he will usually stand at the side of the machine to place an unopened can onto the platform 20 with one hand and move a displaced opened can onto a suitable counter or conveyor (indicated in phantom in FIG. 1) with the other hand; in this case the machine may be cycled by pressing either the bottom 14b or 140, depending upon which is most convenient to the operator due to the kitchen layout and- /or whether the operator is rightor left-handed. Alternatively, of course, the buttons 14 may be supplemented or replaced by suitable foot or knee operated controls; also means other than the cylinder means 12 may be employed to reciprocatethe shaft 13, such as for example, a sufficiently powerful electric motor operating a reciprocating linkage through a clutch limiting the revolution or revolutions through which the motor drives the linkage for one reciprocation of the shaft 12.

Referring also to FIGS. 5-7 for details, the platform 20 carries on its under surface a cam plate 21 pivoted at the loading end of the platform by means of the bosses 22 and pin 23 and normally pressed upwardly by a spring carried by a coupling 16 connecting the shaft 13 to the underside of the platform 20. The cam plate 21 carries at its corner opposite its pivoted end a pair of

centering stops

24 and 25, a central centering cam 26 and a lateral trip cam 27, the latter having a greater height and length above the cam plate 21, as best shown in FIG. 7. The stops 25 and earns 26 and 27 normally extend upwardly through suitable openings in the platform to be engaged by a can C, as explained below. The lateral cam 27, by means of the rod 28, carries an outwardly extending knob 29; this permits manual depression of the cam plate 21 against the bias of the spring 15 in case it should be necessary to back off a can C over the

cam

26 and 27 onto the entrance portion of the platform 20 as well as when it is necessary to push the last can of a series to be opened over the stops 24 and onto an unloading counteror conveyor.

By means of vertical corner posts 31, a stripper plate 30 is supported above the platform 20 at a height just sufficient to clear the top of a can C centered at the opening position on the platform 20. The posts 31 carry pairs of lateral horizontal guide bars 32 which both serve to guide a can C into its centered position on the platform 20 and to hold it from lateral displacement after it is engaged against the

stops

24 and 25. The stripper plate-30 is provided with a central opening 34 permitting it to be raised above the cylindrical outside of the cutting blade 50 and also with a pair of lateral guide bushings 35; these bushings slidably mount the stripper plate 30 on the support posts 41 of the cutter head plate to insure, in view of the limited tolerance evident in FIGS. 4, 9, and 10, that the opening 34 clears the blade and also to resist twisting and displacement of the platform 20 as it is reciprocated by the shaft 13.

The cutter head plate 40 is provided with a central opening 42 through which a served can lid is accessible or may be removed. On the underside of the cutter head plate 40 is mounted the cylindrical cutter blade 50. In this particular embodiment the blade 50 is comprised of a plurality of segments 5l'welded or otherwise made unitary with a blade ring 52 bolted tothe head plate 40 to allow removal of the blade 50 for sharpening and maintenance; this arrangement also allows replacement of the blade 50 by a smaller or different blade which, as part of a suitable adapter kit, may be used to adapt the machine to different size cans which may be smaller in diameter or non-cylindrical. Each blade segment 51 is provided with a substantially centered piercing point 53 which commences the cuts in the can lid CL, as indicated by the cut edgesCE inFlG. 1 1. To avoid flipping or excessive bending of the lid CL as it is cut by the 'blade 50, the piercing points 53 should contact the lid at substantially equally spaced points around the lid. In theory, it might seem that a blade 50 should be operative if it were provided with one or a pair of diametrically opposite piercing points whose cutting edges would advance their cuts equally around the lid as the can is moved against the blade. In practice, however, such a blade with a single piercing point or an opposed pair of points has two serious faults: (i) The drag of the cutting edges 54 on the can lid (unless the blade edges 54a and 54b are very steep) tends to bend the lid into the container and/or flip it as the" cut is being completed. (ii) If the edges 54 are very steep to avoid this fault, the stroke of the blade into the can has to be very long and, due to the swaging action to be described below, the stroke either has to be very slow or requiresthat a sudden and excessive pressure be applied to the can body by the shaft 13 which raises the platform 20 and, thus, the can C and its lid CL against the blade 50. If the blade 50 is provided with a substantial number of equally spaced piercing points, in theory the cutting stroke could be short and rapid but, in practice, the pressure necessary to be exerted through the shaft 13 increases to an excessive degree and cans whose lids are distorted from a plane by dents in the side walls or on the rim of the lid panel may not be consistently opened completely. Provided other required conditions and functions to be obtained by a cutting blade 50 according to this invention are achieved, it has been discovered that a cutting blade 50 with four substantially equally spaced piercing points 53 is optimal'by far; blades with three or five equally spaced piercing points may be operational, but less reliably so, apparently due to variations in the quality and stiffness of the tinplate in commercial can lids.

In addition to the number and spacing of piercing points on a blade 50 being relatively critical, it has also been found that range of angles of the cutting edges 54 to the plane of the lid (indicated by the line CL in FIG. 8) can also be highly critical. The preferred range is between 35 and 40 and thus an included angle of 1 10 between the edges 54, except where, in a blade comprised of spaced segments, as shown in FIGS. 1 to 4 and 12, to permit lid removal, the segment 51 may be provided with a leading edge 54a and a trailing edge 54b, whereby the angle a for the leading edge may range between 30-40 for the leading edge 54a and the angle b is between 3545 for the trailing edge 54b. Can lid severing operation.

The operation of the machine as described thus far isas follows:

With an unopened can placed on the forward portion of the platform 20, an operator pushes it over the

cams

26 and 27 between the bars 32. The cam plate 21being thus depressed by the weight of the can C on the

cams

26 and 27, the

stops

24 and 25 drop below the platform so that a preceding can which has been centered against them while it was being opened is thereby pushed ahead onto a suitable unloading counter or conveyor by the unopened can. As the sides of the opened can pass beyond the

stops

24 and 25 while still being pushed by the unopened can, the side of the unopened can clears the lateral cam 27. The stops 24 and 25 then rise above the surface of the platform 20 to insure that they will be engaged by the lower rim of the unopened can as it clears the central cam 26, which holds the unopened can from any rearward movement as it is otherwise centered by the

stops

24 and 25 and bars 32 for the opening operation. The operator then presses a button 14 which activates the platform 20 to raise it and the centered can on it against the blade 50 until the edges 54 complete and join the cuts along the line CE, shown as a partially completed cut in FIG. 11. By the return stroke of the cylinder 12 the platform 20, with the opened can resting on it, is lowered to its initial position to complete the cycle and permit the cycle to be repeated with a succeeding unopened can.

Referring particularly to FIGS. 8-11, it is to be noted that the cutting edges 54 converging to the piercing point 53 on each segment 51 of the blade 50 are formed by bevels extending from the outside diameter down to the inside diameter of the blade and that the outside diameter of the blade is substantially equal to the inside diameter of the can C below the crimped sealing rim CR. This configuration and proportion of the blade 50 provides several advantages: As a consequence of the location of the actual cut edge CE in the can lid CL inside the rim CR (due to the necessary radial thickness of the blade 50), a substantial annular residual panel RP between the cut edge CE and the can rim CR is left. Heretofore, due to its sharp edge likely to cut the hands or fingers of anyone handling the opened cans, any such residual panel had to be avoided or minimized in commercial can-opening machines subject to safety regulations for health and/or labor. In machines made according to this invention, however, as the can rim CR and the residual panel RP are progressively engaged by the bevels of the edges 54, until the entire residual panel RP has been engaged by the outside diameter of the blade, the can rim CR is expanded and swaged outwardly to a new diameter equal to twice the gauge of the wall of the can and the gauge of the residual panel RP. Simultaneously the residual panel and, particularly, any sharp burrs on its edge, are forced downwardly and outwardly against the inside of the wall of the can C (also slightly expanded to the depth of travel of the blade 50 within it), thereby rendering the opened can entirely safe to handle at any point on its rim. A particular advantage of the swaging action effected by a blade 50 having the abovedescribed configuration is that it thereby also straightens any dents in the rim CR or an adjacent portion of the wall of the can, if such dents are not so major as to have disrupted the lid, wall, or the crimped seal in the rim CR and which would thus require discard of the can and its contentsin any event. Still another advantage of the action of the blade 50 on the can rim CR is that the rim is enlarged beyond the edge of the opening 34, thereby insuring that the stripper plate 30, attached to the platform 20, will strip the can C from the blade as the platform 20 is drawn down byreturn stroke of the cylinder 12. Automatic lid removal means and operation.

As best shown in'FlGS. 8, 12, and 13, each segment 51 of the blade 50 is secured to the ring 52 so as to provide a gap 55 at which the leading edge 54a of one segment 51 is overlapped by the trailing edge 54b of an adjacent segment. The upper portion of each segment is relieved to a depth below these overlaps to provide a horizontal shoulder 56 on the inside surface of the blade 50. As the upward movement of the can C against the edges 54 of the blade 50 completes the cutting of can lid CL, the drag of the segments against the lid CL tends to bend its out edge downwardly and dish the lid upwardly toward its center until the shoulder 56 passes below it, whereupon the slightly dished lid snaps outwardly and this drag is relieved. The final completion of the severing of the lid CL from the residual panel RP is achieved when the trailing edge 54b of one segment 51 passes below the lid CL and the last portion of the cut edge CE is made by the leading edge 54 of an adjacent segment 51. At thetime the severing is completed, the vertical gap between the cutting edges 54 of the segments 51 forms slight tips T in the severed can lid CL and the'final cuts by the trailing edges 54b also spin the jar and lid CL slightly so that as the can C is drawn downwardly by the stripper plate 30, the lid CL is certain to be retained on the shoulders 56.

As best shown in FIGS. 3 and 4, atone side of the base plate 10 and slanting upwardly and beyond the cutter head plate 40 is a chute 60. A pair of

brackets

60 and 62 support a forked striker plate 63 outboard of the chute 60, the tines of the striker plate 63 being bent outwardly above the upper bracket 62. Outboard of the striker plate 63, a shaft 64 is joumaled insuitable blocks 65 on the upper bracket 62. Intermediate the blocks 65 there is secured a bell-crank arm 66 carrying at its end one or more lid-lifting magnets 67, preferably permanent magnetsbut which may be electro-magnets. One end of the shaft 64 extends forwardly through a block 65 where, on its forward end, it is provided with a lifting cam arm 68 and a positioning cam arm 69.

The stripper plate post 31a, made heavier than the other posts 31 for this purpose, carries a horizontal actuating'arm 70 on the outboard end of which a pair of cam-

follower brackets

71 and 72 are provided for actuating the

cams

68 and 69, respectively.

When the platform 20 is raised (as shown in FIG. 2 and in phantom in FIG. 4) the engagement of the follower 72 with the positioning cam arm 69 will have pivoted the shaft 64 toward the opening 62 in the cutter head plate 40 until the over-balanced weight of the ball-crank 66 causes it to fall toward the opening 42; free-fall of the bell-crank 66 is restrained, however, by engagement of the can arm 68 with the follower 71 until the platform 20 approaches the end of its upward stroke, whereupon the clearance between the cam arm 68 and follower 71 allows the magnets 67 to fall on and hold a severed cam lid CL retained on the blade shoulders 56. As the platform 20 is lowered, the follower 71 again engages the arm 68, pivoting the shaft upwardly to lift a severed lid through the opening 42 until the bell-crank 66 is over-balanced outwardly and falls free to its position shown in FIGS. 3 and 4; in doing so, the upper side of the severed can lid carried by the magnets 67 is released from them by striking the tines of the striker plate 63. Thereupon the lid CL slides down the striker plate tines into the chute 60 and thence to a suitable disposal bin (not shown).

During use, the above-described embodiment is preferably provided with a hood 80, made entirely of rigid transparent plastic sheet in this instance. The hood 80 preferably covers the portion of the machine above the stripper plate 30 when the latter is in its lowered position. The hood 80 protects the opened cans from any foreign matter which might fall into them while centered on the platform as well as preventing the operator from accidentally touching the lid of the can and thus endangering his hand or fingers while the lid is being severed; it also protects the operator from any contents of the cans which may be splashed during the lid-severing operation. There is normally provided, however, an outboard opening 81 in the hood to allow the operator to reach in and dislodge any severed can lid which may have accidentally lodges at the entrance to the chute 60. The hood 80 is conveniently carried on the cutter head 40 by providing slots 82 which rest on the ends of the shaft 64 and allow the hood to be pivoted for access to the blade 50 or removed for cleaning the hood and the machine; suitable stops (not shown) on an inside vertical wall or walls of hood 80 engage the upper surface of the cutter head plate 40 and maintain the hood in the position shown in FIG. 1.

The relative movement between the platform 20 and the fixed elements of the machine permit the use of a counter which aids in the control of the operations of the kitchen, such as detecting pilferage of cans from stock before they are opened for use. In this instance a counter 90 is shown mounted on the chute 60; the counter level is actuated by a spring 91 connected to the arm 70 carried by the post 31a on the platform 20.

Construction and operation of machines without automatic lid removal.

In some smaller restaurant operations the labor savings of the automatic lid-removal in the abovedescribed machine does not warrant the cost which this feature adds to the price of the basic machine. Also, certain very viscous foods (such as pumpkin-pie fillings, for example) will have become adhered to the inside of the lid during normal shipping and handling of the unopened cans. For such viscous foods, the weight of the substantial amount which may cling to the underside of the severed lids may be overcome by increasing the strength of the lid-lifting magnets, but this expedient does not solve the problem caused by tendency of such foods on the lids to cause the lids CL to jam in disposal means, such as the chute 60, andthe consequent frequent shut-downs to dislodge such jammed lids and to clean the parts of the machine contacted by such foods on the lids. While it is simple enough to deactivate the lid-removal feature of the machine shown in FIGS. 1--14 by providing the cam follower 72 with a slot 73 allowing the follower to be moved to an inoperative position by pivoting the follower 72 on the lower of the two machine screws securing it to the arm 70, there is a demand for machines made according to this invention but not equipped with automatic lid-removal equipment, both in smaller restaurants and in larger restaurants where substantial number of cans of viscous foods may have to be opened. A machine meeting this demand is shown in'FlGS. 15-17.

Referring to FIGS. 15-17, the machine comprises a suitably supported base 110 carrying a cylinder mechanism 112 for reciprocating the shaft 113 supporting a platform 120 identical to the platform 20 and carrying identical elements. The cylinder mechanism 112 is actuated and cycled by control buttons 1 14 similar to the buttons 14. In this instance the legs 111 of the base 1 10 also support an unloading counter 115 located at the level of the platform when the latter is in its lowered position. A removable hood 180 is supported on and encloses a cutter head plate 140 supplied by posts 141 carried by the base 110. The hood 180 also encloses the stripper plate having a central opening 134; it is connected to the platform 120 by the stripper plate posts 131 and joumaled on the posts 141 for vertical reciprocation with the platform 120. The central opening 134 is concentric with the blade 150 carried by the head plate and its diameter is large enough to permit passage of the blade but smaller than the expanded rim of a can opened by the blade.

Referring to FIGS. 16 and 17 for details of the elements concealed within the hood 180 as shown in FIG. 15, the blade 150 in this instance differs from the above-described blade 50 in that it is not segmented, but formed from a cylindrical tubing of tool steel welded to a blade ring 152. In this instance the blade ring 152 is likewise bolted to the head plate 140 for removal for sharpening or repair of the beveled cutting edges of the blade 150 but the ring 152 is preferably spaced from the head plate by bosses 157 to facilitate cleaning of the machine (usually by steam or hot water jets); such spacing avoids a joint between the ring and plate from which food which might otherwise seep into such a joint would be difficult to remove. I

Because of the different manner of removing the severed can lids from the blade 150, no internal shoulder corresponding to the shoulder 56 in the blade 50 is provided and the internal diameter of the blade 150 is cylindrical throughout its vertical length. However, the outside diameter of the blade 150 is, as is the blade 50, proportioned to be slightly larger than the inside diameter of the can C so as to effect the same swaging of the residual panel left when the lid is severed, straightening dents, and enlargement of the rim of the can, as is effected by the above-described blade 50. As also in the case of the blade 50, the blade 150 is provided with four equally spaced piercing points 153 providing an included angle of 100l 10 between the cutting edges 154 converging to each point. Since no radial shifting of a severed lid is needed or required in this embodiment, neither cutting edge 154 adjacent a piercing point 153 need be a leadingor trailing edge and the angle of each to the plane of the can lid is substantially equal within the preferable range of 35-40.

Extending diametrically across the opening 142 in the head plate 140 is a lid knock-down bar drilled at the centerline of the opening to provide a bearing for a freely reciprocal vertical knock-down pin 161. The upper end of this pin carries an enlarged weight 162 and when this weight rests on the bar 160, the lower end of the pin ,161 extends downwardly at least nearly to the plane defined by the piercing points 153 (as shown in-FlG. l7) and may extend downwardly as far as the stripper plate 130 when the platform 120 is in its lowered position. The mass of the weight 162 is sufficient to exceed the drag of the cut edge of a severed I can lid on the internal cylindrical wall of the blade 150.

In the operation of the embodiment shown in FIGS. 15-17, the operator (or operators) load and unload cans onto and from the platform 120 in precisely the same manner as described for the platform 20, and by pressing one of the corresponding buttons 114 the platform 120 is similarly cycled through a vertical reciprocation to sever the lid from a can centered on the platform. Shortly before or soon after the piercing points 153 commence to cut a can lid on the line CE, the center of an incompletely severed lid engages the lower end of the knock-down pin 161, lifting it and the weight 162 as the can is lifted by the platform 120 until the blade 150 has completely severed the lid at the upper end of the stroke. As the platform 120 is lowered, the known-down pin 161 biased by the weight 162 causes the severed lid to rest on the contents and travel down with the can as it is lowered. After the opened can has been pushed off the platform 120 by an unopened can onto a suitable unloading counter or conveyor, one side of the severed lid is pushed down by hand on the contents until it can be grasped and manually removed. Such manual removal of a severed lid has been a conventional operation, but is much safer when the can has been opened by a machine illustrated in FIGS. 15-17, due to the swaging of the residual panel against the inside of the can wall, thereby eliminating the substantial danger that fingers might be scraped or cut on the sharp edge of the residual panel, as existed heretofore.

FIGS. 18 and 19 show another modification meeting the same demands satisfied by the embodiment shown in FIGS. 15-17. However, this further modification provides a more positive replacement of the lid on the contents of the can after the lid is severed, rather than automatically removing the severed lid, as in the embodiment shown in FIGS. 1-14.

Referring to the modified portions of the machine as shown in FIGS. 18 and 19, and which, as in the modifi cation shown in FIGS. 15-17, may be enclosed within a suitable hood as shown in FIG. 15, a fixed head plate 240 is supported by the posts 241 mounted on a base (not shown, but similar to the

bases

10 and 110 of the embodiments shown in FIGS. 1-17). The head plate 240 carries beneath it a non-segmented circular blade 250 formed from a tubing of tool steel similar to the blade 150; like that blade, the blade 250 is welded to a blade ring 252. The ring 252 is bolted to the head plate 240 to permit removal for sharpening of repair of the blade s beveled cutting edges 254; as in the case of the blade 150, piercing points 253 are formed by the convergence of cutting edges at an included angle of l-l Also, as in the case of the blade 150, bosses 257 space the blade ring 252 from the underside of the head plate 240 for ease of cleaning. A stripper plate 230 is journalled onvthe posts 241; it is supported by stripper plate posts 231 connected to a reciprocatable can-supporting platform (not shown, but similar to the

platforms

20 and 120 of the embodiments shown in FIGS. l-17). The central stripper plate opening 234 (as in the case of the

openings

34 and 134 in the embodiments shown in FIGS. 1-17) is concentric with the blade 250; it diameter is smaller than the expanded rim of a can C opened by the blade 250 but large enough to permit the blade 250 to pass through the stripper plate 230 as that plate is raised and lowered by reciprocation of the platform on which the plate 230 is mounted. As shown in FIG. 18, a stripper plate may have its forward edge bent upwardly to guide an unopened can being placed on the can-supporting platform.

Extending diametrically across the opening 242 in the head plate 240 is a knock-down bar260 carrying a downwardly depending knock-down pin 261 located concentrically in the opening 242. The lower end of the knock-down pin extends almost to the plane of the stripper plate 230 and thus below the plane of the piercing points 253 when the stripper plate is in its lowermost position, as shown by solid lines in' FIG. 19. The ends of the bar 260 are supported on posts 262; the posts 262 extend through holes 263 drilled through the head plate 240 to' the stripper plate 230, to which the posts 262 are connected. 7

The operation of the portion of the machine as shown in FIGS. 18 and 19 is as follows: With a can C centered on the can-supporting platform and a control button pressed to commence the cycle of vertical reciprocation of the platform, the stripper plate 230, the knockdown bar 260, and'its pin 261 move in unison with the platform to which they are connected by means of the

posts

231 and 262. As the can C is raised and its lid is first pierced by the points 253 and then completely severed by edges 254 as the can is raised to its uppermost position, the rim' and adjacent side wall portions of the can C are expanded and straightened (as shown in phantom in FIG. 19) and the residual panel of the severed lid is swaged down against the inside wall of the can, as in the embodiments shown in FIGS. l-17. If the cycle were stopped at this uppermost point (indicated by the phantom showing of the bar 260 in FIG. 19) both the can C and its severed lid may be hung'up on the blade 250; that is, the expanded rim and adjacent wallportion of the can C may grip the outside of the blade 250 and the severed lid, having been at least slightly flexed during the severing of it from the residual panel, may be held by its edge against the inside of the blade 250. As the can-supporting platform commences the return phase of the reciprocation cycle, however, first the inside edge of stripper plate opening 234 engages the expanded rim to strip the can from the blade and then the lower end of the knock-down pin, which had previously been held away from the can lid, strikes the severed lid held within the blade and positively and firmly pushes the severed lid downwardly below the piercing points 253 and, thus, where the severed lid is then free to fall onto the contents of the opened can. As in the case of lids severed by the modification shown in FIGS. l5l7, thereafter, when the opened can is pushed onto a suitable counter or conveyor by an unopened can centered on the lower platform, the can lid may be removed manually, as by pressing one side until the lid is tilted and may be grasped for removal.

This invention is not to be limited to the specific embodiments disclosed; in addition to the modifications disclosed still others may be made by those skilled in the art without departing from the spirit and scope of this invention as set forth in the appended claims.

What is claimed is:

1. In a can-opening machine of the class described, a base member, a platform for supporting an unopened vertical-walled can having a lid to be severed therefrom, said lid being substantially parallel to the plane of the platform when the unopened can is placed piercing points defined by downwardly converging cut ting edges located on the inside surface of the blade, the outside surface of the blade being beveled to said cutting edges and also being slightly larger than, but of a configuration otherwise congruent with, the inside of the can wall, means for centering said can on said platform so that its lid is substantially congruent with said blade and the locus of said piercing points will fall within the area of said lid, means for causing said platform with said centered can thereon and said blade, with its piercing points extending toward said lid, to move relatively toward each other until said cutting edges completely sever a center portion of said lid along a cut edge spaced inwardly from the rim joining said can wall and said lid, said spacing defining a residual panel left attached to said can wall, whereby the passage of said blade into said can to a depth where said bevels are below said rim, swages said rim and adjacent portions of the can wall outwardly and also swages said residual panel against the inside wall of said can, means to move saidplatform and said blade relatively away from each other, and means to maintain said can on said platform and strip its expanded rim from said blade as said platform is moved away from said blade in the cycle of reciprocal movement of the same with respect to each other.

2. A can-opening machine as defined in claim 1,- in which the number of piercing points on said 'blade ranges between and includes three and five, the included angle between said cutting edges converging at said piercing joints ranges between 100l the angle of any one cutting edge to the plane of said lid ranges between 3045, and the means for stripping said expanded cam rim from said blade comprises a stripper plate connected to said platform at a distance permitting said can to be slid therebetween, said plate having an opening therein through which said blade passes in severing said lid, the edge of said stripper plate engaging the expanded rim of said can as said platform is reciprocated away from said blade.

3. A can-opening machine as defined in claim 2 in which said means for centering said can on said platform includes a cam plate means, stops on said plate means engaging the sidesof a lowerrim of said can to center it beneath said blade, a lateral cam carried by said plate and positioned to be engaged by a side of a can pushed toward the area on said platform where said can will be centered but which lateral cam is engaged and moved by said can before the can enters said area so as to deactivate and remove said stops from engagement with a can within said area, and a center cam on said plate configured and positioned to allow a can to be moved forward toward its centered position until the can engages said stops and thereafter restraining said can from rearward movement, said lateral cam deactivating said stops being cleared by the side of a can as it enters said centering area to re-activate said stops before the can entering said area is restrained from rearward movement by said centered can 4. A can-opening machine as defined in claim 3 in which said means for causing said platform to reciprocate toward and away from each other comprises a vertical shaft connected to said platform, drive means carried by said base member and operative to reciprocate said shaft through a single cycle moving said platform vertically above said base member and returning it to its lowered position at the beginning of the cycle,

means supporting said blade in a fixed position which is above said stripper plate when said platform is in its lowered position, and means to actuate said drive means through said cycle.

5. A can-opening measn as defined in claim 4 in which the piercing points on said blade are four, equally spaced from each other and positioned to engage the lid of a can substantially simultaneously when said platform and a centered can thereon are raised toward said blade.

6. A can-opening machine as defined in claim 4 comprising a knock-down pin supported for reciprocal movement at the substantial centerline of said tubular blade, the lower end of said pin, when said platform is in its lowered position, being located at or adjacent the plane defined by the piercing points of said blade, and biasing means resisting upward movement of said pin when it is engaged by the lid of a can raised toward said blade by said platform, the force of said biasing means on said pin being greater than the drag of a completely severed lid on the inside wall of said tubular cutting blade, whereby when said platform is lowered, said pin forces said severed lid out of said blade and onto the contents of the can opened by said blade.

7. A can-opening machine as defined in claim 4 in which said blade is supported by a plate having an opening therein centered above said tubular blade, the area of said opening being larger than but otherwise congruent with the minimum inside area of said blade, an inner shoulder on said blade above its piercing points, but below the depth of said blade where said converging cutting edges completely sever said lid, whereby, when said lid is severed, said lid will be free to fall onto said shoulder, and means to lift said lid from said shoulder through said opening.

8. A can-opening machine for cans of magnetic metal as defined in claim 7 in-which said means to remove said lid through said opening comprises magnet means, means to lower said magnet means into said-opening to contact and attract said lid-thereto and thereafter lift said magnet means and attached lid through said opening to an outboard position, means to removesaid lid from said magnet means at said outboard position and means connecting said platform and said means for lowering and lifting said magnet means so as to lower said magnet means onto said lid when the platform is at or approaching its maximum raised position and to lift and to move said magnet to an outboard position and there remove said lid therefrom as said platform returns to its lowered position.

9. A can-opening machine as defined in claim 8 in which said means for lowering and lifting said magnet means comprises a crank means carrying said magnet means, a shaft on which said crank means is pivoted, cam means on said shaft, and cam follower means supported on said platform to activate said cam means on said shaft to pivot said crank means between said lowered position and the maximum lifted position for said magnet means.

10. A can-opening machine as defined in claim 9 in which said means for removing said lid from said magnet means comprises a fixed member for striking said lid from said magnet means as said magnet means is pivoted toward its maximum lifted position and including a chute to receive a lid removed from said magnet means and direct the removed lid to a receptacle for disposal thereof.

11. A can-opening machine as defined in claim 4 comprising a knock-down pin, means supporting said pin at the substantial center-line of said tubular blade, the lower end of said pin being located adjacent or below the plane defined by piercing points of said blade and above the plane defined by the rim of the can centered on said platform when said platform is in its lower position, said pin-supporting means causing said pin to reciprocate simultaneously with the reciprocal movement of said platform, whereby said knock-down pin will engage and knock down a severed can lid which may otherwise be held within said tubular blade as said platform, carrying an opened can, is returned to its lowered position but said pin will be held away from said lid until said platform commences its return movement.

12. A can-opening machine as defined in claim 11 in which knock-down pin supporting means comprise members connected to said stripper plate and extending above means supporting said tubular blade, said means supporting said pin in a depending position at the substantial center-line of said blade and, when said platform is in its lowered position, maintaining the lower end of said pin at a level below the plane defined by said piercing points, whereby return of said platform and said stripper plate to their lowered positions will cause positive movement of said pin to knock down a severed can lid held frictionally within said blade to a position where said lid is free of said blade.

Claims

1. In a can-opening machine of the class described, a base member, a platform for supporting an unopened vertical-walled can having a lid to be severed therefrom, said lid being substantially parallel to the plane of the platform when the unopened can is placed thereon, a tubular cutting blade having a plurality of piercing points defined by downwardly converging cutting edges located on the inside surface of the blade, the outside surface of the blade being beveled to said cutting edges and also being slightly larger than, but of a configuration otherwise congruent with, the inside of the can wall, means for centering said can on said platform so that its lid is substantially congruent with said blade and the locus of said piercing points will fall within the area of said lid, means for causing said platform with said centered can thereon and said blade, with its piercing points extending toward said lid, to move relatively toward each other until said cutting edges completely sever a center portion of said lid along a cut edge spaced inwardly from the rim joining said can wall and said lid, said spacing defining a residual panel left attached to said can wall, whereby the passage of said blade into said can to a depth where said bevels are below said rim, swages said rim and adjacent portions of the can wall outwardly and also swages said residual panel against the inside wall of said can, means to move said platform and said blade relatively away from each other, and means to maintain said can on said platform and strip its expanded rim from said blade as said platform is moved away from said blade in the cycle of reciprocal movement of the same with respect to each other.

2. A can-opening machine as defined in claim 1, in which the number of piercing points on said blade ranges between and includes three and five, the included angle between said cutting edges converging at said piercing joints ranges between 100*-110*, the angle of any one cutting edge to the plane of said lid ranges between 30*-45*, and the means for stripping said expanded cam rim from said blade comprises a stripper plate connected to said platform at a distance permitting said can to be slid therebetween, said plate having an opening therein through which said blade passes in severing said lid, the edge of said stripper plate engaging the expanded rim of said can as said platform is reciprocated away from said blade.

3. A can-opening machine as defined in claim 2 in which said means for centering said can on said platform includes a cam plate means, stops on said plate means engaging the sides of a lower rim of said can to center it beneath said blade, a lateral cam carried by said plate and positioned to be engaged by a side of a can pushed toward the area on said platform where said can will be centered but which lateral cam is engaged and moved by said can before the can enters said area so as to deactivate and remove said stops from engagement with a can within said area, and a center cam on said plate configured and positioned to allow a can to be moved forward toward its centered position until the can engages said stops and thereafter restraining said can from rearward movement, said lateral cam de-activating said stops being cleared by the side of a can as it enters said centering area to re-activate said stops before the can entering said area is restrained from rearward movement by said centered can

4. A can-opening machine as defined in claim 3 in which said means for causing said platform to reciprocate toward and away from each other comprises a vertical shaft connected to said platform, drive means carried by said base member and operative to reciprocate said shaft through a single cycle moving said platform vertically above said base member and returning it to its lowered position at the beginning of the cycle, means supporting said blade in a fixed position which is above said stripper plate when said platform is in its lowered position, and means to actuate said drive means through said cycle.

8. A can-opening machine for cans of magnetic metal as defined in claim 7 in which said means to remove said lid through said opening comprises magnet means, means to lower said magnet means into said opening to contact and attract said lid thereto and thereafter lift said magnet means and attached lid through said opening to an outboard position, means to remove said lid from said magnet means at said outboard position and means connecting said platform and said means for lowering and lifting said magnet means so as to lower said magnet means onto said lid when the platform is at or approaching its maximum raised position and to lift and to move said magnet to an outboard position and there remove said lid therefrom as said platform returns to its lowered position.