US2924093A - Testing and rejecting apparatus for vacuum packed cans - Google Patents

Description

G. L. HURST Feb. 9, 1960 TESTING AND REJECTING APPARATUS FOR VACUUM PACKED CANS Filed Oct. 12 1953 2' Sheets-Sheet 1 INVENTOR.

Feb. 9, 1960 v G. L. HURST 2,924,093

TESTING AND REJECTING APPARATUS FOR VACUUM PACKED CANS v f-| -a I 4 /7 /2 F/7 i i E i i INVENTOR. r 650/965 1. H0957 M, 77 fit 1&7

@ l 147 TOR/V15 f5 United States Patent TESTING AND REJECTING APPARATUS FOR VACUUM PACKED CANS George L. Hurst, Redwood City, Calif.

Application October 12, 1953, Serial No. 385,356

7 Claims. (Cl. 7345.4)

This invention relates to apparatus for testing the degree of vacuum in vacuum packed cans, such as coffee cans, and rejecting cans in which the degree of vacuum as to cause such tops to deflect outwardly. The amount of such deflection is, of course, inversely proportional to the degree of vacuum in the can. Means responsive to the amount of such deflection, is generally provided for operating a rejecting arm or plunger so as to positively push a rejected can off the normal path of travel and into a chute or some other conveyor means which conveys the rejected cans to another station.

To produce a suction externally on the cans, it is necessary to provide a suction head movable with the can conveyor and adapted to make an air tight seal with the top peripheral rim of the can. Obviously, the measurement of the deflection of the can top must be made while the suction head is in air tight engagement with the can, therefore the rejecting operation by which the can is removed from the can conveyor cannot be performed until the can is released from the suction head.

The generally adopted method is to save the deflection reading by providing a deflection responsive means for each can and a separate electrical circuit for each deflection responsive means and which circuits are adapted to close when a dcfectively packed can is engaged. However, inasmuch as closing of the circuits energizes a solenoid to impart the necessary motion to the ejecting plunger or arm, it is necessary to save the deflection reading by a time delay device of some sort so that ejection always takes place at the same point in the path of travel of the cans. At such point the can has already been released from the vacuum head.

Such a system leads to complications and the chances of an inaccurate test are increased. Furthermore there are many electrical switches to get out of adjustment and the provision of the time delay obviously increases the total cost of the installation.

In addition, to the above mentioned disadvantages, the use of a positively acting can ejecting arm or plunger slows down the testing and rejecting operation inasmuch as such arm or plunger must be withdrawn across the path of travel of the cans before the next can arrives at the ejection point.

The main object of the present invention is, therefore, the provision of a vacuum packed can testing and rejecting apparatus which is considerably simpler in operation than those heretofore employed and which apparatus is cheaper to construct and more eificient in operation than prior art apparatus of like nature.

Another object of the invention is the provision of an improved vacuum packed can tester which requires only one simple electrical circuit and one switch.

Still another object of the invention is the provision of an improved mechanism for ejecting defectively packed cans.

Other objects and advantages will be apparent from the following specification and drawings.

Fig. 1 is a top plan view of a can conveyor system showing the testing and rejecting means.

Fig. 2 is a side elevational view of the apparatus of Fig. 1 with a portion of the same broken away to show internal structure.

Fig. 3 is a greatly enlarged fragmentary vertical crosssectional view through the apparatus of Fig. 1 as taken along lines 33 of that figure and showing the essential elements of the testing and rejecting means.

Fig. 4 is an enlarged side elevational view of the invention showing the means for resetting the deflection gage elements, as seen along line 4-4 of Fig. 1.

Fig. 5 is an enlarged semi-schematic plan view of the electromagnet and adjacent structure as taken along lines 55 of Fig. 3 and showing the operation of the invention during ejection of a defectively packed can.

In the following description, the conventional apparatus will be described briefly and only the invention claimed herein will be considered in detail.

The cans are fed to the testing conveyor by a rotary support 1 (Fig. .1) which, in combination with known devices, spaces the cans apart a predetermined distance so that one can is received by a revolving can support 2 of which twelve are shown in the drawings (Fig. 1). These can supports 2 are respectively supported on vertically disposed elongated members 3 (Fig. 2) which, in turn, are slidably received in bearings 4 formed at spaced points around the periphery of a relatively large dished carrier 5. This carrier 5 is rotatably supported on a central vertically extending stationary shaft 6 and is provided with an'internal gear 7 with which a pinion 8 meshes. Pinion 8 is fixed to the upper end of a vertical shaft 9 which in turn is rotatably supported in a hearing it The lower end of shaft 9 is provided with a bevel gear 11 which is driven by another bevel gear 12 on shaft 13. Rotation of the dished member 5 is effected through a chain drive 14 between motor 15 and shaft 13 (Figs. 1, 2).

The lower ends of the vertically disposed members 3 are provided with rollers 17 which engage a stationary circular cam track 18 designed to move the cam supports 2 to any predetermined elevation during rotation of the carrier 5.

Rotation of the can supports 2 relative to carrier 5 is prevented by radially inwardly extending arms 19 rigidly secured to supports 2 and apertured at their inner ends to receive upwardly extending rods 20 which in turn are rigidly secured at their lower ends to the upper surface of the carrier 5.

Above the carrier 5 and supported for rotation about shaft 6 with said carrier is a horizontally extending top 22 which is provided on its under side with a plurality of suction heads generally designated 23 (Fig. 3) and respectively adapted to be engaged by the cans 24 on supports 2. The heads 23 are each provided with a downwardly opening annular groove 25 which receives an annular gasket 26 of resilient material such as rubber (Fig. 3). Thus, as best seen in Fig. 3, upon upward movement of a can support 2 by the action of cam track 18 the upwardly directed peripheral rim 27 of can 24 is moved into air tight engagement with the gasket 26 to form a chamber 28 between the top 21 of the can 24 and the head 23 (Fig. 3).

Communicating with such chamber 28 through each head 23 is one end of a conduit 29. The conduits 29 for all of the heads 23 are connected at their corresponding opposite ends to a conventional rotary valve mechanism positioned centrally of top 22 and including a stationary vacuum chamber 30' secured at the inner end of a radially extending arm 31. This arm 31 extends horizontally over the top 22 and is bent downwardly at its outer end (Fig. 3) to provide a vertically extending portion 32 which is stationarily secured to any suitable structure.

The vacuum chamber 30 is exhausted through a suction line 33 (Fig. 2) which is connected to any suitable source of vacuum (not shown) for applying a predetermined suction.

Secured to top 22 is a valve head 34 (Fig. 2) which is provided with a suction port 35 and an exhaust port 3'6 (Fig. 1).

In operation, when the cans 24 are received on supports 2 (Fig. 1), the latter are spaced downwardly from their corresponding suction heads 23. Upon rotation of the carrier 5 in a clockwise direction as indicated in Fig. 1, the action of cam track 18 is such that the cans 24- are moved upwardly into air-tight engagement with the gasket 26 of head 23 as shown in dotted lines in Fig. 3.

At this point the conduits 29 connect with the suction port 35 and a suction is applied to the space 28 between the tops of the cans and the heads 23. After the upward deflection of the tops of the cans is measured (in a manner to be described) further rotation of the carrier 5 connects the conduits 29 with the exhaust port 36 and the cans are thereby freed from their corresponding heads and are ready for further processing.

The structure above described is conventional and no claim is made thereto except in combination with the novel feature constituting the present invention and which features will now be described.

For the purpose of gaging the upward deflection of the tops 21 of cans 24 when an external suction is applied thereto, I provide a vertically extending central bore 40 through each suction head 23, the latter being provided with an upwardly extending boss 41 so that the upper end of said boss is above and clear of the conduits 29 (Fig. 3).

Slidably received in bore 40 is an elongated pin 42 which is formed at its lower end with an enlarged head 43 having a downwardly directed convex portion adapted to engage the tops 21 of cans 24 at a point centrally of the latter.

The upper end of pin 42 extends through the top of boss 41 and is threaded to receive a bushing 44 which is flanged at one end to support a disk-like element 45. A nut 46 screw-threadedly engages bushing 44 and disk 45 for releasably locking the latter at various points along the length of rod 42 as desired. An upwardly opening recess 47 is formed in boss 41 to permit downward movement of the bushing 44 with pin 42 from the position shown in Fig. 3 if required.

The pin 42 is preferably freely slidable in bore 40, but I provide means for adjustably varying the resistance to movement of pin 42 in bore 40. This comprises a ball 49 positioned in a radially outwardly opening hole in boss 41 and a short compression spring 50 for urging the ball 49 against pin 42. A screw 51 is received in the boss 41 so that rotation of the same permits varying the compression in spring 50 and therefore the friction between ball 49 and the periphery of pin 42.

By the above described structure it will be apparent that the friction on pin 42 may be adjusted so as to overcome the weight of pin 42 and also cause said pin 42 to stay in any position to which it is moved.

Supported on the underside of arm 31 is a switch 52 which includes a reciprocally mounted actuating pin 53 extending horizontally outwardly of switch 52 and into the path of travel of the disks 45 carried by such pins 42" that are man up position. With reference particu-- larly to Fig. 3, it is seen that the normal outer position of actuating pin 53 of switch 52 is such that disk 45, when in the dotted line position, interferes with the outer end of pin 53 just enough to cause the pin 53 to be urged inwardly of the switch to actuate the latter. The usual spring means (not shown) within the switch body urges the pin to its outer position again after the disk passes.

The switch 52 controls a circuit, generally designated 54 (Fig. 1) which includes a source of electrical energy 55 and an electromagnet 56.

This electromagnet 56 comprises a pair of upper and lower parallel pole pieces 57, 58 respectively (Fig. 3), core 5) and winding 60, the latter being in circuit 54 (Figs. 1, 3

Referring again to head 23 (Fig. 3), it is seen that when the conduit 29 corresponding to the suction head 23 is connected through suction port 35 to the source' of vacuum and the associated can 24 is in its up position as shown in dotted lines in Fig. 3, the partial vacuum created above can 24 tends to cause the top 21 to deflect upwardly. If the vacuum in can 24 is below a predetermined minimum, the amount of such deflection will cause pin 42 to be moved upwardly so as to shift disk 45 into the path of travel of actuating pin 53 on switch 52'. In this connection it will be understood that the thickness of disk 45 must be such that the disk will engage pin 53 for any possible range of deflections indicating a defective vacuum. Obviously, the disk 45 must be adjustably positioned so that when the vacuum in the can is just less than the permissible amount, the disk 45 will actuate switch actuating pin 53. In such a case the pin 53 will be engaged by disk 45 along the upper edge of the latter.

When the vacuum in can 24 is extremely poor the bottom of head 23 may act as a stop for the can top 21 as shown in dot-dash lines in Fig. 3. In such an event the disk 45 will move to the position shown in dot-dash lines in Fig. 3.

By making the bore 40 in head 23 relatively long, the leakage of air between pin 42 and bore 40 may be minimized. However to prevent any such leakage a conventional O-ring seal 62 may be provided on the bottom of recess 47 around pin 42 and such seal may be held against such bottom by spring clip 63. Such a seal will, of course, contribute at all times to the friction opposing movement of pin 42.

The electromagnet 56 is stationarily positioned alongside the path of travel of cans 24 and is mounted on a yoke 64 which, in turn, may be fastened to the vertically extending portion 32 of arm 31 (Fig. 3).

The upper and lower pole pieces 57, 53 are identical and each comprises substantially a sector of a circular plate. As best seen in Fig. 5 the electromagnet 56 is positioned with the pole pieces substantially tangent to but slightly'spaced radially outwardly from the circular locus of the outermost sides of cans 24 as the latter are moved in their circular path of travel as above described.

In Fig. 5 a can 24 is shown by dot-dash lines in its normal position A on can support 2 in which position it is seen that the can just clears the pole pieces of the magnet. The same can is shown in full line in position B to which it is attracted when the'electromagnet 56 is energized. Thus it will be seen that as said can comes to a position A alongside electromagnet 56, and if the latter is deenergized, such can will proceed along its normal circular path of travel and will finally be removed by a conventional rotary device generally designated 65 (Fig. 1).

However, if electromagnet 56 is deenergized when the can is in position A, such can will be attracted to position B and will remain in engagement with the pole pieces, until the electromagne't is deenergized.

Referring specifically to Fig. 5, it is seen that the continuous movementof can supports-- 2 will cause the can to be urged along the circular path of travel C of said supports but at the same time the magnetic attraction of the electromagnet 56 will hold the can to an arcuate path of travel D parallel to the peripheries of pole pieces 57, 58.

Extending slantingly downwardly from the path of travel of can supports 2 is a stationary reject chute 67 which is formed with an upper edge 68 concentric with said path of travel. Chute 67 is positioned so that a can, shifted from its can support 2 will, when moving along the reject path of travel D, come to a position E at which it is partially supported on edge 68 of chute 67 and also on its support 2.

Upon further movement of the can support 2, it will be clear that the can will move to a position E at which its center of gravity is past the upper edge 68 of a chute 67. If the electromagnet 56 is deenergized when the can is at position B it is obvious that such can will drop freely by gravity down chute 67. The apparatus by which the electromagnet 56 is energized and deenergized will now be described in greater detail.

As best seen in Fig. l, the switch 52 is positioned so that the same is actuated, in the case of a defectively packed can, when such can is alongside electromagnet 56 or, more accurately, when such can is in position A in Fig. 5.

I provide means for deenergizing the electromagnet 56 when the position of the can support 2 is such that its corresponding can is at the position of unbalance as indicated at E in Fig. 1. This means comprises a conventional resetting pin 70 on switch 52 (Fig. 3) and an elongated arm 71 which is swingably supported intermediate its ends on a pivot 72. One end of arm 71 is adapted to be engaged by disks 45 of suction heads 23 when a rejected can is in position B.

As best seen in Fig. l the disks 45 swing the arm 71 about pivot 72 causing the other end to depress resetting pin 70 thus breaking circuit 54 and deenergizing electromagnet 56 thus preparing the same for action on the next succeeding can if required.

It is important to note that the distance moved by the can supports 2 between the time electromagnet 56 is energized is less than the spacing between adjacent supports. By the arrangement shown in Fig. 5, it is apparent that ample time remains between the release from electromagnet 56 of a rejected can and the positioning of the next succeeding can alongside said electromagnet (position A).

It is emphasized at this point that no loss of time occurs which might otherwise result if a plunger arm, or other positive rejection member were required to eject a can into chute 67. In such a case, it would be necessary to retract the ejecting means before the next succeeding can reaches the reject point. By the present invention, no such loss of time is suffered.

The last step in the operation is to depress the pins 42 in heads 23 so that the same are all in the full line position of Fig. 3 and ready to be acted upon during the next revolution of carrier 5. This-is accomplished by a stationary arm generally designated 73 which is fastened at one end to the large valve support arm 31 and is formed along its length with a gradually downwardly extending lower surface 74 which is adapted to engage the upper ends of pins 42 and urge said pins downwardly against the resistance of spring urged ball 49 and seal 62.

It will be understood that the position of disks 45 relative to pins 42 may be adjusted so that all heads 23 function-in identically the same manner to subject all cans to the same test. However, it is well known in the industry that variations in atmospheric conditions will change the operation of pins 42 so that a further adjustment to suit different atmospheric conditions is desirable. However, inasmuch as a change in atmospheric conditions will affect all heads 23 equally I provide means for shifting the position of switch 52 and its actuating pin.

Switch 52 is preferably secured to the underside of a generally horizontally disposed radially extending plate 75 which is fastened at its inner end to the underside of arm 31 by means of bolt 76 and nut 77; both arm 31 and plate 75 being apertured to receive bolt 76 therethrough. A yieldable washer 78 of fiber or the like is interposed betweenplate 75 and arm 31 adjacent bolt 76 so as to permit limited movement of the opposite outer end of plate 75 and still hold switch support plate 75 against shifting under vibration.

The outer end of plate 75 is urged downwardly at all times by a leaf spring 79 and said plate and arm 31 are spaced apart by the shank of a bolt 80 which ispassed through a hole in arm 31 and threadedly engages a tapped hole in plate 75. A downwardly projecting boss 81 may be formed rigid with the underside of plate 75 so as to permit the tapped hole in plate 75 to be extended to a sufficient length.

By rotating bolt 80 it will be obvious that plate 75 may be swung slightly upwardly or downwardly to shift the position of switch actuating pin 53 as desired.

Bolt 80 may therefore be employed to alter the efiective action of pin 42 when changes in atmospheric conditions make such an alteration desirable.

By the invention herein described the testing and rejecting operations need not slow down the movement of the cans and said operations may be carried out at any desired speed.

It should be noted that the pole pieces 57, 58 of the electromagnet 56 offer no resistance to rotation of the rejected cans with the result that very little friction between the supports 2 and cans 24 is required to cause the cans to roll on the pole pieces 57, 58.

Although the device would operate satisfactorily if the can engaging surfaces of the pole pieces 57, 58 were of a different shape than that shown, it is preferable that the can engaging surfaces be circular. In this manner, the cans roll on the pole pieces and little or no resistance to such rolling is olfered.

I claim:

1. In a can handling system: a conveyor having supporting means for moving vacuum packed cans along a horizontal path of travel in one direction with the tops of said cans horizontal, means for moving said cans vertically toward and away from a testing position during said movement, an electromagnet positioned alongside the cans in said path, an electrical circuit including a stationary switch and the winding of said electromagnet for energizing the same, means cooperating with said cans at said testing position for successively applying suction externally to the tops of said cans for urging said tops upwardly, and means responsive to the upward movement of said tops for actuating said switch to close said circuit when the vacuum in any one can is less than a predetermined amount and said one can is at a point in said path alongside said magnet whereby a defectively packed can is attracted to said magnet, said magnet being formed with a can engaging surface inclined to said path so that urging of said one can in said direction by said supporting means will move said one can laterally 01f said path of travel, means for conveying such a rejected can away from said path, and means for opening said circuit before the next succeeding can is alongside said switch.

2. In a can handling system: a conveyor having supporting means for moving vacuum packed cans along a horizontal path of travel in one direction with the tops of said cans horizontal, means for moving said cans vertically toward and away from a testing position during said movement, an electromagnet positioned alongside the cans in said path, an electrical circuit including the winding of said electromagnet for energizing the same, means cooperating with said cans at said testing position for successively applying suction externally to the tops of said cans for urging said tops upwardly, vertically disposed gage elements carried by said conveyor and respectively positioned above the cans in said path, said elements being supported for movement from a normal lower position to an upper position under the urging of said tops when said suction is applied thereto, whereby a gage element is moved to said upper position when engaged by the top of a defectively packed can, stationary switch means adjacent said path and actuatable by said elements when the latter are in said upper position for closing said circuit and energizing said magnet whereby a defectively packed can is attracted to said magnet, said rejecting cans having less than a predetermined vacuum therein, means for supporting cans for movement along a predetermined horizontal path of travel with the axes of said can vertical, means for moving said cans vertically toward and away from a testing position during said movement, a stationary electromagnet positioned alongside but spaced laterally from the cans in said .path, a unitary electrical circuit including a coil in said magnet for energizing the latter, means cooperating with said cans at said testing position and actuatable by a defective can for closing said circuit when such defective can is alongside said magnet whereby a defective can is attracted to said magnet and held thereto, said magnet being provided with a can engaging surface angularly disposed relative to said path whereby movement of a defective can by said supporting means will cause such can to be rolled along said can engaging surface to a position with its axis offset from said path and means for opening said circuit when said can is in said last mentioned position before the next succeeding can cooperates with said circuit closing means.

4. In a rejection system for vacuum packed cans for rejecting cans having less than a predetermined vacuum therein, means for supporting cans for movement along a predetermined horizontal path of travel with the axes of said cans vertical, means for moving said cans vertically toward and away from a testing position during said movement, a stationary electromagnet positioned alongside but spaced laterally from the cans in said path, a unitary electrical circuit including a coil in said magnet for energizing the latter, means cooperating with said cans at said testing position and actuatable by a defective can for closing said circuit when such defective can is alongside said magnet whereby a defective can is attracted to said magnet and held thereto, said magnet being provided with a can engaging surface angularly disposed relative to said path whereby movement of a defective can by said supporting means will cause such can to be rolled along said can engaging surface to a position with its axis offset from said path, a stationary member alongside said can supporting means and including an upper edge adapted to partially support said can when the latter is moved to saidlast mentioned position with said can partially supported on said supporting means, and means for opening said circuit before the next succeeding can cooperates with said circuit closing means when the center of gravity of said can passes said edge whereby said can is overbalanced when the attraction of said electromagnet is arrested.

5. In a rejection system for vacuum packed cans for rejecting cans having less than a predetermined vacuum therein, means for supporting cans for movement along a predetermined horizontal path of travel with the axes of said cans vertical, a stationary electromagnet posif tioned alongside but space laterally from the cans said path, a unitary electrical circuit including a co'il i'n said magnet for energizing the latter, means actuatable by a defective can for closing said circuit when such defective can is alongside said magnetwhereby a defective can is attracted to said magnet and held thereto, said magnet being provided with an arcuate can engaging surface substantially tangent to said path at one point thereof and progressively more inclined to said path in a direction away from said point whereby movement of a defective can by said supporting means will causevsuch can to be rolled along said arcuate surface from said one point to a position with its axisspaced radially outwardly of said path, and means for opening said circuit when said can is in said last mentioned position. I

6. In a can handling system including a conveyor having supporting means for moving vacuum packed cans in single file along a horizontal path of travel with their axes vertical, a plurality of suction heads carried by said conveyor and respectively adapted to apply suction externally of the tops of said cans means 'for successively moving said cans into and out of engagement with said heads, vertically movable elements respectively carried by said heads and movable by the tops of defectively packed cans from a normal lower position to an upper position When said suction is applied, a stationary switch supported alongside a point on said path and switch actuating members carried by the upper ends of said elements respectively for actuating said switch when said elements are in said upper position, electrically actu ated ejecting means alongside said path for ejecting a defectively packed can from said path, an electrical circuit including said switch and ejecting means for actuating the latter when said switch is closed by one of said members. V

7. In acan handling system including a conveyor having supporting means for moving vacuum packed cans in single file along a horizontal path of travel with their axes vertical, a plurality of suction heads carried by said conveyor and respectively adapted to apply suction externally of the tops of said cans means for successively moving said cans into and out of engagement with said heads, vertically movable elements respectively carried by said heads and movable by the tops of defectively packed cans from a normal lower positionfto an upper posltion when said suction is applied, a stationary switch supported alongside a point on said path and switch actu ating members carried by the upp'erends of said elements respectively for actuating said switch when said elements are in said upper position, a stationary electromagnet positioned alongside said point of said path, an electrical circuit including said switch and the winding of said electromagnet for energizing said electromagnet when said switch is engaged by one of said rnembe'rswhereby a defective can at said point is attracted to said electro magnet, said electromagnet being provided with a can engaging surface inclinded to said path of travel and along which a defective can'may roll during movement of such can on said supporting means foiurging such can to a position with its axis offset from said path.

References Cited in the file of this patent UNITED STATES PATENTS 2,093,429 Foss Sept. 21, 1937 ,526 Cummings Dec. 1, 1942 2, 70,485 Rieber Oct. 9 1951 8 Watson Nov. 24, 1953 2,8 1,300 Rofinger et al. Jan. 28, 1958 MA -m

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