US2985008A

US2985008A - Transfer mechanism

Info

Publication number: US2985008A
Application number: US662856A
Authority: US
Inventors: Roland E Renard
Original assignee: National Can Corp
Current assignee: National Can Corp
Priority date: 1957-05-31
Filing date: 1957-05-31
Publication date: 1961-05-23
Anticipated expiration: 1978-05-23

Description

May 23, 1961 R. E. RENARD 2,985,008

TRANSFER MECHANISM 4 Sheets-Sheet 1 Filed May 51, 1957 INVENTOR. Ram/v0 f. Ram/e0 BY (7 L May 23, 1961 R. E. RENARD 2,985,008

TRANSFER MECHANISM Filed May 31, 1957 4 Sheets-Sheet 2 INVENTOR. P m/v0 PMAKD May 23, 1961 R. E. RENARD 2,985,008

TRANSFER MECHANISM Filed May 31, 1957 4 Sheets-$heet 3 l 1 mu /me Roland E.Renard J95 ATTORNEY May 23, 1961 R. E. RENARD 2,

TRANSFER MECHANISM Filed May 31, 1957 4 Sheets-Sheet 4 Roland E. Renard ATTORNEY United States Patent 2,985,008 TRANSFER MECHANISM Roland E. Renard, Los Gatos, Calif., assignor to National Can Corporation, Chicago, 11]., a corporation of Delaware Filed May 31, 1957, Ser. N0. 662,856

8 Claims. (Cl. 73-452) This invention relates to a new and improved discharge mechanism for can tester machines and relates further to a mechanism wherein objects such as cans are selectively transferred from one turret to another or retained in the first turret. customarily, after they have been manufactured and before they are shipped to customers, cans are tested for leaks. At this stage of their manufacture, the cylindrical can bodies have been formed and a can end has been seamed to one end, the opposite end being open. The present mechanism has particular utility in segregating the leaky cans detected by the tester machine as they are released from the tester. This application is a continuation in part of prior application Serial No. 564,900, now Patent No. 2,868,373, filed February 13, 1956, for Discharge Mechanism for Can-Testing Machine.

There are several difierent types of can-testing machines currently used. The details of construction of such machines and the manner of their functioning forms no part of the present invention except as hereinafter appears. Essentially a can-tester machine comprises a very large diameter wheel revolving about a horizontal axis and carrying on its periphery a plurality of can-receiving pockets. The cans to be tested are inserted one at a time in the pockets and sealed therein by closures for the pockets which engage and seal against both the lip of the pocket and the open end of the can deposited therein. As each can is carried around the machine in its pocket, compressed air is applied to the interior of the can exclusive of the pocket. If there is no leak in the can, the volume of air within the chamber surrounding the can remains at atmospheric pressure. However, if there is a leak in the can, the pressure in this chamber rises to approximately the pressure of the air in the can. Pressure-responsive means is provided to detect the rise in pressure in the defective can pocket and this detection is recorded in a memorizer which functions to store information and subsequently actuate a means to discard the leaky can after the can has been discharged from its pocket.

The present invention relates to an improved discharge mechanism which receives the cans as they are released from their pockets and segregates the defective cans.

The present invention difiers from prior constructions in that it employs two adjacent rotating turrets, each of which is formed with a plurality of can-receiving pockets with a permanent magnet disposed in each pocket. As the cans are discharged from the tester wheel, they are deposited in the pockets of the first discharge turret and carried around by the first turret. The second turret intersects the path of the first turret, but is displaced therefrom a short distance. Unless an external force is applied, cans will continue on the first turret and will not be attracted to the second turret. However, a feature of the invention is the employment of a movable diverter which functions to displace cans from their pockets in the first turret only a very short distance sufiicient merely to cause the cans to leave the field of magnetic Patented May 23, 1961 attraction of the first turret to be attracted by the mag nets in the second turret. In the embodiment of the in vention hereinafter illustrated, good cans are diverted fiom the first turret to the second turret by an oscillating diverted lever which is solenoid-actuated and diverts the cans the requisite distance (which may be as little as one-quarter inch) required to move the cans from the field of magnetic attraction of the first turret into the.

field of magnetic attraction of the second turret from which they are stripped off and deposited in a good can chute. On the other hand, in the hereinafter described embodmient, defective cans are not contacted by the diverter and hence are carried around by the first turret to a defective can discharge station where they are stripped 0E and deposited in a defective can chute.

Accordingly the present invention comprises a trans fer mechanism for switching cans from the first turret to the second turret wherein most of the force required to cause the cans to shift is supplied by the magnetic at traction of the permanent magnet located in the second turret and the initiation of the switching movement is con trolled by a diverter which requires only an extremely small amplitude of movement. In prior can switching mechanisms, swinging gates of various types have been used, many of which are solenoid-actuated, but the amplitude of swinging movement of the gates is much greater than that required of the diverter of this invention for the reason that in the prior art the gate must accomplish the full movement, whereas in the present invention the diverter need only initiate the movement and the completion of the movement is the result of the cans having moved from the field of magnetic attraction of the first turret into the field of magnetic attraction of the second turret.

The present invention provides a discharge mechanism which is extremely rapid in operation, as well as extremely sensitive, and yet the machine is relatively free from moving parts which may introduce elements of inaccuracy, likelihood of jamming the cans or retarding the speed of operation.

In addition, the present invention employs a switching means for switching cans from one turret to another which comprises a pair of turrets each having permanent magnets in their respective pockets, with a diverter selectively operable to divert selected cans only a sufiicient distance so that they leave the field of attraction of the magnets in the pockets of the first turret and enter the field of attraction of the magnets in the second turret, with the result that the second turret magnets complete the required shifting movement.

A further principal advantage of the present invention is the fact that because of the small movement of the diverter and further by reason of the light weight of empty cans, very high speeds may' be attained without sacrifice of accuracy of segregation of defective from perfect cans.

Another feature of the present invention is the fact that in the event the source of electric power should fail or there should be some failure in the circuitry, the machine will reject all cans rather than pass all cans. When the machine begins to reject all cans, the attendant is very soon aware of the situation and can shut down the machine for repair, whereas in prior constructions, when all cans are passed, the attendant is not aware of the situation and defective cans may be passed along with good cans.

Other objects of the present invention will become apparent upon reading the following specification and referring to the accompanying drawings in which similar characters of reference represent corresponding parts in each of the several views.

In the drawings:

Fig. 1 is a schematic viewshowing the elements of the present invention;

Fig. 2 is an enlarged fragmentary sectional view taken substantially along the line 22 of Fig. 1;

Fig. 3 is a side elevation of the memorizer wheel and associated mechanism; and

' Fig. 4 is a vertical sectional view taken substantially along the line 4-4 of Fig. 3.

Referring now to Fig 1, there is provided a can-tester wheel (not shown) of large diameter, the path of travel thereof being designated by dot and dash line 11 which intersects the path of travel of the smaller diameter discharge turret 12. A plurality of can pockets 13 which are disposed with their axes parallel to the horizontal axis of rotation of the tester wheel is located on the periphery of the can-tester wheel. Dot-and-dash line 11 represents a portion of the path of travel of the axis of such pockets. The construction of pockets 13- and the means whereby the covers 14 therefor are opened and closed and cans are inserted therein and removed therefrom form no part of the present invention and are well understood in the art to which this invention pertains. Essentially, however, such pocket 13 comprises an open-ended, cylindrical, pneumatically sealed receptacle dimensioned to receive therein a can 16 to be tested, with the open end 17 of the can facing toward the open end 18 of pocket 13. Each pocket 13 is provided with a cover 14 having on its inner surface a resilient gasket 19 which seals against end 18 of the pocket and also against the open edge 17 of the can, and ac cordingly seals the interior of the pocket from the atmosphere and the interior of the can both from the atmos phere and from the pocket. Compressed air is delivered to can 16 by means of a pipe 20, a suitable valve mechanism (not shown) being provided to initiate and discontinue delivery of compressed air at appropriate time intervals. A pipe 21 is attached to pocket 13 so that pressure within pocket chamber 13A is transmitted by pipe 21. If a normal or non-leaky can is disposed within pocket 13, the pressure within chamber 13A and hence within pipe 21 will remain substantially at atmospheric despite the pressure of the compressed air entering through pipe 21 and existing in the can. However, when a defective can is deposited in pocket 13, the compressed air in the can leaks out to chamber 13A and the increase in pressure is transmitted by pipe 21.

Pipe 21 leads to' valve mechanism 22 (the details of which are not illustrated since they are well understood in this art) and is in communication with one of a plurality of pipes 22 which terminate at one of a plurality of pressure-responsive detectors 24 which comprises a housing of two shallow halves 26 and 26 having their open ends facing each other and engaging around their lips the edges of a metal diaphragm 27. Diaphragm 27 is formed with annular corrugationZS so that it is particularly sensitive to pressure and deflects responsive to pressure differentials on its opposite surfaces. Pipe 2 2 is connected to housing 26 on one side of diaphragm 27 and housing 26 on the opposite side of the diaphragm is vented by means of vent 29. Pin 31 is fixed to diaphragm 27 and projects out of housing 26. As diaphragm 27 moves responsive to pressure in pipe 22, the movement is transmitted to pin 31. One lead'32 of an electrical system is connected to detector 24 and hence pin 31 comprises one element of a switch contact. The other element 32 of the switch contact is positioned in proximity to the end of pin 3-1. Hence, when the pressure in pipe 22* rises by reason of a leaky can being'deposited in a pocket 13, pin 31 completes an electric circuit to one of a plurality of solenoids 33-, the function of which hereinafter appears.

Memorizer wheel 34 is shown schematically in Fig. 1 V

and in greater detail in Figs. 3 and 4. The wheel revolves around shaft 36 and is fixed to gear 3 7 which meshes with pinion 38 on the shaft 39 of discharge turret 12. Surrounding wheel 34 is a frame 41. Although, as shown in Fig. 1, for the sake of simplicity, only a single solenoid 33 is illustrated, actually three

solenoids

33, 33 and 33 mounted on frame 41 and three detectors 24 are employed, one being associated with each solenoid. Thus every third pocket 13 is pneumatically connected by valve 23 with a proper detector 24. This arrangement enables detection to be carried out for three times the length of time which would be possible if there were a single detector. In proximity to each solenoid 33 is a T-shaped trip lever 42 which is pivoted about pivot 43. Pin 44 projecting upwardly from one branch of trip lever 42 contacts armature 46 of solenoid 33. Coil spring 47 which projects into recess 43 in the other arm of trip lever 42 and which is carried in an adjustable spring retainer 49 threaded into frame 41 biases trip lever 42 in a clockwise direction as viewed in Figs. 1 and 4. Thus when solenoid 33 is energized by a defective can being detected, armature 46 is retracted and trip lever 42 is moved by thrust of spring 48 through a small arc. The lower leg 51 of trip lever 42 is formed with a bevel 52 on its leading surface and engages and depresses one of a plurality of detents 53 carried by memorizer wheel 34.

Memorizer Wheel 34 is formed with three steps, 54 54 and 54, as best shown in Fig. 4, and each of the steps is formed with a plurality of radially extending holes 56 slidably receiving detents 53 which comprise short, smooth pins. Detents 53 are angularly spaced from one another. Each of the trip levers 42 is positioned and dimensioned so that it is associated with only one of steps 54*, 54 and 54 and engages only those detents in that particular step. Assuming, therefore, that a leaky can is deposited in a particular pocket 13 and that leg 51 of trip lever 42 has swung to the left as viewed in Fig. 4, as memorizer wheel 34 revolves, the next detent 53 in the particular step with which the trip lever is associated contacts beveled leading surface 52 of the trip lever and hence is depressed so that it is projected inwardly of the memorizer wheel, the opposite end projecting inwardly from the inside of flange 5-7.

Located on frame 41 approximately removed from trip levers 42 is switch lever 58 pivoted by means of horizontal pivot 59 to brackets 61 on frame 41. The upper end of switch lever 58 has a three-stepped finger 62 attached thereto formed with steps corresponding to steps 54 54 and 54 on flange 57. In the event that any of detents 53 is depressed by action of one of trip levers 42, when it is carried around to bottom position it contacts and moves finger 62 outwardly and pivots switch lever 58 outwardly. An extension 63 of switch lever 58 has a contact 64 which engages a microswitch 66 and microswitch 66 is connected into an electric circuit which energizes electromagnet 67.

Inorder to reset depressed detents 53, a three-stepped detent-resetting cam 68 is attached to frame 41 by arm 69 intermediate switch lever 58 and trip levers 42. Resetting cam 68 forces any depressed detents 53 into extended position prior to the time that they travel into proximity with trip levers 42. g

It is necessary that a certain time interval elapse between the time that a defective can is detected and it is diverted from the normal cans, this time interval being necessary in order to remove the can fromtesting pocket 13. Accordingly, the rnemon'zer wheel 34 is employed to record the fact that a defective can has been tested and preserves the recordation until after the can has been discharged from its pocket 13. Thertime interval between detection of the leaky can and the instant that it reaches the point of transfer from first discharge turret 12 to second discharge turret 91 is the same as the time interval between the time that detent 53 passes trip lever 42 and switch lever 58.

in order to afiord adjustability to the memorizer wheel,

gear 37 is connected to memorizer wheel 34 by means of bolts 71 which pass through arcuate slots 72 in memorizer wheel 34, thereby permitting adjustment of timing. In addition, the segment 73 on which switch lever 58 is mounted is connected to frame 41 by means of bolts 74 which also pass through arcuate slots 76. In addition, subframe 77 on which solenoids 33 and trip levers 42 are mounted is attached to frame 41 by means of other bolts 78 passing through arcuate slots 79. The adjustable mounting of the various parts of the memorizer wheel affords considerable adjustability in the timing of the functions thereof.

First discharge turret 12 comprises a hub 81 keyed to shaft 39 having spaced peripheral flanges 80 formed with a plurality of can-receiving pockets 82 in the shape of a common can transfer star wheel. Fastened to hub 81 in a pocket 81 at the bottom of each pocket 82 by means of screws 83 is a permanent horseshoe magnet 84 having a magnetic attraction sufficient to hold a can 85 in pocket 82 until it is either stripped off or diverted from the pocket. As hereinafter explained, good cans 85 are diverted from turret 12 onto turret 91, whereas defective cans 85 remain onturret 12 beyond the zone of transfer designated by reference numeral 92. Defective cans are released from individual pockets 13 at the completion of the testing cycle and are directed by means of curved stripper rails 86 into pockets 82 of star wheels 80 and carried around in a clockwise direction as viewed in Fig. l with magnets 84 functioning to assist in holding the same in the pockets. In those instances where the cans are defective, they are carried around past the point of transfer 92 to defective can chute 93 which comprises a top and

bottom rail

94 and 96, respectively, bottom rail 96 having an inward curved extension 97 which strips the cans out of their pockets against the force of magnets 84.

Second discharge turret 91 is mounted on a shaft 98 which is driven in synchronisrn with shaft 39. The two turrets are illustrated as overlapping over a portion of their peripheries, but it will be understood that this is not essential to their construction. Turret 91 comprises a hub 100 keyed to shaft 98 and having spaced peripheral flanges 99 formed with a plurality of can-receiving pockets 101 of the same shape as pockets 82. The spacing between star Wheels 99 is greater than that between star Wheels 80 to provide clearance where the turrets overlap. Fastened in recesses 95 at the bottom of each pocket 101 by means of screws 83 in the same manner as in the case of turret 12 is a permanent horseshoe magnet 102 having a magnetic attraction substantially the same as magnets 84. The spacing between the center lines of shafts 39- and 98 is such that at their closest point, which has been denominated the zone of transfer 92, the central axis of a can 85 in a pocket 82 of turret 12 is displaced toward the center line of shaft 39 a short distance of about inch, for example, as compared with the central axis of a can in pocket 101 of second discharge turret 91. Accordingly, unless physically moved from turret 12 to turret 91, the can will continue in turret 12 instead of being transferred to turret 91. However, only a slight movement of about /5 inch is necessary to move the can from the field of magnetic attraction of magnets 84 and into the field of magnetic attraction of magnets 102 and this factor is of considerable importance in the operation of the instant device.

On either side of

turrets

12 and 91 is a fixed side plate 103 in which shafts 39 and 98 are journalled. Mounted on one of plates 103 is electromagnet 67. The armature 104 of magnet 67 is attached by a slot and pin connection to lever 106 attached at its opposite end to shaft 107. Shaft 107 is journalled in boss 108 projecting inward from mounting plate 109 attached to side plate 103. An elongated slot 111 is formed in side plate 103 and slots 112 are formed in mounting plate 109. Bolts 113 passing through slots 112 secure mounting plate 109 to side plate 103. Slot 111 in side plate 103 and slots 112 in mounting plate 109 permit adjustment of the position of shaft 107 to accommodate cans of different diameters. On the inner end of shaft 107 is a short lever termed a diverter 114. By angular movement of shaft 107, diverter 114 may be turned to divert a can from turret 12 to turret 91 or to avoid such diversion. Hence the position of diverter 114 as controlled by solenoid 67 determines whether a can will be diverted from turret 12 to turret 91 or carried around by turret 12 to defective can discharge chute 93. On the opposite side of the machine is a short, fixed rail 116 held on righthand side plate 103 by bolt 117.

Good cans are stripped from turret 91 by rail 121 which comprises an extension of curved rail 86, as shown in the drawings. Cans thus stripped are deposited in good can chute 122 which is defined by rails 94 and 121.

Accordingly the instant invention provides an accurate leaky can detector 24 and a memorizer 34 which first records the fact that a leaky can has been tested and retains the information until the leaky can has been discharged from the tester wheel pocket 13 in which it was tested and transferred to the first discharge turret 12 and carried around to the zone of transfer 92 to the second discharge turret 91, whereupon a segregating device com prising an electromagnet 67 and movable diverter 114 either diverts the can from the field of magnets 84 and pockets 82 of turret 12 and into the field of magnet 102 of pocket 101 of magnet 91, or else refrains from such diversion, depending upon whether solenoid 67 is actuated. It will further be seen that the means of controlling transfer from the one turret to the other has utility in container handling machines other than can testing machines.

Although the foregoing invention has been described in some detail by way of illustration and example for pur poses of clarity of understanding, it is understood that certain changes and modifications may be practiced within the spirit of the invention and scope of the appended claims.

What is claimed is:

1. In a transfer mechanism for selectively switching an article, a first turret having a plurality of pockets each having at least one first magnet therein, a second turret having a plurality of pockets each having at least one second magnet therein, the paths of the centers of the pockets of said first and second turrets intersecting over a portion of their peripheries, said intersection forming a zone of transfer drive means for driving said turrets together and with pockets of each said turret occupying substantially the same space at said zone of transfer, a diverter movable between a first and second position disposed adjacent said zone of transfer, said diverter when in first position deflecting an article carried in the pocket of said first turret at said zone of transfer from the field of attraction of the first magnet out of said pocket of said first turret against the magnetic force of attraction of said first magnet to the field of attraction of the corresponding second magnet contained in a pocket of said second turret, whereby the magnetic force of said second magnet pulls said article into the pocket containing said second magnet, and means for moving said diverter between first and second positions selectively to deflect an article from said first turret into said second turret or to retain an article in said first turret.

2. In a transfer mechanism for selectively switching an article, a first turret having a plurality of pockets each having at least one first magnet therein, a second turret having a plurality of pockets each having at least one second magnet therein, the paths of the centers of the pockets of said first and sec-0nd turrets intersecting over a portion of their peripheries, said intersection forming a zone of transfer drive means for driving said turretstogether and with pockets of each said turret occupying substantially the same space at said zone of transfer, a diverter movable between a first and second position disposed adjacent said zone of transfer, said diverter when in first position deflecting an article carried in the pocket of said first turret at said zone of transfer from the field of attraction of the first magnet out of said pocket of said first turret against the magnetic force of attraction of said first magnet to the field of attraction of the corresponding second magnet contained in a pocket of said second turret, whereby the magnetic force of said second magnet pulls said article into the pocket containing said second magnet, a shaft onwhich said diverter is fixed, means mounting said shaft for oscillatory motion, a solenoid, means operable on energization of said solenoid for oscillating said shaft to move said diverter from first to second positions selectively to deflect an article from said first turret into said second turret or to retain an article in said first turret, and switch means controlling energization of said solenoid.

3. A mechanism according to claim 2 in which said means mounting said shaft is movable toward and away from one of said turrets.

4. In a can transfer mechanism for selectively switching a can, a first star turret having a plurality of first pockets each shaped to receive a can and a first permanent magnet tending to hold a can in its respective pocket, a second star turret having a plurality of second pockets each shaped to receive a can and a second permanent magnet tending to hold a can in its respective pocket, the paths of the centers of the pockets of said turrets overlapping in a portion of their peripheries, said intersection forming a zone of transfer, means for driving said turrets together and with pockets of each said turret occupying substantially the same space at said zone of transfer, said turrets being spaced apart a distance such that at said zone of transfer a can in a first pocket is closer to the axis of rotation of said first turret than a can in a second pocket, a diverter at said zone movable from a first position to deflect a can out of said pocket of said first turret against the magnetic force of attraction of said first magnet in said pocket from the zone of attraction of a first magnet into the zone of attraction of a second magnet contained in a pocket of said second turret, whereby the magnetic force of said second magnet pulls said can into the pocked containing said second magnet to a second position wherein said diverter is inoperative, and means for moving said diverter between first and second positions.

5. In a can transfer mechanism for selectively switching a can, a first star turret having a plurality'of first pockets each shaped to receive a can and a first permanent magnet tending to hold a can in its respective pocket, a second star turret having a plurality of second pockets each shaped to receive a can and a second permanent magnet tending to hold a can in its respective pocket, the paths of the centers of the pockets of said turrets asst-zoos overlapping i a portion of their peripheries, said intersection forming a zone of transfer, means for driving said turrets together and with pockets of each said turret occupying substantially the same space at said zone of transfer, said turrets being spaced apart a distance such that at said zone of transfer a can in' a first pocket is closer to the axis of rotation of said first turret than a can in a second pocket, a diverter at said zone movable from a first position to deflect a can out of said pocket of said first turret against the magnetic force of attraction of said first magnet in said pocket from the zone of attraction of a first magnet into the zone of attraction of a second magnet contained in a pocket of said second turret, whereby the magnetic force of said second magnet pulls said can into the pocket containing said second magnet to a second position wherein said diverter is inoperative, a solenoid, means operatively connecting said solenoid to said diverter to move said diverter between first and second positions, and switch means for energizing said solenoid.

6. A mechanism according to claim 5 wherein is provided mounting means for said diverter, said mounting means being adjustable to move said diverter toward and away from said first turret to accommodate cans of different diameters.

7. A mechanism according to claim 5 which further comprises testing means and means connected to said testing means to control said switch means.

- 8. A mechanism according to claim 5 which further comprises defective can detection means, a memorizer actuated by said detection means to record detection of a defective can and store recordation for a time interval, said memorizer being synchronized with the movement of said turrets, said switch means being actuated by said memorizer after said time interval to energize said solenoid to move said diverter.

References Cited in the file of this patent UNITED STATES PATENTS 2,013,402 Cameron Sept. 3, 1935 2,217,342 Ladrach Oct. 8, 1940 2,269,474 Nordquist Jan. 13, 1942 2,335,239 Gladfelter et a1 Nov. 30, 1943 2,353,758 Peck July 18, 1944 2,687,202 Nordquist et al Aug. 24, 1954 2,696,107 Blaing-Leisk Dec. 7, 1954 2,729,329 Pechy Jan. 3, 1956 2,743,001 Nordquist Apr. 24, 1956 2,821,300 Bofinger et al. Jan. 28, 1958 2,827,998 Breeback Mar. 25, 1958 2,868,373 Renard et al. Jan. 13, 1959