Background of the Invention
1. Field of the Invention
The present invention relates generally to transfer mechanisms and methods for cylindrical articles, and more particularly to a synchronized transfer mechanism for moving newly formed cans from a forming ram to a work station, such as a trimmer.
2. Description of the Prior Art
Production of thin wall drawn and ironed metal cans involves drawing of a cup of the metal, which may be, for instance, steel or aluminum, into an elongated can configuration and then ironing by means of dies to produce very thin walls. As a result of this process, the upper portion of the can is open and of uneven length while the bottom portion of the can is closed with an integral bottom. The uneven upper portion must be trimmed to produce a can body of uniform height prior to further processing steps.
As a rule, the cans are ejected axially from the ram by, for instance, air pressure and/or stripper fingers and fed into a chute. The chute serves as an accumulation volume and the trimmer is conventionally operated in nonsynchronous fashion. However, since the walls of the can are thin and fragile, and since the height of the can varies, the newly formed cans are difficult to transport with chute arrangements. An example of a chute or hopper feed is shown in Gladfelter et al, U.S. Pat. No. 2,298,366 and Windstrup, U.S. Pat. No. 3,548,769. Once the can is presented to the processing station in, for instance, an in-feed chute, it is often necessary to synchronize the feed of the cans with the work station such as by the screw feed shown in Cvacho et al, U.S. Pat. No. 3,756,103.
Thus, the prior art generally accumulated the newly formed cans in chutes or hoppers and provided the work station with an independent, unsynchronize supply which had to be resynchronized with the machine. The shortcomings and drawbacks of this approach was recognized in Langewis, U.S. Pat. No. 3,864,995. Instead of utilizing an accumulation area between the can forming machine and work station, this more recent teaching utilized an indexing star-wheel conveyor which stops in a position aligned with the end of the forming ram, receives a newly formed can, and rapidly accelerates the can into a work station. However, at the high line speeds involved, the indexing of the star-wheel involves substantial acceleration and requires a relatively complex drive to synchronize the stopping and starting star-wheel with the motion of the forming ram.
While not entirely appropriate for the purposes of the instant invention, Spain, U.S. Pat. No. 828,865 discloses a feed mechanism in which articles are dropped radially into a vertical wheel mechanism in which a full circle enclosure opens and closes symmetrically to receive the falling articles.
Summary of the Invention
The present invention, which provides a heretofore unavailable improvement over previous synchronized feed mechanisms and methods, comprises a continuously rotating wheel structure having defined therein a plurality of pockets which, during a portion of the wheel structure movement, are aligned with and adjacent to the body forming ram. The pockets are formed of movable sections which may be opened and closed independently of each other. Further, the pockets are synchronized with the ejection of the newly formed can from the ram whereby the leading edge of the pocket initiates closing preferably as soon as it passes the volume occupied by the can as it enters the pocket. Thus the relative movement between the rotating pocket and newly inserted can is minimized as the leading edge of the pocket moves towards the can and largely counters the rotational movement of the wheel. Thereafter, the trailing edge of the pocket closes around the can to accurately locate the can in the pocket. The constantly rotating wheel is driven in synchronous with the ram to, at one position, present an open pocket for each can ejected from the ram and, at another position, to provide a can to a work station such as a trimmer.
Accordingly, an object of the present invention is to provide a new and improved method and apparatus for synchronously feeding cans from a can body maker to a work station.
Another object of the present invention is to provide a new and improved method and apparatus for axially feeding cans into a constantly rotating wheel structure by means of movable sections forming pockets in the wheel structure.
Yet another object of the present invention is to provide a new and improved method and apparatus for transferring cans which has a fail-safe positive displacement of the pocket sections in the critical interface with the forming ram.
Still another object of the present invention is to provide a new and improved method and apparatus for processing cans in which a can former, a can trimmer and an interfacing transfer means are commonly driven in a constant and synchronous manner.
These and other objects and features of the present invention will become apparent from the following description.
Brief Description of the Drawing
In the drawing
FIG. 1 is a simplified perspective view of a transfer apparatus, in accord with the present invention, with a body maker and work station.
FIG. 2 is a more detailed axial view of the transfer apparatus shown in FIG. 1.
FIG. 3 is an enlarged partial view of a pocket portion of the instant invention in a closed figuration;
FIG. 4 is an enlarged partial view of an open pocket portion of the apparatus in accord with the instant invention configured to receive a newly formed can;
FIG. 5 is an enlarged partial view of a pocket portion of an apparatus in accord with the present invention upon initially receiving a can in the pocket;
FIG. 6 is an enlarged partial view of a pocket portion of an apparatus in accord with the present invention which is transporting a can in a fully closed configuration;
FIG. 7 is a sectioned view of a pocket; and
FIG. 8 is an enlarged, partial view of the transfer mechanism in accord with the instant invention wherein a can is being transferred to a work station.
Detailed Description of the Invention
Turning now to the drawings, wherein like components are designated by like reference numerals throughout the various figures, a transfer device for synchronously conveying cans between a can body maker and a work station is illustrated in FIG. 1 and generally designated by reference numeral 10. In conjunction with transfer mechanism 10, body maker 12 and work station 14, form an integrated, synchronized combination for forming and processing cans. Ram 16, driven by the prime mover (not shown) of body maker 12, is forced through forming dies 17 to produce a can body having an upper portion of uneven length. Power take-off 19 from body maker 12 and associated bevel gears 20 and 21 drive shaft 22 which in turn, through reduction gears 24 and 25, drive main shaft 26 of work station 14. At the other end of main shaft 26, drive wheel 28, driven wheel 31 for transfer mechanism 10, and idler wheels 30 and 32 form, in conjunction with belt 34, a serpentine drive which, as shown, causes drive wheel 28 and driven wheel 31 to rotate in opposite directions. In this manner, work station 14 is driven by means of reduction gears 24 ultimately driven by power take-off 19 as a direct mechanical linkage to body maker 12. Preferably, the drive means between body maker 12 and work station 14 reduces the drive speed as a function of the number of individual stations in work station 14 relative to the number of articles formed by body maker 12 per revolution of power take-off 19. Similarly, the ratio of speeds between transfer mechanism 10 and work station 14 is controlled by the relative sizes of drive wheel 28 and driven wheel 30, and are again a ratio of the number of stations in transfer means 10 relative to the number of stations in work station 14.
In operation, a can 48, shown in FIG. 2, is formed by the movement of ram 16 through forming dies 17 in a conventional manner and removed from ram 16 by stripper means 36 while a pocket 40 of transfer means 10 is adjacent the end of ram 16 as a result of the synchronous continuous movement of transfer means 10 as will be described in more detail below. Also, as a result of the synchronous, serpentine drive of transfer means 10 and work station 14, a pocket 40 interfaces with a station routine. At all times, transfer mechanism 10, body maker 12 and work station 14 are driven in a continuous and synchronous manner by fixed ratio, positively interlocked drive means.
The manner in which a continuously driven wheel structure 42 having a plurality of pockets 40 defined therein operates to receive an axially delivered can 48 will be more readily understood with reference to FIGS. 2 through 7. For purposes of clarity and to illustrate various modes of operation, the wheel structure 42 illustrated in FIG. 2 rotates in a counter-clockwise direction as viewed while that illustrated in FIG. 1 operates in a clockwise direction. Further, the position of transfer between transfer mechanism 10 and work station 14 in FIG. 1 has been altered somewhat for purposes of this illustration. As shown in FIG. 2, wheel structure 42 is supported for rotation on concentric shaft 50. A plurality of movable pockets 40 are supported on wheel structure 42. More particularly, pockets 40 are formed of first articulated section 58 and second articulated section 59 joined together by central pivot 60. Each pocket 40 is normally biased into a closed position by means of spring members 62 and 63 attached to first section 58 and second section 59 respectively.
Each of the articulated sections 58 and 59 carry a roller cam follower 65 and 66 respectively. Thus, while spring members 62 and 63 normally urge articulated sections 58 and 59 into a closed configuration, lobes 68 and 69 of cam surfaces 52 and 54 displace cam followers 65 and 66 to open sections 58 and 59 at preselected portions to positively open pocket 40 to receive can 48. Even in the event spring members 62 and 63 fail, sections 58 and 59 of pocket 40 will be open to receive a can 48 from ram 16.
Thus as shown in FIG. 3, springs 65 and 66 normally maintain first and second movable sections 58 and 59 of pocket 40 in a closed position with cam followers 65 and 66 riding on cam surfaces 52 and 54 respectively. However, as shown in FIG. 4, as first and second movable sections 58 and 59 approach the position at which can 48 is ejected into pocket 40, roller cam followers 65 and 66 ride up raised lobes 68 and 69 of cam surfaces 52 and 54 thereby opening movable sections 58 and 59 to receive can 48. Open pocket 40 more than adequately provides room for can 48 to enter pocket 40 while pocket 40 moves with wheel structure 42. As first movable section 58 passes the point of interference with can 48, as shown in FIG. 5, roller cam follower 65 descends the ramp portion of lobe 68 thereby initiating the closing of first movable section 58 independent of the movement of second movable section 59 which is maintained in the open configuration by cam follower 66 on lobe 69. Thus, with first movable section 58 closing, the relative movement between can 48 and first movable section 58 is minimized. When, as shown in FIG. 6, can 48 is fully within pocket 40, both first and second movable sections 58 and 59 are completely closed as a result of both roller cam followers 65 and 66 beig supported by cam surfaces 52 and 54 at other than the location of raised lobes 68 and 69. Can 48 is firmly held within closed pocket 40 and guiderails 71 and 72 and end plates 74 and 75 for transport, as shown in FIG. 7, with rotation of wheel structure 42.
At the point of transfer between transfer mechanism 10 and work station 14, pocket 40 comes into register with receiving means 77 of work station 14. Both pocket 40 and receiving means 77 constitute essentially a half circle (or somewhat less) support of can 48. Guiderail 80 serves to move can 48 out of pocket 40 as both transfer means 10 and work station 14 rotate in synchronous as described with reference to FIG. 1. Thus, can 48 is delivered in a positive, synchronous manner from body maker 12 through transfer means 10 to work station 14. At all times, as a result of the interlocking of the three mechanisms, the can is transferred in a synchronous manner.
Once deposited at receiving means 77 and secured between receiving means 77 and guiderail 80, can 48 is further processed in accord with the prior art, or any other desired manner. As described above, transfer from body maker 12 to work station 14 is accomplished without resort to accumulation hoppers and without loss of synchronization. Further, the transfer is accomplished using constantly rotating wheel structure 42.
Although but one embodiment of the present invention has been illustrated and described, it is anticipated that numerous changes and modifications will be apparent to those skilled in the art and that such changes may be made without departing from the invention, as defined by the following claims.