Rotary valve controlled apparatus for stripping cans from bodymaking ram

#This invention relates generally to can bodymaking equipment and in particular relates to stripping of newly formed can bodies from the ram that drives the can forming blank through the forming dies.

#In the art of bodymaking apparatus for transforming blanks in the form of relatively short metal cups into elongated bodies for two piece cans, the bodies are stripped from the ram by mechanical devices that engage the edge at the open end of the body and/or by utilizing compressed air that enters the can body through one or more outlets at the downstream end of the ram. Mechanical strippers by themselves have been found to be unreliable, especially at high production speeds. Problems have also arisen at high production speeds when application of compressed air for stripping is under the control of valves that are mounted in the ram at its downstream end to be actuated by sensing that formation of the can body base profile has been completed. The prior art has also controlled application of compressed air for stripping by utilizing solenoid actuated valves that are mounted on the machine frame in a stationary position. Because solenoid valves are relatively slow to recycle, it is difficult to meet high cycle rate requirements. Air-line supply contaminates add to this problem. While solenoid valves can be shielded from much machine vibration, the total effect of slow recycling and contaminates is that solenoid valve operation becomes erratic at high cycle rates, making it difficult to maintain, adjust and/or control coordination between the position of the ram and the application of compressed air for stripping.

#Examples of can body strippers are disclosed in U.S. Pat. No. 3,524,338 issued Aug. 18, 1970 to J. S. Bozek for A Stripping Punch; U.S. Pat. No. 3,572,271 issued Mar. 23, 1971 to E. C. Fraze for Fabrication Of Can Bodies With Integral Bottom Walls; U.S. Pat. No. 3,771,344 issued Nov. 13, 1973 to G. W. Wright for Apparatus For Stripping Container Bodies From Metal Working Punches; and U.S. Pat. No. 5,056,350 issued Oct. 15, 1991 to B. A. Moen, W. R. Williams, B. E. Johansson and L. W. Mayer for Apparatus And Method For Stripping A Workpiece From Supporting Device.

#Other features and advantages of the present invention will become apparent from the following description of the invention which refers to the accompanying drawings.

#FIG. 1 is a perspective of a can bodymaker that includes body stripping apparatus constructed in accordance with teachings of the instant invention.

#FIGS. 2 and 3 are schematics of the bodymaker of FIG. 1 looking in the direction of arrows 2--2 in FIG. 1. In FIG. 2 the ram of the bodymaker is in its most rearward position after having completed its return stroke and in FIG. 3 the ram is in its most forward position after having completed its working stroke.

#Now referring to the Figures and more particularly to FIGS. 1 through 5 which, for the most part, are also found in U.S. Pat. No. 4,173,138 which issued Nov. 6, 1979 to R. M. Main and E. Paramonoff for a Can Bodymaker Having Improved Ram Support and Drive. The teachings of U.S. Pat. No. 4,173,138 are incorporated herein by reference.

#In a manner known to the art of making metal beverage containers, can bodymaker 15 transforms blanks in the form of shallow metal cups 16 (FIG. 2) delivered by infeed device 17 into elongated can bodies 18 (FIG. 3) which drop downwardly and are received by outfeed device 19. This is accomplished by utilizing reciprocating drive mechanism 20 to move horizontally disposed hollow ram 25 longitudinally forward in a working stroke from its rearmost position of FIG. 2 to its most forward position of FIG. 3, at which point movement of ram 25 is reversed and ram 25 moves in a return stroke to its most rearward position of FIG. 2. During its forward working stroke, ram 25 drives cup 16 through ring die assembly 22 which reduces the diameter and sidewall thickness of blank 16 while elongating same to form can body 18. During the forward and rearward movement, ram 25 is supported by spaced stationary bearing sleeves 23 and 24.

#Driving mechanism 20 is connected to the rear of ram 25 by bearing slide assembly 35 (FIG. 5). The latter is pivotally connected to the front end of drive rod 36 whose rear end is pivotally connected to the free upper end of drive arm 37, and the lower end of drive arm 37 is fixed to the machine frame at pivot center 38, so as to oscillate thereabout. Arm 37 is driven by transfer arm 39, one end of which is connected by pivot 41 to crank arm 43 and the other end of which is pivotally connected at 42 to drive arm 37 at a point intermediate the ends thereof. Pivot 41 is at the free end of crank arm 43 which extends radially from main shaft 44 and is keyed thereto for rotation thereby. Bull gear 40 is also keyed to main shaft 44 for rotation therewith, and is in mesh with pinion 46 that is keyed to drive shaft 47 which is driven by electric drive motor 48 through variable speed drive 49.