Patent Publication Number: US-4928511-A

Title: Rotary cup infeed

Description:
BACKGROUND OF THE INVENTION 
     This invention relates to cup infeeders and more particularly relates to a continuously rotating feeder which transports cups to a receiving station where the cups are indexed for engagement by a reciprocating tool that moves parallel to the axis of rotation for the rotating feeder 
     The main section or body of a so-called two piece metal container includes an elongated cylindrical sidewall, an integral bottom and an open top. Such bodies are often formed in drawing and ironing machines of the type described in the E. Paramonoff, U.S. Pat. No. 3,704,619 issued Dec. 5, 1972 and U.S. Pat. No. 3,735,629 issued May 29, 1973 entitled, respectively, Redraw Blankholder positioning Mechanism for Cup-Shaped Article Formers Such as Metallic Can Body Formers and the Like and Apparatus for Forming One Piece Metallic Can Bodies. Such machines produce can bodies from blanks, in the form of shallow cups, by having a reciprocated ram drive each cup through a die pack which is a series of die elements having openings that are graduated so that the blank passes through the largest opening first and each subsequent opening that the blank is driven through is slightly smaller than the preceding opening through which the blank has been driven. 
     In prior art apparatus of this type the cups are transferred from a gravity feed chute to a receiving station through which the ram travels. A linearly reciprocated feed element is disclosed in U.S. Pat. No. 4,534,202 issued Aug. 13, 1985 to W. W. Snyder for Cup Feeding Mechanism, and a pivoted feed member is disclosed in U.S. Pat. No. 4,061,012 issued Dec. 6, 1977 to E. F. Wessman for a Drawing and Ironing Machine With Positive Cup Feeder. 
     Utilization of reciprocated and/or rocking type feed mechanisms severely limits production rates of prior art machines and often presented maintenance problems. 
     SUMMARY OF THE INVENTION 
     The instant invention overcomes the limitations which linearly reciprocated and rocking type feed mechanisms imposed on prior art drawing and ironing machines by providing a feed mechanism that comprises a single continuously rotating arm having a pocket that receives a blank as it is gradually lowered from a feed chute by a lead-in surface that extended into the pocket. The feed member positively moves the cup along an arcuate guide and into a receiving station where the blank is positioned for engagement by the ram as it moves forward in its working stroke. A stationary stripper removes the blank from the pocket upstream of the receiving station means but the feed member continues to positively drive the blank to engagement with registry means at the receiving station. When the blank engages the registry means a portion of the feed member cooperates with the registry means to hold the blank in registered position until it is engaged by the ram and/or by a movable clamping pad that reciprocates in association with the ram. 
     OBJECTS OF THE INVENTION 
     Accordingly, the primary object of the instant invention is to provide a continuously rotating mechanism for feeding blanks to a receiving station through which tool means operates. 
     Another object is to provide feeding means of this type that is adapted for a drawing and ironing machine which transforms metal cups into one piece can bodies. 
     Still another object is to provide a feeder of this type that rotates through a complete revolution for each operation of a reciprocated ram that engages a workpiece which is delivered by the feed member after being released by the latter. 
     A further object is to provide a feed mechanism of this type having means that cooperates with registry means to hold a blank in position for engagement by a tool. 
     A still further object is to provide a feed mechanism of this type which limits abrupt movement of the blanks that are disposed within a gravity feed chute. 
     These objects as well as other objects of this invention shall become readily apparent after reading the following description of the accompanying drawings in which: 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective of a cup-shaped article forming machine incorporating the continuous rotary feed mechanism constructed in accordance with the instant invention. 
     FIG. 2 is an enlarged fragmentary somewhat diagrammatic view of the die pack section in the machine of FIG. 1 looking in the direction of arrows 2--2 of FIG. 1 with the ram and redraw blank holder pad in their forward or can body forming positions. 
     FIG. 3 is an enlarged rear elevation of the rotary feed mechanism. 
     FIG. 4 is a cross-section taken through line 4--4 of FIG. 3 looking in the direction of arrows 4--4. 
     FIG. 5 is an enlarged fragmentary horizontal section showing the ram and blank holder pad of the tool means retracted prior to engagement with a blank. 
     FIG. 6 is a cross-section taken through lines 6--6 of FIG. 5 looking in the direction of arrows 6--6 with the blank holder pad in its forward clamping position 
     FIGS. 7, 8 and 9 are simplified rear elevations of the rotary feed mechanism showing various positions for a blank as it leaves the gravity feed chute (FIG. 7) until it is in engagement with the registry means at the receiving station and disposed for engagement by the movable tool elements (FIG. 9). 
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENT 
     Now referring to the Figures. Rotary feed mechanism 10 (FIG. 3) of this invention is incorporated in otherwise conventional drawing and ironing machine 11 of FIG. 1. The latter includes main frame 20 having main drive mechanism 22 mounted thereon for reciprocating ram 24 (FIG. 2) along a horizontal feed path from a rearward reversing position (FIG. 5) forwardly through receiving station 25 of feeding mechanism 10, the forward direction being from right to left with respect to FIG. 2. Forward of feeding mechanism 10 ram 24 passes through die pack 28 and, upon reaching the position illustrated in FIG. 2, reverses and returns to the position illustrated in FIG. 5. 
     Body former 11 receives shallow cup-shaped blanks 30 that are disposed side-by-side in gravity chute 26. Blanks 30 exit one at a time from the bottom of chute 26 and are transformed into elongated one piece can bodies 32 (FIG. 2). That is, the cylindrical sidewall of cup 30 is elongated and ironed by passing through a series of ring-shaped dies 33a-33d, being driven into ram 24. During initial forward movement of ram 24 in its working stroke, ram 24 is preceded by blank holder pad 34 (FIGS. 5 and 6). The latter is mounted to movable bend holder frame assembly 98 positioned in front of cross-arm 99 of main frame 20. As assembly 98 moves forward relative to cross-arm 99 from its return or retracted position of FIG. 5 to its clamping position of FIG. 6, pad 34 enters blank 30 through its rear facing open end thereof (FIG. 6) and clamps bottom 31 of blank 30 against the first die ring 33a. Then ram 24 moves through assembly 98 including central guide bore 35 of pad 34, engages bottom 31 and drives it forward through die rings 33a- 33d and finally into engagement with doming formation 36 (FIG. 2). 
     With particular reference to FIGS. 3, 4 and 7 through 9, it is seen that feed mechanism 10 includes rotary feed member 40 that is keyed to continuously rotating horizontal shaft 41 The periphery of feed member 40 is disposed to move below and in proximity to the bottom or exit end of chute 26. Blank 30 shown in phantom in FIG. 3 is positioned at the bottom of chute 26 for removal through the exit thereof. At this time blank 30 is supported by lead-in surface portion 40a along the edge of feed member 40. Lead-in surface portion 40a is so shaped that while it supports can 30 as the latter gradually moves downward through the exit of chute 26 Finally, blank 30 is received in pocket 40b (FIG. 7) of feed member 40 and is driven along the upper main arcuate portion 42 of guide wall 43. The lower or terminal portion 44 of guide wall 43 is generally straight and generally parallel to edge 46 of stripper 45. Narrow slot 51 (FIG. 4) in the edge of rotating feed member 40 provides clearance for stripper 45. When blank 30 moves between guide portion 44 and edge 46, stripper 45 forces blank 30 out of pocket 40b. However, feed member 40 continues to drive blank 30 downward until it reaches receiving station 25 where arcuate indexing or registry formation 48 arrests movement of blank 30 in a position aligned with ram 24 and clamping pad 34 (FIG. 5). While clamping pad 34 moves from the rear position of FIG. 5 to the clamping position of FIG. 6, edge portion 40c of member 40 that extends immediately upstream from pocket 40b locks blank 30 against registry formation 48 (FIG. 9). 
     Edge portion 40c which constitutes a holding means, is the part of feed member 40 that is most distant from the rotational axis thereof, and shaft 41 is positioned so that no portion of member 40 passes across the feed path of ram 24. This means that the latter cannot engage feed member 40 in the event these elements are out of synchronization. 
     In the event of a malfunction, solenoid operated plunger 55 (FIG. 3) is actuated to extend into feed chute 26 and stop blanks 30 from moving therethrough 
     While rotary feed member 40 is a single lobe element having a single pocket 40b, it is noted that in the absence of size considerations a multilobed, multipocketed feed member may be provided so long as its rotational speed is coordinated with the reciprocating motion of ram 24 and clamping pad 35. The single lobe construction illustrated is appealing in that the feed member 40 and movable tool elements 24 and 35 operate on a one to one basis. That is, for each complete revolution of feed member 40 tool members 24 and 35 move forward and rearward through a complete cycle. 
     The power to rotate shaft 41 of feed member 40 is supplied by main drive 202 (FIG. 4) which is connected through clutch 203 and a timing belt 204 to normally rotate sprocket 205 that is keyed to shaft 41. When feed member 40 engages blank having an oval sidewall or other defect that causes it to wedge against guide wall 43, the force required to rotate feed member 40 increases. When this required force exceeds a predetermined value the driving connection broken between the input 206 and output 207 of clutch 203 whereby the driving connection between main drive 202 and feed member 40 is broken so that the latter ceases to deliver blanks to receiving station 25. 
     A braking force is applied automatically to clutch output 207 when the forward or working stroke of ram 24 fails to produce a properly formed elongated can body 32. For example, when a blank 30 has a defective sidewall, it is not uncommon for the front of blank 30 to separate from the remainder (rear) of blank 30 as ram 24 moves forward with this remainder of blank 30 remaining at the receiving station 25 to interfere with entry of the next blank 40 into station 25. More particularly, when ram 24 reaches the end of its forward stroke sensor 208 (FIG. 2) determines whether cam body 32 is defective by detecting if its sidewall is too short. If this defect condition is found to exist sensor 208 generates a signal which actuates brake 209 which applies an overboard force to clutch output 207. This breaks the driving connection between clutch input 206 and clutch output 207 so that the driving connection between main drive 202 and feed member 40 is broken. 
     Since the rotating feed member 40 has relatively low inertia the braking force applied to clutch output 207 coupled with removal of driving power from the latter causes feed member 40 to stop very quickly, say approximately a half cycle. Because the reciprocating ram 24 has relatively high inertia, it takes much longer to stop, say approximately one and a half cycles after driving power is removed therefrom and a braking force is applied thereto However, this failure of ram 24 to stop instantaneously does not cause additional damage. That is, for a second time ram 24 will merely pass through the rear portion of blank 30 that was left behind at receiving station 25. 
     Although the present invention has been described in connection with a plurality of preferred embodiments thereof, many other variations and modifications will now become apparent to those skilled in the art. It is preferred, therefore, that the present invention be limited not by the specific disclosure herein, but only by the appended claims.