Abstract:
An apparatus for reshaping a container includes a number of reprofiler rollers supported by a mounting block that allows the rollers to travel along a circular path lying in a plane perpendicular to an axis along which the mounting block can be driven by a tooling ram. The mounting block and reprofiler rollers are rotated about the axis by a tooling drive shaft that is supported within the tooling ram. Removable spacers are provided between the reprofiler rollers and the mounting block and between the tooling drive shaft and the mounting block in order to provide a way of adjusting the radial and axial positions respectively of the rollers.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an apparatus and method for forming containers, and more particularly, an apparatus and method for reshaping the outer surface of the bottom end of a container which has been formed of aluminum or other metal. 
     2. Related Art 
     U.S. Pat. No. 4,768,672 describes a drawn and ironed container or can having a reduced neck around an upper end and a bottom profile which allows nesting with a similar container having such a reduced neck. As stated in U.S. Pat. No. 4,768,672, which is herein incorporated by reference, the use of such reduced neck cans has allowed a considerable savings in metal used by manufacturers of such cans. 
     U.S. Pat. No. 4,885,924 shows a method of reshaping a container having a side wall and a bottom wall, the container being rotated by support means while a roller is applied to the outer periphery of the bottom of the container and moved towards the container axis. The movement of the roller towards the container axis reshapes a transition wall connecting the side and bottom walls of the container. 
     The apparatus of U.S. Pat. No. 4,885,924 requires the movement of a work roller radially with respect to the longitudinal axis of a container body, and therefore requires the movement of the work roller in a direction perpendicular to the direction of a force applied to the container for holding it in position during the operation. This requirement creates vibration flowing from the complexity of movements and the mechanism so as to limit the maximum speed of operation and cause difficulty in timing the various operations in a high speed container reshaping machine. 
     SUMMARY OF THE INVENTION 
     The primary object of the present invention is to provide a new and improved method and apparatus for reshaping the end of a container. 
     In addition, the present invention is provided with a means for easily adjusting the diameter of the annular ring on the bottom of a reprofiled container in order to allow for stacking of the reprofiled container on similar containers with a variety of reduced neck diameters. 
     A first embodiment of the present invention includes a plurality of substantially identical processing stations. Each of these processing stations includes two facing turrets, namely, a tool turret and a feed turret. The tool turret has a plurality of circumferentially spaced tooling rams, each of which has a rotating, spinning head upon which are mounted four reprofiler rollers. The other of the facing turrets has a plurality (equal to the number of tooling rams) of circumferentially spaced can push rams each of which is in alignment with a respective tooling ram. A transport starwheel, which may or may not include vacuum can retaining means, is fixed between the two facing turrets and rotates in synchronism with them. Additionally, infeed and outflow starwheels are provided radially outwardly from said main starwheel and provide means for quickly and effectively transferring can bodies to and from the main vacuum starwheel between the two facing turrets. Details of a method and apparatus for transferring can bodies to and from the plurality of identical processing stations are described in pending U.S. patent application Ser. No. 08/069,006, (hereinafter referred to as the &#34;Bowlin et al.&#34; application) filed May 28, 1993, which is incorporated herein by reference since such means are used in the preferred embodiment of the present invention. 
     Each can is transported into a working position aligned with a tooling ram by the starwheel. A can push ram is then actuated by a push ram drive cam to engage the aligned can to move it axially toward the tooling ram by pushing the can axially toward the reprofiler rollers on the tooling ram. When the can push ram has reached its full stroke, the can which is still on the starwheel is in work position to be reprofiled. The tooling ram then is moved toward the can by a tool drive cam, bringing its spinning head with the reprofiler rollers orbiting the can axis and moving into contact with the outer periphery of the can base. Continued advancement of the reprofiler rollers causes the rollers to more forcefully engage the can base and reform it inwardly while making a number of orbits about the can before they are retracted back to their original position. The push ram retracts and the starwheel moves the can forward to its next position. 
     The reprofiler rollers are all mounted &#34;out of synch&#34; at different angles to each other to prevent the formation of four dents in the can when they initially come into contact with the can base. 
     Thus, the first embodiment of the present invention includes each tooling ram having a plurality of reprofiler rollers; a roller mounting block for supporting the rollers to travel along a predetermined circular orbital path in a plane perpendicular to the mounting block axis and having a center of curvature positioned coextensive with the can axis; a tooling drive shaft which is connected to the roller mounting block and rotates the roller mounting block about its axis coextensive with the can axis; with a tooling ram subassembly moving the mounting block axially along the central axis toward or away from the can. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention is better understood by reading the following Detailed Description of the Preferred Embodiments with reference to the accompanying drawing figures, in which like reference numerals refer to like elements throughout, and in which: 
     FIG. 1 illustrates a fragmentary view of one of the processing stations of the present invention; 
     FIG. 2 is a cross-sectional view of a tooling ram; 
     FIG. 3 is an end view of the tooling ram taken along line 3--3 of FIG. 2 showing the four reprofiler rollers mounted to the mounting block; 
     FIG. 4 is a cross-sectional view of one of the reprofiler rollers taken along line 4--4 of FIG. 2; 
     FIG. 5 is an exploded perspective view of the connection between the mounting block and the tooling drive shaft; 
     FIG. 6 is a transverse section taken through the ball bearing supporting one end of the tooling drive shaft; 
     FIG. 7 is a partial end view of the vacuum star wheel and showing three tooling rams circumferentially spaced in a single tool turret; 
     FIG. 8 is a partial side view taken in the direction of arrows 8--8 in FIG. 7; and 
     FIG. 9 is a partial side and sectional view of a second embodiment of the invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In describing preferred embodiments of the present invention illustrated in the drawings, specific terminology is employed for the sake of clarity. However, the invention is not intended to be limited to the specific terminology so selected, and it is to be understood that each specific element includes all technical equivalents which operate in a similar manner to accomplish a similar purpose. 
     FIG. 1 shows a portion of one of a plurality of identical processing stations 15, each of which is mounted on a radial extension 16 of a horizontal main support shaft 210 which is supported for rotation on a fixed frame (not shown) and driven in the manner of shaft 110 of the Bowlin et al. application incorporated herein by reference. A tool drive ram assembly 22 is shown activated by reactive engagement of cam followers 56 with a fixed cam 57 (FIG. 7) so that reprofiler rollers 76 are pressed against the bottom of a can 102 which is held in position between the tool drive ram assembly 22 and a can push ram 100 by a conventional starwheel 300 which can optionally be a vacuum starwheel if desired. Can push ram 100 is mounted for reciprocation in a slide bushing 101. Cam followers 103 on the outer end of ram 100 engage a fixedly positioned cam 104 so that rotation of shaft 210 causes reciprocation of push ram 100. 
     The tool drive ram assembly 22 has a first end 28 and a second end 36 as shown in FIG. 2. First end 28 of tool drive ram assembly 22 is substantially cylindrical in shape and has a central axial bore 24 passing therethrough. Ram assembly first end 28 is connected to ram assembly second end 36 by an intermediate connecting portion 44 and machine screws 45. 
     Cam followers 56 are secured to ram assembly second end 36 by cam follower retainer nuts 58. Cam followers 56 move along the surface of fixed cam 57 as the tooling ram turret, is rotated about is center support means. Movement of cam followers 56 along this cain surface causes tool drive ram assembly 22 to reciprocate along a central axis passing through ram assembly first end 28 toward and away from vacuum star wheel 300 and a can 102 thereon. End 28 of tool drive assembly 22 is concentrically and slidably received within an axial bore 26 in a slide bushing 20. Slide bushing 20 is also substantially cylindrical in shape and has a first end 32 and a second end 30. The outer periphery of tool drive ram assembly first end 28 matingly fits closely to the inner surface of bore 26 of slide bushing 20. A smooth fit between slide bushing 20 and the tool drive ram assembly 22 is ensured by the presence of grease applied to their mating surfaces through grease fitting 60, and sealed against escaping from the space between their mating surfaces by oil seals 62 provided at each end of slide bushing 20. 
     As shown in FIG. 2, a tooling drive shaft 38 is concentrically and rotatably mounted within ram assembly first end 28. Tooling drive shaft 38 is located within ram assembly central axial bore 24 and has a first end 40 and a second end 42. As shown in FIG. 2 and FIG. 6, tooling drive shaft first end 40 is rotatably supported in ram assembly first end 28 by an angular contact type ball bearing assembly 200, which allows the transmittal of axial thrust forces from ram assembly 22 to a reprofiler roller mounting block 70. Inner race 200b of ball bearing assembly 200 rests against a pivot base shim 72 which separates inner bearing race 200b from an annular shoulder 73 on the mounting block 70. Tooling drive shaft second end 42 is supported in tooling ram assembly 22 by a self-aligning type ball bearing assembly 204. Self-aligning ball bearing assembly 204 is separated from a shoulder 47 in ram assembly 22 by &#34;Belleville&#34; washers 46. Self-aligning ball bearing assembly 204 compensates for any minor misalignments between tooling drive shaft 38 and tooling ram assembly 22 and applies pre-load force to bearing 200. 
     As shown in FIG. 2, a pinion drive gear 52 is keyed to tooling drive shaft second ,end 42. Pinion drive gear 52 is held on tooling drive shaft second end 42 by a bearing lock nut 54. Pinion drive gear 52, along with each of the pinion drive gears provided on the other tooling ram assemblies in a single turret is engaged with a single large stationary central bull gear 53 (FIG. 8) as shown in the Bowlin et al. application, which is incorporated herein by reference. Tooling drive shaft 38 is rotated by the orbital rotation of pinion drive gear 52 around fixedly positioned bull gear 53 and, as described in further detail below, rotates reprofiler roller mounting block 70. 
     As shown in FIG. 5, tooling drive shaft first end 40 has two circumferentially spaced, axially extending tangs 40a and 40b. These tangs are spaced 180° apart from each other, and extend axially from an annular shoulder at the tooling drive shaft first end 40. A blind bore 41 extends axially inwardly from first end 40 of tooling drive shaft 38. Blind bore 41 is internally threaded for threaded engagement with a mounting block retainer screw 78 as shown in FIG. 2. 
     Mounting block 70 also has two circumferentially spaced, axially extending tangs 70a and 70b. Tangs 70a and 70b are spaced 180° apart from each other and intermesh or interleave with tangs 40a and 40b of the tooling drive shaft 38 when mounting block 70 is connected to tooling drive shaft 38 by screw 78 as shown in FIG. 2. Mounting block screw 78 is seated in an axially extending counterbore 79 of mounting block 70. The threaded portion of screw 78 engages with internally threaded blind bore 41 of tooling drive shaft 38. 
     At an axial end of mounting block 70 opposite from axially extending tangs 70a and 70b, four reprofiler roller mounting shafts 82 are supported in radially extending bores that pass from the outer periphery of mounting block 70 through to central axial counterbore 79. The central axes of mounting shafts 82 lie in a plane perpendicular to the central axis of mounting block 70. Mounting shafts 82 are also circumferentially spaced non-equal distances such that none of the mounting shafts are in axial alignment as will be apparent from FIG. 3. Mounting shafts 82 are fixed in their radially extending bores by set screws 90 as shown in FIG. 4. 
     Each mounting shaft 82 supports a reprofiler roller 76 which is spaced from the outer periphery of mounting block 70 by a reprofiler roller spacer 74. Reprofiler rollers 76 are mounted for rotation on mounting shafts 82 by ball bearings 84. Ball bearings 84 are retained on the radially outer portions of mounting shafts 82 by bearing retainer washers 85 and bearing retainer screws 86. This arrangement allows for a quick and efficient replacement of spacer 74 when a spacer having a different thickness dimension is desired. Adjustment of the radius of the circular orbital path traveled by reprofiler rollers 76 is thereby facilitated by replacing the spacer with another spacer of different thickness, and the resultant profile of processed cans is easily and accurately controlled. 
     FIGS. 7 and 8 illustrate a cycle of operation showing three can positions a, b and c (a can is not shown in the position between positions a and b since it would obscure the can in position a). After a can 102 has been brought into position c for processing, it is held in position by starwheel 300, the can push ram 100 is activated to move the bottom end of can 102 into a position facing, but closely spaced from, rollers 76 as in position b and rollers 76 are moved axially toward can 102 by the cooperation of cam followers 56 with stationary cam 57. Reprofiler rollers 76 are brought into engagement with the bottom of can 102 at position a at a relatively slow pace, and are free to rotate about their axes. The reprofiler rollers orbit the axis 39 of tooling drive shaft 38 as a result of the rotation of tooling drive shaft 38. On an average, after making full contact with the bottom of a can, reprofiler rollers 76 will traverse 2-3 complete revolutions around the can while being moved toward the can to progressively increase contact with the can before being retracted axially away from the can. The last complete revolution of the rollers 76 around the bottom of can 102 serves to iron out any dents created upon initial contact between rollers 76 and the can 102. The likelihood of the creation of dents in the cans upon initial contact with rollers 76 is reduced by the rollers being offset relative to each other as shown in FIG. 3. 
     Tooling drive shaft 38, and therefore mounting block 70 and rollers 76, are continuously rotated by pinion drive gear 52, which is always meshed with the fixedly positioned large central bull gear 53. Therefore, rollers 76 continue to traverse a closed path and orbit the axis 39 of tooling drive shaft 38 even as tooling assembly 22 is moved axially into and out of contact with can 102. Tangs 70a and 70b of mounting block 70 in engagement with tangs 40a and 40b of tooling drive shaft 38, ensure that tooling drive shaft 38 will not become separated from mounting block 70, regardless of the direction of rotation of tooling drive shaft 38. Upon completion of the can working, ram 100 is retracted to the left and rollers 76 are retracted to the right to permit outfeed of the can from starwheel 300. 
     In addition to providing a means for transmitting axial thrust from tool drive ram assembly 22 to mounting block 70, pivot base shim 72 provides an additional means for adjusting the axial position of reprofiler rollers 76 by the use of shims having different thicknesses as will be apparent from inspection of FIG. 2. This feature makes the apparatus more adaptable for use with cans of varying height dimensions with changeover from one can size to another being quickly and easily accomplished. 
     FIG. 9 illustrates a second embodiment of the invention in which the reprofiler rollers are not moved into contact with the can but are instead held in a stationary position and the can is moved against the rollers with the can being concurrently rotated. More specifically, four reprofiler rollers 76&#39; are mounted on the inwardly facing end of a ram 100&#39; which is identical to ram 100 with the exception of the fact that ram 100&#39; does not have a can push member but instead provides support for the reprofiler rollers 76&#39;. Ram 100&#39; is mounted for reciprocation in bushing 101 and such reciprocation is effected by the reaction of cam followers 103 with the fixedly positioned cam 104&#39; in a manner analogous to the operation of the first embodiment. 
     The second embodiment includes a spinning push pad attached to the first end 40 of drive shaft 38 in exactly the same manner that the reprofiler roller mounting block 70 is attached to shaft 38 in the first embodiment. The spinning push pad includes first and second tangs identical to tangs 70a and 70b of the first embodiment which engage the tangs 40a and 40b on the end of shaft 38. 
     In operation, the whole assembly rotates with shaft 210 and cam 104&#39; moves the ram 100&#39; into facing relationship to the bottom of can 102 but closely spaced therefrom. Reaction of cam followers 56 with cam 57&#39; moves rotating shaft 38 to the left so that spinning push pad 110 engages a can and urges it against the reprofiler rollers 76&#39; while concurrently rotating the can about its axis so that there is relative movement between the can and the reprofiler rollers 76&#39; which merely rotate about their own individual axes but which do not orbit the axis of ram 100&#39; in the manner that roller 76 orbits the axis of block 70. Upon completion of the reforming of the can bottom, the reprofiler rollers 76 are moved to the left from their FIG. 9 position and the spinning push pad 110 is moved to the right from its FIG. 9 position so as to permit discharge of the can away from the turret 300. Thus, the second embodiment operates by rotating the can while holding the reprofiler rollers 76&#39; for rotation in a fixed position. The axes of the rollers on opposite sides of the ram 100&#39; can be aligned with each other or can alternatively be unaligned in the manner analogous to the mounting of the rollers 76 of the first embodiment. 
     Modifications and variations of the above-described embodiments of the present invention are possible, as appreciated by those skilled in the art in light of the above teachings. For instance, means other than a starwheel could be used for feeding and holding cans during the processing of cans. Also, the timing of operations can be varied so that, for instance, a can push ram would move a can axially towards a respective tooling ram and into contact with orbiting reprofiler rollers mounted on the tooling ram as in the first embodiment during the reprofiler operation, rather than the tooling ram moving the reprofiler rollers into contact with the can. Also, the reprofiler rollers do not have to be &#34;out of synch&#34; with each other but could be spaced 90° apart. 
     It is therefore to be understood that, within the scope of the appended claims and their equivalents, the invention may be practiced otherwise than as specifically described. 
     16 - radial extension 
     20 - slide bushing 
     22 - tool drive assembly 
     24 - tool drive assembly central axial bore 
     26 - slide bushing inner diameter 
     28 - tool drive assembly first end 
     28P - outer peripheral surface of 28 
     30 - slide bushing second end 
     32 - slide bushing first end 
     36 - tool drive assembly second end 
     38 - tooling drive shaft 
     39 - axis of tooling drive shaft 
     40 - tooling drive shaft first end 
     40a - tooling drive shaft first tang 
     40b - tooling drive shaft second tang 
     41 - blind bore 
     42 - tooling drive shaft second end 
     44 - ram assembly intermediate connecting portion 
     45 - machine screws 
     46 - Belleville washer 
     47 - ram assembly shoulder 
     48 - ram bushing cut-out portion 
     50 - pinion drive gear spacer washer 
     52 - pinion drive gear 
     53 - bull gear 
     54 - bearing lock nut 
     56 - cam follower 
     57 - cam 
     58 - cam follower nut 
     60 - grease fitting 
     62 - oil seal 
     70 - reprofiler roller mounting block 
     70a - reprofiler roller mounting block first tang 
     70b - reprofiler roller mounting block second tang 
     72 - pivot base shim 
     73 - mounting block shoulder 
     74 - reprofiler roller spacer 
     75 - reprofiler roller profile 
     76 - reprofile roller 
     78 - mounting block screw 
     79 - mounting block counterbore 
     82 - reprofiler roller mounting shaft 
     84 - mounting shaft bearing 
     85 - bearing retainer washer 
     86 - bearing retainer screw 
     90 - mounting shaft set screw 
     100 - can push ram 
     102 - can 
     200 - angular contact ball bearing assembly 
     200a - angular contact bearing balls 
     200b - angular contact bearing inner race 
     200c - angular contact bearing outer race 
     204 - self-aligning type ball bearing assembly 
     300 - vacuum starwheel