Abstract:
A continuous motion can decorator includes a plurality of mandrel subassemblies mounted on a rotating carrier with equal angular spacings between adjacent subassemblies. The assemblies reciprocate radially with respect to the carrier axis as a center. Each subassembly includes a radially extending support arm that mounts a radially extending mono rail which extends through guide bearing units on the carrier. The mandrel of each subassembly is mounted on an axis that is parallel to the rotational axis of the carrier. An eccentric type mounting is provided for the mandrel axle on the reciprocating arm so that there is an individually operated means to adjust spacing between the carrier rotational axis and the mandrel axis. Vacuum and pressurized air are fed selectively to each mandrel subassembly through a flexible hose having a single loop that is formed by curving virtually the entire length of the hose.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates generally to continuous motion high speed apparatus for applying decorations to cylindrical containers and in particular relates to improvements in mandrel carriers for apparatus of that type which is disclosed in U.S. Pat. Nos. 4,821,638 and 5,799,574. 
     Incorporated herein by reference are teachings of the aforesaid U.S. Pat. No. 4,821,638 which issued Apr. 18, 1989 to P.G. Uithoven for Apparatus Supporting and Printing Cylindrical Objects and U.S. Pat. No. 5,799,574 which issued Sep. 1, 1998 to R. Williams, C. Chrobocinski and A. C. Rodums for Spindle Disc for High Speed Can Decorators. Also incorporated herein by reference are the teachings of U.S. Pat. No. 3,766,851 issued Oct. 23, 1973 to E. Sirvet et al for Continuous Can Printer and Handling Apparatus, U.S. Pat. No. 4,140,053 issued Feb. 20, 1979 to J. Skypek et al for Mandrel Mounting and Trip Mechanism for Continuous Motion Decorator and U.S. Pat. No. 5,111,742 issued May 12, 1992 to R. DiDonato et al for Mandrel Trio Subassembly for Continuous Motion Can Decorators. 
     U.S. Pat. No. 5,799,574 discloses relatively high speed apparatus for applying decorations to the exterior of cylindrical containers while they are mounted on mandrels which are disposed along the periphery of a large continuously rotating disc-like carrier. Decorations are applied to the containers as they engage a rotating blanket of a decorator that is adjacent the periphery of the carrier. During engagement between the containers and the blanket, the containers track the blanket surface through the printing region where the containers and blanket surface are engaged. To accomplish this tracking, for each angular position of the container measured about the axis of the spindle disc as a center, a device controlled by a closed loop or box cam maintains the container in a precise radial position relative to the axis of the spindle disc. 
     This type of decorating equipment includes a number of relatively heavy elements that move at high speed. Because there must be precise coordination between the various elements, inertia forces, lubrication and operating power are significant engineering design considerations, as are equipment downtime, maintenance costs and setup procedures. 
     SUMMARY OF THE INVENTION 
     In accordance with the instant invention, each of the mandrels is part of an individual mandrel subassembly that includes a support arm which must, be relatively rigid in order to properly position the cantilevered mandrel while decorations are being applied to the container carried thereby. To accomplish this, in the instant invention the arm is relatively flat and is provided with a longitudinally extending rail that rides in a linear slide which directs the subassembly to reciprocate radially with respect to the rotational axis of the mandrel carrier. Sideways deflection of the subassembly arm relative to the mandrel carrier is limited by utilizing a roller type linear slide which has multiple groups of bearing elements that engage longitudinal bearing surfaces on the rail. Each bearing surface faces in a different direction and is engaged by a different group of bearing elements. Each bearing element is cylindrical and has a rotational axes that is transverse to the reciprocation path of the rail that is engaged by such element. 
     Positional integrity of the subassemblies relative to the carrier is maintained by providing shallow channels in the carrier to receive the slides, and shallow grooves in the support arms to receive an individual rail. Parallel channel arms fit tightly against the housing for the slide that is entered in the channel and arms forming the groove fit tightly against side surfaces of the rail. 
     To simplify setup and to increase the interval between setups, the axis of the spindle is eccentric with respect to the axis of the rear mounting section of the axle having the spindle at the front thereof. The mounting section is provided with an external cylindrical surface that is engaged by a matching internal cylindrical surface of a mounting hole in the subassembly arm at the radially outer end thereof. Thus, pivoting the axle about the mounting axis causes a change in spacing between the spindle axis and the carrier axis to control contact pressure between the cans and the printing blanket. Pivoting of the axle is accomplished by two adjusting screws, each of which is on the arm and extends inward of the internal cylindrical surface of the internal cylindrical surface to engage an individual ledge formed in the external cylindrical surface. With one screw backed away from its companion ledge, inward movement of the other screw forces the axle to pivot in a first direction, and by backing the other screw away from its companion ledge, inward movement of the one screw forces the axle to pivot in a direction opposite to the first direction. 
     Accordingly, the primary object of the instant invention is to provide an improved high speed continuous motion cylindrical container decorator having substantially reduced maintenance and/or power requirements. 
     Another object is to provide a decorator of this type wherein substantial cost and weight reductions have been achieved for the disc-like carrier and reciprocating mandrel subassemblies carried thereby. 
     Still another object is to provide a construction for this type of decorator to simplify setup procedures, extend periods of operation and reduce downtime for maintenance. 
     A further object is to reduce printing pressure requirements while maintaining print quality. 
     A still further object is to improve positional integrity between the mandrel carrier and moving elements of the mandrel subassemblies mounted on the carrier and reciprocating radially with respect to the rotational axis of the carrier. 
     Yet another object is to provide elongated roller-type linear slides to mount the reciprocating mandrel subassemblies on the carrier. 
     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 front elevation of continuous motion can decorating apparatus that includes a mandrel carrier assembly constructed in accordance with teachings of the instant invention. 
     FIG. 2 is a fragmentary cross-section of the mandrel carrier assembly taken through line  2 — 2  of FIG. 1 looking in the direction of arrows  2 — 2 . 
     FIG. 3 is a fragmentary front elevation of the mandrel carrier assembly looking in the direction of arrows  3 — 3  of FIG.  2 . 
     FIG. 4 is a rear elevation of the mandrel carrier and elements welded thereto. 
     FIG. 5 is a cross-section taken through line  5 — 5  of FIG. 4 looking in the direction of arrows  5 — 5 . 
     FIG. 6 is a front elevation of the assembly in FIG.  5 . 
     FIG. 7 is a fragmentary edge view of the mandrel carrier. 
     FIG. 8 is a front elevation of the support arm of a mandrel subassembly. 
     FIG. 9 is an elevation looking in the direction of arrows  9 — 9  in FIG. 8 at the radially outer end of the support arm. 
     FIG. 10 is a side elevation, partially sectioned, of the support arm looking in the direction of arrows  10 — 10  in FIG.  8 . 
     FIG. 11 is a cross-section taken through line  11 — 11  in FIG. 10 looking in the direction of arrows  11 — 11 . 
     FIG. 12 is a side elevation of an axle which includes a spindle section on which a mandrel is rotatably mounted. 
     FIG. 13 is an elevation looking at the rear end of the axle in FIG.  12 . 
     FIG. 14 is a side elevation of two elongated roller-type linear slides in operative engagement with a mono rail of a mandrel subassembly. 
     FIG. 15 is a front elevation of the elements in FIG. 14 looking in the direction of arrows  15 — 15  in FIG.  14 . 
     FIG. 16 is a schematic end view of a mono rail engaged with the rollers of a linear slide. 
     FIG. 17 is a fragmentary perspective illustrating an end portion of the mono rail partially engaged with a linear slide. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Now referring to the Figures and more particularly to FIG. 1 which illustrates continuous motion cylindrical container decorating apparatus of the general type described in the aforesaid U.S. Pat. Nos. 3,766,851 and 5,111,742. The apparatus of FIG. 1 includes infeed conveyor chute  15  which receives undecorated containers in the form of beverage cans  16 , each open at one end thereof, from a can supply (not shown) and places cans  16  in arcuate cradles or pockets  17  formed by aligned depressions in the outer edges of spaced segmented rings  31 ,  32  (FIG.  2 ). The latter are fixedly secured to support ring  33  that is positioned in front of and secured to disc-like mandrel carrier  18  on eight angularly spaced standoffs  48 . Screws  43  secure the segments of pocket rings  31 ,  32  to support ring  33 . 
     Carrier  18  is mounted on continuously rotating horizontal drive shaft  19  whose first end (toward the left in FIG. 2) is rotatably supported on a fixed portion of the frame of the decorating apparatus illustrated in FIG.  1 . Shaft  19  is drivingly connected to carrier  18  by key  45  that engages tapered sleeve  46  which is wedged between drive shaft  19  and hub  47 . The latter is welded to carrier  18  at the center thereof. 
     Horizontally extending mandrels  20  (FIG. 2) are also mounted to carrier  18 , with each mandrel  20  being in spaced horizontal alignment with an individual pocket  17  while passing through a short loading region extending downstream from infeed conveyor  15 . In this short region, undecorated cans  16  are moved horizontally rearward by a deflector (not shown), being transferred from each cradle  17  to an individual mandrel  20 . Suction applied through an axial passage  148  (FIG. 12) extending to the outboard or front end  21  a of spindle shaft  21  on which mandrel  20  rotates freely, draws container  16  rearward (to the left with respect to FIG. 2) to final seating position on mandrel  20 . 
     While mounted on mandrels  20 , cans  16  are decorated by being brought into engagement with continuously rotating image transfer mat or printing blanket  91  of the multicolored printing press decorating section indicated generally by reference numeral  22 . Thereafter, and while mounted to mandrels  20 , each decorated can  16  is coated with a protective film of varnish applied thereto by engagement with the periphery of applicator roll  23  in the overvarnish unit indicated generally by numeral  24 . Cans  16  with decorations and protective coatings thereon are then transferred from spindles  20  to suction cups (not shown) mounted near the periphery of transfer wheel  27  while the latter rotates about shaft  28  as a center. Cans  16  carried by transfer wheel  27  are deposited on generally horizontal pins  29  which project from chain type output conveyor  30  that carries cans  16  through a curing oven (not shown). 
     By the time mandrel  20  moves beyond the downstream end of chute  15  and is in the proximity of sensor  133 , each mandrel  20  should be properly loaded with a can  16 . If sensor  133  detects that a mandrel  20  is unloaded or is not properly loaded, then before this particular mandrel  20  enters the decorating zone wherein printing blanket  91  normally engages can  16  on mandrel  20 , this unloaded or misloaded mandrel  20  is moved to a tripped or “no-print” position relative to printing blanket  91 . As a tripped mandrel  20  moves through the decorating zone it will be spaced from the periphery of blanket  91 . This no-print position is achieved by controlling double acting cylinder  34  to trip subframe  35  having mandrel carrier shaft  19  mounted thereon, by moving subframe  35  to the left with respect to FIG. 1 while main base  36 , to which printing unit  22  is mounted, remains stationary. Further, actuation of sensor  133  causes overvarnish unit  24  to move downward with respect to mandrel carrying shaft  19  so that the tripped spindles  20  do not engage overvarnish application roll  23 . 
     Mandrel  20  is part of mandrel subassembly  40  that also includes support arm or base  41  (FIG.  8 ), shaft  44  (FIG.  12 ), rigid straight rail  51  and two cam follower rollers  57 ,  58 . Spindle  21  is the front portion of shaft  44  and extends forward from arm  41  near its radially outer end, being perpendicular thereto and parallel to carrier shaft  19 . Follower rollers  57 ,  58  are at the rear of arm  41 , being rotatably mounted on stub shaft  61  that projects from aperture  59  which extends through arm  41  radially inward of shaft  44 . Closed loop cam track  55  surrounds mandrel disc drive shaft  19  and receives followers  57 ,  58 . In a manner known to the art, cooperation of cam  55  and followers  57 ,  58  controls the radial spacings between the respective rotational axes  80 ,  85  defined by shaft  19  and spindles  21 , respectively. 
     With particular reference to FIGS.  8 - 11  it is seen that support arm  41  is an elongated member that is tapered lengthwise, being widest at its radially outer end where stub shaft  44  and cam follower rollers  57 ,.  58  are mounted. Aperture  71  in arm  41  is disposed radially outward of aperture  59  and is provided to receive mounting section  22  (FIG. 12) at the rear end of shaft  44 . The outer cylindrical surface  72  of shaft  44  to the rear of axle shoulder  73  is closely fitted to the inner cylindrical surface of aperture  71 . As will hereinafter be explained, shaft  44  is pivotable relative to arm  41  about the axis  74  about which surface  72  is formed. 
     Pressurized air and vacuum are selectively supplied to aperture  71  through L-shaped passage  81  whose outer end is connected through rigid stub pipes  82   a ,  82   b to fitting  82  (FIG. 2) at one end of flexible hose  83 . The inner end of passage  81  communicates with circular undercut  86  in mounting surface  72  of shaft  44  and transverse passages  87 ,  87  connect undercut  86  with passage  148  that extends axially through shaft  44  so that pressurized air and vacuum can be present at the forward end of spindle  21 . The end of hose  83  remote from fitting  82  is provided with fitting  84  that is connected through rigid stub pipe  85   a to supply passage  85  which extends through movable face valve member  75  that is connected to hub  47  for continuous rotation therewith. 
     Each airway between a passage  85   a and the outer end of a passage  81  consists of flexible hose  83  and rigid stub pipes  82   a ,  82   b ,  85   a . As seen in FIG. 2, the vast majority of the length of hose  83  is bent to form a single loop with very short portions of hose  83  being required to connect such single loop to pipes  85   a and  82   a ,  82   b . Further, the hose  83  is positioned so that no side portions thereof do not rub against other side portions thereof or rub against other elements of the apparatus. Hose life is shortened very quickly in the event hose  83  rubs against another element or portions of the hose rub against each other. 
     At its rear end  88   a , longitudinal passage  148  is enlarged and is provided with an internal thread that is engaged by retainer  188  which draws shoulder  73  against the front end of arm  41  to secure axle  44  to arm  41 . At its front end  88   b , longitudinal passage  148  is threaded internally to receive a screw (not shown) that retains mandrel  20  mounted on spindle shaft  21 . 
     Threaded apertures  78 ,  79  extend outward from aperture  71  and are positioned so that adjusting screws  76 ,  77  which extend through respective apertures  78 ,  79  are accessible for operation from outside of arm  41  to adjust the angular position of axle  44 . That is, when screws  76 ,  77  move inward through apertures  78 ,  79  the inner ends of screws  76 ,  77  engage respective ledges  88 ,  89  in surface  72 . To pivot axle  44 , say clockwise when looking at its front or spindle end, screw  76  must be backed away from ledge  88  and then screw  77  is turned inward against ledge  89  until axle  44  reaches a desired angular position by turning clockwise about mounting axes  74 . The latter is parallel to but slightly eccentric with respect to spindle axis  85  so that as axle  44  pivots the spacing between spindle axis  85   a nd axis  80  of mandrel carrier  18  changes. After the desired spacing between axes  80  and  85  is reached, screw  76  is turned inward against ledge  88  to lock axle  44  against pivoting about-mounting axis  74 . To pivot axle  44  counterclockwise, screw  77  is backed away from ledge  89 , then screw  76  is turned inward against ledge  88  to pivot axle  44  counterclockwise until spindle  21  reaches its required position, and then screw  77  is moved forward against ledge  79  to lock axle  44  against pivoting. 
     Now referring more particularly to FIGS.  5 - 8 , carrier  18  is a steel disc that carries twenty-four ( 24 ) mandrel subassemblies  40  that are in a generally circular array about carrier axis  80  as a center. The major portion of each subassembly is arranged to reciprocate radially with respect to axis  80 , being guided by the cooperation of mono rail  51  and a pair of aligned cylindrical roller-type bearing units or linear slides  90 ,  90  through which rail  51  extends. A suitable mono rail structure for the decorating apparatus of the instant invention is marketed by Schneeberger Inc., having a place of business located in Bedford, Mass. 01730 U.S.A. 
     Rail  51  (FIGS. 16 and 17) of such mono rail structure is an elongated member which includes rear wall  91  and short parallel sidewall sections  92 ,  92  extending forward from opposite ends of rear wall  91 . Located at each side of rail  51  and extending forward from each wall section  92  are a pair of flat longitudinal guide surfaces  93 ,  93 . Bearing elements  95  of two slide units  90  ride on each surface  93 . The pair of guide surfaces  93 ,  93  on the right of FIG. 16 are at right angles to each other and the rear one of this pair is at 45° with respect to right wall section  92 . Similarly, the pair of guide surfaces  93 ,  93  on the left in FIG. 16 are mirror images of the other pair  93 ,  93 . Thus, slide units  90 ,  90  lock rail  51  from pivoting clockwise or counterclockwise about the longitudinal axis of rail  51 . Each linear slide  90  includes four arrays  94  of bearing elements  95 , one for each rail surface  93 , with each bearing array being disposed to move along an individual raceway (not shown) which is formed in housing  180  of slide unit  90  so that, as seen in FIG. 17, a portion of each array is exposed to engage a rail surface  93 . 
     Unless precautions are taken to restrain bearing elements  95 , one or more of them can separate easily from base  180  and compromise the integrity of assembly between rail  51  and bearing units  90 ,  90 . Thus, retainer  201  (FIG. 8) is removably secured to the radially inner end of arm  41  to prevent separation between rail  51  of subassembly  40  and slides  90 ,  90 . That is, there will be interference between slides  90 ,  90  and retainer  201  so long as screw  202  secures retainer  201  in its operative position at the radially inner end of rail  51 . The enlarged radially outer end of arm  41  blocks removal of slides  90 ,  90  at the radially outer end of rail  51 . 
     Positional integrity of rail  51  relative to arm  41  is achieved by fastening screws  96  that extend through individual clearance apertures  103  in rail  51  and are received by individual threaded apertures  104  in arm  41 . Arm  41  also includes shallow longitudinal channel  102  (FIG. 11) defined by a pair of short parallel arms  101 ,  101  at the front of arm  41 . The short sidewalls  92 ,  92  of rail  51  enter channel  102  and are fitted tightly between arms  101 ,  101  which block guide rail  51  from movement about axes that extend at right angles to rear wall  91 . 
     Positional integrity of subassembly  40  is controlled to a great extent by rigidly positioning slide units  90 ,  90  on carrier  18 . More particularly, carrier  18  (FIGS.  4 - 7 ) is a steel disk having flat front surface  128  and rear surface  129  that is machined to form an individual shallow radial groove  125  for the pair of slides  90 ,  90  that guides each of the subassemblies  40 . For each groove  125 , carrier  18  is provided with eight clearance apertures  126  that are aligned with the respective threaded apertures  136  at the front of slides  90 ,  90  to threadably receive fastening screws (not shown) that extend through apertures  126 . For each groove  125 , carrier  18  is also provided with a pair of clearance apertures  127  that are aligned with respective openings  137  at the front of slides  90 ,  90 . Lubricant applied through apertures  127  to openings  137  lubricates the elongated bearing elements  140  of slides  90 ,  90 . Threaded mounting apertures  136  are in front wall  151  of slide  90 , which wall  151  is drawn against the bottom wall  152  of groove  125  and short side walls  153 ,  153  of groove  125  are fitted tightly against slide  90  with screws  203 . 
     Application of pressurized air and vacuum to hoses  83  is under the control of a face-valve arrangement that includes stationary valve elements  199  mounted at the front of stationary frame member  99  and rotating wear plate  198  having apertures aligned with one end of channels  85  in hub attachment  75 . 
     Each of the four longitudinal bearing faces  93  of rail  51  is in sliding engagement with an individual partial array of bearing elements  95  of two slides  90 ,  90 , so that rail  51  is constrained to reciprocate radially. Each of the bearing elements  95  is cylindrical with a length transverse to bearing face  93 , that is greater than the diameter of the elements  95 . The cylindrical surfaces of elements  95  are parallel to each other and extend crosswise with respect to the length of bearing faces  93  which they engage. 
     For each slide  90 , each of the four bearing element arrays occupies an individual raceway  191  in the housing  180  of slide  90 . The bearing elements  95  of the partial array are disposed with their cylindrical axes in a plane that is parallel to the bearing face  93  with which the partial array is engaged. 
     Although the present invention has been described in relation to particular embodiments thereof, many other variations and modifications and other uses will become apparent to those skilled in the art.