GB1591882A

GB1591882A - Continuous can printer and discharge apparatus and method

Info

Publication number: GB1591882A
Application number: GB5320477A
Authority: GB
Original assignee: Coors Container Co
Current assignee: Coors Container Co
Priority date: 1977-12-21
Filing date: 1977-12-21
Publication date: 1981-07-01

Description

(54) CONTINUOUS CAN PRINTER AND DISCHARGE APPARATUS AND METHOD (71) We, COORS CONTAINER COM- PANY, a Corporation organised and existing under the laws of the State of Colorado, United States of America, of 1755 West 32nd Avenue, Golden, State of Colorado 80401, United States of America, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to a method and means for discharging cylindrical cans in a printing machine. The major elements of such printers comprise infeed mechanism, loading means for placing cans on mandrels, a printing blanket wheel for transferring an image from the blanket cylinder to a container, and transfer mechanism for moving decorated cans to pins of a chain conveyor for passage through a curing and dryingoven.

Infeed mechanisms heretofore have comprised a star wheel for delivering cans successively to a pocket wheel, as in U.S.

3261,281; or have comprised a combination of elements, namely, a star wheel and a screw conveyor, as in U.S. 3766,851. The infeed mechanism carried cans to a pocket or cradle wheel provided with pockets for holding cans in axial alignment with mandrels on a mandrel wheel. Pockets or cradles disclosed in the aforementioned patents are either retractable in radial directions or movable in axial directions to carry cans to mandrels. The mechanism shown in U.S.

patent No. 3016,153 employs push rods moving in axial directions to place cans on mandrels and also for transferring decorated cans from the mandrels to a pin chain conveyor. In the prior art constructions, the infeed means utilized various moving parts, and the discharge means employed double cams and complex mechanisms for transferring decorated cans to a pin chain conveyor.

The invention relates to a continuous can printer incorporating a transfer wheel for transferring decorated cans from the mandrels of a pocket mandrel wheel, to discharge conveyor, wherein the transfer wheel comprises: (a) a hub driven in time with the mandrel wheel about an axis substantially parallel to the axis of the mandrel wheel, (b) a shaft carried by the hub, the direction of the axis of the shaft having a radial component and an axial component relative to the axis of the hub, (c) a suction cup assembly slidably mounted for movement along the shaft, (d) means for moving the suction cup assembly along the shaft, so as to track a part of the path of a mandrel on said mandrel wheel bearing a can, and (e) means for displacing the can from the mandrel to the suction cup, (f) means for applying a vacuum to the suction cup over a predetermined portion of transfer wheel rotation, so as to accept the can from the mandrel and to hold the can on the suction cup during the portion of transfer wheel rotation and for breaking the vacuum at the end of the portion of rotation to release the can to a discharge conveyor.

In preferred embodiments the invention provides an apparatus of this kind having an infeed means devoid of a star wheel, screw conveyor, and other moving parts.

Preferably the discharge conveyor is a chain conveyor having pins for receiving cans from the transfer wheel.

Preferably the means for moving the suction cup assembly on the shaft comprises a single cam cooperating with a cam follower connected to the suction cup assembly.

Preferably the suction cup assembly comprises a sleeve slidably moulted on the shaft and directly carrying a vacuum head and suction cup, a housing is mounted on said sleeve and a link is provided pivotally connected at one end to the hub and at the opposite end to the housing and having a coupling pivotally mounted between the said ends and connected to the cam follower for transmitting motion of the cam follower to the link, whereby motion of the cam causes motion of the suction cup assembly along the shaft.

Preferably the cam is so contoured as to produce all the radial component of the motion of the suction cup assembly necessary to cause the cup to track the part of the path of the mandrel.

Preferably the printer includes also a can infeed track for guiding cans under force of gravity from a supply to a rotatable pocket wheel having pockets on its circumferential surface, said track approaching the wheel in a nonradial path and forming an oblique angle with a tangent to the wheel at the intersection of the track and the wheel in the direction of wheel rotation, the track having an outlet portion that curves in the direction of wheel rotation and extends down to the depth of the pockets to redirect the path of the cans closer to the path of the pockets moving with the wheel; said pocket wheel having continuously adjacent pockets on its surface, each pocket having a leading and a trailing surface, the leading surface being smoothly contoured to recede under the path of a can entering the pocket from the track as the wheel rotates, without substantially interfering with the gravity induced motion of the can, said trailing surface contoured in an arcuate segment to seat the can and move it away from the infeed track with the rotation of the wheel when the can is fully in the pocket.

A continuous can printer having such an infeed track is described and claimed in Application No. 80/12569 which is divided from the present application. (Serial No.

1591883).

Preferably the pocket wheel further comprises a mandrel axially aligned with each pocket for receiving the can from the pocket and supporting the can during contact with a rotatable printing blanket cylinder for decorating the can exterior; a vacuum source in each mandrel for drawing the can onto the mandrel; and a flexible spring element mounted adjacent the pocket wheel and contacting each can seated in the pocket to urge the can axially in the pocket, toward the adjacent mandrel, while said vacuum is applied through the mandrel to draw and seat the can on the mandrel.

Preferably, the means for displacing the can from the mandrel to the suction cup comprises a controllable supply of compressed air connected to direct air through the mandrel, the mandrel having an air passage thercthrough.

The invention includes a method of discharging cans in a continuous can printer which method comprises: transferring cans from a rotating pocket mandrel wheel to a discharge conveyor by moving a suction cup assembly, which is slidably mounted on a shaft carried by the hub of a transfer wheel, the hub having an axis substantially parallel to the axis of said pocket mandrel wheel, to track the path of a mandrel bearing a can, the direction of axis of the shaft having both an axial and a radial component relative to the axis of said hub, displacing the can from the mandrel to the suction cup at the beginning of the tracking of the mandrel by the suction cup, applying vacuum through the suction cup over a predetermined portion of transfer wheel rotation to hold the can on the cup, and breaking the vacuum holding the can to release the can to a discharge conveyor.

The invention also includes a method of printing cans which method comprises feeding cans successively in a guided path by gravity directly to pockets mounted on and stationary with respect to a rotating pocket mandrel wheel in positions axially opposite mandrels on the wheel, contacting each can successively with a flexible spring member after the can enters a pocket to guide the can to the opposite mandrel, applying a vacuum to the mandrel to draw and seat the can onto the mandrel, printing the can on the mandrel and transferring the cam from the mandrel by the above described method.

In preferred embodiments of the invention, cans are conveyed directly from a conventional supply line to a chute through which cans fall by gravity into pockets of a pocket wheel. The pockets on the peripheral surface of the pocket wheel are contoured to received cylindrical cans and are stationary relatively to the wheel but are carried bodily with the wheel when it is rotated. Cans in the pockets are axially opposite mandrels mounted on the wheel referred to hereinafter as a pocket mandrel wheel. A spring shoe contacts the closed end of each can as it leaves the chute and this, combined with vacuum applied through the mandrel opposite each can, draws and seats the can on the mandrel.

Rotation of the pocket mandrel opposite each can, draws and seats the can on the mandrel.

Rotation of the pocket mandrel wheel carries the cans irito contact with the blanket cylinder. Just before printing contact, the end of the can mandrel is contacted by a pre-spin belt which brings the can up to surfacc speed of the blanket cylinder to ensure precisely matched speeds.

In the accompanying drawings which illustrate a specific embodiment of the invention, Fig. 1 is a front elevational view of a can printing machine embodying the invention.

Fig. 2 is a sectional view of one of the transfer stations whereby decorated cans are transferred from a pocket mandrel wheel to suction cups on a transfer wheel.

Figs. 3 and 4 are sectional views of a transfer vacuum head showing valving details.

Fig. 5 is a fragmentary elevational view of part of the infeed means.

Fig. 6 is a top view of the container load area of Fig. 1, on an enlarged scale.

Fig. 7 is an elevational end view, on an enlarged scale, of the means for transferring decorated cans to a pin chain.

As shown in Figure 1, cans 10 are cylindrical, provided with one closed end and an opposite open end. The cans are fed from a conventional track system to an inclined infeed chute 11 through which they move by gravity. The chute is provided with guide rails 12,13, and top guide 14. Cans pass into pockets 15 of a pocket mandrel wheel 16.

As the wheel is rotated past the infeed chute, the can rolls down the profiled infeed guides and contoured pocket surface until it is fully seated in the pocket 15. There are no moving parts to wear, and correct infeed timing is accomplished by the pocket and its contour. The closed end of each can is contacted by a spring shoe 17 which guides the can toward a mandrel 18 on wheel 16.

Vacuum is applied through the mandrel 18 and, with the guiding aid of the spring shoe 17, draws and seats the can on the mandrel 18 opposite the open end of the can. Rotation of the pocket mandrel wheel 16 in clockwise direction carries the can into contact with the printing blanket cylinder 19 where the image is transferred to the can 10.

Just before the printing contact, the end of the mandrel 18 is contacted by a pre-spin belt 20 on rollers 21 which brings the can on the mandrel to surface speed of the blanket cylinder 19. The belt is wrapped around and is driven by the blanket cylinder 19 to ensure precisely matched surface speeds.

The rollers 21 maintain tension on the belt 20. Ink is transferred to the blanket cylinder by inkers and plate cylinder 22. Four such inking stations are used in this machine.

Decorated cans are transferred from the pocket mandrel wheel 16 to suction cups on the transfer wheel 24. The transfer area is indicated at 25 on Fig. 1.

Fig. 2 shows one of the transfer stations.

The transfer wheel 24 consists of 24 stations to ensure adequate time for transfer. The hub 30 is locked to a cantilevered shaft 31 which is driven in time with the pocket mandrel wheel 16. The flange 32 of the wheel hub 30 carries an angled slide shaft 33 secured by shoulder 34 and screw and washer 35 in bore 36. A housing 37 is slidably carried by sleeve portion 38 on shaft 33 and in turn carries vacuum head 40 and screw 41. The opposite end of the head 40 carries a rubber bumper 42 and rubber suction cup 43. Link 44 is pivotally attached to the housing 37. A scalloped hub portion 45 carries a pivotally mounted arm 46 which carries a pair of cam follower rollers 47 supported on shaft 48. The opposite end of the shaft 48 carries a coupling 49 pivotally attached to the link 44. The followers 47 ride in box cam 50 which is secured against rotation by shaft support hub 51. Rotation of hub 30 causes cam followers 47 to ride up and down the swells of cam 50, thus rotating arm 46. Movement of this arm causes link 44 to pivot through coupling 49 and slide housing 37 down shaft 33, thus displacing suction head 40 in both axial and radial direction.

To transfer the decorated can 10 from the mandrels 18 to the transfer wheel 24, the can is blown off the mandrel 18 onto the suction cup 43 of the transfer suction head 40 where it is held by vacuum. Vacuum is applied to cup 43 through passages 52, 53 in said head, passages 54 and 55 in shaft 33, passage 56 in hub 30, a chamber 57, passage 58 in hub 30, and rotary valve 59 connected to a source of vacuum. The rotary valve 59 is screwed into an end plate 60 bolted to hub 30 to form chamber 57. This chamber acts as a vacuum manifold, thereby placing a large volume of vacuum as close to the vacuum head 40 as possible.

During the transfer operation, cam follower 47 follow the path of the box cam 50 and cause link 44 to pivot in a counterclockwise direction, thereby causing housing 37 to slide down shaft 33. The resultant radial motion of the cup 43 causes it to take a path coinciding with the path of the mandrel 18. At the beginning of this common path, in the transfer area 25, air is blown through the mandrel to displace the can from the mandrel to the cup. The resultant axial motion of the cup removes the can completely clear of the mandrel. During this time, vacuum is applied to the suction head 40 through passages 54, 54a and 54b and through passages 53 and 52 to suction cup 43. Bushings 62 and 63 seal vacuum in this position.

As the can on the transfer wheel comes into the unloading area, the contour on cam 50 causes housing 37 to slide further down shaft 33. As the head 40 reaches unload point 65, vacuum passage is blocked by bushing 62. As housing 37 continues to retract, cut out 61 on shaft 33 straddles bushing 63, thereby venting passage 53 to atmosphere and breaking vacuum. At this point the pin chain 66 carries the can off the suction cup and on through the oven for drying.

As best shown on Fig. 5, the pockets 15 in the peripheral surface of the rotating wheel 16 have a leading surface which slopes gradually downwardly to a can seating surface limited by a circular surface corresponding in cross section to a segment of the can circumference.

The use of the illustrated apparatus comprises feeding can successively from a supply source directly to said stationary pockets 15 of the rotating pocket wheel 16 in a guided path by gravity, said infced means and pockets being free of moving parts. The wheel has a mandrel opposite each pocket. Spring means contact each can when it enters a pocket to start the can to move axially onto the mandrel while vacuum is applied through the mandrel, drawing and seating the can on the mandrel. The can is printed while held on the mandrel. After printing, the decorated can is blown off the mandrel onto a suction cup on a suction head which is part of a transfer assembly on a rotating transfer wheel. Movement of the suction head and cup radially downwardly on an angled shaft mounted on said rotating trans fcr wheel movcs the cup in a path coinciding with the path of the mandrel, and blowing air through the mandrel at the beginning of the coinciding path displaces the can from the mandrel to the suction cup where it is held by vacuum.

Movement of the suction cup and head further down on the anglcd shaft blocks vacuum passage, rclcases the can from the cup and plaices it on a pin of a chain convcyor. All motion of the housing 37 carrying the vacuum head and cup 43 is in a radial and axial direction, accomplished by a single cam action.

WI-lAT WE CLAIM IS: l. A continuous can printer incorporat- ing a transfer wheel for transferring decorated cans from the mandrels of a pocket mandrel wheel by discharge conveyor.

wherein the transfer wheel comprises: (a) a hub driven in time with the mandrel wheel about an axis substantially parallel to the axis of the mandrel wheel, (b) a shaft carried by the hub. the direction of the axis of the shaft having a radial component and an axial component relative to the axis of the hub, (c) a suction cup assembly slidably mounted for movement along the shaft.

(d) means for moving the suction cup assembly along the shaft, so as to track a part of the path of a mandrel on said man drcl wheel bearing a can, and (e) means for displacing the can from the mandrel to the suction cup, (f) means for applying a vacuum to the suction cup over a predetermined portion of transfer wheel rotation. so as to acccpt the can from the mandrel and to hold the can on the suction cup during the portion of transfer wheel rotation and for breaking the vacuum at the end of the portion of rotation to release the can to a discharge conveyor.

2. A printer as claimed in claim 1 wherein the discharge conveyor is a chain conveyor having pins for receiving cans from the transfer wheel.

3. A printer as claimed in claim ] or claim 2, wherein the means for moving the suction cup assembly on the shaft comprises a single cam cooperating with a cam follower connected to the suction cup assembly.

4. A printer as claimed in claim 3, wherein the suction cup assembly comprises a sleeve slidably mounted on the shaft and directly carrying a vacuum head and suction cup and wherein a housing is mounted on said sleeve, and a link is provided pivotally connected at one end to the hub and at the opposite end to the housing and having a coupling pivotally mounted between the said ends and connected to the cam follower for transmitting motion of the cam follower to the link, whereby motion of the can causes motion of the suction cup assembly along the shaft.

5. A printer as claimed in claim 3 or claim 4 wherein said cam is so contoured so as to produce all the radial component of the motion of the suction cup assembly necessary to cause the cup to track the part of the path of the mandrel.

6. A printer as claimed in any preceding claim. further comprising a can infeed track for guiding cans under force of gravity from a supply to a rotatable pocket mandrel wheel having pockets on its circumferential surface. said track approaching the wheel in a nonradial path and forming an oblique angle with a tangent to the wheel at the intersection of the track and the wheel in the direction of wheel rotation, the track having an outlet portion that curves in the direction of wheel rotation and extends down to the depth of the pockets to redirect the path of the cans closer to the path of the pockets moving with the wheel; said pocket wheel having continuously adjacent pockets on its surface. each pocket having a leading and a trailing surface, the leading surface being smoothlv contoured to recede under the path of can entering the pocket from the track as the wheel rotates, without substantially interfering with the gravity induced motion of the can, said trailing surface contoured in an arcuate segment to seat the can and move it away from the infeed tract with the rotation of the wheel when the can is fully in the pocket.

7. A printer as claimed in claim 6 wherein said pocket mandrel wheel further comprises a mandrel axially aligned with each pocket for receiving the can from the pocket and supporting the can during contact with a rotatable printing blanket cylinder for decorating the can exterior; a vacuum source in each mandrel for drawing the can onto the mandrel; and a flexible spring element mounted adjacent the pocket wheel and contacting each can seated in the pocket to urge the can axially in the pocket, toward the adjacent mandrel, while said vacuum is applied through the mandrel to draw and seat the can on the mandrel.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **.

path by gravity, said infced means and pockets being free of moving parts. The wheel has a mandrel opposite each pocket. Spring means contact each can when it enters a pocket to start the can to move axially onto the mandrel while vacuum is applied through the mandrel, drawing and seating the can on the mandrel. The can is printed while held on the mandrel. After printing, the decorated can is blown off the mandrel onto a suction cup on a suction head which is part of a transfer assembly on a rotating transfer wheel. Movement of the suction head and cup radially downwardly on an angled shaft mounted on said rotating trans fcr wheel movcs the cup in a path coinciding with the path of the mandrel, and blowing air through the mandrel at the beginning of the coinciding path displaces the can from the mandrel to the suction cup where it is held by vacuum.

Movement of the suction cup and head further down on the anglcd shaft blocks vacuum passage, rclcases the can from the cup and plaices it on a pin of a chain convcyor. All motion of the housing 37 carrying the vacuum head and cup 43 is in a radial and axial direction, accomplished by a single cam action.

WI-lAT WE CLAIM IS: l. A continuous can printer incorporat- ing a transfer wheel for transferring decorated cans from the mandrels of a pocket mandrel wheel by discharge conveyor.

wherein the transfer wheel comprises: (a) a hub driven in time with the mandrel wheel about an axis substantially parallel to the axis of the mandrel wheel, (b) a shaft carried by the hub. the direction of the axis of the shaft having a radial component and an axial component relative to the axis of the hub, (c) a suction cup assembly slidably mounted for movement along the shaft.

(d) means for moving the suction cup assembly along the shaft, so as to track a part of the path of a mandrel on said man drcl wheel bearing a can, and (e) means for displacing the can from the mandrel to the suction cup, (f) means for applying a vacuum to the suction cup over a predetermined portion of transfer wheel rotation. so as to acccpt the can from the mandrel and to hold the can on the suction cup during the portion of transfer wheel rotation and for breaking the vacuum at the end of the portion of rotation to release the can to a discharge conveyor.
2. A printer as claimed in claim 1 wherein the discharge conveyor is a chain conveyor having pins for receiving cans from the transfer wheel.
3. A printer as claimed in claim ] or claim 2, wherein the means for moving the suction cup assembly on the shaft comprises a single cam cooperating with a cam follower connected to the suction cup assembly.
4. A printer as claimed in claim 3, wherein the suction cup assembly comprises a sleeve slidably mounted on the shaft and directly carrying a vacuum head and suction cup and wherein a housing is mounted on said sleeve, and a link is provided pivotally connected at one end to the hub and at the opposite end to the housing and having a coupling pivotally mounted between the said ends and connected to the cam follower for transmitting motion of the cam follower to the link, whereby motion of the can causes motion of the suction cup assembly along the shaft.
5. A printer as claimed in claim 3 or claim 4 wherein said cam is so contoured so as to produce all the radial component of the motion of the suction cup assembly necessary to cause the cup to track the part of the path of the mandrel.
6. A printer as claimed in any preceding claim. further comprising a can infeed track for guiding cans under force of gravity from a supply to a rotatable pocket mandrel wheel having pockets on its circumferential surface. said track approaching the wheel in a nonradial path and forming an oblique angle with a tangent to the wheel at the intersection of the track and the wheel in the direction of wheel rotation, the track having an outlet portion that curves in the direction of wheel rotation and extends down to the depth of the pockets to redirect the path of the cans closer to the path of the pockets moving with the wheel; said pocket wheel having continuously adjacent pockets on its surface. each pocket having a leading and a trailing surface, the leading surface being smoothlv contoured to recede under the path of á can entering the pocket from the track as the wheel rotates, without substantially interfering with the gravity induced motion of the can, said trailing surface contoured in an arcuate segment to seat the can and move it away from the infeed tract with the rotation of the wheel when the can is fully in the pocket.
7. A printer as claimed in claim 6 wherein said pocket mandrel wheel further comprises a mandrel axially aligned with each pocket for receiving the can from the pocket and supporting the can during contact with a rotatable printing blanket cylinder for decorating the can exterior; a vacuum source in each mandrel for drawing the can onto the mandrel; and a flexible spring element mounted adjacent the pocket wheel and contacting each can seated in the pocket to urge the can axially in the pocket, toward the adjacent mandrel, while said vacuum is applied through the mandrel to draw and seat the can on the mandrel.
8. A printer as claimed in any preceding

claim wherein the means for displacing the can from the mandrel to the suction cup comprises a controllable supply of compressed air connected to direct air through the mandrel, the mandrel having an air passage therethrough.
9. A continuous can printer as claimed in claim 1 substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.
10. A method of discharging cans in a continuous can printer which method comprises: transferring cans from a rotating pocket mandrel wheel to a discharge conveyor by moving a suction cup assembly, which is slidably mounted on a shaft carried by the hub of a transfer wheel, the hub having an axis substantially parallel to the axis of said pocket mandrel wheel, to track the path of a mandrel bearing a can, the direction of axis of the shaft having both an axial and a radial component relative to the axis of said hub, displacing the can from the mandrel to the suction cup at the beginning of the tracking of the mandrel by the suction cup, applying vacuum through the suction cup over a predetermined portion of transfer wheel rotation to hold the can on the cup, and breaking the vacuum holding the can, to release the can to a discharge conveyor.
11. A method as claimed in claim 10 wherein the printed cans are discharged to pins of a chain conveyor.
12. A method as claimed in claim 10 or claim 11 wherein each can is displaced from its mandrel to the suction cup by blowing air through the mandrel.
13. A method of printing cans which method comprises feeding cans successively in a guided path by gravity directly to pockets mounted on and stationary with respect to a rotating pocket mandrel wheel in positions axially opposite mandrels on the wheel, contacting each can successively with a flexible spring member after the can enters a pocket to guide the can to the opposite mandrel, applying a vacuum to the mandrel to draw and seat the can onto the mandrel, printing the can on the mandrel, and transferring the can from the mandrel by a method claimed in any one of claims 10 to 12.
14. A method of printing cans as claimed in claim 13 and substantially as hereinbefore described with reference to the accompanying drawings.

1 5. A method of discharging cans as claimed in claim 10 and substantially as hereinbefore described with reference to the accompanying drawings.