US3176609A

US3176609A - Automatic can marking device

Info

Publication number: US3176609A
Application number: US136844A
Authority: US
Inventors: Sr Charles Steckling
Original assignee: Jos Schlitz Brewing Co
Current assignee: Jos Schlitz Brewing Co
Priority date: 1961-09-08
Filing date: 1961-09-08
Publication date: 1965-04-06
Anticipated expiration: 1982-04-06

Description

April 6, 1965 c. sTEczKLlNG,v SR v 3,176,309:

K AUTOMATIC CAN MARKING DEVICE Filed sept. s. 1961 l 2 sheets-sheet 1 ,frV VL l JNVEIYTOR. Cha/ies tecllmgr. By/ndrus Star/(e @me s c. sTEKLlNG, sR 3,176,609v

AUTOMATIC CAN MARKING DEVICE N April 6, 1965 2 Sheets-Sheet 2 Filed Sept. 8. 1961 INVENTOA Charles Sec/(ln, sr: Y/ndrus Srle United States Patent O This invention relates to an automatic making device and particularly to a marking device for placing a multiple digit code number or the like upon the bottom cover of an upright can of beer or the like.

In the packaging of beer and the like in cans, an identifying code number related to the date, batch and the Y like is customarily placed directly on the can, preferably as the cans move along an automatic filling and packaging line. The cans are carried in an upright position on a flat belt-like conveyor forming a part of the line in immediately adjacent and touching relation. A coder wheel having a plurality of equicircumferentially spaced code printing elements is inserted in the line. A drive means is coupled to the coder wheel and driven by the cans to sequentially present a freshly inked coding element to each of the successive cans. A particularly satisfactory drive means includes a star wheel having a plurality of equicircumferentially spaced radial arms mounted to be engaged and moved by the cans. An ink pad is mounted adjacent the periphery of the wheel to continuously provide fresh ink on the coding elements. A selected code is thereby applied to each of the cans.

The top of the can is normally employed to carry certain identification and advertising matter and consequently the code number is preferably applied to the bottom of the can. However, if the dating wheel is mounted above the conveyor line, the top of the can must be disposed on the conveying mechanism during which time foreign matter and sediment may be picked up. Beer is often drunk directly from the can and consequently, it is important that the top of the can be kept clean. Such systems also require additional operations to turn the cans and present the bottom of the can to the printing unit and then to again return the can to the normal position for subsequent processing.

Presently known printing or dating units sequentially apply the individual digits of the code number or other symbol with the periphery of the wheel moving in the direction of the can line. Consequently, a relatively long period of time is required to elect the printing of the code number onto the can. As the cans are moving in immediately succeeding relationship during the printing operation, the following cans may bump into the can being printed and cause blurring of the code number and the like. This is particularly true in relatively high speed filling and packaging lines wherein the cans move along the line very rapidly.

When a printing wheel is employed7 it is necessary to continuously pass the wheel over an ink pad or the like to apply fresh ink before each printing. Where the numbers are applied in sequence and the wheel rotated correspondingly, the code numbers are applied to the pad at a relatively straight line and tend to compress and cut into the pad rather rapidly. This requires frequent replacement of the pads and the like.

The present invention is particularly directed to a high speed marking apparatus which is readily serviced and maintained and which is particularly adapted for applying code numbers to the bottom of a series of rapidly moving adjacent upright cans. The marking apparatus of the present invention includes means for rapid changing of the code on the printing wheel as well as the ink pad.

ice

In accordance with the present invention, the cans are carried through a conveyor station by laterally spaced chain means or the like. A coding wheel is mounted below the path of the cans and carries a plurality of circumferentially distributed printing inserts which are releasably secured to the periphery portion of the coding wheel. The individual digits or positions composing the code are .arranged laterally of the wheel and movement of the conveyor such that all of the elements therein are simultaneously and rapidly applied to the bottom of the cans. Can driven star wheels or the like are rotatably mounted to be driven by the can and serve to accurately align the cans for an instant over thev coding wheel. The adjacent prongs of the star wheels momentarily protect the cans during the code applying period from lthe following cans such 4that the can is relatively isolated against possible movement from the subsequent cans when the code is applied. The star wheels are also coupled to drive the coding wheel to sequentially present a dilerent printing insert to each of the` successive cans. An ink pad or other suitable ink source is mounted adjacent the dating wheel to continuously apply ink to the printing pads as the wheel rotates. Holding means may be provided overlying the cans for resiliently pressing the cans onto the conveying means within the marking station to allow the printing wheel to exert a rm upward printing pressure on the bottom of the can.

In accordance with an important feature of the present invention, the code wheel is mounted on a wheel shaft which is slidably attached to a pair of spaced hollow drive shafts. In operation, the star wheels are coupled to drive the hollow drive shafts. The wheel shaft is keyed or otherwise coupled to the drive shafts and to the code wheel to rotate the code wheel as the cans drive the star wheels. When the code on the code wheel is to be changed, it is merely necessary to remove the solid shaft and allow the code wheel to drop down between the hollow drive shafts. This provides a very convenient and rapid means `for changing of the printing inserts which arerreleasably held to the wheel.

The drawings furnished herewith illustrate the best mode presently contemplated for carrying out the invention.

ln the drawings:

FIG. 1 is a top plan view of a filling and packaging line `including a marking station constructed in accordance with the present invention;

FIG. 2 is a side elevational View of FIG. l;

FIG. 3 is an exploded view of the dating wheel and the mounting means therefor; and

FIG. 4 is a perspective view of FIGS. l and 2.

Referring to the drawings and particularly to FIGS. 1 land 2, a series of conventional beer cans 1 are shown passing through a marking station 2 with the beer cans in an upright position. The marking station 2 forms a part of a complete automatic filling and packaging line of which 'a conveyor chain 3 is fragmentarily shown in the drawings. The beer cans 1 are formed with the usual disked top cover 4 and bottom cover 5 and travel along with chain 3 with fthe top cover 4 facing upwardly. VThe bottom cover 5 rests on the flat continuous surface of chain 3 which is positively driven in any suitable means, not shown. The marking station 2 is mounted to one side of land extends parallel to the line 3. Vertical guide rails 6 join the filling and packaging line with the marking station 2 and divert the cans from the chain 3 into the markingstation 2. The marking station 2 includes marking wheel 7 rotatably mounted below the path of the cans 1 with a plurality of circumferentially spaced printing inserts 8 on the periphery of the wheel. Marking wheel 7 is driven in synchronism with the movement 3 of the cans 1 through the marking station 2 with successive cans momentarily engaged by successive printing inserts 8 to imprint the code number upon the bottom cover 5 ofthe cans 1.

The marking station 2 includes a track 9 upon which the cans are carried. A pair of endless block chains 1@ move longitudinally within the [station 2 to support and carry the cans 1 on the track 9. The guide'rails 6 prevent lateral movement of the cans. The trailing cans 1 on the main conveyor chain 3 force the preceding cans 1 into the marking station 2 'and on to the block chains which lthen pick up the cans and move them through the station 2. The block chains 10, as shown in FIG. l, are mounted to the opposite sidesV of the wheel 7 and allow the printing inserts 8 to move upwardly into engagement with the bottom cover 5.

A pair of vertically spaced can-driven star wheels 11 are mounted on one side of the path of the cans 1 within station 2 and a similar pair of vertically spaced star wheels 12 are similarly mounted in opposed relation to wheels 11 on the opposite side of the cans by respective shafts 13 and 14. Each of the star wheels 11 and 12 is identically constructed with equicircumferentially radial prongs or arms 15 projecting horizontally from the axis of the corresponding shafts 13 and 14. lArms 15 define a series of similar generally U-shaped openings which are vertically aligned in each pair of wheels 11 and 12. The opposed wheels 11 -and 12 are synchronously driven by the can 1 with the U-shaped openings being sequentially aligned to momentarily define a compartment within which a can 1 conveniently fits.

The star wheel shafts 13 and 14 are rotatably journaled in suitable support and bearing blocks 16 and 17 respectively and project downwardly below the plane of the chains 10. An identical bevel drive gear 18 is secured to the lower end of each of the shafts 13 and 14 andV is coupled to drive the marking wheel 7 in the following manner.

Referring particularly to FIG. 3, hollow drive shafts 19 and 20 'are rotatably mounted on opposite sidesjof the wheel 7 with their axis in alignment with each other and with the axis of the wheel 7 Each of the

shafts

19 and 20 is similarly supported by suitable bearing blocks 21 and 22 located at the opposite ends of the corresponding shafts. A bevel gear 23 is secured to the shaft 19 adjacent the bearing block 21 and mates with the bevel drive gear 1S of the star Wheel shaft 13. A similar bevel gear 24` is secured to the shaft 20 adjacent the block 22 and mates with the corresponding bevel drive gear 13 which is secured to the lower end of the star wheel drive shaft 14. The

hollow shafts

19 and 20 are thus driven by the star Wheels 11 and 12 and therefore in synchronism with the movement of the cans 1 through the marking station 2.

A marking wheel shaft 25 is slidably mounted extending through the hollow shaft 2i), a suitable aligned coupling opening in the wheel 7 and terminated within hollow shaft 19 to rotatably mount the wheel 7 between the shafts 19 land 20. i A key 26 extends for the length of the shaft 25 and mates with a corresponding keyway in the

hollow shaftsy

19 and 20` and the wheel 7, as shown in the drawing. The key 26 and keyway are related with respect to the bevel gears 18, 23 and 24 to locate each printing insert 8 in the vertical uppermost position whenY adjacent arms 15 of the opposed star wheels 11 and 12 are aligned over the marking wheel7 such that the U- shaped openings are in opposed alignment. The can 1 is then lheld within the arms 15 and relatively isolated from the following cans 1 when'the printing insert 8 is impressed onto the bottom of the can 1.

The cans 1 are moved through the marking station 2 by the chains 10 and drive the star wheels 11 and 12. The marking wheel 7 is driven by the stepped star wheels to sequentially present the printing inserts 8 to the bottom covers 5 of successively aligned cans 1.

The shaft 25 extends axially outwardly of the hollow shaft 20 and a control knob 27 is ixedly secured thereto. To prevent the axial movement of the marking wheel shaft 25 during operation of the apparatus, a radial opening 28 is formed in the wheel 7. A latching ball 29 is movably disposed within the radial opening V28 and biased downwardly into engagement with the yshaft 25 by a suitable coil sp1-ing 30 and ia set screw 31 threaded into the outer end of Vopening 2S. A groove 32 in the shaft 25 is engaged by the latching ball 29 and prevents free axial movement of the shaft 25. However, whenever it is desired to remove the wheel 7 for maintenance or changing of the printing inserts 8, it is merely necessary to exert a pull on the control knob 27 sufficient to overcome the tension force of spring 30 which releases shaft 25. The shaft'25 is pulled outwardly until the wheel 7 drops downwardly between the bearing blocks 22. The wheel 7 is replaced by aligning the openings in the wheel 7 and the openingsin the hollow shafts 19 and 2t) and pushing the shaft 25 into place with the key 26 mating with keyways in the respective members.

The illustrated marking wheel 7 is a relatively solid disc-like member having a regular polygonal periphery deiining a plurality of adjacent chordal portions. The printing inserts 8 are secured to alternate chordal portions and thus are equicircumferentially spaced about the wheel to continuously and successively present a different insert 8 to the cans 1 passing through the marking sta-V tion 2. The inserts 8 are releasably secured within suitable recesses in the chordal portions of the wheel 7, as follows.

A clamping plate 33 is iixedly secured to one axial face of wheel 7 and projects outwardly with the peripheral portion engaging the ends of the inserts 8. A clamping plate 34 is releasably secured to the opposite face of wheel 7 and projects outwardly with the peripheral portion engaging the opposite ends of inserts 8. Plate 34 includes circumferential slots 35 through which locking screws 36 project and thread into the marking wheel 7 forl angularly locating plate 34 with `respect to the wheel 7. Circumferential edge slots 37 are formed in the clamping plate 34 and are relatedto slots 35 for selectively aligning the edge slots 37 with the inserts 8 for inserting the latter in positionin wheel 7. With inserts 8 in place, the clamping plate 34 is rotated to move the edge slots 37 out of alignment with the position of the inserts 8 and the lock screws 36 are drawn up to tightly clamp the inserts 8 within the periphery of the marking wheel 7.

A tubular ink pad 38 is secured to the periphery of an ink pad drum 39 which is mounted adjacent the periphery of the wheel '7 immediately beneath the chains 10. The drum 39 is releasably secured to one end of a drum Yshaft 40 which is rotatably journaled within a bearing block 41.

In the` illustrated embodiment of the invention, the ink drum 39 is secured to the shaft 40 through a spring loaded ball catch comprising a latching ball 42 slidably journaled in a suitable opening in one end of the drum. A spring 43 is disposed within the opening and compressed by a small set screw 44 to continuously urge the ball 42 outwardly into engagement with the groove 45 in the drum shaft 4G.

Referring particularly to FIG. 4, a carriage 46 is secured to the top of the bearing-block 41 and slidably disposed within a guide track 47 for selective positioning Y of the drum 39 and pad 38 with respect to the periphery of wheel 7. An adjustment bolt 48 is journaled within a suitable bearing bracket 49 and threads into a suitable tapped opening 50 in the bearing block 41. Rotation of adjustment bolts 48 moves the drum 39 toward or away from the wheel 7, in accordance with the direction of rotation of the bolt, for adjusting the spacing of the ink pad 38.

A lock nut 51is threaded onto the bolt 4S and threaded against the block 41 for locking the bolt 48 and the attached bearing block 41 in position. To change the position of the bearing block, the lock nut 51 is threaded away from the block 41. The adjustment bolt 48 is rotated to properly position the drum 39 and the lock nut S1 is then returned into locking engagement bearing against the block 41.

A proper spacing of the ink pad 38 from the wheel 7 establishes optimum engagement between the pad 38 and the printing inserts 8 and prolonge the life of the pad. The proper adjustment also reduces the frequency of changing pad 3S.

To insure quality printing of the code on the cans 1, a pair of hold down shoes 52 are mounted overlying the path of the cans. The shoes 52 are resiliently mounted to engage the top of the can and hold the cans against the force of the printing inserts 8 in the following manner. A pair of U-shaped supports 53 are secured overlying the path of the cans 1. A cross-brace 54 is secured at its opposite ends to the upper portion of the Ushaped supports 53 in alignment with the path of the cans l. A vertical positioning plate 55 is secured beneath the crossbrace 54 by positioning bolt 55 having suitable adjusting nuts 57 threaded on opposite sides of plate 5S. Shoes S2 are secured to a resiliently mounted support block 58 having mounting shafts 59 projecting upwardly through suitable openings 60 in the plate 55. Hex nuts 61 thread onto the upper ends of the shaft 59 and support the block S8 on the plate 55. Coil springs 62 encircle the respective shafts 59 between the upper surface of the block 58 and the under side of the plate 55. The hex nuts 61 are threaded on the shafts 59 to locate the can engaging surface of shoes 52 generally immediately below the plane of the top covers 4 of the cans 1. The forward edges of the shoes 52 are curved as at 63 to allow the cans 1 to more readily move beneath the shoes 52. The cans 1 force the shoes upwardly and slightly compress the coil spring 62. The tension inthe coil springs 62 maintains a downward force holding the cans against the upward force of the printing inserts 8.

The operation of the illustrated embodiment of the invention is summarized as follows. The cans 1 are carried by the flat conveyor chain 3 of the filling and packaging line in an upright position and are diverted into the marking station 2 by the guide rails 6. In the marking station 2, the cans 1 are picked up by the block chains 1t? and4 carried between the star wheels 11 and 12. Each can 1 moves into rotating engagement with arms of star wheels 11 and 12 which project into the path of the cans and simultaneously rotate the marking wheel 7. At the moment the star wheel arms 15 to the front and back of a can are aligned, a printing insert 8 is applied to the bottom of the can. The insert 8 applies a suilicient upward pressure to print a clear code marking to the bottom cover 5 of the can 1. The shoes 52 prevent the cans from rising upwardly and insure a `lirm positive engagement between the bottom cover 5 and the insert 8.

The aligned arms 15 of the star wheels 11 and 12 momentarily isolate the can being printed from the following cans and eliminates the possible bumping and distorting of the marking.

The rotation of the marking wheel 7 by the can driven star wheels 11 and 12 rotates the printing inserts S into sequential engagement with the ink pad 38 which provides a fresh supply of printing ink for each application to a can. The drum 39 is freely rotatable due to the rotational engagement of the marking wheel 7 and presents a new area of the pad 38 to each succeeding printing insert 8.

To change the printing inserts 3, the wheel shaft 25 is pulled outwardly from the hollow drive shaft 19 and wheel 7 which drops downwardly below the -marking station. The locking screws 36 for the clamping plate 34 are loosened and the plate rotated to align the edge slots 37 with the printing inserts 3. The printing inserts 8 are slid out of the recesses and replaced. The clamping plate 34 is rotated to present the outer portion of the plate to the insert 8 and the lock screws 36 are tightened to securely clamp the inserts 8 to the wheel 7. The wheel 7 is then replaced with the keyways 27 in wheel 7 and the

hollow shafts

19 and 20 aligned to receive the shaft 25.

Similarly, if the ink pad 38 is to be changed, the drum 39 is pulled outwardly which will be readily released from the drum shaft de due to the spring loaded ball catch attachment of the drum to the shaft. After replacing the ink pad 38, the adjustment bolt 44 is rotated to properly locate the pad 318 with respect to the wheel '7.

The cans 1 are preferably printed after being filled. The additional weight of the filled can further increases the engagement with the printing insert S. lf desired, small magnets may also be employed to hold the cans down, for example, by inserting small magnets within the block chains 16. Y

The present invention provides a high speed, bottom marking apparatus for applying a clear imprint on the can and includes means for rapid and ready maintenance and replacement of parts.

Various modes of carrying out the invention are contemplated as being within the scope of the following claims particularly pointing-out and distinctly claiming the subject matter which is regarded as the invention.

I claim:

l. ln a marking apparatus for applying a mark to a series of containers;

(l) a marking wheel having a plurality of printing inserts equicircumferentially spaced about Vthe periphery of the marking wheel,

(2) a pair of hollow driven members rotatably mounted in spaced axial alignment to receive the marking wheel therebetween,

(3) a wheel shaft slidably disposed in the hollow driven members and rotatably supporting the marking wheel therebetween,

(4) coupling means rotatably securing the shaft to the hollow driven members and the marking wheel, said coupling means permitting axial sliding disengagement movement of the shaft with respect to the hollow driven members and the marking wheel,

(5) a resiliently loaded latch securing the marking wheel to the wheel shaft to hold the shaft against the sliding movement, and

(6) can driven means coupled to drive the hollow driven means in synchronism with the movement of the cans over the marking wheel.

2. A marking apparatus of the construction of claim 1 wherein the coupling means comprises;

(l) a key on said shaft generally coextensive with and mating with a keyway in the hollow driven members and the marking wheel to allow sliding of the shaft axially outwardly of the hollow driven members.

3. The marking apparatus of claim 1 wherein the can driven means comprises;

(l) a plurality of star wheels rotatably mounted in yopposed operative relation on opposite sides of the marking wheel and each star wheel includes radial arms overlying the path of the cans and engaged thereby for rotating the star wheels, the arms of the opposed star wheels defining can receiving compartments, and p (2) means coupling the star wheels to the hollow driven members to rotate the hollow driven members and the coupled marking wheel in synchronism with the movement of the cans, said means being selected to move a printing insert into operative imprinting position simultaneouslywith the alignment of the can receiving compartment over the marking wheel.

4. The marking apparatus of claim 3 wherein the plurality of printing inserts are releasably held in the 7 Wheel by clamping means secured to the wheel and engaging the opposite ends ofthe printing inserts.

5. The marking apparatus of claim l having;

(1) an inking drum rotatably mounted adjacent the periphery of the wheel, and

(2) an adjustable mount supporting the inldng drum for selective positioning of the drum relative to the periphery of the marking wheel.

6. A can marking -device for applying a multiple element code to the bottom of a series of tiled seated cans moving along a iillingline, comprising; Y Y Y (1) a marking Vline extending parallel tothe filling line and including a pair of laterally spaced blocktype chains for engaging the bottom covers of the cans and carrying the cans through the marking line,

(2) guide rails connecting the filling line to the marking line and diverting the cans into the marking line,

(3) a marking rwheel having a regular polygonal periphery and having an axial slot in the center of alternate sides thereof,

(4) printing inserts releasably secured within the axial slots,

(5) hollow driven shafts rotatably mounted in spaced axial alignment, r

(6) a wheel shaft projecting between said hollow driven shafts and supporting the marking ywheel therebetween, j

(7) means slidably coupling the wheel shaft toY be driven by the hollow driven shafts and to drive said marking wheel, Y

(8) resiliently loaded latch means releasably securing the marking wheel to the shaft to prevent axial movement of the shaft and to allow sliding of the shaft in response to a force sufficient to overcome the load of the latch means,l Y

(9) can-driven yopposed star wheels mounted in opposed relation on oppositel sides of the chains and having radial arms rotatable into the path of the cans and successively defining a can receiving come partnient overlying the path of the cans,

(10) means connecting the star wheels to the hollow driven shafts to rotate the marking wheel and present a fresh inked printing insert to veach can, said means being selected to impress the printing insert on the can when the can is held between the arms of the star wheell and isolated from the following cans,

(11) a resiliently mounted hold down shoe overlying the marking wheel in spaced relation to engage the top of the can with the printing insert in the printing position, Y

(l2) an ink drum rotatably mounted adjacent the marking wheel and having an ink pad on the outer surface,and

(13) means for adjusting the position of the bearing ink drum to control the engagement of the ink pad and the printing inserts. r

7. In a can marking device for applying a multiple element code to the bottom of a series of filled sealed cans moving along a conveying line,

(1) a marking line extending parallel to the conveying line and including a pair of laterally spaced blocktype chains for engaging the bottom covers of the cans and carrying the cans through the marking line,

(2) guide .rails connecting the conveyingk line to the marking line and diverting the cans into the marking line,

(3) a marking wheel having a regular polygonal periphery and having an axial slot in the center of alternate sides thereof,

(4) printing inserts disposed within the axial slots,

(5) a clamping plate xedly secured to one end face of the wheel, Y

(6) a clamping plate adjacent the opposite end face and having a series of circumferential attachment slots and a series of edge slots spaced in accordance with the spacing of said printing inserts,

(7 locking screws passing through the attachment slots and threaded into tapped openings in the marking Wheel to releasably secure the clamping piate to the wheel for clamping said inserts to the wheel,

(8) hollow drive shafts rotatably mounted in spaced axial alignment,

(9) a wheel shaft projecting between said hollow drive shafts and supporting the marking wheel therebetween,

(10) a key and keyway coupling the wheel shaft to the hollow drive shafts and said marking wheel, (l1) a spring loaded ball catch releasably securing the marking wheel to the shaft to prevent axial movement ofthe shaft, v

(12) can-driven opposed star wheels mounted in opposed relation on opposite sides of the chains and having radial arms rotatable into the path of the cans and successively defining a can receiving compartment overlying the path of the cans,

( 13) gear means coupling the star wheels to the hollow shafts to rotate the marking wheel and present a fresh inked printing insert to each can, said gear means being selected to impress the printing insert on the can when the can is held between the arms of the star Wheel and isolated from the following cans,

(14) a resiliently mounted hold down shoe overlying the marking wheel in spaced relation to engage the top of the can with the printing insert in the printing position,

(15) an ink drum having an ink pad on the outer surface, y

(16) an ink drum shaft rotatably supporting the drum,

(17) a movable bearing block carrying said ink drum shaft, and

(18) means for adjusting the position of the bearing block.

References Cited by the Examiner UNITED STATES PATENTS 875,092 12/07 Merrell 101-35 980,795 1/11 Kirkby lOl-35 1,535,539 4/25 Mitton 101-35 2,195,173 3/40 Jackson 101-35 Y 2,315,729 4/43 Nunnally 101-375 2,635,531 4/53 Bruce et al 101-35 2,761,380 9/56 Tiritilli 10l-40 2,790,386 4/57 Klaus 101-375 2,910,938 11/59 McKenzie 101-377 2,977,877 4/61 McVicker lOl-377 2,996,001 8/61 Schlegal et al 101-377 X 3,035,515 5/62 McKay 101-37 3,072,044 1/63 Jones 101-35 WLLIAM B. lENN, Primary Examiner.

ROBERT A. LEIGHEY, Examiner.

Claims

1. IN A MARKING APPARATUS FOR APPLYING A MARK TO A SERIES OF CONTAINERS; (1) A MARKING WHEEL HAVING A PLURALITY OF PRINTING INSERTS EQUICIRCUMFERENTIALLY SPACED ABOUT THE PERIPHERY OF THE MARKING WHEEL, (2) A PAIR OF HOLLOW DRIVEN MEMBERS ROTATABLY MOUNTED IN SPACED AXIAL ALIGNMENT TO RECEIVE THE MARKING WHEEL THEREBETWEEN, (3) A WHEEL SHAFT SLIDABLY DISPOSED IN THE HOLLOW DRIVEN MEMBERS AND ROTATABLY SUPPORTING THE MARKING WHEEL THEREBETWEEN, (4) COUPLING MEANS ROTATABLY SECURING THE SHAFT TO THE HOLLOW DRIVEN MEMBERS AND THE MARKING WHEEL, SAID COUPLING MEANS PERMITTING AXIAL SLIDING DISENGAGEMEMT MOVEMENT OF THE SHAFT WITH RESPECT TO THE HOLLOW DRIVEN MEMBERS AND THE MARKING WHEEL, (5) A RESILIENTLY LOADED LATCH SECURING THE MARKING WHEEL TO THE WHEEL SHAFT TO HOLD THE SHAFT AGAINST THE SLIDING MOVEMENT, AND (6) CAN DRIVEN MEANS COUPLED TO DRIVE THE HOLLOW DRIVEN MEANS IN SYNCHRONISM WITH THE MOVEMENT OF THE CANS OVER THE MARKING WHEEL.