US2761545A

US2761545A - Conveying means for a marking apparatus

Info

Publication number: US2761545A
Application number: US283189A
Authority: US
Inventors: Willard L Hoagland
Original assignee: Adolph Gottscho Inc
Current assignee: Adolph Gottscho Inc
Priority date: 1952-04-19
Filing date: 1952-04-19
Publication date: 1956-09-04
Anticipated expiration: 1973-09-04

Description

p 4, 1956 w. HOAGLAND 2,761,545

CONVEYING MEANS FOR A MARKING APPARATUS Filed April 19, 1952 5 Sheets-Sheet 1 PHIL INVENTOR 3 WILLARD L. Hone-mm:

Sept. 4, 1956 w. HOAGLAND CONVEYING MEANS FOR A MARKING APPARATUS Filed April 19, 1952 3 Sheets-Sheet 2 INVENTOR WILLHRD L. HMGLAND Se t. 4, 1956 w. HOAGLAND CONVEYING MEANS FOR A MARKING APPARATUS Filed April 19, 1952 3 Sheets-Sheet I5 INVENTOR WILLRRD L. Honcrmup United States Patent CONVEYING MEANS FOR A MARKING APPARATUS Willard L. Hoagland, Hillside, N. J., assignor to Adolph Gottseho, Inc, Hillside, N. 1., a corporation of New York Application April 19, 1952, Serial No. 283,189

6 Claims. ((31. 19s-s4 The present invention relates to apparatus for marking successive articles moving past a marking station, and is particularly directed to means for conveying the articles in spaced relation past the marking station.

In conveying articles, such as, for example, cartons, packages and the like, successively past a marking station of article marking apparatus, where an inked 1mpression is applied to the articles by a rotating die wheel or printing roll, it is necessary to move the articles in a predetermined spaced relationship and in synchronism with the surface speed of the die wheel so that perfect registration of the inked impression at a predetermined location on each article is assured.

It is an object of the present invention to provide a marking apparatus having automatic means for separating and spacing articles fed to the apparatus before they reach the marking station, regardless of the speed or frequency with which the articles are fed to the marking apparatus.

Another obiect is to provide marking apparatus of the character indicated having automatic means for interrupting the travel of one or more articles to be marked until a preceding article has been moved to a predetermined point along its path of travel toward the marking station so that the successive articles are separated.

Another 0 ,iect resides in the provision of a marking apparatus of the character indicated having automatic means for releasingan interrupted article in timed relation to the forwarding of a preceding article so that successive articles are spaced apart by a predetermined distance.

A further object is to provide a marking apparatus of the character indicated having means for synchronizing the feeding movement of the successive, spaced apart articles past a marking station with the surface speed of a rotating die wheel or printing roll at said station.

in accordance with the present invention the foregoing and other objects, features and advantages thereof are accomplished by providing a marking apparatus comprising a conveyor assembly for successively transporting the articles to be marked past a marking station at which one or more marking devices are located for applying an impression to desired surfaces of the successive articles. The conveyor assembly includes conveyor belts extending along an initial portion of the path of travel of the articles for receiving the articles fed to the marking apparatus, and conveyor chains extending from the conveyor belts past the marking station for receiving the articles from the belts and having spaced flights or pushers engageable with the received articles for conveying the latter past the marking station. Each of the marking devices is preferably of the kind including a rotating die wheel or printing roll arranged to effect rolling contact with a surface of each article as the latter is conveyed past the marking station and has an inking system associated with the die wheel for supplying ink to the surface of the latter so that inked impressions are applied to the successive articles. The motion of the conveyor chains l atented Sept. .4, 1956 in synchronized with the rotation of the die wheel so that the inked impression applied by the latter will be accurately registered with a predetermined surface area of each article being marked. The articles to be marked may be placed on the conveyor belts either manually or fed thereto automatically from a packing table, package sealing apparatus or the like, and such articles may be fed to the conveyor belts of the marking apparatus at any speed or frequency. In order to provide for the delivery of the successive articles from the conveyor belts to the conveyor chains in a manner so that the flights or pushers each engage only one article and convey that article past the marking station at a speed synchronized with the rotation of the die wheel or wheels, the marking apparatus according to the present invention includes means associated with the conveyor belts for separating the successive articles fed to the latter and for spacing the separated articles so that each article is deposited by the belts onto the conveyor chains in timed relation to the movement of the flights 0r pushers in the chains. The means for separating the articles fed to the conveyor belts includes a vertically reciprocating lifting assembly operative to raise an article out of contact with the conveyor belts for a predetermined period and then to lower the article onto the belts for continued travel after the preceding article has advanced a predetermined distance from the article acted upon by the lifting assembly. This separating means is coordinated and synchronized with the means for spacing the articles and timing their delivery to the conveyor chains so that each article, as well as any following articles fed to the belts, is interrupted in its travel while the immediately preceding article moves to the spacing means. The spacing means includes a retractable stop member movable into and out of the path of travel of successive articles conveyed from the separating means and synchronized with the operation of the latter so that the stop member is positioned in the path of travel of the articles when the lifting assembly has lowered an article onto the conveyor belts and is retracted from the path of travel of the articles when the lifting assembly has raised an article out of contact with the belts. A cam operated linkage system is provided for obtaining the desired coordination between the separating and spacing means and the cam operated linkage system is in turn driven from the conveyor chains so that the operations of the separating and spacing means are synchronized with the movements of the flights or pushers on the chains and of the die wheels or printing rolls of the marking devices.

A detailed description of an illustrative embodiment of the present invention is set forth hereinbelow and is to be read in connection with the accompanying drawings forming a part hereof and wherein:

Fig. 1 is a plan view of a marking apparatus embodying the present invention;

Fig. 2 is a plan view, partly broken away and in section, of a portion of the apparatus of Fig. l and shown on an enlarged scale;

Fig. 3 is a side elevational view of the portion of the apparatus appearing in Fig. 2;

Fig. 4 is a perspective view on an enlarged scale of interconnected elements included in the apparatus of Fig. 1; and

Fig. 5 is a diagrammatic perspective view of a portion of the driving mechanism for one of the marking units included in the illustrated marking apparatus.

Referring to the .dna-wings in detail, wherein like reference numerals are used to identify the same parts in the several views, a marking apparatus embodying the present invention is there generally indicated by the reference numeral 10. The marking apparatus 10 is construeted and arranged to apply inked impressions to the front, back and opposite side surfaces of successive articles, such as, cartons, packages and the like, and for this purpose includes a machine section 12, operative to apply inked impressions to the opposite side surfaces of the articles, and another machine section 14 disposed at right angles to the first mentioned section and operative to receive the successive articles from the latter and to app-1y inked impressions to the front and back surfaces of the articles. While the apparatus illustrated in the drawings operates to apply inked impressions to the front, back and opposite side surfaces of the successive articles, it is to be understood that embodiments of the present invention may be constructed to apply inked impressions to only the opposite sides of the successive articles, for example, by eliminating the machine section 14 of the illustrated apparatus, or to apply an inked impression to only one side surface of each of the successive articles.

The machine section 12 includes spaced apart and parallel frame members 16 and 18 supported on a suitable base 20 and having a shaft 22 rotatably extending therethrough at the ends of the frame members adjacent the machine section 14. A motor 24 (Fig. 2), which may be mounted on the base 20, is provided and drives a chain 26 passing around a sprocket 28 fixed on an end of shaft 22 for driving the latter.

Identical conveyor assemblies

30a and 30b are arranged along the confronting faces of the frame members 16 and 18 for transporting successive articles along the machine section 12 in the direction of the arrows A (Figs. 1 and 2) past a marking station B.

Each of the conveyor assemblies includes a conveyor belt section for carrying the successive articles along the initial portion of their path of travel, and a conveyor chain section operative to receive the articles from the conveyor belt section and to propel such articles past the marking station B for discharge onto the machine section 14.

The conveyor chain section of each of the assemblies 39a and 30b includes a sprocket 32 fixed on the shaft 22 and a sprocket 34 fixed on a stub shaft 36 which is journalled in suitable bearings carried by the adjacent frame member intermediate the length of the latter. The adjacent frame member (16 or 18 as the case may be) carries a guide 38 for supporting the upper run of a continuous chain 49 running around the

sprockets

32 and 34. Spaced flights or pushers 42 extend from the chain to engage behind successive articles delivered to the conveyor chain section and to propel such articles along inwardly directed, article supporting flanges 44 formed on the frame members 16 and 18. A ttensioning sprocket 46 is rotatably mounted on a rockable arm 48 and engages the lower run of each chain 40 to maintain the tension in the latter.

The conveyor belt section of each of the

conveyor assemblies

30a and 30b includes a roller or pulley 50 rotatably mounted on a shaft 52 extending from the related frame member adjacent the end of the latter remote from the machine section 14 (Fig. 2). A driving pulley 54 is fixed on a shaft 56 which is rotatably supported in suitable bearings carried by the related frame member at a location between shaft 22 and stub shaft 36 but close to the latter. A continuous belt 58 runs around the

pulleys

50 and 54 and the shafts supporting such pulleys are disposed so that the upper run of each belt 58 is substantially horiontal and only slightly above the upper surfaces of the article supporting flanges 44.

The movements of the belts 58 are synchronized with the movements of the chain conveyor sections and for this purpose shafts 36 and 56 are respectively provided with sprockets 6t) and 62 fixed thereon and around which a continuous chain 64 is trained so that the rotation of shaft 36 is a communicated to the shaft 56. Thus, articles fed to the end of machine section 12 remote 4 from machine section 14 will first be conveyed by the belts 58 and deposited by the latter onto the flanges 44, and then the flights or pushers 42 carried by the chains 40 will engage behind the successive deposited articles to convey the latter past the marking station B.

The articles fed to the machine section 12 may be placed upon the conveyor belts either manually or automatically from a packing table, package sealing apparatus or the like (not shown). In any event, the articles fed to machine section 12 must be separated and spaced apart while carried by the belt conveyor section so that, when the articles are successively deposited on the flanges 44, each article will be positioned for engagement by one of the flights or pushers 42, with the final movement of the article on the belts 58 being in timed relation to the movement of the pushers 42 so that only one article is deposited between adjacent pushers on the chains 40.

In accordance with the present invention, separating and spacing apart of the successive articles is achieved by a device which includes a vertically reciprocating lifting assembly operative to raise an article out of contact with the conveyor belts 58 for a predetermined period and then to lower the article onto the belts for continued travel after the preceding article has advanced a predetermined distance from the article acted upon by the lifting assembly. The lifting assembly is coordinated with a retractable stop assembly having a part movable into and out of the path of travel of successive articles conveyed by the belts from the lifting assembly so that the movable part projects into the path of travel of the articles, when the lifting assembly has lowered an article onto the conveyor belts, to limit the movement of the lowered article, and releases that article for further travel onto the flanges 44 when the lifting assembly has again been raised and one of the pushers 42 is approaching a position in which it will be eugageable with the released article as the latter reaches the flanges 44.

In the illustrated embodiment of the invention, the above mentioned lifting assembly (Figs. 2 and 4) includes a lift bar 66 disposed along the inside edge of each of the conveyor belts 58. Each lift bar 66 is pivotally connected at its opposite ends to

rock arms

68 and 70. Arm 68 is rockably mounted on shaft 52 which supports the pulley 50, and arm '70 is fixed on a shaft 72 which extends rockably through the adjacent frame member 16 or 18. The lift bar 66 is formed with upwardly opening bores 74 spaced along the length thereof to receive pins (not shown) extending downwardly from a lift block 76 for removably securing the latter to the bar 66 while permitting adjustment of the position of block 76 along the lift bar. The

arms

68 and 70 are dimensioned so that lift block 76 projects above the surface of the adjacent belt 58, when the rock arms are vertically disposed, and is Withdrawn below the conveyor belt, when the

arms

68 and 70 are inclined, as in Fig. 3.

Swinging of arms 68 and 79, to produce vertical movement of lift bar 66, is achieved by a cam operated linkage system which includes a crank arm 78 fixed on shaft 72 and connected to an adjustable link 80. The adjustable link 89 is in turn pivotally connected to an arm 82 which extends radially from a rock shaft 84 rotatably carried by the adjacent frame member. A cam follower arm 86 is fixed on the rock shaft 84 and at its end, which is preferably provided with a roller 88, rides upon the periphery of a radial cam 98. The cam 90 is fixed on a cam shaft 92 which is rotatably carried by the related frame member and has a sprocket 94 mounted thereon. A sprocket 96 is mounted on shaft 56 and a continuous chain 98 is trained around the

sprockets

94 and 96 to drive the cam shaft 92 in synchronism with the movements of the conveyor belt 58 and the conveyor chain 40. A tensioning sprocket 100 is carried by a pivoted arm (Fig. 3) and engages the chain 98 to maintain the latter in a taut condition. In order to maintain contact between cam 90 and follower arm 86, another arm 102 extends radially from rock shaft 84 and has a tension spring 104 connected thereto and anchored to a rod 106 extending from a spacer 108 carried at the inside of the related frame member.

When the radially enlarged portion of cam 90 engages the cam follower arm 86 the latter is rocked in the clockwise direction, as viewed in Figs. 3 and 4, to swing the

arms

68 and 70 to their upright positions for projecting the lift block 76 above the conveyor belt 58. Thus, any article disposed on the conveyor belts 58 above the lifting assembly will be raised clear of the conveyor belts and its movement will be interrupted. When the cam has rotated further, so that the follower rides off the radially enlarged portion, the spring 1134 will return the rock shaft 84 and the arms thereon counter-clockwise to the position shown in Figs. 3 and 4 for withdrawing the lift block 76 below the surface of the conveyor belt thereby lowering the article onto the conveyor belts to continue its movement.

In the illustrated embodiment of the invention, the retractable stop assembly, mentioned above, includes a stop member 110 mounted for vertical reciprocation adjacent the inside of each of the conveyor belts 58 at a location close to the sprocket 34 of the corresponding chain conveyor section. Each stop member 110 is preferably formed with longitudinal slots 112 receiving pins (not shown) extending from the spacer 1138 for slidably mounting the stop member on the spacer. In order to efiect vertical reciprocation of the stop member 110, the arm 102 has a pin 114 extending from its free end and engaging in a slot 116 formed in the lower end portion of the stop member. A spring 118 extends between the rod 186 and a pin 120 fixed to the stop member so that the latter is constantly urged upwardly for normally positioning the pin 114 at the lower end of slot 116.

As seen in Figs. 3 and 4, when the cam 90 is positioned for withdrawing the lift block 76 below the conveyor belts, the related stop member 110 projects above the level of the belt into the path of travel of an article carried by the conveyor belts. However, when the cam is positioned, as hereinabove described, for raising the lift block above the conveyor belt, the downward movement of arm 102 draws the stop member 116 downwardly so that the upper end of the latter is retracted out of the path of travel of articles on the conveyor belts. Thus, the described cam operated linkage system functions to alternately raise and lower the lift block 76 and stop member 110 adjacent the inside edges of the con' veyor belts.

The frame members 16 and 18 have guide rails 122 mounted thereon to guide the articles during their travel to and past the marking station, and the frame member 16 is preferably mounted on the base 20 in a manner to permit lateral adjustment thereof toward and away from the frame member 18 so that the distance between the guide rails 122 may be varied for accommodating articles of different dimensions. In the illustrated embodiment, the frame member 16 is mounted on supports 124 which are laterally slidable on the base, and worms 126 are rotatably carried by the base and threaded through the supports 124. A hand wheel 128 is provided on one of the worms 126 and the worms are preferably interconnected by a chain and sprocket arrangement so that turning of the hand wheel will simultaneously rotate the worms for effecting lateral adjustment of the frame member 16.

At the marking station B, one or more marking devices 136 are located. If only one side of each article is to be marked, then a marking device is mounted on only one of the frame members, as shown in Fig. 2, while a marking device is mounted on each of the frame members 16 and 18 when the opposite sides of each article are to have markings applied thereto, as shown in Fig. l.

Each marking device is of the kind which includes a rotated die wheel 132 positioned to make rolling contact with each article as the latter passes the marking station. In accordance with the present invention, the rotation of the die wheel 132 of each marking device is synchronized with the movement of the conveyor chains 40 so that the successive articles are moved past the marking station at a speed equal to the peripheral speed of the die wheel to prevent blurring of the impression applied to the article by the die wheel. Further, the location of the impression forming element or die on the die wheel is related to the locations of the flights or pushers 42 on the conveyor chains 40 in a manner so that the impression element comes into operative position for contact with an article as a pusher propels an article past the marking station thereby registering the applied impression with a predetermined surface area of the article.

In the illustrated embodiment of the invention, each marking device is generally of the type disclosed in the application of Letters Patent No. 110,920, now Patent No. 2,655,103, filed by Malcolm Hirschey, and includes, in addition to a die wheel or printing roll 132, an ink supplying roll 134 and an ink transferring roll 136 arranged for rolling contact with both the ink supplying and printing rolls. The

rolls

132, 134 and 136 are all mounted for rotation about vertical axes, and a nozzle 138 is disposed to direct a stream of ink against the surface of the ink supplying roll 134. A trough is arranged below the rolls to receive the excess ink dripping from the latter and to return the ink to a storage tank. A pump 149 is provided to propel the ink from the storage tank (not shown) to the nozzle 138.

In order to provide the desired synchronism between the rotation of the printing roll 132 of each marking device and the movements of the conveyor chains 40, a sprocket 142 (Fig. 2) is rotatable with shaft 22 for each marking unit. Each sprocket 142 drives a continuous chain 144 which also runs around a sprocket 146 rotatably carried on a stub shaft 148 journalled in a boss 150 formed on the related frame member. A bevel gear 152 (Figs. 2 and 5) is fixed on the shaft 148 and rotates with the sprockets 146. Bevel gear 152 meshes with a bevel gear 154 fixed on a shaft 156 carrying the ink transferring roll 136 and a spur gear 158 on shaft 156 meshes with a spur gear 160 fixed relative to the die wheel or printing roll 132 so that the ink transferring roll is driven positively by the chain and gear transmission from the shaft 22 and in turn positively drives the printing roll 132. The ink supplying roll 134 may be driven by the frictional force of its engagement with the ink transferring roll 136, or, if desired, may have a gear thereon (not shown) meshing with the gear 158 (Fig. 5).

The above described machine section operates as follows:

Articles to be marked are fed to the apparatus at the end of machine section 12 remote from machine section 14. The articles are conveyed by the belts 5:: and travel in the direction of the arrow A until the leading article abuts against the raised stop members 110. As the stop members 110 are lowered, to permit further travel of the leading article, the lift blocks 76 are raised to lift the article immediately behind the released article clear of the conveyor belts. The lift blocks 76 are positioned on the lift bars 66 so as to be positioned under the article immediately behind the article arrested by the stop bars 110. Thus, the leading article is conveyed by the belts 58 and deposited on the flanges 44, while the article next in line is held ofi the conveyor belts and has its travel interrupted. In this fashion, the successive articles are separated. The downward movement of the stop bars 110 is timed relative to the movement of the flights or pushers 42 on the chains 40 so that, as the released article is deposited from the belts 58 onto the flanges 44, a pusher on each of the chains moves around the sprocket 34 to the beginning of the upper run of the related chain to engage the back surface of the deposited articles. The pushers engaging the article then propel it along flanges 44 toward the marking station. As the article is moving past the stop bars 110, the bars are again moved upwardly by means of the spring 113; this time into. contact with the bottom of the moving article. The pressure of the spring 118 is so light that the article will not be raised thereby but will move along in sliding contact with the upper ends of the stop bars. As the trailing end of the article reaches the bevelled face on the upper end of each stop bar, the bars will slide off the trailing end of the article into their uppermost position. The pushers continue to propel the article past the marking station, and the movement of the pushers is coordinated with the rotation of the die wheels or printing rolls in the manner previously described so that the impression applied to one or both of the side surfaces of each article at the marking station is properly registered. After the impressions have been applied to the sides of the article, the latter is further propelled by the pushers and discharged from machine section 12.

In the apparatus of Fig. l, the successive articles discharged from machine section 12 are received by machine section 14. Machine section 14 includes frame members M2 and 164- arranged in parallel, spaced apart relationship and at right angles to the frame members of section 12. The

frame members

162 and 164 are mounted on a suitable base 166 and the frame member 162 is movable laterally toward and awayfrom member 154 to accornmodate differently dimensioned articles. The

frame members

162 and 164 include

horizontal flanges

168 and 170, respectively, on which the successive articles may slide. A support plate I72 is positioned between the flanges 168 and 179 to support the articles discharged from machine section 12 until such articles have moved onto flange 168 and 17%. In order to propel the articles deposited on the plate 172 along a path of travel passing a marking station C, machine section 14 includes

shafts

174 and 176 extending laterally thereof at the opposite ends and having

sprockets

178 and 184 respectively, mounted thereon. Chains 182 are trained around the sprockets 1'73 and E89 and have flights or pushers (not shown) extending therefrom to project above the surfaces or flanges 16S and 17% and propel the successive articles from the location where they are deposited by machine section 12 past the m rking station C of machine section 14.

in order to effect movement of the chains 182 in synchronism with the motion of chains 40 of machine section 12 so that the flights on chains 182 will come into operative position immediately after machine section 12 has deposited an article on plate 172, shaft 174 has a bevel gear 184 thereon meshing with a bevel gear 186 on shaft 22 thereby driving machine section 14 from machine section 12.

Machine section 14 includes marking units 130, similar to those previously described, which are mounted on frame members 162. and 1 54 at the marking station C. in order to synchronize the rotation of the die wheels or printing rolls of the marking units 13% at station C With the movements of the chains 1552, each of these marking units is driven by a sprocket 142 mounted on shaft 176 which drives a chain and gear transmission similar to that described in connection with the marking units of machine section 12. When the successive articles are conveyed along machine section 14 past marking station C, the previously marked opposite side surfaces of each article will be disposed fore and aft and the back and front surfaces of the article will be arranged for contact with the printing rolls of the marking units at station C.

From the foregoing description of the illustrated embodiment, it is apparent that the marking apparatus operates to apply inked impressions to four sides or surfaces of the successive articles, and that these impressions re properly registered in relation to the respective side surfaces without regard to the speed or frequency with which the articles are fed to the apparatus. Further, it is apparent that the present invention provides'mechanism for separating and spacing the articles fed to the apparatus and then conveying the spaced articles past marking stations in registered relationship with marking units located at such stations.

While a preferred embodiment of the present invention has been illustrated and described in detail, it is to be understood that the invention is not limited to that specific construction and that various modifications and changes may be made therein without departing from the scope of the invention which is intended to be defined in the appended claims.

What I claim is:

1. In mechanism for carrying successive articles to be marked past a marking station and including article advancing means having moving spaced article engaging members for propelling articles to be marked past the marking station, and conveyor means for receiving articles to be marked and operative to discharge the articles onto the article advancing means; the combination of retractable stop means movable into the path of travel of the articles on the conveyor means to time the discharge of the successive articles onto the article advancing means, and article separating means including at least one elongated bar extending longitudinally adjacent the conveyor means in advance of said stop means, means supporting said bar for movement substantially normal to the conveyor means between a lowered inoperative position and a raised operative position while maintaining said bar parallel to the plane of the conveyor means, and an article ting member mounted on said elongated bar and ad ustable along the latter to vary the distance between said lifting member and said stop means, said lifting member having suflicient height to extend above the plane of the conveyor means, when said bar is in said operative position thereby to lift the article disposed thercabove out of contact with the conveyor means, and to be retracted below said plane of the conveyor means when said bar is in its inoperative position thereby to return the lifted article onto the conveyor means, and actuating means operatively connected to said article separating means and retractable stop means to actuate the separating and stop means in synchronism with each other and with the movement of the article engaging membersv 2. In mechanism of the described character; the combination of conveyor means for transporting successive articles along a predetermined plane, article lifting means operative intermittently to lift successive articles out of contact with said conveyor means thereby to delay the travel of the lifted article for separating the latter from the preceding article on said conveyor means, a retractable stop member movable normal to said plane between an operative position projecting above said plane into the path of travel of the successive separated articles and an inoperative position withdrawn below said plane, and actuating means connected to said article lifting means and said stop member to actuate said lifting means and stop member in synchronism with each other so that said stop member times the discharge of the separated articles from the conveyor means, said actuating means including a rocked lever arm, pin and slot connecting means between said arm and said stop member to permit limited movement of the latter independent of said arm, and spring means yieldably urging said stop member toward its operative position so that rocking of said arm in the direction permitting movement of the said stop member to its operative position, at a time when an article is disposed above said stop member and resists such movement of the stop member, results in relative movement of said stop member and arm at said pin and slot connecting means.

3. In mechanism of the described character; the combination of conveyor means for transporting successive articles along a predetermined plane, article lifting means including two spaced apart and parallel, laterally extending shafts disposed equal distances below said plane, rock arms extending from said shafts, an elongated bar pivotally connected, at its opposite ends, to said rock arms and having a length equal to the distance between said shafts to be raised and lowered with respect to said plane in positions parallel to the latter, a lift member on said bar, means removably securing said lift member on said bar at a selected one of several positions along said bar, means for intermittently rocking one of said shafts so that said lift member is raised to a position above said plane to lift an article thereabove out of contact With said conveyor means thereby to separate the lifted article from the preceding article on said conveyor means and is then lowered to a position below said plane to return the lifted article onto said conveyor means, and retractable stop means movable into the path of travel of the successive separated articles on said conveyor means to time the discharge of the successive articles, and actuating means for said stop means synchronized with said shaft rocking means so that said stop means is retracted when said lift member is raised to a position above said plane and said stop means is moved into the path of the successive articles when said lift member is lowered.

4. In mechanism of the described character; the combination according to claim 3; wherein said means for intermittently rocking one of said shafts includes a rotated cam having a radially enlarged portion of relatively small angular extent, a rockable cam follower arm engaging said cam and resiliently urged against the latter, and transmission means between said one shaft and said cam follower arm arranged to rock said one shaft in the direction raising said lift member when said cam follower arm engages said radially enlarged portion of the cam; and wherein said actuating means for the cam means includes spring means urging said stop means to project into the path of the articles, and lost motion connecting means between said stop means and said cam follower arm operative to positively retract said stop means from the path of the articles when said cam follower arm engages said radially enlarged portion of the cam and to permit said spring means to urge said stop means into said path during engagement of the follower arm with the remainder of the cam, said lost motion connecting means permitting an article passing the stop means to resist movement of said stop means into the path of the articles.

5. In marking apparatus having a marking station; the combination of conveyor means for carrying articles to be marked along a predetermined plane past the markinoperative position thereof and releasing said stop means to permit movement of the latter to its operative position by said resilient means whereby, if an article on said conveyor means is disposed above said stop means at the time of the release of the latter, such articles can resist movement of said stop means to its operative position without damage to the article and said control means,

and means located adjacent said conveyor means at a location in advance of said stop means and operative to separate articles fed to the conveyor means and to delay the travel of the separated articles toward said stop means in synchronism with the operation of said control means.

6. In marking apparatus having a marking station; the combination as in claim 5, wherein said article separating means includes an elongated member extending parallel to said plane and moved substantially normal to the latter between raised and lowered positions, and an article lifting member adjustable along said elongated member to vary the distance between said lifting member and said retractable stop means, said lifting member being disposed below said plane, when said elongated member is in its lowered position, to permit movement of the articles thereabove by said conveyor means and being elevated above said plane, when said elongated member is in said raised position, thereby to lift an article thereabove off said conveyor means and separate the lifted article from the preceding article carried by said conveyor means.

References Cited in the file of this patent UNITED STATES PATENTS 1,020,746 Dehler May 19, 1912 1,461,638 Wells et a1. July 10, 1923 1,616,101 Ackley Feb. 1, 1927 1,718,443 Straight June 25, 1929 1,770,029 Eberhart July 8, 1930 1,845,726 Scott Feb. 16, 1932 2,109,590 Kimball Mar. 1, 1938 2,664,816 Gibson Ian. 5, 1954