US3512478A - Conveying apparatus for printing equipment - Google Patents

Description

y 19, 1970 E. E. ROSE 3,512,478

CONVEYING APPARATUS FOR PRINTING EQUIPMENT Filed June 23, 1967 r 2 Sheets-Sheet 2.

INVENTOR. 56 62 E. E. ROSE A TTORNEVS United States Patent 3,512,478 CONVEYING APPARATUS FOR PRINTING EQUIPMENT Earl E. Rose, Fulton, N.Y., assiguor to Phillips Petroleum Company, a corporation of Delaware Filed June 23, 1967, Ser. No. 648,366 Int. Cl. B41f 17/28 US. Cl. 101-38 3 Claims ABSTRACT OF THE DISCLOSURE Conveying apparatus for the continuous feeding of containers to printing equipment which is capable of momentarily halting the translation of articles carried by a continuously traveling, endless chain While various printing operations are being performed on the articles.

This invention relates to apparatus for conveying objects. In one aspect, this invention relates to apparatus for the continuous feeding of containers to printing equipment. In another aspect, this invention relates to conveying apparatus which, although continuously moving, is capable of momentarily halting the translation of containers carried thereby for various operations.

Various types of techniques are employed for printing or decorating the exterior surface of containers. One technique commonly used is offset printing. In accordance with this technique, ink printing plate cylinders apply the printing or design material to a printing blanket, which is usually made of a rubber material, attached to the periphery of a rotatably driven printing drum. The printing or design material is transferred from the printing blanket to the exterior of the container by rotative engagement of the printing blanket with the container exterior. Through the use of multiple inking rollers and printing plate cylinders transferring printing or design material to the printing blanket, several different colors can be applied simultaneously to the container by a single printing blanket.

In order to preclude smearing of the printing or design, it is imperative that there be no relative linear motion between the container and the printing blanket while they are in rotative engagement, i.e. while the printing or design material is being transferred from the printing blanket to the exterior surface of the container. Present multicolor, oifset printing equipment utilizes a plurality of workholding units mounted on a turret head or endless, chain conveyer for moving the containers into position for printing. The turret head or conveyer is operated in a start-stop fashion. That is to say, the container is loaded onto a Work-holding unit, moved into position for printing, stopped momentarily for the printing operation, and then moved into position for unloading.

These start-stop, or intermittent-motion, feeding mechanisms have two major disadvantages. The first major disadvantage is that the production rate is necessarily limited because of the response time of the control and motive devices required to start and stop the turret head or conveyer. A production rate of approximately 60 to 100 containers per minute is about the maximum capacity in mechanisms of this type. Any production increase is dependent upon exact timing and synchronization of the start-stop cycle with the loading, printing and unloading operations, or refined, high-response, and therefore expensive, control and motive devices.

The second major disadvantage of this type mechanism is that the inertia and acceleration forces resulting from the start-stop cycle, especially when operating at higher production rates, transmit vibrations and pulsations into the equipment thereby making the maintenance of critical adjustments, such as container indexing, very difficult. Failure to maintain these various critical tolerances can 3,512,478 Patented May 19, 1970 result in degradation in the quality of printing; possibly even to the point that the printing is unacceptable for commercial usage.

Another technique commonly employed for printing or decorating the exterior surface of containers is screen printing. In accordance with this technique, the printing or decorating is applied to the surface of the container when an ink squeegee is pressed against a screen or stencil in contact with the container. Like the ofifset printing, there can be no relative motion between the screen and the containers during the printing operation; otherwise, smearing of the printing or decorative design will result. It has been proposed that this technique can be performed in a continuous manner by providing apparatus whereby the squeegee and screen are moved along the path of the container movement during printing and then reciprocated for printing of next container. Problems associated with and the complexity of the control and operating equipment necessary for performing and sequencing this reciprocating motion of the printing station are readily apparent. Vibrations induced by the reciprocating action can have detrimental effects as discussed above.

Apparatus for moving containers into position for printing which is capable of maintaining a constant linear speed but still momentarily halting the translation of the containers during the loading, printing and unloading operations is desirable for use with either of these printing techniques. Production rates can be increased substantially, vibrations induced by a start-stop cycle or reciprocation of the printing station can be minimized, and the complexity of the control and operating equipment can be reduced with such apparatus.

Accordingly, an object of this invention is to provide apparatus for feeding containers to printing equipment for printing or decorating which permits the elimination of a start-stop cycle.

Another object of this invention is to provide apparatus for feeding containers to printing equipment for printing or decorating which facilitates increased production rates and minimizes equipment vibrations.

A further object of this invention is to provide apparatus for the continuous feeding of containers to printing equipment for printing or decorating whereby the conveying means is moving at a constant linear speed and the translation of container-holding means mounted thereto is momentarily halted at various locations.

Further objects, aspects, and advantages of this invention will become apparent to those skilled in the art from the following detailed description, drawings, and appended claims.

According to this invention, a conveying apparatus operating at a constant linear speed is provided whereby a plurality of work-holding stations, attached to and depending from the continuously moving chain at spaced intervals, are momentarily halted at various locations for loading, printing, and unloading without halting the chain. This momentary halting is accomplished by guiding the chain through a circular arc, the radius of which is equal to the distance from the center of a container-holder on the work-holding station to the axis of the chain link to which the work-holding station is attached. As the link to which the Work-holding station is attached passes through the circular arc, the center of the containerholder corresponds to the center of the described circle and remains fixed in space. While in this fixed position at various stations, containers can be easily loaded onto the container-holder, a container can be printed While there is no relative linear motion between the printing device and the container, and the container can be easily removed from the holder. In addition to a containerholder, the work-holding stations include a roller which rides in a track. The track is configured so that the con- 3 tainer-holder and container are moved into and out of the printing position as the chain enters and leaves the circular arc. As the chain enters the circular arc, the container is urged into pressure contact with the printing drum or printing station as the roller rides along the track.

The continuously moving chain of this invention permits higher production rates because of the elimination of response times associated with start-stop systems. The apparatus of this invention also substantially eliminates the pulsations and vibrations induced by the start-stop motion of prior art systems.

FIG. 1 is a schematic representation of a side view of the conveyor system of this invention shown in conjunction with an offset printing drum.

FIG. 2 is a perspective view showing the attachment of work-holding station to the endless chain.

FIG. 3 is a detailed view, partially sectioned, of a Workholding station.

FIG. 4 is a detailed view, partially sectioned, of an exemplary container-holder for open-ended containers which can be used with this invention.

FIG. 5 is a detailed view, partially sectioned, of an exemplary container-holder for bottles which can be used with this invention.

The following detailed description with reference to the foregoing exemplary drawings will provide a better understanding of the invention.

Referring to FIG. 1, the apparatus shown comprises a conventional endless chain 2 engaged by sprockets 4, 6, 8, and 10. It will be understood that the structure illustrated has been depicted in simple form for each of understanding and clarity of illustration. The chain 2 is driven at a constant linear speed by one or more, or all, of the sprockets with the other sprockets, if any, acting as idlers. The path of chain 2 is determined by means of a pair of guides 12 and 14 together with sprockets 4, 6, 8, and 10. A plurality of uniformly-spaced work-holding stations 16 are carried by chain 2. Guides 12 and 14 are arranged so that chain 2 passes through a curvilinear path defining a circular are at printing station B, unloading station C, and loading station D. The apparatus guiding chain 2 and work-holding stations is similar for all three stations; hence, only the configuration and operation of the apparatus at printing station B will be discussed for purposes of clarity. The illustration of FIG. 1 shows only a diagrammatic representation of the path of the chain as related to the other stations.

As shown in FIGS. 2 and 3, work-holding station 16 includes a container-holder 18 rotatably attached to one end and a roller 20 rotatably mounted to the other end of support 22 which extends through the slides within cylinder 24. As described hereinafter roller 20 rides within and is guided by track 26. The portion of track 26 corresponding to the length of arc A, described hereinafter, is uniformly spaced from guide 14. This track 26 can extend around the entire perimeter of the chain if desired rather than being located at just the halting positions as shown in FIG. 1. As shown in FIG. 3, spring 28, disposed within cylinder 24 and in contact with retainer 30, urges roller 20 to engage with track 26. Support 22 is configured so that shaft 32 slides within sleeve 34. Spring 37 disposed within sleeve 34 urges containerholder 18 and container against the printing head as discussed hereinafter.

The work-holding station 16 is mounted to chain 2 by support bracket 36 (FIG. 2). Each of these support brackets is secured to a pair of adjacent pins 38, 40, on chain 2.

'FIG. 4 shows an exemplary container-holder suitable for holding open-ended containers, such as cottage cheese containers, for the printing operation. The containerholder includes a mandrel 42, having a shape generally conforming to the shape of the container 44 to be printed and a suction cup 46 which is mounted to mandrel 42 and connected through internal passage 48 and conduit 50 with a suitable vacuum source (not shown). Mandrel 42 is rotatably attached to adapter 52 so that it may rotate to permit the desired manipulation of the container relative to the printing head as described hereinafter. Adapter 52 is threaded to shaft 54 so that mandrels having various sizes and shapes can be easily installed onto each work-holding station, thereby providing the capability for using this invention with containers of many sizes and shapes.

The application of vacuum to suction cup 46 is controlled through conventional timing and valving apparatus. After a container is installed on mandrel 42, the vacuum is applied to maintain the container in place during the printing operation. Upon completion of the printing operation, the vacuum is released and pressure is applied through passage 48 to eject the container at the unloading station. It is to be understood that the timing of the application of vacuum and pressure to suction cup 46 is to be suitably controlled in relation to rotation of chain 2 passing through loading, printing and unloading stations. The control of the vacuum and pressure to suction cup 46 is not shown or described herein since a loading and unloading operation as far as this instant invention is concerned serves merely as a suitable means to facilitate installing and removing the containers upon and from the work-holding stations.

FIG. 5 shows an exemplary container-holder suitable for holding bottles onto the work-holding stations of this invention. Container-holder 56 includes a cup 58 rotatably mounted to adapter 60. The cup has a shoulder 62 in which the base of the bottle 64 to be printed is seated. A vacuum cup 66 is mounted in the bottom of cup 58 and connected through passage 64 and conduit 68 with a suitable vacuum source (not shown).

The open end of bottle 64 can be supported by any well known means which centers the container and provides internal support to prevent collapsing during the printing operation. Use of an expandable mandrel mechanism which is inserted through opening of the bottle and expanded therein is one proposed means for providing support for a bottle. Mechanism of this type is illustrated in U.S. Pat. 3,019,725 which issued on Feb. 6, 1962, and for the sake of completeness, the disclosure of that patent is incorporated herein. Another conventional means for supporting a bottle for the printing operation includes a pneumatic piston which pushes a centering and retaining pad into the mounth of the bottle and simultaneously injects air into the bottle. Air pressure provides the necessary internal support and aids suction cup 66 in holding bottle 64 securely during the printing operation. For purposes of illustration, FIG. 5 depicts this latter means. As the work-holding station enters the printing position with a bottle 64 held in cup 58 by suction cup 66, a centering core 70, made from a resilient material, such as soft rubber, carried by and operated by a pneumatic piston (not shown), is inserted into the mouth of the bottle 64. Air is simultaneously injected through passage 72 into bottle 64. Shaft 74 is rotatable so that the bottle rotates as described hereinafter when in contact with the printing device. Upon completion of the printing operation air is vented and the center core 70 is withdrawn from bottle 64, vacuum is released, and the bottle is ejected at unloading station C by air pressure supplied through passage 64.

Reference is made to the FIGS. 1 through 4 for the following description of operation of the conveyer system of this invention. The printing operation for an openended container will be described. A container is installed onto a container holder 18 by any conventional means, at loading station D. Vacuum is applied through passage 48 and suction cup 46 holds container securely onto container-holder 18. As chain 2 continues its constant linear motion in a counterclockwise direction it is guided through a circular arc A defined by guides 12 and-14 at printing station B. Three work-holding stations 16a, 16b, 16c, are shown in FIG. 1, 16a being at a position just prior to entering the printing station 16b being in the printing position and 16c being in a position just after leaving the printing station.

As the work-holding station moves into the printing station, roller 20 engages with track 26. As the distance between chain 2.and track 26 decreases, shaft 22 is extended so that the distance between the center of container-holder 16 and the center of pins 38 and 40 attaching work-holding station support 36 to chain 2, is equal to the radius R of circumferential arc A.

It will be readily appreciated that, when a work-holding station occupies the position shown by dotted line 76 in FIG. 1 and the middle of the corresponding attachment link of chain 2 has reached the start of circumferential arc A, the center of are A will coincide with the center of container-holder 18 and will continue to do so until the middle of the corresponding attachment link has reached the exit point of the circumferential are A as indicated by dotted line 78. The position defined by the center of are A is therefore one of momentarily halted translation of the container with respect to the continuously traveling chain 2 as it passes through arc A.

When the container-holder 18 is momentarily halted at the printing station as described above, the container to be printed is brought into juxtaposition with printing head 80 so that the desired printing may take place. FIG. 1 shows the conveyer system of this invention associated with a suitable printing machine in the form of an offset printing device. The details of the construction of this device are not shown since they form no part of the invention herein. It is to be understood that this printing device, which may be of a multicolor type, would include the usual printing plates, cylinders carrying the printing or design material to be applied to the containers and inking mechanism, all of which are not shown on the drawings.

The printing machine includes a rotatably-driven printing drum holding printing blankets 82 and 84. Printing head 80 is positioned so that container 44 is placed into pressure contact with printing blankets 82 and 84 when roller 20 following track 26 causes shaft 22 to compress spring 28 and extend. Spring 37 allows shaft 32 to telescope thereby preventing excessive load being imparted to the printing blankets 82 and 84 from dimensional tolerance changes resulting from wear, misadjustments, and the like.

As printing head 80 is rotated, container 44 mounted on rotatable container-holder 18 also relates because of being in pressure contact with the printing blankets. The printing or design material is transferred from the printing blankets 82 and 84 by rotative engagement of the printing head with the container exterior. The speed of printing head 80 is governed so that this printing operation is completed while a work-holding station passes through arc A, thereby insuring no relative linear or curvilinear motion between the container and the printing blanket. The rotation of printing head 80 is synchronized with the movement of work-holding stations so that a container is in proper engagement and alignment with the printing blankets when starting to pass through arc A. The spacing of the work-holding stations on the chain is dependent upon the linear velocity of the chain used and the rotational velocity of the printing drums so that this synchronization can be obtained. Of course, the minimum interval between work-holding stations must be greater than the circumferential dimension of are A so that the preceding work-holding station has moved out of the printing position before another moves in.

As a work-holding station exits from are A, roller 20 leaves track 26 and spring 28 returns shaft 22 to its original position, thereby retracting the container-holder 18 and container 44 from the printing head 80. At unloading station C, chain 2 is passed through an arc similar to that described previously in conjunction with the printing station B. Since there is no requirement for having a pressure engagement between the container and other apparatus at the unloading station, a track is not necessary although it can be used if desired. While the containerholder is momentarily halted at unloading station C, in the manner described above in conjunction with the printing station, the vacuum is released and pressure is supplied through passage 48 in container-holder 18 to eject the printed container. The printed container is transferred from the unloading station by conventional conveying means for further processing, packaging and the like.

The unloaded work-holding station then passes to loading station D where an unprinted container is installed, while the work-holding station is momentarily halted, a vacuum is applied through passage 48 in container-holder 18 to secure the container thereto and the cycle is repeated. As with the unloading station a track is not required at the loading station, but can be used if desired.

When a bottle is being printed, the operation is identical except centering core 70 (FIG. 5) is inserted by a pneumatic piston (not shown) and the container is pressurized as a work-holding station starts to enter are A, i.e. at the position shown by dotted line 76 in FIG. 1. As a workholding station exits are A, i.e. in the position shown by dotted line 78 in FIG. 1, pressure is vented and centering core 70 is withdrawn from the container. The initiation and sequencing of the operation of the piston and pressurization systems can be accomplished by any conventional electrical timing techniques or mechanical devices. These conventional techniques are not described in any detail because they do not comprise any part of the invention herein.

This invention can also be used in conjunction with screen printing equipment, in which case the containerholder is rotated by some conventional motive means with the printing screen remaining fixed, i.e. the containerholder is rotated during the printing operation. Otherwise the apparatus of this invention operates in the same manner when used in conjunction with either offset or screen printing equipment.

I claim:

1. Continuously traveling conveying apparatus for printing equipment capable of momentarily halting the linear motion of articles carried thereby at various positions, at least one of said positions being a printing station having a device for transferring printing or decorative material to articles, comprising, in combination:

(a) an endless chain having a plurality of links;

(b) pins interconnecting said links;

(0) a plurality of work-holding stations for carrying articles attached to and extending laterally from said chain at spaced intervals, each of said Work-holding stations being attached to at least one of said links and including an article-holding device rotatably mounted thereon;

(d) guide means, between which said chain travels, located at each halting position, said guide means defining a path for said chain comprising a circular are which is connected to the general path of said chain through entry and exit curves, the radius of said arc being equal to the distance between the center of one of said article-holding devices and the center of one of said pins of the corresponding work-holding station attachment link so that the center of said arc and the center of said article-holding device substantially coincide as the said corresponding attachment link passes between said guide means;

(e) transposition means for moving articles carried by said article-holding device into pressure contact with the printing device at the printing station while the corresponding attachment link is passing through said are associated with the printing station;

(f) each of said work-holding stations including a 8 slidable support means extending laterally on both References Cited sides of said chain; (g) said article-holding device rotatably attached to UNITED STATES PATENTS one end of said support means; and 1,116,406 11/ 1914 Fleischer 198-110 XR (h) roller means attached to the other end Of said sup- 5 2,143,118 1/ 1939 Todd 19819 port means. 2,198,565 4/1940 Schutz et al 10140 XR 2. The apparatus according to claim 1 wherein the 3,166,176 1 1965 Turner 101-40 XR transposition means comprises track means, on which S 3,204,756 9/ 1965 Lesch 19819 XR roller rides, spaced from said guide means, the p r 3,256,970 6/1966 Fieret 198-19 of said track means corresponding to the lengt of Said 10 3,356,019 12/1967 Zurick 101-39 are being uniformly spaced from said guide means so that said support means are extended towards the center of ROBERT PULFREY Primary Examiner said are as said roller rides along said portion of said track means. C. D. CROWDER, Assistant Examiner 3. The apparatus according to claim 1 wherein said 15 article-holding device is rotated by a motive means while US. Cl. X.R.

said corresponding attachment link is passing through said 198-19, 110

arc.

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