05/414456

11/19/1974

11/09/1973

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Procter Paint and Varnish Co., Inc. (Yonkers, NY)

53/489

100/49, 53/314, 100/221, 100/51, 53/320, 53/319

B65B7/28; B67B1/04; B65B7/28

53/313,314,315,316,320,326,328,333,282,324,319,75,76,38,43,37 100/49,51,221

3715865

CAPPING DEVICE FOR CONTAINERS

February 1973

Davis

Mcgehee, Travis S.

Culver, Horace M.

Kenyon & Kenyon Reilly Carr & Chapin

What is claimed is

1. A lid-applying machine for closing filled containers comprising a feed line on which said containers are movable, a lid-depositing means positioned at a station along said feed line, means for advancing filled containers in abutting relationship along said feed line to and away from said lid-depositing means at said station, said lid-depositing means including means for maintaining a stack of lids, hold-back presser means movable reciprocally toward and away from said stack of lids and removably engageable with lids in said stack, and actuating means located along said feed line operated by said containers to actuate said presser means to effect momentary release and reengagement of said stack for deposit of a single lid onto a lidded container at said station, means for retaining said single lid against movement with said lidded container whereby movement of said lidded container along said feed line causes said released single lid to be applied to the next adjacent filled container.

2. A lid-applying machine according to claim 1, wherein said means for maintaining a stack of lids at said station comprises guide rods disposed at spaced-apart points about a periphery slightly greater than the lid periphery between which lids in said stack are guided for downward movement as permitted by release movement of said hold-back presser means.

3. A lid-applying machine according to claim 2 wherein one of said guide rods is located directly opposite said hold-back presser means and against which periphery portions of lids are pressed by said presser means on its engagement with said lids.

4. A lid-applying machine according to claim 3 including means on said one of said rods engageable with periphery portions of lids to enhance hold back of such lids during engagement of said presser means therewith.

5. A lid-applying machine according to claim 2 wherein some of said guide rods are located respectively at a lagging position and at a leading position relative to direction of container movement along said feed line, the lowermost ends of the lagging guide rods being disposed to lie adjacent the upper ends of containers being advanced along said feed line with a clearance however sufficient to permit free movement of containers along said feed line to said station, and the lowermost ends of the leading guide rods being disposed at a level that will prevent movement of the released single lid away from under said stack during advance motion of the containers until said released lid has completely entered the opening of the container then underlying said stack.

6. A lid-applying machine according to claim 1 wherein said presser means comprises a pressure-actuated cylinder, and a pressure circuit for actuating said cylinder to effect reciprocal movement of said presser means, and control means for said circuit operated by said containers during their movement along said feed line.

7. A lid-applying machine according to claim 1 including a lid press-down station along said feed line following said first-named station, press-down means at said lid press-down station, and means activated by successive containers bearing lids arriving at said press-down station to press each such deposited lid down onto its underlying container and seat and seal such lid on such container.

8. A lid-applying machine according to claim 7 wherein said press-down means comprises a reciprocally movable pressure activated pressing member, and means for effecting reciprocal movement of said pressing member, said last-named means being actuated by movement of said containers along said feed line.

9. A lid-applying machine according to claim 7 including a pressure circuit comprising a pair of branch conduits connected to a pressure source, valve means operated by containers arriving at said press-down means to activate one of said branch conduits to effect press-down movement of said press-down means, valve means operated by press-down movement of said press-down means to activate a second of said branch conduits to effect a retractive movement of said press-down means, and time delay means in each of said branch conduits for providing time lags respectively in press-down movement and retractive movement of said press-down means subsequent to operation of each of said valve means.

10. A lid-applying machine for closing filled containers comprising lid-depositing means, a feed line along which said containers are movable, advancing means for moving said containers step-by-step along said feed line to a station at which said lid-depositing means is located, said lid-depositing means including means for maintaining a stack of lids at said station wherefrom a lid from the stack is deposited on each container arriving at said station, and hold-back means for engaging lids in the stack and releasing only the lowermost lid in the stack for deposit on a container previously lidded at said station, said hold-back means comprising a reciprocally movable presser means engageable removably with lids in the stack during movement of said containers along said feed line, means for retaining said lowermost lid against movement with said lidded container whereby movement of said lidded container along said feed line causes said released single lid to be applied to a next adjacent filled container, and means along said feed line for actuating said presser means during movement of said container.

11. A method of applying lids to filled containers comprising maintaining a stack of superposed lids along a feed line for said stack, releasing a single lid at a time from said stack for deposit onto a previously lidded container under said stack, retaining said single lid against movement with said previously lidded container, subsequently moving said previously lidded container whereby movement of said previously lidded container along said feed line causes said released single lid to be applied to a next adjacent filled container, and pressing a lid previously applied to said previously lidded container onto said container to close and seal the latter.

12. A method of depositing lids to open ends of filled containers comprising maintaining a stack of superposed lids along a feed line, moving said containers to, under and away from said stack, during movement of each such container under said stack and in advance of its arrival there releasing a single lid from said stack to rest partially on a lidded container that has been moved partially away from under the stack and partially on the arriving open container, holding back lids in the stack above said released single lid, retaining said released lid under said stack despite movement of the lidded container until the open end of an arriving container lies fully under said released lid and said released lid deposits itself into said open end of the fully-arrived container, and subsequently moving the container bearing the deposited lid away from under said stack, and controlling lid-by-lid release and holding back of lids in the stack by movement of said containers along said feed line.

13. A method according to claim 12 including the subsequent step of pressing down into sealing seated relationship the deposited lid on each container bearing such lid.

14. A method according to claim 13 wherein said pressing down is effected in at least two stages, the first stage effecting a partial pressing down of the deposited lid and the second stage completing said pressing down to prevent entrapment of air in the container.

15. A lid-applying machine for closing filled containers comprising a feed path along which containers are moved, a lid-depositing means positioned at a station along said feed path, said lid-depositing means including means for maintaining a stack of lids, hold-back presser means movable reciprocally toward and away from said stack of lids and removably engageable with lids in said stack, means for positioning two containers partially beneath said stack of lids such that each container is extended approximately one half a diameter outside of said stack, the leading one of the said two containers having a lid deposited thereon and the other being unlidded, and actuating means located along said feed path and operated by said containers to actuate said presser means to release said stack by moving reciprocally away from said stack whereby the said two containers support said stack of lids, means for moving said two containers a distance equal to approximately one container diameter whereby a released lid is deposited on the unlidded of said two containers, and means actuated by said containers to actuate said presser means to move reciprocally toward said stack to engage a plurality of lids in said stack above the lowermost lid, whereby the lowermost lid is supported by the two containers sharing the space beneath the said stack.

16. A lid-applying machine according to claim 15 including press-down means for sealingly seating the deposited lid on its container, said press-down means including a pressing member dimensioned so that said member will fully overlie a container centered thereunder and partially overlie directly adjacent lagging and leading containers, and means actuated by movement of said containers to operate said pressdown means and partially engage and seat the deposited lid on the lagging container at a bias and complete the seating of the lid on the central container, thereby avoiding entrapment of air within the fully lidded containers.

17. The method of applying lids to filled containers comprising the steps of arranging said containers in a sequence in which the containers are abutting, arranging a vertical stack of lids in nested order at a station; transporting said containers up, to and beyond said station so that at a point of time there is a lidded container and an unlidded container partially beneath said stack of lids, said lidded container protruding approximately one half a diameter beyond the stack of lids and said unlidded container protruding approximately one half diameter in a direction preceding said stack; providing reciprocally operable means to engage all of said stack of lids except the lowermost one so that said stack is restrained from moving in a downward direction; transporting said lidded and said unlidded containers so that said lidded container moves entirely out from beneath said stack of lids and said unlidded container moves directly beneath said stack of lids thereby accepting the lowermost free lid and thereby becoming lidded; continuing to move said last named lidded container so that it begins to protrude beyond said stack and actuating said reciprocally operable engaging means to release said stack thereby freeing the lowermost lid which falls to rest upon said named lidded container, continuing to move said last named lidded container while at the same time leaving an open container in abutting relationship therewith; said last named opened container and said last named lidded container being transported until it is one half beneath said stack of lids and protruding one half outside said stack of lids; and continuing to repeat the above process thereby applying lids to a sequence of open containers.

RELATED APPLICATIONS

No related applications are co-pending.

FIELD OF THE INVENTION

In prior art lid-applying devices, a set of mechanical fingers was used to drop lids, one by one into an inclined chute. The lower opening of the chute was positioned above an open can and it was intended to have the single lid fall through the chute and drop into place on the can. The release of the lids occurred by the use of a tripping device on the conveyor which was carrying the cans to be lidded.

These types of devices suffered for several defects. First, the fingers were, of necessity, sensitive to the diameter of the lid and thus, from time to time, more than one lid would be dropped into the chute at the same time because of slight differences in diameter. In addition, the lids sometimes would become caught in the chute. These types of problems require shutting down the entire line in order to correct the situation.

BRIEF SUMMARY OF INVENTION

The present invention relates to a lid-applying machine for covering and sealing containers filled with liquids and is of especial utility where inflammable liquids constitute the fill of the containers. The deposition of a lid on a filled container from a vertical stack of lids maintained at a lid depositing station is controlled by pneumatically activated means responsive to pneumatic controls operated automatically by container positions toward the lid depositing station, and away from said station to a lid press-down station at which a pneumatically operated press activated by a pneumatic switch serves to press the lid down firmly and sealingly on and in seated condition on the container.

It is known in the art to provide machines for applying lids to filled containers but the known machines are very complex and very expensive. They usually are of a type wherein the lids are singly fed via a chute to a lid-applying and pressdown location for application to filled containers. Failure of a lid to appear for application to containers fed to the lid-applying and press-down location as well as appearance of more than one lid are drawbacks to the use of such devices.

Primary objects and features of the present invention are the provision of novel, much less expensive machinery for positioning lids in succession onto containers arriving at a lid-depositing station and subsequent delivery in succession of lid-bearing containers to a lid press-down station whereat the deposited lid on each successive container is pressed down firmly into sealed seated relationship over the container opening.

Other objects and features of the invention are the provision of pneumatic operating means and a pneumatic control system activated by container positions in transit from a filling machine, to at and away from the lid-depositing and lid press-down stations which render the machine entirely safe to use with inflammable liquids.

Further objects and features of the invention are provision of a machine of this type wherein electrical control device systems are avoided because of explosion hazards that sparking of electrical equipment might create.

The lid-depositing and press-down mechanisms of the present invention are applicable for use in conjunction with conventional container filling machinery, and although not limited thereto, are in particular adjusted for use with the filling apparatus described in my U.S. Pat. Nos. 3,536,925 of Oct. 27, 1970 and 3,702,625 of Nov. 14, 1972 whose structures are incorporated by reference herein.

Other objects and features of the invention will become apparent from the following detailed description and the accompanying drawings forming part thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of an automatic lid-depositing and lid-seating apparatus in relationship to an automated container filling system;

FIG. 2 is an elevational view of the structure of FIG. 1;

FIGS. 3, 4 and 5 are successive positional views of containers in relationship to the lid-depositing mechanism illustrating the manner of effecting sequential deposition of lids into successive containers from a stack thereof maintained at the lid-depositing station;

FIG. 6 is a view taken along the plane of line 6--6 of FIG. 3 viewed in the direction of the arrows and illustrating pneumatic hold-back means for lids in the stack at said lid-depositing station;

FIG. 7 is an elevational view showing the press-down mechanism at the lid-seating station at which in sequence containers bearing lids deposited at the lid-depositing station are pressed down into seating and sealing position on such containers;

FIG. 8 is a diagrammatic illustration of the pneumatic control system for activating the sequential advance of containers by a pneumatic or hydraulic pusher upon completion of container fill toward the subsequent lid-depositing and lid press-down stations;

FIG. 9 is a schematic diagram of the pneumatic or hydraulic control circuit that serves to operate a pneumatic or hydraulic lid hold-back mechanism that is controlled by container movement to effect sequential liberation of lids from the stack for deposition on sequential filled containers arriving at the lid-depositing station; and

FIG. 10 is a schematic diagram of the pneumatic or hydraulic control circuit that serves to operate the lid press-down and seating mechanism located at the press-down station.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

Referring to FIGS. 1 and 2, empty containers or receptacles 10, for example, metal cans to be filled with a flowable material such as paint are placed on a turn-table 11 of a can feeding device 12, similar, for example, to that in my aforesaid U.S. Pat. No. 3,702,625 which serves to feed a single line of containers 10 into chute 14 which discharges into feed line 15. Since the containers 10 are free to slide on the surface of turn-table 11, the chute 14 is kept full, but stationary until there is a demand for cans or containers 10 on the feed line 15.

The feed line 15 extends longitudinally from the discharge location of chute 14, and can or container filling apparatus denoted generally by reference character 16, lid depositing apparatus denoted generally by reference character 17, and lid press-down apparatus denoted generally by reference character 18, are respectively located in succession at respective stations I, II and III along the feed line 15.

Cans or containers 10 on feed line 15 are advanced one step (i. e. the distance of one can or container diameter) at a time by a pusher 19 which is actuated by pneumatic or hydraulic cylinder 20. It will be understood that different sizes of cans or containers can easily be accommodated by adjusting the spacing of side rails 21 of chute 14, side rails 22 of feed line 15, and pusher 19. It will also be understood that the delivery of the cans or containers 10 to the feed line 15 for step-by-step advance along the latter by pusher 19 can be effected in any other convenient manner.

The filling apparatus or means 16 shown only diagrammatically herein located at station I is, for example, that described and illustrated in my aforesaid U.S. Pat. No. 3,702,625 which serves to fill each can or container 10 successively to desired level with the desired flowable material such as paint. As described in said patent, filling of cans or containers is effected in two stages, namely, a valve-controlled partial prefill in the first stage and a completion of fill in a second valve-controlled stage. The respective fill spouts 23a and 23b for these two stages are spaced apart the distance equal to the diameter of one can (or of multiples of one diameter if more convenient) and positioned so that the next empty can 10c is positioned under spout 23a at the completion of forward stroke of pusher 19 actuated as will be described. Simultaneously, the partially filled can 10a is advanced to underlie spout 23b while the completely filled can 10b under spout 23b is advanced the diameter of a can or container 10 along feed line 15 toward the lid-depositing station II. Completion of fill of the can or container 10b underlying spout 23 at station I is detected by material level sensing means 24 (e. g. sensing head 40 of my aforesaid patent) and associated mechanism including a photocell and requisite components. Control valve 25 is responsive to sensing means 24 and controls the forward and retracting strokes of the pusher 19. This control valve 25 (FIG. 8) is a conventional pneumatic or hydraulic device for alternately supplying pressure fluid to cylinder 20 from a pressure fluid source 26 at the requisite side of its piston 20a via respective conduits 27 and 28. It is, of course, understood that any other type of liquid level sensing means may be utilized in lieu of the arrangement described in said U.S. Pat. No. 3,702,625. Its main feature is that it should activate the cylinder 20 to effect a forward pushing stroke of pusher 19 each time a can or container 10 has been filled to requisite level at station I.

The single step feed of cans along feed line 15 by pusher 19 moves the filled cans beyond filling station I, to the lid-depositing station II. The lid-depositing apparatus 17 at the station II will now be described.

LID-DEPOSITING APPARATUS

The lid-depositing apparatus at station II is located along the feed line at a distance (nd - 1/2d) from the filling station I, d being can diameter and n any selected integer.

The lid-depositing apparatus 17 comprises a group of vertically supported rods 29, 30, 31, 32 disposed at equi-arcuate locations of a circle L', whose diameter is substantially equal to or slightly greater than that of the lids L to be deposited. An additional vertical rod 33 is positioned approximately equidistance between rods 29 and 32 on the periphery of circle L'. The spaced rods 29-33 serve as a vertical slide guide and vertical support for a stack S of lids L which are intended to be deposited one by one on successive containers at said station II. The rods 29 and 30 are of like length and their lower ends are positioned to lie adjacent the open mouths of unlidded containers 10 which are advanced along the feed line 15 by pusher 19. Rod 33 may be of length equal to rods 29 and 30.

As will be described in detail below, rods 31 and 32 assist in preventing the free or bottom lid L from moving forward before being seated on an open can. Accordingly, the lower ends of rods 31 and 32 must be low enough to prevent a lid resting on an already lidded container from moving forward when the lidded container moves. At the same time, however, the lower ends of rods 31 and 32 must be high enough to permit a lidded can to move thereunder freely. Thus, the ends of rods 31 and 32 terminate in a horizontal plane located above the lower ends of rods 29 and 30 at a distance somewhat greater than the height of a lid L.

Restraining means 34 is provided which serves to restrict downward movement of lids L in the stack S in such a way that only the lowermost lid L in the stack S is free to fall downward for deposit onto the open end of a filler container arriving at station II. This restraining means 34 in the embodiment shown (FIG. 6) comprises an hydraulic or pneumatically supplied cylinder 35 carrying a piston operated gripper head 36 which is supported suitably to extend transversely of feed line 15. The outer end of head 36 is provided with a resilient gripper shoe or cushion 37 of rubber or other material that may have concave curvature corresponding to that of the convex peripheries of lids L. The cushion 37 has a vertical dimension equal to the combined height of at least three lids in the stack S and its lower edge is positioned at the level of the lid directly above the bottom lid L in said stack. When the cylinder 35 is activated to effect an inward movement of gripper head 36, the cushion 37 presses firmly against the second, third and fourth lids from the bottom lid L, biasing them against the diametrically opposite rod 33 so that all of the lids L except the bottom lid are held fast against downward guided movement of gripper head 36. Appropriate energization of cylinder 35 frees the gripped lids L, then all of the lids L in stack S are free to move downwardly until cylinder 35 is reversely activated to restore engagement between shoe 37 and the three lids now occupying the space occupied by the three previously gripped lids. Optionally, rod 33 at its lower end may be provided with an inward radially directed nose or protuberance 33a (FIG. 6) adapted to engage under the usual peripheral lip of the lid directly above the bottom lid in the stack S when the gripper head 36 is in extended lid-grippping position, thus reinforcing the lid-holding action of the shoe 37.

As a further option, to assist the lid-holding action of shoe 37 when extended, notches (not shown) can be provided in the rods 29 and 32 into which lid lips are forced by pressure of shoe 37.

It is essential that air or hydraulic feed to the cylinder 35 be controlled to provide proper sequential timing of gripping and release movements of gripper head 36 and its shoe 37 relative to the lids L in stack S. To this end, as seen in FIG. 9, pressure fluid hydraulic or air from a source is delivered to conduit 38. The latter in turn is connected to a "T"-head 39, one of whose outputs is connected via a conduit 40 to a normally closed pneumatic bleed type pilot valve or switch 41 and from the latter via conduit 42 to the retracting stroke side of cylinder 35. The second output of T-head 39 is connected by conduit 43 to a second normally closed pneumatic bleed type pilot valve or switch 44 and from the latter via conduit 45 to a T-head 46 and from the latter via conduit 47 to an air impulse relay 48 and from the latter via conduit 49 to the forward (inward) stroke side of cylinder 35. In addition, pressure fluid is deliverable to normally closed pneumatic switch 50 operable by push button 51 to open position. Conduit 52 connects switch 50 to the T-head 46.

The pilot switch 41 is positioned between the filling station I and the lid-depositing station II along the feed line 15 and the pilot switch 44 is positioned beyond station II and in advance of lid press-down station III. These pilot switches 41 and 44 have respective operating arms 41a and 44a which project into the path of movement of containers 10 along the feed line 15 so that they are operated by the containers coincidentally with the movement of pusher 19. Movement of the arm from its rest position opens the valves 41 and 44 and permits passage of pressure fluid. Pilot switches 41 and 44 are adjustably positioned to permit change in their sequence of operation.

In normal conditions during static rest condition of containers 10, the operating arm 41a of the pilot valve 41 is released and extends into the space between an adjacent pair of cans and valve 41 is closed. In this condition, flow of pressure fluid to the retractive end of cylinder 35 is blocked. Similarly, in the same static rest condition of containers 10, the arm 44a of pilot valve 44 is biased by a can thus rendering valve 44 open and pressure fluid from conduit 38 is admitted to conduit 45, T-head 46, conduit 47, air impulse relay 48 and conduit 49 into the forward stroke end of cylinder 35 causing forward projection of gripper 36 and its shoe 37 against the second, third and fourth lids above the bottom lid. The application of gripper 36 and its shoe 37 against the lids L thus prevents the lids L in the stack S above the bottom lid from moving downward.

OPERATION OF LID-DEPOSITING APPARATUS

Operation of valves 41 and 44 is as follows:

Assuming completion of filling of can 10b at station I, the level detecting mechanism at that station operating in the manner described in my aforesaid patent, activates the pusher cylinder 20 to project its pusher 19 and advance all the containers in feed line 15 a distance equal to the diameter of a single container. During this single step forward motion, the leading filled can in advance of station II in its forward movement moves against arm 41a of pilot valve to open the latter. Also, in this advance, the leading can beyond station II in its forward movement releases arm 44a of pilot valve 44, thus allowing valve 44 to return to its normally closed position. Thus, during this forward single step movement of the containers along the feed line, the retracting end of cylinder 35 will be supplied with pressure fluid causing a retraction of the gripper 36 and its shoe 37 to free the lids L in the stack. Positioning of arms 41a and 44a so that activation or deactivation occurs at the half-diameter position of single step container motion insures the required simultaneous operation of both valves. After movement created by pusher 19 has ended, the valves 41 and 44 return to the static rest condition as described above, wherein shoe 37 holds all lids L in place.

The effect of this control of operation of the cylinder 35 by said pilot valves is as follows:

Reverting to FIG. 2, it indicates the location of containers 10 along feed line 15 during static rest condition. Filled cans 10f and 10g are each about half-way under the lid depositing station II and the free bottom lid L ₁ is supported by lidded can 10g, although extending about 1/2 d over the open mouth of can 10f, as shown in FIG. 3. At this same time, shoe 37 is in engagement with the three lids L ₂ , L ₃ and L ₄ (FIG. 6) so that all lids above L ₁ in stack S are held against downward movement. At the filling station I, container 10a is being partially filled and the partial fill of container 10b is being completed. The pusher 19 at this time is in retracted condition. All containers 10 in the feed line 15 are in side-by-side abutment and the pusher 19 in its retracted state then abuts the hindmost container 10h.

As soon as the fill of container 10b at fill station I is complete and detected by sensing means 24, the latter causes the circuit in FIG. 8 to act on the cylinder 20 of pusher 19 to extend the pusher a distance equal to a diameter d of a container. This pushing action on container 10h is transmitted to all the abutting containers 10 in feed line 15 resulting in simultaneous advance of all the containers forwardly along feed line 15 a like distance d. During this advance, of cans 10, can 10f moves a distance equal to about 1/2 d under stack S to the position shown in FIG. 4, receives the lid L ₁ which had been extended over it and supported by can 10g, and then moves to the rest position shown in FIG. 5. During this advancement, by operation of valves 41 and 44, shoe 37 is retracted thus releasing the stack S of lids L. This release of stack S permits all of the lids in stack S to fall until they are supported by container 10f. Lid L 2 is thus also freed and it falls into void V. Thereafter, shoe 37 moves back into engagement with stack S and prevents lids L ₃ , L ₄ , etc. from moving.

Container 10f carrying its deposited lid L ₁ is free to move outwardly from under stack S because the lower ends of forward guide rods 31 and 32 are high enough above lid L ₁ as seen in FIGS. 3 through 6 to provide the requisite clearance, while being low enough to prevent freed lid L ₂ from moving out.

The same cycle then repeats for filled can 10b as it is moved through the position previously occupied by can 10f in FIGS. 3, 4 and 5 with the same coordinated operation and release of arms 41a and 44a of pilot valves 41 and 44. In succession, therefore, each filled container or can step-by-step in transit past the lid-depositing station II has a single lid deposited over its opening from the stack S. It is, of course, understood that the guide rods 29-33 are all adjustable vertically, the location of switches 41 and 44 are adjustably positionable along the feed line 15 as is the cylinder 20 of pusher 19 to provide needed adjustment for differently dimensioned containers, e. g. a quart size in lieu of a 1/2 gallon sized container.

Upon completion of deposition of lids successively upon containers at the lid-depositing station as just described, the containers having these lids continue to be moved step-by-step along feed line 15 beyond said station II to the lid press-down station III at which the previously deposited lid on each successive container is firmly pressed down into seated and sealing condition on such containers.

In the embodiment shown in the drawings, the lids L form a nested stack, i. e. each lid fits into the one beneath it. Accordingly, shoe 37 is retracted to release the stack of lids only at such time that the lid previously deposited on a container is moved sufficiently so that the released lowermost lid cannot nest with the lid already deposited on a container. With reference to FIGS. 3-5, this means that lid L ₂ cannot be released, i. e. the stack S cannot be released until container 10f is moved slightly from its position as shown in FIG. 4 in order to prevent lid L ₂ from nesting with lid L ₁ , the latter being already deposited on container 10f.

In addition, it is to be noted that it is necessary that shoe 37 move outwardly to engage lids 3, 4 and 5 prior to the time that container 10b moves directly beneath stack S or else more than one lid will drop or be deposited on container 10b. As indicated above, this is effected by arranging the sequence of operation of cylinder 20 so that pusher 19 and shoe 37 are in engaging position shortly after lid L ₂ drops into the space or void V.

Thus it can be seen that it is not necessary that the containers actually come to a rest position beneath stack S in order to derive the benefits of the present invention. It is necessary only that containers arriving at the lid-depositing station be in abutting relationship since it is the movement of the containers which creates the void space V into which the lowermost lid drops, and it is also the movement of the containers which actually sets the lid onto the next open container, there is no need for bringing the containers to a rest or static position. In fact, the rest or static position occurs in the embodiment shown above merely because of the manner in which the containers are moved along the container path. As an alternative to the embodiment shown in the drawings, it is possible to use the lid-dropping mechanism in a situation where the containers are on a moving conveyor which transports the containers up to and beyond the lid-depositing station. It is necessary only that means to provide the insurance that the containers beneath the stack S are in abutting relationship. This can be accomplished, for example, by having a reciprocally operated stop member moving across the path of the containers, timed in sequence with the operation of cylinder 20. In this manner, a pair of containers may be appropriately positioned beneath the stack S for a sufficient period of time to enable cylinder 20 and shoe 37 to operate reciprocally in order to free the lowermost lid which is then deposited on the open cylinder where the reciprocally operated stop member moves out of the path of the containers.

LID PRESS-DOWN APPARATUS

The lid press-down apparatus 18 located at station III along feed line 15 is seen in FIGS. 1, 2 and 7 and its control system is illustrated schematically in FIG. 10. The control system for apparatus 18 performs two functions:

1. A short time delay is provided so that the lidded cans can assuredly come to rest in apparatus 18 before the lid is pressed down.

2. A second time delay is provided in the press so that the travel of the piston which seals the lids is not a fixed length, but may vary in accordance with any variation in the height of the lidded filled cans.

This apparatus 18 in the embodiment shown comprises a framework of vertically spaced bars 55 and transverse spaced-apart bars 56 which latter are adjustably secured to the bars 55 above the feed line 15. A vertically extending pneumatic or hydraulic cylinder 57 is supported on the transverse bars 56 with its piston rod 58 extending downwardly. A pressure-exerting plate 59 is secured to the outer end of piston rod 58. This plate 59 has a large bottom plane surface 59a whose area and dimensions are substantially greater than the area and dimensions of the containers 10 and container lids L. A reinforcement plate or table 60 underlying feed line 15 below plate 59 may be provided.

The cylinder 57 carried by support bars 56 is positioned on the vertical bars 55 so that in the retracted position of piston rod 58 the surface 59a is elevated to a position substantially above the level of the containers 10 bearing deposited lids that are pushed by the action of pusher 19 successively step-by-step along feed line 15 and successively arrive under said surface. As each successive filled container 10 bearing a lid L deposited thereon arrives into a centered condition under the surface 59a, cylinder 57 is pneumatically or hydraulically activated to extend piston rod 58. This position of cylinder 57 is such that before completion of the outward stroke of piston rod 58, surface 59a engages the uppermost surface of the lid L of the container 10 centered under it. Because of the large area of surface 59a, the leading portion of lid L on the container 10b directly behind the centered container and the lagging portion of the lid L on the container 10g directly in advance of the centered container, as shown in FIG. 7, both underlie the said surface 59a.

As shown in FIG. 7, the leading portion of lid L on container 10b is pressed down by action of the oversize surface 59A. This results in a partial starting of lid L so that it is at an angle with a plane perpendicular to the vertical axis of container 10b. When container 10b moves directly under surface 59A for completion of the lid-pressing operation, the closure is effected in a manner which permits entrapped air to escape along the trailing edge of lid L. In other words, the lids are actually pressed down on to containers in a gradual operation starting at the leading edge of the container and moving across the trailing edge. If this were not done and the lid pressed in a downward direction with the same force and equal movement around the periphery of the container, splashing and damaging of the containers would probably result.

On completion of the outward stroke of piston rod 58, surface 59a, arm 67a will be activated to effect an opening of said valve and permit flow of air through it via a conduit 68a to an air control valve 68 and from the latter via conduit 69 into an air chamber 70. When chamber 70 reaches the desired pressure, pneumatically operated valve 72 is opened and air flows therethrough via conduit 73 to a manually operable on-and-off air valve 74 controllable by an operator at will. The second inlet of pneumatically operated valve 72 is also connected via conduit 102 to the pressure-containing conduit 66.

The combination of valve 67, valve 68, air chamber 70 and valve 72 provides a time delay of approximately one second, which may be varied as desired, from the time arm 67a is tripped to the time valve 72 is actuated. This time delay provides a margin of safety to ensure that the can beneath plate 59 has come completely to rest before piston rod 58 begins to move in a downward direction.

A conduit 75 connects the valve 74 to an air impulse relay 77. Conduit 78 connects the air impulse relay 77 to one side of a four-way valve 79. One outlet of valve 79 is connected by conduit 80 to one side of cylinder 57, and the second outlet of said valve 79 is connected by conduit 81 to the other (lower) side of cylinder 57. Valve 79 is connected via conduit 82 directly to conduit 66 so that pressure in conduit 66 from source 61 is always available.

A conduit 83 also connects pressure-containing conduit 66 to one side of a second pneumatic pilot valve 84 having an operating lever 84a. This valve is located in the path of travel parallel to the movement of piston rod 58, and is supported adjustably on a plate 85 secured to one of the frame legs 55 as by set screw 86 lying in a slot 87 of the support plate 88. With such support the operating lever 84a of the valve 84 projects into the travel path of a roller 89 carried on a vertical bracket arm 90 secured to extend upwardly of pressure plate 59.

The outlet of valve 84 is connected by conduit 91 to an air control valve 92 similar to air control valve 68. Conduit 93 connects air control valve 92 to air chamber 94 similar to air chamber 70. Conduit 95 connects chamber 94 to one inlet of pneumatically operated valve 96 similar to valve 72. A second inlet of valve 96 is connected by conduit 97 to pressure-containing conduit 66. The outlet of valve 96 is connected by conduit 99 to an air impulse relay 100 whose outlet is connected by conduit 101 to the opposite side of valve 79. A second time delay is provided by valve 84, valve 92, air chamber 94 and valve 96. The time delay provided by this combination of elements permits piston 58 to move in a downward direction until plate 59 engages the lidded can beneath it, and thus pressure will continue to be exerted over a period of time equal to the time delay. Thereafter, piston 58 moves upward to its retracted position. In this manner, the length of travel of piston 58 is independent of a distance variable so that all containers will be properly sealed even though one or two may be shorter than the others. Stated another way, this second time delay permits compensation for variation in height of the lidded cans.

OPERATION OF THE CONTROL CIRCUIT OF FIG. 10

In static condition, which is that requiring piston rod 58 to lie retracted in cylinder 57, the arm 67a of valve 67 extends into the space between a pair of adjacent containers 10 in the feed line and valve 67 is closed so that no pressure exists in the upper end of cylinder 57. At this same condition, the roller 89 engages the operating arm 84a of valve 84 opening it and thus permitting pressure from conduit 66 to flow through air control valve 92, air chamber 94, valve 72, air impulse relay 100 and conduit 101 to the chamber A of four-way valve 79 thus supplying actuating pressure to the lower end of cylinder 57 causing retraction of piston rod 58 and maintenance of its attached presser plate 59 in a normally elevated condition.

Upon arrival of a container 10 in centered condition under presser plate 59, the said container activates arm 67a of valve 67, opening the latter. In consequence, pressure from conduit 66 flows via air control valve 68, air chamber 70, valve 72, conduit 73, air impulse relay 77 and conduit 78 to the opposite side of four-way valve 79. This permits flow of air from conduit 822 through valve 79 and conduit 80 to the upper end of cylinder 57, thus causing piston rod 58 and with it presser plate 59 to be projected downwardly into pressing engagement with the lid L on the centered container 10 (e.g. 10f) for lid sealing and seating.

It is requisite that the position of the station III along the feed line 15 as well as switch 67 on feed line 15 must be such that operating lever 67a of said switch 67 will be activated to open said switch 67 at the time of arrival at centered condition of a container 10 (10f) under presser plate 59. Thus, it is manifest that requisite pneumatic operation of all the mechanisms at stations I, II and III are in effect controlled by positions of cans or containers in side-by-side contact on said feed line as they are advanced step-by-step by controlled operation of presser 19 whose action in turn is monitored by the fill-detecting system at station I. Moreover, during retractive condition of presser 19, the void left at the entrance to feed line 21 from the container delivery chute 14 is filled by the next succeeding empty container 10 therein which is pushed into it by rearward containers fed to it from turn-table 11.

A parallel-like system like that arranged adjacent the system just described and fed into a like feed line having like stations I, II and III can be disposed to provide container-filling, lid-depositing and lid press-down at respective stations, thus doubling the number of lidded sealed containers arriving at the conveyor beyond station III.

While a specific embodiment of the invention has been described and shown, variations in structural details within the scope of the appended claims are possible and are contemplated. There is no intention, therefore, of limitation to the exact disclosure herein presented.