Variable stroke lifting system

Abstract: A variable stroke lifting system for lifting a container 38 so as to surround a filler nozzle 40 for "bottom-up" filling thereof includes a pivotally mounted slide arm 58, a lift arm 12 operatively connected to the slide arm 58 for movement therewith, a plurality of different size cams 46, 48, 50, 52 and 54 and a follower 60 secured to the slide arm 58 for co-operation with the plurality of cams 46, 48, 50, 52 and 54 for raising the lift arm 12. The lift arm 12 lifts a container 38. A series of suitable actuator devices, such as air cylinders (68), serves to position the slide arm 58 and the follower 60 to engage selected cams 46, 48, 50, 52 and 54 for raising particular size containers 38 through the desired stroke length.

Description: This invention relates generally to apparatus for filling containers and, more particularly, to a lifting system providing differing stroke lengths for lifting different size containers to be filled by a "bottom-up" filling technique. For filling containers with liquids, it is well-known to use a so-called "bottom-up" filling technique in order to eliminate the build-up of foam. In this technology, either the filler nozzle is lowered into the container and then raised during the filling operation, or the container is lifted around the filler nozzle and then lowered during the filling operation, with the two separating at a rate commensurate with the flow rate of the liquid. When it is the container which is lifted and then lowered, it has been customary to employ either a vacuum system wherein a vacuum cup on the end of a vertical actuator engages the bottom surface of the container, or a system wherein a cross bar is mounted on the end of a vertical actuator, without a vacuum cup. The vacuum cup or the cross bar typically are mounted on the upper end of a stem connected to the end of an air cylinder piston. A satisfactory vacuum arrangement is shown and described in US-A-4,712,665. Various cam arrangements are also known for lifting a container from a shelf or conveyor to accommodate bottom-up filling thereof as the container is lowered from around a filler nozzle, for example, US-A-594,257; US-A-1,993,367; US-A-2,100,359; US-A-2,142,257; US-A-2,605,948; US-A-2,896,381; US-A-4,084,626; and US-A-4,388,795. Of the above-mentioned US-Patents, only two, namely, US-A-2,100,359 and US-A-2,142,257 disclose means for changing the lift height to accommodate different size containers, each includes a crank-disk side-by-side and integral with a single cam, with bolt-receiving apertures at different radii to vary the stroke of a pitman to accommodate different capacity containers. A prior arrangement for lifting containers to be filled is also known, wherein three or more cams are moved laterally as a group relative to a laterally fixed cam follower roller to bring the roller opposite to the camming profile of a selected cam. Also known is an arrangement having only two cams, which are both laterally fixed. A platform, which supports containers to be lifted, is mounted on a plate which is connected by a substantially vertical, elongate, universal or swivel connection to a lift arm which turns about a horizontal axis and is laterally slidable therealong. The lift arm is fixed to an arm carrying a cam follower roller which can bear on a selected one of the two cams. To shift the roller to the other of the two cams, the lift arm, and thus the arm carrying the follower, is shifted laterally, the connection following this movement. Such an arrangement becomes less and less practical the more cam profiles need to be selected from. According to the present invention, there is provided a lifting system for lifting different size containers from a holding device for bottom-up filling thereof by a filler nozzle, said system including pivotally mounted lift arm means for lifting said containers, pivotally and slidably mounted slide arm means operatively connected to said lift arm means for turning therewith, laterally fixed, rotatably mounted camming means having differing camming profiles, cam follower means mounted on said slide arm means, and actuator means for laterally moving said slide arm means with respect to said camming means thereby to reposition said cam follower means adjacent a different selected camming profile, characterized in that said lift arm means is laterally fixed and that said actuator means serves to move said slide arm means laterally with respect to said lift arm means. Owing to the invention it is possible to provide an improved lifting system for lifting different size containers to be filled by a bottom-up filling technique. Also owing to the invention it is possible to provide an improved cam-and-lever lifting system providing different stroke lengths for lifting different size containers to a position around a fixed filler nozzle to be filled with a liquid via a bottom-up filling technique. Further owing to the invention it is possible to provide a cam-and-lever lifting system including multiple cams for different resultant stroke lengths, wherein a bank of air cylinders or other suitable means are selectively actuated to position a slide arm and follower to engage a desired cam, with the slide arm slidably connected to a lift arm so as to lift the same and, thereby, to lift empty containers from a holding device, such as a pocket on a conveyor, to position the container with respect to a filler nozzle for filling with a liquid. In order that the invention may be clearly understood and readily carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which:- Figure 1 is side elevation of a container lifting system; and Figure 2 is a fragmentary top plan view taken along the plane of the line 2-2 of Figure 1, and looking in the direction of the arrows. Referring now to the drawings, a lifting system 10 includes a lift arm 12 pivotally mounted on an elongated pivot member 14 at an intermediate point therealong. The end 16 of the lift arm 12 is pivotally connected by any suitable means, such as a roller 18 in a camming slot 20 formed in a block 22, to a pair of parallel rods 24 and 26 extend upwardly from the block 22 for vertical movement therewith. A container indexing device (driving means not shown), represented at 28, may be pairs of upper and lower chains 32 and 30 with corresponding drive lugs formed thereon. Carton bottom guides 29 may be vertically positioned by any suitable external means (not shown) to suit different container heights. A lift bar 34 is adjustably mounted by any suitable means, represented at 36, at the upper end of the rod 24, to co-ordinate with the position of the carton guide 29 and to engage the bottom surface of a container 38 to raise the same to a position around a filler nozzle 40 to fill the container by the so-called bottom-up technique, i.e., lowering the container 38 from around the filler nozzle during the filling operation at a rate commensurate with the flow rate of the liquid. A retract-assist finger 42 is mounted at the upper end of the rod 26 to engage the upper edge of the container 38 while it is being lowered by the lift arm 12. If necessary, the height of the finger 42 may be adjusted for particular container heights by any suitable adjustment means, represented at 44. A guide member 45 serves to guide the rods 24 and 26 during their vertical movements. A plurality of cams 46, 48, 50, 52, and 54 are positioned alongside (Figure 2) and above (Figure 1) the lift arm 12. The cams are secured to shaft means 56 which is rotatably connected to suitable drive means (not shown). A slide arm 58 is slidably and pivotally mounted on the elongated pivot member 14, and slidably connected by any suitable connector means, represented at 59, to the lift arm 12 such that the latter moves vertically with the vertical movement of the slide arm, as will be described. A cam follower roller 60 is rotatably mounted on one end of the slide arm 58 adjacent the plurality of cams. A first of a series of suitable actuator means, such as servo-motor, manually operated threaded means, or, as selected for illustration, air cylinders 64, 66, and 68, is mounted on a base plate 70. The cylinder 64 is operatively connected to the slide arm 58 so as to extend or retract the cam follower 60, as required to selectively engage respective cams 46, 48, 50, 52 and 54. If air cylinders are used, the sequence of cam engagements and, hence, lift arm 12 operation, with respect to respective cylinder 64, 66 and 68 actuations would vary from all three cylinders being extended, for example, to align the follower 60 with the furthermost cam 46, to all three cylinders being retracted to align the follower 60 with the first-in-line cam 54. An air cylinder 72 (Figure 1) is connected at the upper end thereof to a seat 74, while the piston 76 thereof is secured to an end rod 78 which is pivotally mounted on the lift arm 12 intermediate the pivot member 14 and the end 16. Inasmuch as the slide arm 58 is secured for vertical movement with the lift arm 12, the air cylinder 72 secured to the latter arm serves, when retracted, to retain the cam follower 60, which may be a roller rotatably mounted on the slide arm 58, against any selected one of the cams 46, 48, 50, 52, and 54 while the cams are being rotated to thus lift and lower the lift arm 12. When extended, the air cylinder 72 serves to hold the cam follower 60 away from the respective cams for realignment via the slide arm 58 with a different cam. The position of the retract-assist finger 42 (Figure 1) is adjustable relative to the lift bar 34, such that the highest lift position thereof may vary for respective container 38 sizes, while its lowest position may be a common position for all container sizes. The corresponding highest and lowest lift positions for the lift bar 34 may be such that the highest position thereof is common for all container 38 sizes, and the lowest position thereof variable. Where necessary, for a particular container 38 height, any of the cams may, of course, be shaped to produce different highest and lowest lift positions. As shown rotated 90° in Figure 1, a cylinder 80 includes a piston 82 having adjustable stops 83 mounted on the distal end thereof, suitable for particular container sizes, and selected to complement the motion provided by a corresponding cam 46, 48, 50, 52 or 54. The selected stop 83 abuts against the rear end 84 of the slide arm 58, adapted to limit the extending ability of the air cylinder 72. For each container 38 size, the cylinders 64, 66 and 68 are actuated as required to reposition the cam follower 60 adjacent a selected cam 46, 48, 50, 52 or 54. While repositioning, the cylinder 80 is retracted to prevent interference between the stop 83 and the end 84. Thereafter, as the newly selected cam is rotated, as may be determined from a review of Figure 1, the container of a particular size will be lifted vertically through a particular stroke length to its highest lift position by the resultant vertical movement of the lift bar 34. In the event that no container 38 is present during any cycle, the air cylinder 72 is programmed to extend and hold the follower 60 away from a cam, and thereby cause the lift arm 12 to remain stationary. Simultaneously, the filler nozzle 40 will not be actuated. It should be apparent that the embodiment described with reference to the drawings provides an efficient, compact lifting system through different selected stroke lengths for lifting different size containers to be filled by a bottom-up filling technique. It should also be apparent that the number and sizes of cams in the system may vary to coincide with the number of different size containers which are to be filled. It should also be realised that the lift bar 34 at the upper end of the rod 24 may be of a length sufficient to lift two or more aligned containers to accommodate two or more filler nozzles, such as on a double or quadruple track forming, filling and sealing machine.

Claims: A lifting system for lifting different size containers (38) from a holding device for bottom-up filling thereof by a filler nozzle (40), said system including pivotally mounted lift arm means (12) for lifting said containers (38), pivotally and slidably mounted slide arm means (58) operatively connected to said lift arm means (12) for turning therewith, laterally fixed, rotatably mounted camming means (46-54) having differing camming profiles, cam follower means (60) mounted on said slide arm means (58), and actuator means (64,66,68) for laterally moving said slide arm means (58) with respect to said camming means (46-54) thereby to reposition said cam follower means (60) adjacent a different selected camming profile, characterized in that said lift arm means (12) is laterally fixed and that said actuator means (64,66,68) serves to move said slide arm means (58) laterally with respect to said lift arm means (12). A lifting system according to claim 1, wherein said holding device is a pocket formed by pairs of lugs of a conveyor chain. A lifting system according to claim 1 or 2, wherein said lift arm means (12) includes a pivotally mounted lift arm (12), a vertically oriented lift rod (24) mounted on the lifting end of said lift arm (12), and a lift bar (34) operatively connected to the rod (24) for engaging the bottom surface of the container (38) to lift the same. A lifting system according to claim 3, and further comprising a second rod (26) parallel to said lift rod (24) and having a retract-assist finger (42) formed at the upper end thereof adapted to engage the upper edge of the container (38) to assist the same during a retraction operation after the container (38) has been filled. A lifting system according to any preceding claim, and including retaining means (72) for retaining said cam follower means (60) against a selected camming profile. A lifting system according to claim 5 as appended to claim 3, wherein said retaining means (72) is an air cylinder (72) having an upper end thereof fixed and a lower end thereof operatively connected to said lift arm (12) intermediate said lift rod (24) and said cam follower means (60). A lifting system according to any preceding claim, wherein the highest lift positions for all differing camming profiles are at a common level, with the camming profiles co-ordinated to provide stroke lengths resulting in differing levels for the lowest lift positions for the differing camming profiles. A lifting system according to any preceding claim, wherein said actuator means (64, 66, 68) includes a series of a plurality of air cylinders (64, 66, 68) whereof selected respective extensions and retractions co-ordinate the positioning of said slide arm means (58) to position said cam follower means (60) for engaging particular camming profiles. A lifting system according to claim 8, wherein a first camming profile in a series of said camming profiles is engaged by said cam follower means (60) when all of said plurality of air cylinders (64, 66, 68) are extended, a last camming profile in said series is engaged when of all of said plurality of air cylinders (64, 66, 68) are retracted, and intermediate camming profiles in said series are respectively engaged when said plurality of air cylinders (64, 66, 68) are simultaneously selectively extended and retracted. A lifting system according to any preceding claim, wherein said cam follower means (60) comprises a roller (60).

Inventors: DRURY TIMOTHY HOWARD, OWEN BARRY CHARLES, DRURY, TIMOTHY HOWARD, OWEN, BARRY CHARLES
Applicants: ELOPAK SYSTEMS, ELOPAK SYSTEMS AG
Application year: 1992
Main classification: B65B43
IPC codes: B67C3, B65B59, B65B43