Abstract:
A dual cam configuration is provided in a container filler machine. The filler machine preferably fills containers from their bottoms and includes at least one filling station assembly, each such assembly including a dispensing assembly and a positioning assembly. For controlling the filling process at each station, the cam configuration includes first and second cam tracks, each track being followed by a cam following assembly. For each station, the machine also preferably includes a single pneumatic cylinder assembly for simultaneously maintaining both cam following assemblies against their respective cam tracks.

Description:
FIELD OF THE INVENTION 
     The present invention relates to machines for filling containers with a desired product. 
     BACKGROUND OF THE INVENTION 
     Many specialized commercial high volume container filling machines such as can or bottle fillers are in many ways unduly complex. This is especially true of container filling devices that dispense a flowable product into a container but which also must satisfy some additional constraint such as dispensing the product into the bottom of the container, keeping the dispenser submerged while dispensing, or precisely measuring the amount of product to be dispensed into containers. In general, increased complexity leads to increased costs associated with filling machine operation. Greater costs for such machines can be attributable to setting the desired positions of various assemblies for a given container to be filled. Difficulties can also arise in making adjustments during operation. 
     In a typical container filling machine there are a plurality of continuous cam tracks providing a predetermined path that is followed by a plurality of &#34;filling stations&#34; such that each such station is designed to fill a single container with each cycle through the cam track path. The cam tracks must be designed and adjusted for each container&#39;s dimensions. In connection with some filling machines there are various spring tensions or pneumatic pressures that must be maintained to properly dispense products into the containers. 
     In U.S. Pat. No. 3,189,062 of KaZmierczak a liquid bottle filler is disclosed with a plurality of filling stations for precisely filling bottles with a liquid substance. The apparatus disclosed includes five cam tracks, and, for each bottle filling station: four cam followers, at least two springs and a cylinder/piston dispensing combination. Of the four cam followers, one rides between two cam tracks and causes the product dispenser nozzle to be lowered to the bottle opening for product dispensing and raised once dispensing has been completed. One of the two springs, a compression spring, is used in conjunction with this follower to provide shock absorption as the dispenser descends to contact the bottle opening. The second spring, a tension spring, supplies a force to the filling station dispensing piston in a direction causing the surrounding cylinder to remain filled with the substance to be dispensed. In addition, this second spring also urges a pair of filling station cam followers against their related cam tracks. One of these tracks causes the dispensing piston to dispense the bulk of the product while the second track causes the piston to dispense precisely the amount required. Finally, a fourth station cam follower governs a valve allowing the product to flow into the bottle to be filled. 
     In U.S. Pat. No. 3,559,702 of Riesenberg a liquid bottle filler is disclosed such that the dispensing process results in minimal substance turbulence. More precisely, the Riesenberg apparatus fills bottles with a liquid product by inserting a filling stem into each bottle for dispensing the liquid near the bottom of the container and once there is sufficient liquid in the bottle, the stem outlet remains submerged while being slowly withdrawn from the bottle thus providing a smooth non-turbulent flow of liquid into the bottle. The filling controls for this apparatus consists of two cam tracks, and, for each bottle filling station contained in the apparatus: at least four pneumatic cylinders, three with positive pressure, one with negative pressure. 
     In U.S. Pat. No. 4,838,326 of Colacci et al. an apparatus is disclosed for dispensing a flowable product into containers at high speed as the containers travel in a straight line on an adjacent conveyor. Although no special constraints are imposed upon the dispensing mechanism, the apparatus still requires five cams tracks, numerous pneumatic cylinders to press the top cam track against the filling station cam rollers as they come in contact with this track. In addition, each filling station requires: two cam followers, a piston/cylinder dispensing combination and a latching mechanism to keep the filling stations tightly sealed to one another as they are filled with the product. 
     There are also well known apparatuses, called &#34;bottom fillers,&#34; for dispensing a flowable or viscous product into the bottom of containers in a manner for reducing the development of air pockets in the container. Most bottom fillers require four circular cam tracks, and, for each filling station: two cam followers and a cylinder/piston combination for dispensing the product. For each filling station, the dispensing piston is surrounded by its sleeve or cylinder. The piston is allowed to reciprocate within the sleeve. Thus, the piston can be forced to retreat to one end of the sleeve as a pressured amount of product is allowed to fill the sleeve. Subsequently, the piston is forced in the opposite direction as the product is dispensed into the bottom of a container. The formation of air pockets is reduced in a container during the filling process since the sleeve can move independently of the dispensing piston and thus the product filled sleeve can be inserted into the bottom of the container prior to the piston expelling the product from the sleeve. Independent movement of the piston and the sleeve is achieved by the two pairs of cam tracks mentioned above. One pair is used to control the movement of each dispensing piston. The other pair is used to control the movement of each dispensing sleeve. For a given dimensioned container, each of the four tracks typically has a unique contour. Thus, substantial labor can be involved in initially positioning and/or subsequently adjusting all four tracks for appropriate container filling. Moreover, because the cam followers are sandwiched between tracks, such bottom fillers typically cannot easily provide a &#34;no-container, no-fill&#34; mechanism. That is, it is not feasible to stop the filling step when a can is missing because the four track configuration does not lend itself to such control 
     It would be advantageous to have container fillers that are both less complex to manufacture and require less labor to operate and maintain than those currently available. The present invention dynamically positions the dispensing mechanism within a container in a simple flexible manner. Embodied in an improved bottom filler, the apparatus requires only two cam tracks. One cam track for positioning the dispenser within the container and one cam track to cause an appropriate amount of product to be dispensed into the container. Furthermore, for each filling station, preferably a single pneumatic assembly supplies all the tension or pressure required for controlling the dispensing mechanism. 
     SUMMARY OF THE INVENTION 
     The present invention relates to a method and an apparatus for filling containers wherein each product dispenser can be dynamically positioned within the container while dispensing the product. The invention provides a novel dual cam configuration wherein two cam tracks control the dispensing operation for a plurality of container filling stations. Each filling station includes a product dispensing assembly. Each such assembly includes both a dispenser for delivering a predetermined amount of product into a container, and a positioning mechanism for positioning the dispenser during delivery. The dispenser is controlled by one of the cam tracks, the dispensing cam, while the positioning mechanism is controlled by the other cam track, the positioning cam. Thus, for each filling station, the dual cam configuration, in addition, includes a pair of cam follower assemblies. As each filling station traverses a predetermined path within the container filler, one such assembly follows the contour of the dispensing cam and therefore, via appropriate connectors, controls the dispenser. The other assembly follows the contour of the positioning cam and therefore, via appropriate connectors, controls the positioning mechanism. In following their respective cams, each cam following assembly includes a cam roller for rotationally contacting and following the cam. In addition, each filling station includes preferably a single fluid pressure device that is also part of the dual cam configuration. The fluid pressure device is incorporated into each filling station in such a manner as to simultaneously urge both cam rollers against their respective cams. Thus, as the filling stations traverse their designated path during operation of the container filler, station cam followers follow the contour of their respective cams and therefore cause the product to be dispensed into containers. 
     In a preferred embodiment, a pneumatic cylinder embodies the fluid pressure device for each filling station. The cylinder supplies a separating force that urges the cam follower assemblies including their cam rollers in substantially opposite directions. The cam tracks are positioned such that the separating force causes the cam rollers to be urged against their respective cam tracks. The cam tracks must be positioned such that the direction of force exerted on their respective cam rollers urges the rollers against the appropriate cam track. In another embodiment, the fluid pressure device can be embodied as a compression spring. However, the preferred pneumatic cylinder has the advantage that the pressure or tension can be easily adjusted or eliminated entirely during cam adjustments. 
     When the preferred dual cam configuration is incorporated into a bottom filler, the resulting design provides significant advantages over previous bottom fillers. In particular, the following advantages accrue: 
     a. A &#34;no-container, no-fill&#34; feature can be more readily incorporated into the bottom filler. Since neither cam follower is locked between two cam tracks, the piston/sleeve dispensing combination can be locked in a position such that the sleeve does not receive the product during the sleeve filling step or phase. 
     b. The cams and cam followers last substantially longer since there is only a single track that the follower must contact. 
     c. The filling stations are more easily cleaned. Bottom fillers with four cam tracks are supported by a cam track frame that surrounds the bottom filler. Thus, cleaning the filling stations is at least awkward and can necessitate dismantling some portion of the cam frame and/or its cams. 
     d. The improved bottom filler is quieter during operation. Since each cam follower is virtually always in contact with its cam track, the noise associated with cam followers oscillating between a pair of tracks is eliminated. 
     e. Assembly and adjustment of the cam tracks is more readily accomplished since there are only two tracks and a set distance between a double cam configuration for proper roller clearance is not necessary. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will be better understood from the detailed description given below and the accompanying drawings which are given by way of illustration only, and thus, are not limitative of the present invention and wherein: 
     FIG. 1 is a perspective view of the bottom filler machine illustrating the two cam tracks and the pneumatic cylinder assembly; 
     FIG. 2 is a more detailed perspective view of the pneumatic cylinder assembly and attachments for achieving the separating force; and 
     FIG. 3 is a diagram illustrating the cycle of the bottom filler machine when filling a container 
    
    
     DETAILED DESCRIPTION 
     With reference to FIG. I, a preferred embodiment of the invention is presented as container filler machine I0. The base of the container filler machine I0 includes a circular container star wheel 14 for positioning a plurality of containers 18 in a circular fashion equally spaced around the star wheel 14. FIG. 1 shows two such containers 18. Each container 18 is cylindrical and is oriented such that the open end is facing upward. A product dispensing assembly 24 is positioned above each container on the star wheel 14. The assembly 24 includes: a vertically movable product positioning sleeve 36 for containing the product 16 immediately prior to being deposited into a container 18, a piston head 40 movably fitted within sleeve 36 for pushing the product 16 in sleeve 36 downward into container 18, a piston shaft 44 for supplying a downward force to piston head 40 to which shaft 44 is connected, a vertically stationary dispenser casing 32 snugly surrounding sleeve 36 and a dispenser bushing housing 28 resting upon and attached to casing 32 such that housing 28 surrounds the upper portion of sleeve 36. As shown in the cutaway portion of FIG. 1, each dispensing assembly 24 protrudes through and is supported by a circular support plate 48. A flange 52 bottoms out on top of the plate 48. The container star wheel 14 and the plate 48 have their centers on a vertical axis that is also coincident with the vertical axis of the central column 56. Although not shown, the central column 56 penetrates and supports both plate 48 and star wheel 14 such that they can rotate about column 56. Thus, column 56 also indirectly rotatably supports the dispenser assemblies 24. 
     The upper end of shaft 44 of each assembly 24 is connected to a cam follower assembly 60. When rotating about column 56, cam follower assembly 60 follows the bottom contour of stationary circular cam assembly 64. Thus, the contour of cam assembly 64 ultimately determines when piston 40 is forced downward to deposit a predetermined amount of product 16 in a container 18. Circular cam assembly 64 includes adjustable arcuate cam tracks 68, well known in the art. Each cam track 68 is adjustably attached to cam supports 72 arranged circularly around column 56 and supported by an outer container filler machine 10 framework (not shown). 
     Returning to cam follower assembly 60, as best illustrated in FIG. 2, each assembly 60 includes a cam roller subassembly 76 containing a plurality of rollers 84 and a roller bracket 80 to which the cam roller subassembly 76 is attached In the current embodiment, the cam roller subassembly 76 includes three rollers 84 held by bracket 80 and a single safety roller 88 held outside of bracket 80. All four rollers are in line and rotate independently about the same axle (not shown). In certain abnormal circumstances as explained below, e.g. the loss of air to the system, the roller 88 will follow the top contour of safety cam 92 (FIG. 1). In normal operation, at least one of the rollers 84 follows a cam track 68 of cam assembly 64 and roller 88 will not be used. 
     For each cam follower assembly 60, there is a single pneumatic cylinder 90 supplying the force urging the rollers 84 against cam 64. This cylinder is preferably supplied with pressurized air via supply line 94 from air pressure source 98. As best disclosed in FIG. 2, cylinder 90 is removably attached to connector 102 by fastener 106 being threaded onto cylinder bolt fitting 110 using a washer 112. The washer 112 underlies the slot defined by the two fingers of the connector 102. Connector 102 is removably attached to bracket 80 via some suitable means, for example, bolts 108. Since there are both upward and downward vertical forces applied to connector 102, as will be discussed below, connector 102 is appropriately reinforced by flanges 114 disposed between the horizontal and vertical members of connector 102. To assure that cylinder 90 maintains a vertical orientation and is also firmly connected to connector 102, two alignment stays 118 are identically and removably attached to opposing sides of connector 102 via bolts 122. These alignment stays 118 are designed such that an amount of torque placed on the pneumatic cylinders, after bolt 106 has been loosened, causes sufficient deflection in the alignment stays 118 whereby the pneumatic cylinders can be removed and set aside for station clean-up Protruding horizontally from the lower portion of cylinder 90 are two alignment stops 126. Each of the stops 126 fits tightly into a stop seat 130 of each alignment stay 118. Any upward force exerted on cylinder 90 will cause alignment stops 126 to exert a force on stop seats 130 thus causing cylinder 90 to maintain a vertical orientation. Protruding from the lower end of cylinder 90 is a movable cylinder rod 134. This rod is forced downward, out of cylinder 90 by the pressurized air within cylinder 90. The lower end of rod 134 is suitably attached to a cam follower assembly 138 via rod attachment 142. A cam roller 146 is connected to the rod 134 and, in normal operation, is urged downward by the rod 134. As shown in FIG. 1, cam follower assembly 138 follows the contour of stationary circular cam assembly 150 as rod 134 and cylinder 90 rotate about column 56 in unison with dispenser assembly 24 and cam follower assembly 60. Cam follower 138 includes axle 154, shown best in FIG. 1. The outermost end of axle 154 operates to rotatably support cam roller 146 and therefore follows the contour of cam assembly 150. The opposite end of axle 154 extends through housing 28 via vertical slot 158 and is affixed to sleeve 36 such that the vertical position of sleeve 36 is determined by the vertical position of axle 154 and thus indirectly by cam assembly 150. Returning to cam assembly 150, it includes adjustable cam tracks 162, in a similar fashion to cam assembly 64. Cam assembly 150 is supported and held stationary by a plurality of cam supports 166, one of which is shown in FIG. 1. Supports 166 are suitably attached to cam assembly 150 and to the outer container filler machine 10 framework (not shown). 
     Since the combination, including a dispenser assembly 24, its uniquely associated cylinder 90, rod 134, connector 102, cam follower assembly 60 and cam follower assembly 138 function as a container filling unit, it is useful to refer to each combination as a &#34;filling station&#34; 170 (FIG. 1). Thus, each filling station 170 operates independently of others and rotates about column 56 with both cam follower assemblies 60 and 138 being urged by the air pressure contained within a single cylinder 90 to follow the contour of cams 64 and 150 respectively. 
     During normal operation of container filler machine 10, a plurality of product filling stations 170 are urged to rotate continuously about column 56 by a suitable power source not illustrated. During each rotation, each station 170 cycles through at least five phases. These phases are illustrated in a simplified manner in FIG. 3. For illustration purposes, FIG. 3 presents the cam assemblies 64 and 150 as rails or tracks and a filling station 170 is represented by only its sleeve 36, piston head 40 and cam follower assemblers 60 and 138, together with their related piston shaft 44 and rod 134 respectively. During phase 3.1 the product 16, under pressure, is urged into the sleeve 36 while initially piston head 40 is flush with the lower end of sleeve 36. As product 16 begins filling the sleeve 36, piston head 40 moves upward, thus urging shaft 44 and cam follower assembly 60 upward. The upward movement is allowed since cam assembly 64 or portion control is configured to provide a predetermined control height corresponding to the amount of product 16 that is to be deposited in a container 18. During phase 3.2 the product filled sleeve 36 is sealed off at the bottom by a suitable means to prevent product loss while an empty container 18 is aligned beneath the sleeve 36. During phase 3.3 both the sleeve 36 and the piston 40 are synchronously forced downward relative to the container 18, which is positioned below the filling station 170. The downward urging is accomplished by followers 60 and 138 following cams 64 and 150 respectively. Note that sleeve 36 has a diameter small enough to allow it to fit into container 18 and allow air within the container to escape as the product filled sleeve 36 moves to the bottom of the container 18. In phase 3.4, cam follower 60 continues somewhat further downward causing piston 40 to continue downward while follower 138 moves upward causing sleeve 36 to retract from container 18. Thus, the product 16 is forced out of sleeve 36 and piston 40 compacts product 16 sufficiently to remove any remaining air. In phase 3.5, both cam followers 60 and 138 follow their respective cams upward. Both the piston 40 and the sleeve 36 retract completely clear of the product filled container 18. Thus, the container 18 can now be removed from container filler 10 while sleeve 36 and piston 40 remain in this last position in preparation for phase 3.1 to once again commence. 
     It can be seen from the above description that each filling station 170 has a single pressurized cylinder 90 providing the separating force causing both cam followers 60 and 138 to follow their respective cams as the station rotates through the phases of FIG. 3. That is, as the pressure in cylinder 90 forces rod 134 to extend downward causing follower 138 to press against cam 150, the result is an equal and opposite force that is directed upward. This upward force on cylinder 90 is conveyed to connector 102 via the cylinder attachments: fastener 106 and stays 118. However, since connector 102 is firmly attached to bracket 80 of cam follower 60, this upward force is transferred to follower 60 causing cam roller subassembly 76 to follow cam 64. It should also be noted that the pressurized air of cylinder 90 can be constant as station 170 rotates through the phases of FIG. 3. All that is needed is sufficient pressure to keep followers 60 and 138 in constant contact with their respective cams. Thus, the fluid pressure supplied to each pressure source 98 can be independent of container filler machine 10 since there is no need to coordinate cylinder 90 pressure with any container filler machine 10 actions. 
     In the event that a cylinder 90 looses pressure, the current embodiment of container filler machine 10 requires that both the sleeve 36 and the piston 40 remain above the support plate 48 during the product filling phase 3.1, the container 18 positioning phase 3.2 and the container 18 removal period which can be concurrent with phase 3.5. If this requirement is not met, severe damage to the container filler machine 10 may occur. In the case of the sleeve 36, note that since the cam follower 138 to which it is connected is supported by cam 150, there is no possibility of sleeve 36 remaining below plate 48 at inappropriate times. However, this is not the case for piston 40. Without the upward force derived from the pressure in cylinder 90, follower 60, shaft 44 and piston 40 have only frictional and gravitational forces applied to them. Thus, there is the possibility piston 40 could extend through plate 48 at an inappropriate time due to gravity. To stop this possibility from occurring, safety cam 92 is positioned such that as cam follower 60 falls away from cam 64, the safety roller 88 will contact the top of safety cam 92, thus preventing unwanted movement of the piston 40 below plate 48. 
     It should be understood that the dual cam configuration embodied in separating force cylinder 90, cam followers 60 and 138, and cams 64 and 150 need not apply only to container filling apparatuses that include a dispensing assembly 24 such as embodied in FIGS. 1 and 3. That is, such a dual cam configuration can be used wherever a container filler dynamically positions the dispenser mechanism during a container filling operation. For example, the dual cam configuration can be utilized in canning devices, bottle filling devices, or drum filling devices. 
     It is also noted that the separation force provided by cylinder 90 could, instead, be provided by a mechanical means such as a spring means. 
     The foregoing discussion of the invention has been presented for purposes of illustration and description. Further, the description is not intended to limit the invention to the form disclosed herein. Consequently, variations and modifications commensurate with the above teachings, within the skill and knowledge of the relevant art, are within the scope of the present invention. The embodiment described hereinabove is further intended to explain the best mode presently known of practicing the invention and to enable others skilled in the art to utilize the invention in such, or other embodiments, and with the various modifications required by their particular applications or uses of the invention. It is intended that the appended claims to be construed to include alternative embodiments to the extent permitted by the prior art.