WEIGHT FILLING MACHINE FOR BOTTLES

Abstract: A weight filler 6 is provided which allows a bottle 16 to be conveyed while gripping its neck 16a. Load cell 58 is mounted around the outer periphery of a revolving body 54 in order to detect a vertical load. A horizontal rod or load applicator 64 projects radially outward from the load cell 58. A gripper 50 which grips the bottle 16 under the resilience of tension springs 82 is mounted on the free end 64a of the rod 64. As the bottle 16 is urged into the gripper 50 in a direction opposite from the direction in which the rod 64 projects, the gripper 50 is once opened against the tension springs 82 and then closed to grip the neck 16a of the bottle 16. A filling nozzle 52 is disposed above the bottle 16 which is gripped by the gripper 50, and fills the bottle 16 with liquid. During the filling operation, the load cell 58 detects a load applied, thus allowing a filling of a given amount in accordance with the detection.

Description: BACKGROUND OF THE INVENTION AND RELATED ART STATEMENT The invention relates to a weight filler which fills a vessel while measuring its weight by means of a load cell. A conventional weight filler comprises a plurality of bottle mounts circumferentially spaced apart at an equal spacing around the outer periphery of a revolving body, a plurality of load cells mounted on the revolving body and each connected to one of the bottle mounts to measure the weight of a particular bottle on the bottle mount, and a plurality of filling nozzles mounted above respective bottle mounts, the arrangement being such that as a bottle is fed to each bottle mount, the associated filling nozzle fills the bottle with liquid while measuring the weight thereof by means of the load cell during the time the bottle is conveyed rotatively as the revolving body rotates (see, for example, Japanese Laid-Open Patent Application No. 154, 501/1992). Resin bottles, in particular, PET bottles which find extensive application as liquid filled vessels are very light in weight and unstable, and thus cannot be rapidly conveyed by using a usual conveyor without undergoing a considerable amount of difficulty. Accordingly, their necks are formed with flanges, which are supported from the underside. Alternatively, their necks are carried by grippers for purpose of conveyance of the bottles. In a filling system in which the filling operation takes place while the bottle necks are being carried, a bottle which is conveyed on a pneumatic conveyor, for example, has its neck gripped by a gripper of an introduction wheel to be handed over to 2 gripper of a filler where it is rotatively conveyed while a filling nozzle fills it with liquid, and the bottle is then handed over to a bottle processor such as a capper through an intermediate wheel which transfers it while carrying it by its neck. After desired processing operations are completed, it is discharged onto a delivery conveyor to be fed to a subsequent step. A processing system which utilizes neck-carrying conveyance performs the conveyance on the basis of the height of the neck of the resin bottle which is being carried, and exhibits an excellent flexibility in that there is no need for the adjustment of elevations of various processors, conveyor and wheels if it is used with bottles of varying size. However, as mentioned above, the conventional weight filler is constructed such that the measurement and the filling of the bottle take place after it is once placed on the bottle mount connected to the load cell. Accordingly, if the weight filler is assembled into this system, there arises a problem that the bottle which has been subject to the neck-carried conveyance must be once released from the gripper onto the bottle mount. As a consequence, if the conveying and processing system combined with the conventional weight filler is to be used with bottles of varying size, an adjustment of elevation of the conveyor and the like is required, which is difficult to accommodate. OBJECT AND SUMMARY OF THE INVENTION It is an object of the invention to provide an improved weight filler for use with conveying and processing systems for resin bottles having a neck and a flange spaced from the upper end of the neck which allows the bottle to be filled with liquid while gripping the bottle neck for conveyance. The invention is as defined in the accompanying claims, claim 1 of which has been divided into a two-part form based on the assumption that a relevant document, namely WO99/22209, can be considered to be the nearest state of the art. Thus all of the features defined in the precharacterizing part of claim 1 are known from the aforesaid document. The above object is achieved by providing a weight filler for filling a bottle having a neck, said neck having a flange spaced from the upper end of said neck; the weight filler having a load cell installed to detect a vertical load; the load cell having a load applicator horizontally projecting from the load cell; grip means supported by said load applicator and serving, when the bottle is driven inward in a direction which is opposite from the direction in which the load applicator projects from the load cell, to resiliently grip the neck of the bottle below said flange; a filling nozzle for filling the bottle when it is gripped by the grip means; the arrangement being such that a given amount of liquid is filled into the bottle which is gripped by said grip means while detecting the load by means of the load cell; characterized by: there being a neck support plate mounted on the load applicator at a location vertically offset above the location of said grip means, with an arcuate recess formed in a front end face of the neck support plate configured to abut the neck of the bottle above said flange to maintain the bottle in a stable manner whilst it is being filled. Additionally the grip means may be mounted on the load applicator in a manner to be rotatable within a horizontal plane for resiliently gripping a neck of the bottle, there being restriction means for maintaining the load applicator and the grip means in a given position relationship to restrict a relative rotation thereof and for releasing the restriction in response to a load in excess of a predetermined value, and a filling nozzle for filling the bottle gripped by the grip means with liquid, a given amount of liquid being filled into the bottle gripped by the grip means while detecting the load by the means of the load cell. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a plan view illustrating an entire conveying and processing system for resin bottles including a weight filler according to one embodiment of the invention; Fig. 2 is a longitudinal section, showing an essential part of the weight filler of the embodiment; and Fig. 3 is a plan view of Fig. 2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A weight filler according to the invention will be described below with reference to an embodiment thereof shown in the drawings. Initially, an overall arrangement will be described briefly with reference to Figs. 1 and 2. A bottle feed conveyor 2 conveys, as by pneumatic conveyance, a resin bottle 16 (see Fig. 2), the neck 16b of which is gripped by a gripper 84 on an introduction wheel 4 to be rotatively carried until the bottle reaches a hand-over position C where it is handed over to a gripper 50 of a weight filler 6. As will be described later, the gripper 50 of the weight filler 6 resiliently holds the underside of a flange 16c formed on the neck 16b of the bottle 16, and rotatively conveys the latter while suspending it. In the weight filler 6, a filling nozzle 52 which is located above the resin bottle 16 gripped by the gripper 50 fills the bottle 16 with liquid during the time when the gripper 50 conveys it while holding the underside of the flange 16c of the resin bottle 16. The resin bottle 16 which is internally filled with liquid is handed over to the capper 10 through an intermediate wheel 8, and after it is capped, the bottle is delivered through a delivery wheel 12 onto a delivery conveyor 14 to be fed to the succeeding step. It should be noted that the neck carrying conveyance which takes place while gripping the neck (or the cylindrical portion 16d of a reduced diameter) of the resin bottle 16 or supporting the underside of the flange 16c formed on the neck also takes place at each of the intermediate wheel 8, the capper 10 and the delivery wheel 12. The weight filler 6 will be described in more detail with reference to Figs. 2 and 3. The weight filler 6 includes a revolving body 54 which rotates in a horizontal plane about a vertical axis, not shown (which is assumed to be located to the right of Fig. 2), and a load cell 58 is mounted toward the outer periphery of the revolving body 54 through a vertical mounting plate 56. A box 60 is mounted on an upper portion of the vertical mounting plate 56 and includes a horizontal stationary base 62 on which one end 58a of the load cell 58 or the end disposed radially inward of the revolving body 54 is fixedly mounted while the other end 58b is supported in a manner floating over the stationary base 62. A rod or load applicator 64 which projects horizontally along a radial line of the revolving body 54 is mounted on the other end 58b of the load cell 58 for detecting a vertical rod applied to its free end 64a. On its front side, the box 60 is formed with a large opening 60a for avoiding an interference in the event of occurrence of flexure of the rod 64, the opening 60a being covered by a cover 66. A gripper mounting block 68 is fixedly mounted on the free end 64a of the rod 64 and has a lower surface in which one end of a vertical support shaft 70 is inserted and fixedly connected. The lower end of the support shaft 70 is rotatably connected with a neck support plate 72, the front surface of which is formed with a semi-arcuate recess 72a (see Fig. 3) having an interval diameter which substantially coincides with the external diameter of a thread 16a of the bottle 16. A shear pin 74 extends between the lower surface of the gripper mounting block 68 and the upper surface of the support plate 72 to restrict a relative rotation between the block 68 and the plate 72. The shear pin 74 is designed to break in response to a rotational load in excess of a predetermined value applied to the neck support plate 72, thereby allowing the support plate 72 to rotate. A pair of vertical pivot shafts 76 are fixedly mounted in the lower surface of the neck support plate 72 at locations which are symmetrical to the center line O 1 of the plate 72 (see Fig. 3). One end of each arm 78 is rotatably mounted on each pivot shaft 76 through an interposed bearing 80. The both arms 78 are normally urged toward each other by tension springs 82. Free ends 78a of the both arms 78 are notched in a tapered manner to facilitate the movement of the neck or more exactly the lower portion of the flange 16c of the resin bottle 16, and the notched ends 78a are followed by arcuate portions 78b having an internal diameter which substantially coincides with the external diameter of the neck (the lower part of the flange 16c) of the resin bottle 16. The two arms 78, the tension springs 82 and the pivot shafts 76 form together in combination grip means or gripper 50 which grips the resin bottle 16. A filling nozzle 52 is disposed above the resin bottle 16 which is gripped by the gripper 50, and during the time the resin bottle 16 which is gripped by the gripper 50 rotates together with the rotation of the revolving body 54, a filling valve, not shown, is opened to allow the filling nozzle 52 to fill the resin bottle 16 with liquid. The operation of the weight filler 6 constructed in the manner mentioned above will now be described. The resin bottle 16 which is conveyed on the feed conveyor 2 is gripped by a gripper 84 which is disposed toward the outer periphery of the introduction wheel 4. As shown in Fig. 2, the gripper 84 of the introduction wheel 4 grips the resin bottle 16 at a location which is disposed above the flange 16c formed on the neck of the bottle 16. As the introduction wheel 4 rotates to move the gripper 84 which holds the resin bottle 16 close to a hand-over position C (see Fig. 1) to the weight filler 6, the neck of the resin bottle 16 is gradually driven radially inward along the tapered surface 78a at the free ends of the both arms 78 of the gripper 50 on the weight filler 6. As the neck (or the lower part of the flange 16c) of the resin bottle 16 is driven inward along the tapered surfaces 78a, both of the arms 78 are gradually driven apart against the resilience of the tension springs 82 until the neck of the resin bottle 16 is fitted inside the arcuate portions 78b on the inner surfaces of the two arms 78, whereupon the both arms 78 are again urged toward each other by the tension springs 82, thus allowing the both arms to grip the neck of the resin bottle 16 from the opposite sides under the influence of such resilience. When the gripper 50 grips the neck of the resin bottle 16, the arcuate recess 72a formed in the front end face of the neck support plate 72 which is disposed above the gripper 50 abuts against the neck of the resin bottle 16 at a location above the flange 16c, thus supporting the resin bottle 16 in a stable manner. In the present embodiment, the gripper 50 of the weight filler 6 is designed to grip the underside of the flange 16c formed on the neck of the resin bottle 16 while the neck support plate 72 disposed above the gripper 50 is designed to abut and support the bottle at a location above the location which is gripped by the gripper 84 or the introduction wheel 4. As mentioned previously, the resin bottle 16 is driven into the gripper 50 to be gripped thereby in a direction which is substantially opposite from the direction in which the load applicator or rod 64 projects from the load cell 58, whereby a biased load or moment acting upon the load cell 58 can be reduced. In this manner, there is obtained the weight filler 6 which permits the neck carrying conveyance, and accordingly, the entire filling system which uses the weight filler 6 can be constructed with a conveying system which is based on the neck position of the resin bottle. In addition, in the weight filler 6, the load cell 58 which is installed to detect the vertical load is allowed to be flexed in the vertical direction while an urging load is applied to the horizontally projecting load applicator 64 in a direction which is opposite from the projecting direction. As a result of such arrangement, a flexure of the load cell 58 during the hand-over of the bottle can be prevented. If a flexure of the load cell 58 is allowed and the flexure is converted into oscillation as a result of reaction, a measurement of the weight will be influenced. However, with the arrangement of the present invention, a flexure of the load cell 58 during the hand-over of the resin bottle is prevented, advantageously avoiding the adverse influence upon the measurement of the filled weight. It will be appreciated that if the resin bottle 16 can not be successively handed over to the gripper 50 as a result of jamming during the hand-over of the resin bottle 16 from the introduction wheel 4 or to the intermediate wheel 8 to load the gripper 50 in the rotational direction, the neck of the resin bottle 16 may not be able to be received within the arcuate recess 72a formed in the front end face of the support plate 72 to cause a rotational load of an increased magnitude upon the support plate 72 also, but in the arrangement of the present invention, the shear pin 74 will break in response to a biased load in excess of a predetermined value applied to permit the support plate 72 to rotate, thus eliminating the likelihood of damaging the load cell 58. However, it should be understood that the rotation restricting means which restricts the rotation of the support plate 72 and the gripper 50 until a load in excess of a predetermined value is applied is not limited to the shear pin 74, but may comprise any other means known in the art. For example, a positioning recess may be formed in the lower surface of the gripper mounting block 68 while a ball which is urged by a spring to project above the upper surface of the neck support plate 72 may be provided for resilient engagement with the recess to define a ball plunger, thus restricting and releasing the rotation.

Claims: A weight filler (6) for filling a bottle (16) having a neck (16b), said neck having a flange (16c) spaced from the upper end of said neck; the weight filler (6) having a load cell (58) installed to detect a vertical load; the load cell having a load applicator (64) horizontally projecting from the load cell (58); grip means (50) supported by said load applicator (64) and serving, when the bottle is driven inward in a direction which is opposite from the direction in which the load applicator projects from the load cell, to resiliently grip the neck of the bottle below said flange; a filling nozzle (52) for filling the bottle when it is gripped by said grip means (50); the arrangement being such that a given amount of liquid is filled into the bottle which is gripped by said grip means (50) while detecting the load by means of the load cell (58); characterized by : a neck support plate (72) mounted on the load applicator (64) at a location vertically offset above the location of said grip means (50), there being an arcuate recess (72a) formed in a front end face of the neck support plate (72) and configured to abut the neck of the bottle above said flange (16c) to maintain the bottle in a stable manner whilst it is being filled. A weight filler according to claim 1 wherein; the grip means (50) is mounted on the load applicator (64) in a manner to be rotatable within a horizontal plane for resiliently gripping a neck (166) of a bottle; rotation restriction means (74) for maintaining the load applicator (64) and the grip means (50) in a given positional relationship to restrict a relative rotation therebetween and for releasing the restriction in response to a load applied which is in excess of a predetermined value; A weight filler according to Claim 2, characterized in that the rotation restricting means comprises a pin (74) which is connected between the load applicator (64) and the grip means (50) and which breaks in response to a rotational load which is in excess of a given value. A weight filler according to Claim 3, characterized in that a mounting block (68) is fixedly mounted on the load applicator (64) and carries said neck support plate (72) which is rotatable in a horizontal plane, the grip means (50) being mounted on the load applicator (64) through the neck support plate (72), the pin (74) connecting between the mounting block (68) and the neck support plate (72). A weight filler according to Claim 2, characterized in that the rotation restricting means (74) comprises a ball plunger including a positioning recess in one of the load applicator (64) and the grip meanst (50), and a ball mounted on the other of the load applicator and the grip means and urged by a spring to project for resilient engagement with the recess.

Inventors: NAKA TOSHIAKI, NAKADA TATSUHIRO, NISHINO YUKINOBU, NAKA, TOSHIAKI, NAKADA, TATSUHIRO, NISHINO, YUKINOBU
Applicants: SHIBUYA KOGYO CO LTD, SHIBUYA KOGYO CO., LTD
Application year: 2000
Main classification: B65B3
IPC codes: B65B3, B67C3