Abstract:
A bag closing apparatus including a frame structure, a cinching assembly and an actuator assembly. The cinching assembly includes at least three pivot arms, each pivot arm including an arcuate portion and pivotably connected to the frame structure. The pivot arms are located relative to each to define a confined closure area. The actuator assembly includes a plurality of actuators for moving the pivot arms between spread positions and closed positions wherein the closure area has a smaller area.

Description:
BACKGROUND 
     The present invention relates to the unloading of bulk bags used as containers for dry or moist particulate materials. The present invention more particularly relates to the unloading of bulk bag containers fabricated from cloth like material, such as woven polyester material, which is usually sewn in a cubical configuration. 
     Bulk bags made of heavy cloth material have been known in the art for sometime. It has also been known to provide the bag with heavy corner straps which support the bag when it is hung in a tower like support frame. The opposite end of the bag typically has a central outlet spout which is aligned with a discharge unit, for example a conveyer, hopper or the like, into which the material in the bag is intended to be discharged. Prior to discharge, the spout is maintained in a closed position, typically by tying-off of the spout. 
     To discharge the bag, the bag is hung in the support frame and the spout engaged with the discharge unit. The spout is opened and the particulate material flows via gravity through the spout. It is often desirable to control flow of material from the spout, for example, to permit batch weighing or to permit re-tying of the bag. Various types of bag closing devices, examples of which are illustrated in FIGS. 1-3, have been employed. In the device of FIG. 1, opposed bars, either flat or cylindrical, are moved together by fluid cylinders. As the spout is closed, it flattens in the direction of the arrows in FIG.  1 . As a result, the flattened, wide spout is difficult to re-tie, particular if the spout is short. The device of FIG. 2 attempts to overcome such by providing substantially v-shaped opposed bars, as described in U.S. Pat. No. 5,787,689. However, at the two points of overlap between the opposed bars, the bag is susceptible to pinching which may cut the bag or the bag may roll out between the overlapped bars. Referring to FIG. 3, a “claw” like device is shown. The bag is again susceptible to pinching in such a device. Additionally, in some applications, for example where the particulate material is dense, a significant amount of torque is required to closed the opposed claw members. 
     Accordingly, there is a need for an apparatus which assists in restricting a bag spout while reducing the likelihood of pinching of the spout. 
     SUMMARY 
     The present invention provides a bag closing apparatus including a frame structure, a cinching assembly and an actuator assembly. The cinching assembly includes at least three pivot arms, each pivot arm including an arcuate portion and pivotably connected to the frame structure. The pivot arms are located relative to each other such that each pivot arm crosses at least two other pivot arms to define a confined closure area. The actuator assembly includes a plurality of actuators for moving the pivot arms between spread positions wherein the closure area has a predetermined area and closed positions wherein the closure area has a smaller area. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING(S) 
     FIGS. 1-3 are top plan views of prior art bag closing devices. 
     FIG. 4 is a top plan view of the preferred embodiment of the present invention. 
     FIG. 5 is a cross-sectional view of the housing of the preferred embodiment of the present invention. 
     FIG. 6 is an exploded view of the housing of the preferred embodiment of the present invention. 
     FIG. 7 is a top plan view of a pivot arm assembly of the preferred embodiment of the present invention. 
     FIG. 8 is a side elevation view of a portion of the pivot arm assembly along the line  8 — 8  in FIG.  7 . 
     FIG. 9 is a cross-sectional view along the line  9 — 9  in FIG.  4 . 
     FIG. 10 is a cross-sectional view along the line  10 — 10  in FIG.  4 . 
     FIG. 11 is a cross-sectional view along the line  11 — 11  in FIG.  4 . 
     FIGS. 12-14 are top plan views illustrating the cinching sequence of the cinching assembly of the preferred embodiment of the present invention. 
     FIG. 15 is a flow diagram of the preferred operating system of the present invention. 
     FIG. 16 is a top plan view illustrating the cinching assembly with the pivot arms extended to a position beyond the central region, shown in FIG. 14, to an overlapped position. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The preferred embodiment of the present invention will be described with reference to the drawing figures where like numerals represent like elements throughout. 
     Referring to FIGS. 4-11, the preferred embodiment  10  of the present invention is shown. The bag closing apparatus  10  comprises a housing  20  and a cinching assembly  60 . Referring to FIGS. 5 and 6, the preferred housing  20  includes a split cylindrical body  30  secured between round top and bottom plates  24  and  40 . The plates have coaxial apertures  26  and  42  such that a cylindrical path  32  extends through the housing  20 . A plurality of mounting brackets  44  extend from the cylindrical body  30  for mounting the apparatus  10  on a frame (not shown) or other discharge unit (not shown). The body  30 , plates  24 ,  40  and brackets  44  are preferably manufactured from sheet metal of approximately 10 or 12 gauge. 
     A pair of cylinder mounting boxes  34  are secured to the housing  20  in alignment with the open areas  31  of the split housing body  30 . Each box  34  has a mounting plate  36  with an aperture  38  extending therethrough. As will be described in more detail hereinafter, a fluid cylinder  81  is mounted to each mounting plate  36  with its piston rod  82  aligned with the respective aperture  38 . The boxes  34  are preferably manufactured from 14 gauge sheet metal and the plates  36  from one-quarter inch (¼″) steel bar. The top and bottom plates  24 , 40 , the body  30 , the brackets  44 , the boxes  34 , and the mounting plates  36  are preferably welded together, but may be secured by other means. 
     A support ring  52  is preferably secured to the bottom plate  40  by a plurality of flanges  54  extending therefrom. The support ring  52  is preferably manufactured from a half inch (½″) steel rod and finished smooth on its upper surface. The support ring  52  provides support and a smooth guide surface for the pivot arms  72  as will be described in more detail hereinafter. A ring  28  depends from the top plate  24  about the aperture  26 . The ring  28  also provides a smooth guide surface for the pivot arms  72  as will be described in more detail hereinafter. 
     A removable support plate  48  with an aperture  50  therethrough may be attached to the top plate  24  with the apertures  50  and  26  coaxially aligned. The support plate aperture  50  is preferably sized to the dimension of the bag spout, i.e., if the spout has a sixteen inch (16″) diameter, the support plate aperture  50  will have a slightly oversized diameter. The support plate  48  thereby helps prevent sagging of the bag portion into the closing apparatus  10 . If a different size spout is used, the support plate  48  can be interchanged. An apertured guard  56  may be secured to the bottom plate  40  to help prevent unwanted objects from entering the apparatus  10 . The support plate  48  and the guard  56  are preferably manufactured from one-quarter inch (¼″) high density polyethylene. 
     The cinching assembly  60  will be described with reference to FIGS. 7-11. The preferred cinching assembly  60  comprises four pivot arm assemblies  70  and a pair of actuator assemblies  80 , although fewer or more of each may be utilized. Referring to FIGS. 7 and 8, each pivot arm assembly  70  includes a substantially J-shaped pivot arm  72  extending from a pivot tube  76 . The pivot arms  72  are preferably manufactured from half inch (½″) steel rod and may be provided with a tapered tip. A link tab  74  extends from each pivot arm  72  for interconnection with a respective actuator assembly  80 . Each pivot tube  76  includes a hollow body  77  upon which a respective pivot arm  72  is mounted. A shaft  78  extends through the hollow body  77  and is pivotably secured with respect to the top and bottom plates  24 ,  40 . Bushings  79  or the like may be utilized about the shaft  78 . 
     The preferred actuator assemblies  80  include fluid actuated cylinders  81  in communication with an air supply line or the like (not shown). A piston rod  82  extends from the cylinder  81  and is connected to an attachment plate  84 . A pair of link bars  88 , one above and one below, are pivotably connected to the attachment plate  84  via a pin  86  or the like. The opposite ends of the link bars  88  are then pivotably connected to a link tab  74  extending from a respective pivot arm  72 . By securing one link bar  88  above and one below the attachment plate  84 , the link bars  88  properly align with the link tabs  74  of the pivot arms  72  which are at different elevations. Alternatively, one actuator assembly  80  may be utilized for each pivot arm assembly  70 . 
     Referring to FIGS. 9-11, the four pivot arms  72   a - 72   d  are stacked one upon the other and upon the support ring  52 . The support ring  52  and top ring  28  are preferably spaced such that the pivot arms  72   a - 72   d  abut, as shown in FIG. 10, but remain slidable relative to one another. The abutting relationship helps prevent the spout from moving between adjacent pivot arms  72 . Referring to FIG. 11, the pivot arms  72   a - 72   d  are mounted at different heights on their respective pivot tubes  76  to provide proper alignment. Additionally, to provide proper alignment of the fluid actuated cylinders  81 , such are preferably mounted off-set from one another. As shown in FIG. 9, the higher mounted cylinder  81  actuates pivot arms  72   a  and  72   c  and the lower mounted air cylinder  81  actuates pivot arms  72   b  and  72   d.    
     The cinching sequence will now be described with reference to FIGS. 12-14. Referring to FIG. 12, the actuator assemblies  80  are non-energized and the pivot arms  72  are in an open, generally circular configuration. In this configuration, a spout can be passed through the assembly  10  and engaged with a discharge unit. When it is desired to close the spout, the fluid cylinders  81  are actuated to extend the rods  82 . The pivotably connected link bars  88  translate the linear force to move the pivotably connected pivot bars  72  along an arcuate path as represented by the arrows A in FIG.  13 . The arcuate path and the curvature of the pivot arms  72  minimizes the potential for pinching of the spout. Actuation of the cylinders  81  continues as the pivot arms  72  constrict the bag to a central region  90 . The pivot arms  72  are then extended to a position beyond the central region  90 , as shown in FIG. 16, and overlap such that the bag spout forms a “Z” as it travels between the pivot arms  72 . The over extension is preferred, but may not be required in all applications. 
     The preferred operating system  100  of the closing assembly  10  will be described with reference to FIG.  15 . The preferred operating system  100  includes a manual valve  102 , a safety push button  104 , a selector switch  106 , a timer  108 , and an automatic control  110 . The manual valve  102  controls the flow of fluid into the cylinders  81  and is moveable between a nuetral position and “close” and “open” positions wherein fluid is provided to the cylinders  81  to extend or retract the rods  82 . To operate the assembly  10  manually, an operator uses the manual valve  102  to control flow into and out of the cylinder  81  as desired. The system  100  also preferably includes a safety push button  104  which closes the fluid supply  101  unless engaged. If either the push button  104  or valve  102  is released, pressure to the cylinder  81  will cease. As such, the operator must use one hand to engage the push button  104  and the other to operate the manual valve  102 , thereby reducing the likelihood the operator will inadvertently place a hand in the path of the moving components. 
     In some instances, an operator may want to remove one or both hands while maintaining pressure in the cylinder  81 , for example, to retie the spout. As such, the preferred system  100  also includes an automatic control  110 . To utilize the automatic control  110 , the selector switch  106  must be in the “auto” position. If the switch  106  is in the “auto” position, the timer  108  will time the duration the manual valve  102  is in the “close” position. If the manual valve  102  is in the “close” position for a given time interval, for example five seconds, the timer  108  will trigger the automatic control  110 . The automatic control  110  will then continue to supply fluid pressure to the cylinder  81 , irrespective of whether the manual valve  102  or push button  104  are engaged, until the operator moves the selector switch  106  to a “manual” position. With the selector switch in the “manual” position, the operator can use the manual valve  102  to open the cinching assembly  60 . Other manual and automatic operating systems may also be used.