EP1838582B1

EP1838582B1 - Apparatus for automatically emptying bags

Info

Publication number: EP1838582B1
Application number: EP05747588.1A
Authority: EP
Inventors: Benjamin Cohen
Original assignee: Ayal Robotics and Engineering Ltd
Current assignee: Ayal Robotics and Engineering Ltd
Priority date: 2004-10-19
Filing date: 2005-06-07
Publication date: 2015-01-07
Anticipated expiration: 2025-06-07
Also published as: IL164709A; PT1838582E; EP2604537A1; SI1838582T1; EP1838582A1; WO2006043261A1; DK1838582T3; GB0517601D0; IL164709A0; HUE025153T2; ES2533003T3; PL1838582T3

Description

TECHNICAL FIELD OF THE INVENTION

The present invention relates to an apparatus for emptying bags according to the preamble of claim 1 and as known from DE 86 33 746 U .

BACKGROUND OF THE INVENTION

In most of the industries in fields such as polymers, pharmaceuticals, food, and chemistry, raw material is delivered in medium to large sized bags. Typically, the bags are arranged on pallets. Typically, discharging the bags' content is achieved by manual unloading and slitting the bags employing a knife and transferring the material to a receiver such as a funnel. Since the bags are relatively heavy, emptying the material into the processing machine by the worker that lifts the bags one after the other constitute a "bottle neck" in the progress of the processing. Moreover, raw material, which can be very expensive, is being lost throughout the process of emptying the bags into a receiver since a worker has to carry the sliced bag and shake it over above an opening of a receiver or a funnel.
Common automatic machinery such as a bags' splitter and a bag splitter and shredder have inherent drawbacks. A splitter system does not avoid the need for manual emptying which is costly both in labor and in the loss of material. In common splitting and shredding systems a bag full of raw material is inserted into the machine that shreds the bag so as to allow all the raw material to be dispensed into the processing apparatus. Due to the form of shredding, small pieces of shredded bag may enter the processing apparatus along with the raw material. Moreover, the process does not eliminate the need of the worker that places the bags in the machine. Therefore an apparatus that will quickly, mechanically slit the bags and empty them into a receiver of the processing apparatus is beneficial.
In DE 8633746 U1 a system for emptying bags is disclosed which features, among other properties, a spike bearing system with either one or two spikes deployable for the purpose of gripping bags of a product. The gripping facilitates the carrying of the bags and subjecting them to slitting. The present invention features several improvements over this system.

SUMMARY OF THE INVENTION

In accordance with the present invention, an apparatus for emptying stacked bags according to claim 1 is provided. The apparatus has a gripper having a plurality of pointed gripping elements and a slitting and emptying device. The gripper is capable of gripping one or more bags ordered or heaped in disorder. The gripping elements are arranged in two arrays such that a bag is gripped by a number of gripping elements disregarding the bags' arrangement in a layer. Gripping is accomplished by forcing a number of pointed gripping elements into one or more bags. The gripper is incorporated in a gripping unit, which also lifts the gripped bags and carries them to the bag slitting and emptying device. The bag slitting and emptying device simultaneously slits and empties the bags by means of a plurality of blades aligned with rods. A cyclic displacement of either the rods relative to the slitted bags, or the slitted bags relative to the rods, discharges leftovers of the contents of the bags.

BRIEF DESCRIPTION OF THE FIGURES

Fig. 1: is a schematic description of the main subsystems of an apparatus for emptying bags wherein the gripping unit is loaded;
Fig. 2A: is a schematic description of an array of gripping elements pivotally connected to a suspension shaft;
Fig. 2B: is a schematic description of an array of gripping elements pivotally connected to a suspension shaft in an extended position;
Fig. 2C: is a description of another array of gripping elements pivotally connected to a suspension shaft inan extended position;
Fig. 3A: is a front side view of a section of a gripper having its PGEs retracted;
Fig. 3B: is a front side view of a section of the same gripper shown in Fig. 2A, with extended PGEs;
Fig. 3C: is a bottom view of a section of a gripper according to another embodiment;
Fig. 4: is a frontal view of a section of an apparatus for emptying bags, before starting a step of slitting bags, according to another embodiment.
Fig. 5: is an isometric view of a section of a slitting and emptying device according to a preferred embodiment of the present invention;
Fig. 6: is an isometric view of a section of an apparatus for slitting and emptying bags in accordance with another embodiment;
Fig. 7: is an isometric view of an apparatus for emptying bags ;
Fig. 8: is a side view of the apparatus for emptying bags implementing debris compression;
Fig. 9: is an isometric view of a section of an apparatus for emptying bags, in which a lift is incorporated according to another embodiment.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides a novel apparatus for emptying bags as for example to discharge a raw material into a receiver of a processing system. The apparatus of the present invention simultaneously grips and lifts a plurality of bags from an upper layer of stacked bags; slits the bags and discharges their contents. The apparatus of the invention is an assembly of several subsystems, each performing a certain task in the overall process.
Reference is first made to Fig. 1, which describes schematically the main structural units of an apparatus for emptying bags of the invention and the functional relationships between them. In Fig. 1 gripping unit 12 picks up one or more bags 14 from stack 16. The bags are brought to the emptying unit 18 for slitting and emptying. When emptying has finished, the gripping unit 12 disposes of the debris of the empty bags 14. The griping unit 12 resumes its position at stack 16 and picks again one or more bags. The function of the gripping subsystem is therefore repetitive, moving cyclically between two extreme positions.

The gripping unit

This unit includes a gripper, an actuator and an extendible arm. The role of the actuator is to move the gripping unit between the two extreme positions as described above. The gripper according to the invention employs pointed gripping elements (PGEs) such as hooks or stakes. One end of each gripping element is connected to an axis whereas the tipped end is free. The PGEs are grouped in two arrays in each of which each of the PGEs point in the same direction. The PGEs of both arrays are movable between two extreme positions respectively. The extreme positions are a fully extended position and a fully retracted position. All the PGEs of an array move in the same direction when changing from one extreme position to the other. Conversely, PGEs of different arrays move in different directions from one extreme position to the other. Reference is now made to Figs. 2A - 2C in which PGEs of both arrays are schematically described. As can be seen in Figs. 2A -2C , exemplary two PGEs of an array 40 are pivotally attached to a PGE suspension shaft 42. PGEs 44 and 46 are inclined towards shaft 42. In an extended positioning, PGE 44 is designated 44A, and PGE 46 as PGE 46A, in which position the free pointed tips are pointing substantially away from shaft 42, more towards the bottom. The retracting - extending action is forced by one or more actuators (not shown) which actuate forcing shaft 48 to position 48A. To draw the PGEs, the forcing shaft 48 is moved in the direction of arrow 56. As shown in Fig. 2B , the two exemplary PGEs are fully extended, designated here as PGE 44A and PGE 46A. Forcing shaft 48A is in a PGE drawing position. These PGEs are generally rotatable around pivots 52 but may be locked in a specific position. In Fig. 2C a portion of the other array of PGEs is shown extended, wherein all PGEs are pointing in an opposite direction that the PGEs in Fig. 2B point. Moving these PGEs to the fully extended position is similarly effected by moving forcing shaft 49B in the direction of arrow 50B.
For gripping, the extendable arm lowers the gripper to the upper layer of bags. Then, the PGEs are retracted, forcing their tipped ends into the accessible bags. PGEs of one array are extended in one direction whereas the PGEs of the other array are extended in an opposing direction as described above. The spacing between the individual PGEs of an array and the spacing between two adjacent PGEs of different arrays are typically changeable and are a matter of consideration of the bags, size and order. Typically it is required that the bags when gripped and lifted should not be torn by their own weight. The number of PGEs pointing in one direction of an array does not necessarily equal to the number of PGEs pointing oppositely of the other array.
Reference is now made to Figs 3A and 3B in which a frontal view of a section of a gripper is shown. In Fig. 3A PGEs are shown in a fully extended position. Gripper 60 includes a plurality of rotatable PGEs. As described above PGEs of two different arrays are rotatable between two positions. PGEs 62 belong to one array and PGEs 63 belong to the other array. PGEs 62 are pivotally attached to suspension shaft 64 by means of axles 65 whereas PGEs 63 are attached by means of axles 65A. PGEs of both arrays are moved into a fully retracted position by counterclockwise rotating PGEs 62 and rotating PGEs 63 clockwise. Rotating all PGEs in the opposite directions brings them back to the fully retracted position. These rotations are effected by means of a pneumatic actuator 66 and connecting shafts. Typically, PGEs of one array are interleaved with PGEs of the other array. PGEs of each array are arranged in rows according to this preferred embodiment of the invention wherein rows of different arrays are interleaved.
As shown in Fig. 3B the PGEs of both arrays are fully retracted and PGEs of both arrays are in the fully retracted position such that tipped ends of PGEs of different arrays such as 62B and 63B, point one towards the other The pneumatic actuator 66 is attached to a frame of the gripper perpendicular to the rows of PGEs of both arrays. Typically the rows of PGEs are arranged in pairs such that one pair member is of different array than the other pair member. Thus PGE 62B is the extreme PGE in a row perpendicular to the plane of the drawing and PGE 63B is the extreme PGE in another row perpendicular to the plane of the drawing. All PGEs of a row have a common axis of rotation. A gear set, not shown, attached to each PGEs' axel, rotationally connects two adjacent PGEs, one of each row in a pair of rows. Therefore when all the PGEs of row 62B are rotated clockwise, by moving shaft 66A, PGEs of row 63B are rotated in the opposite direction. The forceful retracting of the PGEs punches the bags accessed by the PGEs, forcing the PGEs into those bags.
A proper selection of spacing between the PGEs in a row as well as the spacing between the rows can insure that each of the bags in the upper layer of stacked bags is gripped by a number of PGEs of both arrays. A bag is characterized by a certain length, width and depth. The depth is typically significantly smaller than its width, which is smaller than its length. For example, the spacing between two adjacent pairs of rows of different arrays is such that the distance between the tipped ends of adjacent PGEs of different rows when PGEs are fully retracted, is smaller than the typical depth of a bag; the spacing between two adjacent pairs of the same rows is smaller than a typical length of a bag; and the spacing between two adjacent PGEs in a row is smaller than a typical width of a bag. Such a gripper is capable of gripping bags of an upper layer arranged in any direction relative to its lower face. Furthermore a layer of bags need not be leveled in order to be gripped and lifted. However when the bags are laid out in disorder, only a portion of the number of bags in the top layer may be gripped at a time.
The tipped end section of the PGE moves along a circular path as it extends/retracts. The tip section is arcuate conforming with their rotation along a circular path. Therefore the hole punched in a bag by a PGE, is kept to a minimal size and the bags are not torn excessively by the rotating PGEs. This allows for a minimal loss in contents along the path from the stack to the emptying position. The shafts 64 to which the PGEs are attached are optionally suspended from a weighing device, not shown, which is connected to frame 68 of the gripper. To accomplish weighing, a load cell or preferably four load cells are employed. The measured weights are optionally further reported to a computer system carrying out tasks of process control and or material and stock management.
Optionally, gripper 60 when located above the stacked bags, finely adjusts its positioning above the stack of bags to conform with the position of the upper layer of the stack, to be able to grip as much of the layer as possible. To manage such fine positioning above the layers, at least one sensor 70 is employed. Other grasping mechanisms may also be employed instead of, or in addition to, the PGEs of the gripper as described herein above. Such are for example vacuum nipples mounted on the bottom of the gripper's frame.
Reference is now made to Fig. 3C in which a bottom side view of a section of a gripper according to another embodiment is shown. The PGEs are pegs such as 72, 74 and 76. All PGEs point in a general downward direction. However PGEs of different arrays are tilted aside in opposite directions. PGEs 72 which belong to one array of PGEs are attached to a horizontal shaft 78 forming a row whereas PGEs 74 which belong to the other array are attached to shaft 80 forming another row of PGEs. PGEs 76 which are attached to shaft 82 belong to same array as PGEs 72 as they point in the same direction. The numbers of PGEs of both arrays need not be equal and the number of rows need not be even. The PGEs of both arrays are shown in a fully retracted position. Shafts 78, 80 and 82 are linearly movable along the directions shown by the double arrows 84 and 86 correspondingly, between the fully extended and fully retracted positions. For gripping stacked bags the gripper having its PGEs extended is placed on top of an upper layer of bags. At this stage all PGEs are forced into the fully retracted position by moving shafts such as 76, 78 and 80, in a general downward direction along the arrows 84 and 86 as shown in Fig. 3C . The upper surfaces of bags of the upper layer are punched by the tipped ends of the PGEs being forced into the bags while moving to a fully retracted position.
Five parameters define a configuration of a gripper according to this embodiment. The parameters are i. the tilting angles of the PGEs; ii. the number of PGEs in a row; iii. the spacing between PGEs in a row; iv. the spacing between adjacent rows in which its PGEs are tilted towards each other such as rows of PGEs 72 and 74, and v. the spacing between rows in which its PGEs are tilted away from each other such as rows of PGEs 74 and 76. These parameters are determined with reference to the dimensions of a layer of bags and the dimensions of an individual bag, such that a bag is gripped by a number of PGEs of at least two different rows.

Slitting and emptying device

After having gripped the available bags, gripping unit moves loaded towards the slitting and emptying device. Reference is now made to Fig. 4 illustrating a frontal view of a section of an apparatus for emptying bags while cutting the gripped bags. Gripping unit 90 advances in a path along a rail, not shown, located on top of the upper frame 92 towards the rotating blades 94. The main frame 96 of the gripper is attached to the extendible arm 98 located at the bottom of the gripping unit 90. The curved PGEs 100 which are at a fully retracted position hold bags 102 of which only three are shown. Rods 104, which are aligned with the rotating blades 94 penetrate the slits in the bags and help disrupt the bags and separate between suspended stripes of the slitted wrapping of the bags as they advance. The bags' contents fall down into receiver 106, positioned beneath the rods and blades.
Reference is now made to Fig. 5 in which an isometric view of a section of a slitting and emptying device is shown. Rods 160 are disposed in parallel and aligned continuous with the rotary blades 162. Rotary blades 162 having a common drive axis 163, actuated by a motor 164. A portion of the debris of the bags, which are suspended pieces of cut bags, not shown, are forced by the weight of some of the bags' content and therefore are curved downwards into spaces between any two adjacent rods. Rods 160 are leveled at such a height above the axis around which the blades rotate, that a considerable portion of these downwardly curved debris of bags reach down substantially below the rods. A horizontal displacement of the upper faces of the gripped bags in both perpendicular directions to rods 160 pulls aside and tilts these debris of bags accordingly. Shaking the gripper aside in both perpendicular directions to the rods 160 when it has passed the rotary blades and reaches a predetermined location above the receiver 166 discharges leftover material born by these suspended debris of bags.
An alternative approach of discharging the leftover material withheld in the debris of the bags is described with reference to Fig. 6 in which an isometric view of a section of a slitting and emptying device in accordance with a preferred embodiment of the present invention is shown. Slitting and emptying device 180 consists of horizontally displaceable rods. Rods 182 are attached to a frame 184, which is off centered connected to a wheel 186 driven by a motor 188, by means of a shaft 190. Another motor 192 drives the rotating blades 194 which are disposed in front of the rods 182. The rotating wheel 186 moves the rods 182 in a cyclic horizontal translation in directions shown by an arrow indicated by 1196. The rods 182 are leveled above the axis of rotation of the rotary blades at a height, which is selected in a similar manner as, described herein above. Suspended debris of bags, not shown, which are engaged by two adjacent translating rods are tilted in opposing directions. Therefore by vigorously shaking either the gripper, or the rods, the remains of the bags' contents withheld by the debris of bags are discharged.

Example 1

Reference is now made to Fig. 7 in which an isometric view of an automatic apparatus for emptying bags in accordance with another embodiment is shown. The apparatus includes a deck 190 at its frontal bottom portion. Deck 190 is adapted to receive a plurality of bags 192 that are preferably organized in several layers disposed over a palette. The bags are delivered and loaded onto the deck typically by a forklift truck, not shown. Deck 190 is optionally provided with a waste container 194 adapted to receive bags debris.
The apparatus includes a gripping unit 196 movable back and forth along rails 198 from a first side of an upper frame 200 located above the bags to the opposite side. Gripping unit 196 grips bags 240, lifts them from deck 190, deliver them to a slitting and emptying device 202 in which they are slitted and emptied. Gripping unit 196 disposes of the empty bags by dropping them into the waste container 212. Gripping unit 196 operates an actuation means 204 adapted to translate the gripping unit along rails 198. Extendible arm 206 adjusts the height of the gripper 208 located at the bottom of the gripping unit 196. As shown in Fig. 7 the loaded gripping unit 196 is in a halfway position on its way towards the slitting and emptying device 202.
After emptying the bags by means of the slitting and emptying device 202, the gripping unit moves back and parks in a predetermined location above the waste container 212. Consequently the PGEs are fully extended and the released bags debris are dropped down. To minimize the volume of the debris, a scheduled additional step in which the heap of debris is compressed, is implemented in the cyclic process. Reference is made to Fig. 8 showing a side view of the apparatus described hereinabove, at a step in which debris of bags are compressed. Gripping unit 210 reaches a certain location above the opening of container 212 while it is still loaded with full bags 240 on its way towards the slitting and emptying device 214. Then gripping unit 210 stops, arm 215 extends down into the container 212 and the weight of the current gripped layer of bags compresses the heap of bags debris, not shown, residing in the container. Alternatively the waste container can be placed adjacent to slitting and emptying device 202 at the side opposing bags 240. In such a case the bags' debris are released off gripper 208 immediately following their being emptied. The bags' debris released at the end of one emptying cycle are further pushed off slitting and emptying device 202 and fall into the waste container during the following emptying cycle. Pushing off is accomplished by means of a grate, not shown, attached to gripper 208 at the side facing slitting and emptying device 202.
Legs 217 that are firmly secured to the floor support base construction 216. However, wheels 218 are provided so as to allow displacing the apparatus from one place to another or for maintenance purposes. Optionally, a funnel 219 is provided beneath receiver 220 through which bags' content is further delivered to a processing machine, a storage tank, or the like.
Control unit 222 activates and controls the operation and cooperation of the gripping unit and the slitting unit as well as the operation of the entire system. Controller 222 is preferably provided with a display 224 over which data, messages and instructions to an operator are displayed. Functional keys 226 by which operational data and instructions are inputted by an operator are preferably located on the front panel of the controller 222. Optional wired or a wireless communication link to a background plant computer system is incorporated in the controller 222. Instructions and messages are downloaded from the plant computer system through this communication link such as the identities of materials to be discharged by the system, its quantities, locations and destinations. These data and messages are further displayed to the operator. Records such as of time tagged operational data originated by the operator, system statuses and weights of the discharged materials are uploaded through same communication link from controller 222 to the plant computer system.

Example 2

Reference is made to Fig. 9 in which a frontal view of a section of an apparatus for emptying bags having a lift for elevating the bags according to another embodiment is shown. A lift 230 is installed in a front side of the deck 232 of the apparatus of the invention. Typically elevating the lift is hydraulically activated. In some embodiments the lift is activated mechanically such as by means of an electric motor. The lift is secured to the floor and or is optionally attached to the base frame 234, not shown. Palette 236 is placed on top of the lift on which bags 240 are stacked. The lift repeatedly elevates the residual layered bags by a predetermined height during the time in which the gripping unit 242 has left its first position above the layered bags and prior to its returning back to the same location. Therefore the distance in which the gripper has to be lowered towards the current upper layer in order to grip it is significantly shortened which in turn promotes the processing speed of the entire system.

Claims

An apparatus for emptying bags, comprising a gripping unit (12) for picking up bags, and a bag slitting and emptying device (180) to which the bags are brought by the gripping unit (12) and at which the bags (18) are emptied, characterized in that
• said gripping unit (12) comprises a gripper (60) having a plurality of pointed gripping elements (44, 46, 62, 63, 72, 74, 76) arranged in at least two arrays (62, 63; 62B, 63B; 72, 74), such that the pointed gripping elements of one array point in the opposite direction to the other array, for gripping at least one of said bags, said pointed gripping elements having a first end connected to said gripper and a second tipped free end, and being moveable between a first position in which said pointed gripping elements are retracted and
a second position in which said pointed gripping elements are extended, and

• the bag slitting and emptying device (180), comprises:
∘ at least two parallel rotary blades (194) for slitting said at least one bag,and

∘ at least two rods (182) aligned in a row respectively with said rotary blades, being shakeable relative to said at least one slitted bag.
An apparatus for emptying bags as in claim 1, further comprising an upper frame (200) having a first end and a second end, wherein said gripper is moveable in a path along said upper frame from said first end to said second end,
and vice versa, and wherein said gripper is capable of stopping above a waste container (212) adaptable to receive bags debris.
An apparatus for emptying bags as in claim 2, further comprising a grate for pushing debris off said slitting and emptying device.