GB2099390A - A bag opening and emptying machine - Google Patents

Abstract

A bag opening and emptying machine comprises a drum contained within a housing 10 and rotatable about a horizontal axis and having a plurality of circumferentially spaced radial bag- receiving compartments 13, pairs of spikes (20) movable into the compartments to grip a bag received thereby during rotation of the drum, a knife 30 movable to slit each bag as it passes same during rotation of the drum, means 18 for vibrating the bags via isolated portions 15 of the compartment walls, to assist emptying of the bags, and cam and follower means (28, 27), to cause the spikes to penetrate the withdraw from the compartments at appropriate rotational positions of the drum. There is a hopper 50 for receiving material discharged from the bags, and a hopper 60 for receiving the emptied bags, the latter containing a bag compacting screw 61. <IMAGE>

Description

SPECIFICATION A bag opening and emptying machine This invention concerns a bag opening and emptying machine. Discharging the contents of large numbers of bags in rapid succession presents considerable problems because the bags are inherently difficult to handle, and often the contents are of a nature which will not readily flow.

It is an object of this invention to provide a machine which is capable of receiving bags in rapid succession, allowing the contents to be discharged and collecting the emptied bags, in a continuous operation.

According to the present invention a bag opening and emptying machine comprises a drum rotating about a horizontal axis and having a plurality of circumferentially-spaced radial bag-receiving compartments, means associated with each compartment to grip a bag received thereby, a knife movable to slit each bag as the bag passes same during rotation of the drum, whereby to allow the contents to be discharged, a hopper or duct facing the drum for receiving the discharged contents, means for vibrating the bags in the compartments to assist emptying of the bags, means for disengaging said bag gripping means thus to release the emptied bag to allow it to withdraw from its compartment into a bag receiving hopper or duct.

An embodiment of the invention will now be described, by way of example only, with reference to the accompanying schematic drawings in which: Figure 1 is a vertical section through the machine; Figure 2 is a more detailed view, on a larger scale, of a bag gripping and releasing mechanism; Figure 3 is a more detailed view of a part of the assembly shown in Figure 1.

Figure 4 is a diagram illustrating the rotational cycle of the machine in use, and Figure 5is a diagram showing how a bag is cut.

Referring now to the drawing, the bag opening and emptying machine comprises, within an outer casing 10, a drum rotatable about a central horizontal axis 11 and consisting of a plurality of substantially radial walls 12 defining four compartments 13 open at their outer ends. The ends of the drum are formed by a pair of discs 14, one of which can be seen in Figure 1. Each radial compartment wall 12 consists substantially of an isolated plate 15 which is mounted on the surrounding wall portion by rubber bushes 16 and sealing strip 17 of the kind illustrated in Figure 3, and the plates 15 are vibrated in operation by means of vibrator motors 18 mounted on cross members 19 to which adjacent plates 15 between compartments are attached.

Movable to project through appropriate apertures in the radial inner regions of the compartment walls 12 are pairs ofgripperspikes 20, and a mechanism to cause the spikes to enter and withdraw from the compartments at appropriate rotational positions of the drum, is illustrated in detail in Figure 2 and will now be described.

For each compartment 13, there are four pairs of gripper spikes 20 spaced along the length of the machine between the discs 14. Each pair is mounted on a pair of swinging arms 21 pivotally attached together at 22 and attached via a pair of articulated links 23 to one end of a rod 24 which is slidably engaged within a central drive shaft 25 rotating on the machine axis 11. The opposite end of each rod 24 carries a further pair of swinging arms 21 and a further pair of gripper spikes 20 in a similar manner for the diametrically opposite compartment.The articulated links 23 are pivotally attached to the rods 24 about an axis on which there are mounted a spindle 26 which extends along the machine parallel to the central drive shaft 25 and carries at its ends respectively a pair of wheels 27 which are located to run on the periphery of a pair of fixed non-circular cams 28 one at each end of the machine. It can be seen from Figure 2 that as each wheel 27 rides up the cam surface in a direction away from the axis 1 1,the associated rod 24 follows the spindle 26 and causes the articulated links 23 to draw the swinging arms 21 together thus causing the spikes 20 to enter the associated compartment 13.Simultaneously, the opposite end of the associated rod 24 is drawn towards the axis 11 and the associated pair of swinging arms 21 consequently are pushed apart thus causing the associated pair of gripper spikes 20 to be withdrawn from this compartment 13. In this way, the spikes 20 are caused to grip and release bags contained within the compartments at certain rotational positions of the drum as pre-determined by the shape of the cams 28. For convenience, the shafts 26 are retained within elongate slots in the end discs 14 of the drum.

A moving knife schematically illustrated at 30, preferably a rotary knife, is located adjacent the drum and is adapted to move inwards to slit a bag as it passes the knife during rotation of the drum.

In use, with the drum rotating in the direction of the arrow X, bags are delivered consecutively from a belt conveyor orthe like through an inlet opening 29 in the casing 10 such that one bag enters each compartment 13. This part of the cycle is indicated by the letter A in Figure 4. Subsequently, the compartment passes through a zone B wherein the associated gripper spikes 20 are moved inwardly to grip the bag. With further rotation of the drum, through a slitting zone C the compartment passes the knife 30 which travels across the machine to slit the bag as shown in Figure 5. The cut is made along a line 31 spaced inwardly from, but close to one side edge of the bag and penetrates the latter leaving a central uncut region 32 in the lower wall.

During rotation, the vibrator motors 18 are energised so that in zone D the contents of the bag are induced to empty into a collection hopper 50. The way in which the bag is cut causes the uncut end regions close to the edge of the bag adjacent the cut, to fold inwardly, which ensures that no pockets remain which can hold back material when the bag is emptied.

As the emptied bag proceeds into zone E the gripper spikes 20 are withdrawn and, assisted by the vibration from the motors 18, the bag falls from the compartment into bag receiving hopper 60 from which the bags are fed and compacted by a con veying screw 61.

Finally, as the vacant compartment passes through zone F, any residual material or dust remaining in the compartment is extracted via an outlet 70.

Claims (10)

1. A bag opening and emptying machine comprising a drum rotating about a horizontal axis and having a plurality of circumferentially-spaced radial bag-receiving compartments, means associated with each compartment to grip a bag received thereby, a knife movable to slit each bag as the bag passes same during rotation of the drum whereby to allow the contents to be discharged, a hopper or duct facing the drum for receiving the discharged contents, means for vibrating the bats in the compartments to assist emptying of the bags, and means for disengaging said bag gripping means thus to release the empty bag to allow it to fall from its compartment into a bag-receiving hopper or duct.

2. A bag opening and emptying machine according to Claim 1, wherein said bag gripping means comprises for each compartment, one or more spikes and means for causing same to penetrate the associated compartment after a bag has been received therein, said disengaging means causing said one or more spikes to be withdrawn from said compartment at an appropriate rotational position of the drum, thus to release an emptied bag.

3. A bag opening and emptying machine according to Claim 1 or Claim 2, wherein said knife is at a fixed disposition relative to rotation of the drum, but is movable to enter a compartment, slit a bag therein, and withdraw, this cycle of motion being adapted to take place at each occasion when a bag-containing compartment passes the position of the knife.

4. A bag opening and emptying machine according to any one of Claims 1 to 3, wherein at least a part of the walls of each compartment is vibrated during rotation of the drum thus to transmit the vibrations to the bags and their contents.

5. A bag opening and emptying machine according to Claim 4, wherein the vibrated part of each compartment wall is isolated from the remainder of the walls thereof, and is connected to a vibrating motor also connected to an isolated wall portion of an adjacent compartent.

6. A bag opening and emptying machine according to any preceding claim, wherein said means for disengaging said bag gripping means, comprises a fixed cam, and a plurality of cam followers connected by pivotted links to respective pairs of bag-gripping spikes, whereby movement of the cam followers causes the spikes to close together to grip the bag.

7. A bag opening and emptying machine according to any preceding claim, wherein said knife is a rotary knife and movable to slit each bag along a line spaced inwardly from but close to one wall of the bag leaving a central uncut region in said wall.

8. A bag opening and emptying machine according to any preceding claim, comprising, in said bag-receiving hopper or duct, a compacting and conveying screwfordischarging emptied bags.

9. A bag opening and emptying machine according to any preceding claim, including means for extracting dust from said compartments after the emptied bags are released therefrom.

10. A bag opening and emptying machine, substantially as hereinbefore described, with reference to and as illustrated in the accompanying drawings.