GB2138769A - Apparatus for opening and emptying bags - Google Patents

Abstract

A bag opening and emptying apparatus comprises a platform (81) having two hinged halves which can be pivoted from horizontal to inclined positions by means of piston and cylinder devices. A rotary cutting blade (80) is positioned above the platform (81) and can traverse the platform upon movement of the blade over the platform or movement of the platform below the blade to cut a bag into two halves. Retractable spikes extend through platform to hold the cut bag halves whilst the hinged platform halves are pivoted to their inclined positions thus allowing the bag contents to fall out under gravity. The spikes are then be retracted to allow the bag halves to be discharged and subsequently compacted. Bags can be fed to the apparatus manually or automatically. <IMAGE>

Description

SPECIFICATION Apparatus for opening bags The present invention relates to apparatus for opening bags.

Apparatus for opening bags is known. In one such apparatus bags are fed between a pair of driven spiked rollers onto a reciprocating knife. The bag is slit at its lower end and the bag drawn away from its contents by the rotation of the spiked rollers thus allowing the contents to fall away under gravity. The above described parts are enclosed in a housing.

This reduces the risk of injury from unintentional contact with the moving parts of the apparatus. It also reduces the risk that possibly unacceptable levels of injurious dust will be released into the atmosphere. This apparatus is efficient and works well in practice.

However, its speed of operation may not be required under some circumstances and its expense may not be justified.

According to the present invention, there is provided apparatus for removing the ccntents of bags comprising a support for the bags, means for retaining a bag on the support, means for cutting a bag supported on the support, means for producing relative movement between the bag and the support so as to produce a bag cutting action and means for moving the support from a position in which cutting can be achieved into a position in which the contents of the bag are allowed to fall therefrom under gravity. In one embodiment of the invention, the support comprises two hinged parts and the means for moving comprises respective hydraulic or pneumatic piston and cylinder devices. The means for cutting may be moved over a stationary support or the support may be moved under a stationary means for cutting.In the former case the means for cutting may comprise a blade mounted for transverse movement on racks. In the latter case support may be chain driven between the first and second positions by means of two endless chains disposed on opposite sides respectively of the support.

These chains are driven by respective sprockets on which they are themselves supported and the support is connected to the chains by brackets.

A wiper device may be provided for wiping a bag off the support after emptying. Means provided for retaining the bag on the support, which may comprise a plurality of spikes on which the bags are impaled, are withdrawn prior to wiping. The apparatus may be enclosed in a housing. Access to the housing may be via a hinged lid. This may be fitted with an interlock device operative to prevent operation of the apparatus whilst the hinged lid is open.

In order that the invention may be more clearly understood, two embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings in which: Figure 1 is an end elevational diagranmatic view of one end of apparatus for opening bags taken in direction X on Figure 3, Figure 2 is an end elevational diagrammatic view from the other end of the apparatus of Figure 1 in direction Y on Figure 3, but showing some hidden detail, Figure 3 is a side elevational diagrammatic view of the apparatus of Figures 1 and 2, Figure 4 is a detail diagrammatic view to an enlarged scale of a part of the apparatus of Figures 1 to 3, Figure 5 is a further detail diagrammatic view to an enlarged scale of another part of the apparatus of Figures 1 to 3, Figure 6 is a diagrammatic perspective view of a platform support for bags forming part of the apparatus of Figures 1 to 3, Figure 7 is a diagranmatic perspective view of the platform support of Figure 6 and of a bag wiper arrangement arranged above it, Figure 8 is a diagrammatic perspective view of the platform support of Figure 6, showing the platfform halves depressed, Figure 9 is a pneumatic circuit diagram for the apparatus of Figures 1 to 3, Figures 1 0A a B are electrical circuit diagrams of controls for the apparatus of Figures 1 to 3, Figure 11 is an electrical circuit diagram for the various electrical driving motors of the apparatus of Figures 1 to 3, Figure 1 2 is an end elevational view of another embodiment of the invention.

Figure 1 3 is a side elevational view of the apparatus of Figure 12, Figure 14 is a perspective view of a part of the embodiment of Figures 1 2 and 13, Figure 1 5 is a sectional view of a part of the embodiment of Figures 1 2 and 13, and Figure 16 is a perspective view of a further part of the embodiment of Figures 1 2 and 1 3.

Referring to Figure 1 to 3, the apparatus comprises a housing 1. Inside this housing 1 is disposed a bag support in the form of a platform indicated generally by reference 2.

This platform 2 comprises two halves 3 and 4 which come together along a line 5 extending longitudinally of the apparatus. Each half is rebated at its edge adjacent the line 5 to accomodate the lower edge of a cutting blade extending through a bag disposed on the platform. The halves 3 and 4 are respectively connected to two endless chains 6 and 7 which are mounted on and driven through respective pairs of sprockets 8 and 9 disposed on opposite sides respectively of the platform 2.

The chains 6 and 7 extend longitudinally of the housing 1 between a bag supply point, indicated generally by reference numeral 10, to a bag exit point, indicated generally by reference numeral 11. A chute 1 2 is disposed beneath the platform between these two points 10 and 11. Above the platform 2,between points 10 and 11, is disposed a rotary cutting blade 1 3 driven from an electric motor.A bag wiper arrangement is also disposed above the platform 2 downstream of the cutting blade 1 3. This wiper arrangement comprises two rubber wiper blades 14 and 1 5 mounted on a drive arrangement having two endless chains 1 6 and 1 7 mounted on respective sprockets 1 8 and 1 9 driven from an electric motor 1 9 though a transmission 20.

Each of the wiper blades 14 and 1 5 is split into two halves to enable passage thereof past the cutting blade 1 3 at the positions where they overlap (i.e. at the left end of the travel of the blades 14 and 1 5 viewed on Figure 3).

The respective halves 3 and 4 of the platform 2 are pivotally mounted on respective pairs 25, 26 of linear ball bush bearings.

These bearings 25, 26 are mounted for slidable movement on corresponding rails 27, 28 and are drivably connected to respective chains 6 and 7. The platform halves 3 and 4 may be pivoted from a subsidiary horizontal position to a depressed sloping position by means of respective pneumatically operable piston and cylinder devices 30 and 31 (see Figures 5 to 8).

Referring to Figure 4, each platform half incorporates means for retaining a bag half in position on the platorm. Each of these means comprises a series of spikes 35 mounted on a member 36 which may be moved by a pneumatic piston and cylinder device 37 from a first position in which the spikes are retracted below the level of the platform to a second position in which the spikes are extended above the upper surface level of the platform.

In this latter position a bag or bag half on the platform will be impaled by the spikes to prevent it slipping off the platform half when the platform half is in a depressed position.

The apparatus housing 1 incorporates a hinged lid 40 at the bag supply point 10 and a bag exit tunnel 41 at the bag exit point 11 in which the bags are compacted by a compactor driven by a motor 42. A safety interlock is fitted to the lid 40 to prevent operation of the apparatus when the lid is in the open position. A dust extraction unit 43 driven by a motor 44 is positioned above the wiper arrangement.

The operation of the apparatus will now be described with additional reference to the circuit diagrams of Figures 9, 1 or, 1 0B and 11.

After switching on the main isolator switch ISO the operator switches on the dust extraction unit 43 start pushbutton DFC and then switches on the machine start pushbutton MC. The lid 40 is opened opening contact LS1/1. A bag is loaded onto the platform 2.

This operates an infra red sensor which closes contact SR/1 (Figure 1).

The lid 40 is closed thereby closing LS1 /1.

The blade motor BM (Figure 11 )starts rotating the blade 1 3 in direction of arrow B, as contact, BC is energised. The platform 2 begins to move towards the blade 1 3 driven by motor PM when contact CPCF is energised. After the platform leaves the limit switch LS2, LS2/1 is closed which energises S1 which operate cylinders 37 which then force the spikes 35 into the bag on the platform 2,to hold the bag on the platform 2.

After the bag has been completely cut into two halves by blade 13, the platform 2 operates limit switch LS3 which opens LS3/1 stopping the platform. LS3/2 closes which energises S2 which in turn closes cylinders 30 and 31. This operates the hinged platform halves 3 and 4 downwards allowing material in cut bag halves to discharge into the chute 1 2 whilst the bag halves themselves on them are retained by the spikes 35. The length of time for discharge is controlled by variable timer TR 1.

When the present discharge time has lapsed the solenoid S2 is de-energised slowly closing the hinged platform 2, The time for closing is controlled by flow regulator FR1 and timer TR2. After TR2 time has elapsed TR2/1 opens de-energising S1 which retracts the spikes 35 from the bag halves. Wiper motor contactor WC is energised starting up the wipers in the direction of arrow W which push off the bag into the compactor 41/42.

Limit switch LS4 is operated by the wiper which stops wiper motor WM. As wiper is working timer TR3 begins time delay, at the end of TR3 time CPCR is energised starting up the platform 2 in the reverse direction.

When the platform 2 reaches the loading position 10 again LS2 is operated and stops the platform. The platform remains in this position until the next bag is loaded. When a bag is loaded sequence is repeated.

Figures 12 to 1 5 illustrate an embodiment in which, in contrast to the embodiment already described, a cutting blade 80 traverses a fixed platform 81 supported on a frame 82.

The platfform 81 is similar to platform 2 of the Figure 1 embodiment in that it comprises two halves 83 and 84 which may be pivoted between horizontal and depressed sloping positions by means of pneumatically operable piston and cylinder devices 85 and 86. Platform 81 also comprises rollers 87 to facilitate feeding of a bag to be slit onto the platform.

An infeed conveyor 90 leads into the platform 81 for the automatic feeding of bags to be slit. The apparatus may, however, also be used manually in which case bags would be supplied through a flap in the side of the apparatus and the infeed conveyor 90 dis pensed with. Manual direction of feed onto the platform 81 is shown by arrow 91 and automatic direction of feed by arrow 92 on Figure 14. The traversing mechanism for the cutting blade 80 is shown in Figure 16. This comprises a shaft 95, on which the blade 80 is mounted, which has two cogs 96 and 97 at opposite axial ends which engage respective tooth racks 98 and 99. A three-phase electric motor 100 drives the blade 80 and, through reduction gearing 101, the shaft 95 and cogs 96 and 97. This causes the blade to traverse as it rotates.At the end of its traverse the rotation of the motor is reversed by reversing two phases of the three phase supply. This causes the rotation of the blade to reverse and also the direction of travel.

In contrast to the arrangement of Figure 1, the fixed platform 81 is disposed directty above a compactor 110 comprising a screw 111 driven by a motor 112. Instead of the platform halves 82 and 83 being returned to the horizontal position with the platform spikes 89 still extended, the spikes are retracted whilst the platform halves are depressed to allow the bag halves to fall after the bag contents have already fallen past the screw 111. To encourage the contents and bag halves to fall, vibrators 11 3 (see Figure 15) are fixed to the underside of the platform.

This dispenses with the requirement for the bag wiper arrangement of the embodiment of Figure 1. The circuitry described with reference to Figures 10A, 10B and 11 would be modified to provide for the modifications in equipment and operation just described.

In automatic operation of the embodiment of Figures 12 to 16, the operator loads the bag onto the powered infeed conveyor 90 which conveys the bag onto the bag support platform 81. The bag is then spiked and is automatically cut completely in half by blade 80.

The bag support platform 81 then divides into its two separate halves 83 and 84 in a downwards motion allowing the material to automatically discharge from the bag into the material outlet chute. This gravity discharge is assisted by solenoid operated pneumatic vibrators 11 3. During the timed sequence the spikes retract ejecting the empty bag halves into the automatic waste bag compacting unit, which compacts the bag into a plastic receiving bag. During the bag ejection sequence the bag support platform returns to its horizontal position signalling the conveyor to feed in the next bag.

The integral dust extraction unit maintains a slight negative pressure in the machine during the bag opening operation. Manual operation is as described above except that a bag is placed by the operator on the platform 81 through the flap instead of being fed by the infeed conveyor. If the flap is opened during operation the machine will shut down.

It will be appreciated that the above embodinents have been described by way of example only and that many variations are possible without departing from the scope of the invention. For example, bags could be cut from underneath as well as from on top.

Claims (18)

1. Apparatus for removing the contents of bags comprising a support for the bags, means for retaining a bag on the support, means for cutting a bag supported on the support, means for producing relative movement between the bag and the support so as to produce a bag cutting action and means for moving the support from a position in which cutting can be achieved into a position in which the contents of the bag are allowed to fall there-ffrom under gravity.

2. Apparatus as claimed in claim 2, in which the support comprises two hinged parts.

3. Apparatus as claimed in claim 2, in which the means for moving comprises one or more pressure fluid operable piston and cylinder devices operative to pivot the hinged parts.

4. Apparatus as claimed in claim 3, in which the devices are pneumatic.

5. Apparatus as claimed in claim 3, in which the devices are hydraulic.

6. Apparatus as claimed in any preceding claim, in which the support is connected to a stationary frame and the means for cutting is movable relative to the support to produce the relative movement between support and means for cutting.

7. Apparatus as claimed in any of claims 1 to 5, in which the means for cutting are connected to a fixed member and the member is movable relative to the support to produce relative movement between support and means for cutting.

8. Apparatus as claimed in claim 6, in which the means for cutting comprise a blade mounted on a rack along which the blade can traverse.

9. Apparatus as claimed in claim 8, in which the means for cutting comprises a rotary blade on a shaft mounted through opposite axial ends of the shaft on respective racks.

10. Apparatus as claimed in Claim 8 or 9, in which an electric motor is provided for driving the blade and, through gearing, effecting traverse of the blade.

11. Apparatus as claimed in claim 7, in which the support is reciprocated by means of two endless chains disposed on opposite sides respectively of the support.

1 2. Apparatus as claimed in any preceding claim, in which the means for retaining the bag on the support comprises one or more spikes.

1 3. Apparatus as claimed in Claim 12, in which means are provided for extending and retracting the spikes from and back to the support.

14. Apparatus as claimed in any preceding claim, in which a compactor is provided for compacting empty bags.

1 5. Apparatus as claimed in claim 14, when appendant to any of claims 1 to 6, in which the compactor is disposed directly beneath the support.

1 6. Apparatus as claimed in claim 14 or 15, in which the compactor comprises a screw.

1 7. Apparatus as claimed in any preceding claim, in which control circuitry is provided operative to control the means for retaining means for cutting, the means for producing relative movement and means for moving the support in accordance with an interelated programme.

18. Apparatus for removing the contents of bags substantially as hereinbefore described with reference to Figures 1 to 11 or to Figures 12 to 16 of the accompanying drawings.