GB2301056A - Compressing apparatus - Google Patents

Abstract

Apparatus (1) for compressing empty containers comprises a cabinet (2), a door (4) pivotally mounted on the cabinet, compression means (8, 9) for effecting compression of a container positioned in the cabinet, and a control system for controlling operation of the compression means. The pivotal mounting of the door (4) incorporates a cam (12) the which operates switching means (15) such that closure of the door permits operation of the compression means (8, 9) and opening of the door prevents such operation. The switching means (15) is provided in a housing (11) on the top of cabinet (2) so that the door must be closed before the compression means can effect a working cycle. Residue from the container passes through grid (5) to a recepticle (7).

Description

APPARATUS FOR COMPRESSING CONTAINERS The present invention relates to an apparatus for compressing empty containers (particularly but not exclusively metal containers) to reduce the volume thereof.

Certain industries use large amounts of products supplied in metal containers (e.g. 30 litre drums). The empty containers are then either disposed of or sent for recycling for their metal content. However the storage of large numbers of empty containers (prior to disposal or recycling) obviously poses a problem in view of the overall volume of the empty containers.

In order to overcome this problem, the empty containers may be compressed (e.g. along their longitudinal axis) so as to flatten the container and reduce its volume (e.g. by 85%). Apparatus for effecting such compression generally comprises a cabinet in which the container may be placed and means for effecting compression of the container. These means may comprise a fluid actuated cylinder which is operatively associated with a crusher plate which acts on the container to effect compression thereof.

In view of the forces exerted by the compression means, it is obviously necessary to have a safety arrangement to ensure that personnel do not insert their hands, arms or other limbs into the cabinet during a compression operation. To this end, the cabinet of known compression apparatus generally comprises a door associated with a safety switch actuated when the door is closed to allow operation of the compression means. When the door is opened, the switch is moved at a position at which the compression means is non operative.

The known apparatus does however suffer from the disadvantage that the safety switch associated with the door is operated by an inner face of the door coming into engagement with the switch. As such, the switch is readily accessible and can be actuated relatively easily by personnel when the door is open to allow the compression means to be operated. Thus in order to save time it is known for personnel to keep the cabinet door open and simply to actuate the safety switch to effect a compression operation. This is obviously dangerous since personnel may inadvertently insert, say, their hands in the cabinet during a compression operation.

The hand may then be crushed.

It is therefore an object of the present invention to obviate or mitigate the abovementioned disadvantages.

According to the present invention there is provided apparatus for compressing empty containers comprising a cabinet, a door pivotally mounted on the cabinet compression means for effecting compression of a container positioned in the cabinet, and a control system for controlling operation of the compression means wherein the pivotal mounting of the door incorporates a cam which is rotated by opening and closing of the door and the control system incorporates switching means operatively associated with the cam such that closure of the door permits operation of the compression means and opening of the door prevents such operation.

The provision of the switching means so as to be operable by a cam associated with the hinge arrangement allows the switching means to be mounted in a position which is inaccessible to an operator of the apparatus.

For preference the cam and switching means are positioned in a housing on the cabinet.

Preferably the cam is provided on a spindle which is rotationally fast with the door and is coaxial with the pivotal mounting thereof The spindle may provide part of the pivotal mounting of the door.

The control system is preferably such that, upon closure of the door, the compression means automatically effects a working cycle of strokes so as firstly to compress a container within the cabinet and then return to its original position.

The compression means preferably comprises a fluid actuated cylinder and the switching means is a fluid control valve. The cylinder may be pneumatically operated and the control system comprise an arrangement of an air switching valve.

The invention will be further described by way of example only with reference to the accompanying drawings, in which: Fig. 1 illustrates one embodiment of can crushing apparatus in accordance with the invention; and Fig. 2 illustrates a pneumatic control circuit arrangement used in the apparatus of Fig. 1.

Referring to Fig. 1 the illustrated can crushing apparatus 1 comprises a cabinet 2 supported on four legs 3. The cabinet 2 is provided with a front door 4 and has a base in the form of a grid 5. Below the grid 5 is a funnel arrangement 6 below which a waste receptacle 7 may be positioned.

Provided on the top of cabinet 2 is a pneumatic cylinder 8 which serves to move a crusher plate 9 upwardly and downwardly within the cabinet 2.

The apparatus is such that cylinder 8 can only be operated when door 4 is closed. For this purpose, the hinge arrangement of door 4 comprises spindles 1 0a and lOb extending above and below the inner vertical edge of door 4. The lower spindle 1 Oa (which is rotationally fast with the door) is journalled in the base of the cabinet 2.

The upper spindle lOb is journalled in the top of the cabinet 2 and extends into a housing 11 provided on top of the cabinet 2. The end of spindle lOb within the housing 11 is rotationally fast with a cam arrangement 12 (see insert on Fig. 1) also located in the housing 11. The cam arrangement is operatively associated with a cam follower 13 on an arm 14 mounted on a pneumatic switching valve 15, also located in housing 11. This valve controls the supply of air to operate the pneumatic cylinder 8.

Fig. 2 illustrates the position of the cam arrangement when door 4 is open.

The cam arrangement 12 incorporates a depression 16 in which the cam follower 13 only locates when the door 4 is shut. Valve 15 is biased by a spring 1 spa towards the cam arrangement 12 and with the door shut, is able to move to a position at which air is supplied (in a manner described more fully below) to the cylinder 8. With the door open, valve 15 is moved (by the action of cam 12 against cam follower 13) against the bias so that line 22 is isolated from line 23 and air cannot be supplied to cylinder 8.

The positioning of cam 12 in the housing 11 is such that it is inaccessible to an operator of the apparatus and therefore the door 4 must be shut before the apparatus can be operated.

In operation of the apparatus 1, a can to be crushed is placed "upside down in cabinet 2 so that any liquid remaining in the cam drains therefrom and passes through grid 6 into waste receptacle 7 via funnel 6. Door 4 is now closed which allows valve 15 to be moved to a position at which air can be supplied to the cylinder 8. The cylinder now moves the crusher plate 9 downwards so as to collapse the can before the crusher plate is returned to the upper position. The door 4 may now be opened to remove the collapsed can so that the above described operation may be repeated.

The control arrangement for the apparatus is illustrated in Fig. 2.

This control arrangement is illustrated for the condition of the apparatus in which door 4 is open and comprises four pneumatic switching valves 17, 18, 19 and 20 interconnected by various air supply lines in the manner to be described.

Valve 17 serves to supply air from line 28 either via line 29 to one side of cylinder 8 or via line 30 to the other side of the cylinder. Supply of air along line 29 causes extension of cylinder 8 whereas supply via line 30 effects retraction of the cylinder. during extension, air from the bottom side of cylinder 8 is vented via restrictor 3 1 on valve 17 whereas during retraction air from the upper side of the cylinder is vented via restrictor 36.

The switching of valve 17 is controlled by air pressure in lines 27 and 35. air pressure in line 27 switches valve 1 7 to a position at which lines 28 and 29 are in communication to effect extension of the cylinder. Air pressure in line 35 switches valve 17 so that lines 28 and 30 are in communication to effect retraction of the cylinder 8.

When door 4 is opened, valve 17 is at a "neutral" position (as controlled by two opposed springs 1 7a and 17b) so that there is no air supply path (through valve 17) to the cylinder 8.

Valve 18 serves to control the position of valve 17 for supplying air to one side or the other of cylinder 8. Valve 18 is switched by air pressure in line 25 from the condition illustrated in Fig. 2 to a position at which lines 26 and 27 are in communication. Valve 18 is returned to the condition illustrated in Fig. 2 (in which lines 26 and 35 are in communication) by pressure in line 34.

Valve 19 is biased to the position shown in Fig. 2 (at which lines 24 and 25 communicate) by a spring 19a. The valve 19 may be moved against this biasing force (to a position at which line 25 is vented) when sufficient air pressure (e.g. 45 psi) is present in line 32.

Valve 20 is biased to the position shown in Fig. 2 (at which line 34 is vented) by a spring 20a and is switched by a small air pressure (e.g. 1 psi) in line 37 to a position at which lines 33 and 34 are in communication.

The apparatus is operated by an air supply represented at 21. Valve 1 5 is connected via a line 22 to the air supply 21. When door 4 is opened. the position of cam follower 13 on the cam 12 is such that valve 15 is urged against the bias to a "closed" position at which lines 22 and 23 do not communicate so that air from supply 21 does not pass through the valve 15.

Assume now that door 4 is moved to the closed position. The cam follower 13 then rests in depression 16 on cam 12 allowing the valve 15 to be moved by the biasing force of spring 1 5a to a position at which air from line 22 passes through valve 15 into line 23.

Air from line 23 then passes via line 24 through valve 19 and into line 25.

Valve 18 is thus switched to a position such that air passes via lines 22 and 26 through valve 18 into line 27. The air in line 27 causes valve 17 to be moved to a position such that air is supplied (via lines 22 and 28) through valve 17 into line 29.

The air in 29 causes the cylinder 8 to effect a downward stroke so that a can provided in cabinet 2 may be crushed by the plate 9.

During the downwards stroke of the cylinder, air is exhausted from the nondriven side of the cylinder via line 30 through restrictor 31 on valve 17. Air in line 30 also enters line 37 such that valve 20 is urged against the biasing force of spring 20a and maintained in position shown in Fig. 2 (i.e. line 34 is vented).

During the course of the downward stroke, air pressure builds up in line 32 and causes valve 19 to be moved against a biasing force provided by spring 19a to a position at which line 25 is vented. This does not effect the position of valve 18.

At the end of the downward stroke of cylinder 8, there is no longer air pressure in lines 30 or 37. Valve 20 is now urged by spring 20a to a position at which air is fed via lines 22, 23 and 33 into line 34. This causes the position of valve 18 to be switched so that air from supply 21 is now able to pass (through lines 22, 23 and 26) via valve 18 into lines 35. This causes the position of valve 17 to be switched so that air from line 28 now passes into line 30 to cause the cylinder to effect an upward working stroke. Since line 30 is now pressurised, there is also air pressure in line 37 which causes valve 20 to be switched back to the position shown in Fig. 2 thus allowing the previously pressurised line 34 to vent without altering the position of valve 18.

During the upward stroke of the cylinder, air from the upper side of the cylinder 8 passes into line 29 and through restrictor 36 provided on valve 17.

Once the plate 9 has reached its upper limit position, the cycle is complete and the door may be opened. Opening of the door 4 causes the valve 15 to be moved back to a position at which the air supply can no longer feed through valve 15. At this position, line 23 is vented which allows valve 17 to move back to the "neutral" position illustrated in Fig. 2. Therefore cylinder 8 cannot be operated.

The apparatus is also provided with a manual drain valve 38 to make the system safe prior to any work being carried out on the system. If such work is to be carried out, then the mains air supply is isolated and the drain valve 38 opened. This dissipates the pressure in the system so that the necessary work may be effected.

A number of modifications may be made to the illustrated apparatus. Thus for example, the apparatus may incorporate a tray (not shown) provided below the grid 5 for collecting waste liquid from the cans. In this case, the funnel 6 would be omitted.

Claims (11)

1. Apparatus for compressing empty containers comprising a cabinet, a door pivotally mounted on the cabinet, compression means for effecting compression of a container positioned in the cabinet, and a control system for controlling operation of the compression means wherein the pivotal mounting of the door incorporates a cam which is rotated by opening and closing of the door and the control system incorporates switching means operatively associated with the cam such that closure of the door permits operation of the compression means and opening of the door prevents such operation.

2. Apparatus as claimed in claim 1 wherein the cam and the switching means are positioned in a housing provided on the cabinet.

3. Apparatus as claimed in claim 1 or 2 wherein the cam is provided on a spindle which is rotationally fast with the door and is coaxial with the pivotal mounting thereof.

4. Apparatus as claimed in claim 3 wherein said spindle provides part of the pivotal mounting of the door.

5. Apparatus as claimed in any one of claims 1 to 4 wherein the control system is such that upon closure of the door, the compression means automatically effects a working cycle of strokes so as firstly to compress a container within the cabinet and then return to its original position.

6. Apparatus as claimed in any one of claims 1 to 5 wherein the compression means comprise a fluid actuated cylinder and the switching means is a fluid control valve.

7. Apparatus as claimed in claim 6 wherein the cylinder is pneumatically operated.

8. Apparatus as claimed in any one of claims 1 to 7 comprising a grid in the base of the cabinet and liquid collection means below the grid.

9. Apparatus as claimed in claim 8 wherein the liquid collection means is a funnel member.

10. Apparatus as claimed in claim 8 wherein the liquid collection means is a tray.

11. Apparatus for compressing empty containers substantially as hereinbefore described with reference to the accompanying drawings.