GB2028281A - Improved sack separating apparatus - Google Patents

Abstract

According to the invention there is provided an improved device for removing an end sack from a generally vertically located stack of sacks (1) shown in plan in Figure 4. The stack of sacks is supported by restraints (4) on the edges of an end sack and this end sack is removed by means of suction cups (20) mounted on a support (15, 19) so that they can be bent back to bow the sack about the support. The whole assembly together with the separate sack is then liftable and retractable so that the sack may be presented for further handling. <IMAGE>

Description

SPECIFICATION Improved sack handling machine This invention relates to sack handling machines.

United States Patent Specification 4086746, which corresponds to our co-pending application 24097/76, describes and claims a machine for presenting bags successively to a filling aperture, comprising means for supporting a stack of bags with each bag in a generally vertical plane, means for separating at least a portion of an end bag of the stack from the remaining bags of the stack, means engaging the separated portion of such bag to lift the bag until an upper marginal portion is clear of the stack, suction means for engaging opposed sides of the upper marginal portion of the bag, means for separating the said suction means to open the bag, and means for transporting the said suction means to carry the bag from the stack for presentation to the filling aperture.

The separating means described and claimed includes suction cups to engage the exposed face of the end bag and separate it from the stack, and guides may be provided to assist in bowing of the bag so separated.

The arrangement described has been commercially successful but for larger sizes of bags in particular it has been found that the separation is not as satisfactory as might be desired. The present invention is directed to the provision of an improved separating arrangement which is more positive in action and gives greater reliability over a wide range of such sizes.

According to the present invention, there is provided a sack handling machine for sequentially separating one sack from a stack of sacks arranged in generally vertical planes, comprising means for supporting a stack of sacks in generally vertical plane said supporting including abutment means for engaging edges of an end sack of the stack while leaving most of the outer face of the end sack exposed, means for drawing the end sack away from the stack and means for lifting the drawing means together with the end sack to position the sack for further handling, in which the drawing means includes suction cups mounted on support means hingedly mounted on opposite sides of a spine member with at least one suction cup on each side of the spine member, means for advancing and retracting the support means and spine member and means for controlling the movement of the support means and spine member and the application of a suction to the cups whereby the support means and spine member are advanced bodily so that the suction cups engage the end sack of the stack, the support means are retracted alone to withdraw the edges of the sack from the abutment means and to bend the sack back about the spine member, and to raise the sack and drawing means bodily and straighten the sack for further handling.

The invention will be further described with reference to the accompanying diagrammatic drawings, in which Figure 1 is a side elevation of a sack handling machine according to the preferred form of the invention; Figure 2 is an elevation of the machine of Figure 1 with a stack of sacks omitted for clarity of illustration; and Figures 3, 4and 5 are partial plan view illustrating the sequence of operations involved in separating a sack from the stack.

The drawings show a stack 1 of sacks which is supported on an inclined support or sack tray 2 so that the sacks are fed downwardly by gravity towards a take-off point. The sack tray 2 is also laterally inclined as shown in Figure 2 so that the sacks are tilted within their vertical plane so that they can be transported in this position to a filling spout or like and then returned to their normal vertical position at the filling spout. The mechanism for achieving this stage in the sack handling is not described in the present application since it forms no part of the present invention, but an apparatus for achieving this end may be seen in the United States Patent Specification 4 086 746, to which previous reference has been made.

On the sack tray, the sacks are guided by guide rails 3 and supported at the sack take-off point by side restraining members 4 mounted between the guide rails 3 on a particular side and extending inwardly therefrom to engage and support the side edges of the sacks, as can be seen from figures 3,4 and 5. The stack of sacks is held in its vertical position by a sliding trolley or back stop 5 running on the sack tray 2 by means of wheels 6, and also by a central wheel stop 7 which prevents the stack of sacks collapsing and at the same time facilitates lifting of the leading sack by limiting the frictional restraint to which it is subjected.

An assembly for removing the end sack from the stacks 1, i.e. the end nearest the side restraining members 4, is mounted on a plate 11 which is adapted to be moved in guides (not shown) on a generally vertical path both upwards and downwards by means of a double acting pneumatic cylinder 12. The plate 11 carries bearings 13 for a pair of slide rails 14 which are rigidly connected to a spine member 15 (see Figures 2 to 5 from which the details of the assembly have been omitted) at the ends remote from the spine 15, the slide rails 14 carry a back plate 16which is actuated by a pneumatic cylinder 17 forforward and backward motion to move the spine towards and away from the stack.Mounted on the back plate is a further pneumatic cylinder 17 connected by a bifurcated linkage 18 to a pair of wings 19 hingedly mounted on the spine as illustrated particularly in Figure 2 and each carrying a suction cup or a group of suction cups 20 for engagement with the end sack of the stack 1. The wings 19 are adapted to be moved by means of the linkage 18 between a position as illustrated in Figures 3 and 5 in which they are substantially coplanar with the suction cups 20 somewhat ahead of the spine 15 and its restracted position as shown in Figure 4 in which the suction cups 20 are behind the spine 15 and the wings 19 are folded back.In operation to remove a sack from the stack 1, the suction cups start in the coplanar position the cylinder 1 6a is actuated to advance the spine and wings bodily to the position shown in Figure 3 with the cups 20 in engagement with the end sack. When this motion is completed, suction is applied at the cups 20 and the cylinder 17 is actuated to withdraw the wings to the figure 4 position thereby freeing the edges of the sack from the side restraining members 4 and bending the sack about the spine 15 as shown in Figure 4. This bending back of the stack gives considerable vertical stiffness and when the sack has been pulled clear of the side restraining members 4, the cylinder 12 is actuated to raise the assembly bodily with the plate 11 so that the end sack is pulled over the wheel stop 7 and its upper edge is caused to protrude above the stack 1.

The cylinder 16a is then actuated to withdraw the spine, and at the same time the cylinder 17 is actuated to advance the wings with respect to the spine so that the original position of the assembly of spine and wings is achieved but with the sack now held clear of the stack and somewhat elevated therefrom. The sack is then in position to be withdrawn by a further suction cup device for transport to a filling spout of the like and when engagement of this device, which may include suction cups, has been achieved, the vacuum at the suction cups 20 is cut off and the sack may be withdrawn. The cylinder 12 is then actuated to lower the assembly to restart the cycle.

The arrangement described is of wholly pneumatic operation, since this is generally more convenient to obtain, but it will be appreciated that the cylinders could be hydraulic if convenient. Control of the sequence of operations is entirely automatic and the completion of one stage in the cycle triggers the next through appropriate automatic controls so that appropriate interlock is obtained and should the machine fail, it will stop and the point of failure can be easily identified.

Various modifications may be made within the scope of the invention.

Claims (7)

1. A sack handling machine for sequentially separating one sack from a stack of sacks arranged in generally vertical planes, comprising means for supporting a stack of sacks in generally vertical plane said supporting including abutments means for engaging edges of an end sack of the stack while leaving most of the outer face of the end sack exposed, means for drawing the end sack away from the stack and means for lifting the drawing means together with the end sack to position the sack for further handling, in which the drawing means includes suction cups mounted on support means hingedly mounted on opposite sides of a spine member with at least one suction cup on each side side of the spine member, means for advancing and retracting the support means and spine member and means for controlling the movement of the support means and spine member and the application of a suction to the cups whereby the support means and spine member are advanced bodily so that the suction cups engage the end sack of the stack, the support means are retracted alone to withdraw the edges of the sack from the abutment means and to bend the sack back about the spine member, and to raise the sack and drawings means bodily and straighten the sack for further handling.

2. A machine as claimed in claim 1, in which the drawing means is pneumatically operated.

3. A machine as claimed in claim 1 or 2, having a respective set of suction cups on each side of the spine member.

4. A machine as claimed in claim 3 in which each set of suction cups are mounted on a common support.

5. A machine as claimed in claim 4, in which each set of suction cups consist of three section cups.

6. A machine as claimed in claim 1,2,3,4 or 5, in which the drawing means is mounted for bodily raising and lowering and comprises a mounting plate carrying bearings for a slidable assembly including the spine and control cylinder for the suction cups supporting means.

7. A sack holding machine substantially as hereinbefore described with reference to the accompanying drawings.