GB2023532A

GB2023532A - A Bundling Strap Removing Device

Info

Publication number: GB2023532A
Application number: GB7842406A
Authority: GB
Original assignee: Demag AG
Current assignee: Mannesmann Demag AG
Priority date: 1978-06-14
Filing date: 1978-10-30
Publication date: 1980-01-03
Also published as: DE2826026C3; GB2023532B; FR2428575B3; DE2826026A1; JPS54163197A; FR2428575A1; IT7919900A0; IT1111787B; DE2826026B2

Abstract

A bundle, for example a coil of sheet metal, is supported on a support bed 2 adjacent to a device for removing a bundling strap encircling the bundle. The device comprises a lever 3 capable of being pivoted about an axis 4 by power means 5 in the direction of arrow 6 to bring a cutting apparatus 7 and a gripper apparatus 9 carried on arm 8 into contact with the bundle. The cutting apparatus 7 incorporates hold-down means which press the strap against the bundle at circumferentially spaced apart locations and a chisel which is moved axially of the bundle to cut through the strap. The gripper apparatus incorporated a castellated head on which the severed strap is wound into a coil, and a stripper which removes the strap from the head to deposit it in a container 10 as the device is swung back into the left hand position shown in chain lines. <IMAGE>

Description

SPECIFICATION A Bundling Strap Removing Device This invention relates to a device for removing a bundling strap from, for example, a coil of metal sheet.

It is usual for a coil of metal sheet to be transported from a rolling mill held together by bundling straps wrapped tightly around the coil.

Before the coil can be processed the straps must be removed. Various methods and devices for removing the straps have been proposed and utilised but none is entirely satisfactory.

According to the present invention, a device for removing a bundling strap comprises hold-down means which in use press the strap against the coil at positions which are spaced apart in the direction circumferentially of the strap, a cutting tool movable into engagement with an edge of the strap at a position between those at which the strap is engaged by the hold-down means, and a gripper apparatus having a rotatable strap take-up member which is engageable with, and capable of winding up, the strap.

The cutting tool may resemble a chisel applied to the strap with its cutting edge generally normal to the coil. During the cutting action of the chisel, the materiai of the strap is found to bulge in the region of the notch being formed by the chisel.

Instead of retreating under the action of the chisel, the strap is held against the coil which serves as an abutment and ensures reliable cutting. Since the strap tends to bulge in the region of the notch, the cutting action takes place slightly away from the surface of the coil so that no damage is caused to the latter. Preferably, the cutting tool is caused to impact repeatedly during short intervals of time against the strap by a conventional compressed air operated impact applicance. Such applicances have long been commercially available and their use in the device provided by the present invention makes the preferred embodiment thereof especially economical. The free ends of the severed strap are held in place by the hold-down means so that the strap does not burst but is held in position until it is wound-up by the gripping apparatus.

Since the hold-down means continue to hold the strap in place until it has been taken over by the gripping apparatus the strap is gripped reliably.

The gripper apparatus may include a rotary head which is mounted on a shaft in cantilevered fashion and has castellated portions, each with a tapered end in the manner of a chisel or knife blade to enable it to engage beneath the strap.

The castellated portions are at least as long as the width of the strap on which the device is to operate. After the strap has been cut through, the head is movable in the direction parallel to the axis of the coil to bring one of the castellated portions beneath the strap, whereupon the head is rotated to wind the strap onto the outer surface of the head.

Preferably, the rotary head is associated with a stripper which, as the head is retracted, removes from the head the coil of strap wound thereon.

The strap is thus formed into a relatively compact coil which may be transferred easily to a scrap container.

Although the cutting and gripping apparatus may be mounted on any convenient structure which can be advanced towards and retracted from the coil, it is preferred for the apparatus to be carried on a lever or beam which can be swung towards and away from the coil and moved axially relative thereto. The device can thereby be brought rapidly into positions suitable for removing the straps and into use.

It wiil be appreciated that the invention may be utilised for removing bundling straps which hold together other metal products, provided that the bundle they surround is sufficiently rigid to enable the device to function satisfactorily.

The invention will now be described in greater detail but by way of example only with reference to the drawings, in which; Figure 1 is a view looking axially of a coil of sheet metal and showing the main part of a device embodying the invention, Figure 2 is a view of the device looking axially of the coil, Figure 3 is a view to a larger scale of part of the device viewed tangentially of the coil, Figure 4 is a view of the part of the device shown in Figure 3 but looking radially of the coil, Figure 5 consists of two views showing the cutting tool used in the device viewed in elevation and in plan, Figure 6 is a view viewed tangentially of the coil showing a gripper apparatus used in the device partly in section, and Figure 7 is a view from the left of Figure 6 of part of the strap gripper apparatus.

Referring to Figures 1 and 2, a coil 1 of sheet metal is held intact by a number of bundling straps A, one of which is shown. The coil is supported with its axis horizontal on a support bed 2. The invention may be carried out in connection with coils of differing diameters, a large diameter coil being shown in unbroken lines and a smaller diameter coil being shown in chain lines, and also in connection with bundles of other products. A device for removing a strap is located adjacent the support bed 2 in such a position that it may operate on a coil having any diameter within a predetermined range.

Mounted on the floor is a shaft 11 which extends parallel to the axis of the coil and on which a lever 3 is supported for movement about the axis 4 shown in Figure 1. The lever 3 and the parts associated therewith are movable along the shaft 11 in the direction parallel to the axis of the coil under the action of a power drive (not shown) connected to the lever 3 at 12 and capable of applying force thereto in the direction indicated by the arrows, A further power drive (not shown) is connected at 5 to an extension of the lever arm 3 (Figure 1) for the purpose of swinging the lever arm towards and away from the coil in the direction indicated at 6. The power means may be in the form of fluid operated piston and cylinder units.The operating part of the device consists of a cutting apparatus 7 at the end of lever 3 and shown diagrammatically in Figures 1 and 2 and a gripper apparatus shown diagrammatically at 9 in Figures 1 and 2 mounted on an arm 8 pivoted to the lever 3.

A container 1.0 is provided to receive the strap from the gripper apparatus 9 following movement of the device from the right-hand position shown in Figure 1 to the left-hand chain dotted line position, during which movement the gripper apparatus is displaced or swings freely on the lever 3 into position above the container.

The cutting apparatus shown diagrammatically at 7 in Figures 1 and 2 is shown iri greater detail and to a larger scale in Figures 3 to 5. The apparatus includes a guide 23 mounted at the end of the lever 3 and supporting a beam 18 for movement in the direction parallel to the axis of the coil under the action of piston and cylinder unit 19. The beam carries a cylinder 1 5 which is spring mounted at 16. Compressed air may be supplied to the cylinder 15 through an inlet 1 7 to cause the cylinder, in known fashion, to apply repeated biows to a cutting tool in the form of a chisel 14.Activation of the cylinder 1 9 thus causes the chisel to advance towards the left in Figure -3 and into contact with the strap "A" and simultaneous activation of the cylinder 1 5 causes the chisel to be made to impact the strap and to sever it. Also mounted on the guide are two holddown devices 22 located one on each side of the chisel. The devices 22 are supported in the housing 20 and are acted upon by power means in the form of a piston and cylinder unit 21 which by way of a suitable connection causes the holddown devices to press the strap against the strap.

The chisel is shown in greater detail in Figure 5 and has a guide portion 25 curved so as to slide along the surface of the coil and an upstanding cutting edge 24. The leading edge of the guide portion is disposed rearwardly of the cutting edge 24 and is shaped so as to engage beneath the strap on both sides of the notch made by the cutting edge as the chisal is forced to impact against the strap.

Referring now to Figure 6, the gripper apparatus 9 comprises a rotary head 26 mounted on a shaft capable of being advanced and retracted in the direction shown by the arrow 27, and associated means for driving the shaft in rotation. The head has sharp ended castellated portions 28, one or other of which is capable of penetrating under the loosened strap A as shown in Figure 7 as the head is advanced. Each castellated portion is at least as long as the strap is wide.

The side of the head remote from the castellated portions is wedge-shaped as indicated at 30. A fixed part 31 has a recess which is complementary to the wedge-shaped surface 30 so that when the head is retracted, the surface 30 comes to lie within the recess of the fixed part 31 which constrains the head to come to rest in a position in which one of the castellated portions rests against the surface- of the coil in a suitable position for engaging under the loosened strap during its next operating sequence.

A stripper device 33 spans the head when the latter is in its advanced position for the purpose of removing strip wound onto the head.

The device operates as follows:- A coil which is to be unstrapped is placed on the support bed 2 and the strap removing device brought into appropriate alignment with the first strap to be removed. A sensing device (not shown) determines the position of the strap. The lever 3 is then swung into the right-hand position shown in Figure 1 in which the hold-down devices press the strap onto the surface of the coil to restrain it from movement axially of the coil.

Compressed air is fed to the piston and cylinder unit 19 and to the cylinder 15 in order to advance the chisel 14 towards the strap and to cause it to impact repeatedly against the edge of the strap.

The chisel drives a notch into the edge of the strap which lifts slightly from the surface of the coil by virtue of the tendency of the strap to bulge in the vicinity of the notch. The strap is progressively cut through and the guide portion of the chisel penetrates beneath the strap to lift it further from the bundle.

After the strap has been cut through completely, the head 26 of the gripper apparatus is advanced from its rest position so that one of the castellated portions 28 engages beneath the strap. The head is then set in rotation and the hold-down devices simultaneously release the strap which is wound onto the head 26. As the winding up of the strap progresses, the lever 8 is swung away from the surface of the coil, and, after the strap has been completely wound-up, the head is moved back in the direction of the arrow 27 to the right of Figure 6. The device 33 shown in Figure .6 prevents the wound-up coil of strap from being carried back by the head 26 as the latter is retracted towards the right in that figure. The coil of strap is thus stripped from the head 26 preferably in the left-hand position in Figure 1 above the scrap container, so that the coil of strap is discharged into the container. The strap removing device is then advanced along a shaft 11 to the iocation of the next strap to be removed and the process repeated.

Claims

1. A device for removing a bundling strap comprising hold-down means operable to press the strap to be removed against the bundle at positions spaced apart in the direction circumferentially of the strap, a cutting tool movable in the direction axially of the bundle into engagement with the strap in the region between the positions at which the hold-down means engage the strap, and a gripper apparatus having a rotatable strap-take-up member engageable with the strap and operable to wind-up severed strap thereon.

2. A device as claimed in Claim 1, wherein the cutting tool is carried by a device which is operable to cause the tool to repeatedly impact against the strap.

3. A device as claimed in Claim 1 or Claim 2, wherein the gripper apparatus comprises a rotary head with castellations, each of which is tapered at its end to facilitate the engagement thereof between the strap and the bundle.

4. A device as claimed in Claim 3, including stripping means for removing a coiled strap from the head.

5. A device as claimed in any preceding claim, wherein the gripper apparatus and cutting apparatus are carried on a component pivotable into contact with the surface of the bundle and movable axially relatively thereto.

6. A strap removing device substantially in accordance with any embodiment herein described or illustrated.