GB1570019A

GB1570019A - Scrap shears

Info

Publication number: GB1570019A
Application number: GB4771177A
Authority: GB
Original assignee: Lindemann Maschinenfabrik GmbH
Current assignee: Lyndex Recycling Systems Ltd
Priority date: 1976-12-03
Filing date: 1977-11-16
Publication date: 1980-06-25
Also published as: JPS5371391A; DE2654751A1; DE2654751C3; FR2372673B1; DE2654751B2; JPS6128444B2; FR2372673A1

Description

(54) IMPROVEMENTS IN SCRAP SHEARS (71) We, LINDEMANN MASCH INENFABRIK GmbH, a German Company, of Erkrather Strasse 401, 4000 Dusseldorf - 1, West Germany, do hereby declare the invention, for which we pray that a patent may be granted to us and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to scrap-cutting shears of the kind comprising a frame having an opening for the scrap to be sheared to pass through, a movable power-driven knife carriage which is mounted in the frame and carries a knife which, in use, co-operates with a counter-knife, and a holding-down device for holding down the scrap while it is sheared, the holding down device being located in the path of the scrap to the knives.

Such a shears is disclosed in German Specification No. 1,402,382. The shears disclosed in this Specification has a stationary frame and the opening is bounded at the bottom by a stationary lower knife firmly fixed to the frame. The knife carriage with an upper knife fixed thereto is guided in the frame. The upward and downward movements of the knife carriage are effected by means of a hydraulic cylinder, which is connected at one end, preferably the cylinder end, to the frame, while the other end, that is preferably the rod end, is connected to the knife carriage which, during cutting, is guided past the cutting edge of the lower knife.

The holding-down device is provided to prevent tilting and jamming of pieces of scrap within the opening. This device can be moved up and down independently of the knife carriage also by means of a hydraulic cylinder.

This known form of shears fulfils the demands made of it, but has a comparatively expensive and heavy driving installation in that the hydraulic cylinders in total have to apply a higher force than is necessary for carrying out the cutting operation.

The aim of the present invention is to provide a shears of the kind described which is capable of handling equal or even greater thicknesses of cut than the existing shears with a smaller installed hydraulic power.

To this end, according to this invention, in a scrap-cutting shears of the kind described, the knives consist of a lower knife fixed to a movable knife carriage, and an upper knife fixed to another movable knife carriage which also carries the holding-down device, a first of these two knife carriages being mounted in the frame and the second carriage being mounted in the first carriage.

With this arrangement, the additional hydraulic installation and the hitherto necessary separate force application for the holdingdown device is no longer needed, because the holding-down device is combined structurally with the upper knife and can thus share its drive. The function of holding down and of the cutting of the scrap can therefore be carried out by one drive.

Preferably, the knife carriages are connected to each other by a hydraulic cylinder which acts between the carriages in such a manner that scrap to be sheared acts as a stop for the knife carriage which carries the holding-down device and the cylinder then moves the other carriage relative to the carriage which carries the holding-down device.

With this general arrangement, two alternative forms of embodiment are possible. In one embodiment, the lower knife is carried by the first carriage and the holding-down device and the upper knife are carried by the second knife carriage which is connected by the cylinder drive to the first knife carriage and are movably guided in the latter. With this arrangement, the first knife carriage and the holding-down device with the upper knife are so-to-speak clamped to each other by the cylinder, the cylinder preferably hav ing its cylinder part connected to the first knife carriage and its rod part connected to the holding-down device.

Alternatively, the upper knife with the holding-down device can be fixed to the first knife carriage, while a support for the lower knife which forms the second carriage is connected by the cylinder to the first knife carriage and is movably guided in the latter, the cylinder is a preferred form of embodiment of this alternative having its cylinder part connected to the first knife carriage and its rod part connected to the lower knife support. This alternative calls for location of the cylinder into the lower part of the frame, without any fundamental modification of the sequence of movement of the components which will be explained later. Such an embodiment is preferred in certain cases, for reasons of space saving.

When the cylinder is extended, in the first alternative, the holding-down device with the upper knife and then the first carriage with the lower knife are moved one after the other in directions opposite to and towards one another, whereas with the second alternative, first of all the first carriage together with the upper knife and then the lower knife support together with the lower knife are moved towards one another.

Preferably, in the first alternative embodiment, a stop for locating the holding-down device in its upper limiting position and a further stop for locating the first carriage in its lower limiting position are provided on the frame. In this, the result is attained that, when the cylinder is retracted, the holdingdown device bears against the upper stop and the first carriage against the lower stop, so that a defined opening for the scrap, which is to be cut, to pass through is ensured. The lower knife can be brought into alignment with the top surface of a table of the shears.

The coupling together with regard to the application of force and to movement of the upper and lower knives by means of the cylinder through the carriages, produces in a surprisingly simple manner a quasiautomatic sequence of operations, comprising pre-compaction and cutting of the scrap, which previously had to be separately regulated. It is possible in a simple manner in an embodiment of this invention to regulate the degree of pre-compaction by providing a holding cylinder which acts upon the first carriage or on the lower knife support. The compressive force produced by the holding cylinder has to be overcome by that of the cylinder which acts between the carriages when the scrap compacting operation has been completed and before shearing commences.

Instead of providing a holding cylinder, the first carriage or the lower knife support may be connected by a frictional connection to the frame, so that, when the cylinder which acts between the carriages is pressurised with hydraulic fluid, the holding-down device first of all carries out the compaction of the scrap before the frictional connection is overcome.

Both the above-mentioned measures have the effect that the lower knife only commences to move towards the upper knife which is secured to the holding-down device when the desired compaction of the scrap has been achieved, or when the cylinder which acts between the carriages exerts a force upon the scrap which exceeds the force of the holding cylinder or the force produced by the frictional connection between the first carriage or the lower knife support and the frame.

In many applications it is desirable to provide two hydraulic cylinders which are preferably connected by their cylinder parts to the first carriage and by their rod parts to the holding-down device or to the lower knife support, the cylinders being spaced laterally apart from each other. In this way the result can be attained that the upper knife or the lower knife can be lowered and raised in an inclined position by supplying differing pressures to the two cylinders and can also be lowered or raised in a rocking manner by alternating the pressures to the two cylinders. In this way the possibility is provided of adapting the sequence of operations of the shears in an optimum manner to the differing resistances of the scrap which is to be sheared.

Some examples of scrap-cutting shears in accordance with the invention are illustrated in the accompanying drawings, in which: Figure 1 is a vertical section through a first example; Figure 2 is a partly sectional plan of the first example showing also the components carried by the frame; Figure 3 shows the left-hand portion of Figure 2, but modified by the provision of devices suitable for a frictional connection between the frame and knife carriage; Figures 4 to 6 are diagrammatic representations of the shearing operation of the first example; Figure 7 is an elevation of the upper knife drive of a second example; and, Figure 8 is a view corresponding to part of Figure 1 but showing an alternative arrangement of a cylinder drive.

As shown in Figure 1, a knife carriage 2 is longitudinally slidable in a stationary frame 1 which contains an opening 3 for the passage of scrap, the opening 3 being bounded at the bottom end by a lower knife 4 on the carriage 2. The knife carriage 2 is shown in Figure 1 in its lower limiting position in which it bears against a stop 5 of the frame 1.

A hydraulic cylinder 6 has its cylinder part 7 fixed to the knife carriage 2. A rod part 8 of the cylinder 6 carries a knife carriage 9, which also includes a holding-down device 9a, to which an upper knife 10 is fixed. The holding-down device 9a is shown in Figure 1 in its upper limiting position, in which the knife carriage 9 bears against a stop 11. The knife carriage 9 is slidably guided in the knife carriage 2, so that when the cylinder 6 is extended, first of all the holding-down device 9a is lowered until it meets a resistance, namely the scrap to be compacted and cut, so that when the scrap compaction has been completed and the holding-down device 9a can move no further downwards, the cylinder 6 raises the knife carriage 2 with its lower knife 4 and draws the lower knife 4 past the upper knife 10 to cut the scrap..

Additionally, the knife carriage 2 may be acted upon by a holding cylinder 12, which is fixed to the frame in a manner not shown, in such a way that the knife carriage 2 does not rise until a predetermined scrap compaction has been effected by means of the holdingdown device 9a. The holding cylinder 12 can be formed as a plunger and serves for maintaining a counter-force to ensure scrap compaction by the holding-down device 9a and to assist in holding down the scrap during the shearing operation.

An effect similar to that of the holding cylinder 12 can be achieved, as shown in Figure 3, by applying a frictional force between the knife carriage 2 and the frame by means of hydraulic cylinders 13 and 14.

The sequence of operations is explained with reference to Figures 4 to 6. As shown in Figure 4, the holding-down device 9a occupies its upper limiting position, determined by the fixed stop 11, while the knife carriage 2 is in its lower limiting position, bearing against the stop 5.

Under these conditions scrap 15 to be sheared is pushed to the left in the direction of an arrow 16, whereupon, as the cylinder 6 is extended, the holding-down device 9a descends as shown in Figure 5 on to the scrap 16 and, after scrap compaction as determined by the force of the holding cylinder 12 or after a corresponding pressure rise in the cylinder 6, the device 9a comes to rest. After this, the knife carriage 2 as shown in Figure 6 is pulled upwards by the cylinder 6 in the direction of the arrow 17 and the lower knife 4 is moved past the upper knife 10 and shears the scrap 15. Depending upon the amount by which the knife carriage 2 is raised, a plunger 18 is retracted further into the holding cylinder 12.

In a frame 19 shown in Figure 7, a knife carriage 20 is vertically movably guided together with a lower knife 21. With the assistance of an extension 22, an upper knife 23 is pivotally and slidably mounted by a slide block 24 and a journal 25. By extending cylinders 26 and 27, a lowering of the upper knife 23 is effected. In order to obtain an inclined position of the upper knife 23 and thereby to enable larger thicknesses of cut to be achieved, it is only necessary for one of the two cylinders 26 or 27 to be pressurised with a higher or a lower pressure, so that the upper knife 23 adopts an inclined position.

It is also possible to pressurise the two cylinders 26 and 27 with alternating differing pressures, so that the lowering of the upper knife 23 takes place in a rocking manner and an optimum adaptation to differing resistances during scrap cutting is possible.

When the knife 23 can move no further downwards owing to the holding-down device to which it is fixed being blocked by scrap, the cylinders 26 and 27 move the carriage 20 and the knife 21 upwards to effect shearing.

As shown in Figure 8, a cylinder or cylinders 28 can also be connected directly to a lower knife carriage 29 carrying a lower knife 30, a rod part 31 being connected to the carriage 29 and a cylinder part 32 to a knife carriage 35 which carries an upper knife 33 and a holding-down device 34. The knife carriage 35 is, as in the example of Figure 1, movably guided in a frame 36. The lower knife carriage 29 can be brought also into an inclined position by means of the cylinders 28, when two are provided, to enable a cut which extends progressively along the length of the knife to be executed.

Two holding cylinders 38 are mounted upon the frame 36 above an opening 37 of the shears, piston rods 39 of these cylinders when extended bearing against the lower knife carriage 29 and thus producing the same effect as the holding cylinder 12 of Figure 1. The effect caused by the holding cylinders 38 can also be achieved by frictional loading of the lower knife carriage 29, as can be seen in Figure 3, references 13 and 14. In the starting position shown in Figure 8, the lower knife carriage 29 rests upon limit stops, not shown, so that the lower knife when in a horizontal position is in alignment with a table 40 of the shears. When the cylinders 28 are extended, the lower knife carriage 29 is initially prevented by the holding cylmders 38 from moving upwards; so that the knife carriage 35 is moved downwards until the upper knife 33 and holding-down device 34 exert upon the scrap 41 a force exceeding the force of the holding cylinders 38. The lower knife support 29 then moves upwards, as the piston rods 39 are retracted into the holding cylinders, until the scrap 41 is sheared between the lower knife 30 and the upper knife 33.

WHAT WE CLAIM IS: 1. Scrap-cutting shears comprising a frame having an opening for the scrap to be sheared to pass through, a movable powerdriven knife carriage which is mounted in the

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. the cylinder 6 carries a knife carriage 9, which also includes a holding-down device 9a, to which an upper knife 10 is fixed. The holding-down device 9a is shown in Figure 1 in its upper limiting position, in which the knife carriage 9 bears against a stop 11. The knife carriage 9 is slidably guided in the knife carriage 2, so that when the cylinder 6 is extended, first of all the holding-down device 9a is lowered until it meets a resistance, namely the scrap to be compacted and cut, so that when the scrap compaction has been completed and the holding-down device 9a can move no further downwards, the cylinder 6 raises the knife carriage 2 with its lower knife 4 and draws the lower knife 4 past the upper knife 10 to cut the scrap.. Additionally, the knife carriage 2 may be acted upon by a holding cylinder 12, which is fixed to the frame in a manner not shown, in such a way that the knife carriage 2 does not rise until a predetermined scrap compaction has been effected by means of the holdingdown device 9a. The holding cylinder 12 can be formed as a plunger and serves for maintaining a counter-force to ensure scrap compaction by the holding-down device 9a and to assist in holding down the scrap during the shearing operation. An effect similar to that of the holding cylinder 12 can be achieved, as shown in Figure 3, by applying a frictional force between the knife carriage 2 and the frame by means of hydraulic cylinders 13 and 14. The sequence of operations is explained with reference to Figures 4 to 6. As shown in Figure 4, the holding-down device 9a occupies its upper limiting position, determined by the fixed stop 11, while the knife carriage 2 is in its lower limiting position, bearing against the stop 5. Under these conditions scrap 15 to be sheared is pushed to the left in the direction of an arrow 16, whereupon, as the cylinder 6 is extended, the holding-down device 9a descends as shown in Figure 5 on to the scrap 16 and, after scrap compaction as determined by the force of the holding cylinder 12 or after a corresponding pressure rise in the cylinder 6, the device 9a comes to rest. After this, the knife carriage 2 as shown in Figure 6 is pulled upwards by the cylinder 6 in the direction of the arrow 17 and the lower knife 4 is moved past the upper knife 10 and shears the scrap 15. Depending upon the amount by which the knife carriage 2 is raised, a plunger 18 is retracted further into the holding cylinder 12. In a frame 19 shown in Figure 7, a knife carriage 20 is vertically movably guided together with a lower knife 21. With the assistance of an extension 22, an upper knife 23 is pivotally and slidably mounted by a slide block 24 and a journal 25. By extending cylinders 26 and 27, a lowering of the upper knife 23 is effected. In order to obtain an inclined position of the upper knife 23 and thereby to enable larger thicknesses of cut to be achieved, it is only necessary for one of the two cylinders 26 or 27 to be pressurised with a higher or a lower pressure, so that the upper knife 23 adopts an inclined position. It is also possible to pressurise the two cylinders 26 and 27 with alternating differing pressures, so that the lowering of the upper knife 23 takes place in a rocking manner and an optimum adaptation to differing resistances during scrap cutting is possible. When the knife 23 can move no further downwards owing to the holding-down device to which it is fixed being blocked by scrap, the cylinders 26 and 27 move the carriage 20 and the knife 21 upwards to effect shearing. As shown in Figure 8, a cylinder or cylinders 28 can also be connected directly to a lower knife carriage 29 carrying a lower knife 30, a rod part 31 being connected to the carriage 29 and a cylinder part 32 to a knife carriage 35 which carries an upper knife 33 and a holding-down device 34. The knife carriage 35 is, as in the example of Figure 1, movably guided in a frame 36. The lower knife carriage 29 can be brought also into an inclined position by means of the cylinders 28, when two are provided, to enable a cut which extends progressively along the length of the knife to be executed. Two holding cylinders 38 are mounted upon the frame 36 above an opening 37 of the shears, piston rods 39 of these cylinders when extended bearing against the lower knife carriage 29 and thus producing the same effect as the holding cylinder 12 of Figure 1. The effect caused by the holding cylinders 38 can also be achieved by frictional loading of the lower knife carriage 29, as can be seen in Figure 3, references 13 and 14. In the starting position shown in Figure 8, the lower knife carriage 29 rests upon limit stops, not shown, so that the lower knife when in a horizontal position is in alignment with a table 40 of the shears. When the cylinders 28 are extended, the lower knife carriage 29 is initially prevented by the holding cylmders 38 from moving upwards; so that the knife carriage 35 is moved downwards until the upper knife 33 and holding-down device 34 exert upon the scrap 41 a force exceeding the force of the holding cylinders 38. The lower knife support 29 then moves upwards, as the piston rods 39 are retracted into the holding cylinders, until the scrap 41 is sheared between the lower knife 30 and the upper knife 33. WHAT WE CLAIM IS:

1. Scrap-cutting shears comprising a frame having an opening for the scrap to be sheared to pass through, a movable powerdriven knife carriage which is mounted in the

frame and carries a knife which, in use, cooperates with a counter-knife, and a holding-down device for holding down the scrap while it is sheared, the holding-down device being located in the path of the scrap to the knives, wherein the knives consist of a lower knife fixed to a movable knife carriage and an upper knife fixed to another movable knife carriage which also carries the holding-down device, a first of these two knife carriages being mounted in the frame and the second carriage being mounted in the first carriage.

2. Shears according to claim 1, in which the knife carriages are connected to each other by a hydraulic cylinder which acts between the carriages in such a manner that scrap to be sheared acts as a stop for the knife carriage which carries the holding-down device and the cylinder then moves the other carriage relative to the carriage which carries the holding-down device.

3. Shears according to claim 2, in which the cylinder has its cylinder part connected to the first knife carriage and its rod part to the first knife carriage and its rod part to the second carriage which carries the holdingdown device.

4. Shears according to claim 2, in which the cylinder has its cylinder part connected to the first knife carriage and its rod part connected to the second carriage which carries the lower knife.

5. Shears according to claim 3, in which, when the cylinder is extended, the holdingdown device together with the upper knife, and then the knife carriage which carries the lower knife are successively moved in opposed directions towards each other.

6. Shears according to claim 4, in which, when the cylinder is extended, the first knife carriage which carries the upper knife and then the carriage which carries the lower knife together with the lower knife are successively moved in opposite directions towards each other.

7. Shears according to any one of claims 1 to 3 or claim 5, in which a stop is provided on the frame for locating the holding-down device in an upper limiting position and a further stop is provided on the frame for locating the first knife carriage in its lower limiting position.

8. Shears according to claim 7, in which, when the cylinder is retracted, the holdingdown device and the first carriage bear against their stops.

9. Shears according to claim 2, or any one of claims 3 to 8 when dependent on claim 2, in which, when the cylinder is extended, the upper and lower knives overlap each other.

10. Shears according to any one of claims 1 to 9, in which a holding cylinder acts upon the carriage which carries the lower knife, the force produced by the holding cylinder being overcome by that of the cylinder acting between the carriages when the scrap to be sheared has been compacted by the holding-down device.

11. Shears according to any one of claims 1 to 9, in which the carriage which carries the lower knife is connected by a frictional connection to the frame.

12. Shears according to claim 2 or any one of claims 3 to 11 when dependent on claim 2, in which two cylinders act between the two carriages and are spaced laterally apart from each other, the cylinders being pivotally mounted to allow the knives to move skew to each other.

13. Shears according to claim 12, in which the upper knife carriage has a projection by which it is pivotally journalled b means of a trunnion-mounted slide block forming a guide for the projection.

14. Shears according to claim 12 or claim 13, in which by differentially pressurising the two cylinders, the upper knife or lower knife can be lowered or raised in an inclined position.

15. Shears according to any one of claims 12 to 14, in which by alternately pressurising the two cylinders, the upper knife or the lower knife can be moved in a rocking manner.

16. Shears accordingto claim 1, substantially as described with reference to Figures 1 and 2, or Figure 3, and Figures 4 to 6, or Figure 7 or Figure 8, of the accompanying drawings.