SYSTEM FOR CHANGING THE HAMMERS OF A SHREDDER AND RELATIVE METHOD

Abstract

The invention relates to a system for changing the hammers of a shredder including a shredder with one or more covers and a rotating drum equipped with a plurality of hammers; a lifting system suitable to move said hammers and a control unit which controls both the opening of the shredder and the movements of the lifting system and preferably also the unlocking/locking of the hammers from/on the drum to allow their replacement. The system can be managed hydraulically with a single hydraulic supply. It is included to be able to control the system remotely or to include its automation according to a maintenance plan. A relative method for changing the hammers of a shredder is also disclosed.

Claims

1. A system for changing the hammers of a shredder comprising: (a) a shredder which in turn comprises (a1) a housing which defines a shredding chamber and which is equipped with one or more covers, and optionally drive rotors to drive the material to be shredded, which can be lifted and lowered by means of relative lifting devices, in particular hydraulic lifting devices; (a2) inside said housing a rotating drum equipped with a plurality of hammers; (a3) a first control system to control said lifting devices; (b) a lifting system, preferably hydraulically operated, suitable to move said hammers by means of a second control system in order to control the movements of said lifting system; (c) a control unit which controls both the first and the second control system.

2. The system for changing the hammers of a shredder according to claim 1, further comprising a remote control device to control said control unit.

3. The system for changing the hammers of a shredder according to claim 1, wherein said lifting devices are hydraulic lifting devices and said lifting system is hydraulically operated, and further comprising: (d) a hydraulic power unit that supplies both the hydraulic lifting devices and said lifting system with hydraulic operation.

4. The system for changing the hammers of a shredder according to claim 1, wherein said drum further comprises at least one lock, in particular at least one pin, to constrain said hammers to said drum, and wherein said system for changing the hammers of a shredder further comprises a locking/unlocking device of said hammers, in particular a pin extractor to extract and insert said at least one pin in said drum, to block/unblock said hammers which is controllable by said control unit.

5. The system for changing the hammers of a shredder according to claim 1, wherein said lifting system is a robotic arm.

6. The system for changing the hammers of a shredder according to claim 1, further comprising an electronic safety control for scanning the movement trajectory of said lifting system.

7. The system for changing the hammers of a shredder according to claim 1, wherein said hammers are identifiable by their position and expected life and wherein said control unit comprises a program that contains the maintenance plan of the hammers suitable to control the system for changing the hammers so as to replace one or more hammers or to reposition it/them so that its/their working faces are in a different position from the previous one automatically according to said maintenance plan.

8. The system for changing the hammers of a shredder according to claim 1, further comprising at least one storage device to house hammers which is accessible by this lifting system to take new hammers to be installed on the drum or to place used hammers extracted from the drum.

9. A method for changing the hammers of a shredder comprising the following steps: (i) providing a shredder with a rotating hammer drum and a lifting system of the hammers and a locking/unlocking device to block/unblock said hammers to/from said drum; (ii) opening said shredder; (iii) unlocking at least one hammer with said locking/unlocking device; (iv) operating said lifting system and extraction of a hammer at least partially worn from said drum; (v) alternatively (v-1) removing a completely worn hammer from said shredder, preferably placing it in a storage device, and providing said lifting system with a new hammer, preferably taken from another or said storage device and inserting said new hammer into said drum in the vacant position; or (v-2) repositioning of a partially worn hammer in the vacant position in said drum so that its working faces are in a different position from the one before extraction; (vi) locking said new or repositioned hammer with said locking/unlocking device; (vii) repetition of phases (iii) to (vi) for each hammer to be replaced or repositioned or of phases (iv) to (v) if in phases (iii) and (vi) several hammers are unlocked and locked at the same time; (vii) closing the shredder; wherein phases (ii) to (viii) are controlled by a single control unit, which is preferably controlled remotely, and are preferably managed by hydraulic mechanisms, preferably powered by a single hydraulic power unit.

10. The method for changing the hammers of a shredder according to claim 9, wherein the method is automatically managed by a program that performs a maintenance plan identifying the hammers to be replaced or repositioned according to their expected life and their position on the drum.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0057] FIG. 1 illustrates, in a simplified diagram, a preferred embodiment for a system for semi-automatically changing the hammers of a shredder.

DETAILED DESCRIPTION

[0058] A simplified diagram of a preferred embodiment for a system for semi-automatically changing the hammers of a shredder is shown in FIG. 1. The two main mechanical components of the system are the shredder 10 and a crane 12 designed to transport worn hammers from and new hammers to the shredder. The crane 12 consists of an arm 13 articulated in several points 14. Hydraulic cylinders 16 with their stroke (arrow a) carry out the movement of the members of the arm 13 around the joints 14. An end 13a of the arm 13 is equipped with a hook 18 connected to a cable 20 which can be wound/unwound around a roller 22 in order to lower or lift the hook 18. The arm 13 also has a telescopic system 24 allowing an elongation or shortening of the end of the arm 13a. The other end 13b of the crane 12 which also serves as a support point of the arm 13 is rotatable as indicated by the arrow b.

[0059] Passing in the drawing to observe the shredder 10, a housing 26 is noted which consists of several parts, in particular it comprises covers 26a, 26b and 26c which can be lifted during maintenance, for example to change hammers (not shown), with the actuation (movement indicated by the arrows c) of relative hydraulic cylinders 28. Latches 30 serve for the mechanical locking of the covers of the housing 26. They are laterally extracted to then allow the hydraulic cylinders 28 to lift the covers 26a, 26b and 26c or other elements, such as a beam 32 on which the rotors 34 are constrained, which are used to drag the pieces to be shredded. A chute 27 is designed to make the material to be shredded fall inside the shredder 10. The heart of the shredder 10 is the rotating drum 36 carrying hammers (not shown) subject to maintenance.

[0060] The system for changing hammers is further equipped with a pin puller 38 which inserts and extracts the pins on which the hammers of the shredder 10 are inserted so as to release the hammers for their replacement and then constrain them again. The movement of the crane 12 is managed by a first group of proportional/manual type directional control valves 40, while the shredder 10 and the pin puller 38 are controlled by a second group of proportional/manual type directional control valves 42 which in turn are controlled by a relative control system 44 and 46, respectively, each powered by an electrical source 48. Both control systems 44, 46 are connected to a common control unit, such as a programmable logic controller 50 (PLC) which is equipped with a radio receiver 52 suitable to receive commands from a remote control 54. The two groups of directional control valves are of the hydraulic type and are supplied by a common hydraulic control unit 56 comprising a circuit of a hydraulic fluid and relative pumping means.

[0061] The system shown in FIG. 1 may operate as follows: An operator transmits commands with the remote control 54 to the receiver 52 connected to the control unit 50 which, in response to the command received, activates by means of the control systems 44 and 46 the hydraulic cylinders 28 and the pin puller 38 to open the housing 26 of the shredder 10 and unlock the hammers (not shown) from the drum 36 with the extraction of the pin. With a subsequent command, the operator moves the crane 12, rotating it (arrow b) in the correct position over the selected hammer and bending the arm 13 around the joints 14, possibly changing the length of the end 13a and lowering the hook 18 which attaches the hammer. The crane 12 is managed by means of the control unit 50 which acts on the control systems 44 and 46 which in turn actuate the directional valve assemblies 40, 42. Subsequently, the crane 12 removes the hammer from the shredder 10 and places it, for example, in a warehouse (not shown) where it hooks a new hammer and transports it to the vacant position on the drum where it is inserted. If other hammers do not have to be changed in the same manner, the operator no longer intervenes on the crane, which he has moved after the release of the hammer from the shredder but on the pin puller 38 which re-inserts the pin to fix the new hammer on the drum 36. Subsequently, by means of a further command to the control unit 50, rotors 34 and covers 26a, 26b are lowered to close the housing 26, i.e., the shredding chamber. The shredder is now ready to begin shredding scrap or the like.