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GB2076311A - Document shredding machine - Google Patents

Document shredding machine Download PDF

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Publication number
GB2076311A
GB2076311A GB8114361A GB8114361A GB2076311A GB 2076311 A GB2076311 A GB 2076311A GB 8114361 A GB8114361 A GB 8114361A GB 8114361 A GB8114361 A GB 8114361A GB 2076311 A GB2076311 A GB 2076311A
Authority
GB
United Kingdom
Prior art keywords
cutter
assemblies
machine according
machine
cutter assembly
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
GB8114361A
Other versions
GB2076311B (en
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Ofrex Group Ltd
Original Assignee
Ofrex Group Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Ofrex Group Ltd filed Critical Ofrex Group Ltd
Priority to GB8114361A priority Critical patent/GB2076311B/en
Publication of GB2076311A publication Critical patent/GB2076311A/en
Application granted granted Critical
Publication of GB2076311B publication Critical patent/GB2076311B/en
Expired legal-status Critical Current

Links

Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B02CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
    • B02CCRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
    • B02C18/00Disintegrating by knives or other cutting or tearing members which chop material into fragments
    • B02C18/06Disintegrating by knives or other cutting or tearing members which chop material into fragments with rotating knives
    • B02C18/14Disintegrating by knives or other cutting or tearing members which chop material into fragments with rotating knives within horizontal containers
    • B02C18/142Disintegrating by knives or other cutting or tearing members which chop material into fragments with rotating knives within horizontal containers with two or more inter-engaging rotatable cutter assemblies
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B02CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
    • B02CCRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
    • B02C18/00Disintegrating by knives or other cutting or tearing members which chop material into fragments
    • B02C18/0007Disintegrating by knives or other cutting or tearing members which chop material into fragments specially adapted for disintegrating documents
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B02CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
    • B02CCRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
    • B02C18/00Disintegrating by knives or other cutting or tearing members which chop material into fragments
    • B02C18/06Disintegrating by knives or other cutting or tearing members which chop material into fragments with rotating knives
    • B02C18/16Details
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B02CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
    • B02CCRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
    • B02C18/00Disintegrating by knives or other cutting or tearing members which chop material into fragments
    • B02C18/0007Disintegrating by knives or other cutting or tearing members which chop material into fragments specially adapted for disintegrating documents
    • B02C2018/0069Disintegrating by knives or other cutting or tearing members which chop material into fragments specially adapted for disintegrating documents with stripping devices
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B02CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
    • B02CCRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
    • B02C18/00Disintegrating by knives or other cutting or tearing members which chop material into fragments
    • B02C18/06Disintegrating by knives or other cutting or tearing members which chop material into fragments with rotating knives
    • B02C18/16Details
    • B02C2018/164Prevention of jamming and/or overload

Landscapes

  • Engineering & Computer Science (AREA)
  • Food Science & Technology (AREA)
  • Crushing And Pulverization Processes (AREA)

Abstract

The invention concerns a document shredding machine of the kind comprising two cutter assemblies (6, 8), each assembly comprising a drive shaft (10, 18) upon which cutter discs (14, 20) are mounted at spaced intervals, the assemblies (6, 8) being mounted so that the discs (14 or 20) of the other assembly with little or no clearance, the machine comprising a drive motor to rotate the drive shafts (10, 18) in opposite directions. One of the cutter assemblies (6) is fixedly mounted on the machine frame (28) and the other assembly (8) is mounted for movement about a pivot axis (34) between a normal working position and a separated position, determined by the position of a manually- operable device and a stop (38) thereof. In the event that the cutter assemblies jam, by documentary material of considerable thickness being fed into the nip, the manually- operable device may be operated to permit separation between the cutter assemblies, against the action of spring means (36), to permit unblocking of the machine. <IMAGE>

Description

SPECIFICATION Improvements relating to document shredding machines.
This invention is concerned with improvements relating to document shredding machines, particularly of the kind comprising two cutter assemblies, each assembly comprising a drive shaft upon which cutter discs are mounted at spaced intervals, the assemblies being mounted so that the discs of one assembly enter into the gaps between the discs of the other assembly with little or no clearance, the machine comprising drive means to rotate the drive shafts in opposite directions, so that the overlapping discs collectively act to undercut material fed into the nip of the machine into narrow strips. Such machines are hereinafter referred to as being of the kind specified.
In the operation of machines of the kind specified, a common problem is encountered in the shredding of paper. To maximise throughput, it is desirable to feed into the nip several sheets simultaneously, which are all cut into narrow strips. However when too many sheets are fed into the nip simultaneously, the machine will jam.
When this happens, the paper may be pulled away from the nip: however this may be difficult to accomplish, especially where the machine comprises cutting discs, each of which has a plurality of angularly-spaced notches to cut the strips transversely into short lengths. Additionally, this method of unjamming requires the incorporation of safety devices, to render the drive means incapable of operation whilst the machine is being unjammed.
Thus, it has previously been suggested to provide in a machine of the kind specified a reversing means for the drive motor, so that when jamming occurs, the direction of rotation of the cutter discs may be reversed, to eject the jammed material from between the cutter discs. However the use of reversing means adds to the cost of the machine, and under certain circumstances jamming occurs which cannot be removed even by reversing the direction of drive.
According to this invention there is provided a machine of the kind specified.
wherein the cutter assemblies are so mounted as to be capable of limited separative movement.
In this manner, when jamming occurs, the cutter assemblies may be separated, allowing the machine to be unjammed with ease, permitting continued use of the machine Most conveniently one of the cutter assemblies is fixed, and the other is mounted for movement away from said fixed cutter assembly from a normal working position. conveniently being mounted for such movement about a pivot axis.
Conveniently the degree of separation permitted is limited so as to maintain the cutter discs of the two assemblies in said overlapping relationship.
Conveniently the machine comprises a manually operable device to move one of the cutter assemblies or to allow one of the cutter assemblies to move away from the other by a permitted amount: preferably the amount is such as to retain gearing of said one cutter assembly, through which the cutter assembly is driven by the drive means, in engagement with the drive means. In this manner driving of both cutter assemblies may be continued during separation of the cutter assemblies.
Preferably said one cutter assembly is mounted for movement between the normal working position and a retracted position, and is spring-urged into its normal working position, and the manually operable device comprises cam means adapted to urge the said one cutter assembly to its retracted position against the action of said spring, or to allow said one cutter assembly to so move to its retracted position.
Preferably the construction and arrangement is such that, when the jam has been cleared, the said one cutter assembly automatically returns to its advanced position.
There will now be given a detailed description, to be read with reference to the accompanying drawings, of a shredding machine which has been selected for the purposes of illustrating this invention by way of example.
In the accompanying drawings: Figure 1 is a side elevation of the machine which is the preferred embodiment of this invention; Figure 2 is an end elevation, showing the machine in its normal working condition; and Figure 3 is an end elevation, showing the position adopted by one of the cutter assemblies of the machine, when the machine is being unjammed.
The machine which is the preferred embodiment of this invention is specifically a document shredding machine of the kind specified, comprising first and second cutter assemblies 6, 8 respectively. The first cutter assembly comprises a hexagonal drive shaft 10, connected to the output of a drive motor 12, and cutter discs 14 mounted on the shaft 10 at spaced intervals determined by stripper members 1 6. The cutter assembly 8 similarly comprises a drive shaft 18, at spaced intervals determined by stripper members 22.
At an end portion remote from the drive motor 1 2 the shaft 10 is provided with a gear wheel 24 which, during normal operation of the machine, is in meshing engagement with a gear wheel 26 secured to the drive shaft 18. Thus, the drive motor 1 2 is operative to rotate the drive shaft 10 in one direction, and the drive shaft 1 8 in the opposite direction through the gear wheels 24, 26.
The discs of each cutter assembly enter the gaps between the discs of the other cutter assembly, the thickness of the stripper members 1 6 and 22 being such that there is little or no clearance between the discs. Material fed into the nip N between the cooperating cutter discs (Fig. 2) is shredded by the cooperating cutter assemblies into narrow strips, being deposited in a bin (not shown) placed beneath the cooperating cutter assemblies.
The first cutter assembly 6 is secured to a machine frame by tie rods 30, 31 passing through the stripper members 1 6 and through the side plates 29 of the machine frame; in this manner, the first cutter assembly is maintained in fixed relationship relative to the machine frame. The second cutter assembly comprises carrier plates 40, and is secured to the machine frame 28 by a single tie rod 34 which passes through the carrier plates 40, through the stripper plates 22 and through the side plates 28 of the machine frame, and a tie rod 35 which passes through the carrier plates 40, through the stripper plates 22, but not through the side plates 20 (see Fig. 2).
Thus, the second cutter assembly is mounted on the machine frame for pivotal movement about the axis of said tie rod 34.
Extending between part of the first cutter assembly and part of the second cutter assembly is a strong tension spring 36, adapted to urge the second cutter assembly towards the first cutter assembly into a normal working position, determined by engagement of the second cutter assembly with a stop (not shown).
The machine which is the preferred embodiment of this invention comprises a manually operable release device, comprising a shaft 38, which affords a stop of the device, carried by the machine frame and mounted for rotation in bores thereof by a handle 39 (see Figs.
1 and 3). In the normal working condition of the release device, the shaft 38 bears against the carrier plates 40 of the second cutter assembly, preventing movement of said cutter assembly 8 from its normal working condition. However by rotation of the handle 39, the shaft may be rotated, moving a cut-away portion of the shaft into opposition with said carrier plates 40 allowing the carrier plates, and hence the second cutter assembly, to move about the axis of the tie rod 34 against the action of the spring 36 by a small, predetermined increment. The handle 39 of the release device is however urged by a spring (not shown) to adopt a position in which the shaft 38 adopts the position shown in Fig. 2.
During normal running of the machine, documentary material such as paper is fed into the nip, and is shredded in conventional manner. However in the event of documentary material jamming between the cutter discs, the handle 39 may be moved manually to rotate the shaft 38 to the position shown in Fig. 3, allowing the second cutter assembly 8 to move away from the first cutter assembly, opening the nip between the two sets of cutter discs. The degreee of permitted movement of the second cutter assembly (determined by the extent of the reduction of the shaft 38) is insufficient to take the gear wheel 26 out of engagement with the gear wheel 24, and consequently during such movement of the second cutter assembly, the shaft 1 8 thereof continues to rotate, feeding material jammed between the two cutter assemblies through the nip and into the bin.
The separated position adopted by the second cutter assembly 8 is shown in Fig. 3 to be such as to withdraw the cutter discs of the two assemblies from overlapping relationship.
Thus, some material being fed through the nip whilst the second cutter assembly is in its retracted position will not be shredded. However if desired the degree of movement of the second cutter assembly may be limited to an extent, which although sufficient to open the nip slightly, and consequently to allow passage of jammed material through the machine, is insufficient to take the cutter discs from their overlapping relationship. Thus, material which is fed through the nip on operation of the release device, passes into the bin in shredded condition.
Upon completion of unjamming of the machine, the spring 36 urges the second cutter assembly back to its normal operating position, moving the carrier plates from engagement with the shaft 38. The shaft 38 consequently rotates, returning to its normal working position as shown in Fig. 2.
Although the invention has been described hereinabove in relation to a machine comprising a drive motor operative in one direction only, the invention can be used in a machine comprising a motor having a reverse drive facility.

Claims (11)

1. A machine of the kind specified, wherein the cutter assemblies are so mounted as to be capable of limited separative movement.
2. A machine according to Claim 1 wherein one of the cutter assemblies is fixedly mounted on the frame and the other is mounted for limited movement away from the fixed cutter assembly.
3. A machine according to Claim 2 wherein said movable cutter assembly is mounted for movement relative to the fixed cutter assembly about a pivot axis.
4. A machine according to any one of the preceding claims wherein the degree of separation permitted is limited so as to maintain the cutter discs of the two assemblies in said overlapping relationship.
5. A machine according to any one of the preceding claims comprising a manually operable device to move one of the cutter assemblies, or to allow one of the cutter assemblies to move away from the other by a permitted amount.
6. A machine according to any one of the preceding claims wherein the amount of permitted movement is such as to retain gearing of said one cutter assembly in engagement with the drive means.
7. A machine according to any one of the preceding claims wherein the construction and arrangement is such that the drive means continues to operate, to rotate at least one of the shafts, when the cutter assemblies are so separated.
8. A machine according to one of Claims 5 and 6 wherein said manually operative device comprises a stop which may be moved manually between a first position in which it engages the movable cutter assembly to prevent movement thereof from its normal working position and a second position in which movement of the movable cutter assembly may take place.
9. A machine according to any one of the preceding claims comprising means to act on at least one of the cutter assemblies to urge the cutter assemblies towards one another.
10. A machine according to Claim 9 wherein said means is afforded by a tension spring connected to an extending between the cutter assemblies.
11. A machine of the kind specified, constructed and arranged substantially as hereinbefore described with reference to the accompanying drawings.
1 2. Any novel feature or novel combination of features hereinbefore described and/or shown in the accompanying drawings.
GB8114361A 1980-05-27 1981-05-11 Document shredding machine Expired GB2076311B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB8114361A GB2076311B (en) 1980-05-27 1981-05-11 Document shredding machine

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB8017324 1980-05-27
GB8114361A GB2076311B (en) 1980-05-27 1981-05-11 Document shredding machine

Publications (2)

Publication Number Publication Date
GB2076311A true GB2076311A (en) 1981-12-02
GB2076311B GB2076311B (en) 1984-02-22

Family

ID=26275644

Family Applications (1)

Application Number Title Priority Date Filing Date
GB8114361A Expired GB2076311B (en) 1980-05-27 1981-05-11 Document shredding machine

Country Status (1)

Country Link
GB (1) GB2076311B (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1987002911A1 (en) * 1985-11-18 1987-05-21 Umwelttechnik Hatlapa Gmbh Comminution device
GB2254270A (en) * 1991-03-22 1992-10-07 Schleicher & Co Int Shredder.

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1987002911A1 (en) * 1985-11-18 1987-05-21 Umwelttechnik Hatlapa Gmbh Comminution device
GB2254270A (en) * 1991-03-22 1992-10-07 Schleicher & Co Int Shredder.
GB2254270B (en) * 1991-03-22 1995-01-04 Schleicher & Co Int Document shredder

Also Published As

Publication number Publication date
GB2076311B (en) 1984-02-22

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Legal Events

Date Code Title Description
PCNP Patent ceased through non-payment of renewal fee

Effective date: 19940511