GB2280818A - Rotary drum scanner - Google Patents

Rotary drum scanner Download PDF

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Publication number
GB2280818A
GB2280818A GB9415976A GB9415976A GB2280818A GB 2280818 A GB2280818 A GB 2280818A GB 9415976 A GB9415976 A GB 9415976A GB 9415976 A GB9415976 A GB 9415976A GB 2280818 A GB2280818 A GB 2280818A
Authority
GB
United Kingdom
Prior art keywords
drum
hub
scanner
bolt
rotary drum
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
GB9415976A
Other versions
GB9415976D0 (en
GB2280818B (en
Inventor
Peter John Neilson
Paul Christopher Cook
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.)
Itek Colour Graphics Ltd
Original Assignee
Itek Colour Graphics 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
Priority to GB9316355A priority Critical patent/GB9316355D0/en
Application filed by Itek Colour Graphics Ltd filed Critical Itek Colour Graphics Ltd
Priority to GB9415976A priority patent/GB2280818B/en
Publication of GB9415976D0 publication Critical patent/GB9415976D0/en
Publication of GB2280818A publication Critical patent/GB2280818A/en
Application granted granted Critical
Publication of GB2280818B publication Critical patent/GB2280818B/en
Anticipated expiration legal-status Critical
Application status is Expired - Fee Related legal-status Critical

Links

Classifications

    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04NPICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/04Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa
    • H04N1/06Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa using cylindrical picture-bearing surfaces, i.e. scanning a main-scanning line substantially perpendicular to the axis and lying in a curved cylindrical surface

Abstract

A rotary drum scanner comprises a rotably mounted hub 3, and a drum 1 detachably mounted to the hub. An interlock mechanism including a radial mechanism including a radial bolt (Fig 2, 20) carrying a locking pin 26 locks the hub to a fixed point 4 to prevent rotation until the drum is locked to the hub. A button 38 is provided to unlock the drum. A bayonet fitting comprising lugs 10a, 10b, 10c and corresponding recesses 35a, 35b, 35c connects the drum in the hub. <IMAGE>

Description

ROTARY DRUM SCANNER This invention relates to a rotary drum scanner for use in a graphic reproduction process.

Modern methods of producing posters and other graphic works require that a film transparency is electronically scanned and the information contained therein stored in digital form. One type of scanner comprises a transparent drum upon which the transparency is mounted and which is then rotated at high speed. A reading head is then moved linearly with respect to the rotating drum to capture the information in the transparency. The drum is detachably mounted to a rotatable hub and this invention is particularly concerned with a safety mechanism for use in attaching the drum to the hub.

This invention provides a rotary drum scanner comprising a rotatably mounted hub, a drum detachably mounted to the hub and an interlock mechanism which locks the hub to prevent rotation until the mechanism locks the drum to the hub.

Because of the interlock mechanism the hub cannot rotate unless the drum is locked to the hub. This therefore prevents the possibility of an operator accidentally switching on the motor, or other means, for rotating the hub before the drum is locked in position. Electrical interlock arrangements which inhibit the motor until a lid within the scanner casing has been closed have been proposed, but such arrangements are not always reliable.

Preferably attachment of the drum to the hub is operative to cause the interlock mechanism to lock the drum to the hub and to free the hub for rotation.

Preferably the interlock mechanism includes a radially movable bolt carried by the hub which in one condition engages a fixed part of the scanner to prevent rotation of the hub and in another condition engages a part of the drum.

In order that the invention may be well understood an embodiment thereof will now be described by way of example with reference to the accompanying diagrammatic drawings, in which; Figure 1 is a partially cutaway perspective exploded view of part of a scanner according to the invention; Figure 2 is an exploded perspective view of the rotatable hub of the scanner shown in Figure 1; Figure 3 is a cross section through the interlock mechanism shown in Figures 1 and 2 with the drum detached; Figure 4 is the same as Figure 3, but with the drum at a preliminary stage of attachment; and Figure 5 is the same as Figure 4, but with the drum at a final stage of attachment.

As shown in Figure 1 a rotary drum scanner includes a cylindrical transparent dmm 1 attached at its base to a mounting ring 2 by which the drum is detachably mounted, by means of a bayonet type coupling, to a hub 3. The hub 3 is rotatably mounted within a fixed sleeve and bearing assembly 4.

As best seen in Figure 2 the hub 3 is of generally cylindrical shape having an outwardly extensive flange 5 spaced a short distance from one end. A radially extensive bore 6 is formed within the flange 5. Through slots 7, 8 within each face of the flange communicate with the bore 6. The end portion 3a of the hub 3 beyond the flange 5 carries an annular ring 9 which includes three circumferentially equispaced generally L shaped lugs 10a, b, c. The head 11 of each lug includes an underlying face 12 which is tapered with respect to the opposing face of the flange 5. The ring 9 is resiliently biased against the flange 5 by means of a wavy spring washer 13, a flat washer 14 and a circlip 15 retained within a groove 16 formed in the end portion 3a.

A bolt 20 comprises an elongate plunger 21 located within the bore 6 which is biassed outwardly by means of a compression spring 22. The spring 22 rests against the blind end 23 of the bore (best seen in Figures 3 to 5). The plunger 21 includes an indented flat land or recess 25 and a pin 26 which is located in a through hole 27 within the land 25. The pin 26 includes a head 28 which protrudes through the upper most slot 7 and a tip 29 which protrudes through the lower most slot 8.

In the absence of the drum ring 2, and as best seen in Figures 1 and 3, the compression spring 22 urges the radially inner most shoulder 30 between the land 25 and the plunger 21 against a lug 31 which projects downwardly through the slot 7 from the underside of the ring 9. The lug 31 is itself urged into engagement due to the resilience of the spring washer 13 and in this way the pin tip 29 is retained within a radially extensive U shaped slot 32 (Figure 1) provided in the upper most surface of the fixed sleeve 4 underlying the flange 5. The hub 3 is thereby locked to the fixed sleeve 4.

The drum ring 2 includes an internal inwardly extensive flange 34 which is provided with three circumferentially equispaced cut-outs or recesses 35a, b, c corresponding to the three lugs 1 Oa, b, c respectively. A further arcuate cut-out 36 in the flange 34 includes a first region 36a within which the head 26 of the pin is designed to be located when the ring 2 and hub 3 are initially brought together. From there, the edge of the flange slopes radially inwardly to define a wedging surface 36b.

A further recess 36c, deeper in a radial direction than 36a, is provided beyond the wedging surface 36b. A further recess 36d is provided beyond recess 36c and includes a radially extensive side wall 36e, the reason for which will be mentioned later on. The drum ring 2 further includes a through hole 37 communicating with the interior of the deep recess 36c. A radially movable button 38 is retained within the hole 37 and includes a recess 39 in one side to engage the pin head 26. A lug 40 is provided in the uppermost surface of the flange 5 to co-operate with recess 36d.

In use, in the absence of the drum, the hub 3 is in the locked condition described above with reference to Figure 3. The drum is placed upon the hub with the lugs 1 Oa, b, c engaged within their respective recesses 35a, b, c. Whilst the hub is held in the locked condition the drum is rotated in the direction of arrow 41 such that the wedge shaped surface 12 of each lug 10 engages the flange 34 pulling the ring 9 upwardly against the bias of the ring washer 13 and lifting the lug 31 clear of the plunger 21. At the same time, the wedging surface 36b urges the pin head 28 radially inwardly against the bias of the spring 22. Accordingly, as shown in Figure 4, the hub remains locked in position. Continued rotation causes the pin head 28 to enter the cutout 39 in the button 38 whereupon the plunger 21 is urged outwardly so that the pin tip 29 clears the U-shaped slot 32.At the same time the lug 40 provided in the upper most surface of the flange moves along the recess 36d and contacts the wall 36e. During this drum locking procedure, the reaction force tends to force the pin head 28 against the underside of the flange 34. The resulting frictional forces means that the bolt 20 is not released into the recess 36c until the user releases the drum.

The drum 1 is now locked to the hub 3, which is free to rotate.

If the bolt 20 were only held in place by the lug 31 on the ring 9, high surface stresses would be experienced on the plunger edge 30 just prior to release. In addition, the top of the plunger would tend to scrape the base of the lug 31 resulting in a slower less positive change from hub lock to rotating drum lock mode.

In order to remove the drum, the button 38 is depressed and the drum rotated slightly until the pin tip 29 aligns with the U-shaped slot 32. Further pressure on the button 38 then moves the bolt 20 radially inwards. Rotation in the opposite direction to that of arrow 41 lowers the ring 9 and lug 31 into engagement with the shoulder 30 so that the bolt 20 is retained within the bore 6. Continued rotation causes the pin head 28 to enter the recess 36a and for the lugs 10a, b, c to be located in their respective cutouts 35a, b, c. The drum is then free to be removed.

Claims (12)

1. A rotary drum scanner comprising a rotatably mounted hub (3), a drum (1) detachably mounted to the hub (3) and an interlock mechanism (6, 20, 32, 36) which locks the hub against rotation until the mechanism locks the drum (1) to the hub (3).
2. A rotary drum scanner, according to claim 1, in which attachment of the drum (1) to the hub (3) is operative to cause the interlock mechanism (6, 20, 32, 36) to lock the drum to the hub and to free the hub for rotation.
3. A rotary drum scanner, according to claim 1 or 2, in which complementary bayonet coupling parts (10, 35) are provided on the drum (1) and on the hub (3) respectively.
4. A rotary drnm scanner, according to any preceding claim, in which the interlock mechanism includes a radially movable bolt (20) which is carried by the hub (3) and which in one position engages a fixed part (32) of the scanner to prevent rotation of the hub and in another position engages a part (36c) of the drum (1).
5. A rotary drum scanner, according to claim 4, in which the hub (3) carries an axially movable ring (9) which includes bayonet coupling parts (10) and a part (31) which engages the bolt (20) in the absence of the drum (1) to lock the hub (3) to a fixed part (32) of the scanner.
6. A rotary drum scanner, according to claim 4, in which the bolt (20) includes a radially extensive portion (21) and surfaces (26, 29) disposed above and below the radial portion (21) which engage the fixed part (32) of the scanner and the drum (1) respectively.
7. A rotary drum scanner, according to claim 6, in which the hub (3) includes a flange (5) and is mounted for rotation within a fixed sleeve (4) including a planar surface parallel to and adjacent the flange, the bolt (20) being operative to engage a formation (32) within the planar surface to lock the hub against rotation.
8. A rotary drum scanner, according to claim 5, in which the drum (1) includes an internal inwardly extending flange (34) which includes cutouts (35) to receive upstanding lugs (10) formed on the axially movable ring (9), and a further cutout (36) which engages the bolt (20) and allows the bolt (20) to move out of engagement with the fixed part (32) of the scanner as the drum (1) is mounted by rotating it with respect to the hub (3).
9. A rotary drum scanner, according to claim 8, in which the bolt (20) is resiliently biassed outwardly into engagement with the part (31) on the axially movable ring (9), partial attachment of the drum (1) to the hub (3) being operative to move the ring (9) out of engagement with the bolt (20) and into engagement with the further cutout (36) on the drum flange.
10. A rotary drum scanner, according to claim 9, in which the further cutout (36) includes a surface (36b) which holds the bolt in engagement with the fixed part of the scanner after the axially movable ring (9) has been moved out of engagement with the bolt, before allowing the bolt (20) to move out of engagement with the fixed part (32) of the scanner and into locked engagement with the drum.
11. A rotary drum scanner according to claim 10 (1) in which the drum carries a radially movable button (38) engageable with the bolt.
12. A rotary drum scanner substantially as described with reference to the drawings.
GB9415976A 1993-08-06 1994-08-08 Rotary drum scanner Expired - Fee Related GB2280818B (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
GB9316355A GB9316355D0 (en) 1993-08-06 1993-08-06 Rotary drum scanner
GB9415976A GB2280818B (en) 1993-08-06 1994-08-08 Rotary drum scanner

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB9415976A GB2280818B (en) 1993-08-06 1994-08-08 Rotary drum scanner

Publications (3)

Publication Number Publication Date
GB9415976D0 GB9415976D0 (en) 1994-09-28
GB2280818A true GB2280818A (en) 1995-02-08
GB2280818B GB2280818B (en) 1998-01-07

Family

ID=26303344

Family Applications (1)

Application Number Title Priority Date Filing Date
GB9415976A Expired - Fee Related GB2280818B (en) 1993-08-06 1994-08-08 Rotary drum scanner

Country Status (1)

Country Link
GB (1) GB2280818B (en)

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB677040A (en) * 1949-10-19 1952-08-06 Standard Telephones Cables Ltd Facsimile transmitters
GB742412A (en) * 1953-05-15 1955-12-30 Nat Res Dev Device for securing the angular alignment of relatively rotatable bodies
US4902156A (en) * 1987-02-21 1990-02-20 Dipl. Ing. Rudolf Hell Gmbh Mounting device for image cylinders

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB677040A (en) * 1949-10-19 1952-08-06 Standard Telephones Cables Ltd Facsimile transmitters
GB742412A (en) * 1953-05-15 1955-12-30 Nat Res Dev Device for securing the angular alignment of relatively rotatable bodies
US4902156A (en) * 1987-02-21 1990-02-20 Dipl. Ing. Rudolf Hell Gmbh Mounting device for image cylinders

Also Published As

Publication number Publication date
GB9415976D0 (en) 1994-09-28
GB2280818B (en) 1998-01-07

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Legal Events

Date Code Title Description
732E Amendments to the register in respect of changes of name or changes affecting rights (sect. 32/1977)
PCNP Patent ceased through non-payment of renewal fee

Effective date: 20030808

728V Application for restoration filed (sect. 28/1977)
732E Amendments to the register in respect of changes of name or changes affecting rights (sect. 32/1977)
732E Amendments to the register in respect of changes of name or changes affecting rights (sect. 32/1977)
728Y Application for restoration allowed (sect. 28/1977)
PCNP Patent ceased through non-payment of renewal fee

Effective date: 20070808