GB2123384A - Spool brake mechanism - Google Patents

Abstract

A brake mechanism for a wire or tape spool (102) has a brake lever (41) which is pressed against the spool by an actuating lever (42) biased by a tension spring (43). The lever (42) is connected to a wire take-up arrangement (28) so that take-up of the wire causes rotation of the lever (42) against spring (43) thus releasing the brake. The wire is now unwound from the spool by the lever (42) being returned by the spring (43) which in turn causes reapplication of the brake lever 41. The brake mechanism may be used in a wire stitcher for binding sets of sheets. <IMAGE>

Description

SPECIFICATION Wire-spool brake mechanism The invention relates to wire-spool brake mechanisms particularly for use in wire stitchers for binding sets or signatures of sheets or documents in which the staples or stitches are formed from a continuous wire wound on a spool from which pieces are cut and formed in the machine.

In the past, in orderto control the supply of wire from the spool as it is consumed by a stitcher, friction devices have been provided which act on the spool.

However, as it is taken-up by the stitcher the wire tends to be unwound from the spool in jerks which can leadtoextensiveamountsofwire being unwound.

Although dancers have been used to take up variations in the length ofwire between the spool and the stitcher, these are not always entirely satisfactory and in any eventtake upa substantial space.

According to the present invention there is provided a wire-spool brake mechanism in which a brake lever acting on the spool is repeatedly released and reapplied during delivery ofthewire respectively in response to take up ofthewireand unwinding the wire from the spool.

With such an arrangementclosercontrol over unwinding ofthe wire from the spool is possible.

In a preferred form, the brake mechanism comprises two pivoted levers, a brake lever adapted to engage the spool and an actuating leveracting on said brake lever underthe influence of a spring to press said brake lever against said spool, said actuating lever being connected to a wire delivery device so that, as the wire is fed, said actuating lever is pivoted against the spring action to release theforce on the brake lever and thus permit rotation ofthe spool, which in turn permits wire to unwind from the spool thus releasing the actuating lever, whereupon the spring urges the actuating leverto reapplyforcetothe brake lever.

Suitably, the actuating lever is connected to one end of a flexible wire guidetube having its other end connected to a wire advancing device, and desirably the brake lever engages the rim of the spool.

From another aspectthe inention provides a wire stitcher, particularly for binding sets or signatures of sheets or documents, in which staples are formed from a continuouswirewound on a spool from which pieces are cut and formed in the machine, said spool having a brake mechanism as described above.

In orderthatthe invention may be more readily understood reference will now be made to the accompanying drawings in which: Figure its a schematic side elevation of a finisher for a photocopier incorporating a stitcher according to the invention.

Figure 2 is a schematic side elevation ofthe wire spool brake mechanism according to the invention for use in the stitcher of Figure 1, and Figure 3 is a side elevation of the wire advancing device of the stitcher of Figure 1.

Referring to Figure 1 there is shown a finisher 70 incorporating a stitcher 1 according to this invention. The finisher is adapted to be arranged at the output of a photocopier represented inthe drawing by the output nip rolls 64,65 thereof. Although particularlywell suited for use with a photocopier, the apparatus generally designated 100 is equally well adapted for use with any number of devices in which cut sheets of material are delivered or compiled in a stack.

The finisher 70 comprises a tray 71 having a base or support surface 72 inclined downwardly in the direction of sheet travel towards a registration corner defined by registration fences 74,75 extending along the lower edge and one side of the tray. Above the upperend ofthe supportsurface is arranged the pair of output feed rolls 64,65 of the photocopier. From the feed rolls 64,65 a sheet is directed by a guide plate 78 towards the tray 71. A corner registration device 79, such as a paddle wheel like that described in US Patent No 3669447, is arranged overthe surface 72 to urge the sheets S into the registration corner to position them to receive a stitch from the apparatus 100.The registration fence 74 is rotatable about an axis 74a so that it maybe retractedforelection of bound sets SS into a collection tray 79. Any suitable ejection mechanism, such as drive rollers, may be employed.

The stitcher 100 may take any suitable form but a preferred form thereof is described and illustrated in ourcopending European Application No 0013164.

Wire is delivered to the stitcher 100 from a spool 102. A mechanism for advancing the wire from the spool 102 to the stitcher head is illustrated in Figure 3. The main wire feed block 20 incorporates a wire diode 21 which grips the wire only against movement in the direction opposite the wire advancing direction, which is from right to left in Figure 3. The wire diode 21 essentially comprises a rollerwhich rolls in contact with the wire in a tapered cavity. Thefeed block 20 is incorporated in a crank 22 pivoted at its lower end 23 totheframe 24 of the stitcher. The crank has a slot 25 at its other end engaged by a pin 26 on drive plate 27, rotation of which oscillates the crank 22 about pivot 23. The block 20 is aligned between a flexible wire guide tube 28 extending from the wire spool and a rigid wire guide tube 29 leading to the stitcher head.To advance the wire,the drive plate 27 is driven through a single revolution by a drive motor mounted on the back of bracket 30, the motor being controlled by a microswitch 31. The wire is advanced during the first half revolution ofthe plate 27 and as the crank returns, the wire is gripped against return movement bythe diode 21. For adjusting the size of the staple, in particularthe lengths ofthe staple legs, in proportion to the thickness of the set being stapled, a secondary or proportional wire feed mechanism (not shown) may be provided as described in our aforesaid copending European Application No 0013164.

Referring nowto Figure 2, the wire spool brake mechanism comprises two pivoted levers 41 and 42.

The lever 41 is a brake lever adapted to engage the peripheral edge or rim ofthe spool 102 and act as a brake therefore. The second lever 42 is an actuating lever arranged to act on the brake lever 41 underthe influence of a tension spring 43 to press the brake lever against the spool. The tension spring 43 is connected between lever 42 and a bracket 50 on which axles 44,45 are mounted. The lever 41 is pivoted at one end on an axle 44 and the actuating lever 42 is pivoted intermediate its ends on anaxle45. The brake lever 41 is cranked and arranged so that its elbow 46 engages the rim of the spool.The end 47 ofthe lever 42 engages the free end 48 ofthe lever 41 The other end 49 ofthe lever 42 is attached to the other end ofthe flexible wire guide tube 28 extending from the feed block 20 of the wire advancing device.

In the position shown in Figure 2, the brake lever 41 is pressed againstthe rim of the spool 102 by the spring-pressed lever 42. When the wire advancing device is actuated to advance the wire W, the spool 201 being restrained against rotation, the lever 42 is pivoted anticlockwise against the action of spring 43.

This releases the force on the brake lever 41 and thus permits rotation of the spool 102 so that the wire is unwound by the lever 42 (which has the end of guide tube 28 attached to it) being acted upon the spring 43.

As a resultthe actuating lever 42 reapplies force to the brake lever41 and the brake is re-engaged.

The amount of movement ofthe end 49 ofthe actuating lever42which is required to release the brake may be set as desired by suitable construction of the device and by means of an adjustment mechanism 51 ofthe end ofthe wire guide tube 28.

During movement of the lever 42 variations in distance between it and the feed block 20 are accommodated bytheflexibility of the wire guide tube 28.

Preferably, the brake lever 41 is wide enough to engage both rims of the spool.

Although a specific embodiment of the invention has been described it will be understood that various modifications may be made to the specific details referred to herein with departing from the scope of the invention as described in the appended claims.

Thus, it will be understood that while primarily intended for use in controlling the release of wire from a spool, the invention is equally applicable to other elongated materialseitherinstriporfilamentform, such as adhesive binding tape, and the term 'wire' used herein and in the claims is intended to include such other filament and strip materials.

Claims (6)

1. Awire-spool brake mechanism in which a brake lever acting on the spool is repeatedly released and reapplied during delivery of the wire, respectively in response to take up ofthe wire and unwinding of wire from spool.

2. Awire-spool brake mechanism comprising two pivoted levers, a brake lever adapted to engage the spool and an actuating lever acting on said brake lever underthe influence of a spring to press said brake lever against said spool, said actuating lever being connected to a wire delivery device so that, as the wire is fed, said actuating lever is pivoted againstthe spring action to release the force on the brake lever and thus permit rotation ofthe spool, which in turn permits wire to unwind from the spool thus releasing the actuating lever whereupon the spring urges the actuating lever to reapply force to the brake.

3. Awire-spool brake mechanism according to claim 2, in which actuating lever is connected to one end of a flexible wire guide tube having its other end connected to a wire advancing device.

4. Awire spool mechanism according to claim 2 or 3 inwhichthe brake lever engages the rim ofthespool.

5. Awirespool brake mechanism constructed arranged and adapted to operate substantially as hereinbefore described with reference to the accompanying drawings.

6. Awire stitcher, particularly for binding sets or signatures of sheets of documents, in which staples are formed from a continuous wirewound on a spool from which pieces are cut and formed in the machine, including a wire-spool brake mechanism according to any preceding claim.