GB1572757A - Tape handling apparatus - Google Patents

Description

(54) IMPROVEMENTS IN OR RELATING TO TAPE HANDLING APPARATUS (71) I, THE SECRETARY OF STATE FOR DEFENCE, Whitehall, London, SW1A 2HB, a British Corporation Sole, do hereby declare this invention to be described in and by the following statement: This invention relates to tape handling apparatus of the type which handles tape with a backing material.

Many continuous filament materials are conveniently supplied in the form of tape which is pre-impregnated with resin and usually rolled for ease of handling. If the tape shows a tendency to stick to itself it is common practice to provide a backing material for the tape which prevents one layer of a roll becoming bonded to its neighbours.

A field in which the use of tapes is increasing is the fabrication of laminated structures consisting of layers of tape. The tape used to build up a laminate consists of fibres running lengthways along the tape bonded together by a resin. For laminates fabricated from such tape the orientation of each layer is critically important to the strength characteristics of the finished material. In recent years research has been conducted into suitable patterns for the arrangement of fibres in a laminate. During research the process of laying down lengths of fibre tape to build up a desired pattern has been carried out by hand.

However, now that large scale production is evolving it is desirable that the process of tape laying be mechanised to improve the efficiency of fabrication.

A major problem which has retarded successful automation of the laying process is the difficulty of cleanly and consistently cutting the tape to length. In the situation where the tape is supplied with backing material, the backing material provides convenient means for transporting the tape through the machine and where the tape is so transported it must be cut without severing the backing material otherwise the driving means is lost.

One cutting technique for tapes supplied with backing material which has been tried employs a single cutting edge and an anvil.

The tape is passed under the cutting edge with the backing material in contact with the anvil. When the desired length has passed between anvil and cutting edge, a cutting blow of limited stroke occurs which cuts or notches the tape leaving the backing material intact. The stroke of the cutting blow may be conveniently limited by stops. This cutting technique has a number of weaknesses. The chopping action of a single cutting edge does not consistently produce a clean cut and as a consequence the tape is not completely severed. If the moving parts or stops are worn an incorrect cutting stroke occurs and the backing strip may be cut. If this happens drive is lost and the machine fails. Regular maintenance is essential to prevent this failure.When used with material of a tacky nature, such as for example carbon fibre preimpregnated tape, the chopping action results in a build-up of deposits on the cutting edge which much reduces the sharpness of the cutting edge, necessitating cleaning after relatively few cuts.

An alternative approach is to part the tape and the backing material so that the tape may be cut separately. One tape cutting machine which adopts this approach employs a roller to separate the tape from the backing material and to keep the backing material clear of the cutting apparatus. A single blade effects the cut with a repetitive sawing action as it traverses the tape. There are a number of problems with this method. Speed may be limited because the tape is severed by a number of small strokes and the tape may not be cut cleanly. It is difficult to guide the tape after cutting and the leading edge of the tape may be prone to jam as the tape is transported.

According to the present invention apparatus for cutting tape supplied with a backing material includes a separating wedge, two cutting edges, driving means arranged to transport tape and backing material past the separating wedge such that the backing material passes to one side of the separating wedge and the tape to the opposite side of the separating wedge and such that the tape passes between the cutting edges, and means for effecting a guillotine action between the cutting edges to cut the tape.

In a preferred embodiment of the present invention the tape driving means includes a driven take-up spool for the backing material.

In a tape cutting apparatus according to the present invention a plurality of separating wedges may be included to part the tape from its backing material. The wedges may be arranged in order of size. This arrangement is particularly useful if the tape is tacky, such as for example, carbon fibre tape. A separating wedge as included in the present invention may have substantially flat surfaces or surfaces shaped to suit a particular tape.

The cutting edges may be mounted close to a separating wedge or at any convenient distance away. Alternatively a fixed cutting edge may be formed as part of a separating wedge.

Guides may be included to prevent the tape or backing material jamming or being mlsrouted.

Tape cutting apparatus in accordance with the present invention is suitable for inclusion in a tape laying machine. A preferred form of tape cutting and laying apparatus includes a roller which lays tape upon a surface and may include a guiding wedge mounted on the opposite side of the cutters from the separat ing wedge such that the backing material pas ses over one side of the guiding wedge and the tape over the opposite side of the guiding wedge, and is laid on the surface by the roller.

The quality of any article which is fabri cated by laying lengths of tape side by side may be dependent upon consistency of tape width. In tape laying apparatus according to the present invention longitudinal cutters may be included to trim the tape to a desired width before laying.

Embodiments of the present invention will now be described by way of example only with reference to the diagrammatic drawings accompanying the Provisional Specification, of which: Fig. 1 shows a tape cutter, Fig. 2 shows an arrangement of cutting edges, Fig. 3 shows an alternative arrangement of a tape cutter, Fig. 4 shows a tape cutting and laying machine for carbon fibre tape.

A separating wedge 10 separates tape 11 from its backing material 12 as it moves in the direction indicated by X in Fig. 1. The backing material passes through a slot in a fixed blade 14 and the tape between the fixed blade 14 and a movable blade 15. When a desired length of tape has passed between the cutting edges of the blades 14 and 15, the movable blade 15 is brought towards fixed blade 14 in a guillotine action to cut tape 11.

Guiding plates 16 and a guiding wedge 17 are included to prevent jamming of the tape as it travels in the direction indicated by X. It will be realised that the backing material 12 is not cut and may be used to drive the tape in the direction X. Means for providing the drive are for convenience not shown in Fig. 1 but may include driving rollers in operative contact with the backing material.

In one possible arrangement of the blades 14 and 15 movement of an actuating rod 20 in the direction indicated by Y in Fig. 2 causes the movable blade 15 to move towards the fixed blade 14 with a guillotine action. The blades are pivotted at 19. A slot 18 allows the backing material to pass through the fixed blade 14. The actuating rod 20 may be a connecting rod between the blade 15 and a piston and cylinder arrangement which may be pneumatically or hydraulically actuated or alternatively electrically actuated by a solenoid.

In an alternative embodiment of a tape cutter according to the present invention a fixed cutting edge 30 is formed as part of a separating and guiding wedge 31 of Fig. 3.

Tape and backing material move past the wedge 31 as described with reference to Fig.

1.

A tape cutter as herein described may be included in a cutting and laying machine for carbon fibre tape as shown for example in Fig. 4. Where parts are the same as Figs. 1 and 2 they have been given common reference numerals.

Carbon fibre tape is supplied with backing material on a roll. A roll of tape is placed in a chamber 21 in which there may be a substantially inert atmosphere of, for example, nitrogen to prevent the tape becoming excessively tacky. When the tape cutting and laying machine is in use, tape and backing material is drawn from the roll and passes a roller 22. A first narrow separating wedge 23 separates the tape 11 from the backing material 12, the tape 11 passing to one side of the wedge 23 and the backing material 12 to the other. Plates 24 are included to guide the tape. The lower plate may be advantageously hinged at 25 to facilitate tape threading. The tape 11 then passes a second separating wedge 10 and blades 14 and 15 as described with reference to Fig. 1, and may be cut to a desired length. The tape 11 is laid by a laying roller 26 onto a surface 27 by relative movement of the surface 27 with respect to the roller 26 in the direction indicated by Z. The laying roller 26 is driven so that the peripheral speed is equal to the linear speed in the direction Z. The uncut backing material 12 passes a tensioning roller 28 to a takeup spool 29 which provides driving means for the tape 11 via the backing material 12. The driving means for the take-up spool 29 includes an adjustable friction clutch arranged such that when the laying roller 26 is not in contact with the surface 27 the primary drive comes from the spool 29.When the machine is laying tape on the surface 27 then the drive comes from the laying roller 26 since the friction due to the pressure of the laying roller 26 and the tack of the resin pre-impregnated tape 11 is greater than the loading set at the take-up spool 29. There are many possible alternative arrangements of the rollers 23, 26 and 28 and take-up spool 29.

It will be seen that if suitable means of moving the surface 27 with respect to the laying roller 26 are provided, layers of tape may be built up in any direction.

All rollers are preferably polytetraflouroethylene (PTFE) and all metallic surfaces in contact with the backing material are advantageously PTFE coated to prevent resin pick up.

Trimming blades (not shown in the Figures) may be included to trim the tape to a desired width before laying. This may be of particular benefit where one length of tape is being laid next to another.

It will be realised that there are many alternative arrangements of the present invention. For example, the moving blade may be unpivotted, effecting the guillotine cutting action by a uniform movement of the blade, which may be operated by a ram.

WHAT I CLAIM IS: 1. Tape cutting apparatus for cutting tape supplied with a backing material including a separating wedge, two cutting edges, driving means arranged to transport tape and backing material past the separating wedge such that the backing material passes to one side of the separating wedge and the tape to the opposite side of the separating wedge and such that the tape passes between the cutting edges, and means for effecting a guillotine action between the cutting edges to cut the tape.

2. Tape cutting apparatus as claimed in claim 1 and including a driven take up spool for the backing material.

3. Tape cutting apparatus as claimed in claim 1 or claim 2 having a plurality of separating wedges.

4. Tape cutting apparatus as claimed in claims 1, 2 or 3 wherein a cutting edge is formed as part of a separating wedge.

5. Tape cutting apparatus as claimed in any one preceding claim and including a guiding wedge mounted on the opposite side of the cutters from the separating wedge such that the backing material passes to one side of the guiding wedge and the tape passes to the opposite side of the guiding wedge.

6. A tape cutting and laying machine including tape cutting apparatus as claimed in any one preceding claim.

7. A tape cutting and laying machine as claimed in claim 6 and including a roller for laying tape upon a surface.

8. Tape cutting apparatus substantially as herein described with reference to Figures 1, 2 and 3 of the drawings.

9. A tape cutting and laying machine substantially as herein described with reference to the drawings.

10. Tape cutting apparatus or a tape cutting and laying machine as claimed in any one preceding claim and including longitudinally disposed cutters for trimming the tape to a desired width.

11. Tape cutting apparatus or a tape cut- ting and laying machine as claimed in any one preceding claim including a roller made of polytetrafluoroethylene (PTFE).

12. Tape cutting apparatus or a tape cutting and laying machine as claimed in any one preceding claim wherein metallic surfaces in contact with the backing material are PTFE coated.

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

Claims (12)

**WARNING** start of CLMS field may overlap end of DESC **. laying roller 26 is driven so that the peripheral speed is equal to the linear speed in the direction Z. The uncut backing material 12 passes a tensioning roller 28 to a takeup spool 29 which provides driving means for the tape 11 via the backing material 12. The driving means for the take-up spool 29 includes an adjustable friction clutch arranged such that when the laying roller 26 is not in contact with the surface 27 the primary drive comes from the spool 29. When the machine is laying tape on the surface 27 then the drive comes from the laying roller 26 since the friction due to the pressure of the laying roller 26 and the tack of the resin pre-impregnated tape 11 is greater than the loading set at the take-up spool 29.There are many possible alternative arrangements of the rollers 23, 26 and 28 and take-up spool 29. It will be seen that if suitable means of moving the surface 27 with respect to the laying roller 26 are provided, layers of tape may be built up in any direction. All rollers are preferably polytetraflouroethylene (PTFE) and all metallic surfaces in contact with the backing material are advantageously PTFE coated to prevent resin pick up. Trimming blades (not shown in the Figures) may be included to trim the tape to a desired width before laying. This may be of particular benefit where one length of tape is being laid next to another. It will be realised that there are many alternative arrangements of the present invention. For example, the moving blade may be unpivotted, effecting the guillotine cutting action by a uniform movement of the blade, which may be operated by a ram. WHAT I CLAIM IS:

1. Tape cutting apparatus for cutting tape supplied with a backing material including a separating wedge, two cutting edges, driving means arranged to transport tape and backing material past the separating wedge such that the backing material passes to one side of the separating wedge and the tape to the opposite side of the separating wedge and such that the tape passes between the cutting edges, and means for effecting a guillotine action between the cutting edges to cut the tape.

2. Tape cutting apparatus as claimed in claim 1 and including a driven take up spool for the backing material.

3. Tape cutting apparatus as claimed in claim 1 or claim 2 having a plurality of separating wedges.

4. Tape cutting apparatus as claimed in claims 1, 2 or 3 wherein a cutting edge is formed as part of a separating wedge.

5. Tape cutting apparatus as claimed in any one preceding claim and including a guiding wedge mounted on the opposite side of the cutters from the separating wedge such that the backing material passes to one side of the guiding wedge and the tape passes to the opposite side of the guiding wedge.

6. A tape cutting and laying machine including tape cutting apparatus as claimed in any one preceding claim.

7. A tape cutting and laying machine as claimed in claim 6 and including a roller for laying tape upon a surface.

8. Tape cutting apparatus substantially as herein described with reference to Figures 1, 2 and 3 of the drawings.

9. A tape cutting and laying machine substantially as herein described with reference to the drawings.

10. Tape cutting apparatus or a tape cutting and laying machine as claimed in any one preceding claim and including longitudinally disposed cutters for trimming the tape to a desired width.

11. Tape cutting apparatus or a tape cut- ting and laying machine as claimed in any one preceding claim including a roller made of polytetrafluoroethylene (PTFE).

12. Tape cutting apparatus or a tape cutting and laying machine as claimed in any one preceding claim wherein metallic surfaces in contact with the backing material are PTFE coated.