GB2110146A - A tape cutting device - Google Patents

Abstract

A tape cutting device, or use for example in severing tapes binding the edges of pairs of plaster boards 13, between the pairs, comprises a microswitch 14 which senses absence of the upper surface of pairs of boards 13, closing a circuit to energise the winding 16 of a solenoid causing a plunger 17 of the solenoid to extend a blade 18, to sever tape 10. A retain spring 19 causes the plunger to retract when the winding is de-energised, preventing fouling of the path of the tape and boards and preventing extension of blade 18 if the solenoid should fail. <IMAGE>

Description

SPECIFICATION A tape cutting device This invention relates to a tape cutting device, intended particularly for use in cutting edge tapes used for binding pairs of panels of plaster board together in superposed face to face relationship for storage and transport.

Plaster board is usually produced with a smooth calendered surface on one face, and with a rough unfinished surface of lose fibred sheet material on the other surface, and filled with a compacted refractory material. For storage and transport, in order to protect the calendared surface from impacts and abrasions, the panels are superposed with the calendered surfaces laid flat in contact with each other. The pairs of boards are then secured together using adhesive tape to bind the longitudinal edges, which tape also serves to protect the edges against breakage, and serves to seal the filling at the edges.

In a known device, the pairs of boards are fed, ready stacked, in a steady stream along a conveyor, immediately after having been cut to length from a pair of continuous plaster-board sheets, and tape is continuously applied along each longitudinal edge of the pairs of sheets from two dispensers one on each of the conveyor. A Spring loaded blade is used to sever the tape on each side, the blade being mechanically controlled by a feeder which releases the blade when a gap between adjacent pairs of boards is sensed as being in the correct position for cutting of the tape. Due however to wear of parts, the actuation of knife blade comes out of sequence, and the blade thus may impact repeatedly against the edges of the boards, causing notching, and possibly missing the actual zone of severance.

Moreover the known apparatus is large and cumbersome.

It is an object of this invention to provide a tape cutting device which can be made compact, and will not become inaccurate through wear and misadjustment of parts.

According to the invention, a tape cutting device comprises a tape cutting blade mounted on the plunger of a solenoid, the coil of the solenoid being controlled by a micro switch arranged to sense the occurence of gaps between pairs of boards, the plunger being disposed so that on extension the blade will pass through a feed path of the tape, and the solenoid coil being controlled to extend the plunger when a gap is aligned with the blade.

The solenoid is preferably arranged to positively impingethe blade against the tape in a "fail safe" configuration, when the coil is energised, so that if the coil fails, the plunger will not protrude into the tape path.

A preferred embodiment of the tape cutting machine will now be described by way of example with reference to the accompanying drawing, which is a diagram from above showing a tape cutting machine of the invention in use in binding edges of pairs of plasterboard panels. A similar apparatus is located on each side of a conveyor.

As shown, an edge tape 10 is fed from a tape roll 11 via an applicator roller 12 to the edges of a pair of superposed panels 13. As the panels are moved along the conveyor in the direction of arrow 'A', a microswitch 14 feels the uppersurfaces of the boards, and when a gap between pairs of boards is sensed, the microswitch 14, closes to complete an electric circuit 15 to the winding 16 of a solenoid.

Energisation of coil 16 causes plunger 17 of the solenoid to be extended, causing blade 18 mounted to impact with and sever the portion of tape overlying the gap between the pairs of boards.

A return spring 19 causes the plunger 17 to retract when the micro switch 14 is reopened by contacting a further pair of boards. This provides a positive actuation and retraction of the plunger with a fail safe provision so that if the electrical supply fails, the blade is left retracted and not extended.

1. A tape cutting device comprising a tape cutting blade mounted on the plunger of a solenoid, the coil of the solenoid being controlled by switch means having a sensor arranged to sense the occurence of gaps between pairs of boards, said plunger being disposed so that on extension the blade will passtrhough a feed path of the tape, the solenoid coil being energisable to extend the plungerwhen a gap is aligned with the blade.

2. A device according to claim 7 wherein said solenoid is preferably arranged to positively impinge the blade against the tape only when the coil is energised so that if the coil fails the blade will not foul the tape path.

3. A device according to claim 2 wherein the solenoid is arranged to move the blade laterally when energised into the tape feed path, the plunger remaining unextended, the the coil fails.

4. A device according to claim 1 or 2 wherein a retain spring is arranged to retract a generally horizontally moveable blade, thereby preventing extension of the blade if the coil fails and returning the blade to a non-fouling position if the coil is de-energised.

5. A device according to claim 1 wherein the switch means comprises a micro-swith, and the sensing means a micro-switch "feeler ' located to contact the upper surfaces of pairs of boards, which normally holds the switch open and allows the switch to close thereby energising the solenoid if a board surface is absent from contact with the "feeler".

6. Atape cutting device, substantially asherein before described, with reference to and as illustrated in the accompanying drawings.

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

Claims (6)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION A tape cutting device This invention relates to a tape cutting device, intended particularly for use in cutting edge tapes used for binding pairs of panels of plaster board together in superposed face to face relationship for storage and transport. Plaster board is usually produced with a smooth calendered surface on one face, and with a rough unfinished surface of lose fibred sheet material on the other surface, and filled with a compacted refractory material. For storage and transport, in order to protect the calendared surface from impacts and abrasions, the panels are superposed with the calendered surfaces laid flat in contact with each other. The pairs of boards are then secured together using adhesive tape to bind the longitudinal edges, which tape also serves to protect the edges against breakage, and serves to seal the filling at the edges. In a known device, the pairs of boards are fed, ready stacked, in a steady stream along a conveyor, immediately after having been cut to length from a pair of continuous plaster-board sheets, and tape is continuously applied along each longitudinal edge of the pairs of sheets from two dispensers one on each of the conveyor. A Spring loaded blade is used to sever the tape on each side, the blade being mechanically controlled by a feeder which releases the blade when a gap between adjacent pairs of boards is sensed as being in the correct position for cutting of the tape. Due however to wear of parts, the actuation of knife blade comes out of sequence, and the blade thus may impact repeatedly against the edges of the boards, causing notching, and possibly missing the actual zone of severance. Moreover the known apparatus is large and cumbersome. It is an object of this invention to provide a tape cutting device which can be made compact, and will not become inaccurate through wear and misadjustment of parts. According to the invention, a tape cutting device comprises a tape cutting blade mounted on the plunger of a solenoid, the coil of the solenoid being controlled by a micro switch arranged to sense the occurence of gaps between pairs of boards, the plunger being disposed so that on extension the blade will pass through a feed path of the tape, and the solenoid coil being controlled to extend the plunger when a gap is aligned with the blade. The solenoid is preferably arranged to positively impingethe blade against the tape in a "fail safe" configuration, when the coil is energised, so that if the coil fails, the plunger will not protrude into the tape path. A preferred embodiment of the tape cutting machine will now be described by way of example with reference to the accompanying drawing, which is a diagram from above showing a tape cutting machine of the invention in use in binding edges of pairs of plasterboard panels. A similar apparatus is located on each side of a conveyor. As shown, an edge tape 10 is fed from a tape roll 11 via an applicator roller 12 to the edges of a pair of superposed panels 13. As the panels are moved along the conveyor in the direction of arrow 'A', a microswitch 14 feels the uppersurfaces of the boards, and when a gap between pairs of boards is sensed, the microswitch 14, closes to complete an electric circuit 15 to the winding 16 of a solenoid. Energisation of coil 16 causes plunger 17 of the solenoid to be extended, causing blade 18 mounted to impact with and sever the portion of tape overlying the gap between the pairs of boards. A return spring 19 causes the plunger 17 to retract when the micro switch 14 is reopened by contacting a further pair of boards. This provides a positive actuation and retraction of the plunger with a fail safe provision so that if the electrical supply fails, the blade is left retracted and not extended. CLAIMS

1. A tape cutting device comprising a tape cutting blade mounted on the plunger of a solenoid, the coil of the solenoid being controlled by switch means having a sensor arranged to sense the occurence of gaps between pairs of boards, said plunger being disposed so that on extension the blade will passtrhough a feed path of the tape, the solenoid coil being energisable to extend the plungerwhen a gap is aligned with the blade.

2. A device according to claim 7 wherein said solenoid is preferably arranged to positively impinge the blade against the tape only when the coil is energised so that if the coil fails the blade will not foul the tape path.

3. A device according to claim 2 wherein the solenoid is arranged to move the blade laterally when energised into the tape feed path, the plunger remaining unextended, the the coil fails.

4. A device according to claim 1 or 2 wherein a retain spring is arranged to retract a generally horizontally moveable blade, thereby preventing extension of the blade if the coil fails and returning the blade to a non-fouling position if the coil is de-energised.

5. A device according to claim 1 wherein the switch means comprises a micro-swith, and the sensing means a micro-switch "feeler ' located to contact the upper surfaces of pairs of boards, which normally holds the switch open and allows the switch to close thereby energising the solenoid if a board surface is absent from contact with the "feeler".

6. Atape cutting device, substantially asherein before described, with reference to and as illustrated in the accompanying drawings.