GB2092940A - Cut and fold device - Google Patents

Abstract

This invention relates to apparatus that is incorporated in automatic machinery for the feeding, cutting and folding of plastic fabrics used in the manufacture of bags and sacks for agricultural produce. Plastic material sheet is clamped to a travelling chain and cut by means including a carriage with pivoted pawl arms which engage the chain to effect reciprocal movement of the carriage. The sheet is clamped between plates on the carriage and cut by a hot wire cutting head on the ends of arms pivoted to the carriage. The cut piece is fed downwardly to a folding unit including a reciprocal horizontal plate which engages the cut sheet intermediate its ends and feeds the partly folded sheet to the nip of opposed pinch rolls. <IMAGE>

Description

SPECIFICATION Cut and fold device This invention relates to methods and apparatus that is incorporated in automatic machinery for the feeding, cutting and folding of plastic fabrics used in the manufacture of bags and sacks for agricultural produce.

This invention comprises of an apparatus which carries out the following procedure:- the fabric or plastic material having first been fed from the bulk roll or plate by means of pinch rollers, is then gripped by the cloth clamps which transports the material forward in a horizontal plane, at the same time a hot wire is severing the material at a predetermined length.

The material is then fed into another set of rollers and belts, which transports it vertically into the required folding position, where a sensor triggers the pecker bar mechanism, which moves into contact with the material and presents it into pinch rollers and belts at approximately 90. The folded material is then transported to the next manufacturing operation.

The above apparatus is comprised of several componant units and parts, as described below with reference to the accompanying drawings.

Figure 1 cutting transport and folding assembly.

Figure 2 the moving cutter unit.

Figure3fold unit.

The moving cutter unit This unit is mounted on a frame which is part of the main machine. This frame supports four rollers in a horizontal plane, with one roller above the other at each end. The top rollers (i) are sprung loaded and are free to rotate. The two bottom rollers (2) are driven and are connected together by chains (3) and sprocket wheels on both sides or the rollers. Those chains as well as providing the driving power also act as a means of transporting the moving cutter unit (Figure 2), when pawl arms 4 or 5 are engaged.

The moving cutter assembly, consists of carriage (6) on which three guide wheels (7) are mounted on each side. These run on the support rails (8).

The carriage is transported backwards and forwards within the frame and between the two pairs of rollers.

On either side of the carriage are mounted a set of pawl arms 4 & 5 which are pivoted at the rear of this carriage and are linked together by the connecting bar (9).

This bar (9) is of a length that will keep the pawl arm separated so that only one can engage with the chain (3) at anytime. In the centre of the connecting bar (9) is an arm with a spring post anchor, to this spring post is attached one end of a tension spring (10) to the other end of this spring is attached to the spring post collar (11) on the cutter arm (12). On the top end of bar 9 is a cam follower (13) which lifts arm (12) when pawl arm (4) is engaged with chain (3).

The cutting head assembly consists of two round arms (12) which are free to pass through pivot collers (14) that are pivoted on either side and at the rear of carriage 6. On the rear end of arms 12 are stop retaining collers 14Awhich limit forward movement of arms (12).

Over the arm (12) and between collers 14 + 11 is a comparison spring (15) which keeps cutting head assembly in its operating position.

the forward ends of arms (12) are connected by the hot wire cutting head.

This head consists of a cross bar which join arms (12) and on which are carried the cam followers (16) at either end of the cross bar are drop arms (17) to which are connecting the hot wire (18) by an insulated tension spring at one end and a insulated adjusting screw at the other end, this hot wire is connected in series with a suitabse power source.

The air cylinder (19) is connected to an anchor pin on the carriage (6) and the other end to the pawl arm (5) this provides motive power for the pawl arm and the upper material clamp plate (20). The lower clamp plate 20A fixed to the carriage (6) below the material to be transported.

Method of operation of the moving cutter unit Figure 2 The motive power is provided by a continuously rotating chain, direction is obtained by using either top or bottom section of the chain. Pawl arm 5 is engaged for forward movement and pawl arm 4 for return, activated by air cylinder (19) which in turn is activated by the limit switches 21 + 22.

Forward mode Activating limit switch (21) causes Pawl arm 5 to be engaged in the top section of the chain, this action also causes the material to be gripped and the cutter bar to cut the material, the cut material is then fed into roller 1 + 2. The cutter bar is mechanically raised when cam follower (16) rides up cam (23).

Return mode Limit switch 22 activated by carriage 6 causes pawl arm 4 to be engaged in the bottom section. This opens material clamp maintains the height of cutter bar.

Thus competing the cycle.

Fold unit The pecker bar fold assembly consists of a plate that is so formed on its leading edge as to grip without damage any material presented to it.

This plate is mounted either in horizontal side guides or on side arms that pivot at the opposite ends.

The plate or pecker bar No. (24) is moved forward into contact with the material to be folded which it then presents into pinch rolls Nos. 25 + 26 at an angle of aprox. 90". These rollers and belts having gripped the folded material cary it on for further processing.

This mechanism is operated by air cylinder No. 27 that is activated by a limit switch No. 28 that is triggered when the material has reached the point at which folding is required.

Claims (4)

1. A moving hot wire cutting head, and material clamping device, which delivers predetermined lengths of material into the folding section.

2. A clamp device as claimed as in (I), which holds the material to the carriage during its forward travel.

3. A hot wire cutting head as claimed in (I), which severes the material at a predetermined length during its forward travel.

4. A folding device as claimed in (1), which folds the severed lengths and presents it into the pinch rollers.