GB2065592A - Machine for sheathing articles in an initially flat gusset- folded flexible tube - Google Patents

Abstract

The machine comprises a chassis 1 having a four pillars 2 in which a rectangular frame 10 is vertically slidable. A stack 5 of articles can be located within the chassis by a conveyor 3. The flat-folded tube 6 is fed downwardly by rollers 7 and encounters retractable wedges 9 on opposite sides of the frame 10, the wedges 9 entering the gusset folds to separate their adjacent faces. Four roller clamps 17 each comprise two rollers and are slidably mounted in pairs on opposite sides of the frame 10. The clamps can each be actuated to grip the tube 6 between the two rollers which form the clamp, and the clamps of each pair can be slid apart to spread the tube 6 and to permit its open bottom edges to be gripped by devices 11 which can move downwards on the pillars 2 to draw the tube 6 through the rollers of the clamps 17 and over the stack 5. Before completion of the downward movement of the devices 11 the wedges 9 are withdrawn from the tube path to cause the top end of the tube to be stretched horizontally over the stack 5. The frame 10 and devices 11 then move down in synchronism and the clamps 17 are finally disengaged from the tube 6. <IMAGE>

Description

SPECIFICATION Machine for sheathing articles in an initially flat gusset-folded flexible tube.

The invention relates to a machine for sheathing articles in a flexible tube which is initially flat and gusset-folded.

Such a machine is required to open the tube, to grip the opened tube edges and to draw the tube down over the articles to be sheathed.

Since opposed surfaces of the flat folded tube frequently stick together, drawing the tube downwards over the articles may be difficult.

It is one object of the present invention to provide a machine for the purpose indicated above, in which separation of the tube surfaces is facilitated.

In a known sheathing machine, as disclosed in German patent specification DE OS 25 49 251 the gusset-folded faces of the tube are opened by means of wedges mounted on a vertically-movable frame on the machine, and by means of four roller clamps which maintain the tube wide open as it is pulled downwards by four gripping devices which engage the inside of the open end of the tube.

In this known machine the frame initially moves downwardly in synchronism with the gripping devices. The frame is then stopped and the tube is released from the roller clamps and the wedges, while the gripping devices continue to move downwards. As a result, during the last part of a sheathing operation the tube is sliding across the top of the articles being sheathed, and where a plurality of articles are arranged in a stack, the aforesaid sliding can cause articles to be displaced from the stack.

The present invention provides a sheathing machine of the foregoing general type in which sections of the tube are first stretched between the wedges and the roller clamps, and these tube sections are move downwards to a location adjacent the upper face of an article, or stack of articles, to be sheathed.

In the present invention it is arranged that two wedges on opposite sides of the machine can be moved out of engagement with the tube, and also that the tube can be released from the roller clamps, disengagement of the wedges being effected before release of the tube from the roller clamps. Immediately after disengagement of the wedges the frame carrying the roller clamps is held stationary and the gripping devices are moved downwards, drawing the tube through the clamps and stretching it between them. The frame, and the clamps thereon, then moves downwards in synchronism with the gripping devices until the section of the tube between the roller clamps lies adjacent the upper face of the article or stack to be sheathed. The tube is then released from the rollers of the clamps, and comes into contact with the upper face of the article or stack.In this way it is possible to effect the sheathing operation without scraping contact between the tube and the work being sheathed.

Release of the tube from the roller clamps is preferably effected by mounting one roller in each roller clamp for axial movement horizontally out of the path of the tube.

The movement of the wedges and of the clamp rollers is effected by means of suitable drive means, pneumatic piston-cylinder arrangements are normally used, since such arrangements are easily utilised in tube sheathing machines. Suitable control means are available, which will ensure a correct timing sequence for the wedges and clamp rollers on a machine according to the invention. A machine according to the invention can also be applied in case of the use of a pre-welded, preperforated tube, which is torn from the length of tubing, nevertheless cutting and welding accessories are usefully located above the wedges and beneath a pair of feed rolls.

According to the invention there is provided a machine for sheathing articles in a flexible tube which is initially flat and gusset-folded, said machine comprising a chassis, a frame vertically slidable on said chassis, first and second pairs of roller clamps horizontally slidable on respective sides of said frame, said roller clamps being engageable with the tube walls to spread the latter, gripping means for engaging an open end of said tube, said gripping means being slidable downwardly on said chassis to dravd said tube over an article which is, in use, located below said frame, the machine also including means for parting the gusset folds of said tube, said parting means being movable into and out of the paths of said gusset folds.

In a particular embodiment there are provided four auxiliary clamps mounted for sliding movement with said roller clamps, said auxiliary clamps also being mounted so as to move clear of the tube path in the spread positions of said roller clamps.

In the accompanying drawings: Figure 1 is a side view of a first embodiment of a machine according tO the invention, Figure 2 is a section along ll-ll of Fig. 1, Figures 3-6 are various operational conditions of the machine shown in Fig. 1, Figure 7 is an enlarged scale side view of part of the machine in Fig. 1, Figure 8 is a plan view of the illustration according to Fig. 7, Figure 9 is a section along line IX-IX of Fig. 8, Figure 10 is a front view of an alternative embodiment, having horizontally movable gripping devices, Figure 10 is a front view of a tube coating machine with horizontally extending gripper fingers Figure 11 is a section along ine XI-XI of Fig. 10 Figure 12 is an enlarged view of the horizontally moving gripper.

Figure 13 is a clamp-gripper according to Fog. 12, in a second position Figure 14 is a section along line XIV-XIV of Fig. 12, Figure 15 is a sectio along line XV-XV of Fig. 12, Figure 16 is a rear view o"' the illustration of Fig. 13, and Figure 1 7 is a detail of Fig. 12 with guide- screens.

In the embodiment shown in Figs. 1 to g a sheathing machine has, es indicated in F:gs. 1 and 2, a chassis 1 having four vertical pillars 2 between which lies e conveyor track 3.

Workpieces in the form of pre-arranged stacks of articles 5 are brought along the track 3 on pallets 4 and locats within the chassis 1. A plastics sheet tube 6 is drawn by feed rolls 7 from a stock roll (no- shown) and fed down wards through a cutting and welding unit 8.

The gusset folds of the tube 6 engage wedges 9 which are mounted on a frame 10 which is vertically slidable in the chassis 1.

wedges 9 engage and part the outer surface3 of the gusset folde, these surfaces initially being in contact. The tube 6 subsequently passes downwards and is engaged by roller clamps 1 7.

As shown more clearly in Fig. 2, first and second pairs of roller clamps 17 are slidebly mounted on respective opposite side of the frame 10. As shown in Figs. 7 to 9 each roller clamp 17 is mounted on a respective slide 13 which is in turn mounted in the frame 1 0 for sliding movement by means of a plate 16. Each of the clamps 17 comprises two rollers, and as shown in Fig. 9, one roller 21 in each clamp is mounted on its side 15 by a shaft 18, and is movable towards and away from the element 10 hy means of a piston and cylinder arrangement 22.The other roller in each clamp is mounted on it slide 13 for movement by a piston and cylinder arrangement 19, in a direction parallel to the movement of its slide 1 3, into clamping engagement with the associated roller 21.

As seen in Fig. 7 the two slides 13 on each side of the frame 10 engage respective upper and lower runs of chains carried by sprocket wheels 15, so that the clamps 17 in each pair may be moved apart. The rollers in each clamp are thus relatively movable into and out of clamping engagement, and the clamps in each pair are movable towards and away from each other. At the top of Fig. 2 a pair of the clamps 17 are shown unclamped but in their inner, adjacent positions, while in the lower part of Fig. 2 the clamps are shown in their engaged positions but moved outwardly apart. In Figs. 7 and 8 the clamps 17 are schown disengaged, and with the right hand clamp 1 7 in both its inner and cuter positions.

As shown in Figs. 1, 2, 7, 8 and 9, the wedges 9 are mounted on opposite sides of the frame 10 and are operable by a piston and cylinder arrangements 20, whereby the wedges 9 may be moved horizontally from inward operating positions, as shown in the lower part 0"' Fig. 2 and in Figs. 8 and 9, in which the wedge 9 can engage the gusset fold of a tube, to an outer position as shown in the upper part of Fig. 2, in which the wedge 9 is clear of the @@ path of the tube 6.

Four stud grippers: 1 are mounted on vertical sliders 12 in the respective pillars 2 and the operable to tilt diagonally outwardly to engage within the bottom edge of the open tube 6. Subsequent downward movement of the grippers 11 will then pull tube 6 over the stack 5 and pallet 4.

In use, with the roller clamps 17 open and in their adjacent positions, the tube 6 is fed through the rollers 7 and the gussel folds are parted by the wedges 9, which are in their inner, operative positions. The tube 6 is fed downwards sufficiently far as to be subsequently engageable by the grippers 11. The clamps 17 are then operated by their piston end cylinder devices' 19 to @ engage 3 the tube 6, and the clamps 17 are moved apart, opening up the tube 6 back to the rollers 7. The grippers 11 can then engage the inside of the opened tube. This condition is shown in Fig.

3.

The grippers 11 are then moved downwards on their slides 12, puiling the tube downwards parting lying on the roller clamps 17, the gusset parting lying on the @pices of the wedges 9, this condition being shown in Fig.

4. The wedges are then moved horizontally outwards by their piston and cylinder units 20, to inoperative positions out of the path of the tube. Subsequent downward movement of the grippers 11 stretches the part of the tube 6 immediately above the clamps 17, so that this part of the tube lies substantially parallel to the top of the stack. This tube 6 may previously have been cut and welded by the unit 8. This condition is shown in Fig. 5.

The grippers 11 and the frame 10, with the clamps 17 thersen, are moved downwardly in synchronism to the position shown in Fig. 6, whereupon the clamps 17 are disengaged.

Finally, the rollers 21 (Figs. 7, 8 and 9) of each clamp are pulled hy their piston and cylinder units 22 out of the parth of the tube 6. The clamps 17 thus disengegs completely from the tube 6 which can then drop into close engagement with the stack 5.

The alternative embodiment shown in Figs.

10 to 17 has, as indicated in Figs. 10 and 11, a chassis 101 having pillars 102, a conveyor track 103 for a pallet 104 and a stack 1 05, corresponding to the chassis 1, pillars 2, track 3, pallet 4 and stack 5 described above. A gusset-folded tube 106 cutting unit 108, past wedges 109 on a frame 110, and drawn down by stud grippers 111 on sliders 11 2 on the pillars 102, these elements respectively corresponding to the tube 6, rollers 7, unit 8, wedges 9, frame 10, grippers 11 and sliders 1 2 previously described.

As shown in Figs. 1 2 to 15, combined clamping and gripping devices are mounted for sliding movement on opposite side of the frame 11 0, in a like manner to the roller clamps 1 7 previously described.

The combined clamping and gripping devices are mounted on slides 11 3 which engage lower and upper runs respectively of a chain 114 carried by sprocket wheels 115, the slides 11 3 being mounted on the frame 110 by plates 116. Again these elements correspond to the slides 13, chain 14, wheels 1 5 and plates 1 6 previously described.

The combined clamping and gripping devices include roller clamps 117, Corresponding generally to the clamps 17, and having a fixed roller mounted on a shaft 11 8 and a further roller which is axially movable by piston and cylinder arrangement 11 9. The shaft of each of the innermost, fixed rollers carries a downwardly extending pivot arm 120, at the free end of which is an auxiliary clamp 121. Each of the clamps 121 includes, as shown in Fig. 15, a U-bracket 1 22 of which one arm forms a clamping pad.A clamp element 1 23 is operable by a piston and cylinder arrangement 1 24 mounted on the bracket 1 22. One end of a lever 1 25 is secured to the bracket 1 22 and the free end of the lever 1 25 lies outside the frame 110, that is on a side of the frame member opposite to that on which the tube 106 passes.

The free end of each lever 1 25 co-operates with an associated stop 1 26 (Fig. 16), also on the outside of the frame member. The lever 125 first engages a front face of its stop 126.

As a result, as seen in Fig. 13, the auxiliary clamps 1 21 are pivotted about the shafts 11 8 of the inner, fixed rollers of the clamps 117, as the clamping and gripping arrangements reach the outer ends of their travel. The spaces below the roller clamps 11 7 are thus cleared and the grippers 111 can engage the open edges of the tube 106.

In order to guide the gusset folds into the auxiliary clamps 121 there may be provided guide plates 128, 129, as shown in Fig. 1 7.

Each plate 1 28 is secured to a corresponding tJ-bracket 1 22 and is as wide as that arm of the bracket 1 22 which is engaged by the clamp 1 23. The guide plates 1 29 are secured to the frame 110 se as not to impede movement of the auxiliary clamps 121. The plates 1 28, 1 29 are convergent in the direction of travel of the tube therebetween.

Claims (11)

1. A machine for sheathing articles in an initially flat, gusset-folded, flexible tube, said machine comprising a chassis, a frame vertically slidable on said chassis, first and second pairs of roller clamps horizontally slidable on respective sides of said frame, said roller clamps being engageable with the tube walls to spread the latter, gripping means for engaging an open end of said tube, said gripping means being slidable downwardly on said chassis to draw said tube over an article which is, in use, located below said frame, the machine also including means for parting the gusset folds of said tube, said parting means being movable into and out of the paths of said gusset folds.

2. A machine as claimed in Claim 1 in which said roller clamps each comprises two rollers and means for moving one of said rollers into clamping engagement with the other of said rollers.

3. A machine as claimed in Claim 2 in which one roller in each of said clamps is axially movable out of the path of said tube.

4. A machine as claimed in Claim 1 or Claim 2 which includes four auxiliary clamps mounted for sliding movement with respective ones of said roller clamps.

5. A machine as claimed in Claim 4 in which each said auxiliary clamp is pivotally mounted on a respective roller clamp.

6. A machine as claimed in Claim 4 or Claim 5 in which each auxiliary clamp comprises a U-bracket and a clamp actuator mounted on said bracket.

7. A machine as claimed in Claim 5 or Claim 6 which includes stops engageable by respective ones of said auxiliary clamps in positions thereof adjacent the end of a frame member on which its associated roller clamp is slidable.

8. A machine as claimed in Claim 7 in which each said auxiliary clamp includes a lever for engaging its associated stop, each said stop and said lever being on a side of the frame member opposite to that on which said tube passes, in use.

9. A machine as claimed in any of Claims 4 to 8 which includes guide plates for directing the tube between said roller clamps and said auxiliary clamps.

10. A method of operating a machine as claimed in any preceding claim, comprising engaging the tube in said roller clamps, spreading the open end of said tube by moving apart the roller clamps in each pair thereof, engaging said gripping means with the edge of said open end, moving said gripping means downwardly to draw said tube over an article in said machine, moving said gusset-parting means out of the tube path, moving said roller clamps and said gripping means downwards in synchronism, and disengaging said roller clamps from said tube.

11. A machine for sheathing articles in an initially flat, gusset-folded flexible tube, substantially as hereinbefore described with reference to Figs. 1 to 9 or 10 to 1 7 of the accompanying drawings.