GB2271095A

GB2271095A - Apparatus for transporting weldable workpieces.

Info

Publication number: GB2271095A
Application number: GB9318416A
Authority: GB
Inventors: Edward Philip Bacon; Stephen Woodthorpe Clarke
Original assignee: CAIRWAY Ltd
Current assignee: CAIRWAY Ltd
Priority date: 1992-09-07
Filing date: 1993-09-06
Publication date: 1994-04-06
Also published as: GB9218877D0; GB9318416D0

Abstract

The invention relates to an apparatus 1 for automatically securing superposed weldable workpieces together, in the embodiment folded over and superimposed parts 2 and 3 of a blank 4 of plastic material such as fluted plastic board or sheet. To effect securing of the superimposed parts so as to provide a blank which can then be assembled to provide a box for produce such as a box for transporting fish as air freight, the apparatus 1 comprises a worksurface 5, a loading station 6 for loading superposed workpieces onto the worksurface, first transport means for transporting the workpieces to a work station 8 having welding head 13 for securing the superposed workpieces together, and second transport means 9 for transporting the secured workpieces to a discharge station 8'. <IMAGE>

Description

APPARATUS FOR WELDABLE MATERIAL The invention relates to apparatus for securing weldable workpieces together, particularly plastic material which is formed of spaced surfaces interconnected by substantially parallel walls extending transversely thereto, to form a "fluted" or cardboard-like structure.

Such material is often used to provide cartons, boxes or the like in which a sheet of the material is converted into a blank of a desired shape, parts of the blank then being folded about crease lines to overlie another part of the blank, the two superposed parts then being secured together to form a blank erectable to a required shape of container without further securing being necessary.

Although such material has been secured to itself before, there has been no automatic or volume production thereof.

It is accordingly an object of the invention to seek to mitigate this disadvantage.

According to the invention there is provided apparatus for automatically securing superposed weldable workpieces together, comprising a worksurface, a loading station for loading superposed workpieces onto the worksurface, first transport means for transporting the workpieces to a work station from the loading station, securing means at the work station for securing the superposed workpieces together, and second transport means for transporting the secured workpieces to a discharge station.

The worksurface may comprise a plurality of substantially parallel spaced apart support bars, and the first and second transport means may be adapted to protrude above the plane of the worksurface for transporting the workpieces.

This provides an obstruction-free return run.

The first and second transport means may be mounted on a carriage which is movable in relation to the worksurface. This provides a relatively simple construction.

The carriage may be below the worksurface and may be longitudinally reciprocable in relation thereto This again provides for relatively simple construction.

The first transport means may comprise jaw means. This provides a positive grip on a workpiece.

The jaw means may be pivotably mounted on the carriage whereby to pivot below the plane of the worksurface at the work station and to raise at least thereunto for gripping workpieces at the loading station. This again provides for an unobstructed operation.

The second transport means may comprise pusher bar means which are reciprocable transversely to the plane of the worksurface whereby in one operative position they are below the worksurface and in a second operative position they project sufficiently to push the workpieces to the discharge station.

This provides for positive operation, and an unobstructed return run.

The securing means may comprise a welding head, suitably a plurality of welding heads, each comprising two ultrasonic welding head devices. This provides for a positive welding of two or more superposed workpieces.

There may be four welding heads arranged orthogonally whereby to provide four welding zones. This provides for welding in a square formation.

Each welding head device may comprise a cylindrical rod with a frusto-conical welding tip.

The welding heads may comprise means for cooling the welding head devices and/or a weld formed between the workpieces. This is a particularly efficacious construction, particularly where the cooling means comprises a jet directed towards the welding head devices and connected with a source of air. The air can be expelled as a jet directed onto the welding tip and weld to cool both simultaneously.

The welding heads may be mounted on support means whereby the relative spatial disposition of the welding heads are adjustable in the apparatus. This provides for welding of blanks of varying dimension.

The worksurface may include guide rails spaced above the worksurface whereby to maintain desired relative positions of the workpieces during transport and welding.

The gripping pressure of the jaw means may be adjustable. This provides for gripping workpieces of differing thickness.

The apparatus may include electronic control means for operating the respective transport means and securing means; suitably the electronic control means may comprise timer means.

Apparatus embodying the invention is hereinafter described, by way of example, with reference to the accompanying drawings.

Fig. 1 is a perpsective view of apparatus according to the invention for ultrasonic welding of superposed plastic sheets; Fig.2 is an enlarged detail of the apparatus of Fig.1; Fig.3 shows a perspective part of a worksurface of the apparatus of Figs. 1 and 2; Fig.4 shows a side elevational view of the worksurface of Fig.3; Fig.5 shows a detail of transporters for workpieces in the apparatus of Figs. 1 and 2; Fig.6 is an enlarged side elevational view from one end of a welding means of the apparatus of Figs. 1 and 2; Fig.7 is a yet further enlarged side elevational view of the welding means of Fig.6, from the other end;; Fig.8 is a schematic side elevational view of a welding head means of the welding means of Figs. 6 and 7, showing how superposed layers of fluted plastic material workpieces are secured together by ultrasonic welding in the apparatus of Figs. 1 to 7; Fig.9 shows schematically a side view of successive operating steps in the apparatus of Figs. 1 to 7; and Fig.10 shows schematically a plan view of the progress of superposed workpieces through the apparatus of Figs 1 to 7.

Referring to the drawings, there is shown apparatus 1 for automatically securing superposed weldable workpieces together, in the embodiment folded over and superimposed parts 2 and 3 (Fig.8) of a blank 4 of plastic material such as fluted plastic board or sheet. To effect securing of the superimposed parts so as to provide a blank which can then be assembled to provide a box for produce such as a box for transporting fish as air freight, the apparatus 1 comprises a worksurface 5, a loading station 6 for loading superposed workpieces onto the worksurface, first transport means 7 for transporting the workpieces to a work station 8 for securing the superposed workpieces together, and second transport means 9 for transporting the secured workpieces to a discharge station 8'.

The apparatus 1 comprises a free standing machine in which the worksurface is an upper surface as viewed defined by spaced apart substantially parallel bars 10, from which surface projects a substantially rectangular frame 11 having crosspieces or transoms 12 from which are supported securing means 12, which comprises four ultrasonic welding heads mounted on carriers which are adjustable in position vertically as by complementary means such as having Tshaped brackets locating in T-section guide slots of the transoms, which are themselves adjustable longitudinally of the machine by being movably mounted by suitable complementary adjustable mounting means positionable longitudinally of the longitudinal bars. The ultrasonic welding heads are thus virtually infinitely adjustable to provide any required spacing of welds depending on the weld spacing required. Each welding head comprises two welding head devices 13 which are cylindrical and have frusto-conical tips 14. In the embodiment the diameter of each device is 14mm, the height of the frusto-cone is 6mm and the diameter of the tip is 8mm.

The two devices 13 depend from the mounting means in parallel, and the welding heads have associated with them cooling means in the form of a jet 15 connected to a source (not shown) of air under pressure, the jet 15 being angled to direct in use a jet of cooling air onto the tip 14 after a welding stage, and onto the weld 16 itself so that both the tip 14 and weld 16 are cooled.

Below the worksurface 5 there is a reciprocable carriage (not shown) on which is mounted the first and second transport means, respectively in the form of a gripper jaw 17 and a pusher bar 9. The gripper jaw 17 is pivotably mounted on the carriage so that it can be rotated below the plane of the worksurface and to a position at least thereonto and in which a part of the jaw means protrudes thereabove so that workpieces can be gripped. The pusher bar 9 is mounted, as by a solenoid operated piston and cylinder arrangement so that the pusher bar can be retracted below the plane of the worksurface 5, and so that it can in another position protrude above the worksurface for pushing welded workpieces 4 to the discharge station 8'.The carriage is reciprocable by chain and sprocket drives and the whole operation of the apparatus is controlled by electronic means utilising suitable sensors, circuitry, etc.

The upper surface (as viewed) of the worksurface also includes spaced guide bars 19 extending longitudinally of the worksurface 5 above the plane thereof to provide a gap within which the workpieces 4 slide.

It will be understood that the apparatus 1 has a plurality of carriages lying sideby-side, so that a plurality of workpieces can be welded simultaneously, automatically.

In use to weld overlapping parts 2, 3 of a blank 4 of fluted plastic material together ultrasonically, the converted blank 4 is placed in the apparatus 1 at the loading station 6, the carriage being at that end with the pusher bars retracted and the gripper means 7 or jaws open, above the plane of the worksurface 5.

Sensors sense the presence of the blank 4, and the jaws 17 clamp to grip the blank 4. A motor is then actuated to draw the blank 4 over the worksurface to a position below the (raised) welding heads 12 at the station 8, which heads are adjusted in position to provide required welding zones for example orthogonally arranged zones as shown at 'X' in Fig. 10. The carriage stops, the welding heads 13 are lowered, by suitable motors, actuated to provide welding ultrasonically at the four zones, and raised, when the air source is actuated to provide a jet of air at 15 which cools the tips 12 and the welds 16.The carriage motor is then actuated after a desired time to draw the blank 4 now welded to the discharge station 8' at the end of the apparatus 1 opposite the loading station 6, where sensors actuate the gripper jaws 17 to pivot them below the plane of the worksurface 5 for the return run to the loading station and the pusher bars 9 are raised to push the welded blank to the discharge station before they are lowered for the return run. Thus blanks can be automatically welded and passed in sequence through the apparatus.

During welding, the welding tips 14 progressively melt the upper part 2 of the blank so that the fused plastic forms a smooth depression terminating at the lower surface of the lower part 3 of the blank 4, the welding process being such that there is a smooth and gradual melting to provide a firm weld, as shown in Fig.8 where the weld side wall 20 is inclined over a large surface area, so providing the firm weld referred to.

Claims

1. . Apparatus for automatically securing superposed weldable workpieces together, comprising a worksurface, a loading station for loading superposed workpieces onto the worksurface, first transport means for transporting the workpieces to a work station from the loading station, securing means at the work station for securing the superposed workpieces together, and second transport means for transporting the secured workpieces to a discharge station.

2. Apparatus according to Claim 1, the worksurface comprising a plurality of substantially parallel spaced apart support bars, the first and second transport means being adapted to protrude above the plane of the worksurface for transporting the workpieces.

3. Apparatus acording to Claim 2, the first and second transport means being mounted on a carriage which is movable in relation to the worksurface.

4. Apparatus according to Claim 3, the carriage being below the worksurface and being longitudinally reciprocable in relation thereto.

5. Apparatus according to Claim 3 or Claim 4, the first transport means comprising jaw means.

6. Apparatus according to Claim 6, the jaw means being pivotably mounted on the carriage whereby to pivot below the plane of the worksurface at the work station and to raise at least thereunto for gripping workpieces at the loading station.

7. Apparatus according to any of Claims 3 to 6, the second transport means comprising pusher bar means which are reciprocable transversely to the plane of the worksurface whereby in one operative position they are below the worksurface and in a second operative position they project sufficiently to push the workpieces to the discharge station.

8. Apparatus according to any preceding claim, the securing means comprising a welding head.

9. Apparatus according to Claim 8, there being a plurality of welding heads each comprising two ultrasonic welding head devices.

10. Apparatus according to Claim 9, there being four welding heads arranged orthogonally whereby to provide four welding zones.

11. Apparatus according to Claim 10, each welding head device comprising a cylindrical rod with a frusto-conical welding tip.

12. Apparatus according to any of Claims 9 to 11, the welding heads comprising means for cooling the welding head devices and/or a weld formed between the workpieces.

13. Apparatus according to Claim 12, the cooling means comprising a jet directed towards the welding head devices and connected with a source of air.

14. Apparatus according to any of Claims 9 to 13, the welding heads being mounted on support means whereby the relative spatial disposition of the welding heads are adjustable in the apparatus.

15. Apparatus according to any of Claims 2 to 14, the worksurface including guide rails spaced above the worksurface whereby to maintain desired relative positions of the workpieces during transport and welding.

16. Apparatus according to any of Claims 5 to 15, the gripping pressure of the jaw means being adjustable.

17. Apparatus according to any preceding claim, the worksurface comprising a plurality of work stations.

18. Apparatus according to any preceding claim, including electronic control means for operating the respective transport means and securing means.

19. Apparatus according to Claim 18, the electronic control comprising timer means.

20. Apparatus for securing superposed weldable workpieces together, substantially as hereinbefore described with reference to the accompanying drawings.