NO132468B - - Google Patents

Description

The present invention relates to a casting machine comprising first and second molds which are inserted in a casting station

are loaded movable to and from a casting position, as well as at least one foil transfer device for transferring a foil to one of the mold tools when this is out of the casting position, which foil transfer device comprises a carriage movable between a first and a second position, drive device for movement of Libra

nen, a foil carrier mounted on the carriage including a housing with an axis of symmetry and with a peripheral surface for receiving a foil and openings in the peripheral surface, means for placing a foil tangentially on the peripheral surface of the carrier when the carriage is in the first position, as well as control means which cause negative pressure at the openings when the carriage is in the first position and which causes the

ket is removed from the openings when the carriage is in the second position,

whereby a foil carried on the carrier is transferred to a forming tool when the carriage is in the second position.

A casting machine of this type is known from Norwegian patent no. 125 965. However, the known machine has limited application as the foil carrier in the transfer device is only capable of receiving relatively small pieces of foil, so that with this machine it is not possible to transfer a foil that can extend over a larger part of the circumference of the female form.

The purpose of the present invention is to provide

fe a molding machine where the foil transfer device can transfer a foil of such a large extent that it reaches over the entire female form

while around ts.

This is achieved by the carrier being rotatable around the symme-triax and by the device also comprising a drive device for ro-

rotate the carrier around its axis of symmetry, as the control elements include

includes means which cause the carrier's drive device to be actuated to rotate the carrier when the carriage is in the first position so that

a foil, which is placed tangentially on the peripheral surface of the carrier by the positioning means, is progressively taken up on the peripheral surface of the carrier.

The foil transfer device at the molding machine according to the invention is thus capable of handling a decorative foil or a construction foil so that this will extend in whole or in part around a molded product.

Further features and advantages of the present invention will be apparent from the following description of an example of an embodiment of the invention seen in connection with the accompanying drawings, in which: Figure 1 is a front elevation of a mold tool in an injection molding machine and schematically showing foil portioning and the transfer device, seen along the line I-1 in Figure 2. Figure 2 is a plan view of part of the molding machine in Figure 1. Figure 3 is a schematic section through a mold tool, mold tool carrier and guide devices therefore.

Figure 4 is a section through a foil carrier.

Figure 5 is an end elevation of the foil carrier in figure

4. Figure 6 is a section through a magazine for foils for use in the machine in figures 1 and 2.

Figure 7 is a section along the line VII-VII in the figure

6.

Figure 8 is an end view of another embodiment

of the foil carrier for use in the machine in figures 1 and 2.

Figure 9 is a plan view of the foil carrier. in_„figure 8..

The injection molding machine comprises a fixed tool carrier

1 and a movable tool carrier 2 controlled by guide rods 3 between an open position (fig. 2) and a closed forming position in which the forming tools 4, 5 together define the mold cavities M which will be equal in number to the compressions to be made in each forming cycle.

The tool 4 is a double tool movable across the direction of movement of the carrier 2 and comprises parts 6, 7 each of which, together with the tool 5, will define a set of mold cavities. When one part 6 is in the forming position (as shown in Figure 1) against the fixed carrier 1, the other 7 is in an outer position outside the path of movement for the carrier 1 and tool 5. For controlling the double tool 4 in its transverse movement is the arranged guide rails 8"

The tool 4 is shown as a six-piece press-

in

cloth and is designed for the production of thin-walled containers,

as described in British Patent No. 348,370

(application no. 23273/70), as each part 6, 7 of the tool 4 of

borders six cavities 9 and the tool 5 six cores 10.

The casting machine comprises a foil transport device or apparatus including a pair of carriages 11 on each of which are mounted six foil carriers 12. Each foil carrier 12 comprises a body 120 with an axis of symmetry 120a about which the carrier is rotated

bar and defines a peripheral surface 120b for receiving a foil.

In the present embodiment, the body 120 has the shape of a straight truncated cone corresponding to the shape of a cavity 9 and retains

pure to be produced therein. Each of the carriers 12 is coaxial with a cavity 9 of one part 6 or 7 of the tool 4 when this

is in the outer position in relation to the tool's 5 path.

Each carrier body 120 is rotatable about its axis on sealed

ball bearings 121 carried by a support 122 having channels 123, 124

connected to a vacuum source (not shown). Channel 12 3 is connected to a manifold 125 and then to a first set of openings 126 in carrier

body surface 120b, while channel 124 is connected to a mani-

fold 127 which in turn is connected to a plurality of openings 128

in the carrier body's surface 120b. The 0-rings 129 seal the manifold

those. A drive device, such as a motor 14, is mounted on

each carriage and is connected to the carriers of the carriage by a gear-

set (not shown), for which purpose each carrier has teeth 130.

Other forms of drive, such as chain or rack and pinion drive, can be used.

In a plane tangential to the surface of each

carrier is the surface of a guide element 15 on which slides a vacuum disk 16 which is connected to the vacuum source and is

movable by means of an arm 17 pivotally stored at 18 on

a tripod. A drive device for the arm of any kind will be able to swing the disk 16 from a position above a foil

magazine 19 to a position in which the leading edge of a foil held by disc 16 lies above openings 126 in the associated carrier. Application of. vacuum in the openings. 126, if necessary, the use of air jets directed at the front edge of the foil and the release of vacuum in the disk causes a foil carried by the disk to be attached to the carrier. Botas;)on of the carrier and application of vacuum at the openings 128 will then wrap the foil around and hold it firmly on the carrier. Advancing the respective carriage in the direction of the carrier axis will move the carriers into the empty cavities which. are located axially in line with the supports, and lifting the vacuum at the openings 126, 128 will release the foils from the supports, whereby each foil opens resiliently upon release from the respective supports and settles against the inner surface of the respective cavities. The carrier is then withdrawn. Filling, feeding, emptying

and retraction of the carriage and carriers occurs during the execution of the forming cycle. On completion of this cycle, the tool 5 is retracted and the tool 4 is moved transversely to move the empty mold cavities to their outer position out of the path of the moving tool for filling foils and the filled cavities are brought into the forming position in the path of the tool 5 for a new forming cycle. The carriages can be operated using piston-cylinder devices or by rack and pinion operation.

Each magazine 19 is specifically designed to ensure that only a single foil is taken up by the respective vacuum disks 16. As shown in figures 6 and 7, each magazine consists of a lower fixed part 202, an upper part 203 which is telescopically movable in relation to part 202, and a foil stowing part 204. Part 204 is movable by means of a piston-cylinder arrangement (not shown) in magazine 19 to hold and press a stafcel foil 205 in the magazine against foil edge-retaining lips 206 on magazine part 203.

The upper magazine part 203 is controlled in its movement

in relation to part 202 by fingers 207 fixed in recesses in part 202 and extending into recesses in part 203. These fingers 207 also prevent foils in magazine 19 from moving into the gap between the two magazine parts 202, 203» Magazine part 203 is spring-loaded for movement away from the part 202 by means of springs 208 placed in bores 209 in the parts

and is moved towards the part 202 into an abutting relationship thereby by means of a piston-cylinder device (not shown).

Foils are individually removed from the magazine by means of the vacuum disk 16. The disk 16 is movable about the pivotable support 18 from a foil receiving station above the magazine to near the foil carrier by means of a piston-cylinder arrangement (not shown) which acts on the arm 17, and by the foil receiving station to and from a recording position as shown in the figures, by means of a piston-cylinder arrangement 211. The disk 16 is pivotally mounted on the arm 17 and the piston-cylinder arrangement 211 is mounted between the disk 16 and the arm 17 for relative pivoting movement.

In operation, with the disk 16 in the foil receiving station, with the magazine portion 203 in contact with the portion 202 by means of its piston-cylinder arrangement and the foil pressure-loaded by the back-up portion 204 against the lips 206, the piston-cylinder arrangement 211 causes the disk 16 to swing down into the foil receiving position . Suction is applied to the vacuum disk 16, which thereby grips the upper foil in the magazine, figure 6. The upper magazine part 203 is then moved upwards under the load of the springs 208 so that the foils in the magazine are released from the compressive force exerted on them by the lips 206.

Finally, when the disc 16 is swung back to its original position by the piston-cylinder arrangement 211, the upper magazine part 203 is moved by its piston-cylinder arrangement (not shown) against the load of the springs 208 back into abutting contact with the part 202.

During these two final movements, the foil gripped by the disk 16 is pulled past the lips. 206 by being pulled in this way, it is slightly bent downwards in the presence of the lips. This bending causes any further foil carried along to break free from the contacted foil so that such a foil will be held back in the magazine by the lips 206.

This bending is effective due to the removal of the compressive force on the stack of foils by the upward movement of the magazine part 203.

The disk 16 and the foil are then moved to the respective foil carrier, whereby the vacuum is removed from the disk

16 so that the foil is released from there.

Although the magazine and vacuum disk described above are controlled by piston-cylinder devices to which compressed air or other fluid is supplied, the control can alternatively be done electrically.

In the apparatus described above, the magazine is

19 shown and described as vertically oriented. The magazine for the different foil carriers can, however, have varying inclinations in relation to the vertical, as shown in figure 1. -

Any form of control can be used

to ensure a correct sequence and distance between movements and for the application and release of vacuum and operation of air jets if such are arranged.

The design of the support body can vary according to

needs depending on the shape of the mold cavity and the object to be produced in it. For example, the carrier body can be cylindrical or frustoconical, as described above, or it can have an oval or polygonal or partially rectilinear, partially curved cross-section as desired.

A carrier with a tapered square cross-section

are shown in figures 8 and 9 for use in connection with correspondingly designed forin tools. The carriers 312 replace the carriers 12 in the above-described embodiment with a corresponding replacement of the tools 4-, 5.

The carrier 312 consists of a body 320 with a generally square cross-section and is rotatable about its axis of symmetry 320a in the same way as described in connection with the carrier 12. The peripheral surface 320b of the carrier is provided with a plurality of openings 326, 328 connected to a vacuum source.

As in the above-described embodiment, a foil 205 is fed tangentially in the direction of arrow A to the flat part of the carrier body's peripheral surface 320b with the openings 326. When the foil is placed by means of the vacuum disk 16 over the openings 326 with the leading edge immediately above the farthest corner 337 of the surface part , the vacuum is released on the disk 16, the vacuum source is connected to the openings 326 and 328 successively and the carrier is rotated so that the foil is pulled down and held firmly on the carrier surface as in the above described embodiment.

The carrier is then moved axially into the cavity which has corresponding dimensions, as described above.

In order to assist and ensure proper wrapping of the foil around the surface of the carrier body, one or more leaf springs 338 may be arranged over the upper surface portion and be tensioned into contact with this. In operation, the leaf spring 338 is moved from its operative position by the vacuum disk 16 when this brings a foil to the carrier, but is moved back into position when the disk is pulled away again. It is also moved out of the carrier's path when the carrier is moved axially into the cavity.

In a modification, the leaf spring 338 can be replaced by a freely rotating roller spring tensioned down against the surface of the carrier body.

The device has a high production capacity due to the short dead time and can be used to produce products that have a decorative and/or informative foil in connection with the product's design or it can be used to produce products in which the foil itself forms a structural part of the product, such as a perimeter wall of a container. Such a container and a method for producing it are the subject of the previously mentioned British patent.

In addition to using the carriers for applying a foil to the peripheral wall of a mold cavity, they can be used to carry a foil to the end of a mold cavity and which is then applied by another carrier or by another swing arm and vacuum disc. In that case, devices may be required to blow the foil off the carrier and into the mold cavity and it may be desirable to apply a static charge to the foil to hold it firmly in the mold cavity.

While an apparatus has been described in which the fixed tool alternates between each forming cycle for filling purposes, it is also possible to alternate the tool which is normally the moving tool.

As described, a foil is fed to a foil carrier from a magazine by a suction disc. However, the apparatus can be modified so that each magazine is positioned relative to

.its carrier in such a way that the next foil to be withdrawn is placed tangentially to the surface of the carrier, that application of vacuum to the carrier openings causes the foil to be picked up by the carrier and that rotation of the carrier causes the foil to be withdrawn from the magazine and at the same time is wrapped around the carrier. ■-

The term "foil" as used herein is intended to include any flexible sheet material, such as synthetic plastic or metal foil, paper, cardboard or any laminated or coated sheet material whether permeable or impermeable to fluids. The material can be smooth or printed and with varying opacity as desired.

Claims (1)

Ø$ jp- Casting machine comprising first (4) and second (5) casting molds which in a casting station are mutually movable to and from a casting position, as well as at least one foil transfer device for transferring a foil to one of the mold tools when. this is out of casting position, which foil transfer device comprises a carriage (11) movable between a first and a second position, drive device for movement of the carriage, eh foil carrier (12) mounted on the carriage including a housing (120) with an axis of symmetry* (120a) and with a peripheral surface (120b) for receiving a foil and openings (126, 128) in the peripheral surface, means (16) for placing a foil tangentially on the carrier's peripheral surface when the carriage is in the first position, as well as control means which cause negative pressure at the openings (126, 128) when the carriage (11) is in the first position and which causes the negative pressure to be removed from the openings (126, 128) when the carriage (11) is in the second position, whereby a foil carried on the carrier (12) is transferred to a form tool (4) when the carriage is in the second position, characterized by the bearer. (12) is rotatable around the axis of symmetry and that the apparatus further comprises drive device (14) to rotate the carrier (12) around its axis of symmetry (120a), the control means including means which cause the carrier's drive device (14) to be influenced to rotate the carrier (12) ) when the carriage (11) is in the first position so that a foil, which is placed tangentially by the placing means (16) on the circumferential surface of the carrier (12) • 4-^<-4- r,å weren's (12) circumferential surface. (120b), is progressively taken up on the u^i circumferential surface of the carrier.