GB2038708A - Vacuum presses - Google Patents

Abstract

A vacuum press of the type comprising a bed upon which one or more substantially planar work pieces can be placed with a gas impermeable covering (70) thereover, and means for reducing pressure between the bed and the covering, the bed at least being of modular construction for ease of transportation such that a plurality of modules (10), (12) can be joined together to form the bed. <IMAGE>

Description

SPECIFICATION Vacuum presses This invention is concerned with improvements in or relating to vacuum presses.

Vacuum presses are employed, inter alia, in the bonding of laminated sheet form materials where it is essential that a substantially uniform pressure should be exerted upon several layers of a laminate in orderto ensure that a uniform bond is obtained at the interfaces of the layers over the whole area of the laminate. Reduced pressure is then applied to a chamber of the vacuum press to press an upper cover down onto the laminate under atmospheric pressure to allow the layers of the laminate to bond under pressures of approximately 5 Ibs per square inch or more.

These presses are of large size because they must be capable of accommodating large laminated panels, for example, such as are used in the construction of caravans or mobile homes. They are also very heavy machines being constructed from rigid steel sections and components. Previously vacuum presses have been assembled prior to transportation and delivery to a customer and the subsequent difficulties of transporting these machines, together with their attendant bulk has added significantly to their cost.

The present invention seeks to reduce this cost and to minimise these aforesaid difficulties by providing a press which can be transported in modular form for relatively easy assembly after delivery.

The present invention provides a vacuum press of the type comprising a bed upon which one or more substantially planarworkpieces can be placed with a gas impermeable covering thereover, and means for reducing pressure between the bed and the covering, the bed at least being of modular construction for ease of transportation, such that a plurality of modules can be joined together to form the bed.

There now follows a detailed description which is to be read with reference to the accompanying drawing of a vacuum press according to the present invention; it is to be clearly understood that this press has been selected for description to illustrate the invention by way of example only.

The drawing is an exploded front perspective view of a vacuum press according to the present invention.

The illustrated vacuum press comprises a bed and a canopy. The bed is of modular construction comprising two modules 10, 12 each of which comprises a substantially square multi-part plate 14 reinforced by transversely extending struts (not shown) and supported on spacers 16 from a square frame 18, the spacers 16 being welded to the plate 14 and to the frame 18. Between the plate 14, which is formed of sheet steel, and the frame 18 are welded elements 20, each of which has a plurality of bolt holes 22, which, when the elements 20 of the modules are placed in juxtaposed relationship, will be aligned for bolts to pass therethrough for clamping the two modules together. Each module is of rigid construction so that it can not flex or bend under load.

Each plate 14 has two elongate parallel apertures 24 through which retractable bearing members can project upwardly in the assembled press. These bearing members are provided by ball bearings 26 located in sockets 28 therefor, the sockets being mounted on a beam 30 at spaced intervals therealong, the beam being housed within a hollow housing 32 of rectangular section which can be fitted within a respective one of the apertures 24 so that its upper surface is flush with the upper surface of the plate 14. The upper surface of the housing 32 has a plurality of openings 36 through which the ball bearings can be raised and lowered.The vertical movement of the beam 30 is achieved by operation of two piston-and-cylinder arrangements 38 mounted on the underside of the plate, one at each end of the beam, so that the pistons 40 thereof can be extended to raise the beam within its housing to cause the ball bearings to project through the openings 36, the movement of the beam being limited by the internal height of the housing 32.

Each module 10, 12 of the bed of the press is supported on four leg units 42, each of which comprises a leg 44, having a height adjustment screw 46 in the base thereof, plate support members 48 and bracing members 50, welded together.

Viewing the drawing, the two right-hand leg units of the left-hand module 10 have been omitted.

The rearmost leg units have extensions 52 rearwardly thereof, each extension providing a mount 54 for pivotally securing, by means of a pivot pin 56, a respective piston-and-cylinder unit 58, which unit is provided for raising and lowering the canopy as hereinafter described. Each extension 52 also comprises a rearwardly and upwardly extending bracket member 60 which has a pair of pivot pin support plates 62 welded thereto for carrying a pin 64 whereby the canopy can be pivotally secured to the bed in the assembled press.

The canopy of the press comprises a rectangular frame 66 carried by a number of arms 68 pivotally secured by the pins 64 to the bracket members 60, and a gas impermeable membrane or diaphragm 70.

The frame 66 of the canopy is of multipart construction comprising two end pieces 72,74, each of which is of substantially U-shape to provide one end portion 76 of the frame and two short arm portions 78. The portions of each end piece are of hollow U-section; the two arm portions 78 accommodate, as a sliding fit, connecting members 80 whereby the end pieces 72,74, can be joined to longitudinal parts of the frame. The end portion of each end piece 72,74 also accommodates a member 82 having a cross-section which is the same as that of the connecting members 80. Each connecting member 80 is of external dimensions which are such that, as stated above, it can slide into the arm portion 78 where it is held in position by two flanges 82 which are spaced apart to define a gap for the purpose hereinafter specified.Each connecting member is of box-section with one face profiled to provide a groove or channel 84 which, when the member 80 is slid into its respective arm portion 78, is aligned with the gap between the flanges 82. Each member 80 is of a length such that an end portion thereof extends from the arm portion 78.

A U-shaped channel member 86 having an internal member 88 of the same cross-section as that of the connecting member 80 is arranged to fit on the end portion of the member 80 and to be secured thereto by bolts 90 passing through aligned bolt holes 91 in the end portions of the members 80 and 86. The internal member 88 in each channel member 86 has a groove or channel 92 aligned with the groove or channel 84.

At its other end, the member 86 is similarly provided with bolt-holes 91 whereby it can be bolted to a center connector 94 which is of the same cross-section as the member 80.

To the right, viewing the drawing, of the connector 94, there is a similar construction, including a channel member 86 and internal member 88 whereby the connecter 94 is rigidly connected to the end piece 74.

The rear of the frame 66 is similarly constructed to the front, comprising two channel members 86 joined by a center connector 94. The composite frame when assembled defines a continuous groove or channel in its outer face, which is intended to accommodate elongate rubber wedges 98 forming a friction fit in the groove or channel to trap edge portions of a gas impermeable covering or diaphragm 70. The diaphragm 70 is secured in position by wrapping the edge portions thereof up around the frame and then locating the wedges 98 in position.

Each end piece 72, 74 is welded to an arm 68, 68 respectively which extends from the front to the back thereof, and is pivotally secured to its respective bracket member 60 by the pivot pin 64. The two connectors 94 are welded to a similar arm 106 which is pivotally secured to its respective bracket member 60.

Each of the three arms 68 is pivotally connected to the piston of the associated piston-and-cylinder unit 58.

As will be appreciated from the foregoing description, the illustrated vacuum press can be readily assembled and dis-assembled for ease of transportation. In addition it will also be appreciated that if it is desired to extend the press to a larger size, this can be readily achieved by incorporating an additional module comprising a plate 14, its attendant leg units 42 and piston-and-cylinder arrangement 58, a further arm 68, connectors 94 and channel members 86. Of course to extend the size of the press it will be necessary to replace the diaphragm 70 and the band 98 by larger ones. It will also be understood that more than one additional module can be incorpo rated.

Claims (5)

1. A vacuum press of the type comprising a bed upon which one or more substantially planar work pieces can be placed with a gas impermeable covering thereover, and means for reducing press ure between the bed and the covering, the bed at least being of modular construction for ease of transportation such that a plurality of modules can be joined together to form the bed.

2. Avacuum press according to claim 1 wherein each module of the bed is supported upon a respective set of legs.

3. A vacuum press according to either one of claims 1 and 2 wherein the bed is provided with apertures through which retractable bearing members can be moved to lower or raise a workpiece to or from the bed in the operation of the press.

4. A vacuum press according to any one of the preceding claims wherein the canopy is of modular construction.

5. A vacuum press according to any one of the preceding claims wherein the canopy is mounted for pivotal movement so that it can be raised to open the press and lowered to close the press.