GB2023735A

GB2023735A - Pressure-applying unit

Info

Publication number: GB2023735A
Application number: GB7923395A
Authority: GB
Original assignee: ACE VULCANISING Ltd
Current assignee: ACE VULCANISING Ltd
Priority date: 1978-04-05
Filing date: 1979-07-05
Publication date: 1980-01-03
Also published as: GB2023735B

Abstract

A self-contained pressure applying unit has a base plate 26 and cover 32 enclosing hydraulic rams 30, 31 for connection to a pressure source through a common connector 25, so that upon pressurisation of the rams the base plate and cover are forced apart. When the unit is inserted between a support beam and heater platen of an on- site vulcanising press it can be used for applying pressure and heat to, for example, a conveyor belt joint to be vulcanised. <IMAGE>

Description

SPECIFICATION Pressure-applying unit The present invention relates to pressure-applying units, and particularly to self-contained units having a range of potential uses rather than being designed for a single particular use.

Embodiments of the present invention find particular utility as pressure applying means in "on-site" vulcanising presses. Such presses are used, for example, to complete vulcanised joints in conveyor belts upon assembly, or for repair. Such operations usually have to be completed "on-site", that is, at the location where the conveyor belt is to be used, since the belt usually has to be threaded through its working path before its ends are joined.

Known on-site vulcanising presses generally comprise a pair of interconnected parallel beams spaced apart by a distance sufficient to permit the insertion between them of the ends of the conveyor belt, followed by the insertion of respective platens incorporating electric heaters between the opposite sides of the conveyor belt and the adjacent beams, which extend traversely across the belt. The beams incorporate hydraulic rams which are extended to press the heater platens together so as to press the ends of the conveyor belt together, whereupon the heaters of the platens are energised to complete the vulcanisation.

In order to accommodate a wide range of conveyor belt widths and thicknesses an onsite vulcanising press has to have a wide range of sizes of platens and transverse beams. An object of the present invention is to provide a pressure applying unit which can be inserted between each heater platen and the adjacent transverse beam of an on-site vulcanising press so that the latter does not have to incorporate rams.

According to the present invention, there is provided a self-contained pressure applying unit comprising at least two hydraulic rams connected in parallel to a common connector and mounted between two freely movable pressure-applying members to which the rams apply outward pressures tending to force the members apart when hydraulic fluid under pressure is fed to the said common connector.

The common connector is conveniently a quick-release coupling incorporating a closure valve for sealing the rams when the coupling is disconnected from the hydraulic pressure.

In this way a single source of hydraulic pressure can be used to pressurise a plurality of pressure applying units in turn.

It is envisaged that the same pressure applying units would be used with different sizes of transverse beams in a vulcanising press so that an overall economy is obtained in the equipment required for on-site vulcanising.

Moreover, the self-contained applying units, being designed to apply pressure between two pressure-applying members, can be used for on-site application of pressure in situations where it has hitherto been necessary to employ specially designed equipment.

Although a minimum of two hydraulic rams are required to effect balanced pressurisation with the pressure-applying members parallel to each other, there may be more than two rams between the said two pressure applying members.

The number of pressure applying units positioned between a transverse beam and the adjacent heating platen of an on-site conveyor belt vulcanising press will depend on the dimensions of the conveyor belt to be vulcanised; thicker belts may require more than one row of pressure applying units although in many cases a single row will suffice.

In a preferred embodiment of the invention one of the said pressure applying members is a base plate serving as a pressure plate and the other of the said pressure applying members in the form of a cover fitting over the hydraulic rams and the base plate and to which the cylinders of the said rams are connected, the said base plate carrying a support for the said common connector.

The present invention also comprehends an on-site vulcanising press comprising a pair of heater platens, a pair of parallel support beams, means for inter-connecting adjacent ends of the two beams so that they are spaced apart, the said heater platens lying between and parallel to the beams in use of the press and a plurality of pressure applying units as hereinbefore defined inserted between one of the said support beams and the adjacent heater platen for the application of pressure and heat to a workpiece such as a conveyor belt extending, in use of the press, between the two heater platens.

The invention will now be described, by way of example, with reference to the accompanying purely diagrammatic drawings, in which: Figure 1 is a perspective view of an on-site vulcanising press employing pressure applying units of the present invention; Figure 2 is a perspective view of a pressure applying unit according to an embodiment of the present invention, and Figure 3 is a cross section taken on the line Ill-Ill of Fig. 2.

Referring first to Fig. 1, the on-site vulcanising press shown comprises two pairs of parallel beams 12, 13, 14, 15 which are interconnected by respective tie bolts 17, 18, 19, 20, secured in position by respective clamping nuts 17a, 18a, 19a, 20a. Between the two pairs of transverse beams there are located two parallel platens 21, 22 incorporating electric heaters and extending transversely across a conveyor belt 23, adjacent ends of which are sandwiched between the platens 21,22.

The lower heater platen 22 (as shown in Fig. 1) rests directly on the two adjacent transverse beams 14, 1 5, but between the upper heater platen 21 and the transverse beams 1 2, 1 3, adjacent thereto there are inserted a number of, in this case three, pressure applying units 24 according to the invention. One such unit 24 is illustrated in greater detail in Figs. 2 and 3.

The pressure applying unit 24 shown in Figs. 2 and 3 is a self-contained portable unit having a generally rectangular shape in plan, with a quick-release coupling 25 projecting outwardly from one corner. The unit 24 comprises a base plate 26 having a bracket 27 supporting the quick release coupling 25. To the base plate 26 are attached the piston rods 28, 29 of two hydraulic rams 30, 31, the cylinders of which are connected to a cover 32 which has a peripheral flange 33 which rests within a rebated portion of an upstanding wall 34 around the periphery of the base plate 26, so that the cover 32 and base plate 26 can move apart, from the closed position shown in Fig. 3, while remaining parallel to each other, and without separation of the flange 33 from the wall 34.

The quick release coupling 25 incorporates a valve which is closed automatically when the coupling 25 is disconnected from a pressure line.

The quick release coupling 25 is connected to a union 35 which in turn is connected to two steel tubes 36, 37 leading to the cylinders 30, 31 respectively.

Respective return springs 38, 39 surround the respective piston rods 28, 29 to bias the respective rams 30, 31 into their retracted positions.

In use of the unit 24 a hand-operated or electrically driven hydraulic pump is con nected to the quick release coupling 25 and hydraulic fluid under pressure is supplied thereto. The fluid is fed to the two rams 30, 31 via the tubes 36, 37 respectively causing the rams 30, 31 to extend, and thereby forcing the cover 32 and the base plate 26 apart and applying outward pressure to any elements, such as the heating platen 21 and transverse beams 1 2, 1 3 illustrated in Fig. 1, between which the unit 24 may be located.

The flange 33 on the cover 32 serves to guide the cover 32 during such extension, the maximum stroke of the rams 30, 31, being such that they cannot push the cover 32 beyond the point where the flange 33 thereof separates from the wall 34 of the base plate 26.

A plurality of pressure applying units 24 may be pressurised simultaneously by connecting them in parallel to a single hydraulic pump, either hand- or electrically operated, the capacity of which is at least equal to the extended volume of the total number of hydraulic cylinders in use.

Alternatively, individual pressure applying units 24 may be pressurised individually from a common pressure source which is connected in turn to the respective couplings 25 of the units 24. Upon disconnecting the pressure source from each unit 24 the valve in the coupling closes and seals the rams of the unit, effectively locking the rams.

After use of the unit 24 the hydraulic rams of the unit are depressurised by manual opening of the valve in the coupling 25, whereupon the rams 30, 31 retract automatically under the influence of the return springs 38, 39, causing the cover 32 to close upon the base plate 26 until the flange 33 abuts the internal shoulder of the rebated upstanding wall 34.

Claims

1. A self-contained pressure applying unit comprising at least two hydraulic rams connected in parallel to a common connector and mounted between two freely movable pressure-applying members to which the rams apply outward pressures tending to force the members apart when hydraulic fluid under pressure is fed to the said commone connector.

2. A unit according to Claim 1, in which the said common connector is a quick-release coupling incorporating a closure valve for sealing the rams when the coupling is disconnected from the hydraulic pressure.

3. A unit according to Claim 1 or Claim 2, in which one of the said pressure-applying members is a base plate serving as a pressure plate and the other of the said pressureapplying members is in the form of a cover fitting over the hydraulic rams and the base plate and to which the cylinders of the said rams are connected, the said base plate carrying a support for the said common connector.

4. A unit according to Claim 3, in which the base plate and cover have respective peripheral surfaces which are in sliding engagement with each other to guide the base plate and cover for relative movement parallel to each other.

5. A unit according to any one of Claims 1 to 4, in which each ram has a return spring urging it into a retracted position.

6. A pressure applying unit substantially as herein described with reference to and as shown in Figs. 2 and 3 of the accompanying drawings.

7. An on-site vulcanising press comprising a pair of heater platens, a pair of parallel support beams, means for interconnecting adjacent ends of the two beams, so that they are spaced apart, the said heater platens lying between and parallel to the beams in use of the press, and a plurality of pressure applying units as claimed in any of Claims 1 to 6, inserted between one of the said support beams and the adjacent heater platen for the application of pressure and heat to a workpiece extending, in use of the apparatus, between the two heater platens.

8. An on-site vulcanising press according to Claim 7 in which the said means for interconnecting the support beams comprise tie-bolts passing through holes in the ends of the beams and secured by respective clamping units.

9. An on-site vulcanising press according to Claim 7, substantially as herein described with reference to and as shown in Fig. 1 of the accompanying drawings.