The present invention relates to a hydraulic actuator or machine element.

With many hydraulic devices currently used, it is difficult to achieve a fast and smooth motion or pressure. For ex¬ ample, in hydraulic presses using cylinders and pistons to generate a pressure, especially in presses where the sur¬ face area receiving the pressure is large, it is necessary to use several pistons to produce the required pressing force.

Hydraulic cylinders are usually of a round sectional form. Due to the form and the materials used, they have a low resistance to pressure and heat. The object of the present invention is to eliminate the drawbacks mentioned and create a device or element that sustains a wide range of temperatures as well as high pressures. The hydraulic actuator or machine element of the invention is character¬ ized in that it comprises a layer of rubber, elastomer or quivalent which undergoes deformations under the pressure of a hydraulic fluid, which moves or presses a solid object by the aid of the deformations of at least one such layer, or, alternatively, which layer transmits at least part of the moving or pressing force either directly or via a medium or media; further, a connector for inlet of hydrau¬ lic fluid into the device or element and at least one sealing surface or both, having a layer of elastic material as indicated above, said layer being so shaped that the forces produced in it by the pressure are directed against metallic walls.

When under pressure, elastomers behave like fluids. They tolerate high temperatures as well as high pressures.

A preferred embodiment of the actuator or machine element of the invention is characterized in that, to connect a hose or equivalent to a counterpart having a conical nozzle, the connector comprises a clamping element fitted to the nozzle, the end of the hose or equivalent being squeezed between the nozzle and the clamping element, and a sealing element pressing the hose or equivalent, said sealing and clamping elements having a space filled with an elastic substance, e.g. an elastomer, to tighten the joint.

Another preferred embodiment of the actuator or machine element of the invention is characterized in that said sealing surfaces are comprised in said elastic layer.

The characteristics of other preferred embodiments of the actuator or machine element of the invention are presented in the other claims.

In the following, the invention is described by the aid of examples, reference being made to the drawings attached, wherein:

Fig. 1a presents a press.

Fig. 1b presents a section through the press.

Fig. 1c presents a detail of the press.

Fig. 2 presents a press unit.

Fig. 3a presents a structure in which layers of silicone rubber inside a frame, together with a metal plate, act as a press.

Fig. 3b shows, how said plate can be used as a brake block in a disc brake for a vehicle.

Fig. 3c presents a clutch.

Fig. 4a presents a regulating element controlling the lever of a valve.

Fig. 4b presents a cutter.

Fig. 5 presents a press unit.

Fig. 6 presents another press unit.

Fig. 7a presents yet another hydraulic press element.

Fib. 7b presents a press.

Fig. .8 presents yet another press.

Fig. 9 presents a press using several hoses.

Fig. 10 presents a press which can be used e.g. as a waste mill.

Fig. 11 presents an elevator frame.

Fig. 12 presents a machine element.

Fig. 13 presents a connector.

Fig. 14 presents another machine element.

Fig. 15 shows an edge of a press.

Fig. 1a shows a press designed for pressing various materials, e.g. veneer V, and Fig. 1b shows the same press in lateral view. The press consists of an upper 1 and a lower 2 metal box, in which the pressing surface consists of a metal plate and a layer of silicone rubber attached to

it. Using a pump, the oil in the oil space enclosed by the pressing surface and the metal box is pressurized to press together the surfaces of objects brought into contact by mechanical means. A press constructed as exemplified by Fig. 1a has two metal plates 3 and 4.

The pressing operation is started by raising the lower frame part 2 of the press to the desired height by means of eccentric gears 7 located below the frame and controlled by a cylinder 5 and a piston 6. The eccentric gears 7 adjust the vertical position of the frame parts by means of levers 8. The lower box 2 is then interlocked at the desired height, whereupon the pressure in the oil chamber is increased to the desired value by pumping oil into it. As the pressure rises, the objects to be coated are squeezed together between the pressing surfaces.

Fig. 1c presents a magnified view of detail A of the press. The surface 10 facing the hydraulic oil 9 consists of a shaped, e.g. corrugated film 10 able to withstand the de¬ formations caused by the pressurized fluid. The film is at¬ tached to a layer 11 of elastic material, such as silicone rubber, which damps its motion and, together with the metal plate 3, transmits the pressing force to the object to be pressed. The film 10 is also attached to the frame struc¬ ture 1. The hydraulic pressure causes the silicone rubber layer to be pressed against the wall of the frame structure.

Fig. 2 shows a press unit in which the pressing force is transmitted from the metal plate 12 and silicone rubber layer 13 to the object via a second metal plate 14. This second plate is provided with a protrusion 15 to limit its motion. The layer 13 of silicone rubber is so placed in the frame 16 that the hydraulic pressure pushes the lower part of the layer 13 towards a shoulder 19 in the frame 16, thus preventing the silicone rubber from getting out of the

frame. In addition, the frame has a cut-out 20 to limit the motion of the rubber layer. The metal plate 12 has a corre¬ sponding shape at the side which is in contact with the silicone rubber layer. Moreover, the metal plate 12 is pro¬ vided with a guide 21 to keep it in the correct position.

Fig. 3a presents a pressing device constructed along the principle illustrated in Fig. 2. The metal plate 23 and the silicone rubber layers 18 inside the frame 16 act as a press in which the pressing force is generated e.g. by a hydraulic fluid 17 supplied via a valve through an opening 22. The pressing force is transmitted via a second plate 24. Fig. 3b shows how the disc brake of a vehicle can be constructed using said plate 24 as the brake block, which, when the brake is applied, is pressed against the brake disc 26 rotating on a shaft 25. In Fig. 3c, the plate 24 is similarly used as a clutch disc which, rotating on a shaft 27, engages another disc.

Fig. 4a presents a regulating device used e.g. to control the lever 28 of a valve. Inside the frame 29 is a piston 31 which is controlled by a cushion 30 of silicone rubber and moved by the pressure of a hydraulic fluid 32. Fig. 4b shows a cutter 32 which may replace the piston 31. In this case, the device can be used as a cutting apparatus.

Fig. 5 presents a press unit comprising a frame 33, a layer 34 of silicone rubber, a pressing plate 35 and a chamber for the hydraulic fluid 36. The pressing plate 35 is pro¬ vided with a protrusion 37 extending into the silicone rub¬ ber layer. In this way the pressing plate is held in con¬ tact with the rubber layer, thus allowing a reciprocating motion. Fig. 6 shows a press unit constructed in the same way except that the frame in Fig. 6 is of a rounded form whereas the frame in Fig. 5 is rectangular.

Fig. 7a shows yet another press element, in which the frame

39 has a space for a layer of silicone rubber 40 inside it. Inside the silicone rubber layer is a hose 43 carrying a hydraulic fluid which, via the silicone rubber layer, controls a movable piston 41. The end of the piston is provided with a sealing piece 42. Such a device can be used as a sealing element to prevent oil leakages in a press as shown in Fig. 7b. The press comprises the frame parts 44 and 45, a plate 46 and two sealing elements 47 and 48 of the kind illustrated in Fig. 7a. Above the plate 46 there may be a mould 49 and an object 50 to be pressed. In other respects the two halves of the press unit correspond to the structure illustrated e.g. by Fig. 1c, so they will not be described here in detail.

Fig. 8 presents a press comprising a frame 51 , a rubber layer 52 and a plate 53. Again, the hydraulic fluid is carried by a hose 54. As shown by this figure, the shape of the hose or other space for the hydraulic fluid may vary. In the example in Fig. 8, the hose is considerably larger in the width dimension than in the height dimension. The structure in Fig. 9 uses several smaller hoses 55 instead of one large hose 54.

Fig. 10 presents a press which can be used e.g. as a waste mill. It has an input orifice 56, a nozzle 57 and a press unit consisting e.g. of a pressing device as shown in Fig. 3a and a feed screw 59 to allow a larger motion. The waste material is supplied into the mill via the input orifice 56 and then squeezed against the nozzle by the press unit. The desired pressing force is achieved by adjusting the press to the desired level by means of the feed screw, whereupon hydraulic pressure is applied.

Fig. 11 shows an elevator frame in which the platform 60 is raised and lowered by means of lever arms 61. Near the joints of the arms there are lifting elements 62, which may be constructed e.g. as illustrated by Fig. 3a.

Fig. 12 presents a machine element in which, by means of a wobbler 65 mounted on crank arms 63, the rotary motion of a shaft 64 is converted into reciprocating motion of a cylinder structure as illustrated in Fig. 6. In a contrary case, the reciprocating motion of a cylinder element is converted into rotary motion of the shaft 64. The crank arms are mounted on their respective fulcrum pins 66.

Fig. 13 presents a connector through which hydraulic fluid is passed into a press, such as that in Fig. 2. The connector has a frame into which a hose 68 is inserted, and a nozzle 69 through which the hydraulic fluid flows into the press. The nozzle has a conical part 70 tapering towards the hose, and a ball-shaped part 71 at its end. The hose is fitted tightly on the conical and ball-shaped parts of the nozzle. The joint is tightened by an elastomer 73 fed into the cavity between the clamping element 72 and the nozzle 70. The same substance is also fed into the space between the hose and the frame. The nozzle is secured on the clamping element by means of a screw-on collet 74. The forces present in the connector are indicated by arrows. The connector shown in Fig. 13 may be connected to a similar connector at the other end, the latter connector being connected to a linear-motion piston, in which case the connector has a separating surface as indicated by the broken line, or to a rotary-motion piston. A tension spring, not shown in the figure, may be provided between the connectors.

Fig. 14 presents another machine element similar to that in Fig. 12. By means of an eccentrically rotating flange 77, the device converts the rotary motion of a shaft 76 into a reciprocating motion of pistons 78, which in turn impart this motion to machine elements constructed as shown in Fig. 6, connected to the pistons by rods 79. The machine element has a frame 75.

Fig. 15 represents an edge of a hydraulic actuator. The press has a frame 80, inside which a hydraulic fluid 81, via a hose 82 having a connector as shown in Fig. 13, imparts a motion to a sealing element 83 and a plate 84. The sealing element 83 and the plate 84 together transmit the motion e.g. to a piston 86 provided with a sealing element 85. A groove is provided at the edge of the piston sealing element to improve the sealing effect. The forces appearing in the device are represented by arrows. The pistons in the device in Fig. 14 may also be provided with sealing elements as shown in Fig. 15.

It is also possible to build a closed system in which e.g. a device like that in Fig. 12 or 14 is used to press an element constructed as shown in Fig. 9a. With this arrange¬ ment, temperatures as high as 300° and high pressures can be attained.

It is obvious to a person skilled in the art that different embodiments of the invention are not restricted to the examples discussed above, but that they may instead be varied within the scope of the following claims.