Abstract:
Stopcock actuator casing, comprising a base ( 1 ) having an underside and formed with a hole ( 2 ), the underside of the base being subdivided into at least three compartments ( 4,8,10 ), the first ( 4 ) of which surrounds the hole ( 2 ) and the second ( 8 ) and third ( 10 ) of which are each formed with two orifices ( 12,13,14,15 ) passing through the base ( 1 ).

Description:
FIELD OF THE INVENTION 
     This invention relates to an actuator. Specifically, the present invention relates to a sealing joint and casing for a stopcock actuator. 
     BACKGROUND 
     A stopcock actuator comprising a system for distributing drive fluid to the actuating cylinder of a seal is already known. The distribution system and the actuating cylinder are housed in separate envelopes which have to be connected by means of tubes or conduits. 
     This arrangement is bulky and makes assembly complicated. 
     SUMMARY OF THE INVENTION 
     The invention overcomes these drawbacks with a sealing joint and a stopcock actuator casing, in which the base of the casing is shaped so as to provide the connections for the distribution of fluid to the cylinder. 
     The base of the casing is, in particular, formed with a through-hole for a device for monitoring the position of the seal and the underside of the base is subdivided into at least three compartments, the first of which surrounds the hole whilst the second and third are each formed with two orifices passing through the base. The base may also be subdivided into at least five compartments each of which, with the exception of the first, has two orifices passing through the base, one of the orifices in the fourth compartment communicating on the upper surface of the base with one of the orifices in the second compartment, and one of the orifices in the fifth compartment communicating on the upper surface of the base with one of the orifices in the third compartment. These orifices provide a means of communication between the distribution system for the drive fluid and the cylinder, with the possibility of inserting a flow regulating device, e.g. in the form of a screw-type needle valve, in the orifice in the fourth compartment and the one in the fifth compartment communicating with one of the orifices in the second compartment and the third compartment. 
     Preferably, a sixth compartment is provided with a through-orifice and an orifice opening into a conduit provided in the base and opening outside the casing. This allows the drive fluid to escape from the actuating cylinder and also enables any fluid which has leaked into the inside of the casing to escape from there. 
     The invention also relates to a one-piece elastomer sealing joint shaped so as to define a mesh, at least in part, characterised in that it comprises, projecting into the mesh, a solid part attached to a first side of the mesh by means which enable the solid part to stand out from the plane of the mesh. Preferably, a flexible bar is provided linking the solid part to the first side of the mesh and another flexible bar is provided linking the solid part to the two sides of the mesh adjacent to the first side, the two bars being notably perpendicular. The solid part is able to move up out of the plane of the mesh under the effect of pressure or be returned thereto. Preferably, the solid part does not extend as far as the side opposite the first side. In any case, it is not attached thereto. Advantageously, it takes up one-third to two-thirds of the surface of the mesh. The joint may be in the form of a net and may define a plurality of meshes, at least two of which have a solid part. This sealing joint makes it possible to seal the pneumatic connections between the body of the cylinder and the casing of the actuator in a way which is very simple to produce and assemble. 
    
    
     In the accompanying drawings, which are provided solely by way of example: 
     FIG. 1A is a plan view of a stopcock actuator casing, with the joint shown in an exploded view (FIG.  1 B), and 
     FIG. 2 is a section on the line II—II in FIG.  1 A. 
    
    
     DETAILED DESCRIPTION 
     The stopcock actuator casing shown in FIG. 1A comprises a base  1  formed with a hole  2  in which there is a control spindle  3  adapted to be acted upon by a mandrel (not shown) by means of which the position of the seal can be controlled. The hole  2  is provided in a first compartment  4 . This first compartment  4  is substantially rectangular in shape. On one of the sides are provided two fixing holes  5  intended for a screw to pass through, whilst substantially at the top of the compartment but slightly towards the inside are provided two blind bores  6  which communicate via grooves  7  with the edges of the compartment, also in the form of a groove. 
     The base also has a second compartment  8 , a third compartment  9 , a fourth compartment  10  and a fifth compartment  11 . All these compartments are substantially in the form of a rectangle the perimeter of which consists of a groove. The surface of the casing comprises, in the second compartment  8 , a through-orifice  12  and an orifice  13  which communicates with an orifice  14  provided in the compartment  10 . The orifice  14  in turn communicates with an orifice  15  provided in the compartment  10 . Similarly, the compartment  9  has a through-orifice  16  and an opening  17  communicating with an orifice  19  in the compartment  11 . The orifice  19  communicates with an orifice  20  in the compartment  11 . 
     A sixth compartment  21  is provided, the perimeter of which consists of a groove. This compartment has two orifices  22  and  23 . The orifice  22  communicates with the outside of the casing, whilst the orifice  23  passes through and communicates with the inside of the casing. 
     Between the compartments  8 ,  9 ,  10 ,  11 , on the one hand, and  9 ,  11  and  21 , on the other hand, there are again provided two screw holes  5 , whilst between the compartments  9  and  21 , again, a blind fixing bore  6  is provided. 
     The sealing joint (FIG.  1 B), which fits in the grooves forming the sides of the compartments, is in the form of a net defining a plurality of meshes corresponding to the compartments. The substantially rectangular joint has two long sides  24 ,  25  and two short sides  26 ,  27 . The side  27  has two circular parts  28  delimiting a hole for the passage of screws. At the apices, bounded by the sides  24  and  27  and  25  and  27 , two lugs  29  each lead to a stud  30  adapted to project into the blind bores  6 . The joint also has two bars  31 ,  32  parallel to the side  26  and going from the side  24  to the side  25  and two bars  33 ,  34  parallel to the side  24 , the bar  33  going from the side  26  to the bar  31 , whilst the bar  34  goes from the side  26  to the bar  32 . The intersections of the bars  33  and  34  with the bar  32  comprise circular portions  28  for screw fixing. At the intersection of the bar  34  with the side  26  a stud  30  is also provided. Running diagonally from the bar  33  in the part corresponding to the compartment  10  is a bar  35  having a solid part  36 . This solid part is not connected to the other sides of the part of the joint corresponding to the compartment  10 , with the result that it can be raised or pressed down under the effect of pressure. Another bar  37  perpendicular to the bar  35  connects the bar  31  to the circular part  28 , but could equally connect the bar  31  to the bar  33 . In the same way, a solid part  38  is connected by the bars  39 ,  40  to the side of the joint corresponding to the compartment  11 . A solid part  41  is also provided in the part corresponding to the compartment  21 . This solid part  41  is connected to the bar  32  by a bar  42  and is also held by a bar  43 , perpendicular to the bar  42 . The solid parts  36 ,  38  and  41  are pressed respectively against the orifices  15 ,  20  and  23 . 
     Screw-type needle valves  47  are screwed into the orifices  14  and  19 . 
     FIG. 2 shows that the orifices  13 ,  14  and  15  communicate with one another via a chamber  44 , whereas the orifices  17 ,  19  and  20  communicate with one another via a chamber  45 . 
     The sealing joint is made of an elastomeric material ensuring a tight seal, whilst the base of the casing is preferably of metal but may also be of plastics. 
     When the actuating cylinder of the stopcock is to be supplied with compressed air, the orifice  12  is connected to a source of compressed air. The compressed air passes into the compartment  8  and then into the orifice  13  and emerges into the chamber  44 . As the chamber  44  communicates with the orifice  14 , the opening of which is reduced by the needle valve  47 , and with the orifice  15 , the opening of which is closed off by the solid part  36 , which opens up the orifice  15  under the effect of pressure, the air preferably passes through the orifice  15  into the compartment  10 , which is connected via a conduit  46  to the cylinder. 
     Conversely, when air is to pass from the conduit  46  to the outside, as the piston of the cylinder moves back, the air arriving in the compartment  10  cannot pass through the orifice  15  because the solid part  36  is now closing this orifice, but passes through the orifice  14 , at a flow rate controlled by the needle valve  47 , so that the rate of escape of the air can be regulated by tightening and slackening the needle valve  47 .