Abstract:
An actuation device for adjusting a powered control device opposite the adjusting direction. The actuation device comprises an actuation element axially displaceable in a housing by a feed device at least in the adjusting direction. The actuation device includes an emergency actuation arrangement that may be actuated from outside the housing of the device. The emergency actuation arrangement is connected in motion with the feed device via a direction-switched coupling device. The feed device includes at least one motor for turning a rotating spindle. The at least one motor is rigidly connected with a rotating sleeve mounted capable of rotating in the housing and surrounding the rotating spindle. The rotating sleeve is capable of being set in a direction opposite the feed direction of the rotating spindle relative to the housing.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a National Phase entry of PCT Application No. PCT/EP01/05158 filed 7 May 2001 which claims priority to German Application No. 200 08 414.3 filed 11 May 2000, both of which are incorporated herein by reference. 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not Applicable. 
     BACKGROUND 
     Actuator systems for shifting a control device that is pressure-loaded against the shift direction may incorporate an actuator element housed in a system enclosure that is axially movable at least in the shift direction by an internal advance mechanism. 
     An actuator system of this type has been known in prior art, serving to actuate control devices such as valves, pressure regulators and the like but most particularly for use in submarine oil and gas exploration and production equipment. The actuator system can be employed equally well in comparable land-based, difficult-to-access or remote equipment. 
     When the switching device is shifted against the direction of the pressure load, the actuator element is moved axially so that in its extended forward position it serves to shift the control device into the operational ready-state. When the actuator element is homed, i.e., moved back and away from the shift direction, the control device is deactivated. An actuator system of this type is provided with a suitable enclosure protecting it from the elements in a marine or land-based environment. With current actuator systems, however, it is not possible in an emergency to manually operate the system by simple external intervention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The following describes advantageous design examples of this invention in more detail with the aid of the figures in the attached drawings in which: 
         FIG. 1  is a front view of a first design example of an actuator system; 
         FIG. 2  is a cut-away view along line A–C in  FIG. 1 ; 
         FIG. 3  is a front view of a second design example of an actuator system; 
         FIG. 4  is a cut-away view along line A–C in  FIG. 3 ; and 
         FIG. 5  is a conceptual sectional view of a control device designed to connect to an actuator system. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     In the drawings and description that follows, like parts are marked throughout the specification and drawings with the same reference numerals, respectively. The drawing figures are not necessarily to scale. Certain features of the invention may be shown exaggerated in scale or in somewhat schematic form and some details of conventional elements may not be shown in the interest of clarity and conciseness. The present invention is susceptible to embodiments of different forms. Specific embodiments are described in detail and are shown in the drawings, with the understanding that the present disclosure is to be considered an exemplification of the principles of the invention, and is not intended to limit the invention to that illustrated and described herein. It is to be fully recognized that the different teachings of the embodiments discussed below may be employed separately or in any suitable combination to produce desired results. Any use of any form of the terms “connect”, “engage”, “couple”, “attach”, or any other term describing an interaction between elements is not meant to limit the interaction to direct interaction between the elements and may also include indirect interaction between the elements described. The various characteristics mentioned above, as well as other features and characteristics described in more detail below, will be readily apparent to those skilled in the art upon reading the following detailed description of the embodiments, and by referring to the accompanying drawings. 
       FIG. 1  illustrates a first design example of an actuator system  1 . An auxiliary trunnion  22 , with diametrically opposite pins for attaching from outside the actuator system  1  an underwater manipulator or similar tool, is accessibly located in a recess. Situated underneath the auxiliary trunnion  22  is a position-monitoring sensor  40  that is operationally connected to a motor shaft  23 , per  FIG. 2 , that is rotatable in the direction of advance rotation  12 . Located next to the positional sensor  40 , in the same recess in the motor cover  37 , again per  FIG. 2 , is a plug connector  66  for the connection of a cable by way of which data can be transmitted to or retrieved from the actuator system  1 . The recess accommodating the positional sensor  40  and the plug  66  can be tightly sealed by means of a cap  67 . 
     A tensioning motor  16  of an emergency release unit  15  is located beside the positional sensor  40  within the system enclosure  4 . The system enclosure  4  is sealed off at both ends by a motor cover  37  and, respectively, an enclosure lid  20 . Located inside the system enclosure  4  is an electric motor  9  that, by way of a drive unit  42 , turns a connecting sleeve  45 . The connecting sleeve  45  extends from the drive unit  42  to a cap nut  41  to which it is rigidly connected. A rotating spindle in the form of a ball-type revolving spindle  10  is bearing-mounted inside the cap nut  41 . A rotation of the cap nut  41  via the connecting sleeve  45  permits the rotating spindle  10  per  FIG. 2  to move in the axial direction. At its end opposite the motor  9 , the ball-type spindle  10  is provided with a spindle head  49  that, aided by radially protruding guide lugs  48 , can be shifted in longitudinal slots of a rotary sleeve  11 . The spindle head  49  is provided with a rotary mount that can be rotated relative to the rotating spindle  10  and is connected to an actuator element  6 . 
     The actuator element  6  is substantially rod-shaped and extends from an outlet end  19  in the enclosure lid  20  of the system enclosure  4 . For guiding the actuator element  6  in the direction of a control device  3  per  FIG. 5 , the enclosure lid  20  is provided with a guide sleeve  68  protruding from the actuator system  1 . At both ends of the guide sleeve  68 , appropriate seals support the actuator element  6  in water-tight fashion. 
     In the area of the spindle head  49  the rotating spindle  10  is surrounded by the rotating sleeve  11  which in relation to a casing  47  is pivot-mounted by way of appropriate bearings. At its end opposite the rotating sleeve  11 , the casing  47  is rigidly but removably attached to an annular disk  43 . At its end facing the rotating sleeve  11 , the casing  47  is provided with a circular flange  14  around which, and around the associated end of the rotating sleeve  11 , a volute spring  13  is wound. In its tensioned state, the volute spring  13  prevents any relative rotation between the casing  47  and the rotating sleeve  11  in the wrong direction. 
     Attached to the circular flange  14  and the rotating sleeve  11  is a tensioning sleeve  17  one end of which is pivot-mounted in the enclosure lid  20 , the other end on the outside of the circular flange  14 . At its end facing the circular flange  14 , the tensioning sleeve  17  is provided with internal gearing in which engages a gear  58  per  FIG. 4 . The gear  58  can be rotated by a tensioning motor  16  positioned to the side of the advance mechanism  5  constituted of the motor  9 , the connecting sleeve  45 , the cap nut  41  and the rotating spindle  10 . By way of suitable cams  50 ,  51  the tensioning sleeve  17  is connected to the volute spring  13  or, respectively, to a return spring  52 . By means of the cam  50 , a rotation of the tensioning sleeve  17  can bring the volute spring  13  into a tensioning position in rigid connection with the casing  47  and the rotating sleeve  11 . At the same time, as the tensioning sleeve  17  is turned, the cam  51  can pre-stress the return spring  52  as the torsion spring to a point where it applies a pressure load on the tensioning sleeve  17  in a direction of rotation opposite the sense of rotation transferred by the tensioning motor  16 . The combination of tensioning motor  16 , gear  58 , tensioning sleeve  17 , volute spring  13  and return spring  52  thus constitutes an emergency release unit  15  for the actuator system  1 . 
     An additional volute spring  46  is positioned between a ring extension  44  of the annular disk  43  and an outside area of the connecting sleeve  45 . The volute spring  46  transfers a return movement applied by the control device  3  on the actuator element  6  directly to the system enclosure  4 . 
     Opposite the rotating spindle  10  or the gear  58 , both the motor  9  and the tensioning motor  16  feature a motor shaft  23  or a tensioning-motor shaft, respectively. The motor shaft  23  is equipped with a gear  24  in the form of a free-wheeling gear with a coaster mechanism  25 , thus constituting a directional clutch unit  8 . The free-wheeling gear  24  engages in a drive gear  26  which is mounted on one end of the auxiliary trunnion  22 , with a slip-ring coupling  27  interpositioned between them. By means of the bearing  56  the auxiliary trunnion  22  is pivot-mounted in the motor-housing cover  37  in which it is also sealed by means of the seals  56 , thus protecting an inner space  21  of the system enclosure  4  from the marine or on-land environment surrounding the actuator system  1 . 
     The motor shaft  23  extends all the way to the positional sensor  40  which can thus gauge the rotations of the motor shaft  23 . 
     The free end  30  of the tensioning-motor shaft  28  is located inside a sleeve nut  29 . On its side opposite the tensioning-motor shaft  28 , the sleeve nut  29  is provided with at least one longitudinal slot  53  that guides a pin radially protruding from a threaded spindle  31 . At its spindle end  36  opposite the sleeve nut  29 , the threaded spindle  31  is pivot-mounted in the motor cover  37 . The threaded spindle  31  is equipped with a tensioning gear  32 . A slip-ring coupling  33  is provided between the threaded spindle  31  and the tensioning gear  32 . By way of an intermediate gear  69  per  FIG. 1  or  3 , the tensioning gear  32  is operationally connected to the drive gear  26 . 
     The sleeve nut  29  is adjustable between the stops  34  and  35 , per  FIG. 4 , depending on the direction of rotation of the threaded spindle  31  or of the tensioning-motor shaft  28 . The stop  34  is located on the tensioning-motor shaft  28 , the stop  35  is constituted of the end of the slot  53 . The distance between the stops  34  and  35  is shorter than the slot  53 . 
     The combination of auxiliary trunnion  22 , drive gear  26 , free-wheeling gear  24 , tensioning gear  32 , threaded spindle  31 , sleeve nut  29  and tensioning motor shaft  28  forms the emergency actuator assembly  7  by means of which, in the event power to the motor  9  or to the tensioning motor  16  is interrupted or some other problem interferes with the normal operation of the actuator system  1 , the actuator element  6  can be shifted into its operating position  2 . 
       FIG. 3  illustrates another design example of an actuator system  1 . In this figure as in the figures that follow, identical parts bear identical reference numbers, while the continued description of these components is based on  FIGS. 1 and 2 . In  FIG. 4 , the upper half shows the actuator element in the extended position  54 , the lower half shows it in its retracted position  55 . In the extended position  54 , the return spring  52  is cocked and applies return pressure on the tensioning sleeve  17 . In the second design example the enclosure lid  20  is provided with a plug-in sleeve  57  protruding into the inner space  21  of the system enclosure  4  and surrounded by the return spring.  52 . 
     Mounted in the motor cover  37  opposite the enclosure lid  20  are bearing boxes  38 ,  39  in which the auxiliary trunnion  22  and, respectively, the spindle end  36  of the threaded spindle  31  are pivot-mounted. The bearing boxes  38 ,  39  protrude outward in the longitudinal direction and past the motor cover  37 . The bearing box  38  also contains a suitable seal  64  for the auxiliary trunnion  22 . 
       FIG. 5  is a sectional cutaway view of a control device  3  that can be actuated by the actuator systems  1  per  FIGS. 2 and 4 . In  FIG. 5  the control device is provided on the right-hand side with a connecting end  59  into which the guide sleeve  68  of the enclosure lid  20  can be inserted. Suitable fastening provisions  70 , per  FIGS. 2 and 4 , serve to removably attach the actuator system  1  to the outer perimeter  71  of the connecting end  59 . 
     In the design example illustrated the control device  3  is equipped with a slide  62  that has a substantially circular slide opening  63 . In the upper half of  FIG. 5  the slide  62  is depicted in a position corresponding to the retracted state  55  of the actuator element  6 , in the lower half of  FIG. 5  it is shown in the extended position  54  of the actuator element  6 . In the extended position  54  of the actuator element  6  the slide  62  is open, in its retracted position  55  the slide  62  is closed. 
     At its end opposite the slide opening  63 , the slide  62  is provided with a takeup receptacle  60  to whose bottom the actuator element  6  is connected and removably attached. In  FIG. 5 , the takeup receptacle  60  is shown in the positions of the actuator element  6  corresponding to the extended position  54  and, respectively, retracted position  55  of the actuator element  6 . A return spring  61  is positioned around the takeup receptacle  60 , applying pressure on the takeup receptacle  60  in the direction of the retracted position  55  of the actuator element  6 . 
     In operation, running the motor  9  will move the actuator element  6  into its shift position  2 , in the process of which the rotary movement of the motor  9  is transferred via the connecting sleeve  45  and the cap nut  41  to the rotating spindle  10  and is converted into a translatory axial movement. The movement of the rotating spindle  10  causes a shift of the actuator element  6  along the guide slots in the rotating sleeve  11  up to its fully extended position  54 . In the course of or prior to this operation of the actuator system  1 , the rotation of the tensioning sleeve  17  by the tensioning motor  16  causes the cams  50 ,  51  to cock or tension the volute spring  13  and the return spring  52 . The tensioning of the volute spring  13  and return spring  52  holds the rotating sleeve  11  in a rigid position relative to the system enclosure  4 . 
     When the motor  9  turns, the directional clutch  8  prevents the auxiliary trunnion  22  from turning along with the motor  9 , reducing the operating load of the motor considerably and at the same time avoids any exposure of the seals  64  at the auxiliary trunnion to friction or even wear. In other words, the free-wheeling gear  24  works in a way that it does not turn during the normal opening process of the slide  62 . The holding function of the tensioning motor may then be deactivated, thus allowing the retractive force of the return spring  52  to turn back the tensioning sleeve  17 , releasing the volute spring  13 . The slide  62  may then be closed, and the actuator element  6  shifted into its retracted position  55 , by the resetting action of the return spring  61  of the control device  3 . This may be followed by the retraction of the actuator element  6  into the system enclosure  4  under the action of the return spring  61 , in the process of which the rotating spindle  10 , together with the rotating sleeve  11 , can be turned back for instance all the way to its position in the cap nut  41  indicated in  FIG. 2 . There is no concomitant rotation of the motor  9  since the actuator element  6  is reset by a revolving rotary spindle  10  while the cap nut  41  remains stationary. Thus, the emergency actuator assembly  7  and its components may remain in an idle standby state during normal operation, without requiring any further technical provisions, i.e., they are not moved in any way. 
     If in an emergency situation the slide  62  is to be opened by the emergency actuator assembly  7 , the auxiliary trunnion  22  is turned in the appropriate direction, in this case also turning the motor  9  by way of the free-wheeling gear  24  and coaster mechanism  25 , as a result of which the actuator element  6  is shifted into its extended position  54  described above. During this process the slip-ring coupling  27  on the drive gear  26  protects the motor  9  against excessive torque. 
     At the same time, by way of the intermediate gear  69  and the tensioning gear  32 , the tensioning motor  16  is set in motion to activate the emergency release unit  15 . The emergency release unit  15  is so designed that after only a few hundred revolutions of the tensioning-motor shaft  28  the volute spring  13  and return spring  52  are tensioned and by virtue of the slip-ring coupling  33  any further torque action on the tensioning motor  16  is prevented. 
     Thus, the emergency actuator assembly  7  ensures full safety and at the same time the emergency release unit  15  is activated. Since the motor  9  and, accordingly, the rotating spindle  10  or cap nut  41  require several thousand revolutions to fully open the slide  62 , the emergency release unit  15  is fully operational even before the slide  62  is open. 
     The sleeve nut  29  further ensures that during normal operation the tensioning motor  16  cannot and must not turn the emergency actuator assembly  7 . This is possible due to the fact that the tensioning motor  16  makes only a small turn and there is ample play in the sleeve nut  29  between the stops, as illustrated in  FIG. 4 . 
     If in an emergency situation the actuator system  1  must be used to close the slide  62 , the auxiliary trunnion  22  is turned in the opposite direction. Only a few turns are necessary to trigger the emergency release unit  15 . That unit then works as described above, without the motor  9  turning along with it since in this case again the free-wheeling mechanism is activated. 
     In submarine applications, the emergency actuator assembly allows operation of the actuator element for shifting the control device by underwater manipulators or small minisubs. It is thus possible even in the event of a power failure or other control-device problem for instance to open a valve and thus, with the appropriate equipment, to restore access to a borehole or the like. By appropriate switching of the control device in an emergency situation the borehole or extraction site can therefore be secured so as to permit external repair work without endangering the environment. 
     During operation, the advance mechanism can function without engaging the emergency actuator assembly or exposing it to wear, by the interpositioning of the directional clutch unit between the emergency actuator assembly and the advance mechanism. In specific terms, whenever the advance mechanism moves the axially movable actuator element into the shift position, the mechanical movement is not transferred to the emergency actuator assembly. 
     Because the actuator element is to be reset by the control device that is pressure-loaded against the shift direction, and in order to keep the design of the actuator system simple, the advance mechanism can be equipped with at least one motor serving to drive a rotary shaft that is solidly connected to a rotating sleeve pivot-mounted inside the system enclosure and surrounding the rotary shaft, in which case the rotating sleeve can be designed to lock in the direction opposite the direction of advance rotation of the rotary shaft in the system enclosure. 
     To allow the emergency actuator assembly to move the actuator element at least in the shift direction, the clutch unit can be set in the advance direction of rotation, meaning that when the rotary shaft rotates in the advance direction of rotation, the clutch unit disengages both the advance mechanism and the emergency actuator assembly, whereas in the event for instance of a motor failure it is possible for the emergency actuator assembly, by causing the clutch to engage, to turn the rotary shaft in the forward, i.e., advance direction of rotation. 
     As a simple way to cushion the advance mechanism against the pressure load applied by the control device in the direction opposite the shift direction, the rotating sleeve can be provided with a volute buffer spring attached to a stationary circular flange mounted in the system enclosure, permitting the rotating sleeve to be rotationally locked in the direction opposite the rotary advance direction. This ensures the ability of the rotary shaft to turn in the advance direction without being inhibited by the volute buffer spring when extending the actuator element. At the same time any automatic extension of the actuator element into the system enclosure under the pressure applied by the control device against the shift direction will be prevented by the volute spring. The physical stress applied by the pressure load is absorbed by the system enclosure. 
     In order to permit automatic resetting of the actuator element for closing the control device even during a power failure or other problem, the volute spring is equipped with an emergency release unit for resetting the actuator element against the shift direction. As an example, such an emergency release unit would be a tensioning sleeve for the volute spring, pressure-loaded in the relaxation direction, rotatable between a cocked and a release position by means of a tensioning motor and especially a step motor, and releasably held in that cocked position. 
     The emergency release unit can be accommodated in the system enclosure by mounting the tensioning motor inside the enclosure next to the advance mechanism. The tensioning sleeve and the associated volute spring extend in essentially concentric fashion around the rotary shaft within the system enclosure. 
     For as long as electric power is fed to the tensioning motor, it applies a holding force to the tensioning sleeve, counteracted by the pressure load on the tensioning sleeve in the direction of the relaxed position. If the electric power fails or drops, the pressure load will cause the tensioning motor and in particular the tensioning sleeve to turn in the direction of the relaxed position. In a simple design example, the pressure load bearing on the tensioning sleeve in the direction of the relaxed position can be provided by a return spring mounted between the tensioning sleeve and the system enclosure or on any suitable component immovably attached in relation to the system enclosure. It should be noted that this return spring may be employed both for emergency closing and for normal closing operations, i.e., for resetting the tensioning sleeve when the volute spring is to be released. 
     In the simplest case, the immovable component referred to may be a detachable lid mounted at the outlet end of the system enclosure. 
     To permit uncomplicated operation of the emergency actuator assembly by underwater manipulators, small mini-subs or the like, the actuator system can be provided with a rotatable auxiliary trunnion that protrudes from the interior of the system enclosure and that is movably linked to the directional clutch inside the interior. The end of the auxiliary trunnion protruding from the system enclosure may be suitably contoured to fit into a matching manipulating tool. 
     Simple coupling of the clutch unit to the advance mechanism can be obtained by mounting the directional clutch unit on a motor shaft protruding from the motor opposite the rotary shaft. 
     A simple design example of a directional clutch unit would be a free-wheeling gear with coaster mechanism where the gear engages in a drive gear on the auxiliary trunnion. 
     To protect the motor against inadvertent actuation, a slip-ring coupling can be interpositioned between the auxiliary trunnion and the drive gear, preventing the transfer of an excessive torque to the motor. 
     To also permit operation of the emergency release unit via the auxiliary trunnion, i.e. the emergency actuator assembly, a tensioning-motor shaft may be designed to protrude from the tensioning motor opposite the tensioning sleeve and to be movably linked to the auxiliary trunnion. 
     In a simple design example the tensioning-motor shaft may be linked to the drive gear or to the free-wheeling gear. 
     To prevent the tensioning motor from driving, or having to drive, the emergency actuator assembly in reverse during normal operation, overrun protection is provided for instance by means of a sleeve nut connecting a free end of the tensioning-motor shaft to a threaded spindle equipped with a tensioning gear that engages in the drive gear or the free-wheeling gear. 
     In this case as well, the tensioning gear may be provided with a slip-ring coupling to prevent an inadvertent actuation of the tensioning motor. 
     The play or clearance of motion of the sleeve nut may be such that it permits essentially nonrotational axial movement between two stops respectively on the tensioning-motor shaft and the threaded spindle. 
     For secure suspension, the threaded spindle may be pivot-mounted at its end opposite the tensioning-motor shaft. 
     In this configuration it may be considered desirable to pivot-mount the end of the spindle and/or the auxiliary trunnion in a motor cover plate that can be removably attached to the system enclosure. 
     The pivot bearing may be mounted directly in the motor cover or in a spindle-end and/or auxiliary-trunnion bearing box removably attached to the motor cover. 
     To permit possible checking of the motor or rotating spindle, and thus of the actuator element for any torsional misalignment, at least one detector may be installed to monitor the position of the threaded spindle and/or the tensioning-motor shaft and/or the motor shaft. 
     While specific embodiments have been shown and described, modifications can be made by one skilled in the art without departing from the spirit or teaching of this invention. The embodiments as described are exemplary only and are not limiting. Many variations and modifications are possible and are within the scope of the invention. Accordingly, the scope of protection is not limited to the embodiments described, but is only limited by the claims that follow, the scope of which shall include all equivalents of the subject matter of the claims.