Patent Publication Number: US-6220142-B1

Title: Manually operated emergency control actuation device

Description:
FIELD OF THE INVENTION 
     The present invention relates to an operation actuation device for a hydraulically controlled actuator, especially for its emergency operation. A housing incorporates a fluid container which can be connected through one connection point to the actuator and through another connection point to a hydraulic supply circuit of the actuator. A separating piston is guided longitudinally slidably within the fluid container by a manually operable adjusting device. The piston includes a control device controlling a through-flow opening connecting the connection points with one another. 
     BACKGROUND OF THE INVENTION 
     When a breakdown or disruption of the hydraulically controlled actuator, generally in the form of a hydraulically operable working cylinder, occurs, for example as a result of current interruption, the actuator can usually no longer be operated. Those occurrences can lead to dangerous disturbances, especially in areas relevant to technical security and/or safety, such as in nuclear power plants or the like. Conventionally, in such operation emergency situations, separate and independent emergency operation systems are activated. However, these emergency operation systems are costly to manufacture and set up, and generally are located so far removed from the site of disturbance that the emergency operation cannot be directly monitored by the operator. 
     DE 33 44 132 C2 discloses an operation device for a hydraulically controlled actuator which has a housing incorporating a fluid container connected through one connection point to the actuator and through another connection point to a supply circuit. Within the fluid container, a separating piston is guided longitudinally slidably by a manually operable adjusting device in the form of a pump handle. The pump handle cooperates with a mechanically working control device working separately in the form of a sliding piston to generate a through-flow opening connecting the fluid connection points with one another. 
     When this known arrangement is provided for emergency actuation of the hydraulically controlled actuator, no conclusions can be derived from the setting of the pump handle regarding whether an operationally secure and/or safe emergency operation has taken place or not. The known control device in the form of the longitudinally movable sliding piston is controlled exclusively by the fluid pressure, leading to erroneous control of the known control device and independent of the setting of the separating piston controlled by the pump handle. Additionally, because of the plurality of parts in the known solution, it is costly to manufacture. 
     SUMMARY OF THE INVENTION 
     Objects of the present invention are to provide an operation actuation device providing, in disruptive situations, a simple and low-cost system for controlling the hydraulically controlled actuator that is operationally secure and safe and that can be monitored from the outside. 
     The foregoing objects are basically obtained by an operation actuation device for emergency actuation of a hydraulically controlled actuator, comprising a housing having a fluid container with an actuator connection point and a hydraulic circuit connection point. A separating piston is guided for longitudinal sliding movement in the housing between first and second end settings. A manually operable adjusting setscrew is coupled to and controls movements of the piston in the housing. The setscrew is threadedly engaged with the housing and is axially movable relative to the housing to move the piston between the end positions. A through-flow opening in the piston is controlled by a control check valve therein and provides controlled fluid communication between the connection points. The check valve is opened in the first end setting by engagement with a part of the housing and is closed in the second end setting by being spaced from the part of the housing. 
     Since the adjusting device is a setscrew which can be screwed into and out of the housing, the setscrew screwing-in length is determined so that the separating piston cooperating with it can be moved between two end settings. The check valve, operated in the end settings by the separating piston, is mechanically controlled in a pro-active manner, and thus, is operationally secure. The separating piston, through a single, non-repetitive delivery movement of the setscrew, specifically assumes the relevant end setting. Consequently, a mechanically specific coupling between setscrew, separating piston and check valve is generated. Such coupling is exceptionally operationally secure and safe, and consequently, is especially suitable for emergency operation of the actuator. 
     The position of the setscrew, screwed fully in or out, allows the on-site operator an immediate overview of whether or not an effective emergency operation system for the actuator exists. 
     The operation actuation device according to the present invention includes only a few structural parts and consequently can be realized simply and at low cost. Using the manually operable adjusting device, the setting process and consequently the operation of the controlled actuator can be monitored precisely on site by the operator. Erroneous control actions are avoided. With sufficient oil volume stored in the fluid container, external readiness setting of control fluid is not necessary. Fluid control by means of the operation actuation device occurs without leakage, so that an operationally secure and/or safe manual emergency operation is guaranteed. 
     Other objects, advantages and salient features of the present invention will become apparent from the following detailed description, which, taken in conjunction with the annexed drawings, discloses preferred embodiments of the present invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Referring to the drawings which form a part of this disclosure: 
     FIG. 1 is a partial, front elevational view, partially in section, of an actuation device, integrated as a part of a supply circuit in standard operation, according to a first embodiment of the present invention; 
     FIG. 2 is a partial, front elevational view, partially in section, of the actuation device of FIG. 1 in emergency manual operation; and 
     FIG. 3 is a partial, front elevational view, partially in section, of an actuation device according to a second embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The operation actuation device, shown in FIGS. 1 and 2, permits emergency actuation of a hydraulically controlled actuator  10  in the form of a spring-biased hydraulic working cylinder  12 . The operation actuation device is provided with a housing  14 , incorporating a fluid container  16  connected through one connection point  18  to actuator  10  and through another connection point  20  to a hydraulic supply circuit, indicated in its entirety with  22 , for actuator  10 . Within fluid container  16  a separating piston  26  is guided for longitudinal sliding movement by means of a manually operable adjusting device  24 . The piston incorporates a control device  28  controlling a through-flow opening  30  connecting connection points  18  and  20  with one another. 
     The manually operable adjusting device  24  comprises a setscrew  32  which can be screwed into and out of housing  14 . The possible screwing-in length is determined in such a manner that separating piston  26 , cooperating with the adjusting device, is longitudinally slidable between two end settings A and B. Through-flow opening  30  of separating piston  26  has a spring-biased control check valve  34  forming control device  28 , which is opened in one of the end settings A or B and is closed in the other end setting B or A. 
     Setscrew  32  engages with its free end  36  in separating piston  26 . Between this free end  36  and the screwhead  38 , a locknut  40 , with setscrew  32  passing through it, is supported on housing  14 . Housing  14  is configured as a sort of one-screw die  42 , can be screwed by means of corresponding exterior threading into an interior threading according to a universally recognized mounting arrangement for control blocks or the like, and can also be removed therefrom. As explained in greater detail hereinafter, parts  44  and  46  of housing  14  in one end setting A or B control the control device  28  when through-flow opening  30  is opened. 
     As is shown particularly in FIGS. 1 and 2, supply circuit  22  has a hydraulic pump  48 , a pilot valve  50  in the form of an electrically operable 3/2-way valve which can be set back with a spring, as well as a reservoir connection  52 . Both connection points  18  and  20  are connected in a supply line  54  between supply circuit  22  and actuator  10 . Furthermore, separating piston  26  has a centering opening  56 , which serves for the contact-engagement of setscrew  32  and is accessible by means of a frontal journal  58 . Centering opening  56  is closed and sealed by means of a stopper plug  60  with surrounding annual seal joint  62 . 
     Separating piston  26  is guided longitudinally slidably within fluid container  16  where it seals off two container areas  66  and  68  from one another by means of another annular seal  64 . Check valve  34  is guided under control in the embodiment of FIGS. 1 and 2 counter to the spring force over an annular flange  70  projecting in a downward direction, as seen in FIG. 1, and consequently frees the through-flow path to through-flow opening  30 . The blocking path for the blocking check valve  34  then runs parallel to the longitudinal alignment of the possible blocking movement for setscrew  32 . 
     For clarification of the actuating device according to the present invention, its operation is described with reference to FIGS. 1 and 2. 
     When not in operation, as shown in FIG. 1, setscrew  32  is screwed out into its topmost position. Thus, separating piston  26  is positioned at its top abutment formed by annular flange  70 . As already described, the built-in check valve  34  is therefore thrust mechanically counter to its spring force. Consequently, free passage of fluid in either direction is guaranteed through through-flow opening  30 ; and the user in the form of working cylinder  12  can be supplied with pressurized oil by the hydraulic pressure pump  48 , dependent upon the setting of pilot valve  50 . 
     If hydraulic pump  48  is out of order, for example, because of a current interruption, working cylinder  12  is moved automatically into its start setting shown in FIG. 1 by means of its own return spring. Consequently, with a current interruption, multi-way valve  50  is moved into its switch setting shown in FIGS. 1 and 2, in other words hydraulic pump  48  would be blocked from supply line  54 . If at this point setscrew  32  is screwed into housing  14 , check valve  34  is closed to block off the discharge flow through supply line  54  to reservoir connection  52  and consequently to prevent loss of pressurized oil. With this adjusting movement placing separating piston  26  in its bottom end setting B, the fluid stored in container  16  is forced out of container area  68  and pressed into working cylinder  12 , counter to the return force of its spring, so that the arrangement finally assumes its actuated setting shown in FIG.  2 . The setting of setscrew  32 , as shown in FIG. 2, thus shows clearly and without question that emergency actuation has taken place. The control of the operation is consequently very simple and obvious to recognize. Setscrew  32  is provided in this case with exterior threading over its entire exterior circumference that engages in the associated interior threading of housing  14 . 
     A modified second embodiment of the actuation device of the present invention is illustrated in FIG.  3 . This arrangement is described only insofar as the modified embodiment differs considerably from the first embodiment described heretofore. The same number references are used for the same structural parts. 
     In the second embodiment of FIG. 3, standard operation is guaranteed in that separating piston  26  as shown, is arranged in bottom end setting B. With this configuration, the control device for check valve  34  works in reverse, in other words it is controlled by means of its control pin or the like engaging a limited surface of bottom part  46  of housing  14 . With the second embodiment, the standard operation is provided when setscrew  32  is completely screwed in. As opposed to the former description, the emergency operation actuation function would be provided in the second embodiment when setscrew  32  would be screwed out of housing  14  beyond screwhead  38 . Separating piston  26  would be carried upward with it and through-flow opening  30  would be controlled by closing of check valve  34 . The fluid conducted by the force of the spring of actuator  10  into container  68  then allows for emergency actuation of the cylinder in the other direction. Setscrew  32  can also be connected in one piece integral with journal  58 , as well as with stopper plug  60 . The pro-active control of the separating piston in both directions is possibly be means of the design of setscrew  32  with screwhead  38 . 
     Since the present operation actuation device can be constructed modularly, according to the needs of the user, different oil volumes can also be made available. An adaptation thus occurs of the available volume of fluid storage container  16 . The described construction is simple and can be manufactured at low cost. The operation actuation device according to the invention has proven especially advantageous when used with cart conveyor vehicles, especially with fork lifts, where it can be actuated in case of breakdown of the motor so that the operator is able to release the parking brakes. 
     While various embodiments have been chosen to illustrate the invention, it will be understood by those skilled in the art that various changes and modifications can be made therein without departing from the scope of the invention as defined in the appended claims.