Abstract:
An actuating valve has two relay valves connected to a compressed air source and a pneumatic cylinder with two pressure chambers. When one relay valve is actuated, one pressure chamber is pressure-loaded and the other is relieved. Two 3/2 port directional control valves are arranged upstream of the pneumatic cylinder. Two check valves are positioned in branch lines connecting the relay valves and the directional control valves. A control line connects the branch line to the other directional control valve, respectively. The directional control valves are moveable between a first position allowing compressed air to pass and a pressure relief position. When the relay valves are inactive, the directional control valves are in the first position and the relay valves are in a venting position for the branch lines. When one relay valve is actuated, it assumes a position allowing passage of air to the branch line connected to it.

Description:
BACKGROUND OF INVENTION 
     The invention relates to an actuating valve pneumatic cylinder comprising two pressure chambers separated from one another by a piston connected on a piston rod, which actuating valve comprises two 3/2 port directional control valves as relay valves connectable to a compressed air source and further comprises a valve system connected between these directional control valves and the pneumatic cylinder by which upon actuation of one of the two relay valves one of the pressure chambers can be loaded with compressed air and the other pressure chamber can be relieved of pressure via a venting throttle, respectively. 
     It is required in connection with such an actuating valve that after release of the respectively actuated relay valve, the pneumatic cylinder or its piston remains loaded with compressed air on both ends, that upon release of the previously actuated valve no further venting or pressure relief of both pressure chambers occurs, but that instead a positional locking of the pneumatic cylinder is effected, i.e., a bidirectional pneumatic cylinder should be moved by means of preferably manually actuated relay valves into its respective end positions and, upon cancellation of actuation, should be directly stoppable in its advancing movement. 
     This basic task is solved, for example, by a conventional cylinder control by means of a 5/3 port sliding valve that is controllable by two relay valves and has downstream thereof a venting throttle. The relay valves are usually 3/2 port sliding valves. In particular, when employing a 5/3 port sliding valve, this causes sealing problems between the individual valve channels as a result of the significant number of required lip seals. 
     SUMMARY OF INVENTION 
     The invention has the object to provide an actuating valve which does not have the disadvantages which are caused, in particular, by employing a 5/3 port sliding valve. 
     For solving this object, according to the invention a valve system is provided that comprises two 3/2 port directional control valves arranged immediately upstream of the pneumatic cylinder as well as two check valves which are positioned individually in branch lines connecting one of the relay valves with one of the two 3/2 port directional control valves, wherein a control line extending to the other one of the two 3/2 port directional control valves is connected to the branch line, respectively, wherein by means of the control line the two 3/2 port directional control valves can be moved between their compressed air through positions and their pressure relief positions such that—a) for relay valves that are not actuated the 3/2 port directional control valves are in their compressed air through positions while the relay valves are in a position venting the branch lines; while—b) upon actuation of one of the two relay valves, respectively, it assumes a compressed air through position relative to the branch line connected thereto. 
     According to another embodiment, the actuating valve comprises two compressed air connecting channels connectable to a bidirectional pneumatic cylinder comprising two pressure chambers, as well as two externally actuatable relay valves for alternating connection of one of the two compressed air connecting channels to a compressed air source, respectively, and for a simultaneous venting action controlled by a venting throttle of the corresponding other compressed air connecting channel, wherein each connecting channel has arranged upstream thereof a valve unit which is comprised of two valve bodies, respectively, provided with sealing rings, which valve bodies are coaxially arranged relative to one another in valve chambers embodied as stepped bores and between which a restoring spring is provided which loads both valve bodies into their closed positions. 
     A basic principle of the invention resides in that two 3/2 port directional control valves are employed in place of the previously employed 5/3 port sliding valve so that the sealing problems are significantly reduced. 
     According to a further embodiment of the invention, it is proposed that, overall, slide valves are no longer employed for any of the valve units and, instead, so-called seat valves are used. An actuating valve according to the second embodiment is characterized in particular by its compact configuration thus facilitating its manipulation. 
     For reasons of simplification with respect to reference numerals, in the claims reference is being had partially only to one valve system, for example, in  FIG. 3  to the valve system illustrated to the right, because the configuration of the valve system to the left of  FIG. 3  is identical to the valve system illustrated to the right. 
     According to the invention, the actuating valve according to the invention is preferably employed in connection with a bobbin creel for textile machines as set forth herein. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1   a  shows a basic connection diagram of the actuating valve in the rest position. 
         FIG. 1   b  shows the connection diagram in one of the two operating positions. 
         FIG. 2  shows a side view of the actuating valve connected to a bidirectional pneumatic cylinder. 
         FIG. 3  shows a sectional view of the actuating valve. 
         FIG. 4  shows a sectional view according to the arrows IV—IV of FIG.  3 . 
         FIG. 5  shows an enlarged illustration of one of the two valve units of the actuating valve according to the invention. 
         FIG. 6   a  shows an enlarged illustration of a part of the valve housing in section. 
         FIG. 6   b  shows two of the valve bodies outside of the valve housing. 
         FIG. 7  shows in a schematic illustration a side view of a textile machine, for example, a twisting machine, provided in the longitudinal direction of the machine on both sides with work locations and having bobbin creels arranged pivotably on its topside so as to supply the opposed machine sides. 
         FIG. 8  shows a view of two bobbin creels positioned opposite one another in their lower loading position according to a first embodiment of the invention. 
         FIG. 9  shows a modified embodiment relative to FIG.  8 . 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 2  shows a bidirectionally acting pneumatic cylinder  8  with compressed air lines L 6 , R 6 , connected to an actuating valve  23 , opening on the opposite ends. A piston (not illustrated) mounted on the piston rod  8 . 1  can be loaded with compressed air by means of the compressed air connecting line L 6  or R 6  while the opposed cylinder chamber or pressure chamber can be vented via the other line R 6  or L 6 . On the pneumatic cylinder  8  a drag bearing  24  is provided. A further drag bearing  25  is mounted on the piston rod  8 . 1  in order to connect the pneumatic cylinder to two machine parts which are movable relative to one another. 
       FIG. 1   a  shows the actuating valve  23  in the rest position;  FIG. 1   b  shows an operating position in which the piston rod  8 . 1  is being retracted in the direction of arrow f 1  into the cylinder  8 . 
     According to  FIG. 1   a , two relay valves in the form of, for example, manually actuated 3/2 port directional control valves L 1 , R 1 , are connected by means of connecting lines L 2 , R 2  to a compressed air source P. Branch lines L 3 , R 3  are connected to the relay valves L 1 , R 1 ; they contain check valves L 4 , R 4  and extend to two 3/2 port directional control valves L 5 , R 5  which, by means of lines L 6 , R 6 , are connected or connectable to the pressure chambers  8 . 3 ,  8 . 4  of the pneumatic cylinder  8 . A control line L 7  branches off the branch line L 3  between the relay valve L 1  and the check valve L 4  and extends to the 3/2 port directional control valve R 5  in order to adjust, when loading this control line L 7  with compressed air, the 3/2 port directional control valve R 5  against the force of the spring R 8  into the venting position. A control line R 7  serves the same purpose for adjusting the 3/2 port directional control valve L 5  against the force of the return spring R 8 . The relay valves L 1 , R 1  as well as the check valves L 4 , R 4  and the valves L 5 , R 5  are preferably seat valves which have valve bodies provided with sealing rings which can be moved against a spring force into the valve chambers provided with corresponding valve seats for the sealing rings. 
     When actuating the relay valve L 1  by means of the actuating element or key button L 9  in the direction of arrow f 2 , the connection between the line L 2  and the branch line L 3  is realized so that the check valve L 4  is opened and the compressed air can flow via the line L 6  into the pressure chamber  8 . 3 . At the same time, via the control line L 7  branching off the branch line L 3 , the 3/2 port directional control valve R 5  is adjusted in the direction of arrow f 3  into the venting position in which the pressure chamber  8 . 4  is vented via the line R 6  and a venting throttle R 10 . 
     Release of the key button L 9  causes the relay valve L 1  to be returned by the restoring spring L 11  into the rest and venting position illustrated in  FIG. 1   a  so that the control line L 7  is vented and thus the 3/2 port directional control valve R 5  is again returned under the effect of the restoring spring R 8  into its initial position. 
     The actuating valve according to the invention thus combines, when viewed schematically, four separate 3/2 port directional control valves as well as two check valves which are preferably embodied as seat valves and are connected with one another such that, for example, in the case of manual actuation of one of the two relay valves L 1 , R 1 , compressed air can flow into one of the two pressure chambers of the pneumatic cylinder while the other pressure chamber is vented in a defined way by means of a venting throttle so that, upon release of the previously actuated relay valve, the pneumatic cylinder remains loaded on both ends with compressed air and, in this way, a positional locking of the pneumatic cylinder or of its piston is realized. 
     Upon actuation of the relay valve R 1  by means of the key button L 9 , the pressure chamber  8 . 4  is loaded with compressed air while the pressure chamber  8 . 3  is vented via the throttle L 10  correlated with the 3/2 port directional control valve L 5 . 
     The actuating valve  23  illustrated in a preferred configurational embodiment in  FIGS. 3 ,  4 ,  5 ,  6   a  and  6   b  is characterized in that the valve or control elements, described in connection with  FIGS. 1   a  and  1   b , are mounted in a space-saving way in a compact valve module. 
     According to  FIG. 3 , this valve module is comprised of a bottom part  25  as well as a top part  26 . A channel  27  guided through the top part  26  and connectable to a compressed air source P opens into a distribution chamber  28 . In the bottom part  25  two valve bodies  31 ,  31 ′ are supported or guided which can be moved by means of the key buttons L 9 , R 9  against the force of the restoring springs  33 ,  33 ′ into the distribution chamber  28 . 
     The valve body  31  is supported by means of a valve shaft  31 . 1  with formation of an annular gap in a bore  25 . 1  of the valve module bottom part  25  such that the section of the bore  25 . 1  positioned above the valve shaft  31 . 1  is open toward the surroundings, as illustrated in  FIG. 3  for the key button L 9 ; see drive shaft  31 . 1 ′ and bore  25 . 1 ′. 
     A bore section  25 . 4  and a valve chamber  25 . 2  adjoin the bore  25 . 1 ; a sealing ring  31 . 2  of the valve body  31  supported on both sides is sealingly guided in the valve chamber upon actuation of the key button R 9 . The diameter of the bore section  25 . 4  is greater than the diameter of the valve chamber  25 . 2  such that the sealing ring, when the relay valve is not actuated, is arranged such in the bore section  25 . 4  that laterally past this sealing ring  31 . 2  a connection between the channel  35  and the surroundings is established. The valve chamber  25 . 2  opens, while forming a valve seat  25 . 3 , into the distribution chamber  28 . A channel  35  adjoins laterally the valve chamber  25 . 2  above the sealing ring  31 . 2 . 
     A sealing ring  31 . 4  of the valve body  31  is pressed in the rest position by the spring  33  against the valve seat  25 . 3 , as illustrated in  FIGS. 3-6  for the valve body  31 ′. 
     A stepped bore adjoins the channel  35  according to  FIGS. 4 and 6   a  and receives a twin valve unit comprised of a first lower valve body  36  and a second upper valve body  38 . This stepped bore has a guide section  39  adjoining the channel  35 , wherein a valve chamber  41  adjoins the guide section while forming a valve seat  40 . By means of an additional valve seat  42  a valve chamber  43  adjoins the valve chamber  41 , wherein the valve chamber  43  is connected by means of a valve seat  44  to the valve chamber  45  into which a venting channel  46  opens laterally. 
     The valve body  36  has a valve shaft  36 . 1  guided in the guide bore  39  which has about its circumference several axial slots  36 . 2 . On the topside of the valve shaft  36 . 1  a sealing ring  36 . 3  is provided which in the rest position is forced by the restoring spring  36 . 4 , supported between the lower and upper valve bodies  36 ,  38 , against the valve seat  40 . 
     The valve body  38  has a valve shaft  38 . 1  guided in the valve chamber  41  which is essentially configured as a hollow cylinder with lateral wall openings  38 . 2  and whose interior is in communication with the valve chamber  41 . This valve body  38  supports a first lower sealing ring  38 . 3  for cooperation with the valve seat  42  as well as a second upper sealing ring  38 . 4  for cooperation with the valve seat  44 . The valve body  38  is also provided with a piston  38 . 5  which is sealingly guided in the valve chamber  45 . 
     The actuating valve contains, in addition to the valve unit explained in connection with the valve bodies  31 ,  36 , and  38 , a second valve unit which is configured symmetrically thereto whose details are illustrated to the left in FIG.  3  and have the same reference numerals as the valve unit illustrated to the right in  FIG. 3 , wherein the reference numerals for the left valve unit are marked with an apostrophe. 
     The two valve units are connected to one another in accordance with the control lines L 7 , R 7  of  FIGS. 1   a  and  1   b  by control channels  47  and  47 ′ connected to the channels  35 ,  35 ′. In accordance with  FIGS. 3 and 4 , the control channel  47  branching off the channel  35  has a connecting channel  47 . 1  extending transversely through the valve module top part  26  which opens with its mouth  47 . 2  into the valve chamber  45 ′ above the valve member  38 ′. 
     By pressing down the key button R 9 , the valve unit to the right in  FIG. 3  is actuated. In this way, the sealing ring  31 . 4  of the valve body  31  is lifted off the valve seats  25 . 3  facing the distribution chamber  28  so that compressed air can flow into the channel  35  and the guide bore  39 . In this way, the lower valve body  36  is moved upwardly against the force of the restoring spring  36 . 4 , and the sealing ring  36 . 3  is lifted off the valve seat  40  so that the compressed air flows through the radial slots  36 . 2  into the valve chamber  41  and thus also through the wall openings  38 . 2  of the valve shaft  38 . 1  into the valve chamber  43 . This valve chamber  43  is connected by means of a lateral opening  43 . 1  to a connecting channel  50  to which is connected the compressed air connecting line R 6  extending to the pressure chamber  8 . 4  so that the compressed air can flow into this compressed air pressure chamber  8 . 4 . 
     In order to be able to move the piston  8 . 2  of the pneumatic cylinder unit  8 , it is required to vent the other pressure chamber  8 . 3 . This is realized in such a way that compressed air can flow into the valve chamber  45 ′ above the valve body  38 ′ via the control channel  47 , the connecting channel  47 . 1  adjoining it, and the mouth  47 . 2  so that the valve body  38 ′ is pressed downwardly causing the sealing ring  38 . 4 ′ to be pushed away from its valve seat  44 ′. In this way, via the connecting lines L 6  and  50 ′ a connection between the pressure chamber  8 . 3  and the section of the valve chamber  45 ′ positioned underneath the sealing piston  38 . 5 ′ is produced so that the pressure chamber  8 . 3  is vented by the venting channel  46 ′ connected to the valve chamber  45 ′. 
     In order to prevent a sudden pressure loss in the pressure chamber  8 . 3 , a venting throttle (not illustrated) corresponding to the throttle L 10  of  FIGS. 1   a  and  1   b  is provided in the venting channel  46 ′. The same holds true also for the venting channel  46 . 
     After releasing the key button L 9 , the lower valve body  36  is pushed downwardly by the restoring spring  36 . 4  so that the sealing ring  36 . 3  is pressed against the valve seat  40 . 
     Since after releasing the key button R 9  the compressed air supply, supplied via the venting channel system  47 ,  47 . 1  and  47 . 2  to the valve chamber  45 ′ above the valve body  38 ′, is canceled, this valve body  38 ′ is again moved upwardly by the restoring spring  36 . 4 ′ so that the sealing ring  38 . 4 ′ is pressed against the valve seat  44 ′. 
     In this way, the positional locking of the pneumatic cylinder  8 , described above in connection with  FIGS. 1   a  and  1   b , is effected. 
     In order to be able to move, on the one hand, the valve body  36  of the valve unit illustrated to the right and thus the sealing ring  36 . 3  against the valve seat  30  and, on the other hand, to move the valve body  38 ′ of the valve unit illustrated to the left in the upward direction and thus move the valve seal  38 . 4 ′ into a contact position against the valve seat  44 ′, it is necessary to relieve the compressed air cushion which is present within the channel system  35 ,  47 ,  47 . 1 , and  47 . 2 . For this purpose, the venting system between the channel  35  and the environment is provided which has been described above in connection with the key button L 9  in the rest position. 
     The textile machine  1  only schematically illustrated in  FIG. 7  is, for example, a twisting machine provided in the longitudinal direction on both sides with twisting spindles. According to  FIG. 7 , the bobbin creel  2  correlated with the left machine side is shown in its upper operating position. The bobbin creel  2  correlated with the right side of the machine is illustrated in its lower loading or supplying position. According to  FIG. 8 , each bobbin creel  2  is configured as a twin bobbin creel and provided or loaded with four feed bobbins Sp so that two neighboring twisting spindles can be served by a single bobbin creel, respectively. The feed bobbins Sp are so-called single feed bobbins for the outer thread of the twisting process. 
     According to  FIG. 7 , each bobbin creel  2  is fastened by means of a holder  4  on the topside of the twisting machine  1  on a support  3  extending in the longitudinal direction of the machine. On this holder  4 , which forms the stationary part of a four-bar linkage, two further opposed members  5  and  6  are pivotably connected, wherein at their ends, opposite the holder  4 , the fourth member  7  of the four-bar linkage is pivotably connected. 
     For reasons of stability, the holder  4  forming the stationary member of the four-bar linkage is comprised of two frame parts  4 . 1  positioned at a spacing to one another. Between them, an upper axle  4 . 2  and a lower axle  4 . 3  are supported. The four-bar linkage member  7  is box-shaped with two opposed sidewalls  7 . 1  which are connected to one another by an end wall  7 . 4  and between which an upper axle  7 . 2  and a lower axle  7 . 3 , illustrated in dashed lines, are supported. 
     On the two upper axles  4 . 2  and  7 . 2 , the four-bar linkage member  5  is pivotably supported. The four-bar linkage member  6  that is supported on the lower axles  4 . 3  and  7 . 3  has the shape of a box profile for reasons of stability. 
     In the embodiment according to  FIG. 8 , two adjacently positioned pneumatic cylinders  8  as well as a pneumatic spring  9  arranged between these two pneumatic cylinders  8  are supported so as to be pivotable on the axles  4 . 3  and  7 . 2  (see FIG.  9 ). The pneumatic spring  9  is comprised, by definition, of a cylinder into which a piston rod  9 . 1 , optionally with a piston connected thereto, can be moved for pre-tensioning the gas volume contained in the closed cylinder chamber. 
     Each pneumatic piston  8  is preferably controlled by an actuating valve of the above described kind. 
     According to  FIG. 9 , only one pneumatic cylinder  8  is pivotably supported on the axles  4 . 3  and  7 . 2  adjacent to the pneumatic spring  9 . 
     Each pneumatic cylinder  8  is a so-called bidirectional pneumatic cylinder loaded at both ends with compressed air; it contains two compressed air chambers which are separated from one another by a piston and can be supplied alternatingly with compressed air. 
     According to  FIG. 8 , a frame  11  is attached to the end wall  7 . 4  forming a securing plate; the frame supports on both sides two receiving members  12  for feed bobbins Sp. 
     On the front side of each center stay  11 , an actuating valve is provided which is connected by compressed air lines (not illustrated), on the one hand, to a compressed air source and, on the other hand, to the two compressed air chambers of the pneumatic cylinder  8 . 
     For the purpose of pivoting the bobbin creel downwardly into the lower position illustrated in  FIG. 7  for loading the bobbin creel  2  with new feed bobbins Sp, the compressed air cylinder  8  is loaded with compressed air such that its piston rod  8 . 1  (see  FIG. 7 ) with the piston attached thereto is retracted into the cylinder chamber. At the same time, the pneumatic spring  9  is pretensioned by retraction of the piston rod  9 . 1 . 
     After completion of the loading or supply process, the piston rod  8 . 1  is again moved out of the cylinder by means of a corresponding valve actuation so that the bobbin creel  2 , assisted by the pneumatic spring  9 , is pivoted into its upper position. 
     While specific embodiments of the invention have been shown and described in detail to illustrate the inventive principles, it will be understood that the invention may be embodied otherwise without departing from such principles.