Abstract:
A hydraulic swivel has a case defining a substantially cylindrical interior and a first access port defined in a side thereof, the first access port providing a path for fluid communication between an interior and an exterior of the case. A spool occupies the interior of the case, the spool and the case together defining a first circumferential channel such that the access port is in fluid communication with the channel regardless of the rotational relationship between the case and the spool, and wherein the spool defines a first interior passageway, the first interior passageway having a port connecting to the first circumferential channel. An actuator occupies at least a portion of the first interior channel selectively blocking and enabling fluid communication between the first circumferential channel and the first interior passageway and therefore selectively blocking and enabling fluid communication between the access port and the first interior passageway.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the priority of U.S. Provisional Patent Application No. 61/426,410, entitled “HYDRAULIC SWIVEL,” filed Dec. 22, 2010, the contents of which are hereby incorporated by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    This disclosure relates to hydraulic systems in general and, more specifically, to rotatable hydraulic connections. 
       BACKGROUND OF THE INVENTION 
       [0003]    Hydraulic systems are ubiquitous in the modern age. Nearly every machine in which a linear actuation or force is needed or can be used to produce a desired end can be constructed with hydraulics. Hydraulic motors can be used to move equipment. Hydraulic actuators can be used to control connected mechanical systems. Additionally, hydraulic pumps can easily be driven from power take off (PTO) devices that are commonly built into industrial transmissions. 
         [0004]    Although hydraulic systems provide versatility and utility, sometimes the configuration a vehicle or machinery employing the hydraulic system creates issues with connecting the appropriate hydraulic lines and circuits. This is particularly so where the vehicle articulates or swivels in order to do its job. Hydraulic hoses can only be twisted or stressed a certain amount before they will break. Lengthening the hoses to accommodate a large degree of rotation can place slack hose in danger of being damaged. Such damage not only leads to costly repairs, but can also be dangerous due to the high pressures and temperatures of hydraulic fluid. 
         [0005]    What is needed is a device and method that addresses the above, and related, issues. 
       SUMMARY OF THE INVENTION 
       [0006]    The invention of the present disclosure, in one aspect thereof comprises a hydraulic swivel that has a case defining a substantially cylindrical interior and having a first access port defined in a side thereof, the first access port providing a path for fluid communication between an interior and an exterior of the case. The swivel has a spool occupying at least a portion of the cylindrical interior of the case, the spool and the case together defining a first circumferential channel inside the case such that the access port is in fluid communication with the first circumferential channel regardless of the rotational relationship between the case and the spool, and wherein the spool defines a first interior passageway, the first interior passageway having a port connecting to the first circumferential channel. A first actuator occupies at least a portion of the first interior channel and selectively controls fluid communication between the first circumferential channel and the first interior passageway. In some embodiments, the swivel implements a two port, two position hydraulic control valve with the access port and the second interior passageway providing the two ports of the control valve. In some embodiments the swivel implements a pressure controlling valve, a flow controlling valve, a load controlling valve, or a directional control valve. Some embodiments comprise a hydraulic valve attached in a fixed relationship to the outside of the case. 
         [0007]    In some embodiments the swivel also includes a second circumferential channel defined by the case and the spool, the second circumferential channel having a port to the first interior channel. Fluid communication may be selectively enabled by the actuator between the first circumferential channel and the first interior channel and between the second circumferential channel and the first interior channel. 
         [0008]    In some embodiments, the swivel includes second and third circumferential channels defined by the case and the spool, and a second and third interior channel defined by the spool and having a port to the second and third circumferential channels, respectively. The first interior channel has a port to the second and third circumferential channels. Fluid communication is enabled by the actuator between the first and third circumferential channels when fluid communication between the first and second circumferential channels is blocked, and fluid communication between the first and third circumferential channels is blocked whenever fluid communication between the first and second channels is enabled. In some embodiments, this swivel may implement a three-port, two-position control valve in a hydraulic circuit where the access port and the second and third interior channels provide the three ports of the control valve. 
         [0009]    In some embodiments, the case is substantially smooth on its interior and the spool has at least one groove cut thereinto to define the first circumferential channel. In other embodiments, the spool is substantially smooth on an outer surface thereof and the case has at least one groove cut into its interior to define the first circumferential channel. The actuators may comprise a hydraulic solenoid. The hydraulic solenoid is controlled from an end of the spool that rotates independently of the case. In other embodiments, the actuator comprises a plunger that may be actuated from an end of the spool that rotates independently of the case. 
         [0010]    The invention of the present disclosure, in another aspect thereof, comprises a device having a case in a cooperatively fitted relationship with an interior spool such that the spool may freely rotate within the case. An access port is defined in the case and provides for fluid communication between an exterior and an interior of the case. First, second, and third channels are defined between the case and spool such that the access port is in fluid communication with the first channel regardless of the rotation of the spool with respect to the case. A first interior pathway is defined in the spool and has a fluid connection with the first, second, and third channels. A second interior pathway is defined in the spool and has a fluid connection with the second channel. A third interior pathway is defined in the spool and has a fluid connection with the third channel. The device has a selective actuator within the first channel that selectively allows fluid communication between the access port and the second interior pathway and third interior pathway, respectively, by selectively blocking fluid communication between the first interior passageway and the second and third channel, respectively. In some embodiments, the device is configured as a three port, two position hydraulic control valve in a hydraulic circuit, with the access port and the second and third interior pathway providing the three ports of the control valve. 
         [0011]    In some embodiments, the actuator comprises and electronically actuated hydraulic solenoid. In other embodiments, the actuator may be a plunger assembly. In some embodiments, the case is substantially smooth on the interior thereof and a plurality of grooves are cut into the spool to at least partially define the first, second, and third channels. In other embodiments, the spool is substantially smooth on an exterior surface thereof and a plurality of grooves are cut into the interior of the case to at least partially define the first, second, and third channels. 
         [0012]    The invention of the present disclosure, in another aspect thereof, comprises a method including providing cylindrical case with open ends and an access port in a side thereof, and providing a cylindrical spool sized to fit at least partially into the cylinder and having first, second, and third channels cut longitudinally thereinto and accessible from at least one end thereof. The method includes defining first, second, and third circumferential channels between the cylinder and the spool such that the access port is in fluid communication with the first channel regardless of the degree of rotation between the case and the spool. The method also includes creating three respective ports in the spool connecting the first longitudinal channel to the first circumferential channel, the second circumferential channel, and the third circumferential channel, creating a port in the spool between the second longitudinal channel and the second circumferential channel, and creating a port in the spool between the third longitudinal channel and the third circumferential channel. A selective actuator is provided situated at least partially in the first longitudinal channel that operates to selective block any connection between the first circumferential channel and the second circumferential channel and between the first circumferential channel and the third circumferential channel. 
         [0013]    In some embodiments, the method includes constructing a hydraulic circuit using the access port and the second and third longitudinal channels as three ports of a three port, two position hydraulic control valve, and using the actuator to control the valve. Defining first, second, and third circumferential channels further may comprise cutting channels into an exterior surface of the spool. In other embodiments, defining first, second, and third circumferential channels further comprises cutting channels into the interior of the case. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]      FIG. 1  is a perspective view of one embodiment of a hydraulic swivel according to aspects of the present disclosure. 
           [0015]      FIG. 2  is top view of the swivel of  FIG. 1 . 
           [0016]      FIG. 3  is a bottom view of the swivel of  FIG. 2 . 
           [0017]      FIG. 4  is a side cutaway view taken along the line AA of  FIG. 2 . 
           [0018]      FIG. 5  is a side cutaway view taken along the line BB of  FIG. 2 . 
           [0019]      FIG. 6  is a side cutaway view taken along the line CC of  FIG. 2   
           [0020]      FIG. 7  is an end cutaway view of the device of  FIG. 1  taken along the line ZZ. 
           [0021]      FIG. 8  is a side cutaway view of another embodiment of a hydraulic swivel according to aspects of the present disclosure. 
           [0022]      FIG. 9  is a circuit diagram of a circuit that may be implemented by various embodiments of the present disclosure. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0023]    Referring now to  FIG. 1 , a perspective view of one embodiment of a hydraulic swivel according to aspects of the present disclosure as shown. One function provided by the hydraulic swivel  10  is to pass hydraulic connections unimpeded through a swiveling joint. An additional function of the hydraulic swivel  10  is to provide a functioning hydraulic circuit within the swivel. In the present embodiment, a substantially cylindrical case  100  contains a substantially cylindrical spool  200 . The case and the spool are arranged in a relationship to one another such that the case  100  and spool  200  may swivel or rotate up to 360° or more with respect to each other. 
         [0024]    Referring now also to  FIGS. 2 and 3 , which are bottom and top views, respectively, of the swivel  10 , additional exterior componentry will be described. The present embodiment provides a number of hydraulic access ports  110 ,  120 ,  130 ,  140 ,  150 , and  160  arranged at various radial and longitudinal locations on the case  100 . The hydraulic access ports  110  through  160  provide fluid communication between the exterior and interior of the case  100 . In the present embodiment, in order to supply hydraulic pressure into the swivel  10 , a high-pressure input  380  is provided, as can be seen in  FIG. 1 . In  FIG. 3 , the high-pressure input is occluded by a hydraulic solenoid  480 . A low-pressure return channel  370  may also be provided in the spool  200 . In the present embodiment, additional hydraulic access ports hydraulic valves  560 ,  570  are provided externally on the case  100 , and may provide for additional functionality on the case itself. 
         [0025]    In addition to a high-pressure input solenoid  480 , actuators are provided that are accessible externally to the cylinder  10  that change the hydraulic circuit inside the cylinder electronically. In the present embodiment, four actuators can be seen in  FIG. 2  on the upper end of the cylinder  10 . Two additional actuators  450  and  460  can be seen on the bottom end of the cylinder end in  FIG. 3 . 
         [0026]    Referring now also to  FIG. 4 , a cutaway view of the cylinder  10  is shown as taken along line AA in  FIG. 2 . In the present embodiment, the spool  200  defines a number of channels on the exterior thereof. These channels may be circumferential and circumscribe the spool  200  laterally. In the present embodiment, circumferential channels  210 ,  220 ,  230 , and  240  correspond to the hydraulic access ports  110 ,  120 ,  130 , and  140 , respectively. Circumferential channels  250  and  260  correspond to hydraulic access ports  150  and  160 , respectively. It will be appreciated that in the configuration shown in the various views of the present disclosure, that regardless of the degree of rotation between the case  100  and spool  200 , that the respective hydraulic access port will always be in fluid communication with its respective circumferential channel. 
         [0027]    The present embodiment also provides for a high-pressure circumferential channel  270  and a low-pressure circumferential channel  280 . A second low-pressure circumferential channel  290  is provided near the bottom of the device  10 . As will be more apparent from views described more fully below, these high and low-pressure circumferential channels will be selectively connected to the various functional channels  210 ,  220 ,  230 ,  240 ,  250 , and  260 , to implement various hydraulic circuitry and functionality. From the present viewpoint of  FIG. 4 , it can be seen that an actuator, here a solenoid  420 , inserts into an interior channel  320  defined in the spool  200 . The channel  320  provides a port  321  connecting to circumferential channel  220 . The interior channel  320  also connects to the low-pressure circumferential channel  280  via port  322 . The interior channel  320  connects to the high-pressure channel  270  by port  323 . The actuators of the present disclosure may be commercially available electronically controlled hydraulic solenoids and operative to block or allow access between various ports. Other actuator types are within the scope of this disclosure including, but not limited to a pressure controlling valve, a flow controlling valve, a load controlling valve, or a directional control valve. Mechanically, these may comprise spools, plungers, stoppers, gates, seals, and/or other mechanical implements. 
         [0028]    In this case, the actuator  420  blocks or allows access between ports  321  and  322 , or between the ports  321  and  323 . In this manner, the circumferential channel  220  will have a fluid connection to either the low-pressure return channel  322  or the high-pressure input channel  323 . In this way, a device connected to the swivel  10  via the hydraulic port  120  will receive either high or low pressure, depending upon the activation state of the solenoid  420 . Additionally, due to the design of the swivel  10 , the hydraulic access port  120  will receive the appropriate high or low pressure regardless of amount of rotation between the case  100  and the spool  200 . 
         [0029]    The actuator  440  operates in much the same way as the actuator  420 . The actuator  440  is inserted into an interior longitudinal channel  340  that connects to circumferential channel  240  via port  341 . The interior channel  340  also connects to the low-pressure circumferential channel  280  via port  342  and to the high-pressure circumferential channel  270  via the port  343 . The actuator  440  is electronically activated and will allow access between the port  341  and  342  or between the port  341  and  343 . Thus the circumferential channel  240  will be in fluid communication with the low-pressure circumferential channel  280  or the high-pressure circumferential channel  270 . As with all of the hydraulic access ports of the present disclosure, full rotation is allowed between the case  100  and spool  200  while maintaining the appropriate connection. 
         [0030]    In the present view, a portion of the actuator  430  can be seen inserted into the interior channel  330 , shown in dotted line. The interior channel  330  connects to the circumferential channel  230  via port  331 . As before, a port  332  and  333  are provided for connecting to the low-pressure circumferential channel  280  and  270 , respectively. As before, the actuator  430  provides selective access between the port  331  and  332 , or between the port  331  and  333 . Thus, high or low pressure may be provided to hydraulic access port  130 . 
         [0031]    Shown in dotted line is interior channel  360  into which actuator  460  is inserted. Here it can be seen that the circumferential channel  260  may be connected to the low-pressure circumferential channel  290  or to channel  260  via ports  361  and  362 , respectively. Not shown in this view is an internal connection between the interior channel  360  and another high-pressure interior channel within the spool  200 . The interior channel  360 , being connected to an interior high-pressure channel, the circumferential low-pressure channel  290  and the circumferential channel  260  allows the actuator  460  to selectively connect the channel  260  to either a high or low hydraulic pressure. The hydraulic access port  160  is always in fluid connection with the circumferential channel  260 . Therefore, the solenoid  460  controls the hydraulic connection to the hydraulic access port at  160 . 
         [0032]    It can also be appreciated from the present view, that the circumferential channels may be accessed by more than one hydraulic access port. For example, the valve  560  is connected to both the circumferential channel  280  and the circumferential channel  220 . As previously described, the actuator  420  can selectively connect the circumferential channel  220  to high or low pressure. The additional valve  560  allows for additional hydraulic control to be provided that on the outside of the case  100 . In one embodiment, the valve  560  implements a load balancing function. 
         [0033]    Referring now also to  FIG. 5 , a side cutaway view of the swivel  10  is seen as taken along the line BB of  FIG. 2 . Here actuator  410  can be seen seated in interior channel  310  which connects to circumferential channel  210 , low-pressure circumferential channel  280 , and high-pressure circumferential channel  270  via ports  311 ,  312 , and  313 , respectively. The actuator  410  functions in the same manner as the previously described actuators in allowing fluid access to the port  311  and  312  or between port  311  and  313 . In this manner, the hydraulic pressure to circumferential port  210  can be selectively electronically controlled by the actuator  410 . Hydraulic access port  110  is in continuous fluid communication with the circumferential channel  210 . Shown in dotted line is interior channel  350  connecting to circumferential channel  250  via port  351  and to low-pressure circumferential channel  290  via port  352 . The actuator  450  provides selective access for the circumferential channel  250  to low-pressure circumferential channel  290  or to an interiorly connected high-pressure channel not shown. 
         [0034]    Referring now to  FIG. 6 , a side cutaway view of the swivel  10  is shown as taken along the line CC of  FIG. 2 . An interior channel  370  can be seen that is cut longitudinally into the spool  200  and runs from the bottom of the spool to proximate the low-pressure circumferential channel  270 . The channel  370  and the channel  270  are connected via port  373  in the present embodiment. The channel  370  also connects to low-pressure circumferential channel  290  via port  374 . In the present embodiment, the function of the low-pressure channel  370  is to provide a low hydraulic pressure or a return line to the circumferential channels  270  and  290 . As previously described, the circumferential channels  210 ,  220 ,  230 ,  240 ,  250 , and  260  may be selectively connected to either the low-pressure channel  270  or the low-pressure circumferential channel  290 . And this way, the various ports may be selectively connected to a low hydraulic pressure. An interior channel  380  is provided in the spool  200  for providing high hydraulic pressure. The channel  380  connects to the high-pressure circumferential channel  280  via port  383 . As previously described, the various ports may be selectively connected to the high-pressure circumferential channel  280  and therefore to the high-pressure interior channel  380 . In the present embodiment, an actuator  480  is provided for selectively enabling or disabling the high-pressure hydraulic channel  380 . In the present embodiment, a connection into the channel  380  is provided via port  385 . It may be noted that in the view of  FIG. 1 , the location of the port  385  and the solenoid  480  are reversed correspond to that of  FIG. 6 . 
         [0035]    Referring now to  FIG. 7 , an end cutaway view of the swivel  10  taken along the line ZZ of  FIG. 6  is shown. Here the interior channels  350  and  360  are shown fluidly coupled to high-pressure channel  380  via ports  386  and  385 , respectively. The location of the internal ports  385 ,  386  between the channel  360  and  380 , and  350  and  380 , allows fluid communication to be selectively controlled by actuators  450  and  460 , respectively. 
         [0036]    Referring now to  FIG. 8 , another embodiment of hydraulic swivel  700  according to aspects of the present disclosure is shown. The view of  FIG. 8  is that of a side cutaway view. In this embodiment a case  100  once again provided with an internal spool  200 . The case  100  and spool  200  are able to freely rotate with respect to one another. High and low-pressure interior channels (not shown) may also be provided in the spool  200 . It will be noted that the in the present embodiment, the exterior surface of the spool  200  is substantially smooth while the interior surface of the case  100  has a number of circumferential channels  721  cut therein. In the present embodiment, rather than controlling access between the various circumferential channels using a network of interior channels and solenoids, a plunger  730  is provided that is moved longitudinally via actuator  710 . The plunger  730  may be sliding or rotating or motive in some other way. Hydraulic access ports  720  are provided to certain of the circumferential channels  721  to provide an external connection to the case  100 . As before, by selective interconnection of the various circumferential channels, the pressure seen at the various circumferential channels  721  and access ports  720  may be controlled from within the spool  200 . In one embodiment, the device of  FIG. 8  implements a 4-way, three position hydraulic valve. In such an embodiment the plunger moves to expose various ports to high or low pressure on demand. 
         [0037]    Referring now to  FIG. 9 , one example of a hydraulic circuit  900  that may be implemented within one or more embodiments of the hydraulic swivels of the present disclosure is shown. In the present embodiment, the circuit  900  provides hydraulic power to a drive motor  902 , as well as actuators  904  and  906 . As another example, a steering cylinder  908  is also controlled and powered by the circuit  900 . 
         [0038]    In the present embodiment, a plurality of three port, two position hydraulic control valves  910 ,  912 ,  914 , and  916  are provided. The actuators  410 ,  420 ,  430 , and  440 , and the associated hydraulic channels they control replicate the functionality of three port, two position hydraulic control valve within the hydraulic swivels previously described. Therefore, in the present circuit, the high-pressure line P may be connected to the high-pressure channel  380  as shown in  FIG. 6 , and the output of the switch  910  can be connected to hydraulic access port  110 . Thus, the actuator  410  will replicate the functionality of the switch  910  within the hydraulic swivel  10  previously described. Actuator  420 , by controlling hydraulic access port  120  can replicate the functionality of the switch  912 . Switches  914  and  916  can be connected in a similar manner. By electronically activating the various solenoids, used as actuators, the functionality as shown in  FIG. 9  can be realized. As shown, the various embodiments of the hydraulic swivel of the present disclosure could also be used to control a drive motor  902 . Here, the output of hydraulic switches  918 ,  920  could be connected to outputs  250  and  260 , respectively. The switches  918  and  920  would then be controlled by actuators  450  and  460 . 
         [0039]    It will be appreciated that  FIG. 9  is only one of a multitude of ways in which the hydraulic swivels of the present disclosure could be employed. It is also understood that a hydraulic swivel constructed according to the present disclosure would not necessarily have the same number of hydraulic access ports nor the same internal circuit as shown. The embodiments described are meant only to serve as examples of the concepts of the present disclosure. It will also be appreciated that the case  100  and spool  200  will feature various seals and retainers, as needed, in order to function within specification. The components may be constructed by casting or machining. It will be appreciated that, although the functionality provided within the swivels is complex, the components can be machined with relatively straight forward cutting equipment and other tools. 
         [0040]    Thus, the present invention is well adapted to carry out the objectives and attain the ends and advantages mentioned above as well as those inherent therein. While presently preferred embodiments have been described for purposes of this disclosure, numerous changes and modifications will be apparent to those of ordinary skill in the art. Such changes and modifications are encompassed within the spirit of this invention as defined by the claims.