Abstract:
A hydraulic flow sensing apparatus is provided. The apparatus includes: a manifold; a hole in the manifold in fluid communication with a fluid pathway; a poppet valve in the hole in the manifold configured to move when fluid in the pathway flows; and a proximity switch configured to detect movement of the poppet valve. A method of operating a hydraulic circuit may also be provided.

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to a hydraulic pump. More particularly, the present invention relates to a hydraulic pump configured to provide hydraulic pressure for a hydraulic tool. 
     BACKGROUND OF THE INVENTION 
     In several industries such as the construction industry or industries where pipelines are used to transport fluid pressurized fluids, very large nuts and bolts are used to fasten jointed pipe members together. For example, large pipes are connected by large pipe flanges and pipe, structural members may also be tightened by the use of large nuts and bolts as well as other structural members, wind generator tower sections, utility poles and a myriad of other applications may use very large nuts and bolts. 
     Large nuts and bolts used in these industrial applications require high amounts of torque to be properly tightened. As result, large amounts of torque is also required to loosen these large fasteners. Because of the high torque requirements needed to tighten or loosen these large fasteners it would be impractical to use mechanical torque wrenches. As such, the industry has turned to the use of hydraulic torque wrenches which are capable of generating thousands of foot-pounds of torque. These torque wrenches may be driven by a hydraulic pump capable of delivering about 10,000 PSI to the hydraulic torque wrench. These torque wrenches often incorporate a double acting hydraulic cylinder to push a rotary ratchet to apply the torque. 
     A commonly encountered problem with many hydraulic pumps used to drive hydraulic torque wrenches is that a hand pendant is used by the operator to extend and retract the hydraulic cylinder with in the torque wrench. An operator must actuate an actuator on the hand pendant to extend and again actuate the actuator to retract the hydraulic cylinder within the torque wrench. This requires many repeated operations of actuating the actuator for each faster. The operator&#39;s hand may become quickly fatigued. This may become a problem particularly in instances where there are many fasteners that need to be tightened or loosened. Furthermore, requiring repeated operations of actuating the actuator on the hand pendant is slow and not efficient. 
     Accordingly, it is desirable to provide a method and apparatus that allows a fastener to have an appropriate amount of torque applied to it while at the same time not requiring an operator to constantly actuate an actuator in order to provide the appropriate amount of torque. Further, it may be useful to have a pump that will automatically cycle the torque wrench through extending and retracting the hydraulic cylinder contained within the torque wrench while the operator merely actuates a button or other actuator a single time for each faster. It may also be desirable for the pump to not only automatically cycle the wrench to completely tighten or loosen the faster but also shut down when a proper torque is achieved. 
     SUMMARY OF THE INVENTION 
     The foregoing needs are met, to a great extent, by some embodiments in accordance with the present invention, wherein in some embodiments a method and/or apparatus is provided that allows a faster to have an appropriate amount of torque applied to it while at the same time not requiring an operator to constantly actuate an actuator in order to provide the appropriate amount of torque. In some embodiments it may be provided to have a pump that will automatically cycle the torque wrench through extending and retracting the hydraulic cylinder contained within the torque wrench while the operator merely actuates a button or other actuator a single time for each faster. In some embodiments it may be provided for the pump to not only automatically cycle the wrench to completely tighten or loosen the faster but also shut down when a proper torque is achieved. 
     In accordance with one embodiment of the present invention, a hydraulic flow sensing apparatus is provided. The apparatus includes: a manifold; a hole in the manifold in fluid communication with a fluid pathway; a poppet valve in the hole in the manifold configured to move when fluid in the pathway flows; and a proximity switch configured to detect movement of the poppet valve. 
     In accordance with another embodiment of the present invention, a method of operating a hydraulic circuit may also be provided. The method may include: operating a pump to pressurized fluid in the hydraulic circuit; flowing fluid through the circuit in a first direction; moving a first poppet valve to a first position via the flow in the first flow path; moving the first poppet valve to a second position when no flow in the first flow path is detected by the poppet valve; sending a signal to a microcontroller when the poppet valve moves to the second position; moving a flow reversing valve to a reverse flow in at least part of the circuit when the signal is sent to the microcontroller; and opening a dump valve to provide fluid communication between the circuit and a reservoir when neither the first nor second poppet valve detect flow in either the first or second flow paths for a predetermined amount of time. 
     In accordance with yet another embodiment of the present invention, a hydraulic flow sensing apparatus is provided. The apparatus may include: a manifold; a hole in the manifold in fluid communication with a fluid pathway; means for moving when sensing hydraulic fluid flow in the hole in the manifold configured to move when fluid in the pathway flows; and means for detecting movement of the means for moving. 
     There has thus been outlined, rather broadly, certain embodiments of the invention in order that the detailed description thereof herein may be better understood, and in order that the present contribution to the art may be better appreciated. There are, of course, additional embodiments of the invention that will be described below and which will form the subject matter of the claims appended hereto. 
     In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of embodiments in addition to those described and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein, as well as the abstract, are for the purpose of description and should not be regarded as limiting. 
     As such, those skilled in the art will appreciate that the conception upon which this disclosure is based may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front view of a hydraulic pump in accordance with an embodiment of the invention; 
         FIG. 2  is a side view of a hydraulic pump in accordance with an embodiment of the invention; 
         FIG. 3  is a cross-sectional view of a flow sensing the manifold in accordance with an embodiment of the invention; 
         FIG. 4  is a schematic diagram of a hydraulic circuit in accordance with an embodiment of the invention; and 
         FIG. 5  is a schematic diagram of an electrical circuit in accordance with an embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION 
     The invention will now be described with reference to the drawing figures, in which like reference numerals refer to like parts throughout. An embodiment in accordance with the present invention and a hydraulic pump that has an automatic mode configured to turn a fastener to a specified amount of torque with only one continuous actuation of an actuator and turn itself off once that torque level has been achieved. 
       FIG. 1  illustrates a front view of an auto cycle pump  10  in accordance with an embodiment of the invention. The auto cycle pump  10  includes a motor  12  and a pressure regulator  14 . The auto cycle pump  10  includes a roll cage  16  which allows the auto cycle pump  10  to be protected in the event that the auto cycle pump  12  is knocked over or is otherwise dealt a blow. The auto cycle pump  10  includes a retract port  18  and an advance port  20  the retract port  18  and advance port  20  carry hydraulic fluid to an external tool. The auto cycle pump  10  includes a flow sensing manifold  22  upon which the retract port  18  and the advance port  20  are mounted. 
     The auto cycle pump  10  includes a reservoir  24 . The reservoir  24  is sometimes referred to as a tank  24 . In some embodiments in accordance with the invention, the reservoir  24  contains a hydraulic pump not shown in  FIG. 1 . The auto cycle pump  10  includes a hand pendant  26 . The hand pendant  26  permits an operator to operate the auto cycle pump  10 . The hand pendant  26  includes several actuators. For example, the hand pendant  26  may include a manual button or actuator  28  an auto cycle button or actuator  30  and a stop button or actuator  32 . 
       FIG. 2  illustrates a side view of the auto cycle pump  10 . As seen in  FIG. 2 , the cycle pump  10  includes a motor  12  and a power on button  34  which allows an operator to turn the auto cycle pump  10  on or off. The auto cycle pump  10  also includes a power on indicator  36 . In some embodiments, the power on indicator  36  may be a light that illuminates when the auto cycle pump  10  has been turned on by the power on button  34 . The auto cycle pump  10  may also include a power off button  38  which allows an operator to turn off the auto cycle pump  10  by actuating the power button  38 . The auto cycle pump  10  also may include a directional valve  40  and a pressure gauge  42  and pressure regulator valve  128 . The auto cycle pump  10  may also include various other features and components which are well known in the art and will not be explained here and in detail. 
       FIG. 3  illustrates a cross-sectional view of the flow sensing manifold  22  shown in both  FIGS. 1 and 2 . The flow sensing manifold  22  includes and inlet return flow ports or pathways  44  and  46 . The flow sensing manifold  22  also includes oil return ports or pathways  48  and  50 . In some embodiments in accordance with invention, the oil return pathways  48  and  50  allow hydraulic oil or other hydraulic fluid to flow back to the reservoir  24  (shown in  FIGS. 1 and 2 ). The flow sensing manifold  22  also includes two bores  52  and  54  while these bores  52  and  54  referred to as bores they do not necessarily need to be bored into the flow sensing manifold  22 . Other means of making suitable holes can also be used in accordance with some embodiments of the invention. 
     A poppet valve  56  is located in bore  52  and a second poppet valve  58  is located in bore  54 . The first poppet valve  56  includes a square section or body  60 , a nose  62 , and a tail section  64 . A spring  66  urges the poppet valve  56  to a position to the right as shown in  FIG. 3 . A proximity switch  68  is located proximal to the poppet valve  56  and is configured to sense the location of the poppet valve  56 . Specifically, the proximity switch  68  configured to sense the location of the tail  64  of the poppet valve  56 . A second proximity switch  70  is located proximal to the second poppet valve  58 . The second poppet valve  58  contains similar features as set forth above with respect to the first poppet valve  56  and will not be further described herein. Furthermore, one of ordinary skill in the art after reading this disclosure will understand that the proximity switch  70  is configured to sense the location of at least part of the poppet valve  58 . 
     The poppet valves  56  and  58  are configured to fit tightly with in the bores  52  and  54  and are oriented so that they can sense hydraulic fluid flow within the inlet return flow ports or pathways  44  and  46  respectively. Because of the tight fit between the poppet valves  56  and  58  and the bores  52  and  54 , a relatively low amount of flow can be sensed by the poppet valves  56  and  58 . In particular, the nose of the poppet valve  62  and will push the poppet valves  56  and  58  back against their respective spring  66  when the poppet valves  56  and  58  are pushed back against their springs  66 , the proximity switches  68  and  70  will detect the presence of the poppet valves  56  and  58 . Thus, flow with in either of the two inlet return flow pathways  44  and  46  can be sensed by the proximity switches  68  and  70  via the poppet valves  56  and  58 . 
     The proximity switch  68  is attached to the flow sensing manifold  22  via a connecting nut  74 . The proximity switch  68  is connected to a cable  76  that is terminated with a plug  78 . The plug  78  can allow signals from the proximity switch  68  to be inputted into an electronic circuit. In some embodiments of the invention, the signals will be inputted into a microcontroller which will be described further below. The proximity switch  70  is configured similarly to proximity switch  68 . As shown, the proximity switch  70  is connected to the flow sensing manifold  22  via a connecting nut  82 . The proximity switch  70  is connected to a cable  84  terminated by a plug  86 . Similar to as discussed above with respect to proximity switch  68 , the proximity switch  70  can also have its input sent to a microcontroller or any other desired electronic circuit. 
       FIG. 4  illustrates a hydraulic circuit  88  in accordance with some embodiments of the invention. The hydraulic circuit  88  is a schematic representation of the hydraulic configuration used in the auto cycle pump  10 . The hydraulic circuit  88  includes a reservoir  90 . The reservoir  90  may also be referred to as a tank  90 . When hydraulic fluid or oil is drawn up from the reservoir  90  it passes through a filter  92 . The hydraulic fluid is drawn up from the reservoir  90  due to pressure (or suction) generated by a pump  94 . The pump  94  is operated by a motor  96  the motor  96  is connected to the pump  94  via a shaft  98 . The motor  96  may receive power from a variety of ways such as but not limited to compressed air, electricity, burning of a fossil fuels or any other suitable source of power. 
     The hydraulic circuit  88  may include a system relief valve  100  which provides a pathway for hydraulic fluid coming from the pump  94  to reenter the reservoir  90  if a pressure reaches undesirable level. However the pressure relief valve  100  is normally in the position as shown in  FIG. 4  and does not provide a pathway back to the hydraulic reservoir  90 . 
     Fluid coming from the pump  94  flows to the directional valve  40 . The directional valve  40  includes a spring  102  and a solenoid  104 . The spring  102  biases the directional valve  40  to the right as shown in FIGS. In the biased position, the fluid coming from the pump  94  is transferred not to the advance pathway  106  but rather to the retract pathway  108 . The electronic solenoid  104 , when energized, will cause the directional valve  40  to shift allowing hydraulic fluid coming from the pump  94  to flow through the advance pathway  106  and allow fluid coming back from the retract pathway  108  to flow back to the reservoir  90  via the flow sensor  56 ,  68 . 
     The hydraulic circuit  88  provides connectors  110  and  112  to connect to connectors  114  and  116  on an external device  118 . The connectors  110 ,  112 ,  114 , and  116  include check valves. The connectors  110 ,  112 ,  114  and  116  may be quick connectors. In some embodiments in accordance with the invention the external device or tool  118  is a hydraulic wrench. The hydraulic wrench  118  includes a hydraulic cylinder  120  which contains a dual action hydraulic piston  122 . The dual action hydraulic piston  122  includes a front face  124  and a rear face  126 . When fluid flows through the advance pathway  106  the hydraulic fluid acts upon the front surface  124  of the hydraulic piston  122  causing the hydraulic system piston  122  to advance out of the hydraulic cylinder  120 . 
     When the piston  122  is moved to its extreme position out of the cylinder  120  flow through the hydraulic circuit will stop this will cause the microcontroller to de-energize the solenoid  104  associated with the directional valve  40 . The directional valve  40  will then switch the flow from the pump  94  to the retract pathway  108  this will allow fluid to flow through the connectors  112   116  into the cylinder  120  and act on the rear side  126  of the piston  122  causing the piston  122  two move into the cylinder  120 . This movement will again cause fluid to move through the circuit  88  until the piston  122  moves to the end of its stroke the piston  122 . Once inside the cylinder  120  the piston  122  will stop. When this lack of flow is sensed, the controller will energize the solenoid  104  associated with the directional valve  40  causing the directional valve  40  to move to the left to once again cause flow from the pump  94  to move through the advance pathway  106  into the cylinder  122  act upon the front face will  124  of the piston  122 . 
     If, for a set amount of time, no flow is detected in the circuit  88  by either flow sensor assemblies  58 ,  70  or  56 ,  68 , a solenoid  144  associated with a dump valve  140  may be de-energized allowing the spring  142  to move dump valve  140  to the right in  FIG. 4  allowing the system to move hydraulic fluid into the reservoir  90 . In some embodiments in accordance of the invention, the set amount time is 5 seconds. Other amounts of time and also be set by a user. If the dump valve  140  is de-energized for a set length of time, the motor  96  and pump  94  will cease operation as the controller will know that the tool  118  has stalled. In some embodiments, this set length of time is 5 seconds. An example of the tool stalling will be a hydraulic wrench fully turning a nut and unable to turn the nut further. 
     The flow of fluid through the system  88  can be monitored by the user by viewing the pressure gauge  42  which is connected by the connection  132  including check valves  134 ,  136 . Optionally, the connection  132  is a quick connect which allows a user to swap out different instruments or pressure gauges  42 . If too much pressure builds up in in retract pathway  108  a relief valve  146  will move in to an open position allowing flow to move into the reservoir  90 . A stalled tool  118  may cause such a build up of pressure. In some embodiments of the invention, a maximum permissible pressure may be 1500 PSI. Other embodiments may have different maximum pressures or may trigger the movement of the relief valve  146  at different pressures. 
     In some embodiments in accordance with the invention, a maximum amount of desired torque may be set and associated with a pressure regulator valve  128 . The pressure regulator valve  128  may have a spring  130  biasing the pressure regulator valve  128  in a certain position once a desired torque level is achieved. The pressure regulator valve  128  will move against the force of the spring  130  to an open position allowing the hydraulic circuit  88  to move fluid into the reservoir  90  flow into the reservoir  90  will be detected by the flow sensor assembly  58 ,  70  which will indicate to the controller that a desired torque is achieved. Once it is been indicated that desired torque is achieved the fluid will move through the pressure regulator valve  128  and not through the remainder of the circuit. If no flowing detected by flow sensor  56 ,  68  or flow is sensed by flow sensor  58 ,  70  for a set amount of time solenoid  144  associated with a dump valve  140  may be de-energized allowing the spring  142  to move dump valve  140  to the right in  FIG. 4  allowing the system to move hydraulic fluid into the reservoir  90 . If, for a set amount of time, neither button  30  or button  28  in  FIG. 5  are depressed the motor  96  and pump  94  will be shut down by the controller. 
       FIG. 5  is illustrates an electrical schematic diagram  148  in accordance with an embodiment of the invention. The schematic diagram  148  illustrates the motor  96  electrically connected via relays  160  to line in  150  and neutral  152  both the line in and  150  neutral lines  152  may contain fuses  156 . A ground line  154  is also used. The line in  150  and neutral  152  flow into a power source  162 . The power source  162  may be connected to an on switch  164  and an off switch  166 . An indicator light  168  may be present to illustrate that the on switch  164  is set in the on position. Contacts  170  may also be present and are shut and/or controlled by the relay  172 . The flow sensors  68  and  70  which are the proximity switches are connected to the controller  174  and input an on-off signal into the controller  174 . In other embodiments in accordance with the invention the flow sensors  60  and  70  may provide additional signals rather than a simple on-off signal. 
     The hand pendant  26  is also operatively connected to the microcontroller  174 . The hand pendant  26  may have a stop actuator  32 , an auto cycle actuator  30  and, in some embodiments, a manual actuator  28  which allows an operator to operate the auto cycle pump  10  in a traditional manual manner. The actuators  28 ,  30  and  32  connected to the microcontroller  174 . The stop actuator  32  allows an operator to stop the action of the pump  94 . The auto cycle actuator  30  allows the pump  94  to operate in the automatic cycle described herein. Outputs from the logic controller or microcontroller  174  can energize or de-energize solenoids associated with the various valves. The relay  176  is also controlled by the controller  174 . The relay  176  controls the contacts  160  and if either of the two contacts  160  are in an open position then the motor  96  will either shut down or not turn on. 
     The operation of the auto cycle pump  10  will now be described. After the operator has attached the tool  118  such as a hydraulic wrench and set it in a desired condition, the operator can depress and hold down the auto cycle button  30  on the hand pendant  26 . The logic controller  174  sends a signal to the directional valve  40  and to the dump valve  140 . These two valves  40  and  140  are energized and move to a position against their springs  102  and  142  respectively. The dump valve  140  shifts blocking flow from the reservoir  90  through the dump valve  140 . The directional valve  40  shifts directing flow from the pump  94  to the advanced pathway  106  to the tool  118 . The piston  122  within the tool  118  begins to extend. The return fluid from the tool  118  is returned through the retract pathway  108 . From the retract pathway  108  the hydraulic fluid is directed through poppet valve  56  of the flow sensing manifold  22  (see  FIG. 3 ). The poppet valve  56  moves to the left and is sensed by the proximity switch  68 . The proximity switch  68  sends a signal to the logic controller  174  that the tool  118  is moving or in other words that there is flow through the hydraulic circuit  68 . The logic controller  174  starts monitoring the time that flow occurs. When the piston  124  in the tool  118  meets the end of its stroke, hydraulic flow through the circuit  88  stops. The controller  174  de-energize the valve  40  and the poppet valve  56  moves back to the right due to the force of the spring  66 . 
     The proximity switch  68  may provide a signal to the logic controller  174  indicating that there is no flow through the hydraulic circuit  88 . In some embodiments in accordance with the invention, this signal is actually a lack of signal as the proximity switch  68  opens and stops providing a signal to the logic controller  174 . The logic controller  174  stores the time value measured from when the proximity switch  68  indicates no flow through the hydraulic circuit  88 . The logic controller  174  removes the signal to the solenoid  104  in the directional valve  40  causing the directional valve  40  to shift directing flow from the pump  94  to the retracting pathway  108  of the tool  118 . The piston  124  in the tool  118  begins to retract. The return fluid from the tool  118  is returned through the extend pathway  106  from the extending pathway  106  the fluid is directed through the poppet valve  56  of the flow sensing manifold  22 . 
     The poppet valve  56  moves to the left and is sensed by the proximity switch  68 . Proximity switch  68  sends a signal to the logic controller that the tool has moved or in other words that flow is occurring through the hydraulic circuit  88 . The logic controller  174  starts to monitor the time where flow is occurring. 
     When the piston  124  in the tool  118  meets the end of its stroke the hydraulic flow stops. The poppet valve  56  moves back to the right due the force of the spring  66  as the flow of hydraulic fluid no longer acts on the poppet valve  56 . The proximity switch  68  removes the signal from the logic controller  174  or in other words indicates to the logic controller  174  is that there is no flow through the hydraulic circuit  88 . The logic controller  174  records the time value of how much time passes where there was flow through the circuit  88 . The sequence stated above is repeated until the preset pressure is met. The logic controller updates the cycle time values for each cycle. In this way, false signals may be ignored no special settings are needed when changing from small to large tools or short to long hoses connecting the tools  118  to the auto cycle pump  10 . 
     When a preset pressure has been met, flow is directed from the pump  94  through the pressure regulator  128 . Flow is then directed from the pressure regulator  128  through a poppet valve  58  in the flow sensing manifold  22 . The poppet valve  58  moves to the right and the proximity switch  70  sends a signal to the logic controller  174 . The logic controller senses that there is a signal coming from the proximity switch  70  and checks the status of proximity switch  68  to ensure the hydraulic piston  122  in the tool  118  has stopped moving thus stopping flow through the hydraulic circuit  88 . 
     Once the logic controller  174  has determined that there has been no flow through the circuit  88  for a predetermined length of time such as for example 5 seconds, the logic controller  174  will remove the signal from the solenoid  104  in the directional valve  40 , and in the solenoid  144  in the dump valve  140  causing the directional valve  40  to move to the left. As result of the force of the spring  142  the dump valve  140  also moves to the left. Thus the directional valve  40  shifts to the retract pathway  108  and the dump valve  140  directs hydraulic fluid to the reservoir  90 . After being in this position for about 5 seconds the controller  174  will cause the motor  96  to shut off. 
     The many features and advantages of the invention are apparent from the detailed specification, and thus, it is intended by the appended claims to cover all such features and advantages of the invention which fall within the true spirit and scope of the invention. Further, since numerous modifications and variations will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation illustrated and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.