Pressure relief assembly for hydraulic pump

Abstract

The hydraulic pump includes: a housing including a working port; a bladder storing hydraulic fluid; and a pump assembly that pumps hydraulic fluid from the bladder to the working port. The bladder includes a bladder pressure relief assembly with a control element movable between a first position that seals the bladder from the atmosphere and a second position that opens the bladder to the atmosphere to release pressure within the bladder. When the pressure in the bladder reaches a set pressure, the control element moves from the first position to the second position.

Description

Technical Field

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 579,270, filed on August 28, 2023, the entire contents of which are incorporated herein by reference. Background Art

[0002] The present disclosure relates to hydraulic pumps and systems, and more particularly to systems and methods for single-acting cordless hydraulic pumps for use with hydraulic tools. Hydraulic tools can be used to provide a mechanical advantage to an operator performing work on a workpiece. For example, the hydraulic tool can be a cutting device having a blade for cutting an object into separate parts. For another example, the hydraulic tool can be a crimping device for crimping connections, thereby connecting two separate parts together by deforming one or both workpieces and holding them together. For another example, the hydraulic tool can be a lifting cylinder for lifting a workpiece and / or a pipe bender for bending a workpiece.

[0003] Generally speaking, a hydraulic tool is connected to a hydraulic pump, which is operable to pressurize a hydraulic fluid. The hydraulic pump delivers the pressurized hydraulic fluid to a cylinder in the hydraulic tool, and the hydraulic tool uses the pressurized hydraulic fluid from the hydraulic pump to perform work, such as crimping, cutting, lifting, etc. Therefore, the hydraulic pump needs to have a mechanism for pressurizing, maintaining, and releasing the hydraulic fluid. Summary of the invention

[0004] According to one aspect of the present disclosure, a hydraulic pump may include: a housing including a working port; a bladder storing hydraulic fluid; and a pump assembly that pumps the hydraulic fluid from the bladder to the working port via an outlet line. The bladder may include a bladder pressure relief assembly coupled to the bladder. The bladder pressure relief assembly may include a control element that is movable between a first position that seals the bladder relative to the atmosphere and a second position that opens the bladder to the atmosphere to release pressure within the bladder. When the pressure in the bladder reaches a set pressure, the control element may move from the first position to the second position.

[0005] In some examples, the hydraulic pump may further include a drain valve positioned between the workport and the bladder to control fluid flow between the workport and the bladder.

[0006] In some examples, the dump valve may include a knob that extends outside the housing to allow a user to operate the dump valve.

[0007] In some examples, the set pressure of the bladder pressure relief assembly may be adjustable.

[0008] In some examples, the bladder may also include a removable fill cap.

[0009] In some examples, a bladder pressure relief assembly may be coupled to the filler cap.

[0010] In some examples, the filler cap may extend outside the housing.

[0011] In some examples, the filler cap may include a head and a handle coupled to the capsule. A control element may be movably disposed in a channel extending between the head and the handle.

[0012] In some examples, the head can include a first channel. The handle can include a second channel selectively fluidly coupled by a control element.

[0013] In some examples, the first channel can extend toward the handle and radially outward from the head.

[0014] In some examples, the head may define a flange, and the distal end of the first channel is located along a side of the flange that faces the capsule.

[0015] In some examples, the housing may include a battery receptacle configured to couple a battery to provide power to the hydraulic pump.

[0016] In some examples, the hydraulic pump may further include a workport coupled to a manifold disposed within the housing to allow fluid to flow between the bladder and the workport. The workport may be configured to be coupled to an end effector that performs a work operation.

[0017] According to another aspect of the present disclosure, a bladder assembly for a hydraulic tool may include: a reservoir defining an inner cavity, the inner cavity configured to receive a hydraulic fluid; and a filler cap removably coupled to the reservoir. The filler cap may define a channel and may include a control element movably disposed along the channel. The control element may be movable between a first position that seals the inner cavity relative to the atmosphere and a second position that vents the inner cavity to the atmosphere to release pressure within the bladder. When the pressure in the bladder reaches a set pressure, the control element may be movable from the first position to the second position.

[0018] In some examples, the set pressure may be an adjustable set pressure.

[0019] In some examples, the filler cap may include a handle coupled to the reservoir and a head extending from the handle for user manipulation. The head may include a first section of the channel extending toward a periphery of the head and toward the reservoir.

[0020] According to another aspect of the present disclosure, a power tool may include: a housing including a battery; a drive unit disposed within the housing; a pump operably coupled to the drive unit to provide a pressurized fluid; a trigger allowing a user to control the drive unit to operate the power tool; and a bladder assembly disposed in the housing. The bladder assembly may include: a reservoir defining an inner cavity configured to receive a hydraulic fluid; and a filler cap removably coupled to the reservoir. The filler cap may define a channel and may include a control element movably disposed along the channel. The control element is movable between a first position and a second position, the first position sealing the inner cavity relative to the atmosphere, the second position venting the inner cavity to the atmosphere so as to release the pressure within the bladder when the pressure in the bladder reaches a set pressure.

[0021] In some examples, the filler cap may extend outside the housing to allow a user to change the set pressure.

[0022] A power tool may include a manifold having work ports coupled to an end effector that performs a work operation.

[0023] In some examples, the bladder may include a mounting bracket coupled between the reservoir and the filler cap.The mounting bracket may be coupleable to the housing.

[0024] The features, functions, and advantages can be achieved independently in various embodiments of the present disclosure, or they may be combined in yet other embodiments in which further details can be seen with reference to the following description and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings, which are included in and constitute a part of this specification document, schematically illustrate embodiments of the present invention and, together with the description, are used to explain the principles of the embodiments of the present invention:

[0026] Figure 1 is a front isometric view of a hydraulic pump according to an embodiment of the present disclosure;

[0027] Figure 2 yes Figure 1 A rear axonometric view of the hydraulic pump;

[0028] Figure 3 is a schematic diagram of a hydraulic power tool system, which includes Figure 1 Hydraulic pump;

[0029] Figure 4 yes Figure 1 A partial cross-sectional view of a pump, manifold and bladder assembly of a hydraulic pump;

[0030] Figure 5 yes Figure 1A detail view of the indicator of the hydraulic pump taken from line IV-IV;

[0031] Figure 6 yes Figure 1 An axonometric view of a bladder pressure relief assembly of a hydraulic pump;

[0032] Figure 7 yes Figure 6 Another axonal mapping of the sac pressure relief component;

[0033] Figure 8 yes Figure 6 A cross-sectional view of the bladder pressure relief assembly taken along line VIII-VIII;

[0034] Fig. 9 yes Figure 8 An axonometric cross-sectional view of a bladder pressure relief assembly;

[0035] Fig.10 yes Figure 6 An axonometric view of a filling cap of a bladder pressure relief assembly;

[0036] Fig.11 yes Fig. 9 A cross-sectional view of the filling cap taken along line XI-XI;

[0037] Fig.12 is a schematic diagram of a hydraulic power tool system, the system comprising Figure 1 Hydraulic pump;

[0038] Fig.13 yes Fig.12 A flow chart of an open loop motor speed control method for a hydraulic power tool system; and

[0039] Fig.14 yes Fig.12 Flow chart of a closed-loop motor speed control method for a hydraulic power tool system. DETAILED DESCRIPTION

[0040] The concepts disclosed in the discussion herein are described and illustrated with reference to exemplary devices. However, these concepts are not limited to their construction details and the arrangement of the components in the illustrative embodiments, and can be practiced or implemented in a variety of other ways. The terms herein are used for descriptive purposes only and should not be considered restrictive. Words such as "including," "comprising," and "having," and variations thereof as used herein are intended to cover the items listed thereafter, equivalents, and additional items.

[0041] Unless otherwise specified or limited, the terms "about" and "approximately" with respect to a reference value herein refer to a variation of ±20% or less (e.g., ±15, ±10%, ±5%, etc.) relative to the reference value, and include the endpoints of the range. Similarly, as used herein with respect to a reference value, the term "substantially equal" (and similar terms) refers to a variation of ±5% or less (e.g., ±2%, ±1%, ±0.5%) relative to the reference value. Where specifically specified, "significantly" may refer to a variation in a numerical direction relative to the reference value. In particular, the term "significantly less than" a reference value (and similar expressions) refers to a decrease of 30% or more (e.g., 35%, 40%, 50%, 65%, 80%) relative to the reference value, and the term "significantly greater than" a reference value (and similar expressions) refers to an increase of 30% or more (e.g., 35%, 40%, 50%, 65%, 80%) relative to the reference value.

[0042] Generally speaking, hydraulic pumps can be used to convert mechanical power into hydraulic energy. As described above, hydraulic pumps can be used in various environments, such as powering tools or loading hydraulic systems. The pump can be integrated into a power tool, or it can be configured as a stand-alone pump that can be connected to different types of end effectors to perform various work operations. Therefore, the hydraulic pumps disclosed herein can be embodied in many different forms. Several specific embodiments are discussed herein, and it can be understood that the embodiments described in this disclosure are merely to be regarded as embodiments of the principles described herein, and the disclosed technology is not intended to be limited to the examples shown.

[0043] In general, some embodiments provide a single-acting, battery-powered hydraulic pump for use with a hydraulic tool. "Single-acting" generally refers to a type of pump that moves fluid only during one stroke of a piston or plunger; however, other types of pumps (e.g., double-acting pumps) may be used. In some embodiments, the hydraulic pump may include a variable speed motor and a pump controller that is configured to control the variable speed motor using open loop control based on a percentage of motor power applied or using closed loop control based on actual motor speed. In addition, the hydraulic pump may include a manifold with an overpressure protection system that includes dual chambers with corresponding pressure relief valves and a check valve located therebetween. The overpressure protection system can release pressurized fluid to the atmosphere to prevent pump overpressure conditions as well as external load overpressure conditions.

[0044] For example, an overpressure protection system can include a bladder pressure relief assembly. The bladder pressure relief assembly can be used to protect a hydraulic pump or system from over-pressurization. The bladder pressure relief assembly can be advantageously integrated into a filler cap for a hydraulic pump. By integrating the bladder pressure relief assembly into the filler cap, the number of ports between the hydraulic tank or reservoir and the atmosphere can be reduced compared to conventional pressure relief valves and ports. Typically, the bladder pressure relief assembly can be opened when the pressure in the bladder of the hydraulic pump exceeds a set pressure. When there is too much liquid in the bladder, the bladder pressure relief assembly can allow air and fluid to be discharged to the atmosphere (e.g., outside the pump).

[0045] Reference now Figure 1 and Figure 2 , a hydraulic pump 100 is shown. The hydraulic pump 100 may be configured as a single-acting hydraulic pump; however, other configurations may also be used. According to some embodiments of the present disclosure, the hydraulic pump 100 may be part of a hydraulic power tool system 200. Figure 1 and Figure 2 As shown, the hydraulic pump 100 may include a housing 104, a working port 106, a cover 152, a first indicator 153, a second indicator 154, a handle 110, a trigger 112, a lock 114, and a battery receptacle 115 including a battery terminal 116 configured to be coupled to one or more batteries. Figure 2 As shown, the hydraulic pump 100 (eg, the bladder thereof) may further include a filler cap 118. In other words, the bladder 122 includes the filler cap 118 and the reservoir 117 (see Figure 4 ), the reservoir defines an inner cavity 119 for holding fluid for the hydraulic pump 100 (see Figure 4 ). In some cases, the reservoir can be a flexible bag, or the reservoir can also be a rigid container. The bladder can include a mounting bracket 121 coupled to the housing 104, the mounting bracket further being located between the reservoir 117 and the refill cap 118. In the illustrated embodiment, the refill cap 118 can be coupled to the opening 120 of the bladder 122 (see Figure 7 ). For example, the filler cap 118 can be threadedly coupled to the opening 120 of the bladder 122, but other fixing methods are also possible, such as snap-on, press-fit. In addition, in the illustrated embodiment, the filler cap 118 can include a bladder pressure relief assembly 123, as will be described in further detail below.

[0046] Figure 3 A hydraulic power tool system 200 is shown, including a hydraulic pump 100 and a hydraulic tool 300 (e.g., an end effector configured to perform a certain type of work operation, such as crimping, cutting, drilling, punching, lifting, spreading, etc.). Generally, the hydraulic pump 100 can be operated to provide a pressurized fluid (e.g., hydraulic oil) to actuate the hydraulic tool 300. For example, Figure 3As shown, the hydraulic pump 100 may include a power unit 124, a pump assembly 126, a manifold 128, a bladder 122, a user interface 130, a controller 132 with a processor 134 and a memory 135, a work port 106, and a power source or battery 136. The hydraulic pump 100 may be removably coupled to a hydraulic tool 300 via a fluid supply line 138 (e.g., a pipe) extending from the work port 106. In addition, the hydraulic tool 300 may include a tool head 140, a hydraulic cylinder 142, and a return spring 144.

[0047] In operation, the power unit 124 can be powered by the battery 136 to drive the pump assembly 126. The power unit 124 can be controlled by the controller 132 in response to user input from the user interface 130 (e.g., in response to the pressing of the trigger 112). The pump assembly 126 pumps pressurized fluid from the bladder 122 through the manifold 128 connected between the pump assembly 126 and the bladder 122, and through the fluid supply line 138 to the hydraulic tool 300 via the work port 106. Within the hydraulic tool 300, the pressurized fluid pushes the hydraulic cylinder 142, which actuates the tool head 140. For example, the hydraulic tool 300 (e.g., the tool head 140) can include an end effector 141 (e.g., a set of chucks) for performing a work function, and the hydraulic cylinder 142 includes a piston 145 that can move one or two chucks closer to each other to cause a crimping or cutting operation. In another example, the end effector 141 can be a movable lifting structure, and the hydraulic cylinder 142 can move the lifting structure to change the height of the workpiece supported by the movable lifting structure. Other examples are possible, such as but not limited to a tool head 140 having a movable element (e.g., a bending die and / or a bending roller) that can move the workpiece relative to a stationary element (e.g., a fixed die and / or a fixed roller) to change the shape of the workpiece.

[0048] Once the operation is completed, the return spring 144 can force the fluid from the hydraulic tool 300 through the fluid supply line 138 and back into the hydraulic pump 100, more specifically, back into the bladder 122. In this way, the hydraulic pump 100 is a single-acting pump. The hydraulic pump 100 includes a workport 106 and forces the fluid in one direction, and the hydraulic tool 300 includes a spring or gravity or other external force to return the fluid to the hydraulic pump 100. As a result, the external force, rather than the hydraulic tool 300 or the user, releases the pressure within the hydraulic tool 300 to force the fluid back into the hydraulic pump 100.

[0049] Figure 4 The interior view of FIG. 1 shows the power unit 124, the pump assembly 126, the manifold 128, the bladder 122, and the cover 152. Figure 4As shown, the power unit 124 may include a motor 146 configured to convert electrical energy into rotational motion to operate the pump assembly 126. In addition, in some embodiments, the power unit 124 may include a motor 146 with a transmission 127. In the embodiment shown, the transmission 127 includes a planetary gear set, but the transmission 127 may be a manual transmission, an automatic transmission, a hydraulic transmission, or a gearbox torque converter, or other transmission types. In some embodiments, the motor 146 may be a variable speed motor. In some embodiments, the motor 146 may be a brushless DC motor.

[0050] The power unit 124 may be powered by a power source (e.g., a battery 136), such as Figure 3 As shown. Thus, the hydraulic pump 100 can be considered a cordless pump because it is battery powered. In some embodiments, the battery 136 can be an 18 volt battery, a 12 volt battery, a 20 volt battery, or other voltage battery. The battery 136 can be a lithium ion battery, a nickel cadmium battery, or other types of battery chemistries. Furthermore, in some embodiments, the battery 136 can be removable from the hydraulic pump 100. For example, Figure 1 and Figure 2 As shown, the hydraulic pump 100 may include a battery terminal 116 to which a battery 136 may be removably coupled. Thus, the battery 136 may be removed from the hydraulic pump 100 and recharged and / or replaced when necessary.

[0051] In addition, the power unit 124 can be controlled by a controller 132. Therefore, the controller 132 can communicate with the motor 146. The controller 132 can be implemented using hardware, software, and / or firmware. For example, Figure 3 As shown, the controller 132 may include one or more processors 134 and a memory 135 (eg, a non-transitory computer readable memory) storing machine language instructions or other executable instructions. When the instructions are executed by the one or more processors 134, the instructions may cause the controller 132 to perform various operations of the hydraulic pump 100.

[0052] For example, the memory 135 may include instructions that, when executed by the processor(s) 134, cause the controller 132 to operate the motor 146 in response to a user input from an operator. Such a user input may be the operator pressing the trigger 112. Figure 1 and Figure 2As shown, the trigger 112 can be positioned along the handle 110 of the housing 104, thereby allowing an operator to grasp the handle 110 and actuate the trigger 112. However, in other embodiments, the trigger 112 can be located at other locations along the housing 104.

[0053] In some embodiments, the trigger 112 can act as an on-off switch, such that when the trigger 112 is pressed, the controller 132 turns on and operates the motor 146 to operate the pump assembly 126, and the controller turns off the motor 146 when the trigger 112 is released. In other embodiments, as further described below, the trigger 112 can be a variable trigger, such that the controller 132 controls the speed of the motor 146 in a relationship that is directly related to the amount of force applied to the trigger 112, or controls the speed of the motor 146 in a relationship that is directly related to the amount of travel of the trigger 112 (i.e., from an unpressed state to a fully pressed state). In other examples, the trigger 112 can be another type of trigger, such as an on-off switch, a stepped trigger, etc. In such an embodiment, when the trigger 112 is no longer pressed, the controller 132 still turns off the motor 146. In addition, in some embodiments, the hydraulic pump 100 can include additional user inputs to prevent the motor from operating. For example, if Figure 1 and Figure 2 As shown, the hydraulic pump 100 may include a lock 114 (e.g., on the handle 110) to prevent accidental pulling of the trigger. In some embodiments, the lock 114 may be a mechanical lock that prevents the trigger 112 from being pressed. In other embodiments, the lock 114 may be an electronic lock that, when actuated, sends a signal to the controller 132 to prevent the motor from running.

[0054] With further reference to the pump assembly 126, as Figure 3 and Figure 4 As shown, the pump assembly 126 may include a pump 148 coupled to the power unit 124. In some embodiments, the pump 148 may be a radial pump including a piston 145 and a cam 155 driven by the motor 146. For example, Figure 4 As shown, the pump 148 may include a shaft 149 operably coupled to the motor 146. A cam 155 is coupled to the shaft 149 and rotates with the shaft 149. The cam 155 acts on the piston 145 to convert the rotary motion of the motor 146 into reciprocating linear motion of the piston 145. The reciprocating linear motion of the piston 145 draws fluid from the bladder 122 and supplies pressurized fluid to the workport 106 through the manifold 128 and to the hydraulic tool 300 through the fluid supply line 138. It will be appreciated that a valve or other fluid control mechanism may be provided to prevent backflow from the piston 145.

[0055] Figure 5 and Figure 61 shows an isometric view of a bladder 122 assembly that includes a bladder pressure relief assembly 123 of a hydraulic pump 100. Figure 4 As shown, the bladder 122 operates as a reservoir (e.g., a tank) for storing hydraulic fluid (e.g., hydraulic oil). In some embodiments, the bladder 122 may include an opening 120 covered by a fill cap 118. The opening 120 may serve as a fill port, and the fill cap 118 may be removed to allow the hydraulic fluid to be removed and / or refilled from the bladder 122 via the opening 120. Additionally, in some embodiments, the fill cap 118 or another portion of the housing 104 may include a transparent window 151 to allow an operator to view the interior of the bladder 122. Thus, the operator may quickly check the level of the hydraulic fluid within the bladder 122 without having to remove the fill cap 118.

[0056] As described above, the bladder 122 may also include a bladder pressure relief assembly 123. In the illustrated embodiment, the bladder pressure relief assembly 123 may be integrated into the filler cap 118. Generally, the bladder pressure relief assembly 123 may be configured as part of the overpressure protection system 147. The bladder pressure relief assembly 123 may include a pressure relief valve 150 disposed within the filler cap 118. The pressure relief valve 150 may define a set pressure at which a pressure relief condition occurs through the pressure relief valve 150. In some embodiments, the pressure relief valve 150 may also define other pressure thresholds, such as a crack pressure at which the pressure relief valve 150 first opens, the crack pressure being less than the set pressure. For example, the crack pressure may ensure that the pressure relief valve 150 is activated and opened before the pressure in the bladder 122 reaches the set pressure. Generally, the bladder pressure relief assembly 123 may protect the hydraulic pump 100, a tool (e.g., the hydraulic tool 300), and the bladder 122. That is, when the pressure in the bladder 122 exceeds a set pressure (e.g., between about 8,000 PSI and about 12,000 PSI, or between about 10,000 PSI and about 10,500 or about 10,152 PSI), the pressure relief valve 150 opens, thereby allowing fluid to be discharged to the atmosphere. In some examples, depending on the pressure output of the hydraulic pump 100 required by the user for various operations, the user can select the cracking pressure or set pressure at which the pressure relief valve 150 can open, which can provide overpressure protection for the hydraulic pump 100 and the hydraulic tool 300 at different pressures. The same pressure relief also occurs when too much fluid enters the bladder 122.

[0057] The bladder 122 can store hydraulic fluid at a low pressure level, such as atmospheric pressure or slightly above atmospheric pressure (e.g., about 30 psi to about 70 psi in some embodiments). As described above, the pump assembly 126 draws fluid from the bladder 122 and forces the pressurized fluid through the fluid supply line 138 and into the hydraulic tool 300 to perform a work operation. In addition, as Figure 3 and Figure 4As shown, fluid travels between the pump assembly 126 , the bladder 122 , and the workport 106 through the manifold 128 .

[0058] Generally, the manifold 128 can provide fluid control, set operating pressure, and / or provide overpressure relief. For example, a drain valve 108 (e.g., a manual drain valve) accessible to an operator from outside the housing 104 can be manipulated by a user to establish fluid pressure or throttle return flow. More specifically, as Figure 4 As shown, the drain valve 108 may include a cover 152 (eg, configured as a knob) extending from the housing 104 that can be moved by an operator. Fig.12 As shown, the dump valve 108 can be in communication with the third manifold line 176 between the bladder 122 and the working port 106. The first indicator 153 ( Figure 5 ) and a second indicator 154 ( Figure 5 ) can visually indicate to the user whether the dump valve 108 is in a blocked position to prevent fluid communication between the third manifold line 176 and the bladder 122 (as indicated by the first indicator 153), or whether the dump valve 108 is in an open position to allow fluid communication between the third manifold line 176 and the bladder 122 (as indicated by the second indicator 154). For example, when an operator rotates the cap 152 in a first rotational direction (e.g., clockwise) to a first (e.g., "closed") position (e.g., visible to the operator via the first indicator 153), the dump valve 108 is moved to block the third manifold line 176, thereby preventing fluid from traveling from the workport 106 back to the bladder 122. This closure, in turn, allows the pump 148 to deliver pressurized fluid through the workport 106 and maintain pressure. When the operator rotates the cap 152 in a second rotational direction (e.g., counterclockwise) to a second, “open” position (e.g., visible to the operator via the second indicator 154), the drain valve 108 moves to open the third manifold line 176, thereby opening the connection between the workport 106 and the bladder 122, thereby allowing fluid to travel from the workport 106 back to the bladder 122. As a result, pressure is released from the bladder 122, and fluid returns from the hydraulic tool 300 to the bladder 122 via the third manifold line 176 (e.g., due to a spring or other external force within the hydraulic tool 300 forcing the fluid to leave the hydraulic tool 300).

[0059] Figure 8A cross-sectional view of a bladder 122 and a bladder pressure relief assembly 123 with a filler cap 118 is shown. As shown, a pressure relief valve 150 can be integrated directly into the filler cap 118. The pressure relief valve 150 can include a control element 158 ​​configured as a valve poppet. Generally, the control element 158 ​​can sense the fluid pressure within the bladder 122. When the pressure within the bladder 122 exceeds the set pressure of the pressure relief valve 150, the control element 158 ​​can move (e.g., dislocate) and pass through an opening 162 (see FIG. 16A ) in the filler cap 118. Figure 8 ) (e.g., the first channel) discharges fluid.

[0060] Fig. 9 and Fig.10 A filler cap 118 is shown in accordance with an embodiment of the present disclosure. The filler cap 118 may include a filler cap body 240 having a head 242 and a handle 244. The head 242 may define a flange 243 and a gripping portion 245. The handle 244 may include threads configured to be received by internal threads of the opening 120 of the capsule 122. As described above, the filler cap 118, and more specifically the handle 244, may be secured to the opening 120 of the capsule 122 by other means, such as a snap-fit ​​connection or a press-fit connection, although other configurations are possible. The head 242 of the filler cap 118 may include a collar 246 and a hub 248. The collar 246 and the hub 248 may generally be substantially concentric and radially spaced apart such that one or more recesses 250 are formed therebetween. The recess 250 and other geometric features of the filler cap 118 may advantageously assist a user in grasping and securing (eg, coupling) the filler cap 118 to the bladder 122 , or removing (eg, decoupling) the filler cap 118 from the bladder 122 .

[0061] like Fig.10 As shown, handle 244 can define a passage 252 (e.g., a second passage) extending therein. When filler cap 118 is secured to bladder 122, passage 252 can be in fluid communication with control element 158 ​​and bladder 122. When control element 158 ​​is in the venting position, passage 252 can also be in fluid communication with opening 162 in filler cap 118, such that passage 252 and opening 162 define a passage through filler cap 118 between the interior of bladder 122 and the atmosphere. Fig.10 As shown, the opening 162 can extend from the interior of the filler cap 118 through each of the walls of the collar 246 and the hub 248 of the head 242. In other words, the opening 162 extends through the head 242 so that the distal end of the opening 162 is located along a side (e.g., a lower side) of the flange 243 that faces the bladder 122 or the housing 104 (e.g., located away from the user). Therefore, during a pressure relief condition, fluid can be released from the interior of the bladder 122 to the atmosphere via the control element 158 ​​through the passage 252 and the opening 162.

[0062] In use, the control element 158 ​​is in a normally closed position (eg, in a seated position) such that fluid communication between the passage 252 and the opening 162 is blocked. Fig.11 As shown, the control element 158 ​​can be biased to a closed position by the biasing element 156. As the pressure in the bladder 122 increases, the control element 158 ​​remains in the closed position until the set pressure of the pressure relief valve 150 is reached. During a pressure relief condition, the control element 158 ​​moves toward the hub 248 (e.g., away from the handle 244) to an open position (e.g., in an unseated position). When the pressure relief valve 150 is opened, excess fluid is discharged to the atmosphere through the opening 162 in the filler cap 118, thereby reducing the pressure in the bladder 122 to an amount below the set pressure. This, in turn, can protect the bladder 122 and the hydraulic tool 300 from over-pressurization. Figures 8 to 10 As shown, the position of the filler cap 118 is independent of the pressure over-protection capability of the pressure relief valve 150. That is, the opening 162 can be in various rotational positions relative to the opening 120 of the bladder 122 without affecting the pressure relief capability of the bladder pressure relief assembly 123. In the illustrated embodiment, the hub defines an inclined direction from the hub 248 toward the end of the filler cap body 240 near the handle 244 (e.g., toward the handle 244 and radially outward). This advantageously ensures that when excess fluid exits through the opening 162 in a pressure relief condition, the fluid can be directed away from the hub 248 and toward a direction away from the user. In some embodiments, it may be advantageous to have the opening 162 pointed in a strategic direction (e.g., away from a tool, a manifold, or a user).

[0063] As discussed above and as Figure 4 As shown, now refer to Fig.12 , shows a schematic diagram of the hydraulic pump 100. As discussed above, the hydraulic pump 100 may include a manifold 128. In some embodiments, in addition to the pressure relief valve 150 in the filler cap 118, the manifold 128 may also include a pressure relief valve and a check valve arrangement to provide overpressure protection for the hydraulic pump 100. Fig.12 Fluid connections are shown between the bladder 122, the pump assembly 126, the manifold 128, and the hydraulic tool 300. For example, the hydraulic pump 100 includes: a pump inlet line 168 located between the bladder 122 and the pump assembly 126; an outlet line 170 located between the pump assembly 126 and the workport 106 and extending through the manifold 128; a first manifold line 172 located between the bladder 122 and the outlet line 170; a second manifold line 174 located between the bladder 122 and the outlet line 170; and a third manifold line 176 located between the bladder 122 and the outlet line 170.

[0064] Still refer to Fig.12As described above, the bladder 122 can store hydraulic fluid at atmospheric pressure or near atmospheric pressure. In some embodiments, the bladder 122 can include a bladder pressure relief assembly 123 to maintain the pressure within the bladder 122 at or below the pressure threshold. In addition, within the pump assembly 126, the first check valve 180 ( Fig.12 ) is located along the pump inlet line 168 between the pump 148 and the bladder 122, a second check valve 182 ( Fig.12 ) is located along the outlet line 170 between the pump 148 and the third check valve 192. The first and second check valves 180, 182 can allow fluid movement from the bladder 122 through the pump 148 and prevent fluid from flowing back from the pump 148 to the bladder 122, thereby enabling the pump 148 to operate properly to provide pressurized fluid through the outlet line 170.

[0065] Still refer to Fig.12 , the manifold 128 may include at least a portion of the outlet line 170. Within the manifold 128, the hydraulic pump 100 may include a first chamber 184 ( Figure 4 )、first pressure relief valve 186、second chamber 188( Figure 4 ), a second pressure relief valve 190, a check valve 192, and a drain valve 108. Via the outlet line 170, the first chamber 184 can be connected to the pump assembly 126, the second chamber 188 can be connected to the first chamber 184, and the work port 106 can be connected to the second chamber 188 (the work port can be further connected to the hydraulic tool 300). The check valve 192 can be positioned between the first chamber 184 and the second chamber 188 along the outlet line 170 to allow fluid to flow from the first chamber 184 to the second chamber 188 and prevent fluid from flowing from the second chamber 188 to the first chamber 184.

[0066] The first pressure relief valve 186 can be connected to the first chamber 184 so that when the first chamber 184 reaches the first pressure, the first pressure relief valve 186 opens to allow fluid to flow from the outlet line 170 back to the bladder 122 via the first manifold line 172. Therefore, the pressure in the outlet line 170 drops when the first pressure is reached, which can protect the pump assembly 126 from excessive pressure within the hydraulic pump 100. Therefore, the first chamber 184 and the first pressure relief valve 186 can function as a primary pump overpressure protection mechanism.

[0067] In addition, the second pressure relief valve 190 can be connected to the second chamber 188 so that when the second chamber 188 reaches the second pressure, the second pressure relief valve 190 opens to allow fluid to flow from the outlet line 170 back to the bladder 122 via the second manifold line 174. Therefore, the pressure in the outlet line 170 drops when the second pressure is reached, which can protect the hydraulic pump 100 from overpressure from an external load (e.g., from the hydraulic tool 300). In addition, the second chamber 188 and the second pressure relief valve 190 can be used as a secondary pump overpressure protection mechanism. For example, in some embodiments, the first pressure relief valve 186 can be set at a lower pressure than the second pressure relief valve 190. Therefore, if the first pressure relief valve 186 fails, the second pressure relief valve 190 can still release the overpressure of the pump. In one embodiment, the first pressure is about 10250 psi and the second pressure is about 11500 psi. In such an embodiment, the hydraulic pump 100 can be considered to be rated at 10000 psi.

[0068] As described above, in some embodiments, the controller 132 can operate the motor 146 at a variable speed, such as relative to the operator force applied to the trigger 112 or the amount of travel of the trigger 112. For example, Fig.11 and 12 A method of variable motor speed control according to some embodiments is shown. In some embodiments, Fig.11 and Fig.12 The method may be performed by the controller 132 (eg, the method may be stored in a memory for execution by a processor of the controller 132). It should be noted that although some steps are Fig.11 and Fig.12 Although shown in the drawings and described below in a particular order, in some embodiments, these steps may be performed simultaneously with other steps, or in an order different from that shown and described, or more or fewer steps may be performed.

[0069] For example, Fig.13 A method 202 for open loop control is described. In general, Fig.13The method 202 is performed by changing the power of the motor 146. More specifically, at step 204, the battery 136 is connected to the hydraulic pump 100 to provide power for the hydraulic pump 100. At step 206, the controller 132 determines whether the pressure in the bladder 122 has exceeded the set pressure. If the bladder pressure exceeds the set pressure, the pressure relief valve 150 opens at step 207 and returns to step 204. If the pressure in the bladder 122 does not exceed the set pressure, the controller 132 continues to step 208 and determines whether any overload is occurring (e.g., an operating parameter of the system exceeds a predetermined range or threshold). For example, an overload can be detected when the motor 146 draws a current exceeding a threshold. As another example, an overload can be detected when the temperature of the motor 146 exceeds a threshold.

[0070] If an overload is detected, as determined in step 208, the controller 132 determines at step 210 whether the motor 146 is running. If so, the controller 132 stops the motor 146 at step 212. If not or after the controller 132 stops the motor 146 at step 212, the controller 132 repowers the hydraulic pump 100 at step 214. For example, the controller 132 may repower by disconnecting the electrical connection between the battery 136 and the motor 146 and then restoring the electrical connection between the battery 136 and the motor 146. After repowering at step 214, the controller 132 returns to step 204.

[0071] Returning to step 208, if an overload is not detected, the controller 132 determines at step 216 whether the trigger 112 is depressed to greater than about 10% of its total travel (e.g., "total travel" is in a fully depressed state). If not, the controller 132 determines at step 218 whether the motor 146 is running. If the motor is running, the controller 132 stops the motor 146 at step 220. If the motor is not running or after the controller 132 stops the motor 146 at step 220, the controller 132 returns to step 204.

[0072] Returning to step 216, if the trigger 112 is depressed to greater than about 10% of its total travel, the controller 132 operates the motor 146 at a percentage of motor power that correlates to the percentage of travel of the trigger 112 in step 222. For example, if the travel of the trigger 112 is 50%, the controller 132 may operate the motor 146 at 50% of the power of the motor 146. As another example, if the travel of the trigger 112 is 100% (i.e., the trigger 112 is fully depressed), the controller 132 may operate the motor 146 at 100% of the power. Additionally, the controller 132 loops back to step 208 to continue checking for overload while operating the motor 146.

[0073] Fig.14 A closed loop variable speed motor control method 260 is shown. In general, Fig.14 The closed-loop method controls the actual motor speed (eg, in revolutions per minute (RPM)). Fig.14 A closed-loop approach to starting out could include Fig.13 146 , and therefore, the same steps are numbered accordingly. However, after step 216, if the trigger 112 is pressed to more than 10% of its total travel, the controller 132 operates the motor 146 at a percentage of motor power that correlates to the percentage of travel of the trigger 112 to obtain the desired speed at step 222. The controller 132 then determines at step 224 whether the speed error is zero. That is, the controller 132 determines whether the actual pump speed (e.g., motor speed) is equal to the desired pump speed. If so, the controller 132 loops back to step 208 to continue to check for overload while operating the motor 146. If, at step 224, the speed error is not equal to zero, the controller 132 uses a proportional-integral-derivative control mechanism at step 226 to update the duty cycle of the motor 146 to try to match the actual motor speed to the desired motor 146 speed. The controller 132 then loops back to step 208 to continue to check for overload while operating the motor 146.

[0074] The motor 146 (or more generally, the power unit 124) can be operated according to the methods described herein or other methods not specifically described herein to actuate the pump assembly 126 to provide pressurized fluid to the hydraulic tool 300. For example, the motor 146 can actuate the pump assembly 126 to pump fluid to the hydraulic tool 300 at increasing fluid pressure until a maximum operating pressure is reached. The rate at which the fluid pressure increases toward the maximum operating pressure can be related to the speed at which the motor 146 is controlled and the external load from the hydraulic tool 300. Therefore, by being able to vary the speed of the motor 146 as described above, the pump speed (e.g., motor speed) can also be controlled.

[0075] In view of the above, some embodiments provide a battery powered hydraulic pump for use with a hydraulic tool. The hydraulic pump may include a variable speed motor that is controlled by an open loop mechanism in which the motor power percentage is controlled, or by a closed loop mechanism in which the actual pump speed is controlled by a proportional integral derivative (PID) control mechanism. In addition, the hydraulic pump may include a manifold with primary and secondary overpressure protection that can relieve overpressure in the hydraulic pump due to pump overpressure or external overpressure.

[0076] The description of different advantageous embodiments is for the purpose of illustration and description, and the description is not intended to be exhaustive or limited to the embodiments in the disclosed form. Many modifications and variations will be apparent to those of ordinary skill in the art. Further, different advantageous embodiments may provide different advantages over other advantageous embodiments. The selected one or more embodiments are chosen and described in order to best explain the principles of the embodiments, the practical application, and to enable others of ordinary skill in the art to understand the disclosure of various embodiments with various modifications suitable for the particular use contemplated.

Claims

1. A hydraulic pump, comprising: a housing including a working port; a bladder for storing hydraulic fluid; a pump assembly that pumps hydraulic fluid from the bladder to the workport; and A bladder pressure relief assembly is connected to the bladder, the bladder pressure relief assembly includes a control element, the control element is movable between a first position and a second position, the first position seals the bladder relative to the atmosphere, the second position opens the bladder to the atmosphere to release the pressure in the bladder, and when the pressure in the bladder reaches a set pressure, the control element moves from the first position to the second position. 2 . The hydraulic pump of claim 1 , further comprising a drain valve positioned between the workport and the bladder to control fluid flow between the workport and the bladder.

3. The hydraulic pump according to claim 2, wherein: The relief valve includes a knob extending outside the housing to allow a user to manipulate the relief valve.

4. The hydraulic pump according to claim 1, wherein: The set pressure of the bladder pressure relief assembly is adjustable.

5. The hydraulic pump according to claim 1, wherein: The bladder also includes a removable fill cap.

6. The hydraulic pump according to claim 5, wherein: The bladder pressure relief assembly is coupled to the filler cap.

7. The hydraulic pump according to claim 6, wherein: The filler cap extends outside the housing.

8. The hydraulic pump according to claim 6, wherein: The filler cap includes a head and a handle coupled to the capsule, and the control element is movably disposed in a channel extending between the head and the handle.

9. The hydraulic pump according to claim 8, wherein: The head includes a first passage and the handle includes a second passage selectively fluidly coupled by the control element.

10. The hydraulic pump according to claim 9, wherein: The first passage extends toward the handle and radially outward from the head.

11. The hydraulic pump according to claim 10, wherein: The head defines a flange, and a distal end of the first channel is located on a side of the flange facing the balloon.

12. The hydraulic pump according to claim 1, wherein: The housing includes a battery receptacle configured to be coupled to a battery to provide power to the hydraulic pump.

13. The hydraulic pump of claim 1, further comprising a workport coupled to a manifold disposed within the housing to allow fluid to flow between the bladder and the workport, the workport being configured to be coupled to an end effector that performs a work operation.

14. A bladder assembly for a hydraulic tool, the bladder assembly comprising: a reservoir defining an interior cavity configured to receive a hydraulic fluid; and a filler cap movably coupled to the reservoir, the filler cap defining a passage and including a control element movably disposed along the passage, the control element being movable between a first position to seal the inner cavity relative to the atmosphere and a second position to vent the inner cavity to the atmosphere to release the pressure within the bladder, the control element moving from the first position to the second position when the pressure in the bladder reaches a set pressure.

15. The bladder assembly according to claim 14, characterized in that The set pressure is an adjustable set pressure.

16. The bladder assembly of claim 14, wherein: The filler cap includes a handle coupled to the reservoir and a head extending from the handle to be manipulable by a user, the head including a first section of the channel extending toward a periphery of the head and toward the reservoir.

17. A power tool comprising: A housing including a battery receptacle; a drive unit disposed in the housing; a pump operably coupled to the drive unit to provide pressurized fluid; a trigger that allows a user to control the drive unit to operate the power tool; and A capsule assembly is disposed in the housing, the capsule assembly comprising: a reservoir defining an interior cavity configured to receive a hydraulic fluid; and a filler cap removably coupled to the reservoir, the filler cap defining a passage and including a control element movably disposed along the passage, the control element being movable between a first position to seal the interior cavity from atmosphere and a second position to vent the interior cavity to atmosphere to release pressure within the bladder when the pressure in the bladder reaches a set pressure.

18. The power tool according to claim 17, wherein: The filler cap extends outside the housing to allow a user to change the set pressure.

19. The power tool according to claim 17, wherein: The power tool includes a manifold having a work port coupled to an end effector that performs a work operation.

20. The power tool according to claim 17, wherein: The bladder includes a mounting bracket coupled between the reservoir and the filler cap, the mounting bracket being coupleable to the housing.

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