2. In many cases the maximum load-induced pressure … In its second position, the four-way valve connects the source of pressurized fluid to the second chamber and vents the first chamber, causing the piston to move in the opposite direction. When the poppet 38 engages the seat 37a under the urging of the spring 39, fluid communication is prevented between the chamber 36 and the chamber 32. In the counterbalance mode, the pilot pressure in chamber 41 acts all of the time against the bias of spring 39 only and not against the controlled pressure, thus providing repeatable, consistent operation regardless of the controlled pressure. 1. The counterbalance valve uses a pilot signal, usually from the inlet of the cylinder, to assist in opening a poppet. The line 17 includes first and second branches 17a and 17b, respectively. Every attempt has been made to ensure these calculations are accurate. Figure shows the internal construction of counterbalance valve. © 2004-2021 FreePatentsOnline.com. The dynamic performance of a balance valve is many times better than the dynamic performance of a pilot operated check valve . The valve applies a balanced piston design allowing relief operation at the valve setting independent of back-pressure at 2. The tank port T of the holding valve 20 is connected through a line 23 to the tank 11. If this occurs, the holding valve prevents any hydraulic fluid from flowing in or out of the cylinder chambers, thereby locking the piston within the cylinder and preventing the load from falling. 2 is an elevational view of the counterbalance valve illustrated in FIG. 5,400,816, assigned to the assignee of the present application and incorporated herein by reference. 6. 5. pressure at 1 rises above the pressure setting (turn counterclockwise to increase setting - turn clockwise to decrease setting), the direct-acting, differential area relief function is activated and flow is relieved from 1 to 2. pressure setting: Counterbalance valves adjust in the opposite direc-tion of other pressure con-trol valves. 3. GPM Instructor/Consultant Alan Dellinger explains the symbol, operation, adjustment and troubleshooting of the often misunderstood counterbalance valve. Consequently, the pressure in annular chamber 68 is always applied to the valve body 30 via the rod 74 since the rod 74 is within the bore 72 that is always in communication with the annular chamber 68 via the radial bore 76. The two-stage valve has overcome many instability problems by preventing the total decay of the stored energy in the cylinder and stopping the valve overreacting. 2 and 3) into sealing engagement with a seat 37a (see FIG. The four-way valve usually has three operating positions. No. 4. During normal operation, the pilot pressure on line 40 in chamber 41 controls the amount that the poppet valve 38 opens against the bias of coil spring 39. The hydraulic operating systems of backhoes and similar machines typically include a source of pressurized fluid which is selectively connected to a cylinder containing a movable piston. Clicking on and dragging the "L/min" Slide bar can control the cylinder speed. Other aspects and advantages of this invention will become apparent to those skilled in the art from the following detailed description of the preferred embodiment, when read in light of the accompanying drawings. In its first position, the four-way valve connects the source of pressurized fluid to the first chamber and vents the second chamber, causing the piston to move in one direction. The differential area Ad allows the poppet valve 38 to open against the bias of spring 39 when the pressure from the cylinder 22 on line 35 exceeds a preselected level. Counterbalance valve. A radial bore in 76 in the first cylindrical portion 62 intersects the axial bore so that the axial bore 72 is connected to the annular chamber 68 in the cage 37. The valve’s primary port is connected to the cylinder’s rod end, and the secondary port to the directional control valve (Fig. This invention allows the relief setting and operation to be controlled accurately and reliably in a counterbalance or "holding" valve. Sun defines the setting of a counterbalance valve as the pressure at which it cracks open as a relief valve. In most hydraulically operated machines which perform lifting functions, a holding or counterbalance valve is connected in the hydraulic lines extending between the four-way valve and the cylinder, typically directly adjacent to the cylinder. To accomplish this, backhoes are provided with articulated shovel assemblies which are moved by hydraulic operating systems. Counterbalance valve pilot cracking pressure calculator. By virtue of this arrangement, control fluid pressure is applied via the rod directly to the valve body in which the poppet valve element and cage are mounted. With pilot pressure at 3, the pressure setting is reduced in proportion to the stated ratio of the valve, until fully open with free- flow from 1 to 2. With pilot pressure at 3, the pressure setting is reduced in proportion to the stated ratio of the valve, until fully open with free-flow from 1 to 2. As is well known in the art, the four-way valve 15 is selectively moved so as to cause the piston 25 to move relative to the cylinder 22, thereby moving the member connected to the rod 26. The best way to check the setting is to remove the valve from the circuit. This is likely to be about 30% of the load induced pressure but check the valve manufacturer recommendations. Counterbalance valves should be set at least 1.3 times the maximum load induced pressure. 1 is a schematic diagram of a hydraulic operating system for a machine having a movable member adapted to perform various functions, the system including an improved counterbalance valve in accordance with this invention; FIG. 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