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| Illustration 1 | g02456799 |
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Hydraulic hammer (Typical Example) | |
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| Illustration 2 | g02802336 |
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(1) Accumulator
(2) Tie rod (3) Control valve (4) Seal carrier (5) Front Head (6) Bushing assembly (Lower) (7) Bushing (Upper) (8) Thrust ring (9) Cylinder (10) Piston (11) Plug (Automatic shutoff passage) | |
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| Illustration 3 | g02456836 |
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(3) Control valve
(12) Pressure control valve (13) Check valve (14) Main spool (15) Large spool (16) Small spool | |
The Hydraulic Hammer provides energy for impact through a system of valves in order to break materials. The valves coordinate the motion of a piston which strikes the tool bit of the hammer which transfers energy in order to break materials.
Hydraulic power is supplied by the auxiliary hydraulic system of the host machine. Refer to the Service Manual, "Hydraulic Oil Flow - Test" for the operating parameters of the auxiliary circuit. The auxiliary hydraulic system supplies the flow and the pressure to control valve (3) of the hammer through the connecting lines.
Control valve (3) contains the following components: pressure control valve (12), check valve (13), main spool (14), large spool (15) and small spool (16). Pressure control valve (12) is located below the return port "OUT" on the valve body of the hammer.
Pressure control valve (12) regulates the operating pressure of the hammer to a preset pressure. Pressure control valve (12) regulates the charging circuit of accumulator (1) in order for the optimum accumulator pressure to be attained before the hammer starts a down stroke of piston (10). Once the correct pressure in the hammer is reached, pressure control valve (12) will open in order to allow fluid at the top of piston (10) to be cycled to the return port. This action will initiate an upward stroke of piston (10). The operating cycle will begin.
Pilot pressure is directed to large spool (15) as the piston moves upward. Since large spool (15) is larger than small spool (16), hydraulic force moves main spool (14) in order to redirect the incoming oil and the oil from accumulator (1) to the top of piston (10). The spool movement will start the impact stroke of the hammer. The position of main spool (14) coordinates the movement of piston (10) during hammer operation. The alignment of piston (10) is maintained by cylinder (9) and seal carrier (4).
Check valve (13) maintains a pressure level within the hammer in order to keep the intermittent start-up smooth. Check valve (13) reduces pressure pulsations from passing into the pressure connection of the hammer and from affecting the host machine.
Proper alignment of the tool is maintained by the upper tool bushing and the lower tool bushing. Proper alignment is critical in preventing damage to the hammer. Refer to Service Manual, "Tool Bushing (Lower)" for information regarding wear limits. Refer to Service Manual, "Hydraulic Hammer" for information regarding wear limits. The tool is positioned within the hammer for impact by thrust ring (8) to ensure that each impact is properly timed.
The automatic shutoff operation occurs when the tool bit is not in contact with the material that is being broken. This condition prevents the tool from being fully engaged with thrust ring (8) which causes piston (10) to be in a position that is lower than the standard position. The automatic shutoff operation can be disabled by installing a setscrew under plug (11).
Proper structural alignment of the hammer is maintained by a tension load on tie rods (2).