SPROCKET 2D3166 - Caterpillar

Illustration 1 g00732831
Location of Variable Pressure Reducing Valve (1) Variable pressure reducing valve. (2) Solenoid valve (delimbing knives). (3) Solenoid valve (holding arms or feed roller arms).The maximum pressure to the delimbing knives, the feed roller arms, and the holding arms is controlled by the signal limiter valves in the main control valve. On the HH45, the pressure to the delimbing knives and the feed roller arms can be lowered below the maximum pressure while a tree is processed. On the HH55/HH65/HH75, the pressure to the delimbing knives and the holding arms can be lowered below the maximum pressure while a tree is processed. This is accomplished with variable pressure reducing valve (1) .Variable pressure reducing valve (1) can reduce the pressure in the corresponding circuits by 0 to 7000 kPa (0 to 1000 psi). The pressure reduction is accomplished by draining off oil from the cylinders with a proportional solenoid valve. As the solenoid valve continues to move, more oil drains off and the pressure continues to decrease. This pressure reduction is known as the "pressure window".
Illustration 2 g00733364
Schematic of Variable Pressure Reducing Valve (1) Variable pressure reducing valve. (2) Solenoid valve (delimbing knives). (3) Solenoid valve (holding arms or feed roller arms). (4) Orifice. (5) Orifice. (A) Signal line from main control valve (delimbing knives). (B) Signal line from main control valve (feed roller arms or holding arms).Variable pressure reducing valve (1) consists of two proportional solenoid valves. Solenoid valve (2) controls the pressure reduction in the delimbing knife circuit. Solenoid valve (3) controls the pressure reduction in the feed roller arm circuit on the HH45. Solenoid valve (3) controls the pressure reduction in the holding arm circuit on the HH55/HH65/HH75. Variable pressure reducing valve (1) contains an orifice for signal line (A) and signal line (B). Orifice (4) maintains the minimum pressure of the load signal from the delimbing knife circuit. Orifice (5) maintains the minimum pressure of the load signal from the feed roller arm circuit or the holding arm circuit.
Illustration 3 g00732962
Graph of Cylinder Pressure (Delimbing Knife) (AA) Pressure window. (BB) Pressure setting from the measuring and control system. (CC) Pressure setting from the potentiometers.When the harvester head clamps onto a tree before felling, the pressure to the delimbing knives, the feed roller arms, and holding arms is at the maximum pressure. The maximum pressure to these functions is controlled by the signal limiter valves in the main control valve. After the tree is felled and while the tree is fed in either direction, the settings of the potentiometers and the programmed settings of the measuring and control system can be used to lower the pressure in these circuits.Illustration 3 is an example of the delimbing knife circuit of an HH65. The signal limiter valve of the CLOSE function is set to 12500 kPa (1800 psi). The pressure window in the measuring and control system is programmed to 7000 kPa (1000 psi).As the tree begins to feed through the harvester head, the measuring and control system