Many nuts and bolts in Caterpillar machinery need to be tightened to high torque values. Some of these nuts and bolts are in areas where access space is limited. Regular torque wrenches, multipliers, and striker wrenches can be difficult and possibly a danger to use under limited access conditions. The 6V200 Hydraulic Wrench (Illustration 1), which needs less space to use than a torque wrench multiplier, is available to tighten or loosen fasteners.
Illustration 1. 6V200 Hydraulic Wrench
The 6V200 Hydraulic Wrench has a capacity of up to 2500 lb ft (3380 N·m) and a weight of 19.5 lbs. (8.8 kg). It has a wide range of service applications. Illustration 2 shows the wrench in position on a track roller mounting bolt.
Illustration 2. 6V200 Hydraulic Wrench In Position
Illustrations 1, 3, and 4 show the main components of the hydraulic wrench. The ratchet inside the lever arm is made from two pawls and a large-tooth gear. As the hydraulic cylinder pushes the lever arm forward, one of the pawls engages the gear. This moves the square driver around. The other pawl prevents backward movement of the gear. Each cycle moves the square driver through approximately 40° of rotation. The wrench can be positioned to either loosen or tighten fasteners.
The 6V200 Hydraulic Wrench comes equipped with the standard 6V2081 Long Square Driver. A short 6V2079 Driver is also available for applications where access space is even more limited. The set screw shown in Illustration 4 controls the position of the square driver. Illustration 5 shows both the long and short square drivers. Both drivers are designed to be used with 1" (25.4 mm) sockets.
One side of the wrench frame has six scribe marks machined into the sleeve around the square driver. These scribe marks can be seen in Illustration 3. After the application of the correct torque, the operator can use a grease pencil and make marks to show the extra turns that are needed. The wrench is then activated until the scribe and grease pencil marks are in alignment.
As the wrench loosens or tightens a fastener, the two internal pawls will "click" as they fall into place. This sound is an indication that the hydraulic cylinder has made a complete cycle (either to loosen or to tighten) and is ready for another cycle to begin. Also, the cylinder rod guard (Illustration 3) has two indicator holes through which the color red can be seen when the cycle is complete.
Illustration 3. 6V200 Hydraulic Wrench Components
To get up to 2500 lb ft (3380 N·m) of torque, the 6V200 Hydraulic Wrench needs 6000 psi (41,500 kPa) of hydraulic oil pressure from the pump. To prevent damage to the wrench from too much oil pressure, a bleed valve on the wrench will leak oil if the pressure is greater than 6200 psi (42,880 kPa).
Illustration 4. 6V200 Hydraulic Wrench Components
Illustration 5. 6V200 Hydraulic Wrench Square Drivers
Illustration 6 shows the reaction arm with the eight position holes drilled into the upper end. The arm can be moved either left or right or behind the wrench frame and locked into position to provide a point of resistance for the torque force.
Illustration 6. 6V200 Hydraulic Wrench Reaction Arm.
The 6V200 Hydraulic Wrench is equipped with the 1P2375 Quick Disconnect. This quick disconnect permits the wrench to be used with any existing Caterpillar Service Tool Hydraulic Pump.
Torque/Pressure Conversion Decal
Since the torque force changes directly in relation to the amount of hydraulic oil pressure, a decal with conversion units is put on the wrench frame. This decal, Form No. SEHS7611, gives correct psi for the needed torque value in lb ft.
The 6V200 Hydraulic Wrench can be used with any existing Caterpillar Service Tool Hydraulic Pump. The pumps and their specification are listed below.
All of these pumps have a capacity of 10,000 psi (69,000 kPa) and are equipped with a 3-position manual 4-way valve.
If a series of fasteners is to be loosened, set the relief valve on the hydraulic pump at 6000 psi (41,500 kPa). This gives maximum torque to the wrench to loosen the fasteners. If a series of fasteners is to be tightened, set the pump relief valve so that the pump pressure will not give a greater torque value than desired. Use the conversion decal to find the correct pump psi setting for the desired torque. The wrench can then be used without having to check the pressure gauge constantly for the correct psi indication. More complete instructions on the use of the wrench are given in Special Instruction, Form Number SMHS7657.
In addition to both square drivers, the 6V2080 Seal Kit is also available if needed for service of the hydraulic cylinder.