TM-9-2350-311-34-2

TM-9-2350-311-34-2 - Page 33 of 552

TM 9-2350-311-34-2

1-14.2 Location and Description of M178/M182 Mount

The M178/M182 mount attaches the 155mm cannon to the vehicle cab. It permits the 155mm cannon to be elevated or

depressed within prescribed limits and to slide rearward and forward on machined surfaces during recoil and counter recoil

cycles. Major components of the M178/M182 mount are as follows:

Cradle. The cradle assembly (1) is a machined casting in which the 155mm cannon rides and which carries the compo-

nents of the variable recoil system, operating cam (2), trunnion roller bearings (3), and recuperator cylinder (4).

Operating Cam. The operating cam (2) is a flat plate with cam paths machined into it and is hinged to the cradle assem-

bly (1). The operating cam assists in unlocking and opening breechblock assembly (5) and holds it open after the

weapon returns to battery. When the operating cam is lifted manually from contact with operating crank assembly (6),

the breechblock assembly is allowed to close and lock automatically.

Trunnion Roller Bearings. Trunnion roller bearings (3), mounted on the sides of cradle assembly (1), are attached to

the cab by trunnion brackets and caps and carry the weight of the cannon and mount. This permits the cannon to be

elevated and depressed within limits set by stops welded to the mount.

Upper and Lower Rotors. The upper gun rotor (7) and lower gun shield (8) are heavy aluminum plate extensions bolted

to the gun shield. These aluminum plates function to provide protection from the effects of enemy fire.

1-13