TM 55-203
Figure 7-2. Typical type "E" coupler
c. Operation. To throw the knuckle (i.e., uncouple),
7-5. Maintenance, CONUS-Type Couplers
the lock is lifted above its lockset position until the
fulcrum on the forward side contacts the shoulder within
a. General. Design specifications, requirements, and
the coupler head.
This contact stops the vertical
regulations will dictate when and what coupler
movement of the lock and forces it to rotate about its
maintenance action is to be accomplished. For CONUS-
fulcrum, thus giving the lock key a positive movement to
type couplers previously discussed, two of the more
the rear. This rotates the knuckle thrower about its
frequent requirements for maintenance are cited below.
trunnions, and the lip of the thrower contacts the shoulder
Familiarity with AAR rules and Army regulations, as well
on the underside of the knuckle, throwing the knuckle
as with parts and their operational functions, is essential
open, or unlocking It, if coupled to another.
for good maintenance. Frequent inspections will detect
defective parts. Couplers, types D and E with distance
7-4. Tightlock Couplers
between point of knuckle and guard arm exceeding 5 5/16
inches as measured by gage (fig 7-3), must have the
defective part or parts renewed to bring coupler within
The type H or tightlock coupler, of entirely new design,
required gage of 5 1/8 inches as measured by gage (fig 7-
incorporates a number of distinct new features. In
4). If coupler is out of gage, the body must not be
outward appearance, it is similar to those discussed and
renewed unless the application of second-hand,
consists of essentially the same named parts (para 7-2).
reconditioned, or new knuckle lock and pin, any or all, will
Certain surfaces of the coupler head knuckle, lock and
not bring it within the required gage of 5 1/8 inches.
knuckle pinholes in both head and knuckle are machine
b.
Coupler Height.
Coupler height must be
finished to meet the close fitting tolerances required. In
addition, aligning wings extend from both sides of the
maintained within the proper limits. The height of a
coupler head. These form a part of the head and provide
coupler is measured from the top of the rail to the center
increased coupling efficiency. This type of coupler is
of the face of the coupler knuckle. Empty freight cars with
rotary-operated and normally operated from the left side
coupler heights measuring 32 1/2 inches or less will be
of the car by a single-type lock-lift assembly. It can be
adjusted to 34 1/2 inches. Loaded freight cars with
adapted to a double-type lock-lift assembly for operation
coupler heights measuring 31 1/2 inches or less will be
from either side. The principal advantages of this coupler
adjusted to, but will not exceed, 33 1/2 inches. When
design are the reduction of contour -slack, elimination of
adjusting coupler heights, the coupler should first be
noise caused by coupler slack, the reduction of fatigue
placed in proper alinement with draft gear. Shim of 1/4-
failures in the coupler face and knuckle wall, and
inch thickness or more, as required, may be applied to the
elimination of buffing stresses. Since slack is reduced
carrier iron to adjust coupler height. If a shim less than
and resulting buffing and jolting is also reduced, the
1/4inch thickness is required, realignment is unnecessary.
service
lift
of
the
coupler
is
increased.
After the coupler has been placed in
7-2
Previous Page
