TM 55-203
CHAPTER 7
COUPLERS
7-1. General
Automatic couplers such as the type E, in general use in
North America, are completely automatic except for
aligning the knuckle to receive the mating knuckle of the
car to be coupled It is safely operated from alongside the
car by raising the uncoupling lever. Type D and type E
couplers can be rigged for either bottom or top operation,
according to the location of the lock lifting device on the
Figure 7-1. Typical type "D" coupler (rigid shank).
car. Type D couplers may be found on pre-1933 cars in
CONUS, although they are no longer acceptable in
designed that only the actuating parts need to be changed
interchange. They may be used on intrainstallation cars
in order to fit the coupler for either top or bottom (rotary)
in CONUS and on US built equipment in other countries.
operation. The uncoupling lever is simplified and can be
Type H, swivel shank (tightlock) couplers are in general
located in any position that is convenient to trainmen for
use only on passenger equipment All automatic couplers
easy operation. A typical type E coupler is depicted in
are similar in components and methods of operation. The
working parts of D and E couplers are interchangeable;
however, with the exception of the knuckle pin, no parts of
b Component Parts. Type E couplers consist of the
the type H coupler are interchangeable with any other
following components, which function as indicated
type, although the parts have the same names. As it is
the most common CONUS type, only the type E is
(1) Body. This is the main section of the coupler
discussed in detail.
The Willison coupler, used
It consists of the coupler head, the horn, the guard arm,
extensively in foreign areas, is also discussed herein.
the shank, and the butt. The coupler head houses the
operating components.
7-2. Type D Coupler
(2) Knuckle. This is a rotating hook, hinged on
The basic components consist of the body, knuckle lock,
the knuckle pin, held to a connection with a rotating
knuckle thrower, and knuckle pin (fig 7-1). These parts
knuckle by the knuckle lock.
remain the same whether the coupler is top-operated or
bottom-operated. If equipped for top operation, the lifter is
(3) Lock. A key-shaped block which drops into
used in addition to these parts. If the coupler is rigged for
place when the knuckle is closed. It prevents uncoupling.
bottom operation, a lock lifter and toggle are used Pivot
lugs provide a bearing for the lifter. Because of the
(4) Knuckle thrower The device which throws
similarity of these parts with like parts of the type E, only
the knuckle open when the uncoupling lever is raised.
the latter type will be discussed herein.
(5) Knuckle pin. This acts as a pivot for the
7-3. Type E Coupler
knuckle and holds the knuckle pin in the jaws of the
coupler.
a General. The type E coupler is the type D with
(6) Lifter The mechanism which is moved by the
many improvements and refinements. It Is so
uncoupling lever to lift the knuckle lock and open the
knuckle.
(7) Toggle. This works with the lifter and pivot
lugs to provide a means of lifting the knuckle lock on
7-1
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