TM 9-1375-213-12
(3) In attaching switch asaembly to rough or un-
NOTE
even surface, avoid bending ears of switch by over-
The coupling body is functionally inter.
tightening fasteners, (Bent ears will distort bore and
changeable with a standard coupling base
result in malfunctions).
b. General Procedures. The following are general
The coupling base is used in the same man-
procedures for setting up the firing device. Operators
ner as with other firing devices.
must refer to the detailed procedures (d below) for set-
(2) The coupling body is threaded on both end
ting up each specific mode of operation.
and contains a primer. The primer end screws into the
(1) Obtain necessary materials to set the firing de-
switch. The other threaded end is fitted with a formed
vice up for the desired mode of operation.
rubber gasket and a packing nut for use with nonelec-
(2) Inspect components of firing device to assure
tric blasting caps, or a time fuse. Removal of the pack
there are no obvious defects.
ing nut permits the coupling body to be threaded into
(3) Prepare coupling body for desired mode of
operation.
(a) For use with M700 time blasting fuse or oh
NOTE
style safety fuse.
Removal of the safety pin is the final step in
NOTE
all operating modes, If the safety pin is inad-
M700 time blasting fuse forms a water tight
vertently removed prior to step 10, stop all
seal with the coupling body, but the old style
safety fuse is not considered water tight due
ures (e) below.
to its corrugated surface.
(4) When required by the specific operating mode,
1. Remove packing nut and gasket from coup
set up and secure switch and accessories (tripwire, ten-
ling body.
ion release attachment etc.). Do not remove any pins
2. Cut and discard a 6-inch length from end of
at this time.
fuse roll, Cut fuse to desired length.
(5) Assure both round and square head pivot pins
3. Slide gasket and packing nut over end of
are in place. Check safety pin for ease of removal, As-
fuse.
sure legs of safety pin are straight. If legs are bent,
4. Push end of fuse into coupling body as fax
straighten and press them together with pliers.
as it will go.
(6) Screw coupling body into switch.
5. Thread on and tighten packing nut to se-
cure fuse.
(7) Connect charge to coupling body's cap or fuse
(b) For use with blasting cap.
or screw switch and coupling body into implanted
1. Remove packing nut and gasket from coup
nine or charge (Depending upon type of operation).
ling body.
(8) Lay out and tension tripwire or set up restrain-
2. Insert open end of blasting cap into coup
ing load, etc.
ling body and gently push it in as far as it will go.
WARNING
NOTE
If safety pin resists movement do not with-
draw. Firing pin may have been released re-
sary to gently force cap into coupling body.
check assembly. Disassemble and reset as ne-
This will bend the flared skirt of M7 caps
cessary (e(2) below)
slightly.
(9) Assure safety pin is in place, but can easily be
3. Slide gasket and packing nut over blasting
removed. Assure firing pin has not been released.
cap, thread on and tighten to secure.
check that any inadvertent action or small motion
cannot accidentally actuate switch.
NOTE
(10) Remove appropriate pin to set mode of switch
If the coupling body and blasting cap are to
operation.
be threaded (screwed) into a mine or demoli-
tion charge capwell, the packing nut and
WARNING
gasket are not required.
All personnel but the prime installer (opera-
d. Modes of Operation.
tor) should be evacuated from the area prior
(1) Pressure (fig. 2-38). In this mode of operation
to pulling the safety pin.
(11) Using a lanyard (length of wire or cord) to re-
applied to a pressure plate that is resting on the sear
move safety pin take cover and pull the safety pin.
plate. The switch setting instructions are as follows:
cave the area.
(a) Assure both round and square-head pivot
c. Use of Coupling Body or Coupling Base.
pins are in place, Check components to assure there
(1) Either a coupling body or a coupling base can
be used in conjunction with the M142 firing device.
are no obvious defects. Check safety pin for ease of
Change 5