Figure 14. Focusing mechanism.

TM 11-6720-239-35

pressed, the following actions pertinent to the

1-7. Focusing Mechanism

shutter release occur:

a. General. The camera focusing mechanism is

(1) Force exerted on shutter release button

operated by the use of focus button 1 (right) and

2, transmitted through the cable assembly to the

focus button 1 (left). The two buttons are at-

shutter release tip, forces the shutter release tip

tached to opposite sides of the focus bar assembly.

up.

The focus bar assembly is connected to the inner

frame (top) by a detent slide. The inner frame

(2) As the shutter release tip travels upward,

(top), in turn, is connected by a shutter shaft

it forces normally open battery switch S1 to close,

sleeve to the shutter assembly. The inner frame

and trips the slide latch.

(bottom) is attached to the camera body and the

(3) Closing battery switch S1 completes a

shutter assembly by track guides. The U-frame

circuit which energizes the electromagnet. The

assembly attaches both the top and bottom inner

electromagnet now holds the closing blade in its

frames by means of link pivots. The three compo-

cocked position.

nents in turn serve to hold the shutter assembly in

(4) When the slide latch is tripped, the

cocking slide is released and snaps back to its

original position.

(5) As the cocking slide returns to its origi-

nal position, a roller on the slide strikes a tab on

the blade latch, forcing the blade latch down.

(6) As the blade latch is forced down, it re-

leases the opening blade, allowing it to snap for-

ward. Light now passes through the aperture and

the hole in the opening blade to expose the nega-

tive.

(7) As the blade latch releases the opening

blade, it also opens timing switch S2. The timing

circuit now begins to operate.

(8) When the average scene light has allowed

the photocell to pass the correct amount of cur-

rent through the timing circuit, the electromagnet

is deenergized and the closing blade snaps shut.

Figure 1-3. Shutter release mechanism.

Figure 14. Focusing mechanism.

1-3