THREE-WAY LOCKING FASTENERS

There are times when you need to use a snap fastener that has extra security. When you must have this type of fastener, you should use either the three-way locking snap or the curtain fastener.

THREE-WAY LOCKING SNAPS

The three-way locking snap is stocked in one size only-regular. It is used on fight clothing,

CURTAIN FASTENER

Figure 10-16.-Three-way locking snap-type fastener.

parachute containers, and back pads. (See figure 10-16). This fastener opens only when lifted from the side, with the dot located on the top of the button. When installing this snap fastener, you should ensure that you install the three-way locking snap in the position that you want to be opened. This type of snap should never be used where any quick-opening devices or quickreleasing action is required.

The curtain type fastener (lift-the-dot) is stocked in two sizes-large and small. (See figure 10-17). These fasteners have many uses, especially for truck and boat covers. The small lift-the-dot is the same as the large one, and designed on a smaller scale for use on lighter work where the bulkiness and weight of the large lift-the-dot are not desired.

INTERLOCKING SLIDE FASTENERS

Tasks are accomplished more easily and quickly through the use of interlocking fasteners. For example, they save precious seconds for an aircrewman when he is donning his flight clothing or exposure suit. These fasteners also provide the repairman with a means of easy access to items that require inspections.

The types of interlocking slide fasteners (zippers) used on flight clothing and other items of aviation equipment are shown in

Figure 10-15.-Large curtain-type fastener (lift-the-dot).

Figure 10-18.-Slide fasteners.

Figure 10-19 shows the parts of an interlocking fastener.

Interlocking Slide Fastener Construction

An interlocking slide fastener consists of two chains of teeth (hollow cones or scoops) facing each other. When brought together at the proper angle, each tooth fits within the scoop of the tooth opposite it.

When closed, the interlocking slide fastener teeth cannot be parted except through the use of the slider, which, when moved, displaces teeth at the proper angle for meshing and unmeshing. The small clips (stops) at the top and bottom of the interlocking slide fastener are designed to prevent the slider from running off the track. Separatingtype slide fasteners do not have a bottom stop, but are equipped with a pin on one side and retainer arrangement on the other to allow the two parts of the slide fastener to separate.