MIL-PRF-22710 Switches, Code Indicating Wheel \(Printed Circuit\), Thumbwheel And Push-Button, General Specification ForThis specification covers the general requirements for illuminated and non-illuminated, thumbwheel \(see 6.4.1\), and push-button, printed circuit rotary switches having unsealed and sealed modules and the associated hardware. These switches are designed for low power alternating current \(ac\) and direct current \(dc\) switching applications for use in electronic and communication equipment. Procurement of switches and mounting hardware will require additional data, giving detailed electrical and mechanical requirements, tolerances, and applicable additions and exceptions to the general requirements and tests specified herein \(see 6.2\).

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MIL-PRF-22710H

4.5.5.2 Operating force (applicable to switch modules or stacked switch modules, see 3.8.2). Thumbwheel

switches shall be tested by applying the specified force (see 3.1 and 6.1) tangentially to the thumbwheel of the

switch, parallel to the mounting surface.

4.5.6 Stops (when applicable, see 3.1 and 6.1) (see 3.9). Switches shall be tested in accordance with 4.5.6.1 as

applicable.

4.5.6.1 Thumbwheel switches. Unless otherwise specified (see 3.1 and 6.2.2), a tangential force of 15 pounds �1

pound shall be applied first in an upward direction, then in a downward direction.

4.5.7 Thermal shock (see 3.10). Switches shall be tested in accordance with method 107 of MIL-STD-202. The

following details shall apply:

a. Test-condition letter:

A: For switches with temperature-life characteristic letter B and letter C.

B: For switches with temperature-life characteristic letter A and letter D.

b. Measurements before and after cycling: Not applicable.

After the test, switches shall be examined for mechanical and electrical damage, loosening of rivets, and other

fastening devices.

4.5.8 Terminal strength (applicable to switches having solder-type terminals, see 3.1 and 6.2.2) (see 3.11). Where

the circuit configuration permits, the following minimum number of terminals shall be tested:

a. Three terminals per section, one section per switch for multisection switches.

b. Four terminals for single-section switches.

c. All terminals of the electrical-mechanical-actuator device (when applicable, see 3.1 and 6.2.2).

Two of the terminals shall be adjacent at minimum spacing and located on opposite sides of a throughbolt, if used,

where the circuit configuration permits.

4.5.8.1 Pull (see 3.11.1).

4.5.8.1.1 Terminals (except flexible wire leads). Unless otherwise specified (see 3.1 and 6.2.2), a force of 15

pounds �1 pound shall be applied to the terminals at the normal location for attaching lead wires. The pull force shall

be gradually applied to each terminal and maintained for 15 seconds minimum in each of three mutually

perpendicular directions as follows:

a. In a direction parallel to the plane of the section and perpendicular to the longitudinal axis of the terminal.

b. In a direction along the longitudinal axis of the terminal.

c. Perpendicular to the plane of the section in a direction in which there is minimum support provided by the

insulation.

4.5.8.1.2 Terminals (flexible wire leads). The pull test shall be the same as 4.5.8.1.1, except pull force shall be as

specified (see 3.1).

4.5.8.2 Bend (when applicable, see 3.11.2). Terminals bent permanently out of position as a result of the pull test

(see 4.5.8.1), shall be tested in accordance with method 211 of MIL-STD-202. The following details and exception

shall apply:

a. Test-condition letter: B.

b. Number of bends: Two.

c. Direction of applied force: Perpendicular to the plane of the section in a direction in which there is minimum

support provided by the insulation.

After this test, switches shall be examined for evidence of breakage of terminals and visible cracks in either the

terminals or the insulating material.