Torque limiting card loks by Schroff perfectly suit field-level maintenance

Gould Fasteners carries Schroff's toque limiting card loks.

As a leader in electronics packaging design and fabrication, Schroff manufactures many innovative products – including its wide range of card loks, available in Canada from Gould Fasteners. This includes torque limiting card loks, commonly used in the aerospace and military sectors.

Schroff’s torque limiting card loks are ideal for field-level maintenance applications, as users need no specialized tools or technical knowledge to install them properly. Like other card loks, they are designed to retain polychlorinated biphenyls (PCBs) in rugged, high-shock, and high-vibration conditions.

No torque wrench required

Gould’s inventory of Schroff torque limiting card loks includes the manufacturer’s Series 223 and 224. These card loks are simple to install, without a torque wrench. The user uses an integrated torquing mechanism and turns the hex wrench until three clicks indicate optimal clamping and thermal transfer performance. These two lok series also stand out by minimizing the chances of insufficient board retention from under-torquing, as well as damage to boards and cold walls from excessive torquing.

Similar to Schroff’s other card and wedge loks, Series 223 and 224 are screw-actuated and have hex screw heads. Aside from PCB retention, they also assist in thermal transfer from PCBs to cold walls with conduction by improving the interface between the PCBs and chassis rails.

Torque limiting card loks are perfectly suited to military and aerospace applications that have critical performance requirements and involve high shock or vibration. Schroff also recommends them for applications that benefit from the loks’ simple installation, that require high equipment availability, or in which downtime is expensive.

The Series 223 card lok has a profile of 5.72 by 6.86 millimetres (mm), a minimum expansion of 8.26 mm, and an average clamp force of 263 pounds. Each Series 224 lok has a profile of 5.33 by 7.24 mm, a minimum expansion of 8.64 mm, and an average clamp force of 236 pounds. Both types measure 97 to 325 mm, with 12.7-mm increments, and weight 1.12 grams per centimetre; they include flexible mounting options and five-segment, non-shafted designs and are available with a variety of finishes.

To learn more, contact Gould.

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