Title: Switch assembly having movable contact face configuration for penetrating frost or ice layer on adjacent contact surface

Abstract: A pneumatic cylinder-piston door operator is connected to an air supply by a solenoid actuated valve. A control circuit selectively energizes the solenoid valve in response to momentary actuation of switches including control and safety switches. For refrigeration unit installation, the switch contacts are formed with one contact having a pimpled surface and the other contact having a serrated surface to provide a reliably electrical connection. For the manual control switches, a micro-switch is mounted in a suitable enclosure with appropriate gaskets to minimize the effect of adverse environmental conditions. A spring-loaded plunger is mounted within the housing and provided with an external push-button or pull cord actuator.

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Inventors: Runft, Arthur J. (Mequon, WI, US)

Application Number: 629057
Filing Date: 1975-11-05
Publication_date: 1978-02-14
Assignee: Kelley Co., Inc. (Milwaukee, WI)
Primary Class(es): 200/279 200/52R, 200/237, 200/239, 200/244
Other Classes:
US Patent Ref:

1892008	Dec, 1932	Ross	200/244.
2490020	Dec, 1949	Enzler	200/242.
2788420	Apr, 1957	Mathews et al.	200/279.
3168165	Feb, 1965	Bagnusco	200/61.
3297851	Jan, 1967	Jaquet	200/244.
3531799	Sep, 1970	Rendler	200/253.
3842221	Oct, 1974	Dayet et al.	200/52.
3922814	Dec, 1975	Runft	200/279.

Other Refs:
Primary Examiner: Scott, James R.
Assistant Examiner:
Attorney: Andrus, Sceales, Starke & Sawall