The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 09, 1991
Filed:
Jan. 31, 1990
John W Smith, Indianapolis, IN (US);
James P Meagher, Indianapolis, IN (US);
Emhart Industries Inc., Farmington, CT (US);
Abstract
A housing includes a switch chamber and a plunger chamber communicating with the switch chamber. A plunger is slidable within the plunger chamber. Cam surfaces on the plunger operate electrical switches in the switch chamber. There is an axial channel in the plunger, and a slot through the plunger wall communicates with the channel. A vacuum passageway passes from one side of the housing, into the channel, and a solid extension of the passageway passes through the slot, and into a hole in the opposite wall of the housing. As the plunger moves in and out, the slot slides on the extension to guide to stabilize the plunger. A vent hole in the vacuum passageway opens into the channel. A sealing member slides in the channel along the axis of the plunger, alternately sealing and unsealing the vent hole as the plunger moves. A spring seated between the plunger and the sealing member permits the plunger to continue moving when the sealing member is seated in the passageway vent hole. A maze causes air passing through the switch chamber to the vent hole to turn and slow, thereby causing dust particles to settle out of it.