Non-locking switch for filter monitoring

• US 20060225993A1
• Filed: 01/30/2006
• Published: 10/12/2006
• Est. Priority Date: 01/28/2005
• Status: Active Grant

• Current Assignee: Donaldson Company Incorporated
• Original Assignee: Engineered Products Company (Donaldson Company Incorporated)
• Inventors: Berry, Charles H. III, Heuthorst, Joseph P., Lockert, Michael J. Jr.
• Granted Patent: US 7,414,207 B2
• Time in Patent Office: Days
• US Class Current: 200/83.J
• CPC Class Codes: B01D 46/0086 Filter condition indicators
• CPC Class Codes: F02M 35/09 Clogging indicators ; Diagnosis or testing of air cleaners sensors therefore F02M35/10373
• CPC Class Codes: H01H 35/2685 Means to protect pressure sensitive element against over pressure
• CPC Class Codes: H01H 35/346 in which the movable contact is formed or directly supported by the diaphragm
• CPC Class Codes: H01H 9/047 provided with venting means

Abstract

Commercially available filter-monitoring switches suffer from problems related to over sensitivity and reliability. Accordingly, the present inventors have devised, among other things, various embodiments of filter-monitoring switches and related components, subassemblies, methods, and systems. One exemplary filter-monitoring switch includes a diaphragm operably couple to move a conductive element back and forth between a pair of fixed terminals in response to pressure differences across the diaphragm. The conductive element is mounted to an insulative pin of substantially uniform width, and the terminals include leaf contacts that constantly engage the pin or the contacts throughout normal operation of the switch, thereby reducing flexure of the contacts and effectively providing a self-cleaning and self-healing electrical switch.

Claims

1. A filter-monitoring switch comprising:

first and second contacts for connection to an electric circuit;

a conductive member for electrically coupling the first contact to the second contact; and

a diaphragm coupled to move the conductive member.

2. The filter-monitoring switch of claim 1 further comprising:

a push plate coupled to the diaphragm and having a central pin coupled to the conductive member.

3. The switch of claim 2, further comprising a guide structure having a hole through which the central pin extends, the guide structure fixed relative to the first and second contacts to guide movement of the central pin along an axis between the first and second contacts.

4. The switch of claim 2, wherein the conductive member is cylindrical and encircles a portion of the central pin.

5. The switch of claim 1, wherein further comprising first and second terminals that are electrically and mechanically coupled respectively to the first and second contacts;

and

a terminal support structure that is insert-molded around the first and second terminals.

6. The switch of claim 3, wherein the terminal support structure includes a sleeve around the first and second terminals, with the shroud including a notch generally parallel to the first and second terminal.

7. The switch of claim 1, wherein each of the first and second contacts includes leaf contact biased toward the conductive member.

8. The switch of claim 1, further comprising a Teflon filter and a cover.

9. A method of operating a filter-monitoring switch, the method comprising:

electrically coupling first and second contacts by moving a conductor along an axis between the first and second contacts in response to a differential pressure condition.

10. The method of claim 9, wherein moving the conductor along the axis comprises flexing a diaphragm that is mechanically coupled to the conductor.