APPARATUS FOR DETECTING INTERRUPTION IN THE CYCLIC MOVEMENT OF A MEMBER

• US 3,701,139 A
• Filed: 09/17/1970
• Issued: 10/24/1972
• Est. Priority Date: 09/17/1970
• Status: Expired due to Term

• Current Assignee: Mestek Incorporated
• Original Assignee: Walter R. Creuz
• Inventors: Creuz, Walter R.
• Primary Examiner(s): Caldwell, John W.
• Assistant Examiner(s): Slobasky, Michael
• Application Number:
  US05/073,057
• Time in Patent Office: 768 Days
• Field of Search: 340/271,58,309.1 324/168
• US Class Current: 340/671
• CPC Class Codes: G01P 13/00 Indicating or recording presence, absence, or direction, of movement electric switches H01H; counting moving objects G06M7/00

Abstract

A single-pole double-throw magnetic reed switch responds to the passage of one or more magnets on the periphery of a rotating air-to-air energy exchange wheel to signal through an interval timing circuit any interruption in wheel rotation even if a magnet stops adjacent the switch. Actuation of the reed switch couples a voltage pulse from a charge storage capacitor to a transistor for resetting the timing circuit to start another timing cycle. If a subsequent actuation of the switch does not occur before the timing circuit completes a timing cycle, the signalling device is energized.

Claims

1. Apparatus for detecting an interruption in the rotation of an air-to-air energy exchange wheel comprising in combination, a small magnet arranged to be secured to the periphery of said wheel, a reed switch having first and second fixed contacts and one magnetically moveable contact, the moveable contact being biased to normally engage said first fixed contact, but being actuable by the magnetic field from said magnet when the magnet is in close proximity to said switch to disengage said first fixed contact and engage said second fixed contact, means for counting said reed switch adjacent the periphery of said wheel in close proximity to the path of said magnet, a source of D.C. voltage connected between said first fixed contact and a point of reference potential, means for storing a voltage charge connected between said moveable contact and said point of reference potential, a resistor connectible in series between said means for storing a voltage charge and said source of reference potential by said moveable contact upon actuation thereof to provide a first resistance-capacitance timing circuit, a second resistance-capacitance timing circuit connected between said source of voltage and said point of reference potential, a current control device coupled across said capacitance for discharging said capacitance when said device is conductive, said device having control means for controlling the conductivity thereof, means connecting said second fixed contact to said control means, a current switching device, a signalling device, means connecting said signalling device under the control of said current switching device to a source of energizing current, and means connecting said capacitance to said current switch device for cAusing said switching device to conduct when the voltage across said capacitance exceeds a predetermined magnitude.