ROLLER BEARING DISCRIMINATOR FOR A RAILROAD HOT BOX DETECTOR SYSTEM

• US 3,812,343 A
• Filed: 08/27/1973
• Issued: 05/21/1974
• Est. Priority Date: 08/27/1973
• Status: Expired due to Term

• Current Assignee: Arthur J. Glazar, Cornelius A. Gallagher
• Original Assignee: Arthur J. Glazar, Cornelius A. Gallagher
• Inventors: Gallagher, Cornelius A., Glazar, Arthur J.
• Primary Examiner(s): Ward, Jr., Robert S.
• Application Number:
  US05/391,529
• Time in Patent Office: 267 Days
• Field of Search: 246/169D,169A,169R 340/231 73/9
• US Class Current: 246/169.00A
• CPC Class Codes: B61K 9/06 by detecting or indicating heat radiation from overheated axles

Abstract

A circuit is provided for distinguishing electrical signals generated by a hot box detector scanner in response to a passing roller bearing from those generated in response to a passing friction bearing. The circuit includes first and second capacitors for storing the maximum amplitude of each output signal wave from the scanner and for storing the maximum amplitude of each wave at a predetermined point. The ratio of the charges stored on the capacitors is then obtained. It has been found that for a roller bearing this ratio should approach unity while for a friction bearing the ratio is not close unity.

Claims

1. In a railroad hot box detector system of the type including:

heat responsive scanner means associated with a first rail of a section of track adapted to scan the bearings of a railraod car along said rail and generate an output signal in response thereto having an amplitude and wave form indicative of the temperature and type of bearing scanned and sensor means adapted to generate a first signal when a bearing enters the field of view of said scanner and a second signal when The bearing leaves the field of view of said scanner, the Improvement comprising circuit means for discriminating between said types of bearings, said circuit comprising;

means for generating a third signal intermediate in time to said first and second signals;

first storage means connected to the output of said scanner for storing a charge indicative of the maximum amplitude of said scanner output signal between said first and second signals;

second storage means connected to the output of said scanner for storing a charge indicative of the maximum amplitude of said scanner output signal between said first and third signals; and

comparator means connected to said first and second storage means for comparing the amplitudes of the charges stored thereon.

2. The invention in accordance with claim 1 wherein said first and second signal generating means include a pair of wheel sensors spaced apart along a length of said first rail and said third signal generating means includes a third wheel sensor disposed along said first rail between said first and second sensors.

3. The invention in accordance with claim 1 wherein said first storage means includes a first capacitor and a first relay first set of contacts interposed between said capacitor and said heat scanner output, said first relay being operatively connected to said first and second signal generating means so as to close said first contacts when said first signal is generated and open said first contacts when said second signal is generated.

4. The invention in accordance with claim 3 wherein said second storage means includes a second capacitor and a second relay set of contacts interposed between said capacitor and said heat scanner output, said second relay being operatively connected to said first and third signal generating means so as to close said second relay contacts when said first signal is generated and open said second relay contacts when said third signal is generated.

5. The invention in accordance with claim 4 wherein said comparator means includes:

a first resistor connected to said first capacitor, a second resistor connected to said second capacitor and to said first resistor, the values of said first and second resistors being in the inverse ratio of the expected value of the charges on said first and second capacitors for a particular form of bearing, and means connected to the junction of said resistors for determining if the charges on said capacitor are in said ratio.

6. The invention in accordance with claim 5 further comprising:

a first inverting amplifier interposed between said scanner and said first capacitor, a unity-gain inverting amplifier interposed between said first inverting amplifier and said second capacitor and said determining means includes a comparator having a positive input connected to the junction of said resistors and a negative input being connected to ground whereby said comparator produces an output signal only if the ratio of the charges on said first and second capacitors is substantially equal to the inverse ratio of the resistance of said first and second resistors.

7. The invention in accordance with claim 6 further comprising a second set of contacts of said first relay interposed between said first capacitor and said first resistor and a third set of contacts of said first relay interposed between said second capacitor and said second resistor.

8. The invention in accordance with claim 6 further comprising second comparator means for comparing the output of said unity-gain amplifier to a predetermined threshold level and for generating a first gate input signal in response to outputs of said unity-gain amplifier above said threshold, gate means having one input connected to the output of said second comparator and one input connected to the output of said comparator whereby said gate means produces an output signal only if both said comparators produce output signals.

9. The invention in accordance with claim 8 further comprising an identical circuit associated with the second raIl of said track, the output of the gate means of both of said circuits each forming an input to an additional gate, whereby said additional gate produces an output only if identical conditions exist on said first and second rails.

10. The invention in accordance with claim 5 wherein the ratio of said first resistor to said second resistor is 1:

1.2, said ratio being indicative of a roller bearing on said rail as distinct from a friction bearing.