Railroad handbrake chain tension condition sensing device and method

A tension sensing device comprising:

• (a) a sensor mounted in a stationary position;
• (b) a member mounted for a reciprocal movement in a substantially linear direction relative to said sensor, said member including each of a first portion having a rear surface disposed so as to face said sensor and an opposed front surface and a second portion having a proximal end thereof disposed on and secured to said rear surface of said first portion, said second portion extending outwardly from said rear surface generally perpendicular thereto;
• (c) a sensor target disposed on and secured to a distal end of said second portion;
• (d) a compressible resilient means mounted between said rear surface of said first portion and a portion of a stationary structure;
• (e) whereby attainment of a predetermined tension in a force-producing elongated member moves the force-producing elongated member from its original position in a direction towards said sensor and positions said sensor target in operative sensing alignment therewith;
• and
• (f) whereby absence of said predetermined tension in the force-producing elongated member causes said compressible resilient means to move the force-producing elongated member in an opposite direction back to said original position and removes said sensor target from said operative sensing alignment with said sensor.

In combination with a railroad handbrake having a housing and a force-producing chain extending from said housing for connection to railcar brake rigging, a device for sensing a tension attainment on said force-producing chain, said device comprising:

• (a) a sensor mounted in a stationary position adjacent a bottom end of said housing;
• (b) a member mounted for a reciprocal movement in a substantially linear direction relative to said sensor, said member including each of a first portion having a rear surface disposed so as to face said sensor and an opposed front surface and a second portion having a proximal end thereof disposed on and secured to said rear surface of said first portion, said second portion extending outwardly from said rear surface generally perpendicular thereto;
• (c) a sensor target disposed on and secured to a distal end of said second portion;
• (d) a compressible resilient means mounted in abutting engagement with at least said rear surface of said first portion;
• (e) whereby take-up of said force-producing chain during at least partial handbrake application moves said member from its original position in a direction towards said sensor and positions said sensor target in operative sensing alignment therewith;
• and
• (f) whereby let-up of said force-producing chain during handbrake release causes said compressible resilient means to move said member in an opposite direction back to said original positions and removes said sensor target from said operative sensing alignment with said sensor.

In combination with a railroad handbrake having a housing and a force-producing chain extending from said housing for connection to railcar brake rigging, a device for sensing a tension condition of said force-producing chain, said device comprising:

• (a) a generally hollow enclosure body secured in a stationary position to one bottom corner of said housing, said body having each of an open end, an abutment disposed on and secured to an inner surface of a chain-facing wall, a first aperture formed through a thickness of each of said chain-facing wall and said abutment and a second aperture formed through a pair of spaced apart opposed walls of said housing, said pair of opposed walls disposed generally perpendicular to said chain-facing wall, said second aperture disposed in general alignment with an aperture formed through said one bottom corner of said housing;
• (b) a cover member secured to said body in a position to close said open end thereof;
• (c) an elongated brace having a proximal end thereof disposed on and secured to an outer surface portion of said body and having a distal end thereof positioned for engagement with an opposed bottom corner of said housing, said distal end having an aperture formed through a thickness thereof and aligned with an aperture formed through said opposed bottom corner of said housing;
• (d) a lubricating liner having an outer surface thereof engaging a periphery of said first aperture;
• (e) an L-shaped bracket secured to an inner surface of one of said opposed walls of said body;
• (f) a sensor securely attached onto said L-shaped bracket generally transverse to a direction of said force-producing chain;
• (g) a unitary one-piece member mounted for a reciprocal movement in a substantially linear direction relative to said sensor, said member including:
• i. a first portion having a substantially flat rear surface disposed so as to face said sensor, an opposed substantially flat front surface, a top end and a bottom end,
• ii. a pair of projections, each of said pair of projections depending from a respective top or bottom end,
• iii. an elongated second portion having a proximal end thereof disposed generally centrally on and secured to said rear surface, said second portion extending outwardly from said rear surface generally perpendicular thereto, said second portion having a peripheral surface thereof disposed in a generally abutting engagement with an inner surface of said lubricating liner, and
• iv. a threaded bore axially disposed in a distal end of said elongated second portion;
• (h) a sensor target having each of a magnetic head and a threaded stem axially extending therefrom, said threaded stem operatively engaging said threaded bore of said elongated second portion;
• (i) a compressible resilient elastomer caged between said rear surface of said first portion of said member and an outer surface of said chain facing wall of said body, said compressible resilient elastomer having a center aperture axially formed therethrough, said center aperture is sized so as to pass said elongated second portion of said member therethrough;
• (j) a unitary one-piece chain guide manufactured from a self-lubricating material and including:
• i. a chain engaging surface having each of a convex shape in a generally vertical plane and a concave shape in a generally horizontal plane when said device is installed for sensing said tension condition of said force-producing chain;
• ii. an opposed surface shaped and sized so as to abuttingly engage said front surface of said first portion of said member,
• iii. a pair of mounting flanges spaced apart in said generally vertical plane and extending from said opposed surface of said chain guide, and
• iv. a pair of apertures, each of said pair of apertures formed through a thickness of a respective mounting flange and operatively receiving therewithin a respective one of said pair of projections of said first portion of said member;
• (k) a connector operatively connecting said sensor to a control system;
• (l) whereby take-up of said force-producing chain during at least partial handbrake application attains a predetermined tension thereon and moves said member from its original position in a direction towards said sensor and positions said sensor target in operative sensing alignment therewith;
• (m) whereby let-up of said force-producing chain during handbrake release causes said compressible resilient elastomer to move said member in an opposite direction back to said original positions and remove said sensor target from said operative sensing alignment with said sensor;
• and
• (n) whereby said sensor generates a control signal in response to sensing or not sensing said sensor target.

A method for sensing at least partial tension attainment on a force-producing chain of a railroad handbrake, said method comprising the steps of:

• (a) mounting a member for each of an engagement with said force-producing chain of said railroad handbrake and a reciprocal movement in a generally horizontal linear direction;
• (b) mounting a sensor in proximity to a bottom end of a housing of said railroad handbrake in a position to sense said generally linear movement of said member;
• (c) moving said member in said generally horizontal linear direction;
• and
• (d) sensing, with said sensor mounted in step (b), said generally horizontal linear movement of said member, mounted in step (a) during one of at least partial handbrake application and handbrake release.

In a combination with a railroad handbrake having a housing and a force-producing chain extending from said housing for connection to railcar brake rigging, a device for sensing a tension condition in said force-producing chain, said device comprising:

• (a) a member mounted adjacent to a bottom end of said housing for a substantially linear movement during handbrake application and release;
• (b) a sensor mounted in a stationary position;
• (c) a sensor target disposed on and secured to an end of said member, said sensor target being selectively positioned in an operative alignment with said sensor during said substantially linear movement of said member;
• (d) a compressible resilient means mounted between a portion of said member and a portion of a stationary structure;
• (e) whereby attainment of a predetermined tension on said force-producing chain moves said member from its original position in a direction towards said sensor and positions said sensor target in operative sensing alignment therewith;
• and
• (f) whereby absence of said predetermined tension on said force-producing chain causes said compressible resilient means to move said member in an opposite direction back to said original position and removes said sensor target from said operative sensing alignment with said sensor.