# US 6,296,208 B1 · Railway switch machine point detection system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 6,296,208 B1 - Document ID: US6296208B1 - Status: Granted - Kind: B1 - Application number: 09/382,439 - Filed: 1999-08-25 - Granted: 2001-10-02 - Earliest claimed: 1999-08-25 - Assignees: Union Switch & Signal Inc. - Inventors: Raymond C. Franke - Web page: https://patentgrep.com/patent/US6296208B1 ## CPC - B61L 5/107: {electrical control of points position} - B61L: GUIDING RAILWAY TRAFFIC; ENSURING THE SAFETY OF RAILWAY TRAFFIC (brakes or auxiliary equipment B61H, B61K; point or crossing construction E01B) ## Abstract A point detection system for a railway switch machine having a housing includes a point detector bar positionable in a normal point position and a reverse point position, and point detecting sensors positioned within the housing for detecting when the point detector bar is in the normal point position and when the point detector bar is in the reverse point position. The point detecting sensors may include a first proximity sensor for detecting when the point detector bar is in the normal point position and a second proximity sensor for detecting when the point detector bar is in the reverse point position. Preferably, the first proximity sensor and the second proximity sensor are inductive proximity sensors. A method of point detection for a railway switch machine is also provided. ## Claims ### Claim 1 A point detection system for a railway switch machine having a housing, said point detection system comprising: a point detector bar positionable in a normal point position and a reverse point position; a point detector target affixed to said point detector bar; point detecting means positioned within the housing for detecting when said point detector bar is in said normal point position and when said point detector bar is in said reverse point position, said point detecting means including a first proximity sensor for detecting said point detector target when said point detector bar is in said normal point position and a second proximity sensor for detecting said point detector target when said point detector bar is in said reverse point position, said first proximity sensor generating a normal point detection signal and said second proximity sensor generating a reverse point detection signal, said normal point detection signal having a first predetermined range of values to indicate that said point detector bar is in said normal point position and having a second predetermined range of values, which is different from said first predetermined range of values, to indicate that said point detector bar is not in said normal point position, said reverse point detection signal having a third predetermined range of values to indicate that said point detector bar is in said reverse point position and having a fourth predetermined range of values, which is different from said third predetermined range of values, to indicate that said point detector bar is not in said reverse point position; and means for processing point detection information from said normal point detection signal and said reverse point detection signal. ### Claim 2 (depends on 1) The point detection system of claim 1 wherein said first proximity sensor and said second proximity sensor are inductive proximity sensors. ### Claim 3 (depends on 1) The point detection system of claim 1 further including first point mounting means for mounting said first proximity sensor in slidable proximity to said point detector target such that said first proximity sensor is slidably adjustable relative to said point detector target; and second point mounting means for mounting said second proximity sensor in proximity to said point detector target such that said second proximity sensor is slidably adjustable relative to said point detector target. ### Claim 4 (depends on 1) The point detection system of claim 1 wherein said normal point detection signal is indeterminate of the position of said point detector bar when said normal point detection signal has a value which is less than said first predetermined range of values, greater than said first predetermined range of values but less than said second predetermined range of values, or greater than said second predetermined range of values. ### Claim 5 (depends on 1) The point detection system of claim 1 wherein said reverse point detection signal is indeterminate of the position of said point detector bar when said reverse point detection signal has a value which is less than said third predetermined range of values, greater than said third predetermined range of values but less than said fourth predetermined range of values, or greater than said fourth predetermined range of values. ### Claim 6 A point detection system for a railway switch machine having a housing defining a first side wall and an opposing second side wall, a point detector bar with a first and a second end positionable in a normal point position and a reverse point position, a slide bar positionable in a normal locked position and a reverse locked position, and means for indicating switching and locking data, wherein said point detection system comprises: a support sleeve, affixed within the housing to the first side wall and the opposing second side wall, for receiving and slidably supporting the first end of the point detector bar therewithin; means defined in the first side wall of the housing, through which the point detector bar is slidably retained by the first side wall, such that the first end of the point detector bar is slidably captivated within said support sleeve within the housing and the second end of the point detector bar is positioned outside of the housing; a point detector target integrally engaged with the first end of the point detector bar within the housing; and point detecting means positioned within the housing and coupled to the means for indicating switching and locking data for detecting said point detector target when the point detector bar is positioned in the normal point position and the reverse point position, wherein said point detecting means generates a normal point detection signal that is transmitted to the means for indicating switching and locking data when said point detecting means detects said point detector target with the point detector bar in the normal point position and said point detector means generates a reverse point detection signal that is transmitted to the means for indicating switching and locking data when said point detecting means detects said point detector target with the point detector bar in the reverse point position. ### Claim 7 (depends on 6) The point detection system of claim 6, further including a slot defined by said support sleeve, through which said point detector target is detectable by said point detecting means when said point detector bar is positioned within said support sleeve. ### Claim 8 (depends on 6) The point detection system of claim 6 wherein said point detecting means includes at least one proximity sensor and said point detector target comprises a metallic material. ### Claim 9 (depends on 6) The point detection system of claim 6 wherein said point detecting means includes a first proximity sensor for detecting said point detector target when said point detector bar is in said normal point position and a second proximity sensor for detecting said point detector target when said point detector bar is in said reverse point position. ### Claim 10 (depends on 9) The point detection system of claim 9 wherein said first proximity sensor and said second proximity sensor are inductive proximity sensors. ### Claim 11 (depends on 9) The point detection system of claim 9 further including first point mounting means for mounting said first proximity sensor in slidable proximity to said point detector target such that said first proximity sensor is slidably adjustable relative to said point detector target; and second point mounting means for mounting said second proximity sensor in proximity to said point detector target such that said second proximity sensor is slidably adjustable relative to said point detector target. ### Claim 12 (depends on 9) The point detection system of claim 9 wherein said first proximity sensor generates a normal point detection signal that is transmitted to the means for indicating switching and locking data and said second proximity sensor generates a reverse point detection signal that is transmitted to the means for indicating switching and locking data. ### Claim 13 (depends on 12) The point detection system of claim 12 wherein said normal point detection signal is in a first predetermined range to indicate that said point detector bar is in said normal point position and is in a second predetermined range to indicate that said point detector bar is not in said normal point position. ### Claim 14 (depends on 13) The point detection system of claim 13 wherein said normal point detection signal is indeterminate of the position of said point detector bar when said normal point detection signal is less than said first predetermined range, greater than said first predetermined range but less than said second predetermined range, or greater than said second predetermined range. ### Claim 15 (depends on 12) The point detection system of claim 12 wherein said reverse point detection signal is in a first predetermined range to indicate that said point detector bar is in said reverse point position and is in a second predetermined range to indicate that said point detector bar is not in said reverse point position. ### Claim 16 (depends on 15) The point detection system of claim 15 wherein said reverse point detection signal is indeterminate of the position of said point detector bar when said reverse point detection signal is less than said first predetermined range, greater than said first predetermined range but less than said second predetermined range, or greater than said second predetermined range. ### Claim 17 (depends on 6) The point detection system of claim 6, further including a slide bar target integrally engaged with the slide bar within the housing; and lock detecting means, coupled to the means for indicating switching and locking data, for detecting said slide bar target when the slide bar is positioned in the normal locked position and the reverse locked position, wherein said lock detecting means generates a normal locked detection signal and a reverse locked detection signal that is transmitted to the means for indicating switching and locking data when said slide bar target is detected in the normal locked position and the reverse locked position, respectively. ### Claim 18 (depends on 17) The point detection system of claim 17 wherein said lock detecting means includes a first proximity sensor for detecting said slide bar target when the slide bar is positioned in the normal locked position and a second proximity sensor for detecting said slide bar target when the slide bar is positioned in the reverse locked position. ### Claim 19 (depends on 18) The point detection system of claim 18 wherein said first proximity sensor and said second proximity sensor are inductive proximity sensors. ### Claim 20 (depends on 18) The point detection system of claim 18 further including first lock mounting means and second lock mounting means for mounting said first proximity sensor and said second proximity sensor, respectively, in slidable proximity to said slide bar target such that respective said first proximity sensor and said second proximity sensor are slidably adjustable relative to said slide bar target. ### Claim 21 (depends on 18) The point detection system of claim 18 wherein said first proximity sensor generates said normal locked detection signal that is transmitted to the means for indicating switching and locking data and said second proximity sensor generates said reverse locked detection signal that is transmitted to the means for indicating switching and locking data. ### Claim 22 (depends on 21) The point detection system of claim 21 wherein said normal locked detection signal is in a first predetermined range to indicate that said slide bar is in said normal locked position and a second predetermined range to indicate that said slide bar is not in said normal locked position. ### Claim 23 (depends on 22) The point detection system of claim 22 wherein said normal locked detection signal is indeterminate of the position of said slide bar when said normal locked detection signal is less than said first predetermined range, greater than said first predetermined range but less than said second predetermined range, or greater than said second predetermined range. ### Claim 24 (depends on 21) The point detection system of claim 21 wherein said reverse locked detection signal is in a first predetermined range to indicate that said slide bar is in said reverse locked position and a second predetermined range to indicate that said slide bar is not in said reverse locked position. ### Claim 25 (depends on 24) The point detection system of claim 24 wherein said reverse locked detection signal is indeterminate of the position of said slide bar when said reverse locked detection signal is less than said first predetermined range, greater than said first predetermined range but less than said second predetermined range, or greater than said second predetermined range.