# US 2014/0190290 A1 · Method and system for tensioning park brake cables > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0190290 A1 - Document ID: US20140190290A1 - Status: Published application - Kind: A1 - Application number: 13/736,186 - Filed: 2013-01-08 - Published: 2014-07-10 - Earliest claimed: 2013-01-08 - Assignees: GM Global Technology Operations LLC - Applicants: GM Global Technology Operations LLC - Inventors: Raymond J. Sapienza; Robbie D. Cannon - Web page: https://patentgrep.com/patent/US20140190290A1 ## CPC - F16C 1/22: Adjusting; Compensating length - B60T 7/107: {with electrical power assistance} - B60T 7/108: {with mechanisms to take up slack in the linkage to the brakes} - B60T 11/046: {Using cables (B60T11/043 takes precedence)} - F16D 65/46: with screw-thread and nut - B29C 65/485: {Multi-component adhesives, i.e. chemically curing as a result of the mixing of said multi-components} - B29C 66/9221: {by measuring the pressure, the force or the mechanical power} - B29C 66/959: {characterised by specific values or ranges of said specific variables} - F16C 1/223: {by adjusting the effective length of the flexible member} - F16C 2231/00: Running-in; Initial operation - F16D 2125/40: Screw-and-nut - Y10T 74/18576: including screw and nut - Y10T 74/20462: Specific cable connector or guide - F16C: SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS - B60T: VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL (electrodynamic brake systems for vehicle, in general B60L; brakes per se, i.e. devices where braking effect occurs, including ultimate brake actuators, F16D); ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES - F16D: COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES - B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00) - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract A method of tensioning a park brake system of a vehicle includes providing an adjustment mechanism having a nut in threaded engagement with a rod that defines a signal to noise ratio therebetween. The nut is advanced on the rod to remove slack until torque applied to the nut indicates that the park cables include a tension equal to an offset tension level. The nut is then retracted on the rod to introduce slack into the park cables and reduce the tension in the park cables to a target slack tension level. A signal to noise ratio between the nut and the rod is improved so that the cable tension may be predicted by the torque required to turn the nut on the rod, thereby allowing a torque indicating tool to measure the tension in the park cables my measuring the torque required to turn the nut on the rod. ## Claims ### Claim 1 A method of tensioning a park brake system of a vehicle, the method comprising: providing an adjustment mechanism having a threaded nut in threaded engagement with a threaded rod, wherein the threaded nut and the threaded rod define a signal to noise ratio therebetween that allows tension measurement of a plurality of park cables based upon a torque applied to the threaded nut; measuring torque applied to the threaded nut, while advancing the threaded nut on the threaded rod to remove slack and tighten the plurality of park cables, with a torque indicating tool until the measured torque indicates that the plurality of park cables include a tension equal to an offset tension level; and retracting the threaded nut on the threaded rod to introduce slack into the park cables and reduce the tension in the park cables to a target tension level. ### Claim 2 (depends on 1) A method as set forth in claim 1 wherein the signal to noise ratio between the threaded nut and the threaded rod is calculated by the Nominal-The-Best Type 1 method and is defined by the equation: S / N ≅ 10   Log  ( y _ 2 σ n - 1 2 ) wherein S/N is the signal to noise ratio, y is the mean of a plurality of cable tension values for a given torque input; and σn-1 is the standard deviation of the plurality of cable tension values for the given torque input. ### Claim 3 (depends on 2) A method as set forth in claim 2 wherein the signal to noise ratio is equal to or greater than 25 db with a standard deviation equal to or less than 75 Newtons. ### Claim 4 (depends on 1) A method as set forth in claim 1 wherein retracting the threaded nut on the threaded rod is further defined as retracting the coarse threaded nut on the threaded rod a pre-determined adjustment distance along a longitudinal axis of the threaded rod, wherein the pre-determined adjustment distance is related to a current position of an actuation lever of the park brake system. ### Claim 5 (depends on 4) A method as set forth in claim 4 further comprising determining the current position of the actuation lever. ### Claim 6 (depends on 5) A method as set forth in claim 5 further comprising identifying the appropriate pre-determined adjustment distance for the determined current position of the actuation lever required to introduce the desired amount of slack into the plurality of park cables for the current position of the actuation lever. ### Claim 7 (depends on 4) A method as set forth in claim 4 further comprising securing the threaded nut relative to the threaded rod after the threaded nut is retracted the pre-determined adjustment distance on the threaded rod. ### Claim 8 (depends on 7) A method as set forth in claim 7 wherein securing the threaded nut relative to the threaded rod includes adhering the threaded nut onto the threaded rod. ### Claim 9 (depends on 8) A method as set forth in claim 8 wherein adhering the threaded nut onto the threaded rod includes applying an adhesive to the threads of at least one of the threaded nut and the threaded rod prior to advancing the threaded nut on the threaded rod. ### Claim 10 (depends on 9) A method as set forth in claim 9 wherein applying the adhesive to the threads of at least one of the threaded nut and the threaded rod includes applying a first component of a two part epoxy adhesive to one of the threaded nut and the threaded rod, and applying a second component of the two part epoxy adhesive to the other of the threaded nut and the threaded rod. ### Claim 11 (depends on 10) A method as set forth in claim 10 further comprising curing the two part epoxy adhesive after the threaded nut is retracted the pre-determined adjustment distance on the threaded rod. ### Claim 12 (depends on 7) A method as set forth in claim 7 wherein securing the threaded nut relative to the threaded rod includes tightening a jam nut against the threaded nut tot lock the position of the threaded nut relative to the threaded rod. ### Claim 13 (depends on 1) A method as set forth in claim 1 wherein providing the adjustment mechanism having the threaded nut in threaded engagement with the threaded rod includes providing a lubricant between the threaded nut and the threaded rod to reduce friction between the threaded nut and the threaded rod to lower the signal to noise ratio therebetween. ### Claim 14 (depends on 1) A method as set forth in claim 1 wherein providing the adjustment mechanism having the threaded nut in threaded engagement with the threaded rod includes providing a course threaded nut and a course threaded rod including a thread form configured to require at least five Newton meters (5 NM) of torque to advance the threaded nut along the threaded rod. ### Claim 15 (depends on 14) A method as set forth in claim 14 wherein providing the adjustment mechanism having the threaded nut in threaded engagement with the threaded rod includes providing the course threaded nut and the course threaded rod including a thread form defining a pitch greater than two millimeters (2 mm). ### Claim 16 A park cable system for a vehicle, the park cable system comprising: an actuation lever; a first cable having a first end and a second end; and an adjustment mechanism interconnecting the actuation lever and the first cable, wherein the adjustment mechanism includes: an adjustment nut coupled to the actuation lever; and a rod coupled to the first end of the first cable and disposed in threaded engagement with the adjustment nut; wherein advancing the adjustment nut on the rod decreases a length between the actuation lever and the second end of the first cable to increase a tension of the first cable, and wherein retracting the adjustment nut on the rod increases the length between the actuation lever and the second end of the first cable to decrease the tension of the first cable; wherein the adjustment nut and the rod include a course thread form as defined under the Unified Thread Standard, such that advancing the adjustment nut along the rod defines a signal to noise ratio therebetween, as calculated by the Nominal-The-Best Type 1 method, that is equal to or greater than 25 dB with a standard deviation equal to or less than 75 Newtons, and allows tension measurement of the first cable based upon a torque applied to the adjustment nut, the signal to noise ratio being defined by the equation: S / N ≅ 10   Log  ( y _ 2 σ n - 1 2 ) wherein S/N is the signal to noise ratio, y is the mean of a plurality of cable tension values for a given torque input; and σn-1 is the standard deviation of the plurality of cable tension values for the given torque input. ### Claim 17 (depends on 16) A park cable system as set forth in claim 16 wherein the thread form of the adjustment nut and the rod is configured to require at least five Newton meters (5 NM) of torque to advance the adjustment nut along the rod. ### Claim 18 (depends on 16) A park cable system as set forth in claim 16 wherein the thread form of the adjustment nut and the rod includes a pitch greater than two millimeters (2 mm). ### Claim 19 (depends on 16) A park cable system as set forth in claim 16 further comprising a securing mechanism for securing a position of the adjustment nut relative to the rod. ### Claim 20 (depends on 19) A park cable system as set forth in claim 19 wherein the securing mechanism includes a two part epoxy adhesive bonding the adjustment nut to the rod.