# US 7,407,042 B2 · Brake actuator mechanism with overload protection > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,407,042 B2 - Document ID: US7407042B2 - Status: Granted - Kind: B2 - Application number: 11/056,958 - Filed: 2005-02-11 - Published: 2006-08-17 - Granted: 2008-08-05 - Earliest claimed: 2005-02-11 - Assignees: Bendix Spicer Foundation Brake LLC - Inventors: Daniel E. Banks; Michael R. Brown, II; Alan Hendershot - Web page: https://patentgrep.com/patent/US7407042B2 ## CPC - F16D 43/211: {with radially applied torque-limiting friction surfaces} - F16D 1/0835: {due to the elasticity of the ring or sleeve} - F16D 7/021: {with radially applied torque-limiting friction surfaces (F16D7/022 takes precedence)} - F16D 2121/14: Mechanical - F16D 2127/06: Locking mechanisms, e.g. acting on actuators, on release mechanisms or on force transmission mechanisms - F16D: COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES ## Abstract A brake actuator mechanism has an inner shaft received at least partially within an outer shaft. The overload protection device is disposed between the inner shaft and the outer shaft. The device selectively couples the inner shaft and the outer shaft so that when the outer shaft receives a torque beyond a predetermined limit, the device allows the outer shaft to rotate about the inner shaft without rotating the inner shaft. ## Claims ### Claim 1 A brake actuator mechanism, comprising: an inner shaft having a first portion connected to a clutch mechanism and a second portion distally opposite said first portion and having a first circumferential ring; an outer shaft overlapping at least a portion of said second portion of said inner shaft, said outer shaft terminating at said first circumferential ring of said inner shaft so that said outer shaft does not overlap said clutch mechanism; a second ring disposed between said inner shaft and said outer shaft, said second ring having at least one raised surface for selectively coupling said inner shaft and said outer shaft; wherein said second ring is compressed between said inner shaft and said outer shaft and couples said inner shaft and said outer shaft via a frictional engagement to a pre-determined torsional limit, and beyond said pre-determined torsional limit said second ring allows said outer shaft to rotate with respect to inner shaft. ### Claim 2 (depends on 1) The mechanism of claim 1, wherein said outer shaft, said inner shaft and said second ring are housed within a caliper housing. ### Claim 3 (depends on 2) The mechanism of claim 2, wherein a retaining ring is located within a groove in said caliper housing to secure said outer shaft within said caliper housing. ### Claim 4 (depends on 1) The mechanism of claim 1, wherein said outer shaft has a circumferential groove in an outer surface thereof, said groove receiving a seal therein. ### Claim 5 (depends on 1) The mechanism of claim 1, wherein said second ring is constructed of a flexible material. ### Claim 6 (depends on 1) The mechanism of claim 1, wherein said outer shaft has a recess for receiving said second portion of said inner shaft therein. ### Claim 7 (depends on 6) The mechanism of claim 6, wherein said recess has a substantially constant inner diameter and said second portion of said inner shaft has a substantially constant outer diameter. ### Claim 8 (depends on 1) The mechanism of claim 1, wherein said second ring is located about said second portion of said inner shaft. ### Claim 9 (depends on 1) The mechanism of claim 1, wherein said second ring has an inner surface and an outer surface. ### Claim 10 (depends on 9) The mechanism of claim 9, wherein said raised surface is on said outer surface of said second ring. ### Claim 11 (depends on 10) The mechanism of claim 10, wherein said raised surface on said outer surface is a series of ridges that alternate with a series of valleys. ### Claim 12 (depends on 11) The mechanism of claim 11, wherein said ridges and said valleys of said outer surface are bounded by two bands, wherein said ridges contact said outer shaft and said valleys contact said inner shaft. ### Claim 13 (depends on 12) The mechanism of claim 12, wherein said ridges exert a normal force on said outer shaft and said valleys exert a normal force on said inner shaft. ### Claim 14 A brake actuator mechanism, comprising: an inner shaft having a first portion connected to a clutch mechanism and a second portion distally opposite said first portion and having a radially extending first circumferential ring unitary with said inner shaft; an outer shaft having a recess for receiving said second portion of said inner shaft, said recess being located opposite said clutch mechanism so that said outer shaft does not overlap said clutch mechanism, wherein a gap is formed between said recess and said second portion of said inner shaft; and a second ring located in said gap and about said inner shaft, said second ring having a portion in contact with said recess and a portion in contact with said second portion of said inner shaft, wherein said second ring selectively couples said inner shaft and said outer shaft; wherein said second ring is compressed between said inner shaft and said outer shaft and couples said inner shaft and said outer shaft via a frictional engagement to a pre-determined torsional limit, and beyond said pre-determined torsional limit said second ring allows said outer shaft to rotate with respect to inner shaft. ### Claim 15 A method for selectively coupling a brake actuator mechanism, comprising: providing an outer shaft having a recess; locating an inner shaft within said recess until a first circumferential ring formed from said inner shaft and fixed about said inner shaft abuts an inner end portion of said outer shaft to prevent axial movement of said outer shaft with respect to said inner shaft and so that said outer shaft does not overlap a clutch mechanism, wherein a gap is formed between said recess and said inner shaft; and selectively coupling said inner shaft and said outer shaft with a second ring located in said gap, said second ring exerting a predetermined force on both said inner shaft and said outer shaft; wherein said second ring is compressed between said inner shaft and said outer shaft and couples said inner shaft and said outer shaft via a frictional engagement to a pre-determined torsional limit, and beyond said pre-determined torsional limit said second ring allows said outer shaft to rotate with respect to inner shaft. ### Claim 16 (depends on 15) The method of claim 15, wherein said second ring prevents torsional damage to a clutch mechanism by allowing said inner shaft to rotate with respect to said outer shaft when said outer shaft receives a torque beyond a pre-determined limit. ### Claim 17 (depends on 15) The method of claim 15, wherein said second ring has a plurality of ridges and a plurality of valleys and compression of said second ring causes said valleys to deflect and frictionally engage said inner shaft. ### Claim 18 (depends on 17) The method of claim 17, wherein said second ring has an outer surface with a plurality of ridges that frictionally engage with said outer shaft.