# US 2014/0196602 A1 · Anti-rotate attenuation device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0196602 A1 - Document ID: US20140196602A1 - Status: Published application - Kind: A1 - Application number: 13/743,725 - Filed: 2013-01-17 - Published: 2014-07-17 - Earliest claimed: 2013-01-17 - Assignees: GM Global Technology Operations LLC - Applicants: GM Global Technology Operations LLC - Inventors: Eric Thomas Carlson; Jack M. Gayney - Web page: https://patentgrep.com/patent/US20140196602A1 ## CPC - F16D 25/083: {Actuators therefor (F16D25/085 - F16D25/087 take precedence)} - F16J 1/00: Pistons; Trunk pistons; Plungers (bellows pistons F16J3/06; piston-rings or seats therefor F16J9/00; {manufacture of pistons B23P15/10}; rotary pistons, e.g. for "Wankel" type engines F01C; specific for combustion engines, i.e. constructed to withstand high temperature or modified for guiding, igniting, vaporising or otherwise treating the charge F02F; {pistons for hydraulic engines F03C}; pumps F04B; floats F16K33/00) - F16H 63/00: Control outputs {from the control unit} to change-speed- or reversing-gearings for conveying rotary motion {or to other devices than the final output mechanism} - F16H 63/3023: {the final output mechanisms comprising elements moved by fluid pressure (band brake actuating mechanisms F16H63/3003)} - F16H 2059/6807: {Status of gear-change operation, e.g. clutch fully engaged} - F16D: COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES - F16J: PISTONS {(specially adapted for dampers F16F9/32)}; CYLINDERS; SEALINGS - F16H: GEARING ## Abstract A piston assembly, which may be part of a concentric slave cylinder for use in an automatic transmission, is provided. The piston assembly includes a piston and a piston cylinder disposed adjacent to the piston and having portions forming a receiving slot. A piston guide is attached to the piston. The piston guide has a main body portion and an alignment protrusion extending from the main body portion. The alignment protrusion is disposed in the receiving slot of the piston cylinder. The alignment protrusion includes a main alignment portion and a spring lever. The spring lever is separated from the main alignment portion by a gap. Compressible material is disposed in the gap. ## Claims ### Claim 1 A piston assembly for use in an automatic transmission, the piston assembly comprising: a piston; a piston cylinder disposed adjacent to the piston and having portions forming a receiving slot; and a piston guide having a main body portion and an alignment protrusion extending from the main body portion, the piston guide being attached to the piston, the alignment protrusion being disposed in the receiving slot of the piston cylinder, the alignment protrusion comprising a main alignment portion and a spring lever, the spring lever being separated from the main alignment portion by a gap, the piston guide having a compressible material disposed in the gap. ### Claim 2 (depends on 1) The piston assembly of claim 1, wherein the compressible material is an elastomeric material. ### Claim 3 (depends on 2) The piston assembly of claim 2, wherein the main body portion of the piston guide is attached to the piston. ### Claim 4 (depends on 3) The piston assembly of claim 3, wherein the main body portion of the piston guide has a generally annular shape. ### Claim 5 (depends on 4) The piston assembly of claim 4, wherein the alignment protrusion has an arcuate shape. ### Claim 6 (depends on 5) The piston assembly of claim 5, wherein the piston is annular and the piston cylinder is annular. ### Claim 7 (depends on 6) The piston assembly of claim 6, wherein the piston cylinder is concentrically disposed within the piston. ### Claim 8 (depends on 7) The piston assembly of claim 7, wherein the piston guide comprises a polyamide-imide material. ### Claim 9 (depends on 8) The piston assembly of claim 8, wherein piston guide further comprises a tab extending from the main body portion, the tab being attached to the piston. ### Claim 10 (depends on 9) The piston assembly of claim 9, wherein the tab is splined to the piston. ### Claim 11 A concentric slave cylinder piston assembly for use in an automatic transmission, the assembly comprising: an inner piston; an inner piston cylinder disposed adjacent to the inner piston and having portions forming a receiving slot; an outer piston cylinder disposed adjacent to the inner piston; an outer piston disposed adjacent to the outer piston cylinder; and a piston guide having a main body portion and an alignment protrusion extending from the main body portion, the piston guide being attached to the inner piston, the alignment protrusion being disposed in the receiving slot of the inner piston cylinder, the alignment protrusion comprising a main alignment portion and a spring lever, the spring lever being separated from the main alignment portion by a gap, the piston guide having a compressible material disposed in the gap. ### Claim 12 (depends on 11) The assembly of claim 11, wherein the compressible material is an elastomeric material. ### Claim 13 (depends on 12) The assembly of claim 12, wherein the main body portion of the piston guide is attached to the inner piston. ### Claim 14 (depends on 13) The assembly of claim 13, wherein the main body portion of the piston guide has a generally annular shape. ### Claim 15 (depends on 14) The assembly of claim 14, wherein the alignment protrusion has an arcuate shape. ### Claim 16 (depends on 15) The assembly of claim 15, wherein each of the inner piston, the outer piston, the inner piston cylinder, and the outer piston cylinder is annular in shape. ### Claim 17 (depends on 16) The assembly of claim 16, wherein the inner piston cylinder is concentrically disposed within the inner piston, the inner piston is concentrically disposed within the outer piston cylinder, and the outer piston cylinder is concentrically disposed within the outer piston. ### Claim 18 (depends on 17) The assembly of claim 17, wherein the piston guide comprises a polyamide-imide material. ### Claim 19 (depends on 18) The assembly of claim 18, wherein piston guide further comprises a tab extending from the main body portion, the tab being splined to the inner piston. ### Claim 20 A concentric slave cylinder piston assembly for use in an automatic transmission, the assembly comprising: an annular inner piston; an annular inner piston cylinder disposed concentrically within the inner piston, the inner piston cylinder having portions forming a receiving slot; an annular outer piston cylinder disposed adjacent to the inner piston, wherein the inner piston is disposed concentrically within the outer piston cylinder; an annular outer piston disposed adjacent to the outer piston cylinder, wherein the outer piston cylinder is disposed concentrically within the outer piston; and a piston guide having an annular main body portion and an arcuate alignment protrusion extending from the main body portion, the main body portion being attached to the inner piston, the alignment protrusion being disposed in the receiving slot of the inner piston cylinder, the alignment protrusion comprising a main alignment portion and a spring lever, the spring lever being separated from the main alignment portion by a gap, the piston guide having a compressible elastomeric material disposed in the gap.