# US 2014/0360292 A1 · Reciprocating piston mechanism > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0360292 A1 - Document ID: US20140360292A1 - Status: Published application - Kind: A1 - Application number: 14/373,470 - Filed: 2013-01-24 - Published: 2014-12-11 - Earliest claimed: 2012-01-24 - Assignees: Gomecsys B.V. - Inventors: Lambertus Hendrik De Gooijer - Web page: https://patentgrep.com/patent/US20140360292A1 ## CPC - F16H 37/124: {for interconverting rotary motion and reciprocating motion} - F02B 75/048: {by means of a variable crank stroke length} - F16H 21/22: with one connecting-rod and one guided slide to each crank or eccentric - F02B 41/04: in main cylinders - Y10T 74/18208: Crank, pitman, and slide - F16H: GEARING - F02B: INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL (gas-turbine plants F02C; hot-gas or combustion-product positive-displacement engine plants F02G) - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract A reciprocating piston mechanism comprises a crankcase and a crankshaft. The crankshaft is supported by the crankcase and rotatable with respect thereto about a crankshaft axis. The mechanism further comprises at least a connecting rod including a big end and a small end, a piston which is rotatably connected to the small end, and a crank member which is rotatably mounted on the crankpin. The crank member comprises at least a bearing portion and has an outer circumferential wall which bears the big end of the rod such that the rod is rotatably mounted on the bearing portion of the crank member via the big end. The crank member is provided with a crank member gear. The crank member gear meshes with at least an intermediate gear, which also meshes with an auxiliary gear. The auxiliary gear is fixed to an auxiliary shaft that extends concentrically through the crankshaft. ## Claims ### Claim 1 A reciprocating piston mechanism comprising a crankcase; a crankshaft having at least a crankpin, said crankshaft being supported by the crankcase and rotatable with respect thereto about a crankshaft axis; at least a connecting rod including a big end and a small end; a piston being rotatably connected to the small end; a crank member being rotatably mounted on the crankpin, and comprising at least a bearing portion having an outer circumferential wall which bears the big end of the connecting rod such that the connecting rod is rotatably mounted on the bearing portion of the crank member via the big end; wherein the crank member is provided with a crank member gear, being an external gear, which meshes with at least an intermediate gear, being an external gear, which intermediate gear also meshes with an auxiliary gear being an external gear, wherein the auxiliary gear is fixed to an auxiliary shaft which extends concentrically through the crankshaft, wherein the crankshaft and the auxiliary shaft are rotatable with respect to each other. ### Claim 2 (depends on 1) The reciprocating piston mechanism according to claim 1, wherein the gear ratio between the crank member gear and the auxiliary gear is two. ### Claim 3 (depends on 1) The reciprocating piston mechanism according to claim 1, wherein the bearing portion is eccentrically disposed with respect to the crankpin. ### Claim 4 (depends on 1) The reciprocating piston mechanism according to claim 1, wherein the crank member gear meshes with at least a further intermediate gear which also meshes with the auxiliary gear. ### Claim 5 (depends on 1) The reciprocating piston mechanism according to claim 1, wherein the mechanism is provided with a drive mechanism configured to turn the auxiliary gear with respect to the crankcase about the crankshaft axis. ### Claim 6 (depends on 5) The reciprocating piston mechanism according to claim 5, wherein the drive mechanism comprises a stop block, which is configured to fix the auxiliary shaft at different angular positions with respect to the crankcase. ### Claim 7 (depends on 6) The reciprocating piston mechanism according to claim 6, wherein the stop block comprises a control ring which is fixed to the auxiliary shaft and provided with a plurality of recesses, and an actuator including a controlled displaceable pin that fits in each of the respective recesses. ### Claim 8 (depends on 6) The reciprocating piston mechanism according to claim 6, wherein the stop block comprises a control ring which is fixed to the auxiliary shaft in rotational direction thereof, and wherein an electromagnet is present for fixing the control ring to the crank case. ### Claim 9 (depends on 5) The reciprocating piston mechanism according to claim 5, wherein the drive mechanism comprises a drivable worm configured to mesh with a worm gear which is fixed to the auxiliary shaft. ### Claim 10 (depends on 1) The reciprocating piston mechanism according to claim 1, wherein the intermediate gear extends beyond the crank member gear in at least one longitudinal direction thereof, wherein the auxiliary gear meshes with the intermediate gear such that the auxiliary gear partly overlaps the crank member gear. ### Claim 11 A reciprocating piston mechanism comprising a crankcase; a crankshaft having at least a crankpin, said crankshaft being supported by the crankcase and rotatable with respect thereto about a crankshaft axis; at least a connecting rod including a big end and a small end; a piston being rotatably connected to the small end; a crank member being rotatably mounted on the crankpin, and comprising at least a bearing portion having an outer circumferential wall which bears the big end of the connecting rod such that the connecting rod is rotatably mounted on the bearing portion of the crank member via the big end; wherein the crank member is driveably coupled to an auxiliary wheel which is fixed to an auxiliary shaft that extends concentrically through the crankshaft, wherein the crankshaft and the auxiliary shaft are rotatable with respect to each other, wherein the auxiliary wheel is disposed at the same side of an adjacent crank arm as the crank member, wherein the mechanism is configured such that under operating conditions the crank member rotates in the same direction as the crankshaft and at half speed thereof, whereas the auxiliary shaft has a substantially fixed angular position with respect to the crankcase. ### Claim 12 (depends on 11) The reciprocating piston mechanism according to claim 11, wherein the crank member comprises a crank member wheel which is driveably coupled to the auxiliary wheel by a toothed belt. ### Claim 13 (depends on 11) The reciprocating piston mechanism according to claim 11, wherein the crank member comprises a crank member sprocket and the auxiliary wheel is formed by an auxiliary sprocket, wherein the crank member sprocket is drivable by a chain. ### Claim 14 (depends on 11) The reciprocating piston mechanism according to claim 11, wherein the crank member is provided with a crank member gear, and the auxiliary wheel is formed by an auxiliary gear being an external gear, wherein the crank member gear and the auxiliary gear are driveably coupled to each other by at least an intermediate gear, being an external gear, which meshes with the auxiliary gear and the crank member gear. ### Claim 15 (depends on 5) The reciprocating piston mechanism according to claim 5, wherein the drive mechanism is provided with a spring that is fixed to the auxiliary shaft and the crankcase. ### Claim 16 (depends on 1) The reciprocating piston mechanism according to claim 1, wherein the internal diameter of the crank member is enlarged at an end portion thereof. ### Claim 17 (depends on 1) The reciprocating piston mechanism according to claim 1, wherein the crank member comprises a second crank member gear configured to drive at least a further crank member including a further crank member gear, which further crank member is rotatable mounted to a further crankpin, wherein the crank member gear and the second crank member gear are located at opposite end portions of the crank member, wherein the second crank member gear meshes with a further auxiliary gear which is fixed to a shaft that extends through an adjacent crank arm and on which shaft another auxiliary gear is fixed which meshes with the further crank member gear, wherein the diameter of the crankpin at the crank member gear is smaller than the diameter of the further crankpin at the further crank member gear. ### Claim 18 (depends on 1) The reciprocating piston mechanism according to claim 1, wherein the crank member comprises a second crank member gear for configured to drive at least a further crank member including a further crank member gear, which further crank member is rotatable mounted to a further crankpin, wherein the crank member gear and the second crank member gear are located at opposite end portions of the crank member, wherein the second crank member gear meshes with a further auxiliary gear which is fixed to a shaft that extends through an adjacent crank arm and on which shaft another auxiliary gear is fixed which meshes with the further crank member gear, wherein the diameter of the crank member gear is smaller than the diameter of the second crank member gear and/or wherein the width of the crank member gear is smaller than the width of the second crank member gear. ### Claim 19 (depends on 1) The reciprocating piston mechanism according to claim 1, wherein the crankpin is mounted to an adjacent crank arm by means of a press fit, wherein the length of the press fit in axial direction of the crankpin is larger than 30% of the diameter of the crankpin. ### Claim 20 (depends on 19) The reciprocating piston mechanism according to claim 19 the length of the press fit in axial direction of the crankpin is larger than 40% of the diameter of the crankpin. ### Claim 21 (depends on 7) The reciprocating piston mechanism according to claim 7 and further comprising a spring that is fixed to the auxiliary shaft and the crankcase. ### Claim 22 (depends on 7) The reciprocating piston mechanism according to claim 7 and further comprising a spring that is fixed to the auxiliary shaft and the crankcase.