# US 5,346,045 A · Electrically powered actuator > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,346,045 A - Document ID: US5346045A - Status: Granted - Kind: A - Application number: 08/001,343 - Filed: 1993-01-07 - Granted: 1994-09-13 - Earliest claimed: 1992-01-09 - Assignees: Link-Miles Limited - Inventors: George R. Bennett; Terence F. H. Faithfull - Web page: https://patentgrep.com/patent/US5346045A ## CPC - F16H 25/20: Screw mechanisms (with automatic reversal F16H25/12) - F16H 25/2015: {Means specially adapted for stopping actuators in the end position; Position sensing means} - G09B 9/12: Motion systems for aircraft simulators - F16H 2025/2081: {Parallel arrangement of drive motor to screw axis} - Y10T 74/18688: Limit stop - Y10T 74/18704: Means to selectively lock or retard screw or nut - F16H: GEARING - G09B: EDUCATIONAL OR DEMONSTRATION APPLIANCES; APPLIANCES FOR TEACHING, OR COMMUNICATING WITH, THE BLIND, DEAF OR MUTE; MODELS; PLANETARIA; GLOBES; MAPS; DIAGRAMS (devices for psychotechnics or for testing reaction times A61B5/16; games, sports, amusements A63; projectors, projector screens G03B) - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract A linear actuator has reversible electric motors driving a screw-threaded shaft engaging a roller nut. A tubular housing attached to the nut has at its remote end an internal seating member and load securing lugs. An hydraulic shock absorber unit, providing linear deceleration, is normally held in its most relaxed condition between the seating member and an end of a spacer tube butting against the nut. When the nut is within the shock absorber stroke distance of the driven end of the shaft, the free end of the shaft compresses the shock absorber unit against the seating. When the nut is within shock absorber stroke distance of the free end of the shaft, a ring engages a stop collar, thereby holding the shock absorber body at a fixed distance from the free end of the shaft, and the spacer tube compresses the shock absorber unit. A centrifugal brake is provided on a drive coupling pulley, and restrains rotation of the shaft above a predetermined rate. ## Claims ### Claim 1 An electrically powered actuator, comprising: a) bidirectional electrically powered drive member; b) a driven member coupled to the electrically powered drive member to be driven thereby; c) a travelling member engaged with the driven member and displaceable in opposite directions relative to the driven member between two limits of displacement d) a shock absorber unit disposed and coupled relative to the driven and travelling members to gradually slow down displacement of the travelling member relative to the driven member when the travelling member approaches each of said limits of displacement; said shock absorber unit including: 1) first and second parts that are movable relative to each other and relative to the driven and travelling members; 2) a limiter for limiting the extent of movement of said first and second parts relative to the driven member and relative to the travelling member, said limiter being coupled to the driven and travelling members such that the shock absorber unit is stressed by said limiter when the travelling member approaches each of said limits of displacement, said limiter including a first retainer for fixing a maximum distance of displacement between one of said driven and travelling members and said second part, and a second retainer for fixing a maximum distance of displacement between said second part and the other of the driven and travelling said members; and e) a centrifugal braking member for selectively restraining the driven member. ### Claim 2 An electrically powered actuator comprising: a) a bidirectional electrically powered drive member; b) a driven member comprising a screw-threaded shaft coupled to the electrically powered drive member to be driven by the drive member; c) a travelling member engaged with the driven member and displaceable in opposite directions relative to the driven member between two limits of displacement, the travelling member including: 1) a nut engaged with a thread of the screw-threaded shaft; 2) a tubular member fixedly engaged at one end thereof with the nut and having a fixed seating member located at the other end thereof, the tubular member containing the shock absorber unit which is disposed in the tubular member such that the shock absorber unit is compressed between one end of the shaft and the fixed seating member when the nut is within less than a predetermined distance from the other end of the shaft; d) a shock absorber unit disposed and coupled relative to the driven and travelling members to gradually slow down displacement of the travelling member relative to the driven member when the travelling member approaches each of said limits of displacement; and e) a centrifugal braking member for selectively restraining the driven member. ### Claim 3 An electrically powered actuator, comprising: a) a bidirectional electrically powered drive member; b) a driven member comprising a screw-threaded shaft coupled to the electrically powered drive member to be driven thereby; c) a travelling member comprising a roller nut engaged with a thread of the screw-threaded shaft of the driven member and displaceable in opposite directions relative to the driven member between two limits of displacement; d) a shock absorber unit disposed and coupled relative to the driven and travelling members to gradually slow down displacement of the travelling member relative to the driven member when the travelling member approaches each of said limits of displacement; and e) a centrifugal braking member for selectively restraining the driven member. ### Claim 4 An electrically powered actuator, comprising: a) bidirectional electrically powered drive member; b) a driven member coupled to the electrically powered drive member to be driven thereby, said driven member being rotated by the drive member; c) a travelling member engaged with the driven member and displaceable in opposite directions relative to the driven member between two limits of displacement; d) a shock absorber unit disposed and coupled relative to the driven and travelling members to gradually slow down displacement of the travelling member relative to the driven member when the travelling member approaches each of said limits of displacement; the shock absorber unit including: 1) first and second parts that are movable relative to each other and relative to the driven and travelling members; 2) a limiter for limiting the extent of movement of said first and second parts relative to the driven member and relative to the travelling member, said limiter being coupled to the driven and travelling members such that the shock absorber unit is stressed by said limiter when the travelling member approaches each of said limits of displacement, said limiter including a first retainer for fixing a maximum distance of displacement between one of said driven and travelling members and said second part and a second retainer for fixing a maximum distance of displacement between said second part and the other of said driven and travelling members; and e) a centrifugal braking member coupled to said driven member to restrain rotation of said driven member above a predetermined rate of rotation thereof. ### Claim 5 (depends on 4) An actuator according to claim 4, wherein the first retainer comprises a seating member attached to said one of said driven and travelling members, and the second retainer comprises a framework attached to said second part and held on said other of said driven and travelling members. ### Claim 6 (depends on 5) An actuator according to claim 5, wherein said driven and travelling members are elongate and said other of said driven and travelling members is coaxially disposed with said one of said driven and travelling members, and the shock absorber unit is disposed between said seating member and one end of said other of the driven and travelling members. ### Claim 7 (depends on 4) An actuator according to claim 4, wherein the driven member includes a screw-threaded shaft, and the travelling member includes a nut engaged with a thread of the shaft. ### Claim 8 (depends on 7) An actuator according to claim 7, wherein the travelling member includes a tubular member fixedly engaged at one end thereof with the nut and having a seating member fixed at one end thereof, the shock absorber unit being disposed in the tubular member so that the shock absorber unit is compressed between one end of the shaft and a fixed seating member when the nut is within less than a predetermined distance from the other end of the shaft. ### Claim 9 (depends on 8) An actuator according to claim 8, wherein first and second spacers are provided within the tubular member for fixing a minimum distance of separation between the nut and the shock absorber unit, and for fixing a maximum distance of separation between said one end of the shaft and the shock absorber, the arrangement of the first and second spacers being such that the shock absorber unit is compressed between the first and second spacers when the distance between the nut and said one end of the shaft is less than a predetermined amount. ### Claim 10 (depends on 9) An actuator according to claim 9, wherein the first spacer comprises an inner tubular member located within said tubular member of said travelling member and disposed between the nut and the shock absorber unit, and the second spacer comprises a spacing member attached to a body portion of the shock absorber unit and extending to a ring encircling the shaft and engageable with a stop member on said one end of the shaft. ### Claim 11 (depends on 7) An actuator according to claim 7, wherein the nut is a roller nut. ### Claim 12 (depends on 4) An actuator according to claim 4, wherein the centrifugal braking member includes at least one weight member pivotally attached to the driven member and spring loaded to hold a brake shoe away from an encircling member fixed to a housing of the drive member, the spring loading being such that centrifugal movement of the weight member during rotation of the driven member allows the shoe to frictionally engage a surface of the encircling member when the rate of rotation is above said predetermined rate. ### Claim 13 (depends on 4) An actuator according to claim 4, wherein the travelling member is engaged with the driven member for displacement of the travelling member relative to the driven member in the form of translation. ### Claim 14 (depends on 4) An actuator according to claim 4, wherein the shock absorber unit linearly decelerates the travelling member relative to the driven member when the travelling member approaches each of said limits of displacement. ### Claim 15 (depends on 4) An actuator according to claim 4, wherein a cut-off member is provided for cutting off a supply of electric power to the drive member when the travelling member approaches each of the limits of displacement. ### Claim 16 (depends on 4) An actuator according to claim 4, wherein the drive member includes a rotary member and the driven member is coupled directly to the rotary member to rotate therewith in operation. ### Claim 17 An electrically powered actuator, comprising: a) a bidirectional electrically powered drive member; b) a driven member coupled to the electrically powered drive member to be driven thereby, said driven member being rotated by the drive member; c) a travelling member engaged with the driven member and displaceable in opposite directions relative to the driven member between two limits of displacement; d) a shock absorber unit disposed and coupled relative to the driven and travelling members to gradually slow down displacement of the travelling member relative to the driven member when the travelling member approaches each of the limits of displacement; the shock absorber unit including: 1) first and second parts that are movable relative to each other and relative to the driven and travelling members; 2) a limiter for limiting the extent of movement of said first and second parts relative to the driven member and relative to the travelling member, said limiter being coupled to the driven and travelling members such that the shock absorber unit is stressed by said limiter when the travelling member approaches each of said limits of displacement, said limiter including a first retainer for fixing a maximum distance of displacement between one of said driven and travelling members and said second part and a second retainer for fixing a maximum distance of displacement between said second part and the other of said driven and travelling members, the first retainer comprising a seating member attached to said one of said driven and travelling members, the second retainer comprising a framework attached to said second part and held on said other Of said driven and travelling members, said driven and travelling members are elongate and said other of said driven and travelling members is coaxially disposed with said one of said driven and travelling members, and the shock absorber unit is disposed between said seating member and one end of said other of the driven and travelling members; and e) a centrifugal braking member coupled to the driven member to restrain rotation of the driven member above a predetermined rate of rotation thereof, said centrifugal braking member including at least one weight member pivotally attached to the driven member and spring loaded to hold a brake shoe away from an encircling member fixed to a housing of the drive member, the spring loading being such that centrifugal movement of the weight member during rotation of the driven member allows the shoe to frictionally engage a surface of the encircling member when the rate of rotation is above said predetermined rate. ### Claim 18 (depends on 17) An actuator according to claim 17, wherein the travelling member is engaged with the driven member for displacement of the travelling member relative to the driven member in the form of translation, the shock absorber unit linearly decelerates the travelling member relative to the driven member when the travelling member approaches each of said limits of displacement, a cut-off member is provided for cutting off a supply of electric power to the drive member when the travelling member approaches each of said limits of displacement, and the drive member includes a rotary member, the driven member being coupled directly to the rotary member to rotate therewith in operation. ### Claim 19 (depends on 17) An actuator according to claim 17, wherein the driven member includes a screw-threaded shaft, the travelling member includes a roller nut engaged with a thread of the screw-threaded shaft and a tubular member fixedly engaged at one end thereof with the nut and having a fixed seating member located at the other end thereof, the tubular member containing the shock absorber unit which is disposed in the tubular member such that the shock absorber unit is compressed between one end of the shaft and the fixed seating member when the nut is within less than a predetermined distance from the other end of the shaft, first and second spacers being provided within the tubular member for fixing a minimum distance of separation between the nut and the shock absorber unit and for fixing a maximum distance of separation between said one end of the shaft and the shock absorber unit, the arrangement of said first and second spacers being such that the shock absorber unit is compressed between the first and second spacers when the distance between the nut and said one end of the shaft is less than a predetermined amount, the first spacer comprises an inner tubular member located within said tubular member of said travelling member and disposed between the nut and the shock absorber unit, and the second spacer comprises a spacing member attached to a body portion of the shock absorber unit and extending to a ring encircling the shaft and engageable with a stop member on said one end of the shaft. ### Claim 20 An electrically powered actuator, comprising: a) a bidirectional electrically powered drive member; b) a driven member comprising a screw threaded shaft coupled to the electrically powered drive member to be driven thereby, said driven member being rotated by the drive member; c) a travelling member engaged with the driven member and displaceable in opposite directions relative to the driven member between two limits of displacement, the travelling member including: 1) a roller nut engaged with a thread of the screw-threaded shaft; 2) a tubular member fixedly engaged at one end thereof with the nut and having a fixed seating member located at the other end thereof, the tubular member containing the shock absorber unit which is disposed in the tubular member such that the shock absorber unit is compressed between one end of the shaft and the fixed seating member when the nut is within less than a predetermined distance from the other end of the shaft; 3) first and second spacers provided within the tubular member for fixing a minimum distance of separation between the nut and the shock absorber unit, and for fixing a maximum distance of separation between said one end of the shaft and the shock absorber, the arrangement of said first and second spacers being such that the shock absorber unit is compressed between the first and second spacers when the distance between the nut and said one end of the shaft is less than a predetermined amount, the first spacer comprises an inner tubular member located within said tubular member of said travelling member and disposed between the nut and the shock absorber unit, and the second spacer comprises a spacing member body portion of the shock absorber unit and extending to a ring encircling the shaft and engageable with a stop member on said one end of the shaft; d) a shock absorber unit disposed and coupled relative to the driven and travelling members to gradually slow down displacement of the travelling member relative to the driven member when the travelling member approaches each of said limits of displacement; and e) a centrifugal braking member coupled to the driven member to restrain rotation of the driven member above a predetermined rate of rotation thereof, said centrifugal braking member including at least one weight member pivotally attached to the driven member and spring loaded to hold a brake shoe away from an encircling member fixed to a housing of the drive member, the spring loading being such that centrifugal movement of the weight member during rotation of the driven member allows the shoe to frictionally engage a surface of the encircling member when the rate of rotation is above said predetermined rate. ### Claim 21 An electrically powered actuator, comprising: a) a bidirectional electrically powered drive member; b) a driven member coupled to the electrically powered drive member to be driven thereby; c) a travelling member engaged with the driven member and displaceable in opposite directions relative to the driven member between two limits of displacement; d) a shock absorber unit having first and second parts that are movable towards and away from each other and relative to the driven and travelling members; e) a limiter for limiting the extent of movement of said first and second parts relative to the driven member and relative to the travelling member, said limiter being coupled to the driven and travelling members such that the shock absorber unit is compressed by said limiter when the travelling member approaches each of said limits of displacement, whereby said shock absorber unit is disposed and coupled relative to the driven and travelling members to gradually slow down displacement of the travelling member relative to the driven member when the travelling member approaches each of said limits of displacement; and f) a centrifugal braking member for selectively restraining the driven member. ### Claim 22 (depends on 21) An actuator according to claim 21, wherein, in operation, the driven member is rotated by the drive member, and the centrifugal braking means is coupled to the driven member to restrain rotation of the driven member above a predetermined rate of rotation thereof. ### Claim 23 (depends on 22) An actuator according to claim 22, wherein the centrifugal braking member includes at least one weight member pivotally attached to the driven member and spring loaded to hold a brake shoe away from an encircling member fixed to a housing of the drive member, the spring loading being such that centrifugal movement of the weight member during rotation of the driven member allows the shoe to frictionally engage a surface of the encircling member when the rate of rotation is above said predetermined rate. ### Claim 24 (depends on 21) An actuator according to claim 21, wherein the driven member includes a screw-threaded shaft, and the travelling member includes a nut engaged with a thread of the shaft. ### Claim 25 (depends on 24) An actuator according to claim 24, wherein the travelling member includes a tubular member fixedly engaged at one end thereof with the nut and having a fixed seating member located at the other end thereof, the tubular member containing the shock absorber unit which is disposed in the tubular member such that the shock absorber unit is compressed between one end of the shaft and the fixed seating member when the nut is within less than a predetermined distance from the other end of the shaft. ### Claim 26 (depends on 25) An actuator according to claim 25, wherein first and second spacers are provided within the tubular member for fixing a minimum distance of separation between the nut and the shock absorber unit, and for fixing a maximum distance of separation between said one end of the shaft and the shock absorber, the arrangement of said first and second spacers being such that the shock absorber unit is compressed between the first and second spacers when the distance between the nut and said one end of the shaft is less than a predetermined amount. ### Claim 27 (depends on 26) An actuator according to claim 26, wherein the first spacer comprises an inner tubular member located within said tubular member of said travelling member and disposed between the nut and the shock absorber unit, and the second spacer comprises a spacing member attached to a body portion of the shock absorber unit and extending to a ring encircling the shaft and engageable with a stop member on said one end of the shaft. ### Claim 28 (depends on 24) An actuator according to claim 24, wherein the nut is a roller nut. ### Claim 29 (depends on 21) An actuator according to claim 21, wherein said limiter includes a first retainer for fixing a maximum distance of displacement between one of said driven and travelling members and said second part, and a second retainer for fixing a maximum distance of displacement between said second part and the other of the said driven and travelling members. ### Claim 30 (depends on 29) An actuator according to claim 29, wherein the first retainer comprises a seating member attached to said one of said driven and travelling members, and the second retainer comprises a framework attached to said second part and held on said other of said driven and travelling members. ### Claim 31 (depends on 30) An actuator according to claim 30, wherein said driven and travelling members are elongate and said other of said driven and travelling members is coaxially disposed with said one of said driven and travelling members, and the shock absorber unit is disposed between said seating member and one end of said other of the driven and traveling members. ### Claim 32 (depends on 21) An actuator according to claim 21, wherein the travelling member is engaged with the driven member for displacement of the travelling member relative to the driven member in the form of translation. ### Claim 33 (depends on 21) An actuator according to claim 21, wherein the shock absorber unit linearly decelerates the travelling member relative to the driven member when the travelling member approaches each of said limits of displacement. ### Claim 34 (depends on 21) An actuator according to claim 21, wherein a cut-off member is provided for cutting off a supply of electric power to the drive member when the travelling member approaches each of said limits of displacement. ### Claim 35 (depends on 21) An actuator according to claim 21, wherein the drive member includes a rotary member and the driven member is coupled directly to the rotary member to rotate therewith in operation.