# US 9,517,919 B2 · Elevator with adjustable buffer length > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,517,919 B2 - Document ID: US9517919B2 - Status: Granted - Kind: B2 - Application number: 14/716,530 - Filed: 2015-05-19 - Published: 2015-11-12 - Granted: 2016-12-13 - Earliest claimed: 2012-11-20 - Assignees: Kone Corporation - Applicants: KONE Corporation - Inventors: Jaakko Kalliomäki; Mikko Puranen - Web page: https://patentgrep.com/patent/US9517919B2 ## CPC - B66B 5/28: Buffer-stops for cars, cages, or skips - B66B 5/06: electrical - B66B 5/16: Braking or catch devices operating between cars, cages, or skips and fixed guide elements or surfaces in hoistway or well - B66B 5/282: {Structure thereof} - B66B: ELEVATORS; ESCALATORS OR MOVING WALKWAYS ({apparatus for raising or lowering persons on theatrical stages or the like A63J5/12} ; funicular railbound systems with rigid ground-supported tracks and cable traction, e.g. cliff railways, B61B9/00; arrangements of ammunition handlers in vessels B63G3/00; hoists, lifts, or conveyors for loading or unloading in general B65G; braking or detent devices controlling normal movements of winding drums or barrels B66D; ship-lifting devices E02C; garages for many vehicles with mechanical means for lifting vehicles E04H6/12; hoists for feeding ammunition or projectiles to launching apparatus or to loading mechanisms F41A9/00) ## Abstract An elevator includes at least one elevator car driving along an elevator shaft as well as an elevator control measuring the car position. The elevator further includes a buffer in the shaft pit, whose length is adjustable in response to the car position and car speed. Via this measure, the shaft pit can be reduced in high speed elevator requiring large buffer lengths. ## Claims ### Claim 1 An elevator comprising: at least one elevator car driving in an elevator shaft; an elevator control measuring the car position; and a buffer in a shaft pit of the elevator shaft, whereby a length of the buffer is adjustable in response to the car position, wherein the elevator control has a buffer control part which is configured to monitor the deceleration of the elevator car when approaching the lowest landing in the elevator shaft, and wherein the buffer control part is configured to decrease the buffer length if the car deceleration during approach to the lowest landing corresponds to a given slope. ### Claim 2 (depends on 1) The elevator according to claim 1, wherein the shaft pit has a smaller depth below the lowermost landing than a maximal length of the buffer. ### Claim 3 (depends on 1) The elevator according to claim 1, wherein the buffer is a hydraulic cylinder device having a cylinder and a piston, wherein a position of the piston with respect to the cylinder is adjustable. ### Claim 4 (depends on 1) The elevator according to claim 1, wherein control car position detectors are provided at different levels in the elevator shaft in a car deceleration zone above the lowest landing, which position detectors co-act with a triggering element mounted at the elevator car, wherein a reference data memory is provided in connection with the elevator control and wherein the buffer control part is configured to issue a fault action when actual car speed at the level of a position detector exceeds a corresponding reference speed from the reference data memory by a limit value. ### Claim 5 (depends on 4) The elevator according to claim 4, wherein the control car position detectors are provided additionally to an obligatory car position measuring device of the elevator. ### Claim 6 (depends on 4) The elevator according to claim 4, wherein the fault action comprises the opening of an elevator safety circuit. ### Claim 7 (depends on 4) The elevator according to claim 4, wherein the fault action comprises the activation of a buffer drive to extend the buffer length. ### Claim 8 A method for adjusting the length of a buffer in the shaft pit of an elevator shaft, said method comprising the steps of: determining the position of an elevator car; and adjusting the length of the buffer in response to the actual car position, wherein the buffer length is reduced when the elevator car approaches the lowest landing and decelerates according to a given deceleration slope. ### Claim 9 (depends on 8) The method according to claim 8, wherein the buffer is extended to its maximum length if the elevator car deviates by a limit extent from the given deceleration slope when approaching the lowermost landing. ### Claim 10 (depends on 8) The method according to claim 8, wherein the signal of position detectors in the car deceleration zone of the elevator shaft above the lowest landing is used as trigger for the elevator control to compare the actual car speed with a reference car speed corresponding to the location of the position detectors and wherein a fault action is provided if the actual car speed at said locations exceeds the reference value by a limit value. ### Claim 11 (depends on 10) The method according to claim 10, wherein the fault action comprises the driving of the buffer length to its maximal value and/or the opening of an elevator safety circuit. ### Claim 12 (depends on 2) The elevator according to claim 2, wherein the buffer is a hydraulic cylinder device having a cylinder and a piston, wherein a position of the piston with respect to the cylinder is adjustable. ### Claim 13 (depends on 5) The elevator according to claim 5, wherein the fault action comprises the opening of an elevator safety circuit. ### Claim 14 (depends on 5) The elevator according to claim 5, wherein the fault action comprises the activation of a buffer drive to extend the buffer length. ### Claim 15 (depends on 6) The elevator according to claim 6, wherein the fault action comprises the activation of a buffer drive to extend the buffer length. ### Claim 16 (depends on 8) The method according to claim 8, wherein the buffer is extended to its maximum length if the elevator car deviates by a limit extent from the given deceleration slope when approaching the lowermost landing. ### Claim 17 (depends on 1) The elevator according to claim 1, wherein the length of the buffer is adjustable in response to the car speed. ### Claim 18 (depends on 8) The method according to claim 8, further comprising the steps of: determining the speed of the elevator car; and adjusting the length of the buffer in response to the actual car speed.