# US 10,765,958 B2 · System, method, and apparatus for power limited sky diving wind tunnel drive train/fan > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,765,958 B2 - Document ID: US10765958B2 - Status: Granted - Kind: B2 - Application number: 16/373,608 - Filed: 2019-04-02 - Published: 2019-10-31 - Granted: 2020-09-08 - Earliest claimed: 2018-04-02 - Assignees: Maida Engineering, Inc. - Applicants: Maida Engineering, Inc. - Inventors: Joseph F. Maida; Arthur Armellini - Web page: https://patentgrep.com/patent/US10765958B2 ## CPC - A63G 31/00: Amusement arrangements - F04D 19/002: {Axial flow fans} - F04D 25/06: the pump being electrically driven (F04D25/08 takes precedence) - F04D 27/004: {by varying driving speed} - F04D 29/063: specially adapted for elastic fluid pumps - F16H 57/04: Features relating to lubrication or cooling {or heating} (control of lubrication or cooling in hydrostatic gearing F16H61/4165) - F16H 57/0412: {Cooling or heating; Control of temperature} - G09B 9/00: Simulators for teaching or training purposes (for the use of weapons F41; computing aspects G06; {protocols for games, networked simulations or virtual reality H04L67/131}) - A63G 2031/005: {Skydiving} - F05D 2260/4031: as in toothed gearing - F16H 2057/02078: {for wind turbines} - A63G: MERRY-GO-ROUNDS; SWINGS; ROCKING-HORSES; CHUTES; SWITCHBACKS; SIMILAR DEVICES FOR PUBLIC AMUSEMENT - F04D: NON-POSITIVE-DISPLACEMENT PUMPS (engine fuel-injection pumps F02M; ion pumps H01J41/12; electrodynamic pumps H02K44/02) - 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) - F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS ## Abstract A drive train for a wind tunnel having a nacelle housing with a fan and a fan hub assembly. The drive train comprises: a ratio gear box directly connected to the fan; and a motor disposed remote from the nacelle for powering the fan via a jackshaft and the ratio gearbox. In an embodiment, the wind tunnel has a single fan and single hub assembly. The jackshaft operatively connects the motor and gearbox. ## Claims ### Claim 1 A system for controlling a wind tunnel having a fan and nacelle, the system comprising: a) a drive end right angle thrust bearing ratio gearbox housed within the nacelle of the wind tunnel and directly connected to the fan; b) a motor disposed remote from the nacelle for powering the fan, the motor being connected to the drive end right angle thrust bearing ratio gearbox via a jackshaft so as to power the fan to rotate at at least a threshold minimum speed sufficient to enable human flight within the wind tunnel; and c) a variable frequency drive positioned remote from the wind tunnel that receives a control signal from a programmable logic controller, wherein the variable frequency drive is programmed to regulate the speed of the motor to: a) a first nonzero target motor speed which is not sufficient to cause the fan to rotate at at least the threshold minimum speed; b) a range of second target motor speeds, all second target motor speeds in the range being greater than the first nonzero target motor speed and sufficiently high to cause the fan to rotate at at least the threshold minimum speed; c) a third target motor speed of zero RPM indicative of an off condition; wherein the variable frequency drive dcvicc is programmed to operate the motor at nonzero target speeds only equal to or greater than said first nonzero target motor speed. ### Claim 2 (depends on 1) The system of claim 1, further comprising a lubrication system disposed remote from the nacelle and fluidly coupled to the drive end right angle thrust bearing ratio gearbox via a supply conduit for controllably dispensing lubricant thereto. ### Claim 3 (depends on 1) The system of claim 1, wherein the variable frequency drive includes an electronic switch electrically connected to the programmable logic controller for selectively disabling, in response to a user operation, a low control voltage of power semiconductors of an output stage of the variable frequency drive, to thereby prevent the variable frequency drive from generating a torque required to rotate the motor, without activation of a high ampere main disconnect switch. ### Claim 4 (depends on 1) The system of claim 1, wherein the system is a closed loop system defined by a first vertical flight chamber that receives air flow produced via operation of the single fan and hub assembly when operated within said range of second target motor speeds, for levitating a player within the vertical flight chamber, and wherein the nacelle containing the single fan and hub assembly is contained in a second vertical chamber conjoined to the first vertical flight chamber via air flow conduits. ### Claim 5 (depends on 1) The system of claim 1, wherein the drive end thrust right angle bearing ratio gearbox is a 2.5:1 ratio right angle gearbox, and wherein the motor connected thereto is a 500 HP, 1800 RPM motor. ### Claim 6 (depends on 5) The system of claim 5, wherein the drive end right angle thrust bearing ratio gearbox is a 2.5:1 ratio gearbox and the motor connected to the 2.5:1 ratio gearbox via said jackshaft is an open drip proof, invertor duty induction motor. ### Claim 7 (depends on 1) The system of claim 1, wherein the programmable logic controller is responsive to one or more environmental parameters for generating a control signal to the variable frequency drive to controllably adjust motor speed. ### Claim 8 (depends on 7) The system of claim 7, wherein a lubrication system disposed remote from the nacelle and fluidly coupled to the drive end right angle thrust bearing ratio gearbox via a supply conduit for controllably dispensing lubricant thereto, and wherein the programmable logic controller is responsive to one or more of temperature, pressure, leakage, and flow parameters output from the lubrication system for generating a control signal to the variable frequency drive to controllably adjust motor speed. ### Claim 9 (depends on 7) The system of claim 7, wherein one or more horizontal and vertical vibration sensors are positioned about the motor for sensing motor vibration and providing one or more output signals whose amplitudes are indicative of the level of vibration sensed, and wherein the programmable logic controller is responsive to the output signals of said vibration sensors for generating a control signal to the variable frequency drive to stop the motor when the output signal amplitude exceeds a predetermined threshold indicative of a high vertical or high horizontal motor vibration level. ### Claim 10 (depends on 1) The system of claim 1, wherein the first nonzero target motor speed is 500 RPM. ### Claim 11 (depends on 1) The system of claim 1, wherein a lubrication system is disposed remote from the nacelle and fluidly coupled to the drive end right angle thrust bearing ratio gearbox via a supply conduit for controllably dispensing cooled lubricant thereto, wherein a return conduit returns lubricant from said ratio gearbox to said lubrication system, and wherein a cooling unit cools the returned lubricant prior to recirculation to said ratio gearbox, thereby maintaining flow and temperature of the ratio gearbox. ### Claim 12 (depends on 7) The system of claim 7, wherein one or more horizontal and vertical vibration sensors are positioned about the ratio gearbox for sensing gearbox vibration and providing one or more output signals whose amplitudes are indicative of the level of vibration sensed, and wherein the programmable logic controller is responsive to the output signals of said vibration sensors for outputting a control signal to the variable frequency drive to stop the motor when the output signal amplitude exceeds a predetermined threshold indicative of a high vertical or high horizontal gearbox vibration level. ### Claim 13 A system for controlling a wind tunnel having a fan and nacelle, the system comprising: a drive end right angle thrust bearing ratio gearbox housed within the nacelle of the wind tunnel and directly connected to the fan; a motor disposed remote from the nacelle for powering the fan, the motor being connected to the ratio gearbox via a jackshaft; and a variable frequency drive positioned remote from the wind tunnel and configured to regulate the speed of the motor within a minimum and maximum operational range of the motor; wherein a lubrication system disposed remote from the nacelle is fluidly coupled to the ratio gearbox for controllably dispensing lubricant thereto via a supply conduit, and wherein a programmable logic controller is responsive to one or more of temperature, pressure, leakage, or flow parameters output from the lubrication system for generating a control signal to the variable frequency drive to controllably adjust motor speed. ### Claim 14 (depends on 13) The system of claim 13, wherein one or more horizontal and vertical vibration sensors are positioned about the motor for sensing motor vibration and providing one or more output signals whose amplitudes are indicative of the level of vibration sensed, and wherein the programmable logic controller is responsive to the output signals of said vibration sensors for outputting a control signal to the variable frequency drive to stop the motor when the output signal amplitude exceeds a predetermined threshold indicative of a high vertical or high horizontal motor vibration level. ### Claim 15 (depends on 13) The system of claim 13, wherein the drive end right angle thrust bearing ratio gearbox is a 2.5:1 ratio gearbox. ### Claim 16 (depends on 13) The system of claim 13, wherein a return conduit returns lubricant from said ratio gearbox to said lubrication system, and wherein a cooling unit cools the returned lubricant prior to recirculation to said ratio gearbox via said supply conduit, thereby maintaining flow and temperature of the ratio gearbox. ### Claim 17 (depends on 13) The system of claim 13, wherein one or more horizontal and vertical vibration sensors are positioned about the ratio gearbox for sensing gearbox vibration and providing one or more output signals whose amplitudes are indicative of the level of vibration sensed, and wherein the programmable logic controller is responsive to the output signals of said vibration sensors for outputting a control signal to the variable frequency drive to stop the motor when the output signal amplitude exceeds a predetermined threshold indicative of a high vertical or high horizontal gearbox vibration level. ### Claim 18 (depends on 13) The system of claim 13, wherein said variable frequency drive receives a control signal from a programmable logic controller, wherein the variable frequency device is programmed to adjust the speed of the motor to a) a first nonzero target motor speed which is not sufficient to cause the fan to rotate at at least a threshold minimum speed enabling human flight within the tunnel; b) a range of second target motor speeds, all second target motor speeds in the range being greater than the first nonzero target motor speed and sufficiently high to cause the fan to rotate at at least the threshold minimum speed; c) a third target motor speed of zero RPM indicative of an off condition; wherein the variable frequency drive is programmed to operate the motor at nonzero target speeds only equal to or greater than said first nonzero target motor speed. ### Claim 19 (depends on 18) The system of claim 18, wherein a potentiometer adjustable via a user interface coupled to the programmable logic controller sets the second target motor speed. ### Claim 20 (depends on 13) The system of claim 13, wherein the variable frequency drive includes an electronic switch electrically connected to the programmable logic controller for selectively disabling, in response to a user operation, a low control voltage of power semiconductors of an output stage of the variable frequency drive, to thereby prevent the variable frequency drive from generating a torque required to rotate the motor, without activation of a high ampere main disconnect switch. ### Claim 21 (depends on 13) The system of claim 13, wherein a first set of bolts connect through a fan hub assembly to the gearbox for securing the fan hub assembly to the gearbox.