Hydraulic elevator

Claim 2

A hydraulic elevator comprising: a load support for allowing persons or objects to be carried thereby; expansible chamber means being drivingly connected to said load support for moving said load support upwardly during expansion and downwardly during discharge; variable capacity pump means for supplying fluid under pressure into said expansible chamber during upward movement of the elevator through means for conducting said fluid from said pump means; means drivingly connected to said pump means for controlling the flow rate of fluid pumped through controlling the capacity of said pump means to control the speed of ascent of the elevator; throttle means for throttling the flow of fluid from said expansible chamber; means for discharging fluid from said expansible chamber, said discharging means including means for controlling the speed of descent of the elevator through controlling the flow of fluid discharged from said expansible chamber, which means for controlling the speed of descent comprises said pump means, said means for controlling the flow of fluid and said throttle means.

Claim 3

A hydraulic elevator as defined in claim 1, wherein said throttle means controls the deceleration of said elevator at least during descent by varying the throttling of the working fluid discharging from said expansible chamber; and only said means for controlling the flow rate being operative to control both the acceleration and steady running speed of said elevator during descent without throttling by controlling the flow rate through said pump means from said expansible chamber means.

Claim 4

The hydraulic elevator as defined in claim 1, including passage means for conducting substantially all of the fluid discharging from said expansible chamber means through said throttle means during deceleration of the elevator descent.

Claim 5

The hydraulic elevator as defined in claim 3, wherein said passage means further conducts all of the fluid discharged from said expansible chamber through said pump means and by-passes said throttle means during acceleration of the elevator descent and during steady running speed of the elevator descent.

Claim 6

The hydraulic elevator as defined in claim 4, wherein said passage means further conducts all of the working fluid through said pump means to said expansible chamber during acceleration of the elevator ascent and during steady running of the elevator ascent, and further by-passing said throttle means.

Claim 7

The hydraulic elevator as defined in claim 5, wherein said passage means further conducts all of the fluid from said pump means to said expansible chamber by-passing said throttle means during deceleration of the elevator ascent.

Claim 8

The hydraulic elevator as defined in claim 5, wherein said passage means further conducts fluid from said pump means to both said throttle means and said expansible chamber means during deceleration of said elevator ascent; and said throttle means varying the throttling of the working fluid passing therethrough and discharging the throttled fluid away from said expansible chamber means during deceleration of the elevator ascent.

Claim 9

The hydraulic elevator as defined in claim 1, wherein said throttle means during deceleration of said elevator at descent has a maximum pressure differential of the working fluid being throttled that is a little less than the pressure within the expansible chamber of the elevator under no load conditions.

Claim 10

The hydraulic elevator as defined in claim 1, wherein said pump means includes A variable speed positive displacement pump having a constant fluid delivery for each speed of operation, power means for driving said pump, and a fly wheel drivingly connected with said power means and pump; said pump means delivering all of its fluid to said expansible chamber during acceleration of ascent to correspondingly determine the acceleration of said elevator during ascent.

Claim 11

The hydraulic elevator as defined in claim 9, wherein said power means is an electric motor having means for controlling its starting voltage with a variable resistance to correspondingly control the starting torque of said motor.

Claim 12

The hydraulic elevator as defined in claim 1, wherein said pump means includes a variable speed positive displacement pump having a constant fluid delivery for each speed of operation and power means for driving said pump.

Claim 13

A hydraulic elevator, comprising: a load support for allowing persons or objects to be carried thereby; expansible chamber means being drivingly connected to said load support for moving said load support upwardly with expansion and downwardly with discharge; a positive displacement pump means having a constant fluid delivery for each corresponding constant speed of operation, an inlet and an outlet; liquid storage tank means for providing a supply in reserve of working liquid therein; first liquid passage means establishing liquid communication from said liquid tank means through said pump means to said expansible chamber means; check valve means operatively mounted within said first liquid passage means between said pump means outlet and said expansible chamber means for normally permitting the flow of liquid only from said pump means to said expansible chamber means only when the pressure of the working liquid flowing from said pump means is higher than a predetermined pressure; flow means for freely passing liquid in either direction between said pump means outlet and said expansible chamber regardless of pressure upon being selectively actuated by a predetermined signal; change-over valve means further connected within said first liquid passage means between said check valve means and said pump means; throttle valve means having an outlet connected to said tank means and and an inlet; second liquid passage means providing fluid communication between said change-over valve means, liquid storage tank means and throttle valve means in parallel with said pump means; said change-over valve means having one position for supplying all of the working liquid from said pump means into and out of said expansible chamber when the pressure of the working liquid from said pump means is greater than said predetermined pressure to pass through said check valve and blocking fluid communication between said expansible chamber and throttle means at least during acceleration of ascent and descent of the elevator; and said change-over valve means having a second position for conducting the working liquid from said expansible chamber means during discharge into said liquid tank means through both said pump means and said throttle valve means in parallel at least during deceleration of the descent of the elevator.

Claim 14

A hydraulic elevator, comprising: a load support for allowing persons or objects to be carried thereby; expansible chamber means being drivingly connected to said load support for moving said load support upwardly with expansion and downwardly with discharge; a positive displacement pump means having a constant fluid delivery for each corresponding constant speed of operation, an inlet and an outlet; liquid storage tank means for providing a supply in reserve of working liquid therein; first liquid passage means establishing liquid communication from said liquid tank means through said pump means to said expansible chamber means; check valve means operatively mounted within said first liquid passage means between said pump means outlet and said expansible chamber means for normally permitting the flow of liquid only from said pump means to said expansible chamber means only when the pressure of the working liquid flowing from said pump means is higher than a predetermined pressure; flow means for freely passing liquid in either direction between said pump means outlet and said expansible chamber regardless of pressure upon being selectively actuated by a predetermined signal; change-over valve means further connected within said first liquid passage means between said check valve means and said pump means; throttle valve means having an outlet connected to said tank means and and an inlet; second liquid passage means providing fluid communication between said change-over valve means, liquid storage tank means and throttle valve means in parallel with said pump means; said change-over valve means having one position for supplying all of the working liquid from said pump means into and out of said expansible chamber when the pressure of the working liquid from said pump means is greater than said predetermined pressure to pass through said check valve and blocking fluid communication between said expansible chamber and throttle means at least during acceleration of ascent and descent of the elevator; and said change-over valve means having a second position for conducting the working liquid from said expansible chamber means during discharge into said liquid tank means through both said pump means and said throttle valve means in parallel at least during deceleration of the descent of the elevator.

Claim 15

The hydraulic elevator as defined in claim 12 wherein said change-over valve means further conducts a portion of the working liquid from the outlet of said pump means and returns it to said liquid tank means through said throttle valve means, and said throttle valve means gradually increases the throttling of the working liquid passing through said throttle valve during deceleration of the elevator ascent.

Claim 16

A hydraulic elevator, comprising: a load support for allowing persons or objects to be carried thereby; expansible chamber means being drivingly connected to said load support for moving said load support upwardly with expansion and downwardly with discharge; a positive displacement pump means having a constant delivery for a corresponding constant speed, an inlet and an outlet; liquid storage tank means for proviDing a supply in reserve of working liquid therein; first liquid passage means establishing liquid communication from said liquid tank means through said pump means to said expansible chamber; first check valve means operatively mounted within said liquid passage means between said pump means outlet and said expansible chamber means for normally permitting the flow of liquid only from said pump means to said expansible chamber means only when the pressure of the working liquid flowing from said pump means is higher than a predetermined pressure; flow means freely passing liquid in either direction between said pump means and said expansible chamber regardless of pressure upon being selectively actuated by a predetermined signal; second check valve means in fluid communication between said first check valve means and said pump means outlet within said first passage means for permitting liquid from said first check valve means to communicate with said pump means only when pressure of the working liquid from said pump means is higher than a predetermined pressure; throttle valve means parallel with said first passage means; change-over valve means; second liquid passage means conducting liquid from between said first and second check valve means to said liquid tank means through said throttle valve means and said change-over valve means; third liquid passage means for conducting liquid between said second liquid passage means and said pump means through said change-over valve means; said change-over valve means, passage means and check valve means supplying all of the liquid through said pump means to and from said expansible chamber through said first and second check valve means at least during both acceleration and rated running of ascent and descent, respectively of the elevator; and said change-over valve means and passage means conducting the working liquid from said expansible chamber and discharging it into said liquid tank through said change-over check valve means, both said throttle valve means and said pump means in parallel, and said first check valve means at least during deceleration of descent of the elevator.

Claim 17

A hydraulic elevator, comprising: a load support for allowing persons or objects to be carried thereby; expansible chamber means being drivingly connected to said load support for moving said load support upwardly with expansion and downwardly with discharge; a positive displacement pump means having a constant delivery for a corresponding constant speed, an inlet and an outlet; liquid storage tank means for proviDing a supply in reserve of working liquid therein; first liquid passage means establishing liquid communication from said liquid tank means through said pump means to said expansible chamber; first check valve means operatively mounted within said liquid passage means between said pump means outlet and said expansible chamber means for normally permitting the flow of liquid only from said pump means to said expansible chamber means only when the pressure of the working liquid flowing from said pump means is higher than a predetermined pressure; flow means freely passing liquid in either direction between said pump means and said expansible chamber regardless of pressure upon being selectively actuated by a predetermined signal; second check valve means in fluid communication between said first check valve means and said pump means outlet within said first passage means for permitting liquid from said first check valve means to communicate with said pump means only when pressure of the working liquid from said pump means is higher than a predetermined pressure; throttle valve means parallel with said first passage means; change-over valve means; second liquid passage means conducting liquid from between said first and second check valve means to said liquid tank means through said throttle valve means and said change-over valve means; third liquid passage means for conducting liquid between said second liquid passage means and said pump means through said change-over valve means; said change-over valve means, passage means and check valve means supplying all of the liquid through said pump means to and from said expansible chamber through said first and second check valve means at least during both acceleration and rated running of ascent and descent, respectively of the elevator; and said change-over valve means and passage means conducting the working liquid from said expansible chamber and discharging it into said liquid tank through said change-over check valve means, both said throttle valve means and said pump means in parallel, and said first check valve means at least during deceleration of descent of the elevator.

Claim 18

A hydraulic elevator as defined in claim 14, further being provided with a change-over valve for by-passing liquid around said pump means.

Claim 19

A hydraulic elevator, comprising: a load support for allowing persons or objects to be carried thereby; expansible chamber means being drivingly connected to said load support for moving said load support upwardly with expansion and downwardly with discharge; positive displacement pump means having a constant delivery for a corresponding constant speed, an inlet and outlet; liquid storage tank means for providing a supply in reserve of working liquid therein; liquid passage means establishing liquid communication from said liquid tank means through said positive pump means to said expansible chamber means; check valve means operatively mounted within said liquid passage means between said pump means outlet and said expansible chamber means for normally permitting the flow of liquid only from said pump means to said expansible chamber means only when the pressure of the working liquid flowing from said pump means is higher than a predetermined pressure; flow means freely passing liquid in either direction between said pump means and said expansible chamber regardless of pressure upon being selectively actuated by a predetermined signal; variable throttle valve means in liquid communication between said check valve means and said pump means outlet; means for controlling the speed of the elevator by correspondingly controlling the flow of liquid into and out of said expansible chamber at least during acceleration and rated running of both ascent and descent of the elevator by only controlling the pumping of the liquid with said pump means without throttling; and said means for further controlling at least the deceleration of the descent speed of the elevator by controlling the discharge of liquid from said expansiblE chamber through said pump means and said throttle valve means with throttling.

Claim 20

A hydraulic elevator, comprising: a load support for allowing persons or objects to be carried thereby; expansible chamber means being drivingly connected to said load support for moving said load support upwardly with expansion and downwardly with discharge; positive displacement pump means having a constant delivery for a corresponding constant speed, an inlet and outlet; liquid storage tank means for providing a supply in reserve of working liquid therein; liquid passage means establishing liquid communication from said liquid tank means through said positive pump means to said expansible chamber means; check valve means operatively mounted within said liquid passage means between said pump means outlet and said expansible chamber means for normally permitting the flow of liquid only from said pump means to said expansible chamber means only when the pressure of the working liquid flowing from said pump means is higher than a predetermined pressure; flow means freely passing liquid in either direction between said pump means and said expansible chamber regardless of pressure upon being selectively actuated by a predetermined signal; variable throttle valve means in liquid communication between said check valve means and said pump means outlet; means for controlling the speed of the elevator by correspondingly controlling the flow of liquid into and out of said expansible chamber at least during acceleration and rated running of both ascent and descent of the elevator by only controlling the pumping of the liquid with said pump means without throttling; and said means for further controlling at least the deceleration of the descent speed of the elevator by controlling the discharge of liquid from said expansiblE chamber through said pump means and said throttle valve means with throttling.

Claim 23

The method of claim 17, wherein said step of controlling the deceleration of descent further passes at least some of the fluid discharged from said expansible chamber reversely through said pump and further controls the rate of flow of said pump.

Claim 24

The method of claim 18, including the further step of controlling the deceleration of elevator ascent by throttling at least some of the fluid discharged from said pump.

Claim 25

The method of claim 17, including the further step of controlling the deceleration of elevator ascent by throttling at least some of the fluid discharged from said pump.