US2359112A - Hydraulic elevator - Google Patents

Description

Sept. 26, 1944. F. HYMANS HYDRAULIC ELEVATOR Filed Aug. 14, 1943 2 Sheets-Sheet 1 INVENTOR ATTORNEY PM H BY I W F. HYMANS HYDRAUL I C ELEVATOR Sept. 26, 1944.

Filed Aug. 14, 1943 2 Sheets-Sheet 2 1'; Z WW INVENTOR BY mu! .44All- 1 ATTORNEY Patented Sept. 26, 1944 UNITED STATES PATENT OFFICE HYDRAULIC ELEVATOR Frederick Hymans, Larchmont, N. Y., assignor to Otis Elevator Company, New York, N. Y., a corporation of New Jersey Application August 14, 1943, Serial No..498,904

6 Claims.

The invention relates to hydraulic elevators.

There are certain advantages in hydraulic elevators, especially for low rise installations. Such elevators arev particularly suitable for installation on ships and in certain categories are required. In certain type ships such as naval vessels, counterweights for the cars are not permitted, thereby adding to the power required to operate th elevator. For exceptionally heavy duties on ships of this character, as for example elevators for carrying airplanes on airplane carriers, the power required to operate the elevator is considerable. Also, speed of operation is important so-that it is desirable to operate the car at a fast speed between the transfer decks and at a slow speed preparatory to stopping the car. Furthermore, it is important that the car platform be kept level with the transfer decks in order that the transfer of the planes may be readily made and, in the case of the upper transfer or flight deck, in the event that an airplane should land on this deck.

It is the principal object of the invention to provide a hydraulic elevator in which the car may be operated at a fast speed between landings and at a slow speed as it approaches the landing at which a stop is to be made, in which the car platform is maintained level with the landings when stopped and in which the power required to operate the elevator is minimized.

In carrying out the invention, according to the embodiment which will be described, a hydraulic counterpoise is provided for the elevator car in the form of a tank containing fluid under pressure. Pumps are provided between the tank and the lifting cylinder for effecting fluid transfer therebetween. One of these pumps is of relatively small capacity and is utilized for operating the elevator car at a slow speed preparatory to stopping. The invention will be described as applied to an installation in which the elevator platform is utilized to transfer airplanes between a hangar deck and a flight deck. To maintain the platform level with the flight deck an accumulator is employed in conjunction with the small pump to hold the platform against stops associated with the flight deck.

Features and advantages of the invention will be apparent from the above statements, the description which follows and appended claims.

In the drawings:

Figure l is a diagrammatic representation of a hydraulic elevator installation embodying the invention; and

Figure 2 is a schematic wiring diagram of a simple electrical control system for the elevator, illustrating interconnections for the various elevator control devices.

Referring first to Figure '1, the elevator installation illustrated is one in which the elevator platform i0 is utilized to carry airplanes from the hangar deck ll of an airplane carrier to the flight deck l2 and to return them from the flight deck to the hangar deck. Also the elevator is illustrated as of the plunger type. The plunger i3 is secured at the top to the platform In from which it extends downwardly into the cylinder M through a stufling box IE. Extensions I6 are provided on the platform for engaging the bottom of the flight deck which forms stops to align the platform with the flight deck. Pads I'l are provided on the bottom of the platform which engage stops i8 below the level of the hangar deck to align the platform with the hangar deck.

Cylinder I4 is connected to a reservoir 20. One connecting path is by way of pipe 2| through a poppet valve 22 and the main pump 23 to another pipe 24 connected to tank 20 near the bottom thereof. The pump is illustrated as a gear pump driven by an electric motor 25 and provided with an electromechanical brake 26 for bringing the pump to a stop. The poppet valve is illustrated as of the balanced pressure type, operated by an electromagnet 2! and biased to closed position by a spring 28. The poppet valve is bypassed by a check valve 30 by way of pipes 3i and 32. The check valve is illustrated as of the hinged type.

Another connecting path between the cylinder and the reservoir is by way of pipes 2|, 3| and 33 through a poppet valve 34 and auxiliary pump 35 to pipe 24. Pump 35 may also be a gear pump driven by an electric motor 36 and provided with an electromechanical brake 31. The poppet valve may be of the same type as valve 22, its operating electromagnet being designated 40. It also is by-passed, the by-pass being by way of pipe 38 through a check valve 4| which may be of the hinged type.

The reservoir 20 is illustrated as in the form of a vertical tank, partially filled with liquid 42, such as oil, for operating the elevator. Above the liquid level is air 43 under pressure. The pipe 44 indicates a source of air supply for providing the desired pressure in the tank.

The pipe 3! is connected to an accumulator 45. This accumulator is illustrated as in the form of a cylinder '46 to which pipe 3| is connected and having a plunger 41 operating therein.- The end down to a low speed determined by the capacity of the auxiliary pump.

As-the platform reaches the level of the flight deck its extensions ll engage the bottom of the flight deck to bring the platform to a stop. The

auxiliary pump continues in operation, however,

tending between them.- It is to be understood that the cylinder and reservoir are provided with suitable stumng boxes; not shown.

The main pump 23 is provided with a relief valve 58. This valve is illustrated as in the form of a valve member I biased to closed position by a spring I8. Thevalve is illustrated as arranged in a pipe '1 connecting pipe 2| adjacent the'main pump to reservoir 2| at the bottom thereof. A' similar relief valve ll is'provided for\ auxiliary pump 35 and is arranged in a pipe is connecting pipe 33 adjacent the auxiliary pump to the reservoir at the bottom thereof. Instead of 'extending to the reservoir... pipes 51 and Ill may discharge into open tanks. A relief .valve II is provided for reservoir 20.

Referring now also to Figure 2, push buttons are illustrated for exercising manual control of the operation of the elevator. These'push butsupplying oil to the cylinder 46 of the accumulator. The oil thus supplied forces plunger '41 outwardly from the cylinder and thus plunger ll farther into reservoir I! against the existing air pressure. When the accumulator plunger 41 has been moved outwardly a-certain amount so that a considerable quantity of oil has accumulated in cylinder ll, cam '|i causes opening of switch II to'break the circuit for the coil oi'switch H to cause deenergization of motor as and the release coil /'of brake 31 .to bring the auxiliary motor to a' stop. The air pressure in reservoir 50 is suflicient to maintain enough pressure in cylinder H to hold the platform against the flight deck even when a plane lands on the platform.

- This is the condition of the system as illustrated in Figure 1. As leakage of 'oil takes place in the tons are arranged in the elevator platform aha-- the platform atany point. Blowing down of the elevator as it nears the flight deck is effected by I means of a switch I operated by a cam I! carried by the platform. A similar switch I1 is operated by the cam to slow down the platform as it nears the hangar deck. Cam l6 operates a second switch II as the platform reachesthe hanger deck to stop the platform. A stem "extends main cylinder is plunger 41 is forced back into cylinder M by the air pressure in reservoir ll, causing the reclosing of switch 12. This reestablishes the circuit for the coil of switch H which operates to restart the auxiliary pump. This renews the oil in the accumulator, and this oper-. ation is repeated so long as the platform remains at the flight deck, thereby assuring the platform being maintained level with the flight deck at all times,

To lower the platform, do'wn button II is pressed. This completes the circuit for the coil of-switch'D whichoperates to causev release of electromechanical brake l and to cause current to be supplied to motor II for rotation clockwise as viewed in Figure 1. At the same time switch upwardly from plunger 41 and has a cam 'II' on 40 D causes energization of operating magnet 21 the upp r end thereof for operating a switch-I2 to stop the auxiliary pump is when suflicient oil has been forced into cylinder 40 to move plunger 41 downri'va'rdly far enough for can II to operate switch] Assume that the platformis at deer and that itis desired to'raise it to the flight deck.

The up button O2 ispressed. buttons-eta through electrom netic switch U- to cause env ergisationof the release coil for-the, electrome-\ chanical-brake fl to'release the brake and to cause'current to be supplied to motor 25 for rotaof poppet valve 22 to open this valve. The main pump being rotated in a direction to return oil to reservoir 2|, oil flows from cylinder It by way of pipe 2|, through poppet valve 22 (check valve II preventing the flow of oil by way of pipe I!) pipe It to the bottom of reservoir 20. Assuming that, asillustrated in Figure 2, down button 08 also operation 01E switch D', brake 31 is tion counterclockwise, as viewed in Figure 1. This causes operation of the main pump to force 011 by way of pipe 2|, pipe 82 through check valve ll, pipe ll,'and thence again to'pipe and into cylinder 'II. This forces plunger l3 upwardly to raise platform II. It will be assumed that as illustrated in the wiring diagram the control is arranged so that button '82. also acts through electromagnetic switch U to cause energization of the release coil of brake 31 and to cause-current to be supplied to motor I! to operate auxiliary pump it to force oil by way of pipe 38, pipe "through check valve ll, pipe II and pipell to stop .the main pump. The auxiliary pump 35,

released-and motor It is energized for clockwise so'that oil-also flows by way of'plpeli valve 3, opened as the result of the eriergiaation. of its operating electromagnet 4| along with energisation of motor II. to the reservoir.

.As the-platform hangar'deck, cam

. u opens switch s1 which breaks the circuit for the coil of switch I), deener'gising electromagnet 2I, motor It and the releaseooil for brake 2|. Thu the main pump is'stopp d andpopp t valve 22 is closed. The a x a pump continues in operation, however, so that oil is returned in reduced volume from the cylinder to the reservoir II. This slows down the platform to a low speed. Just before the pads ll engage stops ll,

' cam ll opens switch ll which breaks the circuit for thecoil of switch D, deenergizing motor 00 and the release coil of brake 81 and the brake is applied to bring the auxiliary pump to a stop. At the same time poppet valve 34 closes. It is to be understood that suflicient timing is provided, as by pro d s a condenser in parallel to the coil ofswitch D to delay the dropping out of electromagnetic switching mechanism however, operates to supply oil in reduced'volume to the cylinder. As a result the platform is slowed controlled by switch II, to enable the continued operation of the auxiliary pump suflieient to bring pads ll against the stops and thus align the platform with the hangar deck. 4

Pressure of the air in reservoir II is such that the pressure exerted by the oil in cylinder ll is somewhat less than the weight of plunger I3 and unloaded platform It and apparatus carried thereby. when the pumps are rotatedio raise the platform they act to build up the pressure to a point sufficient to effect this operation. The capacity of the reservoir is such that the volume of air is large as compared with the change in the volume of oil in moving the platform from one deck to another. Thus the Variation in pressure in the reservoir in eifecting such movement is not very great. The pressure in the reservoir may, therefore, be considered as a hydraulic counterpoise and the power of the pump driving motors need only be sumcient for handling the net load.

In lowering the platform, inasmuch as the pressure under the plunger is greater than that in the reservoir, the pumps serve to regulate the speed of descent. Since the speed of the elevator platform is in proportion to the speed of the pump driving motors there will be very little variation in the speed with or without load for each direc- I tion of travel.

The check valves 30 and ll act to prevent oil returning from the cylinder to the reservoir by way of the pumps when the pumps are stopped. The relief valves 53 and 58 open in case of abnormal pressure. If, for example, a pump should continue in operation to pump oil from the reservoir and thus build up pressure after the control mechanism has acted to cause it to stop, its relief valve opens when the pressure reaches a certain point. Also should a pump be operated with a shut-off valve (not shown) on the cylinder side of the pump closed, its relief valve opensto relieve the pressure.

While described as applied to an elevator utilized for raising and lowering airplanes it is to be understood that the invention may be applied to other types of elevator installations. Also the invention may be applied to other types of hydraulic lifting mechanism, as for example horizontal hydraulic engines with roping. While only two landings are illustrated, it is to be understood that the elevator may be arranged to serve more than two landings. Pumps of types other than gear pumps may be utilized for effecting the transfer of oil from and to the reservoir. Two or more main pumps in parallel lines may be utilized instead of the single pump illustrated in which event it would be preferred to have separate driving motors and brakes for each pump with separate electromagnetic control switches therefor. In such an arrangement these pumps could be cut off one at a time to slow down the platform in steps. Variations may be made in the construction of valves illustrated, it being understood that the valves shown are diagrammatic and are for the purpose of illustrating the operation.

The accumulator I5 is an important feature of the invention, especially for airplane elevators on carriers where it is important that the platform be kept level with the flight deck and maintained so even under conditions where a plane should alight on th platform. However, the

construction of the accumulator may be varied, it being understood that the arrangement shown is diagrammatic and for the purpose of illustrating the operation of the invention.

As many changes could be made in the above construction and many apparently widely diiferent embodiments of this invention could be made without departing from the scope thereof,- it is intended that all matter contained in the above description or shown in the accompanyin drawings shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1 1. An airplane transporting elevator for an airplane carrier comprising; a platform serving a flight deck and a hangar deck; a plunger extending downwardly from the platform; a cylinder for said plunger; a reservoir containing 011 and air under pressure above the oil; main pumping mechanism connected on one side to said cylinder and on the other side to said reservoir; auxiliary pumping mechanism connectedon one side to said cylinder and on the other side to said reservoir; means for causing operation of said pumping mechanisms to transfer 011 from the reservoir to said cylinder to raise said platform; means operable as the platform nears the flight deck to cause stopping of the main pumping mechanism to slow down the platform; and means for stopping the platform when it becomes level with the flight deck.

2'. An airplane transporting elevator for an airplane carrier comprising; a platform serving a flight deck and a hangar deck; a plunger extending downwardly from the platform; a cylinder for said plunger; a reservoir containing oil and air under pressure above the oil main pumping mechanism connected on one side to said cylinder and on the other side to said reservoir; auxiliary pumping mechanism connected on one side to said cylinder and on the other side to said reservoir; means for causing operation of said pumping mechanisms to transfer oil from the reservoir to said cylinder to raise said platform; means operable as the platform nears the flight deck to cause stopping of the main pumping mechanism to slow down the platform; means for stopping the platform when it becomes level with the flight deck; an accumulator having a chamber connected to said cylinder for storing oil under pressure upon operation of the auxiliary pumping mechanism after the platform has stopped; and means responsive to the volume of oil in said chamber to cause stopping of the auxiliary pumping mechanism when said oil in the chamber reaches a certain volume and to cause restarting of the auxiliary pumping mechanism when said oil in said chamber decreases to below said certain volume.

3. An airplane transporting elevator for an airplane carrier comprising; a platform serving a flight deck and a hangar deck; a plunger extending downwardly from the platform; a cylinder for said plunger; a reservoir containing oil and air. under pressure above the oil; main pumping mechanism connected on one side to said cylinder and on the other side to said reservoir; auxiliary Du ping mechanism connected on one side to said cylinder and on the other side to said reservoir; means for causing operation of said pumping mechanisms to transfer oil from the reservoir to said cylinder to raise said platform; means operable as the platform nears the flight deck to cause stopping of the main pumping mechanism to slow down the platform; means for stopping the platform when it becomes level with the flight deck; an accumulator having an oil chamber connected to said cylinder and adapted in conjunction with said auxiliary pumping mechanism to maintain sufiicient oil pressure in said tending downw cylinder to hold said platform level with the flight deck, said accumulator also having an air chamber containing air under pressure against which oil is forced into said oil chamber; and means operable when the accumulator has received a certain amount of oil to cause stopping of the auxiliary pumping mechanism and also operable when the amount of oil in the accumulator has decreased a certain amount to restart the auxiliary pumping mechanism.

7 4. An airplane transporting elevator for an airplane carrier comprising; a platform serving a flight deck and a hangar deck; a plunger extending downwardly from the platform; a cylinder for said plunger; a reservoir containing oil and air under pressure above the oil; main pumpingmechanism connected on one side to said cylinder and on the other side to said reservoir; auxiliary pumping mechanism connected on one side to said cylinder and on the other side to said reservoir; means for causing operation of said pumping mechanisms to transfer oil from the reservoir to said cylinder to raise said platform; means operable as the platform nears the flight deck to cause stopping of the main pumping mechanism to slow down the platform; means for stopping the platform when it becomes level with the flight deck; an accumulator having an oil chamber connected to said cylinder and adapted in conjunction with said auxiliary pumping mechanism to maintain suflicient oil pressure in said cylinder to hold said platform level with the flight deck, said accumulator also having an air chamber containing air under pressure against which 011 is forced into said oil chamber; means operable when the accumulator has received a certain amount of oil to cause stopping of the auxiliary pumping mechanism and also operable when the amount of oil in the accumulator has decreased a certain amount to restart the auxiliary pumping meching mechanisms to transfer oil from the cylinder to said reservoir to lower said platform; means operable as the platform nears the hangar deck to cause stopping of the main pumping mechanism to slow down the platform; and means operable as the platform arrives at the hangar .deck to cause stopping of the auxiliary pumping mechanism to stop the platform.

5. An' lane transporting elevator for an airplane c rrier comprising; a platform serving a flight deck a hangar deck; a plunger exdly from the platform; a cylinder for said plunger; a reservoir containing oil and air under pressure above the oil;- oil conductin: means between said cylinder and said reservoir; additional 011 conducting means between. said cylinder and said reservoir; a main pump in the first named conducting means;.an auxiliary pump in said additional conducting means; valve means for said main pump in said first named conducting means between the pump and the cylinder; valve means for said auxiliary pump in said additional conducting means between the v pump and the cylinder; means for causing operation of said pumps to transfer oil from the reservoir to said cylinder to raise said platform; means operable as the platform nears the flight deck to cause stopping of the main pump to slow down the platform; means for stopping the platform when it becomes level with the flight deck;

I anism; means for causing operation of said pumpthe oil in said cylinder under operation of the auxiliary pump after the platform has stopped; means operable when the accumulator has acquired a certain amount of oil to cause stopping of the auxiliary pump and also operable whenthe amount of oil in the accumulator has decreased a certain amount to restart the auxiliary pump: means for causing operation of said pumps to transfer oil from the cylinder to said reservoir to lower said platform; means operable as the platform nears the hangar deck to cause stopping of the main pump to slow down the platform: and means operable as the platform arrives at the hangar deck to cause stopping of the auxiliary pump to stop the platform.

6. An airplane transporting elevator for an airplane carrier comprising; a platform serving a flight deck and a hangar deck; a plunger extending downwardly from the platform; a cylinder for said plunger; a reservoir containing a certain percentage by volume of oil and a larger percentage by volume of air under pressure above the oil; a main pump; a pipe line connecting one side of the pump to said cylinder and the other side of the pump to the oil containing portion of said reservoir; a p p t valve in said pipe line between the main pump and the cylinder; .a by-pass for the poppet valve, said by-pass including a. check valve biased to prevent the flow of oil therethrough from the cylinder to the pump; an auxiliary pump; a pipe line connecting one side of the auxiliary pump to said cylinder and the other side to the oil containing portion of said reservoir; a poppet valve in the last named pipe line between the auxiliary pump and the cylinder; a by-pass for the last named poppet (valve, said by-pass including a check valve biased to prevent the flow of oil therethrpugh from the cylinder to the pump; means for causing operation of said pumps to build up the pressure of oil in said cylinder and transfer oil from the reservoir through the check valves to said cylinder to raise said platform; means operable as the platform nears the flight deck to cause stopping of the main pump to slow down the platform; means for stopping the platform when it becomes levelwith the flight deck; an accumulator connected tosaid cylinder and auxiliary pump by the last named pipe line for building up the pressure of the oil in said cylinder under operation of the auxiliary pump after the platform has stopped; means operable when the accumulator has acquired a certain amount of oilto cause stopplns of the auxiliary pump and also operable when the. amount of oil in the accumulator has decreased a certain amount to restart the auxiliary pump; means for causing opening of said pop et valves and operation of said pumps to transfer oil from the cylinder through'the poppet valves to said reservoir to lower said platform; means operable as the platform nears the hangar deck to cause stoppinl of the main pump to slow down the platform and closing of the first named poppet valve; means operable as the platform arrives at the hangar deck to cause stopping ,of the auxiliary pump to stop the platform and closing of the second named poppet .valve; and a pair of relief valves,

an accumulator connected to said cylinder and auxiliary pump for building up the pressure of one for each pump, each relief valve being on the cylinder sideof the pump for which it is provided.

' j r FREDERICK HYMANS.

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