US2417947A - Hydraulically operated elevator - Google Patents

Hydraulically operated elevator Download PDF

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US2417947A
US2417947A US513054A US51305443A US2417947A US 2417947 A US2417947 A US 2417947A US 513054 A US513054 A US 513054A US 51305443 A US51305443 A US 51305443A US 2417947 A US2417947 A US 2417947A
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cylinder
valve
fluid
car
piston
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Charles H Reedy
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MARY B REEDY
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MARY B REEDY
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    • BPERFORMING OPERATIONS; TRANSPORTING
    • B66HOISTING; LIFTING; HAULING
    • B66BELEVATORS; ESCALATORS OR MOVING WALKWAYS
    • B66B1/00Control systems of elevators in general
    • B66B1/02Control systems without regulation, i.e. without retroactive action
    • B66B1/04Control systems without regulation, i.e. without retroactive action hydraulic

Description

March 25, 1947. c. H. REEDY 2,417,947

- HYDRAULICALLY OPERATED ELEVATOR Filed Dec. 6, 1943 INVENTOR. Illa-,1, [FM/a 5 H [FA-50x ATTU RN 5Y8.

Patented Mar. 25, 1947 UNITED STATES PATENT OFFICE Charles H. Reedy, Cincinnati, Ohio, assignor to Mary B. Reedy, Cincinnati, Ohio Application December 6, 1943, Serial No. 513,054

Claims.

My invention relates to improvements in bydraulic elevators and has for its principal objects the provision of a new, improved and simplified mechanism whereby it becomes possible to overcounterbalance the car or cab of the elevator. propel it by power in either direction where power is required, and to coast in either direction where the actual load is such as to permit it. A fundamental object of my invention is the provision of a substantial saving of power in over-ail operation. Another object of my invention is the provision of an apparatus which, while it enables me to gain the advantages which are set forth, is greatly simplified both in its construction and in its operation, is inexpensive to construct and install, and has the minimum number of working parts.

These and other objects of my invention which will be set forth hereinafter or will be apparent to one skilled in the art upon, reading these specifications, I accomplish by that certain construction and arrangement of parts of which I shall now describe an exemplary embodiment. Reference is made to the drawings which in a diagrammatic way show the general features of the aforesaid exemplary embodiment of my in vention, and in which: I

Figure l is a diagrammatic vertica1 section of an elevator installation and the several connections appertaining thereto.

Figure 2 is a sectional view through a valve structure which I may employ.

Figure 3 is another sectional view taken along the line of Figure In the practice of my invention, I provide an elevator structure comprising a cab or car, diagrammatically shown at i, the construction of which is not a limitation upon my invention. This cab or car operates in an elevator shaft broadly indicated at 2, and which may be of any length desired. In the exemplary and diagrammatic showing of my drawing, I have in dicated three floors, respectively l, 5 and 5, in ascending order. at the top of the elevator shaft there is a support 1', which may be a part of the building, or may be supported from the foundation by the guides 88, and which carries a rotatable sheave ii. The car is suspended by one or more cables 9 passing over the sheave 8 and downwardly alongside the elevator shaft so as to pass under sh ave M which is connected in some suitable fashion to the piston rod ll of a. piston 52 operating in an hydraulic cylinder l3. Thence, the cable 9 passes upwardly again to a suitable anchorage 14 at the level of the top of the elevator shaft.

I have thus shown an elevator with a ratio of 1:2. in which the car moves twice as far as the piston in the cylinder. But it will be clear that this forms no limitation upon my invention, and that the principles of it apply equally to ratios of 1:1 or 1:3 and so on, depending upon the cable arrangement chosen.

Also, it should be noted that a number of the principles of my invention may be applied to arrangem nts other than that shown.

The exemplary embodiment, having a cablesuspended car and an off-side power cylinder with the counterweights attached to its piston rod, and a 1:2 ratio of piston and car movements, serves merely to illustrate the application of the principles of my invention to a particular structure.

The hydraulic cylinder 53 may be suitably anchored to a floor or base i5; but its position may be varied. When located alongside the elevator shaft as shown, and coupled to the car in a 1:2 ratio, it will be of such length that the travel of the piston it within it is half the length of the elevator shaft portion through which the car i travels from its lowermost to its uppermost position. It will be noted that the sheave and cable arrangement is such that as the piston l2 descends, the car i is caused to ascend and vice versa, in this embodiment. Suitable counterweights l6 shown fastened to the piston rod ii, guided in suitable guides diagrammatically shown at ll. The car itself will, of course, be guided the elevator shaft by suitable guides The bottom of the cylinder is closed by the anchoring it, and the top of it is closed by a can perforated for the passage of the piston rod 5 i and provided with a packing gland to maintain a fluid-tight connection with the piston rod. Conduits are so connected with the hydraulic cylinder it, both above and below the piston that by controlling the ingress and egress of the operating fluid, the piston may be driven in either direction under power, or permitted to move in either direction under gravitational forces in the system, as will hereinafter be explainec.

In my invention, the efiective value of the counterweight is greater than the weight of the car, though not greater than the weight of the car plus the weight of the maximum load. I preferably counterbalance the weight of the car plus approximately one-half of the weight of the maximum expected load. It will be understood, of course, that the disposition of the cable 9 over and under the respective rotatable sheaves 8 and IE1, and its anchorage as at [4, giving a 1:2 ratio, requires that the actual value of the weight at it: (neglecting, of course, the weight of the piston, piston rod and sheave l), must be twice that of the weight which it is to counterbalance. Where the ratio is changed, or where the car is separately counterbalanced, the ratio of effective weight to actual counterbalance weight will also vary, as will be clear. speaking of the counterbalancing of the car itself, I mean to include the use of a sufficient counterbalance to overcome frictional relationships, where that is desired and practiced.

The result of counterbalancing the car and half of th maximum expected load is that gravity will tend to move the car upwardly if unloaded or loaded with less than one-half the maximum load, whereas gravity will tend to move the car downwardly if loaded with more than one-half the maximum expected load, in the exemplary embodiment. Thus, coasting in either direction is possible depending upon the load conditions and, since my hydraulic cylinder 13 is equipped for power operation in either direction, the driving of the car I in either direction under power is possible. These facts enable me to effect a very substantial power saving over an elevator system in which the car is driven in one direction only by power and is returned solely by gravity in the other direction.

In the practice of my invention, I contemplate the provision of control means which act to permit coasting in the desired direction where coasting is possible, and further act to produce power operation in the desired direction where coasting is impossible. Further, my control means automatically effects the application of power where power is required and further acts, as will hereinafter be explained, to offset differences in fluid displacement above and below the piston l2.

Before these control means are explained, however, I will describe exemplary connections for fluid operations:

I may provide a holder or reservoir 22 for operating fluid. This is connected by a pipe 23 to a pump diagrammatically indicated at 24. This pump may be operated by an electric motor or other prime mover diagrammatically indicated at 25. The delivery part of the pump is connected by a pipe or conduit 26 to my control valve 21. A port in the upper end of my cylinder !3 is also connected to the valve by a conduit 28, and a port near the bottom of the cylinder is connected to it by a conduit '29. The last mentioned conduit (or another port near the bottom of the cylinder i3) is connected by a conduit 30 either back to the conduit 23 or directly to the reservoir 22. The conduit 29 contains a check valve 3| permitting movement of the fluid toward the lower end of the cylinder I3 but not in the opposite direction. The valve 21 is finally connected by a conduit 32 to a reservoir 22.

The precise construction of my valve mechanism may be widely varied. I have illustrated the mechanism in its simplest form in Figures 2 and 3. One essential function of the valve is to connect either the part of the cylinder above the piston 22 or the part below to the source of hydraulic fluid under power, selectively, while connecting the other end of the cylinder to an overflow, exhaust or return, and also to provide It will also be understood that in' an intermediate or neutral position in which the elevator car will be maintained stationary.

In operating from this neutral position to either of the power actuated positions, however, the

' valve functions first to effect a connection between the upper and lower parts of the cylinder for coasting. In the connection so ellected, there will be a check valve to prevent coasting in the wrong direction if the conditions oi" load of the elevator car are such as to produce a tendency to coast in the wrong direction. To this end I provide two passages for hydraulic fluid for coasting, one becoming effective as the valve is actuated in either direction from the intermediate or neutral point to the point or position for power operation.

Yet again, my valve functions in part to compensate during coasting for the difference in fluid displacement in the upper and lower parts of the cylinder due to the presence of the piston rod at one side of the piston.

In its simplest form, my valve may comprise an outer body or housing 33 having a tapered interior bore 34. The outer housing has a port P for the entrance of fluid under pressure through a conduit 25. Opposite this port, there is a port 0 for the outlet of fluid through the conduit 32. Another port T is connected with the top of the cylinder :3 by the conduit 28 as hereinabove described, while another port B is connected by the conduit 29 with the bottom of the cylinder. The housing 33 may be closed by a removable cap 35 at its open end. Within the housing there is a valve plug 35 shaped to fit the tapered bore. This valve plug, in the form shown, has a shaft-like projection 37 at its smaller end which passes through a perforation in. the closed end of the housing, where a compression spring 38, abutting against the housing and against a washer or the lik 39 held by a nut 40 on the end of the projection, may act to keep the plug 36 drawn tightly into the taper.

t the other end of the plug there is a. projection 4| which passes through a perforation in the cap 35 and to which there is non-rotatably attached an operating lever 42 or its equivalent. Where the projections 37 and ti pass throu h the housing or the cap, there may be packing glands, (not shown), as may be desired.

Recesses 43 and 44 are formed in the sides of the valve plug 36. As the valve plug is turned by means of the lever 42, the recess 44 can act either to connect the outlet port 0 with the port 'I or the port B, while the recess 43 acts to connect the port P with the port 13 or with the port T.

In Figure 2 the valve plug is shown in the intermediate position in which none of the ports are interconnected.

Through the valve plug I provide a pair of perforations 45 and 4-3. These perforations or passageways are an ularly related to each other. If the valve plug 35 be turned in a clockwise direction in Figure 2, the passageway 45 will first come into position to connect the port T with the port B, before ports P and 0 become con nected to any other port. Such a position will effect a connection between the upper part of the cylinder l3 and the lower part thereof. This is a connection for coasting. The turning of the valve plug 36 in the clockwise direction in Figure 2 is a movement produced when it is desired that the elevator car ascend. If the car is loaded in such a way that ascent is possible by gravity, when the lower portion of the cylinder is connected to the upper portion, the piston l2 will descend because the counterweight, IE will cause the piston E2 to displace fluid from the lower part of the cylinder through conduit 29, which fluid will enter the upper part of the cylinder through conduit 28.

It will be seen that the displacement of fluid from the lower part of the cylinder l3 below the piston l2 will be greater than the reception of fluid by the upper part of the cylinder during the descent of the piston. This is because of the presence of the piston rod H in the upper part of the cylinder. Some of the hydraulic fluid displaced from the lower part of the cylinder must, therefore, be got rid of, and to accomplish this, I provide a small passageway 41, (Figure 2), between the passageway 45 and the recess 44-. Excess fluid from the lower part of the cylinder l3, entering the valve mechanism through the conduit 29, can thus escape into the outlet port 0. The passageway 35 is proportioned as to size to control the ascent of the elevator car by permitting transfer of fluid from the lower part of the cylinder to the upper part thereof at a rate proportionate to a desired speed of ascent; and the passageway 41 is, of course, very small and is proportioned in diameter to the difference in displacement in the upper and lower parts of the cylinder at the speed oi transfer of fluid through the passageway 45.

At the particular time when the valve in Figure 2 is operated in the clockwise direction to the extent hereinabc-ve described, the conditions of loading of the elevator car may be such, however, as to preclude a coasting ascent, but tend to produce a coasting descent. To prevent coasting in the wrong direction, I include in the passageway 45 a check valve inechanisrd'which, in the form illustrated, includes a ball 48 seating against a suitably shaped portion of the passageway 45, a compression spring 49, and a perforated plug 50 against which the spring abuts. As a consequence, if the operator of the car, desiring to ascend, moves the valve plug (it in the clockwise direction until the passageway lfi connects ports B and T, and if at that time the loading of the car is such as to tend to produce a gravity descent, the check valve will prevent the transfer of fluid from the upper part of the cylinder to the lower part of the cylinder, and the car will remain stationary. Tlriereupon, the operator moves the valve plug iii; still further in the clockwise direction. When so moved, the passageway to will no longer connect ports B and T, but will have moved to a position in which the passageway is closed. However, the recess 44 will now connect ports B and 0, thus effecting an outlet passageway for fluid from the lower part of the cylinder l3 to the overflow or reservoir. At the same time the recess 43 will have been positioned to connect ports P and T so that the upper part of the cylinder is connected to the pump. Assuming the pump to be started into operation at this point, fluid will be fed under power to the cylinder 13 above the piston 52. The piston will descend and the fluid displaced from the lower portion of the cylinder will find its way through conduit 29, the valve, and conduit 32 to the overflow or reservoir. The car will thus be caused to ascend under power. When the de sired ascent has been accomplished, the operator will return the valve to the neutral position shown in Figure 2.

Similarly, when descent is desired, the operator will rotate the valve plug 36 in the counterclockwise direction. As an incident to such rotation, the passageway 46 will first be brought into position to connect ports B and T. If the load conditions are such that descent by gravity is possible, fluid will flow from the upper part of the cylinder to the lower part of the cylinder through the passageway 46 of the valve, which is again so proportioned in size as to control the rate of descent. In order to prevent a coasting ascent when a coasting descent is desired, a check Valve 5! is placed in the passageway 36. It is oppositely directed to the check valve hereinabove described, but may be of the same construction.

During the descent of the car and the consequent ascent of the piston I2, the amount of fluid displaced from the portion of the cylinder above the piston will be less than the amount of fluid required for the lower part of the cylinder, and it will be necessary to admit a quantity of aciditional fluid to the lower part of the cylinder. This is accomplished through the conduit 3-H hereinabove described and the check valve 3|. The extra required fluid will be admitted through this check valve, but the fluid cannot pass in the opposite direction.

If the conditions of load are such that a gravity descent is impossible, the operator still further rotates the valve plug 36 in the counterclockwise direction to a point at which the recess 44 connects ports P and B. The valve is now in a position for a power actuated descent of the car, and assuming the pump 24 to be in operation, fluid under pressure will be fed into the lower part of the cylinder causing the piston [2 to rise, and fluid. from the upper part of the cylinder will be exhausted to the reservoir.

While it is possible separately to start the pump motor, it is preferable to have this occur auto matically as a consequence of the moving of the valve in either direction to a Position for power operation. This may be done in a variety of ways. In the drawings I have diagrammatically illustrated a sliding rod 52 having arms 53 and 54 positioned to be actuated by the lever arm 42 when the switch is thrown in either direction to the power position. Springs 55 and 5E operate to keep the rod 52 in a neutral position when not actuated by the lever arm 42. The contact member 5'! of a switch is fastened to or otherwise adapted to be moved by the rod 52. This contact member may be connected to one of the motor leads as at 58. A pair of cooperating contacts 55 and 63 are located, one on either side of the contact 51, so that actuation of the rod 52 will bring the contact 5'! into engagement either with one or the other of the last mentioned contacts. These last mentioned contacts are electrically connected together and to one of the power leads 6!. The other power lead 62 is connected to the motor 25. It will be understood that this showing is essentially diagrammatic, as is the means to operate the valve 21 from the car I, next to be described.

A cable E3 is anchored as at 64 at the top of the shaft. This cable at the car runs over a sheave at 65, at which point is also pivoted a, bell crank. One arm 66 of the bell crank is the oper ating lever for the elevator. The other arm 61, which is located at an angle to the first arm, bears a sheave 68 over which the cable 63 also passes. The cable, after descending to the bottom of the elevator shaft, passes beneath a sheave 69 and then horizontally, upwardly be neath a sheave Ill, and over a sheave H to a point at which it is connected to the lever arm 42. A continuation of the cable passes over a sheave 72 and downwardly to a suspended weight T3 of sufficient mass to actuate the valve. It will be evident from this construction that the car I can move up and down the elevator shaft without varying the effective length of the cable 63. But if the operating lever 65 be moved in the clocl wise direction, a lesser length of the cable will be taken up over the sheave G3, and the Weight will move the lever arm 4'2 of the valve 2! in the clockwise direction. Eimilarly, if the operating lever be moved counterclockwise, the cable 63 will be effectively shortened, and the lever arm 42 will be pulled a counterclockwise direction.

It will be understood that this mechanism for operating valve is exemplary only of a mechanism which be used. There are many mechanical systems whereby the motion of a control element in the car can be transmitted to the valve in spite of the up and down travel of the car, and the particular mode of transmitting such movement is not limitation on my invention.

I may make provision against the too rapid application of fluid to th cylinder I3, so as to avoid jerks and jolts. This can be accomplished by causing the valve to operate as a gradually acting valve, through expedients known to the art. For example, in the valve of Figure 2, tapering, groove-lilre configurations may be formed on the valve plug as at 74.

Modifications may be made in my invention without departing from the spirit of it. Having thus described my invention, what I claim. as new and desire to secure by Letters Patent is:

1. In a mechanism of the character described an elongated cylinder, a piston therein, a piston rod passing through one end of said cylinder, fluid connections between each end of said cylinder and valve means, a fluid connect-ion between 2 source of fluid under pressure and said valve means, and a connection between an overflow said valve means, said valve means he operable in two directions with two opera tive positions in each direction at progressively reater distances from an intermediate neutral position, and said valve means having separate, cheer-valved passageways acting in the first of said on rative positions in either direction to connect one end of the said. cylinder with the er end thereof, and in the second of said e positions to connect one end of said oylino. with said source of fluid under pressure and the other end of said cylinder with said overflow means, said source of fluid under pressure con rising a pump and a motor, and means act-noble in connection with said valve means at the second of said positions in either direction to energize said motor, and means for compensati for differences in fluid displacement in said cyander on either side of said piston when the ends of said cylinder are connected together.

2. In an apparatus of the character described an elongated cylinder, a piston in said cylinder, a piston rod passing through one end of the cylinder, a source of fluid unde pr ssure, and overflow means and. valve means, said valve means comprising a housing having radial ports therein, an opposite pair of said ports being connected respectively to the two ends of said cylinder, another opposite pair of ports being connected respectively to said source of fluid under pressure and said overflow means, and a valve core in said housing and capable of movement therein, and being so configured that upon movement in 0pposite directions, it will alternatively effect a connection between the last mentioned opposite ports and diiferent ones of the first mentioned opposite ports, said valve core having a pair of separate passageways therethrough so disposed that upon movement of said core in either direction a connection will be effected between said first mentioned opposite ports prior to the effecting the last mentioned connections, said passageways having check valves therein of opposite hand, and one of said passageways having a connecting passageway continuously in communication with said overflow port.

3. In apparatus of the character described an elongated cylinder, a piston in said cylinder, a piston rod passing through one end of the cylinder, a source of fluid under pressure, and overflow means and valve means, said valve means comprising a housing having radial ports therein, opposite pair of said ports being connected respectively to the two ends of said cylinder, another opposite pair of ports being connected respectively to said source of fluid under pressure and said overflow means, and a valve core in said housing and capable of movement therein, and being so configured that upon movement in opposite directions, it will alt: natively effect a connection between the last mentioned opposite ports and diflerent ones of the first mentioned opposite ports, said valve core having a pair of separate passagewaystherethrough so disposed that upon movement of said core in either direction a connection will be effected between said first mentioned opposite ports prior to the effecting of the last mentioned connections, said passageways having check valves therein of opposite hand, one of said passageways having a connecting passageway continuously in communication with said overflow port, said passageways being of relatively small diameter whereby to control the rapidity of flow of fluid between one end of said cylinder and the other.

4. In an apparatus of the character described, an elongated cylinder, a piston in said cylinder, a piston rod passing through one end of the eyl inder, a source of fluid under pressure, and overflow means and valve means, said valve means comprising a housing having radial ports therein, an opposite pair of said ports being connected respectively to the two ends of said cylinder, another opposite pair of ports being connected respectively to said source of fluid under pressure said overflow means, and a valve core in said housing and capable of movement therein, and being so configured that upon movement in opposite directions, it will alternatively effect a connection between the last mentioned opposite ports and diiferent ones of the first mentioned opposite ports, said valve core having a pair of se, ate passageways therethrough so disposed that upon movement of said core in either direction a connection will be effected between said first mentioned opposite ports prior to the effecting of the last mentioned connections, said passageways having check valves therein of opposite hand, and one of said passageways having a connesting passageway continuously in communication, with said overflow port, said passageways being of relatively small diameter whereby to control the rapidity of flow of fluid between one end of said cylinder and the other, and a check valved connection between said overflow and the end of said cylinder remote from said piston rod.

5. In an apparatus of the character described an elongated cylinder, a piston in said cylinder, a piston rod passing through one end ofthe cylinder, a source of fluid under pressure, and overflow means and valve means, said valve means comprising housing having radial ports therein, an opposite pair of said ports being connected respectively to the two ends of said cylinder, another opposite pair of ports being connected respectively to said source of fluid under pressure and said overflow means, and a valve core in said housing and capable of movement therein, and being so configured that upon movement in opposite directions, it will alternatively efiect a connection between the last mentioned opposite ports and different ones of the first mentioned opposite ports, said valve core having a pair of separate passageways therethrough s disposed that upon movement of said core in either direction a connection will be effected between said first mentioned opposite ports prior to the efiecting of the last mentioned connections, said passageways having check valves therein of opposite hand, and one of said passageways having a connecting passageway continuously in communication with said overflow port, said passageways being of relatively small diameter whereby to control the rapidity of fiow of fluid between one end of said cylinder and the other, and a check 10 valved connection between said overflow and the end of said cylinder remote from said piston rod, operating means for said valve core, said source of fluid under pressure comprising a pump and a motor, and switch means for energizing said m0- tor, said switch means arranged to be actuated by said valve operating means upon movement to its final position in either direction,

CHARLES H. REEDY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 503,786 Crosby Aug. 22, 1893 290,660 Bassett Dec. 25, 1883 203,782 Schmidt May 14, 1878 356,999 Hale Feb. 1, 1887 404,528 Foster June 4, 1889 269,994 Bailey Jan. 2, 1883 2,331,790 Nichols Oct. 12, 1943 2,239,139 Allin Apr. 22, 1941 2,120,495 Harris June 14, 1938 1,979,041 Lundskow Oct. 30, 1934 1,974,657 Rodler Sent. 25, 1934 1,300,220 Minard Apr. 8, 1919 448,263 Rymer Mar. 17, 1891 1,200,491 Hall Oct. 10, 1916

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Cited By (18)

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US2627746A (en) * 1948-03-19 1953-02-10 Harry B Fechter Radiator testing tank, including hydraulic lift system
US2639693A (en) * 1949-04-23 1953-05-26 M O Johnston Hydraulic control valve and system
US2796952A (en) * 1954-09-10 1957-06-25 Clarence P Brumby Automobile self-lift elevator
US2906374A (en) * 1957-09-30 1959-09-29 Clarence P Brumby Weight controlled self lift elevator
US2981375A (en) * 1959-08-12 1961-04-25 Toledo Scale Corp Hydraulic elevators
US3001367A (en) * 1956-10-01 1961-09-26 Monarch Elevator & Machine Co Hydraulic elevator control system
US3701528A (en) * 1970-04-20 1972-10-31 Jerry E Ryan Method for simulating the reduction of gravity
US3905496A (en) * 1972-10-04 1975-09-16 William Reeder Unloader elevator with energy means to return the elevator to its loading position
US4807724A (en) * 1988-03-31 1989-02-28 D. L. Martin Company Hydraulic drive system for elevator
US5349142A (en) * 1990-04-25 1994-09-20 Kaisei Kogyo K.K. Energy conservation type hydraulic elevator and speed control method of hydraulic elevator
ES2061366A2 (en) * 1992-08-13 1994-12-01 Sans Jose Antonio Arevalo Hydrostatic elevator
ES2103159A1 (en) * 1992-04-30 1997-08-16 Otis Elevator Co Advanced energy saving hydraulic elevator
US6085872A (en) * 1998-03-25 2000-07-11 Thyssen Elevator Holding Corporation Roped hydraulic elevator
ES2155310A1 (en) * 1996-10-28 2001-05-01 Otis Elevator Co Hydraulic elevator having a counterweight
US20030183459A1 (en) * 2002-03-12 2003-10-02 Orndorff Karl B. Self-balancing synchronization assembly for a hydraulic elevator
US6662905B2 (en) * 2000-05-19 2003-12-16 Carlos Alberto Sors Elevator which counterweight is also the plunger of the propelling fluid dynamic device which produces and controls the movements thereof
WO2007046784A1 (en) * 2005-10-12 2007-04-26 Otis Elevator Company Counterweight with partially imbedded buffer
CN104444718A (en) * 2014-09-30 2015-03-25 三一汽车制造有限公司 Elevator

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US2331790A (en) * 1941-02-25 1943-10-12 Jr Herbert L Nichols Hydraulic control valve

Cited By (22)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2627746A (en) * 1948-03-19 1953-02-10 Harry B Fechter Radiator testing tank, including hydraulic lift system
US2639693A (en) * 1949-04-23 1953-05-26 M O Johnston Hydraulic control valve and system
US2796952A (en) * 1954-09-10 1957-06-25 Clarence P Brumby Automobile self-lift elevator
US3001367A (en) * 1956-10-01 1961-09-26 Monarch Elevator & Machine Co Hydraulic elevator control system
US2906374A (en) * 1957-09-30 1959-09-29 Clarence P Brumby Weight controlled self lift elevator
US2981375A (en) * 1959-08-12 1961-04-25 Toledo Scale Corp Hydraulic elevators
US3701528A (en) * 1970-04-20 1972-10-31 Jerry E Ryan Method for simulating the reduction of gravity
US3905496A (en) * 1972-10-04 1975-09-16 William Reeder Unloader elevator with energy means to return the elevator to its loading position
US4807724A (en) * 1988-03-31 1989-02-28 D. L. Martin Company Hydraulic drive system for elevator
WO1989009179A1 (en) * 1988-03-31 1989-10-05 D.L. Martin Company Hydraulic drive system for elevator
US5349142A (en) * 1990-04-25 1994-09-20 Kaisei Kogyo K.K. Energy conservation type hydraulic elevator and speed control method of hydraulic elevator
ES2103159A1 (en) * 1992-04-30 1997-08-16 Otis Elevator Co Advanced energy saving hydraulic elevator
ES2061366A2 (en) * 1992-08-13 1994-12-01 Sans Jose Antonio Arevalo Hydrostatic elevator
ES2155310A1 (en) * 1996-10-28 2001-05-01 Otis Elevator Co Hydraulic elevator having a counterweight
US6085872A (en) * 1998-03-25 2000-07-11 Thyssen Elevator Holding Corporation Roped hydraulic elevator
US6662905B2 (en) * 2000-05-19 2003-12-16 Carlos Alberto Sors Elevator which counterweight is also the plunger of the propelling fluid dynamic device which produces and controls the movements thereof
US20030183459A1 (en) * 2002-03-12 2003-10-02 Orndorff Karl B. Self-balancing synchronization assembly for a hydraulic elevator
US6659231B2 (en) * 2002-03-12 2003-12-09 Inventio Ag Self-balancing synchronization assembly for a hydraulic elevator
WO2007046784A1 (en) * 2005-10-12 2007-04-26 Otis Elevator Company Counterweight with partially imbedded buffer
US20080257654A1 (en) * 2005-10-12 2008-10-23 Milton-Benoit John M Counterweight With Partially Imbedded Buffer
RU2481262C2 (en) * 2005-10-12 2013-05-10 Отис Элевейтэ Кампэни Elevator system and its counterweight
CN104444718A (en) * 2014-09-30 2015-03-25 三一汽车制造有限公司 Elevator

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