TECHNICAL FIELD

The present invention relates to a counterweighted roped hydraulic lifting system according to the preamble of claim 1 and relates to a method for raising and lowering a lifting member of a counterweighted roped hydraulic lifting system according to claim 12.

The present invention concerns the industry using hydraulic actuators for counterweighted roped hydraulic lifting system in different applications and also concerns the manufacture industry producing such systems, e.g. the construction industry or various elevator providers.

The invention is not limited thereto, but can also be used for replacing current electrical motor arrangements or current hydraulic systems.

BACKGROUND

In order to overcome the problems coupled to raising and lowering of elevators by means of hydraulic actuators there has been suggested several solutions over time.

Current counterweighted roped hydraulic lifting systems are often bulky and require large amount of energy for operation.

In US 5 056 627 is disclosed a hydraulic elevator system using a single hydraulic cylinder with a lever balance for providing a less bulky and heavy arrangement.

Counterweighted roped hydraulic lifting systems of today may also involve major drawbacks in that the hydraulic fluid being used for operating the system is prone to leakage, which may cause a serious environmental hazard, they are bulky etc.

SUM MARY OF THE INVENTION

An object of the present disclosure is to provide a system and a method which seek to mitigate, alleviate, or eliminate one or more of the above-identified deficiencies or other deficiencies in the art and disadvantages singly or in any combination. In this disclosure, a solution to the problem outlined above is proposed. In the proposed solution, a piston rod of a fluid actuator arrangement partly or entirely features a counterweight mass and being configured to balance a lifting member. The above object is obtained by a counterweighted roped hydraulic lifting system arranged to lift and lower a lifting member.

There is an object to provide a counterweighted roped hydraulic lifting system that can be used in high-rise buildings. There is an object to provide a counterweighted roped hydraulic lifting system that does not leak fluid to the environment (i.e. providing that no odour enters the elevator car) at the same time as the counterweighted roped hydraulic lifting system is energy saving.

An object is to make use of at least a first and a second cooperating cylinder, the first cylinder comprising a first piston body, the second cylinder comprising a second piston body, the piston bodies are coupled to a common piston rod, wherein by controlling alternate pressurization of a respective chamber for moving the pistons bodies in an alternating and reciprocating way and by alternately controlling clamping of the respective first and second piston body to the piston rod for propelling the common piston rod, which in turn is coupled to the rope drive.

There is also an object to provide a counterweighted roped hydraulic lifting system of the type defined in the introduction which is environmental friendly and provides clean working environment.

A yet further object is to provide a counterweighted roped hydraulic lifting system that is easy to serve and that involves cost-effective maintenance in service.

This or at least one of said objects has been achieved by a counterweighted roped hydraulic lifting system comprising a rope drive coupled to a lifting member; a hoist arrangement comprising a rope guide pulley arrangement; the rope drive is coupled to a piston rod of a fluid actuator arrangement; a first engagement and disengagement device of a first piston body and a second engagement and disengagement device of a second piston body; the respective first and second engagement and disengagement device is configured to clamp around the piston rod for engagement; the piston rod partly or entirely features a counterweight mass and being configured to balance said lifting member.

In such way there has been achieved a cost-effective counterweighted roped hydraulic lifting system for operation and for manufacture and for maintenance service.

In such way is achieved a cost-effective compact solution with simple valve package wherein standard components can be used. In such way is achieved a less bulky oil reservoir of the fluid supply as the chambers for fluid pressurization are of less volume than current cylinders.

In such way is achieved a counterweighted roped hydraulic lifting system, which is cost-effective to mount by the use of a minor number of valve members and a compact valve arrangement presenting a non-complex valve package with standard components.

Preferably, the fluid supply comprises a valve arrangement coupled to the respective first and second cylinder and optionally to the respective first and second engagement and disengagement device.

Suitably, an upper end of the piston rod is coupled to the rope drive.

Preferably, the piston rod per se entirely or partly features a counterweight mass and being configured to balance the lifting member and lifted loads, wherein the piston rod features a counterweight mass being less than the mass of the lifting member.

In such way is achieved that the elevator can be operated more efficient by offsetting the weight of the lifting member and occupants, so that the arrangement can work energy saving.

In such way the vertical linear movement of the piston rod can be used for a counterweight feature, which may imply dual use in moving the rope drive essentially in linear vertical motion and at the same time use the piston rod as a counterweight being attracted by gravity in linear vertical orientation.

In such way there is achieved a hydraulic elevator comprising a counterweight balance by integrally using (partly and/or entirely) the piston rod as a mass of counterweight. In such way there is provided a counterweighted roped hydraulic lifting system that can accomplish work with only minor amount of input force.

In such way is provided a counterweighted roped hydraulic lifting system that can be put into use in high speed elevators making a speed of 2-4 m/s as required in high-rise buildings.

Preferably, a first extendable and contractible cover is coupled to the first piston end portion and to the first cylinder.

Suitably, the first and second piston body each exposes at least a second piston end portion outside the respective first and second cylinder.

Preferably, a second extendable and contractible cover is coupled to the second piston end portion and to the second cylinder. Suitably, the piston rod extends vertically.

Preferably, the first extendable and contractible cover comprises a hydraulic fluid drain member arranged for collecting overflow hydraulic fluid from the first chamber and/or from the second chamber. Suitably, the hydraulic fluid drain member is configured as a ring-shaped collecting member forming an open section facing the first piston end portion envelope surface.

Preferably, the hydraulic fluid drain member forms a gap between the hydraulic fluid drain member and the first piston end portion envelope surface.

Suitably, the hydraulic fluid drain member is positioned adjacent the first cylinder and comprises a drainage opening.

Suitably, the hydraulic fluid drain means is positioned adjacent an end portion of the cylinder and comprises a drainage opening.

Preferably, an upper end of the piston rod comprises a first coupling member configured to be able to be coupled to the rope drive. Suitably, a lower end of the piston rod comprises a second coupling member configured to be able to be coupled to an additional counterweight.

In such way is achieved that service personal cost-effective can adjust the piston rod weight to the actual mass of the lifting member.

In such way is achieved a counterweighted roped hydraulic lifting system, that can be put into use in current hydraulic lifting systems comprising hydraulic lifting systems.

In such way no expensive modifications of the elevator car or ropes are required.

In such way is achieved that lift capacity of the lifting member is increased.

Preferably, a bearing member is arranged and configured for low friction between the first and the second cylinder and the respective first and second piston end portion. Suitably, the bearing member comprises bronze.

Preferably, the rope drive and the rope guide pulley arrangement being configured as high-geared arrangement. In such way a short and less bulky piston rod can be used.

Preferably, the counterweighted roped hydraulic lifting system comprises a hoist way in which the lifting member and the fluid actuator arrangement and the piston rod are housed.

Suitably, the fluid actuator arrangement is arranged substantially midway in the hoist way.

In such way is achieved an optimal length of the piston rod adapted to the length of the hoist way in vertical direction.

There is thus provided that the hydraulic fluid leaking from the cylinder body directly can be collected in a direct manner and thus prevented from reaching the inner wall of the extendable and contractible cover member.

Preferably, the hydraulic fluid leakage may be unwanted leakage and/or predetermined fluid leakage of hydraulic fluid flow passing the bearing member, e.g. a bronze bearing arranged between a first cylinder end portion and a first piston end portion.

Suitably, the hydraulic fluid leakage may be unwanted leakage and/or predetermined fluid leakage of hydraulic fluid flow passing the bearing member, e.g. a bronze bearing arranged between a second cylinder end portion and a second piston end portion.

Suitably, a bearing member (such as bronze bearing or other bearing comprising bronze alloys and/or tin bronze and/or lead free bronze and/or copper and/or aluminium-bronze and/or carbon graphite or others) being mounted in a first end opening of the cylinder and/or in a second end opening respectively acting as a bearing member arranged between the first cylinder and the first piston body end portions.

Preferably, the counterweighted roped hydraulic lifting system comprises an emergency brake clamping unit configured to be activated by a separate control system coupled to a sensor element, wherein an expandable space of the an emergency brake clamping unit is coupled to a separate fluid supply source, so that in case of emergency, the control system activates the emergency brake clamping unit by pressurizing (via a valve and the separate fluid supply source) the expandable space and a flexibe wall portion formed by expandable space expands radially inward and clamp around the piston rod.

Suitably, the piston rod comprises at least two rod sections, which can be coupled to each other in the longitudinal direction. In such way is achieved that the counterweighted roped hydraulic lifting system can be mounted in a high-rise building in a cost-effective way.

Preferably, the rod sections are configured to be coupled to each other by means of screw members.

Suitably, the lower end of the lowest rod section comprises a coupling member configured to be coupled to an additional counterweight mass.

Preferably, the upper end of the top rod section comprises a coupling member configured to be coupled to the rope drive.

Preferably, each of the first and second piston body exposes at least a first piston end portion outside a respective first and a second cylinder. Suitably, the hoist arrangement comprising a control unit coupled to a valve arrangement configured for operating the lifting member.

Preferably, the piston rod coaxially extends through the first and second piston body and a respective first and second engagement and disengagement device of the respective first and second piston body. Suitably, respective the first and the second engagement and disengagement device are configured to alternately clamp around the piston rod.

Preferably, the respective first and second engagement and disengagement device being configured to clamp around the piston rod for engagement.

Suitably, the piston rod extends through the first and the second piston body, each of which partly being housed in a respective first and second cylinder of a fluid actuator arrangement coupled to a fluid supply via a valve arrangement.

This is also provided by a method for raising and lowering a lifting member of a counterweighted roped hydraulic lifting system comprising: a rope drive coupled to a lifting member; a hoist arrangement comprising a rope guide pulley arrangement; the rope drive is coupled to a piston rod of a fluid actuator arrangement comprising a first and second cylinder; a first engagement and disengagement device of a first piston body of the first cylinder and a second engagement and disengagement device of a second piston body of the second cylinder; the respective first and second engagement and disengagement device is configured to clamp around the piston rod for engagement; the piston rod partly or entirely features a counterweight mass and being configured to balance said lifting member; wherein the method comprises the steps of; alternately regulating fluid flow from the fluid supply to the respective first and second cylinder and to the respective first and second engagement and disengagement device for moving the piston rod downward; and alternately regulating fluid flow from a fluid supply to the respective first and second cylinder and to the respective first and second engagement and disengagement device for moving the piston rod upward.

Preferably, the method further comprising the steps of providing a first actual piston rod/fluid actuator arrangement feature value to the control unit; comparing the first actual piston rod/fluid actuator arrangement feature value with a first desired piston rod/fluid actuator arrangement feature value; repeating the preceding steps until the first actual piston rod/fluid actuator arrangement feature value corresponds with the first desired piston rod/fluid actuator arrangement feature value.

Suitably, the step of alternately regulating fluid flow from the fluid supply to the respective first and second cylinder and to the respective first and second engagement and disengagement device for moving the piston rod upward partly or entirely is performed by the aid of gravity attracting the lifting member.

There is also provided a lifting member of a counterweighted roped hydraulic lifting system comprising a rope drive coupled to the lifting member and a rope guide pulley arrangement of a hoist arrangement; the rope drive is coupled to a piston rod extending through a first and second piston body, each of which partly being housed in a respective first and second cylinder of a fluid actuator arrangement coupled to a fluid supply via a valve arrangement and which exposing at least a first piston end portion outside the respective first and second cylinder; the hoist arrangement comprising a control unit coupled to the valve arrangement for operating the lifting member; the piston rod coaxially extends through the first and second piston body and a respective first and second engagement and disengagement device of the respective first and second piston body configured to alternately clamp around the piston rod; the piston rod partly or entirely features a counterweight mass and being configured to balance said lifting member, wherein the fluid actuator arrangement is configured for moving the lifting member by means of a method for raising and lowering a lifting member of a counterweighted roped hydraulic lifting system comprising: a rope drive coupled to a lifting member; a hoist arrangement comprising a rope guide pulley arrangement; the rope drive is coupled to a piston rod of a fluid actuator arrangement comprising a first and second cylinder; a first engagement and disengagement device of a first piston body of the first cylinder and a second engagement and disengagement device of a second piston body of the second cylinder; the respective first and second engagement and disengagement device is configured to clamp around the piston rod for engagement; the piston rod partly or entirely features a

counterweight mass and being configured to balance said lifting member; wherein the method comprises the steps of; alternately regulating fluid flow from the fluid supply to the respective first and second cylinder and to the respective first and second engagement and disengagement device for moving the piston rod downward; and alternately regulating fluid flow from a fluid supply to the respective first and second cylinder and to the respective first and second engagement and disengagement device for moving the piston rod upward.

Alternatively, the fluid actuator arrangement is configured for moving the lifting member by means of additional steps of; providing a first actual piston rod/fluid actuator arrangement feature value to the control unit; comparing the first actual piston rod/fluid actuator arrangement feature value with a desired piston rod/fluid actuator arrangement feature value; repeating the preceding steps until the first actual piston rod/fluid actuator arrangement feature value corresponds with the first desired piston rod/fluid actuator arrangement feature value.

Alternatively, the fluid actuator arrangement is configured for moving the lifting member by means of additional steps of; providing wherein the step of alternately regulating fluid flow from the fluid supply to the respective first and second cylinder and to the respective first and second engagement and disengagement device for moving the piston rod upward partly or entirely is performed by the aid of gravity attracting the lifting member.

There is also provided a data medium storing program adapted for moving a lifting member according to claim 15 , wherein said data medium storing program comprises a program code stored on a medium, which is readable on a computer, for causing a control unit to perform the method steps of alternately regulating fluid flow from the fluid supply to the respective first and second cylinder and to the respective first and second engagement and disengagement device for moving the piston rod downward; and alternately regulating fluid flow from the fluid supply to the respective first and second cylinder and to the respective first and second engagement and disengagement device for moving the piston rod upward.

There is also provided a data medium storing program product comprising a program code stored on a medium, which is readable on a computer, for performing the method steps according to any of claims 12 to 14, when a data medium storing program according to claim 16 is run on a control unit. Suitably, the method further comprises the steps of moving the piston rod a first distance by controlling a first valve member to pressurize the first chamber of the first cylinder and by controlling a second valve member to pressurize the first expandable cavity for clamping action on the piston rod; and moving the piston rod a second distance by controlling the first valve member to pressurize the third chamber of the second cylinder and by controlling the second valve member to pressurize the second expandable cavity for clamping action on the piston rod; disengage the piston rod engagement and disengagement device of the first cylinder from the piston rod by pressurizing the first cylinder chamber of the first cylinder with a second pressure being lower than the first pressure; and repeating the steps for moving the piston rod further distance.

Preferably, the method further comprises the steps of moving the piston rod a first distance by controlling the valve arrangement to pressurize the first chamber with a first pressure and, via a channel system of the first piston body, simultaneously pressurize a first expandable cavity for expanding a first flexible piston inner wall portion providing a radial clamping force onto the piston rod; and moving the piston rod a second distance, by controlling the valve arrangement to pressurize the third chamber of the second cylinder with the first pressure and simultaneously pressurize a second expandable cavity for expanding a second flexible piston inner wall portion providing a radial clamping force onto the piston rod and simultaneously or afterwards controlling the valve arrangement to disengage each piston body from the piston rod by pressurizing the chambers with a second pressure being lower than the first pressure; and repeating the steps for moving the piston rod further distance.

Preferably, the fluid actuator arrangement comprises a first and second cylinder in fluid

communication with a fluid supply, wherein a first piston body of the first cylinder comprises a first rod engagement and disengagement device, a second piston body of the second cylinder comprises a second rod engagement and disengagement device, wherein the first piston body and the second piston body being configured to be arranged around a common piston rod.

Preferably, the first engagement and disengagement device comprises a first expandable cavity coupled to the fluid supply. Suitably, the second engagement and disengagement device comprises a second expandable cavity coupled to the fluid supply.

Preferably, the first piston body divides the first cylinder into a first and second chamber, at least one of which being coupled to a fluid supply via a valve arrangement.

Suitably, the second piston body divides the second cylinder into a third and fourth chamber, at least one of which being coupled to a fluid supply via a valve arrangement. Preferably, the arrangement comprises a control unit for controlling engagement and disengagement of the respective first and second engagement and disengagement device.

Suitably, the control unit controls the valve arrangement to pressurize respective first, second, third and fourth chamber and pressurize the respective first and second engagement and disengagement device in regard to detected motion and/or force/load features, detected by sensor members associated with the respective first and second piston body.

Preferably, the first engagement and disengagement device is controlled by a first pressure of the pressurized first chamber, wherein said first pressure also acts onto a first expandable inner wall (membrane) formed by a first expandable cavity of the first engagement and disengagement device of the first piston body, which first expandable inner wall thereby expands in radial direction inward toward the envelope surface of the piston rod and clamps around the piston rod, wherein the pressurized first chamber provides a motion of the first piston body thereby propelling the piston rod.

Suitably, the second engagement and disengagement device is controlled by the first pressure of the pressurized third chamber, wherein said first pressure also acts onto a second expandable inner wall (membrane) formed by a second expandable cavity of the second engagement and disengagement device of the second piston body, which second expandable inner wall thereby expands in radial direction inward toward the envelope surface of the piston rod and clamps around the piston rod, wherein the pressurized third chamber provides a motion of the second piston body thereby propelling the piston rod.

Suitably, the first expandable cavity is positioned in the first piston body and oriented coaxially and is parallel with the first expandable inner wall and at a distance from the piston rod envelope surface (i.e. coaxial with the piston rod).

Suitably, a first pressure of the pressurized first chamber is provided to act onto a piston force area of the first piston body for moving the first piston body in the axial direction relative the first cylinder.

Preferably, a first pressure of the pressurized third chamber is provided to act onto a piston force area of the second piston body for moving the second piston body in the axial direction relative the second cylinder. The respective engagement of the respective first and second engagement and disengagement device of the respective first and second piston body to the piston rod is performed alternately. In such way is achieved an optimal and secure functionality providing accurate performance of the lifting member.

The speed and force of the piston rod relative the first and second cylinder can thus be controlled in an efficient way by varying the pressure of the pressurized fluid in discrete steps controlled by the control unit.

Preferably, a first coupling of a first extendable and contractible cover member is provided for coupling of the first extendable and contractible cover member to the first cylinder (preferably to one end of the first cylinder).

Suitably, a second coupling of the first extendable and contractible cover member is provided for coupling of the first extendable and contractible cover member to a first piston end portion of the first piston body.

Preferably, a third coupling of a second extendable and contractible cover member is provided for coupling of the second extendable and contractible cover member to the first cylinder (preferably to the other end of the first cylinder). Suitably, a fourth coupling of the second extendable and contractible cover member is provided for coupling of the second extendable and contractible cover member to a second piston end portion of the first piston body.

Preferably, a fifth coupling of a third extendable and contractible cover member is provided for coupling of the third extendable and contractible cover member to the second cylinder (preferably to one end of the second cylinder).

Suitably, a sixth coupling of the third extendable and contractible cover member is provided for coupling of the third extendable and contractible cover member to a first piston end portion of the second piston body.

Preferably, a seventh coupling of a fourth extendable and contractible cover member is provided for coupling of the fourth extendable and contractible cover member to the second cylinder (preferably to the other end of the second cylinder).

Suitably, an eight coupling of the second extendable and contractible cover member is provided for coupling of the eight extendable and contractible cover member to a second piston end portion of the second piston body. Preferably, the first, second, third and/or fourth coupling comprises one or more O-rings, clamping rings, duplex clamping rings and/or combinations thereof, which encircle or otherwise are mounted to the end region of the respective extendable and contractible cover member in contact with the first cylinder and the first piston body end portion. Suitably, such coupling may be performed via inclusion of metal rings, plastic rings, or the like.

Preferably, the hydraulic fluid drain member may be designed with a cup-shaped form, trough- shaped or shaped in any suitable way for collecting hydraulic fluid entering the interior of the respective extendable and contractible cover member and being fed from the respective chamber.

Suitably, the hydraulic fluid drain member is coupled to a hydraulic fluid collecting tank positioned outside the extendable and contractible cover member.

Preferably, the method comprises the step of providing a second pressure to all chambers of the fluid actuator arrangement to disengage the piston rod engagement and disengagement devices from the piston rod.

Preferably, a control unit is associated with a sensor device of the counterweighted roped hydraulic lifting system for determining a first actual piston rod/fluid actuator arrangement feature value and/or a first cylinder-piston body feature value.

Suitably, the control unit is coupled to the valve arrangement for regulating fluid flow.

Preferably, a lower piston rod end coupling of the piston rod is configured to provide a coupling between a counter weight member and the piston rod. Suitably, an upper piston rod end coupling of the piston rod is configured to provide a coupling between the rope guide pulley arrangement and the piston rod.

Suitably, the counterweighted roped hydraulic lifting system comprises an energy recovery arrangement for recovering energy during the lowering of the lifting member.

Preferably, the counterweighted roped hydraulic lifting system comprises an emergency brake clamping unit configured to be activated by a separate control system and a separate fluid supply.

Suitably, the energy recovery arrangement comprises a fluid actuator arrangement configured to be used for moving a piston rod.

Preferably, the energy recovery arrangement comprises a pump device including a pump inlet coupling arrangement and a pump outlet coupling arrangement. Suitably, the pump device is configured to supply fluid to the fluid actuator via the pump outlet coupling arrangement.

Preferably, the energy recovery arrangement is configured for fluid communication between the fluid actuator arrangement and the pump device via a valve arrangement. Preferably, a first fluid supply line arrangement is arranged between the second chamber and the pump device via the valve arrangement.

Suitably, a second fluid supply line arrangement is arranged between the fourth chamber and the pump device via the valve arrangement.

Preferably, the counterweighted roped hydraulic lifting system comprises an energy recovery arrangement for regenerate energy during the lowering of the lifting member.

Suitably, the energy recovery arrangement comprises a fluid actuator arrangement used for moving the piston rod.

Preferably, the energy recovery arrangement comprises an electric motor/generator device coupled to the fluid supply. Suitably, the electric motor/generator device is coupled to a pump arrangement configured to feed fluid to the fluid actuator arrangement for raising the lifting member.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described by way of examples with references to the accompanying schematic drawings, of which: Figs, la and lb illustrate a counterweighted roped hydraulic lifting system according to a first example;

Fig. 2 illustrates a fluid actuator arrangement of a counterweighted roped hydraulic lifting system according to a second example;

Figs. 3a and 3b illustrate a fluid actuator arrangement of a counterweighted roped hydraulic lifting system according to a third example;

Figs. 4a and 4b illustrate a fluid actuator arrangement of a counterweighted roped hydraulic lifting system according to further examples; Fig. 5 illustrates a fluid actuator arrangement of a counterweighted roped hydraulic lifting system according to a fifth example;

Figs. 6a and 6b illustrate alternative flowcharts showing exemplary methods for raising and lowering a lifting member of a counterweighted roped hydraulic lifting system; and Fig. 7 illustrates a control unit according to different embodiments of the invention.

DETAILED DESCRIPTION

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings, wherein for the sake of clarity and understanding of the invention some details of no importance may be deleted from the drawings. Figs, la and lb illustrate a counterweighted roped hydraulic lifting system 101 according to a first example. The counterweighted roped hydraulic lifting system 101 comprises a hoist arrangement 103 including a rope guide pulley arrangement 105 and is housed in a hoist way 107. Fig. la shows a counterweighted roped hydraulic lifting system 101 comprising a rope drive 109. The rope drive 109 comprises a single rope having a first 111 and a second 113 end. The first end 111 is coupled to a lifting member 115, such as an elevator car, and the second end 113 is coupled to an upper end 116 of a piston rod 117 of a fluid actuator arrangement 119. The fluid actuator arrangement 119 is fasten to the hoist way 107 in a middle section of the hoist way 107 seen in the vertical direction of the overall length of the hoist way 107. The rope guide pulley arrangement 105 comprises a first 121 and a second 123 guide pulley serving as a gear mechanism. The first guide pulley 121 is coupled to the upper end 116 of the piston rod 117 and is configured to move together with the piston rod 117. The second guide pulley 123 is coupled to an upper portion 125 of the hoist way 107 and positioned stationary relative the piston rod 117. The second end 113 of the single rope (rope drive 109) is coupled to the piston rod 117 upper end 116 via the first guide pulley 121 and to the upper portion 125. The piston rod 117 extends through a first and second piston body (see for example Fig. 2), each of which partly being housed in a respective first and second cylinder (see for example Fig. 2) of the fluid actuator arrangement. The respective first and second cylinders of the fluid actuator arrangement 119 are coupled to a fluid supply 127 via a line arrangement 129. A valve arrangement 131 is configured to control the piston rod 117 driving performance by means of the respective first and second piston body and is arranged between the fluid supply 127 and the fluid actuator arrangement 119. A control unit 133 is configured to control the valve arrangement 131 and is coupled to the valve arrangement 131 for operating the lifting member 115 by means of the fluid actuator arrangement 119. The piston rod 117 coaxially extends through the first and second piston body (see for example Fig. 2). A first and second engagement and disengagement device (see for example Fig. 2) of the respective first and second piston body being configured to alternately clamp around the piston rod 117 for driving the piston rod 117 as being further explained below. A lower end 118 of the piston rod 117 is coupled to a counter weight memberl35 featuring a first counterweight mass. The piston rod 117 per se features a second counter weight mass. The first and second counterweight mass together feature a total counterweight mass for balancing the mass of the lifting member 115. In Fig. la is shown the raising of the lifting member 115 according to a first arrow Al by moving the piston rod 117 downward according to arrow A2. By means of the first 121 and the second 123 guide pulley (serving as a gear mechanism) the speed of the lifting member 115 will be twice that of the piston rod 117. In Fig. lb is shown that the fluid actuator arrangement 119 has moved the piston rod 117 downward a first distance Dl, wherein the lifting member 115 has been moved a second distance D2.

Fig. 2 illustrates a fluid actuator arrangement 219 of a counterweighted roped hydraulic lifting system 201 according to a second example. A first actuating unit 24 comprises a first piston body 245' dividing a first cylinder 247' into a first CI and second C2 chamber, both of which being coupled to a fluid supply 227 via a valve arrangement 231. The first piston body 245' is designed with a first PI and second P2 protruding portion longitudinally protruding from a respective piston force area of the piston body and along the elongated orientation of a piston rod 217. The first PI and second P2 protruding portion each comprises a respective first 25 and second piston end portion 253'. The first piston body 245' comprises a first engagement and disengagement device 255' comprising a first expandable cavity 256'. The first expandable cavity 256' is coupled to the fluid supply 227 via the respective first CI and second chamber C2 for e.g. alternately fluid communication. The first piston body 245' comprises a first expandable inner wall formed by the first expandable cavity 256' and is configured to expand in a direction radially inward toward the piston rod 217 envelope surface for providing a clamping action upon pressurization of the first expandable cavity 256'. A second actuating unit 241" comprises a second piston body 245" dividing a second cylinder 247" into a third C3 and fourth chamber C4, both of which being coupled to the fluid supply 227 via the valve arrangement 231. The second piston body 245" is designed with a third P3 and a fourth P4 protruding portion longitudinally protruding from a respective piston force area of the piston body and along the elongation of the piston rod 217. The third P3 and fourth P4 protruding portion each comprises a respective third 251" and fourth piston end portion 253". The second piston body 245" comprises a second engagement and disengagement device 255" comprising a second expandable cavity 256". The second expandable cavity 256" is coupled to the fluid supply 227 via the respective third C3 and fourth chamber C4. The second piston body 245" comprises a second expandable inner wall formed by the second expandable cavity 256" and is configured to expand in a direction radially inward toward the piston rod 217 envelope surface for providing a clamping action upon

pressurization of the second expandable cavity 256". The first 247' and the second cylinder 247" are rigidly coupled to each other in tandem in axial direction along the prolongation of the piston rod 217.

A first extendable and contractible cover 26 is coupled to the first piston end portion 25 and to the first cylinder 247' (a first end thereof). A second extendable and contractible cover 262' is coupled to the second piston end portion 253' and to the first cylinder 247' (a second end thereof). A third extendable and contractible cover 261" is coupled to the third piston end portion 251" and to the second cylinder 247" (a first end thereof). A fourth extendable and contractible cover 262" is coupled to the fourth piston end portion 253" and to the second cylinder 247" (a second end thereof). Each of the first 26 , second 262', third 261" and fourth 262" extendable and contractible cover comprises a respective hydraulic fluid drain member 270 arranged for collecting overflow hydraulic fluid from a predetermined leakage of hydraulic fluid from the respective first CI, second C2, third C3 and fourth C4 chamber. The overflow hydraulic fluid is due to pre-determined leakage between the first cylinder 247' and the first piston body 245' leaking from the respective first CI and second C2 chamber. The overflow hydraulic fluid is also due to pre-determined leakage between the second cylinder 247" and the second piston body 245" leaking from the respective third C3 and fourth C4 chamber. Such overflow hydraulic flow leakage promotes so called hydrodynamic bearing functionality providing a viscous friction between the first cylinder 247' and the first piston body 245' (and correspondingly between the second cylinder and the second piston body). This is due when the first piston body 245' is moved relative the first cylinder 247' by pressurization of the respective first CI and second chamber C2 and the hydraulic fluid is set to leak from the respective first CI and second C2 chamber to the respective first and second extendable and contractible cover 261', 262'. A first non-contact and/or contact bearing 280' is arranged in a first through bore of the first end of the first cylinder 247'. A second non-contact and/or contact bearing 280" is arranged in a second through bore of the second end of the first cylinder 247'. A third non-contact and/or contact bearing (not shown) is arranged in a third through bore of the first end of the second cylinder 247". A fourth non-contact and/or contact bearing (not shown) is arranged in a fourth through bore of the second end of the second cylinder 247". The hydraulic fluid overflows from the respective first CI, second C2, third C3 and fourth C4 chamber into the respective first 26 , second 262', third 261" and fourth 262" extendable and contractible cover. The respective first 255' and second 255" engagement and disengagement device being controlled by the pressurized fluid fed from the highest pressurized chamber. The pressurizing of the respective first 256' and second 256" expandable cavity may be made via a channel system arranged in the respective piston body or via an external channel system (not shown). A fluid line system L is coupled to the expandable cavities via valve means V (coupled to control unit 233) directly via the respective exterior portion of the respective piston bodies.

The engagement of the first piston body 245' to the piston rod 217 and a pressurization of e.g. the second chamber C2 for moving the first piston body 245' downward will provide the raising of the lifting member (e.g. reference 115 in Fig. la) with a distance corresponding twice the length of a stroke length of the first piston body 245'. By alternately clamping of the respective first 245' and second 245" piston body to the piston rod 217 and by alternately pressurizing the first CI, second C2, third C3, fourth C4 chambers in an overlapping manner there is achieved a smooth motion of the piston rod 217. A first position sensor SI is arranged on the first cylinder 247' for detecting a relative motion of the first piston body 245'. The first position sensor SI is coupled to the control unit 233. The control unit 233 is coupled to and controls the valve arrangement 231 for controlling the movement of the piston rod 217. A second position sensor S2 is arranged on the second cylinder 247" for detecting a relative motion of the second piston body 245". The second position sensor S2 is coupled to the control unit 233. The control unit 233 is coupled to and controls the valve arrangement 231 for controlling the movement of the piston rod 217. The control unit 233 controls the valve arrangement 231 to pressurize respective first CI, second C2, third C3, fourth C4 chamber and the first and second engagement and disengagement device 255, 255" in regard to detected piston body motion features by the first and second position sensors SI, S2. This procedure is repeated for continuously moving the lifting member. An end switch sensor S3 is arranged to the piston rod 217 and is coupled to the control unit 233 for detection of a piston rod position relative the hoist way. The hydraulic fluid drain member 270 is coupled to a hydraulic fluid collecting tank 240 positioned outside the extendable and contractible cover member.

Figs. 3a and 3b illustrate a fluid actuator arrangement 319 of a counterweighted roped hydraulic lifting system according to a third example. The fluid actuator arrangement 319 may be added with a piston rod clamping unit (not shown) for step-wise holding the piston rod or may be added with at least one co-operating fluid actuator arrangement similar to that shown in Fig. 3a. The fluid actuator arrangement 319 comprises first 351 and second 353 piston end portions of a first piston body 345, both of which project outside (with a part depending of the stroke state of the piston body in the cylinder) a first cylinder 347 through which the first piston body 345 is slidingly arranged. The first piston body 345 comprises an enlarged mid-section M forming opposite piston force areas FA dividing the first cylinder 347 interior into a first CI and a second chamber C2 and comprising a channel system 390 configured for fluid communication with a first clamping membrane 355 of the first piston body 345. The exterior portions (first 351 and second 353 piston end portions) of the first piston body 345 extending from the first cylinder 347 are sealingly covered by an upper 362 and a lower 361 boot. A first fluid collecting hose HI is connected to the lower boot 361 for collecting overflow hydraulic oil fed from the first chamber CI. A second fluid collecting hose H2 is connected to the upper boot 362 for collecting overflow hydraulic oil fed from the second chamber C2. A bearing member 399 is arranged and configured for low friction between the first and the second cylinder and the respective at least first piston end portion and is configured to leak a predetermined amount of hydraulic fluid to the boot from the chamber CI for providing a viscous friction bearing. The boots comprises end plates 376, each of which being sealingly coupled to the piston body outer ends and leaving passage for the piston rod. Fig. 3b shows an example of a respective hydraulic fluid drain member 377 (coupled to the respective upper and lower boot) comprising a ring-shaped hydraulic fluid collecting ring 390 constituting a part of the extendable and contractible cover (upper 362 and lower 361 boot) shown in Fig. 3a. The ring- shaped hydraulic fluid collecting ring 390 is configured for vertically oriented fluid actuator arrangements and comprises an outer peripher ring wall portion 391 connected to a first 392 and a second 393 flange wall portion. A first ring-shaped hydraulic fluid collecting ring 390' is mounted around the first piston end portion 351 of the first piston body 345 in such way that there is provided a gap G between the first piston end portion 351 envelope surface and the first 392 and a second 393 flange wall portion. A first outlet port 394 is arranged at a lower portion of the outer peripher ring wall portion 391 and is coupled to a fluid collecting tank T via the first collecting hose HI. The first ring-shaped hydraulic fluid collecting ring 390' forms an open section facing the first piston end portion 351. The respective first 392 and second 393 flange wall portion forms a first open slot extending in circumferential direction around the first piston end portion 351. A second ring-shaped hydraulic fluid collecting ring 390" is mounted around the second piston end portion 353 of the first piston body 345 in such way that there is provided a gap G between the second piston end portion 353 envelope surface and the first 392 and a second 393 flange wall portion. A second outlet port

394 is arranged at a lower portion of the outer peripher ring wall portion 391 which is coupled to the fluid collecting tank T via the second collecting hose H2. The second ring-shaped hydraulic fluid collecting ring 390" forms an open section facing the second piston end portion 353. The respective first 392 and second 393 flange wall portion form an open slot extending in circumferential direction around the second piston end portion 353. Opposite the outlet port 394 of each ring-shaped hydraulic fluid collecting ring there is provided a gas port 395. The gas ports of the respective ring- shaped hydraulic fluid collecting ring are coupled to each other via a pressure balancing hose H3 for smooth and free alternately extending and contracting of the extendable and contractible covers during operation of the fluid actuator arrangement 319. Fig. 4a illustrates a fluid actuator arrangement 419 of a counterweighted roped hydraulic lifting system 401 according to a fourth example. The counterweighted roped hydraulic lifting system 401 in Fig. 4a comprises an emergency brake clamping unit 470 configured to be activated by a separate control system 433' coupled to a sensor S and a separate fluid supply 427'. A rope guide pulley arrangement 405 of the counterweighted roped hydraulic lifting system 401 comprises four guide pulleys 421', 421", 42 ", 421"" serving as a gear mechanism. A lower piston rod end coupling 430 of the piston rod 417 is configured to provide a coupling between a counter weight 435 and the piston rod 417. An upper piston rod end coupling 431 of the piston rod 417 is configured to provide a coupling between the first guide pulley 42 of the rope guide pulley arrangement 405 and the piston rod 417.

Fig. 4b illustrates a fluid actuator arrangement 819 of a counterweighted roped hydraulic lifting system 801 according to a further example. The lifting member according to this embodiment constitutes a lifting hook 815. In this example the piston rod 817 per se entirely features a counterweight mass and being configured to balance the lifting hook 815 and lifted loads, i.e. the piston rod 817 features a counterweight mass being slighter less than the mass of the lifting member.

Fig. 5 illustrates a fluid actuator arrangement 519 of a counterweighted roped hydraulic lifting system 501 according to a fifth example. The counterweighted roped hydraulic lifting system 501 comprises an energy recovery arrangement 580 for recovering energy during the lowering of the lifting member (not shown). The energy recovery arrangement 580 comprises the fluid actuator arrangement 519 used for moving a piston rod 517 coupled to the lifting member via a rope drive. A fluid supply 527 is coupled to an electric motor/generator device MG.

The electric motor/generator MG is configured to supply fluid to the fluid actuator arrangement 519 for raising the lifting member and to regenerate energy when lowering the lifting member. The energy recovery arrangement 580 is configured for fluid communication between the fluid actuator arrangement 519 and the fluid supply 527 via a valve arrangement 531.

A first piston body 545' divides a first cylinder 547' into a first and second chamber CI, C2 each being coupled to the fluid supply 527 via the valve arrangement 531. A second piston body 545" divides a second cylinder 547" into a third C3 and fourth C4 chamber each being coupled to the fluid supply 527 via the valve arrangement 531. A first fluid supply line 586 arrangement is arranged between the second chamber C2 and the fluid supply 527 comprising the electric motor/generator MG via the valve arrangement 531. A second fluid supply line 587 arrangement is arranged between the fourth chamber C4 and the fluid supply 527 comprising the electric motor/generator MG via the valve arrangement 531.

A respective engagement and disengagement device 555', 555" of the respective first and second piston body 545', 545" alternately clamps around the piston rod 517 for moving the piston rod 517 downward by pressurizing the second and fourth cylinder chamber C2, C4 alternately by means of the fluid supply comprising the electric motor/generator MG in a first mode acting as a motor for feeding fluid to the cylinder chambers. The energy recovery arrangement 580 is regenerate energy during raising of the piston rod 517, when the lifting member is controlled to be lowered, whereby the respective second C2 and fourth C4 chamber by means of upward moving of the first 545' and second 545" piston body will force excess fluid out from the respective second C2 and fourth C4 cylinder chamber and further to the electric motor/generator MG in a second mode acting as a generator.

A control unit 533 is configurated to control the valve arrangement 531 is configured to receive actual process signals of the actual operation of the fluid actuator arrangement 519 and the piston rod 517. Sensors SI and S2 are coupled to the control unit 533. An extendable and contractible cover 561 is arranged sealingly in contact with the respective first and second piston body 545', 545" outer envelope surface at outer piston ends for collecting a predetermined volume of fluid overflow from the chambers CI, C2, C3, C4 to the extendable and contractible cover 561 (via bearing members serving as so called hydrodynamic bearings). A hydraulic fluid drain member 570 is coupled to a hydraulic fluid collecting tank T positioned outside the extendable and contractible cover member 561. The hydraulic fluid drain member 570 is configured for collecting overflow hydraulic fluid.

Figs. 6a-6b illustrate flowcharts showing exemplary methods for controlling the raising and lowering a lifting member of a counterweighted roped hydraulic lifting system according to different aspects. Fig. 6a illustrates a method for raising and lowering a lifting member of a counterweighted roped hydraulic lifting system comprising; a rope drive coupled to the lifting member and a rope guide pulley arrangement of a hoist arrangement; the rope drive is coupled to a piston rod extending through a first and second piston body, each of which partly being housed in a respective first and second cylinder of a fluid actuator arrangement coupled to a fluid supply via a valve arrangement and each of which exposing at least a first piston end portion outside the respective first and second cylinder; the hoist arrangement comprising a control unit coupled to the valve arrangement for operating the lifting member; a piston rod coaxially extends through the first and second piston body and a respective first and second engagement and disengagement device of the respective first and second piston body configured to alternately clamp around the piston rod; the piston rod partly or entirely features a counterweight mass and being configured to balance said lifting member. The method shown in Fig. 6a illustrates a first step 601 comprising the start of the method. A second step 602 illustrates the operating of the counterweighted roped hydraulic lifting system. A third step 603 illustrates a stop of the method. The second step 602 may comprise the steps of; alternately regulating fluid flow from the fluid supply to the respective first and second cylinder and to the respective first and second engagement and disengagement device for moving the piston rod downward; and alternately regulating fluid flow from the fluid supply to the respective first and second cylinder and to the respective first and second engagement and disengagement device for moving the piston rod upward. Fig. 6b illustrates a further example of the method. Step 1001 illustrates start of the method. Step 1002 shows providing a first actual piston rod/fluid actuator arrangement feature value to the control unit. Step 1003 shows comparing the first actual piston rod/fluid actuator arrangement feature value with a first desired piston rod feature value Step 1004 shows repeating the preceding steps until the first actual piston rod/fluid actuator arrangement feature value corresponds with the first desired piston rod/fluid actuator arrangement feature value. Step 1005 shows alternately regulating fluid flow from the fluid supply to the respective first and second cylinder and to the respective first and second engagement and disengagement device for moving the piston rod upward partly or entirely is performed by the aid of gravity attracting the lifting member. In Step 1006 the method is fulfilled and stopped.

Fig. 7 illustrates a CPU device 700 according to different embodiments of the invention. A control unit of the counterweighted roped hydraulic lifting system may have any of reference signs 133, 233, 433, 533 above, which control unit comprises the CPU device 700 of a computer. The CPU device 700 comprises a non-volatile memory NVM 720, which is a computer memory that can retain stored information even when the computer is not powered. The CPU device 700 further comprises a processing unit 710 and a read/write memory 750. The NVM 720 comprises a first memory unit 730. A computer program (which can be of any type suitable for any operational data) is stored in the first memory unit 730 for controlling the functionality of the CPU device 700. Furthermore, the CPU device 700 comprises a bus controller (not shown), a serial communication port (not shown) providing a physical interface, through which information transfers separately in two directions. The CPU device 700 may comprise any suitable type of I/O module (not shown) providing input/output signal transfer, an A/D converter (not shown) for converting continuously varying signals from detectors (not shown) arranged to the fluid actuator arrangement and from other monitoring units (not shown) of the fluid actuator arrangement into binary code suitable for the computer.

The CPU device 700 also comprises an input/output unit (not shown) for adaption to time and date. The CPU device 700 also comprises an event counter (not shown) for counting the number of event multiples that occur from independent events in operation of the fluid actuator arrangement.

Furthermore, the CPU device 700 includes interrupt units (not shown) associated with the computer for providing a multi-tasking performance and real time computing for operating a first and second mode of operation as described above. The NVM 720 also includes a second memory unit 740 for external controlled operation.

A data medium storing program P, comprising program routines, is adapted for controlling the valve arrangement and is provided for operating the CPU device 700 for performing the method described. The data medium storing program P may comprise routines for providing smooth motion of the fluid actuator arrangement in an automatic or semi-automatic way. The data medium storing program P comprises a program code stored on a medium, which is readable on the computer, for causing the control unit (e.g. the control unit marked with reference number 133, 233, 433, 533) to perform a method for raising and lowering a lifting member of a counterweighted roped hydraulic lifting system comprising a rope drive coupled to the lifting member and a rope guide pulley arrangement of a hoist arrangement; the rope drive is coupled to a piston rod extending through a first and second piston body, each of which partly being housed in a respective first and second cylinder of a fluid actuator arrangement coupled to a fluid supply via a valve arrangement and each of which exposing at least a first piston end portion outside the respective first and second cylinder; the hoist arrangement comprising a control unit coupled to the valve arrangement for operating the lifting member; a piston rod coaxially extends through the first and second piston body and a respective first and second engagement and disengagement device of the respective first and second piston body configured to alternately clamp around the piston rod; the piston rod partly or entirely features a counterweight mass and being configured to balance said lifting member, wherein the method comprises the steps of; alternately regulating fluid flow from the fluid supply to the respective first and second cylinder and to the respective first and second engagement and disengagement device for moving the piston rod downward; and alternately regulating fluid flow from the fluid supply to the respective first and second cylinder and to the respective first and second engagement and disengagement device for moving the piston rod upward.

The data medium storing program P further may be stored in a separate memory 760 and/or in the read/write memory 750. The data medium storing program P, in this embodiment, is stored in executable or compressed data format.

It is to be understood that when the processing unit 710 is described to execute a specific function that involves that the processing unit 710 may execute a certain part of the program stored in the separate memory 760 or a certain part of the program stored in the read/write memory 750. The processing unit 710 is associated with a data port 799 for communication via a first data bus 715. The non-volatile memory NVM 720 is adapted for communication with the processing unit 710 via a second data bus 712. The separate memory 760 is adapted for communication with the processing unit 710 via a third data bus 711. The read/write memory 750 is adapted to communicate with the processing unit 710 via a fourth data bus 714. The data port 799 is preferably connectable to data links of the fluid actuator arrangement.

When data is received by the data port 799, the data will be stored temporary in the second memory unit 740. After that the received data is temporary stored, the processing unit 710 will be ready to execute the program code, according to the above-mentioned procedure. Preferably, the signals (received by the data port 799) comprise information about operational status of the fluid actuator arrangement, such as operational status regarding the position of the piston rod relative the first and second cylinder. It could also comprise information about e.g. operational data regarding the speed and brake performance of the fluid actuator arrangement and/or lifting member status. According to one aspect, signals received by the data port 799 may contain information about actual positions of the lifting member by means of sensor members. The received signals at the data port 799 can be used by the CPU device 700 for controlling and monitoring of the raising and lowering of the lifting member in a cost-effective way. The signals received by the data port 799 can be used for automatically moving the lifting member between two end positions. The signals can be used for different operations of the fluid actuator arrangement. The information is preferably measured by means of suitable sensor members of the fluid actuator arrangement. The information can also be manually fed to the control unit (e.g. the control unit marked with any of reference numbers 133, 233, 433, 533) via a suitable communication device, such as a computer display.

The method can also partially be executed by the CPU device 700 by means of the processing unit 710, which processing unit 710 runs the data medium storing program P being stored in the separate memory 760 or the read/write memory 750. When the CPU device 700 runs the data medium storing program P, suitable method steps disclosed herein will be executed. A data medium storing program product comprising a program code stored on a medium is also provided, which product is readable on the computer, for performing the method steps according to claim 12, when the data medium storing program P according to claim 16 is run on a control unit (e.g. a control unit marked with any of reference number 133, 233, 433, 533).

The arrangement may according to different aspects be adapted to one or several of various industrial segments; construction industry, elevator manufacture industry, etc. The arrangement is not limited to be used in such segments, but also other industrial segments are possible. The present invention is of course not in any way restricted to the preferred embodiments described above, but many possibilities to modifications, or combinations of the described embodiments, thereof should be apparent to a person with ordinary skill in the art without departing from the basic idea of the invention as defined in the appended claims.

The valve arrangement may comprise a logic valve of suitable type. The valve arrangement may comprise 3/2 valves or others, or may comprise a two-way valve of any type suitable for control of the fluid actuator arrangement. The manoeuvring of the valve arrangement may be performed by means of a solenoid connected to a control unit adapted for controlling the valve arrangement and raising and lowering the lifting member. The fluid actuator arrangement may be adapted for fast and high clamp force engagement of the respective first and second piston body for propelling the latter accurate also for acceleration of heavy loads. By control of the valve arrangement including e.g. a logical valve, there is provided that the fluid actuator arrangement is capable to optionally perform lower force and/or slower motion rate of the lifting member.

A logical valve can be manoeuvred by the control unit to shut down the fluid flow to excluded cylinder/cylinders and direct fluid flow to only one cylinder. There are different types of valves that can be used for providing the above-mentioned aspects and other aspects, e.g. electro-hydraulic controlled valves and other types of directly controlled electro-hydraulic logical valves, etc.

The extendable and contractible cover member may be formed as a one-piece, undivided boot or bellow member or can comprise a plurality of cover sections depending upon application. Any type of suitable accordion shaped boot can be installed to protect the first and second piston body and to prevent ingestion of contaminant across the bearing members. The extendable and contractible cover member may have an oval shape, conical, dome-shaped, hemi-spherical, spherical or other shapes and may exhibit circular, oval, square or other suitable cross section.