Abstract: A ventilation apparatus 26 is provided for mounting in a garage 10 door. The ventilation apparatus is provided with a rectangular shaped base support member 30 having an opening 40 formed therein. A first rectangular shaped tracking member 54 is aligned in first portions of the opening 40 in the base member 30. The ventilation apparatus 26 is also provided with a first transparent member 66 which is coupled in the first tracking member 54. A second rectangular shaped tracking member 56 is aligned in second portions of the opening 40 in the base support member 30. A second transparent member 82 is mounted for slidable movement in the second tracking member 56. This allows the second transparent member 82 to be moved to a position to cover the second portions of the opening 40 in the base member 30 as well as be moved to a position so that the second portions of the opening in the base member are uncovered.

Abstract: A substrate is coated by applying an essentially pure aluminum first layer to a surface of the substrate. At least a first portion of the first layer is oxidized so as to provide a protective coating of desired properties. The substrate may be a refractory metal-based investment casting core.

Abstract: A substrate is coated by applying a first layer atop the substrate and comprising, in major weight part, a non-refractory first metal. A second layer is applied atop the first layer and comprises, in major weight part, a carbide and/or nitride of a second metal. A third layer is applied atop the second layer and comprises, in major weight part, a ceramic. The substrate may be a refractory metal-based investment casting core.

Abstract: A wax or similar material may be molded to a base plate of an investment casting shelling fixture. The molding may provide for enhanced positioning of wax patterns or may provide a precise surface shape for the shell.

Abstract: A heat exchanger for viscous fluids includes a pair of frustum-shaped bodies (1) and (2) providing the heat-transmitting surfaces. The outer body is confined by gate-flanges (3) and (4) through which is inserted a bearing-and-seal housing (5). The inner body has a hollow center shaft (6) extending through the housing (5). The inner and outer bodies have one or more surface grooves (7). The outer body includes a jacket chamber (8) for a secondary, heat transfer fluid. The inner body is hollow, with channels to improve heat transfer, and the secondary fluid enters and exits through the hollow shaft (6). The angular movement of the inner body is also transferred through the shaft from an outside lever (9). The width of the grooves may exceed that of the scraper, allowing for relative radial movement of the scraper inside the groove. An axial force can be applied to increase the surface pressure of the scrapers.

Abstract: A heat exchanger having a plurality of stacked tubes (131) and tanks (110, 120) formed of resin and coupled to the longitudinal ends of the tubes (131), wherein the cooling liquid flowing in a fuel-cell (10) is cooled by being passed through the tubes (131) formed of double layers including a high heat conductivity resin portion (131a) and an insulative resin portion (131b).

Abstract: A heat exchanger assembly that addresses the thermal cycling problem to increase the durability of the heat exchanger core by fabricating at least the tube next adjacent to each of the reinforcing members with a cross section adjacent each of the headers including a radius having a partial maximum tube strain energy density and fabricating each of the reinforcing members with a connection section adjacent each of the headers having a reinforcement with a partial maximum strain energy density greater than the partial maximum strain energy density of the adjacent tube.

Abstract: An automotive air conditioning system comprising a main heating unit 4 for heating air passing through an air conditioning duct 2 with cooling water of an engine E and a refrigeration cycle device 20 having a first refrigerant circulating circuit 21 which is a cooler mode and a second refrigerant circulating circuit 22 which is a heater mode and whose operation is controlled by an ECU 10, wherein while the automotive air conditioning system is operated in a heater mode functioning as auxiliary heating, in the event that a heating load is equal to or larger than a predetermined value, a refrigerant compressor 7 is kept switched off until a predetermined time T1 has elapsed after the engine E has started. In addition, a heating device is provided on the refrigerant compressor or an accumulator so that the refrigerant compressor or the accumulator is heated by the heating devices while the automotive air conditioning system is operated in the heater mode functioning as auxiliary heating.

Abstract: The present invention provides a heating/cooling control system that can effectively control the temperature of the air discharged at the rear interior of the motor vehicle. The heating/cooling control system includes a front control and a rear control. The front control is capable of operating within a predetermined temperature range. The temperature range of the rear control is based on the set point of the front control.

Abstract: A method and apparatus for improving the performance of production-injection wells whereby a pump (35), driven by a hydraulic turbine (32) sharing the same central shaft (33, 34), is run and set in an oil-producing well. The oil enters the annulus of the well from the production zone and is induced into the pump to be forced to the wellhead; the injection water is forced down the wellbore to drive the turbine whereafter the injection water exhausts through the pump to be injected into the underlying aquifer thereby providing additional pressure support to the producing zone.

Abstract: The present invention provides a method, apparatus, and system to shear a tubular member disposed in a well and seal the wellbore using a unique blade seal. In at least one embodiment, the blade seal is adapted to interface with opposing rams in a blowout preventer. The blade seal uses a combination of arcuate surfaces with a common centerpoint to interface with corresponding surfaces in a ram block of a ram. The blade seal retains sealing capabilities used for wells and at the same time reduces the forces on the ram body to reduce failures from overpressurization. Further, the blade seal can be used in existing blowout preventers bodies that heretofore have been overstressed by prior art designs.

Abstract: The present invention provides for multiple pathways by which fluid can enter one or more alternate pathway conduits. Entrance tubes can be arranged such that their spacing prevents all of them from being simultaneously obstructed, covered, or otherwise blocked.

Abstract: A test plug tool for use in testing a pressure integrity of a pressure control stack mounted to a wellhead, including a joint between a casing and a casing support in the wellhead. The test plug tool includes a test plug of an appropriate diameter used to pressure test the pressure control stack as well as a joint between any one of a surface casing and the wellhead, an intermediate casing and an intermediate casing mandrel, and a production casing and a production casing mandrel. The pressure integrity of the wellhead is ensured at each stage of well drilling and well completion, and safety is improved. Optionally, a backpressure valve permits pressurized fluid that leaks below the test plug tool to flow upwardly through a central bore in a landing tool that is secured to the test plug tool to permit detection of the leak.

Abstract: A method for producing a gas and a liquid in a subterranean well includes the step directing a gas flow in a well annulus through one or more baffle plates to separate at least some of the liquid from the gas. The method can also include the steps of directing the separated liquid down the annulus towards a producing formation of the well, dehydrating the gas flow proximate to a surface of the well, and then directing the dehydrated gas flow to the surface. A system for performing the method includes a set of baffle plates located proximate to the producing formation configured to provide a tortuous path for the gas flow through the annulus, and a single baffle plate located proximate to the surface configured to dehydrate the gas flow. In addition to separating the liquid from the gas flow, the set of baffle plates maintains a single phase wet gas above the baffle plates, and a liquid phase below the baffle plates.

Abstract: A method of hydraulically fracturing a hydrocarbon-bearing subterranean formation ensures that the conductivity of water inflow below the productive zone of the subterranean formation is reduced. The method consists of two principal steps. In the first step, a fracture in and below the productive zone of the formation is initiated by introducing into the subterranean formation a fluid, free of a proppant, such as salt water, fresh water, brine, liquid hydrocarbon, and/or nitrogen or other gases. The proppant-free fluid may further be weighted. In the second step, a proppant laden slurry is introduced into the subterranean formation which contains a relatively lightweight density proppant. Either the fluid density of the proppant-free fluid is greater than the fluid density of the proppant laden slurry or the viscosity of the proppant-free fluid is greater than the viscosity of the proppant laden slurry.

Abstract: The present invention relates to spacer fluids used in subterranean operations and, more particularly, to spacer fluids that comprise water-soluble relative permeability modifiers and methods of using the spacer fluids in subterranean operations. In one embodiment, the present invention provides a method of displacing a first fluid from a well bore that comprises introducing the first fluid into the well bore; and displacing the first fluid with a spacer fluid, the spacer fluid comprising water, and a water-soluble relative permeability modifier comprising a hydrophobically modified polymer or a hydrophilically modified polymer. In another embodiment, the present invention provides a spacer fluid that comprises water, and a water-soluble relative permeability modifier comprising a hydrophobically modified polymer or a hydrophilically modified polymer.

Abstract: A fluid-loss pill that includes a brine solution and an effective amount of a viscoelastic surfactant is disclosed. The viscoelastic surfactant preferably includes at least one compound selected from the family of compounds described by where R1, R2, R3, R4 and R5 are carbon atom or carbon chains, saturated or unsaturated, single or multiple unsaturation, straight chain, branched chain or cyclic including aromatic or alicyclic groups, and R1 contains 16–26 carbon atoms, R2 contains 2–10 carbon atoms, R3, R4 and R5 contains 1–6 carbon atoms. Methods of treating a well that include injecting fluid-loss pill into a well to control lost-circulation or to kill a well.

Abstract: Method and apparatus for servicing of a bore hole in the earth, comprising a first sub-assembly adapted for the insertion and removal of a continuous length of coiled tubing into and from the bore hole, a second sub-assembly adapted for the vaporization of liquified gas and the pumping of the resulting gas through the coiled tubing into the bore hole and a platform to support both the first and second sub-assemblies thereon.

Abstract: In accordance with one embodiment of the present invention, a method for lining a lateral wellbore includes drilling a main wellbore extending from a surface to a subterranean zone, casing the main wellbore with a main casing having a plurality of lateral wellbore windows formed therein, positioning a whipstock having a longitudinal bore running therethrough adjacent a respective one of the lateral wellbore windows, forming a lateral wellbore through the respective lateral wellbore window using the whipstock, lining the first lateral wellbore with a lateral liner and a portion of a tie-back assembly that has a pre-milled lateral wellbore window formed therein, aligning the pre-milled lateral wellbore window with the longitudinal bore, and coupling the tie-back assembly to the main casing.

Abstract: An industrial scale fire fighting nozzle and method, the nozzle having a selectively adjustable discharge gap and providing for gap coordinated, independently selectable additive proportioning ratio selection, the method including discharging fire fighting fluid at a selectively adjustable flow rate with an independently selectable, gap coordinated adjustable additive proportioning ratio, and use of reinforced high temperature polymer for at least a barrel element or a bafflehead element component.

Abstract: Methods are provided for a provision of hypoxic hypercapnic and hypoxic hypocapnic fire-extinguishing compositions for continuous use in human occupied environments. Breathable fire preventative atmospheres can be created using air separation and having increased or decreased carbon dioxide content.

Abstract: A shaft comprises an input portion and a tang. The tang has a first section, a second section, and a radial bore. The second section is disposed between the first section and the input portion along an axis. A radial cross section of the first section is less than a radial cross section of the second section. The radial bore is disposed on the first section.

Abstract: A flow guide configured for insertion in a cavity defined between an outer housing and a nested inner motor housing of a fluid driven tool. The flow guide defines a longitudinal axis and includes at least two longitudinal portions disposed parallel to the longitudinal axis and defining a longitudinal channel therebetween, and a rib being substantially circumferential and connecting the longitudinal portions at points defining a plane substantially transverse to the longitudinal axis. The rib defines a recess that permits fluid communication in the longitudinal channel across the rib.

Abstract: A method and system for testing a partially formed well includes forming a first well bore intersecting a subterranean formation. The first well bore includes a portion of a planned well having a first configuration. A production characteristic of the subterranean formation is tested through the first well bore in the first configuration. The first well bore is reconfigured to a second configuration different from the first configuration. The production characteristic of the subterranean formation is re-tested through the first well bore in the second configuration. Further formation of the planned well is planned based on testing of the subterranean formation through the first well bore in the first and second configurations.

Abstract: A method and apparatus for use in assessing down-hole drilling conditions are disclosed. The apparatus includes a drill string, a plurality of sensors, a computing device, and a down-hole network. The sensors are distributed along the length of the drill string and are capable of sensing localized down-hole conditions while drilling. The computing device is coupled to at least one sensor of the plurality of sensors. The data is transmitted from the sensors to the computing device over the down-hole network. The computing device analyzes data output by the sensors and representative of the sensed localized conditions to assess the down-hole drilling conditions. The method includes sensing localized drilling conditions at a plurality of points distributed along the length of a drill string during drilling operations; transmitting data representative of the sensed localized conditions to a predetermined location; and analyzing the transmitted data to assess the down-hole drilling conditions.

Abstract: Methods and apparatus facilitating logging-while-drilling (LWD) using a multi-pole acoustic transmitter source. The multi-pole transmitter source enables measurement of formation velocities, including shear wave velocities through formations that are slower than velocities through local fluids. The methods and apparatus may be utilized for LWD and wireline seismic surveys in which both the seismic or acoustic source and receivers are both deployed in a borehole, but may also be used for VSPs (vertical seismic profiling).

Abstract: A rotary drill bit assembly suitable for directionally drilling a borehole into an underground formation, the drill bit assembly having a bit body extending along a central longitudinal bit-body axis, and having a bit-body face at its front end, wherein an annular portion of the bit-body face is provided with one or more chip-making elements; a pilot bit extending along a central longitudinal pilot-bit axis, the pilot bit being partly arranged within the bit body and projecting out of the central portion of the bit-body face, the pilot bit having a pilot-bit face provided with one or more chip-making elements at its front end; a joint means arranged to pivotably connect the pilot bit to the bit body so that the bit-body axis and the pilot-bit axis can form a variable diversion angle; and a steering means arranged to pivot the pilot bit in order to steer the direction of drilling.

Abstract: A modularly segmented apparatus for precise borehole pressure control, removing waste from borehole fluid, and recirculating the cleaned borehole fluid includes a pressure control section, a gas separator section, and a waste management section. In the pressure control section, a pressure manifold interconnects a plurality of chokes. A plurality of valves are used to direct the contaminated fluid through one of the chokes, which maintains a precise and predetermined pressure in the system. The manifold, chokes, and valves are mounted on a skid for easy transport. In the gas separator section, a gas separator is used to remove a majority of the gases present in the contaminated borehole fluid. In the waste management section, a vibratory separator removes large solid contaminants from the degassed fluid. The solids are directed to a solids collection container for further treatment or disposal. The fluid is directed to a first pit, which may be one partitioned are of a larger collection tank.

Abstract: A coupler for use in connecting together in a driving relationship a first member and a second member in a drill bit assembly. The coupler includes an elongate body that has opposite axial forward and rearward ends as well as contains a longitudinal bore. The elongate body further has a mediate collar wherein there is a forward body portion axial forward of the collar and a rearward body portion axial rearward of the collar. The forward body portion is suitable to drivingly engage the first member. The rearward body portion is suitable to drivingly engage the second member. Each one of the forward and rearward body portions carries seal. The elongate body further carries a retention member.

Abstract: The side tracking system includes a window mill having a full diameter cutting surface and a reduced diameter tapered cutting surface and a whipstock having a ramp engaging the reduced diameter cutting surface. The materials of the whipstock have a first cutablity and the materials of the casing have a second cutability. The reduced diameter cutting surface contacts the whipstock ramp at a first contact area and the full diameter cutting surface contacts the wall of the casing at a second contact area. As weight is applied to the mill, there is a first contact stress at the first contact area and a second contact stress at the second contact area. A cutability ratio is the first cutability divided by the second cutability and a contact stress ratio is the first contact stress divided by the second contact stress. The mill cuts the casing rather than the whipstock by maintaining the product of the cutability ratio and the contact stress ratio less than one.

Abstract: A percussion drill bit for drilling a bore includes a drill body having a connecting section at a rear end thereof for connection to a percussive unit, and a plurality of cemented carbide buttons embedded in a front end of the drill body. Each button comprises a cemented carbide body having a rear mounting portion embedded in the drill body, and a front end protruding from the drill body. The front end of the cemented carbide button is substantially semi-spherically curved and defined by a radius whose origin is disposed axially rearwardly of a plane through the largest diameter of the button. The button projects from the drill bit body a distance which is not less than 50% of the button diameter. A conical intermediate surface forms, in cross-section, an acute angle of about 13–19° with an envelope surface of the rear mounting portion.

Abstract: A transportable power wheelchair is provided which employs a variety of detachable modules to facilitate transportation and storage. The wheelchair may be readily disassembled/reassembled by a single individual without assistance and/or the need for special tools. The wheelchair includes a power supply unit, a pair of primary drive wheels, and a drive train subassembly mounting and independently driving each at least one of the drive wheels. First and second main frame subassemblies preferably have mounted thereon one of the drive train subassemblies. The power supply unit is also detachably mounted therebetween. At least one cross member assembly connects the main frame subassemblies. The cross member assembly, in combination with the main frame subassemblies, define the main frame assembly. A seat is also detachably mounted to the main frame assembly by means of the cross members.

Abstract: A hybrid vehicle drive system including (a) an engine, (b) an electric motor, (c) a planetary gear device having a first rotary element connected to the engine, a second rotary element connected to the electric motor and connected through a first clutch to an output member connected to vehicle drive wheel, and a third rotary element connected through a second clutch to the output member, (d) a forward-motor-drive control device for engaging the first clutch and releasing the second clutch to thereby establish a forward motor drive mode in which the vehicle is driven in a forward direction by the electric motor, (e) a forward-engine-drive control device for engaging at least the second clutch to establish an engine-drive mode in which the vehicle is driven in the forward direction by the engine, and (f) a second-clutch control device operable upon switching of a vehicle drive mode from the forward motor drive mode to the forward engine drive mode, for engaging the second clutch only after the engine speed has

Abstract: This application relates to a hybrid power supply apparatus including a fuel cell and an energy storage device for use in off-road electric vehicles, such as lift trucks. The apparatus is a substitute for conventional lead acid batteries and is sized to fit within a conventional lift truck battery receptacle tray. The fuel cell and fuel processor systems are designed to meet the average load requirements of the vehicle, while the batteries and power control hardware are capable of responding to very high instantaneous load demands. The invention has a similar electrical interface as conventional battery systems and does not require vehicle modification. The apparatus is air-cooled to ensure that the hybrid power components operate within a preferred temperature range and to maintain the external surfaces of the apparatus and exhaust gases within safe temperature limits.

Abstract: A front hood assembly has the front hood of a motor vehicle hinged to the chassis of the motor vehicle via at least one hinge, the front hood being lockable via at least one hood lock for locking the front hood with the body of a motor vehicle. To this end, the hood lock allows a horizontal displacement of the front hood even if it is locked. The locking element of the front hood allows a displacement of the front hood into horizontal escape space while the front hood remains locked.

Abstract: A collapsible three wheeled vehicle for personal transportation which has a removable support bracket that secures the distal ends of two independent foldable side rails at either end of the support bracket. The support bracket also provides a mounting base for a passenger seat. The rear support bracket, when removed, allows the side rails to fold together with the steering column for convenient storage. A removable front wheel, a removable seat, and removable steering handles allow the vehicle to further reduce the required amount of space for storage and transport. The vehicle uses a battery operated electric drive motor. A second optional battery power supply may be attached to the vehicle to extend its range. A storage bag is provided to hold the components of the vehicle when not in use.

Abstract: A three-wheeled motor vehicle includes a through coupling situated between right and left internal shafts and rear wheels, each via a drive shaft. The axial lines of right and left internal shafts are both intersected with a straight line as a rocking axis. If the right and left internal shafts are placed away from each other in the front and rear of the vehicle body, the drive shaft can be placed extensively in the diagonal direction from the right and left internal shafts to the rear wheel side. Using the described structure, the total length of the drive shaft can be increased. In consideration thereof, the bending angle of the drive shaft can be minimized when the rear drive wheels move in the vertical direction, and the track of the rear wheels can be reduced because the drive shaft is placed extensively in the diagonal direction.

Abstract: A two speed drive system for an all wheel drive vehicle includes a double planetary gear front differential and a power take-off unit transferring drive torque to a front wheel set and a rear wheel set of the vehicle. A rear differential connects the power take-off unit and the rear wheel set providing the drive torque to the rear wheel set. A two speed drive unit is positioned between the power take-off unit and the rear differential. The drive unit shifts between a high range drive operation and a low range drive operation. The drive unit may be mounted directly to either the power take-off unit or the rear differential.

Abstract: An impact sensing apparatus for a motor vehicle includes a control module having an accelerometer and a contact switch mounted in a bumper of the motor vehicle. The contact switch is in an open position and is in communication with the control module. The control module deploys an airbag when the accelerometer detects a change in velocity of the motor vehicle exceeding a threshold lowered when the contact switch is urged by the bumper to a closed position.

Abstract: Steer unit for steer-by-wire comprising angle sensing means (12) for detecting the angular position of a steering wheel (11), processing means (10) connected to the angle sensing means (12) and connectable to a wheel position sensor (22), the wheel position sensor (22) being arranged for providing an output signal representing the position of steered wheels (20) of a vehicle. The processing means (10) are connectable to a steering actuator (21) mechanically coupled to the steered wheels (20), the processing means (10) being arranged for driving the steering actuator (21) dependent on the angular position of the steering wheel (11). The steer unit further comprises friction means (14) for providing a friction force on the steering wheel (11), the friction means (14) being connected to the processing means (10), and the processing means (10) being arranged for driving the friction means (14) in dependence of the wheel position sensor output signal.

Abstract: A motor-driven power steering system includes a power assisting motor; a motor current sensor, a sample-hold circuit that has sampling section and a holding section, a timing signal generating circuit that generates a timing signal to activate either the sampling section or the holding section and an alarming unit that generates an abnormality signal if the timing signal is not detected for a prescribed period.

Abstract: An acoustic impedance matching enclosure is provided having a driver loaded into a chamber buffering the throat/mouth of a closed loop transmission line. Transmission line consists of a termination member, outer and inner enclosure walls, high-density lining and throat/mouth area. Transmission line eliminates internal random standing waves while providing variable-frequency standing waves that through superposition of the waves compensates for mass-acceleration loss of the high-end of the driver output while damping the resonance of the driver. Alternative application of the acoustic impedance matching enclosure is that of compression loading the driver directly into the closed loop transmission line and using an acoustic low pass filter to translate the output into low frequencies only through a port.

Abstract: A supporting bracket assembly for a horizontal lifeline cable (4) comprises a base plate (14), bracket means (24) and holding means (28) for the cable. The base plate (14) is provided for securing to a structure (6). The bracket means (24) is secured to the base plate and adapted for frictionally restrained pivotability with respect to the base plate and the holding means (28) for the cable (4) is secured to the bracket means (24). In this way, dynamic loading of the cable (4) results in pivoting of the bracket means (24), against frictional restraint, from a first position (36) into a second position (38).

Abstract: A removable tree stand with a novel shur lok latch. A platform extends laterally outward from the tree in a nominally horizontal position. The platform end proximal to the tree includes a mechanism for engaging the tree. Integral tubular support arms project up at an angle from both sides of the platform to a height above the platform. A support cable, including a plurality of mechanical stops, encircles the tree trunk and is inserted through both tubular support arms. The first key feature is a novel pivoting cable engagement mechanism, called a shur lock latch, on each support arm that is easily engaged and provides a positive lock that prohibits inadvertent disengagement of the support cable in both the loaded and unloaded condition. A second key feature is that the support cable is powdercoated to provide increased durability.

Abstract: A reinforcement pad for protecting a liner of a pool from damage caused by a user ascending and descending a pool ladder having two upper ends and two lower ends. The reinforcement pad has a substantially oval pad base and a substantially cylindrical socket extending therefrom. The socket, which has a centrally located bore, is mateable with only one lower ladder end. A user inserts one lower ladder end into the bore of the socket of one reinforcement pad. The user then repeats this step with the other lower ladder end and another reinforcement pad. Next, the user positions the pad base against the pool liner and attaches the upper ladder ends to the pool deck. The pad distributes pressure applied to the ladder over the wider area of the lower surface of the pad base, thereby preventing the liner from becoming damaged.

Abstract: A method for converting an engine from petroleum based engine oil to synthetic oil, whereby substantially all petroleum based engine oil is removed prior to replacement with synthetic engine oil.

Abstract: A method and apparatus for filling a transmission at the transmission assembly plant including the steps of pumping fluid through the transmission entering at a first port and exiting through a second port, rotating the torque converter to purge trapped air, shifting the transmission, filling the transmission to a desired level and plugging the first and second ports. Through use of the method and apparatus of the present invention, the transmission is placed in a “road ready” condition and will not require additional fluid to be added in a top off operation at the vehicle assembly plant.

Abstract: A lift having a safety lock system includes a mast that may be supported by a base, and a frame that can be lifted or lowered along the mast. The safety lock system includes a first support beam that is located adjacent to the mast and a second support beam that is located opposite the first support beam relative to the mast. The safety lock system also includes a first lock and a second lock. Each of the first lock and the second lock are operable between a plurality of locked positions and an unlocked position. In the locked position, the first lock is engaged with the first support beam to lock the lift frame to the first support beam, and the second lock is engaged with the second support beam to lock the lift frame to the second support beam. Each of the first lock and the second lock can be placed in the unlocked position, wherein the lift frame can be freely lifted or lowered relative to the mast.

Abstract: An elevator installation has a support device engaging a driven drive pulley for driving an elevator car. The support device loops around the drive pulley at least partly and has a safety section which is so arranged that the safety section interacts with the drive pulley when the elevator car or a counterweight after overrunning an upper position approaches an upper shaft end. The safety section is formed in such a manner that a slipping through results due to the interaction between the drive pulley and the support device.

Abstract: An elevator in which the elevator car is suspended by means of hoisting ropes consisting of a single rope or several parallel ropes, said elevator having a traction sheave which moves the elevator car by means of the hoisting ropes. The elevator has rope portions of the hoisting ropes going upwards and downwards from the elevator car, and the rope portions going upwards from the elevator car are under a first rope tension (T1) which is greater than a second rope tension (T2), which is the rope tension of the rope portions going downwards from the elevator car, and that the elevator comprises a compensating system for keeping the ratio (T1/T2) between the first and the second rope tensions substantially constant.