Abstract: A guide-rail brake (1) of an elevator and a method for controlling the brake are provided. The brake comprises a frame part fixed to the elevator car, a prong part, which contains turning jaws (3,4) that correspond to the guide rail (2) via the braking surfaces when braking, a spring (10) loading the prong part to press the braking surfaces to the guide rail, and a controllable mover, which is an electromagnet (15), which contains two pulling core pieces (17,18). The force effect of the electromagnet (15) on the prong part is opposed to the spring. In the guide-rail brake an air gap (ag) is structurally arranged between the center parts (19,20) of the pulling core pieces (17, 18) of the electromagnet of the guide-rail brake when the brake is fully energized, and a damping circuit is arranged in the coil (16) of the electromagnet (15) of the guide-rail brake to speed up operation of the guide-rail brake.

Abstract: In an elevator apparatus, a brake device is controlled by a brake control device. The brake control device has a first brake control portion for operating the brake device to stop a car as an emergency measure upon detection of an abnormality, and a second brake control portion for reducing a braking force of the brake device when a deceleration of the car becomes equal to or larger than a predetermined value during emergency braking operation of the first brake control portion. The second brake control portion controls the brake device independently of the first brake control portion.

Abstract: In an elevator apparatus, a brake device stops a car from running. The brake device has a brake control portion for controlling a braking force generated at a time of emergency braking to adjust a deceleration of the car, and a timer circuit for invalidating the control of the braking force performed by the brake control portion after a lapse of a predetermined time from a moment when an emergency braking command is generated.

Abstract: An elevator hoist apparatus includes a stationary frame member, a main shaft, a stationary element disposed to said stationary frame member, a rotary frame member supported on said main shaft and extending in a radial direction in axial opposition to said stationary frame member, a rotary element disposed to said rotary frame member in opposition to said stationary member, a brake unit including a brake portion extending through an opening in said stationary frame member, and a rope sheave disposed to said rotary frame member for rotation therewith. The brake unit includes a brake portion disposed in a hollow portion of the stationary frame member of the stationary member and extending through the opening portion and disposed to the inner circumference of the stationary frame member or the rotary frame member. The magnetic path for the brake unit extends through one portion of the rotary frame member or the stationary frame member. Small-size and high performance are realized.

Abstract: An apparatus in an elevator for detecting and stopping an uncontrolled movement of the car when a machine brake intended to keep the elevator car immovable is on. The apparatus comprises a motion detector (1) for detecting movement of the car (2) and the length of the movement when the machine brake is on (10), a stopping device (3) for stopping an uncontrolled movement of the car, and limit and control means (4) for defining an allowed car movement and controlling the operation of the stopping device according to information obtained from the motion detector.

Abstract: An elevator system includes a car (1) traveling up and down along a hoistway; a buffer (15) for stopping the car (1) at an end of the hoistway, brakes (7), (8), and (9) for braking travel of the car (1); a car traveling-information acquisition means for acquiring car traveling information; and a brake control means (10) for controlling the brakes (8) and (9), based upon the information acquired by the car traveling-information acquisition means, so as to reduce a collision speed at a collision of the car with the buffer to below a predetermined speed so that a shock at the collision of the car (1) with the buffer (15) can be absorbed to a level below a specified value.

Abstract: The invention relates to methods for stopping elevators especially when using at least one three-phase motor operated by a static frequency converter. According to the invention, a brake relay controls the brake of the motor such that releasing of the brake relay causes the motor to be decelerated while the brake relay is coupled to a protective circuit in such a way that the control pulses required for generating the driving motor field are safely blocked when the brake relay is released.

Abstract: In an elevator apparatus, a brake device stops a car from running. The brake device has a power shutoff portion for shutting off a supply of power to a brake opening coil in response to a brake actuation command, and a current adjusting portion for supplying the brake opening coil with power while adjusting an amount of current in response to a deceleration reduction command from a brake control portion. The current adjusting portion can supply the brake opening coil with power even when the supply of power to the brake opening coil is shut off by the power shutoff portion.

Abstract: In an elevator apparatus, a rescue operation for a car is performed by a rescue operation controller. The rescue operation controller obtains a rescue operation voltage value and applies a voltage having the rescue operation voltage value to a brake coil in response to a signal from a speed detector at a time of the rescue operation for the car. The rescue operation voltage value is a value of the voltage necessary to reduce braking force of a brake device to move the car by using a state of imbalance between the car and a counterweight.

Abstract: An elevator apparatus performing proper braking control of a car according to a detected content of a failure, and including: a semiconductor switch connected in series to a brake coil, for varying current flowing through the brake coil; an interruption switch connected in series to the brake coil and the semiconductor switch and capable of interrupting current flowing through the brake coil; a braking force control processing mechanism controlling an amount of current flowing through the semiconductor switch according to deceleration of the car when the car stops; a failure detection section detecting failure in the braking force control processing mechanism; a critical event detection mechanism detecting a critical event requiring an urgent stop of the car based on a state detection signal; and a brake power supply interrupting mechanism turning the interruption switch OFF to apply braking when the failure and the critical event is detected.

Abstract: A control circuit for controlling an electromechanical elevator brake is disclosed. The control circuit includes at least one brake coil (L1), a direct-voltage source (BR1), a semiconductor switch arrangement, a current measuring unit, at least two semiconductor switches, and a control unit (CO1) for controlling operation of the circuit. The current measuring unit (Lm1) produces current data that is passed to the control unit (CO1). The at least two semiconductor switches (SW1, SW2) are controlled by the control unit (CO1) such that operation is alternated between the two so that the working condition of each switch can be checked in its turn on the basis of feedback data obtained from the current measuring unit.

Abstract: The invention relates to a method for controlling a braking unit of a rope transport installation and braking unit. The command signals of a first brake are modulated, until the installation is stopped, by a first modulation circuit integrated in the control unit to automatically regulate the running speed of the rope according to a first predetermined deceleration setpoint curve activated by a braking order. The command signals of a second brake are simultaneously modulated by a second modulation circuit integrated in the control unit to automatically regulate the running speed of the rope according to a second predetermined deceleration setpoint curve activated by the braking order, the instantaneous value of the second setpoint curve being at all times greater than the value of the first setpoint curve.

Abstract: In an elevator apparatus, a brake device stops a car from running. The brake device can adjust the magnitude of part of a total braking force generated at a time of emergency braking of the car. As an example of the brake device, the brake device has a nonadjustable brake portion for immediately generating a braking force without making an adjustment thereof at the time of emergency braking of the car, and an adjustable brake portion for generating a braking force while making an adjustment thereof at the time of emergency braking of the car.

Abstract: An elevator may include a hoisting machine, a set of hoisting ropes, a traction sheave, an elevator car, elevator car guide rails, and a brake. The hoisting machine may engage the set of hoisting ropes via the traction sheave in order to move the elevator car along the elevator car guide rails. The brake may be configured to affect rotational movement of the traction sheave. The brake may include a brake shoe and a braking surface. In an emergency braking situation in which the elevator car is moving upward, the brake shoe may be configured to move in a direction of rotation of the braking surface. An elevator brake may include a brake frame, a brake plate, a wedge piece, a brake shoe, at least one spring element, and at least one electromagnet.

Abstract: Provided is an elevator apparatus including a first electromagnetic switch and a second electromagnetic switch provided between a first electromagnetic coil and a second electromagnetic coil of a first brake device and a second brake device and a power source. The brake control section includes: a first electromagnetic coil control switch provided between the first electromagnetic coil and a ground section; a second electromagnetic coil control switch provided between the second electromagnetic coil and the ground section; a first processing section for opening and closing the first electromagnetic switch and the first electromagnetic coil control switch in response to a braking operation command issued from an operation control section; and a second processing section for opening and closing the second electromagnetic switch and the second electromagnetic coil control switch in response to the braking operation command.

Abstract: In an elevator device, movement of a car is braked by a brake device in a state in which driving of a hoist is stopped. While the drive of the hoist is stopped, braking force of the brake device is controlled by a brake control device based on a signal from a movement detector that generates a signal corresponding to movement of the car. The brake control device generates a target pattern for at least one of speed and acceleration of the car and controls braking force of the brake device such that the movement of the car follows the target pattern.

Abstract: Method for performing an elevator rescue run in an emergency situation, the elevator comprising and elevator car, a counter weight, a rope suspending the car and the counterweight, a drive motor, an emergency brake for stopping the car in an emergency situation, and a motor drive unit for supplying drive power to and for controlling the drive motor, having the following rescue run sequence steps: (a) operating the motor drive unit in a zero speed demand mode for holding the car at its present position; (b) lifting the brake, while holding the car in the zero speed demand mode; (c) determining the preferred movement direction of the car based on the power data as obtained by the motor drive unit; and (d) performing the rescue run in the direction of the determined preferred movement direction.

Abstract: An elevator drive has a brake device with compression springs to actuate brake levers, and brake linings on a brake drum creating a braking force. A sensor is provided to detect the movement of a brake magnet armature tappet. A bracket is attached to the brake magnet tappet on one end and a distance piece carrying the sensor housing is arranged on the other end. A restoring lug is attached to the existing mechanical indicator. A monitor evaluates the sensor signal and turns off the elevator drive in the event of dangerous operational states via a safety circuit. The system allows the state of the brake device to be monitored. The more the brake linings wear off due to abrasion, the smaller the distance between the armature and the brake magnet housing. If the armature is in contact with the brake magnet housing, the braking ability of the brake linings is completely void.

Abstract: An actuator has a driving first coil and a driving second coil. A capacitor is electrically connected to both the first coil and the second coil through a discharge switch using electric power accumulated in a capacitor which can be selectively supplied. An operation portion for operating the discharge switch is electrically connected to the discharge switch. For example, when an electric power supplied to the operation portion is cut due to a power failure, the second coil and the capacitor are electrically connected to each other through the discharge switch.

Abstract: In an elevator apparatus, a brake device stops a car from running. The brake device has a power shutoff portion for shutting off a supply of power to a brake opening coil in response to a brake actuation command, and a current adjusting portion for supplying the brake opening coil with power while adjusting an amount of current in response to a deceleration reduction command from a brake control portion. The current adjusting portion can supply the brake opening coil with power even when the supply of power to the brake opening coil is shut off by the power shutoff portion.

Abstract: A lift car with a brake device which is arranged in the region of the lift car for holding and braking the latter; the brake device includes a brake unit which can interact with a brake rail, an actuating device which can generate an actuator force, and a connector which connects the actuating device to the brake unit in a force-active manner in order to transmit the actuator force, wherein the brake unit is in its open position in the unloaded position.

Abstract: The invention relates to a fail-safe power control apparatus (3) for supplying power between an energy source (4) and the motor (5) of a transport system. The power control apparatus comprises a power supply circuit (6), which comprises at least one converter (7, 8) containing change-over switches (32), and the power control apparatus comprises means (24) for controlling the converter change-over switches, a data transfer bus (10), at least two controllers (1, 2) adapted to communicate with each other, and a control arrangement (11) for controlling a first braking device, and possibly a control arrangement (43) for controlling a second braking device.

Abstract: In an elevator apparatus, a brake device is controlled by a brake control device. The brake control device has a first brake control portion for operating the brake device to stop a car as an emergency measure upon detection of an abnormality, and a second brake control portion for reducing a braking force of the brake device when a deceleration of the car becomes equal to or larger than a predetermined value during emergency braking operation of the first brake control portion. The second brake control portion controls the brake device independently of the first brake control portion.

Abstract: In an elevator apparatus, a brake device stops a car from running. The brake device has a brake control portion for controlling a braking force generated at a time of emergency braking to adjust a deceleration of the car, and a timer circuit for invalidating the control of the braking force performed by the brake control portion after a lapse of a predetermined time from a moment when an emergency braking command is generated.

Abstract: An elevator machine (10) includes a machine shaft (14, 14?) and a sheave (26) that rotates with the machine shaft (14, 14?). A motor (12) selectively rotates the machine shaft (14, 14?). A brake (30) having at least one brake armature (36) selectively moves a brake rotor (28) coupled for rotation with the shaft (14, 14?) between a braking position and a released position. The brake rotor (28) selectively contacts a braking surface (44) formed directly on a housing (20, 22, 84, 90) to resist rotation of the machine shaft (14, 14?).

Abstract: Method and system for detecting and stopping uncontrolled movement of the car (1) in an elevator. In the method movement of the car is detected with the first movement detection means (2, 3, 4, 5, 6) when the brake (8) of the drive machinery (7) is in the braking status with the purpose of holding the car in its position without moving. A first control signal is formed if the car moves in the aforementioned situation. Movement of the car is stopped on the basis of the first control signal with a separate stopping appliance (9) with respect to the brake of the drive machinery. The operating condition of the first movement detection means are tested with the second movement detection means (10, 11, 12) during driving of the car in order to detect a fault situation. A second control signal is formed for the elevator control when a fault situation is detected, in which case the elevator control drives the car to the next stopping floor and prevents the subsequent run of the car.

Abstract: An emergency stop system for an elevator includes a state sensor for detecting an operation of a car, a brake device for braking the car, a brake controller for outputting a signal for operating the brake device based on a signal detected by the state sensor, and an uninterruptible power supply device for supplying electric power to the sensor, the brake device, and the controller. The controller has a signal processing/calculating unit for calculating the deceleration of the car based on the signal detected by the sensor, a command value calculating unit for calculating a command value for operating the brake device based on the deceleration of the car calculated by the processing/calculating unit, and a power monitoring device for monitoring state of the uninterruptible power supply device. At least one of the sensor, the processing/calculating unit, and the calculating unit includes independent systems.

Abstract: Provided is a braking device for an elevator in which energy required for braking and releasing is reduced. The braking device includes a movable plunger (5), braking mechanisms (1-4, 6, 7) which are connected to one end of the movable plunger and are switched between a braking state and a releasing state by an axial movement of the movable plunger, a first drive mechanism (10) using mechanical or magnetic force, for reversing the movable plunger in the middle of a movable range in an axial direction for the switching between the braking state and the releasing state to press and hold the movable plunger to the braking side or the releasing side, and a second drive mechanism (20) using an electromagnetic force, for driving the movable plunger to a reversion position in the middle of the movable range from the braking side or the releasing side against a pressing force of the first drive mechanism in order to switch between the braking state and the release state.

Abstract: In an elevator apparatus, a brake control device has a first brake control portion for operating a brake device upon detection of an abnormality to stop a car as an emergency measure, and a second brake control portion for reducing a braking force of the brake device when a degree of deceleration of the car becomes equal to or higher than a predetermined value at a time of emergency braking operation of the first brake control portion. The second brake control portion detects emergency braking operation of the brake device independently of the first brake control portion.

Abstract: In an elevator apparatus, a brake device is controlled by a brake control device. The brake control device is capable of performing braking force reduction control for reducing the braking force of the brake device at a time of emergency braking of a car. The brake control device monitors a running state of the car at the time of emergency braking thereof, and makes a switchover between validity and invalidity of braking force reduction control such that the car is stopped within a preset allowable stopping distance.

Abstract: A brake mechanism (10) for an elevator (2) is activated in response to an electronic control signal to prevent movement of an elevator car (16) under predetermined conditions. The brake mechanism is preferably a safety mechanism (10) and does not require a governor sheave, a governor rope, or a tension sheave. The safety mechanism in one disclosed example utilizes a solenoid actuator (22b) and an electric motor (40) and gear box assembly (42) to move safety wedges (18) into engagement with a guide rail (20) to stop the elevator car (16). The safety wedges (18) are held in a non-deployed position during normal elevator operation. If there is a power loss or if elevator car speed exceeds a predetermined threshold, an electronic control signal activates the safety mechanism (10) causing the solenoid to release, which causes the safety wedges (18) move in a direction opposite to that of a safety housing (12) mounted for movement with the elevator car (16).

Abstract: Elevator (2) comprising a car (4), a counterweight (6), a hoisting rope (8) for suspending the car (4) and the counterweight (6), a drive motor (10), a motor drive unit (26) for supplying the power to the drive motor (10), and a brake (18) for stopping the movement of the car (4) in an emergency situation, the elevator (2) further comprising an elevator rescue system (40), comprising an emergency power supply (42), an emergency brake switch (44) for connecting and disconnecting the power of the emergency power supply (42) to the brake (18), and an emergency drive switch (46) for connecting and disconnecting the power of the emergency power supply (42) to the drive motor (10), characterised in that the elevator rescue system (40) further comprises the motor drive unit (26) and a power line (74) connecting the emergency power supply (42) with the motor drive unit (26) and including the emergency drive switch (46).

Abstract: In an elevator apparatus, a brake device for braking the running of a car is controlled by a brake control device. The brake control device monitors a speed of the car and a degree of deceleration of the car at a time of emergency braking of the car. When the degree of deceleration of the car reaches a preset target deceleration, the brake control device generates a target speed pattern for decelerating the car from a speed of the car at that time.

Abstract: Method and system for detecting and stopping uncontrolled movement of the car (1) in an elevator. In the method movement of the car is detected with the first movement detection means (2, 3, 4, 5, 6) when the brake (8) of the drive machinery (7) is in the braking status with the purpose of holding the car in its position without moving. A first control signal is formed if the car moves in the aforementioned situation. Movement of the car is stopped on the basis of the first control signal with a separate stopping appliance (9) with respect to the brake of the drive machinery. The operating condition of the first movement detection means are tested with the second movement detection means (10, 11, 12) during driving of the car in order to detect a fault situation. A second control signal is formed for the elevator control when a fault situation is detected, in which case the elevator control drives the car to the next stopping floor and prevents the subsequent run of the car.

Abstract: In the invention a method is presented for ensuring operating safety in an elevator system, an elevator system, and a safety device of an elevator system. The elevator system includes at least an elevator car, elevator ropes, an elevator motor, a traction sheave and at least two holding brakes, which holding brakes are arranged to prevent movement of the elevator car when the elevator is stopped. According to the invention the first holding brake is engaged at the end of an elevator run, and the other holding brakes are engaged with a delay. When one holding brake is engaged, the state of motion of the elevator and any slipping of the brake is monitored. If the brake is detected as slipping, a procedure for preventing a hazardous situation is performed.

Abstract: The invented device works by attaching a rotor brake to the traction sheave while anchored to a solid object. When the traction sheave is rotating at normal speeds, the hydraulic pump maintains a consistent oil pressure in the storage tank. In the event of a sudden acceleration in either direction, the control box valve overflows the excess pressure and apples it to the rotor brakes, slowing the movement of the car and stabilizing the traction sheave in addition of the cargo and occupants.

Abstract: An encoder failure in an elevator drive system is detected and managed. A velocity of the elevator drive system is provided by an encoder signal (60) and compared with a minimum velocity threshold (62). An encoder fault timer is incremented when the velocity is less than the minimum velocity threshold (64). The elevator drive system is disabled when the encoder fault timer reaches a fault threshold time (66).

Abstract: An elevator drive with a brake device has compression springs that act on brake levers, whereby brake linings generate a brake force on a brake drum. The more the brake linings wear due to abrasion, the smaller the distance of the plunger from the brake magnet housing becomes. Should the plunger come into contact with the brake magnet housing, the braking capacity of the brake linings is completely eliminated creating an operating condition that is dangerous for elevator users. A switch is provided that detects a minimum distance. The switch can be arranged on the plunger of the brake magnet and detect the minimum distance to the brake magnet housing or, in the case of a retrofit, the switch can be arranged on the brake magnet rod and, for example, detect the distance of the second joint from the brake magnet housing, and at the minimum distance the switch switches.

Abstract: In an elevator apparatus, a car ascends and descends based on a running speed pattern generated by a control panel. Destination floor buttons and landing buttons are connected to an over speed monitoring portion without the intervention of the control panel. The over speed monitoring portion has an over speed setting portion for setting first and second over speeds based on car position information obtained from a car position detector and call registration information obtained from the destination floor buttons and the landing buttons. In the over speed setting portion, a running speed pattern different from the running speed pattern generated by the control panel is independently generated without depending on information from the control panel. The first and second over speeds are set based on the running speed pattern generated by the over speed setting portion.

Abstract: The invention relates to an elevator and an elevator brake, which elevator contains at least a hoisting machine (5) equipped with a traction sheave (6), a brake (10) affecting the rotational movement of the traction sheave and provided with at least one brake shoe (12) and a braking surface (11a), and hoisting ropes (3), which are fitted to move by means of the traction sheave (6) an elevator car (1) that moves along guide rails (4). In an emergency braking situation when the elevator car (1) is moving in the upward direction, the brake shoe (12) of the brake (10) is arranged to move in the direction of rotation of the braking surface (11a).

Abstract: A method of preventing a collision of two elevator cars of an elevator installation, which cars move substantially independently of one another in a common shaft, and an elevator installation includes a collision protection system that produces a retardation of each moved elevator car by a stopping brake as soon as the effective distance between the elevator cars falls below a critical minimum distance. After retardation of the cars by the stopping brakes, an emergency stop system comes into function. A control system of this emergency stop system ascertains the instantaneous movement state of the elevator cars. With the help of the car brakes, which are associated with the elevator cars, an additional retardation of each moved elevator car is triggered when the movement state thereof fulfils definable emergency stop criteria.

Abstract: A traction arrangement comprises a track, a carriage, guide means guiding the carriage along the track with a predetermined carriage/track gap, and eddy current means generating eddy current across the gap giving rise to a traction force. Such an arrangement has utility in ropeless elevator systems.

Abstract: Method for performing an elevator rescue run in an emergency situation, the elevator comprising and elevator car, a counter weight, a rope suspending the car and the counterweight, a drive motor, an emergency brake for stopping the car in an emergency situation, and a motor drive unit for supplying drive power to and for controlling the drive motor, having the following rescue run sequence steps: (a) operating the motor drive unit in a zero speed demand mode for holding the car at its present position; (b) lifting the brake, while holding the car in the zero speed demand mode; (c) determining the preferred movement direction of the car based on the power data as obtained by the motor drive unit; and (d) performing the rescue run in the direction of the determined preferred movement direction.

Abstract: In the invention a method is presented for ensuring operating safety in an elevator system, an elevator system, and a safety device of an elevator system. The elevator system comprises at least an elevator car, elevator ropes, an elevator motor, a traction sheave and at least two holding brakes, which holding brakes are arranged to prevent movement of the elevator car when the elevator is stopped. According to the invention the first holding brake is engaged at the end of an elevator run, and the other holding brakes are engaged with a delay. When one holding brake is engaged, the state of motion of the elevator and any slipping of the brake is monitored. If the brake is detected as slipping, a procedure for preventing a hazardous situation is performed.

Abstract: An elevator brake assembly (16) includes a plate (26) having damper assemblies (28) including at least one spring (30) for controlling movement of the plate (26) relative to a magnetic field generator (20). A biasing member (36) forces the plate (26) into engagement with a disk (22) fixed to a rotating shaft (18). A force created by the magnetic field generator (20) overcomes force of the biasing member (32) to draw the plate (26) into contact with the magnetic field generator (20). The impact between the plate (26) and the magnetic field generator (20) is controlled by the damping assembly (28) to substantially reduce impact noise.

Abstract: A combined elevator guiding and braking device (30) includes movable members (34) positioned symmetrically about opposite sides of guide rail (24). Guide members (40) are supported on the movable members (34) for following along the guide rail (24) under normal elevator system operation. When a safety braking function is required, braking members (44) engage the surfaces on the guide rail (24) when the movable members (34) move into a second operating position to achieve the braking function. The inventive arrangement integrates the car guiding and safety braking functions into a single device.

Abstract: The invention relates to an elevator system with at least one shaft, in which at least two cars can be made to travel along a common traveling path, and also with a shaft information system for determining the positions and speeds of the cars, which is connected to an electrical safety device.

Abstract: A cable control apparatus having a carrier and one or more trigger points disposed on a cable. A control mechanism controls movement of the cable and has a plurality of sensors to sense the one or more trigger points, and a motor to impart movement to the cable. A first sensor stops the motor and reverses direction of the cable to bring the predator to a base location, a second sensor stops the motor when the carrier reaches the base location, and a third sensor restarts the motor.

Abstract: The invention relates to a method for controlling a braking unit of a rope transport installation. The command signals of a first braking means are modulated, until the installation is stopped, by means of a first modulation circuit integrated in the control unit to automatically regulate the running speed of the rope according to a first predetermined deceleration setpoint curve activated by said braking order. The command signals of a second braking means are simultaneously modulated by means of a second modulation circuit integrated in the control unit to automatically regulate the running speed of the rope according to a second predetermined deceleration setpoint curve activated by said braking order, the instantaneous value of the second setpoint curve being at all times greater than the value of the first setpoint curve. The invention also relates to a braking unit of a rope transport installation enabling the method to be applied.

Abstract: A flexible construction for an elevator gearless traction drive machine having a frame that is easily adaptable to traction sheaves of differing widths and diameters while providing the necessary stability for the drive components without an additional structure. The frame is comprised of a pair of frame members joined by a plurality connecting rods. The connecting rods can be mounted in various positions based on the diameter of the sheave to avoid interference between the drive mount and suspension means. Longer or shorter connecting rods may be used based on the width of the sheave.