Abstract: A method for limiting the speed of a hoist mounted to a mobile well service rig involves determining a safe speed limit that ensures the hoist's capable stopping time is less than the maximum allowed time for stopping. In some examples, the maximum allowed time for stopping is based on the wellstring's modulus of elasticity and independent of the hoist's braking characteristics. The capable stopping time, however, is independent of the wellstring's modulus of elasticity and dependent on the hoist's braking characteristics.

Abstract: The invention relates to a mooring arrangement (2, 2?) for a floating device (1, 2) comprising a band (5) and a drum (3) adapted to pay out and pull in the band (5). The invention being distinctive in that the mooring arrangement (2, 2 further comprising a band guide (14, 15,22), said band (5) is extending from the drum (3) via the band guide (14, 15, 22) and is adapted to be coupled to an anchoring arrangement (13), said band said band guide (4, 15, 22) being configured to tilt about an articulation axis (A, B) being parallel with a longitudinal axis of the part of the band (5a) situated between the drum (3) and the band guide (14, 15, 22) in order to position the band (5) to compensate for movement in the floating device (1,12, 12?) and thus reduce the wear in the band (5).

Abstract: The monitoring of a brake is disclosed. The brake includes first and second braking surfaces and a magnetizing device arranged to move the braking surfaces to an open state, in which the braking surfaces are separated from each other, and to a closed state, in which the braking surfaces are connected to each other. During the monitoring of the brake, the time is measured that elapses from the change in the magnetic field caused by the magnetizing device to the shift of the braking surfaces from one state to another.

Abstract: Braking systems and methods are provided for a drum wench system having a winch drum having an outer surface and a winch drum braking system. The winch drum braking system has a first brake having a first brake lining, located adjacent to the winch drum, and a first three-ring ratchet linkage system connected to the first brake lining. The first three-ring ratchet linkage system is rotatable and adapted to move the first brake lining to a first position or a second position with respect to the outer surface of the winch drum. In the first position, the first brake lining contacts the outer surface of the winch drum to apply break force thereon, and, in the second position, the first brake lining is separated from the winch drum.

Abstract: A winch clutch includes a driving block and a driven block respective connected to a motor and a transmission shaft of a deceleration clutch mechanism of a winch, the driving block and the driven block each having two spaced protruding flanges, a brake spring mounted between the driving block and the driven block and having retaining end portions disposed at two opposite ends thereof and respectively engaged into gaps between the protruding flanges of the driving block and gaps between the protruding flanges of the driven block, a brake bush accommodating the driving block, the driven block and the brake spring, and a one-way bearing fixedly mounted in the winch around the brake bush to limit rotation of the brake bush in a first direction. Thus, the winch brake has the characteristics of high reliability and high durability.

Abstract: Disclosed is a hoist equipped with a power-off type electromagnetic brake, wherein, at positions corresponding to an upper portion and a lower portion of a brake disk of an electromagnetic brake cover surrounding the electromagnetic brake, there are respectively provided insertion openings for first and second operation levers to be vertically inserted between an armature and a pressure-receiving plate. The first operation lever has an insertion portion to be fitted from above into the insertion opening to be inserted between the armature and the pressure-receiving plate, a retaining portion horizontally bent from the insertion portion, and a connection portion downwardly bent from the retaining portion to be connected with the second operation lever, and the second operation lever has an insertion portion fitted from below into the lower insertion opening to be inserted between the armature and the pressure-receiving plate, and an operation portion horizontally bent from the insertion portion.

Abstract: An air balancer has a rotary drum on which a rope member is to be wound and that is supported rotatably by a stationary shaft in a casing, a conversion system that converts pressure of first air supplied into the casing into rotational force of the rotary drum for winding the rope member on the rotary drum, a rotary member that is rotatably supported by the stationary shaft and linked with the rotary drum to integrally rotate therewith, a rotation restriction member to be in contact with the rotary member to restrict rotation thereof, a disengagement mechanism that causes the rotation restriction member to retract by pressure of second air supplied into the casing to thereby disengage the contact between the rotary member and the rotation restriction member, and a control module having an air circuit that supplies the second air into the casing only when the first air is supplied into the casing or when the first air is discharged from the casing.

Abstract: A dismantable hoist for storing and transporting wire rope and for lowering and raising the wire rope from a building roof site including a lightweight frame having a base, lightweight reel, for storing the wire rope, having a central drum and a pair of spaced-apart peripheral rings attached to the drum forming opposed side flanges rotatably mounted in the frame, drive means removably attached to the drum for rotating the drum for lowering and raising the wire rope, and brake means operatively connected to the spaced-apart peripheral rings and normally biased into braking engagement with the peripheral rings to stop lowering of the wire rope upon release of the brake means.

Abstract: The invention relates to an electromagnetically ventilating spring-pressure brake for mounting on the driving disk (15) or the driving disk shaft (16) of already existing elevators, which are operated with cables passing over a driving disk. The external-mounted brake (1) is situated concentric to the central axis of the driving disk (15) or driving disk shaft (16) on a separate base (23) of the structure on the free side (i.e. opposite the driving side) of the driving disk (15) and is fastened in a stationary and rotationally fixed manner. The rotor (5) of the brake (1) is connected in an essentially rotationally fixed manner to the free end of the driving disk (15) or of the driving disk shaft (16) in order to transmit the braking torque of the external-mounted brake to the driving disk (15).

Abstract: A lift assembly having a drum rotatably mounted to a frame and linearly translatable with respect to one or more portions of the frame. A plurality of head blocks can be connected to the frame along a helical mounting path, wherein linear translation of the drum during takeoff or take-up can maintain a predetermined fleet angle between a take off point from the drum and the head block.

Abstract: A safety device with fall arrest and descending modes includes a housing, a drum, a lifeline, first and second brake assemblies, and a control. The drum is rotatably operatively connected to the housing. The lifeline has an intermediate portion interconnecting a first end and a second end. The first end is operatively connected to the drum. The first and second assemblies are operatively connected to the drum. The control is operatively connected to the first and second brake assemblies and has a first position and a second position. The first position selectively engages the first brake assembly in a descending mode and the second position selectively engages the second brake assembly in a fall arrest mode.

Abstract: A drawworks having a drum spool, a drum shaft concentrically supported by the drum spool, a rotary union, brake assemblies and a brake cooling system which circulates a cooling fluid through the brake assemblies to thereby reduce the operating temperature of the brake assemblies. The brake cooling system includes a cooling fluid passage that extends through the drum spool, the rotary union and the brake assemblies.

Abstract: An elevator brake (20) rotor for use in an elevator machine (10) includes a non-metallic elevator brake hub (36) and a metal flange (34), both of which have an opening with a splined portion for guiding axial movement of the rotor along a rotable shaft (14). This arrangement reduces metal-to-metal contact between the rotor and shaft and reduces noise.

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: Brake equipment for holding and braking an elevator car in an elevator installation, which is arranged to be movable along a brake track in two directions of travel, includes a mount with a brake lining which automatically adjusts under friction couple with the brake track on movement of the elevator car relative to the rail and in that case tightens a first tightening means, which can be released by an actuator. The first tightening means tightens the mount together with the brake lining against the brake track by a biasing force. The brake equipment produces, with unmoved brake equipment and an unreleased state of the actuator, a holding force acting in both directions of travel. The holding force is determined substantially by the biasing force acting on the mount.

Abstract: A braking device for a power winch includes a reduction box installed inside with a sectional shaft, an elastic member, a fixing base, a braking lining, a first engraved block, a second engraved block and a clutch base. The fixing base is fixed in the accommodating hollow of the reduction box. The braking lining is an independent component composed of at least two blocks integrated to form a ring-shaped braking lining assembled in the accommodating hollow and positioned abutting the inner edge of the accommodating hollow, the fixing base and the first engraved block, having a small gap formed between them. Only when the motor stops operating and the power winch performs braking, will the braking lining produce friction with the inner edge of the accommodating hollow, the fixing base and the first engraved block, able to prolong service life and facilitate replacing of the braking lining.

Abstract: The invention concerns a safety brake mechanism for the winding drum (8) of a hoisting machine that can be driven via a motor (4) with lifting gearbox (3), which is substantially braked to a standstill without jerking when the lowering speed is excessive by a brake ring (12) that revolves concentrically with the winding drum (8) and is frictionally joined to the latter, when the brake ring (12) lying against a cylindrical brake surface (23) of the hoisting machine is locked. In order to allow for the grinding and adjusting of the necessary braking moment in the disconnected condition of the winding drum prior to the assembly of the complete lifting mechanism with low expenditure of material and cost, the brake surface (23) for the brake ring (12) may be provided on its outer circumference with a rigid coupling (10) that concentrically connects a lifting gearbox (3) and a winding drum (8), to which the lifting gearbox (3) and winding drum (8) are removably connected.

Abstract: A brake structure for a roll-up door includes a brake drum fixed to a transmission shaft of a speed reducer. The brake drum receives a pair of brake shoes in opposite inner sides thereof. The brake shoes are pivotably connected to each other at an end of each brake shoe. A linking resilient member is connected between the free ends of the brake shoes. A brake pad is attached to a surface of each brake shoe facing the inner surface of the brake drum. A controlling lever is disposed at the top of the speed reducer corresponding to the free ends of the brake shoes. One end of the controlling lever is connected to an end of a fixing resilient member. The other end of the fixing resilient member is connected to a moving iron of a first solenoid. A clasping block is connected to the moving iron of the first solenoid. The other end of the controlling lever is connected to a moving iron of a second solenoid.

Abstract: An apparatus includes a bi-directional DC motor; a gear reducer connected to the DC motor; a pulley mounted on an output of the gear reducer; an anti-back drive brake mounted on the output of the gear reducer; a reel wound with cable; a second pulley attached to the reel wound with cable; a belt for connecting the pulley and the second pulley; a water measuring device attached to an end of the cable wound on the reel; at least one shaft encoder attached to the motor for measuring the speed and direction of the motor; a DC power source connected to the DC motor; a microprocessor control electronics module connected to the at least one shaft encoder and the DC motor; and a remote control in communication with the microprocessor control electronics module.

Abstract: In a hoisting device for an elevator, a driving motor is made cylindrical, and a brake system is accommodated radially inwardly of the driving motor. The driving motor and the brake system overlap in a radial direction.

Abstract: A braking device includes a brake wheel, a pair of rotation shafts, a pair of brake arms which is rotatably supported through the rotation shafts, a pair of brake pads arranged at one end of the brake arms and contacting and separating from the brake wheel, and a brake part connected to another end of the brake arms for providing and releasing a braking force of the brake pads. When the centers of the rotation shafts are fulcrums, the centers of contact of the brake pads with the brake wheel are points of action, and the connections between the brake arms and the brake part are power points, the fulcrums, the points of action, and the power points are located in a semicircular area of the brake wheel.

Abstract: The present invention discloses a braking device for a motive winch, mainly having a sectional axle, an elastic member, two engraved chunks, and a clutch base in a retardation compartment of the motive winch; wherein said first engraved chunk is coupled to the sectional axle, having a braking plate being contacted with the frictional surface in the retardation compartment; the elastic member has an appropriate whirling force with respect to the first engraved chuck such that the braking plate of the first engraved chuck tends to press against the frictional surface of the retardation compartment; the second engraved trunk is coupled to the sectional axle and rotates synchronously, such that the first and second engraved chucks are capable of being attached to each other to push the brake plate of the first engraved trunk to generate the braking action on an inclined surface and the clutch base brings a protruded member to rotate, and the protruded members on the two engraved chunks is pushed by the protruded

Abstract: A drive unit has a traction sheave mounted on an end of a drive shaft supported by a bearing that is mounted on an extension of a bearing plate that is part of the motor casing. The traction sheave has an extension that serves as a brake drum. Mounted between the traction sheave and the casing, the brake drum together with first brake arms, second brake arms, first electromagnets, second electromagnets, first compression springs and second compression springs form the braking device of the drive unit. On a top of the bearing plate is a first arm linkage and at the bottom of the bearing plate is a second arm linkage. The force of the first compression spring is transmitted to the brake drum by the first brake arm, the required friction force on the brake drum being generated by a first brake lining mounted on a first brake shoe. The friction force on the second half of the brake is generated analogously.

Abstract: A fully redundant drawworks is provided with two complete and totally independent systems for controlling and powering the drum and drum shaft of the drawworks. Each system broadly comprises at least one source of power (e.g., a motor or engine), a power transmission means, preferably of the gear or chain type, and some means of mechanically coupling the power source, transmission and drum shaft together. Each system may also be provided with a brake means, such as one or more disc, band, electric or water-cooled brakes. In the event that any component of either system fails, the fully redundant drawworks will still have the ability to raise drill pipe from a bore hole and thus avoid the risk of a “stuck” drill pipe.

Abstract: A brake for a hoist gear is provided with a pair of brake shoes for braking a disk to be braked arranged on a winding drum side by pressing both sides of the disk. Floating pin fitting piece portions protrude integrally from a body of a bearing supporting the winding drum. A caliper is attached to the fitting piece portions through floating pins. Axis points of the floating pins are arranged in point symmetry of approximately 180.degree. in respect of an axis point of a push rod inserted into the caliper in order to uniformly contact the disk face.

Abstract: A new and useful winch comprising a cable drum; a motor operatively connected to drive a cable drum; a fall arrestor operatively connected to a cable drum and having no power input requirement and a gear reduction group through which a motor and fall arrestor are operatively connected to a cable drum.

Abstract: A chainless drive winch is provided having a cable cylinder meshing with an orthogonal, cylindrical reduction gearing member. The reduction gearing member may be driven by, for example, an electric motor. A brake is provided operable only when the reduction gearing member is rotated is a direction to lower a load. Limit switches may be provided which are adjustable to alter the distance between them. A trigger finger moving between the limit switches is driven from the cable cylinder. The cable cylinder may be provided with a generally parallel roller to hold turns of cable on the cylinder. The roller may be independently biased at each end so that, when cable is partially unwound from the cylinder, the bias of the roller is enhanced on the remaining turns.

Abstract: A winch device which may be truck-mounted and operated by the truck's 12 volt electrical system utilizes an automotive starting motor that interacts with a large diameter disc-like gear. A brake drum and a winch drum are coaxially associated with one face of the disc gear. A brake cable is slidably wound upon the brake drum. A brake lever is provided to control the tension upon the brake cable with consequent adjustment of braking force. A tether is spirally wound upon the winch drum.

Abstract: A braking mechanism for a winch. The braking mechanism includes a sleeve disposed on a motor shaft. The sleeve has slots at intervals which match and align with the slots in the shaft. The sleeve and the shaft are synchronized by a knob that engages the slots. A sprocket coupler attached to the sleeve has channels along its outer surface. Projections are urged out from the channels to mesh with notches in a gear or sprocket that is disposed on the sprocket coupler. The gear has teeth along the outer circumference, a contact surface and a plurality of spaced apart notches along the inner circumference. The notches are designed to have a gradual compressing and an engaging side such that a force is transmitted against the engaging side to turn the gear when the cable is being unwound. A solenoid having a latch coupled thereto is used to arrest the rotation of the gear. Brake pads engage the contact surface to provide a frictional check on gear movement.

Abstract: A tree stand winch (10) for hoisting items from ground level up to a desired height within a tree or pole comprising a crank wheel (12) having both a hand knob (14) and a power tool adapter (16) mounted thereto for actuating a gear assembly (20). Crank wheel (12) is mounted to one surface of a support plate (28) and mounted to the opposite surface of the support plate (28) is a line spool (30) which rotates in response to the actuation of the gear assembly (20). Additionally, secured to the support plate (28) is a brake and drag mechanism (50) for providing variable resistance to the rotation of the line spool (30). The winch (10) is secured to a user's belt by an attachment mechanism (90) while the user ascends a tree or pole. Once positioned up the tree or pole, the user secures the winch (10) to the tree or pole by the attachment mechanism (90).

Abstract: A tree stand winch (10) for hoisting items from ground level up to a desired height within a tree or pole comprising a crank wheel (12) having both a hand knob (14) and a power tool adapter (16) mounted thereto for actuating a gear assembly (20). Crank wheel (12) is mounted to one surface of a support plate (28) and mounted to the opposite surface of the support plate (28) is a line spool (30) which rotates in response to the actuation of the gear assembly (20). Additionally, secured to the support plate (28) is a brake and drag mechanism (50) for providing variable resistance to the rotation of the line spool (30). The winch (10) is secured to a user's belt by an attachment mechanism (90) while the user ascends a tree or pole. Once positioned up the tree or pole, the user secures the winch (10) to the tree or pole by the attachment mechanism (90).

Abstract: An air lifting and balancing unit including a cylinder, a piston in the cylinder, a ball screw affixed to the piston, a ball nut mounted for rotation on the ball screw, a drum mounted on the ball nut, a chain driven by the drum, and centrifugally actuated brakes mounted on the drum for stopping rotation of the drum when the drum exceeds a predetermined acceleration either due to a loss of load or to a loss of air pressure applied to the piston, and a pneumatic circuit in communication with the cylinder for providing air pressure thereto which applies a force on the piston which is at a substantially constant incremental value in opposition to the force exerted by the load applied to the piston through the chain and the drum and the ball screw regardless of variations in said air pressure to thereby cause the speed of the chain to remain substantially constant.

Abstract: A winch wherein braking is achieved by cam actuation, the cam actuation, in a static condition, frictionally interlocking the drive shaft to the cable drum. A gear reduction mechanism is provided between the shaft and drum and is prevented by such interlocking from producing differential rotation of the drum and thus affects lockup or braking of the drum. The locking mechanism is optimally provided by a stator that is fixed to the drum, the stator providing brake surfaces for the drum having disc brake-like braking action. The stator conducts heat from the end surface thereof to the drum and thus to the atmosphere.

Abstract: A safety mechanism for preventing a cable drum to rotate with overspeed has parallel ratchet wheels which encircle a brake drum. At a periphery of the ratchet wheels are stopping slots wherein a latching pawl is inserted when an overspeed is detected. The slots of the adjacent ratchet wheels are staggered. Thus the braking effect of each ratchet wheel starts at a different point of time.

Abstract: An air lifting and balancing unit including a cylinder, a piston in the cylinder, a ball screw affixed to the piston, a ball nut mounted for rotation on the ball screw, a drum mounted on the ball nut, a chain driven by the drum, and centrifugally actuated brakes mounted on the drum for stopping rotation of the drum when the drum exceeds a predetermined acceleration either due to a loss of load or to a loss of air pressure applied to the piston, and a pneumatic circuit in communication with the cylinder for providing air pressure thereto which applies a force on the piston which is at a substantially constant incremental value in opposition to the force exerted by the load applied to the piston through the chain and the drum and the ball screw regardless of variations in said air pressure to thereby cause the speed of the chain to remain substantially constant.

Abstract: A two-piece sheave assembly is provided for a tire lift/carrier winch. The sheave assembly includes a molded plastic, one-piece sheave component that is molded to include a first sheave side plate, an integral sheave center hub with a cable-wrapping track thereon and optionally an integral annular toothed driven ring gear for mating with a toothed drive gear of the winch. The molded plastic sheave component is attached to a second sheave side plate, which may be metal, to form the two-piece sheave assembly. Apertures for the winch drive shaft and the pivotable cable end fitting are integrally molded in the first sheave component.

Abstract: A power operated drive shaft and brake assembly are coaxially mounted for rotation inside a cable drum which is coupled to the drive shaft through gearing. The brake assembly has an adapter housing and one-way clutch for drivingly connecting the drive shaft and adapter housing during a "cable out" operation. A plurality of brake pads are mounted for movement relative to the brake adapter housing. The brake pads are angularly offset in a non-radial orientation to negate undesired brake drag caused by centrifugal forces while the pads are spring loaded to provide a predetermined braking force to hold a load in place after completion of a winching operation.

Abstract: A winch includes a reversible electrical motor with output shaft which drives a drum through a drive mechanism with multiple sprockets and gears to take up and let out a cable. The output shaft is connected through a one-way bearing to a brake hub. The brake lining on a brake arm is spring biased into engagement with the hub and prevents reverse rotation of the output shaft unless an electrical switch actuator is moved to a reverse position, camming the brake arm out of braking relationship with the hub. The drive mechanism may also be powered manually in the forward direction. If free-wheeling of the drum is desired, a knob is rotated to disconnect a clutch in the drive mechanism.

Abstract: A controller for a drilling rig traveling block is disclosed utilizing an absolute position locator and a processor for employing various operating fixed and variable parameters for controlling the speed of travel of the traveling block. As approach limits are reached in either the ascending or descending mode, the position input enters the calculations so that the traveling block is effectively controlled at high speed while safely avoiding an upward or a downward collision. Operation, once the parameter are inputted, is independent of operator control except for override operation.

Abstract: A hoist apparatus comprising a stationary shaft supported by a support, and a sheave having a cavity with a side opening detachably, and rotatably, mounted on the shaft. A motor stator assembly is mounted on the support member and extends into the inner space through the side opening, and a motor rotor assembly is disposed within the inner space in an electromagnetically inductive relationship with the motor stator assembly. The motor rotor assembly is detachably connected to the sheave by a connecting assembly including a bolt fastening the motor rotor assembly to the sheave.

Abstract: A pair of axially aligned input and output shafts are jornalled from a frame supporting a brake drum about the output shaft and the output shaft mounts two pairs of diametrically opposite brake shoes therefrom spring biased into friction braking relation with the inner surfaces of the drum. One pair of brake shoes are of the self-energizing type to brake the output shaft against rotation in one direction relative to the drum and the other pair of shoes are of the self-energizing type for frictionally braking the shaft against rotation in the other direction relative to the drum. Connecting structure is provided establishing a limited loss motion connection between the shafts and includes control structure to release one pair of the brake shoes responsive to torque input to the input shaft above a predetermined minimum in the first direction and to release the other pair of brake shoes responsive to an equal amount of torque input to the input shaft in the opposite direction.

Abstract: A lightweight frame supports a wheelchair platform for up and down movement between four vertical standards, one at each corner. A lifting mechanism includes a winch supported between two of the standards and connected to the platform by cables which pass over pulleys mounted in an upper cross bar pivotally secured and extending between the two posts with the pivot being offset from the longitudinal axis of the crossbar thereby giving a camming or offset partial rotational movement. The winch includes a one way clutch which is disengaged when the platform is elevated but engages automatically as soon as the platform starts to descend thus locking a brake drum to the winch.

Abstract: A compact, lightweight, electrically powered hoist with a drum used for hoisting or lowering a payload. A vertically oriented reversible motor is controlled by a control pendant with a momentary switch to drive a helical gear reduction and a worm gear reduction. A worm shaft and a drum shaft wind wire rope on a drum. A one-way clutch and a brake on a driven shaft free-wheel during hoisting operations. A clutch and brake hold the payload in a hoisted position. Lowering of the hoisted payload is accomplished by reversal of the motor, and driving a shaft and clutch against the torque of the engaged brake. A wire rope with a swaged fitting is anchored to the drum by engagement in a keyhole. The hoist may be mounted horizontally, vertically or on a ceiling.

Abstract: A cable reeling apparatus particularly useful for reeling and dereeling cable for seismic signal recording operations includes a lightweight frame on which a propulsion unit and drive shaft for a cable spool are supported. The cable spool is permanently mounted on the shaft and includes a removable side flange so that coils of cable may be mounted on and demounted from the spool. The spool hub and flanges are provided with cooperating grooves for receiving flexible strapping wherein the coil of cable may be bound at circumferentially spaced points before removal from the spool and field operations may be carried out without dedicated spools for each cable coil.

Abstract: Pulley hoists are disclosed which provide moving anchor hooks that are suspended by two "pulls" of rope, and which may be fabricated by a single part. Anchor hooks are also disclosed which have multiple, independently movable hook portions so that certain large objects may be moved using a sole power unit having said anchor hooks at either end thereof. The anchor hooks of the present invention are also provided with tension indicator apparatuses and safety apparatuses in the event of the overloading of the device. Safety apparatus and sound alarm apparatus are also provided on the power units of the pulley hoists of the present invention in the event of the overloading of the device.

Abstract: A lift sheave arrangement is disclosed which includes a static shaft and a sheave mounted for rotation about the static shaft. The sheave has a first portion for receiving a cable which is to be connected to a lift car and a second portion which includes a brake on its inner circumference. A motor, the brake and second portion for driving the sheave about the static shaft are arranged in the same plane normal to the shaft. The motor has a plurality of movable magnets and a plurality of stationary magnets. The brake drum of the brake includes part of the magnetic circuit between adjacent magnetic elements in the movable magnetic elements.A magnetic actuator is arranged for allowing movement of the brake to apply the brakes and a sensor is provided for sensing the magnetic flux in the actuator when the actuator is actuated to move the brake so that a control circuit can vary the voltage applied to the actuator to enable the brake to move smoothly under the influence of the actuator.

Abstract: A chain winch 10 having a sprocket wheel 14 of polygonal cross-section with flat faces 32 dimensioned in dependence on the dimensions of a link chain to be used therewith and having pin formations 36 for engaging between or in chain links. The winch includes a self latching pawl 48 engageable with the chain links and a braking mechanism 16 for controlled unwinding when required in use. The winch is simple and inexpensive and the sprocket tolerant of chain dimensions so that it can be used with uncalibrated chain. This winch, amongst other things, has application for permanent fitting to a tire chain for tensioning it on to a tire.

Abstract: A motor-driven cylinder for lifting apparatus has screw means including intermeshed internally and externally threaded screw means by which a load can be moved upwardly and downwardly by the torque of a motor, the motor-driven cylinder including torque transmission means movable in a first direction and a second direction opposite thereto for transmitting the torque of the motor to the screw means. During operation, the torque transmission means is moved in the first direction by the applied torque of the motor causing compression of a spring. When no torque is produced from the motor due to its malfunctioning or due to a lack of electrical power applied to the motor the torque transmission means is moved in the second direction under the restoring force of the compressed spring into a mechanically braked condition. Thus, a compact, integral, low-cost safety device is provided for preventing the lifting apparatus from falling, accidentally, under the force of gravity.

Abstract: A drive release brake assembly for controlling rotation includes a wedge member carried between a pair of substantially planar facing cam plate surfaces by an axial core member. The wedge member is prevented from rotating about the core member and include axially extending, rotatable cylinders which extend into contact with the cam surfaces. When the cam surfaces are aligned, the cylinders ride on the cam surfaces to permit relative rotation between the cam surfaces and the core member. When the cam surfaces are moved out of alignment, the distance between them is less than the axial length of the wedge member, causing the cylinders to wedge tightly between the cam surfaces. Because the wedge member is prevented from rotating relative to the core member, when it is wedged or locked between the cam surfaces, the latter are also prevented from rotating relative to the core member.

Abstract: An apparatus to facilitate lifting of heavy loads. The apparatus provides for a hand operated crank which rotates an input shaft which in turn rotates an output shaft which causes lifting of the load. The load would normally be mounted on a platform or other similar type of supporting structure. The apparatus includes a brake assembly which, upon stopping of supplying of the input torque, the brake assembly would automatically hold the load in its lifted position. Also, if the operator wishes to lower the load, reverse rotation of the input shaft will cause the load to be lowered.