Abstract: A vacuum lift device comprising a lift tube which is able to contract and expand in an upward and downward direction, and a lift tube expansion control valve controlling the opening areas of the atmospheric openings of the lift tube. A hovering control valve controlling the flow area between the second atmospheric opening and the interior of the lift tube is provided. The lift tube expansion control valve is normally positioned at a position such that is completely covers the first atmospheric opening, and the second atmospheric opening is open to the outside space. At this time, the level of vacuum in the lift tube is adjusted by the hovering control valve so that an object to be lifted is maintained at a desired height.

Abstract: An actual operating time indicator includes: a lifting motor for lifting a load up/down; a power detection unit for detecting an input power based on a current and a voltage supplied to the motor, and converting the input power into a first voltage proportional to the input power; a voltage-to-periodic pulse conversion unit connected to the power detection unit for receiving the first voltage and converting the first voltage into the periodic pulse proportional to the first voltage; a counter unit connected to the voltage-to-periodic pulse conversion unit for counting and integrating the periodic pulse to obtain an integrated power; and a display operatively connected to the counter unit for indicating the integrated power as an actual operating time of the motor.

Abstract: An electric hoist comprising an electric motor and a sheave driven by the electric motor via a reduction gear. The reduction gear comprises a pair of helical gears meshing with each other. One of the helical gears is axially movably arranged on a shaft and is moved in the axial direction thereof when there is a load on the load chain supported by the sheave, and when the axial movement of the movable helical gear is detected by a sensor, the speed of rotation of the electric motor is automatically changed from a higher speed to a lower speed.

Abstract: The invention relates to a vertical indicator unit for measurement comprising placing a float in a vessel filled with a liquid, supporting the vessel with an external supporting frame, securing a doughnut-like magnet integrally with the outside of the lower end portion of the float, connecting a vertical supporting rod to a hinge contact point at the lower end of the external supporting frame, securing a separate funnel-like doughnut magnet to the upper end head portion of the vertical supporting rod, reversely polarizing both the magnets for diamagnetically repulsively maintaining both the magnets from each other at a certain air space, inserting the head portion of the vertical supporting rod into the inner space of the upper vessel, and vertically maintaining the vertical supporting rod with respect to a predetermined position of the lower portion of the supporting frame by diamagnetism of the doughnut-like magnet of the float and the funnel-like magnet provided in the head portion of the vertical supporti

Abstract: An operating device for an electric chain block having an electric motor for a raising and lowering operation comprises a cylinder body interposed between one end of a chain for raising and lowering an object and a hook for hanging the object, a cylindrical grip fitted on the cylinder body and slidable upwardly and downwardly over predetermined distances relative to the cylinder body.

Abstract: An operating device for an electric hoist, comprises a switch box and a cylindrical body connected to a lower end of a chain depending from a main body of the electric hoist for lifting a load. To a lower end of the cylindrical body is connected a lower hook hanging the load to be lifted. The operating device further comprises a grip vertically slidably fitted on the cylindrical body and kept at a substantially mid position of a slidable distance of the grip relative to the cylindrical body, raising and lowering switches for raising and lowering the load provided in the cylindrical body to be actuated by a striker fixed to the grip, high and low speed alteration switch provided in the switch box for changing high and low operating speeds of the electric hoist, and a stepless speed adjusting device for adjusting the high and low operating speeds of the electric hoist in a stepless manner.

Abstract: A stepless speed change electric chain block includes a DC motor for driving a load sheave. The chain block comprises a phase control circuit having a variable resistor, a capacitor, a two-way trigger diode, and a triode AC switch for receiving alternating current from alternating power source to control it in phase, a full-wave-rectifier for receiving alternating current controlled in phase in the phase control circuit to convert it into direct current which is supplied into the DC motor, and mechanical brake means provided in a transmission between the DC motor and the load sheave for braking rotation of the load sheave in a winding-off direction. With this arrangement, as the speed setting for winding operation is effected only by the phase control circuit, so that the constitution of the block is simplified and inexpensive in comparison with the prior art. All the supplied power is effectively utilized for operating the chain block.

Abstract: An operating device for an electric hoist having a DC motor for raising and lowering an object, comprises a low speed adjusting setting unit (VR1) and a high speed adjusting setting unit (VR2) provided in a control box of the hoist. The operating device further comprises in the control box a two-step push-button switch (PB-U) for the raising operation for switching over the low speed adjusting setting unit and the high speed adjusting setting unit to connect either of the units (VR1 and VR.sub.2) to a speed-change control circuit by pushing the two-step push-button switch (PB-U) to either of first and second step positions, and a two-step push-button switch (PB-D) for the lowering operation for switching over the low speed adjusting setting unit (VR1) and the high speed adjusting setting unit (VR2) to connect either of the units to the speed-change control circuit by pushing the two-step push-button switch (PB-D) for the lowering operation to either of first and second step positions.

Abstract: An electric chain block includes a driving shaft connected to a rotating shaft of an electric motor, and a driving gear provided on the driving shaft, and further includes an intermediate driven gear in mesh with the driving gear, a torque limiter and a mechanical brake assembly between the driving shaft and a load sheave.

Abstract: A hoist includes a shaft driven by external force, a driving shaft connected to the shaft, a reduction gear train for transmitting rotation of the driving shaft to a load sheave, a mechanical brake assembly in the reduction gear train, and an overload safety device having a clutch mechanism capable of transmitting torque larger in driving said load sheave in a winding-off direction than that in a winding-up direction.

Abstract: An idling device is able to bring into an idling condition a lever hoist including a change gear provided on driving member threadedly engaged on a driving shaft for driving a sheave winding-up thereabout a chain or rope for a load, an operating lever rockably driven by a hand, winding-up and winding-off driving pawls engageable with teeth of the change gear and changeable in response to the purpose of hoisting or lowering the load, and a braking assembly for preventing the change gear from being driven by a gravity of the load and adapted to be clamped and released by rotative movement of the driving member relative to said driving shaft.

Abstract: An electric hoist includes an electric motor, a driving shaft connected to a rotor shaft of said electric motor, a reduction gear train for transmitting rotation of the driving shaft to a load sheave, and a mechanical brake assembly in the reduction gear train.

Abstract: An electric hoist includes an electric motor, a driving shaft connected to a rotor shaft of said electric motor, a reduction gear train for transmitting rotation of the driving shaft to a load sheave, and a mechanical brake assembly in the reduction gear train. According to the invention between the driving shaft and the rotor shaft of the motor is arranged an overload safety device comprising a support member fixed to the rotor shaft, a retainer member fitted onto the driving shaft, and a disc arranged between the support and retainer members through friction plates and having a one-way clutch. The one friction plate between the retainer plate and the disc has larger friction transmission force than that of the other friction plate between the support member and the disc.

Abstract: A hoist includes a shaft driven by external force, a driving shaft connected to the shaft, a reduction gear train for transmitting rotation of the driving shaft to a load sheave, and a mechanical brake assembly in the reduction gear train. According to the invention in the reduction gear train is arranged an overload safety device comprising a driven gear having a one-way clutch and rotatively driven by the driving shaft and radially inward and outward dual friction plates located between the driven gear and an element of the mechanical brake assembly so as to transmit torque through the radially outward friction plates in winding-up and through both the radially inward and outward friction plates in winding-off. With this arrangement, the electric hoist according to the invention is able to automatically prevent lifting, lowering and dragging a load under overload condition, and enables the once lifted load to be securely lowered irrespective of its light or heavy weight.

Abstract: An idling device is able to bring into an idling condition a lever hoist including a change gear provided on driving member threadedly engaged on a driving shaft for driving a sheave winding-up thereabout a chain or rope for a load, an operating lever rockably driven by a hand, winding-up and winding-off driving pawls engageable with teeth of the change gear and changeable in response to the purpose of hoisting or lowering the load, and a braking assembly for preventing the change gear from being driven by a gravity of the load and adapted to be clamped and released by rotative movement of the driving member relative to said driving shaft.

Abstract: An idling device is able to bring into an idling condition a lever hoist including a change gear provided on driving member threadedly engaged on a driving shaft for driving a sheave for winding-up a chain or rope for a load, an operating lever rockably driven by a hand, winding-up and winding-off driving pawls engageable with teeth of the change gear and changeable in response to the purpose of hoisting or lowering the load, and a braking assembly for preventing the change gear from being driven by a gravity of the load and adapted to be clamped and released by rotative movement of the driving member relative to said driving shaft.

Abstract: An idling device is able to bring a lever hoist into an idling condition including a change gear provided on driving member threadedly engaged on a driving shaft for driving a sheave for winding-up a chain or rope for a load, an operating lever rockably driven by a hand, winding-up and winding-off driving pawls engageable with teeth of the change gear and changeable for hoisting or lowering the load, and a braking assembly for preventing the change gear from being driven by the gravitational force of the load and adapted to be clamped and released by rotative movement of the driving member relative to the driving shaft.

Abstract: An idling device is able to bring into an idling condition a lever hoist including a change gear provided on driving member threadedly engaged on a driving shaft for driving a sheave for winding-up a chain or rope for a load, an operating lever rockably driven by a hand, winding-up and winding-off driving pawls engageable with teeth of the change gear and changeable in response to the purpose of hoisting or lowering the load, and a braking assembly for preventing the change gear from being driven by a gravity of the load and adapted to be clamped and released by rotative movement of the driving member relative to said driving shaft. According to the invention the idling device comprises a stopper fixed to the driving shaft and a manually operatable knob fitted on and rotatably and axially slidably relative to the driving shaft between the stopper and the driving member and provided with engagement protrusions adapted to be engaged in recesses formed in the driving member.

Abstract: A lever hoist comprises a change gear provided in a driving shaft for driving a sheave for winding-up a chain or rope for a load, an operating lever rockably driven by a hand, winding-up and winding-off driving pawls engageable with teeth of the change gear and changeable in response to the purpose of hoisting or lowering the load, and a braking assembly for preventing the change gear from being driven by a gravity of the load and having a spring for releasing the braking assembly. According to the invention the lever hoist further comprises a brake spring control member rotatably fitted on the driving shaft, a brake clamping spring arranged between the driving member and the brake spring control member, and a direction change transmission mechanism for transforming rotation of the brake spring control member into axial urging force of the brake clamping spring.