Sheave (mechanical)
Encyclopedia
A sheave is a wheel or roller with a groove
along its edge for holding a belt
, rope
or cable
. When hung between two supports and equipped with a belt, rope or cable, one or more sheaves make up a pulley
. The words sheave and pulley are sometimes used interchangeably.
A sheave can also refer to a pulley which has an adjustable operating diameter for use with a belt
. This is accomplished by constructing the pulley out of several pieces. The two main "halves" of the pulley can be moved closer together or farther apart, thus altering the operational diameter. The usual construction is some sort of locking collar or set screws to secure the components, one half with a threaded central shaft and one half with a threaded center. By rotating the components one can "screw" the parts closer or farther apart. Thus changing the distance between the two halfs and allowing the belt
to ride higher or lower in the grove. The adjustments are limited to a specific range of size and is not infinitely adjustable. The sheave is thus purchased for the appropriate application. The adjustability of the sheave allows for the correction of speed of the driven load from a fixed speed driver, or for the adjustment of the load place on the driver. Thus an electric motor can have the load placed on it corrected up or down to match its rated capacity. A typical application would be a Belt Driven Blower Wheel with fixed pulley driven by an electric motor with a sheave. The sheave is adjusted for Max Load Amps of the motor to attain full capacity. Conversely the sheave can be adjusted "down" to lower the amount of air moved or static pressure attained by the blower.
Groove (machining)
In manufacturing or mechanical engineering a groove is a long and narrow indentation built into a material, generally for the purpose of allowing another material or part to move within the groove and be guided by it. Examples include:...
along its edge for holding a belt
Belt (mechanical)
A belt is a loop of flexible material used to link two or more rotating shafts mechanically. Belts may be used as a source of motion, to transmit power efficiently, or to track relative movement. Belts are looped over pulleys. In a two pulley system, the belt can either drive the pulleys in the...
, rope
Rope
A rope is a length of fibres, twisted or braided together to improve strength for pulling and connecting. It has tensile strength but is too flexible to provide compressive strength...
or cable
Wire rope
thumb|Steel wire rope Wire rope is a type of rope which consists of several strands of metal wire laid into a helix. Initially wrought iron wires were used, but today steel is the main material used for wire ropes....
. When hung between two supports and equipped with a belt, rope or cable, one or more sheaves make up a pulley
Pulley
A pulley, also called a sheave or a drum, is a mechanism composed of a wheel on an axle or shaft that may have a groove between two flanges around its circumference. A rope, cable, belt, or chain usually runs over the wheel and inside the groove, if present...
. The words sheave and pulley are sometimes used interchangeably.
A sheave can also refer to a pulley which has an adjustable operating diameter for use with a belt
Belt (mechanical)
A belt is a loop of flexible material used to link two or more rotating shafts mechanically. Belts may be used as a source of motion, to transmit power efficiently, or to track relative movement. Belts are looped over pulleys. In a two pulley system, the belt can either drive the pulleys in the...
. This is accomplished by constructing the pulley out of several pieces. The two main "halves" of the pulley can be moved closer together or farther apart, thus altering the operational diameter. The usual construction is some sort of locking collar or set screws to secure the components, one half with a threaded central shaft and one half with a threaded center. By rotating the components one can "screw" the parts closer or farther apart. Thus changing the distance between the two halfs and allowing the belt
Belt (mechanical)
A belt is a loop of flexible material used to link two or more rotating shafts mechanically. Belts may be used as a source of motion, to transmit power efficiently, or to track relative movement. Belts are looped over pulleys. In a two pulley system, the belt can either drive the pulleys in the...
to ride higher or lower in the grove. The adjustments are limited to a specific range of size and is not infinitely adjustable. The sheave is thus purchased for the appropriate application. The adjustability of the sheave allows for the correction of speed of the driven load from a fixed speed driver, or for the adjustment of the load place on the driver. Thus an electric motor can have the load placed on it corrected up or down to match its rated capacity. A typical application would be a Belt Driven Blower Wheel with fixed pulley driven by an electric motor with a sheave. The sheave is adjusted for Max Load Amps of the motor to attain full capacity. Conversely the sheave can be adjusted "down" to lower the amount of air moved or static pressure attained by the blower.