Helical band actuator
Encyclopedia
A helical band actuator, generally known by the trademark Spiralift, is a complex and specialized linear actuator
used in stage lifts and material handling
lifts. The actuator forms a high-capacity telescoping tubular column (lifting capacities to 25,000 pounds, travel to 40 feet).
s in stage and orchestra lift systems. Hydraulic jacks were the predominant push actuators used in performing arts facilities, but they had their issues.
The piston rods of a hydraulic lift extend below the platform they support by more than the length that the lift travels. For lifts at grade, housings for the rods are often sunk into support holes, known as caissons, that are inaccessible and often complicated by groundwater levels. If placed above ground, the space occupied by the rod housings is unusable. Gagnon’s actuator eliminates caissons and reduces the volume of unusable space below the platform of the lift.
Another significant issue with hydraulic lifts is platform drift, the tendency of a platform to lower due to depressurization of the hydraulic system over time. Helical band actuators do not suffer from platform drift because they are rigid mechanical devices.
Traveling nut screw jacks
and rigid chain actuator
s can also be effective at addressing these issues with hydraulic jacks, and are also used for stage lifts.
. The vertical band spirals up on itself into a stacked helix
, forming the wall of the column, while at the same time, the horizontal band interlocks the continuous spiral seam of the vertical band. When the column lowers, the bands separate and retract into two compact coils. The bands are combined, separated and stored by an assembly located at the base of the column. The result is an efficient (50%-80%) telescoping lifting column.
To incorporate the device into a lift system, multiple helical band actuators are arranged below the lift platform where they are powered by an electric motor
(s) and synchronized transmission
. Helical band actuators require a separate lateral support mechanism, usually provided in the form of guide rails or self-guiding frame, such as a pantograph
(e.g. a scissor lift).
Linear actuator
A linear actuator is an actuator that creates linear motion .Mechanical and hydraulic actuation are the most common methods of achieving the linear motion...
used in stage lifts and material handling
Material handling equipment
Material handling equipment is all equipment that relates to the movement, storage, control and protection of materials, goods and products throughout the process of manufacturing, distribution, consumption and disposal...
lifts. The actuator forms a high-capacity telescoping tubular column (lifting capacities to 25,000 pounds, travel to 40 feet).
Raison d'être
Pierre Gagnon was awarded a US patent for the “Push Actuator” in 1989. Gagnon developed the actuator to substitute hydraulic cylinderHydraulic cylinder
A Hydraulic cylinder is a mechanical actuator that is used to give a unidirectional force through a unidirectional stroke. It has many applications, notably in engineering vehicles.- Operation :...
s in stage and orchestra lift systems. Hydraulic jacks were the predominant push actuators used in performing arts facilities, but they had their issues.
The piston rods of a hydraulic lift extend below the platform they support by more than the length that the lift travels. For lifts at grade, housings for the rods are often sunk into support holes, known as caissons, that are inaccessible and often complicated by groundwater levels. If placed above ground, the space occupied by the rod housings is unusable. Gagnon’s actuator eliminates caissons and reduces the volume of unusable space below the platform of the lift.
Another significant issue with hydraulic lifts is platform drift, the tendency of a platform to lower due to depressurization of the hydraulic system over time. Helical band actuators do not suffer from platform drift because they are rigid mechanical devices.
Traveling nut screw jacks
Jackscrew
A jackscrew is a type of jack which is operated by turning a leadscrew. In the form of a screw jack it is commonly used to lift heavy weights such as the foundations of houses, or large vehicles.-Advantages:...
and rigid chain actuator
Rigid chain actuator
A rigid chain actuator, known variously as a linear chain actuator, push-pull chain actuator, electric chain actuator or column-forming chain actuator, is a specialized mechanical linear actuator used in window operating, push-pull material handling and lift applications...
s can also be effective at addressing these issues with hydraulic jacks, and are also used for stage lifts.
Principle of operation
The telescoping column is formed by a pair of interlocking stainless steel bands. One band has a vertical rectangular profile and the other horizontal, much like an oversized SlinkySlinky
Slinky or "Lazy Spring" is a toy consisting of a helical spring that stretches and can bounce up and down. It can perform a number of tricks, including traveling down a flight of steps end-over-end as it stretches and re-forms itself with the aid of gravity and its own momentum.-History:The toy was...
. The vertical band spirals up on itself into a stacked helix
Helix
A helix is a type of smooth space curve, i.e. a curve in three-dimensional space. It has the property that the tangent line at any point makes a constant angle with a fixed line called the axis. Examples of helixes are coil springs and the handrails of spiral staircases. A "filled-in" helix – for...
, forming the wall of the column, while at the same time, the horizontal band interlocks the continuous spiral seam of the vertical band. When the column lowers, the bands separate and retract into two compact coils. The bands are combined, separated and stored by an assembly located at the base of the column. The result is an efficient (50%-80%) telescoping lifting column.
To incorporate the device into a lift system, multiple helical band actuators are arranged below the lift platform where they are powered by an electric motor
Electric motor
An electric motor converts electrical energy into mechanical energy.Most electric motors operate through the interaction of magnetic fields and current-carrying conductors to generate force...
(s) and synchronized transmission
Transmission (mechanics)
A machine consists of a power source and a power transmission system, which provides controlled application of the power. Merriam-Webster defines transmission as: an assembly of parts including the speed-changing gears and the propeller shaft by which the power is transmitted from an engine to a...
. Helical band actuators require a separate lateral support mechanism, usually provided in the form of guide rails or self-guiding frame, such as a pantograph
Pantograph
A pantograph is a mechanical linkage connected in a special manner based on parallelograms so that the movement of one pen, in tracing an image, produces identical movements in a second pen...
(e.g. a scissor lift).