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linear actuators

2.1. EMA Linear Actuators

2.1.1.Overview of EMA Linear Actuator Range2.1.1.1.What is EMA Linear Actuator?
EMA is an abbreviation for Electro Mechanical Actuator, which consists of either a trapezoidal or ball lead screw, driven by an electricmotor through spiroid gearing. The screw converts the rotary motion into linear movement. As the screw rotates, the nut extends andretracts the ram, which is attached to the load. 2.1.1.2.The EMA Linear Actuator Range
There are 3 standard EMA models, all available in a right-angle drive configuration.•Intermittent model, incorporating a trapezoidal screw.•Continuous model, incorporating a ball screw•High Speed Continuous model, incorporating a ball screw.Where the standard range does not meet the application specification, special actuators can be designed to meet customers’ specificrequirements. 2.1.1.3.Dynamic Load Capacity and Speed
The dynamic load capacity range is up to 10 kN. A defined range of linear speeds from 135 mm/minute to 5510 mm/minute is available.The speed range is achieved by using a combination of gearbox ratios, screw leads and standard motor speeds. 2.1.1.4.Drives
As standard, the units are available with 240v/415v AC or 24v DC motors, with or without a brake. The type of motors required isdependent on the customer’s application. The motors are mounted to the actuator on a 63C Face Flange Mounting. 2.1.1.5Stroke
Each model can be provided with a stroke length up to the maximum, in compression, shown in the Technical Charts. The stroke is defined by the customer. For a tensile load, greater maximum strokes can be accommodated, depending on the linear speed. Where thestroke required exceeds the maximum shown, or there is a high static load, please contact our Technical Sales Department. 2.1.1.6.Standard Features
•Choice of AC or DC motor drives.•Choice of end fittings: clevis, fork clevis,top plate or screwed end. •Trunnion Mounting.•Limit Switches. 2.1.1.7.Emergency Overload Clutch
The emergency overload clutch is a device, which is mounted on the actuator ram, which will slip when the torque to drive the loadexceeds the limit set. If the load is axially locked, or if a torque greater than the clutch setting is required to move the load, the clutchwill disengage the load from the ram and prevent the motor from overloading the actuator components. Please note that the clutch isan emergency device and should not be used for reversing the actuator direction. 2.1.1.8.Limit Switches
Limit switches are fitted to provide end of stroke or ultimate over travel safety. They are mounted on the outer tube of the actuatorand are tripped by a collar on the ram. They are set at a fixed length defined by the customer (see dimensional page for details).Adjustable Limit Switches can be provided on request, consult Power Jacks. 2.1.1.9.Guiding the Load
Side loads on the actuator ram should be avoided by ensuring that the load is guided. The load guide mechanism should resist thetorque developed at the ram by the screw mechanism. A guided ram can be supplied on request, which utilises a keyway in the innerram, eliminates the need for torsional restraint and therefore allows flexibility in the choice of end fitting. 2.1.1.10.Construction
All units are constructed and finished to suit industrial operating conditions. The actuator gearbox and outer tube are either aluminiumor plated for protection and the ram is zinc plated steel. The actuator is sealed at the ram. 2
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