14-08-2012, 01:34 PM
LEAD SCREW OPERATED SCISSOR LIFT
IEC COLLEGE OF ENGINEERING AND TECHNOLOGY.pptx (Size: 202.75 KB / Downloads: 127)
INTRODUCTION
A scissor lift is a type of platform which can usually only move vertically.
The mechanism to achieve this is the use of linked, folding supports in cris cross ‘X’ pattern.
The upward motion of the lift can be achieve by the application of pressure to the out side of the lowest set of supports, elongating the crossing pattern, and propelling the work plat form vertically .
The plat form may also have an extending ‘bridge’ to allow closer access to the work area.
Pantograph mechanism of scissor lift
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. If a line drawing is traced by the first point, an identical, enlarged or miniaturized copy will be drawn by a pen fixed to the other.
Because of their effectiveness at translating motion in a controlled fashion, pantographs have come to be used as a type of motion guide for objects large and small. A common example of the use of a pantograph assembly as mechanical guide frame is the extension arm of an adjustable wall-
Why we are using lead screw?
As our project is the prototype of the models that are used in the industries so instead of actuators we are using the lead screw.
With the help of lead screw and its movement the arms of the lift moves up and down.
A lead screw is such a part which when rotates gives the linear motion.
Lead screw is the devices which can transmit the linear motion by the action of rotary motion. The speed of the screw depends upon the motor connected to it.
Advantages of scissor lift
1) Scissor lifts can help operators to reach areas that might otherwise be inaccessible. Larger models can extend to a height of 18.8 meters (62 feet)
2) Scissor lifts are so simple to operate and move that they reduce fatigue in operators, increasing levels of production.
3) Scissor lifts eliminates Repetitive strain injury (RSI) by avoiding the need to bend and stretch repeatedly.