QUESTION $1$

A pneumatic lifting device is to be designed to overcome difference in level between the factory and the store. A schematic

diagram of the required device is shown in Fig Qu$.1.$ Actuators $1\mathrm{.}0,2\mathrm{.}0$ and $3\mathrm{.}0$ are all double acting cylinders. The system

is enclosed in a cage with an interlocking door to prevent accidents.

The sequence is as follows:

The operator can start the sequence manually each time or switch the system to automatic i$.$e once switched on the

system will continue until a STOP push button is pressed. The latter option is useful when the supply of boxes is

regular and continuous.

When the lift is in the initial position i$.$e$.$ cylinder $1\mathrm{.}0$ is completely retracted, the interlocking door is closed and the

start signal is given, a box is allowed on the lift by retracting cylinder $3\mathrm{.}0.$

After a delay of $10$ seconds, cylinder $3\mathrm{.}0$ extends to stop the next box. The delay is the time required for the first box

to be transferred onto the lift.

When there is confirmation that there is a box on the lift, and cylinder $3\mathrm{.}0$ has fully extended, cylinder $1\mathrm{.}0$ extends to

raise the box vertically to the next conveying system.

The forward speed of Cylinder $1\mathrm{.}0$ must be adjustable.

After a delay of $3$ seconds, Cylinder $2\mathrm{.}0$ pushes the box from the lift on to the conveying system.

The piston of cylinder $1\mathrm{.}0$ is only to retract when there is confirmation that cylinder $2\mathrm{.}0$ has fully extended.

Cylinder $2\mathrm{.}0$ retracts when cylinder $1\mathrm{.}0$ has fully retracted and the return of cylinder $1\mathrm{.}0$ must be quick

The cycle is to start when the start push button is pushed again to allow another box on the lift. Limit switches are used

to confirm cylinder positions and presence of a box in the lift.

Design and draw the pneumatic system to control the problem described above.