Automatic lap doffing mechanism in Blowroom

The construction of the various parts of the auto lap doffing Mechanism is clearly shown in fig.

Ratchet & pawl is Provided in lap length measuring motion.

A graduated disc is provided along the ratchet. On the graduated disc, a projection is given which rotates with the ratchet the same ratchet shaft, the rack pinion and two shoe projection s1 & s2 are fixed.


The graduated disc and projection in it (lap length measuring motion) is set in such a manner that as soon as the lap attains a required pre-set length, it will start the lap doffing device i.e., projection press the micro switch MC4.

MC4 release the brake and start the rack motor when the brake the released, the lap is detached by speeding up the shell roller (at the time of doffing only) by the operation of separate micro switch.

As the rack motor is started, Rack moves upwards, the rack penion rotates in clockwise direction. As the rack moves upwards, full lap is ejected by ejector arm and will drop on the lap tray. When the racks in the top most position, a pair of loading arm (fixed with rack) will take the spare lap spindle from the reserve position.

As the rack penion rotates in clock wise direction it will press the projection sl ,which operate the micro switch MC2. MC2 is a reversing switch for rack motor. So, the racks moves downwards, loading arm will bring the lap spindle and place it in between two shell roller. When the rack moves in down ward, the rack penion rotates in anti-clockwise direction & press the projection S2/ which operate the microswitch MC3. MC3 putoff the rack motor.

Brake is applied and shell roll motor is put off which speed up, the shell roll at the time of lap doffing only. In the first stage of operation, the graduated disc is reversed & put back to its normal position. The beginning of the new lap sheet is folded by the folding handle and lap is wound around the lap spindle and it is leaded again.

All the above operations are completed with in a few seconds while the machine is continuous to run without any interruption. This makes non-accumulation of material at the dust cages during the lap changing, thus no thick and thin places in the lap. results. The production is also increased by 10% at the same working speed, since the m/c is not stopped for 1 lap changing, High reliability in operation due to the greatly simplified and improved automatic changing.

Thus a uniform and even lap with good compactness is produced in the scutcher. Also work of the operative is reduced, so it is possible for one operative to attend more number of scutcher.