Loom Shaft Speed Calculation
This problem involves calculating the speed of the cam shaft on a shuttle loom based on the speed of the bottom shaft and the type of weave.
Understanding Shaft Speeds
In textile machinery, different shafts rotate at specific speeds related to the weaving process. The bottom shaft (often the main drive shaft) powers various loom mechanisms. The cam shaft specifically controls the shedding motion (lifting and lowering warp threads) based on the weave pattern.
Weave Pattern and Shaft Ratio
The weave pattern dictates the relationship between the speeds of different shafts. A '2 up 1 down' twill weave requires a specific sequence of shedding operations.
- For a 2/1 twill weave, the ratio between the cam shaft speed and the bottom shaft speed is typically 2:3.
Calculating Cam Shaft Speed
The speed of the cam shaft can be determined using the following formula:
$Cam Shaft Speed = (Ratio Factor) * Bottom Shaft Speed$
In this case, the Ratio Factor is $\frac{2}{3}$.
- Given: Bottom shaft speed = 90 rpm.
- Apply the ratio: Cam Shaft Speed = $\frac{2}{3} \times 90 \text{ rpm}$
- Calculation: Cam Shaft Speed = $2 \times 30 \text{ rpm}$
- Result: Cam Shaft Speed = 60 rpm.
Therefore, the speed of the cam shaft is 60 rpm.
Important Questions from FABR Loom Mechanisms Shedding
- Group I lists the components of the weaving machine and Group II lists their functions. Match the component with its function.
Group I Group II P Conjugate/matched cams 1 Driving the cloth roller with slip
driveQ Worm and worm wheel 2 Continuous positive take up
motionR Friction clutch device 3 Motion of sley in rapier loom S Lease rod 4 Separation of the warp sheet
forming the shed Amongst the following, the correct condition(s) that will reduce bumping during weaving is/are
- Group I lists weaving machine related parameters and Group II contains the shortcomings of these parameters. Match the machine related parameter with its shortcoming.
Group I Group II P. Variable heald staggering 1. Not favourable for heavy fabric Q. High eccentricity ratio 2. Reduction in shed height R. Fixed heald staggering 3. Reduction of sley dwell S. Late shedding 4. Higher vibration in weaving machine Group I gives a list of loom motions and Group II contains loom systems. Match the motion from Group I with the corresponding system from Group II.
Group I Group II P. Shedding 1. Matched cam Q. Picking 2. Seven wheel R. Beat-up 3. Rapier S. Take-up 4.Jacquard Determine the correctness or otherwise of the following Assertion [a] and Reason [r]
Assertion: In shuttle loom, late shedding is preferred for filament weaving.
Reason: In late shedding, the timing of shed dwell matches with the timing of shuttle travel through the shed, and therefore, it minimises the rubbing of warp yarns.
