With 360 picks/min on a conventional shuttle loom, what bottom-shaft speed is required?
A 120 rpm
B 180 rpm
C 240 rpm
D 360 rpm
Answer: B. 180 rpm. The bottom shaft makes one revolution for two picks, so 360 picks/min requires 180 rpm.
How can fluctuating weft tension across a shuttleless fabric affect its crimp pattern?
A Raises warp crimp only
B Eliminates fabric contraction
C Fixes every pick length
D Creates uneven crimp distribution
Answer: D. Creates uneven crimp distribution. Variations in weft tension can produce uneven crimp distribution across the woven fabric.
For a 3×1 twill at 200 picks/min, what tappet-shaft speed is needed?
A 50 rpm
B 100 rpm
C 150 rpm
D 200 rpm
Answer: A. 50 rpm. The 3×1 twill shedding cycle spans four picks, so the shaft completes 200 ÷ 4 = 50 cycles per minute.
Which change-wheel tooth count gives 80 PPI on a five-wheel take-up?
A 20 teeth
B 40 teeth
C 25 teeth
D 80 teeth
Answer: C. 25 teeth. For this five-wheel take-up, PPI = 2000 ÷ change-wheel teeth. Therefore, 2000 ÷ 80 = 25 teeth.
The seven-wheel take-up adds a 1.5% allowance. What does it compensate for?
A Lengthwise contraction allowance
B To prevent warp breaks
C To compensate reed width
D To reduce beat-up force
Answer: A. Lengthwise contraction allowance. The small allowance compensates for lengthwise fabric contraction after the cloth leaves the loom.
When warp tension rises in positive let-off, how does the system respond?
A Slows the take-up
B Lowers the backrest
C Tightens ruffle friction
D Feeds extra warp faster
Answer: D. Feeds extra warp faster. The floating backrest senses higher tension; the drive then feeds more warp to bring tension down.
Negative let-off controls beam payout using friction between what two parts?
A Reed friction
B Temple friction
C Chain on beam ruffle
D Warp-reed contact
Answer: C. Chain on beam ruffle. A chain wrapped around the beam ruffle supplies the friction that governs negative let-off.
As a negative let-off beam radius falls 25%, what adjustment preserves warp tension?
A Move weight farther away
B Move weight 25% closer
C Increase chain wrap 25%
D Increase warp speed 25%
Answer: B. Move weight 25% closer. The weight distance from the fulcrum is reduced by the same 25% as the beam radius to maintain the tension balance.
Reducing bumping in automatic shuttle weaving can involve which adjustment?
A Increase take-up rate
B Increase PPI
C Lower warp tension
D Change shedding timing
Answer: D. Change shedding timing. Changing shedding timing is a recognized way to reduce bumping in automatic shuttle weaving.
Greater sley eccentricity makes the sley dwell longer near which position?
A Back centre
B Shuttle box
C Front centre
D Cloth fell
Answer: C. Front centre. Increasing sley eccentricity keeps the sley near the front centre for a longer part of its motion.
Fast-reed timing requires the shuttle to reach the swell at which crank angle?
A 270°
B 250°
C 180°
D 300°
Answer: B. 250°. The shuttle should reach the swell at about 250° and displace it completely by 270°.
Compared with fast-reed, which timing advantage does loose-reed provide?
A More shuttle-flight time
B Less shed opening
C Higher shuttle speed
D Earlier beat-up
Answer: A. More shuttle-flight time. Loose-reed motion gives the shuttle more time to cross the shed, allowing higher loom speed.
Crankshaft rotation reaches the sley through what linkage?
A Ratchet and pawl
B Worm and wheel
C Four-bar linkage
D Chain drive
Answer: C. Four-bar linkage. A crank and connecting arm form a four-bar linkage that gives the sley reciprocating motion.
Shuttle acceleration power follows which combination of mass and loom speed?
A Mass × rpm
B Mass² × rpm
C Mass × rpm²
D Mass × rpm³
Answer: D. Mass × rpm³. The cited shuttle-acceleration relation is proportional to shuttle mass multiplied by loom speed cubed.
If loom speed rises 10% at fixed shuttle mass, how does acceleration power change?
A About 33% increase
B About 10% increase
C About 21% increase
D About 10% decrease
Answer: A. About 33% increase. Power scales with rpm³: 1.1³ = 1.331, or about 33% more.
Increasing rpm on gripper and rapier looms is limited by what?
A Air pressure only
B Sley oscillation and carrier inertia
C Reed count only
D Beam diameter
Answer: B. Sley oscillation and carrier inertia. Sley oscillation amplitude and the inertia of the weft carrier constrain further increases in loom speed.
Positive rapier propulsion handles diverse weft yarns through what capability?
A It removes warp tension
B It inserts from both sides
C Tailored rapier motion profile
D It never contacts yarn
Answer: C. Tailored rapier motion profile. Positive propulsion lets the rapier follow a selected motion profile suited to the weft being inserted.
Gabler rapier heads are unsuitable for weak yarns because they apply what?
A Vigorous abrasive strain
B No warp tension
C High water pressure
D Zero insertion speed
Answer: A. Vigorous abrasive strain. The Gabler head subjects the yarn to abrasion while inserting and unfolding it, which can harm weak, soft yarns.
Dewas rapier heads grip the weft at how many points?
A Two points
B Four points
C Along its length
D One point
Answer: D. One point. The Dewas head grips at one point, avoiding further physical damage to the rest of the inserted pick.
On an air-jet loom, what limits further increases in reed width?
A Shuttle mass
B Air drag over long distance
C Chain friction
D Pirn size
Answer: B. Air drag over long distance. Maintaining enough air drag on the weft over a longer insertion distance limits maximum reed width.
Jet looms differ in motion timing by lacking what?
A Dwell of sley and healds
B Pick insertion
C Warp tension
D Cloth fell
Answer: A. Dwell of sley and healds. Jet looms are associated with the absence of dwell in sley and heald motion.
Fused selvedges are associated with which loom pair?
A Shuttle and projectile
B Rapier and water-jet
C Rapier and air-jet
D Circular and narrow
Answer: C. Rapier and air-jet. The cited loom comparison associates fused selvedges with rapier and air-jet looms.
Strong, firm selvedges are a particular advantage of which loom type?
A Air-jet loom
B Water-jet loom
C Rapier loom
D Shuttle loom
Answer: D. Shuttle loom. A conventional shuttle loom can produce strong, firm selvedges, which can matter for some products.
Multiphase looms raise output potential by forming what simultaneously?
A Larger shuttle
B Multiple sheds simultaneously
C Wider reed
D Extra warp beams
Answer: B. Multiple sheds simultaneously. A multiphase loom can form several sheds at once, creating the potential for much higher output.
Tubular hose stock is produced most directly on which loom type?
A Narrow loom
B Projectile loom
C Shuttle loom
D Circular loom
Answer: D. Circular loom. Circular looms produce tubular fabrics used for products such as hose-pipes and sacks.