Samvinna
LIST
FEGURÐ OG VELLÍÐAN
HANDVERK
MENNING OG SAGA
SKEMMTUN
UMHVERFI
MATUR OG DRYKKUR
ÖFUGVERKFRÆÐI
VÍSINDI
ÍÞRÓTTIR
TÆKNI
KLÆÐANLEG TÆKNI
Hearing Protection (Ear Defenders): Rigid Cups on Liquid-Filled Cushions (Shaw & Thiessen, NRC, US 2,801,423, 1957)
Ear muffs that seal well and still stop low-pitched noise. Each ear is covered by a rigid cup on a cushion made of a thin PVC tube, emptied of air and part-filled with liquid. Pressed on, the liquid flows round the whole rim and fits the cushion to the head, yet cannot compress, so the cup does not vibrate as a whole and pass the sound in. A sprung headband with a pad holds the cups on ball joints.
Result: circumaural ear defenders effective against low-frequency noise.
Source: E. A. G. Shaw and G. J. Thiessen (National Research Council of Canada), US 2,801,423 (1957). Unknown: sizes and the attenuation achieved. Picture: the patent drawing.
Miðlungs
Unknown
Leiðbeiningar
1
1
Make the cups
Make the cups
Make two rigid, non-porous cups to go over the ears, of wood, a hard plastic or a light metal such as aluminium. Widen each rim to about the width of the cushion, and make a small hole in the rim for the cushion's filling nipple. Fix a ball joint on the back of each cup. Not given: sizes.
Efni fyrir þetta skref:
Óþekktur efniviður2 bollar
Óþekktur málmur2 ball jointsNauðsynleg verkfæri:
Málmrennibekkur
Óþekkt mál2
2
Make the liquid cushions
Make the liquid cushions
For each cup make an endless tube of thin, pliable but non-stretching plasticised PVC, 0.005 to 0.01 in thick, with a filling nipple. Draw out almost all the air, then fill it with liquid to more than a quarter but well under the whole of its cross-section: enough to reach right round the rim when pressed, not so much that it cannot seal. Fix it on the rim with the nipple in the hole. Ours: water as the liquid. Not given: tube size.
Efni fyrir þetta skref:
PVC-plata1 thin plasticised PVC tube
Vatn1 fillingNauðsynleg verkfæri:
Sprautusett3
3
Fit the headband and wear them
Fit the headband and wear them
Make a resilient headband frame with a sponge-rubber pad at its middle and a wire loop at each end. Through each loop pass a threaded stub from the cup's ball joint, with a washer, and tighten with a wing nut. Put the cups over the ears: the cushions take the shape of the head and seal, while the cups stay still against the low-frequency sound. Ours: spring steel for the frame.
Efni fyrir þetta skref:
Fjaðurstálsvír1 frame and loopsÓþekktur efniviður1 sponge rubber padÓþekktur málmur2 threaded stubs
Flöt skinna2 stykki
Vængjahneta2 stykkiNauðsynleg verkfæri:
KringlunefjatöngEfni
7- 1 sponge rubber padStaðgengill
- 2 threaded stubsStaðgengill
- 1 thin plasticised PVC tubeStaðgengill
- 1 fillingStaðgengill
- 1 frame and loopsStaðgengill
- 2 stykkiStaðgengill
- 2 stykkiStaðgengill
Nauðsynleg verkfæri
4- Staðgengill
- Staðgengill
- Staðgengill
- Staðgengill
Efni úr tengdum teikningum
Þessi teikning býr til
CC0 opinbert ríki
Þessi teikning er gefin út undir CC0. Þér er frjálst að afrita, breyta, dreifa og nota þetta verk í hvaða tilgangi sem er, án þess að biðja um leyfi.
Studdu smiðinn með því að kaupa vörur í gegnum teikningu hans þar sem hann fær þóknun smiða sem seljendur ákvarða, eða búðu til nýja endurskoðun á þessari teikningu og tengdu hana sem tengingu í þinni eigin teikningu til að deila tekjum.