tus neeg nyob hauv Syracuse Joseph Burns tau txais txiaj ntsig los ntawm kev tsim riam serrated hauv 1919. Qhov kev tshoov siab tuaj rau nws thaum siv scallop-edged iav-txiav cuab yeej, tus qauv tsim nws xav tias yuav ua pov thawj muaj txiaj ntsig zoo rau kev txiav khob cij.
Lub khob cij tau tsim thaum twg?
Joseph E. Burns, ib tug neeg nyob hauv Syracuse, tau tsim lub khob cij serrated hauv 1919.
Ntev npaum li cas riam serrated nyob ib puag ncig?
Russ J. Christy nrhiav tau lub tuam txhab Christy Riam hauv Fremont, Ohio, kwv yees 1890, thiab nws yuav tsum raug suav hais tias yog leej txiv ntawm rab riam serrated. Daim duab 1 qhia cov duab kos rau patent no. 414, 973, tawm rau lub Kaum Ib Hlis 12, 1889, rau Christy.
riam serrated feem ntau siv yog dab tsi?
Riam serrated, nrog lawv cov scalloped, toothlike edge, yog qhov zoo rau txiav los ntawm cov khoom noj uas muaj sab nrauv thiab softer sab hauv, xws li lub khob cij crusty. Lub hauv paus ntsiab lus tom qab ib rab riam serrated zoo ib yam li cov saw: Cov hniav ntawm cov hniav tuav thiab ces rip raws li cov riam smoothly slides los ntawm cov zaub mov.
Lub khob cij tau tsim nyob qhov twg?
Burns, ib tug Syracuse tus neeg nyob hauv, tau tsim lub khob cij serrated hauv xyoo 1919. Nws cov hniav grooved txhim kho lub neej ntawm cov neeg ua mov ci thiab cov neeg ua noj ua haus thoob ntiaj teb los ntawm kev ua kom yooj yim rau hlais qhob cij yam tsis muaj squishing. nws. Burns tom qab ntawd mus rau patent lub cuab yeej ntse rau cov hniav zoo nkauj hauv xyoo 1940.
