Patents for B43L 21 - Blackboard or slate-cleaning devices (5,409)
05/1999
05/12/1999CN2318051Y Blackboard brush
05/05/1999CN2317098Y Electric dust collecting blockboard eraser
04/1999
04/28/1999CN2316147Y Dust-absorbing health-protecting blackboard eraser
04/21/1999CN2314952Y Automatic eraser for black board
04/21/1999CN2314949Y Automatic erasing dust-free black board
03/1999
03/31/1999CN2312134Y Dust-suction type blackboard eraser
03/24/1999CN2311372Y Anti-dust wiper
03/24/1999CN2311371Y Dustless chalk eraser
03/10/1999CN2309960Y Dust-suction blackboard eraser
03/10/1999CN2309959Y Light dust-proof blackboard traser
03/03/1999CN2309238Y Dust-removing eraser
02/1999
02/24/1999CN2308517Y Rolling dust removing eraser
02/24/1999CN2308516Y Dust absorbing eraser
02/11/1999WO1999005939A1 Cleaning board
02/10/1999CN2306893Y Sanitary blackboard eraser box
01/1999
01/27/1999CN2305299Y Dust absorption blackboard
01/27/1999CN2305298Y Dustless blackboard
01/20/1999EP0891880A1 Device for wet wipe off of blackboards
01/19/1999CA2127143C Eraser system for stubborn dry erase marks
01/13/1999CN1204587A Blackboard erasing machine capable of collecting chalk dust
01/06/1999CN2302904Y Folding blackboard eraser
01/06/1999CN2302903Y Device for absorbing chalk-dust
01/06/1999CN2302902Y Dust-less blackboard wiper
01/06/1999CN2302901Y Electrical blackboard wiper
01/05/1999US5855442 Combined whiteboard marking pen and eraser
12/1998
12/30/1998CN2302138Y Dust-collecting chalk eraser
12/23/1998CN2301333Y 无尘黑板擦 Clean eraser
12/23/1998CN2301332Y Dust-removing blackboard eraser
12/16/1998CN2300525Y 无尘黑板擦 Clean eraser
12/09/1998CN2299727Y Eraser without chalk dust
12/09/1998CN2299726Y Charging chalk dust absorbing eraser
12/09/1998CN2299725Y Dust-proof eraser
11/1998
11/17/1998US5836038 Magnetic mount dry eraser
11/11/1998CN2296828Y Chalk dust-proof blackboard eraser
10/1998
10/14/1998CN2294174Y Blackboard eraser with electrostatic dust absorbing means
10/14/1998CN2294173Y Miniature and multi-function electric blackboard eraser with absorbing chalk dust means
10/07/1998CN2293461Y Blackboard eraser with means for absorbing the chalk dust
10/07/1998CN2293460Y Automatic cleaning chalk dust blackboard
09/1998
09/30/1998CN2292687Y Chalk dust removal blackboard eraser
09/30/1998CN2292686Y Chalk dust absorbing blackboard eraser
09/30/1998CN2292685Y Multifunctional chalk dust absorbing blackboard eraser
09/23/1998CN2292032Y Dust-suction blackboard eraser
09/23/1998CN2292031Y Electric brush for cleaning blackboard chalk dust
09/16/1998CN2291317Y Rolling-type dust-removing eraser
09/09/1998CN2290486Y Dust absorbing multi-hole eraser
09/09/1998CN2290485Y Ash-proof eraser
08/1998
08/26/1998CN2288855Y Electric dust-removing, dust-absorption, filtering blackboard eraser
08/26/1998CN2288854Y Electric dust absorption blackboard eraser
08/26/1998CN1191181A Electric dust-proof blackboard eraser
08/19/1998CN2288081Y Teaching writing blackboard without generating dust
08/12/1998CN2287577Y Multifunctional dust absorbing blackboard eraser
08/05/1998CN2287090Y Dustless brackboard eraser
07/1998
07/15/1998CN2286110Y Dustproof-blackboard eraser
07/08/1998CN2285719Y 无尘黑板擦 Clean eraser
06/1998
06/03/1998CN2282993Y Dust-collecting blackboard eraser capable of replacing hairbrush
06/03/1998CN2282992Y Electric dust-absorption blackboard eraser
05/1998
05/20/1998CN2281903Y Eraser device for blackboard
04/1998
04/29/1998CN2280013Y Static electricity blackboard eraser
04/23/1998DE19730566C1 Device for wet wiping of wall blackboards used in schools
03/1998
03/25/1998CN2276882Y Dusting blackboard eraser
03/11/1998CN2275952Y Electric blackboard eraser
03/11/1998CN1175509A Dust-proof self-erasing blackboard
03/04/1998CN2275526Y Eraser for absorbing chalk dust
02/1998
02/11/1998CN2274140Y Slide-rail for blackboard eraser
01/1998
01/21/1998CN2272824Y Multifunctional dustless hand-operated blackboard cleaning machine
01/21/1998CN2272823Y Multifunctional dustless motor-driven blackboard cleaning machine
01/21/1998CN2272822Y 粉笔擦 Chalk rub
01/14/1998CN2272376Y Dust-proof eraser for blackboard
01/14/1998CN2272375Y High-effect convenient eraser for chalk
12/1997
12/31/1997CN2271449Y Dust collecting cover of eraser
12/31/1997CN2271445Y Dustless writing training aid
12/10/1997CN2269967Y Chalk dust absorbing blackboard eraser
12/03/1997CN2269320Y Hard resin glue cotton blackboard eraser and blackboard eraser box
11/1997
11/26/1997CN2268638Y Dust collecting blackboard eraser
11/19/1997CN2267953Y 黑板擦擦体装置 Blackboard wipe body apparatus
11/19/1997CN1165499A Writing board
11/12/1997CN2267169Y Dustless blackboard wiper
11/05/1997CN2266522Y Blackboard erazer
11/05/1997CN2266521Y Double-eraser type blackboard
10/1997
10/29/1997CN2265912Y Dustless blackboard eraser
10/29/1997CN2265911Y 吸尘黑板擦 Vacuum eraser
10/22/1997CN2265305Y 黑板擦 Eraser
10/15/1997CN2264678Y Dust-proof eraser
10/15/1997CN2264677Y Enclosed eraser
10/01/1997CN2263591Y Electric eraser
09/1997
09/24/1997CN2263010Y Charging dust-absorption blackboard eraser
09/17/1997CN2262500Y Blackboard without hand to clean
09/10/1997CN2261943Y Dust-removing blackboard eraser
08/1997
08/27/1997CN2260723Y Blackboard eraser
08/19/1997US5658635 Bulletin board and accessory attaching mechanism
08/13/1997CN2259298Y Combined blackboard eraser with dust-absorbing device
08/13/1997CN2259297Y Blackboard eraser with device for absorbing the chalk dust
08/13/1997CN2259295Y Improved wear-resistant electric blackboard
07/1997
07/30/1997EP0786358A1 Writing board
07/22/1997US5649828 Water tank filled with water for erasing and decoloring the marked ink; carbon-free, dustless
07/16/1997CN2257769Y Eraser
07/16/1997CN2257768Y 无尘黑板擦 Clean eraser
07/02/1997CN2257251Y Eraser with means for absorbing chalk dust
07/02/1997CN2257250Y Eraser with dust remover
06/1997
06/25/1997CN2256828Y Blackboard eraser with means for absorbing chalk dust
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