| Patents for B43L 21 - Blackboard or slate-cleaning devices (5,409) |
|---|
| 12/18/1991 | CN2090780U Portable dust obsorption blackboard eraser |
| 12/18/1991 | CN2090779U Dust-preventing blackboard eraser |
| 12/18/1991 | CN2090644U Bidirectional dust-collecting multipurpose brush |
| 12/17/1991 | US5072483 Eraser |
| 12/11/1991 | CN2090334U Multipurpose electric dust-absorbing chalk eraser |
| 12/11/1991 | CN2090333U Dust-collecting blackboard eraser |
| 11/13/1991 | CN2088490U Dust-free blackboard eraser |
| 10/30/1991 | CN2087572U Blackboard eraser with dust collector |
| 09/18/1991 | CN2084886U Automatic dust-collecting eraser |
| 09/11/1991 | CN2084431U 吸尘式粉笔擦 Wipe chalk dust type |
| 08/28/1991 | CN2083546U 黑板 Blackboard |
| 08/14/1991 | CN2082685U Eraser with dust catcher |
| 08/14/1991 | CN2082684U Automatic blackboard eraser |
| 07/24/1991 | CN2081353U Wheel dust-collecting eraser |
| 07/24/1991 | CN2081352U Automatic dust-collected eraser |
| 07/10/1991 | CN2080472U Electric chalk dust absorbing blackboard eraser |
| 07/10/1991 | CN2080471U Rolling automatic chalk dust collecting blackboard eraser |
| 07/03/1991 | CN1052633A Electric non-dust eraser |
| 06/26/1991 | CN2079575U Blackboard wiper with mechanically absorbing chalk dust function |
| 06/26/1991 | CN2079574U Roll type blackboard wiper |
| 06/26/1991 | CN2079573U Blackboard wiper with absorbing chalk dust function |
| 06/26/1991 | CN2079572U Machine for wiping blackboard |
| 06/19/1991 | CN2079126U Dust-collecting blackboard eraser |
| 05/29/1991 | CN2077804U 粉笔灰尘收集盒 Chalk dust collection box |
| 05/22/1991 | CN2077382U Blackboard eraser with dust collecting |
| 05/22/1991 | CN2077381U Blackboard eraser with dust collecting |
| 05/15/1991 | CN2076930U Non-dust eraser |
| 05/15/1991 | CN2076929U Non-power source dust-collecting eraser |
| 05/15/1991 | CN2076928U Multi-functional eraser with handle |
| 05/08/1991 | CN2076500U Dusting blackboard eraser |
| 04/24/1991 | CN2075598U Words erasing machine |
| 04/17/1991 | CN2075151U Brush changeable non-power precipitating blackboard eraser |
| 04/17/1991 | CN2075150U Precipitating blackboard eraser |
| 04/17/1991 | CN2075149U Electrostatic precipitating blackboard eraser |
| 04/10/1991 | CN2074714U Dust suction blackboard eraser |
| 04/03/1991 | CN2074249U Rolling chalk dust-absorbing eraser |
| 03/20/1991 | CN2073371U Electric blackboard eraser with dust absorbing function |
| 03/20/1991 | CN2073370U Blackboard eraser with dust absorpting air-sack |
| 03/20/1991 | CN2073369U 手提式电动黑板擦 Portable electric eraser |
| 03/20/1991 | CN1050002A Electrical dust-removing blackboard eraser |
| 03/06/1991 | CN2072484U Aspirating eraser |
| 02/06/1991 | CN2070683U Blackboard eraser with absorbing chalk dust |
| 01/30/1991 | CN1048821A Fully automatic blackboard for handwriting, picture drawing and sound and picture coopreation |
| 01/09/1991 | CN2068919U Multi-functional blackboard eraser with dust collector |
| 12/26/1990 | CN2068057U Rolling eraser |
| 12/12/1990 | CN2067225U Small-size electric dust catching blackboard wiper |
| 11/21/1990 | CN2065990U Eraser with dust absorption function |
| 11/14/1990 | CN2065569U Dustless blackboard eraser |
| 11/14/1990 | CN2065454U Multi-functional cleaning brush |
| 11/07/1990 | CN2065152U Dust-absorbing eraser |
| 10/24/1990 | CN2064310U Eraser without dust |
| 10/03/1990 | CN2063086U Chalk eraser absorbing chalk dust by filtering |
| 09/12/1990 | CN2061903U Blackboard eraser with chalk dust absorbing function |
| 08/22/1990 | CN2060736U Blackboard eraser with means automatically absorbing the chalk dust |
| 08/22/1990 | CN2060735U Blackboard eraser with powder-like waste collecting function |
| 08/21/1990 | CA1272859A1 Blackboard eraser |
| 08/15/1990 | CN2060404U Rotary dust-collecting eraser |
| 08/01/1990 | CN2059878U Dust-proof blackboard eraser |
| 07/17/1990 | US4941225 Automatic chalk-powder collecting device for blackboard eraser |
| 07/03/1990 | US4937910 White board eraser |
| 06/20/1990 | CN2058383U Blackboard eraser with dust catcher |
| 06/20/1990 | CN2058382U 防尘黑板擦 Eraser dust |
| 06/13/1990 | CN2058146U Non-electric dust catching blackboard eraser |
| 06/13/1990 | CN2058145U Non-roller type rotary blackboard erasing device |
| 05/30/1990 | CN2057622U Electric dust-absorbing eraser |
| 05/16/1990 | CN2057147U Electrostatic dust adsorption blackboard eraser |
| 05/03/1990 | DE3936978A1 Window cleaning appliance - with rubber wiper strip above block of viscose sponge |
| 04/25/1990 | CN2056391U Blackboard rubber with suction for chalk powder |
| 04/11/1990 | CN2055779U Blackboard eraser with dust catcher |
| 04/11/1990 | CN2055778U Blackboard eraser with dust catcher |
| 04/04/1990 | CN2055450U Electric dust collecting eraser |
| 03/28/1990 | CN2055098U Moist dustproof blackboard eraser |
| 03/07/1990 | CN2053991U Blackboard eraser with means for absorbing chalk dust |
| 02/28/1990 | CN2053580U Dust-collecting blackboard eraser |
| 02/21/1990 | CN2053155U Dust-free eraser |
| 02/21/1990 | CN1039763A Nondust chalk eraser |
| 02/14/1990 | CN2052726U Electric dust-cataching blackboard eraser |
| 02/14/1990 | CN2052725U Multipurpose dust-collecting electric blackboard eraser |
| 02/07/1990 | CN2052355U Tape-type rotary blackboard |
| 01/31/1990 | CN2051898U Chalk dust-collecting blackboard eraser |
| 01/24/1990 | CN2051573U Blackboard eraser with dust catcher |
| 01/17/1990 | CN2051167U 集尘板擦 Eraser dust |
| 01/17/1990 | CN2051166U Dust collecting blackboard brush |
| 01/03/1990 | CN2050389U Dust-collecting eraser |
| 01/03/1990 | CN2050388U Blackboard eraser with dust removing |
| 11/29/1989 | CN2048431U Caterpillar blackboard brush with dust pan |
| 11/29/1989 | CN2048430U Automatic blackboard brush without dust |
| 11/22/1989 | CN2048028U Electric blackboard eraser with dust-proof function |
| 11/22/1989 | CN2048027U Multi-function electric blackboard eraser |
| 11/08/1989 | CN2047230U Vertical miniature dust-arrestor of midget drawing erasing device |
| 11/01/1989 | CN2046818U Collector of chalk powder |
| 10/25/1989 | CN2046449U Dust aspirating rubber for blackboard |
| 10/25/1989 | CN2046448U Blackboard rubber with self aspirating without adding any source of energy |
| 10/25/1989 | CN2046447U Blackboard rubber with dust absorbing function |
| 09/27/1989 | CN2044938U Magnetic blackboard eraser |
| 09/27/1989 | CN1035798A Dust-collecting eraser |
| 09/13/1989 | CN2044213U Open and close type dust-proof blackboard erazer |
| 09/13/1989 | CN2044143U Dust cleaning brush for blackboard and furniture |
| 09/06/1989 | CN2043923U Friction chalk powder absorbing eraser without power source |
| 08/23/1989 | CN2043192U Blackboard eraser with dust catcher |