| Patents for B43L 21 - Blackboard or slate-cleaning devices (5,409) |
|---|
| 08/16/1989 | CN2042803U Cleaning eraser |
| 08/16/1989 | CN2042802U Automatic dust collecting evaser |
| 08/16/1989 | CN2042801U Foam-rubber eraser with dust collecting function |
| 08/09/1989 | CN2042421U Hand-driving non-dust blackboard eraser |
| 07/12/1989 | CN2040855U 吸尘黑板擦 Eraser dust |
| 07/05/1989 | CN2040444U Chalk powder absorbing eraser |
| 06/21/1989 | CN2039634U Automatic dust-removing blackboard eraser |
| 04/05/1989 | CN2035325U Plane-screw dust-suction eraser |
| 03/15/1989 | CN2034132U Dedusting eraser |
| 03/08/1989 | CN2033760U Electrostatic dust absorption eraser |
| 03/08/1989 | CN2033759U Glove type eraser |
| 03/01/1989 | CN2033344U Large-scale push-type machine blackboard |
| 03/01/1989 | CN1031349A Dust-absorbing blackboard |
| 02/22/1989 | CN2032947U Dust-collecting eraser |
| 02/22/1989 | CN2032946U Automatic wipping dustless eraser |
| 02/15/1989 | CN2032551U Rotary dust-free blackboard |
| 02/08/1989 | CN2032150U Blackboard eraser with duster |
| 01/25/1989 | CN2031362U Electrostatic dedusting blackboard eraser with cleaning agent |
| 01/25/1989 | CN2031361U Dust-absorbing blackboard eraser |
| 01/18/1989 | CN2030952U Electric blacboard eraser with chalk dust absorbing |
| 01/18/1989 | CN2030854U Miniature vacuum cleaner |
| 01/11/1989 | CN2030556U Dust-free blackboard eraser |
| 12/21/1988 | CN88201190U 可动式黑板 Movable blackboard |
| 12/07/1988 | CN87213978U Automatic guide rail aspirating eraser |
| 11/16/1988 | CN87209703U Auto-wiping blackboard |
| 11/09/1988 | CN88212324U Dust collector blackboard brush |
| 09/14/1988 | CN87211317U High efficient self absorbent ash blackboard eraser |
| 09/14/1988 | CN85203081U Electric vacuum eraser for blackboard |
| 09/07/1988 | CN87204788U Combination type eraser for blackboard |
| 07/20/1988 | CN87216170U Writing board for teaching |
| 07/20/1988 | CN87212054U Automatic dust exhaust eraser for blackboard |
| 07/06/1988 | CN87210581U Electronic dust-catching eraser |
| 06/15/1988 | CN87204528U Dust remover for blackboard eraser |
| 06/15/1988 | CN86210557U Blackboard eraser with dust catcher |
| 06/08/1988 | CN87212721U Automatic ac dust-absorption eraser |
| 06/08/1988 | CN87211939U Dust-proof eraser for blackboard |
| 05/10/1988 | US4742594 Blackboard eraser |
| 03/23/1988 | CN87206880U Dedusting blackboard eraser |
| 03/09/1988 | CN86209282U Revolving roller electric blackboard-cleaning device |
| 03/02/1988 | CN87201471U Reducing dust eraser |
| 03/02/1988 | CN85102015B Auto-erasing motor-driven blackboard |
| 02/17/1988 | CN86104910A Dust absorbing chalk-eraser without electric source |
| 02/03/1988 | CN87207528U Magnetic writing apparatus |
| 02/03/1988 | CN87205976U Writing board wiper with dust collector |
| 01/13/1988 | CN87204000U Chalk dust-absorbing blackboard eraser |
| 01/06/1988 | CN87202803U Sutomatic blackboard eraser |
| 12/30/1987 | CN87208436U Blackboard eraser with collectting device for chalk powder |
| 12/23/1987 | CN87100578A Electromagnetic writing plate |
| 12/23/1987 | CN85204933U Strip type movable blackboard having auto-cleaning function |
| 12/16/1987 | CN86205606U Blackboard capable of changing face automatically and wiping original handwriting |
| 12/02/1987 | EP0247041A1 Dust extractors |
| 11/25/1987 | CN87201337U Axial-flow type powder-absobing electric eraser |
| 11/18/1987 | CN85205650U Movable dirt-free blackboard with automatic cleaner |
| 11/04/1987 | CN87200153U Chalk powder cleaner for eraser |
| 10/31/1987 | CN86209165U Revolving blackboard |
| 10/31/1987 | CN86207531U Reelable blackboard |
| 10/21/1987 | CN87200365U 两用粉笔盒 Dual ChalkBox |
| 10/14/1987 | CN87202014U Dust-catching eraser |
| 10/14/1987 | CN86102246A Cirele-round self-erasing dust-free blackboard |
| 10/07/1987 | CN86209589U Electric dustless eraser for blackboard |
| 10/06/1987 | US4697301 Blackboard rubber made of, or including, metal |
| 10/03/1987 | CN86206556U Blackboard eraser |
| 09/30/1987 | CN85108104A 电动黑板擦 Electric eraser |
| 09/23/1987 | CN86207969U Eraser |
| 09/09/1987 | CN86209858U Powder-absorption eraser |
| 09/02/1987 | CN86206126U Dustless magnetic erasor |
| 08/19/1987 | CN86207405U Electric aspirating eraser |
| 08/11/1987 | CA1225477A1 Eraser for electronic blackboard |
| 07/01/1987 | CN86206297U Electric dust-sucking plastering machine |
| 07/01/1987 | CN86205051U Powder-sucking eraser |
| 06/02/1987 | US4670751 Eraser for electronic blackboard |
| 05/27/1987 | CN86207341U Blackboard eraser with dust collection feature |
| 05/13/1987 | CN86202504U Electrical dust-absorbing blackboard eraser |
| 04/01/1987 | CN86204919U Dust-suction blackboard eraser |
| 03/11/1987 | CN86104828A Movable black-board |
| 03/04/1987 | CN85106172A Magnetic chalk and chalk eraser |
| 01/21/1987 | CN86200138U Dustless black board eraser |
| 12/24/1986 | CN85105081A Rotary-type automatic erasing blackboard |
| 11/26/1986 | CN86200184U Dust-free blackboard eraser |
| 11/12/1986 | CN86202812U Efficient powder-sucking eraser for blackboard |
| 10/29/1986 | CN86200600U Dust-free blackboard eraser |
| 10/22/1986 | CN85205536U Dust-collecting blackboard eraser with outer jacket |
| 10/22/1986 | CN85203652U Automatic powder-sucking eraser for blackboard in which no power is necessary |
| 09/17/1986 | CN85102153A Automatic dust-absorbing blackboard brush |
| 09/03/1986 | CN85201761U No-dust blackboard eraser |
| 07/31/1986 | WO1986004302A1 Dust extractors |
| 07/16/1986 | CN85202691U Self-erasing ring shape blackboard |
| 07/09/1986 | CN85103322A Plane screw shaped dust-collecting brush |
| 06/24/1986 | US4596059 Automatic dust-removing eraser of a rolling-friction type for blackboard |
| 06/10/1986 | CN85102015A Auto-erasing motor-driven blackboard |
| 05/28/1986 | CN85201836U Automatically absorbing dust eraser |
| 05/07/1986 | CN85203567U Electric dust catching eraser |
| 04/02/1986 | CN85202270U Blackboard brush with electrical vacuum cleaner |
| 02/19/1986 | CN85201057U Blackboard eraser able to absorb chalk powder |
| 02/05/1986 | CN85201107U Thin motor-driven blackboard cleaning device with means for absorbing the chalk dust |
| 10/29/1985 | US4549327 Cleaner and chalk dust receptacle for chalk board erasers |
| 10/01/1985 | US4543680 Blackboard eraser handle |
| 07/31/1984 | US4462134 Blackboard eraser |
| 07/25/1984 | EP0114093A2 An eraser for an electronic blackboard |
| 08/16/1983 | US4399170 Method for smoothing wallboard tape joints |