| Patents for B43L 21 - Blackboard or slate-cleaning devices (5,409) |
|---|
| 09/22/1993 | CN2142400Y Dust-removing blackboard eraser |
| 08/25/1993 | CN1075453A Automatic eraser for blackboard |
| 08/19/1993 | WO1993015919A1 Eraser for white- or blackboards |
| 08/18/1993 | CN1021806C Electrostatic blackboard dust collecting method and its equipment |
| 08/04/1993 | CN2139526Y Chalk brush with cleaning device |
| 07/21/1993 | CN2138578Y Blackboard eraser for reducing dust pollution |
| 07/07/1993 | CN2137606Y Dust-collecting eraser of blackboard |
| 06/23/1993 | CN2136752Y Blackboard eraser with dust catcher |
| 06/23/1993 | CN2136751Y Electric blackboard eraser with dust catcher |
| 06/16/1993 | CN2136151Y Chalk dust absorbing blackboard eraser |
| 06/09/1993 | CN2135478Y Dustless blackboard eraser |
| 06/09/1993 | CN1072888A Dust-absorption device for blackboard eraser |
| 06/08/1993 | US5216776 Automatic blackboard eraser apparatus |
| 06/02/1993 | CN2134930Y Water-washed air-dried eraser |
| 05/19/1993 | CN2133466Y Dust-catched blackboard |
| 05/19/1993 | CN2133465Y Dust-catched eraser |
| 05/12/1993 | CN2132634Y Dust cleaning eraser without need of additional energy |
| 05/12/1993 | CN2132633Y Automatic chalk dust eliminating and cleaning brush |
| 05/12/1993 | CN2132632Y Rolling no-dust eraser |
| 05/05/1993 | CN2131715Y Simple blackboard eraser with dust collector |
| 04/28/1993 | CN2130708Y Dust obsorbing blackboard |
| 04/28/1993 | CN2130707Y 黑板擦 Eraser |
| 04/28/1993 | CN2130706Y Dust stored blackboard eraser |
| 04/14/1993 | CN2129696Y High efficient dust-remove blackboard eraser box |
| 04/07/1993 | CN2129229Y 电动黑板擦 Electric eraser |
| 04/07/1993 | CN2129228Y Chalk-collecting blackboard eraser |
| 03/23/1993 | CA1314842C Cap for a writing instrument |
| 03/17/1993 | CN1069935A Full swing dust collecting railings eraser |
| 03/10/1993 | CN1069695A Magnetic blackboard and its attachments of magnetic pen and magnetic eraser |
| 03/03/1993 | CN2127670Y Wiper-changeable magnetic eraser |
| 12/09/1992 | CN2124148U Semiautomatic blackboard eraser |
| 11/25/1992 | CN2122750U Multi-funcitonal rotary dust-absorbing eraser |
| 11/25/1992 | CN2122749U Dust-proof blackboard eraser |
| 11/18/1992 | CN2122071U Energy-storing vacuum dusting brush |
| 11/18/1992 | CN2122070U 板擦 Eraser |
| 11/11/1992 | CN2121350U No-dust eraser |
| 11/04/1992 | CN2120698U Miniature dust collecting brush |
| 11/04/1992 | CN2120697U Anti-dust eraser |
| 10/21/1992 | CN2119338U Portable electric speed-varying blackboard eraser with means for absorbing chalk dust |
| 10/14/1992 | CN2118646U Eraser with abscrbing the chalk dust means |
| 10/14/1992 | CN2118645U Health-care black-board cleaning device |
| 10/14/1992 | CN2118644U Cleaning means for mini electrical cleaning device |
| 10/14/1992 | CN2118643U Eraser with sealed cover |
| 09/30/1992 | CN2117262U Water brush for blackboard |
| 09/09/1992 | CN2115237U Combined dust absoption brush |
| 09/09/1992 | CN2115236U Dust-proof eraser |
| 09/02/1992 | CN2114577U Static dust resoving blackboard eraser |
| 08/19/1992 | CN2113178U Centrifugal electric dustless eraser |
| 08/19/1992 | CN2113177U Dustless eraser |
| 08/19/1992 | CN2113176U Eraser with dust collector |
| 08/12/1992 | CN2112521U Electric dust suction blackboard eraser |
| 08/05/1992 | CN2111862U Rotary blackboard cleaner |
| 08/05/1992 | CN2111861U Rolling and dusting eraser |
| 08/05/1992 | CN1063254A Dust-free blackboard, chalk and eraser installation |
| 07/08/1992 | CN2109320U Chalk powder suction blackboard eraser |
| 07/08/1992 | CN2109319U Rotary dust-suction blackboard eraser |
| 07/08/1992 | CN2109318U Dust-suction blackboard eraser |
| 07/08/1992 | CN2109317U Electric dust-suction blackboard eraser |
| 07/08/1992 | CN2109316U Detachable blackboard eraser |
| 07/08/1992 | CN2109313U Teaching aid series of board, eraser and pen |
| 07/01/1992 | CN2108635U Electric eraser with means for obsorbing chalk dust |
| 07/01/1992 | CN2108634U Eraser with automatic absorbing chalk dust |
| 07/01/1992 | CN2108633U Eraser with collecting dust function |
| 07/01/1992 | CN1062321A Floating dust-sucking eraser with double rollers |
| 06/10/1992 | CN2106733U Dust-absorbing blackboard eraser |
| 06/10/1992 | CN2106732U Electric dust-absorbing blackboard eraser |
| 06/03/1992 | CN2106087U Casing type eraser with dust catcher |
| 06/03/1992 | CN2106086U Rolling eraser with dust collector |
| 06/02/1992 | US5118272 Equipment for eraser manufacture |
| 05/27/1992 | CN2105412U Magnetic blackboard eraser |
| 05/13/1992 | CN2104140U Dust-catching eraser |
| 05/13/1992 | CN2104139U No-dust eraser |
| 05/06/1992 | CN2103461U Dust absorption blackboard eraser |
| 05/06/1992 | CN2103460U Dust-collected blackboard eraser |
| 04/29/1992 | CN2102855U Powder cleaning box for eraser |
| 04/22/1992 | CN2102204U Cleaner for blackboard eraser |
| 04/22/1992 | CN2102203U Powder suction blackboard eraser |
| 04/15/1992 | CN2101594U Electric chalk absorbing blackboard eraser |
| 04/08/1992 | CN2100991U Self-clean dust removeable blackboart eraser |
| 03/31/1992 | US5099541 Blackboard eraser apparatus |
| 03/25/1992 | CN2099684U Automatic box type eraser with dust collector |
| 03/11/1992 | CN2098394U Eraser with electric dust collecting |
| 03/10/1992 | US5094789 Method for eraser manufacture |
| 03/04/1992 | CN2097761U Hygiene eraser |
| 02/26/1992 | CN2097107U Dust removal blackboard eraser |
| 02/26/1992 | CN2097106U Dust-preventing blackboard eraser |
| 02/26/1992 | CN2097105U Dust-collecting type blackboard eraser |
| 02/19/1992 | CN2096480U Economical blackboard eraser |
| 02/19/1992 | CN2096479U Blackboard eraser |
| 02/19/1992 | CN2096478U Blackboard eraser without dust |
| 02/19/1992 | CN1058751A Electric eraser |
| 02/12/1992 | CN2095783U Blackoard eraser |
| 02/12/1992 | CN2095782U 吸尘黑板擦 Eraser dust |
| 01/22/1992 | CN2093765U Dust-proof blackboard eraser |
| 01/22/1992 | CN2093764U Dust-collecting blackboard eraser |
| 01/22/1992 | CN2093763U Blackboard eraser with a teaching-rod |
| 01/22/1992 | CN2093762U Electric device for cleaning the blackboard |
| 01/15/1992 | CN2093102U Charging type eraser with dust collector |
| 01/08/1992 | CN2092446U Dust-absorbing blackboard eraser |
| 12/25/1991 | CN1057231A Electrostatic blackboard dust collecting method and its equipment |