US 3509644 A
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May 5, 1970 M P. SANTELL ET AL SELF-CLEANING BLACKBOARD Filed June 28, 1968 'NVENTOBE:
M/a/ma 1. 5.4117644 E/cH/azoE.Pan draws F. 6420 9 QMAMPQLQM Bv ATTORNEY United States Patent SELF-CLEANIN G BLACKBOARD Michael P. Santell, 5545 S. 106th St., Hales Corners, Wis. 53130; Richard E. Powers, 6098 N. Hopkins St., Milwaukee, Wis. 53209; and Steven F. Claus, 1509 Manitowoc St., South Milwaukee, Wis. 53172 Filed June 28, 1968, Ser. No. 741,037
Int. Cl. B43] 1/00; G091? 7/04 US. Cl. 35-66 2 Claims ABSTRACT OF THE DISCLOSURE An immobile blackboard writing surface and a magnetic sheet on a top hinged panel behind it, whereby a ferrous material can be applied in writing on said writing surface and will remain thereon until the magnetic sheet is pulled out of magnetic range, whereupon the ferrous writing material will fall into a receptacle from which it may be reclaimed.
BRIEF SUMMARY OF THE INVENTION A fixed vertical writing surface of a plastic material has a backing of any suitable material, and behind said backing is a sheet of magnetic material such as Koroseal adhesively fixed to a top hinged sheet of rigid material. Ferrous material is applied to the writing surface by a writing implement and is retained in written form by the adjacent magnetic attraction, and when erasure is desired a lever or cord is used to move the magnetic sheet away from the writing surface. Removal of the magnetic attraction thus drops the ferrous material into a trough under the writing surface for reclamation and subsequent use.
FIG. 1 is a vertical cross-sectional view taken from the side of a board assembly embodying the invention.
FIG. 2 is a view in perspective of a self-erasing board assembly.
FIG. 3 is an enlarged fragmentary vertical cross-sectional view of the board elements in writing position.
FIG. 4 is a similar view of the rear panel in retracted position.
DETAILED DESORIPTION In FIG. 1, a back panel is shown, 10, attached to wall 11, with a bottom 12 and top 13 fronted by the frame element 14 and a plastic writing surface 15 adhesively or otherwise attached to the fixed panel 16. A rear panel 3,509,644 Patented May 5, 1970 17 is hinged at 18 of the top element 13 and is frontally covered by the magnetic sheet of Koroseal 19. The writing implement 20 applies ferrous material or shredded magnetic tape 21 to the writing surface where it is retained in form by the magnetic force of the Koroseal 19. To erase, a handle 22 attached to cord 23, in turn engaged about the pulley 24 and tethered at 25 to the lower portion at the rear of panel 17 may be pulled to remove the magnetic force by withdrawing the Koroseal from proximity to the Writing surface 15, allowing the material 21 to drop into a trough 26 from which it may be reclaimed for subsequent use.
It will be understood that the device is capable of many modifications in structure and design, without departing from the spirit of the invention, within the scope of the appended claims.
Having thus described the invention, what is claimed and desired to be secured by Letters Patent of the United States is:
1. A self-erasing blackboard including a fixed writing surface, a panel coextensive in area with said surface disposed behind said writing surface and hinged at its top to lie in close proximity with and to be displaced away from said writing surface, a magnetic sheet on the frontal surface of said hinged panel, means for writing with ferrous material on the writing surface, and means for withdrawing the hinged panel and magnetic sheet from proximity to said writing surface to free the ferrous material for subsequent use.
2. A device as in claim 1, including a backing fixed rearwardly of said writing surface sheet, and said means for withdrawing the hinged panel and attached magnetic sheet is a cord puller.
References Cited UNITED STATES PATENTS 1,881,140 10/1932 Settel 66 2,746,172 5/1956 Crow -1 35-19 3,093,919 6/1963 Holtz 142 EUGENE R. CAPOZIO, Primary Examiner H. S. SKOGQUIST, Assistant Examiner