US1545961A - Blackboard eraser - Google Patents

Description

July 14, 1925. 1,545,961

M. R. KEENAN BLACKBOARD ERASER Filed Oct. 10, 1924 A A TTUR/VE Patented July 14, 1925.

UNITED STATES PATENT OFFICE.

MADELINE B. KEENAN, OF BROOKLYN, NEW YORK.

BLACKBOARD ERASER.

Application filed October 10, 1924. Serial No. 742,781.

To all whom it may concern:

Be it known that I, MADELINE R. KEENAN, a citizen of the United States, residing at 6 1-5 10th Street, Brooklyn, in the county of Kings and State of New York, have invented new and useful Improvements in' Blackboard Erasers, of which the following is a specification.

The invention relates to ,erasers of the kind used in erasing chalk from blackboards.

In school rooms where blackboards and chalk are used extensively it is well known that quantities of chalk dust are thrown into the air by the use of the ordinary blackboard erasers, and that this is detrimental to health, injurious to clothing and generally annoying and inconvenient. The draw back is, in fact, a serious one.

The object of the invention is to provide an eraser that will do away with these conditions. Means are provided for moistening the felt pad on the eraser with a suitable liquid which will dissolve the chalk on the board and thus eliminate any possibility of chalk dust flying about. A particular object is so to design the eraser that the pad may be quickly and evenly charged with a desired amount of the liquid.

Further objects and features of the improved eraser will be brought out in the following specification and illustrated in the drawings forming a part thereof.

Referring to the drawings:

Fig. 1 is a longitudinal sectional view,

Fig. 2 is a cross sectional view, taken on the line 22 of Fig. 1, and

Fig. 3 is a detail perspective view of the member forming the partition between the two compartments of the liquid receptacle.

The reference numeral 4 designates the body casing, made tight so as to serve as a liquid receptacle and provided with a handle 5 and a plug 6 that may be removed for filling. The receptacle is preferably made in the form of an oblong box, open at its front or under side, and having a flange 7 around the edges of this open side of which is secured by stitching 8, or other means, the eraser pad 9.

A plate 10 forming a partition is secured in the lower part of the casing. This plate may be flanged as shown so that it may be conveniently secured in the casing by soldering, or otherwise. As shown in Figs. 1

and 2 this partition serves to divide the casing into two compartments, a large compartment or reservoir 11 and a small one 12 constituting a charging and distributing chamber substantially coextensive with the area of the pad. The large compartment acts as a storage compartment and holds sufficient liquid to supply the eraser pad for some time. The small compartment holds enough liquid to moisten the pad .for innnediate use.

Means are provided for allowing the fluid to pass from the large compartment to the small one and in the present embodiment of the invention comprise a valve member 13 which is normally held seated on the valve seat 14, formed in the partition 10, by a spring 15. When the valve 13 is unseated the liquid will be free to flow into the smaller compartment.

Means are provided in the small compartment to insure the liquid being distributed or spread over the eraser pad so that all parts of it will be moistened. This means comprises a perforated plate 16 which is mounted between the eraser pad and the partition. When the valve 13 is opened the fluid will enter the small compartment and pass through the fine perforations in the plate 16 and thence to the eraser pad. After using the eraser a few times one will easily be able to determine how long the valve 13 should be held open to moisten the felt pad sufficiently.

Means are provided for operating the valve 13 and at the same time allowing air to enter the large compartment while the liquid is flowing into the small compartment. The valve 13 has a valve stem 17 in the reservoir and this valve stem has on its upper end a push buttom 18 for forcing the valve 13 to open. This member 18 in reality constitutes another valve. As the memher 18 is pushed down to unseat the valve 20 is confined between the member 18 and a shoulder or collar 21 on the valve stem. This spring 20 might be eliminated if it were desired to make the partition wall 10 flexible enough so that the heavy spring 15 would insure both valves being seated;

Bars 22 supported at their ends in the flange of the plate 10 extend across the subchamber of the compartment 12; which is below the perforated plate 16. These bars form a grid intervening directly between the perforated plate and-the'back oi the pad, the function of which is to preserve this sub-chamber by holding the pad away from theplate, as clearly seen in Fig. 1.

A preferred embodiment of the invention has been described and illustrated andit is to be understood that numerous changes may be made in the details of construction without departing from the spirit of the invent-ion as embodied in the claim.

What I desire to claim as new is:

A blackboard eraser comprising an oblong a bozqa' pad secured totlielow'er edge's thereof, a partition wall extending across the lower part of the box adjacent said pad 'to' form a large" reservoir compartment charging compartinent betWeen the valvedp'a-rt-ition and the pad, and means spacing;- the pad from said perforated plate, said means comprising bars forming a grid intervening, between said perforated plate and the back of the pad and preserving a subohamber of the distributing compartment between'saidplate-and pad; H MADELINE R. KEENALN.

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