US2874398A - Blackboard-eraser cleaner - Google Patents

Description

J. M. D] FERSIO BLACKBOARD-ERASEZR CLEANER Feb. 24, 1959 2 Sheets-Sheet 1 Filed May 28 1956 INVENTOR; Jose oh M. pipe/".51

United States Patent BLACKBOARD-ERASER CLEANER Joseph M. Di Persio, New York, N. Y.

Application May 28', 1956, Serial No. 587,719

4 Claims. (Cl. 15-94) V The invention relates to a cleaning device for blackboard-erasers, and relates more particularly to such a device for shaking chalk dust ofi the eraser felt.

The invention has among its objects to provide for a device that includes a vibratable screen and a limit stop or stops, with the eraser held in abutment against the upper screen surface and moving with the screen, .to shake out the dust therefrom by impact when the movement of the screen in at least one direction is suddenly brought to a stop;

The foregoing and other objects of the invention will be best understood from the following description of exemplifications thereof, reference being had to the accompanying drawings, wherein:

Fig. 1 is an extended perspective view of a blackboarderaser cleaner, in accordance with an embodiment of the invention;

Fig. 2 is a plan view of the assembled cleaner shown in Fig. 1;

Fig. 3 is a transverse sectional view of the embodiment of the preceding views, taken on line 3--3 of Fig. 2;

Fig. 4 is a perspective view of a modified cleaner; and

Fig. 5 is a longitudinal sectional view of the modified cleaner of Fig. 4, taken on line 55 of Fig. 4. g

In carrying the invention into effect in the embodiments which have been selected for illustration in the accompanying drawings and for description in this specification and referring now particularly to Figs. 1, 2, and 3, there is provided a casing generally indicated at 11, which has a bottom 12 and side walls 13. The casing 11 may be made of any suitable structural material such as wood, metal, or plastic. The casing 11 defines on the interior a chamber 16, and is open at the top 14. In the chamber 16 there is disposed a vibratable member 17, that comprises a screen 18 and easing engaging members such as legs 19. The screen 18 is elongated and rectangular, and has an outline slightly larger than a conventional blackboard-eraser 21.

Two helical compressing springs 22 are disposed in the chamber 16, and support from below the end portions of the screen 18. The springs 22 are so dimensioned that they normally maintain the lower edges 23 of the legs 19 spaced above the bottom for a distance a (Fig. 3).

During operation, the felt portion 24 of the eraser 21 is pressed with its face downwardly abutting against the top surface of the screen 18. The casing 11 is so dimensioned that in this position the entire assembly of the screen 18 and the springs 22 and the blackboard-eraser 21 aggregates to a height which is inferior to the height of the side walls 13, so that the topmost surface of the eraser 21 is disposed below the open top 14. The operator will tap the eraser with his finger, thereby causing reciprocable vertical movement of the screen 18 with the eraser 21. The pressure exerted by the tapping finger will move the screen 18 downwardly until the lower edges 23 of the legs 19 strike the bottom 12 of the casing 13. Upon that impact, dust will be shaken off the felt 24, and will fall through the openings of the screen 18 and will collect in a lower dust collecting zone 26 of the chamber 16. The springs 22 will return the screen 18 and the eraser 21 to resume the initial position (Fig. 3), in which the operator will again tap the eraser. This may be continued until most or all of the dust is shaken out of the felt 24.

The screen 18 and the springs 22 may easily be removed from the chamber 16, for cleaning of the chamber 16 and for removal of the dust from the zone 26 thereof.

Instead of tapping with a finger, the operator may employ any conventional suitable impact actuator such as a hammer or mallet or the like.

In the modification illustrated in Figs. 4 and 5, there is a casing 31 which includes a bottom32, side walls 33, anda lid 34. Screen supports, for instance two or four tubular screen supports 36 are mounted on the bottom 32, one near each corner of the casing 31. Each tubular support 36 is hollow on its interior 37 and is closed vibration screen 44. The enlargement 43 of each pin 42 is larger than the aperture 41 of the cover 38 so that, when the pin 42 is pressed upwardly, the enlargement 43 will abut from below against portions of the cover 38 thereby providing a limit for the upward movement of the screen.

A helical compression spring 46 surrounds each pin 42, urging the screen 44 and the pins 42 into the upper position (shown in solid lines in Fig. 5) When the screen 44 is pressed downwardly, the downward movement will be stopped by the abutment between the screen 44 and the bosses 39 (shown in broken lines in Fig. 5). In each tubular support 36 there is disposed an impact element such as a sphere 47 which, upon shaking of the casing 31, will move to and from impact with the enlargement 43.

The casing 31 defines on its interior a chamber 48 which has near the bottom 32 a lower dust collecting zone 49. A protective screen 51 is mounted fixedly in the casing 31 above the zone 49. The protective screen 51 preferably is a fine mesh screen which will have the tendency to retain dust in the zone 49 which has collected there. The dust will pack in underneath the surface of the screen 51. The vibrating screen 44, on the other hand, is disposed, and moves, in a region of the chamber 48 which is spaced from the dust collecting zone 49. A closure 52 is provided in the side wall 33 adjacent the zone 49, to facilitate emptying the zone 49 of dust.

The height of the walls 31 is so dimensioned that a standard blackboard-eraser 21 when placed with its felt 24 against the screen 44, while the latter is in the upper position, willin its entirety be confined within the chamber 48, and be clear ofi the lid 34.

The lid 34 has on its underside a flange structure 53 i that is substantially proportional to, though larger than, the outline of the eraser 21. The lid 34 is hinged at 54 to the casing 31 and is tiltable about the hinge axis for opening and closing. Conventional locking means 56 are provided for temporary latching of the lid 34 to the side wall 31. When the lid 34 is closed, the flange 53 will extend downwardly beyond the normal upper position of the screen 44.

To operate the modified cleaner of Figs. 4 and 5, the operator will open the lid 34 and place the eraser 21 on the screen 44. Then he will close the lid 34, and grasp the casing 31 as shown in Fig. 4, to shake it. At the end'of the downward movement of the casing 31, the weight of the screen 44, the eraser 21 and of the pins 42 with the enlargements 43 will press the screen 44 downwardly against the power of the springs 46, while Patented Feb. 24, 1959' at the end of the upward movement the spheres 47 will strike the enlargements 43 thereby aiding the springs 46 to return the screen 44 to the upper position,

During the downward movement of the screen44, it will strike the bosses 39 and the impact will shake chalk dust out of the felt 24. The dust will fall through the meshes of the screens 44 and 51 and will collect in the zone 49.

During the upward movement of the screen, it will be stopped by the impact between the enlargements 43 and their covers 38, but the eraser 21'will continue the upward movement until it strikes the lid 34. Upon the impact, some dust will be shaken out of the felt 24.

When the operation has been completed and the eraser 21 removed, the operator may grasp the handle 57 to open the closure 52, to empty the dust out of the zone 49.

I wish to be understood that I do not desire to he limited to the exact details of construction shown and described, for obvious modifications will occur to a person skilled in the art.

Having thus described the invention, what I claim as new and desire to be secured by Letters Patent, is as follows: I

1. In a blackboard-eraser cleaner, in combination, a casing defining a chamber having a'fiat bottom surface, a horizontal screen reciprocable vertically in opposite directions relative to said casing within a region of said chamber spaced above said bottom surface and having a portion adapted to receive in abutment the face of a blackboard-eraser, resilient means urging said screen upwardly and means connected to said screen and comprising two legs operable to strike said surface when the screen is pushed downwardly against the force of said resilient means operable to limit the downward movement of said screen, each leg having a straight lower edge adapted to engage said bottom surface during striking impact.

2. In a blackboard-eraser cleaner, as claimed in claim 1, said screen'being elongated, said'resilient means comprising two helical springs applying resilient force to said screen at the opposite end portions of said screen, said springs being supported by said casing.

3. In a blackboard-eraser cleaner, as claimed in claim 1, said resilient means being operable to keep said screen in all positions substantially parallel to said bottom surface.

4. In a blackboard-eraser cleaner, in combination, a casing defining a chamber open on top and having a flat bottom surface, a horizontal screen disposed in said chamber above said surface, resilient means urging said screen upwardly away from said surface to an upper position within said chamber, said screen being manually movable vertically downwardly against the force of said resilient means, said screen including vertical legs having flat lower edges adapted to engage said fiat surface in striking impact during the manually energized downward movement of said screen, said screen having a portion adapted to receive in abutment the face of a blackboarderaser for vibrating the same during said impact, for cleaning.

References Cited in the file of this patent UNITED STATES PATENTS 844,154 Long Feb. 12, 1907 886,075 Remington Apr. 28, 1908 1,375,642 Russell Apr. 19, 1921 1,803,339 McConnell May 5, 1931 FOREIGN PATENTS 202,347 Germany Oct. 2, 1908 589,419 Great Britain June 19, 1947

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