of the knob should preferably have a large pitch and/or a large teeth height.
When the eraser mounting member carrying the eraser is slid by the knob, both of the pinions provided to the eraser mounting member will rotate in accor- 5 dance with their engagement with their respective racks provided to the case and the eraser will erase the display on the magnetic display panel.
In the case of the wall-mounted display panel, the eraser mounting member has its own weight supported 10 by the roller guide so that there is a little moving friction, and it is possible for it to move smoothly.
The nature, utility, and further features of this invention will be more clearly apparent from the following detailed description with respect to preferred embodi- 15 ments of the invention when read in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a vertical section of a first embodiment of a 20 magnetic panel display device to which the present invention has been applied;
FIG. 2 is a section taken along the line II—II in FIG.
FIG. 3 is a front view of the display device according 25 to the first embodiment;
FIG. 4 is a partially sectional elevation of a shaft with pinions used in the first embodiment;
FIG. 5 is an elevation of an eraser mounting member used in the first embodiment; 30
FIG. 6 is a vertical section of a second embodiment of the present invention;
FIG. 7 is a section taken along the line XII—XII of FIG. 6;
FIG. 8 is a front view of a display device according to 35 the second embodiment;
FIG. 9 is an elevation of an eraser mounting member used in the second embodiment;
FIG. 10 is a view similar to FIG. 1, showing a third embodiment of the present invention; 40
FIG. 11 is a sectional view taken long the line XI—XI in FIG. 10; and
FIG. 12 is a view, on an enlarged scale, showing pinions and racks used in the third embodiment.
DESCRIPTION OF THE PREFERRED 45
The following is a description of embodiments of the present invention, with reference to the appended drawings. In the figures, corresponding parts and ele- 50 ments are indicated with the same reference numerals.
The description will commence from a description of the embodiment shown in FIG. 1 through FIG. 5. As shown in FIG. 1 and FIG. 3, a display device 1 has a case 2 in the shape of a rectangular box, which has a 55 front display window 17. Inside this case 2 are provided a magnetic display panel 4 that is mounted on the front side (left side as viewed in FIG. 1) of a support plate 3 of a non-magnetic material. To an upper portion 5' of a rear frame 5 fitted in the rear of the case 2, opposite the 60 upper edge of the magnetic panel 4, is fixedly provided a horizontally extending first rack 6 that is slightly longer than the upper edge of the magnetic panel 4 as shown in FIG. 2. To a lower portion 5" of the frame 5, opposite a lower edge of the magnetic panel 4, is pro- 65 vided a horizontally extending second rack 7 which is slightly longer than the lower edge of the magnetic panel 4, and which has the same pitch of the teeth as
that of the first rack 6. The first and second racks 6 and 7 are parallel to each other and are arranged so that the tooth peaks and valleys of these racks 6 and 7 are at vertically corresponding positions. The racks 6 and 7 may be formed integrally with the rear frame 5.
As shown in FIG. 4, upper and lower ends of a vertical shaft 8 have respectively first and second pinions 9 and 10 fixed thereto. The teeth of the pinions 9 and 10 respectively engage with the teeth of the racks 6 and 7. The pinions 9 and 10 have the same pitch and pitch circle. Pins 11 and 12 that pass through the shaft 8 are respectively fitted in a slot 13 of the first pinion 9 and a slot 14 of the second pinion 10.
Within the case 2 is provided a vertically elongated eraser mounting member 15. As shown in FIG. 5, in a rear surface of the eraser mounting member 15 are provided upper and lower recesses 16a and 16b and a groove 16c connecting these recesses. These recesses 16a and 166 respectively house the pinion 9 and the pinion 10 of the shaft 8 in a manner that they are rotatable within the recesses. The groove 16c receives the shaft 8 rotatably therein. The rear surface of the mounting member 15 has upstanding parallel ribs 40. The recesses 16a and 16b also have parallel ribs 41 and 42, respectively. The ribs 41 and 42 determine relative vertical position between the pinions 9,10 and the mounting member 15. To the front surface of the eraser mounting member 15 is mounted an eraser magnet 20 which is located in the central portion in the direction of the vertical dimension of the member 15. The eraser magnet 20 is fitted via a resilient member 19 in a vertical groove 18 formed slightly longer than the vertical dimension of the display window 17 of the display device 1.
The eraser mounting member 15 is so supported in the case 2 with the ribs 40 thereof disposed between horizontally extending protrusions 21 (FIG. 1) of the rear frame 5 that the eraser magnet 20 will slidingly contact the rear surface of the support plate 3 and that the pinions 9 and 10 will mesh with the racks 6 and 7, respectively. The weight of the eraser mounting member 15 is borne by the lower protrusion 21 via the ribs 40. The eraser magnet 20 exerts a magnetic force to the magnetic panel 4 from the rear side of the panel 4 and via the support plate 3.
To a lower end portion of the front surface of the eraser mounting member 15 is fixed a knob 23 which protrudes forwards at a position higher than the lower pinion 10. The knob 23 protrudes to the outside through a slot 22 provided to the case 2, the slot 22 extending parallel to the racks 6 and 7. Erasing the display on the magnetic panel 4 is performed by horizontally sliding the knob 23 so as to move the eraser mounting member 15 horizontally along the racks 6 and 7.
FIGS. 6 through 9 show a second embodiment of the eraser assembly of a display device of wall-mounted type. Inside the case 2' of the display device 1' is mounted a magnetic panel 4 in the same manner as described above for the first embodiment. In addition, in the same manner as in the first embodiment, portions 55' and 55" of a rear frame 55 provided to the rear of the case 2' are respectively provided with an upper first rack 6 and a lower second rack 7 that are integral with the portions 55' and 55".
Also in the same manner as in the first embodiment and as shown in FIG. 9, the rear surface of an eraser mounting member 15' is provided with recesses 16a' and 16b' formed adjacent to the upper and lower ends of the