Apparatus for performing raised dot formations
The invention relates to an apparatus for performing raised dot formations, said apparatus comprising a running belt forming an endless loop and having a great number of holes adapted to receive balls therein. Particularly said dot formations are meant to represent symbols of the Braille-code type readable to people with visual defects. 
     Books suitable for reading by blind people generally consist of pages of stiff paper material wherein the Braille symbols are formed by raised dots or embossments grouped in matrices of 2×3. The absence of one or more of the six dots in the matrix makes the symbols distinguishable and each representative of the corresponding alpha-numerical character. Such books are hard to manufacture and expensive, and are also bulky and difficult to handle. 
     The object of the invention is to replace such permanent registration of literature or the like by a running and temporary exposition of successive small parts of the matter in question and to make said exposition readable to people with visual defects. 
     In an apparatus of the above-mentioned kind the object of the invention is reached in principle by filling a great number of holes in the running endless belt with balls, sorting-out certain balls in a group of holes at a sorting station so as to form a Braille symbol of dots represented by balls extending above the upper face of the belt, reading-off the symbol by tactile perception at an exposition area and then erasing the symbol by filling all holes anew with balls for the next turn of the belt. The essential characterizing features of the apparatus according to the invention are set forth in the following claims. 
    
    
     The invention will now be more closely described with reference to the accompanying drawings, in which 
     FIGS. 1-3 refer to a first embodiment of the apparatus according to the invention. 
     FIG. 1 shows the same as viewed from a vertical longitudinal plane, 
     FIG. 2 is a view taken from above, and 
     FIG. 3 is an enlarged perspective view of a fragment of the apparatus taken at an inclined angle from above. 
     FIG. 4 shows a first modification of the details of FIG. 3. 
     FIG. 5 shows a second modification thereof in vertical section. 
    
    
     In the drawings, an endless belt 11 is laid in a loop around two parallel rollers 13, 15 rotary about generally horizontal axes 14, 16, one of them driven by a motor 17 (or other powering means). The belt is moved in the direction of the arrow without slippage, perforation holes 19 at the edge of the belt engaging pegs 21 on the roller 15. The belt comprises an upper substantially horizontal or slightly inclined path 18, a semicircular path 20 around the roller 15, a lower substantially horizontal or preferably slightly upwardly inclined path 22 and a semicircular path 24 around the roller 13. Between the rollers 13, 15 the upper belt path 18 rests upon and is drawn in contact with an underlying support 23 in the shape of a table. Closely situated parallel grooves 27, 28 in the upper face of said table extend in the direction of travel of the belt 11. 
     The belt is perforated by a great number of small through holes 29 adapted to receive spherical balls 31 and of a slightly greater diameter than that of the balls. The holes are arranged in longitudinal and transverse rows and are dimensioned and spaced so as to form square groups corresponding to the Braille matrix system. The balls are made of steel, but some suitable plastic or ceramic material may be used instead. A preferred diameter of the balls is of the order of 1.6 mm, and the thickness of the belt 11 is of the order of 0.2 mm. 
     The belt holes are filled with balls at an area A of the lower path 22 of the belt loop, and after turning around the roller 13 the belt arrives at a second area B located close to the starting end of the upper run 18 of the belt. 
     At said area there are provided means for selectively removing some of the balls from positions within the belt holes. Said means form a sorting station, in which selected balls are allowed to drop out by the action of gravity. From there the belt passes towards and past an exposition area C, where the pattern of Braille symbols formed by the remaining balls of a group can be read off by a blind person using his finger tips. 
     The sorting station B is in principle arranged as a series of traps extending in a row transversely of the belt and each positioned below a longitudinal row of belt holes. Forming part of the sorting station is a slot 25 in the support 23, extending transversely thereof and having a dimension in the direction of travel of the belt somewhat greater than the diameter of the balls, so that balls can escape therethrough into the open space inside the belt loop. 
     To the sorting station B there also belongs a series of obstacles placed in said slot 25 and selectively displaceable so as to either block the passage of balls through the slot or allow the dropping of balls by gravity into the interior of the belt loop. In the shown embodiment said obstacles are formed by vertical bars 33 which extend upwardly into the slot 25, their upper flat end faces 35 being flush with the bottoms of the grooves 27, 28. Said bars 33 can be shifted sideways, i.e. in the direction of the slot 25, between an active position (shown at the right of FIG. 3) and an inactive position (shown at the left of FIG. 3). In the active position any bar end 35 forms a &#34;bridge&#34; which supports the balls of a corresponding longitudinal row of balls during their passage of the slot 25. In the active position the bars allow balls to pass through the slot and the thus downwardly opened escape way, as indicated by the line 37 and three intersecting circles in FIG. 3. 
     In one embodiment shown in FIGS. 1 to 3 said bars 33 consist of ceramic material which due to the piezoelectric effect will bend under the influences of electric control impulses, their upper ends 35 moving in the slot 25, as explained, while their lower ends are rigidly attached. A control device 39 supplying said electric impulses to the bars is controlled by a computer 40 connected to a manually operable keyboard 42 or some other input means, such as a punched tape, a disk record or a data memory, supplying the text to be presented at C either in alpha-numeral form or in digital form. The computer transforms the characters of this information into Braille-code and serves it to the control device 39. The computer 40 also controls the motor 17 in order to synchronize the movement of the belt (either continuous or stepwise) with the operation of the bars. The speed of the belt can also be controlled manually. 
     The balls sorted-out drop down into a closed spaced bordered by the belt loop and two opposed end walls 41 of an enclosing cover. Beneath the sorting station B there is inserted a ball catching ramp 43 which diverts the rolling balls towards the roller 15. They are collected close to said roller to form a store 45 of balls resting upon the lower run 22 of the belt. 
     Said store supplies balls for refilling all empty holes of the belt. A possible excess of balls will be pushed back by a scraping means 47 before the belt turns around the roller 13 and starts a new turn. 
     The apparatus thus far described may be completed by printing means for transmitting the Braille-readable tactile perceptible ball configuration into permanent impressions in a web of sheet material. Said printing means comprises a roller 55 having an external surface of yieldable material, about which a web 59 of sheet material is looped. The axis 54 of said roller is journalled in eccentric bearings 56 which are turnable by means of a handle 57. By manipulating the same the roller can and will be shifted from an off-lying inoperative position into the shown active position, in which it presses the web against the balls extending through holes of the running belt. 
     In the modification of FIG. 4 the support table 23 has a completely flat upper face, i.e. it has no grooves as in FIG. 3. Here the belt consists of rubber and has a thickness of the order of 0.7 mm, i.e. it is approximately as thick as half the diameter of the balls, in order securely to retain them in the holes and to expose a part of the ball tops conveniently large for the tactile sensing of the Braille symbols. 
     FIG. 5 shows a further modification consisting in that the ball selection takes place by the use of magnetic forces. Above each longitudinal row of belt holes and opposite to the slot 25 of the support table 23 there is placed an electromagnet 61 in such a position that the balls 31 roll or slide along its pole shoe 63. When electric current is supplied to the electromagnet, the same keeps the ball attracted during its passage of the slot 25, thus preventing it from dropping therethrough. On the other hand, when the electromagnet is shut off, the gravity force prevails, and therefore the ball will drop freely through the slot 25. 
     At the exposition area C the ball patterns are presented as on a book page, several parallel rows of consecutive characters being shown simultaneously and readable in the transverse direction of the belt. According to a modification, the Braille characters may be read lengthwise of the belt, and in that a case a simplified version of the apparatus may comprise a belt having merely three longitudinal rows of holes. 
     From the above it is evident that an apparatus is created, by the use of which people with visual defects are given the possibility of taking part, at a desired moment, of literature recorded in other forms than by Braille code, and that other messages can be transmitted to them without significant delay otherwise than orally. 
     Of course, the above-described apparatus may be modified in several respects within the framework of the following claims.