GB2083414A - Blackboard wiper assembly - Google Patents

Abstract

A blackboard wiper assembly includes a wiper (4) and a dust collector (2) which are disposed in spaced relationship. The wiper (4) is provided with a suction hole while the dust collector houses a suction motor (8). The suction hole in the wiper communicates with the dust collector (2) through a suction tube (3) which permits a movement of the wiper (4) in any desired direction. The suction motor (8) can be operated by an external switch. <IMAGE>

Description

SPECIFICATION Blackboard wiper assembly BACKGROUND OF THE INVENTION When erasing letters and characters or other figures written on a blackboard in chalk by utilizing a blackboard wiper, it is possible that the dust or powder of the chalk may be dispersed into the surrounding and suspended in the air, which may be aspirated by a man to injure his health. In addition, the place around the blackboard becomes contaminated, presenting a disgraceful appearance. In addition, the dust of the chalk which attaches to the blackboard wiper must be removed by patting it or utilizing a cleaner.

To cope with this problem, there has been proposed a wiper assembly which internally houses a fan motor for withdrawing the dust of the chalk, produced when wiping the board, through a suction hole which is centrally formed in the assembly to collect the dust within a given cavity. However, this wiper assembly of the prior art is formed as a unit which is completely independent from the blackboard. Accordingly, a fan motor of an increased size which is capable of producing a suction of a greater magnitude cannot be internally housed within the unit, inasmuch as the size of the latter is limited in consideration of the operating ease. In addition, a dry cell is utilized as a power source, again standing in the way to the achievement of a suction of a sufficient magnitude.This resulted in an imperfect withdrawal of the dust of the chalk, leaving much to be improved from the standpoint of sanitary considerations. Finally, the removal of the dust of the chalk which has been collected in the unit is troublesome.

SUMMARY OF THE INVENTION It is an object of the invention to provide a blackboard wiper assembly which facilitates a post-treatment by causing the dust of the chalk which has been withdrawn to be dropped and collected automatically at a given location.

It is another object of the invention to provide a blackboard wiper assembly capable of producing a suction of sufficient magnitude so that the dust of chalk can be completely withdrawn.

It is a feature of the invention that the assembly is provided with a wiper and a dust collector which are disposed in spaced relationship. The wiper is provided with a suction hole while the dust collector houses a suction motor. A communication is established between the suction hole of the wiper and the dust collector through a suction tube which permits a movement of the wiper in any desired direction. The suction motor can be operated by an external switch.

As a result of such features of the invention, the dust of chalk which has been wiped off from the blackboard by the wiper is withdrawn through the suction hole in the wiper and then collected by the dust collector through the suction tube. Hence, the only post-treatment is disposal of the chalk dust which has been collected in the dust collector, thus providing a blackboard wiper assembly characterized by an easy post-treatment.

Since the dust collector is spaced from the wiper in accordance with the invention it is possible to utilize a suction motor of an increased capacity within the dust collector, assuring a perfect withdrawal of the chalk dust. In this manner, there is provided a blackboard wiper assembly which eliminates the prior disadvantage that the chalk dust may be dispersed into the surrounding atmosphere to injure the health of the man.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a front view of one embodiment of the invention.

Figure 2 is an enlarged longitudinal section of a dust collector used in the embodiment of Fig. 1.

Figure 3 is a longitudinal section of a blackboard used with the embodiment of Fig.

1.

Figure 4 is an enlarged front view of a wiper used in the embodiment of Fig. 1.

Figure 5 is a cross section taken along the line V-V shown in Fig. 4.

Figure 6 is a fragmentary enlarged cross section of the wiper.

Figure 7 is an enlarged cross section of another part of the wiper.

Figure 8 is a front view of another embodiment of the invention.

Figure 9 is a longitudinal section of part of the embodiment shown in Fig. 8.

DESCRIPTION OF EMBODIMENTS Referring to Fig. 1, there is shown a blackboard 1, and a dust collector 2 is attached to the left-hand side of the blackboard toward the bottom thereof. A flexible suction tube 3 extends from the dust collector 2 and has a wiper 4 mounted on the free end thereof. The flexibility of the suction tube 3 permits the entire surface of the blackboard 1 to be wiped off while carrying the wiper 4 with one hand.

Referring to Fig. 2, the dust collector 2 comprises a cylindrical body 5 and a dust container 6 which is threadably engaged with the lower end of the body 3 in a detachable manner. The top wall of the body 5 is formed with air exhaust openings 7 while a suction motor 8 carrying a fan 8a is mounted within the body 5. At a location below the suction motor 8, the inner wall surface of the body 5 has a tubular member 9 mounted thereto, and an open end of a bag-shaped filter 10 is fitted around the lower end of the tubular member 9. A motor 11 is mounted on the lower end of the tubular member 9 and includes an output shaft carrying strikers 1 2 which slap the inside of the filter 7 while rotating.At a print below the support for the tubular member 9, the outer surface of the body 5 is formed with a connector 1 3 which projects laterally for connection with one end of the suction tube 3.

As shown in Fig. 3, a channel member 14 which is U-shaped in cross section is secured to the lower end of the blackboard 1 for receiving the flexible suction tube 3 therein.

Referring to Figs. 4 and 5, the wiper 4 comprises a rectangular dish-shaped body 1 5, a wiper member 16 and a wiper holder 1 7.

The inner surface of the body 1 5 is formed with a suitable member of step-like projection 1 5a while the outer surface of the holder 1 7 is formed with protuberances 1 7a at locations corresponding to those of the projections 15a.

In this manner, the holder 1 7 can be received within the body 1 5 until the protuberances 1 7a bear against the step-like projections 1 5a of the body 1 5. The left-hand side of the body 15, as viewed in Fig. 4, is formed with projections 15b which are wedge-shaped in cross section and which are located at locations corresponding to the step-like projections formed on this side.The spacing between the projections 15b and their corresponding steplike projections 1 5a is slightly greater than the thickness of the protuberance 1 7a formed on the holder 1 7. The righthand side of the body 15, as viewed in Fig. 4, is provided with leaf springs 1 8 which are disposed at an angle at locations aligned with the step-like projections 1 5a formed thereon, thus allowing the protuberances 1 7a on the holder 1 7 to be held between the leaf springs 1 8 and the step-like projections 15a. Accordingly, the holder 1 7 can be retained by the wiper body 15, by inserting the protuberances 1 7a formed on one side of the holder 1 7 into the space between the projections 15a, 15b formed on the body 15, and forcing the other side of the holder 1 7 against the resilience of the leaf springs 18 until the protuberances 1 7a thereon are held between the leaf springs 18 and the projections 15a. The holder 1 7 can also be removed from the body 15 by pulling the holder 1 7b upward while depressing the leaf springs 1 8 against their own resilience.

Since the holder 1 7 is retained in position by having its plurality of protuberances 1 7a disposed in abutment against the step-like projections 1 5a on the body 1 5 in the manner mentioned above, there results a plurality of slit-like suction holes or openings 20 formed between the outer surface of the holder 1 7 and the inner peripheral surface of the body 1 5 which open to the exterior. In addition, the wiper 1 6 is also formed with a pair of lengthwise extending suction openings 21, and the holder 1 7 is again formed with openings 1 7b which are aligned with the openings 21.

These suction openings 20, 21 communicate with a space 22 which is formed in the inner bottom of the wiper 15. The space 22 communicates with the flexible suction tube 3 through a connector 1 sic which is formed on one side of the body 1 5. By utilizing the suction tube 3 which contains a pair of coils, these coils may be used as lead wires. This arrangement may be convenient when it is desired to provide a start switch for the dust collector 2 within the wiper assembly 4.

In operation, when the surface of the blackboard 1 is to be wiped off, the suction motor 8 is initially started as by operating a switch which is located within the wiper assembly 4 or a switch located within the dust collector 2.

When the start switch is located within the wiper assembly 4, it may comprise a proximity switch having no mechanical contacts. This conveniently starts the suction motor 8 automatically whenever the wiper assembly 4 is held by one hand. When the suction motor 8 is set in motion, the rotation of the fan 8a causes the air to be withdrawn through the individual suction openings 20, 21 and through the space 22 in the wiper assembly, the connector 15c, the suction tube 3, the filter 10 and the tubular member 9. When wiping off any writing in chalk on the blackboard 1 by means of the wiper assembly 4, the powder or dust of the chalk may tend to be deposited on the wiper member 1 6 or to be dispersed into the surrounding.However, because the air is being withdrawn through the suction openings 20, 21, such dust of chalk is also withdrawn through the suction openings 20, 21 before it is deposited on the wiper member 1 6 or dispersed into the atmosphere. It will be appeciated that a majority of chalk dust tends to be deposited around the edge of the wiper member 1 6 and dispersed into the atmosphere, but the suction openings 20 formed around the wiper 1 6 has a reduced thickness than the suction openings 21 formed in the bottom of the wiper member 16, thus producing a greater speed of airflow.

Hence the chalk dust is subject to a greater suction in these openings, effectively withdrawing the chalk dust from the region around the wiper member 1 6.

After being withdrawn together with the air, the chalk dust passes through the suction tube 3 to enter the dust collector 2 where they collide with the filter 10. Only the filtered air passes through the filter and through the tubular member 9 and the suction motor 8 to be discharged through the exhaust opening 7. When the blackboard wiping operation is completed in this manner and the wiper assembly 4 is released, the operation of the suction motor 8 is automatically interrupted.

Alternatively, the motor 8 may be manually stoped. This terminates a suction operation, allowing the chalk dust precipitated on the filter 10 to fall dowel1 by gravity to be col lected within the dust container 6. Since the filter 10 is subject to plugging, the motor 11 may be suitably started to pat the filter 10 by the strikers 1 2 as the latter rotate, thus forcedly separating the chalk dust from the filter 10. It will be a convenient use if the motor 11 is started and set in operation for a given time interval in synchronized relationship with the termination of operation of the suction motor 8. The chalk dust thus collected may be suitably disposed of by removing the container 6 from the dust collector 5.

It will be appreciated that the motor 11 may be replaced by a vibrator which oscillates the filter 10. In addition, the dust collector and the suction motor may be disposed at separate locations. However, it is necessary that the suction motor be located downstream of the dust collector with respect to-the airflow.

Figs. 8 and 9 show another embodiment of the invention. Referring to Fig. 8, a coiler 30 is attached to the bottom of the blackboard 1 for coiling the flexible suction tube 3. The dust collector 2 is attached to the lateral side of the coiler 30 and is connected thereto through a connection tube 31. The distal end of the flexible suction tube 3 which is disposed on the coiler 30 extends upwardly and is connected to the wiper assembly 4. The coiler 30 may be an arrangement similar to the one which is used to coil a rubber hose or a cord. The coiler 30 may be resilitently urged in a direction to take up the suction tube 3 thereon, or may be manually operated.When the coiler 30 is urged by a spring to take up the suction tube 3, an arrangement may be provided which locks the suction tube after any desired length thereof has been reeled off the coiler 30 and which causes the suction tube 3 to be reeled on when unlocked. The wiper assembly 4 is connected to the flexible suction tube 3 which is adapted to be taken up on the coiler 30. Accordingly, the entire surface or any desired portion of the blackboard 1 can be wiped off the wiper assembly 4 held by one hand, owing to the flexibility of the suction tube 3 and the reeling on and off of the suction tube from the coiler 30.

Referring to Fig. 9, the lower end of the blackboard 1 is formed with a ledge (1a which projects forwardly. The top plate 32 of a casing in which the coiler 30 is housed is secured to the lower end face of the ledge la.

The ledge 1 a and the top plate 32 of the coiler 30 are formed with elongate slots 1 b, 32a, respectively, through which the flexible suction tube 3 extends in a loose fit. The elongate slot 1 b has a width which is less than the thickness of the wiper assembly 4 so that the latter is engaged with the ledge 1 a of the blackboard 1 when the suction tube 3 is reeled onto the coiler 30.

The dust collector 2 may be constructed in the same manner as mentioned previously.

With the embodiment illustrated in Figs. 8 and 9, only a limited length of the suction tube is reeled off when the wiper is used while the suction tube is reeled on the coiler when the wiper assembly is not in use, thus avoiding any inconvenience that the presence of the flexible suction tube may interfere with an operating personnel.

When the coiler 30 is provided as shown in Figs. 8 and 9, a channel member which is Ushaped in longitudinal section may be secured to the lower end of the blackboard 1 in the same manner as in the previous embodiment, thus conveniently receiving the flexible tube which is reeled off the coiler 30 therein.

Claims (12)

1. A blackboard wiper assembly comprising an externally operated switch, a wiper having a suction hole formed therein, a dust collector located separate from the wiper, a suction tube providing communication between the suction hole in the wiper and the dust collector while permitting a movement of the wiper in any desired direction, and a suction motor located downstream of the dust collector, the motor being operated in response to an actuation of the switch.

2. A blackboard wiper assembly according to claim 1 in which the switch is disposed on the wiper.

3. A blackboard wiper assembly according to claim 1 in which the wiper is formed with suction holes around its outer periphery and in its inner portion.

4. A blackboard wiper assembly according to claim 3 in which the suction holes around the periphery are thinner in width than the inner suction hole.

5. A blackboard wiper assembly according to claim 1 in which the wiper includes a detachable wiper member.

6. A blackboard wiper assembly according to claim 1 in which the suction tube is flexible.

7. A blackboard wiper assembly according to claim 6 in which the flexible suction tube is adapted to be taken up on a coiler.

8. A black wiper assembly according to claim 6 in which the flexible suction tube is received in a channel member mounted on the bottom or the blackboard.

9. A blackboard wiper assembly according to claim 1 in which the dust collector includes a filter which separates chalk dust withdrawn together with the air.

10. A blackboard wiper assembly according to claim 9 in which the filter is oscillated in response to the operation of a motor or a vibrator.

11. A blackboard wiper assembly according to claim 10 in which the motor or the vibrator is set in motion for a given time interval in synchronized relationship with the termination of the operation of the suction motor.

12. A blackboard wiper assembly substantially as hereinbefore described with reference to the accompanying drawings.