Electric toothbrush

Abstract

It is desired to realize designing of a light, compact body and improved brushing effect and massage effect without causing any inconvenience, and to prevent the tip of a brush formed by a bristle bundle from remaining curled. A flexible diaphragm 13 which is displaced together with a reciprocative base 10 of a brush 9 is provided between a body space 2 and a brush guide passage 6 . An air introduction hole 15 having a valve 14 which opens only to the inside is formed in a midpoint of the brush guide passage 6 . When the diaphragm 13 is displaced toward the body space 2 with the reciprocation motion of the base 10 , air is introduced through the air introduction hole 15 into the brush guide passage 6 , which is now under negative pressure. When the diaphragm 13 is displaced toward the brush guide passage 6 , the introduced air is compressed and is ejected from the opening 6 a at the tip. Thus, the body can be designed lightly and compactly, and the brushing effect and the massage effect are improved without causing inconvenience.

1 . An electric toothbrush comprising a casing having therein a brush guide passage extending from one end side of a body space, a reciprocating motion source mounted in the body space, and a base mounted in said casing and coupled to the reciprocating motion source, said base being planted with a brush formed by a bristle bundle and extending toward a tip of the brush guide passage, said base being reciprocated toward the brush guide passage so that the tip of the brush moves in and out of an opening formed at the tip of the brush guide passage, characterized in that a flexible diaphragm which is displaced together with the reciprocative base is provided between the body space and the brush guide passage, and that an air introduction hole provided with a valve which opens only to the inside is formed in a midpoint of the brush guide passage, whereby when the diaphragm is displaced toward the body space with the reciprocating motion of the base, air is introduced into the brush guide passage, which is now under negative pressure, and when the diaphragm is displaced toward the brush guide passage, air introduced into the brush guide passage is compressed, and the compressed air is injected from the opening formed at the tip of the brush guide passage. 
   
   
       2 . The electric toothbrush according to  claim 1  further comprising a cleaning fluid tank mounted in the casing and storing a cleaning fluid, and means for discharging the cleaning fluid in the cleaning fluid tank into the brush guide passage. 
   
   
       3 . The electric toothbrush according to  claim 2  wherein the cleaning fluid is discharged into the brush guide passage near its tip. 
   
   
       4 . The electric toothbrush according to  claim 2  wherein said means for discharging the cleaning fluid in the cleaning fluid tank discharges the cleaning fluid in the cleaning fluid tank by introducing air in the brush guide passage, which is compressed when the diaphragm is displaced toward the brush guide passage, into the cleaning fluid tank. 
   
   
       5 . The electric toothbrush according to  claim 2  wherein the body space is hermetically closed, an air introduction hole provided with a valve which opens only to the inside is formed in a wall forming the body space, and the means for discharging the cleaning fluid in the cleaning fluid tank discharges the cleaning fluid in the cleaning fluid tank by introducing air from the air introduction hole to the body space, which is under negative pressure, when the diaphragm is displaced toward the brush guide passage, and by compressing air introduced into the body space and introducing the compressed air into the cleaning fluid tank when the diaphragm is displaced toward the body space. 
   
   
       6 . An electric toothbrush comprising a brush formed by a bristle bundle and reciprocated by a predetermined stroke along a brush guide passage having a bent portion so that the tip of the brush moves in and out of an opening formed at the tip of the brush guide passage, characterized in that a straight portion or a reverse bent portion which is bent in the direction opposite to the bent portion is provided on the tip side of the bent portion in the brush guide passage. 
   
   
       7 . The electric toothbrush according to  claim 6  wherein the straight portion or the inverse bent portion in the brush guide passage has a length equal to or larger than the stroke of the brush. 
   
   
       8 . The electric toothbrush according to  claim 6  wherein a cleaning hole for cleaning the brush in the passage is formed in a midpoint of the brush guide passage. 
   
   
       9 . The electric toothbrush according to  claim 3  wherein said means for discharging the cleaning fluid in the cleaning fluid tank discharges the cleaning fluid in the cleaning fluid tank by introducing air in the brush guide passage, which is compressed when the diaphragm is displaced toward the brush guide passage, into the cleaning fluid tank. 
   
   
       10 . The electric toothbrush according to  claim 3  wherein the body space is hermetically closed, an air introduction hole provided with a valve which opens only to the inside is formed in a wall forming the body space, and the means for discharging the cleaning fluid in the cleaning fluid tank discharges the cleaning fluid in the cleaning fluid tank by introducing air from the air introduction hole to the body space, which is under negative pressure, when the diaphragm is displaced toward the brush guide passage, and by compressing air introduced into the body space and introducing the compressed air into the cleaning fluid tank when the diaphragm is displaced toward the body space. 
   
   
       11 . The electric toothbrush according to  claim 7  wherein a cleaning hole for cleaning the brush in the passage is formed in a midpoint of the brush guide passage.