[ 0026 ] fig1 shows a front perspective view of an electric toothbrush according to a first embodiment of the present invention , generally designated as 10 . the toothbrush 10 includes an elongate handle 12 including a slidable button 14 operable to activate or deactivate the toothbrush 10 , as desired . extending from an upper end of the handle 12 is a hollow elongate tube 16 , which leads to a brush head 18 , with a number of bristles 20 for brushing . the brush head 18 is fixedly engaged with a shaft ( to be discussed below ) which extends through the hollow elongate tube 16 into the interior of the toothbrush 10 for engagement with a first coupling mechanism , to be discussed below . housed in the handle 12 is a motor ( to be discussed below ) powerable by one or more dry batteries ( not shown ) also contained in the handle 12 , or by an a . c . source . as shown in fig2 a and 2b , an electric motor 22 housed in the handle 12 has an output spindle 24 which is fixedly fitted in an opening 26 of a revolving disc 28 . extending from and fixedly secured with an upper surface 30 of the disc 28 is a pin 32 , which is received within an underside of a reciprocating block 34 , in a manner to be discussed below . it can be seen that , when the motor 22 is activated , rotation of the spindle 24 will cause the disc 28 and the accompanying pin 32 to revolve about the longitudinal axis of the spindle 24 . the reciprocating block 34 has , on its upper part , a channel 36 running along its length . the channel 36 is generally circular in shape , but with a flat bottom surface 38 . a correspondingly sized and shaped generally cylindrical rod 40 is received within the channel 36 . as the rod 40 also has a partly flat outer surface which abuts the flat bottom surface 38 of the channel 36 , the block 34 may only slide relative to the rod 40 along its length , with no relative swivelling or rotational movement . although it is preferred to provide a flat bottom surface 38 in the channel 36 and a partly flat outer surface on the rod 40 which complement with each other , both flat surfaces may be dispensed with without significantly affecting the performance of the coupling mechanism . as shown in fig2 a , the block 34 is hung and received within a cavity 42 of a top - open container 44 by the rod 40 for reciprocating movement . in particular , the container 44 has two ears 46 positioned on the upper edge of two opposite side walls 48 . each ear 46 has a hole 50 shaped and sized as the channel 36 of the reciprocating block 34 . thus , when the block 34 is placed in the cavity 42 of the container 44 , the rod 40 may be inserted through a hole 50 of one ear 46 , then through the channel 36 , and subsequently through the hole 50 of another ear 46 . by way of such an arrangement , the block 34 is hung within the cavity 42 for reciprocating movement relative to the rod 40 , and along an axis parallel to the length of the rod 40 . on each lateral side of the block 34 is a row of gear teeth 52 a , 56 b . the gear teeth 52 b are in mesh with a gear 54 fixed to a shaft 56 . the brush head 18 is fixedly engaged with an upper end of the shaft 56 for simultaneous movement . by way of such an arrangement , reciprocating movement of the block 34 will set the shaft 56 , and thus the brush head 18 , into swivelling movement about its longitudinal axis . it can also be seen that the longitudinal axis of the shaft 56 is perpendicular to the rod 40 . [ 0031 ] fig3 a to 3 d show various views of the reciprocating block 34 . as can be seen more particularly in fig3 c , an elongate recess 58 is formed on an underside of the block 34 for receiving part of the pin 32 of the disc 28 . the recess 58 is of a width that is the same or slightly larger than the diameter of the pin 32 , to allow sliding movement of the pin 32 relative to the recess 58 . it can also be seen that the length of the recess 58 is perpendicular to the length of the block 34 . [ 0032 ] fig4 a to 4 d show respective plan views of the relative position between the gear 54 , the block 34 , the rod 40 and the revolving disc 28 of the toothbrush 10 . it should be pointed out that the position of the longitudinal axis of the shaft 56 , and thus of the gear 54 , the longitudinal axis of the output spindle 24 of the motor 22 , and the rod 40 are fixed relative to one another . [ 0033 ] fig4 a shows the block 34 in the right - most position relative to the rod 40 . when the motor 22 is activated , the spindle 24 rotates so that the pin 32 of the disc 28 revolves around the longitudinal axis of the spindle 24 in the direction indicated by the arrow g , until the pin 32 reaches the position shown in fig4 b . as the pin 32 is confined within the recess 58 of the block 34 , and the movement of the block 34 is confined by the rod 40 , the block 34 will slide relative to the rod 40 in the direction indicated by the arrow h , thus causing the gear 54 , and the shaft 56 with which the gear 54 is secured , to rotate in the direction indicated by the arrow k . when the spindle 24 further rotates , the pin 32 will revolve around the spindle 24 in the direction indicated by the arrow j shown in fig4 b , until the pin 32 reaches the position shown in fig4 c . it can be seen that the block 34 has moved further relative to the rod 40 in the direction of the arrow h , and the gear 54 has rotated further in the direction indicated by the arrow k . in particular , in the position shown in fig4 c , the block 34 is in the left - most position relative to the rod 40 . when the pin 32 further revolves around the spindle 24 in the direction shown by the arrow m in fig4 c , the block 34 will start to move in the direction shown by the arrow p in fig4 c , which is opposite to the direction indicated by the arrow h in fig4 a , and the gear 54 will start to rotate about its own longitudinal axis in the direction indicated by the arrow q , which is opposite to the direction indicated by the arrow k in fig4 a . further rotation of the pin 32 relative to the spindle 24 in the direction of the arrow m shown in fig4 c will bring the pin 32 to the position shown in fig4 d , thus causing the block 34 to slide relative to the rod 40 further in the direction indicated by the arrow p , which in turn causes the gear 54 to rotate further about its longitudinal axis in the direction indicated by the arrow q . further rotation of the spindle 24 in the same direction will bring the pin 32 back to the position shown in fig4 a , thus completing a cycle of rotational movement . it can be seen that , by way of the coupling mechanism discussed above , upon activation of the motor 22 , the spindle 24 will rotate , thus causing the block 34 to reciprocate along the rod 40 , which in turn causes the gear 54 , and the brush head 18 fixed thereto , to swivel back and forth about the longitudinal axis of the shaft 56 . a second coupling mechanism suitable for use in an electric toothbrush according to the present invention is shown in fig5 a and 5b . an electric motor 122 housed inside the toothbrush has an output spindle 124 which is fixedly fitted with a revolving block 128 for simultaneous rotational movement . extending from and fixed with an upper surface 130 of the block 128 is a pin 132 , which is received within an underside of a reciprocating block 134 , in a manner to be discussed below . when the motor 122 is activated , rotation of the spindle 124 will cause the revolving block 128 and the accompanying pin 132 to revolve about the longitudinal axis of the spindle 124 . the reciprocating block 134 has a generally circular channel 136 running through its body . a correspondingly sized and shaped generally cylindrical rod 140 is received within the channel 136 , for allowing the block 134 to slide relative to the rod 140 . the block 134 is hung and received within a cavity 142 of a top - open container 144 by the rod 140 for reciprocating movement . in particular , the container 144 has two ears 146 positioned on the upper edge of two opposite side walls 148 . each ear 146 has a hole 150 shaped and sized as the channel 136 of the reciprocating block 134 . thus , when the block 134 is placed in the cavity 142 of the container 144 , the rod 140 may be inserted through a hole 150 of one ear 146 , then through the channel 136 , and subsequently through the hole 150 of another ear 146 . by way of such an arrangement , the block 134 is hung within the cavity 142 for reciprocating movement relative to , and along an axis parallel to the length of , the rod 140 . a pin 102 is received within a hole 106 of the block 134 for simultaneous reciprocating movement with the block 134 . the pin 102 extends upward from the reciprocating block 134 , and its top end is received within an underside of a swiveling block 104 for relative movement , in a manner to be discussed below . a shaft 156 is fixedly received within a hole 108 of the swiveling block 104 for simultaneous swiveling movement . a brush head ( not shown ) is fixedly engaged with an upper end of the shaft 156 for simultaneous movement . by way of such an arrangement , reciprocating movement of the block 134 will set the shaft 156 , and thus the brush head , into swiveling movement about its longitudinal axis . it can also be seen that the longitudinal axis of the shaft 156 is perpendicular to the rod 140 . [ 0040 ] fig6 a to 6 d show various views of the reciprocating block 134 . as can be seen more particularly in fig6 d , an elongate recess 158 is formed on an underside of the block 134 for receiving part of the pin 132 of the revolving block 128 . the recess 158 is of a width that is the same or slightly larger than the diameter of the pin 132 , to allow sliding movement of the pin 132 relative to the recess 158 . [ 0041 ] fig7 a to 7 d show various views of the swiveling block 104 . as can be seen more clearly in fig7 d , an elongate recess 110 is formed on an underside of the block 104 for receiving the upper end of the pin 102 extending from the reciprocating block 134 . the recess 110 is of a width that is the same or slightly larger than the diameter of the pin 102 , to allow sliding movement of the pin relative to the recess 110 . it can be seen that the recess 110 is parallel to the length of the swiveling block 104 . [ 0042 ] fig8 a to 8 d show respective plan views of the relative position between the swiveling block 104 , the reciprocating block 134 , the rod 140 and the revolving block 128 ( shown in dashed line ) of the toothbrush . it should be pointed out that the position of the longitudinal axis of the shaft 156 , the longitudinal axis of the output spindle 124 of the motor 122 , and the rod 140 are fixed relative to one another . [ 0043 ] fig8 a shows the block 134 in the right - most position relative to the rod 140 . when the motor 122 is activated , the spindle 124 rotates so that the pin 132 of the block 128 revolves about the longitudinal axis of the spindle 124 in the direction indicated by the arrow g ′, until the pin 132 reaches the position shown in fig8 b . as the pin 132 is confined within the recess 158 of the reciprocating block 134 , and the movement of the block 134 is confined by the rod 140 , the block 134 will slide relative to the rod 140 in the direction indicated by the arrow h ′. the movement of the block 134 will cause the pin 102 to also move in the direction indicated by the arrow h ′. because of the confinement of the pin 102 in the recess 110 of the swiveling block 104 , the swiveling block 104 , and thus the shaft 156 with which it is secured , will be caused to swivel in the direction indicated by the arrow k ′ about the axis of the shaft 156 . when the spindle 124 further rotates , the pin 132 will revolve around the spindle 124 in the direction indicated by the arrow j ′ shown in fig8 b , until the pin 132 reaches the position shown in fig8 c . it can be seen that the block 134 has moved further relative to the rod 140 in the direction of the arrow h ′, and the swiveling block 104 has rotated further in the direction indicated by the arrow k ′. in particular , in the position shown in fig8 c , the block 134 is in the left - most position relative to the rod 140 . when the pin 132 further revolves around the spindle 124 in the direction shown by the arrow m ′ in fig8 c , the block 134 will start to move in the direction shown by the arrow p ′ in fig8 c , which is opposite to the direction indicated by the arrow h ′ in fig8 a , and the swiveling block 104 will start to rotate about the longitudinal axis of the shaft 156 in the direction indicated by the arrow q ′, which is opposite to the direction indicated by the arrow k ′ in fig8 a . further rotation of the pin 132 relative to the spindle 124 in the direction of the arrow m ′ shown in fig8 c will bring the pin 132 to the position shown in fig8 d , thus causing the reciprocating block 134 to slide relative to the rod 140 further in the direction indicated by the arrow p ′, which in turn causes the swiveling block 104 to rotate further about the longitudinal axis of the shaft 156 in the direction indicated by the arrow q ′. further rotation of the spindle 124 in the same direction will bring the pin 132 back to the position shown in fig8 a , thus completing a cycle of rotational movement . it can be seen that , by way of the coupling mechanism discussed above , upon activation of the motor 122 , the spindle 124 will rotate , thus causing the block 134 to reciprocate along the rod 140 , which in turn causes the swiveling block 104 , and the brush head fixed thereto , to swivel back and forth about the longitudinal axis of the shaft 156 . it should be understood that the above only illustrates examples whereby the present invention may be carried out , and that various modifications and / or alterations may be made thereto without departing from the spirit of the invention . it should also be understood that certain features of the invention , which are , for clarity , described in the context of separate embodiments , may be provided in combination in a single embodiment . conversely , various features of the invention which are , for brevity , described in the context of a single embodiment , may also be provided separately or in any appropriate sub - combinations .
an electric toothbrush is disclosed as including an electric motor , a shaft engaged with a brush head , and a coupling mechanism operatively associated with the motor and the shaft for coupling with the motor to drive the shaft to swivel about a longitudinal axis of the shaft , the coupling mechanism including a reciprocating block reciprocable along a straight line perpendicular to the longitudinal axis of the shaft .