a preferred embodiment of a comb of the invention is shown in fig1 where a cutaway view allows the essential characteristics to be seen . the comb comprises a handle with a first portion 10 which is held in the user &# 39 ; s hand containing a rotary electric motor 12 powered by the mains via a flex 14 . motor 12 turns a drive shaft 16 which acts as the shaft of a camshaft 18 located in a second portion 20 of the handle . in general , the camshaft 18 is made up of a run of cams in permanent contact with the ends of a set 22 of rigid teeth . when shaft 16 of camshaft 18 is rotated by electric motor 12 , the set of teeth 22 are caused to pivot or oscillate with respect to a fixed common shaft 24 in the second portion 20 of the handle . as will be seen , the motion of each tooth is different from that of the two teeth to which it is adjacent . when in use , the user keeps the set of teeth 22 in a horizontal position and activation of the motor causes the teeth to move , and because of their different motions , they comb out the hair . during combing out , the user can move the comb from top to bottom or back to front . in a preferred embodiment of the invention , the camshaft is made up of circular cams as shown in fig2 . each circular cam 30 or 32 is eccentrically fixed on a square section shaft 34 . in the embodiment shown in fig2 each cam is offset by an angle of 180 ° from the preceding cam , i . e ., all of the even cams are fixed the same way , and all of the odd cams are fixed the same way on the camshaft , and each set of cams is offset by 180 ° from the other . a tooth of the comb is engaged with its associated cam as shown in fig3 a . the tooth comprises a first portion 40 outside the handle which combs out the hair , and a second portion 42 in the form of a fork with two parallel prongs , the two integral portions 40 and 42 being articulated about fixed shaft 24 . the two prongs 43 , 45 of the portion 42 of the tooth surround cam 44 and remain in contact therewith . in the position shown in fig3 a , the tooth is at its highest point because the distance between shaft 34 and the tangent point 46 of cam 44 with the lower prong 45 of fork 42 is at its greatest . at the same time , with the disposition of the cams shown in fig2 where two adjacent cams are offset by an angle of 180 °, the two teeth adjacent the tooth shown in fig3 a are in the low position . as shaft 34 rotates in the direction of the arrow , the cam comes closer to the portion interconnecting the two prongs of the fork and is at a minimum distance ( which may be in contact ) when portion 40 is horizontal , i . e ., at the mid point of its oscillatory motion . shaft 34 continues to turn , and point 46 of the cam ( the point furthest from shaft 34 ) is at its highest point and is the tangent point of the cam with the upper prong 43 of fork 42 when portion 40 is in its lowest position . it can thus be seen that as fixed shaft 34 is rotated , each tooth oscillates or pivots with respect to fixed shaft 24 , the alternating motion or oscillations of two adjacent teeth being opposite ( or inverse ) if a camshaft such as that shown in fig2 is used . however , while still using circular cams which are eccentric to the drive shaft , the angular offsets between two adjacent cams can be adjusted to obtain a different tooth motion . thus , in contrast to the embodiment shown in fig2 where the oscillatory motions of two adjacent teeth are opposed , the cams fixed on the camshaft can be offset from the preceding cam by a smaller angle , for example 15 ° to 150 °, preferably 90 °. in this case , the oscillatory motion of each tooth is retarded relative to the oscillatory motion of the preceding tooth by an amount corresponding to this offset . thus the general movement of the set of teeth is a wavelike movement corresponding to the reduced offset between pairs of adjacent teeth . it has been shown that this motion , which is more gentle than the motion described above where the offset between the teeth is a maximum , is more comfortable and does not injure the hair . further , this motion produces a very agreeable sensation , especially in an individual with a particularly sensitive scalp . fig3 b shows a tooth with two non - parallel prongs 43 &# 39 ; and 45 &# 39 ; at its rear portion . in this case , cam 44 is not always in permanent contact with both prongs . as can be seen in fig3 c , the skilled person can readily replace the fixed shaft 24 by walls 25 of arcuate shape which confine the central portion 47 of each tooth between them , allowing them to perform oscillatory motion . in a second embodiment of the method of the invention , the desired effect can be obtained , namely combing out the hair . in this embodiment , the camshaft is replaced by a crankshaft 50 as shown in fig4 . each tooth 52 is hinged on a crank 54 of the crankshaft . because tooth 52 performs reverse motion ( or vice versa ) at the same time as it performs downwards motion ( or vice versa ) due to rotation of crank 54 of the crankshaft driving it , it includes an oblong hole 56 through which the fixed common shaft 24 passes , to give the shaft the required degree of freedom . rotary motion is thus imparted to portion 58 of the tooth which is in the hair , which is represented diagrammatically by a circular arrow in fig4 . this motion is offset ( by 180 °) from that of the two adjacent teeth . circular motion can be advantageous for certain types of hair for which simple vertical motion is not sufficient for combing out . fig5 a shows a tooth with an aperture 62 in place of a fork with two prongs . cam 44 is in permanent contact with the two parallel walls of aperture 62 . fig5 b shows a variation of the preceding embodiment , with camshaft 34 for cams 44 and fixed shaft 24 reversed . here , cam 44 is at its lowest point and thus the point of the tooth is also at its lowest point . fig6 is a longitudinal cross section of a tooth with centering studs 60 . each stud 60 nests in the female portion 61 of the neighboring tooth ( not shown ). fig7 a is a cross section of an appliance with multiple teeth or with different teeth . the appliance can have two series of teeth 40 and 40 &# 39 ;, one on each side of the drive mechanism 64 . fig7 b is a longitudinal cross section of the above with two adjacent teeth connected by centering studs . here , the teeth of the first series 40 , intended for combing out , are fewer and more spaced out than those of the opposite series 66 , intended for styling . fig8 a and 8b are two diagrams of two further embodiments , in which the teeth are substantially straight and each tooth is guided by a camshaft 34 , 44 and by a spring . spring 48 can be on the same side as the camshaft , as shown in fig8 a , and in this case it connects the rear end of the tooth to the wall and keeps the tooth in permanent contact with cam 44 by tension . it can equally well be on the side opposite the camshaft , as shown in fig8 b . in this case , a spring 48 &# 39 ; connects the rear end of the tooth to the wall opposite the camshaft and keeps the tooth in permanent contact with cam 44 by compression . fig8 c shows a further embodiment in which the spring of the preceding embodiment is replaced by a leaf spring 48 &# 34 ;. fig8 d and 8e show two further embodiments in which each tooth is guided by a camshaft and a pair of magnets . in fig8 d , two magnets of the same polarity ( in this case positive ) keep tooth 40 in permanent contact with cam 44 . in fig8 e , two magnets 49 &# 39 ; of opposite polarity attract to keep tooth 40 in permanent contact with cam 44 . fig9 shows a comb in which handle 10 containing electric motor 12 is perpendicular to camshaft 34 . the rotary motion is transmitted from shaft 16 of the motor to camshaft 34 by means of a worm . the comb of the invention may have teeth that are long or short , for example in the range 4 centimeters ( cm ) to 15 cm , and may have teeth of different lengths . the width of the tooth can , for example , be in the range 1 . 5 millimeters ( mm ) to 5 mm . their distance apart may be greater or smaller depending on the thickness of the hair to be combed out , an example being 2 mm to 6 mm . the teeth are preferably made of plastics material , but can be made of metal . they can be of any shape , with straight edges or with slightly shaped edges . the shaped form of the tooth shown in fig5 is perfectly suited to giving volume to a style . while a number of preferred embodiments have been described above , the skilled person is free to use any other drive means for the teeth in place of the camshaft or crankshaft without departing from the ambit of the invention .
an electric comb , particularly for combing out and styling difficult hair , comprises a plurality of teeth which are individually mounted and guided to make oscillatory movements . the comb is constituted by a handle , a casing containing the tooth drive mechanism , a series of teeth and an electric motor . the tooth drive mechanism is a shaft which is rotated by motor , comprising eccentric elements forming a camshaft . a second portion of each tooth comprises means for guiding the tooth by eccentric elements of the drive mechanism , which are formed , for example , by a fork with two prongs .