Expandable curler

Abstract

An expandable curler is provided to facilitate hair winding, because strain imparted by the curler to the hairs no longer depends on the strain applied by the operator during winding and where possible differences in strain caused by humidity or by drying are compensated by the curler, which consequently expands or contracts itself. The curler includes a body split in two or more rigid longitudinal sectors forming together a winding surface to receive an amount of wound hairs in a contracted configuration. Locking members of the sectors are also included in the contracted configuration and an elastic member, housed inside said sectors, are configured to apply a predetermined elastic force on said sectors, expanding the winding surface and determining a strain state at the wound hairs until reaching a balance between inner elastic force and strain applied to the wound hairs, when the locking members are deactivated.

1 . Expandable curler ( 1 ) comprising a curler body split in two or more rigid longitudinal sectors ( 2 ,  3 ) forming together a winding surface ( 4 ,  5 ) receiving an amount of wound hairs in a contracted configuration, further comprising locking members ( 9 ,  10 ) of said sectors ( 2 ,  3 ) in said contracted configuration and an elastic member ( 8 ), housed inside said sectors ( 2 ,  3 ), configured to apply a predetermined elastic force on said sectors ( 2 ,  3 ) expanding the winding surface ( 4 ,  5 ) and determining a strain state at the wound hairs until the reaching of a balance between inner elastic force and strain applied to the wound hairs, when said locking members ( 9 ,  10 ) are deactivated. 
     
     
         2 . Curler ( 1 ) according to  claim 1 , wherein the curler body is determined by matching two half-shells ( 2 ,  3 ) forming said rigid longitudinal sectors. 
     
     
         3 . Curler ( 1 ) according to  claim 1 , wherein the winding surface is substantially cylindrical. 
     
     
         4 . Curler ( 1 ) according to  claim 1 , wherein the curler body comprises retaining members that retain the hairs in their winded configuration. 
     
     
         5 . Curler ( 1 ) according to  claim 1 , wherein the elastic member comprises helical springs ( 8 ) inside said sectors ( 2 ,  3 ). 
     
     
         6 . Curler ( 1 ) according to  claim 1 , wherein the curler body comprises retaining members that prevent the disengagement of said sectors ( 2 ,  3 ). 
     
     
         7 . Curler ( 1 ) according to  claim 1 , wherein the locking members ( 9 ,  10 ) act on opposite ends of the curler body, to ensure the contraction along the whole length thereof. 
     
     
         8 . Curler ( 1 ) according to  claim 1 , wherein the curler body is made of inert material, plastic or metallic. 
     
     
         9 . Curler ( 1 ) according to  claim 1 , wherein the curler body comprises a heating element, to be activated during the hair treatment either to dry or to or to set the curled shape thereof. 
     
     
         10 . Curler ( 1 ) according to  claim 1 , wherein the expansion of the winding surface ( 4 ,  5 ) occurs by mutual pulling apart of the longitudinal sector ( 2 ,  3 ). 
     
     
         11 . Curler ( 1 ) according to  claim 1 , wherein said sectors ( 2 ,  3 ) expand the winding surface ( 4 ,  5 ) by mutual relative rotation of the sectors ( 2 ,  3 ) around a longitudinal axis with respect to an internal cam profile guiding the longitudinal sectors ( 2 ,  3 ) and/or by a peculiar shape of each sector ( 2 ,  3 ). 
     
     
         12 . Set of curlers ( 1 ) as claimed in  claim 1 , wherein the elastic member has different elastic constants, to apply more or less strain on the hairs according to either the treatment to be carried out or the desired effect.