Writing instrument

Abstract

A writing instrument comprises a barrel for accommodating a writing body and a sleeve attached to an outer circumferential face of the barrel and made of an elastic soft material. A plurality of ribs extending in the axial direction are formed on the outer circumferential surface of the barrel, a groove fitted to the rib is formed on an inner circumferential surface of the sleeve, and a gap portion is formed between the adjacent ribs between the sleeve and the barrel.

1 . A writing instrument having a barrel for accommodating a writing body and a sleeve attached to an outer circumferential surface of the barrel and made of an elastic soft material, comprising: 
 a plurality of first engaging portions provided on an inner circumferential surface of the sleeve extending in the axial direction and projecting in the direction of an inner diameter;    second engaging portions to be engaged with said first engaging portion formed on the outer circumferential surface of the barrel; and    a gap portion formed between said adjacent first engaging portions between the sleeve and the barrel.    
   
   
       2 . The writing instrument according to  claim 1 , wherein an outer profile shape of a cross section of said sleeve is a non-circular polygonal shape including a triangle or a shape with more than three angles in at least a part of a range in the axial direction, and said first engaging portion is formed on the inner circumferential surface portion corresponding to an angle portion of the polygonal shape.  
   
   
       3 . The writing instrument according to  claim 2 , wherein the outer profile shape of the cross section of said sleeve is a triangular shape.  
   
   
       4 . The writing instrument according to  claim 2 , wherein said sleeve has side portions and angle portions in said polygonal shape, the side portion has a small curvature and the angle portion has a large curvature.  
   
   
       5 . The writing instrument according to  claim 1 , wherein an outer profile shape of the cross section of said sleeve is varied according to the axial position at least in a part of a range in the axial direction.  
   
   
       6 . The writing instrument according to  claim 4 , wherein an outer profile shape of the cross section of said sleeve is varied so that the proportion shared by the side portions of said sleeve is continuously increased from the front to the rear.  
   
   
       7 . The writing instrument according to  claim 2 , wherein said barrel includes a front barrel to which said sleeve is attached and a rear barrel which is located in the rear of the front barrel, and an outer profile shape of a cross section of said rear barrel corresponds to the outer profile shape of a rear end of said sleeve forming a non-circular polygonal shape of triangle or a shape with more than three angles.  
   
   
       8 . The writing instrument according to  claim 7 , wherein a clip is mounted to the rear barrel, and the clip is mounted at a circumferential position aligning with one of the angle portions of the polygonal shape of the cross section of the sleeve and one of the angle portions of the polygonal shape of the cross section of the rear barrel.  
   
   
       9 . The writing instrument according to  claim 1 , wherein the second engaging portions of said barrel project from the outer circumferential surface of the barrel in the direction of an outer diameter.  
   
   
       10 . The writing instrument having a barrel and a sleeve attached to an outer circumferential surface of the barrel and made of an elastic soft material, wherein 
 either one of a plurality of ribs and grooves extending in the axial direction is formed on an inner circumferential surface of the sleeve, the other of the ribs and the grooves to be fitted in either one of the ribs and the grooves is formed on the outer circumferential surface of the barrel, and a gap portion is formed between the adjacent ribs between the sleeve and the barrel.    
   
   
       11 . A method for providing a cushion effect to a writing instrument having a barrel and a sleeve attached to an outer circumferential surface of the barrel and made of an elastic soft material, comprising 
 forming a plurality of first engaging portions on an inner circumferential surface of the sleeve extending in the axial direction and projecting in the direction of an inner diameter,    forming second engaging portions engaged with said first engaging portions on the outer circumferential surface of the barrel, and    forming a gap portion between said adjacent first engaging portions between the sleeve and the barrel.