Patent Document

BACKGROUND OF THE INVENTION 
   The present invention relates to a handle for a tool, in particular for a screwdriver, of the type comprising a core adapted to be secured to a blade of the tool and a sleeve of plastics material placed around the core. The core and the sleeve having portions in relief for mutual positioning in rotation, and mutual positioning means for mutual positioning in axial translation. 
   This design makes it possible to implement a range of tools, in particular screwdrivers, at low cost and having different finishing layers, all starting from a single blank constituted by the core. 
   FR-A-2 730 658 proposes a screwdriver of the above-specified type in which the sleeve is overmolded onto the core fitted with the blade. 
   SUMMARY OF THE INVENTION 
   An object of the invention is to improve that tool so as to enable production throughput to be increased and also to increase reactivity, i.e. the ease with which the outer appearance of the tool can be modified, while simultaneously reducing manufacturing costs. 
   For this purpose, the invention provides a handle for a tool, in particular a screwdriver, of the above-specified type, characterized in that the sleeve is a part that is distinct from the core, being made of a semi-rigid plastics material and being engaged onto the core from in front. 
   The invention also provides a tool, in particular a screwdriver, having a handle as defined above and an extension, in particular a screwdriver blade, fixed in the handle. 
   The invention also provides a range of tools, in particular screwdrivers, in which all of the tools in the range are as defined above and the handles of all of the tools of the range have the same core and differ in the outside shape and/or the color and/or a coating and/or marking of the sleeve. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Embodiments of the invention are described below with reference to the accompanying drawings, in which: 
       FIG. 1  is an elevation view of a screwdriver constructed in accordance with the invention; 
       FIG. 2  is an end view from in front taken in section on line II—II of  FIG. 1 ; 
       FIG. 3  is an elevation of the core of the  FIG. 1  screwdriver; 
       FIG. 4  is an end view from in front of the core, seen looking along arrow IV in  FIG. 3 ; 
       FIG. 5  is an elevation view of the  FIG. 3  core after being turned through one-fourth of a turn about its own axis from the position of  FIG. 3 , together with an axial sectional view of the  FIG. 1  screwdriver sleeve ready for engaging on the core; 
       FIG. 6  is a cross-sectional of the assembled screwdriver, the section being taken on lines VI—VI of  FIG. 5 ; and 
       FIG. 7  shows details VII of  FIG. 5  on a larger scale, after the sleeve and the core have been assembled together. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   The screwdriver shown in the drawings has a general axis X—X and is constituted by four parts: a metal blade  1 , a core  2  of rigid plastics material, a sleeve  3  of semi-rigid plastics material, and a locking pin  4 . These parts are made separately and then assembled together mechanically. 
   In the text below, the words “front” and “rear” relate respectively to the distal and proximal ends of the handle, and to the right and left ends as shown in  FIGS. 1 ,  3 ,  5 , and  7 . 
   The core  2  is a solid body defining, going from front to rear: 
   a front portion  5  of small diameter that is substantially frustoconical, converging rearwards with a small angle at the apex α equal to about 0.2° to 1°, for example 0.5°, and whose front end face  6  is plane; 
   a fluted intermediate portion  7  comprising a forwardly-converging front region  8 A followed by a cylindrical rear region  8 B, and in which there are provided a plurality (six in this example) of longitudinally-extending cylindrical flutes  9 . Close to its rear end, the region  8 B has a radial shoulder  10  forming a step of slightly greater height. The portions  5  and  7  of the core are separated by a circular groove  11  having a radial front flank and a forwardly-converging rear flank; and 
   a rear knob  12  of roughly hemispherical shape, having a radial front face  13  joining the rear end of the region  8  and the fluting  9 . 
   The core  2  also has a localized portion in relief  14  projecting from the bottom of one of the flutes  9 . This portion in relief extends axially from the face  13  and presents a shape with an intermediate constriction when seen in plan view ( FIG. 5 ). The core is also provided with an axial blind hole  15  which extends from its front end to an intermediate shoulder of the portion  7 , and at the rear end of this hole  15  it has a radial blind hole  16  provided between two flutes  9  ( FIGS. 5 and 6 ). 
   The inside shape of the sleeve ( FIGS. 5 to 7 ) is complementary to the outside shape of the portions  5  and  7  of the core. In particular, the sleeve includes a front portion  17  converging rearwardly at the angle α, and a rear portion  18  having a rearwardly-diverging front region  19 A followed by a cylindrical rear region  19 B with six axial splines  20  projecting from its cylindrical inside surface. The portions  17  and  18  are separated by a circular rib  21  whose front flank is radial while its rear flank converges forwards ( FIG. 7 ). 
   At the rear end of one of the splines  20  there is provided an indentation  22  that is complementary to the portion in relief  14  on the core, and that is open rearwardly. 
   On the outside, the sleeve has a section which is circular in its portion  17  and which is roughly polygonal (square in this example) in its portion  18 . Its profile lengthwise ( FIG. 5 ) on going from front to rear convex, then concave, and then substantially parallel to the axis X—X. Each face of the portion  18  has portions in relief  23  with rounded edges formed thereon ( FIG. 1 ) for improving grip on the tool. 
   A stepped radial orifice  24  is formed through the sleeve between two splines  20 , and a hollow radial shoulder  25  is provided at the rear end of the cylindrical surface  19 B. 
   The core  2  and the sleeve  3  are made separately by injection molding, the sleeve is engaged on the core by being threaded on from in front (arrow F in  FIG. 5 ), with its indentation  22  in the same radial half-plane as the portion in relief  14 . The splines  20  penetrate into the fluting  9  until the shoulders  10  of the core come into abutment against the complementary shoulders  25  of the sleeve. At the end of this movement, the portion in relief  14  snaps into the indentation  22  and the rib  21  snaps into the groove  11 . The front end of the sleeve is then substantially in register with the end face  6  of the core, leaving the end face visible. 
   The sleeve is then prevented from turning relative to the core by the splines  20  and the fluting  9 , and it is locked in translation, rearwards by the shoulders  10 , and forwards by three means: firstly by co-operation between the rib  21  and the groove  11 ; secondly by the undercut surfaces  5  and  17 ; and finally by the portion in relief  14  snap-fastening in the indentation  22 . 
   To supplement and to reinforce this locking arrangement, the pin  4  is forced through the orifice  24  and into the hole  16  in the core ( FIG. 6 ). 
   The assembly operations, including force-fitting the rear portion of the blade  1  in the axial hole  15  of the core, can be performed automatically. The same applies to marking the sleeve which is easy to take hold of and to manipulate because it is semi-rigid. 
   The term “semi-rigid” is used to mean that it has the property of being substantially undeformable, while nevertheless being sufficiently elastic to deform slightly under the action of high forces of the kind developed in a press (i.e., when the sleeve is press-fitted on the core). This is in contrast both to the almost completely rigid core material, and to the flexibility of elastomers. 
   By way of example, the core can be made of polypropylene or of cellulose acetate, while the sleeve can be made of soft polypropylene which is a material sold under the trade name “Santoprene”. 
   Depending on the application, recourse may be had to any appropriate combination of the four axial locking means described above (5-17, 11-21, 14-22, and 4-16-23). The first three locking means are completely hidden by the sleeve, while the pin  4  is visible in its orifice  24  and can then be used for color coding. 
   In a variant, the sleeve may be made as a composite part having part or all of its outside surface covered in a more flexible surface layer for gripping purposes, as referenced  26  in  FIG. 1 . 
   In another variant, the core  2  may be overmolded on the blade  1 .

Technology Category: 7