Abstract:
A spiral spring for use in connection with horology instruments is disclosed which includes a spiral spring and a collet which are produced in one piece without molecular discontinuity.

Description:
FIELD OF THE INVENTION 
   The present invention relates to a spiral spring for a horology instrument for measuring time. 
   BACKGROUND OF THE INVENTION 
   The spiral springs usually used in horology are made up of several parts, which have to be produced with great accuracy and then assembled to form a composite part. The complexity of the production of such parts generates high costs and complex adjustments. 
   One object of the present invention is to propose a spiral spring with as low a production cost as possible and, if possible, without any operating defects. 
   SUMMARY OF THE INVENTION 
   In accordance with the present invention, this and other objects have now been realized by the invention of a spiral spring for use in a time measuring device comprising a spiral spring body and a collet produced in one piece and without molecular discontinuity between the spiral spring body and the collet. In a preferred embodiment, the spiral spring includes a terminal curve and a stud, wherein the terminal curve and the stud are also produced in one piece and without molecular discontinuity with the spiral spring body and the collet. 
   In accordance with one embodiment of the spiral spring of the present invention, the spiral spring body comprises a leaf having a predetermined height, and the stud comprises a circular cylinder having a height which corresponds to the predetermined height. 
   In accordance with another embodiment of the spiral spring of the present invention, the spiral spring body comprises a leaf having a predetermined width, and the stud has a width which is greater than the predetermined width and a degree of flexibility enabling the stud to be inserted by friction into a cavity. 
   In accordance with another embodiment of the spiral spring of the present invention, the stud comprises a pair of flexible circular arms. 
   In accordance with a preferred embodiment of the spiral spring of the present invention, the spiral spring includes a support including a first aperture and a second aperture crossing the first aperture, the stud being inserted by friction into the first aperture and being locked in the support by releasing its elastic tension in the second aperture. 
   In accordance with another embodiment of the spiral spring of the present invention, the collet includes a slot and a pair of open areas permitting the spiral spring to be balanced statically and to be gripped with an assembly tool. Preferably, the collet includes notches in its peripheral area. 
   In accordance with another embodiment of the spiral spring of the present invention, the stud comprises a widened extremity at the end of the spiral spring body and at least one notch thereon, and including a support containing a screw and a bearing bush, whereby the at least one notch in the extremity meshes with the threads of the screw and the bearing bush serves as a point of attachment for the spiral spring body. 
   In accordance with another embodiment of the spiral spring of the present invention, the spiral spring is produced by a single operation. Preferably, the single operation comprises an operation selected from the group consisting of micromolding, molding by means of molds produced by the exposure of UV-sensitive resins, galvanic deposition processes, galvanic deposition processes with a mold, projection of material, conventional cutting, laser cutting, wire EDM, die-sinking EDM, stamping, and the cutting of sheets utilizing a high pressure liquid jet. 
   The spiral spring in accordance with the present invention is entirely produced in one piece without molecular discontinuity with its collet. 
   A high quality, perfectly balanced part has been produced with the spiral spring in accordance with the present invention. The fact that it was produced all in one piece without discontinuity avoids defects inherent in conventional production, and in particular avoids internal stresses in the material and a lack of accuracy in the assembly of the constituent parts. Moreover, the cost of the spiral spring in accordance with the present invention is considerably reduced relative to the springs of the prior art. 
   The production of the spiral spring in accordance with the present invention can be carried out advantageously using known techniques, for example through macromolding operations, by molding with molds made by the exposure of UV-sensitive resins, by galvanic deposition processes with or without a mold, by the projection of material or by conventional cutting, particularly by laser, wire EDM or die-sinking EDM, by stamping or by the cutting of sheets of material by a high-pressure liquid jet. 
   The spiral spring may have a stud, also made all in one piece without molecular discontinuity with its terminal curve. The stud may be in the form of a circular cylinder with the same height as the leaf of the spiral spring. The stud may be in the form of a part which is wider than the leaf, offering a certain flexibility allowing it to be inserted by friction into a cavity, and the wider part may be produced in the form of two flexible circular arms. The stud may be inserted by friction into a hole in a support, with the stud being locked by releasing its elastic tension in a hole that is perpendicular to or axially crosses the hole made in the support. 
   In the spiral spring in accordance with one embodiment of the present invention, the collet has a slot and two openings allowing for the part to be statically balanced and gripped with an assembly tool. 
   The collet may also have reference notches around its edge. 
   The extremity produced all in one piece with the terminal curve may have one or more notches that mesh with the thread of a screw, the screw being held axially in the support and a bearing bush housed in the support being used as a point of attachment for the spiral. 
   Finally, the spiral spring may be produced by micromolding techniques, by molding with molds made by the exposure of UV-sensitive resins, by galvanic deposition processes with or without a mold, by the projection of material or by conventional cutting, particularly by laser, wire EDM or die-sinking EDM, by stamping or by the cutting of sheets of material by high-pressure liquid jet. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention may be more fully understood with reference to the following detailed description, which demonstrates several methods of implementation of the spiral spring in accordance with the invention, with reference to the drawings in which: 
       FIG. 1  is a top, elevational view of one embodiment of the spiral spring according to the present invention; 
       FIG. 2  is a top, elevational view of another embodiment of the spiral spring of the present invention; 
       FIG. 3  is a side, perspective view of a stud placed at the outside extremity of the spiral spring of the present invention; 
       FIG. 4  is a top, elevational view of another embodiment of the stud shown in  FIG. 3 ; 
       FIG. 5  is top, elevational, schematic view of a point of attachment for the stud shown in  FIG. 4 , which can be fixed to a conventional stud holder or to the bottom plate of a clock or to a balance bridge; 
       FIG. 6  is a top, elevational, partial view of one embodiment of the collet used in the spiral spring of the present invention; 
       FIG. 7  is a top, elevational, partially sectional view of another embodiment of the collet shown in  FIG. 6 ; and 
       FIG. 8  is a top, elevational, partially sectional view of another embodiment of the spiral spring of the present invention and its adjustment. 
   

   DETAILED DESCRIPTION 
   The spiral spring shown in  FIG. 1  is made up of a leaf  11  with a collet  12  in its center and a terminal curve  13  at its outside extremity. 
   The part shown in  FIG. 1 , with its components,  11 ,  12 , and  13 , is made all in one piece without discontinuity in its molecular structure. 
   It can be made using the following techniques: 
   Macromolding technique, consisting of depositing a metal inside a mold using a galvanic process. 
   By the projection of metal onto a base. 
   By conventional cutting of a sheet of material. 
   By cutting of a sheet of material by high-pressure liquid jet. 
   The application of the techniques mentioned above were used to produce the spiral spring shown in  FIG. 1  and the variants shown in  FIGS. 2 and 3 , with satisfactory results. They were used to obtain the spiral springs in accordance with the present invention all in one piece and without molecular discontinuity. The macromolding production technique in particular gave excellent results. 
   As shown in  FIG. 1 , the collet  12  is in the form of a large circular ring and has a slot  14  enabling it to be driven onto a pin without splitting and without buckling on assembly. 
   The variant shown in  FIG. 2  shows the spiral spring  11  with its collet  12  with a slot  14  and its terminal curve  13 . 
   At the extremity of the terminal curve  13  there is a circular stud  15  made all in one piece without molecular discontinuity with the spiral and its collet; obviously, the shape of the stud  15  is not restricted to a circuit configuration and the stud may be made in any shape desired, for example in a circular shape with a slot as in traditional horology, or in any other suitable geometric shape, and a hole can be made in the center of the knob on the extremity to facilitate its fixing. 
   The stud  15  in  FIG. 2  is shown in perspective and on a larger scale in  FIG. 3 . 
     FIG. 4  shows a variant of the stud  15 , which has two circular arms  16  and  17  with a certain flexibility. The stud in  FIG. 4  may, given its flexible nature, be inserted by friction into a hole  13  in a movable stud holder  19  or a bottom plate  19  of the horology part. The part  19  has a perpendicular hole  20  in which the stud  15  in the method of implementation shown in  FIG. 4  is locked, after the arms  16  and  17  have returned to their initial positions. 
   The collet  12  shown in  FIG. 6  with its slot  14  has two openings  21  and  22  used firstly to provide static balance to the assembly made up of the leaf  11 , the collet and, depending on the case, the terminal curve  13 , and secondly to facilitate the manipulation and gripping of the part with a tool. 
   In the variant shown in  FIG. 7 , a number of notches are used to distinguish the type of spiral spring.  FIG. 7  shows three notches  23 ; however, the shape and number of the notches can be chosen as needed. The method of implementation shown in  FIG. 3  has a spiral ring  30  like the spring in the previous methods of implementation, with its collet  12 , the slot  14  and its terminal curve  13 . 
   Here, as shown in  FIG. 8 , the stud is in the form of a widened extremity  31  produced without molecular discontinuity with the terminal curve  13 . The extremity  31  has notches  32  that mesh with the thread on a screw  33  held by means of two pins  34  inside a hole  35  in a support  36 . 
   The part opposite the teeth  32  of the extremity  31  has a smooth surface  37  allowing the extremity  31  to slide against a surface  38  on the support  36  under the rotating action of the screw  33 . The rotation of the screw  33  is therefore used to adjust the position of the extremity  31  in order to vary the active length of the terminal curve  13 . 
   A bearing bush  39  made of a synthetic material or of metal is used to hold the point of attachment  40  of the spiral laterally by friction. 
   The method of implementation that has just been described and the previous methods of implementation were produced advantageously from a non-magnetic stainless metal alloy using the macromolding method. 
   Although the invention herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present invention. It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims.