FR2796733A1 - PUSH-BUTTON DEVICE - Google Patents

Abstract

Pusher device for a timepiece, comprising:. a tube (10), of generally cylindrical shape, intended to be assembled to a watch case and defining an axis,. a plunger (11) engaged and mounted axially to slide in said tube (10),. a coil spring (12) inserted between the tube (10) and the pusher (11), to generate an axial force, and. a radially deformable elastic member (13), axially integral with the pusher and cooperating with the said tube to define a click, in which the said pusher (11) comprises a body (25), to ensure the connection between the inside and the outside of the watch, and a head (26) to allow a user to actuate it, and said tube comprises an internal wall provided with a notch (23), The device according to the invention is characterized in that the elastic member (13) and the coil spring (12) overlap axially. Application to watch cases.

Description

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PUSH-BUTTON DEVICE

  The present invention relates to a push device, of the type intended to equip timepieces and more particularly watches. Such devices are well known to those skilled in the art. They allow the control of certain functions, such as starting, stopping and resetting a chronograph. The present invention relates more particularly to devices comprising a generally cylindrical tube intended to be assembled to a case, for example a watch case, and defining an axis, a pusher engaged and mounted axially sliding in the tube, a spring o coil inserted between the tube and the pusher, to generate an axial force and an elastic member, deformable radially and cooperating with the tube and the pusher to define a click. In this device, the pusher comprises a body, to ensure the connection between the outside and the inside of the watch, and a head rigidly fixed to the body and intended to be subjected to the pressure of

  User to control a function.

  Such a push device is for example described in US Patent 4,451,719. The elastic member is formed of a radially deformable split ring and an annular notch cooperating with the ring, one associated with the pusher, the other with the tube. An action on the pusher causes the deformation of the ring until its diameter is equal to that of the notch, the pressure exerted on the pusher increasing. As soon as the notch has passed, the pressure necessary to move the pusher suddenly drops. That

generates the desired click.

  This solution has a major drawback. Indeed, the assembly formed by the ring and the notch must be arranged axially beyond or below the coil spring. This considerably reduces the length of the latter. It follows that the deformation is of a significant amplitude with respect to the

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  length of the spring. In this way, the pressure exerted varies considerably

during movement of the pusher.

  One of the aims of the present invention is to overcome this drawback. This object is achieved thanks to the fact that the tube and the head have one an internal wall provided with a notch and the other a bearing surface against which the elastic member is in support, the elastic member and the coil spring

axially overlapping.

  In the patent application mentioned above, the ring defining the elastic member is formed from a coiled wire. This solution allows 1o better working conditions with the notch than a cut ring. It is unfortunately difficult to define its diameter with precision, and so

  control the force to be applied to the pusher.

  To better control this parameter, the elastic member according to the invention is formed of a washer, provided with a central opening engaged in the body is of the pusher, bearing against the bearing surface, and which carries at least two arm extending from the bearing surface to the inside of the tube, the free end of

  each arm cooperating with the internal wall of the tube or of the head.

  The present invention also aims to produce a device whose constituent parts can be machined by economical means,

  precise, simple and fast like bar turning or stamping for example.

  This object is achieved thanks to the fact that: - The elastic member is obtained by cutting, from a sheet of material

elastic of constant thickness.

  - The outer wall of the tube has two cylindrical portions, one disposed on the side opposite the head and intended to be engaged in the watch case and the other, arranged in the extension of the first and comprising, with said head , an overlap area, the diameter of the

  first portion being less than that of the second portion.

  In most watches, the pusher head at least partially covers the tube. With such an embodiment, it is advantageous that the

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  head forms the bearing surface and has an annular skirt surrounding the tube over a part of its length, and that the tube defines the internal wall provided

guts.

  It is easy to manufacture such tubes by turning, in particular when the internal wall of the tube comprises four successive cylindrical parts whose diameters go increasing from the inside of the box towards the head of the pusher and which define: * a slide in which is engaged the body of the pusher, * a housing for receiving the part of the coil spring opposite the head, and ò the first and second working surfaces of the elastic member,

connected by the notch.

  To guarantee a regular click, the difference in radius between the cylindrical parts of the first and second working surfaces is appreciably

  equal to half the thickness of the sheet forming the elastic member.

  In some watches, the pusher is protected by the tube, because the head is engaged inside the tube. In such an embodiment, the device according to the invention is arranged so that the head extends axially inside the tube and comprises a cylindrical skirt whose internal wall is

  provided with said notch, while the tube defines the bearing surface.

  In a particularly advantageous embodiment, the device comprises means ensuring its sealing. It includes, for this purpose, a

  gasket interposed between the tube and the pusher.

  In watches fitted with pushers, it is difficult to ensure water resistance, especially when they are activated. Another object of the present invention is to increase the pressure between the seal, the tube and the pusher during movement of the latter. To this end, the device according to the invention is characterized in that:

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  the tube is provided with a hole which comprises, on the side opposite to the head, a first sector of cylindrical shape whose diameter is adjusted to that of the body and, on the side of the head, a second sector, also cylindrical, and whose diameter is greater than the diameter of the first sector, the two sectors being interconnected by a flat surface, the device further comprises a ring interposed between the seal and the spring and against which the latter comes to bear, and - the seal is housed in the tube, in contact with the flat surface,

the body of the pusher and the ring.

  io Thanks to this configuration, the seal is compressed when the pusher is actuated. In this way, the seal is improved when the

button is activated.

  Depending on the wearing conditions, the device may become clogged, which could disturb its operation. This is why it may be advantageous to have a seal in such a way that it prevents water and dirt from entering the device. To this end, the head of the pusher comprises a skirt extending over part of the height of the tube and the seal is placed in a groove and cooperates with a cylindrical surface of axial dimension at least equal to the displacement of the pusher, the groove and the cylindrical surface being one formed in the skirt, the other in

  the outer wall of the tube, in its part opposite the skirt.

  The seal is a delicate organ. That is why it is necessary to protect it as much as possible. In order to subject it to a minimum of stresses, it can be placed alone, or in combination with another seal, in a groove in the body of the pusher, practiced in its mounted part.

  sliding in the tube, in contact with the wall of the latter.

  Other advantages and characteristics of the invention will emerge from the

  description which follows, made with reference to the appended drawing, in which

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  In Figures 1 and 2 show, in section, a device according to the invention, in the rest position and pressed respectively, and * Figures 3 and 4 illustrate two other embodiments, in the rest position. The pusher device as shown in FIGS. 1 and 2 essentially comprises a tube 10, a pusher 11, slidably mounted in the tube, a coil spring 12 intended to hold the pusher in the external position and an elastic member 13. It is in additionally provided with a seal 14 and a

ring 15.

  The tube 10 is advantageously made of stainless steel. It is intended to be engaged and fixed in a sealed manner in the middle of a watch case not shown in the drawing. It has an external wall having a first portion 16, conical, to facilitate the positioning of the device in the middle part, a second portion 17, cylindrical, intended to be in intimate contact with the wall of the hole of the middle part, shutting it off sealingly, and a third portion 18, also cylindrical and arranged outside the box. The tube 10 is pierced with a hole comprising four sectors 19, 20, 21 and 22, all cylindrical, their diameters increasing in the order indicated. The sector 19 is arranged in the part of the tube housed in the box. Its diameter is adjusted to the diameter of the body of the pusher, which slides there freely. The sector 20, adjacent, serves as a housing for the coil spring 12, the seal 14 and the ring 15, the latter two being arranged in the part adjacent to the portion 19. Its diameter is therefore slightly 2s greater than the outside diameter of the spring 12, to allow the latter to move freely therein. The spring 12 bears against the ring 15. The sectors 21 and 22 form the part of the tube 10 external to the box, entirely included in the portion 18. The sector 21 is connected to the sector 22

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  by a conical surface defining a notch 23. The difference in the radii of

  sectors 21 and 22 is between 0.05 and 0.10 mm.

  The pusher 11 comprises a body 25 and a head 26. The body 25 is formed of two cylindrical parts 27 and 28, coaxial, placed in the extension of one another and connected together by a flat surface 29. The part 28 is engaged in the cylindrical hole of sector 19 of the tube 10 and slides there freely. Its end outside the box has a thread 28a. Part 27 is intended to be housed inside the watch case, to ensure the connection between the pusher and the movement of the watch. Its diameter is larger than that of the part 28. It thus forms a stop and defines the contact between the pusher 11 and the tube 10, the flat surface 29 pressing against the end of the tube 10. Advantageously, it comprises a slot 27a allowing it to be rotated, so that it can be screwed and

  unscrew the assembly of the body 25 and the head 26.

  The head 26 is cup-shaped, with a bottom 30 and a cylindrical skirt 31. The bottom 30 is drilled in its center and inside the cup with a hole

  has tapped into which the thread 28a is screwed.

  The coil spring 12 is produced by means of a stainless steel wire of 0.25 mm in diameter. It has four to six turns and its unconstrained length is between 4 and 6 mm approximately. In place, it is permanently in support on the one hand against the elastic member 13, on the other hand

against the ring 15.

  The elastic member 13 is formed of a washer 32, pierced in its center with a hole 32a, the diameter of which is slightly larger than that of the part 28, and from which three arms 33 which form, with the washer, start. 32, an angle slightly greater than 90. These arms 33 extend from the washer 32 towards the interior of the box and bear by their ends 33a against the internal wall of the tube 10. They axially overlap the spring to

sausage 12.

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  The elastic member 13 is advantageously produced, by cutting and folding, in a stainless steel sheet having a thickness of 0.10 to 0. 20 mm and having a high elastic limit. The washer 32 is in abutment against the bottom 30 which forms a bearing surface 26a. The arms 33 are folded so that the circle in which their ends are inscribed has a diameter greater than 0.01 to 0.10 mm than the diameter of the sector 22. The angle at the top

  of the cone in which the notch 33 is inscribed is of the order of 120 to 130.

  With such a configuration, the pressure to be exerted to control the pusher is close to 7 to 12 N. io To assemble a device as described, the body 25 is first introduced into the tube 10. After which the gasket sealing 14, the ring 15 and the spring 12 are successively slid over the part 28 of the body 25. The elastic member 13 is then put in place by bending its arms 33 so as to make them penetrate the tube 10. The head 26 is screwed onto the body 25 by engagement of the threaded portion 28a in the threaded hole 30a. The device thus obtained forms a whole which can then without further be driven into a hole

  practiced for this purpose in the middle of the box.

  It is interesting to note that, since the coil spring 12 and the elastic member 13 overlap axially, it is possible to produce a pusher device having a coil spring occupying nearly 2/3 of its

length in rest position.

  The diameter of the tube in its part engaged in the box is of the order of 2 mm, which allows it to be used in practically all common applications. With the configuration described, the elastic member 13 and the notch 23 with which it collaborates are located in the part external to the box and are arranged radially beyond the coil spring 12. Despite this, the diameter of the head of the pusher has a completely acceptable value, since it is less than 4 mm. This is due to the fact that the arms of the elastic organ are very thin,

  which practically does not modify the radial dimension of the device.

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  At rest, the device occupies the position shown in FIG. 1. When the user of the watch exerts pressure on the head 26, it causes the push button 11 to sink. The ends 33a of the arms 33 slide over the surface of the sector 22 until reaching the notch 23. This offers resistance, so that the user must increase the pressure to overcome it, which causes the deformation of the arms 33 which flex so that the ends 33a pass the notch 23 and slide on the surface of the portion 21. At this stage, the pressure to be exerted drops suddenly, which

defines the click of the device.

  1o At the end of the race, the head 26 comes to butter, by its bottom 30, against the end of the

  tube 10, as shown in Figure 2.

  Under the effect of the pressure, the coil spring 12 is compressed, so that it brings back the pusher 15 as soon as the pressure is removed, until reaching the

  position shown in Figure 1.

  It is thus possible to obtain the click or detent effect as appreciated for the control of chronographs, at the same level as the push-button device. Despite this addition, the various parts constituting the device remain simple and easily machinable; their assembly is in

besides easy.

  When the pusher is actuated, the seal 14 is subjected to a pressure greater than that normally applied by the spring 12. This results in more intimate contact with the tube 10 and the pusher 11, which

  improves the tightness of the device.

  In the variant shown in Figure 3, the device comprises, identically to that shown in Figures 1 and 2, a tube 10 and a pusher 11, as well as a coil spring 12 interposed between the tube and the pusher. It differs from it in the way in which the sealing was achieved. The latter is provided by a seal 34, disposed in a groove 35 formed in the internal wall of the skirt 31 and in contact with the external wall of the tube 10 in its cylindrical portion 18. In this way the parts ensuring the function

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  clicks are located in the sealed space of the box, which prevents their functioning from being affected by perspiration or water that could enter. FIG. 4 represents another variant, in which the same parts have the same references as in FIGS. 1 to 3. This variant differs essentially in that the outside diameter of the skirt 31 is less than the inside diameter of the tube 10 in its portion 18, so that the pusher 11 penetrates inside the tube 10. With such a configuration, it is necessary to arrange the elastic member 13 differently. More precisely, the washer 32 of the member 13 is in support against the surface 36 connecting the

  sectors 19 and 20. The member 13 therefore remains fixed relative to the tube 11.

  To ensure the click function, the skirt 31 has on its internal wall 37, three sectors 38, 39 and 40. The sector 38, of cylindrical shape, is adjacent to the bottom 30. The sector 39 is of conical shape, with an angle at the top from 120 to 130. It performs the notch function, in cooperation with the arms 33. The third sector 40 is also of conical shape, but with a much more acute angle at the apex, for example between 20 and. This angle facilitates the positioning of the head 26 in the tube 10. In a variant not shown, it would also be possible to cut the internal angle of the free end of the skirt, the sector 40 then being able to be cylindrical. The body of the pusher 25 is fixed to the head 26 by welding or gluing. In this embodiment, the body 25 has, over its entire length, a diameter adjusted to the portion 19, with the exception of two grooves 41 and 42. The groove 41 is formed in the portion of the body 25 intended to be inside the watch case. It allows the engagement of a key 43, which ensures the locking of the pusher on the tube. The groove 42 is formed in the part of the body 25 permanently disposed in the portion 19 of the tube 10. It serves as a housing for a seal 44, which is therefore in intimate contact and

permanent with the wall of the tube 10.

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  The working conditions of the ends 33a of the arms 33 with the notch defined by the sector 39 are entirely comparable to the solution described with reference to Figures 1 to 3, except that in the case of the device of Figure 4, I he elastic member is fixed and it is the notch which moves with the pusher. With this embodiment, it is also possible to provide sealing in a manner comparable to the solution described with reference to Figures 1 to 3, or even to combine these solutions by providing the pusher with two seals. The solutions described can be the subject of numerous variants, without however departing from the scope of the invention. Thus, the number of arms of the elastic member could be reduced to two or on the contrary increased. Other materials could be used. The tube could, for example be made of brass and the elastic member made of a beryllium bronze alloy. It is also possible to provide a double seal by providing the device with two

  joints, by combining the arrangements shown in the drawing.

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Claims (12)

  1. Push device for a timepiece, comprising: * a tube (10), of generally cylindrical shape, intended to be assembled to a watch case and defining an axis, * a push button (11) engaged and mounted axially sliding in said tube (10), * a coil spring (12) interposed between the tube (10) and the pusher (11), to generate an axial force, and ò an elastic member (13) deformable radially, cooperating with the tube (10) and the pusher (11) to define a click, in which said pusher (11) comprises a body (25), to ensure the connection between the inside and the outside of the timepiece, and a head (26) to allow a user to actuate it, characterized in that said tube (10) and said head (26) one have an internal wall provided with a notch (23, 39), and the other a bearing surface against which the elastic member (13) bears, and in that this   last and the coil spring (12) overlap axially.   2. Push device according to claim 1, characterized in that said elastic member (13) is formed of a washer (32), provided with a central opening (32a) engaged in said body (25) and bearing against the bearing surface (30, 36), and which carries at least two arms (33) extending from the bearing surface inside the tube (10), the free end   (33a) of each arm being in abutment against said internal wall.   3. Pusher device according to claim 2, characterized in that said elastic member (13) is obtained by cutting from a sheet of   elastic material of constant thickness. 12 2796733   4. Pusher device according to one of claims 1 to 3, characterized in   that the outer wall of the tube (10) has two cylindrical portions, one (17) disposed on the side opposite the head (26) and intended to be engaged in the watch case and the other (18), arranged in the extension of the first and comprising, with said head, an overlap zone, the diameter of the first portion (17) being less than that of the second portion (18).   5. Pusher device according to one of claims 1 to 4, characterized in   0 that said head forms said bearing surface and has an annular skirt surrounding the tube over part of its length, and the tube   defines the internal wall provided with said notch.   6. Pusher device according to claim 5, characterized in that the internal wall of the tube (10) comprises four successive cylindrical sectors (19, 20, 21 and 22) whose diameters increase from the inside of the box towards the head (26) of the pusher and which define: * a slide (19) in which the body of the pusher is engaged, * a housing (20) for receiving the part of the coil spring (12) opposite the head, and * first and second working surfaces (21, 22) of the member   elastic (13), connected by said notch (23).   7. Pusher device according to claims 3 and 6, characterized in that   the difference in radius between the cylindrical parts of the first (21) and second (22) working surfaces is substantially equal to half of the thickness of said sheet. 13 2796733   8. Pusher device according to one of claims 1 to 4, characterized in   that said head comprises a cylindrical skirt (31) whose internal wall is provided with said notch (39) and which extends axially inside the tube   (10), the latter defining said bearing surface (36).   9. Pusher device according to one of claims 1 to 8, characterized in   that a seal (13, 34) is interposed between the tube (10) and the pusher (11).   10. Push device according to claim 9, characterized in that: * the tube (10) is provided with a hole which comprises, on the side opposite to the head (26), a first sector (19) of cylindrical shape of which the diameter is adjusted to that of said body (25) and, on the side of the head (26), a second sector (20), also cylindrical and whose diameter is greater than the diameter of the first sector (19), the two sectors being connected together by a flat surface (21), * the device further comprises a ring (14) interposed between the seal (13) and the spring (12) and against which the latter comes to bear, and * the seal seal (13) is housed in the tube (10), in contact with said flat surface (21), the body (25) of the pusher (11) and the ring (14).   11. Pusher device according to claims 9 or 10, characterized in   that the head (26) of the pusher comprises a skirt (31) extending over part of the height of the tube (10) and in that the seal (34) is disposed in a groove (35) and cooperates with a cylindrical surface (38) of axial dimension at least equal to the displacement of the pusher, the 14 2796733   groove and the cylindrical surface being one formed in the skirt (31), the other   in a wall (18) of the tube, in its part opposite the skirt (31).   12. Device according to one of claims 8 to 11, characterized in that   said body (25) has a groove (42) in its part slidably mounted in said tube (10), in which is housed a seal   seal (44) in contact with the wall of the tube (10).