Method of manufacturing anchor fork for a trigger mechanism

Abstract

FIELD: watchmaking.SUBSTANCE: it is used to make an anchor fork. The method includes taking a strip of metal or metal alloy of thickness (e) and forming guide holes in the strip to guide the strip; milling the strip by at least half the thickness (e) of the strip to form horns; making a bevel to form the body of an anchor fork with a first end comprising horns and a second end comprising two arms, wherein the bevel is performed by at least half the thickness (e) of the strip, so that the body of the anchor fork still remains attached to the strip; milling the outer contour of the body of the anchor fork, wherein the milling is performed by two-thirds of the thickness (e) of the strip; milling a preliminary contour of a groove in each of the arms by the entire thickness (e) of the strip, wherein each of the grooves serves to receive a pallet, and at the same stage milling a preliminary contour of the shank; adjusting the grooves and the shank using a broaching tool; laser cutting of the resulting anchor fork to the thickness of the remaining strip to separate the anchor fork from the strip.EFFECT: simplifying the manufacture of an anchor fork.8 cl, 9 dwg

Description

[0001] Field of technology to which the invention relates

[0002] The present invention relates to the field of watchmaking. More specifically, it relates to a method for manufacturing a watch component, in particular a pallet fork for a watch escapement.

[0003] Technology Level

[0004] In the field of watchmaking, there are some cases where the use of complex components is required, the production of which requires numerous machining operations.

[0005] This applies, for example, to anchor forks, whose production requires numerous machining operations using multiple laser cutting machines. This method may require post-production adjustments, which is a costly and labor-intensive process.

[0006] Pallet forks of trigger mechanisms can also be made by stamping, but for small-scale production this method is very expensive and therefore of little interest.

[0007] Thus, one of the objects of the present invention is to provide a simpler manufacturing method that allows limiting the number of parts to be adjusted while maintaining the same number of machines required for machining the anchor forks.

[0008] Disclosure of the essence of the invention

[0009] To this end, the present invention relates to a method for manufacturing an anchor fork for a trigger mechanism.

[0010] According to the invention, the method includes the following steps:

[0011] a) taking a strip of metal or metal alloy and forming guide holes in the strip to guide the strip;

[0012] b) milling the strip to form horns;

[0013] c) making a bevel to form the body of the anchor fork with a first end containing horns and a second end containing two shoulders, wherein the bevel is made on a portion of the thickness of the strip so that the body of the anchor fork still remains attached to the strip;

[0014] d) milling the outer contour of the body of the anchor fork, whereby the milling is performed on a portion of the thickness of the strip, as in the previous stage;

[0015] e) milling a preliminary contour of a groove in each of the shoulders, each of the grooves serving to receive a pallet, and at the same stage milling a preliminary contour of the shank;

[0016] f) Adjusting the grooves and shank using a broaching tool;

[0017] g) laser cutting of the resulting anchor fork to the thickness of the remaining strip to separate the anchor fork from the strip.

[0018] According to other advantageous modifications of the invention:

[0019] - at step f), drawing is performed only in the axial direction;

[0020] - at step f) to obtain the specified width, at least two passes are performed in the lateral direction;

[0021] - at step e) also make a hole for the axle and a hole for the spear;

[0022] - at stage e) milling is performed across the entire thickness of the strip;

[0023] - the method includes step h), in which the pallets and axle are installed in the anchor fork;

[0024] - the broaching tool is made of hard metal.

[0025] The invention also relates to an anchor fork for a trigger mechanism obtained by the method according to the invention.

[0026] Brief description of drawings

[0027] Other characteristics and advantages of the invention will become apparent from the following detailed description with reference to the accompanying drawings.

[0028] Fig. 1 shows an anchor fork obtained by the method according to the invention;

[0029] Fig. 2-6a - various stages of the manufacturing method according to the invention.

[0030] Implementation of the invention

[0031] The present invention relates to the manufacture of a pallet fork for a trigger mechanism.

[0032] The anchor fork 1 comprises a body 2 formed of a metallic material, which may be, for example, carbon steel (e.g. 20AP, 15P, Ck75 or Ck101), titanium, aluminum, an austenitic cobalt alloy, a brass alloy (e.g. CuZn42) or a copper alloy (e.g. CuBe2 or nickel silver (CuNi18Zn20)).

[0033] Body 2 comprises arms 20 and 21 designed to support pallets for engagement with at least one escapement wheel (not shown) in the escapement mechanism. Between the two said arms 20 and 21, an escapement fork axle is installed in an opening 22 for mounting the escapement fork 1 with the ability to rotate. Finally, at the opposite end from arms 20, 21, body 2 comprises a shank 5 with two horns 50, 51.

[0034] The example in Fig. 1 shows a standard watch pallet fork. Of course, other types of pallet forks, such as a side pallet fork, can be made using the method described below.

[0035] Below, with reference to Fig. 2-6a, a description is given of the method 1 for manufacturing the anchor fork according to the invention.

[0036] The first step a) of the said method, shown in Fig. 2, consists of taking a strip 10 of metal or metal alloy of thickness e, in which guide holes 11 are made for guiding and moving the strip 10 along a conveyor (not shown in the figures).

[0037] The second step b), shown in Fig. 3, consists of milling 12 of the strip 10, wherein the milling 12 is performed to a depth that is less than the thickness e of the strip and is at least half the thickness e of the strip, to form the horns 50, 51 of the anchor fork.

[0038] The third step c) of the method, shown in Fig. 4 and 4a, consists of making a bevel to form the body of the anchor fork with a first end containing horns 50, 51, and a second end containing two shoulders 20, 21. The bevel is made to a depth equal to half the thickness e of the strip, so that at the end of this step the body of the anchor fork still remains attached to the strip.

[0039] The fourth step d) of the method consists of milling the outer contour of the body of the anchor fork, wherein the milling is also performed to a depth that is less than the thickness of the strip and is at least two-thirds of the thickness e of the strip, so that the body of the anchor fork remains attached to the strip.

[0040] The fifth step e), shown in Fig. 5 and 5a, consists of milling the preliminary contour of the groove 3, 4 in each of the shoulders 20, 21 and milling at the same step the preliminary contour of the shank 5. At this step, the grooves 3, 4 and the shank 5 are milled over the entire thickness e of the strip 10. At step e), a hole 22 for the axle and a hole 23 for the spear are also made.

[0041] The sixth step f), shown in Fig. 6, consists of adjusting the grooves 3 and 4 and the shank 5 using a broaching tool. Broaching is performed only in the axial direction, while at least two passes are made in the lateral direction to obtain the predetermined width of the grooves 3 and 4. This step allows for the desired angles to be obtained on the back side of the grooves, since milling cannot achieve the desired angles due to the cutter's radius being too large.

[0042] Finally, the seventh step (g) consists of laser cutting the resulting anchor fork to the thickness of the remaining strip to separate the anchor fork from the strip. Alternatively, the anchor fork can be separated from the strip using a stamp.

[0043] The method may also include step h), in which the pallets and axle are installed in the anchor fork.

[0044] The invention also relates to an anchor fork obtained by the method according to the invention.

Claims

1. A method for manufacturing an anchor fork (1) for a trigger mechanism, characterized in that it includes the following steps: a) taking a strip (10) of metal or metal alloy of thickness (e) and forming guide holes (11) in the strip (10) to guide the strip; b) milling (12) the strip (10) by at least half the thickness (e) of the strip (10) to form horns (50, 51); c) making a bevel to form a body (2) of an anchor fork with a first end comprising horns (50, 51) and a second end comprising two arms (20, 21), wherein the bevel is made over at least half the thickness (e) of the strip, so that the body of the anchor fork still remains attached to the strip; d) milling the outer contour of the body (2) of the anchor fork, whereby the milling is performed over two thirds of the thickness (e) of the strip; e) milling a preliminary contour of a groove (3, 4) in each of the shoulders (20, 21) over the entire thickness (e) of the strip, wherein each of the grooves (3, 4) serves to receive a pallet, and at the same stage milling a preliminary contour of the shank (5); f) adjustment of the grooves (3, 4) and the shank (5) using a broaching tool; g) laser cutting of the resulting anchor fork to the thickness of the remaining strip to separate the anchor fork from the strip.

2. The method according to paragraph 1, characterized in that at step f) the drawing is performed only in the axial direction.

3. The method according to claim 1 or 2, characterized in that in step f) at least two passes are made in the lateral direction to obtain the specified width.

4. The method according to any of paragraphs 1–3, characterized in that at step e) a hole (22) for the axle and a hole (23) for the spear are also made.

5. The method according to any of paragraphs 1–4, characterized in that at step e) milling is performed over the entire thickness of the strip.

6. The method according to any one of paragraphs 1–5, characterized in that it includes step h), in which the pallets and the axle are installed.

7. The method according to any of paragraphs 1–6, characterized in that the broaching tool is made of hard metal.

8. An anchor fork (1) obtained by the method according to any of paragraphs 1–7.

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