US3844108A

US3844108A - Mechanical watch movement

Info

Publication number: US3844108A
Application number: US00465664A
Authority: US
Inventors: P Bachmann
Original assignee: Ebauches Bettlach SA
Current assignee: Ebauches Bettlach SA
Priority date: 1973-05-11
Filing date: 1974-04-30
Publication date: 1974-10-29
Anticipated expiration: 1991-10-29
Also published as: CH582370B5; JPS579032B2; DE2422051C2; CH672973A4; JPS5054355A; DE2422051A1

Abstract

A mechanical watch movement with conventional elements and an improved click for retaining a ratchet-wheel, wherein the click is a blanked flat plate having an arcuate indentation in one of its edges, said indentation engaging a cylindrical bearing surface of a spacing pillar at the level of the ratchet wheel, and a resilient element acting upon the click, said resilient element being an arm blanked in a plate integral with the frame of the movement.

Description

United States Patent [1 1 Bachmann MECHANICAL WATCH MOVEMENT [75] Inventor: Peter Bachmann, Bettlach,

Switzerland [73] Assignee: Ebauches Bettlach S.A., Bettlach (Canton of Soleure), Switzerland [22] Filed: Apr. 30, 1974 [21] App]. No.: 465,664

[30] Foreign Application Priority Data May ll, 1973 Switzerland 6729/73 [52] U.S. Cl. 58/59 [51] Int. Cl. G04b 33/00 [58] Field of Search 58/59, 80, 82

[56] References Cited UNITED STATES PATENTS 2,758,489 8/1956 Junghans et al. 58/82 A X Oct. 29, 1974 Primary Examiner-George H. Miller, Jr. Attorney, Agent, or FirmStevens, Davis, Miller & Mosher [5 7] ABSTRACT A mechanical watch movement with conventional elements and an improved click for retaining a ratchetwheel, wherein the click is a blanked flat plate having an arcuate indentation in one of its edges, said indentation engaging a cylindrical bearing surface of a spacing pillar at the level of the ratchet wheel, and a resilient element acting upon the click, said resilient element being an arm blanked in a plate integral with the frame of the movement.

8 Claims, 2 Drawing Figures PATENTEDUBT 29 mm 3.844; 108

sum

1 or 2 MECHANICAL WATCH MOVEMENT This invention relates to a mechanical watchmovement comprising a mainspring fitted in a barreldrum rotating around a barrel-arbor, an inner member to which the mainspring is hooked, a ratchet-wheel integral in rotation with the inner member, a base-plate and a bridge supporting the two ends of the barrelarbor, severalpillars connecting the base-plate to the bridge and fixing them with respect to one another, a click for retaining'the ratchebwheel, and a resilient element acting upon the click.

Watch movements of this type are known to be generally of a simplified construction and are so designed as to make possible mass-production at a minimum cost price. in contrast to the socalled recessed-plate movements, both the base-plate and the bridges of pillar movements are for the most part blanked flat plates having no recesses in their thickness. The retainingclick is generally mounted on a pin fixed in the inner face of the bridge or the base-plate, and the resilient element which acts upon it is a spring wire, likewise fastened at one end to the inner face of the bridge of the base-plate.

Also known are watch movements where the retaining-click is a flat plate blanked in one piece with a resilient arm. This flat plate is fitted in a recess in the barrelbridge, is situated under the ratchet-wheel, and meshes with the crown-wheel. This design, in which it is no longer necessary to fit separately the spring acting upon the click and the click itself, would not be suitable for a movement of the type mentioned above because the barrel-bridge must have recesses and consequently involves long and costly machining operations.

Certain timers, equipped with a clockworkmovement in which the mainspring is connected to a motor which is started periodically in order to keep the movement running continuously, comprise a barrel with a drum having a toothing connected by a geartrain to the winding motor, on the one hand, and a wolf-tooth toothing cooperating with a retaining-click, on the other hand, so that the drum acts as the ratchetwheel. in an arrangement of this type, the barrel-arbor carries the first wheel which drives the gear-train of the movement. Since the barrel is mounted between two fiat plates, connected by pillars, the retaining-click pivots around a cylindrical bearing surface of one of the pillars, and the resilient element which keeps it engaged with the wolf-tooth toothing is a spring wire coiled around the aforementioned cylindrical bearing surface. This arrangement, which is suitable for timers, could not be used to advantage in a watch because of the difficulties which would be encountered in fitting the click and the coil-spring. It would not represent any simplification as compared with the arrangements used heretofore.

it is the object of the present invention to provide a simplified mechanical watch movement in which the device which prevents the ratchet-wheel from turning in the direction which allows the mainspring to unwind is composed of a minimum number of parts capable of being manufactured and assembled efficiently, and in which the aforementioned device performs its assigned functions reliably and with a minimum of friction.

To this end, there is provided according to the pres ent invention a mechanical watch movement of the type initially described, wherein the ratchet-wheel extends between the bridge and the barrel-drum, the click is a blanked flat plate having an arcuate indentation in one of its edges, the said indentation is engaged on a cylindrical bearing surface of one of the pillars at the level of the ratchet-wheel, and the said resilient element is an arm blanked in a plate integral with the frame of the movement.

Other objects and advantages of the invention will become apparent from the following detailed description of a preferred embodiment thereof, taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a top plan view of a preferred embodiment, and

FIG. 2 is a section taken on the line llll of FIG. 1.

The watch movement shown in the drawing is designed so that it can be manufactured by the fastest and most efficient possible means. To this end, all the elements of this movement have been simplified, they have been reduced in number, and their form has been so chosen as to facilitate both their manufacture and their assembly.

As will be seen in FIG. 1, the movement comprises a base-plate l, a barrel-and wheel-train bridge 2, a balance-cock 3, and between these frame elements, the members of the wheel-train, viz., a barrel 4 (FIG. 2), an eccentric center-wheel 5, a third wheel 6, a central fourth wheel 7, an escape wheel 8, a pallet 9, and an oscillating system with balance and balance-spring 10. The dial-train will be described further on.

The winding and setting mechanism comprises a sliding crown-wheel 11 which rests on the balance-cock 3, placed a little lower than the bridge 2, a stem 12 machined with a pinion toothing l3, and a setting-wheel (not shown in FIG. l) which pivots on the lower face of the base-plate l. The stem is held in place by a resilient plate 14 which partly extends under the balancecock 3 and which is fastened around a cylindrical bearing surface of one of the pillars supporting the balancecock 3.

Whereas the balance-cock is fastened on two pillars integral with the base-plate 1 by means of screws 15, the bridge 2 is fastened to the base-plate 1 by three

pillars

16a, 16b, 160 which are riveted t0 the base-plate l and to the bridge 2, as can be seen in FIG. 2. The cylindrical ends of the pillars are engages in circular openings cut out of the base-plate l and the bridge 2 and are then turned back laterally over the outer surfaces of those frame elements, thus ensuring the rigid and permanent attachment of those elements tov the frame of the movement described.

As will be seen in FIG. 1, the base-plate 1 takes the form of a square with rounded corners. it is blanked according to the outline shown in the drawing and has in one of its straight sides a positioning notch 17 serving for various machining operations. The base-plate 1 is also lathe-turned so as to have projecting edges 18 which are formed out of part of its thickness and which serve to support the movement in the watch-case or on the fitting-ring.

Holes

19 and 20 serve for the engagement and fastening of the dial-feet. It will be noted that they are situated in a region of the plate which is completely outside the central circular zone occupied by the parts of the movement and covered by bridges 2 and 3. This arrangement of the base-plate in itself makes possible a simplification of manufacture. For in order to fasten the base-plate on the lathe used to form the peripheral grooves of the edges 18, part-holder can be used which are adjusted to the distance between the parallel straight sides of the base-plate, no matter what the diameter of the rounding at the corners of the baseplate may be. These same part-holders may therefore be used for base-plates where the diameter of the rounding corresponds to calibers of various sizes. Thus, for example, the rounded corners of the base-plate 1 may be blanked and turned to dimensions corresponding to a 13" or a 12" caliber. The same wheel-trains and the same bridges will be used for both these calibers. if the diameter of the roundings of the base-plate is less than that shown in the drawing, i.e., if the roundings extend closer'to the centers of the straight sides than is the case in the drawing, then

holes

19 and 20 will be punched closer to the center.

The various punchings, blankings, and milling of the plate 1 will not be described here in detail inasmuch as these elements are for the most part conventional.

A square hole 21 in bridge 2 corresponds to two square holes in the base-plate l, and these holes serve to fasten apartial stem cock on which the crown-wheel ll pivots. A similar partial stem cock 22 is held in place between a notch in the balance-cock 3 and a rectangular hole in the base-plate lin the vicinity of the straight side turned toward 3 oclock.

As will be seen in FIG. 2, the dial-train presents a particularity which-greatly simplifies its manufacture. in this figure can be seen the pillar 16a which connects the base-plate l to the bridge 2, the central fourth wheel 7 with its spindle passing through a pipe 23 fastened to the center of the base-plate 1, and the barreldrum 4. The latter has a toothing 24 which is engaged with the pinion of the eccentric center-wheel 5. The drum 4 is further provided with a tubular central hub extending inside the drum in the form of a cylindrical bushing 25, on the'one hand, and outside the drum into the vicinity of the base-plate l in the form of a sleeve, on the other hand. The outer portion 26 of the sleeve has an annular groove 27, the bottom of which is broken through along a portion of its periphery so as to form a slot 27a. Engaged within the

hub

25, 26 is abarrel-arbor 28 fitted freely to the inside dimensions of the hub. Near its two ends, the arbor 28 passes through two

openings

29 and 30 in the bridge 2and in the base-plate 1, respectively, thus enabling the barrel 4 to pivot. At the level of the groove 27, the arbor 28 also has a groove 31 with a trapezoidal profile, in the bottom of which rests one of the arms of a bolt 32, the outer arm of which is engaged in the groove 27. This bolt 32, of a hairpin shape, forms a friction coupling between the arbor 28 and the barrel 4. At the same time, it fixes the arbor 28 axially. As the

openings

29 and 30 have the same diameter as the opening of

thehub

25, 26, the arbor 28 can thus slide axially and be removed. The bolt 32 is placed on the barrel 4 before the latter is fittedin the movement, and it resiliently presses the arbor 28 against the inner surface of the

hub

25, 26. The inner edge of its arm which is in contact with the bottom of the groove 27 has a concave rounding, while the inner edge of the other arm is straight and rests against the arbor 28 through the opening in groove 27.

At its upper end, the arbor 28 has a frustoconical head 33 provided with a slot. it can be grasped by this head and extracted from the movement, thus enabling the barrel 4 to be removed laterally for repair or overhaul.

Engaged on the bushing 25 which extends inside the drum 4 is a tubular core 34. It is provided'with a stophook 35 for the inner end of the mainspring, and a ratchet-wheel 36 is driven onto the upper end of it. Thus the ratchet-wheel 36 acts as a cover for the barrel 4 and extends immediately beneath the bridge 2. The length of the core 34 is very slightly less than that of the bushing 25 which, with the sleeve 26, determines the axial shake of the barrel assembly on arbor 28.

At its lower end, the arbor 28 has a square 37 which projects from the outer face of the base-plate 1 in a thinner portion of this frame element. The square 37 serves as a connection element between the arbor 28 and a minute-wheel mounted on the outer face of the base-plate 1. This minute-wheel is composed of a pinion 38 and a toothed disc 39. The pinion 38 is made by blanking from a circular disc with a square center hole adjusted to the dimensions of the square 37. It has a peripheral toothing which will be machined, preferably by milling, and as seen in the drawing, it has teeth truncated at approximately half of their height and limited by outer faces contained in an imaginary circular cylindrical surface/The toothed disc 39 has a center opening adjusted to the dimensions of this imaginary cylindrical surface, and it is driven onto the pinion 38. Since it is thinner than the pinion 38, it leaves a sufficient portion of the thickness of the teeth alongside it to ensure the meshing of the pinion 38 with an hour-wheel 41, as will be'seen in the drawing.

The hour-wheel 41 is itself mounted on acannonpinion 40 which pivots on the pipe 23 and meshes with the peripheral toothing of the disc 39.

This arrangement makes it possible to use a baseplate in which the differences in height between the various zones are reduced to the minimum. Thus the minute-wheel is fitted in a recess in the outer face of the base-plate. It is completely sunk into this recess through the bottom of which the arbor 28 passes, which enables the barrel to pivot in the base-plate. Since the friction coupling necessary for setting exists between the arbor 28 and the drum 4, the minutewheel is driven directly by the barrel-arbor owing to the rigid coupling composed of the square hole of the pinion 38 and the corresponding square at the end of the arbor 28. This indirect drive of the hands requires a minimum number of parts, and the arrangement described makes it easy to dismantle both the barrel and the timeindicating members.

The toothed disc 39 will be engaged with a settingwheel, likewise pivoting on the outer face of the baseplate and cooperating with the member of the setting mechanism.

In the event that the movement described is to be constructed to receive hourand minute-indicating members consisting of discs extending beneath the dial and partially appearing in an aperture, instead of the usual hands moving above the dial, the same constituent elements of the minute-wheel may be used. However the pinion 38, rather than being milled with all its teeth truncated, will have a certain number of full teeth regularly distributed around its periphery. The outside diameter of the toothing of the hour-wheel will be slightly less than in the case described above, so that only the full teeth of the minute-wheel pinion mesh with its toothing. The hour-wheel will normally be kept in a fixed position, e.g., by a jumper-spring, and will move by l/l2 of a revolution per hour, driven by one of the full teeth of the minute-wheel pinion.

In this case, the center opening of the disc 39 will be blanked with notches corresponding to the full teeth of the pinion 38 so that this disc may be driven onto the pinion. Provision might also be made to let the full teeth of the pinion 38 remain only for a portion of their thickness, the disc 39 then having a circular opening driven onto the portions of truncated teeth. This simplified minute-wheel drives the moving

parts

40 and 41 under conditions corresponding to conventional conditions. In particular, despite the fact that the teeth of the pinion 38 are truncated for about half of their height, an hour-wheel with a conventional toothing, such as wheel 41, meshes with them perfectly.

The arrangement of a click 42 for retaining the ratchet-wheel 36 can be seen in FIG. 1. The click 42 is a blanked flat plate having an indentation 43 in the form of an arc of about 220'? along one of its edges. On the edge of it opposite the indentation 43, the plate 42 has a beak 44 which is slightly inclined with respect to the radial direction determined by the center of the indentation 43 and the end of the beak 44. Two wings, 45 and 46, extend on either side of this beak 44, the wing 46 being limited by a straight edge which comes to rest against the toothing of the ratchet-wheel 36, while the wing 45 extends beyond the edge of the bridge 2.

As will be seen in FIG. 2, the pillar 16a has a first shoulder 47 which serves to position the bridge 2 with respect to the base-plate l and, starting at the edge of this shoulder 47, a cylindrical bearing surface 48 limited axially by a second shoulder 49. It is on the cylindrical bearing surface 48 that the indentation 43 of the click 42 is engaged, so that the latter is held axially in place between the inner face of the bridge 2 and the shoulder 49. The beak 44 is engaged in the toothing of the ratchet-wheel 36, and normally, the action of the mainspring presses the wing 46 against this same toothing, so that the ratchet-wheel 36 is blocked. However, if pressure is applied to the wing 45 which projects beyond the bridge 2, the beak 44 is disengaged from the toothing of the ratchet-wheel 36, which allows the mainspring to be let down.

Upon winding, when the stem 12 is turned so that the crown-wheel 11 is driven counterclockwise as viewed in FIG. 1, this wheel 11 comes to mesh with the toothing of the ratchet-wheel 36 and turns it clockwise. The click 42 pivots so that the beak 44 leaves the toothing. It is then returned by a spring consisting of an arm 50 blanked in the resilient plate 14 and resting on the end of the indentation 43 situated on the same side as the wing 46. v

A hole 51 made in the bridge 2 makes it possible to verify whether the click is in place and whether it is properly resting against the ratchet-wheel.

The arrangement of the click 42 which has just been described considerably simplifies the manufacture of the movement for several reasons. First of all, whereas the conventional clicks are generally held in place by a step-screw, the click described here pivots around a cylindrical bearing surface which is lathe-turned directly in one of the pillars of the movement. Thus the manufacture of a part is avoided, and above all, of a threaded part. Moreover, the production of a click with an indentation in the shape of an arc of more than 180 requires vastly simpler tooling than that of a click having a hole. Clicks must be made of steel in order to prevent them from wearing out too quickly, and the diameter of the pivot is obviously very small. The tools required for blanking and punching steel plates with a small-diameter hole are extremely delicate and, consequently, highly subject to breakage, as well as being very expensive. The manufacture of a blanking tool having the necessary shape for producing the click 42 is much less expensive, and this tool is much sturdier than one having a punch for cutting out a hole. The tooling costs for manufacturing the click 42, as well as the rejects, are therefore considerably reduced with the arrangement shown in the drawing. Finally, it will be noted that the movement described does not necessitate the manufacture and fitting of a special spring for the click since this spring is blanked in one piece with the one which holds the winding-stem in place. This plate, made of beryllium bronze, for example, performs two functions, and it, too, is very simple to fit in place.

What is claimed is:

1. A mechanical watch movement comprising a mainspring fitted in a barrel-drum rotating around a barrel-arbor, an inner member to which the mainspring is hooked, a ratchet-wheel integral in rotation with the inner member, a base-plate and a bridge supporting the two ends of the barrel-arbor, several pillars connecting the base-plate to the bridge and fixing them with respect to one another, a click for retaining the ratchetwheel, and a resilient element acting upon the click, wherein the ratchet-wheel extends between the bridge and the barrel-drum, the click is a blanked flat plate having an arcuate indentation in one of its edges, the said indentation is engaged on a cylindrical bearing surface of one of the pillars at the level of the ratchetwheel, and the said resilient element is an arm blanked in a plate integral with the frame of the movement.

2. A watch movement in accordance with claim 1, wherein the said plate integral with the frame of the movement is fastened to a second pillar and extends beneath a second bridge, the said second bridge being fastened at the end of the said second pillar at a distance from the base-plate greater than that between the first bridge and the base-plate.

3. A watch movement in accordance with claim 1, wherein the said indentation is in the shape of an arc of more than 4. A watch movement in accordance with claim 1, wherein the said one of the pillars comprises a shoulder which, together with the bridge, determines the axial position of the said click, the said shoulder being adjacent to the said cylindrical bearing surface on which the said indentation is engaged.

5. A watch movement in accordance with claim 1, wherein the said click comprises a beak on the edge of it facing the ratchet-wheel, and two wings, one wing on one side of the beak resting against the toothing of the ratchet-wheel, and the other wing on the other side of the beak extending beyond the edge of the bridge so as to allow the mainspring to be let down.

6. A watch movement in accordance with claim 5, wherein the said beak extends in a substantially radial direction with respect to the center of the said indentation.

7. A watch movement in accordance with claim 1, wherein the said resilient element rests on one of the ends of the indentation.

8. A watch movement in accordance with claim 7, wherein the said resilient element is integral with a resilient plate holding the winding-stem.

Claims

1. A mechanical watch movement comprising a mainspring fitted in a barrel-drum rotating around a barrel-arbor, an inner member to which the mainspring is hooked, a ratchet-wheel integral in rotation with the inner member, a base-plate and a bridge supporting the two ends of the barrel-arbor, several pillars connecting the base-plate to the bridge and fixing them with respect to one another, a click for retaining the ratchet-wheel, and a resilient element acting upon the click, wherein the ratchet-wheel extends between the bridge and the barrel-drum, the click is a blanked flat plate having an arcuate indentation in one of its edges, the said indentation is engaged on a cylindrical bearing surface of one of the pillars at the level of the ratchet-wheel, and the said resilient element is an arm blanked in a plate integral with the frame of the movement.

3. A watch movement in accordance with claim 1, wherein the said indentation is in the shape of an arc of more than 180*.

4. A watch movement in accordance with claim 1, wherein the said one of the pillars comprises a shoulder which, together with the bridge, determines the axial position of the said click, the said shoulder being adjacent to the said cylindrical bearing surface on which the said indentation is engaged.