US3474619A - Watch dial having time signs welded thereto - Google Patents

Description

Oct. 28, 1969 A. voe'r 3,474,619

WATCH DIAL HAVING TIME SIGNS WELDED THERETO Filed May 11, 1966 FIG 2 6 4 Mil-III! 40 3 Al?" ,l 35 I I 37 1Q\\\ I l6 k8 V I! I5 United States Patent Int. Cl. G04b 19/14 US. Cl. 58127 5 Claims ABSTRACT OF THE DISCLOSURE A dial for a small watch having a dial plate with a prefinished front with time signs permanently fixed thereon without alteration of the prefinished front. The time signs are each recurred by a contact area between the prefinished front and each time sign and which is spaced inwardly from the visible periphery of the respective time sign. The contact area comprises a weld surface at which a weld, defining a fusion area, secures the individual time sign without deposition of weld material. The individual time signs each have a planar cross-section area greater than the contact and fusion areas disposed overlying the individual time signs welds so that the welds and any heatdiscolored areas adjacent thereof are not visible around the periphery of the individual time signs.

This is a continuation-in-part of my application Ser. No. 328,977 filed Dec. 9, 1963 now abandoned, itself a continuation-in-part of application No. 789,913 filed Jan. 29, 1959 now Patent No. 3,197,846.

This invention is concerned with a welding process for securing time signs onto small finished dials and to watch dials having time signs welded on the finished surface thereof.

As used herein, the term finished is intended to refer to a watch dial surface which has been subjected to conventional finishing treatment including for example, at least some of the operations of dulling, polishing, dyeing, oxidizing, lacquering and electroplating and only lacks thereon the securing of time signs. When welding is completed the watch dial is in a completely finished state.

For all better quality watches, the watchmaking industry produces dials with signs secured to finished surfaces. The only method used for so doing until now which lends to the desired aesthetic appearance of the assembly, is riveting. Undesirably, this method is slow and expensive. Other methods such as glueing have been tried without acceptable results in adherence.

Welding signs onto finished surfaces has never seriously been tried. In fact, experts in the watch-making field concluded that the welding of time signs to finished dials was not feasible. Their conclusions was based on the following considerations: Because of the smallness of the sign, and the fragility of the coating (silver plating) on the watch dial, the assembly would not bear up on the Welding heat. The adherence of the time signs would be insutficient and they would fall off if the welding temperature was kept low enough so as not to mar the appearance of the finish. The insulating lacquer enamel normally used to cover the dial would prevent welding current from passing therethrough, and finally, that in the event the welds were successful, there would be formed small burrs of weld metal at the base of the symbols, which would mar the appearance of the finished dial.

3,474,619 Patented Oct. 28, 1969 The main object of the invention is to provide finished quality watch dials having time signs welded thereon.

An equally important object of the invention is to provide a method for welding time signs to finished watch dials without altering the finishing appearance of the dial and wherein the welding positions and conditions are so selected that when the finished dial is viewed the welding spots are totally hidden by the time signs.

These and other objects of the invention will be better appreciated from the following detailed description and annexed drawings, in which:

FIG. 1 is a fragmentary side elevation view of a time sign and a dial in section prior to welding by the claimed method;

FIG. 2 is an elevation view of the arrangement in FIG. 1 after welding;

FIG. 3 is a side elevation view of the arrangement in FIG. 2 illustrating the bevel edging of the symbols already permanently welded on the dial;

FIG. 4 is a fragmentary side view of another embodiment of an arrangement for carrying out the process according to the invention;

FIGS. 5 and 6 are side elevation views partly in section of other variants of the welding process according to the invention;

FIG. 7 is a fragmentary side elevation view illustrating the application of the process of the invention to dials provided with a protective varnish.

Process-wise, the present invention consists in providing a dial having a finished major surface corresponding to the face of the dial, placing in contact with the finished surface at least one time sign and welding the sign to the area of the finished surface covered by the sign by applying Welding energy while maintaining said substantially finished state of all exposed portions of the major surface of the dial. In an advantageous embodiment of the invention, the time sign is so dimensioned that it makes contact with the finished dial surface over an area spaced inwardly from the boundaries of the planar area of the sign and less than the planar area of the sign.

In the drawing a first embodiment of the process according to the invention is illustrated in FIG. 1 in which a dial 1 is fragmentarily shown in section and is illustrated as having a major surface constituting a finished face 2. A time sign is illustrated in position for welding on the face 2 of the dial 1. The sign comprises a main body portion 3 which is the part that is the indicium in a finished state. The sign has an upper portion 4 for receiving thereon a welding electrode 5 for applying welding current as later explained. Portion 4 does not necessarily extend outwardly from the main body portion 3 and is removed mechanically from the main body portion after the symbol is welded in place.

The main body portion 3 has an integral frustro-conical or pyramid-like projection 6 on the underside of the symbol. The projection is an inverted, truncated cone or pyramid having its base integral with the body portion 3 and is provided with a flat or rounded apex received in a recess 8 formed on the face 2 of the dial 1. The transverse dimension of the recess 8 is greater than the transverse dimensions of that part of the projection received in the recess. Moreover, the depth of the recess 8 is less than the height of the projection, so that when welding current is applied the symbol touches the dial only at the bottom of the recess. This is the only place where welding takes place. The welding electrode 5 is brought into contact with the portion 4, which is later removed, and another electrode engages the rear side of the dial 1. Pressure is applied by the two electrodes in the direction of the arrows 10, 11, respectively. The welding pressure, welding current, and welding time are chosen in such a way that the projection is not compressed too early. Moreover, the entire welding current flows through the projection since the symbol makes contact with the dial only on the contacting surfaces at the bottom of the recess 8. Consequently, the welding contact zone is smaller than the area to which the welding energy is applied.

Signs for dials of small watches normally have a height of between 0.25 and 0.40 mm. Very small miniature time signs are thinner than 0.25 mm. whereas the so-called super and giant signs have heights in the order of 0.66 mm. and of over 0.70 mm., respectively. In practice the dimensions of the projections on the signs as well as the welding parameters can be adapted one to the other in a wide range of variants. The following is a typical, though by no means limiting combination of data for the welding of time signs to a standard dial for small watches:

Height of projections:approximately 0.1 mm.

Shape of projectionszcircular cone or 4-sided pyramid with the base adjacent the sign and having a rounded off or flattened apex.

Surface of projection at base:approximate1y 5-10 mm.*.

Welding pressure generating the contact force per projectionzapproximately 1.5 kg.

Welding current per projectionzapproximately 1,000- amps.

Welding timerapproximately 0.8 millisecond.

With these parameters which are set forth merely by way of an example, it is possible to heat locally, practically, only, the points of contact between the projections of the signs and the surface of the dial, for a very short period such that the projection is brought to the melting point without the welding heat being able to spread noticeably around the welding spot onto the dial surface so that the dial face surface in the immediate vicinity of the weld spot on the dial is not changed visibly by the heat.

In the embodiments of the invention where signs having projections to limit the weld area to an area less than the area of the face of the dial which the sign overlies, the number of the projections on each sign depends on how securely the symbols are to be fixed on the dial. One projection is sufficient, but it is preferable to have three or even four projections, on each symbol. The projections may vary in cross-section from to 5 mm. and in height from 10- to 1 mm. depending on the size and the material of the signs. The welding time is in the range of 10- to 10- seconds. When the welding current is applied between the electrodes from a controlled source, and the electrode welding pressure or means, not shown, is set to obtain the desired pressure between the surface to be welded the projection 6 will partially melt and the height of the sign relative to the surface 2 decreases.

FIGURE 2 illustrates schematically how the symbol 3 has been lowered relative to the surface 2 as a result of the welding and is secured in the dial recess 8. The weld material 9, which has melted during welding, has fused with the base metal and any excess weld metal deposits itself in the space remaining in the recess. It is therefore not visible on the finished dial since the portion 3 has a greater transverse dimension than the recess. Moreover, the weld material does not have to be removed thereby eliminating a difficult operation necessary to gluing processes when there is excessive glue. The ground surface of the sign 3 may, of course, touch the dial 1 on the edges around the recess even in its finished state. After welding the portion 4 is removed mechanically, and the sign 3 may be mechanically beveled on the upper side as shown in FIGURE 3.

Those skilled in the art will understand that the dial 1 has a plurality of spaced recesses for receiving all of the signs that are to be fixed by welding on the face 2 of the completed dial. The sign may be welded individually or jointly by properly constructed apparatus not shown.

In carrying out the process of the invention the recess need not be provided in the dial but may be provided in the sign. Thus as illustrated in FIGURE 4 an hour sign 14 is illustrated in position for welding on a dial 15 illustrated diagrammatically. The sign has a recess 16 on the underside thereof for receiving a projection 17 on the face surface of the dial. The recess 16 has less depth than the height of the projection 17 so that the sign 14 is held spaced upwardly from the face 18 of the dial.

The recess and the projection are relatively dimensioned so that in this case the recess has greater transverse dimensions or area than the transverse dimensions or area of the projection 17. The sign 14 may have its surfaces bounding the recess beveled as illustrated to provide a space between the sign and the projection for receiving weld metal therein. The sign 14 is welded by applying welded current from two electrodes, not shown, in a manner similar to FIGURE 1. The electrodes are, of course, aligned on opposite sides of the dial and positioned in alignment with the recess 16 and the dial projection 17. When a proper welding current and welding pressure are applied to the contacting surfaces of the sign 14 and the projection 17 the two are welded by a strong bond of weld metal 20.

It can be seen in FIGURE 4 that the sign 14 extends outwardly from the projection 17 and overlies a greater area on the dial surface or face 18 surrounding the projection 17 so that any discoloration that might result from the welding cannot be seen since the sign overlies and covers it. Moreover, weld splatter cannot show on the face of the dial surrounding the sign and which can be seen on the completed dial. Similarly to the illustrations of the invention in FIGURE 1 the completed dial 15 will have a plurality of time signs properly spaced. Thus the dial 15 has a plurality of projections, not shown, formed thereon properly spaced in positions corresponding to the positions on which the signs are to be mounted in the manner in which the recesses in the illustrations in FIGURE 1 are properly disposed in positions in which symbols are to be secured.

In the illustrations of the process of the invention above-described it is possible to eliminate the recesses 8, 16 in which case the height of the time signs will be somewhat higher. Thus instead of using salient projections either on the signs or the dial cooperative with the bottom surface of a recess it is possible to carry out the method of the invention by making sure that the contacting surfaces, and thus the weld area, are sufficient to carry out a strong weld and yet be sufficiently smaller than the planar area of the symbol so that the signs completely covers the weld area and it cannot be seen when viewing the dial face of a completed dial. Illustrations as to how to manufacture dials with these embodiments of the method of the invention are illustrated in FIGURES 5, 6 and 7 and will be described hereinafter.

The method heretofore described comprises the use of a welding electrode applied directly to a body portion 4 of the sign so that if there is any marring of the body portion, the sign in a finished state will not be marred since the body portion 4 is removed. It is possible, however, to manufacture watch dials according to the invention by first producing finished signs and finished dials. The finished signs are then welded on the finished surfaces of the dial face by applying one or more electrodes directly onto the finished surface of the sign. The process according to the invention in this case provides for avoiding any marring of the sign by the electrode or discoloration by welding current by providing an electrode made of a suitable soft material which is also a good conductor and does not tend to adhere to the surface of the sign. Such an electrode or electrodes will make only relatively insignificant marks on the sign surface and these can be easily removed by polishing after the welding operation.

In order to achieve uniform and gradual current flow through the sign to avoid excessive localized heating, which can result when a large surface electrode is applied to a sign in view of its uneven contact with the sign surfaces, the process of the invention can make use of several electrodes as illustrated in FIGURE 5. According to FIG- URE 5 a sign 23 made of an electrically conductive material is provided with two spaced projections 24, 25 of the type heretofore described, disposed in contact with a face surface 27 of a dial 28 on which it is to be welded. As illustrated, a plurality of electrodes 30, for example three electrodes, are applied directly to an upper, finished surface 31 of the sign 23. It being understood that an electrode, not shown, is applied to the underside of the dial 28 in the manner heretofore described.

By using a plurality of electrodes only a fraction of the total welding current flowing through the sign 23 flows through each electrode. For example, in FIGURE 5 each of the electrodes 30 carries one-third of the total welding current so that the current density distribution is more gradual and uniform throughout the dial thereby precluding any marring or discoloration of the sign during the application of the welding current. The electrodes 30 are constructed of a suitable soft material, for example silver graphite which is a good conductor and will not tend to adhere to the upper surface 31 of the sign 23 and any minor marking of the surface of the sign during welding can be readily removed by polishing subsequent to the welding operation.

The process according to the invention also can be carried out by constructing a time sign, as illustrated in FIGURE 6 in which a sign 35 is provided with a rounded surface 36 so that the sign makes intimate contact for welding with the face surface 37 of a dial 38 along an area which is less than the planar area of the sign 35. In order to protect the sign from damage a holder 40, having an underside recess 41 for receiving the sign 35 therein, is placed over the sign and the welding electrodes, not shown, applies pressure and current directly to the top surface of the holder and the underside of the dial 38. As the welding energy is applied the sign 35 melts along the contact surface. The rounded portion of the sign thus melts in the area of contact, however, the welding is controlled such that the welding metal does not flow over an area as large as the planar area of the electrode 35 so that the weld remains invisible. Thus it is possible to weld the signs directly onto the major face surface of the dial since in the illustrations of the invention in FIGURES 5 and 6 and neither the dial or the dial need be recessed as heretofore described.

Another variant of the invention is illustrated in FIG URE 7, in which is shown a dial 45 on which a finish electroplating coat 46 has been applied. The dial 45 has a protective coating or veneer 47 as heretofore described applied over the electroplating to protect the watch during its life and during handling thereof. In this case, a sign 49 is to be welded, according to the invention, directly onto the finished face surface. The sign 49 is provided with two projections 50, 51 constructed as heretofore illustrated in the other embodiments of signs having projections of this type with the exception that the apex of each of the projections 50, 51 is sharper than in the other illustrations so that the projections can pierce the protective coat 47 and make contact with the electroplating 46 which is electrically conductive.

The sign 49 can be, for example, welded in the manner illustrated in FIGURE 5 or in FIGURE 6 by the application of electrodes directly or by use of a protective holder. Since the sign 49 is completely finished, the use of a plurality of electrodes, as illustrated in FIGURE 5, will provide for manufacturing a watch dial of finished component parts, such as the dial plate and the signs, in which any marring of the signs can be readily removed by polishing and moreover the use of a holder of the type illustrated in FIGURE 6 provides for the manufacture of a finished watch dial from completely finished signs and dial plates.

In the event that any further finishing is to be done, for example, as illustrated with respect to the sign in FIGURE 1, the mechanical removal of a portion of the sign requires that the sign be well secured to the dial.

In the various descriptions of the application of the process according to the invention, the signs and the dials are electrically conductive. However, the invention can be applied to dials that are not electrically conductive. For example, the dials can be made of a plastic material in which are embedded in proper positions electrically conductive elements on which the welding of indica is to take place. Thus, electrically conductive portions are built into the dial. It being understood, that these electrically conductive portions extend completely through the thickness of the dial, not shown, in which case the invention is practiced on such dials in the manner heretofore described.

Moreover, although the welding of signs according to the invention is illustrated with respect to the welding of hour signs or hour indicia on the dial. Those skilled in the art will understand the invention is equally applicable to the welding of other indicia, such as the name of a manufacturer on the dial face in which the elements are welded under controlled pressure, currents and welding time properly set as heretofore described with respect to each of the illustrations of the application of the invention.

The invention can be practiced by manually positioning and welding the signs in their proper spaced positions. However, the invention is best practiced by providing for mass production of watch dials, for example, by the use of automatic and semi-automatic means not illustrated. Thus, is is known in the art to construct holding tools so that all of the signs are held within the tool in properly spaced positions relative to a dial, which may be also received into the tool so that all of the signs can be welded simultaneously or sequentially as desired. Furthermore, the signs can be constructed jointly by stamping, punching or electro-deposition methods with all of the signs held on a common carrier from which they have been constructed and this carrier is applied to the watch dial as illustrated in the aforementioned Patent No. 3,197,846, so that the signs can all be resistance welded and then the remaining part of the holder mechanically removed, so that only the signs remain on the dial. By use of such a carrier, for example, the time signs can all be welded jointly and then the name of the manufacturer can be welded thereon separately.

According to the invention the manufacture of high quality dials is simplified so that the cost of dial production is about one-half of the riveting process. Moreover, watch dials made according to the invention have an equivalent high quality appearance and the indicia is as adequately secured as in the riveting process.

Those skilled in the art will recognize that the welding energy can be other than an electrical current. For example, supersonic vibratory energy may be used in order to secure the signs. Instead of the use of an electrode, a supersonic vibratory head may be connected to the signs and vibrate them in known manner so that the invention can be applied to completely finished dial surfaces with the use of this kind of welding energy. For this variant of the invention, it is preferred to use an arrangement such as that shown in FIGURE 6 wherein 35 is the curved time sign and 40 in this case, would represent the vibratory head. Generally, the curved surface of the sign should not be as exaggerated as shown in the drawing. Indeed, as a matter of manufacturing convenience, it has been found suitable to simply tumble together a large number of signs in a tumbling mill. This produces a rounding of all the sharp edges of the signs which in the case of the upper sides of the sign, i.e. those enclosed by the vibratory head can be sharpened again by polishing.

What is claimed is: 1

1. A dial for a small watch comprising, a dial plate having a prefinished front, at least one timesign positioned on said dial plate permanently fixed to said dial plate front and having a visible outer periphery, means comprising a projection extending between the time sign and the prefinished front of said dial defining a contact area between said prefinished front and said time sign spaced inwardly from said visible outer periphery of said time sign, said contact area comprising a weld surface for fixing the time sign to the prefinished front of the dial plate, a weld at said weld surface securing said time sign to said dial plate prefinished front without deposition of weld material other than that initially in said dial plate and said time sign and defining a fusion area corresponding substantially with said contact area, said time sign having a planar cross section area greater than said contact area and overlying said weld completely covering said weld and any heat-discolored area of said prefinished front adjacent to said weld, and the prefinished front of said dial plate visible around said outer periphery of said time sign being unaltered by said weld and said heat-discolored area.

2. A dial for a small watch according to claim 1, in which said projection is integral with said time sign.

3. A dial for a small watch according to claim 2, in which said dial plate front has a recess receiving an end of said projection, said projection having a transverse dimension less than the transverse dimension of said recess, and said weld being disposed and contained within said recess.

4. A dial for a small watch according to claim 1, in which said projection is integral with said dial plate front and extends outwardly therefrom, said time sign having a recess receiving an end of said projection, and said weld being disposed within said recess.

5. A dial for a small watch according to claim 1, in which said weld surface is convex.

References Cited UNITED STATES PATENTS 2,188,872 *1/1940 Carlson 58l26 2,566,741 9/1951 Newhouse 58-127 2,606,418 8/ 1952 Fliickiger 58127 FOREIGN PATENTS 1,140,179 2/ 1957 France.

893,410 10/1953 Germany.

188,927 5/ 1937 Switzerland.

248,536 5/ 1947 Switzerland.

RICHARD B. WILKINSON, Primary Examiner STANLEY A. WAL, Assistant Examiner

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