US2205407A

US2205407A - Watchcase construction

Info

Publication number: US2205407A
Application number: US90941A
Authority: US
Inventors: Hoffer Leopold
Original assignee: Individual
Current assignee: Individual
Priority date: 1936-07-16
Filing date: 1936-07-16
Publication date: 1940-06-25
Anticipated expiration: 1957-06-25

Description

June 25, 1940. L HQFFER 2,205,407

WATCHCASE CONSTRUCTION Filed July 16, 1936 INVENTOR.

% 2M3, ATTORNEYS Patented June 25, 1940 UNITED STATES PATENT orr ca ws'rcnoasnoonsmuc'non Leopold Hofier, Cincinnati, Ohio Application July 16,1936, SBHBIINO. 90,941

6 Claims. (01. 58-90) My invention relates to watchcases and more especially to watchcases of the simpler and smaller types, notably wrist watches, in which, as heretofore manufactured, the support for the winding and setting stem of the watch movement, in the watch case, has been inadequately provided for, and in which usually the closure therearound has been insufiiciently provided against entrance of foreign matter to the watch movement.

The type of watchcases to which my invention is more especially directed usually are simply drawn up and formed of sheet metal, and for admitting the movement stem there is left simply an opening amply large without any attention to forming this opening in such a manner as to accurately receive the stem whereby it could afford an adequate bearing and an adequate closure around the stem. In many instances the shape of this opening is merely that which results from forming an opening in the blank and allowing this opening to change its form incident to the forming operation on the blank, so that the opening is very irregular in shape and must be provided so as to be amply larger than the stem on account of this irregularity of shape.

In instances where the opening receives the stem closely the extent of the bearing may be only that of the thickness of the sheet metal, which becomes worn away so that there is no longer a bearing or support for the stern, nor sufiicient closure to exclude foreign substances from the case.

In any of these situations, with the stem not having a bearing in the watchcase in addition to its bearing in the watch movement, of which it forms part, the stem, in its extension from the watch movement out through the case, is liable to considerable deflection under the pressure of winding operation, so that not only does the watch seem to be fl msily constructed, but there is actually an undesirable tendency for the stem to wear in its hearings in the watch movement,

and the lack of the support of the stem increases the possibility of bending and breaking the stem.

To leave a considerable opening for the entrance of dirt, dust, and moisture, including perspiration of the wearer, of course greatly increases the depreciation of the watch movement from clogging, excessive wear, rust and corrosion of the movement parts, in addition to the damaging tendencies due to the lack of proper support of the stem above pointed out.

Furthermore in a large proportion of watch- I cases of the type with which my invention is especially concerned, not only is the stem not properly supported but the crown is spaced out away from the exterior of the watchcase, either very noticeably, or at least to that extent that is necessary on account of there having been no attention given to forming the exterior of the case to an accurate bearing of the crown against it. The result of this is that the crown, as regards to its connection to the stem, is subject to considerable tilting strain in the operation of 10 winding and therefore is liable to be bent out of proper position on the stem, or may even be, in time, broken from the stem.

It is the object of my invention to provide against the above defects found with the usual 5 watchcases, so as to provide the stem with an adequate bearing, to provide adequate closure around the stem, and also preferably to adequately support the crown, so that the stem and crown will be supported against the strains of winding operations and so that durable bearing will be afforded in the watchcase for the stem.

My improved construction, though not limited thereto, is especially adapted for provision, by watch repairmen, in cases already constructed, of a support member which is made especially to fit the particular watchcase, in the manner hereinafter to be described.

Further objects will appear in the course of the following description, illustrated by the accompanying drawing, in which Fig. 1 is a front elevation of a three-piece wrist watchcase to which my invention is applied;

Fig. 2 is an enlarged edge elevation of the same, partly in section on the line 2-2 of Fig. 1;

r Fig. 3 is a detail perspective view of the support member involved in my improved construcron; v v V Fig. 4 is aperspective view of a three-piece watchcase of modified shape but of thesame con- 40 struction as that of Figs. 1 and2- so far as my invention: is concerned, the support member being shown above the watchcase, and the watchcase being only partially assembled or closed; and I Fig. 5, in a similar manner, illustrates a similar watchcasabut of two-piece construction, il ,lustrating how my invention is embodied therein.

. H or H and the bezel 12 or [2' carrying the

crystal

13 or 13.

As is well known in the art, such a watchcase as illustrated is constructed for that mode of assembly. It will be under- 55 stood, however, that these details, and any other details of assembly of watchcaseipieces, or of their shape, do not materially afiect my invention.

The part of the case with which my invention is intimately concerned is the stem opening It in the center Iii or Id.

In Fig. 2 a watch movement I5 is shown mounted in the center iii by means of case screws it in the usual manner. The winding and setting stem. ill, usually considered as part of the movement it, is received in and supported by the movement I5, but it is understood, as ordinarily provided, would be readily detachable from the movement in the course of inserting or removing the movement into or from the watchcase.

As previously explained, the opening it is not usually accurately formed in the relatively thin Walls of the case center it or Iii and is formed sufficiently larger than the stem to avoid necessity of accurately forming this opening. In i1- lustrating, I have not shown the watchcase with this usual irregular opening but show it with an accurate circular opening aligned with the stem bearing in the movement it, the opening being relatively much larger than the diameter of the stem portion that passes through the opening; this size and accuracy having been provided as a part of the operation of embodying my invention in the watchcase of the usual less accurate construction.

Into this opening is accurately fitted the stem and crown support member I8, which comprises a main hollow, cylindrical body portion having, at one end only, a relatively widely projected annular flange I9. The exterior of the body portion accurately fills the opening I 4, the flange I9 closely abutting the exterior of the watchcase center ill or I 0 around the openin I4; and the cylindrical interior 20 forms the bearing for the stem while the top or outer surface of the support I8 forms a bearing for the under surface of the crown 2|, preferablybeing of such diameter as to receive the greater part of the area of this under surface; This support member I8 fits the opening Ilsufliciently tight to remain stationary in the center II] or III", and although the exterior surface 22 of the center III or I0 has only such accuracy as is given in forming this center by the usual methods of large quantity production, it will be understood that the flange I9 will fit sufilciently accurately to give the support member I8 a firm bearing, so that it maintains an accurate relation to the movement I5 and the stem I! thereof.

The flange III also adds to the distance that must be traveled by foreign substances to enter the case, thus adding to the effectiveness of the closure formed around the stem.

Many of the watch movements have the stem ll of the construction illustrated in Fig. 2 in which thereis an enlargement or hub 23 unitary with the stem I'I immediately under the crown 2| and extending a considerable distance therefrom-along the stem. This enlargement or hub serves in the ordinary construction to reinforce the connection of the stem and its crown.

In addition to the movements incident to winding, it is of course understood that there is also an axial movement of the stem to bring it into and out of position for setting the watch, and although this does not occasion nearly as much wear, it does create a condition in which lack of support leaves the stem and crown greatly exposed to the dangers of bending and breaking.

With regard to the wear in the bearing, if the usual watchcase only is allowed to form the bearing for the stem, it will be understood that the watchcase part is not only usually. too thin to form an adequate bearing as above noted but is usually made of a relatively soft metal such as go1d,.silver, platinum or the like, not adapted to form a suitable bearing, whatever its extent may happen to be. Also it should be well understood that in a great many watchcases the opening I4 is not formed for the stem to fit it at all but is left in the case as formed, in the manner previously pointed out. It is of course desirable that the support member I8 should be of material hard enough to add to the life of the bearing over that permitted by the ample area of the bearing; and it is also desirable that the member should be of material that will well resist corrosion. Accordingly, though ordinary 'steel affords the hardest bearings, it is more desirable to use a rustproof material, such as brass, bronze, German silver or any one of a large number of corrosion resisting alloys known in the art. Stainless steel may be used. It will be understood of course that I am not limited as to the mates rial used in the member I8.

In the cases of two-piec construction, as shown in Fig. 5, the back Ila receives the bezel or front I20; in telescoping relation; the back i in being formed with a shoulder 22a, all around, of the thickness of the metal of the bezel I2a. These cases usually are made with two parts Ila and I2a having notches Ma and Nb respectively which register to leave an opening for the movement stem when the case has been assembled. However, in the usual quantity production, when the case parts Na and I 2a are formed of sheet metal, these notches are allowed to have merely the irregular shape incident to drawing up the material after the notches have been formed in the blanks, with the notches amply large to avoid accurate fitting around the stem.

With watchcases of this construction, my invention is incorporated by bringing the back Ila and bezel I2a into assembled relation, and then accurately enlarging the opening formed by the notches Ila and Nb in accurate alignment with the bearing in the watch movement in the same manner as the opening in the center of the threepiece case is treated, according to the previous description. Then the support memben I8 is formed to accurately fit the opening thus provided, with its flange I9 fitting against the edge surfaces of the case'portions Ho and Ho as permitted by the shoulders 22a which brings these surfaces substantially in a single plane.

I have shown modifications in which my invention is embodied, but it will be understood that other modifications will'arise, and what I claim is:

1. In a watchcase construction, in combination with a watchcase having an opening through which extends the stem of a watch movement mounted in the case, said opening being of greater diameter than the part of the stem therein, a support and sealing member comprising a cylindrical body portion extending through and frictionally held in said opening, with a central axial passage around which its walls are continuous from end to end, forming a bearing for the stem interiorly and a sealing contact with the case-opening edge exteriorly; said member also comprising a flange at the outer end of the sup 'port member having a bearing against the exterior surface of the case around said opening,

the opposite end of said body portion being devoid of flange or other extension, permitting said support member to be inserted from the exterior of the case into said opening, said opening having such accurate concentricity with the stem that said support member, held in said opening due only to its frictional contact therein and said bearing of said flange against the case, operatively supports the stem and seals the watchcase therearound, for the purposes set forth.

2. A watchcase construction as set forth in claim 1, in which the flange is so proportioned that, when bearing against the case as therein set forth, it also has a bearing and supporting contact with the crown of the stem when the stem is in operative position in the support member and watch movement and is adjusted to movement winding position.

3. A watchcase construction as set forth in claim 1, in which the stem has a crown and has a hub or neck portion reinforcing the connection of the stem and its crown, of materially greater diameter than the movement-engaging part of the stem and operatively received in the interior passage of the support member.

4. A watchcase construction as set forth in claim 1, in which the stem has a crown and has a hub or neck portion reinforcing the connection of the stem and its crown, of materially greater diameter than the movement-engaging part of the stem and operatively received in the interior passage of the support member, and in which the flange of the support member is so proportioned that, when bearing against the case as therein set forth, it also has a bearing and supporting contact with the crown of the stem when the stem is in operative position in the support member and the watch movement and is adjusted to movement winding position.

5. A watchcase construction as set forth in claim 1, in which the case part having the opening is the center member of the case and contains the opening completely within its structure.

6. A watchcase construction as set forth in claim 1, in which the watchcase comprises telescoping sections having notches in their lapping edge portions to form the stem opening, the collective formation of said notches providing the opening to receive the support member as therein set forth, and one of said telescoping sections having a shoulder whereby the watchcase surface around said opening is substantially all in a single plane whereby the flange of the support member has its bearing against the exterior of the'case as therein set forth.

' LEOPOLD HOFFER.