US2263413A - Interchangeable balance staff for watches - Google Patents

Description

1941- J. H. BECKMANN INTERCHANGEABLE BALANCE STAFF FOP. WATCHES Filed Feb. 15, 1940 INVENTOR 14cm! fihzukcmm gw-W ATTORNEY cm. H

Patented Nov. 18, 1941 UNITED STATES PATENT OFFICE INTERCHANGEABLE BALANCE STAFF FOR WATCHES Jacob Hazai Beckmann, New York, N. Y. Application February 15, 1940, Serial No. 319,005

1 Claim.

This invention relates to new and useful im provements in a balance staff for watches.

Heretofore balance wheels of watches were constructed with staffs which are a drive fit. and which were hard to remove when it was necessary to repair the movement of the watch. After the repair work was completed and it was again desired to place the balance wheel on the balance staff, it was necessary to hammer upon the staff in order to fixedly attach the wheel thereto. After the watch had been repaired a number of times the hammering pounded down and compressed portions of the wheel body resulting in a loose fit between these parts which permitted the wheel to slide on the staff.

More specifically, this invention proposes the construction of a slide fit for the staff of balance wheels which may be repaired any number of times without destroying the operative value of these parts.

Still further the invention proposes the use of a staff having a cylindrical support portion which may be engaged into the axial opening of a balance wheel and also having a head portion engaging against a portion of said wheel body, and staff elements extending axially from the opposite ends of said portions for rotatively supporting the staff within the watch body.

As another object of this invention it is proposed to construct a novel type of spring hub cap which may be threadedly engaged on the staff element on the opposite side to the head portion of said staff and clamping this cap against the wheel to fixedly engage the balance wheel on the staff body, so as not to interfere with the fittings and positioning of the usual hair spring of the watch.

As another object of the invention it is proposed to construct the cylindrical support portion and the head portion of the staff of separate sections and applying a means thereto for holding the separate sections in different relative positions to compensate for the compressed wall areas which will be formed on the balance wheel body as the result of repairing.

Still further the invention proposes the use of opposed overhanging flanges formed on the separate sections of the cylindrical support portion and the head portion which may have shims engaged therebetween to separate these sections and compensate for the compressed wall areas.

For further comprehension of the invention, and of the objects and advantages thereof, reference will be had to the following description and accompanying drawing, and to the appended claim in which the various novel features of the invention are more particularly set forth.

In the accompanying drawing forming a material part of this disclosure:

Fig. 1 is a plan view of a balance wheel having a staff, constructed according to this invention.

Fig. 2 is an enlarged sectional view taken on the line 2-4 of Fig. 1.

Fig. 3 is a cross section of the hub cap per se.

Fig. 4 is an enlarged detailed view of a portion of Fig. 2.

Fig. 5 is a view similar to Fig. 4 but illustrating a modification of the invention.

Fig. 6 is a plan view of Fig. 5.

Fig.7 is another view similar to Fig. 4 but illustrating a still further modification of the invention.

Fig. 8 is a view similar to Fig. 4 but illustrating another modification of the invention,

Fig. 9 is a perspective view of the tool which is to be used for engaging the spring hub cap on the staff.

The balance staff for watches, according to this invention, comprises a balance wheel body l0 having an axial opening II for a staff l2. This staff I! has a cylindrical support portion l2 engaging into the axial opening H and a head portion [2 engaging against a portion of said wheel body on one end of said opening. Trunnion elements l2 extend axially from the opposite ends of the support portion l2 and the head portion l2 A hub cap I3 is threadedly engaged on the trunnion element l2 which is opposite the head portion l2 and may be clamped against a portion of said wheel body ID for releasably holding the wheel l0 fixed upon the staff [2.

The balance wheel body l0 consists of a rim portion Ill having a plurality of openings Ill into which balance pins I4 are threadedly engaged to make the wheel operate properly on the staff I2. Spokes Ill radiate from the inside wall of the rim Ill and converge on a common center which is provided with said axial opening II. The staff I2 is constructed of steel, while the balance wheel is constructed of brass which is a softer material then steel. For this reason the cylindrical support portion I2 of the staff l2 engages into the axial opening I! to support the walls of this opening to prevent them from being pressed out of shape when the hub cap I3 is clamped thereon to fixedly attach the balance Wheel Hi to the staff l2.

The hub cap l3 engages into an enlarged recessed portion ll of the axial opening II and has its bottom edge engaged against the shoulder portions ll formed by this enlarged recess for fixedly clamping the spokes l between the bottom edge of the hub cap l3 and the top edge of the head portion IZ This hub cap has a threaded opening I3 which cooperates with complementary threads l2 formed on the trunnion elements l2 for clamping the balance wheel upon the staff. The flange l3 of hub cap I3 is further provided with radial slots I3 into which a specially constructed tool I5 may be engaged for turning the cap 13 on and off the threaded trunnion element l2. This specially constructed tool l5 comprises a strip of material l5 having beveled portions l5 formed onone of its ends which may be engaged into the slots 13 formed in the hub cap l3. The hub. cap has a domeshaped portion and therefore the .end of .the strip of material l5 which is provided with the bev- II to compensate for the compressed wall portions.

This adjustment may be formed by engaging shims l1 between the opposed overhanging flanges l2 and l2 of the cylindrical support portion I2 and the head portion l2" respectively. When these shims are engaged between the opposed flanges it increases the space be tween these flanges causing the cylindrical support portion l2 to be slightly withdrawn from I the axial opening II to keep it out of contact eled edge also has a dome-shaped cutout iii.

intermediate of the edges of the strip of material which conforms with the dome onthe hub cap permitting it to be engaged over the top of this cap and into the slots 13' for turning the cap.

The tool If: is provided with a handle portion 15 in which a rotary stem [5' is held. This stem is formed with a head portion I5 at one end for rotating the flat portion 15 at the other end of stem iii. A hairspring I6 is adapted to have one of its ends securely attached in any desired way to the hub cap 13 for fixedly attaching it to the staff I2. This hair spring I8 is of a construction which is generally used in connection with balance wheels of this type and neither spring nor its manner of attachment forms any part of this invention.

In Figs. 5 and 6, the flange 13 of the hub cap !3 is fully embedded into a recess Ill formed at the mid-portion of spoke l0 by bending the spoke downwardly into a U-shape l0.

I3 is flush with the top surface H) of the spoke "1, so as to permit the hair spring 16 to be connected close to the spoke surface Ill".

According to the modification of the invention shown in Fig. '7 a means is provided for holding In this form of the invention the top surface of flange wall areas and repair clamping action of the hub cap.

This means comprises a staff 12 having a cylindrical supportportion l2 integrally formed therewith and adapted toengage into an axial opening ll formed in the spokes l0 of a balance Wheel Hi. This cylindrical support portion has an outward extending flange li on its bottom edge which engages the inner face of a separate head portion l2" which is formed with an inwardly directed flange lZ which engages the.

outer face of the cylindrical support portion l2 and against the bottom face of-the spoke HI in the vicinity of the axial opening II. A hub cap 13 is provided with a threaded opening I3 which may be threadedly engaged upon the trunnion element l2 which is opposite the head portion l2" for clamping the balance wheel on the head portion l2".

Whenit is seen that a portion of the spokes I0 in the vicinity of the axial opening I l is becoming compressed from the clamping action of the hub cap [3 permitting the adjacent faces of the hub cap and the cylindrical support portion to with the hub cap l3 to permit this hub cap to properly clamp the balance wheel l0 upon the head portion l2" of the staff 12'. In other respects this "form of the invention is the same as that shown in the previous figures, and corresponding parts may be recognized by the same reference numerals.

Furthermore, a staff constructed in accordance with this latter modification of the invention may be used in connection with a balance wheel l0, having spokes IB of any desired thickness. If the spokes are constructed of relatively thick material, fewer shims I! will be needed to keep the cylindrical support portion l2 from contacting thefhub cap 13. On the other hand, if the spokes I 0 are of thinner material, it will be required that more shims ll be engaged between the flanges IZ? and I2, for withdrawing the greater portion of the cylindrical portion l2 from the axial opening I I, and so keep this cylindrical support portion i2 from contacting the hub cap 13.

In Fig. 8, the hub cap 23 is made integral; with spoke 20 and staff 22 is screwed into the threaded opening 23 of thejhub cap. The head portion 22 of the staff is provided with radial slots 2| for screwing the staff into the'thread-ed hub cap.

a It is to be understood that this-device may be made in various sizes to accommodate different sizes of watches, also that the arrangement may be fitted on present old watches or on any new manufactured watch.

While I have illustrated and described the preferred embodiments of my invention, it is to be understood that I do not limit myself to theme-- cise constructions herein disclosed andthe right is reserved to all changes and modifications coming' within the scope of the invention as defined in the appended claim. I I

Having thus described my invention,wh'at I claim as new, and desire "to secure by United States Letters'Patent 'is: v

In awatch balance staff having a balance wheel body with an axial opening therethrough, a staff extending through said opening, said staff having an outwardly extendingflange on one side of said wheel body, a hub cap on the other side of said wheel body engaging said other side of said body, 'a-sleeve member encircling said outwardly extending flange and having an inwardly extending flange engaged between said outwardly directed flange and said one side of said wheel body, and shims mounted between said flanges and within said sleeve member.

' JACOB HAZAI BECKMANN.

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