U.S. patent number 3,874,162 [Application Number 05/488,366] was granted by the patent office on 1975-04-01 for solid state watch stem detent and switch assembly.
This patent grant is currently assigned to Timex Corporation. Invention is credited to Raymond Robert Boxberger, Jack Schwartzschild.
United States Patent |
3,874,162 |
Boxberger , et al. |
April 1, 1975 |
Solid state watch stem detent and switch assembly
Abstract
A solid state digital watch comprises a stem detent and switch
assembly which includes a crown portion on the outside of the watch
case and a shaft portion extending therethrough. The shaft portion
includes an intermediate rectangular section on the inside of the
case which cooperates with a single stamped spring to provide a
four position rotary detent action. In addition to permitting
detent holding of the stem in the proper contact position, this
arrangement also provides electrical contact to ground the stem to
the case. The internal end of the shaft includes an eccentric tab
which contacts one of three precisely positioned blades when the
stem is rotated to advance the minutes or hours counters, to reset
the seconds counter or to shut down the watch.
Inventors: |
Boxberger; Raymond Robert
(South Nyack, NY), Schwartzschild; Jack (Stamford, CT) |
Assignee: |
Timex Corporation (Waterbury,
CT)
|
Family
ID: |
23939455 |
Appl.
No.: |
05/488,366 |
Filed: |
July 22, 1974 |
Current U.S.
Class: |
368/156; 200/6BA;
368/190; 968/447 |
Current CPC
Class: |
G04C
3/001 (20130101) |
Current International
Class: |
G04C
3/00 (20060101); G04c 009/00 (); G04b 027/00 ();
H01h 019/00 () |
Field of
Search: |
;58/23R,23BA,34,67,85.5
;200/6BA |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Miller, Jr.; George H.
Claims
What is claimed is:
1. A stem detent and switch assembly for a solid state digital
watch with a circuit inside a case which comprises:
an elongated shaft, an eccentric tab at the interior end thereof,
an intermediate rectangular section and an end portion projecting
outwardly from the case,
a plurality of switch blades mounted for selective engagement with
the eccentric tab to provide predetermined setting functions for
the watch in cooperation with the watch circuit and,
a spring member engaging the rectangular section to provide a
detent action and having a base portion biased against the case to
provide electrical contact therewith.
2. A stem detent and switch assembly for a solid state digital
watch in accordance with claim 1 wherein :
the plurality of switch blades comprise a pair of spaced apart
cantilevered blades mounted opposite each other in the same plane
and a third cantilever blade mounted in the space between the
opposed blades and in a plane parallel to the plane of the first
two blades.
3. A stem detent and switch assembly for a solid state digital
watch in accordance with claim 1 wherein:
the diameter of the rectangular section is less than the diameter
of the shaft portion to provide a shoulder for engagement by the
spring member to bias the stem axially regardless of its rotational
position during detenting
4. A stem detent and switch assembly for a solid state digital
watch in accordance with claim 1 wherein:
the cooperating spring member comprises an elongated base portion
in biased engagement with the watch case, and, a pair of protruding
substantially U-shaped arms extending therefrom with the juxtaposed
arms being free at the ends thereof to exert radial locking
pressure on the rectangular section of the shaft which is located
therebetween and to exert axial biasing of the stem.
5. A stem detent and switch assembly for a solid state digital
watch in accordance with claim 1 wherein:
the rectangular section cooperates with the spring to provide a
four position rotary detent action.
6. A stem detent and switch assembly for a solid state digital
watch in accordance with claim 1 wherein:
the switch blades comprise thin beryllium copper stampings.
7. A stem detent and switch assembly for a solid state digital
watch in accordance with claim 1 wherein:
the end portion of the shaft projecting outwardly from the case
includes a crown mounted thereon, and,
the cantilevered switch blades are connected at one end thereof to
the solid state circuit of the watch.
Description
BACKGROUND OF THE INVENTION
The present invention relates to solid state watches and
particularly to a stem detent and switch assembly for solid state
digital watches.
One of the main problems encountered by the prior art in solid
digital watches is the provision of means to set and reset the
watch. A typical switch arrangement for accomplishing such
operations is disclosed in the pending application, Ser. No.
462,151, filed Apr. 18, 1974, by the present inventors. Preferably,
the switch arrangement would involve a single stem and a minimum of
associated parts. In a number of prior art designs, however, it has
been necessary to provide at least two stem arrangements in order
to obtain the necessary flexibility in setting the watch.
In the digital watch of U.S. Pat. No. 3,756,011 to Nishimura et al,
filed Sept. 7, 1972, the correction of each display element is
achieved through the use of a single winding crown. A square
portion of the crown is coupled to the mating aperture of a wiper
element which engages one of a plurality of fixed contacts in order
to set and reset the watch. The end portion of the crown also
comprises a switch which opens or closes the circuit when the crown
is moved axially.
In further prior art references, U.S. Pat. No. 3,733,803 to Hiraga,
et al, issued May 22, 1973, discloses a rotary switch which permits
adjustment in the time of an electronic watch and which includes a
projection engaging a particular printed board contact structure.
U.S. Pat. No. 3,659,067 to Wilkinson, issued Apr. 27, 1972
discloses a U-shaped spring detent but the surface of the spigot is
different from the surface of the cutaway shaft of the present
invention and the caming surface of Wilkinson's member 18 has a
cutaway V-shaped section differing from the straight section of the
present invention.
In contrast to the prior art, the present invention provides a
relatively simple and inexpensive arrangement which fulfills the
necessary watch functions with a single stem assembly and provides
a four position rotary detent action with reliable electrical
connection between the stem and the case. The stem shaft of the
invention includes a rectangular section which cooperates with a
peculiarly shaped spring for detenting and axial biasing purposes
while a tab portion on the internal end of the shaft selectively
engages spaced watch blades.
Other prior art patents of interest include U.S. Pat. No. 2,616,994
to Luhn, issued Nov. 4, 1952, U.S. Pat. No. 3,699,763 to Zeph
issued Oct. 24, 1972, U.S. Pat. No. 2,545,548 to Gouffon issued
Mar. 20, 1951 and U.S. Pat. No. 3,499,133 to Tillack et al, issued
Mar. 3, 1970. These prior art patents are merely typical of the art
and are not in any way intended to be an all-inclusive list of
pertinent patents.
SUMMARY OF THE INVENTION
The present invention relates to a stem assembly for solid state
digital watches which comprises a stem having a shaft portion with
a knurled knob or crown mounted on the end thereof protruding from
the bezel and an elongated cylindrical shaft portion having an
intermediate rectangular section of lesser diameter in the portion
immediately inside the bezel and an eccentric tab at the internal
end thereof.
The rectangular portion engages a unitary stamped spring having two
spaced arm portions engaging opposite sides of the rectangular
section. The stem is locked axially in one of four positions by the
cooperating action of the spring arms and the rectangular section
which is smaller than the diameter of the shaft portion. The spring
also includes outwardly extending base portions at each end which
are biased against the case so that this preformed arrangement
provides high simultaneous contact pressure between both the stem
and detent and between the detent and case. In the embodiment
described above, good electrical connection is further enhanced by
the wiping action of the stem when rotated.
As a further feature, the eccentric tab on the end of the stem is
designed to engage one of three switch blades. Two of the blades
are positioned on opposite sides of the shaft and the third blade
is positioned intermediate the opposing blades and in a plane below
said blades. This arrangement permits setting and resetting the
watch or shutting down the watch in a unique and expeditious manner
by merely rotating the single stem to control the watch
circuit.
Accordingly, an object of this invention is to provide a new and
improved stem assembly for a solid state digital watch.
Another object of this invention is to provide a new and improved
detent arrangement for a solid state digital watch which also
provides reliable electrical connection between the stem and detent
and between the detent and case.
A further object of this invention is to provide a new and improved
single stem assembly means for setting, resetting, and shutting
down a solid state digital watch.
A more specific object of this invention is to provide a new and
improved stem assembly for a solid state digital watch which
includes a multi-position stem detent arrangement and an internal
switch arrangement in a rather advantageous and economical
design.
BRIEF DESCRIPTION OF THE DRAWINGS
Other objects and advantages of this invention may be seen more
clearly from the following description when viewed in conjunction
with the accompanying drawings wherein:
FIG. 1 is a perspective view showing the stem assembly and
cooperating portions of the solid state watch,
FIG. 2 is a view taken along the lines of 2--2 of FIG. 1,
FIG. 3 is a plan view showing a portion of the stem assembly
cooperating with the spring member in the vicinity of the watch
case,
FIG. 4 is a view taken along the line 4--4 of FIG. 3 showing the
detent contact pressure,
FIG. 5 is a view taken along the line 5--5 of FIG. 4, and,
FIG. 6 is a view similar to FIG. 5 showing the stem and
particularly the rectangular portion under rotation.
DETAILED DESCRIPTION OF THE INVENTION
Referring now to the drawings, the invention comprises a solid
state watch stem assembly 10 which includes an eccentric tab 11 at
one end, a main shaft portion 12, an intermediate rectangular
section 13 of lesser diameter than the shaft 12, and another end
portion 14 having the watch crown 16 affixed thereto outside the
case or bezel 17. As may be seen from FIG. 1, the eccentric tab 11
cooperates with the cantilevered switch blades 18 and 19 and 21 to
effect an electrical connection with predetermined portions of the
watch circuit.
The switch blades 18, 19, and 21 are thin beryllium copper
stampings riveted or soldered to the substrate 22 at points 23 and
24 and 26 respectively. The switch blade 18 is connected to an
integrated circuit chip (not shown) through printed circuit lead
27. Printed circuit leads 28 and 29 similarly connect switch blades
19 and 21 to the aforementioned chip which is located within the
plastic dam 31. A plurality of contact terminals 32 and their
respective leads 33 are shown in FIG. 1 but since they are not
pertinent to the present invention, reference must be made to the
co-pending application of the inventor's Ser. No. 462,151 filed
Apr. 18, 1974.
The switch blade 18 which is engaged by the tab 11 when the stem
assembly 10 is turned in that particular direction is designated as
the setting switch blade and is coupled to logic circuits (not
shown) to provide a capability off selectively advancing the
minutes or hours counters at 1Hz rate and/or to reset the seconds
counters to zero by manipulation of switch blades 18 and 21. Switch
blade 21 is characterized as the mode switch blade. Switch blade 19
is engaged by tab 11 when it is desired to shut down the watch.
The stem assembly 10 also permits detent holding of the stem in a
proper contact position and provides electrical contact to ground
the stem to the case. This is effected through the rectangular
section 13 which is smaller than the diameter of the shaft portion
12. The rectangular portion 13 engages a single stamped spring 34
to provide a four position rotary detent action. The spring 34
comprises a pair of spaced, substantially U-shaped arms extending
upwardly from the preformed base 36 of the spring 34. The opposing
legs 37 and 38 of the protruding contact members 39 and 41 are
spring biased into engagement with the rectangular section 13. As
can be noted from the drawings, particularly FIGS. 3-6, the spring
34 is preformed so as to exert a high simultaneous radial contact
pressure between the stem portion 13 and the arms 37 and 38 and
axial contact pressure between the base 36 of spring 34 and the
case 17. This electrical connection is further enhanced by the
wiping action of the stem when rotated.
FIG. 5 shows the rectangular section 13 of the stem 10 and
particularly edges 41 and 42 thereof in contact with the arms 38
and 37 with corner portions 43 and 44. It is to be noted that the
distance across the corners of the rectangular portion 13 is
smaller than the shaft diameter in order to provide a shoulder for
the arms 38 and 37 to bias the stem axially regardless of its
rotational position. The stem is prevented from moving axially
inward by the crown 16 against bezel 17, thus creating good contact
pressure between spring base 36 and case 17.
While the invention has been explained by a detailed description of
certain embodiments, it is understood that various modifications
and substitutions can be made in any of them within the scope of
the appended claims which are intended also to include equivalents
of such embodiments.
* * * * *