U.S. patent number 3,802,251 [Application Number 05/296,999] was granted by the patent office on 1974-04-09 for method and apparatus for testing a watch for tightness.
This patent grant is currently assigned to Hermann Becker K.G.. Invention is credited to Walter Durr.
United States Patent |
3,802,251 |
Durr |
April 9, 1974 |
METHOD AND APPARATUS FOR TESTING A WATCH FOR TIGHTNESS
Abstract
A watch movement is operated in an associated watch housing.
Said watch housing containing said operating watch movement is
subjected to an air pressure which differs from a normal or
atmospheric air pressure. Any change in the accuracy of the
operation of said watch movement in said housing when the latter is
subjected to said different air pressure compared to the accuracy
of the operation of said watch movement in said housing when the
latter is under said normal or atmospheric air pressure is
detected.
Inventors: |
Durr; Walter (Nottingen,
DT) |
Assignee: |
Hermann Becker K.G.
(Dietlingen, DT)
|
Family
ID: |
25761963 |
Appl.
No.: |
05/296,999 |
Filed: |
October 12, 1972 |
Foreign Application Priority Data
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Oct 28, 1971 [DT] |
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2153682 |
Apr 22, 1972 [DT] |
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2219771 |
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Current U.S.
Class: |
73/49.3; 968/755;
73/1.48; 73/1.51 |
Current CPC
Class: |
G04D
7/007 (20130101) |
Current International
Class: |
G04D
7/00 (20060101); G01m 003/02 () |
Field of
Search: |
;73/49.3,49.2,40,37,6 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Myracle; Jerry W.
Assistant Examiner: Roskos; Joseph W.
Claims
What is claimed is;
1. A method of testing a watch for tightness, which comprises
operating a watch movement in an associated watch housing,
placing said watch housing containing said operating watch movement
in a pressure chamber and subjecting said watch housing containing
said operating watch movement to an air pressure which differs from
atmospheric air pressure, and
detecting any change in the accuracy of the operation of said watch
movement in said housing when the latter is subjected to said
different air pressure compared to the accuracy of the operation of
said watch movement in said housing when the latter is under said
atmospheric air pressure.
2. A method as set forth in claim 1, in which said different
pressure is higher than said atmospheric pressure.
3. A method of testing a watch for tightness which comprises
operating a watch movement in an associated watch housing,
placing said watch housing containing said operating watch movement
in a pressure chamber,
changing the air pressure in said pressure chamber from atmospheric
air pressure to an air pressure which is different from said
atmospheric air pressure while said watch housing containing said
operating watch movement is in said pressure chamber, and
detecting any change in the accuracy of the operation of said watch
movement in said watch when the watch housing is subjected to said
different air pressure compared to the accuracy of the operation of
said watch movement in said watch housing when the watch housing is
under said atmospheric air pressure, comprising
converting acoustic oscillations produced by said operating watch
movement into electric signals when said watch housing in said
pressure chamber is under said atmospheric air pressure and under
said different air pressure, and
chronographically recording said electric signals to detect any
changes in the accuracy of the operation of said watch movement in
response to the change from said atmospheric air pressure to said
different air pressure in said pressure chamber.
4. Apparatus for testing a watch for tightness, which comprises
means defining a pressure chamber,
means for holding a watch housing containing a watch movement in
said pressure chamber,
means for subjecting said watch housing in said pressure chamber to
a pressure which differs from atmospheric pressure, and
means for detecting during the operation of said watch movement in
said housing in said pressure chamber any changes in the accuracy
of said operation when said housing is subjected to said different
pressure compared to the accuracy of the operation of said watch
movement in said housing when the latter is under said atmospheric
pressure.
5. Apparatus as set forth in claim 4 wherein
said means for detecting any change in the operation of said watch
movement in said watch housing includes a microphone which is
arranged to receive acoustic oscillations produced by said watch
movement when the same is operating in said pressure chamber and to
convert said acoustic oscillations into electric signals when said
watch housing in said pressure chamber is under said atmospheric
air pressure and under said different air pressure, and
a chronograph arranged to receive and record said electric signals
and to indicate any changes in the accuracy of the operation of
said watch movement in response to the change from said atmospheric
air pressure to said different air pressure in said pressure
chamber.
6. Apparatus as set forth in claim 5, in which
said microphone is contained in said pressure chamber and
electrically connected to said chronograph, and
a pressure gauge is connected to said pressure chamber.
7. Apparatus as set forth in claim 4, in which said means defining
a pressure chamber comprises a body having an opening and a sealing
cover adapted to seal said opening and provided with a sight glass
enabling an observation of said watch when the latter is supported
in said pressure chamber.
8. Apparatus as set forth in claim 5, which comprises a three-way
valve, which is shiftable between a first position for connecting
said pressure chamber to a source of compressed air and a second
position for pressure-relieving said pressure chamber.
9. Apparatus as set forth in claim 4, in which
said means defining a pressure chamber comprise a body having an
opening and a sealing cover adapted to seal said opening and
means are provided which are responsive to the pressure in said
chamber and adapted to force said sealing cover into sealing
engagement with said body with a force which increases in response
to a pressure rise in said chamber.
10. Apparatus as set forth in claim 9, in which said
pressure-responsive means include a force-increasing lever
means.
11. Apparatus as set forth in claim 10, in which
said pressure-responsive means comprise a piston which is
responsive to the air pressure in said pressure chamber and
said force-increasing lever means are adapted to increase several
times the force exerted on them by said piston.
12. Apparatus as set forth in claim 11, in which
said pressure-chamber defining means define a piston chamber,
said pressure chamber communicates with a passage for applying air
pressure to and for pressure-relieving said pressure chamber,
said piston chamber communicates with said passage,
said piston is contained in said piston chamber and responsive to
the pressure therein,
said lever means comprise a plurality of force-increasing levers,
and
said piston is arranged to exert on said levers a force which
varies with said pressure in said piston chamber.
Description
This invention relates to a method and apparatus for testing
watches, particularly wrist watches, for tightness.
When a wrist watch has been completely assembled in a watch
housing, it is conventional to test the watch for water- and
airtightness. For this purpose, the watch is placed in a water
container and the water pressure is increased. Watches which are
not tight thereafter contain water droplets in their interior. The
watches which are rejected for this reason must not only be
provided with a new housing seal but the watch movement must be
taken apart immediately and dried, re-oiled and reassembled. These
operations are time-consuming and expensive.
This disadvantage is eliminated by the present invention. The
method according to the invention is characterized in that the
watch housing which contains the watch movement, which is operated,
is subjected to an air pressure which differs from and preferably
exceeds the normal or atmospheric pressure, and changes in the
accuracy of the operation of the watch movement are detected. The
method may be carried out in that a watch housing containing a
watch movement is placed on a microphone to which an electronic
chronograph is connected, and the watch housing is subjected to
pressure changes in a pressure chamber while the electronic
chronograph is operated.
Apparatus for carrying out the method comprise suitably a
microhpone provided with a holder for carrying the watch housing
containing a watch movement, and means operatively connecting the
microphone to the electronic chronograph, which microphone is
contained in a pressure chamber provided with pressure gauge.
According to another feature of the invention, the apparatus
according to the invention is characterized in that a sealing cover
of the pressure chamber is connected to a linkage, which tends to
close the cover in response to an increase of the pressure in the
pressure chamber. To that end, the pressure in the pressure chamber
is applied to a piston, which is operatively connected to the
closing cover by linkage tending to exert on the cover a force
which acts in the closing sense and is several times larger than
the pressure force acting on the piston. This arrangement enables
an automatic opening and closing of the sealing cover during the
operation of the pressure chamber, i.e., the admission of the
compressed air and the pressure relief.
Further details of the apparatus according to the invention will be
described hereinafter with reference to the drawing, in which two
embodiments are shown by way of example.
FIGS. 1 and 2 are sectional views taken at right angles through a
first embodiment of the apparatus.
FIG. 3 shows test charts recorded during tests of two watches.
FIGS. 4 and 5 are sectional views showing the second embodiment of
the apparatus with the sealing cover in closed and open positions,
respectively.
FIG. 6 is a top plan view showing the apparatus of FIGS. 4 and 5
with the sealing cover removed so that the holder for the watch is
visible.
The first embodiment shown in FIGS. 1 and 2 comprises a pressure
chamber body 1 provided with a cover 2, which can be removed, e.g.,
unscrewed, and is provided with a sight glass 3. A pressure chamber
4 contains a retaining spring 5 for receiving a watch housing 6 to
be tested, which contains a watch movement. The watch housing is
engaged by transmission pins 7, which transmit the ticking of the
watch (this ticking is due to the oscillations of the balance
wheel) to a piezoelectric quartz 8. The oscillating quartz 8
converts the acoustic oscillations in known manner into electric
signals, which are conducted in known manner by the lead 9 to the
electronic chronograph.
Air pressure is applied to the pressure chamber 4 of the pressure
chamber body 1 along path A from an inlet pipe 10 through a
three-way valve 11, which is controlled by a switch 12. The
pressure rise is indicated by a pressure gauge 13. Air enters the
pressure chamber 4 through a nozzle 14 so that a too sudden
pressure change is avoided, just as during a pressure relief. The
pressure relief is initiated by a shifting of the three-way valve
11 so that the air can escape along path B through an outlet 15. If
the watch housing is tight, the record of the chronograph shows no
change in accuracy compared to normal pressure conditions. If the
watch housing is not tight, the test watch shows a distinct lag
because the oscillation of the balance wheel is influenced by the
changed pressure in such a sense that the watch is slower. This is
recorded or indicated by the chronograph. The sight glass 3 enables
an observation of the operation of the watch because if the watch
is tight the watchglass may press on the hands to stop the
watch.
FIG. 3 shows a chart plotting the records of two tested watches.
The change in accuracy reported as pitch difference in seconds per
day or .DELTA. s/d, is plotted as a function of the pressure rise p
(in kilograms per square centimeter) for a tight watch housing of
the first tested watch (curve a) and for the same watch housing
which has been rendered untight (curve b), also for a tight watch
housing of the second tested watch (curve c) and for the same watch
housing which has been rendered untight (curve d). It is apparent
that the untightness is indicated by a change in accuracy compared
to normal pressure.
The second embodiment shown in FIGS. 4 to 6 comprises a pressure
chamber body 21 and a removable cover 22, which is provided with a
clamping rim 23. There is no sight glass in this embodiment. A
pressure chamber 24 contains again a retaining spring 25 for
receiving a watch housing 26 to be tested, which contains a watch
movement. The watch housing 26 is engaged by transmission pins 27,
which transmit the ticking of the watch (this ticking is due to the
oscillations of the balance wheel) to a piezoelectric quartz 28.
These pins serve in this case also to hold the watch. By the
piezoelectric quartz 28, the acoustic oscillations are converted in
known manner into electric signals, which are conducted by a lead
29 to an electronic chronograph. Air pressure is applied to the
pressure chamber 24 in the pressure chamber body 21 from an inlet
pipe 30 along path A through a three-way valve 31, which is
controlled by a switch 32. The pressure rise is indicated by a
pressure gauge 33. Air enters the pressure chamber through a nozzle
34 so that there is no too sudden pressure change, just as during a
pressure relief. When the three-way valve 31 has been shifted,
pressure is relieved through an outlet 35 to the outside. The
effects regarding the accuracy of the watch when the watch housing
is tight and untight, respectively, are the same as described in
connection with the first embodiment.
In the second embodiment, a piston chamber 36 is disposed below the
pressure chamber 24 and is connected by a passage 37 also to the
passage through which compressed air is admitted and through which
the air is exhausted for a pressure relief. Such air thus acts on
the piston 38. The piston 38 comprises a sealing cup 39, which is
held by screws 40 and is engaged by, for instance, three clamping
levers 41, which also engage the clamping ring 23 of the sealing
cover 22 on the inside. When compressed air is admitted (path A in
FIG. 4), these levers serve to increase the sealing force. During a
pressure relief (path B), return springs 42 acting on the piston 38
return the latter so that the clamping levers 41 pivoted at 43
disengage the rim 23 and the cover 22 can be opened as is shown in
FIG. 5. The sealing cover 22 is thus automatically closed and
opened in response to the air pressure so that there is no need for
a manual unscrewing or unclamping and the manufacture in large
quantities is facilitated.
* * * * *