U.S. patent number 3,668,858 [Application Number 05/016,062] was granted by the patent office on 1972-06-13 for clock.
Invention is credited to Rudiger Hartwig.
United States Patent |
3,668,858 |
Hartwig |
June 13, 1972 |
CLOCK
Abstract
A clock in which planetary gear wheels provided with inner teeth
engage on stationary elements with outer teeth to obtain uniform
rotation for successive gear stages. The eccentric drive of one
stage necessary for engagement is directly effected by the
eccentric shape of the rotating element of the preceding stage. The
rotating elements belonging to each stage act as moving elements
and also as indicating elements due to their markings.
Inventors: |
Hartwig; Rudiger (7032
Sindelfingen, DT) |
Family
ID: |
5727003 |
Appl.
No.: |
05/016,062 |
Filed: |
March 3, 1970 |
Foreign Application Priority Data
|
|
|
|
|
Mar 4, 1969 [DT] |
|
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P 19 10 818.0 |
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Current U.S.
Class: |
368/77; 368/234;
475/158; 475/174; 968/140; 968/395 |
Current CPC
Class: |
G04B
19/02 (20130101); G04B 45/04 (20130101) |
Current International
Class: |
G04B
19/02 (20060101); G04B 19/00 (20060101); G04B
45/00 (20060101); G04B 45/04 (20060101); G04b
045/00 (); G04b 019/30 () |
Field of
Search: |
;58/2,7,50,25,125,152
;74/804 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Wilkinson; Richard B.
Assistant Examiner: Simmons; Edith C.
Claims
What I claim is:
1. A time-keeping instrument comprising
a case,
an outer toothed wheel rigidly attached to said case and arranged
coaxially about a first longitudinal axis,
a first time indicating element indicating the maximum unit of time
for the instrument and having a circular bore at its hub having a
second longitudinal axis which moves intermittently eccentrically
relative to said first longitudinal axis,
an inner toothed wheel rigidly connected to said first time
indicating element and having more inner teeth than the outer
toothed wheel has outer teeth and a larger diameter of contact than
the outer toothed wheel and being rolled on the outer toothed
wheel,
a second time indicating element indicating the next smaller unit
of time, supported by said case rotatably about said first
longitudinal axis and having a first circular disc engaging and
rotatably supporting said first time indicating element in said
circular bore and moving intermittently about the eccentricity of
the two longitudinal axes to drive said first time indicating
element, and having teeth at its circumference equal in number to
its time unit and having a second circular disc arranged coaxially
with said first longitudinal axis,
a knob rigidly connected to said second time indicating element for
turning same, rotatable coaxially with said first longitudinal
axis,
clock driving means,
a third element supported by said second disc and rotatable about
said first longitudinal axis, having teeth at its circumference
equal in number to the periodic driving frequency of said clock
driving means, one of said teeth being followed by a gap deeper
than the depth of the other teeth,
said clock driving means being laterally arranged and engaging the
teeth of said third element and also engaging a tooth on said
second time indicating element when engaging said gap.
2. An arrangement as claimed in claim 1 in which the circumference
of the third element is provided with teeth corresponding to the
number of seconds; an adjacent circumference of the second element
is provided with teeth corresponding to the number of minutes; the
teeth of the second and minute sections are supported on different
diameters; and a flank of only one tooth of the second section is
guided into a portion corresponding approximately to the diameter
on which are supported the teeth of the minute section.
3. An arrangement as claimed in claim 2, characterized in that the
two discs lie on the same side of the minute section in that the
second disc has a considerably larger diameter than the first disc
and in that the first disc is located on the second disc.
4. An arrangement as claimed in claim 2, characterized in that the
circumference of the second section and the minute section is the
outer circumference in each case, in that the minute section and
the second section are flat discs which are made of a transparent
plastics material for visual reading, and in that the external
diameter of the minute section is at the most the same as, the
internal diameter of the teeth on the second section.
5. An arrangement as claimed in claim 2 in which the teeth of the
second section are in the form of saw-teeth, and in that the teeth
of the minute section have a symmetrical shape.
6. An arrangement as claimed in claim 2 in which a radial slot is
provided in the case above the second section, and a strip the
lower edge of which is supported on the circumference of the second
section, is vertically movable through the slot.
Description
The invention relates to a mechanical arrangement for producing
definitely reduced rotary movements of indicating or control
elements operating successively in a plurality of stages,
particularly for clocks and control mechanisms.
The purpose of such arrangements is to convert a driving movement
into a series of definitely reduced rotary movements, the progress
or position of which can be visually read from outside by means of
pointers or dials or can be for example electrically tested by
means of contacts. In this connection, electrical or even
mechanical contact arrangements usually serve the more simple
purpose of actuating a control operation when a previously
indicated position has been reached.
It is known practice to use, for the purposes of reduction, gear
systems which consist of combinations of spur gears and worm wheels
successively arranged (clockwork mechanisms). It is also known
practice to provide, out of the usually large number of elements in
such a gear system, those whose movement is of direct importance
for indication with connecting elements (second, minute and hour
wheels), to guide them out for the purpose of indication and to
provide them with indicating elements (e.g. pointers). In addition,
there are known systems in which the driving elements are provided
with numerals on their periphery for the purposes of indication
(mechanical counters), but they operate preferably intermittently
to permit a clear reading and are designed for a series of
identical reduction ratios for adjacent indicating elements (e.g. 1
: 10).
Apart from the gear wheels which are essential for indication, the
use of spur gears only requires an additional number of
intermediate wheels to obtain a standard rotation for indication.
Furthermore, other elements are also required for guiding the
indicating means as well as for the indicating means itself. The
central indicating means in particular requires greater expenditure
as regards the number of elements and their arrangement. In
addition, further expenditure is necessary to permit adjustments
within such a mechanism to be made from the outside (e.g. to adjust
the minute hand) and this also affects the number of elements and
the structure of the entire system. With control clocks it is known
to provide a series of pre-selectable contacts over the periphery;
however, these permit only a limited solution and therefore only a
limited number of pre-selection times.
The problem underlying the invention is to provide an arrangement
which minimizes the necessary number of such systems, to design the
driving system so that possible divisional inaccuracies in
components only produce minor errors, to substantially reduce the
cost of manufacturing individual parts of the systems as well as
assembly costs and possibly to permit even fully automatic
assembly. Moreover, operations for example, when using a control
clock can be accurately pre-selected to the minute or even to the
second without causing a considerable increase in mechanical
expenditure. Finally, a spring second pointer is obtained when used
as clockwork and can also be adjusted in the second pointer when
designed as a synchronous clock and can be synchronized, for
example, with the television clock. All these requirements are
fulfilled without departing from the normal appearance of the
central pointer arrangement.
This problem is solved in accordance with the invention in that
planetary gear wheels provided with inner teeth engage on
stationary elements with outer teeth to obtain uniform rotation for
successive gear stages in a modification of the basically main
embodiments, the eccentric drive of one stage necessary for
engagement being directly effected by the eccentric shape of the
rotating element of the preceding stage. Because modified planetary
gear stages are used in this manner, the same direction of rotation
is directly obtained, and the number of moved elements in every
stage may be reduced to a minimum (to one). Furthermore, high
reduction ratios may be easily achieved in one stage (e.g. 1 : 60
in a clock) since the difference in the number of teeth is
essential for the degree of reduction (but not the quotient). The
use of such stages in reduction makes it possible, if required, to
provide teeth on a large segment of a circle, even outside the
indicating field, and thus reduces the problems of tooth size as
well as the effect of inaccuracies in the shape of teeth.
Another feature of the invention is that the rotating elements
belonging to each stage act as driving elements, on the one hand,
due to being the appropriate shape for that purpose and, on the
other hand, as indicating or control elements due to their
appropriate markings. Because of the central arrangement of all
rotating elements which results from using such planetary gear
stages, the rotating elements may be co-ordinated with the
exception of driving and indicating operations and, in addition,
control operations may be co-ordinated with likewise centrally
arranged counter elements evenly distributed, for example, over the
periphery of the frame. All additional elements are thereby
rendered superfluous, i.e. those which are normally required to
guide the indicating means, as an indicating element and, if
necessary, as additional control wheels.
Another feature of the invention is that the elements provided with
outer teeth for a plurality of successive gear stages are combined
in the same component, and said component can also be the housing
or frame of the clock. Thus several or even all the stationary
elements in the form of individual parts which would have to be
present at least once in every stage of reduction are omitted.
Other features of the invention are that a transmitting element
operates between the two rotating elements to transmit rotation
from an eccentrically rotating element to a concentrically rotating
element, which is to be driven at the same speed, within the same
stage of reduction, said transmitting element being flexible in a
radial direction, but tangentially rigid; that this element is
designed as a detachable connection to vary the relative position
of the two elements; that this element is a component of one of
those elements which it connects. In this way the radial distance
between the elements which is produced by the eccentric movement of
the rotating element can be flexibly adjusted and balanced and at
the same time, the rotary motion can be transmitted; that a
relative adjustment between the two elements can be effected by
disengaging the detachable connection; and that nevertheless no
additional component is required.
Other features of the invention are that the rotating elements
acting at the same time as driving and indicating elements are made
of a transparent material and provided with appropriate externally
visible markings; that the face showing the markings appears
luminous as a result of the light guide effect produced by the
appropriate shape of the surface when the light is projected from
the side. Therefore, although the driving elements overlap one
another, they can at the same time function as indicating elements;
that the entire system, with the exception of the dial and pointers
is transparent; and that in darkness only the dial and the hands
are luminous when illuminated from below.
Another feature of the invention is that to use the rotating
elements as control elements, the elements provided with outer
teeth on the housing or another circle covered by the rotating
elements are provided with contacts which can be externally tapped
and insulated from one another, said contacts closing an electric
circuit when touching the electrically conductive opposite contact
on the rotating element. Thus, pre-selection for the control
operation can be effected in a plurality of planes; reduction can
be increased in any desired manner and, for example, in the case of
the clock brings about pre-selection of the control operation
accurate to the second by also providing the second-wheel with such
means.
Another feature of the invention is that, when used as a clock, the
rotating element used to indicate the seconds is tangentially
driven via step-shaped teeth by a periodic lifting movement,
whereupon a split second movement is executed particularly by 60
teeth on the driving wheel. A continuous or split second movement
may be obtained thereby depending on the number of step-shaped
teeth and the corresponding distance and frequency of the lifting
movement.
Another feature of the invention is that a suitable adjusting
element to be externally actuated acts upon the rotating element to
adjust the second-hand and turns said rotating element in any
desired manner independently of its drive. When using a drive with
a power supply (synchronized clock) the second-hand can also be set
during operation for a normal clock, for example, the television
clock.
Other advantages and features of the invention are shown in the
following description of three preferred embodiments.
FIG. 1 shows a concentric longitudinal section, true to scale,
through the case of the clock, the drive and support having been
omitted;
FIG. 2 shows an enlarged section of an assembly along the line 2--2
shown in FIG. 1;
FIG. 3 shows a view of the front section, true to scale, according
to the arrow A in FIG. 1;
FIG. 4 shows a view of the minute section, true to scale, according
to the arrow A;
FIG. 5 shows a view of the second section, true to scale, according
to the arrow A;
FIG. 6 shows a view of the hour section, true to scale, according
to the arrow A;
FIG. 7 shows a view of the rear of the case, true to scale,
according to the arrow B;
FIG. 8 shows a concentric vertical section, true to scale, through
the case of the clock in a second embodiment, the drive and support
having been omitted;
FIG. 9 shows a view of the second, minute and hour sections
according to the arrow C in FIG. 8, but in a staggered relationship
to one another;
FIG. 10 shows an enlarged partial section of the driving portion of
the clock;
FIG. 11 shows a concentric extended vertical section, true to
scale, through the case of the clock in a third embodiment, the
drive and stand having been omitted;
FIG. 12 shows an exploded perspective view of the clock according
to FIG. 11;
FIG. 13 shows a section similar to FIG. 11, but with the clock
having been assembled;
FIG. 14 shows a general perspective view of the clock together with
the stand;
FIG. 15 shows a front view of the clock;
FIG. 16 shows a perspective view of the clock similar to FIG. 14
before the case is mounted on the stand.
All the parts described below are produced by injection moulding
and are made of a plastic glass. They can be already assembled, but
in case assembly may be wrongly effected, they may be delivered
individually to the user so that he may assemble them himself.
A square front section 11 has a circular bore 13 with a center
about a first geometrical longitudinal axis 12. A dial 14 divided
into the usual 12 hours is provided symmetrical to the longitudinal
axis 12.
A minute section 16 comprises a disc 17 which is symmetrical to the
geometrical longitudinal axis 12 and can be rotated about said
axis, the outer periphery 60 of said disc having upwardly pointing
rectangular teeth 18 of equal size which are supported on a
diameter 19 measured from the longitudinal axis 12. Moulded to the
left-hand side shown in FIG. 1 is a knob 21 which penetrates the
bore 13 and with which the minute section 16 can be adjusted at
random. To the right-hand side of the disc 17 is moulded a disc 22
coaxial with the longitudinal axis 12, said disc 22 being in the
vicinity of the hub of the disc 17 and its height being greater
than the width of a second section 23. The disc 22 is connected to
a disc 24, the latter having its center in a second longitudinal
axis 26 which is eccentric to the first longitudinal axis 12. It
also has a smaller diameter than the disc 22. As can be seen in
FIG. 4, it is arranged so that the outer circumferences of the two
discs 22, 24 are never aligned, but a step 27 always remains at the
narrowest point. The disc 24 is approximately the same height as
the disc 22. On the disc 17 there is a minute hand 28 which can be
integral with said disc, adhesively attached thereto, etc.
The second section 23 comprises a disc 29, the external diameter of
which is slightly greater than that of the disc 17. Its outer
circumference is provided with 60 identical saw-teeth 31 extending
in the same direction, the only exception being the shape of a
saw-tooth 32. With the exception of the latter all the saw-teeth
are supported on the same diameter 33 which is greater than the
diameter 34 of the minute section 16. The flattened-out flank 36 of
the tooth 32 extends so far into the disc 29 that a carrier 38
located on the base 37 of the flank 36 and shown by broken lines in
FIG. 7 can pass together with its projecting end 39 between two
teeth 18 of the minute section 16 and move the latter and the
second section 23 by the length of one tooth. A second hand 41 of
the disc 29 points in almost exactly the opposite direction to the
saw-tooth 32. The disc 29 which is coaxial with the longitudinal
axis 12 has a circular bore 42 and is rotatably guided therewith
over the circumference of the disc 22.
An hour section 43 comprises a disc 44 having a smooth outer
circumference. As can be seen in FIG. 1, this disc 44 has the
smallest diameter of all the discs 17, 29. An hour hand 46 is
provided thereon and an inner toothed wheel 47 having twelve
identical inner teeth 48 is moulded in the form of a hub to the
disc 44. The inner toothed wheel 47 is coaxial with the
longitudinal axis 26, and likewise the circular bore 49 by means of
which the hour section 43 is supported on the eccentric disc 24
with a minimum of play.
A rear wall 51 of the clock case has a slightly bigger base 52. It
has the same outer shape as the front 11 of the case and a circular
recess 53 coaxial with the longitudinal axis 12, into which fit all
the discs 17, 29, 44. Also coaxial with the longitudinal axis 12 is
a pin 54 which penetrates, but does not touch the bore 42, 49 and
extends into a coaxial pocket hole 56 of the minute section with a
minimum of play. A toothed wheel 57 having outer teeth 58 is
introduced into the base 52. As can be seen in FIG. 2, the outer
teeth 58 are in the form of small cylinders and the inner teeth 48
have corresponding flanks. The shape of the teeth is not important;
other more common shapes could be selected for the teeth. The wheel
57 has eleven outer teeth 58 which are identical in shape and
evenly distributed around the circumference. Around the toothed
wheel 57 there is provided a recess 59 in which the inner toothed
wheel 47 is accommodated. A driver 38 shown by broken lines is
inserted e.g. in channels 61, which driver can be moved back and
forth by a drive according to the double arrow 63 and extends
approximately tangentially to the disc 29. At the top there is
provided a radial slot 64 through which a strip 66 is guided, and
can slip partially downwards and move up and down over the
circumference of the disc 29. The minute section 16 has an unshown
overlocking device which co-operates with the teeth 18.
The clock operates as follows:
Every second the driver 38 moves to the left and carries the disc
29 through 6.degree. along the steep side of the saw-teeth 31, 32.
On the return movement the projection 39 slides upwards along the
flat side of the teeth 31, 32 and the strip 66 prevents a reverse
rotation. When the projection 39 moves into the base 37 of the
saw-tooth 32 it only carries the disc 17 of the minute section 16
in this case because it can pass between the teeth 18. If,
therefore, the disc 29 passes through 360.degree., the disc 17 is
moved through 6.degree. with spasmodic accuracy at the point
between the final second of the preceding minute and the first
second of the following minute.
The eccentric disc 24 attached to the minute section 16 together
with the bore 49 of the hour section 43 causes the inner toothed
wheel 47 to rotate about the toothed wheel 57 once every minute.
Assuming that rotation takes place in the direction of the arrow
68, after rotating for 1 hour a given inner tooth 67 is no longer
located at the point shown in FIG. 2, but at that point which is
occupied by a special inner tooth 69 in FIG. 2. Thus the hour
section 43 has moved in a clockwise direction through 30.degree..
In this connection the longitudinal axis 26 is moved on the circle
65 shown by a broken line in the direction of the arrow.
The described invention is suitable for conventional 12 -hour, 60
-minute and 60-second clocks, but it can be easily modified if a 24
hour, hundred-minute and a hundred second clock is required. For
example, 24 outer teeth 58 and 25 inner teeth 48 would then have to
be provided.
If the clock is not to be read directly, but used for example as a
control clock, the pointers 28, 48, 46 can be replaced by
corresponding contacts. In the case of the clock it is possible to
accept unusually large tolerances in manufacture. The sequence of
the discs 17, 29, 44 can be altered, for example, by positioning
the disc 24 on the left-hand side of the disc 17. Furthermore, the
rear wall 51 can be designed as a clock face so that the front
section 11 constitutes the base in this case. The front section 11
and the rear wall 51 of the clock are rigidly and, if necessary,
releasably connected by unshown means.
The advantage of the clock described is that it can be turned back
or adjusted by the knob 21, since rotation of the minute section 16
causes a corresponding rotation of the hour section 43. In cases
where it is unnecessary for the clock to be turned back or adjusted
or where another form of adjustment is possible, the second
embodiment according to FIGS. 8 to 10 is suitable. FIG. 8 shows the
front section 11, the rear wall 51, and the recess 53 in which fit
the second section 23, the minute section 16 and the hour section
43. There is only a single longitudinal axis 12 in relation to
which the pin 54 is coaxially arranged in the recess 53 and the
second section 23, the minute section 16 and the hour section 43
are rotatably mounted in corresponding concentric bores. The
circumference of the second section 23 is also provided with teeth
31, in addition to which there is the tooth 32. However, in
contrast to the first embodiment the flank 36 is considerably more
inclined and extends so far into the second section 23 that, as can
be seen particularly clearly in FIG. 10, a pawl or catch 71 can
move as far as the teeth 72 of the hour section 43. This can only
be achieved if the point 73 is located in the base 37 of the tooth
32 and if at the same time the minute section 16 has a tooth 74
with a flank 76 which is not so deeply recessed as the flank 36. As
can be seen from the drawings, the minute section 16 is also
provided with saw-teeth. The saw-teeth of the second section 23,
the minute section 16 and the hour section 43 all extend in the
same direction. As can be seen in FIG. 9, 11 teeth 18 are located
between two teeth 74 of the minute section 16. Every 12th tooth
therefore has a special shape which means in the practical
embodiment that every 12 minutes the point 73 can engage in both
the tooth 32 and in one of the teeth 74 so that the hour section 43
is moved by the length of one tooth every 12 minutes. The
circumference of the second section 23 is provided with 60 teeth,
as is the minute section 16 which includes specially shaped teeth.
The hour section 43 is also provided with 60 teeth, all being
identical in shape. In this connection the discs are made of a
transparent plastics material so that the associated pointers are
externally visible.
As can be seen in FIG. 10, the pawl 71 can execute a pivoting
movement according to the curved double arrow. Furthermore, it can
perform a lifting movement according to the straight double arrow.
The necessary means for preventing rearward movement are not shown.
These can have a variable shape and the drive of the clock can also
be different in design. The upper end of the point 73 has a
straight cutting edge, but the second, minute and hour sections,
23, 16 and 43, could be given the same external diameter and a
correspondingly stepped cutting edge could be used in place of a
straight cutting edge. The hour section 43 in the embodiment moves
through 6.degree. every 12 minutes. In this case therefore the hour
section 43 can be accurate to the second when springing into the
hour position.
The units of time in the embodiment are seconds, minutes and hours,
but other units of time could also be used such as for example, a
third of a second or 2 seconds etc. The number of teeth would then
be altered accordingly.
The third embodiment according to the FIGS. 11 to 16 is suitable
when it is intended to drive the part showing the lowest unit of
time, i.e. the second section 23 in the embodiment. In the drawing
the shapes of the front section 11 and the rear wall 51 have been
exchanged and the pocket hole 56 is a circular bore in this case.
On the front section 11 of the clock are shown the stationary pins
54 and the toothed wheel 57 with 11 outer teeth 58, the 12 inner
teeth 48 of the inner toothed wheel 47, the bore 49 and the
hour-hand 46. A toothed wheel 77 having 59 outer teeth 78 is
concentric with the longitudinal axis 12 on the front section 11 of
the clock. The minute section 16 has a peripheral edge 79 which is
concentric with the longitudinal axis 12, and a resilient
transmitting element 81. Between the minute section 16 and the
second section 23 there is an intermediate ring 82 bearing an
externally smooth inner toothed wheel 83 which projects to the left
as shown in FIG. 11 and has 60 inner teeth 84. The inner teeth 84,
cooperate with the outer teeth 78 in the same manner as the inner
teeth 48 cooperate with the outer teeth 58. The inner toothed wheel
83 engages with a minimum of play in an outer ring 86 which is
eccentric with the geometric longitudinal axis 12. The ball 42 is
concentric with the longitudinal axis 12. These drawings are shown
true to scale, but the eccentricities have been deliberately
magnified. They transmit only 1/120 (in the case of 1:60) or 1/24
(in the case of 1:12) of the diameter of the ring. In the case of a
dial having a diameter of approximately 12 c.m., an eccentricity of
only 1 m.m. is produced for both eccentrics and is proportionally
less for smaller embodiments.
The operation of the mechanism is described with the aid of FIGS.
11 and 12. A lifting movement every second serves as a drive
according to the arrow 87 and acts tangentially on the second
section 23. In this way the second section 23 rotates jerkily
through one sixtieth of a revolution per second. At the same time
the eccentric arrangement of the outer rings 86 which slides over
and engages the intermediate ring causes the latter to rotate about
the toothed wheel 77 through only one sixtieth of a revolution
whenever the second section 23 completes a full revolution. The
resilient transmitting element 81 on the minute section 16 which is
easily guided to the left and right engages in the inner teeth 84
of the intermediate ring 82 and transmits the rotary movement of
the intermediate ring 82 to the minute section 16. Therefore the
minute section 16 rotates concentrically at the speed of the minute
hand. The eccentric disc 24 on the minute section 16 which slides
into the bore 49 causes the inner teeth 48 of the hour section 43
to rotate on the outer teeth 58 of the toothed wheel 57. In this
way, whenever the minute section 16 completes a full revolution,
the hour section 43 rotates through one twelth of a revolution,
therefore at the speed of the hour hand. The hour section 43 is the
only one of the three indicating elements in which a slight
eccentric movement is added to the rotary movement, but this is in
no way detrimental to the hour section because of its very slow
speed. The minute section 16 is adjusted from the outside by the
knob 21, the resilient transmitting element 81 engaging on any of
the inner teeth 84 of the intermediate ring 82. Since the
intermediate ring 82 has a total of 60 teeth, automatic adjustment
can only be effected in complete minutes. Therefore the minute hand
28 always points exactly to a minute mark when the second hand 41
passes through 12. This clear coordination between the two pointers
is not possible with clocks having the means for continuous
adjustment.
All the reduction teeth can be arranged outside the field of
vision, as is the case with the teeth 78, 84, in the ratio of
59/60. For the minute/hour reduction 55/60 teeth would be
preferable to 11/12 teeth.
FIG. 14 shows a clock with such a driving means. The drive can be
effected e.g. by a synchronous motor, the speed of which is reduced
from e.g. 50 revolutions per second to one revolution per second by
a further stage in the planetary gear being flat in design, said
two parts being inserted in a base stand 88. FIGS. 15 and 16 show
basically how the transmission from the base stand 88 to the
mechanism of the clock can be effected and also show how simply the
wheels are connected to the driving system. The position of the
second-hand 41 can be altered independently of the drive by a
simple hand-operated advance mechanism e.g. in the form of an
externally operated pressure rod system which is provided with a
re-setting spring and, when actuated, has a rotating effect on the
second section 23. In this case also step-wise adjustment is only
possible in complete seconds since 60 teeth 31 are provided on the
circumference of the second section 23. This means that whenever
this clock is adjusted to a normal clock having a spring second,
the phase between the second hands of both clocks remains the same
in any other position, once it is correctly adjusted.
The illustrated embodiment also acts as a control clock if the
teeth on the front section 11 of the clock are in the form of
contacts which are insulated against one another and can be
connected to an outer circuit e.g. by small plugs or an adjustable
sliding contact. Every point on the inner teeth of the hour section
43 and the intermediate ring 82 must also be conductive and in
addition conductively connected. When the previously connected
contacts on the front section 11 reach the conductive points on the
hour section 43 and the intermediate ring 82, the circuit is closed
and the control operation is performed with accuracy to the minute.
By also providing the second section 23 with corresponding contacts
an embodiment showing accuracy to the second may be also obtained
by an extended series connection. The contacts for all
pre-selection planes and their leads can be fitted in the front
section 11 of the clock.
* * * * *