US 3686879 A
An alarm clock with coaxial digit wheels for one-minute, ten-minute and hour indications has a pair of contact-carrying disks, rotatable about the same axis, mechanically coupled with the 1-minute wheel and with the hour wheel, respectively, for entrainment thereby. Each disk confronts an associated selector drum bearing minute and hour indications, respectively, these disks being independently settable to display the time when the alarm is to ring. Each drum consists of insulating material and carries a terminal of an alarm circuit positioned to engage a contact near the periphery of the associated disk whenever the latter occupies a position corresponding to the selected drum setting; the disks are always conductively interconnected, by a contact spring on one disk engaging a metallic track on the other disk, so that the alarm circuit is completed when both disks occupy their preselected positions. With the digit wheels and the drums stepped intermittently, at 1-minute intervals in the case of the wheel of lowest denomination, the alarm circuit is reopened after a minute.
Description (OCR text may contain errors)
United States Patent Hummel et al.
[ Aug. 29, 1972  DIGITAL CLOCK WITH ALARM  Inventors: Gunter Hummel, Carl-Benz-Strasse 6, D-755 Rastatt, Baden; Erich Scheer, Bergstrasse 28, D-7744 Peierzell, Black Forest, both of Germany 22 Filed: Dec. 28, 1970 21 Appl.No.: 101,974
 Foreign Application Priority Data Dec. 27, 1969 Germany.....-.'....P 19 65 205.2 April 26, 1970 Germany ..P 20 20 214.6 52 u.s. c1. ..58/38, 58 19 R, 58/126 E, 235/1 0 51 int. Cl. ..G04c 21/00, G04c 21/16  Field ofSearch ..58/38, 19 R, 23 R, 125 R, 58/125C,126R,l26A,l26E,4R,6R, 20,21;235/1c  ReierencesCited 3 UNITED STATES PATENTS 2,539,138 1/1951 J61ms6n...........; ..58/19 R 3,495,396 2/1970 Funaki ..58/19 R 3,597,918 8/1971 Robinson ..58/125 R 3,609,956 10/1971 Funaki. ..58/20 FOREIGN PATENTS OR APPLICATIONS 485,476 8/1952 Canada ..58/125C Primary ExaminerRichard B. Wilkinson Assistant Examiner-John F. Gonzales Attorney-Karl F. Ross  ABSTRACT An alarm clock with coaxial digit wheels for oneminute, ten-minute and hour indications has a pair of contact-carrying disks, rotatable about the same axis, mechanically coupled with the 1-minute wheel and with the hour wheel, respectively, for entrainment thereby. Each disk confronts an associated selector drum bearing minute and hour indications, respectively, these disks being independently settable to display the time when the alarm is to ring. Each drum consists of insulating material and carries a terminal of an alarm circuit positioned to engage a contact near the periphery of the associated disk whenever the latter occupies a position corresponding to the selected drum setting; the disks are always conductively interconnected, by a contact spring on one disk engaging a metallic track on the other disk, so that the alarm circuit is completed when both disks occupy their preselected positions. With the digit wheels and the drums stepped intermittently, at l-minute intervals in the case of the wheel of lowest denomination, the alarm circuit is reopened after a minute.
21 Claims, 12 Drawing Figures PAIENTED Z IH 8.686.879
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sum s ur s GUnfer Humme/ Erich Scheer INVEN T0 P3.
Attorney DIGITAL CLOCK WITII ALARM Our present invention relates to an alarmclock or, more generally, to a timepiece wherein a load circuit is temporarily closed at a predetermined time to operate a controlled device. Such a system may be used, aside from alarm purposes, for timing a photographic exposure, for reading a laboratory instrument, or for carrying out any other operation beginning and ending at precisely predetermined instants.
More particularly, our invention concerns a preferably electrically driven timepiece of the digital type, i.e. a clock with a set of operatively interconnected digit wheels displaying time indications of different denominational orders in a window of a housing, such as the units and tensdigits of the minutes and corresponding numerical values for the hours.
The display mechanism of such a digital clock normally performs a complete cycle every 12 or 24 hours and may be adjustably coupled witha'separate drum making a single revolution in the course of such a cycle, this drum carrying a mobile contact which makes with an associated stationary contact once per cycle to close the alarm circuit. It isevident, however, that such a drum would have to be uncommonly large in order to accommodate, on its peripheral surface, all the minute and hour markings for a 12-hour or 24-hour period, i.e. 720 or 1440 markings, and to be indexable in as many angularpositions for a presetting of the alarm with 1- minute accuracy.
It is, therefore, thegeneral object of our present in vention to provide a relatively simple and compact mechanism in such a digital clock for facilitating the exact preselection of the instant when the alarm or other controlled device is to be energized, with a freedom of choice determined by the minimum time increment (e.g. a minute) measured by, the system, and with an accuracy equal to that of the clockwork itself,
' for a period of 12 hours, 24 hours or any multiple thereof. 7
A more specific object of this invention is to provide an alarm system or the like which becomes active, at
the preselected time, for a precisely fixed operating period, preferably 1 minute.
These objects are realized, pursuant to the present invention, by the provision of two contact carriers and two rotary selectors coaxially juxtaposed therewith, each selector being independently settable to any one of a multiplicity of angular positions in which it is retained by friction or by suitable indexing means. The
' two contact carriers, which are preferably disk-shaped and will be referred to hereinafter as disks, are positively linked with the lowest-ranking and a higher-ranking digit wheel of the display unit, respectively, generally the 1minute wheel and the hour wheel. As the rate of rotation of the disk entrained by the hour wheel is an aliquot fraction of the rate of rotation of the disk entrained by the l-minute wheel, the latter will perform several (usually 12 or 24) full revolutions per operating cycle while the former makes only one turn in the course of such cycle. Only once per cycle, therefore,
will the two disks simultaneously occupy predetermined positions relative to the associated selectors in which coacting contacts on the two disks and the two selectors establish a connection to complete an external load circuit including, for example, an alarm device. The time of occurrence of such-a relative position depends, of course, on the presetting given to the two selectors which are advantageously calibrated in minutes and hours, respectively. Thus, the alarm will go ofi at exactly the instant when the hour and minute settings of the selectors match the digital reading of the clockwork, the circuit being broken as soon as the parts move out of that relative position. If the clockwork is conventionally stepped so that itsreading changes only once per minute, the coincidence position and therefore the operation of the alarm will last for exactly 1 minute. Such a stepping drive, causing successive jumps of each digit wheel or reel by one division, is well known in decimal counters or registers; it may include a single tooth on an input member periodically engaging the gear coupled with the digit wheel, a stepping pawl controlled by an electronically pulsed balancer, or a Geneva movement.
While for alarm clocks it will generally be sufficient to span a period not greater than 24 hours, this period could evidently be extended to, say, a week or a month by. a modification of the time base of the controlling digit wheels and/or by the inclusion of a further selector and disk in series with the two mentioned above, this further disk being entrained by a digit wheel of still higher denominational order counting, for example, the number of days.
In an advantageous embodiment, designed to facilitate mass production of the parts, the two carrier disks are of identical basic construction including each a body of dielectric material with conductive facings on opposite surfaces and with throughgoing metallic connectors therebetween; one of the facings of each disk, on the side remote from the other disk, forms part of a contact spring projecting axially toward the associated selector which also has an insulating body formed with a peripherally located discontinuity in its insulation, the contact spring engaging this discontinuity once per revolution to extend the circuit. The discontinuity may be simply a hole through which a contact spring can reach an underlying conductive surface, but in a preferred construction it is constituted by a metallic rivet with a first head contacting such a surface and a second head engageable by the contact spring of the disk. The metallic facings on the two confronting disk sides are designed to provide a permanent conductive connection between the disks, one of these facings having the shape of an annular track while the other facing forms a contact spring engaging that track in any relative position of the two disks.
The above and other features of our invention will be described in detail hereinafter with reference to the accompanying drawing in which:
FIG. 1 is a front-elevational view (with parts broken away) of a digital clockwork provided with an alarm mechanism according to our invention;
FIG. 2 is a bottom view of the assembly of FIG. 1;
FIG 3 is an enlarged sectional elevation of the alarmcontrol stage of the assembly of FIGS. 1 and 2;
. FIG. 4 is a face view of one of the elements of the unit shown in FIG. 3;
FIG. 5 is a face view of another element of that unit;
FIG. 6 is a cross-sectional view taken on the line VIVI of FIG. 5;
FIG. 7 is a face view of a metal ring fitting into the element of FIGS. 5 and 6;
FIG. 7a is a side view of the ring of FIG. 7;
FIG. 8 is a view similar to FIG. 5, showing the parts of FIGS. -7 in an assembled condition;
FIG. 8a is a cross-sectional view taken substantially on the line VIIIA-VIIIA of FIG. 8;
FIG. 9 is a view similar to FIG. 8, for a companion element; and
FIG. 9a is a cross-sectional view taken on the line IXA-IXA of FIG. 9.
In FIGS. 1 and 2 we have shown parts of the housing of an electric digital clock including a bracket 1 with two upstanding arms 2, 3. This housing has a window, not shown, for displaying the time of day (here 16:36 hours or 4:36 PM) in the form of digits carried by three coaxial wheels 4, 5 and 6. Digit wheel 4, bearing the numerals 0 to 9, and digit wheel 5, bearing the numerals 0 to 5, show the minutes; digit wheel 6 displays the hours with the aid of eight peripherally mounted prismatic bodies of which three, designated 8, 9 and 10, are visible in FIG. 1. These bodies are in the form of regular three-sided pyramids and, as particularly illustrated for body 10, are provided with star wheels 10' having three angularly equispaced pins engageable by a fixed stud 11 in a stationary end cap 11 secured to arm 2. Thus, during any revolution of wheel 6, any digit carrier 8, 9, 10 etc. is tripped on passing through its nadir position and rotated through 120 to exhibit a new face to the observer; these faces, 24 in all, carry the numerical designations from O0 to 23. Naturally, the 24 hour readings could also be designated 1 AM to 12 AM and 1 PM to 12 PM. Each digit carrier may be held in its position relative to wheel 6, for a full revolution of that wheel, by friction or with the aid of indexing means not shown.
Bracket 1 supports, via posts 13 and screws 14, a similar, smaller bracket 15 having upstanding arms 16 and 17. The hour wheel 6 is freely rotatable on a fixed shaft 7 extending between uprights 2 and 16; the interior of this hollow wheel, whose concave side confronts the lO-minute wheel 5, may contain a Geneva-type or other conventional transmission for stepping the wheel 6 through a fraction of a revolution upon completion of any full turn by the wheel 5, i.e. whenever the latter wheel returns to its zero position. In the present instance, with eight ancillary digit carriers 8, 9 etc., the wheel 6 is stepped through one-eighth of a turn once per hour, i.e. through 45; in the more general case, the wheel 6 performs one revolution every n hours where n is the number of ancillary carriers each having 24/n (here 3) digit-bearing faces. Digit wheel 5 has a shaft 18 journaled in arms 16, 17 and traversing the arm 3, together with a hub 19 of digit wheel 4 which is freely rotatable on shaft 18. The two digit wheels 4, 5 are intermittently advanced by a stepping drive including a synchronous electric motor 22 and a gear train 23-29; the stepping mechanism proper, driven by this gear train, includes gears 30, 30a, 30b and may be of the aforedescribed type conventionally used in the numerical registers of adding machines and the like.
The arm 3 of bracket 1 is broadened to serve as a mounting plate for the motor 22 and other parts of the stepping drive, the motor having a base 31 supported on plate 3 by posts 21. Two further mounting plates 33, 34 are secured to plate 3 by means of mounting bolts 32 surrounded by tubular spacers 35.
In order to permit manual resetting of the clockwork, the digit wheels 4, 5 are 6 and independently adjustable with reference to the observation window of the housing and can be locked in their newly selected relative position by nonillustrated indexing means known per se.
Mounting plates 33 and 34 define a compartment for a unit, more fully illustrated in FIG. 3, which controls the closure of an alarm circuit including a power source 101, a bell or buzzer 102, and a manual circuit breaker 103 assumed to be closed. This circuit is connected across a pair of binding posts 55, 55' fixedly held in mounting plates 33 and 34, respectively. These mounting plates are provided with a pair of fixed coaxial sleeves 41, 42 which receive gudgeons 43, 44 of an axle 40 and which carry a pair of fixed but resiliently deformable indexing plates 49, 50 of insulating material provided on their confronting surfaces with conductive annular zones 51, 51'. As illustrated in FIG. 4 for the plate 49, the plates 49, 50 may be formed with large cutouts 49a to increase their resiliency. The sleeves 41 and 42 further receive hubs 45, 46 of a pair of insulating selector elements 37 and 36, respectively, which are generally cup-shaped with outwardly facing concarities embracing the indexing plates 49 and 50. The elements 37 and 36, which will be referred to hereinafter as drums, have end walls 53, 54 each formed near its periphery with an annular array of corrugations 56, 56' engaged by the rounded extremity 57 or 57 of the associated binding post 55 or 55', the latter being secured to the corresponding indexing plate 49, 50 whose resiliency tends to maintain the extremities 57 or 57' in engagement with the corrugated surface 56 or 56'. The corrugations of this surface are as numerous as the angular settings of the corresponding selector drum, namely 24 in the case of the hour drum 36 and 60 in the case of the minute drum 37. To facilitate the manual setting of either drum, their outer peripheries are provided with gear teeth 60 and 61 respectively engaged by a pair of independently rotatable toothed wheels 37a, 36a partly projecting from the clock housing Posts 55 and 55' are in conductive contact with the metalized zones 51 and 51' of plates 49 and 50, respectively, which are engaged by proximal heads of rivets S2, 52' traversing the drum walls 53 and 54, respectively.
As illustrated in FIG. 4, however, it is also possible to use a separate stud 58 as an indexing member cooperating with the corrugations 56 of drum 37 and to provide an extension 59 of conductive zones 51 in contact with the end of post 55 which in this case will be flush with the inner surface of plate 49.
As illustrated in FIG. 3, the outer surface of drum 37 carries hour markings (here ranging from 00 to 23, in conformity with those of digit wheel 6) while drum 36 is similarly provided with minute markings (ranging from 00 to 59). It will be convenient, as shown, to write out only the even-numbered indications and to replace the odd-numbered ones by lines, dots or the like. These 24 scale divisions of drum 37 and 60 scale divisions of drum 36 can be observed through a viewing slot of the housing and/or read against an arrow or other marker alongside each drum showing the exact hour and minute to which the two drums have been set.
Two disks 38, 39 are sandwiched between the drums 36, 37 and are also freely rotatable on the axle 40. The two disks have identically shaped bodies of insulating cludes the rivet 52 so that the electric circuit from terminal 55 is extended to disk 39 whenever this disk and the drum 37 are in a predetermined relative position, i.e. the position in which the hour reading of the drum corresponds to that displayed by the digit carriers 8 etc. of wheel 6. In an analogous manner, disk 38 carries a contact spring 81 on its side facing the drum 36, the latter spring bearing upon the outer surface of drum wall 54 to make contact with the rivet 52' thereof in a relative position in which the minute reading of the drum corresponds to that displayed by the digit wheels 4 and 5. Rivet 52 and spring 79 are so dimensioned and positioned that their area of contact extends over less than and is limited to a single operating position of disk 39 for any indexed position of drum 37; in an analogous manner, the area of contact of rivet 52' and spring 81 extends over less than 6 and is also limited to a single operating position of disk 38 for any indexed position of drum 36. Disk 39 is further provided with a conductive annular track 83 continually wiped by a contact brush 80 on the inner surface of disk 38; with springs 80 and 81 conductively interconnected and with spring 79 also permanently connected to track 83, spring 79 lies always in circuit with spring 81 so that the load circuit 101 103 is completed whenever spring 79 contacts the rivet 52 at the'same time that the spring 81 engages the rivet 52.
The rivets 52 and 52' represent discontinuities in the insulation of their respective drums and, in a simplified system, may be replaced by openings in the drum wall through which the free ends of the contact springs 79 and 81 can reach the conductive zones 51 and 51',
respectively, whenever the disk position matches the I vantageous with low-voltage power supplies, yet the interposition of the rivets afiords greater precision.
The transmission linking digit wheels 4 and 6 with disks 38 and 39, respectively, includes a shaft 66 extending parallel to the wheel axis, this shaft being journaled in an upturned extension 68 of bracket 1 and in the mounting plate 33. A gear 67 on shaft 66 is in mesh with the toothed periphery 65 of wheel 6 while a pinion 69 on the other end of that shaft drives a gear 77 keyed, together with a pinion 78, on a sleeve 76 freely rotatable on another shaft 73 spanning the plates 33 and 34. A similar sleeve 70, freely rotatable on shaft 66, bears a gear 71 in mesh with the toothed periphery 64 of wheel 4 and terminates in a pinion 72 meshing with a gear 74 keyed to shaft 73. Disk 39 has a toothed periphery 62 in mesh with pinion 78 whereas disk 38 also has a toothed periphery 63 in mesh with a similar pinion 75 keyed to shaft 73. This gear train provides a stepdown ratio of 24 n (i.e. 3 z 1) for the torque transmission from wheel 6 to disk 39, the latter being thusstepped once per hour through an angle of 15, and provides a step-down ratio of 6 1 between wheel 4 and disk 38 whereby this disk is advanced every minute through an angle of 6. Thus, the load circuit of FIG. 3 is closed once per 24-hour period for exactly 1 minute; naturally, this load circuit may include a holding relay or other timing means for either foreshortening or extend ing the operating time of the alarm 102.
FIGS. 5 and 6 show a disk body 82 of dielectric material which can serve as a blank for either of the two contact carriers 38, 39. One side of the blank has an annular recess 84 which, in the case of disk 39 (see FIGS. 8 and 8a), accommodates a flat metal ring 83 (FIGS. 7 and 7a) forming the aforedescribed conductive track. Recess 84 is flanked by several pairs of throughgoing slots 85 accommodating lugs 86 integral with ring 83 which are bent over at the opposite side of the disk. Mounting holes 87 and 88, on a common radius, receive conductive rivets 92 which in the case of disk 39 serve to fasten the contact spring 87 to the disk and to establish a conductive connection with the ring 83 having bores 87 and 88' to receive these rivets. The ring also has a tongue 91 with a tip traversing one of two bores 92, symmetrically flanking the aforementioned radius, to make contact with an extension 79 of spring 79 for additional mechanical and galvanic coupling. In the case of disk 38 (FIGS. 9 and 9a) the rivets 92 hold the two contact springs 80 and 81 in posi' tion on opposite sides of the disk body 82 and interconnect them electrically; an additional electric connec tion can be formed by passing an extension 81' of spring 81 through one of the holes into contact with a similar extension of spring 80 to which it may be soldered.
The positive coupling of the digit wheels 4 and 6 with the disks 38 and 39, respectively, via transmission 66 79 translates any manual adjustment of these digit wheels into a corresponding displacement of the contact disk.
1. A timepiece comprising:
a set of operatively interconnected digit wheels including a first wheel provided with time indications of a relatively high denominational order and a second wheel provided with time indications of a relatively low denominational order;
drive means for rotating said first wheel at a relatively slow rate and said second wheel at a relatively fast rate;
a first contact carrier and a second contact carrier juxtaposed for independent rotation about a common axis;
transmission means positively linking said first and second contact carriers with said first and second wheels, respectively, for rotary entrainment thereby;
a first rotary selector and a second rotaryselector centered on said axis and confronting said first and second contact carriers, respectively, said selectors being independently settable to any one of a multiplicity of angular position;
retaining means for holding each of said selectors in a chosen angular position;
co-operating first contacts on said first contact carrier and said first selector making in a predetermined relative position thereof;
7 co-operating second contacts on said second contact carrier and said second selector making in a predetermined relative position thereof; conductor means maintaining a continuous conductive connection between the contacts on said contact carriers; and
a load circuit including a source of current and a controlled device connected across the contacts of said selectors for actuation of said device upon simultaneous making of said first and second contacts.
2. A timepiece as defined in claim 1 wherein said digit wheels are mounted alongside said selectors and contact carriers for rotation about said axis.
3. A timepiece as defined in claim 2 wherein said transmission means comprises shaft means parallel to said axis and gear means on said shaft means, said first and second wheels and said first and second contact carriers beingprovided with peripheral teeth meshing with said gear means.
4. A timepiece as defined in claim 3 wherein said shaft means comprises a first inner shaft in driving engagement with said first wheel, a first tubular outer shaft freely rotatable on said first inner shaft in driving engagement with said second wheel, a second inner shaft in driving engagement with said first outer shaft and with said second contact carrier, and a second tubular outer shaft freely rotatable on said second inner shaft and in driving engagement with said first inner shaft and with said first contact carrier.
5. A timepiece as defined in claim 1 wherein the time indications of said first wheel are hour markings and the time indications of said second wheel 'are the units digits of minutes, said digit wheels including a third wheel with time indications constituting the tens digits of minutes, said second wheel being rotatable by said drive means at a rate of one-tenth revolution per minute, said transmission means interconnecting said second wheel and said second contact carrier with a step-down ratio of 6:1 whereby said second contact carrier performs one revolution per hour.
6. A timepiece as defined in claim 5 wherein said first wheel is rotatable by said drive means at a rate of one revolution every n hours, said transmission means interconnecting said first wheel and said first contact carrier with a step-down ratio of 24m whereby said first contact carrier performs one revolution per 24-hour period.
7. A timepiece as defined in claim 6 wherein said first wheel is provided with n peripherally mounted rotatable bodies each having 24/n faces and bearing said hour markings, each of said bodies being provided with tripping means operative upon passage of said first wheel through a predetermined rotary position for displaying different faces during successive revolutions.
8. A timepiece as defined in claim 1 wherein said drive means comprises a stepping mechanism for intermittently advancing said first and second wheels through successive indicating positions corresponding to the multiplicity of angular positions of said first and second selector means, respectively, whereby said load circuit remains closed for a period equaling the re sidence time of said second wheel in any of its indicating positions.
9. A timepiece as defined in claim 8 wherein said residence time is ,one minutg.
10. A timepiece as de ned in claim 1 wherein each lating element on the side opposite said fixed element and bearing an axially projecting contact spring engaging said insulating element for galvanic contact with said face upon registering with said discontinuity.
11. A timepiece as defined in claim 10 wherein said fixed element is a resiliently deformable plate provided with an eccentric formation projecting toward said insulating element, the latter having a corrugated surface co-operating with said formation for indexing said insulting element in any selected angular position.
12. A timepiece as defined in claim 11 wherein said insulating element is generally cup-shaped and surrounds said plate.
13. A timepiece as defined in claim 12 wherein said insulating element has a toothed outer peripheral zone, further comprising a setting wheel for said insulating element with teeth engaging said peripheral zone.
14. A timepiece as defined in claim 11 wherein said formation is part of a terminal post connected to said load circuit.
15. A timepiece as defined in claim 10 wherein said discontinuity comprises a metallic rivet with a first head bearing upon said face and with a second head engageable by said contact spring.
16. A timepiece as defined in claim 10 wherein each of said contact carriers is a peripherally toothed disk of dielectric material provided with conductive facings on opposite surfaces and with throughgoing metallic connectors for said facings, said contact spring being part of one of said facings.
17. A timepiece as defined in claim 16 wherein both facings of one of said contact carriers form respective contact springs extending in opposite axial directions, the facing of the other of said contact carriers confront ing said one of said contact carriers being an annular track in constant engagement with one of the contact springs of the last-mentioned contact carrier.
18. A timepiece as defined in claim 17 wherein said other of said contact carriers is provided with an annular recess, said track being a metal ring lodged in said recess.
19. A timepiece as defined in claim 18 wherein said ring is provided with integral lugs, said other of said contact carriers having slots alongside said recess traversed by said lugs.
20. A timepiece as defined in claim 16 wherein said metallic connector is part of a tongue integral with said contact spring.
21. A timepiece as defined in claim 1 wherein said controlled device is an alarm-signal generator.
UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION v Patent No. 3, 35, 79 Dated 7 September 1972 Inventor(s) Gunter et 81 It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:
Page 1, in the heading prior to line -:l.nsert:
'"" 3] -9 1 Kundo Kieninger Obergfell',
I I Postfach, Geor'gen im Schw arzwald, Germany Signed and sealed this 8th day of May 1973 (SEAL) Attest:
EDWARD M. FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents "3 1 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent Nbv 3.686.879 Dated 1 September 1912 Inventofls) Gunter ml: at 8.1
It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:
Page 1, in the heading prim: to line insert:
7 r v 2. fi q ee: Kundo Kieninger Obergfell',
Postfach, Georgen im Schwarzwald, Germany Signed and sealed this 8th day of May 1973.
(SEAL) Attest: EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents