US1866406A - Electric switch - Google Patents

Description

July 5, 1932 R. c. GRASEBY ELECTRIC SWITCH Filed Aug. 26, 1929 2 Sheets-Sheet 1 :liliiii m. ilili July 5, 1932. R c GRASEBY 1,866,406

ELECTRIC SWITCH Filed Aug. 26, 1929 2 Sheets-Sheet 2 FIG. 5 A- OuTGome SIGNN.

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J lJ-x TIME. SWITCH FIG 4 Patented July 5, 1932 iinrrsn STATES PATENT OFFICE ROBERT CONSTANTINE GRASEBY, OF WESTMINSTER, LONDON, ENGLAND ELECTRIC SWITCH Application filed August 26, 1929, Serial No. 388,556, and in Great Britain September a9, 1928.

This invention has relation to electric switches and it has for its object to provide an electric switch to be used in the control of an electric circuit that is made and broken a number of times, the circuit being maintained operative for one or other of two periods of time which are not of the same duration, the consecutive functions of the circuit being of like or unlike durations.

In recent years a system has developed of direction-finding for ships by means of wireless signals from shore stations. It is customary with this system for a shore station to send out wireless signals by Morse code (longand-short or dot-and-dash current impulses) each signal representing an arbitary combination of letters, for example, A B; the combination used will be that most likely to be distinctive at the particular station. The current impulses representing this letter signal are sent out a plurality of times (for example 19) in rapid sequence, after which there is a long impulse (for example, of a length equivalent to the sending of four letter signals and for the purpose of description referred to hereinafter as four continuous signals), and then the letter signal is sent out once again; then the station closes down for an interval after which the whole succession of signals is repeated once again and so on.

If this system is to be developed to the ex tent desirable it will be necessary that provision shall be made for sending such signals from isolated spots upon the coastline and it 3 may be from islands at present uninhabited. Such development would, however, be costly if in these places it were necessary to employ continuously a staff of resident operators.

Thiswould be so especially in the case of ,40 those isolated stations which were not associated with other activities such as the activities of a normal wireless station or of a coastguard or lifeboat station.

It is an object of the present invention to provide for the automatic sending of a required succession of signals, and also for the automatic repetition of the succession at desired intervals. It is also an object of the invention to provide a reliable and comparatively cheap mechanism for sending the required signals, and one in which adjustment of the mechanism for a diflerent signal may be easily and quickly effected.

An electric'switch, in accordance with this invention, comprises a circuit breaking and maklng member proper, a pair'of cams of different lengths mounted thereon, a rotatable member mounted in relation to the circuit breaking and making member, and contacting members mounted on said rotatable member to co-operate with one or other of said cams.

One form of apparatus for sending out a definite succession of signals and embodying the features of the present invention will now be described with reference to the accomp anying drawings wherein Fig. 1 shows a. vertical elevation partly in section and with parts broken away,

Fig. 2 shows a plan view thereof,

Fig. 3 shows a section on the line 33 of Fig. 2 and in the direction of the arrows,

Fig. shows the electrical connections of the apparatus, and

V Fig. 5 shows a detail of the circuit making and breaking member with the cams mounted thereon.

1 is a casing having a platform 2 mid-way of its height so that the bottom part 3 constitutes a chamber to contain oil in which the driving gear runs. The signals are pro duced by a circuit making and breaking member which comprises a lever 4 under the action of a spring 5 or weight which tendsto hold it in a position in which the circuit controlled thereby is open. Mounted on the lever land at one end is a pair of cams 6, 7 which are disposed one above the other and which are of different lengths as indicated in Fig. 2 and Fig. 5. Adjacent to and about on a level with the lever 4: is a first horizontal disc 8 which has on its upper face a number of round contacts 9 which are all of the same size and which as the disc rotates strike the long cam 6 and move the lever 4 and hold it in its operative position until the contact 9 leaves the cam 6, that is, cause closing of the contacts 10, 10, theone carried on the lever 4L and the other on a spring 11; similarly the disc 8 carries on its lower face a number of similar contacts 9, whichco-operate similarly with the short cam 7 to close the contacts 10, 10. The contacts 9 are, preferably, removably mounted on the disc 8 to permit their number and spacing and thus the operation of the switch to be varied. Preferably the contacts 9 are, as indicated in Fig. 2, in the form of rollers carried by pins inserted in the disc 8.

The propelling motor 12 is mounted on the platform 2 and drives through worm gearing 13, horizontal shaft 14, and gearing 15, one of the sun wheels 16 of a differential gear. The disc 8 constitutes the body to be driven and is mounted above the platform 2 on a shaft 17 extending through the platform and carrying the planet wheels 18, 18 of the dif ferential gear. 19 is the secondsun wheel which carries on its upper face a series of pins 20. 21 is a second disc mounted on the shaft 17 above the sun wheel and having a pin 22 projecting downwardly therefrom. Mounted in relation to the second sun wheel 19 and the second disc 21 is asecond lever 23 fulcrumed at 24 on a bracket 25 depending from the platform 2. Said lever 23 carries at one end the armature 26 of an electromagnet 27 and at the other end is adapted to engage the pins 20 on the sun wheel 19 or move into the path of the pin 22 on the disc 21 according to whether the electro-magnet 27 is energized and its armature is attracted (against spring loading 24) or not. A relay 28 connected in parallel with the electromagnet 27 operates a switch 29 in the motor circuit and a second switch 30 is provided in the electro-magnet and relay circuit.

A disc 31 also mounted on the spindle 17 carries a pin 32 which engages a star wheel 33 having a number of arms equal to the number of signals of a succession to be sent out. For example, if the letters A B constitute a letter signal and are to be sent out 19 times followed by four continuous signals and then afinal letter signal, said star wheel will have 24 arms, the four continuous signals being counted together with the 20 letter signals. The star wheel 33 is carried on a spindle 34 rotatably mounted in the platform 2 and said spindle carries also two cams 35 and 36. The cam 35 actuates the lever 37 pivoted at 38 and carrying at its opposite end a contact of the switch 30. A spring 39 tends to hold said switch open. A projection 40 carried on the lever 4 below the cams 6 and 7 projects into the path of the cam 36.

A time switch indicated at 41 in Fig. 4 is connected across the switch 30 in the circuit of the electro-magnet 27 and the relay 28 to of the pin 22 on the second disc 21 into engagement with the pins 20 on the second sun wheel 19 thereby locking the latter. The relay 28 is also energized and closes the switch 29 in the motor circuit thus causing the motor to start. The first disc 8 is thus rotated and its pins or contacts 9 engage the cams 6 and 7 and cause the lever 4 to close the switch 10 to send out the required impulses. The disc 8 rotates the required number of times, in the instance suggested above 19 times,'when the cam 36 which has been rotated through engagement of the pin 32 on the disc 31 with the star wheel 33, engages the part 40 of the lever 4 and holds the latter in a position to cause the contacts 10 to send out a continuous impuse for the next four revolutions of the disc 8. The cam 36 has then reached such a position that the lever 4 is released so that it can be again actuated during the final revolution of the first disc 8 to send out the final signal.

The second cam 35 on the star wheel spindle 34 operates after a few revolutions of the first disc 8 to close the switch 30 by acting on the end of the lever 37, and thus allows the time switch 41 to be set to open circuit at any instant short of the run of the apparatus. When the star wheel 33 has completed one revolution, that is, when the required succession of signals have been sent out the cam 35 operates to allow the switch 30 in the circuits of the electro-magnet 27 and relay 28 to open and the apparatus is then stopped.

The pin 22 carried on the disc 21 is in such a position that when the switch 30 is opened at the end of the succession of signals said pin is close to the second lever 23 carrying the armature 26 of the electro-magnet 27. As the electro-magnet is de-energized said arm moves into the path of the pin 22 and the latter is carried up to it by the overrunning of the differential. The apparatus is thus stopped in a position in which it will always commence sending its signals at the same point in the succession.

It is to be observed that not only can the contact members 9 be altered as to number and position but by unscrewing the knurled nut shown in Figure 1 above the disc 8 the disc may be removed bodily and another disc with contact members 9 spaced to give a different letter signal may be readily substituted.

What I claimis 1. An electric circuit make-and-break device adapted to produce dot-and-dash signals comprising a pair of electric contacts, means to close the said contacts, the said means including a long cam and a short cam, a disc pivotally mounted adjacent to the cams with its periphery close to but spaced from them, contacting members all of similar shape mounted at predetermined intervals upon opposite sides of the disc, therelationship of the contacting members and the cams being such that on rotation of the disc all those contacting members on one side of the disc will in turn contact with the long cam to produce dash signals, and those contacting members on the other side of the disc will in turn contact with the short cam to produce dot signals, and means to rotate the disc.

2. An electric circuit make-and-break device adapted to produce dot-and-dash signals comprising a pair of electric contacts, a rock- 'ing lever carrying one of the said contacts,

a spring acting normally to cause separation of the contacts, a long cam carried by the lever, a short cam carried by the lever and spaced from the long cam, a disc pivotally mounted adjacent to the lever with its periphery close to but spaced from the cams. contacting members all of similar shape mounted at predetermined and adjustable intervals upon opposite sides of the disc and overlapping the periphery thereof so that on rotation of the disc all those contacting members on one side of the disc will in turn contact with the long cam to produce dash signals, and those contacting members on the other side of the disc will in turn contact with the short cam to produce dot signals, and means to rotate the disc.

3. An electric circuit make-and-break device adapted to produce dot-and-dash signals comprising apair of electric contacts, a horizontal rocking lever carrying one of the said contacts, a spring acting normally to cause separation of the contacts, along cam carried by the lever, a short cam carried by the lever and spaced from the long cam, a horizontal disc pivotally mounted adjacent to the lever with its periphery close to but spaced from the cams, contacting members all of similar shape mounted at predetermined and adjustable intervals upon opposite sides of the disc and overlapping the periphery thereof so that on rotation of the disc all those contacting members on the upper side of the disc will in turn contact with the long cam toproduce dash signals and those on the under side of the disc will in turn contact with the short cam to produce dot signals, a second disc coaxial with the first disc and rotated therewith, a pin upon the second disc adapted upon each rotation of the said second disc to engage with a star wheel and move it one tooth, the said star wheel being pivoted upon a pivot parallel with the pivot of the discs, a cam connected to the star wheel for rotation therewith, a depending projection from the rocking lever adapted to be moved by the cam so as to cause the rocking lever to close the contacts to produce a long signal during at least one complete revolution of the first disc whereby during such revolution the first disc becomes ineffective to produce dot-and-dash signals, and means to rotate the discs.

4. An electric circuit make-and-break-device adapted to produce dot-and-dash signals comprising a pair of electric contacts, means to close the said contacts, the said means including a long cam and a short cam, a disc pivotally mounted adjacentto the cams with its periphery close to but spaced Dated this 15th day of August, 1929.

' ROBERT CONSTANTINE GRASEBY.

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