US2487573A

US2487573A - Switch contact

Info

Publication number: US2487573A
Application number: US673006A
Authority: US
Inventors: Meier Hans
Original assignee: Landis and Gyr AG
Current assignee: Landis and Gyr AG
Priority date: 1945-06-26
Filing date: 1946-05-29
Publication date: 1949-11-08
Anticipated expiration: 1966-11-08

Description

H. MEIER SWITCH CONTACT Nov. 8, 3949 Filed May 29, 1946 Patented Nov. 8, i949 SWITCH CONTACT Hans Meier, Zug, Switzerland, assignor to Landis & Gyr, A. G., a corporate body of Switzerland Application May 29, 1946, Serial No. 673,006 In Switzerland June 26, 1945 (Cl. 20G-33) 6 Claims. l

The present invention relates to a maximum contactor for time switches, the usual use of the contactor being its connection through a relay with a maximum indicating meter or a maximum recorder.

Objects and advantages of the invention will be set forth in part hereinafter and in part will be obvious herefrom, or may be learned by practice with the invention, the same being realized and attained by means of the instrumentalities and combinations pointed out in the appended claims.

The invention consists in the novel parts, constructions, arrangements, combinations, and improvements herein shown and described.

The accompanying drawings, referred to herein and constituting a part hereof, illustrate one embodiment of the invention, and together with the description, serve to explain the principles of the invention.

The present invention has for an object the provision of an improved maximum contactor which is compact in construction and which actuates the contacts in a time which is completely independent of the length of the recording period for the maximum indicating meter or maximum recorder, Another object of the invention is the provision of a maximum contactor of the above characteristics which may be simply adjusted for different recording periods without the exchange of a large number of the essential elements thereof.

The drawing is a, perspective view, in part schematic, of a typical and illustrative embodim'ent of the invention.

Apparatus with which the present invention is adapted to be used, that is, maximum indicating meters or maximum recorders, may require an open circuit contactor. In this type of apparatus the maximum contactor must break a circuit for a short time periodically. With other embodiments of maximum apparatus closed circuit contactors are used in which the contactor is closed for a short time to transmit a periodic current impulse at the end of a recording period. In the operation of conventional maximum contactors a mechanical or electrical timing mechanism acts through suitable transmission means to actuate a cam on which slide two contact arms with slightly offset terminal edges, forming a contactor which is actuated for a short time at the close of each recording period. During this actuation of the contacts a maximum device in the maximum apparatus is returned to its neutral position. This normally takes about a second. As

2 a rule a recording period is 5, 10, 15, or 60 minutes, and is set by interchangeable transmission means for the contactor.

A principal difficulty with conventional contactors is that the period of actuation thereof varies with the length of the recording periods, and, also, a number of different pinions must be kept on hand for the interchangeable transmission mechanism. Moreover, reliable control of the relay current is very difficult, since the cam controlling the maximum contactor moves at a relatively low speed.

Some improvements have been introduced to enable the actuation period of a maximum contactor to be kept constant and independent of the recording period, but these have required bulky mechanical parts, such as scissors levers, for instance, they are dicult to adjust, and they require changes in transmission gearing for different recording periods.

These defects are remedied in accordance with the present invention by providing a contactor which is compact, which allows the change of the recording period by the exchange of a single,

easily accessible part, leaving the transmission gearing as a permanent part, and in which the actuation period is independent of the recording period.

Referring now in detail to the illustrative em'- bodiment of the invention shown by way of example in the accompanying drawing the reference numeral I' designates the hour shaft of any suitable timing mechanism (not shown). The shaft I carries a gear wheel 2 xed thereto which drives a gear 5 freely mounted on the shaft through gear wheels 3 and Il. The gearing 2, 3, 4 and 5 provides a transmission having a fixed velocity ratio for all recording periods of the contactor.

A two armed lifting lever 6 is lixed to gear 5 for rotation therewith, and after each halfrevolution of the lever one arm contacts a pin 'I extending outwardly from a release lever l0. The lever I0 is pivoted about a shaft 8 and is spring biased toward the lever 6 by a spring 9. The upper end of release lever I0 has an enlarged head Il having an upper surface to support the two contact arms I2 and I3 of a maximum contactor. The contacts I4 and I5 of arms I2 and I3 respectively are closed in normal position as shown in the drawing. The arrangement of a maximum contactor which is open in the normal position is represented by a contact arm 22 actuated from arm I3 by an insulated push rod 25 passing through arm I2 and engaging the under surface of arm 22. The contacts 23 and 24 then provide a contactor of the normally open type. It will fully be understood by those skilled in the art that a contactor may comprise both types of contacts as show n in the drawing, or only one, either one being chosen as desired and the other left out of the construction.

On the left end of spindle I as seen in the accompanying -drawing there is xedly but removably mounted an interchangeable cam plate I6 provided with a number of radially extending arms. The number of arms will vary with the duration of the recording period which is desired. A triangular lever 20, adapted to pivot :about la shaft I8, has a laterally extending pin -II to be engaged successively by the arms `of cam :plate I6, the lever 20 being thereby rotated in a counterclockwise direction. Lever 20 is biased by a spring I9 in the opposite direction toward 'the arms of cam plate I6. When lever 20 is rotated by plate I6, a pin 2| extending laterally from the lever engages under arms I2 and I3 and raises them to a position such that release lever IU can swing its head II under the ends of the contact arms and support them.

The transmission gearing 2, 3, 4, 5 causes the lever 6 to rotate through a complete revolution in a iixed period of time say, for example, l minutes. Thus, at the end of every five minutes one of the ends of the lever encounters the pin I and swings the release lever Ill out of the contact arm supporting position, allowing arms I3 and 22 to drop simultaneously, and contact arm I2 a little later. In order to effect this timed dropping of the contact arms the front edge of arm I3 is cut back to a slight extent from parallelism with the front edge of arm I2, so that arm I3 will drop olf of head II rst. In an illustrative embodiment of the invention shown the length of arm I3 may be about 0.4 mm. less than the length of arm I2, which corresponds in point of time to about one second between the falling of the arms.

The fall of the shorter arm I3 separates contacts I4, I5 and closes contacts 23, 24. The subsequent fall of the longer contact arm I2 restores the original condition of the contacts, that is, I4, I5 closed and 23, 24 opened. The arms I2 and I3 are not restored, for further contact actuation, to a position on the top surface of head Il of lever Ill until an arm of cam plate I6 engages and rotates triangular lever 20, the latter governing the length of the recording period. It may therefore be seen that the time elapsed in actuating the contacts is always the same irrespective of the length of the recording period.

The cam plate I6 controlling lever 2U maybe provided with a number of arms which will depend upon the lengthrof the recording period desired. For example, in the case of the periods hereinbefor'e enumerated, namely 60, 30, 15, 10 and 5 minutes, the cam IB will have l, 2, 4, 6 and 12 arms respectively. When one of these arms contacts pin II on lever 20, the contact arms I2, I3 and 22 are lifted into a position in which release lever Ill may lbe spring moved to support them as shown in the drawing, and the contacts are in condition for actuation when an arm of lever 6 next engages release lever Ill.

It will be apparent from the construction shown and described that the mechanism is compact, there is only one xed transmission, and the time occupied in actuating the maximum contactor is entirely independent of the recording period. Moreover, the length of the'recording period may be kchanged simply by exchanging a simple cam plate I6, so that, apart from this member, the fully assembled contactor may always be kept in stock.

The invention in its broader aspects is not limited to the specific mechanisms shown and described but departures may be made therefrom within the scope of the accompanying claims without departing from the principles of the invention and without sacrificing its chief advantages.

What I claim is:

l. Alswitch to be actuated from a continuously rotating shaft comprising, in combination, a pair of switch -arms supported by a pivotal lever in an original position, said arms and lever being so formed that upon pivoting the lever one arm falls .free of the lever before the other arm falls free, said arms assuming an actuated position upon falling free of the lever, means interconnecting the shaft and said lever for periodically pivoting the lever, means for returning the lever, Sand means interconnecting the shaft 'and said arms for periodically returning said arms from actuated to original position, 'said lever being inoperative to support said arms while said arms are in an actuated position.

2. A switch to be 4'actuated from a continuously rotating shaft comprising, in combination, a pair of switch arms supported by a pivotal lever in an original position, said arms and lever being so formed that upon pivoting the lever one arm falls free of the lever before the other arm falls free, said arms assuming an actuated position upon falling free of the lever, means interconnecting the shaft and said lever for periodicallt7 pivoting the lever, means lfor returning the lever, and means interconnecting the shaft and said arms for periodically returning said arms from actuated to original position, said means comprising a removable cam on said shaft, said lever being inoperative to support said arms while said arms are in an actuated position.

3. A switch to be actuated from a continuously rotating shaft comprising, in combination, a pair of switch arms supported by a pivotal lever in an original position, said arms and lever` being so formed that upon pivoting the lever one arm falls free of the lever before 'the other arm falls free, said arms assuming an actuated position upon falling free of the lever, ,means interconnecting the lshaft and said lever for periodically pivoting the lever, means for returning the lever, and means interconnecting 'the shaft and said arms for periodically returning said arms from actuated to original position, said means comprising a removable cam on said shaft and a pivotal member engageable lby said cam to be pivoted to engage said arms, said lever being inoperative to support vsaid arms while said arms arein an actuated position.

4. A-switch to be actuated from a continuously rotating shaft comprising, in combination, a pair o'f switch arms supported by a 'pivotal lever in an original position, said arms and lever `being so formed that upon pivoting the lever one arm falls free of the lever before the other arm falls free, said varms assuming .an actuated position upon falling vfree 'of the lever, means interconnecting the shaft and said .lever for periodically pivoting the lever, said means comprising a cam and fixed ratio gearing between the shaft and said cam, means for returning the lever, and means interconnecting rthe `shaft and said arms for periodically returning ysaid arms from actuated to .original position, said lever being inoperative to support said arms while said arms are in an actuated position.

5. A switch to be actuated from a continuously rotating shaft comprising, in combination, a pair of switch arms supported by a pivotal lever in an original position, said arms and lever being so formed that upon pivoting the lever one arm falls free of the lever before the other arm falls free, said arms assuming an actuated position upon falling free of the lever, means interconnecti-ng the shaft and said lever for periodically pivoting the lever7 said means comprising a cam to engage and pivot said lever and xed ratio gearing between the shaft and said cam, means for returning the lever, and means interconnecting the shaft and said arms for periodically returning said arms from actuated to original position, said lever being inoperative to support said arms While said arms are in an actuated position.

6. A switch to be actuated from a continuously rotating shaft comprising, in combination, a pair of switch arms having parallel ends supported by a pivotal lever in an original position, said lever ends terminating at diierent positions with respect to said lever so that upon pivoting the lever one arm may fall free of the lever before the other arm falls free, said arms assuming an actuated position upon falling free of the lever, means interconnecting the shaft and said lever for periodically pivoting the lever, means for returning the lever, and means interconnecting the shaft and said arms for periodically returning said arms from actuated to original position, said lever being inoperative to support said arms while said arms are in an actuated position. HANS REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 2,124,045 Swensen July 19, 1938 2,128,357 Friden Aug. 30, 1938