US3192330A - Electrically driven time switch mechanism - Google Patents

Description

June 29, 1965 w. HOLZER ELECTRICALLY DRIVEN TIME SWITCH MECHANISM Filed Nov. 21, 1962 F1g.1. 3a 39 l I lNVENTORi WALTER HoLzgR' June 29, 1965 w. HOLZER 3,192,330

ELECTRICALLY DRIVEN TIME SWITCH MECHANISM Filed Nov. 21, 1962 2 Sheets-Sheet 2 "Illlll IN VE N TO R WALTER HOLZER BYWQCMM/ Attorney5 United States Patent 6 Claims. (21. 200 ss The invention relates to electrically driven time switches.

The invention aims to provide a time switch which can be made economically and needs little adjustment in use and particularly, through appropriate use of contacts and an appropriate contact pressure, enables large loads to be controlled without the need for intermediate relays.

In previously proposed time switches having an electric motor drive, adjustable on and oil? periods and an indication of the values set, the switching contacts are biased and are operated from a switching disc. This disc has raised portions which operate the contacts during the passage of a release mechanism. The disadvantage of such constructions is that it is'not possible to use contacts as large as may be desired and having a switching pressure of desired strength, since the release mechanism would not operate satisfactorily and a drive motor of considerable size would be required. The resultant enlarged construction and increased manufacturing cost are disadvantages which the time switch of the present invention seeks to avoid.

According to the. invention, a time switch is provided which is to be driven by an electric motor and in which the drive motor for the time switch also drives a cam which performs the switching operation, the cam being driven through gearing which is not used for timing and which can be released from the drive.

The gearing is preferably released by means of a clutch.

In this construction the release mechanism is no longer actuated by the passage of an entrainment pin, but instead, a direct gearing is provided such as is otherwise used for switching large loads. The force with which the gearing is driven in order to operate contacts of a desired size for loads of any desired size is merely a question of providing suflicient reduction. The construction is simplified in that, during the switching operation, the same motor that drives the time mechanism also actuates the gearing oi the cam.

It is desirable for manually adjustable components to form stationary abutments located in the region of a lever which is driven by the time mechanism and scans the abutments.

It is sutlicient for the components, for example to move a lever upwards and downwards, so as to operate a clutch which couples the drive motor of the time mechanism to the drive for the cam or releases it therefrom.

it is preferable that the components are in the form of at least two mutually adjustable discs which determine and indicate the point and duration of switching and have gliding paths of different heights which are scanned by a lever moved by the time mechanism, the lever producing the power linkage, through a gearing and a clutch arrangement, between the drive motor and the drive of a cam for operating the switching contacts.

The construction is simplified if the discs indicating the state of switching also have the gliding paths arranged on them. the drive motor to the drive for the cam, then friction wheels can be used for this purpose. It is equally possible, however, to produce the connection by means of a positive connection. With such a construction, the coupling between the time mechanism and the drive for the cam is formed by a gear which is positively connected to the If the power connection is used to connect Patented June 29, H965 indicator spindle and is also capable of being axially displaced thereon by the lever scanning the gliding path.

In order to prevent switching from taking place when the switching positions are rapidly passed through in adjusting the switching times, it is essential for the cam to be spaced from the contacts in the rest position, for example, with the cam bearing on an abutment, so that when the cam moves, contact-making is delayed.

If the cam has to cover a certain distance before it performs the switching operation, then it is not possible for switching to be eifected merely on rapid turning through the switching position. The idling which to a certain extent takes place between the movement of the cam and the contact-making can be obtained, for example,

by means of a spiral spring one end of which is fastened to the rotary spindle of the cam and the other end, is fastened to the housing, so that the cam tensions the spiral spring as it is moved away from the abutment against which it rests in the rest position.

The cam accordingly has a defined starting position determined by a spiral spring. It is important for the cam to be driven through a slip coupling, the rotary movement of the cam being limited by another abutment when the cam operates the contacts.

To make contact at stationary contacts, the cam is moved against the tension of the spiral spring until it closes the contacts. The cam, however, continues to be driven during the whole of the switching time. A slip clutch and an abutment hold the cam to the contacts so that the latter remain closed. If the drive motor clutch, which is operated by the scanning levers, is released, then the cam springs back into its starting position by the action of the tensioned spiral spring, and from this position again performs the delayed switching operation.

There is a wide variety of possible constructions for the circular gliding path. One is for the discs to have arcuate gliding paths of different length and height, so that the lever scanning the gliding path couples the cam drive to the time mechanism or releases it therefrom according to the height of the gliding levers scanned.

it is desirable for the gliding paths to have sloped portions if the scanning lever is led from a lower level to the higher one. The advantage of this construction is that the drive motor is not abruptly loaded and it is consequently possible to operate the time switch and obtain large switching performances with relatively small synchronous motors.

Again there are many possible ways of moving the discs. In a preferred construction, one of the discs has an entrainment member which carries along another disc when the first disc is moved in one or other rotary directions by means of an adjustment knob.

This embodiment is structurally simple. Of course it is also possible to provide an adjustment knob for each of the discs. With this embodiment, however, it is sufli cient if when one disc is moved in one direction it carries along the other disc in the same direction by means of the entrainment member and is then turned back to take'up a different position. If such discs are used the switching-on and switching-off times, the duration of switching-on and the present state of switching can also be indicated in a clear, simple form. Among the many possibilities, a particularly simple one is for the discs to have holes at an equal spacing from the rotary spindle, which are superimposed according to the switching position and thus when they overlap allow a stationary disc below, which is preferably of a dilferent colour or luminous, to be seen.

With this construction one can see at a glance the time adjusted and the duration of the connection if the disc below is marked to show this. However, a third, stationary disc can be dispensed with if the top disc is pro- 3 vided with a hole and the disc below it is opaque and bears markings.

If an indication is to given of the state of switching, i.e. of the time left after switching on until switching off takes place, then it is important for the lever which is moved by the time mechanism and which actuates the clutch, to have an entrainment member. This member, as it slides down onto the'sector of the disc without a gliding path, entrains a disc which in a continuation of the movement closes the adjustment range, visibly demarcated by holes in the disc, the lever and thus the entrainment of the first disc being raised when the gliding path of the other disc reaches the switching-d point, and the adjustment range thereby being cancelled.

In this construction there are two entrainment members. One connects the two discs when one of the discs is moved by the manually operated adjustment knob during setting. The other entrainment member is fixed to the lever turned by the spindle of the time mechanism and now entrains the disc performing the switching-on operation, so that the sector which is visible in the hole and shows the switching time is constantly diminished until, when switching off takes place, the raised lever releases the cam clutch and thus simultaneously removes the entrainment member from the switching-on disc. There are many other possible ways of varying the total duration of the connection. For example, the discs could be moved more slowly than the hour hand, by means of an intermediate gearing, thus lengthening the connection time. Here the scanning lever is moved not by the rotary spindle of the hour hand but through an intermediate gearing by a slowly rotating wheel. It is also possible to provide an additional hand-operated switch to close or bridge the contacts.

Such an arrangement enables the switching process to be influenced at any time by intervening from outside in the cam drive, thereby to act on the contacts.

An example of the invention will now be described with reference to the accompanying drawing, in which:

FIG. 1- is a diagrammatic front elevation of a time switch;

FIG. 2 is a section taken along the line II-II in FIG. 1 shown in plan. The drawing is diagrammatic and the portions cut are not shaded, and

FIG. 3' is a diagrammatic plan view of the dial with the hand in a different position from that shown in FIG. 2.

In FIG. 1 the drive motor 1, which may, for example, be a synchronous motor, drives the rotary spindle 11 of the minute hand 16 through gears 2 to and the hollow shaft 14 for the hour hand 15 through gears 2 to 7, 12, 13. The hour hand 15 and the minute hand 16 are protected from mechanical damage by a transparent cover 17. The gear 13 is fixed to a bushing 18 having a peripheral groove 19, and is axially displaceable on the hollow shaft 14 against the spring 20, for example by means of a key. The bushing 18 is non-rotatably mounted on the shaft 14. The groove 19 is engaged by one end 21 of the lever 22, of which the other end 23 lies on the gliding path 24 of a disc 29. The lever 22 is mounted at the fixed fulcrum 25, which is arranged on a disc 26, the disc 26 being fixedly connected-to the hollow shaft 14. Another bushing 27, wh-ichcan rotate freely on the shaft 14, serves as a rotary bearing for the discs 28, 29. The disc 29 has an external toothed rim 30 which meshes with the pinion 31. The pinion 31 is fixed to the rotary spindle 32 and adjustment knob 33. In the position shown in FIG. 1, the end 23 of thelever 22 lies on the gliding path 24 of the disc 29 and thus the gear 13 is disengaged from the pinion 34; The pinion 34 and gears 35, 36 serve to drive the cam 37 which closes the contacts 38, 39 on being rotated. A spiral spring 40 is fixed at one end to the cam 37 and at the other end to the housing, for example, to one of the plates 41. An abutment pin 42 limits the rotary movement caused by the spiral spring 40 and determines the rest position of the cam 37. The rest position is the position l. of the cam 37 when the contacts 38, 39 are open. A slip clutch 43 is also arranged between the gears 35, 36.

FIG. 1 shows that the disc 28 also has a gliding path 44.

It will be seen from FIG. 2 that the gliding paths 24, 44 are arranged to overlap each other and that the disc 28 also has an arcuate slot 45 which is engaged by the entrainment member 46 fixed to the disc 29. If the disc 29 is turned in the direction indicated by the arrow 47 by means of the adjustment knob 33 and the pinion 3l, then in the position shown, the two discs 28, 29 are simultaneously turned in this direction by the entrainment member 46. If the disc 29 is rotated in the opposite direction, however, idling takes place until the entrainment member 46 reaches the other end of 'the slot 45, after which both discs 28, 29 are again turned in a direction contrary to that indicated by the arrow 47.

The discs 28, 29 have holes 48 arranged at an equal spacing from the bushing 27 forming the rotary shaft. In FIG. 2 the part of the holes 28 shown in full lines is aligned and would expose to view an inscribed disc (not shown) lying below it or above it in FIG. 1. FIG. 3 shows a dial 49 which is mounted between the cover 17 and the discs 28, 29 (see FIG. 1). The disc 28 also carries an arrow 50 serving as an index mark to show the switching-on time. The switch functions as follows. If the adjustment knob 33 is turned in one or other of the directions indicated by the arrows 51 and 52, then the gliding paths 24, 44 are turned towards one another by the entrainment member 46 in the slot 45. It is then possible to have a sector without any gliding path between the beginning and the end of the gliding path 24, if the path 44 extends over a region parallel to the path 24. When the end 23 of the lever 22 reaches such a portion without any gliding path, then the bushing 18 is moved in the direction 53 by the action of the spring 20. The drive motor 1 then drives the cam 37, once the gear 13 and pinion 34 have been engaged. If the engagement is immediately released, then the cam 37 has only covered a short distance and the contacts 38, 39 arenot closed. Over a long period of engagement between the gear 13 and the pinion 34, however, the cam 37 closes the contacts 38, 39. So long as the engagement between the members 13 and 34 is not released, the slip clutch 43 keeps the contacts 38, 339 closed against the action of the spring 40 and the drive motor 1 suffers no great obstruction despite the fact that the cam 37 is stationary. If the end 23 of the lever22 is lifted, for example, over an inclined surface at the beginning of the gliding path 24, into the position shown in FIG. 1, the bushing 18, which forms a coupling together with the spring 20 and gear 13, is moved contrary to the direction indicated by the arrow 53, so that the engagement between the gear 13 and the pinion 34 is. released. The spiral spring 40 is tensioned when the contacts 38, 39 are closed by the cam 37 and returns the cam to the abutment pin 42, so that the initial position of the cam and the contacts 38, 39 is regained.

The invention can be applied to all cases where there is a need for quick and cheap production of time switches which can overcome large switching loads with only a small drive load.

I claim:

1. An electrically driven time switch mechanism comprising a hollow shaft carrying a minute hand; an electric motor driving said shaft and including a slidably mounted gear on said shaft driven by said motor; said mechanism including a cam operated switch, a second gear driving said cam; said first gear being spring actuated to slide from non-meshing position to meshing position with said second gear; lever means, secured to said hollow shaft and rotating therewith, controlling the position of said 2. The invention defined in claim 1 wherein said slidably mounted gear has a bushing with a peripherical groove therein, and one end of the operating lever being received therein.

3. The invention defined in claim 1 wherein said lever means includes a lever which extends radially of said hollow shaft, a disc secured to and rotating with said hollow shaft, and said lever being pivotally mounted on said disc for rocking movement.

4. The invention defined in claim 3 wherein a peripherically grooved bushing is carried by said slidably mounted gear, and wherein the inner end of said lever rests in said groove, camming discs journaled on said hollow shaft below said secured disc and having outer edge portions camming the outer end portion of the lever upwardly thereby rocking the inner end of the lever downwardly and forcing the slidable gear downwardly against the spring action and into non-meshing position with the cam operated switch gear.

References Cited by the Examiner UNITED STATES PATENTS 2,858,388 10/58 Eastman 20038 2,995,916 8/61 SissOn 200'38 3,014,375 12/61 Bowen 200-33 BERNARD A. GILHEANY, Primary Examiner.

Claims (1)

1. AN ELECTRICALLY DRIVEN TIME SWITCH MECHANISM COMPRISING A HOLLOW SHAFT CARRYING A MINUTE HAND; AN ELECTRIC MOTOR DRIVING SAID SHAFT AND INCLUDING A SLIDABLY MOUNTED GEAR ON SAID SHAFT DRIVEN BY SAID MOTOR; SAID MECHANISM INCLUDING A CAM OPERATED SWITCH, A SECOND GEAR DRIVING SAID CAM; SAID FIRST GEAR BRING SPRING ACTUATED TO SLIDE FROM NON-MESHING POSITION TO MESHING POSITION WITH SAID SECOND GEAR; LEVER MEANS, SECURED TO SAID HOLLOW SHAFT

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