US1895350A - Time switch - Google Patents

Description

C. SNAY TIME SWITCH Jan. 24, 1933.

Filed Feb. l3, 1932 Patented Jan. 24, 1933 CARL SNAY, OF BEBLIN-SCHMABJGENDORF, GERMANY TIME SWITCH Application filed February 13, 1932, Serial No. 592,785, and in Germany March 25, 1931.

My invention .relates to electric time switches. Time switches are known in which the disconnection of the contact pieces is effected automatically after a certain lapse of time by means of a sand glass or similar means, such as a glass tube with a lead plunger fitting and slowly sinking down therein and retarded by a liquid contained in the glass tube. In one type of switch of this class the sand glass or the like is mounted .points and contact members are provided thereon.

Although this known principle seems to be verysimple, the switches based thereupon have not been improved in accordance with the requirements of modern heavy current engineerin more particularly hand switches suited or general public use. As in the switches of this class hitherto known the actuating member lies open for further manipulation from the moment of switching on to switching olf, there is the danger of disturbances occurring by inadvertence or tampering. Such disturbances are possible according to the construction of the actuat- 5 ing lever either by back turning or premature tilting motions or false setting of the points of actuation relatively toone another.

My present invention has for its object a time switch of the type described in which the drawbacks enumerated are overcome, this object primarily being obtained by an actuating lever or handle which can be moved only in an exactly prescribed path and wh ch is protected automatically from. any abusive manipulation.

As to the avoidance of undeslred sparks in these tilting switches, the deslgns hitherto known, as far as heavy current is concerned, are governed by the idea that very powerful contact springs have to be applied, as usual and required in hand switches for lighting purposes. When applying such powerful springs the volume of the tilting member has to be increased, to overcome the strong breaking eiiect of the springs, but this is posslble inpractice only in very narrow limits. Other remedies, such as simple openmercury contacts, give no satisfactory results.

Now I have found that neither extraordinarily powerful contact elements are .required nor liquid contact members, but that is only necessary to take care in theactuating movement and in the automatic tilting movement of a suitable acceleration and a uniform course of the contactmaking and breaking operation. This is obtained according to my invention by the peculiar construction of a small contact lever which is opposite to and cooperates with, the tilting member and acts as sliding contact and is disposed behind a flat insulating piece tangentially to a contact piece mounted on the tilting'member. This contact lever supports the tilting member as long as it has overweight and releases it in the tilting motion only when both these members, viz. the contact lever and the tilting member have reached their greatest possible acceleration. In closing the circuit, a separate spring serves to accelerate the movement while in opening the contacts the accelerated movement of the tilting member is used which it reaches only some time after the action of a counterweight has been overcome. Furthermore, a new and important effect is obtained in my new time switch in so far as there is a certain vertex point in the cooperation of the contact lever and the tilting member from which point the latter is urged additionally into its rocking motion, whereby a shockless closing and a particularly sudden breakage of the contact is obtained by extremely simple means.

While I prefer to employ a yieldable pivoted member for the contact lever, it is possible to carry out the invention in a some- .what less satisfactory manner by the use of a leaf spring of similar shape. The disadf vantage of the leaf spring is that it loses its 1 0 spring power in course of time and, in the case of small switches, is difficult to reset.

The new time switch will now be fully described as to its construction and mode of operation, more particularly the actuating handle and the contact lever, with reference to the accompanying drawing which illustrate by way of example a preferred embodiment of my new switch. The switch illustrated is more particularly adapted for temporarily lighting of passages, stair cases or the like, but may be used also for permanent lighting by adding a simple locking device, as hereinafter pointed out.

In the accompanying drawing Figure 1 is. a front view of a switch de signed according to my invention, the front wall of the casing being thought broken away in the center,

Figure 2 is a rear view thereof, the rear casing wall being removed,

Figure 3 is a vertical sectional view and Figure 4 a horizontal section thereof.

Figure 5 is a detail showing the abovementioned contact lever on an enlarged scale, while Figure 6 illustrates, by a view similar to Figure 1, the application of the above-mentioned locking device serving to obtain permanent closure of the circuit.

In Figures 1 and 2 is represented the circuit-closing position of the parts under consideration, while in Figures 3 and 4 they are in off position.

As will be seen from Figures 1 and 2, the journal of the tilting member A has a diametrical bore in which a handle (I forming the actuating member is adapted to glide freely like the handle of a vise. The handle (Z serves to turn the tilting member A to operative position which member may consist of 'a sand glass or any suitable equivalent device. As will be seen from Figure 2, the tilting member carries two diametrically opposite contact pins 0, c. In the position of rest ofmember A the lower part of the handle d is situated in the range of an open window 27 provided in the front wall of the casing and having a shape so as to admit movement of the handle d only in a clockwise upward direction by one finger, as indicated by an arrow, Figure 1. A guide face g, Figure 1, for the rear end of handle 03 and a spring f, see also Figure 4, serve to secure this prescribed movement of handle d which thus cannot deviate from its path and, finally comes to abut, after having passed along spring f and been accelerated by the latter, against a fixed stop a, Figure 1, suitably mounted in a small recess of the casing. As the handle (Z, after having reached this position is only still in loose touch with the finger and-cannot be seized otherwise, any backward movement by hand is impossible. The handle 01 reaches the stop a after a rotation of about 150. Shortly before, about at 140, the circuit is closed by the respective contact pin 0 of the tilting member A and the contact lever 6, see Figure 2. When reaching stop a, the handle (5 thus has already accomplished its object and is then released and slides down to a position marked in dotted lines in Figure 1. At the same time the tilting member which still has overweight, slightly rocks back and the pin 0 comes to abut against an insulating piece e fixed to contact lever b. By this back motion the handle d is slightly lifted from stop a so as to drop securely, and then remains in the obturated position marked in dotted lines in Figure 1. In this position the handle is not accessible; it leaves this position and advances to a new ready position in the range of window 71 only at the end of the tilting motion of member A. I

The circuit closing and breaking operation of the described switch is as follows: In the position of rest the contact lever 5, Figures 2 and 5, is supported by its pivot pin Z and by a fixed stop pin h. When member A is actuated by means of handle (1 as described above, the respective contact pin 0 engages under the insulating piece e whereby the lever b is slightly lifted. After the pin 0 has passed past the insulating piece 6 under the indirect action of spring f, Figure 1, the contact face of lever 1) comes tangentially into contact with pin 0, whereby the circuit of the conductors z and u, Figure 4, is closed. A weight Q, Figure 2, or in lieu thereof a small spring, servesto establish at once a good contact which during the time that the tilting member A executes its slight anticlockwise back movement, is a sliding contact until the contact pin 0 is stopped by the insulating piece 2, Figure 5. Now the tilting motion of member A commences, but is retarded because the contact pin 0 has to lift the contact lever 1) until the vertex 7, Figure 5, is reached. This takes place with sliding movement which from the point p is gradually accelerated up to the interruption of the contact. For, as the free end of lever I) is bent upwardly, as will be seen in Figure 5, the lever has the tendency to urge the contact pin 0 away to the right, so that lever 1) assists pin 0 in its prescribed movement, the latter thus being accelerated. This mutual influence causes a sudden separation of the two diverging contact members and thus a sudden breakage of the circuit. The actuated members, lever b and tilting member A, then return automatically to their position of rest by gravity.

Without the mode of operation as a time switch being interferred with, the described mechanism may also be used as a switch for permanently closing a circuit. To this end merely a slmple locking member needs be provided. This locking member may be formed for instance by a plug or a slide m,

Figure 1, forming a stop "for the tilting member A and arresting it while the circuit is still being closed, or a flap n, see Figure 6,. is hingedly mounted on the right-hand narrow edge of window i. The flap n carries a stop pin 1' which when the flap is turned into the window 2', projects into the path of handle at and sto s it. In addition, as marked by dotted lines in Figure 5, thefiap n obturates the starting portion of window 2'. Furthermore, as marked in Figure 1 in dotted lines, an axially .shiftable locking pin 0 may be provided which may engage each in one of two diametrically opposite bores s of the journal t, in order to stop the latter and therewith the tilting member A in positions corresponding to ,permaneapt switching. The pin 0 may be controlled by means of a double-armed hand lever 'w adapted to rock between two fixed pins 1),?) and held in locking and releasing position by a snap spring a: or the-like. In these arrangements a permanent closing is possible only after a time closing has been set. When the locking member through inadvertence or unauthorized manipulation from the first is in the position for rmanent closing, it has to be thrown over actuated at all.

What I claim and desire to secure by Letters Patent is v 1. In a time switch of the class described in combination a casing, a contact-making tilting member fulcrumed therein and a contact member cooperable therewith, an actuating handle for said tilting member adapted to move like a visehandle relatively to the fulcrum of said tilting member and enclosed in said casing, and means in connection-with said casing for guiding said handle in its circuit-closing movement in the prescribed path and for rendering it free for repeated circuitefore the switch can be closing manipulation only after the preceding closure has been broken.

2. In a time switch of the class described in combination a casing, a contact-making tilting member fulcrumed therein, a contact member cooperable therewith, an actuating handle for said tilting member adapted to move like a vise handle relatively to the fulcrum of said tilting member and enclosed in said casing, the latter having a window adapted to free said handle for manipulation from outside only for travelling its prescribed circuit-closing path and to obturate it after this closing until the closure has been broken again. i 5

3. In a time switch of the class described in combination a casing, a contact-making tilting member fulcrumed therein, a contact member cooperable therewith, an actuating handle for said tilting member adapted to move like a visehandle relatively to the fulcrum of said tilting member and enclosed in said casing, the latter having a window adapted to free said handle for manipulation from outside only for travelling its pretact pins on said tilting member, a contact. lever .fulcrumed in said casing and cooperable with said contact pins in alternation so as to close the circuit temporarily until said pin is removed by the tilting motion of said tllting member, an actuating handle for said tilting member enclosed insaid casing and adapted to move like a vise handle relatively to'the fulcrum of said member, and means in connection with said casing for guiding said handle in its circuit-closing movement in the prescribed path and for freein it for repeated circuit-closing manipu ation only after the preceding closure has been broken.

5. In a time switch of the class described in combination a casing, a tilting member fulcrumed therein, two oppositely disposed contact pins on said tilting member, a contact lever fulcrumed in said casing and cooperable with said contact pins in alternation so as to close the circuit temporarily until said pin is removed by the tilting motion of said tilting member, means in connection with said lever for automatically accelerating the circuitbreaking movement of said tilting member, an actuating handle for said tilting member with said contact pins in alternation so as toclose the circuit temporarily until said pin is removed by the tilting motion of said tilting member, means for permanently urging sai lever tolcontact-ma having an outwardl inclined free end adapted to accelerate sai pin in its removing motion under the influence of said urging means, means in-connection with said lever for automatically accelerating the circuit-breakingmovement of said tiltin member, an actuating handle for said tilting member enclosed in said casing and adapted to move like a vise handle relatively to the fulcrum of said member, and means in connection with said casing for guiding said handle in its circuitclosing movement in the prescribed'path and ing position, said lever for freeing it for repeated circuit-closing manipulatlon only after the preceding closure has been broken.

7. In a time switch of the class described in combination a casing a contact-making tilting member fulcrume therein and a contact member cooperable therewith, an actuating handle for said tilting member adapted to move like a vise handle relative to the fulcrum of said tilting member and enclosed in said casing, means in connection with said casing for guiding said handle in its circuitclosing movement in the prescribed path and for freeing it for repeated circuit-closing manipulation only after the preceding closure has been broken, and independent manipulative means for locking said tilting member in contact-making position to obtain permanent closure.

The fore oing specification signed this 30th day of anuary, 1932.

. CARL SNAY.

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