US2217414A - Time switch mechanism - Google Patents

Description

Oct. 8, 1940. LENEHAN 2,217,414

T IME SWITCH MECHANIS M Original Filed March 28, 1956 Msu/af/an WITNESSES; INVENTOR WM Berna/d5. en hon.

AT NEY Patented Oct. 8, 1940 UNITED STATES TIME SWITCH MECHANISM Bernard E. Lenehan, Bloomfield, N. 3., assignor to Westinghouse Electric & Manufacturing Company, East Pittsburgh, Pa., a corporation of Pennsylvania Application March 28, 1936, Serial No. 71,432 Renewed January 18, 1939 8 Claims.

My invention relates to time switches of the type driven by a constant speed motive device and arranged to open or close a load circuit for a fixed time interval each day or for a. variable time interval dependent upon the time of rising and setting of the sun. Such switches are commonly used for controlling resistance load circuits, such as street lighting cir uits, advertising display circuits or off-peak heater apparatus, and are designed to interrupt comparatively heavy non-inductive currents without the use of auxiliary contactors. For such service it is necessary to use comparatively heavy contact members, and to eiiect opening and closing of the load circuit with quick positive movements of the contact members, to thereby avoid excessive burning. I

It is an object of my invention to provide a novel switch operating mechanism for time switches of the type mentioned above which will produce positive opening and closing motions of the contact members by means of comparatively simple mechanism.

Other objects of my invention will become evident from the following detailed description taken in conjunction with the accompanying drawing, in which:

Figure 1 is an elevational view of the operating mechanism of a time switch embodying my invcntion, removed from its outer casing (not shown), and having certain parts omitted for simplicity;

Fig. 2 is a side elevational view of the operating mechanism shown in Fig. 1;

Fig. 3 is an enlarged perspective view showing the relationship of rollers and spring contact members used in the practice of my invention;

and

Fig. 4 is a fragmentary elevational view similar to Fig". 1, showing the switch operating parts in the positions which they assume when the switch contacts are closed.

Referring to Figure 1 in detail, a case i is provided to which a rotatable time dial 3 is secured by any suitable fastening 2. The time dial 3 designed to be driven one revolution during each twenty-four hours, and is preferably marked with indicia corresponding to the hours of the day, arranged to pass adjacent to a fixed pointer 5. The time dial 3 is driven, through a suitable gear train (not shown), by any suitable constant motive device of a kind suitable for driving horological instruments, such as a synchronous electric motor 5.

An on lever 1 and an off lever 9 are provided for initiating closing and opening move ments of the switch contacts at times determined by the rotation of the time dial 3.

The on lever 1 and the off lever 9 are arranged to rotate with the time dial 3 and are individually controlled by fastening members 1! and [3, respectively, which extend through slots M in the time dial 3 and are preferably operated by suitable mechanism (not shown) for introducing a precessional movement depending upon the variations of time of sunrise and sunset in the latitude at which the time switch is used. As such mechanism forms no part of the present invention, it has been omitted from the drawing.

The ofi lever 9 is provided with an opening pin I5 for operating the switch mechanismto cause opening of the switch contacts. A closing pin I! is mounted 'upon the on lever I for a similar purpose in effecting closure of the switch contacts.

The opening pin l5 and the closing pin I! are driven in counter-clockwise direction by the time dial 3 in arcuate paths such as to engage an operating member 25, a resetting lever 19 or a latch 21, in a manner to be described. The operating member is of bell-crank form and is mounted to rotate freely about a. post 2| secured to the base I. Referring to Fig. 2, a pair of cylindrical spacers 22 are provided on the post 21 for maintaining the operating member 25 in a plane closer to the base I than the plane of the time dial 3. The operating member 25 is flared at its outer end (toward the right in Fig. 1) to provide an inclined face portion 38 for engagement with the closing pin [1.

The esetting lever 65 is of substantially L- shape and is mounted to rotate freely about the post 2|, but in a plane above the time dial 3 and operating member '25. The resetting lever 19 is provided with a curved camv surface 29 for engagement with the opening pin l5, and with a shoulder portion 23 arranged to abut a post 24 which is preferably an integral part of the motor 5, in order to limit movement of the resetting lever I 9 toward the axis of the time dial 3.

The latch 21 is pivotally secured to the resetting lever I9 by means of a comparativeiy long pin 29, so as to lie in a plane only slightly above that of the operating member 25. The latch 21 is biased by means of a resetting spring 3! so as to rotate in a counter-clockwise direction into engagement with a pin 26 carried by the operating member 25. The latch 27 is provided with a catch portion 32 which, in the open position of ie switch as shown in Fig. 1, engages the pin 26 so as to prevent clockwise movement of the operating member 25 in relation to the latch 21. The resetting spring 3! is secured to a fixed abutment, which is preferably a post 33 constituting part of the motor 5.

The main contact assembly of the time switch is insulated from the base I by means of a strip of insulating material 3 and insulating spacers 31, and comprises a pair of flat bronze springs 36 mounted in substantially parallel cantilever relationship by means of the insulating spacers 31 and bolts 40. The free ends of the bronze springs 38 are cut away on opposite sides so as to provide a pair of offset areas 38, 39 (see 3), for separate engagement with a pair of rollers 35 carried by the operating member 25.

The time switch is provided with a pair of silver main contacts, preferably of cylindrical form, mounted on the inner faces of the springs 36 in positions to be firmly engaged under the tension of the latter when the rollers 35 are in their outermost position with reference to the springs 35. The arrangement of the rollers 35 and springs 36 is such that when the rollers 35 are in their innermost position with reference to the springs 36, they are in a condition of stable mechanical equilibrium, but upon movement of the rollers 35 to a slight extent to the left in Fig. 1, a range of positions of unstable equilibrium is encoun ered, in which the tension of the springs 35 tends to eject the rollers 35 and rotate the operating lever in the clockwise direction.

A manual operating handle 45 is provided for opening and closing the time switch manually when such operation is necessary. The operating handle 45 is ri idly secured to a pair of flat plates 43 lying on either side of the operating member 25 and rotatabiy secured thereto by means of a pivot pin 44.

The operation of the above-described apparatus may be set forth as follows: Referring to Fig. l which shows the time switch parts in a position corresponding to open circuit condition, as the closing pin H is driven in a counter-clockwise direction by the motor 5, it engages the face portion 28 of the latch 21 and rotates the latter about the pivot 29 for an angular distance sufficient to carry the catch portion 32 beyond the pin 26. Further movement of the closing pin 11 in the counter-cloclnvise direction, while the latter still engages the face portion 28, causes clockwise movement of the operatin member 25 because of engagement of the closing pin l. with the inclined face 33. As the catch portion 32 of the latch 21 is clear of the pin 26, upon initial movement of the operating member 25 in a clockwise direction, the latter is free to rotate, and the rollers 35 are moved from their initial stable position into the range of positions in which the springs 35 exert a force on them. The rollers 35 are accordingly ejected from between the springs 36, and the contacts 41 are permitted to engage firmly under the bias of the springs 38. Ejection of the rollers 35 causes the operating member 25 to rotate sufliciently in the clockwise direction for the inclined face 35 to move out of the path of the closing pin l1. As the closing pin I! continues to rotate in the counter-clockwise direction, it rides off of the face portion 23 of the latch 2?, freeing the latch.

In the fully closed position of the switch, the latch 27 and operating member 25 assume the relative positions shown in Fig. 4, and the pin l! is released from the face portion 28 of the latch 21 and the inclined face portion 30 of the operating member 25. Upon further continued counter-clockwise movement of the time dial 3, the opening pin l5 engages the curved cam surface 20 of the resetting lever 19 and causes the latter to rotate in clockwise direction about the post 2! against the tension of the resetting spring 3%. As the resetting lever 19 rotates in a clockwise direction, the catch portion 32 of the latch 21 is drawn below the pin 25 in a position to engage the latter.

When the opening pin [5 arrives at a position approximately under the time point 6, the resetting lever IB is released and rotates about the post 2| in counter-clockwise direction under the tension of spring 3|. As the resetting lever 19 rotates in the counter-clockwise direction, the catch portion 32 of the latch 21 carries the pin 25 in the same direction, thereby effecting movement of the rollers 35 from the position shown in Fig. 4 to the position shown in Fig. 1. The time switch is thereby restored to the fully opened position as shown in Fig. 1, ready for a further closing operation.

The manual operation of the switch by the operating handle is as follows: Referring to Fig. 1, in order to close the switch manually the handie 45 is moved in the downward direction. Upon initial movement of the handle 45 in the downward direction, the corner of the upper plate 43 engages the side of the latch 21 and rotates the latter about its pivot 29 in the clockwise direction to a sufiicient extent to free the pin 25 from the catch portion 32. Further movement of the operating handle 45 causes the latter to engage the inner surface of the resetting lever I9, and actin upon the latter, to force the rollers 35 from their stable position to the position shown in Fig. 4'. In the final closing position of the switch the parts assume the relative positions shown in Fig. 4.

The opening operation of the switch by means of the operating handle 45 is effected by moving the latter in the upward direction. Upon movement of the operating handle 45 in the upward direction it engages the inner horizontal edge of the operating member 25 and rotates the latter in the counter-clockwise direction, thereby forcing the rollers 35 between the springs 26. As the operating member 25 moves in counter-cloclz'i '2 direction, the pin 25 is carried past the catch 1 tion 32 into a position to be engaged by the latter,

while the resetting lever I9 is held in the position shown in Fig. 4 by means of the shoulder 23 in engagement with the post 2 3. In the fully opened position of the switch, the parts assume effected without departing from the spirit and scope of my invention. I desire, therefore, that only such limitations shall be imposed as are indicated in the appended claims.

I claim as my invention:

1. In a time switch, a roller; means for restricting movement of said roller to a predeter mined path including a stable position, an unstable range of positions and a switch-operating position; resilient biasing means acting upon said roller in a direction substantially perpendicular to said path, said biasing means being deformed for storage of energ when said roller is in said stable position, and being effective to produce a force component acting to move said roller toward said switch operating position only when said roller is in said unstable range of positions; time-controlled means for slowly moving said roller from said stable position to said unstable range of positions to thereby initiate the release of the stored energy of said biasing means to accelerate said roller toward said switch-operating position; contact members arranged to be operated in response to released energy of said biasing means when said roller is in said switch operating position; and time-controlled means for restoring said roller to said stable position.

2. In a time switch, a roller; means for restricting movement of said roller to a predetermined path including a stable position, an unstable range of positions and a switch-operating position; resilient biasing means acting upon said roller in a direction substantially perpendicular to said path, said biasing means being deformed for storage of energy when said roller is in said stable position, and being effective to produce a force component acting to move said roller toward said switch operating position only when said roller in said unstable range of positions; time-controlled means for slowly moving said roller from said stable position to said unstable range of positions to thereby initiate the release or" the stored energy of said biasing means to accelerate said roller toward said switch-operating position; contact members arranged to be operated in response to released energy of said biasing means when said roller is in said switch operating position; a resetting spring effective, when fully deformed and connected to said roller, to restore said roller to said stable position; a latch effective when in engaging position to mechanically connect said resetting spring to said rollers; and time-controlled means for gradually deforming said resetting spring and for suddenly releasing the same when said latch is in engaging position, to thereby restore said roller to said stable position against the action of said biasing means.

3. In a time switch, a roller; a pivoted crank for restricting movement of said roller to an arcuate path including a stable position, an unstable range of positions and a switch-operating position; a flat spring acting upon said roller in a substantially radial direction with reference to said arcuate path, said spring being deformed for storage of energy when said roller is in said stable position, and being effective to produce a force component acting toward said switchoperating position only when said roller is in said unstable range of positions; a timing motor having a rotary timing element; means carried by said rotary timing element for engaging said crank to cause movement of said roller from said stable position to said unstable range of positions to thereby initiate the release of the stored energy of said biasing element for accelerating said roller toward said switch-operating position; contact members arranged to be operated in response to released energy of said flat spring when said roller is in said switch-operating position; a resetting spring eiliective when fully deformed and connected to said roller to restore said roller to said stable position; a latch effective when in engaging position to mechanically connect said resetting spring to said roller; and additional means carried by said rotary timing element for gradually deforming said resetting spring and for suddenly releasing the same when said latch is in engaging position, to thereby restore said roller to said stable position against the action of said flat spring.

4. In a time switch, a pair of fiat cantilever type springs mounted in substantially parallel relationship, an operating element having a pair of rollers in cooperative relationship with said springs, said operating element being movable from a stable position in which said springs are separated at their free ends by said rollers through a range of positions in which movement of said rollers in a direction substantially parallel to said springs is effected by a force derived solely from said springs, means for initiating movement of said rollers from said stable position to said range at a predetermined time, means for resetting said rollers to said stable position at a different predetermined time, and contact members mounted upon said springs.

5. In a time switch, a pair of flat cantilever type springs mounted in substantially parallel relationship and having their free ends normally separated by a predetermined distance, an operating element having a pair of rollers arranged to be inserted between said springs, said rollers having a diameter slightly greater than said predetermined distance, said springs each being formed with an ofiset surface for separate engagement with a single one of said rollers, said operating element being movable from a stable position in which said springs are separated at their free ends by said rollers through a range of positions in which movement of said rollers in a direction substantially parallel to said springs is efiected by a force derived solely from said springs, means for initiating movement of said rollers from said stable position to said range at a predetermined time, means for resetting said rollers to said stable position at a different predetermined time, and contact members mounted on said springs.

6. In a switch, electrical contact means for opening and closing an electrical circuit, a pair of switch arms relatively movable towards and from each other for operating said contact means, said arms being biased towards a predetermined position wherein said contact means is in closed condition, means for actuating said arms against said bias for Opening said contact means, said actuating means including a pair of parallel rollers each engaging only a separate one of said switch arms, and means mounting said rollers for independent rotation, said means being operable for substantially simultaneously actuating said rollers against their respective switch arms for moving said switch arms against their bias.

'7. In a switch, a pair of spaced switch arms biased towards each other, a projection on each of said arms, said projections being substantially parallel and staggered, a roller assembly including a pair of axially aligned rollers each engageable with only a separate one of said projections for separating said switch arms against said bias, said rollers having diameters slightly larger than the spacing betwen said switch arms, a shaft mounting said rollers for independent rotation, said shaft being movable for introducing said roller assembly between said projections, and contact means controlled by said switch arms.

8. In a switch, a pivoted lever, a roller assembly including a pair of axially aligned rollers mounted on said lever for independent rotation, said roller assembly being movable in a path about the pivot of said lever, a pair of switch control arms biased towards each other in the path of said roller assembly, each of said switch control arms being positioned to engage only one of said rollers as said roller assembly is moved between said switch control arms for separating said switch control arms, and contact means controlled by said switch control arms.

BERNARD E. LENEHAN.

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