Motor-Driven Time Switch

This invention relates to a motor-driven time switch.

In a conventional motor-driven time switch, in order to supply current to the coil winding of the motor, lead wires are connected to the ends of the coil windings, and the lead wires thus connected are laid outside the casing so that they are connected to the terminals of the time switch.

Accordingly, it is necessary to connect the lead wires to the ends of the coil winding and the terminals, for instance, by soldering. Therefore, the conventional motor-driven time switch can be assembled by only persons skilled in the art; that is, it is low in work efficiency. Furthermore, since the lead wires are laid outside the casing, they may be disconnected or cut by being jerked or caught, for instance, by the hand or the assembling tools.

Accordingly, an object of this invention is to eliminate the above-described difficulties accompanying a conventional motor-driven time switch.

More specifically, an object of the invention is to provide a motor-driven time switch in which the time switch mechanism and the electric motor can be readily combined together; that is, the assembling work is achieved with high efficiency, and the probability of the lead wires being broken is decreased.

The foregoing object and other objects of the invention have been achieved by the provision of a motor-driven time switch comprising: a time switch mechanism including a time setting cam, a plurality of leaf spring contacts forming switching means operated by rotation of the time setting cam, and a plurality of terminals for connecting the leaf spring contacts to external equipment; and an electric motor with a coil for rotating the time setting cam, which, according to the invention, comprises: a coil bobbin on which the coil is wound, the coil bobbin having a plurality of terminal pin mounting parts; and terminal pins which are press-fitted in terminal pin mounting parts selected out of the plurality of terminal pin mounting parts, and connected to terminals selected out of the plurality of terminals, both ends of the coil being wound on the terminal pins thus press-fitted.

The nature, principle and utility of the invention will become more apparent from the following detailed description when read in conjunction with the accompanying drawings.

In the accompanying drawings:

FIG. 1 is a side view, with parts cut away, showing one example of a motor-driven time switch according to this invention;

FIG. 2 is a sectional plan view of the motordriven time switch shown in FIG. 1;

FIG. 3 is a sectional side view of an electric motor in the motor-driven time switch according to the invention;

FIG. 4 is a plan view of a coil bobbin in the electric motor shown in FIG. 3 wherein section line III--III is the line along which the sectional side view of FIG. 3 has been taken;

FIGS. 5(a) and 5(b) are side views of the coil bobbin, showing different arrangements of terminal pins;

FIG. 6 is a plan view showing essential parts of a casing;

FIG. 7 is a side view showing essential parts of the terminal of a contact board; and

FIG. 8 is a sectional front view showing essential parts of the terminal of the contact board and a terminal pin mounting part.

One preferred embodiment of this invention will be described with reference to the accompanying drawings.

A motor-driven time switch of the invention, as shown in FIGS. 1 and 2, comprises: an electric motor 10 secured to a casing 1 with screws 11; and a time switch mechanism 13 disposed between the casing 1 and its cover 12.

The motor 10, as shown in FIG. 3, comprises: a coil bobbin 2 on which a coil 3 is wound, a bobbin cover 14 engaged with the coil bobbin 2 at its one side; a yoke 4 having comb-shaped pole teeth 4a; and a motor casing 5 having comb-shaped pole teeth 5a. The yoke 4 and the motor casing 5 are arranged on both sides of the coil bobbin 2 engaged with the bobbin cover 14 in such a manner that the pole teeth 4a and 5a are inserted into the central hole 2a of the coil bobbin 2. A rotor 6 with permanent magnets 15 formed outside is rotatably supported in the circle formed by the pole teeth 4a and 5a with its shaft 16 as the axis of rotation. FIG. 3 is a sectional view of the motor taken along line III--III in FIG. 4.

The coil bobbin 2, as shown in FIGS. 3, 4 and 5, comprises: a cylindrical coil-winding part 2b; flanges 2c and 2d on both ends of the coil-winding parts 2b; a flange protrusion 2e extended radially from the flange 2d; and a plurality of terminal pin mounting parts (terminal pin holders) 2f. The terminal pin mounting parts 2f are formed on the outer end of flange protrusion 2e in such a manner that they are extended along the axis of the coil bobbin 2. The flange protrusion 2e has a guide groove 2h in which one end portion of the wire of the coil 3 is inserted, and a projection 2i with which the other end portion of the wire is engaged.

The terminal pin mounting parts 2f have throughholes extended along the central axis, into which terminal pins 17 are press-fitted. The coil winding end portions 3a and 3b are soldered to the first end portions of the terminal pins 17.

As shown in FIGS. 1 and 6, guide holes 1a are formed in the casing 1, to receive the above-described terminal pin mounting parts 2f.

The time switch mechanism 13 is accommodated in the casing 1 with the cover 12, as was described above. The output gear 6a of the rotor 6 is engaged with the input gear 18 of a gear train. The output gear 19 of the gear train is engaged with a gear (not shown) which is integral with a time setting cam 7. The time setting cam 7 may be integral with a main shaft 7a, or it may be fixedly secured with the main shaft 7a which is formed separately. The time setting cam 7 is made up of two cams, namely, a large cam 7j and a small cam 7k. The large cam 7; has a step 7b, a low cam surface 7c, a high cam surface 7d, and an envelope surface 7e formed by gradually increasing a rotating radius. The end portions of leaf spring contacts 8 and 8' are abutted against the large cam 7j. The small cam 7k, being substantially similar in configuration to the large cam 7j, has a step 7f, a low cam surface 7g, a high cam surface 7h, and an envelope surface 7i formed by gradually increasing a rotating radius. The end portion of a leaf spring contact 8" is abutted against the small cam 7k. The terminals 8a, 8a' and 8a" of the leaf spring contacts 8, 8'0 and 8", and the terminal 9a of a common leaf spring contact 9 are inserted in grooves formed in the casing 1, and are fixedly secured by means of the cover 12. Contacts 21, 22 and 23 are fixedly provided on the other end portion of the leaf spring contacts 8, 8' and 8", respectively.

The above-described guide holes 1a are formed in the casing 1 in such a manner that they confront with the terminals 8a, 8a', 8a" and 9a, respectively, and, when the terminal pin mounting parts 2f are inserted into the guide hole 1a with the motor 10 secured to the casing 1, the terminal pins 17 are positioned beside the terminals 8a, 8a', 8a" and 9a. As shown in FIG. 7, inverted-.OMEGA.(ohm)-shaped terminal pin press-fitting grooves 8b and 9b are formed in the leaf spring contact 8, 8', 8" and 9. The terminal pins 17 are press-fitted in the grooves 8b and 9b as shown in FIG. 1 and 8.

FIG. 2 shows the motor-driven time switch in which the motor 10 with the coil bobbin 2 shown in the part (a) of FIG. 5 is combined with the casing 1 accommodating the time switch mechanism 2.

The configuration of the time setting cam 7 is not limited to that shown in FIG. 2. The number and the configuration of the leaf spring contacts are not limited to those shown.

Of the terminal pin mounting parts 2f of the coil bobbin 2, those which should receive the terminal pins 17 should be selected according to the function of the time switch mechanism and the operation of external equipment connected thereto. This will be described in more detail. In order that the motor is operated in correspondence to the function of the time switch mechanism or the operation of the external equipment connected thereto, the terminal pins 17 are press-fitted in the terminal pin mounting parts 2f selected, and are then connected to the two ends of the coil winding. If the motor 10 with the coil bobbin 2 shown in FIG. 5(b) is secured to the casing 1, and then the terminal pins 17 are fixedly coupled to the terminals 8a and 9a of the leaf spring contacts 8 and 9, then a time switch different from the above-described one can be obtained.

As is apparent from the above description, the selective use of the terminal pin mounting parts permits the motor-driven time switch of the invention to operate for a variety of circuits.

The motor-driven time switch thus constructed provides the following advantages: First, the soldering work is unnecessary. The coil winding end portions 3a and 3b can readily be connected to the terminal pins 17; that is, the work efficiency is improved as much. Furthermore, since the coil winding end portions 3a and 3b are connected to the terminal pins 17 inside the casing 1 and the motor casing 5, a difficulty of the coil wire being broken is substantially eliminated.

By changing the combination of the terminal pins 17 of the motor 10 and the terminals 8a, 8a', 8a" and 9a of the leaf spring contacts 8, 8', 8" and 9, a variety of time switches different in operation can be obtained. As was described above, in the motor-driven time switch of the invention, a plurality of terminal pin mounting parts 2f are provided, and the guide holes 1a are formed in the casing 1 of the time switch mechanism 13 in such a manner that they can receive the terminal pin mounting parts 2f, respectively. Therefore, if the terminal pin mounting parts 2f are so selected that the motor 10 operates suitable for a given operating circuit and the terminal pins 17 are press-fitted in the terminal pin mounting parts 2f thus selected, then a time switch suitable for the operating circuit can be formed. That is, a variety of motor-driven time switches can be obtained by changing the combination of the terminal pins 17 and the terminal pins mounting parts 2f.

As is apparent from the above-description, a variety of motor-driven time switches can be manufactured with only one kind of casing 1 for the time switch mechanism 13. That is, the number of components is not increased, and the assembling efficiency is improved.

The motor-driven time switch of the invention is constructed as described above. Therefore, it can be assembled without soldering work. The terminals of the coil can readily be connected to the terminal pins; that is, the work efficiency is improved. Furthermore, since the ends of the coil are connected to the terminal pins only inside the housing, the lead wires will never come out of the housing, and accordingly a danger of the coil wire being broken is substantially eliminated. Thus, the motor-driven time switch of the invention should be highly appreciated in practical use .