Abstract:
A rotary pulse switch wherein either one of two circuits can be selected depending on the direction of rotation of a turn shaft, and the selected circuit can be turned on and off consecutively. The switch includes a rotor having a conductor portion comprised of a ring-shaped common portion and a plurality of radially extending rotary contact portions. An insulating shutter plate is disposed between the rotor and contacts engageable therewith. The contacts include two adapted to engage the rotary contact portions and a single contact adapted to engage the common portion. Rotation of the shutter plate in either direction will electrically isolate one of the two contacts while electrically connecting the other of the two with the rotary contact portions.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a rotary pulse switch used for a transceiver and the like, and more particularly, to such a switch wherein either one of two circuits can be selected depending on the direction of rotation of a turn shaft, and the selected circuit can be turned on and off consecutively. 
     An object of the present invention is to provide such a rotary pulse switch which is simple in its construction and excellent in its electrical performance. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     For a better understanding of the present invention, reference may be had to the accompanying drawings wherein the same reference numerals have been applied to like parts and wherein: 
     FIG. 1 is an exploded perspective view, partially broken away, of one embodiment of a rotary pulse switch in accordance with the present invention, 
     FIG. 2a is a plan view of the rotor 14 used in FIG. 1, 
     FIG. 2b is a plan view of the insulating plate 20 used in FIG. 1, 
     FIG. 3 is a perspective view showing the inside of the case 25, 
     FIG. 4 is a cross-sectional side view of the switch when assembled, 
     FIGS. 5a, 5b and 5c are schematic diagrams used for explaining the operation of the switch, 
     FIGS. 6a and 6b are side views of a main portion of another embodiment according to the present invention, and 
     FIG. 6c is a plan view of a main portion of FIG. 6a. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIGS. 1-4 show, in various aspects, one embodiment of a rotary pulse switch in accordance with the present invention. A frame 1 formed from a metallic plate or the like has four arms, only two of which are shown at 2,2, extending rearwardly from its side panels. The frame 1 also includes notches 3,3 formed at the upper and front part of the side panels and a support 4 formed by bending back a tab portion of the upper side of the front panel and used to guide a steel ball 8. A shaft 5 having an outer handle portion is rotatably installed in the frame 1 by means of a bearing 6 attached to the front panel of the frame, and includes an inner shaft portion 5a extending inside the frame 1. The shaft portion 5a is provided with flat and parallel planes on two sides and has a cross-section generally similar to an oval. A cam wheel 7 is used as a stepping mechanism, and is fixed in position by iserting the shaft portion 5a into a shaft hole (not shown) located in the center of the cam wheel 7. The stepping mechanism is constructed in such manner that the steel ball 8 is accommodated movably in a hole (not shown) in the support 4 of the frame 1 and is pressed downward by means of a leaf spring 9 to maintain engagement between the ball 8 and the cam wheel 7. The leaf spring 9 is supported by means of the notches 3,3 on the frame 1. 
     A case 10 which may be made of synthetic resin, is provided with a circular recessed portion 11 used for accomodating a rotor 14, a circular shaft hole 12 centered in the base of the recessed portion 11 for receiving the shaft portion 5a, and four shoulders 13 at its corners. The diameter of the recessed portion 11 is made slightly larger than that of the rotor 14 and the depth of the recessed portion is almost equal to the thickness of the rotor 14. The rotor 14 is made from an insulating disc 15 laminated on one surface with copper or other conductive material and provided at its center with a nearly oval-like shaft hole 16 used for receiving the shaft portion 5a. The laminated copper forms a conductor portion 17 and is formed acording to the same method as copper foil is treated for producing a printed circuit board. 
     The conductor portion 17 forms a ring-shaped common conductor portion 18 and a plurality (even number) of rotary contact portions 19 extending radially from the periphery of the common conductor portion 18 and spaced apart at an equal angle so as to form an insulation part 15a between adjacent rotary contact portions 19. In addition, the rotary contact portions 19 are so arranged that they are positioned symmetrically with respect to the center of the shaft hole 16. The inside diameter of the common conductor portion 18 is slightly larger than the diameter of the shaft hole 16, and the number of rotary contact portions 19 is equal to the number of teeth or camming surfaces of the cam wheel 7 of the stepping mechanism. Alternatively, the rotor 14 may be formed by adhering a conductor portion 17 made from a thin metal sheet separately on the insulating disc 15. 
     An insulating plate 20 made of a sheet of synthetic resin or the like includes a semicircular shutter portion 21, a circular shaft hole 23 formed in a ring portion 22 disposed at the middle of its upper edge, and stoppers 24a and 24b formed by extending corner portions of the plate outward. The diameter of the shaft hole 23 is almost equal to the largest diameter of the shaft portion 5a, which corresponds to the diameter of the handling shaft 5. 
     An end case 25 made of synthetic resin includes a recessed portion 26 (FIG. 3) having a diameter equal to that of the recessed portion 11 of the case 10 and a circular shaft hole 27 located at its center for rotatably receiving the shaft portion 5a. The end case 25 further includes a pair of grooves 28a and 28b used for restricting the angle of rotation of the insulating plate 20, four shoulders 29 at its corners, and three grooves 30 disposed in its lower side for receiving fixed contact elements 31a, 31b and 31c. Each of the fixed contact elements 31a, 31b and 31c is made from a thin metal sheet with sufficient resiliency, and consists of a terminal portion 33 and a finger portion 32. The fixed contact element 31a has two fingers 32, so that it is formed like a Y. Contact chips 32a, 32b and 32c are provided on the tips of the respective fingers 32. In addition, each of the fixed contact elements 31a, 31 b and 31c is provided with a hole (not shown) in the terminal portion 33 and set in place by utilizing the hole and a boss 30a formed within the groove 30 of the case 25, and fixed there by calking the boss 30a against the hole. 
     The assembling of the rotary switch will now be explained in detail. After mounting the shaft 5 as well as the stepping mechanism in position on the frame 1, the case 10, rotor 14, insulating plate 20 and end case 25 are set in that order in the shaft portion 5a of the shaft 5 by way of the shaft holes 12, 16, 23 and 27. At this juncture, the shoulders 13 and 29 of the cases 10 and 25, respectively, are aligned with respect to the arms 2 of the frame 1. Lastly, the forward ends of the arms 2 are bent at the rear panel of the end case 25 to fix all the parts to the frame 1. During this assembling, the cases 10 and 25 must be so arranged that the respective recessed portions 11 and 26 face each other, and the rotor 14 must be housed in the recessed portion 11 of the case 10 so that the conductor portion 17 on the rotor 14 faces the fixed contact elements 31a, 31b and 31c attached to the end case 25. In addition, the insulating plate 20 must be so arranged that the stoppers 24a and 24b are positioned within the grooves 28a and 28b of the end case 25 and rotatably mounted on the shaft portion 5a in close contact with the conductor portion 17 of the rotor 14. 
     The operation of the switch will be explained by reference to FIGS. 5a, 5b and 5c. When the switch is not operated, it can be seen from FIG. 5a that the lower part of the conductor portion 17 of the rotor 14 is in contact with the shutter portion 21 of the insulating plate 20, the contacts 32a, 32a of the fixed contact element 31a are in contact with the common conductor portion 18 of the rotor 14, and the contacts 32b and 32c of the fixed contact elements 31b and 31c are located symmetrically with respect to the center of the shaft portion 5a. When the shutter portion 21 of the insulating plate 20 is turned and held at the position N indicated by the full line as illustrated in FIG. 5a, the contacts 32b and 32c are in contact with the insulation parts 15a, 15a. When the shutter portion 21 is rotated in either clockwise or counter-clockwise direction and thus located at either of the positions S or T as indicated by the dotted line in FIG. 5a, one of the contacts 32b or 32c is blocked so as not to contact the rotor 14, and the other is on the insulation part 15a of the rotor 14. Therefore, in either case, the fixed contact elements 31a, 31b and 31c are electrically blocked from each other and the switch is under the &#34;OFF&#34;condition. 
     Assume now that the shutter portion 21 is in the position N or T. If the rotor 14 is turned clockwise, in the drawing, by means of the handle portion of the shaft 5, the insulating plate 20 is rotated together with the rotor 14 (the insulating plate 20 revolves together with the rotor 14 due to the friction between the shaft portion 5a and the shaft hole 23 or the viscosity resulted from grease applied to the conductor portion 17) until the stopper 24a abuts on the upper inside wall of the groove 28a of the end case 25. This condition is illustrated in FIG. 5b. In FIG. 5b, any electrical connection between the contact 32c and the rotor 14 is blocked by the shutter portion 21. On the other hand, the contact 32b is in contact with a rotary contact portion 19 due to the rotation of the rotor 14 while the shutter portion 21 is removed from the position of the contact 32b. As a result, electrical connection between the fixed contact pieces 31a and 31b  is established through the conductor portion 17. When the rotor 14 is further rotated while the insulating plate 20 slides on the shaft 5, contact 32b is disengaged from the rotary contact portion 19 and comes into contact with the next insulation part 15a, one step being instantly advanced by means of the stepping mechanism, and the switch returns to the &#34;OFF&#34; state. Under this state, the insulating plate 20 is located at the position illustrated in FIG. 5b (In FIG. 5a, it corresponds to the position S). It can thus be seen that the contacts 32a, 32a are always in contact with the common conductor portion 18 regardless of the rotation of the insulating plate 20. If the rotor 14 is further rotated in the same direction, the contact 32b is alternately engaged and disengaged from the rotary contact portions 19 every time the stepping mechanism advances one step, and the on-off operation is therefore repeated between the fixed contact elements 31a and 31b only. 
     Next, when the rotor 14 is rotated in the counter-clockwise direction in the drawing, the insulating plate 20 is turned in the reverse direction as compared with the previous operation until the stopper 24b abuts on the upper inside wall of the groove 28b of the end case 25. At this stage, the electrical connection between the contact 32b and the rotor 14 is blocked by the shutter portion 21, and the contact 32c comes into contact with and is disengaged from the rotary contact portions 19 every time the switch advances through one step due to similar operation as mentioned above. As the result, the on-off operation is repeated between the fixed contact elements 31a and 31c only. 
     In other words, the rotary switch according to the present invention may be made to energize either one of two circuits depending on the direction of rotation of the rotor 14. Therefore, the switch can be used to select a station for a transceiver or the like by combining it with a pulse generation circuit since the selected circuit is turned on and off consecutively. 
     After the switch is once operated, the insulating plate 20 will be held at either position illustrated in FIG. 5b or 5c, due to its frictional engagement with the shaft portion 5a, provided that the rotor 14 is at a standstill. 
     In spite of the simplicity in its construction, the rotary pulse switch according to this invention can operate as described above and is highly reliable in its electrical performance because the contact portions are of self-cleaning type. In addition, as compared with a device of leaf switch type, the generation of chattering is extremely less and smooth operation is assured in view of the structure of the contact portions. Consequently, the electrical performance as rotary pulse switch and its productivity are greatly improved. 
     Referring to FIG. 6 which shows another embodiment of the present invention, an insulating plate 40 is so constructed that its shutter portion 41 is made smaller in area and larger in its thickness than that of the shutter portion of the insulating plate 20 of the first embodiment. The fixed contact elements 42 are provided with contacts 43 at the tips thereof as well as curved portions 44 at the middle portions thereof, and establish an electrical path through the rotary contact 19 on the rotor 14. When the insulating plate 40 is rotated, a respective curved portion 44 is pushed upward by means of the shutter portion 41 to bend the respective fixed contact element 42 and disengage the contact 43 from the surface of the rotor 14. 
     In all cases, it is understood that the above-described embodiments are merely illustrative of but a small number of the many specific embodiments which can represent application of the principle of the present invention. Numberous modification can be readily made by those skilled in the art without departing from the spirit and scope of the invention.