US 3681658 A
Description (OCR text may contain errors)
United States Patent Naoi et al. [4 1 Aug. 1, 1972  DEVICE FOR PROTECTING A  References Cited gggg gg ggggg gg AN INTERNAL UNITED STATES PATENTS  Inventors: Keigo Nani; Kammi Omki, both of 3,307,124 5/1962 Carlsonu ..317/ 10 R Katsuta, Japan Primary Examiner.lames D. Trammell  Asslgneez llitachl, Ltd., Tokyo, Japan Attorney craig Amend & Hm  Filed: Dec. 3, 1970 21 Appl. No.: 94,768  ABSTRACT A device for protecting a starting motor for an inter-  Foreign Applicati .n Priority Data nal combustion engine prevents misoperation of the starting motor. A normally opened contact which is Dec. 8, 1969 Japan ..44/97884 dosed by the output voltage of a generator is nected in an ignition circuit connected at an end  "317/13 290/37 2 g thereof with a battery, and a normally closed contact  Int Cl 7/093 which is opened by the output voltage of the generator  Fie'ld 290/37 317/13 is connected in a starting motor switch circuit, so that the ignition circuit is closed and the starting motor switch circuit is opened when the output voltage of the generator is above a definite level.
2 Claim, 2 Drawing Figures P'ATE'NTEDmc 11912 I 3.681.658
INVENTORS BYCNLQ, AM SMW i-NLQL ATTORNEYS DEVICE FOR PROTECTING A STARTING MOTOR OF AN INTERNAL COMBUSTION ENGINE BACKGROUND OF THE INVENTION The present invention relates to a device for protecting a starting motor of an internal combustion engine, and more particularly to a device for preventing the pinion of the starting motor from being brought into engagement with the ring gear of the engine when the key switch is misoperated to drive the starting motor while the engine is running.
In recent years, the performance of the engine has been much improved, so that it is sometimes difficult to tell if the engine is running due to its small mechanical sound made while running. Accordingly, the driver or operator often drives the starting motor by mistake without noticing the engine running while the engine is idling. Such an operation leads the pinion gear generate a metallic noise. Heretofore, an independent relay device has been provided to prevent such a reengagement of the pinion. However, such a construction has been disadvantageous and impractical in that many parts are needed, the construction becomes complicated, the construction becomes expensive and so forth.
SUMMARY OF THE INVENTION An object of the present invention is to provide a device for preventing the misoperation of the starting motor wherein a normally opened contact is connected in parallel with the ignition circuit, a normally closed contact is connected in series with the starting motor circuit, and the two contacts are made to'be induced by a voltage detecting coil for detecting the output voltage of the generator whereby the starting motor circuit is cut when the output voltage of the generator is above a definite level.
Another object of the present invention is to provide a device for protecting a starting motor which is simple in construction and has high reliability by making the protection device directly connected with the conventional voltage regulator for the charging generator by using the output voltage detecting coil in common.
BRIEF DESCRIPTION OF THE DRAWING DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Now referring to FIG. 1, the output terminals of the dynamo coils of a charging generator 1 including three dynamo coils 2 in Y-connection and a field coil 3 are connected with a battery 5 through a full-wave rectifier.
4. An end of the field coil 3 is grounded and the other end thereof is connected with the battery 5 through a couple of normally closed contacts 7 and 8 of a voltage regulator 6, a diode 9, an indicator lamp 10 and an ignition switch 11. The reference numeral 12 indicates a voltage detecting coil for opening the foregoing normally closed contacts 7 and 8 which is operated by the output voltage of the generator 1. The reference numeral 13 indicates a resistor connected between the normally closed contacts 7 and 8. A starting motor 14 includes a normally opened fixed contact 15 and a normally opened movable contact 16, both of which are opened and closed by the operation of the voltage coil 18 acting in response to the opening and closing of the starting switch 17. The reference numeral 19 denotes a voltage detecting coil connected with the neutral point of the dynamo coils 2 of the generator 1 through a diode 20, which is connected with the battery 5 through a normally closed movable contact 21, a normally closed fixed contact 22 and a starting switch 17. The normally closed movable contact 21 is opened by the operation of .the voltage detecting coil 19. A normally opened movable contact 23 and a normally opened fixed contact 24 make a normally opened contact connected in parallel with an ignition switch 11. This contact 23, 24 is closed by the operation of the voltage detecting coil 19. The reference numeral 25 indicates a load such as an ignition load in case of a gasoline engine car which is operated after the ignition switch 11 is closed.
In the circuit as described above, the voltage detecting coil 19 employed in the device for protecting the starting motor is secured to a supporting bracket 28 together with a fixed iron piece 27 as shown in FIG. 2. The voltage detecting coil 19 is wound around an iron core 26. The foregoing normally opened movable contact 23 which is closed by the operation of the voltage detecting coil 19 is fixed on the end of an elastic iron plate 29 which is fixed at the other end thereof to the top end 27a of the fixed iron piece 27. The foregoing normally opened fixed contact 24 is disposed on the top end of a lead member 24a which is riveted on the supporting bracket 28 at such a position that the fixed contact 24 may be faced with the said movable contact 23. On the other hand, the normally closed movable contact 21 riveted through an insulating plate 31 on an L-shaped metal member 30 which is fixed to said iron plate 29. The normally closed fixed contact 22 is fixed to an L-shaped member riveted on the supporting bracket 28 so that the fixed contact 22 may be faced or in contact with said movable contact 21.
In operation, when the ignition switch 11 is closed field current flows into the field coil 3 through the indicator lamp 10, the diode 9 and the normally closed contacts 7 and 8 of the voltage regulator 6 to excite the generator 1. Then, in response to the turning on of the starting switch 17, the starting current flows into the voltage coil 18 of the starting motor 14 through the normally closed contacts 21 and 22. When the current flows through the coil 18, the normally opened contacts 15 and 16 are closed by the induction force thereof and the starting motor 14 rotates to start the engine rotation. When the engine starts to run, the generator is driven by the torque of the engine rotation. In response to the operation of thegenerator, the volt age detecting coil 19 operates to close the normally opened contacts 23 and 24 and open the normally closed contacts 21 and 22 whereby the field current flows through the contacts 23 and 24 and the starting motor switch circuit is completely cut. Therefore, even if the starting switch 17 is turned on by mistake at the time of idling, the starting motor 14 is not supplied with current, since the normally closed contacts 21 and 22 between the dynamo coil 2 of the generator 1 and the voltage detecting coil 19 is provided for exciting the voltage detecting coil 19 at the time of starting of the starting motor 14, for preventing the release of the normally closed contacts 21 and 22 and for exciting the voltage detecting coil 19 only by the voltage from the neutral point of the generator 1.
Since the normally closed contacts 21 and 22 for opening and closing the starting motor circuit uses the voltage detecting coil 19 for the voltage regulator 6 in common, there is no need to provide a separate protecting relay device. And further, by the provision of the normally closed contact for controlling the starting 'motor circuit on the movable elastic iron plate 29 which holds the normally opened contact, the whole construction of the device can be simplifiedand can be manufactured at low cost.
What is claimed is l. A device for protecting a starting means in an internal combustion engine comprising:
ignition switch and a voltage regulator circuit which is connected to said field coil; e. a first set of normally open contacts connected in parallel with said indicator lamp;
f. a starting switch connected between said battery and a second set of normally closed contacts, which is connected to a voltage coil of a starting motor circuit and to a voltage detecting coil, and wherein said voltage detecting coil is connected between said second set of normally closed contacts and a cathode of a diode, an anode of said diode being connected to the neutral point of said dynamo coils of said generator, and wherein said voltage detecting coil is coupled to said first and second sets of contacts, so as to respectively close and open said sets in response to the detection of a voltage from said diode.
2. A device for protecting a starting means in an internal combustion engine as claimed in claim 1, wherein an iron core for said voltage detecting coil, fixed contacts of said first and second sets and a mounting means are all mounted on a common supporting bracket, said iron core beingplaced between said fixed contacts of the first and second sets and said fixed contacts of said second set being placed between said iron core and said mounting means; a
an angular part of an L shape armature is fixed on the t of's 'd mo n'n eans throu h l t' 'pl te, a fi rst 313 02 851 armature be mg e xt c ari e fi over said iron core and a second end thereof being extended between the iron core and the mounting means;
a movable contact of said first set is placed on the