US2947891A - Charged spring starters - Google Patents

Description

Aug. 2, 1960 c. e. surrs CHARGED spams STARTERS lrzl/entor' Chauncey 6. (50/25, by )Q/ 4 W Filed May 15, 1957 iilnited grates Patent Office 2,947,891 Patented Aug. 2, 1960 2,947,891 CHARGED SPRING STARTERS Chauncey Guy Suits, Schenectady, N.Y., assignor to General Electric Company, a corporation of New York Filed May 13, 1957, Ser. No. 658,690 6 Claims. (Cl. 31(l-41) This invention relates to charged spring starters and, more particularly, to an arrangement for storing energy of a rotating apparatus during its deceleration or rundown period, to be thereafter utilized as energy available for starting the apparatus.

Electric motors and similar rotary apparatus generally require a large current for starting rotation and thereafter utilize a much lower current for normal operating conditions. Such large starting currents frequently cause disadvantages or problems in the associated electrical circuit. One of these problems is the fading of light in the same circuit. That is, when the same power source is employed to supply an electrical current to both lighting equipment and electrical rotating apparatus, the high current necessary for starting the apparatus reduces temporarily the amount of current available for sustaining constant intensity lighting. The result is a fading of the light source. This light fading is especially prevalent where there is an increased use of domestic appliances of the motor driven type. In the average home in too many instances proper or ample electrical circuits, i.e., wires or conductors of a large enough size, are not available .to conduct or carry the temporarily large current.

During intermittent operation of electrical apparatus, such light fading and lessened current to other electrical apparatus may be not only highly objectionable for good lighting, but also deleterious to other apparatus employing the same power source. It follows that when several electrical rotary devices are involved, intermittent operations may coincide with each other, so that the combined starting currents are too large for the safety devices in the electrical circuit and result in fuse failure or circuit interruption. For example, an electric motor of A horsepower capacity rotating at 1750 rpm. may utilize approximately 12 amperes on starting, and thereafter operate at running speed on approximately 4 amperes. Two or more such motors starting coincidentally can seriously overload an electrical circuit.

It is an object of this invention to provide an arrangement to reduce the starting current requirements on rotary electrical devices.

It is another object of this invention to provide a device to store the energy of an electrical rotary apparatus during the run-down or deceleration period for sub sequent utilization as starting energy.

It is a still further object of this invention to minimize light fading due to the high current requirements, upon starting, of an electrical motor and the like electrical rotary apparatus.

Further objects and advantages of this invention will be more apparent when taken in connection with the following description and the drawings.

Fig. 1 shows an energy storing device associated with the armature shaft of an electrical motor;

Fig. 2 is an end view of Fig. 1 showing the energy storing spring together with the electrical devices for operating this invention;

Fig. 3 discloses a view of Fig. 1 detailing the ratchet assembly; and

Fig. 4 discloses a schematic wiring diagram for the electrical operation of this invention.

Briefly described, this invention contemplates a charged spring device for rotating the shaft of rotary apparatus and includes in combination with the spring as the energy storing means, a pair of power transmitters or clutches one of which, a winding clutch, is employed to engage the spring to the rotary apparatus for winding of tightening of the spring, while the other or second clutch releases the energy stored in the spring to rotate the apparatus. Electrical control devices including solenoids and a suitable time delay means are employed to couple the energy storing spring to the rotating apparatus during the deceleration period to store energy. When the rotating apparatus is to be started subsequently, the spring is disengaged from the winding clutch and engages the second clutch to turn or rotate the apparatus to a predetermined speed at which current is supplied to the apparatus to provide normal running operation, or, if necessary, to continue the acceleration to normal running speed.

Fig. 1 shows a rotary apparatus in the form of a partial end section drawing of an electrical motor 1 which comprises a casing 2 and an end section 3 having a hearing 4 mounted therein. Within the housing 2 are positioned field coils 5 concentric with and surrounding a rotor 6. Rotor 6 includes a shaft 7 supported at one end in bearing 4, and at the oppoiste end in a further bearing, not shown. A spring drum 8 is slidably and rotatably mounted on the shaft 7 between the rotor 6 and the bearing 4 by means of a sleeve bearing 9. Sleeve bearing 9 may be of the self-lubricant or lubricant impregnated variety or may be lubricated by various forms of lubrication well known in the art. Drum 8 comprises a first clutch plate 10 rotatably mounted on bearing 9 by means of sleeve 11'. Clutch plate 10 includes a suitable clutch facing 12 which may be of the friction on gear type and which faces the rotor 6. A second clutch plate 13 spaced from clutch 10 is afiixed to bearing 9 by any well known means such as the threaded engagement shown at 14; Clutch plate 13 also includes a suitable friction or gear clutch facing 15 which faces bearing 4. Between the clutch plates 10 and 13 and concentric with the shaft 6'is positioned a coil spring 16. In Fig. 2, spring 16 is shown in one form as a spiral coil of strip metal and is affixed at one end to clutch plate 10 and sleeve 11 by a lip 17 in slot 18 of sleeve 11, and thereafter maintained in position by a screw 19. The other end of spring 16 is afiixed to clutch plate 13 by encircling a pin 20 provided on clutch plate 13. A third clutch plate 21- is fixedly mounted on shaft 7 between the rotor 6 and the clutch plate 10. Clutch plate 21 includes a clutch facing 22 which also may be of the friction or gear type and which is adapted to be engaged by the clutch 12. Between the clutch plate 13 and the bearing 4, a fourth clutch plate 23 is fixedly mounted on shaft 7 and also includes a clutch facing 24 of the friction or gear type adapted to be engaged by clutch facing 15 on clutch plate 13.

In order to control rotation of the drum assembly 8, clutch plate 13 is provided with teeth 25 on the periphery thereof, as is best shown in- Fig. 2'. Teeth 25' are engaged by a stop member 26 which, in turn, is fixedly mounted on casing 2'. Clutch plate 10 is prevented from rotation in one direction and permitted to rotate in the opposite direction by means of a ratchet device 27. Device 27, as more clearly indicated in Fig. 3, includes ratchet teeth 28 formed on the outer periphery of clutch plate 10 and engaged by a movable ratchet tooth 29. Ratchet tooth 29 is biased into engagement with teeth 28 by means of a spring 30 carried in a yoke support 31.

Referring now to Fig. 2, support 31 is shown as mountedfor oscillatory movement about a pin 32 which is affixed to the stop member 26 and, in turn, to the casing 2. Yoke 31 surrounds drum 8 and is adapted to move the drum 8 axially along shaft 6, by means of a pair of bushing members 33 which are positioned at diametrically opposite points, each 90 degrees from pin 32. Bushings 33 include short shafts 34, extending from heads 35 and positioned within openings 36, Fig. 1, in yoke 31. Heads 35, in turn, are positioned between clutch plates and 13, such that oscillatory movement of the yoke causes the bushing heads 35 to engage the inner surfaces of one or the other clutch plates 10 and 13 to move drum 8 axially along the shaft. Referring again to Fig. 1, it may be seen from this arrangement that upon interruption of current to the motor 1 which is assumed to rotate counterclockwise, facing end 3 of motor 1, yoke 31 may be moved toward the rotor 6, and thereby, through the action of bushings 33 on clutch plate 10, moves clutch 12 into engagement with clutch 22. Thereupon, rotor 6 is rotatingclutch plate 10 which, in turn, tightens or winds spring 16 which is attached to clutch plate 10 at sleeve 11. The tightening or winding of the spring is made possible through the action of stop member 26 in engagement with teeth 25 preventing clutch plate 13 from rotation. At the end of the wind-up or tightening period, ratchet device 27 prevents the clutch plate 10 from rotating in a clockwise direction as viewed from end 3 and thus unloading the spring. At this point both clutch plates 10 and 13 are restrained from rotation and maintain therebetween a tightened or wound spiral spring 16 whose stored energy may be then employed to rotate shaft 6 upon starting of the motor.

In order to utilize this energy, yoke 31 is moved away from the rotor 6 toward bearing 4 and, through the action of bushings 33 on clutch plate 13, drum 8 is moved toward clutch plate 23, and clutches and 24 are engaged. Movement of drum 8 along shaft 6 disengages stop member 26 from teeth so that spring 16, in unwinding, rotates fixed clutch plate 23 and rotor 6 in the same direction that the rotor rotates during normal operation.

In Fig. 1, yoke 31 includes a three-part depending arm member 37. Arm member 37 is maintained between a pair of biasing members or springs 38 and 39 so that the drum member 8 with the clutch facings 12 and 15 are not engaged with clutch faces 24 and 22 on plates 23 and 21. The springs 38 and 39 permit the yoke 31 to be moved in either a fore or aft direction and to be returned by the springs 38 and 39 to an unengaged position of the clutches. Any suitable control means may be employed to move yoke 31. In the preferred form of this invention, as more clearly shown in Fig. 2, a pair of solenoids 40 and 41 together with a suitable time delay relay means 42 co-operate to perform the desired sequence of operation. Solenoid 40 is of a pushing type with an initially retracted'plunger and, when energized, serves to push yoke 31 toward rotor 6. Solenoid 41 is a pull solenoid and when energized serves to pull yoke 31 toward bearing 4. 7

Referring now to Fig. 4, there is shown a circuit including solenoids 40 and 41, time delay relay means 42, motor 1 and a switch 43 which controls the current from a suitable source ofpo'wer, not shown, to motor 1. When motor 1 is operating under normal conditions and switch 43 is moved to the OE position, arm 44 engages contact 45 to energize push solenoid 40, moving yoke 31 and drum 8 toward the rotor 6, and thereby engaging clutches 12 and 22. The run-down or coasting inertia of the rotor rotates clutch plate 10 to which spring 16 is attached and tightens or winds the spring 16. At the finish of coast-down, ratchet tooth 29 prevents spring 16 from unwinding.

When switch 43 is moved to the on position, 44

engages contact 46 to energize pull solenoid 41 and pull yoke 31 and drum 8 toward bearing 4. During this movement of drum 8, stop member 26 becomes disengaged fro'm teeth 25, just prior to the clutch facings 15 and 24 becoming engaged, thus permitting the spring 16 which is afiixed to .clutchplate 13 to rotate clutch plate 13 and clutch plate 23 and rotate shaft 7. When the shaft has reached the maximum rotating speed available from the energy stored in spring 16, time delay relay 42 operates to supply current to the motor to continue its acceleration or to maintain its normal speed. Switch 43 may be of any design capable of performing the desired sequence of operation. In one form of this invention switch arm 44 is spring biased to maintain a central or neutral off position between co'ntacts 45 and 46.

Movement of the switch arm 44 to engage contact 45 completes the off circuit to charge the spring 16. When the operator releases switch arm 44, spring 47 returns arm 44 to the neutral position as shown in Fig. 4, whereby the charge solenoid 40 is deenergized and springs 39 and 40 return yoke 31 also to the neutral position shown in Fig. 1. For the on position where arm 44 engages contact 46, spring 47 is inoperative and permits the on circuit to be maintained.

Various arrangements of switching means and time delays together with other clutching means may be satisfactorily applied to this invention with equal results.

While other modifications of this invention and variations of apparatus which may be employed within the scope of this invention have not been described, the invention is intended to include all such as may be embraced within the following claims.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A rotary apparatus starter comprising in combination, a spring energy storing device operatively connected to said rotary apparatus, a first clutch to energize said spring to said rotary apparatus to' store energy in said spring, and a second clutch to engage said spring to said rotary apparatus to initiate acceleration of said rotary apparatus.

2. A charged spring starter for electric motors comprising in combination, a spring associated with the shaft of said motor, a first clutch to engage said spring to said motor for winding thereof, means to maintain said spring in the wound'condition, and a second clutch adapted to engage saidspring to said shaft for acceleration thereof.

3. A charged spring starter for electrical motors comprising in combination, a drum assembly slidably and rotatably mounted on the shaft of said motor, said drum assembly comprising first and second'spaced apart clutch plates and a spiral spring therebetween connected one end to each of said first and second clutch plates, a third clutch plate fixedly mounted on said shaft and adapted to be engaged by said first clutch plate, a fourth clutch plate fixedly mounted on said shaft and adapted to be engaged by said second clutch plate, shifting means to move said drum assembly for engagement of said first and third clutch plates to wind said spring through rotation of said motor, stop means to prevent rotation of said second clutch plate during spring winding, means to prevent rotation of said first clutch plate in one direction at the end of spring winding operation, and means to shift said drum for engagement of said second and fourth clutch plates and release of said stop member for rotation of said motor shaft by said spring.

7 4. Motor control means for the invention as claimed in claim 3 comprising in combination, a first solenoid operable upon interruption of the circuit to said motor to engage said first and third clutch to wind said spring, a second solenoid operable upon establishing a circuit to said motor to engage said second and said fourth clutch to rotate the motor shaft through the action of said spring, and time delay means to complete the electrica-l circuit to said motor after spring rotation of the shaft thereof.

5. In a charged spring starter for an electric motor having a casing, 1a field coil in said casing, a pair of spaced apart hearings in said casing and a shaft mounted rotor supported between said bearings and concentric with said field coil, the combination comprising, a drum assembly, said drum assembly including first and second clutch plates mounted on said shaft in spaced apart relationship between said rotor and one of said bearings, a spring between said first and second clutch plates and affixed at its ends to a different plate, a third and fourth clutch plate affixed to said shaft one on each side of said drum assembly, solenoid means operable upon interruption of the circuit to said motor to engage said first and third clutch plates to wind said spring during motor deceleration, a tooth member to prevent rotation of said second clutch during Winding of said spring, a ratchet member to prevent rotation of said first clutch assembly after spring winding, a solenoid operable on current being supplied to said motor to engage said second and fourth clutches to release said tooth member for shaft rotation through the action of said spring, and time delay means to establish circuitry to said motor after rotation of said shaft by said spring.

6. In a charged spring starter for electric motors having a rotating shaft mounted armature supported between a pair of spaced apart bearings, the combination comprising, a drum assembly slidably and rotatably mounted on said shaft between the rotor and one of said bearings, said drum assembly including first and second friction clutches having a spiral strip spring concentric with said shaft between said first and second friction clutches, said spring being attached at one end to said first clutch and at the other end to said second clutch, a third friction clutch adapted to be engaged by said first friction clutch, a fourth friction clutch adapted to be engaged by said second friction clutch, first solenoid means to move said drum along said shaft for engagement of said first and third friction clutches for winding of said spring through deceleration of said motor, second solenoid means to move said drum along said shaft for engagement of said second and fourth friction clutches to rotate said shaft through the action of said spring, and biasing means to maintain said drum assembly in a position where the said first and third, and second and fourth clutches are disengaged.

References Cited in the file of this patent UNITED STATES PATENTS 407,844 Thomson July 30, 1889 1,289,788 Jackson Dec. 31, 1918 1,788,062 Martin Jan. 6, 1931 2,018,515 Doeg Oct. 22, 1935 2,589,453 Storsand Mar. 18, 1952

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