Driving mechanism

Abstract

Claims

Nov. 13, 1945. I J, ORRILL 2,388,700- DRIVING MECHANISM Filed Dec. 29, 1942 Irfiventot: Wayne J, Merrill, ' b fi y I /Attorney Patented Not 13, 194s UNITED STATES PATENT orrloa Wayne J. Merrill, Fort-Wayne, Ind., asslgnor to -General Electric Company, a corporation of New York Application December 29, 1942, Serial No. 410.466 13 Claims. (our-291) I h Y a spur gear l3 isiormed- Torque is adapted to My invention relates to driving mechanisms and particularly to a driving mechanism in which a unit is. arranged to provide a driving connection between driving and driven shafts and is adapted to limit the torque transmitted through the driving connection between these shafts to a predetermined safe operating value. An object of my invention is to provide an improved driving mechanism arranged to provide a driving connection between" driving and driven shafts and also to limit the torque transmitted through the driving connection to a predetermined value'. Another object of my invention is to provide a driving mechanism arranged to form a driving connection between driving and driven shafts with an arrangement for limiting the torque 'transmitted through the driving connection to a predetermined value and to prevent the formation of the driving connection after it has been released except after a reversal'of the driving shaft. I A further object of my invention-is to provide an improved driving mechanism to provide a driving connection between .a driving and a driven shaft when the driving shaft is operating, to release the driving connection when the source of power connected to the driving shaft larity in the claims annexed to and forming part of this specification. In the drawing, Fig. l is a schematic illustration of a driving mechanism including a planetary gear system embodying my invention; Fig. 2 is a plan view of a part of the mechanism shown in Fig. 1 illustrating the arrangement of a clutch locking key; Fig. 3 is a sectional end view taken along line 33 of Fig. 1; and Fig. 4 is a schematic illustration of the driving system shown in Fig. 1, together with the driving motor and associated switching devices. Referring to the drawing, I'have shown a driving mechanism in which a source of power such as an electric driving motor is provided with a field exciting winding i arranged to excite a rotatable member or armature It provided with a driving connection to a drive shaft l2 on which be transmitted from the driving motor shaft l2 to a driven shaft member it through a planetary gearing in which the spur gear I3 is arranged as the driving sun gear of the gear system. A ring gear I5 is rotatably supported by a bearing [6 about the drive shaft 12 and is provided with internal gear teeth ll arranged in mounted on bearings 19 about stub shafts 20 supported by a planet cage 2i formed on the driven shaft i4. Torque is adapted to be transmitted from the drive shaft i2 and the sun gear l3 to the driven shaft I4 through the planet gears i8 when the ring gear l5 is held stationary. An arrangement is provided for forming this driving connection by holding stationary the ring gear it when the driving motor is in operation and to provide for the release of this driving connection both when the torque transmitted through the gear system exceeds a predetermined safe operating value and when the driving motor is not energized. This is obtained by providing a set of external gear teeth 22 on the ring gear it arranged in engagement with a load limiting and release gear 23 formed on a rotatably supported auxiliary shaft 25. The shaft M is provided with an extension 25 about which' a pair of spring clutches 25 and 21 is arranged. The outer end 28 of the spring clutch it is secured in an opening in a shoulder 29 formed on the shaft 2 2i and the outer end (it of the spring clutch ii is secured in an opening near the end of the shaft extension 25. These two spring clutches are arranged within a clutch sleeve ill which is mounted about a stationary supporting bearing 32 and is provided with a pair of projections 33, each of which is resiliently biased to a centered position by a pair of preloading springs 35. In order to obtain a positive operation of the spring clutches i6 and ill, a clutch operating stop pin or locking key 35 is arranged to project between the adjacent inner free ends 36 and 31 of the spring clutches 26 and 21, respectively. This pin 35 is formed with a relatively narrow operating end portion 38 4| of an elongated slot in an outer sleeve 42. When the operat- This sleeve 42 is mounted on the shoulder 23 of the shaft 24 and forms a relatively high friction rotatable flt therewith. The pin 35 is adapted to be biased into its clutch operating position, as shown in Fig. 1, by a carrying finger 43 which is formed with an elongated slot 44 which extends about and forms a sliding fit with the head of the pin 35. This finger 43 is rigidly secured to an operating arm 45 pivotally supported by a pivot pin 46 and resiliently biased by a spring 41 away from the clutch sleeve 3|, so as resiliently to bias the operating finger 35 into its inoperative position out of the slot portion 4| and the slot 33 of the sleeves 42 and 3|, respectively. An electric solenoid operated release device is provided to bias the operating arm 45 toward the clutch sleeve 3| to bias the finger 35 into its operating position. This release device includes an armature 48 connected to the operating arm 45 and arranged to be operated by an electromagnet having a core 49 of magnetic material and an operating coil 50 electrically connected in series with the driving motor armature II. In this manner the coil 5|) is energized whenever the motor armature is energized and acts to bias the armature 48 and the operating arm 45 into operating position, and when the motor armature II is deenergized the coil 50 also is deenergized and the spring 41 biases the operating arm 45 to its inoperative position and releases the driving connection whenever the driving motor :is not in operation. When the coil 50 is energized and the arm 45 is biased toward the clutch sleeve 3|, so as to bias the operating finger 35 into the slot portion 4| and the slot 39 of the sleeves 42 and 3|, respectively, the mechanism is in its operating or locked position. In this position, when torque is transmitted to the sun gear l3 by the drive shaft |2, the planet gears l8 rotate about the shafts and exert a torque on the ring gear I 5 and the planet cage 2|. The ring gear l5 transmits this torque to the loading gear 23 which transmits the torque to the spring clutches 26 and 21, respectively, through their connections 28 and 3|] to the shaft 24. This tends to turn the spring clutches 26 and 21 which causes one of the free ends 36 and 31 thereof to engage the stop pin portion 38, which produces engagement of the corresponding spring clutch 26 or 21 by its expansion against the inner cylindrical surface of the clutch sleeve 3|. Engagement of either of the clutches transmits the torque through the clutches to the sleeve 3|, and if the torque does not exceed a predetermined safe operating value, the springs 34 hold the clutch sleeve 3| in centered position and thereby hold stationary the clutches 26 and 21 and the shaft 24. This prevents rotation of the gear 23 and consequently holds stationary the ring gear I5 and causes the planet gears l1 to rotate about the sun gear l3 and transmit torque to the driven shaft i4. If the torque which is transmitted through this driving connection exceeds a predetermined value, the spring clutches 26 and 21 will tend to turn the clutch sleeve 3| against the centering action of the springs 34 and this will cause tapered wedge surfaces 5| on the sides of the slot portion 4| in the sleeve 42 to contact the sides of the widened portion 40 of the stop pin, thereby tending to lift the stop pin out of the slots 39 and 4|. Furtheras seen in Fig, 3, and bias the operating arm 45 upwardly against the biasing action of the solenoid armature 48. This will lift the operating finger 43 which in turn will lift the pin 35 out l of the slot 39 formed in the clutch sleeve 3| and will thereby release the engagement of the inner free ends 38 and 31 of the spring clutches 26 and 21 from engagement with the narrow portion 38 of the stop pin 35. This releases the driving connection formed by the clutches 26 and 21 between the relatively stationary clutch sleeve 3| and the shaft 34 and permits the loading gear 23 to rotate. This releases the ring gear l5 and permits rotation thereof about its supporting bearing l6, thereby releasing the driving connection between the drive shaft l2 and the driven shaft |4. With this arrangement, the load on the gearing system is released whenever the torque transmitted thereby exceeds a predetermined value. It is also desirable that the driving motor should be stopped when the driving connection is released in order to prevent damage to the driving motor and the gears which rotate without transmitting load when the driving connection is released due to overload. This is obtained by providing a load releasing limit switch which is operable by the clutch sleeve 42 when the shaft 24 is released and is rotated by the torque transmitted thereto by the gear 23. To obtain this operation, a limit switch trigger 53 is secured to the sleeve 42 and is adapted to turn with the sleeve 42 to a limited extent due to the rotatable frictional fit between the sleeve 42 and the shoulder 29 of the shaft 24. Thus, when the pin 35 is lifted by the action of the cams 52 to release the load on the gearing system, the lower end of the pin 38 is allowed to extend through a relatively narrow portion 54 of the elongated slot 40 in the sleeve 42 and is prevented from extending more, this turning ofthe sleeve 3| will cause downwardly into the slot 39 of the sleeve 3| by engagement of the lower'edges 55 of the wide portion 40 of the pin 35 with the outer cylindrical surface of the sleeve 42. This permits a limited rotation of the sleeve 42 with the shaft 24 on rotation of this shaft when the driving connection is released, and the limit switch trigger 53 is arranged to engage one or the other of a pair of operating fingers 56 of a pair of limit switches 51 connected in series with the circuit of the motor armature A reversing switch 58 also is connected in the circuit of the driving motor armature H such that the motor armature can be energized in different directions relative to the energization of the field exciting winding II in order to reverse the direction of rotationof the driving motor. Thus, if the spring clutches 26 and 21 release the driving connection between the drive shaft l2 and the driven shaft I4, the load limit switch trigger 53 turns to a limited extent and biases one of the switch fingers 56 so as to open the series connected switches 51 and deenergizes the electric driving motor, thus stopping the operation of the motor and its associated driving mechanism. Since the switches 51 are connected in series with the circuit of the armature it is impossible to start the motor after it has been stopped in this manner without reversing the direction of rotation of the driving motor, so as to turn the limit switch operating trigger 53 in a direction opposite to that which caused it to open one of the switches 51. Reverse rotation of the driving motor is obtained by connecting the reversing switch 58 so as to reverse the connections of the armature H to thesource of electrical power supply and then completing the armature energizing circuit by closing a starting switch 59. This closes the circuit of the armature ll through a starting resistance 60 and prevents damage to the operating mechanism by causing the motor to start up at a greatly reduced torque until the switches 51 have been closed by operation of the limit switch trigger 53. Thisreverse rotation of the driving motor I I transmits a reverse torque to the loadinggear 23 through the planetary gearing and causes the clutch sleeve 42 to turn in an opposite direction from that in which it turned to stop the operation of the mechanism and causes the lower edges 55 of the clutch operating pin 35 to slide downwardly over the tapered surface of the slot 4| to permit the pin 35 to return to a clutchoperating position with the relatively narrow portion 38 extending through the opening 39 in the sleeve 3|, so as to engage one of the free ends 36 and 31 of the spring clutches 26 and 2'! and again provide a driving connection through the planetary gearing by holding stationary the loading gear 23 and the ring gear i5. Thus, this driving mechanism provides an arrangement which forms a driving connection between a driving shaft and a driven shaft responsive to the energization and to. the operation of the driving motor and automatically limits the torque transmitted through this driving connection to a predetermined safe operating value and also provides for stopping the operation of the driving mechanism when this predetermined torque has been exceeded.- Furthermore, the construction of the load releasing clutch provides for preventing the biasing of the operating pin into its operating position to prevent the formation of a driving connection when the driving motor is deenergized or after this driving connection has been released due tooverload except by a reversal of the direction of. rotation of the driving motor. Such reversal assures against impressing a destructive torque on the driving mechanism and tends to operate the driven mechanism to a safe position after the excessive torque has been released. 7 While I have illustrated and described a particular embodiment of my invention, modifications thereof will occur to those skilled in the art. I desire it to be understood, therefore, that my invention is not .to be limited to the particular arrangement disclosed, and I intend in the appended claims to cover all modifications which do not depart from the spirit and scope of my invention. What I claim as new and desire to secure by Letters Patent of the United States is: .1. A driving mechanism including a driving means and a driven member, means including a spring clutch responsive to operation of said driving means for providing a driving connection between said driving means and said driven member below a predetermined torque when said driving means is in operation and for releasing said driving connection above said predetermined torque, and means for controlling the operation of said spring clutch for preventing formation of said driving connection after said release thereof due to a torque above said predetermined torque except by reversalof said driving means. 2. A driving mechanism including a driving means and a driven member, means including a clutch responsive to operation of said driving means for providing a driving connection between said driving means and said driven member below a predetermined torque when said driving means 7 and means for controlling the operation of said clutch for preventing formation of said-driving connection after said release thereof due to a torque above said predetermined torque except by reversal of said driving means. 3. A driving mechanism including an electric driving means and a driven member, means in cluding a clutchresponsive to operation of said electric driving means for providing a driving connection between said driving means and said driven member below a predetermined torque when said driving means is in operation and for. releasing said driving connection above said predetermined torque, means responsive to said release of said driving connection for stopping operation of said driving means, and means responsive to energization of said electric drive means for preventing the engagement of said clutch to prevent formation of said driving connection after said release thereof except by reversal of v said driving means. 4. A driving mechanism including an electric driving motor means, a driven member, spring clutch means operable in response to energization of said driving means for providing a driving connection between said driving means and said driven member below a predetermined torque when said driving means is energized and in operation and for releasing said driving connection above said predetermined torque, means responsive to said release of said driving connection for deenergizing said electric driving motor, and means responsive to energization of said electric motor for preventing formation of said driving connection. when said driving means is deenergized and also after said release thereof except by reversal of said electric driving motor. 5. A driving mechanism including an electric driving motor means, a driven member, means includinga spring clutch responsive to energization of said driving means for providing a driving connection between said driving means and said driven member below a predetermined torque when said driving means is'in operation and for releasing said driving connection above said pre-' determined torque, means responsive to said release of said driving connection for deenergizingsaid electric driving motor means, and means responsive to energization of said electric motor means for preventing the engagement of said clutch after release due to a torque above said predetermined torque to prevent formation of said driving connection after said release thereof except by reversal of said electric driving motor means, said means responsive to energization of said driving means being arranged to release said clutch when said driving means is deenergized. 6. A driving mechanism including a driving means, a driven member, means including a planetary gearing for providing a driving conholding stationary said second gear below a predetermined torque to provide said driving connection and for releasing said driving connection above said predetermined torque, and means including a limit switch operable in response to said release of said driving connection for deenergizing said electric driving means. 7. A driving mechanism including a driving means, a driven member, ,means including a planetary gearing for providing a driving connection between said driving means and said driven member, said planetary gearing including a gear arranged to be driven by said driving means, a second gear, planet gears arranged in engagement with said first-mentioned and second gears and rotatably supported by said driven member, a load connecting and releasing means including a spring clutch operable in response to energization and operation of said driving means for holding stationary said second gear below a predetermined torque to provide said driving conassenoo connection between said driving means and said driven member, said planetary gearing including a sun gear arranged to be driven by said driving nection and for releasing said driving connection above said predetermined torque, means operable in response to said release of said driving connection for stopping operation of said driving means, and spring biased means for preventing formation 01. said driving connection after said release thereof except by reversal of said driving means. 8. A driving mechanism including a driving means, a driven member, means including a planetary gearing for providing a driving con nection between said driving means and said driven member, said planetary gearing including a gear arranged to be driven by said driving means, a second gear, planet gears arranged in engagement with said first-mentioned and second gears and rotatably supported by said driven member, a load connecting and releasing means including a spring clutch responsive to energization and operation of said driving means for holding stationary said second gear below a predetermined torque to provide said driving connection and for releasing said driving connection above said predetermined torque, means operable in response to said release of said driving connection for stopping operation of said driving means, means for preventing formation of said driving connection after said release thereof except by reversal of said driving means, and means for resiliently biasing said release means to release said driving connection. 9. A driving mechanism including an electric driving motor means, a driven member, means including a planetary gearing for providing a driving connection between said driving means and said driven member, said planetary gearing ineluding a gear arranged to be driven by said driving means, a second gear, planet gears arranged in engagement with said first-mentioned and second gears and rotatably supported by -said driven member, a'load connecting and releasing means including a spring clutch responsive to energization of said electric driving means for holding stationary said second gear below a predetermined torque to provide said driving connection and for releasing said driving connection above said predetermined torque, means including a limit switch operable in response to said release of said driving connection for deenergizing said electric driving motor, and means for preventing formation of said driving connection after said release thereof except by reversal of said driving motor. 10. A driving mechanism including an electric driving means, a driven member, means including a planetary gearing for providing a driving. ring gear to provide said driving connection between said driving means and said driven member, means including a clutch operating stop pin for engaging said spring clutch to provide said driving connection when said pin is in operating position, resilient means for biasing said pin towards a released clutch position, means including an operating member for actuating said stop pin away from said clutch operating position for releasing said driving connection above a predetermined torque through said driving connection, means operable in response to said release of said connection for stopping operation of said driving means, and means including an elementfor preventing said pin from being biased into said operating position for preventing formation of said driving connection after said release thereof excent by reversal of said driving means. A driving mechanism including an electric driving means, a driven member, means including a planetary gearing for providing a driving connection between said driving means and said driven member, said planetary gearing including a sun gear arranged to be driven by said driving means, a ring gear, planet gears arranged in engagement with said sun and ring gears and rotatably supported by said driven member, a load connecting and releasing means including a spring clutch responsive to energization of said electric driving means for holding stationary said ring gear to provide said driving connection between said driving means and said driven member, means including a clutch operating stop pin for engaging said spring clutch to provide said driving connection when said pin is in operating position, means including a resiliently biased operating member for actuating said stop pin away from said clutch operating position for releasing said driving connection above a predetermined torque through said driving connection, means operable in response to said release of said driving connection for stopping operation of said driving means, and means including an element for preventing said pin from being biased into said operating position for preventing formation of said driving connection after said release thereof except by reversal of said driving means. 12. A driving mechanism including an electric driving motor means, a driven member, means including aplanetary gearing for providing a driving connection between said driving means and said driven member, said planetary gearing including a gear arranged to be driven by said driving means, a second gear, planet gears arranged in engagement with said first-mentioned and second gears and rotatably supported by said driven member, a load connecting and releasing means includinga spring clutch responsive to energization of said electric driving means for holding stationary said second gear to provide said driving connection between said driving means and said driven member, means including a clutch operating stop pin for engaging said spring clutch to provide said driving connection when said pin is in operating position, means including a resiliently biased operating member for actuating said stop pin away from said clutch operating position for releasing said driving connection above a predetermined torque through said driving connection, means operable in response to said release of said driving connection for deenergizing said electric driving motor, and means including an element for preventing said pin from being biased into said operating position for preventing formation of said driving connection after said release thereof except by reversal of said driving motor. 13'. A driving mechanism including an electric driving motor means, a driven member, means including a planetary gearing for providing a driving connection between said driving means and said driven member, said planetary gearing including a gear arranged to be driven by said driving means, a second gear, planet gears arranged in engagement with said first-mentioned and second gears and rotatably supported by said driven member, a load connecting and releasing means including a spring clutch responsive to energization of said electric driving means for holding stationary said second gear to provide said driving connection between said driving means and said driven member, means including a clutch operating stop pin for engaging said spring clutch to provide said driving connection when said pin is in operating position, means including resiliently biased operating member for actuating said stop pin away from said clutch operating position for releasing said driving con- WAYNE J. MORRILI...

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