US3011100A - Mechanically held movement and magnetic motor therefor - Google Patents

Description

Nov. 28,, 1961 F. P. SPINELLI ET AL MECHANICALLY HELD MOVEMENT AND MAGNETIC MOTOR THEREFOR Filed Feb. 20, 1958 2 Sheets-Sheet 1 INVENTORS: FRANK l SP/IVELL/ BYJ'AMES 7 COL/Z ,4 TTaQ/VEY Nov. 28, 1961 F. P. SPINELLI ET AL 3,011,100

MECHANICALLY HELD MOVEMENT AND MAGNETIC MOTOR THEREFOR Filed Feb, 20, 1958 2 Sheets-Sheet 2 INVENTORS: FkAA K R JP/A/ELL 74/ 755 7. COL/Z BY I ATTA/EYS United States Patent MECHANICALLY HELD MOVEMENT AND MAGNETIC MOTOR THEREFOR Frank P. Spinclli, Teaneck, and James T. Coliz, New

Providence, N.J., assignors to Automatic Switch Co., Florham Park, N.J., a corporation of New York Filed Feb. 20, 1958, Ser. No. 716,487

8 Claims. (Cl. 317123) This invention relates generally to actuating devices and has particular reference to motors of the rotary electromagnetic type.

It is a general object of the invention to provide an improved magnetic motor adapted to serve as a source of motive power to move or shift an object acted upon (such as an electric switch element or the like) into one or the other of two positions, and to hold it there. The actuator is of the kind in which the primary element is a solenoid armature adapted to pivot on its axis through a limited arc, the movement being sufficiently forceful, rapid and reliable to impart the desired motion to an object linked in appropriate driven fashion to the shaft on which the rotor is mounted. The device is primarily intended as a source of power for operating electric switches of various kinds, but is equally useful for a wide variety of other purposes, wherever positive, accurate, speedy and reliable movement of a driven element is desired.

The motor is designed for control by electrical means operated either manually or automatically in the proximity of the device or at a remote point.

For illustrative purposes, the invention will be described in an embodiment intended for the operation of the movable element of a bus-bar switch of known kind, to throw and mechanically retain the switch in either open or closed condition, but it will be understood that the invention is not restricted to any such specific purpose.

One of the more particular objects of the invention is to provide an actuating device of the type described in which movement of the pivoted armature may be effected by a relatively small amount of electrical energy operating only over a very short period of time; in which the rotor may be mechanically held in its opposite rest positions without the application of any electrical energy at all; and in which the same magnetizing means is adapted to produce movement of the rotor in each direction. To achieve these results, the rotor is associated with a mag netizable stator in such a way that it moves between angularly spaced rest positions symmetrical on opposite sides of a medial position of minimum reluctance, and a resilient means of special design is provided for constantly urging the rotor toward whichever of its rest positions it is nearest. The parts are so designed and the operation is so controlled that a momentary magnetization of the stator serves to initiate movement of the rotor force that remains substantially constant under deflection,

as the resilient means acting upon the rotor. Each spring is interposed between the rotor and its housing in such a way that the anchorage ofthe spring to the housing is aligned with the magnetic axis of minimum reluctance. Preferably the springs are used in pairs. The use of constant-force springs has important advantages in a magnetic motor assembly, over conventional compression or tension springs, as will be pointed out hereinafter.

Another feature of the device lies in the provision of a new mechanical locking or holding means of simplified but highly effective character whereby reverse actuation of the rotary armature by the driven part or element,

either inadvertently or deliberately attempted, is positively prevented.

" A further feature of the design resides in the almost complete balance that is achieved whereby the power required for operation can be unusually small, and wear and tear are reduced to a minimum, thus imparting staunchness and long-life characteristics to the assembled unit.

Because of the features of structure and design, the sizes of the electrical components and other operating parts can all be kept to a minimum and the device as a whole can be made unusually compact in relation to the load imposed upon it. The assembly of elements is such that it lends itself admirably to miniaturization, as a result of which the invention may be applied advantageously to devices of widely different sizes and purposes. Whatever its size, the device is mechanically and electrically practicable, and may be manufactured at relatively low cost and operated economically and reliably for long periods of time.

One way of achieving these general objects and advantages, and such other objectives and benefits as may hereinafter appear or be pointed out, is illustratively exemplified in the accompanying drawings, in which FIGURE 1 is an elevational view of a magnetic motor assembly embodying the features of the invention, the driven shaft being broken away for the sake of compactness of illustration; 7

' FIGURE 2 is a cross-sectional view along the lines 2-2 of FIGURES 1 and 3;

FIGURE 3 is a cross-sectional view on the line 3-3 of FIGURE 2;

FIGURES 4, 5 and 6 arediagrammatic representations of the motor parts and its control circuit, showing successive stages during'one swing of the rotary solenoid armature; I

FIGURE 7 is an end view, in the direction 77 of FIGURE 1, the armature being in one of its rest positions;

FIGURE 8 is a viewsimilar to FIGURE 7, the armaturebeing in the opposite rest position;

FIGURES 9 and 10 are views along the line 99 of FIGURE 1, showing the special locking linkage in its extreme positions, corresponding to the armature positions of FIGURES 7 and 8 respectively;

. FIGURE 11 is a cross-sectional view along the line 11--11 of FIGURE 1; and p 0 FIGURE 12 is a view along the line 12-12 of FIG- URE 1.

An appropriate housing 20 encloses and supports a laminated magnetic core 21 provided with opposed mag netic poles 22 between which the rotary solenoid arma- Hire 23 is mounted for swinging movements on'a supporting shaft 24. The shaft 24 is centrally positioned between the poles 22, and the armature 23 is substantially cylindrical or drum-shaped, with the exception that the central region of the armature is formed with flattened faces 25. These faces are parallel to the magnetic axis, as shown in FIGURES 2 and 3, whenever the armature is in the intermediate position ofminimum reluctance during its wingfrom one of its rest positions to the other. -These opposite restpositions are indicated in FIGURES 4, 6 and 710.

Mounted on the shaft 24 at one end of the armature is a concentric plate 26 which moves with the armature at all times, by virtue of the interconnection between the eccentric pin 27 and a corresponding recess on the rear face of the plate 26. This interconnection between the plate 26 and the armature body 23 is desirable from a manufacturing standpoint, since the plate 26 and all the mechanism associated with it can be readily separated from the shaft 24, to which it is normally secured by a set screw (not shown).

At the opposite end of the armature there is a projecting eccentric pin 28, hereinafter to be referred to in greater detail, by means of which the power of the magnetic motor is transmitted to the element to be moved thereby. In the embodiment herein chosen for illustration this element has been depicted in the form of a switch arm 29 secured to and projecting radially from a driven shaft 30. The arm 29 carries the movable contact 31 of an electric switch, the fixed contact 32 being suitably mounted on a panel, or on a fixed part of the motor unit itself. The shaft 30 is adapted to be rocked to bring the movable contact 31 into the open position shown in FIGURE 11, or into a switch-closing position in which the contacts 31, 32 are in contact with each other.

It is to be understood that under certain circumstances the shaft 30 may carry a plurality of movable switch arms, and that the single arm 29 herein depicted is intended merely to be an illustrative representation of a driven element whose movements are brought about by the magnetic motor.

The electric circuit by means of which the motor operation is controlled is indicated in FIGURES 4-6. From a source of current 33 (which has been diagrammatically represented as a battery but which may obviously consist of any other source of electric power) a lead 34 extends to the energizing windings 35 associated with the magnet poles 22, then to an oscillatable member 36 having a pair of movable contacts 37 and 38 at its ends. The element 36 oscillates between the position shown in FIGURE 4 and that shown in FIGURE 6. The contact 37 is adapted to cooperate with a relatively fixed contact 39 in acircuit branch 46 whose opposite end is a fixed contact 41 of a control switch 42. The movable contact 38 is adapted to cooperate with a similar relatively fixed contact 43 in a circuit branch 44 whose opposite end is the contact 45 of the control switch 42. A movable switch arm 46 leading from the power source 33 is adapted to be moved between the position of FIGURE 4 and the position shown in FIGURES and 6.

Before describing the operation of the electric circuit, attention is directed to the right-hand end of FIGURE 1, and to FIGURE 12, in which a physical embodiment of the oscillatable part 36 of the electric circuit is represented. The element 36 is shown as a double-armed switch member rigidly secured to and oscillatable by the shaft 30. The fixed contacts 39 and 43 are represented as being secured to a panel or other supporting surface 47. A wire 48 establishes electrical connection between the movable contacts 37 and 38; and a wire 49 is shown connected to a fixed terminal 50 (indicated also in FIG- URES 46) from which an electrical connection (not shown) leads to the windings 35. The pivotally mounted member 36 has been shown as being secured to the shaft 30, which also supports the driven element 29. This isa matter of manufacturing convenience only, and the pivoted circuit-controlling element 36 may be oscillated by any other convenient means actuated by the armature during its swinging movements.

Assuming'the armature 23 to be in the rest position shown in FIGURE 4, a movement of the switch 46 to the position of FIGURE 5 will close a circuit through the contacts 37, 39 which will energize the windings 35 and thusattract the armature 23 toward the position of minimum reluctance, as indicated in FIGUREv 5. How ever, after the movement of the armature 23 has been initiated, and shortly before the armature reaches the medial position indicated in FIGURES 2 and 3, the contact 37 is lifted from the contact 39, thus breaking the circuit and deinagnetizing the poles. The armature 23 nevertheless continues its swinging movement to the opposite rest position shown in FIGURE 6, whereby the contacts 38 and 43 are closed in readiness for the subsequent actuation of the switch 46. Whenever the armature is to be moved back from the position of FIGURE 6 to that of FIGURE 4, the switch element 46 is moved to the position of FIGURE 4 again, whereby an energizing circuit through the magnet poles is established. The operation described is then repeated as the armature swings back to the position of FIGURE 4.

Opposing the motion of the armature at the start of each swinging movement, and assisting it at the conclusion of its swing, is a spring means of special character illustrated in FIGURES 7 and 8.

A first pair of bowed constant-force springs 51, 52, bowed in opposite directions as shown, is operatively interposed between the armature and the housing. The springs 51, 52 have a common anchorage 53 on the plate 26, this being in effect an anchorage to the armature 23. The opposite ends of the spring pair have a common anchorage 54 to the fixed housing 20. A similar pair of springs 55, 56 extend between an anchorage to the housing at 57 and an anchorage to the plate 26 at 58. The spring pair 55, 56 is diametrically opposed to, and symmetrical with relation to, the spring pair 51, 52.

Each of the springs 51, 52, 55 and 56 is of the kind whose force remains substantially constant during deflection. Each spring is an elastic device in the form of a helical coil which provides deflection through bowing of the coil, maintaining a substantially constant force resisting compression. 'The nature of the deflection is indicated in dot-and-dash lines in FIGURE 8. As the armature swings in a clockwise direction from the position of FIGURE 7 to that of FIGURE 8 the anchorages 53 and 54 come closer together, and the anchorages 57 and 53 make a similar approach toward each other, and then as the swing of the armature continues these anchorages separate once more, restoring the springs to the original state, as indicated in full lines in FIGURE 8. During the deflection of the springs, the resisting force imposed by them upon the moving armature is substantially constant. This is quite different from the action of conventional tension or compression springs, whose force increases as they are stressed. As a result, in the present device, the opposing torque of the spring arrangement is at its maximum at the ends of each swinging movement, and is zero at the intermediate position represented in d'ot-and-dash lines in FIGURE 8. The transition from maximum to zero torque is substantially linear in nature since it is only the leverage that diminishes, not the force of the spring or springs. As a result, a relatively low amount of electrical energy is required to initiate the movement of the armature during each of its swings. If ordinary springs were used, the energy would have to be great enough to overcome the increasing resistance of the spring as it is stressed.

It is to be noted that the housing anchorages 54 and 57 are aligned with the magnetic axis extending through the poles 22. This symmetry, coupled with the symmetry of each spring pair, and the symmetry of the opposite spring pairs themselves, creates a highly desirable balanced condition in the armature, minimizing friction, thus further reducing the energy required for operation.

The arm 59, projecting radially from the plate 26, is merely for the convenience of manually moving the armature, should this become necessary or desirable.

' At the opposite end of the housing 20 there is a Wall provided with an arcuate slot 60 through which the eccentric pin 28 extends. The ends of this slot constitute abutments which limit the swinging movements of the armature, A driven member 61 in the form of a lever of the first class is pivoted to the housing at 62 and is adapted to swing between the two rest positions indicated in FIGURES 9 and 10. The member 61 is provided with a longitudinal slot 63 with which the pin 28 engages, as a result of which the pivoted member 61 swings from the position of FIGURE 9 to that of FIGURE when the pin 28 moves in an arcuate path irom the position of FIGURE 9 to that of FIGURE 10. This occurs whenever the armature 23 swings from the position of FIGURES 7 and 9 to the opposite rest position shown in FIGURES 8 and 10. i

It is a feature of the invention to locate the pivot 62 in such a way that in each rest position of the pivoted member 61 the slot 63 is tangent to the'arcuate path of movement of the pin 28. As a result, reverse actuation of the armature by the member 61, either through inadvertence or through a deliberate attempt, is impossible while the member 61 is in either of its extreme rest positions. Thus a highly effective yet simple locking action is achieved, serving to maintain the armature, and all the parts controlled thereby, in its extreme positions. This makes the device highly resistant to shock and vibration, regardless of how small the parts may be in relation to the load they serve to move.

The actuating articulation between the member 61 and the element to be moved, such as the arm 29, may be of any suitable or desired character. For illustrative purposes the arm 61 has been shown provided with an actuating pin 64 which rides withinthe forked end 65 of an arm 66 secured to the shaft 36 and thus controlling its movements.

It will be understood that many of the details herein described and illustrated may be modified by those skilled in the art without necessarily departing from the spirit and scope of the invention as expressed in the appended claims.

tive only.

1. In a magnetic motorof the character described, a fixed housing including opposed poles, an armature centrally and pivotally mounted between said poles for swinging movements between symmetrical rest positions on opposite sides of the magnetic axis, an electric circuit for energizing said poles to initiate armature movement from one rest position to the other, means for automatically breaking said circuit prior to the midpoint of armature movement, the inertia of said armature carrying it beyond said midpoint, and a bowed constant-force spring interposed between the armature and the housing, the anchorage of said spring to the housingbeing aligned with said magnetic axis.

2. In a magnetic motor, the elements defined in claim 1, there being two of said springs in diametrically opposed.

movement, the inertia of said armature carrying it beyond said midpoint, and a pair of bowed constant-force springs interposed between the armature and the housing, said springs being bowed in opposite directions and having their ends secured to common anchorages on said arma- Except as otherwise stated, therefore, it is intended that these details be interpreted as being illustra- I, ture and housing respectively, the housing anchorage axis.

5. A rotary solenoid mechanical movement comprising a fixed housing including opposed magnetic poles, an armature pivotally mounted for swinging movements between symmetrical rest positions on opposite sides of the magnetic axis, a pivoted member in driven relation to said armature and adaptedto swing between two corresponding rest positions, and means for preventing reverse actuation of said armature by said driven member, comprising a pin carried by said armature, and a slot in said member within which the pin moves when the armature swings, the pivot of saidmember being 'so located that in each rest position of said member the slot is tangent to the arc of pin movement.

6. In a magnetic motor of the character described, a fixed housing including opposed poles, an armature pivotally and centrally mounted between said poles for swinging movements between symmetrical rest positions on opposite sides of the magnetic axis, an electric circuit for I energizing said poles to initiate armature movement from one rest position to the other, means for automatically breaking said circuit prior to the midpoint of armature movement, the inertia of said armature carrying it beyond said midpoint, a pin ecc'entrically projecting from one end of the armature, and a member in driven relation to the armature and pivoted to swing between two symmetrical rest positions, said member having a slot with which said pin engages to swing said member from one rest position to the other as the armature makes a corresponding swing, the pivot of said slotted member being so located with respect to said armature and pin that in each rest position of said member the slot is tangent to the arc of pin movement, whereby reverse actuation of the armature by said member is impossible when the latter is in either of its rest positions.

, 7. In a magnetic motor of the character described, the combination of elements defined in claim 6, in which said siotted member is provided with an actuating part adapted. to move the element to be actuated by said motor. 8.111 a magnetic motor of the character described, a fixed housing including opposed poles, an armature centrally and pivotally mounted between said poles for swinging movements between symmetrical rest positions on opposite sides of the magnetic axis, on electric circuit for energizing said poles to initiate armature movement from one rest position to the other, means for automatically breaking said circuit prior to the midpoint of armature movement, the inertia of said armature carrying it beyond said midpoint, a pin eccentrically projecting from one end of the armature, and an end wall on the housing provided with an arcuate slot through which said pin projects, the ends of said slot serving as abutments to limit the swings of said armature.

Switzerland Apr. 15, 1941

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