US 3488611 A
Description (OCR text may contain errors)
J. AQHARPER MULTIPLE: SWITCH CONTROL jan, 6, 1970 Filed Nov. 22, .1966
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MULTIPLE SWITCH CONTROL 2 SheetsPShwt z fram/M United States Patent O U.S. Cl. 335-170 4 Claims ABSTRACT OF THE DISCLOSURE A plunger for operating a plurality of switches to control the feathering of propellers is movable either manually or by a remotely controlled solenoid from a normal position to a first of two opposite limit positions. The plunger is automatically yieldingly retained at this limit position both by a mechanical detent and by a holding coil, the holding coil being energized independently of the solenoid in response to arrival of the plunger at the limit position. The plunger may be returned to its normal position by overriding manual force in opposition to the retaining forces of both the detent and the holding coil.
This invention relates to a control device of the type in which an actuating plunger is movable longitudinally to cause a plurality of radially projecting longitudinal cam elements on the plunger to operate a corresponding plurality of associated switches in a predetermined manner.
Although the invention is widely applicable for its basic purpose, it has special utility in a particular system for controlling the feathering of the blades of airplane propellers. This particular application of the invention is described herein by way of example and disclosure.
The plunger of a feathering control of the type to which the invention pertains has a normal position for normal flight. The plunger is movable in one longitudinal direction from its normal position to a first operating position to feather the propellers and is movable in the opposite direction from the normal position to a second operating position to unfeather the propellers.
One of the needs for improvement to which the invention is directed is to simplify the fixed structure in which the plunger is mounted thereby to increase the eiciency and reliability of the device and at the same time to reduce the cost by simplifying the fabrication and assembly of the device. In this regard, one feature of the invention is the concept of a housing structure made in sections for simple end-to-end assembly. A second feature is the concept of incorporating in the fixed structure of the device a unitary annular frame having radial plates on which an annular array of radially positioned switches may be mounted for operation by the cam elements of the actuating plunger.
Another feature of the invention is the provision of means to bias the actuating plunger to its normal mutual position from both of its two opposite operating positions. For this purpose, as will be explained, a pair of floating washers on the actuating plunger are urged apart by spring means and cooperate with a pair of shoulders on the plunger and a pair of shoulders of the surrounding fixed structure.
A feathering control of the particular type to which the invention pertains incorporates a solenoid to carry out the feathering of the propeller blades by remote control. When the actuating plunger is shifted from its normal position to its feathering position, however, it is mandatory that it remain in that position until overriding manual force is applied directly to the plunger to retract the plunger. A further feature of the preferred embodiment 3,488,611 Patented Jan. 6, 1970 of the invention relates to the provision of means to retain the plunger in its feathering position in the required releasable manner.
In the presently preferred embodiment of the invention, the solenoid which is employed to shift the actuating plunger to its feathering position is provided with a holding circuit controlled by a switch that is responsive to the shifting of the plunger to its feathering position. For this purpose the solenoid has a main driving coil and a secondary holding coil, the main driving coil being under remote control and the holding coil being energized by the switch that responds to the movement of the plunger. Thus energizing the solenoid by remote control to shift the actuating plunger to its feathering position results in electrically retaining the actuating plunger in its feathering position until overriding manual force is applied to retract the plunger. As a safety feature, the manually releasable means for retaining the plunger in its feathering position further includes mechanical detent means. For this purpose suitable spring actuated detent elements are adapted to releasably seat in a circumferential groove of the actuating plunger. In the event that the electrical holding circuit fails, the mechanical detent is capable of retaining the plunger in its feathering position until overriding manual force is applied. The strength of the electromagnetic holding force created by the holding coil combined with the resistance to release by the mechanical detent is only moderate so that overriding manual force may be easily applied to retract the plunger.
The features and advantages of the invention will be readily understood from the following detailed description and the accompanying drawings.
In the drawings, which are to be regarded as merely illustrative:
FIG. l is a rear end elevation of the presently preferred embodiment of the invention;
FIG. 2 is a longitudinal sectional view of the device with the operating plunger in its normal intermediate position;
FIG. 3 is a transverse section along the line 3 3 of FIG. 2 showing the mechanical detent means;
FIG. 4 is a fragmentary longitudinal section on an enlarged scale along the line 4-4 of FIG. 3;
FIG. 5 is an end elevation of the actuating plunger showing the radially projecting longitudinal cam elements of the plunger;
FIG. 6 is a diagrammatic View showing the cam elements in profile in relation to the normal position of the actuating plunger;
FIG. 7 is a perspective view of an annular frame that is incorporated in the fixed structure of the device for the purpose of supporting an annular array of switches that are operated by the cam elements;
FIG. 8 is an enlarged fragment of FIG. 2 showing the means for biasing the actuating plunger to its normal position from its two opposite operating positions; and
FIG. 9 is a wiring diagram showing the holding circuit of the solenoid.
GENERAL ARRANGEMENT The principal parts of the selected embodiment of the invention shown in the drawings include: an operating plunger, generally designated 20, having a knob 22 for manual actuation; a housing, generally designated 23, providing xed structure in which the operating plunger reciprocates; an annular array of radially positioned switches 24 in the fixed structure having operating buttons 25; a corresponding annular array of radially movable elements 26 in corresponding radial apertures 28 Of a concentric tube 30 that surrounds the actuating plunger; and a corresponding annular array of radially projecting cam elements 32 of the plunger shaped to displace the ICC 3 radially movable elements 26 for actuation of the switches.
The parts are shown in FIG. 2 with the actuating plunger at its normal intermediate position. With the parts in the position shown in FIG. 2, the plunger may be pushed inwardly of the housing 22 to shift the plunger to a rst operating position which is the position for feathering the propellers. On the other hand, the plunger may be retracted outward beyond its normal position to a second operating position for unfeathering the propellers.
Within the scope of the invention various components may be added to the basic combination. Thus this particular embodiment includes a solenoid in the form of a tapered cylindrical armature 34 fixedly mounted on the plunger 20 and a surrounding coil 35 in the fixed structure of the housing. It is contemplated that the solenoid will be operated by remote control to feather the propellers and, as heretofore stated, it is further contemplated that the operating plunger will remain in its feathering position until overriding manual force is applied to retract the plunger.
FIG. 9 shows diagrammatically how the coil 35 of the armature may include a main actuating coil 35a and a weaker auxiliary holding coil 35b. The main coil 35a is controlled by two wires 36 from a remote control switch (not shown) and the holding coil 35b is controlled by a switch 24a which is operated by the plunger and which is included in the annular array of switches 24. As indicated in FIG. 9, rightward movement of the plunger 20 to feather the propellers results in closing of the switch 24a to energize the holding coil 35 to mechanically retain the plunger at the feathering position and leftward movement of the plunger to unfeather the propellers opens the switch.
In the event of failure of the holding circuit, a mechanical detent serves the same purpose as the holding coil. As best shown in FIGS. 3 and 4, the mechanical detent comprises a circumferential groove 40 in the actuating plunger and a pair of diametrically opposite detent elements 42 that are adapted for releasably engaging the groove. Each detent element 42 is slidingly mounted in corresponding radial bores 44 and is urged radially inward by a corresponding spring 45 that is in compression between the detent element and an outer set screw 46.
A further addition to the basic combination in this particular embodiment of the invention is means to bias the operating plunger 20 towards its normal position from the two opposite operating positions. As shown in FIG. 2 and more clearly shown in FIG. 8, the biasing means includes the following: a first floating washer 48 and a second floating washer 50 on the operating plunger 20; a coil spring 52 acting in compression between the two floating washers; a first annular shoulder 54 and a second annular shoulder 55 on the operating plunger 20, the two shoulders facing towards each other and straddling the two floating washers, the first shoulder 54 being formed by a narrow flange of the plunger and the second shoulder 55 being formed by the armature; and a first fixed annular shoulder 56 and a second fixed annular shoulder 58 provided by the fixed structure surrounding the operating plunger. At the normal operating positions of these parts shown in FIGS. 2 and 8, the compressed coil spring 52 is at maximum extension to spread the two floating washers apart, the two floating washers at this time abutting both the corresponding shoulders of the actuating plunger and the corresponding shoulders of the surrounding fixed structure. In the construction shown, an additional washer 60 is interposed between the second floating washer 50 and the second annular shoulder 55 of the plunger but this additional washer is in effect a part of the annular shoulder 55.
If the actuating plunger 20 is shifted to the right as viewed in FIGS. 2 and 8, the first floating washer 48 is shifted to the right by the annular shoulder 54 of the plunger but the second floating washer 50 is held stationary by the second fixed shoulder 58 with the consequence that the coil spring 52 is compressed to resist the movement. On the other hand if the actuating plunger is moved to the left as viewed in FIGS. l and 8, the second annular shoulder 55 of the actuating plunger which is formed by the solenoid armature 34 shifts the second floating washer 50 leftward to compress the coil spring 52, the first floating washer 48 being held stationary by the first fixed shoulder 56.
STRUCTURAL DETAILS In this particular embodiment of the invention the housing or fixed structure 23 comprises a plurality of circular sections joined together in end-to-end relation. The first section 23a of the housing 23 encloses the solenoid coil 35 and the armature 34 is made in two parts which are releasably interconnected by spring pressed radial pins 64. The first section 23a has an integral threaded nipple extension 65 which is provided with a pair of nuts 66 to permit the device to be mounted on an instrument panel in a well known manner. The first section 23a further provides a relatively thick radial wall 68 to accommodate the radial bores 44 of the detent means.
The second section 23h of the housing comprises a thick ring of insulating material which accommodates a first set of radial terminals 72 for the various switch circuits. These terminals are connected to the switches 24 by internal wiring (not shown).
The third section 23e of the housing accommodates the annular array of radially positioned switches 24 and for this purpose incorporates a rigid unified annular frame of the construction shown in FIG. 7. The annular frame comprises two opposite end plates 75 and circumferentially spaced radial plates 76 that interconnect the end plates. Since in this particular embodiment of the invention there are eleven radial switches 24, the annular frame has eleven radial plates 76 each of which has two screw holes 78 to receive two screws 80 (FIG. 1) for mounting a corresponding switch 24. The two end plates 75 of the annular frame are in the form of rings with radially inward extending tongues 82 for contact with the previously mentioned inner tube 30 to center or align the annular frame with the inner tube. The two end plates 75 of the annular frame also have suitable bores 84 to receive screws (not shown) for anchorage to the adjoining second and fourth sections of the housing. The third section 23C further includes an outer sleeve 85 of insulating material that telescopes over portions of the two adjoining sections of the housing.
The fourth section 23d is an end disk made of insulating material to accommodate a circular array of terminals 86 as shown in FIGS. l and 2. The terminals 86 of the fourth section, like the terminals 72 of the second section, are employed for external wiring of the various switch circuits. There are eleven switches 24 but one switch is internally wired for the previously mentioned holding circuit and does not require an external terminal 86. It is for this reason that FIG. 1 shows ten terminals 86 instead of eleven.
In this particular embodiment of the invention the knob 22 of the actuating plunger 20 is illuminated and for this purpose the knob has a translucent end wall 88 and the knob houses a suitable lamp bulb 90. In the construction shown, the knob 22 is further providedwith a circular skirt 92 which telescopes over the end of the previously mentioned nipple extension 65. The ferrule terminal of the lamp bulb 90 is grounded to the actuating plungr 20 and the axial end contact of the lamp abuts the head 94 of a conductor rod 95 that is mounted inside the actuating plunger 2l). A suitable coil spring 96 acting against the head 94 continuously urges the conductor rod 95 against the axial end contact of the lamp to maintain the lamp circuit. T he conductor rod 95 is centered at one end by a surrounding insulating sleeve 98 and is centered at the .other end by a surrounding insulating ring 100.
The second end of the conductor rod 95 abuts a floating spring seat 102 in a tubular terminal 104 which is supported and insulated by the material of the fourth section 23d. In the construction shown, the tubular terminal 104 is formed with an outer annular shoulder 105 in abutment against an inner annular shoulder 106 of the fourth section 23d and the tubular terminal is pulled tight against the shoulder 106 by a nut 108. The oating spring seat 102 is urged continuously against the end of the conductor rod 95 by a suitable coil spring 110.
FIG. 2 shows the position of the conductor rod 95 and the iloating spring seat 102 at the normal or intermediate position of the actuating plunger 20. If the actuating plunger is shifted longitudinally to the right to its feathering position, the conductor rod 95 displaces the floating spring seat 102 to the right against the resistance of the coil spring 110. On the other hand, if the actuating plunger 22 is shifted longitudinally to the left to its unfeathering position, the coil spring 110 forces the floating spring seat 102 to follow the retracting conductor rod.
OPERATION With the parts in the positions shown in FIG. 2, the' actuating plunger 22 may be shifted rightward to its feathering position by energization of the solenoid coil 35 or in an emergency the actuating plunger may be moved manually. When the actuating plunger is shifted to its feathering position, the detent groove 40 of the actu-ating plunger moves into register with the detent elements 42 with consequent yielding immobilization of the actuating plunger by the detent elements. At the same time the rightward movement of the actuating plunger to the feathering position closes the previously mentioned holding switch 24a to energize the holding coil 35b of the solenoid. When desired, the airplane propellers are unfeathered by manually retracting the actuating plunger 20 through the intermediate position to the alternate leftward unfeathering position in opposition to the retaining force of both of the detent elements and of the holding coil.
In this particular embodiment of the invention the eleven cam elements 32 of the actuating plunger 20 have the prole configurations shown diagrammatically in FIG. 6 to move the corresponding ball elements 26 radially for cooperation with the corresponding operating buttons 25 of the radially positioned switches 24. In F IG. 6` the central vertical line 112 represents the intermediate position of the actuating plunger 20. The cam elements 32 are moved to the right relative to the line 112 in FIG. 6 when the actuating plunger 20 is =moved to its feathering position and the cam elements are moved to the left relative to the line when the actuating plunger is moved to its unfeathering position. The cam elements in FIG. 6 are designated 32a-32k and the corresponding ball elements are designated 36u-36k.
It is apparent in FIG. 6 that at the normal intermediate position of the actuating plunger 20, the balls 26a-26C, 26j and 26k are at their radially inward switch-releasing positions at which the corresponding switches 24 are not operated. The remaining balls 26d, 26e and 26g-26j are in their radially outward positions for operating the corresponding switches.
When the actuating plunger 20 is shifted to the right from its normal intermediate to its feathering position, it is apparent that balls 26a-26e, 26j and 26k are shifted to their radially outward switch operating positions; the balls 26d, 26g, 26h and 26j move inward to their switch releasing positions; Iand the balls 26 and 26 remain in their outward switch operating positions.
On the other hand, when the actuating plunger 20 is shifted leftward from the intermediate position to the unfeathering position, the balls 26a-26C and 26k remain in their retracted switch-releasing positions; the balls 26d, 26g, 26h and 26j remain in their outward switch operating positions; the balls 26e and 261 shift from their radially outward positions to theirradially inward switch releasing positions; and the ball 26f shifts from its inward position to its outer switch-operating position.
My description in specific detail of the selected embodiment of the invention will suggest various changes, substitutions and other departures from my disclosure within the spirit and scope of the appended claims.
1. In a device of the character described wherein an actuating member is manually longitudinally movable to advance from a normal position to an operating position in a surrounding fixed structure and is provided with a pl-urality of radially projecting longitudinal cam elements to actuate a surrounding array of corresponding switches,
the combination of:
spring means acting between the actuating member and the -fixed structure to bias said actuating member to said normal position; a remotely controlled solenoid to shift the actuating ,member to said operating position; and
means carried by the fixed structure and acting between the fixed structure and the actuating member to retain the actuating member at said operating position in response to movement of the actuating member to the operating position, said retaining means being non-positive and yieldable in response to overriding manual retraction force applied to the actuating member, said retaining means including a holding coil to retain the actuating member electromagnetcally and including a switch to close a holding circuit through the holding coil in response to movement of the actuating member to said operating position,
whereby when the actuating member is manually advanced from its normal position to its operating position it is automatically retained until manual retraction force is applied to the actuating member in opposition to the retaining means to retract the actuating member with the assistance of the spring means.
2. A combination as set forth in claim 1 in which said retaining means further includes a mechanical detent to yieldingly engage the actuating member to hold the actuating member at said operating position in the event of failure of the holding circuit.
3. In a device of the character described wherein an operating member is manually longitudinally movable in a surrounding xed structure from a normal position in opposite directions to two alternate operating positions selectively, said operating member being provided with a plurality of radially projecting longitudinal cam elements to operate corresponding switches,
the improvement comprising:
the provision of means acting between the operating member and the fixed structure to bias the operating member in opposite directions from said two operating positions to said normal position; and
the provision of means to retain said operating member at one of said two operating positions in response to movement of the operating member to said one operating position, said retaining means being yieldable to release the operating member in `response to overriding force applied to the actuating member,
said retaining means including a holding coil to retain the operating member electromagnetically and a switch to close a holding circuit through the holding coil in response to movement of the operating member to said operating position.
4. An improvement as set forth in claim 3 in which said retaining means further includes a mechanical detent to releasably engage the actuating member to hold the actuating member at said operating position in the event of failure of the holding circuit.
References Cited UNITED STATES PATENTS 5 5/1926 Hart 335-170 12/ 1957 Kramer.
8/ 1963 Kitscha 335-254 1/ 1965 Daugherty 335-74 4/1965 Lory 335-164 10 6/1965 Horberg. 12/1965 Horst 335-167 8 Mazuranic-Iankovc 335-73 Framhein 20C-153.12 Herberg. Glaze 200-1 OBrien et a1. 335-253 BERNARD A. GILHEANY, Primary Examiner D. M. MORGAN, Assistant Examiner U.S. C1. X.R.