US3110126A - Overcontrol preventer for miniature captive airplanes - Google Patents

Description

Nov. 12, 1963 M. G. KRETZMER, JR 3,110,126

OVERCONTROL PREVENTER FOR MINIATURE CAPTIVE AIRPLANES Filed Sept. 19. 1960 3 Sheets-Sheet l INVENTOR Wfifiebgm/t,

ATTORNEY Nov. 12, 1963 M, G. KRETZMER, JR 3,110,126

OVERCONTROL PREVENTER FOR MINIATURE CAPTIVE AIRPLANES Filed Sept. 19. 1960 3 Sheets-Sheet 2 INVENTOR M ATTORNEY OVERCONTROL PREVENTER FOR MINIATURE CAPTIVE AIRPLANES Filed Sept. 19. 1960 Nov. 12, 1963 M. G. KRETZMER, JR

3 Sheets-Sheet 3 INVENTOR ATTORNEY United States Patent QVERCSNTR: L F 53 IVHMTURE CAPTWE Minor G. Kretzmer, in, Middle liladdam, Conn, as to The A. (3. Gilbert Company, New Haven, (Iona, a

corporation of Mm'yland Filed Sept. 19, 1969, Ser. No. 57,936 ill Claims. (Ql. la- 77) This invention relates to an automatic overcontrol preenter incorporated in mechanism that transmits to the hand of a ground stationed operator the centrifugal pull of an engine propelled toy or model captive airplane as it circles about the operator.

It is known to mount a transmission mechanism for this purpose on the under surface of a Wing of the plane to be operated by a pair of flexible control lines reaching inboard of the arc of plane travel to the operator. Such strands are capable of being seesawed by the hand of the operator in a manner to vary the angle oi incline of an aerodynamic control surface in relation to fixed surfaces on the plane while in flight. Such control surface may be that of an elevator swlngable in relation to a stabilizer to which the elevator is hilged so as to cause the plane to climb or to nose downward at the will of the operator.

it is a general object of these improvements to cause the lirm'ts of the range of movement of an elevator or other plane control surface to become varied automatically in accordance with the speed of gyration of the plane. Changes in plane speec when launching or landing a toy captive airplane vary the intensity of centrifugal pull of the plane in a direction outboard of its arc of travel and consequently vary the force with which the circling plane pulls on the operator held control lines.

A more specific object is so to arrange the speed-deter mined control of the limits of elevator movement that for the avoidance of overcontrol such range becomes automatically more restricted when the airplane is flying at relatively high speed than when dying at relatively low speed, whereby to compensate for the more sensitive response of the plane to change of inclination of its elevator or other control surface at the higher speeds of flight.

Another object is to cause the permissible range of elevator movement to be thus automatically varied in both directions of elevator swinging movement.

Anot er object is to provide means whereby there can be variably set and predetermined the ratio of the range of movement automatically permitted to the elevator to the speed or" the airplane travel.

Another object is to incorporate the improved over-control preventer in a simple unitary mechanism that transmits the pull of the control lines to a direction that accords with the arc of travel of the plane.

Still another object is to construct a unit of transmission mechanism so that it can readily be attached to or removed from the wing or frame work of a toy airplane by simple means such as a couple of small screws. in tms way a given transmission unit is interchangeably applicable to different airplanes.

The foregoing and other objects of the invention will be clear in greater particular from the following description of successful embodiments of the improvements having reference to the accompanying drawings wherein:

FIG. 1 is a perspective view of a self-powered miniature toy or model captive airplane showing the overcontrol preventer of these improvements carried on the undersurface or" a wing of the plane as when banliing in flight.

PEG. 2 is a bottom plan view or" the overcontrol preventer mounted on the Wing of tl1 plane with certain parts positioned in accordance with relatively low speed of plane travel.

FIG. 3 shows certain parts of FIG. 2 shifted automatically in position to accord with relatively higher speed of plane travel.

FIG. 4 shows certain of the parts or" FIG. 3 rocked to differing positions by seesawin manipulation of the control lines for causing the plane to climb or to nose downward.

FlG. 5 is a view taken in section on the plane 5-5 in FIG. 2 looking in the direction of the arrows.

FIG. 6 is a View taken in section on the plane 6--6 in FIG. 2 looking in the direction of the arrows.

7 is a view similar to FIG. 2 showing a modified cons ruction of the overcontrol preventer likewise embodying the present improvements.

FIG. 8 is a View like FIG. 7 showing certain parts shifted to a different relationship automatically caused by increase in speed and centrifugal pull of the plane.

FIG. 9 shows the parts of FIG. 8 rocked as in PEG. 4 to cause the plane to climb or nose downward at the will oi the operator.

FIG. 10 is a view taken in section on the plane ill-19 in FIG. 7 looking in the direction of the arrows.

ll is a view taken in section on the plane ill-ll in FIG. 7 looking in the direction of the arrows.

Flt}. l2 is a view on an enlarged scale taken in section on the plane 12-12 in PlG. 7 looking in the direction of the arrows.

Eli i3 is a fragmentary view taken in section on the plane 13-33 in FIG. 12 looking in the direction of the arrows.

PEG. 1 shows a miniature toy or model captive airplane having a fuselage '7, a propeller 1% powered by a minature internal combustion engine 9 and equipped with landing wheels 8, as it might appear to an operator stationed on the ground when the plane is banking in flight. The operator is assumed to be holding the twin control lin s and 12in a manner to seesaw them or to pull on either line more forcefully than on the other. A transmission mechanism designated 13 is fastened as a unit to the undersurface of a wing 14 of the airplane and includes a rocker id to which lines ill and 12 are attached on opposits sides of its fulcrum or pivotal bearing 24. Lines ill and 32 are free to slide through guide loops 21 fixed on the win-' surface.

The function of the transmission mechanism '13 is to convert an operator imposed differential of length between control lines 11 and $12 to an elevator member 15 hinged at the edge or" the fixed stabilizer surface 16 by flexible ta es 2 3. The elevator has an aerodynamic control surface whose angle of inclination to the stabilizer surface 16 is determined by a push-pull connecting rod 17 attached to the same rocker 18 as are the control lines 11 and '12.

Connecting rod 17 connects pivotally to the elevator 15 by means of the usual born or coupling bracket 19.

In FIGS. 2 to 5, inclusive, it is shown that the rocker 18 is iulcrumed or pivotally mounted on the aforesaid shiftable bearing 24 which in turn is .carried on a bearing base 23 at slides freely on a guide bracket 25 that is fixed to the surface of wing 14 by wood screws 2/ Slide 23 contains an elongate slot 22 to accommodate its automatic shifting movement relative to guide bracket 25 as hereinafter explained.

The range of swinging movement permitted to rocker is about its bearing 24 is limited in each direction of swing by stop devices in part stationed on the guide bracket 25 in the form of stop pin 27 which is encountered by cooperative stop devices in the form of the convexly curved edge 28 of a stop spur 29 and in the form of conversely curved edge 36 of another stop spur 31. The before mentioned slot 22 in bearing base 23 straddles stop pin 27 which by encountering opposite ends of such slot can establish positive limits to the extent of sliding that can be performed by bearing base 23 relatively to guide bracket '25. Both of the stop spurs 2-9 and 31 are adjustably mounted on rocker 18 by means of fastening screws 32 in a considerable choice of positions permitted by slots 34 and 35 in the respective spurs. Upon being loosened these screws permit the angular relation of either stop spur and the rocker 18 to be varied to suit the behavior characteristic of the toy captive airplane that is to be controlled. it is optional to make stop pin 27 as a screw stud like stop stud 56 in FIGS. to 13 whereby it shall be readily removable to permit unrestricted swinging of rocker 18 for full control of elevator 15.

As an example or" means to cause the limits of movement of the rocker 18 to become automatically varied in accordance with difiering speeds of travel of a given plane, the bearing base 23 is constantly biased by a spring 33 in a direction toward the fuselage of the plane or in an outboard directio-n relative to the arc of travel of the plane. Hence the pull on control lines 11 and 12 is always in opposition to the tension of spring 33 and this pull increases with increase of centrifugal force exerted by the plane when flying at relatively. high speeds of plane travel and becomes less with decreased speed of the plane travel.

In FIGS. 7 to 13, inclusive, a simplified construction is shown wherein the shiftable bearing base 23 is eliminated and the stop spurs 4t! and 41 are formed as an integral part of the modified rocker 42 instead of being adjustable relatively thereto.

The pivotal bearing :for rocker 42 is a simple stud 43 having a thrust head 44 large enough to overlap the edges of an elongate slot 45 in the modified guide bracket 45. Bracket 46 is fixed securely to the surface of the plane wing 14 by the screws 47 in the manner of bracket in FIGS. 1 to 6. At an ofiset shoulder portion 48 of bracketv 46 there is fixedly anchored the free ends 49 of a grasshopper wire spring 59 Whose half loop in the central portion cradles a grooved wheel 52 on fixed stud 43. Thus a constant bias is exerted on the bearing stud 43 to move toward the fuselage 7 of the plane relatively to the guide bracket 46 or in an outward direction in relation to the arc of travel of the plane.

Comparable to the stop pin '27 in FIG. 2, a stop stud 56 is mounted on bracket in the path of swinging movement of the convex edges of the stop spur formationsdl) and 41 on rocker 42. The overall diameter of grooved wheel 52 is sufficiently larger than the width of slot 45 to prevent wobbling of stud 43 in such slot and the axial space between the stud head 44 and wheel 52 accommodates free relative sliding movement as well as free rotary movement between mounting bracket 46 and the rocker 42.

. It will have become apparent from the foregoing description that the amount of play between the convex stop edges of spurs 29 and 31 in respect to the stop pin 27 as well as the amount of play between the stop edges of spurs 40 and 41 with respect to the stop studs 56 automatically becomes less in FIGS. 3 and 8 than it is in FIGS. 2 and 7 owing to the fact that the airplane and the guide brackets 25 or 46 fixed thereto pull outward away 'from the operator and relatively to the pivotal bearings 24 or 43 which are prevented from correspondingly moving outward by the hold of the operator on control lines El and 12. Thus in either of FIGS. 2 and 3 or FIGS. 7 and 8 the rocker element 18 or 42 is free to be varied in angular disposition by seesawing the control lines 11 and 12 in the usual way to position the elevator 15 at selective angles of inclination for causing the plane to climb or to nose downward.

The abruptness of curvature of the stop edges of the spurs will aifect the change in limits of rocker movement that will automatically result from given changes in speed of plane travel. If it is desired to remove all restriction of rocker movement, stud will merely be unscrewed from bracket 46 and removed.

Without the automatic variation in the position of the rocker bearing 24 or 43 that is provided by these improvements there is a troublesome tendency for the operator to swing the rocker such as 13 or 42 a greater degree than is needed properly to control the course or" the plane at its differing speeds of travel, as when launching or landing the plane. This diii'iculty becomes automatically eliminated by this invention because the stopsurfaces 28 and 30 or 49 and d1 slant in such direction with respect to a straight line intersecting the stop abutment 27 or 56 and the fulcrum bearing 24 or 43 that when the plane is traveling at relatively low speed and the pull of centrifugal force exerted by the plane on the control lines 1-1 and -12. consequently is lessened, the distance between :fulcrum hearing 2 or 43 and the stop abutment 27 or 56 becomes shortened by spring 33 or St and a lessened degree of swing is permitted the rocker element 13 or 42 whereby to prevent overcontrol in the diflerential manipulation of the control lines by the operator when the plane is traveling at relatively low speeds. The novel principles involved in the present improvements as defined the appended claims may be embodied in various departures from the shapes and arrangements of parts herein disclosed all of which variations are intended to be covered by the wording of the claims.

What is claimed is:

1. An automatic overcontrol preventer for operating a variably inclinable aerodynamic control surface in a miniature captive airplane, comprising in combination with framework of the plane and a swingable member hinged thereon carrying said control surface, a rod connected to said member to swing the same, a rocker element operatively linked to said rod at a fixed point on said element in a manner to reciprocate said member and having attached control lines for manual operation extending away from the airplane in a direction inboard of the arc of plane travel, a bodily shiftable fulcrum bearing on which said element is pivoted at a constant distance from said fixed point of rod linkage thereto in a manner to permit rocking of said element about said bearing, direction determining means on said framework operative to constrain the bodily shifting of said bearing to directions crosswise of said arc of travel of the captive airplane, resilient means constantly biasing said bearing relatively to said framework in outboard direction relative to said arc of plane travel in opposition to the pull of the operator on said control lines, and stop means in part on said framework and in part carried by said rocker element cooperatively disposed to meet in a manner to limit the extent of rocking "movement of said element 2. An automatic overcontrol preventer as defined in claim 1, in which the said stop means include a stop.

abutment stationed on the said framework of the airplane, and a stop surface carried by the said rocker element shaped and disposed to engage with said stop abutment in a manner to limit the said rocking movement of 7 said element.

3. An automatic overcontrol preventer as defined in claim 2, in which the said stop surface is carried on a spur-like plate, together with means to fasten said plate in variously adjusted positions on the said rocker element. 7

4. An automatic overcontrol preventer as defined in claim 2, in which the said stop surface is curved conmovement of said element in both rotary directions thereof. 6. An automatic overcontrol preventer as defined in claim 5, in which the said stop surfaces are carried respectively on separate plates, together with means to fasten said plates independently of each other in variously adjusted positions on the said rocker element.

7. An automatic overcontrol preventer as defined in claim 1, in which the said resilient means is a cantilever spring engaged with the said fulcrum bearing in a manner to cause relative movement therebetween when the speed of plane travel decreases.

8. An automatic overcontrol preventer as defined in claim 7, in which the said cantilever spring comprises a continuous looping of spring Wire having a central bowed formation cradling the said fulcrum bearing and free ends anchored on the said guide bracket.

9. An automatic overcontrol preventer as defined in claim 2, in which the said stop surface slants with respect to a straight line intersecting the said stop abutment and the said fulcrum bearing in such direction that automatic shortening of the distance between said bearing and said abutment reduces the degree of rocking movement permitted the said rocker element at relatively low speeds or" the plane, whereby to prevent overcontrol of the captive airplane at said low speeds.

10. An automatic overcontrol preventer as defined in claim 5, in which the said stop surfaces are located on respectively opposite sides of the said abutment and slant with respect to a straight line intersecting the said abutment and the said fulcrum bearing in such directions that automatic shortening of the distance between said bearing and said abutment reduces the degree of rocking movement permitted the said rocker element in respectively opposite rocking directions, whereby to prevent overcontrol of the captive airplane at relatively low speeds of plane travel.

References Cited in the file of this patent UNITED STATES PATENTS 2,490,313 Meister Dec. 6, 1949 2,543,965 Hamilton Mar. 6, 1951 2,570,316 Burks Oct. 9, 1951 2,584,588 Hyatt Feb. 5, 1952

Claims (1)

1. AN AUTOMATIC OVERCONTROL PREVENTER FOR OPERATING A VARIABLE INCLINABLE AERODYNAMIC CONTROL SURFACE IN A MINIATURE CAPTIVE AIRPLANE, COMPRISING IN COMBINATION WITH FRAMEWORK OF THE PLANE AND A SWINGABLE MEMBER HINGED THEREON CARRYING SAID CONTROL SURFACE, A ROD CONNECTED TO SAID MEMBER TO SWING THE SAME, A ROCKER ELEMENT OPERATIVELY LINKED TO SAID ROD AT A FIXED POINT ON SAID ELEMENT IN A MANNER TO RECIPROCATE SAID MEMBER AND HAVING ATTACHED CONTROL LINES FOR MANUAL OPERATION EXTENDING AWAY FROM THE AIRPLANE IN A DIRECTION INBOARD OF THE ARC OF PLANE TRAVEL, A BODILY SHIFTABLE FULCRUM BEARING ON WHICH SAID ELEMENT IS PIVOTED AT A CONSTANT DISTANCE FROM SAID FIXED POINT OF ROD LINKAGE THERETO IN A MANNER TO PERMIT ROCKING OF SAID ELEMENT ABOUT SAID BEARING, DIRECTION DETERMINING MEANS ON SAID FRAMEWORK OPERATIVE TO CONSTRAIN THE BODILY SHIFTING OF SAID BEARING TO DIRECTIONS CROSSWISE OF SAID ARC OF TRAVEL OF THE CAPTIVE AIRPLANE, RESILIENT MEANS CONSTANTLY BIASING SAID BEARING RELATIVELY TO SAID FRAMEWORK IN OUTBOARD DIRECTION RELATIVE TO SAID ARC OF PLANE TRAVEL IN OPPOSITION TO THE PULL OF THE OPERATOR ON SAID CONTROL LINES, AND STOP MEANS IN PART ON SAID FRAMEWORK AND IN PART CARRIED BY SAID ROCKER ELEMENT COOPERATIVELY DISPOSED TO MEET IN A MANNER TO LIMIT THE EXTENT OF ROCKING MOVEMENT OF SAID ELEMENT.

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