US2788962A - Inertia staged starter - Google Patents

Description

April 16, 1957 E. A. TERHUNE 2,788,962

INERTIA STAGED STARTER Filed Feb. 3, 1954 I INVENTOR. w EDGAR A. TERHUNE ATTORNEY United States Patent INERTIA STAGED STARTER Edgar A. Terhune, Little Silver, N. 5., assignor to the United States of America as represented by the Scoretary of the Army Application February 3, 1954, Serial No. 408,057

3 Claims. (Cl. 264-4.)

(Granted under Title 35, U. S. Code (1952), see. 266) The invention described herein may be manufactured and used by or for the Government for governmental purposes, without the payment of any royalty thereon.

This invention relates to timed starters, and more particularly to a device for utilizing a counter-inertia force to time the initiation of an actuating mechanism.

For convenience of description the device of the present invention will be described in connection with its use in initiating the starting time of a rocket. It is to be understood, however, that the use of the device herein is not intended to be so limited.

In a conventional rocket which includes a fuel chamber, an oxidizer chamber and an air chamber, means must be provided to initiate the control valve of the air chamber whereby released air pressure is utilized to urge the fuel and the oxidizing agent into a mixing chamber for reaction to serve as the rocket propellant. Heretofore a mechanical triggering device was provided for opening the control valve of the air chamber which included a stop in the form of a projecting ear close to the top of the launching tower which opened the valve of the air chamber thus initiating the propellant reaction. In operation, the rocket is urged upwardly by a separate booster charge attached to the bottom of the rocket. Momentarily thereafter as the rocket rises a very short distance, the control valve of the air chamber is set in operation as indicated above and the rocket is launched into flight by its own propellant.

By the utilization of the device of this invention the time of starting operation at which time the rocket propellant takes over is delayed until the initial booster thrust is expended. When incorporated into a rocket, the present device actuates the regulator valve of the air chamber after the rocket leaves the launching mechanism so that the rocket will have a considerably greater range than was possible with other actuating mechanisms.

It is accordingly the primary object of the present invention to provide a device for predetermining the starting time of the actuating mechanism which can be dynamically associated with the motion of a carrier vehicle.

It is another object of the present invention to provide a starter as set forth in the preceding object which is rugged and durable, compact, and easily constructed.

In accordance with the present invention there is provided a device wherein a counterinertia force is utilized to determine the starting time of an actuating mechanism, such as a motor, comprising a first means responsive to said counterinertia force, restraining means for maintaining said first means in a predetermined initial position, said first means being urged in a first direction upon application of said force thereto, whereby said restraining means is released or upset, tensioning means for normally urging said first means in an opposite direction during the expenditure of said counterinertia force, and a second means operatively associated with said first means whereby the movement of said first means in said opposite direction starts said actuating mechanism.

For a better understanding of the invention together with other and further objects thereof, reference is bad to the following description taken in connection with the accompanying drawing and its scope will be pointed out in the appended claims.

In the drawing, I

Figure l is a side elevation, partially cut away, of one embodiment of the present invention;

Figure 2 is a fragmentary front elevational view in perspective of the device of Figure 1, and

Figure 3 is a cross-sectional view of another embodiment of this invention.

Referring to Figures 1 and 2, there is shown a preferred embodiment of the present invention. A housing 2 which in this example is of relatively flat configuration and comprises four relatively narrow end walls 4, 6, 8 and 12 and two side walls 10 and 14. Affixed to end walls 4 and 6 are eyelet brackets 16 which are provided for attachment of the housing to a part of the internal framework of a rocket adjacent to the air chamber of said rocket. Within the housing 2 is a mass 28 of predetermined weight, such as a block of metal, and having mounted on its surface a bracket 30 having a central bore therein. Secured to the bracket 30 is one end of a coil spring 18. The other end of spring 18 is secured to a threaded bolt 22 extending into the housing through an opening in the wall 4. Lock nuts 24, 26 and washer 20 are provided on the bolt 22 as shown, to enable the adjustment of tension of spring 18.

Provided on end wall 8 is an assembly for restraining the mass comprising spaced brackets 44 and 46, having openings in register and a shaft 48 supported through said openings. A bar 38 with an enlarged center portion having a bore therethrough is rotatably mounted on the shaft 48 intermediate the brackets 44, 46, a cotter key 52 is provided through an opening in the shaft 48 to prevent its slippage. A spring 42 for normally urging rotation of the bar 38 in a clockwise direction has one end attached to the bar 38 and its other end wound about the shaft 48 intermediate the bracket 46 and an enlarged shaft head 50. Provided through the end wall 8 is a substantially rectangular slot 56, having an upper wall 57, said slot being so positioned as to permit one end of bar 38 to extend into the housing when the bar is rotated counterclockwise. The upper wall 57 of slot 56 is so located in the wall 8 as to prevent bar 38 from rotating more than 90 from the end wall 8 of the housing.

To prevent rotation of the bar from undue clockwise rotation, a stop assembly to halt movement of the lower end of the bar 38 is provided on the outer surface of wall 8 below the slot. The assembly comprises a bracket 62 secured to the end wall 8, and a flat plate which is substantially parallel to the end wall 8 and extends upwardly from the bracket, both the bracket and plate being secured to the end wall 8 by screws 64.

Within the housing 2 and spaced from and substantially in the same plane as the spring 18 is an eccentricallyshaped cam 66 which is partly arcuate along a portion of its periphery and has a groove or channel 67 extending along said periphery. The arcuate portion is substantially U-shaped in cross-section along its outer periphery providing a channel thereby. One end of the arcuate portion terminates in a recessed portion 70 as shown.

The cam 66 is rotatably mounted on a shaft 78 which extends through the cam and intermediate the walls 10 and 14. A hearing 80 is provided on the inner surface of wall 14 to carry shaft 78, and a similar bearing (not shown) is provided on the inner surface of wall 10 for the same purpose.

A pair of linking arms 68, one on each side of cam 66, is pivotably mounted at one end to cam 66 by means of greases 3 an assembly comprising a shaft 72, a cotter key 74 and a washer 76. The other ends of arms 68 are similarly pivotably mounted on bracket 30 by means of a shaft assembly comprising a shaft 32, a cotter key 34 and a washer 36. 7

Also within the housing 2 there is a substantially L- shapcd rocker member 82 having a long leg 81 and a short leg 83 and rotatable at its mid-portion'about a shaft 84- held by bearing 86 secured to the inner surface of wall 14, and a similar bearing (not shown) is provided on the inner surface of wall 10 for the same purpose.

At the angle of the rocker member 82 is rotatably mounted a wheel 88 by means of a shaft assembly comprising a shaft 90, a cotter key 92 and a washer 94. Rocker member 82 is so spaced from cam plate 66 that wheel 88 is received within the channel of cam 66 where- .by the arcuate portion of cam 66 can ride freely along the wheel'88.

Associated with one end of leg 81 of rocker member 82 is a restraining assembly comprising a coil spring 96, one end of which issecured within an opening 98 of member 82, the other. end of the spring being secured to a threaded bolt 102 extending into housing 2 through an opening in the wall 6. Lock nuts 104 and 106 and washer 100 are provided to control tensioning of the spring 96. A cable 110 is secured to one end of the short leg 83 of rocker member 82 through an opening 108 in the leg 83, the other end extending through the housing to the regulator valve of. an air chamber within the rocket.

In operation, the device is cocked manually by drawing mass 28 a sufficient distance from its normal at rest positionagainst the tension of spring 18 to permit the bar to assume the position shown in dotted outline in Figure l which is accomplished by rotating the bar 38 in counterclockwise direction against the tensioning action of spring 42. Bar 38 is held in horizontal position and mass 28 is permitted to be urged in its normal direction by spring 18 until the upper surface of mass 28 bears against the bar 38. By this arrangement, mass 28 cannot be urged further in its normal direction being stopped by bar 38 as the bar cannot be rotated further in counterclockwise direction, being stopped by the upper wall 57 of the slot 56. By this same arrangement, bar 38 cannot return to its normal position in a clockwise rotational direction as the tensioning action of spring 18 urges mass 28 to bear against the bar substantially as shown. At this-point, the arcuate portion of cam 66 will be resting on the wheel 88 a short distance from recessed portion 70.

The booster fires the rocket, so that the acceleration of the rocket during the booster thrust produces a counterinertia force in mass 28. Mass 28, being freely suspended, upon being subjected to the counterinertia force, moves in a direction against the tensioning force of the spring 18, and loses contact with the bar 38. When the acceleration of the rocket is sufficient the mass 28 moves against the actionv of spring 18 a sufiicient distance to permit bar 38 to rotate freely in its normal clockwise direction to the position shown in Figure 2. For the purpose of clarity this location of mass 28 will be referred to as position A. Simultaneously with the movement of mass 28 to position A, cam 66 is rotated to a predetermined distance along its arcuate periphery in a counterclockwise direction due to the movement of linking arms 68; As. thebooster charge is expended, the thrusting force in one direction decreases progressively as does the consequent counterinertia force in the opposite direction, and mass 28 moves freely under the tension of spring 18 past the slot 56 to a location referred to as positionB. This position B is the point where there is substantially no further tension exerted upon mass 28 by the spring 18, and therefore the effective limit point of mass 28 in its movement away from position A. Simultaneously, as mass 28 moves from position A to position B the consequent movement of linking arm 68 causes cam 66 now to ride along wheel 88 in a clockwise direction to the point where the end of the arcuate portion rides off the wheel 88 and the wheel is urged into the recess portion 70 by the tension of spring 96 upon the pivotably mounted rocker arm 81 on which the wheel is mounted. Such action causes a pull upon the cable thereby initiating the rocket motor control.

Figure 3 shows another embodiment of the present invention substantially similar in construction and operation to the device shown in Figure 2. However, in lieu of the mechanical cam arrangement there is provided an electrical actuating means. On mass 28 there is provided a strip of insulating material 120, a strip of conducting material 112 such as copper, silver, or the like, and a layer of insulating material 118 between the conducting material 112 and the bracket 30.

Affixed to the inner surface of the wall is by means of screws 1 .32 is an electrical contact 114 wherein the wall 14 serves as a ground connection. Afiixed to a shallow portion of the inner surface of wall 10 by screws 138 is a layer of insulating material. A second contact 116 in register with contact 114 is affixed to the insulation by screws 134 and is connected to a hot lead wire of a spark circuit (not shown) for ignition of the rocket motor.

A block 122 is affrxed to the inner surface of wall 14 by screws 126 and is in abutment with contact 114. Likewise, a block 124 is afiixed to insulating strip 136 by screws 128 and is in abutment with contact 116. Both blocks 122, 12s serve to protect the contacts from undue forces and shock caused by the movement thereagainst by the mass 28 as hereinafter described.

In operation, the device is cocked and mass 28 is moved to position A as described in connection with the device of Figures 1 and 2. As mass 28 moves from position A to B, while the booster charger is expending itself, con ducting material 112 engages contacts 114 and 116, actuating the spark ignition circuit which in turn starts the rocket motor device. Strip 118 serves to prevent stray currents. It is readily seen that by the device of the present invention the commencement of the rocket motor can be delayed to a time quite near the end of the thrust period of the booster charge without the need of any timing device; thus the maximum altitude for the rocket may be obtained when launched from a moving vehicle. t is apparent that the present invention may also be applied in those situations where a counter-inertia force may be utilized to delay the starting of an actuating mechanism.

While there have been described what are at present considered to be the preferred embodiments of this invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the invention, and it is therefore aimed in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of the invention.

What is claimed is:

1. A device wherein a counterinertia force is utilized to determine the starting time of an actuating mechanism comprising a housing, first means within said housing responsive to said counterinertia force, restraining means for maintaining said first means in a predetermined position, said first means being urged in a first direction upon application of said force thereto whereby said restraining means is released, tensioning means operatively associated with said first means for normally urging said first means in a direction opposite to said first direction upon the expenditure of said force, and means operatively associated with said first means comprising a totatable cam supported on a shaft in said housing, a pair of arms that link the cam and the first means whereby movement of said first means is imparted to said cam, a pivotable rocker arm including a freely rotatable wheel at one end thereof which engages said cam, the other end of said rocker arm including a tensioning means afixcd to normally urge said wheel of said rocker arm into engagement with said cam, and means operatively associated with said rocker arm for starting said actuating mechanism, whereby the movement of said first means in said opposite direction starts said actuating mechanism.

2. A device such as defined in claim 1 wherein said restraining means comprises a spring loaded bar affixed to said housing.

3. A device such as defined in claim 1 wherein said tensioning means operatively associated with said first means comprises a spring having one end affixed to said first means and its other end to said housing.

References Cited in the file of this patent UNITED STATES PATENTS 2,424,390 Ferris July 22, 1947 2,585,749 Di Lorenzo et a1. n Feb. 12, 1952 2,637,791 Bleier May 5, 1953 2,698,886 Statham et a1. Jan. 4, 1955 2,710,578 Rabinow June 14, 1955

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