US2990623A

US2990623A - Self-clearing liquid ballistic for gyro assembly

Info

Publication number: US2990623A
Authority: US
Inventors: Jr William R Keyser
Original assignee: Sperry Rand Corp
Current assignee: Sperry Corp
Priority date: 1959-11-27
Filing date: 1959-11-27
Publication date: 1961-07-04
Anticipated expiration: 1978-07-04

Description

y 1961 w. R. KEYSER, JR 2,990,623

SELF-CLEARING LIQUID BALLISTIC FOR GYRO ASSEMBLY Filed Nov. 27, 1959 INVENTOR WILL/AM KEYSER JR.

ATTORNEY 2 United States Patent 2,990,623 SELF-CIJEARING LIQUID BALLISTIC FOR GYRO ASSEMBLY William R. Keyser, Jr., Charlottesville, Va., assignor to Sperry Rand Corporation, Great Neck, N.Y., a corporation of Delaware Filed Nov. 27, 1959, Ser. No. 855,568

' 3 Claims. c1. 33-226) The present invention relates to liquid ballistic elements for gyro assemblies and, more particularly, to a self-clearing ballistic element which inhibits the formation of liquid globule obstructions in the air tube of the ballistic.

As is well understood in the art, a liquid ballistic imparts a meridian seeking property to the directive element of a gyrocompass. Such a ballistic is utilized in the gyrocompass disclosed, for instance, in Patent 2,887,- 784 issued on May 26, 1956, in the name of Leslie F. Carter and assigned to the present assignee. In the illustrative case of the patent, the ballistic comprises first and second liquid containers which are secured to the gyro rotor case at respective ends of the rotor spin axis. The containers are partially filled with a suitable liquid such as kerosene. The bottoms of the containers are connected to each other by a small diameter tube to provide for the flow of liquid between the containers. The tops of the containers are interconnected by a breather or air venting tube. v

Proper operation of the liquid ballistic, in imparting meridian seeking properties to the gyro directive element, depends on the flow of liquid between the two containers of the ballistic. Any obstruction tending to block such flow would seriously impair the meridian seeking action. In particular, it has been found' that under commonly encountered conditions of'vibration, shock, or tilting ,of the liquid ballistic, a marked tendency exists for the formation of a liquid globule within the air tube interconnecting the ballistic containers. The droplet remains in the region where the ends of the air tube flare into the tops of the respectively associated containers. The surface tension of the liquid prevents the droplet from falling out of the air tube and into the container thereby blocking the tube.

It is the principal object of the present invention to provide a self-clearing liquid ballistic for use with gyroscope directive elements whereby the formation of entrapped droplets within the ballistic air tube is inhibited.

Another object is to provide an improved liquid ballistic having air tube terminations arranged to shed liquid globules.

These and other objects of the invention, as will appear from a reading of the following specification, are accomplished in a preferred embodiment by the provision of a liquid ballistic element comprising first and second liquid containers interconnected by air and liquid ducts to provide a sealed system for the exchange of liquid between said containers. The air duct interconnects the tops of the containers; the liquid duct interconnects the bottoms of the containers. The containers are preferably approximately half filled with a suitable liquid such as, for example, kerosene, when the ballistic element is in a neutral position.

Each end of the air duct, where it enters into the top of its respectively associated container, is tapered so as to have a decreasing cross-sectional area. The tips of the tapered duct ends are submerged beneath the level of the liquid within the containers when the ballistic element is in its neutral position. Each tapered air duct end is apertured above the surface of the liquid to prowide for the free passage of air between the two containers.

' containers contact the air duct termination as a result of, v

ice

In operation, should some of the liquid present in the for example, vibration, shock, or excessive tilting of the ballistic element, the liquid droplet so created in the duct termination will move toward the submerged end of the apertured and tapered air duct termination. When the descending droplet comes into contact with the fluid of the container, the droplet merges with said fluid thus completely clearing the duct. In this manner the air duct interconnecting the liquid containers of the ballistic element is maintained. clear of liquid obstruction which otherwise would impair the proper meridian seeking operation of the ballistic.

For a more complete understanding of the present invention, reference should be had to the following specification and to the appended figures, of which:

FIG. 1 is a perspective view of an illustrative liquid ballistic element;

FIG. 2 is a sectional view of a representative prior art liquid ballistic container showing the location of a droplet near the end of the air duct;

FIG. 3 is a sectional view of a liquid ballistic container modified in accordance with the present invention; and

FIG. 4 is a sectional view of the apparatus of FIG. 3 taken along the line 4-4.

In FIG. 1, liquid ballistic element 1 is adapted by flanges 2 for mounting on the directive element of a gyroscope (not shown). Element 1, for the sake ofillustration, is generally similar to the liquid ballistic disclosed in Patent 2,887,784 and illustrated in FIGS. 3 and 7 thereof. Element 1 comprises liquid containers 3 and 5 corresponding to containers 73 of the patent. Each of said containers is approximately half-filled with a suitable liquid 6 such as, for example, kerosene when the element is in the neutral position depicted in FIG. 1. the neutral position, the liquid 6 also completely fills liquid-duct 7 which interconnects the bottoms of containers 3 and 5. Air duet 8 interconnects the tops of containers 3 and 5 to provide for the free passage of air between the containers. Thus, ducts 7 and 8 and containers 3 and 5 together comprise a sealed system partially filled with a fluid 6 wherein provision is made for the free flow of fluid 6 between containers 3 and 5 when the system is tilted from its neutral position relative to horizontal axis 9.

It can be seen that in the event that the liquid ballistic of FIG. 1 is subjected to vibration or shock or is tilted appreciably with respect to axis 9, the fiuid from the containers will come in contact with the ends of the air ducts at the tops of the containers. This is shown more clearly in the view of FIG. 2. As the result of the surface tension of the fluid, droplet 10 will remain within tube 8 and will not fall into container 3. It will be recognized that so long as droplet 10 remains at the location shown, air and liquid flow between containers 3 and 5 is substantially inhibited. The inevitable result is the loss of the meridian seeking properties afforded by the liquid ballistic. Droplet 10 will continue to block the air duct 8 until it is blown out into container 3 by increased air pressure within tube 8 behind droplet 10.

The formation of the droplet shown in FIG. 2 and the resulting undesirable operation of the liquid ballistic is prevented, in accordance with the present invention, by suitable shaping of the ends of the air duct 8 in the region where they enter their respective containers. In the preferred embodiment shown in FIG. 3, each end of air duct 8 has been modified to resemble the tip of a draftsmans pen. The extremity 11 of each air duct termination extends below the level of liquid 6 when the ballistic is in its neutral position relative to horizontal axis 9 of FIG. 1. The slot 12 cut into each termination 11 pro- 'vides for the normal venting of air through duct 8 to the 3 containers of the ballistic. Slot 12 extends sufficiently above the surface of liquid 6 for this purpose; The slotted termination 11 is further illustrated in the sectional view of FIG. 4 taken along the line 4-4 of FIG. 3.

In operation, should a globule of liquid such as droplet 13 form at one of' the duct terminations 11, the surface tension of the liquid will urge the droplet downwardly as indicated by the arrow toward the decreasing crosssectional area portions of the tapered termination. Droplet 13 will continue its movement until it meets 'and merges with the main body of the liquid 6 thereby completely clearing air duct 8. This action is self-maintaining whereby duct 8 is continuously cleared of droplets whenever they are produced.

It should be noted'that althoughthe tapered duct termination resembles the'tip of a draftsmans pen in the preferred embodiment, such a shape is not uniquely necessary. All that is required is that each air duct end be tapered toward a tip to have a reducing cross-sectional area. Additionally, the tip of the tapered duct termination must at least contact the surface of the liquid when the ballistic is in its neutral position and the tapered termination must be apertured above the surface of the liquid for venting purposes.

While the invention has been described in its preferred embodiments, it is understood that the words which have been used are words of description rather than of limitation and that changes within the purview of the appended claims may be made without departing from the true scope and spirit of the invention in its broader aspects.

What is claimed is:

1. A self-clearing liquid ballistic comprising first and second closed containers, said containers being interconnected at one end by a duct permitting the flow of:

liquid between said containers, said containers being interconnected at the opposite end by a venting duct, said containers being partially filled by a liquid, each end of said venting duct being tapered to have a decreasing crosssectional area toward a tip, said tip at eachend of said venting duct penetrating the surface of said liquid, each tapered end being slotted longitudinally to provide forthe venting of air through said venting duct when said tip is submerged below the surface of said liquid.

2. A liquid ballistic for use in a gyrocompass, said ballistic comprising first and second containers, said containers being interconnected at one end by a duct 'permitting the flow of liquid between said containers, said containers being interconnected at the opposite end by a venting duct, said containers being partially filled to the same level by a liquid when said ballistic is in a neutral position, each end of said venting duct being tapered toward a, tip of decreased cross-sectional area, said tip at each end of said venting duct penetrating the surface of said liquid when the ballistic is in said neutral position, each tapered end being apertured above the surface of said liquid.

3. A liquid ballistic for use in a gyrocompass, said ballistic comprising first and second cylindrical containers adapted for mounting at respective ends of the gyro rotor spin axis, the bottoms of said containers being in terconnected by a tube permitting the flow of liquid between said containers, the top ends of said containers being interconnected by a venting tube, said containers being partially filled to the same level by a liquid when said ballistic is in a horizontal position, each end of said venting tube being tapered toward a tip of decreased cross-sectional area, said tip at each end of said venting tube being submerged in said liquid when the ballistic is in said horizontal position, each tapered end being slotted above the surface of said liquid.

References Cited in the file of this patent UNITED STATES PATENTS 363,177 Sloppz May 17, 1887 1, 69,666 Wheeler June 18, 1918 1,777,958 Brown Oct. 7, 1930v 1,970,883 Bryant Aug. 21, 1934 2,739,390 Carter Mar. 27, 1956