Flexible hub magnetic gyro wheel

Flexible-hub magnetic gyro wheel including a ring member comprising ferromagnetic material or the like and including a plurality of alternating magnetic poles circumferentially spaced about the ring member, a flexible hub affixed to the interior of the ring, and structure rigidly attaching the flexible hub to a drive shaft, such as the shaft of a motor or a shaft driven by a motor or other drive structure. The structure for rigidly attaching the flexible hub to a shaft consists of a set collar and a set washer on opposing sides of the center of the hub material whereby the set collar and set washer support the magnetic gyro wheel on an axially rotating shaft. The magnetic gyro wheel is suitable for use in a rate of turn indicator, a gyro, or other like instrument designed to sense and respond to a rate of turn or angular velocity applied to the instrument at a right angle to the spin axis of the magnetic gyro wheel. The magnetic gyro wheel can comprise one or more rings of magnetic material magnetized with alternating poles with the flexible hub attached thereto or can be fabricated from a plurality of magnets held together in such a way as to achieve the characteristics of the magnetized ring or rings described above. As one alternative the magnetic gyro wheel can also be made of a flexible magnetic material magnetized with alternate magnetic domains on one or both sides of the wheel or upon the periphery of the wheel.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates generally to a gyro, and more particularly 
pertains to a magnetic gyro wheel which incorporates a flexible hub, the 
hub replacing the normally used gimbal and gimbal bearings for the purpose 
of allowing the gyro to sense and react to a rate of turn, for use with a 
rate of turn indicator, a navigational instrument, and, more particularly, 
as a nautical navigation aid. 
2. Description of the Prior Art 
Prior art rate of turn indicators have usually consisted of complex gyros 
having numerous mechanical and electromechanical components. The prior art 
gyro wheels were comparatively heavy and were meticulously machined from 
steel or other material such as brass, bronze, lead or other similar 
material, to a high degree of precision. The wheel was usually an integral 
part of a motor and because of the high speed required, the motor was 
usually of the direct current variety with the inherent problems normally 
associated with brushes and commutators such as burned or stuck brushes, 
burned, worn, or shorted commutator segments and electrical sparking and 
arcing. The gyro and motor assembly had to be extremely well balanced 
dynamically. The need for a constant speed led to complicated and delicate 
centrifugal-force operated switches that intermittently interrupted or 
applied electrical power to the motor as needed to maintain a fairly 
constant speed. The switches were a source of trouble, such as sparking 
and burning of the switch contacts, wear of critical moving parts, and, 
along with the brushes, a source of radio interference. It also added to 
the cost of manufacture. Another serious disadvantage was the fact that 
power interruptions caused small but sudden changes in the speed of the 
motor. This speed change caused a noticeable spurious deflection of the 
indicating device used with the gyro. 
Prior art gyro and motor assemblies were mounted in a gimbal ring which 
permitted one degree of freedom as opposed to a fully gimballed gyro such 
as is used in a gyro compass. This "one degree of freedom" is the one 
thing that distinguishes the "rate gyro" from gyros used for other 
purposes. While a single degree of freedom is attained by the use of a 
single gimbal mount for the gyro as used in prior art rate of turn 
indicators thus making an ordinary gyro act as a rate gyro, the gimbal 
mounting limits the gyro's rate sensing ability to one single axis lying 
in a single plane. This limitation may be desirable in some cases such as 
when used for the sensing element of an automatic pilot system for use in 
rough waters or the like, wherein the gyro may be subjected to rotational 
forces around several axes at right angles to the gyro spin axis at any 
given time. The gimbal in this case limits the sensitivity of the gyro to 
the rotational force acting around a desired reference axis such as a 
vertical axis through the vessel or other vehicle upon which it is 
installed. This limitation is neither necessary nor desirable for some 
other uses of the rate gyro, an example being when used to detect a small 
rate of turn of a towboat or a ship operating in calm waters. 
The gimbal and associated bearings introduced another problem of friction. 
Any appreciable amount of friction in the gimbal bearings drastically 
affects the accuracy, sensitivity, and response of the rate of turn 
indicator. This is especially troublesome in rate of turn indicators used 
on towboats or on ships when they are being slowly maneuvered in close 
quarters. Under these conditions a degree of sensitivity, accuracy, and 
response to very small rates of turn is required that is not encountered 
in fast, highly maneuverable vehicles such as aircraft and the like. 
Another problem with gimballed gyros when used as the sensing element of 
rate of turn indicators as used in the towboat industry arose from the 
fact that the instrument is primarily used to help the pilot of the vessel 
to steer a straight course. Used in this way, the gimbals are nearly 
always in the zero-rate position and will gradually wear the gimbal 
bearings in such a way that they will develop some reluctance to move from 
this position. 
This action, however slight, reduces the accuracy of the instrument at or 
near the zero-rate position and reduces its ability to respond to very 
small rates of turn. The accuracy of the instrument in the zero-rate area 
and its ability to respond to extremely low rates of turn are of utmost 
importance as used on towboats. 
Rate of turn information sensed by prior art gyros was usually transmitted 
to the indicating device such as an electrical meter movement through an 
electromechanical device attached to the gimbal or through a gear train 
driven by the gimbal. Both methods introduced an additional amount of 
friction and further reduced the instrument's ability to respond to a 
small rate of turn since all friction must be overpowered before the 
pointer of the indicator can move. 
Prior art rate of turn indicators are normally supplied in a package of two 
or more separate units that are installed by a skilled technician. The 
units are interconnected by electrical cables and are sometimes remote 
from each other. In a typical installation the indicator unit would be in 
the pilot house of a boat. The gyro unit would be located under the pilot 
house, a storage room, or even, in some cases, the engine room. In some 
cases an additional motor-generator unit is used to supply the DC power 
for the gyro unit. This kind of arrangement complicates service problems 
and increases maintenance cost. 
The gimbal in prior art gyros is held in the zero-rate position by a spring 
or springs when no rate of turn is being sensed and is returned to zero 
position by the same method after a turn is completed. Spring action is 
non-linear, and the readout from the gyro unit is inherently non-linear. 
Prior art rate of turn indicators are normally based on high-speed, 
short-lived, aircraft type gyros that for all the reasons heretofore given 
are, in many respects, unsuitable for use on towboats and ships. 
The faults and limitations of prior art rate of turn indicators apply also 
to the use for which they were designed, for aircraft rate gyros. 
The flexible-hub magnetic gyro wheel of the present invention overcomes the 
disadvantages of the prior art gyros by providing a magnetic gyro wheel in 
combination with a flexible hub which is least in components, least costly 
to manufacture, and which is much more accurate in providing gyroscopic 
information. The flexible hub of the present invention produces a freedom 
of action around an infinity of axes at right angles to the gyro spin 
axis, and yet limits the sensitivity to a single plane as does the single 
gimbal, single-degree-of-freedom rate gyro. The flexible hub makes it 
possible to select any desired axis lying in a plane at right angles to 
the spin axis of the gyro simply by positioning the sensing elements (the 
electric pickup coils) at the proper points around the circumference of 
the gyro. A plurality of pairs of sensing elements properly positioned 
would make it possible to electrically select any one of a plurality of 
axes for examination such as yaw, roll, and pitch. Rates of turn around 
any one of these axes could be examined individually of their vectorial 
resultant determined by vectorial addition. 
SUMMARY OF THE INVENTION 
The present invention provides a magnetic gyro wheel in combination with a 
flexible hub for a rate of turn indicator or other like gyroscopic 
instrument. 
According to one embodiment of the present invention, there is provided a 
magnetic gyro wheel including at least one member of ferromagnetic 
material or the like and including a plurality of alternating magnetic 
poles disposed about the circumference of the ring member, a hub of 
flexible material having a rigidness about the axis but being laterally 
flexible and affixed to the interior of the ring member, and a set washer 
and a set collar disposed opposite on either side of the hub material on 
the axis whereby the set washer and set collar axially support the 
magnetic gyro wheel on a rotating shaft and the hub material provides for 
lateral movement but rigid flexibleness thereby providing the alternating 
magnets to induce current in sensors placed adjacent to one side of the 
wheel and diametrically opposed to each other providing for an indication 
of angular velocity around an axis at right angles to the spin axis of the 
gyro wheel. 
The flexible hub material can be disposed either between two identical ring 
members providing for front-to-back balance of the wheel, or in the 
alternative can be disposed in the middle of one ring member. 
A significant aspect and feature of the present invention is a magnetic 
gyro wheel which provides an indication to adjacent sensors such as two 
solenoid coils diametrically opposed to each other that the gyro is or is 
not being subjected to a rotary motion about an axis at right angles to 
the spin axis of the gyro and if a rotary motion exists, provides a 
positive or negative voltage output from the sensors, the polarity of 
which is indicative of the direction, clockwise or counterclockwise, of 
the rotary motion and the magnitude of which is proportional to the rate 
in some angular unit per unit of time of the rotary motion. 
Another significant aspect and feature of the present invention is to 
provide a magnetic gyro wheel in combination with a flexible hub which is 
least mechanically complex in novel significance and which accomplishes an 
end result having never before been accomplished by the prior art, in that 
the magnetic gyro wheel rotates at a constant speed and alternately passes 
magnetic poles before sensors which indicate the magnitude and direction 
of any angular force that may be acting upon the gyro about an axis at 
right angles to the gyro driving shaft. The angular force, if one exists, 
is the vectorial resultant of one or more force vectors which may be 
acting upon the gyro at any one time. 
One of the most important novel aspects and features of the present 
invention is to provide a magnetic gyro wheel in combination with a 
flexible hub which is not a part of a motor, but may be firmly affixed to 
a motor drive shaft or a shaft driven by other external structure and 
requires no mechanical or electromechanical structure for taking 
information from the gyro. This eliminates all frictional effects of the 
gyro itself allowing for very high sensitivity and accuracy without 
resorting to heavy flywheels operating at very high speeds, and by 
providing the gyro to operate in a compartment separate from the drive 
motor, being connected only to the motor drive shaft which minimizes 
temperature effects from the gyro. The heat generated in the motor by 
electrical resistance and by friction in the bearings may be dissipated in 
a compartment separate from the gyro. As a result of the light weight of 
the wheel and the fact that it is not necessary to drive the gyro at very 
high speed, it becomes feasible to drive the gyro with a small AC motor 
which, since the motor is operating under essentially no-load conditions, 
maintains a speed at or near the synchronous speed of the motor 
eliminating the need for complicated speed stabilizing devices, thus 
eliminating the need for additional power supplies such as DC power 
supplies. All of these features in combination make it possible for the 
first time to design a small, compact, highly energy-efficient, 
single-unit rate of turn indicator that is completely self-contained, 
economical to build, install, operate, and maintain, with superior 
accuracy, sensitivity, response to very small rates of turn, and an 
unprecedented ability to return to a true zero reading after a turn is 
completed. 
Having thus described the invention, it is a principal objective hereof to 
provide a magnetic gyro wheel in combination with a flexible hub. 
One objective of the present invention is to provide a magnetic gyro wheel 
including a flexible hub supporting a plurality of alternating magnetic 
poles disposed about the circumference of the hub material. 
Another objective of the present invention is to provide a magnetic gyro 
wheel for use in a rate of turn indicator or other like navigational 
instrument or gyro obviating the need for gimbals and their associated 
bearings, and the need for mechanical or electromechanical structure for 
taking information from the gyro. 
A further objective of the present invention is to provide a magnetic gyro 
wheel in combination with a flexible hub which is economical to 
manufacture and lends itself for easy replacement of existing gyroscopic 
assemblies.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
FIG. 1, which illustrates a plan view of a flexible-hub magnetic gyro wheel 
10, the present invention, shows a ring member 12, an opposing ring member 
14 as illustrated in FIGS. 2 and 3, and a flexible hub 16 disposed 
therebetween as illustrated in FIGS. 2 and 3. The ring member has an outer 
diameter 12.1, an inner diameter 12.2, and a finite width 12.3 as 
illustrated in FIG. 2. Likewise, ring member 14 has identical outer 
diameter 14.1, inner diameter 14.2 and finite width 14.3, as illustrated 
in FIG. 2. The ring member 12 is of ferromagnetic or like material and the 
ring member 14 can be of identical material or other suitable material. 
Ring member 14 can be either a magnetized ring member as is ring member 12 
or non-magnetized material such as steel to provide fore and aft balance 
for the ring member 12, providing that the inner and outer diameters are 
equal. Ring member 12 includes a plurality of alternating magnetic domain 
poles 12a through 12j, by way of example and for purposes of illustration 
only, and is not to be construed as limiting of the present invention, 
magnetized into the ring member 12 as illustrated in dashed lines in FIG. 
1. There can be any number of pairs of magnetic poles on the face of the 
ring magnet 12, or in the alternative, on the periphery of the ring magnet 
12. If ring 14 is magnetized as is the ring magnet 12 the poles of the 
ring magnets 12 and 14 can complement each other. The magnetic domains can 
take the geometrical shape of a trapezoid, circular, or other 
predetermined shape as so desired. A hub of flexible material such as 
fiberglassed mylar, rubber diaphragm material, or other like material, is 
disposed between ring members 12 and 14 having an outer diameter falling 
in a range between the diameters of the ring members and having an inner 
diameter center hole 16.1 which corresponds to the diameter 20.1 of a set 
collar 20. A set washer 18 and the set collar 20 mount on the sides of the 
axis of the flexible hub 16 and axially support the magnetic gyro wheel 10 
on a motor shaft of a rate of turn indicator or other like instrument. The 
hub material 16 is secured to the ring members 12 and 14 with any suitable 
material such as adhesive or the like. 
FIG. 2 illustrates an exploded end view of the components of FIG. 1 where 
all numerals correspond to those elements previously described. 
FIG. 3 illustrates an end view of FIG. 1 where all numerals correspond to 
those elements previously described. 
PREFERRED MODE OF OPERATION 
The magnetic gyro wheel 10 is positioned on the shaft of a rotating motor 
of a rate of turn indicator or other gyro type of instrument and the set 
collar 20 secures the flexible-hub magnetic gyro wheel 10 securely to the 
shaft of a motor not illustrated in the figure. When the motor attains a 
predetermined speed, the magnetic gyro wheel 10 axially rotates with the 
shaft of the motor. During a turn of a vessel or the like, angular 
vectorial forces cause the magnetic gyro wheel 10 to move with respect to 
the axis of rotation on account of the lateral flexibility of the flexible 
hub 16. The flexible hub 16 provides for center flexibility movement 
consequently causing the alternating magnetic poles or domains to vary 
their distance from electrical sensing coils not illustrated in the figure 
and diametrically opposed to the magnetic gyro wheel 10. As a consequence, 
the magnetic poles on one side of the magnetic gyro wheel 10 move closer 
to the electromagnetic sensing coil, while the magnetic poles on the other 
side of the magnetic gyro wheel 10 move away from the electromagnetic 
sensing coil resulting in a stronger current induced in one of the coils 
and a weaker current induced in the other coil. 
DESCRIPTION OF ANOTHER PREFERRED EMBODIMENT 
FIG. 4, which illustrates a plan view of a magnetic gyro wheel 22, another 
embodiment of the present invention, shows a magnetic gyro wheel 22 
including a ring member 24 having an outer circumference of 24.1, an inner 
circumference 24.2, and a finite width of 24.3 as illustrated in FIG. 5. 
The ring member 24 consists of ferromagnetic material or like magnetic 
material, and includes a plurality of alternating magnetic poles 24a 
through 24j, by way of example and for purposes of illustration only and 
not construed as being limiting of the present invention, alternating 
about the circumference of the ring 24 and extending therethrough the 
finite width 24.3. A hub of flexible material 26 having an outer diameter 
of 26.1, inner diameter of 26.2 affixes in the center of the ring member 
24 and being disposed therein as illustrated in FIG. 5. A set washer 28 
and a set collar 30 mount on opposing sides of the hub 26 about the axis 
26a of the hub material 26. 
The mode of operation of the magnetic gyro wheel 22 is identical to that as 
previously described for the magnetic gyro wheel 10, and for sake of 
brevity is not repeated. 
Various modifications can be made to the magnetic gyro wheels of the 
present invention without departing from the apparent scope of the present 
invention.