Miniaturized precision speed gyroscope

Miniaturized precision speed gyroscope having high stability in time and as the temperature varies and suitable to withstand impacts. Such a gyroscope comprises a motor, the connections of which to the motor windings are provided with connectors, the bushings of which are within the shaft and the pins of which are in the set screws of the shaft. The differential transformer of the gyroscope has only one coil for each of the poles, is provided with a damping device with four crossing plates overlying four holes for adjusting the aperture thereof. The gyroscope contains a silicone liquid, in which three air bells enclosed within three resilient silver caps are immersed.

This invention relates to a miniaturized precision speed gyroscope. 
As well known, a speed gyroscope is an electric machine performing the sole 
function of providing electrical information and which, as all of the 
electric machines, has to bedimensioned in accordance with the power to be 
delivered. 
The power for electrical information, when desiring that the latter be 
represented by a few volts across a resistance of a few thousands of ohms, 
as occurs in the use range of speed gyroscopes, is in order of a few 
milliwatts. Accordingly, it will be readily evident that, when rationally 
implemented, a gyroscope may weigh only a few grams and be of a very small 
size. 
Speed gyroscope, at present known and used, have a weight of about 150 
grams and a volume of about 35 cm.sup.3. This is a substantial 
disadvantage, since the weight and overall size thereof are a serious 
handicap, particularly when such gyroscope are fitted on small planar 
antennas. ;p It is the primary object of the present invention to provide 
a precision speed gyroscope which is as miniaturized as possible and has 
unique characteristics, such as extreme precision, high stability both in 
time and with temperature variation, as well as high capability against 
impacts. 
It is another object of the invention to provide a gyroscope of the above 
outlined character, having simple component parts and which can be readily 
made and assembled. 
These and still other objects are accomplished by a gyroscope comprising a 
container, on the outer surface of which two prismatic millings are 
formed, a bottom connected to said container and carrying a moving element 
by means of a torsion bar fitted with an impact protecting device 
comprising a ball bearing carried on said bar with a clearance or play 
between the inner ring and ball crown, two end of stroke stop pins, which 
can be adjusted from outside and are accomodated within conical seatings 
in said bottom and provided with stop collars, teeth projecting from said 
stop pins in the rotational path of teeth projecting, in turn, from said 
moving element, a differential transformer internally of said bottom and 
having a plurality of poles with only one coil for each of the poles and 
with a rotating core secured to said moving element and comprising 
magnetic cores as circular sectors magnetically independent of one another 
and half the number of the number of poles in the differential 
transformer, a motor, the shaft of which is hollow and is secured to said 
moving element also by hollow set screws, the two connections to the motor 
windings being provided with two connectors, the bushings of which are 
located within the shaft and the pins of which pass through said hollow 
set screws and are connected to a power supply, a damping device 
comprising four fins secured to the moving element and rotating within 
four slots provided with four bimetallic plates crossing one another and 
located two by two in different planes varying the opening of the slot 
bottom as the temperature varies, a liquid for filling up the free space 
in said housing or container, and three air bells enclosed within three 
resilient silver caps immersed in said liquid, the connections between 
different and interlocked parts of the gyroscope being effected by conical 
surfaces with stop collars for ensuring both axially and radially accurate 
and simple positionings.

It should be noted that FIGS. 3, 4 and 5 are shown on a reduced scale 
relative to FIGS. 1 and 2. 
A gyroscope according to the invention comprises a container or housing 22, 
having mounted and connected thereon a conical bottomm 18, the latter 
being provided with a stap collar 15. A differential transformer 24 is 
seated in said conical bottom 18 and has a plurality of poles 32, each of 
which is provided with only one rigid and geometrically perfect coil 26 
and having a rotating core secured to the moving element 30 comprising 
magnetic cores 28 as circular sectors, magnetically independent of one 
another and corresponding in number to half the number of poles in the 
differential transformer. 
The bottom 18 has also secured thereto conical and of stroke stop pins 16, 
each of which is provided with a collar 12 and has projecting teeth 20 
located in the rotational path of teeth 23, in turn projecting from moving 
element 30, the stroke of which is thus defined by adjusting said conical 
stop pins 16 from outside the gyroscope. 
Accomodated within said bottom 18 is a torsion bar 25 fitted wih fastening 
cones 19 and 33 with stop collars 21 and 27 and having a ball bearing 29 
mounted thereon. It should be noted that a clearance or play 31 is 
provided between the ball crown and the inner ring of bearing 29, due to 
which said torsion bar 25 is protected against impacts, but without 
causing any friction during normal operation. Collar 27 of torsion bar 25 
is of conical shape of aid in easily removing said bar from moving element 
30. The moving element 30 carries a motor 42 comprising a shaft 37, a core 
47, a winding 38, a rotor 36, 46, only partially shown in sectional view 
of FIG. 1, and two ball bearings 40 supporting said rotor on shaft 37. 
Shaft 37 of motor 42 is carried and clamped on moving element 30 by two 
screws 39. The connections to the windings of motor 42 are comprised of 
two connectors, the bushings 43 of which are insulated internally of 
hollow shaft 37 and the pins 41 of which are insulated internally of 
hollow set screws 39. The outer ends of pins 41 are connected through 
connections 35 to a supply power outside of the motor. 
Moving element 30 is carried by bottom 18 through torsion bar 25 and by 
support or bearing 53 through a pair 48 rotating within a bore drilled 
within a hard stone 50. 
A conical plug 44 is fast or integral with moving element 30 and has stop 
shoulders 45 and four fins 52 inserted and rotating in slots 61 of support 
or bearng 53, so as to cause a damping action which by means of four 
bimetallic plates 54 is maintained substantially constant as the 
temperature varies. These four bimetallic plates 54 cross in pairs on two 
intersecting planes 62 and 63 formed in said support or bearing 53, being 
secured thereto by screws 56, whereby each can freely move, such 
bimetallic plates performing the function of adjusting the opening of the 
bottom of four slots 61 as the temperature vaires. Threaded holes 51 in 
conical plug 44 allow the moving element to be balanced by balancing 
screws 49. 
The gyroscope also comprises equalizing caps 57, each of which includes 
resilient silver membranes 55 welded to rings 58 and enclosing air. These 
caps perform the function of equalizing any change in the volume of liquid 
34 as the temperature varies, such liquid comprising silicone fluid. 
It should be noted that the electrical connections for the gyroscope exit 
through loops 17 and bushing 11 secured to a cover 13 applied externally 
of bottom 18, terminal 14 being grounded. 
Container or housing 22 has on its outer surface prismatic millings 59 and 
notches 60, intended to accomodate set screws for enabling fastening 
thereof on a supporting structure, with an accurate orientation along 
three axes or directions. This system is simpler and more precise than the 
system at present used, which restrains the gyroscope position by a pin. 
The described gyroscope, has a weight of 40 grams and a volume of 7 
cm.sup.3 and, under severe tests, showed the capability of enabling such 
accurate detection as even a few degrees/sec about the inlet axis, while 
being subjected to disturbance accelerations of thousands of m/sec.sup.2 
about the drive axis. Thus, it can be stated that such a gyroscope will 
neglect large disturbance accelerations and will always supply correct 
information of the speeds applied to the inlet axis. 
The basic feature of the gyroscope, that has been described with reference 
to the appended drawings, is that all of the connections between the 
several interlocked parts are carried out by conical clamping connections 
with a stop collar. This allows obtaining accurate positioning both 
axially and radially. The differential dimensions due to small processing 
tolerances do not affect the locations of the parts comprising the 
gyroscope, but only the cone constraints which without any damage can be 
increased beyond a strictly sufficient minimum rate. It should be noted 
that this connection system by conical surfaces with stop collars allows 
the distribution of inner stresses both axially and radially, enhancing 
the connections in time and with temperature vartiation. Such a simple 
connection system proved to be by far superior to connection systems 
obtained by soft soldering currently used extrusively. 
Since the differential transformer of the gyroscope has only one rigid and 
geometrically perfect coil for each of the poles, the gyroscope is further 
characterized by having a nearly perfect response linearity to the various 
speeds and a very small "zero" voltage. 
As internally of its shaft the motor is provided with two connectors, the 
gyroscope is further characterized in that the assembling of said motor 
within the moving element is substantially facilitated and both the two 
fragile lead wires, that in other gyroscopes exit fixed centrally of the 
motor shaft, and the weldings of said wires are eliminated, such weldings 
being capable of contaminating the ball bearings. 
It should be noted that preloading of the motor ball bearings is 
exclusively determined by the size of the flywheel which by a suitable 
equipment can be selected to the correct size. This eliminates preloading 
adjustment which at present is provided by turning nuts on the shaft in 
order to position the inner rings of the ball bearings that are then 
retained from inwardly moving by the crowns of the balls to the detriment 
of the latter. Moreover, as the plane of a threaded nut is never at right 
angles to the axis, clamping is always offset. In the described gyroscope, 
it is also important to use four shock absorbers (bimetallic plates 54 
crossing and cooperating with slots 61 and fins 52) acting in two 
different planes with openings varying as the temperature varies, allowing 
the damping factor to be held at a nearly constant rate, which is an 
improvement over prior art gyroscopes having only two shock absorbers with 
the bimetallic plates located on the same plane. 
Finally, it should be noted that, as the gyroscope is very small and highly 
compact, a few drops of silicone fluid will suffice to fill the empty 
spaces thereof, so that the volumetric change thereof is small as the 
temperature varies. Such a volume change is readily compensated by the 
three air bells enclosed within three resilient silver caps replacing the 
cumbersome and expensive bellows currently used.