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Патент USA US2124078

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July 19, 1938.
R, E‘ PALME'R E1- AL
2,124,078
CONTROLLABLE PITCH PROPELLER '
Filed April 14. 1936
5 Sheets-Sheet 1
IN VEN TOR)‘.
PICHARD E. PALMER and
BYCHARLEs 5.J.M\=NEIL JR.
'-
ATTO"
s.
July 19, 1938.
2,124,078
R. E. PALMER ET AL
CONTROLLABLE PITCH PROPELLER
Filed April 14, 1936 '
5 Sheets-Sheet 2
INVENTORS
QICHAQD E. PALMER
CHARLES $.J-MMNEKLJR.
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ATTORN
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S.
July 19, 1938.
2,124,078
R. E. PALMER ET AL
CONTROLLABLE PITCH PROPELLER
Filed April 14, 1936
5 Sheets-Sheet I5
’:'_~Z6_____________,
INVENTOR5.
QICHAIED EPALMER.
BY
CHARLES S.J.Mx-NEIL JR.
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July‘l9, 1938.
R. E. PALMER ET‘ AL
2,124,078
CONTROLLABLE PI TCH PROPELLER
Filed April 14. 1936
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INVENTORS.
QIcHAQD E‘ PALMER
CHARLES s‘mmmem J2.
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July 19, 1938.
2,124,678
R.’ E. PALMER ET AL
CONTROLLABLE PITCH PROPELLER
5 Sheets~Sheet 5
Filed April 14, 1936 '
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Patented July 19, 1938
2,124,078
UNITED STATES PATENT OFFICE
2,124,078
CONTROLLABLE PITCH PROPELLER
Richard E. Palmer and Charles S. J. MacNeil, Jr.,
Kenmore, N. Y., assignors, by mesne assign
ments, to Curtiss-Wright Corporation, a cor
poration of New York
Application April 14, 1936, Serial No. 74,276
4 Claims. (Cl. 170-163)
This invention relates to controllable pitch
aeronautical propellers.
Objects of the invention are to provide a pro
peller hub organization having an improved
5 planetary speed reducer between a relatively high
speed electric motor carried by the hub, and the
propeller blades; to provide an improved bearing
organization for supporting the blade in the hub
each bearing of the stack assumes a proportional
against centrifugal and centripetal forces; to
provide means for permitting movement of the
share of the centrifugal load. This frictional
engagement prevents all of the centrifugal load 10
blades between de?ned pitch limits, said means
comprising switches to break the electric motor
circuit responsive in their action to propeller
blade movement; to provide a composite struc
tural organization in which the several mecha
nisms are compactly disposed to facilitate main
tenance and to render fabricating and assembly
processes easy, and to provide essential com
, ponents in a propeller of the character mentioned
which correlates to produce an eflicient mecha
nism.
In the drawings:
Fig. 1 is a side elevation of a propeller embody
ing the invention, partly in section;
Fig. 2 is an enlarged axial section through the
' speed reducer;
30
its socket l2, while allowing free turning of. the
blade. When the propeller is in operation, cen
trifugal blade forces tend to force the blade out
of the socket, whereby the inner and outer races
of the bearings I‘! are jammed against the blade
and socket, producing a substantial irictional en
gagement between races and surfaces by which
Fig. 3 is a section on the line 3-3 of Fig. 2;
Fig. 4 is an enlarged section through the speed
reducer showing the gear relationships;
Fig. 5 is an enlarged section on the line 5-5
of Fig. 4;
Fig. 6 is a section through the propeller hub
showing details of the limit switch;
Fig. '7 is a section on the line '|—l of Fig. 6;
Fig. 8 is a section on the line 8-—8 of Fig. 7;
Fig. 9 is a section on the line 9-9 of Fig. 8; and
Fig. 10 is a section on the line Ill-40 of Fig. '7.
Referring ?rst to Fig. 1, there is shown a pro
peller hub it having a plurality of. blade sockets
l2 each having a cylindrical bore l3 within which
40
a ball bearing i5 is inserted, the outer race of the
latter resting
a socket shoulder l4. This bear
ini~ is, as ‘s apparent in the drawings, arranged
foi
nning radial loads due to propeller blade
El
thrust, and axial, inwardly directed loads. A
propeller blade 46 is encircled by the bearing l5,
and a plurality of ball bearings I‘! are stacked
on the bearing 55 to assume radial and outwardly
directed, or centrifugal loads. It will be noted
that the outer races of the bearing l5 and the
innermost bearing ll are separated by a clearance
IE, to prevent abutment of the races when the
blade holding nut l 9 is screwed Within the socket
to bear upon the outer race of the top bearing I1.
55 By screwing in this nut, the several ball bearings
are pre-loaded by which the outer race of the
bottom bearing I1 is pressed toward the outer
race of the bearing l5, thus positively establishing
the positions of the bearings to prevent either
60 inward or outward movement of the blade IS in
being assumed by the outermost bearing I‘! and
the nut l9.
By this bearing arrangement, effective piloting
of the blade in its socket accrues, the blade being
positively held in perfect alinement. A maxi 15
mum of resistance to bending stress in the blade
is afforded, by having the relatively large diam
eter ball bearings and by the relatively great
distance between the outermost and innermost
ball bearings.
20
A locking lug 20 is arranged for holding the
nut [9 in place, Vernier slots 2| and 22 being
formed in’ the nut I9 and blade socket I2, re
spectively, to receive the lug.
The inner end of the blade I6 is provided with
a combined abutment and bevel gear sector 23,
which may be integral with the blade, or may be
rigidly attached thereto by screw threads and a
pin 23', as shown. The bevel gear sector 23 is
drivably engaged with a bevel gear 24 coaxial
with the propeller hub, this gear 24 being the 30
driven element of a speed reducer 25 coaxial
with, and mounted ahead of the hub H in a
housing 26. An electric motor 21 is mounted on
the housing 26, ahead thereof and coaxial there
35
with, and serves to drive the speed reducer.
The speed reducer is shown in detail in Figs.
2 to 5 and comprises what might be termed a
differential planetary gear train. The motor
shaft 28 carries a driving pinion 29, which is
meshed with a plurality of planet pinions 30 borne 40
in a planet carrier 3| carried on bearings 32
in the housing 26. Encircling the carrier 3| is an
internal gear 33, fixed in the housing 26. Tan
dem planet pinions 34 are integral with the
pinions 30, and therefore revolve at the same
speed as the pinions 30. A driven internal gear
35 encircles and engages the pinions 34, and is
driven thereby. By referring to Fig. 5, it will be
seen that the pitch circle diameters of the gears
-50
33 and 35 are only very slightly different, the
difference (in radius) being designated at 36. In
the present embodiment, wherein a speed reduc
tion of 1 to 25,000, or thereabouts, is desired, the
diameter differential, represented by 36, is very 55
small, and gear teeth of appropriate pitch are
chosen to eifect proper meshing between pinions
30 and gear 33, on the one hand, and pinions 34
and gear 35 on the other hand. It will be ap
parent that a very high speed reduction ?ows 60
2
2,124,073
from this arrangement; since the gear 33 is sta
tionary, gear 35 will creep relative thereto at a
rate determined by the proportion of the dimen
sion 36 to the pitch radius of the gear 33 through
the functioning of the planet pinions, which in
turn are driven at reduced speed by the pinion 29.
The driven internal gear 35 is attached to the
blade driving bevel gear 24.
In the type of propeller described in Patent No.
10 1,951,320, issued to W. J. Blanchard, a somewhat
similar blade pitch changing organization is de
scribed, using, however, a “heliocentric” speed
reducer. The planetary speed reducer here de
scribed has been found to be much more e?icient,
15 since the gears transmit their driving effort by
gear tooth contact, rather than by sliding pin
contact which obtains in the heliocentric reducer.
Previously, to provide gear trains to eifect speed
ratio changes on the order of 25,000, a multiplicity
20 of epicyclic or ordinary gears, or a series of worm
reductions have been deemed necessary which are
obviated by this mechanism.
The electric motor used in the propeller herein
coincidental registry of these terminals occurs
when the power unit is assembled to the hub, the
terminals being ready for contact in accordance
with the positions of the cams 40 and 4|.
While we have described our invention in detail
in its present preferred embodiment, it will be
obvious to those skilled in the art, after under
standing our invention, that various changes and
modi?cations may be made therein without de- '
parting from the spirit or scope thereof. We aim
in the appended claims to cover all such modi?
cations and changes.
What is claimed is:
-
1. In a controllable pitch propeller comprising
a hub, blades rotatably mounted in the hub for 15
pitch change, an electrically energized power unit
consisting of a motor and a speed reducer, said
unit being detachably mounted in coaxial rela
tion with the propeller hub, conductors for the
motor carried within the power unit and having 20
terminals substantially at the mounting plane of
the power unit, cooperating terminals carried by
the propeller hub adapted to match with the re
shown is reversible, and is preferably reversible ‘ spective power unit terminals when the power unit
25 by having “forward" and “reverse" ?eld windings is in assembled relation on the hub, and blade 25
which are connected to a selector switch in the pitch limiting switch means operated by the power
aircraft through suitable slip rings and brushes
between the propeller hub and power plant. To
prevent an operator from effecting propeller blade
30 pitch changes beyond the proper operating range
of pitch, means are provided to open the motor
circuit when the blade has been moved by the
motor to the limit position. This organization is
shown in Figs. 6 to 9 and comprises cam rings 40
and 4| carried ~by the driven shaft portion 42 of
the speed reducer 25. This shaft rotates the
propeller blades for pitch change thereof. The
lobe on the cam ring 4| engages a cam follower 43
comprising a. bellcrank pivoted at 44 to the hous
ing 26, the lower end 45 of the bellcrank being
bifurcated to embrace a switch terminal 41 adapt
ed to make electrical contact with a button ter
minal 49 mounted in the hub I |, the terminals 41
and 49 being guided axially by a sleeve 48. Figs.
45 8 and 9 show the cam 4| operating the cam fol
lower to open the switch after the propeller has
unit for moving said terminals into and out of
contact with each other.
I
2. In a controllable pitch propeller comprising
a hub, blades rotatably mounted in the hub for 30
pitch change, an electrically energized power unit
consisting of a motor and a speed reducer, said
unit being detachably mounted in coaxial relation
with the propeller hub, conductors for the motor
carried within the power unit and having termi 35
nals substantially at the mounting plane of the
power unit, cooperating terminals carried by the
propeller hub adapted to match with the respec
tive power unit terminals when the power unit
is in assembled relation on the hub, and blade 40
pitch limiting switch means operated by the power
unit for moving said terminals into and out of
contact with each other, said limiting means be
ing mounted in and being removable with said
power unit upon detachment thereof from the 45
propeller.
been adjusted to the limiting high pitch position.
3. In a controllable pitch propeller, a hub, a
The cam 40 operates on a cam follower, bellcrank
unitary electric power unit having an attaching
face in fitting engagement with said hub, means
for attaching said unit to said hub, blade pitch 50
control switches electrically connected with said
and switch, similar to those described, to control
This low
pitch switch is always closed except when the cam
opens it in response to movement of the propeller
blades to the low pitch limit. Thus, either one of
the high pitch or low pitch limit switches are
55 always closed, so that, should the high pitch limit
switch have been opened, the low pitch circuit is
in readiness to operate the motor.
50 the low pitch limit of blade position.
The speed reducer 25 and the motor 21 are
unitary with the housing 25, the latter having at
60 tached thereto a ?ange plate 5| by screws 62; the
plate serving as a carrier for the gear 24 and also
serving as a mounting for a de-icing spinner
which may embrace the whole power unit. The
whole unit, with the plate 5|, is attached to the
65 hub II by screws 52 shown in Figs. 7 and 10. The
number 53 inFlg. 6 represents the mounting plane
of the power unit to the hub. A spline connection
54 serves as a separable driving connection be
tween the elements 24 and 42 when the unit is
70 removed, and the electrical terminals 41 and 49
respectively stay with the power unit and hub
' upon power unit removal, the bellcranks 45 like
wise staying with the power unit upon removal of
the latter; It will be noted that the terminals 41
75 and 49 are close to the mounting plane 53, so that
unit and carried thereby, electrical cn bles in said
hub having terminals adjacent to the attaching
face. and elements of said switches carried by and
movable relative to said unit, movable into and 55
out of contact with said terminals during pro
peller operation, said switches and elements being
bodily removable from said propeller hub and sep
arable from said terminals as part of said unit.
4. In a controllable pitch propeller, a hub hav
60
ing a mounting face, electrical cables carried in
said hub having contact terminals at said mount
ing face; an electric motor power unit having a
mounting face for ?tting engagement with said
hub mounting face, switch elements movable with 65
and relative to said unit, connected with said
motor, having contact points contactable with
said terminals upon switch actuation when said
unit is assembled on said hub, said contacts and
elements being so disposed on respective mount 70
ing faces as to be in position for operative con
tact upon assembly of said unit upon said hub.
RICHARD E. PALMER.
CHARLES S. J. MACNEIL, _JR.
76
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