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Патент USA US2259815

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Oct. 21, 1941.
Filed May 7, 1958
‘,1aw mm5PR
I. W
Patented Oet. 21, 1941
Louis W. Greve, Cleveland, Ohio, assigns: to The
0leveiand Pneumatic Tool Company, Cleve
land, Ohio, a corporation of Ohio
Application May 7, 1938, Serial No. 206,620
5 Claims.
This invention relates broadly to fluid motors,
but more particularly to the type of ?uid mo
tor used for retracting and lowering the landing
gear of airplanes and the like.
One object of this invention is to produce a
?uid actuated motor including a pair of tele
scoping cylindrical members, with means for
automatically locking the motor against acci
dental expansion in the event of a i'ailure of the
motive ?uid within the motor.
Another object of this invention is the pro
duction of a ?uid actuated motor equipped with
a locking device located within the“ motor and
forming a compact and light assembly which is
strong, durable and e?icient.
In the drawing:
(Cl. 121-40)
20 leading inwardly toward the piston 2! and
surrounded by the side wall III of a cup-shaped
auxiliary piston 3|, which carries a cup-shaped
resilient washer 32 held in position by a nut 88.
Extending radially throush the side wall ll of
the auxiliary piston ll, there are four equally
spaced rectangular ori?ces 34 each having a
brake shoe 3! radially slidable therein. The in
ner wall It of each shoe is laterally concaved
and longitudinally tapered to ?t on the tapered
peripheral wall is of the extension 28, while the
outer end wall 31 of each shoe is laterally con
vexed and longitudinally straight to ?t against
the inner wall of the cylinder IS.
The shoes
15 35 are of an equal length calculated to enable
limited axial movement of the auxiliary piston
Fig. l is a side elevatio _
view partly in sec
II relative to the extension 28. Interposed be
tion of a ?uid motor embodying the invention
tween the extension 28 and the auxiliary piston
and shown in extended position.
‘3|, there is a compression spring 38 constantly
Fig. 2 is a view similar to Fig. 1, showing the 20 urging the piston 3i away from
the extension 28.
motor in a retracted position.
In the modi?cation shown in Fig. 4, the piston
Fig. 3 is a cross sectional view taken in a plane
I25 and its component cup-shaped resilient
indicated by line 3-3 in Fig. 1.
I28 are detachably secured on the inner
Fig. 4 is a fragmental side elevational view of
cylindrical member I23 by a nut I21. In this
a ?uid motor shown partly in section and illus 25
construction the auxiliary piston It! includes a
trating a modi?cation of the invention.
sleeve 89 having its upper end internally thread
Referring to the drawing in which like sym
ed to receive a plug Iii by which the cup-shaped
bols designate corresponding parts throughout
washer I32 is secured to the piston III.
the several views, I5 represents an outer cylinder
The inner wall I 38 of the sleeve is tapered to
having its upper end closed by an integral head 80 fit
on the tapered peripheral wall I28 of the
It formed with a clevis I‘! for connection to the
extension I28, while its outer wall I3‘! is cylin
fuselage of an airplane. The head It is pro
drical to ?t on the inner wall of the outer cyl
vided with a threaded connection or passage it
inder III. To enable expansion or the sleeve,
through which motive ?uid may be admitted
it is provided with a plurality of longitudinal
into the upper end of the cylinder I5.
35 slots II leading upwardly from the lower end
Screwed on the lower end of the cylinder ii.
thereof and each terminated by a hole I! ex
there is a bearing member It also provided with
tending radially through the upper end portion
a passage 20 for admitting motive ?uid into the
of the sleeve which is reduced in cross section
lower end of the cylinder I5, and carrying pack
an inner annular groove 0. Interposed be
ings 2i held in position by an adjustable gland 40 by
tween the auxiliary piston Ill and the extension
nut 22.
Telescopically mounted within the outer cylin
der I8, there is an inner cylindrical member 21
having its lower end portion protruding there
from and terminated by a connection 24 through
which the inner member 23 may be secured to
the landing gear of the airplane. The other end
portion of the inner member 23 carries a piston
25 and a cup-shaped resilient washer 28 secured
in position by a nut 21 and mounted within the
outer cylinder for slidable ?uidtight engagement
I28, there is also a compression spring I38.
In practice. to the connecting passages I8 and
20 are attached motive ?uid conveying conduits
admitting motive ?uid into the cylinder I5.
These conduits are controlled by a suitable valve
whereby motive ?uid is admitted into the cylin
der it through one passage and free to exhaust
through the other. For the purpose of explana
tion, let it be assumed that the motor is in ex
tended position as shown in Fig. l and that
motive ?uid is admitted into the cylinder I!
with the inner wall thereof.
through the passage III while the passage I8 is
Referring now more particularly to the in
open to exhaust. In this instance, the motive
vention, 28 represents an extension of the in
?uid acting on the piston 25 through its com
ner member 23 having a tapered peripheral wall 65 ponent cup-shaped resilient washer 18, will ef
(act the ?uidtight engagement of this washer
with the inner wall of the cylinder IS. The motive iluid acting on the piston will also cause
the upward telescopic movement of the inner
member 23 resulting in the contraction of the 5
resilient washer m to effect its fluid tight en
gagement with the inner wall of the cylinder Ill,
and drive the auxiliary piston iii until the plug
Ill engages the upper end of the extension III.
This downward movement or the auxiliary piston
motor. During this upward movement, the compression spring 3! acting on the auxiliary piston 3| will maintain it away from the extension
a as shown in Fig. 3. in which instance further axial movement of the piston 3| away from 10
Ill and sleeve Ill relative to the extension ill.
will cause the inner wall I36 01 the sleeve to be
moved out of engagement with the tapered pe
ripheral wall I" of the extension I28, thereby
relieving the sleeve from its frictional locking
the extension 28 is prevented bythe engagement
of the brake shoes I! with the peripheral wall
engagement with the inner wall at the cylinder
HI, and enabling the free downward telescopic
20 of the extension 28 and the inner wall of the
movement of the inner cylinder I23.
cylinder II. The tension of the spring I8 is
In the modi?ed construction above referred
calculated to cause only a slight radial thrust of 15 thereto. it will be understood that the radial
the shoes 35 on the inner wall of the cylinder
thrust resulting from the expansion of the sleeve
II, which radial thrust does not materially afll is acting practically on the entire peripheral
feet the free telescopic movement of the inner
inner wall of the cylinder H5, enabling the sleeve
member II.
to be made of metal having a smaller coe?lcicnt
After the‘inner member 28 has been moved go of friction than that of the brake shoes 35, with
upwardly within the cylinder II, its return stroke
out affecting the locking emoiency of the sleeve.
e?ecting the expansion of the motor by any
In practice, this sleeve is preferably made of
forces other than that of the motive ?uid adsofter metal than that of the cylinder Hi, there
mitted into the cylinder lb'through the passage
by preventing any possible scoring or scratching
II, is prevented by the locking mechanism in- 25 of the inner wall of the cylinder.
cluding the shoes 35. For instance when the
Although the foregoing description is neces
inner member 23 is subjected to an axial pull
sarily of a detailed character, in order to com
tending to e?ect the expansion of the motor,
pletely set forth the invention it is to be under
the extension 28 will tend to move away from
stood that the speci?c terminology is not intended
the auxiliary piston 3|, causing a wedging ac- 30 to be restrictive or con?ning and it is to be tur
tion between the taper wall 29 and the shoes
ther understood that various rearrangements of
35 eil'ecting the radial thrust of the shoes against
parts and modi?cations of structural detail may
the inner wall of the cylinder II, which thrust
be resorted to without departing from the scope
is suillcient to prevent the outward slidable moveor spirit of the invention as herein claimed.
merit of the inner member 23. The extent of 35
the radial thrust oi’ the shoes 35 against the
1. In a device of the character described, a
inner wall of the cylinder II is proportional to
pair of telescoping cylindrical members, passages
the extent of the axial pull to which the inner
admitting motive ?uid into the outer member for
member 23 may be subjected, thereby prevente?ecting the telescopic movement of said mem
ing any noticeable expansion of the motor ir- 40 bers, a sleeve between said members capable oi’
respective of the load carried by the inner memexpansion into frictional locking engagement
her a.
with said outer member. and interengaging
When it is desired to eiIect the expansion of
means on said sleeve and inner member auto
the motor. the motive ?uid may be admitted into
matically effecting the expansion of the sleeve
the upper end of the cylinder l5 through the 45 upon initial movement of said inner member in
connection It, while the connection 20 is opened
one direction by pulling forces to which said
to exhaust. In this instance, the motive fluid
inner member may be subjected.
will first act on the cup-shaped resilient washer
2, In a device of the character described, an
32 to effect its ?uid tight engagement with the
outer cylindrical member formed with a sub
inner wall of the Outer cylinder li- The motive so stantially smooth inner wall, an inner cylindrical
?uid acting on the auxiliary piston ll will drive
member slidable within said outer member, pas
and maintain it in the release position relative to
sages adlnjttlng motive ?uid 1111.0 said outer mem.
the shoes 35. In other Words. the 911111181’! pisbar for e?ecting the slidable movement of said
TDD 1| will be moved from the Position Shown ‘in
inner member, a brake carried by the inner mem
Fig- 3 t0 the Position shown in Fig- 1- thel'eby on her including a sleeve capable of expansion into
084151118 the 8119-1 movement of the locking shoes
frictional engagement with the inner Wall of the
35 from an Operative Position 111150 in hmpel‘ative
outer member for preventing said slidable move
position relative to the telescopms cylindrical
merit in one direction, and means included in said
members ‘5 and 13- With the auxiliary Piston
brake automatically e?ectlng the expansion of
II engaging the upper end 01' the extension 25- 50 said sleeve upon movement of said inner mem
the action 01 the mimve mud on the auxiliary
bet in said one direction by forces other than that
piston Ii is transmitted to the inner member 23
o! the motive ?uid admitted into said outer
for effecting its outward movement resulting in
the modi?ed construction shown
in Fm 4, 65 pair
3. of
In telescoping
a device ofcylindrical
the character
. .
a. pull exerted on the inner member ill will.
to th
due to the engagement of the tapered mating suran
8 mo V6
8 Outer membel
faces I28 and I36. cause the expansion of the
e “ting the teleswpmg mwemem °1 said mam’
sleeve 39 and the consequential frictional en“'3' an exp'msible sleeve between said members
gagement or the sleeve's, outer wall "1 with the 70 movable
friction creating
tween forinto
the telescoping
of the inner member in one direction, and a
inner wall of
wedge on said member automatically moving said
lag outward telescopic movement of the inner
the motive ?uid is admitted
sleeve into friction creating position upon initial
member I23. when of
the cylinder HI through
into the upper end
of said inner member in said one di
the connection, I it, it will act on the cup-shaped
rection by forces other than that oi the motive
?uid aforesaid.
4. In a device of the character described, a
cylindrical housing, a member within said hous
ing having one end projecting therefrom, said
housing and member being capable of relative
slidable movement, asleeve carried by said mem
ber capable oi’ expansion into frictional locking
engagement with the inner wall or said housing
for preventing the slidable movement or said
member in one direction, and means operatively
associated with said sleeve automatically eil'ect
ing the expansion thereof upon initial movement
01’ said member in said one direction by pulling
forces to which said member may be subjected.
5. In a device of the character described, a
cylindrical housing, a member within said hous
in: having one end projecting therefrom, said
housing and member being capable ‘of relative
slidable movement, a main and an auxiliary pis
ton on said member the former stationary there
on and the latter capable oi’ limited axial move
ment relative thereto,- passages through said
housing for admitting motive ?uid to one or the
other of said pistons for eiiecting said relative
slidable movement, an expansible sleeve carried
by said auxiliary piston capable oi’ frictional en
gagement with said housing for preventing slid
able movement in one direction of said member
relative to said housing, and a wedge on said
member e?'ecting the operative engagement of
said sleeve upon axial movement of said member
in one direction relative to said auxiliary piston.
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