close

Вход

Забыли?

вход по аккаунту

?

код для вставки
sept-17, 1946. '
2,407,796
H. E. PAGE
TRIPOD JACK
Filed Aug. 17, 1945
` 2 Sheets-Sheet l
O
76
.Js
_.1.J
ü
,Q
_b
„
,_
„_
„__
w
n
a
ìwî2lœ5îi:l 3
M_#
w
_w
«m
_a_ nœ
_ l\
_ _ WW/.v
_.lVm
777m
n,
_w
ÍÉ._8 m.ladìfMw îEzn xM|ì_ß»EL._+ANN:œ\wJ\s\a\
_ l_wp
./|V Èë
2„R
@T
,m
_ ._ _
j
MÈ
_._
„y
ß2»
r„L
ëw
“
M
_ .9
l__
__
w
__
_ n
_ __
_
Sept. 17, 1946.
H. E. PAGE
TRIPOD JACK
Filed Aug. 17, 1943
~2,407,796
_
2 Sheets-Sheet 2
Patented Sept. 17, f1946
2,407,796
UNITED STATES PATENT OFFICE
2,407,796
TRIPOD JACK _
Herbert E. Page, Pasadena, Calif. Y
Application August 17, 1943, Serial No. 498,930
13 Claims.
(Cl. 60-52)
1
2
This invention has to do with jacks and, more
which latter provides a fulcrum for the pumping
particularly, it relates to hydraulically actuated
lever 2li. A tubular guide member 25 has its
tripod jacks such as are used for raising loads
lower end threaded into the socket I'l and pre
to substantial heights. Although such jacks have
sents a cylinder 26. Threaded filling plug 21 is
many uses, oney of the chief uses is as an air 5 provided for reservoir I2.
plane jack.
A body 3D presents a cylinder bore 32 and a
While tripod jacks are known in the art, here
relatively larger cylinder bore 33. Within the top
tofore they have had certain inherent shortcom
end of bore 33 there is a threaded sleeve 35 within
ings such as lack of proper rigidity, limitations of
which is slidably >mounted a piston 3l. A` stop
ring 38 is threaded onto the top end of piston
height,` dangerous side sway characteristics, slow
ness of operation, and lack of adequate safety
3l for engagement with the top end of sleeve 35
features.
to prevent further inward movement of piston
It is one of the objects of my'invention to pro
31. The inner end of the piston 31 is recipro
vide a hydraulically actuated tripod jack in which
cably mounted in cylinder 26, which cylinder
the tripods are telescopic and are automatically
communicates with bore 33, an extension screw
extended in consonance with elevation Yof the
39 being threaded into an internally threaded
load, each of the tripods being comprised of a
longitudinal bore 31a in piston 31. rI‘he tubular
piston member and a cylinder member.
member 25 sli'dably ñts in bore 33 of the body, a
Another object is to provide a jack capable of
guide ring 40 being threadedly mounted in the
effecting quick contact with the load to be lifted 20 bore. A stop ring 4l is threaded onto the` top
by a minimum of effort, this feature being by
end of tube 25 and is adapted to be engaged by
way of an improvement upon and a novel adap»
the top end of ring lill when the body 30 reaches
tation of the invention shown in my prior Patent
the upper limit of its movement relative to» the
No; 2,154,956.
tube, as will be hereinafter described. Ring 4|
Another object is to provide a jack utilizing a
has a plurality of fluid-passing ports denoted by
plurality of liftingV pistons which function to de~
the dotted lines Ma in Fig. 1.
crease the pumping effort required to lift a given
A piston 45 reciprocates at one end in cylinder
load and which provides desirable safety features
32 and at the other end in cylinder 1. The upper
against accidental lowering of the load.
end of cylinder 32 communicates with the bore
Another object of my invention is to provide a
5l of a valve housing 59 through port 52. The
hydraulic jack in which hydraulic locks are pro
lower or inlet end of the bore 5| communicates
vided in the tripods to prevent side sway.
with a fluid reservoir 55 in the body by means of
Another feature of my invention resides in its
tube 56 carrying a screen 5l at its lower end.
double acting pressure generating piston.
Another port 58 in the body provides communi
In the accompanying drawings I show and in
cation between valve housing bore 5l and cylin
the following description I describe a presently
der 33.
preferred adaptation of the Ainvention from which
A poppet 5B, having oppositely disposed stems
it will be obvious to those skilled in the art that
my invention possesses still further important
6l», 62, seats by gravity towards the reservoir in
advantages and may be carried out in other spe
ciñe physical forms, all within the broader scope
of the ‘invention as` deñned by the appended
claims.
In the drawings:
b-ore 5I and a ball valve 65 seats towards the
A coil spring B3, seating
40 reservoir in bore 5l.
against _a plug 5d threadedly mounted in bore 5l,
bears against and normally retains ball 65 against
its seat. This spring is of a strength to maintain
ball 35 seated during initial upward movement of
Fig. 1 is a vertical medial section taken on line 45 the body to establish contact with the load to be
I-l of Fig. 2;
Fig. 2 is a top plan View;
Fig. 3 is an enlarged fragmentary sectional view
Showing one ofthe valve elements; and
Fig. 4 is an 4enlarged fragmentary sectional
View showing another of the valve elements.
The numeral 5 designates a base presenting a
cylinder bore l, fluid passageways 8, 9, 9a, l0 and
H, a ñuid reservoir l2, ñuid chambers i4 and I~5-,
lifted, but is yieldable to pressure generated by
the pressure stroke of piston 45 when further
upward movement of the body is resisted by the
load being lifted, thus permitting ñuid. to flow
into cylinder 33 and provide lifting pressure
therein.
The valve housing 50 is held in the-:body bore
'l5 by a snap ring 'l5 and packing rings 1l are
interposed between the housing and the side wall
a threaded socket I1 and a bifurcated boss I8 55. Qf the bore.
2,407,796
3
4
Three bifurcated bosses 88 are provided on the
base 5 and between the bifurcations of each of
the bosses the lower end of a tube 82 is pivoted
by means of pin 83. The interior of each tube 82
provides a piston chamber 85 within which a
piston 86 reciprocates. A rod 81 connects each
of the pistons 86 to an arm 88 formed integral
with the upper end of the body, the upper end
of the rod being pivotally connected to the arm
seated until a substantial resistance, such as is
offered by contact with the load to be lifted, is
encountered. During this initial movement of
the body, ñuid is drawn from reservoir 55 past
poppet | I8 and through port |85 into cylnder 33,
any unsafe back pressure on poppet ||8 being
relieved by the auxiliary, oppositely seating pop
pet ||1. When the load is contacted, its resist
ance to further movement of the body 38 causes
by pin 89. Thus the tubes 82, pistons 86 and 10 valve 65 to be unseated against its spring by the
pressure generated on the upstroke of piston 45
rods 81 provide tripods for the body. A plug 88
and the liuid is therefore forced into cylinder 33
threaded into the top end of each tube l82 pro
through port 5B to lift the body relative to the
vides a bearing for reciprocation of the rod 81.
. base. During this operation, each upward `stroke
The lower end of each cylinder chamber 85
communicates with base chamber I5 through a 15 of piston 45 in cylinder 1 draws fluid from res
ervoir I 2 through ports 9, 9a, into cylinder 1,
flexible tube 95, the three tubes being connect
and on each downward stroke of piston 45 in said
ed into the port || by means of three connection
cylinder lthe fluid thus previously drawn from the
members 85. Chamber I5 communicates with
reservoir is forced past valve'91 into the lower
the cylinder bore 1 through passageway 8, the
passage of ñuid from chamber yI5 to cylinder 1 20 ends of the respective cylinder chambers 85 to
exert lifting pressure against the respective pis
being prevented by ball check valve 91 seating
tons 86. The extension screw 39 may be man
towards cylinder 1. Chamber I5 also communi
ually rotated, as by inserting a rotating pin in
cates with reservoir I2 through port I8, the lat
hole 39a, to unscrew it from the threaded bore
ter communication being controlled by valve
member 98 threadedly mounted in the base. To 25 31a. Inasmuch as upon each downward move
ment of pistons 88 in chambers 85 fluid is drawn
enable fluid to be drawn from reservoir l2 into
from the reservoir I2 through tube |88, there is
cylinder 1 upon the upstroke of piston 45, pas
always some fluid in the upper ends of the
sageways 9, 9a are provided in the body in com
chambers 85 and by closing valve I8I this fluid
munication with chamber |4, the return move
may be trapped in the chambers and, together
ment of ñuid to the reservoir being prevented
with the fluid pressure against the bottom of
by a ball valve 9.9 seating towards the reservoir.
The upper end 85a of the chamber 85 in each
tube 82, above the piston 86 therein, communi
cates With the reservoir I2 through a flexible tube
pistons 86, side sway of the jack is prevented.~ '
The operation of piston 45 in the respective cyl
inder-s 32, 1 being alternate, when the body is
being lifted by pressure in cylinders 32 or 33,
ñuid will be drawn into cylinder 1 from reservoir
I2 and when the body is being lifted by operation
of piston 45 in cylinder 1, fluid will be drawn into
cylinders 32 and 33 from reservoir 55.
|88, a three-way valve | 8| being interposed be
tween the ,tubes |88 and |82. The valve |8| is
of conventional construction and a hand wheel
|83 is provided for manually opening and clos
ing thevalve so that it may be closed to trap hy
It is possible to provide a hydraulic lock in cyl
draulic fluid in the chambers 85 above the pis 40
inder 85 even before the load is fully elevated,
tons therein, for the purpose to be hereinafter
and to facilitate this I provide an auxiliary inlet
set forth.
.
passageway |35 from passage 8 to reservoir I2,
Cylinder 33 also communicates with reservoir
passage of fluid from the reservoir to cylinder 1
55 through a portJ |85 and valve member |86,
through this passageway being prevented by
which latter consists of a valve housing |81 held
check valve |36 seating towards cylinder 1,. Thus
in a body bore |88 by a snap ring |89. A poppet
if it be desired to lock pistons 86 against move
I I8 is slidably mounted in the bore of thehous
ment during the lifting operation-as may some
ing |81, seating towards the reservoir and being
times be necessary when a load exposedto heavyv
urged against its seat by spring |||. A safety
valve is incorporated in the poppet and consists 50 wind pressure is being lifted and such lock is
necessary to prevent side sway-valves |8| and
of a plug ||5 having a port v| I6 against whose
98 are closed. Thereafter the pressure stroke of
periphery an auxiliary hollow poppet I |1 is urged
piston 45 in cylinder 32 will lift the load by pro
by a spring IIB, fluid passing through ports ||9
jecting piston 31 from the body 38, as is the case
provided through poppet ||1. Housing |81 has
a tubular extension |28 disposed in the reservoir, 55 when body 38 reaches the upper limit of its
travel, and the pressure stroke of piston 45 in
the lower end of the tube |28 being closed and
cylinder 1 merely returns fluid to reservoir- I2
the side wall being perforated as shown at |2|.
' through passageway |35,
When piston 45 is
Operation of the device is as follows: To in
being operated in cylinder 1 to raise pistons 88,
itially contact the top end of the screw extension
the check valve |36 is held closed by the screw`
39 or sleeve 35 with the work to‘be lifted, lever
plug |31. Also, if it be desired to raise the load
28 is operated to reciprocate piston 45 in ‘cylin
by lifting body 38 or piston 31 alone and without
ders 32 and 1, respectively, the upper end of
providing a hydraulic lock in cylinders 85, this
the piston operating in cylinder 32 and the lower
can be accomplished by unscrewing plug |31 to
end operating in cylinder 1. Upon each down
Y
>
.
ward stroke of piston 45 niiuid is drawn from res 55 permit valve |36 to be raised.
In lifting extremely heavy loads it may some
ervoir 55 past poppet 88 and through port 52
times require too much manual pumping pres
into the upper end of Acylinder 32, and on each
sure to lift body 30 or piston 31 by pressure gen
llPWard stroke of the piston in cylinder 32, prior
erated in cylinder 32, and in such cases it is de
to establishing contact with the Iwork to be lift
ed, the spring-pressedvalve 65 and poppet 88 70 sirable to utilize only the pressure generated in
cylinder 1 to raise the three pistons 86. To ac
trap the fluid in cylinder 32, causing the body to
complish this it is only necessary to screw valve
be lifted into contact with the work by virtue of
|38 inwardly to open valves 88, 65 which renders
the iluid pressure between the top efnd of piston
45 and the adjacent end of cylinder 32. Valve
cylinder 33 ineffective.
spring 63 is made strong enough to 11016, Valve 6_5
To lower the load, valve IUI is opened and the'
5
6
valve screw 98 `is unscrewed to permit the iiuid
Aand each piston chamber above the piston there
Y
trapped below the pistons inthe respective cyl
in, valve means operable to open `and close said
inders «8'5 -to flow back into `the reservoir l2 and
thus relieve the pressure in «those cylinders.
Either simultaneously or subsequently, the valve
line, and hydraulic means for moving the body
relative :to the base,
actuating screw 139 is screwed into ‘the valve
rmovable relative yto the base, cooperating piston
and piston <chamber means provided in the base
and body, a telescopic tripod supporting the body
from the basaeach leg of the tripod comprising
housing '5D Vuntil its "tapered inner end contacts
stem 6l and lifts >poppet El! off its seat, which
`force relieves the pressure in cylinder 32 and
further operation vof the Ascrew L30 causes stem
62, lwhich is normally spaced from ball `|55, to
contact and lift said ball off its seat to relieve
.the pressure Vin cylinder 33. Either one of the
screws 98 or läß may be employed to control the
rate 'of descent by `control-ling the rate of return
¿flow-of the hydraulic iiuid to the reservoir.
-|-I‘he advantages of my ¿ack nwill be readily
understood when it is realized that such devices
are employed to lift loads to substantial heights,
4.
the combination of a base, 'a body
a tubular member providing a cylinder and a
piston member reciprocably mounted therein,
vone oi said members being _pivotally connected
to 'the base and the other being pivotally con
nected (to the zbody, `said body `and base present
ing .respectively 'oppositely opening concentric
cylinder bores, ,a >pumping -piston reciprocably
mounted at one
in 'one of the cylinder bores
and at its other V‘end in the other cylinder bore,
means providing communication between one of
often of the order of eight feet or more, and 20 said cylinder bores and said piston chamber and
when the load surface is exposed to the wind a
means `providing communication between the
considerable side sway would develop but for >my
,other Acylinder bore and the cylinder in each of
novel construction wherein the tripod pistons 86
may be locked against reciprocation in the tubes
82, Moreover, the multiple cylinders in the pis
tonsV materially reduce the manual eiïort re
quired to lift a given load and also distribute the
stresses. The double acting piston 45 also saves
`considerable time. The automatic quick contact
the respective legs, whereby reciprocation of said
pumping >piston valternately generates pressure in
the piston chamber and in the cylinders in the
legs, respectively,
5. In a jack, the combination of a base, a body
movable relative to the base, cooperating piston
and piston chamber means provided by the base
~feature of my device is »also a great advantage as 30 and body, a telescopic tripod supporting the body
a time and labor saver.
I claim:
l.. In a jack, the combination of a base, a
telescopic work-engaging member mounted for
telescopic movement perpendicular to the base,
pressure-actuating ymeans for extending the
work-engaging member, and means for laterally
supporting the work-engaging member compris
-i-ng la plurality oi vtelescopic support members,
each including a cylinder and a'piston, `disposed
symmetrically »around and inclining towards the
work-engaging member, each -oi said telescopic
support members being secured at its opposite
ends to thebase and work-engaging member, and
hydraulic pressure-generating means vcommuni
cating with the cylinders of the support mem
bers.
from the base. >each leg ofthe tripod comprising
a tubular member providing a cylinder .and a
piston member reciprocably mounted therein,
one of said members being pivotally connected
to the base and the other being pivotally con
nected to the body, said body and base present
ing ‘respectively oppositely opening concentric
cylinder bores, a pumping piston reciprocably
mounted at one end in one of the cylinder bores
and at its other end in the other cylinder bore,
means providing communication between one of
movable relative to the base, a telescopic tripod
said cylinder bores and said piston chamber and
means providing communication between the
other cylinder bore and the cylinder in each of
the respective legs, whereby reciprocation of said
pumping pïiston alternately generates pressure in
the piston chamber and in the `cylinders in the
legs, respectively, and means for providing iluid
pressure inthe cylinders of the respective tubu
supporting the body from the base, each leg of ‘
lar members in a manner to oppose movement of
2, In a jack, the combination of a base, a body
the tripod >comprising a tubular member provid
the pistons therein by virtue «of pressure generl
ing a piston chamber therein and a piston mem
ated by the pumping piston,
ber reciprocably mounted in `the chamber, one
'61, In la jack, the combination of a base pre
of said 'members being secured Vto the base and
senting >an upright tubular guide member, a body
the other lmember ‘being secured to >the body, 55 presenting a cylinder `slidably receiving the guide
hydraulic means cooperating with the chamber
member, a work-lifting piston slidably mounted
of `each leg at opposite sides of the piston therein
in the body and reciprocably disposed Vin the
whereby to provide fluid pressure on opposite
tubular guide member, a cylinder bore in the
sides of the piston, and fluid pressure generating
body substantially parallel to the said cylinder, a
means independent of said hydraulic means co
rluid reservoir in the body, a fluid passageway in
operating With the body and vbase ’to raise the
the Abody providing ~communication between the
body relative to the base.
reservoir and cylinder bore, a “check valve
the
3. In a jack, the combination of a base, a body
passageway seating towards the reservoir, a
movable relative to the base, a telescopic tripod
pumping piston reciprocably mounted in the
supporting the body from the base, each leg oi
cylinder bore` a second iiuid passageway in the
the tripod comprising a tubular member pro
body providing communication between the cyl
viding a piston chamber therein and a piston
inder bore and the first-mentioned cylinder, a
mem-ber reciprocably mounted in the chamber,
check valve in the second fluid passagewayl seat
one of said members being secured to the base
ing towards the sai-rl cylinder bore, spring means
and the other member being secured to the body,
normally maintaining the last-named ,check
a fluid reservoir, a iluid pump communicating
valve seated and beingof a strength suiîicient to
with the reservoir and with each piston chamber
oppose pressure generated bv the pumping p-iston
below the piston therein whereby to generate
when the work-lifting piston is out of contact
fluid pressure acting against the piston, a line
with the work to be lifted` but yieldable to said
providing communication between the reservoir
pressure `when the work-lifting piston `is bur
2,407,796
,
7
8
_
dened with the load to be lifted, and a telescopic
tripod pivotally secured at one end to the body
and pivetally secured at its other end to the base.
7. In a jack, the combination of a base pre
senting a fluid reservoir, a first cylinder bore and
a second cylinder bore, a body movable relative
to the base and presenting a chamber concentric
with the ñrst cylinder bore in the base and a
secured at one end to the baseï and at its other
end to the work-lifting element, said work-lift
ing element presenting a pair of parallel cylin
ders, a pumping piston reciprocably mounted in
the ñrst of the cylinders, a work-engaging piston
protractable from and reciprocably mounted in
the second cylinder, a ñuid reservoir, fluid pas
sageways establishing communication between
the reservoir and the ñrst cylinder and between n
ñuid reservoir, a work-lifting piston slidably car
ried by the body and reciprocably disposed in the 10 the iirst and second cylinders, and valve means
in the passageway between the first and second
second cylinder bore in the base, a pumping pis
cylinders maintaining said passageway closed
ton reciprocably mounted at one end in said iirst
when movement of the work-lifting element is
cylinder bore in the base and at its other end in
not opposed by work being lifted, said pumping
said chamber in the body, a tripod having legs
each consisting of a tubular member providing 15 piston being operable' when moved in one direc
tion, in conjunction with the last-named valve
a piston chamber and pivotally secured to the
means and fluid from the reservoir, to extend the
base and a piston reciprocably mounted therein
tripod and move the work-lifting` element into
and secured to the body, intercommunicating
engagement with the work independently -of
passageways in the base providing communica
pressure inthe second cylinder, and hydraulic
tion between the reservoir, the .piston chambers
means operable to exert extending pressure on
in the tripod legs and the first cylinder bore, a
the tripod in response to movement of the pump
check valve in one of Vsaid passageways prevent
ing piston in the other direction.
ing passage of fluid from the piston chambers in
l0. In a jack, theV combination of a base, a
the tripod legs to the ñrst cylinder bore but per
mitting passage of fluid from the ñrst cylinder 25 body, an extensible tripod supporting the body
from the base, each leg of the tripod comprising
bore to the said piston chambers, a second check
a tubular member providing a piston chamber
therein and a piston member reciprocably
mounted in the chamber, one of said members
der bore but preventing passage of iluid from the
first cylinderbore to the reservoir, a manually 30 being secured to the base and the other being
valve in one of the passageways permitting pas
sage of fluid from the reservoir to the ñrst cylin
' ‘operable valve controlling passage‘of fluid from
secured to the body, a piston member carried by
said piston chambers to the reservoir, a ñuid
and projectible from the body, fluid pressure gen
erating means for moving the piston members,
and valve means for selectively communicating
the fluid pressure to the .said tripod piston mem
bers or to the said bodyy pistonmember.
passageway in the Ybody providing communica
tion between the body reservoir and the body
chamber, a check valve in said last-named pas-`
sageway seating towards the body reservoir, a
1l. In a jack, the combinationV of a base, a
second iluid passageway in the body providing
body, an extensible tripod supporting the body
communication between the body chamber and
from the base, each leg of the tripod comprising
the second cylinder bore in the base, a check
valve in the last-named passageway seating to 40 a tubular member providing a piston chamber
therein and a piston member reciprocably
wards the body chamber, a spring urging the
mounted in the chamber, one of said members
.last-named check valve seated, said spring be
being secured to the base and the other being
ing yieldable to pressure generated by the pump..
secured to the body, a piston member carried by
ing piston only when the `work-lifting piston is
burdened by a load being lifted, and manually 45 and projectible from the body, hydraulic means
so operatively associated with the body andthe
actuated means for unseating the last-named
piston member carried thereby as initially to
two check valves.
'
move the body relative to the base until the body
l 8. In a jack, the combination of a base, a
contacts a load to be lifted and subsequently to
work-lifting element movable towards and away
from the base, a longitudinally extensible tripod 50 move said piston member relative to the body to
lift the load, and hydraulic ’means operable to
secured at one end to the base and at its other
extend the tripod.
`
end to the work-lifting element, said work-lift
12. In a jack, the combination of a base, a
ing element presenting a pair of substantially
body, an extensible tripod supporting the body
parallel cylinders, a pumping piston reciproca
bly mounted in the first of the cylinders, a work 55 from the base, each leg of the tripod comprising
a tubular member providing a piston chamber
engaging piston protractable from and recipro
therein and a piston member reciprocably
cably mounted in the second cylinder, a ñuid
~ reservoir, fluid passageways establishing commu
mounted in the chamber, one of said'members
being secured to the base and the other being
inder and between the first and second cylinders, 60 secured to the body, a'piston member carried by
and projectible from the body, hydraulic means
and valve means in the passageway between the
so operatively associated with the body and the
ñrst and second cylinders maintaining said‘pas
nication between the reservoir and the first Cyl
piston member'carried thereby as initially to
move the body relative to the base until the
lifting element is not opposed by work beingV
lifted, said pumping piston being operable when 65 body contacts a load to be lifted and subsequently
to move said piston relative to the body to lift
moved in one direction, in conjunction with the
the load, and hydraulic means operatively asso
last-named valve means and fluid from the res
ciated with the tripod, said last-named means
ervoir, to extend the tripod and move the work
being operable to lock the tripod pistons against
lifting element into engagement with the work
independently of pressure in the second cylinder, 70 movement relative to the tripod piston chambers
whereby to prevent side sway of the body.
and hydraulic means for locking the tripod in
sageway closed when movement of the work
such extended position.
'
9. In a jack, the combination of a base, a
work-lifting element movable towards and away
from the base, a longitudinally extensibley tripod
13. In a jack, the combination of a base, a
telescopic work-engaging member mounted for
telescopic movement perpendicular to the base,
pressure-actuating means for extending the
2,407,796
10
work-engaging member, and means for laterally
supporting the Work-engaging member compris
ing a plurality of telescopic support members,
spective cylinders of the support members to
each including a cylinder and a piston, disposed
provide fluid pressure on opposite sides of the
ends to the base and Work-engaginrmember,
and hydraulic means cooperating with the re
symmetrically around and inclining towards the 5 pistons therein.
Work-engaging member, each of said telescopic
support members being secured at its opposite
HERBERT E. PAGE.
Документ
Категория
Без категории
Просмотров
0
Размер файла
929 Кб
Теги
1/--страниц
Пожаловаться на содержимое документа