US1991453A - Fluid distributor for hydraulic jacks - Google Patents

Description

Feb. 19, 1935. J. A. GlovANNoNl 1,991,453

FLUID DISTRIBUTOR FoRHYDRAULIc .maks

4Filed nec. @195s 2 4sheets-sheet 1 Jr I v H' Feb. y19, 193.5. v A G|0vANNoN| 14,991,453

FLUID DISTRIBUTORA FOR HYDRAULIC JACKS Filed Dec. 8, 1933 2 Sheets-Sheet 2 y whereby a double path and concomitant dupli-y cated piping is avoided, which results in `a lesserfrom a reserve 4Patented Feb. 19, 1935l PATENT -oFFlcE FOR' ` GKS y Jean Albert Giovannoni, Lille, France Application December 8, 1933, Serial No. 701553 In Germany .December 27, 1932` 4Claims.

The present jacks or similar Huid-actuated lifting appliances and has more particular reference to the distributors or valve systems used for forcing the fluid ing the reciprocatable jack piston for actuating it and lifting the load or for allowing the fluid to return to said reserve chamber when the'pressure of .the jack must be released.

-The primary object of vide an improved fluid distributor for hydraulic jacks or the like wherein the fluid from the reserve chamber flowing to the jack piston cylinder and the iluid from said cylinder flowingv back 4to said chamber follow the same path from or towards the reserve chamber owing'to a mere flowreversal placed under the operators control,

volume, lesser number of parts and cheaper cost of the apparatus.

A further object of the invention is to provide an improved fluid distributor of the aforesaid type wherein the reversal of the flow of the actu- ,ating uid is performed by extremely simple means with the aid of valves, distributed along l.said path ina sequence of communicating chambers and requiring no springs since their application' upon, or release from, their seats is per'.- formecl automatically by the mere drag of vthe fluid upon them.

- A still further object of the invention is to prol vide'an improved fluid distributor of the aforesaid type wherein no special or extraneous brak-y ing contrivance is necessitated 'for slackening the rate at which the lifting or jacking piston cornes down when the fluid pressure is released, the braking action taking place automatically owing to the novel arrangement and operation of v ery simple throttling means in the fluid path, as soon as., said rate-of descent exceeds apredetermined' value, which obviates any danger of the load sinking too fast. Y

Still a further object of the'invention is to provide an improved iiuid distributor for hydraulic jacks or the like of extremely simple and rugged structure capable of ensuring a perfect operation even in the long run andof being manufactured f or kept up at relatively low cost.

With these and such other objects in view asv will 4incidentally appear hereinafter, the invention comprises the novel arrangement and disposition of parts that will now be described with reference to the accompanying diagrammatic drawings forming a part of the present disclosure invention relates to' hydraulicv chamber to the cylinder containthe invention is to proand illustrating by wayvof example a suitable embodiment of the invention.

In the drawings: Figure 1 is a fragmentary elevational view partly in section of ahydraulic jack fitted with 5 the improved iiuidldistributor according to the invention, this distributor being shown on the right hand yside of 'thefgure Figure 2` is a diagrammatic view illustrating the fluid distributor, lorr'anenlarged scale, assum- 10 ing the uid tonowinto the control pump chamber to prime said pump. "Figure 3 is a view .similar to Figure 2 assuming the fluid to continu [to flow into the control pump cylinder.v l Figure 4 is a view similargto Figure 2, assuming the piston of the control pump being depressed and the fluid therefrom being forcedv into the jack/ cylinder. y

lFigure `5 is another-view similar to Figure 2, 20 assuming the liftingcpiston'vin the jackcylinder coming vdown under'thep'resjsure of the'load' (not shown), the back iiowgofftlie fluid being throttled by a braking valve-incorporated in the rdistributor. z l, Likereference characters designate like parts v I'throughout the 'severa1vviews..

- Reference being first had to Figure 1, A desigcontrol the flow of fluid actuating the jack, This lever A is linked at Btoafpiston vl accommodated in a distributor cylinder 3. Said lever is fulcrumed on an oscillatable link D.

E designates the cylindrical body of the `lack lhollowed to form a fluid chamber 11,. F desig- -nates the l-lifting or jacking piston encircled at vits upper end by packing rings G therefor and carrying a large nut Hj in which is threaded -a set screw I. The lifting platform J on'which the load to be jacked (not shown) maybe lo- 40 'cated' supported by the top end of the-lifting piston F. Adjacent the cylindrical body E of the i. jack is provided a'reserve chamber '7 for a supply of fluid. At the bottom of saidbody E is arranged a leather `cup L of known form held in- .45 variably in position by agrub screw M.

` The fluid distrib tor is shown more clearly and Y on an enlarged scale in Figures 2 to 5. In the illustrated embodiment, the fluid distributor comprises primarily. a pair of co-axial intercommunicating chambers 4, 5 located in vertical alignment with the control piston 1 to wit:

a primary chamber 5 and a secondary chamber 4 connected by aside duct A2 to the pump cylinder 3.' Through the primary chamber 5 55 nates the actuating lever of the pump adapted-to. n l

a tappet rod 16 slidably fltted through the upper wall of the distributor and having a flange-like enlargement 17 for a purpose that will be described hereafter. The primary chamber 5 is connected to the secondary chamber 4 by a free opening through the lower end of the tappet rod 16 can pass, and it is connected to the reserve chamber 7 containing the supply of fluid by a duct 6. Underneath the secondary chamber 4 is provided a third chamber 8 which freely communicates with said chamber 4 and with a further subjacent chamber 9 which for the sake of clearness, may be termed the fourth chamber. 'Ihis chamber 9 is co-axial with the chambers 5, 4, 8 in the embodiment illustrated but this is not essential for a proper operation of the distributor. 'I'he fourth chamber 9 is connected by a duct 10 with the cylinder 11 formed in the jack body E in which the lifting piston F can reciprocate for jacking purposes.

In the chambers 4, 8, 9 are snugly arranged movable valves which, in the embodiment illustrated, are in the shape of ball valves 14, 13, 15 and are adapted to bear against corresponding seats formed by shoulders provided between these respective chambers which are of increasing cross-sectional area in the downward direction. The valves 14, 13, 15 located respectively in these chambers are similarly of progressively larger volume; they require no springs for being applied upon, or released from, their seats because their application onto, or release from, their seats is performed automatically by the ow of fluid in the one or the other direction., as will result from the following description. The seat between the chambers 8 and 9 for the lower valve 15 is ehamfered or otherwise formed to provide throttle passages 18101' a purpose that will appear hereafter.

'I'he operation of the fluid distributor is as follows: n

As soon as the piston .1' is lifted in the controlpump cylinder 3 by means of the actuating lever A, the suction generated in the secondary chamber 4 draws the valve 14 off its seat in'the opening between the chambers 4 and 5 and permits the fluid sucked from the reserve chamber 7 to flow into the cylinder 3 through the duct 2. The control pump is thus primed. 'I'he valve 13 betweenthe chambers 4 and 8 then remains applied upon its seat owing to the presj Sure head from the cylinder 11 in which the lift-` ing piston F exerts its pressure. The fluid is then drawn through 6-5-2 into the control Dump cylinder 3- while the piston 1 is further.

lifted, as shown in Figure 3. When however the piston l is afterwards depressed (see Fig. 4) the fluid is forced through the duct 2 and chamber v4, as a result of which the valve 14 is pushed up. against its seat, which cuts off communication between the chambers 4 and 5 while pushing/the valve 13 off its seat, whereby the fluid flows through the chambers 8 and 9 and along the duct 10 to the jack cylinder 11. and raises the lifting piston E. By further depressing the control piston 1 by means of the actuating lever A, said piston'comes into contact with the tappet rod 16 engaged through the primary chamber 5, so that this rod pushes the valve 14 downwardly off its seat and re-establishes communication between the chambers 4 and 5. When thus pushed down the valve 14 contacts with the valve 13 and can thuspush it off its seat. The fluid can thus flow back from the jack cylinder 11 through the duct 10 and chambers 9, 8, 4, 5

and through the return duct 6 to the reserve chamber 7 until the reverse cycle is resumed. However should this return flow of the fluid reach a certain intensity due to the action of a load on the platform J, the valve 15 is dragged against its seat, whereby the fluid can no longer flow from the chamber 9 to the chamber 8 freely but is slackened or braked by the throttle openings 18 which retard the rate of flow. The piston F supporting the load on the platform J (which load is not shown and may have any shape) is then prevented from coming down at an undue speed into the jack cylinder 11. Thus the descent of the lifting piston is automatically braked by throttling means incorporated into thestructure of the distributor.

'I'he return flow of the fluid from the cylinder ll to the reserve chamber 7 is checked or braked by ,the position of the enlargement 17 on the tappet rod 16 opposite the duct 6, as shown in Figure 5. The position and size of said enlargement are so arranged that it throttles the flow of fluid from the secondary or middle chamber 4 to the duct 6 and through the fore or primary chamber 5 even before the parts of the distributor occupy the respective positions shown in Figure 5 i. e. before the valve 15 has been applied upon its seat. The position of the enlargement 17 is so arranged that it causes braking action to take place before the valve 15 is dragged upon satisfactorily met by the improved fluid distributor since the operation of the pressure- responsive valves 14 and 13 located in the secondary and tertiary chambers 4 and 8 respectively is fully automatic under the flow of the fluid in the one or the other direction and under the timely action of the tappet rod 16 responsive to the actuation of the piston 1, while the valve 15A also functions automatically to cause the return flow of fluid to bethrottled through the narrow passages 18 as soon as said laf-named valve is applied on its seat by a fluid flow of predetermined intensity.

NumerousA constructional detailsof the structure might of course be changed withoutdeparting from the scope ofthe subjoined claims.

yWhatIclaim is; f 1. In combination with va hydraulic jack'ihaving a control pump connectedv with the fluid supply and with the jack cylinder,l a fluid distributor comprising. in co-axial alignment a primary chamber connected to the saidl supply, a. secondary chamber interconnected'to the primary chamber and control pump, and atertiary chamber interconnected to the secondary chamber and jack cylinder, pressure-responsive valves freely reciprocable respectively in the secondary and third chambers to or from seats in said chambers for permitting a flow of fluid from the supply to the control pump during the suction stroke of the control piston and from said pump to'said cylinder during its forcing stroke, the valve in the secondary chamber being capable of contacting with.the valve in the third chamber when unseated, means in the primary chamber for vunseating the valve in the secondary chamber responsive to said forcing stroke and then for causing the last named valve to unseat the valve in the third chamber when said ,forcing stroke is increased, and throttling means between the tertiary chamber and jack. cylinder, said lastcomprising in co-axial vertical alignment a primary chamber connected to'the said supply, a

secondary chamber linterconnected to the primary chamber and control pump, and a tertiary chamber interconnected to the secondary chamber and jack cylinder, pressure-responsive valves freely reciprocable respectively in the .secondary and third chambers to or fromseats in said chambers for allowing a flow of' fluid fromthe supply to 'the controlpump Iduring the suction stroke of the control piston and from said pump to said cylinder during its forcing stroke,v the valve in the secondary chamber being capable of contacting with the valve in the third chamber when unseated, a tappet rod movable through the control pump and primary chamber. and having an enlargement for throttlin'g the uid return flow from jack cylinder to supply respons-ive to said forcing stroke .While unseating the valve in the secondary chamber and then causing the last named valve to unseat the, valve in the third chamber when said forcing stroke is increased,b

and throttling means between the tertiary chamber and jack cylinder, said means being actuatable when said return flow reaches aypredetermined intensity. I

3. In combination with a hydraulic jack ,-having a control pump connected with the fluid supply and with the jack cylinder, a fluid distributor comprising in co-axial vertical alignment a primary chamber connected to the said supply, a secondary chamber interconnected to the primary chamber and control pump, and a tertiary chamber interconnected to the secondary chamber and jack cylinder, pressure-influenced valves freely reciprocable respectively in the secondary and tertiary chambers to or from seats in said chambers responsive to the direction of the fluid flow for allowing a flow from supply to control pump during the suction stroke of the control piston and a reverse flow from said pump to said cylinder during its forcing stroke, the valve in the secondary chamber being capable of contacting with the valve in the' third chamber when unseated, tappet means in the primary chamber co-related Ath'rottling to the action of the control piston for unseatlng the valve in the secondary chamber while throttling the fluidreturn flow from jack cylinder to supply responsive to said forcing stroke and while causing the last-named valve to unseat the valve in'the third chamberV when said forcing stroke is increased, and a quaternary chamber located between the tertiary chamber and jack cylinder and containing a return flow-'actuated valve,'the seat for this valve having narrow passages for the flow of fluid-'when the last-named valve is applied to its seat by a predetermined intensityof said return-flow.

v4. In combination with a hydraulic jack having a control pumpconnected with the fluid supply and with the jack cylinder, a fluid distributor vcomprising in co-axial vertical alignment a primary chamber connected'to said supply, a secondary chamber interconnected to the primary chamber and control pump, and a tertiary chamber interconnected to the secondary chamber and jack cylinder, said chambers being of increasing cross section to provide shoulders, pressureurged ball valves freely reciprocable to or from said seat-like shoulders responsive to the direction of the fluid flow so as to allow a flow from supply to pump during thesuction stroke of the control piston and a reverse flow from pump to jack cylinder during the forcing stroke of said piston, the valve in theI secondary chamber being capable of contacting with the valve in the third chamber when unseated, a tappet rod slidable through the primary chamber .and projecting into the pump for being co-related to the piston motions for unseating the valve in the secondary chamber responsive to the forcing stroke of the piston and for causing the last named valve to unseat the valve in the third chamber when said forcing stroke is increased, said rod having an lenlargement for throttlingv the fluid return flow during the last-named stroke, and a quaternary chamber located between the tertiary chamber and jack cylinder and containing a return flow-

Images