US1178996A - Hydraulic locking device for braking, adjusting, and other purposes. - Google Patents

Description

G. DUFFING.

HYDRAULIC LOCKING DEVICE 'F011 BRAK|NG,AD1UST|NG, AND OTHER PURPOSES.

APPLICATION F |LED MAR. 17, i910. 1 l 1,178,996, Patented Apr. 11,1916.

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' To all whom t may concern.'

UNITED srafrEs-rnTENr orribili I GEORG DUEEING, or iVILI-iEIM-oN-THE-EHINE, GERMANY.

HYDRAULIC LOCKING DEVICE ron. BEAKING, ADJUSTING, AND oTI-IEErUErosi-is.

Be it known-that I, GEORG DUFFING, of Illiilheim-on-the-Rhine, Germany, have invented certain new and useful Improvements in Hydraulic Locking Devices for Braking, Adjusting, and other Purposes, of

Awhich the following is a specification. e

This invention relates to locking or adjusting devices. Y

The ordinary forms of' adjusting and locking devices now employed usually consist of a piston located in a vhydraulic cylinder, in which all the free space inthe cylinder is completely filled with liquid, so that under certain conditions the piston is absolutely locked against motion in either di` rection. Such an apparatus must be so arianged'that the amount of liquid locatedL in the free space on one side of the pistonl is exactly equal to the amount ofliquid located-on the other side, when the pistony is in its'intermediate position. This necessitates a piston rod, or its equivalent, which extends through both ends of the cylinder, and also necessitates two stuiing boxes for the piston rod. In the ordinary devices em.- ployed, it is absolutely essential to keep the stuffing boxes tight, since a leakage of liquid from the free space detrimentally effects the operation of thedevice.

An object of my invention'isto produce* an adjusting and locking device, in which the piston rod of the operating piston eX- tends through one end only of the hydraulic cylinder, andv in whichthe stuffing boxes are not essential. y

A further object is to produce a l device of the character described, in which means are employed for simplifying and perfecting the operation of the'device. v

A further object is to "produce a device in which means are employed for automatically maintaining the necessary 'quantity of liquid in the free space of ythe hydraulic cylinder. v i Q 'f These, and other 4objects,-I attain in a d evice embodying' the features herein described, and illustrated in the drawingsaccompanying and forming. a part of this 'apf plication In the drawings, Figure 1 is a sectionalview of a constructional or Vdiagrammatic arrangement of a device embodying my invention. FigfQ is a sectional view and discloses a less diagrammatic arrangement of a device embodying theprinciple diepere.;

Specicatonof Letters Patent. l Patented ADL 11, 191@ Application filed-March 1'?, 1910. 4Serial No. 549,901.

een of the' deviceiiiuaraedin Eig. i. Eig.

'3 is a sectional view of apreferred form of' 'apparatus which embodies my invention; and Fig. 4 is a sectional view of a modified form of the apparatus shown in Fig. 3.

' In Fig. l, I have shown a simpleform of apparatus embodying mycinvention, which is capable of being rigidly' locked -against motion in eitherl or both directions, and is capable of permitting motion in one direction and ofbeing rigidly locked against motion in the other direction. The device consists of a` cylinder a closed at one end,

a hollow piston b located in thecylinder a and provided ywith a hollow piston rod o, the' interior ofl which communicates with the interior of the piston. The rod 0"' projects upwardly through an opening a formed in one 'endofgthe cylinder a and'itsl interior communicates with an equalizing receptacle or chamber va through ports m. The chamber a surrounds the rod c and is illustrated as being integrally formed with a collar or-fiange formed on the cylinder a aroundl the opening a. The receptacle n is adapted to beiilled with any suitable liquid, such as oil. and performsthe function vof an equalizing spaceforthe free' space on each Side of the pistonb within the cylinder a. With such an arrangement, it is not necessary "to provide a stuing boX for the rod '0, since any leakage fromy the cylinderv a will-.be received by the.y chamber n; It is',

however, essentialthat'the fit between'the rod Vand the opening afbe as c lose'as possible, so that the leakage will be' reduced to a minimum. Y v

In the vdevice illustrated, the upper end of the chamber a is shown open.' In devicesy adapted to operate in ya horizontal position,

itis necessary to: close the open end of the chamber n by means of a stufiing box or suitable packing gland. It will be apparent, however, that such an arrangement does not introduce thedifficulties encountered with.

devices of this character ordinarily employed, since pressure in the chamber fa is approximately equal to atmospheric pressure, and there is very'little tendency for the liquid to leakpast` the stuffing box or gland.

Ports are provided in each side of the piston' and forma means of communication between the free spaces inthe cylinder, above and below the piston, and the interior of the Piston' These Ports are' provided. with non-return valves d, lthe operation of which may be controlled by a cross-head g located in the piston and provided with an actuating rod f, which extends upwardly through the hollow piston rod and projects beyond it. The cross-head g is located between the stems of the valves l and is capable of being moved upwardly to open the upper valve ci,

and downwardly to open the lower valve cl. rIlhe cylinder t may be stationary, and-in the device illustrated, it is assumed to be stationary. The rod c is adapted to be connected at one end to an apparatus or an agent, which tends to move the piston either up or down, or which alternately tends tok move it up and down; and the device illustrated is adapted to control the movements of the apparatusor agent connected to the rod c.

The device operates in the following manner Let it be supposed that the rod c is connected to an actuating agent, which tends to alternately raise and lower the piston and that it is desired to have the actuatingA Y the influence of an upward force, but remains locked against downward motion by the practically incompressible liquid in the free space of the cylinder below the piston. When the piston moves upwardly in response to an 'upward force, transmitted to it by the agent or apparatus connected to the upper endfoi the rod c, a flow of liquid from the space above the piston into the interior of the piston takesplace through the upper port.v The upward motion of the cylinder causes the lower valve d to open and permits of a iow of liquid from the interior of the cylinder to the free space belo-w the cylinder. The liquid ejected from the free space above the piston is not suflicient to Iill the increasing free space below the piston, and, consequently liquid from the equalizing chamber n is drawn into the cylinder through the ports fm, and is delivered, past the lower valve cl, to the free space below the piston. If, during the upward motion of the piston, the actuating force on the rod c is reversed, the lower valve l will be immediately closed, by a reversal of the ow of liquid through the port it controls, and will preventv a downward'motion of the piston I), since it will coniine the liquid in the free spa-ce below the piston, After the piston has risen the determined amount, the upper valve Z will be automatically closed, since its valve stem will be raised ofi vof the cross-head q. This will lock the piston against further upward motion, since the liquid in the free space above it is confined.

If it is desired to permit a downward motion of the piston, the cross-head g is moved downwardly to open the lower valve d, so that the liquid below the piston may be discharged into the interior of the piston. The downward motion of the piston will cause the upper valve (Z to open and will also cause liquid to enter the free space above the piston, through the port controlled by that valve. The liquid discharged from the free space below the cylinder is more than is necessary to fill the increased free space above the piston; consequently, the excess liquid is delivered to the chamber e, within the rod c, or to the chamber a, through the ports m.

In the constructional form shown in Fig. 2, the hollow piston rod c again forms the equalizing space e, which is in constant communication with the interior of the piston l). In this case, however, the equa-lizingv space e is capable of communicating with the free space in the cylinder above and below the piston Z), not only through the valves Z but also through the passages z' controlled by the slides 7L on the rod f. In this construction, if the adjusting rod f is moved it does not, as in the previous example, positively open certain of the valves d, but it is provided with cylindrical slides 71, snugly guided in the hollow piston rod c and adapted to open or to close the passages z' leading to both cylinder-chambers. For instance, on moving the adjusting rod f in the downward direction so as to open the lower passages v while closing the upper passages z', the locking or braking piston is free to follow the downward movement, as the liquid driven from the free space in ,thek cylinder below the piston escapes in the direction of the arrows 7c and Z as shown, partly into the free space in the chamber above the piston and partly into the equalizing space e. If the adjusting rod f is raised, the upper passages z' are opened andthe lower passages i are closed. The piston Z) is then free to follow the upward movement and the liquid driven from the free space above the piston enters the free space below the piston, and an auxiliary supply of liquid is also delivered to the free space below the piston from the equalizing space c.

In the constructions shown in `Figs. l and 2 the equalizing tank or space e is in constant communication, for instance, through ports m in the hollow piston rod c, with a receptacle n which receives any liquid that may escape therein owing,Vr for instance, to leakages between the `piston rod and its guide. Such liquid thus flows back into the equalizing tank and from the latter again passes into the braking or locking cylinder a.

Consequently no absolutely tight stuffing lli) boxes need be provided on the piston rod guide. As already stated, the arrangement of the equalizing tank e may be used also in connection with all kinds -of hydraulic brakes.

A further constructional form is shown in Fig.- 3. lIn this case the valves d arranged within the hollow piston b are atx-- ially movable along the surface of-a slide h and are provided with controlling edges o cooperating with` thosegon the slide fh.

The common valve seat is constructed iny the forni ofa simple ring p held in place by a screwed-in piston coveror end 'w and against which thel valves d are pressed by. springs g. The slide h. forms part of the adjusting rod f', and is provided with recesses 1 for the passage of the locking liquid.

The equalizingtank e subjected, for in stance, to atmospheric pressure, is inv constant communication with the spaces??7 located between the two valves through passages fm, and s, Vas well as through passages t" means of its controlling edges 0 will create a free passage forthe liquid. The locking follow the upward piston b is thus 'free' to movementv and the liquiddisplaced thereby from the upper cylinder-chamber 'escapes through the passage between the upper con trolling edges o and through the lower valve d intoY the lower cylinder-chamber, the required e for equalizing quantity of liquid purposes being supplied fromthe equalizing tank e( Theniore the piston approachesits new position of rest, the more the controlling edges o are closed. The reverse is the case if the Vadjusting rod f and theI slide, It are moved in the constructional form according to Fig. j 3, provision moreover is made ofrelastic inter- Y mediate members, such as for instance pres-A sure springs v interposed between the `ad-,. justing rod and the locking piston and its rod or extension. These elastic intermediate members have the tendency to constantly maintain the adjusting slide h in its central position withinthe locking piston and to render the speed of adjustment dependent in a favorable manner on the force acting on the slide ro'd,'for it will be seen that on the force of adjustment increasing, the free cross section for the passage of the lockingv liquid is simultaneously Vincreased so that from both causes the piston moves in a more rapid manner. f Y

is in communication the cylinder above through the'` ports u;

l to an y. upward fforce.

downward direction. In the can supply.

always in communication with the interior' t represents a constructionalform of the invention in which the adjusting slidelz,2 is guided within the hollow :locking piston-2')2 so as to be completely `relieved of locking liquid pressure. The slide 'h2 is in effect a hollow piston valve and is provided with an upper and lowerv series of' ports 02, eachof which communicates with. the interiorl of the valve and is respectively controlled bythe upper and lower valves d2. Each valve d2 is annular and surrounds the slide or piston valve h2, and is held to its seat on the ring p2 by the coiledV spring q2. An annular ange m2 is provided on the inner face of each end of lthe piston b2 and these flanges coperate with the'valves. (Z2 informing an inclosing cage for the slideor piston valve h2. Y located between the valves cl2',y when the slide h2 is in the normalY or intermediate position, and the flow of liquid thro-ugh them is controlled b thevalvesdZ.v The hollow piston rod cgis constructed so as to forni the equalizing tank e2, or it may terminate upwardly in an equalizing tank or.

space, yif desired. As in the previous case, pressure springs o2 are interposed'between Vthe slide h2 and the locking piston vZ22 to cause the slide to always maintainits central position when the adjusting rod-isffree. `llhenthe adjusting rod f2 is moved upvwardly,` the upper series of ports 02 are raisedabove the upper edges of the valves A seriesof ports y2 are'V (l2. This places the interior of the slide h2' in communication withthe free space inthe cylinder a2, above the piston b2, and permits the piston b2 to move upwardly in response During the upward motion ofthe piston, liquid enters its interior from the free spaces in the upper portion of the cylinderaf", through vthe ports u2, and passesthroughfthe upper series of portsf02, throughthe interior of the slide h2,

through the ports l1/2, past thelower valvesl d?, and out through-the :lower ports u2 into the freeV space; injthe cylinder belowpthe piston '62. Thel preponderance of liquid pressurek above the lower valve d? over the liquid pressure below the valvev issufcient to openthe valve against, the force vof its closing. spring, during this upward motion o-f the piston, and an Aauxiliary supply of liquid will be delivered frointhe space e2 into the :free space below the piston, to supply the excess demand for liquid beyond that which the free space above' the piston The equalizing space e2 of the slide 71.2. ywardly, in response carries with it the upper valve (Z2, and consequently moves .the valve to close the upper ports 02. y piston 52 is `again locked against As thek piston b2 moves up- 'to the upward force, it.

roo

ica

Whenthe yports, 02 are closed, .the j motion.

"When therodf2 is moved downwardlyto 18e .l der, a hollow piston open the lower series of ports o2, the piston b2 is capable of being moved downwardly, and liquid is discharged from the freespace below the piston into the free space above the piston, and also into the equalizing spacey cf. During this motion of the piston b2, the upper valve Z2 is automatically openedy by the preponderance of liquid pressureV below it.

In any of the cases hereinbefore described, the liquid of the equalizing tank may be supplied either at atmospheric pressure or, if desired, under high or low pressure, as will be easily understood.

I claim:

l. A hydraulic braking device, comprising a cylinder, a piston mounted for movement within the cylinder and having valved passages formed therein and communicating with the free spaces at the ends of the cylinder, van equali'zing space for delivering liquid to or receiving liquid from the passages of said piston during relative motion between the piston and the cylinder', and means mova'bly mounted within the piston for controlling the operation of the valves of said passages.

2. A. hydraulic braking device, comprising a. cylinder, a piston mounted for movement within the cylinder and' having passages formed therein communicatingf with tghe free ends of the cylinder, an equalizing space communicating with the piston passages and formed within the piston rod, valves for controlling the delivery of fluid through the piston passages, and means slidably mounted within the piston and movable relative thereto for controlling` the operation of said valves.

3. In a hydraulic braking device, a cylinmovable with relation to the cylinder and so located therein as to confine Vin opposite ends of the' cylinder bodies of liquid which take no part in the act of moving the piston, passages formed in the piston for transferring liquid from one of the bodies to the other,v an equalizing space communicating with said passages for delivering liquid thereto or for receiving liquid therefrom during relative motion between the piston and the cylinder, valves for controlling said passages, and means movable with relation to both the piston and the cylinder for controlling the operation of said valves.

4. A hydraulic braking` device, comprising a cylinder, a. piston mounted for movement within the cylinder, and having passages formed therein and communicating with the free spaces at each end of the cylinder, a hollow piston rod for said piston with its interior passage in communication with said piston passages, oppositely disposed valves for controlling thedelivery of liquidv .trom and to the free spaces of thecylinder through the piston passages, an equalizing space communicating with the interior of the piston rod, kand means for controlling the operation of the valves and communication between said equalizing space and the free spaces of the cylinder.

5. In a hydraulic braking device, a cylinder, a hollow piston located within the cylinder movable with relation thereto and provided with valved passages communicating with the interior of the cylinder and with an equalizing space located within the piston rod of said piston, valves for said passages, an adjusting' rod located within the hollow piston rod and a crosshead mounted on the adjusting rod and located within the piston for opening said valves.`

6. A hydraulic braking device, comprising a cylinder, a piston'mounted within and movable relative of the cylinder and having passages formed therein communicating with each free space of the cylinder and with a passage provided through the piston rod, an` equalizing space communicating with said piston passages through the piston rod, oppositely disposed pressure responsive valves for controlling the delivery oi' liquid through the piston passages, valve means slidably mounted within the piston for controlling the operation of said valves and for controlling communication between said passages and said spaces, and means extending through the piston rod for actuating said valve means. l

7. In a hydraulic locking or braking device, a cylinder, a hollow piston located in said cylinder and' provided with an equalizing space, and passages extending through the wall of the piston and communicating with the interior of thevpiston and the free space in the cylinder above and below the piston, valves controlling said passages and means reciprocable within said piston and relatively thereto for actuating said valve.

8. In a hydraulic locking or braking device, the combination with an equalizing receptacle, of a cylinder, a hollow locking or braking piston located in said cylinder and provided with passages connecting the interior of the piston with the free space in the cylinder, valves located in saidv piston, an adjusting rod, and a slide mounted onsaid rod and provided with passages located between the slide and said valves for the passage of liquid between the equalizing receptacle and the piston. 1

9. In a hydraulic locking or braking device, the combination with an equalizing receptacle, a cylinder, a hollow piston provided with passages connecting the interior ofthe piston with the free spaces of the cylinder, a piston Vrod secured to the piston and provided with an interior passage, communicating with the interior of the piston and said receptacle, valves controlling the passages in the the valves, valves and on which the valvesjare guided, and an adjusting rod on which said slide is mounted. v

10. In a hydraulic locking or braking device the combination with an equalizing receptacle of a hollow locking or braking piston, Valves controlling the passage of the liquid between the equalizing receptacle and hollow piston, a slide coperating with said valves and slidable relatively to said piston, and means Vfor yieldingly supporting `the said slide and tending to hold the same in piston, a slide coperating withV said central position within the piston, substantially as set forth.

' 11, In a hydraulic locking or braking device the combination with an equalizing receptacle, of a hollow locking or braking piston, valves controlling the passage of liquid between the equalizing receptacle and hollow piston, a slide coperating with said valves and springs interposed between` the Copies of this patent may be obtained for a valve seat common toy axially 'trolling the passagesl iive cents each, "oy addressing the Washington, D. G.

said slide and the walls of the piston, an ada justing rod for operating said slide, a tubular guide for said adjusting rod, and springs interposed between the adjusting rod and the said tubular guide substantially as and for the purpose set forth.. l

j 12. In a hydraulic locking or braking de-` vice, ythe combination with an equalizingreceptacle ofa hollow piston communicating with said equalizing receptacle, Valves confor the liquid between said piston and receptacle, springs for yieldingly supporting said Valves, a slide coperating with said valves and springs interosed vbetween both Jfaces and the adjacent walls of the piston, all substantially as described. j

In testimony whereof I aiix lmy signatureY in presence oftwo witnesses. 1 i GEORG DUFFING.

Witnesses:

Louis VANDORY, Bnssm F. DUNLAP.

Commissioner of I Eatents,

of the said slide-

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