US2550674A - Supporting column - Google Patents

Description

I May 1, 1951 J. c. CURTIS SUPPORTING COLUMN 2 Sheets-Sheet 2 Filed April 21, 1944 0 0 6 a? WZM 7 7 $200220?) claim 5. (242 2215.

Patented May 1, i951 John-r13. Curtis, .Claremont, N. :assignor to Joy Manufacturing Company, a corporation of Pennsylvania Application April 21, 1944,, Serial No. 532,173

. 19 Claims. 1

,My invention relates to :supporting .columns,

and more particularly to means for delivering I liquid under ap-nessllre to :an extensible supportme column :of the hydraulically actuated :type,

and-tothezstnuctural iieatures :oisuch-a column.

Inlsettingup.assupportinglcolumnLitisdesirable i hat the operator .xbe :iree to .guide ithe abutment engaging members of the .zoolumn while (the lat- Iter, is ibeing extended by fluid .;delivered to it zunder pressure. Mter lthe:abutmentsurlaces havezbeen engaged and 'the column is supported without the aid of alihe operator, the operator :may .then .do

"whatever :is necessary .to increase the abutment en agin pressure for holding :the column firmly ih'the desired :position. :To effect the extending T the zcolum-n into engagement with 1the abutment sn iaces there :may :be provided a motor actuated epumpingmeans vvormeans for ssubjecting a may @omiquid i110 pressure for forcing the :-1 atter "toisnistons which operate .to extend the column.

If *the pressureat which :the liquid is delivered to the pistons is :not sufiioient :to :hold :the column inrthe edesired p ition when :the latter :is sub.-

ie ed 2 1 the l ds to be placed :upon .it, then some suitable manually actuated .means .may ;be

provided ifQr increasing the abutment engaging :pressure. When :the 10011111111 ;'-is :held extended only by the .1-iquid {delivered to :.it, .it will :.be appreciated that any leakage of liquid from .the

C mn w uld permit the lett r tO CQ11 DSB-lun- .less additional 'sliguid was supplied. jBy maint n ng a continuous c nnection Ebetween the motor actuated pumping means iand its supply :of in crating .fiuid. the pumping means :will oper- "ate and deliver liquid to :the column until the lat. ,r :can extend :nofurither tunderithe discharge pressure of :the vpumping means. :The pump in means will when stall, ihut, iaiS.SO0I1 as j liquid leaks from zthercolumn, :the pumping mean will automaticallystart-againand pumDliquid-to the column :nntil the maximum :abutment engaging ---pr.e ssure-3isagaimreached. o' If-the-oolumnisforced my invention is to provide *improved means for .delivering fiuid underpressurekto aefiuidractuated .2 I x device. A further object of my invention is to provide an improved hydrauliccolumn having improved cneans for .automatically preventing collapse thereof due to leakage. Yet another object of my invention is to provide an improved fluid actuated pump. These and other objects of the invention will'appear more fullyin the following descrip'tion.

"In the-accompanying drawings there arershown for purposes -of illustration one form :and two modifications which the-inventionmay assume in practice.

In thesed-rawings:

Fig. 1 is a front elevational viewof an illustrative embodimentof my improved supporting column.

Fig. '2 is a view in longitudinal vertical section taken through the supporting column shown in Fig. l.

Fig. 3 is an enlarged vertical sectional :view showing a portionof the supportin column and improved means for pumping liquid froma liquid storage chamber to passages leading to fluid actuated pistons of the column, the "view being taken-on :the plane of the line 3-3 of Fig. 1.

Fig. 4 is an-enlarged =vieWtaken-on the plane of theline--'4'4 of Fig. l-showingaportionof the supporting column in section and the remainder in plan.

-5 is -a fragmentary sectional view taken on the planeof "the line 5-5 of Fig. 4 and show i-ng valve means for controlling the venting -of fluid from the fluid actuated "pistons of the column to the storage-chamber.

Fig. "6 is a-front elevational view'showing a-portion of a modified form of the invention.

Fig. *7 is an enlarged vertical sectional view taken on the plane of the line .1-'1 of Fig. '6. v

Fig. '8 is a verticalsectional view showing a modification of the fluid actuated pumpingmeans of the form of the inventiOnshOwninFigs. 1 to 5.

Inthe illustrative embodimentof theinvention shownin Figsll to 5, inclusive, the improvedsupporting column is generally designated l and comprises .a body portion 2 having laterally spaced ,bores 3 and 4 opening through its lower end, and a bore .5 located between ,the bpres f3 1 at its lower end, with a-reduced bore [0 opening into the bore 5 to form a chamber space 12 for containinga body of liguid, such asoil. -Recipro-' cable within the bores 8 and "4, respectively; are

3 pistons l4 and I5 carrying piston rods I6 and I! which extend through bushings l8 attached, as by bolts IE], to the body portion 2, and the piston rods have fixed to their lower ends abutment engaging members and 2|.

Attached to the side of the body portion 2, as by bolts 23, is a cylinder block 24 having stepped coaxial bores 25 and 26 communicating with each other at their adjacent ends. Reciprocable within the bores 25 and 25 is a piston 28 having an enlarged head portion 29 fitting the bore 25 and a reduced head portion 33 fitting the bore 26. A passage 3| extends through the body portion 2 of the column and the cylinder block 24 to connect the chamber space |2 in communication with the lower end of the bore 26, and a spring pressed ball valve 33 opens to permit liquid to flow through the passage 3| toward the bore 26 and closes to prevent flow in the opposite direction. A passage 34 opens into the bore 26 at a point between the ends of the latter and communicates with the passage 3 lat a point between the valve 33 and the chamber l2. Formed in the reduced head portion 33 of the piston 28 is a passage 35 opening through the lower end of the head portion 38- and opening through the side of the latter at a point to communicate with the passage 34 just before the piston 28 reaches the lower end of its stroke. The lower end of the bore 26 is connected under the control of a spring pressed ball valve 3'| with a passage 38 which communicates with branch passages 39 and 40 opening, respectively, into the upper ends of the bores 3 and 4. It will be seen that when the position 28 is caused to re ciprocate, the head portion 30 will operate to pump liquid from the chamber |2 to the bores 3 and 4. As soon as the bore 26 is connected to the chamber I2 through the passages 34 and 35 the pumping stroke terminates and the pressure beneath the piston drops permitting the latter to be moved more easily to the lower end of its stroke.

a The upper end of the bore 25 is closed by a cylinder head 42, and a spring 43 acting between the lower side of the piston head portion 29 and the cylinder block 24 at the lower end of the bore 25 normally holds the piston 28 against this cylinder head. The space at the lower end of the head portion 29 communicates continuously with the atmosphere through a vent port 44. Formed within the cylinder headis a valve chamber 45 containing a piston type distributing valve 46 for controlling the supply of pressure fluid through a passage 48 to the cylinder bore 25 and for controlling the venting of fluid from the bore 25 through a passage 58. The passage 48 opens into an enlarged portion 5| of the valve chamber at a point to be covered by'one end of the valve 46 when the latter is in one of its limiting positions, and a fluid supply conduit 52 opens into the chamber portion 5| at such a point that fluid supplied to the chamber must flow around a flange 54 on the valve 43 in order to reach the passage 48. The end portion 55 of the valve adjacent the passage 48 is slightly reduced in cross section to present an annular area 56 which is somewhat larger'than the area 51 at the opposite side of the flange 54. It will be seen that with the valve in its open position, as shown in Fig. 3, a flow of fluid through the chamber portion 5| toward the passage 48 will act on the flange 54 to urge the valve toward .its closed position and, if the flow of fluid becomes great enough, the force acting on 4 the valve will be sufiicient to move the latter to its closed position. With the valve closed, the pressures at opposite sides of the flange 54 become equal, and the pressure acting against the larger area 56 tends to move the valve to its open position against the pressure acting on the area 51.. The exhaust passage 53 opens into a chamber space 59 surrounding a reduced portion 68 of the valve 46, and the space 59 is connected, when the valve is seated, past the outer end of the reduced portion 60 to an exhaust port 6| in the cylinder head. On the valve 46 at the inner end of the reduced portion 60 is an annular area 62 which is subjected to the pressures in the bore 25 for opposing opening movements of the valve by the pressure acting on thearea 56. Opening through the wall of the cylinder bore 25 is an exhaust port 63 which is so located that it is uncovered by the side of the piston portion 29 shortly after the passage 35 has been connected in communication with the passage 34.

The operation of the mechanism so far described is as follows: After the column has been placed in the desired position, the operator connects the conduit 52 in communication with a pressure fluid supply, as by opening a suitable valve not shown. If. the valve 46 should be in its closed position, the fluid pressure builds up in the chamber portion 5| and acts against the valve area 56 to move the valve to its open position for supplying fluid to the bore 25 through the passage 48 and for cutting off the exhaust of fluid through the passage 58. Until the valve opens, the area 62 is subjected only to atmospheric pressure and but little resistance is offered to the opening movement of the valve. As soon as the valve opens, the end portion 55, as well as the area 56, is subjected to the pressure in the bore 25, and the valve is held open even though the pressure in the bore acts on the area 62. The pressure fluid acts in the bore 25'against the top of the piston 28 and forces the latter downwardly against the action of the spring 43. Just before the piston reaches the-lower end of its stroke, the bore 26 is connected through the passages 35 and 34 to the chamber l2, reducing the pressure which opposes the downward movement of the piston. The pressure in the bore 25 then forces the piston downwardly until the exhaust port 63 is uncovered and the bore 25 is freely vented to atmosphere. The reduction of the pressure in the bore 25 results in a rush of fluid through the valve chamber portion 5|, and the action of this fluid on the valve flange 54 causes the valve 46 to be moved to a position covering the passage 48 and opening the exhaust passage 58. The piston 28 is then moved upwardly by the spring 43 as the pressure fluid escapes from the bore 25 'through the exhaust passage. The escaping pressure fluid acts on the area, 62 holding the valve closed against the force of the line pressure acting on the area 56. When the piston reaches its uppermost position, the pressure acting on the area 62 reduces rapidly and the valve 46 is unseated by the pressure acting on the area 56 to supply pressure fluid again to the bore 25. The reciprocation of the piston 28 causes liquid to be pumped from the chamber l2 through the passage 3|, past the ball valve 33, through the bore '26, past the ball valve 31, through the passage 38 and the passages 39 and 43 to the bores 3 and 4 where it acts on the pistons I4 and I5 and effects an extension of the column until the abutment engaging members 8,

essence 2D and 2| are firmly in engagement With-abut 'ments. The supply of pressure fluid through the conduit "52 is maintained while the column is in use, so that the pump will automatically introduce more fluid into the cylinders 3, 4, whenever there is any leakage such as to reduce the pres-' sur' 'tnerein.

when it isdesired to lo'wer the eomm'n, the supply of fluid through the conduit 52 is interrupted and 'a valve 65, as shown in Fig. 5, is manually adjusted to connect a passage 66, leading from the "passage 38, in communication with a passage 61 opening into the chamber i2 In Figs. 6 and 7 there is shown a modification of the invention in which a, manually operated pump, generally designated 1, is provided 'for pumping liquid from the chamber ['2 through the passages 31 and 38 to the bores 3 and 4. v The pump 1!] comprises a cylinder member "H fitting Within "a bore 12 in a cylinder block 13 attached 'to the side of the body portion 2 of the column I and having a bore 14 "containing a piston 15. The passages 3| and 38 communicate with the bore M under the control of the spring pressed ball valves '33 land. 31, respectively. The upper end of the piston is pivotally connected at Hi to an operating lever 11, and theoperating lever is lpivotally connected, at a point spaced longitudinally of the latter from the point 55, to one end of a link 18 which is pivotally connected at its other end to a collar 86 clamped, as shown in Fig. 7, "between a flange 3| on the cylinder member II and a collar 82 threaded on the cylinder member.

in order to obtain a rapidextension of the olumn, there is provided a conduit 83 opening into the chamber i2 above the surface of the liquid therein and adapted to be connected by amanually operated valve 8-4 to a pressure fluid supply. -,In setting up the column, the valve 84 is opened to supply pressure fluid to the chamber I2 for forcingliquid from the latter through the passages 3| and 33 to the bore 3 and 4. After the abutments have been engaged by the members B, and 2:, the valve 84 is closed and the pump lever T! is operated to actuate "the piston 15 for forcing a little more liquid to 'the bores 3 and 4 andefiecting a, very powerful engagement of the abutments.

Fig. -8s-hows a fluid actuated pump similar to thatof Fig. 3, but in this case the piston 28 is provided with a portion BBbetween the head portions -2'9 and and fitting a bore 85 which is somewhat larger than the bore 26 butis smaller than the bore 25. Aconduit 88 supplies pressure fluid to a passage 89 opening into the lower end of the bore 86, and this pressure fluid acts on an annular area 8? on the piston portion 85 for yieldingly urging the piston toward the cylinder head-42. The distributing valve 46' controls the flow-of pressure fluid relative to the bore 25 for e'fiecti-ng, in the same manner as that described inthe first form of theinvention, the reciproca tion of piston 28. In this case the distributing valve has a reduced portion 90 which is somewhat smallerthan the openings! connectingthe space 59 with the exhaust port 6|. At the outer end of the-portion 90 is an enlarged portion 92 which moves into the opening 9| with just enough clearance to provide a restricted openin to exhaus t when the valve is in its, closed position. l'ay appropriately selecting the area of the portion92 relative to the area ofjthe face 93 'on'the body of thevalve, a substantial holding s rcerer keeping the valve seated can be provided, while at the same time a clean-cut opening movement of the valve may 'be insured because as the valve opens an increased venting passage area "is provided at its left hand end as the portion 92 moves out'of the opening 9| and the smaller portion -90 extends through the opening.

As a result of "my invention, it will be noted that'there is provided an improvedfiuid 'actuated supporting column having improved means for delivering to the column, a fluid under pressure. While the column shown herein is extended by an incompressible fluid, it will be understood that the fluid delivery means associated with the column is adapted for use in the delivery of a gaseous fluid. It will be noted that by reason'of theprov'ision of the fluid delivery means, the operator is free to support the column in the desired position as it is "extended into engagement with extraneous abutments. With the pressure generating means operating automatically to compensateior any pressure drop in-the support ing'column, it will be seen that the pressure 'will be maintained and the column will not collapse because v of the leakage of fluid therefrom. A rapid extension of the column is obtained by the subjection of the body "of liquid to a continuous pressure, and, if further extension is neededunder increased pressure, such extension "may be quickly "obtained by manually actuated 'means Because of the provision of a plurality of abutment engaging member's-at one end'of the column, these members beingactuated by separate'pis'tons to which fluid is delivered from a common source, there Will be an automatic adjustment of "the members to compensate 'for unevenness in "the abutment surface.

While there are in this application "specifically described one form and two modifications which the invention may assume in practice, it will be understood that "these are "shown for purposes of illustration and that the invention may be further modified and embodied in various 'oth'eriorms Without departing from its spirit or the scope-of the appended "claims.

Wh'at'I claim as new and desire to secure 'by Letters Patent is:

1. In a'fsupporting column, in combination, a body meinberhaving parallel, offset bores Opening through opposite ends thereof, a tubular shaped member fixed at one end withinoneof said bores and having ran abutment engaging member at its outer end, a piston reciprocable within another of saidbores and'ca'rrying'a piston rod to the'outer end of which an abutment engaging member is attached, said tubular "memoer cooperating with said body'memb'erto form a liquid storage space, and means "for delivering liquid under pressure from said storage space to said piston ffor effectingrelativemovement of said abutment "engaging members into engagement with extraneous abutments.

2, In a supporting column, in combination, 'a body member having a centrally located bore opening through one 'end thereof, a -tubular shaped memb'erfixed atone end Within'said'bore andp'rojecting from said body member, an abut me'ntfengaging member attached to the outer end of said tubular member, a plurality'of'bores opening through the opposite end of said body member and arranged in parallelism with said centrally located bore and spacedequi-distantly from the latter at the opposite sidesof said body member, pistons reciprocable Within said'plurab ity of'bore's"fa'nde'ach carrying a piston rod to the outer "endof "which "an abutmentenga'ging member is attached, said tubular member cooperating with said body member to form a liquid storage space, and means for delivering liquid under pressure from said liquid storage space to said pistons for effecting relative movement of said abutment engaging members into engagement with'extraneous abutments.

3. In a supporting column, in combination, a body member having a centrally located bore opening through one end thereof, a tubular shaped memberfixed at one end within said bore and projecting from said body member, an abutment engaging member attached to the outer end of said tubular member, a pair of bores opening through the opposite end of said body member at points spaced equidistantly from opposite sides of theaxis of said first mentioned bore in parallelism with the latter, pistons reciprocable within said pair of bores and each carrying a piston rod to the outer end of which an abutment engaging member is attached, said tubular member cooperating with said body member to form a liquid storage space, and means for delivering liquid under pressure from said liquid storage space to said pistons for effecting relative movement of said abutment engagingmem bers into engagement with extraneous abutments; said last mentioned means including'common passage means communicating with said pair of bores. U W Y 4. An extensible column comprising, in com bination, a member providing a bore, a piston reciprocable in said bore for varying the length of said column, means for delivering fluid under pressure to said piston for effecting an extension of the column, said last mentioned means including stepped cylinder bores opening into each other, a piston having portions reciprocable in each of said cylinder bores, one of said piston portions acting as a pump piston and the other acting as a motor piston, valve means for controlling the supply of operating fluid to said motor piston, means for yieldingly opposing movement of said motor piston by the operating fluid supplied thereto, means for venting fluid from said motor piston at the end of the working stroke of the latter, fluid supply and discharge passages for conducting fluid relative to said pump piston, inlet and discharge valves for controlling the flow of fluid through said supply and discharge passages, and passage means for connecting the working end of said pump piston to said fluid supply passage at the supply side of said inlet valve shortly before the end of the pumping stroke is reached.

5. An extensible column comprising, in combination, a member providing a bore, a piston reciprocable in said bore for varying the length of said column, means for delivering fluid under pressure to said piston for effecting an extension of the column, said last mentioned means including stepped'cylinder bores opening into each other, a piston having portions reciprocable in each of saidcylinder bores, one of said piston portions acting as a pump piston and the other acting as a motor piston, valve means for controlling the supply of operating fluid to said motor piston, cans for yieldingly opposing movement of said motor piston by the operating fluid supplied thereto, means for venting fluid from said motor piston at the end of the working stroke of the latter, fluid supply and discharge passages for conducting fluid relative to said pump piston, inlet and discharge valves for con trolling the flow of fluid through said supply and discharge passages, and means for venting the space at the working end of said pump piston shortly before operating fluid is vented from said motor piston.

6. In a supporting column, in combination, a body member having bores opening through opposite ends thereof, a tubular shaped member fixed within one of said bores and having an abutment engaging member at its outer end, a piston reciprocable within anotheiz of said bores and carrying a piston rod to the-outer end of which an abutment engaging member is attached, said tubular member cooperating with said body member to form a liquid storage space, means for delivering liquid under pressure from said storage space to said piston for effecting relative movement of said abutment engaging members into engagement with extraneous abutments, said last mentioned means including a cylinder bore containing a reciprocable piston, valve controlled passage means connecting said cylinder bore in communication with said liquid storage space and with said first mentioned piston, means for effecting reciprocation of said last mentioned piston, and means for subjecting the surface of the liquid in said storage space to the action of a pressu'r'dfluid.

7. A pump, mechanism comprising, in combination, means providing a cylinder bore, a piston reciprocable in said cylinder bore, means for 'yieldingly urging said piston toward one end of said bore, means for supplying operating fluid to one end of said piston for forcing the latter through working strokes against the action of said yielding means, means for venting operating fluid from said piston at the end of its working strokes, valve controlled supply and discharge passages for conducting fluid to be pumped relative to an area at the opposite end of said opposite end of said piston, and means for venting fluid from said piston areashortly before the end of the working stroke of said piston is reached.

8. A pump mechanism comprising, in combination, means providing stepped cylinder bores opening into each other, a piston having portions reciprocable in each of said bores, means including a valve for controlling the supply of operating fluid to one of said piston portions, means for yieldingly opposing movement of said piston by the operating fluid supplied thereto, means for venting operating fluid from said piston after a predetermined movement of the latter, fluid supply and discharge passages for conducting fluid to be pumped relative to the other of said piston portions, inlet and discharge valves for controlling the flow of fluid through said supply and discharge passages, and means for venting fluid from the other of said piston portions shortly before operating fluid is vented from the first of said piston portions.

9. A pump mechanism comprising, in combination, means providing stepped cylinder bores opening into each other, a piston having portions reciprocable in each of said bores, means including a valve for controlling the supply of operating fluid to one of said piston portions, means for yieldingly opposing movement of said piston by the operating fluid supplied thereto, means for venting operating fluid from said piston after a predetermined movement of the latter, fluid supply and discharge passages for conducting fluid to be pumped relative to the other of said piston portions, inlet and discharge valves for controlling the flow of fluid through said supply and discharge passages, means for venting fluid from the erating. fluid. is vented from the first of. said. pis.--

ton portions, said last mentioned means including'aventpassageiopening into thebore contain ing the other of said. piston. portions, and passage means: extending through theother of said piston portions: and: communicating. with. said vent passage shortly before the end of the. pumping strokeof; said. piston.

101.. A. pump mechanism comprising, in combination, means providing. stepped cylinder bores opening into each other, a piston having portions reciprocable in each. of said bores, means includingra: valve; for controlling the supply of operatingi fluid. to the largerone of. said piston portions, means for yieldingi-y opposing movement of. said piston by the. operating fluid Supplied thereto, means for venting operating fluid. from said larger piston. portion after a predetermined movement. ofythe. latter, fluid; supply and discharge passages for. conducting fluid to be pumped rela tiveto the smaller of ;said. piston: portions, inlet and discharge valves for controlling. the flow of fluid. through said supply and discharge passages, and; means: for venting fluid. from the smaller of said piston portions shortly before operating fluid is vented from the. larger one of said piston piston by the operating fluid supplied theretomeans for venting operating fluid from said larger piston portion after a predetermined movement of the latter, fluid. supply and dis charge; passages for conducting; fluid to be pumped relative to the smaller of said piston portions, inlet and discharge valves for controlling the. flow of fluid through said supply and discharge. passages, means for venting fluid. from the smaller of said piston portionsshortly before operating fluid is vented from the larger one of said piston portions, said last mentioned venting means including a vent passage opening into the smaller 0t said cylinder bores between the ends of the: latter, and passage means in said smaller pistonpo-rtion adapted to communicate with said vent passage before the end of the working. stroke of said piston is reached. I

12. A pump mechanism comprising, in com bination, means providing three coaxial cylinder bores decreasing progressively in diameter, the middle one of said bores opening into the other two, a piston having portions reciprocable in each of said bores, means including: a valve for. con-' means for venting fluid from the smaller one of said piston portions shortly before operating fluid is vented from the larger one of said piston portions.

13. A pump. mechanism comprising, in. combination, means; providing av cylinder bore, a. piston reciprocable insaid cylinder bore, valve means for controlling the supply of? operating fluid to and the. exhaust of fluid from said cylinder boreat one end of said. piston, said valve means movable to its. exhaust effecting position on the venting of operating fluid. from said bore, means for venting operating: fluid from: said bore at the end of. the. working stroke of said piston, means for yieldingly opposing movement. of said piston by the: operating fluid, valve controlled. supply and discharge passages for conducting fluid to, be

pumped relative to an area at the opposite. end of said piston,,and. means for venting fluid. from said piston area shortly before the end. of the. working, stroke of said piston is reached.

145A pump mechanismv comprising, in com.-'

bination, means providing steppedcylinder bores opening into. each other, a piston having portions. reciprocable in each. of said bores, valve means: for controlling the supply of operating fluid to andt'the exhaust of fluid from one of said bores, said valve. means movable to. its exhaust effect.- ingpositionl on the venting of operating fluid from said bore, meansfor venting operating. fluid fromv said here after a predetermined. movement of said piston in its. working stroke, means supplying pressure fluid to another of said bores for opposing; movement of said pi'stonby the operating' fluid. supplied thereto, fluid supply and dis:- charge passages for conducting fluid to be pumped relative to another of said bores. inlet.

and: discharge. valves. for; controlling the. flow of fluid; through said supply and discharge passages,-

and. means. for venting fluid from the. last. mentioned oneof said bores shortly before operating fluid is vented. from the. first mentioned one of said bores. i

15:. In a supporting column, in combination, a lower frame, an elongated uprightv support secured: to. said frame. midway between the sides of the latter and" having a roof engaging member at: its upper end, a pair of extensible hydraulic cylinder and piston devices secured to frame and arranged in parallelism with said elongated support and spaced equi-distantly therefrom. at. opposite sides of said frame, said cylinder and piston devices having foot pieces thereon below said frame and engageable with the floor. a liquid. pump carried by said frame intermediate. said devices and in adjacency tov the: lower end of said support, and valve controlled passage means in said frame between the cylinders: of said devices and having connection with said pump between said cylinders for supplying liquid under pressure concurrently to said devices to extend the latter to bring said foot pieces'firmly into engagement with the floor even when the latter is. uneven.

16-. In a supporting column, in combination, a; lower frame, an elongated upright supportase cured to said frame midway between the sides of the latter and having a roof engaging member at its upper end, a pair of extensiblehydraulic cylinder and piston devices secured to said frame and arranged in parallelism with said elongated support and spaced equi-distantly therefrom at opposite sides of said frame with the upper ends of said devices extending upwardly relative to the lower end of said support and with the lower ends of said devices near. the bottom of raid frame, said cylinder and piston devices having foot pieces thereon below said frame and engageable with the floor, a liquid soa carried by said frame intermediate said devices and in adjacency to the lower end of said support, and valve controlled passage means in said frame between the cylinders of said devices and having connections with said pump between said cylinders for supplying liquid under pressure concurrently to said devices to extend the latter to bring said foot pieces firmly into engagement with the floor even when the latter is uneven.

17. In a hydraulic mine column, a pair of parallel extensible cylinder and piston devices respectively having floor engaging abutments, a cross connecting frame extending between and secured to said devices, a column element supported by said cross frame midway between said parallel devices and extending vertically above said cross frame, said column element having a roof engaging abutment, a source of liquid under pressure on said cross frame, passages in said cross frame for connecting said liquid source to the cylinders of said devices, and means on said cross frame for effecting liquid flow from said source through said passages to the cylinders of said devices whereby the pistons of said devices may be concurrently subjected to the action of hydraulic pressure to extend said devices to bring about, with the column element vertical, firm engagement of said floor engaging abutment with the floor, whether the latter is level, uneven or sloping, and also'firm engagement of said roof engaging abutment with the roof, whereby said column may be fixed in vertical position, and said liquid flow effecting means embodying means operative to effect trappin of liquid in the cylinders of said devices'to hold the latter firmly in adjusted position thereby to secure the column in place between the roof and floor.

1 18. In a hydraulic mine column, a centrally located vertical column element having a roof en,- gaging abutment and a base providing a cross frame, a pair of extensible cylinder and piston devices arranged in parallelism on said base at the opposite sides of said cross frame and spaced equidistantly from said centrally located column element, said devices respectively having floor engaging abutments, a source of liquid under pressure on said base, passages in said cross frame for connecting said liquid source to the cylinders of said devices, and means for effecting flow of liquid under pressure from said source through said passages to the cylinders of said devices for concurrently subjecting the pistons of said devices to the action of hydraulic pressure to extend said devices to bring about, with the column element vertical, firm engagement of said floor engaging abutments with the floor, whether the latter is level, uneven or sloping, and also firm engagement of said roof engaging abutment with the roof, whereby said column may be fixed in vertical position, and said liquid flow effecting means embodying means operative 'to effect trapping of liquid in the cylinders of said devices.

12 to hold the latter firmly in adjusted position thereby to secure the column in place between the roof and floor.

19. In an extensible hydraulic supporting'column, a bottom frame having a transverse portion, a vertical column element secured centrally to said transverse frame portion and extending upwardly and provided at its upper end with a roof engaging abutment, a pair of cylinder and piston devices carried at the sides of said transverse frame portion and arranged in parallel relation and spaced equidistantly from said column element, said devices having floor engaging abutments at their lower ends, a liquid reservoir carried by said bottom frame, a pump on said bottom frame, passages in said transverse frame portion for connecting said pump to said reservoir and to the cylinders of said devices, and means for effecting flow of liquid from said pump through said passages to the cylinders of said devices concurrently to extend the latter to bring about,'with the column element vertical, firm engagement of said floor engaging abutments with' the'floor, whether the latter is level, uneven or sloping, and also firm engagement of said roof engaging abutment with the roof, whereby said column may be fixed in vertical position, and said flow effecting means being operative to effect trapping of liquid in the cylinders to hold firmly said devices in adjusted position thereby to secure the column in place between the roof and floor.

JOHN C. CURTIS.

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