US3295814A - Control means of mine roof supports - Google Patents

Control means of mine roof supports Download PDF

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Publication number
US3295814A
US3295814A US425123A US42512365A US3295814A US 3295814 A US3295814 A US 3295814A US 425123 A US425123 A US 425123A US 42512365 A US42512365 A US 42512365A US 3295814 A US3295814 A US 3295814A
Authority
US
United States
Prior art keywords
ram
cylinder
piston
pressure
prop
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US425123A
Other languages
English (en)
Inventor
Town Frank
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
WE&F Dobson Ltd
Original Assignee
Dobson Ltd W E & F
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Dobson Ltd W E & F filed Critical Dobson Ltd W E & F
Application granted granted Critical
Publication of US3295814A publication Critical patent/US3295814A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D15/00—Props; Chocks, e.g. made of flexible containers filled with backfilling material
    • E21D15/50—Component parts or details of props
    • E21D15/51—Component parts or details of props specially adapted to hydraulic, pneumatic, or hydraulic-pneumatic props, e.g. arrangements of relief valves
    • E21D15/512—Arrangement of valves
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D15/00—Props; Chocks, e.g. made of flexible containers filled with backfilling material
    • E21D15/14—Telescopic props
    • E21D15/44—Hydraulic, pneumatic, or hydraulic-pneumatic props
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D15/00—Props; Chocks, e.g. made of flexible containers filled with backfilling material
    • E21D15/60—Devices for withdrawing props or chocks
    • E21D15/606—Devices for withdrawing props or chocks the props being moved systematically
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D23/00—Mine roof supports for step- by- step movement, e.g. in combination with provisions for shifting of conveyors, mining machines, or guides therefor
    • E21D23/16—Hydraulic or pneumatic features, e.g. circuits, arrangement or adaptation of valves, setting or retracting devices
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D23/00—Mine roof supports for step- by- step movement, e.g. in combination with provisions for shifting of conveyors, mining machines, or guides therefor
    • E21D23/16—Hydraulic or pneumatic features, e.g. circuits, arrangement or adaptation of valves, setting or retracting devices
    • E21D23/18—Hydraulic or pneumatic features, e.g. circuits, arrangement or adaptation of valves, setting or retracting devices of advancing mechanisms
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D23/00—Mine roof supports for step- by- step movement, e.g. in combination with provisions for shifting of conveyors, mining machines, or guides therefor
    • E21D23/16—Hydraulic or pneumatic features, e.g. circuits, arrangement or adaptation of valves, setting or retracting devices
    • E21D23/26—Hydraulic or pneumatic control

Definitions

  • An object of the invention is to provide for operation of the switch in such improved manner that it will be operated only when the prop is actually supporting the roof.
  • the invention provides a hydraulic prop having a control device for controlling another hydraulic device, an operating device movably mounted at an end of the prop for operating the control device, and means whereby relative movement between the operating device and said end of the prop to operate the control device is eflected only when a predetermined pressure is exerted by the prop against the roof.
  • the prop has an operating cap slidable on the outer end of the ram and adapted for operating the control device consequent upon relative sliding movement between the cap and the ram, and wherein the ram, its pressure cylinder, and the cap form a diiferential piston and cylinder arrangement whereby prop-extending pressures below a predetermined pressure act in the cap to prevent said relative movement and a predetermined prop-setting pressure in the pressure cylinder overcomes the pressure in the cap to effect said relative movement and the control device is consequently operated.
  • the operating cap is biased in projecting direction by spring means and the mode termined prop pressure is sufficient to overcome the force of this spring in addition to the fluid pressure in the cap before the control device is operated.
  • the control device may be an electric switch, or a hydraulic pilot valve and it may be operable by the operating device through the intermediary of a cam slide movable by the operating device.
  • the con trol device is operable through a plunger and a cam slide mounted in the ram, and the cam slide is operable by a spigot carried by the operating device.
  • the upper end of the ram is in the form of a piston, the operating device is an end cap forming a cylinder for the rams upper piston, and this cylinder and ram is of less diameter than that of the rams lower piston and its pressure cylinder.
  • the ram has a central bore communicating between a fluid connection and an annulus between the ram and its cylinder, a pipe is mounted in the bore to connect a second fluid connection to the rams cylinder, and the cam slide is mounted in the bore above the inlet and is formed with fluid ducts: connecting the inlet to the upper cam cylinder.
  • the invention also provides a hydraulic prop comprising a ram and pressure cylinder therefor, first and second fluid connections communicating with an annulus etween the ram and its cylinder and with the rams cylinder respectively, a control switch mounted on the ram with an operating plunger directed to a central bore in the ram which communicates with the second fluid connection, a cam slide in said bore engaging said plunger and formed with ducts for fluid from said second fluid connection, a piston formed on the top end of the ram and through which the cam slide is directed, a top end cap on the ram and forming a cylinder for the rams top piston, a spring in the cap biasing it upwardly, and a spigot directed downwardly from the cap and engaging the upper end of the cam slide.
  • FIGURE 1 is a sectional view of a hydraulic prop according to the invention.
  • FIGURE 2 is a side view thereof.
  • FIGURE 3 is a sectional view of a part of the hydraulic prop shown in FIG. 1 according to an. alternative embodiment of the invention.
  • the hydraulic prop is in this instance one of two similar hydraulic props which are interconnected by a horizontal advancing cylinder and ram providing a step by step advancing roof support of which there is a series employed along a coal face.
  • the necessary operations of extending and contracting the digerent props and in advancing the different props in a required cycle of operations is desirably achieved automatically by each operation being accompanied by operation of an electric switch to instigate the next operation and so on.
  • each is provided with an electric switch as indicated at 1 in FIGURE 1.
  • the prop is in this instance of the type comprising a cylinder 2 forming a pressure chamber 3 in which operates a piston 4 on a ram 5.
  • a pipe 6 extends through the ram 5' from a lower location where it communicates with the pressure chamber 3 and an upper location where it communicates with a chamber 7 at the position of a fluid connection 8 to which there can be alternatively fitted a suitable fluid charging unit connected to a pressure fluid supply or a return line.
  • a second fluid connection for a return line or a charging unit is indicated at 9 in FIGURE 2 and this is in communication with a chamber 10 which is itself a communication, via a bore 11 in the ram 5 and a transverse duct 12 with the annulus 13 between the ram 5 and the cylinder 2.
  • a plunger 1.4 which is operable, through a ball 15 by a cam slide 16 disposed in the chamber 7 and having a cam face 17 engaging the ball 15.
  • This cam slide 16 has sealing rings 18, 19 for sealing against the fluid in the chamber 7, and the upper end of the cam slide 16 projects through a chamber 20 which houses a biasing spring 21 for biasing the cam slide 16 in an upward direction.
  • the upper end of the ram 5 is in the form of a piston 22 which is of less diameter than that of the piston 4.
  • an end cap slide 23 which at its lower end forms a cylinder 24 for the piston 22, there being a pressure chamber 25 between the end slide 23 and the piston 22, this chamber 25 being in communication with the pressure chamber 3 through the pipe 6, the chamber 7, and a duct 26 in the cam slide 16 and connecting the chamber 7 with the chamber 29 which is open to the pressure chamber 25.
  • the end slide 23 has a central spigot 27 for engaging the cam slide 6 and mounted on this spigot there is a thrust member 28 which is biased downwardly by resilient means 29 which in the illustration consists of Belvedere washers, but which may consist of a spring or of a rubber block or the like.
  • the end slide 23 is normally biased in extending direction from the ram 5 by the resilient means 29 acting between the end slide 23 and the thrust member 28 which bears on the piston 22.
  • the switch 1 is of course suitably associated with the mechanism next to be operated and operates, for example, a solenoid operated control valve for controlling the operation of a successive hydraulic prop in the manner hereinbefore described of a further section of a hydraulic sequence.
  • the switch 1 is not only prevented from operation when the prop engages the roof without actually supporting the roof but it is also prevented from operation if the roof happens to be so high that the prop in its fully extended condition does not reach the roof. In other words the switch 1 cannot be operated to instigate the next operation under any circumstances other than when the prop is actually supporting the roof.
  • a hydraulic pilot valve 30 which, as seen in FIG. 3, will operate a hydraulically-operated control valve for controlling the operation of a successive hydraulic prop or a further section of a hydraulic sequence.
  • a valve member 32 is hydraulically actuated through inlet 34 and outlet 36 against a return spring 38 to be actuated by plunger 14 to operate the props in the manner of switch 1 in the previous embodiment.
  • a cylinder and ram assembly comprising a ram, a ram piston thereon, a ram cylinder in which the ram piston is slidable, an inlet for leading pressure fluid into said ram cylinder, a control device mounted on said ram and operable for instigating a separate operation other than that of the cylinder and ram assembly, operating means including an end member axially slidable on said ram so as to operate said control device upon relative contraction between said end member and said ram, and pressure applying means providing a predetermined pressure less than the loading pressure of the ram piston and ram cylinder and disposed in separating association with said end member and said ram, whereby said ram piston and ram cylinder must be pressure loaded in excess of said predetermined pressure before said control device is operated.
  • a hydraulic prop comprising (a) a cylinder
  • a hydraulic prop according to claim 2, wherein the operating device comprises an operating member slidable in said ram under control of the hydraulic fluid in the prop, said member engaging a spigot biased against said end member, said end member being slidable on the outer end of said ram and forming an auxiliary piston and cylinder in operative association with said operating device.
  • a hydraulic prop according to claim 2 wherein said end member forms a cap axially slidable on the outer end of said ram forming an auxiliary piston and cylinder, a fluid duct communicating between said ram cylinder and said auxiliary cylinder.
  • a hydraulic prop according to claim 2 wherein the end member and the outer end of said ram comprise an auxiliary piston and cylinder forming an auxiliary pressure chamber therebetween, the cross-sectional area of said auxiliary piston and chamber being less than that of the main piston and pressure chamber, whereby the control device is operated only upon a predetermined load being applied to the prop.
  • a hydraulic prop according to claim 2, wherein the operating device comprises an operating member slidable in said ram under control of the hydraulic fluid in the prop, said member engaging a spigot biased against said end member, said end member being slidable on the outer end of said ram and forming an auxiliary piston and cylinder in operative association with said operating device.
  • the operating means includes an operating member slidable in said ram under cotnrol of the hydraulic fluid in the prop, said member engaging a spigot biased against said end member, said end member being slidable on the outer end of said ram and forming an auxiliary piston and cylinder in operative association with said operating device, the cross sectional area of said auxiliary piston and chamber being less than that of the main piston and pressure chamber, whereby the control device is operated only upon a predetermined load being applied to the prop.
  • a hydraulic prop according to claim 2 wherein said end member forms a cap axially slidable on the outer end of said ram forming an auxiliary piston and cylinder, a fluid duct communicating between said ram cylinder and said auxiliary cylinder, the cross sectional area of said auxiliary piston and chamber being less than that of the main piston and pressure chamber, whereby the control device is operated only upon a predetermined load being applied to the prop.
  • the operating device comprises an operating member slidable in said ram under control of the hydraulic fluid in the prop, said member engaging a spigot biased against said end member, said end member being slidable on the outer end of said ram and forming an auxiliary piston and cylinder in operative association with said operating device and having a fluid duct communicating between said ram cylinder and said auxiliary cylinder, the cross sectional area of said auxiliary piston and chamber being less than that of the main piston and pressure chamber, whereby the control device is operated only upon a predetermined load being applied to the prop.
  • control device is an electric switch.
  • a hydraulic prop according to claim 2, wherein said control device is a hydraulically operated pilot valve.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mining & Mineral Resources (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Geology (AREA)
  • Mechanical Engineering (AREA)
  • Structural Engineering (AREA)
  • Actuator (AREA)
  • Fluid-Pressure Circuits (AREA)
  • Fluid-Driven Valves (AREA)
  • Press Drives And Press Lines (AREA)
US425123A 1964-01-18 1965-01-13 Control means of mine roof supports Expired - Lifetime US3295814A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB2314/64A GB1086002A (en) 1964-01-18 1964-01-18 An improved hydraulic prop

Publications (1)

Publication Number Publication Date
US3295814A true US3295814A (en) 1967-01-03

Family

ID=9737370

Family Applications (1)

Application Number Title Priority Date Filing Date
US425123A Expired - Lifetime US3295814A (en) 1964-01-18 1965-01-13 Control means of mine roof supports

Country Status (5)

Country Link
US (1) US3295814A (xx)
BE (1) BE658328A (xx)
DE (1) DE1226513B (xx)
FR (1) FR1421076A (xx)
GB (1) GB1086002A (xx)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103291335A (zh) * 2013-05-31 2013-09-11 巨隆集团芜湖兴隆液压有限公司 一种平衡浮动双向锁

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4621565A (en) * 1984-08-15 1986-11-11 Automotive Products Plc Hydraulic slave cylinder switch
CN110259491B (zh) * 2019-07-04 2024-06-11 山东中煤电器有限公司 液压支架用电动直推式换向阀

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1069549B (xx) * 1959-11-26

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
None *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103291335A (zh) * 2013-05-31 2013-09-11 巨隆集团芜湖兴隆液压有限公司 一种平衡浮动双向锁

Also Published As

Publication number Publication date
DE1226513B (de) 1966-10-13
GB1086002A (en) 1967-10-04
BE658328A (xx) 1965-04-30
FR1421076A (fr) 1965-12-10

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