| 摘要 |
<p>693,038. Pit props. GEWERKSCHAFT EISENHUTTE WESTFALIA. March 31, 1950 [April 7, 1949; Oct. 24, 1949], No. 8196/50. Class 20(ii) [Also in Groups XXVIII and XXX] A hydraulic pit prop has a charging and discharging valve 23, Fig. 3, and an excess pressure valve 24, charging being effected through a hose 15 terminating in a connecting member 30 in the form of a lever which is coupled by means of a hook 31 to a handle 26 on the prop, so that pressure on the long tubular lever arm 32 forces the short arm end 35 and pressure pin 34 against the inlet opening of the valve 23 thereby conveying water through the arm 32 and outlet tube 33 into the prop without any screwing action being necessary. Discharge is effected simultaneously with the knocking down of the prop by means of a chain 51, Fig 4, linked to a lever 46 hooked on to the handle 26 and carrying a pressure pin 49 which, on pulling the chain, opens the valve 23. The valve 23, Fig. 3, comprises a sprung ball 27 closing the inlet which has externally a conically flared surface adapted to make a sealing fit with the short lever arm packing cone 35 surrounding the outlet tube 33 which terminates in the pressure pin 34. The connecting member 30 also contains a supply valve 37 which is opened by a striker pin 40 upon moving a handle grip 38 in the direction of the arrow 39. The length of the pin 34 is such that on setting a prop which requires to be shortened, a slight depression of the lever arm 32 causes the pin 34 to open the valve 23 before the packing cone 35 comes to rest on the flared inlet, thus releasing water from the prop. After positioning of the prop, further depression of the arm 32 and operation of the supply valve 37 then causes water to enter the prop when the connecting member 30 is unhooked and used for setting up another prop. Damage to the prop is prevented by the relief valve 24, the valve body 43 of which under the loading of a spring 44, closes a small opening 45 on the outside, the spring 44 being loaded to the maximum load of the prop. In a roof support system, Fig. 1, (not shown), the props 14 are arranged in "saw-tooth" formation and are set up in sequence by connecting them by means of the pressure hose 15 to coupling points 17 on piping 16 extending alongside the conveyer 12 and supplied by an electrically or compressed air operated pump 18.</p> |
