US1857624A - Percussion tool for wave transmission apparatus - Google Patents

Description

i ,1932. w. R. DEGENHARDT ET AL 1,857,624

PERCUSSION TOOL FOR WAVE TRANSMISSION APPARATUS Filed Feb. 28, 1928 Will " 90 percussion tool Patented May 10, 1932 UNITED STATES i WILLIAM. RUS EL DEGENPIARDT, or LONDON, A LAN FRED DE ERAINE; F WEMB'LEY, AND ROBERT HENRY BICKNELL, DECEASED, LATE OF WESTMINSTER, ENG AND, BY ROBERT ALA WIMBERLEY BIoKNELL, 0E .LoNDON; AND ARTHUR BIcKNELL, 0F BIRMINGHAIvL-ENGLAND, LEGAL REPRESENTATIVES 'oE ROBE T HENRY BICK- NELL, DECEASED, ASSIGNORS To THE ERANooIS oEMENT TIo GOM AN LIMITED, 013 EoNoAsTER, ENGLAND, A BRITISH COMPA 4 Y I I PERcUSsIoN TooL PoR wAvE' TRANSMIssIoN APPARATUS This invention relates to percussion tools 7 for operation by compressional liquid wave transmission mechanism and. more particularly to the spring suspension of the tool by the aid of a body ofliquid,the compressibility of which under the rapid wave transmission gives the necessary resiliency for the suspension. 1 In the suspension of tools of this kind it is 11) necessary to obtain resonance between the reciprocating mass and the resilient element. As is Well-known, in any spring suspension of a mass, if any predetermined natural I period of oscillation is to be obtained, the re- 16 siliency or capacity of the spring suspension must bear a definite relation to the reciproeating mass which is supported and the greater the mass the more rigid must be the resilient support. For substantial masses and high 80 periodicity of oscillation the yield of the spring suspension for a given force must be small and the compressibility of a. volume of liquid is sufiicient, in the case of aconsiderable reciprocating mass, to bring the natural period of the suspension sufficiently low to correspond to the periodicity of the wave transmission, so that resonance is established forfthis periodicity.

The use of li uid as a resilient body in a the liquid being divided into two volumes on opposite sides of a dividing wall belonging to the body of the tool, but according to the which-resonance depends is composed of a single body or column of liquid. Through this body or column of liquid extends the percussion orstriking device or rod and according to a further feature of the invention this rod is not directly acted upon by the wave transmission, but an intermediate striking member is provided on which the wave transmission liquid operates. .This intermediate member, which is preferably in the form of a sleevemounted on the percussion rod, meets towards the end of itsstroke a collar or projection on the rod and delivers the blow to the rod and thence to any percussion device which it is designed to operate; A portion of the said sleeve is disposed within a chamber conas already been proposed, 7 in front of the working chamber (1;; I

present inventionthe resilient element on Application filed February 28, 1928, Serial'No. 257,768, and in Great Britain Mar-ch25, 1927. I I

taining the aforesaid single body or column of liquid and is so form'edthat after a forward stroke has been"given,-i the sleeve is forcedback on the return wave against the operating wave-transmission liquid J by the pressure in the said chamber, ready for the next forward stroke. i c l In order that thesaid invention may be clearly understood and readily carried into effect, the same will now be more fully described with referencetothe accompanying drawings in wh1ch:-; V

Figure 1 is an 'axlal section of one form of percussion tool constructed'according to this 1 invention, and. l

Figure 2 is an ax ial section of another form. of percussion tool constructed according to this invention. w q

In both of the constructions shown A is the body or casing of the tool, B is the percussion rod which is arranged centrally within' the body A-and passes through glands A A at the rear andforward ends of the tool body,

C'is the workingchamberlto whichthe'opel I ating wave-transmission liquid is admitted by means ofa pipe C and -D isthe aforesaid chamber containingthe single body of liquid (hereintermed-':the liquid spring Chamber) situated inthe forward part of the tool'body Referring to Figurel Eis the" aforesaid intermediate striking member inthe form of asleeve surrounding the percussion rod B. This sleeve passes through a bushing E of substantial length at the middle portion of the tool,in which bushingvit has a close. sliding fit, the'sleevealso having a close sliding fitup'on'the percussion rod B; Thefor- Ward end of'the sleeve E. is providedwith a head E forming at'the rear a shoulder the surface of'which'isof smaller area than the forward end of the headyowing to the thickness'of the sleeve ,itself,; so that the head forms a differential" piston and the pressure in the liquidspring chamber Din which the head is situated tends to drive back the sleeve.

The rearend of'the sleeve is openpto the Working chamberC to which the wave-transmission liquid'is supplied so thattheWave motion transmitted through the: liquid acts upon the rear end of the sleeve E and during the forward half of the wave this. sleeve is forcedforward at high velocity, increasing from the beginning of the Wave and compressing, the liquid inthe spring. chamber.

'.At about the point of. maximum velocity the head of the sleeve strikes a thick collar B on.

the percussion rod and the blow is delivered to ya percussion portion of the tool suitable for any desired type of operation such. as percussion drilling. Following upon the delivery of the blow the compressed liquid in the liquid spring chamber D begins to return the: sleeve Evv and duringthe succeeding half wave,' when the pressure of the wavetransmission liquid falls to its minimum,' the sleeve returns to its initial position ready for the next stroke, which begins when: the compression ha'l'tt of the wave starts. The forward movements of the rod 13' are limited by the collarB 'whiclm comes against the rear end of a bushing A ein which the front part 7 of the said rod slides, and the rearward movements ofthe sleeve E- are limited by its head E whi ch'comes against the front end of the atoresaid bushing p I As the sleeve E must be free to slide readily over the contacting surfaces and there are during eachoscil'lation considerable differences of pressure betweenthe liquid spring chamber D and the working chamber C recei'vingthe operating wave-transmission liquid, leakage is liable to occur froirn'the work ing chamber intothe liquid spring chamber and to prevent an undesirable accumulation of pressure in the latter chamber 'we may provide as shown a relief valve F which opens; at a predetermined pressure. The said relief valve F would beset to open at about the mean pressure in the working chamber C. This relief valve forms the subject of our Uru' ted States Patent No. 1,771,672, British Patent application No. 8,281 of 1927,. now Patent No. 293i,088,-a':nd may beE-replaced by any of the equivalent devices mentioned in the specification of that application. ,The s r spring controlled relief valve 6 similar to the relief valve F. A screw-down valve G may also be provided for controllingthe flow otliquid from the working chamber C to the liquid spring chamber D through a passage A in the tool body. This valve is opened when the tool is to be started work-- ing so as to enable the'chamber D to be filled with liquid is closed during normal working; it can, howeverjbe partly opened to any desired extent during working, so as to vary the force of the blow of the sleeve E upon the collar B oftl ie percussion rod B. V

With a single resilient body of liquidiin the chamber D and an intermediate striker or sleeve E as above described, there is relative- 1y small wear upon-the packings of the permission rod B as its -movement'is. confined tic-u of t roundin said rod withrelative lon itudinal 3 63 may be provided, as showmvvith a to the small movement of the blow, while the relatively large reciprocating movement given by the wave-transmission is taken up by the said sleeve which has'a long bearing surface and does not require packing as both ends of the sleeve .areiin liquid;

The construction shown by Figure 2 is similar to that shown by Figure 1 except for the omission of the sleeve E and the consequent alteration in the percussion rod B, similar parts being indicated 'by the same reference letters, in the two figures. As a result of the omission of the sleeve Ethe middle portion B of therod- Bthatis situated in the bushing E is made of larger diameter t'l ian the rear portionof therod to provide an area for cheep-erecting liquid in e the working chamber C tov act upon the required area for the liquid in the chamber D to act upon in orderto. move the rod rearward-s is provided by making front porhe rod: of smaller diameter than the middle portion as shown. A collar B lS13'1 0. vided' for limiting the rearward movements of the rod B, andthetorward movements areni limited: by the sheuld erfbetween the: larger (dd'SJILGU-XFPQItlOB and the smaller diameter front portion of the rod, saidcollarand shoulder comi'n 'against the bushings and A respectively. \Vhat we claim and, desire to secure-by Lettors: Patent of the United States is-:-"

In a percussion tool tor operation by compressional liquid wave-transm mechanism,,the combination with apercussio i3 rod and a working chamber of a sleeve su-rmovement them, 0 e end of s d sleeve being in contact with 4 liquid chamber, and a chamber containing a s g body of liquid. in which the other end of saie sleeve is disposed, said sleeve being sov constructed that after a forward stroke hjasbeen performed it is moved back by the pr of the liquid in the secondmentioned her ready for the next forward stroke 2. In a percussion tool for operat compressional liquid wave-tra sr i-neehan-ism' the combination with. i, A we ments claimedin claim 1, of relief valve for 31 ,th single body of-liquid. 1 "3. In a percussion tool for openationby compressional liquid waveeri n mechan sm, the combination with moi claimed in claim Lot a-conve tween the working chamber and the chain ber ontaining the single of liquid an clj-,11-stable: valve controlling this con-fl WILLIAM RUSSELL'DEGENHA'RDT.

AL-LAN FREDA: FRA HE- ROBERT ALAN. WIMBERLEY'BICKNELL; ARTHUR mcxum, V Administrators for Robert H emry BicilmeZL- Deceased.

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