5 trol as hereinaiter described. The hammer carryin- vebicle may &@erefore bo selectively driven either in a conventional manner for over-the-road travel by mechanical means or by hydraulic power for creeper or slow speed travel during hammer c-peration. FIG-LJRE 8 schematicaily illustrates the hydraulic system employed on the r@iachine 2 for conlrolling oi)eration of the impact tool, tilting of the mast aid attendant structure, and ci-eeper or slow speed hydraulic operation of the vehicle. This system includes a main hvaraulic control 214 wh-ich is located in a posi!ion co:ivenient to the oi)erator and which provides for both manual and ail-tomatic o-o.-ra'Lion. As shown, hydraulic fluid is supplied from a rcservoir 209 through a pair of i'ilters 20@l., 206 located i@ti the discharge lines from the r,-servoir. The o-atiet or discharge liie from the hydraulic reservoir 200 is connected to a tandem -@ydrau!;C pump 208, 210 (through filters 204, 206.) for supplyin@ operating fluid thereto. The hydraulic pump 208, which is preferably of greater capacity than th-. pump 210, is employed for raising the imp,,ict tool 20, the lift of @Ahich is controlled by the cylirder ar@d piston 28. The hydraulic pump 210, is, in ttir!-i, e imployed to operate the hydraulic motor 44 for driving the carriage alona the transvers-, support 14, for operatin.- the hydrailic cylinders 38 and 40 to tilt the mast and its attendant sLnetLre both sidew;se and foreand-aft, and for supplyin.a pressurized -fluid to operate the creepor motor !I 68. As previously indicated, 'Lhe irnpact forces of the worki)iece 24 are d@@t)endent upo:i the fre-, f,-Il height of the bammer, and it is proposed herein to control this free fall hei@-ht by a timer 220 vihich acc@irately cotitrols th@- flov,, of pressurizcd oi)erating fluid to the lifl cylitider 28. The automatic ti-Tner 220 is likewise located conveniently to t'.e veh@cle operator and when set, this timer operates a r,ilot operated clieck valve 218, as throu.-h the solenoid valve 222, to regi.,,Iarly and at predetermined timed intervals conduct fliid under pressure to the upper end of t@ie cylir.,d,-r 28 to thereby I;ft the hammer and impact tool to a predetermned and regulated dro-o hei,-ht and to subsequently '@nter@-upt fluid pressure flow at such regul-,It-,d hei,@hts. As a safely measure in order to provide i)rotcction a.@ainst overpressurizing of the hydraulic s@,stem-, a relief valve 233 is interposed in the hydraulic lir.e between the control valve 214 and the hydraiilic pu,n-) 208. An accumulator 215 and rel:ief valve 216 are prele,- ably inierposed in the line between va'ive 2'@14 and cyl,,-ider 23 in order to relieve sudden fli,-ctuations in t)ressi.ire dlie to pulsations in the system in normal and abnormal operatioti. Thus, the control 214 provides for raise, drop and hold positiois of the hydraulic cylinder 23 togctl-,er vvith the weigh,led tool actuated by sitch cylinder, a,id the automat;c timer 220, a-s set bv the operator, is operable to regulate fluid pressure flow automatically ,,.nd at regularly timed i-it rvai 's to the lift cylinder 28 for lifti I na the bammer and impacting tool to pred-@terini,-ied droo beiahts wben the control 214 is in raise position. The operat:on of the hydraulic creeper motor 168 fro-rn fluid pressure created by the pump 210 is controlled by means of a control valve 224. As above described, the hydraulic motor 168 is connectable to the power train for driving the vehicle upon disengagement of the conventional vehicle drive from the usual power source by means of the cILitch 153, and th;s hydraulic creeper r@iotor is adapted to propel the macb',,n-. 2 at speeds much slower than those which inay b,- obtained (with conventional means) ilrom the i-notor 6. The creeper drve riiay thus be utilized to advantage Nvhen operatin- the impact mechanism of the machine so that the tool and its carriage traverse the transverse support 14 as the veh is either slo@vly or interinittently moving ',.n a forward arward dir@-ction as deterniiii@-d by the operator, and this featare is particula:,Iy useful in pavement breaking operations and the like whorein it is desired to work upon relatively wide successive sections of roadway. 37365,005 6 A control 226 may also be provided in the output line of the pump 210 for the purpose of controllin.- operation of the hydraulic motor 44 which is mounted on the carriage 16. When fluid under pressure is conducted from P, the pump 210 to the motor 44 as controlled by the operator, ' e carriage and the associated -Uides or mast 13 alrn- with the hammerin- tool 20 are driven by the irotor aloii.- the support member 14 transversely of the veh;cie. In addi@Lion, a control 22o' may similarly be provided for controlling flow of fluid under pressure from the 10 plnp 210 to the hydraulic cylinder 38 which is employed for sidewise t;lting of the masl and -.uides 18 "hereof along with the hamr@ier tool 20. Additionally, a control 230 may be provided for controll;ng flllid flow from the p,,im@n 210 to the hydraul;c cylinder 40 utilized forpositionin.- the guides IS and mast in fore-and-aft or upri.-ht a-@id layback positions. The return lines from valves 214, 216, 213, 230 to the reservoir 200 are preferably provided with a suitable oil 20 cooler 232 in a con-ventional manner. Var;ous rnodes of carrying out the invention are contemplated as being within the scope of the following claims particularly pointing out and distinctly clairning the siibject matter which is regarded as the invention. 25 Nve claim - 1. A mobile impacting machine comprising: a power-driven wheeled chassis; a rne atis on said chassis providing a pivotal mounting at or.,e end thereof; a sup port member carried by said pivotal mounting and formed wilh a pair of laterally spaced tracks disp osed in parallel relation to the pivot axis; one of said tracks having a pair of s.t)aced Ranges and th-. other of said tracks having a single 35 flan ge; a carr ia,-e having sets of laterally spaced rollers engaged with said tracks to permit mov@-ment of said carria,@e therealon.- in a path extending transversely of said chass-@s; 40 one set of said rollers including at leasl one roller 45 peripherally enga.-ed with one of the spaced flanges of said first mentioned track aiid at least one other roller engaged with the other flange of said first rfientioned track, and the other set of said rollers including at least one roll-- r p@-rip rally en.-aged with one side of the flange of said second mentioned track and at least one other roller enga,-ed with the other side of the flan.-e of said first mentioned track; gilide means motinted on said carriage for movemeiit therewith alorig said tracks; an impaeting tool carried by said guide means for reciprocati-ng movement ther,-along; and means connected with said impacti-@ig tool for raising the same to predeterinined drop heights. 55 2. A mobile impacting machiric acco.-din- to claim 1, wh--rein the rear track is angularly inclined relative to the front ' rack. 3. A mobile impactin.@ macbine according to claim 1, wherei-.1 the rollers which are en.aaged with the upper (io flange of the froit track are adjlistably mounted for movement toward o,-@id away from the lower flange of said fronttrack. 4. A mobile impacting machine accordin@- to claim 1, wh-,rein the rollers peripherally engaged with the lower (i,,-) fladge of the front track include at least one roller on one side of said track and at least one other roller on the opposite side of said track. 5. A mobile impacting machLTie comprisin@: a power-driven wheeled chassis; 70 means on said chassis providing a pivotal mounting at o@ie etid thereof a support memblr carried by said pivotal mounting and forrned with a pair of laterally spaced tracks and a-@l intermediate rack aH disposed in parallel relation 75 to the pivot taxis;

3,365,005 7 said rack havin- te,-+h exictiding from one side thereol' and a plain ,-aide surface on the opposite side thereof; a carriage havin.- ro'@lers engaged iv@@th each o" said tracl@:s to permit movement of said carria-e therealon.@ in a path extc@idin.- traisversely of said chassis; said carriaae also havip@- a gear driv-ingly enga-ed will the ieeth of sa;.d rack atid a rol'ier periphera@,ly coactin.- wilh the -olain gliide su@rf-ace thereof; means m-,u@7,t@d oii said carria.-e fbr said @-ear to move said carria,-e alon.- said tracks; gu;de means mo-cn,'cd o-i said carria,@e for moveme-Tit therewith; an irrpactiii.- tool carred by said guide means j'or reciprocating movement therealon.@; and means con@--@eted -,vith said imnactin@ tool for raising the same to pr,-,deLer-inined drop heights. 6. A mobile iinpacling machine accordi-@l- to claim 5, wherein the gear which drivi,@i,@jy c-,lga.-es the rack is carried by a sbaft v.,hich is loosely mounled to provide a iloa+ing suppbrt for sa;d gear. 7. A mobil@e impactiiig machine accordin- to claim 5, wherein th-- gear which drivin,@ly enga.-es the rack is dr;,ven by a '.iydraiilic motor throu@.-h a @ear mounted on the motor shaft, thp. driven -ear b-.ing carried by a shaft which is loosely mounted on the carriage to permit said driven gear to fioat to a limited extent. S. A @-nc-bile impactin.- machide according to claim 1, @v@iereiii a hydraulic cylinder is mounted on the r.,last and has an exte-@idable p,@'ston co@ii-ieced with the i@npacting too!, the cyli.,ider being connected with a so,-rce of pressuri-7ed operafin.- fiu,.d, a ti.-iier be;ng provided for controll'n-, the fiow of pressurized operating fluid to actuate the ' ool. 9. A mobil-@ imr)acti-iig machine according to claim 1, -wl-@e,-ein hyd@- au'tically operabl-- rneans is connected betl;icen 'he chassis and the support member -for swip-ging 'che sa-pport member a@id the guide means carried thereby from a si-ibstan,ially vertical posi'@ion +lo asubsta-ntially horizodtal position overlyin.- the chassis. 10. A mobi@e impacting machine accordi-@ig to claim 1, vihere-"n qrst and secor@d povv.-r 'cransmission means are orovided togeth.-r with means or selectively couplirig and un-loupl;pl- said first and se--Ond --oower transmission -iiiear@s wilt-i the wheels of Lhe chass;s to thereby d@-ive the wlicels a-d transnort the chassis at normal and abnormal ra'Les of speed respectively. References Cited UNITED STAT-PS PATENTS 2,069,138 1/1937 Feeliey --------------- 74-27 2,732,197 1/1956 Cor,-ett ----------- 173-43 X 2,-oO5,847 9/1957 Malloy ------------- 173-22 2,832,567 411958 Fletcher et a! - ------ 308-6 X 3,088,385 5/1963 Dorkins et al. ---- 173-28 -@ 3,172,483 3/1965 Spitzer ----------- 173-28 X FRED C. MATTER'PL JR., Priii2,,ziy E,@am;l@ei-. P. XESSLER, Assista.-il E@,-an,,iiier.

Uni'ted States Patent Office 3,365@005 3,365,005 MOBF-E EvIPACTliNG MACvR7.NE Chnrles W. Berkobein, Troy, 2nd f,Loyce J. j-tlz!chiHison, S;dr4ey, Oh-lo, and Arthur J. Bent, Geneva, lil., assignors to V@estiiighouse Air BrA-e Company, Wiliuerding, 5 Pa., a corporation of Penasylvaula FRed Oct. 5, 1965, Ser. No. 493,093 10 Claims. (Ci. 173-43) 1 0 ABST RACT OF nIE DISCLO-3-UR-ri A rnobile impacti@ig riachir@e having an impactintool mount ed for reciprocation in a mast carriecl by a power driven vehicle and selective' y sivingable from an 1,jpright 1,5 ,,vorki n- position to an approxirnately borizo:ital storag,3 positio n, the mast b@-ing mounted to traverse an end of the vehicle durin.- operation. Backg razind 20 Mobil e impacting machines -perform many jobs in the constr -uction and road buildin.- ir@dustries requiring a hammerin g or p.-rcussive action, including breakin,@ concrete, driv.,n. - posts and pilings, cutting asphalt, and - tampin.a 25 back 'ffl. The harnmering action is generaliy provided by raising a wei.-hted impacting or percussion tool al()ng guides a-?id allowing it to descend by gravity rapidly a@ld heavil y a,-ainst the work with the tool bein.@ @uided in its free fall alon- a vertical or near vertical mast. The 30 weigh ted tool a-nd guides are mounted on a power driven chassi s by a support nember. To obtain the versatility req-uired of a macline of this ,type, it is necessary that the mach;ne b-- easily and quickl y adjustabla to alter the position of the tool and 35 ,- Uides to direct the hammering action wher-- it is needed. For certain operatioijs, a hi-Lh degree of accuracy is required in the hammering action. In CDncrete or pavement breakin.-I it is necessary tha-t the hammering tool be accurately movable iq small increrpents aiong the work 40 line. In tampi@ig or compacti-Tig work with such - machiies, the force of irqpact is depo-t2dent upon the hei,,ht to which @the tool is raised, and it is desirabl-. to be able to contro l the drop distance. It is also dasirable Criat the weigh ted tool and carria.-c be adjustable to permit hi.-h- 45 sp.-ed, over-the-road travel to the job si@te -@vhile also allowin.- for a creepir.-, drive wben working. In addition to the abdve criteria, it is imperative that the mobile har@amerin.@ mach@'ne be ru,-,-edly built to v4thstand the rei)ititiol@s shock s of the ha-mmering action thro-aghout the useful life .51) of the machine. As the support -Trember provides the mount for the hamm ering tool on the machine, the attainment of the above stated requir@-ments of versatl:lity and rti@@edness is ber, particularly since support members employed in the past have not permitted complete attainme.-it of all th-,se desira ble features. Summ ary It is therefore an object of the present invention to pro- 0(" vide an improved portable ir-lpacting machipe which obviates the disadvanta.-cs and objections attendant prior machi nes of this -eneral type. Accor din.-ly, the present inventi-on provides an im'15 prove d mobile impacting r@iachine having an improved suppo rt member and power actuatin.- and control means for the hammering tool which are mechatiically stron.- enoug h to resist the shock of the haminer bloivs yet which pprmits accurate stroking and positioning o-f the tool. Furtb er, the present in@iention provides an improved mobile hammering machine havin.- a readily adjustable particularly focused on the desi,-n of the mem- 5Fj Patente;d Jan. 23, 1968 2 drive and traverse means which is sui-neiently flexible to enable positi4Dnin@ and actuation Df the hammering tool to a variety of w@ork positions which additionally rendering the same suitable for over-the-road tr'avel. The drawitigs Ot'iaer features a@-id advaiitag--s of the present invention will become apparcrit from the following specification and drawin,@s, f orming a t)art thereof, wherein: FIGURE 1 is a perspective view of a typical mobile hammering machine embody;-Ti- the improvements constitlitina the prese-@it invention; FIGURE 2 is a fragmcjitary part-sectional view of the mast su,,3port and carriage rileans employed in the impacter of FIGUP-V 1, tak,@-@n along the Iiiie 2-2 of FiGURE 3; FIGURE 3 is a@iother fra,@mentary part-sectional view of the support and carriage means, taken along the line 3-3 of FI'CRURE 2; FIGURE 4 is a fragm-entary view taken along the line 4-4 of F'IGURE 3 and iticluding the driving means for traversing the mast support and carria,-e means; FIGURE 5 is a fra.-Mentary rear view taken in the direction of the arrows 5-5 in FIGURE 2; FIGURE 6 is a fragmentary s@.@-tion throu.-h the drive and transrnissio@i mechanism of the transporting vehicle with the parts shown in posiion for conventional over-theroad travel; PIGURE 7 is a similar section thro,-lgh the drive mechanisrii <)f the vehicle bv!t with the clutch for conventional drive disciiaaged and the hydralilic creeper drive in effect@ve workin.- coridition; and FIGU-RE 8 is a schematic diagran-i of the hydraulic syelem ernployed by the mobile impaoting mac@hine of the present invcntion. Detailed desci-iption Turn,n- r.-ow to the drawings, FIGURE I shows a mo" I bile impacting machine designated generally by the number 2. 'rrie macbine has a chassis 4 on which is mounted a rear c-ii.-ine 6. The machine is steered by the wheels 3 and propelled by the wheels 10. Dual drive wheels 10 may b, utii:zed to better stipport the wei@-ht of the hammering or iirpacting tool. Brackets 12 moii-ilted on the front of the vehicle chassis 4 between drivi.,-ig wheels 10 pivotally positions the tool suppoi-t member 14 vihich extends transversely across the front of chassis 4. A carriage 16 on the support member 1,-S provides a mounting for guides 18 which form the mast and extend vertically upward. Slidably pc)sitioned oii guides 18 is hammering tool 20 which cc)nsists of wei.-ht 22 and a workplece 24 in the nattire of a tampin- tool, breaker or bit. I;Vhile a tool suitable for tampin@ . is shown in F@TGURE 1, it will be appreciated that the tool may b@- chan@ed to fulilll the requiremer@ts of the job at hand. For' example, a sharpponted, @ved.-c-shaped -tool may be utiliz--d to cut asphalt while a blunt, wedge-shaped tool may be used for breaki-ng corcrete. Hammering tool 20 is raised alo-ng guides 13 by cable 26. The operation of the iriipactin@ or hammering tool 20 is contro'@led by th.- hvdraulic s ystem shown in the varioas flg@Lr-,s arcl shown '-ti seiiematic detai'@ in FIGU,-RE 8. A hydraali,- ey!inder 28 mouiited on guides 18 controls the raisin.- of hamri-ierin.- tool 20 al@ong its normally vertical guides. The pi,@ton rod 3,1 of hydraul;c cylinder 28 has a bl -,ck arid sheave '-2 mounted thereon. A cable 26 is strun@@ from hammf--ri@ig tool 20, through blocks and shfaves 3A, 35 at the top of gui-@les 13. through block 32 to a@q anchor at Llic top (>f guides 13. A retraction of pisto@-i 30 into cylinder 23 serves to raise hammering tool 20 to a r,@-ed,-termined height as det-,rmined by a control means hereinafter more fully described.

3)365,005 The sideways tilt of the mi ast to the left or right iscontrcvlled by hvdraulic cylir@der 318 which co-Titrols the positionin@ of guides 1,3 about a pivot located on carriage 16. The 'Lore and aft t-'Lit of ---uides :1-8 and hammerina tool 20 is controlled by a hydraulic cylinder 40 con5 nected to arm 41 which controls the position of pivoted support member 14. By fully extendinhvdraulic cylin-der 41,1@, support meirber carria,@e 16, @Uides 18, ar,.,d hammering tool 20 may be tilted to the rear alorg the right side of the vei@icle s'affici--iitly to enga,e a catch 42 as it) shown in phant(ym in @F@IGURE 1. Catch 4-2 retains the aforemeptioned structiire i-@l the rearward 1),osition to p-,rmit over-the-road travel. Also, -,) safety hook or latch may be prov@.ded for retaining the mast i@i its raised working positiorl. 1:@ Turning now to the transverse support riiem-ber 14,, such membe@- i-,ic,ucles a fropt rai 4.6 hav' - an uI in, _,)p,-r ffange 43, a lov@,er -,9an.@e 50, a--,id a conr@ecti@-i.@ web portioti 5Z. AJso iiicluded is a rear react-loii me-,nber 54 havin,- a laterally extendln,- gu-ide flange 56 mounted on the @0 upper Dartion thereof, the flai@,,e 55 extendirig rearwardly away from the -f@-o@--it rail 46 as shown. R-@il 46 a-,id, member E4 are rigidly sdpporte,,' a@id retained iii la',erally spaced loi-gitudinal al;,-,ime-@it i-ii approximatel@y t@@le same horizontal pla@ic by a p'iurality of laterally spaced Ushaped 25 meriiberg 58 joined by a front beam nen@oer 60. Traversirig the IoNver medial portiois of the U-siiaped bracke-Ls 53 is a pivot mount@'@n-, means 62 exteriu'i-,l.- transversely of the vehicle aid adap'Led to mate vv;th b.-qckets 12 to perinit support me@nber l@l., carria.-e 1-6, a-@ic-1, t@e Pssociated -uides 18 and hammerzn,, tool 20 to tilt fo@re and aft. Also mounted on the U-sliaped brack-c'ts 1-@8 -is a toothed rack 64, which extends upward from the brackets 53 aiid has a runr@in@, surface 65 on the fo,-ward ed@-c thereof. 35 TI.,e carriag,-- 16 incl@udes a tubular meniber 66 positioned transvers@ to the support meinber 14 and to the, axis of pivot means 62. A shaft 68 is joumalled in tubular member 66 and fastened 'Lo the -Car of giiici,-s 18 to provide a bearin,@ means for the '@Cft and ri.-bt t;ltin.- 4( of -Uides IS and hammering tool 20. Mou-@ited on the lower portion of tubular m--mber 66 is a cha@=el W."Mber 70 ha-ving an outer dep--rxdi-iig p--rtion 72, a toD pertion 74, and an i-Tiner de-pendin- portion 7fi. Chan nel 70 straddles the fron, rail 46, qiid a pair o'L larae i,an.-ed 4,5 rollers 78 are rotatably mounted o-n outer porticn 7Z of channel 70 a-@id are peripherally sui)ported on ene run of the lower flan@e 50 of rail 46 adjacent @Nieb 52. Ti-@e rollers 78 are peripherally spaced fron til-ie li-,Dper flan,-e 48, a-id a pair of smiller rollers EO are adjustably mount- 50 ed on the le.a 72 of member 70 to engage upper fian,@e 43 c>-'L rail member 46. An additional ra;r of large 'tlanged rollers 82 are niounted on tlle i-Tiner dederiiin,@ leg 76 of channel inember 70 to peripherally eng-a.@c @l@ travel o-Ti the other r-an of the lower flan,@e 50 o@'! rail member 46. 55 The carriage is thus s-apported by the rollers 78, 82 - @vhich are adai)ted to travel along the cppositely direc,led rdns C', ti of the liower flan.-e 50 o'L the rail 46. Als 'le rollers 80 are adjustable to proderly peripherally enga@e the upper flanae 48 o'L the raii 46 and thus aid in m'aintaining 60 th-- rollers 78, 82 in proper peripheral contact with the flange 50. To cornplete the supi)ort and stabii;ze the structure, a plate 1,@,6 mounted o-,i the rear end of tubullr meirber 66 contains two pairs o@' unflang@-d rollers 38 and 90. These 65 rollers ar-- spaceci to coact w.;th -u;de flan.-e 56 of the member 54, and it is preferable to mount 'Lhe rollers 33, 90 at an angle to the rol'iers 78, 82 as sho-,@.,n for most effective stabilization and 'Lo mip;-qlize bindinand the need for accuratt@ ali.-ninent of the roller axes. 70 It will be appreciatcd that the above described structure provides a rugged, yet acei-irate, ino,,inting for car-ria.,e 115 and the attached -uides '@8 and ha-nimerir@.@ tool 20. l,pecifically, the roll--rs 70, '@12 in cbnjupction ivith rollers 80 a-@id rollers 53, 90 prevei-il @andesirable vei-L@,,al rilovement 7.5 4 Oa ca-rip,.--. 1-1,, in rel,atioti to si-inport meinber 14. These roller's effectivel@y support and stabilize Nvhiie also preventin,- any pivot'n- of c.,irria@e 16 about rail member 46 or llate and 'he fianges on rollers 78, 82 prevent any !on-iludinal cisplacement of carr-age 16. The nn.-r depcnditig 1,-@ 76 of chE!,r@iial member 70 has af,@x-.d thereto a @nountir@.- bracket 96 for a hydraulid mo'Lor 4.,A. Tho motor 44 has a gear 100 keyed to the output shaft 98 -,@@,hich meshes with a piniop gear 102 to drive the saiiie. Pinion gear '@-o2 is, :.I turn, totatably m-c-Lnied o,.i a shaft 97 @vl-iieh is carried by the upper and icwer ar-ms 99 L-nd !&! of a frame meniber 104. T17iese ar---,is of 'he fra@iie member @-4U. also co.@itain bearin.&s for the -ear IC@O driv-@n by output shaft of mcytor 44 and support shai-t 97. Ti'ie frame mer-ribe,- 104 is rWLatively supyorted. by m@-at-is of a clamped split rin-, .105 surroundirig beari@i- '07. The positioti-@ig member 103 loosely receives the shaft 97 at its upl,)-,r portion. The member 103 s-@rves to carry th-. ro"ers 84 wh,' coagt with th,-- runnh-ig I @ch surface 65 oii the forward ed.-c of rack men-iber 6,4- to riiaiiitai-,i 'Lhe gears in proper position and aligmhe-,lt@ The loosf- f-it of sbaf, 97 in the men-iber 103 thus uermits the attached. ho@:-izoital frame i-.,icmber 104 aIGng with the pinioi, -ear 102, and shai-t -l,7 to pivc)t slightly about the outout shaft of hydrauiie motor 44. Iii other wo.-ds, the _r. ame m--mber 104, in cooperation viith the rollers 84 .LE ar!d atl-@idant st:,ucture, provict-,s a 2oating support coupliri-@ the 1,00, IG2 and swiii,@able to a limit@-d extent abc>@@it the shalts c@7, 93 to the@-eby i-naintain proper gear ptc'ii line co-.itacl wh@'@'.e providin@ for so,-Lne small amount ol'L lateral disi3lacem@-nt between the beam structure 14 with rqck 6,, a-.id carria,-e 16 with -tnotor 44. As sho,,vn in FIGURE 1, ha..qmerin- machine 2 has an op--i-ator's control station vvhich includes a seat 106 and steerin- ,vheel 103. Aiso provided at t@ie contrc)l station are the ciutch, throttle, ancl gear shift 1-@vers of the ordinary type I-or controllin- @notor 6 and a plurality of valves ap@l: sciective controls fcr controlling the abc)ve-described hydrall;c cylinders, hydraulic ir@otor and cree-oer o@peration. These controls e@iable the operator to control vehicle trave'i, proper positioning of the mast and iLs attendant r@iechariism, hammer actuation and creeper movement all froin a singlo statioti. R.-ferring non@i to FIG@-LJRFS 6 and 7, the improved mechanical-hydraulic drive and cluteh mechanism for the vehicle is illustrated. A f@-agment of the conventional vehicle tra,-lsmission is identified by the numeral 150, and vvhen the vehicle is traveling frbrn site-to-site over a highway, it is driven in a convent@onal manner through t@he shaft 151 coudled to the ffywneel 152 by the clutch 153 which nlay be ol- any wellknown type having a face plate or disc 154 er-gageable as in FIG. 6 to drive the vehicle ;,i a conv-ntional mann.-r. The clutch 15,3 is ret@.-actable': throtigh @ini@a,-e 155, 156 i@-_Pon shiftin.- of a lever convenient to the ol)erator and coudied with a motio-Ti transmissior, shaft 1,57. Retraction of the clutch 153 at the will of the operator disengages the disc 154, and the vehicle e--rive inechaiiism may theii be powered by hydraulic means at a sdeed si-,Hlciently slow and/or intermittent @o perr@ait effective work performance by the inipacting tgol. To coup'@e the vehicle drive mechanism to the hydraulic systern, a sli;.Lt lever 158, also convenient to the operator, is con-iiec@e-i to a shiftable g,--ar 1-50 as by means 6f throwout or actu,,iting shaft 161 and suitable linl,--a,-e. Thus, wi@h the eciiv@-ritional transmission uncoupled 8 shoivn in FIG. 7, x-ovement of the leve.- 153 to the right NEI shif@ the gear 160 into mesh with the gears 163 and 165 to @ereby comnlete the drive cliain from the hydraulic motor 168 to the vehicle drive shaft 151. The hydraul'lc motor will accordingly drive the vehicle at a desired creeper or slow and/or intermitt-,nt rate of speed wh;ch may b--- readiiy tim@d -@vith or adjusted to the hammer op-ratio@l by the operator by select@'.on of gear ratio through staidard t@-arismission 153 and actuatioil of hydraulic con-