US1747430A - Trimmer-saw lift - Google Patents

Description

Feb. 18, 1930.

G. w. DoRMAN TRIMMER SA'W LIFT Filed Sept. 15, 1928 4 Sheets-Sheet l mw Q, vk.

Feb. 18, 1930. Q W, DORMAN 4,747,430

TRIMMER sAw LIFT Filed Sept. 15,` '1928 4 sheets-sneer 2 Jaap/77er.'

Feb. 1s, 1930. l G, w, DORMA 1,747,430

TRIMMER SAW LIFT Filed sept.'15, 1928 4 sheets-sheet l 5 man!!! Feb. 18, 1930. G. w. DORMAN TRIMMER SAW LIFT 4 Sheets-Sheet 4 Filed Sept. 15, 192B Patented Feb. 18, 1930 UETE'D STAT' TENT F15 marianna-saw LIFT Application led September 15, 1928. Serial No.` 306,126.

My invention relates to vn'iechanical lifts for trimmer' saws, and similar devices, in which a work-performing element is to be placed into and out of its working position.

commonly used in saw mills, for trimming the lumber to standard lengths, are driven continuously but are normally out of working position, and one or more are selected by an attendant and lowered to the work.

The principal object of my invention is to provide a mechanical, manually controlled trimmer saw lift, conveniently operated by the attendant to Araise orl lower the saw into and o'ut of working position, and the lifting and lowering mechanism then to become automatically disengaged, thereby to hold the saw lift in its assumed position until ag'a'ixil manually operated by the attendant.

Another object of my invention is to provide a mechanical trimmer saw lift positive in action, relatively simple in construction, simple to" operate and durable in service.

A. further object of my invention is to provide a trimmer saw lift, consisting of devices adaptedn and arranged to be enclosed in va housing. adapted for holding a substantial volume of lubricant in which the operating parts run grand furthermore protecting the operating parts fromr dust. Furthermore, such housing shall be made of such relatively narrow width that the individual units of the battery of saws may be placed as closely together asl desirable. A r I attain the said objects in al combination comprising a housing, a shaft journaled therein, ka primary sprocket fixed on said shaft, an idler sprocket alined with the first mentionedv sprocket, av sprocket chain running on said sprockets.,v alift-device including rod connected at one end to said sprocket chain; a' driving element normally connected to said shaft, and a manually operated control, whereby to'disconnect said driving connection such control comprising devices arranged to disconnect automatically said driv ing connection from said shaft, and'stop the rotation of the latter, at the end of each half-,

circuit travel of said sprocket chain.

@o While I have described my invention with s well known the gang of trimmer sawsv reference to its particular use in connection with trimmer saws, of course I do not restrict myself to such use, but the combinations inclnded inl my mechanism also serve as a combined clutch and stop mechanism useable for other devices' than trimmer saws.

The mechanism combined in my lmechanical lift, the features thereof, and-its mode of operation are hereinafter fully described with reference to the accompanying drawings. Y

In the drawings:

Fig. l shows a diagrammatic side elevation of one unit of my trimmer saw lift mounted in place, and operating rone of a gang of trimmer saws Fig. 2 shows a perspective exterior 'view of one of my trimmer saw lifts, and a part of the rod connecting the same toA a trimmer saw; l Y f A Fig. 3 showsa perspective view similar to Fig. 2, except that the upper half of the housing has been removed to disclose the parts contained therein; i

Fig.' 4 shows in elevation a fragmentary larger scale detail of the sprockets and the sprocket-chain running thereon;

Fifr. 5 shows in a fragmentary View the mechanism contained in the housing, a portion of the gear being broken away to dis close the devices covered thereby; this view of my mechanism being from the' opposite sidet'o that shown in Fig. 3;

Fig. 6 shows a fragmentary sectional view similar to Fig. 5 with the operating parts thrown into another position;

' Fig. 7 shows a fragmentary sectional" view` similar to Fig. 6 illustrating further phases of operation; l

Fig.'8 shows a longitudinalsectional `view through the housing, also the gear normally loose on the drive shaft, 4part of the" devices v Y` operable to connect the gearfwiththe shaft, and the.V driven pinion driving the gear. This view is taken from the same side asV Fig;

' 9 shows a ltransverse section 'on the line 9-9 of Fig. k8 showing onlya portion of the casing, the driven gear and the shaft therefor;

lul

Y Figsf'lO and-'11 showin perspective 'i disfmounted vparts. of myL mechanism;

` ,-12'is a view'similarto Fig. 5 illustratinganother phase in the operation of my inve`nt1on;j l Y ig. 13 shows va section taken on the line 13-13'of Fig. 12 looking in the direction ind icated by the arrows;

Figs. llland 15 show a detail in side eleva-'iv Vtion and end elevationrespectively, of what I term the transmission element ofvmy mechanism;

nislnshownin Fig. 16;

f Fig. 16 shows on alarge scalea vdetail of saidV transmissionv element and cooperating devices; f

l(Fig. 17 shows in end elevation. the mecha- `Figs. 18, 19 and 2O and showsvfurther someof the parts carried 'byvsaid transmission q element but removed therefrom; Vand n f f; Figs: 22 and 23 show respectively, in side elevation and topview details of what I term the primary stop-bar. i Y

Referring first to Fig. 1; a represents one of a battery` of trimmer saws, each keyed on .a shaft as b carried'by an arm, or lift device e,`pivoted on a shaft c.' The extremity ofthe armV e is connected toa rod f longitudinally `adjustablewitharodt, the upperkend ofv l which is* connected rto Vthe mechanism provided by me for raising and lowering theL arm e, andfor automaticallyreleasingit'from.

theiraising and loweringv devices, when' the saw isl'either inits up or its `down position and then holding it in thatrposition until my Vmechanism is againmanually actuated for placing-'the saw 1n anotherposition.

The saw a is driven continuously and V,is normally lifted from the saw table Z as usual; the saw being raised and loweredy from and to .thejj'work table by the manual control of my mechanism.

.Y My invention'coniprisesa housing 2V firmly 1 mounted by suitable supports 3 abovethe saw as indicated in Figs. 1 andg2.; The'housing, for convenience, may beconstructed 1n two sections, namely a' base and ak top part as isjournaledin thehousing as atb?L (Fig.2)

and onsuch shaft is keyed a pinion 7 meshing with al gear 8 krotatably vmounted Ona ' stub shaft 66,1`prrovidedfon' the exterior of' the baseV portion of lthehousing 2. A sprocket show inperspective Y other ldismounted parts of my mechanism;

Fig. 21 shows alsection ofthe transmissionl element taken on the line 21-21 of Fig. 16,V

chain 63 is mounted overthe saidsprockets.

The upper .endof the rod 64 is pivotally connected tothe said chain by a special link 63LV on a pin 641, and the lower end of the rodjis connected to the saw as mentioned. 'Ior accommodate said arrangement each of the said sprockets have a portion cutaway as aty 61a,

62a. The chain andsprockets areso relatively proportionedv that two rotations of the- `Sucrockets willcause one complete revolution Vorcircuit of travel of the chain. i 'Y f y Onthe driving shaft 9 is fixed a transmis- .sion element 11, a detail which isfshown by itself' in side elevationand end elevation in Figs. 14 and 15, respectively, andis further shown on a larger Vscalein Fig. 16 wlththe parts mounted on said transmission .element and (operating therewith, andagain kin Fig.l 2l, which is a section on the line 21 of Fig.v 16, showingsaid transmission vrelement with some of its parts `removed,.but arranged for assembly on the transmission element. The

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transmission element 11 has a prejection121 (see Figures 14 and 15) and isprovided with- y w a bosses 13, 14 andvllia, in; whichfarepivoteid certain operatingparts and has a flat surface 15 on which slidesa block 18secured in yplace by p'ins'18a (seeFigs. 16 and 21).. A dog V17 is pivoted for rotation by `axpin VV13av on the transmission element 11, as shown'V by Fig. 16..A

A perspective detailV of this dog is shown Fig. 20. It comprises a `toe 17 and ahead! 17'?, with the head vbeifng'ada'pted to ybear V'on the projection`12 of the `transmission element 11 and the toe-17EL adapted to bear against the slidable block .18, as more clearly shownl by On the boss 14a of thetransmissionelement i 11 is pivoted a primary angular pawl131A by alpivot pin 19. A detail of thisdogis shown in'y Fig. 19. It consists of a` sleeve'rpkortion j 19a integral with which is Va toef30 andispaced ears 32. There is further pivoted at 14 l'on the' i transmission element 11 asecondary pawl Y 31a, lthev construction of whichis similar toi. the primary pawlf31.'v The perforated .ears 32 of said pawlshave secured Vthereto a U5y shaped expansionspring 33 bypins 33?'. The

spring 33 'when unrestrained,"'positionsythl. 1153'Vv pawls 31'and 31a as shown in Fig. 7, thus engaging the same with the internal ratchet teeth of the gear 8, in so doingA the toes .3G-of f the pawls 31 and 31Pbear down ongthefsliding j' block :18` and cause thejsune to rock 1the dog.N i' l17 Vinto the position in whichfitus shownrin" Fig.` 7 In the Vpositionfof the Yparts lastre-U1 ferred to thefgearjSn'is connewtnzted with .Y

driven shaft 9. f

In order to'vdisco'nnect the., ytransmission element 11 fromthe gear 8v andsimultaneously holdtheshaft? against `further rotation.. Y

Igprovide a ,stopl mechanism consisting of a Y primary stop-bar 4 4, j and a secondary stop-V bar Z10,; these stopbars being pivoted to onek sidewall 0f the;housiflsasshowii infFig-S.

5 and 12. The free ends of the said stop bars are pivotally connected to a rocker arm 43. A detail of the primary stop bar 44 is shown by Figs. 22 and 23. It comprises a boss 44a by which it is mounted on a pivot shaft 45 journaled in a wall of the housing 2. The free end of the stop bar 44 is provided with a slotted head 44h; and rigidly fixed on the outer end of the shaft 45 is a cam arm 44.

` A. detail of the secondary stop bar 40 is shown by Fig. 11. The free end of the latter .st-op bar has a head 41 provided with a slot 42. A detail of the rocker arm 43 is shown by Fig. 10. It is mounted on a pivot pin 43a provided in the adjacent wall of the housing. The slotted head ofthe primary stop bar 44 is connected to one end of a rocker arm by a pin 42b`and the slotted head of the secondary stop bar 40 .is connected to the rocker arm by the pin 42a. The rocker arm is normally held in the positionin which it is shown in Fig. 12 by a rod 51 on which is placed an expansion coil spring 52, the compression ofv which is adjusted by a nut 52a. The rocker arm is operated by a bellcrank 54 to which is connected a cord 55 leading to a distant point as a, in Fig. 1 where the attendant is stationed. The bellcrank is pivoted on an arm 2b mounted on the cover of the housing as at 2a, and the bell crank is connected to the rocker arm 43 by a rod 53. v

By the description of the parts of my mechanism, above given, its operations will be readily understood. Initially my mechanism has been so manually operated as to position the sprocket chain 63, as shown in Fig. 2, in which position the rod 64, and its extension f to the lift-arm or device e has been raised so as to lift the saw from the work table.

In Fig. 12, the transmission element 11has become positioned feo cause the dog 17 thereon to abut against the primary stop-bar 44, which abutment has caused said dog to move the slidable link 18 against the toes 30 of said primary and secondary pawls 31, 31a and thereby release the latter so as to retract them from the internal ratchet teeth of the gear 8; and since the transmission element 11 is fast on the driven shaft 9 thelatter is held against-rotation by the abutment of the dog 17 with the primary stop bar 44. I-Ience the sprocket chain is held stationary for the timevbeing. In order to changethe position of the saw, that is, bring it down to the work, the attendant pulls thebell-crank 54 clock wise as shown in Fig. 12, and thus rocks the rocker arm 43 counter-clockwise, in so doing lifting the primary stop arm 44 from the position in which it is shown, and hence releases the dog 17, which release permits the spring 33 to act to throw the pawls into engagement with the internal ratchetl teethA of the gear 8 thus connecting the latter with the driven shaft 9 through'the medium-"of the transmission mechanism. Since the shaft'9 is then driven by the pinion 7 through the gear 8, the sprocket 61 fast on said shaft willl be rotated. The rocker arm 43 and the stop bars 44 and 40, -have now been givena position similar to` that shown Fig. 5, thus lifting the primary stop bar 44 to its inactive postion, and lowering the secondary stop bar 40 to its active positiomwhich causes it to arrest further movement of the transmission. The saw has now been lowered toits work as mentioned. Y

In order to again lift the saw from the work table the attendant will release the bell-crank 54 so that spring 52 may function to rock the bell crank counter clockwise into its initial position, bringing the rocker-arm 43, and the primary and secondary stopibarsk back into the position in which they are shown in Fig. 12.

rlhe dog 17 being thus released from its abutment with the secondary stop-bar 40,the transmission member lland therewith the shaft 9 may again rotate, but as evident from Fig. 12 the parts have now become so positioned that the primary stop-bar 44 would be in the path of motion of the dog'17. In

order to permit the dog to pass, means must be provided to lift the primary stop-bar 44 at this instant. To this'end the sprocket; chain is provided with a projecting link 70, in which is journaled a cam-roller 71, which `is arranged toV contact with the cam-arm 44, an integral part of the primary stop-bar 44 as above described, and thus by lifting said camarm also lifts the primary stop-bar 44 out of the way of the dog 17, so as to permit the further movement of the transmissionmechanism and therewith the rotation ofthe shaft 9 ,and as soon as the cam-roller 17 haspassed' from under thel cam-arm`44c the latter will, of course, drop and cause the primary stop` cui loo

bar 44 to resume its position in Fig. 12,l and thus again arrest vthe rotation of the trans'k mission element *andY the shaft 9 when the sprocket chain has completed another halfl causethe sprocket chain to travelv half its length; or, in other words make a half circuit of itstravel. j,

It 'isto be'noted that by my mechanism the lifting and lowering of the trimmer saw from and to its workv is not done by 'any sudden jerk, but by a uniform though relatively rapid motion.

closed in a dust proof casing, the lower pa-rt of which may be kept filled Vwith lubricant, and furthermore, the casing is relatively nar-- row,thus permitting the ltrimmer sawsto be set'closely together as desirable.-

Y Furthermore, all moving parts except the chain and sprocket are in- 1,0v Y Y i n VsaW, both-1n the lowering andraising oper- Y ation, *I is z positively actuated, insuring ay Itis to be particulary noted that the combination presented by the above structure involves'a continuously driven elementand 4the that suchlowering and lifting means is Vpositively vdriven,bothfor lowering the saW and for raising'it. Thus, the'moveinent of the steady, y,even descent'and raising movement of thwSaW, with the rapidity of such rmovement depending upon the speed of movementof the kcontinuously drivenfelement and thus in` no- 41 v vise depending in any Way'upon they Weight ofthe saw Vand its mounting and insuring` that the operato'rmay positively control both low'- `ering and raising movements to Ainsure that v Y With, and cooperating means' provided on i the lower or operativeplane ofthe saw Will, YVsubject tothe initialmanual adjiistmentof i ,v the connection of the lifting rod, always be the same operative plane Without thepossibility of variation `and Without the liability of error. Furthermore, it will be noted that the 'Y continuously driven4 element makes substanstantiallya complete revolution in each loW- ering movement` of the sawV anda complete revolution in eachjraising movement of the saw.y vkThis provides for a: simplificationof the control of the movement inithat 1n each lowering and raising` movement, Athe con-f nectionwith the continuously-driven element is interrupted at substantially thesame point.

Ilam

v1.,', Inal saivflift and the klike,fthe lcombination:A of,';a revoluble shaft, a primary sprocketrfixedon said shaft, an-idler :sprocketalined Withthe first mentioned sprocket,a4 -sproclret'cliain running on said sprocketsfthe i diameter of eachof said sprocket Wheels andy v thel'engthV ofV the sprocketrchain being pro- `portioned to move the chainrhalf its path of travel upon one, complete revolution of the sprocket Wheels, a lift device including aL rod connected at one end to said sprocket chain,

' a gearjloose `on saidshaft`,a difivenpinion Y inrmesh with ,said gear,atransmission element fixedon said shaftf and includingfspringlcontrolledmeans normally engaged with said geanto positivelyfoperate the chain:th-frough-j Y -outffull revolutionof the gear,;a stop mech-v anism carried by said transmission element,

Isaid stop mechanism' operable vtofrender 'said-2 l g gear-engaging.V means inactive and ,manual-Y" Yly controlled devices arranged to .engage f and hold'V said stopmechanism and simultaneously to, operate the same toreleasesaid gear fat the end ofeach full revolution of the gear i :and each half-circuit travelof said sprocket "chain Y I sprocket fixed on said shaft, an idler .sprocket allined Withthe first mentioned sprocket,

sprocket chain vrunning on said sprockets the diameter of each-of said sprocket Wheelsand i the length of the ysprocket chain being propinion in mesh With said geara transmission t element fixed onfsaidshaft and'including` spring-controlled. means f normally engaged With said gear throughout one complete revot i lution of the gear, va-stop mechanism carried by said transmission element, said stop mechanisin operableto render said gear-engaging means inactive and manually-controlled Vde- "vices including a, spring-controlled rockerarm, stop-bars p ivoted adjacent'the extremities of said rocker-ai'm'and connected there-1 tlie sprocket-chain and on oneofvfsaidstopbars adapted to lift the latter intoinactive :position in one position of said transmission element.

shaft, exterior of the housing, an idler sprocket carriedby the housing and alined-Withthc first mentioned sprocket, ka sprocketv chainv running on. said sprockets, thev vdiarneterof each` of said sprocket Wheelsv and,l thelengthVV of thev sprocket chain beingproportioned to move the chain half lits pathof travel upon` one complete g revolution of the sprocket Wheels, a lift device including@J rod connectfed at-,one end (tol said sprocket chain, afgear -loosehon said shaft Within the housing,a

driven pinion journaled in ,said Vhousing in r mesh With said gear, a transmission element fixed on said shaft and" including spring,-`

controlled pavvlsnormally engaged. with said gear, a stop mechanism carried by saidY transmission element, said stop lmechanism l,operof the gear, and manually controlled devices im j able to `render said gear-engaging` paivls inl active following each complete revolutionY circuit travel of said sprocket chain. Y l l 4. Ina saw lift and the like, ythe combina- 1 tion of', a housing, ashaft journaled infsaid housing, aprimary sprocketfiXfed on -said shaft exterior of the housing, an idler sprocket carried bythe housing and valineol'vviththe first mentioned-sprocket, a' sprocket chain of the'sprocrket chain being 'proportioned to.

n Y y (l ,t Y, ,Y lmove-thechainhalfits'pathof travel upon a -saW` liftandthe like, the ycoinlfri-v l Ynation of,.a revoluble shaft, a primary lcnef-.comlolete revolutionV of the sprocket Wheels, a lift device including arodv connectgedat one end to saidsprocket chain, a ,gear- Y,running jon saidsprockets,the diameterfo'f eachvk of Asaid sprocket Wheels andthe lengthv looseon said shaft within the housing, a driven pinion journaled in said housing mesh with said gear, a transmission element fixed on said shaft and including spring-controlled pawls normally .engaged with said gear, a 4stop mechanism carried by said transmission element, said vstop mechanism operable 'to render said gear-engaging.. pawls inactive following each complete revolution of the gear, and manually controlled device including 'a spring-controlled rocker-arm, stop-bars p ivoted adjacent Y the extremities .of said rocker-arm and connected therewith, and cooperating means provided on the sprocket chain and on one of said stop-bars adapted to lift the latter into inactive position in one position of said transmission element 5. in a saw lift and the like, the combination of, a housing, a shaft journaled in said housing, i Primary Sprookot ilod on said shaft, lan idler sprocket carried by the housing in alinement with the first mentioned Sprookottho diameter of each of Said Sprooket Wheels and the length ofthe sprocket ychain Y tion of the sprocket Wheels, a sprocket chain running on said sprockets, a lift device in.- cluding a rod connected at one end to said sprocket chain, a gear loose on said shaft Within the housing, `Said gear provided with e Peripheral ,denso andsad flange provided with internal ratchet teeth, a driven pinion journaled in said housing in mesh with said gear, a transmission element fixed on said shaft within said flange of the said gear, primary and VSCondary angular spring controlled pawls included in said transmission element and normally engaged with the said internal ratchet teeth of said gear, la .spring controlled rockerfarm pivoted in said 'hou'sf ing, manual means for tilting such rockerarm, lprimaryand secondary stop-bars pivotod, roSpootf/oly, ediaoeut the extremities of said rocker-arm and connected therewith, ak

slidable block arranged to bear against one leg of said pawls respectively and a dog piv oted on said transmission element bearing against said slidable block and .adapted to abut with said stop-bars, thereby to be operated to move said block into position for retracting said pawls.

6. In a saw lift and the like, the combination of, a housing, a shaft journaled in said housing, a primary sprocket fixed on said shaft, an idler sprocket Carried by the housing in alinement with the first mentioned sprocket, the diameter of each of said sprocket wheels and the length of the sprocket chain being proportioned to move the chain half its path of travel upon one complete revolution of the sprocket wheels, a sprocket chain running on said sprockets, a lift device including a rod connected at one end to said sprocket chain, a gear loose on said shaft within the housing, said gear provided with a peripheral flange and said flange provided with internal ratchet teeth, a driven pinion journaled in said housing in mesh with said gear, a transmission element fixed on said shaft within said flange of thesaid gear, primary 'and secondary angular spring controlled pawls kincluded in said transmission element and normally engaged with the said internal ratchet teeth ofr said gear, a spring controlled rocker-arm pivoted in said housing, manual means for tilting such rockerarm, primary and secondary stop-bars pivoted, respectively, adjacent the extremities of said rocker-arm and connected therewith, a slidable block arranged to bear against one leg of said pawls, respectively, a dog pivoted on said transmission element bearing against said slidable block and adapted to vabut with said stop-bars, thereby to be operated to move said block into position for retracting said pawls and kcooperating devices provided on ,the sprocket chain'and on one of said stopbars adapted to lift the latter into inactive movement during'one position of said transmission element.

7. The combination with a trimmer saw mounted for movement into and out of an operative plane, of means for moving the saw into and out of said operative plane, said means including a continuously and' posi- -tively driven element, a fmember mounted for travel in an endless path, a connection between said member and the saw, and automatically operative manually controlled means for connectingsaid member to the positively driven element for actuating the member positively throughout its fiill'path of movement, saidl means adapted to automatically interrupt the positive connection between the member and saidelement'atthose.

inoperative plane, of means for moving the saw' into and out of said plane, said means including a continuously driven element, a member mounted for travel in an endless path, aconnection between said member and the saw, `means for positively connecting-.said member to the continuouslyy .driven Aelement adapted lto cause the movement of said vmember in response to the movement vof the element, automatically operative stops adapted Vfollowing each successive complete revolution of the element to disconnect .the member from the element when the member has moved vthrough substantially one-half of its path of travel, and manual means for controlling the automatically operable stops.

9. The combination with a trimmer saw mounted for movementintoand out of an oper ativo rlanoiofmeansfor movrleflio .Savfseid vme ans including continuously driven. element 'formed with aratchet, ameniber mounted to travel in an endless path', a connection Y lbevtween said memberand thesaw, pawlsadaptedautomatically to engage saidratchet to 'uallyfcontrolling stops, thefrelationV of the continuously driven element and said mem i5 v e movement 'ofthe member.

ber-'being such that two revolutions'of the element are necessary to compel one complete l0. lThe combination'y with 1ar'trimrn'eiv' saw mounted vfor bodily movementrinto and out an operative plane,- ot means Viter lmoving the saw,said means including a positively and continuously,vr driven element" formed with a ratchet,' a member mounted for travel 1nV an endlessp ath, a connection between saidmemf berand the saw, pawlslcairiedby said mem-1;

b'er,'^said pawls automatically operated to in Y terconnect said member fand 'the' ratchet t0 thereby positively drive the member, means operative to disconnectftlie pawls from the f3.5 f Iconnecting meansafndthereby automatically disconnectthe pavvls and ratchet, and manratchet to thereby free the member Yfrom'said .ontmuously driven element, a'stop arranged "in the'path of movement'otl the disconnecting means to operate the latter, to disconnect the pawl's frointheratchet, a second stop inthe path of movement of the disconnecting means also'to interrupt the' movement of the disually Y operable mean-s vwhereby the positions ofthe stops with respect to the pathgot move-V ment of the disconnecting means maybe de- .'termined, the relation of the member and elel ment beingV suchvthat approXimatelv` two vrevolutions 'of the'element are necessary to 'compel' acoinplete movement of the member. fll. Autoniaticmanually*operative mechv and manually I operative means for position- Y' ing saidstops, the relation ofthe gearl and chain being'such 'that atleast two revolutions Y of the gearV are necessary to move thefchainf throughvr one `complete circuit, :coopefra'tive"V 'means provided onvlthe chain'and'one of said lstops adapted to move the latter into inactive position during one phaseofacticn of said member. y 1

lf2.` An automatic manually operative means for lowering and raising 'a trimmer saw i relative to an operative saw planef,1in'cluding a continuouslydriven gear formed withalV ratchet, spacedpinion's, one of which isfar-` rangedcoaxial with the geen-an endlessvchain carried by v said pinions, *a member movable with one o-thepinions, pa'wls carriedf'by the member, means .for autorn'a'ticallyr actuatingl thepa-wlsto engagethe same with the ratchetf i "851 for connectingthe chain and" gear "to causeV positive movement 'ofthe'c'hain byl the gear,

means connecting the chain tothe/saw, means carried by thememberand operativetoy dis-f engage the ypawls from thejratchetanddis- 9o Y vmally interposed! in the pathptmoVement t connect the chainfrom thefgear, a stop norofthe disconnecting means and operative to `cause'the disengagementpf the pawls frein the ratchet', manual vmeans' for' controlling theposition of said stop, and av secondstfop adaptedto vbev automatically interposed in the path of movement of the disconiiectingfmeansV todisen'gage the pawls from the ratchet, the

Y second stop being'automatically'Ypositioned ,inthe manual control ofthel first mentioned stop, the relation of' the, vchain vand gear,` be- Agear causes a movement of thechain substantiallyequal to one-half its complete'cirv` cuitof travel, cooperative means provided on the chain and onefoffsaid stops adapted to move thelatter Vinto inactive: position during onefphase of action of said member.

' e GEORGE"vDORMAN.,-"

. frariism for klowering' rand raising af trimmer sawinto andput of opera-tivev position, 1n'

Ycludingffay continuously driven gear gformed Q witha ratchet, an endless chain supported :for movement in a liXed path, means carried f by the" chainifor connecting the'saw rto the 'liso "chain," a .meinber moving'with the chain,

pawls carried by said'kmembe'r, meansada'ptf I Ved'` automatically to operate theVv pawls to engage theratch'et and thusv cause va positive movement of the vchain withsaid gear,a discpnnectingfelement carried by said member aiidopeiatd to release the PRWlS'm the disconnecting elementtol operatet-he latter to disconnect'thefpawlsroni lthe ratchet and@ 'hereby 'disconnect fthe" vchain fromthe gear,

" ratchet, a stop arranged inthe path ofl move- 1 mentl of the disconnecting velement "cooperatev the latter and thereby' disconnect the chain 2f-iointhe gear, a'second `Stop inthe path ofthe ico ing such that eachgcom'plete rotation olf the

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