US2271791A - Earth moving equipment - Google Patents

Description

Filed Oct. 23, 1939 7 Sheets-Sheet 1 f Re m0 n N N f m,/a n a d A n mm .Q QB rflw mi@ i. m i E- l E @i g a Feb. 3, 1942. 5` QLARK EARTH MOVING EQUIPMENT 7 Sheets-Sheet 2 Filed Oct. 23, 1939 n u oh. v .Il T6 E m m-H.|IH m/.Wm v O mM n A m S 2V m S w f m w Feb. 3, 1942. G. l. CLARK 2,271,791

EARTH MOVING EQUIPMENT ATTORNEY Feb. 3, 1942. G. l. CLARK EARTH MOVING EQUIPMENT Filed Oct. 23. 1939 7 Sheets-Sheet 4 INVEN-ron era/d C'lrk WM, E" ISYEZL/ -AfrroRNEY Feb. 3, 1942. Y e. l. CLARK 2,271,791

EARTH MOVING EQUIPMENT Filed'Oot. 23, 1959 7 Sheets-Sheet 5 ATTORNEY Febo 3 G' l. BARTH MOVING EQUIPMENT Filed Oct. 25. 1939 '7 Sheets-Sheet 6 IDI. MHH-hw Ns Q \\&T\\ R m mmm, N E E x S Ari-oRNEY Feb.f3, 1942. G. l. CLARK BARTH uovIue-Eourusnr Filed out. 23. 19:59

'I Sheets-Sheet 7 Oa Y ma. u 2m m y Patented Feb. 3, 1942 EARTH MOVING EQUIPMENT Gerald l. clark, Mountain view, cam., as-

signor to Wooldridge Manufacturing Company,

Sunnyvale, Calif., a corporation of Nevada Application october z3, 1939. serial No. 300,129

(ci. ca -12s) Claims.

This invention relates generally to earth moving equipment of the type utilizing an earth cutting or scraping blade, together with a bowl or like structure for receiving and carrying a load to a point of discharge. More particularly, the invention relates'to earth moving equipment making use of both a main bowl structure and an auxiliary bowl or front apron, with provision for raising the front apron and for adjusting the cutting blade during a loading operation, for closing the front apron to facilitate carrying the load, and for discharging the load from both the front apron and the main bowl.

An object of the present invention is to provide improved equipment oi the above character, particularly with respect to affording more flexibility and latitude with respect to manipulation and control. In this connection the invention is characterized by a type of control whereby raising and lowering of the cutting blade and movements of the front apron can be better coordinated by an operator.

A further object of the invention is to provide earth moving equipment of the above character in which it is possible to discharge the main bowl independently of manipulation of the front apron.

A further object of the invention is to provide earth moving equipment capable of both slow and rapid load discharging operations. Y

Another object ofthe invention is fto provide earth moving equipment capable of compressing the material being loaded during a loading operation, whereby the total load may be increased.

Additional objects and features of the invention will appear from the following description in which the preferred embodiments have been set forth in detail in conjunction with the accompanying drawings.

Referring to the drawings` Figure 1 is a side elevational view showing earth moving apparatus incorporating the present invention;

Figure 2 is a plan view of the equipment shown in Figure 1;

Figure 3 is a side elevational view, in cross section, illustrating a suitable type of power takei oft for a tractor, for use in conjunction with the equipment;

Figure 4 is a plan view of the power take-on shown in Figure 3 Figure 5 is a detail, in end elevation, showing clutch and brake control elements for one of the drums;

drums ofthe power take-o, molmted in alignment and controlled from a single lever:

Figure 'l is a side. elevational view of earth moving equipment, incorporating the invention. but being a dierent embodiment from that shown in Figure 1; andy Figure 8 is a view similar to Figure '1, but showing a further embodiment of the invention.

Figure 9 is an enlarged cross sectionaldetail showing a modified construction for the power take-off.

Referring mst te Figures and 2, the equipment illustrated is of the type including a wheeled frame A carrying the main and auxiliary bowls B and C, and adapted to be drawn by a tractor D. The tractor has a so-called power take-oil' E, by means oi which certain parts of the equipment are operated.

While the details of the bowl structure may vary in practice, as illustrated it consists of reinforced side walls II having rear extensions I2 which connect with an axle for the rear supporting wheels i3. The frameA is in the form of a yoke with the extensions of the yoke having pivotal connection Il with the sides Il of the bowl. Near the forward end of the main bowl there is a cross connecting beam or strut I6 serving as a mounting for the earth cutting or scraping blade I'I. v

As a part of the main bowl structure, and for carrying out a discharge operation, the bottom and rear walls of the bowl are formed as a movable member I2, which has a hinged connection I9 with the cross strut IB. It will be evident that when the hinged member Il is swung upwardly and forwardly, it effectively causes the discharge of a load from the main bowl structure.

The auxiliary bowl structure C, or front apron,

includes the side walls 2| and bottom load sup- Y porting wall 22. For supporting this auxiliary bowl to enable it to move in a general vertical direction with respect to the cutting blade l1, it is rigidly attached to the side arms 2l, which in turn have pivotal connections 24 to the sides Il of the main bowl structure.

The main frame A has a swivel connection 26 with the front axle 21, and this axle in turn forms amounting for the front supporting wheels 2l. This axle is also attached to the draft bar 2l, which is adapted to be coupled to the tractor D.

While various types of motive means can be applied for raising and lowering the blade I1,

for raising and lowering the front apron C, and

Figure 6 is an end elevational view showing two 55 for swinging upwardly and forwardly the hinged member I8 of the main bowl structure. in the present preferred embodiment forces are applied to these parts by three cables I, 2 and'l. Cable I is connected to the main bowl structure so that upon pulling or playing out this cable, the sides of the bowl and also the cutting blade I1 are raised or lowered. Cable 2 connects with the front apron or auxiliary bowl C. Cable 3 connects with the hinged member I3.

Cable I is guided by the sheaves 3| and 32 which are carried by a suitable mounting supported on the forward part of frame A. From sheave 32 the cable extends to the drum 33, to which the cable is anchored and about which it is wrapped. Drum 33 is carried by a vertical shaft 34 upon the frame A of the machine, and mounted upon this drum 33 there is a smaller drum 33. Cable In is anchored to and wrapped about the smaller drum 33, and is looped through the sheave blocks 31 and 33,' and anchored at 33 to one of the sides |I of the main bowl structure. The sheave blocks 31 and 33 connect with the cables I, and these cables in turn are guided. by sheaves 4I and 42, and attached at 43 to the forward extensions 44 of the bowl sides I I. pair of sheaves 4| and 42 are mounted in suitable sheave enclosures or boxes 43, and these boxes are in turn secured to the main frame A. When cable I is pulled, drums 33 and 33 are rotated, and the winding up of cable I* on drum 33 applies forces equally to blocks 31 and 33 to pull cables Ih and thus raise the forward portion of the main bowl structure and the cutting blade I1. Playing out cable I -likewise results in a lowering o1' the cutting blade I1, with the cables being maintained taut because of the weight of the bowl structure.

4Cable 2 is guided over the sheaves 41 and 43, which are likewise carried on the forward part of the frame A. From sheave 43, cable 2 is guided over the sheave 43, which is carried upon the main frame of the machine immediately above the drums 33 and 33. From sheave 43, the cable 2 is guided over the sheave 3| which is carried by a mounting 52. Mounting 32 is in turn secured to a cross beam 53', which extends between the sides I I of the main bowl structure. From sheave 5I, the cable 2 is looped under the sheave 53, and is then provided with an anchorage 51 to the mounting 52. Mounting 33 for sheave 36 is carried by the. front apron or auxiliary bowl C. Pulling upon cable 2, therefore, swings apron C forwardly and upwardly while playing out of the cable permits the apron 'to drop back by gravity.

Cable 3 is guided by sheaves 53 and 63, likewise mounted upon the forward part of the machine irame'. From sheave 33. the cable extends over a sheave 32 carried by mounting 32, and is looped over a sheave 3,3 and provided withJ an anchorage 34 upon'the mounting 32. Sheave 33 is carried by mounting 33, which in turn is secured to the hinged member Il. Therefore pulling upon Vcable 3 swings the hinged member I3 upwardly and forwardly, while playing out of the cable permits this member to drop back to its normal position by gravity. Power take-off E is of the type provided with three separate winch drums 1|, 12 and 1,3 (see Figure 3) about which the cables l, 2 and 3, respectively are wrapped. Drums 1i and 12 are controlled by the lever 14, while the drum 13 is controlled by lever 13. Thesevlevers are in convenient position for use by an operator of the tractor. The mechanism associated with level-'1s 1s such that for one operatingpositin of this lever, power is applied to drum 13 to wind up its associated cable 3, while for another operating position the brake for this drum is released and the drum is permitted to unwind to play out cable 3. The mechanism associated with lever 14 is such that this lever has several operating positions. In one operating position, power is applied to rotate winch drum 1I, while for a second operating position the brake for this drum is released, and the drum permitted to unwind to play out cable I. For another operating position of lever 14, power is applied to rotate the upper drum 12, to wind up cable 2, while for a fourth operating position of lever 14, the brake for drum 12 is released and this drum is permitted to unwind to play out cable 2. In addition to the four operating positions just mentioned for lever 14,` this lever has one, and preferably two, additional op erating positions, in one of which power is applied to rotate drum 1 I While simultaneously ,the brake for drum 12 is released and this drum per mitted to unwind. The other additional operating position serves conversely to apply power to rotate drum 12, while the brake for drum 1| is released, and this drum permitted to unwind. The last two operating positions permit certain operations to be carried out simultaneously to afford better manipulation as will be presently explained.

Various mechanisms can be utilized' in the construction of the power take-oil' E, in order to afford the features described. above. A desirable type of power take-off is shown in Figures 3 to 6, inclusive. Briey, this power take-oil includes a housing 13, upon which the drums 1|, 12 and 13 are carried and which is adapted for attachment to a tractor. The housing carries a pair of vertical shafts 13 and 3l, which are ,iournaled by the roller bearing assemblies 32 and 33. The lower end of each shaft is keyed to a worm gear 34, and these gears are driven by the worm 33. This worm is in turn secured to a drive shaft which is driven by the tractor motor. Drum 1I is journaled upon shaft 13, as by means of roller bearing assemblies`31, and drum 12 is journaled upon shaft 13 above drum 1I. A sleeve 33 is secured to drum 1I and extends upwardly within drum 12 for a purpose to be presently explained. The journal for drum 12 includes the roller bearing assemblies 33 and :isle assembly 3| between the sleeve 33 and shaft The mechanism whereby movement of lever 14 causes desired operation to drums 1I and 12 includes in this instance an arrangement of clutches and releasable brakes. Thus above drum 12 a clutch cone 32 is splined upon shaft 13. Below the cone 32 there is a cone 33 which is connected to the sleevej38. Thus when cones 32 and 33 are in engagement. rotation of shaft 1I,

drives the sleeve 33 to rotate the lower drum 1|. Sleeve 33 is therefore a torque tube for transmitting torque to the lower drum 1I. .Above the cone l2 there is another cone 34 which is carried by the cylindrical shell 33. This shell is mounted upon the upper side of the drum 12, whereby this drum is driven when cones 32 and 34 are in engagement.

V Instead of having a xed mounting for cone 34,

it is desirable to provide for adjustment as shown in Fig. 3. In this instar. .e the cone 34 A is carried by an extension 34a., the upper end of which is threaded. Extension 34a nts within and this shaft ls iournaled in brackets mounted upon thesupporting member |43. A compressionl tated in counterclockwise direction from the position shown in Fi re 4, arm |52 is swung to the left 'and shaft |48 rotated to release the brake band |51. i

It will be apparent from the above that `lever 16 has two positions from an intermediate neutral position for operation of the clutching means. When swung horizontally from neutral 4position in one direction, power is applied to rotate drum 13, because of engagement of clutch cones |33 and |34. When swung in an opposite direction from neutral position, shaft |48 is rotated by engagement of cam portion |53 with arm |52, thereby releasing the brake band |31 and permitting unwinding movement of the drum.

Referring again to Figures l and 2, operation of the complete equipment can be explained as follows: It will be presumed that one starts with parts in the positions shown in these figures and' that the machine is being traversed over a ground surface from which earth is to be removed. One possible procedure is'to swing lever 14 to the left (operators left) whereby the drive is establishedto the top drum 12, to elevate the front apron C. Lever 14 is then moved back to neutral position, and when it is desired to take a cut, the cutting blade is lowered by swinging lever 14 downwardly. This releases the drum 1 thereby permitting cable l to be played out. While taking a cut, the height of the cutting blade I1 may be adjusted as desired by moving lever 14 to the left to drive drum 1|, or by moving it downwardly to release this drum. As an alternative to this procedure, the operator may initially move lever 14 both to the right and downwardly whereby drum 12 is driven to pull upon cable 2 and thus lift the front apron C to a suitable loading position, and whereby drum 1| is released to simultaneously play out cable Vand thereby lower the cutting blade l1. 4The latter manipulation can frequently be used to advantage with a 'saving in time.

The load distributes itself within both the main bowl structure B and the auxiliary bowl C, and as the size of the load reaches permissible capacity, -the operator swings lever 14 to his left to drive drum 1| and wind up cable I to elevate the cutting blade I1, and at the same time` lever 14 can be swung upwardly to release the drum 12 ,.and by playing cut cable 2 permit the front apron C to drop down to closed position. It will be evident that although the raising of the blade can be continuous, and can'be accompanied by simultaneous continuous closing movement of apron C, these movements are entirely under the control of the operator, and the blade I1 can .be raised intermittently' or in stages, and the front apron likewise lowered in stages, as the operator may desire. Also if desired the blade |1 may be raised continuously while the front apron is being lowered in stages,` or conversely, the apron C can be lowered continuously while, the blade is raised in stages. Raising of the blade |1 is continued until this blade together with the main bowl structure B and the front apron C are well clear of the ground surface. This is what can be termed carrying Position oi' the machine, and the load may now be conveyed to a point of discharge. f

After initially taking a load Vshort of maximum capacity, it is a simple matter for the operator to compact the load, after which the load may be increased. Thus after partially or entirely raising the blade |1 from the earth, and after closing of the front apron C, the operator may operate lever 18 to drive the drum 13 and pull upon cable 2. thus causing the hinged member IB to swing upwardly and forwardly to compact the load. and to re-distribute the center of gravity of the 'load in the directionv of the front apron. After compacting the load in this manner, drum 13 is released to permit hinged member IB to return to the normal position shown `in Figure l. after which the front apron C is again raised and the blade |1 lowered to take on a further load.

Assuming now that the load has been carried to a point of discharge, where i't isdesired to spread the load over a substantial area, the operator swings the lever 14 Afrom 'neutral position to the right, whereby the upper drum 12 is driven to raise the front apron C and discharge a portion of the load over the cutting blade |1. Apart from or simultaneously with this operation, lever 14 can be swung downwardly to release drum 1|, thus permitting the blade |1 to be adJusted to a position corresponding to the depth of the spread desired. At any time' during upward movement of the front apron C, or after the front apron has been moved to its upper limiting position, the operator moves lever 1li to drive drum 13, thus pulling upon cabley 3 to swing the hinged member I8 upwardly and forwardly. whereby all the material in the main bowl structure is discharged. It will be evident that these discharging operations can be regulated and carried `out in stages as desired, consistent with the depth of spread required and the type of material being handled. In instances where it is desired to discharge a load rapidly, lever 1B is operated to swing hinged member IB upwardly and forwardly, and simultaneously -lever 14 is swung to the right to drive drum 12,4

thereby causing the apron C to simultaneously swing upwardly. It will be evident that this procedure makes possible a rapid discharge of the load, a feature whichis not possible in earth moving equipment of the type making use of a single cable connected to both the front apron and the main bowl structure, and arranged to iirst elevate the front apron and to subsequentlydischarge the main bowl structure.

After a discharge operation, the operator can quickly return the parts to the normal position @gown in Figure 1, for taking on another load.

us lever 16.can be operated to permit the hinged bottom I8 to drop back to normal position, and simultaneously lever 14 can be swung upwai-diy and to the left to lower the cutting blade |1 and to place the apron C in proper'position for a cut. If desired, suitable spring-means can be employed to ald return of-member I8 to normal position.A

The embodiment of the invention illustrated diagrammatically in Figure 'I makes use of a sliding gate within the bowl structure in place of a hinged bottom I8. The main bowl structure IBI l has a fixed bottom |82 extending backwardly from the cutting blade |63. The gate |64 is mounted for sliding movement longitudinally of the bowl structure, and ls connected to the cable 3 from the drum 13. The front apron |86 is connected to arms |61, which in turn have pivotal connections |68 to the sides of the main bowl structure IBI. This apronis connected to cable 2 which extends from the drum 12. frame |69 is shown attached to the upper part of the bowl structure and serves as a mounting for the spring I1I. A cable |12 leading from this spring is guided over sheaves |13 and attached to theA sliding gate |64. This spring and cable connection serve the purpose of returning gate ISI to the initial position shown in Figure 7.

The forward frame |14 has rearwardly extending side members whlch are pivotally connected at points |16 with the sides of the main bowl structure. The main bowl structure is connectel to a rear axle carrying the wheels |11, while the front frame Illcarries the wheels |18. Cable I is guided over the stationary sheave |18 carried by the forward part of, frame |14, over sheaves |8| and |82, and anchored at |83 to the frame |14. Sheave |0| is carried by the frame |14, while sheave |82 is carried on one end of a beam |84, the other end of which has a pivotal connection |86 with the frame |69. Thus pulling upon cable I serves to raise the main bowl structure with respect to the ground surface.

Cable 2 is guided over sheaves |81 and IBB, carried by frame |14, and also over the sheave |89 carried by frame |69, and finally attached at I9! to the front apron |86. Cable 3 engages sheaves |92 and |93, which are carried by frame |16, and also by sheaves I 98 and |95, carried by the frame |89.

The embodiment of Figure '7 operates in substantially the same manner as the embodiment .first described. In place of swinging the hinged tvv upwardly and forzr .ly te discharge 'tructura a bidi upon cable 3 s gate ll forwardly to positively expel the Toad.

The embodiment of Figure 8 (Shown diagrammatic-ally) makes use of a main bowl structure which is tipped forwardly to discharge the load. Thus in this instance the machine includes a frame |31' carrying the forward and the rear wheels tilt and ISS. rEhe mein bowi structure fifi? has pivotal connections 13d? attached to the side frame si;

apr-on l :l con` .o members o," :hf sagt 55mgguided over sheaves "2M and. iii carby the for ward part of the frame im', and so is passed over sheave 2|? and carri-esi by t e bracket Elfi From sh M2 cable l is looped over shears 214 and pit L. ed with a fixed anchorage 216 to bracket 21d.l Sheave is carried by a mounting; 2V! which in turn is at tabbed lo cross member cmnecting the frame stumbles LS. Upon pulling cable I, the frame eres 253 are elevated about the pivotal cont 212i to raiseV the main bowl EBI and its forward cutting edge.

Cable 2 is guided over sheaves 2li! and 2|9 which are carried by the forward portion of fr me |91. Its upper end extends over sheave carried by mounting 2I1. u. connection 222 to the front apron 28E.

Cable 3 is guided over sheaves 223 and 22e which are also carried by frame I9?, and extends over sheave 226 for connection at 221 to the Its lower end has' of the main bowl structure 20|.

cable 3 causes the main bowl structure 20| to bet tipped upwardly and forwardly about the pivotal connections 202.

The embodiment of Figure 8 operates in substantially the same manner as the embodiments previously described. However, in place of a bowl structure having stationary sides, the entire bowl structure tips forwardly to discharge that portion of the loadwhich is within the main bowl structure and which is not discharged by elevating the front apron 202.

I claim: ,l

1. In earth moving equipment, Aa wheeled frame, a main bowl structure carried by the frame, said bowl structure including a forward earth cutting blade mounted for adjustment in a vertical direction, an auxiliary load carrying bowl or apron ln front of the main bowl and movable in a general vertical direction relative to the cutting blade, means under the control of a single operating lever for independently raising and lowering the cutting blade and raising and lowering the front apron, and means for discharging the main bowl structure.

2. In earth moving equipment, a wheeled frame, a main bowl structure carried by the frame, said bowl structure including a forward earth cutting blade mounted for adjustment in a vertical direction, an auxiliary load carrying bowl or apron. in front of the main bowl and movable in a general vertical direction relative to the cutting blade, means under the control of a single operating lever for independently raising and lowering the cutting blade and rais ing and lowering the front apron, and means under the control of a separate lever for discharging the main bowl structure.

3. In. earth moving apparatus, a wheeled frame, a main bowl structure carried by the frame, the bowl structure .baring an earth eutting blade near its forward end capable of adjustment in e vertical d ation. an auxiliary earth carrying bowl or front apron disposed in front of tbe main bowl structure and movable in a. gene 'il cal directioil with. :aspect to the power ineens raising and lowittng.; blade, fili. raising and lowering I r discharging the main for said newer winni opereied n.. the roam bowl Qontrol levfrs when tie front apron 27- l upper rear corner Thus a pull upon pron a..

Lw L,

us, a wheeled riore carried by the baring a forward gro x; wie ce i of adjustment in a vertical sinon, an ilary load 'c :Wing bowl or apron disposed in 'front of the man; btw] lfwnueture and movable in a gener-:7.1 vertical 'lltrection relative to inc cufing blade, a pair-of cables connected to thc cutting blade and to the front apron. whereby by pulling or playing out one cable the level of the cutting blade is adjusted, and by pulling' or playing out the other cable the il 'ci apron is raised or lowered, power means including a pair of winch drums upon which said cables are wound, and a snvle ccntrol lever for said winch drums whereby power can be applied to either winch drum for winding up its associated cable, or whereby either winch drum can permitted to unwind to play` out its associated cable.

5. In earth moving apparatus, a wheeled frame, a main bowl structure carried by the frame, the bowl structure including a forward earth cutting blade`mounted for adjustment in a vertical direction,f4 bowl or iront apron disposed in iront of the main bowl structure and capable of movement in a vertical direction relative to the cutting blade,ra pair of cables having connections to the cutting blade and to the front apron whereby when one of the cables is pulled or played out the cutting blade is raised or lowered, and whereby when the second cable is pulled or played out the front apron is raised or lowered, power means including a pair of winch drums upon which said cables are wound, and means including a single control lever for controlling winding or unwinding rotation of said winch drums, whereby by operation of said lever either of said drums may be rotated to wind up its associated cable or permitted to rotate in an opposite direction to play out its associated cable, or whereby either drum may be rotated to wind up its associated cable while simultaneously the other drum is permitted to rotate to play out its associated cable.

6. In earth moving apparatus, a wheele'i frame, a main bowl structure carried by the frame, the bowl structure having a forward cutting blade mounted for adjustment in a vertical direction, whereby the depth of a cut can be varied and whereby the cutting blade can be elevated to a carrying position or for leveling operations, an auxiliary load carrying bowl or apron disposed in front of the main bowl and mounted for movement in a vertical direction relative to the cutting blade, whereby the front bowl can be raised relative to the cutting edge during the taking on of a load, lowered to carry a portion of the load, and raised to discharge a portion of the load over the cutting blade, at least three operating cables, one cable being connected to the cutting blade and serving totraise and lower the cutting blade when the cable is pulled or played out, a second cable being connected to the front apron and serving to raise or lower the front apron when the cable is pulled or played out, and a third cable being connected to the main bowl structure whereby the main bowl structure is discharged when its associated cable is pulled, and power means for operating said cables, said power means including three winch drums upon which said cables are individually wound and `two control levers for effecting operation of said three winch drums, one of said control levers serving to elect winding or unwindins movement oi the winch drum connected to an auxiliary load .carrying the main bowl structure, whereby the main bowl structure may be discharged, and the other control lever having a plurality of operating positions whereby either of the drums connected to the scoppi and third cables may be rotated to wind up itssiociated cable or permitted to unwind to play o t its associated cable.

'7. In earth moving equipment, a wheeled frame, a main load carrying bowl structure carried by the trame, the bowl structurehaving a forward ground cutting blade capable of adjustment in a vertical direction and also including a member movable for the purpose of discharging earth in the main bowl structure over the cutting edge, an auxiliary load carrying bowl or apron disposed in front of the main bowl structure and movable in a vertical direction relative to the cutting blade, power means for eflecting either raising and lowering of the cutting blade or raising and lowering of the front apronindependently of the cutting blade, a single operating lever for controlling said last named power means to cause the same to either raise or lower the cutting blade or to raise or lower the front apron independently of the cutting blade, and

additional power means for effecting operation of said movable member.

il.` In earth moving equipment, a wheeled frame, a main load carrying bowl structure carried by the frame, the bowl structure having a forward ground cutting blade capable of adiustment in a vertical direction and also including a member movable for the purpose of discharging earth in the main bowl structure over the cutting edge, an auxiliary load carrying bowl or apron disposed in front of the main bowl structure and movable in a vertical direction relative to the cutting blade, three operating cables each adapted to be pulled or played out, the first cable being connected to raise or lower the cutting blade, the second cable being con nected to the front apron to raise or lower the same, and the third cable being connected to said movable member, three winch drums upon which said cables are individually wound, and means including a pair of control levers for selectively and independently controlling the operation of said winch drums, one of said control levers controlling winding or unwinding movement, of the drum with which the third cable is associated, the second lever serving to control winding or unwinding movement of either one of the winch drums with which the first and second cables are associated.

GERALD I. CLARK.

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