US2380285A - Excavator - Google Patents

Description

E. W. AUSTIN July 10, 1945.

' EXCAVATOR 7 Sheets-Sheet 1 Filed Oct 7, 1941 INVENTOR [7/5 war/72 W Hus/#7 Ill y E. w. AUSTIN 2,380,285

" EXCAVATOR Filed Oct. 7, 1941 7 Sheets-Sheet 3 w w /I/ INVENTOR July 10, 1945. E; w AUSTIN EXCAVATOR Filed Oct. 7, 1941 7 Sheets-Sheet 4 ymqggw July 10, 1945. E. w. AUSTIN EXCAVATOR Filed Oct. 7. 1941 7 Sheets-Sheet 5 July 10, 1945. E. w. AUSTIN EXCAVATOR 7 Sheets-Sheet 6 y 10, 1945- .E. w. AUSTIN 2,380,285

EXCAVATOR Filed Oct. 7, 1941 7 Sheets-Sheet V INVENTOR 1514/0/79? f/40524.

Patented July 10, 1945 EXCAVATOR Ellsworth. W. Austin, Cedar Rapids, Iowa, assignmto La Plant-Choate Mfg. 00., Inc.,

Cedar Rapids, Iowa, a corporation of'Del'aware Application October 7, 1941,. Serial No. 413,930

8 Claims.

My invention relatesto earth and material digging andhandling machinery and is concerned with the type of machine disclosed generally in my Patent No. 2,329,448; In such apparatus there is provided a drawn vehicle intended to be propelled by an attached tractor and including a main earth-containing bowl, the forward por--- tion of which is closed by a front apron for retaming earth and the rear portion or which is closedby a. pusher forming the rear wall. When the contained material is to be discharged, cable mechanism attached to the pusheris tautened and the pusher is advanced through the bowl at the same time that the front apron is swung upwardly to open the front end of the bowl. One of the characteristics of such mechanism is that the pusher andthe front apron have no mutually independent movement, but are connected together by means such as a link pivoted at its opposite ends to the pusher and frontapron respectively. The material being handled is usually slightly compressible, but not to a great extent, although whatever compression of the material isaecomplished requires substantial power. With the pusher and front apron directly linked together it is always a problem to provide a substantial apron opening to afford room for expelling the material before the pusherhas accomplished somueh of its forwardtravel as to result in serious compression.

It is therefore an object of my invention to provide an excavator in which the linkage between the pusher and front apron affords advantageous mutual movement of the pusher and front apron. r

Another object of my invention is to provide a linkage betweenthe pusher and front apron Y which affords opportunity for considerable variation in layout and flexibility in design.

Another object of my invention is to provide an excavator-inwhlch theactuating force for the v pusher and front apron is advantageously applied.

Another object of=my invention is to provide an excavator which'in general is an improvement over excavators heretofore known.

The foregoing and other objects are attained inthe embodiment of the invention illustrated in the drawings in which- Fig. 1 is a plan of one form of excavator constructed in accordance with my invention, the forwardportion of the mechanism being broken away to reduce the size of the figure.

Fig. 2 is a cross-section on the line 2 -2 of Fig. l which is in the central longitudinalvertical plane.

Fig. 3 is a detailed cross-section. the plane of which is indicated bythe line 3-3 of Fig. 2.

Fig. i is a detailed cross-section the plane of which is indicated by the line 4-4 of Fig. 3".

Fig. 5 is a plan similar to Fig. l but showing a modified form of excavator in accordance with my invention.

Fig. 6 is across-section On a central vertical longitudinal plane as indicated by the line 6--G of Fig. 5 through the modified.- form of excavator.

Fig. 7 is a detailed cross-section the plane of which is indicated by the line |"--l of Fig. 6.

Fig. 8 is a cross-section theplanes of which are indicated by the lines 8-8 of Fig. 6.

Fig. 9 is a diagram in isometric perspective showing the cable arrangement of the modified form of excavator in Figs. 5 to 8 inclusive;

Fig. 10' is a side elevation of a furthermodified form of excavator in accordance with my invention, a portion being broken awayto disclose the interior construction.

Fig. 11 is a plan of the further modified form of excavator disclosedin Fig. 10.

t Fig. 12 is a detailed cross-section the plane of which is indicated by the line l2l2'of Fig. 11.

In its preferred form the excavator of my invention includes a main frame having a main bowl incorporated therewith and a front apron mounted to swing from a position closing the front of said main bowl into another position opening the front of said bowl, as well as a pusher incorporating a transverse wall in one position closing the rear end of said main bowl and being designed to move through the main bowl. A rocker mounted on the frame and provided with an actuating mechanism isconnected to the front apron and to the pusher in order to move the front apron and pusher simultaneously from their closed and rearward positions respectively, into their open, and forward positions respectively.

In the first form of my invention disclosed herein, as illustrated in Figs. 1 to 4 inclusive, there is provided a frame, generally designated 6. This frame has a front yoke portion (not shown but disclosed in my application aboveidentified') which extends rearwardly by means of a pair of side beams I and 8 respectively. The side beams terminate at their rearward ends in aligned 'pivot bearings 9 and II respectively, which are journalled on side walls I! and i3 respectively of a main bowl, generally designated M. The sides 12 and I3 are united with a bottom plate I6 so that'in effect the main bowl is a trough-like structure open at its forward end and open at its rearward end.

The forward end of the bottom I6 is merged with a cutting edge I! for dislodging material being excavated, and the rearward portion of the walls I2 and I3 and of the bottom I6 is secured to a number of frame members I8 and H which connect with a rear axle 2| at the ex tremities of which ground-engaging wheels 22 and 23 are mounted. The main frame 6 therefore includes not only the members I and 8 and all of the yoke frame which at its forward end is mounted on ground-engaging wheels, (not shown), but likewise includes the main bowl l4 and its connections to the rear wheels 22 and. 23. Hence the main bowl has two capacities; namely, that of a frame portion and that of an earth confining portion. sider that the frame includes the main bowl as one of its components.

As more fully disclosed in my application above mentioned, the members I and 8 are made relatively movable with respect to the main bow I4 in order that the cutting edge I! can be raised and lowered. This motion is accomplishedprimarily by lifting cables 23 extending to a suit able hoist mechanism (not shown) and fastened to bell cranks 24, themselves connected by pivots 26 to the forwardly extending portions of the side walls I2 and I3, and normally urged rearwardly against suitable stops 21. By appropriately manipulating the cables 23 the cutting edge I! is lowered to an excavating position, raised partially to a leveling or low carrying position, or raised a maximum amount into a high carrying position.

Adapted to close the rear end of the main bowl I4, is an earth pusher, generally designated 28-, constituted primarily by a. transversely extending wall plate 29 providedwith, reinforcements 3| and at its opposite ends merging with carriage structures 32 and 33 respectively. These carriages are substantially symmetrical so that It is correctto con-.

the description of oneof-them applies to both.

Included in each carriage is a side plate 34 slightly spaced from but parallel to the adjacent side wall l2, forexample, at its rearward end fastened as by welding to the pusher wall 29. Along its forward edge the side plate 34 is beveled as 'allel to itself and does not tend to twist about a central vertical axis nor to run unduly to one side or the other, the side plate 34 is provided with a pair of rollers 41 and 48 respectively which are arranged to run on vertical shafts 49 mounted within shrouds 5| to protect against earth. The rollers 41 and ,48, engage the side walls l2 directly to limit the transverse freedom or side play of the pusher 28.

To advance the pusher from its-rearmost position, as shown in Fig. 2 in full lines, to its forward position, as shown in broken lines in that figure, any suitable propulsion mechanism is afforded, in this instance a cable scheme being utilized. While the cables are not illustrated herein in detail since they are shown in my above-mentioned patent, their operation is clearly discernible from the provision on the brackets 42 of the sheave block 52 which assists in supporting the shaft 53 on which a pair of sheaves 54 and 56 are freely mounted. These sheaves are in substantial alignment with a pair of sheaves 51 and 58 mounted'between a bracket 59 and the side wall |2. A cable reeved over the respective sheaves when tautened is effective to advance-the pusher 28 andwhen slackened permitsthepusher 28 to return in a rearward direction. With this arrangement by appropriately manipulating cables engaged with thelrespective sheaves, the pusher 28 can be advanced and retracted throughout its travel in the main bowl M, the pusher being adequately guided by the carriage structure.

Somewhat to increase the earth retaining capacity of the mainbowl I4, I provide on each side an additional side wall 6| preferably constituted of a structural shape. At its forward end the wall6| is secured to the forward portion of the upstanding sidewall I2, for example, and at its rearward endit is connected by a bracket 62 to a crossbeam 63 bracing the rearward portions of theside'walls I2 and I3. In effect, the additional side walls 6| are substantially coplanar with, the side walls ,I2 and I3. Each affords an elongated aperture 64 within which the rollers 39 and associated carriage structure have free motion. Since the aperture 64. is substantially closed against escape of eanth by the upstanding plate 34 of the carriage, the capacity of the main bowl is increased considerably overwhat it would be if the side wall 12 terminated-adjacent the rail 4 vIn effec t,-a very high side wall is afforded with the pusher carriage operating through an aperture in the wall, yet with the aperture shielded by the carriage against escape of earth.

In accordance with-my invention I preferably close the front of the main bowl M by a front pusher, the plate 34 is provided with a bracket 42 which extends over the top of the side wall l2 and depends on the outside thereof to carry a stub shaft 43 on which a roller 44 is mounted. This roller runs beneath the rail 4| but on top of a rail 46 secured to the side wall l2, so that not only is some of the weight of the pusher appropriately borne, but also in the event of accidental dislodgem'ent of the pusher it cannot rise more than the slight clearance between the roller 44 and the top rail 4|. The weight of the pusher is'very substantial and there is little likelihood of any rising motion, but it is advisable to provide the arrangement shown in order that the pusher can be confined to a substantially true rectilinear path of translation.

To take care that the pusher runs always parapron, generally designated 66. This member is comprised of a transversely extending curved plate 6'! suitably reinforced by structural shapes 68 and at its opposite ends is secured preferably by welding to front apron side arms 69 and II respectively. These apron arms are approxi-, mately crescentshaped plates and extend just inside the sidewalls l2 and I3 when the front apron is in its closed position. In such position the lower end 12 of the apron is in approximate abutment with the cutting edge I'I. Appropriately to mount the front apron, the side arms 69 and 'Il extend rearwardly to pivots 13 and 14 which are mounted on theside wall extensions 60 and 6|. By this mounting the front apron 66 is free to'swing in an are about the aligned pivots 13 and 15 as an axis from the full lined position, as shown in Fig. 2, into the broken line position therein illustrated. From its: upper position the front apron can return to itsclosed position under theforce of gravity and this force is utilized to assist in restoring the rearmost position. I

In order appropriately to join the frontapron 66 and the pusher 28 for conjoint motion, yet in a fashion which will afford substantial front apron opening before there has been a great deal of pusher advancement, and to afford considerable freedom and choice in design, 1 preferably mount on the crossbeam 63 supports '16 for the reception of pivot shafts I1 and 18 on which symmetrical mechanisms are mounted. A description of one of these mechanismsapplies to both. A rocker I9 is journalled on the shaft 11 for example, and has two arms 61 and 82 respectively. The arm 62 extends generally rearwardly and is connected by a pivot 83 to a link 64 serving as means for connecting the rocker to the pusher 261 This is effected by a pivot 86 at the forward end of the link 84 which also engages a plate 81 extending from the pusher 28.

The arm 8| is provided with a pair of apertures 69 into one of which extends a pin 9| connected to a universal joint 92. A forwardly extending link 93 is fastened to the universal joint 92 by a pivot pin 94 and is similarly connected by a pivot pin 96 to a universal joint 91' joined by a pivot pin 98 to a bracket 99upstanding fromthe side arm 69 of the front apron 66.. p v

Withthis arrangement, when the cables engaging the sheaves 54, 56, and 51, 58 are tightened, the pusher 28 is drawn forwardly, the force is transmitted through the plate 61 and the links 84 to the rockers 19, the arms 8| of which draw upon the links 93 so that the brackets 99 are effective to lift the front apron 66. The pivot points for the rockers and the relative disposition of the links 64 and 93 is such that the desired mutual motions of the pusher 2B and of the front apron are afforded. Thus, the front apron moves from its closed osition into its open position as the pusher moves from its rearmost position into its foremost position. On the return motion the weight of the front apron 66' is effective to draw upon the link 93, to assistin rotatingthe rocker 19 todraw upon the link '84 and thus to retract the pusher 28. In addition to this gravital return, a return cable can be securedto the pusher 28 as disclosed in my aboveidentified' application.

can be varied. 'If the aperture not utilized in L Fig. 1 is connected with the pin 9| the principal change is a lesser total travel of thefront apron 66. Although the closed position remains the same, the open positionis somewhat lower. With this arrangement, therefore, mechanical advantages and numerous variable leverages to produce the desired motions can readily be afforded, yet the mechanism is well out of the area occupied by earth in the main bowl.

In the modified form'of my excavator shown in Figs. to Qinclusive, the general arrangement is' approximately the same with a main frame, generally designated IOI, including a main bowl I02 having side walls I03 and I04; Within the main bowl is a pusher, generally designated I06, which is constituted primarily by'a transverse wall plate I01 turned at the opposite ends for additional rigidity. The ends of the wall are not connected by any carriage structure, a carriage being entirely omitted inthis instance.

pusher '26 to its The principal weight or load-on the pusher I06 is borne by a pair. of pneumatic tired wheels I08 secured in suitable brackets I09 extending rearwardly from thepusher I06 and designed to engage the bottom wall III of the main bowl I02.

' The links are mounted in mutually inverted relationship, so that the parts can be duplicated on opposite sides of the machine. The forward end ofthe link H6 is bifurcated to form a pair ofbearings II1 receiving a pivot bearing shaft II8 mounted in brackets II9 secured on the pusher I06.

The rearward ortion of the link'II6 isconnected by a pivot pin I2I to one arm I22 of a rocker, generally designated I23. The arm I22 at its hub is bifurcated to provide a pair of bosses I24 secured to a pivot shaft I26. This shaft at its lower end is journalled in a hub I21 mounted on a bracket I28 supported on frame members I29, while at its upper end the shaft I 26 turns in a journal I3I supported in a bracket I32 fastened to a crossbeam I33 extending between the side walls I03 and I04. Rotation of the shaft I26 produces comparable rotation of the arm I22.

Included with the arm I22 and the shaft I26 in the rocker I23 is an arm plate I34 of generally triangular shape which is fast on the top ofthe shaft I26. U-pstanding from the plate I34 is a pin I31 forming part of a universaljoint I38, the other pin I39 of which is secured to the rear of a link I4I extending forwardly. This linkis preferably braced in the central portion to preclude whipping and vibration which might other-. wise be present due to its length.

At' its forward end the link MI is connected by a pivot pin I42. to a universal joint I43 joined by a pin I44 to the side arm I46 of a front apron, generally designated I41. The side arm I46 is connected by a pivot pin I48 to the side wall. I03 and a comparable side arm I49 included in the front apron I41, is similarly connected to the side Wall I04. The side arms I46 and I49 are preferably of double wall construction straddling the side walls I03 and I04 respectively and carry abutment stops I5I engaging similar abutments I52 on the upper edge of the respective side walls in order that the front apron can be limited in its lowering motion to avoid heavy impact of the trailing edger-i3 of the front apron I41 against the cutting edge I64 of the bowl bottomIII.

In order to move the pusher I06 and the front apron I41 I preferably apply force notto the pusher I06 which is relatively slow moving in its initial travel and hence affords a relatively poor mechanical advantage, but rather applythe actuating force to the rockers I23. Each of the triangular levers I34 carries a stub shaft I6I on which a plurality of sheaves I62 are separately journalled. To reinforce the shaft I6I as well as the pin I31, I join. the. pin and shaft atltheir upper end by a tiestrap I63 connected by a fas-. toning bracket I64 to the plate I34. An. operating cable I66 is connected by a fastenihgllil to one of the plates I34, is then reeved successively about the various sheaves I62, and extends to a corner sheave I68 mounted on a bracket HES- on the crossbeam I33. Then the cable I66. extends forwardly around a guide sheave I'll and 'to a suitable cable actuating device; Tension on the cable I66 causes the various sheaves I62 on one of the rockers I23 to tehd to approach the corresponding sheaves on the other of the rockers. The relatively approaching movement is the same for both of the rockers sinc they are constrained to equivalent motion through the medium of the links I4I both of which connect to the front apron I41, itself a substantially rigid structurev acting as a crosstie. Thus, the rockers I23 both rotate in unison and the links I22 rotate in opposite directions on their respective shafts, but in strict unison. links II6 are advanced simultaneously and the pivot pins I I8 on the pusher I06 always move substantially in the same transverse plane.

Because of the presence of the four pivots I I and I2I, however, there is a possibility of transverse movement of the pusher plate I01, and if the side walls I03 and I04 were not present the pusher plate could havea very material transverse movement. However, th rubber wheels II2 bearing against the side walls respectively, serve to limit the transverse movement permitted by the connections between the pusher and the rockers I23. With this arrangement, therefore, it is not necessary to have any guide carriage, but the main bowl side walls and bottom are utilized for that purpose.

The pusher is moved by application of force to the rockers I23 from its full line position, as shown in Fig. 6, at the same time that the front apron is being moved from its full line position in that figure. When the parts areto b restored the weight of the front apron can be counted upon to provide all or a major portion of the restoring force exerting tension through the links I4I, the rockers I23 and the arms I22 and links II6 to retractthe pusher I06. In addition, there is provided a retracting, cable I16 connected by a fastening I11 to the rear of the pusher I06 and extending around a sheave I18 mounted on the crossbeam I33. The cable I16 passes around a corner sheave I19 mounted on the bracket I69 and extends thence forwardly around a guide sheave I6I and to any appropriate cable handling mechanism. With this arrangement, the pusher and front apron partake of the desired mutual movement and because of the interposition of'the rockers I 23, th selection of lever arm lengths and pivot point positions affords a wide range to the designer in the relative motions of these parts. In addition, the imposition of force on the rockers rather than on the other elements permits the stress of the cables to be lessened and the omission of the carriage structure.

A further modified form of my excavator is disclosed in Figs. '10, 11 and 12 and includes substantially the same general arrangement. The main frame 20I includes a front yoke frame 202 having side beams 203 and 204 respectively, and includes also a main bowl, generally designated 206, which is provided with side walls 201 and 208 joined by a bottom wall 209. at its rear end terminates in frame portions 2I I joined to a rear axle 2I2 at the extremities of which ground-engaging wheels 2I3 are located. At the forward end of the main bowl bottom 209 is a cutting edge 2I6 and in order to raise and lower the cutting edge with respect to the ground the rear portion of the main frame 20I is moved with respect to the front portion 202 about the axis of pivotal connections 2I1 by a cable structure.

To the side walls 201 (Fig. 12) is pivoted a cable The The main bowl anchor 2I8securing one end of a heav cable 2I9. This cable extends through a suitable .aperture and around a sheave 22I journalled in the side beam 203. Thence, the cable extends around an equalizing sheave 222 and around agulde sheave 223 mounted on an upstanding bracket 224 on the side arm 203. Then the heavy cable 2I9 is turned around a corner sheave 226 upstanding from the frame 202, extends across to and around a corner sheave 221, then over a guide sheave 228 journalled in the side beam 204 and finally downward to an anchor 229 connected by a pivot to the side wall 204. With this arrangement, movement of the sheave 222 exerts equal lifting force on both of the side walls 201 and 208.

The equalizin sheave 222 is mounted in a yoke 23I which straddles a plurality of sheaves 232 journalled on the same shaft 233 as the yoke at the upper end of a guide lever 234. Thi lever'at its lower end passes through a suitableaperture in the side beam 203 and is connected by a pivot pin 236 to brackets 231 depending from th side beam 203. A plurality of aligned sheaves 236 are journalled in upstanding brackets 239 at the end of the side beam- 203. A light actuating cable 24I is anchored at an appropriate spot, is trained around the various sheaves 232 and 238 and extends thence around a corner sheav 242 and a central sheave 243 both upstanding from supports on the frameportion 202, and is controlled by a suitable mechanism (not shown). When the cable 24I is tensioned, the lever 243 is rocked toward the left, as seen in Fig. 12, and the cutting edge 2I6 is raised. When the light cable 24I is slacked the lever 234 rotates toward the right, as seen iIrFig. 12, and the cutting edge 2I6 lowers by gravity.

Adapted in one position to close the rear end of the main bowl 206 is a pusher, generally designated 246, which is partially constituted by a transversely extending pusher wall 241. Substantially in the general plane of the wall 241 are the axes of a pair of pneumatic wheels 248, with each of which is associated a metal wheel P 249 of lesser diameter, effective only in the event the bottom wall 209 of the main bowl, so that in.

efiect the forward portion of the shroud acts as a scraper to maintain a relatively clear path for the wheel 248. Transverse motion of the pusher is limited to a very minor amount by lateral pneumatic wheels 253 adjacent the side walls 201 and 208 respectively. The wheels 253 are provided with metal wheels 254 effective only on the event the pneumatic-wheels become seriously deflated and are journalled in suitable brackets 255 extending from the pusher.

Extending rearwardly from the pusher wall is a connecting brace 256 in the form of a stiffening box which merges with the construction of the pusher, and at its rearward end carries a pivot pin 251 with which is rather loosely hinged a lever 2-58 of box construction and fast on a transverse shaft 259. The loose connection between the connector 256 and the lever 256 permits a slight transverse movement of the pusher as restrained by the pneumatic wheels 254. The effect is to permit some slight transverse motion of the pusher but in general to keep it guided in its path by the sidewalls of the main bowl.

erably applied directly to the rocker. purpose one end of the shaft 259 is provided with Thelever 258 and the shaft 259 areconstrained toarotary motion by a plurality ofbearings 282 mounted in ,brackets 283r extending from; ,a crossbeam 264; joined at its opposite GHdSytaO the side wallsifl'lu and 20Brespectively. Atqthe opp site ends oftheshaft 259 and included, with the shaft and the lever 258 to constitute a rocker mechanism, \are-identica1 arm 12-65 and 26B respectively. Since the structure at this point is identical on both sides of the machine, the description of one applies to both. The arm 265 at its lower end is bifurcated to receive a pin 2'61 affording a pivotal connection to the rear end of a link 268 which extends forwardly between the spaced plates 269 and 21I of the double side wall 208 of the main bowl and at its forward end the link 268 is connected by a pivot pin 212 to the lower end of a lever 213 fast on a stub shaft 214 journalled in the Plates 269 and 21! and projecting outwardly from opposite sides thereof.

On the opposite end of the stub shaft 214 extend the dual side plates of one of the two arms 218 and 211 of the front apron generally designated 218. The major portion of the front apron is constituted of a plurality of curved plates 219 extending transversely of the main bowl. Since the arms 216 and 211 are fast to their respective stub shafts 214 onto which the levers 213 are likewise fast, the front apron 218 and the pusher 246 are connected together by linkage so that they partake of amutual movement.

To produce the movement, the force is pref- For this a grooved quadrant 28I which is fast on the shaft so that they turn in unison. Connected by a cable anchor 282 to the quadrant 28 I, is a heavy cable 283 lying within the quadrant groove and extending to a yoke 284, straddling a pin 286 at the upper end of a guide lever 281 which passes through the side beam 204 and is mounted by a pivot pin 288 within brackets 289 extending from such side beam. The pin 286 likewise serves as a mounting for a plurality of sheaves 29! in substantial alignment with a similar plurality of sheaves 292 mounted in a bracket 293 upstanding from the side beam 204. A light cable 294, suitably anchored, is reeved around the various sheaves 29| and 292, extends thence forwardly around a corner sheave 29B and around a center sheave 291, the latter of which are mounted in suitable brackets on the yoke frame 20!, and finally to a suitably controlled cable operator (not shown).

With this arrangement operation of the cables 294 is effective to cause the sheaves 29I and 292 to approach each other, thereby drawing upon the heavy cable 283, rotating the rocker and impelling the pusher to advance and at the same time through the links 268 swinging thefront apron 218 from its closed position to its open position. The return movement is accomplished primarily by gravity due to the weight of the front apron, but if desired, there can be provided a retractingcable as shown in a previous are -ver-y advantageously related. This is espea ly p ar n b an e am a io o i in whichit is shown gtl iatv the pusher in its inter-,- nrediate position-has advanced at the bottom portion farmore tharjrat thel op portion. Since the et r rtion 9f the l ad i f e t ar e ooner a that o t ap n ri es h le e upper portion/is still somewhat confined, this linkage reduces the compression of the load and is well means extending longitudinally of said frame for connecting said rocker to said pusher.

2. An excavator comprising a frame including a main bowl, .a front apron mounted to swing in a vertical arc to open and close one end of said bowl, an earth pusher adapted to close the other end of and to move through said main bowl, a rocker pivotally mounted on said frame to swing in a horizontal arc, a, link connected by universal 'joints to said rocker and to said front apron, and means for connecting said rocker to said pusher.

3. An excavator comprising a,frame including a main bowl, a front apron mounted to swing in a vertical arc to open and close one end of said bowl, an earth pusher adapted to close the other end of and to move through said main bowl, a pair of rockers pivoted on said frame to swing in horizontal arcs, a pair of links connecting said rockers to said front apron, and means movable in horizontal planes for connecting said rockers to said pusher.

4. An excavator comprising a frame including a main bowl, a front apron mounted to'swing in a vertical arc to open and close one end of said bowl, an earth pusher adapted to close the other end of and to move through said main bowl, a

pair of rockers pivoted on said frame to swing in horizontal arcs, a pair of links oneextending along each side of said main bowl and by means of universal joints connecting said rockers to said front apron, and means for connecting said rockers to said pusher.

5:. An excavator comprising a frame including a main bowl, a front apron mounted to swing toward and away from the front end of said bowl, an earth pusher mounted to close the rear end of said bowl and to move into said bowl, a rocker pivoted on said frame behind said pusher, a link extending forwardly from said rocker to said front apron, and connecting means extending forwardly from said rocker to said pusher.

6. An excavator comprising a frame including a main bowl, an upstanding side wall on said main bowl having a, longitudinal aperture therein, a pusher. movable within said main bowl between a rearward position and a forward position, a carriage included with said pusher and in the rearward position thereof adapted to overlie said aperture, means on said pusher extending through said aperture, and means mounted on said extending means for moving said pusher.

'7. In an excavator having a front apron and an earth pusher movably mounted on a frame, linkage connecting said pusher and said front apron including a rocker pivoted intermediate its ends to said franie at a rioint to the rearof wsaid pusher, and means applied to 'saidrocker for actuating said pusher and said front apron.

8; An excavator comprising; a frame including a main bowl; apusher mounted within said bowl for movement between the rear and for- Ward ends of said bowl; 3, front apron movably mounted on said frame for closin'gthe forward for connecting isaid pusher and front apron respectively to the opposed arms 'of said rocker, so

1 that movement of either said pusher, front apron or rocker is imparted to the other two members.

VELISWOR'I'H w. 'AUs'rrN;

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