US3274711A

US3274711A - Earth scraper with retractable bottom wall

Info

Publication number: US3274711A
Application number: US279987A
Authority: US
Inventors: Charles M Johnson; James E Lowder
Original assignee: Johnson Manufacturing Co
Current assignee: Johnson Manufacturing Co
Priority date: 1963-05-13
Filing date: 1963-05-13
Publication date: 1966-09-27
Anticipated expiration: 1983-09-27

Description

Sept. 27, 1966 c. M. JOHNSON ETAL 3,274,711

EARTH SCRAPER WITH RETRACTABLE BOTTOM WALL Filed May 13, 1963 4 Sheets-Sheet 1 INVENTORE: 1/07/4450 ,/4/1$ Elan p56 ATTORNEYS C. M. JOHNSON ETAL Sgpt. 27, 1966 EARTH SCRAPER WITH RETRACTABLE BOTTOM WALL Filed May 13, 1965 4 Sheets-Sheet 2 INVENTOR5 64 446166 1 f JZ/s A/5a/V Jiwaijl awfe ATTORNEYS P 27, 1966 c. M. JOHNSON ETAL 3,

EARTH SCRAPER WITH RETRACTABLE BOTTOM WALL Filed y 13, 1963 4 Sheets-Sheet 4 17g INVENTORS awezfs wja m/ J/wqsi. [Oh/175E ATTORNEYS United States Patent 3,274,711 EARTH SCRAIER WITH RETRACTABLE BQTTOM WALL Charles M. Johnson and James E. Lowder, Lubbock,

Tex., assignors to Johnson Manufacturing Company,

Lubbock, Tex., a corporation of Texas Filed May 13, 1963, Ser. No. 2759987 14 Claims. (Cl. 37129) This invention relates to improvements in earth-moving and scraping machines of the mobile type which include an open-front dirt container having a scraping blade at the front of container and a bottom wall portion which is movable rearwardly to aid in discharging dirt from the container. In particular, it relates to improvements in the construction, mounting and operation of the movable bottom wall portion.

In one known type of scraping machine a separate forward section of the bottom wall of the dirt container is mounted slightly below the rear section of the bottom wall so as to be slidable beneath the rear section. Conventionally, the slidable wall section is suspended from the container by means of rollers which ride on tracks secured to the side walls. In one type of conventional construction, the slidable wall section is power-driven, and the downwardly and forwardly extending scraper blade is secured to the front edge of the section so that there is no obstruction to the discharge of dirt during a dumping operation. As a consequence of this construction the slidable wall section is subjected to strong rearward and downward forces during a dirt scraping operation. These forces are transmitted to the rollers or other support means and to the drive for the wall section unless prevented from doing so.

In another type of conventional construction the scraper blade is fixedly attached to the frame of the machine rather than to the movable bottom wall section. While no substantial rearward forces are transmitted to the movable section in this construction the extremely heavy dirt loads carried by the section produce large downward forces thereon.

It is a primary object of the present invention to provide an earth-scraping machine having a power-driven rearwardly movable bottom wall section in which rearward forces on the wall section during scraping are effectively prevented from being transmitted to the drive for the wall section.

It is a further object of the invention to provide an earth-scraping machine having a rearwardly movable bottom wall section which is mechanically locked against rearward movement during scraping so that rearward forces are not transmitted to the drive for the wall section.

It is a still further object to provide a machine of the above type in which a simply constructed effective latch arrangement carried by the machine is adapted to releasably lock the movable bottom wall section in its forward position.

Another object is to provide an earth-scraping machine having a movable bottom wall section with releasable latching means at the forward end of the scraper for supporting the wall section against downward movement relative to the remainder of the scraper during a scraping operation.

Broadly, these and other objects of the invention are achieved by mechanically supporting the movable bottom wall section against rearward and downward movement during a scraping operation. Preferably, the arrangement which prevents rearward movement includes a latch structure supported from the scraper frame and incorporated in the drive for the movable wall section and adapted to be automatically released upon actuation of the drive in a rearward direction. The arrangement which prevents downward movement of the movable wall section preferably includes a latch structure at the forward end of the machine. The forward latching structure may also include means for resisting rearward movement of the wall section.

The invention will be more fully understood from the following detailed description taken with the drawings in which:

FIGURE 1 is a side elevational view of a scraping machine embodying the principles of the present invention, the machine having a movable bottom wall section carrying a scraper blade at the forward edge thereof;

FIGURE 2 is a side elevational view, partly broken away, of the machine of FIGURE 1 with the parts in a full-dump position;

FIGURE 3 is a fragmentary view, on an enlarged scale, looking in the direction of the arrows 3-3 of FIGURE 1;

FIGURE 4 is a fragmentary side elevational view, on an enlarged scale, of the latching arrangement at the front of the movable bottom wall section;

FIGURE 5 is a fragmentary view looking from the left of FIGURE 4;

FIGURE 6 is a fragmentary view of the latching arrangement at the rear of the movable bottom wall section;

FIGURE 7 is a fragmentary view illustrating a locking pin in combination with the front latching arrangement of FIGURE 4;

FIGURES 8 and 9 are side elevational views of a modification of the front latching arrangement;

FIGURE 10 is a fragmentary elevational view of the forward end of a scraping machine having a fixed scraper blade and a latch for supporting the movable bottom wall against downward movement;

FIGURE 11 is a fragmentary bottom plan view of the machine of FIGURE 10;

FIGURE 12. is a sectional view taken on the line 1212 of FIGURE 11;

FIGURE 13 is a sectional view taken on the line 1313 of FIGURE 11; and

FIGURE 14 is a view similar to FIGURE 13 of a modified latch arrangement.

Referring to FIGURES 1 and 2, there is shown therein an earth-scraping machine which includes an open-front dirt-carrying container 10 defined generally by a pair of laterally-spaced vertical side walls 12, a back Wall 14 and a bottom wall which is formed of a fixed rear section 16 and a longitudinally movable section '18 positioned forwardly of and slightly below the rear section 16. A downwardly and forwardly extending dirt-digging scraper blade 19' is secured to the forward edge of the movable wall setcion 18. The container side walls 12 are reinforced by a suitable framework, some of the members of which are located rearwardly of the container 10 and are illustrated at 20.

Rearwardly of the container 10 the machine is provided with a transverse axle which is supported by the frame members 20. A pair of laterally-spaced groundengaging wheels 22 are suitably journaled on the axle for supporting the rear of the machine.

The machine is connected to a tractor (not shown) or other prime mover by means of a Y-shaped beam structure having a pair of laterally-spaced legs 24 which straddle the forward part of the machine and which are pivoted to the outside of the side walls 12 as by bolts 26. *Forwardly of the container 10 the legs 24 converge to form a gooseneck structure 28 which is connected to the tractor by means of a conventional universal coupling (not shown). The forward ends of the side walls 12 terminate in generally tapered nosepieces 30. A hydraulic cylinder 34, for raising and lowering the front of the container 10, is pivoted at one end to the forward edge of each 3 nosepiece 30 at 36 and to the outer end of the respective leg 24 at 38.

Preferably, the machine is provided with an endless, scraper-type conveyor 40 mounted between the side walls 12 in the forward portion of the container. As shown, the scraper is of the type fully described in Patent No. 2,984,022 issued May 16, 1961, and includes a pair of transversely spaced, rigid frame members 42 having mounted thereon a pair of transversly spaced upper drive sprockets (not shown) and a pair of transversely spaced lower rollers 44. The sprockets and the rollers 44 are journaled for rotation about axes transverse to the container 10 and have looped around them a pair of endless chains 46 which carry transverse scraping flights 48.

As described in the aforesaid Patent No. 2,984,022, the conveyor 40 is mounted in the container 10 by means of a rod 50 which is rigidly secured to the conveyor frame members 42 and extends laterally outwardly. Each end of the rod 50 is pivotally connected to a downwardly and rearwardly extending upper support link 52 which is pivoted to the respective container side wall 12 by a bolt 54 positioned generally below the upper end of the conveyor 40. Also pivoted to the bolt 54 is an elongated lower support arm 56 which extends downwardly and forwardly to a pivotal connection with a second transverse rod 58. By this construction the conveyor 40 is free to rock upwardly about the bolt 54 so as to allow large stones or other debris to pass under the lower end of the conveyor. Downward movement of the conveyor is limited by an inwardly-extending stop member (-not shown) secured to the inner surface of each side wall 12 so as to be engaged by the ends of the rod 58.

Conveniently, the drive system for the conveyor 40 is hydraulically or electrically operated so as to simplify the transmission of power to the scraping machine. As shown, a hydraulic pump 60 is secured to the rear of the tractor and is provided with a suitable control valve 62 and control rod 64, the latter being movable through an appropriate linkage by the tractor operator to control the pump output. Flexible hydraulic conduits 66 lead from the pump to a hydraulic motor 68 which is mounted on the gooseneck structure 28 adjacent the forward ends of the legs 24.

The hydraulic motor 68 has an output shaft 69 which connects with a gear reduction unit 70 through a telescopic shaft 71 and fore and aft universal joints "72. The gear reduction unit 70' is secured to one of the frame members 4-2 of the conveyor 40 by means of a downwardly facing channel member 74 and has an output shaft transverse to the conveyor 40 and drivingly connected to the conveyor sprockets. A flywheel contained with-in a housing 76 is rotatable with the input shaft of the gear reduction unit 70 and serves to reduce pressure surges Within the hydraulic system. A fulil description of a hydraulically operated conveyor carried by an earth-scraping machine appears in the copending application of Johnson and Lowder entitled Earth Scraper with Hydraulically Operated Conveyor, Serial No. 425,43 3, filed January 14, 1965.

The movable bottom wall section 1 8 is suspended from the side walls 12 by means of rollers 78 which are rotatable about transverse axes and which are carried on longitudinally spaced cars extending upwardly from the sides of the wall section 18. The rollers 78 are movable along and supported by a horizontal guide rail 82 secured to the exterior of each container side wall 12. The guide rails 82 are of sufficient length to permit the movable wall section 18, which is suspended by the rollers 78 and cars '80 below the \level of the fixed wall section 16, to move completely under the fixed sect-ion 16 during a dump-ing operation.

As seen in FIGURES I3 and 6 and according to the present invention, the movable bottom wall section 18 is provided with a power-driven, longitudinal drive mechanism and with a latch arrangement which prevents the transmission of rearward force from the wall section 18 to the drive during a scraping operation. As shown, the drive mechanism includes a double-acting hydraulic cylinder 84 located rearwardly of the container back wall 14 and pivoted at its rear end to one of the frame members 20 at 86- for rotational movement about a transverse axis. A movable piston rod 88 extends forwardly from the cylinder and is pivoted by means of a transverse bolt 90 to a linkage arrangement which forms part of the drive mechanism. The drive mechanism together with the latch arrangement serves to lock the movable bottom wall section 18 against rearward movement when the rod 88 is extended and to simultaneously release the wall section 18 and move the same rearwardly upon retraction of the rod 88.

The latch arrangement includes a latch member 92 pivoted at its forward end to the rear edge of the fixed bottom wall section 16 for rotation in a vertical plane. Conveniently, a rearwardly extending ear 93 is provided at the center of the rear edge of the wall section 16 and the latch is pivoted thereto by a transverse bolt 94. The rear end of the latch 92 has a downwardly extending lip 96, the forward surface of which is engageable with the rear end of a rigid dump link 98. The dump link 98 is pivoted at its forward end at 100 to a rearwardly extending ear 102 on the center of the rear edge of the movable bottom wall section 18-.

Near its rear end the dump link 98 is pivoted to the lower end of an upwardly extending dump arm 104 by means of a transverse bolt 106. As seen in FIGURE 3, the dump arm 104 is formed by a pair of laterally-spaced members 104a and 1114b which straddle the dump link 98. The upper end of the dump arm 104 is pivoted at 107 to a transverse frame member 20 rearwardly of the container back wall '14.

Movement of the latch 92 to a disengaged position is effected by means of a latch release arm 108 which forms part of the aforesaid drive mechanism for the bottom wall section '18. As best seen in FIGURES 2 and 6 the release arm 108 is a hook-shaped element pivoted intermediate its ends by a bolt 109 extending transversely between the members 104a and 10% above the pivot bolt 106. The lower end or book portion 110 of the release arm 108 is insertable within the rear end of a longitudinal hole 112 through the latch 92 so that upward movement of the release arm disengages the lip 96 [from the rear end of the dump link 98. A stop member 1 13 secured between the dump arm members 104a and 10 1b is engaged by the upper forward edge of the release arm 108 upon insertion of the hook portion into the hole 112. The upper end of the release arm 108 is pivoted to the extensible rod 88 by means of the transverse bolt 90.

Referring to FIGURES 1, 4 and 5 there is shown, near the front of each side of the movable bottom wall section 218, a laterally extending fixed pin 1 14 which engages with a support flange 116 when the wall section 18 is in the full forward position. The support flanges 116 are vertical plate-like members depending from the nosepieces 30 of the container side walls 12. Each support flange 116 is provided with a rearwardly facing notch 118 which receives one of the pins 114 so as to support the front of the wall section 18 against downward movement during a scraping operation.

The latch pins 114 may be separate structures secured as by welding to the sides of the movable wall section 18 or they may be the opposite ends of a rod which extend across the wall section 18 and which serves also as a transverse reinforcing member. In the embodiment illustrated the pins 114 are separate elements, each one of which is rigidly secured to the lateral surface of a reinforcing plate 120 which extends downwardly from the wall section 18.

FIGURE 7 illustrates a modification of the forward latching arrangement for the movable wall section 18 in which a pair of vertical, movable retaining pins 122 are provided for locking the latch pins 114 in the slots 118. A double-acting air cylinder 124 is secured to the exterior of each container side wall 12 above and slightly rearwardly of each slot 118. A slidable piston 126 in each cylinder 124 is connected to one of the retaining pins 122 for moving the same upwardly or downwardly as air pressure is delivered to the lower or upper surface of the piston 126 through conduits 128. A suitable source of air pressure is carried either by the scraping machine or the prime mover and delivery of air to the cylinder 1 24 may be controlled manually by the operator. If desired, the cylinder 124 may be actuated automatically to move the retaining pins 122 downwardly to their locking positions when the movable wall section 18 reaches its full forward position. For example, a limit switch associated with the pressure control for the cylinder 124 may be mounted on one of the container side walls 12 in a position in which .it will be actuated by the forward end of the wall section 18 or by one of the pins 114 upon entry of the pins 114 into the slots 118.

In the construction illustrated in FIGURE 7 the latch pins 114 extend beyond the flanges 116 further than is shown in FIGURE 5 so that the retaining pins 122 may be located between the flanges 1'16 and the outer end of the pins 114. In addition, each flange 116 is provided with a pair of vertically spaced guides 130 through which the retaining pins 122 are slidable. The guides 130 are located above and below their respective slot 118 and therefore serve not only to accurately locate the retaining pins 122 immediately rearwardly of the latch pins 114, but also to prevent transmission of stresses to the air cylinders 12 4 from the Wall section 18 during a scrap ing operation.

The rear wall 1 4 of the container '10 is longitudinally movable and is power-driven in either a forward or rearward direction by a pair of horizontally spaced doubleacting hydraulic rams 132. The rams 132 are disposed rearwardly of the wall 14 with their rear ends pivoted to one of the frame members 20 at 134 and their forward ends pivoted at 1 36 to horizontally spaced ears 138 on the rear surface of the wall 14. The top and bottom of the rear wall 14 are supported and guided by means of rollers 1'40 and 142, respectively. One upper roller 140 is journaled on each lateral edge of the rear wall 14 for rolling engagement with a track 144 secured to the inside of the corresponding container side wall 12. The lower rollers 142 are journaled on ears 146 extending from the back of the rear wall 14 and engage the upper surface of the .fixed bottom wall section 16.

FIGURES 8 and 9, in which primed reference numerals designate parts which are the same as or analogous to parts already described, illustrate a modified arrangement for retaining the laterally extending latching pins in their respective slots during a scraping operation. As before, the movable bottom wall section 18' is mounted by means of rollers 78' which engage a track 82' on the exterior of each container side wall 12'. A latch pin 114' extends laterally from each side of the wall section 18 so as to be insertable into a complementary rearwardly facing slot 118' formed in a flange 116. The forward end of the container is supported by laterally spaced arms 24' pivoted to the side walls 12 at 26 and by a pair of double-acting hydraulic cylinders 34 pivoted to the nosep-ieces 30.

A pin-retaining lever 152 is pivoted intermediate its ends to the exterior of each nosepiece 30' above and forwardly of the slots 118' at 154. A spiral tension spring 156 connected between the nosepiece 30' and the lever 152 above the pivot 154 urges the lever 152 counterclockwise as viewed in the drawing. In the position shown in FIGURE 8 a hook-like portion 158 on the lower end of each lever 152 engages the rear surface of the corresponding latch pin 114' and thereby locks it in its slot 118'. When the forward part of the container 10' is raised by the cylinders 34', the upward-1y extending ends of the levers 152 engage a boss 162 on the lower surface of the arms 24. Continued upward movement of the container 10' causes the levers 152 to be rotated clockwise as viewed in the drawing so that the hook-like portions at the lower end of the levers 152 disengage from the latch pins 114. The movable Wall section 18' may then be retracted by means of the previously described drive operating through the dump link 98.

While the above-described latches at the forward end of a scraping machine have been described in combination with a movable bottom wall section which carries a scraper blade at its forward edge, it will be understood that they may be employed in a machine in which the movable wall section does not carry the scraping blade. FIGURES 10-13 illustrate such a scraping machine 10" in which a latch arrangement similar to that illustrated in FIGURES 4, 5 and 7 is employed.

Referring to FIGURES 10-13 the scraping machine 10" illustrated therein is the same as those already described except that it has a scraper blade 166 fixedly attached to and supported by a transverse moldboard 168. The moldboard 168 includes a heavy plate 170 secured at its ends to a pair of nosepieces 172 which extend forwardly from side walls 174 of the machine 10". The scraper blade is secured .to the forward portion of the plate which extends downwardly and forwardly. A plurality of horizontally spaced reinforcing member 176 are secured to the lower surface of the plate 170 and are provided with rearwardly facing open slots 178 in their rear edges.

A movable bottom wall section 180, mounted for longitudinal sliding movement as described before terminates at its forward edge in a rigid bar 182 which extends laterally to points outside the nosepieoes 172. In the full forward position of the wall section 180, as seen in the drawing, the bar 182 resides in the slots 178 so as to be supported thereby against vertical movement. The rod is also supported near each end by engagement with a rearwardly facing slot 184 in each nosepiece 172. A pair of laterally spaced radial guide flanges 186 are secured to the rod 182 near each end thereof to aid in guiding the rod 182 into the nosepiece slots 184.

As in the embodiment of FIGURE 7, the fixed-blade machine 10" of FIGURES 10-13 is provided with a hydraulically operated locking pin 122 and cylinder 124 for locking the movable wall section in its full forward position. As seen in FIGURES 11 and 12, one of the cylinders 124 is mounted on the outside of each nosepiece 172 in a position such that the respective pin 122 can be extended to a position immediately rearward of the bar 182.

FIGURE 14 illustrates another manner of supporting the forward edge of a movable bottom wall section in a fixed-blade machine. In this construction a fixed moldboard plate 170 having a scraper blade 166' secured to the forward portion thereof is provided as before. A plurality of reinforcing members are secured to the lower surface of the plate 170' and are provided with rearwardly facing V-shaped slots 188. The forward edge of the movable wall section 180 is pointed as at 190 so as to fit within the slots 188. If desired, the lateral edges of the wall section 180' may be provided with laterally extending latch pins for engagement with nosepiece slots as shown in the FIGURE 7 construction. Hydraulic locking pins for restraining rearward movement of the wall section 180 may also be provided if desired.

In operation of the scraping machine of FIGURES l-7, loading of the container 10 is effected by extending the hydraulic cylinder 34 so as to lower the scraper blade 19 into engagement with the ground and by towing the container 10 forwardly by means of a prime mover. Loosened dirt passing over the blade 19 is engaged by the conveyor flights 48 which are moved clockwise as viewed in the drawing and is urged rearwardly into the container.

Of course, before a scraping operation is begun the container rear wall 14 will be fully retracted and the movable bottom wall section 18 will be locked in its full forward position. These positions are shown in FIGURE 1 and are effected by retracting the hydraulic cylinders 132 and extending the hydraulic cylinder 84. The movable wa-ll section 18 is prevented from moving rearwardly upon engagement of the scraper blade 19 with the ground by the pivoted latch member 92 which is permanently connected to the fixed bottom wall section 16 and which engages the rear end of the dump link 98. As seen in FIGURE 1, the latch release arm 108 has no effect on the latch 92 at this time because the release arm 108 is held against the stop member 113 by the rod 88. The forward end of the movable wall section 18 is supported against downward movement by the engagement of the lateral latch pins 114 with the slots 118 in the flanges 116. Further support against rearward movement of wall section 18 may be obtained with the use of the retaining pins 122 shown in FIGURE 7.

When the container has been loaded, the cylinders 34 are retracted to raise the scraper blade 19 above the ground,-as seen in FIGURE 2, for transporting and dumping, and when it is desired to discharge the dirt load, the movable bottom wall section 18 is retracted and the movable rear wall 14 is pushed forwardly.

When the cylinder 84 is actuated to begin retraction of its rod 88 the latch release arm 108 is rotated counterclockwise about point 108 with the result that the hook portion 110 of the release arm 108 lifts the latch 92 out of engagement with the rear end of the dump link 98. The dotted line positions of the rod 88, release arm 108 and latch 92 in FIGURE 6 illustrate this operation. Continued retraction of the rod 88 rotates the dump arm 104 clockwise about the point 107 so that the dump link 98 and the movable bottom wall section 18 are moved rearwardly to the positions shown in FIGURE 2.

The operation of the machine illustrated in FIGURES 8 and 9 is the same as that described above except that the latch pins 114' are automatically locked in their slots 118 by the levers 152 upon lowering of the container 10' with the cylinders 34'. As already described, the levers 152 are biased toward a pin-locking position by the tension springs 156 and are moved away from the pins 114' upon engagement of the upper ends of the levers 152 with the arms 24.

The operation of the apparatus of FIGURES 10-14 is analogous to that of the other embodiments and needs no special description.

It will thus be seen that the objects of this invention have been fully and effectively accomplished. It will be realized, however, that the foregoing specific embodiments have been described only for the purpose of illustrating the principles of the present invention and are subject to change without departing from such principles. Therefore, this invention includes all modifications encompassed within the scope of the following claims.

What is claimed is:

1. In an earth-moving apparatus which includes a mobile, open-front dirt-carrying container and a forwardly and rearwardly movable bottom wall section which carries a dirt-digging scrapper blade at the forward end thereof, the improvement which comprises: a movable latch member carried 'by said container for movement between a first position in which it restrains said movable wall section against rearward movement and a second position in which it permits rearward movement of said wall section; a power-driven drive mechanism carried by said container and connected to said wall section for moving the same forwardly and rearwardly, said mechanism including a release arm engageable with said latch member when in said first posit-ion for moving the same to said second position upon actuation of said mechanism in a direct-i011 to move said wall section rearwardly.

2. Apparatus as in claim 1 wherein said drive mechanism includes: a dump link pivoted at one end to the rear end of said movable wall section for movement in a vertical plane; a dump arm pivoted to the other end of said dump link and to said container for movement in a vertical plane, said release arm being pivotally connected intermediate its ends to said dump arm intermediate the ends of said dump arm; and reversible-thrust power means connected to one end of said release arm, the other end of said release arm being engagable with said latch member whereby movement of said power means in a rearward direction engages said other end of said release arm with said latch member to move the same to its release position and thereafter moves said wall section rearwardly.

'3. In an earth-moving apparatus which includes a mobile, open-front dirt-carrying container having a reinforcing frame and a forwardly and rearwardly movable bot-tom wall section which carries a dirt-digging scraper blade at the forward end thereof, the improvement which comprises: a first link pivoted at one end to the rear end of said wall section for movement in a vertical plane and extending rearwardly; a second link pivoted at one end to the rear end of said first link and at its other end to the container frame at a location rearwardly of the back of said container and above the level of said wall section; a latch member pivoted at one end for rotation about a fixed axis which is transverse to said container, the other end of the latch member being movable between a first position in which it engages the rear end of said first link to prevent rearward movement thereof and a second position in which it is out of the rearward path of said first link; a release link pivoted intermediate its ends to said second link intermediate the ends of said second link, one end of said release link being engageable with said latch member to move the same to said second position; and reversible-thrust power means connected to the other end of said release link.

4. Apparatus as in claim 1 further comprising auxiliary support means for restraining downward movement of the front of said wall section, said auxiliary support means including a rigid lat-ch element extending in a generally horizontal plane from the forward part of said wall sect-ion and further including means defining a sup-v port for restraining downward movement of said latch element, said means being secured to said last-named container in a position to be engaged by the lower sur-, face of said latch element when said movable wall section is in its full forward position and to be out of contact with said latch element when said wall section is moved rearwardly.

5. In an earth-moving apparatus which includes a mobile, open-front dirt-carrying container, a movable bottom wall section at the front of said container, means mounting said bottom wall section from said container for relative movement forwardly and readwardly, and a dirt-digging scraper blade carried by and disposed in advance of said movable bottom wall section the improvement comprising: auxiliary support means for restraining downward movement of the front of said wall section when said section is in its forwardmost position, said auxiliary support means including a first member carried by the 'forward portion of said wall section and a sec-0nd member carried by said container at the forward end thereof in a position to be out of contact with said first member when said bottom wall -is in a rearward position and to be engageable with at least the lower surface of said first member when said bottom wall section is in its forwardmost position, to \prevent downward movement of said bottom wall section, said first and second members being disposed at the side of said apparatus out of the line of travel of dirt passing over said scraper blade.

6. In an earth-moving apparatus which includes a mobile, open-front dirt-carrying container and a forwardly and rearwardly movable bottom wall section, the improvement which comprises: a rigid latch element extending in a generally horizontal plane from each side of the forward part of said movable wall sec-tion; means defining a support for restraining downward movement of each latch element, each of said supports being secured to said container in a position to be engaged by the lower surface of its respective latch element when said movable wall section is in its full forward position and to be out of contact .with its respective latch element when said wall section is moved rearwardly, each of said supports defining a forwardly extending slot for receiving its respective latch element.

7. Apparatus as in claim 6 further including a movable lock element for each latch element and movable between a first position in the rearward path of its respective latch element and a second position out of the rearward path of its respective latch element.

8. Apparatus as in claim 7 wherein said lock elements are linearly movable pins.

9. Apparatus as in claim 7 wherein said lock elements are members pivoted for rotation in a vertical plane.

10. In an earth-moving apparatus which includes mobile, open-front dirt-carrying container means having a forwardly and rearwardly movable bottom wall section which carries a dirt-digging scraper blade at the forward end thereof and double-acting hydraulic cylinder means pivotally connected at one end to said container means for moving said bottom wall section, the improvement which comprises: latching means separate from said hydraulic cylinder means for selectively restraining and permitting rearward movement of said wall section from a forward position, said latching means including means associated with said bottom wall section defining a latching surface and further including a movable latch member carried by said container means for movement between a first position in which it engages and restrains movement of said latching surface and a second posit-ion in which it is out of the path of said latching surface; and latch release means carried by said hydraulic cylinder means for engaging said latch member when the latter is in said first position and for moving the same to said second position upon actuation of said hydraulic cylinder means in a direction to move said bottom wall section rearwardly.

1 1. In an earth moving apparatus which includes a mobile, open-front, dirt-carrying container having a reinforcing frame, side walls, a movable bottom wall section at the front of said container, means mounting said bottom wall section for forward and rearward movement relative to said side walls and a dirt-digging scraper blade carried by and disposed in advance of said movable bottom wall section, the improvement comprising: auxiliary support means for restraining vertical movement of the forward end of said movable bottom wall section when said section is in its forwardmost position, said auxiliary support means including a fixed rigid support member secured to said container at the forward end thereof, said support member having a generally upwardly facing supporting surface and a generally downwardly facing restraining surface, said auxiliary support means further including a rigid latch element carried at the forward end portion of said movable bottom wall section, said latch element having a generally downward- 1y facing latching surface which engages said generally upwardly facing supporting surface when said bottom wall section is in its forwardmost position and a generally upwardly facing latching surface which engages said restraining surface when said bottom wall section is in its forwardmost position.

12. Apparatus as in claim 11 wherein said support member is disposed along the forward portion of a side wall out of the line of travel of dirt passing over said scraping blade, wherein said latch element is disposed at one side of said bottom wall section out of the line of travel of dirt passing over said scraping blade and wherein a second support member and latch element is similarly disposed on the other side of said container and bottom wall section, respectively.

13. Apparatus as in claim 112 wherein said support member on each side of said container is defined by a forward extension of the respective side wall, each extension lying generally in the plane of its respective side wall, and wherein each of said latch elements is defined by a lateral projection on said movable bottom wall section.

14. in an earth-moving apparatus which includes a mobile, open-front, dirt-carrying container and a forwardly and rearwardly movable bottom wall section which carries a dirt-digging scraper blade at its forward end the improvement which comprises: a rigid latch element extending in a generally horizontal plane from the forward part of said movable wall section; and means defining a support for restraining downward movement of said latch element, said means being secured to said container in a position to be engaged by the lower surface of said latch element when said movable wall section is in its full forward position and to be out of contact with said latch element when said wall section is moved rearwardly and a movable lock-ing element supported by said container and movable between a first position in the rearward path of said latch element so as to prevent disengagement of said latch element from its support means and a second position out of the rearward path of said latch element whereby said movable locking element tends to restrain rearward movement of said latch element during a dirt-digging operation.

References Cited by the Examiner UNITED STATES PATENTS 2,112,105 3/1938 =Le Tourneau 37- 126 2,229,103 1/1'941 'Le Tourneau 37--126 2,494,472 1/ 1950 De Saussure 298----35 2,738,739 3/ 1956 Dorey \282 2,836,461 5/ 1958 Shadwick et al. 298-35 2,989,931 6/ 1961 Joy 105-282 2,994,976 8/1961 Hancock 37-8 OTHER REFERENCES Chase, R. A.: Locking Mechanisms for Hydraulic Actuators. In Product Engineering, vol. 27, No. 6, pp. 164-166, June 1956.

ABRAHAM G. STONE, Primary Examiner. BENJAMIN HERSH, Examiner.

G. T. MOLLER, R. L. HOLLISTER,

Assistant Examiners.

Claims

5. IN AN EARTH-MOVING APPARATUS WHICH INCLUDES A MOBILE, OPEN-FRONT DIRT-CARRYING CONTAINER, A MOVABLE BOTTOM WALL SECTION AT THE FRONT OF SAID CONTAINER, A MOVABLE MOUNTING SAID BOTTOM WALL SECTION FROM SAID CONTAINER FOR RELATIVE MOVEMENT FORWARDLY AND READWARDLY, AND A DIRT-DIGGING SCRAPER BLADE CARRIED BY AND DISPOSED IN ADVANCE OF SAID MOVABLE BOTTOM WALL SECTION THE IMPROVEMENT COMPRISING: AUXILIARY SUPPORT MEANS FOR RESTRAINING DOWNWRD MOVEMENT OF THE FRONT OF SAID WALL SECTION WHEN SAID SECTION IS IN ITS FORWARDMOST POSITION, SAID AUXILIARY SUPPORT MEANS INCLUDING A FIRST MEMBER CARRIED BY THE FORWARD PORTION OF SAID WALL SECTION AND A SECOND MEMBER CARRIED BY SAID CONTAINER AT THE FORWARD END THEREOF IN A POSITION TO BE OUT OF CONTACT WITH SAID FIRST MEMBER WHEN SAID BOTTOM WALL IS IN A REARWARD POSITION AND TO BE ENGAGEABLE WITH AT LEAST THE LOWER SURFACE OF SAID FIRST MEMBER WHEN SAID BOTTOM WALL SECTION IS IN ITS FORWARDMOST POSITION, TO PREVENT DOWNWARD MOVEMENT OF SAID BOTTOM WALL SECTION, SAID FIRST AND SECOND MEMBERS BEING DISPOSED AT THE SIDE OF SAID APPARATUS OUT OF THE LINE OF TRAVEL OF DIRT PASSING OVER SAID SCRAPER BLADE.