US 3388487 A
Description (OCR text may contain errors)
June 18, 1968 R. B. PECK TRENCHING APPARATUS 3 Sheets-Sheet 2 Filed July 16, 1965 Iii-Z- INVENTOR: RAYM 01m .5. PE CK A ys.
June 18, 1968 Q R. B. PECK 3,388,487
TRENCHING APPARATUS Filed July 16, 1965 S Sheets-Sheet 3 INVENTOR. RAYMDND B. PEEK.
United States Patent 3,388,487 TRENCHING APPARATUS Raymond B. Peck, Rte. 1, Holgate, Ohio 43527 Filed July 16, 1965, Ser. No. 472,610 Claims. (CI. 37-90) ABSTRACT OF THE DISCLOSURE Trenching apparatus for use with a self-propelled vehicle. The trenching apparatus includes a support adjacent the rear of the vehicle. The support mounts a digger assembly for movement along a generally vertical guide path. The digger assembly includes a chain support member and a closed loop digging chain. An earth backboard member is mounted interiorly of the chain loop and a shielding member is spaced forwardly of the backboard member. A portion of the earth backboard member and the shielding member define a passageway for excavated earth. Earth removal mechanism is mounted adjacent the vehicle and forwardly of the chain loop. The apparatus also includes chain driving means and means for adjustably positioning the digger assembly along the guide path.
This invention relates to excavating equipment and, more particularly, to improved trenching apparatus.
The present invention is an improved trencher which has the capability of digging a trench to an established grade. After the trench has been excavated, pipe may be laid in the trench without additional hand digging.
In some parts of this country, for example, in the region extending between Cleveland, Ohio, and Fort Wayne, Ind., the terrain is generally flat. It is not unusual for sanitary sewers or storm sewers to be laid at a 0.3 percent grade or less. Prior art automated trenching apparatus is incapable of accuately digging a trench having such a fiat grade. Furthermore, prior art trenchers are generally ineffective in excavating trenches to depths greater than four feet and are also ineffective in digging through rocky soil or hardpan. For this reason, when trenches are dug at depths of seven feet or greater, it is common to use either a dragline or a backhoe rather than a prior art trencher.
One type of prior art trencher is a trencher in which buckets are mounted at the rear of a vehicle and move in a circular, generally vertical, path. As the buckets come upwardly, they excavate the trench. The buckets then continue upwardly and the excavated soil is discharged on a conveyor as it begins its downward movement. An example of this type of prior art trencher is disclosed in US. Patent 2,692,446.
Another type of prior art trencher is one having a cantilevered boom which extends from the rear end of a vehicle. An endless digger chain excavates the trench. However, because the digger chain is open the excavated soil is continually reworked. It is very difiicult to hold a grade with this type of trencher. This is particularly so when excavating, for example, hard clay. When the rear end of the boom is lowered to take a deeper cut an upward force is created on the rear wheels of the vehicle. In severe conditions, the rear driving wheels have been lifted from the ground and the movement of the digging chain has moved the trencher backwards in the trench.
It is the primary object of the present invention to provide improved trenching apparatus having means for digging a trench to a predetermined grade.
It is another object of the instant invention to provide trenching apparatus having an improved digger assembly whereby soil which has been excavated is prevented from falling backwardly into the trench.
It is a still further object of the present invention to provide trenching apparatus which is extremely maneuverable and which has the capability of digging trenches of relatively deep depth.
It is still another object of the present invention to provide trenching apparatus having a support frame which is movable between a generally vertical operating position and a generally horizontal traveling position.
Still further objects of the present invention. will become apparent from the following specification and drawings in which:
FIG. 1 is a side view in elevation, partially in cross section, of trenching apparatus, according to the present invention, and showing a portion of a trench which is being excavated;
FIG. 2 is a rear view of the trenching apparatus shown in FIG. 1, with some of the parts omitted for clarity;
FIG. 3 is a sectional view taken along the line 33 of F IG. 2 and shown on an enlarged scale;
FIG. 4 is a view similar to FIG. 1, showing another embodiment of the present invention in which a section of the trenching apparatus support frame is movable between a generally vertical operating position and a generally horizontal traveling position; and
FIG. 5 is a fragmentary side view showing the jointed connection between the upper and lower sections of the support frame, with portions omitted for clarity and shown on an enlarged scale.
Briefly, the present invention relates to a trenching apparatus including a self-propelled vehicle. A longitudinally extending support frame is mounted adjacent the rear end of the vehicle. The support frame defines a longitudinally extending guide path and a digger assembly is mounted for movement along the guide path. The digger assembly comprises a chain support member, a closed loop digging chain mounted for movement on the chain support member, and an earth backboard member mounted interiorly of the chain loop. Earth conveyor means are mounted adjacent the vehicle exteriorly of the chain loop. The trenching apparatus also includes means for driving the chain and means for adjustably positioning the digger assembly along the guide path defined by the support frame.
Referring to FIG. 1 of the drawings, an improved trenching apparatus according to the present invention is indicated at 10. The trenching apparatus 10 includes a self-propelled vehicle 11 having a pair of front wheels 12 and a pair of rear wheels 13. The front wheels 12 are mounted on a front axle 14 and the rear wheels 13 are mounted on a rear axle 15. A chassis 16 is supported by the respective axles 14 and 15. An engine (not shown) is mounted on the chassis 16 and a transmission means, generally indicated by the reference number 17 is mounted on the chassis 16. Preferably, the transmission means 17 is capable of enabling the self-propelled vehicle 11 to operate at high speeds during transportation of the trenching apparatus 10 and at low speeds when the trenching apparatus 10 is in the operating position, as shown in FIG. 1.
v The transmission means 17 may consist of two separate 3-speed transmissions, the first acting as a high speed transmission and the second acting as a low speed transmission, or in the alternative, a specially designed unitary transmission having both high speed and low speed capabilities may be utilized.
A longitudinally extending, and generally vertical, support frame 20 is mounted on the chassis 16 adjacent the rear end of the self-propelled vehicle 11. In the present embodiment, the support frame 20 includes four vertically extending angles 21 which are joined together by top webs 22 and bottom webs 23. It should be understood that the support frame 20 may be constructed of several configurations and materials, for example tubular members may be used rather than the angles 21.
The interior surfaces of the angles 21 define a longitudinally extending guide path, generally indicated by the reference number 24. A digger assembly 25 is mounted interiorly of the angles 21 for movement along the guide path 24. The digger assembly 25 includes a longitudinally extending chain support member 26 which comprises two opposed vertical plates 27 and 28 and a head member 29. The head member 29 is generally box shaped and has an outer surface which is complementary with the guide path 24 defined by the angles 21. The plates 27 and 28 depend from the head member 29 and are spaced inwardly of the interior surfaces of the angles 21 (see FIG. 2).
An upper chain sprocket 30 is carried by a sprocket shaft 31 which is mounted for rotation on the head member 29. A lower chain sprocket 32 is mounted on a sprocket shaft 33 which extends between the opposed plates 27 and 28 of the digger assembly 25. In the present embodiment, a bracket 34 extends rearwardly from the opposed plates 27 and 28 and mounts an idler sprocket 35.
A closed loop digging chain 36 is mounted for movement on the chain support member 26. The digging chain 36 is supported by the upper chain sprocket 30, the lower chain sprocket 32, and the idler sprocket 35. In the instant embodiment, a single closed loop digging chain 36 is shown. However, a plurality of digging chains may be used. The number of digging chains used depends upon the trench width. If a trench having a greater width is desired two or more digging chains may be utilized.
The digging chain 36 includes a plurality of open cutting teeth 37. The cutting teeth 37 are mounted at spaced intervals along the chain 36. In the present embodiment, the cutting teeth are shown as U-shaped members. However, they may be of other configurations, for example, L-shaped members.
An important feature of the present invention is an earth backboard member 39 which, in the present embodiment, consists of a longitudinally extending plate mounted on the opposed plates 27 and 28 of the chain support member 26. The backboard member 39 has a width slightly less than the width of the cutting teeth 37 (see FIG. 2) and extends from a position immediately above the lower chain sprocket 32 upwardly to a location immediately beneath the upper chain sprocket 30.
Referring to FIG. 1, the trenching apparatus 10 is shown digging a trench 40. As the earth is excavated by the cutting teeth 37, the excavated soil or earth is moved upwardly and the backboard member 39 prevents the excavated soil from falling downwardly into the excavated portion of the trench 40 whereby the returned soil must be reworked either by another machine operation or by hand. While the chain support member 26 is shown in the present embodiment as a generally vertical member, This type of digger assembly is equally suitable to a cantilevered boom type structure which extends at an angle from the rear of a vehicle.
Referring to FIG. 1, a bracket 41 extends outwardly from the upper end of one of the angles 21, of the support frame 20, and mounts an idler pulley 42. A continuous drive cable 43 extends around the idler pulley 42 and thence downwardly around an idler pulley 44 which is mounted on a stub shaft 45 which extends outwardly from the head member 29 of the chain support member 26. The drive cable 43 then extends upwardly around a drive pulley sprocket 46 which i mounted on the sprocket shaft 31. As the drive pulley sprocket 46 rotates, the sprocket shaft 31 and the upper chain sprocket 30 also rotate, thus driving the closed loop digging chain 36. The path of the drive cable 43 continues downwardly around an idler pulley 47 which is mounted on a stub shaft 48 which extends outwardly from one of the bottom webs 23. The drive cable 43 then extends around a driven sprocket 49 which is mounted on a driven shaft 50. The driven shaft 50 is operatively connected to the vehicle drive shaft. The drive cable 43 also extends around an idler pulley 51 which is supported by a bracket 52 which extends upwardly from the chassis 16. The path of the drive cable 43 then continues upwardly passing over the idler pulley 42, thus completing the circuit.
The chain support member 26 moves vertically along the guide path 24 defined by the support frame 20 and the drive cable path described above is designed to keep constant tension on the drive cable 43. As shown in FIG. 1, the idler pulley 44 and the drive pulley sprocket 46 are mounted on the head member 29 of the support member 26 and move with the support member 26. The remainder of the pulleys or sprockets remain in a fixed location.
Referring to FIG. 2, means for adjustably positioning the digger assembly 25 along the guide path 24 are generally indicated by the reference number 55. The positioning means 55 includes a winch 56 mounted on the support frame 20. Automated winches, for examples, electric or hydraulic winches are within the contemplation of the present invention. A winch cable 57 extends upwardly and passes over a pair of idler pulleys 58 which are mounted on the top webs 22 of the support frame 20. An end 59 of the winch cable 57 is connected to the head member 29 of the chain support member 26. When it is desired to dig a trench to a deeper elevation, the cable 47 is extended and the chain support member 26 moves downwardly along the guide path 24 defined by the support frame 20. Conversely, when a shallower depth is desired, the winch 56 is operated and the cable 57 is retracted thus raising the chain support member 26. Because the digging action of the chain 36 creates a downward reaction on the support member 26, the cable 57 remains in tension or in a taut position throughout the digging operation.
Means for correlating the vertical position of the digger assembly 25 with an established grade, for example, a surveyors sewer grade, is indicated by the reference number 60 (see FIG. 2). The corrrelating means 60 includes a bracket 61 which is mounted on and extends outwardly from the head member 29. The bracket 61 moves upwardly and downwardly with the chain support member 26. The bracket 61 mounts a sightbar 62 which has a longitudinally extending horizontal run (not shown) along its bottom edge. The horizontal run of the sightbar is positioned a predetermined distance above the bottom of the cutting chain 36 as indicated by the reference number 37a in FIG. 2. As is well known, when sanitary sewers or the like are installed on a predetermined grade, a surveyor sets a grade line which runs parallel to the center line of the trench, or in the alternative, a series of batter boards which run transversely of the trench at predetermined spaced intervals. When utilizing the trenching apparatus 10, an operator establishes a datum plane which is a given distance above the established grade line of the sewer. The distance between the data plane and the grade line of the sewer is equal to the predetermined distance between the bottom of the digging chain 36 and the horizontal position of the sightbar 62. When the operator is digging a trench, if he is digging a trench to a relatively steep grade, he merely sights along the horizontally extending portion of the sightbar 62 and visually checks to see if the sightbar 62 is at the same elevation as the preset datum plane. If the sightbar 62 is higher or lower than the datum plane, he makes an adjustment with the winch 56 and either raises or lowers the winch cable 57 thereby raising or lowering the bottom of the digging chain 36. However, if he is working to an xtremely fiat grade, it is necessary to take periodical direct measurements between the sightbar 62 and the datum plane, rather than relying solely upon visual checks.
Referring to FIGS. 1 and 2, a horizontal earth or soil conveyor 65 is mounted on the rear end of the vehicle 11. The conveyor 65 includes a conveyor chute 66 having a soil discharge opening 67. A screw conveyor 68 is mounted for rotation within the chute 66 and is driven by a belt 69 which is operatively connected to the driven shaft 50.
The location of the soil conveyor 65 adjacent the vehicle 11 is an improvement over prior art bucket type trenches. After the prior art buckets were filled, they moved upwardly, over the top of the path and the soil was discharged onto conveyors located on the far side of the vehicle. In the present invention, because the soil within the trench 39 is removed with an open chain cutter, rather than buckets, the soil is moved upwardly and is discharged upon the soil conveyor 65 after a relatively short travel. By utilizing the open type digging chain 36, and the earth backboard member 40, it is possible to achieve the maneuverability afforded by a vertical digging operation and at the same time eliminate the undesirable bucket type conveyors.
Referring to FIGS. 1-3, an earth shield 70 is preferably mounted in the support frame 20 adjacent the vehicle 11. The earth shield 70 is generally rectangularly shaped having a U-shaped vertical cross section. The shield 70 includes opposed longitudinally exending sides 71 and a web 72 extending between the opposed sides. The web 72 defines a discharge opening 73 which communicates with the soil conveyor 65. The earth shield 70 terminates at a location below the chassis 16 and the upper end terminates below the idler pulley 42. The lower end of the earth shield 70 extends downwardly and terminates above the elevation of the ground. The earth shield 70 and the backboard member 39 define a passageway for the digging chain 36 and serves a dual purpose in that it not only prevents unwanted discharge of the soil as it is carried upwardly by the digging chain 36, but it also protects the operator from being injured by the digging chain 36. Referring to FIGS. 1-3, the excavated earth is moved upwardly by the digging chain 36. Below the ground elevation a portion of the backboard member 39 and the walls of the trench form a passageway for the excavated earth. Above the ground elevation a portion of the backboard member 39 and the earth shield 70 form the passageway for the excavated earth. During operation, as the trenching apparatus moves forward, a mound of earth forms below the shield 10 and serves as a wall portion of the excavated earth passageway. The excavated earth is carried upwardly through the passageway and is discharged through the opening 73 onto the conveyor 65.
The trenching apparatus 10 has the advantages of being able to turn on an extrernly short radius and also, it is capable of digging through hardpan or hard clay. When such soil conditions are encountered, rather than the rear wheels 13 losing traction, as is the case with the prior art cantilivered boom type trencher, the bite of the cutting teeth 37 into the clay results in an additional downward force upon the rear wheels 13. Therefore, the traction is increased, rather than decreased.
A second embodiment of the present invention is shown in FIGS. 4 and 5. In this embodiment, the support frame 20 has an upper section 75 and a lower section 76. Referring to FIG. 5, the upper section 75 is hinged to the lower section 76 by hinges 77, which are mounted on the angles 21 which are located adjacent the vehicle 11. On each of the angles 21 a connecting flange member 78 is mounted at the meeting line between the upper section 75 and the lower section 76. The adjoining flange members 78 on each of the angles 21 have indexing holes 79 extending therethrough and when the support frame 29 is in a generally vertical operating position, as shown by the solid lines in FIG. 5, retaining bolts 80 extend through the adjoining holes 79 and secure the support frame 20 in the upright position.
Referring to FIG. 4, a post 81 is pivotally mounted by a bracket 82 to the front end of the vehicle 11. When it is necessary to move the vehicle 11 for a considerable distance, the post 81 is moved to the vertical position shown by the solid lines in FIG. 4. The retaining bolts 80 are then removed from the flange members 78 and the upper section of the support frame 20 is pivoted downwardly until it reaches a generally horizontal traveling position, as shown by the solid lines in FIG. 4.
While the present invention has been disclosed with a specific arrangement and disposition of the parts, it should be expressly understood that numerous modifications and changes may be made without departing from the scope of the appended claims.
What I claim is:
1. In a trenching apparatus including a selfipropelled vehicle, the improvement comprising, support means mounted adjacent the rear end of such vehicle, said support means mounting a digger assembly for movement along a generally vertical guide path, said digger assembly including a chain support member and a closed loop digging chain mounted for movement on said chain support member, a generally vertical transversely extending earth backboard member mounted interiorly of such chain loop and adapted to terminate below the ground, a generally vertical shielding member spaced forwardly from said earth backboard member, said shielding member having a lower end terminating above the ground, wherein a portion of said earth backboard member and said shielding member define a passageway for excavated earth and wherein such chain loop travels through such passageway, earth removal means mounted adjacent such vehicle exteriorly and forwardly of such chain loop, means for driving said chain, and means for adjustably positioning said digger assembly along such guide path.
2. Trenching apparatus, according to claim 1, in which said backboard member is an integral part of said chain support member. 1
3. A trenching machine-according to claim 1, having a plurality of open bottomed cutting teeth positioned on said closed loop digging chain.
4. A trenching machine according to claim 3 wherein said earth removal means is a conveyor.
5. Apparatus according to claim 4 including means for correlating the vertical position of said digger assembly with respect to an established grade, said correlating means comprising an outwardly extending sightbar mounted on said movable chain support member, said sightbar being mounted on said support member a predetermined distance above the bottom of said digging chain.
6. A trenching machine according to claim 4 wherein said means for adjustably positioning said digger assembly comprises a cable operatively connected to said chain support member and means for moving said cable.
7. A trenching machine according to claim 4 wherein said digger assembly includes a first chain sprocket mounted at one end of said chain support member and a second chain sprocket mounted at the other end of said chain support member, said closed loop digging chain being mounted for movement on said first and second chain sprockets.
8. A trenching machine according to claim 4 wherein a discharge opening is defined by said shielding member adjacent said conveyor in communication with the passageway defined by said earth backboard member and said shielding member, whereby excavated earth is discharged through such discharge opening onto said conveyor.
9. A trenching machine according to claim 4 wherein said support means comprises a vertically extending support frame.
10. Apparatus according to claim 9 wherein said sup port frame has a movable upper section and a stationary lower section, said upper section being pivotally mounted to said lower section and movable between a generally vertical operating position and a generally horizontal traveling position.
(References on following page) 7 8 References Cited 2,817,911 12/1957 Owen et a1. 37-192 X 3,307,276 3/1967 Russcll 37192 X UNITED STATES PATENTS 3,006,087 10/1961 Lindell 37 192 x l/ 1913 Halle. 8/1936 Van Voorhis et a1. 37-83 5 ABRAHAM G. STONE, Primary Examiner. 4/1951 Ekenstam 3790 1/1952 Przybylskii ANTONIO F. GUIDA, Exammer. 2/1954 Askue 37-191 X A- E. KOPECKI, Assistant Examiner.