US2714773A

US2714773A - Stewart

Info

Publication number: US2714773A
Authority: US
Publication date: 1955-08-09
Anticipated expiration: 1972-08-09

Description

Aug. 9, 1955 s. STEWART 2,714,773

BLADE MECHANISM FOR ENDLESS TYPE DITCH DIGGER Filed Oct. 21, 1952 2 Sheets-Sheet l (Ittorneg Aug. 9, 1955 s, STEWART 2,714,773

BLADE MECHANISM FOR ENDLESS TYPE DITCH DIGGER 3moentor 5/0/VEY STEM/14197 United States Patent BLADE MECHANISM FOR ENDLESS TYPE DITCH BIGGER Sidney Stewart, Lincoln, Nehru, assignor of one-half to Peterson Construction Company, Lincoln, Nebn, a corporation of Nebraska Application October 21, 1952, Serial No. 315,914

3 Claims. (Cl. 37-86) line that is wider than the main wall portion of the foundation and provides a firm footing for the foundation. To obtain this it is customary to dig the entire trench of the width of the base and after the base is poured, to use a form of the proper width for the foundation Wall disposed longitudinally in the trench and supported above the base region, thereby providing a foundation of inverted T-shape. The vacant space on each side of the wall portion of the foundation is then filled in.

An object of this invention is to avoid the necessity for excavating this unused trench portion and for using forms for the pouring of the concrete. More specifically an object is to excavate a trench which is initially of the desired cross sectional shape with the relatively wide base and the wall portion of the trench above the base of the width of the foundation wall. Such a trench serves as its own form and the concrete may be poured directly into it.

The invention therefore provides an apparatus which by a single continuous operation makes an excavation that is of uniform width throughout the wall portion and widens out at the bottom or base portion. More particularly the invention provides means to cut an outwardly flaring portion on each side along the bottom of the trench.

The invention is particularly applicable to tractor excavators employing trailer excavating means of the bucket type operated by a chain on a pivotally suspended boom. In accordance with the invention suitable flaring cutters are provided on the free end of the boom which are oscillated by a power take-off, preferably from the chain, and make an undercut along the bottom on each side of the trench. The buckets are in the form of curved knives canted to constitute scoops which are disposed to collect the dirt removed by these flaring cutters and carry it out along with the dirt removed from the intermediate region.

The invention also includes certain particular features of construction and has other objects and advantages as will more particularly appear from the following description of the embodiment of the invention illustrated in the accompanying drawings, in which Fig. 1 is a side elevation of an apparatus embodying the invention;

Fig. 2 is a similar view on enlarged scale of the lower end portion of the boom as shown in Fig. 1 and illustrating the flaring knife and its operating means on one side;

Fig. 3 is an end View, partially in section, of the parts shown in Fig. 2;

Fig. 4 is an illustration of the mechanism for driving 2,714,773 Patented Aug. 9, 1955 the chain which carries the excavators and for raising and lowering the boom; and

Fig. 5 is a section through the finished trench containing the foundation wall.

Fig. 1 shows a more or less conventional form of tractor excavator with the improvements of this invention applied thereto. The tractor 1 contains the usual power unit 2 for propelling the tractor and driving the excavating mechanism. The excavator in the form of a boom is pivotally suspended from the rear of the trailer its free end being raised and lowered in the usual manner. The free end of the boom cuts its way into the earth to the desired depth of the trench and the digging continues at that depth as the trailing excavating means are moved along by the tractor.

The pivoted boom comprises an I-beam 3 which at its forward end is pivoted on a transverse shaft 4 extending between two suspension plates (one being shown) on the rear of the tractor and a sprocket chain 5 which carries the excavators runs over a sprocket 6 on the shaft 4 at the forward end of the beam and over an idler sprocket or roller 7 on a bearing shaft 8 at the free or rear end of the beam. The means for driving the sprocket 6 and for raising and lowering the beam are shown in Fig. 4.

The shaft 4 is an inner shaft and bears in a two part outer shaft comprising the sections 9 and 10 which bear in fixed bearings 11 and 12, respectively. The two sections of the outer shaft are disposed on opposite sides of the sprocket 6 and this sprocket is fixed on the inner shaft 4 which extends through the section 9 and has an extension beyond the sprocket which bears in the inner end of the section 10 of the outer shaft. A chain 13 driven by the power unit runs over a sprocket 14 on the outer end of the inner shaft 4 and drives the sprocket 6 and excavator chain 5.

The beam 3 is attached to the outer shaft sections 9 and 10 through two

hub brackets

15 and 16 which are welded or otherwise secured to flanges on a bracket 17 which is also welded to outer shaft sections 9 and 10 and has its flanges bolted to the web of the l-beam. The hub brackets have hub portions which fit upon and are welded to the inner ends of the outer shaft sections 9 and 16 on opposite sides of the sprocket 6. Thus the beam bears at its forward end upon the inner shaft 4 and in the fixed bearings 11 and 12.

The means for raising and lowering the boom are conventional and are shown only diagrammatically. A reversible motor (not shown) which is energized from the tractor battery drives and idler sprocket 18 through reduction gears in box 19 and this idler drives a leverage wheel 20 which is bolted on the outer shaft section 10. Thus the boom is raised or lowered at will merely by operating an appropriate switch for the motor circuit and the ratio of the reduction gears in the gear box is great enough to hold the boom rigid in any position.

The bearing shaft 8 and idler roller 7 are adjustable longitudinally of the beam 3 to control the tension of the chain 5. As shown, the bearing shaft 8 is mounted in the projecting ends of two

adjustable plates

21 and 22 disposed on opposite sides of the beam 3 and urged rearwardly by screws 23 (one being shown) which are threaded in bosses Welded on the beam faces and engage against the forward ends of the respective plates. These plates are shown as coupled by through bolts or rods, a slot in the web of the beam permitting of the adjustment.

The chain 5 also runs over two intermediate idler sprockets (not shown) carried by adjustable brackets 24 and'25, respectively, on the beam 3, the one sprocket engaging the lower run of the chain and the other the upper run. As shown these sprockets carry screw scrapers 26 and 27 respectively, on their shafts (one on each side of the trench) which are operated by the sprockets in the proper directions to scrape away from the sides of the trench the earth deposited by the chain driven excavators. These screws are standard construction and form no part (if the invention. i

1' For excavating, the chain carries digging means Which herein are called scooping means and which are in the form of twosets of arcuate knives disposed slightly at an angle with their leading edges out. The knives are arranged in right and left hand pairs, one set being the center knives 28 and cutting the center of the trench and the other set 29 being outside the center knives and cutting the sides of the trench. In practice there are four pairs of center cut knives and nine pairs of side cut knives, or twenty-six in all.

For the most part the mechanism above described is conventional. The invention resides in the means added thereto and combined therewith for digging an outwardly flaring bottom to the trench coincidently with the digging of the wall of the trench so that the excavation is made of the desired cross section by a single continuous operation.

The flaring bottom to the trench is dug by a pair of flaring knives which are pivotally mounted on the shaft 8 and are oscillated by power taken off from the chain 5. These knives are numbered 30 and 31 and are each bolted to an

angle plate

32 and 33, respectively, which are pivotally mounted on opposite ends of the shaft 8, being spaced from the idler roller 7 by spacer washers 34. As shown the idler roller has a bearing plate on each side and the two

adjustable plates

21 and 22 have each an outward bend beyond the end of the beam 3 which increases their spread sufficiently to receive the idler roller with its bearing plates between them. The spacer washers 34 are between these adjustable plates and the

angle plates

32 and 33.

These angle plates and the flaring knives carried by them are oscillated by a chain drivencrank and connecting arm mechanism which will now be described.

Bearing in

upstanding brackets

35 and 36 on the beam 3 some distance from its rear end is a sprocket 37. Fastened on the hub of the sprocket on the outer sides of the brackets are

crank discs

38 and 39, respectively, each having an eccentric crank pin 40 and 41, respectively, to which are pivoted connecting links 42 and 43, respectively. These connecting links are pivotally connected at their lower ends with the forward ends of connecting arms 44 and 45, respectively, the rear ends of which arms are connected, as by welding, to the angle plates 32 and r 33, respectively. Therefore the rotation of the crank discs raises and lowers the forward ends of the arms 44 and 45 and oscillates the flaring knives on their pivots as indicated by the broken lines in Fig. 2. The sprocket 37 meshes with andis driven by the chain 5.

The flaring knives have a circular cut-out on their rear edges and an inward extension 46 on their rear edges at the bottom. These extensions are deflectors to cut the bottom of the ditch smooth and to direct the earth cut out by the flaring knives into the scooping path "a of the outer knives 29.

Thus it is apparent that as the trailer is drawn along by the tractor, the knives carried by the chain will be removing the earth along the inclined surface marked X in'Fig. 1 to the full width of the wall portion 47 of the trench and foundation, and that the flaring knives meanwhile by their oscillation cut out the flaring sides 48 to the bottom of the trench, the deflector fingers 46 directing the earth removed by the flaring knives into the path of the knives 29. Thus the trench of the proper width and with the broader base is dug by one continuous operation, constituting a form ready to receive the concrete which when poured forms a foundation asindicated in Fig. 5.

As shown in Fig. 1 the screw scrapers are above the level of the ground. Their height will depend upon the character of the job and whether'it is necessary to remove all the dirt from the sides of the trench. Their adjustment lengthwise of the beam determines their relation to the ground level in the operating position of the boom.

It Will be understood that the boom first digs itself down to the desired depth for the trench, the initial end wall being arcuate with a flare at the bottom on each side and then will continue at uniform depth for the desired length, when the boom will be raised and the portion with the inclined bottom beyond the uniform depth portion of the finished trench will ordinarily be filled in. This of course avoids the necessity of digging a trench in the first instance of the full width of the base and using removable forms for the wall portion and later filling in outside of the wall portion.

While a specific construction has been illustrated and described for accomplishing the desires purpose, it will be understood that this is illustrative merely and that the invention may be otherwise embodied as will readily occur to those skilled in the art within the scope of the invention as defined in the following claims.

What is claimed is:

1. A trenching mechanism comprising in combination with tractor power mechanism having rear attaching means, a beam pivoted at one end to the rear attaching means of the tractor and having its other end free, a supporting roller pivotally mounted upon the beam near each end thereof, a chain running over the rollers and driven by the power mechanism, scooping means carried by the chain and operative to excavate a trench, a pair of outwardly flaring cutting knives, one knife being pivotally mounted on each side of the free end of the beam, each knife having a forwardly directed cutting edge intersecting the plane of the respectively adjacent side wall of the trench excavated by the scooping means and extending obliquely outwardly and downwardly beyond said side wall to the plane of the bottom of said trench, an eccentric carried by the boom and operatively related to the chain, crank means carried by the boom and operated by the chain, and connecting means between the crank means and the knives and operative to oscillate the knives.

2. A trenching mechanism as defined in claim 1 in which the flaring knives have inwardly curved bottom portions trailing said cutting edges for directing the dirt loosened by the knives into the path of the scooping means.

3. A trenching mechanism as defined in claim 1 in which the crank operating means for eachknife comprises a sprocket supported in bearings on the beam intermediate its ends and operatively engaging the chain, a crank on the sprocket, and a connecting lever arm between the crank and knife operative to oscillate the knife.

References Cited in the file of this patent UNITED STATES PATENTS 844,959 Rockford Feb. 19, 1907 1,214,410 Bauer Jan. 30, 1917 1,400,712 Bager Dec. 20,1921 1,411,018 Hammen Mar. 28, 1922 1,684,869 Krueger Sept. 18, 1928 1,858,727 Bentson May 17, 1932 2,519,077 Schmidt Aug. 15, 1950