US 2912228 A
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Nov. 10, 1959 c. w. KANDLE 7 2,912,228
DRILL HEAD FOR WING CUTTERS Filed July 5, 1957 2 Sheets-Sheet 1 INVENTOR. CHARLES W. KANDLE' ATTORNEYS Nov. 10, 1959 c. w. KANDLE DRILL HEAD FOR WING CUTTERS '2 Sheets-Sheet 2 Filed July 5, 1957 /"L" WW4! 1NVENTOR. CHARLES w. KANDLE flilag lewlum ATTORNEYS United States Patent DRILL HEAD FOR WING CUTTERS Charles W. Kandle, La Grange Park, Ill.
Application July 5, 1957, Serial No. 670,275
1 Claim. (Cl. 255-76) This invention relates to drilling apparatus and more particularly to drill head's having wing'cutters thereon. I
In drilling vertical holes in the earth for the installation of caissons, large diameter concrete pipes, on the order of 48 inches, for example, are inserted in the hole immediately after the drill head. The drill drive shaft extends through the concrete pipe and when the hole is completed the drill head is withdrawn back up through the pipe. The drill head, must cut a hole of larger diameter than the outside diameter of the pipe to permit the latter to be inserted after the drill head and as it progresses through the earth. Therefore, wing cutters are employed on the drill head which extend radially outwardly beyond the outer surface of the pipe, which often have a wall thickness of 6 inches. These wing cutters ream the hole clean so as to prevent binding of the pipe as it follows the drill head in the earth.
When the drilling operation is completed, the wing cutters are retracted as the drill head rotation is reversed and the drill unit can then be pulled back through the pipe.
When drilling as above described, it will be appreciated that considerable weight of the drill unit is placed on the drill head and on the wing cutters. It has been found that the resulting pressure between the bottom of the hole and the drill head has caused the wing cutters to bind and prevent their swinging to a fully extended cutting position.
In accordance with this invention there has been provided a drill head including wing cutters which eliminates any binding of the cutters and thereby insures proper operation thereof.
Other advantages of the invention will appear hereinafter as this disclosure progresses, reference being had to the accompanying drawings in which:
Figure 1 is a vertical sectional view through a hole being dug by a drill head embodying the invention;
Figure 2 is a perspective view of a drill head made in accordance with the invention, taken generally from the bottom of the head, and showing the wing cutters in the cutting position;
Fig. 3 is a bottom view of the head with the cutters in the contracted position and shown in the cutting position in broken lines;
Fig. 4 is a perspective view of the top side of the head shown in Figure 2;
Fig. 5 is a fragmentary view of a portion of the head, taken from the bottom side thereof and on an enlarged scale to show the recess for the cutter which is shown dotted in the contracted position;
Fig. 6 is a side view of the recessed plate portion taken along line 6-6 of Figure 5; and
Fig. 7 is an elevational sectional view showing a cutter mounted on the drill head, taken generally along line 77 of Figure 4, but with the cutter in the extended cutting position and on an enlarged scale.
Referring more particularly to Fig. 1 of the drawings, a large hole 10 has been drilled in the ground 11 by the drill unit 12. The drill unit is secured to a drive shaft 2,912,228 Patented Nov. 10, 1959 are inserted in the hole fromthe top, forcing pipe 15 further into the hole.
Only two wing cutters 18, 19 are shown on the drill head of Fig. 1, but any number may be used and they would be spaced circumferentially around the drill head 16. The cutters are adapted to pivot relative to head 16 to a position with the outer edge thereof extending radially beyond the outer diameter of the pipe so as to form a hole slightly larger than the pipes outside diameter. The drill head is of lesser diameter than the internal diameter of the pipe so as to permit withdrawal of the head through the pipe when the cutters have been retracted as shown in Figures 2 and;3.
The drill head 16 shown in Figs. 2 and 4 is comprised of a circularly shaped heavy steel plate 17 having diametrically opposed segmental openings 20, 21 therein. Along the trailing edges 20a and 21a, respectively, of these openings are a series of teeth 22 which cut the bottom of the hole and a pilot drill 23 is located at the center of the head.
Four wing cutters 24 to 27 have been shown in Figures 2, 3 and 5 and each comprise 2 spaced apart parallel arms 28, 29 shown most clearly in Fig. 7. The arms have axially aligned apertures 30 by which they are pivoted on pin 31 extending through a mating aperture 32 in plate 17. The arms 28, 29 are connected together at their other end by the cutter blade 33 welded thereto.
The periphery of plate 17 is provided with angularly spaced cut away portions 34a as shown best in Fig. 5 to receive the individual cutters Within the diameter of the plate when the cutters are in the retracted or non cutting position. The leading edge 34 formed by the cut away portion acts to limit the inward swinging of the cutter.
Adjacent the trailing edge 35 of each cut away portion 34a and on the trailing or top side 17a of the plate 17 a reinforcing plate 36 has been welded. This plate serves compensate in strength for the recess 37 which has been cut from the opposite or leading side 17b of plate 17 adjacent to trailing edge 35. In addition the plate 36 permits the use of standard width cutters. That is to say, the distance between the arms 28, 29 of the cutters is such as to permit the arms to slide over the plates 17, and 36 to permit free swinging of the cutters. The arms are held against twisting when cutting by the plates therebetween. Thus, a rigid cutter is provided which will not twist in use.
Rearward swinging of the cutter is limited by the cutter blade striking the trailing edge 35 of plate 17 and when cutting occurs a rigid thrust absorbing support is thus provided for the blade.
The lower end of the pin 31 has a flat head and the pin has a keeper 38 through its other end to hold it captive in the aligned apertures 30, 32.
With this particular recessed mounting of the cutters to the head, a cutting head assembly has been provided which is substantially flush across its bottorn side in regard to the wing cutters. Stated otherwise, the wing cutters do not extend beyond the lower surface of plate 17 and relative movement therebetween is assured to enable the cutters to swing freely to the extended cutting position when desired. By use of the reinforcing plates 36 standard width cutters can be used without using a head plate 17 having increased thickness over its entire area corresponding to the thickness of plates 36. K
By recessing the wing cutters into the lower surface of the head, the Weight of the drill unit does not rest on the cutters and therefore the latter will not bind or be retarded in their movement. The outermost edge 33a of the cutter blade may extend slightly beyond plate 17 to provide a small blade area for engaging uncut spoil and thereby initially swing the cutter outwardly into cutting position.
It may be desirable to make a preliminary hole with a tapered drill before using the drill disclosed here for the reason that a tapered drill has faster cutting characteristics. The drill head of this disclosure is very efficient in reaming such a hole and for the finishing operation therefor.
Various modes of carrying out the invention are contemplated as being Within the scope or" the following claim particularly pointing out and distinctly claiming the subject matter which is regarded as the invention.
In a Wing cutter earth drilling head having a rotary plate-like body with an open segment for the passage of spoil upwardly therethrough; a peripheral recess in the outer edge of said body for receiving a wing cutter blade; a second recess in the lower surface of said body and extending along and beneath the trailing edge of said peripheral recess and radially inwardly therefrom; a Wing cutter comprising a cutting blade having its cutting edge extending radially outward of the periphery of said body, and a cutter support carrying said blade and having upper and lower arms extending radially inward therefrom, the lower arm being disposed in said recesses and the upper arm being spaced above said body; a reinforcing plate portion integral with said body and being disposed on the top of said body in the area coextensive with said sec- 0nd recess to prevent distortion of the body bounding said second recess; and a pivot pin passing vertically through said body and reenforcing plate portion and pivotally securing the upper and lower arms of said wing cutter thereto at the inner end of said second recess.
References Cited in the file of this patent UNITED STATES PATENTS 146,752 Considine Ian. 27, 1874 147,323 Hanson Feb. 10, 1874 1,052,847 Repp Feb. 11', 1913 1,858,263 Charlton May 17, 1932 1,881,101 Spaulding Oct. 4, 1932 2,000,195 Siebel May 7, 1935 2,688,465 Birdwell Sept. 7, 1954