US2541537A - Undercutter - Google Patents

Description

Feb. 13, 1951 G. w. NEwcoMB UNDERCUTTER 2 Sheets-Sheet l Filed July 22, 1946 INVENTQR.

ATTDRNEYS Feb, 13 1951 G. w. NEwcoMB 2,541,537

UNDERCUTTER Filed July 22, 1946 2 Sheets-Sheet 2 QJ /I l "6 J @a J3 711.9 g3 J? .9/ i T-. J3 J6 5 2? I les' 1 j .93 Zoy? V Il'f/ lm W f IN VEN TOR.

ATTE] RN EYE Patented Feb. 13, 1951 UNITED sTATEs lPATENT OFFICE UNDERCUTTER George W. Newcomb, Baltimore, Md. Application July 22, 1946, Serial No. 685,444

2 Claims. 1

This invention relates to a socket cutter, and it is one object of the invention to provide a cutter by means of which sockets may be .formed in furniture and the like to receive ends of dowel pins, chair rounds, bars, and the like, the socket being so cut that it increases in diameter towards its inner end, and thus allows the end of a dowel pin driven into the socket to be spread by a wedge deposited in the socket and firmly held against dislodgement from the socket,

Another object of the invention is to provide an under-reamer with cutters which are nor* mally in a retracted position allowing the underreamer to cut its way into the wallfof a previously bored hole in a chair leg or the like and form a socket, means being provided for guiding the cutters outwardly and enlarging the socket after the hole has been cut to a predetermined depth.

Another object of the invention is to provide an under-reamer with cutters which rare slidable longitudinally of the under-reamer in grooves formed therein, lower portions of the grooves having sloping surfaces acting as cams for guid-y ing the cutters outwardly when the cutters are forced downwardly.V Another object of the invention is to provide actuating means for expelling the cutters consistingof a collar loosely mounted about the under-reamer, and yieldably held in a raised position by a spring which maintains the collar in contact with cams of a lever pivoted to a second collar. It will thus be seen that after a socket has been started, the lever may be swung downwardly, and the cams will apply pressure to force the cutters outwardly. n

Another object of the invention is to provide an under-reamer having socket enlarging means associated with it, which is o'f simplev construction and easy to operate.

The invention is illustrated in the accompanying drawings wherein:

Figure 1 is a side view of the improved drill with the auxiliary cutters in a retracted position;

Figure 2 is a side View showing 'the auxiliary cutters extended to form a socket gradually increased in diameter toward the inner end;

Figure 3 is a fragmentary view showing a cam of modified formation;

Figure 4 is a view looking at the lower end of the under-reamer with the auxiliary cutters retracted;

Figure 5 is a view similar to Figure 4 showing the auxiliary cutters extended;

Figure 6 is a view showing the under-reamer in longitudinal section with the auxiliary cutters retracted;

Figure 7 is a view similar to Figure 6 showing the auxiliary cutters extended;

Figure 8 is a sectional view 8 8 of Figure '7;' t

Figure 9 is a sectional view takenalong line 8-9 of Figure 6;

Figure 10 is a sectional View taken along line lG-Iof Figure 6;

Figure l1 is a side View of an end a dowel;

Figure 12 is an end view of the dowel;

Figure 13 is a Viewl showing the dowel fitted into a socket and its inserted end expanded; f

Figure 14 is a view taken along line Ill-I4 of Figure 13;

Figure 15 is a view of a wedge by means of which the dowel pin is spread.

The improved under-reamer constituting the subject matter of this invention is used for cutting sockets to receive dowel pins, chair rounds, or the like. When a drill of conventional con, struction is used, a socket yis formed which is of an even diameter throughout its depth, and even if a Wedge is placed in the socket to spread the end of a dowel pin or round, a permanent mounting will not be obtained, as the dowel' pin may work loose and slip out of the socket.

The under-reamer l may be of any desired length and diameter, and when in use is mounted in a drill chuck 2. The lower end of the underreamer may be formed with cutting teeth or the under-reamer sharpenedin any manner desired so that when the underi-reamer is turned in a previously bored hole A, a socket 3 will be formed in a board, chair leg, orthe like 4. Groovesf extend longitudinally of the under-reamer and each has its lower 'endg portion gradually; decreased in depth to forma cam surface 6 extend'- ng downwardly at anoutward incline as shown in Figures 6 and 7. Auxiliary cutters 9 are slidably mounted in the grooves or recesses 5, and

taken along line portion .of

each cutter has its lower portion -9 extending`y downwardly at an outward incline and its upper end formed with an outwardly extending linger Il. The fingers ll engage in sockets I2 formed in a collar I3 which ts'loosely about the underreamer and is slidable along the under-reamer from the raised position shown in Figure 6 to the lowered or depressed )position shown in Figure "l, A sec-ond collar ,I4 ts about the under-reamer, where it is secured in predetermined spaced relation to the lower end thereof, and upon this `which has its upper end bearing against the under surface of the collar I3 so that the collar I3 will be urged upwardly to the raised position. Spaced upwardly from collar I 3 is a ring or collar I8 secured by a pin I1 which passes transversely through the under-reamer, and between the ring I6 and the collar I3 is a sleeve I8. The sleeve I8 is free upon the under-reamer, and carries pins I9 which pass through the forks for arms 20 of a lever 2I and pivotally mount 'the lever. Cams 22 project from the arms of the lever or handle 2I and the curved lower edge faces of the cams bear against the upper surface of a wear ring or disk 23 which rests upon the collar I3. When the handle is swung downwardly, the collar I3 will be moved downwardly with it, and as the collar moves downwardly, 'the cutters 3 will ,be shifted downwardly in the grooves and their lower ends'gradually shifted outwardly bythe cam surfaces 6. Therefore, aft-er a socket has been cut to a desired depth, the auxiliary cutters may be gradually moved outwardly anda. socket will be formed of gradually increasing diameter toward its inner end. A dowel pin or chair round 24 formed with crossed slits 25 leading from its end will be driven into a socket after a cross-shaped wedge 26 has been deposited rin the socket, and as the arms of the wedge enter the slits `25, the dowel pin or round will be spread and firmly anchored in the tapered socket as shown in Eigure 13. lInstead of providing arms of the handle 2'I with cams 22, cams 21 of 'substantially elliptical or oval shape may be mounted upon end `portions of the ipins I9 inwardly of the arms of the lever or xedly secured to the "lever arms to turn therewith. Such cam plates 'are wshown in Figure 3, and referring to this Figure, it will be seen that bearing balls 24 may be provided between the disk 23 and the collar I3, land thus form a bearing for the collar. A similar bearing is provided above the cam plates and consists of a disk 25 and 'bearing balls 25. With an under-reamer of the improvedr construction, vsockets may be quickly cut and be either of an e'vendiameter or tapered toward their outer ends so that dowel pins driven into the sockets will 'be wedged in vthe sockets 'and very rmly held against displacement from 'the sockets.

Having thus described the invention, what is claimed is:

1. `An under-reamer comprising a substantial- Iy cylindrical shank formed with longitudinally extending grooves spaced from each other lcir cumferen-tially of the shank, and having their lower end portions gradually decreased in depth to provide cam surfaces extending downwardly 'at an outward incline, cutters having vcutting edges slidable longitudinally in said grooves and having their lower portions extending at an outward incline, fingers extending from upper ends of said: cutters and projecting radially from the shank, a collar loose about said shank and formed with sockets into which the fingers 'fit to connect the cutters with the collar, a second collar secured about the lower end 'portion of the shank adjacent to the upper edge of the cam surface of the grooves and engaging the edge surface of the cutters whereby to cam them inwardly as they are moved upwardly on the shank, a helical spring surrounding the shank between the collars and urging the rst collar upwardly to a raised position for holding the cutters re- -tracted, a ring secured about said shank above the first collar, a sleeve fitting loosely about the shank between the rst collar and said ring, pins projecting from opposite 'sides of vsaid sleeve, a lever having arms at its lower end pivoted upon said pins, and cam members extending from said arms and having curved lower edges engaging the .rst collar for forcing the same downwardly and cause the cutters to be shifted downwardly in the grooves and gradually moved outwardly to an extended position by engagement with the cam surfaces at lower ends of the grooves and the depth vof the grooves being so that the cutters will not project beyond the shank in their uppermost position but will project beyond theshank in 'their lowermost cutting position.

2. An under-reamer comprising a substantially cylindrical shank formed with longitudinally extending grooves, having lower portions provided with outwardly sloping cam surfaces, cutters having cutting edges slidable longitudinally in said grooves and having lower end portions extending outwardly at an incline, and moved to an extended position by Aengagement with the cam surfaces when the cutters are shifted downwardly in the grooves, and the depth. of the grooves being so that the `cutters will not project beyond the Ashank in their up-A per-most vposition vbut will project beyond the shank in their lowermost .position an abutment about the lower portion of said shank adjacent to the upper edge of the cam surfaces of cthe grooves and engaging the edge surface of the' cutters whereby to cam them inwardly as they are moved upwardly on the shank, a collar loose about the shank above the abutment, a spring about the shank between the abutment and the collar and urging the collar upwardly, said cut ters having their upper ends connected with the collar and being` held in a retracted position when the collar is in its raised position, a ring secured -about the shank above the collar, a sleeve about the shank between the collar and thev ring, and a lever having arms pivoted to op-l posite sides of the sleeve and provided with 'cams acting upon the collar to force the collar down-z wardly and Vshift the cutters to an extended position when the lever is swung downwardly.

GEORGE W. NEWCOMB.-

REFERENCES CITED The following references are of record in ther iile Vof. this patent:

Huelster May 28, 1946

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