US2223485A - Countersink - Google Patents

Description

Dec; 3, 1940. c EVELETH 2,223,435

) COUNTERS INK Filed Oct. 16, 1939 G'flZEveZeZiZ/ INVENTOR.

ATTORNEYS.

Patented Dec. 3, 1940 UNITED STATES PATENT OFFICE COUNTERSINK Clarence M. Eveleth, River Forest, Ill.

Application October 16, 1939, Serial No. 299,747

' 4 Claims. (Cl. -123) This invention relates to a tool comprising a stop and a countersink member journaled in the stop, the stop limiting the amount that the countersinkilng member enters the .material. The present invention aims to provide novel means whereby the stop will be prevented from marring finely finished surfaces.

It'is within the province of the disclosure to improve generally and to enhance the utility of devices of that type to which the present invention appertains.-

With the above and other objects in view, which will appear as the description proceeds, the invention resides in the combination and anrangement of parts and in the details of construction hereinafter described and claimed, it being understood that changes in the precise embodiment of the invention herein disclosed, may be made within the scope of what is claimed, without departing from the spirit of the invention.

In the drawing:

Fig. 1 shows in elevation, a device constructed in accordance with the invention, parts being broken away;

Fig. 2 is a bottom plan;

Figs. 3, 4 and 5 are diagrammaticelevations illustrating the operating of the device which characterizes this application.

The numeral I marks a tubular casing provided at its lower end with a foot 2 whereon a sleeve 3 is secured by threading, the sleeve being provided at its lower end with an inwardly extended, annular flange 4. The numeral 5 designates a tubular stop, having a head 6 received between the flange 4 of the sleeve 3 and the foot 2 of the casing I, the construction being such that there can be relative movement between the casing and the stop, so far as rotation is concerned. I v

The numeral I marksa countersink bit extended through the casing I and the stop 5, the bit having a working end 8. The countersink bit I is threaded at 9 into the casing I, for adjustment, to determine the amount that the working end 8 of the bit projects downwardly beyond thelower end of the stop 5, and to determine the depth of the countersink. After the countersink bit I has been adjusted longitudinally with respect to the casing I, the countersink bit is held in its adjusted position, by means of a jamb nut Ill engaged with the threads 9 of thecountersink bit and engaging the upper end of the casing I. The part I I is a knurled collar formed on the casing I, whereby the casing can be held against rotation whilst the jamnut I0 is being tightened up.

After the desired longitudinal adjustment of the countersink bit I has been attained, and the jamb nut Ill set against the end of the casing I,

the casing I and the bit 'I turn as one piece.

Grossly considered, the device as thus far described comprises a countersink tool, including both the casing I and the bit I, and a tubular stop, to wit, the part 5, the stop and the countersink tool being connected together for relative rotation.

Generally stated, the countersink tool, including the bit I and the casing I, is rotated and the working end B of the bit forms a countersink in the material. The depth of the countersink is determined when the lower end of the stop 5 comes into contact with the material. Such a combination of parts, and the resulting operation, are reasonably satisfactory if rough material is being countersunk. If, however, a finely finished or polished material is being countersunk, it will be damaged or marred by contact with the lower end of, the stop 5. This invention aims to provide a simple but effective means whereby such a contingency will be avoided.

The stop 5 is provided at its lower end with circumferentially spaced fingers I2. In the lower end of each finger I2, and at one side thereof, a rectangular recess I4 is formed. A bore I5 in the finger I2 leads upwardly from the lower end of the finger, past the recess, A cushion I6 is secured in the bore. I5, and, preferably, is a cylindrical rubber plug. The plug I5 is long enough so that inits normal condition, it projects downwardly below the lower end of the finger I2, as Fig. 3 will show. The upper wall of the recess I4 is rounded, as shown at IT. This is done to the end that when the lower end of the plug I5 is flexed laterally, as in Figs. 4 and 5, the plug will not be cut. In the upper wall of the recess 4, a circumferentially extended groove I8 i formed, the groove being shaped to correspond. with the cross sectionof the plug I6.

In practical operation, the countersinking tool 'I-I'is rotated, and the working end 8 of the countersink bit I forms a. countersink in the material. When the finger I2 is rotated in the direction of the arrow A in Fig. 3,'the lower end of the plug I6 comes into contact with the material. The problem presented at this stage is to stop the rotation of the member 5, under the drag of the'countersinking tool. That is done by pressing the tool down, as shown by the arrow B in Fig. 4, until the lower end of the plug it is 55 brought into close frictional contact with the work. .The lower end 01 the plug it retires into the recess l4, and is held against lateral swingingmovement, because the lower part oi. the plug is received in the groove 18.

The rotation of the stop 5 now has been terminated, the parts being in the position of Fig. 4, but that is not enough. The tool must be pressed downwardly, in the direction of the arrow C in Fig. 5, until the lower end of the finger l2 comes into contact with the work. That contact determines positively, the depth of the countersink formed by the working end 8 of the bit 1. brought into contact with the work the depth of the countersink could not be determined deflnitely, because the plug 16 is compressible.

The recess l4 exercises two functions. It provides a space into which the flexed lower end of the plug l6 can retire, as in ,Fig. 4. Moreover, since the lower end of the'plug It does not have to be compressed throughout its entire cross section, it is not difllcult to bring 'the finger I2 claimed is:

1. In a device of the class described, a rigid material-engaging stop having a bore at its lower end, a countersink tool journaled in the stop,

and a compressible, material-engaging cushion carried by the bore in said stop and projecting If the lower end of the finger l2 were not below the lower end of the stop, the stop being provided at its lower end with a. recess leading into said here and into which the cushion can retire when flexed laterally, the depth of the recess being less than the diameter 01' the cushion.

2. In a device of the class described, a rigid material-engaging stop having a bore at its lower into said bore and into which the cushion can retire when flexed laterally, the depth of the recess being less than the diameter of the cushion, and the stop being provided, at the upper wall of the recess, with a circumferentially extended groove, receiving a portion of the cushion.

3. In a device of the class described, a rigid 2| material-engaging stop having a longitudinal bore and a lateral recess in its lower end, the

recess leading to the bore, a compressible, ma-

terial-engaging cushion mounted in the bore and projecting beyond the lower end of the stop, the 2:

. heightfoi' the recess being less than-the diameter or the cushion, the cushion being laterally flexible to enter the recess, the stop being rounded at the place 01'- juncture between the, recess and the bore, to prevent the cushion from being cut whenflexed, and a countersink tool jouma-led in the stop and extended downwardly below the' stop. I 4. A device a circumferentially extended groove, located in the upper wall of the recess, and shaped to receive the flexed cushion.

of the class described, constructed as set forth in claimxli and wherein the stop has

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