US1960905A

US1960905A - Pilot for valve seating cutters

Info

Publication number: US1960905A
Application number: US567462A
Authority: US
Inventors: George M Graham
Original assignee: Kent Moore Organization Inc
Current assignee: Kent Moore Organization Inc
Priority date: 1931-10-07
Filing date: 1931-10-07
Publication date: 1934-05-29
Anticipated expiration: 1951-05-29

Description

May 29, 1934.

G. M. GRAHAM PILOT FOR VALVE SEATING CUTTERS Filed Oct. 7, 1931 I! 8 I I v I: I:- 11 t INVENTOR eavyew. 6722 ATTO RNES- Patented May 29, 1934 George M. Graham, Detroit, Mich, assignor to Kent-Moore Organization, Detroit, Mich, a corporation of Michigan Application October 7, 1931, Serial No. 567,462

1 Claim.

This invention relates to aligning pilots and more particularly to such devices especially adapted for use in connection with cutting tools for forming valve seats of internal combustion engines and other devices where great accuracy is required.

An object of the invention is to provide a pilot of simple construction which is cheap to manufacture, accurate in operation and easy to manipulate, and wherein the construction is such as to make the device self expanding, automatic and accurate in alignment, and that may be readily and quickly inserted in a valve stem guide to accurately hold and guide a valve seat cutting tool during the forming or re-forming oi the valve seat.

With the above and other ends in view, the invention consists in the matters hereinafter set forth and more particularly pointed out in the appended claim, reference being had to the accompanying drawing in which- Figure 1 is a side elevation of the pilot de- .tached and shown partly in longitudinal section;

Fig. 2 is a transverse section substantially upon the line 2-2 of Figure 1;

Fig. 3 is a view similar to that of Figure l and showing a slightly modified construction;

Fig. 4 is an end elevation of Figure 3; and

.Fig. 5 is a View of a portion of an engine in section, and illustrative of the manner in which the pilot embodying the present invention is adapted to be used in re-forming the engine valve seat by means of a suitable cutting tool guided by said pilot.

In forming or re-forming the valve seat 1 of an internal combustion engine, this seat must be in exact axial alignment with the valve stem guide 2, as otherwise the valve would not properly seat, and to insure such accuracy a pilot is inserted in the bore of the valve stem guide with its upper end portion projecting upwardly through the opening in which the seat is formed and in exact axial alignment with said opening so that a cutter 3 may be sleeved upon this portion of the pilot and will be held and guided thereby concentric with the valve seat during the forming operation, said cutter being freely rotatable upon said pilot and arranged to be "rotated by means of a suitable handle member i sleeved over the upper end of the pilot and engaged in any suitable manner at its lower end, with said cutter, to turn the same. 7

Pilots for this purpose are commonly made for insertion in the valve stem guide and provided with means adjacent their inner ends for expanding the same within the bore of said guide to center the pilot within said bore, but such expanding means is usually operated by the mechanic through the medium of a member extending through an axial bore in the pilot and through the upper end thereof. The pilot is thus complicated and weakened in its construction, and care is necessary in placing and expanding such a pilot.

The pilot embodying the present invention and as shown in Figures 1 and 2, comprises a rod which is turned to the proper diameter throughout the upper end portion 5 thereof, to fit the axial bore of the cutter 3 which, in the operation of the device, is sleeved upon this end portion of the pilot, free to turn thereon, after the pilot has been inserted in the valve stem guide. The lower end portion 6 of this pilot rod is turned down to a diameter considerably less than the internal diameter of the valve stem guide 2, and connecting these

portions

5 and 6, is a portion 7 formed tapering or conical to engage within the upper end of the bore of the valve stem guide and seat against the inner edge thereof to accurately center the upper end of the portion 6 within said bore.

To provide for the accurate centering of the lower end of the portion 6 within said bore and thus co-act with said taper 7 in holding the portion 5 of the pilot in exact axial alignment with the axis of the valve stem guide, said end portion 6, adjacent its lower or inner end, with a bulge or enlargement 8 which, at its line of largest diameter, is of greater diameter than the internal diameter of the bore of the valve stem guide, and this enlargement is preferably tapered longitudinally of the end part 6, each way from the largest part of said enlargement. The end or part 6 is bored axially inward from its free end as at 9 to a point beyond said enlargement 8, and that part or" the tubular end thus formed and which is formed with the enlargement 8, is split or slotted longitudinally at any desired number of places around the tube as at 10, thus dividing the tube into yieldable portions or fingers, which, when this tubular end is forced endwise into the bore of the valve stem guide bringing the enlargement 8 into contact with the wall of said guide, will yield inwardly. These yieldable portions thus firmly press the enlarged portions thereof into firm yielding contact with the wall of the bore of the valve stem guide and accurately center this inner end of the pilot within said bore. The inner end of the pilot is thus made self expanding and centering, so that it is only necessary for the mechanic to force the pilot endwise into place, and it may be removed in a like manner without other manipulation, relieving the mechanic from the necessity for manually or care in centering and expanding the pilot.

In Figures 3 and 4 a slightly modified construction of pilot is shown in that the slits 10 dividing the tubular end of the pilot, are cut through the end of the tube as shown at 11, thus making the spring fingers or divisions more yielding than where these slots do not extend through the end, as in Figures 1 and 2. Obviously other changes may be made within the scope of the appended claim, and such changes are contemplated.

Having thus fully described my invention, what I claim is:

A self positioning pilot for a valve seat cutter for use in combination with a valve seat and a bore co-axial with the valve seat and forming a valve stem guide, comprising a rod adapted to receive a cutter and rotatably support the same, said rod being of larger diameter than said bore, a tubular end portion of lesser diameter than said bore, a conical portion connecting said rod and tubular end portion and adapted to seat within the upper end of said bore, said tubular end portion being formed intermediate the ends thereof with an arcuately tapering enlargement, said enlargement at its largest part being of greater diameter than said bore, said enlargement being slitted throughout the length thereof radially and longitudinally to provide portions to yield inwardly upon insertion of said enlargement within said bore and frictionally engage the wall of the bore.

GEORGE M. GRAHAM.