US2446787A - Pilot guide device - Google Patents

Description

ug. l0, i948. H. H. REETZ.

PILOT GUIDE DEVICE` Filed DeG. 5, 1945 I rzventor By QM @d/wey Hmm Patented Aug. 10, 1948 r'rsnr i oFFics 2 Claims.

This invention relates to a device for guiding the expansble pilot of a valve seat grinder or reamer when used in an engine block having spaced upper and lower portions formed with vertically aligned cylindrical valve stem and tappet guide openings.

The primary object of the present invention is to provide a guide `device of the above kind by means of which the valve seat may be ground or reamed in perfect alignment with the valve guide and tappet without the exercise of special skill or care.

A further object of the invention is to provide a device of the above kind which is extremely simple in construction, easy to use, and highly efcient in use.

The exact nature of the present invention will lbecome apparent from vthe following description when considered in connection with the accompanying drawing, in which:

Figure l is a sectional View showing a device constructed in accordance with the present invention and illustrating the same in use in conu nection with a Valve seat grinder.

Figure 2 is a perspective view of the elongated tubular member or bushing forming part of the present guide device.

Figure 3 is a horizontal section taken on line 3- 3 of Figure 1.

Referring in detail to the drawing, 5 indicates the cylinder block of an internal combustion ongine having spaced upper and lower portions 6 and l, the upper portion vI5 being formed with a valve seat 8 and a valve stern guide opening 9 below and in alignment with the seat 8, and the lower portion i being formed with a guide opening iD for a tappet II in vertical alignment with the opening 9 and seat 8.

In resurfacing the valve seat 8, it is the customary practice to use a reamer or a grinder. The reamer and grinder are of generally similar construction except that the former uses a reaming head and the latter uses a grinding stone. In Figure l, the present guide device is shown in use in connection with a valve seat Kgrinder which includes a tubular shaft I2 having a grinding stone It secured on the lower end thereof. The grinder further includes an expansible pilot ernbodying an elongated sleeve I4 whose upper end portion is rotatably received within the shaft I2, and which has an axial bore in which is disposed an expander rod I5 having a threaded upper end portion I6 and a tapered lower end portion I'I. The sleeve I4 is internally threaded at its upper end to receive the threaded portion I6 of the rod I5, so that by turning the latter, said rod is adjusted axially of the sleeve I4. The upper end of the rod I5 may be provided with an ex tension formed with a polygonal socket I8 to facilitate rotation of the rod I5 by the use of a suitable tool. The lower end portion of sleeve it is provided with slits I9 arranged around the circumference and extending upwardly from the lower end. The slitted lower end portion of sleeve I4 is tapered inside to fit the tapered lower end I'I of the rod I5, so that when the rod I5 is adjusted downwardly the split lower end por tion of sleeve I4 will be expanded. Conversely, when rod I5 is adjusted upwardly, the split end portion of sleeve I will contract under its own tension. Intermediate its ends, the sleeve Mi has an enlarged tapered portion 20.

The guide device embodying the present invention includes an elongated tubular member or bushing 2l. Having an enlarged cylindrical upper end portion 22 adapted to snugly fit in the valve stem opening S, and a tapered lower end 23 adapted to simultaneously center in the tappet guide opening IIJ while resting on the lower block portion 1 about said opening Il). The tubular member 2l has an axial cylindrical bore 2li for snug sliding reception of the split end portion of the pilot when contracted, and it is noted that the lower end portion of the bore 2li is downwardly iiared as at 25. A helical compression spring 26 may be disposed on the upper end of the member or bushing 2|, said spring having a bushing 21 fitted and secured in the upper end thereof and adapted to have a snug sliding i'it on the sleeve I4 above the enlarged portion 20. The spring 26 is of a length so that it will be placed under compression when the member 2l is operatively disposed as shown in Figure 1 and the grinding stone of the grinder or the reaming head of the reamer is forced downwardly against the Valve seat 8, the bushing 21 being in contact with the bottom of said grinding stone or reaming head. This compression of spring 26 will firmly hold the member or bushing 2| in place with its lower end 23 in rirrn contact with the block portion 'I and centered in the tappet guide opening I0. Thus, when the grinding stone or reaming head is rotated, the valve seat will be reamed or ground in perfect alignment with the valve guide and tappet.

In practice, the tubular member or bushing 2i is inserted downwardly through the opening surrounded by the valve seat 8 and lowered until the end portion 22 is disposed in the valve guide opening 9 and the tapered end 23 is centered in the tappet guide opening I at the top of the latter. The pilot is then inserted so that it has its lower end portion disposed within the bore 24 of the member or bushing 2| and the enlarged tapered portion 2U of sleeve I 4 is centered in the bore 24 at the top of the member or bushing 2l as shown in Figure 1. The rod I5 is then rotated to feed the same downwardly and thereby expand the split lower end portion of sleeve I4 into tight gripping engagement with the wall of the bore 24. If the spring 26 is used, it is then placed upon the top of the member or bushing 2l about the portion of the sleeve I 4 directly above said member or bushing 2|, Whereupon the grinding stone or reaming head is brought down into engagement with the valve" seat 8 by allowing the upper end portion of theV sleeve I4 to enter the tubular shaft I2. When this is done, the spring 26 is placed under compression as and for the purpose previously described. The grinding stone or reaming head is then rotated by turning the shaft I2 so as to effect the desired valve seat resurfacing operation. If desired, the spring 26 may be -dispensed with because there is often sufficient space between the block portions 6 and I to permit gripping of the member or bushing 2| for the purpose of firmly holding it in place with its lower end centered in the tappet guide opening I0. Should the tappet I-I be in a raised position projecting above the block portion 1, its tapered upper end 28 will enter the flared lower end portion of bore 24 so as to have the same` supporting and centering effect on the lower end of the member or bushing 2I as is had by engagement of the tapered end 23 in the opening I0.

From theV foregoing description, it is believed that the construction, operation and advantages of the present invention will be readily understood and appreciated by those skilled in the art. Minor changes may be lmade in, details of construction, illustrated and described, such as fall within the spirit of the invention as claimed.

What I claim ist 1. A. device for resurfacing a valve seat of an engine block having spaced upper and lower portions respectively formed with cylindrical valve stem and tappet guide openings which are vertically aligned, comprising a pilot guide consisting of an elongated tubular member having an enlarged cylindrical upper end portion adapted to snugly fit in the valve stem guide opening and an externally tapered lower end adapted to simultaneously center in the tappet guide opening, said tubular member further having an axial cylindrical bore, a resurfacing head having a tubular shaft, and an expansible pilot includi-ng an elongated sleeve having the lower end portion of said shaft rotatably fitted on its upper end portion, said sleeve having an intermediate external tapered portion centered in the upper end of said bore and an expansible lower end portion snugly fitted in said bore.

2. A device for resurfacing a valve seat of an engine block having spaced upper and lower portions respectively formed with cylindrical valve stem guide and tappet guide openings which are vertically aligned, and wherein a tappet is movable in and above said tappet guide opening and has a tapered upper end, comprising a pilot guide consisting of an elongated tubular member having an enlarged cylindrical upper end portion adapted to snugly iit in the valve stem guide opening and an internally tapered lower end 'adapted to simultaneously center on the upper end of the tappet when the latter is in an elevated position, said tubular member further having an axial cylindrical bore, a resurfacing head having a tubular shaft, and an expansible pilot including an elongated sleeve having the lower end portion of said shaft rotatably fitted on its upper end portion, said sleeve having an intermediate external tapered portion centered in the upper end of said bore and an expansible lower end portion snugly tted in said bore.

HERMAN H. REETZ.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 1,636,560 Hall July 19, 1927 1,667,918 Willis May 1, 1928 1,725,126 Berg Aug. 20, 1929 l2,042,759 Albertson June 2, 1936 2,150,621 Hall Mar. 14, 1939 2,338,484 Beverlin Jan. 4, 1944 2,394,882 Weynand Feb. 12, 1946

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