US2175467A - Hydraulic tappet - Google Patents

Description

Oct. 10, 1939. c. E. JOHNSON HYDRAULIC TAPPE'I Filed Dec. 21, 1938 Patented Oct. 10, I939 UNI-TED STATES PATENT oFl-"icr.

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This invention relates to hydraulic tappets and is particularly concerned with the construction of a tappet which is held in an inverted or substantially inverted position and used in connec r'tion with those cylinders of engines of certain types which are inverted irom the normal upright vertical position which most engines occupy. in some cases, as for example in radial engines used in airplanes and in other places, a 10 cylinder may be vertical or perhaps-inclined to the vertical with the combustion chamber at the iowerend oi the cylinder and the crank case above it, and it is with engines 01 such type that the tappet construction the. present invention is ll concerned.

Such air as is carried by the oil from the engine to and within the bodies of hydraulic tappet's, should be separated irom the all prior to the entrance of the oil into the pressure or hy- 20 draulic chamber of the tappet, and the present invention is concerned with a simple construc- .fl nary vertical or substantially vertical cylinder engines.

. An understanding of the invention may be had from the following description, taken in connection with the accompanying drawing, in 80 which:

Fig. 1 isa vertical section through an inverted cylinder structure to which my invention is applicable.

Fig. 2 is a similar vertical section through the so tappet. and

Pig. 3 is a horizontal section on the plane of line 3-8 of Fig. 2, loking upwardly in the direction indicated.

Like reference characters refer to like parts 40 in the diflerent figures of the drawing.

The engine block includes the engine cylinder l, inwhich a piston 2 is reciprocable, having ports as at I for the entrance of the fuel mixture and for the escape of the exhaust gases. 45 At the lower end of each port leading into the combustion chamber of the engine cylinder is a valve 4 having an upwardly extending stem 9, acted upon by a coiled pressure spring 8 to normally hold the valve in closed position. The

so cam shaft 1 with the cams. I thereon for opening the valves on rotation 01 the shaft is located above the tappet, the body of which is indicated at 9, and which is interposed between a cam and the upper endoi the valve stem 5.

5s The tappet body 9 is guided vertically in a vertical opening made in a guide sleeve portion iii of the engine block. The body has a continuous annular groove Ii around its outer side between its upper and lower ends, to which oil under pressure is carried by branch conduits l2 6 from a main oil conduit ll into which the oil is pumped by the engine pump, there being a branch l2 from the main conduit for each of the tappets; The body 9 is closed at its upper end as indicated at I4, cam 8 bearing there- 10 against. The body is hollow and in the lower end a hollow piston structure I5 is mounted, the lower end being closed by a hardened wear plate It against which the upper end of the valve stem bears. The piston I! has an outstanding annular flange II, the diameter of which is slightly less than the interlpr diameter of the body 9. There is a split ring it above the flange II for guarding against any excess passage of oil in the same manner as in my Patent No. 2,090,795, issued August 24, 1937.

Within the tappet body and between its upper and lower ends is a valve cage member and partition is having an outwardly extending flange 20 which has a press-fit within the body as shown, the upper end oi the member I! having an opening for oil passage closed at its lower side by a flat plate valve-2i which is held normally in an upper closed position, a light spring 22 resting at its lower end on a combined base 80 plate spring cage member 23. A relatively heavy coiled compression spring 24 is located between the split ring it and the plate 23, as shown. This structure is substantially the same as that shown in my patent above identified and in my pend- 86 ing application Serial No. 122,234, flied January 25, 1937, now Patent No. 2,145,484, issued January 31, 1939.

The upper space within the tappet body 9 pro-\ vides an oil receiving chamber 25 into which the oil passes from the groove ii. In one side of the tappet body an inset elongated boss 26 is cast extending upwardly and inwardly and which, lengthwise thereof, has an upwardly and inwardly extending passage 21 providing a communicating conduit between thegroove II and oil chamber 25. It, is evident that the oil must be passed upwardly through the passage 21 and be delivered to the chamber 25 near its upper end. A small opening or passage 28 is drilled or otherwise made through the wall of the body 9 at its upper end, such passage leading from the chamber 25 to the outside end serving to carry of! any air which naturallywill separate and rise vertically from the body 0! oil within 56 2 I amass? the'chamber- II above the upper level thereof and be carried outwardly through the passage at 28.

With this invention the oil supply in a relatively considerablebody is maintained constant in the chamber 2! and is held therein an appreciable and amply sumcient time for air delivered thereto with the oil at the upper part of the chamber to separate from the oil and pass outwardly through the passage at 28, whereby any oil that passes the valve II will be substantially if not entirely free of air.

The construction described, while of a simple nature, is practical, easily manufactured and efficiently serves the purpose for which it is designed. The invention is defined in the appended claims and is to be considered comprehensive of all forms of structure coming within their scope.

I claim:

1. A hollow valve tappet body closed at its upper end, a partition having a passage therethrough within and between the ends 0! the tappet body providing an oil receiving chamber above the partition and in the upper end of said body, a spring actuated valve closing said opening in the partition, said tappet body having an annular groove around its outer side between its ends and an upwardly extending passage leading from said groove into said chamber and communicating therewith, the upper end of said passage being located near the closed upper end of the body; and a wall of said tappet body near the upper end thereof having a passage therethrough of small cross sectional area for the escape of air.

2. A tappet construction comprising, a hollow tappet body closed at its upper end, a valved partition within and across the body between its ends, thereby providing an oil receiving chamber above the partition and in the upper end of the body, said tappet body having an annular groove around and between its ends and provided with an inset vertically extending boss at the inner side of the vertical wall of said body, the end 0! said boss terminating a short distance below the closed upper end of the body and said boss having a longitudinal upwardly extending passage from said groove to the upper end 01 the boss, and a wall of said tappet having a limited air passing opening therethrough communicating with said oil chamber closely adjacent its upper end.

CHARLES E. JOHNSON.

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