US2019252A - Valve operating means - Google Patents

Description

Oct. 29, 1935. E. B. coTTlNGHAM VALVE OPE'RATING MEANS Mara/ @iQ/2 Filed NOV. 25, 1932 Patented Oct. 29, 1935 UNITED STATES PATENT GFFICE VALVE OPERATING MEANS Application November 25, 1932, Serial No. 644,299

2 Claims.

My invention relates to valve operating means, particularly to valve operating means for the poppet valves of internal combustion engines, and its object is to provide a liquid operated device for 5 opening the valves without the usual metallic click and without push rod adjustments and valve clearances.

I am aware that devices operated through the medium of confined liquid pressure have been proposed before, but such devices have been of complicated character requiring numerous parts and material changes in the usual valve equipment. 'I'hese devices have not been adapted for reducing the speed of the motor in the event of l5 oil pressure failure and they have required great precision in the parts. They have not made compensation for cam wear and they have been subject to disability by the trapping of air.

The device of my present invention is composed of few parts of simple character and is adapted to be installed without material change in the usual valve equipment. The push rod or tappet is made up of two parts between which the liquid pressure is confined and means is provided for closing communication with the liquid line upon the initial rise of the lower part an-d independent of cam wear and the amount of drop of the lower tappet part. Communication with the liquid line is not controlled positionally by the tappet parts,

nor by means of a port in one of said parts, and therefore precision in the parts is not necessary. The tappet parts are preferably proportioned so that, in the event of liquid pressure failure, the valve will not be lifted sufficiently to run the engine at driving speed, but will be opened an amount which will allow the engine t-o operate very slowly.

The present invention further provides for locking the liquid line against communication with the space between the valve tappet parts, and

when this line is locked against such communication the valves may not be lifted suciently to run the engine at all, or they may be lifted an amount insuicient to run the engine at driving speed but sufficient t-o allow the engine to operate very slowly.

The invention further provides a modification for operating a high-lift valve with a low-lift cam. Heretofore, a high-lift valve has required a highlift cam and the usual high-lift cam had to be made thinner toward the high-lift point to maintain the desired speed of opening and correct valve timing. This thinner formation of the cam toward the high-lift point has caused the valves to open with a knock rather than with a smooth cam action, whereas the high-lift valve embodiment of the present invention provides the high valve lift with a low lift cam and with a smooth cam action and correct valve timing.

In order t-o acquaint those skilled in the art 5 with the manner of constructing and operating the present invention, I shall now describe, in connection with the accompanying drawing, certain specific embodiments which are illustrative and not limiting of the present invention. 10

In the drawing:

Figure 1 is a fragmentary vertical section of an internal combustion engine equipped with a valve operating device embodying the present invention; l5

Figure 2 is a fragmentary detail section taken on the line 2 2- of Figure 1; y

Figure 3 is a fragmentary vertical section showing an over-head type valve embodying the present invention; and 20 Figure 4 is a fragmentary vertical section showing a modification for operating a high-lift valve with a low-lift cam.

Referring to the drawing, the crank-case 5 may be the usual or any suitable or preferred crank- 25 case, the top of which forms an engine base 6. One of the cylinders is shown fragmentarily at 1, this cylinder 'I being water-jacketed at 8 and provided with the usual bore 9 in which the piston I0 operates. 30

The port II may be an inlet port or an exhaust port and it opens from the manifold I2 into the combustion chamber I3 and has a valve seat I4. The cylinder head I 5 is water-jacketed at I6 and gasketed at I'Ito the cylinder block I. 35

The valve head I8 is movable into and out of engagement with the seat I4 and has a depending valve stem I9 operating in a valve guide bushing 20. The valve head I8 is yieldingly urged toward and onto the valve seat I4 by a spring 2I 40 encircling the stem I9 and interposed between a shoulder on the bushing 20 and a spring support 22. The support 22 rests on a transverse pin 23 in the valve stem I9.

A cam lifter for the valve I8 is shown at 25, 45 this cam lifter 25 being spaced below the lower end of the stem I9 for interposition of the usual push rod or tappet between it and the valve stem.

The valve tappet means is provided with a valve tappet guide, indicated more or less diagram- 50 matically at 26, as depending from the engine base 6 into the crank-case 5. This guide may be provided with a bushing (not shown) which may be renewed when worn.

The lifter cam 25 is disposed within the crank- 55 case 5 and the engine is provided with the usual forced feed or pressure lubricating system which includes a tube 28 connected with a suitable pump (not shown) and extending through the crank-case 5 for distributing the oil under pressure to the main crank-shaft, connecting-rod and other bearings.

The elements above described are illustrative of the elements now in common use, and it is to be understood that these parts may vary widely under existing practice and knowledge in this art. For example, the tappet guide may be disposed above the engine base and outside the crank-case, and, as will hereinafter appear, the Valve may be of the over-head type.

I shall now proceed to describe in detail the new elements which alone and in combination with the old elements, or their equivalents, constitute the present invention.

The valve tappet, instead of comprising the usual tappet integral from end to end, is made up in two parts, the upper part being indicated at 30 and the lower tappet part at 3|. Each part 30 and 3| has direct sliding fit in the guide 26 and the combined lengths of these parts is preferably sufficiently less than the distance between the Valve lifter 25 and the lower end of the stem I9 that, upon loss of the liquid from the 'space between the tappet parts, the valve I8 will not be lifted sufficiently to run the motor at driving speed but will be lifted an amount which will allow the motor to operate very slowly. Upon loss of liquid from the space between the tappet parts, which space is indicated at 34, the upper part 3B will drop down into engagement with the lower part 3| and, in one suitable embodiment of the invention, the mechanical lift imparted to the valve I8 without the oil cushion between the tappet parts may be from onesixteenth to three-sixteenths of an inch to start the motor, the balance of the nine-sixteenths inch lift, or whatever lift may be desired, being obtained only when the oil cushion is operative between the tappet parts.

The upper tappet part 30 need only consist of a shaft of steelas the usual adjustment and clearance provisions between the upper end of this part and the lower end of the Valve stem I9 may be omitted entirely. 'I'he lower part 3I may also be of solid form and its upper end has a reduced projection 36 forming an annular space between thetappet parts when the lower end of the upper part is seated on the upper end of the lower part.

The push rod or tappet guide 26 has an inlet 38 in such position. that, when the cam 25 is in valveclosed position, the inlet 38 is just above the large portion of the bottom tappet part 3|. A light coiled spring 39 may be interposed between the upper and lower tappet parts to insure the return of the lower part to its lowest position. The lower part 3| has the customary mushroom 40 or rollers for engagement with the cam lifter 25.

The oil inlet 38 is connected to an oil line 4|, which line 4I is in turn connected to the regular oil feed or pressure line of the motor, as, for example, to the distributing tube 28 as shown, although, of course, the particular point of connection may vary. The oil inlet 42 between the line 4| and the inlet port 38 is provided with a check valve 45 which opens toward the inlet port 38 and closes in the opposite direction. The check valve shown is in the form of a ball check confined in a cage 46 formed by prongs extending from an axially bored nipple 41 threaded into the lateral boss 48 on the tappet guide 26.

The operation of the device, as thus far described, is as follows:

With the motor running, the space 34 between 5 the upper and lower tappet parts 30 and 3| is filled with oil under the normal pressure, the check valve 45 being opened to allow the space 34 to remain full of oil. The confined liquid pressure between the tappet parts holds the upper 10 part 30 in engagement with the lower end of the stem I9 and the lower or mushroom means 46 on the lower part 3| in engagement with the lifter cam 25. As soon as the cam 25 starts to lift the push rod the check valve 45 closes communica- 15 tion between the space 34 and the liquid line, and the pressure of the cam on the lower tappet 3| causes the confined oil cushion between the tappet parts to lift the upper tappet part and, through it, the valve I8 from its seat I4 in the 20 usual manner. A small portion of the oil may escape along the bore of the guide 26 to assure good valve lubrication.

In the event of wear between the valve I8 and the seat I4 the valve will be lowered in operation, 25 but this is automatically compensated for by the Iilling of the space 34 with oil from the line 4|. Expansionof the valve and valve stem due to heat is automatically compensated for in the same manner, and wear between the cam lifter 25 and 30 the lower tappet part 3| is similarly compensated for.

In the event the cam 25 becomes worn, the lower tappet part 3| will operate to lower positions, but regardless of the drop of this part the check 35 valve means at 45 closes communication between the oil cushion space 34 and the oil line with the initial rise of the lower tappetpart. In other words, communication with the oil line is closed by the initial upward movement of the lower tappet part 40 and is not controlled by the position of a port in that part or any other part. A ported or positional control, such as that above referred to, would require great precision in the machining and assembly of the parts, all of which the present 4'5 invention avoids.

As already pointed out, should the oil pressure fail for any reason, as by rupture or leakage in the line, the upper tappet part 30 will drop until its lower end seats upon the top of the lower part 3| 50 and, in this position, the combined lengths of the parts 3|] and 3| preferably will be such that the valve I8 will not be lifted sufficiently to run the motor at driving speed, but will be lifted an amount which will allo-w the motor to operate very 55 slowly. The lift imparted to the valve I8 upon the loss of oil from the space 34 may, as already pointed out, be of the order of about one-quarter of the lift imparted when the oil cushion is operative between the tappet parts. Of course this may 60 vary and I contemplate making the combined lengths of the tappet parts such that the valve I8 will not be lifted appreciably or at all upon failure of the oil cushion between the tappet parts.

Although I have described the device as cone5 nected to the pressure feed oiling system of the engine, it is to be understood that certain aspects of the invention may be carried out with other liquids than oil and with the liquid supply derived from other sources than a pressure feed lubricating system for the engine.

For the purpose of locking the engine against operation at driving speed, the inlet passage 42 may be provided Awith a butteriiy valve 50, the stem 5I of which is provided with an externally 75 accessible ringer piece 52 by means of which the valve 5G may be turned into position diametrically across the passage 42 to close o communication from the line 4I. A lock 53 operated by a key 55 has locking bolt means 55 for engaging the stem 5l to lock the valve 59 in closed position. By inserting the key and retracting the locking bolt means 55 the valve 5B may be turned through 90 degrees te open communication between the line di and the inlet 38.

By locking the valve 55 in closed position the engine may be locked so that it cannot be operated at driving speeds, or if the combined lengths oi the tappet parts 3G and 3| is insuflicient to open the valve I8 appreciably or at all the engine may be locked against operation entirely. If the combined lengths of the tappet parts 30 and 3l is sujcient to lift the valve I8 only slightly, the engine may be locked to operate only very slowly and not at driving speeds. 'Ihis locking feature has utility in preventing theft or surreptitious use of automobiles, aeroplanes and the like, or it may be used to prevent unauthorized or surreptitious use of the engine for any purpose.

The valve 50 may be of a form other than a butterfly valve and its positioningin the hub 45 and close to the valve tappet parts prevents breaking the liquid line between the lock and the motor and placing pressure on the tappet or push rod in some other manner. This is further prevented by the disposition of the oil line 4l and all piping within the crank-case 5 where these parts are not accessible to unauthorized tampering,

In the embodiment of Figure 3, the invention is shown in connection with an over-head type valve. The tappet parts 3G' and 3| are disposed between the lifter cam 25 and the lower end of the valve rod 5G, and are separated and' held against the rod 55 and the cam 25', respectively, by the oil cushion in the space 34'.

The upper end of the rod is connected by a ball joint or other suitable connection at with one end of the rocker arm 63. The arm 63 is pivoted at 54, and its opposite end engages the upper end of the stem 62 extending upwardly from the valve member 6l. The valve spring 66 is positioned about the stern 62 in the usual manner, and yieldingly urges the valve member 6| toward and to its seat and the rod 55 to lowered position. As in the preceding embodiment, valve clearance is eliminated between the upper tappet part 393 and the rod @D and also between the stem S2 and the rocker arm 53. The valve operates without the usual metallic click and the oil cushion between the tappet parts compensates automatically for cam wear as well as for other wear between the parts. The necessity for valve operating adjustments is eliminated.

In the modication of Figure 4, the lower part 3i" oi the push rod or tappet is of considerably larger diameter than the upper tappet part 35". The bore 'iB in which the lower tappet part 3l" operates is of sufficient height to permit full Valve opening movement of the part 3i" without engagement of the upper end of this part with the shoulder il between the bore 'EQ and the reduced bore l2 in which operates the upper tappet part 38". The lower end of the upper part 3B" is tapered or reduced at 'i3 so that, in the event the oil or other liquid escapes and the lower end of the part 33 drops into engagement with the part 3 l when liquid pressure is again created between the tappet parts, it will operate to lift the upper and position the liquid cushion between the parts. As in the embodiment of Figure 1, the liquid line to the space 34 between the tappet parts is preferably provided with a check valve or other means for closing communication between the space 34 and the liquid line with the initial operative movement of the lower part 3 l 5 In the embodiment of Figure 4, as soon as the cam 25 starts to lift the push rod or tappet part 3 i communication with the liquid line is closed and the liquid cushion in the space 3'3" is displaced from the larg-er bore l0 into the smaller 10 bore 'i2 and lifts the part 3G to open the valve. The displacement of the liquid from the larger bore into the smaller bore produces in the part 351 greater vertical movement than is imparted to the part 3l, the vertical movement of the 15 part 30 with respect to the part 3| being in inverse proportion to the diameters of the bores E2 and '10. In this manner, with the usual lowlift cam 25" it is possible to obtain high-lift action in the part 30" and a corresponding high- 20 lift or relatively great opening movement of the connected valve member. The high-life action is not only obtained with a low-lift cam but smooth action and correct valve timing is obtained without slow initial movement and quick- 25 opening, knocking action at the end of the valve opening movement, as has been the case with the usual high-lift cams which, as already pointed out, have had to be made thinner to maintain the desired speed of opening. These thinner high- 30 lift cams have resulted in a knock at the end of the valve opening movement rather than a smooth cam action throughout the entire movement.

In each embodiment, the valve spring tension is more than ample to overcome the pressure 35 exerted by the normal oil pressure of the motor and the light coil spring. A11 spaces or clearances are eliminated and a perfectly seated valve is assured' at all times.

The two-part tappet construction, with each 0 part of solid form without ports or the like, is preferable because of its simplicity and the few parts required, but I contemplate installing a sleeve or cup on the top of the push rod or tappet and allowing the valve stem to rest in it and 45 apply the pressure in the same manner.

The embodiment of Figure 1 requires little more than cutting the usual tappet in two, foreshortening one part the desired amount and making the desired oil or other liquid connection 50 with the space between the parts.

A bleeder port may be provided as indicated at 'i5 in Figure 1, at 'l5' in Figure 3 and at 15 in Figure 4, for relieving the coniined liquid pressure between the tappet parts when the liquid 55 supply line is locked out of communication with the space between the tappet parts. If desired, the oil escape along the tappet parts may be sufiicient to relieve any confined liquid pressure without the ports 15, 15 or 15". l

The locking feature is preferably employed in connection with the inlet valves only, and the oil inlets to the inlet tappets may be interconnected between the check valves 45 and the valves 50 as shown at 'i8 in Figure 1. 05

I claim:

1. In combination, a motor provided with a valve having a depending valve operating stem, a valve lifter -disposed below the lower end of said stem, a valve tappet comprising a pair of tappet parts spaced endwise between the valve operating stem and said valve lifter, means for conning liquid under pressure in the space between the tappet parts, said liquid normally holding one` tappet part in engagement with the valve operating stem and the other tappet part in engagement with the valve lifter, the combined lengths of said tappet parts being sufficiently less than the space between the valve lifter and the operating stem so as not to lift the valve sufliciently to run the motor at driving speed upon loss of the liquid from the space between the tappet parts and suiiiciently great to open the valve an amount which will allow the motor to operate slowly.

2. In combination, a motor having a pressure lubricating system and a valve, a valve tappet guide, a lateral boss on said guide, a Valve tappet comprising a pair of tappet parts disposed in endwise spaced relation and each having sliding t in said guide, an oil pressure line for the motor,

said oil pressure line opening through said lateral boss into the guide between the tappet parts, an axially bored nipple threaded into the lateral boss on the tappet guide, a check Valve disposed in said lateral boss and seating upon said nipple for closing 01T the delivery of oil to the tappet guide in a direction away from said guide, a crank case, valve means separate from said check valve and rotatably carried by said crank case and extending into said lateral boss for closing said boss against passage of oil therethrough, and an externally accessible lock secured in said'crank case for locking said last valve means.

EDWARD B. COTTINGHAM.

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