US1924847A - Internal combustion engine - Google Patents

Description

9, 1933. H. c. EDWARDS INTERNAL COMBUSTION ENGINE Filed Dec. '4, 1931 gwmmtoo HERBERT 5'. 501415505.

dttoamq Patented Aug. 29, 1933 1,924,847

UNITED STATES PATENT OFFICE,

INTERNAL COMBUSTION ENGINE Herbert 0. Edwards, Detroit, Mich, assignor to Packard Motor Car Company, Detroit, Mich., a corporation of Michigan Application December 4, 1931. Serial No. 579,002

11 Claims. (Cl. 251-144) This invention relates to internal combustion poppet valve 12 in the usual manner and as engines and more particularly to the valve mechshown, the valve and valve gear are housed in a anism thereof. compartment 13 which forms a part of a cylinder An object of the invention is to provide a new head 14 and may be provided with a removable and novel manner of interconnecting engine cover 15 permitting access to the compartment. 0

valve stems with their spring collars. The poppet valve is provided with a stem 16,

Another object of the invention is to provide preferably integral therewith, which is slidably means for interconnecting the valve stems of inmounted in a bearing sleeve 17 mounted in the ternal combustion engines with the valve closing cylinder head. A flanged collar 18 is associated means thereof in a manner obviating wear and with upper end of the valve stem 16 and extend- 5 consequent loosening of the associated parts. ing between this collar and a partition 19 of the A further object of the invention is to provide cylinder head is a compression spring 21, mounta valve stem of an internal'combustion engine ed in the well known manner to exert a force with a key member for securing a valve spring upon the valve stem 16 urging the valve head retaining and supporting collar thereto, the key against its seat 9. The valve is opened and member and the stem being so constructed and closed by suitable tappet mechanism and actuatrelated as to provide a relatively large area of ing mechanism therefor (not shown), in amansurface contact therebetween. ner familiar to those skilled in the art to which Still another object of the invention is the this invention pertains. It will be readily under- 20 provision of a split tapered key member, for sestood that downward or opening movement of the curing a valve stem of an internal combustion valve 12 is obtained by the action of the tappet engine to the valve spring retaining and supmechanism on the end of the valve stem 16 and porting collar thereof, which is threaded on the that upward or closing movement of the valve is valve stem and is provided with means coacting secured by the expansive action of the spring 21.

25 with means formed on the valve stem to lock the It has been common practice to turn an ankey against rotation relative to the valve stem. nular groove in the valve stem 16 near the end Another object of the invention resides in the thereof thus forming asmall flange portion. A provision of a structure of the character specisplit tapered key member is seated in the annular fied which is economical to manufacture, light groove and has a small surface on one end thereof 30 in weight, simple in design and easy to assemble. which bears against the flanged portion, of the Other objects and advantages'of the invention valve stem, and a valve spring retaining and supwill appear from the following description taken porting collar having a complementary tapered in connection with the accompanying single sheet bore is seated onthe split key in wedging relaof drawing which forms a part of this specification thereto. In such structures, however, the

35 tion and in which: small flange of the valve stem "is forced to carry Fig. l is avertical sectional view through a the entire thrust load of the compression spring portion of an internal combustion engine show- 21, with the result that the continued opening ing a poppet valve thereof in elevation and the and closing of the valve leads to excessive wear application of the present invention thereto. on the flange portion and on the key members.

40 Fig. 2 is a view taken substantially on the line Furthermore, in constructions of this character, 22' of Fig. 1 and looking in the direction indino means are provided for preventing relative cated. rotation of the keys and the valve stems. The

7 Fig.3 is an elevational view showing one seccombined result of this construction has been tion of the split key member forming a part of that both the keys and the valve stem would be- 45 this invention. come loose and worn, causing jumping ofthe Fig. 4 is an enlarged sectional view showing the valve, noise and many other undesirable features. formation and relation of the threads of the key It has also been proposed to machine the valve member and the valve stem. stem to form laterally extending grooves and ribs Fig. 5 is a fragmentary elevational view of the or corrugations near the end thereof. A tapered, 50 upper portion of the valve stem; split key member'having mating or complemen- Referring to the drawing, at 10 is shown a tary grooves or corrugations has been secured to portion of the cylinder block, of a radial type the ribbed end of the valve stem by a valve spring internal combustion engine, having the usual pasretaining and supporting collar having a tapered sageway ll'which maybe for either the intake bore therein. This construction, while being an or exhaust. The passageway is controlled by a improvement over the construction previously de- 0 scribed, is deficient because of the difficulty in properly machining the corrugations or ribs. It has been found that it is practically impossible to uniformly machine the corrugations on both the valve. stem and the key member, with the result that in most cases the entire thrust load of the compression spring is carried by one or possibly two corrugations. This situation results in the corrugation, which does carry the load, becoming chipped and worn at its edges or sides so that a loose fit results with the consequent disadvantages. In some cases the parts have become so worn due to these conditions that the keys have dropped out into the engine mechanism causing serious damage.

Another conventional method employed in this connection is to form the valve stem with'screw threads thereon and to provide a split key member having mating screw threads. The key member is screwed on the valve stem and is also held in place by a spring collar having a tapered bore. Structures of this character have been reasonably satisfactory, but serious difiiculty has been experienced in this type of device because the key member tends to back ofif the valve stem or unscrew itself therefrom due to the tendency of the spring collar to rotate. When the key memberpartially unscrews itself, it will be apparent that the tension of the closing spring is changed, thereby affecting the precision setting which must be maintained for eflicient operation of the valve. Keys formed in this manner frequently become unscrewed to a point where .they drop off the valve stem and allow the collar and spring to do likewise.

In the present invention the disadvantages, above pointed out, are obviated by a structure in which the key member is secured to the valve stem by screw threads; and the split key member is non-rotatably mounted on the valve stem so that relative movement of these parts is impossible. The invention also provides screw threads formed in a particular manner whereby a relatively large surface contacting area between the parts is secured.

As shown, the upper end of the valve stem is provided with a screw thread 22 which consists of several convolutions having a uniform pitch. The key member as shown comprises two segmental portions, 23 and 24 havingscrew threads 25 formed therein which mate with thescrew threads formed on the valve stem. These matmg spiral screw threads on both members, be cause of their uniform pitch, tend to providea relatively large surface contacting area between the key member and the valve stem.

To further obtain a greater surface engagement between the sections of the key member and the valve stem, the threads thereof are formed in amanner to secure a maximum surface contact therebetween. As shown, the threads 22 of the valve stem 16 are formed so that the root portions 26 thereof have a-radius or curved portion and the crest portions 27 are fiat. The complementary threads on the portions 23 and 24 of the key member are formed with a radius or curved portion'at their crests 28 and the root portions 29 thereof are substantially curved, as shown, to provide the'necessary clearance between the threads.

To further obviate wear of the parts and to prevent the: key member from backing off the valve stem, it is desirable that thesememb'ers be locked against relative rotation. To this end, portions of the end of the valve stem 16 on two face portions 31 ofthe valve stem, so that rotation of the key member relativeto' the" valve stem is prevented.

The key member is tapered, as shown, in the usual manner and the spring collar 18 has a complementary tapered bore 34 adapted to encircle the sections of the key member and to secure them on the end of the valve stem with a wedging action. It will be understood that in assembling the device, the spring 21 is first positioned about the valve stem. The collar 18 is then placed in position within the end of the spring and the spring is compressed. The two sections of the key member are then positioned on the end of the valve stem with the threaded portions in mating relation and the flat faces of the key members engaging the flat faces of the valve stem, at which time the collar, under the pressure of the spring, is allowed to slip upwardly over the key members thus securing them tightly in position with a wedging action under spring tension.

In manufacturing the parts of this assembly the valve stem threads may be formed on a screw threading machine in the well known manner and the valve stem may then be machined to form the flat face portions 31 on the upper end thereof. The tapered key member may be formed in one piece and then diametrically slotted to form the shoulder portions 32 and the fiat faces or shoulder portions 33. The key member may then be machined with the proper tap to form the threads interiorly thereof after which it may be split or cut in half forming two complementary sections each of which is adapted tomate with the threaded portion of the valve stem and the shoulder portions thereof will lie against the flat portions of the valvestem. The parts may thenbe hardened in any suitable well known manner.

It will be seen from the above description that a device has been provided which is very simple in construction and economical to manufacture. By the provision of spiral screw threads having rounded roots or bottoms, a, uniform bearing surface is obtained, betweenthe parts the area of which is relatively large. The screw threads may be easily and quickly formed on the parts by a screw thread machine of conventional design so that a uniform pitch to the threads is assured.

While only one specific embodiment has been shown and described, itwill be' apparent to those skilled in the art that the invention is susceptible of numerous changes in construction and design without departing from the spirit or scope thereof and it is therefore to be limited only by the appended claims.-

Having thus described the invention, what is claimed and desired to be secured by Letters Patentisi H 1. In an internal combustion engine, a circular valve stem having a portion thereof formed with a flat face and with a threaded portion, a collar encircling the valve stem and having a tapered axial bore, and a split key between the collar and the valve stem, the outer surface of said key being tapered to wedgingly engage the tapered surface of the collar, and a portion of the inner surface of the key being formed with a fiat face engageable with the flat face formed on the valve stem to prevent relative rotation thereof and a portion of the inner surface of the key being threaded to engage with the threaded portion of the valve stem.

2. In an internal combustion engine, a valve stem having screw threads and flat faces formed thereon, a spring supporting collar encircling the valve stem and having a tapered axial bore, a tapered split key wedgingly engaging the tapered surface of the collar and being formed with screw threads engaging the threads on the valve stem in mating relation, the inner peripheral surface of the key being formed with flat faces engaging the flat faces of the valve stem to relatively fix the valve stem and the key.

3. In an internal combustion engine, a circular valve stem having flat faces formed on the periphery thereof and a threaded portion, tapered key means having fiat faces engaging the flat faces on the valve stem and a threaded portion engaging the threaded portion of the valve stem, and a valve spring retaining collar engaging the key means.

4. In an internal combustion engine, a circular valve stem having screw threads and a fiat face formed thereon, and key means having mating threads engaging the threads on the valve stem, said key means being formed with a flat face engaging the flat face on the valve stem to prevent relative rotation thereof. V

5. In an internal combustion engine, a circular valve stem having screw threads formed thereon and having a flat face formed on the periphery thereof, key means having mating threads engaging the threads on the valve stem and being formed with a fiat face engaging the flat face on the valve stem, and a spring retaining collar supported on the key means.

6. In an internal combustion engine, a circular valve stem having screw threads formed thereon and having flat faces formed on the peripheral surface thereof, and key means associated with the valve stem comprising a plurality of tapered segmental sections formed with mating threads engaging the threads on the valve stem, said sections having flat faces formed thereon engaging the flat faces on the valve stem.

'7. In an internal combustion engine, a circular valve stem having screw threads formed thereon and having flat faces formed on the peripheral surface thereof, key means associated with the valve stem comprising a plurality of tapered segmental sections formed with mating threads engaging the threads on the valve stem, said segmental sections having flat faces formed thereon engaging the fiat faces on the valve stem, and a valve spring retaining collar engaging the segmental sections, the inner surface of said collar being tapered in a manner'to co-act with the segmental sections to secure them in position and to secure the collar thereto.

8. In a valve gear for an internal combustion engine, a valve stem having flat faces formed thereon and a threaded portion, tapered key means having fiat facesengaging the fiat faces on the valve stem and having a threaded portion engaging the threaded portion of the valve stem, and a valve spring retaining collar supported on the key means. V

9. In a valve ear for an internal combustion engine, a valve stem having threads formed thereon and having flat faces formed on the periphery. thereof, tapered key means entirely supported by the threads on the valve stem and having flat faces engaging the fiat faces on the valve stem, and a valve spring retaining collar supported by the key means.

10. In a valve gear for an internal combustion engine, a valve stem having screw threads formed thereon, said threads having a curved portion at their roots and being formed flat at their crests, key means on the valve stem having screw threadsengaging the threads on the valve stem in mating relation, the threads on the key means having a curved portion at their crests and being substantially rounded at their roots, and a valve spring supporting collar on the key.

11. In a valve gear for an internal combustion engine, a valve stem'having a screw thread formed thereon, key means on the valve stem formed with a screw thread engaging the thread on the valve stem in mating relation, one of the threads having a curved portion at its root and being formed flat at its crest, and the other of said 12 HERBERT c. EDWARDS. 1

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