US 2607331 A
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G 1 W m 3 F L E 3. M M 7 V O 0 m w mA A 2 0 SA E2 Rw A w H v. E BP C. A. WEFING COVER FOR VALVE-IN-HEAD MOTORS Flled April 22 1950 Aug. 19, 1952 Patented Aug. 19, 1952 crimes A fWefing, Diiv Application April 2211950, $3651 1536. 155, 52? 3' crime; (01. 123 96) i c iei iit r lt f t im hinri c v rs; f
dimorenerti a t9 Valve were??? 195% a ype oi eutqm bile e i amiheses an"ob;ject to provide a valve cover which silences objectionable noises such for example, 'aslthose produced by loose adjustments oi the rocker-arm assembly enclosed by the cover.
A the ob o th inve i fj i qierei ifie a valve eq r rm d sa rigid n t hi h smtl responsive to the pitch of noise produce'dby the cha i m encl sed W in t e c e mi therebir to prevent such noises from being transt edeu si e t n t.
a co e i9? en sin the, r kerrm se mb y .a lve mh dwxn r w h pv un ias a rigid unit responsive to a single tone or fre illustr qth object of t is. n e on; is to viiii le? a a e or rp h hs ma b a i y. 121@ d A11 9? 7. a i y rimhead mo r .in nr ntiqnal man e v to nc os i t ro er arm assemh i h re nkandp ic ha /su h" ri t at it willns a t ehtl w against the' motor headusing only a minimum mb r i as e insm nt 1 Yet another objectof this invent on'is to'i rof;
vide Ja}va1ve* cover 'of the character described 1 which is simple in construction; economical in;
cost; sturdyandhaving' eflicient life span equal at least to thelife'of the motor.
Withthese and-other objects in View, all of hiq nq qifvq y hemi erv a p a myinven- V e ingfq jt t c n I Figure is a bottoziiv ew'o'r one'endpor tion the cover, on the same scale" as Eigizffto show" const" lotions otherwisenot elearly illustratd ure is a' fragmentary view, onan enlarged scale, of an attaching 'means' as tak'en on'th' indicated line fi fiofFig; 1,. v "ure '7 is a rragmema'ry view,on anieril'arged seal f'afseajting con u'c'tio'n, as taken on' the indicatedfline l- -ilbf, F
sm t eva1v m v v a type tl haliw bv fe n tio iiable'ito many people 'because fof noises which occur'in the rocke'rarin assembly of 'the 'valiies ontop oi the motor, I n the drawing ithejreis Qkt drill f sl m l .11 v 933 9 e" @559 which comprises a plurality "of rocker arms [2? push rods l3, and valve stems IA, Each push rodf l tisconnected withpne end'iporti'on of a E k'ef mizyana i l i t m 4 islc n ied to the other end port on. An'i upward movement 0f the pu hrodf tatesthe roclierariri'iltoide-i pres the valve st lfl andl open' the valve. Con'-' the low ng' of thje pushrod permitsth I 151 'g bf s em l Tanii ire'stilti ie bsme. 6f valve. 1 In good motor adjustmentthere is pro}, videda certain amount oi c'lea'rance in this train i of mechanismsto assurethe complete, closure of] iieli l Ywli 'ihe 1 15 219 b d P et s v, us h. i an Iii- 12 t h mm .4 able} for Jthe, motor parts, especially thevalve .steifis',ffbecome heatdnuring motor operation n c ises. eert i n w m nqvel t s u im tions, combinations and arrangements of form andtrnateria ls as hereinafter described olee mim ppe ded d m an lu trat in pref ed embodiment in the accompanying dra ng in "whichq grwmhiatib in fiafur; l u retin enqmbQfimexit of the present invention as placed upon a conventional valve-in-head motor in condition for use.
creasesfall' 'cleara'n'celsl With ;the prop er clear ances in the aforesaid elements; considerable v noise results f romthe running crime engine, and
Figure 2 is asection, on an enlarged scale, as
takenjon thefindicated line 2--2 of lfig 1 to illusi trateithecbver enclosing a conventionalrockerassembly on the headof the motor, 7
the'aixdmrs dr their automobiles almost complete-f 1y silent, there is a tendency to adjust throcker' t itheil pressiojn I l m d n..,th 'untraiii' i l arm asseifibly' of these" valve-in-hea'd motors tightly and thusf eliminate noise "regardless of the fact that? such adjustment" is inffieient and:
causesthe 'valvesto burni out prematurely.
Figure 3" is a section as taken ontheiindioated un'eQ -s of Fig.- 2 but showing the cov'e r o nly.
Fieui'e' ifis a section on afurther scale, as taken on the'indicatedline d -d of Fig 1,
Theyjconventional valve.- cover which enclosesi theimcker armassembly simply protects; the: l tin spar s irom. dirt; and r tains oil flowing; 11 ass mb r uch; co ersaredesi nedfor: A.
" s me? ltunt ibm; ndr cenrd n l a e mater-1 a cheap 'm'anner'such as by drawing or stamping a piece of sheet metal into the proper form with suitable ribs or corrugations folded therein to enhance the structural rigidity and permit the cover to be held in place with a minimum number of fastenings. No consideration is given to the tones and sound frequencies to which the cover is responsive and the corrugate rib reinforced construction makes the cover responsive to noises of many pitches as indicated by an offtone sound of such a cover which occurs when it is struck a blow. In essence, the conventional cover acts largely as a sound box, transmitting all the motor noises to the outside and probably magnifying some noises of certain pitch.
The present invention comprises an improved cover having a tone or frequency characteristic which will not respond to frequencies of noises produced by the rocker arm assembly, effectively confining such noises within the cover and thereby silencing the motor. In attaining this improved construction several factors were determined as limitations of my construction and such factors are herein enumerated to facilitate an understanding of the invention:
(a) A cover which naturally vibrates at a frequency the same as'the noise of the machinery it encloses tends to resonate and actually makes the noise sound louder.
(b) A cover formed of thin sheet materia1 reinforced by corrugate or folded ribs to provide a plurality of fiat plate-like sections in the cover, tends to vibrate at a number of different frequencies as indicated by the cover emitting adull offtone sound when struck by a blow, and such cover will transmit, to the outside, noises'of vari- By the construction and arrangement of ele-t:
ments as hereinafter described, my valve cover is responsive to a single high frequency tone and with such cover placed over the rocker arm assembly of a valve-in-head motor, a remarkable silencing'of the motor is attained. n
In the illustrated embodiment the rocker arm effectively responds to a single tone or frequency which may be easily ascertained by striking it.
It was found that a casting of aluminum was the most desirable manner of providing a lightweight cover having sufficient rigidity to respond to a natural frequency or tone higher than the frequency or pitch of the motor noises which are to be shielded. An appreciable wall thickness of the cover was found necessary to produce the high pitch tone desired, and it was found that one skilled in the art of casting metals can determine, by a process familiar to the art, a thickness sufficient to produce a given tone or pitch. Other metals than aluminum may be used, and the cover may be formed by other methods than casting. To attain a given frequency, the facassembly ll contains certain cross bars I5 which inforce the cover and hold a cap 29 in place, closing the opening 19.
The cover H is formed as a box-like openbottom structure having the front wall 2| and rear wall 22 joining the top- 23 and side walls 24.,
All of these walls are preferably of uniform thickness with their joining edges rounded on a fairly large radius to permit the'walls and top to fairinto each other in a smooth bell-like construction whereby the appearance is sug estive of an elongated bell.- With such construction the'cover tors which must be considered include the wall thickness and also the density of the material and its inherent elasticity.
A plurality of regularly-spaced solid transverse ribs may be used optionally to reinforce the cover. Preferred construction may include upstanding ribs 25 on each side wall on the interior of the cover joined by transverse arches 26 across the top 23. Ribs and arches of solid and rigid construction and uniformly spaced, act as node points and thereby greatlyincrease the natural frequency of the cover.
In addition to the transverse ribs hereinabove described, a longitudinal rib 21 may be provided along the top 23, preferably in line with the openings therein through which the studs l6 are passed. At each opening, the rib 2'! may be diverged to form a collar 28 to reinforce said opening 29. Where the elements are suitably positicned a transverse arch 26 may likewise join the collar 28 to further reinforce the structure as indicated in Fig. 5.
The openings 29 which receive therethrough the studs 15 are larger in diameter than the studs to accommodate cylindrical flanged spacers 36 through which the studs 16 are inserted. The spacers 30 are composed of rubber or rubber-like material which is not affected by chemical action of oil or by heat, their function being to provide a resilient separation layer between the cover and the studs Hi to eliminate the possibility of transmitting any high-frequency vibrations from the studs to the cover. Suitably interposed between the flanged portion of each spacer 3i] and the nuts [8 on the stud I6 is a washer 3! designed to lock the nut in position and seal the opening 29 by the spacer 30.
The base of the cover is suitably formed as a flattened shelf 32 by extended feet 33 along the walls to provide the necessary increased thickness at the shelf. The feet 33 of each side maybe selectively turned inwardly or outwardly as de sirable to provide proper clearances for enclosed motor parts. A strip gasket 34 may seal the cover at its base, and it is preferable that the gasket 34 be of resilient or rubber-like material, or corklike material to eliminate any tendency for high frequency vibrations within the motor block to be transmitted into the cover.
It will be seen that the structure hereinbefore describedaccomplishes the two functions of a rigid, tight-fitting efficient cover'and a shield or confiner of the noises created by the operation of the valvehead assembly. The cast aluminum cover, which is the preferred embodiment of the present invention, has the further very useful function, namely, that it absorbs a large quantity of the motor generated heat and retains it, the
advantages thereof being obvious to motor users and those skilled in the art.
While I have described and illustrated my invention in detail, other alternatives and equivalents will occur to those skilled in the art which are within the scope of my invention, and I therefore desire that my protection be limited, not by the details of the above-described arrangements and structure, but only by the true spirit and scope of the appended claims.
1. A method of manufacturing a cover for a rocker arm assembly of a valve-in-head motor, including walls and a top being of substantial uniform thickness and having all joining edges curved in a substantial connective radius to integrate said walls with each other and with said top, comprising ascertaining the tone of the noises produced by operation of the rocker arm assembly, casting the cover of metal with the wall and top thickness so correlated with the dimensions of the wall and the top as to provide a structure having a natural tone higher than the tone produced by the operation of the rocker arm assembly.
2. The method of manufacturing a metallic cover unit of walls and top for the rocker arm assembly of a valve-in-head motor, including ascertaining the vibratory frequency of the noises produced by the operation of the rocker arm assembly, casting the unit of metal with thickness of the walls and the top substantially uniform having their junctions curved on a substantial radius to connectively integrate the walls and top into a unit adapted to respond to a single frequency vibration and correlating the dimensions of the walls and top with each other and with the metal density and elasticity to establish such single frequency at a point higher than the vibration frequency of the noises produced by the operation of the enclosed rocker arm assembly.
3. In the method described in claim 2, an additional step in the casting of the cover, namely, providing regularly and selectively spaced transverse ribs of the same material and integral with the body of the casting, said spacing being such as to form node points to cause said cover to vibrate at frequencies established by the spacing of said node points.
CHARLES A. WEFING.
REFERENCES CITED The following references are of record in the file of this patent:
UNITED STATES PATENTS Number Name Date 1,268,047 Norman May 28, 1918 2,224,376 Chayne et al Dec. 10, 1940 FOREIGN PATENTS Number Country Date 668,308 France Oct. 30, 1929 499,667 Great Britain Jan.. 27, 1939