US1546690A - Timer for internal-combustion engines - Google Patents

Description

July 21, 1925.

BrvOLKMAR TIMER FOR INTERNAL COMBUSTION ENGINES Filed Dec. 9, 1920 Inventor:

Patented July 21, 1925.

PATENT OFFICE.

BERNHARD VOLKMAR, OF NEW YORK, N. Y.

TIMER- i on INTERNAL-COMBUSTION ENGINES.

, Application filed December 9, 1920. Serial No. 429,315.

To all whom it may concern:

Be it known that I, BERNHARD VOLKMAR, a citizen of the United States, residing at the borough of Bronx, in the city of New York, county of Bronx, and State of New York, have invented certain new and useful Improvements in Timers for Internal-Combustion Engines, of which the following is a specification, reference being bad therein to the accompanying drawings, which form a partthereof.

y invention relates to timers for internal combustion engines, and more particularly to a mechanism of this character having a particular form of contact brush adapted to be assembled and-used in connection with a shiftable commutator ring now commonly used in connection with the engines in a certain well known and popular lowpriced automobile.

In timing mechanisms of the character to which my invention relates, it has been the general practice to employ a roller mounted upon a spring-pressed oscillatory bell crank lever, said roller being mounted upon a fixed pivot in said arm. In the above construction there are two pivots which, to ensure freedom in the movement of the brush support, must be oiled from time to time, and sufficient weight in the support for the brush to cause the lever to oscillate against the tension of its spring, either from the-result of sudden jars to which parts about an automobile engine are constantly subjected, or as a result of the impact of the roller with irregular surfaces of the commutator. In fact commutators employing brushes of the character above referred to. are so irregularly worn as to accentuate the conditions above referred to, Jumping of the brush with relation to the commutator quite frequently causes an engine cylinder to miss lire alto-a gether, or a delay in the firing of the cylinder, thus interferring with the smooth running of the engine. I I

With the above conditions in mind, I have produced a timing device wherein the brush will be maintained in constant, continuous engagement with all sections of the commu'tator and wherein the working conditions will be such that there will be no irregular wear in said commutator.

A brush made in accordance with my invention is so constructed as to ensure accuracy in the closing of the circuit to the coils under all conditions and a continuity in the flow of the current for the entire length of the contact se ments of the commutator. Furthermore, the contact area between the brush and the commutator will be sufliciently great to ensure against sparking. The contact itself is so constructed as to avoid excessive wear-of parts, notwithstanding-the high speed of rotation of the roller of the brush, and the device is free from pivotal supports of all kinds which would require oiling to avoid undue wear thereon.

The invention consists in a timer for in ternal combustion engines embodying therein the combination with a commutator ring, of a brush adapted to be rotated in synchro' nism with the engine shaft, consisting of a hub, a radially extending housing having parallel side walls, a substantially cylindrical roller slidabl v and rotatably mounted insaid housing with its sides in substantial engagement with the sidewalls thereof, a spring in said housing having a normal tendency to thrust said roller through and be yond the open end of said housing, and a wear, plate between said spring and said roller, whereby scoring of the surface of said roller is prevented, said spring being held under tension by the enagagement of said roller with said commutator ring; and in such other novel features of construction and combination of parts as are hereinafter set forth and described, and more particularly pointed out in the claims hereto appended.

Referring to the drawings,

Fig. 1 is an elevation of a commutator ring and a brush embodying my invention associated therewith. on the line 11 of Fig. 3, a portion of the housing of the brush being broken away;

Fig. 2 is a detail vertical section through the brush; and

Fig. is a section on the line 3-3 of Fig. 1. Y

Like'letters refer to like parts throughout the several views.

In the embodiment of my invention shown in the drawings, a indicates an old and well known construct-ion of commutator housing carrying a commutator ring pro-- vided with the contact segments 1, 2, 3 and 4, each having associated therewith the usual binding post 1 2 3 and 4:. Said segments and said binding posts are insulated from each other and from the housing a by suitable insulating materialiiicluding a ring Ziwhich is recessed to receive said contact segments. Said housing and its commutator are adapted to be oscillated by means of asiiitable lever system connected with thelug c to advance or retard the spark. This general construction and arrangement is old and well known in the art and no claim of invention is made thereto;

Associated with said commutator is brush mechanism which is rotated 111;Sy1flchronism with the engine shaft, preferably by being mounted upon an extension thereof, which "is indicated at (Z in the drawings. Thisbrush comprises a hub 6 having a suitable slot therein adapted to co-operate with a pin 7 upon the shaft (Z soqas to facilitate the mounting and removing of the brush with relation to the shaft to cause it to rotate therewith.

The hub e'is provided with a radially extended housing g, the open top of which terminates adjacent the commutator ring, sufficient clearance being aiforded to avoid possible contact of the end of the housing with said commutator. v The chamber of the housing 9' is rectangular in section to accommodate the sub stantially cylindrical contact roller h and permit the free rotary movement of said roller and a reciprocatory movement there of radially of the hub c with the two-fold v object of limiting the rotary movement of said roller to an axis parallel to that of'said hub and permitting the roller to recede within the housing to fit the brush to the commutator ring and to compensate for irregularities iii the surface of said ring cooperating with the roll-er. 1 It isv to be observed that said roller /b has no arbors and no fixed axis of rotation, its axis of rotation being variable according to the variations from a true circle in the commutator ring, should such exist or develop, f Within the housing 9 is ajcoiled spring 2' which is normally'held under tension by the roller h as a result of its movem ntia- V war-(11 of said housing, a wear plate being interposed between said spring and the,p'e-- rin'ieter of said roller to avoid abrasion of the contact surface of said roller from the enact the tempered spring.

The spring 71 has suflicient strength to 7 The roller h possesses so little weight in itself that it will have little tendency toinove against the tension of said spring as a re suit of jars or jolts upon the vehicle, the

tendency toward displacement of the roller inwardly of the housing against the tension of said spring by such olts and ars being further minimized by the action of centrifugal force.

The housing 9 for convenience of manua facture has been made of soft metal, and.

since wear thereon will occur uponthe rear wall of the chamber therein as determined by the direction of rotation of thehousing, I provide said wall with a wear plate 70 against which the said roller will be thrust as a result of the frictional engagement thereof withthe commutator ring 3 To facilitate the assembling,handling'and mounting of the brush, the forward ant rear walls at the open end of the housing are. crimped slightly after 7 the; roller is mounted therein, so that said roller will be held against displacement by the inturned metal of said walls andthus pr vent displacement of the roller. Said crimped edges will not be subject to wear or interfere with the free rotationof sa d roller, since the in= ward movement of the roller, to ensure its engagement with the commutator ring, will prevent the engagement of the roller with said crimped portion while it is function a The operation of the herein ClGSU'lbBLl timing mechaiiism is suhstantiallyas follows lii assembling the brush in a timer, the casing a is removed andthe hub a mounted upon the shaft d by means of the pin f, said housing and its commutator r ng being then 1. i

replaced, the roller 71 being depressed against the tension ofthe spring z'so as to, bring this roller within and in engagement with the operative surface of 's'aid ring. As the roller ,thus recedes within said housing 9 the contact surface thereof will be engaged onl'v w th the wear plate 7' until the shaft (Z is rotated, whence this surface will also contact with the wear plate 7:; at the rear all of the opening in 'said h'ousing. ,Since the sides of the roller have afree running fitawith the parallel side walls of the opening in said housing, there ill be no 'stichfriction developed as will require any, lubrication otthe device, and thus the liabiiity of an on film being'fo'rmed upon 1, 2, 3 or 4: to the pistons 7 as x its

the contacts 1, 2, 3 and 4 is eliminated. As stated above, when the brush is assembled in the timer, the contact surface thereof does not engage the inturned forward and rear edges at the open end of the housing.

iVhen the spring 2' is tensioned in the manner above described, it will force the roller h outwardly with suflicient force to maintain it in constant engagement with the commutato ring so as to ensure accuracy in the timing of the ignition of the explosive charge in the respective engine cylinders, and maintain the circuit closed for a period determined by the length of each con tact segment. I have found in actual practice that severe jarring of the vehicle will have no tendency to cause the disengagement of said roller from the commutator ring, and that a roughened surface of said ring will not interfere in any way with the timely making and maintenance of a perfect contact. In fact I have found, when using a brush made. in accordance with my invention, with a badly corrugated commutator ring, that there was notonly no loss of, nor interruption in, the contact, but that with a continued running of the engine, the ring will be brought to a true smooth surface.

The constant thrust of the spring 2' and the constant engagement of the wear plate 7' with the roller h as a result of such thrust, ensures continuity in the ground connection through the brush and the shaft (i, there being no possibility or likelihood of the partial or complete insulation of these parts by reason of the presence of an oil film thereon. Furthermore the constant wiping action of the roller with said wear plate and with the wear plate k ensures bright, clean contact areas between the roller and the conducting medium for leading the current to said shaft d.

It is not my intention to limit the invention to the precise details of construction shown in the accompanying drawings, it being apparent that such may be varied without departing from the spirit and scope of the invention.

I have found the use of a roller h of cylindrical form capable of having rotary movement about the axis parallel with the axis of the shaft d to be absolutely essential in order to secure the'desired contact area with the commutator ring, and to avoid undue wear upon the ring.

A brush made in accordance with my invention is subject to very slight wear, and I have observed no material wear upon the commutator ring as a result of the engage ment of the brush therewith. Any such slight wear as does occur will be readily com: pensated for by the advance of the roller by the spring 2'.

The reduced wear upon the co-acting parts resulting from continued use of a brush made in accordance with my invention, will prolong the life of a timing mechanism and permit the inexpensive repair thereof in the event of ultimate excessive wear, since any loss of tension in the spring as would interfere with the desired continuous contact of the roller, which loss might result from a decrease in the diameter of the roller as-a result of wear, may be remedied by mounting a new brush upon the shaft cl and thus avoid the necessity for replacing of the casing a and its commutator ring.

Practice has heretofore demonstrated that wearupon the timer, such as to interfere with its proper operation, is evidenced upon the commutator ring and not upon the brush mechanism, thus requiring the replacement of the commutator. This conditon, however, is reversed in a timer embodying my invention, since repairs can be efiected by merely replacing a worn brush with a new one. s I have found in actual practice that engine troubles attributed to the carburetor have arisen by reason of the improper functioning of the timer, and that by the substitution of a brush embodying my invention, the apparent carburetor trouble has been entirely eliminated.

Having described the invention, what 1 claim as new and desire to have protected 'by Letters Patent, is

1. A timer for internal combustion engines embodying therein the combination with a commutator ring, of a brush adapted to be rotated in synchronism withthe engine shaft, consisting of a hub, a radially extending housing having parallel side walls, a wear plate for the rear wall of the opening in said housing with regard to the direction of rotation of the brush, a substantially cylindrical roller slidably and rotatably mounted in said housing with its sides in substantial engagement with the side walls thereof, the perimeter of said roller being adapted to engage said Wear plate as the brush is rotated, a spring in said housing having a normal tendency to thrust said roller through and beyond the open end of said housing, and a wear plate between said spring and said roller whereby scoring of the surface of said roller is prevented, said spring being held under tension by the engagement of said roller with said commutator ring.

2. A timer for internal combustion engines embodying therein a brush consisting of a hub adapted to be detachably mounted upon a shaft, a radially extending housing having parallel side walls, a wear plate for the rear wall of the opening in said housing with regard to the direction of rotation of the brush, a substantially cylindrical roller slidably and rotatably mounted in said housing with its sides in substantial engagement with the side walls thereof, and its axis parallel with the axis of said hub, a metallic spring in said housing having a normal tendency to thrust In witness whereof I have hereunto aiflxed said roller throughand beyond the open end my signature, 'in the presence 'of t sub 10 of said housing, and a Wear plate between scribing Witnesses, this 8th day of December,

said spring andsaid roller whereby scoring 1920.

of the surface ofsaid roller is prevented, V BERNHARD VOLKMAR. and said roller is caused to move toward a Witnesses: 1 commutator ring With which the brush is I F. T. WENTWOR H,

adapted to cooperate. FRIEDA KOEHLER.

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