US 2513083 A
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June`27, 1950 s. B. EcKERT WOBBLER DRIVE MECHANISM Filed May 24, 1945 :s sheets-sheet 1 June 27, 1950 s. B. ECKERT 2,513,083
WOBBLER DRIVE MECHANISM Filed May 24, 1945 3 Sheets-Sheet 2 Wir/V555.'
@Mx/f June 27, 1950 s. B. EcKER'r 2,513,083
woBBLER DRIVE MECHANISM Filed May 24, 1945 3 Sheets-Sheet 3 Patented June 27, 1950 UNITED STATES PATENT OFFICE 2,513,083 WOBBLER DRIVE McHf-NISM Samuel B. Eckert, Haverford, Pa. Application May 24, 1945K', seriaiNo. "595,593
It is Well understood that within reasonable limits increasing the compression ratio of an internal combustion engine greatly improves its power output and fuel efficiency. If, however, such an engine is designed for a compression ratio of- (say) 7 to 1 and is then operated under normal conditions `with the buttery valve only partially open, the .average compression ratio at which the engine operates is only about onequarter of its full capacity. It has Ibeen calculated, as well as determined by experiment, that with such reduction in compression ratio the eliciency of the engine is reduced approximately one-half, involving serious waste of fuel.
The object of my invention is to adjustably Vary the stroke of the piston (thereby varying the charge admitted to the cylinder) and at the same time maintain constant the ratio of volumes of the cylinder at the two end strokes of the piston; that is, to maintain, at al1 loads, a constant compression ratio and hence uniform maximum eiiciency and fuel economy.
The invention is embodied in an engine of the so-called crankless opposed piston type, in which adjusting means are provided to (l) vary the position of the piston at the end of its instroke to thereby vary the charge of combustible 'gases admitted to the cylinder and (2) at the same time vary the length of the stroke of the piston so that the charge drawn into the cylinder will always be compressed to the same predetermined pressure.
A preferred embodiment of the invention is shown in the drawings, in which- Fig. 1 is a longitudinal view, partly in section,
of the engine.
vFig. 2 is an enlarged longitudinal sectional view of the mechanism, including the piston-stroke adjusting device, between the pistons and the main driving shaft.
Fig. 3 is a cross-.sectional View on the line 3.-3 of Fig. 2.
Fig. 4 is a cross-section on the line 4 4 of Fig'. 2.
Fig. 5 is a diagram showing how the desired compression ratio may be maintained at dierent adjustments controlling piston stroke.
The engine is, as hereinbefore stated,.of the opposed piston type and comprises cylinders a, Within each of which reciprocates opposed pistonsb. No mechanism is shown for actuating the inlet. and exhaustr valves lz' since these may be ofthe conventional type actuable :by the conventionaltype of half timeV camshaft and valve lifts. IElachl piston is. through. a connecting rod. cg. at-
5 Claims. (Cl. 74;-60)
taches-l', through `'a universal joint, with a collar or wobbl'er element d at `the corresponding er-l'cl-v of the engine. This collar is U-shaped in cross-sec'- tion and embraces the periph-eral portion of arotatable Clisi?v '9.
On an enlargement g of the hollow main driv# ingl shaftjy (see Fig. 2) 'are slidable two sleeves i and'v i. lExtending through longitudinal slots k in the enlarged part g of the shaft 'j 'are' cross'- hea'ds m and n secured to the sleeves i and j respectively. These sleeves are thus made to rotate with the shaft.Y The cross-heads are machinefinished so that they may freelyA move through the stot lc, but lcannot rotate relative tothe shaft. The disc e is pivoted, at its center, 'to the 'crosshead lTo the sleeve 7' is secured a'n arm o and to the disc e is secured anA arm p, these armsv be"- injg connected' by alink r.
Secured to each collarv d are pins t slidable a slotted arm. secured to the engine casing, thereby neutralizing the tendency of the colla-r d to revolve with the disc e.
From the foregoing description it will be understoody that reciprocationo'f the pistons effects rotation 'ofthe disc e, cross-heads m, n, sleeves 1' and the mainfdrive. shaft f. y. 1
The centers ofv crosslheads ym, n; are threaded to receive thescrew-threaded portions o andtv; respectively, 'of a shaft s` that "eiftends'through' th hollow, main drive shaft. `Shaft `s isdri'ven from a small controllable motor yg. which is controlled from the throttle n'ot shown). ,The t'l'ireadsv D and w are of different pitch, the thread o beine of steeper pitch; soi, that, when the shaft s isfrutatedvn. one direction or the otl'1e1'-, while 'both cross-heads are moved in the same'direction, one will4 mIQYe a further; distance thanthe other. The e'ect; will be. to. swing 4the 'disc e on its pivot in one or the otlrie'i direction,therebyincreasing or reducing the length of.l stroke of the pistons. The shafts may be h elfd? in place by any suitable means, kfor example,r by a thrust collar z, a secured' to the shaft. i y
All the mechanism hereinbefore described is duplicated at both end-s of the v engine, the. only difference -loeingf thatwthe two pairs: of threads. at ormositet ends of, the shaft s; are respectivelyrigjfht handV and left; hand; threads:,.so that, when; the shaft ys is; rota-'ted one` oli-reation;` or the other, theV two vdiscsl will; ibe swung in, opposite direcL tions. y
The-threadiio is. 'of larger diameter thanthe threadawi.sorth-atwhenthe cross-head m is.'moved such: distance; towardf` theL crosseheadi `as.l tot sur;
not engage the thread on cross-head m.
From the foregoing description it will be understood ythat the pitch of` each of the threaded portions of shaft s is so arranged as to insure p such movement of the disc e as will vary the volume of combustible gases admitted into the cylinders a. and at the same time insure that in the reciprocation of the pistons the compression space is varied in such a way as to maintain the same compression ratio regardless `of the volume of the charge taken into the cylinder. This will be clearly understood by reference to Fig. 5. In this figure the discs e are adjusted, as shown in full lines, to allow a relatively Along stroke of the pistons tively large charge. The distance between the pressure face of each piston and the `midway point of the cylinder is shown, at the outstroke, as adistance of 6 units of measurement and at the instroke as l unit of measurement, giving a3 compression ratio of 6 to 1. When the. disc is adjusted to the dotted line position to thereby admit a smaller charge, the distances between the pressure face of each piston and the midway point of the cylinder are reduced (for eX- ample) to 3 units at theoutstroke and 71/2 unit at the instroke,l giving the same compression ratio of 6 to 1. This ratio is maintained constant regardless of the predetermined length of stroke of the piston.
It will be understood that my improved construction isk sharply distinguishable from' constructions that are adapted to be adjusted to vary the compression ratio through varying the length of stroke, my improvement being intended and adapted to avoid any variation in the compression ratio, that is, vto maintain con-` stant the relationship between the volume of the cylinder with the piston at the bottom of its stroke' and the volume ofthe cylinder with the piston at the top of its stroke, thereby enabling the engine to at all times operate at maximum efficiency and economy.
.What Iclaimand desire Patent is: v
1. In an internal ycombustion engine comprising'a rotatable engine shaft, two sets of opposed cylinders disposed about said shaft andhaving their axes parallel thereto, wobbler elements toward opposite ends of and non-rotatable with the shaft, one for each setof cylinders, members toward opposite ends of and rotatable with the shaft and in their rotation imparting movement to the wobbler elements, and pistons reciprocatory in said cylinders and operatively connected with said wobbler elements; the improvement which comprises two pairs of cross-heads near to protect by4 Letters ,opposite ends of the shaft, slidable along, but
heldfrom rotation relative to, the said shaft, means, including screw threads of dierent pitch engaging the two cross-heads of a pair, adapted to move the two cross-heads of each pair simultaneously in the same direction but to different distances, eachof saidrotatable members Vhaving a pivotal connection with one ofthe two cross-heads vat the corresponding end' of the shaft, and connections between each rotatable member and the other cross-head at the'correspending end of the shaft effective to change the .angle of the wobbler velement ywhen said cross-heads are so moved. 2. Inan internal combustion engine comprising a rotatable engine shaft, two sets of opposed cylinders disposed about said shaft and having to thereby admit a relatheir axes parallel thereto, wobbler elements toward opposite ends of and non-rotatable with the shaft, one for each set of cylinders, rotatable members toward opposite ends of and rotatable with the shaft, pistons reciprocatcry in said cylinders and operatively connected with said wobbler elements; the improvement which comprises two pairs of sleeves, one pair at each of the opposite end portions of the shaft, slidable upon and rotatable with the shaft, each of said rotatable members being pivotally connected with one sleeve of the pair of sleeves at the corresponding end portion of the shaft, a link connection between each of said rotatable members and the other sleeve of the corresponding pair, and means including screw threads of dierent pitch engaging the two sleeves of a pair, adapted to simultaneously slide the corresponding two pairs of sleeves in opposite directions while at the' same time sliding the two sleeves of each pair different distances in the same direction.
3. In an internal 1combustion engine comprising a rotatableengine shaft, two setsI of opposed cylinders disposed about said shaft and having their axes parallel thereto, wobbler elements toward opposite ends of and non-rotatable with the shaft, one for each set of cylinders, members toward opposite ends of and rotatable with the s-haft and in their rotation imparting wobbling movement to the wobbler elements, pistons reciprocatory in said cylinders and operatively connected with said wobbler elements; the improvement which comprises two .cross-heads slidable along, but held from rotation relatively to, said shaft, means so pivotally connecting each rotatable member with both corresponding crossheads that relative movement of said cross-heads along the shaft swings such rotatable member and its corresponding wobbler element to change their angular position on the shaft, a second shaft extending within the main shaft having near each end two threaded portions engaging interior threads in the two cross-heads respectively, said threaded portions being of different pitch to thereby, when said second shaft is rotated, move said cross-heads in the same direction but to different distances.
4. The construction defined in claim 3 in which said two threaded portions are of different` diameters so that the threaded portion of smaller diameter engaging one cross-head can enter the threaded interior of the other cross-head without engaging the same.
5. The construction dened in claim 1 in which each rotatable member is pivotally connected at its center with one of the -corresponding crossheads and in which the connection of such rotatable member with the other corresponding cross-head comprises a sleeve carried by the last named cross-head and slidable on the shaft, an arm on the wobbler element between its center and periphery, an arm on said sleeve, and a link -connectingsaid arms.
SAMUEL B. ECKERT.
REFERENCES CITED The following references are of record in the file of this patent:
UNITED STATES PATENTS