US2642748A - Mechanical movement in hydraulic motors - Google Patents

Description

June 23, 1953 l P. wlDMER MECHANICAL MOVEMENT IN HYDRAULIC MOTQRS Filed Dec. 1. 1949.

Patented June 23, 1953 MECHANICAL MOVEMENT IN" HYDRAULIC Mo'roas Leo Peter Widmer, Winterthur, Switzerland, as-

signor to` Schweizerische Lokomotiv-k Iund Maschinenfabrik, Winterth'un Switzerland Application December 1, 1949, serial No. 130,385

kIn Switzerland January 15, 1949` My present invention relates to improvements in expansible-chamber motors in which the pistons and cylinders are disposed starlike about a crankshaft in a stationary casing, the cylinders are oscillatable on pins which are parallel tothe crankshaft axis, and in which the pressurized duid is fed to the cylinders through the said pins, while the pistons engage a common ring which is mounted on the crank pin.

In such motors it is known to rigidly secure the said ring to one of the pistons and thus guide the ring by means of one of the swinging cylinders. it further is known to so guide said ring by a separate means that each point thereof describes a circle of a diameter equal to that of the crank circle, i. e. so that all the pistonssuccessively perform exactly the same movement. In the latter case, the torque produced on the crankshaft and the rotary speed of the crankshaft is more uniform than in the former case, but such construction is more expensive and requires more space.

in the motor according to my present invention, the said ring is provided with a series of circumferential V-cuts, of a number equal to that of the cylinders, each cut being engageable with at least one of the pistons. The latter for such purpose are provided with a Wedge-shaped footportion of which the knife edge is parallel to the .axis of rotation cf the crankshaft. Such arrangement requires a relatively small space vand. affords amore uniform rotary speed of the crankshaft.

One form of my present invention is shown in the drawing, in which- Fig. l shows a vertical section on the line I--I of Fig. 2,

Fig. 2 is another vertical section on the line I-II of Fig. 1,

Fig. 3 shows an elevation through a modified piston retaining ring,

Fig. 3A shows a vertical section on the line iii-HI of Figure 3, and

Fig. fi is a perspective view of a piston-foot portion conforming to the ring member shown in Figs. 3 and 3A.

In a stationary casing I, a crankshaft 2 is rotatably mounted by means of antifriction-bearings 3 and ii. The motor torque may be derived from the crankshaft end 5. A ring member 9 is rotatably mounted on a crankpin 1 by means of l 2 a needle-bearing 8, and is provided with nine V-cuts Il in accordance with the nine cylinders shown. Said cuts are engaged by the Wedgesha'ped foot-portion I2 of a piston I3 each, the knife edge of portion I2 being parallel to the axis of rotation of'crankshaft 2. The piston portion I2 has two lateral shoulders I2a which project from the piston stem. Two ring members I I engage the shoulders I2a of all the pistons and prevent them from leaving the cuts I0 of ring 9.

In order to permit installation of the ring 9 as an integral member, the crankshaft, as known, in the art, comprises two parts which are interconnected through a screw 6. Each.A piston I3 is guided in a cylinder I5 which hasa crossbore I6 by means of which it is oscillatably mounted on a pin I1 fixed to casing I. Each pin I1 comprises two longitudinal bores I8, I9 and two bores 20, 2l which open into bores I8, I9 and extend in an approximately radial direction to the center 23 of the stationary 'casing `I. The said bores 20, 2| in each pin I1 -serve for controlling the fluid inflow and outflow to and from the cylinders I5 in a manner similar to that shown and described in my pendinggU. S. patent application Ser. No. 686,027 of July 24,A 1946, now Patent No. 2,507,361, issued May 9, 1950. For such purpose all the bores I8 which at their ends are plugged lby caps 22, open to radial ducts 24 which communicate p with a iirst annular chamber 25, the latter being supplied with fluid under pressure from the outside through a pipe 21. All the cylinders I5 disposed on the right of a plane II--II (Fig. 1) therefore communicate with pipe 21, thus being under pressure and producing a torque on crankshaft 2. A

The' bores I9, which also are plugged by further caps 22, open to radial bores 28 which communicate with a second vannular chamber 29 to which a return pipe 30 is connected. An annular cover 3l is secured on casing I for closing the chamber 29 toward the insideof the motor. All the Ycylinders I5 disposed on the left of plane II-II (Fig. 1) communicate with return pipe 30 through the bores and ducts 2 I, I9, 28, 29 and allow the spent fluid to flow out of the cylinders.

The mode of operation of the motor substantially springs from the above description, it being readily seen that due to the eccentric-ity of crank pin I relative to crank-shaft 2, thelatter is roin counterclockwise direction, the succeeding piston I3a assumes a similar position relatively to crankpin 1, the wedge of piston I3a abuts against the lower side of the appurtenant V-cut I-I), i. e. piston I3a now guides the ring 9. It therefore will be readily seen that during oneV full revolution of the crankshaft, all` the pistons |31 alternatingly guide the ring 9 in like manner as. does 20 the right-hand horizontal piston in Fig. 1.

Any tendency of wedge I2` to jumpout of cut' I0, as induced through a torque acting on the ring 9, is opposed by the fluid pressure` acting on the piston. Such tendency also may be opposed through the shape of the cuts. in that the angle of the V preferably is made slightly less than 90.

Figs. 3 and 3A show a modication of the two ring members II ofI Figs. 1- and 2,4 which also serves for preventing the pistons I3 from jumping the cuts I0. Instead of having a collar llc of constant thickness (as shown in Figs. 1, 2), the ring member I Ia shown in'Fig. 3 is provided with milled recesses IIa' of circular cylindrical form. The centersv Ila" of said recesses coincide with the bottoms of the V-notches I0 in ring 9, as shown in Fig. 3. The: pistons I3 in such case are provided with twoA arcuate shoulders I2a of which.- the diameter corresponds to that of the recessesy I'Ia/ in Fig. 3. Infsuch modication (Figs. 3, 4), the retaining rings. I Ia must be xed in the proper positionwithrespect to the star ring 9.Y A

The number4 ofv pistons and cylinders may be different from nine. By making the. crank pin Iv longer thanV shown in Fig. 2, aA second set of cylinders and pistons. may be. provided beside the set shown.4 Insuchcase, the pins I1 may be located, e. g., intermediate the pins I1 of the set shown, on the stationary casing I.

What I claim as new and desire to secure by Letters Patent, is:

1. In an expansible-chamber type motor in which the pistons and cylinders are disposed starlike about the crank-shaft and the pistons engage a commonstar ring mounted on the crank pin, the improvement which comprises providing the said star ring with V-cuts of a number equal to that of the cylinders, and wedgeshaped foot portions on the pistons adapted to engage the said cuts, the knife edge of the piston foot portions being parallel to the axis of rotation of the crankshaft.

2. The improvement defined by claim 1, wherein the two sloping edges of each cut includes an angle of less than 3. A hydraulic motor comprising a crank shaft, a plurality of cylinders disposed starlike aboutv the crankshaft, pistons movable in said cylinders, a star ring mounted on the crankshaft, each piston being provided with a wedgesha'ped footl portion having a knife edge parallel tothe axis of rotation of the crankshaft, said star ring' being provided with a plurality of V-cuts each engaging the foot portion of one piston, each piston being provided with opposite axial-ly extending shoulders adjacent to the foot portion thereof, and two opposed ring members surrounding the crankshaft laterally of said star ring, saidring members engaging the shoulders of the pistons for retaining the pistons and preventing the wedge-shaped foot portions from jumping out of said V-cuts in the star ring.

4. The improvement, defined by claim 3, wherein each retaining ring is provided with circularly curved recesses, each piston shoulder being of circularly curved form of the same radius as said recesses, the centers of curvature of the said recesses and shoulders being situated on a circle which is concentric with the crankpin and comprises points of the knife edge of the wedge-shaped piston foot portions.

LEO PETER WIDMER.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,590,225- Boisset June 9, 1926

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