US2851999A - Hydraulic engine - Google Patents

Description

Sept. 16, 1958 H. KRATZ v 2,851,999

HYDRAULIC ENGINE Filed Aug. 15, 1957 2 Sheets-Sheet 1 F/GJ - sept. 16, 1958 Filed Aug. l5, 1957 H. KRATZ HYDRAULIC ENGINE 2 Sheets-Sheet 2 f ICQ Qc ATTORNEY United States HYDRAULIC ENGINE Hans Kratz, Duisburg, Germany, assigner to Demag- Baggerfabrik G. m. b. H., Dusseldorf-Benrath, Germany The present invention relates to tluid pressure engines and more particularly to engines which are driven` by a tiuid. such as a hydraulic liquid under pressure.

Engines of this type at the present time have several disadvantages such4 as their great expense and the fact that they are composed of numerous parts which` cause failure in the operation of the engine rather frequently. Furthermore, such engines cannot always beI driven. at as low a speed as desired, and furthermore they. cannot always be operated with the desired uniformity and evenness because of the fact thatv with some of these engines the fluid pressure engages the entire cross section of a piston during one part of the operation andonly a piston ring during another part of the operation.

One of the` objects of the present invention is to overcome the above drawbacks by providing a fluid pressure engine which will operate evenly and uniformly without providing dijerent areas to be engaged by the fluid under.- pressure at different parts of the cycle of operation'.

Another object of the present invention is to provide a fluid pressure engine which is of an extremely simple construction with a minimum number of parts such as trans; mission gears and the like, so that the possibility of failures in operation is reduced.

A further object of the present invention is to provide an engine of the above type Iwhich has anelongated configuration enabling the engine to be located without. diiiiculty within the space enclosed by a track of a vehicle such as a tractorV or other heavy vehicles which are provided with endless tracks which must be rotated forv pro pelling-the vehicle.

With the above objects in viev/thefpresent invention includes in a fluid-pressure engine a pairof coaxial piston members. and a pair ofcoaxial cylinder'members which respectively slidably-receive the piston members. The engine further includes a bar and a ring means. surrounding and slidably engaging the bar and beingjturnable: about the axis thereof. This ring means is located be.- tween and fixedto one ofthe pair of members for maintaining this one pair of members in spaced coaxial relation with respect to each other, and a rod means is x'ed to the other of the pair of members for maintainingfthe other pair of members in spaced coaxial relation withrespect to each other. A crank means is operatively connected with the other pair of members, and1 a passage means is formed in theV bar. andy ring means. and-communicates with the interiors of the cylinders for. directing fluid under pressure `to theinteriors of the cylinders and for leading fluid away from the interiorsof the cylinders. Thus, with this construction the reciprocation of the other pair of members with respect to the one pair of members will drive the crank means and the turningof the crank means will cause the two pairs of memberstogether with the ring means to turn` in an oscillatory fashion with respect to the bar. A

The novel-features which areconsidered as character-V isticfor thei invention are set forth in particular in the appendedclairns. The invention itself, (however, bothers? atent rice to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specic embodiments when read in connection with the accompanying drawings, in which:

Fig. 1 is a plan view of an engine according to the present invention;

Fig. 2 is a longitudinal sectional view taken along line 2--2 of Fig. l in the direction of the arrows;

Fig. 3 shows the engine of the invention located within the space surrounded by a track of a vehicle; and

Fig. 4 shows another embodiment of an enginev according to the present invention.

Referring to the drawings, the engine of the invention includes a support means, in form of a base plate 1 provided with a pair of upstanding portions 1a and 1b shown in Figs. l and 2. The portion 1a of the support means iixedly carries a bar 2 which is of cylindrical cross section, so thatl this bar 2 remains stationary with respect to the support means. A pair of ring means 3 surround and slidably engage the bar. 2 at the opposite sides of the portion 1a of the support means, respectively, and the pair of ring means 3 are each turnable about the axis of the bar 2 so as to oscillate with respect thereto in a manner described below. Each of the ring means 3 is located between and xed to a pair of piston members 4a and 4b so that these piston members 4oz. and 4b are maintained by the ring means 3 in spaced coaxial relation with respect to each other. A pair of cylinder members 5a and 5b respectively slidably receive each pair of piston members, and it will be noted that each pair of cylinder members is respectively provided with closed ends directed away from each other and open ends directed toward each other. Suitable sealing glands 6 are carried by each cylinder for closing off the interior thereof from the outer atmosphere `while maintaining each cylinder in Huidtight slidable engagement with the piston therein.

A rod means is connected to each pairV of cylinders for maintaining the same in spaced coaxial relation with respect to each other, and this rod means is shown in Fig. 2 as taking the form of a pair of elongatedparallel. rods 7 respectively extending through bores of4 outwardly. directed flanges of the cylinders and being tixed thereto by the nuts shown in Fig. 2, the flanges engaging shoulders of the rods '7.

A crank means 10 is rotatably supported by the portion 1b of the support means, and this crank meansltl is provided with a pair of oppositely directed crank pins ti'andr 9 which are respectively connected operatively with the two pairs of cylinders in the manner shown in Figs; l and 2. Furthermore, a flywheel 11 is connected to the crank means 10 for rotation therewith.

A passage means is formed in the bar 2 and the pair of ring means 3 for leading fluid under pressure to andfrom the interiors of the cylinders so that these cylindersreciprocate with respect to the pistons and drive the crank means. The passage means is in the form of a pair of transversebores 2b formed inthe bar 2 at each of the portions thereof which are respectively surrounded by the ring means 3, and each pair of transverse bores 2b are separated from each other by a transverse portion of the bar having a predetermined thickness.

of the bar a pair of bores 3a formed in each ring means 3, and it will be noted from Fig. 2 that each bore 3a has.

Furthermore, the. passage means includes at diametrically opposed-portions asesor-:v9

formed with a pair of axially extending bores 2a communicating with the transverse bores 2b, and the pair of axial bores 2a respectively communicate with a pair of conduits l?. (Fig. l), one of these conduits l2. leading duid under pressure to the bar and the other of the conduits carrying fluid away from the bar.

In the position of the parts shown in Fig. 2 both of the bores 3a are closed off from and do not communicate with the bores 2b so that at the particular moment of the operation illustrated in Fig. 2 the liuid cannot flow to or from the interiors of the cylinders shown in Fig. 2. However, as soon as the crank means starts to turn one of the cylinders shown in Fig. 2 will communicate with the fluid under pressure while the fluid in the other cylinder `will discharge therefrom.

In order that the engine will at all times start by itself as soon as fluid under pressure is delivered thereto the crank pins 8 and 9 are angularly displaced by 90 with respect to each other so that in this way although the engine may start with one of the pairs of pistons in the angular position shown in Fig. 2 the other pair of pistons will be in a different angular position prepared to direct iiuid under pressure to one of the cylinders so that the engine will always start.

Fig. 3 diagrammatically illustrates a vehicle 2t) pro vided with a track 2l which must be moved in order to propel the vehicle, and the engine 22 is diagrammatically illustrated in the space surrounded by the track 21, this engine 22 being the above-described engine of the present invention. Because of its elongated construction the engine of the present invention can easily tit into the relatively long narrow space surrounded by a track such as the track 21 so that the structure of the present invention is particularly suited for propelling such track.

It will be noted that with the structure of the invention the liuid under pressure engages the same cross sectional area of the pistons at all times so that the operation of the engine is even and uniform, and furthermore the structure of the invention is quite simple so that the possibility of failures in operation is greatly reduced.

Of course, the conduits 12 communicate with a suitable pump driven from any desired source of power and with a reservoir for the liquid, the liquid being delivered from the reservoir by the pump to one of the conduits 12 and being returned by the other conduit l2 back to the reservoir.

It is not essential that the pistons be connected with the ring 3 while the cylinders are connected with the crank 1t), and Fig. 4 shows an engine according to the present invention where the piston and cylinder arrangement of Figs. 1 and 2 is reversed. Thus, as may be seen from Fig. 4 the cylinders 5a and 5b are fixed with the ring 3 as by being formed integrally therewith, and the pistons 4a and 4b are respectively slidable in these cylinders and are axially immovable with respect to each other as the result of their interconnection by the rods 7, the sealing glands 6 providing duid-tight cooperation between the cylinders and the pistons in the manner shown in Fig. 4. rlhe crank pin 9 is connected with the pistons. Of course, the structure shown in Fig. 4 is duplicated on the other side of the flywheel 11 in` the same way as with the embodiment of Figs. l and 2 and the assemblies on the opposite sides of the flywheel are angularly displaced with respect to each other by 90, as was described above in connection with Figs. l and 2. It is apparent that the embodiment of Fig. 4 will operate in the same way as the embodiment'of Figs. l and 2 and will produce the same results, the only diiference being that in the embodiment of Figs. l and 2 the cylinders reciprocate on the pistons while in the embodiment of Fig. 4 th pistons reciprocate in the cylinders.

It will be understood that each of the elements described above, or two or more together, may also nd a useful application in other types of engines differing from the types described above.

While the invention has been illustrated and described as embodied in fluid pressure engines, it is not intended to be limited to the details shown, since various ineditications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be secured by Letters Patent is:

l. In a fluid pressure engine, in combination, a pair of coaxial cylinder members and a pair of coaxial piston members respectively slidable within said cylinder members; a bar; ring means surrounding and slidably engaging said bar and being turnable about the axis thereof, said ring means being located between and fixed to one of said pair of members for holding said one pair of members in spaced coaxial relation with respect to each other; rod means extending between and fixed to the other of said pair of members for holding said other pair of members in spaced coaxial'relation with respect to each other; and passage means formed in said bar and ring means and communicating with the interior of said cylinders for directing pressure fluid to and from the interior of said cylinders.

2. In a fluid pressure engine, in combination, a pair of coaxial cylinder members and a pair of coaxial piston members respectively slidable within said cylinder members; a bar; ring means surrounding and slidably engaging said bar and being turnable about the axis thereof, said ring means being located between and fixed to one of said pair of members for holding said one pair of members in spaced coaxial relation with respect to each other; rod means extending between and fixed to the other of said pair of members for holding said other pair of members in spaced coaxial relation with respect to each other; passage means formed in said bar and ring means and communicating with the interior of said cylinders for directing pressure fluid to and from the interior of said cylinders; :and crank means operatively connected with said other pair of members to be driven by the reciprocation of said other pair of members with respect to said one pair of members.

3. In a fluid pressure engine, in combination, a pair of coaxial pistons and a pair of coaxial cylinders respectively slidably receiving said pistons; a bar formed with a pair of transverse bores passing therethrough and separating from each other by an elongated transverse portion of said bar of predetermined thickness; ring means surrounding and slidably engaging said bar at the portion thereof formed with said transverse bores and being turnable :about the axis of said bar, said ring means being located 'between and lixed to one of said pair of members for maintaining the same in spaced coaxial relation with respect to each other and said ring means -being formed -at diametrically opposed parts of said bar with a pair of bores each of which has a diameter not greater than the thickness of the transverse portion of said bar located between said bores thereof and said bores of said ring means alternatively communicating with said `bores of said bar during oscillatory turning of said ring means with respect to said bar, said one pair of members being formed with hollow interiors, respectively, which respectively communicate with said bores 0f said ring means; rod means connected to the other pair of members for maintaining said other pair of members in spaced coaxial relation with respect to each other; a pressure conduit and a discharge conduit respectively communicating with said transverse bores of said bar for respectively leading fluid pressure to and discharging iluid from said bores of said bar; and crank means operatively connected to said other pair of members to be driven by reciprocation thereof with respect to said one pair of members.

4. In a uid pressure engine, in combination, -a bar; ring means surrounding and slidably engaging said bar and being turnable with respect thereto; a pair of coaxial pistons xed to and extending from diametric-ally opposed portions of said ring means; a pair of coaxial cylinders into which said pistons respectively slidably extend, said cylinders respectively having closed ends di-v rected away from each other and open ends directed to- Ward each other; rod means iixed to said cylinders for maintaining the same coaxially spaced from each other; crank means operatively connected to said pair of cylinders to be operated by reciprocation of said cylinders with respect to said pistons; and passage means formed in said bar and ring means and communicating with the interiors of said cylinders for leading fluid under pressure to and from said cylinders.

5. In a fluid pressure engine, in combination, a bar; ring means surrounding and slidably engaging said bar and being turnable with respect thereto; a pair of coaxial pistons iixed to and extending from diametrically opposed portions of said ring means; a pair of coaxial cylinders into which said pistons respectively slidably extend, said cylinders respectively having vclosed ends directed away from each other and open ends directed toward each other; rod means tixed to said vcylinders for maintaining the same coaxially spaced from each other; crank means operatively connected to said pair of cylinders to be operated by reciprocation of said cylinders with respect to said pistons; and passage means formed in said bar and ring means and communicating with the interiors of said cylinders for leading tluid under pressure to and from said cylinders, said passage means being in the form of a portion of said bar formed with a pair of spaced transverse bores separated from each other by a transverse portion of said `bar of predetermined thickness and a pair of additional bores formed at diametrically opposed parts of said bar in said ring means, the additional bores in said ring means having a diameter no greater than the thickness of the transverse portion of said bar located between the bores of said bar, and said pistons respectively being formed with axial bores respectively communicating with said bores of said ring means and with the interiors of said cylinders, whereby when a uid pressure line communicates with one of the bores of said bar and a fluid discharge line communicates with the other bore of said bar said bores of said ring means will alternatively communicate with said bores of said bar to alternately lead uid under pressure to said cylinders in order to reciprocate the same with respect to said pistons.

6. In a fluid pressure engine, in combination, support means; a bar lixedly carried by said support means; a pair of ring means respectively slidably surrounding said bar and being turnable about the ax-s thereof; a pair of pistons respectively xed to diametrically opposed parts of each of said ring means and extending coaxially therefrom; a pair of cylinders respectively slidably receiving each pair of pistons; rod means interconnecting each pair of cylinders for maintaining each pair of cylinders in spaced coaxial relation with respect to each other; crank means rotatably carried by said support means and connected operatively with both of said pairs or cylinders; and passage means formed in said bar and said pair of ring means and respectively communicating with the interiors of all of said cylinders for leading uid under pressure to and from said cylinders so that said cylinders reciprocate in order to drive said crank means.

7. In a lluid pressure engine, in combination, support means; a bar lixedly carried by said support means; a pair of ring means respectively slidably surrounding said bar and being turnable about the axis thereof; a pair of pistons respectively xed to diametrically opposed parts of each of said ring means and extending coaxially therelfrom; a pair of cylinders respectively slidably receiving each pair of pistons; rod means interconnecting e-ach pair of cylinders for maintaining each pair of cylinders in spaced coaxial relation with respect to each other; crank means rotatably carried by said support means and connected operatively with both of said pairs of cylinders; the portions of said pairs of cylinders which are connected to said crank means being angularly displaced with respect to each other by about the turning axis of Said crank means; and passage means formed in said bar and said pair of ring means and respectively communicating with the interiors of all of said cylinders for leading fluid under pressure to and from said cylinders so that said cylinders reciprocate in order to drive said crank means.

8. In a fluid pressure engine, in combination, support means; a bar tixedly carried by said support means; a pair of ring means respectively slidably surrounding said bar and being turnable about the `axis thereof; a pair of pistons respectively fixed to diametrically opposed parts of each of said ring means and extending coaxially therefrom; a pair of cylinders respectively slidably receiving each pair of pistons; rod means interconnecting each pair of cylinders for maintaining each pair of cylinders in spaced coaxial relation with respect to each other; crank means rotatably carried by said support means and connected operatively with both of said pairs of cylinders; passage means stormed in said bar and said pair of ring means and respectively communicating with the interiors of all of said cylinders for leading fluid under pressure to and from said cylinders so that said cylinders reciprocate in order to drive said crank means; and ywheel means connected to said crank means -for rotation therewith.

References Cited in the le of this patent UNITED STATES PATENTS 373,880 Case Nov. 29, 1887 373 922 Case Nov. 29, 1887 479,012 Moss July 19, 1892

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