US2618253A - Radial engine - Google Patents

Description

Nov. 18, 1952 G. D. ANGLE 2,618,253

RADIAL ENGINE Filed June 15, 1947 2 sHEETs sHEET 1 0 INVENTOR Glenn .3. 44229459 M ATTORNEYS Nov. 18, 1952 G, D, A LE I 2,618,253

RADIAL ENGINE Filed June 15, 1947 2 SHEETS-SHEET 2 INVENTOR GZezznflAzyZ'e ATTORNEYS Patented Nov. 18, 1952 UNITED STATES PATENT OFFICE 2,618,253 RADIAL ENGINE Glenn Angle, Thomaston, Connaassjignortoi The; N Br a ne o p n w Britain, Conn, a corporation of Connecticut Application-June 13, 1947, Serial No. 754,556

scams. (o1. fee-19s) My invention relates to reciprocating engines, and in particular to radial internal-combustion engines as employed in aircraft.

A primary object of theinvention' is to provide a. simple radial-engine construction that will permit improved methods of assembly.

Another object is to provide an'improved engine construction that 'ma'y be fabricated at a reduced cost and that will be inexpensive to maintain.

A further object is to provide a radial-engine construction that will permit the assembly of all pistons and of their linkagesto' a central cluster or so-called big-end, without'and before introduction of the crankshaft.

Other objects'and' various further features of the invention will be pointed out or will occur to those skilled in the art from a reading of the following specification in conjunction with the drawings included herewith. In said drawings:

Fig. 1 is a simplified sectional view of parts of a radial engine incorporatingfeatures of the invention, the section being taken in the plane of the cylinder axes;

Fig. 2 is another view of the engine of Fig. 1, taken substantially in the plane 22 of Fig. 1;

Fig. 3 is a view similar to Fig. 2, but with certain assemblies separated to illustrate features of the invention;

Fig. 4 is a vertical-sectional view, in consider ably greater detail, of parts of a radial engine illustrative'of a preferred embodiment of the invention; and

Fig. 5 is an enlarged end view of a part of'the arrangement of Fig. 4, shown prior to its assembly with anotherpart;

Up to the present time; at least three distinct methods have been employed for the arrangement and assembly of the major components of radial engines, and it is believed that a better understanding of the invention may be had after a brief review of these three methods.

According to the first, and perhaps the oldest,

made to protrude through the respective openingsf'or the cylinders on the outer rim of the crankcase to enable the assembly of the pistons. The removable cylinders,werethen slipped over the pistons and bolted down upon the pads provided for their flanges on the crankcase. In brief, this method involved an assembly of each major unit during final assembly;

The second method, which has been adopted by a number of prominent manufacturers for the past several years, differed from the first mainly in that the crankshaft was made in two pieces, while the master connecting .rodwas' made with a solid-ring big-end. In large engines this proved to be better than the first method for the reason that the solid-ringbig-end of themaster rod provided better bearing conditions on the whole and occupied. less space, particularly from thepoint of view of clearance within the crankcase; To facilitate the use of this construction, the main crankcase is made in two sections joinedrin the plane ofthe cylinders; with each section carrying a bearing for the assembled crankshaft. Foran accurate fitting of cylinders to the crankcase, this-second method required fastening thetwo pieces together during machining. Aside from the problems of making the crankcase in two pieces, this method, offered certain advantages as compared with the first general arrangementdescribed. V g

The third method forms the subject of my Patent1 ,6'70,294, issued May 28, 1928. According to this third method of construction,'all connecting rods could be assembled to the crankshaft prior to incorporation in the crankcase. The construction thus permitted a simplification of the process of assembling a radial engine by permitting the construction of sub-assemblies.

Broadly speaking, the present invention contemplates further simplification of radial-engine assembly processes by'ca'lling for a first sub-assembly including an open-ended crankcase with cylinders, pistons, connecting rods, and the central cluster; for a secondsub-assembly'including an end plate to fit' an end of the crankcase and to carry a first crankcase member; and for a third sub-assembly including a second end plate to cover the other end of the crankcase, and to carry bearing means for another crankshaft member! Both crankshaft members'cooperate with themselves and with the cluster to'form in effect a single crankshaft linked to'the' cluster. The three sub-assemblies maybe readily fastened to each other to complete assembly ofsubstantially the entire engine;

In the preferred specific embodiment to be described, the principal power output from the engine is transmitted via the first crankshaft member which includes a crankpin or offset bearing portion slidably receivable in the cluster. The second crankshaft member includes an offset arm which is attached to the offset end of the first crankshaft member after the latter has been inserted in the cluster, that is, after the first and second-mentioned sub-assemblies have been put together. The second crankshaft member includes a main-bearing portion which is slidably receivable in the bearing of the third sub-as sembly, so that the engine is substantially completely assembled When the third sub-assembly is fitted to the first two.

Referring to Figs. 1, 2, and 3 of the drawings, my invention is shown in application to a fivecylinder radial engine having five cylinders Ill integrally formed with a crankcase H. The crankcase II is preferably annular in shape so as to provide relatively wide generally circular openings l2 and 13 at each end. It will be understood that, if desired, the crankcase may be formed as a single annular piece without the cylinders attached, and that the cylinders may be thereafter fitted upon pads suitably machined on the annular crank-case.

The crankcase may be completed by attachment of two end-plate members I l-I5, which close off the openings I2 and [3 in the crankcase and which each support parts forming separate sub-assemblies.

As indicated above, my invention is characterized by essentially three sub-assemblies. The first of these, namely, that built around the crankcase ll, preferably comprises pistons I6 within their respective cylinders It], all pistons l6 being linked by means of suitable connecting rods I 1 to a big-end or cluster l8. If desired, the cluster may be a solid-ring big-end integrally formed with the master connecting rod l9, or it may be pinned thereto as at alternatively, a split big-end construction may be employed. Also, if desired, this first or crankcase assembly may include cylinder heads complete with valverocker arms, and other parts attached to each of the cylinders IB. These latter parts are not shown in the drawings, but it will be clear that they may be part of the first sub-assembly.

A second sub-assembly is preferably built around the end plate I 4. This second sub-assembly is characterized principally by a generally centrally located bearing portion 2| providing main-bearing support for a first crankshaft member 22. The crankshaft member 22 may include offset bearing or crankpin means 23 for slidably fitting within the central bore 24 of the big-end or cluster [8; it may also be formed with a counterweighted portion 25, to permit a balancing of the fully assembled engine. The second sub-assembly preferably is the one through which principal engine output is transmitted; if adapted to the propulsion of an aircraft, the crankshaft may be suitably coupled (by means not shown) to the airscrew or propeller.

A third and last sub-assembly is preferably built around the end plate [5. This third subassembly is also characterized principally by a bearing portion 26 providing main-bearing support for another or second crankshaft member 21. The crankshaft member 27 may include an offset arm 28 for cooperation with the offsetbearing portion 23 of the first crankshaft member 22, as well as a counterweight element 29.

The third sub-assembly preferably supports suitable power take-off mechanisms for valve-timing and for other functions. In the form shown, reduction gears 30, a valve-timing cam 3|, and cam-followers or other actuators (not shown) may all be separately built into this third subassembly.

For the arrangement described, a substantially complete radial'engine may be form-ed by the concurrent or parallel construction of the three sub-assemblies-namely, the central or crankcase assembly, the front-end assembly, and the back-end assembly. Final assembly may be accomplished by slidably introducing the crankpin portion 23 in the center bore 24 of the cluster [8 until the lip or fiange 32 of the end-plate member l4 fits snugly to the crankcase and cylinder sub-assembly, as in the recessed of counterbored portion 33. When these two sub-assemblies have been fitted together in this manner, the crankpin portion 23 preferably extends sufficiently for endwise engagement with the crankarm 28 of the second crank-shaft member 21. After inserting or otherwise associating the crank 28 with the crankpin 23, the third sub-assembly may be fitted to the other or back end of the crankcase sub-assembly, as by homing a flange portion 34 of the end plate I5 within a recessed or counterbored portion 35 on the crankcase ll. Suitable securing means may be provided for positively locking the three sub-assemblies together in the manner described; in the form shown, I employ longitudinally extending bolt means 33 pinning flange 32 into the recess 33, extending across the crankcase through spaces between cylinders, and fastened ultimately in suitable tapped portions 31 in the flange 34 of the end-plate means l5.

Referring now to Figs. 4 and 5, I show a preferred application of the principles discussed general-1y above to a specific radial engine. In Fig. 4 the central sub-assembly (comprising the generally annular crankcase) cylinders, pistons, and linkages have been omitted to illustrate more clearly the arrangement of bearings and the relationship of the crankshaft parts. The arrangement of Fig. 4 is, therefore, only for the purpose of illustrating the cooperation between two of the intended three sub-assemblies. The first of these two sub-assemblies constitutes'the front end of the finished engine and is. built around a frontend plate 38 suitably formed, as with a'circumferentially extending flange 39, for secure and tight-fitting engagement with one side of the central or crankcase assembly. The front plate 38 may support anti-friction bearing means Ail-M for free journalling of the main drive shaft 42, which is shown formed as a part of a first crankshaft member. This first crankshaft member, like the first crankshaft member of Figs. 2 and 3, preferably'inclu-des a'crankpin 43 for slidable engagement with the inner bore of the connecting-rod'cluster (not shown); The first crank-shaft member '42 may also include a counterweight element 44. Preferably, the structural design of the crankpin 43, and of the crank arm 45 which offsets it from the main drive shaft 42, is such as to provide complete or substantially complete cantilevered support for the" entire thrust delivered by the assembled engine.

The, other or back-end sub-assembly is built around a back-end plate member 46, which may also include a circumferentially extending machined portion 41 for close and tight-fitting engagement with the'crankcase assembly. The end plate. 46.. may. include suitable.lcearingv means. 48 for providing main-bearing supportfora second crankshaftmember 49... In: the form shown, this last sub-assembly. ismadeto includethe bearin 48..b.ut notLthe, crankshaft member. 49, the, latter being inserted upon final assembly, as will later be clear. The back-end sub-assembly may also include suitable auxiliary shafting 50 for driving the valve-timing mechanism. In the form shown, valve timing is effected through a reduction-gear train comprising a pinion i keyeqto the shaft 56, a gear 52 supported on an. idler shaft 53 and meshing with the pinion St, a pinion 54 driven by the idler shaft 53, and a gear 55. driven by the pinion 54; the pinionmay be formed with or locked to a. single annular cam. 56. The backend sub-assembly may also carry cam followers 5T for cooperation with the.cam'56 and suitable guide means 58.for supporting the cam. followers 51 or other actuator means for the valve. back-end sub-assembly. is also shown to include-a number of studs 59 to receive other auxiliary attachments for the engine, an annularly extendin inlet-manifold system 66 with outlets 61 to the various cylinders, and suitable lubricating ducts for the main-bearing surfaces.

In the final assembly of an engine according to Fig. 4, the front-end sub-assembly is preferably first fitted to the cylinder-and-crankcase subassembly, as by introducing the crankpin 43 into the big-end cluster (not shown). ,The crankshaft member 49 is then fitted to that part of the crankpin which extends longitudinally beyond the back end of the cluster. In the form shown, this attachment is secured by means of a transverse pin or bolt means 62 carried by the crankshaft member 49 and fitting in a transverse groove which may be milled in the crankpin 43.

The front-end, and crankcase sub-assemblies are then ready for fitting to the third or backend sub-assembly. This fit may be accomplished by slidably introducing the main-bearing portion 63 of the crankshaft member 49 into the inner ring of the bearing 48 and in locking engagement with certain adapter portions of the auxiliary shaft 50. Final assembly may be completed by securing the end plates 38 and 46 to the crankcase as by employment of longitudinally extending bolts (not shown).

In order to maintain positive drive to the auxiliary shaft 56 means may be employed for locking shaft 50 to the crankshaft member 49. In the form shown, such connection is accomplished by providing the drive end of the shaft 56 with a projecting locating pin or stud portion 64 followed by a generally cylindrical portion 65 on which a flat 66 and a fiat 61 have been milled. Preferably, the flats 66 and 61 are at different radial displacements from the axes of the auxiliary shaft 50. The crankshaft member 49 in turn is suitably formed with recesses and counterbored portions to receive parts 64 and 65 of the shaft 56, and it will be clear that the flats 66 and 61 will provide adequate locking. The fact that the flats 66 and 61 are at different displacements from the center of the shafts will clearly prevent any possibility of error or ambiguity in the timed operation of the cam as a result of errors in final assembly.

It will be appreciated that I have provided an improved structure for a radial engine, whereby simplification may be effected in the sub-assembly and in the final assembly of the principal parts.

A number of parts have been eliminated. By

The

6 fabricating the. crankcase. symmetricallyjabcut the plane. of the cylinder axes. it will be clear that machining processes may. be simplified. The arrangement is considered particularly useful from the. view point of .lowrcostmaintenance.

While. I have describedmyinvention in detail for the preferred formshown, itwill be. understood that modificationsjmay. be. madewithin the scope of theclaimswhich follow.

I. claim:

1. Ina crankshaft, a main shaftportionfor principal power output, acrankpinportion including a cranking axis offset from the axis of said main shaft portion, valve-timingmeans, and a. crank portion to engage said crankpin portion and for driving said valve-timing means, said crank portion including a hub. journalled ina subassembly including said valve-timing means, and means within said hub and including axially slidable asymmetrical interlocking means for locking saidv crank portion and said valve-timing means against relative angular movement, said interlocking means being asymmetrically disposed about a normal section, whereby there may be a first subassembly including said valve-timing means and a second subassembly includingsaid crankshaft and whereby said subassemblies may be readily assembled to each other without the possibility of error in the setting of said valvetiming means.

2. In a crankshaft, a power output end, a power take-off end, and an offset crankpin portion therebetween, valve-timing cam means, said power take-01f end and said valve-timing cam means including cooperating axially slidable asymmetrical interlocking means, there being such asymmetry of said axially extending interlocking means that there may be but one relative angular position of engagement of said power take-01f end and said valve-timing cam means, whereby said valve-timing cam means may be separately assembled and adjusted without the need for further adjustment after assembly with said crankshaft, and keying means engaging said power take-01f end and said power-output end against relative angular movement about the crankpin axis, whereby said keying means may positively hold alignment of the main journalled axes of said power-output end and of said power take-off end, and whereby the load on said crankpin portion may be shared by separate end bearings for said power-output end and for said power take-off end.

3. In an engine of the character indicated, a crankcase subassembly including a crankcase open at both axial ends, a cylinder, a piston in said cylinder, and a connecting rod connected to said piston and free in said crankcase; a first end subassembly including a plate for one end of said crankcase, and a crankshaft member journalled in said plate; and a second end subassembly including a housin to cover the other end of said crankcase, a second crankshaft member, and valve-timing means connected to said crankshaft member and self-contained within the axial limits of said housing; one of said crankshaft members including a crankpin to cooperate with said connecting rod upon endwise assembly of one of said end subassemblies with said crankcase subassembly, and the other of said crankshaft members including means asymmetrical about the rotary axis of said crankshaft members and to be driven by said crankpin upon endwise assembly of the other of said end subassemblies 7 with the combinedassembly of said one end subassembly with said crankcase subassembly.

4. In a radial engine of the character indicated, a crankcase subassembly, and two endcover subassemblies, all said subassemblies being Separately assemblable and being thereafter assemblable to each other upon end-wise sliding insertion so as to effectively close the crankcase, a split crankshaft including two parts separately journaled in and forming part of the two of said subassemblies, said two parts including interengaging means asymmetrical about the rotary axis of said crankshaft, one 'of said end-cover subassemblies including a housing and valve-timing means self-contained within the axial limits of said housing and connected to the crankshaft part in said one end-cover subassembly.

5. In a crankshaft, a main shaft portion for principal power output, a crankpin portion including a cranking axis offset from the axis of said main shaft portion, and a crank portion to engage said crankpin portion and including a valve-timing shaft portion and a hub, and asymmetrical locking means on said valve-timing shaft portion, said locking means including two fiat surfaces parallel to the axis of said valvetiming shaft portion but at difierent radial distances therefrom, whereby upon assembly with further valve-timing means adapted to fit said valve-timing shaft portion there may be only one relative angular positioning of said interlocking parts.

' GLENN D. ANGLE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 284,372 Brotherhood Sept. 4, 1883 692,625 Clark Feb. 4, 1902 1,256,833 Scott Feb. 19, 1918 1,447,245 Gore Mar. 6, 1923 1,670,294 Angle May 22, 1928 1,921,985 Moore 1- Aug. 8, 1933 2,271,011 Hubbard Jan. 27, 1942 FOREIGN PATENTS Number Country Date 193,750 reat Britain Mar. 1, 1923

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