Barrel engine connecting rod

A two piece connecting rod assembly for a axial cylinder, internal combustion engine with each rod half having a bearing sleeve at each end for pivotal engagement with the universal joint turnion. The two rods are connected to each other at their centers and spaced apart concentric relations through a pair of raised bosses with mating surfaces and a bolt for retention of the two rod halves as a unified structure.

BACKGROUND OF THE INVENTION 
The present invention relates to internal combustion piston engines and 
more specifically to the universal joint connecting rod of a barrel type 
or axial piston engines wherein the cylinders are arranged around a 
central drive shaft, with the axis of the cylinders lying parallel to the 
drive shaft. 
Many patents on barrel type engines have been granted over the years, 
including applicant's own U.S. Pat. No. 5,094,195. Despite their early 
designs, barrel engines have not had any significant commercial successes. 
Their only commercial success has been in the configuration of hydraulic 
pumps and motors rather than internal combustion engines in the last fifty 
years. There have been military applications as a torpedo engine powered 
by liquid oxygen and hydrocarbon fuels. In aviation, barrel engines have 
particular appeal because of their compact design and reduced frontal 
area, as compared with radial engines or opposed air cooled cylinder 
engines of comparative cylinder displacement. 
In barrel engines, the conversion of reciprocating piston motion to rotary 
drive shaft motion has been accomplished by devices referred to as swash 
plates or wobble plates, as shown in Schramm (U.S. Pat. No. 4,497,284); or 
a cylindrical cam and roller followers, as shown in Sappington (U.S. Pat. 
No. 2,256,952). They have also been referred to as spiders which are 
driven by offset shafts, as shown in applicant's own above-mentioned 
patent. Due to the rotational and wobbling action of the swash plate or 
spider, it is necessary to have universal joints located somewhere between 
the engine pistons and the spider. In applicant's above-mentioned patent, 
this universal joint action was achieved with ball and socket joints which 
are difficult to service and maintain. Furthermore, the construction of a 
ball and socket joint is very difficult to machine while holding 
tolerances and therefore is very costly. 
Various barrel engine designs providing this mechanical connection between 
a reciprocating piston and a wobbling, or rotating swash plate have been 
made, as typified in the above-mentioned patents to Schramm and Sappington 
and to Schlenker (U.S. Pat No. 1,869,440) and Fuhr (U.S. Pat. No. 
1,696,676). In most of the above-mentioned designs, the connecting rod 
between the piston and the spider is a unitary structure such as utilized 
with conventional crankshaft engines. 
SUMMARY OF THE PRESENT INVENTION 
The present invention is directed to a connecting rod assembly which 
includes two connecting rod halves, also referred to as connecting rods, 
joined as a unitary structure upon assembly by an extended boss on each 
connecting rod which has mating surfaces engagable with the boss of the 
opposing rod whereby the alignment of the bearings at opposite ends of 
each connecting rod are maintained in concentric alignment for support and 
engagement of both the spider trunion and the piston trunion. After 
opposing connecting rods have been slid in place over the ends of the 
spider trunion and the piston trunion, they are retained in place by a 
bolt passing through the center of the mating bosses providing a rigid, 
spaced apart connecting rod structure. The lateral tolerance fit between 
the connecting rod halves and trunions is varied by inserting different 
size spacer sleeves between two engaging bosses, one on each opposing 
connecting rod. 
It is therefore the principal object of the present invention to provide a 
simplified connecting rod design which incorporates a pair of opposing 
like rods with unbroken bearings. 
Another object of the present invention is to provide a connecting rod 
assembly with a maximum of bearing area. 
A further object of the present invention is to provide a more simplified 
connecting rod assembly in manufacturing, assembly and service.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
The connecting rod assembly of the present invention is best seen in FIG. 3 
and is generally described by reference numeral 30. The internal 
combustion barrel engine is which the connecting rod assembly 30 is 
located is generally described by reference numeral 10, as seen in FIG. 1, 
and generally includes a stationary cylindrical cylinder block 14 having a 
rotating drive shaft 12 passing therethrough. Driveshaft 12 includes an 
offset end portion 13 which rotatably supports a spider 16 on a pair of 
sleeve bearings 26 and a roller thrust bearing 21. 
While only one cylinder 18 is shown in FIG. 1, the engine 10 can include 5, 
7 or 9 cylinders. Spider 16 includes a ring gear 28 which meshes with ring 
gear 29 on cylinder block 14 as it wobbles. Spider 16 does not rotate. 
The connecting rod assembly 30 of the present invention comprises a pair of 
connecting rods or connecting rod halves 32 and 34, as best seen in FIG. 
3, which engage journals 60 of piston trunion 52 and journals 58 of spider 
trunion 49 and will be later described in detail. Drive shaft 12 rotates 
in cylinder block 14 in a pair of sleeve bearings 24 and is limited from 
axial movement by thrust roller bearing 27 which bears against head 15 
which is only symbolically shown since it is not a part of the present 
invention. 
Both connecting rods 32 and 34 include a pair of unbroken bearings 36 and 
37 at opposite ends of the respective rods. Bearings 36 on each rod 32 and 
34 engage a pair of journals 60 extending outwardly from both sides of 
piston trunion 52 in a sandwiched relationship. Piston trunion 52 includes 
two bushings 62 positioned normal to journals 60, through the center of 
piston trunion 52. Bushings 62, in turn, engage piston pin 64 once 
assembled. Piston pin 64 is held in place in piston 20 by a pair of 
conventional snap rings 66. At the left end of connecting rods 32 and 34, 
as seen in FIG. 3, is a similar bearing 37 in both rods which engages a 
pair of journals 58 extending outwardly from both sides of spider trunion 
49. Spider trunion 49 includes two normally positioned bushings 56 
relative to journals 58 passing completely through trunion 49. Trunion 49 
is in turn rotatably journaled on pin 68 which is anchored to spider 16 
through a pair of bushings 74 located in a pair of ears 57 which are an 
integral part of spider 16. Pin 68 is held in place in spider 16 by a 
concentrically positioned bolt 70 which passes through enlarged retainer 
washers 72 and 76 for engagement with nut 78. Spider trunion 49 includes a 
thrust bearing surface 54 which handles thrust loadings through washer 50 
against the inside surfaces of ears 57 on the spider. On the inside of 
piston skirt 86, as seen in FIG. 3, is a raised thrust surface 61 which 
transmits thrust loading from the piston trunion bearing surface 88 to the 
piston 20. 
FIG. 4 illustrates a modified bearing surface 92 on the piston skirt 86. 
Positioned between surface 92 and the trunion bearing surface 88 is a 
washer 90 which is fully supported by bearing surface 92. 
Located in the approximate center of each piston rod 32 and 34 is a 
outwardly extending boss 40 and 38 respectively as seen in FIG. 3. Boss 38 
includes a cross slot 44 sized to receive a two-sided end post 42 located 
on the opposing connecting rod 32. End post 42 snugly receives mating slot 
44 in the opposing connecting rod half which maintains a concentric 
alignment of the pairs of bearings 37 and 36. The bosses 40 and 38 are not 
centered between bearings 37 and 36 but rather are offset so they cannot 
be wrongly assembled. 
Also positioned between connecting rods 32 and 34 is a spacer sleeve 48 
which is held in place therebetween by bolt 46 which passes through a 
recessed opening 45 and a bolt hole for engagement with a threaded bolt 
opening 47 in opposing connecting rod 32. With the two connecting rod 
halves 32 and 34 fully assembled in sandwiched relation around journals 58 
and 60 and the attachment bolt properly torqued, spacer sleeve 48 provides 
the correct lateral tolerance fit for the opposing pair of bearings 37 and 
36 on their respective trunions 49 and 52. Bolt 46 can utilize various 
well known forms to lock the bolt in place. Sleeve spacer 48 can be 
changed to adjust the tolerance fit of the connecting rod assembly 30. 
Both trunions 49 and 52 basically provide universal joints at the ends of 
pistons rods 32 and 34 due to the normally positioned rotational bushings 
62 and 56 thereby allowing their respective trunion to freely pivot on 
pins 64 and 68 respectively. 
FIG. 2 illustrates an assembled side view of the connecting rod assembly 
assembled on piston 20 for pivotally attached to spider 16. FIG. 2 
illustrates spider 16 with its upper ear 57 broken away to better 
illustrate the assembly. Located between thrust bearing 54 and ears 57 is 
a flat thrust washer 50. 
The double connecting rod design which engage trunion journals 58 and 60 in 
a sandwiched relationship allows the use of solid bearings 36 and 37 in 
place of conventional bolt-on split bearings which are most commonly used 
in piston engines. This pair of connecting rods 32 and 34 with solid 
bearings surrounding and retaining journals 58 and 60 provide in a very 
simple, high strength connecting rod design for a piston engine with a 
minimal amount of rod bolts as compared with conventional designs.