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Патент USA US2404032

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July 16, ‘1946.
G. E. BURKS
- 2,404,032
VALVE TAPPET- MOUNTING
Filed July 9, 1945
5 Sheets-Sheet 1
G- .
,HIWmHI:
IN VEN TOR.
George E. Burks
BY - aw?y. 72W
ATTORNEY.
July 16, 1946.
‘ s. E. BURKS
2,404,032
‘VALVE TAPPET -MOUNTING
Filed July 9, 1945
3 Sheets-Sheet 2
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George E. Bur-ks
ATTTORAE)’.
‘ July 16, 1946.
2,404,032
' a. E. BURKS
VALVE TAPPET mopn'rme
Filed July 9, 1945
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‘INVENTOR.
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' George E. Burks
a/MZI-W'
‘
ATTORNEY.
02,404,032
Patented July 16, 1946
UNITED STATES PATENT OFFICE
2,404,032
VALVE TAPPET MOUNTING
George E. Burks, Peoria, 111., assignor to Cater
pillar Tractor 00., San Leandro, Calif., a cor
poration of California
,
Application July 9, 1945, Serial No. 603,799
'1 Claims.
(Cl. 123--90)
1
2
jects and advantages of the invention are made
The present invention relates to the mounting
of valve tappets or guides for valve tappets which
apparent in the following speci?cation wherein
reference is made to the accompanying drawings
are employed as a part of the valve operating
, which illustrate a preferred form of the inven
mechanism of an internal combustion engine.
tion applied to an ‘internal combustion engine
6
Conventional types of internal combustion en
of conventional design.
gines comprise cylinders usually disposed vertical
In the drawings:
ly in a cylinder block. Valves which control the
Fig. 1 is a. diagrammatic view in side elevation
intake of air and the exhaust of residual prod
of an internal combustion engine with portions
ucts of combustion from the cylinders are actu
broken away and illustrated in section to show
ated by mechanism which include push rods and
the application thereto of valve tappet mount;
tappets arranged vertically adjacent the cylinder
ings embodying the present‘ invention;
block. The lower ends of the tappets are en
gaged by cams on the cam shaft disposed longi~
Fig. 2 is a. front elevation of the engine shown
in Fig. 1 with a portion illustrated in section to
tudinally of the block and driven in timed rela
disclose details of construction of the invention:
‘ Fig. 3 is an enlarged fragmentary sectional
tion to the reciprocal action of the pistons in 15
the cylinders. It is desirable that the cams en
gage squarely against the lower ends of the tap- \
pets as the timing and distance of opening of '
the valves are critical factors in perfect engine
performance. If the tappet guides are misaligned, 20
the tappets do not seat squarely against the cams
Fig. 4 is a sectional‘ view taken on the line
IV——IV of Fig. 3; and ‘
but may ride on one edge of the cam face. As
a result of such operation, excessive wear takes
mechanism in a typicalinternal combustion en
gine is illustrated in Figs. 1 and 2 wherein the
place between the cam and shaft which affects
the timing and opening of the valves. The tap
pet guide also becomes worn because of such
misalignment and various other undesirable re
sults occur.
view taken on the line III-—III of Fig. 2;
Fig. 5 is a sectional view taken on the line
V-V of Fig. 3.
,
The general arrangement of valve operating
engine is illustrated at I0. Conventional cylin
ders, shown in dotted lines at Ii in Fig. 2, are
disposed within the engine block and pistons l2
reciprocate in the cylinders and impart rotation
to a crank shaft I! by means of connecting rods
H. The upper ends of the cylinders are provided
with intake and exhaust valves such as indicated
at i5 and these valves have stems l6 engaged by
rocker arms ll which are pivotally mounted as
~
It has been common practice to mount valve
tappet guides against the side of the engine block
on a ?at surface and to secure them in place by
cap screws. This ‘practice required many ma
chining operations, such as the production of a
?at surface on the block and on the bracket, bor
at l8. ‘Springs, not shown, normally hold the
valves IS in closed positions andthey are opened
ing the tappet guide through the brackets and 35 in timed succession, and in proper relation to the
providing for the cap screws which extended
reciprocal action of the pistons in the cylinders,
through the 'bracket and into the block. Each
by means of pusher rods 19 disposed on the out
of these operations had to be separately‘ per
side-of the _-cylinder"iblock and engaging at their
formed with no particular relation to the others
upper ends‘ with ,ithe rocker arms l1 and at their
40
or to the line of the cam shaft bearings in 'the
lower‘endsl‘with'tappets 20. The tappets 20 are
block. Even allowing a minimum'tolerance prac-,
mounted for. reciprocation in guides 2i and have
tical for machining operationsjof this kind, slight
lower . fe'nds projecting downwardly from said
errors in each operation would sometimes accu
mulate to produce a substantial misalignment.
_
It is‘ an object of the present invention to'over-.
come the disadvantages herein referred to and
to provide a mounting for valve tappets which
insures perfect alignment of the tappets with
. desand engageable with cams 22 on a cam
45
shaft '23. The cam shaft 23 is journaled for-“r0
' tation in spaced bearings 24 which, as illustrated
in Fig. l,.are cast as integral parts of the engine
block.
The cam shaft is connected with the
crank shaft I3 for rotation thereby by means ‘of a
relation to the cam shaft of the engine upon
train of gears, not shown, in accordance with
50
which they are mounted. A further object of
conventional practice. By reason of this con
the invention is to provide a means for mount
nectlon. the cam ‘shaft is rotated in timed rela
ing valve tappets which requires a. minimum of
tion to the crank shaft and to the, reciprocal
' simple machining operations capable of being
action of the pistons which drive the crank shaft.
performed in a manner greatly to reduce the‘pos
The arrangement of the individual cams'22 on
sibilities of error: Further and more specific ob- 55
2,404,032 '
J the cam shaft is such that during each rotation
of the shaft, each one of the intake and exhaust
valves II is opened in properly timed relationship
to the operation of its respective piston,
The engine illustrated in Fig. l is of the six
cylinder type and each cylinder has an associated
pair of valves, push rods l9, tappets 29 and tap
pet guides 2|. The pairs of tappet guides 2| are
illustrated herein as connected in groups of three
plementary seating surfaces 21 on the casting
are true with relation to the vertical bores in
the tappet guides 2|, the lower ends of the tap
pets must rest squarely on the surfaces of the
cams 22. The semi-cylindrical surfaces 21 on
the casting which includes the tappet guides 2|
are somewhat larger than the rest of the casting
and are spaced between the longer portions which
pairs each so that two such groups are employed 10 form the guides 2|. Hence, the entire casting
may be supported between centers on a lathe
to accommodate six cylinders. It is, of course, to
- be understood that the invention herein de
' scribed is applicable to engines having any num
or similar machine for formation of true sur
faces on the members 21 and the same centers
established at the ends of the casting for form
ber of cylinders and that the grouping of the
tappet guides may be varied from the arrange 15 ing these surfaces may be used in aligning the
work for boring out the guides 2| for reception
ment herein illustrated.
‘
In‘ conventional construction, the tappet guides
2| have been formed as a part of a casting having
a ?at surface which flat surface is bolted ?ush
against a ?at-surface on the engine block for
support. Such construction has been conducive
to ‘misalignment of the guides through error vin
laying out and machining operations so that in
some cases the lower ends of the tappets have not
of the reciprocal tappets 20. Consequently, the
bores of the tappet guides can readily be formed
normal to the longitudinal axis about which the
surfaces 27 are turned and as the seats 2| in the
engine block which receive the surfaces 21 are
formed parallel to the cam shaft bearings, a
perfect seating of the tappets against the sur
faces of the cams on the cam shaft is assured.
. rested squarely» on the surfaces of the cams 22 25 The alignment of the tapped holes for the cap
screws 29 is easily accomplished and does not
but rather have been anguiarly disposed so that
they engaged one edge only of the cams with the
result that excessive wear and imperfect engine
affect the position of the bracket which the cap
screws support.
a
I claim:
1. A device for mounting valve tappets or the
According to the present invention, the tap 30
like on the side of an engine block which com
Det guides 2| are formed as a part of a casting
prises a casting having portions of cylindrical
or ‘castings which are secured to the engine
contour formed thereon and adapted to be re
block in a manner which practically elimi
operation follows.
.
ceived in recesses of complementary contour in
nates possibility of their misalignment. For
example, ‘as shown in Figs. 1 and 3, the tappet 35 the block.
2.
A
device
for
mounting
valve tappets or the
guides 2| areformed in groups of three pairs
like on the side’ of an engine block comprising
integrally cast and connected‘ by semi-cylindrical
a casting having tappet guides bored therein,
connecting members 25 which have centrally dis
semi-cylindrical seat portions on the casting
- posed reinforcing ribs 28. The exact shape of
the connecting members 28 and ribs 26 is subject 40 formed about an axis at right angles to the axes
of said tappet guides and adapted to seat in re
to variation and is not an essential characteristic
cesses of complementary contour in the block.
of the mounting structure so long as it forms a
3. Adevice for mounting valve tappets on an
rigid connection between the pairs of guides 2|.
engine block for engagement with spaced cams
Between the guides 2| of each pair a similar but
on an engine cam shaft which comprises, a brack
shorter connecting shape is employed and is
et, tappet guides bored in the bracket, and 9. cy
provided with an enlarged semi-cylindrical por
lindrical surface on the bracket formed on an
tion 21, see also Figs. 4 and 5, capable of being
axis at right angles to the axes of said tappet
' machined to present a perfect semi-cylindrical
guides, whereby the cylindrical surface will seat
contour. This surface 21 is adapted to be dis
in a cylindrical recess bored in the block parallel
posed against a registering semi-cylindrical sur
face 28 ‘machined on the side of the engine block, 50 to the cam shaft to position the tappets at right
angles to the cam shaft.
‘
as best illustrated in Fig. 2, where the block is
4. A device for mounting valve tappets on an
shown as cast to a shape providing surfaces for
engine block for engagement with spaced cams
such machining. Cap screws 29 are employed to
on an engine cam shaft which comprises, a brack
secure the castings against the side of the block
with the semi-cylindrical machined surfaces 21 55 et, tappet guides bored in the bracket, and a '
seating against the complementary concave sur
cylindrical surfac on the bracketformed on an
axis at right angles to the axes of said tappet
faces 28 formed in the side of the block. With
this construction a relatively small number of
cap screws is needed as the complementary semi
guides, whereby the cylindrical surface will seat
in a cylindrical recess bored in the block parallel ,
cylindrical surfaces provide an accurate seat 00 to-the cam shaft to position the tappets at right
which holds the casting in alignment and the cap
angles to the cam shaft and means to secure
the bracket against the engine block.
screws are necessary only to prevent the casting
from moving away from the block.
5. A device for mounting valve taDDets on an
The construction herein described lends itself
engine block comprising, a plurality of tappet
65
to simple and easily performed machining oper
guides formed integrally with connecting and
ations which insure accuracy in the alignment
supporting members, and a plurality of aligned
of the tappet guides. For example, the semi
conve'x seating portions on said connecting and
supporting members adapted to register with
cylindrical concave seats 28 in the side of the
complementary concave seats formed on the en
block may be bored at the same time that the
block is set up for machining the crank shaft 70 gine block.
6. A device for mounting valve tappets onan
bearing brackets and the bearings 24 for the ion
engine block comprising, a plurality of tappet ..
gitudinally extending cam shaft 23. This in
guides formed integrally with‘ connecting and
sures~thatfall offfthe‘ seats 28 will be perfectly _ supporting
members, and a plurality of aligned ‘
aligned with the‘ crank's'hsit so that if the com~ 75
convex seating portions on said connecting and
zgoeose
-
supporting members adapted to register with
'
e
nesting members, aligned convex seating portions
complementary concave seats formed on the‘ en
on said connecting members having semi~cy1in
gine blockseid seating portions being positioned
dricalosurfaces formed on a common center line
between tappet guides. V
and adapted to register with complementary
7. A device for mounting valve tappets on an 5 concave seats formed in the engine block.
engine block comprising a casting including .por
tions for tappet guides and intermediate con
GEORGE E. BURKS.
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