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Патент USA US2108514

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Feb.` l5, 193:8.
C. E. suMMERs
Filed Aug.V 1_6, 1955
2,108,514 l
' Patented Feb. 15, ,21938
u_NiTED STATES rATEn-r‘ otr-i
Caleb E. Summers, Pontiac, Mich., assignor to~ General Motors Corporation,- Detroit, Mich., a
corporation ot’ Delaware
Application August 16, 1935, Serial `lzl'o. 36,465 »
(ci. 12s-_9m
lventional automobile engine provided with cam-4
-.This invention has' to do with. hydraulic take
||l having cam I2 thereon adapted to pe- f
up mechanism especially adapted for use in the _ shaft
riodically lift the'` tapp'et designated I4 in its
valvemechanism of internal combustion engines.
entirety. >The tappet comprises telescoping thrust
In theñ form illustrated the take-up mechanism
devices one of whichV consists of the cup I6, 5
- 5 is embodied in a valve tappet of the type usually
`and the other consists
of thrust member I8,
interposed between the camshaft and the valve . together with thepi'ston I9
to which it is loosely
stem or push rod and adapted to transmit the
connected. To accomplish this the piston I9
valve operating thrust of the cam.
is preferably apertured at 20 to loosely receive .
The improved take-up mechanism consists es
lower reduced portion 2| of the thrust mem- 10
10 sentially of _a plurality of telescoping thrust de
ber I8 and sleeve '21| is a press-fit upon the ex
- vices,I one of which is preferably in the form of
tension 2|. The sleeve `24 is provided at its
4a cup,~ while the other comprises a piston slid
ably mounted in the cup and loosely connectedV - ' upper end with an outturned flange 26 formed
to a thrust transmitting member which serves with radial grooves 21 asbest shown in Figure 3
15 to control the ñow of ñuid into and out ofthe which provides passages communicating with the 1_5 ‘
hydraulic chamber formed between the piston clearance about the member I8. The space be
'and the bottom of the cup. -Means isprovided tween the «upper surface of the- flange 26 and
the shoulder 28 formed at the junction of the
to yieldingly urge the thru‘st-transmittingmem
portion 2| with the main portion of the
ber in a direction to permit i'low, but,upon ap-f» reduced
thrust member- I8 is slightly greater than the- 20
.2d plication of thrust to the valve operating sys
tem the flow is shut off and the ñuid inthe thickness of the end wall of piston I9, thereby
permitting a slight relative movement between»
' chamber acts' as a Iixed abutment -during the
the thrust member Vand piston. The opposed
.balanceof the valve operating cycle.
When the' valve operating pressure is removed l surfaces of the shoulder 28 and the piston when
_from the system the thrust-transmitting mem
ber is moved to a position to permit flow’ofiiuid
brought into contact> with eachother seal the 25
length of the train of mechanism due 'to ex
pansionand contraction of the -parts or~ other
In the bottom of the cup is located the springi- 1
30 which` reacts against the iiange 26 -so as to 30
passages from the hydraulic lchamber ¿consti
Ainto and out of the bottom of the hydraulic ,f tuted by the grooves V21 and the clearance between '
chamber to compensate 'for` variations in the the extension 2| andthe aperture -in the piston. è _
urge the thrust member upwardly to take up4
lash and at the same time tend to separate the
The principal advantages of the invention sealing»
surfaces at the shoulder'28 to permit are the controllable lash and positive action ofÀ
the means controlling ñow of fluid into and outa
of the hydraulic chamber. It has been unde
sîrable to have tappets-which take-up to no lash
since a slight eccentricity of the base circles
of the cam tends to makethe valve ride, 'thereby
lessening its pressure on its seat-,.interferingwith
fluid to enter or leave'the hydraulic chamber
'to compensate for variations in lash due to ex- 35
pansion or contraction of the parts of the valve
, mechanism.
`32 indicates a tubularguide lmember which
may b_e formed of sheet metal, and is preferably
a press- ñt withinthe upper portion .of 'the cup, 40
46 heat flowand putting extra duty -and harder' the
lower portion of the enlarged portion 34 of
wearïon the tappet. The improved construction
-is also characterized by- absence of‘ ball check
4valves, or the like, which operate with very light
Ipressure, and are objectionable since the slight
l '45 est ‘obstruction holds them off their seat.
Other objects and advantages of the inven
tion will be apparent in the `course oi the follow
ingîdescription in whichz'
Figure 1 is a sectional View through a portion
50' of 'an automobile engine showing the construc
and location`
2 is 'an of
the device.l
View of a
portion of the device. -
Figure 3 is a~ section on lin'e 3_3 of Figure 2.
In Figure 1 there is shown a portion of a con-J-N
the guide resting on shoulder 36, provided in
the cup member I6.
While the upper portion of the thrust- member
|8,could, if desired, be shaped to directly engage- 45
the valve stem, I have preferred to employ an
adapter 3,8 which is seatedon the member I8. ^
` At 40 is shown the valve with which the adapt
er 38 is inoperative engagement, and 42 indi
cates the spring normally urging the valve on its 50
seat. In order to insure a supply of oil to theA
tappet. the cup I6 -is preferably apertured at 44,
and oil is supplied to the tappet through passage '
46 which is preferably `at all times in communi- '
cation with a. reduced annular» portion I8 of the 55
tappet, as shown. In the construction of the
device the fit of the piston I9 in the' cup I6 will .will'be apparent that it is of utility Wherever a
hydraulic take-up device may be found desirable.
be held to close tolerances.` With the passage
to the hydraulic chamber open the space be
tween the shoulder 28 and the top of the piston
should preferably be rather slight, for instance,
on the order> of'.005".
1. In hydraulic take-up means the combina
tion of telescoping thrust devices, one of said de
vices being adapted to rest on a, body of fluid con
tained in the other, and valve means associated
The device operates as follows: When the
tappet reaches the base circle on the cam, th'e
with said last-named device for» controlling the
10 spring 3II_ urges the thrust member I8 and' adapt-.
er 38 upwardly into engagement with the end of
the valve stem 40. Under these conditions the
passage leading to the hydraulic chamber be
neath the piston will be open, as illustrated.
passage of iiuid to _and from said body and in
cluding a member having a portion exposed out
side of said telescoping thrust membersso as to
receive thrust and transmit it to one of said
members and yielding meansnormally urging
said valve means toward open position.
When the cam starts its _lifting movement, cup
2. An hydraulic valve tappet comprising a cup,
I4 is raised and with it the piston I9, while the
thrustmembe’r I8 and its associate parts are held an apertured piston slidably mounted in_ïthe cup,
against upward movement by the action of the a thrust member passing loosely through the
aperture in the piston, means loosely connecting
valve spring 42. As a consequence the flow of '
the thrust member and piston and adapted to
20 oil from the hydraulic chamber is shut off by en
gagement of thesurfalces- at 28 and from then on permit limited relative movement therebetween, 20
means yieldingly urging the thrust member out
throughout the valve opening-and closing move
of the cup, and cooperating sealing surfaces on
ment the oil in the chamber acts as a solid abut
thrust member and piston brought into play
ment to transmit thrust. When the valve
25 reaches its seat and the system is _relieved of the upon inward movement of the thrust member
pressure of the valve spring 42, spring 30 comes for- sealing the passage between the piston and 25
into play and4 urges the cup` I6 downwardly thrust member constituted by the loose ñt of the
against the base circle of the calm and at the thrust member, in the aperture in the piston.
3. In Vhydraulic take-up mechanism the com
same time urges the thrust member I8 and its
bination 'of a cup, a piston slidable in the cup,
associated parts upwardly into engagement with said
piston being provided with a passage adapted
the >end of the valve stem, thereby opening the
passage beneath shoulder 28', so that if there has to permit ñ'ow of fluid from one side of the piston
been slight leakage or other cause for adjustment p to the other, thrust transmitting means arranged
as, for example, contraction of the parts owing in series thrust transmitting relation with said
35 to cooling, the increased volume of the hydraulic cup and vpiston and loosely connected to the pis
chamber due to the greater separation of- the` _ ton so as to permit relative movement of said
piston I9 and the cup I6_ causes oil'to be drawn means and piston, valve means actuated by rela
tive‘movement of the piston and thrust trans
into the hydraulic chamber.
mitting means for closing said passage, and
An advantage of the -construction _resides in means
yieldingly urging said thrust transmitting
the fact. that the lash in the valve operating
a direction to open said valve means. ‘ 40
system may be made whatever value -is desired
4. In hydraulic take~up mechanism the com
. by adjusting the distance between the upper sur
bination of a cup, a piston member slidable in the
face of ilang‘e 2i and the shoulder 28.
said piston member having a bore therein,
It will be understood that the described actionA
takes place during each operation of the, valve 'a` thrust transmitting member arranged in series
gear, and that the tappet operates as a positive thrust-transmitting relation with said cup and 45,
pump to draw oil into the hydraulic chamber piston and extending through said bore and
each time the valve seats independently of any ` fitting loosely therein so as to permit passage of
pressure from the oiling system, then as soon as
50 the cam. starts to lift the tappet the valve at 28
is closed with all the force of the main valve
» spring 42.
The reservoir inside the cup I6 and below the
openings 44 ,is suiiicient to supply immediately
55 the oil required to put all tappets in perfect ad~
justment when the engine is started up aftera
1ong` period of idleness even though the thrust
members I8 under pressure of the valve spring
have naturally settled down so that the reduced
portions 2l rest onthe bottoms of the tappets.
The >provision for such- engagement provides a
safety factor to permit operation oi’> the engine
even though the tappets should in some manner
become empty of oil.
Since the hydraulic chamber is vented vupon
each operation,.opportunity is presented for the
escape of air should` any be present. However,
the sliding ñt between the cup I6 and its guide
and between the enlarged portion of thrust mem
70 ber III> and its guide provide for escape of air in
the reservoir above the piston so that there is
fluid therearound, one of said members having
abutments thereon adapted to engage the other,
said abutments being- spaced apart to permit
limited' independent movement of said members
inthe line of thrust. one of said abutments and
the other, of said members being provided with
mating surfaces adapted to engage >to prevent
passage of fluid through said bore, and means 55
for yieldingly urging one of said members in a
direction to- hold said surfaces out of sealing
5` In hydraulic take-up mechanism the com
bination' of a cup, a piston slidable inthe cup,
said piston having a bore therein, a thrust trans
mitting member extending through said bore and
having a loose 4lateral llt therein to permit pas
sage of fluid through said bore around said thrust
member, means limiting the endwise movement
of said thrust member with respect to said piston,
said piston and member being provided with co
operating valve means Gadapted to be closed by
inward movement of the thrust member rela
tive to the piston or by outward movement of the 70
piston relative to the thrust member, and means.
little likelihood of air entering the hydraulic , for
yieldingly urging the thrust member out of
the cup.
While the invention is described in connection
l 6. In hydraulic take-up mechanism the com
75 with a tappet for internal combustion engines it
bination of a cup, a piston slidable in the cup,
2,108,514 _
said piston having a bore therein, a thrust trans
mitting member extending through said bore and
having a loose lateral ñt therein to permit pas
sage of fluid through said bore around said thrust
member, means limiting the endwise movement
of said thrust member with respect to said pis
t0n, said piston and member being provided with
cooperating valve means adapted to be closed by
inward movement of the thrust member relative
to the piston or by outward movement of the
piston relative toI the thrust member, means for
yieldingly urging the thrust member out of the
cup, said cup being provided with guiding meansv
for said thrust member.
7. 'I'he combination of-an operating member,
operating the valves of internal c_ombustion en
gines and the like, the combination of an operat
ing member, an operated member, and means for
transmitting thrust from the operating member
to the operated member comprising telescoping
thrust devices, one of said devices being adapted
to rest' on a body of fluid contained in the other,
and valve means controlling the passage of fluid
to and from said body and including a relatively y
movable valve member interposed between said
an operated 'ï member, means for transmitting
ñuid supported thrust device and one of said
members so as to transmit thrust therebetween.
‘t 9. In hydraulic take-up mechanism for use in
operating the Valves of internal combustion en
gines and the like, the combination of an oper
ating member, an operated member, means for
motion from said operating member to said
operated member comprising a plurality of thrust
elements interposed between said members, a
transmitting thrust from the operating'member‘
to the operated member comprising telescoping
thrust devices, one of said devices being adapted
body of viiuid confined between lsaid elements,
to rest on a body of fluid contained in the other, 20
and valve means controlling the passage of fluid
valve means associated with one of said elements
adapted to control ñow of ñuid to and from said
to and from said body and including a member
interposed between said piston and one of said
transmit thrust from one of said members to said ‘members so as to transmit thrust therebetween,
25 element, and means for yieldingly urging said and means normally urging said. valve means 25
Abody comprising a valve member arranged to
' valve member toward open position.
8. In hydraulic take-upmechanism for use in
‘ toward open position.
CALEB E. sum/mas.
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