close

Вход

Забыли?

вход по аккаунту

?

код для вставки
Jan. 7',' 1947. '
J. A. FORBES
- 2,413,818
TRACTOR-TRAILER BRAKE SYSTEM
Filed Feb. 21, 1944
ZSheets-She?v 1
JOSEPH INVENTOR.
A.FORBES
BY,
‘
,1
W1
ATTORNEYS
Jan. 7,1947.
‘.1. A. FORBES
‘ ,
>
2,413,813
TRACTOR-TRAILER BRAKE SYSTEM
Filed Feb. 21, 1.944
2 Sheets-Sheet 2
37
as
_ //
/ -
/
_
‘f
K
_
J\\
\
38 46 45
\
I
I
.
43
\
'
—
%\ ‘\‘m
INVENTOR.
-
JOSEPH A. FORBES
ATTORNEYS
2,413,818
Patented Jan. 7, 1947
UNITED STATES PATENT OFFICE
2,413,818
TRACTGRV-TRAJLER BRAKE SYSTEM
Joseph A. Forbes, Detroit, Mich, assignor to
Kelsey-Hayes Wheel Company, Detroit, Mich,
a corporation of Delaware
Application February 21, 1944, Serial No. 523,275
5 Claims. (Cl. 188—3)
1
2
The invention relates to tractor-trailer brake
systems and refers more particularly to brake sys
tems in which the brake mechanisms of the trac
tor and trailer are applied by mediums separate
The trailer is also of conventional design and
may be four-wheeled or two-wheeled and is
or distinct from each other.
The invention has for one of its objects to pro
with a conventional brake mechanism comprising
the brakes 9 which, as shown, are constructed in
adapted to be mechanically coupled to the tractor
in any usual manner.
The trailer is equipped
the same manner as the brakes I of the tractor
vide an improved tractor-trailer brake system in
with the exception that the wheel cylinders are
which the medium for applying the trailer brake
larger than the wheel cylinders of the tractor
mechanism is under the control of the operator
The braking ?uid for operating the
10 brakes.
of the tractor.
brakes 9 in the present instance is compressed
The invention has for other objects to provide
air having a pressure lower than that created by
an improved tractor-trailer brake system in
the master cylinder in applying the tractor
which the braking effort exerted by the trailer
brakes. The compressed air is supplied by the
brake mechanism is proportional to the braking
tank i0 mounted on the tractor and preferably
effort exerted by the tractor brake mechanism;
connected to the compressor H which is also
and to provide an improved tractor-trailer brake
mounted on the tractor.
system in which the force of the medium for ap
To control the operation of the trailer brakes
plying the trailer brake mechanism is in balance
9, I have provided the control device 12 which is
with the force of the medium for applying the
20 mounted on the tractor. This control device is
tractor brake mechanism.
connected to the master cylinder 3 through the
The invention has for a further object to pro
tubing 1 and the tube is and is also connected
vide an improved device for controlling the me
to the air tank I t by the tube M and to the wheel
dium for applying the trailer brake mechanism.
cylinders of the trailer brakes by the tubing 55
With these and other objects in view, the in
vention resides in the novel features of construc 25 forming the air line. The tubing iii includes the
?exible length It’ permitting relative movement
tion and combinations and arrangements of parts
of the tractor and trailer.
as more fully hereinafter set forth.
As illustrated in Figure 2, the control device
In the drawings
comprises a housing member having the cylinder
Figure 1 is a diagrammatic view of a tractor
[6, the second cylinder H and the valve housing
trailer brake system embodying the invention;
18. The second cylinder I‘! has an internal di
Figure 2 is a sectional View;
ameter smaller than that of the cylinder 56 and
Figure 3 is a view similar to Figure 2 showing
is ?xedly secured in one end of the cylinder i6
a modi?ed construction.
‘preferably by being threaded thereinto. The con
The invention is particularly applicable to trac~
tor-trailer brake systems in which the tractor is 35 trol device also comprises the piston member is
slidable Within the cylinders l6 and I’! and the
a commercial truck of conventional design
valve 2t slida-ble within the valve housing IS.
equipped with a conventional brake mechanism
The second cylinder I‘! is provided with the inlet
comprising the brakes I which may be applied by
2| Which is connected to and communicates with
di?erent mediums, such as ?uid, electricity, or
mechanical linkage. In the present instance each 40 the tube It. The piston member l9 has the larger
and smaller pistons 22 and 23 which are slidable
brake is hydraulically applied and comprises the
in the cylinders 16 and 11, respectively, and are
brake drum 2 mounted on and secured to a tractor
provided at their pressure ends with the sealing
wheel, the internal brake shoes 3 mounted on
cups 24 and 25, respectively. In the present in
the backing plate, and. the Wheel cyhnder 4 also
mounted on the backing plate and having the 45 stance the pistons are integral. The valve hous
ing I8 is provided at opposite sides with the trans
piston rods 5 engageable with the separable ends
verse axially aligned inlet and outlet 25 and 21,
of the brake shoes to separate the same to there
respectively, the former being connected to and
by force the brake shoes against the brake drum
communicating with the tube M and the latter
when the wheel cylinder is subjected to braking
suitably
liquid under
connected
pressure.
to the
Each
master
wheel
cylinder
cylinder
6 by
suitable tubing 1 forming the hydraulic line. The
master cylinder is operable by the brake pedal 8.
The wheel cylinders and the master cylinder are
of conventional designs.
7
50 being connected to and communicating with the
tubing It. The valve housing is provided with
the bore 28 in which the valve 2&3 is slidable and
this bore is axially aligned with the cylinders 56
and 11 so that the valve is in axial alignment
with the piston member [9. The bore 28 is closed
2,413,818
3
4
by suitable means, such as the cap 29. The valve
29 is connected to the piston member l9 to move
in unison therewith by means of the rod 39. The
valve is provided with the annular groove 36
piston 23. As a result, a balance in total pres
sures may be secured. It is apparent that the
which is adapted to register with the inlet 26 and
the outlet H to permit the flow of compressed air
therethrough to the trailer brakes 9 when the
greater the pressure of the braking liquid on the
smaller piston 23 the greater the pressure of the
compressed air on the larger piston 22 to secure
balanced relation.
Upon release of the brake
pedal the parts are returned to their normal posi
tions, at which time the port 34 is open so that
valve is advanced by means of the piston member
the wheel cylinders of the trailer brakes are
19 under the pressure of the braking liquid in the
hydraulic line of the tractor while the tractor 10 relieved from the air pressure.
Figure 3 illustrates a modi?ed construction of
brakes l are being applied. To resiliently hold
control device having a housing member com
the valve 29 in its normal position, at which time
prising the cylinder 36 and the second cylinder
the annular groove of the valve is not in regis
3i‘ of greater internal diameter than that of the
tration with the inlet and outlet of the valve
cylinder
The control device also comprises
housing, I have provided the coil spring 32 which
a piston member comprising the smaller and
is located within the bore 23 and abuts the cal)
larger pistons 38 and 39 slidable respectively in
29 and the valve 29.
the cylinders 39 and 31, and the valve 40. The
To make the braking eliort exerted by the
cylinders are in axial alignment as are also the
trailer brakes proportional to the braking effort
pistons. The cylinder 36 has at one end the
exerted by the tractor brakes i and to balance
inlet éil which is connected to the hydraulic line
the
for force
applying
or the
the pressure
trailer brakes
of the with
compressed
the force
of the tractor and has at the other end the trans
verse air inlet 42 which is connected to the
or the pressure of the braking liquid under pr s
compressed air tank. The cylinder 31 is closed
sure, the vaive housing i8 is provided with the
passageway 33 which leads from the outlet 2? 25 by the cap it which is provided with the air outlet
at which is connected to the wheel cylinders of
to the cylinder In in advance of the larger piston
the trailer brakes. The valve 40 is in axial
22 and the sealing cup 2-4.. By reason of this pas
alignment with the pistons 38 and 39 and is lo
sageway, the pressure of the compressed air in
the outlet 21' and in the tubing is and. the wheel
cated therebetween so that in thenormal or o?
position of the piston member the valve closes
.- -inders of the trailer brakes, which is the same, the air inlet £32. The valve is provided with the
is transmitted to the piston member 59 in oppo
longitudinally extending passageways 45 which
sition to the pressure of the braking liquid used
extend through the larger piston 39 and open
in advancing the piston. As a result, a balance
in pressures of the compressed air and braking
into the cylinder 3? in advance of the sealing
cup for the larger piston. To provide for the
liquid at the ends of the piston member is se
escape of compressed air from the wheel cyl
cured, it being apparent that as soon. as the total
pressure of
coil spring 32 and the compressed‘
inders of the trailer brakes, the cylinder 35 is
air on the larger piston 22 becomes greater than
provided with the transverse port 46 which is
the total pressure of the braking liquid on the
located in advance of the reduced piston portion
33 when in its normal or off position. This port
smaller piston 23, the valve 2:: will be moved
back or retracted by the piston member 59 to
is also located to clear the valve 40.
In operation, it will be seen that when the
communication between the inlet 2E;- and the
0 .let 2?. The displacement of the braking liquid
operator depresses the brake pedal of the tractor
at this time causes a movement of the brake pedal
the tractor brakes will be applied and the brak
ing liquid under pressure will advance the piston
against the operator’s foot, but this movement is
member comprising the smaller and larger pis
very small and hardly noticeable.
To provide for the escape of the compressed air
tons 33 and 39 and during the advance the valve
from the wheel cylinders of the trailer brakes,
(ill will gradually uncover the air inlet 42 to allow
the cylinder is is provided with the transverse
air to pass to the wheel cylinders of the trailer
port
which is open to the atmosphere and
r brakes, the port 46 being closed prior to the
located~ in advance of the sealing cup 24! when
partial opening of the air inlet. The pressure of
the piston member id is in its retracted or normal
the air operating the wheel cylinders of the trailer
position. To provide for free flow of air in the
brakes and of the air in the cylinder 31 is the
space between the larger piston 22 and the second
same and this pressure is transmitted to the larger
cylinder ii, the cylinder !5 is provided with the
piston 39 in a direction opposite to that of the
transverse port 35 which is also open to the
braking liquid on the smaller piston 38 with the
atmosphere.
result that the two pressures will become balanced
In operation when the operator desires to apply
in the same manner as in the device of Figure 3.
the tractor and trailer brakes, he presses down
What I claim as my invention is:
upon the brake pedal 8 and thereby operates the
1. A control device in a tractor~trailer brake
master cylinder 6 to force braking liquid under
system of the type wherein the tractor is equipped
pressure through the hydraulic line ‘i to the
wheel cylinders 4! of the tractor brakes i. At
the same time the braking liquid under pressure
is forced through the tube i3 and the inlet 2|
to the second cylinder l'‘! to advance the piston
member l9 and the valve 2!). During the advance
the annular groove 3! of the valve gradually
comes into registration with the inlet port 26 and
the outlet port 2‘! to allow compressed air to
pass through the tube IE to the wheel cylinders
of the trailer brakes 9. At this time, the port 34
is closed so that compressed air in the outlet 21
reacts on the larger piston 22 in a direction oppo
site to that of the braking liquid on the smaller 75
with a brake and a master cylinder for applying
said brake and wherein the trailer is equipped
with a brake operable by air under pressure, said
device comprising a housing member having a
cylinder connected to said master cylinder and a
cylinder of larger diameter than and in substan
tially axial. alignment with said second mentioned
cylinder and connected to said trailer brake, a
‘piston within said second mentioned cylinder op
erable by the ?uid forced from said master cylin
der, a second piston within said third mentioned
cylinder directly subject to the pressure of air in
said third mentioned cylinder and connected to
said first mentioned piston to transmit the pres
2,413,818
sure of air to said first mentioned piston in oppo
sition to the ?uid pressure, and a valve connected
to and movable in unison with said pistons for
controlling the ?ow of air to said trailer brake
and to said third mentioned cylinder.
2. A control device in a tractor-trailer brake
system of the type wherein the tractor is equipped
with a brake and a master cylinder for applying
4. A control device in a tractor-trailer brake
system of the type wherein the tractor is equipped
with a brake and a master cylinder for applying
said brake by ?uid under pressure and wherein
the trailer is equipped with a brake operable by
?uid under pressure separate from the ?rst men'
tioned ?uid, said device comprising a housing
memberhaving a cylinder communicating with
said master cylinder and another cylinder in sub
said brake and wherein the trailer is equipped
with a brake operable by compressed air, said 10 stantially axial alignment with said second men
tioned cylinder and connected to said trailer
device comprising a housing member having a
brake, a piston within said second mentioned
cylinder connected to said master cylinder and a
cylinder operable by the ?uid forced from said
cylinder of larger diameter than and in substan
master cylinder, another piston within said third
tially axial alignment with said second mentioned a
cylinder and connected to said trailer brake, a 15 mentioned cylinder subject to the pressure of the
second mentioned ?uid in said third mentioned
piston within said second mentioned cylinder op
cylinder and connected to said ?rst mentioned
erable by the fluid forced from said master cylin
piston to transmit the pressure of the second
der, a second piston within said third mentioned
‘ mentioned ?uid to said ?rst mentioned piston in
cylinder subject to the pressure of air in said third
mentioned cylinder and connected to said ?rst 20 opposition to the pressure of the ?rst mentioned
?uid, and a valve connected to and movable in
mentioned piston to transmit the pressure of air
unison with said pistons for controlling the flow
to said ?rst mentioned piston in opposition to
of the second mentioned ?uid to said trailer
the ?uid pressure, and a valve between and con
brake and to said third mentioned cylinder.
nected to said pistons for controlling the ?ow of
5. A control device in a tractor-trailer brake
air to said third mentioned cylinder, said valve 25
and second piston having registering longitudi
system of the type wherein the tractor is equipped
with a brake and a master cylinder for applying
said brake by ?uid under pressure and wherein
3. A control device in a tractor-trailer brake
the trailer is equipped with a brake operable by
system of the type wherein the tractor is equipped
with a brake, a master cylinder for directly ap 30 ?uid under pressure separate from the ?rst men
I tioned ?uid, said device comprising a housing
plying said brake by ?uid under pressure, and a
member having a cylinder communicating with
manually operable member for operating said
nally extending passageways for air.
q
master cylinder and wherein the trailer is
equipped with a brake operable by ?uid under
- said master cylinder and another cylinder in
said device comprising a housing member hav
ing a ?uid inlet communicating with said master
trailer brake, a piston within said second men
tioned cylinder operable by the ?rst mentioned
?uid, a second piston within said third mentioned
cylinder subject to the pressure of the second
substantially axial alignment with said second
pressure separate from the ?rst mentioned ?uid, 35 mentioned cylinder and communicating with said
cylinder, an inlet and an outlet for the second
mentioned ?uid, a piston member within said
housing member operable by the ?uid forced from 40 mentioned ?uid and connected to said ?rst men
tioned piston to transmit the pressure of the
said master cylinder through said ?uid inlet, a
second mentioned ?uid to said ?rst mentioned
valve connected to and movable in unison with
piston in opposition to the pressure of the ?rst
said piston member and controlling the flow of
mentioned ?uid, and a valve between and con
the second mentioned ?uid from said second
mentioned inlet to said outlet to operate said 45 nected to‘ said pistons for controlling the flow
of the second mentioned ?uid to said third men
trailer brake, and a passageway for transmitting
tioned cylinder, said valve and second mentioned
the pressure of the second mentioned ?uid in
piston having registering longitudinally extend
said outlet directly to said piston member in op
ing passageways for the second mentioned ?uid.
position to the pressure of the ?rst mentioned
JOSEPH A. FORBES.
?uid created by said master cylinder.
50
Документ
Категория
Без категории
Просмотров
0
Размер файла
547 Кб
Теги
1/--страниц
Пожаловаться на содержимое документа