Expansible chamber devices – Cylinder detail – With reinforcing member
Reexamination Certificate
2001-05-17
2003-04-01
Look, Edward K. (Department: 3745)
Expansible chamber devices
Cylinder detail
With reinforcing member
Reexamination Certificate
active
06539837
ABSTRACT:
TECHNICAL FIELD
This invention relates generally to the field of vacuum brake boosters for cars or light trucks, and in particular, to an apparatus and method of attaching a connecting member and a tube member to a housing of a vacuum brake booster.
BACKGROUND OF THE INVENTION
Vacuum brake boosters are typically used in automobiles and light trucks. They typically include a housing that includes a front side and a rear side. The rear side is typically attached to the firewall of the vehicle, while the front side provides an attachment for a master-cylinder. In order to fasten the vacuum booster to the firewall, rigid tubular members are provided, which extend through the front side of the housing, through the interior of the booster, and through the rear of the housing. Fastening bolts can then be inserted into the tubular members to allow the booster to be attached to the firewall.
Various arrangements are known for attaching a tubular member to the housing of a vacuum brake booster. An example of a conventional arrangement is shown generally in FIG.
10
. As shown in
FIG. 10
, at least four parts are required: namely, a tubular member
100
, a fitting
102
, a nut
104
and a seal
106
. One end
108
of the tubular member
100
is connected and sealed to the front side
110
of a housing
112
via the fitting
102
by slightly deforming the metal structure of the fitting
102
. That is, the one end
108
of the tubular member
100
is crimped against the fitting
102
, which itself is crimped against the front side
110
of the housing
112
. The nut
104
and the seal
106
are positioned adjacent to an inner surface
114
of a rear side
116
of the housing
112
. The nut
104
and seal
106
facilitate the connection and sealing of a second end
118
of the tubular member
100
to the rear side
116
of the housing
112
. EP 0 623 081, for example, discloses a similar arrangement for attaching and sealing a tubular member to the front housing of a vacuum brake booster.
There are several disadvantages to this arrangement, including the number of parts required (i.e. the nut
104
, and the seal
106
). The increased number of parts in turn increases the costs associated with the vacuum brake booster. Moreover, the installation of these parts is a labor intensive and time-consuming process, which also increases the costs associated with installing the booster. In addition to the above, the crimping arrangement associated with the fitting
102
and the front side
110
of the housing
112
cannot be implemented to flush mount a rear side of a booster housing to a firewall due to the interference that would caused by the threaded fitting
102
.
Another example of a conventional apparatus is shown in FIG.
11
. As shown in
FIG. 11
, the tubular member
200
consists of a first tube portion
202
and a second tube portion
204
. The first tube portion
202
is linked mechanically to a rear housing
206
and the second tube portion
204
is mechanically linked to a front housing
208
. The bolt
210
may extend through the tubular member
200
from the front housing
208
to the rear housing
206
. A flange
212
positioned adjacent to an end of the bolt
210
prevents the master-cylinder from compressing the booster. EP 0 331 535, for example, discloses a similar arrangement for providing a tubular member in a vacuum brake booster.
There are also several disadvantages to this arrangement. For example, it is very impractical and difficult to manufacture and assemble the first and second tube portions
202
,
204
so that they are a part of the housings
206
,
208
, respectively. This arrangement is also likely to require additional parts. The large number of parts required, and the complexity of the interconnections between parts, also results in increased costs.
Another example of an apparatus and method of assembling a brake booster is shown in U.S. Pat. No. 5,487,327 (“the '327 patent”).
FIGS. 2 and 3
from the '327 patent are reproduced herein as
FIGS. 12A and 12B
. As shown in
FIGS. 12A-12B
, the booster housing is assembled by first inserting an end portion
52
of the spacer
50
(i.e. tubular member) into a recess
40
of a connecting member
32
. The connecting member
32
is then passed through a fastening hole
30
. The two tool members B and C are compressed, which simultaneously crimps the connecting member
32
with the housing
26
and the spacer
50
.
FIG. 12A
shows the apparatus before crimping, while
FIG. 12B
shows the apparatus after crimping. The disadvantage of this arrangement is that it cannot be used to mount a rear side of a booster housing flush with the firewall of the vehicle.
Accordingly, it would be desirable to have an apparatus and method of attaching a connecting member and a tube member to a housing of a vacuum brake booster that overcomes the disadvantages described.
SUMMARY OF THE INVENTION
One aspect of the invention provides a connecting member including a cylindrical body portion having a first end and a second end. A rim portion is formed between the first end and the second end, and a stem portion is formed at the second end of the cylindrical body portion. The stem portion includes a tapered end portion to allow the stem portion to flow radially outward when a force is applied to the stem portion. The cylindrical body portion further includes a first opening formed in the cylindrical body portion adjacent to the first end of the cylindrical body portion for receiving an end portion of tube member. The cylindrical body portion also includes a second opening in communication with the first opening. The first opening has a first diameter and the second opening having a second diameter, the second diameter being less than the first diameter. The stem portion is adapted to be deformed to create a seal between a portion of a housing member and the connecting member. The rim portion and the stem portion may preferably define a recess to receive the housing member. The rim portion may preferably extend outward from the cylindrical body portion in a direction towards the second end. In particular, the rim portion may preferably extend outward from the cylindrical body portion approximately 25 degrees from vertical. The cylindrical body portion may be formed from a single piece of rigid material.
Another aspect of the invention provides a vacuum brake booster including a housing member and a connecting member including a cylindrical body portion. The cylindrical body portion includes a first end and a second end. A rim portion is formed between the first end and the second end, and a stem portion is formed at the second end of the cylindrical body portion. The stem portion includes a tapered end portion to allow the stem portion to flow radially outward when a force is applied to the stem portion. The cylindrical body portion further includes a first opening formed in the cylindrical body portion adjacent to the first end of the cylindrical body portion. The cylindrical body portion also includes a second opening in communication with the first opening. The first opening has a first diameter and the second opening has a second diameter. The second diameter is less than the first diameter. The stem portion is deformed to create a seal between a portion of a housing member and the connecting member. A tube member includes a first end portion, which is received in the first opening of the cylindrical body portion. An outer surface of the stem portion may preferably be flush with an outer surface of the housing member.
Another aspect of the invention provides a method of attaching a connecting member to a housing member of a vacuum brake booster. The connecting member includes a cylindrical body portion having a first end and a second end. A rim portion is formed between the first end and the second end, and a stem portion is formed at the second end of the cylindrical body portion. The stem portion includes a tapered end portion. The cylindrical body portion further includes a first opening formed in the cylindrical body portion
Castel Philippe Georges
Fanelli Michael William
Van Doren William Lee
Delphi Technologies Inc.
Lazo Thomas E.
Look Edward K.
Sigler Robert M.
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