Elastomeric hanger structure

An elastomeric hanger structure is designed to provide both force stabilization and vibration isolation while connecting a part such as a vehicle exhaust system with a supporting structure such as a vehicle chassis. The elastomeric hanger of the invention is also capable of being selectively tailored to control numerous static and dynamic conditions which may be encountered when the part is suspended.

FIELD OF THE INVENTION 
The present invention relates to an elastomeric hanger structure for use in 
connecting a part (e.g., a portion of vehicle exhaust system) with a 
supporting strucutre (e.g. a vehicle chassis). More specifically, the 
present invention relates to a new and useful elastomeric hanger structure 
designed to stabilize a part of an exhaust system to provide vibration 
isolation of the part and of the chassis, and to provide a fail-safe 
structure which can prevent the vehicle exhaust system from dropping onto 
the vehicle suspension or the ground in the event of failure of the 
elastomer. 
BACKGROUND ART 
Heretofore, vehicle exhaust systems have typically been hung from the 
underside of the vehicle's chassis by means of supporting brackets. Such 
brackets have generally been merely pieces of metal or rubber designed to 
connect the exhaust system to the vehicle without regard to force 
stabilization, vibration isolation, and the like. 
SUMMARY OF THE INVENTION 
The present invention relates to a new and useful elastomeric hanger 
structure specifically designed to provide both force stabilization and 
vibration isolation while connecting a part such as a vehicle exhaust 
system with a supporting structure such as a vehicle chassis. The hanger 
of the invention is also capable of being selectively tailored to control 
numerous static and dynamic conditions which may be encountered by the 
part during suspension thereof. 
One important aspect of the hanger of the present invention is the manner 
in which the elastomeric design or configuration of the hanger provides 
vibration isolation and enables the hanger to be specifically configured 
or shaped for controlling numerous selected static and dynamic conditions. 
Specifically, the elastomeric hanger of the preferred embodiment has a 
pair of elastomeric coupling portions and an intermediate elastomeric 
portion connecting the pair of coupling portions. Each elastomeric 
coupling portion is designed to engage an attachment such as a bolt for 
connecting the elastomeric coupling portion to either a part or a support 
for the part. At least one of the elastomeric coupling portions comprises 
an inner section and is generally spaced therefrom. A web means connects 
selected portions of the inner and outer sections. The web means is 
designed to deflect under the application of predetermined forces to the 
hanger, thereby enabling the inner section to move relative to the outer 
section in response to forces which cause the web means to deflect. The 
web means can be designed with predetermined deflection characteristics by 
controlling features such as the thickness of the material, the 
composition of the elastomeric material, the hardness (durometer) of the 
elastomeric material, and the like. 
Another important aspect of the hanger of the present invention is the 
provision of a special metal reinforcing means. The metal reinforcing 
means is preferably embedded in the elastomeric material and is covered by 
the elastomeric material so that it is protected against corrosion by the 
elastomeric material. The metal preferably circumscribes each of the 
elastomeric coupling portions in the elastomer, and extends through the 
intermediate elastomeric portion of the hanger. Thus, the metal provides a 
fail-safe backup against failure of the elastomeric material, and such a 
feature is especially useful in minimizing the likelihood of a vehicle 
exhaust system from falling onto the vehicle suspension or onto the ground 
in the event of failure of the elastomer. Additionally, the orientation of 
the metal reinforcement, and the orientation of the elastomeric coupling 
portions of the hanger are specially designed so that the metal also 
provides a certain degree of lateral stability to the elastomeric hanger 
structure. 
These and other aspects of the present invention will become apparent from 
the following detailed description and the accompanying drawings.

DETAILED DESCRIPTION OF THE INVENTION 
The present invention relates to an elastomeric hanger structure for 
connecting a part such as a vehicle exhaust system with a supporting 
structure such as the chassis of a vehicle. FIGS. 1 through 4 and 5 
through 11 show two different forms of elastomeric hanger structures 
constructed according to the concepts of the present invention, and FIGS. 
12 and 13 show another form of a hanger structure according to the present 
invention connecting two bracket members. 
In FIGS. 1 through 4, hanger structure 10 basically comprises a first 
elastomeric coupling portion 12, a second elastomeric coupling portion 14 
and an intermediate elastomeric connection portion 16 connecting the first 
and second elastomeric coupling portions 12 and 14. A length of corrosion 
resistant steel wire 18 and a ring of the steel wire 19 are embedded in 
the elastomeric material in a manner and for purposes discussed more fully 
hereinafter. 
In the hanger of FIGS. 1 through 4, the first elastomeric coupling portion 
12 comprises a body 20 of elastomeric material having central opening 22. 
The opening 22 is designed to receive an attachment means such as a 
connecting bolt for coupling the first portion 12 of the hanger with a 
bracket of either a vehicle chassis or a part of the vehicle's exhaust 
system. The second portion 14 comprises a body 30 of elastomeric material 
configured to define (i) an inner portion 31 with a central opening 32 
(ii) an outer portion 34 surrounding the inner portion 31, (iii) a pair of 
webs 36 extending between the inner and outer portions 31 and 34, and (iv) 
a pair of openings 36A formed within the webs 36. The central opening 32 
is designed to receive an attachment means such as a connecting bolt for 
coupling the second portion 14 of the hanger with the bracket associated 
with the vehicle chassis or part of the vehicle's exhaust system. The 
configuration of the web 36 and the openings 36A formed in the webs is 
designed to provide the hanger structure with predetermined deflection 
characteristics to enable the hanger to absorb forces and vibrations and 
to stabilize and/or isolate such forces or vibrations from being 
transmitted between the exhaust system and the vehicle chassis. The 
specific deflection characteristics of the hanger can be modified by 
altering the specific shape or form of the web 36, the openings 36A, the 
thickness of the elastomer, the composition of the elastomer, and the 
like. 
The modification of the elastomeric hanger to provide for different static 
and dynamic conditions such as force stabilization and vibration isolation 
can be made in accordance with existing scientific and mechanical 
principles known to the art and to the literature, as for example set 
forth in THEORY AND PRACTICE OF ENGINEERING WITH RUBBER by Freakley and 
Payne, Applied Science Publishers LTD, London, England, 1978, and 
ELASTOMERS: CRITERIA FOR ENGINEERING DESIGN by Hepburn and Reynolds, 
Applied Science Publishers LTD, London, England, 1979, both of which are 
hereby fully incorporated by reference. For example, should the elastomer 
hanger of FIGS. 1 through 4 be required to carry a load about twice as 
heavy as the designed load, it can be redesigned to compensate for the 
additional weight by increasing the thickness of the hanger as for example 
in intermediate connecting portion 16, by increasing the thickness, i.e., 
width or depth, of steel wire 18, by changing the hardness (durometer) or 
composition of the rubber, by changing the configuration of the web and/or 
its support angle, or combinations of the above. For pragmatic reasons, 
such as making as few a number of dies as possible, the easiest solution 
is to increase the hardness or durometer of the rubber. Increasing the 
hardness of the rubber is conventional and is well known to the art and to 
the literature. Hence, force stabilization and/or vibration isolation can 
be readily controlled by increasing the durometer hardness of the rubber. 
The Shore A durometer hardness of the rubber can vary widely, as from 
about 40 to about 75, and preferably from about 50 to about 65. 
According to an aspect of the present invention, the steel wire 18 and the 
steel ring 19 are embedded in the elastomeric hanger. As seen in FIGS. 
1-4, the steel wire 18 is a single length of wire embedded in the 
elastomer so that the wire surrounds the central opening 22 in the first 
elastomeric coupling portion 12, that the wire extends through the 
intermediate elastomeric connecting portion 16, and that the wire extends 
into the outer portion 34 and circumscribes the central opening 32 in the 
inner portion 31 of the second elastomeric coupling portion 14. The metal 
ring 19 is provided in the inner portion 31, and also surrounds the 
central opening 32. 
Wires 18 and 19 are embedded in the elastomer in such a manner that the 
metal wires are coated, covered, etc. by the elastomer from corrosive 
materials during normal operation of the hanger. Thus, the wires serve to 
reinforce the elastomer and in a manner that minimizes the likelihood of 
corrosion of the wires. 
Steel wire 18 also provides a fail-safe mechanism for ensuring that the 
exhaust system does not drop onto the vehicle suspension or onto the 
ground in the event of failure of the elastomeric material. Specifically, 
since the wire completely surrounds both of the central openings 22 and 32 
formed in the elastomeric coupling portions, it can engage the connecting 
bolts associated with the elastomeric coupling portions and thus retain 
the exhaust system attached to the chassis in the event of failure of the 
elastomer. 
An important aspect of the metal wire of the present invention is that it 
not only provides a connection with good vibration isolation and/or force 
stability between the exhaust system and the chassis, but it also provides 
a connection with good lateral stability. Specifically, the central 
openings 22 and 32 in the elastomeric hanger extend parallel to each 
other, and the elastomeric web parts 36, 36A enable the hanger to deflect 
in order to take up strains which act parallel to the axis of openings 22 
and 32. The steel wire 18 is disposed to allow the web to deflect, but 
minimizes the tendency of the hanger to move in the direction of the axes 
of central openings 22 and 32. Another important aspect is that the 
cantilevered portion of the metal wire which is located in intermediate 
elastomeric portion 16, also serves to dampen or abate lateral forces 
applied to the metal hanger. Hence, the metal wire as well as web means 
36A provide lateral stability. 
FIGS. 5 through 11 disclose another embodiment of the elastomeric hanger 
constructed according to the concepts of the present invention. The hanger 
of FIGS. 5 through 11 differs from the hanger of FIGS. 1 through 4 
primarily in that (i) the profile of its web portions 36' are different 
(they lack openings); (ii) the profile of its intermediate connecting 
portion 16'; and (iii) the shape of its metal wire 18'. However, the metal 
wire still extends into and through the elastomer, and is shielded by the 
elastomer during normal operation. Additionally, the metal is disposed in 
such a way that it provides a fail-safe reinforcement for the elastomer in 
the event of failure of the elastomer. 
The elastomeric hanger of the invention is preferably a molded part. As 
shown in FIGS. 5, 8 and 11, the elastomeric portions of the hanger of 
FIGS. 5 through 11 has locator holes 40 (FIGS. 5, 8) and 42 (FIGS. 5, 9, 
10, 11). Those locator holes are associated with the metal wires. They 
result from the inclusion of locator pins in the mold, which enables the 
metal wires to be molded into the elastomer. 
In FIGS. 12 and 13, still another hanger according to the invention is 
shown connecting a first bracket 50 to a second bracket 52. The bracket 52 
could be connected with a vehicle exhaust system, and the bracket 50 could 
be connected with a vehicle chassis. The elastomeric hanger is reinforced 
with a metal wire (not shown) and has a profile designed to allow a 
predetermined deflection of its web 60 in order to isolate vibrations and 
to provide a good lateral stability to the exhaust system. 
The embodiments of FIGS. 5 through 11 and 12 and 13 can also be altered in 
a manner as set forth above with regard to the embodiment of FIGS. 1 
through 4, so that the elastomeric hanger can be tailor-made to handle 
various static and dynamic conditions such as deflection, vibration, force 
stabilization, and the like. As noted above, this can be accomplished by 
increasing or decreasing the thicknesses of the various elastomer 
portions, by increasing or decreasing the thickness of the metal insert 
19, by changing the configuration of the web, or preferably by increasing 
or decreasing the durometer hardness of the rubber. 
While in accordance with the patent statutes, the best mode and preferred 
embodiment has been set forth, the scope of the invention is not limited 
thereto, but rather by the scope of the attached claims.