Hanger for vehicle exhaust systems and the like

A hanger for suspending a first component from a second elevated component comprising a first body member formed of a thermoplastic elastomer having a first durometer hardness and a tensile strength sufficient to support the first component, and having a pair of spaced openings therein; a second body member formed of a thermoplastic elastomer having a durometer hardness less than the first durometer hardness, disposed within one of the openings of the first body member and being molded integrally therewith and having an opening therein for receiving an attachment element of the second elevated component; and a third body member formed of a thermoplastic elastomer having a durometer hardness less than the first durometer hardness, disposed within the other of the openings of the first body member and being molded integrally therewith and having an opening therein for receiving an attachment element of the first component; the materials of the second and third body member being compatible with the material of the first body member to permit the molding of the second and third body members with the first body member in a semi-molten state whereby the materials are molded together to provide an integral structure of at least a dual durometer hardness.

This invention relates to a hanger device and more particularly to a hanger 
device suitable for suspending an engine exhaust system from the underside 
of a vehicle body. 
In most vehicles provided with engine exhaust systems, there usually are 
provided various hanger devices for suspending such systems from the 
undersides of the vehicles. Typically, such devices are used not only to 
support the exhaust system but to dampen vibrations to impede the 
transmission of engine vibrations through the exhaust system to the floor 
of the vehicle, and to attenuate sound. To provide such functions, such 
hangers commonly are constructed of an elastomeric material such as rubber 
or various combinations of elastomer materials provided with various 
reinforcing materials such as metals, synthetic materials such as nylon 
and the like. In addition to such functions, such devices provide for 
thermal expansion of the exhaust system components as such components are 
heated during operation of the vehicle. 
Most of such prior art devices, however, have been found not to be entirely 
satisfactory in performance in that they provide for either the use of 
comparatively costly materials or a relatively costly manufacturing 
process. It thus has been found to be desirable to provide a hanger device 
of the type described which not only will provide for adequate support of 
the exhaust system, the dampening of engine vibrations, the attenuation of 
sound and the thermal expansion of the exhaust system components but which 
will be economical to manufacture and which will be consistently effective 
in performance over the service life of the vehicle on which it is 
installed. 
Generally, the present invention provides for a hanger device consisting of 
a first body member formed of a thermoplastic elastomer of a certain 
durometer hardness to provide a tensile strength sufficient to carry the 
load to be suspended from the hanger, and having a set of openings 
therein, a second body member disposed in one of the openings in the first 
body member, formed of a thermoplastic elastomer having a durometer 
hardness less than the durometer hardness of the first body member and an 
opening therein for receiving an attachment element of an elevated 
component, and a third body member disposed in the other opening in the 
first body member, formed of a thermoplastic elastomer also having a 
durometer hardness less than the durometer hardness of the first body 
member and an opening therein for receiving an attachment element of a 
component to be the suspended from the hanger. Although the several body 
members have different durometer hardnesses, they are formed of compatible 
thermoplastic elastomers so that they may be molded together to form an 
integral structure of at least a dual durometer hardness. 
The tensile strength of the hanger is provided by the first body member 
having a greater durometer hardness, and the vibration dampening and noise 
attenuating properties are provided by the second and third body members 
interposed between the first body member and the attachment elements, 
having a lesser durometer hardness. Certain additives such as fiberglass 
and mica can be added to the member compounds to enhance their properties. 
Fiberglass particularly may be added to enhance the tensile strength and 
heat resistant properties of the body members. 
The hanger preferably is formed in an injection molding machine having 
first and second stage molds in which the first body member compound is 
injected into a first set of mold cavities to form the first body member, 
and then, as the first body member compound is in a semi-molten state, the 
second and third body member compounds are injected into a second set of 
mold cavities containing the semi-molten first body member to form the 
final integral structure. The semi-molten state of the first body member 
and the compatibility of the thermoplastic elastomer compounds of the 
several body members permits the resulting structure to form an integral 
molded unit having at least a dual durometer. The particular durometer 
hardnesses of the several bodies are determined by the specific 
application of the hanger although the second and third body members are 
intended to have a lower hardness than the first body member to provide 
the desired vibration dampening and noise attenuating properties of the 
hanger. 
Accordingly, it is the principal object of the present invention to provide 
an improved hanger device particularly suitable for suspending a vehicle 
exhaust system from a vehicle body. 
Another object of the present invention is provide an improved hanger 
device suitable for use in suspending an vehicle exhaust system from a 
vehicle body which is effective in dampening engine vibrations and thus 
impeding the transmission of such vibrations to the vehicle body, 
attenuating sound and providing for the thermal expansion of the exhaust 
system being supported as the exhaust system becomes heated during 
operation of the vehicle. 
A further object of the present invention is to provide an improved hanger 
device for suspending an engine exhaust system from a vehicle body which 
is comparatively simple in design, relatively inexpensive to manufacture 
and highly effective in performance.

Referring to FIG. 1 of the drawings, there is illustrated a hanger device 
10 embodying the present invention which is adapted to suspend a component 
11 of an engine exhaust system from a component 12 of a vehicle body. As 
best shown in FIG. 2, the hanger device consists of a first molded body 
member 13, a second molded body member 14 and a third molded body member 
15, molded together to form an integral unit. Molded body member 13 
includes an annular section 16 providing a cylindrical opening 17 
therethrough, an annular section 18 providing a cylindrical opening 19 
therethrough and a connecting section 20 having a cross-shaped 
cross-sectional configuration. Molded body member 13 is formed of a molded 
thermoplastic elastomer material having a tensile strength sufficient to 
carry the load of the exhaust system which is secured thereto. 
Molded body member 14 is disposed within cylindrical opening 17 and molded 
integrally with annular section 16 of molded body member 13. It is formed 
of a thermoplastic elastomer compatible with the material of molded body 
member 13 to permit the members to be molded together as integral unit, 
and has a durometer hardness less than the durometer hardness of molded 
body member 13. Body member 14 further is provided with an axial opening 
21 for receiving an attachment element such as a bolt 22 for securing the 
hanger device from vehicle body component 12. 
Molded body member 15 is disposed within cylindrical opening 19 of annular 
section 18, and also is molded integrally with annular section 18. It 
similarly consists of a thermoplastic material which is compatible with 
the material of molded body member 13 and also has a durometer hardness 
less than the durometer hardness of molded body member 13. Body member 15 
further is provided with an axial opening 23 adapted to receive an 
attachment element such as a bolt 24 as shown in FIG. 1. Body member 15 
does not entirely fill cylindrical opening 19 in annular section 18 but 
instead spans opposed sides of annular section 18, providing an upper 
space 25 disposed between body member 15 and annular section 18 and a 
lower space 26 between body member 15 and annular section 18. It thus will 
be seen that in addition to the composition of the material of body member 
15, the spacing above and below the body member permits body member 15 to 
displace diametrically relative to annular section 18 to enhance its 
vibration dampening and sound attenuating capabilities. Depending on the 
particular application and requirements of the hanger device, the 
configuration of body member 15 can be enlarged to fill the lower space 26 
and possibly even upper space 25. 
Referring to FIGS. 6 and 7, there is illustrated two sets of molds for 
injection molding the hanger device as described in a two-stage injection 
process. In the first stage, body member 13 is formed with a thermoplastic 
material having a comparatively higher durometer hardness and in the 
second stage, while body member 13 is in a semi-molten state, body members 
14 and 15 are formed by injecting a material having a comparatively lower 
durometer hardness into the second set of molds. As the second 
thermoplastic material is injected into the second set of molds, the 
several body members become molded together to form an integral unit. 
FIG. 6 illustrates a set of molds 27 and 28 having mold cavities 29 and 30, 
and mating surfaces 31 and 32, respectively. The set of molds shown in 
FIG. 6 are disposed at a first station of the injection molding machine 
and provide for the formation of body member 13 by means of the injection 
of a molten thermoplastic elastomer material having a comparatively high 
durometer hardness into mated cavities 29 and 30. 
FIG. 7 illustrates a second set of molds used in the second stage to mold 
the hanger device. The set consists of a mold 27 provided with mold cavity 
29 and a mold 33 having a mold cavity 34 cooperating with mold cavity 29 
and a mating surface 35 engaging mating surface 31 of mold 27 when the 
molds are closed during the second stage of the molding process. In the 
conventional manner, a thermoplastic elastomer material having a durometer 
hardness less than the durometer hardness of the material forming body 
member 13 is injected into mold cavity 34 to become integrally molded with 
body member 13 formed in the first stage of the process and subsisting in 
a semi-molten state. 
The injection molding of the hanger device preferably is performed on a 
machine having a first station in which the first stage molding occurs and 
a second station in which the second stage molding occurs. In the first 
station, molds 27 and 28 are mated to inject the first material to form 
body member 13. The mold sections are then indexed by rotating one mold 
relative to the other to mate molds 27 and 33 while body member 13 remains 
heated in a semi-molten state in cavity 29 of mold 27, and the second 
material is injected into the second set of mold cavities at the second 
station to form body members 14 and 15 and bond them to body member 13 to 
form an integral structure. 
A variety of thermoplastic or thermosetting elastomers can be used for the 
harder and softer materials of the hanger device. Preferably, body member 
13 is formed of a material having a durometer hardness in the range of 40 
to 90 Shore D, and body members 14 and 15 each is formed of a material 
having a durometer hardness in the range of 20 to 90 Shore A. 
In the preferred embodiment of the invention, body member 13 is formed of a 
thermoplastic material and body members 14 and 15 are formed of a 
thermoplastic polyolefinic elastomer consisting of fully cured elastomer 
particles dispersed in a continuous thermoplastic matrix. Body member 13 
may be formed either of a virgin polypropylene material or a polypropylene 
material provided with certain additives depending upon the specifications 
of the hanger. Fiberglass may be added to enhance the strength and 
rigidity of the material. Mica may be added to enhance rigidity to a 
greater extent but would have the added effect of reducing tensile and 
shear strength. The preferred durometer hardness of body member 13 
material is 65.+-.5 Shore D. 
Body members 14 and 15 of the hanger preferably are formed of KRATON G or 
SANTOPRENE. KRATON G is a high performance thermoplastic polyolefinic 
elastomer manufactured and sold by the Shell Chemical Company of Houston, 
Texas. It is a styrene-ethylene/butylene-styrene (SEBS) block polymer 
which exhibits a high temperature, chemical, oxidation and weather 
resistance. SANTOPRENE is a high performance thermoplastic polyolefinic 
elastomer manufactured and sold by the Monsanto Polymer Products Company 
of Akron, Ohio. It is a fully vulcanized polyolefinic material produced by 
a proprietary vulcanization process by Monsanto. The specific hardness of 
body members 14 and 15 is dependent upon the specifications of the hanger. 
Durometer hardnesses of 35.+-.5 Shore A and 55.+-.5 Shore A for body 
members 14 and 15 may be used for different applications. 
From the foregoing detailed description, it will be evident that there are 
a number of changes, adaptations and modifications of the present 
invention which come within the province of those persons having ordinary 
skill in the art to which the aforementioned invention pertains. However, 
it is intended that all such variations not departing from the spirit of 
the invention be considered as within the scope thereof as limited solely 
by the appended claims.