One piece bumper-bellows subassembly

The present invention is directed to a one piece, integrally molded, bumper-bellows subassembly for use in vehicles, for example, for use in suspension systems, rack and pinion steering systems and airsprings. The present subassembly prevents the elements from entering the bottom of the subassembly and thus eliminates the possibility of damage to the piston rod and seals of the damper. The present subassembly is cost-effective to produce and can be installed quickly and easily. During operation, the present subassembly is stable and is not affected by a severe drop in the suspension.

FIELD OF THE INVENTION 
The present invention relates to a one piece, integrally molded, 
bumper-bellows subassembly for use in vehicles, for example, for use in 
suspension systems, rack and pinion steering systems and airsprings. 
BACKGROUND OF THE INVENTION 
Dampers (shock absorbers and struts) are used in automobile suspension 
systems. The telescopic piston rod and seals of a damper must be protected 
from the elements. Further, the mount assembly, bearing, and damper must 
be protected from coming in contact with one another during suspension 
travel. 
A jounce bumper is a tubular member that is slipped over the piston rod of 
the damper. The jounce bumper protects the mount assembly from coming into 
contact with the striker plate of the damper. The jounce bumper is 
compressed as a damper bottoms out on a compression or jounce stroke to 
dissipate jounce energy, thus, protecting the mount assembly. 
A bellows (dust shield or sheath) is used to protect the piston rod and 
seals from the elements. It has a hollow cylindrical body that is slipped 
over an upper end of the piston rod on the damper. The bellows includes a 
portion of inner and outer convolutions on the outer surface of the body. 
Such convolutions provide a spring-like effect by permitting the bellows 
to be compressed when the damper is in a compression stroke and by causing 
the bellows to expand to its approximate original length during rebound of 
the damper. 
Prior art products are disadvantageous in that each model of automobile 
contains a different damper that requires a different bumper/bellows 
design. As there are well over a 100 different models on the market today, 
and it is not cost-effective to make 100 separate bumpers and 100 separate 
bellows to cover each applicable damper. 
The most common bellows is an elastic sheath. One end of the sheath is 
connected to the jounce bumper by way of a metallic strap or interlocking 
groves, while the other end is open. The connected bumper and bellows is 
slipped over the piston rod of the damper, where the open end of the 
sheath allows it to pass over the reservoir tube of the damper during 
suspension travel. 
This two-piece system is disadvantageous in that the open-ended sheath does 
not prevent the elements from entering the bottom of the unit and damaging 
the piston rod and seals of the damper. Further, the attachment method for 
connecting the jounce bumper and dust shield is a mechanical method that 
uses additional parts (mechanical strap) or interlocking groves to hold 
the two individual parts together. Time must be taken, and alternate 
methods must be used to accomplish connecting the two items. Lastly, the 
multiple part assembly is expensive to manufacture and takes a longer time 
to produce. 
Other systems use a bellows connected to a jounce bumper, through either an 
interlocking grove or a third part (interlocking ring), on one end, and 
mechanically attached to the reservoir tube on the other end with a fourth 
part, i.e., via a tie-strap or clamp. 
This system is disadvantageous in that there are three to four separate 
parts, that require assembly. The connection is also very unstable, for 
example, a severe drop in the suspension (i.e., driving over a pot-hole) 
can cause the bumper and bellows to separate, thereby causing the top of 
the bellows to fall. This in turn causes the exposure of the piston rod 
and seals to the elements. Further, this multiple part assembly requires 
the use of a mechanical tie-strap or clamp that may become unattached from 
the damper, thus causing exposure of the piston rod and seals. There are 
still two openings on either side of the bellows that allow contamination 
of the interior. When installing the unit, it is difficult to fit the 
jounce bumper over the major diameter of the piston rod. Lastly, the 
multiple part system is more expensive to manufacture and takes a longer 
time to produce. 
In another design, illustrated in U.S. Pat. No. 5,275,389, the jounce 
bumper uses a collar that "traps" the bellows between the jounce bumper 
and an upper metal washer. The bellows design in this patent is a 
combination of a sheath and a bellows. This system is disadvantageous in 
that the lower end of the bellows that slips over the reservoir tube is 
open, which exposes the piston rod and seals of the damper to the 
elements. Further, this multiple part system is more expensive and 
time-consuming to manufacture. 
SUMMARY OF THE INVENTION 
The present invention provides an integrally molded, one piece, 
bumper-bellows subassembly for use in vehicles, for example, in suspension 
systems, rack and pinion steering systems and in airsprings. This 
subassembly solves the problems of the prior art devices by providing an 
integrally molded, one piece, bumper-bellows which prevents the elements 
from entering the bottom of the subassembly and thus eliminates the 
possibility of damage to piston rod and seals of the damper. Since the 
subassembly is one part, manufacture of the subassembly is cost-effective 
and time-efficient. Installation of the present subassembly is also quick 
and easy. Since the bumper and bellows are integrally molded, the 
subassembly is very stable. For example, a severe drop in the suspension 
(i.e., driving over a pot-hole) will not affect the subassembly. Whereas, 
in the prior art multiple part assembly such a severe drop in suspension 
can cause the parts to separate thus exposing the piston rod and seals to 
the elements. The present jounce bumper portion of the present subassembly 
is either free-floating in respect to the piston rod or the jounce bumper 
is frictionally fit to the piston rod (i.e., the diameter of the 
passageway of the top end portion of the jounce bumper is equal to or less 
than the diameter of the piston rod). 
In general, either the frictional fit or floating fit can be employed in 
suspension systems where the piston rod itself rotates or in rear strut 
systems that do not employ a steering system. In systems where the piston 
rod does not rotate, the present subassembly having a floating fit is 
preferred to prevent binding of the bellows. 
One object of the present invention is to provide an integrally molded one 
piece bumper-bellows subassembly. 
An object of the present invention is to provide an integrally molded, one 
piece bumper-bellows subassembly where the jounce bumper portion is 
frictionally fit to the piston rod. 
A further object of the present invention is to provide a jounce bumper 
that installs easily over the piston rod, having a tubular body portion, 
upper end portion and lower end portion defining a passageway 
therethrough, and the passageway of the upper end portion defines a top 
inner edge and a bottom inner edge where the bottom inner edge is convex 
relative to the passageway (radius on the jounce bumper inner diameter). 
A further object of the present invention is to provide an integrally 
molded elastomeric collar on a bottom edge of the present subassembly, for 
attaching the subassembly to the reservoir tube of the damper. 
An object of the present invention is to provide an integrally molded 
elastomeric skirt around the elastomeric collar to allow for easy 
installation. 
A further object of the present invention is to provide an integrally 
molded cinch collar on the bottom edge of the bottom end portion of the 
bellows for cinching the bellows portion of the subassembly to the 
reservoir tube of the damper. 
An additional object of the present invention is to provide one or more 
leak detection orifices on the bottom end portion of the bellows portion 
of the subassembly for indicating damper failure. 
An object of the present invention is to provide one or more protection 
flaps near the leak detection orifices to prevent the elements and debris 
from contaminating the piston rod and seals. 
An object of the present invention is to provide a free-floating integrally 
molded bumper-bellows subassembly. 
A further object of the present invention is to provide a tubular boot on 
the lower end portion of the free-floating jounce bumper, with the tubular 
boot in cooperation with the reservoir tube of the damper. 
An object of the present invention is to provide one or more leak detection 
orifices on a bottom end portion of the bellows of the present 
subassembly. 
A further object of the present invention is to provide an integrally 
molded elastic collar or an integrally molded cinch collar, on a bottom 
end portion of the bellows of the present subassembly.

DETAILED DESCRIPTION OF THE INVENTION 
A conventional damper is indicated generally at 10 in FIG. 1 and includes a 
reservoir tube 12 mounting a reciprocating piston rod 14. The damper 10 is 
mounted between a vehicle wheel assembly (not illustrated) and the upper 
mount assembly 20. The piston rod is connected to the upper mount assembly 
20, and seats itself within the thrust bearing 36. The piston rod 14 has a 
smaller diameter that fits within the thrust bearing 42, and is then 
secured to the upper mount assembly 20 by the piston rod nut 30 and washer 
32. The piston rod 14 has a upper planer surface 38 which rests on the top 
of the thrust bearing 36. The upper mount assembly is secured to the 
vehicle body 16 by several studs 26 and nuts 28. Surrounding the system is 
a suspension spring 18. 
The upper planer surface 62 of the jounce bumper 56 is located between the 
damper 10 and the spring seat 22, located beneath the upper mount assembly 
20. At the top of the jounce bumper there is a radius (convex surface edge 
relative to the passageway) 86 on the first bottom edge of the inner 
diameter of the jounce bumper 64 used to ease the jounce bumper 56 over 
the top planer surface 38 of the piston rod 14. The bellows unit 44 is 
integrally molded with the jounce bumper 56 at 76. The bellows unit 44 can 
be molded at any angle relative to the jounce bumper or perpendicular to 
the jounce bumper. The bellows unit is preferably molded to the jounce 
bumper at an angle which places no stress on the subassembly during rest, 
as shown in FIG. 1. The lower planer surface 60 of the jounce bumper 56 
comes into contact with the striker plate 74 of the damper 10 on full 
suspension compression. 
At the base (bottom edge) of the bellows unit 44, there is an integrally 
molded elastic collar 70 and skirt 72, which is used to secure the jounce 
bumper/bellows subassembly to the reservoir tube 12 of the damper 10, and 
to provide ease in installation. The diameter 80 of the collar 70 is less 
than or equal to the diameter of the reservoir tube 12. Above the collar 
70 are two orifices 78 used to detect leaks in the case of damper failure. 
When a strut is damaged or worn, seals may give way and the oil will leak 
and such leaking oil can be detected by visual inspection. 
FIG. 2 is a view using broken lines, and is similar to FIG. 1, absent the 
suspension spring 18. 
FIG. 3 is similar to FIG. 2, and illustrates a preferred embodiment where 
provided on the bottom end portion of the bellows is an integrally molded 
cinch collar 88 instead of the elastic collar 70, for securing the jounce 
bumper/bellows subassembly to the reservoir tube 12 the cinch collar 88 
may include an integrally molded elastomeric strap. 
FIG. 4 is a detailed illustration of upper jounce bumper 56, that shows a 
top planer surface 62, with radius 86 located on the first bottom edge on 
inner diameter 84. The bellows portion (not illustrated) is integrally 
molded with the jounce bumper 56 at 76. 
FIG. 5 is a bottom view of a preferred embodiment, giving the straight on 
view of the elastic collar 70 having internal diameter 80, of the bellows 
which attaches to the reservoir tube (not shown) of the damper (not 
shown). Broken lines detail the leak detection orifices 78 and the outer 
convolutions of the bellows 44. Lastly, the lower skirt 72 is illustrated, 
which is integrally molded to the jounce bumper/bellows assembly. 
FIG. 6 is also a bottom view of a preferred embodiment, giving the straight 
on view of the cinch collar 88 having an internal diameter 80, of the 
bellows which attaches to the reservoir tube (not shown) of the damper 
(not shown). Leak detection orifices 78 and the outer convolutions of the 
bellows 44 are illustrated. The lower skirt 72 is pictured, which is 
integrally molded to the jounce bumper/bellows assembly. Integrally molded 
to the base are cinch tabs 90 used to lock the cinching tab openings 92 
located on the cinching device 88. 
FIG. 7 is a close-up view of the bottom of the bellows portion illustrating 
the cinch collar 88 in a locked position on the cinching tabs 90. 
FIG. 8 shows a longitudinal sectional view of the present subassembly where 
the jounce bumper 56 is free-floating in relation to piston rod 14. The 
bellows unit 44 is integrally molded with the jounce bumper 56 at 76. The 
upper end of the bellows unit 44 is fixed between the mount 20 and the 
spring seat 22. The bellows unit 44 can be molded at any angle relative to 
the jounce bumper 56, but is preferably molded at an angle which places no 
stress on the subassembly at rest. 
FIG. 9 is similar to FIG. 8, and illustrates an embodiment where provided 
on the bottom end portion of the jounce bumper 56 is a tubular boot 96 
integrally molded with the jounce bumper at 94. The tubular boot is shown 
with straight sidewalls, but any shape sidewall is intended, i.e., 
convoluted as in the bellows 44, curved, rippled, etc. 
FIG. 10 is similar to FIG. 9 and shows an embodiment where the jounce 
bumper 56 is disposed between the bellows 44 integrally molded at 76, and 
the tubular boot 96 integrally molded at 94. The sidewalls of the tubular 
boot may be of any shape including straight, convoluted, rippled, curved, 
etc. 
Now having described the invention, it will be understood by those of skill 
in the art that the scope may be performed within a wide and equivalent 
range of conditions, parameters and the like, without affecting the spirit 
or scope of the invention or of any embodiment thereof.