Light weight component (FIG. 1) comprising hollow, tubular member (A) with load transmission means (B) at its ends and filaments (E) in a plastic matrix C encircling the member and transmission means may be used as tension compression member. The tubular member preferably is a pultrusion adapted to contain sufficient filaments to tensilely strengthen the component. The component may be made, for example, by winding or wrapping filaments about the member while load transmission means are at its ends.

BACKGROUND OF THE INVENTION 
This invention relates to a lightweight structural component. More 
particularly, this invention relates to plastic composites suitable for 
such applications as vehicular lower control arms. 
The need for lighter weight vehicular components is widely known, 
particularly with respect to automotive applications. Moreover, the 
potential of plastic or other lightweight materials to satisfy such need 
as to structural components is established. Anisotropic behavior of many 
reinforced plastics, however, complicates effective substitution of such 
plastics for metal. Moreover, even when a design utilizes anisotropic 
materials effectively, manufacturing considerations may limit its 
implementation. 
Design and manufacture of components that are to withstand tensile and/or 
compressive loads are known (e.g., see U.S. Pat. Nos. 3,228,481; 
3,286,547; 3,362,252; 3,434,899; 3,460,628; 3,470,051; 3,542,079; 
3,607,510; 3,673,028; 3,691,000; 3,769,127; 3,850,722. Included among 
these patents are disclosures of lightweight structural components. None 
of these patents, however, show manufacture or design components that 
withstand repetitive tensile and compressive loads and which comprise load 
transmission means at the ends of a hollow tubular member longitudinally 
encircled by filaments in a plastic matrix as in this invention. 
It is an object of this invention to provide lightweight structural 
components which withstand repetitive tensile and compressive loads in 
use. 
It is an object of this invention to provide such lightweight components 
which are conveniently manufactured. 
It is an object of this invention to provide manufacturing techniques for 
such lightweight components. 
These objects and others have been accomplished by this invention as may be 
seen from the hereinafter disclosure.

BRIEF DESCRIPTION OF THE INVENTION 
This invention relates to a lightweight structural component that has a 
hollow tubular member with load transmission means at its ends and in 
which there is a band comprising filaments in a plastic matrix that 
longitudinally encircle said component and said load transmission means. 
More particularly and preferably, the lightweight component in accordance 
with this invention comprises (A) a first tubular member, (B) a second 
tubular member located near one end of said first tubular member such that 
its center longitudinal axis is at least substantially perpendicular to 
the center longitudinal axis of said first member, (C) a third tubular 
member located near the other end of said first tubular member such that 
its center longitudinal axis lies in substantially the same plane as said 
center longitudinal axis of said second tubular member and (D) filaments 
in a plastic matrix that encircle said first tubular member so as to 
restrain said second and third tubular members. 
In preferred embodiment, the first tubular member comprises a hollow, 
pultruded, reinforced plastic beam, preferably comprising continuous and 
matted fibers. The beam comprises two opposite longitudinal faces having 
tabs that project perpendicularly along each face. The tabs form a trough 
shaped cavity of sufficient depth to contain a tensely strengthening 
amount of filaments for the component. The filaments are wound or wrapped 
along such faces during manufacture of the component. The second and third 
tubular members each comprise a rigid hub that contains elastomeric 
material. In the elastomeric material a second hub or other means for 
attaching the component lies along the center longitudinal axis of the 
rigid hub. The filaments in plastic matrix comprise one or more strands of 
glass or other reinforcing fiber. 
In making the preferred component, the pultruded beam is adapted to receive 
the rigid hubs at its ends, the hubs are positioned at the ends, and 
filaments are wound or wrapped about the beam and so as to contain the 
hubs at the ends of the beam. The filaments may be dipped in resin and 
wound lengthwise about the component or alternatively, or in addition, be 
in a resin tape that also is wound or layed lengthwise about the 
component. 
DETAILED DESCRIPTION OF THE INVENTION 
This invention has particular application to components that are exposed to 
repeated tensile and compressive loads. For example, lower control arms in 
automobiles act to maintain alignment of the rear axle and frame. These 
lower control arms extend between the axle and frame or lower body 
structures and maintain a fixed relationship therebetween. 
FIGS. 1, 2 and 3 show, respectively, an end of a component of this 
invention, a section taken around II--II of FIG. 1 and a section taken 
around III--III of FIG. 1. Since the component is symetrical, only one end 
need be illustrated. 
In these figures, it can be seen that filaments E in plastic matrix C 
encircle hollow tubular member A and bushing B. The filaments E in plastic 
matrix C encircle lengthwise tubular member A so as to similarly contain a 
bushing at the other end (not shown). 
The end of tubular A is adapted to receive bushing B and particularly 
bushing outer hub BOH. Interposed between tubular member A and bushing B 
are end caps RM and LM that protect the end of tubular member A. End caps 
RM and LM fit on either side of end of member A and are bonded thereto by 
suitable adhesive. 
Hub member BOH has welded flanges LF and RF that partially encircle BOH. 
Flanges LF and RF serve to help contain filaments as they are wrapped or 
wound about BOH during manufacture of the component. 
Within hub member BOH is elastomeric material BE that acts to cushion loads 
applied to the component. Within elastomeric material BE is attachment 
means for the component which in the case of this embodiment is inner hub 
BIH. In use, a pin (not shown) or other load attachment means is mounted 
to hub BIH. 
As shown more particularly in FIGS. 2 and 3, tubular member A is hollow and 
of rectilinear cross section. As seen particularly from FIG. 1, tubular 
member A comprises longitudinal fibers AL interspersed in fiber matt AM. 
Although member A may be of any configuration, the rectilinear 
configuration shown has advantage with respect to its manufacture (e.g., 
pultrusion using reinforcing fiber) as well as in manufacture of the 
component. 
Tabs or flanges LLT, LRT, ULT and URT respectively project from the surface 
of tubular member A and serve as guides and form channels for filaments E 
in plastic matrix C during manufacture. The inner well between each set of 
tabs, ULT and URT and LRT and LLT, respectively preferably have adhesive 
so as to bond filaments E in plastic matrix C to tubular member A. 
Filaments E in plastic matrix C comprise one or more strands of 
reinforcing filaments. They may be applied to the component by a filament 
winding or tape winding process. 
The embodiment of FIG. 4 differs from that of FIG. 1 in that end caps RM 
and LM are omitted. Additionally, the component of FIG. 4 has lugs RL and 
LL which are integral with bushing B. Lugs RL and LL are affixed (e.g. 
press fit or welded) around the circumference of bushing outer hub BOH. 
Also, they are bonded to tubular member A by suitable adhesive (e.g., 
epoxy film type). Lugs RL and LL also serve to transmit loads to the sides 
of hollow tubular member A. 
The hollow tubular member such as A of FIGS. 1, 2 and 3 (or A of FIG. 4 
which is the same as A of FIGS. 1, 2 and 3) is preferably made by a 
pultrusion process. For example, continuous filaments may be drawn through 
a resin and pulled through a die along with a chopped fiber matt to 
provide a continuous pultrusion section. The pultrusion thus has 
longitudinal continuous fibers interspersed in a plastic matrix that 
additionally has embedded fibrous matt of longitudinal and transverse 
fibers. Preferably, the fiber reinforcement comprises at least about 50% 
by weight of the combined weight of fiber and resin and is glass or carbon 
fiber or both. 
The resin is preferably thermosetting and may be epoxy, vinyl ester, 
polyester and the like and in which case it may be cured (e.g., by 
heating) as the section during its passage through the pultrusion die. 
After cure, the section is cut to length and preferably adapted to receive 
load transmission means at either end. This may be done by simply shaping 
(e.g., cutting) the ends of the pultruded section so as to receive a 
bushing or other load transmission means. 
With the bushings fitted to the ends of the hollow, pultruded member, a 
winding or wrapping operation provides a band that lengthwise encircles 
the tubular member so as to lock the bushings firmly in place. Lugs such 
as L and RL of FIG. 4 may be used to adhere the bushing to the side of the 
hollow pultruded beam, if desired. Thus, for example, one lug may be 
welded or otherwise fixed (e.g. press fitted) to each bushing and 
thereafter, the assembly mounted on the ends of the pultrusion. The other 
lug may be then similarly fitted and the band comprising filaments wound 
or wrapped about the assembly. 
The filaments in the plastic matrix preferably comprise several strands of 
fiber. Preferably, the fiber weight of these filaments wound or wrapped 
lengthwise about the component comprise glass or graphite or both at least 
about 60% by weight of the total weight of resin and fibers. In winding or 
wrapping operations, the assembly of bushings at the end of the adapted 
pultruded beam may be placed under compressive load, for example, 
1500-2500 lbs. Release of the load upon completion of winding or wrapping 
operations then provides a predetermined tension to the filaments E 
surrounding the component. Alternatively or, in addition, the filaments 
(e.g, 100-300) may be wound or wrapped under a desired tension of, for 
example, 1-15, preferably 5-10 lbs. each. 
The components of this invention withstand repeated tensile and compressive 
loads. Filaments E carry a tensile load applied to bushing B in the 
embodiment of FIGS. 1, 2 and 3. Beam A carries compressive load in this 
embodiment. In the embodiment of FIG. 4, lugs RL and LL and the lugs at 
the other end share compressive and tensile loads and transmit such loads 
to tubular member A. 
Component of this invention withstand repeated loads of about =6300 lbs. 
Minimum load is about 11,000 lbs. The component functions at temperatures 
varying between -40.degree. F. to 200.degree. F.