Note: Descriptions are shown in the official language in which they were submitted.
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CAST REINFORCED B~CK~T
~ACKGROUND OF THE ~NVENTION
Field of the Invention
The present invention relates to cast metal brackets,
and, more specifically, to cast metal brackets having an embedded
stiffening plate.
Description of the Related Art
Cast metal brackets are frequently used as support
members in applications where the bracke~ must be formed in a
special shape or configuration. A typical application is a
mounting bracket for an internal combustion engine. The bracket
is bolted to the engine and has support members extending
outwardly for supportin~ components such as an alternator, power
steering pump, or any o~ a wide variet~ of devices.
In an application such as an internal combustion
engine, the bracket must be specially shaped to avoid
interferences with other components in the typically crowded
engine compartment of modern vehicles. Furthermore, it i9 highly
desirable to make the bracket as light in wei~ht as possible to
improve fuel economy. To meet these end~, such brackets will
often be configured with rather slender support members and thin
wall thicknesses. Cast metal, particularly aluminum, is well
suited to meet such requirements.
Brackets as described above, particularly those used on
engines, will be subject to significant stresses. The bracket
must be able to withstand such stresses with out excessive
deflection. Vibrations may be severe, and it is particularly
important that the natural frequencies of the vibration modes of
the bracket be higher than the vibration frequencies of the
engine to which the bracket is mounted; otherwise, the
vibrations of the engine would induce e~cessive bracket vibration
amplitudes and might even cause the bracket to crack and fail.
2~7~t~
One approach to increasing the strength an~ natural
frequency oE vibration of the bracket is to thicken the bracket.
However, this leads to an undesirable increase in weight and
difficulties in fitting the bracket into cramped spaces. A
second approach is to make the bracket out of stronger and
stiffer materials. However, such materials tend to be heavier
and harder. Material hardness is a significant problem in that
machining of the bracket is made more difficult. A third
approach is to manufacture the bracket with an embedded
reinforcing plate, the reinforcing plate being designed to
strengthen and increase the natural ~requency of the bracket as
needed.
Cast metal brackets are usually manufactured by first
casting the metal, machining the ca~ting to obtain precision
surfaces, and by drilling to form holes for bolts or other
fasteners or penetrations. Although the metal used for the outer
body of the casting, typically aluminum, may be readily
machinable, the reinforcing plate material, typically steel, will
be more resistant to machining. Drilled holes will be
particularly di~ficult to produce, since the drill must pass
through the hard reinforcing plate material as well as the softer
outer body material of the bracket.
~ ccordingly, there is a heretofore unmet need for a
cast bra~ket that may be made in shapes suitable for cramped
spaces, that is light in weight yet strong and stiff enough to
resist vibrations, and is readily machinable.
SUMMA~Y OF THE INVENTION
The present invention satisfies the aforemen~ioned need
by providing a cast metal brac~et having an embedded reinforcing
plate, the reinforcing plate having preformed holes which are
larger in diameter tha~ the holes to be drilled through the
bracket. In this manner, the drill bit does not need to cut
through the harder material of the reinforcing plate.
Brackets made according to the present invention may be
made in any desired configuration. Since it is not necessary to
machine through the reinforcing plate, the plate may be made of
extremely strong and tough materials, thus enabling the bracket
to be formed in shapes having thin members which would otherwise
be unable to resist the forces imposed on the bracket.
These and other objects, advantages, and features of
the present invention will be more fully understood and
appreciated by reference to the written specification and
appended drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a front view of a cast reinforced support
bracket for an internal combustion engine according to the
principles of the invention;
Fig. 2 is a perspective view of the rein~orcing plate
u~ed within the bracket of Fig. l;
Fig. 3 i5 a sectional view taken alony the line III-
III of Fig. l;
Fig. 4 i8 a sectional view taken along the line IV-IV
of Fig. l; and
Fig. 5 is a perspective view, partially sectioned, of a
second cast reinforced support bracket according to the
principles of the invention.
DESCRIPTION OF THE PREFERRED EMBODIM~NT
By way of disclosing a preferred embodiment, and not by
way of limitation, there is shown in Fig. 1 a support bracket 10
for an internal combustion engine. In its general organization,
3Q the bracket has a central section 12 which i8 adapted to be
bolted to an engine or an engine component, and outwardly
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extending members 14, 16 which are adapted to support other
engine components such as an alternator 18 and a power steering
pump 20. The central section 12 of the bracket i8 formed with
three holes 22, 24, 26 which are drilled through the bracket.
These holes are provided for the passage of bolts for attaching
the bracket. Other holes 28, 30, 32 are provided for other
fasteners as needed.
The outer body of the bracket is made of a cast metal
such as 380 aluminum chosen for its castability and light weight.
Embedded within the aluminum body of the bracket generally
surrounding a central opening 34 is a steel reinforcing plate 36.
As best shown in Fig. 2, the reinforcing plate is a relative thin
member shaped as a ring having a perpendicularly off3et tongue
38. The shape of the reinforcing plate 36 is specific to the
particular bracket shown in Fig. 1. It should be understood that
the principles of the invention are applicable to an unlimited
variety of other bracket and reinforcing plate shapes, sizes, and
configurations.
The ring portion of the bracket is preformed with three
holes 40, 42, and 44 which correspond in location to the holes
22, 24, and 26 of the finished bracket. As best shown in Figs. 3
and 4, each of the reinforcing plate holes has a diameter
somewhat larger than the holes of the finished bracketO The
reinforcing plate holes are substantially concentric with the
finished holes 22, 24, 26.
Brackets according to the invention are manufactured by
first forming the reinforcing plate with the desired shape and
holes, then supporting the plate in the desired position within
the cavity of a casting die. Molten metal is then poured into
the die. As a result, the reinforcing plate is embedded within
the bracket. Holes such as holes 22, 24 and 26 are then drilled
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through the brac~et. Since the diameters of the reinforcing
plate holes 40, 42, and 44 are greater than the diameters of the
drilled holes 22, 24, and 26, the drill bit cuts only through the
sof~er metal of the body 46 of the bracket, not through the
harder, less machinable reinforcing plate metal. The resulting
bracket is relatively light in weight, yet has sufficient
strength and rigidity to resist the forces imposed by a harsh,
vibrating environment, such as an engine compartment.
Fig. 5 shows a second example of a bracket 50 according
to the invention. The configuration of bracket 50 contains a
number of bends 52, 53, 54, surfaces 56, 57, 58, and a relatively
narrow neck 60. The steel reinforcing plate 62 is conveniently
bent, shaped, and preformed with holes such as hole 64 to be
embedded within the cast aluminum body 66 in khe same manner as
descri~ed above.
The above description is that of a preferred embodiment
of the invention. Various alterations and changes can be made
without departing from the spirit and broader aspects of the
invention as set forth in the appended claims, which are to be
interpreted in accordance with the principles of patent law,
including the Doctrine of Equivalents.
