Note: Descriptions are shown in the official language in which they were submitted.
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Background of the Invention
_
The present invention relates to improv~ments in
automotive vehicle suspension systems, and in particular
to spacers insertable between adjacent convolutions of
coil springs of a vehicle suspension system, which
enable the vehicle to ride smoothly in a designed manner
on its suspension under normal driving conditions, but
which progressively stiffen the springs and susp.ension
system under severe driving conditions.
Conventional automobiles have coil springs at
either the front two or all four wheels, which support
the vehicle body and frame. The springs isolate the
body and frame from roadway shocks and undulations
encountered by the wheels, whereby occupants of the
vehicle may ride in comfort, and shock absorbers damp
oscillations of the body and frame on the springs.
Ordinarily, the coil springs have a stiffness or
compressibility which is a compromise between a smooth
ride and good vehicle handling. Soft springs provide
a cushioned ride and afford maximum passenger comfort
on smooth-or slightly undulating roadways. However,
springs which are too soft do not offer sufficien~
resistance to acceleration squat ~r braking dive, or
to collapse and possibly bottoming under heavy vehicle
loads or in response to pronounced roadway undulations
or sharp turns at increased speeds, with the result
that the vehicle body excessively dips and leans and
vehicle handling, roadability and safety are decreased.
Stiff springs, on the other hand, maintain the vehicle
body and frame relatively steady and level or horizontal
for increased load carrying capability, roadability and
handling under severe conditions, but do not satisfactorily
isolate the body from roadwa~ shocks and und~llations,
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so that even on relatively smooth roads a rough ride
may be experienced by passengers. Unless a special
suspension system is installed, conv?ntional
automobiles usually come equipped with springs which
compxomise toward a soft ride. Consequently, the
suspension system of the average automobile is satisfactory
under relatively smooth driving conditions as are
usually encountered the majority of the time, but is
unsatisfactory, and may actually be dangerous~ under
severe roadway or handling conditions or when the
vehicle is heavily loaded.
Previous efforts to improve the suspension systems
of softly sprung automobiles have heretofore proven
generally unsatisfactory. In a first instance, most
are quite expensive and difficult to implement, and in
a second, they usually provide impxoved roadability and
handling only at the expense o~ passenger comfort.
One obvious way to modify a vehicle's suspension
system for improved handling and load carrying capability
is to replace the original coil springs with heavy duty
or relatively stif springs. Unfortunatley, spring
replacement is expensive, and results in an uncomfortably
hard ride under average driving conditions when the
vehicle is not heavily-loaded. A somewhat less expensive
approach, although by no means inexpensive, is to replace
the vehicle's original shock absorbers with load leveler
shock absorbers of the type including separate coil
springs for augmenting the vehicle springs. This latter
technique, however, usually raises the vehicle body
and frame, and also results in a rough or hard ride
under average driving conditions. In another instance,
air pressurized shock absorbers may be installed on the
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vehicle. However, the pressure of the air must be
continuously accommodated to changing vehicle loading
and roadway conditions to maintain satisfactor~
vehicle handling.
Perhaps the least expensive approach heretofore
contemplated to stiffen a vehicle's suspension system
is the insertion of rigid or metal spacers between
adjacent convolutions of the coil springs.
The spacers at all times engage and usually expand the
adjacent convolutions, and absolutely prevent any
movement of the same together during compression of
the remainder of the spring. Although the technique
is often favored because of its economy of implementation,
the resulting ridability of the vehicle under average
driving conditions is harsh.
Objects of the Invention
An object of the present invention is to provide
an improved and economical means for enhancing the
suspension system of an automotive vehicle for improved
handling, roadability and load carrying capahility,
without sacrifice to passenger riding comfort.
Another object is to provide spacer devices for
insertion between one or more adjacent convolutions
of the coil springs of an automotive v~hicle's suspension
system, which do not interfere with limited compressions
o~ the spring~ under normal driving conditions, but
offer resistance to increased compressions of the
springs under severe conditions.
Summary of the Invention
In accordance with the p~esent invention, devices
are provided for insertion between one or more adjacent
convolutions of the coil springs of automotive vehicle
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suspension systems. In one embodimentl the device
comprises a body positionable between adjacent
convolutions of a spring, and the body has a length
between the convolutions which is less than the
spacing therebetween for limited compressions of the
spring, but greater than the spacing that would
otherwise exist for increased compreSsionC;. Consequently,
the bo~y does not impede movement together of the
adjacent convolutions for limited compresC;ions of the
spring, but upon increased compressions engages the
adjacent convolutions and resists further movement
together of the same, thereby to stiffen 1he spring
against further compression. In this mannex, the
device does not interfere with the standard manufacture
height o~ the springs and vehicle, occupants of the
vehicle are afforded a smooth and comfortable ride
under normal drivlng conditions, and yet the vehicle
suspension system is stiffened under severe driving
conditions for improved handling and safety.
The body may be o~ a rigid material, such as metal
or plastic, or of a resilient material, such for
example as rubber. An advantage to a resilient material
body is that the compliance of the body allows the same
to act as a transitional contact member, while at the
same time providing noise isolation upon simultaneous
contact with the adjacent convolutions.
In another embodiment in which the body is of
resilient material, it is configured to normally engage
both of the adjacent convolutions, but to impede
movement together of the same:only upon sufficient
compressions of the spring. In this case, the body
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has at least one passage formed generally centrally
therethrough, and the passage ha~ walls which collapse
to enable the body to readil~ compress in response to
movement together of the adjacent convolutions upon
limited compressions of the spring. However, the size
of the passage is such that opposite side walls of the
passage move together and engage upon sufficient
compressions of the spring, whereupon the body t~en
resists further movement together of the adjacent
convolutions to stiffen the spring against further
compression.
For any of the above embodiments, the invention
contemplates positioning one or more of the bodies
between one of more adjacent convolutions of the spring,
for example two of the bodies 180 apart between adjacent
convolutions, or three of the bodies 120 apart.
Also contemplated~is a helical embodiment of the body,
which is extendable along and between adjacent
convolutions, the body in this case being generally in
the form of a ramp to have along its length a progressively
increasing or decreasing spaci~g from one of the
convolutions for limited amounts of compression of
the spring.
The foregoing and other objects, advantages and
features of the invention will become apparent upon
a consideration of the following detailed description,
when taken in conjunction with the accompanying
drawings.
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Brief Description of the Drawings
Fig. 1 is an elevation view, partly in cross
section, illustrating a device configured in accordance
with one embodiment of the invention, positioned between
ad]acent convolutions of a coil spring of an automotive
vehicle suspension system;
Fig. 2 is similar to Fig. 1, and illustrates
an embodiment of a resilient material device positioned
between adjacent convolutions of a coil spring;
Fig. 3 is a top plan view,illustrating one
arrangement of devices around a convolution of a
coil spring;
Fig. 4 is a top plan view, and shows another
arrangement of devices around a convolution of a
coil spring;
Fig; S is a top plan view of a generally helical
ernbodiment of device in accordance with a ~urther
embodiment of the invention, showing the same positioned
between adjacent convolutions of a coil spring, and
` Figs. 6-9 illustr~te various additional embodiments
o~ resilient material devices.
De~ailed Description
The present invention provides devices, spacers
or inserts for being mounted between adjacent convolutions
of the coil springs of a suspension systern of an
automotive vehicle. The devices provide progressive
sti~fening or resistance to compression o the springs
with increasing compressions of the springs in response
to roadway bumps, undulations or severe vehicle handling
conditions, but do not impede limited compressions of
the springs under normal, relatively smooth driving
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conditions. In this manner, occupants of the vehicle
are afforded a smooth and comfortable ride under
normal driving conditions, as are usually encountered
a majority o the time, yet progressive stiffening
of the springs occurs under markedly undulating or
severe driving conditions ~or improved roadabilit~,
handling and safety. The spacers are of economical
construction and convenient to install, whereby ~he
same are within the economic reach of and may readily
be installed by an owner of an automobile.
More particularly, with reference to the drawings
there is shown in Fig. l and indicated generally at 10
a device, spacer or insert configured in accordance
with one embodiment of the invention. The insert
comprises a body portion 12 which may be of a rigid
material such as metal, plastics, etc., or o a resilient
material such as ruhber having, for example, a durometer
o~ 40-110. The body portion is positionable between
adjacent convolutions of a coil spring 14 of an automotive
vehicle suspension system, and includes a generally flat
bottom 16~ generally flat sides 18 and a humped or "M"
shaped upper end which defines a pair of h~mped or
elevated portions 20 on opposite sides of a recessed
or concave area 22. A pair of passages 24 through the
body between the bottom and the humps receive stove
bolts 26 having heads 28 and lower thread~ed ends 30
pro~ecting beyond the bottom of the space~.
The device mounts on an acti.ve convolution of the
coil spring, for example one or two convolutions from
the top or bottom of the sprihg~ In this connection,
the body 12 is positioned between adjacent active
convolutions of the spring with the bottom 16 resting
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115~ t~
on the lower convolution and the upper convolution
extending throu~h the concave area 22 between the
humped portions 20. The stove volts 26 extend on
opposite sides of and to a position beneath the lower
convolution, and a plate or bracket 32 receives the
threaded ends 30 of the bolts through apextures at
opposite ends thereof. Lock washers 34 are placed on
the bolts and nuts 36 are then uniformly tightened to
clamp the body and plate together on opposite sides
of the lower convolution and, in the case of a resilient
material insert, until the bottom o the body begins
to visually deform, as at 38.
In mounting the device lO on the vehicle coil
springs 14, with the vehicle at rest a spacing d is
maintained between the upper spring.convolution and
the lowe-E portion o~ the concave area 22, and one or
moxe inserts are ~ounted between each of one or more
adjacent convolutions of each vehicle spring, for
example two or three spacers per adjacent convolutions
on each coil spring as shown in Figs. 3 and 4. For
the case where two spacers are used, as shown in
Fig. 4 the same are advantageously mounted 180 apart,
for example with one being toward and one away from
the wheel of the vehicle àssociated with the particular
spring. Where three spacers are used, as shown in
Fig. 3 the same are advantageously positioned 120
apart, for example with one of the spacers bei.ng
toward the wheel associated with the particular spring.
For the situation where a single spacer is used per
spring, then the same would be located toward the
associated wheel, which would afford increased
vehicle stability during turning or cornering It
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is understood, however, that irrespective of the
number of devices used per coil spring, the invention
contemplates other orientations of the same, and that
if desired more than three spacers may be used per
spring and additional spacers may be mounted between
other adjacent convolutions of the spring.
The spacing d between the insert 10 and the
uppex spring convolution is an important feature of
the invention, and prevents the insert from inter~
fering with limited compressions of the spring. To
this end, the amount of spacing d is selected so
that under average driving conditions on smooth
roadways, as are usually encountered the majority of
the time, the insert does not engage the upper
convolution for limited compressions of the spring and
there~orë does not impede or resist limited compressions
o~ the springs, so that the vehicle's suspension system
operates in its design manner and a smooth and
comfortable ride is aforded to occupants of the
vehicle. At the same time, since the insert normally r
does not simultaneously engage the adjacent spring
convolutions, it does not interfere with the standard
manuactured height of the spring or vehicle. However,
the amount of spacing d is also selected so that ~pon
increased compressions of the spring, as would occur
on very bumpy or undulating roads, when t~rning at
increased speeds, during hard braking or acceleration,
or when the vehicle is heavily laden, the upper
convolution of the spring engages the bottom of the
concave area of the insert, so that further movement
together of the adjacent spring convolutions is
absolutely resisted in the case where the insert is
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of a rigid material, or somewhat compliantly resisted
and limited where the insert is resilient. Thus,
under severe dxiving conditions increased compressions
of the springs are resisted, whereby the stiffness
o the suspension system is increased, as required,
for improved vehicle handling, driveabiliky and
safety.
Referring in particular to Fig. 3, for the case
whexe three inserts 10 are associated with each coil
spring, it has been found through experimentation that
particular improvements in handling are obtained when
the spacing d progressively decreases from insert to
insert around a spring convolution, for example from
the insert lOa to the insert lOb to the insert lOc~
It has also been found through experimentation to be
advantageous to successively decrease the spacing by
fractional amounts, wherein the denominator of the
fraction equals the number of inserts on a single
spring convolution, and the numerator initially equals
the denominator but is increased by "1" for each
successive insert. For example, if the insert lOa is
chosen to have the maximum spacing d, then the spacing
d of the insext lOa is 3/3d, that of the insert lOb is
2~3d, ànd that of the insert lOc is 1/3d. Thus, if
the spacing d of the insert lOa were 1/8", then the
spacing of the insert lOb would be 1/12" and that
of the insert lOc would be 1/24".
For the arrangement in which two inserts are
associated with each coil spring, as shown in Fig. 4,
advantages in suspension improvements have been
obtained when the spacing d of one of the inserts is
greater than that of the other, for example when the
spacing d of the insert lOd is greater than that of
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the insert'lOe. In this case, the denominator of the
fraction would be "2", so that the spacing of the
insert 10e would be 1/2 that of the insert 10d.
To facilitate manufacture o inserts or spacers
which rnay be accommodated to a variety of automotive
vehicles, it is contemplated that the lengths of the
inserts between the bottoms of the concave portions 22
~ and the bottom walls 16 initially be greater than the
spacings between adjacent convolutions of conventional
automotive vehicle coil springs. Thus, to mount the
inserts, a user simply selects the appropriate length
of insert to provide a desired spacing d, and with the
bolts 26 removed cuts off a selected amount o the
bottom of the insert to yield the desired spacing d.
When mounted, because of the spacings d the
inserts do not interfere with limited compressions
of the springs, such as are encountered under average
driving conditions, so that a comfortable and smooth
ride is afforded to occupants of the vehicle. However,
upon occurrence of severe driving conditions and
increased compressions of the coil springs, and in
the case where two or more inserts are used per adjacent
convolutions o the springs, because of the staggered,
ste~pped or progressive spacings d the spacers progressively
engage the adjacent spring convolutions, in accordance
with ~heir associated spacings d, to thereby progressively
increase the spring~s resistance to compression.
Obviously, where'inserts are mounted between two or
more adjacent pairs of convolutions of each coil
spring,'the spacings d may be;selected so that progressive
resistance to compression is offered frorn adjacent
convolutions to adjacent convolutions, from insert to
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insert around each convolution, or in any desired
~ashion. In this manner, the spacers progressivel~
increase the stiffness of the vehicle's s~lspension
system in accordance with the severity of driving
conditions encountered, and automatically compensate
between a soft ride under average driving conditions
and improved handling under severe conditions.
Thus, in use of the inserts of the invention the
suspension system of a conventional automobile operates
in its intended design manner under average driving
conditions, yet assumes the characteristics of a heavy
duty or "high performance" suspension system under
severe driving conditions. To this end, the inserts
enable the suspension system coil springs to variably
resist the momentum of the mass of the vehicle body
and frame upon encountering dips in the road, during
hard braking, acc~leration and cornering, or when the
vehicle is heavily laden, and provide a transitional
rate o spring compression resistance to automaticalIy
compensate for the sprung and unsprung forces exerted r
by the mass o~ the vehicleO Due to the large amount
o~ energy that the springs are able to absorb in use
of the inserts, complete collapse or bottoming o the
springs is prevented, and rebound of the springs after
compression is lessened to an extent that a standard
vehicle's suspension system has capabilities approaching
those of a true pneumatic system, and shock absorbers
and other portions of the suspension system are
subjected to less stress and wear for longer life.
The embodiment of insert:illustrated in Fig. 2
and indicated generally at 100 is similar to that shown
in Fig. 1, except that only a resilient material insert
is contemplated and a hollow chamber 102 is formed
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centrally ~ithin a body portion 104 of the insert
and is vented to atmosphere through a vent 106. As
compared ~ith the device ln Fig. 1, the insert 100
offers a somewhat more variable resistance to spring
compression because of the vented chamber in the
resilient ~ody, the size of the vent being selected
to control movement of air therethrough at a rate
which yields a desired rate of,compressibility.
Fig. 5 shows a top plan view of a generally
helical embodiment of solid or resilient material
insert, indicated generally at 2~0, positioned between
adjacent convolutions of a coil spring 14. The insert
is essentially an elongate and helical arrangement of
the device 10 o Fig. 1, and may be astened to
the lower convolution in a similar ~anner by means of
bolts, only the heads 28 of which'are shown. The
height of the ins`ert is such that a spacing is
normally maintained between an upper surface thereof
and the upper spring convolution, and the insert is-
ramp shaped along its arcuate l~ngth so that the spacing
progrèssiyely decreases from one end of the insert to
the other. An advantage of the helical embodiment
o~ insert is its ability to provide very uniform
progression of increasing spring stiffness, as the
spring is compressed, over a somew~at extended portion
of a convolution. Obvious'ly,',and althougk the helical
spacer is shown extending'over about 240 o the
convolution, it is understood ~hat it could extend
a greater or lesser amount, and that more than one
insert could be used per coil spring.
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Fig. 6 illustrates another embodiment of device
in accordance with the teachings of the invention,
which is indicated generally at 300 and includes a
resilient body portion 302. At each of the upper and
lower ends of the body a pair of humps 304 define a
concave area 306 therebetween~ An advantage of this
embodiment is that the device does not require any
hardware for being mounted on the spring. Simply, the
spacer is positioned between adjacent convolutions of
the spring, with one of the recessed areas 306 receiving
one convolution and the other recessed area receiving
the other convolution. To provide the requisite
"spacing" bet~een the insert and convolutions, so as
not to impede limited compressibility o the spring
under normal driving conditions, a center portion of
the body-.has a passage 308 therethrough. Body walls J
310 on opposite s`ides of the passage move or flex
outwardly upon longitudinal compression of the body,
so that the insert has only very limited resistance to
longitudinal compression until a point is reached
whereat normally separated longitudinal protuberances
312 move together and engage The passage 308, along
with its flexible side walls 310 and the normal spacing-
between the protuberances 312, prevent the insert
from impeding limited compressions of the coil spring
under normal driving conditions, and at the same time
advantageously enable the insert to be manuall~
compressed for easy mounting on the spring. However,
upon the occurrence of severe~driving conditions and
increased compressions of the coil spring, the ends
of the protuberances move together and engage, whereupon
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the insert resists further compression of the spring.
It is understood, of course, that the spacing between
facing ends of the protuberances, when the insert is
mounted on the spring, is equivalent to the spacing d
of the devices shown in Figs. 1 and 2, and that similar
orientations of one or more inserts 300 on a coil
spring are contemplated.
Figs. 7, 8 and 9 illustrate additional embodiments
of resilient material devices which employ the general
concepts and features of the device 300 of Fig. 6.
The devices in Figs. 7 9 are easily mountable on a
coil spring, and by virtue of central passages there-
through do not interfere with limited amounts of spring
compression. However, the passa~es are arranged so
that upon sufficient compression o the spring, opposing
longitudinal ends or sides of the passages move together
and engage, whereupon the devices then resist further
compression o the spring.
While embodiments of the invention have been
described in detail, various modifications and other
embodiments thereof may be devised by one skilled in
the art`without departing from the spirit and scope
of the invention, as defined in the anpended claims.
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