Note: Descriptions are shown in the official language in which they were submitted.
10~i~73-~ -
The present invention relates to means for locating the ,~
end of an elongated member of a vehicle suspension or steering
system. More specifically, the invention provides a spigot assembly
for attaching the knuckle of a vehicle suspension/steering member
to a relatively movable part of the vehicle, and has particular
application to torque rods used in vehicle suspension systems.
Many vehicle suspensions, and steering systems, have
meI~ers which transmit tension or compression between relatively
movable parts. Generally, such members have a knuckle at one end
surrounding a cylindrical bushing which is located by a spigot
or pin connected to the parts to be located, the assembly allowing
pivoting of the member about the pin~or spigot.
As an example, my prior Canadian Patent Number 958,729,
issued December 3, 1974, shows examples of vehicle suspensions
having lower torque rods 5, 105 connected to suspension parts by
various means. An example of a spigot type, or single ended type
connection is shown in Figure 3 of this prior patent, the spigot
being a projecting part of a hollow pin 40 which has a hardened
chrome finish with a smooth machined and polished surface, and which
is held within an accurately machined bore within a suspension
part 22. The pin receives a hollow bushing 42 held within the
knuckle end of a torque rod, which is held on the pin by washer
44 and transverse screw 45. Another arrangement is ~hown in
Figure 9 of this patent, where the end of a torque rod is held in
a clevis in part 103 by a hollow pin 175 which is also hardened
and machined, and with a polished surface, and which fits with-
in accurately machine bores in the sides of the clevis, being
retained in place by screw 176.
These constructions of my~prior patent are relatively
expensive in that they necessitate machining both of the pins and
of the bores into which they fit, since the pins must fit with very
close tolerance within the bores to avoid any slackness. The
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provision of threaded transYerse bores for the retaining screws
also adds to the expense.
The present invention provides an arrangement which is
cheaper in manufacure and assembly than that described in my afore-
said prior patent, and those in general use, and in which parts
can be removed and replaced (for example for the replacement of
bushings) much more quickly than with prior art arrangements.
In accordance with one aspect of the invention, a spigot
assembly for attaching the knuckle of a vehicle suspension/steering
member to a relatively movable part of the vehicle comprises a
spigot part and a cap part, arranged to be held together by bolt
means. The spigot part has a base arranged to be rigidly secured
to the vehicle part and has a generally cylindrical projection and
an annular bearing surface extending outwardly from the foot of
the projection, the projection also having a frusto-conical surface
coaxial with its cylindrical surface and facing axially outwardly
- of the projection. The cap part also has a frusto-conical surface,
which is complementary to and engagable with that of the spigot
part, and the cap part also has an annular bearing surface coaxial
with its frusto-conical surface and which faces the bearing surface
of the spigot part when the two parts have their frusto-conical
surfaces engaged. The spigot and cap parts both have axial bores
for receiving the bolt means, and the parts, when fastened tQ--'
gether, are suitable for locating a bushing held by the knuckle of
the suspension~steering member.
Preferably, the frusto~conical surface of the pro-
jection is concave to provide a recess into which fits the com-
plementary surface of the cap part, the cap part being of
cup-like form so as to have an outwardly facing recess. This
latter recess receives the threaded part, and the nut, of the
nut and bolt assembly which holds the two parts together.
The cap part may have a generally cylindrical surface
between its frusto-conical surface and its annular bearing surface
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106~73~
and which provides a continuation of the cylindrical surface of the'
projection of the spigot part, when the two parts are held together.
With the spigot assembly as described, there is no need
for any surface to be machined. I have found that as cast surfaces
are suitable both for the cylindrical surface of the projection
(and that of the cap when this has a cylindrical surface), which
surface is in contact with the bushing, and as cast surfaces are
also suitable for the engaging frusto-conical surfaces of the two
parts. The conical nature of these surfaces insures adequate
co-axial alignment of the two parts even with irregularites of
casting, and likewise such irregularities do not cause any slackness
in the assembly. Thus, all machining co~ts are avoided. Further-
more, the parts are very simple to assemble and disassemble,-as
when it is required to replace a torque rod or torque rod bushing.
The invention will be described in more detail with
reference to the accompanying drawings, in which:-
Figure 1 shows a diagrammatic plan view of the vehiclesuspension using the spigot assembly of this invention,
Figure 2 shows a detail of a portion of Figure 1 in which
a part of the spigot assembly and associated end of the torque rod
are sectioned,
Figure 3 shows a partial view of the underside of the
spigot part as seen in the direction A of Figure 2, and
Figure 4 shows a view on 4-4 of Figure 2 but showing
the spigot part on~y with the nut and bolt, the cap, and the torque
rod removed.
Figure 1 shows certain components of a tandem axle truck
suspension basically similar to that of my Canadian Patent Number
782,947, issued April 16, 1968, and especially shows the parts
which are illustrated in full in Figures 1 and 3 of that patent.
In this suspension, each axle 10 is located relative to side chassis
members 12 by a ~-shaped arrangement of upper torque rods 14, and
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by a pair of longitudinal lower torque rods which are not shown ~-
in Figure 1. Also not ~hown in Figure 1 are rubber springs
which support the chassis members above the axles, via long-
itudinal beams which have their ends supported by the ends of
the axles. This type of suspension is however only described
by way of being a typical environment for the use of torque~ ;
rods 14, or like members, which may be found in many suspension
and steering systems.
The rods 14 have at each end an enlarged eye or
knuckle 20, in the form of a short cylinder transverse to the
rod and having a bore which is of convergent-divergent form
as shown in Figure 2 and which is cast on the end of the rod
and which requires no machining. Into this bore is inserted a
resilient elastomeric bushing 22, preferably of rubber, hàving
an outer shape conforming to that of the transverse bore, and
having a parallel sided inner surface. This inner surface is
located by a spigot assembly 24, three of which identical
assemblies are illustrated in Figure 1, and one of which is
shown in detail in Figure 2.
Referring to Figure 2, the spigot assembly is shown
as including,basically, a spigot part 26, a cap part 28, and
bolt means 30 which hold the two parts together.
The spigot part 26 is a casting which has a flat
base 32 which, as shown in Figure 4, has four holes whereby
it is attached to the chassis member 12 by bolts 33. Project-
ing upwardly from the base is a hollow angled support 34 having
part cylindrical walls 36 which surround an axis which is off-
set at 28 from the normal to the base. The top of the supp-
ort 34 is solid with a generally cylindrical projection 38,
the walls of which are joined by a radius at the foot of the
projection to an annular bearing surface 40 which surrounds the
foot of the projection. The projection extends for a length
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slightly more than half the length of the bushing 22 of a torque ,~
rod end received thereon, and has at its outer end an axial recess
largely defined by a frusto-conical surface 44 which diverges
from the base of the recess and from an axial bore 46 within the
projection. The bore 46 is designed to take a bolt 30', and the
underside of the support 34 is provided with a triangular recess
34a, the form of which is shown in Figure 3, ~nd ~he sides of
which are designed to prevent rotation of the hexaganol head 30a
of the bolt. The bolt is placed within the bore, as shown, before
the part 26 is secured to a chassis member or like partj and is
retained in the position shown by means of a locking ring 31
which engages in the recess of the projection near to its bottom.
The cap part 28 is of hollow, cup-like form, having a
projection with an outwardly facing frusto-conical surface engaging
the surface 44 of the recess in the spigot part. The cap part
also has a generally cylindrical surface 60 which forms a con-
tinuation of the surface of the projection 38, although being
of slightly less length. This cylindrical surface is joined by
a radius to an annular bearing surface 62 which faces the surface
40. The hollow interior of the cap part receives the threaded
portion of bolt 30~ and has a flat bottom area 64 engaged by a
nut 30b on the bolt.
During assembly of a suspension as illustrated in Figure
1, the spigot part is firstly fitted with the bolt 30r and the
retaining ring 31, and is then bolted onto the respective chassis
member 12, The spi~ot-parts may also be made suitable for welding
onto a chassis or other part. A torque rod 14 is then located on
the projection of the spigot, as shown in Figure 2, and the cap
part 28 then placed in position also as shown in Figure 2. The
nut 30b is then put in place and tightened until the complementary
frusto-conical surfaces of the spigot and cap parts are drawn
tightly together. Although both the spigot and cap parts are in
as-cast condition, so that the frusto-conical surfaces do not
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mate exactly, neyerthele~s it ha~ been found that they mate
sufficiently ~ell for the t~o parts to be substantially held in
alignment.
The rubber bushing 22 is dimensioned so that when held
by the torque rod end and axially uncompressed it can slide easily
onto the spigot, and the cap can be easily inserted into it.
However, when the spigot and cap are drawn together by nut 30b,
the bushing 22 is axially compressed between the bearing surfaces
40 and 62 of the spigot and cap parts, and is thus also caused
to be compressed between the cylindrical surface of the spigot
and the internal surface of knuck~e 20, to such a degree that
the bushing does not normally slide relative to these surfaces,
being sufficiently deformable to allow the normal movements in
the suspension without sliding. However, unusual movements will
allow the rubber to slip until it reaches a neutral position.
For replacement of the bushings of a torque rod, all
that is required is the removal of nuts 30b holding the cap parts
at each end of the torque rod, whereupon the rod and caps are
removed, and the rod replaced with a new rod or with the same
rod fitted with new bushings. There is sufficient spring in
the rubber bushing for the spigot assembly to be tightened up
completely at one end, and the other end of the torque rod can
still be sprung onto its spigot. Preferably, however, the ends
of the torque rod are placed on the respective spigots before
any tightening takes place.
It will be seen that the spigot assembly can be used
in many different situations. Figure 1, in addition to showing
the spigot assembly 24 attached to the chassis member 12, shows
identical spigot assemblies which are attached to a vertical
plate 70 projecting upwardly from the axle 10 and braced by
gussets 72. Similar spigot assemblies can be used for locating
the lower torque rods, although of course in this case the
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support 34 would haye its axi~ nox~al to the base 32, rather
th~n ~t an obllgue angle.
