Note: Descriptions are shown in the official language in which they were submitted.
1069139
BACKGROUND OF THE INVENTION
It has heretofore been the practice in the construction of
vehicular shock absorbers of the type including a reciprocable piston
located within a fluid chamber and provided with valve means for
controlling the fluid flow through selected fluid ports, to operative- .
ly connect the piston assembly to one end of an associated piston rod
which projects coaxially outwardly from the shock absorber and is
connected, either directly or indirectly, to a portion of a vehicle
æ
13~
suspension. Various means have been utilized in the prior art for
operatively securing the piston assembly to the piston rod, one of
the most common of which consists of providing some type of a thread-
ed element, such as a nut or the like, and threadably connecting
said element to an externally threaded portion formed on the ad-
jacent end of the associated piston rod. One such example of this
prior art construction is shown in United States Letters Patent No.
3,757,910, dated September 11, 1973, and assigned to the assignee
of this application. The aforesaid procedure of operatively con-
necting the piston assembly to the piston rod by means of a thread-
ed element or nut has been found to be objectionable for a number
of reasons, not the least of which is the cost and time required
in machining the nut and associated piston rod.
Various solutions have been proposed to such prior art
designs, including the idea of connecting the piston assembly to
the associated piston rod by means of a welding operation, such as
shown in United States Patent No. 3~724,615, issued April 3, 1973,
wherein the piston body is connected by means of a weld operation
to the adjacent end of the associated piston. This method of
assembly, however, has not been entirely satisfactory due to the
fact that it requires extremely costly equipment and proper quality
control can be difficult to maintain. One more serious problem
results from the aforesaid type of construction and that resides in
the frequent necessity of providing some type of a sliding seal
around the outer periphery of the piston body to assure that a
fluid tight joint is provided between the outer
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1069~39
poriphery of the piston and the inner periphery of the adjacent
cylinder wall, whereby to assure against fluid by-passing the
piston instead of flowing through the valve ports normally provided
therein. Such ancillary fluid sealing means have been required, at
least in part, due to the eccentricity or "radial runout" between
the axis of the piston rod and piston body which, in many instances,
may be in the magnitude of several thousands of an inch. Moreover,
while the aforesaid fluid seals have been found to be at least a
satisfactory solution to such eccentricity between the piston and
piston rod, in certain circumstances, the seals themselves become
irregularly worn, thus permitting fluid by-passing and premature
failure of the shock absorber.
A related short-coming of certain prior art designs, ~-
such as that shown in United States Patent No. 3,187,847,
results when the piston assembly is connected to the associated
piston rod by means of a cold or hot "upsetting" process which
results in substantial molecular distortion or alteration of the
piston rod which may, under certain circumstances, have an adverse
effect on the structural integrity of the material interconnecting
the piston and piston rod, with the result that the connection falls
short of the requisite tensile strength specifications in the
industry.
The present invention is directed toward a new and im-
proved shock absorber construction and method and apparatus for
assembling the same which overcomes the various shortcomings of
prior art designs. In particular, the present invention is directed
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1069139
toward a new piston-piston rod assembly wherein the piston rod
is operatively connected to the piston assembly in a manner such
that an extremely strong joint is provide therebetween without
any sacrifice in the desired concentricity between the piston body
and piston rod. The connection is achieved by means of inserting
a tool into the valve chamber of the piston from the opposite side
thereof from which the piston rod extends and operatively moving
the tool in a preselected manner. Specifically, the tool is moved
in a generally cycloidal path such that an overlapping rosette type
pattern is formed. By so moving the tool, small portions of the
material from which the piston rod is fabricated is moved radially
outwardly to form an~enlarged diameter head, with the material
moving so gradually that there is virtually no molecular alteration
destruction of the piston rod material. Accordingly, the unit
strength of the resultant joint is extremely high. One particular
advantage of the invention resides in the fact that the tool may
be inserted interiorly of the valve chamber to a position where
the tool may contact the end of the piston rod without in any way
interferring with the fixture of apparatus which functions to coax-
ially support the piston and piston rod during assembly thereof.
Accordingly, the highest concentricity standards may be readily
achieved, as compared to prior art desigs. An additional fea-
ture of the present invention resides in the fact that by properly
designing the assembly tooling or fixtures, the piston and piston
rod will be self-centering or aligning during the fastening or
1069139
securing operation, thus assuring concentricity of the resultant
assembly. Accordingly, the present invention provides a piston-
piston rod assembly which is of substantially higher quality than
prior art designs and yet may be manufactured at a considerable
savings in capital equipment.
SUMMARY OF THE INVENTION
This invention relates generally to hydraulic shock
absorbers and, more particularly, to a new and improved piston-
piston rod assembly for use in such shock absorbers.
It is accordingly a general object of the present in-
vention to provide a new and improved piston-piston rod assembly.
It is another object of the present invention to provide
a new and improved means for operatively connecting the piston
assembly and piston rod of a hydraulic shock absorber wherein
an extremely strong joint is provided therebetween.
It is another object of the present invention to provide
a new and improved piston-piston rod assembly which provides
for maximum concentricity between the piston and piston rod
without any sacrifice in the unit strength of the joint connecting
these components.
It is still another object of the present invention to
provide a new and improved apparatus for securing piston and
piston rods in their assembled orientation during the performance
of an assembly operation thereon.
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~ 1 3 9
It is yet another object of the present invention to
provide a new and improved connecting means for operatively
connecting a piston and an associated piston rod wherein the
molecular structure of the connecting means is in no way
altered or distorted, as is the case with prior known methods
consisting of hot or cold upsetting, stamping or the like.
Thus, one aspect of the present invention is
broadly defined as a piston and piston rod assembly comprising,
a piston including a piston body member having a skirt portion
defining an open-sided valve chamber and terminating at one
end thereof in an imaginary plane arranged perpendicular to the
axis of the assembly, the piston body member being formed with
a central bore including a cylindrical outer end section and a
frusto-conical inner end section having a minor diameter portion
of approximately the same cross-sectional size as the cylindrical
end section and a major diameter portion of larger cross-sectional
size than the cylindrical end section, a piston rod arranged
generally coaxially of the piston, and means operatively connect-
ing one end of the piston rod member to the piston, the last
mentioned means including one end of the piston rod projecting
through an opening in the body member and having the terminal
end portion thereof deformed by a process wherein the terminal
end portion is engaged by a tool moving along a generally
cycloidal overlapping rossette path defining a pair of cones,
the apexes of which intersect along an imaginary plane extending
parallel to the.first mentioned plane and located axially between
the first mentioned plane and one end of the piston rod, whereby
to deform the material of the piston rod to occupy substantially
the entire volume of the inner end section of the bore and form
db/ ~ -6-
'13-'~. A
.. . . - . . . . . . ~: . . , -
.. - . . . .: . , . . . . : : -
... ~ .. . , . . - . -
- . . ~ .
.. . . . . . - . ..
.. : .............. ..
.... . . . . .
--` 1069139
an enlarged diameter head portion facing the open side of the
chamber and having a substantially non-distorted molecular
structure, the area of deformation of the end portion being
greater than the area of the cylindrical inner end of the bore,
and the area of the open side of the chamber being at least as
great as the area generated by the portion of the tool that is
' aligned with the open side of the body when the tool moves along
the path during the deforming process.
Another aspect of the present invention is broadly
defined cls a method of assembling a piston and piston rod, the
steps of which include, supporting the piston and piston rod
in a position wherein one end of the piston rod is received
within an opening in the piston, engaging a tool with one end
of the piston rod, and causing the tool to move along a generally
cycloidal overlapping rossette path defining a pair of cones,
- the apexes of which intersect along an imaginary plane arranged
perpendicular to the axis of the piston and piston rod whereby
to deform the material of the piston rod to occupy substantially
i the entire volume of the opening in the piston and form an
enlarged diameter head portion having a substantially non-
distorted molecular structure.
; Other objects and advantages of the present invention
will become apparent with the following detailed description
I taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE D~AWINGS
Figure 1 is an elevated perspective view, partially
I broken away, of a vehicular shock absorber embodying the
principles of the present invention;
Figure 2 is an exploded assembly view of the
db/- ~ -6a-
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1069139
piston assembly incorporating the shock absorber shown in
Figure l;
Figure 3 is an enlarged cross-sectional view of the
piston assembly shown in Figure l;
Figure 4 is an elevated perspective view of an
~ exemplary embodiment of an apparatus for practicing the princi-
: ples of the present invention and in particular, for securing
the piston assembly to the associated piston rod of the shock
absorber shown in Figure l;
Figure 5 is a longitudinal side elevational view of
an exemplary embodiment of the mounting fixture operatively
associated with the apparatus shown in Figure 4;
:,
,,
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:
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:
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-: , . . . . - . : : . .
. . . - , : -
``-` 1069139
Figure 6 is a top elevational view of the fixture shown
in Figure 4;
Figure 7 is an enlarged cross-sectional view of the
fixture shown in Figure 5; and
Figure 8 is an elevated perspective view, partially
broken away and partially in schematic, of the method of secur- :
ing the piston and piston rod incorporated in the shock absorber
shown in Figure 1.
DETAILED DESCRIPTION OF THE INVENTION
Referring now in detail to the drawings and in particu-
lar to Fig. 1 thereof, a vehicular shock absorber is shown as be-
ing generally designated by the numeral 10 and including upper and
lower end fittings 12 and 14, respectively, which are adapted to be
operatively secured to the sprung and unsprung portions of an asso-
ciated automotive vehicle or the like. The shock absorber 10 in-
cludes a tubular or cylindrical pressure cylinder 16 which defines
an interior fluid chamber 18. Disposed within the chamber 18 is
a reciprocable piston assembly, generally designated by the numeral
20, which is operatively secured to a piston rod 22 that is disposed
coaxially within the cylinder 16. The upper end of the piston rod
22 extends through a combination rod guide and seal assembly 24
which closes the upper end of the cylinder 16, as illustrated. Dis-
posed around the exterior of the pressure cylinder 16 and arranged
generally coaxially thereof is a reserve tube 26 which defines an
annular fluid reservoir 28 with the outer periphery of the pressure
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1069139
,.
cylinder 16. The reservoir 28 is adapted to contain a supply of
hydraulic fluid which functions as a damping medium for recipro-
cal movement of the piston assembly 20 within the chamber 18 and
means in the form of a suitable anti-acration helical baffle 30
is provided within the reservoir 28 for purposes well known in
the art. The lower end of the shock absorber 10 is provided with
a lower end cap 32 which functions to operatively carry or support
the lower end fitting 14, as illustrated, and means in the form
of a suitable base valve assembly 34 is disposed interiorly of the
end cap 32 and functions to operatively control the flow of fluid
between the chamber 18 and the reservoir 28. The upper end of the
shock absorber 10 is provided with an upper end cap 3~ which.is fix-
edly secured to the reservoir tube 26 and is formed with a central
opening 38 through which the upper end of the piston rod 22 extends.
A suitable dust shield 40 is shown upon the upper end of the piston
rod and includes a generally cylindrical portion 42 extending co-
axially around the outer periphery of the reserve tube 26, and a
generally cup-shaped securing portion 44 which is attached to the
upper end of the piston rod 22 directly adjacent the upper end
fi*ting 12.
: Referring now in detail to the construction of the piston
assembly 20, as best seen in Figures 2 and 3, the assembly 20 in-
cludes a generally cup-shaped piston body 50 which is preferably,
although not necessarily, fabricated of a high density sintered ;
metal. Alternatively, the body could be formed by a conventional
cold upsetting process. The body 50 includes a base portion 52
and a generally downwardly extending peripheral skirt portion 54
which defines with the base portion 52 an
-` 1069139
annular valve cavity 56. The base portion 52 is formed with a
central annular opening 58 which cooperates with a lower end -
section 60 of the piston rod 22 in operatively securing the
piston assembly 20 thereto, as will hereinafter be described. The
base portion 52 of the piston body 50 is also formed with a
plurality of equally circumferentially spaced axial flow ports
which are spaced radially outwardly from the central opening 58
and are generally designated by the numeral 62. Disposed
interiorly of the peripheral skirt 54 is a radially inwardly
extending annularshoulder64 against which an annular valve plate,
generally designated by the numberal 66, is operatively disposed.
The valve plate 66 is formed with a central opening 68 and the upper
side thereof is formed with a pair of radially spaced concentrically
oriented inner and outer annular valve seats 70 and 72, respectively.
Extending axially through the valve plate 66 at a position between
the valve seats 70, 72 is a plurality of circumferentially spaced
flow ports, generally designated 74. The flow ports 74 are normally
closed by an annular valve disk 76 which is urged into scaling engage-
ment with the upper ends of valve seats 70, 72 by means of an
annular valve spring, generally designated by the numeral 80.
The under or lower side of the valve plate 66 is formed
with a central counter bore 82 which is coaxially arranged relative
to the central opening 68 and is adapted to nestingly receive an
annular valve seat member 84. The member 84 is urged upwardly
into scaling engagement with a flat radially disposed surface
86 within the counter bore 82 by means of a helical coil spring,
generally designated by the numeral 88. As illustrated,
the upper end of` the spring 88 bears against
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106~139
the underside of the member 84, while the lower or opposite end of
the spring 88 is operatively supported upon or within a spring cage,
generally designated by the numeral 90. The cage 90 is of a general-
ly cup-shaped configuration and is formed with a lower central open-
ing 92and with a plurality of peripheral or side openings 94. The
upper end of the cage 90 is formed with a radially outwardly extend-
ing shoulder portion 96 which is adapted to be fixedly secured along
with the valve plate 76 by means of a lower crimped flange portion
98 formed at the distal or terminal end of the peripheral skirt
portion 54.
As will be appreciated by those skilled in the art, during
a compression stroke of the shock absorber 10 wherein the piston
assembly 20 moves downwardly within the chamber 18, hydraulic
fluid will flow through the spring cage 90 and thereafter through
the plurality of ports 74, thereby unseating the valve disk 76 from
the valve seats 70, 72. Conversely, during a rebound stroke wherein
the piston assembly 20 and piston rod 22 move upwardly within the
chamber 18, fluid will flow downwardly through the flow ports 62,
through a central opening 78 formed in the valve disk 76 and there-
after through the central opening 68 of the valve plate 66. This
fluid will then effect unseating of the member 84 against the
resistance of the spring 88, from where~the fluid will flow
through the spring cage 90 into the lower end of the chamber 18.
In accordance with the principles of the present invention,
the end portion 60 of the piston rod 22 is adapted to be operatively
connected to the piston body 50 in a new and unique way so as to
provide for extreme concentricity between the axis of the
piston rod 22 and the
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1069139
piston assembly 20 without any sacrifice in the tensile strength
at the interconnected portions thereof. Toward this end, the actual
connecting means utilized in securing the piston body 50 to the
piston rod 22 is in the form of a rivet-like joint which is produced
by selectively and progressively moving a tool against the end
portion 60 and in particular, toward and into engagement with the
end of the reduced diameter portion 100 of the rod 22 which extends
through the central opening 58 in the piston body 50. In the
manner best shown in Figure 8, the tool, herein designated by the
indicia T is adapted to be moved in a generally cycloidal manner
along or in an overlapping rosette pattern and the force applied
by the tool to the end portion 100 of the piston rod 22 is such
that the material of the piston rod 22 is stressed beyond its
compressive unit strength, yet short of its ultimate strength.
The material of the rod 22 is thereby deformed progressively as
a result of the cycloidal movement of the tool T so that it flows
into the shape best shown in Figure 3 and hereinafter to be des-
cribed without any heat buildup, change in molecular structure
or damage to any protective coating which may have previously
been applied to the piston rod 22. By properly controlling the
cycloidal pattern and force that the tool exerts against the
rod 22, only a minute quantity of material is displaced during
each revolution or orbit of the tool T, and consequently, a
smooth flow or wave of material is formed ahead of the orbiting :
tool during its downward stroke. The action of the tool T takes
place in a three dimensional working cycle: (a) radially outwardly,
(b) radially inwardly, and (c) overlapping tangentially, with only
a small portion of the tool T actually contacting the end
of the piston rod 22 which
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1069~3~
results in the aforementioned flow of material without the usual
molecular destruction and cracking of material as occurs during
cold or hot upsetting processes known in the prior art and causes
severe molecular dist tion and compression of the metal fibers.
It is preferred that there is no rotation between the tool T
relative to the end portion lO0 of the piston rod, but instead, that
the tool T exert a gentle but firm force against the material con-
stituting the end portion 100. By precisely controlling the pressure
applied by the tool T, virtually noiseless production is achieved,
as compared with normal riveting, stamping, upsetting processes and
the like, thus complying with Federal Safety Health Laws. A
typical operational cycle involves the tool T making approximately
elevent loops during its cycloid movement, with the loops of the
moving tool overlapping each other to provide total coverage, thus
insuring a strong uniform grain structure without any reduction
of the tensile strength of the piston rod 22 below its tensile
yield. ;
In a preferred construction of the present invention, the
end portion 100 is defined by the generally flat radially disposed
surface or shoulder 102 on the piston rod 22, which surface 22 is
adapted to be engaged with a flat radially extending surface 104
formed on the upper or outer end of the piston body 50. The inner
end of the-ope-ning 58 is!formed with a generally conically shaped
counter bore or chamfer section 106 the peripheral wall of which
is at an approximately 30 angle relative to the longitudinal
axis of the piston body 50. Accordingly, during the securing
operation, the details of which will hereinafter be described,
the end portion lO0 of the piston rod 22 is formed with a head
section 108 consisting of a generally frusto-conical portion 110
and a rounded
-12- -
. - ~069~39
or circular terminal end portion 112 and the maximum diameter of
which is larger than the diameter of the opening 58, thus assur-
ing for a strong positive connection between the rod 22 and the
piston body SO. One feature of the present invention resides in
the fact that the frusto-conical shape of the counter bore 106
and piston rod portion 110 results in the self-centering or
automatic coaxial alignment between the piston rod 22 and piston
body 50 as the two components are secured to one another.
Referring now to Figure 4, an examplary embodiment of a
machine or apparatus for performing the operation to secure the
piston body 50 to the piston rod 22 is generally designated by the
numeral 111. The machine 111 comprises a bed or support platform
112 about which an operating head 114 is supported by means of a
.
suitable pivotal support pedestal or the like 116. Disposed
adjacent the bed 112 is a work stock fixture, generally designated
by the numeral 118, which is adapted to operatively support a piston
rod 22 and piston body 50 as these components are being operatively
secured to one another. It will be noted that the fixture 118 is
illustrated merely for purposes of example and that the fixture 118
is illustrated merely for purposes of example and that the present
invention is not in any way intended to be limited to the specific
configuration of the fixture 118 disclosed herein. The operating
head 114 includes a tool chuck or holder 120 which is adapted to
operatively support the tool T hereinabove described, with means in
the form of an operating control box or the like 112 being located
adjacent the head for effecting energization of the chuck 120 in a
manner well known in the art.
With reference now to the construction and operation of
the fixture 118, as best seen in Figures 4 through 7, the fixture 118
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1069139
includes a generally horizontally disposed support plate 124 which
is fixedly secured to the bed or platform 112. Disposed above and
supported upon the plate 124 is a pair of locking jaws 126 and 128
which are adapted to nestingly receive and operatively support a
piston body, such as the body 50, and the upper end of a piston rod,
such as the piston rod 22, during the time the operating head 114
performs the aforedescribed operation upon the end portion 100 of
the piston rod 22 in order to effect securing thereof to the piston
body 50. As best seen in Figure 7, the locking jaws 126, 128 define
; confronting semicircular recesses 130 and 132, respectively. The
recesses 130, 132 are formed with relatively enlarged diameter upper
portions 134 and 136, respectively, and with relatively smaller dia-
meter lower portions 138 and 140, respectively. When the jaws 126,
128 are oriented in the position shown in the drawings, a typical
piston body 50 is adapted to be received between and supported with-
in the upper portions 134, 136 thereof, while the upper end of a
-piston rod 22 is adapted to be operatively supported and secured
within the lower portions 138, 140. The jaw 126 is adapted to be
fixedly secured to the plate 124 by means of a support bracket or
the like 142 which is secured via suitable screws, bolts or the like
144 to the jaw 126. The bracket 142 is in turn secured
via suitable bolts or the like 146 to the upper side of the plate
124, as illustrated.
Although the locking jaw 126 is fixedly secured to the
plate 124, the jaw 128 associated therewith is adapted to be moved
toward and away from the jaw 126 in order to lockingly secure a
piston body 50 and piston rod 22 within the fixture 118. According-
ly, the locking
. .. : , - . :
1069~3~3
jaw 128 is operatively secured to a suitable support bracket 148 by
means of screws, bolts or the like 149, as shown in Figure 7. The
bracket 148 and hence the locking jaw 128 secured thereto is adapted
to be moved toward and away from the jaw 126 in a manner herein-
after to be described and means for guiding the support bracket 148
for such movement is provided by a pair of spaced parallel guideways
150 and 152 which are secured to the upper side of the plate 124 by
means of suitable screws, bolts or the like 154. The support bracket
148 and locking jaw 128 secured thereto is movable longitudinally
within the guideways 150, 152 by means of an elongated manually
graspable or engageable locking arm 156 one end of which is connected
via pivot pins 158 and 160, and a pivotal linkage 162 to a pivot
clevis 164 operatively secured upon the upper side of the plate 124
by means of suitable screws, bolts or the like 166. The inner or ::
rightwardly end of the locking arm 156, herein identified by the
numeral 168, is formed with a transversely extending bore 169
through which a transversely extending cross pin 170 extends. The :
cross pin 170 also extends through aligned apertures 171 in a reci-
procable piston or plunger 172 that is nestingly received within a
recess or blind bore 174 formed in the support bracket 148. Dis-
posed interjacent the inner end of the plunger 172 and the innermost
portion of the bore 174 is a compression spring 176 which functions
in a manner hereinafter to be described. The opposite ends of the
cross pin 170 extend through elongated apertures 178 and 180 formed
in the bracket 148 on opposite sides of the blind bore 174 and are
intended to provide for limited longitudinal sliding movement of the
plunger 172 within the bore 174. -
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- 1069139
The provision of the linkage 16Z and sliding movement of the plunger
172 within the support bracket 138 provides for an over center move-
ment of the locking arm 156 so as to effect lockingly securing a pis
ton body 50 and piston rod 22 between the iaws 126, 128. More
particularly, assuming that the arm 156 is normally disposed in the
phantom line position shown in Figure 5, the jaws 126, 128 are
spaced sufficiently apart to permit a piston rod 22 to be inserted
between the lower recessed portions 138, 140, while a piston body
50 may be deposited between the upper recessed portions 134, 136.
Thereafter, the arm 156 is pivotally biased from the phantom line
po~ition shown in Figure S to the solid line position shown in this
figure, whereupon the support bracket 148 and locking jaw 128
supported thereon will move toward the right until such time as
the arm 156 is lockingly secured in the position shown in solid
lines in Figure 5. With the arm 156 in this position, the plunger
172 will, via the compressed coil spring 176, exert a rightwardly ~ .
directed force against the bracket 148 and hence against the jaw
128. The dimensions of the recesses 130, 132 are such that when the
arm 156 is disposed in its locked downward position, the piston body
50 and piston rod 22 will be lockingly secured therewithin so that
there wili be no movement therebetween or relative to the head 112
of the apparatus 111 during the securing operation.
With reference again to Figure 5, extending downwardly
from the underside of the plate 124 is a generally vertically
disposed support plate 182. The upper end of the plate 182 is
secured via an attachment section 184 and suitable screws, bolts
or the like 186 to the underside of the plate 124 at a position
generally beneath the jaws.
16
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- ~069139
126, 128. The plate 182 is formed with a plurality of pairs of
generally horizontally aligned, vertically spaced apertures,
generally designated by the numeral 188, to which a support block
190 is adap*ed to be selectively secured, as by suitable screws,
bolts or the like 192. The support block 190 is formed with a
generally centrally located vertically disposed threaded opening
194 within which an adjustment member 196 is threadably received.
The member 196 is located in vertical alignment with the center
of the recesses 130, 132 and the upper end thereof defines a support
surface 198 upon which the lower end of a piston rod 22 is adapted
to be supported during the operation connecting the opposite or
upper end of the rod 22 to an associated piston body 50. Accordingly,
the member 96 may be vertically adjusted within the block 190 and the
block 190 may in turn be vertically adjusted by being secured to
selected of the pairs of apertures 188 so that the surface 190 is
properly and vertically spaced relative to the jaws 126, 128 such
that when a piston rod 22 is dropped downwardly therebetween, the
lower end of the rod 22 will rest upon a surface 198, while the
upper end thereof will be properly vertically located relative to
the piston body 50 mounted within the upper recessed portions 134,
136 such that the surface 102 on the piston rod 22 is engaged with
the surface 104 on the piston body.
Referring now in detail to the overall method of operatively
securing the piston body 50 to the associated piston rod 22, assuming
that the locking arm 156 is disposed in its upwardly or unlocked
position shown in phantom lines in Figure 5, the piston rod 22 is
initially inserted downwardly between the jaws 126, 128 to a position
wherein the lower
- 1069~39
end thereof is supported upon the surface 198 of the member 196.
Thereafter, the piston body 50 is dropped downwardly within the
recesses 130, 132 at a position wherein the valve cavity 56 is facing
upwardly. As previously mentioned, when the body 50 and piston rod
2 are thus positioned, the surfaces 102 and 104 are contiguously
engaged with one another. Thereafter, the locking arm 56 is pivoted
from the phantom line position shown in Figure 5 to the solid line
position shown in this figure, thereby lockingly securing the piston
body 50 and piston rod 22 relative to machine ll. The operating
head 114 of the machine lll is thereafter properly positioned by
suitable rotation upon the pedestal 116 such that the axis of the ~;
chuck 120 is properly aligned with the axis of the body 50 and
piston rod 22, after which time the head 114 may be energized.
When this occurs, the tool T will perform the deforming action
hereinabove described as a result of its cycloidal movement,
whereupon the end portion 100 of the piston rod 22 will be de-
formed in a manner such that the frusto-conical and rounded head
portions llO and 112 will be formed, as best seen in Figure 3,
thereby operatively securing the body 50 to the piston rod 22.
After the securing operation has thus been completed, the locking
arm 156 may be pivoted upwardly or in a generally clockwise direction
in Figure 5, thereby releasing the unitized assembly of the body 50 -
and piston rod 22 from within the jaws 126, 128. The remainder of
the piston components may thereafter be operatively mounted within
the valve cavity 56 by properly inserting the valve disk 76, valve
spring 80, valve plate 66, valve member 84, spring 88, and finally
the spring cage 90 may be operatively secured to the body 50 by
properly crimping the
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`-` 1069~39
flange portion 98. After this has been completed, the entire
assembly of the piston 20 and piston rod 22 may be assembled
into the shock absorber 10 for completion of the assembly process.
- While it will be apparent that the preferred embodiment
herein illustrated is well calculated to fulfill the objects above
stated, it will be appreciated that the present invention is sus-
ceptible to modification, variation and change without departing
; from the scope of the invention.
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