Note: Descriptions are shown in the official language in which they were submitted.
2113937
METHOD AND APPARATUS FOR FRACTURING CONNECTING RODS
AND THE LIKE
This invention relates to the fracture separation, into a bearing cap and a
con,~c~ g rod, of an integral preform, while ensuring that the separated pieces
will be capable of re-lmifi~ation, in a high production ellvirolllnent.
BACKGROUND OF THIS INVENTION
Numerous methods have been employed to sepalal~ conn~octing rod
preforms by fracturing, both in laboratory and production enviro~ lenls. These
include cryogenic cooling or electron beam exposure to embrittle the fracture area,
fractllring by wedge act l~tion of an exp~n-lin~ mandrel, and linear opposing
pulling forces to separate the bearing cap from the col~le~;lillg rod preform. The
following patents are ~eplesell~live of the prior art:
U.S. patent No. 4,569,109, issued on February 11, 1986;
U.S. patent No. 4,768,694, issued on September 6, 1988;
U.S. patent No. 4,993,134, issued on February 19, 1991.
Despite these prior developments, certain elements vital to fracture
sepalation continue to have the gledte~l inflllPnre on the quality of the fini~h~d
conn~-cting rod. Two of these elements are:
(a) achieving ~imlllt~n~ous fMcture along the cracking plane of both
legs of the conn~cting rod. Failure to achieve simlllt~nPous fracture
is likely to result in plastic deformation of the crank bore and inhibit
re-mating of the two parts;
(b) m~int~inin~ positive control over the position of the separated
bearing cap and conl~ rod body, to ensure accurate micro-
~lignm~l t during re-mating. Failure to do this may negate the
inherent advantages of fracture separation.
GENERAL DESCRIPTION OF THIS INVENTION
The present invention provides an appalalus and a process for
accomplishing the fracture sep~àlion, into a bearing cap and a conllPclil-g rod, of
an integral plefoll,l, the latter being composed of powdered metal, cast iron,
forged steel, alll.l,i,,.llll or any other material suitable for use as a connecting rod.
The process of this invention is con-lucted under ambient conditions and requires
211~937
no prior embrittlement of the prefo~ , as called for by earlier developments
ili7ing cryogenic chilling or electron beam hardening.
However, a stress-riser is required to control the location of fracture
initiation (i.e. the location of the joint line). The stress-riser may be provided in a
5 prior process by way of (a) V-notch broaching or other equivalent machining
means, (b) laser etching, or (c) prefolllling a stress-riser in the "green" preform
prior to firing (baking) and forging.
The present process utilizes a work-holding fixture which retains and
locates the co~ g rod preform with respect to its m~nllf~ctllring datum
10 fealul~s. The mechanism includes a dual slide ram coupled to a unilateral wedge
interposed between a two-piece lllalldl._l which, when activated, effects the fracture
separation of the preform into a bearing cap and the col~l~ecling rod.
A further aspect of this process is the ability of the work-holding fixture to
locate the pre-sepdldted conn~cting rod preform on the m~mlf~rtllring datum
15 fcaLules, and to m~int~in this location throughout separation and re-mating. This
goal is achieved by constructing the work-holding feature on a precision slide. A
lower portion of the work-holding fixture, which rigidly secures the conn~cting
rod body, is affixed to the slide and restrains the conn~cting rod against any
movement. The upper portion of the work-holding fixture, which locates and
20 retains the bearing cap of the ultim~t~ connPcting rod, is affixed to a slide saddle
movable on the precision slide.
This ~l~lgclllclll allows the bearing cap to move independently of the
col-nPcli,~g rod body during separation, while co..l;..~ g to m~int~in its precision
location with respect to the conn~ctin~ rod body. The arrangement of the present25 invention further eli...i~-~t~s any tendency for the bearing cap to rotate during
scpalalion~ thus promoting ~imlllt~n~ous fracture of both of the connecting rod
legs. The re-mating of the scpdldted bearing cap to the connecting rod body is
passively accomplished by spring loading the upper portion of the work-holding
fixture to return it to its pre-fracture position. Subsequent to the fracture
30 separation and re-mating of the bipdllile conn~-cting rod, the work-holding fixture,
with its re-mated conn~cting rod still retained and located, can index out of the
separation area for fastener insertion and further proces~ing, as required.
2~ 37
More particularly, this invention provides an appalaLus for the fracture
separation, into a bearing cap and a conn~ g rod, of an integMl preform which
is configured to define a cylindrical apellule and two spaced-apart bolt seat
shoulders, the apl)alalus colll~lisillg:
a base member,
a guide member fixed with respect to said base member, the guide member
defining a first guideway exlelldillg in a first direction,
a first slide member mounted to said guide member for sliding movement
along said first guideway in said first direction, the first slide member defming a
second guideway also extending in said first direction,
a second slide member mounted to said first slide member for sliding
movement with respect to said first slide mPmher along said second guideway in
said first direction,
a mandrel which is split to define an upper part fixed with respect to the
first slide member and a lower part fixed with respect to said base member, saidupper part being movable b~lweell a first position in which it is spaced away from
the lower part and a second position in which it is juxtaposed against the lowerpart to define a subst~nti~lly cylindrical body having its axis Iying substantially in
a second direction p~l~e~ ic~ r to said first direction, movement of said upper
part being simllll~nPuus with movement of the first slide member along the firstguideway with respect to said guide member, the upper and lower parts of said
mandrel defining an internal tapered passageway,
a wedge mPmher adapted, when the upper part is in its second position, to
enter said tapered passageway and force said mandrel parts apart,
power means for moving said wedge member,
projections defined by said second slide member and adapted to contact the
bolt seat shoulders of an integral prefo",l while the cylindrical ape,lule thereof
receives the split mandrel, and
means for selectively urging the second slide member toward the mandrel,
thereby securely holding the integral p,ero,l,l in place,
21I~93 7
whereby the wedge member can enter the tapered passageway, forcing the
mandrel parts apart and fracturing the preform into a bearing cap and a connecting
rod.
Further, this invention provides a process for the fracture separation, into a
bearing cap and a conn~cting rod, of an integral preform which is configured to
define a cylindrical apellulc and two spaced-apart bolt seat shoulders, the process
comprising:
a) fitting the cylindrical apellulc of the pl.,follll over a substantially
cylindrical mandrel which includes sep~te upper and lower parts,
b) holding the plcrOllll in place over the mandrel by pressing against the
bolt seat shoulders in the direction toward the mandrel, and
c) forcing the lllalldl~l parts apart while holding the preform in place,
thereby to fracture the pf~llll into a bearing cap and a coi~ cli"g rod.
BRIEF DESCRIPTION OF THE DRAWINGS
One embodiment of this invention is illustrated in the accompanying
dl~willgs, in which like numerals denote like parts throughout the several views,
and in which:
Figure 1 is an elevational view looking at the front of the separation station
in a direction pel~enfli~ r to the direction of ll~Çel,
Figure 2 is a side elevational view, looking at the sepal~tion station from a
direction at right angles to the direction of Figure 1, and is partly broken away to
show a section along the line 2-2 in Figure 3;
Figure 3 is a horizontal sectional view taken at the line 3-3 in Figure 2,
and the line 3-3 in Figure 1; and
Figure 4 is a view similar to that of Figure 3, showing a variant of the
element causing the fracture separation.
DETAILED DESCRIPTION OF THE DRAWINGS
Figure 1 illustrates, in broken lines, a pre-sepal~lcd preform lA integrally
incol~ora~ g a co~-n~oc~ rod 1 and a bearing cap 2, located and secured in a
separation station work-holding fLxture 3. It is to be noted that the preform lA is
configured to deflne a cylindrical apellule 6 and two spaced-apart bolt seat
shoulders 8 and 9, this being the typical construction.
211~937
s
One of the key feaLu.es of the fixture 3 is the ~tt~inment of a three-point,
wedge-locked retention for the bearing cap 2, both before and after fracturing.
This is accomplished through the use of a small slide assembly 4, which is best
understood by conlpalillg Figures 2 and 3.
S A slide unit 21 is mounted for horizontal movement along the direction of
the arrow 21A. Secured to the slide unit is a base member 30 which is integral
with the lower part 19 of a split nla~ ,l (the rem~in-l~r of which will be
described subseqllently), and a guide member 18. Defined by the guide member
18 is a first guideway 18B which has two oppositely ~lelldillg rectangular
recesses 18A (see Figure 3). The guideway 18B extends in a direction
perpen~ic.~ r to the arrow 21A.
A first slide mPmher S is mounted to the guide member 18 for sliding
movement along the first guideway 18B in the vertical direction (arrow SA in thedrawings), and itself conllil,ul~s to defining a second guideway SB, parallel with
lS the direction of the first guideway. In Figure 3, which is a horizontal section
through the upper part of the assembly shown in Figure 2, a second slide member
10 of rectangular section in its upper portion is trapped between the first slide
member S and a slide assembly cover 12. In Figure 3, the cover 12 defines a
lectall~,ular recess 12A and has lateral projections 12B for securely locating the
cover 12 on the first slide member S. As can also been seen in Figures 1 and 3,
threaded fasteners 13A are utilized to secure the cover 12 against the first slide
member S.
As illustrated in Figure 2, the first slide member S integrally supports an
upper part 7A of a split mandrel 7, from which it will be understood that, when
the first slide member S moves upwardly with respect to the guide member 18, theupper part 7A of the split ll,al~lel 7 moves upwardly away from the lower part
19. It will further be noted that the axis of the split lllalldrel 7 lies in a direction
subst~nti~lly parallel to the arrow 21A, and is thus substantially perpen-1iYll~r to
the first guideway 18B.
As further illustrated in Figure 2, the upper and lower parts 7A and 19 of
the mandrel 7 together define an internal tapered passageway shown in broken
lines at l9A, the passageway l9A being such as to accept a wedge member 20
2I19Y3 7
which, when driven to the left in Figure 2, forces the mandrel parts 7A and 19
apart. It is to be noted that the passageway l9A has a subst~nti~lly hori_ontal
lower portion l9B and a sloping upper portion l9C, and that the leftward end of
the wedge member 20 is correspondillgly configured. The purpose for this
S configuration is to avoid dow~lwdl.l force against the lower part 19, and to
m~ximi7e upward force against the upper part 7A.
Power means for moving the wedge member 20 in Figure 2 is illustrated
sch~m~tir~lly as a hydraulic or pn~ m~tir cylinder 32. As an al~ alive, the
wedge member 20 may be acnl~tr~ by a slaved spring motion of known
construction (not illustrated).
In an allcl"dlive construction, illustrated in broken lines in Figure 4, a
wedge 20A can first come into direct contact with the tapered passageway at a low
force level, creating a pre-load upon the contact surfaces of the internal tapered
passageway, wlRlcupon a sepaldLe high-velocity ram 33 could impact upon the
wedge 20A, thus causing sepdldlion of the preform into a cap and a rod. The pre-load by the wedge has the effect of taking up all slack, and leaving no free travel
or lost motion in the upper and lower parts 7 and 19 defining the internal tapered
passageway l9A. In Figure 4, the ram 33 is the end of a piston 33A moving in a
cylinder 33B. The position of the wedge 20A is controlled by an auxiliary
cylinder 23 acting on a sçh~m~tir~lly illustrated flange 24 secured to the wedge20A.
Referring now to Figures 1 and 2, the second slide member 10 has a
widened portion 34 at the bottom, the portion 34 ~u~ol~ g projections 36 and 38
which are adapted to contact the bolt seat shoulders 8 and 9 while the cylindrical
apc~lulc 6 in the pl._folnl lA receives the split mandrel 7.
Means are provided, ~ltili7in~ a c~mmin~ member 11, for selectively urging
the second slide member 10 toward the mandrel 7, thereby securely holding the
integral ~l~,follll lA in place. In Figure 1, short hatch lines on portions 7A, 36
and 38 show the three-point "capture" of the upper part of the prcrollll lA.
It will now be understood that, when the wedge member 20 enters the
tapered passageway l9A, it forces the mandrel part 7A upwardly away from the
2113937
part 19, thereby fracturing the preform lA into a bearing cap and a connecting
rod.
The c~mming member 11 will now be described in greater detail. The
cover 12 defines a horizontal, rectangular passage llA to either side of the recess
5 12A. The c~mmin~ member 11 is a Z-shaped cam adapted to be moved by a
force along the arrow 13. The upper part of the second slide member 10 is
m~hinlod to define a sloping passageway 40 for receiving a central part 42 of the
cam, having the same slope as the passageway 40. It will be understood that, as
the c~mming member 11 moves leftwardly (as seen in Figure 1), the second slide
10 member 10 will move dOw-lwaldly.
Illustrated schPm~ti~-~lly in Figure 1 are locate and retention locators 14-17.
The locators 14 and 15 are fLxed or static, whereas the retainers 16 and 17 are
dynamic clamps that apply a constant force leftwardly on the preform, seating itfirmly against the locators 14 and 15.
More particularly, the locators 14-17 include a first static locator 14
adapted to contact one side of the portion of the preform lA which is intended to
become the bearing cap, and a second static locator adapted to contact one side of
the portion of the preform lA intended to become the co~ ecling rod. On the
right in Figure 1, the dynamic locator 16 is adapted to contact the other side of the
portion of the pr~fo-lll lA which is intended to become the bearing cap, while the
second dynamic locator 17 is adapted to contact the other side of the portion of the
preform lA which is intended to become the conn~cting rod. The dynamic
locators 16 and 17 can be urged leftwardly by the use of resilient means, such as
springs. The locators 14 and 16 are mounted on the first slide member 5 while
the locators 15 and 17 are mounted on the base member 30. It will thus be seen
that, even though the part carrier is used for Lldh~f.,llhlg the connecting rod from
one m~ in~ station to another, the locators remain engaged with the plefol.ll (the
conn.octing rod components) throughout the fracture and separation cycle.
Utilization of the illustrated appa~dlus may be defined as a process for the
fracture sepdld~ion, into a bearing cap and the connecting rod, of an integral
preform configured to define a cylindrical apellule and two spaced-apart bolt seat
shoulders. The process involves first fitting the cylindrical apellure of the
21~g37
preform lA over the subst~nti~lly cylindrical mandrel 7 that includes separate
upper and lower parts 7A and 19 respectively, then holding the preform lA in
place on the mandrel 7 by causing the projections 36 and 38 to press downwardly
against the bolt seat shoulders 8 and 9 rc~e~;lively in the direction toward the5 mandrel then forcing the parts 7A and 19 apart (while holding the preform lA in
place) thereby fracturing the preform lA into a bearing cap 2 and a connecting rod
1. Upon fracture, caused by the high-velocity of the wedge member 20 entering
between the lllanllel halves 7A and 19, the following portions move vertically
upward: the first slide member 5 with its integral part 7A of tne split mandrel 7;
the cover 12, the second slide member 10, the cam member 42, the locators 14
and 16, and the bearing cap 2 (which has been split from the co..,~P~l;"g rod 1).
The following parts remain stationary: the lower part 19 of the ~ a~ g
mandrel 7, the guide m~mher 18, the base member 30 and the slide unit 21.
TmmP~ tely upon completion of fracture separation, the wedge member 20
15 is withdrawn from bclwcen the mandrel halves 7A and 19, allowing the first slide
member 5 to return to its pre-separation position. Actuation to return the firstslide member 5 dowllwdr.lly can employ any linear force device (springs,
cylinders, etc.), or gldvi~lion.
It will now be understood that the a~palalus and process described above
20 allow the bearing cap 2 to be fracture-sepalated from the conn~cting rod body 1,
while all throughout the sepala~ion and re-mating process the location uniqueness
of the bearing cap 2 with respect to the co~ P~ rod body 1 is m~int~in~l
With respect to the slide unit 21 seen in Figure 2, its purpose is 1) to bring
the e4ui~lllelll required to Sepaldle and re-mate the connPctin~ rod bipallilc while
25 it is located and retained in the part carrier, and 2) to pelrollll separation and re-
mating, and then withdraw from the conl-~c~ rod bi~allilc, leaving it located
and retained as it was prior to separation.
While this invention has been described and illustrated with the conn~cting
rod preform lA in a vertical attitude, the particular part attitude is not a limitation
30 of this invention. The process outlined above can be carried out with the
conn~cting rod in any desired attitude. Of course, the various slides, actuators,
clamps, locators and directions of motion, as previously described, would change
3 ~
g
their attihldes in a similar way, in order to keep the relative motions and directions
consistent.
A detailed description of the process follows:
Firstly, the locators 14-17 are activated to grip the preform.
Secondly, with the second slide member 10 withdrawn upwardly such that
the projections 36 and 38 do not h~ r~,.e, the preform aperture 6 is engaged with
the split mandrel 7 and the ram slide assembly by a linear motion, with the split
mandrel parts 7A and 19 being juxtaposed against each other.
Next, the three-point retention of the comlecting rod bearing cap is
activated, this taking place bclwcen the cap half 7A of the split mandrel 7 and the
projections 36 and 38, which contact the bolt seat shoulders.
Then, the wedge member 20 or the wedge 20A is activated to split the
mandrel 7, following which the wedge member 20 or wedge 20A is withdrawn.
Then, the bearing cap retention co~ ecl by the projections 36 and 38 is
disengaged.
Then, the split lllalldfel and the ram slide assembly is disengaged from the
CO~ Ct;l-g rod by moving the slide unit 21 (illustrated in Figure 2).
Finally, the locators 14-17 are disengaged at the point of removal of the 2-
piece plcfoll~l which has been re~csemhled using two bolts.
While one embodiment of this invention has been illustrated in the
accolll~allyillg dlaw~ and described hereinabove, it will be evident to those
skilled in the art that changes and mo lifir~tions may be made therein without
departing from the essence of this invention, as set forth in the appended claims.
