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Description  |
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FIELD OF THE INVENTION
This invention relates to a roller chain and in particular to an improved
roller chain having substantially increased tensile and fatigue strength
created by connecting the individual link plates to the respective bushes
by means of a fillerless fusion weld created by electron beam or laser
welding.
BACKGROUND OF THE INVENTION
Conventional steel roller and conveyor-chains are made by alternately
joining together an inner link subassembly comprising an inner link plate
and a bush pressed therein and an outer link subassembly comprising an
outer link plate and a pin pressed therein. When these chains are
subjected to tensile load, bending and shearing stresses are exerted on
the pin and bush, while tensile stress is applied on the link plates.
Particularly, the perforated portion of the link plates where the pin or
bush is inserted yields under such tensile stress, thereby giving rise to
plastic deformation. Because of this, the engaging force between the outer
link plate and the pin and the inner link plate and the bush is reduced,
and engagement therebetween is liable to be loosened. Such reduction in
engaging force and loose engagement lower the durability of the chain and
cause such damages as fatigue and wear rupture of the link plates, pin and
bush. To improve the fatigue strength (dynamic strength) of a chain, the
following mechanical measures are generally taken:
1. Improvement of paralleledness and machining accuracy of the perforated
portion of the link plate.
2. Chamfering of the hole in the link plate.
3. Increase of engaging force between the link plate and the pin or bush
through the increase of interference therebetween.
4. Pre-exertion of residual compressive stress on the perforated portion of
the link plate.
Despite the adoption of these methods, the dynamic performance of the chain
is reduced in actual use by the loosening of engagement under the
influence of thermal stress occurring under the actual operating
condition, atmosphere in use, suitability of machine work, and other
factors. Therefore, these are not the perfect measures to improve fatigue
strength.
In an effort to improve the dynamic strength of conventional steel roller
chains, the link plates have often been welded to the respective pins and
bushes by welding techniques utilizing a filler material, such as the
well-known arc-welding technique. However, the resulting chains produced
using filler-type welds between the link plates and the respective pins or
bushes have not provided any significant increase in the strength and
durability of the chain, particularly as regards the dynamic or fatigue
strength characteristics.
Accordingly, the object of the present invention is to provide a
substantially improved roller chain which utilizes a fillerless fusion
weld between the link plate and the respective pins or bushes, which
fillerless weld results in the chain having substantially increased
dynamic strength characteristics.
Specifically, the present invention proposes to render the inner link
plates and the bushes, and the outer link plates and the pins, into a
complete integral body by welding their total engaged surfaces together by
means of a precision welding technique, specifically electron beam
welding, or laser welding, thereby providing a fillerless fusion weld
along the total engaged surfaces of the respective elements while
producing extremely little deformation.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a front view illustrating three links of a chain constructed
according to the present invention.
FIG. 2 is a cross-section view taken along the line II--II of FIG. 1.
FIG. 3 is a fragmentary cross-sectional view illustrating an arc-welded
inner link assembly which was utilized for experimental test purposes.
FIG. 4 is a fragmentary cross-sectional view illustrating an electron-beam
welded inner link assembly according to the present invention, as used for
experimental test purposes.
FIG. 5 is a fragmentary cross-sectional view of an electron-beam welded
outer link assembly according to the present invention, as utilized for
experimental tests.
FIG. 6 is a perspective view of an arc-welded inner link assembly prior to
experimental testing.
FIG. 7 is a perspective view of an electron beam welded inner link assembly
according to the present invention, prior to experimental testing thereof.
FIG. 8 is a side view illustrating the electron beam weld created between
the bush and pin and the respective link plates, in accordance with the
present invention.
FIG. 9 illustrates four chain samples which were experimentally tested,
Chain No. 1 being a conventional engaged-type chain, Chain No. 2 being an
arc-welded chain, and Chain No. 3 and 4 being electron beam welded chains
according to the present invention.
FIG. 10 is a side view of the engaged type chain (Chain No. 1) illustrating
the fracture which occurred in the bush link plates when the chain was
experimentally subjected to tensile testing.
FIG. 11 is a perspective view of the arc-welded chain (Chain No. 2) and
illustrating the fracture which occurred in the bush link plates after
subjecting the chain to experimental tensile testing.
FIG. 12 is a perspective view of an electron beam welded (Chain No. 3) and
illustrating the fracture which occurred in the pin link plate upon
subjecting the chain to experimental tensile testing.
FIG. 13 is a perspective view of an electron beam welded chain (Chain No.
4) and illustrating the fracture which occurred in one of the pins upon
subject the chain to experimental tensile testing.
FIG. 14 is a further perspective view of the chain illustrated in FIG. 13
but with one of the pin side plates removed to more clearly illustrate the
fracture of the pin.
FIG. 15 is a plot illustrating the experimental tensile rupture strength
versus the chain pitch.
FIG. 16 is a plot illustrating the experimental chain fatigue strength
versus chain pitch.
FIG. 17 is a plot illustrating the conventional fatigue characteristic
curve of an electron beam welded chain (Chain No. 4) according to the
present invention in contrast to an arc-welded chain.
FIG. 18 is a plot illustrating the relationship between the mean static
tensile rupture strength versus the fatigue limit for the different types
and sizes of chains.
DETAILED DESCRIPTION
Referring to FIGS. 1 and 2, reference numerals 1 through 4 designate an
outer link plate, an inner link plate, a pin and a bush, respectively. The
entire circumference of a portion at which said outer link plate 1 and pin
3 are engaged with each other is precision welded, as shown by A and A',
and the same is the case with the engaged portion of said inner link plate
2 and bush 4, as shown by B and B'. However, the pin 3 and the bush 4 are
not necessarily welded at both ends. Instead they may be welded at only
one end, with the other end being left just engaged so far as suitable
arrangements are furnished to keep a balance between the welded and the
engaged portions. Otherwise, either of said pins 3 or bushes 4 may be
welded, with the remainder being just engaged.
Welding is performed from outside the link plate. The weld must be as thick
as or thicker than the full thickness of the link plate, so that the
entire engaged surface (both axially and circumferentially) of the engaged
portions are perfectly joined by a fillerless fusion weld. With respect to
such welding of the engaged portions of the inner and outer links, the
problem of welding depth at the engaged portions and the heat treatment
specifications for the part thus welded requires particular attention from
a performance viewpoint. As machined parts (that is pins, bushes and link
plates) are assembled into inner and outer link subassemblies. Then said
link subassemblies are combined into one piece by welding the entire
circumference of the engaged portions by a precision welding method. After
this, heat treatment (such as hardening, tempering or isothermal
transformation heat treatment) is given to improve the welded structure.
By this means, the most stabilized quality and other excellent
characteristics are obtained.
According to this invention, the outer link plates and the pins, and the
inner link plates and the bushes, are perfectly fixed at both ends instead
of being simply supported at both ends. The result is that both the inner
and outer links are imparted with higher rigidity, provided with greater
effective cross-sectional area at their ring-shaped portion, and kept free
from loose engagement. By the accumulation of such effects, the static and
dynamic strength of the chain is increased remarkably. In the case of
bushed chains with the engaged portion of their inner link plates and
bushes being electron beam welded, the static tensile rupture strength and
fatigue strength are from 1.42 and 1.95 times greater than those of
unwelded chains. With electron beam welded bushed chains are made up of
link plates, bushes and pins, the inside and outside diameters of a bush
and the diameter of a pin can be increased to a suitable extent as
compared with ordinary roller chains of the same chain pitch, resulting in
greater static tensile rupture strength and fatigue strength (up to about
twice as great). This makes it possible to design a compact chain
transmission system.
With regard to wear life, the possibility to increase the radius of
curvature of the contact surface of the pin and bush results in increasing
effective bearing area and decreasing surface pressure. This improves the
bearing performance, which in turn improves the wear life of the chain.
With the conventional chains comprising the combination of the inner link
plate and the bush and the outer link plate and the pin, there is a
general tendency to attempt to improve their durability by increasing the
engaging force by increasing the interference therebetween. This however
deforms the inside of the bush. To be more precise, the inside of the bush
becomes barrel-shaped on engagement with the link plate, and this tendency
to deformation increases with increasing interference. This reduces its
contact with the pin to a linear contact only at both ends, thereby
rendering it impossible to make effective use of the bearing area. This
results in an increase in the initial wear elongation of the chain.
On the other hand, with the electron beam welded chains of the present
invention, the inner link plate and the bush are engaged with each other
by light interference fit or some other means like that. As compared with
the engaged-type chains having bushes of the same inside diameter and pins
of the same outside diameter, the inside of the electron beam welded chain
bush is much less liable to become barrel-shaped. Besides, welding strain
also is very limited. All this makes the effective bearing area large.
Consequently, the electron beam welded chains suffer from little initial
wear elongation, and therefore acquire greatly extended service life.
Finally, corrosion, heat (characteristics at high temperature) and
atmosphere resistance of the electron beam welded chains of the present
invention will be discussed. Corrosion, oxidation and stress corrosion
cracking of the engaged portions under various atmospheres, creep rupture
of the link plate starting from the engaged portions at high temperatures,
reduction in durability of the chain due to relaxation of stress etc., and
rupture of the chain, which are commonly the case with the conventional
steel-made engaged-type chains, are reduced. In addition, this invention
permits integral combination of different materials best suited to the
intended application and the condition of use. For these reasons, the
above-mentioned resistances are greatly improved. All this makes the
electron beam welded chains suitable to such applications where low speed
and large load are involved, where heat and corrosion resistance are
needed, where water treatment is intended, and where durability and
resistance to various atmospheres are required. Furthermore, the chains
can be made more compact. They are also applicable as offset and other
similar chains.
Referring again to FIGS. 1 and 2, the inner link subassembly which is
formed by the two bushes 4 and the two inner side plates 2 are welded into
one piece, with the fillerless welds B and B' extending throughout the
complete width of the side plates 2 so as to create the desired joining of
the bushes and side plates throughout the complete engaging areas thereof.
This results in a maximum joining between the individual pieces due to the
use of electron beam welding.
In a similar manner, the outer link subassembly is formed into one piece by
welding the two pins 3 to the two outer side plates 1 so as to create the
fillerless welding regions A and A'. These welding regions extend
throughout the complete width of the side plates 1 so as to optimize both
the engaging and the welded area between the plates and the pins.
As illustrated in FIG. 2, the use of electron beam welding for joining the
bushes and pins to the respective link plates permits the use of link
plates which are substantially flat and of substantially uniform
thickness. Further, use of electron beam welding permits the ends of the
pins and bushes to terminate substantially flush with the outer surfaces
of the respective link plates, and the weld areas themselves terminate
substantially flush with the outer surfaces of the link plates.
The substantial and unexpected improvement in both the static and dynamic
strength, that is tensile and fatigue strength, which results from using
electron beam welding for forming a chain according to the present
invention, in contrast to the much lower static and dynamic strength which
exists in conventional engaged type chains and arc-welded chains, will now
be explained in detail with reference to accompanying Tables I and II and
in conjunction with FIGS. 3-18. These tables and figures graphically
depict and illustrate a lengthy and complex experimental evaluation which
was conducted on the present invention.
A number of different chain samples were both statically and dynamically
tested to demonstrate the substantial improvement in both the tensile and
fatigue strengths which result when a roller chain is electron beam welded
according to the present invention. The first chain sample designated No.
1 comprises a conventional engaged-type chain, whereas the second chain
sample designated No. 2 involves an arc-welded chain wherein the bushes
were connected to the respective side plates by a conventional filler-type
weld. The third sample designated No. 3 utilized electron beam welding
according to the present invention, which electron beam welding, existed
at all of the connections between the bushes and respective side plates,
and some of the connections between the pins and respective side plates.
Sample No. 4 was also an electron beam welded chain according to the
present invention and represents a desirable embodiment, and in the sample
the bushes were all electron beam welded to the respective side plates.
Samples No. 3 and 4, since they both utilize electron beam welding, but
were of slightly different welded structure in terms of the actual welding
connections involved, have been referred to as the A-type and B-type
chains, respectively.
Referring to Table I, same presents therein a listing of the dimensions and
heat treatment specifications of the individual parts for the chain
samples No. 1-4. All of the chain samples were of the same size, that is a
chain pitch of 50.80 mm (equivalent to A.N.S.I. designation No. 160), and
all chain samples were of high strength steel.
FIGS. 3-5 illustrate therein the specific configuration used for the
samples according to the experimental test program. FIG. 3 specifically
illustrates therein the structure of the arc-welded bush link subassembly
incorporated into sample No. 2, whereas FIG. 4 illustrates the electron
beam welded bush link subassembly as incorporated into samples 3 and 4.
FIG. 5 illustrates the electron beam welded pin link subassembly as
incorporated into Sample No. 3.
FIGS. 6 and 7 are comparative photographic representations of the
appearance and shape of the bush link subassembly produced by arc welding
and electron beam welding, respectively. As is readily apparent from these
illustrations, the electron beam welded bush link subassembly (FIG. 7) of
the present invention (which bush link subassembly corresponds to both
A-type and B-type chains) has a substantially greater commercial value
than the arc-welded bush link subassembly of FIG. 6, since the electron
beam welded bush link subassembly has substantially improved accuracy and
higher quality workmanship.
FIG. 8 is a photographic representation of the appearance and shape of the
electron beam welded bush link subassembly and pin link subassembly
according to sample No. 3 (A-type), and again illustrates the
substantially improved accuracy and workmanship which results from using
electron beam welding.
Referring now to Table II, same lists therein the details of the test
procedures and also the results of the breaking experiments performed on
chain samples No. 1-4 as listed in Table I.
Table II compares the mean value of the tensile rupture strength for the
different chain samples. The arc-welded chain (sample No. 2) showed a
rupture strength 1.24 times greater than that of the No. 1 chain, with
rupture in the arc-welded chain occurring in the welded portion of the
bush link subassembly. In contrast, the B-type chain (sample No. 4)
according to the present invention had a rupture strength which was 1.63
times greater than the rupture strength of the No. 1 chain. Thus, the
B-type chain of the present invention showed a 63 percent increase in
tensile strength in comparison to a conventional engaged type chain
(sample No. 1), whereas the B-type chains of the present invention also
showed a 31 percent increase in tensile rupture strength in contrast to an
arc-welded chain (sample No. 2). The electron beam welded chain, and
specifically the B-type chain, thus exhibited a rather large increase in
strength. Further, in the B-type chain (sample No. 4), the rupture did not
occur at the bush link subassembly, such as in the engaged and arc-welded
samples, but rather the rupture in the B-type chain occurred due to a
failure of one of the pins. This thus indicates that the weakness of the
engaged-type and arc-welded chains, which weakness occurs in the bush link
assembly, has been totally overcome when utilizing an electron beam welded
B-type chain of the present invention since the failure now occurs in a
totally different element, namely the pin. Since the pin itself can be
provided with greater strength if desired by appropriate material
selection and/or heat treatment, it thus becomes apparent that a chain
utilizing electron beam welding according to the present invention (such
as a B-type chain) can thus be provided with even greater rupture strength
if desired. Further, in the B-type chain sample, the thickness of the pin
link plate was slightly greater than the thickness of the bush link plates
in order to balance the strength of the individual parts.
Referring to FIG. 10, same is a photograph of the No. 1 chain after rupture
thereof during experimental tensile testing thereof. This photograph
illustrates that the rupture occurs in the link plates associated with the
bush link subassembly. In a similar manner, FIG. 11 is a photograph of the
arc-welded chain (sample No. 2) after same had been ruptured during
tensile rupture testing. FIG. 11 illustrates that the arc-welded chain,
like the engaged chain, ruptures due to a failure in the vicinity of the
weld between the bush and the respective link plates.
On the other hand, FIGS. 13 and 14 are photographs of chain sample No. 4
(the B-type chain) which was constructed utilizing electron beam welding
according to the present invention. FIGS. 13 and 14 indicate that the
rupture in this chain sample occurred due to a shear fracture of one of
the pins. No failure or noticeable weakness is exhibited adjacent any of
the welded connections in the bush link subassembly.
FIG. 12 is a photograph of sample No. 3 (A-type) and illustrates that the
rupture in this case took place in one of the link plates associated with
the pin link subassembly, and specifically the rupture occurred in the
region between the link plate and pin which were engaged but not welded
together.
Thus, as is believed apparent from the above discussion with reference to
the accompanying figures, causing each of the bush link and pin link
subassemblies to be formed into an integral one-piece body by fusing their
total engaged surfaces together by a precision welding method, such as
electron beam welding, drastically increases the tensile strength of a
chain made up of such parts.
Referring to FIG. 15, same is a graphical comparison, based on the
experimental values, of the relationship between the chain pitch and the
mean tensile rupture strengths for a B-type chain according to the present
invention and a conventional engaged-type roller chain conforming to the
A.N.S.I. standards. As understood from this comparison, the rupture
strength of a B-type chain is comparable to that of a roller chain which
is two sizes larger.
FIG. 16 comprises, based on experimental values, the relationships between
the chain pitch and the fatigue limit for a B-type chain according to the
present invention and a conventional engaged-type roller chain. As is
evidence from this figure, the fatigue limit of the B-type chain is
comparable to that of a roller chain which is three or four sizes larger.
FIG. 17 illustrates the characteristic fatigue curve (normally referred to
as an S-N curve) for the B-type chain of the present invention and an
arc-welded chain of the same size. The curves in FIG. 17 are plotted based
on experimental results. As the curves of FIG. 17 illustrate, the fatigue
limit for a B-type chain according to the present invention is more than
two times greater than that of an arc-welded chain of the same size.
FIG. 17 also indicates that the B-type chain of the present invention
results in a greatly increased life in comparison to an arc-welded chain
of the same size when operating within the low-cycle fatigue limit. For
example, as noted in FIG. 17, when an arc-welded chain is operated
repetitively under a load of 10,000 kilograms, it will have a life of
10.sup.4 cycles prior to fatigue failure. On the other hand, the same
size B-type chain when operating repetitively under a load of 10,000
kilograms will have a life of 5 .times. 10.sup.5 cycles prior to fatigue
failure. The fatigue life of the B-type chain of the present invention, in
contrast to the same sized arc-welded chain, is thus approximately 50
times of the arc-welded chain when operating within the low-cycle fatigue
limit. Needless to say, this represents a very substantial and unexpected
improvement when operating under conditions of this type.
Referring now to FIG. 18, same compares the relationships between the
rupture strengths and the fatigue strengths (or the fatigue limit) for the
B-type chain of the present invention and a conventional engaged-type
roller chain conforming to the A.N.S.I. standards. This figure also
illustrates thereon the relationship of the tested arc-welded chain in
contrast to the tested samples of the engaged-type and B-type chains.
As FIG. 18 indicates, the tensile rupture strength of the arc-welded chain
(size No. 160) is comparable to that of a B-type chain which is one size
smaller (Size. No. 140 having a chain pitch of 44.45 mm). Further, the
fatigue limit of the arc-welded chain of Size No. 160 is comparable to the
fatigue limit of a B-type chain of Size No. 100 (chain pitch = 31.75 mm),
which B-type chain is three sizes smaller than the arc-welded chain.
Thus, compared with an arc-welded chain of the same size, the B-type chain
according to the present invention results in an increase in the rupture
strength of greater than 30 percent and results in a fatigue limit which
is more than two times greater than that of the same size arc-welded
chain.
In a similar manner, when comparing the B-type chain of the present
invention to a conventional engaged-type roller chain, the B-type chain of
the present invention results in a rupture strength comparable to that of
a roller chain which is two sizes larger and the B-type chain results in a
fatigue limit which is comparable to that of a roller chain which is three
to four sizes larger.
While the experimental comparison set forth above could have been extended
to chains having the bushes and/or pins braised to the link plates,
nevertheless such tests were not conducted since it is well known that
such braised connections are obviously inferior in strength to the
connections produced utilizing arc-welding. Further, high frequency
welding techniques are disadvantageous since they result in undesirable
defects, such as excessive deformation of the chain.
Although a particular preferred embodiment of the invention has been
disclosed in detail for illustrative purposes, it will be recognized that
variations or modifications of the disclosed apparatus, including the
rearrangement of parts, lie within the scope of the present invention.
Table I
__________________________________________________________________________
DIMENSIONS AND HEAT TREATMENT OF INDIVIDUAL PARTS OF CHAINS TESTED
No. 1 No. 2 No. 3 No. 4
Engaged-type
Arc-Welded Chain
Electron Beam Welded
Electron Beam Welded
Chain Chain Chain
A-Type B-Type
__________________________________________________________________________
Chain Pitch 50.80 50.80 50.80 50.80
Pin Diameter
16.70 16.70 16.70 16.70
Bush Outside
28.58 28.58 28.58 28.58
Dimension
Diameter
of Pin Thickness
6.4 6.4 6.4 8.0
Link
Parts Plate
Width 41.6 48.2 48.2 48.2
(mm) Bush Thickness
6.4 6.4 6.4 6.4
Link
Plate
Width 48.2 48.2 48.2 48.2
Bush Link In-
31.75 31.75 31.75 31.75
side Width
Material
Pin SAE 4340 SAE 4340 SAE 4340 SAE 4340
of Bush SAE 4135 SAE 4135 SAE 4135 SAE 4135
Parts Pin Link Plate
SAE 4135 SAE 4135 SAE 4135 SAE 4135
Bush Link Plate
SAE 4135 SAE 4135 SAE 4135 SAE 4135
Harden-
860.degree.C-20 minutes
860.degree.C-20 minutes
860.degree.C-20 minutes
860.degree.C-20
minutes
ing Oil Quenched
Oil Quenched
Oil Quenched
Oil Quenched
Pin
Temper-
200.degree.C-180 minutes
200.degree.C-180 minutes
200.degree.C-180
200.degree.C-180
minutes
ing Air Cooled Air Cooled Air Cooled Air Cooled
Harden-
870.degree.C-20 minutes
870.degree.C-20 minutes
ing Oil Quenched Oil Quenched
Bush
Temper-
430.degree.C-180 minutes
200.degree.C-180 minutes
Welding ing Air Cooled Air Cooled
Harden-
870.degree.C-20 minutes
870.degree.C-20 minutes
870.degree.C-20 minutes
870.degree.C-20
minutes
and Pin ing Oil Quenched
Oil Quenched
Oil Quenched
Oil Quenched
Link Temper-
430.degree.C-180 minutes
430.degree.C-180 minutes
430.degree.C-180
430.degree.C-180
minutes
Heat Plate
ing Air Cooled Air Cooled Air Cooled Air Cooled
Treatment
Harden-
870.degree.-20 minutes
870.degree.C-20 minutes
of Bush ing Oil Quenched Oil Quenched
Link Temper-
430.degree.C-180 minutes
430.degree.C-180 minutes
Parts Plate
ing Air Cooled Air Cooled
After assembling pins
and pin link plates
into a pin-link sub-
Bush assembly, following
the above heat treat-
Weld- ments, the entire
Link ing portions where the
Plate pins and pin link
plates were engaged
Sub- were fused together
assembly by electron-beam-
welding.
Temper- 200.degree.C-180 minutes
ing Air Cooled (to re-
After move welding strain
Welding
After assembling
After assembling
After assembling
edge-prepared bushes
bushes and bush link
bushes and bush link
and bush link plates
plates into a bush-
plates into a bush-
into a bush-link sub-
link subassembly,
link subassembly, the
assembly, all of the
following the above
entire portions where
Bush edge-prepared port-
heat treatments,
the bushes and bush
Welding ions were arc-welded,
entire portions
link plates were en-
Link using Type MA-96
where the bushes
gaged were fused to-
welding rod for SAE
and bush link plates
gether by electron-
Welding
Plate 4135 made by Kobe
were engaged were
beam-welding to make
Steel, Ltd.
fused together by
a one-piece bush
link.
and Sub- electron-beam-
Welding depth
.gtoreq.Bush
assem- welding. Welding
link plate thickness.
Heat bly depth = Bush link
plate thickness.
Treat- Harden- 870.degree.C-30 minutes
870.degree.C-30
minutes
ment ing after Oil quenched Oil Quenched
of welding
Tempering 430.degree.C-180 minutes
200.degree.C-180
430.degree.C-180
minutes
Parts after Air Cooled Air Cooled (to re-
Air Cooled
welding move welding strain)
Pin Rc 52-54 Rc 52-53 Rc 52-53 Rc 52-53
Hardness
of Bush Rc 42-43 Rc 42-43 Rc 50-51 Rc 42-43
Parts Pin Link Plate
HB 388.about.401
HB 388.about.401
HB 388.about.401
HB 388.about.401
Bush Link Plate
HB 388.about.401
HB 388.about.401
HB 388.about.401
HB 388.about.401
__________________________________________________________________________
##SPC1##
__________________________________________________________________________
1 28,200 35,000 42,500 46,300
2 28,400 35,300 42,500 46,400
Experimental
3 28,600 35,500 42,600 46,500
Tensile
Valves 4 28,700 35,600 42,800 46,500
Rupture 5 28,700 35,800 43,100 46,800
Strength
Statistical
x 28,520 35,440 42,700 46,500
(Kg) Valves R 500 800 600 500
.sigma.
194 273 255 167
All in the per-
All in the welded
All in the perfor-
Breaking forated portion
portion of the bush-
ated portion in the
of the bush link
link subassembly,
pin link plate, but
Position plate (See FIG.
but closer to the
closer to where the
The pin (See FIGS.
10) perforated portion
pin is engaged (see
13 and 14).
of the bush link
FIG. 12).
plate (see FIG. 11).
12).
Compared with
Mean Claim No. 1
1.00 1.24 1.50 1.63
Compared with
Strength
Claim No. 2
0.80 1.00 1.20 1.31
Compared with
Ratio
Claim No. 3
0.67 0.83 1.00 1.09
Compared with
Claim No. 4
0.61 0.76 0.92 1.00
__________________________________________________________________________
* * * * *
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