Note: Descriptions are shown in the official language in which they were submitted.
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"Caterpillar (trade mark) Track"
The instant invention relates to a caterpillar
ttrade mark) track, the chain links of which comprise
tubular bodies arranged transversely of the direction
of movement and connected to the adjacent chain links,
as seen in the direction of movement, by connector
links as well as bolts which extend through' the connec-
tor links and through the tubular bodies.
In operation the bolts extending through the
tubular bodies and connector links are subjected to
bending stresses which may be caused by the traction
drive force acting transversely of the bolts in the
direction of movement of the chain but may also have
their origin in weight load acting in vertical direction
at driving conditions at which the chain is supported
on the ground at its edges only, for example when driving
over a rut\or groove in the ground.
It is a principal aspect o~ the present inven-
tion to design a caterpillar track of the kind de~ined
such that its elements, in particular the bolts may
have smaller dimensions and weight than hereto~ore
possible to withstand and endure a given bending load.
It is another aspect of the invention to
provide a chain link of smaller overall dimensions
for a caterpillar track, thus enabling savings of material,
manufacture and storage expenditure.
It is still another aspect o~ the invention
to prevent the ends of the bolts used in a caterpillar
track from slipping with respect to the corresponding
connector links by providing for form-lock or friction-
lock engagenlent of the bolts end.
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Accordingl~, this invention provides connector
means for connecting together the adjacent ends of
successive chain links of an endless track, comprising:
~a) an end connector mem~er containing trans-
versely extending through openings at its forward and rear
ends, respectively, each of said through openings including
(1) a curved first inner wall contact surface
which comprises, in transverse cross-section, a
segment of a circle, and
(2) a flat second inner wall contact surface,
said contact surfaces extending the length of said
through opening; and
(b) a pair o~ cylindrical rod members extending at
one end within said openings, respectively, each of said
rod members having on its outer periphery
(1) a curved first outer wall contact surface
in contiguous frictional engagement with said first
inner wall contact surface, and
(2) a flat second outer wall contact surfàce
in contiguous frictional engagement with said
second inner wall contact surfacè, whereby said
contact surfaces cooperate to prevent rotation of
said rod mem~er relative to said end connector
member;
(c) each of the cu~ved and flat contact surfaces
of one of said members containing at least one groove, whereby
when th~ corresponding curved and flat contact surfaces
are pressed tightly together in tight frictional engagement
foreign matter is removed from the contact surfaces to
produce a large constant frictional force between the members
for preventing axial displacement of the rod member relative
to the connector link.
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In this manner overload protection of the
bolts is obtained which permits the desired smaller
dimensions to be applied at given permissible bending
loads. With a caterpillar track according to the inven-
tion, starting with the predetermined flexure causedespecially by vertical bending stress, for instance,
by the weight of a vehicle equipped with the caterpillar
track, it is no longer the bolts alone which accommo-
date the bending load but, in addition, also the tubular
bodies and, if desired, the connector links. Thus
the bolts enjoy partial relief of the bending stress so
that they may be designed weaker in diameter. In the
same manner also the dimensions of the bores which receive
the bolts in the tubular bodies and determine the dimen-
sions of the tubular bodies and the bores in the connectorlinks may be made smaller. This permits a smaller
overall size of the chain link and thus offers savings in
material, manufacture, and storage expenditure. This is
achieved simply by mutual fitting of the tubular bodies
and/or connector links transversely of the direction of
movement, i.e. in their longitudinal extension. In
practice a clearance will be provided within such limits
of tolerance between the tubular bodies and/or the
connector links as will be taken up from the predeter-
mined flexure on. In the critical case in which the
predetermined flexure is zero, the tubular bodies and/or
connector links already abut each other laterally even
when not subjected to loading so that from the very
beginning the bolts are subjected to less bending stress.
In a caterpillar track in which the tubular
bodies and/or connector links include webs extending
into spaces between adjacent elements oE a chain
link or between two successive chain
links, as seen in running direction, so as to enlarge the roll-
off surface for the chain wheels and thus afford smoother
running, the tubular bodies and/or connector links may support
each other laterally through those webs which are dimensioned
or fitted accurately in the direction of movement as well as
transversely thereof. With known caterpillar tracks a
retaining force between the bolt ends and the end connectors
usually is obtained by clamping the two halves of an end
connector of divided or integral structure against each other
by means of a clamping bolt. Thereby the end connectors
provided with recesses hold the bolt ends clamped, for instance,
at flat sections of the bolt ends and connectors abutting
each other and extending parallel with the axis. The frictional
retaining force thus established is limited. Yet it is suffic-
ient when it is not necessary to transmit axial forces betweenthe bolts and the end connectors. However, if also axial
forces must be transmitted and if slipping of the bolts in
their longitudinal direction with respect to the end connectors
is to be prevented particularly with a caterpillar track
provided with the above mentioned kind of lateral support of
the tubular bodies and/or the connector links according to
the invention, the retaining force generated in the known manner
is not sufficient. This is so because, on the one hand, the
axial forces between the bolts and the end conne ~ rs may
become very large and, on the other hand, because the tighten-
ing torque of the clamping bolt and the coefficient of friction
between the bolts and the end connectors, which two parameters
determine the magnitude of the retaining force, cannot be kept
constant in practice.
Assembling is rendered difficult by the need for
constant accurate adjustment according to specification of
the tightening torque and is practically impossible under the
rough actual conditions of replacement of chain elements in
practice. Moreover, it cannot be avoided with the known design
that lubricant or dirt particles enter between the frictionfaces when mounting or exchanging chain elementsO Consequently
the coefficient of friction varies uncontrollably. Thus the
tightening torque prescribed for a certain coefficient of
friction does not correspond to the respective coefficients
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of friction prevailing in actual practice. Undesired slipping
of the bolts relative to the end connectors may be the result
so that the end connectors and/or bolts will no longer have
the proper operating positions. This may be the cause of
uneven running and damages of the track.
Therefore, it is another aspect of a preferred form
of the present invention to design a caterpillar track of the
kind defined initially such that the bolt ends are prevented
from slipping with respect to the end connectors which are
disposed laterally of the caterpillar track to connect adjacent
chain elements. This is particularly important with a cater-
pillar track having the above described kind of lateral support
devised by the invention because when a caterpillar track of
such design bends, there is a strong tendency for the bolts
to slip axially with respect to the end connectors. And this
would entail all the disadvantageous consequences mentioned.
To solve this further problem it is-provided, in
accordance with a preferred form of the invention, that in
addition to being secured against rotation at least one bolt
end of the two bolt ends associated with an end connector is
further secured against uncontrolled axial slippage with respect
to the corresponding end connector which is particularly
advantageous with a caterpillar track having the lateral
support described above between the tubular bodies and the
end connectors, when this track is subjected to bending stress.
The embodiments below demonstrate the great variety
of form-
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and friction-lock connections which can be used -to realize
the invention. In a preferred embodiment of a form-lock
connection a bu3hing or sleeve functioning as fitting piece and
having flat sections at two side~, especially flat section~
inclined in two directions, i9 pressed against corresponding flat
sections at the bolt ends~ particulary by means o~ a clamping
.bolt or screw con~ecting t~e bushing with the end conneotor.
The fitting piece may be a fitting part of a clamping bolt
~crewed into the end connector.
preferred embodiment
In another/the fitting piece is a disc which fits into a slit
between the halves or bridges of a conventional end connector
and through which a screw passes centrally. ~y means of opposed
pro~ections this disc engages in transverse grooves in the bolt
~nda. ~hi~ embod$m~ p~aiall~ ~oo~omic~l b~o~u~ per-
mits the use o conventional end connectorsiwi.thout any alteration
and merely requires the disc a~ an ad~it~pnal member.
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A form-loc~ connection advantageously may also be realized a9 a
bayonet connection.
In th~ case of a friction-lock connection the structure is to
be design~d suchlthat a defined ~riction force is generated
which positively ~urpasse~ axial displacement and/or tor~ional
f orces G
Such frictional force is realized, for example~ by u;8ing
wedgi.ng action in that very great normal forces giving rise to
corre~ponding frictional force~ are produced between circum-
~erential sur~ace~ o$ ~he bolt~ and end connectors by way o
cone ~urface~ at the end connector and a pres~ure bol-t or
separate ring tension element~0
The re~uired great frictional force 9 however9 may also be
applied by ~imple contac~ pressure between face~ in parallel .
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with the axisO
In accordance with an alternative embodiment of the invention
at least one recess or depre~sion is provided for this purpose 7
distributed around the circumferential ~urface, in the area
o~ contact of the bolt and/or connector link.
This recess or these recesses form spaces which will take up
lubricant from between the contact faces or extraneous matter,
such as dust and dirt ~queezed out by the clamping action so
that any foreign matter will be removed from the contact surfaces.
This makes it possible to realize in reproducible manner the
greatest possible coefficient or friction which is predetermined
by the materials of the bolt and the connector link.. :. .
As the frictional force transmitted is proportional to the co-
efficie~t of friction and to the clamping force, the design
according to the i~vention afford~ the greatestpos~ible ~rictiona~
force at any g~ven olamping force.
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The recesses may be provided either at the bolt or in the
respecti~e openings o~ the end connectorst or in both. r~hey
may be embodied9 ~or instance~ by longitudinal or
helical groo~es in the manner o~ a coarse thread~ the tip~ o~
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the flank~ of the thread being cut of~so as to provide the
contact surface bet~een the courses of the thread. ~urthermore
the recesses or depressions may be formed by milling or lunurling~
e.gO cross hatchingO If longitudinal grooves are chos~,they
should pr~ferably be machined in the end connector opening3
since this allows simple and inexpensive manufacture by broaching
or similar removal technique~O
Preferably either the bolt ends or the openings in the connector
links should be provided with the receRses because this is ~implex .
in production, affords clear contact surfaces, and fulfills the
purpose of keeping the contact surfaces free of lubricant and
foreign matter9 respectivelyg to full satisfac~ionO
Overload protection against undue stressing of the bolts which
may occur9 for instance9 when the bolts are bent by the chain
traction or when driving over uneven ground, can be obtained in
accordance with another modification of the invention by designing
the æecuring means against axial slippage such that a defined
axial slipping between bolt end and end connector ~ against.a
defined force, e g. of a separate spring i~ permitted up to a
stop or abutment.
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The invention will be described further, by wa~ of example,
:. with xeference to the accompa~ing drawings which show different
embod~ment~ and in which: .
~'ig. 1 is a perspective elevational view of a piece of a
~ . connector link chain inoluding tubular bodies and
- connector links dimensioned acoording to the invention,
. fig. 2 is a sectional elevation~ to an enlarged scale, along
line II-II o~ fig. 1 e~tending along a bolt and showing
: the assem.bly in a condition not sub~ected to bending
~ ~tres~,
fig. 3 is a view similar to ~ig. Z, yet not in section, of a
chain link in a po~i-tion above a groove in the ground,
fig~ 4 i8 an elevat~onal view, to an enlarged scale~ of a
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connector link and parts of the chain link, a~ seenin the directio~ of arrow A of fig. 1~
fig~ 5 is a perspective view of a piece of a connector link
chain according to another em~odiment of the invention,
fig. 6 ~8 a longitudlnal ~ectional view of a bolt along lin~
VI VI of figo 5~
~igo 7 is a graph demonstrating the bending load P~~othet~heain
vertical flexure ~ of the chain link,
figo 8 is a sectional view of a connection between the bolt
ends and an end connector according to the invention9
figo 9 is a top plan view of the connection shown in fig. 8,
~ig~ 10 i8 a sectional view taken along line X-X in figo 8
with a bolt omitted~
figo 11 is a sectional view similar to fig. 8 showing a modified
connection according to the invention~
~;lg~ 12 i~ ~ p~l~pe~ve exploded view o;~ a~ end ~on~e~t~r ~nd.
-~ a wedge piece of another modified connection according
to the in~ention,~ I
figo 13 is a top plan view of a connection using the elements
shown in fig. 12,
~igo 14 is a sectional view ~imilar to fig~ 8 showing anothex
connection according to the invention,
figo 15 is a perspective view o~ a member of the connection
shown in fig. 14~
fig. 16 is a ~ectional view similar to fig. 8 ~howing a
further embodiment of connections according to the
invention additionally illustrating a bolt end adapted
to the respective connection,
~igs. 17 to 20 are sectional view~ of bolt ends Of further
embodiments of connections according to the invention,
fig. ~21 is a sectional view, tran~versely of the bolt ends, of
a corresponding end connector,
fig. 22 is a secti~nal view taken along line XXII-XXII in
fig~ 23 of another connection according to the
invention
fi~. 23 is a 6ectional view taken along line XXIII-XXIII in
fig. 2a,
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fig. 24 is a part sectional view of a bolt end as example of
a friction-lock connection according to the invention
fig. 25 is an exploded view of the bolt end and a sectional
view of the bore of an end connector of bayonet con-
nection according to the invention9
figs. 26 and 27 are a sectional and top plan view, partly
sectioned, of another connection according to the
invention,
fi~. 28 is a perspective exploded view of an end connector
and two bolt ends of different design with recesse~
according to the invention,
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fig. 29 is a perspective exploded view of an end connector,
the openings of which are provided with recesses
according to the invention9 and of a corresponding
bolt.
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In each chain link-the connector link chain shown ~n fi~. 1
comprises two tubular bodie~.1 with running pads 2 at their
underside~ two end connector links 3 at either side of the
chain, and an intermediate connector link 5 with a chain tooth
4 guiding the vehicle by means of the .~.read rollers 12 which
roll-off the plane roll-off surfaces 11 of the tubular boaies 1.
~ach chain li~ generally designated 7 is connec.ted to the
successi~e chain link 7 through the connector links ~, 5 by
means of bolts ~ which extend through the connector links and
the tubular bodiesO
In the axea in which bolt 8 passes through the tubular bodies 1
a plurality of rubber sleeve~ 9 which have an excess dimension
as compared to through bores 10 in the tubular bodies 1 ar0
fixed on the bolts by vulcanization. ~ogether with their ~ubber
sleeves 9 fixed by vulcanization the bolts ~ are pressed into
the through bores 10, As the rubber ~leeves are capable of
.twisting, they permit tilting of the bolts 8 in the through
bores 10 by the angles neceesary for turning of the ch~in.
~he tubular bodie~ 1 and the connector link.s ~ 5 are accurately
dimensioned in a direction transversely of the direction of
movemènt C of the chain so that accurate clearance a within
manufaoturing tolerances is obtained between the tubular bodies :
and the connec-tor links when the chain links are not ~ubjected
to vertical bending load. . :
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When a ~ehicle equipped with the caterpillar,track according
to fig~o 1 and 2 drive~ over a rut or groove H in the ground
(fig. 3)9 the bolts.~ deflect in the manner shown exaggeratedly
in fig. 3. Beginning with a degree of flexure which can be
predetermined the clearance a i~ cancelled in the upper zone at/ ~ ;
locations : .
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x because of the bending deformation so that upon further
increase of the bending load the tubular bodie~ 1 and the
connector links 3~ 5 constitute a supporting bridge which
contributes to taking up the bending stress~ and relieves
the bolts of bending. r~he end connector links 3 are retained
on the ends 13, 1~ of bolt 8 not only against rotation but al~o
against longitudinal displacement in order to prevent these
ends 13 7 14 of the bolt 8 from slipping inwardly of the end
connector link~ 3 in the loaded condition shown in fig. 3.
. For this purpose -the ende 13 9 14 of bolts 8 are provided with
flat sections 15, 16 which cooperate with corresponding flat
sections in the end connector links, as shown in figs. 2 and 4.
~t the left end, as seen in figure 2, these flat sections 15
extend obli~uely with respect to the longitudinal axis of the
bol~ ~o ~ha~ ~h~ end aonne~.~o~ ar~ held under wedging ~ction
i.e. in form lock against slipping of the bolts inwardly. ~his
guarantees that the bolt ends are securely held, which are thus
expanded in their longitudinal extension upon further increase
of the bending stress,
However~ it showed~ that even with flat section~ 16 extending
parallel to the long~tudinal axis of the bolts, such as ~hown
for the right end 14 of the bolt, as seen in the drawing,
sufficient force can be applied merely by friction-lock
establishing contact pressure of the corresponding flat section~
of the connector link 3 to prevent the bolts from slipping out, . .
provided corxesponding measures are taken, e.g..tho~e illustrated
in figs. 28 and 29 and explained in the description of those
. figure~O
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- In practice, of course, for reasons of economy preferably
either the left or the right alternati~e shown in figure 2
or one of the other alternatives descrlbed belo~ is ~elected
to xeal~ze the flat sectio~s at both bolt end~9 depending on
. the respective use o~ the ~hain.
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~he one-piece end connector links 3 have a slit 17 merging
a~ either end into through bores 18 which serve to recei~e the
bolt ends 13 and 14 9 respectively~ and being enclosed all around~
As may be taken from ~igure 49 the two opposed material bridges
19 9 20 at ei*her side of ~lit 17 can be contracted by means of
a screw 210 Hereby the contact pressure can be produced which
is required to preas the flat sections in through bores 18
against the fla~ ~ections 15~ 16 of bolt ends 1~ 14.
The end connector links ~ may also be divided in longitudinal
direction.
It is also possible to provide a greater even number of tubular
bodie~ 1 for each chain link instead of only two~ In that case~
apart from the center which again contains an intermediate
connecto~ k 5 pxovided with a chain taot~ 41 intermediatc
connector links similar to the end connector links 3 are
inserted between the individual tubular bodies. ~hese inter
mediate connector links have surfaces which are flush with
the sur~aces 11 of the tubular bodies to increase the roll-of
surface for the correspondingly wider tread rollers, thus
contributing to improve the smooth running. When it is desired
to enlarge the chain, this type of structure i~ preferred in
that it of~ers more convenient storage and savings of weight and
mate~ial as compared to a structure employ~ng wider structural
elements, especially wider tubular bodies. It is to be under-
stood that even with such a wider chain having a correspondingly
greater number of tubular bodies and connector links~ these
elementæ are accurately dimensioned in a direction transversely
of the running direction of the chain so that~ beginning with a
predetermined ~le~ure~ the tubular bodies and the connector links
support each other and again form a bridge protecting the bolts
from excessi~e bending stress.
Figure 5 likewise ~hows an embodiment o~ a chain which is
wider than the embodiment according to figure 1 but which
comprises three tubular bodies~ in other word3 an uneven number
o~ tubular bodies per chain linkO Just like the tubular bodie~
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1 the tubular bodie~, designated in general by reference
numeral 41, have through bores 42 to receive boltr 44 provided
with rubber sleeves 43 which are fixed on the bolts by vul-
canization. In this case the rubber sleeves mentioned are also
provided in a central tubular body 41 which carries a chain
tooth 60. On principle the bOltsa 44 are of the same structure
as bolts B of the embodiment shown in figures1 to4 .In thi3
case~ too~ measures are taken to secure the bolt ends 47 and
the end connectors 48 against relative rotation and axial
slipping~
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~he embodiment according to figure-a. 5,6 compr.ises divided
intermediate connector links 55 o~ which only the upper part
is to be seen. The lower p æt is adapted to be clamped agains~
the upper par~ and at the same time a~ain$t the bolts 44 by
means o~ ~crews 56. ~he parts of the lntermed~ate connectors
55 together form recesses or openings which, in assembled
condition, surround approximately three quarters of the total
circumference of the bolts in the areas 54 in which they are
free of the rubber sleeves 53. The intermediate connector
links may have areas 57 which extend trans~er~ely of the
running direction of the chain between adjacent tubular bodies
41 and form a flush surface with the surfaces 58 of the tubula~
bodies 41~ But satisfactory sm~thhr~nning can be obtained also
without such area~ 57. ~ikewise ~ith these surfaces 58 i8. the
surface of webs 59 which extend from the central tubular bodies
41 toward both sides to the ~acent tubular bodie~ 41 trans-
ver~ely of the running direction of the chain~ These webs 59 do
not reach as far a~ the overall dimension of the tubular bodie~
41 in the running direction of the chain but instead leave
spaces into which extend webs 61 provided at intermediate
connector links 55 and oriented in running direction and in
a direction opposed to the same~ respectively~
~he dimensio~ o~ web~ 59 at central tubular body 41 and of
web~ 57 and ~1 at intermecliate connectors 55 (to be seen only
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in figure 5 bu-t not in figure 6) as well as the dimensions of
the outer tubular bodies 41 and of the end connector link~ 48
in a direc-tion transversely of the running direction of the
chain are ~o selected that again a predetermined clearance a
is obtained which, in the present case, is zero~ By vir-tue o~
this arrangement, upon vertical de~lection the bolts 44 are
partly relieved from the very beginning from bending stxess.
Structural elements such as sho~n in figure 5 can also be used
to make wider chains with a greater uneven number o~ tubular -
bodies per chain link.
Figure 7 shows the course o~ a bending load P of the chcin above t
bending flexure f of a chain link such as shown in ~igures 1 to
3 or 5 and 6. ;
The continuous curve k represents-the course of the loading
above the deformation, starting from a finite clearance a
(figure 2). When a flexure fl or a bending load Pl is reached,
the tubular bodies have come to abut each other or the
intermediate connector links and form a stif~ening bridge~ ~he `-
continuous curve k then bends at k1 and continues more steeply.
~his means that a greater bending force must be applied to
obtain the same deformation, in other words that the chain
link as a whole has become stiffer. Curve ko is a discontimlous
line showing how the load-deformation-characteristic would
continue i~ the bolt were deformed alone without support by
the elements of the chain linkO Curve ko would soon get into
ranges where the deformation would be too great. If
one considers that in the range of higher load it is predominantly
the tubular bodies and the connector links~ and only partly the
bolts~ which have to withstand bending stress, it is evident
that the bolt may be made to smaller dimensions at the same
~otàl load than i~ the bolt alone also had to endure maximum
bending stresse~. Accordingly, also the through bores 10 and
~29 respeotively~ in the tubular bod~es and the bolt recei~ing
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bores 18 in the end connector links may be made to smallerdimensions, which in turn entails a reduction in ~ize and weight
of thetubul~.r bodies ~s well as the co~mector links.
The dash-dotted line in figure 7 shows the course of a curve
l which is obtained when the clearance a is ~ero from the
very beginning (figure 6). In this case the tubular bodies and
the connector links support bending loads together with the
bolt from the very beginning~
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In figures 8 to 27 a one-piec~end connector is designated 1000
The end connector 100 has two essentially circular through
bores 101, 102 which are connected by a slit 10~ This slit
103 ~ubdivides the end connector,which is either made in one .
piece (fiK.12)or divided ~fi~.16),into twn bridges 106,1074
In the embodiments shown in figures 8to1.3a central hole or
opening 108 of the end connector receives a fitting pieceO
This fitting piece is embo~ed by a round bushing 109 in figures
8.to11.The bushing 109 has flat sections 110 at its two
opposed sides ~acing the bolt ends 104~ 1050 These flat sections
are inclined in two directions (s~ figure~ 8 and 9) and co-
operate with corresponding flat sections 1 l 1 at the bolt ends.
~he bushing 109 is pressed against the flat sections 111 of
the bolt ends b~means of a central screw or bolt 1120 The flat
sections may also be inclined in one direction onl.y or may not
be inclined at all, iOe. they may extend completely parallel
to the axis~ The mai~ difference between the embodiments
shown in figures~to1Oand 11 resides in the fact that figure 8
shows the bushing 109 to have a threaded bore 113 into which
enters screw 112, whereas with the embodiment shown in figure
11 screw i12 is inserted in a plain hole 114 and screwed into
a threaded bore 115 in the bridge 106 of the end connector.
The contours of the flat 6ection 110 (discontinuous line,)
of bushing 109 and of flat ~ection 111 at the bolt end
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(continuous line ~ are sho~m in figure 10~ q'he two 1at
sections contact each other in the cross-hatched area of
profile 110,
The embodiment according to figure 12 dif~er~ only by an an-
gular~ fitting piece 116 instead o~ the round bushing 109
fitted in a corresponding angular hole 117 in -the end connec-
tor 100. The angular fitting piece also has flat sections 110
at both sides 9 inclined in two directions and facing the.bolt
ends 104, 105. ~y these 1at sections it is pressed against
corresponding flat sections at the bolt end~, using a screw
112 not shown in figure 12. ~he flat sections may also be
inclined in one.direction only (see figure 11)o In a view
similar to figure 13 this fitting piece would look re.ctangular,
having edges 110 in parallel with ~he axis (figure 5).
A form-lock connection between the bolt ends 104, 105 and the
end connectors 100 i~ achieved with the ~itting piece 109 and 1
116, re~pectivelyO ~his connection prevents axial displacement
as well as rotation.
In the case of a connection according to figure 14 the two
bridges 106, 107 of the end connector are tightened against
each other by means of a central screw 120. A disc 122 is
arranged between the head 121 of the scr~3and the surface of
the bridge 107. Cylindrical ~itting pins/extend do~nwardly from
the disc (figure 15). These cylindrical fitting pins are
arran~ed such that they extend through corresponding recesses
124 in the bolt end~O
It is also possible to provide conical pins
instead of cylindrical fitting pins 12'~. ~urthermore~ the disc
122 need not be firml~ connected with the fitting pins but
instead may form a ~eparate element which merely cooperates
in ~orce-lock with the end faces o~ the fitting pinsO
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Also only one fitting pin per connector 100 may be T1rovided.
Instead of providing a separate fitting pin the clamping bolt
itself may h~ve a fitJting portion fulfilling the function of a
fitting pin for one or both bolts.
Figure 1f, shows the end connector in divided form, the two parts
133,134 thereof being pressed against each other and against the
bolt ends by means of a central screw 120. The bolt ends ~gain are
provided with flat sections 135, either at diametrically opposed
locations or in V-shape at one side (not shown). Corre~ponding
flat sections 136 provided at the end connector parts cooperate
in form-lock with those flat sections.
r~he screw connections of the embodiments according to fi~llres
17 and 18 comprise ~crew connections in the direction of t~le
longi-tudinal axi9 of bolt ends 104 and/or 105 to secure the bol1s
ag~ln~t axiAl di~pl~cemen~. 'l'he conne¢~ion accor~ing to rlgure 17
shows a screw 137 which is screwed into a threaded bore in t'ne
bolt end coaxial with the longitudinal axis of the bolt, the
head 138 of this screw being ~ported on the end connector 100 -,
through a disc 139. The disc 139 may be replaced by a spring, e.g~
a pile of ~elleville washers which permits a defined axial dis-
placement of the bolt end 104 with respect to the end connector
1~0. The defined axial displacement is determined by the maxi.~um
deflection of the spring. Instead of separat~ sprîngs the elastic
expansion of the screw 137 itself may slso be utilized. For this
purpose the screw may also be designed a's a highly deformable
bolt having a weakened shaft.
With the modification according to figure 18 a threaded pin 140
which is coaxial with the bolt axis projects ~rom the, front face
of thebolt end 104. A nut 141 i9 screwed on this pin 140 and its
axial force is supported at the end connector 1~0 by way of a
spring or disc 139. No mean~ ~ seauring the connection ~ainst
rotation is shown in figures 17 and 18. It may be obtained in
the usual manner by flat sectlons parallel to the axis at the
~2~4
end~ and
bol~ end connectors. In thi~, case, however, the flat sections at
the bolt ends extend up to the front faces of the bolts.
'~he form-lock connections according to figures 19 and 20 are
obtained by ~ressing end connector material into depressions
of the bolt ends.
The connection according to figure 19 shows the bolt end to
have two hollow fillets 142, 143 inclined in opposite directions,
between which a web 144 was left. Material of opposite areas of
the recess for the bolt ends or of the bridge members 10~),107, '
respectively, is pressed under elastic deformation into the
hollow fillets 142, 143 by the central screw 120 clamping the '
bridge-members 106,107 so th~t a form-lock connection is e~tab-
lished. '~hen screw 120 is unscrewed the material ela~tically re-
turns in its undeformed shape which renders possible disassembl- '
in~ ~f th~ bol~ from th~ oonn~tor.
The embodiment accordintg to figure 2~ shows three hollow fillets
145 having saw-tooth profile at the bolt ends~ Projections
146 of corresponding outline are formed in the openings in
the end connectors 1000 The gap 147 between the hollow fillets
145~and the projections 146 is shown exaggeratedO In an
actual embodiment it is in the range ~rom one to two
hundredths of the bolt diameter and so dimensioned that in
unloaded condition of the connector the bolt may be pushed
into the opening. Then the screw 120 is tightened so that
the projections 146 are pressed into the depressions of the
hollow fillets 145 9 thus providing'a form-lock connection~
~he end connector used for the connection according to figures
19 and 2~ has a cross sectional shape such as shown in figure 21.
With the connection shown in figures ~? and 2~ axial fixing ~ ;
in one direction and rotatory ~ixing .i6 provided by a clamp ; ' ''
180 a~sociated with each bolt end. The legs 181 of the clamp
~ngage in diametrically oppo~ed flat sections 182 at the
respective bolt. ~he clamp 180 supports an axial force on the
bolt in inward direct~on (in figure 23 directed up~vardly) at
the front face 183 of a tubular body 184 of the track facing
the end connectorO Rotation of the clamps 180 and thus of the
.. , . . - , ., ~ . .
19
_
connector
bolts is prevented by projec-ting wall portions 185 of the end/
If a similar connection is provided at the upper bolt end~ 9
axial slipping of the bolts with respect to the tubular bodies :.
184 and thue the end co~nectors i~ prevented in both directions.
With the embodiment.. according to figure. 24 the connection
between the end connector 100 and the bolt end~ 104 and 105
respectively~ is realized by friction lock at a ~ery great
frictional forceO . . Wedging action i8 utilized for
this purpose~ a relati~ely small ~oxce produced by a screwed
connection in axial direction being converted by a wedge
surface into a great normal force which in turn produces a
great frictional force. . -~
~onical ~urYaces 195~ 196 at. the end connector and at the inner - .
end, réspectively, of a hollow screw 197 cooperate to produce
contact pressure between a bore fitting piece 198 and the bolt
circumference along a circumferential area shown by cross hatching~
.: ' ;
h~igure 25 shows an example of a bayonet connection between a
bolt end and an end connector.
,
The bolt shown in fig. 25 has axially directed wedge teeth 204
at its end. ~orresponding wedge teeth 206 are formed in the
.opening in the end connector to fit into the wed~e ~aps 205
: between the wedge teeth 20~. Axially adjacent the wedge teeth 204
the bolt has a portion 207 of reduced diameter which is separated
. ~y a shoulder 208 from the`main portion 209 of the bolt having
~a diameter corresponding to the diameter of the tops of teeth 204.
.
By inserting the bolt in the direction of the arrow against
shoulder 208 and subsequent rotation the wedge teeth 206 are
caused to engage behind the wedge teeth 204 so as to secure
the bolt against axial displacement in both directions.
,
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-- 20 --
In the embodiment according to Iigures 26 and 27 the bolt end~
104, 105 are provided at opposed circwnferential area~ with
- transverse grooves 2209 221 into which enter opposed pro~ections
223~ 224 of a disc 225. The disc is so dimensioned that it ~,
~its into the slit 103 in the end connector 1000 The disc 225
has a central aperture 226 for insertion of the central screw
120 which ser~es to clamp the bridges 106, 107 of the end
connector 1000
~he dash-dot line at 227 show~ a tongue which may be pro~ided
additionall;y at the disc 225 to facilitate the sliding on of the
- end connector 100. ~his provides a form-lock connection which
affords rotary securing as well as axial fixing in both
directions without any measures being taken at the end
connector 1000 Thus a conventional end connec tor can be usedO
In addition, only the diso 225 and the grooving of the bolt ,
end~ a~ quix~d. F~ thi~ r~a~on th~ ,emb~di~nt ~ocordin~5
to figures 2~ and 27 is especially economicalO
~he end connector 301 shovm in figure 28, is made in one pieceO
It has a~ elongat,ed through opening 302 , the end~ of ~r~hich .
are widened to form recesse~ or opening~3 ~03 to receive bolts
304.... The rece'~ses are adapted in shape to the bolt ends in that ,,'
they have a hollow cylindricali portion 305 extending over the
major pisxt of the circum~erence and a flattened portion 3060
The bolts are formed accordingly with a cylindrical portion ' "',''3059 and a flattened por~ion 306'. ~he recesses are machined
to .correspond to the bolt ends.
~he two bridge members 307~ 308 in the central portion of ~he , - ' :
connector may.be forced. against each other by a clamping screw
which-i~ not shown and adapted to be in~erted in through holes
3,09, 310 in the two bridge members and tightened by a lock nut
',likewi'sè not showIl. Alternatively the hole 310 ln bridge membex
308 mi~y be designed a8 a threaded hole"
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.. ,... . ~ . .. . . . . ........ .. . .. . . . . .
.
. - 21 _
While t~le openin~s 303 of the connector 301 have a ~moot}.
surface~ longitudinal grooves 312 of a length extendlng acros~
the width of the connector are machined into the ~l~ shown on
the left in figure ~,Surface portions or lands 313 remain
between the longitudinal grooves, 312 and with the bolt installed
they are in contact with the smooth surface ~05, 306 of the
opening 303O
Instead o~ longitudinal grooves the bolt shown on the right
hand side in figure 28has a plurality of helical grooves 314 ~-
at the bolt end cooperating with the opening~ Again contac-t
surfaces 315 between the grooves 314 cooperate with the smooth
surface 305, ~06 of the opening. It is also possible to provide
a single.groove 314 which will have a corrsspondingly low pitcho
In the embodiment ~hown i~ figure 29 the bolt ends have ~
smooth ~ylindrical surface 316' and smooth flattened portion~ 317' !
whereas the openings 30~ have longitudinal grooves 322 and raised
contact surfaces 323 between the grooves ~22 as well in their
cylindrical portions 316 as in their flattened portions 317 for
cooperation with the bolt surface. ~he longitudinal grooves 322
can be produced by broaching in easier and less expensive'
manner than longitudinal grooves 312 on the Quter surface o~
the bolt 304 in fiq. 28.
In the case o the connections a`ccording to figures 28 and 2g
the tightening of the screw produces a clamping force which acts
vertically of the contact surfaces and has a higher specific
surface loading than with smooth contact surfacesO ~his clamping
force presses residual lubricant and any possible foreign matter
from be,tween the contact surfaces into the grooves 312, 314 or
322 so ~hat the greatest possible coefficient of friction
determined by the pairing of material of the bolt and the
connector 301 prevails between the contact surfaces~ If the
grooves were not provided~ it would be una~oidable
that lubricant or foreign part~cles remain between the~con~act
surfaces thus changing the coefficient of friction; and ~onse-
quently the required clamping force in un~redictable mannerO
This i~ notonly due to the lacking space for evasion of
undesired matter but also to the fact that the specific surface
loading obtained by the same 9crew tlghtening torque is smaller~
... . .. . ..... I . .. . - . . . - -
~ S4
- 22 -
It is convenient to select the width of the longitudinal grooves
312, 322. or of the helical grooves 314 and the spacin~
defin.ing their contact surfaces ~1~ an3d 315~ respectively7
such that the specific pressura at the contact surfaceis is
sl~ghtly below the flow limit of the materials of bolts and
end connectorsO
Axial displacement between the bolts and the end connectors
is prevented by a connection according to figures 8to 29 or9at
the mQst9 possible in controlled manner against spring force
up to an abutment. Thiis type of connection permitting controlled
displacement between the end connector~ and the bolt endis has`
been explained only in connection with figuresl7 and 18,Yet it
is obvious to anyone 6killed in the art that all other embodi- :
ments may also comprise additional springs or may have sufficient
inherent resiliency of the boltis to permit controlled axial
relative movement between the bolt ends and the end connectorsO
' , I ,. .....
It is also evident that. a connection according to figures 8 to
..29, may also be useful with a caterpillar track in which the
support of the tubular bodies 1 and the connector links 3~ 5
:~ explained with the aid of figures 1to7. iB not embodied or~ in -
other words~ in which the parts 1, ~ and 5 may shift in
undefined manner transversely of the direction of mo~ement
of the caterpillar trackO.
The pre~ent embodiments are to be considered as in all respects
illu~trati~e and not restrictive; the scope of the invention . .
being indicated by the appended claImsO
,
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