RUBBER-MOUNTED PINS FOR CRAWLER TRACKS

CHEVILLES A MONTURE DE CAOUTCHOUC POUR CHENILLES

English Abstract

ABSTRACT
The durability of resiliently mounted pins for crawler tracks
having vulcanized rubber bushings pressed into a bore in the track link, is
increased by bonding the rubber rings to the wall of the hole bore by a
layer of adhesive. In place of the existing tubular material, namely steel,
and of the existing rubber bushings, it is possible to use other pairs of
materials having lower coefficients of friction than those used heretofore,
such as plastics, fibre-reinforced plastics, and non-ferrous metals for the
track links, and elastomers other than rubber for the resilient bushings.

Claims

THE EMBODIMENT OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A resiliently mounted pin, having vulcanized rubber bushings for
crawler tracks, which is pressed into a bore provided for such a pin in a
track link, wherein said rubber bushings are bonded without heating to the wall of said bore
by means of a layer of adhesive.
2. A resiliently mounted pin according to claim 1, wherein the layer
of adhesive consists of a cold curing vulcanizate or bonding agent.
3. A method for producing resilient bushings bonded into a bore in a
crawler track element and vulcanized to a pin, characterized by the
following steps:
1) the wall of the bore is degreased and the adhesive is
applied thereto;
2) the pin with the vulcanized rubber bushings is pressed
into the bore with the aid of a lubricant;
3) the track element fitted with the pin is stored for about
70 hours.

Description

11540S~
The invention relates to reslliently mounted pins for crawler tracks
having vulcanized rubber bushlngs.
In the case of resiliently mounted crawler tracks, the pins with
vulcanized rubber bushings are pressed into bores in the body of the track. As
the track travels on the running gear, the pins rotate in relation to the
tubular element. The torsional paths produce deformation of the rubber bush-
ings by torsional stress. Friction between the rubber bushings and the wall
of the bore of the tubular element prevents the bushings from slipping - cf.,
in this connection, the two-hinge-pin type crawler track according to German
Utility Model 19 05 877.
In the case of crawler tracks of the single hlnge-pin type according
to German OS 27 55 412, the angle of rotation ocurring as the track passes over
the deflecting wheel of the running gear is twice as large as in the case of
a track of the two-hinge-pin type. As a result of this, the friction present,
r ~ up to certain angle of rotation, bet~een the prestressed rubber bushings and
the wall of the bore in the tubular element is o~ercome, and the bushings slip.
This has the disadvantage of causing rapid wear of the bushings due to excessivefrictional heat and frictional wear, with increasing destruction of the struc-
ture o the rubber. The unprotected pln then begins to rub agalnst the bore,
2Q initiall~ against the edges of the bore in the tubular element ~steel against
,
steel), and this finall~ c~uses the pin to fail.
It is the purpose of the invention to prevent slipping of the pre-
i .
stressed rubber bushings as a result o the larger angles oP rotation arising
~, in tracks of the single hinge-pin type. It is urthermore a purpose of the
~i ` invention to increase the durability of the rubber mounting of the pins of
crawler tracks, especiall~ in the case of tracks of the two-hinge-pin type.
This purpose is achieved by bonding the rubber bushings to the wall
of the bore b~ means of a la~er of adhesive. The advantage of this is that~a
. "
.
, .
-' ~
. ` ~: . : . '
' ~

" ~15~05S
non-slip arrangement of the bushings is obtained when the material now used for
the tubular element, namely steel, and the rubber now used for the bushings are
replaced by other pairs of materials, for example plastics, fibre-reinforced
plastics and non-ferrous metals, for the tracks and elastomers other than rubberfor the bushings. It is therefore significant that, according to the invention,
it is possible to use pairs o~ material having lower coefficients of friction
than heretofore.
The invention provides a resilientl~ mounted pin, having vulcanized
rubber bushings, for crawler tracks, which is pressed into a bore provided for
~J t/ o~J f h~t`~7'",~,
B lo such a pin in a track link, wherein said rubber bushings are bondedlto the wall
of said bore by means of a la~er of adhesive.
The invention also provides a method for producing resilient bushings
bonded into a bore in a crawler track element and vulcanized to a pin, chara-
cterized by the following steps:
1~ the wall of the bore is degreased and the adhesive is applied
thereto;
2~ the pin with the vulcanized rubber bushings is pressed into the
~ore with the aid of a lubricant;
3~ the track element fitted with the pin is stored for about 70 hours.
An embodiment of the invention is illustrated by way of example only,
in the drawing attached hereto, wherein:
Figure 1 shows a partially sectloned simplified detail of a crawler
track according to the single hinge-pin principle;
Figure 2 shows detail A in Figure 1 to an enlarged scale;
Figure 3 shows a pin equipped with rubber rings being pressed into
the hore in body of the track.
According to Figure 1 a maximal angle of rotation 3 exists between
two crawler track links 1, 2 as it rotates about the deflector-wheel ~not
~, ~
~ -2`
.
~ . . - .
. . .
.
.

liS4(~5S
shown). In the follo~ing description of the connecting parts for these links
1 J 2 such as cams and clamp fittings, only one connecting part is described.
Many connecting parts of this kind are provided, the number thereof being gov-
erned by, among other things, the tensile force to be transmitted by the track.
Integral with the ends of track links 1, 2 are lugs 4, 5 ~o which a
clamp fitting 10 is secured by a threaded fastener 11, 12. Clamp fitting 10
grips the free end 13, 14 of the pin shown in Figure 3. Other steps, of which
no further mention is made here, are taken to ensure that clamp fitting 10 is
secured positively and frictionally to pin 15 and that track links 1, 2 track
correctly. Rubber bushings 20-23 are vulcanized to the pin. A layer of ad-
hesive 26 ~see Figure 2) ensures that the bushings adhere to the wall 24 of bore
25, the free diameter 35 of the said bushings being larger than the diameter 36
of said bore. The rubber bushings are deformed as they are pressed into the
bore, in such a manner that spaces 37, 37' ~Figure 3) between the bushings are
filled, and the bushings are prestressed.
As shown in Figure 2, the layer of adhesive 26 is applied to wall 24
of tubular element l. The adhesive may be a one- or two-component material,
such as a cold curing vulcanizate or bonding agent known per se.
Figure 3 illustrates the steps required to secure the bushings 23-23
against rotation in the bore 25 in track link 1.
1) Bore 25 is degreased and a layer of adhesive 26 is applied thereto.
2) Pin 15, with vulcanized rubber bushings 20-23 is pressed into
bore 25 with the aid oE a lubricant (not shown) lntroduced in the direction of
the arrow 31, the lubricant being an oil compatible with rubber.
3) After the pin 15 has been inserted, the track links 1, 2 are
stored for about 70 hours at room temperature, while the reaction takes place
between the layer of adhesive and the rubber bushings.

-` 115~ 5S
This bonding of the rubber bushings into the bores in the track
links is readil~ applicable to spring-elements subjected to torsion or thrust~
preferabl~ to spring-elements, the rubbers of which are prestressed between
metal parts. An example of this is the spring-element used in the vicinity
of the rear-axle of an automotive vehicle.
.
.
_~_
, :.. ,.. ~ .
''