Berco
has given priority to the significant requirement of reducing pin and
bushing friction wear in their chains.
These components, track bushings in particular, are of fundamental
importance to chain durability and are therefore manufactured by Berco on
the basis of a specific integral process using the most modern design and
production systems.
Track bushings have a surface hardness of Rockwell C 60, a case depth
hardness of Rockwell C 50 (from 1.5 to 3.5 mm depending on size), tempered
ends (depending on chain type) and a core hardness of Rockwell C 40. Track
pins have a surface hardness of Rockwell C 60 and a case depth hardness of
Rockwell C 50 (from 2.5 to 7 mm depending of size).
PINS AND BUSHINGS
Berco has given priority to the
significant requirement of reducing pin and bushing friction wear in their
chains.
These components, track bushings in particular, are of fundamental
importance to chain durability and are therefore manufactured by Berco on
the basis of a specific integral process using the most modern design and
production systems.
Track bushings have a surface hardness of Rockwell C 60, a case depth
hardness of Rockwell C 50 (from 1.5 to 3.5 mm depending on size), tempered
ends (depending on chain type) and a core hardness of Rockwell C 40. Track
pins have a surface hardness of Rockwell C 60 and a case depth hardness of
Rockwell C 50 (from 2.5 to 7 mm depending of size).
SEALGROUPS
This seal system, which
according to experience has proved to be the most advantageous, is used on
all the Berco “Sealed” chains. It consists of simple spring steel washers
of high hardness (Rockwell “C” 50) which, when compressed in the link
counterbore, assure a perfect seal. The limited thickness of these washers
allows an excellent matching of pin and bushings. On normally abrasive
grounds, this system increases the chain life by 20-30%.
SHAFTS
The alloy steel gives toughness
to the drop forged shafts. Precise final machining, performed with
sophisticated Flexible Manufacturing Systems (FMS), maintains a perfect
fit. Induction hardened surfaces in contact with bushings ( Rockwell C 60
), carefully machined, extend bushing life to a maximum.
TRACK BOLTS
All Berco bolts are forged, cup-headed
and roll-threaded, giving exceptional resistance to tensile stress as well
as longer life. Berco nuts fit the bolt holes perfectly, thus giving the
maximum grip, while their square shape makes assembly and disassembly
easier.
The mechanical characteristics
of Berco bolts correspond to grade 12.9 to European Specifications (unit
breaking load 1200 to 1400 N/sq.mm).
SEAL
Berco
seal groups are a result of many years of experience associated with the
production of undercarriage components. The combination of three
geometries and wide dimension ranges, two versions of sealing rings and
three different rubber compounds for the elastic rings, provide a complete
answer for sealing applications where rotation is involved.
The different geometries are named: "LT, "LL" and "IL".
The "LT" type has a load ring
with a torodal cross section and is recommended when the radial opening
for the seal is limited;
The "LL" type with its rhomboidal
cross section load ring has its application when the space in the axial
direction is limited;
The "IL" type with inverted rings
is particularly suitable for high rotation speed.
The sealing rings can be provided in standard version (coated alloy steel
rings with lapped mating surfaces and surface hardness Rockwell C 65) or
heavy duty version. The heavy duty version is made from special castings
with high percentage of chromium and molybdenum resistant to all types of
corrosion and oxidation. They are subjected to special heat treatment
processes in order to achieve the highest hardness values (Rockwell C 68),
optimizing, in this way, durability and wear resistance.
As far as rubber compound is concerned, three types are proposed by Berco:
standard, suitable for a temperature range from
-15°C up to 100°C (5°F up to 212°F);
semiarctic, for temperatures ranging from -40°C up
to 100°C (-40°F up to 212°F);
arctic, in case of extreme application
temperatures from -55°C up to 165°C (-67°F up to 329°F. In this case,
the load rings are made out of silicone rubber.
The Berco Technical Department is always ready to assist you with any
information regarding the application, installation or geometrical data
for its seals and all inquiries are encouraged and welcome.
