Performance Statement
Quickhitches have revolutionised the application of
hydraulic excavators making them by far the most
versatile piece of plant available to the
earthmover. Fitting a hydraulic quickhitch to your
excavator means the right tool can be used for the
job because the time to change most implements is
less than one minute. Previously, the operator was
required to remove both pins from the excavator and
try to line the bucket pin holes with both excavator
pin holes, then insert the pins and secure them.
This was a long and tedious process.
There are four main types of excavator quickhitch:
Half or Pull pin Quickhitch
Spring Quickhitch
Mechanical or Screw Quickhitch
Hydraulic Quickhitch
Whilst there are these four main categories of
quickhitch – the main differences between them are
the way they engage the rear bucket pin. The basic
body style is very similar with all four hitches.
You may ask why would there be so many different
types of Quickhitches available? The answer is
basically, price and preference, hydraulic
Quickhitches are the desired type of quickhitch for
most operators, however the hydraulic cylinder used
to operate the tongue of the hydraulic quickhitch is
quite expensive and the various hydraulic pipes and
switches and valves required to run the quickhitch
are quite expensive to install. Generally, most
excavators over 8 tonnes in operating weight will
require a hydraulic quickhitch to be fitted.
Half hitch or Pull Pin Quickhitch
The half hitch is designed for small or mini
excavators and they are designed with a yolk that
fits under the front pin of the excavator bucket.
The bucket can then be lifted so that the rear pin
hole of the bucket aligns with the rear pin hole in
the quickhitch, then a removable pin is inserted
into these holes ensuring the bucket is attached to
the quickhitch by both front and rear pins. A safety
pin is then inserted to lock the pin to ensure it
does not loosen, and the bucket is ready for work.
This type of quickhitch is recommended only for
small excavators, as the buckets are reasonably
light and manoeuvrable.
Spring Quickhitch
The Spring quickhitch is a semi automatic quickhitch
that when the front pin is engaged the quickhitch
can be lowered onto the rear pin, where it
automatically connects through the spring mechanism
once the bucket pin is located. The operator only
needs then to insert the safety pin to ensure the
pin does not disengage the spring under load or
stress. This type of quickhitch is often used on
excavators up to 5 tonnes in operating weight.
Mechanical or Screw Hitch
The mechanical quickhitch simply uses a long screw
to slide a steel tongue under the rear bucket pin to
engage it. The screw is mounted in a convenient
location on the front of the quickhitch and is
easily used with a speed brace or cordless drill. Of
course, there is a safety pin mechanism to ensure
the screw drive does not loosen under load. The
Mechanical Quickhitch is usually used on excavators
under 8 tonnes in operating weight.
Hydraulic Quickhitch
The hydraulic quickhitch is the most preferred
quickhitch, and is used on excavators from 3 tonnes
to 160 tonnes in operating weight. These
Quickhitches have the tongue driven by a hydraulic
cylinder to ensure the rear pin engages. There are
numerous safety mechanisms available for the
hydraulic quickhitch to ensure safety is paramount.
Unfortunately, there have been some accidents in the
past which have heightened the area of safety
awareness. Once a bucket is fully loaded with
material, should it become detached from the
machine, it can have dire consequences for anyone or
anything around the area, especially if working on a
slope.
Because of this reason, it is imperative that the
safety pin be engaged at all times on the quickhitch
to ensure, for any reason at all, the bucket cannot
be dislodged from the excavator unless the operator
intends it.
All our hydraulic hitches are designed with a check
valve in the hydraulic cylinder to ensure, should
there be a hydraulic failure within the excavator,
the pressure is equalised between the flow in and
out ports to ensure that the cylinder will not open
and drop the bucket.
We are currently working on an auto-locking system
which will rely on a system other than hydraulic to
act as a tertiary locking system, to replace the
manual safety pin mechanism. Obviously, until the
many trials are completed, we will not be
introducing our auto locking mechanism to the
market.
Quickhitch Design
The challenges facing our engineering team when
designing our superior hydraulic quickhitch, were to
design a quickhitch that was safe, robust and
compact without losing any of its flexibility or
performance.
Any extension of the dipper arm adversely affects
the excavators lifting capacity as well as digging
performance, which in turn affects the capacity of
the bucket, it is of utmost importance that the
quickhitch is the most compact design available. The
following table shows the impact of compact vs.
non-compact quickhitches on bucket lifting
capacities.
|
Machine Operating Weight |
Compact Quickhitch |
Normal Quickhitch |
|
|
Height |
Allowable Load |
Height |
Allowable Load |
|
3 Tonne Excavator |
|
|
|
|
|
4 Tonne |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
User safety is paramount in the design and
construction of the Quick hitch. The heart of the
safety features is the hydraulic cylinder
Safety features: Safety pins are incorporated as
part of the hitch assembly.
Hydraulic circuit: in the cylinder assembly closed
and the operated locking valve is incorporated into
the cylinder body. The hitch will not disengage if
there is a drop in hydraulic pressure or a burst
hose
Our breakthrough design offers a 100% Bisalloy
quickhitch that will withstand any tough working
environments, that is compact so that the excavator
performs at its maximum.
|
