FIELD OF INVENTION
This invention relates to novel transport lock for tractor.
BACKGROUND OF INVENTION
Currently, transport lock is used (fig 1) in Farmtrac Tractor. Said transport
lock comprising of Knob for circuit on/off (K), Knob for Locking/Unlocking (L),
Tapping for External Hydraulics (T). This transport lock has dual usage, one for
re-routing oil from internal circuit of the tractor to the external circuit of the
trailer. Hence, oil is diverted externally through this manner as FT tractor
models don't have an external lever as present in Powertrac Tractor models,
where by turning the lever present on the quadrant lever assembly will cause
the oil to circulate in the internal or external system. This lever is called the
Circuit Lever marked by Red knob.
Secondly, the transport lock is used to maintain height of implement when the
tractor is carrying implement from the farmers home/ garage to the field and
vice versa (may be subjected to sealing system of cylinder). If this transport
lock is not used, the implement will come down to achieve stability under its
own weight, even though the cylinder and hydraulic lift is in lifting condition.
The weight of the implement causes compression of the oil in the cylinder;
thereby oil gets pressurized and tries to escape through seals and passages.
Therefore, the oil tries to escape thru the seal present in the piston or through
the return passage which includes the capsule of the unload valve and spool
valve i.e., via the bushing of the unload valve or spool valve.
With the leakage of the oil the implement slowly but steadily starts descending
down, but since the quadrant position lever is in lifting condition, the cylinder
again starts filing with oil. This causes the implement to come up again. This
up and down movement of the implement harms hydraulic system by breaking
or damaging components such as rocker, drafts linkages etc.
'
-3-
By introducing the transport lock, the number of places is reduced where the
oil can leak. Now, the only place left for the oil to leak is the piston and cylinder
sealing arrangement, hence, practically maintaining the implement at a
constant level.
The existing design 1s associated with several drawbacks that, the transport
knob is required to be turned at least 5 to 6 times for the transport lock to
close, but, the farmer is not sure as to how much the knob is to be turned, and
would leave the transport lock in an open position, even though he feels he has
closed it.
Secondly, the direction of the oil pressure is required to be perpendicular to the
face of the pilot face. Since the pilot area is less; this creates a large counter
pressure, which makes it difficult for the farmer to turn the knob. Hence, he
has to apply great force to turn the knob against the pressure of the oil.
Thirdly, there were instance of the oil leaking from the transport in closed
condition, as, it is difficult to maintain a condition of concentricity between the
bore of the accessory plate and pilot, causing the failure of prime functionality
of transport lock.
Further, in the prior art once the knob is locked, the plunger closes the path of
oil flow from pump to cylinder. Therefore, for further upliftmcnt of lift, knob is
required to be unlocked followed by lifting and again locking.
Therefore, it is required to develop a novel transport lock so as to obviate the
drawbacks associated with the currently available lock.
OBJECTS OF THE INVENTION
The primary object of the present invention is to provide novel transport lock
for tractor which overcomes disadvantage(s) associated with the prior art.
-4-
Another object of the present invention is to provide novel transport lock for
tractor which is simple and efficient.
Further object of the present invention 1s to provide novel transport lock for
tractor which is reliable.
Yet another object of the present invention is to provide novel transport lock for
tractor which provides ease in the operation.
Further another object of the present invention 1s to provide novel transport
lock for tractor which avoids leakage.
SUMMARY OF THE INVENTION
This invention provides Novel transport lock for tractor comprising of a knob at
one end and a plunger selector valve at other end with a ball arrangement
therebetween, wherein the knob and valve can be positioned inward/ outward.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Further objects and advantages of this invention will be more apparent from
the ensuing description when read in conjunction with the accompanying
drawings and wherein:
Fig. la and 1 b shows: Conventional transport lock for tractor.
Fig. 2 shows: Novel transport lock according to first embodiment of
present invention.
Fig. 3 shows:
Fig. 4a shows:
Fig. 4b shows:
Fig. Sa shows:
Fig. Sb shows:
Fig. 6a shows:
Fig. 6 b shows:
Fig. 7 a shows:
Fig. 7b shows:
-5-
Spring and ball arrangement and lever for first embodiment
of present invention.
second embodiment of novel transport lock assembly
mounted on hydraulic lift assembly.
second embodiment of novel transport lock according to
present invention.
second embodiment of novel transport lock m normal lift
mode.
circuit diagram corresponding to normal lift mode.
second embodiment of novel transport lock in transport lock
mode.
circuit diagram corresponding to transport lock mode.
second embodiment of novel transport lock in external
circuit mode.
circuit diagram corresponding to transport lock in external
mode.
DETAIL DESCRIPTION OF THE INVENTION WITH R~Ji'ERENCE TO _THE
ACCOMPANYING DRAWINGS:-
The instant invention is directed to novel transport lock for tractor.
Reference may be made to fig. 2 indicating the following: Lever shaft lift oil flow
direction control (1), Pin spring dowel (2), Distributor transport lock (3), circlip
(4), Shaft lift oil flow direction control transport lock (5) and seal 0 ring
accessory cover plate (6).
By keeping the lever in a vertical position, the transport lock position 1s
maintained and by turning the lever clockwise by goa, open position is
..
-6-
maintained, thereby removing the uncertainty of the farmer of how much the
knob is to be turned. Further, a spring and ball arrangement (fig. 3) is provided
indicating the following:- spring and ball arrangemvnt for locking (1.1\) and lever
for circuit on/off (lB). P
It is provided to create a Positive locking position in both the cases, when the
" lever is either in the transport position (lever vertical) or the open position (lever
horizontal), the ball sits inside a hole provided in the lever, which is
compressed by the spring, keeping the lever in locked, tight position. So, the
operator can clearly feel whether the circuit is engaged or disengaged.
By keeping the spool horizontal, the area on which the pressure of the oil is
acting is increased causing the reduction of pressure which the oil is exerting
on the lever, thereby providing ease of engagement and disengagement.
Thus, the transport lock of the present invention overcomes all the problems
associated with the known art and provides ease of operation.
Advantageous Features:-
Operator can determine the exact locking position of the lever, hence,
removing the ambiguity of the known design
Difficulty /Fatigue of turning the knob 5 or 6 times is not involved, as a
simply 90° rotation is required.
Ease in the rotation of the lever.
No chances of Leakage as finish are achieved by honing or lapping
machine.
The above constitutes one embodiment of present invention. i\nother
embodiment of the present invention is disused herein below:-
Reference may be made to fig. 4a, wherein transport lock assembly (T) of the
present invention is mounted with hydraulic lift assembly (H). Again referring
to fig. 4b indicating transport lock (P) mounted on accessory cover plate (A)
constituting the transport lock assembly (T). A lever (L) is provided m
connection with selector valve (2) to actuate the valve inward or outward
according to the requirement.
-7-
Now, reference may be made to fig. Sa indicating normal lift mode of the
transport lock assembly (T).
The transport lock comprising of a knob (1) at one end and plunger selector
valve (2) at other end. The knob (1) is connected to spool (3) thl'Gugh an
actuating member for spool (4). Further, the lock comprising of a ball (5)
resting on a seat provided next to the spool. Said ball is provided in connection
with a resilient material such as spring (6) by means of connecting member (7).
The spring also rests on a seat. The mounting of the transport lock i.e. the
accessory cover plate is provided with an inlet (I) for flow of oil from the pump.
So that, the oil can flow into cylinder through an outlet (0).
The transport lock of the present invention can be operated m three modes
given hereinbelow:-
1. Normal lift mode.
2. Transport lock mode.
3. External circuit mode
Normal lift mode (fig. Sa and Sb).
In normal mode, the flow of oil is allowed from pump to cylinder and vice versa
by keeping the knob inwards and plunger selector valve outwards. When the
knob transport lock is inward, it keeps ball in lift condition allowing oil to enter
cylinder and also return back from cylinder.
Thus, in this mode, ball does not come in path of oil flow. So that, oil can flow
to cylinder or from cylinder to pump.
-8-
Transport lock mode (fig. 6a and 6b)
In the transport lock mode, the knob transport lock is outwards and plunger
selector valve is also outwards. This arrangement allows oil from pump to lift
the ball. So that, oil can enters into the cylinder. However, the ball again sits
on the ball seat thus acting as a non-return valve. So that, oil from cylinder
can't return back and is trapped in the cylinder.
Thus, hydraulic oil from pump flows towards cylinder with the ball in its path.
Oil pushes the ball against the spring for flow into the cylinder, which is
required for uplifting the lift with the help of the transport lock.
External Circuit Mode (fig. 7a and 7b)
In external circuit mode, knob transport lock is in outward position and
plunger selector valve is in inward position thus not allowing ball to lift with oil
pressure from pump. Hence, oil at high pressure flows into the external circuit
having no other path for flow.
In this mode, the valve is set inward by lever. So that, it can rest on inlet of the
cylinder thereby closing the path of oil to cylinder. Hence, the oil has to flow
towards outlet (01) of the lock to operate the trolley.
The lock is made of material such as steel without restricting scope of the
invention to the same.
Advantageous Features:-
1. Transport locking.
2. Lifting from Transport lock on position without unlocking (overload
protection).
3. Lowering lifting of lift rate control.
4. Shut-off knob for trolley operation.
5. Transport locking with three turn of knob.
-.
-9-
6. Less operating effort (spool movement is not against oil pressure).
7. Accurate engagement/ disengagement.
Transport Lock is generally used for the following applications:
External hydraulic application in FT Tractor. In this, it 1s needed to
operate tipping trailer, whereby oil is directed from the internal circuit to
the external circuit.
To maintain height of implement when the tractor is carrying implement
from the farmers home/garage to the field and vice versa (may be
subjected to sealing system of cylinder).
It is to be noted that the present invention is susceptible to modifications,
adaptations and changes by those skilled in the art. Such variant embodiments
employing the concepts and features of this invention are intended to be within
the scope of the present invention, which is further set forth under the
following claims:-

WE CLAIM:
1. Novel transport lock for tractor comprising of a knob at one end and a
plunger selector valve at other end with a ball arrangement
therebetween, wherein the knob and valve can be positioned
inward/ outward.
2. Novel transportlock as claimed in claim 1, wherein the knob is connected
to a spool through an actuating member for spool.
3. Novel transport lock as claimed in claim 1 or 2, wherein the ball next to
the spool is provided in connection with a resilient material such as
spring by means of a connecting member.
4. Novel transport lock as claimed in any of the preceding claims, wherein
the lock is mounted on a cover plate provided with an inlet for oil flow
from pump to cylinder through an outlet, in which the lock comprising of
an outlet for supply of oil to trolley.
5. Novel transport lock as claimed in any of the preceding claims, wherein
in normal mode, the flow of oil is allowed from pump to cylinder and viceversa
by keeping the knob inwards and plunger selector valve outwards.
6. Novel transport lock as claimed in any of the preceding claims, wherein
in transport lock mode, the knob and plunger selector valve are outwards
thereby allowing flow of oil from pump into cylinder.
-11-
7. Novel transport lock as claimed in any of the preceding claims, wherein
in external circuit mode, knob is outward and plunger selector valve is
inward, thereby allowing flow of oil through outlet of the lock so as to
operate trolley.
8. Novel transport lock as claimed in any of the preceding claims, 1s
associated with the advantageous features such as herein described.
9. Novel transport lock for tractor substantially as herein described with
reference to the accompanying drawings.