Title of Invention

A HYDRAULIC DISTRIBUTOR SYSTEM FOR TRACTORS AND AGRICULTURAL MACHINES

Abstract

A distributor for tractor & agricultural machine hydraulics system comprising of cast iron housing having inlet port for oil, outlet port connecting to lift cylinder, a port to connect external hydraulics(single acting auxiliary application & discharge/drain ports. It also have main spoon sleeve to control neutral & lift state. Lowering valve assay to control drop state, unloading valve to drain pump flow to tank in neutral state, damping valve assembly to modulate flow at start & end of list stroke, pump & cylinder safety valves, mode selector valve, drop rate adjuster, check valve assembly & sensitivity knob.

Full Text

BACKGROUND OF THE INVENTION: The present invention relates to a distributor for hydraulic system which is controlled with respect to lift position & external force for tractors & agricultural machines. This distributor is specifically used to control the movement of tractors three point hitch on which soil engaging & non soil engaging implements are connected. Various types of hydraulic system & its distributor for tractor & agricultural machine lift system are known. Typically distributors of known types comprises of a body with various valve elements like spool which gets operated by servo mechanical linkage via hand operated position or draft lever. The spool movement controls the flow rate of oil to actuator cylinder & discharge from same. The Tractor hydraulic systems is normally open type & have fixed displacement pump for cost effectiveness. To keep the system simple the distributor does not have external port for auxiliary application like single acting tipping trolley cylinder. One need to make separate arrangements for it. The pump & safety valves are also maintained separately. Moreover the tractor operators in various soil conditions where for optimum & effective use one needs different valves sensitivity i.e. valve neutral band. The above type of user friendly provision is not there in know distributors. Similarly flexibility to adjust drop rate is also not usually there. To get precision lift rate the known system achieve it thro very complicated & expensive valve system. To take care of above issues the known solutions involve substantial increase in volume of the distributor or complicate the system with additional separate valves & difficult to operate & control. Reference cited: U.S.Patents Documents 1.4,176,685 12/1979 Hoofer et al. 137/596.13 2.4,246,832 1/1981 Hoofer etal. 91/461X 3.6,105,613 8/2000 Cornia 137/596.13 SUMMARY OF THE INVENTION: The aim of the present invention is to overcome the disadvantage mentioned above by means of an improved distributor which is simple, compact, easy to manufacture & assemble. With the present invention it is possible to obtain controlled position operation with more than 250 different positions (steps) of lift arms Another advantage of the invention is that the distributors have a mode selector valve & external port for operating auxiliary single acting cylinder. It also consists of pump & cylinder safety valve to improve reliability as generally auxiliary cylinder does not have safety valves. It also have manually operated external sensitivity adjustment knob to suite various soil implements & operating conditions. The distributor also have drop adjuster & controlled lift rate at start & end of stroke to ensure smooth jerk free operation. A further advantage of the invention is that all critical valves are in cartridge form for ease of assembly & maintenance. The distributor gets mounted externally for further ease of assembly & usability. In order to achieve the objectives mentioned above, the invention disclose a new & improved distribution for tractor & agricultural machine hydraulics system comprising of a cast iron housing having four ports ie. inlet port for oil, outlet port for connecting to lift cylinder, a port for external hydraulic (Single acting Auxiliary application) & discharge/drain ports .It also have main spool sleeve to control Neutral & lift state, lowering valve assy to control drop state, unloading valve assy to drain pump flow to tank in neutral state, damping valve assy to modulate flow at start & end of lift stroke, pump & cylinder safety valves resp, mode selector valve, drop rate adjuster, check valve assy & sensitivity knob. BRIEF DESCRIPTION ON THE DRAWING: Further characteristics & advantages will became clear from the following description of a preferred embodiment, with reference to the appended drawings, which are given purely by way of non-limiting example & in which Fig 1&2 are front & rear isometric views of a distributor according to the present invention. Figure 3 to 7 are diagrammatic sectional views though various valve elements of the present invention. DETAILED DESCRIPTION OF THE INVENTION Distributor Assy 1.ref. fig. 1 &2 :Consists of a cast iron housing.2(Fig 3),have four ports ie. a) Inlet port/duct.3 from which pump oil flow enters into it,b)Outlet port 4 from which oil enters single actuating hyd. Cylinder 5,which typically lifts & lowers the three pt. linkage of tractor,( c ) port 6 for connecting to external single acting auxiliary cylinders, like for Tipping trailer trolley, incase port 6 is used & one wants to restrict flow inside tractor cylinder (port 4) then mode selector valve 7 can be activated namely by external control's' eg.knob. Lock plate arrangement,9 restrict accidental use of mode selector valve.(d) drain port 10 from where pump flow goes to tank in neutral condition via unloading valve. Inlet port. 3 connects to chamber 11 & 12 (Fig 4) of unloading valve 13 & damping valve 14 respectively. It further goes & terminates in to the housing bore of main spool sleeve 15 (Fig 3) & into chamber 16 through inlet holes '17' in the sleeve '15a'.Depending on the position of spool '15b' oil moves out from holes '18' of the sleeve & gets diverted to chamber'19' (Fig 4) ie spring side of the damping valve '14' & to the check valve assy'20' (Fig 6) through machined hole in the cartridge type check valve seat'21 In the lift condition (depending on the spool position) the oil opens the check valve ball against spring force & moves further to outlet '4' as described above.Through a drilled hole between check valve & mode selector valve oil communicates with drop rate adjuster valve assy'27' (Fig 7), & lowering valve assy'22' through holes '23' in its sleeve 22a.In the down condition its spool '22b' vents the holes 23 (Fig 3) to tank(sump) via drilled passage '24' in spool. To safeguard against excess pressure there are two safety valve ie. pump safety valve assy'25' (Fig 5), ,its upstream is connected to port 3, & cylinder safety valve assy'26' connected downstream of check valve 20. The lowering valve sleeve'22a' (Fig 3), is stepped. The bigger diameter is toward the spring & butts against sensitivity knob screw'28'.The valve sensitivity (dead band/Neutral band)can be varied by screw'28' ie if the screw is rotated CCW ie.(outwards) then sleeve '22a',under system pressure, acting on differential area of to stepped sleeve, move out wards with respect to spool thereby varing the dead band. This adds versitality for using the valve system for different implements & soil conditions. Spoor22b' moves in tandem with main spool 15b thro adjustable valve lifter'29'. In the neutral condition spool 15b uncovers port 30 in sleeve 15 a to tank. Port 30 is connected to the chamber'31' (Fig 4) i.e spring side of the unloading valvel13.The chamber 11 is connected to chamber 31 by a small orifice '32' in the unloading valve. In neutral condition due to uncovering of port 30 the unloading valve lifts up against its spring force because of differential pressure & there by unload the total inflow from pump to tank(sump) thro chamber 10. In lift condition the spool 15 b slide IN thereby port '30' gets closed & hence unloading valve gets closed by sitting on its seat against spring force. Oil moves from sleeve 15a inlet holes 17 to variable dia holes '18' to check valve & than moves the cylinder. In down condition the spool 14 b slides outwards here port 30 remains open & hence pump flow goes to tank as in neutral condition. Spool 22b also moves out due to its spring force as its front side is in contact with spool 15 b thro valve lifter.29This opens port 23 to tank & thereby cylinder oil moves to tank & brings the lift down. When spool 15b moves in from Neutral to lift condition holes 18 gets slowly uncovered. Location of the holes 18 are controlled & optimized to get desired pressure drop i.e. during transient from neutral to lift one gets less opening of the holes. An internal gallery communicates volume at 18 to chamber 19 of damping valve. So in Neutral to lift transient case pressure drop at chamber 19 will be more than chamber 12.lf this pressure drop is more than damping valve spring force then the damping valve open & chamber 12 gets connected to tank port 33.Hence excess flow gets diverted to tank & less flow goes to hydraulics cylinder. There by ensuring slow start & end of lift cycle ie smooth jerk free movement of lift. According to one of the preferred embodiment, the present invention describes a distributor for a tractor operable with hydraulic cylinders and pistons connected through valves to a pump supplying oil, a tank holding the hydraulic/transmission oil that feeds the pump and a valve operable by the operator, directly or through mechanical servo linkages, to actuate the hydraulic cylinders. The said distributor as per the invention is an assembly of valves which actuated by a spool valve creating chambers around the sleeves and regulating applying both forward and backward flow / pressure to the cylinder/piston comprising of a valve body forming a chamber within holding the oil going through the valve with plurality of openings/ports from which movement occurs from one port to another controlled by the valve. Further the said distributor as per the invention shall comprises of a housing (2) forming a bore chambers within; an inlet port (3) on the housing for pressurized oil flow from the pump; an inlet port (4) on the housing for connecting to lift cylinders; a port (6) on the housing for connecting to external single acting auxiliary cylinders ; drain ports (10,24,33) on the housing for connecting to the tank; a main spool (15 b) and sleeve (15 a) within the bore (15) of the housing. In another aspect of the invention, the said distributor further shall includes a first set of holes (17) in sleeve (15 a) connected to a chamber (16); a second set of holes (18) on sleeve (15 a) connected to a chamber (19) and also connected to check valve (21) which is operable by spool (15 b). A port (30) is provided on sleeve (15a) which operable by spool (15b) is connected to a chamber (31) and an unloading valve (13) having the chamber (31) is provided on its spring side and further a chamber (11) on the other side is connected to tank through chamber (10). According to the invention, the said distributor is characterized as wherein the port (30) and the unloading valve (13) alongwith spool (15b) arrangement is such that when valve is in neutral position, the spool (15b) opens port (30), allowing full flow of oil from pump to tank. The said chamber (31) and chamber (11) is connected through an orifice (32) and a damping valve (14) having the chamber (19) is provided on its spring side, and further a check valve (20) on the other side leading to the outlet port (4). According to the invention, the said distributor is characterized as wherein spool (14) of damping valve alongwith the spool (15b) is operable on the port (19), wherein port (19) and damping valve (14) alongwith spool (15b) arrangement is such that when valve is in lift position, spool (15b) opens holes (17) and holes (18) selectively to allow controlled flow from pump to cylinder. According to the invention, the said distributor also further includes a lowering valve (22a) having holes (23) opening to tank via passage (24) and its spool (22 b) is coupled with the spool (15 b) operable on port (30). The said distributor is further characterized as wherein the port (30), alongwith damping valve (14) and lowering valve (22) and also spools 15b & 14b arrangement is such that when valve is in down position, the spool 15b opens the port 30 allowing flow from pump to tank and further spool 15b moves spool 22b to open port 23 thereby allowing flow from cylinder to tank. Further the said distributor as per the invention includes a mode selector valve (7) placed after the check valve (20) and is adapted to connect to port (6). The said port (6) is further adapted to connect to external single acting auxiliary cylinders with a locking means. Further the said distributor as per the invention includes a drop rate adjuster valve (27) coupled to the lowering valve (22) mode selector valve (7) and the check valve (20), a pump safety valve (25) with its upstream end connected to the port (3), cylinder safety valve (26) with its upstream end connected to check valve (20), and a sensitivity knob (28) manually operable to adjust the valve sensitivity. Keeping principal of the invention same the shape & details of construction may vary widely with respect to those described & illustrated, without thereby departing from the scope of the present invention. WE CLAIM: 1. A distributor for a tractor operable with hydraulic cylinders and pistons connected through valves to a pump supplying oil, a tank holding the hydraulic/transmission oil that feeds the pump and a valve operable by the operator, directly or through mechanical servo linkages, to actuate the hydraulic cylinders, the said distributor is an assembly of valves which actuated by a spool valve creating chambers around the sleeves and regulating applying both forward and backward flow pressure to the cylinder/piston comprising of a valve body forming a chamber within holding the oil going through the valve with plurality of openings/ports from which movement occurs from one port to another controlled by the valve. The said distributor comprising of: a) a housing (2) forming a bore chambers within; b) an inlet port (3) on the housing for pressurized oil flow from the pump; c) an inlet port (4) on the housing for connecting to lift cylinders; d) a port (6) on the housing for connecting to external single acting auxiliary cylinders; e) drain ports (10,24,33) on the housing for connecting to the tank; f) a main spool (15 b)and sleeve(15a) within the bore(15)of the housing; g) a first set of holes (17) in sleeve (15 a) connecting to a chamber (16); h) a second set of holes (18) on sleeve (15 a) connecting to a chamber (19) and connecting to check valve (21) operable by spool (15 b); i) a port (30) on sleeve (15a) operable by spool (15b) and connecting to a chamber (31); j) an unloading valve (13) having the chamber (31) on its spring side and a chamber (11) on the other side connecting to tank through chamber (10), wherein the port (30) and the unloading valve (13) along with spool (15b) arrangement is such that when valve is in neutral position, the spool (15b) opens port (30), allowing full flow of oil from pump to tank; k) said chamber (31) and chamber (11) connected through an orifice (32); I) a damping valve (14) having the chamber (19) on its spring side, and a check valve (20) on the other side leading to the outlet port (4) and further its spool (14b) alongwith the spool (15b) operable on the port (30), wherein port (30) and damping valve (14) alongwith spool (15b) arrangement is such that when valve is in lift position, the spool (15b) closes port (30) and spool (15b) opens holes (17) and holes (18) selectively to allow controlled flow from pump to cylinder; m) a lowering valve (22a) having holes (23) opening to tank via passage (24) and its spool (22 b) coupled with the spool (15 b) operable on port (30), wherein the port (30), along with damping valve (14) and lowering valve (22) and also spools 15b & 14b arrangement is such that when valve is in down position, the spool 15b opens the port 30 allowing flow from pump to tank and further spool 15b moves spool 22b to open port 23 thereby allowing flow from cylinder to tank; n) a mode selector valve (7) placed after the check valve (20) and adapted to connect to port (6); o) said port (6) further adapted to connect to external single acting auxiliary cylinders with a locking means; p) a rate adjuster valve (27) coupled to the lowering valve (22) mode selector valve (7) and the check valve (20); q) a pump safety valve (25) with its upstream end connected to the port (3); r) cylinder safety valve (26) with its upstream end connected to check valve (20); and s) a sensitivity knob (28) manually operable to adjust the valve sensitivity 2. A distributor for a tractor as claimed in claim 1, wherein the sleeve (22a) is stepped. 3. A distributor for a tractor as claimed in claim 1, wherein the sleeve (15 a) is stepped. 4. A distributor for a tractor as claimed in claim 1, wherein the diameter of sleeve (22 a) is increasing towards the spring. 5. A distributor for a tractor as claimed in claim 1, wherein the sleeve (15 a) is abutting against the sensitivity knob (28). 6. A distributor for a tractor as claimed in claim 1, wherein the spool (22 b) is movable in tandem with main spool (15 b) with an adjustable valve lifter (29). 7. A distributor for a tractor as claimed in claim 1, wherein check assembly (20) further includes machined holes in the cartridge type check valve seat (21). 8. A distributor for a tractor as claimed in claim 1, wherein the locking means has a lock plate arrangement (9) to prevent accidental use of mode selector (7). Dated on this the 20th day of February, 2008. For TAPE Motors and Tractors Limited, By its Attorney,

Documents:

426-CHE-2008 COMPARISON CHAT 19-11-2013.pdf

426-CHE-2008 CORRESPONDENCE OTHERS 19-11-2013.pdf

426-CHE-2008 EXAMINATION REPORT REPLY RECIEVED 28-08-2014.pdf

426-CHE-2008 AMENDED CLAIMS 28-08-2014.pdf

426-CHE-2008 AMENDED PAGES OF SPECIFICA TION 28-08-2014.pdf

426-che-2008-abstract.pdf

426-che-2008-claims.pdf

426-che-2008-correspondnece-others.pdf

426-che-2008-description(complete).pdf

426-che-2008-drawings.pdf

426-che-2008-form 1.pdf

426-che-2008-form 26.pdf

426-che-2008-form 3.pdf

426-che-2008-form 5.pdf