DESC:FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
The Patent Rules, 2003
COMPLETE SPECIFICATION
(See sections 10 & rule 13)
1. TITLE OF THE INVENTION
A RETARDER ASSEMBLY AND ITS METHOD FOR THE MOVEMENT OF DIPPER DOOR
2. APPLICANT (S)
NAME NATIONALITY ADDRESS
BEML LIMITED IN BEML Soudha, No 23/1, 4th Main S.R. Nagar, Bengaluru- 560027, Karnataka, India.
3. PREAMBLE TO THE DESCRIPTION
COMPLETE SPECIFICATION

The following specification particularly describes the invention and the manner in which it is to be performed.

FIELD OF INVENTION:
[001] The present invention relates to the field of machines having a dipper to scoop and unloading of material at a worksite. The present invention in particular relates to a retarder assembly and its method for the movement of dipper door.
DESCRIPTION OF THE RELATED ART:
[002] The discharge of materials from bucket for high-end face shovel excavators like BE700, BE1000, BE1800 happens through Bottom dump mechanism. This mechanism is consisting of hydraulically operated cylinders mounted on door and bucket respectively. Since it is hydraulically operated mechanism, operator closes the bucket during scooping position and opens it during the discharge position with controlled operating parameters.
[003] Reference may be made to the following:
[004] Publication No. WO2022182617 relates a snubber system for retarding a swinging movement of a door with respect to a body of the dipper. The snubber system includes a braking assembly an arm structure and a link structure. The braking assembly is configured to be fixedly mounted to the body. The arm structure is configured to execute rotation about a first axis the rotation of the arm structure being dampened by the braking assembly. The link structure is rotatably coupled to the arm structure to rotate about a second axis and is movable in correspondence with the swinging movement of the door to exert and transfer a force, F, to the arm structure. A direction of the force, F, defines an angle between 80 - 100 degrees with respect to an axis or a plane passing through the first axis and the second axis throughout the swinging movement of the door.
[005] Publication No. CA2735055 relates a retarding mechanism for continuously retarding the swinging movements of a dipper door is disclosed. The retarding mechanism comprises a hydraulic braking assembly mounted to the dipper bucket and operatively connected to the dipper door via at least one braking arm pivotally mounted within the braking assembly and at least one linking member pivotally mounted to the dipper door. The retarding mechanism continuously retards the opening and closing movements of the dipper door by controllably braking or slowing the at least one braking arm using the compressive action of at least one hydraulic piston mounted to the braking assembly.
[006] Patent No. US11066807 relates a mining machine includes a boom, a handle coupled to the boom, a dipper coupled to the handle, and a dipper door pivotally coupled to the dipper. The mining shovel also includes a dipper door trip assembly including a trip motor coupled to the boom, a trip drum coupled to the handle, a linkage assembly coupled to the dipper door, a first actuation element extending directly from the trip motor to the trip drum, and a second actuation element extending directly from the trip drum to the linkage assembly.
[007] Patent No. US4517756 relates a snubber for use with a dipper to retard movement of the dipper door toward and away from an opening formed in the dipper. The snubber includes an elastic member and an actuator link. When the door is at a first angle with respect to the dipper, the elastic member is in tension to retard movement of the door toward the dipper. When the door is at a second angle with respect to the dipper, the elastic member is in bending to retard movement of the door away from the dipper. The snubber is inactive when the door is at an angle between the first and second angles.
[008] Publication No. US2007107269 relates a dipper including a dipper door and an impact actuated jaw having a "C" shape defining a lip and a chin. The jaw is rotatably mounted on the dipper door for rotation between a door-opened position and a door-closed position and positioned so that when the jaw is in the door-opened position, the jaw chin can be impacted by the dipper body when the door pivots to the door-closed position. The dipper also includes a hold open mechanism for releasably holding the door latch in the latch open position when the latch is in the open position, and a locking mechanism for releasably locking the latch when the latch is in the door-closed position. The locking mechanism includes one bar pivotally attached to the door, and another bar pivotally connected to and extending between each of the one bar and the latch.
[009] Publication No. US2002040540 relates a dipper assembly includes a dipper having an open bottom and forward end, and a door pivotally linked to the dipper. The dipper bottom is defined by dipper wall bottom edges. The door has a bottom wall and side walls which extend above the bottom wall to define a volume between the side walls, wherein top edges of the side walls abut bottom edges of the dipper wall bottom edges to close the dipper bottom.
[010] Publication No. US2014165431 relates a dipper assembly for a mining shovel, includes a dipper having a dipper back and an open dipper bottom, and a dipper door pivotally mounted to the dipper, configured to pivot between an open position and a closed position with a swing speed, and to cover the open dipper bottom. The dipper assembly also includes one or more hydraulic door snubbers. The hydraulic door snubbers include a base having one or more connecting plates, one or more mounting plates coupled to the base and configured to receive a link extending from the dipper door, one or more friction plates, and a hydraulic cylinder configured to clamp the mounting plates, the connecting plates, the friction plates and the link together.
[011] Publication No. US2016024746 relates a snubber for a machine. The snubber includes a frame that is mounted on an implement of the machine, a shaft that is operatively coupled to a movable component of the implement and a housing that is coupled to the shaft and rotatably received within the frame. The housing defines a cavity that is configured to store a fluid therein in a sealed manner. The snubber also includes at least one brake disc disposed within the housing and configured to rotate with the shaft and at least one brake pad disposed within the housing and configured to frictionally engage with the at least one brake disc to oppose rotational movement of the housing relative to the frame. The fluid is configured to at least partly remove heat generated due to the frictional engagement between the at least one brake disc and the at least one brake pad.
[012] Publication No. EP2998609 relates a hydraulically operated pivotal joint for dampening a swing motion of a swing damping device, the hydraulically operated pivotal joint comprising a non-pivoting pin, a first inner channel arrangement comprising a first pressure inlet for providing an inlet for a pressure medium, a first braking arrangement arranged to create a braking force for dampening the swing motion, wherein the braking force is provided by the first braking arrangement by means of pressure provided by the pressure medium conducted to the first braking arrangement via the first inner channel arrangement. The first inner channel arrangement comprises a first pressure outlet, where to the pressure medium is conducted from the first pressure inlet through the non-pivoting pin and through the first braking arrangement to enable conducting of the pressure medium for a second hydraulically operated moving apparatus of the swing damping device.
[013] Publication No. US2013192101 relates a dipper assembly includes a dipper, a dipper door, a closure mechanism, a trip assembly, and a camshaft support assembly. The dipper door is pivotally mounted to the dipper for movement between an open position and a closed position in which the dipper door covers the dipper bottom. The closure mechanism is configured to retain the dipper door in the closed position. The trip assembly is configured to release the dipper door for movement to the open position, and includes a trip arm coupled to a camshaft and also coupled to a trip rope. The camshaft support assembly is configured to receive the camshaft, and includes a bearing block receiving a rotatable bearing member, and a sealing mechanism.
[014] Publication No. US2014205415 relates an actuator system for a machine includes a linear hydraulic actuator connected to a dipper of the machine, and a hydraulic system fluidly connected to the actuator and configured to selectively direct fluid to the actuator. A component of the hydraulic system is mounted on the dipper. The system also includes an overcenter link coupled to a door of the dipper and biased to maintain the door in a closed position. A piston assembly of the actuator is configured to move the overcenter link in a first direction, via contact between the piston assembly and the overcenter link, thereby transitioning the door from the closed position to an open position.
[015] Publication No. US2014205414 relates a hydraulic system for a power shovel. The hydraulic system may have a cylinder operatively connectable to a dipper door of the power shovel, a reservoir located at and fluidly connected to the cylinder, and an accumulator located at and fluidly connected to the cylinder in parallel with the reservoir. The hydraulic system may further have a control valve disposed between the cylinder, the reservoir, and the accumulator. The control valve may be movable to selectively direct fluid from the cylinder into the accumulator and fluid from the reservoir into the cylinder.
[016] Publication No. US2014205412 relates a hydraulic system for a power shovel. The hydraulic system may have a tank, a pump configured to draw fluid from the tank and pressurize the fluid, a crowd cylinder extendable and retractable to adjust a length of a dipper handle, and a valve in fluid communication with the tank, the pump, and the crowd cylinder. The valve may be movable to fill chambers of the crowd cylinder with fluid pressurized by the pump and to drain the chambers of the crowd cylinder to cause extension and retraction of the crowd cylinder. The hydraulic system may also have a dipper actuator located at an end of the crowd cylinder, and a passage extending through the crowd cylinder to communicate with the dipper actuator.
[017] Publication No. US2014202048 relates an actuator system for a machine includes a hydraulic actuator connected to a dipper of the machine, and a hydraulic system fluidly connected to the actuator and configured to selectively direct fluid to the actuator. A component of the hydraulic system is mounted on the dipper. The system also includes an overcenter link coupled to a door of the dipper and biased to maintain the door in a closed position. The actuator is operable to move the overcenter link in a first direction, thereby transitioning the door from the closed position to an open position.
[018] As BRS21 Rope shovel is powered by electric current, and no hydraulic pack available, mechanical based retarder assembly and its method for the movement of dipper door is invented.
[019] In order to overcome above listed prior art, the present invention aims to provide a retarder assembly and its method for the movement of dipper door. The mechanism doesn’t need any external energy source for controlled movement of door, except for operating controls.
OBJECTS OF THE INVENTION:
[020] The principal object of the present invention is to provide a retarder assembly and its method for the movement of dipper door.
[021] Another object of the present invention is to provide a retarder assembly which prevents the structural failure of the door.
[022] Yet another object of the present invention is to provide a retarder assembly which ensures the controlled movement of door by retarding to specified requirement.
[023] Still another object of the present invention is to provide a retarder assembly which prevents the structural failure of door and provides smooth opening and closing of the door by retarding the dipper door movement.
[024] Yet another object of the present invention is to provide a retarder assembly which ensures the smooth opening and closing of the door.
[025] Still another object of the present invention is to provide a retarder assembly does not use latch lever bar and insert for the retardation of door.
SUMMARY OF THE INVENTION:
[026] The present invention relates to the retarder assembly and its method for the movement of dipper door. This is a cost effective, easy to maintain retarder assembly which provides long service life and high durability. This invention is used for rope shovel with different dipper capacities and different operating weights. This invention also shall be used in material handling equipment’s to discharge the material.
[027] This invention prevents the structural failure of door and provides smooth opening and closing of the door by retarding the dipper door movement.
BREIF DESCRIPTION OF THE INVENTION
[028] It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered for limiting of its scope, for the invention may admit to other equally effective embodiments.
[029] Figure 1 (a,b) illustrates an electric rope shovel, large surface mining electric equipment, used for scooping the overburden and dump into the dumper.
[030] Figure 2 shows the latch bar removed by operator.
[031] Figure 3 shows retarder assembly and its linkage mechanism of BRS21 rope shovel.
[032] Figure 4 shows isometric view of retarder assembly and its mechanism.
DETAILED DESCRIPTION OF THE INVENTION:
[033] The present invention provides a retarder assembly and its method for the movement of dipper door. This is a cost effective, easy to maintain retarder assembly which provides long service life and high durability. This invention is used for rope shovel with different dipper capacities and different operating weights. This invention also shall be used in material handling equipment’s to discharge the material.
[034] Figure 1 (a,b) illustrates an Electric Rope shovel, large surface mining electric equipment, used for scooping the overburden and dump into the dumper The system comprises Dipper handle (1), Dipper door (2), housing (3), link1 (4), link 2 (5), retarded pad (6), compression spring (7) pins, rod, bar, nut, cotter pin and washer. The electric rope shovel consists of three major mechanisms which include lower frame (8), upper frame (9) and work attachment (10). Lower frame provides base to the equipment and consists of propel drive and undercarriage system. The upper rotating structure mounts on lower frame through a pin joint, enables upper structure to rotate about lower frame, and provides mounting to electrical aggregates such as swing machinery, hoist machinery and work attachment. Work attachment consist of boom, yoke block dipper handle assembly and electrical drive machinery used for scooping and dumping the mined material into the dumper. The primary motions of electrical rope shovel include propel forward and reverse, swinging of upper structure, extension and retraction of dipper handle structure by using rack and pinion mechanism.
[035] Dipper handle assembly is an assemble of Dipper door, dipper and dipper handle. Dipper door, weighs 5 tonnes, mounts on dipper through pin joint and will be at closing position during scooping, by means of latch bar mechanism as shown fig.2. After scooping operation, dipper handle goes to a specified height and swings towards the dumper. Then, operator will pull the latch bar out through his controls, intern self-weight of over burden pushes the door out . Upon opening the door, overburden material will be discharged through the opening. Since door is mounted through hinge joint, it will have free oscillation due to gravity. Because of its huge self-weight, both sides of dipper door have impact with neighbouring structures, i.e. dipper and dipper handle, results in structural failure of the dipper door.
[036] This invention prevents the structural failure of door and provides smooth opening and closing of the door by retarding the dipper door movement.
[037] The retarder assembly and its linkage mechanism of BRS21 rope shovel layout is shown in fig.3. This planar mechanism consists of a base structure welded to the dipper handle. 08 nos. of retarder plates mounted on base structure through Pin joint. One pair of link 2 welded to the door. Two pairs of link1 mounted on housing structure at two places as shown in Fig 3. Similarly, links are connected by the pin joints at both ends. Retarder assembly is mounted inside the base structure as shown in fig 3. Figure 4 shows isometric view of retarder assembly and its mechanism. This retarder assembly and its mechanism will enable the user to maintain the required clamping force, as and when, during service life, with required retardation and smooth opening and closing of dipper door.
[038] As operator removes the latch bar as shown fig 2, refer fig 1 for door opening position, for unloading the over burden, door will be opened and oscillating about the door hinge point due to gravity.
[039] To keep the angular acceleration of door to a minimum requirement, eight numbers of retarder pads were introduced between retarder plates as shown in fig. 3. Two compression springs were introduced to maintain the required clamping force, between retarder plates for slow movement of dipper door.
[040] This retarder assembly and its mechanism enables the user to maintain the required clamping force, as and when, during service life, with required retardation and smooth opening and closing of dipper door.
[041] This invention has four bar mechanisms where in length of fixed length is 0, and remaining link lengths exists. A spring with required clamping force and reliability is provided. The retarded plate with required frictional surface provides long service life. Multiple retarded plates with frictional surface and links are stacked in series, mechanical spring for Clamping, that results a required braking force for retarding the door.
[042] Periodical checking is done for finding out the wear out on retarder plates and subsequent adjustment of Clamping force or replacement of retarded plates as required.
[043] Numerous modifications and adaptations of the system of the present invention will be apparent to those skilled in the art, and thus it is intended by the appended claims to cover all such modifications and adaptations which fall within the true spirit and scope of this invention.
,CLAIMS:WE CLAIM:
1. A retarder assembly and the movement of dipper door comprises-
a) Work attachment characterized in that dipper handle (1), Dipper door (2), housing (3), link1 (4), link 2 (5), retarded pad (6), compression spring (7) to maintain the required clamping force, between retarder plates for slow movement of dipper door pins, rod, bar, nut, cotter pin and washer.
b) The electric rope shovel characterized in that lower frame (8), upper frame (9) and work attachment wherein lower frame provides base to the equipment and consists of propel drive and undercarriage system, upper rotating structure mounts on lower frame through a pin joint, enabling upper structure to rotate about lower frame, and provides mounting to electrical aggregates.
2. The retarder assembly and the movement of dipper door, as claimed in claim 1, wherein the primary motions of electrical rope shovel include propel forward and reverse, swinging of upper structure, extension and retraction of dipper handle structure by using rack and pinion mechanism.
3. The retarder assembly and the movement of dipper door, as claimed in claim 1, wherein the dipper handle assembly is an assemble of Dipper door, dipper and dipper handle. Dipper door, weighs 5 tonnes, mounts on dipper through pin joint and will be at closing position during scooping, by means of latch bar mechanism.
4. The retarder assembly and the movement of dipper door, as claimed in claim 1, wherein after scooping operation, dipper handle goes to a specified height and swings towards the dumper, operator will pull the latch bar out through his controls, intern self-weight of over burden pushes the door out.
5. The retarder assembly and the movement of dipper door, as claimed in claim 1, wherein upon opening the door, overburden material will be discharged through the opening, since door is mounted through hinge joint, it will have free oscillation due to gravity and because of its huge self-weight, both sides of dipper door have impact with neighbouring structures, i.e., dipper and dipper handle, results in structural failure of the dipper door.
6. The retarder assembly and the movement of dipper door, as claimed in claim 1, wherein retarder assembly and its linkage mechanism of rope shovel consists of a base structure welded to the dipper handle. 08 nos. of retarder plates mounted on base structure through Pin joint. One pair of link2 welded to the door.
7. The retarder assembly and the movement of dipper door, as claimed in claim 1, wherein two pairs of link1 mounted on housing structure at two places, links are connected by the pin joints at both ends and retarder assembly is mounted inside the base structure 3.
8. The retarder assembly and the movement of dipper door, as claimed in claim 1, wherein as operator removes the latch bar for door opening position, for unloading the over burden, door will be opened and oscillating about the door hinge point due to gravity.
9. The retarder assembly and the movement of dipper door, as claimed in claim 1, wherein eight numbers of retarder pads were introduced between retarder plates.