Crane Spares

Product Details:

Product Details:

Product Details:

Introduction
Lawa Thruster brake is a device to retard the speed of moving machinery and to stop it accurately to the desired position. The braking force is applied to the brake shoes by a pre stressed compression spring. The shoes press on the rotating brake drum retarding its speed, and finally stopping it. The releasing of the brake and compressing of the spring is done by thruster. Other release devices like pneumatic cylinder or manual release arrangements can be offered on request.

Construction And Operation
Thruster brake has a pair of cast iron shoes which are lined up with friction pads. The shoes are hinged on main arm and side arm of the brake. Each of them have a hinge pin fitted in the base. They are connected to each other on top by a tie rod, which is hinged in the main arm and locked to the swivel block in the side arm, by a lock nut. 

A crank lever is hinged on the main arm, and the other end is fixed to the top clevis of the thruster by a hinge pin. A brake spring, is fixed on the main arm and is pre-loaded by a locknut on the lever, pre-tension in this spring decides the breaking torque. The thruster is fitted on the base by a hinge pin. When the thruster is not energized, the brake shoes are pressed on the brake drum fitted on the drive motor shaft and hold it under the effect of braking force provided by the spring. In such condition, the brake is applied, and the drum cannot rotate. When the thruster motor is energized, the thrust provided by the thruster lifts up the crank lever which move the arms and the shoes away from the brake drum, there by releasing the braking force. The spring is compressed and braking energy is stored for the next cycle.

FOUNDATION
To install the brake, the foundation must be made ready with tapped holes of proper size as per the dimensions mentioned in the dimension table. Care must be taken to ensure the center line of the brake coincides with the centerline of the brake drum and also the level of mounting pads “h” is matching with the center height of the brake drum.

INSTALLING BRAKE IN POSITION
To insert the brake in position the brake shoes are to be taken apart to clear the drum diameter. To do this, slacken the setting bolts and the tie-rod nuts in the side arm pull it slightly. This will increase the distance between the brake shoes and the brake can now be inserted on the foundation bolts and the shoes can be positioned on the brake drum. Re-tighten the setting bolt and the tie-rod nuts. Tighten the mounting bolts.

INSTALLING THRUSTER ON BRAKE
The thruster to be filled with sufficient quantity of oil as mentioned in the Thruster Table. To mount the thruster on the brake, remove one side split pins on the thruster hinge pins of the brake and the lever. Remove both pins and re-insert them after positioning the thruster on the pin holes in the base and lever of the brake, replace both split pins, check that the thruster movement is unobstructed when the crank lever is pulled manually and the thrust rod of the thruster and connect 3-phacse, 415 Volts power supply cables to the three terminals on the terminal plate inside the terminal box. Terminate the earthing lead on the earth terminal provided on the thruster or brake. Replace the terminal box cover on the terminal box. The thruster is ready for operation.

ALIGNING AND SETTING OF BRAKE
Next, align the brake shoes with the diameter and surface of the brake drum and adjust the nuts on the tie- rod such that both shoes grip the brake drum equally. Energize the power cables. 

Lawatherm make spring operated cable reeling drums are powered with springs and has an automatic rewind feature which provides an extremely simple way of supplying power to machines such as cranes and hoists. These spring cable reeling drums are used for both AC and DC applications. These reels recovers and store the cable in multiple layers on the drum. Standard reels are supplied for the cable fed in the clockwise direction, when viewed from the slipring side. The same can be provided for anticlockwise feed of cable also. These reels are extremely simple to mount, and can be mounted on the structure with the help of a supporting flange – If no suitable structure is available, then Vibrator Motor (Unbalanced) can be connected to the flange and this can be fixed to the floor or tray etc.
The springs used in these reels are manufactured from the highest quality materials and are of clock spring type. A wide range of characteristics can be obtained by assembling these springs singly or in series or in parallel.

Product Details:

Product Details:

Introduction
Lawatherm Lever ( and weight operated ) type Limit Switch LLS / CWLS operates the control change-over Contacts of motor of an moving
equipment when a Cam moving with loads actuates the Lever of limit switch. This turns the cams on a square shaft and operates the NO / NC
contact elements.

Operation
Two or more Contact Elements are operated by respective rotating Cams, which are suitably fixed on a square Cam Shaft turned by a lever or
weight. The contacts operate at 14 from central neutral position.

Design
The Sheet Steel body, Lever and Cover of the Limit Switch are finished by powder coating treatment. The Cam Shaft is mounted in the housing
on moulded Nylon bushes ( bearing) and are fixed through the front & rear walls.

Technical Data :
Body material                         Powder coated sheet
Degree of protection            IP- 41
Mounting position                Floor mounting
Cable entries                          Twin. 3/4’ BS conduit
No. of contact                         2 / 3 /or 4
Wire connection                   Silver-cadmimum
Rated voltage                         500 V ac
Thermal test current             10 A  

Operating Executions :
The operating mechanism can be offered in two executions:

1. Roller Operating A Lever :
These Limit Switches are used for E.O.T. Cranes, Wagon Shunting devices, Elevators, Travel mechanism or such linearly moving mechanisms to prevent over-travel. The position of operating lever is in up / down, and can be changed in steps of 90 at site.

2. Lever Actuated By A Dead Weight :
These Limit Switches are used to prevent over hoist motion with weight. Counter weight is provided in this case. The same is lifted with wire rope to prevent over hoist position.

FLEXIBLE GEARED COUPLINGS
The Lawatherm Flexible Geared Couplings are suitable for over coming the following type of misalignments. Parallel Offset: Where axis of connected shafts are parallel but not within the same straight line. Angular: Axes of shafts intersect at the center of coupling. Combined Angular: Offset axes of shafts are neither parallel nor do they intersect. Hubs of Lawatherm make Couplings are machined from EN-9 Steel forgings to close tolerances for accurate alignments and proper balance.

ROTARY GEARED LIMIT SWITCHES (MODEL GRLS)
Introduction
Lawatherm Rotary Geared Limit Switch GRLS is used to trip supply when the moving loads reach the extreme end positions of working zone.

Operation
A two (for more) Contact Elements area operated by respective rotating Cams, suitable adjusted on a Cam Shaft which rotates with fixed speed ratio of the drive motor shaft. The cams can be suitably positioned so that they trip motor supply and stop the motion at the required point of travel.

Application
Rotary Geared limit Switches are suitable for use on reversing drives such as Hoists, Winches, Rolling Mills and various other mechanisms used in Steel Plants such as Coke Oven, Feeding machinery etc.

Lawatherm hoist trolleys provide the connection between the lifting device and the bridge. The trolleys are designed for effortless movement along the bridge.
The stamped body fits most rigid hook or eye lifting device. Festoon clamps anchor the festooning at the start of the runway and bridge. Festoon trolley is used to support flat cable or air hose along the runaway or bridge. The trolleys have four wheels and a pivoting festoon saddle support. They are ideally suited for long runways or with round cable or air hose..

Product Details:

ELECTRICAL SUPPLY
Unless otherwise specified, all thrusters are suitable for operation for 415 Volts,-phase, 50 Hz power supply. Thrusters for other voltages up to 600 VAC, 3-phase can be supplied against specific enquiries.

Connections
Lawatherm Thrusters operated equally well in both directions of rotation. Therefore, the three phase supply lines can be connected the Thrusters in any R-Y-B phase sequence. Provide adequate safety backups.

Oil Requirements
Thrusters are supplied without oil to avoid spillage during transportation. They must be filled with sufficient quantity of oil before installation. For all models of thrusters, it is recommended to use Transformer Oil as specified in BS : 148. Oil capacity requirements are listed in the table below.

Installation Of Thrusters
Lawatherm Thrusters are suitable for vertical mounting only. After filling the thruster with required quantity of oil. Install it by using the clevis and hinge pins provided. Insert the locking spilt pins. Ensure that no excessive transverse forces are acting on the thrust rod. Wipe out the dust, paint or oil deposits from the operating section of the thrust rod pins by dry and clean cloth.

MAINTENANCE
Lawatherm Thrusters is designed for long trouble free service. The motor windings are designed to meet contingencies. The bearings are adequately sized. Routine maintenance schedule includes checking the oil level and topping them if necessary. If oil contamination is detected, drain it out completely and refill with fresh oil. Check and correct the oil leakage if detected.

The Lawatherm Flexible Geared Couplings are suitable for over coming the following type of misalignments. Parallel Offset: Where axis of connected shafts are parallel but not within the same straight line. Angular: Axes of shafts intersect at the center of coupling. Combined Angular: Offset axes of shafts are neither parallel nor do they intersect. Hubs of Lawatherm make Couplings are machined from EN-9 Steel forgings to close tolerances for accurate alignments and proper balance.

Introduction
Lawatherm Master Controllers are used for remote operation of Contactors in equipment such as E.O.T. Cranes & Rolling mills drives. The Controllers are made in dust proof enclosure in IP-41 degree of protection, up to 6 notches either side with maximum 24 contacts as per desired sequence. Spring return arrangement & Dead man’s handle arrangement are also available.

General
Master Controllers are of cam type where in contacts are actuated by individual cams mounted on operated shaft. The Shaft are cut accordingly to the type of sequence required by the customers. For this a blank sequence diagram can be provided by us to be filled in by the customers.

Construction
Master Controller is housed in enclosure and provided with an easily removable cover with ample area for maintenance. The cam shaft is mounted on bearing bushes on walls of housing. The cams are made of delrin material and fixed on square.

Technical Data:
Body Material – Sheet Steel ( POWDER COATED)
Protection Degree – IP-41
Confirming to IS – 13947 (Part-1) 1993
Mounting Position – Horizontal / Vertical
Contact Material – Silver Cadmium
Rated Voltage Insulation – 500 V. A.C
Thermal Test Current -10 Amps.
Cable entries – 2×20Ø 2×2Ø standard conduit
Frequency of operation – 1000 switching per hour
No. of contacts – 24 maximum
No. of steps – 6-0-6 maximum
Optional – Spring return / Deadman’s
Handle arrangement