| Components for Railways |
| Railway Components |
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Wear Plates, Side Bearer, Boister Liner, Rail Joints, Window Sheets and Dust Cover in PC, Suspension Bearing, Techno Generator Gear, Nylon Gear for Governor Drive, Nylon Sheets,Insulating Liners, Pedstal Liner I Adopter, Centre Pivot Liners, Centre Bowl Liners, Centre Pivot, Rollers & Bushings for several applications in Wagon, Signal, Track Electric & Diesel Locos, Distance rings, Pulleys for Cranes, Piston for Boister friction device etc. |
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Fitment and Installation
We have defined international methods especially for plastics design & installations.
Testing
We regularly get our materials tested from Govt. Test Centres like QMC, ClPET and CPSE, liT |
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Ad·rant. JI
- High compressive strength and excellent creep resistance
- High wear resistance and low coefficient of friction
- Self lubricant making greasing redundant no corrosion problems
- No need to grease
- Better wear resistance
- Good machine ability and easy to assemble
- High mechanical strength
- Electrically insulative
- High impact strength
- No corrosion
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Limitations
Nothing but to follow the defined designing and installation procedure & methods for plastics stridly. (For all depts. of Railways)
Application
Locomotives ride on multi-axle trucks with a centering pin and center bowl area at the middle of each truck. Wear surfaces in the center bowl are required to take downward load and oscillating movement of the locomotive.
Original Production Method
Three-piece manganese steel assembly.
Problem
Three-piece assemblies were heavy and required welding to install, and grinding to remove. They wore quickly, especially when not regularly lubricated.
Custom Casting Solution
Polymer introduced the concept of a one-piece" drop-in" center bowl liner made from Bobkay® GSM nylon. This self-lubricating nylon requires no lubrication, is light weight, resilient, strong, and offers superior wear resistance. The part is cast almost completely to size requiring very little finish machining. |
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DSM's Monocast Cable sheaves are being increasingly used on all kinds of hoisting machines: from huge container cranes to mobile cranes and from offshore cranes to grabs. These Monocast nylon sheaves have considerable advantages over the usual steel sheaves.,
THE MATERIAL: Monocast nylon
For years people in the heavy crane building sector have been looking for better materials for the cable sheave.The usual steel sheaves have several disadvantages:
They shorten the useful life of steel hoisting cables.
They increase the 'dead' weight when scaling up, particularly in mobile cranes.
They suffer from corrosion problems, particularly in offshore applications.
Bobkay Cables Sheaves have put an end to all these drawbacks.
Longer-lasting hoisting cables
In comparative tests recognized, independent research consultants have established conclusively that steel cables last longer in combination with Bobkay Monocast sheaves than they do when used with steel sheaves. Depending on the type of steel cable, the useful life was found to increase by 200 to 600% when a Monocast sheave was used. |
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BENEFITS OF CUSTOM CASTING THIS COMPONENT
- Reduces maintenance cost due to longer part life and elimination of lubrication
- Lighter weight BOBKAY® GSM nylon center bowl liners are safer to install and remove
- Easier installation and removal no welding or grinding needed
BOBKAY® SHEAVES REDUCE WEIGHT AND INCREASE CRANE lOAD CAPACITY
Application
Main load, boom point and boom extension sheaves on mobile hydraulic cranes used for wire rope.
Original Production Method
Iron or steel sheaves that are cast then machined.
Problem
Parts are heavy adding to over-the-road and boom hoisting weight, and reducing lifting capacity. Weight of the metal sheaves also makes installation and service difficult. They are prone to rust, and the metal grooves cause severe wean on the wire rope.
Custom Casting Solution
BOBKAY@ GSM nylon sheaves are cast using the unique LPC Custom Casting process and require only machining off of the bore for a press fit bearing. In addition, because BOBKAY@ GSM is only 1/7 the weight of steel, the cranes achieve greater lifting capacity, over-the-road stability, and are easier to service. BOB KAY sheaves do not corrode, and wire rope life is increased.
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BENEFITS OF CUSTOM CASTING THIS COMPONENT
- Improved lifting capacity and over the road performance due to lighter weight
- Easier to install and service
- Parts do not corrode
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Bobkay wear parts have made a significant contribution to diesel-electric locomotive design as the development time span for modern road haul freight trucks has coincided with the evolvement of Bobkay nylon casting and processing. The availability of Bobkay wear parts as a replacement for metal has reduced maintenance costs by providing longer service life while protecting mating contact surfaces. |
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| BOBKAY Materials |
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Bobkay GSM and Bobkay NSM, the two nylon formulations used for diesel-electric truck applications, are Type-6 cast nylons produced by Polymer's' Monocast process in which liquid monomer is directly polymerized inot nylon in metal molds. Bobkay materials provide the optimum range of performance obtainable in slide and thrust bearings under varying operating conditions. In addition to being characterized by a superior combination of high strength, resilience, toughness, and wear resistance, they are lightweight |
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(about 117 the weight of steel), contain built-in lubrication qualities, and are unaffected by most corrosive surroundings, BOBKAY GSM nylon contains finely divided particles of molybdenum disulphide dispersed through out for added surface lubricity. The mechanical strength of BOBKAY GSM nylon allows it to support higher bearing loads than possible with most other thermoplastics. Its high degree of resiliency permits it to retain its original shape without permanent deformation when deflected by non-uniform or rapidly applied working stresses. At the same time, BOBKAY GSM nylon has the impact strength to resist fracture from repeated shock loads. BOBKAY NSM nylon has strength characteristics comparableto BOBKAY GSM but contains special solid lubricants which further enhance friction and wear properties. It is recommended where maximum bearing efficiency is desired in unlubricated installations.
In addition to locomotive wear parts, BOBKAY cast nylons have proven successful in a variety of heavy duty engineering applications in construction, mining, marine, primary metals and other industries. These applications include boom point sheaves for mobile and offshore cranes, foundry elevator buckets, steel mill overhead crane bearings for electric mining shovels. Typical property data for BOBKAY GSM and NSM cast nylons is shown and a comparison wiht other engineering plastic bearing materials is provided in table 1. The data demonstrates that BOBKAY cast nylons exhibit excellent low friction properties, have superior wear resistance, and maintain consistently high modulus and strength over a wide temperature range. Extensive service experience has corroborated the superior performance indicated for these materials. |
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BOBKAY Centre plate liners |
| BK® NSM |
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The center bearing in the boster of diesel-electric trucks supports the weight of the locomotive body and mates with the body center plate. The center bearing cavity is lined wiht a BOBKAY GSM nylon horizontal centre plate liner and two BOBKAY GSM centre plate halfs rings which press fit into place to form the vertical components. The bearing cavity is filled with oil at assembly. BOB KAY centre plate liners are cast-to-size and centre plate half rings are formed from cast plate. The metal filled phenolic parts previously used for this |
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application have been largely replaced by BOBKAY nylon parts because of their superior performance during periods of temporary loss of lubrication. BOBKAY GSM cast-to-size centre plate bowl liners have been developed as an alternative to the horizontal centre plate liners and vertical half rings in the centre bearing cavity. The centre plate bowl liner reduces parts inventory, permits simple one piece installation and eliminates the possibility of upward movement of separate vertical components during operation. |
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PROPERTIES OF BOBKAY GSM AND BOBKAY NSM NYLON |
Property |
Units |
Test Method ASTM |
BOB KAY GSM Value |
BOB KAY NSM Value |
Mechanical and Physical Properties |
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Tensile Ultimate strength
Tensile Elongation at break
Tensile Modulus
Compressive Strength at 1 % offset
Flexural Strength
Flexural Modulus
Tensile Impact
Hardness, Rockwell
Specific Gravity |
Psi
%
Psi
Psi
Psi
Psi
ft.lbs.in.2
R |
D-638
D-638
D-638
D-695
D-790
D-790
D-785
D-792 |
11,000-14,000
10-60
350,000-450,000
12000
16,000-17,500
400,000
80-130
112-120
1.15-1.17 |
9,400
50
320,000
14,000
350,000
90
108
1.13 |
Thermal Properties |
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Melting Point
Coefficient Linear
Thermal Expansion
Deformation
Under Load
(122oF, 2000 psi) % 0-621 0.5-1.0 .90
Deflection Temperature
264 psi
66 psi
Continuous
Service Temp.
In Air (Max.)
Flammability |
of
in.in./of
Â
%
 of
of
 of |
0-789
0-696
0-621
D-648
D-648
D-635 |
430± 10
5.0xl05
0.5-1.0
200-425
400-425
200-225
Self Exting |
430±10
5.0xl05
.90
200
180-200 |
Chemical Properties |
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Water Absorption
24 hours
Saturation % 0-570 5.5-6.5 5.3
Acids
Weak, 73 of
Strong, 73 of
Unacceptable
Alkalies
Weak, 73 of
Strong, 73 of
Hydrocarbons
Aromatic, 73 of
Aliphatic, 73 of
Inorganic Salt
Solutions
73 of |
%
% |
0-570
0-570 |
0.6-1.2
5.5-6.5
Acceptable
Unacceptable
Acceptable
Acceptable
Acceptable
Acceptable
Acceptable |
1.2
5.3
Acceptable
Unacceptable
Acceptable
Acceptable
Acceptable
Acceptable
Acceptable |
Bearing Properties |
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Coefficient of Friction
Static
Dynamic
Max Recommended
Continuous PV
Unlubricated
@ 200 fpm
Unlubricated
@20fpm
Periodic Lubrication -
Wear Factor
"K" x 1010 |
Psi*fpm
Psi*fpm
Psi*fpm |
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17-.23
16-.25
3,000
3,000
16,000
89 |
12-22
12-22
15,000
30,000
21 |
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Note: Property data shown are typical average values and will vary on Specific production lots and by size and configuration of product. They, therefore, should be used only as a guide to primary selection of a given material. and never for purchase specifications. Further technical information is available for specific application requirements. All values shown are based on bone dry specimens. Where no value IS listed, sufficient details are not available to present a usable figure |
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Table 1 Wear Rate and Coefficient of Friction for BOBKAY® Cast Nylon and other Engineering Plastic Bearing Materials |
Bearing Materials      Coefficient of Friction                  Wear factor       Comparative
Static (1) (2) Kinetic (1) (3)Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â "K" (4)Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Wear Rate |
BOBKAY® NSM Nylon         1 2-.22 .        13-. 16                                21                             1.0
BOBKAY® GSM Nylon .     17-.23 .         16-.25                                  89                             4.2
Laminated Phenolic              . 2 5-.23           33-.61                                113                        SA
Polyurethane (Shore 070) .   38-40.           36-.39                                150                         7.1
Acetal (Injection Molded) .    22-.25 .         37-.38                                188                             8.9
UHMWPE .                           11 -.16 .        11-.13                                 231                            11.0
Polyster (Injection Molded) .  26-.32 .         24-.32                  (Failed at 5000 PV) |
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1. Measured on thrust washer testing machine, unlubricated against 1018 steel (RC 20-24), under normal load of 220N (50 Ibs.) or 1720 kPa (250 psi),
2. Measured by applying gradually increasing torque until the bearing completed a 900 rotation in about one second.
3. Measured @ 0.1 m/min/ (20 fpm).
4. Measured on 12.7 mm (112M) '-D. Journal Bearings unlubricated at 5000 PY (118 fpm and 42.4 psi) or (0.6 mfs and 290 kPa).
K = h/PYTx 10· 10 Where h = radial wear Y = Sliding speed
P = normal pressure T = test duration |
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BUSHINGS FOR BRAKE PUll ROD SYSTEM |
A. Application description
Each carriage has a breaking system. In case of a brake pull rod system, plastic bushings are used to guide the oscillatory movement of the break pads (Max. oscillatory movement of 100).These bushings have to work without lubrication in abrasive environments and are subjected to severe shocks and vibrations.
Contact pressure between bushing and pen can go up to 45 MPa.
B.Rccommended Bobkay Engg. Plastic Material PET
Because of
- High Compressive strength and excellent creep resistance
- High wear resistance and low coefficient of friction
- Self lubricant making greasing redundant no corrosion problems
C. Advantages of PET bushings over steel equivalent
- No need to grease
- Better wear resistance
- Good machine ability and easy to assemble
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BUSHING FOR RAil BRAKE |
A. Application Description
Rail brakes are used to slow down moving goods wagons. Jaws (10 to 23 m Long) are put at each side of the rail and are closed by means of lever beams which are controlled by hydraulic cylinders. The lever beam articulations are equipped with bushings that slide on stainless steel pens. When the jaws close severe friction occurs between the jaws and the rims of the wagon wheels. The wagon may enter the brake with a maximum speed of about 5 m/s and are slowed down if necessary to speed zero.
B. Recommended Material PET
Because of:
- High Compressive strength and excellent creep resistance
- High wear resistance and low coefficient of friction
- Self lubricant; greasing is redundant
- No corrosion
- No seizing
C. Advantages of PET bushings over steel equivalent
- No need to grease
- Better wear and abrasion resistance
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