PU Spider Inserts for Jaw Couplings | ML, MT, GR, GS, HRC Series

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PU Flexible Coupling Spider Inserts – ML, MT, GR, GS, HRC Series

Model Number
Check below, custom

ML, MT, GR, GS, HRC

Product Description

PU Flexible Coupling Spider Inserts – ML, MT, GR, GS, HRC Series

Factory Direct | High-Strength Polyurethane (PU/TPU) | Oil & Wear Resistant | -40°C to 100°C | 22.4–2500 N·m Torque | Maintenance-Free | OEM Customizable

The Apexcoupling spider insert series offers a comprehensive range of high-performance polyurethane elastomer inserts for flexible jaw/plum couplings. Available in ML, MT, GR, GS, and HRC series, these inserts are the heart of your coupling system – transmitting torque, absorbing shock, dampening vibration, and compensating for misalignment.

Manufactured from high-strength thermoplastic polyurethane (TPU) with excellent oil resistance, wear resistance, and a wide operating temperature range, our spider inserts provide 3-5x longer service life than standard rubber elements. Backlash is eliminated by the press fit of the elastomer into the hubs, ensuring precise, maintenance-free power transmission for your machinery.

✅ Oil-resistant & wear-resistant polyurethane. Maintenance-free – no lubrication required. Wide temperature range -40°C to +100°C. Direct replacement for KTR, Lovejoy, and other standard couplings. OEM custom sizes and hardness available.

Quick Selection Guide – Which Spider Insert Do You Need?

Series	Shape / Type	Applications	Key Features
ML Series	Plum blossom (梅花型)	Rolling mills, cranes, forging presses, petroleum equipment	Plum-shaped coupling cushion
MT Series	Plum blossom (梅花型)	Pipes, excavators, large equipment, heavy machinery buffers	Polyurethane plum-shaped elastomer
GR Series	Star-shaped (星型)	Steel rolling, lifting, forging, petroleum, large equipment	Star-shaped elastic coupling
GS Series	Curved jaw / star	Jaw couplings, zero-backlash applications, high-speed	KTR Rotex replacement; Straight center tooth for higher stiffness
HRC Series	Star / hexagonal	Pipes, excavators, large equipment, mechanical shaft cushioning	HRC coupling insert; Design variants: F (internal taper), H (external taper), B (pilot bore)

💡 Selection tip: Identify your coupling type and model number, then match to the corresponding spider series. For custom applications, we offer non-standard sizes and hardness grades.

ML Series – Plum Blossom Spider Insert

The ML series features a plum blossom (梅花型) shaped elastomer designed for cushioning of various heavy machinery coupling shafts. Widely used in rolling mills, cranes, forging presses, petroleum equipment, and other various mechanical equipment for connecting transmission shaft ends.

Model	Outer Diameter (mm)	Inner Diameter (mm)	Thickness (mm)	Flaps
ML1	48	19	12	4
ML2	68	28	18	6
ML3	82	34	18	6
ML4	100	42	20	6
ML5	122	52	25	6
ML6	140	64	30	6
ML7	166	90	30	8
ML8	196	100	35	10
ML9	225	115	35	10
ML10	255	140	45	10
ML11	296	170	50	10
ML12	356	215	55	12
ML13	391	250	55	12

📐 Non-standard ML sizes available upon request. Contact our engineering team for custom sizing.

MT Series – Polyurethane Spider Insert

The MT series is a polyurethane plum-shaped elastomer used in the middle of the coupling to play the role of shock absorption, insulation and buffering to transmit torque. Suitable for coupling large equipment and various mechanical buffers to drive shafts, widely used for pipes, excavators, and large equipment.

Model	Outer Diameter (mm)	Inner Diameter (mm)	Thickness (mm)	Flaps	Weight (g)
MT-1	48	19	12	4	15
MT-2	68	28	18	6	45
MT-3	82	34	18	6	62
MT-4	100	42	20	6	105
MT-5	122	52	25	6	180
MT-6	140	64	30	6	270
MT-7	166	90	30	8	365
MT-8	196	100	35	8	570
MT-9	225	115	35	10	850
MT-10	255	140	45	10	1200

📐 Non-standard MT sizes available upon request. Color options: Green, Blue, Natural.

GR Series – Star-Shaped Elastic Spider Insert

The GR series features a star-shaped elastic coupling design, widely used for connecting the drive shaft ends of steel rolling, lifting, forging, petroleum and other large equipment. Made from high-strength polyurethane elastomer offering superior resistance and bending capabilities with excellent oil resistance.

Model	Outer Diameter (mm)	Inner Diameter (mm)	Height 1 (mm)	Height 2 (mm)	Flaps
GR-19	40	18	14.5	12	6
GR-24	54	26	15.2	14	8
GR-28	65	30	19	15	8
GR-38	80	38	22	18	8
GR-42	95	46	24	20	8
GR-48	104	51	25.5	20.5	8
GR-55	120	60	27	22	8
GR-65	135	68	32	26	8
GR-75	161	81	37	30	10
GR-90	199	100	42	34	10
GR-100	224	111	–	38	10

GS Series – Curved Jaw Spider Insert

The GS series features a straight center of the spider tooth, providing higher stiffness due to coupling prestress. The crowning of the ends of the spider legs allows for misalignment, while the curved jaws and solid spider center provide high-speed capability. Designed for zero-backlash applications with preloaded spider. A direct replacement for KTR Rotex elastomer.

Model	Outer Diameter (mm)	Inner Diameter (mm)	Height (mm)	Flaps
GS-19	40	18	14.5	6
GS-24	54	26	15.2	8
GS-28	65	30	19	8
GS-38	80	38	22	8
GS-42	95	46	24	8
GS-48	104	51	25.5	8
GS-55	120	60	27	8
GS-65	135	68	32	8
GS-75	160	80	37	10

HRC Series – Coupling Spider Insert

The HRC series is designed for application in mechanical shaft couplings, providing a buffer effect at the transmission shaft joint to ensure seamless and efficient operation. Available in multiple design variants:

F design: Internal taper lock fit
H design: External taper lock fit
B design: Pilot bore – can be machined to customer specifications

Model	Max Bore (mm)	Dimensions (mm)	Weight (kg)
HRC-70	32	A:69, B:60, E:31, F:25, G:18, C:20, D:23.5, L:65	1.2
HRC-90	42	A:85, B:70, E:32, F:30.5, G:22.5, C:19.5, D:23.5, L:69.5	1.4
HRC-110	55	A:112, B:110, E:45, F:45, G:29, C:18.5, D:26.5, L:82	6
HRC-130	60	A:130, B:105, E:50, F:53, G:36, C:18, D:26.5, L:89	6.55
HRC-150	70	A:150, B:115, E:62, F:60, G:40, C:23.5, D:33.5, L:107	8.53
HRC-180	80	A:180, B:125, E:77, F:73, G:49, C:34.5, D:46.5, L:142	19.92
HRC-230	100	A:225, B:155, E:99, F:85.5, G:59.5, C:39.5, D:52.5, L:164.5	31.2
HRC-280	130	A:275, B:206, E:119, F:105.5, G:74.5, C:51, D:66.5, L:207.5	60

📐 Custom dimensions and non-standard sizes available. Contact our engineering team for custom sizing.

Product Features & Advantages

Advantage	Benefit
High-Strength Polyurethane (TPU)	Excellent tensile strength, wear resistance, and elastic resilience – 3-5x longer service life than rubber
Oil & Chemical Resistant	Highly resistant to mineral oils, fuel oil, and mechanical oil – non-corrosive
Wide Temperature Range	-40°C to +100°C – suitable for extreme operating conditions
Low Abrasion	Abrasion <0.05 cm³/1.61 km – long service life
Zero Backlash	Press fit eliminates backlash – precise torque transmission
Maintenance-Free	No lubrication required – reduces operating costs
Multiple Hardness Grades	80 Shore A to 98 Shore A – optimize torsional characteristics
Easy Replacement	Quick and cost-effective – restore coupling performance without hub removal
Wide Size Range	ML1-ML13, MT1-MT10, GR19-GR100, GS19-GS75, HRC70-HRC280 – covers all standard coupling sizes
OEM Customization	Custom sizes, Shore hardness, and colors available

Applications

Rolling Mills – Steel and metal processing
Cranes & Hoists – Lifting and material handling
Forging Presses – Heavy industrial presses
Petroleum Equipment – Oil and gas machinery
Mining Equipment – Crushers, feeders, conveyors
Excavators & Construction – Heavy equipment drives
Pumps & Compressors – Industrial pumps and compressors
Conveyors – Material handling systems
Paper Machinery – Paper production equipment
Textile Machinery – Spinning and weaving equipment

Why Choose Apex Coupling for Spider Inserts?

Advantage	Description
Factory Direct	Competitive B2B pricing – no middlemen
Premium PU Material	High-strength TPU – 3-5x longer life than rubber
Wide Model Range	ML, MT, GR, GS, HRC – covers all standard coupling sizes
KTR Rotex Replacement	GS series direct replacement for KTR Rotex elastomer
Oil & Wear Resistant	Excellent resistance – ideal for harsh environments
Wide Temperature Range	-40°C to +100°C – suitable for extreme conditions
OEM Customization	Custom sizes, Shore hardness, and colors
Quick Replacement	Easy installation – restore coupling performance without hub removal

FAQ

Q: What is a spider insert (coupling cushion)?
A: A spider insert (also called a coupling cushion, elastomeric spider, or plum blossom pad) is the flexible element that fits between the two hubs of a jaw/plum coupling. It transmits torque, absorbs shock, dampens vibration, and compensates for misalignment.

Q: What is the difference between ML, MT, GR, GS, and HRC series?
A: Different series correspond to different coupling designs and applications. ML and MT are plum blossom types for heavy machinery. GR is star-shaped for rolling mills, lifting, forging. GS is for zero-backlash, high-speed jaw coupling applications. HRC is for mechanical shaft couplings with multiple design variants.

Q: What materials are used?
A: The spider inserts are manufactured from high-strength thermoplastic polyurethane (TPU) – offering excellent wear resistance, oil resistance, and long service life.

Q: What is the temperature range?
A: The standard operating temperature range is -40°C to +100°C.

Q: What is the torque range?
A: The standard torque range covers 22.4 – 2500 N·m.

Q: Is the spider oil-resistant?
A: Yes. Polyurethane is highly resistant to oil, including fuel oil and mechanical oil – non-corrosive.

Q: Does the spider require lubrication?
A: No. The spider is maintenance-free – no lubrication required.

Q: What Shore hardness options are available?
A: Standard hardness grades include 80 Shore A, 92 Shore A, 95 Shore A, and 98 Shore A. Custom hardness available on request.

Q: Can I get a custom spider?
A: Yes. We offer OEM customization – custom sizes, Shore hardness, and colors available.

Q: Is this a replacement for KTR Rotex?
A: Yes. The GS series is a direct replacement for KTR Rotex elastomer.

Request a Quote

Send us your series (ML, MT, GR, GS, or HRC), model, Shore hardness preference, and application details. Our engineers will recommend the optimal spider and provide a quotation within 24 hours.