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Jaw and Spider Couplings

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Jaw couplings are a type of shaft coupling that are used for rotational power transmissions. They are used to transmit torque between two shafts and help protect components from damage by dampening the shock and vibrations. Jaw type couplings feature two aluminum alloy hubs with protruding lugs known as “jaws,” and a polyurethane elastomer insert known as a “spider” that fits in-between the hubs.

Polyurethane elastomer spiders offer a higher load capacity than other coupling materials and are designed to provide either a loose or tight fit. The elastomer material also provides good resistance to oils and chemicals, also offering electric isolation between both shafts. Jaw and spider couplings have different torque ratings determined by the hardness (durometer) of the elastomer spider, making them suitable for a wide range of mechanical applications.

Miki Pulley offers jaw & spider couplings with pilot bore, keyed, or clamp style hubs. There are three different elastomer spider options. Request a quote for your jaw couplings today or contact us for assistance choosing the correct coupling for your performance requirements.

ALS-R (Tight fit elastomer)


Tight fit elastomer

ALS-Y (Medium fit elastomer)


Medium fit elastomer

ALS-B (Loose fit elastomer)


Loose fit elastomer





ALS-R model

ALS-R Jaw and Spider Couplings

The ALS-R model utilizes a 97 JIS A hardness polyurethane elastomer spider, with the spider profile and fit designed with a tight fit to allow no backlash.

  • Maximum working torque: 387.22 ft-lbs, (525Nm)
  • Hole diameter range: 0.118” ~ 2.362”, (3mm ~ 60mm)
  • Ambient operating temperature: -22F ~ 176F, (-30 ℃ ~ 80 ℃)
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ALS-Y model

ALS-Y Jaw and Spider Couplings

The ALS-Y model utilizes a 90 JIS A hardness polyurethane elastomer spider, with the spider profile and fit designed to allow no backlash. This coupling may be used in applications from general purpose motor connections, to simple servo applications with high torque. The element is of a lower hardness than the ALS-R, thereby suppressing axial reaction force.

  • Maximum working torque: 228.64 ft-lbs, (310Nm)
  • Hole diameter range: 0.118” ~ 2.362”, (3mm ~ 60mm)
  • Ambient operating temperature: -22F ~ 176F, (-30 ℃ ~ 80 ℃)
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ALS-B coupling

ALS-B Jaw and Spider Couplings

The ALS-B model utilizes a 97 JIS A hardness polyurethane elastomer spider, with the spider profile designed for a loose fit. This allows for misalignment while providing high torque transmission.

  • Maximum working torque:  387.22 ft-lbs,   (525Nm)
  • Hole diameter range:  0.315” ~ 2.362”,  (8mm ~ 60mm)
  • Ambient operating temperature:    -22F ~ 176F,  (-30 ℃ ~ 80 ℃)
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ALS-B coupling

ALS-SGN Jaw and Spider Couplings

  • Maximum RPM: 22,000
  • Maximum transmittable torque: 810 Nm (597 ft-lbs )
  • Ambient operating temperature: -40 C-120 C (-40 F – 248 F)

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ALS-B Jaw Spider Coupling


AL-SPR Jaw and Spider Couplings

This simple jaw and spider coupling features a nitrile rubber element between two sintered aluminum hubs. Using aluminum in the hubs decreases moment of inertia on starts and stops. AL couplings are available in standard bore sizes with key and setscrew, or pilot bore. Bores may also be machined to customer specifications upon request.

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Different Types of Element | Jaw & Spider Couplings | Jaw Couplings | Elastomer Couplings

Polyurethane Elastomer Jaw Coupling Options

Miki Pulley’s ALS elastomer couplings are a simple jaw & spider shaft coupling with sintered aluminum alloy hubs and polyurethane elastomer spider elements. Customers may choose from with three different spider element options and three hub styles, depending on your performance requirements. Our elastomer jaw couplings may be used in applications from general purpose motor connections, todemanding servo applications with high torque.

We offer a range of jaw & spider couplings to create coupling combinations that meet the needs of a wide range of applications.  The curved profile of the element allows for pre-compression with no backlash and our elastomer spiders are designed to provide a loose or tight fit.

Our spider element options are as follows:

  • ALS (-R) Type: a high torque, high-responsive model that provides a tight fit with a no-backlash design, with little capacity for mis-alignment.
  • ALS (-Y) Type: provides a good balance of torque transmission performance, flexibility and responsiveness and features a tightly fitting, zero-backlash design.
  • ALS (-B) Type: provides a loose fit with a high torque, flexible design, and larger mis-alignment capacity.

Our aluminum alloy jaw coupling hubs are offered in the following configurations:

  • Pilot Bore: Less costly option, allowing the customer or end user to machine the bore to their specifications.
  • Key/Set Screw Type: to help enable high transmission torque
  • Clamp Type: designed for easy mounting and removal


Types of Elastomer Couplings | Types of Jaw & Spider Couplings

Advantages of Jaw & Spider Elastomer Couplings

Jaw and spider couplings from Miki Pulley transmit up to 387 ft-lbs. (525 Nm of torque) and are offered with three types of spider elements to provide the jaw coupling fit your application requires. Our fail-safe elastomer couplings are designed for long service life and robust performance. 

Miki Pulley elastomer jaw & spider couplings have several advantages, including:

  • Shape that reduces mounting error counterforce
  • High load capacity and torrential stiffness for higher torque ratings
  • Quieter operation
  • Zero backlash (ALS (-R) and ALS (-Y) type spiders only)
  • Simple design that is easy to install and disassemble

Request a Quote for Elastomer Jaw Couplings

We provide elastomer jaw & spider couplings to meet your application requirements. Request a quote for jaw type couplings or contact us for additional information.