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Spider / jaw couplings compensate for parallel, angular and axial displacements.

Mechanical power transmission jaw couplings are torsionally flexible shaft couplings, the operating characteristics of which are two hubs with concave claws, transmitting the torque by meshing with an elastic involute gear ring.

Large stocks for quick delivery and in-house machine shop for exact fit to your application machinery.
Telephone: +44 (0)1737 767493 or email: info@jbj.co.uk
Spider couplings / jaw couplings. One of the best torsionally flexible shaft couplings available that compensate axial, radial and angular misalignment.

Compensate axial, radial and angular misalignment

The flexibility of the elastomer drive ring allows the mechanical power transmission coupling to compensate for parallel, angular and axial displacements.

Suitable for horizontal, vertical and freely selectable mounting positions.

Maximum shaft diameters of 200 mm can be accommodated with maximum torque up to 28,000 Nm continuous (subject to a service factor) & maximum speeds of 19,000 rpm.
» Torsional elasticity.
» Damping.
» Blind assembly.
» Safe against break-down.
» No maintenance.
» ATEX certification on request.
» Hub material: Aluminium (Al), Cast Iron (GG/GGG), Sintered Steel (Si), Steel (St).

Types of Spider / Jaw Coupling Hub

Set screw hub design of spider / jaw couplings
These spider / jaw couplings for mechanical power transmission are torsionally flexible shaft couplings, the operating characteristics of which are two hubs with concave claws, transmitting the torque by meshing with an elastic involute gear ring.

The spider coupling concept gives a reliable, smooth, power transmission without torsional oscillation / vibration and so protects the connected machinery.

Spider coupling with taper bushing

Spider coupling with taper bushing
TRASCO® spider / jaw couplings type for taper bushing SER-SIT®, are manufactured in cast iron GG25.

They combine the typical high performances of standard TRASCO® spider couplings with the advantages of easy mounting and dismounting offered by the taper bushing SER-SIT®.

These hubs are manufactured in two different mounting executions:
B1: installing of tape bushing from outside.
B2: installing of taper bushing from inside (not available for size 90/100).

Spider coupling with shaft locking elements

Spider coupling with shaft locking elements
This execution has been introduced to incorporate advantages offered by the SIT-LOCK® CAL 8 locking elements in the shaft-hub connection.

The system allows for a quick, safe and backlash free mounting without the use of keyway and eliminating the need for lock washers, spacers and stop rings.

Many different solutions may be created to solve all kinds of application needs. We include hereunder a very useful example. In fact, the same hub bore allows the fitting of different shaft diameters.

Spider couplings with intermediate shaft

Spider couplings with intermediate shaft
This spider coupling component set allows the joining of two shafts through two TRASCO® spider couplings and an intermediate shaft length of customized dimension.

The presence of two polyurethane rings allows high dampening capability and greater radial misalignments.

As a standard, hubs are made of cast iron, while shafts are from steel; though, different materials can be used, according to different applications.

Spider coupling with taper bushing

Spider coupling with taper bushing
Combination of the previous two spider coupling component sets allowing the joining of two shafts through two TRASCO® spider couplings and an intermediate shaft length of customized dimension, mounted with shrink discs on the hubs.

The presence of two polyurethane elements allows high dampening capability and greater radial misalignments.

As a standard, hubs are made of cast iron, while shafts are made of steel; though different materials can be used according to different applications.

Flange mounted spider coupling

Flange mounted spider coupling
Spider coupling with flanges developed for applications on heavy machinery and to combine different shafts and flange solutions.

Compact flange spider coupling

Compact flange spider coupling
Similar characteristics as the previous example while being compact in dimension.

Double cardanic spider coupling

Double cardanic spider coupling
The cardanic setup allows compensation of high axial, radial and angular misalignment. The use of the double spider allows for twice the torsion angle and provides very high dampening effect.

Drum brake mounted spider coupling

Drum brake mounted spider coupling
Developed to suit drum brake (FRT) transmission. An elastic coupling consisting of:

» Standard hub (any of Trasco spider coupling range).

» Elastic spider.

» Special hub attached to brake drum.

Also, assembling of different dimensioned brake drum to any kind of coupling is allowed.

Brake disc mounted spider coupling

Brake disc mounted spider coupling
Developed to suit disc-brake (FRD) transmissions.
An elastic coupling consisting of:

» Standard hub (any of Trasco spider coupling range).

» Elastic spider.

» Special hub attached to the brake disc.

Also, assembling of different dimensioned brake discs to any kind of coupling is allowed.

'Ultra temperature' spider inserts

'Utra teperature' spider inserts
Overcome harsh environmental factors from below freezing to blistering heat, UV exposure, and the detrimental effects of salt water.

» Larger Continuous Temperature Range.

» Higher Nominal & Max Torque.

» +10% Radial Misalignment.

» Superior Hydrolysis Resistance.

Note:
Lovejoy© 'Ultra Temp' spider ratings are for sizes 90 to 125.

Link to pdf document
Due to the complete flexibility and ductility of the elastomer ring, it compensates for parallel and angular displacements as well as to absorb longitudinal movement of the shafts.
Each colour denotes spider coupling element specific measured Shore hardness.Standard spider / jaw coupling element information tableSpecial application spider / jaw coupling element information table
Available on request spiders with different compound for special applications:

» High working temperature.
» Heavy working conditions.
» Heavy environment conditions.
» Resistance to specific chemicals.
The involute teeth of the elastomeric inserts are crowned in order to avoid edge pressure on the tooth flanks and so avoid undesirable axial thrust. The puncture proof spider coupling can be loaded extremely high since the elastic elements are submitted to compression and not to bending moments of force. The elastomer gear ring, made of a newly developed polyurethane of various degrees of shore hardness, has important advantages in comparison with the standard polyurethanes. It is non-ageing, with resistance against hydrolysis (can be used in tropical conditions), non-abrasive, has a high self-damping effect and is also resistant to oil and ozone. It can be used with temperatures ranging from -40°C to +120°C.

Spider / jaw mechanical power transmission couplings can be used for horizontal as well as for vertical shaft connections, for reversing, intermittent service and are electrically insulating. The operating characteristics and the durability of the coupling are very positively influenced by the high overall precision of the machining, especially the claws, unbalance is reduced to a minimum, running is improved and service life considerably increased.

Scroll down this page for specification catalogues (link) for straight jaw spider couplings and jaw in-shear type couplings.

Application service factors for the spider / jaw coupling

Application service factor data for the spider / jaw coupling
Total service factor for K = K1 x K2 x K3
flexible shaft coupling misalignment diagram; axial, radial and angular misalignmentjaw coupling displacement data table

Torque ratings for the spider / jaw coupling

* For peripheral speeds of over V = 30 m/s it is necessary to use either steel or SG iron. Dynamic balancing is also necessary.

** When using 64 shore hardness spider, steel and modular iron hubs should be used.

92° shore spiders (yellow) will normally be supplied unless otherwise specified.
jaw coupling data table including dynamic torsional stiffness, torque, max speed, shore hardness, etc.
NOTE: Due to their complexity the tables above may not display well on small, mobile devices.
The technical performance figures above refer to all TRASCO® spider coupling types and are valid for the indicated coupling elements when couplings are properly selected. For particular applications, such as very high chemical resistance,  contact jbj Techniques Limited technical office  telephone: +44 (0)1737 767493 or email: info@jbj.co.uk for spiders available made of special materials.
torsion, damping and resonance information table for standard spider / jaw coupling elements
Increase the life of your spider coupling elements / jaw coupling elements. Get more out of your elastomeric spider by spinning it. When the spider begins to wear, just pull it away from the jaws and advance it around one leg. Only every other leg will show signs of wear because just three of the legs transmit torque. This does not apply if you have a reversing application where the coupling is subject to rotational work, spun in both directions.

Torque limiting with spider / jaw couplings

Torque limiting coupling for protection against overload between two shafts.
Rotary elastic torque limiter can be axially stretched.
Variable elasticity due to different shore hardness of the elastic element of the spider / jaw coupling.
Link to: torque limiting couplings

Backlash Free Spider Couplings

Operation

When the coupling element is installed in its special seats between the hubs, it becomes precompressed, thereby providing the zero backlash feature which characterizes the transmission performance of this coupling. With zero backlash, the coupling remains torsionally rigid within the range of the precompression load, but does permit the absorption of radial, angular, and axial misalignments as well as undesired vibrations. The significantly wide precompressed area of the flexible element keeps the contact pressure against the elastic element low. Therefore, the element teeth can be overloaded many times without undergoing any wear or taking a permanent set.

» Backlash explained link

Advantages

» “zero-backlash” motion transmission.
» dampening (up to 80%) of vibrations from motor shaft.
» low heat and electrical conductivity.
» easy and fast installation.
» perfect balance (A & AP type).
» low moment of inertia (due to compact design and types of materials used).

Main Applications

» servomotors.
» robotics.
» sliding tables.
» spindle controls for drilling and grinding mandrels.
» ball-bearing screws.

Operating Temperature Range

The operating temperature range for the backlash free spider couplings depends on the type of element. For the 92° Sh. A (yellow), the range is between -40 and +90°C, and for the 98° Sh.A (red), the range is between -30 and +90°C. Peak temperatures as high as 120°C can be tolerated for brief instances. High operating temperatures can cause the elastic element to lose a considerable amount of elasticity, thus substantially lowering the torque handling capacity. Therefore, when selecting a coupling, the operating temperature must be carefully considered. See technical characteristics page 3 of the backlash free spider coupling catalogue.
Specification of spider couplings found in this on-line » catalogue « link
Specification of backlash free spider couplings found in this on-line » catalogue « link
Questions?

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