| Coupling | Power Rating | Pilot Drill Size | Max. Bore D | ØA | Length thru' Bore L1 | ØB | Gap G | ØE | DBSE | Overall Length TL1 | |||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Type | Size | Synthetic Rubber | Polyurethane | H-Trans | SW/ RRS | L | |||||||||||
| Rated Torque (Nm) | kW@ 100 rpm | Rated Torque (Nm) | kW@ 100 rpm | Rated Torque (Nm) | kW@ 100 rpm | ||||||||||||
| 70 | 4.90 | 0.05 | 7.4 | 0.08 | 12.3 | 0.13 | - | 20 | - | 35 | 19 | - | 35 | 2 | - | - | 51 |
The L 70 Jaw Coupling is a standard "L-Series" flexible shaft coupling designed for light to medium-duty power transmission. It is a three-piece assembly consisting of two interlocking hubs and a flexible central insert known as a spider. The L 70 is widely recognized for its "fail-safe" design—meaning that if the spider fails, the metal jaws of the hubs will interlock to continue transmitting power (albeit with noise) until the machinery can be safely shut down.
According to the technical table provided, the L 70 model has the following specific ratings based on the type of spider material used:
| Specification | Synthetic Rubber | Polyurethane | H-Trans |
| Rated Torque (Nm) | 4.90 | 7.4 | 12.3 |
| Power @ 100 rpm (kW) | 0.05 | 0.08 | 0.13 |
Max Bore (D): 20 mm
Outside Diameter (ØA): 35 mm
Overall Length (TL1): 51 mm
Gap (G): 2 mm
Length thru' Bore (L1): 19 mm
Hub Diameter (ØB): 35 mm
Assembly: Two metal hubs are mounted onto the ends of two shafts (e.g., a motor shaft and a pump shaft).
The Spider: The flexible spider is placed between the "jaws" of the two hubs.
Torque Transmission: As the motor rotates, the jaws of the drive hub push against the arms of the spider, which in turn push against the jaws of the driven hub.
Flexibility: The spider material compresses to absorb shocks and compensates for small misalignments between the two shafts without causing damage to bearings or motors.
Misalignment Compensation: Naturally handles angular, parallel, and axial shaft misalignments.
Vibration Damping: The elastomeric spider absorbs vibrations, leading to quieter operation and longer machine life.
No Lubrication: Unlike gear or chain couplings, jaw couplings require no oil or grease.
Cost-Effective: Simple design and low maintenance costs make it one of the most popular couplings in the industry.
Fail-Safe: The interlocking jaw design ensures power transmission continues even if the spider is destroyed.
The L 70 size is ideal for small to mid-sized industrial equipment, including:
Centrifugal Pumps: Connecting electric motors to water or chemical pumps.
Conveyors: Light-duty belt and roller conveyor systems.
Fans and Blowers: HVAC systems and industrial ventilation.
Gearboxes: Connecting small reducers to driven machinery.
Machine Tools: Small lathes, milling machines, and wood-working equipment.
The L 70 is a versatile and reliable coupling choice for shafts up to 20 mm in diameter. Depending on your torque needs, you can choose between Synthetic Rubber (for maximum damping) or H-Trans (for maximum torque capacity of 12.3 Nm). Its compact 35 mm diameter and easy "no-maintenance" design make it a staple in general mechanical engineering.
