Tyre Couplings F85 - Industrial Tyre Couplings

Size	TYPE F & H								TYPE B								A	C	‡ G	† M	No. of screws per flange
Size	Bush No.	Max Bore	L	D	E	F	ξ J	Approx Weight Kg *	Max Bore	Min Bore	L	D	E	F	Set Screw on key	Approx Weight Kg *	A	C	‡ G	† M	No. of screws per flange
F85	2012	50	112	103.0	32	53.5	47	12.5	70	31.75	154	103	53	53.5	M12	14.0	222.0	179	13	48	6

The F85 Tyre Coupling is a specialized intermediate size in the flexible coupling range, bridging the gap between the standard F80 and F90 models. It provides engineers with a precise torque solution (nominally 305 Nm), allowing for optimized drive selection without unnecessary oversizing.

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Key Specifications

The F85 offers a targeted performance profile for medium-to-heavy industrial drives. Below are the standard technical specifications:

Parameter	Value
Model Size	F85
Nominal Torque	305 Nm
Max. Torque (Peak)	915 Nm
Max. Rotational Speed	3,000 RPM
Power Rating (at 1440 RPM)	~46 kW (approx)
Taper Lock Bush Size	2012
Max. Bore Size	50 mm (with 2012 Bush) / 70 mm (Max with B Flange)
Misalignment Capability	4° Angular \| 2.2mm Parallel \| 2.8mm End Float

How It Works

The F85 operates using the proven torsionally elastic "tyre" principle:

Torque Transmission: The coupling transmits power through the shear resistance of the rubber tyre. This design eliminates backlash and prevents the transmission of high-frequency vibrations to the driven machine.
Intermediate Sizing: By offering a nominal torque of 305 Nm (compared to 253 Nm for the F80), the F85 allows for safer operation on drives that sit right on the limit of the smaller size, ensuring longevity without the cost of moving to the much larger F90.
Element Flexibility: The tyre flexes to handle simultaneous parallel (up to 2.2mm) and axial misalignment, significantly reducing side loads on motor bearings.

Benefits of F85 Couplings

Optimized Capacity: Provides ~20% more torque capacity than the F80, offering a safety margin for demanding medium-duty applications.
Maintenance Friendly: The "replace-in-place" split tyre allows for quick element changes without disturbing the motor or pump alignment.
Lubrication Free: No metal-to-metal contact means no grease points, reducing maintenance routines to simple visual inspections.
Shock Damping: The rubber element effectively isolates shock loads from crushers or reciprocating machinery, acting as a buffer for the drivetrain.
Standard Fitment: typically uses the common 2012 Taper Lock bush, making it compatible with existing shaft setups often used for F80s.

Typical Applications

The F85 is frequently used in specific industrial setups where precise sizing is critical:

Rolling Mills: Auxiliary drives and roller tables.
Pumping Stations: Medium-large centrifugal pumps requiring vibration isolation.
Compressors: Industrial air compressors with high start/stop frequencies.
Conveyors: Belt drives in cement and aggregate plants.
Mixers: Agitators in chemical processing.

Summary

The F85 Tyre Coupling serves as a vital problem-solver in the power transmission lineup. With a robust 305 Nm nominal torque capacity and the ability to handle up to 3,000 RPM, it is the perfect choice for applications that demand more than an F80 can handle but do not require the bulk of an F90. Its lubrication-free, shock-absorbing design ensures reliable operation and low total cost of ownership.