Lovejoy QUICK FLEX QF100 Elastomeric Coupling

Lovejoy QF100 is the size QF100 QUICK FLEX elastomeric coupling: two steel hubs, a radially removable polyurethane insert and a cover, rated 3,177 Nm (28,115 in-lb) continuous with the blue insert and the high-speed cover, with a 75 mm (3 in) maximum bore. Lovejoy positions the QUICK FLEX as a replacement for gear, grid and other elastomeric couplings in both high- and low-torque drives.

An insert-in-shear coupling that replaces gear and grid types

QUICK FLEX has no metal-to-metal contact between opposing hubs, so hubs and shafts may remain intact when the insert is changed. The design dampens torsional vibration and shock, accepts misalignment up to 2 degrees on this size, and is inherently balanced by precision machining for high-speed use. Lovejoy lists duties such as motor to gearbox (low torque, high speed), gearbox to driven equipment (high torque, low speed), motors to pumps, and any drive shaft to a driven shaft.

The catalogue covers fifteen sizes with maximum bores up to 505 mm, continuous torque from 43 Nm to 610,529 Nm, shaft separations of 25.4 mm to 3,048 mm using spacer couplings, and four bore styles: bored with keys and set screws (clearance or interference fit), bushing style, splined and mill-motor.

Technical specifications of the QF100 with high-speed cover

With the high-speed split cover the QF100 continuous torque is 2,003 Nm (red), 3,971 Nm (blue and white) and 6,061 Nm (black).

Insert materials

QUICK FLEX sizes with high-speed cover

Selecting a QF size

Design torque is actual torque x service factor, with actual torque 63,025 x HP / RPM in in-lb or 9,550 x kW / RPM in Nm. Catalogue service factors include 1.25 for centrifugal fans and compressors and agitators, 1.5 for centrifugal blowers and lobe compressors, 1.75 for belt, screw and flight conveyors, and 3.0 for one- and two-cylinder reciprocating compressors. For engine drives use the engine service factor in catalogue Table 1. The catalogue also lists a coupling cover choice: high-speed, high-speed split, aluminium high-performance, and low-speed split.

Installation and operation notes

On QF250 and larger sizes the covers are fixed by eight bolts; up to QF175 the hubs are machined with snap-ring grooves. Keep alignment well within the tolerance table, avoid sudden shock loads, and check the insert and cover shortly after commissioning. Insert chemical compatibility is tabulated in the catalogue for oils, fuels and many chemicals; steam, strong acids and several solvents are rated severe for urethane.

Where it is used

Mud pumps, roller tables, pulp and paper drives and general motor-pump sets are the success stories Lovejoy publishes; the stainless version targets food washdown. Compare with a pin-type solution such as the Flender N-EUPEX pin coupling.

Operating notes for Oman and the GCC

QUICK FLEX couplings are a common upgrade on gearbox, pump and conveyor drives in cement, mining, water and oil and gas plants, where replacing a gear or grid coupling removes the need for regular lubrication. The insert can be changed without moving the hubs, which shortens downtime on remote or critical machines. Check the insert colour and material against the torque and the operating temperature, keep a spare insert at site, and look at the insert during routine checks, because heat, sand and misalignment shorten its life.

Information to send with an enquiry

• Motor power, speed and the driven machine
• Shaft sizes and keyways, or the existing coupling to be replaced
• Insert type and cover style needed
• Shaft separation and any spacer requirement

Frequently asked questions

How is a QUICK FLEX insert replaced?

The polyurethane insert is radially removable under the cover, so the hubs and shafts stay in place and the driving and driven machines need not be moved.

Which insert is used for high temperature?

The white insert is a heat-resistant urethane with a 60D hardness and an operating range of -50 to 177 C (-60 to 350 F); red, blue and black inserts are rated -50 to 100 C.

Can the black insert be used with the high-speed cover?

The catalogue does not recommend it. For high torque with a black insert use a split cover option.

How much misalignment does the QF100 allow?

Radial 1.47 mm (0.058 in), axial 3.96 mm (0.156 in) and angular 2 degrees, per the misalignment tolerance table.

Are stainless versions available?

Yes. Lovejoy offers a stainless-steel version of each coupling for corrosive or washdown environments.

Documents and quotation

The QUICK FLEX full catalogue (10509 Rev E) is hosted on this page. See Couplings and Shaft Locking Devices. Seven Star LLC is an independent supplier in Muscat; send size, bores, keyways, cover style and insert colour for a quotation.