Drop-in replacement for grid spacer couplings

Edited by the Engineeringtalk editorial team Apr 25, 2002

The novel JIS 6-Pin range of jaw in-shear elastomeric couplings from Lovejoy introduces a JIS spacer-type series intended as non-lubricated, drop-in replacements for grid spacer couplings.

The novel JIS 6-Pin range of jaw in-shear elastomeric couplings from Lovejoy improves the no-tools elastomeric element locking system, adds six larger sizes extending maximum bore up to 9in (229mm), and introduces a JIS spacer-type series intended as non-lubricated, drop-in replacements for grid spacer couplings.

New JIS 6-Pin couplings are named for Lovejoy's patent-pending next-generation mechanism for locking the elastomeric element in place.

The element, moulded as a wrap-around strip, positions elastomeric cushions to span the shear-plane between the jaws of driving and driven hubs.

A wide, flat stainless-steel locking ring slides on over the strip to hold it in place.

Six tooth-like pins extending inward around both sides of the ring, three per side, keep the ring straddled over the elastomeric strip.

Three crosswise grooves moulded into the strip around its perimeter provide passageways for the pins as the ring slides on.

When the installed ring is rotated a few degrees, the pins latch behind small bumps moulded along one side of the strip, which prevent unintended return rotation of the ring.

The new JIS 6-Pin element and ring fit Lovejoy's industry-standard jaw coupling hubs, converting them from normal in-compression service to in-shear service.

The new element offers the advantage of working with both new and old ring designs.

This interchangeability simplifies the user's parts stocking requirements.

The element's wrap-around, radially removeable design shortens element-replacement downtime by eliminating any need to disassemble hubs, even enabling "blind fit" in confined spaces.

Converting to in-shear service doubles the standard jaw coupling's angular misalignment capability to 2 degrees and its parallel misalignment capability to 0.030-0.094in, depending on size, while adding torsional wind-up of 5 degrees at full load for greater vibration-damping action.

In-shear operation also allows the torque-transmitting cushions to serve as a fuse that can break away to disconnect the hubs and prevent system damage in the event of torque overload.

Further extending the versatility of JIS 6-Pin couplings, new spacer designs fill BSE (between shaft end) gaps of 3.5, 5, 7 and 9in (89, 127, 184 and 229mm), with maximum bores up to 5.5in (140mm), depending on coupling size.

Drop-out spacers can help simplify system maintenance by avoiding the need to demount and then realign driving or driven equipment.

Designed for pump applications, Lovejoy spacers accommodate American and European industry standard pump/motor shaft separations.

Made of Type 347 cast stainless steel, the new JIS 6-Pin ring can team up with Lovejoy's stainless-steel jaw hubs to provide a totally stainless coupling for applications that require high moisture/corrosion resistance.

Lovejoy offers stainless steel hubs produced by either investment casting or sintered powder, with savings ranging from 50-90% over the previous manufacturing process of machined bar stock hubs, and with immediate availability.

For corrosion-sensitive applications requiring light weight, low overhung load and/or low inertia, the new JIS 6-Pin ring and element also can be combined with Lovejoy's AL Type aluminium hubs.

The JIS 6-Pin element is made of 50D shore urethane material with maximum temperature rating of 93C.

A total of 16 hub/ring/element sizes serve maximum torque requirements up to 41,428Nm in biggest size, at maximum speeds up to 9200rev/min in smallest size.