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LaqnicanJoint (Mechanical Joint)

LaqnicanJoint improves efficiency in piling work


  • Bridge foundations
  • Harbor structures
  • River structures
  • Earth retaining walls


Field Joint System Realizing Full-Strength Connection
Laqnican Joints can ensure full-strength connection without being affected by weather conditions or operator skills. (Steel pipes with Laqnican Joints have strength and deformation capacities equivalent or superior to those of steel pipes with no joints.)
→High-quality field connection is available
Rapidly Connects Pipes Having a Large Diameter and Wall Thickness
Connection work takes only a short time, regardless of pipe size. You can field-joint pipes of different thicknesses.
→Shortens the construction period
Easy Connection
Just fit one joint into another and tighten the bolts for pushing and fixing key. No special skills or qualifications are required.
→Anyone can connect pipes with ease
Easy Construction Quality Control
Just check the depth of tightened bolts for pushing and fixing key with a depth gauge. No special testing tools are needed for connection checks and work quality control.
→100% inspection of joint connections


Step type Flat type
Laqnican Joint conceptual drawing

A Laqnican Joint consists of a box joint, pin joint, load transfer keys, and bolt for pushing and fixing key. The box joint has one or more grooves in the inner circumference containing (circumferentially split) arc-shaped plates, called "load transfer keys." These keys are pushed toward the pipe center when the bolts for pushing and fixing key are turned. The pin joint has grooves on the outer circumference which are positioned to align with the box joint grooves.

To connect two steel pipes, set the box joint (which is circumferentially factory-welded to the upper steel pipe pile) onto the pin joint (which is circumferentially factory-welded to the lower steel pipe pile), and turn the bolts for pushing and fixing key to push the load transfer keys held in the box joint grooves into the pin joint grooves. This assembles all parts into an integral joint and completes connection of the two steel pipes. After assembly, Laqnican Joint connections can be 100% inspected by checking the depths of the tightened set bolts. Furthermore, a "rotation suppression key" on the outer surface transmits the rotational torque in the piling work. Where the impact driving or vibro-hammer method is used, a measure to control bolt for pushing and fixing key loosening (such as a stop ring) is used.

Procedure & Advantages

Laqnican Joints Shorten Operation Time

You need only:
about 5 minutes for field connection, and
about 3 minutes for quality control.

Lately, steel pipe piles of large diameters and wall thicknesses are being used in a growing number of foundation designs. This means that welding operations account for an increasingly large proportion of the total working hours needed for construction. Taking only about five minutes for each connection, regardless of steel pipe diameter and wall thickness, Laqnican Joints can shorten the time required for connecting steel pipe piles and thus significantly reduce costs by shortening the overall construction period.

Laqnican Joint Connection Procedure
1. Suspend the upper pile→2.Align positions→3. Fit box and pin joints→4.Remove bolts for temporary fixing key→5.Fit bolts for pushing and fixing keyand tighten→6.Now, all bolts have been tightened→7.Check with a depth gauge→8.The Laqnican Joint connection has been checked

Disconnecting a Laqnican Joint
1.Before disconnecting→2.Remove bolts for pushing and fixing key→3.Set hexagonal socket bolts to load transfer keys→4.Draw load transfer keys into the box joint→5.Now, the joint is disconnected

Examples of Applicable Piling Construction Methods

Impact driving construction method Vibro-hammer construction method Steel-pipe soil-cement composite pile construction method Rotary press-in construction method (360 degrees) Rotary penetration construction method Press-in construction method Inner excavation construction method Hydraulic full-slewing inner excavation construction method


Harbor construction work Railway construction work Steel pipe sheet pile foundations Temporary platform pillars Road construction work

Related Industries

Lately, as a part of protective measures against natural disasters, steel pipe piles have been getting increasingly larger, in both diameter and wall thickness. Our mechanical joints enable quick jointing of steel pipe piles and steel pipe sheet piles with no on-site welding required, which contributes to the realization of stable quality, shorter work periods, lighter workloads, and reduced construction costs.

Contact Us

To inquire about a product, service, maintenance, or any other matter, please contact your nearest Kubota location directly by phone or contact us by email. Before making an inquiry, we recommend that you check out our customer support information, including FAQs, as you might be able to find the answer to your question more quickly there.