Engineering for highest loads
Design for easy handling
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We are an experienced Swiss engineering company with a focus on globally unique bolting solutions based on the MJP principle (mechanical Multi-Jackbolt Pretensioner) for absorbing the greatest forces.
PLOKE Multi-Jackbolt Pretensioners (MJP) are the ideal solution for large screw connections (≥ M16) where a defined pre-tensioning force needs to be generated and reliably maintained – and also easily released again! They are designed according to ISO 898-2 and are used for general screw connections in all areas of industry.
With PLOKE Multi-Jackbolt Pretensioners (MJP), an extremely advantageous geometry is achieved purely mechanically: The pretensioning force acts purely axially and no torsional loads occur during pretensioning, so that pretensioning to 90% of the yield strength can be achieved effortlessly. For the user, this means that compared to other tensioning methods, a better load distribution in thread and support as well as lower stress peaks and thus lower settlements are achieved. The bolt cross-section of the main thread can be loaded higher and the risk of failure decreases.
In addition, due to the compact design and the resulting weight reduction, new constructions can be designed with an alpha factor >1.2, which leads to an overall more compact bolted connection with a correspondingly slimmer overall design and, at the same time, more built-in safety.
Due to the captive mounted Mammoth™ Jackbolts, PLOKE Multi-Jackbolt Pretensioners are thus ideally suited for highly dynamic applications such as turbine impellers.
The defined pretensioning force is generated by the systematic tightening of the Mammoth™ Jackbolts. Due to the special shape of these Jackbolts, on the one hand the largest possible pressing surface is achieved, and on the other hand, due to the small friction radii, only a minimum clamping torque MA is required, which can be easily achieved with simple hand tools. The final pretensioning force FV in the screw bolt (main thread) consequently corresponds to the sum of the Jackbolt forces; it is purely axial and thus torsion-free. The clamping force of the connection results from the compressive force of the Mammoth™ Jackbolts and the reaction force in the screw bolt.
PLOKE Multi-Jackbolt Pretensioners (MJP) are basically not subject to any wear and can therefore be pretensioned, loosened and retensioned as often as required.
Since bolted connections with PLOKE Multi-Jackbolt Pretensioners (MJP) can be loosened and retensioned extremely quickly and only small forces are used, only the shortest downtimes result for the user both when replacing conventional bolted connections and during maintenance work on the plant. This in turn means great financial advantages due to the significant increase in the availability of production plants.
In addition, when bolting with PLOKE Multi-Jackbolt Pretensioners (MJP), simple and commercially available hand tools (torque wrenches) can be used. Special tools are not required and a short introduction of the operating personnel is sufficient.
Another plus is the external hexalobular head (Torx®) of the Mammoth™ Jackbolts: this is extremely wear-resistant and safe to handle, which contributes to work safety.
PLOKE Multi-Jackbolt Pretensioners (MJP) are protected by patent:
We offer our services and products throughout Europe. Our customers are advised personally and competently on site by our sales engineers and distribution partners and are also supported during the installation of their bolting solution or during maintenance work. Benefit from our many years of experience as a technology leader for highly stressed large diameter screw joints.
We calculate, develop, design and produce the best technical and economical bolting solutions for large dimensions and high, precisely adjustable and releasable pretensioning forces in accordance with the specific requirements of our customers and on the basis of our high-quality mechanical Multi-Jackbolt Pretensioners (MJP).
Mechanical Multi-Jackbolt Pretensioners (MJP) are the perfect solution for purely axial pretensioning.
MJP are designed according to ISO 898-2 and are used for highly loaded bolting applications in all areas of industry.
Due to the captive mounted Mammoth™ Jackbolts they are best suited for highly dynamic applications.
The unbeatable combination of all advantages for combined axial and radial pre-tensioning of highly dynamic components such as flange couplings, turbine runners or dynamically loaded foundations:
PM Multi-Jackbolt Pretensioners (MJP)
in conjunction with
Conical Bolt and Conical Split Sleeve
We are happy to support you with the installation of your bolting solution or also with maintenance work.
Of course, we also offer competent support for Ex P&S products and installations.
PLOKE Multi-Jackbolt Pretensioners (MJP) are used for large bolted connections in all areas of industry. Where our standard series do not provide an optimal solution, we develop customized special designs. Benefit from over 30 years of know-how – put your trust in the original: PLOKE Multi-Jackbolt Pretensioners guarantee the best bolting solutions.
Multi-Jackbolt Pretensioners are used e.g. in general mechanical engineering, shipbuilding, heavy mechanical engineering, in power stations, in the chemical industry and the steel industry and are used on couplings, slewing rings, foundations, presses, part joints and much more.
Larger diameters (> M160), special thread geometries, special materials, extended temperature ranges or other application-specific designs.
We are an experienced Swiss engineering company with a focus on globally unique bolting solutions based on the MJP principle (mechanical Multi-Jackbolt Pretensioner) for absorbing the greatest forces.
With regard to quality and product safety, we leave nothing to chance – we build our products according to the highest quality requirements and can offer acceptances, tests, verifications and certificates of all kinds.
