Load Pins and Load Measuring Axles

Load pins, also known as force measurement pins or shear pins, measure forces directly in the force flow without the need to modify the underlying mechanical design. They replace existing axles, hinge pins, or bolted connections, transforming a passive machine element into a sensor.

Whether for lifting technology, special machine construction, offshore applications, or agricultural engineering: we manufacture load pins to match the geometry and environmental conditions of your application. From a few kilonewtons up to several hundred tons.

Load Pins and Force Measurement Pins: Standard or Custom-Made

This question is at the beginning, and the answer determines the price and delivery time.

Standard Version. If your design is still open or the mounting can be adapted to the pin, a standard load pin is the quicker and more cost-effective solution. These pins are available from stock, with prices and datasheets online. Please see our standard load pins for more information.

Customized Production. As soon as the pin needs to fit into an existing design, meaning length, diameter, bearing width, and securing position are predefined, we manufacture it as a geometric replica of your previous pin. The same applies to special requirements for nominal load, protection class, temperature, redundancy, or certification.

If in doubt, send us the drawing of your existing pin. We will tell you quickly whether a standard item fits or if a customization is necessary.

Seamless Integration Without Design Changes

The biggest advantage lies in the design. You provide the dimensions of the existing pin, i.e., length, diameter, and position of the securing element, and we manufacture the measuring pin as an exact geometric replica. Bearings, rollers, and securing elements remain unchanged, the function of the assembly is maintained, and you additionally receive a reliable measured value.

This makes load pins and force measurement pins particularly attractive for retrofitting: you don't need a redesign, no additional installation space, and no intervention in the force flow.

How a Load Pin Measures

A load pin does not measure the load itself, but rather the shear deformation it produces in the pin. For this purpose, the pin's diameter is reduced at the transitions between the supports and the load-bearing central part. Strain concentrates in these deformation zones, and this is precisely where the strain gauges are located, wired into a Wheatstone full bridge.

This principle has two practical consequences. First, the pin measures the shear force between the supports, which is why bearing width and the point of force application are included in the design. Second, the pin must be torsion-resistant in the force flow to ensure the correct measuring direction. We take both into account during construction, once the installation situation is known to us.

The full bridge compensates for temperature influences, the pins are designed to be vibration- and shock-resistant, and maintain their accuracy over the entire temperature range.

Signals, Interfaces, and Measurement Electronics for Load Pins

Depending on the system architecture and degree of automation, we supply the entire spectrum of signal outputs, from passive sensors for external control cabinets to fully integrated digital solutions.

If space in the joint is tight, we rely on remote electronics. If the pin offers enough space, we integrate the signal amplification directly into the housing. This minimizes interference and simplifies wiring, as no sensitive mV/V signal has to be routed over longer distances.

Technical Specifications in Standard

Optionally available: increased limit and breaking load, for example 300% and 500%, temperature compensation up to 250°C, redundant design, protection class IP69K, remote amplifiers, as well as customized cables and connectors.

Calibration in a Simulated Installation Situation

A force measurement axle measures differently depending on the bearing width, gap dimension, and point of force application. A calibration certificate created on a generic test setup therefore says little about the accuracy in your machine.

We simulate your installation situation for calibration and calibrate the pin within it, including a test report. This gives you a characteristic value that matches your design and not an idealized mounting. On request, we also calibrate according to ISO 17025 in our own laboratory.

Functional Safety: Redundancy for Critical Applications

In crane and lifting technology and heavy machinery construction, standards such as EN 61508, EN 62061, and ISO 13849 require fail-safe systems. For these applications, we design redundant load pins that can meet requirements up to SIL 1 to 3 and PL c to e.

• True Redundancy: two completely independent strain gauge bridges and measurement amplifiers
• Separate Signal Paths: separate internal wiring and separate connection points reduce failures due to common causes
• Diagnostic Capability: the architecture allows for permanent plausibility checking of both signals by the higher-level safety controller

We accompany the design with FEM calculations, laboratory, and field tests. The characteristic values we provide for safety considerations are based on conservative assumptions and can be used in different architectures.

Mechanical Configurations and Special Equipment

No two application sites are alike, so we adapt the mechanical properties to the environment.

• ATEX, IECEx, and CSA: Certifications for use in potentially explosive atmospheres, for example in the oil and gas industry, chemical plants, or silos
• High Temperature up to 250°C: specially designed versions for steel mills, foundries, and furnace technology
• Robust Materials: high-strength stainless steel as standard against corrosion and harsh environments
• Protection Classes up to IP68 and IP69K: for industrial applications, IP65 or IP67 is usually sufficient; for underwater use or high-pressure cleaning, we manufacture hermetically sealed housings
• Electrical Connection: fixed cable axial or radial, depending on the installation situation, or industrial-grade connectors such as M12
• Lubrication Holes: internal lubrication channels and grease nipples for lubricating moving bearing points through the pin
• Anti-Rotation Devices: milled retaining plates, grooves, or flats keep the pin exactly in the measuring direction

Mechanical manufacturing is done in-house, as is strain gauge application and CNC machining. Design, manufacturing, application, and calibration are thus all under one roof.

Applications for Load Pins and Force Measurement Pins

Due to the free scalability of nominal loads, load pins are used across industries:

• Crane and Lifting Technology: overload protection on guide pulleys, rope ends, and winches
• Construction Machinery: load moment limitation on excavators, wheel loaders, and booms
• Offshore and Marine: winch control, chain stoppers, and mooring monitoring
• Agricultural Technology: traction force measurement on tractors and implements
• Stage Technology: cable force monitoring in theater and event riggings
• Rail and Automotive: force measurement on chassis and test equipment

A concrete project example can be found in our application report on load pins in theater technology.

When a Pin is Not the Right Solution

A load pin requires that there is a bolted connection in the force flow that can be replaced. If there isn't one, there are more suitable designs: tension links for attachment points and tension members, cable tension load cells for measuring on running or stationary ropes without disconnection, and the other load cells and force transducers for installation situations with defined force application.

If you are unsure which design is suitable, describe the installation site to us. We will tell you frankly if another solution is more cost-effective or more accurate.

Delivery Time

For customized load pins, the typical delivery time is 8 weeks from drawing approval. For urgent projects, we usually find a way; please contact us about this.

What We Need for a Quote

With this information, you will receive a reliable quote instead of a query:

• Nominal load and whether tension, compression, or both apply
• Drawing or dimensions of the existing pin: diameter, overall length, bearing width, position and type of securing element
• Installation situation: where does the load act, how wide are the supports, is an anti-rotation device possible
• Environment: temperature range, required protection class, outdoor use, hazardous area
• Signal: mV/V passive, analog, or digital via CANopen, PROFINET, or IO-Link
• Safety requirement: whether SIL or PL is required, and at what level
• Cable outlet: axial or radial, length to the evaluation electronics
• Quantity and desired date
  

A mounting drawing or a photo of the installation site is often sufficient for an initial assessment. If you lack any of this, send what you have; we will clarify the rest in a conversation.

FAQ - Frequently Asked Questions about Load Pins and Force Measurement Pins

How does a load pin work? It measures the shear deformation created by the load in the pin. Strain gauges are located in milled deformation zones as a full bridge, whose signal changes proportionally to the force.

Can I simply replace an existing pin? Yes. We manufacture the measuring pin as a geometric replica of your previous pin, so that bearings, rollers, and securing elements remain unchanged, and no redesign is necessary.

What is the difference between a force measurement pin and a load pin? These are two terms for the same component, as are force measurement axle, measuring pin, or load pin. In practice, the only distinction is between standard and customized production.

Which safety levels are possible? Through redundant design with two independent strain gauge bridges and separate signal paths, applications up to SIL 3 according to EN 61508 and PL e according to ISO 13849 are possible.

How accurate is a load pin? That depends on the design and installation situation. Because we calibrate in a simulated installation situation, you receive a characteristic value that applies to your design, with a documented test report.

Do you have a specific measurement task? Whether it's a replacement for a simple standard pin or a redundant system with a digital interface for special machinery construction: send us your drawing, and our engineers will get back to you with a proposal.