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Load pins, also known as force measuring pins or load measuring axles, measure forces directly in the force flow without changing the underlying mechanical design. They replace existing axles, hinge pins or bolted connections and turn a passive machine element into a sensor.
Whether lifting equipment, special machinery, offshore or agricultural engineering: we manufacture the load pin to suit the geometry and the ambient conditions of your application. From a few kilonewtons up to several hundred tonnes.
up to SIL 3 / PL e
redundant, with two independent strain gauge bridges
up to IP68 / IP69K
hermetically welded for underwater use and high-pressure cleaning
up to 250 °C
temperature compensation in special design
8 weeks
typical delivery time from drawing approval
Standard pin or custom-made
This question comes first, and the answer decides price and delivery time.
If in doubt, send us the drawing of your existing pin. We will tell you at short notice whether a standard item fits or an adaptation is needed.
Seamless integration without design changes
The biggest advantage is the design itself. You send us the dimensions of the existing pin, i.e. length, diameter and position of the locking element, and we manufacture the load pin as an exact geometric replica. Bearing, pulley and locking stay unchanged, the assembly keeps its function, and you gain a reliable measured value.
This makes load pins particularly attractive for retrofits: no redesign, no additional installation space and no intervention in the force flow.
From our production
A selection of custom load pins, designed, manufactured, gauged and calibrated in-house.
How a load pin measures
A load pin does not measure the load itself but the shear deformation it causes in the pin. For this, the diameter of the pin is reduced at the transitions between the supports and the load-bearing centre section. The strain concentrates in these deformation zones, and that is exactly where the strain gauges sit, wired as 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 load introduction are part of the design. Second, the pin must sit in the force flow secured against rotation so that the measuring direction is correct. We take both into account in the design as soon as we know the installation situation.
The full bridge compensates for temperature effects; the pins are designed to be vibration- and shock-resistant and keep their accuracy over the entire temperature range.
Designs at a glance
The design follows from the installation point and from what is to be measured. We make these versions:
Double shear
the normal case: the pin sits in a clevis with two supports and the load acts in the middle, see standard design
Single shear
supported on one side only, the load acts overhung next to it; for installation points without a clevis, the additional bending moment is part of the design
Biaxial
two measuring bridges across each other capture magnitude and direction of the load when the direction of force wanders, see application report 220 kN
Redundant
two independent measuring bridges and separate signal paths for safety-related applications, see SIL / PL
Shackle pins
the pin of a load shackle becomes the sensor, also with battery and radio, see wireless load shackle 250 kN
ATEX
versions for potentially explosive atmospheres with ATEX, IECEx or CSA approval, see ATEX
Signals, interfaces and measuring electronics
Depending on the system architecture and the degree of automation, we supply the full range of signal outputs, from passive sensors for an external control cabinet to fully integrated digital solutions.
Passive, without amplifier
mV/V output for external measuring amplifiers on the DIN rail
Analog, integrated
4-20 mA (2-wire/3-wire), 0-10 V, -10 to +10 V
Digital, integrated
CANopen, CANopen Safety, PROFINET, PROFIsafe or IO-Link
If space in the joint is tight, we use remote electronics. If the pin offers enough room, we integrate the signal amplification directly into the housing. This minimises interference and simplifies wiring, because no sensitive mV/V signal has to be routed over long distances.
Standard technical data
| Feature | Value |
|---|---|
| Temperature compensation | -40 to +80 °C |
| Limit load | 150 % of rated load |
| Breaking load | 300 % of rated load |
| EMC immunity | 200 V/m |
| Zero drift | no recalibration required |
| Design | fatigue-resistant, for tension and compression |
| Safety rating | up to SIL 3 / PL e |
| Protection class | up to IP68/IP69K |
| Material | high-strength stainless steel (usually 17-4PH) |
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 custom cables and connectors.
Calibration in a replicated installation situation
A load measuring axle measures differently depending on bearing width, gap and point of load introduction. A calibration certificate produced on a generic test rig therefore says little about the accuracy in your machine.
For calibration we replicate your installation situation and calibrate the pin in it, including a test report. This gives you a characteristic value that matches your design rather than an idealised 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 in heavy machinery, 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 measuring amplifiers
Separate signal paths
separate internal wiring and separate connection points reduce common-cause failures
Diagnostic capability
the architecture allows the higher-level safety controller to check both signals for plausibility at all times
We back the design with FEM calculation, laboratory and field tests. The characteristic values we provide for the safety assessment are based on conservative assumptions and can be used in different architectures. More on the functional safety page.
Mechanical configurations and special equipment
No two installation 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 steelworks, foundries and furnace technology, see high temperature
Robust materials
high-strength stainless steel as standard against corrosion and harsh environments
Protection classes up to IP68 and IP69K
IP65 or IP67 is usually sufficient for industrial use; for underwater use or high-pressure cleaning we make hermetically welded housings
Electrical connection
fixed cable, axial or radial depending on the installation, or industrial connectors such as M12
Lubrication bores
internal lubrication channels and grease nipples to grease moving bearing points through the pin
Anti-rotation locking
milled retaining plates, grooves or flats keep the pin exactly in the measuring direction
Biaxial design
one pin measures the force in two directions, see the application report biaxial load pin for 220 kN
Mechanical manufacturing is done in-house, as are strain gauge application and CNC machining. Design, manufacturing, application and calibration are thus all in one hand.
Applications
Because the rated load can be scaled freely, load pins are used across industries:
Cranes and lifting
overload protection on deflection pulleys, rope anchor points and winches
Construction machinery
load moment limitation on excavators, wheel loaders and booms
Offshore and marine
winch control, chain stoppers and mooring monitoring
Agricultural engineering
draught force measurement on tractors and implements
Stage technology
rope force monitoring in theatre and event rigging
Rail and automotive
force measurement on chassis and test rigs
Guide: installation and operation
Whether a load pin measures accurately and lasts long is decided to a large extent during installation and by the conditions in operation. Two articles sum up what matters.
When a pin is not the right solution
A load pin requires a bolted connection in the force flow that can be replaced. If there is none, other designs fit better: tension links for anchor points and tension members, rope tension load cells for measuring on running or stationary ropes without cutting them, and our other load cells and force transducers for installations with defined load introduction.
If you are unsure which design fits, describe the installation site to us. We will tell you frankly if another solution is cheaper or more accurate.
Delivery time
For custom load pins the typical delivery time is 8 weeks from drawing approval. For urgent projects we usually find a way, please ask us.
What we need for a quotation
With this information you get a reliable quotation instead of a follow-up question:
- Rated load and whether tension, compression or both act
- Drawing or dimensions of the existing pin: diameter, overall length, bearing width, position and type of locking
- Installation situation: where the load acts, how wide the supports are, whether anti-rotation locking is possible
- Environment: temperature range, required protection class, outdoor use, hazardous area
- Signal: passive mV/V, analog, or digital via CANopen, PROFINET or IO-Link
- Safety requirement: whether SIL or PL is required, and at which level
- Cable outlet: axial or radial, length to the evaluation electronics
- Quantity and required date
An assembly drawing or a photo of the installation site is often enough for a first assessment. If something is missing, send what you have; we will clarify the rest together.
Frequently asked questions about load pins
How does a load pin work?
It measures the shear deformation the load causes in the pin. Strain gauges sit in machined deformation zones as a full bridge whose signal changes in proportion to the force.
Can I simply replace an existing pin?
Yes. We manufacture the load pin as a geometric replica of your existing pin, so bearing, pulley and locking stay unchanged and no redesign is needed.
What is the difference between a force measuring pin and a load pin?
They are two names for the same component, as are load measuring axle and measuring pin. In practice the only distinction is between standard design and custom manufacturing.
Which safety levels are possible?
With a 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 design and installation. Because we calibrate in a replicated installation situation, you get a characteristic value that applies to your design, with a documented test report.
Do you have a specific measuring task? Whether it is a replacement for a simple standard pin or a redundant system with a digital interface for special machinery: send us your drawing via the quotation form and our engineers will come back to you with a proposal.
Order the standard design directly
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