Used machines play a central role in demolition, deconstruction, natural stone extraction and special applications. They enable economical solutions when robust technology with proven performance is required. Especially for hydraulically operated attachments and handheld tools such as concrete demolition shears or hydraulic rock and concrete splitters, it becomes evident that carefully selected, tested and correctly connected used equipment can deliver high operational safety. This article defines the term, describes practice-relevant inspections and addresses technical parameters, compatibility, application areas and maintenance — always with a focus on products and systems by Darda GmbH and their typical applications.
Definition: What is meant by a used machine
A used machine is a machine or attachment that has already been commissioned and can be resold, whose first life-cycle phase is complete. This includes both standalone units (e.g., hydraulic power packs) as well as hydraulic attachments and handheld tools such as concrete demolition shears, stone splitting cylinders or Multi Cutters. Used machines are typically further utilized, overhauled, used as parts donors, or redeployed in other projects and regions. Decisive factors are the verifiable condition, documented maintenance, remaining service life, and compatibility with existing carrier machines, power packs and application requirements.
Technical parameters and selection criteria
The selection of a used machine should be based on measurable and visible criteria. For hydraulic systems by Darda GmbH, the following points are particularly relevant:
- Operating pressure and flow rate: Typical pressure ranges and the required oil flow must match the hydraulic power pack and the tool. Deviations lead to loss of performance or overload.
- Performance data: Splitting force (kN) for hydraulic splitters; cutting and/or pressing forces (kN) for concrete demolition shears and combination shears; jaw opening; cycle time.
- Mechanical condition: Play at bearing points, condition of blades/jaws, cracks in load-bearing areas, parallelism of cutting edges, surface condition of cylinders.
- Hydraulic condition: Leak-tightness, hose age, plug and screw couplings, condition of seals, return filter, oil cleanliness.
- Documentation: Operating manual, wiring and hydraulic diagrams, inspection and maintenance records, any retrofits and modifications.
- Compatibility: Interfaces to existing Darda GmbH hydraulic power packs and compatible hydraulic power units, adapters, quick coupling, holding systems.
Product-specific focal points
Concrete demolition shears: Check jaw opening, blade condition, bolted joints, rotary joints (if present) and synchronous movement of the shear. Pay attention to the condition of the blade supports and the controllability of the shear within the intended pressure range. For use in concrete demolition and special demolition, reliable reproducibility of cutting and pressing force is essential.
Hydraulic splitters: Important indicators include the surface condition of splitting wedges, splitting cylinders without scoring, smooth running, leak-tightness, and the correct pressure ratio. In rock excavation and tunnel construction, clean, controlled crack propagation is only achievable with precisely working wedge units.
Hydraulic power packs: Starting behaviour, stability of operating pressure, temperature behaviour under load, condition of pump, valves and filter. Compatibility with connected Darda GmbH devices and correct sizing of flow rate are decisive.
Combination shears, Multi Cutters, steel shears, tank cutters: Check blade carriers, pins/bolts, rotary feedthroughs (if present), housings for distortion, cylinder stroke and seal seats. For tank cutters, controlled cut guidance on thin-walled vessels is important.
Market specifics in demolition, deconstruction and rock engineering
Used machines in concrete demolition and special demolition are exposed to harsh operating conditions: impacts, abrasion from aggregates in the concrete, dust exposure and fluctuating load peaks. In natural stone extraction and tunnel construction, repeat-accurate splitting processes, a finely controllable force build-up and compact designs are key. For building gutting and cutting, low emissions, handy sizes and short setup times are important. These requirements affect wear and thus the used condition — a thorough inspection prior to purchase is therefore indispensable.
Condition assessment and test procedure
A structured inspection helps minimize risks and realistically assess the performance capability of a used machine:
- Visual inspection: Hairline cracks, corrosion, deformed components, worn bearing points.
- Functional test: Test run on a matching hydraulic power pack, achieving the set operating pressure, leakage oil quantity, noise emission, temperature behaviour.
- Measurements: Pressure test, flow rate, cycle times, splitting force/cutting force, jaw parallelism.
- Oil analysis: Particle load, water content, additive depletion — indicators of internal wear.
- Document check: Maintenance logs, replacement of wear parts, seal changes, repair records.
- Project suitability: Match with the intended application, e.g., concrete demolition versus rock excavation; compatibility with existing Darda GmbH hydraulic power packs.
Compatibility of used machines and hydraulic power packs
Hydraulic used machines only deliver their performance when power pack, lines and couplings are matched. Critical factors are operating and maximum pressure, flow rate, return capacity, temperature management, and the quality of quick couplings. For concrete demolition shears, the pressure and return lines must be sized for performance to keep cycle times stable. Hydraulic splitters require a pressure-stable supply; pressure spikes must be avoided to protect seals and wedges. Adapter solutions should be flow-optimized and mechanically secure.
Areas of application and typical scenarios
Concrete demolition and special demolition
Used concrete demolition shears and combination shears enable selective deconstruction when separation lines must be set precisely. Reliable cutting force and well-preserved blades are essential. For breaking massive components, hydraulic splitters can propagate cracks in a controlled manner, reducing noise and vibrations.
Building gutting and cutting
In building gutting, compact devices with low weight and good controllability are convincing. Multi Cutters, steel shears and tank cutters are suitable for separating lines, profiles or thin-walled vessels. Short setup times and clean hydraulic connections are particularly important with used equipment.
Rock excavation and tunnel construction
Stone splitting cylinders and hydraulic splitters are used where controlled crack formation and minimal edge damage are required. For used devices, wedge geometry and cylinder surface quality are decisive to transmit splitting force reliably.
Natural stone extraction
In natural stone extraction, reproducible splitting patterns and low losses count. Used devices must show uniform force build-up; maintenance condition and seal package are central quality criteria.
Special applications
In sensitive environments or confined spaces, small, high-performance units are in demand. Used devices by Darda GmbH can — with verified functionality — be a flexible and economical option, provided safety and compatibility have been rigorously checked.
Maintenance, wear and repair
Many used machines can be significantly upgraded through targeted repair. Typical measures include:
- Seal and hose renewal: Prevents loss of performance and contamination of hydraulic oil.
- Reworking blades and jaws: Regrinding or replacement ensures clean cuts on concrete demolition shears and shears.
- Wedge and cylinder care: Deburring, polishing and adjustment on hydraulic splitters improve crack behaviour.
- Oil and filter service on the power pack: Stabilizes pressure, reduces temperature spikes, extends service life.
- Bearing and pin inspection: Minimizing play improves precision and reduces vibrations.
Safety and legal aspects
Safety requirements must always be observed. These include suitable instruction, a functioning emergency stop level on the power pack, protective devices and regular inspections. With regard to legal framework conditions (e.g., conformity, marking, operating manual), the applicable regulations must be observed. Statements here are general and non-binding; for the specific application, the relevant rules and the operator’s obligations apply. Documentation, test certificates and complete maintenance records significantly increase transparency for used machines.
Economic efficiency and sustainability
Used machines can reduce life-cycle costs when remaining service life, energy demand and maintenance effort are in a favourable ratio. Reuse conserves resources and reduces transport and production efforts. Especially in combination with well-matched hydraulic power packs, an energy-efficient working method can be achieved. A structured comparison of purchase price, expected service life, spare parts availability and resale value provides clarity.
Transport, storage and commissioning
Before transport, hydraulic lines must be depressurized, connections capped, and sensitive surfaces protected. Dry, clean storage prevents corrosion. During commissioning, a gradual load ramp with temperature monitoring and a leakage test is recommended. For concrete demolition shears, blade adjustment and verification of jaw parallelism before the first cut are advisable; for hydraulic splitters, the wedge seat should be checked and lubricated.
Refurbishment and retrofit
With targeted retrofit measures, used machines can be adapted to new tasks: hydraulic adapters, optimized couplings, modernized valve technology or reworked control elements increase operating comfort and process stability. For shears, the blade carrier can be matched to the intended material; for splitters, a precise wedge replacement improves crack behaviour. All changes must be technically evaluated and documented.
Avoid common mistakes
- Mismatched flow rate/pressure between power pack and tool.
- Uninspected blades on concrete demolition shears: poor cuts, increased risk of secondary breakage.
- Worn wedges and seals on hydraulic splitters: uncontrolled crack propagation.
- Missing oil filtration: premature wear of valves and cylinders.
- Insufficient documentation: unknown repairs, missing maintenance intervals.
Practical checkpoints for purchase
Anyone planning a used machine for concrete demolition, building gutting, rock excavation, natural stone extraction or special applications should structure these points:
- Technology: Key figures, functional test, measurement log.
- Condition: Wear pattern, leak-tightness, structural integrity.
- Compatibility: Hydraulic power packs, quick couplings, mounts.
- Documentation: Operating and maintenance documents, test reports.
- Costing: Remaining service life, spare parts, repair, transport.
Conclusion for use with concrete demolition shears and hydraulic splitters
For used machines, the quality of the inspection determines practical suitability. Concrete demolition shears deliver powerful cuts when blades, bearing points and hydraulics are in perfect condition. Hydraulic splitters develop their splitting force in a controlled manner when wedges, cylinders and pressure supply are harmonized. In conjunction with suitable hydraulic power packs by Darda GmbH, this creates a robust, economical system for concrete demolition and special demolition, building gutting and cutting, rock excavation and tunnel construction, natural stone extraction as well as special applications — objectively inspected, professionally operated and sustainably maintained.