Lifting clamp/tongs are indispensable load-handling devices when components, natural stones, or concrete segments need to be securely gripped, repositioned, and placed in an orderly manner. In combination with tools such as concrete demolition shears or hydraulic splitters, they enable structured workflows in concrete demolition and special deconstruction, in building gutting and cutting, in rock breakout and tunnel construction, as well as in natural stone extraction. While hydraulic cutting and splitting tools separate, lifting clamp/tongs take over the controlled transport and positional correction of the released parts—precisely, repeatably, and with a high safety standard.
Definition: What is meant by lifting clamp/tongs
A lifting clamp/tongs is a mechanical load-handling device that grips and lifts components via frictional or positive locking. The actuation is usually purely mechanical through scissor or parallelogram kinematics; the clamping force arises from the self-weight of the load and the geometry of the clamp. Lifting clamp/tongs are attached to crane hooks, hoists, or carrier machines and serve to lift concrete slabs, block stones, curbstones, rock boulders, or segmented components. Depending on the design, they grip horizontally or vertically, via friction linings or toothed grippers, and feature defined load capacities and gripping ranges.
Design and operating principle of a lifting clamp/tongs
Typical lifting clamp/tongs consist of a boom with suspension point, a kinematic mechanism (scissor or parallel guide), and two gripping jaws with linings or teeth. When lifting, the load pull angle generates a self-reinforcing clamping effect. Spring packs keep the clamp open when positioning or provide gentle pre-tensioning.
Key components
- Suspension: Eye or shackle for uptake by crane hook or coupling systems.
- Kinematics: Scissor arms or parallelogram for an even, parallel closing stroke.
- Grip surfaces: rubberized, ribbed, or toothed—matched to concrete, natural stone, or reinforced concrete.
- Adjustment mechanisms: index, pin, or spindle to adapt the gripping range.
- Retention systems: spring mechanism or latch for handling without crush hazard.
Types and gripping principles
Lifting clamp/tongs differ by gripping direction, contact type, and design. The correct choice depends on the material, geometry, and surface of the load.
Gripping direction
- Horizontal grippers (e.g., slab or block tongs) for transporting components in a horizontal position.
- Vertical grippers (e.g., stone tongs) for upright placement and rotations during the lift.
Contact and force engagement
- Frictional grippers with high-friction linings for sensitive surfaces such as fair-faced concrete or sawn natural stone.
- Positive-locking grippers with teeth or contours for rough rock, broken concrete, or irregular edges.
Kinematics
- Scissor tongs with fast, force-amplifying closing behavior.
- Parallel grippers for uniform pressure distribution on slabs and blocks.
Applications in combination with cutting and splitting technology
Lifting clamp/tongs demonstrate their value especially where components are deliberately detached and must then be safely rehandled. In many workflows they are used directly after concrete demolition shears or hydraulic splitters to remove separated segments from the work area, to sort them, or to stage them in the correct orientation.
Concrete demolition and special demolition
- After separating wall or slab segments with concrete demolition shears, the lifting clamp/tongs takes over controlled removal, prevents edge spalling, and enables low-vibration placement.
- For massive components, hydraulic splitters are used first; the lifting clamp/tongs then transports the resulting blocks.
Building gutting and cutting
- In interior areas, the lifting clamp/tongs assists with offset lifting of opening segments after cutting and with material-specific placement.
Rock breakout and tunnel construction
- After loosening with splitting cylinders, irregular blocks can be safely rehandled using positive-locking grip surfaces.
Natural stone extraction
- When handling raw blocks or calibrated slabs, the lifting clamp/tongs provides controlled gripping geometry to protect edges and maintain dimensional accuracy.
Special applications
- In areas with restricted access or sensitive environments, precast parts can be placed with low vibration, without requiring additional drilled or set points.
Selection criteria and sizing
The fit between load and clamp determines safety, efficiency, and surface protection. The following points should be checked before starting work:
- Load capacity: Rated load of the clamp ≥ maximum load incl. tolerances and any adhesion of residual material.
- Gripping range: Minimum and maximum openings must match the material thickness and tolerance.
- Surface compatibility: Choose linings (rubber, ribbed, toothed) according to material and visual requirements.
- Component geometry: Consider existing edges, webs, or embedded parts; plan sufficient bearing width.
- Center of gravity: Choose suspension so that the load hangs stably; rotators facilitate alignment.
- Ambient conditions: Moisture, mud, dust, or frost can reduce friction—allow safety margins if necessary.
Typical workflows with concrete demolition shears and hydraulic splitters
- Separation: Segment with concrete demolition shears along defined lines.
- Securing: Take the load, check pull angle, trial lift with lifting clamp/tongs.
- Transport: Move smoothly, avoid oscillations, maintain line of sight.
- Placement: Prepare dunnage, set down without stress, relieve and release the gripper.
- Splitting: Low-compaction demolition using hydraulic splitters.
- Grasp parts: Use positive-locking grip surfaces, consider irregular contours.
- Sorting: Place material types separately, prepare subsequent processing steps.
Occupational safety and organizational measures
Safe lifting operations require coordinated technology and clear procedures. The following notes are general and do not replace project-specific planning:
- Prepare a hazard assessment; define responsibilities, signals, and exclusion zones.
- Use only trained personnel; provide instruction on the clamp type and carrier machine.
- Before every lift: visual inspection of the clamp, slings, and suspension; verify load capacity and gripping range.
- No persons under suspended loads; smooth movements without jerks, limit pendulum motion.
- Consider weather: wet or icy contact surfaces reduce friction—choose other linings or procedures if necessary.
- Perform documented inspections at defined intervals; keep markings legible.
Carrier machines and slinging gear
Lifting clamp/tongs are used on cranes, excavators, or hoists. A suitable suspension and the correct choice of slinging gear are decisive.
Suspension
- Direct eye uptake or shackle; on excavators often with rotary motor/rotator for fine angle adjustment.
- Provide sufficient headroom to safely overtravel and rotate components.
Slinging gear
- Chains or round slings of suitable grade; consider sling angle and resulting additional forces.
- Short, symmetrical sling lengths promote smooth load travel.
Operation: best practices from the field
- Keep grip surfaces clean; adhesions reduce friction and increase slip risk.
- Mark bearing points to repeat center of gravity and grip line.
- Trial lift at low height; observe grip pressure during set-down movement.
- Pad sensitive edges with protection strips; avoid spalling.
- For varying material thicknesses, readjust the gripping range and document it.
Maintenance, inspection, and documentation
Regular care ensures the function of the clamping mechanism and the accuracy of the load ratings.
- Daily visual inspection: cracks, deformations, loose pins/bolts, condition of linings.
- Lubrication points as per instructions; prefer dry, low-dust lubrication.
- Monitor wear dimension of grip surfaces; replace in good time.
- Document periodic inspections by competent persons at defined intervals.
Distinction: lifting clamp/tongs, concrete demolition shears, and hydraulic splitters
Lifting clamp/tongs are used for lifting and repositioning. Concrete demolition shears separate or downsize components through compressive and cutting action; hydraulic splitters create controlled cracks and blocks through splitting force. In practice, the tools are combined: first separate or split, then guide and place the segments safely with the lifting clamp/tongs. This creates low-vibration, controlled process chains that take into account structural stability, noise control, and dust suppression.
Avoid common sources of error
- Undersized clamps or incorrect gripping range: leads to slippage or edge breakage.
- Unsuitable grip linings for the surface: visible damage or insufficient clamping.
- No trial lift and unclear center of gravity: load tipping.
- Excessive sling angles: additional transverse forces, uneven pressure.
- Dirty, wet, or icy contact surfaces: reduced friction coefficient.
Planning notes for deconstruction and extraction projects
For smooth workflows, it is advisable to plan lifting clamp/tongs already during method development: component sizes, cut or split lines, transport routes, and placement points should be coordinated. Especially in combination with concrete demolition shears and hydraulic splitters, work sequences can be structured so that separation, lifting, sorting, and further processing proceed without retooling or unnecessary additional grapples.