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Double Actuator

Hydraulic grips Download
Material
  • Metals
  • Wood
Test load
  • 50 kN - 250 kN
Specimen shape
  • Flat specimens
  • Round specimens
  • Short clamping lengths
Type of test
  • Tensile
  • Compression
  • Alternating load

Symmetrical and asymmetrical gripping

Double-actuator hydraulic grips always close symmetrically with respect to the tensile axis. This means the specimen is gripped in a precise axial position, thereby eliminating the need for thickness adjustment.

Testing of sintered metal specimens

The patented hydraulic grip is also ideally suited for short clamping lengths.

Advantages & features

Advantages & features

Advantages
Operating principle
Function description, short clamping lengths
Double-sided actuators
Single-sided and double-sided closing specimen grips
T-slotted system

Advantages

  • The constant gripping force allows for repeatable test results.
  • Reliable testing results are guaranteed with the optimal interaction between the hydraulic power pack, the electronics, and the testing software. The force-zero control prevents unwanted forces on the specimen during the gripping process.
  • Time is saved due to quick and easy adaptation of small specimen grips and test fixtures to large specimen grips via the T-slotted system. Precise alignment ensures reliable test results.
  • The symmetrically closing jaws save time required for adjusting to varying specimen thicknesses and ensure that the specimen is held exactly in the test axis.
  • Short specimens can also be gripped due to the special design of the specimen grip.
  • Fast and easy insertion of specimen due to the ergonomic and open design.
  • Accurate test results along with a high cycle rate that is made possible by central insertion of the sample with the aid of an easily adjustable centering stop.

Operating principle

The oil pressure is set at the hydraulic power pack according to the required closing pressure for the specimen grips. The control unit controls the closing and opening procedure separately for the top and bottom specimen grips.

Furthermore, the closing procedure is divided into a closing phase and gripping phase when a a universal hydraulic power pack is used. In the closing phase, the specimen is initially held on the upper end for safety reasons. During gripping, the full gripping force is applied. The force value is based on the expected tensile force.

Function description, short clamping lengths

It is not necessary to set the thickness. This is a big advantage, above all, for soft specimens or if specimen thickness changes.

Double-sided actuators

All hydraulic grips are equipped with double-sided actuators. This means the specimen grip opens hydraulically and not by means of spring return mechanism. The closing and opening pressure can be adjusted.

In contrast to single-acting actuators that open by means of a spring return mechanism, double-sided actuators ensure that the specimen grips always open safely . This also applies if the specimen is crooked or jammed. Additionally, the full opening stroke is not necessary because the opening procedure can be interrupted at any point using the Stop button. The opening stroke can be adjusted according to thickness. Especially with thin specimens, the test time is reduced and the risk of pinching parts of the body is minimized.

Single-sided and double-sided closing specimen grips

Single-actuator hydraulic grips can be used for the symmetrical and asymmetrical gripping of specimens (for example, for shear tests). The thickness of the specimen is set by means of screw unit.

The single-actuator hydraulic grips are also available with a tandem cylinder to enable uniform force application to the specimen (especially suitable for tests on fabrics, textiles and geotextiles).

Double-actuator hydraulic grips always close symmetrically with respect to the tensile axis. This means the specimen is gripped in a precise axial position, thereby eliminating the need for thickness adjustment.

T-slotted system

The T-slotted system makes it possible to accommodate small load cells, specimen grips, test tools, and fixtures quickly, without having to dismantle the specimen grips.

T-slots are integrated in the gripping area of the specimen grip. These serve as mounts for the T-slotted mounting. The T-slotted mounting is clamped there. Other fixtures can now be mounted, saving time needed to mount other tools and fixtures.

Properties according to force range

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Downloads

Name Type Size Download
  • Product information: Hydraulic grips, Fmax 50 kN PDF 146 KB
  • Product information: Hydraulic grips, Fmax 100 kN / 250 kN PDF 691 KB
  • Product information: Hydraulic grips for short clamping lengths, Fmax 50 kN / 70 kN PDF 369 KB
  • Product information: Hydraulic grips for short clamping lengths, Fmax 150 kN / 250 kN PDF 330 KB
  • Product information: Hydraulic grips up to 2500 kN PDF 280 KB
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