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Grips & Fixtures

Manually Operated Grips / Fixtures

Eccentric Roller Grips –
TJ 10

About the Grip

Eccentric Roller Grip is a general-purpose grip for flat samples.

– This model is suitable for samples upto 25mm wide and 5mm thick.

– These are self-tightening grips primarily designed for the precision testing of elastomeric and other flexible materials exhibiting a large reduction in cross-section area under load.

– The sample is held between the body and the eccentrically mounted roller as the load increases the gripping action becomes self-tightening due to the cam action between the roller and the body.

– It has a crosshatched, serrated finish and clamps tightly against a horizontal back plain.

– The upper grip is counterbalanced so that the specimen can be aligned with the load cell to eliminate non-axial forces.

– They provide excellent testing accuracy, positive non-slip gripping action, and are quick and simple to use.

– There are two models of Roller grips and depending on the type, samples of 25 – 50 mm wide and 5-6mm thick can be accommodated.

– Thicker samples will fit but the load axis moves to far from the centre of the mounting hole, also the self-tightening action becomes less effective with thicker samples.

– Electro-less Nickel plated surface finish are used throughout to provide excellent corrosion and scratch protection.

Features
  • Fast action for rapid specimen insertion to increase testing throughput
  • Positive, non-slip gripping action for accurate results.
  • Self-aligning upper grip prevents off-axis loads for consistent test data
  • Ideal for testing elastomers, & flexible plastics.
  • Rugged design for minimum maintenance
  • Designed for use in ambient and non-ambient testing conditions.
Principle of Opearation
  1. The self-tightening grip uses a serrated eccentric roller-type clamping action.
  2. The one-lever, fast action reduces the time required to load specimens.
  3. Specimen insertion is extremely easy and the spring pressures of the roller bracket giving a positive non-slip action gripping force.
  4. This is sufficient to hold the material until a load is applied.
  5. The follow-up action of the roller while under test prevents the specimen from creeping out of the grip as the load increases.
Application
APPLICATIONS sheet materials, polymers and some rubbers.
Temperature Range

Application in Rubber testing where testing Temperature range can range from -40˚C to 200˚C

Wide Eccentric Roller Grip -
TJ 23

About the Grip

Wide Eccentric Roller Grip is a general-purpose grip for flat samples.

– This model is suitable for samples upto 5omm wide and 5-6mm thick. (can be customised to accommodate slightly thicker samples)

– These are self-tightening grips primarily designed for the precision testing of elastomeric and other flexible materials exhibiting a large reduction in cross-section area under load.

– The sample is held between the body and the eccentrically mounted roller as the load increases the gripping action becomes self-tightening due to the cam action between the roller and the body.

– It has a crosshatched, serrated finish and clamps tightly against a horizontal back plain.

– The upper grip is counterbalanced so that the specimen can be aligned with the load cell to eliminate non-axial forces.

– They provide excellent testing accuracy, positive non-slip gripping action, and are quick and simple to use.

– There are two models of Roller grips and depending on the type, samples of 25 – 50 mm wide and 5-6mm thick can be accommodated.

– Thicker samples will fit but the load axis moves to far from the centre of the mounting hole, also the self-tightening action becomes less effective with thicker samples.

– Electro-less Nickel plated surface finish are used throughout to provide excellent corrosion and scratch protection.

Features
  • Fast action for rapid specimen insertion to increase testing throughput
  • Positive, non-slip gripping action for accurate results.
  • Self-aligning upper grip prevents off-axis loads for consistent test data
  • Ideal for testing elastomers, & flexible plastics.
  • Rugged design for minimum maintenance
  • Designed for use in ambient and non-ambient testing conditions.
Principle of Operation
  1. The self-tightening grip uses a serrated eccentric roller-type clamping action.
  2. The one-lever, fast action reduces the time required to load specimens.
  3. Specimen insertion is extremely easy and the spring pressures of the roller bracket giving a positive non-slip action gripping force.
  4. This is sufficient to hold the material until a load is applied.
  5. The follow up action of the roller while under test prevents the specimen from creeping out of the grip as the load increases.
Application
APPLICATIONS sheet materials, polymers and some rubbers.
Temperature Range

Application in Rubber testing where testing Temperature range can range from -40˚C to 200˚C

Universal Parallel Wedge Grips-TJ 15

About Grip
  • Wedge grips are mainly designed for testing of metals, plastic dog-bone shape samples as well as wooden specimens with soft to mid-hard surfaces.
  • Wedge grips possess a solid body with interchangeable jaw inserts with a mechanism for opening and closing of the grip.
  • The wedge grips come with a pre-tensioned spring, which generates the pre-gripping force.
  • The main gripping force will be applied through the wedge action.
  • The gripping pressure adjusts itself using a moving wedge in a constant ratio to the tensile strength.

Description:

  • The manual wedge action grip is designed for easy specimen loading, alignment and positioning.
  • After initial face to specimen contact, gripping force will increase as the testing load increases.
  • Virtually no pre-load is seen during specimen clamping due to Dak’ s design of moving grip bodies.
  • This makes them particularly suitable for testing high strength materials, such as metals and composites, ensuring that the specimen slippage is eliminated.
  • There are two basic types of mechanical wedge grips.
  • Either the grip bodies move and the wedges remain stationary while being tightened on the specimen, or the wedges move as they tighten on the specimen and the bodies of the grips remain stationary.
Principle of Operation

The wedge action principle of these grips allows them to be tightened onto a specimen without altering the vertical position of the faces in relation to the specimen. This is accomplished by a design, which moves the grip body to close the faces. This feature makes it possible to pre-select the exact point at which the specimen will be held with consistent gage length and no compressive force applied which may cause specimen buckling.

A strong clamping force can be applied to materials that are difficult to hold through a high mechanical advantage achieved by the tightening mechanism. The grip faces are spring loaded against a shoe which is in a fixed position in respect to the testing frame holding mechanism, only a light initial gripping force needs to be applied to the specimen. As the grip is tightened, it’s frame is drawn up and the inclined sides push against the matching side of the faces which move laterally against the specimen. A shoe incorporated to the driving shaft prevents the faces from moving.

The open front design of the grip frames allows faces to be easily interchanged as well as easy specimen loading.
Because the faces are held in fixed position, there is no recoil, or loosening, when the specimen ruptures and if an extensometer is attached, it will remain in place.

Features
  • Gripping force is proportional to the tensile strength, and the grip will self-clamp itself as the load increases
  • Wedge grips are symmetrical and they close in the tensile axis direction
  • The high temperature resistance ( -70 up to 300°C) and low overall height of these grips makes them suitable for use in temperature chambers
  • Wedge grips are designed to be very simple and quick.
  • The long clamping length and excellent jaw guidance properties enable the area pressure on the specimens to be minimized.
Application
  • Type of Loading: tensile, static and tension cyclic tests.
  • Specimen Material:  Suitable for gripping high strength rigid material such as wires, plastics, metals, elastomers.
  • Specimen Types: flat, round.
Temperature Range
  • Max Specimen Width:
    Flat faces w=50mm
    Round range 4-8, 8-22, 22-32mm
  • Max Specimen Thickness:
    Flat faces t=15
  • Temperature Ranges:
    T1: RT to +60°C
    T2: RT to +300°C
    T3: – 70˚C to +300˚C

Circular Wedge Grip - TJ 135

About the Grip

– Heavy Duty grips for heavier loads.

– Load capacity from 20kN onwards.

– The self-tightening wedge design ensures that there is no slippage during testing.

– The interchangeable jaw faces allow for testing of a wide range of specimen geometries and types. 

– These grips offer quick and easy set-up with rapid clamping and unclamping action, resulting in increased productivity.

– Various types, sizes, and surfaces of jaw faces are available to meet the specific testing needs.

– Jaws / Faces: Width 30mm, Height: 35mm

– Opening Size 0 – 7mm

– Additional round faces are also available for circular samples  (higher sizes available on request).

– High and Low-temperature compliant models available as required.

Principle of Operation

– These grips utilize the wedge action principle to grip specimens without changing the vertical position of their faces.

– This is achieved by moving the grip body to close the faces, enabling the selection of the exact point at which the specimen will be held with consistent gauge length and no compressive force applied.

– This is particularly useful for preventing specimen buckling.

– The grips are also capable of applying a strong clamping force to difficult-to-hold materials, due to a high mechanical advantage achieved through the tightening mechanism.

– The grip faces are spring-loaded against a fixed shoe, which reduces the need for a high initial gripping force on the specimen.

Design & Operation

– The grip frames feature an open front design, which facilitates easy interchangeability of the faces and allows for simple loading of specimens.

– The fixed position of the faces ensures that there is no recoil or loosening when the specimen ruptures.

– Additionally, if an extensometer is attached to the grip, it will remain securely in place throughout the testing process.

– During the tightening of the grip, the frame is drawn upwards and the inclined sides apply pressure against the matching side of the faces, causing them to move laterally and grip the specimen.

– A shoe is included on the driving shaft to prevent the faces from retracting during the gripping process.

Applications

Wedge grips are used for:

– Easy Sample placement.

– Ensures Sample positioning.

– Easy and accurate alignment.

Samples like Heavy Rigid plastics, Metals, Aluminum strips, Wires of higher diameter etc

Temperature Range
  • T1: RT to +60°C
  • T2: RT TO +300°C
  • T3: -70°C to +300°C

Wide Vice Action Grips- TJ 26

About Grips

– Wide Vice-Action Grips are used for conducting tensile tests on a wide variety of materials.

– They are available in different capacities depending on the samples to be tested, and in sizes to accommodate many different specimen dimensions.

– Specimens are quickly clamped in place via a thumbscrew or a butterfly wrench.

– Most of the models are available with serrated faces for gripping soft materials such as plastics, aluminum, and paper, with corrugated faces for gripping fabrics, tissues, leather and other soft materials or rubber faces for gripping plastic film.

Description

Description:

  • This general purpose vice action grip is ideal for testing thin film samples.
  • They feature an easy to use screw action and are fitted with flat, rubber-coated jaw faces.
  • This general purpose, vice action grip is designed to tighten using moveable jaws.
  • The jaw features a tapered nose, which is ideal for very small components or where space is limited.
  • A front thumbscrew ensures quick installation and release of the specimen.
Features
  • Easy To Use: Just align the specimens between the wedges and tighten.
  • Choice of Grip Faces: Choose from serrated, rubber, or corrugated
  • Flexible: Wide temperature range
Applications

Used for tensile testing of paper, rubber, thin plastic film, light fabrics, woven foil, thin sheet materials, threads, fine wire and non-woven textiles as well as for performing 180˚ peel tests.

Temperature Range
  • T1: RT to +60°C
  • T2: RT to +300°C
  • T3: -70°C to +300°C

Split Capstan Grips -TJ 128

About the Grips

– Split capstan grips are typically used for tensile test cordage, rope, flat strapping, and similar flexible materials that might be otherwise difficult to grip without creating undesirable stress concentrations and premature failures.

– Split capstan design exerts constant closing pressure to prevent specimen slippage.

– Capstan can also be configured to accommodate a variety of flexible strapping materials. The capstan grips can be sized and configured for the particular application.

Description

– Split capstan grips are designed to permit faster, easier testing of twisted or braided cords.

– These grips are designed to permit predetermination of specimen length, and allow quick, convenient loading.

– Capstan grips rely primarily on friction to hold the specimen.

– The end of the specimen is clamped lightly between the fixed and movable halves of the split capstan. This holds the specimen while it is being installed.

– Ample radii are provided where the specimen then wraps around the capstan half.

– Typically the circumference and the clamping region of each capstan grip is thermal-sprayed with tungsten carbide particles, of a coarseness appropriate to the particular application.

– This coating greatly increases the effective coefficient of friction of the grips, and thus the holding power.

– However, for some applications, smooth surfaces are both sufficient and desired.

Features
  • Fast easy loading
  • Minimizes jaw breaks
  • Allows predetermination of specimen length
  • Elongation
  • Stress
  • Percentage Elongation
  • Tensile Strength
  • Extension
  • Yield Stress
  • Percentage yield point extension
  • Proof Stress
  • Maximum force
  • Young’s Modulus of Elasticity
  • Also to hold a polished metal plate for 180 degrees peel tests on pressure sensitive tapes etc
Applications
  • Split capstan grips are typically used to tensile test cordage, rope, flat strapping and similar flexible materials that might be otherwise difficult to grip without creating undesirable stress concentrations and premature failures.
  • The capstan grips can be sized and configured for the particular application.
 
Temperature Range

Temperature Range:

RT to +130˚C

Quick Release Bollard Grip–TJ 12

About Grip

– Single bollard grip, these small circular bollard grips are made from graded steel & are designed for testing delicate, flexible samples such as fine threads, wires, and yarns, which may break easily when clamped.

– The free end of the test specimen is held in a vice clamp, the specimen is then wrapped around a single friction bollard; this friction bollard reduces the concentration of stress at the clamping point and prevents premature breakage of the specimen.

– The free end is clamped tightly in place using a pair of friction washers and a thumbscrew. The bollard has a single 5mm wide smooth groove to align the sample centrally and has a diameter of 20mm around which it can be wound.

Features

– This grip has a 12mm diameter bollard, the surface of which can be plain plated steel or rubber coated.

– Because of the offset of the bollard pivot point from the axis of loading, the tension on the sample clamps the tail of the sample between the bollard and the body.

– As the load increases the clamping force increases so the grip is self-tightening. 

– The sample must be flexible enough to wrap around the bollard and conform to its surface.

– All components probably plated for corrosion excellent resistance

Application
  • Fibers
  • Yarns
  • Filaments
  • Twines
  • Thread
  • Fine wire

Chuck Grip -TJ 16

About the grip

These are specially manufactured for small, round dumb-bell metal samples. The special quick load/release slot machined into these grips makes them very easy to use.

Application

Application:  Small, Round , Dumb-belt samples such as miniature metal dumb-bells of the Metric Type B’ size.

Motorized Ring Grip- TJ 101

About Grip

– The grip consists of two anvils 15mm in diameter and 20mm wide.

– The anvils are mounted on shafts carried on ball bearings allowing the anvils to rotate.

– The lower anvil is driven by a small electric motor through a gearbox and is mounted to the lower anchor pin of the testing machine.

– The upper anvil is mounted to the loadcell of the testing machine and is free to rotate.

– The lower anvil speed can be adjusted between 0 and 20 RPM.

– The speed control is mounted in a separate box, which can be positioned to suit the operator.
The grip is used to test loop samples such as ‘O’ rings or rubber bands.

– The sample is placed over both anvils and rotated by the electric motor while a tensile load is applied by the testing machine.

– In this way, stress in the sample is equalized through its length. The grip can be used for applied forces up to 10 kN.

Features

– Dak offers a versatile system for tensile testing of rubber O-rings, featuring a special motorized ring grip in conjunction with a Universal Materials Testing Machine.

– O-rings are used for fluid and vacuum sealing in a host of industries including automotive and aerospace.

Applications
  • Seals
  • O-Rings

Hook Grip - HJ 679

About the Grip

Hook tensile of Springs:

  • Tension springs are tightly wound coils that are designed to operate with tension.
  • The spring stretches to a specific length as the load/force is applied to it.
  • In an unloaded position, the loops of the spring are touching, with either a loop or hook attached at one end, and it is when this attachment is directed with force in the direction of tensile that the spring stretches.
Principle

When these components are pulled apart, usually from either side, the spring tries to hold itself together, causing the springing action, until the force is stopped and it can return to its original form.

Application

Springs for tensile strength.

Temperature

Temperature limits: -150˚C to 200˚C (check with the sales team for any additional temperature requirement)

Briquette Grip -TJ 25

About the Grip

– Briquette grips serve a specific purpose in the context of testing samples during procedures such as ASTM C307 – Standard Test Method for Tensile Strength of Chemical-Resistant Mortar, Grouts, and Monolithic Surfacing.

– These grips are designed to provide secure handling and accurate measurement of the tensile strength of various chemical-resistant mortar, grouts, and monolithic surfacing.

– By using briquette grips, researchers and technicians can effectively assess the mechanical properties and durability of these materials in accordance with standardised testing protocols.

Introduction
  1. A Revolutionary Non-Clamping Chuck with Internal Profile for Cast Cement Testing.
  2. Samples can be moulded with the suitable Briquette mould.
Application
  1. Cast cement and resin-bonded sand briquettes.
  2. A very popular application in construction chemical and Adhesive industry
  3. The specimen must conform to BS6319 Part B.
Temperature

Temperature limits: -30 / -70°C

Square Vice Action Grip- TJ 34

About Grip
  • Square Vice-Action Grips are used for conducting tensile tests on a wide variety of materials. They are available in different capacities depending on the samples to be tested, and in sizes to accommodate many different specimen dimensions. Materials particularly well suited for testing in these grips include papers, tissues, aluminum, plastic films, textiles, waxed paper, film containing strip additive and other materials with low and medium tensile strength.
  • Specimens are quickly clamped in place via a thumbscrew or a butterfly wrench.
  • Most of the models are available with serrated faces for gripping soft materials such as plastics, aluminum, and paper, with corrugated faces for gripping fabrics, tissues, leather and other soft materials or rubber faces for gripping plastic film.
Features
  • This general purpose vice action grip is ideal for testing thin film samples.
  • They feature an easy-to-use screw action and are fitted with flat, rubber-coated jaw faces.
  • This general-purpose, vice-action grip is designed to tighten using moveable jaws.
  • The jaw features a tapered nose, which is ideal for very small components or where space is limited.
  • A front thumbscrew ensures quick installation and release of the specimen.
Applications
  • Used for tensile testing of paper, rubber, thin plastic film, light fabrics, woven foil, thin sheet materials, threads, fine wire and non-woven textiles as well as for performing 180˚ peel tests.
Temperature Ranges

Temperature Range: RT to 130˚C

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