Wedge Grips

Wedge grips consist of a solid body with interchangeable jaw inserts or fixed jaws, together with an operating unit for opening and closing the grip.
Wedge Grips

Key Advantages and Features

  • The closing force is proportional to the tensile force (self-gripping).
  • Wedge grips always close symmetrically with respect to the tensile axis.
  • Long clamping length and good jaw guiding properties allow contact pressure on the specimen to be kept to a minimum.
  • High temperature resistance and low overall height makes specimen grips ideal for use in temperature chambers.
  • The wedge grip design ensures fast and energy-saving operation using a lever.
  • The lever can be locked when the wedge grips are open.
Body over wedge specimen grips

Body Over Wedge Operating Principle

Wedge grips operating on this principle apply a greater preloading force when the specimen is inserted. The preload applied to the specimen is transmitted to the jaws via the body of the grips using a lead screw. In this case also the main gripping force is not attained until during tensile loading (via the wedge effect). Grips of this type have two additional advantages: Specimens inclined to slippage are gripped more firmly right from the beginning and the gripping length remains constant, even if thickness varies from specimen to specimen. In addition, strain-rate control to ISO 6892-1 (2009) Method A (closed loop) and ASTM E 8 (2009) Method B can be applied with greater precision.

Wedge grips, Fmax 10 kN

One set of grips, two gripping principles.

  • The modular design of the grips allows them to be configured for manual or pneumatic actuation according to requirements.
  • With specimen grips from the 'Body over Wedge' range the position of the jaws remains constant in the test direction as the specimen is gripped. This means that the grip-to-grip separation does not depend on the specimen thickness.
  • The manual version offers a cost-efficient, simple and robust solution. Actuation via the radially mounted lever enables high preload forces.
  • With the pneumatic version the emphasis is on fast, reproducible and, most importantly, parallel gripping. Full gripping force is available right from the start, so that the static jaws transmit the test speed directly to the specimen. When working with a temperature chamber, extensions are simply used. The pneumatic actuator is therefore positioned outside of the chamber.
Body over wedge specimen grips
Wedge grips pneumatic grips body over wedge

Applications

  • Specimen material
    Plastics, reinforced plastics, fiber composites, wood and similar materials
  • Specimen shape
    Flat specimens (strip and dumbbell specimens)
  • Type of loading
    Tensile

Advantages and features

  • Whether you are testing sensitive specimens or specimens with short clamping lengths, these symmetrically designed grips guarantee optimum clamping.
  • When determining the exact nominal strain the grip-to-grip separation does not depend on specimen diameter. This minimizes set-up time.
  • Reduced weight plus a compact design simplify handling, ensure short heating and cooling times in the temperature chamber. and enable long travel.
  • Absolutely secure gripping right from the start of the test for specimens prone to light slippage.

Technical data, Fmax 10 kN (body over wedge)

Item No.

1004955[1]

Type

8304

Operating principle/identification

Wedge action

Test load, max. (Fmax)

10

kN

Dimensions:

Height with actuation lever

195

mm

Width

130

mm

Width with actuation lever

207

mm

Depth

73

mm

Depth with actuation lever

207

mm

Opening width, max.

6.5

mm

Gripping of the specimen

At least 20 mm

Weight:

Per specimen grip (without jaws), approx.

5.2

kg

Jaws (pair)

0.75

kg

Optional stopper system

0.5

kg

Connection

Ø 20

mm

Ambient temperature

-70 to +250

°C

Scope of delivery

2

pieces

  1. A load cell with a limit torque of at least 300 Nm is required (for example type Xforce K).
Body over wedge specimen grips

Wedge Grips

Fmax 50 kN
  • Specimen material:
    Ferrous and non-ferrous metals, hard and toughened plastics, fiber composites, wood, similar materials
  • Specimen shape:
    Round specimens, flat specimens, with or without reinforced ends (strip specimens or dumbbells)
  • Type of loading:
    Tensile

Advantages and features

  • When determining exact nominal strain the grip-to-grip separation does not depend on specimen diameter. This minimizes set-up time.
  • Absolutely secure gripping right from the start of the test for specimens prone to light slippage.
  • The wedge grips are ideal for alignment-critical applications (including Nadcap accreditation) and for specimens with a very low weight which are sensitive to transverse tensile forces.
  • LH/RH thread on actuation lever allows tensioning of specimen when closing via the same rotary motion, avoiding twisting.
  • Specimen geometries requiring large opening widths can also be accommodated by these grips.
  • Depth stops are provided on the flat jaws as standard. A separate height and depth-adjustable stop is also available.
  • Tool-free jaw changes ensure rapid changeover between different specimens.

Technical data, Fmax 50 kN

Description

Value

Item no.

1006757[1]

Type

8404

Operating principle/identification

Wedge action

Test load, max. (Fmax)

50

kN

Gripping ranges:

Flat specimens

0 ... 6.5

mm

Flat specimens

6.5 ... 12

mm

Flat specimens

12 ... 17.5

mm

Flat specimens

17.5 ... 22

mm

Round specimens

Ø4 ... 7.5

mm

Round specimens

Ø7.5 ... 11.5

mm

Round specimens

Ø11.5 ... 14

mm

Round specimens

Ø14 ... 16.5

mm

Round specimens

Ø16.5 ... 19

mm

Gripping length, max.

60

mm

Gripping width, max.

35/60

mm

Dimensions:

Height

224

mm

Width

170

mm

Width with actuation lever

220

mm

Depth

97

mm

Depth with actuation lever

220

mm

Opening width, max.

22

mm

Gripping of the specimen

The specimen must be gripped above at least 2/3 of the jaw height.

Weight:

Weight per specimen grip, approx.

11

kg

Weight of jaws (pair)

0.75

kg

Optional stopper system

0.5

kg

Connection

Ø 36

mm

Ambient temperature

-70 ... +250

°C

Scope of delivery

2

pieces

  1. Recommended and approved for strain rate control in accordance with standards DIN EN ISO 6892-1:2009 and ASTM E 8 – 09.
Body over wedge specimen grips

Wedge Grips

Fmax 100 kN
  • Specimen material:
    Ferrous and non-ferrous metals, hard and toughened plastics, fiber composites, wood, similar materials
  • Specimen shape:
    Round specimens, flat specimens, with or without reinforced ends (strip specimens or dumbbells)
  • Type of loading:
    Tensile

Advantages and features

  • The wedge grips are ideal for alignment-critical applications (including Nadcap accreditation) and for specimens with a very low weight which are sensitive to transverse tensile forces.
  • The preset clamping length is independent of specimen thickness or diameter.
  • High gripping force can be applied.
  • The standard jaws have a very long clamping length (60 mm) which is necessary for extremely grip-sensitive specimens.
  • The wedge grips are symmetrical and, therefore, always close to the tensile axis.
  • Depth stops are mounted on the specimen stops as standard.
  • Use of left and right-hand threads allows both grip units to have the same operating direction, allowing convenient specimen gripping.
  • Positive clamping prevents torsion loads on the specimen during the closing movement.
  • An adapter plate and separate limit switch stop are also available. The stop is adjustable for height and depth.

Technical data, Fmax 100 kN

Item no.

080384[1]

Type

8504

Test load, max. (Fmax)

100

kN

Height

260

mm

Width

200

mm

Width with actuation lever

236

mm

Depth

94

mm

Depth with actuation lever

236

mm

Opening width, max.

22

mm

Gripping of the specimen, min.

30

mm

Weight of jaws (pair)

1.1

kg

Weight per specimen grip, approx.

18

kg

Connection

Ø 60

mm

Ambient temperature

-70 to +250

°C

Scope of delivery

2

pieces

  1. First recommended and approved for strain rate control in accordance with standards DIN EN ISO 6892-1:2009 and ASTM E 8 – 09.
Wedge Grips

Lever Operating Principle

Wedge grips operating on this principle are self gripping. During insertion a preload is applied to the specimen via operation of the lever and a spring. However, it is only during tensile loading that the main gripping force is attained via the wedge effect. The gripping pressure maintains a constant relationship to the tensile force through displacement of the wedges. The advantage of grips of this type is that the test can be performed very quickly and does not require the operator to exert too much force.

Wedge Grips

Wedge Grip

Fmax 2.5 kN to 20 kN
  • Specimen material:
    Ferrous and non-ferrous metals, hard and toughened plastics, fiber composites, wood, similar materials
  • Specimen shape:
    Round specimens, flat specimens, with or without reinforced ends (strip specimens or dumbbells)
  • Type of loading:
    Tensile

Advantages and features

  • The wedge grips are symmetrical and, therefore, always close to the tensile axis.
  • Long clamping length and good jaw guiding properties allow contact pressure on the specimen to be kept to a minimum.
  • Fast opening and closing via lever and optional locking when wedge grips are open.

Technical data, Fmax 2.5 kN

Item No.

320454

353408

Type

8201 PL[1]

8201

Test load, max. (Fmax)

2.5

2.5

kN

Height

145

145

mm

Width

120

120

mm

Depth

58

58

mm

Depth with actuation lever

159

159

mm

Gripping of the specimen

The specimen must be gripped above at least 2/3 of the jaw height.

The specimen must be gripped above at least 2/3 of the jaw height.

Opening width, max.

11

11This opening width results when using the jaw mountings mentioned below and jaws with 5-mm jaw strength.

mm

Weight per specimen grip, approx.

2.4

1.9

kg

Connection

Ø 20

Ø 20

mm

Ambient temperature

+10 to +35

+40 to +250

°C

Scope of delivery

1

2

piece

Jaws supplied

Surface

Fsc[2] 0.75

Not supplied

mm

Gripping area (H x W)

40 x 32

Not supplied

mm

Hardness

61 HRC

Not supplied

  1. PL = ProLine
  1. Fsc = fish scale

Technical data, Fmax 5 kN

Item No.

320456

318975

Type

8201 PL[1]

8201

Test load, max. (Fmax)

5

5

kN

Height

145

145

mm

Width

120

120

mm

Depth

58

58

mm

Depth with actuation lever

159

159

mm

Gripping of the specimen

The specimen must be gripped above at least 2/3 of the jaw height.

The specimen must be gripped above at least 2/3 of the jaw height.

Opening width, max.

11

11

mm

Weight per specimen grip, approx.

2.4

1.9

kg

Connector

Ø 20

mm

Ambient temperature

+10 to +35

-40 to +250

°C

Scope of delivery

1

2

pieces

Jaws supplied

Surface

Fsc[2] 0.75

Not supplied

mm

Gripping area (H x W)

40 x 32

Not supplied

mm

Hardness

61 HRC

Not supplied

  1. PL = ProLine
  1. Fsc = fish scale

Technical data, Fmax 10 kN

Item No.

320458

318884

Type

8302 PL[1]

8302

Test load, max. (Fmax)

10

10

kN

Height

165

165

mm

Width

156

156

mm

Depth

83

83

mm

Depth with actuation lever

197

197

mm

Gripping of the specimen

The specimen must be gripped above at least 2/3 of the jaw height.

The specimen must be gripped above at least 2/3 of the jaw height.

Opening width

0 to 12.5

0 to 12.5/8" 20.5[2]

mm

Weight per specimen grip, approx.

8

6.5

kg

Connection

Ø 20

Ø 20

mm

Ambient temperature

+10 to +35

-40 to +250

°C

Scope of delivery

1

2

piece

Jaws supplied

Surface

Fsc[3] 0.75

Not supplied

mm

Gripping area (H x W)

50 x 60

Not supplied

mm

Hardness

61 HRC

Not supplied

  1. PL = ProLine
  1. Depending on the jaws used
  1. Fsc = fish scale

Technical data, Fmax 20 kN

Item No.

320460

318886

Type

8302 PL[1]

8302

Test load, max. (Fmax)

20

20

kN

Height

177

177

mm

Width

156

156

mm

Depth

83

83

mm

Depth with actuation lever

197

197

mm

Opening width, max.

12.5

12.5 to 20.5[2]

mm

Weight per specimen grip, approx.

8

6.5

kg

Connection

Ø 36

Ø 36

mm

Ambient temperature

+10 to +35

-40 to +250

°C

Scope of delivery

1

2

piece

Jaws supplied

Surface

Fsc[3] 0.75

Not supplied

mm

Gripping area (H x W)

60 x 50

Not supplied

mm

Hardness

61 HRC

Not supplied

  1. PL = ProLine
  1. Depending upon the jaws used
  1. Fsc = fish scale
Wedge grips

Wedge Grips

Fmax 10 kN & 50 kN

These specimen grips generate extremely high gripping forces

  • Specimen material
    Ferrous and non-ferrous metals, wires
  • Specimen shape
    Round specimens, flat specimens, with or without reinforced ends (strip specimens or dumbbells)
  • Type of loading
    Tensile

Advantages and features

  • Wedge grips with gripping forces up to 0 kN produce approximately 4 times the tensile force.
  • Wedge grips are ideal for the testing of wires due to the long clamping length and the low contact pressure on the specimen.
  • They are symmetrical and, therefore, always close to the tensile axis.
  • Fast opening and closing via lever and optional locking when wedge grips are open.

Technical data, Fmax 10 kN (wires) 

Item no.

313492

Type

8303

Test load Fmax

10

kN

Height

110

mm

Height with closed jaws

114

mm

Width

81

mm

Width with actuation lever

111

mm

Depth

74

mm

Depth with actuation lever

186

mm

Gripping of the specimen

The specimen must be gripped above at least 2/3 of the jaw height.

Opening width, max.

4.5

mm

Connection

Ø 20

mm

Ambient temperature

-40 to +250

°C

Weight per specimen grip, approx.

3

kg

Scope of delivery

2

pcs

Technical data, Fmax 50 kN (wires) 

Type

8403

Item No.

313610

Maximum test load, (Fmax)

50

kN

Height

196

mm

Height with closed jaws

206

mm

Width

144

mm

Width with actuation lever

191

mm

Depth

88

mm

Depth with actuation lever, max.

215

mm

Gripping of the specimen

The specimen must be gripped above at least 2/3 of the jaw height.

Opening width, max.

10

mm

Connection

Ø 36

mm

Ambient temperature

-40 ... +250

°C

Weight per specimen grip (without jaws), approx.

5

kg

Scope of delivery

2

pieces

Wedge grips

Wedge Grips

Fmax 30 kN & 50 kN
  • Specimen material:
    Ferrous and non-ferrous metals, hard and toughened plastics, fiber composites, wood, similar materials
  • Specimen shape:
    Round specimens, flat specimens, with or without reinforced ends (strip specimens or dumbbells)
  • Type of loading:
    Tensile

Advantages and features

  • Small load cells, specimen grips and test tools can be quickly accommodated via the optional mounting unit without having to dismantle the specimen grips.
  • They are symmetrical and, therefore, always close to the tensile axis.
  • Various jaw inserts in different shapes and with a variety of surfaces can be used with these grips, therefore offering a wide range of use.
  • The standard jaws have a very long clamping length (60 mm) which is necessary for extremely grip-sensitive specimen.
  • Special jaws with a short clamping height (40 mm) where a grip-to-grip separation of 20 mm is sufficient are available for testing specimens with short grip-to-grip separation.
  • The very large opening width guarantees optimum utilization of the grips.
  • Smaller wedge grips can be mounted via the adaptation of a T-slotted system.
  • Depth stops are mounted on the specimen stops as standard.
  • A separate limit switch stop is also available. The stop is adjustable for height and depth.

Technical data, Fmax 30 kN and Fmax 50 kN

Wedge Grips

Wedge Grip

Fmax 100 kN to 250 kN
  • Specimen material:
    Ferrous and non-ferrous metals, hard and toughened plastics, fiber composites, wood, similar materials
  • Specimen shape:
    Round specimens, flat specimens, with or without reinforced ends (strip specimens or dumbbells)
  • Type of loading:
    Tensile

Advantages and features

  • They are symmetrical and, therefore, always close to the tensile axis.
  • Fast opening and closing via lever and optional locking when wedge grips are open.
  • Various jaw inserts in different shapes and with a variety of surfaces can be used with these grips, therefore offering a wide range of use.
  • The standard jaws have a very long clamping length (60 mm) which is necessary for extremely grip-sensitive specimen.
  • The very large opening width guarantees optimum utilization of the grips.
  • Small load cells, specimen grips and test tools can be quickly accommodated via the optional mounting unit.
  • Smaller wedge grips can be mounted via the adaptation of a T-slotted system.
  • Depth stops are mounted on the specimen stops as standard.
  • A separate limit switch stop is optionally available. The stop is adjustable for height and depth.

Technical data, Fmax 100 kN

Item no.

320129

Type

8502

Operating principle/identification

Wedge action

Test load, max. (Fmax)

100

kN

Height

210

mm

Width

253

mm

Depth

88

mm

Depth with actuation lever

291

mm

Gripping of the specimen

The specimen must be gripped above at least 2/3 of the jaw height.

Opening width and specimen thickness, max.

See table of jaws

Weight per specimen grip (without jaws), approx.

27

kg

Connection

Ø 60

mm

Ambient temperature

-40 ... +250

°C

Scope of delivery

2

pieces

Technical data, Fmax 150 kN

Item no.

324550

Type

8509

Test load, max. (Fmax)

150

kN

Height

255

mm

Width with actuation lever

395

mm

Depth with actuation lever

291

mm

Gripping of the specimen

The specimen must be gripped above at least 2/3 of the jaw height.

Opening width, max.

32

mm

Weight per specimen grip (without jaws), approx.

47

kg

Weight per jaw, approx.

2.0 to 2.5

kg

Connection

Ø 60

mm

Ambient temperature

-40 to +250

°C

Scope of delivery

2

pieces

Technical data, Fmax 250 kN

Item No.

600619

317045

Type

8509

8509[1]

Test load, max. (Fmax)

250

250

kN

Height

320

320

mm

Width

350

350

mm

Depth with actuation lever and/or connector unit

356

241

mm

Gripping of the specimen

The specimen must be gripped above at least 2/3 of the jaw height.

The specimen must be gripped above at least 2/3 of the jaw height.

Opening width and specimen thickness

See table of jaws

See table of jaws

Weight per specimen grip (without jaws), approx.

70

75

kg

Connection

Ø 60

Ø 60

mm

Ambient temperature

-40 to +100

+10 to +35

°C

Scope of delivery

2

2

pieces

  1. Includes pneumatic actuator. A pneumatic controlled unit is required.
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