Grips Employing Deflection (Capstan Grips)

A load reduction curve is used for this specimen grip. The force in the specimen is reduces over the course of the load reduction curve. The required gripping forces can be reduced in the pneumatic control unit. Maximum test load ranges from 500 N to 20 kN.

Key Advantages and Features

  • With pneumatic end clamping the gripping force remains constant, allowing high specimen throughput.
  • Automatic centering of specimens via guide grooves in the load reduction curve.
  • No transverse forces are transmitted to the load cell via the specimen grips.
  • The symmetrical weight distribution allows the center of gravity of the grips to be near the tensile axis.
1x1-04-pn-5kn-defl-belt-fo

Grips with 180° Deflection

  • Specimen material:
    Metals, paper, textiles, elastomers, insulating material, and similar materials
  • Specimen shape:
    Round and flat specimens, thread, twine, belts, bands
  • Type of loading:
    Tensile

Advantages and features (180° deflection)

  • For specimens prone to shrinkage, the gripping force is uniformly maintained by the constant pneumatic pressure.
  • The contact force on the specimen is reproducible.
  • Dove-tail jaw system enables easy, tool-free insert change. A wide variety of fixed focus lenses are available.

A load reduction curve is used for this specimen grip.

The specimen grip can also be used without the load reduction curve. A second connector is included so that the specimen can be held in the tensile axis.

Technical data, Fmax 5 kN

Maximum test load (Fmax)

5

kN

Item no.

315008

Type

8388

Operating principle/identification

Pneumatic with 180° direction changer

Operating pressure

1 ... 10

bar

Maximum closing force at 6 bar

5

kN

Dimensions:

Height

182

mm

Width

238

mm

Depth

130

mm

Depth with connection unit

168

mm

Maximum gripping travel

5

mm

Maximum opening width

5

mm

Weight per specimen grip (without jaws and load reduction curve), approx.

6.6

kg

Connection

Ø 20

mm

Ambient temperature

+10 ... +35

°C

Scope of delivery

2

pieces

Grips with 90° Deflection

  • Specimens:
    Textile spinning yarn and continuous filaments very fine, tire cord up to approx. 300 N, plastic and metal wires, foil bands up to 5 mm wide
  • Type of loading:
    Tensile

Advantages and features (90° deflection)

  • For specimens prone to shrinkage, the closing force is uniformly maintained by constant pneumatic pressure.
  • The contact force on the specimen is reproducible.
  • Automatic centering of specimen via guide groove.

Function description

Function Description

A reduction curve is used for this specimen grip. The force in the specimen is reduces over the course of the load reduction curve. The specimen is held by the pneumatic end clamp. The required gripping forces can be reduced in the pneumatic control unit by the load reduction curve.

The specimen grip can also be used without the load reduction curve. To do so, it is mounted at a 90° (see illustration).

Technical data, Fmax 1 kN

Item no.

344647

014771

Type

8190

8190

Test load, max. (Fmax)

1

1

kN

Closing force, max. at 6 bar

4.2

4.2

kN

Pressure, min.

1

1

bar

Pressure, max.

6

6

bar

Height

105

105

mm

Width

115

115

mm

Depth

75

75

mm

Depth with connection unit

93

93

mm

Gripping travel

5

5

mm

Opening width, max.

5

5

mm

Weight per specimen grip (without jaws and load reduction curve), approx.

1.4

1.4

kg

Connection diameter

8

20

mm

Ambient temperature

+10 to +35

+10 to +35

°C

Scope of delivery

2

2

pieces

Grips employing deflection (capstan grips)

Double Deflect Grips

  • Probenmaterial:
    Hochdehnbare, fadenförmige Werkstoffe wie Gummifäden und Elastofasern
  • Probenform:
    Faden
  • Beanspruchungsart:
    Zug

Advantages and features (double deflection)

  • These specimen grips ensure exact strain measurement on high-extension threads.
  • The structural design prevents jaw breaks and enables slip-free testing.
  • Frictional forces between rollers and specimen eliminates slippage of the specimen.

Function description

The double capstan grips can be used to grip threads and thread-like tensile specimens.

With this deflection principle a force slope occurs in two stages. The specimen break takes place in the gage length without causing slippage of the specimen on the lower roller or jaw breaks.

The specimen is looped over the load cell roller. The specimen is then deflected to a lower roller and guided to a third height-adjustable roller.

After the deflection of the double thread, a pre-load weight (not included in scope of delivery) is attached. During this stage all three rollers are movable. The extensions, which are created when the pre-load weight is attached, are balanced. The three lengths are aligned to the material being tested.

The double thread is clamped into the wedge grip. This is also height adjustable.

After the specimen grip is closed the deflection rollers are locked. Frictional forces between the rollers and the specimen prevents slippage of the specimen. The roller diameter is dimensioned in such a way that the occurring friction does not influence the test results.

A specimen grip with constant gripping force is used to clamp the double thread because the specimen to be tested can frequently slip out from between the gripping areas.

Technical data, Fmax 0.5 kN

Item No.

317800

Type

8170

Test load, max. (Fmax)

0.5

kN

Specimen diameter, max.

5

mm

Deflection rollers radius

10

mm

Upper specimen grip

Height

159

mm

Width

119

mm

Depth

72

mm

Width with clamping lever

153

mm

Weight

0.7

kg

Connection diameter

8

mm

Lower specimen grip

Height

180

mm

Width

93

mm

Depth

62

mm

Depth with clamping lever

94

mm

Weight, approx. (with wedge screw grip)

1.3

kg

Connection

Ø 20

mm

Ambient temperature

+10 to +35

°C

Scope of delivery

Set[1]

  1. Upper and lower specimen grip, one wedge screw grip Type 8106, Fmax 500 N
Grips employing deflection (capstan grips)

Specimen Grip for Tire Cords

  • Prüfungen z. B. nach ASTM D 885:
  • Probenmaterial:
    Reifencorde, Zwirne, Garne
  • Probenform:
    Seile, Schnüre
  • Beanspruchungsart:
    Zug

Advantages and features (tire cords)

  • The ends are clamped pneumatically, ensuring that the gripping force remains constant even with diminishing specimen diameter.
  • Force reduction curve employing 180° deflection reduces the tensile force on the end clamping position. Specimen is securely held preventing jaw breaks during the test.
  • A guide mandrel and a depth stop allow fast and convenient specimen feeding.
  • A guide groove is integrated into the load reduction roller for thread feeding, thereby positioning the specimen automatically and precisely in the tensile axis.
  • Easy and convenient opening and closing via pneumatic control unit allowing high specimen throughput.

Technical data, Fmax 2.5 kN

Item no.

326020

Type

8297

Operating principle/identification

Tire cord; pneumat. End clamping

Test load, max. (Fmax)

2.5

kN

Closing force at 6 bar

5.8

kN

Pressure, min.

3

bar

Pressure, max.

10

bar

Height

183

mm

Width

215

mm

Depth

72

mm

Depth with guide mandrel

109

mm

Depth with guide mandrel and connector unit

134

mm

Gripping travel

4

mm

Opening width, max. (with jaws)

4

mm

Weight per specimen grip (with jaws), approx.

4

kg

Connection

Ø 20

mm

Ambient temperature

+15 ... +35

°C

Scope of delivery

2

pieces

Jaws supplied

Steel, ground

Gripping area (H x W)

60 x 32

mm

Grips for High-Strength Plastic Yarn

  • Probenmaterial:
    Hochfeste Kunststoffgarne zur Verarbeitung in Seilen, Netzen, Tauwerken, Textilien, Helmen und Westen
  • Probenform:
    Garn
  • Beanspruchungsart:
    Zug

Advantages and features (plastic yarns)

  • The symmetrical weight distribution allows the center of gravity of the grips to be near the tensile axis. No transverse forces are transmitted to the load cell via the specimen grip.
  • A guide mandrel and a depth stop allow fast and convenient specimen feeding.
  • A guide groove is integrated into the load reduction roller for thread feeding, thereby positioning the specimen automatically and precisely in the tensile axis.
  • The ends are clamped pneumatically, ensuring that the gripping force remains constant even with diminishing specimen diameter.
  • Force reduction curve employing 180° deflection reduces the tensile force on the end-clamping position. The closing force is progressively loaded at end clamping, thereby securely holding the specimen and preventing jaw breaks during the test.
  • Easy and convenient opening and closing via pneumatic control unit allowing high specimen throughput.

Technical data, Fmax 2.5 kN

Item no.

070255

Type

8297

Working principle

Pneumatic, single-side closing

Test load, max. (Fmax)

2.5

kN

Closing force at 6 bar

16

kN

Pressure, min.

3

bar

Pressure, max.

10

bar

Gripping range:

Opening width, max.

4

mm

Connection

Ø 20

mm

Dimensions:

Height

183

mm

Width

232

mm

Width with pneumatic connection

267

mm

Depth

100

mm

Depth with guide mandrel

116

mm

Depth with guide mandrel and connection unit

126

mm

Weight, approx.

6.1

kg

Ambient temperature

+15 to +35

°C

Scope of delivery

2 pieces

Grips employing deflection (capstan grips)

Grips for Yarn

  • Probenmaterial:
    Hochfeste und klemmempfindliche Garne, sehr glatte Multifilament-Garne, Corde, Metalllitzen, Glascordlitzen
  • Probenform:
    Garn
  • Beanspruchungsart:
    Zug

Advantages and features (yarn)

  • The ends are clamped pneumatically, ensuring that the gripping force remains constant even with diminishing specimen diameter.
  • Interchangeable load reduction curves for optimum matching to specimen material.
  • Various jaw inserts are available for different specimen materials and diameter ranges.
  • Quick, easy specimen insertion requires little effort, making these grips suitable for series testing.
  • Automatic centering of specimen via guide grooves.

Technical data, Fmax 2.5 kN

Item No.

353413

Test load Fmax

2.5

kN

Type

8297

Max. closing force at 6 bar

16

kN

Max. closing force at 10 bar

27

kN

Pressure, min.

1.5

bar

Pressure, max.

10

bar

Height

254

mm

Width

358

mm

Depth

100

mm

Opening width, max. (with jaws)

5

mm

Connection

Ø 20

mm

Ambient temperature

+10 to +35

°C

Weight per specimen grip (without jaws), approx.

7.5

kg

Scope of delivery

2

pieces

Specimen grip for steel strip cord

  • Proben:
    Stahlreifencorde nach BISFA-Norm, Metalldrahtlitzen und textile Garne, Zwirne und Seile
  • Beanspruchungsart:
    Zug

Advantages and features (steel strip cord)

  • The symmetrical weight distribution allows the center of gravity of the grips in the tensile axis. No transverse forces are transmitted to the load cell via the specimen grips.
  • A guide groove is integrated into the load reduction roller and basic unit for thread feeding, allowing fast and convenient specimen feeding and automatic and precise positioning in the tensile axis.
  • Force reduction curve employing 270° deflection reduces the tensile force on the end-clamping position. Thus the required closing force can be reduced at end clamping for specimens that are sensitive to clamping. The closing force is progressively loaded at end clamping, thereby securely holding the specimen and preventing jaw breaks during the test.
  • The load reduction radius is reduced seamlessly via the involute form of the load reduction roller.
  • The ends are clamped pneumatically, ensuring that the gripping force remains constant even with diminishing specimen diameter.
  • Easy and convenient opening and closing via pneumatic control unit allowing high specimen throughput.

Technical data, Fmax 10 kN

Item no.

012415

Test load, max. (Fmax)

10

kN

Type

8397

Working principle

pneumatic, single-side closing

Closing force at 6 bar

30

kN

Closing force at 10 bar

50

kN

Pressure, min.

1

bar

Pressure, max.

10

bar

Height

220

mm

Width

369

mm

Depth

113

mm

Depth with connection unit

157

mm

Opening width, max. (with jaws)

5

mm

Weight per specimen grip, approx.

12.5

kg

Connection

Ø 20

mm

Ambient temperature

+10 to +35

°C

Scope of delivery

2

pieces

Supplied load reduction curve

Length per curve, approx.

330

mm

Deflection angle

270

°

Jaws supplied

Surface

Steel, smooth, hardened

Gripping length, max.

60

mm

Hardness

58 HRC

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