Mechanical Wedge Action Grips
Mechanical wedge action grips are ideal for testing hard, round or flat metallic or composite test samples. The wedge action design creates a highly leveraged clamping load that increases as the sample is pulled. The simplicity of our wedge action grip makes it an affordable solution for tensile testing. We offer a wide selection of options in both standard and custom engineered solutions. All of our mechanical wedge action grips will fit any brand of test machine through the use of an adapter.
Wedge Action Grips with Stationary Bodies and Moving Jaws
| Family | Max Force | Max Thickness | Clamp Type |
|---|---|---|---|
| G7W | 5 kN (1,125 lbf) | 8 mm (0.31 in) | Lever arm |
| G256 | 10 kN (2,250 lbf) | 8 mm (0.31 in) | Lever arm |
| G622 | 10 kN (2,250 lbf) | 9 mm (0.35 in) | Lever arm |
| G243 | 20 to 50 kN (4,500 to 11,250 lbf) | 16 mm (0.63 in) | Lever arm |
| G204 | 50 kN (11,250 lbf) | 40 mm (1.57 in) | Gearbox |
| G224 | 50 kN (11,250 lbf) | 60 mm (2.36 in) | Gearbox |
| G208 | 20 to 250 kN (4,500 to 55,000 lbf) | 6 mm (0.24) | Gearbox |
| G109 | 100 to 500 kN (22,500 lbf to 112 kip) | 50 mm (1.97 in) | Gearbox |
| G140W | 600 kN (135 kip) | 50 mm (1.97 in) | Gearbox |
| G45 | 400 to 600 kN (90,000 lbf to 135 kip) | 50 mm (1.97 in) | Gearbox |
Wedge Action Grips with Moving Bodies and Stationary Jaws
| Family | Max Force | Max Thickness | Clamp Type |
|---|---|---|---|
| GB5-300 | 25 to 100 kN (5,500 to 22,500 lbf) | 20 mm (0.8 in) | Rotating arms |
| GT122 | 10 to 500 kN (2,250 lbf to 112 kip) | 21 mm (0.86 in) | Rotating arms |
| G527 | 20 to 250 kN (4,500 to 55,000 lbf) | 16 to 30 mm (0.63 to 1.2 in) | Rotating arms |
| G185 | 100 kN (22,500 lbf) | 16 mm (0.63 in) | Motorized |
G185 Mechanical Wedge Grip
Fits Any Brand Test Machine
Our grips and fixtures will fit any brand of test machine. We offer adapters that allow the grips and fixtures to be used on test machines from TestResources, Instron®, MTS®, Tinius Olsen® and every other brand of machine.
Wedge Action Grips with Stationary Bodies and Moving Jaws Compared to Moving Bodies and Stationary Jaws
TestResources’ stationary bodied wedge action grips with moving jaws provide increased jaw movement and are ideal for high elongation materials. It features a short and compact design that can be beneficial inside environmental chambers or where frame space and travel is limited due to machine constraints or due to large and/or tall samples. This style of wedge grip provides the widest selection and has proven to be simpler for loading samples when comparing other styles. The simplicity of the stationary bodied wedge action grip and spring loaded lever arm clamp tends to make it the most affordable solution to mechanical wedge action grips. The process is generally very simple because all the user has to do is move a lever up and down compared to turning a handle numerous revolutions which can create user fatigue after numerous tests.
TestResources’ moving bodied wedge action grips with stationary jaws, also known as no-shift jaws, are ideal for hard and low elongation materials. This design minimizes or completely eliminates compressive pre-loads that can occur during specimen clamping. The clamp comes in either a rotating arm or motorized clamp depending on the amount of force required and the operator is able to pre-select the exact point that the specimen will be clamped. The stationary jaws do not move vertically while the user is trying to load the sample. Jaw faces move laterally and hold position against the specimen as the grip is tightened which makes sample loading easier. Compressive force and specimen buckling is also eliminated.
Our moving bodied wedge action design with stationary jaws provides an automatic increase of the clamp load while the tensile load is being applied. The clamp load automatically increases the holding power which improves the ‘bite’ and eliminates specimen slippage. This is particularly advantageous when testing high strength hard metals and composites.
This design offers many safety features that eliminate the risk of harm to both the equipment and the operator. For example, during a test, pent-up inertia can build which causes the sample to keep moving in the direction of the applied load. This violent reaction of the pent up inertia can cause the extensometer to go flying off of the sample and damage or break the costly equipment. With the use of moving jaws, the sample is pushed in the opposite direction of the mechanical advantage resulting in the jaws loosening and therefore the sample also loosening which can cause harm to the user and the equipment. With our stationary jaws, the extensometer will stay attached and the sample will not pull loose when the specimen ruptures.
Wedge Action Grips Produce High Clamp Forces Required to Test High Strength Materials
TestResources’ wedge action design produces a highly leveraged strong clamp load that increases as the sample is tightened. As the grip jaws contact the specimen, the clamping force increases as the test load increases. When under load, our grip wedge action adds clamping pressure to minimize specimen slippage. The wedge action design creates natural and automatic centering of the sample specimen to the grip body. The natural centering produces reliable and repeatable alignment of the sample with the test machine’s centerline. We also offer optional centering tools for additional directions of centering which increase repeatability even more. Our wedge action grips are the ideal solution for tensile tests of hard round or flat high strength material.
We also offer pneumatic and hydraulic wedge action grips. Pneumatic and hydraulic action grips are needed when the initial clamping capacity of a mechanical grip is inadequate. They may also be needed when throughput and repeatability on clamp load is important to accurate and consistent test results, especially with composites.
Can be Configured to your Specific Application
We can configure the grips and jaws to fit any sample geometry including round samples like wire and fasteners as well as flat test specimens with or without shoulder tab ends. Our experienced engineers will work with you to ensure your test system is configured to meet your specific application requirements.
Application examples:
- Metals
- Composites
- Wood
- Plastics
- Automotive components
- Aerospace components
Test types:
- Static tensile tests
- Tensile tests
- Tension-tension cyclic tests
- Dynamic fatigue tests
- Limited compression tests
We can configure grips to match specific ASTM, ISO, DIN, EN requirements.
- ASTM A370 for Tensile Tests of Steel Products
- ASTM B557 for Tension Testing Wrought and Cast Aluminum
- ASTM D3039 for Tensile Tests of Advanced Composites
- ASTM E8 for Tensile Tests of Metals
And more...
Compatible with Different Testing Environments
Grips can be constructed of different materials and surface treatments such as stainless steel, titanium and nickel coating. Nickel coated versions can be used inside hot and cold temperature chambers. The nickel coating helps protect the grips from corrosion caused by condensation from the freeze/thaw cycles inside the chamber. It also protects the grips from moisture inside humidity chambers which helps protect the grips from rusting over time. Nickel coated grips or grips made from corrosion resistant materials such as 316 stainless steel or titanium have an important benefit to people whose labs are in humid climates or near coastal areas of the ocean. Stainless steel versions are used in harsh environments. The stainless steel material protects the grips from corrosion.
Standard and Custom Engineered Solutions
We offer multiple standard products as well as custom solutions. Standard grips handle sample thicknesses and sample diameters to 60 mm (2.36 in). However, our modular platform enables us to adjust designs for any application requirement including customized bodies and jaws for larger test samples. We understand that every sample can be unique. These grips can test any type of material from timber to titanium! With this in mind, we offer custom engineered grips and jaw surfaces to match your specimen with any test force. Through the use of some of our standard elements, we can configure a wide variety of unique solutions without paying a “custom price” or waiting months to receive your order. Our modular platform approach satisfies virtually any application requirement.
Wide Range of Supporting Options
Interchangeable Jaws or Jaw Faces - We have various jaws available including standard jaws, wide width jaws, insert jaws and we can also easily custom engineer our jaws to fit unique test samples.
Variety of Jaw Surfaces - We offer a wide variety of jaw surfaces for various sample types including:
- Diamond grit coated and SurfAlloy
- Wave/ Corrugated serrated
- V serrated jaws for round samples
- We also offer custom made jaw surfaces
Specimen Centering Tool - The specimen centering tool provides a settable backstop to ensure repeatable specimen location. This will help keep the specimen appropriately aligned and orientated to the direction of pull, resulting in more consistent test results. This tool adds an additional direction of centering to the natural alignment that our wedge action grip design already produces.
Optional Pneumatic Cylinders - Due to our modular design principles, pneumatic cylinders can be added onto many of our mechanical grip designs, bringing ease of operator use and repeatability at an affordable price. Pneumatic cylinders help to provide increased initial clamp load on samples and thus not allowing the sample to slip. Our pneumatic actuated grips produce active clamping for samples with high Poisson's ratio because samples with high poisson's ratio tend to slip out of the jaws. Pneumatic jaws are beneficial where machine efficiency and throughput is important. Loading time can be significantly reduced with pneumatics. Additionally, operator fatigue is reduced which results in more consistent clamping load from sample to sample and operator to operator. This ensures more accurate and consistent results.
Related Products
There are so many grips to choose from it can be overwhelming and you certainly don’t want to make the mistake of selecting the wrong one. Give us a call today to speak to one of our experienced engineers that will work with you to find the exact solution based on your test requirements.
