Pneumatic Wedge Grips 10-20 kN – Self-Intensifying

Pneumatic wedge grips for slippery and hard-to-hold specimens

Hard steel foils, spring wire and fiber-filled plastics are notorious for slipping in flat-faced grips. The UGC-PG-050 combines pneumatic closing with a self-intensifying wedge: air brings the jaws onto the specimen, and as the tensile load climbs the wedges draw the jaws tighter. Two capacities are offered, 10 kN (2,248 lbf) and 20 kN (4,496 lbf).

How the wedge action works

Pneumatic pressure sets the initial grip, and the pull of the test then wedges the jaws harder against the specimen, so clamping force tracks the load. On the 10 kN grip, clamping reaches 20 kN at 7 bar (102 psi) once 10 kN of tensile load is applied; on the 20 kN grip it reaches 43 kN (9,666 lbf) at 7 bar under 20 kN of load. The stainless steel 10 kN version can be driven to 26 kN clamping at 16 bar (232 psi). The jaws move centrically, closing equally from both sides, so the specimen stays aligned with the load string.

Versions and temperature range

• 10 kN, stainless steel: 33 x 40 mm jaws, 0–16 mm opening by jaw set, -70 to 280 °C (-94 to 536 °F), approx. 2.8 kg per grip

• 10 kN with pull rods: the same grip extended for use inside a temperature chamber

• 20 kN standard: nickel-plated steel body, 50 x 60 mm jaws, 0–20 mm opening, approx. 8.9 kg per grip

• 20 kN, -70 to 280 °C: available with or without pull rod

Jaw sets for the 10 kN grip include pyramid jaws for 0–6, 6–12 and 10–16 mm, V-jaws for round specimens of 2–6 or 6–12 mm, and diamond jaws for 0–6 mm. The 20 kN grip takes pyramid jaws for 0–8, 5–14 and 12–20 mm and V-jaws for 3–20 mm diameters in three ranges. All jaws are hardened steel, 58 HRC, and the grips are supplied without jaws.

Typical applications

Hard steel foils and wires, fiber-reinforced plastics and rubber, and high- and low-temperature tensile work. For metals the grips suit thin-sheet and wire specimens in tests such as ASTM E8 and ISO 6892-1; for filled plastics, specimens like those in ASTM D638.

Choosing between wedge grips

Universal Grip also offers the UGC-PG-170 pneumatic non-shift wedge grip in the same load range. Its jaws move only horizontally to keep axial preload low on brittle materials such as ceramics, whereas the PG-050 lets clamping build with load, which makes it the better choice when slipping, not preload, is the problem. For purely mechanical designs see our wedge grips. Pair the 10 kN grip with a 10 kN Galdabini benchtop frame and the 20 kN grip with a 25 kN or 50 kN frame. For chamber testing, combine the pull-rod versions with our environmental chambers.

Tell us the material, specimen thickness or diameter, test temperature and your frame's coupling, and we will specify the grip, jaws and pull rods. Request a quote.