Side loading specimen grip
AssigneeMTS Systems Corporation
InventorJohn A. Christiansen
Life of this patent
Estimating the term…
Abstract
Hydraulically actuated grips are constructed to permit loading of specimens from either side of the grips. The grips are particularly adapted for use with flat specimens, are easily actuated, and are symmetrically designed so that when actuated, the grips do not exert any substantial axial load on the specimen and a uniform clamping force is applied laterally across the specimen. In addition, the grips, which can be used for either tensile or compressive loading, do not exert any bending moment on the specimen during test loading.
Claims12
A side loading specimen grip assembly suitable for use in both tensile and compressive loading of a specimen comprises a main mounting body, said main mounting body being adapted to be loaded by an actuator in direction along a longitudinal axis, means on said main mounting body defining a slide on an upper surface thereof, jaw means mounted on said slide for movement transverse to the longitudinal axis, said jaw means comprising a pair of opposed grip jaws mounted on said slide for simultaneous longitudinal movement therewith when the mounting body is loaded by the actuator, the grip jaws being movable toward and away from each other and having wedge surfaces thereon, a housing mounted on said main mounting body and having cam surfaces mating with said wedge surfaces so that upon movement of the housing relative to the mounting body along said longitudinal axis in a first direction the cam surfaces force said jaws to move toward each other, and cooperating cylinder and piston means between said main mounting body and said housing forming a chamber into which hydraulic fluid under pressure may be introduced to force the housing in direction along the longitudinal axis to tend to force the cam surfaces against the wedge surfaces and force the grip jaws together, said housing having a first recess so that the side portions of said grip jaws are accessible from the exterior of said housing and above the mounting body to permit installation and removal of a specimen from a side of the grip jaws and specimen grip assembly without the need for longitudinal movement of the grip jaws.
A side loading specimen grip assembly suitable for use in both tensile and compressive loading of a specimen comprises a main mounting body having a neck and an enlarged upper piston portion, means on said neck adapted to be attached to an actuator for movement of said main mounting body in direction along its longitudinal axis, a pair of grip jaws mounted for movement longitudinally simultaneously with the mounting body, the grip jaws being mounted on the end of said piston portion opposite from the neck and for movement transversely to the longitudinal axis, said grip jaws being generally centered along said longitudinal axis and movable transversely toward and away therefrom, and having side surfaces on opposite sides of a plane defined by said longitudinal axis and a line extending in the direction of movement of said grip jaws, said grip jaws having outwardly and upwardly facing wedge surfaces, a housing member, said housing member including a first portion having a bore therethrough which surrounds said neck and said piston portion, and forms a pressure tight chamber with respect to said piston portion on a side of said piston portion such that pressure in said chamber tends to move said housing in direction along the longitudinal axis, said housing having a second section partially surrounding said grip jaws including a pair of cam surfaces adapted to mate with the wedge surfaces of said grip jaws, movement of said housing when pressure is in said chamber causing said cam surfaces to engage the grip jaws and urge the grip jaws toward each other, said second section of said housing having a recess on one side therefore open to said cam surface so that substantially the entire sides of both of the grip jaws are accessible from the exterior of said outer housing, and said outer housing surrounding the rest of the portions of said grip jaws and the housing recess permitting insertion and removal of specimens laterally from the space between the grip jaws when the grip jaws are separated without the need for longitudinal movement of the grip jaws to facilitate specimen installation and removal.
A symmetrical side loading specimen grip assembly suitable for use in both tensile and compressive loading of a specimen comprises:
- a main mounting body, said main mounting body being adapted to be loaded by an actuator in direction along a longitudinal axis;
- means on said main mounting body defining a slide on an upper surface thereof;
- jaw means mounted on said slide for movement transverse to the longitudinal axis, said jaw means comprising a pair of opposed grip jaws that are movable toward and away from each other and the axis and having wedge surfaces thereon;
- a housing mounted on said main mounting body about the axis and having cam surfaces mating with said wedge surfaces so that upon movement of the housing relative to the mounting body along said longitudinal axis in a first direction the cam surfaces force said jaws to move simultaneously toward the axis and each other;
- cooperating cylinder and piston means between said main mounting body and said housing forming a first annular chamber extending concentrically about the axis into which hydraulic fluid under pressure may be introduced to force the housing in a first direction along the longitudinal axis to tend to force the cam surfaces against the wedge surfaces and force the grip jaws uniformly together;
- and
- said housing being generally symmetrical and having a pair of opposed identical recesses therein so that the side portions of said grip jaws are accessible from opposite sides of the exterior of said housing and above the mounting body.
A symmetrical side loading specimen grip assembly suitable for use in both tensile and compressive loading of a specimen along a longitudinal test axis comprises:
- a main mounting body having a neck and an upper piston portion, means on said neck adapted to be attached to an actuator for movement of said main mounting body in direction along the longitudinal axis;
- a pair of grip jaws mounted for movement on the end of said piston portion opposite from the neck and for movement transversely to the axis, said grip jaws being centered along said longitudinal axis and movable transversely toward and away therefrom, and having side surfaces on opposite sides of a plane defined by said longitudinal axis and a line extending in the direction of movement of said grip jaws, said grip jaws having outwardly and upwardly facing wedge surfaces;
- a housing, said housing including first and second sections which combine to concentrically surround said neck and form a pressure tight chamber with respect to said main mounting body on a side of said piston portion such that pressure in said chamber tends to move said housing in direction along the longitudinal axis, the second section of the housing partially surrounding said grip jaws and including a pair of cam surfaces adapted to mate with the wedge surfaces of said grip jaws, movement of said housing when pressure is in said chamber causing said cam surfaces to engage the grip jaws and urge the grip jaws simultaneously toward the longitudinal axis and each other;
- and
- said second portion of said housing having a pair of opposed identical recesses open to said cam surfaces so that substantially the entire sides of both of the grip jaws are accessible from opposite sides of the exterior of said outer housing, and said outer housing surrounding the rest of the portions of said grip jaws and the housing recesses permitting insertion and removal of specimens laterally from the space between the grip jaws when the grip jaws are separated.
Dependencies are inferred from the claim text.