초록 ▼

A screw-type lifting clamp comprising a generally U-shaped clamp body having a pair of spaced, opposed projections defining a generally vertically downwardly facing material receiving slot, a lifting shackle attached to said clamp body, a screw threadedly received through a first such body projectio

A screw-type lifting clamp comprising a generally U-shaped clamp body having a pair of spaced, opposed projections defining a generally vertically downwardly facing material receiving slot, a lifting shackle attached to said clamp body, a screw threadedly received through a first such body projection and being threadedly movable toward and away from the second body projection, a jaw pivotally mounted to the second body projection for pivotable movement about a horizontal axis perpendicular to the screw axis, and resilient means urging the jaw to a horizontal position. The pivotable jaw includes vertically spaced teeth defining a gripping surface which is convex in a vertical plane and has a radius of curvature greater than the horizontal distance between the jaw pivotal axis and the jaw gripping surface when that jaw is horizontal.

대표청구항 ▼

A screw-type clamp for lifting material such as metal plates, comprising: a clamp body having generally an inverted U-shaped configuration when in normal vertical lifting orientation with spaced, opposed first and second projections defining a generally vertically downwardly facing material receivin

A screw-type clamp for lifting material such as metal plates, comprising: a clamp body having generally an inverted U-shaped configuration when in normal vertical lifting orientation with spaced, opposed first and second projections defining a generally vertically downwardly facing material receiving slot therebetween open at its outer end; a lifting shackle for lifting said clamp, attached to said clamp body adjacent the inner end of said slot and extending generally vertically upwardly from said body; a screw having a shaft threadedly received through the first said body projection for rotation about a first horizontal axis, said screw having a first end fixed against vertical movement and defining a material gripping surface extending into said slot toward the second said body projection, said screw being threadedly movable horizontally toward and away from said second body projection; a jaw mounted to said second body projection and having vertically spaced teeth defining a material gripping surface extending into said slot and opposing said material gripping surface of said screw so that threaded movement of said screw toward said jaw urges material in said slot into a gripping relationship between the material gripping surfaces of said jaw and said screw, said jaw being pivotable about a second horizontal axis perpendicular to and intersecting said screw axis to move said material gripping surface of said jaw upwardly and downwardly in said slot, said material gripping surface of said jaw being arcuately convex in a vertical plane, said jaw having a horizontal initial position at which said arcuate gripping surface extends furthest into said slot at a point along said first horizontal axis and recedes horizontally from said point uniformly above and below said first horizontal axis, said radius of curvature being greater than the horizontal distance between said jaw pivotal axis and said material gripping surface of said jaw when said jaw is horizontal, so that the jaw teeth bite into the material when said jaw is pivoted downwardly by the weight of the material upon application of a lifting force to the shackle; and resilient means connected between said clamp body and said pivotable jaw to resiliently urge said pivotable jaw in both rotational directions toward said horizontal initial position to cause said pivotable jaw to assume said horizontal initial position when not in contact with material to be lifted and to resist rotation of said pivotable jaw in either direction from said horizontal initial position.