| 主权项 |
1. A concrete anchor for securing the lanyard of a workman's harness to a fixed position on a concrete surface wherein said concrete surface has a cylindrically shaped bore formed therein, said anchor comprising:
a substantially cylindrically shaped housing having a substantially cylindrically shaped outer wall and a substantially hollow interior, said housing having a length defined by a lower end and an upper end, the outer dimensions of said housing being such as to fit within said bore in said concrete surface; a first set of openings in said outer wall, said first set of openings being angularly spaced from each other but being located the same axial distance from said lower end of said housing; a first set of hard metal balls within said hollow interior of said housing, the number of balls being equal to the number of said first set of openings with one ball associated with each opening, the diameter of each ball being slightly greater than the size of said openings whereby a portion of each ball can pass through each opening but the entire ball can not pass therethrough; a second set of openings formed in said outer wall of said housing, said second set of openings being in axial alignment with each other but being angularly spaced from each other, said second set of openings being axially spaced from said first set of openings and a second set of hard metal balls associated with said second set of openings with one ball being positioned within each of said second openings; a first cone within said housing, said first cone being in contact with said first set of balls so as to be capable of moving them radially outwardly, said first cone being vertically moveable between a lower position whereby said first balls lie substantially within said housing and a plurality of vertical positions wherein said balls are forced radially outwardly so as to extend into said first set of openings; a second cone within said housing, said second cone being connected to said rod and being arranged to move said second set of balls outwardly as said rod is moved upwardly, said second cone being axially spaced from said first cone and being connected thereto by a screw thread; biasing means within said housing biasing said cone upwardly to bias said balls outwardly; a rod connected to the top of said first cone and extending upwardly through and out of said upper end of said cylinder, and a loop at the upper end of said rod to which said lanyard can be attached, whereby if a sufficient upward force is applied to said loop, said first cone is moved upwardly to force said first set of balls into said first openings. |
