|Patent 1,373,112 · Backus's Check Lock · Page 2|
|suitable sheet metal blank and is substantially channel shaped, the side flanges of the hook extending from end to end thereof. As its inner end the hook is secured to the back plate 10 of the casing, rivets or other suitable fastening devices being engaged through said plate and through the bottom web of the hook for firmly securing the hook in position depending from the casing. At its outer end the hook is formed with a vertically disposed tip 29 and the side flanges thereof are, as shown in detail in Fig. 4, provided with notches 30 defining shoulders 31 at their lower ends. Mounted upon the outer end of the hook is a longitudinally curved head 32. This head is also pressed from a suitable sheet metal blank and, like the hook, is substantially channel shaped in cross section. Toward the center of the head the side flanges thereof are gradually widened and medially of said head the innermost side flange thereof is provided with a notch 33 while in the outermost side flange of the head are formed, opposite the notch, spaced slots 34. The major width of the head is substantially equal to the major depth of the hook at its outer end so that the head may be fitted upon the hook to extend transversely thereof, the notch 33 snugly receiving the outer end portion of the hook therethrough so that the tip 29 projects between the side flanges of the head. The bottom wall of the notch 33 seats against the upper face of the hook while the shoulders 31 project through the slots 34 seating against the bottom walls of said slots so that the vertical walls of the notches 30 thus confront the inner face of the outermost flange of the head. As will thus be seen, the side flanges of the head will sustain said head upon the hook while said flanges will also coöperate with the hook for holding the head against transverse movement toward and away from the casing. Engaged through the head flanges and through the tip 29 of the hook is a rivet or other approved fastening device 35 firmly securing the head in position. Swingingly mounted upon the hook to extend transversely across the bight thereof is a latch 36. This latch is also pressed from a suitable sheet metal blank and is substantially chanel shaped in cross section. At the inner end of the body of the latch, the side flanges thereof are extended to provide longitudinally curved arms 37 embracing the shank of the hook 28 immediately below the lower end of the casing and extending through said arms and through the hook flanges is a pivot pin 38 swingingly connecting the latch with the hook. At the outer end portion of the latch body the side flanges thereof are, as particularly shown in Fig. 2, widened somewhat, and are formed with inwardly and downwardly sloping edges 39||
normally resting against the upper convex face of the head 32 and
at their inner ends, defining shoulders 40 lying close to the inner
side face of the head. At the outer ends of the flanges of the latch,
the body wall or web thereof is extended to form a laterally flared
end plate 41 which is bent downwardly to abut said flanges so that
the ends of said plate project laterally at opposite sides of the
latch providing ears 42 which may be grasped for lifting the latch.
Mounted to coact with the latch 36 is a substantially U-shaped lock bolt 43. This lock bolt, like the hook 28 and latch 36, is also pressed from a suitable sheet metal blank and, as shown in Fig. 5, is substantially T-shaped in cross section, the intermediate portion of the blank being pressed up in overlapping relation to provide a medial longitudinal rib 44 from which extend in opposite direction lateral side flanges. As will be observed, the rib extends from the inner end of the bolt to a point near its outer end, the outer arm of the bolt being flared laterally at the adjacent end of said rib to form a bead 45 having a concave lower edge adapted to fit the slightly convex body wall of the latch 36. The arms of the bolt are substantially parallel and the inner arm thereof is slidably received through suitable openings in the top and bottom flanges 11 of the base plate 10 of the casing, being retained by the cap plate 14 so that, as will be seen, the bolt is thus slidably mounted upon the casing for movement toward and away from the latch. As shown in Fig. 2 the inner arm of the lock bolt is somewhat longer than the outer arm thereof so that the lock bolt may be depressed to engage the head 45 of the outer arm with the latch at a point spaced laterally at the outer side of the plane of the head 32 of the hook while the inner arm of the bolt will be projected through the latch lying between the arms 37 of the latch and closely confronting the inner edge of the body wall or web thereof. The bolt will thus effectively lock the latch against upward swinging movement while the concave lower edge of the head will coact with the convex body wall or web of the latch for securing the latch against being forcibly moved laterally from beneath the head. However, to additionally lock the latch against lateral movement, the inner arm of the lock bolt is, as previously explained, caused to project through the latch so that, as will be seen, the lower end of said arm will be disposed to coact with the arms 37 of the latch for preventing distortion of the latch and its displacement from beneath the head 45.
Struck from one of the side flanges of the lock bolt at a point along the inner arm thereof is an eye 46 through which the link