GB618289A - Improvements in or relating to gully traps and covers therefor - Google Patents

Abstract

618,289. Gulley trap covers. HAMMOND, J. Oct. 11, 1946, No. 30375. [Class 33] In a gulley trap A of the kind used in the external drainage systems for buildings, the cover C thereof comprises an apertured plate which is flexible in a direction normal to its surface and is secured in position by its resistance to such flexure or by residual reflex stresses, said resistance or residual stresses being such that the cover cannot easily be removed from its seating D without the use of a tool designed for the purpose. In the form shown, the cover is circular with a bevelled edge F to engage a complementary V-shaped groove forming the seating D, radial or concentric rows of perforations E, one or more radial stiffening projections on its underside, and a central dependant boss G with a diametrically arranged slot H and downwardly facing recesses I at opposite sides thereof. The cover is made of natural rubber, oil-resisting synthetic rubber, or like material that can be flexed into part spherical shape. A tool for this purpose may comprise a' ring N to bear upon the cover, radiating arms O, a bush P, spaced cheeks V to engage the sides of fork limbs 5 of an actuating lever M which is pivoted at T to a stem L guided in the bush P and formed at its lower end with a T-shaped head Q adapted to pass through the slot H and engage the recesses I. The fork limbs S have identical cam profiles U to engage the upper end of the bush P so that, on raising the lever M, the stem L is lifted and the cover C is flexed into part spherical shape whereby it may be inserted into, or removed from, the groove D.