Abstract:
The embodiment of the invention disclosed herein is directed to a screw assembly comprising a cylindrical shank having a thread formed therealong and a conical head formed at the trailing end of the shank with slot means formed in the head for receiving a driving tool. An annular flange is formed at the top of the conical head and cooperates with a conical washer to form an annular groove or undercut between the flange and paper surface of wallboard when the screw is driven home firmly to hold the wallboard to support studs or the like. When the screw assembly is fully driven home, it forms an outwardly diverging depression about the screw head with the top surface of the screw head beneath the surface of the wallboard. A quantity of topping compound is applied over the screw head into the diverging depression completely to cover the screw head from view. The annular groove formed by the flange and the conical washer allows a quantity of the topping compound to flow therein thus providing a more secure bond of the topping compound patch so that flaking and chipping will not occur.
Abstract:
A threaded bolt has an enlarged hexagonal auxiliary driving head and an outwardly adjoining smaller main driving head. The small driving head is dimensioned so that it will shear from the remainder of the bolt under an applied driving torque which approximates the seating torque of the bolt. Thus when the bolt is screwed into a workpiece by applying a driving tool to the small driving head, the small head shears from the bolt when the bolt is fully seated and tightened in an assembly under a tensile load approximating the design load of the bolt. The large hole is used in removing the fastener from the assembly.
Abstract:
A threaded fastener device is provided with a longitudinally uniform multi-lobular driving cross section characterized by a shearing zone where lobes are sheared off at a substantially predetermined value of applied torque employed for seating the fastener device. The portion of the lobes remaining is capable of sustaining sufficient torque for effecting removal of the seated fastener device. A driver, forming a torque control system with the fastener device, is constructed to engage only the aforementioned shearing zone for severing the lobes within such zone while leaving the aforementioned remaining portion which may be engaged by a second driver for removal of the said fastener device.
Abstract:
A locking screw arrangement and fastener member are disclosed which provide for predictability and control of the locking action attained. In addition, there is disclosed a novel type of locking thread configuration wherein the leading or following flank of one or more thread turns on the fastener are bulged outwardly in an axial direction, with the opposite flank depressed, whereby said bulged flank will engage the corresponding flank of the female member to produce flank-toflank interference. In order to obtain said predictability and control, said locking arrangement employs an internally threaded female member having a thread configuration formed within industry accepted tolerances, which female member is engaged with an externally threaded fastener having a construction which eliminates any variables due to the tolerance encountered in the thread form of the female member that adversely effect the locking action. In this regard, the threaded portion of the fastener includes a preparation section and a locking section, the thread turns and the preparation section being such as to reshape and size the internal thread of the female member upon engagement therewith, thereby eliminating the effect of dimensional variables that may be encountered. Therefore, upon subsequent engagement of said reshaped internal threads with the thread turns of the locking portion, a predetermined locking action will be obtained.