Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16B—DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING
  • F16B13/00—Dowels or other devices fastened in walls or the like by inserting them in holes made therein for that purpose
  • F16B13/04—Dowels or other devices fastened in walls or the like by inserting them in holes made therein for that purpose with parts gripping in the hole or behind the reverse side of the wall after inserting from the front
  • F16B13/06—Dowels or other devices fastened in walls or the like by inserting them in holes made therein for that purpose with parts gripping in the hole or behind the reverse side of the wall after inserting from the front combined with expanding sleeve
  • F16B13/061—Dowels or other devices fastened in walls or the like by inserting them in holes made therein for that purpose with parts gripping in the hole or behind the reverse side of the wall after inserting from the front combined with expanding sleeve of the buckling type

Definitions

• the present invention relates to a wall plug, in particular but not exclusively a wall plug for mounting in a cavity wall.
• Cavity walls are commonly constructed using plasterboard to form at least one face of the wall.
• Plasterboard has a known thickness (typically about 12 mm).
• Wall plugs for securance to plasterboard usually have a body part for location in a bore formed in the plasterboard and an anchorage part which projects beyond the inner side of the plasterboard.
• the screw ixing engages within the anchorage part; on rotation of the screw fixing, the anchorage part is moved axially toward the inner side of the plasterboard and the such movement is utilised to cause the anchorage part to expand the wall plug to engage against the inner side of the plasterboard.
• This type of wall plug is usually made of plastics and usually in one piece. For the designed expansion to occur on axial displacement of the anchorage part, it is necessary for the anchorage part to move axially without twisting about its axis.
• the anchorage part is normally provided with a smooth walled bore into which the screw fixing extends. On rotation of the screw fixing, it bites into the wall of the bore and in so doing cuts a screw thread and moves the anchorage part axially.
• the action of the screw fixing cutting a screw thread is highly desirable to provide a relatively strong resistance to axial withdrawal of the screw fixing by a pulling force but unfortunately the cutting action has a tendency to cause the anchorage part to twist. If twisting happens, the designed expansion of the wall plug is not achieved.
• a wall plug comprising a body part of generally cylindrical form and an anchorage part projecting from one axial end of the body part, the body part and anchorage part being integrally moulded from a plastics material, the body part having an axially extending bore for receiving a screw fixing and the anchorage part having an axially extending passageway axially aligned with the bore of the body part, said passageway including internally projecting screw thread formations with which a screw fixing extending along the passageway can screw threadingly engage.
• FIG. 1 is a perspective view from above of a wall plug according to one embodiment of the invention
• Figure 2 is a perspective view from below of the wall plug shown in Figure 1
• Figure 3 is an axial section through the plug of Figure 1 located in a wall
• Figure 4 is an axial section similar to Figure 3 showing a screw fixing located in the plug
• Figure 5 is a side view of a wall plug according to another embodiment of the invention
• Figure 6 is an axial section along the wall plug of Figure 5.
• a wall plug according to an embodiment of the present invention is generally shown at 10 and includes a body part 12 and an anchorage part 14.
• the body part 12 and anchorage part 14 are joined together by a pair of wing formations 16.
• the body part 12, anchorage part 14 and wing formations 16 are integrally formed by injection moulding of a suitable plastics material, such as polypropylene, in order to define a one piece wall plug 10.
• the body part 12 is of generally cylindrical form having a central bore 18 passing therethrough.
• the axial extent of the body part 12 is substantially the same as the thickness W ⁇ of the wall, W, such as plasterboard, in which the plug is to be mounted. Accordingly, when mounted in such a plasterboard wall, the body part 12 is located in a bore formed in the plasterboard and the wing formations 16 and anchorage part 14 project beyond the inner face Wi of the plasterboard wall W (see Figure 3).
• the anchorage part 14 includes an axially extending passageway 20 which is axially aligned with the central bore 18.
• a screw fixing 30 having a head 31 and a screw threaded shank 32 (having screw threads 33) is inserted into the bore 18. Rotation of fixing 30 causes it to pass through the bore 18 and eventually enter into the passageway 20 of the anchor part 14. Continued rotation of the fixing 30 will cause the fixing to continue to move axially into the plug 10 until its head 31 abuts the outer face W 0 of the wall W.
• plug 10 is firmly prevented from being pulled axially outwardly from the wall W by a combination of (i) radially outward pressure applied by the body part 12 against the surrounding wall of the bore in which it is received and (ii) the abutment of the wing formations 16 against the inner wall face Wi.
• the screw fixing 30 is prevented from being pulled axially (without rotation) from the wall plug 10 primarily due to the interaction of the screw threads 33 of the screw fixing 30 with the surrounding wall of the passageway 20.
• the interior of the passageway with a plurality of inwardly directed projections 50 which are spaced axially along the passageway 20.
• the projections 50 collectively act as an internal screw thread formation with which the external screw thread 33 of the screw fixing 30 can threadingly engage.
• the projections 50 may be formed by a series of discontinuous part screw thread portions in the form of continuous ridges 51, each of which may be a continuous rib or a series of spaced discrete projections which collectively define a ridge.
• the anchorage part 14 is formed to define the passageway 20 as a pair of open topped channels 35, the bottom and sides of each channel preferably being provided with a plurality of projections 50 and the open top defining a window to enable the projections 50 to be injection moulded with the remainder of the body of the anchorage part 14.
• a second embodiment 100 is illustrated in Figures 5 and 6 wherein parts similar to those in Figures 1 to 4 have been designated using the same reference numerals.
• the wall plug 100 has an anchorage part 14 which is of generally cylindrical form having passageway 20 passing axially therethrough.
• the passageway 20 is defined by four open topped channels 35 containing screw threaded formations 50.
• the body part 12 is provided with a generally V-shaped slot 60 which is axially opposed to an inner axial end 61 of the anchorage part 14.
• the body part 12 and anchorage part 14 are connected together by short arms 63 extending between the opposed walls of axial end 61 and axial end faces of slot 60.
• a screw fixing 30 is inserted into wall plug 100 and rotated. When the head 31 of the screw fixing abuts the outer axial end of the body part 12, continued rotation of the screw fixing causes the anchorage part 14 to move axially toward the body part 12 and such movement causes arms 63 to collapse and cam faxes 25 on the axial end 61 thereby cause the body part 12 to be expanded in a radial direction.

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• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Dowels (AREA)

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• 2003
  • 2003-08-07 GB GB0318618A patent/GB0318618D0/en not_active Ceased
• 2004
  • 2004-08-06 EP EP04743659A patent/EP1651874A1/de not_active Withdrawn
  • 2004-08-06 WO PCT/GB2004/003371 patent/WO2005015033A1/en active Search and Examination

Non-Patent Citations (1)

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