Self-drilling toggle fastener

Abstract: A fastener (10) mountable in a plasterboard wall (20) from one side of the wall and used with a screw comprises a fastener body (40) and a toggle clamp (42) pivotable between an insertion position and a toggle position. The fastener (10) has a drilling tip (50) adapted to drill a hole of sufficient diameter to accommodate the fastener (10), except for its head (44), which is arranged to coact with a driving tool. In a first embodiment, the drilling tip (50) is an integral part of the fastener body (40) and extends axially beyond the toggle clamp (42) in its insertion position. In a second embodiment, the drilling tip is an integral part of the toggle clamp and extends axially beyond the fastener body in the insertion position of the toggle clamp. In each embodiment, the fastener (10) is self-drilling.

Description: This invention relates to an improved fastener including a toggle clamp and being capable of being mounted in a plasterboard or similar wall from one side only of the wall (US-A-4 047 462). A plasterboard wall comprises a core of friable material, such as gypsum plaster, between two paper layers. It is difficult to mount a heavy object to such a wall. The core easily crumbles and the paper layers are easily torn. Commonly, a blind fastener of a type including a toggle clamp is used to mount an object to a plasterboard or similar wall. A blind fastener is a fastener capable of being mounted to a wall from one side of the wall. Self-drilling fasteners are well known for insertion into harder, less friable materials such as concrete and stone. Such a fastener is shown in DE-A-2,945,663 which discloses a self-drilling anchor which forms a hole in a hard material, and is then expanded to grip the sides of the hole. Such a fastener is totally unsuitable for friable material such as plasterboard, firstly the plasterboard will be destroyed by the insertion of fastener, and secondly a secure fixing in plasterboard cannot be achieved by expanding the fastener radially to contact the inside walls of a hole. According to this invention a fastener capable of being drilled into a friable wall such as plasterboard, and of being used with a screw having a head and an elongate shank with a threaded portion, the fastener comprising: (a) a fastener body defining an axis and having a head, a shank integral with and extending axially from the head, and at least one elongate arm integral with and extending axially from the shank, the fastener body having an axial bore, which extends through the head and shank, and which is, in use, arranged to permit the shank of a screw to be screwed into it; (b) a toggle clamp pivotally mounted on the fastener body between an insertion position wherein the toggle clamp is aligned generally with the axis and a toggle position wherein the toggle clamp is disposed generally at right angles to the axis, and so as to permit axial movement of the toggle clamp relative to the fastener body, the toggle clamp having a thread-accepting aperture, which is, in use, arranged to form a threaded connection with the threaded portion of the shank of the screw and to effect axial movement of the toggle clamp relative to the fastener body as the screw is driven into the thread-accepting aperture and the toggle clamp has pivoted into the toggle position; (c) a threaded section formed on the shank (46) near the head (32), the threaded section having a thread (56, 156) for restricting rotational movement of the fastener body (40) relative to the wall when mounted in the wall; wherein the fastener has a drilling tip adapted to drill a hole to accommodate the fastener, when the toggle clamp is in the insertion position. Preferably, the toggle clamp has a ramp. In the insertion position of the toggle clamp, the ramp is arranged to be axially engaged by the screw, as the shank of the screw is driven into the bore, to pivot the toggle clamp from the insertion position into the toggle position. Preferably, the body includes a pair of arms and each of the arms has an axially extending slot and the toggle clamp has a pair of oppositely extending pintles. Each pintle extends into a respective one of the slots so as to mount the toggle clamp pivotally to the fastener body in such manner that the toggle clamp is disposed between the arms when the toggle clamp is in the insertion position. The slots and pintles permit axial movement of the toggle clamp relative to the fastener body. It is preferred that the fastener body includes means for restricting rotational movement of the fastener body relative to a wall when the fastener is mounted to the wall. Preferably, such means comprises a threaded section formed on the shank of the fastener body, near the head of the fastener body. The threaded section has a thread with a profile suitable for a wall comprising a friable material, as exemplified by a plasterboard wall. In a first embodiment, the drilling tip is an integral part of the fastener body. Specifically, the drilling tip is integral with the elongate arms and extends axially beyond the toggle clamp in both positions of the toggle clamp. In a second embodiment, the drilling tip is an integral part of the toggle clamp. Specifically, the drilling tip is integral with one of two opposite ends of the toggle clamp and extends axially beyond the arms of the fastener body in the insertion position of the toggle clamp. Preferably, the drilling tip has a central cutter and two outer cutters with a cavity between each of the outer cutters and the central cutter. Preferably, the central cutter extends beyond the outer cutters, each of which defines a helical cutting edge. In the first embodiment, the fastener body may include a deformable or frangible structure for preventing the toggle clamp from pivoting freely from the insertion position into the toggle position in a given direction of pivotal movement. Such structure is adapted to be deformed when engaged by the screw, as the shank of the screw is moved into the bore, so as to permit pivotal movement of the toggle clamp from the insertion position into the toggle position in the given direction. The deformable or frangible structure is adapted to prevent axial movement of the toggle clamp relative to the fastener body before the structure is deformed. Along with the deformable or frangible structure noted above, the fastener body may be also formed so as to include additional structure for preventing pivotal movement of the toggle clamp from the insertion position into the toggle position in the opposite direction of pivotal movement. Preferably, the additional structure extends between the arms in axially spaced relation to the shank of the fastener body. In the second embodiment, if the toggle clamp has a ramp as noted above, the fastener body and the toggle clamp may be then made so as to have coacting means for providing a driving connection between the fastener body and the toggle clamp when the toggle clamp is in the insertion position. The driving connection enables the fastener to be rotatably and axially driven without imparting substantial stress to the pintles when the drilling tip is used to drill a hole in a wall. The driving connection is releasable when the ramp is engaged by the screw so as to permit pivotal movement of the toggle clamp from the insertion position into the toggle position. Preferably, the coacting means include a non-circular plug formed on the toggle clamp and wall portions defining a socket in the fastener body. The plug is formed on the toggle clamp end opposite to the drilling tip. The socket conforms generally to the plug. The socket is adapted to receive the plug when the toggle clamp is in the insertion position. The socket is adapted to release the plug when the ramp is engaged by the screw so as to permit pivotal movement of the toggle clamp from the insertion position into the toggle position. Preferably, moreover, the ramp is defined by a groove formed in the plug. Embodiments of fasteners in accordance with this invention will now be described with reference to the accompanying drawings; in which:- Figure 1 is a sectional side elevation taken through a fragmentary portion of a plasterboard wall to show a fastener according to a first embodiment after it has been inserted through a hole drilled through the plasterboard wall by means of its drilling tip; Figure 2 is a sectional view taken along line 2--2 of Figure 1, in a direction indicated by arrows, to show the fastener in cross-section; Figure 3 is a view similar to Figure 2 but taken to show a screw being used to mount a fixture to the plasterboard wall and beginning to coact with the fastener with the fastener, the screw, and the fixture being shown fragmentarily; Figure 4 is a similar view showing the screw as having coacted with the fastener so as to pivot a toggle clamp into a toggle position and so as to draw the toggle clamp against the plasterboard wall; Figure 5 is an elevational view showing the fastener in end elevation without the screw and without the fixture; Figure 6 is a sectional view taken along line 6--6 of Figure 1, in a direction indicated by arrows, to show certain details of the fastener; Figure 7, on a slightly enlarged scale, is a fragmentary, perspective view of a drilling tip on the fastener; Figure 8, on the original scale, is an end view taken along line 8--8 of Figure 7, in a direction indicated by arrows; Figure 9 is a sectional view taken through a fragmentary portion of a plasterboard wall to show a fastener according to a second embodiment with the fastener being shown in side elevation as about to drill a hole through the plasterboard wall by means of its drilling tip on the fastener with a screwdriver being shown fragmentarily; Figure 10 is a view similar to Figure 9 but taken to show the fastener as inserted through the hole drilled through the plasterboard wall; Figure 11 is a sectional view taken along line 11--11 of Figure 10, in a direction indicated by arrows, to show certain details of the fastener; Figure 12 is a view similar to Figure 10 but taken in a changed position to show a screw being used to mount a fixture to the plasterboard wall and beginning to coact with the fastener, the screw and the fixture being shown fragmentarily; Figure 13 is a sectional view taken along line 13--13 of Figure 12, in a direction indicated by arrows, to show certain details of the fastener and the screw coacting with the fastener; Figure 14 is an exploded, fragmentary, perspective view showing certain details of a driving connection of the embodiment shown in Figures 9 et seq; Figure 15 is a sectional view taken along line 15--15 in Figure 10, in a direction indicated by arrows, to show certain details of the driving connection; Figure 16 is a sectional view similar to Figure 13 but taken to show the fastener, the screw, and the fixture at a later stage in mounting the fixture to the plasterboard wall; and, Figure 17 is a view similar to Figures 13 and 16 but taken to show the fastener in side elevation and the screw as having coacted with the fastener so as to pivot a toggle clamp into a toggle position, and so as to draw the toggle clamp against the plasterboard wall, at a final stage in mounting the fixture to the plasterboard wall. Because an improved fastener according to this invention is self-drilling, such a fastener may be advantageously used with a plasterboard wall having a core of friable material, such as gypsum plaster, between two paper layers. Moreover, such a fastener may be alternatively used with a plaster wall or with a wall made predominately of wood, presswood, or like material. An improved fastener according to this invention is designed to coact with a conventional screw having a head designed to act with a conventional driving tool, such as a Phillips screwdriver, an elongated shank with a threaded portion, and a tip. The tip may be pointed or blunt. A pointed tip is preferred. As shown in Figures 1 through 8, a fastener 10 constitutes a first of the preferred embodiments of this invention. The fastener 10 is shown as used to mount a fixture 12 to a plasterboard wall 20. The wall 20 has a core 22 of friable material, such as gypsum plaster, between two paper layers, namely an outer layer 24 and an inner layer 26. As shown, a hole 28 accommodating the fastener 10 is drilled, via the fastener 10, through the wall 20. As explained below, the fastener 10 is used to drill such a hole. The fastener 10 is shown as coacting with a conventional screw 30 having a Phillips head 32, an elongate shank 34 with a threaded portion 36, and a pointed tip 38. The Phillips head 32, which is designed to coact with a conventional Phillips screwdriver, retains the fixture 12 when the screw 30 is driven into the fastener 10. Broadly, the fastener 10 comprises a fastener body 40 and a toggle clamp 42. Preferably, the fastener body 40 is die-cast from zinc and the toggle clamp 42 is stamped from sheet metal. Although zinc die-castings and sheet metal stampings are preferred, it is possible to mold the fastener body 40 and the toggle clamp 42 from a suitable plastic, such as reinforced polyolefin. As die-cast or molded, the fastener body 40 defines an axis and has a head 44, a shank 46, a pair of elongate arms 48, and a drilling tip 50. As compared to the shank 46, which has a relatively small cross section, the head has a relatively large cross section. Also, the head 44 is provided with a socket 52, by which the head 44 is adapted to coact with a conventional Phillips screwdriver. The fastener body 40 includes means for restricting rotational movement of the fastener body 40 relative to a wall, such as the wall 20, when the fastener 10 is mounted to the wall. Thus, the shank 46 has a threaded section 54 near the head 44. The threaded section 54 has a thread 56 with a profile suitable for a wall, such as the plasterboard wall 20, which comprises a friable material. The elongate arms 48 are integral with the shank 46 and extend axially from the shank 46. The arms 48 fit within an imaginary, cylindrical envelope having a cross section equal approximately to the cross section of the threaded section 54, except for the thread 56. The fastener body 40 has an unthreaded, axial bore 58, which extends through the head 44 and the shank 46, and which opens between the arms 48. The bore 58 is arranged to permit the shank 34 of the screw 30 to be axially moved into the bore 58. The shank 34 of the screw 30 may be axially pressed or rotatably and axially driven into the bore 58. As an integral part of the fastener body 40, the drilling tip 50 is integral with the elongate arms 48, which are spanned by the drilling tip 50. As shown in Figures 6 through 8, the drill tip 50 comprises a thin blade 60, which defines a centre cutter 62, and two outer cutters 64 with a cavity 66 between each of the outer cutters 64 and the central cutter 62. The central cutter 62, which extends axially beyond the outer cutters 64, is wedge-shaped, as shown. Each outer cutter 64 defines a helical cutting edge 68. When the drilling tip 50 is used to drill a hole, such as the hole 28, the central cutter 62 penetrates the outer, paper layer 24 and the core 22 before the outer cutters 64 contact such layer 24. Thereupon, the helical cutting edges 68 of the outer cutters 64 cut cleanly through the outer, paper layer 24 with minimal risk of tearing such layer 24. The toggle clamp 42 is mounted to the fastener body 40 so as to permit pivotal movement of the toggle clamp 42 relative to the fastener body 40 between an insertion position and a toggle position, and so as to permit axial movement of the toggle clamp 42 relative to the fastener body 40. In the insertion position, in which the toggle clamp 42 is shown in Figures 1, 2 and 3, the toggle clamp 42 is aligned generally with the elongate arms 48. In the toggle position, in which the toggle clamp 42 is shown in Figure 4, the toggle clamp 42 is disposed generally at a right angle to the elongate arms 48. As explained below, the screw 30 is used to pivot the toggle clamp 42 from the insertion position into the toggle position, after the fastener 10 has been inserted into the hole 28 with the toggle clamp 42 in the insertion position. Each arm 48 has an axially extending slot 70. The toggle clamp 42 has a pair of oppositely extending pintles 72. Each pintle 72 extends into a respective one of the slots 70 so as to mount the toggle clamp 42 pivotally to the fastener body 40 in such manner that the toggle clamp 42 is disposed between the arms 48 when the toggle clamp 42 is in the insertion position. The slots 70 and pintles 72 permit axial movement of the toggle clamp 42 relative to the fastener body 40. The toggle clamp 42 has a ramp 74, which is inclined, as shown, so as to define an angle of about 45° relative to the axis defined by the fastener body 40 when the toggle clamp 42 is in the insertion position. Thus, in the insertion position of the toggle clamp 42, the ramp 74 is arranged to be axially engaged by the tip 38 of the screw 30 as the shank 34 of the screw 30 is moved into the bore 58 of the fastener body 40. The toggle clamp 42 has a thread-accepting aperture 76, which is adapted to form a threaded connection with the threaded portion 36 of the shank 34 of the screw 30, when the screw 30 is driven into the thread-accepting aperture 76, after the toggle clamp 42 has been pivoted into the toggle position. As shown, the threaded portion 36 is threaded into the toggle clamp 42. Alternatively, the thread-accepting aperture 76 may be complementarily threaded, so as to coact with the threaded portion 36. The toggle clamp 42 has a flange 78 near the thread-accepting aperture 76. The flange 78 is shaped so as to help to guide the threaded portion 36 of the shank 34 of the screw 30 into the thread-accepting aperture, as shown in Figure 4, in the toggle position of the toggle clamp 42. As die-cast or molded, the fastener body 40 has a deformable tongue 80, which serves as means for preventing the toggle clamp 42 from pivoting freely from the insertion position into the toggle position in a given direction of pivotal movement. In Figures 2, 3, and 4, the given direction of pivotal movement is clockwise. The tongue 80 includes a lip 81 adapted to be engaged by the tip 38 of the screw 30, as the shank 34 of the screw 30 is moved into the bore 58, so as to break away, thereby to permit pivotal movement of the toggle clamp 42 from the insertion position into the toggle position in the given direction. It is not necessary, however, for the tongue 80 to break away so as to permit such movement. The tongue 80 is formed with an internally extending tab 82. The tab 82 fits into an aperture 84 in the toggle clamp 42 and coacts with the aperture 84, so as to prevent axial movement of the toggle clamp 42 relative to the fastener body 40 before the tongue 82 is deformed. A connecting bridge 90 is formed integrally with the arms 48, so as to extend between the arms 48, in axially spaced relation to the shank 46. The bridge 90 constitutes means for preventing pivotal movement of the toggle clamp 42 from the insertion position into the toggle position in an opposite direction of pivotal movement. In Figures 2, 3, and 4, the opposite direction of pivotal movement is counterclockwise. As shown in Figures 9 through 17, a fastener 110 constitutes a second of the preferred embodiments of this invention. The fastener 110 is a blind fastener, which is capable of mounting a fixture 112 to a plasterboard wall 120. The plasterboard wall 120 is similar to the wall 20 and comprises a core 122 of friable material, such as gypsum plaster, between two paper layers, namely an outer layer 124 and an inner layer 126. As shown in Figures 10, 12, and 13, a hole 128 accommodating the fastener 110 is drilled through the wall 120. As explained below, the fastener 110 is used to drill such a hole. The fastener 110 is shown as coacting with a conventional screw 130 similar to the screw 30 described above. Thus, the screw 130 has a Phillips head 132, an elongate shank 134 with a threaded portion 136, and a pointed tip 138. The head 132 retains the fixture 112, as shown, when the screw 130 is driven into the fastener 110. Broadly, the fastener 110 comprises a fastener body 140 and a toggle clamp 142. Preferably, the fastener body 140 and the toggle clamp 142 are molded from a suitable plastic, such as reinforced polyolefin. Although plastic moldings are preferred, it is possible to die-cast the fastener body 140 from zinc and to stamp the toggle clamp 142 from sheet metal. As molded or die-cast, the fastener body 140 defines an axis and has a head 144, a shank 146, a pair of elongate arms 148, and a connecting bridge 150. As compared to the shank 146, which has a relatively small cross section, the head 144 has a relatively large cross section. Also, the head 144 is provided with a socket (not shown) which is similar to the socket 52 of the head 44 of the screw 30, and by which the head 144 is adapted to coact with a conventional Phillips screwdriver, such as the Phillips screwdriver D shown fragmentarily in Figures 9 and 10. The fastener body 140 includes means for restricting rotational movement of the fastener body 140 relative to a wall, such as the wall 120, when the fastener 110 is mounted to the wall. Thus, the shank 146 has a threaded section 154 near the head 144. The threaded section 154 has a thread 156 with a profile suitable for a wall such as the plasterboard wall 120, which comprises a friable material. The elongate arms 148 are integral with the shank 146 and extend axially from the shank 146. The arms 148 fit within an imaginary, cylindrical envelope having a cross section equal approximately to the cross section of the threaded section 154, except for the thread 156. The bridge 150, which is integral with the arms 148, connects the arms 148 at their distal ends, in axially spaced relation to the threaded section 154. The fastener body 140 has an unthreaded, axial bore 158, which extends through the head 144 and the shank 146, and which opens between the arms 148. The bore 158 is arranged to permit the shank 134 of the screw 130 to be axially moved into the bore 158. The shank 134 may be axially pressed or rotatably and axially driven into the bore 158. The toggle clamp 142 is mounted to the fastener body 140 so as to permit pivotal movement of the toggle clamp 142 relative to the fastener body 140 between an insertion position and a toggle position, and so as to permit axial movement of the toggle clamp 142 relative to the fastener body 140. In the insertion position, in which the toggle clamp 142 is shown in Figures 9 through 12, the toggle clamp 142 is aligned generally with the elongate arms 148. In the toggle position, in which the toggle clamp 142 is shown in Figures 16 and 17, the toggle clamp 142 is disposed generally at a right angle to the elongate arms 148. As explained below, the screw 130 is used to pivot the toggle clamp 142 from the insertion position into the toggle position, after the fastener 110 has been inserted into the hole 128 with the toggle clamp 142 in the insertion position. Each arm 148 has an axial extending slot 170. The toggle clamp 142 has a pair of oppositely extending pintles 172. Each pintle 172 extends into a respective one of the slots 170 so as to mount the toggle clamp 142 pivotally to the fastener body 140 in such manner that the toggle clamp 142 is disposed between the arms 148 when the toggle clamp 142 is in the insertion position. The slots 170 and pintles 172 permit axial movement of the toggle clamp 142 relative to the fastener body 140. The toggle clamp 142 has a ramp 174. In the insertion position of the toggle clamp 142, the ramp 174 is arranged to be axially engaged by the tip 138 of the screw 130 as the shank 134 of the screw 130 is pressed into the bore 158 of the fastener body 140. The toggle clamp 142 has a thread-accepting aperture 176, which is adapted to form a threaded connection with the threaded portion 136 of the shank 134 of the screw 130, when the screw 130 is driven into the thread-accepting aperture 176, after the toggle clamp 142 has been pivoted into the toggle position. As shown, the thread-accepting aperture 176 is threaded complementarily, so as to coact with the threaded portion 136. As fabricated, the toggle clamp 142 is formed on one of its ends with an integral drilling tip 180. As shown, the drilling tip 180 comprises a thin blade 182 defining three wedge-shaped cutters, namely a central cutter 184 and two outer cutters 186 with a cavity 188 between each of the outer cutters 186 and the central cutter 184. The central cutter 184 extends axially beyond the outer cutters 186. When the drilling tip 180 is used to drill a hole, such as the hole 128, the central cutter 184 penetrates the outer, paper layer 124, as shown in Figure 9, before the outer cutters 186 contact such layer 124. Thereupon, the outer cutters 186 cut through the outer, paper layer 124. In an alternative arrangement (not shown) the toggle clamp 142 may be integrally formed with a drilling tip similar to the drilling tip 50 of the first embodiment described above. Such a drilling tip may be more effective, as it tends to cut clearly through an outer, paper layer of a plasterboard wall with minimal risk of tearing such layer. The fastener body 140 and the toggle clamp 142 have a driving connection therebetween when the toggle clamp 142 is in the insertion position. The driving connection enables the fastener 110 to be rotatably and axially driven without imparting substantial stress to the pintles 172 when the drilling tip 180 on the toggle clamp 142 is used to drill a hole, such as the hole 128, in a wall, such as the wall 120. The driving connection is releasable when the ramp 174 is engaged by the screw 130 so as to permit pivotal movement of the toggle clamp 142 from the insertion position into the toggle position. The driving connection is defined by a non-circular plug 190 formed on one end of the toggle clamp 142, namely the end opposite to the drilling tip 180, and a socket 192 formed in the fastener body 140. The plug 190 and the socket 192 have non-circular cross-sections. The socket 192 conforms generally to the plug 90. As shown, the plug 190 is substantially square in cross-section and is formed with the ramp 174, which is defined by a groove formed in the plug 190. As shown, the socket 192 is substantially square in cross-section and with one open side and is defined by wall portions 194, 196, 198, which enclose the plug 190 on three sides when the toggle clamp 142 in the insertion position is pressed axially against the shank 146 of the fastener body 140. Thus, the socket 192 is adapted to receive the plug 190 when the toggle clamp 142 is in the insertion position. The wall portion 196 bridges the wall portions 194, 198, and extends axially for a short distance, as shown. Thus, the socket 192 is adapted to release the plug 192 when the toggle clamp 142 is displaced axially by a greater distance, after the ramp 174 has been engaged by the screw 130, so as to release the driving connection between the fastener body 140 and the toggle clamp 142.

Claims: A fastener (10) capable of being drilled into a friable wall such as plasterboard and of being used with a screw (30) having a head (32) and an elongate shank (34) with a threaded portion, the fastener comprising: (a) a fastener body (40) defining an axis and having a head (44), a shank (46) integral with and extending axially from the head (44) and at least one elongate arm (48) integral with and extending axially from the shank (46), the fastener body (40) having an axial bore (58), which extends through the head (44) and shank (46), and which is, in use, arranged to permit the shank (34) of a screw (30) to be screwed into it; (b) a toggle clamp (42) pivotally mounted on the fastener body (40) between an insertion position wherein the toggle clamp (42) is aligned generally with the axis and a toggle position wherein the toggle clamp (42) is disposed generally at right angles to the axis, and so as to permit axial movement of the toggle clamp (42) relative to the fastener body (40), the toggle clamp (42) having a thread-accepting aperture (76), which is, in use, arranged to form a threaded connection with the threaded portion (36) of the shank (34) of the screw (30) and to effect axial movement of the toggle clamp (42) relative to the fastener body (40) as the screw is driven into the thread-accepting aperture (76) and the toggle clamp (42) has pivoted into the toggle position; and (c) a threaded section formed on the shank (46) near the head (32), the threaded section having a thread (56, 156) for restricting rotational movement of the fastener body (40) relative to the wall when mounted in the wall; wherein the fastener (10) has a drilling tip (50) adapted to drill a hole to accommodate the fastener (10), when the toggle clamp (42) is in the insertion position. A fastener according to claim 1, wherein the toggle clamp (42) has a ramp (74), which in the insertion position of the toggle clamp (42) is arranged to be axially engaged by the screw (30), as the shank (34) of the screw (30) is driven into the bore (58), so as to pivot the toggle clamp (42) from the insertion position into the toggle position. A fastener according to claim 1 or 2, wherein a pair of elongate arms (48) is included and the drilling tip (80) is integral with the elongate arms (48) and extends axially beyond the toggle clamp (42) in both positions of the toggle clamp (42). A fastener according to any one of the preceding claims, wherein the fastener body (40) includes deformable means (80) for preventing the toggle clamp (42) from pivoting freely from the insertion position into the toggle position in one direction of pivotal movement, the means (80) being deformed, in use, as the shank (34) of the screw (30) is driven into the bore (58), to permit pivotal movement of the toggle clamp (42) from the insertion position into the toggle position in the one direction, and wherein the fastener body (40) includes additional means (90) for preventing pivotal movement of the toggle clamp (42) from the insertion position into the toggle position in an opposite direction of pivotal movement. A fastener according to claim 4, wherein the deformable means (80) includes a lip (81) engageable by the screw (30), as the shank of the screw is driven into the bore, to bend the deformable means (80) away from the fastener body (40). A fastener according to claim 1 or 2, wherein the fastener body (100) has two elongate arms (148), the toggle clamp (142) has two opposite ends, the drilling tip (180) being integral with one of the opposite ends of the toggle clamp (142) and extending axially beyond the arms (148) of the fastener body (140) in the insertion position of the toggle clamp (142). A fastener according to claim 6, wherein the fastener body (140) and the toggle clamp (142) have coacting means (190, 192) for providing a driving connection between the fastener body (140) and the toggle clamp (142), when the toggle clamp (142) is in the insertion position, the driving connection enabling the fastener to be rotatably and axially driven without imparting substantial stress to the pivotal connection between the fastener body (140) and the toggle clamp (142) when the drilling tip (180) is used to drill a hole in a wall, the driving connection being releasable when the ramp (174) is engaged by the screw (130) thereafter to permit pivotal movement of the toggle clamp (142) from the insertion position into the toggle position. A fastener according to claim 7, wherein the coacting means for providing the driving connection include a non-circular plug (190) formed on the toggle clamp (142) and wall portions (192) defining a socket in the fastener body (140), the plug (190) being formed on the end of toggle clamp (142) opposite to the drilling tip (180), the socket conforming generally to the plug and being adapted to receive the plug when the toggle clamp is in the insertion position and to release the plug when the ramp (174) is engaged by the screw thereafter to permit pivotal movement of the toggle clamp (142) form the insertion position into the toggle position. A fastener according to any one of claims 2 to 8, wherein each of the elongate arms (48, 148) has an elongate slot (70, 170) and the toggle clamp (42, 142) has a pair of oppositely extending pintles (72, 172), each of which extends into a respective one of the slots (70, 170) so as to mount the toggle clamp (42, 142) on to the fastener body (40, 140) so that the toggle clamp (42, 142) when in the insertion position is disposed between the arms (48, 148), and to permit axial movement of the toggle clamp (42, 142) relative to the fastener body. A fastener according to any one of the preceding claims, wherein the drilling tip (80, 180) has a central cutter (84, 184) and two outer cutters (86, 186) with a cavity (88, 89, 188, 189) between each of the outer cutters (86, 186) and the central cutter (84, 184), the centre cutter (84, 184) extending axially beyond the outer cutters (86, 186) and, each of the outer cutters (86, 186) defines a generally helical cutting edge (64). A fastener according to any one of the preceding claims, wherein the head (44, 144) of the fastener includes means (52, 152) drivingly engageable by a tool to drive the fastener into a wall.

Inventors: DEWEY GEORGE G, TENUTA RALPH D, DEWEY, GEORGE G., TENUTA, RALPH D.
Applicants: ILLINOIS TOOL WORKS, ILLINOIS TOOL WORKS INC.
Application year: 1991
Main classification: F16B13
IPC codes: F16B13