In accordance with a first aspect of this invention, there is provided a method of securing a fastener in a hole extending into one or more bodies from a near opening at one side of said one or more bodies, the fastener including a head and a dilatable shank connected to the head, the method including arranging the fastener in the hole such that the head is offered to a surface around the near opening, the shank extends into the hole; applying compressive stress to the dilatable shank to dilate it to abut a surface around the hole by pulling on the dilatable shank via a pulling element extending through the hole and beyond the near opening; and anchoring the pulling element.

In a preferred method the pulling element may be pulled through a passage through the head, and anchoring of the pulling element may be on the head. Anchoring of the pulling element may be by means of complemental anchor formations on respectively the pulling element and in the passage through the head. The anchor formations may allow relative motion in one direction, which is the direction of pulling, only.

The hole may extend through said one or more bodies to a far opening remote from said near opening, the shank extending beyond said far opening, and being dilated to abut a surface around said far opening.

In accordance with a second aspect of this invention, there is provided a fastener including a head having a passage therethrough and a bearing face; a dilatable shank connected to or connectable to the head to extend away from the bearing face; a pulling element connected to or engageable with the dilatable shank and selectively drawable through the passage in the head to impart compressive stress to the dilatable shank to dilate it; and anchor formations for anchoring the pulling element.

The passage may commence on the bearing face.

In use, when the fastener is located in a hole into bodies to be fastened to each other, the bearing face will abut a surface around a near opening at one end of the hole, the shank will extend into the hole and the pulling element will return via the pasage in the head. When the hole extends through the bodies to a far opening remote from said near opening, the shank will extend beyond the far opening and will abut a surface around said far opening when dilate.

The anchorformations may include complemental anchorformations respectively on the pulling element and in the passage to anchor the pulling element in the passage. The anchor formations may allow displacement of the pulling element through the passage in one direction, and may prevent displacement in the opposite direction. Thus, the anchor formations may be in the form of sets of teeth transverse to the direction of displacement, the teeth of at least one, and preferably both, of the sets of teeth being resilient and

obliquely oriented to allow relative sliding in said one direction and to act as hooks in said opposite direction. The teeth may be in the form of serrations.

In one embodiment, the dilatable shank, and the pulling element may be interconnected in series and may be flexible to form an elongate dilatable member which can be looped and passed back along itself in doubled up configuration, the dilatable member having sufficient resistance to bending to form a loop having a transverse dimension or diameter at least larger than a transverse dimension of the elongate member in its doubled up configuration.

Thus, when the fastener is located in the hole mentioned above, the doubled up elongate member will be slidable along the hole, but the loop will have a cross dimension larger than the hole.

In another embodiment, the dilatable shank may be hollow to form an elongate member having a passage therethrough in register with the passage through the head, the pulling element being engageable with the elongate member or shank remote from the head and extending through the passage through the elongate member or shank and the passage through the head. The pulling element may have a head which is in abutment with the elongate member or shank to impart compressive stress to the elongate member or shank when the pulling element is pulled. The elongate member or shank may be configured to buckle when under compressive stress. The elongate member or shank may be tubular. The buckle-ability of the elongate tubular member or shank under compressive end loading may be provided by having its wall thickness thin enough, or by providing openings in its wall. The openings may be circumferentially or axially spaced or may be both circumferentially and axially spaced. The openings may be axially elongate and may be arranged symmetrically in series. Thus the shank may have a plurality of cage like structures arranged in series, joined by axially spaced lands. This permits the shank to be cut to a desired length before use. A further feature to ensure outward buckling of the end of the shank under compressive end loading, may be provided by having a spigot formation extending from the head of the pulling

element. The spigot formation will be arranged to fit snugly into the end of the shank, and to extend part way into the shank.

The fastener may be in the form of one or more synthetic polymeric mouldings.

In accordance with another aspect of this invention, there is provided a fastener in the form of a moulding of synthetic polymeric material including a head having a passage passing therethrough and retaining formations in the passage; a shank which is fast with the head; and a pulling element connected to or engageable with the shank and being of a size and shape to pass through the passage and having engagement formations for engaging with the retaining formations in the head for retaining the pulling element under tension in use.

The various aspects of the invention will now be described by way of example with reference to the accompanying drawings.

In the drawings: Figure 1 shows a first embodiment of a fastener in accordance with the invention in three-dimensional view; Figure 2 shows a longitudinal section at ll-li in Figure 1; Figure 3 shows a cross-section at III-III in Figure 1; Figure 4 shows an axial section of the fastener of Figures 1 to 3 in position securing two layers; Figure 5 shows a second embodiment of a fastener in accordance with the invention in longitudinal section; Figure 6 shows an axial section of the embodiment of Figure 5 in position prior to securing a layer to a panel; Figure 7 shows an axial section corresponding to Figure 6 in which the fastener has been secured in position;

Figure 8 shows a third embodiment of a fastener in accordance with the invention in side elevation; Figure 9 shows a longitudinal section at IX-IX in Figure 8; Figure 10 shows a fourth embodiment of a fastener in accordance with the invention in three-dimensional view; Figure 11 shows a plan view at XI-XI in Figure 10; Figure 12 shows a longitudinal section at XII-XII in Figure 11; Figure 13 shows a fifth embodiment of a fastener in accordance with the invention, in side elevation; Figure 14 shows a sectional plan at XIV-XIV in Figure 13; and Figure 15 shows an axial sectional elevation of the fastener of Figure 13 when secured in position in use.

Referring to Figures 1 to 4 of the drawings, reference numeral 10 refers generally to a fastener in accordance with the invention. The fastener 10 has a head 12 having a bearing face 12.1 which is adapted in use to bear against a workpiece. The head 12 has a passage 14 extending from an opening 16 in the face 12.1.

The fastener further includes a resiliently flexible shank 18 extending from the face 12.1 adjacent to the opening 1 6. An elongate resiliently bendable pulling element 20 extends from the end of the shank 18. The pulling element 20, is of smaller cross-section than the shank 18 and is shaped and dimensioned to fit snugly and slidably into the passage 14.

Retaining means in the form of a plurality or serrations 14.1 is provided within the passage 14. The pulling element 20 has engaging means in the form of serrations 20.1, toothed rack fashion, for co-operating with the serrations 14.1. The sets of serrations 14.1 and 20.1 are complementally oblique to allow relative displacement in one direction and to engage like hooks to prevent relative displacement in an opposite direction.

As a first step in use, the pulling element 20 and shank 18 are passed in series through aligned openings 23 provided for this purose through layers 22,24 to be fastened to each other. The elongate and resilient bendable pulling element 20 is folded over, doubled back on itself, and its end is inserted via the openings 23 into the opening 16. The end of the puiling element is pulled through the opening 16 and along the passage 14 until a head formation 18.2 is formed on that side of the layers remote from the head 12. The protruding end of the pulling element is then snipped off flush with the head 12.

The layers 22,24 are sandwiched between the head formation 18.2 and the head 12.

The Applicant has found that the head formation 18.2 can advantageously be looped around a body for fastening said body to a layer or layers.

Referring to Figures 5,6 and 7 of the drawings, there is shown an embodiment 110. The embodiment 110 is similar, even identical, in may respects to the embodiment 10. Thus, conveniently, like reference numerals are used to denote like features and components. Also the embodiment 110 is not again described in respect of the similar features.

The fastener 110 has a composite shank 118 formed of two resilient flexible shanks 118.1,1 18.2 spaced on either side of the passage 1 14, having serrations 114.1.

The fastener 110 has a pulling element 120, having serrations 120.1. The pulling element 120 has, at one end a head 121 by means of which it abuts a free end of the shank 118, the pulling element 120 extending in between the shanks 118.1,1 18.2 and through the passage 14. The head 121 has a projected area (or plan) corresponding to the projected area or plan of the shank 118.

In use, the shank 118, with the pulling element 120 in position, is introduced through registering openings 23 in the panels 22,24 as shown in Figure 6 of the drawings. Thereupon the pulling element 120 is pulled through the passage 114, causing the shanks 118.1,118.2 to buckle as shown in Figure 7 of the drawings, thereby forming a head-like formation 18.3 to bear against the remote face of the panel 22. When the pulling element 120 has been securely gripped by the serrations in 114.1 in the passage 114, then the projecting end of the pulling element is snipped off flush with the head 112.

Referring to the embodiment shown in Figures 8 and 9 of the drawings, this embodiment can be used when layers or panels are accessible from both sides. In this embodiment, the elongate pulling element 220 is provided with a head 221 which is further provided with locating recesses 221.1 spaced on either side of the puiling element 220. These recesses 221.1 are positioned and dimensioned to accommodate a shank in the form of a pair of locating prongs 218 projecting from the face 212.1 of the head 212. The prongs 218 are positioned on either side of the opening 216.

In use, the pulling element 220 and the prongs 218 are threaded through aligned holes in layers and the end of the pulling element 20 is then drawn through the passage 214 until the layers are firmly gripped between the head formations 221. Thereupon the projecting portion of the pulling element 220 is cut off flush with the head 212.

Referring now to Figures 10,11 and 12 of the drawings, reference numeral 318 indicates a tubular shank having at one end a plurality of circumferentially spaced arms 319 extending longitudinally. The fastener further includes an elongate wedge-like pulling element 320 having, in this embodiment, three longitudinally spaced bulbous formations 321 decreasing in diameter from one end toward a pulling tab provided with serrations 320.1 which in use are adapted to co-operate with corresponding serrations 314.1 provided inside the passage 314 of rectangular section of the shank 318.

The fastener further includes a sleeve 360 of porous, resiliently compressible material around the arms 319.

The inner surfaces of the arms 319 are provided with longitudinally spaced recesses 319.1,319.2 and 319.3, to match and to accommodate the bulbous formations 321.1,321.2 and 321.3.

The end of the shank 318, remote from the arms 319, is provided with an external screw thread to accommodate a complemental internal screw thread of the head 312. The head 312 has shoulders to facilitate manual screwing of the head 312 onto the threaded shank 318. The shank 318 then defines the passage through the head 312.

In use, a hole is drilled into a wall, of a diameter to receive the sleeve 360 snugly. The shank 318, with the sleeve 360 and the pulling element 320 in position within the tubular shank 318, is received as a unit in the hole.

Then the pulling element 320 is withdrawn causing the bulbous formations 321 to wedge against the arms 319 and to become seated in the respective recesses 319. The serrations 320.1 of the pulling element 320 engage with the teeth 314.1 on the inside of the shank 318. The shank 318 is then firmly held in the hole in the wall, by the frictional grip exerted by the resiliently compressible porous sleeve 60 urged into engagement with the inner surface of the hole by the bulbous formations 321 acting on the arms 319. The head 312 is then threaded by hand onto the screw thread of the shank 318, over a hook or an eye supported by the shank and which is intended to be anchored on the wall. The protruding end of the pulling element 320 can then be cut off flush with the end of the head 312, to present a neat appearance.

Referring now to Figures 13,14 and 15 of the drawings, reference numeral 410 refers generally to a fastener which includes a head 412, a tubular shank 418 and a pulling element 420. The shank 418 has a axially spaced cage like formations 418.1 joined by circumferential lands 418.2. The cage like

formations are formed by circumferentially spaced axially elongate openings 418.3 between similarly spaced limbs 418.4 extending between circumferentially intact portions 418.2.

In practice, the shank 418 will have a number of cage like formations 418.1 spaced axially in series, permitting cutting of the shank 418 to a length to suit the length of the hole in which the fastener is to be secured.

The pulling element 420 has a head 421 and a spigot 425 in series at one end. The head 421 overhangs the spigot 425 as shown at 427. The head 421 corresponds in plan to the plan of the shank 418.

In use, the shank 418 is cut to the desired length. The pulling element 420 is inserted into the end of the shank 418, an end of the pulling element 420 projecting through the passage 414 in the head 412 and the head 421 abutting the free (cut off) end of the shank 418. The spigot 425 seats in the end of the shank 418 and the overhanging shoulder 427 of the head 421 bears against the end of the shank 418. The shank 418 with the assembled pulling element 420 is then inserted into the hole 23 through the layers 22,24 to be fastened, such that the end cage 418.1 projects beyond the end of the hole.

Thereupon, tension is applied at the projecting end of the pulling element 320, thereby applying a compressive load to the end of the shank 418 via the shoulder 427. The limbs 418.4 then buckle under the load as shown at 418.41 in Figure 15, and form a head-like formation 418.5 as shown in Figure 15. The formation 418.5 is maintained by the serrations 420.1 being engaged with the serrations 414.1 in the passage 414.

After being secured in position the projecting end of the pulling element 420 may be cut off flush with the head 412, for the sake of neatness.