FASTENING SYSTEM

Abstract: Figure 1 shows the terminal portion of screwdriver blade having stepped portions of successively smaller dimension towards its tip for use with any of a range of screws with different dimensions where the largest of the screws will have a complementary stepped slot to be engaged by all of the portions (12, 13, 14) of the blade, smaller screws will have a slot to be engaged by the portions (12) and (13) only, and the smallest will have a recess to be engaged by the tip portion (12) only. In other embodiments the portion of the tool may be hexagonal or of other non-circular shape and again the screws are to have complementary recesses. The invention is useful with screws, bolts and other fastening pins both threaded or non-threaded of a wide range of types, and in the case of non-threaded fasteners the tool and recess cross section need not be non-circular.

Description: FASTENING SYSTEM This invention relates to screws and like fastenings, herein collectively referred to as 'pins', apparatus and methods for making the same and systems for handling and installing and removing the same. The term pin is used herein to include elongated elements used for fastening purposes of many different kinds and configurations. One example is wood screws which as well known have a tapering shank. Another example is machine screws or bolts which are of uniform diameter. The term is to include headless pins, for example studs as well as headed pins where the head .nay be of any desired shape for example the well known round head or hexagon head. Finally the terra is to include special purposes fastening pins which are without any screwthread and which may or may not be provided with projections or recesses as part of the fastening function. Such pins are made in an enormous range of sizes, lengths, materials, and kinds. They are installed by a large variety of different tools or sizes of tools, for example screwdrivers, alien keys and spanners. The tool used is always dependent upon the size of the pin for where a particular kind of fastener is made in a range of sizes, a like range of tools is employed. Thus, hexagon head bolts need a different spanner for each bolt diameter. Conventional transversely slotted counter-sunk head wood screws are most efficiently installed using a screwdriver blade which precisely fits the slot, and the slot length varies with the size of the head and the gauge of the screw, and even the slot width varies in the same way. Consequently, a workman dealing with a range of pins needs a range of tools. If the correct tool is absent, the workman may well employ a substitute which is not entirely appropriate or a so called universal tool such as pliers or an adjustable-jaw wrench, and these often damage the pins making subsequent removal and replacement more difficult. The object of the invention is to solve this problem. According to the invention a system for installing ' and/or removing pins as defined comprises the use of a tool and a selection made from a plurality of pins of different sizes, in which:- (a) The tool has a shaft terminating in a series of at least two axially juxtaposed portions and successively smaller dimension normal to the axis of the shaft and approaching the free end of the shaft, (b) The larger sizes of said pins each have a stepped recess complementary in shape and size to said shaft termination, - whereas - (c) smaller sizes of said pins have a stepped recess complementary in shape and size to one or more of the smaller dimension portions of said shaft termination but not including a recess portion complementary in shape and size to the largest of said portions. Hence, one and the same tool may be used for pins of a whole range of sizes. For example, the tool may have three differently sized portions in series at its working tip, of which the smallest only engages in a complementary recess in pins of a first range of sizes; in which the smallest and next portion engage in both portions of a complementary two stepped recess in the head of any of a second and larger range of sizes, and all three portions engage in a three stepped recess in the head of a third and largest range of pins. However, any number greater than two portions or steps may be involved. The essential result is that a worker dealing with such pins needs only a single tool instead of a series of tools. In mass production manufacture of articles needing a plurality of pins of different sizes, and/or kinds, the invention offers a substantial simplification in that a workman needs only a single tool to install the different pins. If the mass production uses programmed robotic movements of a tool, the same applies in that one and the same tool may be used successively on disparate pins without it being necessary to change the tool. Preferably the tool and recess are arranged so that the pins may be supported on the tool, and in this case the tool can be inserted into one of the series of pins, and transfer it to the installation site and then install it. This may be done by making the tool a pushfit, drivefit or interference fit in the pin recess. In order to apply rotational drive to the pins, which will be required where a screwthread is used, the cross-sectional shape of the tool and recess must include at least one non-circular part. The successive tool portions and recess portions could be for example hexagonal but other non-circular shapes can be used. Pins according to the invention may be recessed at either end or both ends, as appropriate to need. Thus the hexagon headed machine screw could be provided with the recess of the invention at the end of the screw shank thus enabling the shank to be held stationary whilst the nut is tightened by another tool. Various pins according to the invention will now be considered:- Self-tapping screws usually have a relatively uniform diameter shank except for a tapering end portion and are usually provided with a head for example a counter-sunk head or a round head. These screws are most conveniently provided with the recess of the invention in the head. Wood screws usually have a tapered shank with a pointed end, the shank having a spiral male thread formed thereon and again a head of any desired peripheral shape and transverse cross-section: the recess will again be provided in the top face of the iiead remote from the s ank. Studs, that is to say lengths of (usually) uniform diameter rod provided with a screwthread or threads thereon, may be adapted to the invention by providing the recess in one or both end faces. Machine screws and bolts, differing in the proportion of the length of the shank provided by the screwthread, may have heads of any desired shape and may be provided with a recess of the invention in one or both ends i.e. in the head and/or in the free end of the shank. Non-threaded pins may be used in the invention for example cotter pins used to angularly couple one part within another and these may be either parallel pins or taper pins. The recess complementary to the tool may be provided in one or both ends. Yet another kind of fastener pin is that commonly employed for fixing trim panels in automobiles, usually made as injection mouldings in synthetic resinous materials for example nylon and often with some kind of shank projection or recess to snap engage with the complementary part or to be engaged by a small angular movement when located in the other part. Such pins may also have the recess provided in one end of the shank and/or in the head at the other end of the shank. The tool of the invention may be a tool bit for insertion in a chuck or collet of a screwdriver or like tool either manually or power driven, and either free as a hand held tool or mounted such as on a robotic arm. Or the tool may be adapted for use in a wrench such as a torque wrench and/or a ratchet tool. Preferably the bit or tool has a shank which is of the same cross-section or shape and dimensions as needful for the largest of the recess portions of the range of fasteners with which the tool is to be used and be integrally or unitarily formed or provided on its free end with the further stepped portions. Preferably, although not necessarily, both or all of the portions, according to the number used are of the same transverse ie cross-sectional shape but different dimensions. The invention further consists in a panel or reamer for forming or perfecting the desired profiled recess. In accordance with a further aspect, threaded pins according to the invention have said recess at one end and a complimentary male projection at the other end, and a plurality of said pins is asse.mbled in a line with the projections and recesses engaged. The assembly may be used in an insertion tool having a magazine so that the tool bit engages in the free recess at one end of the line, and the pin at the opposite end of the line can be rotated to be installed, with a rotation transferred from pin to pin along the line by the interengaged projections and recesses. Hence, and by way of example, if there are twenty pins in the line, the tool can be used to insert the twenty pins in twenty different holes, before being replenished with a new assembly. The assemblies can be held together for example by clips or packing material which is discarded as the pins are used. Various embodiments of the invention are now more particularly described with reference to the accompanying drawings in which :- Figure 1 is a fragmentary perspective view of the working tip of a screwdriver-tool; Figure 2 is a plan view of a screw head for use with the tool in Figure 1; Figure 3 is an axial section through the head portion of the screw of Figure 2 and on line II-II ; Figure 4 is a view similar to Figure 1 but showing a second tool; Figure 5 is a view similar to Figure 3 of the head end of a screw for use with the tool in Figure 4; and Figure 6 shows a tool for use in manufacturing. Referring first to Figure 1, the screwdriver blade 11 is generally conventional except that the driving end is stepped to provide a first reduced portion tip 12, and an intermediate reduced portion tip 13 extending from the free end of the shank part 14. The screv/ head of Figures 2 and 3 is provided with a first transverse slot portion 16 which extends diametrically over the whole width of the screw head and which is of a width appropriate to the thickness of the blade in the portion 14. The length of that slot 15 i.e. the diameter of the head is similar to the transverse dimension of the blade at the end 14. The intermediate portion 13 of the blade is complementary in length and width to the recess portion 17 which opens from the portion 16 towards the shank of the screw 15. The end portion 12 of the blade is complementary in dimensions to the recess portion 13 which opens even further towards the shank. Hence the end portion of the screwdriver bit 11 is generally complementary to the recess portions of the screv; 15 so that the blade .-nay be inserted therein and will locate angularly and radially relative to the screw. In this condition the screw may be carried by the blade to the place of use, inserted, and rotated to drive the screw home, or vice versa in screw removal. In the case of Figures 4 and 5, the screwdriver shank 20 is hexagonal and is formed with a reduced portion co-axial hexagon 21 as an intermediate portion, and a terminal also hexagonal and further reduced dimension portion 22, and these three portions ie the shank and the two reduced portions are complementary in cross-sectional shape and dimensions to the successive portions 25,26,27 recessed into the head of the screv/ 23. In axial length, portion 22 is complementary to the portion 27, intermediate portion 21 is complementary to the portion 26, but of course the recess portion 25 only represents the terminal zone of the length of shank 20. If desired, the shank 20 away from the end adjacent to portions 21, 22 may be of a quite different cross- section and/or diameter; similarly the screwdriver blade 11 may be of quite different cross-section and or diameter away from the end portion 14. In a modification not shown, each of the recesses terminates in a conical, frusto-conical or concave portion which may be for convenience in manufacture of the pins and particularly of the recesses therein; if desired, the insertion tool may have a complementary conical, frusto-conical or convex formation to centre in such additional portion, but without any intention to provide any torque transference thereby. The successive stepped portions of the tool may have parallel side faces, and the recess faces may be complementary. If desired however, the recess faces may be of shallow concavity and/or the tool faces may also be of shallov; concavity and the result of this would be that the apices of the hexagons (or other polygonal formations, if such are selected) permit a more effective fit between the tool and pin for transference between storage point and insertion point and better torque transference in installation. In manufacture the recesses in the pins may be punched and then possibly reamed to final shape and size. Figure 6 shows a broach or reamer having three portions, 30,32,34, of shape and dimensions corresponding to the three portions 20,21,22 of the installation tool. Ones of the flats are extended to form cutting teeth 36,33,40. This tool may be used to perfect the form of the recess in the pin by a reciprocatory movement, repeated after withdrawal and angular indexing.

Claims: CLAIMS 1. A system for installing and/or removing pins as defined comprising the use of a tool and a selection made from a plurality of pins of different sizes, in which:- (a) The tool has a shaft terminating in a series of at least two axially juxtaposed portions of successively smaller dimension normal to the axis of the shaft and approaching the free end of the shaft. (b) The larger sizes of said pins each have a stepped recess complementary in shape and size to said shaft termination, - Whereas - (c) smaller sizes of said pins have a stepped recess complementary in shape and size to one or more of the smaller dimension portions of said shaft termination but not including a recess portion complementary in shape and size to the largest of said portions. 2. A tool for use in a system of Claim 1 where the pins are threaded and the tool and recess comprise non- circular shapes comprising means for applying torque, and a shaft of a non-circular shape and size complementary to the shape and size of the largest recess portion of any of the plurality of pins with which the tool is to be used, said shaft terminating in two axially juxtaposed portions of similar non-circular cross-section and successively smaller dimension. 3. A screw-threaded pin for use in the system of Claim 1 having at one or other or both ends a recess of non- circular shape and of an axial dimension comparable to that of the smallest of the non-circular portions provided in the end of the tool. 4. A screw-threaded pin for use in the system of Claim 1 having at one or other or both axial ends a recess comprising a first portion of non-circular shape adjacent to the said end and a second and smaller recessed portion opening therefrom into the screw- threaded element, said smaller portion corresponding in shape and dimension to the smallest dimension portion of the tool termination and the larger recessed portion corresponding in shape and dimension to the next larger portion of the tool. 5. A screw-threaded element for use in the system of Claim 1 provided with a recess at one or other or both axial ends of the fastener, said recess comprising three successive portions of non-circular shape complementary to those of the shaft and termination portions of the tool and the axial dimension and shape of the two smaller recessed portions corresponding to the axial dimension and shape of the said two axially juxtaposed portions of the tool. 6. A system or a tool or an element as claimed in any preceding claim wherein the non-circular shape is hexagonal. 7. A system, a tool or a screw-threaded element as claimed in any preceding claim wherein the said portions or recess portions have substantially planar side faces which are substantially parallel to the axis of the shaft of the tool or the screv^-threaded element as the case may be. 8. A pin for use in the system of any preceding claim wherein the recess terminates in a tapering circular portion. 9. A tool for use in the system of any preceding claim where the tool terminates in a tapering circular portion. 10. A threaded pin as claimed in Claim 3 having the recess provided at one end and a complimentary projection provided at the other end, whereby a line of said pins may be assembled for use in a magazine type tool and for transmitting rotation from one to the other along the line by means of the interengaged projections and recesses. 11. A system substantially as described with reference to the accompanying drawings. 12. A tool for use in the manufacture of pins according to any preceding claim comprising a reamer of complementary shape to the whole of the tool end, and provided with cutting edges on at least part of the periphery of each of the differently dimensioned portions.

Inventors: TURNER MALCOLM, TURNER, MALCOLM
Applicants: TURNER MALCOLM, TURNER, MALCOLM
Application year: 1995
Main classification: F16B23
IPC codes: B23B43, B25B13, B25B15, F16B23, F16B27