AU655778B2

AU655778B2 - Fastener having recessed, non-circular head, and fastener-driving tool

Info

Publication number: AU655778B2
Application number: AU84890/91A
Authority: AU
Inventors: George G. Dewey; Michael Janusz
Original assignee: Illinois Tool Works Inc
Current assignee: Illinois Tool Works Inc
Priority date: 1990-10-03
Filing date: 1991-09-30
Publication date: 1995-01-12
Anticipated expiration: 2011-09-30
Also published as: DE9115987U1; ES2065789B1; GB2250559A; GB9312661D0; BE1006015A3; CA2051728C; FR2668802A1; GB9120661D0; FI914649A; MX9101272A; GB2268241A; NO913876L; SE9102846D0; SE9102846L; NO913876D0; ES2065789R; CA2051728A1; JPH07103889B2; IT1250503B; ITTO910742A0

Description

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AUSTRALIA

Patents Act 655778 COMPLETE SPECIFICATION

(ORIGINAL)

Class Int. Class Application Number: Lodged: Complete Specification Lodged: Accepted: Published: Priority Related Art: 0 0 *Name of Applicant: o o'Illinois Tool Works Inc.

Actual Inventor(s): 9 eo George G. Dewey Michaol Janusz Address for Service: PHILLIPS ORMONDE FITZPATRICK Patent and Trade Mark Attorneys S'1" 367 Collins Street .,41 Melbourne 3000 AUSTRALIA Invention Title: *FASTENER HAVING RECESSED, NON-CIRCULAR HEAD, AND FASTENER-DRIVING TOOL Our Ref 228897 POF Code: 77887/1431 SThe following statement is a full description of this invention, including the best method of performing it known to applicant(s): ~zr .1 6006 j

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FASTENER-DRIVING TOOL Technical Field of the Invention This invention relates to a fastener-driving tool having a non-circular or polygonal socket for driving a fastener. This invention provides an improved way to center the non-circular socket and the non-circular head relative to each othe.

Background of the Invention So-called stand-up screw guns, which are powered by trigger-actuated, electric motors, are exemplified in 1 Murray U.S. Patent No. 3,960,191, Dewey U.S. Patent No.

4,236,555, and Dewey U.S. Patent No. 4,397,412 and are available commercially from ITW-Buildex (a unit of Illinois Tool Works Inc.) of Itasca, Illinois, under its AUTOTRAXX trademark.

20 Typically, stand-up screw guns employ driving members with driving tips, such as driving tips adapted to drive Phillips-head screws. Fastener-driving tools of other types, which may be powered by electric motors or by pneumatic motors, employ driving members with driving 25 sockets, which fit axially over conforming heads of fasteners, such as screws or bolts. Typically, the t sockets and fastener heads are non-circular or polygonal when viewed axially. Commonly, the sockets and fastener heads are hexagonal when viewed axially.

30 Often, it is difficult for a user to center the Snon-circular socket of such a tool and the non-circular head of such a fastener, particularly if a 2 stand-up screw gun is used. Although a bolt or machine screw can be manually started for a few turns into a prethreaded hole in a workpiece, it is difficult for a user to stabilize a screw having a non-circular head and having a drilling or tapping tip before the screw has been driven for a few turns into a workpiece. Centering of the non-circular socket of a fastener-driving tool and the non-circular head of such a screw, therefore, can be especially difficult for a user.

If the non-circular socket of such a fastenerdriving tool and the non-circular head of such a fastener are not centered relative to each other, it is possible for the fastener, the workpiece, or both to be 0. damaged if an attempt is made to drive the fastener into "15 the workpiece via the fastener-driving tool. The noncircular socket may be damaged also.

Therefore, there has been a need, to which this invention is addressed, for an improved way to center the non-circular socket of such a fastenerdriving tool and the non-circular head of such fastener relative to each other.

Summary of the Invention This invention provides an i roved fastener having a head that is non-circular wen viewed axially.

Moreover, this invention provide/improvements in a fastener-driving tool having adriving member with a socket that is non-circula when viewed axially, whereby the improved tool is us ul for driving the improved j fastener. This inv ion facilitates centering of the non-circular socet of the improved tool and the noncircular head f the improved fastener relative to each other via -/centering pin coacting with a concave recess in the nn-circular head.

The improved fastener, which has an axis, has a ead and a shank, which has a threaded portion. The shank may be fully threaded or may be alternatively

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Of, 2a- Therefore, there has been a need for an improved way to center the non-circular socket of such a fastener-driving tool and the non-circular head of such a fastener relative to each other.

Accordingly, it is an object of this invention to provide a fastener-driving tool which overcomes at least some of these disadvantages.

Summary of the Invention According to a first aspect of this invention there is provided a fastener-driving tool, useful to drive a fastener having a longitudinal axis, a shank having a threaded portion, and a head which is non-circular when viewed axially and which has a concave recess extending into said head, the tool including: a tubular housing having an internal peripheral surface, and a lower forward end for enveloping said head of said fastener; r a driving member having a longitudinal axis, and a socket portion which is non-circular when viewed axially 20 and which is movably disposed within said tubular housing so as to be movably engaged with said internal peripheral it* surface of said tubular housing and thereby be movably guided by said tubular housing, including said lower I Ct forward end thereof enveloping said head of said fastener, in order to be properly aligned with respect to said head of said fastener, enveloped by said lower forward end of said tubular housing, and thereby be axially fitted over and drivingly engaged with said non-circular head of said fastener so as to define a driving relationship therewith S..1 30 by which said driving member is arranged to drive said fastener in a driving direction; port means defined within a first sidewall portion of said tubular housing for delivering a fastener into a first hollow, upstream portion of said tubular housing, as viewed in said driving direction, and toward an axial position of said tool which is substantially coaxial with said longitudinal axis of said driving member; S support means disposed downstream of said port r /C3! means, as viewed in said driving direction, and pivotably I 3mounted within the vicinity of second sidewall portions of said tubular housing, disposed downstream of said port means as viewed in said driving direction, for engaging said shank of said fastener so as to position said head of said fastener within said lower forwward end of said tubular housing, as viewed in said driving direction, and in a substantially coaxial manner with respect to said socket portion of said driving member prior to engagement of said socket portion of said driving member with said non-circular head of said fastener; a centering pin having a longitudinal axis substantially coinciding with said axis of said driving member, and being assembled to said driving member for axial movement relative to said socket portion of said driving member between an extended position and a retracted position wherein said centering pin is biased toward said extended position, said centering pin having a convex end extending axially through said socket portion of said driving member in such a manner that said convex %0 20 end of said centering pin extends axially beyond said o socket portion of said driving member when said centering pin is disposed at said extended position so as to fit 6*00 :into said concave recess of said head of said fastener prior to engagement of said socket portion of said driving 25 member with said n(n-circular head of said fastener so as *to ensure said coaxial alignment of said fastener head owith said socket portion of said driving member, and wherein further, said convex end of said centering pin is axially movable from said extended position and into said o 30 socket portion to said retracted position when said socket V4J portion is guidingly moved by said lower forward end of said tubular housing and toward said fastener, enveloped within said lower forward end of said tubular housing, so as to permit said socket portion of said driving member to be axially fitted over and engaged with said non-circular head of said fastener; and I: means for moving said driving member between an inoperative position, at which said centering pin and said 39/ socket portion are spaced from said head of said fastener,

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4 and an operative position at which said centering pin is fitted at said convex end thereof into said concave recess defined within said head of said fastener and is moved axially from said extended position with respect to said socket portion to said retracted position inside said socket portion so as to center said socket portion and said head of said fastener relative to each other, and at which said socket portion is guidably moved along said internal peripheral surface of said tubular housing, including said lower forward end thereoc enveloping said head of said fastener, so as to properly engage said non-circular head of said fastener enveloped within said lower forward end of said tubular housing and centered with respect to said socket portion of said driving member by said centering pin.

In one embodiment the convex end of the centering pin has a frusto-conical surface converging towards the axis of the centering pin.

In an alternative embodiment the convex end of the 0 20 centering pin has a plurality of substantially triangular 4 facets converging towards the axis of the centering pin.

Advantageously said convex end of the centering pin has six said facets conforming substantially to a pyramid having a regular, hexagonal base.

25 Preferably an annular retainer is disposed at a Sfixed position within the driving member. Such a retainer has a central aperture through which the centering pin extends for axial movement of the centering pin relative to the retainer. The centering pin has a radially outwardly projecting rib arranged to co-act with the retainer and thereby check axial movement of the centering pin.

Preferably the fastener-driving tool includes resilient biasing means for biasing the centering pin towards engagement with the rib.

According to a second aspect of this invention there is provided a fastener-driving tool for driving a fastener 13 having a longitudinal axis, a shank, and a head which has f.390 a concave recess defined therein, the tool including: a tubular housing having an internal peripheral surface, and a forward end for enveloping said head of said fastener; a driving member having a longitudinal axis, and socket means which is movably disposed within said tubular housing so as to be movably engaged with said internal peripheral surface of said tubular housing and thereby be movably guided by said tubular housing, including said forward end thereof enveloping said head of said fastener, so as to be properly aligned with respect to said head of said fastener, enveloped by said forward end of said tubular housing, for engaging said head of said fastener so as to define a driving relationship therewith by means of which said driving member is arranged to drive said fastener in a driving direction; centering pin means having a longitudinal axis substantially coaxial with said longitudinal axis of said driving member and movably mounted upon said driving °member for axial movement between an extended position at 20 which a convex end of said centering pin means is disposed beyond said socket means of said driving member so as to engage said concave recess of said fastener head prior to engagement of said socket means with said head of said fastener so as to ensure coaxial alignment of said fastener head with said socket means, and a retracted position at which said centering pin means is retracted within said socket means so as to permit said socket means 4 CI to subsequently engage said head of said fastener, in accordance with said ensured coaxial alignment 30 predetermined by said centering pin means and as movably J guided by said internal peripheral surface of said tubular housing, including said forward end of said tubular housing, as a result of said movable engagement of said socket means with said internal peripheral surface of said tubular housing, and thereby define said driving relationship therewith; port means defined within a first sidewall portion 't of said tubular housing for dt Uivering a fastener into a 3\ first hollow, upstream portion L 4d tubular housing, as 0if /i c-

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I .r I: i i:p lid b~l]~ i #4 *0 4 4* 4 *9 #44 .4 #4 1 9 4 44 t1 I tr viewed in said driving direction, and toward an axial position of said tool which is substantially coaxial with said longitudinal axis of said driving member; and support means disposed downstream of said port means, as viewed in said driving direction, and pivotably mounted within the vicinity of second sidewall portions of said tubular housing, disposed downstream of said port means as viewed in said driving direction, f£,r engaging said shank of said fastener so as to position said head of said fastener within said forward end of said tubular housing, as viewed in said driving direction, and in a substantially coaxial manner with respect to said centering pin means such that upon axial movement of said fastener relative to said centering pin means and said socket means, said convex end of said centering pin means, initially axially spaced from said concave recess of said fastener head as predetermined by said engagement of said shank of said fastener by said suppor: means, can engage said concave recess of said fastener head so as to 20 ensuredly define said coaxial alignment of said fastener, said centering pin means, and said socket means, and whereupon continued axial movement of said fastener and said centering pin means r3lative to said socket means, said socket means is movably guided within said tubular housing, as a result of said movable engagement of said socket means within said internal peripheral surface of said tubular housing, including said forward end of said tubular housing which envelops said head of said fastener, so as to properly engage said head of said fastener so as to define said driving relationship therewith.

The fastener-driving tool according to the second aspect may have any one or more of the preferred features of the fastener-driving tool according to the first aspect of the invention.

Thus this invention provides a fastentr-driving tool which facilitates centering of the non-circular socket of the improved tool and the non-circular head of a fastener relative to each other via a centering pin co-acting with 39.\ a concave recess in the circular head. In essence the j improved tool comprises a combination of driving member and centering pin mounted on the driving member.

The centering pin, which has an axis coinciding generally with the axis of the driving member, is assembled to the driving member for axial movement of the centering pin between an extended position and a retracted position. The centering pin extends axially through the socket in the extended position but is retracted axially in the retracted position.

Similarly the driving member is movable between an inoperative position in which the centering pin is spaced from the fastener head, and an operative position in which the centering pin is fitted at the convex end into the recess in the fastener head. Accordingly, as the driving member is moved to the operative position, the socket and the fastener head are centered relative to each other.

S 4 4 4 9 4 D 414 9 -6pin has an annular rib, which is disposed withi e tubular extension. The rib is adapted t gage the retainer upon axial movement of t centering pin to the extended position. Moreov in the preferred construction, the ering pin is biased by a coiled spring disp within the tubular extension so as to bea gainst the rib.

These and olher objects, features, and advantages of this invention are evident from the following description of preferred embodiments of the improved fastener and the improved tool, with reference to the accompanying drawings.

Brief Description of the Drawings S.Oo Figure 1 is an elevational view of a stand-up screw gun constituting a preferred embodiment of the 0 improved tool, o* Figure 2, on a larger scale, is a fragmentary, exploded view of some components of the stand-up screw gun shown in Figure 1, along with a screw constituting a preferred embodiment of the improved fastener.

Figure 3 is an axial view of some components

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1 shown in Figure 2, namely a driving member with a noncircular socket and a centering pin, as taken along line 2 3--3 of Figure 2, in a direction indicated by arrows.

Figure 4, on a similar scale, and Figures through 8, on a larger scale, are sequential, fragmentary views through some components of the standtit& up screw gun shown in Figures 1, 2, and 3, as used to S3 drive the screw shown in Figure 2 through two decking members at an overlapped seam, into one flange of an Ibeam, which is shown only in Figure 8. Some elements shown in Figure 4 are omitted in Figures 5 through 8.

Figure 9 is an enlarged, fragmentary, elevational detail of a modified socket coacting with the screw shown in Figure 2.

Figure 10 is an enlarged, fragmentary, 1 -7-7 perspective detail of a centering pin having a modified, convex end according to an alternate embodiment of the improved tool, along with a screw according to an alternate embodiment of the improved fastener.

Figure 11, on a smaller scale compared to Figure 10, is an axial view looking upwardly at the centering pin and related components of the improved tool according to the alternate embodiment.

Detailed Description of Preferred Embodiments Although preferred and alternate embodiments of the improved tool and the improved fastener are illustrated in the drawings and are to be next od*°0 described, it is to be here understood that this o invention is not limited to these embodiments.

As shown in Figure 1 and other views, a standup screw-gun 10 constitutes a preferred embodiment of D the improved tool provided by this invention. As shown in Figures 2 and 4 through 8, the screw gun 10 is useful to drive a screw through two decking members 14, 16, at an overlapped seam, into one flange 18 of an I-beam, as in a floor or roof construction. The screw gun 10 is Sshown as used to drive a screw 20 constituting a preferred embodiment of the novel fastener provided by *o this invention.

Except as illustrated in the drawings and described herein, the screw 20 is similar to the screw disclosed in Sygnator U.S. Patent No. 4,583,898.

Thus, the screw 20, which has an axis, has a head 22, a shank 24, and a washer-like portion 26 between the head 22 and the shank 24. The head 22 is hexagonal when viewed axially, so as to adapt the head 22 to coact with a suitably shaped socketof a fastenerdriving tools such as the socket of the screw gun 10 to be later described. The shank 24 has a threaded portion 28 adjoiningthe washer-like portion 26 and a drilling tip 30 adjoining the threaded portion 28. Details of a I -8drilling tip like the drilling tip 30 are found in the Sygnator patent noted above.

The screw 20 differs from the screw disclosed in the Sygnator patent noted above, and from other fasteners known heretofore, in having a concave recess extending axially into the head 22, from a top surface 42 of the head 22. It is characteristic of the preferred embodiment of the novel fastener provided by this invention that the concave recess 40 has a frustoconical surface 46 defining a conical angle and converging toward the axis of the screw 20. It is not necessary for the frusto-conical surface 46 to converge to a point on the axis of the screw 20. At the top surface 42, the frusto-conical surface 46 defines a continuous, upper edge 48 conforming to a circle.

I 4 4 4, ldvantageously, the concave recess 40 provides a datum that is useful in centering a socket of a 59. fastener-driving tool, such as the screw gun 10 to be next described, and the screw head 22 relative to each other before the fastener-driving tool is used to drive the screw 0 c c Except as illustrated in the drawings and described herein, the screw gun 10 is similar generally to stand-up screw guns disclosed in the Murray and Dewey patents noted above and specifically to stand-up screw guns available commercially from ITW-Buildex, upra, under its ACCUTRAXX trademark.

Broadly, the screw gun 10 comprises a nosepiece 50 having various com onents to be later described, two tubes in a telescoping relationship, namely an outer, upper tube 52 and an inner, lower tube 54 mounting the nosepiece 50, a driving member 56 mounted rotatably within the tubes 52, 54, and arranged to drive other components to be later described, and a driver 58 mounted to the upper tube 52. The driver 58 is powered by an electric motor (not shown) and is under it CCTA rdeak S ,tgp actuated. The tubes 52, 54, are biased by internal springi not shown) to an elongated condition. The tubes 52, 54, are adapted to be axially telescoped to a shortened condition, when a user presses downwardly on the driver 58 with the nosepiece 50 pressed against a workpiece.

Further, the screw gun 10 comprises a screwfeeding tube 62, which is mounted to the nosepiece via a mounting block 64 having a passageway 66 for guiding screws from the screw-feeding tube 62 into the j nosepiece 50. Each screw must be individually dropped into the screw-feeding tube 62 in such manner that the shank of such screw leads the head of such screw.

The nosepiece 50 has an upper, tubular portion 0ao 72 arranged to receive each screw from the passageway oOo 66, a lower, tubular portion 74, and a pair of lower flanges 76, 78, on opposite sides of the tubular portion 74. The flanges 76, 78, extend below the tubular portion 74 and are designed to be downwardly pressed oa aagainst a workpiece when the screw gun 10 is used to Sdrive a screw into or through the workpiece.

The nosepiece 50 has a pair of gripping jaws 25 80, 82, which are mounted between the flanges 76, 78, for pivotal movement of each of the jaws 80, 82, between a closed position and opened positions. Each of the e *o jaws 80, 82, is shown in its closed position in Figures o, 4 through 7 and in one of its opened positions in Figure 8. The gripping jaw 80 is mounted for pivotal movement on a pivot pin 84, which is mounted to the flanges 76, 78, and is biased to its closed position by a coiled spring 86. The spring 86 is disposed operatively between an upper end 88 of the jaw 80 and the tubular portion 74 of the nosepiece 50. The end 88 has a pocket receiv" T one end of the coiled spring 86, The i 10 gripping jaw 82 is mounted for pivotal movement on a pivot pin 92, which is mounted to the flanges 76, 78, and is biased to its closed position by a coiled spring 94. The spring 94 is disposed operatively between an upper end 96 of the jaw 82 and the tubular portion 74 of the nosepiece 50. The end 96 has a pocket 98 re;eiving one end of the coiled spring 94.

When each of the gripping jaws 80, 82, is in its closed position, the jaws 80, 82, are disposed loosely to grip the shank of a screw, as the shank 24 of the screw 20 is shown as gripped loosely in Figures 4 through 7, and further to prevent the head of the screw from dropping through the jaws 80, 82, if the nosepiece is not against a workpiece. Pivotal movement of the jaw 80, as biased by the spring 86, is limited by engagement between a shoulder 100 on the jaw 80 and the tubular ,f i t portion 74 of the nosepiece 50. Pivotal movement of the jaw 82, as biased by the spring 94, is limited by engagement between a shoulder 102 on the jaw 82 and such portion 74.

The driving member 56, which has an axis, has a tubular extension 108. The tubular extension 108 defines a socket 110 extending axially into the tubular extension 108. The socket 110 is hexagonal when viewed "25 axially, conforms generally to the head 22 of the scrnw and is adapted to be axially fitted over the screw head 22. The tubular extension 108 is connected mechanically to the driving member 56, by having a *partly threaded portion 112 threaded onto a partly threaded, tubular portion 114 of the driving member 56.

A centering pin 120, which has an axis that coincides generally with the axis of the driving member 56, is disposed within the tubular portion 114 of the driving member 56 for axial movement of the centering pin 120 relative to the driving member 56 between an extended position and retracted positions. In the r extended position, the centering pin 120 extends axially through the sock~et 110, as shown in Figures 4, 5, and 6.

The centering pin 120 is shown in a retracted position in Fi"gures 7 and 8.

The centering pin 120 has a convex end 122 hiaving a frusto-conical surface 124 converging toward the axis of, the centering pin 120. The frusto-conical surface 124 defines a conical angle that, preferably, is about equal to but not greater than the conical angle defined by the frusto-conical surface 46 of the concave recess 40 in the head 22 of the screw The centering pin 120 has an annular rib 126, A which is disposed within the tubular portion 114 of the driving member 56. An annular retainer 128 is pressed 0 15 into the tubular portion 114, below the annular rib 126, in such manner that the retainer 128 is held friction'k. ly by the tubular portion 114. The rib 126 is 0 0, adapted to engage the retainer 128 upon axial movement of the centering pin 120 to the extended position.

Thus, the retainer 128 retains the rib 126, so as to prevent the centering pin 120 from dropping from the tubular portion 114. A coiled spring 130 is disposed 0 within the tubular portion 114, around the centering pin 120, so as to bea~r downwardly against the rib 126 and thus to bias the centering pin 120 toward the extended position.

The centering pin 120 is adapted to be axially fitted at the convex end 122 into the concave recess in the head 22 of the screw 20. Also, the centering pin 120 is adapted to be axially moved from the extended position to a retracted position when pressed upwardly into the tubular extension 108. The centering pin 120 is used to center the socket 110 and the screw head 22 relative to each other.

The driving member 56 is movable between inoperative positions, in which the centering pin 120 is j -12spaced from the head 22 of the screw 20, and an operative position. In the operative position, h centering pin 120 is fitted at the convex end 122 axially into the concave recess 40 in the screw head 22 and is moved axially from the extended position to a retracted position, whereby the centering pin 120 centers the socket 110 and the screw head 22 relative to each other.

When the driving member 56 has been moved to the operative position by a user pressing downwardly on the driver 58 and telescoping -the tubes 52, 54, to the shortened condition with the nosepiece 50 pressed against a workpiece, such as the decking member 14 shown in Figure 8 and other views, the screw gun 10 maybe then O 15 actuated to drive the screw 20 via the driving member 56 with the socket 110 fitted axially over the head 22 of the screw 20, as illustrated in sequential stages in £4 Figures 4 through 8. As shown in Figures 6, 7, and 8, the convex end 122 is fitted loosely into the concave recess 40, so as not to impart frictional drag as the screw 20 is driven. Moreover, as shown in Figure 8, the tubular extension 108 engages the washer-like portion 26 of the screw 20 after the socket 110 has been fitted axially over the head 22 of the screw 20, so as to limit axial movement of the socket 110 over the head 20 of the screw If the screw 20 should be slightly tipped, as suggested in Figure 5, and if the centering pin 120 were I II omitted, a user could face some difficulty in fitting the socket 110 axially over the head 22 of the screw Advantageously, the centering pin 120 facilitates centering the socket 110 and the screw head 22 relative to each other, so as to obviate such difficulty.

As shown in Figure 9, one possible enhancement of this invention is to chamfer 1owqr edges 140 defined by the socket 110. Upper corners 142 defined by the 1 13 head 22 of the screw 20 are rounded in a known manner.

The chamfered edges 140 and the rounded corners 142 facilitate centering the socket 110 and the screw head 22 relative to each other.

In Figures 10 and 11, primed reference numbers are used to designate elements that are similar or analogous to elements designated by similar, unprimed reference numbers in the other views.

An alternate embodiment of the improved fastener provided by this invention is constituted by a screw 20' similar to the screw 20, except that the concave recess 40' in the head 22' of the screw 20' has six substantially triangular surfaces 160, which are 0oo arranged in a regular array about the axis of the screw f ,*15 20'. Such surfaces 160 define a continuous, upper edge 162, which conforas to a regular hexagon having each of o> six respective sides parallel to an adjacent one of six flat surfaces 164 of the screw head 22'.

An alternate embodiment of the improved tool provided by this invention is constituted by a stand-up screw gun 10' similar to the screw gun 10, except for the centering pin 120' and the annular retainer 128', which is fitted into the tubular extension 114' in such manner that the retainer is held frictionally by the tubular extension 114'.

The centering pin 120' is hexagonal in crosssection, except for an annular rib (not shown) similar to the annular rib 126 used in the screw gun 10. The annular retainer 128' is shaped complementarily, as 44 30 shown in Figure 11, so that the centering pin 120' rotates conjointly with the socket 110', which is hexagonal when viewed axially. The centering pin 120' and the socket 110' are oriented similarly in a rotational sense, whereby each of six axially extending, flat surfaces 166 defined by the centering pin 120' is parallel to an adjacent one of six flat surfaces 168 14 defined by the socket 110' in the tubular extension 108'.

The convex end 122' of the centering pin 120' conforms generally to the concave recess 40' in the head 22' of the screw 20' and has six substantially triangular facets 170 arranged in a regular array about the axis of the centering pin 120'. The facets 170 converge toward the axis of the centering pin 120' and conform substantially to a pyramid having a regular, hexagonal base. The convex end 122' has a small, blunt tip 172. Because the centering pin 120' rotates conjointly with the socket 110', the centering pin 120' orients the screw 20' in such manner that the socket .'t1 l5 110' and the head 22' of the screw 20' are oriented similarly in a rotational sense, when the convex end 122' of the centering pin 120' is fitted axially into the concave recess 40' in the head 22 of the screw Thus, when the socket 110' and ,e screw head 122' are oriented similarly in a rotational sense as well as centered relative to each other, the socket 110' can be axially fitted over the screw head 22' without interference.

Various modifications may be made in the 25 improved tool or in the improved fastener without departing from the scope and spirit of this invention.

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Claims

1. A fastener-driving tool, useful to drive a fastener having a longitudinal axis, a shank having a threaded portion, and a head which is non-circular when viewed axially and which has a concave recess extending into said head, the tool including: a tubular housing having an internal peripheral surface, and a lower forward end for enveloping said head of said fastener; a driving member having a longitudinal axis, and a socket portion which is non-circular when viewed axially and which is movably disposed within said tubular housing so as to be movably engaged with said internal peripheral surface of said tubular housing and thereby be movably guided by said tubular housing, including said lower forward end thereof enveloping said head of said fastener, in order to be properly aligned with respect to said head of said fastener, enveloped by said lower forward end of 20 said tubular housing, and thereby be axially fitted over 9 0! and drivingly engaged with said non-circular head of said 0 4: fastener so as to define a driving relationship therewith by which said driving member is arranged to drive said fastener in a driving direction; port means defined within a first sidewall portion t "ti of said tubular housing for delivering a fastener into a 'first hollow, upstream portion of said tubular housing, as viewed in said driving direction, and toward an axial Sposition of said tool which is substcntially coaxial with said longitudinal axis of said driving .,te/ber; S support means disposed downstream of said port means, as viewed in said driving direction, and pivotably mounted within the vicinity of second sidewall portions of said tubular housing, disposed downstream of said port means as viewed in said driving direction, for engaging said shank of said fastener so as to position said head of said fastener within said lower forwward end of said L tubular housing, as viewed in said driving direction, and z, 49• in a substantially coaxial manner with respect to said x 16 socket portion of said driving member prior to engagement of said socket portion of said driving member with said non-circular head of said fastener; a centering pin having a longitudinal axis substantially coinciding with said axis of said driving member, and being assembled to said driving member for axial movement relative to said socket portion of said driving member between an extended position and a retracted position wherein said centering pin is biased toward said extended position, said centering pin having a convex end extending axially through said socket portion of said driving member in such a manner that said convex end of said centering pin extends axially beyond said socket portion of said driving member when said centering pin is disposed at said extended position so as to Fit into said concave recess of said head of said fastener prior to engagement of said socket portion of said driving member with said non-circular head of said fastener so as :to ensure said coaxial alignment of said fastener head with said socket portion of said driving member, and wherein further, said convex end of said centering pin is axially movable from said extended position and into said ,socket portion to said retracted position when said socket portion is guidingly moved by said lower forward end of 25 said tubular housing and toward said fastener, enveloped within said lower forward end of said tubular housing, so 'as to permit said socket portion of said driving member to tit', be axially fitted over and engaged with said non-circular head of said fastener; and means for moving said driving member between an I inoperative position, at which said centering pin and said socket portion are spaced from said head of said fastener, al± an operative position at which said centering pin is fitted at said convex end thereof into said concave recess defined within said head of said fastener and is moved axially from said extended position with respect to said socket portion to said retracted position inside said S socket portion so as to center said socket portion and said head of said fastener relative to each other, and at L i of said tubular housing for di-.Jivering a tascener ii.;u C first hollow, upstream portion L d tubular housing, as 7 7 U 1 H-r 17 goo. o 40 .o.4 44 004 0 0 00 04 44 o 44 S44 4 4,4 *544 which said socket portion is guidably moved along said internal peripheral surface of said tubular housing, including said lower forward end thereof enveloping said head of said fastener, so as to properly engage said non-circular head of said fastener enveloped within said lower forward end of said tubular housing and centered with respect to said socket portion of said driving member by said centering pin.

2. A fastener-driving tool according to Claim 1, wherein the convex end of the centering pin has a frusto-conical surface converging towards the axis of the Centering pin.

3. A fastener-driving tool according to Claim 1, wherein the convex end of the centering pin has a plurality of substantially triangular facets converging towards the axis of the centering pin.

4. A fastener-driving tool according to Claim 3, wherein the convex end of the centering pin has six said facets conforming substantially to a pyramid having a 20 regular hexagonal base.

5. A fastener-driving tool according to any one of Claims I to 4, wherein an annular retainer is disposed at a fixed position within the driving member, the retainer having a central aperture through which the centering pin extends for axial movement of the centering pin relative to the retainer, and the centering pin having a radially outwardly projecting rib which is arranged to co-act with the retainer thereby checking axial movement of the centering pin. 30

6. A fastener-driving tool according to Claim including resilient biasing means for biasing the centering pin towards engagement with the rib.

7. A fastener-driving tool for driving a fastener having a longitudinal axis, a shank, and a head which has a concave recess defined therein, the tool including: a tubular housing having an internal peripheral surface, and a forward end for enveloping said head of said fastener; '59" N a driving member having a longitudinal axis, and -18- socket means which is movably disposed within said tubular housing so as to be movably engaged with said internal peripheral surface of said tubular housing and thereby be movably guided by said tubular housing, including said forward end thereof enveloping said head of said fastener, so as to be pioperly aligned with respect to said head of said fastener, enveloped by said forward end of said tubular housing, for engaging said head of said fastener so as to define a driving relationship therewith by means of which said driving member is arranged to drive said fastener in a driving direction; centering pin means having a longitudinal axis substantially coaxial with said longitudinal axis of said driving member and movably mounted upon said driving member for axial movement between an extended position at which a convex end of said centering pin means is disposed beyond said socket means of said driving member so as to engage said concave recess of said fastener head prior to engagement of said socket means with said head of said S. 20 fastener go as to ensure coaxial alignment of said fastener head with said socket means, and a retracted o o position at which said centering pin means is retracted within said socket means so as to permit said socket means to subsequently engage said head of said fastener, in accordance with said ensured coaxial alignment ,predetermined by said centering pin means and as movably 'guided by said internal peripheral surface of said tubular housing, including said forward end of said tubular .housing, as a result of said movable engagement of said S" 30 socket means with said internal peripheral surface of said tubular housing, and thereby define said driving relationship therewith; port means defined within a first sidewall portion of said tubular housing for delivering a fastener into a first hollow, upstream portion of said tubular housing, as viewed in said driving direction, and toward an axial K position of said tool which is substantially coaxial with I said longitudinal axis of said driving member; and K /39 support means disposed downstream of said port I 19 19 means, as viewed in said driving direction, and pivotably mounted within the vicinity of second sidewall portions of said tubular housing, disposed downstream of said port means as viewed in said driving direction, for engaging said shank of said fastener so as to position said head of said fastener within said forward end of said tubular housing, as viewed in said driving direction, and in a substantially coaxial manner with respect to said centering pin means such that upon axial movement of said fastener relative to said centering pin means and said socket means, said convex end of said centering pin means, initially axially spaced from said concave recess of said fastener head as predetermined by said engagement of :.aid 'o shank of said fastener by said support means, can engage 15 said concave recess of said fastener head so as to ensuredly define said coaxial alignment of said fastener, S* said centering Fin means, and said socket means, and 4444 whereupon continued axial movement of said fastener and said centering pin means relative to said socket means, said socket means is movably guided within said tubular housing, as a result of said movable engagement of said Ssocket means within said internal peripheral surface of said tubular housing, including said forward end of said tubular housing which envelops said head of said fastener, so as to properly engage said head Of said fastene,' so as to define said driving relationship therewith.

8. A fastener-driving tool according to Claim 7, wherein the convex end of the centering pin means has a frusto-conical surface converging towards the axis cf the Centering pin.

9. A fastener-driving tool according to Claim 7, Swherein the convex end of the centering pin means has a plurality of substantially triangular facets converging towards the axis of the centering pin.

10, A fastener-driving tool according to Claim 9, wherein the convex end of the centering pin means has six said faces conforming substantially to a pyramid having a 0 regular, hexagonal base. 3'

11. A fastener-driving tool substantially as A I 20 herein described with respect to any one of the embodiments illustrated in the accompanying drawings. DATED 18 October 1994 PHILLIPS ORMONDE FITZPATRICK Attorneys for: ILLINOIS TOOL WORKS INC. joau-;116 9 0 0 *990 9 0* 1 9* $0 00 0 0 9 0 *9 000* 9 9 *9 00 0 99 9 00 0 9000 0909 9990 0 9 9 '9 019' 999 090~ $9 I I 1/39 L8414e ABSTRACT An improved fastener having a non-circular head with a concave recess providing a datum useful in centering the head relative to a non-circular socket of S a driving member. The recess may have a frusto-conical wall defining an upper, circular edge or substantially triangular walls de/ining an upper, non-circular edge. An improved tool useful to drive the improved fastener. In the improved tool, a driving member has a tubular *.4,10 extension with a non-circular socket, and a centering :pin is movable axially toward an extended position, in which a convex end of the centering pin fits into the concave recess when the socket is fitted axially over the fastener head. The centering pin "s biased toward the extended position. 1£ h i