GB2191239A - Rotatable fasteners - Google Patents

Abstract

The fastener e.g. for a door 1 comprises a housing 16 within which is rotatably mounted a fastener member 3 with a head 4 formed as an annular wall 6 which is provided with a spaced axially projections 8,9 for engagement by complementary castellated end 10 of a tool 11. A projection means 19 is freely rotatably mounted within the fastening member 3 and defines with the housing 16 an annular passage which provides the only access for tool end 10 to projections 8,9. The protection means preferably includes a recess or a screw-driver slot to divert attention from the tool engagement means. As shown, fastener member 3 has an externally threaded anchor end 5 received in internally threaded aperture in pawl 2 and is anchored thereto by threaded pin 12; a door frame is received between pawl 2 and door 1 to hold door 1 shut. The protection means 19 has a cylindrical head 20, a stem 21 being rotatably secured to member 3 by spread end 23. <IMAGE>

Description

SPECIFICATION Rotatable fasteners This invention is concerned with improvements in and relating to rotatable fasteners.

It has become a problem with equipment which is publicly exposed to prevent the equipment being tampered with. For example where parts of the equipment, such as cover plates, are secured by rotatable fasteners which have an operative end exposed, such as bolts or screws, idle hands or purposefully destructive hands will endeavour to loosen or removed the fasteners by any means to hand such as a nail file or coins.

It is an object of this invention to provide a rotatable fastener which will discourage such attempts or thwart or at least make such attempts to undo a rotatable fastener more difficult.

According to one aspect of this invention there is provided a rotatable fastener which comprises, a rotatable fastener member receivable in a first element, the fastener member having an axially exposed operative head engageable axially by a tool to rotate the fastener member and an anchoring end for disengageably anchoring the fastener member with a second element, the fastener also including a housing which is receivable by the first element and which freely rotatable receives the fastener member, the operative head of the fastener member having an annular operative part, an annular end surface thereof having axially extending tool engagement means, which are engageable by an annular end of a tool having axially extending means which will made driving engagement with the tool engagement means and which lie within the housing, the fastener member operative head including an axially extending protection means freely rotatable relative to the fastener member and overlying at least the internal surface of the annular operative part, the protection means and the housing defining together an annular passage for access by the annular tool end to the tool engagement means, while denying radial access to the radially directed faces of the fastener member or to the axially extending tool engagement means.

The fastener member anchoring end may be threaded to receive and make engagement with threaded means on the second element.

The housing is preferably externally threaded and is clamped to the first element by a clamping ring threaded on to the housing and the protection means may a have a screw driver slot or polygonal sided recess as a means to divert attention away from the tool engagement means. The annular passage will be dimensioned to radially and axially to prevent insertion of thin nosed pliers.

Further features and advantages of the present invention will appear from the following description of an embodiment, given by way of example only, reference being made to the accompanying drawing which is an exploded view of a rotatable fastener and tool, the fastener being in cross section, the tool and tool engagement means of the fastener being in perspective, and different forms of the end of the tool and the tool engagement means of the fastener being included.

The rotatable fastener in this embodiment is associated with a member 1, e.g. a door and a rotatable pawl 2, spaced from the door to receive a door frame (not shown) between the door and the pawl so that the door may be held shut by the pawl or be released for opening. This aspect of the embodiment is purely for descriptive purposes.

The fastener comprises a rotatable fastener member 3 having an operative head 4 and an anchor end 5. The operative head 4 is an annular wall 6 having an axially exposed annular end face which is castellated, having two axially projecting members 8, 9 so that the member 3 can be rotated by an annular complimentary castellated end 10 of a turning tool 11. The number of castellations is optional.

The anchor end 5 is externally threaded to make threaded engagement with an internally threaded aperture in the pawl and is itself internally threaded in a bore 5a at least adjacent that end sufficient to receive a threaded pin 12 which pin anchors the member 3 to the pawl.

Surrounding the member 3 is a housing 16 received in an aperture in the door, the door being clamped in between a shoulder 17 on the housing and a ring 18 threaded on the housing. The housing denies access to the radially outwarly directed face of the member 3 while a protection means 19 denies access to the radially inwardly directed face of member 3. The protection means comprise a cylindrical head 20 rotatably secured to the member 3 by a stem 21 received in a bore 22 of member 3, end 23 of stem 21 being spread where bore 22 meets the larger diameter bore 5a to retain the head 20 in member 3.

It will be seen that the pawl is spaced from the door by the housing and by rotating the member 3, the pawl, by virtue of a frictional engagement between it and the member 3 induced by a spring 25, can be rotated by the member 3 when that member is rotated by the tool. Since the member 3 is only accessible by way of the passage defined by the housing and the head 20, no radial face of that member being accessible for gripping the head nor any radial access to any circumferentially directed face of the axial projections 8, 9 the fastener has a high degree of security against tamper attempted from the face of the door remote from the pawl. To divert anyone tempted to try, a screw slot 26 or a polygonal recess may be provided in the end face of the head. Tampering by means of such a slot or recess will cause the head to rotate but nothing else will be achieved.

If selective security is required the projections 8, 9 may be spaced angularly by different angles a as illustrated, as between fasteners so that the fastener can only be rotated by a corresponding tool. Only seven different angles are illustrated purely as example of many possible angles.

Claims (6)

1. A rotatable fastener which comprises: a rotatable fastener member receivable in a first element, the fastener member having an axially exposed operative head engageable axially by a tool to rotate the fastener member and an anchoring end for disengagebly anchoring the fastener member with a second element, the fastener also including a housing which is receivable by the first element and which freely rotatable receives the fastener member, the operative head of the fastener member having an annular operative part, an annular end surface thereof having axially extending tool engagement means, which are engageable by an annular end of a tool having axially extending means which will make driving engagement with the tool engagement means and which lie within the housing, the fastener member operative head including an axially extending protection means freely rotatable relative to the fastener member and overlying at least the internal surface of the annular operative part, the protection means and the housing defining together an annular passage for access by the annular tool end to the tool engagement means, while denying radial access to the radially directed faces of the fastener member or to the axially extending tool engagement means.

2. A rotatable fastener according to claim 1 wherein the tool engaging means comprises two axial projections which are circumferentially spaced apart whereby a tool having axial recesses to receive the projections is required to make driving engagement with the operative head.

3. A rotatable fastener according to claim 1 or claim 2 wherein the protection means has an exposed tool engaging profile.

4. A rotatable fastener according to any preceding claim wherein the protection means includes a stem which is captively mounted in a bore in the fastener member to retain the protection means in operative position.

5. A rotatable fastener according to any preceding claim wherein a pawl is secured to the anchoring end of the fastening member.

6. A rotatable fastener substantially as herein described with reference to the accompanying drawing.