Expanded – threaded – driven – headed – tool-deformed – or locked-thr – Having separate expander means – Frangible member
Reexamination Certificate
2000-07-28
2001-12-04
Wilson, Neill (Department: 3627)
Expanded, threaded, driven, headed, tool-deformed, or locked-thr
Having separate expander means
Frangible member
C411S053000, C411S183000
Reexamination Certificate
active
06325580
ABSTRACT:
FIELD OF THE INVENTION
The invention related generally to a mounting device and more particularly a device for mounting to hollow structure.
More particularly, the invention relates to a mounting or anchoring device for enabling the hanging of curtains and/or blinds directly to a hollow window or door frame.
BACKGROUND OF THE INVENTION
Window blinds and net-curtains are invariably hung inside the window reveal and, where possible and convenient, are hung from brackets or fittings which are attached directly to the window frame.
In order to support window-blinds or net-curtains on window-frames or on door-frames, it is necessary in the first instance to attach a support bracket or other fitting to the frame. Where the window or door frame is made of solid timber the support bracket or fitting can be supported by passing a screw through the bracket or fitting and then driving the screw into the timber frame.
However window and door-frames are, generally, not constructed from solid timber or from any other solid material but are made from materials such as &mgr;PVC, aluminium or composite materials not in solid form but in hollow multi-cavity form having a relatively thin outer wall and several separate longitudinal cavities inside.
FIG. 7
is a cross-sectional view of a known hollow multi-cavity &mgr;PVC window frame.
The support bracket or other fitting required to support window-blinds or net-curtains on hollow frames cannot be successfully attached to the frame by means of a screw for the following reasons:
(a) the outer wall of the &mgr;PVC window or door frame is usually not more than about 3 mm thick;
(b) the outer wall of an aluminium window or door frame is usually not more than about 1.5 mm thick.
These wall thicknesses are insufficient to give a screw the long term grip required to hold support brackets for window blinds or fittings for net-curtains. Furthermore, the main internal cavity in the frame is sealed against moisture and must not be breached by a screw which is driven into the frame and, thus, the screw can only penetrate the outer wall of the frame and must not penetrate beyond the first cavity of the frame.
Where screws are used by a window manufacturer to apply attachments a &mgr;PVC frame, then the &mgr;PVC must be of double thickness at the point where the screw enters the frame. Manufacturers of window-frame material do not generally provide double wall thickness where support brackets or fitting might be expected to be attached for the support of window-blinds or net-curtains.
Consequently, screws should not be, and generally are not, used to attach brackets or fittings to &mgr;PVC or to aluminium window or door frames.
While inappropriate improvised methods and materials are sometimes used by DIY enthusiasts, professional fitters of window-blinds and net-curtains do not attach support brackets or fittings directly to hollow frames by means of screws.
As an alternative to driving a screw directly into a relatively thin or relatively weak sheet material, various ‘cavity-fixings’ are available for general purposes. These general purpose cavity fixings provide a variety of ways of attaching a solid or threaded medium to the thin or weak sheet which medium is then capable of receiving and retaining a screw.
General purpose cavity fixings are successful in many thin or weak sheet applications. However because of the special constraints associated with hollow frames, general purpose cavity fixings cannot be used successfully to support window-blind brackets or fittings for net-curtains on such frames.
To be suitable for use in typical hollow frames a cavity mounting device should preferably have the following characteristics:
(a) in view of the fact that the outer wall of the frame is relatively thin and relatively weak, the fitting must be capable of providing a wide load-bearing surface to the rear of the face material. Preferably, the load-bearing surface must be wider than the typical first cavity in a hollow frame is deep;
(b) in view of the relatively shallow nature of the first cavity in the frame and the unacceptability of breaching the second cavity, the fitting must be capable of operating in a cavity no greater than about 5 mm deep i.e. it should not be necessary for the fitting to protrude more than 5 mm behind the front wall of the frame;
(c) the fitting must not require to be placed fully home in the hole in the host material before being deformed. Preferably, it should be capable of being deformed progressively as the fitting is fed into the hole;
(d) the fitting should be capable of being used in a cavity which is not as deep as the fitting is long;
(e) the fitting should be incapable of becoming wedged partly in and partly out of the hole in the host material;
(f) the fitting should be capable of being placed as close as 7 mm from the side wall of the window reveal;
(g) the fitting should adjust automatically to unpredictable obstructions inside the first cavity of the frame e.g. side walls of upper or lower cavities;
(h) the fitting should be capable of withstanding relatively heavy loads which tend to withdraw the fitting from the frame and must do so without damaging or marking the frame;
(i) the fitting should be capable of being applied with a tool which is easy to use and which can be relatively inexpensive to manufacture;
(j) the fitting should be capable of re-use i.e. the screw attaching the bracket or other fitting to the fixing should be capable of being removed and reliably replaced in the event of the bracket being removed;
(k) the fitting should lock in relation to the outer wall so as not to fall into the cavity in the event of a screw being placed in the fixing with excessive inward force;
(l) the fitting should provide a virtually flush fit with the outer surface of the outer wall of the frame; and
(m) the fitting should be capable of application by relatively unskilled operatives.
FIG. 1
shows an example of a known fitting which comprises a hollow tapered body
500
with side splits, a plurality of sharp projections on the exterior and screw threads on the interior.
After the known fitting
500
of
FIG. 1
is placed in the hole in the material
501
, a screw
502
is threaded into the fitting causing the fitting to expand outwards thus causing the sharp projections to penetrate into the side of the hole in the host material.
The fitting of
FIG. 1
is not suitable for use in the outer wall of hollow frames as the projections grip with short teeth and only into the range of the wall thickness of the outer wall which is no more than 3 mm. It does have a function for use with very light loads.
FIG. 2
shows an example of a known fitting which comprises a hollow tapered body
600
with side splits and having internal and external threads, the external threads being of a greater height at the broad end of the fitting. After the fitting of
FIG. 2
is screwed into the hole of the material
501
, a screw
502
is threaded into the fitting causing the fitting to expand and the external threads to lock deeper into the host material
501
. The fitting of
FIG. 2
is not suitable for use in the outer wall of hollow frames as it is not capable of carrying the required load without pulling out of the host material. The grip range is limited to the thickness of the outer wall which is not more than about 3 mm. It does have a function for use with very light loads.
FIGS. 3 and 4
show an example of a known fitting which comprises a hollow body
700
the interior lower part of which is threaded. A screw
502
or pulling mandrel is fitted into the internal threads thereof and is used to compress the fitting which, as a result, bulges out behind the face material
501
. The bulge
701
resists withdrawal of the fitting. This fitting is normally used in sheet metal but is not suitable for use in weaker material through which it will pull under load as it does not have a wide load-bearing area behind the face material.
FIGS. 5 and 6
shows a known fitting
800
which comprises a head
801
and a threaded end portion which are joined by a pl
Daly, Crowley & Mofford LLP
Wilson Neill
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