Expanded – threaded – driven – headed – tool-deformed – or locked-thr – Headed fastener element with nut – washer – securing means or cap – Cap over the head
Reexamination Certificate
2000-10-04
2004-02-03
Saether, Flemming (Department: 3679)
Expanded, threaded, driven, headed, tool-deformed, or locked-thr
Headed fastener element with nut, washer, securing means or cap
Cap over the head
C411S386000, C411S361000
Reexamination Certificate
active
06685410
ABSTRACT:
This application is the U.S. national phase of International Application No. PCT/GB00/03232, filed Aug. 22, 2000, which designated the U.S., the entire contents of which is hereby incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to the protection of a fastener primarily during placement through a passage in a plurality of elements where the passage contains a sealing substance.
2. Discussion of Prior Art
A known fastener will now be described with reference to
FIGS. 1 and 2
of the accompanying drawings.
A known fastener will now be described with reference to
FIGS. 1 and 2
of the accompanying drawings, in which:
FIG. 1
is a schematic cross section of a known pin-tail locking bolt positioned for fastening to sheet elements, and
FIG. 2
is an elevation of the known pin-tail locking bolt of
FIG. 1
drawn to a larger scale.
Referring to
FIG. 1
, it is known for elements such as two sections
10
,
12
of an aircraft wing skin to be joined together in a fluid-tight manner. A passage
14
is formed through the skin sections
10
,
12
, the passage having a countersink
16
in an outer surface of the section
12
. The skin sections
10
,
12
have a flowable sealant
13
between them and sealant is also applied to the countersink
16
.
Looking at
FIG. 2
, a pin-tail locking bolt
18
comprises a head
20
, a shank
22
of diameter d
1
and a pin-tail part
24
of diameter d
2
, where d
1
is greater than d
2
. Towards one end
26
of the pin-tail part
24
arranged furthest from the head
20
, a series of annular grooves
28
is provided. Towards the end
30
of the shank
22
spaced from the head, a series of annular grooves
32
is also provided. A point of weakness
34
defined by a reduced cross section is provided between the shank
22
and the pin-tail part
24
.
Referring again to
FIG. 1
, the pin-tail locking bolt
18
is advanced through the passage
14
. A pneumatic tool
38
has jaws
40
that receive the grooves
28
of the pin-tail bolt
18
and has a front face
41
that abuts the skin section
10
. The jaws
40
then pull hard on the pin tail bolt
18
to clamp the skin sections
10
,
12
together. An annular collar
42
is then swaged onto the grooves
32
in the shank
22
, for example, by pneumatic devices
44
. Continued pulling on the pin-tail bolt
18
by the pneumatic tool
38
eventually breaks the pin-tail part
24
away from the shank
22
of the installed bolt
18
, at the point of weakness
34
. However, as the pin-tail bolt
18
is advanced through the passage
14
, sealant
13
squeezed into the passage
14
from between the skin sections
10
,
12
and excess sealant applied to the countersink
16
is picked up by and contaminates the grooves
28
. It is conventional to clean the pin-tail bolt
18
and particularly the grooves
28
, with a rag prior to applying the pneumatic tool
38
. However, such a cleaning operation is not efficient and the pneumatic tool
38
generally becomes contaminated by the sealant which is undesirable.
An aim of the invention is to protect the fastener against such contamination.
SUMMARY OF THE INVENTION
According to a first aspect of the invention there is provided a sheath for protecting a fastener as it is passed through a passage, the sheath defining a first hollow at a first end for receiving part of a fastener and a second hollow at a second end suitable for collecting a substance in the passage.
In that way, when the sheath-covered fastener passes through a passage occupied, say, by sealant, the first end of the sheath protects the fastener from contamination by the sealant whilst the second end of the sheath can collect sealant.
The sheath can be removed from the fastener after passing through the passage to expose the part of the fastener which is clean.
Preferably, the sheath further comprises an internal barrier to prevent sealant which enters the second hollow making contact with the fastener.
The barrier is preferably an internal wall, most preferably a bulkhead.
The sheath is preferably of circular cross sectional shape.
The sheath may be provided with at least one rib on its outer surface. The or each rib is preferably in the form of a circumferential projection, for example of annular form. The rib arrangement is useful for wiping sealant from the surface of the passage as the sheath passes there through.
Preferably the or each rib has a radially outer surface of convex cross-sectional shape.
Preferably, there are at least two ribs on the outer surface of the sheath.
According to a second aspect of the invention there is provided a sheath according to the first aspect of the invention or any of the consistory clauses relating thereto with a fastener therein.
The sheath is preferably a push or sliding fit on the fastener. Preferably, the fit is such that sealant is unable to pass between the sheath and that part of the fastener therein.
Where the barrier is provided, the fastener may abut the barrier. In that way, the barrier will provide a surface against which the fastener abuts to push the sheath through a passage.
Preferably, the part of the fastener within the sheath has grooving thereon.
Preferably, the fastener is a bolt and most preferably, a pin-tail locking bolt. In the latter case, the sheath preferably receives the pin-tail part of a pin-tail bolt. In that way, the pin-tail part remains protected from contamination by the sealant.
Where the pin-tail part of a locking bolt is of a lesser diameter than the main body of a pintail locking bolt, the sheath is preferably of a thickness that makes the pin-tail part with the sheath thereon similar in diameter to that of the main body thereby enabling the sheath to fit over the pin-tail part and still pass through the passage for which it is intended.
According to a third aspect of the invention there is provided a method for protecting a fastener during movement through a passage having a substance therein from which part of the fastener is to be protected, the method comprising the steps of, positioning the said part of the fastener within a sheath, advancing the fastener and the sheath through the passage such that the sheath shields the said portion of the fastener from contamination by the substance in the passage, and then removing the sheath from the fastener.
Preferably, the method comprises providing the fastener in the form of a bolt, most preferably a pin-tail locking bolt.
In the latter case, the method may comprise the step of fitting the sheath on the pintail part of the bolt.
Preferably, the method comprises forming the passage in a plurality of elements such as skin panels for an aircraft.
The sheath may be of greater length than the passage.
REFERENCES:
patent: 3817146 (1974-06-01), Scott
patent: 4032043 (1977-06-01), Lajovic
patent: 4210179 (1980-07-01), Galer
patent: 4525915 (1985-07-01), Rich
patent: 5908277 (1999-06-01), Richards
patent: 6196270 (2001-03-01), Richards
patent: 0978280 (1964-12-01), None
patent: 1 515 038 (1978-06-01), None
patent: 2283552 (1995-05-01), None
Allen Terence P
Parson Reginald D
LandOfFree
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