GB2446581A

GB2446581A - Fastener Installation Tool

Info

Publication number: GB2446581A
Application number: GB0702792A
Authority: GB
Inventors: Aiden Robert Dear; Angraj Kumar Seewraj
Original assignee: Avdel UK Ltd
Current assignee: Avdel UK Ltd
Priority date: 2007-02-14
Filing date: 2007-02-14
Publication date: 2008-08-20
Anticipated expiration: 2027-02-14
Also published as: GB0702792D0; TW200909093A; WO2008099132A8; WO2008099132A1; GB2446581B; AU2007347114A1

Abstract

A fastener installation tool for installing fasteners of the type in which a part of the fastener is broken off during the installation process, which fastener installation tool is provided with collection means 4 for collecting broken-off fastener parts during operation of the tool, the collection means being removably connected to the tool; which tool is provided with a shutter 10 and resilient urging means 12 , wherein when the collection means is connected to the tool, the shutter is maintained in an open position, to allow the passage of broken-off fastener parts from the tool into the collection means, and wherein, when the collection means is disconnected from the tool, on operation of the tool, the resilient urging means exerts a pressure on the shutter thus urging the shutter into a closed position wherein a contact surface of the shutter obstructs the though bore thus causing broken-off fastener parts to remain within the tool and apply a pressure to the contact surface, and wherein when the pressure applied by broken-off fastener parts to the shutter surface exceeds the pressure exerted by the resilient urging means, the shutter is caused to open sufficiently to allow the ejection of a broken-off fastener part.

Description

Fastener Installation tool This invention relates to a safety device

for a fastener installation tool provided with collection means for collecting parts of fasteners which are broken off during installation of the fastener.

Fastener installation tools induding collection means are known, for example as described in GB 2372475B. Such collection means may be removable to allow the tool operator to empty the broken-off parts, i.e. stems, from the collection means. Installation tools having removable collection means may include a safety plate, which is actuated when the collection means is removed from the tool. The safety plate when actuated provides a fixed barrier normal to the path of the stems, and prevents stems from being ejected from the tool without the collection means being in place, which could cause injury to the operator.

However, a problem with the use of such a safety plate is that the stems may jam in the installation tool. Continued use of the installation tool is possible even when the collection means has been removed, with the safety plate acting to keep the broken-off fastener parts within the tool. Such continued use causes stems to build up in the Installation tool piston, necessitating partial dismantling of the tool to clear the build up.

It is an aim of the present invention to overcome the aforementioned problems.

Accordingly, the present invention provides, in one aspect, a fastener installation tool as claimed in claim I of the appended claims.

An advantage of the present invention is that the potential dangers of use of using the fastener installation tool whilst the collector bottle in disconnected are significantly reduced. When the tool is used without the collection means being attached, broken-off fastener parts such as stems are caused to build up within the tool, thus applying an

I

increasing force to the surface of the shutter. When a particular number of broken-off fastener parts have collected within the tool i.e. when the pressure applied to the surface has reached a certain limit, the shutter is forced, against the resilient urging means, to open and allow a single part to be ejected. Thereafter, a single stem is ejected on each successive use of the tool. As the resilient urging means act to reduce the speed at which the shutter can open, the speed of ejection of each single stem is lower than the speed at which they are ejected when the collection means is connected to the tool. Therefore operation of the tool without the collection means being connected does not represent a safety risk to the operator, and dismantling of the tool to retrieve the broken-off stems is not necessary.

Preferably the surface of the shutter to which pressure is applied is angularly displaced relative to the axis of the passage of the broken-off stems through the tool. This allows the broken-off stems to apply a pressure vector to the surface until the pressure limit is reached, wherein the shutter is forced open.

Alternatively, the shutter could be hinged, with the resilient urging means acting against the hinge to maintain the shutter in a closed position, until the requisite pressure is reached, whereupon the shutter is forced to hinge open to allow the ejection of a single broken-off fastener part. Again, the resilient urging means would act to cause the single broken-off fastener part to be ejected at a speed lower than if the shutter was not impeding its passage.

An embodiment of the present invention will now be described by way of example and with reference to the accompanying drawings in which: Figure 1 is a cross sectional view of the installation tool with the collector bottle connected and the shutter in the open position; Figure 2 is cross sectional view of the installation tool with the collector bottle disconnected and the shutter in the closed position; Figure 3 is a cross-sectional view of the installation tool with the collector bottle disconnected and the shutter in the forced-open position; and Figures 4, 5 and 6 are enlarged cross-sections of the shutter mechanism in the positions of Figure 1, Figure 2 and Figure 3 respectively.

Figure 7 is a perspective view of an alternative shutter in accordance with the present invention, with a conical contact surface.

Referring to Figures 1 to 3, a tool 2 Is provided with a collection means comprising a bottle 4 connected to the rear of the tool. A through bore 6 having an exit 30 is provided to allow ejection of broken-off fastener stems 8. A shutter mechanism Is provided comprising a shutter 10, piston 14, and resilient urging means comprising a spring 12, which is operable to close the exit 30 under action of the spring 12.

As illustrated in Figures 4 to 6, the piston 14 has a cavity 38 into which a first arm 18 Is Insertable. The first arm 18 Is linked via a second arm 20 to the shutter 10.

During normal use of the tool 2, the bottle 4 is connected to rear of the tool, as illustrated in Figure 1. On installation of the bottle. pressurised air is forced through an aperture 22 into the piston casing 24, thus causing the piston 14 to be forced outwardly away from the aperture 22. A seal 34 is provided to prevent leakage of the pressurised air between the piston 14 and the casing 24. As the piston 14 is forced outwardly, the first arm 18, second arm 20 and the shutter 10 are caused to move correspondingly. The resilience of the spring 12 is overcome by the air pressure acting upon the piston 14 and therefore the spring 12 is compressed within a shutter cavity 28 provided in the shutter 10. The piston 14 and shutter 10 are subsequently maintained in this position, i.e. wherein shutter 10 abuts edge 26, whilst pressurised air is fed into cavity 36 via aperture 22. In this position, shutter 10 does not obstruct the exit 30, therefore on installation of a fastener, broken-off stems 8 which are ejected into through bore 6 can pass through exit 30 and into the connected bottle 4. As the passage of the stems 8 is not impeded, the speed at which the stems are ejected through the tool and exit will not be reduced.

Once the bottle 4 has been disconnected from the tool, the supply of pressunsed air into cavity 36 via aperture 22 is caused to cease.

Therefore the resilience of the spring 12 acts to urge the shutter 10 into the closed position of Figures 2 and 5. The position of the shutter 10 therefore acts to block the through bore 6, thereby preventing the ejection of broken-off stems 8 through exit 30.

When the shutter 10 is in the closed position, the first use of the tool 2 whilst the bottle 4 is disconnected will cause a broken-off stem 8 to be ejected into and remain within the through bore 6. Subsequent uses of the tool will be possible, and will cause further broken-off stems 8 to be ejected into and remain within the through bore 6. When a sufficient number of stems 8 has built up in the through bore 6, the first stem which was broken off will be caused to abut against a contact surface 32 of the shutter 10. Contact surface 32 is angled relative to the axis of the through bore 6, therefore the abutting stem 8 causes a vector force to be applied to the contact surface 32 of the shutter 10. Beyond this point, a further use of the tool 2 will cause one or more further stems 8 to be ejected into the through bore 6, thus causing an increase in the force applied by the first stem to the contact surface 32 of the shutter 10. This Increased force will be sufficient to overcome the resilience of the spring 12, and cause the shutter 10 to be forced into an the open position, wherein the first arm 18 is caused to be removed from the cavity 38, and the spring 12 is caused to compress into the shutter cavity 28, allowing the first stem 8 to be ejected through the exit 30. The resilience of the spring 12 will cause the stem 8 to pass through exit 30 at a significantly lower speed than would be achieved if the bottle 4 was connected and the shutter was maintained in the open position.

Figure 3 shows a broken-off stem 8 forcing the shutter 10 open and hence allowing the ejection of the stem through exit 30. However, after the first stem 8 has passed through exit 30, there will be insufficient force acting upon the shutter contact surface 32 to overcome the resilience of the spring 12, therefore the spring 12 will urge the shutter back into the closed position of Figures 2 and 5. Each subsequent use of the tool 2 will likewise allow the ejection of a single stem 8 through the exit 30, (i.e. the stem abutting against shutter surface prior to use).

Once the bottle 4 is reconnected to the tool 2, the shutter 10 will return to the open position. The first use of the tool 2 subsequent to reconnection of the bottle 4 will cause the stems within the tool to be ejected through exit 30 intO the bottle 4.

In an alternative embodiment, the angled shutter 10 may be replaced by a snap fit shutter, which will be forced to snap into an open position when a sufficient number of broken-off fastener stems 8 have built up within the tool, and will subsequently snap into a closed position.

In a further alternative embodiment, the sprmg could be substituted by an alternative resilient urging means, for example, air pressure.

In another alternative embodiment, the angled shutter 10 may have its contact 32 surface substituted with a complete or part conical form, as illustrated in Figure 7. In this embodiment, a solid angled shutter 10' is provided with an integral conical cut 40. Broken-off stems will be urged into the apex of the conical cut 40, thus providing a further degree of control to the passage of broken-off stems when the shutter 10' Is forced into the open position by urging the stems to be ejected centrally.

Claims

Claims 1. A fastener installation tool for installing fasteners of the

type in which a part of the fastener is broken off during the installation process, which fastener installation tool is provided with collection means for collecting broken-off fastener parts during operation of the tool, the collection means being removably connected to the tool; which tool is provided with a shutter and resilient urging means, wherein when the collection means is connected to the tool, the shutter is maintained in an open position, to allow the passage of broken-off fastener parts from the tool into the collection means, and wherein, when the collection means is disconnected from the tool, on operation of the tool, the resilient urging means exerts a pressure on the shutter thus urging the shutter into a closed position wherein a contact surface of the shutter obstructs the though bore thus causing broken-off fastener parts to remain within the tool and apply a pressure to the contact surface.

and wherein when the pressure applied by broken-off fastener parts to the shutter surface exceeds the pressure exerted by the resilient urging means, the shutter is caused to open sufficiently to allow the ejection of a broken-off fastener part.
2. A fastener installation tool as claimed in Claim I wherein the contact surface of the shutter is angularly displaced relative to the axis of the passage of broken-off fastener parts.
3. A fastener installation tool as claimed in Claim 1 wherein at least part of the contact surface of the shutter Is provided with a conical cut.
4. A fastener installation tool as claimed in any one of the preceding claims wherein the resilient urging means comprises a spring.
5. A fastener installation tool as claimed in Claim 1 wherein the shutter includes a snap fit plate.
6. A fastener installation tool as claimed in any one of the preceding claims wherein the shutter is caused to open and maintained in an open position by means of compressed air.
7. A fastener installation tool substantially as hereinbefore described and with : * reference to the accompanying figures.

* . 20
S.

S S * .*

7. A fastener installation tool substantially as hereinbefore described and with reference to the accompanying figures.

AMENDMENTS TO THE CLAIMS HAVE BEEN FILED AS FOLLOWS:-Claims 1. A fastener installation tool for installing fasteners of the type in which a part of the fastener is broken off during the installation process, which fastener installation tool is provided with collection means for collecting broken-off fastener parts during operation of the tool, the collection means being removably connected to the tool; which tool is provided with a shutter and resilient urging means.

:.. 15 wherein when the collection means is connected to the tool, the shutter is S... * *

S... maintained in an open position, to allow the passage of broken-off fastener parts from the tool into the collection means, via a through bore provided in the tool, *SI * and wherein, when the collection means is disconnected from the tool, on *5 * S * ..* operation of the tool, the resilient urging means exerts a pressure on the shutter thus urging the shutter into a closed position wherein a contact surface of the shutter obstructs the through bore thus causing broken-off fastener parts to remain within the tool and apply a pressure to the contact surface, and wherein when the pressure applied by broken-off fastener parts to the shutter surface exceeds the pressure exerted by the resilient urging means, the shutter is caused to open sufficiently to allow the ejection of a broken-off fastener part.

2. A fastener installation tool as claimed in Claim I wherein the contact surface of the shutter is angularly displaced relative to the axis of the passage of broken-off fastener parts.

3. A fastener installation tool as claimed in Claim I wherein at least part of the contact surface of the shutter is provided with a conical cut.

4. A fastener installation tool as claimed in any one of the preceding claims wherein the resilient urging means comprises a spring.

5. A fastener installation tool as claimed in Claim I wherein the shutter includes a snap fit plate.

6. A fastener installation tool as claimed in any one of the preceding daims wherein the shutter is caused to open and maintained in an open position by means of * * ** compressed air. ** *S S S...