Pipe joints or couplings – Essential catch
Reexamination Certificate
1999-03-30
2001-03-13
Nicholson, Eric K. (Department: 3627)
Pipe joints or couplings
Essential catch
C411S530000, C411S514000, C024S200000, C239S600000
Reexamination Certificate
active
06199917
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to locking pins and, more particularly, to a twist pin for use in combination with a fluid coupling.
2. Description of the Prior Art
Various forms of locking pins have been developed for providing locking engagement between two or more parts. These fasteners include roll pins, cotter keys, head pin fasteners, hairpin fasteners, clinch pins, hitch pins and similar clips.
One particular application of typical prior art fasteners is in combination with fluid couplings
2
wherein an inner tubular member
3
is received within an outer sleeve
4
as illustrated in FIG.
1
. The inner tubular member
3
and outer sleeve
4
have coaxially aligned apertures
5
a
and
5
b
for receiving a fastener
6
which secures the relative positioning of the inner tubular member
3
and outer sleeve
4
. A typical fastener
6
used for such an application is a U-shaped retaining clip having a straight portion
7
and a crimped portion
8
. The straight portion
7
passes through the coaxially aligned apertures
5
a
and
5
b
while the crimped portion
8
engages the outside surface of the outer sleeve
4
thereby locking the pin
6
in place.
A problem associated with traditional retaining clips
6
is that they are often difficult to install within and remove from the fluid coupling
2
. As may be appreciated, upon installation and removal the crimp portion
8
must be forced outwardly by the outer sleeve
4
such that a bend may selectively lock and unlock the outer sleeve
4
and inner tubular member
3
in position. The installation and removal of conventional retaining clips
6
therefore often requires the use of special tools.
One common fluid coupling application utilizing fasteners provides for a spray head
9
of the type used in the cleaning industry supported by the outer sleeve
4
. More particularly, the spray head
9
and fluid coupling
2
are passed through a ferrule for insertion into a processing vessel. Once positioned within the vessel, the spray head
9
is utilized to clean the interior thereof.
Standard prior art retaining clips
6
have a straight portion
7
which is often too long to pass through the inner diameter of the ferrule. As such, the straight portion
7
of the retaining clips
6
are often shortened such that the straight portion
7
does not extend much beyond the outer sleeve
4
. While this permits the fluid coupling
2
to pass through the ferrule, a new problem results as the shortened retaining clip
6
is often difficult to properly position in locking engagement with the outer sleeve
4
. More particularly, the crimped portion
8
of the shortened retaining clip
6
often inhibits coaxial alignment of the straight portion
7
within the apertures
5
a
and
5
b
in the outer sleeve
4
and inner tubular member
3
. As such, assembly of the fluid coupling
2
is often a very difficult process.
Accordingly, there is a need for a locking pin which may be simply inserted and removed between cooperating parts for selectively providing a positive lock between such parts. Further, there is a need for such a pin having a compact shape thereby requiring a minimum amount of space.
SUMMARY THE INVENTION
The present invention relates to a twist pin for securing an outer sleeve to an inner member concentrically received within the sleeve. The outer sleeve includes a first cylindrical wall having an outer diameter and defining a sleeve center axis. A first pair of diametrically opposed and coaxially aligned apertures are formed within the first cylindrical wall. The inner member includes a second cylindrical wall and a second pair of apertures formed within the second cylindrical wall wherein the first and second pairs of apertures are coaxially aligned.
The twist pin for securing the outer sleeve to the inner member includes a first leg extending through the coaxially aligned first and second pairs of apertures. The first leg terminates at a first end positioned outside of the first cylindrical wall and defines a longitudinal leg axis. A sleeve plane is defined by the sleeve axis and the leg axis and essentially divides the sleeve into two equal longitudinally extending portions.
A second leg extends downwardly from the first leg and extends around the first cylindrical wall for more than 180 degrees to terminate at a second end. The second leg passes below the longitudinal axis proximate the first end of the first leg at a crossover. A clearance is defined between the second leg and the first cylindrical wall wherein the first leg is selectively rotatable about the longitudinal axis.
A passage is defined between the second leg and the longitudinal axis at the crossover. The passage has a width measured in a perpendicular direction from the longitudinal axis to the second leg, the width being at least as great as one half of the outer diameter of the sleeve for allowing the pin to slide past the sleeve when the twist pin is not in a locked position, thereby facilitating insertion and removal of the first leg within the first and second pairs of apertures.
The second leg includes an arcuate return portion having a radius greater than one half of the outer diameter of the sleeve thereby defining the clearance between the second leg and the first cylindrical wall. The second leg further includes a straight connecting portion disposed intermediate the first leg and the return portion. The connecting portion extends in substantial perpendicular relation to the longitudinal leg axis.
A locking portion is connected to the return portion of the second leg and includes a protuberance defining a bearing surface. The bearing surface is positioned below the first plane and intermediate the crossover and the second end of the second leg. The locking portion includes a first locking member and a second locking member angled relative to the first locking member to form a bend therebetween. The bend defines the protuberance and extends inwardly toward the sleeve center axis. The bearing surface is selectively engagable with the first cylindrical wall upon selective rotation of the first leg about the longitudinal axis.
When the first leg is received within the first and second pairs of apertures, the twist pin has unlocked and locked modes of operation. In the unlocked mode of operation, the first leg is freely slidable within the first and second pairs of apertures and the bearing surface of the locking portion is positioned on the same side of the sleeve plane as the return portion. As such, the bearing surface is not lockingly engaging the first cylindrical wall of the outer sleeve.
In the locked mode of operation, the second leg is pivoted about the longitudinal axis of the first leg such that the protuberance of the locking portion is disposed on an opposite side of the sleeve plane from the return portion. The bearing surface engages the outer surface of the first cylindrical wall beyond the sleeve plane, thereby preventing rotation of the first leg and subsequent pivoting movement of the second leg. The first leg of the pin is thereby secured within the first and second pairs of apertures.
Therefore, it is an object of the invention to provide a locking pin simple in design and use for mechanically locking at least two parts.
It is a further object of the invention to provide such a pin which is of compact design.
It is another object of the invention to provide such a pin which may be easily installed without the use of special tools.
It is yet another object of the invention to provide a pin which is self-fitting and self-locking.
It is a further object of the invention to provide such a pin which prevents inadvertent removal and unlocking.
It is yet another object of the invention to provide a twist pin which cannot be released without imparting a twisting motion.
Other objects and advantages of the invention will be apparent from the following description, the accompanying drawings and the appended claims.
REFERENCES:
patent: 1625303 (1927-04-01), Fenton
patent: 1799934 (1931-04-0
Biebel & French
Holdren Brothers, Inc.
Nicholson Eric K.
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