Fluid sprinkling – spraying – and diffusing – Flow line or nozzle attached or carried handgrip or handle – Pistol grip type
Reexamination Certificate
1999-07-09
2001-04-10
Douglas, Lisa Ann (Department: 3752)
Fluid sprinkling, spraying, and diffusing
Flow line or nozzle attached or carried handgrip or handle
Pistol grip type
C239S600000, C285S286100, C285S290100, C285S293100
Reexamination Certificate
active
06213411
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an inlet of blow gun, and more particularly to a metal inlet combined in the plastic blow gun by injection molding the inlet tightly without it being loose and without leakage when it is in use.
2. Prior Art
In accordance with the conventional plastic blow gun, as shown in
FIG. 1
, the inlet
11
is provided with an internal screw thread
111
for connecting with a quick connector providing the compressed air from the compressed air source. So, the inlet
11
and the internal screw thread
111
are molded with the blow gun, integrally. However, there are some shortcomings existing in this structure, as follows:
1. Due to the physical phenomenon of heat-expansion and cool-shrinking, the cooling of the plastic after stripping from the high-temperature die, the internal screw thread
111
becomes distorted, or the teeth are contracted, so that the tightness of threaded engagement therewith is poor, even causing leakage.
2. Because the internal screw thread
111
is plastic, it is not rigid enough, so that the threaded engagement of the connection will loosen over time, and sometimes the surface of the internal screw thread
111
will be stripped off, causing leakage.
3. During long term use under high pressure with compressed air, the fatigue resistance of the plastic at the internal threaded portion is so short that the service life of the blow gun is affected.
4. Because the plastic has a poor strength and lack of rigidity, the internal screw thread
111
often is cross-threaded when screwing on the quick connector, causing the internal screw thread
111
to be damaged, even causing the inlet
11
to break.
For overcoming the above-mentioned shortcomings, a new blow gun has been brought out on the market, in which a reformed metal inlet
20
is embedded into the trunk of the blow gun, as shown in FIG.
2
. The inlet
20
is presented to a cylinder having a ratchet striated outside surface, and a smaller diameter front tip end for embedding an O-ring
22
, and a threaded internal screw hole
23
. Referring to
FIG. 3
, a stepped hole
12
is formed at the intake position for embedding the metal inlet
20
therein. The end of the stepped hole
12
is sealed with the O-ring
22
for preventing the compressed air from leaking. Pressing the inlet
20
embeds the ratchet striated surface
21
into the stepped hole
12
for retaining the metal inlet
20
in place, so that the quick connector threads into the metal inlet
20
to overcome the shortcomings of the plastic inlet.
As the embedded inlet
20
is pressed into the plastic blow gun
10
, it has an engaging depth of 0.2-0.3 mm, and the meshing strength is thereby very limited. When screwing on the quick connector, and for avoiding leakage and looseness, the threaded joint is often over-torqued with a large turning effort. Often the torque is sometimes so large that the engaging joint between the ratchet striated surface
21
and the plastic trunk of the blow gun causes the metal inlet
20
to slip off and to lose relative function. On the other hand, when pressing the metal inlet
20
into the plastic trunk of the blow gun
10
, the central axis of the inlet
20
is often misaligned, so that the O-ring
22
cannot seal the end of the stepped hole well, with the result that the compressed air will leak during long term use under high pressure. Therefore, the service life of this kind of blow gun is not long enough, and the production cost cannot be easily reduced.
OBJECTS AND SUMMARY OF THE INVENTION
It is therefore a main object of the present invention to provide a metal inlet serving as a core bar embedded into the plastic blow gun during injection molding, so that the joint between them has more strength, thereby overcoming the poor connection and leakage problems of the prior art. Meanwhile, the strength of the teeth of the internal screw is increased.
For achieving that object, the metal inlet core provided by the present invention, a polygonal or deeper ratchet striated outside surface, meshes with the plastic trunk of the blow gun with more strength and more tightly, as it is integrally molded with the blow gun. It can resist greater torque, to prevent the metal inlet core from slipping off. It not only reduces the production cost, but also increases the service life of the blow gun.
For increasing the engaging area of the surface and the joint strength, the present invention provides the metal inlet with a polygonal or a ratchet striated outside surface in which a groove ring is formed transversely in the middle of the polygonal or the ratchet striated surface.
REFERENCES:
patent: 3599876 (1971-08-01), Kyburg
patent: 3811622 (1974-05-01), Blatt
patent: 3814329 (1974-06-01), Clark
patent: 4867380 (1989-09-01), Sibbertsen
patent: 5286001 (1994-02-01), Rafeld
patent: 5832974 (1998-11-01), Jou
Douglas Lisa Ann
Rosenberg , Klein & Lee
LandOfFree
Inlet of blow gun does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Inlet of blow gun, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Inlet of blow gun will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2537765