Method for forming threadings in a bushing which is used to secure a hose therein

A method is provided for forming threadings in a bushing and includes (a) providing a die; (b) extruding a tubular bushing made of metallic material into the die; (c) providing a punch member to punch into the bushing to form a first threading therein; (d) pressing down the bushing along the die and again providing the puncher member to punch into the bushing to form a second threading therein; and (e) repeating the step (d) until a plurality of predetermined threadings are formed in the bushing.

BACKGROUND OF THE INVENTION 
1. Field of Invention 
The present invention relates to a method for forming threadings in a 
bushing which is used to secure a hose therein. 
2. Related Prior Art 
A conventional method for forming threadings in a bushing is shown in FIGS. 
13-15. However, in this manner, the pitches defined between any adjacent 
two of the threadings formed in the bushing are not equal. 
There will be a more complete and sufficient illustration in the detailed 
description of the preferred embodiments, concerning the conventional 
method for forming threadings in a bushing. 
The present invention has arisen to mitigate and/or obviate the 
above-mentioned disadvantages of the conventional method for forming 
threadings in a bushing. 
SUMMARY OF THE INVENTION 
The primary objective of the present invention is to provide a method for 
forming threadings in a bushing so as to form a plurality of threadings 
each of which has an equal pitch with each other. 
In accordance with one aspect of the present invention, there is provided a 
method for forming threadings in a bushing which is connected between a 
hose and a hose connection so as to secure the hose in the bushing, the 
method comprising (a) providing a die; (b) extruding a tubular bushing 
made of metallic material into the die; (c) providing a punch member to 
punch into the bushing to form a first threading therein; (d) pressing 
down the bushing along the die and again providing the puncher member to 
punch into the bushing to form a second threading therein; and (e) 
repeating the step (d) until a plurality of predetermined threadings are 
formed in the bushing. 
Further objectives and advantages of the present invention will become 
apparent from a careful reading of the detailed description provided 
hereinbelow, with appropriate reference to the accompanying drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
For a better understanding of features and benefits of the present 
invention, reference is made to FIGS. 13-15, illustrating a conventional 
method in accordance with the prior art. Referring to FIG. 13, a 
conventional method is provided for forming a plurality of threadings 71 
in a bushing 70 which is connected with a hose connection 60 and is 
threadedly engaged with a hose 62 in which a connecting tube 61 is sealed, 
so as to secure the hose 62 in the bushing 70. Referring to FIG. 14, this 
conventional method comprises providing a cutting tool 80 with one blade 
to serially cut out a plurality of threadings 71 in the bushing 70. In 
this manner, the bushing 70 is continuously and repeatedly worked by the 
blade of the cutting tool 80 to form the plurality of threadings 71, so 
easily deforming the blade of the cutting tool 80 after long-term 
utilization during the working process and causing great cost in 
manufacturing. In addition, the pitches defined between any adjacent two 
of the threadings 71 are not easily in concert. Referring to FIG. 15, this 
method further comprises providing a cutting tool 81 with multiple sharp 
blades to form a plurality of threadings 71 at a time. In this manner, the 
cutting tool 81 will encounter great resistance due to friction, so easily 
wearing out the sharp blades thereof. In addition, the depth of each of 
the threadings is shallow. 
Referring to FIGS. 1-12, and initially to FIG. 12, a method in accordance 
with the present invention is provided for forming a plurality of 
threadings (not labeled) in a bushing 41 which is connected with a hose 
connection 60 and is threadedly engaged with a hose 62 in which a 
connecting tube 61 is sealed, so as to secure the hose 62 in the bushing 
41. Referring to FIG. 1, the method comprises (a) providing a die 20; (b) 
extruding a tubular bushing 41 made of metallic material into the die 20; 
(c) providing a punch member 10 to punch into the bushing 41 to form a 
first threading 411 (not shown) therein; (d) pressing down the bushing 41 
along the die 20 and again providing the puncher member 10 to punch into 
the bushing 41 to form a second threading 412 therein; and (e) repeating 
the step (d) until a plurality of predetermined threadings are formed in 
the bushing 41. 
Again referring to FIG. 1, the die 20 longitudinally defines an upper first 
passage 21 and a lower second passage 23 therein which communicate with 
each other, the first passage 21 has a diameter greater than that of the 
second passage 23 and a tapered surface 22 is formed therebetween. The 
bushing 41 has an outer diameter equal to the diameter of the first 
passage 21. The punch member 10 comprises a punch head 11 having an 
extension portion 111 protruding from an underside thereof, the punch head 
11 has a diameter equal to an inner diameter of the bushing 41 and greater 
than that of the extension 111. 
Now, a detailed description of this method is illustrated. Referring to 
FIGS. 2 and 3, a cross slide 30 is slidably mounted on an underside of the 
die 20 for biasing against the bushing 41 therein, the cross slide 30 has 
a first end and a second end and comprises four flat surfaces which are 
arranged in a stepwise fashion with an uppermost first flat surface 301 at 
the first end of the cross slide 30 and a lowermost fourth flat surface 
304 at the second end thereof, and a distance defined between adjacent two 
of the flat surfaces is equal. The first flat surface 301 is originally 
biased against the underside of the die 20, then the bushing 41 is 
extruded into the die 20 via the first passage 21 thereof by a pressing 
block 50 and is compressed in the second passage 22 so as to form a 
configuration as shown in FIG. 2, the pressing block 50 is then removed. 
The punch head 11 of the punch member 10 is then punched into the interior 
of the bushing 41 so as to form a first threading 411 (see FIG. 3) therein 
due to a gap defined between the punch head 11 and the extension 111 
thereof. 
Referring to FIGS. 4 and 5, the cross slide 30 is displaced forward with a 
second flat surface 302 thereof disposed under said die 20, the bushing 41 
is again extruded by the pressing block 50 to move downwardly with an 
underside thereof abutting against the second flat surface 302 so as to 
form a configuration as shown in FIG. 4, the pressing block 50 is then 
removed. The punch head 11 of the punch member 10 is then punched into the 
interior of the bushing 41 so as to form a second threading 412 (see FIG. 
5) therein. In a same manner, referring to FIGS. 6 and 7, the bushing 41 
is biased on a third flat surface 303 of the cross slide 30, thereby being 
formed a third threading 413 thereon, and referring to FIGS. 8 and 9, the 
bushing 41 is biased on the fourth flat surface 304 of the cross slide 30, 
thereby being formed a fourth threading 414 thereon. It is to be noted 
that, the threadings formed in the bushing 41 are spaced at an equal 
distance and the pitch between adjacent two of the threadings in the 
bushing 41 is equal to the distance between adjacent two of the flat 
surfaces of the cross slide 30. 
Referring to FIGS. 10 and 11, the fourth flat surface 304 of the cross 
slide 30 defines a hole 312 therein which has a diameter greater than the 
outer diameter of the bushing 41. When a plurality of predetermined 
threadings, e.g. four, are formed in the bushing 41, a clamp device 80 
(see FIG. 10) is provided for clamping a second tubular bushing 42 to be 
forced into the die 20 by the pressing block 50 (see FIG. 11) so as to 
eject the bushing 41 from the die 20 via the hole 312 of the cross slide 
30, thereby continuing forming a plurality of predetermined threadings in 
the bushing 42 and the ongoing procedure is thus accomplished. Therefore, 
the bushing 41 is formed with four threadings therein which have an equal 
pitch with each other. 
It should be clear to those skilled in the art that further embodiments of 
the present invention may be made without departing from the teachings of 
the present invention.