Suture needle abstract
A method for forming a suture-receiving hole in an eyeless suture
needle. An oxidation resistant needle material and a heat resistant
pressing tool are provided. The base end of the needle is heated
to a temperature near its melting point and the heat resistant perforating
tool is pressed into the base of the needle to form the desired
suture-receiving hole. As an alternative, a preliminary hole can
be formed in the base end of the needle material before the perforating
tool is pressed into the hole as the final finishing step. Other
variations include rotating or vibrating the perforating tool as
it is pressed into the base end of the needle.
Suture needle claims
1. A method of forming an eyeless suture needle having a tapered
end, an intermediate portion, and a base end, the base end having
a hole, said method comprising: providing a needle material having
oxidation resistance; providing a heat resistant pressing tool having
a melting point higher than that of the needle; positioning the
needle in a holder with the base end of the needle extending beyond
the holder; providing a tubular restraining tool having an inner
diameter larger than the outer diameter of the needle to surround
the base end of the needle; heating the base end of the needle to
a temperature near its melting point; pressing the heat resisting
perforating tool into the base end of the needle material while
the base end of the needle material is near its melting point to
form a hole and an enlarged circumferential outer surface defined
by the interior of said tubular restraining tool; and cutting off
part of the enlarged circumferential surface to provide a needle
of uniform outer diameter at its base end and intermediate portion.
2. The method for an eyeless suture needle as claimed in claim
1 including the step of boring a preliminary hole in said needle
before the base end of the needle material is heated to near its
melting point and before the pressing step.
3. The method of forming an eyeless suture needle as claimed in
claim 1 or 2 including the step of rotating the perforating tool
as it is pressed into the base end of the heated needle material.
4. The method for forming an eyeless suture needle as claimed in
claim 2 wherein the boring step for the preliminary hole is performed
by laser processing.
5. The method for forming an eyeless suture needle as claimed in
claim 2 including the step of contacting the inner wall surface
of the preliminary hole with a rotating perforating tool to impart
unevenness to the inner surface of the hole based on the flow of
material formed in the direction of the wall surface by rotating
and contacting the heat resisting perforating tool to the inner
wall surface of the hole while the preliminary hole is heated to
near the melting point, and after the preliminary hole is bored
in the base end of the needle material.
6. The method for forming an eyeless suture needle as claimed in
claims 1 2 or 5 wherein a round rod made of a material selected
from the group consisting of tungsten, molybdenum, hard metal, and
tungsten rhenium is used for the heat resistant perforating tool.
7. The method of forming an eyeless suture needle as claimed in
claims 1 2 or 5 wherein the heating step includes heating the
base end of the needle material to 1000.degree.-1600.degree. C.
by conducting electricity to the needle material and the perforating
8. The method for forming an eyeless suture needle as claimed in
claims 1 2 or 5 wherein the heating step includes heating the
base end of the needle material to 1000.degree.-1600.degree. C.
by means of a flame.
9. The method for forming an eyeless suture needle as claimed in
claim 1 or 2 including the step of vibrating the perforating tool
as it is pressed into the base of the needle material.
10. The method for forming an eyeless suture needle as claimed
in claim 2 wherein the boring step for the preliminary hole is
performed by electron beam processing.
Suture needle description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a method for forming a suture-receiving
hole in an eyeless suture needle characterized in that a hole is
formed in the base end of a needle made from an oxidation resisting
material, and more particularly to a method for forming a suture-receiving
hole in an eyeless suture needle characterized in that a hole is
formed by pressing a heat resisting perforating tool in the base
end, after the base end of the needle material made of an oxidation
resisting material was heated to near melting point.
2. Description of the Prior Art
The usual methods for forming a suture-receiving hole in an eyeless
suture needle include: (1) a cutting processing method for cutting
by a drill, (2) a weld processing method for welding a tubular member,
(3) a discharge processing method for processing by discharging
between electrodes in a liquid, and (4) special processing methods
for causing the sublimation of a material by using an instantaneous
high energy laser or electronic beam. However, all of the above
methods have various problems as illustrated below. Also, they have
a disadvantage in that it is difficult to cheaply form a hole having
good character combining threads with high precision at the basic
end of suture needle.
(1) The method for cutting a hole by use of a drill is difficult
in the case of needle materials of stainless steel, especially when
the hole is below 0.3 mm diameter, and cutting a deep hole of about
4-5 times the hole diameter becomes very costly in relation to the
price of the needle and the life of the drill and is impractical.
(2) In the method of welding of a tubular member, welding of a
tube to a thin solid material is very difficult, especially as the
thickness of the tube becomes thin. There is also a possibility
of failure the welding during the cutting process for the purpose
of removal of weld flash and also the determination of hole-depth
is complex and costly.
(3) In the discharge processing method, the processing speed is
slow, and provides a hole that becomes a larger tapered shape at
the bottom than at the inlet, and in a hole below 0.4 mm diameter
the processing liquid does not circulate and the processing is nearly
impossible. Naturally, attempts to make the electrode into a tube
have been performed, but unless the hole diameter is fully expanded
so that the processing liquid passes through a hole in the tube
on account of the blind hole, the hole remains without receiving
the processing and also this processing is unusuable.
In the processing method (4) using a laser, an electronic beam
and the like, wherein the material is heated instantaneously to
a high temperature by laser light or an electronic beam, there is
a fatal defect in that the shape of the hole is unstable and the
accuracy is poor, because of sublimation of the material.
SUMMARY OF THE INVENTION
The method in accordance with the present invention is a quite
new technique developed in consideration of these usual defects.
Specifically, because in the present method the base end of the
suture needle is heated to a given temperature, the method is concerned
in a middle processing method such as three processing methods,
that is, casting processing, hot forging processing and welding
processing are used respectively at the same time.
Namely, this method is a processing method for forming a hole by
making a perforating tool enter the base end of a needle, by pressing
mutually, as if butt welding. The base end of the needle material
is heated locally and instantaneously to or near the melting point,
while held against a round rod or the like (a perforating tool)
having a diameter corresponding to a desired hole size, and having
a high melting point in comparison with the needle material (but
the perforating tool has a good life at low temperature as much
as possible). Accordingly, the processing temperature is higher
than the hot forging temperature, and also is lower than the casting
temperature which is carried out at a high temperature above the
melting point, and becomes the temperature of butt welding or a
little lower temperature than that temperature. Also, the processing
power is not as large a power as in hot forging, but is not a power
such as processing power "O" flowing in by dead load as
in the case of casting. The processing power becomes nearly equal
to or somewhat larger than the power used in butt welding, however
the processing purpose is not to form a melting junction, and is
closer to casting and hot forging and forming of materials without
entirely deforming fusion of the tool.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1-FIG. 4 are cross-sectional views in which the steps of the
method of the present invention are shown in order.
FIG. 5 is a perspective view of the finished suture needle.
FIG. 6 is a simple diagram of apparatus for performing the method
of this invention.
FIG. 7-FIG. 8 are cross-sectional diagrams of other examples.
FIG. 9 is a diagram of other apparatus.
FIG. 10-FIG. 11 are cross-sectional diagrams of another suture
needle and showing the installation of the thread.
FIG. 12 (a), (b) are diagrams of another example of a suture needle.
DETAILED DESCRIPTION OF THE DRAWINGS
Referring now to a specific embodiment in accordance with this
invention as shown by the drawings, in FIG. 1-FIG. 5 1 is a needle
made of stainless steel, 2 is a holder of needle 1 3 is an outer
circumferential restraining tool of tubular shape capable of preventing
the base end of needle 1 from deforming, 4 is a heat resisting performating
tool. In performing the method of the present invention, the base
end of needle 1 is first heated to near the melting point, thereafter
a perforating tool 4 is forcibly pressed in the base end of needle
1 at the time of this state, perforating tool 4 is extracted and
a hole 5 is formed in the base end of said needle material 1. A
projecting portion formed on the outer circumferential surface of
the base end on account of the formation of this hole 5 is cut off.
An eyeless suture needle 6 having a hole 5 in the base end can be
manufactured by curvedly processing the needle 1 to a prescribed
In carrying out the method of the present invention, various oxidation
resisting materials can be used for the needle material 1 and in
the case of steel, the following stainless steels are especially
13 Cr Stainless Steel (13% Cr) (Martensite system)
Standard SUS 410420 . . . melting point 1430.degree.-1530.degree.
18-8 Stainless Steel (18% Cr, 8% Ni) (Austenite system)
Standard SUS 304 302 . . . melting point 1400.degree.-1450.degree.
Precipitation hardening stainless steel
Standard SUS 630-17-4 PH stainless (17% Cr, 4% Ni, 4% Cu)
Standard SUS 631-17-7 PH stainless (17% Cr, 7% Ni, 1% Al)
Melting point . . . 1400.degree.-1500.degree. C.
With regard to the material used for perforating tool 4 in the
aforesaid example, substances having a high melting point such as
the following are considered.
______________________________________ Young's Melting Electrical
Modulus Symbol Point C Resistance kg/cm ______________________________________
Tungsten W 3410 .+-. 20 5.5 35 Molybdenum Mo 2625 .+-. 50 5.17
42 Carbon C 3700 .+-. 100 1375 0.5 Tantalum Ta 2996 .+-. 50 12.4
19 Osmium Os 2700 .+-. 200 9.5 57 Ruthenium Ru 2500 .+-. 100 7.6
42 Rhenium Re 3180 .+-. 20 19.3 47 Hard Metal 3500 46-63 Ceramic
BN 3000 5-10 Tungsten- W--Re 3300 Rhenium ______________________________________
When the present inventor put the above materials to the test,
Tungsten, Molybdenum, Hard Metal and Tungsten-Rhenium having a high
melting point and a comparatively high Young's Modulus were found
to be effective.
In the above experimental example, when the base end of needle
1 is heated to near the melting point (1400.degree.-1530.degree.
C.), a method for heating by flame, a method based on high frequency
induction heating, a method for conducting and heating the needle
1 and the tool 4 (in this conducting and heating method, the electrical
resistance of tool 4 should be small), and the like, are effective.
The experimental examples of the present invention will be illustrated
in detail as follows:
As shown in FIG. 6 the needle 1 is made of 0.6 mm diameter SUS
304 stainless steel and is maintained by the holder 2 while a tip
of tool stand 9 having a roller 8 is projected and is provided with
the tungsten round linear tool 4 of 0.33 mm diameter and pressed
by the pressing spring 7 at 150-200 g pressure. When a voltage of
0.7 V is connected with the needle 1 and the tool 4 an electrical
current flows, and the base end of needle 1 is heated to 1200.degree.-1300.degree.
C. Tool 4 enters the base end of needle 1 by the operation of press
spring 7. When the tool 4 advances to a certain position, a limit
switch 10 operates and the voltage becomes zero. When the base end
of needle 1 begins to cool gradually, the tool stand 9 is pulled
back in the rear and the hole 5 can be formed by pulling out the
tool 4 from the base end of the needle 1.
In carrying out the present example, heating temperatures on the
base end of needle material 1 were tested by means of three steps,
that is, 1000.degree.-1100.degree. C. (Voltage 0.55 V), 1200.degree.-1300.degree.
C. (Voltage 0.7 V) and 1400.degree.-1450.degree. C. (Voltage 0.9
V), and the life of tool 4 is longer and the shape of the hole 5
of needle 1 is favorable in the case of 1200.degree.-1300.degree.
When the conditions are the same as in Example 1 except that the
voltage after the operation of limit switch 10 is changed from zero
to 0.4 V, the life of tool 4 is longer than in the case of Example
When the conditions are the same as in Example 1 and the tool 4
has entered the base end of needle 1 while the tool 4 installed
on the tool stand 9 is rotated at 500 r.p.m., the life of tool 4
is longer than in the case of Example 1 and shortens the perforating
A laser light is used on the base end of needle 1. A preparatory
hole 11 of 0.25 mm diameter and 1.6 mm depth as shown in FIG. 7
is bored, and when the conditions are the same as Example 3 a hole
forming process is performed with 0.65 V voltage and 1200.degree.-1300.degree.
C. temperature of the base end of needle 1 the tool 4 can be pressed
in the preparatory hole 11 with very small power and the base end
of needle 1 is not deformed. The resulting hole 5 can be obtained
as nearly a true circle as shown in FIG. 8 and further more the
life of tool 4 can be lengthened more than in the above-mentioned
A needle 1 made of 0.6 mm diameter SUS 304 stainless steel is maintained
by the holder 2 as shown in FIG. 9. A preparatory hole 11 of 0.25
mm diameter and 1.6 mm depth is bored in the base end of needle
1. A tungsten wire of 0.33 mm diameter is used for the tool 4 and
the tungsten wire rotates at 500 r.p.m. The base end of needle 1
is heated to 1200.degree.-1300.degree. C. by means of burner 12
and the tool stand 9 chucked with tool 4 advances at a speed of
3 mm/sec. by driving the motor 13. The tool 4 simply enters the
preparatory hole 11 of needle 1 and a hole 5 of a nearly true circle
can be formed in the needle 1. The life of tool 4 can be lengthened
This condition is quite identical as in Example 5 but the formation
of hole 5 is performed at the same time that an ultra sonic vibration
is applied to the tool 4 and without rotation of the tool 4. The
formation of hole 5 is more effective than in the case when the
tool 4 is not moved, however as compared with the case when the
tool 4 is rotated, the present Example is observed to be inferior
in the shape of the hole 5 and the life etc. of tool 4.
The needle 1 is of 0.8 mm SUS 304 stainless steel and a hole of
0.47 mm diameter is completed in the needle material with drill
and laser light by means of an experimental apparatus as shown in
FIG. 9. The tool 4 which is composed of 0.47 mm diameter tungsten
wire, is rotated at 500 r.p.m. as the needle material 1 is heated
to 1400.degree.-1500.degree. C. by the burner 12. The tool 4 is
inserted into the hole in the needle material 1 with speed of 3
mm/sec. When the base end of needle 1 containing the hole is divided
into two parts lengthwise and the inner wall surfaces are observed
through a microscope, the inner wall surfaces according to the drill
hole and the laser hole are nearly a mirror surface, while a spiral-shaped
uneven X produced by a stream of material at high temperature has
been formed at the inner wall surfaces as shown in FIG. 12a (drill
hole) and FIG. 12b (laser hole), as those in FIGS. 3 4 and 5.
A thread is inserted into the hole 5 turning out this state and
the hole 5 is subjected to a caulking processing. Subsequently,
as a result of measuring the extracting power of the thread, a result
indicating large extracting power is obtained, namely an average
increase of 45% in the drill hole and an average increase of 90%
in the laser hole by processing the inner wall surface, as compared
with a hole having no processing in the inner wall surface.
When the present method is carried out as mentioned above, and
the principle under which an uneven X is formed automatically in
the inner wall surface of the hole 5 of needle 1 (suture needle
6) is considered, when the perforating tool 4 is inserted into the
needle 1 heated to near the melting point as the perforating tool
4 rotates, the tool 4 comes in contact with the substance so that
the needle 1 turns into the states of exactly hard paste and proceeds
as this paste-like material is rubbed, and in the inner wall surface
of the hole 5 formed by the tool 4 an uneven X remains in that
condition together with dropping the temperature of needle material
Since the method in accordance with the present invention is a
method that involves a perforation performed by making forcibly
a heat resisting perforating tool enter the base end while the base
end of the needle material is heated to near the melting point of
the needle material, the method can be performed simply and reliably.
A hole with good capability for attaching thread is provided, as
opposed to that of the prior art wherein the operation of the prior
art process is complex and the work efficiency is poor. In the drill
cutting method, pipe welding processing method, electrical discharge
perforation method and laser, electron beam processing method and
the like in the prior art, if the prior art method is utilized as
the secondary processing method of perforation by rotating the tool
4 the method can be considered as a method for forming the inner
wall surface of the hole, and the tool employed can be a wire of
heat resisting material, and the method is inexpensive and can remarkably
lengthen the life of the hole. Accordingly, the method of the present
invention is suitable to the processing of stainless needles (especially
austenite system), the processing of which was previously considered
to be relatively difficult. In the method of the present invention,
when the austenite system stainless steel or the precipitation hardening
type stainless steel is used without conducting a quench hardening
processing of the whole needle at the end of the process, since
the needle material is heated to near the melting point at the time
of processing, the base end softens (for example the whole needle
makes a hole portion Hr 200 against Hr 500), and at the time of
caulking the caulking power is small and the base end is easy to
fit with the thread and the thread extracting power becomes large.
Heretofore the deficiency resulted from the inner part, but this
now has a character in which the deficiency is not produced. Furthermore,
when the present invention is carried out, as shown in FIG. 10
a suture needle in which an outer diameter of the base end of the
needle 1 around this hole 5 is larger than other portions, the suture
needle 6 constituted in this manner is utilized positively with
the state as it is, after the thread 14 is inserted in the hole
5 by means of caulking this larger diameter portion, as shown in
FIG. 11. A special suture needle such that an outer diameter of
the base end of the suture needle becomes nearly equal to the outer
diameter of thread 14 can be manufactured automatically by omitting
the process in the midst of carrying out the present method. Moreover,
in the case of rotation of the tool when the present invention is
carried out, the unevenness and the oxidized adhesive in accordance
with a compulsory stream of material at high temperature in the
inner surface of the hole can be formed, and therefore the installing
capability of the thread to the hole can be raised remarkably. The
formation of the inner wall surface can be utilized independently
for the secondary processing of the usual method, and the present
method has various characteristics as mentioned above.