MXPA97004181A - Reception of needle with current consta - Google Patents

Abstract

A constant current annealing device is described for annealing a wire or surgical needle, the device includes amplitude and time setting devices, such as thumb-operated wheel switches, a constant current source is connected to the fixation device current, the constant current source is interruptible, through a switch for example, in response to a time regulation signal to provide a constant current for a predetermined duration, a pair of separate separate electrodes are clamped on the needle and an interrupting device is connected between the constant current source and the pair of electrodes, the voltage drop across the interrupting device varies to compensate for load variations, thus maintaining the annealing current constant in the annealing mode; annealing off mode, when no current is supplied to the needle, the interrupting device derives a residual current away from the electrodes, the time setting device includes a programmable logic controller (PLC) and a solid state relay to provide an accurate time regulation signal, a current measuring and monitoring device is connected to another PLC, which turns off the annealing device after a predetermined number of alarms or after the current amplitude is diverted by a predetermined amount

Description

NEEDLE NEEDLE WITH CONSTANT CURRENT BACKGROUND OF THE INVENTION FIELD OF THE INVENTION The present invention is directed to a device and method for heating ßl and continuous wire annealing, high current and high speed electric resistance, and more particularly to a device and method of annealing surgical needle with current constant.

Description of the Prior Art Surgical needles are formed from cut wires to provide needle pieces. After processing one end of the needle piece to a desired needle shape, the excess portion of the needle piece is cut. Before cutting the excess needle piece, the portion that will be cut is annealed or heated. This softens the portion that will be cut to facilitate cutting and further processing, such as forming a channel or drilling a hole in the soft portion for suture insertion. The annealing can be carried out using conventional furnace flames and resistance heating or induction heating. The patent of E.U.A. No. 4,295,033 (Lindgren) describes an annealing furnace. Conventional annealers suffer from a number of disadvantages, such as limited precision, consistency and speed. Some flame anneakers are limited to rack or manual operations. Open flames, including a pilot light, increase the risk of accidents, oxidize the needle and deposit carbon and soot on the needle. In addition, heat collectors may be required to confine the annealing zone. Heat transfer from flame annealing is inconsistent due to variations in flame temperature, gas pressure and flame application time or movement speed. Moreover, there is no feedback or indication of an adequate or inadequate annealing. In addition, the annealing speed is low, thus reducing the overall emission of needle manufacture. Various types of flame annealing have been used to anneal a specific portion of a wire or needle parts. Flame recoilings can be used in a continuous needle forming process in which the needle pieces are mounted on a carrier strip 15, as shown in Figure 1. In alternate form, the flame anneals are used with an intermittent procedure of needle formation. In intermittent needle-forming procedures, needles are formed in batches. A batch of needle pieces is manually arranged on a workpiece holder or frame for processing. The workpiece holder can be an integral part of the annealing mechanism. Alternatively, the workpiece holder may have its own support mechanism, which is attached to the annealing mechanism. An engine can control the exact positioning of the needle parts mounted on the frame. The needle parts mounted on the frame can be presented to several operations that require the organized presentation of needle parts or needles. Such operations include sharpening, channeling, bending, cutting of the needle piece, perforation, annealing, needle tip formation, needle body formation, needle passivation , defatting, electro-polishing, washing, rinsing, drying and coating with a lubricating substance, such as a mixture of silicon for example. Annealing a portion of the needle piece before cutting it can be carried out by introducing a flame and moving either the flame or the frame in a controlled manner. A type of flame annealing known as a channel flame annealing uses a long, fixed, continuous burner tube. The fuel for the flame can be natural gas or bottled (propane or butane) mixed with air or compressed air. The burner tube can be a tube a normal conduit with a series or rows of holes drilled to provide flames. The larger holes provide a wider flame to anneal a larger portion of the needle pieces. A time regulator controls the duration of the flame, igniting and extinguishing the flame or controlling the duration of the needle pieces in a continuous flame. This controls the transfer of heat to the portion of the needle piece or the annealing zone. A heat sink is used to confine the annealing zone. The duration of the flame can be controlled by the electric control of a gas solenoid, which when open, uses a pilot light or a piezoelectric crystal to ignite the entire burner. Alternatively, the duration of the needle pieces in the combustion zone can be controlled by moving the frame in and out of the combustion zone using conventional mechanical means. For example, a slide receiver pivot mechanism is used to lower the needles mounted on the slide in a position of engagement with the combustion zone. The duration of the coupling can be preset using a conventional time control mechanism. The establishment of the time control can be achieved by mechanical means, such as the coupling of rotating means, which applies a rotating action to the pivot receiver mechanism of the slide. The time control mechanism, via an air actuating means, could also allow the pivotal movement of the slide receiver pivot mechanism to be transferred through a cylinder means. This provides the adequate duration of the coupling of the needle parts with the combustion zone. This annealing channel flame can be automatic, where a microswitch detects the presence of the frame, drives cylinders that hold and locate the frame that has pieces of needle on it and starts automatically, controls the time and stops the annealing cycle. In another flame annealing, known as a precision flame annealing, the same burner is moved in and out of the annealing areas of a batch or individual needle pieces mounted on the frame. The duration of annealing is controlled by a conventional time control mechanism. The burner can be a single small port burner or a multi port long burner. The small burner can transport the needle parts mounted on the frame to heat one needle at a time in a very precise area. The heat transfer is controlled by the speed of the passage. The burner can be moved by conventional means such as a linear motor, a motor driven ball screw or a time control screw, a rack and pinion motor or an air cylinder. This annealing of the flame of precision can be semi-automatic, where the loading of the frame activates the annealing cycle. In higher speed annealing, propane or similar fuels mixed with air may not heat sufficiently. Instead, oxygen or other flammable gases? e.g., hydrogen, can be mixed with conventional fuels or methane, to obtain a more consistent and higher heating temperature. Despite the increased speed, the flame anneals are still slow and typically limited to 20 parts per minute. Instead of mounting the needle parts on a slide or frame, the needle parts can be mounted on the carrier strip 15 shown in Figure 1. This increases the annealing speed and the needle production output. For a stationary flame, the needle pieces mounted on the strip can be moved or directed continuously, stopping briefly inside the flame. The limiting factor is again the consistency and repeatability of the heat transfer. Using intense heat, annealing time control is critical for proper annealing. Due to the high intensity heat, even slightly long annealing time leads to burning or melting of the annealing portion of the needle pieces. The precise regulation of the gas pressure or the flame temperature is necessary. This is difficult to achieve and may not yet lead to a repeatable annealing. To improve annealing, a hydrogen gas generator is used and a small amount of alcohol is added as an inflammation suppressant. Conventional flame collectors suffer from slow speed. To increase the annealing speed, laser flame annealing has been used. High speed laser flame anneals provide a hot flame in a fairly precise annealing zone without the need for heat collectors. However, such anneals require a complex fuel supply and have some deviation in the heat output. Other disadvantages include lack of feedback, the presence of open flames and difficulty in obtaining repeatability. Resistance anneals heat the annealing zone by passing a current through it. The current is passed through a pair of separate electrodes fastened to two ends of the annealing zone. This current heats the portion of wire 25 (FIG. 1) located between the clamped electrodes up to the annealing temperature. The heat released to the annealing zone portion of the wire is equal to the time product and the square of the current as shown in equation (1): H = 12 T (1) where: H is total heat; I is current; and T is time or duration. Conventional resistance annealers do not suffer from some of the disadvantages of flame annealing. For example, the accumulation of soot and carbon is eliminated. The annealing has double grip contacts that are operated by cam. The annealing cycle is activated by cam. However, conventional resistance annealers will operate at low speed, such as 10 parts per minute, and are limited for use with small wire sizes. This is because conventional resistance annealers have a maximum current of approximately 20 amps. In addition, no feedback is provided and proper annealing is manually verified, e.g., by observing the color of the annealed wire. The color of the annealed portion ranges from gold, red, blue to silver. The determination of the adequate character of annealing by observation is imprecise and subjective. In addition, the current is monitored using an oscilloscope and adjusted manually with a potentiometer. The duration of the current is determined using an electromechanical time controller having a resolution of 0.1 seconds. Such annealers are inaccurate, slow and require the intervention of an operator. Conventional resistance annealers are complex, can not operate at high speed and suffer from inadequate precision as well as a high failure rate of annealed wires or needles. Other conventional resistance annealing devices measure the voltage or temperature of annealed wire to adjust the current through it. A resistance annealing device which measures the temperature is described in the U.S. patent. No. 4,409,042 (Dornberger). Such anneals require complex reflectors and are not suitable for high speed annealing. The speed is limited due to the response time of the temperature sensors. British patent application GB 2 091 002 (Ash) describes a wire annealing in which the resistance of the wire is measured as a representation of the temperature of the wire. The patent of E.U.A. No. 3,746,582 (Gentry) also discloses wire annealing, in which temperatures are controlled by varying the current through the separate contacts to heat the wire portion located between the contacts. Other strength annealing devices are described in U.S. Patent No. 3,842,239 (Ellinghausen), and the U.S. Patent. No. 3,962,898 (Tillmann). These annealers are not suitable for high precision and high speed annealing.

BRIEF DESCRIPTION OF THE INVENTION High speed annealing, e.g., at a rate of 120 parts per minute, requires high precision. At 120 parts per minute, the duration of each total annealing cycle is 0.5 seconds or 500 milliseconds (msegl.) This includes indicating the needle piece, holding the electrodes or contacts in it, turning on the current, applying the current during time desired (time control), and turn off the current.The mechanical actions of contact indication and clamping consumes approximately 75% of the available time of the annealing cycle.This leaves 1 / B seconds or 0.125 msec for real annealing. In this short annealing time, the heat release is critical since the duration and amplitude of the current must be precisely controlled.The conventional annealing devices can not release a precise repeatable current amplitude for a duration Precise at high speed.The current amplitude of conventional annealing devices varies due to changes in load or AC power line, contact wear and ntamination of the surface of the needle. Therefore, it is an object of the present invention to provide a constant current annealing device and a method that eliminates the problems of conventional resistance annealing. Another object of the present invention is to provide a resistance annealing device that supplies a constant current irrespective of changes in load or AC power line, contact wear or contamination of the needle surface. Another object of the present invention is to provide a resistance annealing device having a high current output for wide wire annealing. Another object of the present invention is to provide a resistance annealing device that performs precise annealing at high speed. Another object of the present invention is to provide an annealing device of resistance which has a rapid interruption response. It is also another object of the present invention to provide an annealing device of resistance which is safe to operate, and which has covered contacts and which does not have open flames. A further object of the present invention is to provide a resistance annealing device that allows high precision and repeatability from one annealing cycle to another. It is also another object of the present invention to provide a resistance annealing device that alerts operators to an inaccuracy in the annealing current amplitude and automatically stops annealing after a predetermined number of incorrect current readings, or when the current amplitude changes by a predetermined amount. These and other objects of the present invention are achieved by a constant current annealing device for annealing a wire or a surgical needle consisting of a reference circuit to set a desired type of annealing and current amplitude. The reference circuit includes a current-setting device that generates a d-current amplitude signal, and a time-setting device that generates a time-regulating signal. Illustratively, the amplitude and time setting devices are wheel switches operated by the thumb. A pair of separate electrodes are clamped on the needle. A constant current source is connected to the reference circuit and provides a constant current to anneal the needle. An interrupting device is connected between the constant current source and the pair of electrodes. The constant current source provides a constant current through the pair of electrodes when the interrupting device is in one position. In one embodiment, a voltage drop across the interrupting device varies in response to changes in a voltage drop across the needle so the annealing current flowing through the needle, Remains constant. In another embodiment, the interrupting device derives a residual current out of the pair of electrodes when the interrupting device is in another position. The constant current source is interchangeable, through a switch, for example, in response to a time control signal representing the set annealing current or time. This provides a constant current for the set annealing duration. The constant current source comprises a constant voltage generator q? E generating constant voltage in response to the fixed current amplitude. A power supply supplies the constant current, and is connected to a first terminal of a reference resistor. The second terminal of the reference resistor is connected to receive ßl constant voltage. This provides a constant voltage drop across the reference resistor, resulting in the generation of the constant current. The reference circuit includes a programmable logic regulator of time and a solid state relay having high rebound. The programmable logic controller of time controls the solid state relay to generate a time regulation signal. A current measuring device connected to one of the electrodes measures an amplitude of the constant current. The current measuring device can be a Hall effect transformer placed around a line connected to one of the electrodes. A visual indicator, such as a digital visual indicator, can be connected to the current measuring device to show an indication of the current amplitude. ür \ system programmable logic controller drives the programmable logic regulator of time to generate the time regulation signal when the electrodes are clamped in the wire. The programmable logic controller of time off switches off the constant current after which the measured amplitude is deflected by a predetermined amount or when a number of inappropriate indications exceeds a predetermined number. In this embodiment of the present invention, a method for annealing a surgical needle using a constant current annealing device comprises the steps of: a) setting a constant current amplitude and a current time, - (b) providing a constant current for the time set for the needle through an interrupting device; and (c) varying a voltage drop across the interrupting device in response to a change in the voltage drop across the needle. In the other embodiment, step (c) is replaced by interrupting the interrupting device to decrease a residual current while interrupting a switch to stop the generation of the current. The step of providing a constant current comprises the steps of: connecting a terminal of the reference resistor to a power supply, - generating a reference voltage using a reference voltage generator; and interrupting a switch to provide the reference voltage at another terminal of the reference resistor using an operating amplifier. Another step includes generating a current time regulation signal using a programmable logic controller of time regulation. Other steps may include: setting a current amplitude using a current amplitude setting device; setting the current time using a current duration setting device; hold a pair of separate electrodes on the wire or needle; generating an annealing signal from a system programmable logic controller indicating the compliance of the clamping; measure an amplitude of the constant current using a current detector; indicate a level of the amplitude of the current detected in a monitoring device; and stopping the annealing device when the indicated current level exceeds a predetermined level or when a number of inappropriate indications exceeds a predetermined number; BRIEF DESCRIPTION OF THE DRAWINGS The additional features and advantages of the invention will become readily apparent from a consideration of the following detailed description, set forth with reference to the accompanying drawings, which specify and show preferred embodiments of the invention, and in which like elements they are designated by identical references throughout the drawings; and in which: Figure 1 shows a perspective view of a needle piece mounted on a section of a conventional carrier strip as known in the prior art; Figure 2a shows a perspective view of a conventional needle having a channel as is known in the prior art; Figure 2b shows a perspective view of a perforated remote end of a conventional needle as is known in the prior art; Figure 3 shows a block diagram of a constant current resistive annealing according to the present invention and Figure 4 shows an outline of the annealing of Figure 3 according to the present invention.

DESCRIPTION DETAIL OF THE INVENTION Surgical needles and methods of manufacturing surgical needles are well known in the art. Surgical needles are formed from cut wires to provide needle pieces that are disposed on a carrier strip for transport to several stations of a continuous needle forming device. Such a needle-forming device is described in the U.S.A. No. 5,477,604, entitled "Process for rial? Facturing Taper Point Surgical Needles", issued December 26, 1995 and assigned to the assignee of the present application and contains matter related to the subject matter of the present patent application. The description of the patent of E.U.A. No. 5,477,604 is incorporated herein by reference thereto. Figure 1 shows a needle part 10 mounted on a carrier 15. The needle pieces 10 are processed, eg, heat treated to make the needle parts harder and tougher, and a sharp end 20 sharpened and shaped in? Na desired curvature. The processing of the needle pieces 10 includes annealing the proximal portions 25 of the needle pieces 10 to soften the portion 25 before cutting. Annealing portion 25 heats it to a temperature close to, but below a transformation temperature. The portion 25 is subsequently cooled slowly. This is commonly called as partial annealing. Partially annealing portion 25 softens the metal located in portion 25 up to point which retains some added strength and hardness from the previous heat treatments. The duration and annealing temperature of the needle part portion 25 before cutting should be precisely controlled to obtain a desired softening of the wire portion 25. The desired temperature deviation and annealing time results That portion 25 is very soft or very hard. Inadequate resistance of portion 25 causes failures during subsequent manufacturing steps or during use. Figure 2a shows a surgical needle 50 having a pointed distant end 55. The proximal end 60 is the portion 25 that has been annealed before cutting the needle part 10 shown in Figure 1. A channel 65 is cut within the end distant 60. A suture is placed in channel 65 and held in place by bending inward channel 65. Instead of channel 65, a hole can be drilled in the far end 60. Figure 2b shows a distal end 60 with a hole 70 therein. Surgical sutures can be fixed or mounted to the proximal ends 60 in various ways. A common way is to have a channel 65 formed in the proximal end of the needle 50 as shown in Figure 2a. The channel end is typically formed by means of a die in a needle 50 during the manufacturing process and consists of a cavity. When a tip or end of surgical suture is placed within the cavity 65, the end of channel 60 is hit with a given one or more times under pressure forcing the side walls of the channel to close tightly around the suture tip . This prevents the separation of the needle from the needle. The method of mounting a suture tip to the proximal end 60 of a needle 50 is known in the art as stamping. As shown in Figure 2b, another way in which a suture can be mounted to a surgical needle is by drilling a hole 70, called in the art as a blind hole, at the proximal end 60 of the needle 50. This can be done using conventional mechanical drilling devices or conventional laser drilling devices. The end or tip of a suture is then inserted into the perforated hole 70 and the proximal end section of the needle surrounding the blind hole 70 is stamped in a conventional manner by compressing with several conventional dies. Inconsistent and inadequate annealing of the proximal end 60 causes several problems. If the annealing occurs for a long time or releases excessive heat in the portion 25 to be annealed, then the portion 25 becomes excessively soft. A suture may not be properly maintained in the channel 55 or hole 70 of the proximal end 60 after stamping. The suture can be separated from the needle or the needle can be folded during processing, handling, or subse- quent use. If the annealing does not release sufficient heat to adequately soften the proximal end 60, then the hard or friable proximal end 60 may break during stamping. In addition, the hard proximal end 60 rapidly wears the cutting edges of tools, such as cutting dies, puncture tips and stamping tools. This requires frequent replacement of the tool and is cost. The cost increases not only due to the cost of replacing the cutting tool, but also due to the reduced production of the needle, for example, which results from the interruption of a continuous manufacturing process. The need for consistent annealing is even more apparent for needles produced in batches, rather than in a continuous manufacturing process in which destructive tensile strength assessments are carried out on a representative needle of the batch. It is essential that the annealing be controlled in a precise manner. By controlling the temperature, the duration and the cooling cycle of the annealing, a wide scale of metallurgical properties can be obtained, including the relative strength, hardness or ductility. Figure 3 shows an illustrative block diagram of a constant current resistive annealing device 100 in accordance with the present invention. The device 100 consists of at least reference circuit 162 for setting the duration and amplitude of the current applied during the annealing of a needle 135. As illustrated in FIG. 3, this reference circuit 162 includes two adjustable devices They have individual circuits to set the time and amplitude of annealing current. The first aj? Stable device is for setting the desired annealing current amplitude, known as? N current amplitude setting device 105, which may be a wheel switch operated by the thumb. The thumb-operated wheel switch 105 generates a preset signal to determine the current amplitude applied during the annealing step. This preset signal is euminietrated to a reference voltage generator 110. Illustratively, the reference voltage generator 110 generates a reference voltage Vrβf of 0 to 10 volts and is connected to the input of the n-3 capacitor amplifier. A potentiometer can be connected between the reference voltage generator 110 and the capacitor amplifier Al-3 to adjust the amplitude of the reference voltage Vr »f. The output of the Al-3 capacitor amplifier is connected to the input of another capacitor amplifier Al-4 through a switch 112. The Al-3, Al-4 decoding amplifiers have high input impedances and low output impedances to provide insulation . This keeps the voltage at the output of the Al-4 capacitor constant and prevents this constant output voltage from being susceptible to noise. The output of the capacitor amplifier Al-4 is connected to the input of a constant current source 115. The constant current source 115 comprises a constant voltage generator Al-1, which may be an amplifier of operation having inverting inputs and not inverters. The non-inverting input of the Al-1 operation amplifier receives an isolated and adjusted DC voltage (derived from the reference voltage Vrtf) from the capacitor output Al -4. The output of the operation amplifier Al-1 is connected to a constant current switch device 120. The inverting input of the operation amplifier Al-1 is connected to a terminal 18 of a reference resistor Rrtf. The voltage levels at both inputs of the Al-1 operation amplifier are the same. In this way, the DC voltage at the non-inverting input of the operation amplifier fll-1, (whose DC voltage is provided by the reference generator 110 through a potentiometer, and the capacitor amplifiers Al-3, Al-4 and the switch 112) is also provided to the node or terminal 18 through the inverting input of the operation amplifier Al-1. This reference voltage at node 18 remains constant regardless of the noise or changes in the output voltage of the Al-1 operation amplifier. The other terminal 3 of the reference resistor Rrβf is connected to a power supply PS1. The power supply PS1 supplies the constant current I used to anneal the needle 135. Illustratively, the power supply PS1 is a power supply of 125 amps and +12 vdc, which has a resolution of 10 milli-amps. The interrupting device 120 is connected to a first contact or electrode 125. The first electrode 125 is separated from a second electrode 130. Both electrodes 125, 130 are clamped on a wire or needle 135. For safety purposes, the electrodes 125, 130 are covered to avoid accidental contact between them. The second electrode 130 is connected to the return -12 vdc of the power supply PS1. The constant current I passes through a portion 140 of the needle 135 located between the separate electrodes 125, 130 apart. The current I remains constant despite the bioe load / needle resistance. This is because the voltage drop across the interrupting device 120 changes in response to the change in voltage drop across the needle portion 140. The change in voltage drop across the interrupting die 120 occurs because the total voltage between the two terminals (positive and negative terminals) of the power supply PS1 is 12 vdc constant, and the voltage drop across the reference resistor Rr «f ee constant, due to the constant voltage Viß in the node 18 A current sensing or measuring device 145 is connected to one of the electrodes 125, 130 to measure or detect the amplitude of the constant current I. Illustratively, the current sensing device 145 is a Hall effect transformer. interleaved around a line connecting the second electrode 130 to the return of -12 vdc of the power supply PS1. A visual indicator 150, such as a digital visual indicator, is connected to the current sensing device 145 to provide on-line continuous feedback alarms, which can be audible alarms in addition to visual indicators. The visual indicator may indicate the numerical value of the constant current I. Alternatively, or in addition, the digital visual indicator may have indications, such as three lamps, which indicate the amplitude of the constant current I as "high", "low" or "adequate". The "high" and "low" alarm signals can also be connected to a programmable logic controller 155 (PLC). The system PLC 155 can be programmed in any desired configuration to control automatic shutdown or provide alarm signals. For example, if the value of the sensed or measured current deviates from the desired constant current value by a predetermined amount, then the system PLC 155 can shut down the annealing process and stop a portion of the manufacturing line of manufacturing. needle. Alternatively, the system PLC 155 can be programmed to allow, for example, two consecutive incorrect d-current readings, and to stop annealing after three consecutive incorrect readings of annealing current amplitudes. The second adjustable device of the reference circuit 162 includes a time setting device 160 ßl which may be another thumb-operated wheel switch. The time setting device 160 and the current amplitude setting device 105 form the reference circuit 162 to program the desired annealing time and amplitude. The timing controlled thumb wheel 160 is connected to a time control PLC 165, which is connected to the PLC 155 of seven. The time control PLC 165 generates a digital time control signal after it has been driven by an annealing signal that comes from the system PLC 155. The annealing signal indicates that the electrodes 125, 130 are clamped on the wire or needle 135, which is ready to be annealed. The duration or pulse width of the digital time control signal is a function of the setting of the thumb-operated wheel of time control 160. The duration and amplitude of the constant current provides the proper annealing temperature, as was mentioned in relation to equation (1). Illustratively, the amplitude of the constant current varies from zero to 100 amps in 10 milli-amp increments, while the constant current duration or pulse width of the time regulation signal varies from 1 to 999. milli-seconds (msec), in increments of 1 msec. The output of the time control PLC 165 is connected to a solid state relay SSR1 to control the interruption thereof. Illustratively, the solid state relay SSR1 has a resolution of 1 msec. The solid-state relay SSR1 sends a time-regulating or pumping signal having a pumping width that is similar to the digital signal of digital time regulation, but more accurate. In addition, the time regulation signal provided by the solid state relay SSR1 has an amplitude that is different from the amplitude of the digital time control signal that comes from the time control PLC 165. Illustratively, the time regulation pulse has a baseline of zero volts and an amplitude of +15 volts. The solid-state relay SSR1 is connected to a work-time controller 170 which inputs the time-recording pulse to the switch 112 and the interruption device 120. When the time-regulating signal is high, the switch 112 it allows the reference voltage generated from the reference voltage generator 110, in response to the fixation of the thumb-driven wheel of amplitude 105, to reach the non-inverting input of the operation amplifier Al-1. At the same time, the operation amplifier Al-1 provides a constant voltage to terminal 18 of the reference resistor Rrtf. At the same time, the high-time regulation signal causes the constant current switch 120 to allow current to flow to the contacts 125, 130 to anneal the needle portion 140. In addition, the d constant current switch 120 maintains the annealing current at a constant amplitude. Since the voltage d of the other terminal 3 of the reference resistor Rr.f is? N +12 vdc constant, supplied by the power supply PS1, the voltage drop across the reference resistor Rrtf is constant. In addition, the voltage drop across the positive and negative terminals of the PS1 power supply; (connected to node 3 and contact 135, respectively), is a constant 12 vdc. The constant voltage falls through between the constant reference resistor Rr < f and through the terminals of the power supply PS1 to provide a constant annealing current I. The annealing current I remains constant regardless of the load variations, such as contact wear 125, 130, because the voltage drop across of the constant current switch 120 changes in response to changes in voltage drop across the needle 135, whereby the full voltage drop between the two terminals of the PS1 power supply remains at a constant 12 vdc. When the time control signal coming from the work time controller 160 is low, the switch 112 prevents the reference voltage q? E from the reference voltage generator 110 from reaching the operation amplifier Al-1. Instead, switch 112 provides +15 vdc to the operation amplifier Al-1, which maintains the voltage and node 18 to +15 vdc. This prevents the flow of current from the PS1 power supply, since the voltage (+15 vdc) at node 18 is greater than the voltage (+12 vdc) at node 3. At the same time, the regulation signal The low time that comes from the solid state relay SSRl causes the constant current switch 120 to derive or decrease any residual current out of the contact 125. This provides a fast response time, as well as the fast and clean transition between the states current on / annealing and current off / annealing. Figure 4 shows a detailed and illustrative schematic of an electrical circuit 200 that can be used to implement the block diagram resistor annealer 100 of Figure 3. The electrical circuit 200 provides a constant and precise annealing current for a precise duration, and comprises a thumb-operated current amplitude wheel switch 105 which is connected to an input of a reference voltage generator 110 of 0-10 v. For example, a setting of 00.00 on the amplitude wheel driven by the thumb 105 provides a reference voltage of 0 v, while a setting of 99.99 provides a reference voltage d v 10 v- The output of the generator «reference voltage 110 is connected to a non-inverting input of an Al-1 operation amplifier through a first resistive divider, two voltage followers or capacitor amplifiers Al-3 and Al-4 and a second resistive divider R8, R9. The first resistive divider includes a resistor R4 and a potentiometer R3. A second potentiometer R26 having one end connected to the bar d + 15 vdc has an armature connected to the first potentiometer R3. Potentiometer R26 provides +12 vdc to a terminal of potentiometer R3. In turn, the potentiometer R3 provides a reference voltage from 0 to 12 vdc. Several resistors are connected between the reference generator 110 and the operation amplifier Al-1 to provide the voltage division and the appropriate deviation. The voltages in the two inputs, that is, the inverter and noninverting inputs of the Al-1 operation amplifier are equal. The output 210 of the operation amplifier fll-1 varies to keep the two inputs Al-1 equal. In this way, in the annealing firing mode, the reference voltage coming from the potentiometer R3 is also present in the inverting input of the operation amplifier fll-1, whose inverting input is connected to the node 18 to provide a constant collector voltage Viß - The node 18 is a terminal of the reference resistor Rr * f, and a common collector dβ transistors npn 220, 225. The constant collector voltage Viß is equal to the reference voltage d £ e comes from the potentiometer R3 and is protected from immunity to the noise by the compensators Al-3, Al-4. In addition, the collector voltage Viß remains constant regardless of the voltage changes at output 210 of the operation amplifier fll-1. A diode D2, connected between the output 210 and the inverting input of the operation amplifier fll-1, prevents the output 210 from exceeding the inverting input by more than the voltage drop of the diode, e.g., 0.7 volts. A capacitor C5 and a resistor R14 are connected in series between the output 210 and the inverting input of the operation amplifier Al-1 to provide feedback and stability. The output 210 of the operation amplifier Al-1 is also connected to the base of a pnp transistor 012 through resistive deflection dividers R15-R16. The transistor 02 interrupts or turns on and off depending on the voltage value at the output 210. The collector of the transistor 02 is connected to the base Bl of a npn transistor 220 through a small deviation resistor R17, which may have a value of 10 ohms. The emitter of the transistor pnp 012 is connected to the common collectors of the npn transistors 220, 225. In the annealing mode of ignition, the transistor 012 is turned on and turns on the transistor 220, which turns on the transistor 225. The transistors 220 , 225 are collectively called 05 and together with the transistors 02, 03 and 04 (the transistors 03 and 04 are described below) form part of the constant current interrupting device 120, shown in Figures 3 and 4. Doe reference re-emitters of R12, R13, which are connected in parallel, are also connected to the output of the operation amplifier Al-1 210. Illustratively, the two parallel resistors R12, R13 each have a value of 0.1 ohms, to give as a result a reference resistance Rrtf q? e has an effective value of 0.05 ohms. The other terminals of the reference resistors R12, R13 are connected to a positive terminal 3 of a power supply PS1 of 125 amp and + 12 vdc. The power supply PS1 provides a constant current I to the needle 135 through the pair of electrodes 125, 130. The two electrodes 125, 130 are disposed and clamped on the needle 135 in the needle portion 140 which will be annealed. An electrode 125 is connected to an emitter El of the npn transistor 225. The other electrodes 130 are connected to the return side of the power supply PS1 of 12 vdc. A thumb-operated wheel timing control switch 160 is set by an operator to apply current I through the needle portion 140 for a desired duration. The thumb-operated wheel timing control switch 160 and the thumb-operated wheel current amplitude switch 105 form the reference circuit 162 to set the duration and amplitude of the annealing current I. thumb-operated wheel time regulation 160 is connected to a solid-state relay SSR1 through a time PLC 165. The solid state relay SSR1 is connected through a series of inverters and deflection resistors to the base of a pnp transistor 03. An output 270 of an inverter is connected to the resistors of deviation. The collector of the pnp transistor 03 is connected through a resistor to the base of an npn transistor 04. The emitter of the resistor 04 is connected to the power bar of -15 vdc, while the collector of the transistor 04 is connected to the base Bl of the npn 220 transistor. A second PS2 power supply, shown in FIG. 3, provides the +15 vdc high? n return of -15 vdc. The second power supply PS2 also has a common line of (direct current). A small resistor R28, e.g., of 22 ohms is connected between the collector of transistor 04 and the ground. In addition to being connected to the bias resistors of the pnp transistor 03, the output 270 of the inverter is also connected to the base of a pnp transistor 01 through a bias resistor R7. Another deflection resistor RB is connected between the base of transistor 01 and a +15 vdc bus. The emitter of transistor 01 is also connected to the +15 vdc bus through a DI diode. The collector of the pnp transistor 01 is connected to a non-inverting input of the voltage follower Al-4 through a resistor R9. Several capacitors derive the noise to the ground. Transistor 01 acts as a switch, similar to the introducer 112 shown in figure 3. In the annealing off mode, the transistor 01 is on to provide +15 vdc (from the +15 vdc bar, through the DI diode and the capacitor amplifier Al- 4) to the non-inverting input of the Al-1 operation amplifier. This pulls the voltage at the node 18 of the reference resistor Rrtf to +15 vdc to avoid the annealing current flow from the power supply PS1. The operation of the device 200 will now be explained. An operator sets the wheel current amplitude switch operated by the thumb 105 to a desired number between 0.00 to 99.00, corresponding to a constant annealing current of 0 to 100 amps released from the PS1 of 125 amp and +12 vdc. The output of the current amplitude by setting the thumb-operated wheel switch 105 causes the reference voltage generator 110 to provide a reference voltage, shown as Vrif / 2, to the non-inverting input of the Al capacitor. 3. As will be applied below, this reference voltage applies a constant control voltage Viß at node 18 during annealing or in the annealing state on. The operator also sets the thumb-operated wheel timing regulation switch 150 to provide a pulse of time regulation having a desired duration. Illustratively, thumb-operated actuation switches 105 ,. 160 are linear, where the change of the fixes changes linearly the amplitude and duration of the current respectively. The time control PLC 165 is driven or powered by the annealed signal d? E from the system PLC 155, indicating that the electrodes 125, 130 are clamped, and that the wire or needle 135 is ready for annealing. The time regulating PLC 165 will send a logical pulse having the desired pulse width or duration, as selected by setting the thumb-operated wheel timing control switch 160. The logic timing pulse is provided for turn on and off the SSRl solid state relay. The interruption of the solid-state relay SRR1 provides a pulse of time regulation having the same desired pulse width as the logic time control pulse, but with high precision and resolution, e.g., 0.1 msec resolution. However, the amplitude of the time regulation pulse ee of +15 volts, eg, when? N solid state relay SSR1 is off, and zero volts (i.e., connected to the ground) when the solid state relay SSR1 it's on The regulating time bleeder, shown as reference 280, is present at output 270 of inverter A2-5, after propagating through inverters A2-1, A2-3 and A2-5 forming the time controller 170 is shown in FIGS. 3 and 4. The time control pulse 280 is provided to the base of the transistors 01 and 03 through deflection resistors.

Annealing The needle or wire portion 140 is annealed by means of a constant current I flowing therethrough when the time control pulse 280 is high, e.g., +15 volts. The high-time regulation signal 280 allows the constant annealing current I to flow from the high terminal of + 12 vdc of PS1 to its return terminal -12 vdc through the reference resistor Rr * f, transistor 05 and portion of needle 140. This is achieved as follows. 01 ee off when the time control pulse 280 is high. This allows the reference voltage coming from the 0-10 volt reference generator 110 to pass through the Al-2, Al-4 and the operation amplifier fll-1, so a constant control voltage Viß appears at node 18. Node 18 is the terminal of the reference resistor Rrtf which is the opposite terminal 3 connected to the power supply PS1 of +12 vdc high. The transistor 02 is also on because the output 210 of the operation amplifier Al-1 is below the emitter voltage of iß. Transistor 02 on turns on transistor 05. Because transistor 05 is on, current I flows from the high side of power supply PS1 of 125 amp and +12 vdc, to electrode 125. Current I is constant because the control voltage Viß and the voltage of the PS1 power supply are constant. This will provide a constant voltage drop across the reference resistor Rrtf V a voltage drop of 12 vdc constant a. through the two terminals of the PS1 power supply. In this way, any voltage change through the needle 135 is compensated by the changes in the complementary voltage drop across the transistor 05 so that the voltage drops through the reference resistor Rrβf and through the two terminals of power supply P? 1 remain constant. That is, the traneer 05 compensates for any load variation. An illustrative example is shown below. When the thumb-operated wheel current amplitude switch 105 is set to provide a constant voltage at node 18 of 11.5 volts, (ie, Vi8 = 11.5 vdc), then the current through the reference resistor Rrtf of 0.05 ohm that has a voltage drop of 0.5 volts, is 10 amps (I = V / R = 0.5 volt / 0.05 ohms). This current I remains constant regardless of contact wear or variation in the resistance of the needle, since such variations are compensated by variations in the voltage drop through the traneistor 05. The transistor 05 and the operation amplifier Al-1 they ensure that the annealing current I remains constant despite variations in needle re-tension and contact. When constant voltages are falling through the constant resistor Rrtf and through the two terminals of the power supply PS1, together with the transistor 05, the constant current I is supplied. The constant current I flows through the first electrode 125 and the needle annealing portion 140. The constant current I comes out from the second electrode 130 and flows back to the return terminal -12 vdc of the PS1 power supply. The current I does not flow through the rest of the needle 135, since the power supply PS1 is isolated from the needle 135 or mass. In this state of turning on the current or annealing, the +15 volts of the time adjustment screw 280 turn off the transistors 03 and 04.

Annealing off The annealing current constant is withdrawn after the desired annealing time, corresponding to the width of the time control signal 280. The traneistor 01 is turned on when the time control pulse 280 is zero volts. . The on transistor 01 provides +15 vdc, through the diode DI, to the node 285 located between the resistors R8 and R9 that connect the output of the capacitor Al-3 to the input of the capacitor Al-4. The +15 voltage at node 285 produces approximately +15 vdc at node 18. Because the +15 vdc voltage at node 18 is higher than the voltage at the other terminal of the Rrtf reference resistor, ie, in node 3 which is connected to power supply PS1 of +12 vdc, no current flows from the power supply PS1 of +12 vdc to the reference resistor Rrtf - When transistor 01 is on, transistor 02 it is off because the output 210 of the operation amplifier fll-1, (which is connected to the base of the transistor 02 through the resistive dividers R15, R16) is greater than +12 vdc, which is greater than the emitter voltage of transistor 02 at node 18. Transient off 02 turns off transistor 05. This transistor 05 off electrically disconnects the first electrode 125 from the reference transistor Rrtf, also avoiding any current flow from the PS1 power amplifier of +12 vdc to the first electrode 125. In the annealing off mode, the voltage levels in the emitters of the transistors 220, 225 are zero volts. In addition, to provide a fast and defined transition between the on and off states of the current, the transistors 03 and 04 are turned on to derive or decrease the residual current q? E from the transistor 05. The on transistor 04 provides -3 vdc to the base of transistor 220. The -3 vdc is produced by connecting a Zener D3 diode between the -15 vdc bar and the emitter of transistor 04. The -3 vdc in the base dβ transistor 220 and the zero volt level in The transmitter of the transient 220 provides fast and sharp off of the transistors 220, 225. The zero volt level of the time control signal 280 turns on the transistors 03, 04. This decrease in current by means of the transistors 03, 04 removes peaks of lightning strike or bipole during transitions between on and off states. This allows the constant current resistive d annealed device 200 to have a fast interruption response. The transistor 04 is a shunt switch q? E is turned on by the transistor 03, when the transistor 03 is turned on when the time regulating signal 280 is zero volts. The resistors R17, R28 q? E are connected to the collectors of the transistor 02, 04, respectively, have a low value to provide fast and sharp transitions between the on and off state of the current. This allows the annealing device to have a fast response time and provides the constant annealing current I for a precise and accurate predetermined time. In the present invention, a method for annealing a wire portion using a constant current annealing device comprises the steps of: (a) setting an amplitude and? N constant current time by means of reference circuit 162; (b) supplying the constant current I to the needle 135a through the interrupting device 120; and (c) varying a resistance of interrupt die factor 120 in response to resistance changes in needle 135. In the other mode, step i c) is replaced by that of interrupting interrupt device 120 to decrease a residual current while that switch 112 is interrupted to stop the generation of current I. The step of providing a constant current comprises the steps of: connecting a terminal 3 of the reference resistor Rrtf to the power supply PS1; generating a reference voltage using the reference voltage generator 110; and interrupting switch 112 to provide the reference voltage at another terminal 18 of the reference resistor Rrtf using the operation amplifier Al-1. Another step includes generating a current time regulation signal using the programmable timing controller logic 165. Other steps include: mounting a plurality of surgical needles on a carrier strip 15 (Fig. 1); moving the mounted needles through the annealing device; setting a current amplitude using the current amplitude setting device 105; setting the current time using the device for setting current duration 160; holding a pair of separated electrodes 125, 130 on the wire or needle 135; generating an annealing signal from a programmable logic controller of system 155 indicating the completion of the fastener; measuring an amplitude of the constant current I using a current detector 145; indicating a level of the current amplitude detected in a monitoring device 150; and stopping the annealing device when the indicated current level exceeds a predetermined level or when a number of inappropriate indications exceeds a predetermined number; The constant current annealing device can be used in line or offline to accurately anneal needle or wire portions at high speed. For example, speeds of 120 to 240 parts per minute are achieved. A constant current that has a precise amplitude and duration quickly heats and anneals the wire portion. The current can have a high amplitude, up to 100 amps for example. The longer currents can be released by reconfiguring the wheel amplitude switch operated by the thumb 105 and the potentiometer R3. An energy supply that has more than 125 amps capacity can also be used in place of the PS1 power supply for larger annealing current capacities. Diepoeitive dß annealing current allows the precise annealing and high speed of small wires as well as large wires that require large currents for an adequate annealing. The needles can be transported using a stepping motor indication, where each needle is moved and stopped in position for annealing, and moved again after its annealing. The electrodes can be metal, ceramic or a combination of the same. The electrodes can be held in the needle through an air-driven cylinder or a motor-driven mechanical clamping device. This quickly reduces and dampens the vibrations that result from holding the electrode to further increase the speed of needle output. The constant current annealing device provides high repeatability and has a rapid interruption reeppette. An identical and accurate current (in amplitude and duration) is applied to each needle, regardless of contact wear, contamination of the needle surface or fluctuations in the AC power line. In addition, the constant current annealing device provides an automatic annealing in which continuous on-line feedback and the ßmisionee of alarm automatically indicate an inadequate annealing. The constant current annealing die automatically turns off when a predetermined unsuitable annealing occurs. The current annealing device is safe, since the contacts or electrodes are covered and there are no open flames. The absence of flames also prevents the accumulation of soot / carbon on the annealed surface. Although the invention has been particularly shown and described with respect to the illustrative and embodied embodiments thereof, it will be understood by those skilled in the art that the foregoing and other changes in form and detail may be made thereto without departing from the spirit and the scope of the invention, which must be united only by the scope of the appended claims.

Claims (26)

1. NOVELTY OF THE INVENTION CLAIMS 1. - A constant current annealing device for annealing a surgical needle, said device comprises: at least one reference circuit for setting a time > and desired annealing current; a pair of electrodes separated apart and fastened on said needle; a constant current source connected to said reference circuit; and an interrupting device connected between said constant current source and said pair of electrodes, said interrupting device interrupts in response to a time regulation signal coming from said reference circuit; said constant current source provides a constant current through said pair of electrodes to anneal said needle, a voltage drop across said interruption die varies in response to changes in a voltage drop across said needle, so That said current remains constant.
2. 2. The constant current annealing device according to claim 1, wherein said constant current source comprises: a constant voltage generator that generates a constant voltage in response to said fixed current; an energy supply that supplies said constant current; and a reference resistor having a first terminal connected to said power supply, and a second terminal connected to receive said constant voltage.
3. 3. The constant current annealing device according to claim 1, wherein said constant current source is interruptable through a switch between the on and off state in response to said annealing time.
4. 4. The constant current annealing device according to claim 1, wherein said reference circuit comprises: a current amplitude setting device that generates a current amplitude signal; and a time-setting device that generates a d-time regulation signal.
5. 5. The constant current annealing device according to claim 4, wherein said current amplitude setting device includes a wheel amplitude switch operated by the thumb and said time setting device includes a switch of regulation of wheel time triggered by the thumb.
6. 6. The constant current annealing device according to claim 1, wherein said reference circuit includes a programmable logic controller for time regulation and a solid state relay connected to said programmable logic controller for time regulation, said programmable logic controller of time controlling said winding relay to generate a time regulation signal.
7. 7. The constant current annealing device according to claim 6, further comprising a seven-programmable logic controller that drives said programmable logic regulator to generate said time signal when said pair of electrodes is clamped. on said needle.
8. 8. The constant current annealing device according to claim 1, further comprising a current measuring device connected to one of said pair of electrodes for measuring an amplitude of said constant current. 9.- The annealing device of the connecting current according to claim 8, wherein said current measuring device is a Hall effect transformer placed around a line connected to one of said electrodes, said connecting current passing through dß said line. 10. The constant current annealing device according to claim 8, further comprising a visual indicator connected to said measuring device d.sub.current, said visual indicator shows an indication of said amplitude of said constant current. II.- The constant current annealing device according to claim 8, which further consists of a programmable logic system controller that turns off said constant current source after said amplitude is deflected by a predetermined amount. 12. A constant current annealing device for annealing a surgical needle, said device comprises: at least one reference circuit for setting a desired annealing time and current; a pair of electrodes separated apart and fastened on said needle; a constant current source connected to said reference circuit, said constant current source provides a constant current for annealing said needle; and an interrupting device connected between said source of constant current and said pair of electrodes, said interrupting device interrupts in response to a time regulation signal coming from said reference circuit; said constant current source provides a constant current through said pair of electrodes when said interrupting device is in position, and said interrupting device derives a residual current out of said pair of electrodes when said interrupting device is in another position. 13. A constant current annealing device for annealing a surgical needle, said device comprising: at least one reference circuit for setting a desired annealing time and current d; A pair of electrodes separated apart and fastened on said needle; A constant current source connected to said reference circuit, said constant current source provides a constant current for annealing said needle; and an interrupting device connected between said constant current source and said pair of electrodes, said interrupting device interrupts in response to a time regulation signal coming from said reference circuit; said constant current source provides a constant current through said pair of electrodes when said interrupting device is in a poem, and said interrupting device derives a residual current out of said pair of electrodes when said interrupting device is in another position , varying a voltage drop across said interrupting device in response to changes in a voltage drop across said needle so that said current remains constant. 14. A method for annealing a surgical needle using a constant current annealing device comprising the steps of: (a) setting a constant current amplitude and? N current time; (b) providing a constant current for said set time for said needle through an interrupting device; and (c> varying a voltage drop across said interrupting device in response to a change in voltage drop across said needle 15. The method according to claim 14, wherein said The fixing step comprises the steps of: setting said current amplitude using a current amplitude setting device, setting said current time using a current duration setting device, 16. The method according to claim 14, wherein said provisioning step comprises the steps of: generating said constant current by providing a constant voltage drop across a reference resistor, and generating a current time regulation signal to interrupt a switch and a switching device; 17. The method according to claim 14, further comprising, before step (a), the steps of: securing a pair of elements; separate electrodes on said needle; and generating an annealing signal from a programmable logic controller of the system indicating the completion of said clamping. 18. The method according to claim 14, wherein said step of provision comprises the steps of: connecting said terminal of said reference resistor to a power supply; generate a reference voltage using a reference voltage generator; and interrupting a switch to provide said reference voltage at another terminal d said said reference resistor using an operation amplifier. 19. - The method according to claim 14, wherein said provisioning step generates a time signal using a programmable logic controller of time regulation. 20.- The method according to the claim 14, which further comprises the steps of: measuring an amplitude of said constant current using a current detector; and indicate a level of said amplitude of the detected current in a monitoring device. 21. The method of compliance with the claim 20, further comprising stopping said annealing die when said indicated current level exceeds a predetermined level. 22. The method according to claim 20, further comprising stopping said annealing device when a number of inappropriate indications exceeds a predetermined number. 23. A method for annealing a surgical needle using a constant current annealing device which comprises the steps of: (a) setting an amplitude and a constant current time; (b) providing a constant current to said needle through an interrupting device; and (c) interrupting said interrupting device to decrease a residual current while a switch is interrupted to stop the generation of said current. 24. A method for annealing a surgical needle using a constant current annealing device comprising the pads of: (a) setting an amplitude and a constant current time; (b) supplying said constant current to said needle through an interrupting device; Ce) varying a voltage drop across said interrupting device in response to changes in the voltage drop across said needle; and (d) interrupting said interrupting device to decrease a residual current while a switch is interrupted to stop the generation of said current. 25. A method for annealing a surgical needle comprising the steps of: (a) setting an amplitude and a constant current time; (b) providing a current having said constant amplitude set to heat and anneal said needle during said fixed constant time; and (c) varying a drop in response to changes in a voltage drop across said needle so that said amplitude of said current in said needle remains constant, 26. The method according to claim 25, further comprising the steps of: mounting a plurality of surgical needles on a carrier strip, moving the mounted needles through an annealing means, and decreasing a residual current while stopping the generation of said current. SUMMARY OF THE INVENTION A counting current annealing device for annealing a wire or surgical needle is described; the diepoeitive includes amplitude and time setting devices, such as thumb-operated wheel switches; a constant current source is connected to the current setting device; the constant current source is interchangeable, through a switch, for example, in response to a time control signal to provide a constant current for a predetermined duration; a pair of separate separate electrodes are clamped on the needle and an interrupting device is connected between the constant current source and the pair of electrodes; the voltage drop across the interrupting device varies to compensate for load variations, thus keeping the annealing current constant in the annealing firing mode; in the annealing off mode, when no current is supplied to the needle, the interrupting device derives a residual current away from the electrodes; The time-setting device includes a programmable logic controller (PLC) and a solid-state relay to provide an accurate timing control signal; A current measuring and monitoring device is connected to another PLC, which turns off the annealing device after a predetermined number of alarms or after the constant current amplitude is deflected by a predetermined amount. 3N / ycl * l? M * lss * avc P97-502