Abstract: Mainly introduced uses in high speed flush joint’s machine two which the microcomputer controls composing hardware’s triturating and the principle of work importantly. The foot board controller is uses for to control the electrical machinery rotational speed as well as to give the sewing machine starting and cuts the line signal, the nose synchronization locator is uses for to produce the high and low needle position signal and the nose induces the signal, mainly uses in sewing machine’s pinpointing and the electrical machinery rotational speed test.
Key word: High speed flush joint machine; Foot board; Nose synchromesh; Hall sensor
Introduction
By the needlework, the shuttle line two sewing threads, form through machine’s movement lock the type line mark, sutures two or the multi-layered seam material in the same place industry sewing machine is called the flush joint machine. It is most widespread in the tailoring industry use, the variety are also many, sews one of equipment manufacture profession leading products, also tailors one of profession amount of use biggest equipment, divides into the low speed, the medium speed and the high speed flush joint machine according to the speed.
But, the domestic sewing machine factory basically is at present produces the machine part, but purchases overseas or Taiwan and so on some company’s controller, then assembles the sell again. This greatly increased the cost, reduced the profit. This article according to the market demand, has designed one kind not brushes the control system which by the 196MC monolithic integrated circuit and the cocurrent the electrical machinery is composed to control the high speed flush joint machine. In sewing machine’s triturating, besides main control box, but also two important hardware system, one treadons the controller, other one is the sewing machine nose synchronization locator.
1 foot board controller
The high speed flush joint which machine controls by the microcomputer requests the electrical machinery in the 150~4500r/min scope adjustable, and can realize stops the needle position, to dial the line, to cut the line function automatically. Certainly, the sewing machine makes these movements is must complete under operators’ concrete operations, foot board controller in sewing machine system is this kind of function: As electrical machinery’s start signal, the speed demand signal as well as cuts the line signal the occurrence controller, below concrete study its principle of work.
The speed demand signal produces the basic principle is examines the magnetic field using the linear Hall component the change, reflects on the foot board connecting rod’s magnet movement condition, through transports again puts carries on to this signal processes to certain scope in (0~5V), provides for control panel’s on monolithic integrated circuit, carries on A/D to transform, thus realizes with the foot board control speed size.
The Hall electromotive force is
UH=KHICB= (RH/d) ICB (1)
In the formula: KH is the Hall part sensitivity;
IC is the controlling current;
B is the magnetic induction intensity;
RH is the Hall coefficient, decided by the material, N semiconductor RH=1/(nq), n is the carrier concentration, q is the electronic charge quantity;
d is Hall part thickness.
By the type (1) may see that regarding the definite Hall component, UH decides in controlling current IC and magnetic induction intensity B. If maintains IC is invariable, then UH may in certain magnetic induction intensity scope along with the B linear variation, therefore, the key question is causes UH∝B. In assigns the magnet and under the external dimensions, this article selects take InSb as material linear Hall sensor HW300B. Its basic material may see also HW300B DataSheet, here only gives its most basic UH and the B linear diagram of curves, as shown in Figure 1. Figure 1 Vc is the voltage which the control end adds, Ic is the controlling current.
The foot board controller besides gives the speed demand signal, but must give starting and cuts the line signal, its basic principle is the use and the foot board connecting rod connected two back plates in the suitable position mask electro-optic to tube’s emitting light, thus obtains the reflection connecting rod position two switching signal.
Figure 2 is starting and cuts the schematic diagram which the line signal produces, has 4 pin components is the electro-optic to the tube, his/her foot 2 and the foot 4 are the light emitter diode, the foot 1 and the foot 3 for the output triode. When has not been covered to the tube, the output triode breakover, the foot 3 are the low level, the external connection triode up to, switching signal for high; When is covered to the tube, the output triode up to, the foot 3 is the high level, the external connection triode breakover, the switching signal for low. Thus, may realize the function which requests.
In concrete application process, but also some various signals coordination use question, i.e., when foot pedal connecting rod position variation, the above 3 signals appear succession question, to explain that this question, we define an explanation question the first method, namely connecting rod’s movement we use the angle to measure, this angle defines as the movement when connecting rod spool thread and between the connecting rod static time spool thread’s included angle, is called forward to the starting direction movement, to cuts the line direction movement to be called reverse.
The sewing machine regarding these 3 signal’s request is, when the starting signal arrives, request rate signal Vs cannot surpass 0V, otherwise, will carry on a/D transformation later to surpass the most slow-speed of revolution which the sewing machine will establish, should choose is being lower than 0V is suitable; The starting later speed makes the linear variation along with the connecting rod angle’s change, when close angle maximum value achieves transports puts the most greatly saturated output; When in the connecting rod counter motion process, has first cuts the line signal, then has the starting signal again; After adjusts the later various signals test diagram of curves as shown in Figure 3. The abscissa is the link motion angle, the unit is. Carries on the suitable adjustment to the circuit value, may obtain time the normal work curve.
2 nose synchronization locator and velocity generator
The microcomputer controls a sewing machine’s important target is the engine off position accuracy, here including on needle position and under needle position engine off, therefore, the sewing machine must give a signal respectively in these two positions, the monolithic integrated circuit only then may through examine these two signals to control the electrical machinery to stop. Also, if must examine sewing machine’s rotational speed, may examine through nose’s velocity generator, like this, in fact the nose simultaneously has the above two kind of functions.
The high and low needle position signal’s production is mainly the dependence installs on nose’s two polar opposite magnet (with electrical machinery revolving), (fixed) affects to two opposite installment’s switch Hall sensors, namely each magnet only corresponds a sensor to have an effect. When the nose revolves to needle position or under the needle position position, because the corresponding switch Hall sensor the magnetic field arrives at its jump the threshold value, but has the output jump, is also the need switching signal. The speed detection signal produces the basic principle is the nose intension including a ring-like hollow iron hoop, its inner rim is a uniform distribution, mutually the linking 24 pair of sockets, in the hollow link circles has the coil, then the entire installment is equal to a 24 antipode asynchronous machine, can have the frequency for the rotational speed 24 time of output induced emfs.
The switch Hall sensor application is simple, only defers to the typical connection then. What here selects is Allegro Corporation’s U3144. The peripheral circuit only need connect an input resistance to pull the resistance with an output. Figure 4 is the switch Hall sensor’s model application connection, Figure 5 is this component model movement and the release magnetic induction intensity diagram of curves.
From Figure 5 may see that this component has a sluggishness in the Vo~B curve, provides one to have certain pulse width signal. The top and bottom needle position signal correspondence’s sensor must install on the contrary mutually, because the corresponding magnet is also the opposite installment, then each sensor revolves for one week in the nose only to act one time.
3 experimental results and summary
This article introduced two hardware already applied in the high speed flush joint which machine controls in the microcomputer, moreover the performance is good, the work is stable, can meet requirements in advance. Figure 6 is the foot board controller’s output starting signal and the speed control demand signal. Figure 7 is the high and low needle position signal.
