How to connect a signal between classes in PyQt5

Question

I have very common question but it is not easy for me.

I'm trying to connect a PyQt signal from the MainWindow class to the CheckExcel class, but It doesn't work. I think some of people know how to do this, but some of them do not. Most people who doesn't know pointed out the code... but please don't do it. My point is how could I connect this?

Here is some code below:

class CheckExcel(QtCore.QThread):
    updated = QtCore.pyqtSignal(int)
    updateLab = QtCore.pyqtSignal(str)
    running = False

    def __init__(self, parent=None):
        super(CheckExcel, self).__init__(parent)
        self.progPercent = 0
        self.running = True

    def run(self):
        pythoncom.CoInitialize()

        try:
            while self.running == True:

                self.updated.emit(int(self.progPercent))
                self.updateLab.emit(str(va_TC))

                print(self.progPercent)

        except :
            print('Excel is not executed')

            CheckExcel().run()

class MainWindow(QtWidgets.QMainWindow):
    def __init__(self, parent=None):
        super(MainWindow, self).__init__(parent=parent)
        self.setupUi(self)

    def startBtnClicked(self):

        self.chk_excel = CheckExcel(self)
        self.chk_excel.start()

        self.chk_excel.updated.connect(self.updateValue)
        self.chk_excel.updateLab.connect(self.updateLabel)

    def updateValue(self, data):
        self.progressBar.setValue(data)

    def updateLabel(self, text):
        self.label.setText(text)

    def stop(self):
        self.event.set()

if __name__ == "__main__":
    app = QtWidgets.QApplication(sys.argv)
    w = MainWindow()
    w.show()
    sys.exit(app.exec_())