Patent EP-2333397-A1 (EP)
Inventor: GOMES DE FIGUEIREDO CARLOS JOAO
IPC: F16N11/08
Filed: 2009-12-11
Abstract: The automatic lubricator provides periodic injections of a lubricant fluid, according to a pre-programmed functioning period. The injection process is accomplished by the movement of a piston enclosed in a reservoir, where the volume between the piston and the end wall of the reservoir is filled with the lubricant fluid. The piston movement is assured by a telescopical spindle, which receives a rotational motion provided by a gearbox, and converts it into a linear movement to compel the piston forward, and consequently expelling the lubricant fluid from the reservoir through the sprue channel, that exits at the end of the reservoir. 
     The telescopical spindle is made of several hollow, both internal and external, threaded cylinders, except for the first, which is solid with external screw thread and the last which is only threaded on the inside. The last cylinder is assembled with the piston that is equipped with an anti-rotating system, through the action of two guide leaders. Initially, all the cylinders are withdrawn and the piston is in the upper position. The rotational motion is transmitted by the gearbox to the first cylinder of the telescopical spindle. When the first cylinder initiates its movement, since the remaining cylinders are on their initial position and the last is connected to the piston , the first cylinder begins to unscrew from the inside of the second, until it reaches a travel limiter characterized by a thread discontinuity. At this point, the first and second cylinders become solidarily bounded, meaning that they will rotate together as one and begin to unscrew from the inside of the third. This type of functioning repeats itself throughout all the screwed together cylinders until the piston reaches the end of its stroke. During the unscrewing process of the various cylinders, the piston moves proportionally to the cylinders' thread pitch, at the rotation speed provided by the electrical motor, divided by the gearbox ratio. 
     The gearbox is powered by an electrical motor, which functions periodically, controlled by a microcontroller. The microcontroller allows the engine to rotate in the opposite direction in order to withdraw the piston, avoiding high pressures in the lubrication circuit. 
     The injection period adjustment is accomplished by a scaled turning selector, which transmits the information regarding the selected working period to the microcontroller. In the selectors OFF position, the automatic lubricator master switch is turned off, allowing the whole system to stop for an undetermined time period, without power consumption. 
     An optical reading sensor is used to assess the amount of lubricant fluid dispensed by the system, which measures the last gears rotational movement, being this proportional to the pistons linear movement, allowing the calculation of the amount of expelled lubricant fluid. One of the necessary variables to measure the lubricant fluid injection pressure is the electrical current consumed by the motor. This measurement is performed by a digital/analogical converter that exits in the microcontroller. With this data, and knowing the internal geometry of the automatic lubricator is possible to calculate the exiting pressure of the lubricant fluid. 
     The number of lubricant fluid injections, as well as the elapsed time period from the last shot is stored in a non volatile memory, which is part of the microcontroller. The systems reset consists in deleting the above mentioned stored values from the microcontrollers internal memory. 
     The automatic lubricator is equipped with signaling LEDs, that contemplate possible functional flaws such as; batteries tension lower than 2.4 Volt, lubricant fluid depleted and injection pressure over 10 Bar.