Structure of oil filling device

An oil filling device, comprising:

• an oil filling funnel, which has a lower end to which an insertion connector is connected, the insertion connector having a lower end to which an angled fitting is mounted in such a way that a funnel hole of the oil filling funnel, a connector hole of the insertion connector, and an angled fitting hole of the angled fitting are in communication with each other;
• an extendable tube assembly, which comprises a first tubular member having a first end to which an end of the angled fitting is fit so that the angled fitting hole is in communication with a first bore defined through the first tubular member, the first tubular member having an opposite end to which an end connector is mounted, the end connector forming therein a tapered bore that comprises at least a tapering section that receives and retains therein a conical wedge block that has a C-shaped cross-section, a second tubular member being telescopically received through the conical wedge block and into the first tubular member, a fastening element having an internally threaded hole that is set in engagement with an external thread of the end connector, whereby with the second tubular member being telescopically moved with respect to the first tubular member to assume a desired length, the fastening element is rotated to drive the conical wedge block further into the tapered bore to get compressed and simultaneously fix the first tubular member and the second tubular member to each other, the first bore being in communication with a second bore defined through the second tubular member;
• a direction adjustment assembly, comprising a rotary adjustment knob, a fastening knob, and a T-shaped fitting, the T-shaped fitting having a top portion forming a lateral passage to receive the rotary adjustment knob to extend therethrough in such a way that the rotary adjustment knob is rotatable with respect to the T-shaped fitting, the T-shaped fitting comprising a vertical passage formed therein to extend downward from and in communication with the lateral passage, the rotary adjustment knob having a first end forming an internally threaded hole that engages an external thread formed at a free end of the second tubular member and an opposite second end forming a hole in communication with the internally threaded hole, the rotary adjustment knob having a circumferential wall in which a plurality of through holes is formed to correspond to the vertical passage to communicate with the vertical passage, the rotary adjustment knob comprising an external thread formed at the second end thereof to engage an internal thread formed in the fastening knob, whereby when the rotary adjustment knob is rotated and set at a desired angular position, the fastening knob is rotated to abut against the T-shaped fitting and thus secure the rotary adjustment knob in position;
• and
• a coupling assembly, which comprises a locking cap, the locking cap forming an insertion bore to receive and retain the T-shaped fitting in such a way that the vertical passage is in communication with the insertion bore, the locking cap having a lower end forming an external thread adapted to engage an internal thread of an oil filling opening of an engine in such a way that the insertion bore is in communication with the engine, the external thread of the lower end of the locking cap being selectively provided with a gasket set around an outer circumference thereof.