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(11) | EP 3 095 752 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
| published in accordance with Art. 153(4) EPC |
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| (54) | OIL RETURNING STRUCTURE |
| (57) An oil return mechanism includes a base, a control switch, a first blocking ball
mounted in the base, an elastic member mounted between the first blocking ball and
the base. The base has a liquid storing cavity, a liquid returning cavity, a communicating
cavity, a first communicating opening communicating between the liquid returning cavity
and the communicating cavity, and a second communicating opening communicating between
the communicating cavity and the liquid storing cavity. The control switch is adapted
for controlling the second communicating opening open or closed so that the communicating
cavity and the liquid storing cavity are connected or separated. The first blocking
ball moves between a blocking position and an open position. The first communicating
opening is positioned in a communicating portion of the base. When the first blocking
ball is in the blocking position, one or more liquid guiding gaps are formed between
the first blocking ball and an inner wall of the communicating portion of the base.
The liquid guiding gap communicates between the liquid returning cavity and the communicating
cavity. The present invention can regulate a speed of a fluid flowing from the liquid
returning cavity to the communicating cavity, and has the advantages of simple structure
and great reduction of cost. |
TECHNICAL FIELD
BACKGROUND
[0002] A jack is generally configured with an oil return mechanism. A conventional oil return mechanism includes a liquid storing cavity, a liquid returning cavity, and a communicating cavity communicating between the liquid storing cavity and the liquid returning cavity. The communicating cavity is configured with a control switch for selectively conducting the on-off control of the communicating cavity. A speed of a fluid flowing from the liquid returning cavity to the communicating cavity has a direct impact on a descending speed of the jack in operation. However, when the control switch is on, the speed of the fluid flowing from the liquid returning cavity to the communicating cavity remains stable, and thus the jack descends rapidly either in a no load condition or in a load condition, which may result in accidents, for instance, a lifting load rapidly falling down from the operating jack to hurt an operator. Therefore, the conventional oil return mechanism is configured with a speed regulating device for regulating the speed of the fluid flowing from the liquid returning cavity to the communicating cavity in accordance with the different operation condition of the jack. However, the expensive speed regulating device adds significant cost to the oil return mechanism, and thus the oil return mechanism fails to satisfy industrial requires.
SUMMARY OF THE INVENTION
[0003] To overcome the defects described above, the present invention provides an oil return mechanism which can regulate a speed of a fluid flowing from a liquid returning cavity to the communicating cavity, and reduce costs efficiently.
[0005] An oil return mechanism, comprising:
a base, a control switch, a first blocking ball mounted in the base, an elastic member mounted between the first blocking ball and the base; wherein the base has a liquid storing cavity, a liquid returning cavity, a communicating cavity, a first communicating opening communicating between the liquid returning cavity and the communicating cavity, and a second communicating opening communicating between the communicating cavity and the liquid storing cavity; the control switch is adapted for controlling the second communicating opening open or closed so that the communicating cavity and the liquid storing cavity are connected or separated; the first blocking ball moves between a blocking position and an open position with an external force; when the first blocking ball is in the open position, the whole first communicating opening is open, and thus a fluid flows from the liquid returning cavity to the communicating cavity; the first communicating opening is positioned in a communicating portion of the base; when the first blocking ball is in the blocking position, one or more liquid guiding gaps are formed between the first blocking ball and the communicating portion of the base; and the liquid guiding gap communicates between the liquid returning cavity and the communicating cavity.
[0006] The control switch includes a second blocking ball mounted in the base and a valve rod; the valve rod is adapted for pushing the second blocking ball in a sealing position for sealing the second communicating opening; and the valve rod is threadly coupled to the base.
[0007] An end of the elastic member is mounted in the communicating cavity, and the other end of the elastic member is positioned against the first blocking ball.
[0008] The first blocking ball moves between the blocking position and the open position under the cooperative control of an elastic force of the elastic member and a hydraulic pressure of the liquid in the liquid returning cavity.
[0009] The open position is positioned in an end of the liquid returning cavity adjacent to the first communicating opening, and a diameter of the end of the liquid returning cavity is larger than the one of the first blocking ball.
[0010] The elastic force generated by the elastic member acts on the first blocking ball from the blocking position to the open position.
[0012] A plurality of liquid guiding gaps is formed between the first blocking ball and the communicating portion of the base.
[0013] Beneficial effects of the present invention are as follows:
In use, when the first blocking ball moves to the open position or the blocking position, the fluid can flow to the communicating cavity through the second communicating cavity or the liquid guiding gap, to reduce the amount of the flowing liquid, and thus regulate the speed of the fluid flowing from the liquid returning cavity to the communicating cavity. Moreover, the present invention has the advantages of simple structure, convenient manufacture and great reduction of cost. The liquid guiding gap formed between the first blocking ball and an inner wall of the communicating portion has an advantage of avoiding clogging.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014]
FIG. 1 is a construction schematic diagram of the present invention;
FIG. 2 shows a first blocking ball positioned in an open position.
FIG. 3 shows the second blocking ball positioned in a blocking position.
FIG. 4 is a construction schematic diagram of another embodiment of the present invention.
Reference numbers in the drawings are as follow:
[0015]
1, base; 11, liquid storing cavity; 12, liquid returning cavity; 13, communicating cavity; 14, first communicating opening; 15, liquid guiding gap; 2, first blocking ball; 3, elastic member; 4, second blocking ball; and 5, valve rod.
DETAILED DESCRIPTION OF THE PREFERED EMBODIMENTS
[0016] Referring to the FIG. 1 to FIG. 3, an oil return mechanism includes a base 1, a control switch; a first blocking ball 2 mounted in the base 1, an elastic member 3 mounted between the first blocking ball 2 and the base 1. The base 1 has a liquid storing cavity 11, a liquid returning cavity 12, a communicating cavity 13, a first communicating opening 14 communicating between the liquid returning cavity 12 and the communicating cavity 13, and a second communicating opening communicating between the communicating cavity 13 and the liquid storing cavity 11. The control switch is adapted for controlling the second communicating opening open or closed so that the communicating cavity 13 and the liquid storing cavity 11 are connected or separated. The first blocking ball 2 moves between a blocking position and an open position with an external force. When the first blocking ball 2 is in the open position, the whole first communicating opening 14 is open, and thus a fluid flows from the liquid returning cavity 12 to the communicating cavity 13. The first communicating opening 14 is positioned in a communicating portion of the base 1. When the first blocking ball 2 is in the blocking position, one or more liquid guiding gaps 15 are formed between the first blocking ball 2 and the communicating portion of the base 1. The liquid guiding gap 15 communicates between the liquid returning cavity 12 and the communicating cavity 13.
[0017] In use, when the first blocking ball 2 is in an open position, a fluid flows from the liquid returning cavity 12 to the communicating cavity 13 through the first communicating opening 14. When the first blocking ball 2 is in the blocking position, the fluid flows from the liquid returning cavity 12 to the communicating cavity 13 through the liquid guiding gap 15, which can reduce the amount of the flowing liquid. Therefore, the speed of the fluid flowing from the liquid returning cavity 12 to the communicating cavity 13 can be regulated by the movement of the first blocking ball 2. When the jack is in operation and no-load, the first blocking ball 2 is in the open position, and the liquid flows from the liquid returning cavity 12 to the communicating cavity 13 through the first communicating opening 14, so that the jack slows down rapidly. When the jack is on load, the first blocking ball 2 is in the blocking position; the fluid can only flows to the communicating cavity 13 through the liquid guiding gap 15. The liquid guiding gap 15 can reduce the amount of the flowing liquid, thus the fluid slows down, and the jack descends slowly. The present invention has the advantages of simple structure, convenient manufacture and great reduction of cost. The liquid guiding gap 15 has an advantage of avoiding clogging.
[0018] The liquid guiding gap 15 can be manufactured as follows. A sealing surface in the communicating portion is made firstly, and the sealing surface matches the first blocking ball 2. Secondly, a recess in the sealing surface is made so that the first communicating opening 14 is not completely sealed when the first blocking ball is in the blocking position. In other embodiments, the first blocking ball 2 may be irregular shape so that the first communicating opening 14 is not completely sealed. The size of the liquid guiding gap 15 has a direct impact on the speed of the returning fluid in the blocking position, and can be set as requirements. The amount of the liquid guiding gap 15 can be set as requirements, such as one or more.
[0019] Specifically, an end of the elastic member 3 is mounted in the communicating cavity 3, and the other end of the elastic member 3 is positioned against the first blocking ball 2, which is convenient for assembling.
[0020] The first blocking ball 2 moves between the blocking position and the open position with the external force, such as hydraulic pressure. Preferably, the first blocking ball 2 moves between the blocking position and the open position under the cooperative control of an elastic force of the elastic member 3 and the hydraulic pressure of the liquid in the liquid returning cavity 12. Specifically, the open position is positioned in an end of the liquid returning cavity 12 adjacent to the first communicating opening 14, and a diameter of the end of the liquid returning cavity 12 is larger than the one of the first blocking ball 2.
[0021] The elastic force generated by the elastic member acts on the first blocking ball 2 from the blocking position to the open position. That is to say, the elastic member 3 is in a compressed state when the first blocking ball 2 is in the blocking position. The elastic member 3 generates a force on the first blocking ball 2 towards the open position when the elastic member 3 is released. The liquid in the liquid returning cavity 12 generates a force on the first blocking ball 2 from the open position to the blocking position.
[0023] The control switch includes a second blocking ball 4 mounted in the base 1 and a valve rod 5. The valve rod 5 is adapted for pushing the second blocking ball 4 in a sealing position for sealing the second communicating opening. The valve rod 5 is threadly coupled to the base 1. The simplification of the control switch can reduce costs. In use, the valve rod 5 pushes the second blocking ball 4 in the sealing position so that the second communicating opening is sealed. The valve rod 5 is screwed to release the second blocking ball 4, and the fluid pushes the second blocking ball 4 upwards so that the second communicating opening is open.
[0024] In actual design, the liquid returning cavity 12 is generally configured with a piston. The moving speed of the piston is controlled by the fluid flowing from the liquid returning cavity 12, and thus the descending speed of the jack is controlled by the piston.
[0025] In actual use, when the jack is no load, the valve rod 5 is screwed to release the second blocking ball 4. The first blocking ball 2 moves to the open position when the elastic force of the spring is larger than the hydraulic pressure of the hydraulic oil in the liquid returning cavity 12. The hydraulic oil flows from the liquid returning cavity 12 to the communicating cavity 13 through the first communicating opening 14 (referred to the arrow direction in FIG. 2), and further goes through the communicating cavity 13 to push the second blocking ball 4 upwards, and then flows into the liquid storing cavity 11. When the jack is on load, the valve rod 5 is screwed to release the blocking ball 4. The first blocking ball 2 is in blocking position when the elastic force of the spring is smaller than the hydraulic pressure of the hydraulic oil in the liquid returning cavity 12. The hydraulic oil flows into the communicating cavity 13 through the liquid guiding gap 15 (referred to the arrow direction in FIG. 3), and pushes the second blocking ball 4 upwards, and then flows into the liquid returning cavity 11. Therefore, the jack slows down.
[0026] Fig. 4 shows a construction schematic diagram of a second embodiment of the present invention. The difference between the FIG. 4 and the FIG. 1 is the installation how the valve rod 5 coupled to the base 1. In FIG. 1, the valve rod 5 is vertically and threadly coupled to the base 1. In FIG. 4, the valve rod 5 is obliquely and threadly coupled to the base 1. The installation how the valve rod 5 coupled to the base 1 is not limited only if the valve 5 can push the second blocking ball 4.
a base, a control switch, a first blocking ball mounted in the base, an elastic member mounted between the first blocking ball and the base; wherein the base has a liquid storing cavity, a liquid returning cavity, a communicating cavity, a first communicating opening communicating between the liquid returning cavity and the communicating cavity, and a second communicating opening communicating between the communicating cavity and the liquid storing cavity; the control switch is adapted for controlling the second communicating opening open or closed so that the communicating cavity and the liquid storing cavity are connected or separated; the first blocking ball moves between a blocking position and an open position with an external force; when the first blocking ball is in the open position, the whole first communicating opening is open, and thus a fluid flows from the liquid returning cavity to the communicating cavity; the first communicating opening is positioned in a communicating portion of the base; when the first blocking ball is in the blocking position, one or more liquid guiding gaps are formed between the first blocking ball and the communicating portion of the base; and the liquid guiding gap communicates between the liquid returning cavity and the communicating cavity.