Grease gun head and grease gun having the same

Abstract

The present application discloses a grease gun head, comprising: a barrel connection portion, used to connect the barrel; a plunger cavity, in which a plunger rod is installed, and the plunger rod can reciprocate along its axial direction; a first one-way valve, which connects the barrel connection portion with the plunger cavity; an oil pipe connection portion, used to connect the oil pipe; a second one-way valve, which connects the plunger cavity with the oil pipe connection portion; the plunger rod is used to press the medium in the plunger cavity into the oil pipe connection portion. The present application also discloses a grease gun, which includes the grease gun head as described above. The present application cleverly isolates the high-pressure oil in the oil pipe from the low-pressure oil in the barrel through a two-stage one-way valve. By manually pressing the rod, the output pressure of the oil pipe can be easily achieved to reach more than 100MPa, and zero-pressure removal of the oil pipe and the equipment can be achieved; the output pressure value of the gun head can be adjusted; and the air in the gun head can be discharged.

Description

Technical Field

[0001] The present application relates to the technical field of grease guns, and in particular to a grease gun head and a grease gun having the same. Background Art

[0002] A grease gun is a hand tool used to add grease to mechanical equipment. The grease guns currently used on the market generally consist of several parts, including an oil storage barrel, an oil push plug, a pressure rod, a gun head, and an oil pipe. The gun head of a grease gun is equivalent to a plunger pump, which presses the grease in the oil storage barrel into the oil pipe and then injects it into the equipment that needs lubrication. However, the oil pressure of the grease gun can only reach 10 to 30 MPa, and the current oil injection pressure cannot be displayed. In addition, when the oil injection work is completed, it is necessary to remove the connection between the grease gun and the equipment. Due to the certain pressure in the oil pipe, forced disassembly can easily cause damage to the oil pipe and the equipment oil injection nozzle.

[0003] With the development of industrial technology, grease guns are not only used in the field of lubrication, but also in pressure equipment. However, pressure equipment requires higher pressure to complete the oil injection, and the existing grease guns cannot meet the use requirements. In addition, the existing grease guns do not have a pressure display device during use, and the oil injection pressure value cannot be determined. The existing grease guns do not have a pressure relief device. When the grease gun is separated from the equipment to be oiled, it is still in a high-pressure state, which makes it difficult to disassemble and there is a certain degree of danger.

[0004] Therefore, it is desired to have a technical solution to overcome or at least alleviate at least one of the above-mentioned defects of the prior art.

[0005] Application Contents

[0006] The object of the present application is to provide a grease gun head and a grease gun having the same to overcome or at least alleviate at least one of the above-mentioned defects of the prior art.

[0007] To achieve the above objectives, the present application provides a grease gun head, the grease gun head comprising:

[0008] Plunger rod;

[0009] A barrel connecting portion, used for connecting to a gun barrel;

[0010] A plunger cavity, in which the plunger rod is installed, and the plunger rod can reciprocate along its axial direction;

[0011] a first one-way valve, the first one-way valve connecting the barrel connecting portion and the plunger cavity; the first one-way valve is in an opening direction from the barrel connecting portion to the plunger cavity, and in a closing direction from the plunger cavity to the barrel connecting portion;

[0012] An oil pipe connecting part, used for connecting an oil pipe;

[0013] a second one-way valve, the second one-way valve connecting the plunger cavity and the oil pipe connecting portion; the direction of the second one-way valve from the plunger cavity to the oil pipe connecting portion is an opening direction, and the direction from the oil pipe connecting portion to the plunger cavity is a closing direction;

[0014] The plunger rod is used to press the medium in the plunger cavity into the oil pipe connecting part.

[0015] Preferably, the grease gun head further includes a pressure relief valve, which connects the oil pipe connection part and the gun barrel connection part; the pressure relief valve includes two states, closed and open, in which the oil pipe connection part and the gun barrel connection part are disconnected, and in the open state, the oil pipe connection part and the gun barrel connection part are connected, so as to return the medium in the oil pipe connection part to the gun barrel connection part.

[0016] Preferably, the pressure relief valve and the body of the grease gun head are an integrated structure, and the body of the grease gun head is provided with:

[0017] an oil outlet hole of a pressure relief valve, one end of which is connected to the gun barrel connecting portion;

[0018] an oil inlet hole of a pressure relief valve, one end of which is connected to the oil pipe connecting portion;

[0019] a first mounting hole;

[0020] The other ends of the pressure relief valve oil outlet hole and the pressure relief valve oil inlet hole are both connected to the first mounting hole;

[0021] A first steel ball and a first screw are installed in the first mounting hole. The first screw is threadedly matched with the first mounting hole and its axis coincides with the axis of the oil inlet hole of the pressure relief valve. The first screw presses the first steel ball against the port of the oil inlet hole of the pressure relief valve to control the opening and closing of the pressure relief valve.

[0022] Preferably, the grease gun head further includes a relief valve, which connects the barrel connecting part and the plunger cavity; the relief valve is in a normally closed state when the grease gun is filled with oil, and when the pressure in the plunger cavity exceeds the set pressure of the relief valve, the relief valve opens, and the medium in the plunger cavity flows back to the barrel connecting part through the relief valve.

[0023] Preferably, the overflow valve and the body of the grease gun head are an integrated structure, and the body of the grease gun head is provided with:

[0024] An oil inlet hole of a relief valve, one end of which is connected to the plunger cavity;

[0025] an oil outlet hole of a relief valve, one end of which is connected to the gun barrel connecting portion;

[0026] Second mounting hole;

[0027] The other ends of the overflow valve oil inlet hole and the overflow valve oil outlet hole are both connected to the second mounting hole;

[0028] A second steel ball, a second compression spring and a screw plug are installed in the second mounting hole. One end of the second compression spring is pressed against the screw plug, and the other end presses the second steel ball against the port of the oil inlet hole of the overflow valve, so that the oil inlet hole of the overflow valve and the oil outlet hole of the overflow valve are in a normally closed state.

[0029] Preferably, the grease gun head further comprises an exhaust valve, which is connected to the plunger cavity. The exhaust valve is in a normally closed state when the grease gun is filled with oil, and when the exhaust valve is in an open state, the plunger cavity is connected to the atmosphere.

[0030] Preferably, a third mounting hole and an exhaust connecting hole are provided on the main body of the grease gun head, and the third mounting hole is connected with the plunger cavity through the exhaust connecting hole; the exhaust valve comprises a valve body, a third steel ball and a third screw, and the valve body is mounted on the third mounting hole, and the valve body is provided with an air inlet hole and an air outlet hole with perpendicular axes, and the third screw is used to push the third steel ball against the port of the air inlet hole to control the connection or closing of the air inlet hole and the air outlet hole.

[0031] Preferably, the grease gun head further comprises a pressure gauge, which is connected to the oil pipe connecting portion and is used to display the pressure in the oil pipe.

[0032] Preferably, a copper sleeve is installed between the plunger cavity and the plunger rod.

[0033] The present application also provides a grease gun, which comprises the grease gun head as described above.

[0034] The beneficial effects of this application are:

[0035] The present application ingeniously isolates the high-pressure oil in the oil pipe from the low-pressure oil in the gun barrel through a two-stage one-way valve, and the two do not interfere with each other. By manually operating the lever, the output pressure of the oil pipe can be easily achieved to be above 100MPa. In addition, the grease gun head of the present application is also provided with a pressure relief valve, which can achieve zero-pressure removal of the oil pipe and the equipment; an overflow valve, which can adjust the output pressure value of the gun head; and an exhaust valve, which can discharge the air in the gun head to ensure a stable output pressure value. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a schematic structural diagram of a grease gun head provided in one embodiment of the present application.

[0037] Figure 2 It is a schematic structural diagram of a pressure relief valve of a grease gun head provided in a second embodiment.

[0038] Figure 3 It is a schematic structural diagram of the overflow valve of the grease gun head provided in the third embodiment.

[0039] Figure 4 It is a schematic structural diagram of an exhaust valve of a grease gun head provided in a fourth embodiment.

[0040] Figure 5 It is another structural schematic diagram of a grease gun head provided by the fourth embodiment.

[0041] Figure 6 It is a structural schematic diagram of a grease gun provided in this application.

[0042] 1-gun barrel; 2-oil push plug; 3-pressure rod; 4-gun head; 5-pressure gauge; 6-tee joint; 7-oil pipe; 8-second one-way valve; 9-fourth compression spring; 10-fourth steel ball; 11-first one-way valve; 12-gun barrel connecting part; 13-body; 14-plunger rod; 15-plunger chamber; 16-oil pipe connecting part; 17-first mounting hole; 18-second mounting hole; 19-third mounting hole; 21-oil outlet hole of overflow valve; 22-oil outlet hole of pressure relief valve; 23-oil inlet hole of pressure relief valve; 24-first steel ball; 25-first screw; 26-third screw; 27-air outlet hole; 28-third steel ball; 29-valve body; 30 exhaust connection hole; 31-second compression spring; 32-screw plug; 33-oil inlet hole of overflow valve; 34-second steel ball; 35-air inlet hole. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical scheme and advantages of the implementation of this application clearer, the technical scheme in the embodiment of this application will be described in more detail below in conjunction with the drawings in the embodiment of this application. In the drawings, the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The described embodiments are part of the embodiments of this application, not all of them. The embodiments described below with reference to the drawings are exemplary and are intended to be used to explain this application, and should not be construed as limitations on this application. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application. The embodiments of this application are described in detail below in conjunction with the drawings.

[0044] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the scope of protection of the present application.

[0045] Embodiment 1:

[0046] like Figure 1 As shown, in this embodiment, the grease gun head includes a body 13 of the head, and a barrel connecting portion 12 is provided on the body 13 for connecting to the barrel, and the barrel connecting portion 12 is connected to the barrel by threads.

[0047] The main body 13 of the gun head is also provided with a plunger cavity 15, the axis of which is perpendicular to the axis of the barrel connecting portion 12. The plunger cavity 15 is used to install a plunger rod 14, which can reciprocate along its axis.

[0048] It is understandable that a copper sleeve can also be installed in the plunger cavity 15. For example, in an alternative embodiment, a copper sleeve is installed in the plunger cavity 15, and the axis of the copper sleeve coincides with the axis of the plunger cavity 15. The plunger rod 14 is installed in the copper sleeve, and the plunger rod 14 can reciprocate along its axis in the copper sleeve. The advantage is that direct friction between the plunger rod 14 and the body 13 of the gun head can be avoided, and when the plunger rod 14 or the copper sleeve is worn, the copper sleeve can be replaced separately.

[0049] A first one-way valve 11 is installed on the main body 13 of the gun head. The first one-way valve 11 includes a valve body, which is fixedly connected to the main body 13 by threads. The center of the valve body is set as a through hole with a tapered hole section. A compression spring and a steel ball are installed in the valve body. One end of the compression spring is fixed, and the other end pushes the steel ball against the tapered hole section to form a one-way oil circuit; the first one-way valve 11 connects the barrel connecting part 12 and the plunger cavity 15; the direction of the first one-way valve 11 from the barrel connecting part 12 to the plunger cavity 15 is the opening direction, and the direction from the plunger cavity 15 to the barrel connecting part 12 is the closing direction; after the grease in the barrel reaches the barrel connecting part 12, the pressure of the compression spring on the steel ball is overcome to open the one-way valve, and the grease in the barrel connecting part 12 enters the plunger cavity 15.

[0050] The main body 13 of the gun head is also provided with an oil pipe connection part 16, which is used to connect an oil pipe to inject grease into the device. The axis of the oil pipe connection part 16 is parallel to the axis of the barrel connection part 12 and perpendicular to the axis of the plunger cavity 15.

[0051] A second one-way valve 8 is also provided on the main body 13 of the gun head. The second one-way valve 8 and the main body 13 are an integral structure. A threaded hole with a tapered hole section is provided on the main body 13, and the threaded hole with the tapered hole section is connected with the plunger cavity 15 in the small section of the tapered hole section; the second one-way valve 8 also includes a valve body, a fourth compression spring 9 and a fourth steel ball 10. The valve body is fixedly connected to the main body 13 by threads, one end of the fourth compression spring 9 is pressed against the valve body, and the other end presses the fourth steel ball 10 against the tapered hole section to realize one-way flow of the oil circuit.

[0052] The second one-way valve 8 connects the plunger cavity 15 and the oil pipe connection part 16; the direction of the second one-way valve 8 from the plunger cavity 15 to the oil pipe connection part 16 is the opening direction, and the direction from the oil pipe connection part 16 to the plunger cavity 15 is the closing direction; the grease in the plunger cavity 15 can be opened by the pressure of the fourth compression spring 9 on the fourth steel ball 10 under the pressure of the plunger rod 14, so that the grease in the plunger cavity 15 enters the oil pipe connection part 16 and then enters the oil pipe. It can be understood that the oil pipe can be a hose or a steel hard pipe.

[0053] The present application ingeniously isolates the high-pressure oil in the oil pipe from the low-pressure oil in the gun barrel through the first one-way valve 11 and the second one-way valve 8, so that the two do not interfere with each other. By manually operating the pressure rod, the output pressure of the oil pipe can be easily achieved to reach above 100MPa.

[0054] Embodiment 2:

[0055] like Figure 2 As shown, in this embodiment, based on the first embodiment, the grease gun head further includes a pressure relief valve, which connects the oil pipe connection part 16 and the gun barrel connection part 12; the pressure relief valve includes two states, closed and open. In the closed state, the oil pipe connection part 16 and the gun barrel connection part 12 are disconnected, and in the open state, the oil pipe connection part 16 and the gun barrel connection part 12 are connected, so as to return the medium in the oil pipe connection part 16 to the gun barrel connection part 12.

[0056] Specifically, the pressure relief valve in this embodiment is an integrated structure with the body of the grease gun head, and the body of the grease gun head is provided with:

[0057] a pressure relief valve oil outlet hole 22 connected to the barrel connection portion 12 at one end;

[0058] A pressure relief valve oil inlet hole 23 connected to the oil pipe connection portion 16 at one end;

[0059] A first mounting hole 17;

[0060] The other ends of the pressure relief valve oil outlet hole 22 and the pressure relief valve oil inlet hole 23 are both connected to the first mounting hole;

[0061] A first steel ball 24 and a first screw 25 are installed in the first mounting hole. The first screw 25 is threadedly matched with the first mounting hole and its axis coincides with the axis of the oil inlet hole 23 of the pressure relief valve. The first screw 25 presses the first steel ball 24 against the port of the oil inlet hole 23 of the pressure relief valve to control the opening and closing of the pressure relief valve.

[0062] When the gun head outputs grease, the pressure relief valve is in a closed state. When the connection between the grease gun and the equipment needs to be removed, in order not to damage the oil pipe and the oil filling joint on the equipment, the high pressure in the oil pipe can be released through the pressure relief valve. That is, after the screw pressure of the first steel ball 24 is released by turning the first screw 25, the first steel ball 24 leaves the port of the oil inlet 23 of the pressure relief valve under the action of the oil pressure in the oil inlet hole 23 of the pressure relief valve, and the pressure relief valve opens, and the high-pressure grease in the oil pipe enters the gun barrel connecting part 12 through the pressure relief valve.

[0063] The advantage of adding the pressure relief valve in this embodiment is that it can achieve zero-pressure removal of the oil pipe and the equipment, which is beneficial to protecting the connection joints between the oil pipe and the equipment.

[0064] Embodiment three:

[0065] like Figure 3 As shown, in this embodiment, based on the above-mentioned embodiment 2, the grease gun head further includes a relief valve, which connects the barrel connecting part 12 and the plunger cavity 15; the relief valve is in a normally closed state when the grease gun is filled with oil. When the pressure in the plunger cavity 15 exceeds the set pressure of the relief valve, the relief valve opens, and the medium in the plunger cavity 15 flows back to the barrel connecting part 12 through the relief valve.

[0066] Specifically, in this embodiment, the overflow valve and the body of the grease gun head are an integrated structure, and the body 13 of the grease gun head is provided with:

[0067] An overflow valve oil inlet hole 33 connected to the plunger chamber 15 at one end;

[0068] A relief valve oil outlet hole 21 having one end connected to the barrel connecting portion 12;

[0069] A second mounting hole 18;

[0070] The other ends of the overflow valve oil inlet hole 33 and the overflow valve oil outlet hole 21 are both connected to the second mounting hole;

[0071] A second steel ball 34, a second compression spring 31 and a screw plug 32 are installed in the second mounting hole. One end of the second compression spring 31 is pressed against the screw plug 32, and the other end of the second steel ball 34 is pressed against the port of the overflow valve oil inlet hole 33, so that the overflow valve oil inlet hole 33 and the overflow valve oil outlet hole 21 are in a normally closed state.

[0072] When the gun head outputs grease outward, the relief valve is in a closed state. When the oil pressure in the plunger chamber 15 exceeds the pressure value set by the relief valve, the oil pressure in the oil inlet hole 33 of the relief valve will overcome the force of the second compression spring 31, lift the second steel ball 34, and the relief valve opens. The high-pressure oil in the plunger chamber 15 flows back to the gun barrel connecting part 12 through the relief valve, thereby no longer outputting grease outward.

[0073] It is understandable that the return pressure value of the overflow valve can be adjusted by adjusting the pressure of the second compression spring 31. For example, in this embodiment, the compression amount of the second compression spring 31 can be controlled by adjusting the position of the screw plug 32, thereby controlling the pressure applied by the second compression spring 31 to the second steel ball 34.

[0074] The advantage of this embodiment is that, by adding the overflow valve, it is possible to prevent workers' erroneous operations from causing damage to the equipment, thereby playing a role of automatic protection.

[0075] Embodiment 4:

[0076] like Figure 4 , Figure 5 As shown, in this embodiment, based on the third embodiment, the grease gun head further includes an exhaust valve, which is connected to the plunger chamber 15. The exhaust valve is normally closed when the grease gun is filled with oil. When the exhaust valve is open, the plunger chamber 15 is connected to the atmosphere through the exhaust valve.

[0077] Specifically, a third mounting hole and an exhaust connection hole 30 are provided on the main body 13 of the grease gun head, and the third mounting hole 19 is connected with the plunger cavity 15 through the exhaust connection hole 30; the exhaust valve includes a valve body 29, a third steel ball 28 and a third screw 26, the valve body 29 is installed on the third mounting hole, and the valve body 29 is provided with an air inlet hole 35 and an air outlet hole 27 with vertical axes, and the third screw 26 is used to push the third steel ball 28 against the port of the air inlet hole 35 to control the connection or closing of the air inlet hole 35 and the air outlet hole 27.

[0078] When the gun head discharges grease outward, the exhaust valve is in a closed state. During the oil filling process, if the pressure rod of the grease gun is weak or the oil discharge is abnormal, you can try to open the exhaust valve to release the air in the plunger cavity 15. When grease is continuously discharged from the air outlet 27, it means that the internal gas has been exhausted. At this time, you can close the exhaust valve and continue to discharge grease outward.

[0079] The advantage of this embodiment is that an exhaust valve is provided to exhaust the air in the gun head, thereby ensuring a stable output pressure value.

[0080] Embodiment five:

[0081] This embodiment is based on the fourth embodiment, and the grease gun head further includes a pressure gauge, which is connected to the oil pipe connecting part 16 and is used to display the pressure in the oil pipe. Its advantage is that it can display the current oil outlet pressure value in the oil pipe, which is convenient for understanding the current oil filling situation.

[0082] In this embodiment, the grease gun head is equipped with a three-way joint at the oil pipe connection part 16, one outlet of the three-way joint is connected to the oil pipe connection part 16, one outlet is used to connect the oil pipe, and one outlet is used to install the pressure gauge.

[0083] Embodiment 6:

[0084] like Figure 6 As shown, the present application provides a grease gun, which includes a gun barrel 1, an oil push plug 2, a pressure rod 3, a gun head 4, a pressure gauge 5, a three-way joint 6 and an oil pipe 7. The gun head 4 can be any one of the above five embodiments.

[0085] It is understandable that when the gun tip in Example 5 is used, since the gun tip in Example 5 already includes a pressure gauge, there is no need to add a pressure gauge and a three-way connector.

[0086] By using the above-mentioned grease gun head, the grease gun can realize zero-pressure removal of the oil pipe and the equipment; the output pressure value of the gun head can be adjusted; and the air in the gun head can be discharged to ensure a stable output pressure value.

[0087] In this embodiment, the gun barrel 1, the oil push plug 2, the pressure rod 3 and the oil pipe 7 are the same as those in the prior art and will not be described in detail herein.

[0088] Finally, it should be pointed out that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application is described in detail with reference to the above embodiments, a person skilled in the art should understand that the technical solutions described in the above embodiments can still be modified, or some of the technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A grease gun head, characterized in that: include: A plunger rod (14); A gun barrel connecting portion (12), used for connecting to the gun barrel; A plunger cavity (15), wherein the plunger cavity (15) is used to mount the plunger rod (14), and the plunger rod (14) is capable of reciprocating motion along its axial direction; a first one-way valve (11), the first one-way valve connecting the barrel connecting portion (12) and the plunger chamber (15); the direction of the first one-way valve (11) from the barrel connecting portion (12) to the plunger chamber (15) is an opening direction, and the direction from the plunger chamber (15) to the barrel connecting portion (12) is a closing direction; An oil pipe connecting portion (16), used for connecting an oil pipe; a second one-way valve (8), the second one-way valve connecting the plunger cavity (15) and the oil pipe connecting portion (16); the direction of the second one-way valve (8) from the plunger cavity (15) to the oil pipe connecting portion (16) is an opening direction, and the direction from the oil pipe connecting portion (16) to the plunger cavity (15) is a closing direction; The plunger rod (14) is used to press the medium in the plunger cavity (15) into the oil pipe connecting portion (16); The grease gun head further comprises a pressure relief valve, which connects the oil pipe connection part (16) and the gun barrel connection part (12); the pressure relief valve comprises two states, a closed state and an open state; in the closed state, the oil pipe connection part (16) and the gun barrel connection part (12) are disconnected; in the open state, the oil pipe connection part (16) and the gun barrel connection part (12) are connected, and is used to return the medium in the oil pipe connection part (16) to the gun barrel connection part (12); The pressure relief valve and the body of the grease gun head are an integrated structure, and the body of the grease gun head is provided with: A pressure relief valve oil outlet hole (22) having one end connected to the gun barrel connecting portion (12); An oil inlet hole (23) of a pressure relief valve, one end of which is in communication with the oil pipe connection portion (16); A first mounting hole (17); The other ends of the pressure relief valve oil outlet hole (22) and the pressure relief valve oil inlet hole (23) are both connected to the first mounting hole; A first steel ball (24) and a first screw (25) are installed in the first mounting hole. The first screw is threadably matched with the first mounting hole and its axis coincides with the axis of the oil inlet hole (23) of the pressure relief valve. The first screw presses the first steel ball (24) against the port of the oil inlet hole (23) of the pressure relief valve to control the opening and closing of the pressure relief valve.

2. The grease gun head according to claim 1, characterized in that: The grease gun head further comprises a relief valve, which is connected to the barrel connection portion (12) and the plunger chamber (15); the relief valve is in a normally closed state when the grease gun is filled with oil, and when the pressure in the plunger chamber (15) exceeds a set pressure of the relief valve, the relief valve opens, and the medium in the plunger chamber (15) flows back to the barrel connection portion (12) through the relief valve.

3. The grease gun head according to claim 2, characterized in that: The overflow valve and the body of the grease gun head are an integrated structure, and the body of the grease gun head is provided with: An overflow valve oil inlet hole (33) having one end in communication with the plunger cavity (15); An overflow valve oil outlet hole (21) having one end connected to the gun barrel connecting portion (12); A second mounting hole (18); The other ends of the overflow valve oil inlet hole (33) and the overflow valve oil outlet hole (21) are both connected to the second mounting hole; A second steel ball (34), a second compression spring (31) and a screw plug (32) are installed in the second installation hole. One end of the second compression spring (31) is pressed against the screw plug (32), and the other end of the second steel ball is pressed against the port of the overflow valve oil inlet hole (33), so that the overflow valve oil inlet hole (33) and the overflow valve oil outlet hole (21) are in a normally closed state.

4. The grease gun head according to claim 3, characterized in that: The grease gun head further comprises an exhaust valve, which is connected to the plunger chamber (15). The exhaust valve is in a normally closed state when the grease gun is filled with oil, and when the exhaust valve is in an open state, the plunger chamber (15) is connected to the atmosphere.

5. The grease gun head according to claim 4, characterized in that: The body of the grease gun head is provided with a third mounting hole (19) and an exhaust connection hole (30), and the third mounting hole is connected to the plunger cavity (15) through the exhaust connection hole (30); the exhaust valve comprises a valve body (29), a third steel ball (28) and a third screw (26), and the valve body (29) is installed on the third mounting hole. The valve body (29) is provided with an air inlet hole (35) and an air outlet hole (27) with vertical axes, and the third screw (26) is used to push the third steel ball (28) against the end of the air inlet hole (35) to control the connection or closing of the air inlet hole (35) and the air outlet hole (27).

6. The grease gun head according to claim 5, characterized in that: The grease gun head further comprises a pressure gauge, which is connected to the oil pipe connecting portion (16) and is used to display the pressure in the oil pipe.

7. The grease gun head according to claim 6, characterized in that: A copper sleeve is installed between the plunger cavity (15) and the plunger rod (14).

8. A grease gun, characterized in that: The grease gun comprises a grease gun head as described in any one of claims 1 to 7.

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