CN107215803B - Oil pressure type jack - Google Patents

Abstract

The invention provides an oil pressure type jack, which comprises: an oil tank; an oil cylinder assembly; the jack comprises a jack body, wherein an oil inlet with a first outlet and a second outlet, an oil outlet channel communicated with an oil cylinder assembly and the first outlet, and an oil return channel communicated with the oil outlet channel and the second outlet are formed in the jack body; the oil pump assembly is arranged on the jack body and comprises a pump core; the pedal rod is hinged on the jack body and connected with the pump core, the pump core can be driven to move by manually or foot-stepping the pedal rod, and the oil pump assembly is driven to guide oil in the oil tank into the oil inlet by utilizing the atmospheric pressure principle; and the switch valve is integrated in the jack body and matched with the oil return channel, the switch valve is used for opening and closing the oil return channel, the oil outlet channel is disconnected from the second outlet and communicated with the first outlet when the oil return channel is closed, and the oil outlet channel is disconnected from the first outlet and communicated with the second outlet when the oil return channel is opened. The oil pressure type jack has the advantages of compact layout and good stability.

Description

A hydraulic jack

technical field

The invention belongs to the technical field of machinery, and relates to a hydraulic jack, in particular to a manual/pedal hydraulic jack.

Background technique

In the prior art, platform vehicles such as manual platform trucks and manual pallet trucks are widely used with jack structures. At present, there are also hydraulic jack structures, but the structure is simple and needs to be provided outside the jack for auxiliary control platform lift. The lifting and lowering switch device reduces the stability of the whole vehicle, takes up more space, and increases the production cost.

In summary, it is necessary to design a hydraulic jack with a compact layout and good stability.

SUMMARY OF THE INVENTION

The purpose of the present invention is to solve the above problems in the prior art, and propose a hydraulic jack with compact layout and good stability.

The object of the present invention can be achieved through the following technical solutions: a hydraulic jack, comprising:

tank;

Cylinder assemblies for lifting or lowering operations;

The jack body is provided with an oil inlet with a first outlet and a second outlet, an oil outlet channel connecting the oil cylinder assembly and the first outlet, and an oil return channel connecting the oil outlet channel and the second outlet;

an oil pump assembly, which is arranged on the jack body and includes a pump core;

The foot lever is hinged on the jack body and connected with the pump core. The displacement of the pump core can be driven by stepping on the foot lever manually or by foot, and the oil pump assembly is driven to introduce the oil in the oil tank into the oil inlet by using the principle of atmospheric pressure;

The switch valve is integrated in the jack body and is adapted to the oil return passage. The switch valve is used to open and close the oil return passage. When the oil return passage is closed, the oil outlet passage is disconnected from the second outlet and is connected to the first outlet. An outlet is connected, and when the oil return channel is opened, the oil outlet channel is disconnected from the first outlet and connected to the second outlet.

As a further improvement of the present invention, an oil outlet valve is provided at the butt joint of the oil outlet channel and the first outlet. When the oil outlet channel returns oil, the returning oil pushes the oil outlet valve and makes it block the above-mentioned butt joint. When the oil outlet channel is disconnected from the first outlet.

As a further improvement of the present invention, the oil outlet valve includes an oil outlet steel ball connected to the jack body through an oil outlet pressure spring. When the oil is returned to the oil outlet channel, the returning oil pushes the oil outlet steel ball and seals it. The butt joint of the oil outlet channel and the first outlet is blocked, and the oil outlet channel is disconnected from the first outlet at this time.

As a further improvement of the present invention, the on-off valve comprises a hollow switch jacket inserted in the jack body, a switch valve core axially movably installed in the middle of the switch jacket and partially extending out of the jack body, and connected to the on-off valve The switch wrench at the end of the core away from the jack body, a torsion spring is arranged between the switch wrench and the jack body, and a switch channel for connecting the oil return channel and the second outlet is arranged in the middle of the switch jacket, and the switch wrench can be controlled to drive the switch valve core Displace and switch the channel on or off.

As a further improvement of the present invention, a switch steel ball is arranged at the butt joint of the switch channel and the oil return channel, and the switch wrench can be manipulated to drive the axial displacement of the switch valve core. Press the switch steel ball against the above joint or disengage it from the switch steel ball.

As a further improvement of the present invention, the oil inlet is also provided with a third outlet, the jack body is also provided with an oil inlet channel connected with the first outlet, an overload protection channel connected with the third outlet, and a connection port. The connection port is respectively communicated with the oil inlet channel, the oil outlet channel and the overload protection channel. An oil inlet valve is arranged at the butt joint of the connection port and the oil inlet channel, and the oil outlet valve is arranged at the butt joint of the connection port and the oil outlet channel. The jack body is provided with a safety valve adapted to the overload protection channel and the safety valve is a one-way safety valve, the safety valve is used to open and close the overload protection channel, and the oil inlet valve is opened when the oil inlet channel is fed. At this time, the safety valve closes the overload protection channel, and the third outlet is disconnected from the connection port. When overloaded, the oil flows back and closes the oil outlet valve. At this time, the oil in the oil inlet channel passes through the connection port and pushes open the safety valve. valve, the overload protection channel is opened, and the oil flows back to the oil tank through the overload protection channel and the third outlet.

As a further improvement of the present invention, the second outlet and the third outlet are arranged on both sides of the first outlet and are located in the middle of the oil inlet, the first outlet is arranged at the lower position of the oil inlet, and the inlet The oil channel is arranged vertically, the oil outlet channel is arranged horizontally, the overload protection channel is arranged vertically, and the connection port is located below the first outlet.

As a further improvement of the present invention, the oil inlet valve includes an oil inlet steel ball connected to the jack body through an oil inlet pressure spring, and the oil inlet steel ball is blocked at the oil inlet passage and the oil inlet passage by the elastic force of the oil inlet pressure spring. At the butt joint of the connection port, when the oil inlet channel enters the oil, the oil pushes the oil inlet steel ball and connects the oil inlet channel and the connection port.

As a further improvement of the present invention, the safety valve includes an overload steel ball, a compression mechanism for compressing the overload steel ball on the butt joint of the overload protection channel and the connection port, and the compression mechanism includes a connection with the overload steel ball. When overloaded, the oil in the oil inlet channel will pass through the connection port and push the overload steel ball away, and the overload protection channel will be opened.

As another improvement of the present invention, an oil pipe joint for connecting the oil outlet channel and the oil cylinder assembly is detachably installed on the jack body, and the oil pipe joint part extends into the oil outlet channel and is connected with the oil outlet pressure spring.

Based on the above technical solutions, the embodiments of the present invention can at least produce the following technical effects:

1. The overall structure is compact and the on-off valve is directly integrated into the jack, eliminating the need for an external switch device to control the lifting and lowering of the platform, which can well ensure the stability of the vehicle and saves money to a certain extent. Cost; the foot lever, oil pump assembly, jack body, oil cylinder assembly, etc. are closely matched, which can reliably complete the lifting work of the platform vehicle, and the three-stage split hydraulic system of the oil pump, jack, and oil cylinder is used. Compared with other platforms The hydraulic system of the vehicle is more conducive to maintenance and inspection. At the same time, the jack is small and light, suitable for light platform series models.

2. The overall hydraulic jack works reliably and stably. By stepping on the foot lever, the oil in the fuel tank starts to flow into the jack from the oil inlet due to the principle of atmospheric pressure. At this time, the switch valve closes the oil return channel, the oil outlet channel and the first The second outlet is disconnected, so the oil can only enter the oil outlet channel from the first outlet and finally enter the cylinder assembly, thereby completing the lifting operation of the platform; when the switch valve is opened, the oil return channel is opened, and the oil outlet channel and the second outlet On, the oil cylinder assembly starts to return the oil under the gravity of the heavy object and the oil itself. At this time, the oil outlet channel and the first outlet are disconnected, and the returned oil can only flow back to the oil outlet channel through the oil return channel and the second outlet. The oil inlet, and finally flows back to the oil tank to complete the descending operation of the platform.

Description of drawings

The specific embodiments of the present invention will be described in further detail below in conjunction with the accompanying drawings, wherein:

FIG. 1 is a schematic structural diagram of a preferred embodiment of the present invention.

FIG. 2 is a schematic structural diagram of FIG. 1 from another perspective.

In the figure, 10, jack body; 11, oil inlet; 111, first outlet; 112, second outlet; 113, third outlet; 12, oil outlet channel; 13, oil return channel; 14, oil inlet channel; 15, overload protection channel; 16, connection port; 161, oil discharge port; 20, oil pump assembly; 21, pump core; 30, foot lever; 40, switch valve; 41, switch cover; 411, switch channel; 42, Switch valve core; 43, switch wrench; 44, torsion spring; 45, switch steel ball; 46, set screw; 50, oil outlet valve; 51, oil outlet pressure spring; 52, oil outlet steel ball; 60, oil inlet Valve; 61, oil inlet pressure spring; 62, oil inlet steel ball; 70, safety valve; 71, overload steel ball; 72, overload pressure spring; 73, sheath; 74, adjusting screw; 75, sealing ring; 80, Oil discharge valve; 90, oil pipe joint.

Detailed ways

The following are specific embodiments of the present invention and the accompanying drawings to further describe the technical solutions of the present invention, but the present invention is not limited to these embodiments.

The technical solutions provided by the present invention will be described in more detail below with reference to FIG. 1 to FIG. 2 .

As shown in Figure 1 and Figure 2, this hydraulic jack includes:

A fuel tank (not shown in the figure), which stores fluid oil;

The oil cylinder assembly (not shown in the figure) is used to complete the lifting or lowering of the platform of the vehicle;

The jack body 10, as a main support carrier, is provided with an oil inlet 11 having a first outlet 111 and a second outlet 112, an oil outlet channel 12 communicating with the cylinder assembly and the first outlet 111, and communicating oil The oil return channel 13 of the channel 12 and the second outlet 112, the inlet of the oil inlet 11 is connected to the oil tank;

The oil pump assembly 20 is arranged on the jack body 10 and includes a movably arranged pump core 21;

The foot lever 30 is preferably hinged on the jack body 10 and connected with the pump core 21 through a pin, and the pump core 21 can be driven to displace by stepping on the foot lever 30 manually or by foot, and the oil pump assembly 20 can be driven by the principle of atmospheric pressure. The oil is introduced into the oil inlet 11;

The switch valve 40 is integrated in the jack body 10 and is adapted to the oil return passage 13. The switch valve 40 is used to open and close the oil return passage 13. When the oil return passage 13 is closed, the oil outlet passage 12 is connected to the oil return passage 13. The second outlet 112 is disconnected and connected to the first outlet 111. When the oil return channel 13 is opened, the oil outlet channel 12 is disconnected from the first outlet 111 and connected to the second outlet 112; that is, the on-off valve 40 can be opened to return to The oil passage 13 conducts the oil outlet passage 12 and the second outlet 112. At this time, the oil outlet passage 12 and the first outlet 111 are disconnected. The switch valve 40 can also close the oil return passage 13. At this time, the oil outlet passage 12 and the first outlet are disconnected. The outlet 111 is turned on, and the oil outlet channel 12 and the second outlet 112 are disconnected.

The present invention protects a hydraulic jack, which can be a manual hydraulic jack/pedal hydraulic jack, preferably a foot hydraulic jack, which is compact and lightweight, and is suitable for portable platform series models.

In the present invention, the oil tank and the oil cylinder assembly may belong to a part of other parts of the platform vehicle, or may be a part of the hydraulic jack of the present invention.

The above-mentioned oil pump assembly 20 also preferably includes a hydraulic oil pump body, so that the oil pump assembly 20, the foot lever 30 and the oil tank constitute the power unit of the hydraulic system of the present invention, and the above-mentioned foot lever 30 is directly connected to the jack through the pin shaft, and is connected to the oil pump assembly 20. The pump core 21 is in direct contact, and the mechanical energy generated by stepping on or manually operating the foot lever 30 is converted into the pressure of the oil and can directly enter the jack from the oil tank, wherein the oil pump assembly 20 is preferably threadedly connected to the jack body 10, which can be easily disassembled and maintained. .

The overall structure and layout of the hydraulic jack is compact, and the switch valve 40 is directly integrated into the jack, eliminating the need for an external switch device to control the lifting and lowering of the platform, which can well ensure the stability of the whole vehicle. The cost is saved to a certain extent; the foot lever 30, the oil pump assembly 20, the jack body 10, the oil cylinder assembly, etc. are closely matched, and the lifting work of the platform vehicle can be reliably completed, and the present invention adopts the oil pump, the jack, and the oil cylinder. Compared with the hydraulic system of other platform vehicles, the hydraulic system of the vehicle is more conducive to maintenance and inspection. At the same time, the jack is small and light, which is suitable for the light platform series models.

The hydraulic jack works reliably and stably. The lifting and lowering principle of the control platform is as follows: step on the foot lever 30, let the oil in the fuel tank flow into the jack from the oil inlet 11 due to the principle of atmospheric pressure, and then switch the The valve 40 closes the oil return channel 13, and the oil outlet channel 12 and the second outlet 112 are disconnected, so the oil can only enter the oil outlet channel 12 from the first outlet 111 and finally enter the oil cylinder assembly, thereby completing the lifting operation of the platform; when After the switch valve 40 is opened, the oil return channel 13 is opened, the oil outlet channel 12 and the second outlet 112 are connected, and the oil cylinder assembly starts to return the oil under the gravity of the heavy object and the oil. At this time, the oil outlet channel 12 and the first outlet 111 is disconnected, and the returned oil can only flow back to the oil inlet 11 from the oil outlet channel 12 through the oil return channel 13 and the second outlet 112, and finally flow back to the oil tank to complete the descending operation of the platform.

It is worth mentioning that: when the jack of the present invention is applied to a platform vehicle, the lowering of the vehicle platform is realized by opening the switch valve 40 and cooperating with the weight of the platform, heavy objects, and oil, that is, the oil is obtained under the action of gravity. The oil return power is not operated by pumping the oil back into the oil tank, and the structural design is ingenious to ensure the stability of the working process.

Further, in order to make the overall work more reliable and ensure the reliability of the oil return operation (that is, the platform lowering operation), an oil outlet valve 50 is provided at the connection between the oil outlet channel 12 and the first outlet 111, and the oil outlet channel 12 returns to the first outlet 111. When oil is used, the returning oil pushes the oil outlet valve 50 to block the above-mentioned butt joint. At this time, the oil outlet channel 12 is disconnected from the first outlet 111, and the returning oil can only flow back through the return channel through the second outlet 112. To the oil inlet 11 and finally back to the oil tank, the oil outlet valve 50 acts like a one-way valve; when oil is fed into the oil outlet channel 12, the oil flowing out of the first outlet 111 pushes the oil outlet valve 50 and enters the oil cylinder through the oil outlet channel 12. At this time, the switch valve 40 closes the oil return channel 13 and disconnects the oil outlet channel 12 and the second outlet 112 .

As a preferred or optional embodiment, the oil outlet valve 50 includes an oil outlet steel ball 52 connected to the jack body 10 through an oil outlet pressure spring 51. When the oil outlet channel 12 returns oil, the returning oil pushes The oil outlet steel ball 52 blocks the connection between the oil outlet channel 12 and the first outlet 111. At this time, the oil outlet channel 12 is disconnected from the first outlet 111; when oil is fed, the oil flowing out of the first outlet 111 is pushed out. The oil steel ball 52 enters the oil cylinder assembly through the oil outlet channel 12, and the above-mentioned joint is opened at this time; the oil outlet valve 50 of such a structure has a reasonable and compact structure, which ensures the reliability of work.

Further, in order to ensure the reliability of the operation of the on-off valve 40 and the compactness of the overall jack structure, especially the structural compactness of the on-off valve 40 integrated in the jack body 10, The hollow switch casing 41, the switch valve core 42, which is axially movably installed in the middle of the switch casing 41 and partially protrudes out of the jack body 10, and the switch wrench 43 connected to the end of the switch valve core 42 away from the jack body 10, are in the switch. A torsion spring 44 is arranged between the wrench 43 and the jack body 10 , and a switch channel 411 for connecting the oil return channel 13 and the second outlet 112 is arranged in the middle of the switch casing 41 , and the switch wrench 43 can drive the switch spool 42 to displace and open Or turn off the switch channel 411.

During the lifting operation, the switch wrench 43 is controlled to rotate and drive the switch spool 42 to move linearly so that the switch channel 411 is closed. At this time, the oil return channel 13 and the second outlet 112 are disconnected, that is, the oil outlet channel 12 and the second outlet 112 are disconnected open, the switch valve 40 is in the closed state, and the oil enters the oil cylinder assembly from the oil tank through the first outlet 111 and the oil outlet channel 12 to complete the lifting of the platform; during the descending operation, open the switch channel 411, so that the oil outlet channel 12, return The oil channel 13 and the second outlet 112 are connected. At this time, the oil returning to the oil pushes the oil outlet valve 50 to disconnect the oil outlet channel 12 and the first outlet 111 (ie, block the first outlet 111), and the oil flows through the oil outlet. The channel 12 , the oil return channel 13 , the switch channel 411 , and the second outlet 112 are recovered into the oil tank from the oil inlet 11 to complete the descending of the platform.

The setting of the above-mentioned torsion spring 44 can well control the rotation amplitude of the switch, and can complete the switch amount of the switch valve 40, thereby reliably and accurately controlling the oil return flow, that is, controlling the descending displacement of the platform, and ensuring the smoothness of the descending process of the platform. Avoid the collision caused by rapid descent or sudden drop.

Further, a switch steel ball 45 is provided at the butt joint of the switch channel 411 and the oil return channel 13 , and the switch wrench 43 can be manipulated to drive the switch valve core 42 to axially displace. At this time, the switch valve core 42 extends into one end of the switch casing 41 The ends can press the switch steel ball 45 against the above-mentioned butt joint or disengage from the switch steel ball 45 .

During the lifting operation, the switch spool 42 presses the switch steel ball 45 against the above-mentioned butt joint. At this time, the switch channel 411 is in a closed state, and the oil return channel 13 and the second outlet 112 are disconnected; during the lowering operation, the switch spool 42 and The switch steel ball 45 is out of contact. At this time, the switch steel ball 45 is in an active state, the oil return channel 13, the switch channel 411 and the second outlet 112 are connected, and the returning oil pushes the oil outlet steel ball 52 (oil outlet valve 50) to close. At the first outlet 111 , the oil is intelligently returned to the fuel tank through the oil outlet 12 , the oil return channel 13 , the switch channel 411 , and the second outlet 112 .

In order to ensure the reliability and stability of the overall jack structure layout, it is preferable that the switch casing 41 is further limited on the jack body 10 through the set screw 46, and the set screw 46 there is perpendicular to the switch casing 41; The hexagonal screw is fixed on the valve core, and the inner hexagonal screw there is located outside the jack body 10 .

In order to ensure the reliability and stability of the jack's work and overcome the overload situation, preferably a third outlet 113 is provided on the oil inlet 11, and an oil inlet channel 14, which is connected to the first outlet 111 is also provided on the jack body 10. The overload protection channel 15 and the connection port 16 connected with the third outlet 113, the connection port 16 communicates with the oil inlet channel 14, the oil outlet channel 12 and the overload protection channel 15 respectively, and the connection port 16 is connected with the oil inlet channel 14. An oil inlet valve 60 is arranged at the jack body, the oil outlet valve 50 is arranged at the butt joint of the connection port 16 and the oil outlet passage 12, and a safety valve 70 adapted to the overload protection passage 15 is arranged on the jack body 10 and the safety valve 70 is a one-way safety valve 70, the safety valve 70 is used to open and close the overload protection channel 15, the oil inlet valve 60 and the oil outlet valve 50 are opened when the oil inlet channel 14 enters the oil, and the safety valve 70 is closed at this time. The protection channel 15, the third outlet 113 and the connection port 16 are disconnected. When overloaded, the oil flows back and closes the oil outlet valve 50. At this time, the oil in the oil inlet channel 14 passes through the connection port 16 and pushes open the safety valve 70. Overload protection The channel 15 is opened, and the oil flows back to the oil tank through the overload protection channel 15 and the third outlet 113 .

The above-mentioned safety valve 70 is also integrated on the jack body 10, which reduces the external structure and ensures the stability of the overall jack operation. During operation (when lifting), the oil flows in from the oil inlet 11 and passes through the first outlet. 111. The oil inlet channel 14 and the oil outlet steel ball 52 of the oil outlet valve 50 are pushed up, and the oil flows into the oil outlet channel 12 and enters the oil cylinder assembly; when the heavy objects on the platform are overloaded, the oil liquid will flow back into the oil cylinder, After filling the oil outlet channel 12 with liquid, push the oil outlet steel ball 52 of the oil outlet valve 50 to block the corresponding butt joint. At this time, the oil outlet channel 12 no longer receives oil, and the oil flowing out of the oil inlet channel 14 can only be discharged from the overload protection channel. 15 enters, push open the safety valve 70 at the corresponding docking point and open the overload protection channel 15, the oil flows back to the fuel tank from the overload protection channel 15, the third outlet 113, and the oil inlet 11 to protect the vehicle from overload.

Preferably, in order to ensure smooth oil discharge and oil return, avoid jamming, and ensure work efficiency and reliability, the second outlet 112 and the third outlet 113 are arranged on both sides of the first outlet 111 and are located at the oil inlet. In the middle position of 11, the first outlet 111 is arranged at the lower position of the oil inlet 11, the oil inlet channel 14 is arranged vertically, the oil outlet channel 12 is arranged horizontally, and the overload protection channel 15 is arranged vertically, so The connection port 16 is located below the first outlet 111; the vertical overload protection channel 15 is more conducive to normal lifting operations, the oil will not flow back into the overload protection channel 15, and the safety valve 70 is only opened when overloaded.

Further, an oil discharge port 161 and a corresponding oil discharge valve 80 are provided at the lower position of the connection port 16, that is, an oil discharge port 161 is left at the bottom of the jack, and only the oil discharge valve 80 at the bottom (preferably threaded connection) is loosened. On the jack body 10, it is only necessary to unscrew the oil unloading valve 80 when loosening, so that the internal oil can flow out, which is convenient for cleaning the entire inside of the jack.

In order to ensure the reliability of the connection between the oil inlet channel 14 and the connection port 16 and ensure the effect of the one-way valve, the oil inlet valve 60 includes an oil inlet steel ball 62 connected to the jack body 10 through an oil inlet pressure spring 61. The ball 62 is blocked at the joint of the oil inlet passage 14 and the connection port 16 by the elastic force of the oil inlet pressure spring 61. When the oil inlet passage 14 enters oil, the oil pushes the oil inlet steel ball 62 and connects to the oil inlet passage 14. And the connection port 16, the elastic force F1 (maximum elastic restoring force) of the oil inlet pressure spring 61 is greater than the elastic force F2 of the oil outlet spring. Since F1>F2, when lifting, the oil enters the oil outlet channel 12 from the oil inlet channel 14 and flows into Cylinder assembly.

In order to ensure the rationality of the setting of the overload protection structure and the reliable operation of the overload protection, it is preferable that the safety valve 70 includes an overload steel ball 71 and a pressing mechanism for pressing the overload steel ball 71 against the connection between the overload protection channel 15 and the connection port 16 . , the pressing mechanism includes an overload compression spring 72 connected to the overload steel ball 71. When overloaded, the oil in the oil inlet channel 14 passes through the connection port 16 and pushes the overload steel ball 71 away, and the overload protection channel 15 is opened.

In this case, it is preferred that the overload steel ball 71 is located in the overload protection channel 15 , the oil inlet steel ball 62 is located in the connection port 16 , the oil outlet steel ball 52 is located in the oil outlet channel 12 , and the switch steel ball 45 is located in the switch channel 411 .

Further, the above-mentioned pressing mechanism also includes a sheath 73 installed on the outer side of the jack body 10, an adjustment screw 74 placed in the sheath 73 and inserted on the jack body 10, and the overload compression spring 72 is connected to the adjustment screw. 74 and the overload steel ball 71.

Further, in order to ensure the compact layout of the overall jack and the close cooperation between the various structures to form a tight and compact jack structure, one end of the above-mentioned torsion spring 44 is fixed on the switch valve core 42 by a hexagon socket screw, and the other end leans against the spool 42. on the sheath 73 of the safety valve 70 .

A sealing ring 75 is arranged between the outer wall of the adjusting screw 74 and the jack body 10. In order to prevent the sealing ring 75 from being included in the stroke of the thread of the adjusting screw 74 and causing the sealing ring 75 to contact the thread and causing damage to the sealing ring 75, the safety valve 70 After multiple adjustments, the sealing effect will be affected, causing the pressure of the safety valve 70 to maintain pressure, which may cause danger; in this case, a further improvement is made, and the adjustment thread position is moved down to avoid contact with the sealing ring 75, that is, the sealing ring 75 in this case. Set above the threaded position of the adjusting screw 74 .

Preferably, the jack transmits the hydraulic oil to the oil cylinder through the oil pipe to complete the lifting process, and the oil cylinder assembly is the execution unit of this case. The oil pipe joint 90 partially extends into the oil outlet channel 12 and is connected with the oil outlet pressure spring 51 .

To sum up, this hydraulic jack is a small and lightweight jack, which integrates important components such as on-off valve 40, safety valve 70, oil discharge valve 80, etc. Although the sparrow is small, it has all the internal organs, eliminating the need for other external mechanical structures. device.

The oil inflow process is as follows: through manual control or stepping on the foot lever 30, the oil in the oil tank flows into the jack from the oil inlet 11 due to the principle of atmospheric pressure, and there are three holes at the inlet (that is, the three outlets of the oil inlet 11). ), since the switch valve core 42 of the second outlet 112 is not opened, the overload steel ball 71 corresponding to the third outlet 113 is held up by the compression spring (similar to a one-way valve), so the oil can only enter the oil inlet channel from the first outlet 111 14; As the oil pressure increases, the oil ball 62 is jacked into the oil. Since the above F1>F2, the oil flows into the oil outlet channel 12 and enters the oil cylinder to complete the lifting of the platform.

The oil return process is as follows: when the switch valve core 42 is opened, the oil outlet steel ball 52 at the oil outlet channel 12 is held up by the compression spring (similar to a one-way valve) due to the backflow of the heavy object and the oil itself. Therefore, The descending process of the platform can only be completed by flowing back to the oil tank from the oil return channel 13 , the switch channel 411 and the second outlet 112 .

The overload situation is as follows: the oil flows in from the oil inlet 11 and flows into the oil outlet 12 through the oil inlet channel 14. However, due to the overload of heavy objects, the oil flows into the oil cylinder and then flows back. When the oil fills the oil outlet channel 12, it will no longer be Inflow, it can only flow back to the fuel tank from the overload protection channel 15 through the safety valve 70 to protect the entire vehicle from overload.

The specific embodiments described herein are merely illustrative of the spirit of the invention. Those skilled in the art to which the present invention pertains can make various modifications or additions to the described specific embodiments or substitute in similar manners, but will not deviate from the spirit of the present invention or go beyond the definitions of the appended claims range.

Claims (10)

1. An oil hydraulic jack, comprising: tank; Cylinder assemblies for lifting or lowering operations; It is characterized by: The jack body is provided with an oil inlet with a first outlet and a second outlet, an oil outlet channel connecting the oil cylinder assembly and the first outlet, and an oil return channel connecting the oil outlet channel and the second outlet; an oil pump assembly, which is arranged on the jack body and includes a pump core; The foot lever is hinged on the jack body and connected with the pump core. The displacement of the pump core can be driven by stepping on the foot lever manually or by foot, and the oil pump assembly is driven to introduce the oil in the oil tank into the oil inlet by using the principle of atmospheric pressure; The switch valve is integrated in the jack body and is adapted to the oil return passage. The switch valve is used to open and close the oil return passage. When the oil return passage is closed, the oil outlet passage is disconnected from the second outlet and is connected to the first outlet. An outlet is connected, and when the oil return channel is opened, the oil outlet channel is disconnected from the first outlet and connected to the second outlet. 2. A hydraulic jack according to claim 1, characterized in that: an oil outlet valve is provided at the butt joint of the oil outlet channel and the first outlet, and when the oil outlet channel returns oil, the backflow oil pushes The oil outlet valve is made to block the above-mentioned butt joint, and the oil outlet channel is disconnected from the first outlet at this time. 3 . The hydraulic jack according to claim 2 , wherein the oil outlet valve comprises an oil outlet steel ball connected to the jack body through an oil outlet pressure spring, and when the oil is returned to the oil outlet channel. 4 . , the returning oil pushes the oil outlet steel ball and blocks the connection between the oil outlet channel and the first outlet, and at this time, the oil outlet channel is disconnected from the first outlet. 4 . The hydraulic jack according to claim 1 , wherein the on-off valve comprises a hollow switch jacket inserted in the jack body, axially movably mounted in the middle of the switch jacket and partially extended. 5 . The switch spool out of the jack body, the switch wrench connected to the end of the switch spool away from the jack body, a torsion spring is arranged between the switch wrench and the jack body, and a middle part of the switch jacket is provided for connecting the oil return channel and the second For the switch channel at the outlet, manipulating the switch wrench can drive the switch valve core to move and open or close the switch channel. 5. A hydraulic jack according to claim 4, characterized in that: a switch steel ball is provided at the butt joint of the switch channel and the oil return channel, and the switch wrench can be manipulated to drive the switch valve core to move axially. One end of the switch valve core extending into the switch casing can press the switch steel ball against the above-mentioned butt joint or disengage from the switch steel ball. 6. A kind of hydraulic jack according to claim 2 is characterized in that: a third outlet is also provided on the oil inlet, and an oil inlet channel connected with the first outlet is also provided on the jack body, and a third outlet is also provided on the jack body. The overload protection channel and the connection port are connected with the three outlets. The connection port is respectively communicated with the oil inlet channel, the oil outlet channel and the overload protection channel. The valve is arranged at the connection between the connection port and the oil outlet channel, and the jack body is provided with a safety valve adapted to the overload protection channel, and the safety valve is a one-way safety valve. The safety valve is used to open and close the overload protection channel. , Open the oil inlet valve and the oil outlet valve when the oil enters the oil inlet channel. At this time, the safety valve closes the overload protection channel, and the third outlet is disconnected from the connection port. When the oil is overloaded, the oil flows back and closes the oil outlet valve. The oil in the oil inlet channel passes through the connection port and pushes the safety valve open, the overload protection channel is opened, and the oil flows back to the oil tank through the overload protection channel and the third outlet. 7 . The hydraulic jack according to claim 6 , wherein the second outlet and the third outlet are arranged on both sides of the first outlet, and the two are located in the middle of the oil inlet, and the first outlet is located in the middle of the oil inlet. 8 . The outlet is arranged at the lower position of the oil inlet, the oil inlet channel is arranged vertically, the oil outlet channel is arranged horizontally, the overload protection channel is arranged vertically, and the connection port is located below the first outlet. 8 . The hydraulic jack according to claim 6 , wherein the oil inlet valve comprises an oil inlet steel ball connected to the jack body through an oil inlet pressure spring, and the oil inlet steel ball passes through the inlet valve. 9 . The elastic force of the oil pressure spring is blocked at the butt joint of the oil inlet channel and the connection port. When the oil inlet channel enters the oil, the oil pushes the oil inlet steel ball and connects the oil inlet channel and the connection port. 9 . The hydraulic jack according to claim 6 , wherein the safety valve comprises an overload steel ball, a pressing mechanism for pressing the overload steel ball on the butt joint of the overload protection channel and the connection port. 10 . , the pressing mechanism includes an overload compression spring connected with the overload steel ball. When overloaded, the oil in the oil inlet channel passes through the connection port and pushes the overload steel ball away, and the overload protection channel is opened. 10. The hydraulic jack according to any one of claims 1 to 9, wherein an oil pipe joint for connecting the oil outlet channel and the oil cylinder assembly is detachably installed on the jack body, and the oil pipe joint is partially It extends into the oil outlet channel and connects with the oil outlet pressure spring.

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