Retarded descending device for no-load and heavy-load jack
By installing a base core and compression spring structure at the bottom of the large cylinder of the hydraulic jack, and adjusting the oil drain gap and notch, a slow descent under heavy load and a rapid return under light load can be achieved, solving the problem of mismatched descent speed of the hydraulic jack and improving work efficiency and equipment safety.
Patent Information
- Application Number
- CN202423293804.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-30
- Publication Date
- 2025-12-26
- Estimated Expiration
- 2034-12-30
AI Technical Summary
When lifting heavy objects, especially under heavy loads, the falling speed of existing hydraulic jacks is directly proportional to the weight, resulting in a large impact force. Under light loads, the falling speed is slow, which affects work efficiency.
A base core and compression spring structure are installed at the bottom of the large oil cylinder. By adjusting the oil drain gap and oil drain notch, the hydraulic oil draining speed can be controlled. Combined with the design of a check valve and return oil pipeline, it can achieve slow descent under heavy load and fast return under light load.
Reduce impact under heavy loads to improve work efficiency, and enable rapid return under light loads to avoid damage to machine parts and improve overall work efficiency.
Smart Images
Figure CN223722673U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to hoisting tools, in particular to a slow speed descending device for the no-load and heavy load of a jack. BACKGROUND
[0002] Hydraulic jacks are commonly used hoisting tools, such as in automobile repair work. The working principle of the hydraulic jack is that the wrench is pulled up to drive the small piston upward, and the oil in the oil tank is sucked into the lower part of the small piston through the oil pipe and the one-way valve. When the wrench is pressed downward, the small piston is driven downward, and the oil tank and the oil passage below the small piston are blocked by the one-way valve. The oil below the small piston is pressed into the lower part of the large piston through the internal oil passage and the one-way valve. Due to the lever effect, the pressure in the lower part of the small piston increases, and the area of the large piston is larger than that of the small piston. The oil pressure generated by hand is squeezed into the large piston. According to the Pascal principle, the area ratio of the small piston to the large piston is the same as the pressure ratio (the pressure in the system is equal). In this way, the force on the hand is transmitted to the small piston through the wrench, and the area of the large piston is larger than that of the small piston. The force from the small piston to the large piston is increased. When working, the small piston of the hand oil pump is continuously pressed into the large oil cylinder by reciprocating the wrench up and down. Due to the continuous increase of the pressure oil in the large oil cylinder, the large piston and the weight above the large piston are forced to move upward (lift) together, thereby achieving the effect of lifting. When the return oil valve is opened, the high-pressure oil in the large oil cylinder flows back to the oil tank, so that the weight and the large piston fall together. However, when falling, the falling speed is proportional to the weight of the weight, and when the lifted weight is large, it will suddenly fall at the moment when the return oil valve is opened, and the huge impact force will cause damage to the machine parts. When the lifted weight is small (light) or no load, the downward thrust of the large oil cylinder is small when the return oil valve is opened, and the large oil cylinder will slowly descend, affecting the speed of the return stroke and reducing the working efficiency. CONTENT OF THE UTILITY MODEL
[0003] The utility model aims at providing a hydraulic system slow speed descending device which has the advantages of simple structure, convenient use and low manufacturing cost, and can slow down the return stroke when the lifted weight is heavy and can quickly return when the lifted weight is light.
[0004] In order to solve the above problems, the technical scheme of the utility model: it includes a small oil cylinder, a large oil cylinder and an oil tank. The small oil cylinder is communicated with the oil tank through a one-way oil inlet valve. A one-way oil outlet valve is connected between the small oil cylinder and the large oil cylinder. A piston rod for lifting the weight is installed in the large oil cylinder. The bottom of the large oil cylinder is connected with a base core. The base core is installed in the oil cylinder base. The bottom of the base core has an upwardly concave pit. A compression spring is installed between the pit and the oil cylinder base. A drain gap A is provided between the base core and the oil cylinder base. A plurality of drain notches are provided around the bottom of the base core. A return oil pipeline is provided on the large oil cylinder and communicated with the pit on the base core. A return valve is provided on the return oil pipeline.
[0005] The oil drain gap A is 0.1 to 0.3 mm.
[0006] The working principle of the slow-descending device for a jack under no-load and heavy-load conditions manufactured according to the above scheme is as follows:
[0007] 1. Light load descent, such as Figure 1 As shown: When there is no object or the object is light on the piston rod, when the return valve is opened, the oil in the large oil cylinder enters the pit through the return oil line. At the same time, the pressure of the object on the compression spring is small, and the compression spring lifts the base core, increasing the gap between the base core and the oil cylinder base. The hydraulic oil is quickly drained through the drain notch and the gap between the base core and the oil cylinder base, and then quickly drained back to the oil tank through drain gap A. The piston rod descends rapidly, achieving the effect of the piston rod quickly descending and returning to its position when unloaded, thus improving the working efficiency of the return oil.
[0008] 2. Heavy load descent, such as Figure 2 As shown: When a heavy object is placed on the piston rod, when the return valve is opened, the oil in the large oil cylinder enters the pit through the return line. At the same time, the pressure of the object on the compression spring is relatively large. The compression spring only slightly lifts the base core. The gap between the base core and the oil cylinder base is small. The hydraulic oil slowly drains through the small drain gap and the gap between the base core and the oil cylinder base (this gap may not exist when the object is heavy enough). The drained hydraulic oil returns to the oil tank through drain gap A. The piston rod also slowly descends, achieving the effect of slow descent under heavy load, so as to reduce the impact force of the heavy object on the hydraulic device.
[0009] When a heavy object is supported on the large hydraulic cylinder, the oil drains only through a small drain notch and a small gap between the base core and the cylinder base, thus slowing down the draining speed and causing the heavy object and cylinder to descend slowly, reducing the impact force during descent. If a lighter object is supported on the large hydraulic cylinder, the base core is still supported by the compression spring or descends slightly. This increases the drain notch and the gap between the base core and the cylinder base, increasing the draining speed and improving efficiency. Due to its lower weight, even a faster descent will not damage the machine components. Attached Figure Description
[0010] Figure 1 This is a schematic diagram of the working principle of the jack lowering device when it is unloaded (lightly loaded).
[0011] Figure 2 This is a schematic diagram of the working principle of the jack lowering device under heavy load.
[0012] In the diagram: 1. Large hydraulic cylinder; 2. Small hydraulic cylinder; 3. Oil tank; 4. One-way inlet valve; 5. One-way outlet valve; 6. Piston rod; 7. Base core; 8. Hydraulic cylinder base; 9. Pit; 10. Compression spring; 11. Oil drain gap; 12. Oil drain notch; 13. Return oil pipeline; 14. Return oil valve. DETAILED DESCRIPTION
[0013] The utility model will be further described below in combination with the drawings and specific embodiments.
[0014] Figure 1 、 Figure 2 It is a kind of jack empty load and heavy load's structure diagram of slow speed descending device.From the figure, it includes for the small oil cylinder 2 of big oil cylinder 1 pumping oil, big oil cylinder 1, oil tank 3, small oil cylinder 2 is communicated with oil tank 3 by one-way oil inlet valve 4, small oil cylinder 2 is connected with one-way oil outlet valve 5 between big oil cylinder 1, big oil cylinder 1 is installed with the piston rod 6 of lifting heavy object in, the bottom of big oil cylinder 1 is connected with the base core 7, the base core 7 is installed in the cylinder base 8, wherein the bottom of base core 7 has a upward concave pit 9, pit 9 is installed with compression spring 10 between cylinder base 8, the oil discharge gap 11 between base core 7 and cylinder base 8 is equipped, the size A of oil discharge gap 11 is 0.1 to 0.3 millimeter, a plurality of oil discharge notches 12 are equipped on the periphery of the bottom of base core 7, oil return line 13 is equipped on big oil cylinder 1 and is communicated with the pit 9 on base core 7, oil return valve 14 is equipped on oil return line 13.
Claims
1. A slow-descent device for a jack under no-load and heavy-load conditions, comprising a small hydraulic cylinder, a large hydraulic cylinder, and an oil tank; the small hydraulic cylinder is connected to the oil tank via a one-way inlet valve; a one-way outlet valve connects the small hydraulic cylinder and the large hydraulic cylinder; and a piston rod for lifting the load is installed inside the large hydraulic cylinder. The device is characterized by: The bottom of the large oil cylinder is connected with a base core, the base core is installed in the oil cylinder base, the bottom of the base core has an upwardly concave pit, a compression spring is installed between the pit and the oil cylinder base, an oil leakage gap A is arranged between the base core and the oil cylinder base, the periphery of the bottom of the base core is provided with a plurality of oil leakage notches, an oil return pipeline is arranged on the large oil cylinder and communicates with the pit on the base core, and an oil return valve is arranged on the oil return pipeline.
2. A device for slow descent of a load under the action of gravity from a j ack according to claim 1, characterised in that The oil leakage gap A is 0.1-0.3 mm.