Scissor jack

Abstract

The invention relates to the technical field of hoisting, in particular to a scissor jack which comprises a tray arranged at the top of a scissor arm and used for being connected with an automobile, a base is arranged at the bottom of the scissor arm, an anti-toppling mechanism is arranged below the base and comprises a seat frame and a perforated plate, and a main shaft is rotationally connected to the seat frame. According to the scissor jack provided by the invention, on the premise that the placement stability of the scissor jack is maintained, the step of finding a steel cushion plate or putting a wood block into the bottom of the scissor jack is omitted, and the scissor jack is helpful to jack up an automobile to replace tires.

Description

Technical Field

[0001] The invention belongs to the technical field of lifting, and in particular relates to a scissor jack. Background Art

[0002] As a vehicle-mounted lifting tool, a scissor jack operates on the principle that a screw drive mechanism converts the rotational motion of a screw into angular changes in the scissor arms, thereby achieving vertical lifting capabilities for operations such as vehicle lifting and tire changing. However, in practical applications on complex terrain (such as soft ground and slopes), existing technical solutions have significant drawbacks, which are directly related to the technical improvements of the present invention: 1. Insufficient stability and complicated operation when used on soft ground In soft ground environments (such as mud and sand), traditional scissor jacks rely on external pads (such as steel plates and wood blocks) to enhance support stability. However, this solution has the following problems: Poor bedding adaptability and low operational efficiency: It is necessary to temporarily find suitable bedding on site, which is time-consuming, especially in field environments. In addition, ordinary materials (such as wooden pads) are prone to support failure due to insufficient strength. Stacked cushions are prone to displacement: When multiple layers of cushions are stacked, there is a lack of fixed structure between the layers, which can easily lead to lateral slippage due to uneven force (for example, when stacking more than two layers of wooden boards, the middle layer of wooden boards may shift due to excessive local pressure), which in turn causes the jack to tilt.

[0003] The above defects result in the existing technology requiring additional operation steps and failing to ensure stability under soft ground. The present invention achieves fixation by directly inserting the gripping spikes into the ground without the need for padding, significantly improving operational convenience and support reliability.

[0004] 2. Single support structure leads to insufficient contact area The support structure of existing scissor jacks mainly relies on the contact between the base plane and the pad, which has the following limitations: Low stability of one-way support: Support is provided only through plane contact, without forming vertical and horizontal two-way constraints. When the load-bearing object shakes slightly, it is easy to topple due to the small contact area and insufficient friction. Weak ability to resist lateral loads: When facing lateral forces (such as the torque generated by the shift of the center of gravity during vehicle jacking), a single support surface cannot effectively distribute the load, resulting in a decrease in overall stability.

[0005] 3. Lack of adaptive support and self-locking mechanism in slope scenarios In sloped environments (such as mountain roads and garage slopes), traditional scissor jacks have the following safety hazards: The base plane is difficult to fit naturally with the slope, resulting in an angle between the top tray and the vehicle support point, which makes it easy to slide due to lateral force when subjected to force. Summary of the Invention

[0006] In view of the deficiencies in the prior art, an object of the present invention is to provide a scissor jack.

[0007] To achieve the aforementioned object of the invention, the technical solutions adopted by the present invention include: A tray is provided at the top of the scissor-type arm for connecting to the car. A base is provided at the bottom of the scissor-type arm, and an anti-dumping mechanism is provided below the base. The anti-dumping mechanism includes a seat frame and a porous plate. A main shaft is rotatably connected to the seat frame, and the main shaft is fixedly connected to the base. A plurality of gripping spikes are provided between the seat frame and the porous plate. A driving member is provided on the top of the plurality of gripping spikes for driving them to move. When the seat frame is rotated to a position perpendicular to the base, the gripping spikes are driven by the driving member to extend to the outside of the porous plate and insert into the soft soil. In the present invention, the gripping spikes are extended and inserted into the soft ground by rotating the seat frame. The gripping spikes are deeply embedded in the soil, providing stability for the connection between the scissor jack and the soft ground. While maintaining the placement stability of the scissor jack, the step of finding a steel plate or wooden block to place under the bottom of the scissor jack is eliminated, which facilitates the operation of jacking up a car with the scissor jack to change a tire.

[0008] An auxiliary support mechanism is provided in the scissor-type arm, and the auxiliary support mechanism includes two side support rods rotatably connected to the scissor-type arm. A locking part is provided on one side of the side support rod. When the seat frame is rotated to a vertical state with the base, the anti-dumping mechanism releases the movement restriction of the auxiliary support mechanism through the locking part, so that the two side support rods are rotated by gravity and inserted into the soft soil.

[0009] In the present invention, the rotation of the seat frame triggers the two side support rods to rotate under the action of gravity and insert into the soft soil, forming a vertical and horizontal two-way ground support between the scissor jack and the soft soil, which not only expands the contact area between the scissor jack and the soft soil, but also further improves the placement stability of the scissor jack, thereby preventing the scissor jack from shaking and tilting during the lifting process.

[0010] Preferably, the anti-dumping mechanism is provided with a slope self-locking component, which includes a blocking plate slidably arranged in the porous plate, and the blocking plate is used to block the holes of the porous plate. The slope self-locking component also includes a lifting screw, and the lifting screw adjusts the angle between the seat frame and the porous plate by pushing two of the gripping nails to move.

[0011] In the present invention, when the scissor jack is used to lift a car on a slope, the porous plate is made to fit with the inclined surface of the slope, and the lifting screw pushes the gripping nails to move against the blocking plate to cause the porous plate and the seat frame to rotate relative to each other, so that the supporting surface fits with the load-bearing object and the lateral force is balanced. The self-locking effect of the inclined surface is used to prevent the scissor jack from sliding, so that the scissor jack can easily lift the car even on a slope, making it convenient to change the tire of the car.

[0012] Preferably, the driving member includes multiple traction ropes, and one end of the main shaft extending into the seat frame is wound and connected with the multiple traction ropes, each of the traction ropes has multiple rope heads, and the multiple rope heads are connected to the gripping nails at corresponding positions, and each of the gripping nails is provided with a nail tube, and the nail tube is fixedly connected to the seat frame, and a connecting ring is fixedly connected to the inside of each nail tube, and a reset spring is fixedly connected to the bottom of the connecting ring, and the reset spring is connected to the gripping nail at the corresponding position.

[0013] Preferably, the locking component includes two locking plates respectively fixedly connected to the two side support rods, each of the locking plates is inserted with a positioning fork, each of the positioning forks is fixedly connected with a short-circuit shaft, each of the short-circuit shafts is rotatably connected to the scissor arm, each of the short-circuit shafts is fixedly connected with a torsion spring, and the torsion spring is fixedly connected to the scissor arm.

[0014] Preferably, one end of the main shaft extending into the base is rotatably connected to a turntable, the turntable is fixedly connected to the seat frame, and the top of the turntable is fixedly connected to two unlocking rods for contacting the positioning fork.

[0015] Preferably, handles are provided on both sides of the blocking plate, and sliding openings for the handles to slide are provided in the porous plate.

[0016] Preferably, two nail barrels close to the lifting screws are provided with lifting openings, and fan-shaped rods are slidably connected in the two lifting openings. In the nail barrel lifting openings, the two fan-shaped rods are vertically stacked, and an internal threaded sleeve is fixedly connected in the seat frame. The lifting screw is threadedly connected to the internal threaded sleeve, and one end of the lifting screw extends to the inside of the seat frame and is rotatably connected to a pressure plate, and the pressure plate is arranged above the two fan-shaped rods.

[0017] Compared with the prior art, the advantages of the present invention include: (1) The present invention provides a scissor jack that can extend its gripping spikes and insert them into soft soil by rotating its seat frame, so that the gripping spikes are embedded deep in the soil, thereby providing stability for the connection between the scissor jack and the soft soil. While maintaining the placement stability of the scissor jack, the step of finding a steel plate or a wooden block to pad the bottom of the scissor jack is eliminated, thereby facilitating the scissor jack to lift a car for tire replacement. (2) The present invention provides a scissor jack, which can trigger the rotation of the seat frame to rotate the two side support rods under the action of gravity and insert them into the soft ground, forming a vertical and horizontal two-way ground support between the scissor jack and the soft ground. This not only expands the contact area between the scissor jack and the soft ground, but also further improves the placement stability of the scissor jack, thereby preventing the scissor jack from shaking and tilting during the lifting process; (3) The present invention provides a scissor jack that can make the porous plate fit with the slope of the slope. The lifting screw pushes the gripping nails to move against the blocking plate to make the porous plate and the seat frame rotate relative to each other, so that the supporting surface fits with the load-bearing object and balances the lateral force. The self-locking effect of the slope is used to prevent the scissor jack from sliding, so that the scissor jack can easily lift the car even on the slope, making it convenient to change the tire of the car. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments recorded in this application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0019] Figure 1 It is an overall schematic diagram of a scissor jack in the present invention; Figure 2 This is a schematic diagram of the explosion effect of the base structure in the present invention; Figure 3 Schematic diagram of the connection structure of the side support rod in the present invention; Figure 4 Schematic diagram of the transmission structure of the side support rod and the anti-dumping mechanism in the present invention; Figure 5 for Figure 2 A magnified view of the structure at point A; Figure 6 This is a schematic diagram of the connection structure of the gripping spikes in the present invention; Figure 7 Schematic diagram of the structure of the positioning member in the present invention; Figure 8 It is a structural schematic diagram of the tray in the present invention. DETAILED DESCRIPTION

[0020] In view of the deficiencies in the prior art, the inventors of this case have proposed the technical solution of the present invention after long-term research and extensive practice. The following will further explain the technical solution, its implementation process and principles, etc. in conjunction with the drawings in the embodiments of this application and specific implementation cases.

[0021] It should be noted that the embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be understood as limiting the present invention. The embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, the present invention covers any substitution, modification, equivalent method and scheme made within the spirit, principle and scope of the present invention defined by the claims. All other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0022] In the description of this application, "first", "second", "third" and similar words do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, "a" or "an" and other similar words do not indicate a quantity limitation, but rather indicate the existence of at least one. "Include" or "comprising" and other similar words mean that the elements or objects appearing before "include" or "comprising" include the elements or objects listed after "include" or "comprising" and their equivalents, and do not exclude other elements or objects. "Connected" or "connected" and other similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect.

[0023] In the description of this application, the terms "center," "up," "down," "front," "back," "left," "right," "vertical," "horizontal," "top," "bottom," "inside," "outside," and the like, indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings and are intended only to facilitate the description of this application and simplify the description. They are not intended to indicate or imply that the devices or components referred to must have a specific direction, be constructed, or operate in a specific direction. Therefore, they should not be construed as limitations on this application. Furthermore, when positional terms such as "both sides," "outside," "upper," and "lower" are used, they should be understood to be used solely to facilitate understanding and description, taking into account that the structure may be oriented in other directions.

[0024] In the description of this application, unless otherwise clearly specified and limited, the technical or scientific terms used should have the usual meanings understood by persons with ordinary skills in the field to which this application belongs. Terms such as "install", "connect", and "connect" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, a conflicting connection, or an integrated connection. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0025] The embodiments of the present invention are intended to introduce and illustrate the structural composition of a scissor jack and the coordination relationship between the various components. Unless otherwise specified, the dimensions, materials, and manufacturing processes of the various components of the scissor jack in the embodiments of the present invention can be selected according to specific circumstances and are not specifically limited or described herein.

[0026] Furthermore, in order to provide the public with a better understanding of the present invention, some specific details are described in detail in the following detailed description of the present invention, but those skilled in the art can fully understand the present invention without the description of these details. Example 1

[0027] See also Figure 1 、 Figure 2 and Figure 8 This embodiment discloses a scissor jack, including a scissor arm 2.

[0028] Specifically, the scissor arm 2 includes two top rods 21 and two bottom rods 22, each top rod 21 is rotatably connected to the bottom rod 22 at the corresponding position, a lifting screw 23 is rotatably connected to the connection between one of the top rods 21 and the bottom rod 22, and a nut 24 is fixedly connected to the connection between the other top rod 21 and the bottom rod 22, and the nut 24 is threadedly connected to the lifting screw 23. The two top rods 21 are jointly connected to a pallet 1.

[0029] Furthermore, the tray 1 includes a base 14, two top rods 21 rotatably connected to the base 14, a rotating seat 16 rotatably connected to the middle of the top of the base 14, a bracket 11 rotatably connected to the top of the rotating seat 16, a docking groove 15 for connecting to the car is provided in the middle of the bracket 11, and angle adjustment rods 12 are rotatably connected to both sides of the bottom of the bracket 11, and the angle adjustment rods 12 are plugged into the base 14. Two prisms 13 are plugged into both sides of the base 14, and a plurality of prism holes are provided in the angle adjustment rods 12 to match the prisms 13. It should be noted that when the scissor jack is used on a slope, the angle adjustment of the docking groove 15 can be completed by pulling out the two prisms 13 from the prism holes, rotating the bracket 11 so that the docking groove 15 is parallel to the steel beam used for jacking at the bottom of the car, and then inserting the two prisms 13 into the prism holes at the corresponding positions of the angle adjustment rod 12, so that the pallet 1 can always maintain an angle parallel to the steel beam used for jacking at the bottom of the car, making the connection between the pallet 1 and the bottom of the car more stable.

[0030] See also Figure 1 、 Figure 2 、 Figure 3 、 Figure 4 、 Figure 5 、 Figure 6 and Figure 7The present embodiment discloses a scissor jack, including a base 49, two bottom rods 22 are rotatably connected to the base 49, an anti-dumping mechanism 3 is provided below the base 49, the anti-dumping mechanism 3 includes a seat frame 31 and a porous plate 34, a main shaft 38 is rotatably connected to the seat frame 31, the main shaft 38 is fixedly connected to the base 49, a plurality of gripping nails 33 are provided between the seat frame 31 and the porous plate 34, and a driving member for driving the gripping nails 33 is provided on the top of the plurality of gripping nails 33 for driving the gripping nails 33 to move. The driving member includes a plurality of traction ropes 33. 9, the main shaft 38 extends to one end of the seat frame 31 and is wound and connected with multiple traction ropes 39, each traction rope 39 has multiple rope ends, and the multiple rope ends are connected to the gripping nails 33 at corresponding positions. Each gripping nail 33 is sleeved with a nail tube 32, and the nail tube 32 is fixedly connected to the seat frame 31. A connecting ring 312 is fixedly connected to the bottom of the connecting ring 312. The reset spring 311 is fixedly connected to the gripping nail 33 at the corresponding position. The two ends of the base 49 are fixedly connected. The sides are fixedly connected with a positioning member 5, which includes a polygonal sleeve 53 fixedly connected to the base 49, and a polygonal rod 51 is inserted into the polygonal sleeve 53. Two sets of polygonal holes are opened on the seat frame 31, and each set of polygonal holes has two. One set of polygonal holes is used for the seat frame 31 and the base 49 to be parallel, and the polygonal rod 51 is inserted into the polygonal hole for positioning. The other set of polygonal holes is used for the seat frame 31 to be rotated to a perpendicular state to the base 49, and the polygonal rod 51 is inserted into the polygonal hole for positioning. The initial state Under the present invention, the seat frame 31 and the base 49 are in a parallel state, the return spring 311 is in a compressed state, and the traction rope 39 is in a wound and reeled state. When the seat frame 31 needs to be rotated, the polygonal rod 51 is pulled out from the polygonal hole, and force is applied to control the seat frame 31 to rotate perpendicular to the base 49. At this time, the traction rope 39 will be loosened by the rotation of the seat frame 31, and the grasping spikes 33 will be driven by the elastic force of the return spring 311 to extend to the outside of the porous plate 34, and then inserted into the soft ground to fix the scissor jack to the ground. An auxiliary support mechanism 4 is provided in the scissor-type arm 2, and a hollow groove is provided in the middle of the two bottom rods 22. The auxiliary support mechanism 4 includes two side support rods 41 rotatably connected to the hollow groove, and a locking member is provided on one side of the side support rod. The locking member includes two locking plates 42 fixedly connected to the two side support rods 41 respectively, and each locking plate 42 is inserted with a positioning fork 43, and each positioning fork 43 is fixedly connected with a short-circuit shaft 44, and each short-circuit shaft 44 is rotatably connected to the scissor-type arm 2. A torsion spring 45 is fixedly connected to each short-circuit shaft 44, and the torsion spring 45 is fixedly connected to the scissor-type arm 2.

[0031] One end of the main shaft 38 extending into the base 49 is rotatably connected to a turntable 37 , which is fixedly connected to the seat frame 31 . The top of the turntable 37 is fixedly connected to two unlocking rods 48 for contacting the positioning fork 43 .

[0032] During the process of the seat frame 31 rotating to a state perpendicular to the base 49, the seat frame 31 will drive the turntable 37 and the unlocking rod 48 connected in sequence to rotate, so that the unlocking rod 48 squeezes the two positioning forks 43 to rotate them. When the positioning fork 43 rotates to a state of disconnection from the locking plate 42, one end of the two side support rods 41 rotates and hangs down due to the action of gravity, and is inserted into the soft soil under the action of gravity.

[0033] It should be noted that there are four groups of gripping spikes 33, each group has three gripping spikes 33, and each group of gripping spikes 33 shares a traction rope 39. The traction rope 39 has three rope ends, which are respectively connected to the gripping spikes 33 at corresponding positions.

[0034] See also Figure 5 The anti-dump mechanism 3 is provided with a ramp self-locking assembly 6. This assembly includes a blocking plate 35 that slides within the porous plate 34 and is used to block the holes in the porous plate 34. The assembly also includes a lifting screw 61 that pushes two of the gripping spikes 33 to adjust the angle between the seat frame 31 and the porous plate 34. Handles 36 are provided on both sides of the blocking plate 35, and a sliding opening is provided in the porous plate 34 for the handles 36 to slide. Two of the nail barrels 32 near the lifting screw 61 are provided with lifting openings, and fan-shaped rods 66 are slidably connected to the two lifting openings. Inside the lifting openings of the nail barrel 32, two fan-shaped rods 66 are vertically stacked. An internal threaded sleeve 62 is fixedly connected to the 31, and the lifting screw 61 is threadedly connected to the internal threaded sleeve 62. One end of the lifting screw 61 extending into the interior of the seat frame 31 is rotatably connected to a pressure plate 63, which is arranged above the two fan-shaped rods 66. A connecting rod 1 64 is rotatably connected to the seat frame 31, and a connecting rod 2 65 is rotatably connected to the connecting rod 1 64. The connecting rod 2 65 is rotatably connected to the porous plate 34.

[0035] When the scissor jack is used on a slope, the porous plate 34 is made to fit with the slope, and the traction of the traction rope 39 on the gripping spikes 33 is loosened by rotating the seat frame 31, and then the blocking plate 35 is pushed to move, so that the holes in the blocking plate 35 corresponding to the porous plate 34 are staggered, thereby blocking the holes in the porous plate 34. Then, force is applied to the lifting screw 61 to screw it into the seat frame 31, so that the pressure plate 63 squeezes the two fan-shaped rods 66, so that the two fan-shaped rods 66 drive the two gripping spikes 33 to move. The movement of the gripping spikes 33 expands and adjusts the angle between the porous plate 34 and the seat frame 31, so that the supporting surface fits with the load-bearing object, balances the lateral force, and utilizes the self-locking effect of the inclined surface to prevent the scissor jack from sliding, so that the scissor jack can easily lift the car even on a slope, making it convenient to change the car tire.

[0036] In this embodiment, the specific implementation steps for using the scissor jack on soft ground are as follows: S1. In the initial state, the seat frame 31 and the base 49 are parallel, the return spring 311 is compressed, and the traction rope 39 is wound and reeled. When the seat frame 31 needs to be rotated, the polygonal rod 51 is pulled out of the polygonal hole, and force is applied to control the seat frame 31 to rotate perpendicular to the base 49. At this time, the traction rope 39 will be loosened by the rotation of the seat frame 31, and the gripping spikes 33 will be driven by the elastic force of the return spring 311 to extend to the outside of the porous plate 34, and then inserted into the soft ground to fix the scissor jack to the ground; S2. During the process of the seat frame 31 rotating to a position perpendicular to the base 49, the seat frame 31 will drive the turntable 37 and the unlocking rod 48 connected in sequence to rotate, so that the unlocking rod 48 squeezes the two positioning forks 43 to rotate. When the positioning forks 43 rotate to a state of disconnection from the locking plate 42, one end of the two side support rods 41 rotates and hangs down by the action of gravity, and is inserted into the soft ground under the action of gravity. The rotation of the seat frame 31 triggers the two side support rods 41 to rotate and be inserted into the soft ground under the action of gravity, forming a vertical and horizontal two-way ground support with the plurality of gripping spikes 33, which not only expands the contact area between the scissor jack and the soft ground, but also further improves the placement stability of the scissor jack.

[0037] It should be understood that the above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with this technology to understand the content of the present invention and implement it accordingly. It cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, they can make some simple deductions or substitutions without departing from the concept of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A scissor jack, characterized in that: The invention comprises a tray (1) arranged on the top of a scissor-type arm (2) for connecting with a car, a base (49) being arranged at the bottom of the scissor-type arm (2), an anti-dumping mechanism (3) being arranged below the base (49), the anti-dumping mechanism (3) comprising a seat frame (31) and a porous plate (34), a main shaft (38) being rotatably connected to the seat frame (31), the main shaft (38) being fixedly connected to the base (49), a plurality of ground-gripping spikes (33) being arranged between the seat frame (31) and the porous plate (34), a driving member being arranged on the top of the plurality of ground-gripping spikes (33) for driving the ground-gripping spikes to move, and when the seat frame (31) is rotated to a state perpendicular to the base (49), the ground-gripping spikes (33) are driven by the driving member to extend out of the porous plate (34) and be inserted into the soft soil; An auxiliary support mechanism (4) is provided in the scissor-type arm (2), and the auxiliary support mechanism (4) includes two side support rods (41) rotatably connected to the scissor-type arm (2). A locking member is provided on one side of the side support rod. When the seat frame (31) is rotated to a vertical state with the base (49), the anti-dumping mechanism (3) releases the activity restriction on the auxiliary support mechanism (4) through the locking member, so that the two side support rods (41) are rotated by gravity and inserted into the soft soil.

2. A scissor jack according to claim 1, characterized in that: The anti-dumping mechanism (3) is provided with a slope self-locking assembly (6), the slope self-locking assembly (6) comprising a blocking plate (35) slidably arranged in the porous plate (34), the blocking plate (35) being used to block the holes of the porous plate (34), the slope self-locking assembly (6) further comprising a lifting screw (61), the lifting screw (61) adjusting the angle between the seat frame (31) and the porous plate (34) by pushing two of the gripping spikes (33) to move.

3. A scissor jack according to claim 1, characterized in that: The driving member includes a plurality of traction ropes (39), one end of the main shaft (38) extending into the seat frame (31) is wound and connected with the plurality of traction ropes (39), each of the traction ropes (39) has a plurality of rope ends, and the plurality of rope ends are connected to the ground-gripping nails (33) at corresponding positions, each of the ground-gripping nails (33) is sleeved with a nail tube (32), the nail tube (32) is fixedly connected to the seat frame (31), and a connecting ring (312) is fixedly connected to the inside of each nail tube (32), and a reset spring (311) is fixedly connected to the bottom of the connecting ring (312), and the reset spring (311) is connected to the ground-gripping nail (33) at corresponding positions.

4. A scissor jack according to claim 1, characterized in that: The locking member comprises two locking plates (42) respectively fixedly connected to the two side support rods (41); a positioning fork (43) is inserted into each locking plate (42); a short-circuit shaft (44) is fixedly connected in each positioning fork (43); each short-circuit shaft (44) is rotatably connected to the scissor arm (2); each short-circuit shaft (44) is fixedly connected to a torsion spring (45); and the torsion spring (45) is fixedly connected to the scissor arm (2).

5. A scissor jack according to claim 4, characterized in that: One end of the main shaft (38) extending into the base (49) is rotatably connected to a turntable (37), the turntable (37) is fixedly connected to the seat frame (31), and the top of the turntable (37) is fixedly connected to two unlocking rods (48) for contacting the positioning fork (43).

6. A scissor jack according to claim 2, characterized in that: Handles (36) are provided on both sides of the blocking plate (35), and a sliding opening for the handles (36) to slide is provided in the porous plate (34).

7. A scissor jack according to claim 3, characterized in that: Two nail barrels (32) close to the lifting screw (61) are provided with lifting openings, and fan-shaped rods (66) are slidably connected in the two lifting openings. In the lifting openings of the nail barrel (32), the two fan-shaped rods (66) are vertically stacked. An internal threaded sleeve (62) is fixedly connected in the seat frame (31), and the lifting screw (61) is threadedly connected to the internal threaded sleeve (62). One end of the lifting screw (61) extending to the inside of the seat frame (31) is rotatably connected to a pressure plate (63), and the pressure plate (63) is arranged above the two fan-shaped rods (66).

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