Double trigger ratchet lifting jack

Abstract

The utility model relates to a double-pull machine ratchet wheel lifting jack, including the pole of ascending and descending, the lifting main body of movable sleeve setting on it, support base and lifting plate. The fixed plate is vertically arranged in the middle part of the lifting main body and divides the cavity into upper and lower parts. The fixed handle is arranged in the middle part of the lifting main body, the down micro -adjustment trigger, the release trigger and the supporting sheet are located in the lower cavity, and the driving trigger is located in the upper cavity. The two ends of the first spring are horizontally abutted against the lifting main body and the supporting sheet. The driving unit is arranged in the upper cavity and connected with the driving plate trigger. The down micro -adjustment trigger is rotatably connected with the lifting main body through the first pin shaft, the lower side surface is provided with a convex pressing head, and the right side end part is provided with a micro -adjustment handle. The micro -adjustment sleeve is pivoted with the first pin shaft. The release trigger is pivoted with the lifting main body through the second pin shaft and abuts against the supporting sheet through the release rod, and the right side end part is provided with a release handle. The fixed handle is rotatably abutted against the driving sheet. Its advantage lies in that the micro -adjustment trigger of small stroke step back is additionally arranged, the existing function is reserved, and the back stroke accurate adjustment is realized.

Description

Technical Field

[0001] This utility model relates to the field of clamping technology, specifically a double-trigger ratchet lifting jack. Background Technology

[0002] A ratchet lifting jack is a type of jack that can achieve unidirectional step lifting stroke. Because it can complete a certain step in a single operation and has the effect and function of stopping backwards, it is similar to the function of a ratchet and is therefore called a ratchet lifting jack in the jack industry.

[0003] Existing ratchet lifting jacks typically feature a drive trigger and a release trigger. The drive trigger propels the lifting section of the jack in a unidirectional stepping motion, while the release trigger releases the locking mechanism on the lifting section, allowing it to retract. This is a common feature in the field. This structure meets basic requirements for conventional lifting operations. However, because the drive trigger's single-step stroke is fixed, each operation can only achieve a fixed unidirectional stroke. In practical applications, when the lifting stroke exceeds the required lifting amount, precise adjustment is impossible. Similarly, directly operating the release trigger for retraction makes it difficult to precisely control the retraction stroke, resulting in insufficient positioning accuracy. This accuracy deficiency is particularly pronounced in operations with strict lifting height requirements, limiting the application range of ratchet lifting jacks. Therefore, there is an urgent need to design a fine-tuning trigger capable of small-stroke step retraction to compensate for the lack of fine adjustment capabilities in existing technologies.

[0004] In applications of ratchet lifting jacks, due to the significant weight of the object being lifted, a large driving force is required to complete the stepping motion. Operators often habitually operate the driving trigger by foot to improve the efficiency and convenience of applying force; this method has become a common practice in the industry. When performing retraction and fine-tuning operations, operators typically choose to use their hands to drive the fine-tuning trigger. This is because the weight of the lifted object itself provides an auxiliary force during retraction, eliminating the need for a large driving force on the fine-tuning trigger; the strength of the hand is sufficient for the operation. Furthermore, hand operation offers significantly higher control precision than foot operation, making it more suitable for achieving fine-tuning adjustments.

[0005] However, in actual operation, because the ratchet jack has a relatively compact structure and requires a fixed handle and several triggers with different functions, the operator is very likely to accidentally trigger another trigger while driving any one of the triggers, causing the jack to fall unexpectedly or jam due to conflict between different triggers.

[0006] At the same time, the trigger release mechanism must retain its quick release and retraction function to cope with usage scenarios that require rapid descent. This requires that the three triggers be both independent and coordinated in function.

[0007] Therefore, how to reasonably arrange the relative positions of the release trigger, drive trigger, and retract fine-tuning trigger to avoid mutual interference during operation, while ensuring that the functions of each trigger are clear and easy to operate, and to guarantee the original lifting function, locking stability, and safety of the ratchet jack, has become an urgent technical problem that needs to be solved, and a complete technical solution is needed to address it. Utility Model Content

[0008] The purpose of this utility model is to overcome the shortcomings of the prior art and provide a double-trigger ratchet lifting jack, which adds a small-stroke step-back fine-tuning trigger to the ratchet lifting jack and reasonably arranges its relative position with the drive trigger and release trigger, so as to achieve precise adjustment of the lifting and retraction strokes while retaining the step-drive and quick-release functions.

[0009] To achieve the above objectives, a double-trigger ratchet lifting jack is designed, comprising a lifting rod, a lifting body sleeved on the lifting rod, a support base disposed at one end of the lifting rod, and a lifting plate disposed on the lifting body. It further includes: a fixing plate disposed within the cavity of the lifting body, the fixing plate dividing the cavity into a lower cavity and an upper cavity; a fixing handle disposed in the middle of one side of the lifting body; a drive trigger located above the fixing handle and connected to a lifting drive unit disposed within the upper cavity of the lifting body; a downward fine-tuning trigger located below the fixing handle, one side of the downward fine-tuning trigger and one side of the fine-tuning sleeve respectively hinged to a first pin, the first pin being located on the right side of the lifting rod; and the fine-tuning sleeve sleeved on the lifting rod. The top side of the device is connected to the fixed plate via a second spring sleeved on the lifting rod. The downward fine-tuning trigger is equipped with an anti-rotation block, which matches the shape of the anti-rotation handle on the fine-tuning sleeve, so that the fine-tuning sleeve is rotated and limited under the action of the rebound force of the second spring. Several support plates are sleeved on the lifting rod and located below the fine-tuning sleeve. The left end of the support plate is connected to the support limiting part on the lifting body, and the lower part of the right end of the support plate is connected to the inner cavity of the lifting body via a first spring. The release trigger is located between the downward fine-tuning trigger and the fixed handle, and is hinged to the lifting body via a second pin. The left end of the release trigger is equipped with a third pin, one end of the release rod is hinged to the third pin, and the other end passes through the downward fine-tuning trigger and abuts against the support plate.

[0010] Preferably, the present invention further includes: the lifting drive unit comprising: a plurality of drive plates, sleeved on the lifting rod and located in the upper cavity, the top of the left end abutting against and limiting the drive limiting part on the inner wall of the lifting body, a third through hole in the middle for the lifting rod to pass through and conforming to the cross-section of the lifting rod, two third springs respectively disposed on the left and right sides of the lifting rod in the upper cavity, the two ends of the third springs respectively abutting against the top of the fixing plate and the bottom of the drive plate; the drive plate frictionally engaging with the lifting rod through the inner wall of the third through hole; the middle part of the drive trigger is hinged to the trigger positioning cylinder fixed in the lifting body, and the right end of the drive trigger is provided with a drive handle extending from the drive through groove on the surface of the lifting body; the lower side of the middle part of the drive trigger is provided with a drive protrusion, the drive protrusion abutting against the top surface of the drive plate; the support plate and the drive plate are respectively positioned inclined to the lifting rod by the abutting of the first spring, the support limiting part, the third spring and the drive limiting part.

[0011] Preferably, the present invention further includes: a fine-tuning handle is provided at the right end of the down-adjustment trigger through the fine-tuning groove on the surface of the lifting body, and a protruding pressure head is provided at the lower part of the left end near the support plate. The protruding pressure head abuts against the top of the right end of the support plate, and a fifth through hole is provided on the fine-tuning handle.

[0012] Preferably, the present invention further includes: a second through hole in the middle of the support plate for the lifting rod to pass through and conforming to the cross-section of the lifting rod; the support plate frictionally engages with the lifting rod through the inner wall of the second through hole; a first spring applies a bias pressure to the support plate, and the bias pressure, in conjunction with the limiting part of the support, causes the support plate to tilt along the axial direction of the lifting rod, and the support plate in the tilted state is frictionally locked with the lifting rod through the second through hole.

[0013] Preferably, the present invention further includes: a fine-tuning sleeve disposed in the lower cavity, with a fourth through hole in the middle for the lifting rod to pass through and conforming to the cross-section of the lifting rod, and the lower part hinged to the first pin through a first pivot hole; the lower part of the fine-tuning sleeve has an inclined surface that abuts against the top surface of the support plate; the second spring generates a vertical thrust on the fine-tuning sleeve, which drives the fine-tuning sleeve to rotate around the first pin, and the rotational movement is limited by the cooperation of the anti-rotation block and the anti-rotation handle. The thrust of the second spring on the fine-tuning sleeve and the rotational limitation of the anti-rotation block and the anti-rotation handle together constitute a vertical non-deflection angle abutment between the fine-tuning sleeve and the support plate.

[0014] Preferably, the present invention further includes: one end of the release rod in the release trigger is hinged to the third pin, the other end abuts against the upper side of the support plate, and the release rod passes through the fifth through hole provided on the downward fine-tuning trigger to form a clearance, and the right end of the release trigger is provided with a release handle extending from the release through groove on the surface of the lifting body.

[0015] Preferably, the present invention further includes: one end of the release rod that abuts against the upper side of the support plate moves synchronously with the rotation of the release trigger around the second pin, pushing the support plate to rotate around the support limiting part and releasing the clamping lock between the support plate and the lifting rod.

[0016] Preferably, the present invention further includes: a fixing plate is horizontally arranged in the inner cavity of the lifting body, and a first through hole for the lifting rod to pass through is provided in the middle of the fixing plate.

[0017] Preferably, the present invention further includes: the support plate and the driving plate are a plurality of closely arranged metal plates.

[0018] Compared with the prior art, the advantages of this utility model are: By setting a vertical fixing plate inside the lifting body, the cavity is divided into a lower cavity and an upper cavity. In conjunction with the central layout of the fixed handle, the installation positions of the down-adjustment trigger, release trigger, and drive trigger are rationally planned. The down-adjustment trigger is located in the lower cavity below the fixed handle, the release trigger is located in the lower cavity between the down-adjustment trigger and the fixed handle, and the drive trigger is located in the upper cavity above the fixed handle. The spatial layout of the three is clear and does not interfere with each other. It not only meets the industry's conventional usage habits of step-by-step operation of the drive trigger, step-by-step retraction and full release operation of the down-adjustment trigger and release trigger, but also avoids mutual interference in different operation processes, thus improving the convenience of operation.

[0019] By utilizing the cooperation between the support plate and the first spring and the support limiting part, as well as the cooperation between the drive plate and the third spring and the drive limiting part, the support plate and the drive plate naturally form an inclined posture towards the lifting rod. Through the contoured through hole, reliable clamping and locking with the lifting rod are achieved, ensuring the locking stability and safety of the jack during the lifting process and effectively preventing the heavy object from slipping off on its own.

[0020] The synergistic action of the downward fine-tuning trigger, the fine-tuning sleeve, and the second spring can convert the lateral thrust of the second spring into bias pressure on the support plate through the inclined surface. Combined with the limiting of the anti-rotation block and the anti-rotation handle, it can achieve small-amplitude unlocking of the support plate and step-by-step locking of the lifting rod by the fine-tuning sleeve, thereby achieving small-stroke step-by-step retraction of the lifting body. This precisely compensates for the shortcomings of existing technologies that cannot finely adjust the retraction stroke, significantly improves the positioning accuracy of the lifting height, and expands the application range of jacks in scenarios with strict requirements for lifting height.

[0021] The release trigger, through the abutment of the release rod and the support plate, can quickly push the support plate to release the clamping lock on the lifting rod, retaining the rapid release and retraction function of existing technologies and meeting the needs of application scenarios requiring rapid descent. Simultaneously, the drive trigger, through the abutment of the drive protrusion and the drive plate, can reliably drive the lifting body in one-way step-by-step lifting, ensuring that the original lifting function of the jack is not affected. This achieves a coordinated unity of precise fine-tuning, rapid release, and stable lifting, balancing operational accuracy, efficiency, and safety. Attached Figure Description

[0022] Figure 1 This is a rear view of the overall structure of this utility model; Figure 2 This is a front view of the overall structure of this utility model; Figure 3 This is an exploded view of the overall structure of this utility model from a tilted left perspective; Figure 4 and Figure 5 This is an exploded view of the overall structure of this utility model from a tilted right perspective; In the diagram: 1. Lifting boom; 101. Support base; 102. First arrow; 103. Second arrow; 2. Lifting body; 201. Lifting plate; 202. Support limiting part; 203. Drive limiting part; 210. Lower cavity; 211. Upper cavity; 220. Fine-tuning through groove; 221. Release through groove; 222. Drive through groove; 3. Fixing plate; 301. First through hole; 302. Fixing handle; 4. Support plate; 401. Second through hole; 402. First spring; 403. First receiving groove; 5. Drive plate; 501. Third through hole; 510. Third spring; 511. Second receiving groove; 6. Downward fine-tuning trigger; 601. First pin; 602. Fine-tuning handle; 610. Protruding pressure head; 620. Fifth through hole; 621. Anti-rotation block; 7. Fine-tuning sleeve; 701. Fourth through hole; 702. Second spring; 703. First pivot hole; 710. Inclined surface; 720. Anti-rotation handle; 8. Release trigger; 801. Second pin; 802. Third pin; 810. Release lever; 820. Release handle; 9. Drive trigger; 901. Trigger positioning cylinder; 902. Drive handle; 910. Drive protrusion. Detailed Implementation

[0023] To make the purpose, principle and structure of this utility model clearer, the following description is provided in conjunction with the accompanying drawings and specific embodiments.

[0024] See Figure 1-5 This utility model provides a double-trigger ratchet lifting jack.

[0025] The basic support structure of the double-trigger ratchet lifting jack includes: a lifting rod 1, a lifting body 2, a support base 101, and a lifting plate 201. The lifting rod 1 is a long strip-shaped rod, one end of which is fixedly connected to the support base 101. The support base 101 has a multi-legged bent structure, which can be stably placed on the ground or a support plane to prevent the jack from sliding during the stress process.

[0026] The lifting body 2 is a hollow rectangular shell structure, movably fitted onto the lifting rod 1 through a through-hole, and can move up and down along the axial direction of the lifting rod 1. The lifting plate 201 is fixed to the outer wall of the lifting body 2 with bolts. The lifting plate 201 is an L-shaped bent structure. One bent section of the lifting plate 201 has several countersunk holes for connection to the outer wall of the lifting body 2 with bolts, while the other bent section is a flat support surface for supporting the load to be lifted. Preferably, the support surface of the lifting plate 201 can be parallel to the support base 101. When the lifting body 2 moves upward along the lifting rod 1, the lifting plate 201 simultaneously lifts the load upward; when the lifting body 2 moves downward, the lifting plate 201 lowers the load accordingly.

[0027] Inside the internal cavity of the lifting body 2, a fixing plate 3 is horizontally fixed. It is installed on the inner wall of the lifting body 2 by welding, bolting, or integral molding with the lifting body 2, dividing the internal cavity of the lifting body 2 into an independent lower cavity 210 and an upper cavity 211. The lower cavity 210 and the upper cavity 211 are distributed along the axial direction of the lifting rod 1, and their spatial size is adapted to the installation requirements of subsequent functional components. A first through hole 301 is provided in the middle of the fixing plate 3. The cross-sectional shape of the first through hole 301 is consistent with the cross-sectional shape of the lifting rod 1. The lifting rod 1 passes through the first through hole 301, ensuring smooth relative sliding between the lifting rod 1 and the fixing plate 3.

[0028] A fixed handle 302 is also fixedly installed in the middle of the outer wall of the lifting body 2. The fixed handle 302 is a cylindrical or rectangular rod. The operator can adjust the overall position of the jack by holding the fixed handle 302. At the same time, the fixed handle 302 also serves to separate the triggers, so that the positions of the subsequently installed down-adjustment trigger 6, release trigger 8 and drive trigger 9 are more regular. It also acts as a barrier when the operator drives the down-adjustment trigger 6, release trigger 8 and drive trigger 9, preventing the operator from accidentally touching one trigger while operating one trigger.

[0029] The lower cavity 210 is equipped with a support plate 4, a first spring 402, a downward fine-tuning trigger 6, a fine-tuning sleeve 7, and a release trigger 8. The installation positions and action coordination of each component are as follows.

[0030] The support plate 4 consists of several rectangular metal plates of the same shape arranged close together. It is positioned within the lower cavity 210 near the lower side wall of the lifting body 2. The support plate 4 is sleeved on the lifting rod 1. One left end of the support plate 4 is connected to a support limiting part 202 on the inner left side wall of the lifting body 2. The support limiting part 202 is an integrally formed through-slot structure on the inner side wall of the lifting body 2. The support plate 4 is engaged within the through-slot structure, limiting its top end. Preferably, there is a minute gap between the support plate 4 and the through-slot structure of the support limiting part 202. This minute gap is smaller than the thickness of a single metal plate in the support plate 4, allowing the support plate 4 to rotate and swing slightly within the through-slot structure of the support limiting part 202 while being limited by the support limiting part 202 to prevent it from falling out.

[0031] The support plate 4 has a second through hole 401 in the middle. The cross-sectional shape of the second through hole 401 is similar to that of the lifting rod 1. That is, the diameter of the second through hole 401 is slightly larger than the outer diameter of the lifting rod 1, and one side of the hole wall is in close contact with the outer wall of the lifting rod 1. When the support plate 4 is tilted, it forms a large static friction force with the lifting rod 1. The first spring 402 is vertically arranged in the lower cavity 210. One end of the spring abuts against the lower inner wall of the lifting body 2, and the other end abuts against the lower part of the right side of the support plate 4. When the first spring 402 is in a naturally extended state, it will apply a biasing force in the direction of the second arrow 103 to the support plate 4. This biasing force cooperates with the limiting effect of the support limiting part 202 on the left end of the support plate 4, so that the support plate 4 is tilted in the axial direction of the lifting rod 1. The left end of the support plate 4 cannot move in the direction of the second arrow 103 under the obstruction of the support limiting part 202, while the right end is pushed in the direction of the second arrow 103 by the first spring 402. This causes the hole wall of the second through hole 401 to be tightly locked with the outer wall of the lifting rod 1 under normal conditions through friction, forming a one-way locking structure. At this time, the lifting body 2 cannot move down the lifting rod 1 by itself, realizing the locking and anti-slip effect when the jack is stationary while carrying a heavy object.

[0032] Preferably, a first receiving groove 403 is provided on the inner side wall of the lifting body 2 at the position corresponding to the first spring 402. The first receiving groove 403 is contoured to the first spring 402 and is used to limit the first spring 402. The axial length of the groove of the first receiving groove 403 is less than the axial length of the first spring 402 when it abuts against the support plate 4, so that part of the first spring 402 extends out of the first receiving groove 403 and can be compressed under elastic deformation.

[0033] The down-adjustment trigger 6 is located in the lower cavity 210 below the fixed handle 302, and between the support plate 4 and the fixed plate 3. The down-adjustment trigger 6 is an irregular metal rod with a first pin 601 that passes through the front and rear sides in the middle. It is rotatably connected to the inner wall of the lifting body 2 through the first pin 601. The inner wall of the lifting body 2 has corresponding pivot holes that cooperate with the two ends of the first pin 601. The first pin 601 passes laterally through the down-adjustment trigger 6 and the side wall of the lifting body 2, so that the down-adjustment trigger 6 can rotate around the axis of the first pin 601. The right end of the downward fine-tuning trigger 6 extends through the fine-tuning slot 220 on the side wall of the lifting body 2 to the outside of the lifting body 2, and a fine-tuning handle 602 is fixedly connected to the extended end. The depth of the fine-tuning slot 220 can be set as needed to limit the stroke of the fine-tuning handle 602 of the downward fine-tuning trigger 6, thereby limiting the rotational stroke of the downward fine-tuning trigger 6. By controlling the rotational stroke of the downward fine-tuning trigger 6, the step stroke of the downward fine-tuning trigger 6 can be adjusted in subsequent operations. The deeper the fine-tuning slot 220, the greater the rotational stroke of the downward fine-tuning trigger 6, the greater the pushing amplitude on the support plate 4, and the greater the step stroke of the downward fine-tuning. Therefore, only the depth of the fine-tuning slot 220 needs to be controlled to achieve control over the accuracy of the downward fine-tuning step stroke of the downward fine-tuning trigger 6.

[0034] The fine-tuning handle 602 has an arc-shaped or straight rod-shaped structure. The operator can move the fine-tuning handle 602 by hand to drive the downward fine-tuning trigger 6 to rotate around the first pin 601. On the left side of the downward fine-tuning trigger 6 near the lower side of the support plate 4, a protruding pressure head 610 is integrally formed. The protruding pressure head 610 is arc-shaped or right-angled. When the downward fine-tuning trigger 6 rotates, the protruding pressure head 610 can contact the upper side of the support plate 4 and apply pressure. At the same time, a fifth through hole 620 is also opened inside the downward fine-tuning trigger 6. The fifth through hole 620 is a rectangular or circular through hole for the subsequent release rod 810 to pass through.

[0035] The fine-tuning sleeve 7 is fitted onto the lifting rod 1 and located within the lower cavity 210, between the support plate 4 and the fixing plate 3. The fine-tuning sleeve 7 is a hollow metal sleeve with a fourth through hole 701 in its middle. The cross-sectional shape of the fourth through hole 701 is similar to that of the lifting rod 1, through which the lifting rod 1 passes, allowing the fine-tuning sleeve 7 to slide along the axial direction of the lifting rod 1 or rotate slightly around it. A first pivot hole 703 is provided on the right side of the fine-tuning sleeve 7. A first pin 601 passes through both the first pivot hole 703 and the downward fine-tuning trigger 7, allowing the fine-tuning sleeve 7 and the downward fine-tuning trigger 7 to rotate together around the first pin 601, achieving linkage between the two. The lower side of the fine-tuning sleeve 7 is an inclined surface 710, which fits against the upper side of the support plate 4. The inclination angle of the inclined surface 710 is the same as that of the support plate 4. The upper side of the fine-tuning sleeve 7 is abutted against a second spring 702. The second spring 702 is sleeved on the lifting rod 1. One end of the spring abuts against the upper side of the fine-tuning sleeve 7, and the other end abuts against the lower side of the fixing plate 3. The second spring 702 is always in a compressed state, applying a lateral thrust to the fine-tuning sleeve 7 in the direction of the first arrow 102.

[0036] When the lateral thrust acts on the fine-tuning sleeve 7, it will push the fine-tuning sleeve 7 to rotate around the first pin 601 in the direction of the first arrow 102. The inclined surface 710 of the fine-tuning sleeve 7 will convert the rotational force into pressure on the support plate 4 in the direction of the first arrow 102, further enhancing the clamping force between the support plate 4 and the lifting rod 1, and ensuring the stability of the lock.

[0037] In addition, an anti-rotation block 621 is fixed on the front side of the downward fine-tuning trigger 6, and an anti-rotation handle 720 is integrally formed on the right end of the fine-tuning sleeve 7. The anti-rotation block 621 is a rectangular protrusion, and the anti-rotation handle 720 is an extended thin plate structure. The anti-rotation handle 720 is similar in shape to the anti-rotation block 621. When the fine-tuning sleeve 7 rotates around the first pin 601 under the lateral thrust of the second spring 702, the anti-rotation handle 720 abuts against the anti-rotation block 621, and the rotation of the fine-tuning sleeve 7 is restricted. This prevents the fine-tuning sleeve 7 from rotating excessively, so that the tilt angle between the inclined surface 710 and the support plate 4 remains consistent. It also ensures that the fourth through hole 701 of the fine-tuning sleeve 7 does not come into frictional contact with the lifting rod 1 when it is not in working state, thus ensuring that the pressure direction, deflection angle, and force of the fine-tuning sleeve 7 on the support plate 4 are constant (in the normal static state of bearing heavy objects).

[0038] The release trigger 8 is located inside the lower cavity 210 and between the downward fine-tuning trigger 6 and the fixed handle 302. The release trigger 8 is a metal rod, the middle of which is pivotally connected to the inner wall of the lifting body 2 through the second pin 801. The second pin 801 passes laterally through the release trigger 8 and the side wall of the lifting body 2, so that the release trigger 8 can rotate around the second pin 801. A third pin 802 is fixedly provided on the left end of the release trigger 8. A release rod 810 is pivotally connected to the third pin 802. The release rod 810 is a slender metal rod. One end of the rod is connected to the third pin 802 through a bushing and can rotate around the third pin 802. The other end passes through the fifth through hole 620 on the down-adjustment trigger 6 and extends to the upper side of the support plate 4 and abuts against it. The right side of the release trigger 8 extends outward through the release through slot 221 opened on the side wall of the lifting body 2. A release handle 820 is fixedly connected to the extended end. The structure of the release handle 820 is similar to that of the fine-adjustment handle 602. The operator can move the release handle 820 by hand to drive the release trigger 8 to rotate around the second pin 801, and then push the support plate 4 to move through the release rod 810.

[0039] A lifting drive unit is installed inside the upper cavity 211. The lifting drive unit includes: a drive plate 5, two third springs 510, and a drive trigger 9. The installation and operation of each component are as follows: The drive plate 5 consists of several rectangular metal plates of the same shape arranged close together. It is located inside the upper cavity 211 near the fixed plate 3. The upper side of the left end of the drive plate 5 abuts against the drive limiting part 203 on the inner side wall of the upper side of the lifting body 2. The drive limiting part 203 is a protruding structure integrally formed on the inner side wall of the lifting body 2, which limits the left end of the drive plate 5. A third through hole 501 is opened in the middle of the drive plate 5. The cross-sectional shape of the third through hole 501 is similar to the cross-sectional shape of the lifting rod 1. Its diameter is slightly larger than the outer diameter of the lifting rod 1. In the working state, its hole wall is tightly attached to the outer wall of the lifting rod 1 to generate a large static friction force. Two third springs 510 are respectively disposed in the upper cavity 211 on the left and right sides of the lifting rod 1, and both are in a vertical state. One end of each third spring 510 abuts against the upper side of the fixing plate 3, and the other end abuts against the lower side of the drive plate 5. The two third springs 510 have the same elastic force. When in a naturally extended state, they apply a biasing force in the direction of the second arrow 103 to the drive plate 5. This biasing force cooperates with the limiting effect of the drive limiting part 203 on the left end of the drive plate 5, so that the drive plate 5 is tilted to the axial direction of the lifting rod 1. Unable to move in the direction of the second arrow 103 due to the obstruction of the drive limiting part 203, the lower part is pushed in the direction of the second arrow 103 by the third spring 510, causing the drive plate 5 to be tilted relative to the lifting rod 1 in the non-working state, and keeping the hole wall of the third through hole 501 from contacting and rubbing against the outer wall of the lifting rod 1 in the non-working state. At this time, a part of the stroke of the third spring 510 located on the left is blocked and limited by the drive limiting part 203. The amount of spring formation is converted into elastic potential energy to press the drive plate 5 tightly against the drive limiting part 203. When a force is applied to the upper side of the right end of the drive plate 5 in the direction of the first arrow 102, the drive plate 5 moves toward the direction of the third spring 510. Both the left and right third springs 510 are compressed, and the left end of the drive plate 5 leaves the drive limiting part 203 and releases its abutment. Since the drive plate 5 is tilted and the force is applied to the right end of the drive plate 5, the compression stroke of the third spring 510 on the right is greater than that of the third spring 510 on the left, which increases the tilt angle of the drive plate 5 and causes the drive plate 5 to form a tilting motion tendency toward the direction of the first arrow 102 and the right side. At this time, the hole wall of the third through hole 501 of the drive plate 5 engages with the lifting rod 1 to form a large static friction force, forming a one-way locking structure similar to the support plate 4. At this time, the drive plate 5 only allows the lifting body 2 to move upward along the lifting rod 1.

[0040] Preferably, two second receiving grooves 511 are provided on the left and right sides of the upper side of the fixing plate 3, respectively. The second receiving grooves 511 are similar in shape to the third spring 510 and are used to limit the third spring 510. The axial length of the groove of the second receiving groove 511 is less than the axial length of the third spring 510 when it abuts against the drive plate 5, so that part of the third spring 510 extends out of the second receiving groove 511 and can be compressed under elastic deformation.

[0041] The drive trigger 9 is located in the upper cavity 211 above the fixed handle 302 and above the drive plate 5. The drive trigger 9 is a metal rod with a trigger positioning cylinder 901 in its middle. The trigger positioning cylinder 901 is horizontally fixed on the inner wall of the lifting body 2. The drive trigger 9 is sleeved on the trigger positioning cylinder 901 through the round hole in the middle and can rotate around the trigger positioning cylinder 901. The right end of the drive trigger 9 extends outward through the drive through slot 222 opened on the side wall of the lifting body 2, and a drive handle 902 is fixedly connected to the extended end. The length of the drive handle 902 is slightly longer than that of the fine adjustment handle 602 and the release handle 820, which is adapted to the operating habits of the operator. A drive protrusion 910 is integrally formed on the lower side of the middle part of the drive trigger 9. The drive protrusion 910 is an arc-shaped protrusion, and its position corresponds to the upper side of the drive plate 5. When the drive trigger 9 rotates around the trigger positioning cylinder 901, the drive protrusion 910 can contact the upper side of the drive plate 5 and apply pressure in the direction of the first arrow 102.

[0042] In addition, both the support plate 4 and the drive plate 5 adopt a structure in which several metal plates are arranged close together, usually 3-5 metal plates are set. The structure of multiple plates stacked can enhance the overall strength of the support plate 4 and the drive plate 5. At the same time, the friction between the through hole wall of the support plate 4 and the drive plate 5 and the lifting rod 1 can be divided into multiple independent areas. When the friction coefficient of a certain metal plate decreases due to long-term friction wear, the friction force is reinforced by the adjacent metal plates to avoid friction failure of the support plate 4 or the drive plate 5. The top surfaces of the second through hole 401 of the support plate 4 and the third through hole 501 of the drive plate 5 are roughened, which increases the friction force between the hole wall and the outer wall of the lifting rod 1, further improving the reliability of clamping and locking, and preventing the lifting body 2 from accidentally sliding when carrying heavy objects.

[0043] The working process of this double-trigger ratchet lifting jack is divided into a lifting process, a fine-tuning and retraction process, and a rapid retraction process. The operating principles of each process are as follows: (I) Improvement process: The operator must first place the object to be lifted on the lifting plate 201, and then step on the drive handle 902 in the direction of the first arrow 102. The drive handle 902 drives the drive trigger 9 to rotate clockwise around the trigger positioning cylinder 901 (taking the device with the support base 101 on the lower side, the lifting body 2 on the upper side, and the fixed handle 302 on the right side as a front reference). The drive protrusion 910 in the middle of the drive trigger 9 rotates together and applies pressure in the direction of the first arrow 102 to the upper side of the drive plate 5. This pressure overcomes the biasing force of the third spring 510 on the drive plate 5 in the direction of the second arrow 103, pushing the drive plate 5 away from the drive limit part 203 to release the abutment. Furthermore, by applying force to the lower third spring 510, the deformation stroke between the upper and lower third springs 510 is controlled to be different, increasing the tilt angle of the drive plate 5 and causing a rotational tilt. This increases the clamping force between the wall of the third through hole 501 and the outer wall of the lifting rod 1. At this time, the drive plate 5 locks onto the lifting body 2, and the drive plate 5 generates a frictional locking anti-slip effect on the lifting rod 1, thus pushing the lifting body 2 to move upwards along the axis of the lifting rod 1. This lifting principle is existing technology in the field.

[0044] (II) Fine-tuning rollback process: When the height of the load exceeds the required height and a small-stroke retraction adjustment is needed, the operator moves the fine-tuning handle 602 towards the lifting body 2. The fine-tuning handle 602 drives the downward fine-tuning trigger 6 to rotate counterclockwise around the first pin 601 (taking the support base 101 on the lower side of the device, the lifting body 2 on the upper side, and the fixed handle 302 on the right side as a front reference). The protruding pressure head 610 on the upper part of the downward fine-tuning trigger 6 rotates together, applying pressure to the upper side of the support plate 4 in the direction of the first arrow 102. The pressure overcomes the biasing force of the first spring 402 on the support plate 4 in the direction of the second arrow 103, compresses the first spring 402, and pushes the support plate 4 to rotate around the abutment point of its left end and the support limiting part 202 in the direction of the first arrow 102, so that the tilt angle of the support plate 4 is reduced, and the friction clamping force between the hole wall of the second through hole 401 and the outer wall of the lifting rod 1 is partially released (not completely released). At this time, the lifting body 2 will slowly descend a short distance along the lifting rod 1 under the action of the weight of the heavy object, realizing fine adjustment and retraction. After completing a certain distance of height descent, the support plate 52 will automatically restore the friction lock on the lifting rod 1.

[0045] During this process, the downward fine-tuning trigger 6 rotates around the first pin 601, so the anti-rotation block 621 will move away from the anti-rotation handle 720 under the action of rotation, releasing the rotation limit effect between the lower anti-rotation handle 720 and the anti-rotation block 621 of the fine-tuning sleeve 7, so that the fine-tuning sleeve 7 can be pushed by the second spring to rotate under bias. Since the fourth through hole 701 is set on the fine-tuning sleeve 7, when the fine-tuning sleeve 7 rotates to a certain extent, the fourth through hole 701 will also rotate counterclockwise accordingly. When it rotates to a certain stroke, the inner wall of the fourth through hole 701 forms a partial friction lock with the lifting rod 1. At this time, the fine-tuning sleeve 7 and the support plate 4, which has already released some friction, together form friction with the lifting rod 1, preventing the support plate 4 from being completely released due to excessive tilt angle, thereby preventing the lifting body 2 from falling suddenly. At the same time, the anti-rotation block 621 limits the anti-rotation handle 720, ensuring that the rotation angle of the fine-tuning sleeve 7 is stable, so that the clamping force of the support plate 4 is always kept within the range of "slowly descending but not falling suddenly", ensuring the accuracy of fine-tuning retraction, and preventing the jack from falling due to a full release without locking during the fine-tuning retraction step action.

[0046] When the body retracts to the desired height, the operator releases the fine-tuning handle 602. The downward fine-tuning trigger 6 resets under the opening action of the first spring 402. The pressure of the protruding pressure head 610 on the support plate 4 disappears. The first spring 402 pushes the support plate 4 back to its tilted position. The second through hole 401 and the lifting rod 1 are re-clamped and locked, and the lifting body 2 stops retracting.

[0047] Since the down-adjustment trigger 6 can automatically return to the position before the trigger is pulled, and the support plate 4 can automatically resume locking the lifting rod 1 after sliding for a certain period of time when some friction is released, the height of the lifting body 2 can be gradually reduced by pulling the down-adjustment trigger 6 to lower the body by one step at a time.

[0048] (III) Full release rollback process: When it is necessary to quickly lower the heavy object to the initial position, the operator manually pulls the release handle 820. The release handle 820 drives the release trigger 8 to rotate counterclockwise around the second pin 801 (taking the device with the support base 101 on the lower side, the lifting body 2 on the upper side, and the fixed handle 302 on the right side as an example for frontal reference). The third pin 802 on the upper part of the release trigger 8 rotates together, and under the action of rotation, the third pin 802 moves closer to the support plate 4 in the direction of the first arrow 102. The third pin 802 drives the release rod 810, which is pivotally connected to it, to move closer to the support plate 4. The other end of the release rod 810 applies a thrust in the direction of the first arrow 102 to the upper side of the support plate 4. The thrust is greater than the bias force of the first spring 402, causing the support plate 4 to rotate downwards significantly, completely eliminating its tilted posture. The clamping force between the wall of the second through hole 401 and the outer wall of the lifting rod 1 is completely released. At this time, since the fine-tuning sleeve 7 and the drive plate 5 are not locked to the lifting rod 1, there is no friction between the lifting body 2 and the lifting rod 1, allowing them to slide freely. Under the influence of the weight, the lifting body 2 can quickly descend along the lifting rod 1 until it contacts the support base 101, completing the rapid retraction. When the weight descends to the target position, the operator releases the release handle 820. The first spring 402, compressed when the release handle 820 is squeezed, releases its elastic potential energy, pushing the support plate 4 back to its initial position. The support plate 4 also pushes the release lever 810 to push the release trigger 8 out and reset. The thrust of the release lever 810 on the support plate 4 disappears, and the first spring 402 pushes the support plate 4 back to its tilted locked state, stopping the lifting body 2 from descending.

[0049] It is worth noting that in the static state, the fine-tuning sleeve 7 abuts against the support plate 4. Since the fine-tuning sleeve 7 has an inclined surface 710 with the same slope as the support plate 4 in the static state, and the lower anti-rotation handle 720 is blocked and limited by the anti-rotation block 621, the force exerted by the second spring 702 on the fine-tuning sleeve 7 will act uniformly on the support plate 4 in a direction parallel to the axis of the lifting rod 1. As long as the support plate 4 maintains its inclined posture and the force acting on it does not have localized bias, the support plate 4 can maintain a stable frictional lock with the lifting rod 1. Therefore, the abutment of the fine-tuning sleeve 7 against the support plate 4 in the static state will not cause biased rotation of the support plate 4, and thus will not affect the frictional force between the support plate 4 and the lifting rod 1. Only when the down fine-tuning trigger 6 is squeezed will the limiting effect of the anti-rotation handle 720 on the anti-rotation block 621 be released, allowing the fine-tuning sleeve 7 to rotate. Furthermore, when the down fine-tuning trigger 6 is squeezed, it can also exert bias pressure on the support plate 4. At this time, the fine-tuning sleeve 7 and the support plate 4 will work together, allowing the fine-tuning sleeve 7 to replace the support plate 4 in locking with the lifting rod 1. In other cases, the rotation of the fine-tuning sleeve 7 is limited and will not cause friction with the lifting rod 1. For example, the design of the release lever 810 passing through the fifth through hole 620 of the down fine-tuning trigger 6 without interference is to prevent the down fine-tuning trigger 6 from being accidentally activated when the release trigger 8 is pressed. This avoids the fine-tuning sleeve 7 being driven when the release trigger 8 is pressed, ensuring that the fine-tuning sleeve 7 can only be released by the down fine-tuning trigger 6.

[0050] Through the above structural design and action coordination, this double-trigger ratchet lifting jack retains the foot-driven lifting and rapid release retraction functions of the existing technology, while also achieving precise retraction with a small stroke by adding a downward fine-tuning trigger 6. At the same time, the positions of each trigger are reasonably arranged, and there is no interference during operation, which meets the needs of operation scenarios with strict requirements for lifting height, and improves the practicality and safety of the jack.

[0051] The above description is merely a specific embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in this utility model, based on the technical solution and concept of this utility model, should be included within the protection scope of this utility model.

Claims

1. A double-trigger ratchet lifting jack, comprising a lifting lever, a lifting body sleeved on the lifting lever, a support base disposed at one end of the lifting lever, and a lifting plate disposed on the lifting body, characterized in that, Also includes: A fixing plate is installed inside the lifting main body cavity, which divides the lifting main body cavity into a lower cavity and an upper cavity; The fixed handle is located in the middle of one side of the lifting body; The drive trigger is located above the fixed handle and is connected to the lifting drive unit located in the upper cavity of the lifting body; The down-adjustment trigger is located below the fixed handle. One side of the down-adjustment trigger and one side of the adjustment sleeve are respectively hinged to the first pin. The first pin is located on the right side of the lifting rod. The adjustment sleeve is fitted on the lifting rod. The top side of the adjustment sleeve is connected to the fixed plate through the second spring fitted on the lifting rod. The down-adjustment trigger is provided with an anti-rotation block. The anti-rotation block is matched with the anti-rotation handle on the adjustment sleeve so that the adjustment sleeve is rotated and limited under the action of the rebound force of the second spring. Several support plates are sleeved on the lifting rod and located below the fine-tuning sleeve. One end of the support plate on the left side is connected to the support limiting part on the lifting body, and the lower part of the right end of the support plate is connected to the inner cavity of the lifting body through the first spring. The release trigger is located between the down fine-tuning trigger and the fixed handle. It is hinged to the lifting body via a second pin. A third pin is provided on one end of the left side of the release trigger. One end of the release lever is hinged to the third pin, and the other end passes through the down fine-tuning trigger and abuts against the support plate.

2. The double-trigger ratchet lifting jack as described in claim 1, characterized in that, The lifting drive unit includes: several drive plates, sleeved on the lifting rod and located in the upper cavity, with the top of one end on the left abutting and limiting the drive limiting part on the inner wall of the lifting body, and a third through hole in the middle for the lifting rod to pass through and conforming to the cross-section of the lifting rod; two third springs are respectively arranged on the left and right sides of the lifting rod in the upper cavity, with the two ends of the third springs abutting the top of the fixing plate and the bottom of the drive plate respectively; the drive plates are in frictional engagement with the lifting rod through the inner wall of the third through hole; The drive trigger is hinged to the trigger positioning cylinder fixed inside the lifting body in the middle. The right end of the drive trigger is provided with a drive handle extending from the drive through groove on the surface of the lifting body. The lower side of the middle part of the drive trigger is provided with a drive protrusion, which abuts against the top surface of the drive plate. The support plate and the drive plate are respectively positioned to be inclined to the lifting rod by the abutment of the first spring, the support limiting part, the third spring and the drive limiting part.

3. The double-trigger ratchet lifting jack as described in claim 1, characterized in that, The right end of the downward fine-tuning trigger has a fine-tuning handle that passes through the fine-tuning groove on the surface of the lifting body. The lower part of the left end, near the support plate, has a protruding pressure head that presses against the top of the right end of the support plate. The fine-tuning handle has a fifth through hole.

4. The double-trigger ratchet lifting jack as described in claim 1, characterized in that, The support plate has a second through hole in the middle for the lifting rod to pass through, which is similar in shape to the cross section of the lifting rod. The support plate is in frictional engagement with the lifting rod through the inner wall of the second through hole. The first spring applies a bias pressure to the support plate, which, in conjunction with the limiting position of the support limiting part, causes the support plate to tilt along the axial direction of the lifting rod. The tilted support plate is then locked to the lifting rod by friction through the second through hole.

5. A double-trigger ratchet lifting jack as described in claim 1, characterized in that, The fine-tuning sleeve is located in the lower cavity. The middle part has a fourth through hole that allows the lifting rod to pass through and is shaped like the cross section of the lifting rod. The lower part is hinged to the first pin through the first pivot hole. The lower part of the fine-tuning sleeve has an inclined surface that abuts against the top surface of the support plate. The second spring exerts a vertical thrust on the fine-tuning sleeve, which drives the fine-tuning sleeve to rotate around the first pin. The rotational motion is limited by the cooperation of the anti-rotation block and the anti-rotation handle. The thrust of the second spring on the fine-tuning sleeve and the rotational limitation of the anti-rotation block and the anti-rotation handle together constitute the fine-tuning sleeve's vertical non-deflection angle abutment against the support plate.

6. The double-trigger ratchet lifting jack as described in claim 1, characterized in that, In the release trigger, one end of the release rod is hinged to the third pin, and the other end abuts against the upper side of the support plate. The release rod passes through the fifth through hole set on the downward fine-tuning trigger to form a clearance. The right end of the release trigger is provided with a release handle extending from the release through groove on the surface of the lifting body.

7. A double-trigger ratchet lifting jack as described in claim 1, characterized in that, The end of the release rod that abuts against the upper side of the support plate moves synchronously with the rotation of the release trigger around the second pin, pushing the support plate to rotate around the support limiting part and releasing the clamping lock between the support plate and the lifting rod.

8. A double-trigger ratchet lifting jack as described in claim 1, characterized in that, The fixing plate is horizontally installed in the inner cavity of the lifting body, and the middle of the fixing plate has a first through hole for the lifting rod to pass through.

9. A double-trigger ratchet lifting jack as described in claim 1, characterized in that, The support plate and the drive plate are several metal plates arranged close together.

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