CN110077985B

CN110077985B - Jack

Info

Publication number: CN110077985B
Application number: CN201910411503.0A
Authority: CN
Inventors: 曹勇
Original assignee: Hangzhou Fuyang Yonngfu Machine Co ltd
Current assignee: Hangzhou Fuyang Yonngfu Machine Co ltd
Priority date: 2019-05-17
Filing date: 2019-05-17
Publication date: 2020-08-28
Anticipated expiration: 2039-05-17
Also published as: CN110077985A

Abstract

The invention provides a jack, and belongs to the technical field of hoisting equipment. It has solved the problem that there is the potential safety hazard in current jack. This jack, including main jacking frame, main jacking frame includes main saddle, two main upper arms, two main articulated framves, two main underarms and main base, be connected with the operation screw rod on two main articulated framves, the jack still includes two assistance jacking frames, assist the jacking frame all including assisting the saddle, two assist the upper arms, two assist articulated framves, two assist the underarm and assist the base, it has the bracing piece of ability luffing motion to assist all to articulate on the articulated frame, two relative bracing piece free ends all articulate mutually with a locating plate on two assistance jacking frames, be equipped with on the locating plate when two assist the base keep away from relatively making two bracing piece levels can lock the locking piece of locating plate locking on main articulated frame. The jack is convenient to store and simultaneously ensures the safety in use.

Description

Jack

Technical Field

The invention belongs to the technical field of hoisting equipment, and relates to a jack.

Background

The jack is light and small hoisting equipment which takes a rigid jacking piece as a working device and jacks a heavy object in a small stroke through a top bracket or a bottom supporting claw, is mainly used in departments of factories, mines, transportation and the like as vehicle repair and other hoisting, supporting and the like, has a light, firm, flexible and reliable structure, can be carried and operated by one person, is various in types and comprises a hydraulic jack, a scissor jack and the like, wherein the scissor jack is also called a support jack, is light and fast to use, is a vehicle-mounted product in various domestic automobile factories, consists of an upper support rod and a lower support rod which are made of metal plates, and needs to be operated to jack a vehicle locally when the automobile needs to change tires.

Disclosure of Invention

The invention aims to solve the problems in the prior art and provides a jack which is convenient to store and ensures the safety in use.

The purpose of the invention can be realized by the following technical scheme: a jack comprises a main jacking frame, wherein the main jacking frame comprises a main saddle, two main upper arms, two main hinged frames, two main lower arms and a main base, the upper ends of the two main upper arms are hinged with the main saddle, the lower ends of the two main upper arms are hinged with the two main hinged frames respectively, the upper ends of the two main lower arms are hinged with the two main hinged frames respectively, the lower ends of the two main lower arms are hinged with the main base, the two main hinged frames are connected with operating screw rods capable of driving the two main hinged frames to synchronously and reversely move, the jack is characterized by further comprising two auxiliary jacking frames respectively positioned at two sides of the main jacking frame, each auxiliary jacking frame comprises an auxiliary saddle, two auxiliary upper arms, two auxiliary hinged frames, two auxiliary lower arms and an auxiliary base, the upper ends of the two auxiliary upper arms are hinged with the auxiliary saddle, the lower ends of the two auxiliary hinged frames are hinged with the two auxiliary hinged frames respectively, the upper ends of the two auxiliary lower arms are hinged with the two auxiliary hinged frames respectively, and the lower ends of, the main base and two are assisted and are connected with the connecting rod that can make two assist the synchronous reverse migration of base between the base, it has the bracing piece of ability luffing motion all to articulate on the assistance hinge frame, and two relative bracing piece free ends all articulate mutually with a locating plate on two assistance jacking framves, be equipped with on the locating plate when two assistance bases keep away from relatively making two bracing piece levels can lock the locking piece on main hinge frame with the locating plate locking.

When the jack is not used, the two auxiliary jacking frames are moved to enable the two auxiliary jacking frames to be respectively abutted against two sides of the main jacking frame, the supporting rod swings upwards to be in a vertical state, the whole jack is flat and convenient to store, when the jack is required to be used, the two auxiliary jacking frames are moved towards two sides and unfolded, the connecting rod can ensure that the two auxiliary jacking frames are symmetrically arranged relative to the main jacking frame, the supporting rod swings downwards along with the unfolding of the two auxiliary jacking frames until the supporting rod is in a horizontal state, the auxiliary jacking frames are unfolded in place under the limitation of the supporting rod, the positioning plate is locked on the main hinging frame through the locking piece, the operating screw rod is manually rotated, the operating screw rod can transfer the two main hinging frames to synchronously move close to each other so as to drive the main saddle to ascend, synchronously, the main hinging frame can drive the auxiliary hinging frames through the supporting rod to enable the auxiliary saddle hinging frames to synchronously move, namely the auxiliary jacking operation, only need rotate an operation screw rod just can make main jacking frame and two supplementary jacking frame synchronous jacking, convenient operation, and because two are assisted the base and be the multiple spot with main base and support subaerial, and main saddle and two are assisted the saddle and also form the multiple spot to the vehicle and support for the jacking is more stable, and the security is higher.

In the jack, two pairs of supporting rods are arranged between two opposite auxiliary hinged frames on the two auxiliary jacking frames, positioning plates are hinged between the free ends of the same pair of supporting rods, when the two auxiliary bases move relatively close to each other, one supporting rod on the auxiliary hinged frame swings upwards, the other supporting rod swings downwards, and when the two auxiliary bases move relatively far away from each other, the two positioning plates are locked on the main hinged frame when the supporting rods are horizontal. Because main articulated frame need be to assisting the great power of carrying of articulated frame transmission among the jacking process, and two pairs of bracing pieces symmetry sets up for the power of carrying transmission is more stable, and a pair of bracing piece upswing when the jack draws in simultaneously, another pair of bracing piece downswing wholly is the platykurtic, conveniently deposits.

In the jack, the locating plate is in a U-shaped plate shape, the free ends of the two supporting rods are respectively hinged to the inner sides of the two ends of the locating plate, the main hinge frame is fixedly provided with the locating block, the upper side surface and the lower side surface of the locating block are respectively provided with a clamping groove, when the supporting rods are horizontal, the two locating plates are respectively buckled on the upper side and the lower side of the locating block, and one side edge of each locating plate is clamped in the clamping groove. Two locating plates are buckled respectively in the upper and lower both sides of locating piece when two assist jacking framves expand for two locating plates are the symmetry setting, and the atress is more steady, and the locating plate is buckled in the draw-in groove simultaneously, and is connected more stably between the locating piece.

In foretell jack, the locking piece includes two knobs, the knob all has the double-screw bolt, two all have the lock pin on the interior bottom surface of locating plate, the through hole has all been seted up along the axial to the lock pin, and the through hole runs through the locating plate, two the double-screw bolt of knob rotates the through hole that passes two lock pins respectively, all seted up the lockhole on the upper and lower side of locating piece, the screw has been seted up on the bottom surface of lockhole, works as two lock pins peg graft respectively in two lockholes of locating piece during the bracing piece level, and the double-screw bolt of two knobs is spiro union respectively in two screws. The locking post can be pegged graft in the locking hole when the locating plate is detained on the locating piece, increase the joint strength between locating plate and the locating piece, avoid the locating plate deformation to appear, and the double-screw bolt on the knob can the spiro union in the screw hole, thereby avoid the locating plate to break away from the locating piece, the double-screw bolt is worn to establish in the through hole of locking post simultaneously, can receive the protection of locking post, consequently the double-screw bolt can not radial atress in operation process, thereby deformation or screw thread quilt are destroyed to avoid appearing.

In the jack, the two main hinged frames are in a U-shaped plate shape, the end parts of the main upper arm and the main lower arm are respectively hinged to the inner sides of the two ends of the main hinged frame, the positioning block is fixed on the outer side surface of the main hinged frame, the operation screw rod is rotatably connected to one main hinged frame, the inner side of the other main hinged frame is fixed with a nut, through holes are formed in the two positioning blocks and penetrate through the main hinged frame, and the two ends of the operation screw rod respectively penetrate through the through holes. The structure is more compact and stable.

In the jack, the auxiliary hinge frame is in an L-shaped plate shape, the end parts of the auxiliary upper arm and the auxiliary lower arm are respectively hinged at two ends of the inner side surface of the auxiliary hinge frame, a U-shaped plate-shaped connecting frame is fixed on the outer side surface of the auxiliary hinge frame, and the end parts of the two supporting rods are respectively hinged at the inner sides of two ends of the connecting frame. The auxiliary hinge frame is fixedly arranged with the connecting frame, so that the integral structural strength is higher.

In foretell jack, the cross section of assisting the upper arm and assisting the underarm all is the U-shaped, and two assist the auxiliary upper arm notch of jacking frame relative, two assist the auxiliary lower arm notch of jacking frame relative, two assist the auxiliary upper arm lock joints of jacking frame on main upper arm when two assist the base all to lean on with main base mutually, and two are assisted the border counterbalance of upper arm and lean on, two assist the auxiliary lower arm of jacking frame all lock joints on main underarm, and two are assisted the border counterbalance of underarm and lean on. When the two auxiliary jacking frames are folded, the main upper arm is hidden in the two auxiliary upper arms, and the main lower arm is hidden in the two auxiliary lower arms, so that the folded structure is more compact and convenient to store.

In foretell jack, it has the swing arm to articulate on the side on the supplementary upper arm of one of them supplementary jacking frame, the bayonet socket has been seted up to the free end of swing arm, has the card post on the supplementary upper arm of another supplementary jacking frame on the side, and the bayonet socket of swing arm can the joint on the card post when two supplementary bases all lean on mutually with main base. After the two auxiliary jacking frames are folded, the swing arm is rotated to enable the buckle at the free end of the swing arm to be buckled on the clamping column, so that the two auxiliary jacking frames are tensioned, and the compact and stable structure is ensured.

In foretell jack, the bottom surface of main base has the installation breach, the connecting rod has two, and the middle part cross arrangement of two connecting rods, two the crossing position of connecting rod rotates through the support column and connects at the installation breach middle part of main base, two the both ends of connecting rod all have the spliced pole, two seted up the spout along length direction on the medial surface of assistance base, the spread groove has been seted up along length direction on the spout bottom surface, two the both ends of connecting rod insert respectively in the spout of two assistance bases, and the spliced pole slides and pegs graft in the spread groove, the lower extreme of support column still is fixed with the supporting seat. Through the setting of two connecting rods for two assist the jacking frame and expand in step, and then be accurate when making locating plate and locating piece lock joint, also can make two assist the jacking frame and draw in step, convenient operation, support column and supporting seat can support the middle part of main saddle, guarantee structural stability.

In the jack, the outer side edge of the lower side surface of the auxiliary saddle is provided with a hinged plate, the end parts of the two auxiliary upper arms are respectively hinged at the two ends of the hinged plate, a reinforcing plate is fixed between the hinged plate and the lower side surface of the auxiliary saddle, and the reinforcing plate is positioned between the end parts of the two auxiliary upper arms. The reinforcing plate improves the structural strength of the auxiliary saddle.

Compared with the prior art, the jack has the following advantages:

1. because two are assisted the jacking frame and are leaned on respectively in the both sides of main jacking frame when not using, bracing piece upswing to vertical state this moment, whole jack is the platykurtic, conveniently deposits, and two are assisted the base and are the multiple spot with main base and support subaerial when using, and main saddle and two are assisted the saddle and also form the multiple spot to the vehicle and support for the jacking is more stable, and the security is higher.

2. Because only one operation screw rod is needed to be rotated in the operation process, the main jacking frame and the two auxiliary jacking frames can be synchronously jacked, and the operation is convenient.

3. Because the stud is arranged in the through hole of the locking column in a penetrating way during jacking operation and can be protected by the locking column, the stud cannot be stressed radially in the operation process, thereby avoiding deformation or damage to threads

Drawings

Fig. 1 is a schematic perspective view of the jack when the jack is unfolded.

Fig. 2 is a schematic perspective view of the jack when folded.

Fig. 3 is an enlarged view of a structure at a in fig. 1.

Figure 4 is a top view of the structure with the jack deployed.

Fig. 5 is a sectional view of the structure at B-B in fig. 4.

Fig. 6 is an enlarged view of the structure at C in fig. 5.

Fig. 7 is a cross-sectional view of the structure at D-D in fig. 4.

In the figure, 1, a main jacking frame; 11. a main saddle; 12. a main upper arm; 13. a main hinge frame; 131. a nut; 14. a main lower arm; 15. a main base; 151. installing a notch; 152. a support pillar; 153. a supporting seat; 2. auxiliary jacking frames; 21. an auxiliary saddle; 211. a hinge plate; 212. a reinforcing plate; 22. an auxiliary upper arm; 23. an auxiliary hinge frame; 231. a connecting frame; 24. auxiliary lower arms; 25. an auxiliary base; 251. a chute; 252. connecting grooves; 3. operating the screw; 31. an operation section; 311. a jack; 4. a connecting rod; 41. connecting columns; 5. a support bar; 51. positioning a plate; 52. a locking post; 521. a through hole; 6. positioning blocks; 61. a card slot; 62. a lock hole; 63. a screw hole; 64. a through hole; 7. a knob; 71. a stud; 8. swinging arms; 81. a bayonet; 9. and (5) clamping the column.

Detailed Description

The following are specific embodiments of the present invention and are further described with reference to the drawings, but the present invention is not limited to these embodiments.

As shown in fig. 1, 2 and 3, a jack comprises a main jacking frame 1, the main jacking frame 1 comprises a main saddle 11, two main upper arms 12, two main hinged frames 13, two main lower arms 14 and a main base 15, the upper ends of the two main upper arms 12 are hinged with the main saddle 11, the lower ends of the two main upper arms 12 are hinged with the two main hinged frames 13, the upper ends of the two main lower arms 14 are hinged with the two main hinged frames 13, the lower ends of the two main hinged frames are hinged with the main base 15, the two main hinged frames 13 are connected with operating screws 3 capable of driving the two main hinged frames 13 to synchronously and reversely move, the jack further comprises two auxiliary jacking frames 2 respectively positioned at two sides of the main jacking frame 1, each auxiliary jacking frame 2 comprises an auxiliary upper arm saddle 21, two auxiliary hinged frames 22, two auxiliary hinged frames 23, two auxiliary lower arms 24 and an auxiliary base 25, the upper ends of the two auxiliary upper arms 22 are hinged with the auxiliary saddle 21, the lower ends of the two auxiliary hinged frames 24 are hinged with the two auxiliary hinged frames 23, the lower extreme all articulates on assisting base 25, is connected with between main base 15 and the two assistance bases 25 and can makes two connecting rods 4 of assisting base 25 synchronous reverse motion, it has bracing piece 5 of ability luffing motion all to articulate on assisting articulated frame 23, and two 5 free ends of two relative bracing pieces on assisting jacking frame 2 all articulate mutually with a locating plate 51, are equipped with on locating plate 51 to assist base 25 when two and keep away from relatively making two bracing pieces 5 locking piece on main articulated frame 13 of locating plate 51 locking when the level. When the lifting jack is not used, the two auxiliary lifting frames 2 are moved to enable the two auxiliary lifting frames 2 to be respectively abutted against two sides of the main lifting frame 1, the supporting rod 5 swings upwards to be in a vertical state, the whole lifting jack is flat and convenient to store, when the lifting jack is required to be used, the two auxiliary lifting frames 2 are moved to two sides and unfolded, the connecting rod 4 can ensure that the two auxiliary lifting frames 2 are symmetrically arranged relative to the main lifting frame 1, the supporting rod 5 swings downwards along with the unfolding of the two auxiliary lifting frames 2 until the supporting rod 5 is in a horizontal state, the auxiliary lifting frames 2 are unfolded in place under the limitation of the supporting rod 5, the positioning plate 51 is locked on the main hinged frame 13 through the locking piece, the operating screw rod 3 is manually rotated, the operating screw rod 3 can drive the two main hinged frames 13 to synchronously move close to drive the main saddle 11 to ascend, and synchronously, the main hinged frame 13 can drive the auxiliary hinged frame 23 through, make and assist articulated frame 23 synchronous motion, assist saddle 21 synchronous motion promptly, realize the jacking operation of jack, only need rotate an operation screw rod 3 in operation process and just can make main jacking frame 1 and two assist jacking frame 2 synchronous jacking, convenient operation, and because two assist base 25 and main base 15 to be the multiple spot and support subaerial, and main saddle 11 and two assist saddle 21 also to form the multiple spot support to the vehicle, make the jacking more stable, the security is higher.

As shown in fig. 4, 5 and 6, two pairs of support rods 5 are arranged between two opposite auxiliary hinge frames 23 on two auxiliary jacking frames 2, and positioning plates 51 are hinged between the free ends of the same pair of support rods 5, when two auxiliary bases 25 move relatively close to each other, one support rod 5 on the auxiliary hinge frame 23 swings upwards, the other support rod 5 swings downwards, when two auxiliary bases 25 move relatively far away to enable the support rod 5 to be horizontal, the two positioning plates 51 are locked on the main hinge frame 13, because the main hinge frame 13 needs to transmit a large load to the auxiliary hinge frames 23 in the jacking process, and the two pairs of support rods 5 are symmetrically arranged, so that the load transmission is more stable, and meanwhile, when the jack is folded, one pair of support rods 5 swings upwards, the other pair of support rods 5 swings downwards, and the whole is flat, so that the jack is convenient to store. Locating plate 51 is the U-shaped platelike, the free ends of two bracing pieces 5 articulate respectively in the both ends inboard of locating plate 51, be fixed with locating piece 6 on the main articulated frame 13, draw-in groove 61 has all been seted up on the upper and lower side of locating piece 6, two locating plates 51 lock joint respectively in the upper and lower both sides of locating piece 6 when bracing piece 5 is horizontal, and a side border joint of locating plate 51 is in draw-in groove 61, two locating plates 51 are detained respectively in the upper and lower both sides of locating piece 6 when two assist 2 expandes of jacking framves, make two locating plates 51 be the symmetry setting, the atress is more steady, locating plate 51 is detained in draw-in groove 61 simultaneously, and the connection. The locking piece comprises two knobs 7, each knob 7 is provided with a stud 71, each inner bottom surface of each positioning plate 51 is provided with a locking column 52, each locking column 52 is provided with a through hole 521 along the axial direction, each through hole 521 penetrates through each positioning plate 51, the studs 71 of the two knobs 7 respectively rotate to penetrate through the through holes 521 of the two locking columns 52, the upper side surface and the lower side surface of each positioning block 6 are respectively provided with a locking hole 62, the bottom surface of each locking hole 62 is provided with a screw hole 63, when the supporting rod 5 is horizontal, the two locking columns 52 are respectively inserted into the two locking holes 62 of the positioning block 6, the studs 71 of the two knobs 7 are respectively screwed into the two screw holes 63, when the positioning plate 51 is buckled on the positioning block 6, the locking columns 52 can be inserted into the locking holes, the connecting strength between the positioning plates 51 and the positioning blocks 6 is increased, the deformation of the positioning plates 51 is avoided, and the studs 71 on, meanwhile, the stud 71 penetrates through the through hole 521 of the locking column 52 and can be protected by the locking column 52, so that the stud 71 cannot be radially stressed in the operation process, and deformation or thread damage is avoided.

Two main articulated framves 13 all are the U-shaped plate form, the tip of main upper arm 12 and main lower arm 14 articulates respectively at the both ends inboard of main articulated frame 13, locating piece 6 is fixed on the lateral surface of main articulated frame 13, operation screw rod 3 rotates on connecting a main articulated frame 13, the inboard of another main articulated frame 13 is fixed with nut 131, through-hole 64 has all been seted up on two locating pieces 6, and through-hole 64 runs through main articulated frame 13, through-hole 64 is passed respectively at the both ends of operation screw rod 3, the one end of keeping away from nut 131 at operation screw rod 3 has operation portion 31, offer on operation portion 31 and supply shaft handle male jack 311. The auxiliary hinge frame 23 is in an L-shaped plate shape, the end parts of the auxiliary upper arm 22 and the auxiliary lower arm 24 are respectively hinged to two ends of the inner side surface of the auxiliary hinge frame 23, a U-shaped plate-shaped connecting frame 231 is fixed on the outer side surface of the auxiliary hinge frame 23, the end parts of the two support rods 5 are respectively hinged to the inner sides of two ends of the connecting frame 231, and the auxiliary hinge frame 23 and the connecting frame 231 are fixedly arranged, so that the overall structural strength is higher. The cross sections of the auxiliary upper arms 22 and the auxiliary lower arms 24 are both U-shaped, notches of the auxiliary upper arms 22 of the two auxiliary jacking frames 2 are opposite, notches of the auxiliary lower arms 24 of the two auxiliary jacking frames 2 are opposite, when the two auxiliary bases 25 are abutted against the main base 15, the auxiliary upper arms 22 of the two auxiliary jacking frames 2 are buckled on the main upper arm 12, edges of the two auxiliary upper arms 22 are abutted against, the auxiliary lower arms 24 of the two auxiliary jacking frames 2 are buckled on the main lower arm 14, edges of the two auxiliary lower arms 24 are abutted against, when the two auxiliary jacking frames 2 are folded, the main upper arm 12 is hidden in the two auxiliary upper arms 22, and the main lower arm 14 is hidden in the two auxiliary lower arms 24, so that the folded structure is more compact and convenient to store. It has swing arm 8 to articulate on the side on the supplementary upper arm 22 of one of them supplementary jacking frame 2, bayonet socket 81 has been seted up to swing arm 8's free end, another supplementary jacking frame 2 has card post 9 on the supplementary upper arm 22 of side, bayonet socket 81 of swing arm 8 can the joint on calorie post 9 when two are assisted base 25 and all lean on with main base 15 counterbalance, rotate swing arm 8 after two supplementary jacking frames 2 draw in, the buckle lock joint that makes its free end is on calorie post 9, thereby it is taut with two supplementary jacking frames 2, guarantee compact structure and stability. The outer side edge of the lower side surface of the auxiliary saddle 21 is provided with a hinged plate 211, the end parts of the two auxiliary upper arms 22 are respectively hinged at two ends of the hinged plate 211, a reinforcing plate 212 is fixed between the hinged plate 211 and the lower side surface of the auxiliary saddle 21, the reinforcing plate 212 is positioned between the end parts of the two auxiliary upper arms 22, and the reinforcing plate 212 improves the structural strength of the auxiliary saddle 21. As shown in fig. 7, the bottom surface of the main base 15 has an installation notch 151, two connecting rods 4 are provided, the middle portions of the two connecting rods 4 are arranged in a crossed manner, the crossed positions of the two connecting rods 4 are rotatably connected to the middle portion of the installation notch 151 of the main base 15 through supporting pillars 152, connecting posts 41 are provided at two ends of the two connecting rods 4, two sliding grooves 251 are provided on the inner side surface of the auxiliary base 25 along the length direction, connecting grooves 252 are provided on the bottom surface of the sliding grooves 251 along the length direction, two ends of the two connecting rods 4 are respectively inserted into the sliding grooves 251 of the two auxiliary bases 25, the connecting posts 41 are slidably inserted into the connecting grooves 252, a supporting seat 153 is further fixed at the lower end of the connecting posts 41, the two auxiliary jacking frames 2 are synchronously unfolded through the arrangement of the two connecting rods 4, so that the positioning plate 51 is accurately fastened to the positioning block 6.

The specific embodiments described herein are merely illustrative of the spirit of the invention. Various modifications or additions may be made or substituted in a similar manner to the specific embodiment described by those skilled in the art without departing from the spirit of the invention or exceeding the scope thereof as defined in the annexed claims, although the terms main jacking frame 1, main saddle 11, main upper arm 12 and the like are used herein in greater detail, without excluding the possibility of using other terms.

Claims

1. The utility model provides a jack, includes main jacking frame (1), main jacking frame (1) is including main saddle (11), two main upper arms (12), two main articulated frame (13), two main lower arms (14) and main base (15), and the upper end of two main upper arms (12) all articulates with main saddle (11) mutually, and the lower extreme articulates with two main articulated frame (13) mutually respectively, and the upper end of two main lower arms (14) is articulated mutually with two main articulated frame (13) respectively, and the lower extreme all articulates on main base (15), two be connected with on main articulated frame (13) and can drive two main articulated frame (13) synchronous reverse movement's operating screw (3), its characterized in that, the jack still includes two auxiliary jacking frame (2) that are located main jacking frame (1) both sides respectively, auxiliary jacking frame (2) all include auxiliary saddle (21), two auxiliary upper arms (22), two auxiliary articulated frame (23), Two auxiliary lower arms (24) and an auxiliary base (25), the upper ends of the two auxiliary upper arms (22) are hinged with the auxiliary saddle (21), the lower ends are respectively hinged with the two auxiliary hinge frames (23), the upper ends of the two auxiliary lower arms (24) are respectively hinged with the two auxiliary hinge frames (23), the lower ends are respectively hinged on the auxiliary base (25), a connecting rod (4) which can lead the two auxiliary bases (25) to synchronously and reversely move is connected between the main base (15) and the two auxiliary bases (25), the auxiliary hinged frames (23) are hinged with support rods (5) capable of swinging up and down, the free ends of the two support rods (5) opposite to each other on the two auxiliary jacking frames (2) are hinged with a positioning plate (51), the positioning plate (51) is provided with a locking piece which can lock the positioning plate (51) on the main hinged frame (13) when the two auxiliary bases (25) are relatively far away to enable the two supporting rods (5) to be horizontal.

2. The jack according to claim 1, characterized in that two pairs of support rods (5) are arranged between two opposite auxiliary hinged frames (23) on the two auxiliary jacking frames (2), and positioning plates (51) are hinged between the free ends of the same pair of support rods (5), when the two auxiliary bases (25) move relatively close to each other, one support rod (5) on the auxiliary hinged frame (23) swings upwards, the other support rod (5) swings downwards, and when the two auxiliary bases (25) move relatively far away from each other, the two positioning plates (51) are locked on the main hinged frame (13) when the support rods (5) are horizontal.

3. The jack according to claim 2, wherein the positioning plate (51) is in a U-shaped plate shape, the free ends of the two support rods (5) are respectively hinged to the inner sides of the two ends of the positioning plate (51), the positioning block (6) is fixed on the main hinge frame (13), the upper side surface and the lower side surface of the positioning block (6) are respectively provided with a clamping groove (61), when the support rods (5) are horizontal, the two positioning plates (51) are respectively fastened on the upper side surface and the lower side surface of the positioning block (6), and one side edge of the positioning plate (51) is clamped in the clamping groove (61).

4. A jack as claimed in claim 3 in which the locking member comprises two knobs (7), the knobs (7) are provided with studs (71), the inner bottom surfaces of the two positioning plates (51) are provided with locking columns (52), the locking columns (52) are provided with through holes (521) along the axial direction, the through hole (521) penetrates through the positioning plate (51), the studs (71) of the two knobs (7) respectively rotate and penetrate through the through holes (521) of the two locking columns (52), the upper side surface and the lower side surface of the positioning block (6) are both provided with a lock hole (62), the bottom surface of the lock hole (62) is provided with a screw hole (63), when the supporting rod (5) is horizontal, the two locking columns (52) are respectively inserted into the two locking holes (62) of the positioning block (6), and the studs (71) of the two knobs (7) are respectively screwed in the two screw holes (63).

5. The jack according to claim 4, wherein the two main hinge frames (13) are both in a U-shaped plate shape, the ends of the main upper arm (12) and the main lower arm (14) are respectively hinged to the inner sides of the two ends of the main hinge frame (13), the positioning block (6) is fixed on the outer side surface of the main hinge frame (13), the operation screw (3) is rotatably connected to one main hinge frame (13), the inner side of the other main hinge frame (13) is fixedly provided with a nut (131), the two positioning blocks (6) are respectively provided with a through hole (64), the through holes (64) penetrate through the main hinge frame (13), and the two ends of the operation screw (3) respectively penetrate through the through holes (64).

6. The jack according to any one of claims 2 to 5, wherein the auxiliary hinge frame (23) is in the shape of an L, the ends of the auxiliary upper arm (22) and the auxiliary lower arm (24) are respectively hinged at two ends of the inner side surface of the auxiliary hinge frame (23), a U-shaped plate-shaped connecting frame (231) is fixed on the outer side surface of the auxiliary hinge frame (23), and the ends of the two support rods (5) are respectively hinged at the inner sides of two ends of the connecting frame (231).

7. The jack according to any one of claims 2 to 5, wherein the cross section of the auxiliary upper arm (22) and the auxiliary lower arm (24) is U-shaped, the notches of the auxiliary upper arms (22) of the two auxiliary jacking frames (2) are opposite, the notches of the auxiliary lower arms (24) of the two auxiliary jacking frames (2) are opposite, when the two auxiliary bases (25) are abutted against the main base (15), the auxiliary upper arms (22) of the two auxiliary jacking frames (2) are fastened on the main upper arm (12), the edges of the two auxiliary upper arms (22) are abutted, the auxiliary lower arms (24) of the two auxiliary jacking frames (2) are fastened on the main lower arm (14), and the edges of the two auxiliary lower arms (24) are abutted.

8. The jack according to claim 7, wherein the upper side surface of the auxiliary upper arm (22) of one of the auxiliary jacking frames (2) is hinged with a swing arm (8), the free end of the swing arm (8) is provided with a bayonet (81), the upper side surface of the auxiliary upper arm (22) of the other auxiliary jacking frame (2) is provided with a clamping column (9), and the bayonet (81) of the swing arm (8) can be clamped on the clamping column (9) when the two auxiliary bases (25) are abutted against the main base (15).

9. A jack as claimed in any one of claims 2 to 5 in which the main base (15) has mounting notches (151) in its underside and two of the links (4), the middle parts of the two connecting rods (4) are arranged in a crossed manner, the crossed positions of the two connecting rods (4) are rotatably connected to the middle part of the mounting gap (151) of the main base (15) through supporting columns (152), connecting columns (41) are arranged at two ends of the two connecting rods (4), sliding grooves (251) are formed in the inner side surfaces of the two auxiliary bases (25) along the length direction, the bottom surface of the sliding chute (251) is provided with a connecting groove (252) along the length direction, two ends of the two connecting rods (4) are respectively inserted into the sliding chutes (251) of the two auxiliary bases (25), and the connecting column (41) is inserted in the connecting groove (252) in a sliding manner, and the lower end of the supporting column (152) is also fixed with a supporting seat (153).

10. The jack according to any one of claims 2 to 5, wherein the outer side edge of the lower side surface of the auxiliary saddle (21) is provided with a hinged plate (211), the ends of the two auxiliary upper arms (22) are respectively hinged at two ends of the hinged plate (211), a reinforcing plate (212) is fixed between the hinged plate (211) and the lower side surface of the auxiliary saddle (21), and the reinforcing plate (212) is positioned between the ends of the two auxiliary upper arms (22).