CN217076901U - Lifting equipment with goods overweight detection function - Google Patents

Abstract

The utility model discloses a lifting means with overweight function that detects of goods increases the chain and is connected the module between chain and the platform frame that carries cargo, carries cargo the platform frame outside still be equipped with chain connecting block complex overload detection switch, can accurately realize the overweight detection of goods, whole module simple structure, the reliability is high, simple to operate, with low costs, easily realize, and install at chain hookup location, occupation space is little, does not influence the platform that carries cargo and carries transport face height. When the elevator is used independently as a single machine, the overweight detection function of the goods can be realized.

Description

Lifting equipment with cargo overweight detection function

Technical Field

The utility model belongs to the technical field of the lifting means technique and specifically relates to a lifting means with overweight detection function of goods.

Background

With the development of the logistics industry and the intelligent warehousing technology, the use of conveying equipment and lifting equipment is increasing. The reciprocating type tray elevator can be butted with an external conveyor, can also be used independently as single equipment, and can realize the transfer of tray goods among different heights. Reciprocating type tray lifting machine often adopts chain, wire rope or hold-in range etc. to hang the cargo bed, utilizes motor or pneumatic cylinder to provide power, drives the cargo bed and reciprocates. When the weight of goods entering the tray elevator exceeds the designed maximum load capacity of the elevator, the chain, the steel wire rope or the synchronous belt can be broken due to the fact that the load exceeds the allowable tensile load, the safe operation of equipment is affected, and even serious safety accidents are caused. Therefore, the weight of the goods entering the elevator needs to be detected, and the goods are prevented from being overloaded.

The existing scheme is that a weighing device (generally a pressure sensor) is added at the bottom of an external conveying module or a goods carrying table conveying module to weigh goods entering a lifting machine, so that the weight of the goods can be accurately measured, and the overweight goods are effectively prevented from entering the lifting machine. If only the weighing device is added to the external conveying device, the hoister loses the goods weighing function when being used independently as a stand-alone device. If install the module of weighing in the cargo bed bottom, because the module of weighing is bulky, occupy great installation space, increase the transport face height, reduced the commonality of equipment. Meanwhile, the price of the weighing equipment is higher, and the cost of the whole machine is improved.

In other current schemes, increase the spring between loading platform and promotion chain, the flexible volume through the spring under the different loads triggers safety switch, realizes the detection to overweight goods. However, in this scheme, after the load gets into the cargo bed, can lead to the cargo bed to sink or shake from top to bottom because of the spring is compressed, influence equipment stability, can reduce the life-span that promotes chain, transmission shaft or other structure spare moreover. If the spring with large rigidity coefficient is selected, the difference of the spring compression amount under different loads is small, the safety switch is difficult to adjust, and the risk of false triggering exists.

SUMMERY OF THE UTILITY MODEL

The utility model aims to solve the problems and provide a lifting device with the function of detecting the overweight of goods, which can accurately detect the overweight of goods, has simple structure and high reliability, is arranged at the connecting position of a chain, occupies small space and does not influence the height of the conveying surface of a goods-carrying platform; meanwhile, after normal goods enter the elevator, the goods carrying platform cannot sink or shake up and down due to the existence of the spring, and the stability of the equipment is ensured.

The utility model provides a technical scheme that its technical problem adopted is:

a lifting device with a cargo overweight detection function comprises a main body frame, a cargo carrying platform module and an upper frame module, wherein the cargo carrying platform module is arranged in the main body frame and can lift in the main body frame, the upper frame module is arranged at the upper end of the main body frame, a motor for driving the cargo carrying platform module to lift is arranged in the upper frame module, the cargo carrying platform module comprises a cargo carrying platform frame which is connected with the main body frame in a sliding mode and a roller conveying module arranged on the cargo carrying platform frame, the motor is connected with the cargo carrying platform frame through a chain, a chain connecting module is arranged between the chain and the cargo carrying platform frame, the chain connecting module comprises a support arranged on the outer side of the cargo carrying platform frame, a chain connecting block arranged at the lower end of the chain and a screw rod used for connecting the chain connecting block with the support, an overload detection switch matched with the chain connecting block is further arranged on the outer side of the cargo carrying platform frame, and a transverse plate is arranged on the support, the lower end of the screw rod penetrates through the transverse plates and is in sliding connection with the transverse plates, a compression spring is arranged between the lower end of the screw rod and the transverse plates, and the device further comprises a pre-tightening mechanism for pre-tightening the compression spring.

Further, the chain connecting block is the T shape of invering, and chain connecting block both ends all are equipped with the through-hole, and the screw rod upper end is passed the through-hole, the screw rod is located chain connecting block top and is equipped with coupling nut.

Furthermore, inclined planes matched with rollers at the end parts of the overload detection switches are arranged on two sides of the chain connecting block.

Further, the upper end of the screw rod is provided with a cotter pin.

Furthermore, the pre-tightening mechanism comprises a pre-tightening block arranged at the lower end of the screw rod and a pre-tightening nut arranged on the screw rod and positioned above the transverse plate.

Furthermore, the side plates used for guiding the chain connecting blocks and the pre-tightening blocks in the sliding direction are arranged at the two ends of the transverse plate on the support, and inclined plates inclined towards the outside are arranged at the two ends of each side plate.

Further, the chain breakage detection mechanism is further included.

Furthermore, the chain breakage detection mechanism comprises a chain breakage detection plate arranged on the chain connection block and a chain breakage detection switch arranged on the loading platform frame and matched with the chain breakage detection plate.

The utility model has the advantages that:

1. the utility model discloses increase the chain and connect the module between chain and the platform frame that carries cargo, carry cargo the platform frame outside still be equipped with chain connecting block complex overload detection switch, can accurately realize the overweight detection of goods, whole module simple structure, the reliability is high, simple to operate, with low costs, easily realize, and install at chain hookup location, occupation space is little, does not influence the platform transport surface height that carries cargo. When the elevator is used independently as a single machine, the overweight detection function of the goods can be realized.

2. The utility model discloses well chain connecting block both ends all are equipped with the through-hole, and the through-hole is passed to the screw rod upper end, and the screw rod is located chain connecting block top and is equipped with coupling nut, is connected with two screw rods simultaneously at a chain connecting block, has increased the reliability of connecting and the stability of chain connecting block.

3. The utility model discloses well pretension mechanism is including setting up the pretension piece and the pretension nut who sets up on the screw rod and lie in the diaphragm top at the screw rod lower extreme, according to the rated load of tray lifting machine, through pretension nut pretension compression spring, thus, when the cargo weight on carrying cargo bed module is less than the rated load, compression spring can not compress, only when the goods surpasses the rated load, the spring just can continue to be compressed, carried cargo bed to sink or rock after having avoided normally going up the goods, the stability of equipment has been ensured, the extension promotes the chain, the life of transmission shaft and other structures.

4. The utility model discloses lie in the diaphragm both ends on the support and all be equipped with the curb plate that is used for direction chain connecting block and pretension piece slip direction, the curb plate both ends are equipped with the swash plate to the outside slope, and the swash plate turns up, forms the opening of loudspeaker form. When the weight of goods exceeds the rated load or the conditions of chain breakage and chain loosening occur, the chain connecting block and the spring pre-tightening block move up and down between the two side plates relative to the chain connecting block bracket. The horn-shaped opening can play a role in guiding, and the phenomenon that the chain connecting block and the pre-tightening block interfere or are stuck with the side plate when moving to influence the overweight detection or chain breakage detection function is avoided.

5. The utility model discloses still include chain rupture detection mechanism. The chain breakage detection mechanism comprises a chain breakage detection plate arranged on the chain connection block and a chain breakage detection switch arranged on the cargo platform frame and matched with the chain breakage detection plate. Set up the broken chain pick-up plate on the chain connecting block and set up at the broken chain detection switch of platform frame that carries cargo, can effectively detect the chain abnormal conditions, improved the security of equipment use. Chain connection, overweight detection and chain breakage detection are all completed through the chain connecting block or parts arranged on the chain connecting block, so that the multifunctional chain detection device is multipurpose, the number of parts is reduced, and the cost of the whole machine is reduced.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a schematic structural view of the present invention;

FIG. 2 is a front view of the cargo bed module of the present invention;

FIG. 3 is an enlarged view of a portion A of FIG. 2;

FIG. 4 is a schematic view of the structure of the cargo bed module of the present invention;

FIG. 5 is a front view of the chain connecting module of the present invention;

FIG. 6 is a schematic view of the structure of the chain connecting block of the present invention;

FIG. 7 is a schematic view of the bracket structure of the present invention;

FIG. 8 is a schematic view of the normal state of the present invention;

FIG. 9 is an enlarged view of a portion of FIG. 8 at B;

fig. 10 is a schematic view of the overload state of the present invention;

FIG. 11 is an enlarged view of a portion of FIG. 10 at C;

FIG. 12 is a schematic view of the chain breakage state of the present invention;

in the figure: main body frame 1, cargo bed module 2, cargo bed frame 201, roller table transport module 202, go up frame module 3, motor 4, chain 5, support 6, chain connecting block 7, screw rod 8, diaphragm 9, compression spring 10, overload detection switch 11, through-hole 12, coupling nut 13, inclined plane 14, split pin 15, pretension piece 16, pretension nut 17, curb plate 18, swash plate 19, broken chain detection board 20, broken chain detection switch 21.

Detailed Description

In order to make the technical solutions in the present invention better understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, but not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts shall belong to the protection scope of the present invention.

For convenience of description, a coordinate system is now defined as shown in fig. 1.

As shown in fig. 1 to 5, a lifting device with a cargo overload detection function comprises a main body frame 1, a cargo platform module 2 arranged in the main body frame 1 and lifting in the main body frame 1, and an upper frame module 3 arranged at the upper end of the main body frame 1, wherein the main body frame is used for supporting the whole structure, a motor 4 for driving the cargo platform module 2 to lift is arranged in the upper frame module 3, the upper frame module is fixedly arranged at the top of the main body frame, the cargo platform module 2 comprises a cargo platform frame 201 connected with the main body frame 1 in a sliding manner and a roller conveying module 202 arranged on the cargo platform frame 201, the roller conveying module 202 can adopt a roller conveying module or a chain conveying module without limitation and is used for conveying cargoes in and out of the lifting machine in a horizontal direction, guide rails are arranged on two sides of the main body frame 1, guide wheels matched with the guide rails are arranged on two ends of the cargo platform frame 201, when the cargo carrying platform frame 201 is lifted, the guide wheels slide up and down along the guide rails to guide the cargo carrying platform module to move up and down, the motor 4 drives the chains 5 to rotate to lift the cargo carrying platform frame 201, in this embodiment, four chains are provided, the cargo carrying platform frame 201 is suspended at one end of the four chains, the counterweight module is suspended at the other end of the chains 5 to balance the weight of the cargo carrying platform module and a part of the cargo, and reduce the power consumption of the lifting deceleration motor, a transmission shaft and power transmission parts are further provided in the upper frame module 3, the motor 4 drives the four chains to synchronously lift the cargo carrying platform frame 201 through the transmission shaft and the power transmission parts, so as to realize the stable lifting of the cargo carrying platform frame 201, which is the prior art and not described in more detail, chain connection modules are provided between the chains 5 and the cargo carrying platform frame 201, namely four chain connection modules are provided, the chain connecting module comprises a bracket 6 arranged outside a cargo platform frame 201, a chain connecting block 7 arranged at the lower end of the chain 5, and a screw 8 used for connecting the chain connecting block 7 with the bracket 6, the bracket 6 is fixed outside the cargo platform frame 201 through a bolt, an overload detection switch 11 matched with the chain connecting block 7 is also arranged outside the cargo platform frame 201, the overload detection switch 11 can adopt a travel switch and is fixedly arranged on the cargo platform frame 201 through the overload detection switch bracket, a long hole is arranged on the overload detection switch bracket, so that the travel switch can be conveniently adjusted in position in the up-down direction and the left-right direction, a transverse plate 9 is arranged on the bracket 6, and the lower end of the screw 8 penetrates through the transverse plate 9 and is connected between the transverse plates 9 in a sliding manner, a compression spring 10 is arranged between the lower end of the screw rod 8 and the transverse plate 9, and the device further comprises a pre-tightening mechanism for pre-tightening the compression spring 10.

The chain 5 with increase chain connection module between the platform frame 201 of carrying cargo, carry cargo the platform frame 201 outside still be equipped with the overweight detection switch 11 of chain connecting block 7 complex, can accurately realize the overweight detection of goods, whole module simple structure, the reliability is high, simple to operate, with low costs, easily realization, and install in chain hookup location, occupation space is little, does not influence the platform transport surface height of carrying cargo. When the elevator is used independently as a single machine, the overweight detection function of the goods can be realized.

As shown in fig. 5 and 6, chain connecting block 7 is the T shape of invering, and 7 both ends of chain connecting block all are equipped with through-hole 12, and pass on the screw rod 8 through-hole 12, screw rod 8 are located 7 tops of chain connecting block and are equipped with coupling nut 13, and screw rod 8 passes the through-hole of chain connecting block both sides to utilize coupling nut 13 to fix, top chain connecting hole and promotion chain round pin axle cooperation in the middle of 7 chain connecting blocks for the connection of chain connecting block and promotion chain. The upper and lower connecting positions are rounded, so that the stress concentration at the positions can be reduced, and the strength of the chain connecting block 7 is ensured. A chain connecting block is connected with two chain connecting screw rods simultaneously, and both screw rod 8 is equipped with two, and two 8 symmetries of screw rod set up, can reduce the atress on the every screw rod, under the same material, can reduce chain connecting screw rod's specification, have increased the reliability of connecting on the one hand, and on the other hand can improve the stability of chain connecting block, avoids rocking at business turn over goods in-process chain connecting block, leads to chain rupture detection switch to be triggered by mistake.

As shown in fig. 6, two sides of the chain connecting block 7 are provided with inclined surfaces 14 matched with rollers at the end of the overload detection switch 11. The gyro wheel of overload detection switch 11 tip contacts with the inclined plane of chain connecting block 7, when chain connecting block 7 relatively overloads detection switch 11 and when upwards moving, can promote the gyro wheel of overload detection switch 11 through the inclined plane, and then triggers overload detection switch 11, and overload detection device and chain connection module accomplish tray lifting machine overload detection function jointly.

As shown in fig. 5, the upper end of the screw 8 is provided with a cotter 15 for preventing the nut from loosening.

As shown in fig. 5, the pre-tightening mechanism comprises a pre-tightening block 16 arranged at the lower end of the screw rod 8 and a pre-tightening nut 17 arranged on the screw rod 8 and above the transverse plate 9, a limiting head is arranged at the lower end of the screw rod 8, the lower surface of the pre-tightening block 16 is in contact with the limiting head, and when the pre-tightening block 16 is installed, the pre-tightening block 16 penetrates through the screw rod 8 from top to bottom. The transverse plate 9 is provided with a through hole for penetrating through the chain to connect the screw rod, the diameter of the through hole is smaller than the outer diameter of the compression spring 10, and the pre-tightening nut 17 is screwed to compress the compression spring 10.

Assuming that the rated load designed by the pallet elevator is M, a load or a debugging weight with the mass of M can be placed on the cargo bed module in the debugging stage, the compression spring 10 is compressed under the action of the load M, and the elastic force of the compressed spring is F. At this time, the pre-tightening nut 17 above the transverse plate 9 can be screwed to the transverse plate 9, and after the load is removed, the compression spring 10 still keeps a compressed state under the action of the pre-tightening nut 17. Like this, when the goods weight on the platform module 2 of carrying cargo is less than rated load, compression spring 10 can not compress, and only when the goods surpassed rated load, the spring just can continue to be compressed, has avoided carrying cargo bed to sink or rock after normally going up the goods, has ensured the stability of equipment, prolongs the life who promotes chain, transmission shaft and other structures.

As shown in fig. 5 and 7, the bracket 6 is provided with side plates 18 at both ends of the transverse plate 9 for guiding the sliding direction of the chain connecting block 7 and the pre-tightening block 16, the side plates 18 are provided with inclined plates 19 inclined to the outside at both ends, the outside is the side far away from the chain connecting block 7 and the pre-tightening block 16, and the inclined plates 19 are turned outwards to form a trumpet-shaped opening. When the weight of the goods exceeds the rated load or chain breaking and loosening conditions occur, the chain connecting block and the spring pre-tightening block move up and down between the two side plates 18 relative to the chain connecting block bracket. The horn-shaped opening can play a role in guiding, and the phenomenon that the chain connecting block 7 and the pre-tightening block 16 interfere or are clamped with the side plate 18 when moving to influence the overweight detection or chain breakage detection function is avoided.

As shown in fig. 2 and 3, the chain breakage detection mechanism is further included. The chain breakage detection mechanism comprises a chain breakage detection plate 20 arranged on the chain connecting block 7 and a chain breakage detection switch 21 which is arranged on the cargo carrying platform frame 201 and matched with the chain breakage detection plate 20. The side of the chain connecting block 7 is provided with a threaded hole for installing the broken chain detecting plate 20, and the broken chain detecting switch 21 is fixedly installed on the cargo table frame 201 through a proximity switch bracket.

Two sides of the chain breakage detection plate 20 respectively extend outwards to form trigger plates for triggering the chain breakage detection switch 21. In the normal working process of the device, the chain connecting block 7 and the loading platform frame 201 are kept relatively static, the trigger plate of the broken chain detection plate 20 is positioned above the broken chain detection switch 21, the distance between the broken chain detection plate and the broken chain detection switch 21 cannot be changed, and the switch cannot be triggered. When the chain appears not hard up and can break, the chain disappears to the pulling force of chain connecting block 7, only receives self gravity. Because the hole that 7 both sides of chain connecting block are used for passing the screw rod is the through-hole, consequently the chain connecting block downstream under the action of gravity, and then drives the disconnected chain pick-up plate downstream. At this time, the trigger plate on the broken chain detection plate can shield the broken chain detection switch, so as to trigger the switch, as shown in fig. 12. After the system receives a signal that the chain breakage detection switch is triggered, the chain loosening or breaking can be judged, the equipment stops running, and an alarm is given, so that the chain breakage or chain loosening detection function is realized.

The chain breakage detection plate 20 and the chain breakage detection switch 21 arranged on the cargo table frame 201 are arranged on the chain connection block 7, so that chain abnormity can be effectively detected, and the use safety of the equipment is improved.

Chain connection, overweight detection and chain breakage detection are all completed through the chain connecting block or parts installed on the chain connecting block, so that the multifunctional chain detection device is multifunctional, the number of parts is reduced, and the cost of the whole machine is reduced.

Assume that the pallet lift design is rated at load M. In the debugging stage, a load with the mass of M or a debugging weight can be placed on the cargo platform module. The chain 5, the chain connecting block 7, the screw 8 and the pre-tensioning block 16 remain stationary. The pressure of the load to which the cargo bed module is subjected is transmitted to the compression springs 10 through the cargo bed frame 201 and the brackets 6. The compression spring 10 is compressed by a load M, and the spring force is F after the compression. At this time, the pre-tightening nut 17 above the transverse plate 9 can be screwed to the transverse plate 9, and after the load is removed, the compression spring 10 still keeps a compressed state under the action of the pre-tightening nut 17. Then, the position of the overload detection switch 11 relative to the cargo bed frame 201 is adjusted to make the roller of the overload detection switch 11 contact with the inclined surface 14 of the chain connecting block 7, so as to ensure that the overload detection switch 11 can be triggered smoothly, as shown in fig. 8 and 9.

When the weight of the cargo is less than the rated load M during the use of the device, the pressure on the compression spring 10 is less than the pressure generated by the rated load M. Since the compression spring 10 is already pre-tensioned by the load M, the compression spring 10 is subjected to a pressure less than F after the load enters the hoisting machine, and the compression spring 10 is not further compressed. The relative positions of the pre-tightening block 16, the screw 8, the chain connecting block 7 and the overload detection switch 11 are kept unchanged. The overload detection switch 11 is not triggered as shown in fig. 9. Under the effect of compression spring 10, after the goods that are less than rated load M got into the lifting machine, the goods platform module of carrying can not sink or rock because of the existence of compression spring 10, has guaranteed the stability of complete machine. When the weight of the cargo exceeds the rated load M, the pressure applied to the compression spring 10 is greater than the pressure generated by the rated load M, that is, the compression spring 10 is subjected to a pressure exceeding F, and at this time, the compression spring 10 is further compressed on the basis of the pretension. When the compression amount of the compression spring 10 increases, the chain connecting block 7 moves upward relative to the cargo bed frame 201. The slope 14 of the roller chain connecting block 7 of the overload detection switch 11 moves rightward, which causes the slope 14 to be triggered, as shown in fig. 10 and 11. After the system receives the signal that the inclined plane 14 is triggered, the overweight of the goods can be judged, the equipment stops running, and an alarm is given, so that the overweight detection function of the goods is realized.

It should be noted that the above-mentioned solution may also adopt the following alternative solution, in which the weight of the cargo is detected by using the tension sensor. Each lifting chain is cut into two sections, the end parts of each lifting chain are respectively connected with a screw rod, and then the screw rods are connected with a tension sensor. After the goods got into the tray lifting machine, the goods exerted pressure to carrying cargo bed, leads to the chain pulling force increase. Because the tension sensor is connected between the two sections of chains, the tension of the chains can be measured in real time. Through the processing of four tension sensor signals, the weight of the goods can be obtained. When the weight of the goods exceeds the rated load, the equipment stops running and gives an alarm, so that the weight of the goods is detected.

This scheme overload detection module need not increase spring, pretension part, detection switch etc. and the part is small in quantity, simple structure, simple to operate, easily debugging.

In the description of the present invention, it should be noted that the terms "left", "right", "upper", "lower", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplification of description, but do not indicate or imply that the device or element referred to must have a specific orientation, be constructed in a specific orientation, and be operated, and thus should not be construed as limiting the present invention.

In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; they may be mechanically or electrically connected, directly or indirectly through intervening media, or may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood in specific cases to those skilled in the art.

Claims (8)

1. The utility model provides a lifting means with goods overweight detection function, includes main body frame (1), sets up in main body frame (1) and carry cargo bed module (2) and set up upper ledge module (3) in main body frame (1) upper end that go up and down in main body frame (1), be equipped with motor (4) that the drive carried cargo bed module (2) and go up and down in upper ledge module (3), carry cargo bed module (2) including with main body frame (1) between sliding connection carry cargo bed frame (201) and set up roller table transport module (202) on carrying cargo bed frame (201), motor (4) are connected with carrying cargo bed frame (201) through chain (5), its characterized in that, chain (5) with be equipped with the chain between carrying cargo bed frame (201) and connect the module, the chain is connected the module including installing support (6) in the platform frame (201) outside, The cargo table frame is characterized by comprising chain connecting blocks (7) arranged at the lower end of a chain (5), and screw rods (8) used for connecting the chain connecting blocks (7) with a support (6), wherein overload detection switches (11) matched with the chain connecting blocks (7) are further arranged on the outer side of the cargo table frame (201), transverse plates (9) are arranged on the support (6), the lower ends of the screw rods (8) penetrate through the transverse plates (9) and are connected between the transverse plates (9) in a sliding mode, compression springs (10) are arranged between the lower ends of the screw rods (8) and the transverse plates (9), and the cargo table frame further comprises a pre-tightening mechanism used for pre-tightening the compression springs (10).

2. The lifting apparatus with the cargo overweight detection function according to claim 1, characterized in that the chain connecting block (7) is in an inverted T shape, through holes (12) are arranged at both ends of the chain connecting block (7), the upper end of the screw rod (8) passes through the through holes (12), and the screw rod (8) is provided with a connecting nut (13) above the chain connecting block (7).

3. The lifting apparatus with cargo overweight detection function of claim 1 characterized in that the two sides of the chain connecting block (7) are provided with inclined planes (14) which are matched with the rollers at the end of the overload detection switch (11).

4. A lifting device with cargo overweight detection function according to claim 1 characterized in that the upper end of the screw (8) is provided with a cotter pin (15).

5. The lifting apparatus with the cargo overweight detection function according to claim 1, characterized in that the pretensioning mechanism comprises a pretensioning block (16) arranged at the lower end of the screw rod (8) and a pretensioning nut (17) arranged on the screw rod (8) above the cross plate (9).

6. The lifting apparatus with the cargo overweight detection function according to claim 1, characterized in that the brackets (6) are provided with side plates (18) at both ends of the cross plate (9) for guiding the sliding direction of the chain connecting block (7) and the pretensioning block (16), and both ends of the side plates (18) are provided with inclined plates (19) inclining outwards.

7. A lifting device with cargo overweight detection function as claimed in claim 1, characterized by further comprising a chain-breaking detection mechanism.

8. A lifting device with an overweight detection of cargo according to claim 7 characterized in that the chain breakage detection mechanism comprises a chain breakage detection plate (20) mounted on the chain connecting block (7) and a chain breakage detection switch (21) mounted on the loading platform frame (201) and cooperating with the chain breakage detection plate (20).

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