A hanging electric chain hoist

Abstract

The application discloses a hanging type endless chain electric hoist, which comprises a hanging chain, a fixed plate and a hoist body fixed on the fixed plate, one end of the hanging chain is fixedly connected to the fixed plate, the other end is connected to the hoist body, a hook assembly is hung on the hanging chain, a limiter assembly is fixedly connected to the hanging chain on the fixed plate connecting side, a weight sleeve capable of moving up and down relative to the hanging chain is sleeved on the hanging chain below the limiter assembly, the limiter assembly comprises a stop block assembly clamped on the hanging chain, a weight balance rod group rotatably connected to the stop block assembly, a weight limiting switch is arranged below the weight balance rod group, and a steel wire rope is connected between the weight balance rod group and the weight sleeve. The weight type limiting is used as the first stage limiting, the push plate type limiting is used as the second stage limiting, different protection modes can be combined, the limiter is arranged in a separable structure, and the safety is ensured when the hook reaches the limit position and the hook is limited.

Description

Technical Field

[0001] This invention relates to a suspended electric chain hoist, belonging to the field of lifting machinery technology. Background Technology

[0002] In applications where electric hoists use circular chain as the lifting rope, to prevent the hook from being lifted too high and colliding with the electric hoist, thus causing a complete accident, the usual practice is to install a limit switch on the crane's chain.

[0003] Due to its compact structure, its limit switch is often difficult to install, especially in the middle of the transmission. This can no longer meet the needs of automated positioning and the increasing emphasis on safety assurance, while also addressing increasingly diverse usage requirements. Moreover, the limit switch added in the middle sometimes becomes a new safety hazard. For example, at the moment the limit switch collides with the hook, although the motor will stop rotating due to the instantaneous resistance, due to inertia, there is a period of continuous stress on the chain between the motor stopping and the chain completely stopping. During this process, if the limit switch is a fixed structure, the chain is prone to breakage, leading to objects falling from heights. Summary of the Invention

[0004] The technical problem to be solved by this invention is to provide a suspended electric chain hoist that uses a weighted limit switch as the first stage of limit switching and a push plate limit switch as the second stage of limit switching, which can be combined with different protection modes. At the same time, the limit switch is set to a separable structure, which ensures that when the hook reaches the limit position, the limit switch can be separated to release the chain limit, allowing the chain to continue moving to compensate for the tension caused by inertia when the motor suddenly stops. This ensures safety while limiting the hook limit.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0006] A suspended electric chain hoist includes a chain, a fixed plate, and a hoist body fixed to the fixed plate. One end of the chain is fixedly connected to the fixed plate, and the other end is connected to the hoist body. A hook assembly is hung on the chain. A limit switch assembly is fixedly connected to the chain on the side connected to the fixed plate. A counterweight sleeve that can move up and down relative to the limit switch assembly is fitted on the chain below the limit switch assembly. The limit switch assembly includes a stop block assembly that is snapped onto the chain and a counterweight balance bar assembly that is rotatably connected to the stop block assembly. A counterweight limit switch is provided below the counterweight balance bar assembly. A wire rope connects the counterweight balance bar assembly and the counterweight sleeve.

[0007] The aforementioned suspended electric chain hoist is characterized in that: a limit push plate is provided at the bottom of the stop block assembly, the limit push plate is connected to the stop block assembly by four connecting rods, and each connecting rod is fitted with a compression spring; a push plate limit switch is provided on the side of the stop block assembly, which can be triggered by the upward movement of the limit push plate.

[0008] The aforementioned suspended electric chain hoist is characterized in that: a buffer spring fitted on the chain is also provided on the counterweight sleeve.

[0009] The aforementioned suspended electric chain hoist is characterized in that: the stop block assembly includes a first chain stop block and a second chain stop block, the opposite sides of the first chain stop block and the second chain stop block are provided with through grooves of the same shape along their length direction, the two through grooves are provided with protrusions of the same height that can be inserted into the chain socket of the hanging chain, the first chain stop block and the second chain stop block are connected by an overload linkage assembly, the overload linkage assembly includes a rod and a head, and the connection between the rod and the head is provided with an overload protection fracture groove.

[0010] The aforementioned suspended electric chain hoist is characterized in that: threaded holes are provided on both the front and rear sides of the first chain stop block; bolt holes corresponding to the number and position of the threaded holes are provided on the second chain stop block; the rod part includes a screw part and a shoulder part that can be screwed into the threaded holes; the overload protection fracture groove is provided at the connection between the head and the shoulder part; and the bolt holes include a first groove for accommodating the head part with successively smaller diameters, a second groove for allowing the shoulder part to move freely, and a third groove for allowing only the screw part to pass freely.

[0011] The aforementioned suspended electric chain hoist is characterized in that: the protrusion has an arc-shaped structure, and its curvature is consistent with the curvature of the surface of the chain.

[0012] The aforementioned suspended electric chain hoist is characterized in that: the cross-section of the counterweight balance bar assembly is a C-shaped structure, and its front and rear sides are rotatably connected to the second chain stop block through fixed pins; the end face of the counterweight balance bar assembly is located on the outer side of the second chain stop block; and the counterweight limit switch is located below the end face of the counterweight balance bar assembly.

[0013] The aforementioned suspended electric chain hoist is characterized in that: the ends of the front and rear sides of the counterweight balance bar assembly are inwardly bent arc-shaped structures.

[0014] The aforementioned suspended electric chain hoist is characterized in that: a torsion spring is provided on the fixed pin.

[0015] The beneficial effects of this invention are:

[0016] 1. A weighted limit switch consisting of a weighted sleeve and a weighted balance bar assembly is used as the first stage of the limit switch, and the limit position can be adjusted by changing the length of the wire rope connecting the two; a push plate limit switch is used as the second stage of the limit switch, which can be combined into different protection modes as needed.

[0017] 2. By setting the limit switch to a separable structure, it is ensured that when the hook reaches the set limit position, the limit switch can be separated to release the chain limit, allowing the chain to continue moving to compensate for the tension caused by inertia when the motor suddenly stops, thus ensuring safety while limiting the hook.

[0018] 3. By setting an overload protection fracture groove on the bolt assembly used to connect the two stop blocks, once the tension on the chain is too great, the bolt assembly can be separated at the overload protection fracture groove, thereby separating the two stop blocks and releasing the restriction on the chain. At the same time, through the special design of the bolt hole and the setting of a counterweight balance bar group on the second stop block, the bolt assembly can separate the two stop blocks after breaking at the overload protection fracture groove, allowing the chain to pass smoothly, while ensuring that the separated bolt assembly will not fall off the chain and cause a falling object from a height. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of a suspended electric chain hoist according to the present invention.

[0020] Figure 2 This is a schematic diagram of the structure of a hanging electric chain hoist of the present invention, showing the limiter and counterweight assembly connected to the chain.

[0021] Figure 3 This is a top view of a limiter for a suspended electric chain hoist according to the present invention;

[0022] Figure 4 This is a schematic diagram showing the disassembled first chain stop block and second chain stop block of the limiter of a hanging electric chain hoist according to the present invention.

[0023] Figure 5 This is a schematic diagram of the overload linkage assembly of the limiter of a suspended electric chain hoist according to the present invention.

[0024] Figure 6 This is a side view of the counterweight balance bar assembly of a suspended electric chain hoist according to the present invention;

[0025] Figure 7 This is a top view of the counterweight balance bar assembly of a suspended electric chain hoist according to the present invention. Implementation

[0026] The present invention will now be further described with reference to the accompanying drawings.

[0027] like Figures 1-7 As shown, a suspended electric chain hoist includes a chain 10, a fixing plate 20, and a hoist body 30 fixed on the fixing plate 20. One end of the chain is fixedly connected to the fixing plate 20, and the other end is connected to the hoist body 30. A hook assembly 40 is hung on the chain 10. A limiter assembly 70 is fixedly connected to the chain 10 on the side connected to the fixing plate 20. A counterweight sleeve 61 that can move up and down relative to the chain 10 is fitted on the chain below the limiter assembly 70. The limiter assembly 70 includes a stop block assembly that is snapped onto the chain and a counterweight balance bar assembly 74 that is rotatably connected to the stop block assembly. A counterweight limit switch 75 is provided below the counterweight balance bar assembly 74. A wire rope 63 is connected between the counterweight balance bar assembly 74 and the counterweight sleeve 61.

[0028] According to the limit position requirements, the limiter assembly 70 is fixed at a suitable position on the lifting chain 10. Then, according to the requirements of the weighted limit trigger, a steel wire rope 63 of appropriate length is selected, and the weighted sleeve 61 is fitted onto the lifting chain 10. The weighted sleeve 61 pulls the weighted balance bar assembly 74 away from the weighted limit switch 75. As the hook assembly 40 is gradually lifted to contact the weighted sleeve 61 and lifted, the tension of the weighted sleeve 61 on the weighted balance bar assembly 74 disappears, causing it to rotate relative to the stop block assembly of the limiter assembly 70 and triggering the weighted limit switch 75. The weighted limit switch 75 sends a signal to the motor, and the motor performs the corresponding action according to the settings, realizing the first stage of limit triggering.

[0029] The bottom of the stop block assembly is provided with a limit push plate 77, which is connected to the stop block assembly by four connecting rods 78, each of which is fitted with a compression spring. A push plate limit switch 76, triggered by the upward movement of the limit push plate 77, is provided on the side of the stop block assembly. By using compression springs to keep the limit push plate 77 always away from the push plate limit switch 76 when there is no counterweight sleeve 61, the limit push plate 77 effectively eliminates vibrations during chain movement, especially sudden impacts, and prevents the push plate limit switch 76 from being abnormally triggered.

[0030] When the hook assembly 40 continues to be raised until the counterweight sleeve 61 contacts the limit push plate 77, the compression spring is compressed, which in turn triggers the push plate limit switch 76, sending a signal to the motor. The motor then performs the corresponding action according to the settings, realizing the second stage of limit triggering.

[0031] Based on the trigger signals from two different locations, different protection modes can be combined as needed, such as first stage deceleration, second stage stop; first stage working positioning, second stage safety protection; first stage working motion stop protection, second stage power management protection; first stage alarm, second stage safety protection, etc.

[0032] The counterweight sleeve 61 is also provided with a buffer spring 62 fitted on the hanging chain 10. The counterweight sleeve 61 contacts the limit push plate 77 through the buffer spring 62, so that the triggering process is a flexible triggering process to avoid damage to the components.

[0033] The stop block assembly includes a first chain stop block 71 and a second chain stop block 72 that are fitted into the chain socket of the hanging chain 10. The opposite sides of the first chain stop block 71 and the second chain stop block 72 are provided with through grooves of the same shape along their length direction. The two through grooves are provided with protrusions 711 of the same height that can be fitted into the chain socket of the hanging chain 10. The first chain stop block 70 and the second chain stop block 72 are connected by an overload linkage assembly 73. The overload linkage assembly 73 includes a rod and a head 733, and an overload protection fracture groove 734 is provided at the connection between the rod and the head.

[0034] When the electric hoist's front limit switches are not triggered or the set handling measures are not taken after triggering, the hook assembly 40 continues to be raised until it contacts the limit switch assembly 70. At this time, the limit switch assembly 70 will generate a momentary resistance on the chain, causing the motor to overload and stop rotating. However, the motor still has a certain rotational inertia and continues to apply tension to the chain assembly 10, thereby causing the chain assembly 10 to generate outward squeezing force on the protrusions 711 of the two chain stop blocks. This causes the overload linkage assembly 73 to break from the overload protection fracture groove 734, and the limit switch releases the limit on the chain assembly 10, allowing the chain assembly 10 to continue to move upward a certain distance until the tension generated by the rotational inertia of the motor is compensated and then it stops. This avoids the risk of the chain assembly 10 breaking due to the rotational inertia of the motor and falling objects from a height due to the continuous limitation of the chain assembly 10 by the fixed limit switch.

[0035] The protrusion 711 has an arc-shaped structure, and its curvature is consistent with the curvature of the surface of the chain 10. This ensures that the first chain stop block 71 and the second chain stop block 72 are completely locked onto the chain after being locked by the overload linkage assembly 73. At the extreme position, it can better bear the chain thrust, so that the chain assembly 10 can break the overload linkage assembly 73 at the overload protection fracture groove 734 with a small thrust. This ensures that the force required for the protection fracture groove 734 to break is much smaller than the force required for the chain assembly 10 to break.

[0036] The first chain stop block 71 has threaded holes 712 on both its front and rear sides. The second chain stop block 72 has bolt holes 721 corresponding to the number and position of the threaded holes 712. The rod part includes a screw part 731 that can be screwed into the threaded holes 712 and a shoulder part 732. The overload protection fracture groove 734 is provided at the connection between the head 733 and the shoulder part 732. The bolt hole 721 includes a first groove 722 for accommodating the head 733 with successively smaller diameters, a second groove 723 for the shoulder part 732 to move freely, and a third groove 724 for the screw part 731 to pass through freely.

[0037] When the overload linkage assembly 73 breaks at the overload protection fracture groove 734, the first chain stop block 71 drives the screw part 731 and the shoulder part 732 to move outward relative to the second chain stop block 72. At this time, the shoulder part 732 moves outward in the second groove 723 and is blocked and limited at the third groove 724. That is, the length of the second groove 723 is the length of the separation between the first chain stop block 71 and the second chain stop block 72. This ensures that the chain can pass between the two and that the first chain stop block 71 and the second chain stop block 72 are still fitted on the chain and will not fall off.

[0038] The counterweight balance bar assembly 74 has a C-shaped cross-section, and its front and rear sides are rotatably connected to the second chain stop block 72 via a fixed pin 79. The end face of the counterweight balance bar assembly 74 is located on the outer side of the second chain stop block 72, and the counterweight limit switch 75 is located below the end face of the counterweight balance bar assembly 74.

[0039] Simultaneously, the end face of the counterweight balance bar assembly 74 on the outer side of the second chain stop block 72 is used to block the separated head 733, preventing it from falling from a height. Therefore, even if the limit switch breaks due to overload protection fracture groove 734, no parts will fall, avoiding the occurrence of falling objects from a height.

[0040] A torsion spring 80 is provided on the fixed pin 79 to ensure the stability of the counterweight balance bar assembly 74. It helps to eliminate vibrations during the movement of the chain, especially sudden impacts, and prevents the counterweight limit switch from being too sensitive and malfunctioning.

[0041] The ends of the front and rear sides of the counterweight balance bar assembly 74 are curved inwards, which allows the counterweight balance bar assembly 74 to be stably fixed outside the stop block assembly, forming an anti-over-tilting protection buckle, limiting the tilt angle of the counterweight balance bar assembly 74, and ensuring that the operation does not lose protection due to excessive tilt angle.

[0042] In summary, the suspended electric chain hoist provided by this invention uses a counterweight-type limit switch as the first stage of limit switching and a push plate-type limit switch as the second stage of limit switching, which can be combined with different protection modes. At the same time, the limit switch is set to a separable structure, which ensures that when the hook reaches the limit position, the limit switch can be separated to release the chain limit, allowing the chain to continue moving to compensate for the tension caused by inertia when the motor suddenly stops. This ensures safety while limiting the hook limit.

[0043] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A suspended electric chain hoist, comprising a chain (10), a fixing plate (20), and a hoist body (30) fixed on the fixing plate (20), wherein one end of the chain is fixedly connected to the fixing plate (20), and the other end is connected to the hoist body (30), and a hook assembly (40) is mounted on the chain (10), characterized in that: A limiter assembly (70) is fixedly connected to the chain (10) on the connecting side of the fixed plate (20). A counterweight sleeve (61) that can move up and down relative to the chain (10) below the limiter assembly (70) is fitted on the chain (10). The limiter assembly (70) includes a stop block assembly that is clamped on the chain and a counterweight balance bar assembly (74) that is rotatably connected to the stop block assembly. A counterweight limit switch (75) is provided below the counterweight balance bar assembly (74). A wire rope (63) is connected between the counterweight balance bar assembly (74) and the counterweight sleeve (61). The bottom of the stop block assembly is provided with a limit push plate (77), which is connected to the stop block assembly by four connecting rods (78). Each connecting rod (78) is fitted with a compression spring. The side of the stop block assembly is provided with a push plate limit switch (76) that can be triggered by the upward movement of the limit push plate (77). The counterweight sleeve (61) is also provided with a buffer spring (62) fitted on the hanging chain (10). The stop block assembly includes a first chain stop block (71) and a second chain stop block (72). The opposite sides of the first chain stop block (71) and the second chain stop block (72) are provided with through slots of the same shape along their length direction. The two through slots are provided with protrusions (711) of the same height that can be inserted into the chain socket of the hanging chain (10). The first chain stop block (71) and the second chain stop block (72) are connected by an overload linkage assembly (73). The overload linkage assembly (73) includes a rod and a head (733), and an overload protection fracture groove (734) is provided at the connection between the rod and the head. The first chain stop block (71) has threaded holes (712) on both the front and rear sides. The second chain stop block (72) has bolt holes (721) corresponding to the number and position of the threaded holes (712). The rod part includes a screw part (731) that can be screwed into the threaded hole (712) and a shoulder part (732). The overload protection fracture groove (734) is provided at the connection between the head (733) and the shoulder part (732). The bolt hole (721) includes a first groove (722) for accommodating the head (733) with the diameter decreasing sequentially, a second groove (723) for the shoulder part (732) to move freely, and a third groove (724) for the screw part (731) to pass through freely.

2. The suspended electric chain hoist according to claim 1, characterized in that: The protrusion (711) has an arc-shaped structure, and its curvature is consistent with the curvature of the surface of the hanging chain (10).

3. A suspended electric chain hoist according to claim 2, characterized in that: The counterweight balance bar assembly (74) has a C-shaped cross-section. Its front and rear sides are rotatably connected to the second chain stop block (72) via a fixed pin (79). The end face of the counterweight balance bar assembly (74) is located on the outer side of the second chain stop block (72). The counterweight limit switch (75) is located below the end face of the counterweight balance bar assembly (74).

4. A suspended electric chain hoist according to claim 3, characterized in that: The ends of the front and rear sides of the counterweight balance bar assembly (74) are curved structures that bend inward.

5. The suspended electric chain hoist according to claim 3, characterized in that: A torsion spring (80) is provided on the fixed pin (79).

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