Load limiting device of chain block

Abstract

The utility model provides a chain block load limiting device which is characterized in that the chain block load limiting device comprises a pressure regulating nut, a belleville spring, a pressing plate and a brake disc, the brake disc is connected with a hand chain wheel through the pressure regulating nut, the belleville spring and the pressing plate are arranged on the brake disc in a sleeved mode, and the pressure regulating nut, the belleville spring, the pressing plate and the hand chain wheel are sequentially arranged. A plurality of steel balls are installed on the hand chain wheel and evenly distributed, a plurality of arc pits matched with the steel balls are formed in the brake disc, a plurality of check pawls are further rotationally installed on the brake disc, and cylindrical springs are arranged between the check pawls and the brake disc. The non-return pawl is arranged in an inclined mode under the elastic force effect of the cylindrical spring, an arc waist groove matched with the non-return pawl is formed in the hand chain wheel, and the arc waist groove is an inclined face groove.

Description

Technical Field

[0001] The utility model belongs to the technical field of hand chain hoists and relates to a load limiting device for a hand chain hoist. Background Art

[0002] The load limiter on a conventional chain hoist consists of a pressure-adjusting nut, butterfly spring, pressure plate, friction plate A, hand chain pulley, friction plate B, and a brake disc. The device is configured to operate according to the set load limit, or slip point. Adjusting the pressure-adjusting nut secures the butterfly spring and presses the pressure plate, friction plate A, hand chain pulley, and friction plate B against the brake disc, forming two friction pairs that generate a load-limiting friction torque. When lifting a heavy object, pulling the hand chain rotates the hand chain pulley. If the load exceeds the load limit, the hand torque exceeds the load-limiting friction torque, causing the hand chain pulley to slip, signaling an overload. Manual hoists basically adopt the load limiting principle of friction and slippage. However, the load limiting device using this principle has the problem that the friction plate will be thermally attenuated during use, resulting in a decrease in the load limit value, or even lower than the rated load; and the stability of the load limiting friction torque is greatly affected by the surface quality of the parts processing, and the load limit value often fluctuates. The fluctuating load limit value will also cause the manual hoist to be unable to lower the heavy object after the heavy object is lifted into the air and slips. Therefore, it is very necessary to design a load limiting device for a hand hoist. Summary of the Invention

[0003] The purpose of the utility model is to solve the above problems in the existing technology and to propose a load limiting device for a hand chain hoist.

[0004] The purpose of the utility model can be achieved through the following technical solutions: a hand chain hoist load limiting device, characterized in that it includes a pressure-adjusting nut, a butterfly spring, a pressure plate and a brake disc, the brake disc is connected to the hand chain wheel through the pressure-adjusting nut, the butterfly spring and the pressure plate are sleeved on the brake disc, and the pressure-adjusting nut, butterfly spring, pressure plate and hand chain wheel are arranged in sequence, a number of steel balls are installed on the hand chain wheel, and the steel balls are evenly distributed, a number of arc pits matching the steel balls are provided on the brake disc, and a number of non-return pawls are also rotatably installed on the brake disc, a columnar spring is provided between the non-return pawl and the brake disc, and the non-return pawl is arranged obliquely under the elastic force of the columnar spring, and a circular arc waist groove matching the non-return pawl is provided on the hand chain wheel, and the circular arc waist groove is a bevel groove.

[0005] The pressure regulating nut is also threadedly connected with a set screw.

[0006] Both sides of the non-return pawl are provided with mounting shafts, and one end of the non-return pawl is provided with a placement groove for placing a cylindrical spring.

[0007] The hand chain wheel is also provided with a round hole matched with the steel ball.

[0008] The brake disc is also provided with a mounting groove for mounting a non-return pawl.

[0009] Compared with the existing technology, this hand chain hoist load limiting device has the following advantages:

[0010] 1. The original friction plate and friction structure are abandoned and replaced with a new friction pair consisting of a pressure regulating nut, butterfly spring, pressure plate, steel ball, and brake disc. This avoids the shortcomings of traditional friction plates such as thermal attenuation and the influence of friction torque on the surface processing quality of parts;

[0011] 2. The newly added non-return pawl effectively avoids the situation where the heavy object cannot be lowered due to the action of the load limit device after it is lifted;

[0012] 3. Effectively shorten the time for debugging the load limit value of the load limit device; BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a three-dimensional structural diagram of the utility model;

[0014] Figure 2 It is an explosion diagram of the utility model;

[0015] Figure 3 This is a schematic diagram of the three-dimensional structure of the brake disc in the utility model;

[0016] Figure 4 This is a schematic diagram of the three-dimensional structure of the stop pawl of the utility model;

[0017] Figure 5 This is a schematic diagram of the three-dimensional structure of the hand chain wheel in the utility model;

[0018] In the figure, 1. set screw; 2. pressure-adjusting nut; 3. butterfly spring; 4. pressure plate; 5. hand chain wheel; 5a. arc waist groove; 5b. round hole; 6. steel ball; 7. check pawl; 7a. mounting shaft; 7b. placement groove; 8. cylindrical spring; 9. brake disc; 9a. arc pit; 9b. mounting groove. DETAILED DESCRIPTION

[0019] The following are specific embodiments of the present invention and the accompanying drawings to further describe the technical solution of the present invention, but the present invention is not limited to these embodiments.

[0020] like Figure 1-Figure 5As shown, the load limiting device of the hand chain hoist includes a pressure-adjusting nut 2, a butterfly spring 3, a pressure plate 4 and a brake disc 9. The brake disc 9 is connected to the hand chain wheel 5 through the pressure-adjusting nut 2. The butterfly spring 3 and the pressure plate 4 are sleeved on the brake disc 9, and the pressure-adjusting nut 2, the butterfly spring 3, the pressure plate 4 and the hand chain wheel 5 are arranged in sequence. A plurality of steel balls 6 are installed on the hand chain wheel 5. In this embodiment, the number of steel balls 6 is six; and the steel balls 6 are evenly distributed. The brake disc 9 is provided with a plurality of arc recesses that match the steel balls 6. Pit 9a, in this embodiment, the number of the arc pits 9a is six; a number of non-return pawls 7 are also rotatably mounted on the brake disc 9, in this embodiment, the number of the non-return pawls 7 is three; a cylindrical spring 8 is provided between the non-return pawl 7 and the brake disc 9, and under the elastic force of the cylindrical spring 8, the non-return pawl 7 is arranged at an angle, and an arc waist groove 5a is provided on the hand chain wheel 5 to match the non-return pawl 7, in this embodiment, the number of the arc waist groove 5a is three; the arc waist groove 5a is a bevel groove.

[0021] The pressure regulating nut 2 is also threadedly connected with a set screw 1 .

[0022] Both sides of the non-return pawl 7 are provided with mounting shafts 7 a , and one end of the non-return pawl 7 is provided with a placement groove 7 b for placing the cylindrical spring 8 .

[0023] The hand chain wheel 5 also has a circular hole 5b that matches the steel ball 6.

[0024] The brake disc 9 also has a mounting groove 9 b for mounting the non-return pawl 7 .

[0025] Description of the load limiting working principle: This load limiting device relies on the pressure-adjusting nut 2 to compress and fix the butterfly spring 3, pressure plate 4, hand chain wheel 5, steel ball 6, and brake disc 9 into a whole, and the steel ball 6 is placed in the arc pit 9a of the brake disc 9. The circular hole 5b on the hand chain wheel 5 plays the role of maintaining the running trajectory of the steel ball 6; the pressure plate 4, steel ball 6 and brake disc 9 form a friction pair. The tightening force of the pressure-adjusting nut 2 will cause the pressure fed back to the friction pair by the butterfly spring 3 to change, and the size of the load limiting torque is controlled by adjusting the pressure-adjusting nut 2; after adjusting to the required load limit value, fix the pressure-adjusting nut 2 with the set screw 1 to fix the load limit value.

[0026] The working principle of the non-return pawl 7 is explained: when the manual hoist lifts a load, the hand chain wheel 5 rotates, and the non-return pawl 7 rotates to the arc waist groove 5a. At this time, the non-return pawl 7 pops out due to the action of the head spring. The arc waist groove 5a is designed with an inclined surface, so the non-return pawl 7 is pressed back into the groove of the brake disc 9. When the manual hoist begins to descend, the hand chain wheel 5 rotates in the opposite direction to when it was lifting. The non-return pawl 7 rotates to the arc waist groove 5a. The non-return pawl 7 pops out due to the action of the head spring and enters the arc waist groove 5a and presses against the hand chain wheel 5. At this time, the rotation of the hand chain wheel 5 is no longer restricted by the load limit value of the load limiter, allowing the load to be lowered smoothly.

[0027] The above components are all universal standard parts or components known to those skilled in the art, and their structures and principles can be known to those skilled in the art through technical manuals or conventional experimental methods.

[0028] The specific embodiments described herein are merely illustrative of the spirit of the present invention. Persons skilled in the art may make various modifications, additions, or substitutions to the described specific embodiments without departing from the spirit of the present invention or exceeding the scope defined by the appended claims.

Claims

1. The load limiting device of the hand chain hoist is characterized by: The invention comprises a pressure regulating nut (2), a butterfly spring (3), a pressure plate (4) and a brake disc (9), wherein the brake disc (9) is connected to the hand chain wheel (5) via the pressure regulating nut (2), the butterfly spring (3) and the pressure plate (4) are sleeved on the brake disc (9), and the pressure regulating nut (2), the butterfly spring (3), the pressure plate (4) and the hand chain wheel (5) are arranged in sequence, and a plurality of steel balls (6) are installed on the hand chain wheel (5), and the steel balls (6) are evenly distributed. 9) is provided with a plurality of circular arc pits (9a) that cooperate with the steel ball (6), and a plurality of non-return pawls (7) are rotatably mounted on the brake disc (9), and a cylindrical spring (8) is provided between the non-return pawl (7) and the brake disc (9), and the non-return pawl (7) is arranged obliquely under the elastic force of the cylindrical spring (8), and the hand chain wheel (5) is provided with an arc waist groove (5a) that cooperates with the non-return pawl (7), and the arc waist groove (5a) is an inclined groove.

2. The hand chain hoist load limiting device according to claim 1, characterized in that: The pressure regulating nut (2) is also threadedly connected with a set screw (1).

3. The load limiting device for a hand chain hoist according to claim 1, characterized in that: Both sides of the non-return pawl (7) are provided with mounting shafts (7a), and one end of the non-return pawl (7) is provided with a placement groove (7b) for placing a columnar spring (8).

4. The load limiting device for a hand chain hoist according to claim 1, characterized in that: The hand chain wheel (5) also has a circular hole (5b) that matches the steel ball (6).

5. The load limiting device for a hand chain hoist according to claim 3, characterized in that: The brake disc (9) also has a mounting groove (9b) for mounting a non-return pawl (7).

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