A telescopic limit device for screw conveyor

Abstract

The invention discloses a telescopic limit device applied to a screw conveyor, comprising a base, a connecting rod, a universal joint, a telescopic rod, a telescopic cylinder, a slider, a magnetic sheet and two Hall-type proximity switches. The base and the telescopic cylinder are respectively fixed on the outer walls of two adjacent cylinders that can be axially displaced. One end of the connecting rod is hinged to the base, and the other end is universally connected to one end of the telescopic rod through a universal joint. The other end of the telescopic rod is rotatably fixed to the slider and built into the telescopic cylinder. An axial sliding groove is provided on the inner wall of the bottom of the telescopic cylinder. The slider only moves axially along the sliding groove. The magnetic sheet is built into the slider. The two Hall-type proximity switches are respectively fixed at the first position and the second position of the telescopic cylinder. The telescopic cylinder is axially displaced under the action of an external force to change the axial displacement of the slider, and then change the axial displacement of the magnetic sheet. When the magnetic sheet is located at the first position and the second position, the corresponding Hall-type proximity switch senses the magnetic sheet and sends a limit signal to the outside.

Description

Technical Field

[0001] The invention relates to a telescopic limiting device applied to a screw conveyor. Background Art

[0002] The shield machine is a comprehensive tunnel excavation equipment with multiple functions. At present, the shield machine has become the preferred equipment for underground transportation engineering and tunnel construction. The shield machine consists of a cutter head, a soil bin, a screw conveyor, a main drive, and a personnel bin. The basic working principle of the shield machine is that the slag cut off by the cutter head enters the soil bin through the opening on the cutter head. The slag is mixed and improved in the soil bin to become a fluidized state, and the screw conveyor extends into the soil bin to discharge the soil. Figure 1 As shown, the screw conveyor includes two adjacent and axially displaceable cylinders 1a, 2a and a spiral conveying blade 4a, the two ends of the oil cylinder 3a and the telescopic limit device are respectively fixed to the outer cylinder walls of the front cylinder 1a and the rear cylinder 2a, the rear cylinder 2a moves axially relative to the front cylinder 1a under the action of the oil cylinder 3a, and the spiral conveying blade 4a is rotatably fixed to the rear cylinder 2a, specifically: the spiral conveying blade 4a is fixed to the power source 5a, the power source 5a is rotatably fixed to the base 6a, and the base 6a is fixed to the rear cylinder 2a, therefore, the spiral conveying blade 4a is rotatably fixed to the rear cylinder 2a under the action of the power source 5a and the rear cylinder 2a generates axial displacement with the front cylinder 1a under the action of the oil cylinder 3a.

[0003] When the soil discharge channel of the spiral conveying blade of the screw conveyor is blocked under special circumstances and needs to be cleared, the oil cylinder 3a is extended, and then the telescopic limit device is extended, and the rear cylinder 2a is displaced axially backward relative to the front cylinder 1a, thereby driving the spiral conveying blade to retract the part that penetrates into the soil bin of the shield machine, thereby clearing the blockage.

[0004] At present, the telescopic limit device of the existing screw conveyor is easily affected by processing errors, assembly errors, vibration of the screw conveyor and actual working conditions, which may cause the telescopic rod to bend (such as Figure 2 As shown in the figure), the axis of the telescopic rod deviates from the axis of the telescopic tube, resulting in serious local wear of the telescopic rod. At the same time, the existing telescopic limit device of the screw conveyor has a metal surface as the sensing surface of the proximity switch. After the telescopic rod is bent, the side of the telescopic rod reaches the sensing distance of the proximity switch, and the sensing surface of the proximity switch changes, which seriously affects the measurement result. In addition, the original device is difficult to debug, and the debugging result is greatly affected by the proficiency of the operator.

[0005] In view of this, the inventor conducted in-depth research on the above-mentioned defects in the prior art, and thus came up with this case. Summary of the invention

[0006] The object of the present invention is to provide a telescopic limit device for a screw conveyor, which effectively reduces the bending and wear of the telescopic rod, has high measurement accuracy, good stability, and is easy to debug.

[0007] To achieve the above-mentioned purpose, the present invention discloses a telescopic limit device for a screw conveyor, the telescopic limit device comprising a base, a telescopic cylinder and a telescopic rod, wherein the base and the telescopic cylinder are respectively fixedly arranged on the outer walls of two cylinders of the screw conveyor which are adjacent and axially displaceable, and the telescopic limit device also comprises a connecting rod, a universal joint, a slider, a magnetic sheet and two Hall type proximity switches, one end of the connecting rod is hinged to the base, and the other end thereof is universally connected to one end of the telescopic rod through a universal joint, the other end of the telescopic rod is rotatably fixed to the slider and built into the telescopic cylinder, and the telescopic rod is axially displaced relative to the telescopic cylinder. The inner wall of the bottom of the telescopic cylinder is provided with an axial slide groove, and the slider moves only on the slide groove; the magnetic sheet is built into the slider, and the two Hall-type proximity switches are respectively fixedly installed at the first position and the second position of the telescopic cylinder, and the slider moves axially between the first position and the second position; the telescopic cylinder generates an axial displacement relative to the telescopic rod under the action of external force to change the axial displacement of the slider, and then change the axial displacement of the magnetic sheet. When the magnetic sheet is located at the first position or the second position, the corresponding Hall-type proximity switch senses the magnetic sheet and sends a limit signal to the outside. When the slider moves to the first position S1, the spiral conveying blade is retracted from the gate of the shield body soil bin, and a Hall-type proximity switch senses the magnetic sheet and sends a signal that the screw conveyor is retracted to the outside; when the slider moves to the second position S2, the spiral conveying blade is inserted into the gate of the shield body soil bin, and another Hall-type proximity switch senses the magnetic sheet and sends a signal that the screw conveyor is extended to the outside.

[0008] By adopting the above design, the present invention produces the following beneficial effects: 1. During the extension and retraction process of the screw conveyor, the direction can be automatically fine-tuned through the universal joint to keep the telescopic rod always extending and retracting along the axial direction of the telescopic cylinder, while avoiding bending and wear of the telescopic rod due to processing errors, assembly errors, vibration of the screw conveyor and actual working conditions when the base is directly connected to the telescopic rod; 2. The sensing surface of the proximity switch is replaced by a magnetic sheet from the original metal surface, avoiding other metal surfaces such as the telescopic rod as the sensing object, making the sensing object more specific and improving the stability and accuracy of the measurement; 3. Since the magnetic sheet is fixed on the slider and separated from the telescopic rod, and the slider only moves on the slide groove, the influence of the circumferential rotation of the telescopic rod on the magnetic sheet is avoided, so that the magnetic sheet is always kept on the sensing surface of the Hall-type proximity switch; 4. The device of the present invention is easy to disassemble and assemble, especially during the debugging process, the debugging result is less affected by the proficiency of the operator.

[0009] Furthermore, the cross-section of the slide groove is U-shaped, the bottom of the slider is embedded in the slide groove and moves axially along the slide groove; the bottom of the slider has a receiving groove, the magnetic sheet is wrapped by a rubber sheet and placed in the receiving groove of the slider; the bottom surface of the magnetic sheet is exposed, and the other surfaces are wrapped by rubber sheets, the bottom surface of the receiving groove has a first hole at a position relative to the bottom surface of the magnetic sheet, and the first position and second position of the telescopic cylinder respectively have second holes for the Hall proximity switch to pass through, and the bottom surface of the magnetic sheet serves as the sensing surface of the Hall proximity switch.

[0010] In this configuration, the magnetic sheet is wrapped by a rubber sheet and then built into the interior of the slider, leaving only the bottom surface exposed to serve as the sensing surface of the Hall proximity switch, and the other surfaces are wrapped by rubber elastic sheets to prevent the magnetic sheet from magnetizing the surrounding metal.

[0011] Furthermore, the distance between the bottom surface of the magnetic sheet and each Hall type proximity switch is maintained between 2 mm and 5 mm. Within this numerical range, the Hall type proximity switch can better sense the magnetic sheet.

[0012] Furthermore, a threaded barrel is provided between the telescopic rod and the slider, the end of the threaded barrel facing the telescopic rod is set as an open end, the inner wall of the threaded barrel is provided with a threaded section screwed to the telescopic rod, the other end of the threaded barrel is set as a closed end, and the threaded barrel is rotatably fixed to the slider.

[0013] With such an arrangement, the telescopic rod can move axially and rotate circumferentially. The telescopic rod is screwed to the threaded barrel, and the threaded barrel is rotatably fixed to the slider, thereby avoiding the influence of the circumferential rotation of the telescopic rod on the slider, ensuring the stability of the axial movement of the slider, and thus keeping the magnetic sheet on the sensing surface of the Hall proximity switch at all times.

[0014] Furthermore, it also includes a pin shaft, a gasket and a cotter pin, the closed end of the threaded barrel is provided with a center hole, the slider is provided with an axial countersunk hole, the free end of the pin shaft is provided with a radial through hole, the free end of the pin shaft passes through the countersunk hole and the center hole in sequence until the brim end of the pin shaft abuts against the step surface of the countersunk hole, the gasket is sleeved on the pin shaft and abuts against the inner end of the open end of the threaded barrel, the straight rod section of the cotter pin is inserted into the radial through hole and abuts against the gasket, so that the threaded barrel can be rotatably fixed to the slider through the pin shaft.

[0015] Furthermore, the universal joint is a spherical joint, which is composed of an integrally arranged straight rod portion and a spherical portion. The outer peripheral portion of the straight rod portion is provided with an external thread that cooperates with the internal thread of the connecting rod, so that the straight rod portion of the universal joint is threadedly connected to the connecting rod.

[0016] Furthermore, a front spherical cavity and a rear spherical cavity are provided in sequence from front to back between the universal joint and the telescopic rod, the front spherical cavity is detachably fixed to the rear spherical cavity, and when the two are fixed to each other, a spherical receiving cavity that matches the spherical part of the universal joint is formed, and the front spherical cavity is provided with a through hole for the straight rod part of the universal joint to pass through at the end facing the universal joint, and the diameter of the through hole is smaller than the diameter of the spherical part of the universal joint; the rear spherical cavity is set as an open end at the end facing the telescopic rod, and its inner wall is provided with an internal thread that matches the external thread of the telescopic rod, so that the rear spherical cavity is screwed to the telescopic rod.

[0017] With the above design, during the extension and retraction process of the screw conveyor, the direction can be automatically fine-tuned through the universal joint, so that the telescopic rod is always extended and retracted along the axial direction of the telescopic tube, and the bending and wear of the telescopic rod due to processing errors, assembly errors, vibration of the screw conveyor and actual working conditions when the base is directly connected to the telescopic rod are avoided. In addition, the front spherical cavity is provided with a through hole at one end facing the universal joint for the straight rod part of the universal joint to pass through, and the diameter of the through hole is smaller than the diameter of the spherical part of the universal joint, so that the universal joint is not easy to detach from the front spherical cavity.

[0018] Furthermore, it also includes a first end cover, which covers the front end of the telescopic tube; the front end of the telescopic tube is internally provided with a rubber elastic sleeve, and the rubber elastic sleeve is clamped on the telescopic rod and axially fixed by the first end cover.

[0019] Furthermore, the rear end of the telescopic cylinder is detachably connected to a second end cap. The second end cap is provided to prevent external impurities and foreign bodies from interfering with the normal operation of the slider and to prevent the slider from accidentally falling off when not assembled.

[0020] Furthermore, a plurality of elastic shock-absorbing pads are respectively provided on the top of the base and the telescopic cylinder to reduce the influence of the vibration of the screw conveyor on the telescopic rod.

[0021] Furthermore, a protective cover is provided on the periphery of each Hall type proximity switch to prevent the Hall type proximity switch from being worn. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The detailed description given as non-limiting examples better explains what the invention consists of and how it can be implemented, and furthermore, refers to the accompanying drawings, in which:

[0023] Figure 1 This is a schematic diagram of the local structure of the shield machine;

[0024] Figure 2 It is a schematic diagram of the structure of the telescopic rod bending;

[0025] Figure 3 An exploded view of the present invention;

[0026] Figure 4 It is a combination diagram of the present invention;

[0027] Figure 5 for Figure 4 Cross-sectional view along its AA direction;

[0028] Figure 6 A top view of the telescopic cylinder of the present invention;

[0029] Figure 7 for Figure 6 Cross-sectional view along its BB direction;

[0030] Figure 8 It is a front view of the telescopic cylinder of the present invention;

[0031] Fig. 9 for Figure 8 Cross-sectional view along its CC direction;

[0032] Fig.10 It is a schematic diagram of the extension limit of the screw conveyor of the present invention;

[0033] Fig.11 It is a schematic diagram of the retraction limit of the screw conveyor of the present invention;

[0034] Fig.12 for Figure 3 Enlarged view of point D in the middle.

[0035] Description of the figure number:

[0036] Base 1, connecting rod 2, universal joint 3, straight rod portion 31, spherical portion 32, telescopic rod 4, telescopic cylinder 5, slide groove 51, second hole 52, slider 6, accommodating groove 61, first hole 62, countersunk hole 63, step surface 631, magnetic sheet 7, Hall type proximity switch 8, rubber sheet 9, threaded cylinder 10, open end 101, closed end 102, center hole 1021, front spherical cavity 20, through hole 201, rear spherical cavity 30, spherical receiving cavity 40, first end cover 50, second end cover 60, rubber elastic sleeve 70, elastic shock absorbing pad 80, protective cover 90;

[0037] Screw conveyor 1000 , first position S1 , second position S2 , cylinder 100 a , 100 b , pin 200 , radial through hole 2001 , gasket 300 , cotter pin 400 , oil cylinder 500 . DETAILED DESCRIPTION

[0038] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0039] In the description of the present invention, it is necessary to understand that the terms "center", "front", "rear", "axial", "top", "bottom", "inside", "outside", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0040] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features.

[0041] In the present invention, unless otherwise clearly specified and limited, terms such as "installation", "connection", "fixing" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral one. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0042] The invention discloses a telescopic limit device applied to a screw conveyor. The device is made of conventional materials such as 45 steel, rubber and aluminum alloy, has low cost, simple structure, easy processing and convenient assembly and disassembly.

[0043] like Figures 3 to 5 As shown, the telescopic limit device includes a base 1, a connecting rod 2, a universal joint 3, a telescopic rod 4, a telescopic cylinder 5, a slider 6, a magnetic sheet 7 and two Hall type proximity switches 8.

[0044] like Figure 10-11 As shown, the base 1 and the telescopic cylinder 5 are respectively fixed on the outer walls of two adjacent and axially displaceable cylinders 100a and 100b. The cylinder referred to in the present invention is the cylinder of the screw conveyor 1000. The spiral conveying blades are arranged in the cylinder, and at least one of the cylinders can drive the spiral conveying blades to axially displace relative to the other cylinders. According to the drawings of this specification, the rear cylinder 100b can be axially displaced along the front cylinder 100a under the action of the cylinder 500, and the rear cylinder 100b can drive the spiral conveying blades to axially displace (not shown in the figure).

[0045] like Figure 5 As shown, one end of the connecting rod 2 is hinged to the base 1, and the other end thereof is universally connected to one end of the telescopic rod 4 through a universal joint 3. Specifically, the universal joint 3 is a spherical joint, which is composed of an integrally arranged straight rod portion 31 and a spherical portion 32. The outer peripheral portion of the straight rod portion 31 is provided with an external thread that cooperates with the internal thread of the connecting rod 2, so that the straight rod portion 31 of the universal joint 3 is screwed to the connecting rod 2.

[0046] like Figure 5 As shown, a front spherical cavity 20 and a rear spherical cavity 30 are sequentially provided between the universal joint 3 and the telescopic rod 4 from front to back, the front spherical cavity 20 is screwed to the rear spherical cavity 30, a first hemispherical receiving cavity is provided on the front spherical cavity 20, and a second hemispherical receiving cavity is provided on the rear spherical cavity 30. When the two are fixedly connected to each other, the first hemispherical receiving cavity and the second hemispherical receiving cavity constitute a spherical receiving cavity 40 that matches the spherical portion 32 of the universal joint 3. A through hole 201 is provided at one end of the front spherical cavity 20 facing the universal joint 3 for the straight rod portion 31 of the universal joint 3 to pass through, and the diameter of the through hole 201 is smaller than the diameter of the spherical portion 32 of the universal joint, so that the universal joint 3 is not easy to detach from the front spherical cavity 20. The rear spherical cavity 30 is set as an open end at one end facing the telescopic rod 4, and its inner wall is provided with an internal thread that matches the external thread of the telescopic rod 4, so that the rear spherical cavity 30 is screwed to the telescopic rod 4.

[0047] like Figure 5 As shown, the other end of the telescopic rod 4 is rotatably fixed to the slider 6 and built into the telescopic cylinder 5, and the telescopic rod 4 can move axially and / or rotate circumferentially along the telescopic cylinder 5. Figure 7 and Fig. 9 As shown, the inner wall of the bottom of the telescopic cylinder 5 is provided with an axial U-shaped slot 51, and the bottom of the slider 6 is embedded in the U-shaped slot 51 and only moves axially along the slot 51 to avoid the influence of the circumferential rotation of the telescopic rod 4 on the slider 6.

[0048] Among them, Figure 5 As shown, a threaded barrel 10 is provided between the telescopic rod 4 and the slider 6, one end of the threaded barrel 10 is screwed to the telescopic rod 4, and the other end thereof is rotatably fixed to the slider 6. In this embodiment, the threaded barrel 10 is rotatably fixed to the slider 6 through a pin 200. Specifically, one end of the threaded barrel 10 extending toward the telescopic rod 4 is provided as an open end 101, and a threaded section 1011 screwed to the telescopic rod 4 is provided on its inner wall, and the other end of the threaded barrel 10 is provided as a closed end 102, and the closed end 102 is provided with a center hole 1021. The slider 6 is provided with an axial countersunk hole 63, and the pin 200 is self- A radial through hole 2001 is provided at the end; the free end of the pin shaft 200 passes through the counterbore 63 and the center hole 1021 in sequence until the brim end of the pin shaft 200 abuts against the step surface 631 of the counterbore 63, and a gasket 300 is sleeved on the pin shaft 200 and abuts against the inner end of the open end 101 of the threaded tube 10, and the straight rod section of the cotter pin 400 is passed through the radial through hole 2001 and abuts against the gasket 300, so that the telescopic rod 4 can be rotatably fixed to the slider 6, thereby avoiding the influence of the circumferential rotation of the telescopic rod 4 on the slider 6, ensuring that the slider 6 can only move axially on the slide groove 51.

[0049] like Figure 5 He Ru Fig.12As shown, the bottom of the slider 6 has a receiving groove 61, the magnetic sheet 7 is wrapped by the rubber sheet 9 and built into the receiving groove 61, the bottom surface of the magnetic sheet 7 is exposed, and the other surfaces are wrapped by the rubber sheet 9, and the bottom surface of the receiving groove 61 has a first hole 62 at a position relative to the bottom surface of the magnetic sheet 7, so that the bottom surface of the magnetic sheet 7 serves as the sensing surface of the Hall proximity switch 8 described later.

[0050] like Figure 4 and Figure 5 As shown, the front and rear ends of the telescopic cylinder 5 are respectively provided with a first position S1 and a second position S2, and the first position S1 and the second position S2 of the telescopic cylinder 5 are respectively provided with a second hole 52 for the Hall type proximity switch 8 to pass through. A protective cover 90 is provided on the periphery of each Hall type proximity switch 8, and the two protective covers 90 are respectively locked at the first position S1 and the second position S2 of the telescopic cylinder 5 to prevent the Hall type proximity switch 8 from being worn.

[0051] The working principle of the present invention is as follows: the adjacent front cylinder 100a and rear cylinder 100b move axially under the action of the oil cylinder 500, that is, the fixed end 501 of the oil cylinder 500 is set on the front cylinder 100a, and the telescopic end of the oil cylinder 500 is set on the rear cylinder 500b, driving the rear cylinder 100b to move axially relative to the front cylinder 100a, and then driving the telescopic cylinder 5 fixedly connected to the rear cylinder 100b to move axially, so as to change the axial displacement of the slider 6, and then change the axial displacement of the magnetic sheet 7 fixed on the slider 6. Fig.11 When the slider 6 moves toward the first position S1, that is, the rear cylinder 100b moves away from the front cylinder 100a, the screw conveying blade is retracted from the gate of the shield soil bin, and the Hall proximity switch 8 senses the magnetic sheet 7 and sends a signal that the screw conveyor is retracted to the outside, so that the telescopic rod of the oil cylinder 500 stops extending outward; Fig.10 When the slider 6 moves toward the second position S2, that is, the rear cylinder 100b is axially displaced toward the front cylinder 100a, when the slider 6 moves to the second position S2, the spiral conveying blade is inserted into the gate of the shield soil bin, and another Hall type proximity switch 8 senses the magnetic sheet 7 and sends a signal that the screw conveyor is in place, so that the telescopic rod of the oil cylinder 500 stops retracting inward.

[0052] Preferably, the distance between the bottom surface of the magnetic sheet 7 and each Hall type proximity switch 8 is maintained between 2 mm and 5 mm. Within this numerical range, the Hall type proximity switch 8 can better sense the magnetic sheet 7 .

[0053] like Figure 4 As shown, a plurality of elastic shock-absorbing pads 80 are respectively provided on the top of the base 1 and the telescopic cylinder 5 to reduce the influence of the vibration of the screw conveyor 1000 on the telescopic limit device.

[0054] like Figure 5 As shown, it also includes a rubber elastic sleeve 70, a first end cover 50 and a second end cover 60. The rubber elastic sleeve 70 is built into the front end of the telescopic cylinder 5 and clamped on the telescopic rod 4. The setting of the rubber elastic sleeve 70 can ensure the stability of the axial extension of the telescopic rod 4 and reduce the impact of the vibration of the screw conveyor 1000 on the telescopic limit device. The first end cover 50 covers the front end of the telescopic cylinder 5 to achieve axial fixation of the rubber elastic sleeve 70. The second end cover 60 and the second rear end cover 60 are set to prevent external impurities and foreign objects from interfering with the normal operation of the slider, play a protective role, and prevent the slider from accidentally falling off when not assembled.

[0055] The key points of the present invention are: 1. In the process of the rear cylinder 100 extending and retracting relative to the front cylinder 100, the direction can be automatically fine-tuned through the universal joint 3 to keep the telescopic rod 4 always extending and retracting along the axial direction of the telescopic cylinder 5, while avoiding bending and wear of the telescopic rod 4 due to processing errors, assembly errors, vibration of the screw conveyor 1000 and actual working conditions when the base 1 is directly connected to the telescopic rod 4; 2. The sensing surface of the proximity switch is replaced by the magnetic sheet 7 from the original metal surface, avoiding other metal surfaces such as the telescopic rod 4 as sensing objects, making the sensing object more specific, and improving the stability and accuracy of the measurement; 3. Since the magnetic sheet 7 is fixed on the slider 6 and separated from the telescopic rod 4, and the slider 6 only moves on the slide groove 51, the influence of the circumferential rotation of the telescopic rod 4 on the magnetic sheet 7 is avoided, so that the magnetic sheet 7 always remains on the sensing surface of the Hall-type proximity switch 8.

[0056] Optimally, when assembling the telescopic limit device, an anaerobic adhesive is applied to the threaded surface for anti-loosening and tightening to prevent the thread from loosening under abnormal working conditions and thus affecting the measurement accuracy.

[0057] The above embodiments and illustrations do not limit the product form and style of the present invention. Any appropriate changes and modifications made by ordinary technicians in the relevant technical field should be deemed to be within the patent scope of the present invention.

Claims

1. A telescopic limit device for a screw conveyor, the telescopic limit device comprising a base (1), a telescopic cylinder (5) and a telescopic rod (4), wherein the base (1) and the telescopic cylinder (5) are respectively fixedly mounted on the outer walls of two cylinders (100a, 100b) of a screw conveyor (1000) that are adjacent and axially displaceable, and characterized in that: It also includes a connecting rod (2), a universal joint (3), a slider (6), a magnetic sheet (7), and two Hall-type proximity switches (8). One end of the connecting rod (2) is hinged to the base (1), and the other end is universally connected to one end of a telescopic rod (4) through a universal joint (3). The other end of the telescopic rod (4) is rotatably fixed to the slider (6) and built into the telescopic cylinder (5). The telescopic rod (4) is axially displaced relative to the telescopic cylinder (5). An axial sliding groove (51) is provided on the inner wall of the bottom of the telescopic cylinder (5). The slider (6) moves only on the sliding groove (51). The magnetic sheet (7) is built into the slider. The block (6) comprises two Hall type proximity switches (8) which are respectively fixedly mounted at a first position (S1) and a second position (S2) of the telescopic cylinder (5); the slider (6) is axially displaced between the first position (S1) and the second position (S2); the telescopic cylinder (5) generates an axial displacement relative to the telescopic rod (4) under the action of an external force, so as to change the axial displacement of the slider (6), and then change the axial displacement of the magnetic sheet (7); when the magnetic sheet (7) is located at the first position (S1) or the second position (S2), the corresponding Hall type proximity switch (8) senses the magnetic sheet (7) and sends a limit signal to the outside; The cross section of the slide groove (51) is U-shaped, the bottom of the slider (6) is embedded in the slide groove (51) and moves axially along the slide groove (51); the bottom of the slider (6) has a receiving groove (61), the magnetic sheet (7) is wrapped by a rubber sheet (9) and placed in the receiving groove (61) of the slider (6); the bottom surface of the magnetic sheet (7) is exposed, and the other surfaces are wrapped by the rubber sheet (9); the bottom surface of the receiving groove (61) has a first hole (62) at a position relative to the bottom surface of the magnetic sheet (7); the telescopic cylinder (5) has a second hole (52) for the Hall type proximity switch (8) to pass through at the first position (S1) and the second position (S2), respectively, and the bottom surface of the magnetic sheet (7) serves as the sensing surface of the Hall type proximity switch (5); A threaded barrel (10) is provided between the telescopic rod (4) and the slider (6); one end of the threaded barrel (10) facing the telescopic rod (4) is provided as an open end (101); an inner wall of the threaded barrel (10) is provided with a threaded section threadedly connected to the telescopic rod (4); the other end of the threaded barrel (10) is provided as a closed end (102); and the threaded barrel (10) is rotatably fixed to the slider (6); It also includes a pin shaft (200), a gasket (300) and a split pin (400); the closed end (102) of the threaded barrel (10) is provided with a center hole (1021); the slider (6) is provided with an axial countersunk hole (63); the free end of the pin shaft (200) is provided with a radial through hole (2001); the free end of the pin shaft (200) passes through the countersunk hole (63) and the center hole (1021) in sequence until the brim end of the pin shaft (200) abuts against the step surface (631) of the countersunk hole (63); the gasket (300) is sleeved on the pin shaft (200) and abuts against the inner end of the open end (101) of the threaded barrel (10); the straight rod section of the split pin (400) is inserted into the radial through hole (2001) and abuts against the gasket (300), so that the threaded barrel (10) is rotatably fixed to the slider (6) through the pin shaft (200).

2. A telescopic limiter device for a screw conveyor as claimed in claim 1, characterized in that: The universal joint (3) is a spherical joint, and is composed of a straight rod portion (31) and a spherical portion (32) which are integrally arranged. The outer peripheral portion of the straight rod portion (31) is provided with an external thread which cooperates with the internal thread of the connecting rod (2), so that the straight rod portion (31) of the universal joint (3) is threadedly connected to the connecting rod (2).

3. A telescopic limit device for a screw conveyor as claimed in claim 2, characterized in that: A front spherical cavity (20) and a rear spherical cavity (30) are provided in sequence from front to back between the universal joint (3) and the telescopic rod (4); the front spherical cavity (20) is detachably fixed to the rear spherical cavity (30); when the two are fixed to each other, a spherical receiving cavity (40) is formed that matches the spherical portion (32) of the universal joint (3); the front spherical cavity (20) is provided with a through hole (201) at one end facing the universal joint (3) for the straight rod portion (31) of the universal joint (3) to pass through, and the diameter of the through hole (201) is smaller than the diameter of the spherical portion (32) of the universal joint; the rear spherical cavity (30) is provided with an open end at one end facing the telescopic rod (4), and an inner wall thereof is provided with an internal thread that matches the external thread of the telescopic rod (4), so that the rear spherical cavity (30) is screwed to the telescopic rod (4).

4. The telescopic limiting device for a screw conveyor according to claim 1, characterized in that: It also comprises a first end cover (50) which covers the front end of the telescopic cylinder (5); a rubber elastic sleeve (70) is built into the front end of the telescopic cylinder (5); the rubber elastic sleeve (70) is clamped on the telescopic rod (4) and axially fixed by the first end cover (50).

5. The telescopic limiting device for a screw conveyor according to claim 1, characterized in that: The rear end of the telescopic cylinder (5) is detachably connected to a second end cover (60).

6. A telescopic limit device for a screw conveyor according to any one of claims 1 to 5, characterized in that: A plurality of elastic shock-absorbing pads (80) are respectively provided on the top of the base (1) and the telescopic cylinder (5) to reduce the impact of the screw conveyor (1000) vibrating on the telescopic rod (4).

7. The telescopic limit device for a screw conveyor according to claim 1, characterized in that: A protective cover (90) is provided on the periphery of each Hall-type proximity switch (8).

Images