Lockable lanyard switch

Abstract

This utility model relates to a lockable pull cord switch, which includes a housing (1), a drive shaft (2), a drive arm (3), a torsion spring (4), a sensing block (5), a magnetic sensing head (6), and a reset lever (7). The drive shaft (2) is rotatably mounted on the housing (1), the drive arm (3) is mounted on the end of the drive shaft (2), the sensing block (5) is mounted on the drive shaft (2), the magnetic sensing head (6) is mounted inside the housing (1), the torsion spring (4) is fitted on the drive shaft (2), and the reset lever (7) is slidably mounted on the housing (1). One end of the reset lever (7) is engaged with a transmission frame (51), and the other end extends outside the housing (1). A compression spring (71) is fitted on the reset lever (7). A lock frame (11) is provided outside the housing (1) at the position where it engages with the reset lever (7), and a lock hole (12) is provided on the lock frame (11). After it is activated, it can be manually locked to prevent the switch from being manually or accidentally reset, which is beneficial to protecting the safety of on-site maintenance personnel and equipment.

Description

Technical Field

[0001] This utility model relates to electrical switches, specifically to a lockable pull cord switch. Background Technology

[0002] Pull-cord switches are commonly used safety protection devices on belt conveyors, elevators, and other conveying equipment. They are installed on the frames on both sides of the equipment. In the event of an emergency, pulling the wire rope at any point along the conveyor line causes the drive arm of the pull-cord switch to rotate. This rotation, via the transmission shaft, displaces the sensing block, activating the magnetic sensor head and cutting off the control circuit of the conveyor, thus stopping the equipment and preventing the accident from escalating. Pull-cord switches are a type of contactless limit switch, characterized by easy installation, reliable switching, stable performance, long service life, strong anti-interference capabilities, and ideal application results. Pull-cord switches have two reset methods: automatic reset and manual reset. During equipment shutdown and maintenance, the manually reset pull-cord switch must always be in the open state. An accidental reset could cause the equipment to start unexpectedly, leading to unnecessary trouble and danger for maintenance personnel and the equipment itself. Summary of the Invention

[0003] The purpose of this invention is to provide a lockable pull rope switch that can be manually locked after being triggered to prevent accidental reset from causing the equipment to start, thus protecting the safety of on-site maintenance personnel and equipment.

[0004] The technical solution of this utility model is as follows: It includes a housing, a drive shaft, a drive arm, a torsion spring, a sensing block, a magnetic sensing head, and a reset lever. One end of the drive shaft extends outside the housing and is rotatably mounted on the housing. The drive arm is mounted on the end of the drive shaft located outside the housing. The sensing block is located inside the housing and is mounted on the drive shaft via a transmission frame. The magnetic sensing head is mounted inside the housing in cooperation with the sensing block. The torsion spring is located inside the housing and is fitted onto the drive shaft. One end of the torsion spring cooperates with the transmission frame, and the other end cooperates with the housing. The reset lever is slidably mounted on the housing along the radial direction of the drive shaft. One end of the reset lever extends inside the housing and cooperates with the transmission frame, and the other end extends outside the housing. A compression spring is fitted on the reset lever. The end of the compression spring facing inside the housing cooperates with the reset lever, and the end facing outside the housing cooperates with the housing. A locking frame is provided at the position outside the housing where the reset lever cooperates. The locking frame has a locking hole that blocks the reset lever after a locking rod is inserted, preventing the reset lever from releasing the drive arm.

[0005] The technical advantages of this invention are: it can be manually locked after activation to prevent accidental or unintended reset, thus protecting the safety of on-site maintenance personnel and equipment. It is easy to operate, highly sensitive, and has strong anti-interference capabilities, making it safer and more reliable. Its simple and robust structure facilitates installation, use, and maintenance, and its longer service life makes it more suitable for widespread application. Attached Figure Description

[0006] Figure 1 This is a perspective view of an embodiment of the present utility model; Figure 2 This is an exploded perspective view of an embodiment of the present utility model. Detailed Implementation

[0007] like Figure 1 , Figure 2 As shown, it includes a housing 1, a drive shaft 2, a drive arm 3, a torsion spring 4, a sensing block 5, a magnetic sensing head 6, and a reset lever 7. One end of the drive shaft 2 extends outside the housing 1 and is rotatably mounted on the housing 1. The drive arm 3 is mounted on the end of the drive shaft 2 located outside the housing 1. The sensing block 5 is located inside the housing 1 and is mounted on the drive shaft 2 via a drive frame 51. The magnetic sensing head 6 is mounted inside the housing 1 in conjunction with the sensing block 5. The torsion spring 4 is located inside the housing 1 and is fitted onto the drive shaft 2. One end of the torsion spring 4 is engaged with the drive frame 51, and the other end is engaged with the housing 1. The reset lever 7 is slidably mounted on the housing 1 along the radial direction of the drive shaft 2. One end of the reset lever 7 extends into the housing 1 and cooperates with the drive frame 51, while the other end extends out of the housing 1. A compression spring 71 is fitted on the reset lever 7. The end of the compression spring 71 facing into the housing 1 cooperates with the reset lever 7, and the end facing out of the housing 1 cooperates with the housing 1. A locking frame 11 is provided at the position outside the housing 1 where it cooperates with the reset lever 7. The locking frame 11 is provided with a locking hole 12 that blocks the reset lever 7 after the locking rod is inserted, so that the reset lever 7 cannot release the drive arm 3.

[0008] The housing 1 is composed of a large half-shell 13 and a small half-shell 14 that are interlocked as a whole. The large half-shell 13 and the small half-shell 14 are respectively provided with connecting flanges 15 at their respective joint positions. The connecting flange 15 of the large half-shell 13 is provided with several threaded holes 16, and the connecting flange 15 of the small half-shell 14 is provided with several screw holes 17 corresponding to the threaded holes 16. The small half-shell 14 is connected to the large half-shell 13 by several screws 0 that pass through the screw holes 17 and connect to the threaded holes 16. The outer side wall of the large half-shell 13 is provided with a mounting base 18, and the mounting base 18 is provided with two mounting holes 19.

[0009] A sealing groove is provided circumferentially on the annular mating surface where the small half-shell 14 and the large half-shell 13 interlock, and a sealing ring 00 is provided in the sealing groove to seal with the large half-shell 13.

[0010] The drive shaft 2 extends out of the housing 1 with a D-shaped cross-section and a threaded end. The drive arm 3 has a D-shaped hole 31 in the middle that mates with the drive shaft 2. The drive arm 3 is fitted onto the drive shaft 2 through the D-shaped hole 31 and fixedly mounted on the drive shaft 2 by a nut 10. A flat washer 20 and a spring washer 30, both fitted onto the drive shaft 2, are provided between the drive arm 3 and the nut 10. The nut 10 is a round-headed nut.

[0011] The drive arm 3 is a long plate-shaped body with both ends bent laterally in the same direction 32. The two laterally bent parts 32 of the drive arm 3 are respectively provided with wire rope connection holes 33, and D-shaped holes 31 are provided in the middle of the drive arm 3.

[0012] The outer end face of the housing 1 corresponding to the drive arm 3 is provided with left and right limiting blocks 34 that cooperate with the drive arm 3.

[0013] The housing 1 is equipped with two magnetic sensing heads 6 located on different sides of the sensing block 5. The housing 1 is also equipped with a wiring block 8. The lead wires of the two magnetic sensing heads 6 are connected to the wiring block 8 respectively. The side wall of the housing 1 is equipped with a lead wire seat 40. The lead wire seat 40 is equipped with an external lead wire 50, one end of which is connected to the two magnetic sensing heads 6 through the wiring block 8 respectively, and the other end extends through the lead wire seat 40 to the outside of the housing 1.

[0014] The reset lever 7 is slidably engaged with the lever seat 72, which is threadedly mounted on the housing 1. The end of the compression spring 71 facing inward toward the housing 1 engages with the reset lever 7, and the end facing outward toward the housing 1 engages with the lever seat 72.

[0015] The reset lever 7 is provided with a reset lever 73 located outside the housing 1. One end of the reset lever 73 is hinged to the end of the reset lever 7 located outside the housing 1. The end face of the reset lever 73 hinged to the reset lever 7 is the plane that mates with the housing 1 when the reset lever 73 is upright. One side of the reset lever 73 adjacent to this plane is the plane that mates with the housing 1 when the reset lever 73 is tilted down, perpendicular to the end plane of the reset lever 7. The corner of the reset lever 73 between the two planes is a rounded corner that slides into contact with the housing 1. The distance between the end plane of the reset lever 73 and the hinge axis is less than the distance between the side plane and the hinge axis. When the reset lever 73 is upright, the reset lever 7 is released. When tilted down, the reset lever 7 is pulled outward, releasing the transmission frame 51, the transmission shaft 2, and the drive arm 3.

[0016] The lock frame 11 is a rod-shaped body with a U-shaped cross-section. The lock frame 11 extends along the axial direction of the reset pull rod 7, and one end is fixedly connected to the housing 1 (pull rod seat). The reset lever 73 stands upright in the U-shaped groove of the lock frame 11. Several lock holes 12 are arranged along the axial direction of the reset pull rod 7 on the side walls of the lock frame 11 on both sides of the U-shaped groove. The reset lever 73 is provided with a notch 74 at the position that cooperates with each lock hole 12 on the lock frame 11 to avoid the lock rod passing through the lock hole 12. The side of the reset lever 73 is provided with a limiting protrusion 75 at one end that is laterally connected to the reset lever 73. The lock frame 11 is provided with a limiting hole 76 at the position that cooperates with the limiting protrusion 75. When the locking rod is inserted into the locking hole 12 on the locking frame 11, the locking rod jams the reset lever 73, preventing the reset lever 73 from being turned down. The limiting hole 76 jams the limiting protrusion 75, preventing the reset pull rod 7 from being pulled out. This prevents the reset pull rod 7 from retracting and releasing the transmission frame 51, transmission shaft 2 and drive arm 3, thus playing a safety role in preventing the pull rope switch from resetting.

[0017] Operating principle: When this device is in use, the end of the drive arm 3 is connected to the equipment frame via a steel wire rope.

[0018] In the event of an emergency with the conveyor equipment, pulling the wire rope at any point along the line will cause the drive arm 3 of the pull rope switch to rotate. The drive arm 3 then drives the transmission shaft 2 to rotate against the torque of the torsion spring 4. The transmission frame 51, mounted on the transmission shaft 2, pushes against the end of the reset lever 7 against the pressure of the compression spring 71. When the transmission frame 51 rotates past the end of the reset lever 7 and no longer pushes against it, the reset lever 7 rebounds under the action of the compression spring 71. When the wire rope is released, the drive arm 3 rebounds under the action of the torsion spring 4, and the transmission frame 51 is locked by the end of the reset lever 7. As the drive arm 3 rotates due to the wire rope, the sensing block 5 on the transmission frame 51, via the magnetic sensor head 6, activates the magnetic sensor head 6, cutting off the control circuit of the conveyor device and stopping the conveyor equipment to prevent the accident from escalating.

[0019] After the accident is resolved, when the pull rope switch needs to be reset, the end of the reset lever 73 away from the reset pull rod 7 is flipped down so that the reset lever 73 is perpendicular to the reset pull rod 7. During the process of the reset lever 73 being flipped down, it will overcome the elastic force of the compression spring 71 and pull the reset pull rod 7 outward. The end of the reset pull rod 7 retracts towards the inside of the housing 1, releasing the transmission frame 51. The transmission shaft 2 and the drive arm 3 drive the sensing block 5 to rebound under the action of the torsion spring 4, so that the pull rope switch is reset.

[0020] When handling accidents on site, in order to prevent the pull rope switch from being accidentally reset, several locks can be added to the lock frame 11. Each lock rod passes through the lock hole 12 on the lock frame 11 and locks the reset lever 73, so that the reset lever 73 cannot be turned down. In addition, the limit hole 76 locks the limit protrusion 75, so that the reset pull rod 7 will not retract and release the transmission frame 51, transmission shaft 2 and drive arm 3, thereby playing a safety role in preventing the pull rope switch from being reset.

Claims

1. A lockable pull cord switch, comprising a housing (1), a drive shaft (2), a drive arm (3), a torsion spring (4), a sensing block (5), a magnetic sensing head (6), and a reset lever (7). One end of the drive shaft (2) extends outside the housing (1) and is rotatably mounted on the housing (1). The drive arm (3) is mounted on the end of the drive shaft (2) located outside the housing (1). The sensing block (5) is located inside the housing (1) and mounted on the drive shaft (2) via a transmission frame (51). The magnetic sensing head (6) is fitted with the sensing block (5) and mounted inside the housing (1). The torsion spring (4) is located inside the housing (1). The inner sleeve is mounted on the drive shaft (2). One end of the torsion spring (4) is engaged with the drive frame (51), and the other end is engaged with the housing (1). The reset lever (7) is slidably mounted on the housing (1) along the radial direction of the drive shaft (2). One end of the reset lever (7) extends into the housing (1) and engages with the drive frame (51), while the other end extends out of the housing (1). A compression spring (71) is mounted on the reset lever (7). The end of the compression spring (71) facing inward toward the housing (1) engages with the reset lever (7), and the end facing outward toward the housing (1) engages with the housing (1). The feature is that: A locking frame (11) is provided on the outside of the housing (1) at the position that cooperates with the reset lever (7). The locking frame (11) has a locking hole (12) that blocks the reset lever (7) after the locking rod is inserted, so that the reset lever (7) cannot release the drive arm (3).

2. The lockable pull cord switch as described in claim 1, characterized in that... The housing (1) is composed of a large half-shell (13) and a small half-shell (14) that are interlocked as a whole. The large half-shell (13) and the small half-shell (14) are respectively provided with connecting flanges (15) at the joint positions. The connecting flange (15) of the large half-shell (13) is provided with several threaded holes (16). The connecting flange (15) of the small half-shell (14) is provided with several screw holes (17) corresponding to the threaded holes (16). The small half-shell (14) is connected to the large half-shell (13) by several screws (0) that pass through the screw holes (17) and connect to the threaded holes (16). The side wall of the large half-shell (13) is provided with a mounting seat (18). The mounting seat (18) is provided with two mounting holes (19).

3. The lockable pull cord switch as described in claim 2, characterized in that... The annular mating surface of the small half shell (14) and the large half shell (13) is provided with a sealing ring groove in the circumferential direction, and a sealing ring (00) is provided in the sealing ring groove to seal with the large half shell (13).

4. The lockable pull cord switch as described in claim 1, characterized in that... The drive shaft (2) extends to the outside of the housing (1) with a D-shaped cross section and a threaded end. The drive arm (3) has a D-shaped hole (31) in the middle that matches the drive shaft (2). The drive arm (3) is fitted onto the drive shaft (2) through the D-shaped hole (31) and fixedly installed on the drive shaft (2) by a nut (10).

5. The lockable pull cord switch as described in claim 1, characterized in that... The drive arm (3) is a long sheet-like body with both ends bent laterally in the same direction (32). The two laterally bent (32) of the drive arm (3) are respectively provided with wire rope connection holes (33) and D-shaped holes (31) are provided in the middle of the drive arm (3).

6. The lockable pull cord switch as described in claim 1, characterized in that... The outer end face of the housing (1) corresponding to the drive arm (3) is provided with left and right limiting blocks (34) that cooperate with the drive arm (3).

7. The lockable pull cord switch as described in claim 1, characterized in that... The housing (1) is equipped with two magnetic sensing heads (6) located on different sides of the sensing block (5). The housing (1) is also equipped with a wiring block (8). The lead wires of the two magnetic sensing heads (6) are connected to the wiring block (8) respectively. The housing (1) is equipped with a lead wire seat (40) on its side wall. The lead wire seat (40) is equipped with an external lead wire (50) with one end connected to the two magnetic sensing heads (6) through the wiring block (8) and the other end extending through the lead wire seat (40) to the outside of the housing (1).

8. The lockable pull cord switch as described in claim 1, characterized in that... The reset lever (7) is slidably engaged with the lever seat (72) which is threadedly mounted on the housing (1). The end of the compression spring (71) facing inside the housing (1) is engaged with the reset lever (7), and the end facing outside the housing (1) is engaged with the lever seat (72).

9. The lockable pull cord switch as described in claim 1, characterized in that... The reset lever (7) is provided with a reset lever (73) located outside the housing (1). One end of the reset lever (73) is hinged to the end of the reset lever (7) located outside the housing (1). The end face of the reset lever (73) hinged to the reset lever (7) is the plane that cooperates with the housing (1) when the reset lever (73) is upright. One side of the reset lever (73) adjacent to this plane is the plane that cooperates with the housing (1) when the reset lever (73) is flipped down, perpendicular to the end plane of the reset lever (7). The corner of the reset lever (73) between the two planes is a rounded corner that slides and contacts the housing (1). The distance between the end plane of the reset lever (73) and the hinge axis is less than the distance between the side plane and the hinge axis.

10. The lockable pull cord switch as described in claim 9, characterized in that... The lock frame (11) is a rod-shaped body with a U-shaped cross section. The lock frame (11) extends along the axial direction of the reset pull rod (7) and is fixedly connected to the housing (1) at one end. The reset lever (73) stands upright in the U-shaped groove of the lock frame (11). Several lock holes (12) are arranged along the axial direction of the reset pull rod (7) on the side walls of the lock frame (11) on both sides of the U-shaped groove. The reset lever (73) is provided with a notch (74) at the position that cooperates with each lock hole (12) on the lock frame (11) to avoid the lock rod passing through the lock hole (12). The side of the reset lever (73) is provided with a limiting protrusion (75) that is laterally connected to the reset lever (73). The lock frame (11) is provided with a limiting hole (76) at the position that cooperates with the limiting protrusion (75).

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