Mechanical overspeed device with center of gravity offset

Abstract

The application provides a gravity center offset type mechanical overspeed device, which comprises a rotating shaft clamp, a fly pendulum device installed on the rotating shaft clamp, a counterweight, a collision arm connected with the fly pendulum device, and an electric signal device connected with the collision arm; the rotating shaft clamp is used for being installed on one side of a rotating shaft; the fly pendulum device comprises a shell, a rotating pivot arranged in the shell, an eccentric block and a weight; the weight is detachably installed in the eccentric block; the eccentric block can rotate around the rotating pivot; when the rotating shaft reaches an alarm rotating speed, the eccentric block rotates around the rotating pivot, extends out of the shell and is limited by the shell; the part of the eccentric block extending out of the shell touches the collision arm, and triggers the electric signal device to send an electric signal for stopping the rotation of the rotating shaft. The application does not have a spring structure, is not affected by spring stiffness change, is more reliable, has no over-stretching state when the rotating speed exceeds the alarm rotating speed, and does not interfere with other structures.

Description

Technical Field

[0001] This invention relates to a mechanical overspeed device, specifically a center-of-gravity offset mechanical overspeed device. Background Technology

[0002] A mechanical overspeed device is used to stop a rotating shaft when its rotational speed exceeds or equals a warning speed. Existing mechanical overspeed devices mainly consist of a pendulum, a protruding spring mechanism, and a collision arm. The pendulum primarily comprises a housing and a spring housing structure. As the rotational speed increases, the spring tension increases until the shaft reaches the warning speed. At this point, the spring's end collides with the collision arm, triggering an action potential and stopping the shaft's rotation via a signal, thus completing the emergency stop procedure.

[0003] However, current mechanical overspeed devices largely rely on the characteristics of springs: the stiffness of the spring remains constant in its linear portion. But because the rotating shaft maintains high-speed rotation for extended periods, the spring remains under tension for a long time. During prolonged tension, the spring may undergo unexpected plastic deformation, causing its stiffness to deviate from its constant value, disrupting its linearity, and resulting in the spring reaching the required elongation before or after the warning speed. Ultimately, the spring contacts the collision arm at a speed exceeding or preceding the warning speed, causing the mechanical overspeed device to fail to achieve its intended effect. Summary of the Invention

[0004] In view of the above-mentioned shortcomings of the existing technology, the purpose of the present invention is to provide a mechanical overspeed device that does not require a spring, has only two states: overspeed and non-overspeed, and whose center of gravity position can be adjusted to adjust the warning speed.

[0005] A center-of-gravity offset mechanical overspeed device includes a rotating shaft clamp, a pendulum device mounted on the rotating shaft clamp, a counterweight, a collision arm linked to the pendulum device, and an electrical signal device connected to the collision arm. The rotating shaft clamp is used to install on one side of the rotating shaft. The pendulum device includes a housing, a rotating fulcrum located inside the housing, an eccentric block, and a counterweight. The counterweight is detachably installed inside the eccentric block, and the eccentric block can rotate around the rotating fulcrum. When the rotating shaft reaches a warning speed, the eccentric block rotates around the rotating fulcrum and extends out of the housing and is restricted by the housing. The extended part of the eccentric block contacts the collision arm, triggering the electrical signal device to send an electrical signal to stop the rotation of the rotating shaft.

[0006] Furthermore, the rotating shaft clamp is a two-semi-circular structure, which is spliced ​​together and installed on one side of the rotating shaft. The pendulum device and the counterweight are respectively installed at the splicing point.

[0007] Furthermore, the head of the rotating shaft clamp is fixed to the side plate, and the side plate clamps the outer shell and the counterweight respectively.

[0008] Furthermore, the eccentric block is provided with a hollow threaded slot, in which a weight is installed that moves inward by rotation.

[0009] Furthermore, the bottom of the outer casing is provided with a herringbone corner to support the eccentric block.

[0010] Furthermore, the side plate is provided with a herringbone angle to limit the displacement of the eccentric block. There is a gap between the herringbone angle and the eccentric block to ensure that the contact area between the two is small after rotation and to reduce the probability of friction.

[0011] Furthermore, the outer shell and side plate are welded to the connecting block, and the connecting block is connected to the rotating shaft clamp by fasteners.

[0012] Furthermore, the bottom of the housing is provided with a drain port for draining water or oil that has seeped into the machine.

[0013] Furthermore, the eccentric block cannot be magnetically attracted to the materials of the outer shell and side plates.

[0014] Furthermore, the eccentric block, the outer shell, and the side plates are made of brass or stainless steel.

[0015] Compared with ordinary spring-type mechanical speed-over-speed devices, the present invention has the following main advantages:

[0016] 1. Springless structure, not affected by changes in spring stiffness, making it more reliable;

[0017] 2. When the speed exceeds the warning speed, there is no overstretching state and no interference with other structures. Attached Figure Description

[0018] Figure 1 This is a three-dimensional structural diagram of a center-of-gravity offset mechanical overspeed device according to an embodiment of the present invention;

[0019] Figure 2 This is a top view of the rotating shaft in an embodiment of the present invention;

[0020] Figure 3 This is a side sectional view of an embodiment of the present invention;

[0021] Figure 4 This is a top view of an embodiment of the present invention;

[0022] Figure 5 This is a schematic diagram illustrating the connection method between the side plate and the outer shell in an embodiment of the present invention;

[0023] Figure 6 This is a schematic diagram of the base fixing connection method according to an embodiment of the present invention;

[0024] Figure 7This is a schematic diagram of the collision arm according to an embodiment of the present invention;

[0025] Figure 8 This is a schematic diagram illustrating the working principle of an embodiment of the present invention.

[0026] The reference numerals in the figure are described below:

[0027] 1—Eccentric block, 2—Outer shell, 3—Rotation fulcrum, 4—Drain outlet, 5—Side plate, 6—Hollow threaded groove, 7—Side plate herringbone corner, 8—Weight block, 9—Rotating shaft clamp, 10—Counterweight block, 11—Collision arm, 12—Bottom herringbone corner, 13—Connecting block, 14—Locking fastener, 15—Rotating shaft. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] Please see Figure 1-8 This invention discloses a center-of-gravity offset type mechanical overspeed device, which utilizes the offset of the center of gravity of the eccentric block 1 at high speed to collide with a rotating wall to perform the action. The device includes a rotating shaft clamp 9, a pendulum device installed on the rotating shaft clamp 9, a counterweight block 10, a collision arm 11 linked with the pendulum device, and an electrical signal device connected to the collision arm 11.

[0030] The rotating shaft clamp 9 consists of two semi-circular structures. The two semi-circles are joined together and installed on the rotating shaft 15 (e.g., Figure 2 On one side (as shown), the pendulum device and the counterweight 10 are respectively installed at the splicing point. Specifically, the rotating shaft clamp 9 is fixed to the outside of the rotating shaft 15, the head of the rotating shaft clamp 9 is fixed to the side plate 5, the side plate 5 clamps the outer shell 2 and the counterweight 10 respectively, and the eccentric block 1 cannot be magnetically attracted to the materials of the outer shell 2 and the side plate 5.

[0031] like Figure 3As shown, the pendulum device includes a housing 2, a pivot 3 located within the housing 2, an eccentric block 1, and a weight 8. The pivot 3 contacts the housing 2, ensuring that when the rotating shaft 15 reaches the warning speed, the pivot 3, in contact with the housing, hinders the eccentric block 1 from rotating around the support 12. The eccentric block 1 only rotates around the pivot 3, and due to the direction of rotation of the eccentric block, the gravitational arm gradually decreases to establish a positive feedback system, ensuring that the eccentric block 1 does not rebound. During rotation, the eccentric block 1 is restricted by the housing 2 and will not fly out of the housing 2, and will stop rotating after a certain period of rotation due to the influence of the housing 2. Specifically, the side plates 5 are bolted to both sides of the housing 2, and the side plates 5 can restrict the tangential displacement of the eccentric block 1, thereby ensuring that the eccentric block 1 will not fly out of the pendulum device.

[0032] The eccentric block 1 is provided with a hollow threaded slot 6, and a weight 8 that can be rotated and moved inward can be installed in the hollow threaded slot 6. The weight 8 can adjust the center of gravity of the entire eccentric block 1 to adjust the warning speed at which deflection occurs.

[0033] The bottom of the outer shell 2 is provided with a bottom herringbone corner 12 for supporting the eccentric block 1; the side plate 5 is provided with a side plate herringbone corner 7 for limiting the displacement of the eccentric block 1.

[0034] like Figure 3 As shown, when the rotating shaft 15 is not rotating, the eccentric block 1 rests flat on the bottom herringbone corner 12 and is supported by the bottom herringbone corner 12. The rotation fulcrum 3 is in close contact with the outer shell 2. The eccentric block 1 and the two side plates 5 are restricted by the elongated protrusions of the herringbone corners 7 of the side plates (e.g., Figure 3 and Figure 4 As shown in Figure 6, the outer shell 2 and the side plate 5 are welded together on a connecting block 13. The size of the connecting block 13 is determined by the required rotating shaft 15. The connecting block 13 and the rotating shaft clamp 9 are connected by fasteners 14 (e.g., studs and nuts). After both sides are locked, the outer shell 2 will not fall off during rotation. Since the installation is relatively closed, water or oil that seeps into the machine can be discharged through the drain port 4 at the bottom of the outer shell 2.

[0035] Upon reaching the warning speed, the gravitational torque is insufficient to provide the torque required for the centrifugal force of eccentric block 1, causing eccentric block 1 to deflect. After deflection, eccentric block 1 rotates around the pivot point 3. At this time, the length of the gravity arm increases, resulting in positive feedback within the rotation range of 0-90°, while the rotation angle of the entire eccentric block 1 obviously will not exceed 90°. Due to the change in the center of gravity, the gravitational torque further decreases, while the required torque further increases, causing eccentric block 1 to experience a positive feedback effect, rapidly deflecting to the outermost side and being restricted by the outer shell 2. The extension distance is determined by the shape of eccentric block 1 and the shape of the outer shell 2. Here, the installation position should be measured according to the actual size of the rotating shaft, and an appropriate installation position should be selected so that the outwardly protruding part of eccentric block 1 can just touch the collision arm 11.

[0036] When it is necessary to reduce the warning speed, the weight 8 is rotated inward, increasing the distance between the center of mass and the fulcrum 3. At this time, the resistance torque of gravity does not change, the lever arm in the centrifugal direction increases, and the centrifugal force required to reach the target decreases, ultimately achieving the effect of reducing the warning speed. The reverse is also true.

[0037] The protruding part of the eccentric block 1 and the collision arm 11 (e.g.) Figure 7 When the eccentric block 1 is touched, it triggers an electrical signal device (such as a PLC controller) to send an electrical signal to stop the rotation of the rotating shaft 15. To ensure the normal operation of the mechanical overspeed device, the eccentric block 1 and the outer casing 2 must not have magnetic properties; therefore, it is recommended that the inner and outer materials be made of brass and stainless steel. Figure 8 This is the overall schematic diagram.

[0038] The present invention uses an eccentric block 1 to gradually increase the centrifugal force, and finally the center of gravity shifts, causing part of the extended pendulum device to collide with the collision arm 11 to generate an action potential and complete the stopping action of the rotating shaft. Compared with the existing mechanical overspeed device, the advantages are: (1) The present invention is caused by the rotation of the eccentric block 1 to contact the collision wall, so the accuracy of mechanical overspeed will not decrease due to the change of spring stiffness; (2) After the eccentric block 1 is fully extended, the present invention will not overextend due to the restriction of the outer shell 2, and will not interfere with other components outside the rotating shaft 15.

[0039] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A center-of-gravity offset type mechanical overspeed device, characterized in that: The device includes a rotating shaft clamp, a pendulum device mounted on the rotating shaft clamp, a counterweight, a collision arm linked to the pendulum device, and an electrical signal device connected to the collision arm. The rotating shaft clamp is used to install on one side of the rotating shaft. The pendulum device includes a housing, a rotating fulcrum located inside the housing, an eccentric block, and a counterweight. The counterweight is detachably installed inside the eccentric block, which can rotate around the rotating fulcrum. When the rotating shaft reaches a warning speed, the eccentric block rotates around the rotating fulcrum and extends out of the housing, where it is restricted. The extended portion of the eccentric block contacts the collision arm, triggering the electrical signal device to send an electrical signal to stop the rotation of the rotating shaft. The eccentric block has a hollow threaded slot, in which a counterweight that moves inward by rotation is installed. The bottom of the housing has a herringbone angle for supporting the eccentric block.

2. The center-of-gravity offset type mechanical overspeed device as described in claim 1, characterized in that: The rotating shaft clamp consists of two semi-circular structures. The two semi-circles are spliced ​​together and installed on one side of the rotating shaft. The pendulum device and the counterweight are respectively installed at the splicing point.

3. The center-of-gravity offset type mechanical overspeed device as described in claim 1, characterized in that: The head of the rotating shaft clamp is fixed to the side plate, and the side plate clamps the outer shell and the counterweight respectively.

4. The center-of-gravity offset type mechanical overspeed device as described in claim 3, characterized in that: The side plate is provided with a herringbone angle to limit the displacement of the eccentric block. There is a gap between the herringbone angle and the eccentric block to ensure that the contact area between the two is small after rotation and to reduce the probability of friction.

5. The center-of-gravity offset type mechanical overspeed device as described in claim 3, characterized in that: The outer shell and side plate are welded to the connecting block, and the connecting block is connected to the rotating shaft clamp by fasteners.

6. The center-of-gravity offset type mechanical overspeed device as described in claim 1, characterized in that: The bottom of the outer casing is provided with a drain port for draining water or oil that has seeped into the machine.

7. The center-of-gravity offset type mechanical overspeed device as described in claim 3, characterized in that: The eccentric block cannot be magnetically attracted to the materials of the outer shell and side plates.

8. The center-of-gravity offset type mechanical overspeed device as described in claim 7, characterized in that: The eccentric block, outer shell, and side plates are made of brass or stainless steel.

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