JPS61153021A - Shear pin breakdown detecting mechanism - Google Patents

Abstract

PURPOSE:To detect and alarm breakdown simply and reliably by converting the rotary force into axial thrust force through a tapered cam coupled to a driving member upon breakdown of shear pin. CONSTITUTION:A section 11 is projected into a flange member 3A along the outside of shaft 1A in the center of a driving member or a sprocket 5A. A tapered cam face M is provided in axial direction of said projected section 11 while an annular member 12 having a tapered cam face N engagable with said face M is secured through a screw 13 to the interior of the flange member 3A. While the sprocket 5A is secured through a shear pin 6A and a nut 9 to the flange member 3A. Consequently, upon breakdown of the shear pin 6A, rotation of the tapered cam face M will cause thrust force against the tapered cam face N to move the flange member 3A and an action ring 8A thus to function a limit switch 10.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a shear pin breakage detection mechanism for preventing overload of rotating equipment in all industrial fields.

B. Prior Art and its Problems Conventionally, there have been many requests from the operators of various devices to include an operation detection alarm device for mechanical overload protection bags for rotating bodies of various devices. Conventionally, a type in which a spring is inserted into a shear pin as shown in Fig. 6 is often used. That is, the seven flange-like member 3 is attached to the shaft 1 via the key 2, the movable tin rocket 5 is brought into contact with the seven flange surface of the seven lanzo-like member 3, and the tin rocket is passed through the hole provided in the seven flange surface. Pass the relatively long shear pin 6,
A fill-shaped spring 7 is passed through the shear pin 6, and a disc-shaped action ring 8 is inserted through the outer circumference of the body of the 7 flange-like member 3 and has a through hole for the shear pin 6 in the circular part. , a device in which a nut 9 is screwed onto the tip of a shear pin 6 has been used. In the case of this device, when a mechanical overload occurs, the shear pin 6 is cut near the contact surface between the tin rockets 5 and 7, but when the shear pin 6 is cut, the spring 7 The action ring 8 is pushed by the extension force, which is detected by the limit switch 10vc and an alarm is issued.

However, in this conventional structure, a) when the shear pin breaks, the action ring 8 may become rusted or jammed and may not move with the repulsive force of the shear ring 70;

b) Since the repulsive force of the spring acts constantly on the fractured portion of the shear pin, this creates an additional stress that cannot be ignored, and the shear pin is likely to fracture.

C) When replacing the share bin, it is necessary to extend or contract the spring and install it, which is difficult to do.

No.1 Purpose and outline of the invention The present invention does not have the above-mentioned problems of the conventional device.

It is an object of the present invention to provide a shear bottle breakage detection mechanism that has high accuracy in determining the breaking force of a shear pin and ensures detection and warning after breakage.

In order to achieve the above object, the present invention relates to a mechanism for detecting the breakage of a shear pin by converting the rotational force of the drive member into an axial thrust force using a taper cam connected to the drive member after the shear pin breaks. be.

Embodiment An embodiment of the present invention will be described with reference to FIGS. 1 and 2. In this embodiment, the major difference from the previous conventional example is that the driving member is a protrusion 11 that protrudes into the inside of the flange-like member 3A along the outside of the center part of the 7A. It is to have. The protrusion 11 has a tapered cam surface M on its axial surface, and an annular member 12 having a tapered cam surface N that engages with the tapered cam surface M has a screw 13vc inside the 7 flange-like member 3A above one shaft. More fixed. In this embodiment, sprocket 5
A is fixed by a shear pin 6A and a nut 9 in contact with the 7 run face of the 7 flange member 3A, and a collar 14 is on the shaft on the opposite side from the 7 run face of the sprocket 5A. It is fixed with screws 15.

With this structure, even if the shear pin 6A is broken, its relative position with respect to the shaft will not change. Note that an action ring 8A is fixed to the outer end of the 7 flange-shaped member, and the inside of the 7 lange-shaped member has a long keyway 4A, so when the shear pin is cut, the 5A will rotate idly. However, due to the rotation of the tapered cam surface MO of the protrusion 11 of the X2'' rocket 5A, thrust acts on the tapered cam surface IJiC that is in contact with the same surface M, and as a result, the 7 flange-shaped member 3A moves away from the sprocket 5A in the L direction. At the same time, the action ring 8A also moves in the same direction to push the limit switch 10 and activate any alarm device connected thereto.

Effects of the Invention As described above, the present invention converts the rotational force of the sprocket, etc., into axial movement after the shear pin breaks by having a tapered cam surface connected to the drive member. Since an air contact point is obtained, there is no drawback of the conventional device described above, and since the shear pin does not have any tensile stress due to the spring, the accuracy at the time of breakage is high, and the detection and alarm after the breakage can be reliably performed. It is possible.

[Brief explanation of the drawing]

Fig. 1 is an explanatory sectional view of one embodiment of the present invention, Fig. 2 is a perspective view of a part of the embodiment of Fig. 1, and Fig. 6 is an explanatory sectional view of a conventional example.

Claims (1)

[Claims] A mechanism that detects breakage of the shear pin by converting rotational force into axial thrust using a taper cam connected to the drive member when the shear pin breaks.