CN103465220B - The instrument of hollow pins of choosing - Google Patents

Abstract

The invention discloses a tool for extracting a hollow pin, which comprises an elastic cartridge, an expanding core, a pull rod, a sliding hammer and a nut. It is barrel-shaped, and the opening of the elastic cartridge is installed on the lower part of the pull rod. The opening end is provided with a plurality of axial grooves evenly distributed along the circumference. There is a round hole in the center of the upper part of the barrel, and the pull rod passes through the round hole; an expansion core is set inside the elastic card tube, the upper part of the expansion core is cylindrical, and the lower part is a circular frustum shape. The diameter of the lower bottom surface of the circular platform is larger than the inner diameter of the elastic card tube The diameter of the upper bottom surface is smaller than the inner diameter of the elastic cartridge, and the upper end of the expansion core is connected with the lower end of the pull rod through a screw hole. The invention can not only extract positioning pins protruding from parts, but also can extract positioning pins in sinkholes, and can also be used to extract thin-wall sleeves of different depths embedded in parts.

Description

Tool for extracting hollow pins

technical field

The invention relates to the field of mechanical assembly and maintenance, in particular to a tool for extracting hollow pins.

Background technique

At present, when the machine is assembled, positioning pins are usually used for positioning between parts to ensure that the positions of each part are accurate. Dowel pins are generally pressed into one of the parts so that there is an interference fit between them. Extraction of dowel pins is a difficult task when the machine is disassembled.

The existing positioning pin extraction methods are as follows:

1. When the pin hole is a through hole, the positioning pin can be thrown out from the back of the part with a cylindrical tool.

2. If the pin hole is a blind hole, or if it is a through hole but cannot be thrown out smoothly from the back, a screw hole can be processed on the end face of the positioning pin, and then pulled out with a pin pulling tool. For example, the invention "pin puller" whose patent number is 200720110752.9 is used to extract this type of positioning pin.

3. The hollow locating pin can be extracted by using the invention "locating pin extraction tool" whose patent number is 99255287.7. The tool can extract hollow positioning pins, and can also extract solid positioning pins. The principle is to work through the friction force generated by the clamping force of the elastic sleeve acting on the outer surface of the positioning pin cylinder. But there are some problems: 1) The locating pin must be higher than the part by a certain height; 2) The locating pin cannot be pulled out due to slippage during the work of this tool, and the work is unreliable; 3) The working surface of the locating pin is easy to be damaged due to the large clamping force. Hollow dowels can also cause deformation of the pin. Also, the tool is not suitable for larger diameter dowels.

In addition, the mechanical parts are often inserted into the thin-walled sleeve in the hole by interference fit during assembly, and the thin-walled sleeve needs to be taken out during maintenance. For thin-walled sleeves with stress points, tools can be used to pull them out in the axial direction. For thin-walled sleeves without stress points, especially thin-walled sleeves in blind holes, this method cannot be used. In actual production, machining is usually used. The method is to cut off the sleeve, or use a grinding wheel to cut an axial opening groove on the sleeve and take it out. These methods are very easy to damage the bottom hole and cause damage to the part.

Contents of the invention

The technical problem to be solved by the present invention is to provide a tool for extracting hollow pins, which is used for extracting hollow positioning pins in blind holes (or through holes that cannot be smoothly thrown from the back) and thin-walled pins embedded in parts. set.

In order to achieve the above object, the technical solution adopted by the present invention is: the tool for extracting the hollow pin includes a slide hammer, a pull rod and an elastic card cartridge, and the opening of the elastic card cartridge is installed on the lower part of the pull rod downwards, and it is characterized in that: the elastic card cartridge is Barrel-shaped, the opening end is provided with a plurality of axial grooves evenly distributed along the circumference, and the outer edge of the opening end protrudes outwards to form an annular platform with an inverted cone shape as a whole. a circular hole; the elastic cartridge is set with an expanding core, the upper part of the expanding core is cylindrical, and the lower part is truncated circular, the diameter of the lower bottom surface of the circular platform is greater than the inner diameter of the elastic card cartridge, and the diameter of the upper bottom surface is smaller than the inner diameter of the elastic card cartridge. The upper end is connected with the lower end of the pull rod through a screw hole.

The annular platform is 1-2 mm beyond the outer wall of the elastic cartridge.

A nut is threadedly connected to the upper end of the pull rod.

The slide hammer is spindle-shaped with a through hole in the center.

The beneficial effects brought by the invention are: the invention has wide application, not only can extract the positioning pins higher than the parts, but also can extract the positioning pins in the sinkhole, and can also be used to extract thin-walled sleeves of different depths embedded in the parts. The method for extracting the hollow pin is to use the axial force to avoid damage to the surface of the positioning pin by the clamping force. This method is suitable for hollow positioning pins or thin-walled sleeves with a diameter greater than 10mm. This tool is low in manufacturing cost, simple in operation, safe and practical, and is an ideal standing tool for mechanical assembly and maintenance personnel.

Description of drawings

Fig. 1 is a structural schematic diagram of the present invention.

In the figure: 1. Nut, 2. Slide hammer, 3. Pull rod, 4. Elastic cartridge, 5. Hollow positioning pin, 6. Expansion core.

detailed description

The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

As shown in Figure 1, a tool for extracting a hollow pin includes an elastic cartridge 4, a pull rod 3, a slide hammer 2 and a nut 1, the nut 1 is threaded to the upper end of the pull rod 3, and the slide hammer 2 is installed on the pull rod 3, which can be Sliding up and down freely, the elastic cartridge 4 is barrel-shaped, and the opening is installed on the lower part of the pull rod 3. The opening end is provided with a number of axial grooves evenly distributed along the circumference, and the outer edge of the opening end protrudes outward, forming an inverted A conical annular platform, the said annular platform exceeds the outer wall of the elastic cartridge 4 by 1-2mm. There is a circular hole in the center of the upper part of the elastic card cartridge 4, and the pull rod 3 passes through the circular hole; an expansion core 6 is set inside the elastic card cylinder 4, and the upper part of the expansion core 6 is cylindrical, and the lower part is a circular truncated shape. Diameter is greater than elastic card cartridge 4 internal diameters, and upper bottom surface diameter is less than elastic card cartridge 4 internal diameters, and the upper end center of expansion core 6 has a screw hole, links to each other with pull bar 3 lower ends by screw hole. Preferably, the diameter of the lower end of the pull rod 3 is small, and both ends of the pull rod 3 are provided with external threads, and the pull rod 3 is connected with the nut 1 and the expansion core 6 through the external threads. The slide hammer 2 is spindle-shaped with a through hole in the center. The spindle-shaped design is convenient for working hard, and the upper and lower ends of the slide hammer 2 are flat surfaces for applying force to the elastic cartridge 4 or the nut 1.

When working, contact the inverted cone at the opening end of the elastic cartridge 4 with the upper hole of the hollow positioning pin 5, and force it evenly in the axial direction to penetrate into the inner hole of the hollow positioning pin 5 until the elastic card 4 expands and the annular platform hooks the hollow Positioning pin 5 lower end faces. Forcibly lift the pull rod 3, and the expansion core 6 will act on the open end of the elastic card cartridge 4, so that the elastic card cartridge 4 expands, increasing the contact area with the hollow positioning pin 5. Hit the nut 1 on the upper part of the pull rod 3 with the slide hammer 2 so that the hollow positioning pin 5 is subjected to an outward force, and hit it several times until the hollow positioning pin 5 is pulled out. When the annular platform exceeds the outer wall of the elastic cartridge by 1 to 2mm, the tool is convenient for extracting the thin-walled sleeve embedded in the part.

The pin pulling tool can pull out multiple positioning pins at a time, and finally unload the nut 1 and the slide hammer 2, and take out the positioning pins from one end of the pull rod 3. The tool can extract hollow positioning pins within a certain diameter range, and if the diameter exceeds this range, only the corresponding elastic cartridge and expansion core can be replaced.

Claims (3)

1. The tool for extracting the hollow pin includes a sliding hammer (2), a pull rod (3) and an elastic cartridge (4). The elastic cartridge (4) is installed on the lower part of the pull rod (3) with its opening downward. It is characterized in that: The elastic cartridge (4) is barrel-shaped, and its open end is provided with a plurality of axial grooves evenly distributed along the circumference. 4) There is a round hole in the center of the upper part for the pull rod (3) to pass through; the elastic cartridge (4) is fitted with an expanding core (6). The diameter of the lower bottom surface is larger than the inner diameter of the elastic cartridge (4), the diameter of the upper bottom surface is smaller than the inner diameter of the elastic cartridge (4), the upper end of the expansion core (6) is connected to the lower end of the pull rod (3) through a screw hole, and the sliding hammer (2) Installed on the pull rod (3), it can freely slide up and down; the annular platform exceeds the outer wall of the elastic cartridge (4) by 1-2mm. 2. The tool for extracting hollow pins according to claim 1, characterized in that: the upper end of the pull rod (3) is threadedly connected with a nut (1). 3. The tool for extracting hollow pins according to claim 2, characterized in that: the sliding hammer (2) is spindle-shaped with a through hole in the center.