CN209868465U

CN209868465U - Synchronous disassembling tool for bicycle crank and crank screw

Info

Publication number: CN209868465U
Application number: CN201920613194.0U
Authority: CN
Inventors: 秦开仲; 徐志刚; 董舒豪; 常艳茹; 苏开远; 朱建峰; 杨得玉
Original assignee: Shenzhen Research Institute Of Shandong University
Current assignee: Shenzhen Research Institute Of Shandong University
Priority date: 2019-04-29
Filing date: 2019-04-29
Publication date: 2019-12-31
Anticipated expiration: 2029-04-29

Abstract

The utility model discloses a synchronous disassembling tool for a bicycle crank and a crank screw, wherein the main body part of the disassembling tool is of a nested structure, and the center of the disassembling tool is a left-handed screw rod with a magnetic suction head; the middle layer is a left-handed internal thread sleeve matched with the screw rod; the outermost layer is a slide rail sleeve provided with a clamping jaw, and a thrust bearing is arranged between the bottom side of the slide rail sleeve and the flange of the left-handed internal thread sleeve. The crank can be disassembled while the crank screw is disassembled by the disassembling tool, tools do not need to be replaced, and the efficiency is high.

Description

Synchronous disassembling tool for bicycle crank and crank screw

Technical Field

The utility model relates to a bicycle extracting tool specifically is a synchronous extracting tool of crank and crank screw.

Background

The traditional bicycle crank is disassembled by screwing out a screw (12) for fixing the crank (11) by a wrench, then ejecting the crank from a middle shaft (13) by using a special puller, and installing the middle shaft on a five-way joint (14). The disadvantage of this approach is that two types of disassembly tools are required to be used for disassembly step by step, the process is cumbersome, and the tools need to be replaced during the disassembly process, which takes a long time.

Disclosure of Invention

The utility model discloses the technical problem that needs to solve is, overcomes the not enough of background art, provides a structure simple relatively reasonable, can dismantle crank and crank screw's instrument simultaneously.

The utility model discloses a main design idea is: firstly, pulling out the crank from the middle shaft by utilizing the linear displacement of the crank screw in the disassembly process, wherein the linear distance moved by the screw is the moving distance of the crank on the middle shaft; secondly, different bicycle structures are often different, but a certain clearance is reserved between at least one side of the cranks on the two sides of the bicycle body and the five-way joint, and the clearance is utilized to realize the action of pulling the cranks, so that the synchronous disassembly is further realized.

The utility model discloses remain traditional, dismantle bearing inner race with lead screw (4) of drawing horse, slide rail sleeve (1) and jack catch (10) structure, jack catch (10) are through fixed block (9), bolt (7) and nut (8) assembly on slide rail sleeve, can follow the slide rail and remove. The specific technical scheme of the disassembling tool is that a left-handed screw (4) is adopted, a magnetic suction head (5) is welded at the lower end of the left-handed screw, and a replaceable disassembling head (6) which can be replaced according to the size and the shape of a crank screw is matched and sleeved on the left-handed screw. The screw rod is matched with the left-handed internal thread sleeve (3), and the sliding rail sleeve (1) is sleeved on the left-handed internal thread sleeve (3) in a clearance fit mode. A thrust bearing (2) is arranged between the sliding rail sleeve (1) and the left-handed inner thread sleeve flange (3-1), so that the plane friction between the sliding rail sleeve and the left-handed inner thread sleeve can be effectively reduced, and the disassembly effect is prevented from being influenced by relative rotation between the screw rod and the left-handed inner thread sleeve in the disassembly process.

The utility model discloses the structure is simple relatively, and is comparatively reasonable, can dismantle crank and crank screw simultaneously, has the higher advantage of dismantlement efficiency, is the innovation to bicycle extracting tool.

Drawings

Fig. 1 is an isometric view of the removal tool.

Fig. 2 is an exploded view of the removal tool.

FIG. 3 is an isometric view of a bicycle crank mounting location.

Fig. 4 is a schematic view of the disassembly step 1.

Fig. 5 is a schematic view of the disassembling step 2.

Fig. 6 is a schematic view of the disassembling step 3.

Fig. 7 is a schematic view of the left-hand lead screw acting on the crank screw when the jaws are fixed.

Fig. 8 is a schematic view of the effect of the right-handed screw on the crank screw when the jaws are secured.

FIG. 9 is a schematic view of the left-handed female socket being forced upon removal of the crank screw and crank.

Detailed Description

The present invention will be further explained with reference to the accompanying drawings.

Removal tool example 1. Referring to fig. 1 and 2, the disassembling tool of the embodiment adopts a nested structure, and the center of the disassembling tool is a left-handed screw rod (4) with a magnetic suction head (5); the middle layer is a left-handed internal thread sleeve (3) matched with the screw rod, and the sleeve is provided with a thrust bearing (2) mounting position, namely a flange (3-1) and an outer hexagonal wrench position (3-2); the outmost layer is a sliding rail sleeve (1) provided with a clamping jaw (10).

Example 1 was used. See fig. 4, 5, 6 for disassembly steps 1, 2, 3, respectively. Step 1, opening a clamping jaw, and aligning a disassembling head to a crank screw; step 2, clamping the tail end of the jaw into a gap between the crank and the five-way, and then screwing the left-handed internal thread sleeve in the direction shown in the figure 5 to fix the jaw; and 3, screwing the left-handed screw rod in the direction shown in the figure 6, screwing out the crank screw, and pulling the slide rail of the slide rail sleeve outwards to slightly apply force if the crank is not completely pulled out, so that the disassembly can be finished.

To explain the reason for adopting the left-handed screw rod in detail, the following supplements are made:

comparative example 1. Referring to fig. 7 and 8, when a left-handed screw rod (fig. 7) is adopted, the internal thread sleeve (3) is screwed in the direction shown in the figure to drive the sliding rail sleeve (1) and the clamping jaws (10) to move upwards(s)₁). Because friction exists between the internal thread sleeve (3) and the screw rod (4) when the internal thread sleeve rotates, the screw rod is also subjected to a moment in the same direction as the M, and the direction of the moment makes a crank screw have a screwing tendency(s)₂) And the clamping jaw is matched with the upward movement of the sliding rail sleeve to achieve the effect of fixing the clamping jaw. When a right-handed screw is used (fig. 8), when the torque applied to the screw is large, the crank screw can be screwed out(s)₂) The jaw cannot be fixed.

Force application example 1. See fig. 9, a moment M in the direction shown is applied to the screw during the disassembly process. In an ideal state, when a left-handed screw rod is adopted, the static friction coefficient is far greater than the rolling friction coefficient, so the maximum static friction force f of the screw rod (4) on the inner thread sleeve (3)₁Far greater than the friction force f of the thrust bearing (2) to the internal thread sleeve (3)₂Therefore, the internal thread sleeve (3) can rotate along with the screw rod (4) to transmit the linear displacement of the crank screw to the crank, so as to realize synchronous disassembly; in practical use, due to factors such as assembly error, the sliding rail sleeve (1) is very likely to generate additional friction force f to the internal thread sleeve (3)₃Let f be₂+f₃＞f₁The inner thread sleeve (3) has a tendency of moving upwards, so that the slide rail sleeve (1) and the clamping jaw (10) also have a tendency of moving upwards, and the clamping jaw (10) is more reliably fixed in the dismounting process. Similarly, if a right-handed screw rod is adopted, the stress condition of the internal thread sleeve (3) in the disassembly process is consistent with that in the left-handed process, but the internal thread sleeve tends to move downwards or even moves downwards under the action of the force, so that the disassembly process tends to be unreliable.

Claims

1. The utility model provides a synchronous extracting tool of bicycle crank and crank screw, includes slide rail sleeve (1), lead screw (4), jack catch (10), its characterized in that the lead screw adopt the levogyration external screw thread to have the levogyration internal thread sleeve (3) of complex with it.

2. The removal tool according to claim 1, characterized in that the lower end of the spindle (4) is provided with a magnetic suction head (5) and a matched replaceable removal head (6).

3. The removal tool according to claim 1, wherein the left-hand internally threaded sleeve (3) has a flange (3-1) at its lower end.

4. A removal tool according to claim 1 or 3, characterized in that the upper part of the left-handed internally threaded sleeve (3) is externally hexagonal (3-2).

5. A removal tool according to claim 1 or 3, characterized in that a thrust bearing (2) is provided between the slide sleeve (1) and the left-hand internally threaded sleeve flange (3-1).