A positioning fixture for circuit board mounting

Abstract

A positioning fixture for circuit board mounting includes a substrate, on which a circuit board is placed. Side clamps abut against each side clamp, and guide rods are provided at both ends of the side clamps. A slotted hole is formed in the substrate, through which the guide rods pass. The side clamps are located on the upper side of the substrate. A lower plate is threaded to the lower end of each pair of guide rods. A vertical plate is provided on the lower plate, and a pair of guide rods passes through the vertical plate. A mounting seat is provided on the inner end of each guide rod, and the mounting seat is screwed to the lower side of the substrate. A spring is sleeved on the guide rod, located between the mounting seat and the vertical plate. An eccentric disc is tangent to the outer wall of the lower plate, and a rotating shaft is eccentrically mounted on the eccentric disc. A bearing seat is mounted on the rotating shaft, and the bearing seat is screwed to the substrate. This invention replaces point-to-surface contact positioning with surface contact clamping, improving the positioning effect of the circuit board and avoiding unevenness of the circuit board, while also facilitating clamping and positioning operations.

Description

Technical Field

[0001] This utility model relates to control board processing technology, and in particular to a positioning fixture for circuit board mounting. Background Technology

[0002] In the fabrication of control boards, surface mount technology (SMT) is used, requiring the precise placement of microelectronic components onto predetermined pad positions. Traditional placement fixtures often use mechanical clamps or vacuum suction to fix the circuit board, which can easily lead to localized substrate deformation, causing micron-level height deviations between the placement area and the nozzle's moving plane. When the pick-and-place machine is mounting multi-chip modules (MCMs) or 01005-level micro-components, this flatness deviation can result in defects such as component tilting and uneven solder paste printing. Statistics show that these problems cause SMT production line yield losses of 1.2%-3.5%. Current improvement solutions use double-sided tape to temporarily fix the substrate, which can maintain the flatness of the processing surface, but there are problems such as difficulty in removing the substrate, adhesive residue affecting the contact of ICT test probes, and the time taken for a single positioning increases by more than 35 seconds, seriously affecting the cycle efficiency of high-mix assembly lines. Utility Model Content

[0003] This utility model provides a positioning fixture for board mounting, which solves the shortcomings of the prior art and addresses the problems of inconvenient clamping and inability to ensure a flat processing surface after clamping when mounting components on the board. It has strong practicality.

[0004] In order to achieve the purpose of this utility model, the following technology is proposed to be adopted:

[0005] A positioning fixture for circuit board mounting includes a substrate, on which a circuit board is placed. Side clamps abut against each of the four side walls of the circuit board. Guide rods are provided at both ends of the side clamps. Multiple slotted holes are formed on the substrate, through which the guide rods pass. The side clamps are located on the upper side of the substrate. A lower plate is threaded to the lower end of each pair of guide rods. A vertical plate is provided on the lower plate, and a pair of guide rods passes through the vertical plate. A mounting seat is provided on the inner end of each guide rod, and the mounting seat is installed on the lower side of the substrate by screws. A spring is sleeved on the guide rod, located between the mounting seat and the vertical plate. An eccentric disc is tangent to the outer wall of the lower plate, and a rotating shaft is eccentrically mounted on the eccentric disc. A bearing seat is provided on the rotating shaft, and the bearing seat is installed on the substrate by screws. This solution uses a long strip-shaped side clamp to position and hold the circuit board. First, it ensures that each side wall of the circuit board receives equal force to avoid excessive force on one side, which could cause warping of the circuit board's processing surface. Second, it facilitates clamping operations, as clamping can be achieved simply by rotating the pivot. Finally, the long strip-shaped side clamp replaces the existing point contact with a surface contact method, which ensures the uniformity of the clamping and positioning force during clamping.

[0006] Furthermore, to facilitate the installation and connection of the guide rod, an upper cap is provided at the upper end of the guide rod, and the upper end of the guide rod is connected to the side clamp plate by a thread.

[0007] Furthermore, to facilitate synchronous positioning of the upper side of the circuit board and avoid unevenness, a vertical rod is threaded onto the upper cap. A limiting cap is provided at the upper end of the vertical rod. A pressure plate is fitted onto each pair of vertical rods. An upper clamping plate is bent downward at the inner end of the pressure plate. The lower end of the upper clamping plate acts on the circuit board. An upper top spring is fitted onto the vertical rod. The upper top spring is located between the pressure plate and the side clamping plate. An upper extension sleeve is fixed on the pressure plate. A protrusion is formed at the upper end of the upper extension sleeve. A rotating shaft passes through the upper extension sleeve. A lower pressing protrusion is provided at the upper end of the rotating shaft. The outer periphery of the lower pressing protrusion acts on the upper end of the upper extension sleeve. The axial direction of the rotating shaft is perpendicular to the axial direction of the lower pressing protrusion.

[0008] Furthermore, in order to facilitate the downward action of the pressing rod on the protrusion so that the pressure plate moves downward, the protrusion is designed with a V-shaped structure.

[0009] Furthermore, in order to facilitate the rotation of the shaft, a rotating lever is provided on the shaft.

[0010] Furthermore, in order to flexibly perform the rotation and positioning operations of the shaft, the pressing protrusion is rotatably mounted on the shaft.

[0011] The advantages of the above technical solution are:

[0012] This invention replaces the point-to-surface contact positioning method with a surface contact clamping method, which improves the positioning effect of the circuit board and avoids the problem of unevenness of the circuit board, while also facilitating the clamping and positioning operation. Attached Figure Description

[0013] To make the objectives, technical solutions, and advantages of this utility model clearer, the following will provide a further detailed description of this utility model in conjunction with the accompanying drawings.

[0014] Figure 1 A three-dimensional structure of one embodiment is shown. Figure 1 .

[0015] Figure 2 A magnified view of point A is shown.

[0016] Figure 3 A three-dimensional structure of one embodiment is shown. Figure 2 .

[0017] Figure 4 A magnified view of point B is shown. Detailed Implementation

[0018] like Figures 1-4As shown, a positioning fixture for circuit board mounting includes a substrate 1, which is fixedly mounted on a mounting processing platform by screws or the like. The circuit board is placed on the substrate 1, and side clamps 25 are abutted on the four side walls of the circuit board. Guide rods 2 are provided at both ends of the side clamps 25, and upper caps 26 are provided at the upper ends of the guide rods 2. The upper ends of the guide rods 2 are connected to the side clamps 25 by threads. The substrate 1 has multiple slotted holes 10, and guide rods 2 pass through the slotted holes 10. The side clamping plate 25 is located on the upper side of the substrate 1. The lower end of each pair of guide rods 2 is connected to a lower plate 20 by threads. The lower plate 20 is provided with a vertical plate 21. A pair of guide rods 22 are passed through the vertical plate 21. The inner end of the guide rod 22 is provided with a mounting seat 23. The mounting seat 23 is installed on the lower side of the substrate 1 by screws. A spring 24 is sleeved on the guide rod 22. The spring 24 is located between the mounting seat 23 and the vertical plate 21. The outer wall of the lower plate 20 is tangent to an eccentric disk 37. The eccentric disk 37 is eccentrically provided with a rotating shaft 34. The rotating shaft 34 is provided with a bearing seat 33. The bearing seat 33 is installed on the substrate 1 by screws.

[0019] A vertical rod 27 is threadedly connected to the upper cap 26. A limit cap is provided at the upper end of the vertical rod 27. A pressure plate 29 is fitted on each pair of vertical rods 27. An upper clamping plate 30 is bent downward at the inner end of the pressure plate 29. The lower end of the upper clamping plate 30 acts on the circuit board. An upper top spring 28 is fitted on the vertical rod 27. The upper top spring 28 is located between the pressure plate 29 and the side clamping plate 25. An upper extension sleeve 31 is fixed on the pressure plate 29. A protrusion 32 is formed at the upper end of the upper extension sleeve 31. The protrusion 32 has a V-shaped structure. A rotating shaft 34 passes through the upper extension sleeve 31. A rotating lever 36 is provided on the rotating shaft 34. A lower pressing protrusion 35 is provided at the upper end of the rotating shaft 34. The outer periphery of the lower pressing protrusion 35 acts on the upper end of the upper extension sleeve 31. The axial direction of the rotating shaft 34 is perpendicular to the axial direction of the lower pressing protrusion 35. Preferably, the lower pressing protrusion 35 is rotatably mounted on the rotating shaft 34.

[0020] When applying the circuit board, the operator places the circuit board on the substrate 1 and places it between the side clamps 25.

[0021] Then, the operator rotates the rotating shaft 34 by rotating the lever 36. The rotation of the lever 36 will drive the pressing protrusion 35 on it to rotate around the rotating shaft 34. When the pressing protrusion 35 rotates, it first acts on the upper end plane of the upper extension sleeve 31. During this process, the rotating shaft 34 will drive the eccentric disk 37 to rotate. As the eccentric disk 37 rotates, the lower plate 20 and the side clamping plate 25 indirectly connected to it will move inward, so that the side clamping plate 25 acts on the circuit board. Of course, the side clamping plate 25 may not contact the circuit board when it moves inward for the first time. In subsequent operations, each side wall of the circuit board will contact the side clamping plate 25. In order to facilitate positioning, the two adjacent side clamping plates 25 can be moved inward first, and then the other two side clamping plates 25 can be positioned and clamped. When the side clamp 25 moves closer to the circuit board, the downward pressing protrusion 35 will also move toward the protrusion 32 and act on the end face of the protrusion 32, thereby causing the upper clamp 30 located above the circuit board to move downward and causing the lower end of the upper clamp 30 to act on the upper wall of the circuit board, and finally complete the positioning operation of the circuit board.

[0022] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Obviously, those skilled in the art can make various modifications and variations to the present utility model without departing from the spirit and scope of the present utility model.

Claims

1. A positioning fixture for mounting circuit boards, characterized in that, The circuit includes a substrate (1), a circuit board placed on the substrate (1), and side clamps (25) abutting against the four side walls of the circuit board. Guide rods (2) are provided at both ends of the side clamps (25). Multiple slotted holes (10) are opened on the substrate (1), and the guide rods (2) pass through the slotted holes (10). The side clamps (25) are located on the upper side of the substrate (1). A lower plate (20) is threaded to the lower end of each pair of guide rods (2). A vertical plate (21) is provided on the lower plate (20), and a guide rod (21) passes through the vertical plate (21). For the guide rod (22), the inner end of the guide rod (22) is provided with a mounting seat (23). The mounting seat (23) is installed on the lower side of the base plate (1) by screws. A spring (24) is sleeved on the guide rod (22). The spring (24) is located between the mounting seat (23) and the vertical plate (21). The outer wall of the lower plate (20) is tangent to an eccentric disk (37). A rotating shaft (34) is eccentrically provided on the eccentric disk (37). A bearing seat (33) is provided on the rotating shaft (34). The bearing seat (33) is installed on the base plate (1) by screws.

2. The positioning fixture for circuit board mounting according to claim 1, characterized in that, The upper end of the guide rod (2) is provided with an upper cap (26), and the upper end of the guide rod (2) is connected to the side clamp (25) by a thread.

3. The positioning fixture for circuit board mounting according to claim 2, characterized in that, A vertical rod (27) is connected to the upper cap (26) by a thread. A limit cap is provided at the upper end of the vertical rod (27). A pressure plate (29) is fitted on each pair of vertical rods (27). An upper clamping plate (30) is bent downward at the inner end of the pressure plate (29). The lower end of the upper clamping plate (30) acts on the circuit board. An upper top spring (28) is fitted on the vertical rod (27). The upper top spring (28) is located between the pressure plate (29) and the side clamping plate (25). An upper extension sleeve (31) is fixed on the pressure plate (29). A protrusion (32) is formed at the upper end of the upper extension sleeve (31). A rotating shaft (34) passes through the upper extension sleeve (31). A lower pressing protrusion (35) is provided at the upper end of the rotating shaft (34). The outer periphery of the lower pressing protrusion (35) acts on the upper end of the upper extension sleeve (31). The axial direction of the rotating shaft (34) is perpendicular to the axial direction of the lower pressing protrusion (35).

4. The positioning fixture for circuit board mounting according to claim 3, characterized in that, The convex part (32) has a V-shaped structure.

5. The positioning fixture for circuit board mounting according to claim 3, characterized in that, A rotating lever (36) is provided on the rotating shaft (34).

6. The positioning fixture for circuit board mounting according to claim 3, characterized in that, The downward pressing protrusion (35) is rotatably mounted on the rotating shaft (34).

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