Auxiliary jig for small-size plate

Abstract

The utility model relates to the field of production jigs, in particular to an auxiliary jig for a small-size plate. A plurality of cells are arranged, and a plurality of limiting steps are arranged in the cells, so that a small-size plate is limited in the cells, and the problem of large position deviation or front-back overturning of the small-size plate during surface treatment such as OSP, silver melting and tin melting is avoided; the positions of the first limiting steps and the second limiting steps of the cells can be arranged according to weight configuration and plate types of different small-size plates, damaged parts can be replaced through the dismounting parts, the service life of the whole jig is prolonged, and therefore the production cost is reduced.

Description

Technical Field

[0001] The utility model relates to the field of PCB production jigs, in particular to an auxiliary jig for small-size boards. Background Art

[0002] If the small-sized boards after forming need to undergo surface treatments such as OSP, silver plating, and tin plating, they are often limited by the process capabilities of the surface treatment equipment itself, resulting in abnormalities such as stuck boards, dropped boards, and stacked boards when the boards that are too small are directly surface treated, making it impossible to perform effective surface treatment. In the prior art, such small-sized boards need to be glued before surface treatment. After the small-sized boards are arranged front, back, left, and right in sequence, they are taped together to form a relatively large whole, and then surface treated before the tape is torn off. However, such an operation method wastes manpower or material costs, has low production efficiency, high quality risks, and cannot receive orders when the area to be surface treated is too large to be glued for production. Some other existing technologies also use some mesh auxiliary fixtures for fixing, but most of these mesh auxiliary fixtures are for fixing large or medium-sized boards. When the size of the board is relatively small, these auxiliary fixtures cannot fix the small-sized board, resulting in surface treatments such as OSP, silver plating, and tin plating, which may cause the board to get stuck, fall off, or overlap. In addition, since most of the auxiliary fixtures are integrally formed, when some mesh units are damaged or cracked, they cannot be disassembled and replaced, which will eventually make the entire fixture scrapped, resulting in unnecessary increase in production costs. Utility Model Content

[0003] In order to solve these problems, the utility model proposes an auxiliary fixture for small-sized boards. The fixture sets cells so that the small-sized boards can be exactly limited in the cells, thereby fixing the small-sized boards to prevent the small-sized boards from being offset and flipped forward and backward during surface treatments such as OSP, silver plating, and tin plating. In addition, through the detachable cell form, the entire auxiliary fixture can be replaced for damaged cells to prevent the entire auxiliary fixture from being scrapped, thereby reducing production costs, and also abandoning the method of fixing small-sized boards with glue, reducing cost waste, increasing production costs, and improving quality.

[0004] The purpose of the utility model is achieved through the following technical solutions:

[0005] An auxiliary fixture for a small-sized plate comprises a main frame, the main frame is enclosed by two first outer frames and two second outer frames, the main frame is provided with a plurality of connecting plates, both ends of the connecting plates are respectively connected to the two first outer frames, and the connecting plates are arranged in parallel with the second outer frames;

[0006] At least one mounting cell is arranged between adjacent connecting plates and between a connecting plate and an adjacent second outer frame, and the mounting cell is provided with a plurality of limiting steps for placing a small-sized PCB board.

[0007] In some embodiments, a jig outer frame is formed by a first outer frame and a second outer frame, and the outer frame is isolated into multiple rectangular spaces by a connecting plate, and multiple cells are arranged at intervals in the rectangular spaces, so that the cells in the entire jig are arranged neatly and it is convenient to fill small-sized boards. Multiple limiting steps are provided in the cells, and the limiting steps form a limiting layer surrounding the inner circumference of the cells in the entire cells. The small-sized boards are placed in the limiting layer to prevent the small-sized boards from being limited in the limiting layer, causing problems such as board jamming, board falling, and board stacking.

[0008] In some embodiments, a mounting plate is connected between adjacent connecting plates and between the connecting plates and the adjacent second outer frames. The mounting plate isolates each cell. The cells are arranged step by step between the connecting plates and the second outer frame. The mounting plate divides a plurality of cells, so that the cells are arranged at regular intervals. This allows operators or production machinery to place small-sized boards more efficiently during production. By designing the cells to be neatly arranged, the efficiency of surface treatments such as OSP, silver plating, and tin plating can be effectively improved, thereby reducing the waste of labor costs.

[0009] In some embodiments, multiple limiting steps are arranged along the inner circumference of the installation cell, each edge in the cell forms a limiting step, each limiting step is connected head to tail inside the cell, and finally forms a limiting layer on the inner circumference of the cell, and the limiting layer is used to limit the small-sized board.

[0010] In some embodiments, the limiting step includes a plurality of first limiting steps, and the plurality of first limiting steps are respectively arranged on two opposite sides of the installation unit cell; the first limiting step is arranged on the opposite side, and the limiting step is formed by the upper surface of the first limiting step and the side wall of the unit cell where the first limiting step is located, and the first limiting step is distributed on one side where the mounting plate is connected to the unit cell. According to the shape of the small-size plate to be fixed and the weight distribution on the plate, the number and position of the first limiting steps are set to provide longitudinal limitation for the small-size plate.

[0011] Optionally, the first limiting step may be set to have a length that is the same as the width of a side wall of the cell on which it is located.

[0012] In some embodiments, the limiting step includes a plurality of second limiting steps, and the plurality of second limiting steps are respectively arranged on two opposite sides of the installation unit cell; the second limiting step is not arranged coplanarly with the first limiting step, the first limiting step is arranged on the opposite side, and the limiting step is formed by the upper surface of the second limiting step and the side wall of the unit cell where the second limiting step is located, and the second limiting step 220 is distributed on the side where the first outer frame or the connecting plate is connected to the unit cell. According to the shape of the small-size plate to be fixed and the weight distribution on the plate, the number and position of the second limiting steps are set to provide lateral limitation for the small-size plate, and the second limiting step and the first limiting step are arranged on different surfaces.

[0013] Optionally, the second limiting step 220 may be set to have a length that is the same as the width of a side wall of the cell where it is located.

[0014] In some embodiments, the heights of the first limiting step and the second limiting step are smaller than the inner circumference height of the installation unit cell; the first limiting step and the second limiting step have the same horizontal height, and the first limiting step and the second limiting step are arranged below the side wall to prevent uneven surface treatment such as OSP, silver plating, and tin plating when placing small-sized boards.

[0015] In some embodiments, two first protrusions are provided in the cell, and the first protrusion is provided at the intersection where the cell is connected to the connecting plate, or at the intersection where the cell is connected to the second outer frame, and the first protrusions are on the same side in the cell, and the first protrusion consists of a first part and a second part. The first protrusion is used to limit the entire plate shape of the small-size plate on which the cell is placed, and the cell and the overall frame are disassembled and assembled through the first part and the second part of the first protrusion.

[0016] In some embodiments, the cell consists of a fixed part and a disassembly part, the fixed part is fixed on the main frame, and the disassembly part is disassembled from the fixed part; the fixed part of the cell is integrally arranged on the entire main frame during the production of the jig; and the disassembly part is produced separately, and can be set in steps according to the weight of a specific small-size plate type, with a specific first limit step and a second limit step; and since the disassembly part is the part that contacts the process and the plate type, its damage frequency is high, and the disassembly part can be set to replace the damaged part, thereby preventing the entire main frame from being scrapped and improving the life of the entire main frame.

[0017] In some embodiments, the fixing portion is arranged outside the cell, and a second part of the first protrusion is arranged on the fixing portion, a fourth fixing point and a fifth fixing point are arranged on the second part, and a sixth fixing point is arranged on the opposite side of the side where the first part of the first protrusion of the cell is located, and the sixth fixing point is used to fix the rear of the cell.

[0018] In some embodiments, the disassembly part is embedded in the inner side of the fixing part, and a first part of a first protrusion is provided on the disassembly part, a first fixing point and a second fixing point are provided on the first part, and a third fixing point is provided on the opposite side of the side where the first part of the first protrusion of the cell is located. The fourth fixing point, the fifth fixing point and the sixth fixing point are respectively fixed to the first fixing point, the second fixing point and the third fixing point, and the fixing part and the disassembly part are fixed by the relative fixation of the three fixing points.

[0019] The auxiliary fixture of a small-sized plate of the utility model has the following effects:

[0020] By setting a plurality of cells and a plurality of limit steps in the cells, the small-sized boards are limited within the cells, so that the small-sized boards will not get stuck, fall off, overlap, or other problems when undergoing surface treatments such as OSP, silver plating, and tin plating. A disassembly part is provided in the cell, so that the positions of the first limit step and the second limit step can be set according to the weight configuration and plate type of different small-sized boards, and the damaged parts can be replaced through the disassembly part, thereby improving the life of the overall fixture and reducing the production cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a three-dimensional diagram of the utility model;

[0022] Figure 2 A three-dimensional diagram of a cell of the present utility model;

[0023] Figure 3 It is a cell exploded diagram of the utility model;

[0024] Reference numerals:

[0025] 100, main frame; 110, first outer frame; 120, second outer frame; 130, connecting plate; 140, mounting plate; 150, unit cell; 151, fixing part; 152, disassembling part;

[0026] 200, limiting step; 210, first limiting step; 220, second limiting step;

[0027] 300, first protrusion; 310, first part; 311, first fixing point; 312, second fixing point; 313, third fixing point; 320, second part; 321, fourth fixing point; 322, fifth fixing point; 323, sixth fixing point; DETAILED DESCRIPTION

[0028] It should be noted that, in the absence of conflict, the embodiments of the present invention and the technical features in the embodiments can be combined with each other, and the detailed description in the specific implementation method should be understood as an explanation of the purpose of the present invention and should not be regarded as an improper limitation on the present invention.

[0029] In order to make the purpose, technical solution and advantages of the embodiment of the utility model clearer, the specific technical solution of the utility model will be further described in detail below in conjunction with the drawings in the embodiment of the utility model. The following embodiments are used to illustrate the utility model, but are not used to limit the scope of the utility model.

[0030] In the embodiments of the present invention, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of the present invention, unless otherwise specified, the meaning of "multiple" is two or more.

[0031] In addition, in the embodiments of the present invention, directional terms such as "up", "down", "left" and "right" are defined relative to the orientation of the components in the drawings. It should be understood that these directional terms are relative concepts. They are used for relative description and clarification, and they may change accordingly according to the changes in the orientation of the components in the drawings.

[0032] In the embodiments of the present invention, unless otherwise clearly specified and limited, the term "connection" should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection or an indirect connection through an intermediate medium.

[0033] In the embodiments of the present invention, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the presence of other identical elements in the process, method, article or device comprising the element.

[0034] In the embodiments of the present invention, words such as "exemplary" or "for example" are used to indicate examples, illustrations or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of the present invention should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary" or "for example" is intended to present the related in a specific way.

[0035] Embodiment 1:

[0036] In other embodiments, Figures 1 to 3 As shown, an auxiliary fixture for a small-sized board includes a main frame 100, which is enclosed by two first outer frames 110 and two second outer frames 120. The main frame 100 is provided with a plurality of connecting plates 130, and both ends of the connecting plates 130 are respectively connected to the two first outer frames 110, and the connecting plates 130 are arranged in parallel with the second outer frames 120;

[0037] At least one mounting cell 150 is disposed between adjacent connecting plates 130 and between a connecting plate 130 and an adjacent second outer frame 120 , and the mounting cell 150 is provided with a plurality of limiting steps 200 for placing a small-sized PCB board.

[0038] Among them, the first outer frame 110 and the second outer frame 120 form a jig outer frame, and a plurality of connecting plates 130 are arranged in the outer frame at the same interval, and the connecting plates 130 extend from the first outer frame 110 on one side parallel to the second outer frame 120 to the first outer frame 110 on the other side, thereby cutting the inner space of the outer frame to form a plurality of rectangular longitudinal grooves; the cells 150 are arranged between the longitudinal grooves at the same intervals, and are formed in the outer frame, and the cells 150 are aligned up and down, left and right, and arranged regularly. In addition, a plurality of limiting steps 200 are arranged in the cells 150, and the side walls of the cells 150 form a space limiting layer at the upper part of the cells 150, so that the small-sized board can be limited and moved in the limiting layer, and the horizontal plane of the small-sized board is parallel to the plane of the outer frame, or flush with the plane of the outer frame, so that the entire small-sized board can not move a large distance or flip the plane during the surface treatment processes such as OSP, silver, and tin, and the size of the cell is 0.1-0.3mm larger than the small-sized board.

[0039] Embodiment 2:

[0040] Based on Example 1, Figure 2 As shown, this example further optimizes the limiting step 200 of the unit cell 150;

[0041] As shown in the figure, in another embodiment, a mounting plate 140 is further connected between adjacent connecting plates 130 and between the connecting plates 130 and the adjacent second outer frame 120. The mounting plate 140 is arranged horizontally, extending from the second outer frame 120 on one side to the second outer frame 120 on the other side and parallel to the first outer frame 110. The mounting plate 140 isolates each cell 150. The cells 150 are arranged stepwise between the connecting plates 130 and the second outer frame 120, and a plurality of cells 150 are divided by the mounting plate 140 and the connecting plates 130. Thus, the cells 150 are arranged regularly at intervals, which enables operators or production machinery in production to place small-sized boards more efficiently.

[0042] In another embodiment, a plurality of limiting steps 200 are arranged along the inner circumference of the installation unit cell 150, the upper edge of the unit cell 150 is the limiting step 200, the length of the limiting step 200 is the length of one side of the unit cell 150 where the limiting step 200 is located, and the limiting step 200 is a space formed by the upper surface of the first limiting step 210 and the second limiting step 220 and the part of the side wall of the unit cell 150 on the upper surface of the first limiting step 210 and the second limiting step 220. Inside the side wall of the unit cell 150, each limiting step 200 is connected head to tail inside the unit cell 150, and finally forms a limiting layer on the inner circumference of the unit cell 150, and the limiting layer is used to limit the small-sized board.

[0043] In some other preferred embodiments, the limiting step 200 includes a plurality of first limiting steps 210, and the first limiting steps 210 are respectively arranged on two opposite sides of the installation unit cell 150, and the two sides are formed by the upper surface of the first limiting step 210 and the side wall of one side of the unit cell 150 where the first limiting step 210 is located above the upper surface of the first limiting step 210, and the first limiting step 210 is distributed on the side where the mounting plate 140 is connected to the unit cell 150, and the second outer frame 12 is parallel to the side along the second outer frame 12 0, the extension length is less than half of the side where the cell 150 is connected to the connecting plate 130 or the second outer frame 120, and its thickness is half of the inner wall of the cell 150; and the first limiting step 210 is fixed according to the shape of the small-sized plate and the weight distribution on the plate as required; the first limiting step 210 can be set to a mirror position on both sides, or asymmetrically, and the number of the first limiting steps 210 on both sides is the same, or the number of the first limiting steps 210 on both sides is inconsistent, and the first limiting step 210 provides lateral limitation for the small-sized plate.

[0044] Optionally, the first limiting step 210 may be set to have a length that is the same as the width of a side wall of the cell 150 where it is located.

[0045] In other embodiments, the limiting step 200 includes a plurality of second limiting steps 220, and the plurality of second limiting steps 220 are respectively arranged on two opposite side surfaces of the installation unit cell 150; the second limiting step 220 is not arranged coplanarly with the first limiting step 210, and the limiting step 200 is formed by the upper surface of the second limiting step 220 and the side wall of one side of the unit cell 150 where the second limiting step 220 is located, and the side wall above the upper surface of the second limiting step 220, and the second limiting step 220 is distributed between the connecting plate 130 or the second outer frame 120 and the unit cell 150. One side of the connection extends from this side in a direction parallel to the first outer frame 110, and the extension length is less than half of the unit cell 150 and the connection side, and its thickness is half of the inner wall of the unit cell 150; and the first limiting step 210 is fixed according to the shape of the small-sized plate and the weight distribution on the plate as required; the first limiting step 210 can be set to a mirror position on both sides, or asymmetrically, and the number of first limiting steps 210 on both sides is the same, or the number of first limiting steps 210 on both sides is inconsistent, and the first limiting step 210 provides longitudinal limitation for the small-sized plate.

[0046] Optionally, the second limiting step 220 may be set to have a length that is the same as the width of a side wall of the cell 150 where it is located.

[0047] In other embodiments, the height of the first limiting step 210 and the second limiting step 220 are less than the height of the inner circumference of the installation unit cell 150; the first limiting step 210 and the second limiting step 220 have the same horizontal height, and the thickness is half of the thickness of the side wall of the unit cell 150; the first limiting step 210 and the second limiting step 220 are below the upper surface of the unit cell 150, and the height must be kept consistent to prevent the small-sized board from having an uneven surface when placed, thereby causing uneven printing and painting processes.

[0048] Embodiment 3:

[0049] Based on Example 1, Figure 3 As shown, this embodiment further defines the detachable portion 152 of the auxiliary fixture;

[0050] In other embodiments, two first protrusions 300 are provided in the cell 150. The first protrusion 300 is provided at the intersection where the cell 150 is connected with the connecting plate 130, or at the intersection where the cell 150 is connected with the second outer frame 120. The first protrusion 300 is rectangular or square and extends from the intersection toward the center of the cell 150. The extended length of the first protrusion 300 is less than half of the length of the minimum side wall of the cell 150. The first protrusion 300 is on the same side where the cell 150 is connected to the connecting plate 130 or the second outer frame 120, and there are only two first protrusions 300 in the same cell 150; the first protrusion 300 is composed of a first part 310 and a second part 320, wherein the first part 310 is above the second part 320, the second part 310 is arranged on the theme frame, and is formed integrally with the frame, and the first part 310 and the second part 320 can be completely overlapped and placed; the two first parts 310 and the second part 320 are respectively provided with through holes, and when the first part 310 and the second part 320 overlap, the through holes can just correspond to form screw grooves for screw fixing. The first protrusion 300 is used to limit the entire plate shape of the small-sized plate on which the cell 150 is placed, and the cell 150 and the overall frame are disassembled and assembled through the first part 310 and the second part 320 of the first protrusion 300.

[0051] In other embodiments, the cell 150 is composed of a fixing part 151 and a disassembly part 152. The fixing part 151 is fixed on the main frame 100, and the disassembly part 152 is disassembled from the fixing part 151. During installation, the disassembly part 152 is installed in the fixing part 151 to form the cell 150, which is installed and disassembled by flat head screws. The flat head screws need to be completely immersed in the installation holes during installation to avoid partial protrusions that may cause incomplete production of small-size boards due to protrusions of the screws. The fixing part 151 of the cell 150 is integrally arranged on the entire main frame 100 during the production of the jig; and the disassembly part 152 is produced separately, and the weight on a specific small-sized plate type can be divided into steps, and a specific first limit step 210 and a second limit step 220 can be set; and because the disassembly part 152 is the part that contacts the process and the plate type, its damage frequency is high. The disassembly part 152 is set to replace the damaged part, thereby preventing the entire main frame 100 from being scrapped and improving the life of the entire main frame 100.

[0052] In other embodiments, the fixing portion 151 is disposed outside the cell 150 to provide a fixing frame for the disassembly portion 152, and the second portion 320 of the first protrusion 300 is disposed on the fixing portion 151, and the second portion 320 is provided with a fourth fixing point 321, a fifth fixing point 322, and a sixth fixing point 323; the fourth fixing point 321, the fifth fixing point 322, and the sixth fixing point 323 are threaded inside and penetrate from the upper part of the second portion 320 to the lower part of the second portion 320, and the sixth fixing point 323 is on the opposite side of the side where the second portion 320 of the first protrusion 300 of the cell 150 is located, and the sixth fixing point 323 is disposed in the middle of the opposite side of the side where the second portion 320 of the first protrusion 300 of the cell 150 is located.

[0053] In other embodiments, the disassembly portion 152 is embedded inside the fixed portion 151, and the first part 320 of the first protrusion 300 is provided on the disassembly portion 152, the first fixing point 311 and the second fixing point 312 are threaded inside and penetrate from the upper part of the first part 310 to the lower part of the first part 310, and the third fixing point 313 is fixedly arranged in the middle on the opposite side of the side where the first part 310 of the first protrusion 300 of the unit cell 150 is located, and the third fixing point 313 is fixedly arranged in the middle, and a thread is arranged inside the third fixing point 313 and is arranged through the disassembly portion 152. During installation, the disassembly portion 152 is overlapped above the fixed portion 151, and the first fixing point 311, the second fixing point 312, and the third fixing point 313 are respectively fixed with screws through the first fixing point 321, the fifth fixing point 322, and the sixth fixing point 323, and the fixed portion 151 and the disassembly portion 152 are fixed by the relative fixation of the three fixing points.

[0054] The serial numbers of utility model embodiments are only for description and do not represent the advantages and disadvantages of the embodiments. The above are only preferred embodiments of the present invention, and do not limit the patent scope of the present invention. Any equivalent device or equivalent process transformation made by using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. An auxiliary fixture for small-sized plates, characterized in that: The invention comprises a main frame (100), wherein the main frame (100) is formed by enclosing two first outer frames (110) and two second outer frames (120); the main frame (100) is provided with a plurality of connecting plates (130); two ends of the connecting plates (130) are respectively connected to the two first outer frames (110), and the connecting plates (130) are arranged in parallel with the second outer frames (120); At least one installation cell (150) is provided between adjacent connecting plates (130) and between a connecting plate (130) and an adjacent second outer frame (120), and the installation cell (150) is provided with a plurality of limiting steps (200) for placing a small-sized PCB board; Two first protrusions (300) are arranged in the cell (150), and the first protrusions (300) are arranged at the intersection where the cell (150) is connected to the connecting plate (130), or at the intersection where the cell (150) is connected to the second outer frame (120), and the first protrusions (300) are on the same side in the cell (150), and the first protrusions (300) are composed of a first part (310) and a second part (320); The unit cell (150) is composed of a fixing portion (151) and a disassembling portion (152), wherein the fixing portion (151) is fixed on the main frame (100), and the disassembling portion (152) is disassembled from the fixing portion (151); The fixing portion (151) is arranged outside the cell (150), and the second part (320) of the first protrusion (300) is arranged on the fixing portion (151), the second part (320) is provided with a fourth fixing point (321) and a fifth fixing point (322), and a sixth fixing point (323) is further provided on the side opposite to the side where the first part (310) of the first protrusion (300) of the cell (150) is located; The disassembly portion (152) is embedded in the inner side of the fixing portion (151), and the disassembly portion (152) is provided with a first part (310) of the first protrusion (300), and the second part (320) is provided with a first fixing point (311) and a second fixing point (312). A third fixing point (313) is also provided on the side opposite to the side where the first part (310) of the first protrusion (300) of the cell (150) is located, and is fixed to the first fixing point (311), the second fixing point (312), and the third fixing point (313) respectively through the fourth fixing point (321), the fifth fixing point (322), and the sixth fixing point (323).

2. The auxiliary jig for small-sized boards according to claim 1, characterized in that: A mounting plate (140) is also connected between adjacent connecting plates (130) and between the connecting plates (130) and the adjacent second outer frames (120), and the mounting plate (140) isolates each of the cells (150).

3. The auxiliary jig for small-sized boards according to claim 1, characterized in that: A plurality of the limiting steps (200) are arranged along the inner circumference of the installation cell (150).

4. The auxiliary jig for small-sized boards according to claim 1, characterized in that: The limiting step (200) comprises a plurality of first limiting steps (210), and the plurality of first limiting steps (210) are respectively arranged on two opposite side surfaces of the installation unit cell (150).

5. The auxiliary jig for small-sized boards according to claim 4, characterized in that: The limiting step (200) comprises a plurality of second limiting steps (220), and the plurality of second limiting steps (220) are respectively arranged on two opposite side surfaces of the installation unit cell (150); the second limiting step (220) is not arranged coplanarly with the first limiting step (210).

6. The auxiliary jig for small-sized boards according to claim 5, characterized in that: The heights of the first limiting step (210) and the second limiting step (220) are smaller than the height of the inner circumference of the installation cell (150); and the horizontal heights of the first limiting step (210) and the second limiting step (220) are the same.

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