Composite fastener

Abstract

The utility model relates to a composite fastener which is used for installing a to-be-fastened piece on a fastening carrier, the composite fastener comprises an outer sleeve piece, a first end and a second end, the first end and the second end are oppositely arranged, the second end of the outer sleeve piece is provided with a first external thread section, and the second end of the outer sleeve piece penetrates through the to-be-fastened piece and is connected with the fastening carrier; the inner sleeve part and the outer sleeve part are coaxially arranged, the inner sleeve part is provided with a slender part, the end, away from the first end of the outer sleeve part, of the slender part is provided with a second external thread section, the thread turning directions of the first external thread section and the second external thread section are opposite, and the end, provided with the second external thread section, of the slender part penetrates through the outer sleeve part and is connected with the fastening carrier; one end of the pin shaft is connected to the outer sleeve piece and the inner sleeve piece in an inserted mode at the same time. Due to the fact that the thread screwing directions of the first external thread section and the second external thread section are opposite, the inner sleeve piece and the outer sleeve piece are connected into a whole through the pin shaft, the inner sleeve piece or the outer sleeve piece can be prevented from loosening, and therefore the connection reliability is improved.

Description

Technical Field

[0001] The present application relates to the technical field of fasteners, and in particular to a composite fastener. Background Art

[0002] There are many occasions that require installation in industrial applications. Some occasions (such as installations that are prone to vibration using ring mirrors) have relatively high requirements for the connection reliability of fasteners after installation.

[0003] In the prior art, conventional screws, nuts, and screw holes are all standardized right-hand thread structures (i.e., clockwise to tighten, counterclockwise to loosen), which are easily loosened under certain special environmental conditions, resulting in low connection reliability. Utility Model Content

[0004] The present application provides a composite fastener to solve the technical problem that conventional fasteners are easily affected by external force vibration and become loose, resulting in low connection reliability.

[0005] In a first aspect, an embodiment of the present application provides a composite fastener for installing a fastener on a fastening carrier, the composite fastener comprising: an outer sleeve having a first end and a second end arranged opposite to each other, the second end of the outer sleeve being provided with a first external thread segment, the second end of the outer sleeve passing through the fastener and being connected to the fastening carrier; an inner sleeve having a slender portion, the slender portion being embedded in the outer sleeve, an end of the slender portion away from the first end of the outer sleeve being provided with a second external thread segment, the first external thread segment and the second external thread segment having opposite thread rotation directions, an end of the slender portion provided with the second external thread segment passing through the outer sleeve and being connected to the fastening carrier; and a pin, one end of which is connected to both the outer sleeve and the inner sleeve.

[0006] In one possible implementation, a first positioning portion is provided at the first end of the outer sleeve, and a first pin hole is provided on the side of the first positioning portion facing away from the second end; the inner sleeve is provided with a second positioning portion connected to the slender portion, and the second positioning portion is provided with a second pin hole corresponding to the first pin hole, and one end of the pin shaft passes through the second pin hole and the first pin hole in sequence.

[0007] In a possible implementation, a plurality of first pin holes are provided, and the plurality of first pin holes are evenly distributed in a ring shape with the slender portion as the center.

[0008] In a possible implementation manner, the first pin hole has a first diameter d1, the second pin hole has a second diameter d2, and 0.9≤d1 / d2≤0.95.

[0009] In a possible implementation manner, the outer sleeve is provided with a first through hole along the axial direction of the slender portion, and the slender portion is connected to the fastening carrier after passing through the first through hole.

[0010] In a possible implementation, a third internal thread segment is disposed at the first through hole at the second end of the outer sleeve, and the third internal thread segment cooperates with the second external thread segment.

[0011] In a possible implementation, the first external thread segment has a first length L1, the third internal thread segment has a second length L2, and 0.2≤L2 / L1≤0.3.

[0012] In a possible implementation, the nominal diameter of the first external thread segment is d3, the diameter of the first through hole is d4, and 1 / 4≤d4 / d3≤1 / 3.

[0013] In a possible implementation manner, a third groove is provided at one end of the pin shaft away from the inner sleeve.

[0014] In a possible implementation, the fastener is provided with a second through hole for the second end of the outer sleeve to pass through, the fastening carrier is provided with a first internal thread segment matching with the first external thread segment, and the fastening carrier is provided with a second internal thread segment matching with the second external thread segment.

[0015] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:

[0016] A composite fastener provided in an embodiment of the present application, during installation, firstly, an outer sleeve is passed through the fastener to be fastened and is screwed onto a fastening carrier so that the outer sleeve is fixedly connected to the fastening carrier; then, an inner sleeve is passed through the outer sleeve and is screwed onto the fastening carrier so that the inner sleeve is fixedly connected to the fastening carrier, and a pin is simultaneously inserted and connected to the outer sleeve and the inner sleeve so that a hard connection is formed between the outer sleeve and the inner sleeve. Since the threads of the first external thread section and the second external thread section have opposite rotation directions, taking the example that the thread of the first external thread section is set as a right-hand thread and the thread of the second external thread section is set as a left-hand thread, if the outer sleeve is vibrated by external force and rotates counterclockwise or tends to rotate counterclockwise, the inner sleeve is tightened counterclockwise under the action of friction, and since the pin shaft connects the inner sleeve and the outer sleeve as a whole, the force between the inner sleeve and the outer sleeve can prevent the outer sleeve from loosening counterclockwise; similarly, if the inner sleeve is vibrated by external force and rotates clockwise or tends to rotate clockwise, then the outer sleeve is tightened clockwise under the action of friction, and since the pin shaft connects the inner sleeve and the outer sleeve as a whole, the force between the inner sleeve and the outer sleeve can prevent the inner sleeve from loosening clockwise, thereby improving the connection reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0018] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0019] One or more embodiments are exemplarily described by pictures in the corresponding drawings, and these exemplified descriptions do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings represent similar elements, and unless otherwise stated, the figures in the drawings do not constitute proportional limitations.

[0020] Figure 1 A schematic diagram of the structure of a composite fastener provided in an embodiment of the present application;

[0021] Figure 2 for Figure 1 An exploded schematic diagram of the structure of the composite fastener is shown;

[0022] Figure 3 for Figure 1 A schematic diagram of the installation state of the composite fastener shown;

[0023] Figure 4 for Figure 1 A perspective view of an outer sleeve of a composite fastener is shown;

[0024] Figure 5 for Figure 1 A perspective view of an inner set of composite fasteners is shown;

[0025] Figure 6 for Figure 1 A cross-sectional view of the composite fastener shown;

[0026] Figure 7 for Figure 1 A perspective view of a pin of a composite fastener is shown.

[0027] Description of reference numerals:

[0028] 1. Composite fastener; 11. Outer set; 111. First end; 112. Second end; 112a. First external thread segment; 112b. Third internal thread segment; 113. First positioning portion; 113a. First pin hole; 114. First through hole; 113b. First groove; 12. Inner set; 121. Elongated portion; 121a. Second external thread segment; 122. Second positioning portion; 122a. Second pin hole; 122b. Second groove; 13. Pin shaft; 131. Third groove;

[0029] 2. The fastener to be fastened; 21. The second through hole; 3. The fastening carrier; 31. The first internal thread segment; 32. The second internal thread segment. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0031] The disclosure below provides many different embodiments or examples to realize the different structures of the present application. In order to simplify the disclosure of the present application, the parts and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present application. In addition, the present application can repeat reference numbers and / or letters in different examples. This repetition is for the purpose of simplification and clarity, and does not itself indicate the relationship between the various embodiments and / or settings discussed.

[0032] For ease of description, spatial relative terms may be used herein to describe the relative positional relationship or movement of one element or feature relative to another element or feature as shown in the figure, such as "inside", "outside", "inner side", "outer side", "below", "below", "above", "above", "front", "back", etc. Such spatial relative terms are intended to include different orientations of the device in use or operation in addition to the orientation depicted in the figure. For example, if the device in the figure undergoes a position flip or a posture change or a motion state change, then these directional indications also change accordingly, for example: an element described as "below other elements or features" or "below other elements or features" will subsequently be oriented as "above other elements or features" or "above other elements or features". Therefore, the example term "below..." may include both upper and lower orientations. The device may be otherwise oriented (rotated 90 degrees or in other directions) and the spatial relative descriptors used herein are interpreted accordingly.

[0033] In order to solve the technical problem that existing conventional fasteners are easily affected by external force vibration and become loose, resulting in low connection reliability, the present application provides a composite fastener that can prevent the inner set or the outer set from loosening and improve the connection reliability.

[0034] Figure 1A composite fastener 1 provided in an embodiment of the present application is used to install a fastener 2 to be fastened on a fastening carrier 3. The composite fastener 1 includes an outer set 11, an inner set 12 and a pin 13. The outer set 11 has a first end 111 and a second end 112 arranged opposite to each other. The second end 112 of the outer set 11 is provided with a first external thread section 112a. The second end 112 of the outer set 11 passes through the fastener 2 to be fastened and is connected to the fastening carrier 3. The inner set 12 can be coaxially arranged with the outer set 11. The inner sleeve 12 is provided with a slender portion 121, which is embedded in the outer sleeve 11, and an end of the slender portion 121 away from the first end 111 of the outer sleeve 11 is provided with a second external thread segment 121a, and the thread rotation directions of the first external thread segment 112a and the second external thread segment 121a are opposite, and one end of the slender portion 121 provided with the second external thread segment 121a passes through the outer sleeve 11 and is connected to the fastening carrier 3; one end of the pin shaft 13 is connected to both the outer sleeve 11 and the inner sleeve 12.

[0035] The fastener 2 can be a flange of a motor, a large plate of an equipment, etc., and the fastening carrier 3 can be a wall, a ground, a mounting plate, etc. For example, if the air conditioner needs to be installed on a wall, then the air conditioner is the fastener 2 in the embodiment of the present application, and the wall is the fastening carrier 3 in the embodiment of the present application. It should be noted that the thread of the first external thread segment 112a can be set as a right-handed thread, and the thread of the second external thread segment 121a is set as a left-handed thread; or, the thread of the first external thread segment 112a can be set as a left-handed thread, and the thread of the second external thread segment 121a is set as a right-handed thread. It can be understood that if Figure 2 As shown, during installation, the outer set 11 is first passed through the fastener 2 and screwed on the fastening carrier 3, so that the outer set 11 is fixedly connected to the fastening carrier 3; then the inner set 12 is passed through the outer set 11 and screwed on the fastening carrier 3, so that the inner set 12 is fixedly connected to the fastening carrier 3, and the pin 13 is simultaneously connected to the outer set 11 and the inner set 12, so that a hard connection is formed between the outer set 11 and the inner set 12, as shown in FIG. Figure 3As shown. Since the first external thread segment 112a and the second external thread segment 121a have opposite thread directions, the thread of the first external thread segment 112a is set as a right-hand thread, and the thread of the second external thread segment 121a is set as a left-hand thread. If the outer sleeve 11 rotates counterclockwise or tends to rotate counterclockwise due to external force vibration, the inner sleeve 12 is tightened counterclockwise under the action of friction. Since the pin 13 connects the inner sleeve 12 and the outer sleeve 11 as a whole, the force between the inner sleeve 12 and the outer sleeve 11 can prevent the outer sleeve 11 from loosening counterclockwise. Similarly, if the inner sleeve 12 rotates clockwise or tends to rotate clockwise due to external force vibration, the outer sleeve 11 is tightened clockwise under the action of friction. Since the pin 13 connects the inner sleeve 12 and the outer sleeve 11 as a whole, the force between the inner sleeve 12 and the outer sleeve 11 can prevent the inner sleeve 12 from loosening clockwise, thereby improving the connection reliability.

[0036] In some embodiments, Figure 4 and Figure 5 As shown, the first end 111 of the outer sleeve 11 is provided with a first positioning portion 113, and the first positioning portion 113 is provided with a first pin hole 113a along the axial direction of the pin shaft 13 on the side away from the second end 112; the inner sleeve 12 has a second positioning portion 122 connected to the elongated portion 121, and the elongated portion 121 and the second positioning portion 122 are integrally provided, and the second positioning portion 122 is provided with a second pin hole 122a corresponding to the first pin hole 113a along the axial direction of the pin shaft 13, and one end of the pin shaft 13 passes through the second pin hole 122a and the first pin hole 113a in sequence. One end of the pin shaft 13 is inserted into the first pin hole 113a and the second pin hole 122a in sequence, so that the outer sleeve 11 and the inner sleeve 12 form a hard connection, and the pin shaft 13 can provide a fastening force to prevent the outer sleeve 11 or the inner sleeve 12 from being loosened relative to the fastening carrier 3 due to external force vibration, and further improve the connection reliability.

[0037] The first positioning portion 113 is provided with a first groove 113b on the side away from the second end 112, and the first groove 113b is preferably set to a regular hexagon so that it can be tightened with a common tool in the industry. The second positioning portion 122 is provided with a second groove 122b on the side away from the elongated portion 121, and the second groove 122b is preferably set to a regular hexagon so that it can be tightened with a common tool in the industry. After the inner kit 12 is connected to the fastening carrier 3, the side of the second positioning portion 122 facing the fastening carrier 3 is tightly fitted with the first groove 113b.

[0038] In some embodiments, Figure 4As shown, a plurality of first pin holes 113a are provided, and the plurality of first pin holes 113a are distributed in a ring shape with the elongated portion 121 of the inner sleeve 12 as the center. Specifically, the plurality of first pin holes 113a are evenly distributed in a ring shape with the elongated portion 121 of the inner sleeve 12 as the center. The plurality of first pin holes 113a are provided so that after the inner sleeve 12 is rotated and tightened, the second pin hole 122a is aligned with one of the first pin holes 113a, and the installation of the pin shaft 13 is more convenient.

[0039] like Figure 6 As shown, the first pin hole 113a has a first diameter d1, and the second pin hole 122a has a second diameter d2, 0.9≤d1 / d2≤0.95. Since the inner sleeve 12 needs to be rotated to align the second pin hole 122a with one of the first pin holes 113a, the second pin hole 122a is set to be slightly smaller than the first pin hole 113a, so that the pin shaft 13 can be inserted into the first pin hole 113a and the second pin hole 122a in sequence.

[0040] In some embodiments, Figure 6 As shown, the outer sleeve 11 is provided with a first through hole 114 along the axial direction of the elongated portion 121, and the elongated portion 121 is connected to the fastening carrier 3 after passing through the first through hole 114. It should be noted that the cross section of the first through hole 114 can be set to a circular shape, a square shape, etc., which is not limited here. This embodiment shows that the cross section of the first through hole 114 is set to a circular shape, and the elongated portion 121 of the inner sleeve 12 is connected to the fastening carrier 3 after passing through the first through hole 114, and the first through hole 114 plays a role in positioning and guiding.

[0041] In some embodiments, the second end 112 of the outer sleeve 11 is provided with a third internal thread segment 112b at the first through hole 114, and the third internal thread segment 112b cooperates with the second external thread segment 121a. In some embodiments, the pin shaft 13 may not be installed, and only the thread cooperation between the third internal thread segment 112b and the second external thread segment 121a is used to achieve the purpose of preventing loosening by utilizing the friction between the inner sleeve 12 and the outer sleeve 11. Specifically, after the fastener 2 is installed on the fastening carrier 3 by the outer sleeve 11 and the inner sleeve 12 (without the pin shaft 13), if the outer sleeve 11 has a tendency to rotate counterclockwise due to external force vibration, the friction between the inner sleeve 12 and the outer sleeve 11 will apply a counterclockwise rotation force to the inner sleeve 12, thereby strengthening the locking of the inner sleeve 12, and the locking force of the inner sleeve 12 will prevent the outer sleeve 11 from loosening counterclockwise. Similarly, if the inner sleeve 12 is vibrated by external force and has a tendency to rotate clockwise, the friction force exerts a force on the outer sleeve 11 to rotate clockwise, thereby strengthening the locking of the outer sleeve 11. The locking force of the outer sleeve 11 will prevent the inner sleeve 12 from loosening clockwise, thereby achieving the purpose of preventing loosening. Therefore, by providing the third internal thread section 112b, the connection stability between the inner sleeve 12 and the outer sleeve 11 can be improved, and the anti-loosening performance of the composite fastener 1 can be further improved.

[0042] The length of the third internal thread segment 112b should not be too long, otherwise it will affect the normal connection between the inner sleeve 12 and the fastening carrier 3; the length of the third internal thread segment 112b should not be too short, otherwise the connection strength between the inner sleeve 12 and the outer sleeve 11 will be weak. Therefore, the first external thread segment 112a has a first length L1, and the third internal thread segment 112b has a second length L2, 0.2≤L2 / L1≤0.3, which can ensure sufficient connection strength between the inner sleeve 12 and the outer sleeve 11, and will not affect the normal connection between the inner sleeve 12 and the fastening carrier 3.

[0043] If the ratio between the nominal diameters of the first through hole 114 and the first external thread segment 112a is too large, the wall thickness of the second end 112 of the outer sleeve 11 will be too thin. Therefore, the nominal diameter of the first external thread segment 112a is d3, the diameter of the first through hole 114 is d4, and 1 / 4≤d4 / d3≤1 / 3, so that the second end 112 of the outer sleeve 11 has a suitable wall thickness, thereby ensuring that the outer sleeve 11 has sufficient structural strength.

[0044] In some embodiments, Figure 7As shown, a third groove 131 is provided on the circumferential side of the end of the pin shaft 13 away from the inner sleeve 12. The number of the third grooves 131 is not limited, and may include at least two third grooves 131 (as shown in the figure) or at least three third grooves 131 (not shown). The third grooves 131 may be the same or different. By providing the third grooves 131, it is convenient to clamp with tools, and it is also convenient to adjust the clamping force required for installing the pin shaft 13, so that the pin shaft 13 is easier to disassemble and assemble. The shape of the third groove 131 can be set to a square (not shown), a half-moon shape (as shown in the figure), etc., to facilitate manufacturing and processing.

[0045] In some embodiments, Figure 3 As shown, the fastener 2 is provided with a second through hole 21 for the second end 112 of the outer sleeve 11 to pass through, the fastening carrier 3 is provided with a first internal thread section 31 matched with the first external thread section 112a, and the fastening carrier 3 is provided with a second internal thread section 32 matched with the second external thread section 121a. During installation, firstly, the outer sleeve 11 is passed through the second through hole 21 of the fastener 2 and screwed on the fastening carrier 3, so that the outer sleeve 11 and the fastening carrier 3 are fixedly connected; then, the elongated portion 121 of the inner sleeve 12 is passed through the first through hole 114 of the outer sleeve 11 and screwed on the fastening carrier 3, so that the inner sleeve 12 and the fastening carrier 3 are fixedly connected, and the pin 13 is simultaneously plugged and connected to the outer sleeve 11 and the inner sleeve 12, so that a hard connection is formed between the outer sleeve 11 and the inner sleeve 12.

[0046] It should be emphasized that the composite fastener 1 provided in the embodiment of the present application has no specific size limitation and no specific shape limitation. Those skilled in the art can enlarge or reduce the size according to the specific needs of use, or can enlarge or reduce one or several parts according to the proportion; and can also make appropriate changes to the shape of one or several parts under the premise of complying with the principle.

[0047] It should be understood that the terms used herein are only for the purpose of describing specific example embodiments and are not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms "one", "an" and "said" as used herein may also be meant to include plural forms. The terms "include", "comprise", "contain", and "have" are inclusive, and therefore specify the existence of stated features, steps, operations, elements and / or parts, but do not exclude the existence or addition of one or more other features, steps, operations, elements, parts, and / or combinations thereof. The method steps, processes, and operations described herein are not interpreted as necessarily requiring them to be performed in the specific order described or illustrated, unless the execution order is clearly indicated. It should also be understood that additional or alternative steps may be used.

[0048] Although the terms first, second, third, etc. can be used in the text to describe multiple elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms can only be used to distinguish an element, component, region, layer or section from another region, layer or section. Unless the context clearly indicates, terms such as "first", "second" and other numerical terms do not imply order or sequence when used in the text. Therefore, the first element, component, region, layer or section discussed below can be referred to as the second element, component, region, layer or section without departing from the teaching of the example embodiments.

[0049] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. A composite fastener, used for mounting a fastener (2) on a fastening carrier (3), characterized in that: The composite fastener comprises: An outer sleeve (11) having a first end (111) and a second end (112) arranged opposite to each other, the second end (112) of the outer sleeve (11) being provided with a first external thread section (112a), the second end (112) of the outer sleeve (11) penetrating the fastener (2) and being connected to the fastening carrier (3); The inner sleeve (12) is provided with a slender portion (121), the slender portion (121) is embedded in the outer sleeve (11), the end of the slender portion (121) away from the first end (111) of the outer sleeve (11) is provided with a second external thread segment (121a), the first external thread segment (112a) and the second external thread segment (121a) have opposite thread rotation directions, and the end of the slender portion (121) provided with the second external thread segment (121a) passes through the outer sleeve (11) and is connected to the fastening carrier (3); and A pin shaft (13), one end of which is connected to both the outer sleeve (11) and the inner sleeve (12).

2. The composite fastener according to claim 1, characterized in that: The first end (111) of the outer sleeve (11) is provided with a first positioning portion (113), and a first pin hole (113a) is provided on a side of the first positioning portion (113) away from the second end (112); The inner sleeve (12) is provided with a second positioning portion (122) connected to the slender portion (121), and the second positioning portion (122) is provided with a second pin hole (122a) corresponding to the first pin hole (113a), and one end of the pin shaft (13) passes through the second pin hole (122a) and the first pin hole (113a) in sequence.

3. The composite fastener according to claim 2, characterized in that: A plurality of the first pin holes (113a) are provided, and the plurality of the first pin holes (113a) are distributed in a ring shape with the elongated portion (121) as the center.

4. The composite fastener according to claim 2, characterized in that: The first pin hole (113a) has a first diameter d1, and the second pin hole (122a) has a second diameter d2, and 0.9≤d1 / d2≤0.

95.

5. The composite fastener according to claim 1, characterized in that: The outer sleeve (11) is provided with a first through hole (114) along the axial direction of the slender portion (121), and the slender portion (121) is connected to the fastening carrier (3) after passing through the first through hole (114).

6. The composite fastener according to claim 5, characterized in that: The second end (112) of the outer sleeve (11) is provided with a third internal thread section (112b) at the first through hole (114), and the third internal thread section (112b) cooperates with the second external thread section (121a).

7. The composite fastener according to claim 6, characterized in that: The first external thread segment (112a) has a first length L1, and the third internal thread segment (112b) has a second length L2, and 0.2≤L2 / L1≤0.

3.

8. The composite fastener according to claim 5, characterized in that: The nominal diameter of the first external thread section (112a) is d3, the diameter of the first through hole (114) is d4, and 1 / 4≤d4 / d3≤1 / 3.

9. The composite fastener according to claim 1, characterized in that: A third groove (131) is provided at one end of the pin shaft (13) away from the inner sleeve (12).

10. The composite fastener according to any one of claims 1 to 9, characterized in that: The fastener (2) is provided with a second through hole (21) for the second end (112) of the outer sleeve (11) to pass through, the fastening carrier (3) is provided with a first internal thread segment (31) cooperating with the first external thread segment (112a), and the fastening carrier (3) is provided with a second internal thread segment (32) cooperating with the second external thread segment (121a).

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