Pitch memory device for threaded rebar and method for adjusting the pitch of threaded rebar.
The pitch memory device facilitates efficient and space-saving production of precast beams by simplifying the pitch alignment process, addressing the challenges of complex procedures and space requirements in existing methods.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- ISHIKAWA PII SHII IND
- Filing Date
- 2024-12-09
- Publication Date
- 2026-06-19
AI Technical Summary
Existing methods for manufacturing precast beams using threaded reinforcing bars require significant space and involve complex procedures for pitch matching, making it difficult for small factories to produce multiple beams simultaneously and complicating the alignment of pitches between pre-assembled and later-assembled beams.
A pitch memory device comprising a support structure, slide guide, carriage, and threaded member with male threaded portions that allows for easy alignment and storage of the pitch of threaded reinforcing bars, enabling separate manufacturing of precast members and simple pitch matching at the construction site.
Enables efficient, space-saving production of precast beams with simplified pitch alignment procedures, allowing for accurate and intuitive matching of pitches between pre-assembled and later-assembled beams using the pitch memory device.
Smart Images
Figure 2026100145000001_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a pitch memory device for screw bars intended to be used as main bars of precast members arranged sandwiching a joint part at a construction site for pitch matching of screw bars with each other, and a method for pitch matching of screw bars of a precast member in a front group and a precast member in a rear group using this pitch memory device.
Background Art
[0002] A precast beam (precast member) is manufactured by embedding a steel bar cage in concrete at a factory or the like and transported to a construction site. The steel bar cage has a plurality of main bars extending in the longitudinal direction. The main bars protrude from the end face of the precast beam (the end face of the concrete). The protruding length of this main bar is managed to a predetermined length within the allowable error range. The precast beams are arranged in a straight line so as to face each other with a joint part sandwiched therebetween at the construction site. At the joint part, after connecting the ends of the main bars protruding from adjacent precast beams, concrete is placed at the joint part, whereby the precast beams are connected to each other and a continuous precast beam is constructed.
[0003] When using screw bars (bars having screw threads on the outer periphery) as main bars, the ends of the screw bars are connected with a coupler nut. Hereinafter, this connecting process will be briefly described taking as an example the case where the protruding lengths of the screw bars from adjacent precast beams are equal in design. In a state where adjacent precast beams are installed as designed, the screw bars are arranged in a straight line and their end faces face each other with a slight gap at the center of the joint part. A coupler nut is pre-screwed onto the screw bar of one precast beam, and by turning this coupler nut, each half of the coupler nut is screwed onto the end of the screw bar of the adjacent precast beam. In this way, the screw bars are connected to each other via the coupler nut.
[0004] At a construction site, if the pitch of the threaded reinforcing bars of adjacent precast beams does not match, they cannot be connected with coupler nuts. Therefore, as disclosed as prior art in Figure 11 of Patent Document 1, when manufacturing precast beams in a factory, multiple formworks are arranged on a bed so that the precast beams are positioned according to the design drawings, and the threaded reinforcing bars of the reinforcing cages housed in each formwork are made to protrude horizontally from the formwork. Next, a cylindrical nut (pitch matching jig) is used to move at least one of the threaded reinforcing bars protruding from adjacent formworks in the axial direction to match the pitch of the ends of the threaded reinforcing bars, and they are connected with a cylindrical nut in the same way as coupler nuts at a construction site.
[0005] As described above, the precast beams are manufactured by pouring concrete into multiple formwork while they are connected by cylindrical nuts. After the precast beams are completed, the cylindrical nuts are removed from the threaded reinforcing bars, and the precast beams are transported individually to the construction site. At a construction site, the threaded reinforcing bars of precast beams adjacent to each other across the joint are pre-aligned in pitch using cylindrical nuts as described above, so they can be connected using coupler nuts. However, the above method requires a long space in the factory to manufacture multiple precast beams simultaneously, making it impossible to manufacture in small factories.
[0006] Patent Document 1 proposes a manufacturing method that does not require space to manufacture multiple precast beams simultaneously in a factory, but only space to manufacture precast beams individually, and a pitch memory device for threaded reinforcing bars used in this manufacturing method. The pitch memory device proposed in Patent Document 1 comprises a cylindrical nut and an angle memory ring rotatably externally fitted onto the cylindrical nut. A fixing screw is screwed into the angle memory ring. The cylindrical nut is screwed onto the threaded reinforcing bars of the pre-assembled precast beam, and when the axial center of the cylindrical nut reaches the axial center position (design position) of the coupler nut to be placed at the construction site, the angle of the angle memory ring is adjusted so that the fixing screw is at the top, and the fixing screw is tightened to fix the angle memory ring to the cylindrical nut. This effectively stores the pitch of the threaded reinforcing bars of the pre-assembled precast beam.
[0007] Next, formwork for the later-assembled precast beams is installed on the bed where the first-assembled precast beams were manufactured. The reinforcing cage is placed in this formwork, and the threaded reinforcing bars are made to protrude horizontally from the formwork. The center of the cylindrical nut is aligned with the axial center position of the coupler nut to be placed at the construction site, and the fixing screw of the angle memory ring is positioned at the top. This reproduces the same pitch as the female thread of the coupler nut to be placed at the construction site. The position of the later-assembled threaded reinforcing bars is adjusted so that they screw into this cylindrical nut. In this way, the pitch of the threaded reinforcing bars of the first-assembled and later-assembled precast beams can be matched. After that, concrete is poured into the formwork to manufacture the later-assembled precast beams. [Prior art documents] [Patent Documents]
[0008] [Patent Document 1] Japanese Patent Publication No. 2003-247300 [Overview of the Initiative] [Problems that the invention aims to solve]
[0009] The manufacturing method using a pitch memory device proposed in Patent Document 1 contributes to space saving in the manufacture of precast beams, but the operation of the angle memory ring is complicated. In addition, the process of matching the pitch of the pitch memory device with the threaded reinforcing bars of the precast beams assembled later requires a complicated procedure, and it is difficult for workers to learn this procedure. [Means for solving the problem]
[0010] The present invention was made to solve the above problems, and is a pitch memory device for storing the pitch of threaded reinforcing bars which are the main reinforcement of a pre-assembled precast member or reinforcing cage, The device comprises a support structure, a slide guide provided on the support structure, a carriage slidably supported on the slide guide in the axial direction of the threaded reinforcing bar, a first fixing means for fixing the carriage to the slide guide so as not to slide, a threaded member extending in the axial direction of the threaded reinforcing bar having a rotating portion rotatably supported on the carriage, and first and second male threaded portions formed on both axial sides of the rotating portion and protruding from the carriage, wherein the first and second male threaded portions have the same diameter and pitch as the threaded reinforcing bar and their pitches match each other across the rotating portion, and a second fixing means for fixing the threaded member to the carriage so as not to rotate, The carriage can be slid to join the end face of the first male threaded portion to the tip face of the threaded reinforcing bar, and by rotating the threaded member in this joined state, the pitch of the first male threaded portion can be matched to the pitch of the threaded reinforcing bar, and the first fixing means can be used to fix the carriage to the slide guide, and the second fixing means can be used to fix the threaded member to the carriage, thereby enabling the pitch of the threaded reinforcing bar to be stored.
[0011] According to the above configuration, with the support structure positioned in a predetermined location, the pitch of the threaded reinforcing bars can be easily stored by matching the pitch of the first male threaded portion of the threaded member to the pitch of the threaded reinforcing bars in the pre-assembled precast beam or reinforcing cage. Then, by positioning the support structure with the stored pitch of the pre-assembled threaded reinforcing bars in a predetermined location relative to the later-assembled reinforcing cage, and matching the pitch of the threaded reinforcing bars in the later-assembled reinforcing cage to the pitch of the second male threaded portion of the pitch storage device, the pitch of the later-assembled threaded reinforcing bars can be matched to the pitch of the pre-assembled threaded reinforcing bars. In this way, even though the pre-assembled and later-assembled precast members are manufactured separately to save space, the pitch matching of the threaded reinforcing bars between them can be achieved with a simple procedure.
[0012] In one embodiment, the protruding lengths of the first and second male screw portions from the carriage are equal. In one embodiment, the first fixing means includes a first fixing screw that is screwed into the carriage and whose tip contacts the slide guide, and the second fixing means includes a second fixing screw that is screwed into the carriage and whose tip contacts the rotating portion of the screw member.
[0013] Another aspect of the present invention is a method for aligning the pitch of threaded reinforcing bars of pre-assembled and later-assembled pre-cast members that face each other across a joint at a construction site, using a threaded reinforcing bar pitch memory device, The axial center position of the coupler nut with respect to the precast member of the first assembly is defined as the first coupler nut center position, and the axial center position of the coupler nut with respect to the precast member of the second assembly is defined as the second coupler nut center position. A pitch storage step involves positioning the support structure of the pitch storage device at a first reference position where its specific position is separated from the center position of the first coupler nut by a distance equivalent to half the axial length of the screw member relative to the pre-assembled precast member or reinforcing cage, and storing the pitch of the screw reinforcing bars of the pre-assembled precast member or reinforcing cage by the sliding of the carriage and the rotation of the screw member. Next, the support structure of the pitch storage device is positioned at a second reference position where the specific position is a distance from the center position of the second coupler nut to the reinforcing cage for the later assembled precast member, corresponding to half the axial length of the screw member, and the screw reinforcing bars of the reinforcing cage for the later assembled precast member are positioned in a pitch adjustment step to match the pitch of the second male screw portion of the screw member. It is characterized by having the following features.
[0014] According to the method described above, the reference position for positioning the support structure of the pitch memory device in the pitch memory process and the pitch matching process can be set using only the information of the axial center position of the coupler nut at the joint and the length information of the screw member of the pitch memory device. Furthermore, in the process of matching the pitch of the later-assembled threaded reinforcing bars, the second male thread portion of the screw member of the pitch memory device can accurately reproduce the axial position and pitch of the previously assembled threaded reinforcing bars. As a result, the operator can intuitively recognize the axial position and pitch of the previously assembled threaded reinforcing bars and perform the pitch matching of the later-assembled threaded reinforcing bars with an extremely simple procedure.
[0015] Preferably, the specific position of the support structure is at the axial center of the threaded reinforcing bar within the support structure.
[0016] Preferably, a semi-cylindrical gauge having female threads with the same pitch as the threaded reinforcing bar and the first and second male threads is prepared, and in the pitch memory step, the pitch matching between the threaded reinforcing bar of the pre-assembled precast member or reinforcing cage and the first male thread of the threaded member is confirmed by placing the gauge over the threaded reinforcing bar and the first male thread, and in the pitch matching step, the pitch matching between the threaded reinforcing bar of the reinforcing cage for the later-assembled precast member and the second male thread of the threaded member is confirmed by placing the gauge over the threaded reinforcing bar and the second male thread. This method allows for smooth alignment verification using a semi-cylindrical gauge.
[0017] Preferably, a positioning mark is displayed at a specific position on the support structure, a first reference mark is displayed at a first reference position at one end of the bed for precasting, and a second reference mark is displayed at a second reference position at the other end of the bed. In the pitch storage step, the support structure of the pitch storage device is positioned by aligning the positioning mark with the first reference mark, and in the pitch adjustment step, the support structure of the pitch storage device is positioned by aligning the positioning mark with the second reference mark. This method allows for easy and highly accurate positioning of the support structure for the pitch memory device.
[0018] In one embodiment, the axial center of the coupler is located in the center of the joint, and the distance from the pre-assembled precast member to the center position of the first coupler nut is equal to the distance from the post-assembled precast member to the center position of the second coupler nut. [Effects of the Invention]
[0019] As described above, by using the threaded reinforcing bar pitch memory device of the present invention, precast members can be manufactured individually, and the pitch of the later-assembled threaded reinforcing bars can be matched to the pitch of the earlier-assembled threaded reinforcing bars with a simple procedure. [Brief explanation of the drawing]
[0020] [Figure 1] (A) is a side view showing a precast beam manufactured by the method according to an embodiment of the present invention, arranged with a joint portion sandwiched at a construction site, and (B) is an enlarged cross-sectional view showing a state where screw reinforcing bars of the precast beam are connected by a coupler nut. [Figure 2] (A) is a side view showing a step of storing the pitch of the screw reinforcing bars of the precast beam in advance in a pitch storage device according to an embodiment of the present invention, and (B) is a plan view of the main part. [Figure 3] (A) is a side view showing a step of reproducing the pitch of the screw reinforcing bars of the precast beam in advance stored in the pitch storage device with respect to the reinforcing bar cage before precasting the precast beam assembled later, and (B) is a plan view of the main part. [Figure 4] It is a plan view of the same pitch storage device. [Figure 5] It is a side view of the pitch storage device in FIG. 4 as viewed from the direction of arrow V. [Figure 6] It is a side cross-sectional view of the same pitch storage device. [Figure 7] It is a cross-sectional view taken along the line VII-VII of FIG. 5. [Figure 8] It is a view of the pitch storage device in FIG. as viewed from the direction of arrow VIII. [Figure 9] The initial stage in the pitch storage step (the step of storing the pitch of the screw reinforcing bars of the precast beam in advance) shown in FIG. 2 is enlarged and shown, where (A) is a plan view and (B) is a side view. [Figure 10] In the next stage of the same step, a state where the carriage of the pitch storage device is slid in the axial direction and the screw member is applied to the screw reinforcing bar is shown, where (A) is a plan view and (B) is a side view. [Figure 11] In the further next stage of the same step, a state where the screw member of the pitch storage device is rotated to match the pitch of the screw member with the pitch of the screw reinforcing bar is shown, where (A) is a plan view, (B) is a side view, and (C) is a perspective view. [Figure 12]Figure 3 shows the initial stage of the pitch adjustment process (a process of adjusting the pitch of threaded reinforcing bars in the reinforcing cage for a post-assembled precast beam using a pitch memory device), where (A) is a plan view and (B) is a side view. [Figure 13] The images show the state after pitch alignment has been completed in the same process, with (A) being a top view and (B) being a side view. [Modes for carrying out the invention]
[0021] The following describes one embodiment of the present invention with reference to the drawings. First, with reference to Figure 1, the joint structure at the construction site will be briefly explained. Precast beams 1A and 1B (precast members) are aligned in a straight line and face each other with a joint 6 in between. The precast beams 1A and 1B are constructed by embedding a reinforcing cage 2 in concrete 3. In this embodiment, the reinforcing cage 2 has four threaded reinforcing bars each in the lower row 4 and four threaded reinforcing bars each in the upper row 5 as main reinforcement, and is precast except for the upper part of the reinforcing cage 2. Therefore, the upper threaded reinforcing bars 5 are exposed to the outside, and only the lower threaded reinforcing bars 4 are embedded in concrete 3. The threaded reinforcing bars 4 and 5 of the precast beams 1A and 1B are connected to each other by coupler nuts 7. Once all the threaded reinforcing bars 4 and 5 of the precast beams 1A and 1B are connected, concrete is poured into the joint 6 to construct a continuous precast beam. In this embodiment, concrete is poured into the top of the reinforcing cages 2 of the precast beams 1A and 1B at the same time as the joint 6.
[0022] In this embodiment, the design protrusion length of the threaded reinforcing bars 4 and 5 of precast beam 1A from the end face of precast beam 1A (the end face of concrete 3) is the same as the protrusion length of the threaded reinforcing bars 4 and 5 of precast beam 1B. Therefore, in design, the threaded reinforcing bars 4 and 5 that form the same axis in precast beams 1A and 1B are spaced apart at a predetermined interval, for example, 20 mm apart, and are set back at an equidistant distance from the center 6c of the joint 6. However, in reality, the protrusion length of the threaded reinforcing bars 4 and 5 has a tolerance of, for example, about 10 mm.
[0023] In the design, the axial center 7c of the coupler nut 7 coincides with the center of the spacing between threaded reinforcing bars 4 and the center of the spacing between threaded reinforcing bars 5. In this embodiment, the axial center 7c of the coupler nut 7 coincides with the center 6c of the joint portion 6. The distance from the end faces of the precast beams 1A and 1B to the axial center 7c of the coupler nut 7 is indicated by the symbol M in Figure 1(A).
[0024] If the protruding lengths of the threaded reinforcing bars 4 and 5 of the precast beam 1A differ from the protruding length of the precast beam 1A, the axial center 7c of the coupler nut 7 will be further away from the center 6c of the joint 6. In this case, the distance from the end faces of the precast beams 1A and 1B to the axial center 7c of the coupler nut 7 will also differ.
[0025] <Outline of the manufacturing method of precast beams> The schematic of the manufacturing method for precast beams of the present invention will be explained with reference to Figures 2 and 3. Figure 2 shows the state after the precasting of the first assembled precast beam 1A is completed and the formwork has been removed. The first assembled precast beam 1A is installed on the bed 100 in the position it was in when the precasting was completed. The right ends of the threaded reinforcing bars 4 and 5 of the first assembled precast beam 1A are to be connected to the threaded reinforcing bars 4 and 5 of the later assembled precast beam 1B.
[0026] A pitch storage device 10 according to one embodiment of the present invention is installed at a predetermined position on the right end of the bed 100. As will be described later, this pitch storage device 10 is installed at a predetermined distance from the end face 1x of the pre-assembled precast beam 1A and stores the pitch of the lower threaded reinforcing bars 4.
[0027] Next, the pre-assembled precast beam 1A is removed from the bed 100, and as shown in Figure 3, formwork 101 is installed in the same position, along with a reinforcing cage 2 for the later-assembled precast beam 1B inside the formwork 101. The lower threaded reinforcing bars 4 of the reinforcing cage 2 penetrate the formwork 101 and protrude horizontally. The left ends of these threaded reinforcing bars 4 and 5 are intended to be connected to the threaded reinforcing bars 4 and 5 of the pre-assembled precast beam 1A.
[0028] As described later, a pitch memory device 10, which stores the pitch of the threaded reinforcing bars 4 of the pre-assembled precast beam 1A, is installed at a predetermined position on the left end of the bed 100 (a predetermined distance from the inner surface 101x of the formwork 101). Then, the threaded reinforcing bars 10 protruding from the formwork 101 are adjusted in the axial direction to match the pitch of the threaded reinforcing bars 4 of the pre-assembled precast beam 1A stored in the pitch memory device 10.
[0029] Once the pitch alignment of the lower threaded reinforcing bars 4 in the later-assembled reinforcing cage 2 is complete, the lock nuts 102 screwed onto both ends of the threaded reinforcing bars 4 are tightened to the formwork 101 to fix the threaded reinforcing bars 4 to the formwork 101. After that, concrete is poured into the formwork 101 to manufacture the later-assembled precast beam 1B.
[0030] As described above, the pre-assembled precast beam 1A and the pre-assembled precast beam 1B are manufactured individually on a common bed 100, eliminating the need to manufacture these precast beams 1A and 1B side by side, thus requiring only a small space. Furthermore, the pitch memory device 10 allows the threaded reinforcing bars 4 of the precast beams 1A and 1B to be aligned in pitch, enabling them to be securely connected at the construction site using coupler nuts 7, as shown in Figure 1. In this embodiment, as shown in Figure 1, the upper threaded reinforcing bars 5 of the precast beams 1A and 1B are not fixed in concrete 3, so they can be adjusted axially at the construction site to match the pitch and connected with coupler nuts 7.
[0031] <Structure of pitch memory device> Next, the detailed structure of the pitch memory device 10 will be explained with reference to Figures 4 to 8. As shown in Figures 2 and 3, the pitch memory device 10 is equipped with an elongated support base 11 (support structure) that extends in a direction perpendicular to the longitudinal direction of the bed 100 when installed on the bed 100. The support base 11 has an elongated lower base plate 12, an upper base plate 13, and a pipe-shaped support column 14 interposed between these base plates 12 and 13.
[0032] As shown in Figures 4 and 8, the pitch memory device 10 comprises four slide guides 15 fixed to the upper surface of the support base 11 corresponding to the four lower threaded reinforcing bars 4 of the precast beam 1A, a carriage 16 slidably supported on each slide guide 15, and a threaded member 17 rotatably supported on each carriage 16.
[0033] The four slide guides 15 are installed at intervals along the longitudinal direction of the support base 11 and have guide portions 15a that protrude upward. The guide portions 15a extend in a direction perpendicular to the longitudinal direction of the support base 11 (i.e., in the axial direction of the threaded reinforcing bar 4, which will be described later). A groove 16a is formed in the lower part of the carriage 16 that fits into the guide portions 15a, thereby allowing the carriage 16 to slide in the axial direction of the threaded reinforcing bar 4.
[0034] The screw member 17 extends in the axial direction of the screw reinforcing bar 4 and, as shown in Figure 6, has a rotating portion 17a with a cylindrical surface formed in the axial center and first and second male threaded portions 17b and 17c formed on both sides in the axial direction. The rotating portion 17a of the screw member 17 is rotatably supported in a rotation support hole 16b formed in the upper part of the carriage 16. The rotating portion 17a and the rotation support hole 16b have smaller diameters than the male threaded portions 17b and 17c, thereby preventing the screw member 17 from moving axially relative to the carriage 16.
[0035] The male threaded portions 17b and 17c of the screw member 17 have the same outer diameter and pitch as the threaded reinforcing bar 4. The lengths of the male threaded portions 17b and 17c are equal. That is, the lengths from the axial center of the carriage 16 (the axial center of the rotating portion 17a of the screw member 17) to the end faces of the male threaded portions 17b and 17c are equal. This length is indicated by the symbol L in Figure 5. Length L is half the total length of the screw member 17.
[0036] As shown in Figure 7, a screw hole 16m is formed in the lower part of the carriage 16. By screwing in the first fixing screw 18 (first fixing means) which is screwed into this screw hole 16m, the tip of the first fixing screw 18 contacts the guide portion 15a of the slide guide 15, thereby preventing the carriage 16 from sliding. A screw hole 16n is also formed on the upper part of the carriage, and by screwing in the second fixing screw 19 (second fixing means) which is screwed into this screw hole 16n, the tip of the second fixing screw 19 comes into contact with the rotating part 17a of the screw member 17, thereby preventing the rotation of the screw member 17.
[0037] <Process for memorizing the pitch of threaded reinforcing bars in pre-assembled precast beams> As shown in Figure 2, in the process of storing the pitch of the threaded reinforcing bars 4 of the pre-assembled precast beam 1A, the pitch storage device 10 is installed at a predetermined position away from the precast beam 1A at one end of the bed 100 (the right end in the figure). Specifically, as shown in Figure 4, through holes 12a are formed at both ends of the lower base plate 12 of the support base 11 of the pitch storage device 10, and the device is fixed by screwing fixing screws (not shown) that pass through these through holes 12a into screw holes (not shown) of the bed 100. As a result, as shown in Figure 9, the four screw members 17 are arranged coaxially with the four threaded reinforcing bars 4 of the lower section of the precast beam 1A.
[0038] The pitch memory device 10 needs to be positioned with high precision in the axial direction of the threaded reinforcing bars 4 relative to the precast beam 1A. Therefore, as shown in Figure 4, linear positioning marks 12x are displayed at the center position (specific position) in the width direction of the lower base plate 12 of the support base 11 of the pitch memory device 10. On the other hand, a linear first reference mark 100x is displayed at the right end of the bed 100.
[0039] In this embodiment, the extension of the positioning mark 12x passes through the center of the four slide guides 15 when viewed from directly above. The first reference mark 100x indicates the first reference position R1. The first reference position R1 is set as follows: First, the first coupler nut center position C1 is defined as a position located at a distance M from the end face of the precast beam 1A installed on the bed 100. Here, M is the distance from the end face of the precast beam 1A to the design axial center 7c of the coupler nut 7 when the precast beam 1A is installed at the construction site, as described above. The first reference position R1 is set at a position further away from the first coupler nut center position C1 by half the axial length L of the screw member 17 relative to the precast beam 1A.
[0040] The support base 11 is positioned so that the positioning mark 12x aligns with the first reference mark 100x. Since there is radial play between the through hole 12a of the lower base plate 12 and the fixing screw, it is possible to align the positioning mark 12x with the reference mark 100x with high precision.
[0041] In the positioning state of the support base 10 described above, in the basic position where the axial centers of the carriage 16 and screw member 17 coincide with the extension line of the positioning mark 12x, the tip surface of the first guide portion 17b coincides with the center position C1 of the first coupler nut.
[0042] As shown in Figure 9, the design projection length of the threaded reinforcing bar 4 of the precast beam 1A is such that the tip surface of the threaded reinforcing bar 4 is, for example, 10 mm backward from the center position C1 of the first coupler nut, and this position is undefined within the tolerance range. First, slide the carriage 16 toward the threaded reinforcing bar 4 as indicated by the arrow, and bring the end face of the first male threaded portion 17b of the threaded member 17 into contact with the tip surface of the threaded reinforcing bar 4, as shown in Figure 10. Note that in Figure 9, the carriage 16 and threaded member 17 are in a basic position where their center positions coincide with the positioning mark 12x, but they may also be slid toward the reinforcing bar 4 from a position to the right of this basic position in the figure.
[0043] As shown in Figure 10, simply joining the first male threaded portion 17b of the screw member 17 to the threaded reinforcing bar 4 does not result in a matching pitch. Therefore, by rotating the screw member 17 as indicated by the arrow, the first male threaded portion 17b is adjusted to match the pitch of the threaded reinforcing bar 4, as shown in Figure 11. It is preferable to use a gauge 20 at this time. This gauge 20 has a semi-cylindrical shape obtained by splitting a cylindrical nut in half, and has a female threaded portion 21 that can be screwed onto the threaded reinforcing bar 4 and the first male threaded portion 17b without any play. By placing this gauge 20 over the threaded reinforcing bar 17 and the male threaded portion 17b, it is possible to confirm that the pitch of both is matched with high precision.
[0044] After the pitch adjustment process described above is completed, the first fixing screw 18 is screwed in to prevent the carriage 16 from sliding, and the second fixing screw 19 is screwed in to prevent the screw member 17 from rotating. As a result, the pitch memory device 10 stores the axial position and pitch of the screw reinforcement bars 4 of the pre-assembled precast beam 1A according to the principle described later. Note that fixing with the first fixing screw 18 may be performed before adjusting the rotation of the screw member 17.
[0045] <Process for adjusting the pitch of threaded reinforcing bars in the post-assembly reinforcing cage> As shown in Figure 3, the pre-assembled precast beam 1A is removed from the bed 100, the reinforcing cage 2 of the later-assembled precast beam 1B is installed in the formwork 101, and a pitch memory device 10 that stores the pitch of the pre-assembled precast beam 1A is installed in a predetermined position on the left side of the formwork 101, and the process of adjusting the pitch of the threaded reinforcing bars 4 shown in Figures 12 and 13 is performed.
[0046] First, the positioning mark 12x displayed on the lower base plate 12 of the pitch memory device 10 is aligned with the second reference mark 100y (shown only in Figure 12) displayed on the left end of the bed 100, and the pitch memory device 10 is fixed to the bed 100. This process is the same as the pitch memory process for the threaded reinforcing bars 4 of the pre-assembled precast beam 1A described above, so a detailed explanation is omitted.
[0047] The second reference mark 100y used in this pitch adjustment process indicates the second reference position R2. The second reference position R2 is set as follows: First, the second coupler nut center position C2 is set at a distance M from the reinforcing cage 2 (more precisely, the inner surface 101x of the formwork 101) for the precast beam 1B installed on the bed 100. Here, M is the distance from the end face of the precast beam 1B to the design axial center 7c of the coupler nut 7 when the precast beam 1B is installed at the construction site, as described above. The second reference position R2 is set at a position further away from the second coupler nut center position C2 by half the axial length L of the screw member 17 relative to the reinforcing cage 2 of the precast beam 1B.
[0048] When the positioning mark 12x of the pitch memory device 10 is aligned with the second reference mark 100y, the second male threaded portion 17c of the pitch memory device 10 reproduces the end of the threaded reinforcing bar 4 of the pre-assembled precast beam 1A at the joint 6. This is because, in the pitch memory process described above, the distance that the first male threaded portion 17b advanced from the center position C1 of the first coupler nut to reach the threaded reinforcing bar 4 appears in this pitch matching process as the amount that the second male threaded portion 17c retreats from the center position C2 of the second coupler nut, and the pitch of the threaded reinforcing bar 4 of the pre-assembled precast beam 1A appears as the pitch of the second male threaded portion 17c via the first male threaded portion 17b. Therefore, as shown in Figure 12, by adjusting the position of the threaded reinforcing bar 4, which is coaxial with the threaded member 17, in the axial direction (indicated by the arrow), and matching its pitch with the second male threaded portion 17c as shown in Figure 13, the pitch of the threaded reinforcing bars 4 of the precast beams 1A and 1B will match at the construction site, and as shown in Figure 1, the threaded reinforcing bars 4 of the precast beams 1A and 1B can be connected using the coupler nut 7. As shown in Figure 13, here too, by placing the semi-cylindrical gauge 20 across the second male threaded portion 17c and the threaded reinforcing bar 4, high-precision pitch matching can be confirmed.
[0049] The present invention is not limited to the above embodiments, and various forms can be adopted. In the above embodiment, if the precast beam is a structure in which not only the lower threaded reinforcing bars but also the upper threaded reinforcing bars 5 are embedded in the concrete, the support structure of the pitch memory device will be gate-shaped and will have a horizontal support portion extending in a direction perpendicular to the upper threaded reinforcing bars. A slide guide will be provided on the lower surface of this support portion. The slide guide may be integrated with the support structure and constitute a part of this support structure. The process of memorizing the pitch of the threaded reinforcing bars in pre-assembled precast members may be performed before setting the reinforcing cage in the formwork and pouring the concrete. This invention can also be used to adjust the pitch of threaded reinforcing bars in precast members other than beams. [Industrial applicability]
[0050] This invention can be applied to things like adjusting the pitch of threaded reinforcing bars in precast beams. [Explanation of symbols]
[0051] 1A Pre-assembled precast beam (pre-assembled precast member) 1B Sound-forming precast beam (post-assembly precast member) 2. Reinforced iron cage 4. Threaded reinforcing bars 6. Joint 6c Center of the joint 7. Coupler Nut 7c Axial center of the coupler nut in the joint 10 Pitch memory 11 Support stand (support structure) 12x Positioning Marks 15 Slide Guide 16 Carriage 17 Screw component 17a Rotating part 17b 1st male thread part 17c 2nd male thread part 18. First fixing screw (first fixing means) 19. Second fixing screw (second fixing means) 20 gauge 21 Female thread 100 beds 100x First Standard Mark 100 yards, second reference mark C1 First coupler nut center position C2 Second coupler nut center position R1 1st reference position R2 2nd reference position
Claims
1. A pitch memory device for storing the pitch of threaded reinforcing bars that are the main reinforcement of pre-assembled precast members or reinforcing cages, Support structure and A slide guide provided on the support structure, The slide guide includes a carriage that is slidably supported in the axial direction of the threaded reinforcing bar, A first fixing means for fixing the carriage to the slide guide in a way that prevents it from sliding, A screw member extending in the axial direction of the threaded reinforcing bar, comprising a rotating portion rotatably supported by the carriage, and first and second male threaded portions formed on both axial sides of the rotating portion and protruding from the carriage, wherein the first and second male threaded portions have the same diameter and pitch as the threaded reinforcing bar, and the pitches of the screw member are aligned with each other across the rotating portion, A second fixing means for fixing the screw member to the carriage in a way that prevents rotation, Equipped with, A pitch storage device for threaded reinforcing bars, characterized in that the end face of the first male thread portion can be joined to the tip face of the threaded reinforcing bar by sliding the carriage, the pitch of the first male thread portion can be matched to the pitch of the threaded reinforcing bar by rotating the screw member in this joined state, the pitch of the threaded reinforcing bar can be stored by fixing the carriage to the slide guide with the first fixing means and fixing the screw member to the carriage with the second fixing means.
2. The pitch storage device for screw reinforcing bars according to claim 1, characterized in that the protrusion lengths of the first and second male screw portions from the carriage are equal.
3. The first fixing means includes a first fixing screw that is screwed into the carriage and whose tip contacts the slide guide, The pitch storage device for screw reinforcing bars according to claim 1, characterized in that the second fixing means includes a second fixing screw that is screwed into the carriage and whose tip contacts the rotating portion of the screw member.
4. In order to enable the connection of threaded reinforcing bars of pre-assembled and later-assembled precast members facing each other across a joint at a construction site using coupler nuts, a method for matching the pitch of threaded reinforcing bars of pre-assembled and later-assembled precast members using the threaded reinforcing bar pitch memory device described in claim 1, The axial center position of the coupler nut with respect to the precast member of the first assembly is defined as the first coupler nut center position, and the axial center position of the coupler nut with respect to the precast member of the second assembly is defined as the second coupler nut center position. A pitch storage step involves positioning the support structure of the pitch storage device at a first reference position where its specific position is separated from the center position of the first coupler nut by a distance equivalent to half the axial length of the screw member relative to the pre-assembled precast member or reinforcing cage, and storing the pitch of the screw reinforcing bars of the pre-assembled precast member or reinforcing cage by the sliding of the carriage and the rotation of the screw member. Next, the support structure of the pitch memory device is positioned at a second reference position where the specific position is a distance from the center position of the second coupler nut to the reinforcing cage for the later assembled precast member, corresponding to half the axial length of the screw member, and the screw reinforcing bars of the reinforcing cage for the later assembled precast member are positioned in a pitch adjustment step to match the pitch of the second male screw portion of the screw member. A method for adjusting the pitch of threaded reinforcing bars, characterized by having the following features.
5. The method for adjusting the pitch of threaded reinforcing bars according to claim 4, characterized in that the specific position of the support structure is at the center of the threaded reinforcing bars in the axial direction within the support structure.
6. Prepare the threaded reinforcing bar and the semi-cylindrical gauge having female threads with the same pitch as the first and second male threaded portions. In the pitch memory step, the pitch alignment between the threaded reinforcing bar of the pre-assembled precast member or reinforcing cage and the first male threaded portion of the threaded member is confirmed by placing the gauge over the threaded reinforcing bar and the first male threaded portion. The method for matching the pitch of threaded reinforcing bars according to claim 4, characterized in that, in the pitch matching step, the pitch matching between the threaded reinforcing bars of the reinforcing cage for the later assembled precast member and the second male threaded portion of the threaded member is confirmed by placing the gauge over the threaded reinforcing bars and the second male threaded portion.
7. A positioning mark is displayed at a specific position on the support structure, a first reference mark is displayed at the first reference position on one end of the precast bed, and a second reference mark is displayed at the second reference position on the other end of the bed. The method for adjusting the pitch of a threaded reinforcing bar according to claim 4, characterized in that, in the pitch memory step, the support structure of the pitch memory device is positioned by aligning the positioning mark with the first reference mark, and in the pitch adjustment step, the support structure of the pitch memory device is positioned by aligning the positioning mark with the second reference mark.
8. The method for adjusting the pitch of threaded reinforcing bars according to claim 4, characterized in that the axial center of the coupler is located in the center of the joint, and the distance from the pre-assembled precast member to the center position of the first coupler nut is equal to the distance from the post-assembled precast member to the center position of the second coupler nut.