JP2019044902A - Manufacturing method of anchor bolt - Google Patents

Abstract

To provide a manufacturing method of an anchor bolt capable of attaining reduction of cost.SOLUTION: In accordance with a manufacturing method of an anchor bolt, multiple abutment parts 12 of an expanded member 8 externally fitted to a taper member 7 of the anchor bolt are molded from a synthetic resin integrally with a bridge part 13. In a core 31 of a metal mold 20 for molding the expanded member 8, a slope 35 for molding an inner surface 11 of each of the abutment parts 12 is formed in an inclined shape closer to an axis of the core 31 as it gets closer to a proximal end side in accordance with the inclination of the inner surface 11 of the abutment part 12. After the expanded member 8 is molded, a movable metal mold 24 and a stationary metal mold 22 are separated, sliders 25a and 25b are moved by sliding and opened and in such a state, the molded expanded member 8 is pushed by an ejector pin 32, such that the expanded member 8 is taken out of the core 31 while spreading the abutment parts 12 outwards along the slope 35 of the core 31.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a method of manufacturing an anchor bolt which is inserted and fixed in a mounting hole provided in a wall surface such as a rock wall or a concrete ceiling.

  As said anchor bolt, what is shown by patent document 1, for example is proposed. In the anchor bolt, there are provided a tapered member in which a female screw threadingly engaged with the male screw of the rod is provided in a penetrating manner, five contact portions arranged circumferentially along the outer peripheral surface of the tapered member, and each contact And a bridge portion which connects the respective portions (see FIG. 1 of Patent Document 1).

  The tapered member is formed five in the circumferential direction along the outer peripheral surface of the tapered member so as to extend in the axial direction so as to reach each contact portion, and the inclined surface of the tapered member is on the proximal side The tapered member is formed to be inclined toward the axial direction as it goes to the side opposite to the bridge portion. The inner surface of each contact portion is formed to be inclined according to the inclined surface of the taper member.

  Then, by moving the rod in the direction of pulling out from the mounting hole, the tapered member is also moved to the mounting hole side along with it, and the inclined inner surface of each contact portion is pushed by the inclined surface of the tapered member. Thus, the outer peripheral surface of each contact portion is pressed against the inner peripheral surface of the mounting hole, and the anchor bolt is fixed to the mounting hole.

  By the way, in the anchor bolt, it is considered to mold the contact portion and the bridge portion with resin in order to reduce the cost.

JP 2017-57940 A

  However, after each contact portion and the bridge portion are individually molded with resin, if each contact portion is connected to the bridge portion by means such as welding or an adhesive, it takes much time and effort to manufacture the anchor bolt. It takes time and time.

  As a countermeasure, it is conceivable to integrally mold each contact portion and the bridge portion. In that case, a core for molding the inner surface side of each contact portion and the bridge portion is fixed to a mold (movable mold). Since the core is in a state of being surrounded by an integrally molded product consisting of each contact portion and the bridge portion after molding, the integrally molded product is pulled out from the bridge portion side with respect to the core.

  The outer surface of the core is formed to be inclined according to the inclination of the inner surface of the contact portion, so the width of the tip side (fixed mold side) is smaller than the width of the base end side of the core (movable mold side). Become bigger (become thicker). Therefore, there is a problem that when the integral molded product is removed from the core, the contact portion is engaged with the core, and the integral molded product can not be easily removed from the mold.

  The present invention is provided for the purpose of solving such problems, and it is an object of the present invention to provide a manufacturing method capable of achieving cost reduction of anchor bolts. Another object of the present invention is to provide a method of manufacturing an anchor bolt capable of reliably taking out the integral molded product from a mold even if each contact portion of the anchor bolt and the bridge portion are integrally molded with a resin.

In order to solve such a disadvantage, according to the present invention, the tapered member 7 is formed with a plurality of inclined surfaces 10 which are inclined toward the central axis toward the proximal end on the outer peripheral surface. The spreader member 8 has the spreader member 8 of the taper member 7 as the inner surface 11 is directed toward the tip end side so that the inner surface 11 abuts on each inclined surface 10 of the taper member 7 respectively. Each of the plurality of contact portions 12 inclined toward the central axis and the plurality of connection portions 13b extending from the edge of the main body portion 13a are elastically deformable such that the base end sides of the respective contact portions 12 are connected. A method of manufacturing an anchor bolt having various
Each contact portion 12 of the expansion member 8 and the bridge portion 13 are integrally formed of resin, and a mold 20 for molding the expansion member 8 includes a fixed mold 22 and a movable mold 24. And a pair of sliders 25a and 25b which can be formed by sliding on the outer peripheral side of each contact portion 12 of the expanding member 8 and can be opened by sliding movement, and fixed to the movable mold 24 of the expanding member 8 The core 31 has a core 31 for molding the inner side, and an ejector pin 32 for taking out the expander member 8 after molding from the core 31. The core 31 has contact parts of the expander member 8 on the outer periphery. It has a plurality of inclined surfaces 35 for molding the inner surface 11 of 12, and those inclined surfaces 35 conform to the inclination of the inner surface 11 of the contact portion 12 of the expanding member 8 and approach the proximal end side Each is formed in an inclined shape approaching the axis of the core 31, and the mold 20 is closed. In this state, the molten resin is filled into the cavity 26 of the mold 20 and molded, and after molding, the movable mold 24 and the fixed mold 22 are separated from each other, and the sliders 25a and 25b are slid and opened In that state, by pushing the formed expansion member 8 by the ejector pin 32, the expansion member 8 is taken out from the core 31 while each contact portion 12 spreads outward along the inclined surface 35 of the core 31. It is characterized by The anchor bolt is assembled by externally fitting the expansion member 8 taken out of the core 31 to the taper member 7.

  The taper member 7 in this case includes one in which the male screw 3 formed on the rod 4 is screwed, and one in which the rod is integrated with the taper member 7 by welding or the like. The taper member 7 includes metal and synthetic resin. The expanding member 8 corresponds to one formed of a resin (synthetic resin) such as polyamide, polyethersulfone or polysulfone, and also includes one containing glass fiber, carbon fiber or the like in the resin. Here, the ejector pin 32 pushes the inner surface of the main body portion 13a of the bridge portion 13 of the expansion member 8 (the state of FIG. 10) or the tip of the contact portion 12 of the expansion member 8 (lower end in FIG. 10) The one that presses) corresponds etc.

  Further, on the inner surface of the main body portion 13a of the bridge portion 13 of the spreading member 8, a hemispherical bulge portion 13c is bulged, and in the fixed mold 22 of the mold 20, the bulge of the bridge portion 13 is The gate 28 for injecting the molten resin into the mold 20 can be positioned at a position facing the cavity portion 26a for molding the portion 13c. Here, the hemispherical shape of the bulging portion 13 c may be any as long as it forms a part of a spherical shape, and also includes one in which a part of the outer surface of the bulging portion 13 c is planar.

  Furthermore, the gate 28 may be protruded toward the cavity portion 26 a together with its peripheral portion 28 a. The peripheral portion 28 a corresponds to one surrounding the entire peripheral edge of the gate 28 or one in which a part of the peripheral portion 28 a is missing.

  Only one ejector pin 32 is arranged in the mold 20, the ejector pin 32 penetrates the core 31, and the tip of the ejector pin 32 has the shape of the outer surface of the bulging portion 13c of the bridge portion 13. It can be indented in the same spherical shape.

  In the anchor bolt according to the manufacturing method of the present invention, since each contact portion 12 of the expanding member 8 and the bridge portion 13 are integrally molded with resin, it is possible to reduce the labor and the like of the anchor bolt by that amount. As a result, the cost of the anchor bolt can be reduced.

  The core 31 of the mold 20 for molding the expansion member 8 approaches the axis of the core 31 as the inclined surface 35 of the core 31 approaches the proximal side with the inner surface 11 of the contact portion 12 The core 31 has a larger (wider) lateral width on the distal end side than on the proximal end side (see FIG. 10).

  In the manufacturing method of the present invention, when the sliders 25a and 25b of the mold 20 slide and open (see FIG. 6), the respective contact portions 12 of the expansion member 8 after molding interfere with the sliders 25a and 25b. It can spread outward of the core 31 without being done. Thereby, when the expansion member 8 is taken out from the core 31 of the mold 20 after molding, each contact portion 12 of the expansion member 8 spreads outward along the inclined surface 35 of the core 31 and the core 31 It is taken out without being used to. That is, in order to reduce the cost of the anchor bolt, even if each contact portion 12 of the expansion member 8 of the anchor bolt and the bridge portion 13 are integrally molded with resin, the integrally molded product is a mold 20 (core 31) can be taken out with certainty.

  When the gate 28 of the mold 20 is positioned at a position facing the cavity portion 26a for molding the bulging portion 13c of the bridging portion 13 of the expanding member 8, the cavity 26 is expanded in the cavity portion 26a Thus, the molten resin can be easily injected into the mold 20. Thereby, each contact part 12 of the anchor bolt and the bridge part 13 can be integrally molded reliably and rapidly.

  Furthermore, by providing the bulging portion 13c in the bridge portion 13 of the expanding member 8, for example, the rod 4 is screwed to the taper member 7, and the anchor bolt is provided on the wall surface 1 of the ceiling or the like. When the distal end of the rod 4 is brought into contact with the bulging portion 13c of the bridging portion 13 by inserting the mounting hole 2 from the spreading mechanism 5 side, the bulging portion 13c and the rod 4 substantially contact each other. The rod 4 can be easily rotated about the central axis.

  As a result, the tapered member 7 can be reliably moved to the opening side of the mounting hole 2 by screw action, and each inclined surface 10 of the tapered member 7 can be pressed firmly against the inner surface 11 of each contact portion 12. As a result, each contact portion 12 is pressed toward the inner peripheral surface 2 a of the mounting hole 2, and the anchor bolt is fixed to the mounting hole 2. That is, the anchor bolt can be firmly fixed to the mounting hole 2 as much as the rod 4 can be easily rotated.

  When the gate 28 protrudes toward the cavity portion 26a together with the peripheral portion 28a, the trace of the gate 28 is suppressed from jumping out to the surface of the main body portion 13a in the expanded member 8 after molding. Even if each contact portion 12 of the expansion member 8 of the anchor bolt and the bridge portion 13 are integrally formed of resin in order to reduce the cost of the anchor bolt, the appearance of the expansion member 8 of the anchor bolt is improved. be able to.

  When the tip of one ejector pin 32 penetrating the core 31 is formed into a spherical shape equal to the shape of the outer surface of the bulging portion 13 c of the bridge portion 13, for example, the expanding member 8 is removed from the core 31 Even when the expanding member 8 shakes when it is taken out, the bulging portion 13 c is firmly received by the recess of the ejector pin 32 so that the expanding member 8 can be surely taken out of the mold 20 by the ejector pin 32. it can.

It is a perspective view of an anchor bolt concerning a manufacturing method of the present invention. It is a perspective view of a taper member of an anchor bolt concerning a manufacturing method of the present invention. It is sectional drawing which shows the state at the time of inserting the anchor bolt concerning the manufacturing method of this invention to a mounting hole. It is sectional drawing which shows the state which fixed the anchor bolt concerning the manufacturing method of this invention to a mounting hole. It is sectional drawing which shows the state which closed the metal mold | die which shape | molds the expansion member of the anchor bolt concerning the manufacturing method of this invention. It is sectional drawing which shows the state which open | released the metal mold | die which shape | molds the expansion member of the anchor bolt concerning the manufacturing method of this invention. It is sectional drawing which shows the state which takes out the expansion member of the anchor bolt concerning the manufacturing method of this invention from a metal mold | die. It is a figure which shows the side of the core which shape | molds the expansion member of the anchor bolt concerning the manufacturing method of this invention, and the cross section of the one part. It is an AA line arrow directional cross-sectional view of FIG. It is sectional drawing for demonstrating the state at the time of taking out the expansion member of the anchor bolt concerning the manufacturing method of this invention from a core. It is sectional drawing which shows the state which closed the metal mold | die which shape | molds the taper member of an anchor bolt. It is sectional drawing which shows the state which open | released the metal mold | die which shape | molds the taper member of an anchor bolt. It is sectional drawing for demonstrating the operation | movement at the time of taking out the taper member of an anchor bolt from a core.

  An example of the anchor bolt concerning the manufacturing method of this invention is demonstrated. As shown in FIG. 4, the anchor bolt is inserted and fixed in a mounting hole 2 provided upward on, for example, a wall surface 1 of a ceiling made of concrete. As shown in FIG. 1, the anchor bolt has a cylindrical rod 4 with an external thread 3 formed on the outer peripheral surface, and an anchor bolt formed on the cylindrical inner surface 2a of the mounting hole 2 (see FIG. 4) And an expansion mechanism 5 for fixing to the

  The spreading mechanism 5 is, as shown in FIG. 3, a synthetic resin taper member 7 (FIG. 2) in which five planar inclined surfaces 10 obliquely extending in the axial direction are formed on the outer peripheral surface; And an expanding member 8 made of synthetic resin and fitted on the tapered member 7. Each inclined surface 10 of the taper member 7 is inclined so as to approach the central axis as it goes to the base end side (lower side in FIG. 3), and is disposed at equal intervals in the circumferential direction along the outer periphery of the taper member 7 doing. The taper member 7 is provided with a female screw 6 through which the male screw 3 of the rod 4 is screwed along the central axis thereof.

  As shown in FIG. 1 and FIG. 3, the expanding member 8 faces the inner surface 11 to the tip side (lower side in FIG. 3) so as to be able to abut (face contact) with each inclined surface 10 of the taper member 7. According to the above, five contact portions 12 inclined so as to approach the central axis of the taper member 7 and an elastically deformable bridge portion 13 connecting the respective contact portions 12 are configured.

  After the five connection portions 13b extend outward of the bridge portion 13 from the edge of the main body portion 13a, the bridge portion 13 is curved downward and the proximal end side of each contact portion 12 (upper side in FIG. 3) Are connected. A substantially hemispherical bulging portion 13 c is bulging (in FIG. 3, bulging downward) on the inner surface (the lower surface in FIG. 3) of the main body portion 13 a of the bridge portion 13.

  The outer peripheral surface 15 of each contact portion 12 is formed in a cylindrical surface shape similar to the inner peripheral surface 2 a of the mounting hole 2, and the outer peripheral surface 15 of each contact portion 12 is the inner peripheral surface of the mounting hole 2 Surface contact is possible with 2a. The rod 4 is formed of a metal such as stainless steel or a synthetic resin such as polyamide, and the taper member 7 and the expanding member 8 are made of a synthetic resin (resin) such as polyamide, polyethersulfone or polysulfone. Also, those containing glass fiber, carbon fiber and the like in the above-mentioned synthetic resin are included.

  Next, an example of a procedure for fixing the anchor bolt according to the present invention to the mounting hole 2 will be described. First, the anchor bolt is inserted to the back of the mounting hole 2 (the state of FIG. 4) in the posture (the posture of FIG. 3) with the spread mechanism 5 up. At that time, the tip (the upper end in FIG. 4) of the rod 4 is in contact with the bulging portion 13 c of the bridging portion 13.

  Then, for example, by rotating the rod 4 around the central axis of the rod 4 while keeping the rod 4 in contact with the bulging portion 13c of the bridge portion 13, the taper member 7 is screwed to the opening side of the mounting hole 2 (see FIG. Move down to 4). Then, each inclined surface 10 of the taper member 7 pushes the inner surface 11 of each contact portion 12, whereby each contact portion 12 moves to the inner peripheral surface 2 a side of the mounting hole 2 and the inner peripheral surface of the mounting hole 2 The anchor bolt is fixed to the mounting hole 2 by the friction between the outer peripheral surface 15 of each contact portion 12 and the inner peripheral surface 2 a of the mounting hole 2.

  For example, a bracket 18 (FIG. 4) for fixing equipment, piping, etc. is attached to the rod 4 of the anchor bolt, and a nut 19 is screwed to the lower side of the bracket 18, whereby the bracket 18 is fixed. It is fixed to the anchor bolt.

  Next, an embodiment of an injection molding die 20 for molding the expansion member 8 of the anchor bolt according to the manufacturing method of the present invention will be described. The injection molding die 20 is configured to integrally mold each contact portion 12 of the expansion member 8 and the bridge portion 13.

  That is, as shown in FIG. 5, the mold 20 is attached to the injection molding machine (not shown) via the stationary side attachment plate 21, and the injection molding machine via the movable side attachment plate 34. Mounted on the movable mold 24 driven (in the vertical direction in FIG. 5) by the injection molding machine, and a pair of sliding molds which can be opened in the lateral direction of FIG. It has sliders 25a and 25b. The sliders 25a and 25b mold the outer peripheral side of each contact portion 12 of the expansion member 8 and the outer peripheral side of a part of the lower portion of the connection portion 13b of the bridge portion 13. The fixed side mounting plate 21 has a locating ring 23 for alignment at the time of attachment to the injection molding machine.

  The fixed mold 22 includes a sprue 27 for pouring molten resin into the cavity 26 and a gate (pinpoint gate) 28 for injecting the molten resin flowing into the sprue 27 into the cavity 26 (see FIG. 8). And a pair of angular pins 29 and 29 for sliding the sliders 25a and 25b, respectively. The cavity 26 is formed across the fixed mold 22, the sliders 25 a and 25 b and the movable mold 24.

  The gate 28 is, as shown in FIG. 8, located at a portion of the cavity 26 facing the cavity portion 26 a for molding the bulging portion 13 c of the bridge portion 13. The gate 28 protrudes toward the cavity portion 26a together with the peripheral portion 28a. Thereby, a recess is formed on the upper surface of the main body portion 13a of the bridge portion 13 after molding, and even if a trace of the gate 28 is formed in the recess, the trace of the gate 28 is outside the surface of the main body portion 13a. It can be suppressed to fly out.

  A core 31 for molding the inner surface 11 side of each contact portion 12 of the expanding member 8 and the inner surface side of the bridge portion 13 is fixed to the movable mold 24 in an upright posture. The base end side (the lower end in FIG. 8) of the core 31 is fixed to the movable mold 24. The core 31 extends to the cavity 26 on the fixed mold 22 side.

  As shown in FIGS. 8 and 9, the core 31 has five inclined surfaces 35 on the outer periphery thereof, and the inclined surfaces 35 are aligned with the inclination of the inner surface 11 of the contact portion 12 to form a base. It forms in the shape of an inclination which approaches the axis of the core 31 concerned as approaching the end side (the lower side in FIG. 8).

  Further, in the core 31, five pieces extending in the axial direction (vertical direction in FIG. 8) of the core 31 along the boundaries of the respective inclined surfaces 35 of the core 31 for dividing and molding the respective contact portions 12 A linear projection 36 is provided. As shown in FIG. 9, the outer peripheral surface 36a of the linear projection 36 contacts the inner surface of the cavity 26 of the sliders 25a and 25b, so that the contact portions 12 are formed in a separated state.

  The core 31 is formed such that the circumferential center of one contact portion 12 is positioned at the circumferential center of the spherical cavity 26 of one slider 25a (see FIG. 9). Thereby, for example, by forming a marking such as a product number in a convex shape on the inner surface of the one slider 25a facing the center of the one contact unit 12, the product number etc. is one contact unit 12 It can be formed concave on the outer surface of

  In the movable mold 24, a single ejector pin 32 for taking out the expansion member 8 after molding is disposed. The ejector pin 32 vertically penetrates the core 31 along the axis of the core 31. The base end (lower end in FIG. 5) of the ejector pin 32 is fixed to an ejector plate 33 provided on the movable mold 24 side. The ejector plate 33 is fixed to a lift bar 38 of an ejector drive (not shown) of the injection molding machine, and is driven vertically by the lift bar 38.

  As shown in FIG. 8, the tip of the ejector pin 32 is recessed in a spherical shape equal to the shape of the outer surface of the bulging portion 13c, thereby molding the central portion of the outer surface of the bulging portion 13c.

  Subsequently, an embodiment of a method of molding the expansion member 8 of the anchor bolt according to the manufacturing method of the present invention will be described. That is, in a state in which the injection molding die 20 of the expansion member 8 is closed (the state of FIG. 5), the molten resin is filled into the cavity 26 of the die 20 via the sprue 27 and the gate 28 Do.

  After the molding, the movable mold 24 is lowered to be separated from the fixed mold 22 (the state of FIG. 6). At that time, as shown in FIG. 6, the sliders 25a and 25b slide in the left and right direction by the angular pins 29 and 29 and are opened, and the core 31 is lowered together with the movable mold 24. Subsequently, the ejector plate 33 is driven to ascend by the lift bar 38, and the ejector pin 32 ascends to push the molded expansion member (molded product) 8 and thereby the expansion member 8 is removed from the core 31 (see FIG. 7)).

  At that time, the contact portions 12 after molding respectively enter the location of each inclined surface 35 of the core 31, but when taking out the expansion member 8 after the molding from the core 31, the sliders 25a and 25b Since it is open, as shown in FIG. 10, each contact portion 12 easily spreads outward along the inclined surface 35 of the core 31, and the expanding member 8 is taken out without being stuck to the core 31. Thereby, molding of the expansion member 8 is completed. The anchor bolt is assembled by externally fitting the expanding member 8 taken out of the core 31 to the taper member 7.

  Subsequently, an embodiment of a method of molding the taper member 7 of the anchor bolt will be described. An injection molding die 39 for molding the taper member 7 is, as shown in FIG. 11, molded with a fixed die 43 having a sprue 40 and a gate 41, a movable die 45, and the female screw 6 of the taper member 7. And an externally threaded core 46 for The core 46 vertically penetrates the movable mold 45, and is connected to a rotational drive (not shown) of the injection molding machine. A cavity 42 for molding the taper member 7 is formed across the fixed mold 43 and the movable mold 45. The core 46 forms an external thread only in the portion located in the cavity 42. The gate 41 is provided at a position near the edge of the upper surface of the taper member 7 (rightward in FIG. 11) in order to avoid the female screw 6 of the taper member 7.

  With the injection molding mold 39 of the taper member 7 closed (the state of FIG. 11), the molten resin is filled into the cavity 42 via the sprue 40 and the gate 41 and molded. After the molding, the movable mold 45 is lowered to be separated from the fixed mold 43 (the state of FIG. 12). Next, by rotating the core 46 about the axis, as shown in FIG. 13, the tapered member 7 after molding is lifted by a screw action to be released from the movable mold 45. Thereby, molding of the taper member 7 is completed. The rod 4 is screwed to the tapered member 7 and assembled.

  11 to FIG. 13, elements having the same functions as those in FIG. 5 to FIG. 7 are assigned the same reference numerals as in FIG. 5 to FIG.

  The number of inclined surfaces 10 formed on the outer peripheral surface of the taper member 7 may be three, four, six, or the like. The number of contact portions 12 is set accordingly. In the above description, the expanding member 8 and the taper member 7 are molded of synthetic resin, but the taper member 7 may be formed of metal such as stainless steel.

Reference Signs List 7 taper member 8 expanding member 10 inclined surface of taper member 11 inner surface of contact portion 12 contact portion 13 bridge portion 13a main portion 13b of bridge portion connection portion 13c of bridge portion 13c bulge portion of bridge portion 20 gold for injection molding Mold 22 Fixed mold 24 Movable mold 25a, 25b Slider 26 Cavity 26a Cavity part 28 Gate 28a Gate peripheral part 31 Core 32 Ejector pin 35 Core inclined surface

Claims (4)

A taper member (7) having a plurality of inclined surfaces (10) formed on the outer peripheral surface so as to approach the central axis as it goes to the base end side, and an expanding member externally fitted to the taper member (7) And (8),
The expanding member (8) has the tapered member (7) in such a manner that the inner surface (11) is directed to the tip side so that the inner surface (11) abuts on each inclined surface (10) of the tapered member (7). A plurality of contact portions (12) inclined to approach the central axis of b) and a plurality of connection portions (13b) extending from the edge of the main body portion (13a) A method of manufacturing an anchor bolt having an elastically deformable bridge portion (13) connecting proximal ends of
Each contact portion (12) of the expanding member (8) and the bridge portion (13) are integrally molded of resin,
In the mold (20) for molding the expanding member (8), the fixed mold (22), the movable mold (24), and the outer peripheral side of each contact portion (12) are molded and the slide A pair of sliders (25a) and (25b) which can be moved and opened, and a core (31 for fixing the inner surface side of the expanding member (8) which is fixed to the movable mold (24) And an ejector pin (32) for taking out the molded expansion member (8) from the core (31),
The core (31) has a plurality of inclined surfaces (35) for molding the inner surface (11) of each contact portion (12) on its outer periphery, and the inclined surfaces (35) are It is formed in the shape of a slope which approaches the axis of the core (31) as it approaches the proximal end side according to the slope of the inner surface (11) of the contact portion (12),
With the mold (20) closed, the molten resin is filled into the cavity (26) of the mold (20) and molded, and after molding, the movable mold (24) and the fixed mold ( 22) are separated from each other, and the sliders (25a) and (25b) are slid open.
In this state, by pushing the molded expansion member (8) by the ejector pin (32), each of the contact portions (12) of the expansion member (8) is the core (31). A method of manufacturing an anchor bolt characterized in that the anchor bolt is taken out from the core (31) while spreading outward along the inclined surface (35). A hemispherical bulging portion (13c) is expanded on the inner surface of the main body portion (13a) of the bridge portion (13) of the expanding member (8);
In the fixed mold (22) of the mold (20), the mold (20) is provided at a location facing a cavity portion (26a) for molding the bulging portion (13c) of the cross-linked portion (13). 2. A method of manufacturing an anchor bolt according to claim 1, characterized in that a gate (28) for injecting the molten resin is positioned therein.   The method of manufacturing an anchor bolt according to claim 2, wherein the gate (28) protrudes toward the cavity portion (26a) together with its peripheral portion (28a). Only one ejector pin (32) is disposed in the mold (20),
The ejector pin (32) penetrates the core (31),
The tip of the ejector pin (32) is concavely formed in a spherical shape equal to the shape of the outer surface of the bulging portion (13c) of the bridge portion (13). Method of manufacturing anchor bolt.