JP4234276B2 - Cold drilling device for cold-formed eyebolts - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a cold drilling device for a cold-formed eyebolt, which is a support bolt for suspending a building panel or the like or fixing it to the building frame side.
[0002]
[Prior art]
The structure of the so-called clamping eyebolt that suspends a commonly used building panel or the like and fixes it to the building frame side is to flatten the head of the bolt body of a predetermined diameter once and then center the flat spherical head. Is a predetermined hole. In this case, conventionally, as this kind of drilling work, a drilling work with a drill and a punching work with a punch are known. However, in the former drilling, drilling takes time and is inefficient. For example, when a φ12 hole is drilled with a drill blade in a flat spherical head having a thickness of 12 mm in a bolt body made of SWCH material or the like, about 700 to 800 holes per unit per day by hand. Dawn work is the limit. At this time, the wear of the drill blade itself is severe, and polishing is required every time a predetermined number (about 2000) is cut, and this is also a troublesome operation. Even if the cutting process is automated, the number of drilling is about 2000 at most.
[0003]
For this reason, as the mass production type for punching eyebolts, the one that uses the latter punch-type punching process, which does not take time, has become the mainstream.
[0004]
[Problems to be solved by the invention]
However, in the punching work of press working using conventional press machines, the mold that receives the flat spherical head formed on the bolt body does not have a special configuration, and the outer circumference of the flat spherical head is simply Just set in a die with a female receiving groove that is large enough to fit, and punch a hole with a predetermined diameter on the flat spherical head supported by this die with a punch that descends from an upper position. Is. That is, the female receiving groove of this type of mold has a receiving groove shape having an area that allows the periphery of the flat spherical head to be tightly fitted, and a bulging portion that deforms the flat spherical head by punch pressure ( The amount of stretch of the material) is not expected.
[0005]
Thus, in the punching process by punching under the condition that the outer periphery of the flat spherical head is regulated by the female receiving groove, a very large pressing pressure is required to obtain a hole with a predetermined diameter. Unless a very large pressing pressure is applied, a hole having a predetermined diameter cannot be formed. This is because the thickness of the flat spherical head formed in a separate process in advance in consideration of safety is set smaller than the diameter of the bolt body (shaft diameter) as a hole in actual press work. A flat spherical head is used. For this reason, as a finished eyebolt product, the flat head is too thin, reducing the product value.
[0006]
In general, when punching a steel plate by punching with a round punch, the relationship between the plate thickness and the hole is limited to a hole diameter and a plate thickness of the same dimension at the maximum. However, when drilling the flat spherical head of the bolt body using a conventional mold, the conventional mold has a receiving shape with an area that allows the flat spherical head to fit tightly to the end. Considering safety, the plate thickness of the flat spherical head is limited to less than 2/3 of the hole diameter. Therefore, the flat spherical head is crushed so that the flat spherical head becomes thinner than the bolt diameter so that it can be easily punched by press working, and the spread thin flat spherical head is used. In general, the shaft diameter of the bolt body and the hole diameter provided in the flat spherical head are designed to be substantially the same, so that the plate thickness of the widened thin spherical head is less than 2/3 of the hole diameter. That is, the hole diameter of the hole provided in the spread thin flat spherical head has a dimension exceeding 3/2 times the plate thickness.
[0007]
For example, as shown in FIG. 8A, in a bolt body d having a predetermined shaft diameter, the thickness of the flat spherical head f that opens a fixed eye hole e is smaller than the diameter of the bolt body d. One side is crushed with a press in advance to form a thin flat spherical head f ′, or a flat spherical head so that the thin flat spherical head f ′ comes to the center of the bolt body d as shown in FIG. The part f is crushed from both sides to make it easier to open the eye hole e. Thereafter, the thin flat spherical head f 'is placed on a predetermined press stand, and a punching operation is performed by a punch that descends. In the eyebolt structure obtained by punch-type punching according to this conventional method, the flat spherical head inevitably becomes a plate thickness (thin) shape that is smaller than the diameter of the bolt body, and further spreads thin. The hole provided in the flat spherical head has a disadvantage that it is inferior in strength because it has a dimension exceeding 3/2 times the plate thickness. Moreover, even if it is a metal fitting that withstands strength, the appearance is poor and the product value is lowered.
[0008]
For this reason, for example, as shown in FIG. 8C, the eye hole e can be directly opened in the flat spherical head f that is at least equal to or slightly larger than the diameter dimension of the bolt body d. Since the eyebolt as a whole increases the sense of weight and increases the product value, the development of such a new product is awaited.
[0009]
Further, if the press machine has a constant capacity, the set position is shifted due to the crushing spread by the press, and the punch is moved in the direction of displacement of the member, which causes damage to the punch itself. In addition, the vertical punching hole of the washer through which the lowering punch is inserted has a vertical lip structure, so the press pressure is applied properly, and the lip is easily cracked and damaged. .
[0010]
In view of the above circumstances, the present invention uses a die that receives the flat spherical head of the bolt body having a slightly larger shape that anticipates a portion that is crushed and swelled by the press pressure, so that the shaft diameter dimension of the bolt body is equal to or greater than It is an object of the present invention to provide a cold drilling device for a cold-formed eyebolt that enables a punched hole in a spherical head or a flat spherical head slightly larger than an approximate size and solves the above-mentioned problems.
[0011]
[Means for Solving the Problems]
The present invention according to claim 1 relates to an apparatus for forming a cold-formed eyebolt, and in a cold drilling apparatus for drilling a hole of a predetermined diameter in a spherical head or a flat spherical head of a bolt body. The table-side mold that receives half of the spherical head or flat spherical head of the bolt body is a slightly larger female groove that looks at the bulging portion where this spherical head or flat spherical head collapses due to punch pressure and bulges to the outer periphery. In addition to forming, an inclined surface for pressure relief is provided at the rim portion of the vertical hole formed in the center of the female groove portion, and a horizontal support groove portion for receiving the shaft portion of the bolt body is provided at one end of the female groove portion. In addition, the male mold disposed above the axial line of the vertical punch hole is provided with a punch having a taper surface for preventing misalignment at the periphery of the lower end.
[0017]
The punch apparatus of the present invention, a mold for receiving the spherical head or flattened spherical head, spherical head or flattened spherical head is loosely fitted a slightly larger expected bulging fraction member collapsing a punch pressure Since it becomes a female mold receiving groove, plastic deformation that bulges up to the larger female mold receiving groove is made by the punch pressure descending to the spherical head or flat spherical head set in the female mold receiving groove, Punching with a punch can be performed even under thick conditions where the thickness of the spherical head or the flat spherical head is equal to or greater than the diameter dimension of the bolt body or a little smaller approximate dimension. At this time, since the outer peripheral wall of the female receiving groove bulges and restrains against the swelling of the member due to punch pressure, the center position of the spherical head or the flat spherical head is not displaced, and the predetermined hole is punched by punch lowering. Can do. Also, for the thickness D ′ of the spherical head or the flat spherical head, a hole is punched with a hole diameter dimension φ in the range of 2 / 3D ′ to 3 / 2D ′, even in consideration of safety. Can do.
[0018]
In addition, the edge of the vertical punch hole has a downward inclined punching surface for evacuating the punch pressure, and the punch side has a taper surface for preventing misalignment at the lower end edge. Because it faces the position, it does not cause contact displacement, and in combination with the inclined surface of the hole edge of the female part, press pressure escapes (impact buffering), and the impact of the hole hole edge is not received. The so-called mold is good without cracking or breaking.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, it will be as follows if one Example of the cold forming eyebolt of this invention and its cold drilling apparatus is described based on figures.
[0020]
1 to 7 show an embodiment of a cold drilling device using an intermediate molded part in which a flat spherical head is formed in advance on the head of a bolt body, and a cold molded eyebolt manufactured by the device. Reference numeral 1 denotes a receiving groove 1a into which the lower half of the flat spherical head 3 of the bolt body 2 to be horizontally set is fitted in the center of the upper surface, and a bulging portion that bulges to the outer periphery where the flat spherical head 3 is crushed by the press pressure of the punch lowering. A table side mold (lower mold) which is formed in a slightly larger curved female groove portion 4 to allow for (amount) and a vertical punched hole 5 of a predetermined diameter is drilled downward at the center position of the female groove portion 4 Thus, the mold 1 is fixed to the table portion 6a side of the press machine 6 by appropriate means. In this case, the forming gap a which is the bulging width of the flat spherical head 3 fitted into the curved female groove 4 is a small gap of about 0.3 mm, for example. In addition, a downwardly inclined pressure-relief surface 7 for forming a downward pressure relief is formed in a flat portion b of about 1 mm formed in the rim 5a of the vertical punch hole 5 in the central portion of the female groove portion 4. However, it is a so-called sagging (see FIG. 4). The inclination angle α of the inclined drawing surface 7 is set to about 5 °, for example. The diameter of the vertical punch hole 5 is slightly larger than the diameter of the shaft-like punch 8 attached to the punch plate 6b disposed above the press machine (for example, a hole diameter larger by about φ1 mm).
[0021]
Further, a horizontal support groove portion 9 for bolt positioning and setting that is continuous with a part of the female groove portion 4 is horizontally cut on the die surface of the die 1 so as to reach the die end. A half of the diameter of the shaft portion 2a of the bolt body 2 is placed in the horizontal support groove 9 to horizontally support the bolt body as a whole. Further, a taper surface 15 for preventing misalignment is provided at the lower end edge of the male round punch 8 installed above the axis of the vertical punching hole 5 (see FIG. 3). The inclination angle β of the taper surface 15 for preventing misalignment is preferably about 50 °, for example.
[0022]
Reference numeral 10 denotes a guide mold having an appropriate thickness, which is placed on the upper surface of the mold 1. The guide mold 10 is opened at the front end at one side facing the position directly above the lower female mold groove 4. The head guide cutout recess 11 is provided, and a punch through hole 12 is provided at the upper center of the guide mold 10. The above-described overall configuration provides an eyebolt cold drilling device.
[0023]
Now, this function will be described. A bolt 13 is applied to the shaft portion 2a in a separate process, and a bolt body 2 which is an intermediate molded member in which a tip portion serving as a head is formed on the flat spherical head 3 is used to form an eyebolt. As a drilling operation, first, the mold 1 having the curved female groove portion 4 is fixed to a table portion 6a of a predetermined press machine 6 that performs cold punching by a known means. In the illustration of FIG. 6, the table portion 6 a is tightened by a locking claw 16 that is a bolt tightening mechanism.
[0024]
Here, a flat spherical head 3 formed at the tip of the bolt main body 2 in a curved female groove 4 provided on the upper surface of the mold 1 is placed in front of the press machine and overlapped with the mold 1. Inserted into the back of the notch recess 11 for guiding the head that opens on the front side of the guide mold 10, the flat spherical head 3 is placed in the female groove 4 of the mold 1, and the flat portions 3 a, 3 a on both sides are directed vertically. When the shaft portion 2a of the bolt body 2 is guided to the horizontal support groove portion 9 serving as a positioning and setting groove, the lower half of the bolt shaft portion 2a is fitted into the horizontal support groove portion 9, and the female groove portion 4, the lower half of the flat spherical head 3 is loosely fitted, and the bolt body 2 is supported horizontally as a whole. At this time, however, oil is appropriately applied to the flat spherical head 3 that receives the pressing pressure of the bolt body 2 in order to improve lubricity (not shown).
[0025]
Thereafter, as a punching operation of the hole, the punch 8 of the cemented carbide steel member, which is a male mold protruding from the punch plate 6b on the upper side of the press machine 6, is lowered by an appropriate operation, and the punch 8 is moved to the guide mold. The flat spherical head 3 is once crushed by the press pressure and formed into the gap a between the female groove portion 4 by pressing down the central portion of the flat spherical head 3 set immediately below through the 10 punch through holes 12. Plastic deformation that instantaneously expands to a full gap (for example, a gap of about 0.3 mm) is made, and punching action of the punch 8 is performed due to this expansion, so that a hole is made with a relatively small punch pressure. When the flat spherical head 3 reaches a certain width (forming gap a), the curved female groove 4 acts as a wall to suppress swelling, and a kind of bulging position is restricted, and no member displacement occurs, so that stable punching is achieved. The hole 14 having a predetermined diameter can be easily formed into the bright eyebolt 2 '.
[0026]
In this case, since the vertical punch hole 5 disposed at the center position of the female groove portion 4 has a downward pressure relief inclined punch surface 7 at the lip 5a thereof, the flat spherical head is formed by the inclined punch surface 7. Unnecessary extraction pressure (impact) applied to the portion 3 is relieved. This means that a buffering action that does not cause cracks or cracks in the mouth edge of the vertical punch hole 5 itself works, and the mold is kept good.
[0027]
Further, since there is a misalignment taper 15 (for example, an inclination of 50 °) around the lower end edge of the male punch 8, the descending punch 8 contacts the flat spherical head 3. There is no deviation when touching, and a positive hole can be made at the center position. In this way, the shape of the female groove portion 4 exhibits a slightly larger curved groove structure that allows the flat spherical head 3 to be crushed when pressed, and the flat spherical head 3 is punched out by plastic deformation. A hole 14 having a predetermined diameter is formed by the punch 8 without applying a pressing pressure. As shown in FIG. 5A, the shape of the flat spherical head 3 is the same as that of the thick flat spherical head 3 with both sides flattened to the same size as the diameter of the bolt body 2, or (B) of FIG. As shown in FIG. 5B, a deformed flat spherical head 3 in which only one side is flat and the opposite side is spherical may be used, or a spherical head 3 ′ having both sides arced as shown in FIG. Become. At this time, the shape of the female groove portion 4 naturally exhibits a deformed receiving groove (not shown).
[0028]
That is, as in another embodiment shown in FIG. 5C, punching can be performed even with a very thick head structure in which the head shape is a spherical head 3 '. Of the spherical head 3 ′ having the arc surfaces 3 b and 3 b as both surfaces, the arc surface 3 b on one half of the spherical head 3 ′ is set as a horizontal support that fits into the female groove portion 4 in the same manner as described above. If a punch 8 is lowered from above the arcuate surface 3b projecting into the upper half of the female groove portion 4, the spherical head 3 'as a whole has a large curved female shape with the bulging expected in advance as described above. The groove portion 4 is crushed and expanded to the full extent, the outer periphery is restricted, and a predetermined eye hole is punched out.
[0029]
Incidentally, if the relationship between the thickness dimension (cross section) D ′ of a suitable spherical head or flat spherical head D ′ and the diameter dimension D of the bolt body in a given bolt body is shown, The range of 2 / 3D to 3 / 2D is preferable (see FIG. 8C). For example, the diameter dimension D of the bolt body of the SWCH material is D = 12 mm, and the thickness dimension (cross section) D ′ of the spherical head or the flat spherical head is preferably D = 8 to 18 mm. According to the experiment, when the value of D ′ is not less than the above range, the shear resistance becomes large, and it is difficult to perform punching by cold forming using a punch under a certain condition. However, it is poor and the product value is lowered.
[0030]
In general, the shaft diameter D of the bolt body is designed to be approximately the same dimension of 12 to 14 mm, while the hole diameter φ provided in the spherical head or the flat spherical head is D = 12 mm. When a conventional die is used to punch a flat spherical head of a bolt body by punching a round punch with a hole diameter of φ = 12 mm, the plate thickness D ′ of the flat spherical head is considered in view of safety. Is less than 2/3 of the hole diameter size φ and needs to be less than 8 mm.
On the other hand, if the cold drilling apparatus according to the present invention is used, even if a hole with a hole diameter of φ = 12 mm is punched by punching a flat spherical head of the bolt main body, The plate thickness D ′ of the spherical head can be set to 2/3 or more of the hole diameter dimension φ, that is, 8 mm or more. The maximum value of the plate thickness D ′ of the flat spherical head is limited to 3/2 times the hole diameter dimension φ.
[0031]
【The invention's effect】
As described above, the cold drilling device for cold-formed eyebolts according to the present invention is slightly larger to allow the table-side mold to see the bulging portion where the spherical head or flat spherical head of the bolt body to be fitted is crushed by the punch pressure. Therefore, the spherical head or the flat spherical head can be swelled up to the full mold by punch pressure, so that punching can be performed even with a small press pressure.
[0034]
This is a punching process using a conventional press machine, and the relationship between the plate thickness of the spherical head or the flat spherical head and the hole is said to be limited to a plate thickness of less than 2/3 of the hole diameter. However, in a slightly larger female groove portion that allows for the bulging and bulging of the member, it is possible to drill holes with dimensions that are the same as or larger than the bolt body diameter dimension or a slightly smaller approximate dimension. For this reason, even if the spherical head or the flat spherical head has a slightly thick structure, a desired hole can be formed, and as a finished eyebolt, the eye hole part (drilled part) is increased in thickness and withstands strength. Product value will also increase.
[0035]
In addition, since the lip of the punch hole at the center of the female groove portion of the die is provided with an inclined punching surface for press pressure relief, the press impact is buffered and the hole lip is not cracked or damaged. Keep better. For example, a mere punched-out edge has a chipped edge with a punching frequency of about 1 to 30,000 times, but a lip with a sloped punching surface according to the present invention does not cause cracks or breakage even with a number of punched times of 200,000 or more. .
[0036]
In addition, since a taper surface for preventing misalignment is provided around the bottom edge of the punch, which is a male mold, there is no misalignment (deviation) when descending against the member to be removed (flat spherical head, etc.), and the center position is surely perforated. It becomes. In addition, since a horizontal support groove that makes it easy to set bolts is attached to the upper surface of the mold, it is easy to set the bolt body to the mold, making it possible to drill 6000 to 7000 holes per day. Play.
[Brief description of the drawings]
FIG. 1 is a front view showing a main part of one embodiment of a cold-formed eyebolt according to the present invention.
FIG. 2 is an explanatory view showing an embodiment of a cold drilling device for forming the cold-formed eyebolt.
FIG. 3 is an explanatory view showing a main part of the punch portion.
FIG. 4 is an explanatory view showing a main part of the mold.
5A is a perspective view of a bolt main body having a hole formed in a flat spherical head, and FIG. 5B is a perspective view of the bolt main body before the drilling; FIG. It is a perspective view, (C) is a perspective view before drilling of another embodiment in which the bolt body head is a spherical head.
FIG. 6 is an explanatory diagram in which a die is provided in a table portion of a press machine and punches are arranged in a punch plate portion.
FIG. 7 is a perspective view of a mold.
FIG. 8 is an explanation of punching the eye hole by cold forming at the tip head of the bolt body. FIG. 8A shows that the head thickness for making the eye hole in the conventional bolt body is set smaller than the diameter of the bolt body to facilitate punching. It is explanatory drawing, (B) is explanatory drawing of the other Example which set the same head smaller than the bolt main body diameter, (C) is the bolt main body of this invention, and head thickness is more than the bolt main body diameter. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Mold 1a Receiving groove 2 Bolt main body 3 Flat spherical head 3 'Spherical head 4 Female die groove part 5 Vertical punching hole 5a Mouth edge 7 Inclined punching surface for pressure relief 8 Punch 9 Horizontal support groove part 14 Hole 15 Taper for slippage prevention surface

Claims (1)

In a cold drilling apparatus that drills a hole of a predetermined diameter in a spherical head or a flat spherical head of the bolt body, a table side mold that receives half of the spherical head or the flat spherical head of the bolt main body, The flat spherical head is crushed by punch pressure and is formed in a slightly larger female groove that allows the bulging part to swell to the outer periphery. A horizontal support groove for receiving the shaft portion of the bolt body is provided at one end of the female groove, and the male die disposed above the vertical hole is axially stopped at the lower edge. A cold drilling device for cold-formed eyebolts, characterized in that it is provided with a punch provided with a taper surface for use.

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