JPS646993Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a mandrel used for bending a shape having a cylindrical hollow part used for balconies, entrance doors, decorative windows, handrails, carports, etc.

Conventionally, in order to bend a section having a cylindrical hollow part, a bending die 1 is used as shown in FIG.
The bending process is carried out using a mandrel 4 by a draw-bending machine equipped with a fixed clamp die 2 and a movable clamp die 3 fixed to the bending die 1.

The mandrel 4 has a cross-sectional shape that matches the inner shape of the cross section of the hollow section of the section 5 having a cylindrical hollow section, and the outer surface of the tip has a curved surface 4a curved to the same curvature as the bending curvature. What has been done is known.

However, with a mandrel shaped like this,
When the section 5 is bent, the inner wall 5 of the section 5
a, that is, the inner wall 5a in the bending direction is separated from the inner surface 4b of the mandrel 4 near the bending start point A, so that wrinkles, dents, etc. occur in the inner wall 5a.

For this reason, when it is used as a cap for a balcony or the like, it looks undesirable, and it also has the disadvantage that gas accumulates in the wrinkles and depressions during alumite treatment, making it impossible to perform the alumite treatment sufficiently.

Normally, wrinkles and dents are corrected and finished by hand, but it is actually a difficult task to correct wrinkles and dents to make them completely flat, and the processing cost increases accordingly. It gets expensive.

In addition, the curved surface 4a of the mandrel 4 must match the bending curvature of the profile 5, and when bending to a different curvature, the curved surface 4a that matches the curvature
requires another mandrel with a, and the number of mandrels becomes very large.

The present invention was developed in view of the above circumstances, and its purpose is to press the inner wall of the shape material in the bending direction when bending a shape material having a cylindrical hollow part, and to bend the material near the bending start point. To provide a mandrel for bending a shaped material having a cylindrical hollow part, which can reliably prevent the occurrence of wrinkles, dents, etc., and can also be used when bending with different curvatures.

Embodiments of the present invention will be described below with reference to FIG. 2 and subsequent figures.

FIG. 2 is an explanatory diagram showing an example of a bending machine, and the bending die 10 that is rotatably driven includes
A fixed clamp die 11 and a movable clamp die 12 are provided, and each die 10, 11, 12 is rotated as one unit.

13 is a wiper die, 14 is a pusher die, which is fixed at the start of bending and movable clamp die 1.
1 and 12 on the fixed side, and
5 guide and a function to apply back tension during bending.

The section 15 is, for example, a long member having a cylindrical hollow part 15' as shown in FIG. 3, and in FIG. It is inserted between the pusher die 14 from the direction of arrow A.

16 is a mandrel, which includes a base 17 and a main body 1.
8, the base 17 is connected to the piston rod 20 of the cylinder 19, and by moving the piston rod 20 forward and backward, it can be inserted into the bending position in the cylindrical hollow part 15' of the section 15, and can be bent. or extract it from the section.

The main body portion 18 is made of abrasion resistant material such as synthetic resin material,
A plurality of first plate-shaped elements 21 made of a material with excellent lubricity and elasticity and second plate-shaped elements 22 made of a metal with high spring properties such as a plate spring are alternately arranged in the bending direction of the profile 15. The cross section in the stacked state is the shape 15.
The first plate-like element 21 is located on both sides, substantially matching the inner shape of the cross-section of the hollow part, and a plurality of grooves are provided at appropriate intervals in the longitudinal direction on the opposing surface of the first plate-like element 21. 23 is formed, and the base of each plate-like element 21, 22 is connected to the base 17.
It is fitted into the recess 17a and firmly connected with bolts 24 and knock pins 25.

In addition, in the embodiment, every other second plate-like element 22 is adjacent to the first plate-like element 2.
1 and 21, and a groove 23 is formed only on the opposing surface in contact with the second plate element 22, and the length of each plate element 21, 22 is equal to that of the inner plate element in the bending direction. The plate-like elements are gradually longer toward the outer side.

Next, the bending operation of the section 15 will be explained.

Movable clamp die 12 and pusher die 14
is moved to the left in the figure to be separated from the fixed clamp die 11 and wiper die 13, and the piston rod 20 of the cylinder 19 is moved forward to move the mandrel 16 until its main body 18 is located near the bending start point A. let

In this state, the profile 15 is inserted in the direction of arrow A, and the mandrel 16 is placed inside and abuts against the stopper 26, so that the mandrel 16 is inserted into the hollow portion 15' of the profile 15.

The movable clamp die 12 presses and holds the profile 15 against the fixed clamp die 11, and the pusher die 14 presses the profile 15 against the wiper die 13 to guide the sliding of the profile 15. Provides back-tension during bending.

In this state, the bending die 10 and the clamp dies 11 and 12 are integrally rotated in the direction of arrow B, and the profile 15 is bent along the bending die 10.

At this time, the main body 18 of the mandrel 16 bends and deforms along the bending radius of the bending die 10, but the bending stress due to the bending direction outer wall 15a of the profile 15 is applied from the outer first plate element 21' to the innermost side. This is transmitted to the first plate-like element 21'', and each plate-like element 21, 22 curves smoothly following the bending of the section 15 while sliding relatively in the longitudinal direction, and the innermost first plate-like element 21'' curves smoothly along the bending direction inner wall 15b of the profile 15, and strongly presses the inner wall 15b along the curved surface of the bending die 10, thereby forming the bending starting point A.
There is no room (gap) for wrinkles, dents, etc. to occur in the inner wall 15b of the profile 15 in the vicinity, and the profile 15 can be drawn and bent into a predetermined shape in a single forming process without wrinkles, dents, etc. , the same mandrel can be used for bending with different curvatures.

Furthermore, since the first plate-like element 21 is in contact with the outer walls 15a and 15b of the profile 15, the first plate-like element 21 and the inner and outer walls 15a and 15b are in contact with each other.
Since the sliding resistance with 5a and 15b does not become extremely large, the profile 15 can be easily pulled and moved with an appropriate tensile force.

Furthermore, since the second plate element 22 is a metal plate with high spring properties, when the profile 15 is pulled out from the mandrel 16 after the bending process is completed, the mandrel 16 is straightened by the restoring force of the second plate element 22. Immediately restore the state to
5 can be inserted smoothly, and the shape 15
It becomes easy to set.

Further, since the groove 23 is formed on the opposing surface of the first plate element 21 that is in contact with the second plate element 22, the first and second plate elements 21, 2
2 is reduced, the first and second plate elements 21 and 22 can smoothly rub their sliding surfaces in the longitudinal direction, and the main body 18 can be bent smoothly with a small force.

As shown in FIG. 6, among the plate elements 21 and 22 constituting the main body 18 of the mandrel 16, the inner first plate element 21'' is the longest, and the outer first plate element 21' is the longest. Alternatively, as shown in FIG. 7, the plate elements 21 and 22 may have the same length, and the second plate elements 22 may be arranged between adjacent first plate elements 21. It is also possible to intervene.

Since the mandrel according to the present invention has the above-described structure and function, when bending the profile along the bending radius of the bending die, the bending stress due to the outer wall in the bending direction of the profile is applied to the outer plate shape. It is transmitted from the element to the innermost plate-like element, and each plate-like element follows the bending of the shape material with appropriate rubbing movement on the laminated surface in the longitudinal direction and curves smoothly. , the inner wall in the bending direction of the profile is strongly pressed along the curved surface of the bending die, and there is no room for wrinkles, dents, etc. to occur on the inner wall near the bending start point; In addition, a predetermined bending process of a profile can be performed by a single forming process, and the same mandrel can be used even when bending process to different curvatures.

In addition, a first
Since the plate elements 21 are stacked so as to be in contact with each other, the first plate elements 21 are located on both sides of the section 15 in the bending direction, and the first plate elements 21 are in contact with the inner and outer walls 15a and 15b of the section 15. Since the first plate-like element 21 is the first plate-like element 21, the sliding resistance between the first plate-like element 21 and the inner and outer walls 15a, 15b of the shape member 15 does not become extremely large.
can be easily pulled and moved with an appropriate pulling force.

In addition, since the second plate element 22 is a metal plate with high spring properties, when the profile 15 is pulled out from the mandrel 16 after the bending process is completed,
The mandrel 16 is immediately restored to its straight state by the restoring force of the second plate-like element 22, and then the section 15 can be inserted smoothly, making it easy to set the section 15.

Furthermore, since the groove 23 is formed on the surface of the first plate element 21 that contacts the second plate element 22, the contact area between the first and second plate elements 21 and 22 is reduced, and the first・Second plate element 2
Nos. 1 and 22 allow smooth sliding movement of the sliding surface in the longitudinal direction, and the mandrel can be smoothly bent with a small force.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of a conventional example, Fig. 2 and subsequent figures show examples of the present invention, Fig. 2 is a schematic plan view of a bending device using the mandrel of the present invention, and Fig. 3 is a perspective view of a profile. Figure 4 is a perspective view of the mandrel of the present invention, Figure 5 is an explanatory view showing the working state of the mandrel during bending, and Figures 6 and 7 are front views showing other embodiments of the mandrel. be. 10 is a bending die, and 21 and 22 are plate-like elements.

Claims (1)

[Scope of utility model registration request] This is a mandrel that is positioned inside the cylindrical hollow part 15' of the cylindrical hollow part 15' when the cylindrical hollow part 15' is bent along the bending die 10, and has wear resistance, lubricity, and a plurality of first plate elements 21 made of a material with excellent elasticity.
and a plurality of second plate elements 22 made of metal with high spring properties.
are stacked in the bending direction of the section 15 so that the first plate elements 21 are in contact with both sides of the section, and the cross section approximately matches the inner shape of the cross section of the cylindrical hollow portion 15' of the section 15; Connecting one end in the longitudinal direction of each of the first and second plate elements 21 and 22,
The mandrel for bending a shaped material having a cylindrical hollow portion is further characterized in that a groove 23 is formed on a surface of each of the first plate elements 21 that is in contact with the second plate elements 22.