JPH0718443Y2 - Expander for forming square cans - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to an improvement of a square can molding expander used when molding a round can into a square can.

(Prior Art) No. 4 is the conventional expander system for forming square cans.
As shown in the figure, the upper and lower plates (1) are provided in parallel and separated from each other,
A structure in which the space (1 ') is expanded by the drive unit (5) to form a round can into a square can (7), and a shaft is provided in the block body (8) such as a quadrangle as shown in FIG. A cam rod (9) that moves in the direction is provided, and by operating the cam rod (9), push-out pieces (10) that can be freely taken in and out radially from the four corners of the block body (8) are arranged. Has been.

(Problems to be solved by the invention) In the expander using the driving device (5), when the upper and lower plates (1) and (1 ') are widened to form a round can into a square can (7), The corners of the upper and lower plates (1), (1 ') that come into contact with the four corners of the square can (7) strongly contact the can material (7). At this time, the sides of the can material (7) on the upper and lower plates (upper and lower sides) are easily compressed to cause wrinkles, and the sides of the can material (7) on the cylinder side (left and right sides) are stretched. Become thin. As a result, the mouth end portion after molding has a deformed shape as shown by the chain line in FIG.

Further, in the expander using the cam rod (9), when the push-out piece (10) is moved in and out, the cam portion keeps sliding, so that the wear is extremely severe. The state of formation of the square cans (7) changes depending on the degree of wear, and the dimensional accuracy is reduced, or the square cans (7) are molded into an irregular shape, and defective products are likely to occur.

When the square can (7) deformed as shown in FIGS. 4 and 5 is viewed three-dimensionally, the height (h) of the four sides of the square can (7) is the central portion as shown in FIG. Height (h1) becomes short [see FIG. 7 (a)]. This is molded into a flange-shaped mouth end as it is [see FIG. 7 (b)], and a lid (11) is attached and the flange is tightened [see FIG. 7 (c)]. Since the length (L) becomes shorter than the design dimension by the amount of deformation, there is a problem that it is easy to leak from there.

INDUSTRIAL APPLICABILITY The present invention is for forming a square can, in which an unreasonable force is not applied to the four corners of the can during molding of the square can, and the partial deformation of the can is almost eliminated to prevent leakage after the can is wound. It is in providing expanders.

(Means for Solving the Problems) In order to eliminate the above problems, according to the present invention, elastically biased pieces are swingably provided at respective corners of upper and lower plates corresponding to the four corners of a square can to be formed. It has a different structure.

(Operation) Next, the operation of the present invention will be described. A can material (7) formed by making a circular can close to a square shape is set around the product of the present invention [see FIG. 3 (a)]. Next, when the driving device (5) is actuated to extend the rod (5a), the space between the upper and lower plates (1) and (1 ') expands, and the contact portion (2) of the piece (2) is expanded.
a) contacts the can material (7). After that, the side of the can material (7) on the drive device side (left and right side) is stretched [see FIG. 4 (b)]. If the rod (5a) continues to extend thereafter, tensile force acts on the side of the can material (7) on the drive unit side and the pressing force of the contact portion (2a) becomes stronger. As the tensile force and the pressing force become stronger than the pressing force of the cushion member (4) that elastically biases the bridge body (2), the bridge body (2) gradually rotates, and the upper and lower plate sides (upper and lower plates) Square can (7) while moving the slack of the can material (7) on the side) to the driving device side and eliminating the tensile force on the upper and lower plates and the compression force on the driving device side.
Are formed on the substrate [see FIG. 3 (c)]. The can material (7) is formed at the same time when the rotation of the bridge body (2) is stopped and when the operation of the drive device (5) is stopped, so that the partial elongation is almost eliminated.

After that, the rod material (5a) of the drive device (5) is contracted to reduce the distance between the upper and lower plates (1), (1 '), and the can material (7) is removed [see Fig. 3 (d)]. ].

Embodiment An embodiment of the present invention will be described below with reference to the drawings.
(1) and (1 ') are substantially rectangular upper and lower plates provided in parallel and separated from each other, and the upper and lower plates (1) and (1') are provided at the central portions of the upper and lower plates (1) and (1 '). A drive device (5) described later for expanding the space of ′) is fixed. Further, step portions (1a) and (1a ') are provided at the respective corners of the upper and lower plates (1) and (1') corresponding to the four corners of the can material (7). (2) is a long swingable piece mounted on the upper side of each step (1a), (1a '), and the outside of the piece (2) is abutting with a rounded surface. A hinge portion (2b) is provided so as to project from the inside of the piece body (2). Reference numeral (3) is a hinge holder fixed to the upper side of each step (1a), (1a '), and the hinge holder (3) is pivotably supported on the piece (2). (4) is a cushion member which is provided on the lower side of each step (1a), (1a ') and elastically biases each piece (2). The cushion member (4) includes a plurality of springs (4a) and a block (4b) having a plurality of holes (4c) into which the springs (4a) are inserted at predetermined intervals. In addition to the above, the cushion member (4) is
For example, a plurality of pressing pieces for pressing the piece (2) and a cylinder type structure (not shown) in which the pressing pieces are operated by air or hydraulic pressure may be used. The strength of elastically urging each piece (2) is controlled by adjusting the number of springs (4a) or the set strength of air pressure and hydraulic pressure. (5) is a drive device such as a cylinder. (6) is a fastening member.

(Effects of the Invention) Since the present invention is configured as described above, the abutment portion (2a) of the piece body (2) can be molded while rotating without strongly hitting the can material (7). Almost no partial deformation of the material (7) occurs, and the mouth end has a shape as shown in FIG. Therefore, since the overlapped portion length (L) is wound to the length as designed, there is almost no risk of leakage.

[Brief description of drawings]

FIG. 1 is a front view showing an embodiment according to the present invention, FIG. 2 is an enlarged sectional view showing an essential part, and FIGS. 3 (a) to 3 (d) are explanatory views showing the action, FIGS. FIG. 7 is an explanatory view showing the structure of a conventional product, FIG. 6 is an explanatory view showing a can formed by the product of the present invention, and FIG.
(A)-(c) is explanatory drawing which shows the winding process of the can formed with the conventional product. (1), (1 ') …… Upper and lower plates (2) …… Body, (5) …… Driving device (7) …… Square can

Claims (1)

[Scope of utility model registration request] 1. Upper and lower plates (1) provided in parallel and separated from each other,
In the expander for forming a square can by expanding the space of (1 ') by a driving device (5) to form a square can into a square can (7), the upper and lower plates (1) corresponding to the four corners of the square can (7). ), (1 ') at each corner, an elastically biased piece body (2) is swingably provided, and a square can molding expander.