BACKGROUND OF THE INVENTION
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1. Field of the Invention
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The present invention relates to a spring forming machine and more specifically, to a bending device for spring forming machine, which has two push members obliquely movably supported on a respective holder member at a respective slide being vertically slidable mounted on a vertical rail at the right side of the machine frame for bending a metal strip to form a coiled spring.
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2. Description of the Related Art
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A conventional spring forming machine comprises a machine frame 100, a feeding device 10, a cutting device 20, a bending device 30, and a positioning cylinder 40 (see FIGS. 1 and 2). The cutting device 20 comprises a cutter 201 and a pitch control member 202 arranged at two sides relative to the positioning cylinder 40. The bending device 30 comprises an upper push member 301 and a lower push member 302. The upper push member 301 and the lower push member 302 each have a working element 303 at the respective front working side. A metal strip 50 is pushed by the feeding device 10 to extend between the positioning cylinder 40 and the bending device 20, thereby forming a turn around the positioning cylinder 40. The pitch control member 202 is adapted to define a predetermined pitch for a coiled spring to be formed. The upper push member 301 and lower push member 302 of the bending device 30 are adapted to define a predetermined a pitch diameter for a coiled spring to be formed. By means of moving the upper push member 301 and the lower push member 302 at different speeds, the metal strip 50 is bent to form a right-hand spring (see FIG. 1) or left-hand spring (see FIG. 2). After a coiled spring of a predetermined length has been formed, the cutter 201 of the cutting device 20 moves downward to cut off the coiled spring from the metal strip 50.
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The upper push member 301 and lower push member 302 of the bending device 30 are driven by a common power source (not shown) through a cam wheel 60 and links 70 (see FIG. 3). The upper push member 301 moves obliquely upwards while the lower push member 302 moves obliquely downwards. For forming coiled springs having a different pitch diameter, the angle and position of the upper push member 301 and the lower push member 302 as well as the related working elements 303 must be relatively adjusted, i.e., the moving paths of the upper push member 301 and the lower push member 302 must be adjusted. Because these adjustments are done by labor, it is difficult to control the precision.
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Further, because the linking members (such as the cam wheel 60 and the links 70) are mounted on the wall front of the machine frame 100, the machine frame 100 must have a certain width for mounting. The big-sized machine frame 100 has a high material cost, thereby lowering the market competitiveness of the spring forming machine.
SUMMARY OF THE INVENTION
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The present invention has been accomplished under the circumstances in view. It is one object of the present invention to provide a bending device for spring forming machine, which can be mounted on the right side of the machine frame so that the width of the machine frame can be greatly reduced. It is another object of the present invention to provide a bending device for spring forming machine, which allows easy control of the power sources by the settings of a control box, preventing human errors
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To achieve these and other objects of the present invention, the bending device is used in a spring forming machine for bending a metal strip into a coiled spring, comprising a rail vertically mounted on a machine frame, a lower slide mounted on the rail and vertically slidable along the rail, an upper slide mounted on the rail above the elevation of the lower slide and vertically slidable along the rail, an oblique lower holder fixedly mounted on the lower slide in an oblique position, an oblique upper holder fixedly mounted on the upper slide in an oblique position revered to the lower holder, a lower push member coupled to the oblique lower holder for bending a metal strip into a coiled spring, an upper push member coupled to the oblique upper holder for bending a metal strip into a coiled spring, and plurality of power sources controllable to move the lower slide and the upper slide respectively in vertical direction along the rail and to move the lower push member relative to the oblique lower holder and the upper push member relative to the oblique upper holder respectively.
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Further, the power sources are servomotors controlled by a control box of the spring forming machine. Further, the rail is mounted on the right side of the machine frame.
BRIEF DESCRIPTION OF THE DRAWINGS
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FIG. 1 is a schematic plain view of a spring forming machine set for the fabrication of right-hand springs according to the prior art.
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FIG. 2 is a schematic plain view of the prior art spring forming machine when set for the fabrication of left-hand springs.
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FIG. 3 is a schematic plain view of the prior art spring forming machine, illustrating the arrangement of the cam wheel and the links.
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FIG. 4 is an exploded view of a bending device for spring forming machine according to the present invention.
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FIG. 5 is an elevational assembly view of the bending device for spring forming machine according to the present invention.
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FIG. 6 is a side view of the bending device for spring forming machine according to the present invention.
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FIG. 7 is a schematic plain view of the present invention, showing the bending device installed in a spring forming machine.
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FIG. 8 is an enlarged view of a part of FIG. 7.
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FIG. 9 is a schematic plain view of the present invention, showing the bending device in operation (I).
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FIG. 10 is a schematic plain view of the present invention, showing the bending device in operation (II).
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
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Referring to FIGS. 4˜6, a bending device a of a spring forming machine in accordance with the present invention is shown comprising a rail 1, an upper push member 2, a lower push member 3, and multiple power sources 4.
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The rail 1 (see FIGS. 7 and 8) is mounted on the right side of the machine frame b in vertical. The machine frame b has a width relatively smaller than the conventional design (when compared to FIG. 3). An upper slide 11 and a lower slide 12 are mounted on the rail 1 and vertically movably along the vertical rail 1. An oblique upper holder 13 and an oblique lower holder 14 are respectively affixed to the upper slide 11 and the lower slide 12. The oblique upper holder 13 is held on the upper slide 11 in an upwardly rightwardly tilting position. The oblique lower holder 14 is held on the lower slide 12 in a downwardly rightwardly tilting position.
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The upper push member 2 and the lower push member 3 are respectively coupled to and respectively obliquely movable along the oblique upper holder 13 and the oblique lower holder 14, each having a working element 21 or 31 at the respective front working side for bending a metal strip into a coiled spring.
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The power sources 4 can be servomotors that are set and controlled by a control box (not shown) of the spring forming machine. The power sources 4 are adapted to move the upper slide 11, the lower slide 12, the upper push member 2, and the lower push member 3.
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By means of a parameter setting through the control box to control the operation time and speed of the power sources 4, the upper slide 11 and the lower slide 12 are controlled to move upwardly or downwardly along the rail 1 subject to the settings, and the upper push member 2 and the lower push member 3 are controlled to move along the oblique upper holder 13 and the oblique lower holder 14 respectively subject to the settings, therefore the working elements 21 and 31 are moved relatively subject to predetermined operating paths, i.e., the working elements 21 and 31 can be moved upwardly rightwards or downwardly rightwards at different speeds to bend a metal strip into a right-hand spring or left-hand spring. For forming coiled springs having a different pitch diameter, alter the parameter settings of the control box to change the operation time and speed of the upper slide 11, lower slide 12, upper push member 2, and lower push member 3. Therefore, the invention eliminates manual operation and assures high accuracy.
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Except the rail 1 on the machine frame a, it is not necessary to install linking means (cam wheel, link, etc.) for the upper push member 2 and the lower push member 3. Therefore, the machine frame b can be made relatively narrower than the prior art design. Actually, the width of the machine frame b in accordance with the present invention can be reduced by ¼ when compared to the prior art design, thereby saving much the material cost for the machine frame b.
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As indicated above, by means of installing the rail 1 in the machine frame a to support the upper slide 11 with the oblique upper holder 13 and the lower slide 12 with the oblique lower holder 14, the upper push member 2 and the lower push member 3 can be moved vertically up and down and obliquely reciprocated by the power sources 4 subject to predetermined settings through the control box. This design eliminates human control errors and greatly improves the precision and the yield rate.
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Although a particular embodiment of the invention has been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the invention.
