1. Field of the Invention
This invention relates to a punching device, more particular to a punching device including a pair of driving levers for driving a punch to slide against a die for cutting a sheet.
2. Description of the Related Art
Referring to
Referring to
Although the pressing lever 25 of the punching device 200 permits a less force required to punch the sheet as compared to the previous conventional punching device 100, it undesirably and considerably increases the length of the punching device 200 attributed to the length of the pressing lever 25. Moreover, according to the lever principle, the shorter the distance between the pivot end 251 (fulcrum) and the driving protrusion 252 (load) and the longer the distance between the pivot end 251 and the pressing end 253 (effort), the more will be the mechanical advantage, i.e., the less effort is required. Since the contact between the driving protrusion 252 and the punch 22 is required to be located on the vertical axis (Y) in order to prevent imbalance problem for the punch 22 (inclination of the punch 22 or uneven movement of the punch 22) from occurring, the distance between the pivot end 251 and the driving protrusion 252 is fixed and cannot be reduced. As a consequence, the longer the distance between the pivot end 251 and the driving protrusion 252, the longer the distance between the pivot end 251 and the pressing end 253 is required to maintain the same effort. In addition, since the pressing end 253 of the pressing lever 25 is located at one side of the punch device 200 and is relatively far from the vertical axis (Y), the dimensions of the base 21 are required to be enlarged in order to increase the stability of the punch device 200 and to prevent the punch device 200 from raising up or flipping over upon pressing of the pressing end 253, thereby further increasing the overall size of the punch device 200.
Therefore, an object of the present invention is to provide a punching device that can easily punch a sheet without increasing the size of the punching device as encountered in the prior art.
According to the present invention, there is provided a punching device for cutting a sheet. The punching device comprises: a housing defining an inner housing space and having a surrounding frame part, an upper part and a flange part, the surrounding frame part having upper and lower end portions, the upper part being movably supported on the upper end portion of the surrounding frame part and having an abutting protrusion, the flange part extending transversely from the lower end portion of the surrounding frame part, being formed with a lower spring-holding member, and defining a flange hole; two opposite pivot seats protruding upwardly from the flange part into the inner housing space and opposite to each other in a first direction; a die part disposed below and operatively connected to the flange part; a punch unit including a punch head, an upper spring-holding member, and a punch, the upper spring-holding member protruding upwardly from the punch head, the punch being disposed between the pivot seats and extending downwardly from the punch head toward the die part; a spring extending between and abutting against the upper and lower spring-holding members, so that the punch unit can be supported movably on the flange part and that the punch is slidable through the flange hole and against the die part along a vertical axis substantially perpendicular to the first direction; and a pressing unit including two driving levers, each of which has a pivot end that is pivoted to a respective one of the pivot seats, a pressing end that is opposite to the pivot end, a first end segment that extends along a first line of its length direction from the pivot end, a second end segment that extends along a second line of its length direction from the pressing end, a middle segment that interconnects and that deflects from the first and second end segments, and a driving protrusion disposed between the pivot end and the pressing end and protruding therefrom toward the punch unit. The middle segment has curved first and second end portions that turn curvedly and respectively from the first and second end segments. The first lines, along which the first end segments extend, intersect each other at the vertical axis. The second lines, along which the second end segments extend, are substantially parallel to each other and are spaced apart from the vertical axis. The vertical axis is disposed between the driving protrusions of the driving levers. The driving protrusions of the driving levers are disposed in a symmetrical manner with respect to the vertical axis, and press against the punch unit to drive movement of the punch unit along the vertical axis toward the die part for cutting the sheet. The upper part is disposed on and abuts against the pressing ends of the driving levers, and is movable relative to the surrounding frame part along the vertical axis for pressing the driving levers to rotate relative to the surrounding frame part. The driving levers are rotatable relative to the surrounding frame part about first and second rotational axes, respectively, between an initial position and a cutting position. The first and second rotational axes are transverse to the first direction and the vertical axis. When the driving levers are disposed at the initial position, the abutting protrusion of the upper part is pushed by the pressing ends of the driving levers to abut against the upper end portion of the surrounding frame part by the urging action of the spring and in the meantime the driving levers extend upwardly and respectively from the pivot ends to the pressing ends and cross each other. When the driving levers are disposed at the cutting position, the abutting protrusion of the upper part is spaced apart from the upper end portion of the surrounding frame part.
In drawings which illustrate embodiments of the invention,
Before the present invention is described in greater detail with reference to the accompanying preferred embodiments, it should be noted herein that like elements are denoted by the same reference numerals throughout the disclosure.
Referring to
The pivot ends 411 of the driving levers 41 are respectively pivoted to the C-shaped hooks of the pivot seats 332 so that the driving levers 41 are rotatable relative to the flange part 33 about first and second rotational axes (X1, X2), respectively, between an initial position (
The driving protrusions 413 of the driving levers 41 are disposed respectively at two sides of the vertical axis (Z) in a symmetrical manner with respect to the vertical axis (Z), and press against the punch unit 5 for driving movement of the punch unit 5 along the vertical axis (Z) toward the die part 2 for cutting the sheet.
The upper end portion 371 of the surrounding frame part 37 has a generally U-shaped cross-section, and defines an opening 3710 for extension of the upper part 36 therethrough.
The upper part 36 is disposed on and has a bottom end face that abuts constantly against the pressing ends 412 of the driving levers 41. The upper part 36 is movable relative to the surrounding frame part 37 along the vertical axis (Z) for pressing the driving levers 41 to rotate relative to the flange part 33 and the surrounding frame part 37.
The flange part 33 is generally rectangular in shape, has four corners, and is disposed directly above the die part 32. The pivot seats 332 are disposed at two diagonally aligned ones of the corners, respectively. The die part 32 has a die hole 319 for extension of the punch 52 therethrough. In this embodiment, the die part 32 is magnetically attached to the flange part 33 through a magnetic unit so as to be operatively connected to the surrounding frame part 37 through the flange part 33. The magnetic unit includes a plurality of magnets 61 which are secured to the die part 32 and the flange part 33, so that the sheet of paper can be placed on the die part 32 for punching before the die part 32 is magnetically attached to the flange part 33 to sandwich the sheet of paper therebetween.
Referring to
When the driving levers 41 are disposed at the initial position, the abutting protrusion 361 of the upper part 36 is pushed by the pressing ends 412 of the driving levers 41 to abut against the upper end portion 371 of the surrounding frame part 37 by the urging action of the springs 431 and in the meantime the driving levers 41 extend upwardly and respectively from the pivot ends 411 to the pressing ends 412 and cross each other in such a manner that the second end segments 416 extend upwardly and respectively from the middle segments 417 in a direction inclined to the first direction (T) and that the second end portions 4172 of the middle segments 417 overlap each other in a second direction (Y), which is perpendicular to the vertical axis (Z) and the first direction (T). When the driving levers 41 are disposed at the cutting position, the abutting protrusion 361 of the upper part 36 is spaced apart from the upper end portion 271 of the surrounding frame part 37 and in the meantime the second end segment 416 of one of the driving levers 41 overlaps the first end segment 415 of the other one of the driving levers 51 in the second direction (Y) and the second end segment 416 of said the other one of the driving levers 41 overlaps the first end segment 415 of said one of the driving levers 51 in the second direction (Y). In addition, the second end portions 4172 of the middle segments 417 are misaligned with each other in the second direction (Y) when the driving levers 41 are disposed at the cutting position.
The diagonal relation of the relative position between the driving levers 41 and the configuration of the first and second end segments 415, 416 and the middle segment 417 permits achievement of a compact design of the punching device.
The extension of the driving levers 41 to cross each other results in an increase in the lever arm of force and permits the driving protrusions 413 to be positioned at positions closer to the vertical axis (Z), which has the advantage of preventing the punch 22 from becoming obliquely relative to the vertical axis (Z) due to unbalanced forces acting on the pressing ends 412 of the driving levers 41 during punching. In addition, the extension of the driving levers 41 to cross each other further permits the pressing ends 412 of the driving levers 41 to have sufficient heights relative to the flange part 33, which is advantageous in providing a sufficient traveling distance for the pressing ends 412 of the driving levers 41 during a punching operation.
With the invention thus explained, it is apparent that various modifications and variations can be made without departing from the spirit of the present invention.
Number | Date | Country | Kind |
---|---|---|---|
99204033 U | Mar 2010 | TW | national |
2010 2 0151904 U | Mar 2010 | CN | national |
This application is a Continuation-in-Part (CIP) of U.S. patent application Ser. No. 13/024,852 filed on Feb. 10, 2011, which claims priority to Taiwanese Patent Application No. 099204033, filed on Mar. 8, 2010, and Chinese Patent Application No. 201020151904.1, filed on Mar. 25, 2010, which are incorporated herein by reference in their entirety.
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Number | Date | Country | |
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20140165811 A1 | Jun 2014 | US |
Number | Date | Country | |
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Parent | 13024852 | Feb 2011 | US |
Child | 14148112 | US |