Patent Application
20050227846
The present invention concerns mechanical devices, more particularly to mechanical devices for stripping waste from a pre-cut sheet of material.
Presses for cutting sheet material such as paper, paperboard, cardboard and the like, are well known. When the sheet material is pre-cut and includes pre-cut portions, which need to be stripped out, the presses include stripping stations. One such stripping station is disclosed in U.S. Pat. No. 3,786,731, issued to Bobst et al. on Jan. 22, 1974 for “Press for Cutting Sheet Material”. Bobst discloses stripping stations, which include a pair of frames and a board, which has a series of pre-cut die openings, which are shaped to the desired design. Stripping tools are mounted to the frames and sandwich the waste material between once the sheet material is moved horizontally between the two frames. The stripping tools work together to remove the waste material. One problem, however, the stripping stations may operate too slowly for use with a high throughput stripping. Moreover, paper jams may occur frequently once the waste piece has been removed, thus causing the stripping station to be shut down for a significant time while the jam is removed.
Thus there is a need for an improved stripping device.
The present invention reduces the difficulties and disadvantages of the aforesaid designs by providing a resilient spring-like stripping device, which can be easily retrofitted into an existing pressing machine to strip waste portions from a pre-cut sheet, without the need for complex machinery. The stripping device is constructed from inexpensive materials such as stainless steel. Advantageously, the previously mentioned problems associated with paper jams is significantly reduced or essentially eliminated by the addition of a blocking member, which prevents the waste pieces from interfering with a stripping operation. The inherent resilience of the stripping device enables significantly increased stripping speeds, which increases productivity and decreases stoppage time. Furthermore, the device of the present invention significantly reduces pre-press/on-press make ready times.
In accordance with a first embodiment of the present invention, there is provided a stripping device for stripping a waste piece from a sheet of material, the device comprising: a) a stripping member having a connecting portion, a supporting finger located on one side of the connecting portion, and a stripping finger located on another side of the connecting portion; b) the supporting finger having a first end connected to a frame, the supporting finger being movable about the first end with respect to the frame; c) the stripping finger having a stripping end portion, the stripping end portion being biased away from the supporting finger for contacting at an angle the waste piece to be stripped, the supporting finger being deflectable away from the waste piece, the stripping end portion being movable further away from the supporting finger and against the waste piece so as to strip the waste piece.
In accordance with another aspect of the present invention, there is provided a stripping device for use in a die cutting press, for stripping a waste piece from a pre-cut sheet, the press having a first frame having at least one frame opening therein and a second frame having at least one punch complementary with the frame opening, the frames being movable with respect to each other, the punch being cooperable with the frame opening, the device comprising: a) a folded over piece of resilient material having a supporting finger located on one side of the fold, and a stripping finger located on another side of the fold, the supporting finger having a first end connected to the first frame, the supporting finger being movable about the first end with respect to the first frame, the stripping finger having a stripping end portion, the stripping end portion being resiliently biased away from the supporting finger for contacting at an angle the waste piece to be stripped, the supporting finger being deflectable away from the waste piece, the stripping end portion being movable further away from the supporting finger and against the waste piece so as to strip the waste piece; b) a blocking member for blocking the waste piece after it has been stripped, the blocking member having a second end resiliently hinged to the frame and a pair of blocking fingers connected to the second end, the blocking fingers being spaced apart to define a gap therebetween, the gap being of sufficient size to permit the stripping end portion to move between the blocking fingers.
In accordance with yet another aspect of the present invention, there is provided a method of stripping a waste piece from a sheet of pre-cut material, the method comprising: a) biasing a stripping finger away from a supporting finger, the stripping finger being in contact with the waste piece at an angle; b) deflecting the supporting finger away from the waste piece so as to strip the waste piece from the sheet.
Further aspects and advantages of the present invention will become better understood with reference to the description in association with the following Figures, in which:
a is a perspective view of the stripping frames showing the stripping device connected to a lower stripping frame;
b is a bottom view of the stripping device and a sheet of pre-cut material;
a is an exploded perspective view of an alternative blocking member;
b is an exploded perspective view of another alternative blocking member;
c is an exploded perspective view of another alternative blocking member;
a is a simplified side view of the stripping device in a default position;
b is a simplified side view of the stripping device in an intermediate stripping position;
c is a simplified side view of the stripping device in a final stripping position showing a waste piece being removed from the pre-cut sheet; and
d is a simplified side view of the stripping device showing the stripped waste piece contacting the blocking member.
Referring now to
Referring now to
As best seen in
As best seen in
In the embodiment illustrated, the intermediate portion 46 tapers away from the distal portion 42 towards the proximal portion 44, so that the proximal portion 44 is narrower than the distal portion 42. The proximal portion 44 is an elongate rectangular strip with the stripping end portion 40 located at a squared end 48 of the rectangular strip. The squared end 48 is typically sharp to enable it to dig into the waste piece 12 and to strip it from the pre-cut sheet 14. The stripping finger 36 is resiliently hinged to the arcuate connecting portion 32 to permit movement of the stripping end portion 40 relative to the supporting finger 34 between default and stripping positions. The connection between the stripping finger 36 and the arcuate connecting portion 32, because of the inherent resilience of the folded over stainless steel, operates as a first resilient hinge 50 to permit the stripping finger 36 to move relative to the supporting finger in a restricted hinging movement. The body opening 24 has an opening axis 52 and the first resilient hinge 50 has a first hinge axis 54, which is generally perpendicular to the opening axis 52.
The length of the stripping finger 36 is typically longer than the length of the supporting finger 34 so that the stripping end portion 40 is disposed below the first end 38 and into the body opening 24.
The supporting finger 34 has a distal portion 56, a proximal portion 58 and an intermediate portion 60. The distal portion 56 connects the supporting finger 34 to the arcuate portion 32, the proximal portion 58 connects the first end 38 of the supporting finger 34 to the intermediate portion 60 and the intermediate portion 60 interconnects the distal portion 56 and the proximal portion 58. The distal portion 56 and the proximal portion 58 may be tapered towards the intermediate portion 60. The intermediate portion 60 may be narrower than the distal and proximal portions. A connecting foot 62 is located at proximal portion 58 and connects the supporting finger 34 to the frame 18. The connecting foot 62 is disposed away from the body opening 24. To permit the supporting finger 34 to be deflected rearwardly away from the body opening 24, the supporting finger 34 is resiliently hinged to the frame 18 so that the supporting finger can move relative to the frame 18 between default and stripping positions. A second resilient hinge 64 is located near the connecting foot 62 and has a second hinge axis 66, which is perpendicular to the opening axis 52. The second hinge axis 66 and the first hinge axis 54 are generally parallel to each other and perpendicular to the opening axis 52.
The blocking member 30 includes a second end 68 connected to the frame 18 and a blocking portion 70. In the default configuration, the stripping finger 36 is located adjacent the blocking portion 70. The second end 68 of the blocking member 30 is located adjacent the body opening 24 so that the blocking portion 70 is disposed towards and into the body opening 24, and inclined away from the second end 68. The blocking portion 70 has a pair of blocking fingers 72, which are connected to the second end 68. The blocking fingers 72 are spaced apart and define a gap 74 therebetween. The gap 74 is of a sufficient size to permit the rectangular strip of the stripping finger 36 to move between the blocking fingers 72. Each blocking finger 72 has a proximal blocking panel 76, which contacts the waste piece 12. A blocking finger distal portion 78 resiliently and hingeably connects the blocking finger 72 to the second end 68 and an intermediate portion 80 interconnects the proximal blocking panel 76 with the distal portion 78. A third resilient hinge 79 is located between the distal portion 78 and the second end 68 to allow the blocking member 30 to move when the stripping member 28 moves during the stripping operation. The third hinge 79 has a third hinge axis 81, which is generally parallel to the first and second hinge axes 54, 66. The proximal blocking panel 76 is disposed perpendicular to the intermediate portion 80 and generally parallel to the opening axis 52. The rectangular strip of the stripping finger 36 is disposed rearwardly of the blocking fingers 72 in the default position. The blocking member 30 is typically made from a single piece of resilient stainless steel. It is also contemplated that the stripping member 28 and the blocking member 30 may be made from a single piece of resilient material, without deviating from the scope of the present invention. Moreover, in another aspect, the blocking member 30 may also be made from a piece of resilient plastic.
In the embodiment illustrated, the second end 68 of the blocking member 30 and the first end 38 of the stripping member 28 are connected together, typically using conventional securing means. It is also contemplated that the stripping member 28 and the blocking member 30 may be used together or they may be used separately.
Operation
A typical stripping operation will now be described with reference to
The stripping device 26 may begin from the default configuration, as shown in
Alternatives
The embodiment of the stripping device 26 described above may also be used with different designs of blocking member 30, as illustrated in
An alternative blocking member 100, as seen in
Another alternative blocking member 104, as seen in
Still another alternative blocking member 106 includes a pair of blocking wires 108 connected to the second end 68. The alternative blocking members 100, 104 and 106 operate essentially identically to the blocking member 30.
While specific embodiments have been described, those skilled in the art will recognize many alterations that could be made within the spirit of the invention, which is defined solely according to the following claims.
