Slitter blade guard

Abstract

A retractable safety cover for a slitting blade edge. This cover pivots about an axis that is perpendicular to the axis of rotation of the blade edge. The cover is spring loaded in the open direction and is held in the covered orientation by a spring loaded moveable block. By retracting the moveable block the blade edge is exposed for use.

Claims

1. An apparatus for retracting a slitter blade guard which covers a slitter blade edge of a disk shaped slitter blade having an axis of rotation comprising; a: a web slitter cover for mounting elements, b: a slitter blade guard having a pivot axis for pivoting that is perpendicular to said slitter blade axis of rotation and pivotally mounted to said web slitter cover to pivot about said pivot axis, c: a first spring for biasing said slitter blade guard toward an orientation which exposes said slitter blade edge, d: a moveably mounted block adapted for manual and fluidic cylinder actuation for resisting said first spring and maintaining said slitter blade guard in an orientation which covers said slitter blade edge, e: a means of positioning said moveably mounted block for allowing said first spring to retract said slitter blade guard wherein said means of positioning said moveably mounted block is a fluidic air cylinder.

2. The apparatus of claim 1 wherein said slitter blade guard comprises a lip for covering said slitter blade edge.

3. An apparatus for retracting a slitter blade guard which covers the edge of a disk shaped slitter blade having an axis of rotation comprising; a: a web slitter cover for mounting elements, b: said slitter blade guard having a pivot axis that is perpendicular said slitter blade axis of rotation and pivotally mounted on said web slitter cover to pivot about said pivot axis, c: a means of biasing said slitter blade guard toward an orientation for exposing said edge of a disk shaped slitter blade mounted on said web slitter cover, d: a means of resisting and releasing said biasing means such that the slitter blade guard can be oriented to expose or cover said edge of a disk shaped slitter blade mounted on said web slitter cover by either manual or fluidic manipulation, wherein said means of resisting and releasing said biasing means is a moveably mounted block mounted on said web slitter cover wherein the moveably mounted block is biased in a resisting location causing said slitter blade guard to cover said edge, wherein said means of releasing said biasing means is a fluidic cylinder attached to said moveably mounted block.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is an Upper, Left isometric view of the Knife holder with the slitter blade guard.

(2) FIG. 2 is a left side view of the slitter blade and slitter blade guard with the guard in the blade covering position.

(3) FIG. 3 is a section view of the blade actuator cylinder, block and retract spring.

(4) FIG. 4 is a section view of the guard actuation device, which in this view is shown with the blade guard covering the blade edge.

(5) FIG. 5 is a section view of the guard actuation device, which in this view is shown with the guard retracted and the blade in the retracted not slitting position.

(6) FIG. 6 is a partial section view of the blade guard covering the blade in the not slitting position.

(7) FIG. 7 is a partial section view of the blade guard pivot on the front side, this section taken along line E-E of FIG. 2.

(8) FIG. 8 a partial section view of the blade guard pivot on the rear side this section taken along line D-D of FIG. 2.

(9) FIG. 9 is a section view of the knife holder and blade guard assembly in the blade retracted position.

(10) FIG. 10 is a section view of the knife holder and blade guard assembly in the blade extended position.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

(11) Referring to FIG. 1, the slitter blade guard 1 is mounted to a web slitter knife holder 2 for which it is used to guard personnel from the web slitter slitting blade edge 12 in FIG. 6. In the embodiment shown in FIG. 2 the web slitter cover 201 acts as a mounting base for the device 1. A guard 206 is supported in the web slitter cover 201 on two pivots 204 and 205. In this embodiment the guard is formed in an arc 405 and also has a lip 10 which covers the edge 12 of the web slitter blade 11 as shown best in FIG. 6. The web slitter cover 201 provides pivot surfaces 204A and 205A which support the guard 202 at the respective guard pivots 204 and 205 these features are best illustrated with reference to FIGS. 2, 7 and 8. This construction provides for pivoting the guard 206 about an axis 401 which is perpendicular to the web slitter blade axis 402. In this construction the guard 206 need not move far to completely expose the web slitter blade edge 12 to the slitting area 303 of FIG. 3.

(12) The embodiment includes a means of positioning the guard 206. The positioning means in this embodiment comprises a torsion spring 203 located near pivot surface 204A such that one end is attached to the web slitter cover 201 and the other end is attached to the guard 206. The attachment procedure includes loading the torsion spring 203 in such a way that the guard 206 is biased away from the web slitter blade edge 12 in direction 302 shown in FIG. 5. Referring to FIG. 4, a block 101 is located adjacent the web slitter cover 201, this block 101 is in contact with the guard 206 while the guard 206 is covering the web slitter blade edge 12. This maintains the guard 206 in a position which covers the web slitter blade edge 12.

(13) A fluidic cylinder 109, shown in cross section in FIG. 3, is used as an actuator in this embodiment. The fluidic cylinder rod 103 has two ends, 102 and 104. End 102 is connected to the block 101 and the other end 104 is attached to a piston 105. The fluidic cylinder 105 has a body 107, a compression spring 106 and a fluid inlet port 108. This fluidic cylinder rod end 102 which is connected to the block 101. The compression spring 106 pushes the piston 105 and rod 103 such that the block 101 is positioned against the back side 209 of the guard 206 and the guard 206 is held such that it covers the web slitter blade edge 12.

(14) During the slitting process the web slitter blade edge needs to be exposed to the slitting area 303. To move the guard 206 so that the web slitter blade edge 12 is exposed for use during slitting, the fluidic cylinder 109 is retracted by providing compressed fluid to the inlet port 108. This causes the fluidic cylinder 109 to pull the block 101 upward as shown in FIG. 3 by arrow 210. As explained above, the torsion spring 203 is biasing the guard 206 against the block 101, so as the block 101 moves upward, in the direction of the arrow 210, the torsion spring 203 causes the guard 206 to pivot about the pivot features 204 and 205 in the direction of the arrow 302 shown in FIG. 5. This exposes the web slitter blade edge 12 during slitting.

(15) Positioning the guard 206 to cover the web slitter blade edge 12, is provided by removing compressed fluid from the inlet port 108. This allows the compression spring 106 to overcome the torsion spring 203 and causes the cylinder rod 103 and block 101 to move downward, as shown in FIG. 4 by arrow 211. This compression spring is able to overcome the torsion spring 203 so that the guard 202 then covers the web slitter blade edge 12.

(16) At this point, a few of the features of the device should be noted. First, when the invention is in a state of rest (non-slitting use), no compressed fluid is needed to hold the guard 206 in a position that covers the web slitter blade edge 12. Only the torsion spring 203 holds the guard 206 against the block 101 and the block 101 is held in position by the compression spring 106. This accomplishes one of the goals of the invention, to cover the web slitter blade edge 12 while not in use. No effort, with the exception of disconnecting compressed fluid from the inlet port 108 is required to maintain the guard 206 in this covering position. Also, if a person should desire to expose the web slitter blade edge 12, he can simply push the block 101 toward the cylinder body 107 and cause the guard 206 to pivot. This accomplished a second goal of the invention which requires manual action to expose the web slitter blade edge 12.

(17) Next the coordination of the guard fluidic cylinder 109 and the vertical slitter blade cylinder 601 are explained. The knife holder 2 is shown in FIG. 1, FIGS. 9 and 10. In FIG. 9 the vertical slitter blade cylinder 601 is shown in the retracted position, in FIG. 10 it is shown in the extended position. This vertical movement of the blade 11 positions the blade 11 in a position for slitting. However, it should be noted that the knife holder 2 also provides a small amount of transverse motion which is not considered to be germane to the instant invention.

(18) The body of the knife holder 600 includes a fluidic cylinder 601 for actuating the slitter blade 11 vertically. The cylinder piston 602 slides vertically inside the cylinder body 603 in response to compressed air applied to the inlet air fitting 604. An oring 605 is used to seal the compressed air and prevents the compressed air from escaping out of the cylinder body 600. The cylinder piston 602 is attached to vertical rods 606 and 607 respectively. These rods are attached to the blade holder assembly 608 which includes the slitter blade 11, and the slitter blade guard 1.

(19) On the opposite side of the piston 602 is an additional rod 609. This rod is also attached to the piston 602 and passes thru the body 600 and into a concentric hole 610. Additionally, a knob 611 is attached to the end of the rod 609. The knob 611 and the body 600 enclose a spring 612 that pushes against the bottom of the knob 611 and so pushes the piston 602 and the rods 606 and 607 and the slitter blade 11 upward. This spring 612 is used to bias the piston upward and is selected such that, as air is supplied to the air inlet fitting 604 and to the guard cylinder inlet fitting 108, the guard cylinder 109 will retract first. As pressure builds up in the fluidic cylinder 601 the spring 612 is overcome and the piston 602 moves downward, taking the blade holder assembly 608 and the slitter blade 11 with it.

(20) The invention teaches that linkages and springs can be used to maintain a guard 206 in a position that covers the blade edge 12 of a web slitter and provides for the retraction of the guard 206 prior to the extension of a slitter blade 12. Additionally, this embodiment includes a means of providing a person with easy intentional access to the slitter blade edge while still guarding against accidental blade exposure.

(21) In most applications of the invention, the invention is mounted on a web slitter, which in turn is mounted to a production web handling device. While mounted in a machine compressed air is typically provided to the web slitter and also the cylinder inlet port of the invention. Detaching the web slitter from the machine includes disconnecting compressed air and so the cylinder inlet port mentioned above is also disconnected.

(22) The inventor submits the above embodiment of the invention with the expressed understanding that this embodiment is simple one possible way of applying the invention and is not to be used to limit the claims.