Improved packing and fronting tensioning mechanism and method

Abstract

The tension bracket includes a tension bolt (301) having a crown gear (311) proximate the head of the tension bolt. The tension bracket further includes a body portion (201) including a throughbore (205) configured to receive the tension bolt and an internal channel (207) disposed substantially perpendicular to the axis (215) of the tension bolt. In addition, the tension bracket includes a spring (209) disposed within the internal channel, a ratchet pin (211) partially disposed within the internal channel and configured to engage the spring at a first end, a crown gear secured to the tension bolt at a second end of the ratchet pin, and a worm gear (108) retained within the body portion and connected to an end of the tension bolt distal from the head of the tension bolt.

Description

Technical Field

[0001] This disclosure relates to printing manufacturing. More specifically, this disclosure relates to improved packing and fronting lock mechanisms for printing presses.

Summary of the Invention

[0002] In certain precision roller presses, including a roller gravure press, the substrate on which an image is printed is carried through the press over one or more webs of fibrous material, also known as boards. As part of the printing process, one or more (often three) sets of gripper mechanisms configured to hold and tension portions of material, including packing and fronting that cover the impression cylinder, are pulled onto the impression cylinder over the one or more webs and substrate being printed. Depending on the parameters of the printing application, different packing and fronting can be attached to the impression cylinder. When new packing and fronting are attached, they are held and firmly pulled to the appropriate tension by a set of gripper mechanisms on the impression cylinder.

[0003] In certain industrial-scale roller presses (e.g., some models of Komori gravure presses), the press operation frequently loosens the gripper mechanisms of the impression cylinder, resulting in the effect that the fronting and packing are no longer firmly pulled. From a practical perspective, the inability of the impression cylinder gripper mechanisms to maintain tension on the fronting and packing can potentially lead to frequent downtime during printing runs, and the operator must stop the press so that the gripper mechanisms re-tension to ensure that the packing and fronting on the impression cylinder are properly tensioned. Maintaining proper tension on the packing and fronting helps ensure accurate alignment of the printed features and minimizes the risk of ink accidentally migrating from the plate cylinder to the packing or fronting.

[0004] In certain applications, including but not limited to the precision printing of currency banknotes and security documents such as passports, the use of increasingly thicker packing and frontings has been observed to exacerbate problems associated with loose gripper mechanisms during everyday operation.

[0005] Therefore, resisting loosening of the impression cylinder gripper mechanism remains a source of technical challenges and opportunities for improvement in the art. This disclosure illustrates an improved clamping mechanism for the impression cylinder of an intaglio printing press.

[0006] In the first embodiment, the tension bracket member includes a body portion comprising a through hole configured to receive a tension bolt, an internal channel positioned substantially perpendicular to the axis of the tension bolt, a spring positioned within the internal channel, a ratchet pin positioned within a portion of the internal channel and configured to engage with the spring at a first end, and a crown gear attached to the tension bolt at a second end.

[0007] In a second embodiment, the tension bracket includes a tension bolt having a crown gear adjacent to the head of the tension bolt. The tension bracket further includes a body portion, the body portion including a through hole configured to receive the tension bolt and an internal channel positioned substantially perpendicular to the axis of the tension bolt. In addition, the tension bracket includes a spring disposed within the internal channel, a ratchet pin disposed within a portion of the internal channel and configured to engage with the spring at a first end, a crown gear fixed to the tension bolt at a second end of the ratchet pin, and a worm gear held within the body portion and connected to the end of the tension bolt distal to the head of the tension bolt.

[0008] Other technical features may be readily apparent to those skilled in the art from the following drawings, description, and claims.

[0009] Before providing the following detailed explanation, it may be beneficial to define certain terms used throughout this patent document. The terms “combine” and its derivatives refer to any direct or indirect communication between two or more elements, whether or not those elements are in physical contact with each other. The terms “include” and “comprise,” and their derivatives, mean inclusion without limitation. The term “or” means comprehensive and / or. The terms “related,” and its derivatives, include means of being contained, internally contained, enclosed, internally connected, connected, or communicating and cooperating, interleaving, juxtaposing, adjacent, combined, or having, or relating, or having the characteristics of, etc. The term “at least one of,” when used with a list of items, means that one or more different combinations of the listed items may be used, and only one item in the list may be required. For example, "at least one of A, B, and C" includes any of the following combinations: A, B, C, A and B, A and C, B and C, and A, B, and C.

[0010] Definitions of other specific terms are provided throughout this patent document. Those skilled in the art should understand that, in most but many cases, such definitions apply to the prior and future use of such defined words and phrases.

[0011] For a more complete understanding of this disclosure and its merits, similar reference numbers refer to the following description in conjunction with the accompanying drawings of the invention, where similar parts are referenced. [Brief explanation of the drawing]

[0012] [Figure 1] Figure 1 illustrates an example of a tensioning bracket for a compression cylinder, suitable for use with a bracket member, according to one embodiment of the present disclosure. [Figure 2A] Figure 2A shows examples of tension bracket members according to various embodiments of the present disclosure. [Figure 2B] Figure 2B shows examples of tension bracket members according to various embodiments of the present disclosure. [Figure 3] Figure 3 shows the operation of the tension bracket member according to some embodiments of the present disclosure. [Figure 4] Figure 4 shows an example of a crown gear according to a specific embodiment of the present disclosure. [Modes for carrying out the invention]

[0013] As background, in certain roller presses, the impression cylinder contacts the plate cylinder, applying pressure, among other things, to the moving substrate sandwiched between the impression cylinder and the plate cylinder. In intaglio presses, the pressure on the moving substrate is sufficient to push the substrate into the ink-filled recesses of the substrate, creating characteristics that make it difficult to reproduce the intaglio printing effect. To ensure that the pressure between the impression cylinder and the plate cylinder remains consistent between the impression cylinders and is applied uniformly across the plate cylinder / impression cylinder interface, a removable layer of one or more sheets of tensioned material (i.e., packing and fronting) is attached to the outside of the impression cylinder. To hold and tension the packing and fronting material, the impression cylinder has one or more (often three) sets of grippers, allowing for fine adjustment of the tension applied to the material on the outside of the impression cylinder. The packing and fronting are at least partially fitted with a gear wound around a tensioning rod at one end, and the gear at the end of the tensioning rod engages with a worm gear in a tensioning bracket (tensioning bracket) mechanism. The rotation of the worm gear causes the rotation of the tension rod, which controls the degree to which the packing and fronting wrap around the tension rod, and thereby controls the tension of the fronting and packing. In this way, the combination of the tension rod and worm gear of the tension bracket mechanism operates similarly to a tuning machine on a guitar or other fretted stringed instrument.

[0014] Figure 1 shows an embodiment of the bracket 100 that can generate and adjust tension on the gripper.

[0015] Figure 1 shows an exploded view of the components of the tensioning bracket 100 for the gripper mechanism. According to a particular embodiment, the bracket shown in Figure 1 is attached to the base (i.e., the flat end) of the impression cylinder and is configured to engage with a gear (not shown) connected to a retaining structure within the impression cylinder. In this non-limiting example, the tension of the material pulled on the impression cylinder is a function of the gear's rotation angle, which is modulated by the rotation of a worm gear 8 that engages with the gear connected to the retaining structure.

[0016] As illustrated in the explanatory example in Figure 1, the worm gear 108 is held in a pair of circular recesses in the first bracket half 106 and the second bracket half 105, and can rotate within them. The tension bolt 101 passes between the teeth of the retaining member 107 and the hollow portion of the circular recess in the second bracket half 105. Furthermore, in some embodiments, a bushing, bearing, or other friction-reducing member 104 is positioned between the worm gear 108 and the first bracket half 106. In certain embodiments, when the tension bolt 101, which is made of brass or a low-friction polymer such as TEFLON®, is rotated, the worm gear 108 rotates, and the rotation angle of the gear of the retaining structure that engages with the inclined outer threads of the worm gear 108 changes, thereby changing the tension of the packing / fronting portion mounted on the outside of the impression cylinder. In this example, the retaining member 107 is equipped with a wishbone-shaped leaf spring that provides an upward axial force to the tension bolt to theoretically hold the tension bolt in place once tightened. However, experience shows that the retaining member 107 is often insufficient to resist the loosening forces generated by the routine operation of a press, which causes the tension bolt to rotate and release the tension in the packing / fronting layer. The inability to hold the tension bolt in a position related to the proper tension of the packing / fronting layer can present significant operational problems, resulting in downtime to check and re-tension the tension bolt that operates the worm gear of the gripper mechanism.

[0017] Figure 2A shows an example of the second bracket half 200, which can be replaced with the second bracket half 105 in Figure 1 to dramatically reduce the tendency of the worm gear to rotate the tension in the packing and fronting during operation, and also to move the tension bolt away from its initially set position, thereby releasing the tension in the packing / fronting attached to the impression cylinder. Thus, in certain embodiments of this disclosure, the need to check and retighten the tension bolt, which is set and partially maintained by the worm gear held in the second bracket half 200, during routine operation of the press can be greatly reduced.

[0018] Referring to the explanatory example in Figure 2A, a second bracket half 200 according to a particular embodiment of the present disclosure is shown. In this example, four figures of the bracket half 200 are provided. According to a particular embodiment, the second bracket half of Figure 2A is reverse-compatible with other components (e.g., the first bracket half, tension bolts, retaining bolts, and worm gears) of other tension brackets (e.g., the tension bracket shown in Figure 1), and the second bracket half 200 can replace the original second bracket half.

[0019] According to certain embodiments, the second bracket half 200 is made of metal (e.g., aluminum or mild steel) and has a raised portion having a pair of through holes 203a and 203b drilled to accommodate the shank of a bolt that holds the second bracket half to the first bracket half (e.g., the first bracket half 6 in Figure 1). Furthermore, the second bracket half 200 has a flat portion having a third through hole 205 configured to hold a bushing through which a tension bolt (e.g., the tension bolt 101 in Figure 1) passes, and in some embodiments, the lower flange of a worm gear passes through. According to certain embodiments, the tension bolt has a head with an outer surface on which a crown gear can be attached.

[0020] Referring to the non-limiting example in Figure 2A, in certain embodiments, the second bracket half 200 is positioned substantially perpendicular to the axis of the tension bolt in the first plane 215 and includes an internal channel 207 oriented slightly away from the axis of the tension bolt in the second plane, so that the extended centerline 213 of the internal channel does not pass through the central axis 215 of the tension bolt. Rather, in certain embodiments, when viewed from above (i.e., along the central axis of the tension bolt), the extended centerline of the internal channel passes through the tension bolt along a chord that does not include the center of the tension bolt. According to some embodiments, a spring 209 and a ratchet pin 211 are positioned within the internal channel 207, so that the spring 209 presses the ratchet pin 211 against a crown gear attached to the head of the tension-applying bolt. The engagement of the ratchet pin 211 with the crown gear fixed to the head of the tension bolt provides a consistent retaining force to the tension bolt and prevents the tension bolt from loosening during the normal operation of the press.

[0021] Figure 2B shows further examples of the second bracket half 250 according to various embodiments of the present disclosure. For convenience of cross-referencing, elements common to both Figures 2A and 2B are similarly numbered.

[0022] Referring to the non-limiting example in Figure 2B, in some embodiments, instead of a bushing, a needle bearing 251 is seated in a through-hole through which the tension bolt passes. Tests have shown that supporting the tension bolt on a roller bearing can provide smoother operation of the tension bolt and further reduce the occurrence of stiction or other force imbalances in the tension mechanism, which over time can lead to fluctuations in packing tension, and consequently, jams and stoppages.

[0023] As shown in FIG. 2B, the second bracket half according to a particular embodiment can be manufactured as a single member (e.g., machined from a single steel billet) or as two or more pieces held together under the tension of a retaining bolt that holds the second bracket half to the shell. For example, the second bracket half 250 includes a first portion 253 and a second portion 255, which are held together by bolts within through holes 203a and 203b. In some embodiments, when a laminated multi-part structure is used for the second bracket half, one or more dowel pins (e.g., dowel pins 257a and 257b) are disposed between the laminated parts of the second bracket half to ensure proper alignment of the parts and resist loosening forces.

[0024] FIG. 3 shows, at 301 in a particular embodiment, the aspect of a spring-loaded ratchet pin where the second bracket half engages a crown gear 305 to resist an undesirable movement of a tension bolt to which the crown gear is attached.

[0025] Referring to the non-limiting example of FIG. 3, a top view of the head of a tension bolt 300 (shown as a hexagon within crown gear 305), a spring-loaded ratchet pin 301, and the heads of a pair of bolts 303a and 303b that attach the second bracket half to the first bracket half are shown in the figure. In this illustrative example, the rotation of bolt 300 controls the rotation of a worm gear (e.g., worm gear 108 of FIG. 1) that engages a gear on the retaining mechanism. In this way, the tension of the packing on the shell and the fronting is a function of the rotational position of bolt 300. As bolt 300 rotates, the tension of the packing on the cylinder and the fronting changes depending on the direction of movement of bolt 300.

[0026] According to various embodiments, the spring load ratchet pin 301 engages with the teeth of the crown gear 305 of the tension bolt 300 with a slight offset, as shown on the lower left side of the head of the crown gear 305. In certain embodiments, the end of the ratchet pin 301 may be connected to or in contact with a compression spring (e.g., spring 209 in FIG. 2A) disposed within an internal channel of the tensioning bracket. In this way, the spring provides a force to maintain contact between the ratchet pin and the crown gear 305. In embodiments where the tension bolt is a right-hand thread, the ratchet pin 301 can provide a torsional force that resists counterclockwise movement (i.e., loosening) of the tension bolt 300 due to vibrations or other forces that occur during operation of the printing machine. At the same time, due to the relatively acute angle of engagement between the ratchet pin 301 and the crown gear 305, certain embodiments according to the present disclosure allow movement of the tension bolt in both directions when a relatively large torque is applied to the bolt by a tool adapted to fit the tension bolt. In the non-limiting example of FIG. 3, the teeth of the crown gear 305 are biased to engage the ratchet pin 301 at different engagement angles depending on the direction in which the tension bolt 300 rotates, but embodiments according to the present disclosure are not so limited and include embodiments where the gear surface of the crown gear 305 engages the ratchet pin 301 at similar angles in both the clockwise and counterclockwise directions.

[0027] FIG. 4 shows multiple views of an example of a crown gear 400 according to some embodiments of the present disclosure.

[0028] Referring to the non-limiting example in Figure 4, a crown gear according to a particular embodiment of the present disclosure is made from a metal (e.g., tool steel or case-hardened steel) and comprises an inner surface 401 that slides on and engages with the tool engagement surface of a tension bolt. According to a particular embodiment, the tolerance between the inner surface 401 and the head of the tension bolt is such that the crown gear 400 is press-fitted onto the head of the tension bolt. In this exemplary embodiment, the inner portion has a substantially hexagonal outer shape that allows the crown gear to be press-fitted onto the head of the tension bolt. In some embodiments, the inner portion of the crown gear may be configured to engage with other bolt heads, such as socket head machine screws. According to some embodiments, the crown gear 400 further comprises an outer profile 403 having a set of teeth configured to engage with a spring-loaded ratchet pin of a second bracket half. As stated with reference to the exemplary embodiment in Figure 3, according to a particular embodiment, the outer profile 403 of the crown gear 400 may have a gear tooth profile that is biased to provide greater resistance to rotation in one direction (e.g., the loosening direction) than in the other direction of rotation.

[0029] Examples of tension bracket members according to various embodiments of this application include a tension bracket member comprising a body portion, the body portion comprising a through hole configured to receive a tension bolt, an internal channel positioned substantially perpendicular to the axis of the tension bolt, a spring positioned within the internal channel, a ratchet pin positioned within a portion of the internal channel and configured to engage with the spring at a first end, and a crown gear attached to the tension bolt at a second end.

[0030] Examples of tension bracket members according to various embodiments of this application include tension bracket members comprising bushings positioned within through holes.

[0031] Examples of tension bracket members according to various embodiments of this application include tension bracket members comprising needle bearings disposed within through holes.

[0032] Examples of tension bracket members according to various embodiments of this application include a tension bracket member comprising a main body comprising two sections of material aligned by two or more dowel pins.

[0033] Examples of tension bracket members according to various embodiments of this application include a tension bracket member in which an internal channel is positioned substantially perpendicular to the axis of a tension bolt in a first plane and oriented slightly away from the axis of the tension bolt in a second plane.

[0034] Examples of tension bracket members according to various embodiments of this application include a tension bracket member in which an extended centerline of an internal channel passes through the chord of a tension bolt, and the chord of the tension bolt does not include the centerline of the tension bolt.

[0035] Examples of tension brackets according to some embodiments of the present disclosure include a tension bracket comprising: a tension bolt having a crown gear adjacent to the head of the tension bolt; a body portion having a through hole configured to receive the tension bolt and an internal channel positioned substantially perpendicular to the axis of the tension bolt; a spring disposed within the internal channel; a ratchet pin disposed within a portion of the internal channel and configured to engage with the spring at a first end; a crown gear fixed to the tension bolt at a second end of the ratchet pin; and a worm gear held within the body portion and connected to the end of the tension bolt distal to the head of the tension bolt.

[0036] Examples of tension brackets according to some embodiments of the present disclosure include tension brackets comprising bushings positioned within through holes.

[0037] Examples of tension brackets according to some embodiments of the present disclosure include tension brackets comprising needle bearings positioned within through holes.

[0038] Examples of tension brackets according to some embodiments of the present disclosure include a tension bracket having a body portion comprising two sections of material aligned by two or more dowel pins.

[0039] Examples of tension brackets according to some embodiments of the present disclosure include a tension bracket in which an internal channel is positioned substantially perpendicular to the axis of a tension bolt in a first plane and oriented slightly away from the axis of the tension bolt in a second plane.

[0040] Examples of tension brackets according to some embodiments of the present disclosure include a tension bracket in which an extended centerline of an internal channel passes through the chord of a tension bolt, and the chord of the tension bolt does not include the centerline of the tension bolt.

[0041] Examples of tension brackets according to some embodiments of the present disclosure include a tension bracket having an external profile biased such that the crown gear provides greater resistance to rotation in a first direction than in a second direction.

[0042] An example of a method according to a particular embodiment of the present disclosure includes a method comprising attaching a first end of a fronting to a retaining mechanism in a stamping cylinder, the retaining mechanism comprising a tension rod for holding the first end of the fronting and a first gear positioned along the axis of rotation of the tension rod, and a tension bracket comprising a tension bolt having a crown gear adjacent to the head of the tension bolt, a body portion and configured to receive the tension bolt and rotate the tension bolt to set tension on the fronting.

[0043] An example of a method according to a particular embodiment of the present disclosure includes a method by which tension in the fronting portion is maintained during the operation of the impression cylinder via the engagement of a ratchet pin with the gear surface of the crown gear.

[0044] Although this disclosure has been described using various embodiments, various changes and modifications may be suggested to those skilled in the art. This disclosure is intended to include changes and modifications that fall within the scope of the claims.

[0045] This disclosure should not be construed as implying that any particular element, step, or function is an essential element, step, or function that must be included in the claims. Furthermore, the claims are not intended to invoke 35 U.S.C. § 112(f) unless the exact word “means for” is followed by a particle.

Claims

1. A tension bolt (311) for the impression cylinder of a printing press, comprising a crown gear (305) attached to the head of the tension bolt, A main body portion (201) comprising a through hole (205) configured to receive the tension bolt, and an internal channel (207) positioned substantially perpendicular to the axis (215) of the tension bolt, A spring (209) is placed within the internal channel, A ratchet pin (211) is configured to be partially positioned within the internal channel, engage with the spring at a first end, and engage with a crown gear fixed to the tension bolt at a second end, A worm gear (108) is held within the main body portion and connected to the end of the tension bolt distal to the head of the tension bolt, Equipped with, The worm gear is configured to engage with a first gear connected to a holding mechanism within the impression cylinder, and to set tension on the packing / fronting portion attached to the outside of the impression cylinder by changing the rotation angle of the first gear of the holding mechanism via the worm gear through the rotation of the tension bolt. The ratchet pin engages with the gear surface of the crown gear, thereby preventing the tension bolt from loosening during the operation of the impression cylinder. Tension bracket.

2. The tension bracket according to claim 1, further comprising a bushing (104) disposed within the through hole.

3. The tension bracket according to claim 1, further comprising a needle bearing (251) disposed within the through hole.

4. The tension block according to claim 1 comprises two sections of material (253, 255) aligned by two or more dowel pins (257a, 257b) in the main body portion. racket.

5. The tension bracket according to claim 1, wherein the internal channel is positioned substantially perpendicular to the axis of the tension bolt in a first plane and oriented slightly away from the axis of the tension bolt in a second plane.

6. The tension bracket according to claim 5, wherein the extended center line (213) of the internal channel passes through the chord of the tension bolt, and the chord of the tension bolt does not include the center line of the tension bolt.

7. The tension bracket according to claim 1, wherein the crown gear has an external profile biased to provide greater resistance to rotation in the first direction than to rotation in the second direction.

8. A method for maintaining the tension of the fronting of a printing press, The above method involves attaching the first end of the fronting section to a holding mechanism inside the impression cylinder, The tension bracket described in claim 1 is provided, Includes, The worm gear of the tension bracket is configured to engage with a first gear connected to the retaining mechanism. To set tension on the fronting, rotate the tension bolt of the tension bracket. method.

9. The engagement of the ratchet pin with the gear surface of the crown gear, which is attached to the head of the tension bolt, maintains the tension of the fronting during the operation of the impression cylinder. The method according to claim 8.

Images