Title of Invention

A STAMPING ROLLER FOR A STAMPING APPARATUS

Abstract

The present invention relates to a stamping roller for a stamping apparatus having a central main body with stamping punch portions, wherein said stamping punch portions being spaced from each other in a peripheral direction, and at least one punch ring fixed to said main body, each of said at least one punch rings containing spacer rings at two mutually axially-spaced edge portions thereof for defined contact with at least one associated backing roller, and wherein said at least one punch ring contains said stamping punch portions between said spacer rings wherein each of said at least one punch ring has a first coefficient of thermal expansion and said main body has a second coefficient of thermal expansion different from the first coefficient of thermal expansion such that each of said at least one punch ring is mounted over said main body is displaceable relative to said main body at ambient temperature and at an elevated stamping operating temperature of said stamping roller, said punch ring being securely fixed to said main body and wherein said each punch ring further comprises a heat insulating portion between said lateral spacer rings and between adjacent stamping punch portions, said stamping roller further comprising cover means laterally adjoining each punch ring. PRICE: THIRTY RUPEES.

Full Text

temperature at the stamping punch portions of the respective punch ring and in particular precise regulation of the temperature at the front or punching surfaces of the individual stamping punch portions. For the purposes of accurate temperature regulation of the individual stamping punch portions of the/each punch ring, the respective punch ring is desirably provided with temperature-measuring sensors connected to a regulating device which suitably acts on said heating device. Thermal separation between the stamping punch portions or the front or stamping surfaces thereof can be achieved by the/each punch ring preferably having a heat-insulation portion between the two lateral spacer rings and between the adjacent stamping punch portions. Those heat-insulation portions advantageously have an outside surface which corresponds to the outside surface of the stamping roller. That affords the advantage that the substrate which is to be stamped or embossed and the stamping foil which is introduced simultaneously with the substrate between the stamping roller and the at least one associated pressure or backing roller cannot suffer from any undesired folding into the intermediate spaces between adjacent stamping punch portions; it will be appreciated that such folding would adversely affect the quality of the stamping. The above-mentioned heat-insulation portions have insulating properties such that the surface temperature of the heat-insulation portions does not exert any effect, that is to say influence, on the stamping foil, so that the heat-insulation portions do not give rise to any undesired preliminary activation of the adhesive layer and/or stretching of the carrier of the stamping foil. While, in the case of a smooth stamping roller as is disclosed for example in above-mentioned DE 32 10 551 C2, the pressure or backing rollers continuously and uniformly roll against the cylindrical peripheral surface, the rolling movement is correspondingly discontinuous in the case of a stamping roller with spaced-apart, individual stamping punch portions. In other words, at the pressures required for carrying out the stamping operation, the backing or pressure rollers can be moved into the intermediate spaces between adjacent stamping punch portions. The heat-insulation portions disposed between adjacent stamping punch portions are not suitable for applying the necessary counteracting forces; more specifically, due to the material used, they yield or deflect slightly. Serious problems can arise, in—particular in the event of so-called" distortion of the stamping roller, as often cannot be reliably excluded in consideration of the temperatures employed. It is here that the present invention, using simple means, provides a reliable remedy by virtue of the fact that disposed laterally beside the spaced-apart stamping punch portions are the two spacer rings against which the at least one associated pressure or backing roller of the stamping apparatus presses. When dealing with sensitive substrates to be stamped and/or when using high line pressures between the stamping roller and the at least one pressure or backing roller, the spacer rings can leave behind on the stamped substrate clearly marked impressions which can then limit the capacity for overprinting. In order to remedy that disadvantage, the two spacer rings of the/each punch ring in the stamping roller according to the invention can be provided with chamfer surfaces. Designing the respective pair of spacer rings with such chamfer surfaces affords the advantage that overprintability is not restricted. In the stamping roller according to the invention, lateral cover means advantageously adjoin the/each punch ring. The cover means can each comprise a respective metal sheet. They serve not only to provide a suitable configuration for the stamping cylinder, but in addition they also serve to provide for thermal insulation for the central main body, in an outward direction. More specifically, the main body is desirably also provided with a heating device. The heating device may be formed for example by commercially available electrical heating cartridges or inserts. It has been found advantageous if at least one elongate bar element projects away from the stamping roller according to the invention, that is to say from the outside peripheral surface of its main body, which bar element is oriented in the axial direction of the main body and is formed laterally beside the at least one punch ring with suction openings. By means of the suction openings which can be brought into fluid communication with a reduced-pressure source by way of suitable hose conduits, it is reliably possible to fix a substrate to be stamped, to the stamping roller. In this case, in the operation of stamping a so-called endless substrate, the advance movement of the substrate is guaranteed in particular by a suitable clamping effect as between the spacer rings of the/each punch ring and the associated pressure or backing rollers. When stamping substrates in sheet form, that is to saynrrthe form of individual portions, substrate transportation is effected in particular by the elongate bar elements with their suction openings. In that case, the leading part of the sheet or individual portion is desirably engaged in a defined manner by means of the suction openings. In that case, the sheets or portions are pushed onto the at least one bar element for example by a feed roller which is arranged apstream of the stamping station. In order precisely definedly to limit that advance movement, it is preferable if, in a stamping roller of the last-mentioned kind, the at least one bar element has abutment ribs which are disposed laterally beside the at least one punch ring and which project radially beyond the at least one punch ring. The respective sheet to be stamped comes to bear against those abutment ribs, by way of its front adge, in an accurately defined position, and is sucked against the bar element and thus against the stamping roller by way of the suction openings in the elongate bar element. After the corresponding stamping operation las been carried out, the reduced pressure is discontinued. After that, compressed air can be blown out through the suction openings, whereby the stamped substrate sheets or individual portions are ejected from the abutment ribs or the stamping roller and are taken over for example by :onveyor belts. The stamping roller according to the inventory, consequently has a large lumber of advantages, such as: - time-saving interchangeability of a complete punch ring for another Dunch ring with a desired stamping punch portion shape and pitch arrangement; stamping roller diameter and periphery variable within certain limits; rapid attainment of a stable operating temperature by separate leating of the main body and the at least one punch ring; - secure reliable mounting and fixing of the at least one punch ring )n the central main body as a result of the press fit at the elevated operating temperature of the stamping roller; - reliable and secure substrate transportation both when dealing with jndless substrate material and also when dealing with substrate material in sheet form or in the form of individual portions because the clamping iction is produced directly laterally beside the individual punch portion surfaces or stamping punch portions; - no problems due to distortion of the stamping roller; stampability, without problems, of "substrates of different thicknesses because the associated spacer rings are disposed immediately beside the individual stamping punch portions so that defined conditions are afforded not only at the outer edges of the stamping roller but also directly laterally beside each of the stamping punch portions; and avoiding undesired changes in the print image with changes in stamping temperature and consequently a change in the diameter of the stamping roller. Further advantages of the stamping roller according to the invention are that the temperature at the front or punching surfaces of the stamping punch portions can be very accurately and easily regulated and that thermal separation can be easily effected by means of heat-insulation portions between said stamping surfaces of the stamping punch portions and the non-stamping intermediate spaces between the stamping punch portions. The heat-insulation portions are to be of a cylindrical shape in order to keep the length of the foil which is drawn off, corresponding to the arcuate length of the cylindrical configuration, as, without such heat-insulation portions, the foil would follow the polygonal shape from one punch portion to another. As a result of this, the length of foil drawn off would be shorter than the pitch arrangement or spacing of the punch portions on the cylinder or the pitch arrangement of the imprints on the sheet of paper or the like, which is to be stamped. That would severely impair regulatability. The last-mentioned deficiencies are eliminated in a simple fashion, by virtue of the provision of the heat-insulation portions. Accordingly, the present invention provides a stamping roller for a stamping apparatus having a central main body with stamping punch portions, wherein said stamping punch portions being spaced from each other in a peripheral direction, and at least one punch ring fixed to said main body, each of said at least one punch rings containing spacer rings at two mutually anally-spaced edge portions thereof for defined contact with at least one associated backing roller, and wherein said at least one punch ring contains said stamping punch portions between said spacer rings wherein each of said at least one punch ring has a first coefficient of thermal expansion and said main body has a second coefficient of thermal expansion different from the first coefficient of thermal expansion such that each of said at least one punch ring is mounted over said main body is displaceable relative to said main body at ambient temperature and at an elevated stamping operating temperature of said stamping roller, said punch ring being securely fixed to said main body and wherein said each punch ring further comprises a heat insulating portion between said lateral spacer rings and between adjacent stamping punch portions, said stamping roller further comprising cover means laterally adjoining each punch ring. Further details, features and advantages are apparent from the following description of an embodiment, illustrated in the drawing, of the stamping roller according to the invention. With reference to the accompanying drawings, in which Figure 1 is a view, which for the major part is cut away, of an embodiment of the stamping roller having four punch rings, Figure 2 is a view in cross-section through the stamping roller shown in Figure 1, Figure 3 is a side view of a punch ring of the stamping roller shown in Figure 1, Figure 4 shows an angled section through the punch ring shown in Figure 3, and Figure 5 is a heavily distorted sectional view, not true to scale, of a portion of a punch ring and an associated pressure or backing roller. Figure 1 shows an embodiment of the stamping roller 10 which is intended for a stamping apparatus, having a central main body 12 which is in the form of a tubular sleeve. A flange 14, 16 is fixed to each of the two axial ends of the main body 12. The flange 14 is the flange at the drive end. The stamping roller 10 is driven by way of the flange 14. The drive is provided by way of a non-rotatable divisible coupling which is not shown in Figure 1. Such a design configuration with divisible coupling gives the advantage that the stamping roller 10 can be replaced, in a time-saving manner. Fixed to the two axial ends of the stamping roller 10 or to the flanges 14, 16 are spacer or runner rings 18 which determine the diameter of the stamping roller 10. Those spacer rings 18 serve to support a backing roller carrier (not shown) of the stamping apparatus. Fixed to the tubular main body 12 are four punch rings 20 of which one is shown in Figures 3 and 4 in a side view and in section. The punch rings 20 are spaced from each other in the axial direction and, in terms of dimensions and material, are matched to the main body 12 in such a way that each punch ring 20 is slidable or displaceable on the main body 12 at ambient temperature"while at elevated stamping or operating temperature of the stamping roller 10 thermal expansion fixes the respective punch ring 20 on the main body 12. The main body 12 therefore comprises a material which has a higher coefficient of thermal expansion than the material for the punch rings 20. Each punch ring 20 is provided with a heating device 22. These heating devices are desirably electrical resistance heating devices. The power thereof is such that the entire process heat can be applied. Each of the punch rings 20 has its own electrical regulating circuit so that the individual punch rings can not only be replaced without problem, but they can also be regulated independently of each other as desired. As can be seen from Figures 1 and 3, each punch ring 20 is formed with a row of stamping punch portions 24 which are spaced from each other. Laterally beside the stamping punch portions 24 the/each punch ring 20 is formed with-spacer rings 26 against which the respectively associated pressure roller 28 (see Figure 5) bears. A side portion 30 laterally integrally adjoins each of the two spacer rings 26. Each of the two side portions 30 has a peripherally extending annular groove 32 which is provided for fixing an associated lateral cover means 34. A respective heat-insulation portion 36 is disposed between adjacent stamping punch portions 24 and the two lateral spacer rings 26. One of those heat-insulation portions 36 is indicated by hatching in Figure 3. The heat-insulation portions 36 are for example screwed fast between the two spacer rings 26, as is indicated by references 38. As can be seen from Figure 5, the two spacer rings 26 of the corresponding punch ring 20 are provided with chamfer surfaces 40. As can be seen from Figure 2, four elongate bar elements 44 project away from the outside peripheral surface 42 of the main body 12; the bar elements 44 are provided laterally beside the punch rings 20 with suction openings 46, as Figure 1 shows. The elongate bar elements 44 also have abutment ribs 48 (see Figure 2) which are disposed laterally beside the punch rings 20 and which project radially beyond the punch rings 20. The abutment ribs 48 serve for accurately defined contact with the front edge of each substrate to be stamped, which is in sheet form or in the form of an individual portion. WE CLAIM: 1. A stamping roller (10) for t stamping apparatus having a central main body (12) with stamping punch portions (24), wherein said stamping punch portions (24) being spaced from each other in a peripheral direction, and at least one punch ring (20) fixed to said main body (12), each of said at least one punch rings (20) containing spacer rings (26) at two mutually axially-spaced edge portions thereof for defined contact with at least one associated backing roller (28), and wherein said at least one punch ring (20) contains said stamping punch portions (24) between said spacer rings (26) wherein each of said at least one punch ring (20) has a first coefficient of thermal expansion and said main body (12) has a second coefficient of thermal expansion different from the first coefficient of thermal expansion such that each of said at least one punch ring (20) is mounted over said main body (12) is displaceable relative to said main body (12) at ambient temperature and at an elevated stamping operating temperature of said stamping roller (10), said punch ring (20) being securely fixed to said main body (12) and wherein said each punch ring (20) further comprises a heat insulating portion (36) between said lateral spacer rings (26) and between adjacent stamping punch portions (24), said stamping roller further comprising cover means (34) laterally adjoining each punch ring. 2. The stamping roller according to claim 1 wherein said punch ring (20) is provided with a heating device (22). 3. The stamping roller according to claim 2, wherein at least one elongate bar element (44) is oriented in the axial direction of said main body (12) and has an outside peripheral surface (42) from which said elongate bar element (44) projects, said elongate bar element (44) is provided laterally beside said at least one punch ring (20) with suction openings (46). The stamping roller according to claim 3 wherein said at least one bar element (44) has abutment ribs (48) which are provided laterally beside said at least one punch ring (20) and which project radially beyond said at least one punch ring (20). The stamping roller according to claim 1 or 2 wherein said two spacer rings (26) of said each punch ring (20) are provided with chamfer surfaces (40). A stamping roller for a stamping apparatus, substantially as herein described with reference to the accompanying drawings.

Documents:

1255-mas-1995 abstract.jpg

1255-mas-1995 abstract.pdf

1255-mas-1995 claims.pdf

1255-mas-1995 correspondence -others.pdf

1255-mas-1995 correspondence -po.pdf

1255-mas-1995 description (complete).pdf

1255-mas-1995 drawings.pdf

1255-mas-1995 form-1.pdf

1255-mas-1995 form-13.pdf

1255-mas-1995 form-26.pdf

1255-mas-1995 form-4.pdf

1255-mas-1995 form-9.pdf

1255-mas-1995 others.pdf

1255-mas-1995 petition.pdf