Metal working – Foil or other thin sheet-metal making or treating
Reexamination Certificate
2001-05-14
2003-02-18
Vidovich, Gregory M. (Department: 3726)
Metal working
Foil or other thin sheet-metal making or treating
C029S017900, C029S017100, C029S424000, C072S421000
Reexamination Certificate
active
06519821
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a hot stamping method and to a hot stamping device particularly suitable for performing the method.
2. Description of the Prior Art
Hot stamping or embossing methods and devices of this type are used for the hot stamping or embossing of material layers to be stamped with stamping product on a stamping foil web. The material layer, also referred to as printing material and which can be a sheet or a web material, is moved at a normally uniform material layer speed through a stamping gap and the stamping foil web is jointly moved in such a way that a stamping foil web portion during a stamping interval moves at the same speed as the material layer through the stamping gap. This is necessary so that the stamping product, which can be discreet, juxtaposed or successively arranged stamping units such as images, texts, etc., or parts to be stamped on or areas of ink or colour coatings, can pass in undistorted and unsmeared manner onto the material layer to be stamped and consequently the stamping foil web does not tear during the stamping interval.
In order to minimize waste of the often expensive stamping foil or film material, in the case of stamping foils the aim is to keep as small as possible the unused or unstamped foil web areas. It has already been proposed for this purpose to bring successively positioned stamping product areas to be stamped on the stamping foil web closer together than successive stamping locations on the material web. This can be brought about in that the stamping foil web outside a stamping interval is moved at least temporarily at a foil web speed differing from the material layer speed. The necessary speed changes to the stamping foil web can be obtained by foil accelerating means and a foil acceleration can be both a speed increase/decrease and a direction reversal of the stamping foil web movement.
A hot stamping rotary press providing a feed speed rise upstream of a stamping interval and a feed speed drop after a stamping interval with respect to the stamping foil is disclosed by DE 29 31 194. In this case the stamping foil web is always moved in the main movement direction thereof, the speed in said direction varying and never being higher than the material layer speed.
To reduce the accelerative forces acting on the possibly tension-sensitive stamping foil web, DE 37 13 666 already proposes to pull back by a certain amount the stamping foil web upstream of every new stamping interval, so as to permit a longer starting distance and optionally also a longer decelerating distance, so that acceleration strains on the stamping foil web can be reduced. Here again the foil web speed in the main conveying direction at no time exceeds the material layer speed.
SUMMARY OF THE INVENTION
The object of the invention is to so further develop hot stamping methods and devices of the aforementioned type that there is a particularly effective utilization of the stamping product on the stamping foil web.
For solving this problem the invention proposes a hot stamping method for stamping material layers with a stamping product present on a stamping foil web, in which a material layer is moved at a material layer speed through the stamping gap and the stamping foil web is jointly moved in such a way that a stamping foil web portion during a stamping interval is moved at the same speed as the material layer through the stamping gap whereas, outside a stamping interval, the stamping foil web portion is at least temporarily moved at a foil web speed differing from the material layer speed, wherein the following steps are provided:
stamping a first stamping product area of the stamping foil web during a first stamping interval at a first stamping location,
stamping a second stamping product area, following the first stamping product area in the web direction, during a following, second stamping interval at a second stamping location,
acceleration of the stamping foil web between the first and second stamping intervals in such a way that a space between succeeding stamping product areas of the stamping foil web is larger than an unstamped area between associated, succeeding stamping locations of the material layer. There is further provided hot stamping device comprising:
a stamping press, in which between a cylinder and a movable back pressure element, a stamping gap is formed at least during a stamping interval, and
foil conveying means for producing, at least during a stamping interval, a speed of a stamping foil web portion with being the same as the speed of a material layer moved with a material layer speed through the stamping gap,
the foil conveying means being constructed as foil acceleration means in such a way that the stamping foil web portion, outside the stamping intervals, at least temporarily is movable with a foil web speed differing from the material layer speed;
wherein the stamping foil web can be accelerated by the foil accelerating means between a first stamping interval and a following, second stamping interval in such a way that a space provided with the stamping product between succeeding stamping product areas of the stamping foil web delivering stamping product is larger than an unstamped area between associated, succeeding, stamping product-receiving stamping locations on the material layer and which is particularly suitable for performing this method. Preferred further developments are given in the dependent claims. By reference the wording of all the claims is made into part of the content of the description.
A hot stamping method according to the invention is characterized in that at least once during a stamping pass during a first stamping interval a first stamping product area of the stamping foil web is stamped at a first stamping location of a material layer, that during an immediately following, second stamping interval on a second stamping location of a material layer is stamped a second stamping product area of the stamping foil web following the first stamping product area in the web direction and that between these stamping intervals the stamping foil web is accelerated in such a way that between the successive stamping product areas of the stamping foil web is formed a gap or space still provided with the stamping product and which, measured in the web direction, is larger than an unstamped area between the succeeding stamping locations on the material layer. For this purpose and diverging from all known solutions, the stamping foil web in the acceleration phase between the succeeding stamping intervals is moved at least temporarily in the main movement direction of the stamping foil web at a web speed which is higher than the normally uniform material layer speed. The web speed can e.g. be more than 5, 10 or 20% higher than the material layer speed, but is in general less than 50% higher. In the acceleration phase there is at least one deceleration or speed reduction of the stamping foil web to ensure that the latter in the stamping interval following the acceleration phase moves at the same speed as the material layer. The speed rise and speed drop are matched to one another in such a way that in the acceleration period between the stamping intervals a stamping foil web portion is moved through the stamping gap whose length exceeds the length of the material layer portion passing at the same time through the stamping gap.
As a result of this apparently contradictory measure with respect to the sought minimizing of foil web waste, it is possible to ensure that the space between the directly succeeding, already stamped stamping product areas is increased compared with the spacing of the associated stamping locations to such an extent that in a time-succeeding stamping step it is still possible to stamp stamping product from this enlarged intermediate area. A gap between succeeding stamping product areas, which is e.g. too small to enable to make economies according to the above-described, conventional methods, can also be deliberately stretched or lengthen
Nath Gary M.
Nath & Associates PLLC
Reiley Don
Vidovich Gregory M.
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