Claims
- 1. A method of maintaining constant a set of cutting conditions at a rotary punch for producing profiled and straight cuts on moving webs or flat individual articles of foil or paper particularly for manufacturing hygiene products, envelopes, flat bags or the like, by means of a rotating cutting tool having a longitudinal bore and a working outer periphery and a fixed or rotating opposing tool having a longitudinal bore and a working outer periphery which are arranged within a frame, wherein a cutting edge or edges are on said working outer periphery of said cutting tool and describe a cylindrical envelope and hit the opposing tool at the instant of the cut and wherein under operating conditions the rotary punch operating temperature dependent on the product and on the environment results, said method comprising
- monitoring in a bore near to said working outer periphery of said cutting and opposing tools and controlling the heating of the rotary punch by thermal conduction to an adjustable and predeterminable constant temperature, by means of heat sources, coaxially disposed in said longitudinal bores, said constant temperature being no less than the rotary punch operating temperature which results under operating conditions;
- adjusting the space of the cylindrical envelope described between the cutting tool and the opposing tool so as to set the cutting conditions thereof;
- maintaining the rotary punch at said temperature;
- wherein the opposing tool is heated and the heating of the cutting tool and the opposing tool is by means of integrated heating elements coaxially disposed in said longitudinal bores and the temperature is monitored by means of integrated heat sensors in a bore near to said working outer periphery of said cutting and opposing tools; and
- wherein the temperature is controlled by a common, stationary control device which is connected with all the heating elements and temperature sensors.
- 2. The method as claimed in claim 1, wherein the rotary punch frame has a base plate and the method further includes heating said base plate by means of at least one integrated heating element, and monitoring the temperature by means of an integrated temperature sensor.
- 3. The method as claimed in claim 1, wherein the rotary punch frame has side portions and the method further includes heating said side portions by means of heating elements, and monitoring the temperature by means of integrated temperature sensors.
- 4. The method as claimed in claim 1, wherein the rotary punch frame has an upper bridge and the method further includes heating said upper bridge by means of at least one integrated heating element, and monitoring the temperature by means of an integrated temperature sensor.
- 5. The method as claimed in claim 1 wherein the temperature of the cutting and opposing tools are increased by a monitored amount so as to maintain a cut position.
- 6. The method as claimed in claim 5, which further comprises automatically effecting a wear adjustment after a predetermined number of cuts by means of a monitored increase of the temperature of the cutting tool and opposing tool.
- 7. Apparatus for maintaining constant a set of cutting conditions at a rotary punch for producing profiled and straight cuts on moving webs or flat individual articles of foil or paper, particularly for manufacturing hygiene products, envelopes, flat bags or the like, by means of a rotating cutting tool having a longitudinal bore and a working outer periphery and a fixed or rotating opposing tool having a longitudinal bore and a working outer periphery which are arranged within a frame, wherein the cutting edge or edges are on said working outer periphery of said cutting tool and describe a cylindrical envelope and hit the opposing tool at the instant of the cut and wherein under operating conditions a rotary punch operating temperature dependent on the product and the environment results, said apparatus comprising
- an integrated heating element coaxially disposed in said longitudinal bore of said cutting tool and an integrated temperature sensor included in a bore near to said working outer periphery of said rotary punch;
- an integrated heating element coaxially disposed in said longitudinal bore of said opposing tool and an integrated temperature sensor included in a bore near to said working outer periphery of said opposing tool for tempering so as to maintain constant and set the spacing of the cylindrical envelope described by the cutting edge or edges from the opposing tool;
- said tempering resulting in a temperature of said rotary punch which is no less than the rotary punch operating temperature which results under operating conditions; and
- means for adjusting the spacing of the cylindrical envelope described by the cutting edge or edges from the opposing tool so as to set the cutting conditions thereof subsequent to the tempering of the rotary tool and opposing tool.
- 8. The apparatus as claimed in claim 7, wherein said frame includes a base plate which has means for tempering.
- 9. The apparatus as claimed in claim 8, wherein said base plate has at least one integrated temperature sensor, and at least one integrated heating element which are connected to a control device by means of lines.
- 10. The apparatus as claimed in claim 7, wherein said heating element of said rotary punch is an electrically operated heating cartridge.
- 11. The apparatus as claimed in claim 10, wherein said heating cartridge is coaxially arranged in the rotating cutting tool.
- 12. The apparatus as claimed in claim 7, wherein said heating element of said opposing tool is an electrically operated heating cartridge.
- 13. The apparatus as claimed in claim 12, wherein said heating cartridge is coaxially arranged in the rotating opposing tool.
- 14. The apparatus as claimed in claim 7, wherein said integrated temperature sensor of said cutting tool is arranged near to the working outer shell of the cutting tool.
- 15. The apparatus as claimed in claim 7, wherein said integrated temperature sensor of said opposing tool is arranged near to the working outer shell of the opposing tool.
- 16. The apparatus as claimed in claim 7 wherein a slip-ringless, wear-free operating connecting element is connected in lines between the rotating cutting tool on the one hand and a control device on the other hand.
- 17. The apparatus as claimed in claim 7 wherein a slip-ringless, wear-free operating connecting element is connected in lines between the rotating opposing tool on a one hand and the control device on the other hand.
- 18. The apparatus as claimed in claim 7, wherein said frame has means for tempering.
- 19. The apparatus as claimed in claim 18, wherein each side portion of the frame has at least one heating element and at least one integrated temperature sensor which are connected to a control device by means of lines.
- 20. The apparatus as claimed in claim 7, wherein said frame has an upper bridge which has means for tempering.
- 21. The apparatus as claimed in claim 20, wherein said upper bridge of the frame has at least one integrated heating element and at least one integrated temperature sensor which are connected to a control device by means of lines.
- 22. A method of maintaining constant a set of cutting conditions at a rotary punch for producing profiled and straight cuts on moving webs or flat individual articles of foil or paper particularly for manufacturing hygiene products, envelopes, flat bags or the like, by means of a rotating cutting tool having a longitudinal bore and a fixed or rotating opposing tool having a longitudinal bore which are arranged within a frame, wherein a cutting edge or edges on the cutting tool describe a cylindrical envelope and hit the opposing tool at the instant of the cut and wherein under operating conditions a rotary punch operating temperature dependent on the product and on the environment results, said method comprising
- monitoring and controlling the heating of the rotary punch by thermal conduction to an adjustable and predeterminable constant temperature, by means of heat sources, coaxially disposed in said longitudinal bore of said cutting tool, said constant temperature being no less than the rotary punch operating temperature which results under operating conditions;
- adjusting the space of the cylindrical envelope described between the cutting tool and the opposing tool so as to set the cutting conditions thereof;
- maintaining the rotary punch at said temperature;
- wherein the opposing tool is heated and the heating of the cutting tool and the opposing tool is by means of integrated heating elements coaxially disposed in said longitudinal bores, and the temperature is monitored by means of integrated heat sensors; and
- wherein the temperature is controlled by a common, stationary control device which is connected with all the heating elements and temperature sensors, wherein said rotating cutting tool has a working outer periphery and said opposing tool has a working outer periphery; Wherein said cutting edge or edges are on said working outer periphery of said cutting tool; and monitoring the temperature of the cutting tool and the opposing tool by said integrated heat sensors in bores near to said working outer periphery of said cutting and opposing tools.
- 23. Apparatus for maintaining constant a set of cutting conditions at a rotary punch for producing profiled and straight cuts on moving webs or flat individual articles of foil or paper, particularly for manufacturing hygiene products, envelopes, flat bags or the like, by means of a rotating cutting tool having a longitudinal bore and a working outer periphery and a fixed or rotating opposing tool having a longitudinal bore which are arranged within a frame, wherein a cutting edge or edges on the cutting tool describe a cylindrical envelope and hit the opposing tool at the instant of the cut and wherein under operating conditions a rotary punch operating temperature dependent on the product and the environment results, said apparatus comprising
- an integrated heating element coaxially disposed in said longitudinal bore of said cutting tool and an integrated temperature sensor included in said rotary punch;
- an integrated heating element coaxially disposed in said longitudinal bore of said opposing tool and an integrated temperature sensor included in said opposing tool for tempering so as to maintain constant and set the spacing of the cylindrical envelope described by the cutting edge or edges from the opposing tool;
- said tempering resulting in a temperature of said rotary punch which is no less than the rotary punch operating temperature which results under operating conditions; and
- means for adjusting the spacing of the cylindrical envelope described by the cutting edge or edges from the opposing tool so as to set the cutting conditions thereof subsequent to the tempering of the rotary tool and opposing tool, wherein said rotating cutting tool has a working outer periphery and said opposing tool has a working outer periphery; wherein said cutting edge or edges are on said working outer periphery of said cutting tool; and said integrated temperature sensors are located in bores near to said working outer periphery of said cutting tool and said opposing tool for monitoring the temperature of said cutting tool and said opposing too.
Priority Claims (1)
| Number |
Date |
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| 3730392 |
Sep 1987 |
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Parent Case Info
This is a continuation of application Ser. No. 239,693, filed Sept. 2, 1988, for "METHOD AND APPARATUS FOR MAINTAINING THE CUTTING CONDITIONS OF A ROTARY PUNCH CONSTANT", now abandoned.
The present invention relates to a method and apparatus for maintaining the cutting conditions constant of a rotary punch for producing profiled and straight cuts on moving webs or flat individual articles of foil or paper, particularly for manufacturing hygiene products, envelopes, flat bags or the like. The rotating cutting tool and a fixed or rotating opposing tool are arranged within a frame wherein the cutting edge or edges describe a cylindrical envelope and hit the opposing tool at the instant of the cut. The operating conditions of the rotary punch are such that an operating temperature dependent on the product and the environment is adopted.
Rotary punches of the above described type are well known. They are used widely, e.g., in the processing of paper and foils and in the manufacture of hygiene products, such as panty liners, sanitary napkins and the like. Their main members, the rotating cutting tool and the opposing tool, are arranged tangential to a working plane within a frame which comprises substantially a lower base plate, left and right side portions and an upper bridge. The cutting tool is generally cylindrically shaped and is provided with lateral bearing pegs by means of which it is mounted in roller bearing units. With the aid of these roller bearing units it is slidably received in the side portions of the frame and positioned and adjusted with a predetermined force with respect to the opposing tool. Either a stationary bar or a rotating roller may serve as the opposing tool. A stationary opposing tool is generally secured with a tool holder to the base plate while a rotating opposing tool, as in the case of the rotating cutting tool, is mounted in roller bearing units by means of which it is positionally fixedly received in the side portions of the frame.
Rotary punches of this type generally operate satisfactorily under normal temperature conditions. However, problems arise if precision cuts are to be performed under varying temperature conditions. In this connection it is immaterial whether these temperature conditions are caused by the processing of hot products or by varying ambient temperatures. Because of the disparate construction of the punching device by the use of different construction materials and different mass attachments, and because of the localized heat source, different and varied temperatures result within the punch device. Different temperatures and also different construction materials cause different thermal expansions in the rotary punch. Depending on the location of the warming, this results within the rotary punch to cutting failures or to the cutting and opposing tools hammering against one another thus resulting in increased wear of the tools and the necessity for frequent adjustment of the tool. This results finally in a considerable shorter service life of the tool. This is particularly serious if, when processing hot products, the cutting tool and the opposing tool are warmed faster and higher than the remaining parts of the rotary punch.
Various attempts have previously been made to solve this problem with rotary punches. One such attempt utilizes Schmitz rings, which are known from printing machine technology, to support the rotating cutting tool against the rotating opposing tool. The Schmitz rings have the principle object of preventing compensating movements between the cutting and opposing tools, as are caused by varying cutting and imbalance forces, and also to avoid incorrect settings of the cutting tool with respect to the opposing tool which result due to the action of heat and lead to the destruction of the cutting and opposing tools.
Such a rotary punch is disclosed in German Pat. document No. DE-GM-6602393. The punch therein serves to punch labels from adhesive paper. The cut may only be effected through the label paper into the adhesive layer and under no circumstances through the carrier paper. In order to ensure that this is the case, the diameter of the Schmitz rings in this construction are so selected that a free spacing of the thickness of the carrier paper is maintained between the effective cutting edge and the opposing roller.
Rotary punches equipped with Schmitz rings fulfill the duties required of them but only if one accepts considerable disadvantages. The most serious of these is that the axial spacing between the knife roller and opposing roller matching the inevitable wear of the knife can only be compensated for by complicated and time consuming grinding of the entire knife roller including the Schmitz rings. A substantial disadvantage of the Schmitz rings is that the opposing roller must be constructed as a rotating roller which rotates with the same peripheral velocity as the knife roller whereas it is often necessary for the best cutting results to stop the opposing roller or at least permit it to rotate slower than the knife roller. A factor weighing against the use of Schmitz rings is the effect of the considerable amount of dust which is produced when cutting paper. This dust is thermally deposited on the Schmitz rings and forces the cutting and opposing rollers apart, whereby not only the cutting action but also the service life of the bearings is unfavorably influenced.
In U.S. Pat. No. 3,186,275, to Obenshain, granted June 1, 1965, it is proposed that the lateral frame portions of a transverse cutter be warmed. For this purpose heating elements and temperature sensors, which are connected to a control device, are mounted on the lateral frame portions. Before the commencement of production, the temperature of the lateral frame portions in this transverse cutter are increased to approximately the temperature which obtains under production conditions due to the heating of the bearings. This results in the cutting conditions, when starting up after a long period of inactivity, being approximately the same as during normal production operation. Apart from the fact that roller bearing units are now available in which the problem referred to in the Obenshain patent does not arise, it is not possible with this pure transverse cutting device to perform shaped cuts on hot products. It is assumed in this patent that the cutting and opposing tools are not significantly warmed during operation and that only the cutting conditions when starting up after a long period of inactivity are to be improved. The described heating device thus has virtually no purpose after commencement of production. The transverse cutting device also has no facility either for determining the temperature on the cutting and opposing tools or for influencing them.
It is, therefore, the object of the present invention to provide a method, and apparatus suitable for carrying out the method, which permits the cutting conditions of a rotary punch to be maintained constant even at changing and differing temperatures and improving the service lives of the tools.
The above object is accomplished in accordance with the present invention by providing a method and apparatus for a rotary punch which produces profiled and straight cuts on moving webs or flat individual articles of foil or paper wherein the punching device is brought completely to a constant temperature, which is above the highest operating temperature which obtains under operating conditions, and is maintained at that temperature. The apparatus for accomplishing this method includes tempering means for the rotary punch so as to maintain constant and set the spacing of the cylindrical envelope described by the cutting edges of the cutting tool from the opposing tool. As a result of this feature the negative influence of the unchecked thermal expansion is eliminated and thus the tool service life, the operational reliability and finally also the ease of service are substantially increased.
An unexpected further advantage resulting from the present invention is that by means of the controlled, individual temperature increase at the cutting and opposing tools, a sensitive adjustment in response to wear which enhances the service life of the tool is possible.
Other objects and features of the present invention will become apparent from the following detailed description considered in connection with the accompanying drawings. It is to be understood, however, that the drawings are designed as an illustration only and not as a definition of the limits of the invention.
US Referenced Citations (10)
Continuations (1)
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239693 |
Sep 1988 |
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Patent Grant
5022295
