There is provided a method and apparatus for maintaining the cutting conditions constant at a rotary punch by bringing the rotary punch to a constant, predetermined temperature and maintaining the rotary punch at that temperature. Tempering elements are included in the rotary punch so as to maintain constant and set the spacing of the cylindrical envelope described by the cutting edge or edges from the opposing tool.
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.
The shredding device for paper web according to the present invention is equipped with a receiving drum, the peripheral surface thereof being formed as a suction surface, a drum shaft which is arranged in parallel to the receiving drum, a bladed drum which is mounted on the drum shaft, a pair of free rollers which are rotatably mounted via bearings on the drum shaft at both sides of the bladed drum and which have a larger diameters than the bladed drum, a pair of rocking arms which are free to rock and which support both ends of the drum shaft, a pair of air cylinders which urge these rocking arms toward the receiving drum, and a control system which increases the air pressure of the air cylinders according to the thermal expansion of the free rollers and displaces the axes of the free rollers with respect to the axis of the drum shaft through the bearings.
A direct temperature sensing tool directly senses and provides feedback of the temperature of its cutting environment. The tool comprises a base body defining at least one cutting edge of the tool. A protective coating surrounds the base body and the cutting edge, the protective coating providing a friction-reducing surface for the tool. A thin film temperature sensing device, such as a thermocouple device, is disposed on the base body at a distance from the cutting edge. The temperature sensing device is encapsulated within the protective coating. An electrical connection is defined through the protective coating in electrical communication with the temperature sensing device. The tool is configurable with a machine tool so that the temperature sensing device is in communication with a conversion device of the machine tool for providing an indication of the temperature sensed by the temperature sensing device.
A rotary die cutter in accordance with the present invention has frames 1 for rotatably supporting a die cut cylinder 20 and an anvil cylinder 21 via a bearing 22, and is configured so that oil is circulated in the die cut cylinder 20 and/or the anvil cylinder 21. Also, another rotary die cutter in accordance with the present invention has frames 20 for rotatably supporting a die cut cylinder 3 and an anvil cylinder 4 via a bearing 21, and is configured so that a cooled lubricating oil 23 is supplied to the bearing 21.
Invention discloses a heated die to form long lived aperatures in upper region of plastic wrapped packages; said die featuring improved construction providing focused unidirectional heat flow to avoid package failure leading to product deterioration and package failure and disengagement with display hangers; said heat control effected by micro control of flow of energizing electricity.
A contact cleaning roller (CCR) system includes a shell having an electrostatically active outer surface and being supported by a close-fitting rotatable shaft. The shaft within the shell is provided with a cam groove extending from a first axial location to a second axial location disposed 180.degree. from the first axial location, and then back to the first axial location. A cam follower attached to the inner surface of the shell rides in the cam groove, causing the shell to oscillate axially of the shaft at a frequency of oscillation which is the numerical difference between the rotational frequencies of the shell and shaft. In a preferred embodiment, the CCR shell is nipped against a backing roller, which may be an idle roller or a driven roller, the web passing therebetween in contact with the working surfaces of both rollers. Outboard of the working surfaces, the shaft of the backing roller has a first drive roller having a first diameter, and the shaft of the barrel cam has a second drive roller nipped against the first drive roller and having a second diameter slightly different from the first diameter. Thus, the CCR shell turns at a rotational frequency imposed by the linear velocity of the web whereas the CCR shaft turns at a different frequency as imposed by the relative diameters of the two speed-controlling drive surfaces, the frequency differential being equal to the oscillation frequency of the CCR shell along the barrel cam.
