EP0386500A1 - Exchangeable cassette for a manual apparatus for transferring a film from its backing strip to a support - Google Patents

Abstract

In an exhangeable cassette for a manual apparatus for transferring a film from its backing strip (11) to a support, which contains a supply reel (8) with a backing strip (11) coated with the film, and a winding reel (9), and the backing strip (11) is led from the supply reel (8) to the winding reel (9) via an application element (14) protruding from the cassette (2), this reel (9) being provided with a backstop (17), the supply reel (8) is assigned a retarding device (20, 21, 22), which is active in the unwinding direction of said reel. In this case, the retarding device is so designed that the retarding moment exerted by it on the supply reel (8) decreases, at least after an initial number of rotations of the supply reel (8), with an increasing, further number of rotations by the supply reel (8) until the strip supplier (12) is completely unwound from the supply reel (8). <IMAGE>

Description

The invention relates to an interchangeable cassette for a hand-held device for transferring a film from a carrier tape to a substrate, which contains a supply reel with a carrier tape coated with the film and a take-up reel, and the carrier tape from the supply reel via an application element protruding from the cassette led back to the take-up spool and this is provided with a backstop.

Such exchangeable cassettes (disposable cassettes) are inserted into the hand-held device, the supply reel and the take-up reel being coupled to one another by means of suitable form-fitting plug-in connections and a transmission integrated in the hand-held device with an interposed slip clutch for maintaining the required belt tension during the insertion process. These interchangeable cassettes with associated handheld devices have been manufactured and sold for some time and are e.g. B. described in German patent application P 37 36 357.3-27.

In this known interchangeable cassette, the carrier tape is guided in such a way that, if the film on the carrier tape consists of an adhesive coating, the empty tape (i.e. carrier tape without adhesive) returning from the application element into the cassette before it enters the take-up reel on the (from the adhesive film existing) outer surface of the take-up reel comes to the plant and adheres to the adhesive of the supply reel. If the carrier tape is now all However, not with an adhesive coating, but with a coating with low adhesive force (for example in the case of cover-up tapes with a cover coating), the disadvantage arises that, although the tape was mounted in the cassette in a tensioned state between the two reels , a loosening of the tightened tape guide can occur until the cassette is inserted into the hand-held device, e.g. B. during the packaging of the cassette, during the transport of the cassette to the consumer or during the time when a cassette is outside the device, for example, when using a cassette with different types of coating or bandwidth and a cassette temporarily removed from the device and temporarily stored because another cassette is about to be used.

In order to achieve an optimal take-off behavior of the tape, it has proven to be expedient in such drives that the rotational speed difference between the drive and take-up reel compensated for by the slip clutch towards the end of the tape pass (i.e. when there is only a small remaining supply of coated carrier tape on the supply take-up reel is present and accordingly a relatively high drive speed of the supply reel with the emptying tape supply is opposed to a relatively low output speed of the take-up reel with the filling reel). In order to achieve this, only a minimal slippage can be provided for the start-up (ie in the initial area of using a new cassette), which in particular with a cassette whose carrier tape could loosen in the meantime has the very undesirable effect that the low Initial pull is necessary because of an undesirably long unwinding or film transfer path in order to tighten the tape again in a functional manner. In this phase, a loop formation can easily occur on the application element, which on the one hand makes it difficult, if not impossible, to precisely position the cover surface on the substrate and, on the other hand, can even lead to a tape tear, namely if the loop is on the side of the application element slips because the guide and guide elements are not in a loosened band can be more effective. However, this problem becomes less and less urgent with increasing consumption of carrier tape and finally resolves itself if, with increasing tape consumption (i.e. increasing unwinding length of the tape from the supply reel), the slip in the slip clutch becomes larger and finally large enough to almost make the tape to tighten immediately or only on a very small unwinding section, because the speed difference between the two coils is sufficiently large.

To the problem of unwanted relaxation of the tape z. B. to solve during transport or storage of the cassette, it is known, for example, with ribbon cassette for printers or typewriters to insert cardboard strips angled on both sides into the coupling inner profiles of the two coil cores of the two cassette coils so as to cause a rotation and loosening movement triggered by vibrations to prevent. However, tape loosening can also occur here, namely if the cassette is not inserted into the device immediately after removing the security strip or if, as already described above, the cassette is briefly changed and temporarily stored cassettes are no longer provided with the security strip because this is usually not stored, but is thrown away when the new cassette is inserted into the machine.

If not for cassettes for handheld devices of the type mentioned at the outset, it is nevertheless known for ribbon cassettes for printers and typewriters to use spring tongues integrated into the lower and / or upper part of the cassette, which continuously brake the entire rolling cycle of the cassette Exercise the core of the supply spool. Here, however, there is the effect that, starting from a required minimum starting braking torque, the braking effect of the supply reel increases with an increasing number of revolutions, that is to say in an unwinding phase in which, due to the subsequent slippage that is hardly necessary, braking is no longer necessary, an undesirable occurs high braking resistance, which is reflected in Adversely, the systemic increase in rolling resistance due to the decrease in the supply roll diameter is added, which ultimately leads to an unacceptable sluggishness towards the end of the ribbon supply, which is why such a solution is acceptable for ribbon cartridges for mechanical devices in which the reel drive is done mechanically , but not for hand-held devices in which the unwinding force has to be applied by the operator himself and with an increasing unwinding distance an ever greater operator force would be required.

Proceeding from this, the object of the invention is to develop an exchangeable cassette (disposable cassette) for a hand-held device for transferring a film from a carrier tape to a substrate of the type mentioned at the outset in such a way that the unwanted occurrence of tape loosening, in particular, is simple, inexpensive and easy to assemble when using a new, only little used cassette, is effectively avoided, even if the cassette is not inserted into a device, and at the same time a stiffness which does not hinder use occurs during the further use of the cassette.

According to the invention, this is achieved in an exchangeable cassette of the type mentioned at the outset in that the supply reel is assigned a braking device which is effective in its unwinding direction and whose braking torque acting on the supply reel is at least after an initial, very small number of revolutions of the supply reel (“inlet” or "Grinding phase" of the device) decreases with increasing number of revolutions of the supply reel up to the complete processing of the tape supply.

The change cassette according to the invention initially has a remarkably simple structure and is no more complicated to assemble than the already known, commercially available cassettes. Effective braking of the supply roll is achieved, particularly in the area of the initial use phase with a new cassette, in which the speed difference to be compensated for in the slip clutch is only relatively small, but reliably prevents any occurrence of undesired loosening of the belt guide. The fact that, according to the invention, the braking torque of the braking device also decreases continuously over the course of the period of use (ie with an increasing number of unwinding revolutions of the unwinding reel) until the tape supply has been completely unwound, but it is ensured that the otherwise difficult stiffness associated with the use of the hand-held device with such an inserted cassette significantly hindered, if not impossible, would not occur at all. Because the measures according to the invention do not otherwise require any changes to the outer dimensions of the cassette, the additional advantage is also achieved that the exchangeable cassettes according to the invention can also be inserted into the handheld devices already supplied in place of the previous exchangeable units with unchanged functionality, so that even old devices with such new exchangeable cassettes can be populated without any additional changes. In addition, the insertion of the cassette and the entire "cassette handling" are not associated with any special requirements or require any additional manipulation in comparison to conventional exchangeable cassettes, so that no irritation of the user can occur.

Particularly preferably, in the interchangeable cassette according to the invention, the braking device is designed so that it has a brake member designed as a wearing part, which is in positive engagement with counter-elements movable relative to it when the supply spool is rotated to generate the braking torque, and in such a way that the frictional engagement increases with increasing Wear of the brake member designed as a wear part is continuously reduced. Advantageously, the brake member designed as a wearing part consists of a roof-shaped transverse rib made of plastic attached to the free end of a resilient tongue, which meshes with an annularly closed row of a plurality of locking knobs lying on a circular path. As a result, a particularly simple and easy to manufacture structure of the Interchangeable cassette according to the invention created, with the interaction of the roof-shaped transverse rib made of plastic with a large number of locking nubs forming a closed circumferential row per revolution of the supply spool, such a large number of locking interventions always form-fittingly newly formed and then canceled again that the many nubs are relative soon on the cross rib meshing with them, on which they only attack their width over a certain sub-area, cause signs of wear in the form of increasingly larger outbreaks. However, the more pronounced these signs of wear and tear and the deeper the removal troughs caused by the intermeshing knobs on the transverse rib, the smaller the braking torque which can then be transmitted between the transverse rib and locking knobs when turning the supply spool. Ultimately, this can lead to the fact that towards the end of the tape supply the knobs have "milled" a recess into the transverse rib that essentially corresponds to their shape, so that no appreciable braking torque then occurs at all.

All materials suitable for the purpose mentioned can be used as the material for the wear member, which, in cooperation with a large number of locking knobs, lead to the occurrence of corresponding local wear on the transverse rib in the area of the locking engagement relatively early. However, an impact-resistant polystyrene, for example a styrene-butadiene copolymer, is particularly preferably used for this purpose, as is also used as a medium-impact-resistant type for the production of injection-molded parts with low mechanical impact for low mechanical impact and shock loads (such a plastic is commercially available under the Description "Vestyron 512" available). It is not even necessary that the wear-resistant cross rib is made of a different material than the locking cams that mesh with it, since even if both elements are formed from the same material as a result of the many locking interventions per revolution of the supply spool in any case on the cross rib significantly greater wear than occurs on the individual cam. Of course, the locking knobs can also be made of a more wear-resistant material, such as metal, if this is desirable in individual cases despite the higher costs and the more difficult assembly and any wear on the locking knobs should be avoided as completely as possible. However, the design of the knobs and the transverse rib made of the same plastic should be sufficient for most applications and also offers the advantage of being inexpensive and easy to manufacture.

The locking knobs can be designed in any suitable shape, but they are particularly preferably provided in the form of conical tips, as a result of which a good locking effect can be achieved on the roof-shaped transverse rib with a planned wear effect.

A particularly preferred embodiment of the interchangeable cassette according to the invention also consists in that the spring tongue is provided on a cassette side wall and the locking knobs are provided on a flanged disk which is arranged next to this cassette side wall and is concentrically connected to the supply reel. Here, the locking knobs are radially in the form of a plurality of knobs which are evenly distributed on a pitch circle of the coil core of the supply reel and which mesh with the transverse rib on the spring tongue, the spring tongue elastically springing out as a locking knob passes and thus frees the passage for the locking knobs.

In a preferred development of the interchangeable cassette according to the invention, the transverse rib is formed in one piece with the resilient tongue carrying it (preferably as part of a cassette side wall), so that an easily producible, well-effective and yet simple plastic part is produced.

Furthermore, the cross-section of each rib is preferably provided in a substantially triangular shape in the interchangeable cassette according to the invention, with - again preferred - this cross-section at its tip of the transverse rib projecting from the resilient tongue having an opening angle of at least 30 ^o and at most 60 ^o , particularly preferably of 45 ^o trains. Only the tip of the cross rib itself is slight rounded off, which results for manufacturing reasons. At angles greater than 60 ^o , the wear that occurs later is generally too low for the desired effect; at angles less than 30 ^{o there} is considerable wear, but the initial braking torque values become too small. For most applications, an angle of around 45 ^{o should} offer an optimization of the braking torque value and wear

It is also very particularly preferred if the locking knobs are arranged in the center of the transverse rib, so that the desired wear also occurs approximately in the center of the transverse rib.

A further preferred embodiment of the interchangeable cassette according to the invention also results if not only one but two resilient tongues are provided, which are offset from one another with respect to the annularly closed row of locking knobs by 180 ^{o and} each have a transverse rib. In certain cases, it may even be advantageous if three or four spring tongues, each offset with a cross rib and uniformly offset over the circumference of the circle formed by the locking knobs, are used, but in most cases the use of one or two with a cross rib is already used provided spring tongues is sufficient.

• Fig. 1 ein Handgerät mit einer eingelegten erfindungsgemäßen Wechsel­kassette in Prinzipdarstellung (in geöffnetem Zustand);
• Fig. 2 die Prinzipdarstellung einer erfindungsgemäßen Wechselkassette, bei der eine Kassetten-Seitenwand entfernt und der Wickelvorrat auf der Aufwickelspule zur Darstellung einer Federzunge in der (gezeigten) Seitenwand teilweise unterbrochen ist;
• Fig. 3 den Schnitt längs III-III aus Fig. 2;
• Fig. 4 eine Prinzipdarstellung der kreisförmigen Anordnung von Rast­noppen an der Bordscheibe einer Aufwickelspule;
• Fig. 5 die Perspektivdarstellung einer (noch nicht benutzten) Federzunge mit einer Verschleiß-Querrippe (in stark vergrößerter Darstellung);
• Fig. 6 die Darstellung aus Fig. 5, jedoch nach einiger Einsatzdauer und nach Auftreten eines deutlichen Verschleißes an der Querrippe;
• Fig. 7 eine Diagrammdarstellung gemessener Bremsmoment-Verläufe ver­schiedener Kassetten über der Umdrehungsanzahl der Vorratsspule (mit Angabe des Endverschleißes) sowie
• Fig. 8 eine Diagrammdarstellung gemessener Band-Abzugskräfte der Gesamteinheit Handgerät/erfindungsgemäße Kassette, die der Benutzer bei Gebrauch des Gerätes aufbringen muß, über der Abwickeldrehzahl der Vorratsspule.

The invention is explained in more detail below in principle by way of example with reference to the drawing. Show it:

• 1 shows a hand-held device with an interchangeable cassette according to the invention inserted in a schematic diagram (in the open state);
• 2 shows the basic illustration of an interchangeable cassette according to the invention, in which a cassette side wall is removed and the winding supply on the take-up spool is partially interrupted to show a spring tongue in the side wall (shown);
• Fig. 3 shows the section along III-III of Fig. 2;
• Figure 4 is a schematic diagram of the circular arrangement of locking knobs on the flanged disc of a take-up spool.
• 5 shows the perspective representation of a spring tongue (not yet used) with a wear transverse rib (in a greatly enlarged representation);
• FIG. 6 shows the illustration from FIG. 5, but after a period of use and after significant wear has occurred on the transverse rib;
• Fig. 7 is a diagram of measured braking torque curves of various cassettes over the number of revolutions of the supply reel (with indication of the end wear) and
• 8 shows a diagram of measured tape pull-off forces of the entire unit of the hand-held device / cassette according to the invention, which the user must apply when using the device, over the unwinding speed of the supply reel.

In Fig. 1, a hand-held device for transferring a film from a carrier tape to a substrate is shown, which has a gear plate 1, an interchangeable cassette 2 and a swivel cover 3 which is pivotally attached to the gear plate 1 via a pivot pin 4.

The interchangeable cassette 2 is inserted into a recess 5 in the transmission plate 1, a supply spool 8 (FIG. 2) provided in the interchangeable cassette 2 (FIG. 2) and a take-up reel 9 likewise arranged in the interchangeable cassette 2 can be rotatably attached to the rotating bolt 6 . In this case, any design of pivot pins and coils suitable for a rotationally locking attachment can be used. A particularly suitable form is shown for example in Fig. 2 in connection with the supply spool 8: there protrude from the spool core radially inward projecting a few driver knobs 10 which are inserted into corresponding slot receptacles on the associated pivot pin 6 when inserting the exchangeable cassette 2, so that the Coil 8 in Direction of rotation is positively coupled to the supply spool 6. The same measures can also z. B. for the spool core of the take-up spool 9 and the associated pivot pin 7, but are not shown in the figures.

The gear plate 1 covers a gear that connects the pivot pin 6 (as the drive pin) with the pivot pin 7 (as the output pin) with the interposition of a slip clutch. This gear ensures that when the supply reel 8 is unwound, a corresponding drive is transmitted to the take-up spool 9 via the rotation of the pivot pin 6 which is triggered, in such a way that the guidance of the carrier tape 11 between the supply spool 8 and take-up spool 9 is always kept taut . The occurring speed differences between the supply reel 8, the winding diameter of which continuously decreases, and the take-up reel 9, the winding diameter of which is always increasing, are compensated for by the slip clutch (not shown in the figures) within the transmission.

On the supply reel 8 there is a winding supply 12 on the carrier tape 11, which with a film, for. B. a cover film (cover-up film) is coated. From the illustration according to FIG. 2, in which an interchangeable cassette 2 is shown with a removed side wall to show the internal conditions of the cassette, it can also be seen that a resilient support leg 13 is arranged in the interchangeable cassette 2, which has one end at which an application bar 14 is attached, protrudes from the cassette 2.

The carrier tape 11 running from the winding supply 12 of the supply reel 8 is first led to this application bar 14, deflected at it, fed back into the cassette 2 and passed on to the take-up reel 9 via an intermediate spring tensioner 15.

2, in which one (upper) side wall of the exchangeable cassette 2 is removed, the other (lower) side wall 16 can be seen, in which a spring tongue 17 is formed, which in a (in Fig. 2 hidden and therefore not shown) toothing engages on the end of the take-up spool 9 facing this side wall 16. The shape of the tooth flanks and the end of the spring tongue 17 is selected so that the winding spool 9 can be freely rotated in the winding direction (see arrow in FIG. 2) by the transmission gear, but is locked in the opposite direction of rotation. As a result, a backstop is formed, which prevents the take-up spool 9 from unwanted unwinding.

The side wall 16 of the exchangeable cassette 2 is fastened to the side wall (not shown in FIG. 2, removed) with the interposition of spacer bolts 18 in a suitable manner.

In the side wall 16 of the interchangeable cassette 2, two further, resilient tongues 20 are formed, which are shown in FIGS. 5 and 6 in an enlarged perspective view. As can be clearly seen in particular from these figures, the resilient tongues 20 are provided in the region of their free end with roof-shaped transverse ribs 21 which have a triangular cross section and converge at their angle projecting from the spring tongue 20 at an angle α which is not less than 30 ^o and not greater than 60 ^o , preferably 45 ^o .

From Fig. 3, which shows a section along line III-III of Fig. 2, it can be seen that the supply spool 8 is provided at its end facing the side wall 16 of the exchangeable cassette 2 with a radially projecting flanged disc 23 against which the winding supply 12 lies on the coated carrier tape on this side.

4 shows a view of the take-up spool 8 from the side of the flanged disk 23, from which it can be seen that a circumferential row of projecting locking knobs 22, which is arranged concentrically to the central axis thereof, is formed on the flanged disk 23 and, as shown in FIG. 3, protrude from the flanged disk 23 in the direction of the side wall 16 of the exchangeable cassette 2. As can also be seen from FIG. 3, the transverse channel 21 of the spring tongues 20 projects into one another between the two following locking knobs 22 formed space, so that the locking knobs 22 run continuously against the inclined side walls of the transverse trough 21 when the supply spool 8 is rotated and, when the rotary tongue 21 is rotated further, press the resilient tongue 21 outward until the respective locking knobs 22 can pass under the transverse trough 21. Subsequently, the spring tongue 20 immediately springs back in, whereby the transverse rib 21 engages in the space between the just passed through and the next locking knob 22. In this way, a plurality of rebound and spring-in movements of the spring tongues 20 are forced by the locking knobs 22 during one revolution of the carrier disk 23 and a corresponding braking torque is exerted on the carrier disk 23.

In the exemplary embodiment shown, the locking knobs 22 are designed as small truncated cones and are oriented such that they contact the total width of the transverse channel 21 in the central region when it passes by

The transverse groove 21 is made in one piece with the resilient tongue 20 as part of the side wall 16 from a semi-impact resistant polystyrene, as is available on the market under the trade name "Vestyron 512". This plastic has a dielectric strength (according to DIN 53481)> 50kV / mm, a limit bending stress (according to DIN 53452, standard rod 2) of 600kp / cm², a modulus of elasticity (according to DIN 53457 - from tensile tests according to DIN 53455) of 28,000kp / cm² as well as a notched impact strength (Charpy impact test according to DIN 53453, standard rod according to Fig. 2, at +20 ^o C) of 4cmkp / cm².

Due to the constant interaction with the locking knobs 22, the transverse ribs 21 are subjected to ongoing mechanical stress, which, due to the suitably chosen plastic material for the transverse ribs, leads to increasingly greater signs of wear 24 occurring there in the place of the interaction with the locking knobs. Fig. 5 shows a resilient tongue 20 with a still undamaged cross rib 21, that is still in the state before the first use of the Cassette, while Fig. 6 shows the same spring tongue and cross rib after a long period of use (with only a small amount of winding 12 on the supply reel 8). Here, a clear, wear-related recess 24 in the form of an irregular groove with a depth T can be seen on the transverse rib 21. This furrow 24 was introduced into the transverse rib 21 by the large number of locking knobs 22 passing by during the period of use of the cassette.

Due to the wear-induced groove 24, the frictional connection between the locking knobs 22 and the spring tongue 20 (via the transverse rib 21) is now smaller, in particular the spring travel of the spring tongue as the locking knobs 22 pass by the size of the depth T of the groove 24 is smaller than In the undamaged state of the transverse rib 21, what ultimately reduces the braking force generated between the spring tongue 20 or transverse rib 21 and flanged disk 23 accordingly. Should the groove depth T of the wear groove 24 ultimately become so large that it corresponds to the overlap between the transverse rib 21 (in the rest state of the spring tongue 20) and the locking knobs 22, this would mean that the locking knobs 22 are essentially unhindered by the groove 24 could run through and past the transverse rib 21, so that finally no braking torque would be transmitted.

The choice of the cross-sectional shape of the transverse rib 21 and the shape of the locking knobs 22 meshing with it, in particular by the choice of the angle of attack α between the two side surfaces delimiting the transverse rib 21 and the height of the initial coverage of the locking knobs 22 and the transverse rib 21, and also by the Selection of the material for the transverse rib 21 can be influenced in accordance with its intended wear behavior so that the braking torque exerted on the supply reel 8 shows the desired course depending on the unwinding path of the coated carrier tape 11, i. H. descends in the desired manner.

The direction of the relative movement between locking knobs 22 and Transverse ribs 21 run perpendicular to the free end edge 25 of the transverse ribs 21 in order to transmit forces to the spring tongues 20 as far as possible only when the transverse tongues 21 and locking knobs 22 meet, and to keep them as largely as possible free of lateral deflection forces. With increasing, abrasion-related groove on the transverse ribs 21, however, the occurrence of forces acting laterally on the resilient tongues 20 can no longer be prevented, which is why each spring tongue 20 should be made as rigid as possible in the direction of the extension of the transverse ribs 21, so that at least no lateral deflections when Occur passing the locking knobs 22.

The supply reel 8 as well as the flanged wheel 23 and the locking knobs 22 arranged thereon are preferably formed in one piece, wherein the same plastic as that used for the spring tongue 20 and transverse rib 21 can be used for them. Because the fact that each transverse rib 21 meshes with a large number of locking knobs 22 during one revolution of the flanged disk 23 has the effect that in any case wear occurring at the end edge 25 of the transverse rib 21 is relatively much greater than that on the intermeshing knobs 22 detectable wear, so that the latter is essentially irrelevant to the former.

In Fig. 7 the course of the measured braking torque M _D over the number of unwinding revolutions n of the supply reel 8 for different configurations of the interchangeable cassette and in Fig. 8 the measured course of the tape pulling forces P of the entire unit, which consists of the handheld device with an interchangeable cassette , ie the effort that the user must exert when using such a device, is also shown over the number of unwinding revolutions of the supply reel 8.

The supply spools used for the measured values of FIGS. 7 and 8 resulted in a complete consumption of the carrier tape of a supply reel in the course of 130 unwinding revolutions, with only the pure braking torque M _D being unaffected by overall efficiencies mechanics handheld device / exchangeable cassette was measured in order to achieve the most accurate possible analysis of the desired effect.

In Fig. 7 curve 1 first shows the braking torque curve as it results when spring tongue is pressed axially against a flat end face of the coil core of a supply coil, the spring tongues coming into flat contact with this surface and the braking torque alone is expanded by the friction of the spring tongues pressed elastically against the coil core. The measurements were carried out (as with all other measurements shown in diagrams 7 and 8) only from the second turn of the supply reel 8, in order to take into account the winding of the leader tape, which is basically fast-forwarded by the operator during cassette assembly, while in the case of However, the consideration to be taken here is only interesting as to what the user feels afterwards, namely when using the hand-held device to transfer a film. It is not surprising that in this embodiment the braking torque does not remain constant, but rather increases almost over the entire unwinding distance, undesirably, especially at the beginning where braking is required, the lowest values for the braking torque and later, where additional Braking resistors undesirable, if not harmful, set the maximum braking torque values.

Curves II, III and IV, which were created with an interchangeable cassette of the type according to the invention with targeted wear, on the other hand show the desired drop in braking torque with increasing tape consumption. These curves also initially show a certain increase in the braking torque (but only in a small initial range, which is between 10 and about 30 revolutions of the supply reel 8): this is an increase caused by the grinding in of the entire mechanism of the cassette occurs initially, but is of insignificant importance with regard to the desired overall behavior of the torque in this unwinding phase of the supply belt and compared to the important, occurring afterwards and which can be ascertained until the complete winding supply 12 has been completely processed, ongoing decrease in the braking torque M _{D is} negligible.

Used in the curves II, III and IV spring tongues are each provided with roof-shaped (triangular cross section) transverse ribs 21, wherein the roof angle of the braking transverse ribs in the trace II 30 ^o, IV was 60 at curve III 45 ^o and curve ^o. 7 to the right of the diagram of FIG. 7 there is a bar chart on which the abrasion depth T of the abrasion furrow 24 assigned to curves II, III and IV is given after complete unwinding of the tape supply and this shows that with an increasingly acute roof angle a significant increase in the Abrasion occurs. It also follows that, despite the different roof angles of the transverse ribs, the desired basic tendency of the braking torque curve over the unwinding speed in principle remains the same even at the different angles, and a suitable adjustment of the braking force to the respective requirements is possible via the choice of the angle, whereby how 7 reveals that with increasing flattening of the transverse ribs, higher braking torque values occur.

The course of the tape pull-off forces P shown in FIG. 8 of the entire hand-held device / exchangeable cassette unit indicates at curve V the forces which are required to drive the take-up spool 9 for the empty tape roll via the removal of the carrier tape 11 from the supply reel 8 a (inevitable) increase in the curve from its initial value to a (higher) final value can be seen, which results from the fact that the trigger lever arm on the supply reel 8 decreases steadily with increasing tape consumption and the trigger force P must therefore increase.

If the supply coil 8 is now braked via the build-up of a braking torque, the braking force is added to these basic force values according to curve V.

In Fig. 8, the curve I 'shows the course of the curve, which results for the pulling force under the measuring conditions of curve I from Fig. 7, so if the supply spool 8 is braked by pure friction by brake springs elastically pressed onto its end face (without wear effect). This shows that over the entire unwinding path, starting from a certain starting force required to start the cassette, an unacceptable increase in the practical use of the device P 'of the pulling force at the end of the unwinding path (namely after 130 revolutions of the Supply spool 8) occurs.

The curve II 'was measured for the same handheld device and the same exchangeable cassette, which corresponds to the curve profile II from FIG. 7. This results in a much smaller increase P˝ of the pulling force at the end of the tape supply on the take-up reel 8, although the curve starts from the same initial value as curve 1 '.

Instead of the arrangement of the spring tongues 20, transverse ribs 21 and locking knobs 22 shown in the previous figures, any other suitable arrangement for building up a braking torque with the desired course over the unwinding path could also be used, for example a flanged disc 23 with spur teeth, into which spring angled by 90 ^o engage tongues, which in turn are formed on the side wall 16.

Other suitable plastics for the formation of the wear members (transverse ribs 21) are, for. B. also plastics based on polyolefins in question.

Claims (10)

1. Interchangeable cassette for a hand-held device for transferring a film from a carrier tape to a substrate, in which a supply spool with a film coated with the carrier tape and a take-up spool are contained and the support tape from the supply spool via an application element protruding from the cassette back to the take-up spool guided and this is provided with a backstop, characterized in that the supply spool (8) is assigned a braking device (20, 21, 22) effective in its unwinding direction, the braking torque (M _D ) acting on the supply spool (8) at least after one initial number of revolutions of the supply reel (8) as the unwinding speed of the supply reel (8) increases until the unwinding of the tape supply (12) decreases therefrom. 2. Interchangeable cassette according to claim 1, characterized in that the braking device has a brake member (21) designed as a wearing part, which meshes with counter-elements (22) which are movable relative to it when the supply spool (8) rotates, the brake member (21) and counter-elements (22) transmissible force decreases with increasing wear of the brake member (21). 3. Interchangeable cassette according to claim 2, characterized in that the brake member designed as a wearing part consists of a roof-shaped transverse rib (21) attached to the free end of a resilient tongue (20) made of plastic, which with an annular closed row one Large number of locking knobs (22) combs. 4. interchangeable cassette according to claim 3, characterized in that the locking knobs are in the form of conical tips (22). 5. interchangeable cassette according to claim 3 or 4, characterized in that the spring tongue (20) on a cassette side wall (16) and the locking knobs (22) concentrically on an adjacent to this cassette side wall (16) attached flanged disc (23) of the supply spool (8) are formed. 6. interchangeable cassette according to one of claims 3 to 5, characterized in that the transverse rib (21) is integrally formed with the spring tongue (20) carrying it. 7. exchangeable cassette according to one of claims 3 to 6, characterized in that the cross section of each transverse rib (21) is substantially triangular. 8. interchangeable cassette according to claim 7, characterized in that the transverse rib (21) on its from the resilient tongue (20) projecting end edge (25) in cross section an opening angle (α) of at least 30 ^o and at most 60 ^o , preferably 45 ^o trains. 9. exchangeable cassette according to one of claims 3 to 8, characterized in that the locking knobs (22) are arranged centrally to the transverse rib (21). 10. interchangeable cassette according to one of claims 3 to 9, characterized in that two with respect to the annular closed row of locking knobs (22) by 180 ^o offset from each other resilient tongues (20) are provided, each with a transverse rib (21).

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