NO892980L

NO892980L - SHEET CHANGER.

Info

Publication number: NO892980L
Application number: NO89892980A
Authority: NO
Inventors: Peter Ackeret
Original assignee: Licinvest Ag
Priority date: 1987-11-21
Filing date: 1989-07-20
Publication date: 1989-07-20
Also published as: NO892980D0; DK358689A; GB8916292D0; DK358689D0

Description

Foreliggende oppfinnelse angår en bladveksler for syklisk ombytting av de enkelte blad i en stabel slike, f.eks. fotografier, og bladveksleren er av den type som fremgår av den innledende del av det etterfølgende krav 1. En slik bladveksler er beskrevet med en rekke enkeltheter og vist med illustrasjoner i f.eks. de internasjonale patentskrifter WO 86/03018, WO 86/03019, WO 86/03021, WO 86/03022, WO 86/03026, WO 86/03028, WO 86/03029 og WO 86/03030, slik at den foreliggende beskrivelse a7"oppfinnelsens gjenstand begrenser seg til å angi de detaljer og funksjoner som er særlig kjennetegnende. , The present invention relates to a blade changer for cyclic replacement of the individual blades in a stack of such, e.g. photographs, and the blade changer is of the type that appears in the introductory part of the subsequent claim 1. Such a blade changer is described in a number of details and shown with illustrations in e.g. the international patents WO 86/03018, WO 86/03019, WO 86/03021, WO 86/03022, WO 86/03026, WO 86/03028, WO 86/03029 and WO 86/03030, so that the present description a7" the object of the invention is limited to indicating the details and functions which are particularly characteristic.

Generelt er slike bladvekslere bygget opp med to rammedeler, hvorav den ene danner et hus med et betraktningsvindu, mens den andre kan beveges frem og tilbake parallelt med betraktningsvinduets hovedplan i forhold til huset og mellom anslag, idet den andre del er utformet som en skyver. Av kostnadsmessige grunner blir rammedelene gjerne fremstilt av billigst mulig kunststoff eller plast, f.eks. polystyrol. In general, such blade exchangers are built up with two frame parts, one of which forms a housing with a viewing window, while the other can be moved back and forth parallel to the main plane of the viewing window in relation to the housing and between stops, the other part being designed as a pusher. For cost-related reasons, the frame parts are often made from the cheapest possible plastic or plastic, e.g. polystyrene.

Bladvekslerens fjæranordning omfatter gjerneThe blade changer's spring device often includes

fjærer som presser stabelen blad mot betraktningsvinduet, og videre kan det være anordnet trådfjærer i den indre rammede1, hvilke er plassert i en såkalt separatorbro som danner den indre tverrkant på den indre rammede1. Trådfjærene tjener til å fraskille et enkelt blad (eller bilde) fra stabelen over hele uttrekkingsområdet, ved press mot den ytre rammedel mot husets bunn på motsatt side av vinduet. Disse fjærer presser altså den indre rammedel permanent i retning mot betraktningsvinduet, og i tillegg virker, i det minste i bestemte uttrekks-posisjoner for den bevegelige rammedel, fjærkreftene fra denne stabelmottrykksanordning slik at den indre rammedel kommer til å ligge an med et temmelig stort trykk mot den ytre rammedel, sideveis på høyde med vinduet. Resultatet er at vekslings-eller omstablingsbevegelsen kommer til å gå ganske tregt, i det minste over deler av uttrekksområdet, slik at det kan for-årsakes rivetendenser som snart kan gjøre veksleren ubrukbar, særlig når rammedelene er fremstilt av billig kunststoff - såsom polystyrol. springs that press the stack of blades against the viewing window, and further there may be arranged wire springs in the inner frame1, which are placed in a so-called separator bridge that forms the inner transverse edge of the inner frame1. The wire springs serve to separate a single leaf (or picture) from the stack over the entire extraction area, by pressing against the outer frame part against the bottom of the housing on the opposite side of the window. These springs thus permanently press the inner frame part in the direction of the viewing window, and in addition, at least in certain extraction positions for the movable frame part, the spring forces from this stack counter-pressure device work so that the inner frame part comes to rest with a rather large pressure towards the outer frame part, laterally at the height of the window. The result is that the changing or re-stacking movement will be quite slow, at least over parts of the extraction area, so that tearing tendencies can be caused which can soon render the changer unusable, especially when the frame parts are made of cheap plastic - such as polystyrene.

Det ligger således fore en oppgave for den foreliggende oppfinnelse å utforme en bladveksler av den allerede kjente type og som er forbedret ved at den kan beveges lett og med minimal slitasje, uten å dermed være ugunstig i fremstil-ling av prismessige årsaker. It is thus a task for the present invention to design a blade changer of the already known type and which is improved in that it can be moved easily and with minimal wear, without thus being disadvantageous in production for price reasons.

Ifølge oppfinnelsen angis løsningen av denne oppgave slik som angitt i karakteristikken i det etterfølgende krav 1, og underkravene til dette hovedkrav angir videre foretrukne utforminger av oppfinnelsens konsept. According to the invention, the solution to this problem is stated as stated in the characteristic in the subsequent claim 1, and the sub-claims of this main claim further state preferred designs of the invention's concept.

I denne henseende foretrekkes at den første rammedel er utformet som et hus som omslutter den andre rammedel i form av en skyver. Skyveren fører, når den trekkes ut, den resterende del av stabelen, heretter kalt reststabelen, ut etter at ett blad, enkelbladet, er skilt fra stabelen på den side av denne som i huset vender fra dettes betraktningsvindu, og når skyveren på ny skyves inn i huset blir dette enkeltblad så ført inn i stabelen igjen, men nå på dennes motsatte side, dvs. den side som vender mot vinduet. For å kunne utføre en slik bladveksling har skyveren en indre såkalt separatorbro i form av en indre tverrvegg, og denne bro glir over enkeltbladet som presses mot betraktningsvinduet og følgelig også mot separatorbroen av et mottrykkssystem i huset. I en slik utførelse foretrekkes at separatorbroen støttes rullende mot enkelbladet ved hjelp av ruller, og at også skyveren støttes mot huset med ruller på den side som vender fra betraktningsvinduet, slik at skyveren får en tosidig rulleopplagring, i alle fall over arbeidsområdet for fjærkreftene. In this respect, it is preferred that the first frame part is designed as a housing which encloses the second frame part in the form of a pusher. The pusher, when it is pulled out, leads the remaining part of the stack, hereafter called the remaining stack, out after one leaf, the single leaf, has been separated from the stack on the side of it facing the viewing window in the house, and when the pusher is pushed in again in the house, this single sheet is then fed back into the stack, but now on its opposite side, i.e. the side facing the window. In order to be able to perform such a blade change, the pusher has an internal so-called separator bridge in the form of an internal cross wall, and this bridge slides over the single blade which is pressed against the viewing window and consequently also against the separator bridge by a counter pressure system in the housing. In such an embodiment, it is preferred that the separator bridge is supported rolling against the single leaf by means of rollers, and that the pusher is also supported against the housing with rollers on the side facing the viewing window, so that the pusher gets a two-sided rolling support, in any case above the working area of the spring forces.

En foretrukket utførelsesform av oppfinnelses-gjenstanden er fremstilt på de tilhørende tegninger og skal gjennomgås i det følgende med støtte i disse, idet fig. 1 viser et delutsnitt parallelt med betraktningsvinduet og ved delvis uttrukket skyver, fig. 2 viser et tverrsnitt normalt på betraktningsvinduets hovedplan, fig. 3 viser skyveren fra siden, fig. 4 viser et forstørret utsnitt fra fig. 3, fig. 5 viser et forstørret utsnitt fra fig. 2, hvor flere detaljer er tatt med, fig. 6 viser skjematisk og i delvis utsnitt normalt på betraktningsvinduets hovedplan og parallelt med skyverens bevegelsesretning hvordan denne støttes inne i huset, fig. 7 viser den komplette skyver i perspektiv, fig. 8 viser et for-størret detaljutsnitt fra fig. 7, og fig. 9 viser en alterna-tiv glidelageranordning. A preferred embodiment of the object of the invention is shown in the associated drawings and will be reviewed in the following with support in these, as fig. 1 shows a partial section parallel to the viewing window and with partially extended sliders, fig. 2 shows a cross-section normal to the viewing window's main plane, fig. 3 shows the pusher from the side, fig. 4 shows an enlarged section from fig. 3, fig. 5 shows an enlarged section from fig. 2, where more details are included, fig. 6 shows schematically and in partial section normally on the viewing window's main plane and parallel to the direction of movement of the pusher how it is supported inside the housing, fig. 7 shows the complete pusher in perspective, fig. 8 shows an enlarged detail section from fig. 7, and fig. 9 shows an alternative sliding bearing device.

Blad- eller bildeveksleren ifølge det foretrukne utførelseseksempel omfatter et hus 20 og en skyver 22 som kan trekkes ut og skyves inn i forhold til dette. I en full frem-og tilbakegående bevegelsessyklus trekkes det nederste blad i en bladstabel som ligger i bladveksleren ut fra stabelen og føres deretter tilbake på motsatt side av denne, nemlig til den stabelende som vender mot betraktningsvinduet, slik at stabelen etterhvert syklisk stables om. Bladene kan f.eks. være fotografier. Når skyveren er skjøvet inn i huset presses stabelen mot husets 20 betraktningsvindu 24 av gjennomsik-tig kunststoff, og da av to parallelle skinner 26 med motan-legg i husets bunn 30 via en fjæranordning som består av en bladfjær 28 på hver side. The sheet or image changer according to the preferred embodiment comprises a housing 20 and a pusher 22 which can be pulled out and pushed in relative to this. In a full reciprocating motion cycle, the lowest blade in a blade stack located in the blade changer is pulled out of the stack and then brought back to the opposite side of it, namely to the end of the stack facing the viewing window, so that the stack is eventually cyclically restacked. The leaves can e.g. be photographs. When the pusher has been pushed into the housing, the stack is pressed against the viewing window 24 of the housing 20 made of transparent plastic, and then by two parallel rails 26 with abutments in the bottom of the housing 30 via a spring device consisting of a leaf spring 28 on each side.

Skyveren 22 omfatter et gripestykke 32 som er forbundet med den såkalte separator 36 som dannes av en indre tverrvegg, via to langsgående skyverskinner 34 med L-tverrsnitt. På den side av separatoren 36 som vender mot husets bunn 30 er det innlagt to ruller 40 som kan rulle mot skinnene 26. På skinnene finnes et friksjonsbelegg 42 som tjener som underlag for rullene. Når skyveren trekkes ut av huset presses det nederste enkeltblad i stabelen, dvs. det blad som ligger på motsatt side av betraktningsvinduet, mellom rullene og friksjonsbelegget 42 som følge av kraften fra bladfjærene 28 og slik at enkeltbladet holdes fast, mens reststabelen trekkes ut av skyveren. Når skyveren på ny skyves inn i huset løftes det fraskilte enkeltblad over separatoren 36 og føres på ny inn i stabelen, på dennes motsatte side. The pusher 22 comprises a gripping piece 32 which is connected to the so-called separator 36 which is formed by an inner cross wall, via two longitudinal pusher rails 34 with an L-section. On the side of the separator 36 which faces the bottom of the housing 30, two rollers 40 are inserted which can roll against the rails 26. On the rails there is a friction coating 42 which serves as a base for the rollers. When the pusher is pulled out of the housing, the lowest single leaf in the stack, i.e. the leaf that is on the opposite side of the viewing window, is pressed between the rollers and the friction coating 42 as a result of the force from the leaf springs 28 and so that the single leaf is held firmly, while the remaining stack is pulled out by the pusher . When the pusher is again pushed into the housing, the separated single leaf is lifted over the separator 36 and fed back into the stack, on its opposite side.

Den kraft som bladfjærene virker med er ganske betydelig. Kraften virker via skinnene 26, rullene 40 og separatoren 36 slik at skyveren presses mot oversiden av huset 20, i hvilket skyveren føres. Da den friksjonskraft som mot-setter seg skyverbevegelsen vil være avhengig av presskraften og friksjonskoeffisienten, idet den første imidlertid ikke kan bringes under en viss funksjonsbetinget minstegrense, er det ifølge oppfinnelsen sørget for at friksjonskraften ved anvendelse av materialpar med liten friksjonskoeffisient holdes nede. The force with which the leaf springs act is quite significant. The force acts via the rails 26, the rollers 40 and the separator 36 so that the pusher is pressed against the upper side of the housing 20, in which the pusher is guided. Since the frictional force that opposes the pusher movement will depend on the pressing force and the coefficient of friction, the first of which, however, cannot be brought below a certain function-related minimum limit, according to the invention it is ensured that the frictional force when using material pairs with a small coefficient of friction is kept down.

Av denne grunn er det i området ved separatoren 36 (se fig. 6) anordnet lagerbukker 44 på siden og i de langsgående L-skinner 34, og i disse lagerbukker opptas et friksjonsreduserende element i form av et kontaktstykke, utformet som en støtterulle 45. For at fremstillingen av skyveren ikke skal kreve for komplisert sprøytestøpeverktøy er det anordnet en sliss 46 i ytterveggen 48 på de klossformede lagerbukker 44 på den side av disse som vender mot betraktningsvinduet, og slissene 46 går parallelt med hverandre. På innersiden av lagerbukkene er anordnet en not 50. I slissen 46 hhv. noten 50 ligger rullens 45 lagertapper 52 hhv. 54 glidbart lagret, og rullen 45 er laget i ett stykke av kunststoff. Ut fra de smale tverrvegger 56 rager på oversiden av den lagerbukk 44 som er åpen på undersiden fremspring 58 innover, og disse spriker elastisk fra hverandre når rullen 45 føres inn og beveger seg på ny elastisk mot hverandre slik at de hindrer at rullen faller ut under montasjen. Dette fremgår best fra fig. 4, mens man på fig. 3 også kan se en styreklaff 60 som forøvrig ikke egentlig vedrører den foreliggende oppfinnelse. For this reason, in the area of the separator 36 (see Fig. 6), bearing brackets 44 are arranged on the side and in the longitudinal L-rails 34, and in these bearing brackets a friction-reducing element in the form of a contact piece, designed as a support roller 45, is accommodated. So that the manufacture of the pusher does not require overly complicated injection molding tools, a slot 46 is arranged in the outer wall 48 of the brick-shaped bearing blocks 44 on the side of these that faces the viewing window, and the slots 46 run parallel to each other. A groove 50 is arranged on the inside of the bearing trays. In the slot 46 or the groove 50 lies on the roller's 45 bearing pins 52 respectively. 54 slidingly stored, and the roller 45 is made in one piece of plastic. Projections 58 protrude inwards from the narrow cross walls 56 on the upper side of the bearing frame 44, which is open on the underside, and these spring apart elastically when the roll 45 is brought in and move again elastically towards each other so that they prevent the roll from falling out under the assembly. This is best seen from fig. 4, while on fig. 3 can also see a control flap 60 which, by the way, does not really relate to the present invention.

Når huset og skyveren sprøytestøpes av f.eks. polystyrol benyttes for rullen 45 fortrinnsvis polyamid, og ved en kombinasjon av disse to materialer oppnås meget lave frik-sjonskoeffisienter, særlig er dette viktig der hvor tappene 52 og 54 glir i slissen 46 hhv. noten 50, og det er dessuten viktig i området hvor rullefriksjonen mellom rullens 45 om-krets og en kontaktbane i form av en skinne 62 i huset 20, parallelt med skyverens uttrekksretning, gjør sin virkning. When the housing and pusher are injection molded by e.g. polystyrene is used for the roll 45, preferably polyamide, and a combination of these two materials achieves very low coefficients of friction, this is particularly important where the pins 52 and 54 slide in the slot 46 respectively. the groove 50, and it is also important in the area where the rolling friction between the circumference of the roller 45 and a contact path in the form of a rail 62 in the housing 20, parallel to the pusher's withdrawal direction, has its effect.

Det er innlysende at denne skinne 62 kan utføresIt is obvious that this rail 62 can be made

i ett med huset under dettes sprøytestøping, eller skinnen kan være innføyd inn i den øverste del, overskallet, av huset. Alternativt kan man såsom vist på fig. 9 anordne et ikke om-løpende glidestykke 45a på skyveren, av f.eks. polyamid, eller skyveren kan være fremstilt av polystyrol og ha en skinne av polyamid. in one with the housing during its injection molding, or the rail can be inserted into the upper part, the shell, of the housing. Alternatively, as shown in fig. 9 arrange a non-rotating sliding piece 45a on the pusher, of e.g. polyamide, or the pusher can be made of polystyrene and have a rail of polyamide.

Fra den foregående utredning fremgår at skyveren støttes friksjonsfattig i "den bakre" eller "indre" del av From the previous report it appears that the pusher is supported with low friction in the "rear" or "inner" part of

huset, på den ene side ved hjelp av rullene 40 som vender ned-over, og på den annen side ved hjelp av rullene 45 som vender oppover. Man Kunne også ha anordnet en friksjonsfattig støtte i the housing, on the one hand using the downward-facing rollers 40, and on the other hand using the upward-facing rollers 45. One could also have arranged a low-friction support in

det fremre skyveområde for skyveren, men i dette område er ikke skyveren så sterkt fjærspent, slik at nødvendigheten av friksjonsreduserende midler ikke er så stor .. the forward thrust area of the pusher, but in this area the pusher is not so strongly spring-loaded, so that the need for friction-reducing agents is not so great ..

Imidlertid er det en fare for at skyveren, helt frem til dennes ytterste endeanslag, kommer til å kante i et plan som ligger parallelt med betraktningsvinduets hovedplan og faktisk kunne klemmes fast. Av denne grunn er det ønskelig at de flater som klemmer mot hverandre i dette skyverområde har liten friksjonskoeffisient mot hverandre. Oppfinnelsen forutser derfor at det er de frie ytre ender av tappene 52 som ligger an mot listformede føringer i form av tverrvegger 64 i huset, mens de indre tapper 54 på rullene 4.4, 45 på grunn av noten 50 støttes i motlagere (fig. 5). I den utførelse som er vist på fig. 9 oppheves denne klemvirkning med sidefremspring 66 på glidestykket 45a, og hvis skinnen da var utført av polyamid, mens glidestykket av polystyrol, måtte også tverrveggen 64 være utført av polyamid. Det skal imidlertid presiseres at de angitte materialkombinasjoner bare er eksempler, og man kan f.eks. la rullene 45 være av metall, og det kan også være materialet for rullene 40. However, there is a danger that the pusher, right up to its outermost end stop, will edge in a plane that is parallel to the viewing window's main plane and could actually be clamped. For this reason, it is desirable that the surfaces that clamp against each other in this sliding area have a small coefficient of friction against each other. The invention therefore foresees that it is the free outer ends of the pins 52 that rest against strip-shaped guides in the form of cross walls 64 in the housing, while the inner pins 54 on the rollers 4.4, 45 are supported in counter bearings due to the groove 50 (fig. 5) . In the embodiment shown in fig. 9, this clamping effect is canceled out by lateral protrusions 66 on the sliding piece 45a, and if the rail was then made of polyamide, while the sliding piece was made of polystyrene, the transverse wall 64 would also have to be made of polyamide. However, it must be specified that the specified material combinations are only examples, and one can e.g. let the rollers 45 be of metal, and that may also be the material for the rollers 40.

Ved helt innskjøvet skyver 22 ligger ikke rullene 40 an mot skinnene 26, men fjærene presser da hele stabelen uavhengig av dennes tykkelse mot betraktningsvinduet. When pusher 22 is fully pushed in, the rollers 40 do not rest against the rails 26, but the springs then press the entire stack, regardless of its thickness, against the viewing window.

Det er innlysende at føringen av skyveren i huset ikke må påvirke vekslingsfunksjonen, dvs. at rullene 45 må være anordnet på siden av den bane som det enkeltbilde som skal omplasseres i stabelen beveger seg langs, under skyverens frem- og tilbakegående bevegelse i huset. It is obvious that the guiding of the pusher in the housing must not affect the switching function, i.e. that the rollers 45 must be arranged on the side of the path along which the single image to be relocated in the stack moves, during the pusher's reciprocating movement in the housing.

Videre må tappene 52 rage så langt ut i forhold til lagerbukkenes 44 yttervegg at bukkene ikke kommer til å berøre tverrveggene 64 på siden og forårsake fastklemming, heller ikke ved kanting av skyveren i sin helt uttrukne stilling. Av denne grunn er lagerbukkene 44 avskrådd på kanten 70 (den kritiske ende). Furthermore, the pins 52 must protrude so far in relation to the outer wall of the bearing brackets 44 that the brackets will not touch the cross walls 64 on the side and cause jamming, not even when edging the pusher in its fully extended position. For this reason, the bearing brackets 44 are chamfered on the edge 70 (the critical end).

I utførelseseksemplet er de friksjonsreduserende elementer anordnet på skyveren, men det er også mulig å anordne disse i huset, særlig når det er ønskelig med en frik-sjonsreduksjon også i nærheten av husets åpning, den åpning In the design example, the friction-reducing elements are arranged on the pusher, but it is also possible to arrange these in the housing, especially when it is desirable to have a friction reduction also near the opening of the housing, that opening

som skyveren beveges gjennom.through which the pusher is moved.

I det minste én av lagerbukkene 44 har en dertil anordnet holder 72 for en anslagsdemper 74 av filt e.l. materiale og som ved uttrekkingen av skyveren kommer til å gli mot den indre endekant av huset (se også fig. 1). Fra husets bunn 30 rager knaster 76 opp mellom skyverskinnenes bakoverskrådde ribber 78, og hver av de to knaster 76 har likeledes en anslagsdemper 80 for anslag mot en tverrbro 82 på den respektive skyverskinne 34 ved helt innskjøvet skyver. At least one of the bearing trays 44 has a holder 72 for a shock absorber 74 made of felt or similar. material and which, when the pusher is pulled out, will slide towards the inner end edge of the housing (see also fig. 1). From the bottom of the housing 30, lugs 76 project up between the pusher rails' backwards beveled ribs 78, and each of the two lugs 76 likewise has an impact damper 80 for impact against a cross bridge 82 on the respective pusher rail 34 when the pusher is fully inserted.

Claims

1. Blade changer with a first frame part (20) and a second frame part (22) which can be pulled out and pushed in relative to the first in a direction parallel to the main plane for a viewing window (24) arranged in one of the frame parts, for cyclic restacking of each leaf in a stack of such, and a spring device (28) which, at least in one relative position between the frame parts (20, 22), braces them against each other in a direction normal to the main plane of the viewing window (24), CHARACTERIZED IN that the areas of the frame parts (20, 22) against which the spring forces from the spring device (28) act have at least one friction-reducing element (45, 45a).

2. Blade changer according to claim 1, CHARACTERIZED IN THAT each friction-reducing element consists of a material which provides a low coefficient of friction compared to the material of which the frame parts are made.

3. Blade changer according to claim 1 or 2, CHARACTERIZED BY the fact that one of the frame parts has a contact track (62) whose material, together with the material in a corresponding contact piece (45, 45a) arranged on the other frame part, forms a friction-reducing material pair.

4. Blade changer according to claim 3, CHARACTERIZED IN THAT the contact path (62) consists of a material which provides a low coefficient of friction together with the material of the contact piece.

5. Blade changer according to claim 3, CHARACTERIZED IN THAT the contact piece is arranged rollable on the contact path.

6. Blade changer according to claim 5, CHARACTERIZED IN THAT the contact piece consists of dense material which provides a low coefficient of friction together with the material in the contact path.

7. Blade changer according to claim 5 or 6, CHARACTERIZED BY the fact that the contact piece consists of a material that provides a low coefficient of friction together with the material in the frame part in which the contact piece is rotatably stored.

8. Blade changer according to one of claims 3-7, CHARACTERIZED IN THAT the frame parts are injection-molded from the material polystyrene and that the contact piece consists of polyamide.

9. Blade changer according to one of claims 3-8, CHARACTERIZED IN THAT the one frame part (22) has an internal transverse wall (36) against which the spring forces from the spring device (28) act, and that this frame part (22), at least in the area on both sides of the transverse wall (36), is supported by a respective contact piece (45, 45a) on the second frame part (20).

10. Blade changer according to claim 9, CHARACTERIZED IN THAT this frame part (22) has side walls (34) which carry the counter-stroke pieces (45, 45a) and are connected to the transverse wall (36).

11. Blade changer according to claim 10, CHARACTERIZED IN THAT the side walls have bearing trays (44) in which a respective roller (45) is rotatably engaged.

12. Blade changer with a first frame part (20) and a second frame part (22) which can be pulled out and pushed in relative to the first in a direction parallel to the main plane for a viewing window (24) arranged in one of the frame parts, for cyclic restacking of one and one blade in a stack of such, preferably according to claim 1, CHARACTERIZED IN THAT the contact between the second frame part (22) and a guide (64) which is arranged on the first frame part (20) and supports the second frame part (22) from the side, friction-reducing is carried out for a position of the second frame part where this is pulled out in relation to the first, right up to an end stop.

13. Blade changer according to claim 12, CHARACTERIZED IN THAT at least one of the frame parts has a contact piece (52, 66) in its guide area, and that this contact piece exhibits a low coefficient of friction together with the material in the other frame part.

14. Blade changer according to claims 1 and 13, CHARACTERIZED BY the fact that the friction-reducing element and the contact piece are designed as a continuous building element.

15. Blade changer according to claims 5 and 14, CHARACTERIZED BY the fact that the common building element is designed as a roller (45) with a protruding pin (52) which protrudes on the side over the side wall of the frame part.

16. Blade changer according to claim 1 or 12, CHARACTERIZED IN THAT the first frame part is a housing (20) in which the second frame part in the form of a pusher (22) can be moved, and that the pusher is provided with a friction-reducing contact piece (45, 45a, 52, 66) near its inner end.

17. Blade changer according to claim 16, CHARACTERIZED IN THAT the contact piece supports itself in two directions which are normal to each other and in relation to the direction of movement of the pusher, against contact tracks (62, 64) in the housing.

18. Blade changer according to claim 17, CHARACTERIZED IN THAT at least one roller (45) is stored at the inner end of the pusher in relation to the housing and in the form of a contact piece, and that this or each roller is supported by means of an outwardly directed free end of a tap - pen (52) for storage.

19. Blade changer according to claim 18, CHARACTERIZED IN THAT the bearing pin (52) projects so far outside a bearing part (44) for the roller (45) that a jamming of the pusher (22) in the housing (20) is excluded, even if the pusher were to edge.

20. Blade changer according to one of the preceding claims, CHARACTERIZED IN THAT the first frame part is designed as a housing (20) and has means for holding the blade in the stack that is farthest from the viewing window, when the second frame part, designed as a pusher (22), is pulled out from the housing and takes the rest of the stack with it, and that when the pusher is pushed in, it moves over the fixed leaf to the end of the stack that faces the viewing window.

21. Blade changer according to claim 20, CHARACTERIZED IN THAT the pusher has an internal transverse wall (36) which serves as a residual stack carrier which slides over the spring device (26-28) when the pusher is withdrawn from the housing.

22. Blade changer according to claim 21, CHARACTERIZED IN THAT the spring device comprises at least one rail-shaped element (26) extending in the same direction as the movement direction of the pusher.

23. Blade changer according to claim 21, CHARACTERIZED BY two parallel rail-shaped elements (26) which are each supported by a leaf spring (28).

24. Blade changer according to claims 20 - 23, CHARACTERIZED IN THAT the transverse wall (26) of the pusher (22) has rollers (40) on the side facing the viewing window and which, when the pusher is pulled out, clamp against the separated blade, while when the pusher is pushed in, they roll against the elements (269.

25. Blade changer according to claim 24, CHARACTERIZED IN THAT the rollers (40) consist of a material that provides a low coefficient of friction together with the building elements that come into sliding or rolling contact with the material in the rollers.

26. Blade changer according to claim 23, 24 or 26, CHARACTERIZED BY the fact that both rail-shaped elements (26) are arranged symmetrically in relation to a central plane which extends along the movement direction of the pusher.

27. Blade changer according to claims 23 and 24, CHARACTERIZED IN THAT the pusher (22) has two longitudinal pusher rails (34) extending in the same direction as the direction of movement of the pusher and which are connected to each other via the transverse wall (369.

28. Blade changer with a housing provided with a viewing window, a pusher that can be pulled out and pushed in relative to the housing in a direction parallel to the main plane of the viewing window, and a spring back pressure device arranged in the housing on the opposite side of the viewing window, CHARACTERIZED IN THAT the pusher supports itself with first roller bodies (40) against the spring counter-pressure device (26, 28) and with second roller bodies (45) supports itself against the housing (20) on the opposite side of the spring counter-pressure device.

29. Blade changer according to claim 1 or 12, CHARACTERIZED BY the fact that at least one of the frame parts has two sliding pieces which touch the other frame part in two allocated and narrowly limited places.

30. Blade changer according to claim 29, CHARACTERIZED BY the fact that both frame parts have respective two sliding pieces.

31. Blade changer according to claim 29, CHARACTERIZED IN THAT the sliding pieces have two contact surfaces that run perpendicular to the contact surfaces that absorb the spring tension from the spring device.

32. Blade changer according to claim 29, CHARACTERIZED IN THAT, in addition to the sliding pieces with contact surfaces for absorbing the spring tension from the spring device, further sliding pieces with contact surfaces are arranged which stand normally on the first ones.

33. Blade changer according to claim 31 or 32, CHARACTERIZED IN THAT the further contact surfaces abut against the second frame part, also when the frame parts have edges in relation to each other.

34. Blade changer according to claim 29, CHARACTERIZED IN THAT the sliding pieces are fitted into one frame part and rest with sliding friction against the other.

35. Blade changer according to claim 11, CHARACTERIZED IN THAT each bearing bracket has a one-sided open bearing for storing the rolls, and that this bearing opens out in a direction that coincides with the acting spring forces.

36. Blade changer according to claim 35, CHARACTERIZED IN THAT each bearing bracket has a locking element which springs out when the rollers are inserted to prevent them from falling out.

37. Blade changer according to one of the preceding claims, CHARACTERIZED BY at least one impact damper (74, 80) on at least one of the frame parts, and that this dampens in an assigned end position the relative frame part movement slides on a cross bridge (82) on the respective second frame part.