EP1132329B1 - Device for compensating a radial movement of the screw in a screw and nut drive - Google Patents

Abstract

The compensating device is used in a spindle drive (1) with at least three axially parallel rotatable threaded spindles (G1-G4) with bearings (L1-L4) having different or identical radial play (F1, F2). These include low-friction bearings (L2-L4) with play to compensate for the radial impact of the rotating spindles.

Description

The invention relates to a device for compensating a radial threaded spindle stroke of a spindle drive in order to avoid blocking the spindle drive when lifting a platform, in particular when lifting the platform with objects in a device.

There are spindle drives of the aforementioned type are known in which the platform mounted by means of several arranged on her bearing means on a plurality of axis-parallel spindles and axially along with the bearing means the spindles along, and in which one of the spindles is designed as a rotatably operable threaded spindle on a bearing means having a spindle nut bearing means is arranged, and one of the bearing means comprises a radial clearance to compensate for the radial threaded spindle stroke.

The DE-A-3514804 discloses a lifting device with a stored by spindle nut on lifting spindles platform which corresponds to the preamble of claim 1.

The DE-A-2417645 discloses a conveying device for lifting loads with a mounted on a threaded jack truck, between the truck and spindle nut relative shift is allowed.

EP-B1-0 024 944 discloses such apparatus for vertically raising and lowering a stack of flat articles (magnetic cards) in a card dispenser, wherein a platform supporting the stack is movable in the vertical stroke direction by means of a spindle drive having a threaded spindle and a cylindrical shank, and the platform during their stroke movement by means of the threaded spindle arranged parallel to the axis and spaced cylinder shaft out and secured against horizontal pivoting. The platform is hereby mounted by means of a spindle nut on the threaded spindle and by means of a bearing sleeve on the cylindrical shaft.

In order to avoid a jamming of the platform against the cylindrical shaft caused by the threaded spindle impact, or a blocking or sluggish movement of the platform, the spindle nut is in the form of a rectangular Klotzes (dome) in a pocket-shaped bearing cavity (in the region of a U-shaped recess) on one of the sides of the platform loosely, that is arranged to be freely movable radially in a horizontal plane around the threaded spindle. The horizontal or radial freedom of movement of the spindle nut to the platform here is slightly larger than the radial impact of the threaded spindle.

Disadvantage of this disclosed embodiment is that due to the use of a single threaded spindle for lifting the stack-bearing platform, with heavy stacks tilting and thus jamming or jamming of the platform on the cylindrical shaft or the threaded spindle can occur. In addition, due to the design of the bearing in heavy stacks high frictional forces by surface friction between the spindle nut (calotte) and the platform in the bearing cavity in the caused by the spindle stroke horizontal radial movement of the spindle nut against the platform, jamming the platform against the cylindrical shaft favor and cause high material abrasion at the bearing.

The invention is therefore an object of the invention to provide a device of the type mentioned, which does not have these disadvantages, but ensures a jam-free, accurate and efficient Hubbewegen a platform with heavy loads in an automatic device working, and also a simple low-wear Structure has.

The object is achieved with a device according to claim 1 according to the invention.

Advantageously, in a first bearing means of the platform arranged substantially radially backlash on a first spindle, a second bearing means on a radial bearing clearance on both sides of a second spindle, which is provided radially linearly extending to and away from the first spindle, and are third and further bearing means arranged around the associated third and further spindles with radial all around effective bearing clearance; or have in an alternative embodiment, all arranged on the threaded spindles bearing means of the platform on a radially all around effective bearing clearance.

The object is further achieved with a device according to claim 7 according to the invention in that the bearing means each have a concentric around the spindle arranged annular ball bearing, by means of which the radial bearing clearance between the platform and the spindles for balancing the threaded spindle stroke is generated friction.

Advantageously, the ball bearings each have a first planar, aligned for lifting perpendicular bearing shell and a second plane, plane-parallel to the first aligned bearing shell, between which, held by an annular cage, balls of the respective ball bearings are freely rotatably mounted, wherein the first bearing shell the ball bearing is rigidly connected to an associated spindle nut of the bearing means and the second bearing shell is rigidly connected to the platform; or in an alternative embodiment, the bearing means each have a concentric about a threaded spindle arranged around annular ball bearing, in which a first concave, ball-bearing shell of the ball bearing is rigidly connected to the spindle nut, and the second bearing shell in a plane-parallel to the first bearing shell position connected to the platform and has a plane bearing side for the balls.

Fig. 1

einen Spindeltrieb mit der erfindungsgemäßen Vorrichtung in einer räumlichen (schematischen) Darstellung durch einen Durchbruch eines Gehäuses gesehen,

Fig. 2

die erfindungsgemäße Vorrichtung nach Fig. 1 in einer Ansicht von oben und entlang einer Schnittlinie "A-A",

Fig. 3

die erfindungsgemäße Vorrichtung nach Fig. 2 in einer vergrößerten Teilansicht von oben und durch einen Durchbruch der Plattform hindurch,

Fig. 4a

die erfindungsgemäße Vorrichtung nach Fig. 2 & 3 in einer teilweise durchbrochenen Seitenansicht aus Richtung "C1",

Fig. 4b

die erfindungsgemäße Vorrichtung nach Fig. 2 & 3 in einer Seitenansicht aus Richtung "C2" entlang einer Schnittlinie "B-B",

Fig. 4c

die erfindungsgemäße Vorrichtung nach Fig. 4b mit einer alternativen Ausführungsform des Lagermittels mit konkaver, kugelführender Lagerschale am Kugellager,

Fig. 5

die erfindungsgemäße Vorrichtung nach Fig. 2 in einer alternativen Ausführungsform mit Begrenzungsmitteln zur Verhinderung einer horizontalen Bewegung der Plattform.

The other features and advantages are described in the description of the embodiments of the invention shown in the drawings and the other dependent claims. The drawing shows in the

Fig. 1

a spindle drive with the device according to the invention seen in a spatial (schematic) representation through a breakthrough of a housing,

Fig. 2

the device according to the invention Fig. 1 in a view from above and along a section line "AA",

Fig. 3

the device according to the invention Fig. 2 in an enlarged partial view from above and through a breakthrough of the platform,

Fig. 4a

the device according to the invention Fig. 2 & 3 in a partially open side view from the direction "C1",

Fig. 4b

the device according to the invention Fig. 2 & 3 in a side view from direction "C2" along a section line "BB",

Fig. 4c

the device according to the invention Fig. 4b with an alternative embodiment of the bearing means with a concave, ball-guiding bearing shell on the ball bearing,

Fig. 5

the device according to the invention Fig. 2 in an alternative embodiment with limiting means for preventing horizontal movement of the platform.

The following description Fig.1 to 5 refers to a preferred embodiment of the device according to the invention for compensating a threaded spindle stroke in order to avoid jamming of a spindle drive 1 having a plurality of spindles, which is used for lifting a sheet stack S supporting platform 2 of a sheet supply magazine in a conventional, not shown, sheet processing device such for example, a copier is provided. Of the sheet stack resting on the platform are in this case by means of a conventional, not shown sheet removal / transport unit the copier individual leaves automatically successively removed and fed to one or more sheet processing stations of the copier.

It will be understood by those skilled in the art that the inventive device may be used in other devices, such as card or other stackable article dispensers or input devices, as well as in printers, printers, or sheet sorters.

The in Fig.1 shown in a spatial, schematic representation through a breakthrough of a device housing 5, the inventive device having spindle drive 1, shows within the device housing 5, an upper 51 and a lower 52 substantially rectangular bearing plate 2 with four between them in axis-parallel, vertical orientation Z at four Spindles in the form of threaded spindles G1, G2, G3, G4. The upper bearing plate 51 has a recess for access to an upper side of the sheet stack S by hand and / or by means of the sheet removal / transport unit, so that only one edge region of the bearing plate remains in the form of a U.

The platform 2 is mounted by means of four bearing means L1, L2, L3, L4 arranged thereon on associated threaded spindles G1, G2, G3, G4, which are in accordance with FIG Fig. 2 different radial bearing clearance F1; F2 in the horizontal direction X; Y have.

For holding and guiding the sheet stack S, as in Fig. 2 and 5 shown on a platform 2 arranged on the base plate 20 a plurality of adjustable side stops 23 and rear stops 24 are mounted, which extend in the stroke direction and act laterally on the stack of sheets. In Fig. 1 these stops are omitted because of the clearer presentation of the invention.

The platform 2, together with the bearing means, can be moved axially along the spindles vertically in the direction Z, for which purpose all threaded spindles G1, G2, G3, G4 of the Spindle drive 1 synchronously by means of a single microprocessor-controlled drive unit 6 are rotatably driven in common. The drive unit 6 is controlled by a conventional, not shown control unit and sensor unit of the copying machine in its direction of rotation and rotation and has a drive motor 60 with drive pinion, as well as a driven via the drive pinion drive belt 61 in the form of a toothed belt. The toothed belt 61 is encircling all the belt wheels 62, which are arranged concentrically and rigidly connected to the threaded spindles G1, G2, G3, G4 in the region of the lower bearing plate 52.

In the preferred embodiment of the invention, according to Fig. 1 and 2 , A first bearing means L1 of the platform 2 is arranged substantially radially clearance on a first spindle G1, has a second bearing means L2, according to Fig. 1 to 4a , a radial bearing clearance F1 on both sides of a second spindle G2 in the direction Y, which is provided radially linearly extending to and away from the first spindle G1, and are, after Fig. 1 . 2 . 4b and 4c , the third and further bearing means L3, L4 with radial all-around bearing clearance F2 (in the direction X; Y) are arranged around the associated third and further spindles G3, G4. It follows during the lifting movement of the platform 2 in a spindle stroke of the threaded spindles G1-G4, a horizontal movement of the platform 2 in the X direction or transverse to the transport direction T of the leaves S (see Fig. 2 ), which is determined by the spindle stroke of the threaded spindles G1 and G2, and a horizontal movement in the direction Y or along the transport direction T, which is determined only by the spindle stroke of the threaded spindle G1.

The bearing means L1, L2, L3, L4 of the platform 2 are arranged in the embodiment according to the invention as low-friction bearing means with radial clearance F1, F2 for equalizing the radial stroke of the rotating threaded spindles G1, G2, G3, G4, such that a relative, radial Movement of the rotating spindles G1, G2, G3, G4 to the platform 2 with low frictional force or low effort is possible. As in Fig. 3 ; 4a-4c In this case, the bearing means L1, L2, L3, L4 each have an annular ball bearing 3 arranged concentrically around the spindles G1, G2, G3, G4, by means of which the radial bearing clearance F1 and F2 between the platform 2 and the spindles for balancing the lead screw stroke is generated friction.

The ball bearings 3 have, as in Fig. 3 . 4a-4b shown, in each case a first plane, for lifting movement aligned at right angles lower annular bearing shell 31 and a second plane, plane-parallel to the first aligned upper annular bearing shell 32, between which, held by an annular cage 33, 33.1, 33.2, balls 34 of the ball bearings freely rotatably mounted wherein the first bearing shell 31 of the ball bearings 3 is rigidly connected to the associated platform nut 2 with an associated spindle nut M1; M2; M3; M4 of the bearing means L1; L2; L3; L4 and the second bearing shell 32.

The bearing shells 31, 32 have, in the radial direction, a planar support width for the balls 34, which is greater than the maximum radial bearing clearance F1, F2 predetermined by the maximum spindle stroke, and the ball cage 33 has an outer 33.1 and a ball around the balls 34 an inner ring member in concentric arrangement about the spindles G1; G2; G3; G4 and about the spindle nuts M1; M2; M3; M4, the inner ring member 33.2 having an inner diameter corresponding to an outer diameter of the spindle nut M1; M2; M3; M4 substantially corresponds.

In an alternative embodiment according to Fig. 4c The bearing means L1, L2, L3, L4 each have an annular concentric ball bearing 4 arranged concentrically around a threaded spindle G1, G2, G3, G4 and having a first / lower concave, ball-guiding bearing shell 41 of the ball bearing 4, which is rigid with one M4; M4 of the bearing means L1; L2; L3; L4 is connected, and whose second / upper bearing shell 42 is rigidly connected to the platform 2 in a plane-parallel position relative to the first bearing shell 41 and has a planar support side for having freely rotating balls 44 of the ball bearing 4.

The spindle nuts M1, M2, M3, M4 arranged on the threaded spindles G1, G2, G3, G4 and movable by rotation of the spindles have, as in FIG Fig. 4a-4b shown, an axially to the axis of rotation of the spindles extending cylindrical shape or a cylindrical shank, wherein at the lower end of each spindle nut, a radially projecting cylindrical flange is mounted concentrically. On this flange of the spindle nut resting, centered by a smaller diameter exhibiting concentric ring member of the flange and rigidly connected to the flange (eg by press fit from the inner periphery of the bearing shell 31 on the outer circumference of the ring member), the lower / first annular bearing shell 31 is arranged.

Each upper / second annular bearing shell 32 of the ball bearings 33 is rigid at an underside of the platform 2, or their bearing points L1; L2; L3; L4, in the region of a passage opening for the associated spindle G1; G2; G3; G4 in an annular recess The upper bearing shell 32 of the ball bearing 3 and the spindle passage opening on the platform 2 in this case have an inner diameter of their passage openings whose radius by the amount of the required predetermined radial bearing clearance F1; F2 of the individual bearing points of the bearing means L1; L2; L3; L4 is greater than a radius of the outer diameter of the upper cylindrical shaft of the spindle nut M1; M2; M3; M4 projecting upwards through the passage openings. The outer diameter of the upper cylindrical shaft of the spindle nut also serves to center and guide the inner ring member 33.2 of the annular ball cage 33rd

A limitation of the radial bearing clearance F1, F2 between the bearing means 3, L2, L3, L4 of the bearing points or the platform 2 and the spindles G2, G3, G4 or the spindle nuts M1, M2, M3, M4 is by means of the platform 2 arranged and on the spindle nuts radially outwardly acting limiting means 21, 22 of the platform 2 effected, that is, the inner edge of the spindle passage openings at the bearing points L2, L3, L4 is formed as a limiting means 21, 22 for the radial bearing clearance F1, F2.

In order to ensure that the spindle nuts M1, M2, M3, M4 and thus the platform 2 are movable upwards and downwards in a lifting movement, ie that the spindle nuts do not rotate with the threaded spindles G1, G2, G3, G4, the spindle nuts are by means of holding means, for example in the form of retaining bolts 25 with the bearing points L1; L2; L3; L4 or loosely coupled to the platform 2 (see Fig. 3 ). For this purpose, the retaining bolt 25 is rigidly connected to the cylindrical shank of the spindle nut M2, M3, M4 and protrudes at its opposite end, freely movable in the axial direction (according to the bearing clearance F1) through a guide bore on a web 26 of the platform or inside Platform storage L2; L3; L4. The guide bore is chosen so large in its diameter that the radial bearing clearance F2 is ensured by the circular horizontal movement of the retaining bolt 25. An exception here is the bearing point L1 with spindle nut M1, since this spindle nut can be rigidly and directly connected to the platform 2 because of the predetermined play-free bearing L1 with its cylindrical shank.

In another, in Fig. 5 illustrated embodiment, all on the threaded spindles G1; G2; G3; G4 or spindle nuts M1; M2; M3; M4 arranged bearing means L1; L2; L3; L4 of the platform 2 an equal or unequal / different radially all around effective bearing clearance F2 on. For limiting the radial bearing clearance F2 between the bearing means 3; M1, M2, M3, M4 of the bearing points L1, L2, L3, L4 and the spindles G1, G2, G3, G4, and for preventing a horizontal radial movement of the platform 2 in the X, Y direction during its lifting movement, are stationary, device-side limiting means 50 which engage at right angles to the lifting movement on all four sides of the platform 2 or on the bottom plate 20 for the sheet stack stops 23, 24. The limiting means 50 are designed, for example, in the form of ribs or webs as part of the spindle drive housing 5 and extend along the lifting movement over the entire lifting height of the platform 2.

In a further, not shown, alternative embodiment of the invention, the spindles G1, G2, G3, G4 have a combination of threaded spindles and smooth cylinder shafts or cylinder columns, wherein the cylinder shafts serve to guide and as anti-twist and Verkippschutz for the platform 2. At the cylinder shafts while the spindle nuts are replaced by guide sleeves. In addition, only three rather than four spindles are provided in a polygon or triangle arrangement.

Parts list:

• F1 radial / two degrees of freedom bearing clearance on the second bearing means
• F2 radial / circumferential bearing clearance on the third and fourth bearing means
• G1 first threaded spindle of the spindle drive
• G2 second threaded spindle of the spindle drive
• G3 third threaded spindle of the spindle drive
• G4 fourth threaded spindle of the spindle drive
• L1 first storage means (storage location) of the platform
• L2 second storage means (storage location) of the platform
• L3 third storage means (storage location) of the platform
• L4 fourth storage means (storage location) of the platform
• M1 first spindle nut on first threaded spindle / first bearing means
• M2 second spindle nut on second threaded spindle / second bearing means
• M3 third spindle nut on third threaded spindle / on third bearing
• M4 fourth spindle nut on fourth threaded spindle / fourth bearing means
• Sheet-like, plate-shaped objects / objects (stack)
• T horizontal transport direction of the objects / sheets from the stack
• X first horizontal direction of movement of the platform
• Y second horizontal direction of movement of the platform
• Z vertical stroke direction of the platform / spindle drive
• 1st spindle drive with platform
• 2. Platform for picking up / dropping objects (sheet / plate pile)
• 3. annular ball bearing with ball cage u. Planer bearing shell (storage means)
• 4. alternative / annular ball bearing with concave / ball bearing bearing shell
• 5. Housing of the spindle drive
• 6. Drive unit for threaded spindles of the spindle drive
• 20. Base plate on platform for side / back stops (sheet / plate stack)
• 21. first limiting means for radial (s) bearing clearance F1 / platform movement (component of the platform)
• 22. second limiting means for radial (s) bearing clearance F2 / platform movement (part of the platform)
• 23. Side stop / strikes on floor plate for objects / sheets
• 24. Back stop / strikes on base plate for items / sheets
• 25. Retaining pin for spindle nut holder & guide on platform
• 26. Bar / rib on platform for retaining bolt guide
• 30th
• 31. first / lower planar bearing shell of the ball bearings
• 32. second / upper planar bearing shell of the ball bearings
• 33. annular cage for the balls
• 33.1. outer ring element of the cage
• 33.1. inner ring element of the cage
• 34. Balls of ball bearings
• 40th
• 41. first / lower concave, ball-bearing bearing shell (alternative ball bearing)
• 42. second / upper planar bearing shell of the alternative ball bearing
• 43rd
• 44. Balls of alternative ball bearings
• 50th alternative limiting means for platform (part of the spindle drive housing
• 51. Upper bearing plate for threaded spindles
• 52. Lower bearing plate for threaded spindles
• 60. Drive motor of the threaded spindle drive unit
• 61. Drive belt
• 62. Pulley to threaded spindle

Claims (11)

1. Lifting device comprising a platform, several axis-parallel spindles (G1. G2, G3, G4), several bearing means (L1, L2, L3, L4) in a polygonal arrangement of said platform, said bearing means being disposed to support the platform on the spindles, characterized by
   bearing means exhibiting radial bearing play (F1, F2) for the compensation of the radial runout of the rotating spindles,
   a first bearing means (L1) of the platform (2) being arranged on a first spindle (G1) without substantial radial play, a second bearing means (L2) displacing a radial bearing play (F1) on both sides of a second spindle (G2), said second bearing means being arranged so as to move in a radially linear direction toward the first spindle (G1) and away therefrom, and the third and additional bearing means (L3, L4) being arranged so as to display a bearing play (F2) effective in radial direction around the associated third and additional spindles (G3, G4).
2. Lifting device in accordance with Claim 1, characterized in that each of the bearing means (L1; L2; L3; L4) comprises a ring-shaped ball bearing (3) arranged concentrically around the spindles (G1; G2; G3; G4), said ball bearing being disposed to create a low-friction radial bearing play (F1; F2) between the platform (2) and the spindles in order to compensate for the runout of the threaded spindle.
3. Lifting device in accordance with Claim 1, characterized in that it is possible to limit the radial bearing play (F1; F2) between the bearing means (L2; L3; L4) and the spindles (G2; G3; G4) by means of limiting means (21; 22) that are arranged on the platform (2) and that act on the spindles in radial direction.
4. Lifting device in accordance with Claim 1, characterized in that stationary, apparatus-side limiting means (50) are arranged so as to limit the radical bearing play (F2) between the bearing means (L1; L2; L3; L4) and the spindles (G1; G2; G3: G4) and so as to avoid a radical movement of the platform (2), said limiting means acting at a right angle relative to the lifting movement on all four sides of the platform (2).
5. Lifting device in accordance with Claim 1, characterized in that each of the bearing means (L1; L2; L3; L4) comprises a ring-shaped ball bearing (3) concentrically arranged around the spindle (G1; G2; G3; G4), said ball bearing being disposed to create a low-friction radial bearing play (F1; F2) between the platform (2) and the spindles, in order to compensate for the runout of the threaded spindle.
6. Lifting device in accordance with Claim 5, characterized in that each of the ball bearings (3) comprises a first planar bearing shell (31) aligned at a right angle relative to the lifting movement and a second planar bearing shell (32) aligned plan-parallel to the first bearing shell, wherein between said bearing shells, held by a ring-shaped cage (33; 33,1; 33.2), balls (34) of the respective ball bearings are supported so as to be freely rotatable, said first bearing shell (31) of the ball bearings (3) being rigidly fastened to an associated spindle nut (M1; M2; 3; M4) of the bearing means (L1; L2; L3; L4) and said second bearing shell (32) being rigidly fastened to the platform (2).
7. Lifting device in accordance with Claim 6, characterized in that the bearing shells (31 ; 32) have a planar support surface for the balls (34), said surface extending in radial direction and being greater than the maximum radial bearing play (F1; F2) pre-specified by the maxi mum spindle runout, and that the bearing cage (33; 33.1; 33.2) around the bails (34) comprises an external (33.1) and an internal (33.2) ring element in a concentric arrangement around the spindles (G1; G2; G3: G4), the internal ring element (33,2) having an internal diameter that substantially correspond to an external diameter of the spindle nut (M1; M2; M3; M4).
8. Lifting device in accordance with Claim 5, characterized in that each of the bearing means (L1; L2; L3; L4) comprises a ring-shaped ball bearing (4) concentrically arranged around a threaded spindle (G1; G2; G3; G4), with a first concave, ball-carrying bearing shell (41) of the ball bearing being rigidly fastened to a spindle nut (M1; M2; M3; M4) of the bearing means (L1; L2; L3; L4), and said bearing's second bearing shell (42) being rigidly fastened, opposite the first bearing shell (41), in a position plan-parallel to the platform (2) and comprising a planar support side for balls (44) of the ball bearing (4).
9. Lifting device in accordance with Claims 1 through 7, characterized in that all the threaded spindles (G1; G2; G3; G4) of the spindle drive (1) can be driven together in a synchronous manner by means of a single microprocessor-controlled driving unit (6), and that the spindle drive (1) with its platform (2) performs a lifting movement in vertical direction.
10. Lifting device in accordance with Claims 1 through 9, characterized in that the lifting device is embodied as a sheet-processing apparatus, in particular as a copying apparatus.
11. Lifting device in accordance with Claims 1 through 9, characterized in that the spindles (G1; G2; G3; G4) comprise a combination of threaded spindles and cylindrical shafts, said cylindrical shafts being disposed to act as a guide and as an anti-torsion and anti-tilt protection for the platform (2).

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