Spindle drive

Abstract

A spindle drive comprising a threaded spindle with an external thread, a spindle nut with an internal thread that is in engagement with the external thread of the threaded spindle, characterized in that the external thread of the threaded spindle has multiple threaded areas that are separated from each other by first flattenings on their circumference extending in the longitudinal direction, and the first flattenings have guide areas that abut the core diameter of the internal thread of the spindle nut.

Claims

1. A spindle drive comprising: a threaded spindle with an external thread, a spindle nut with an internal thread that is in engagement with the external thread of the threaded spindle, characterized in that the external thread of the threaded spindle has multiple threaded areas that are separated from each other by first flattenings on the circumference of the threaded spindle and extending in the longitudinal direction, and the first flattenings have guide areas that abut the core diameter of the internal thread of the spindle nut.

2. The spindle drive according to claim 1, in which the threaded spindle is an injection molded part.

3. The spindle drive according to claim 1, in which the threaded spindle is made of a first plastic, wherein the threaded spindle is injection molded from the first plastic, or in which the threaded spindle is made of a metal, wherein the threaded spindle is produced by means of metal injected molding (MIM).

4. The spindle drive according to claim 1, in which the first flattenings support guide ribs that have the guide areas on outer ends.

5. The spindle drive according to claim 1, in which the threaded spindle has only two first flattenings that are diametrically opposite each other, wherein the threaded spindle preferably has only two guide ribs that are diametrically opposite each other.

6. The spindle drive according to claim 4, in which the guide ribs have a second flattening on each end and, bordering two side edges of the second flattening, guide areas at a distance from a central axis of the threaded spindle corresponding to half of the core diameter of the spindle nut.

7. The spindle drive according to claim 6, in which the first flattenings are planar surfaces and/or in which the second flattenings are planar surfaces.

8. The spindle drive according to claim 1, in which the threaded areas of the external thread taper between the first flattenings in a radial direction to the outside.

9. The spindle drive according to claim 1, in which outer edges of guide ribs and/or transitions from the guide ribs to the first flattenings are rounded.

10. The spindle drive according to claim 1, in which side edges of thread profiles delimited by the first flattenings are rounded.

11. The spindle drive according to claim 1, in which transitions of flanks of thread profiles to the core diameter of the threaded spindle and/or edges of the thread profiles in a radial direction are rounded.

12. The spindle drive according to claim 1, in which the spindle nut is produced from a second plastic and/or from a metal.

13. The spindle drive according to claim 12, in which the first plastic is a high-performance plastic or an engineering plastic and/or in which the second plastic is a high-performance plastic or an engineering plastic.

14. The spindle drive according to claim 1 comprising an electric drive motor that is coupled to the threaded spindle or the spindle nut.

15. The spindle drive according to claim 1, having a metering device.

16. The spindle drive according to claim 1, having a measuring device, in particular a micrometer gauge.

17. The spindle drive according to claim 1, having a dosing device.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the drawings:

(2) FIG. 1 shows an electronic manual dosing device in a perspective view from the side;

(3) FIG. 2 shows the lower part of the same dosing device without the front half of the housing in the same perspective view;

(4) FIG. 3 shows the spindle drive and electric drive motor of the same dosing device in a perspective view from the side;

(5) FIG. 4 shows the spindle drive of the same dosing device in an enlarged, partially exploded perspective view from the side;

(6) FIG. 5 shows the threaded spindle of the same dosing device in an enlarged, perspective partial view;

(7) FIG. 6 shows the spindle drive in a cross-section through the spindle nut;

(8) FIG. 7 shows enlarged detail VII from FIG. 6;

(9) FIG. 8 shows another electronic manual dosing device in a perspective view from the side;

(10) FIG. 9 shows a vertical section of the same manual dosing device;

(11) FIG. 10 shows the lower part of the same manual dosing device with dosing drive in a perspective view transversely from the side;

(12) FIG. 11 shows a vertical section of the lower part of the same manual dosing device with dosing drive;

(13) FIG. 12 shows the same dosing drive in a perspective view from the side;

(14) FIG. 13 shows the same dosing drive in a rear view;

(15) FIG. 14 shows a micrometer gauge according to the invention in a perspective view from the side.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(16) In the present application, “up” and “down” as well as indicators derived therefrom refer to a vertical orientation of the threaded spindle and arrangement of the drive motor above the threaded spindle.

(17) Features of various exemplary embodiments that are addressed with the same terms are provided with the same reference signs in the following.

(18) The electronic manual dosing device 1 according to FIGS. 1 and 2 is an electronic manual dispenser. It has a rod-shaped housing 2 that is divided in the longitudinal direction into a front housing hull 3 and a rear housing hull 4.

(19) On the front side of the housing 2, a selection wheel 5 for selecting the respective operating mode is located on the upper end. By means of the selection wheel 5, the dosing functions pipetting, dispensing and titrating, for example, can be set.

(20) Under that, a display 6 is recessed into the front side of the housing 2.

(21) Beneath the display 6, two rocker switches 7, 8 that serve to call up various menu functions and to set parameters project from the front side of the housing 2.

(22) At the height of the rocker switches 7, 8, electrical contacts 9, 10 for charging a battery of an electrical power supply 11 are located on the left and the right side of the housing. The battery is accommodated in the upper part of the housing 2.

(23) Between the two rocker switches 7, 8, a reset button 12 is located in the front of the housing.

(24) In the middle underneath the reset button 12, a trigger button 14 is located above on a curvature 13 on the front side of the housing 2 for triggering sucking and dispensing steps as well as for saving parameter settings. In front of the trigger button 14, an ejector button 15 is located that engages with the curvature 13 that fits snugly downward against the flat front side of the housing 2.

(25) A hook-shaped finger rest 16 projects to the back from the back side of the housing 2.

(26) On the lower end, the housing 2 has a first opening 17 through which a first receiver 18 in the housing 2 for a syringe flange of a syringe cylinder of a syringe is accessible from the outside. According to FIG. 2, above the first receiver 18 a bell-shaped receiving body 19 is located in which a second receiver 20 is arranged that is accessible through a second opening 21 on the underside of the receiving body 19 for inserting a plunger rod end of a syringe plunger of the syringe.

(27) In the first receiver 18, first means for releasably holding the syringe flange are located on a stop 22 in the housing 2 that are designed as a syringe gripping lever 23.

(28) The receiving body 19 has second means for releasably holding in the form of plunger gripping levers 24 that serve to releasably hold the syringe plunger in the second receiver 20.

(29) The attachment of the syringe flange and syringe plunger in the first and second receivers 18, 20 by means of the first and second means for releasably holding can be loosened by actuating the ejector button 15 that works via a gear 25 on the syringe gripping lever 23 and plunger gripping lever 24.

(30) When a syringe is held in the dosing device, the syringe plunger is displaceable by means of a dosing drive 26.

(31) According to FIGS. 3 and 4, the dosing drive 26 comprises a spindle drive 27 that has a threaded spindle 28 and a spindle nut 29.

(32) The threaded spindle 28 has two first flattenings 30.1, 30.2 on both sides that extend in the longitudinal direction and two threaded areas 31.1, 31.2 of an external thread 31 between them. According to FIGS. 4 and 5, the threaded areas 31.1, 31.2 taper in the cross-section in the radial direction to the outside.

(33) Guide ribs 32.1, 32.2 project to the outside from the first flattenings 30.1, 30.2. According to FIGS. 4 and 5, the guide ribs 32.1, 32.2 have two flattenings 33.1, 33.2 on the outer end. Next to these, they have guide areas 34.1, 34.2, 34.3, 34.4, the distance of which from the central axis of the threaded spindle 28 corresponds to half of the core diameter of an internal thread 35 of the spindle nut 29.

(34) According to FIG. 5, the external thread 31 has trapezoid-shaped thread profiles 36.1, 36.2. The outer edges of the thread profiles 36.1, 36.2 in the radial direction are rounded. Furthermore, the transitions of the flanks 37.1, 37.2 of the thread profiles 36.1, 36.2 are rounded on both sides to the core of the threaded spindle 28. Finally, the side edges of the thread profiles 36.1, 36.2 that are delimited by the first flattenings 30.1, 30.2 are rounded.

(35) The outer edges of the guide ribs 32.1, 32.2 and the transitions of the guide ribs 32.1, 32.2 to the first flattenings 30.1, 30.2 are also rounded.

(36) The threaded spindle 28 is injection molded so that the parting plane of the two halves of the injection molding tool falls in the second flattenings 33.1, 33.2. The roundings of the guide ribs 32.1, 32.2 and of the thread profiles 36.1, 36.2 are advantageous for the filling of the injection molding mold and the demolding of the molded part from the injection molding tool. The roundings of the profiles 36.1, 36.2 and of the guide areas 34.1, 34.2, 34.3, 34.4 are moreover advantageous for the low-friction and low-wear shifting of the threaded spindle 28 in the spindle nut 29.

(37) According to FIG. 4, the spindle nut 29 has a central hollow shaft 38, on the inner circumference of which the internal thread 35 is designed. The internal thread 35 extends continually over a first section of the sleeve. The thread profile of the internal thread 35 is also trapezoid-shaped, wherein the radially inner ends of the profile are rounded and the transitions between the flanks of the profile as well.

(38) A circular collar 39 that is designed as a toothed belt wheel 40 with teeth 41 on the circumference sits on the hollow shaft 38. The hollow shaft 38 projects from the circular collar 39 to both sides.

(39) The external thread 31 of the threaded spindle 28 and the internal thread 35 of the spindle nut 29 are coordinated with each other so that the threaded spindle 28 can be screwed into the spindle nut 29.

(40) According to FIGS. 6 and 7, the guide areas 34.1 to 34.4 internally abut each turn of the internal thread 35 of the spindle nut 29.

(41) A clearance fit occurs between them.

(42) The dosing drive 26 further comprises, according to FIG. 3, an electric drive motor 42 that supports a further toothed belt wheel 44 on a motor shaft 43. The spindle nut 29 is rotatably mounted on the hollow shaft 38 in two bearing bushings 45 and is held in two parallel holding plates 46 of a holder 47 at a defined distance from each other and from the drive motor 42. The holder 47 has bearing eyes 48 for fixing in the housing 2.

(43) A toothed belt 49 is placed around the toothed belt wheels 40, 44 in order to transfer the rotation of the motor shaft 43 to the spindle nut 29.

(44) Furthermore, the dosing drive 26 comprises peg-shaped first guide elements 50.1, 50.2 that project from the receiving body 19 to the outside in opposite directions. According to FIG. 2, the first guide elements 50.1, 50.2 work together with guideways between bar-shaped second guide elements 51.1, 51.2 on the inner sides of the housing hulls 3, 4. The threaded spindle 28 is hereby hindered from a rotation in the housing 2 and the receiving body 19 is guided in the axial direction of the threaded spindle 28.

(45) Furthermore, an electric control apparatus 52 arranged in the upper area of the housing belongs to the dosing drive 26. The control apparatus 52, the electric drive motor 42 and the remaining electronic components of the dosing device are fed from the electrical power supply 11.

(46) By applying current to the drive motor 42, the motor shaft 43 and therefore the spindle nut 29 are set in rotation and the threaded spindle 28 is axially displaced. The threaded spindle 28 is hereby guided on the guide areas 34.1 to 34.4 in the internal thread 35. Due to the symmetrical arrangement of the guide areas 34.1 to 34.4, a very even running of the threaded spindle 28 is achieved.

(47) The threaded spindle 28 and the spindle nut 29 are produced from plastics and/or metal. Preferably, high-performance plastics and/or engineering plastics are used for this. For example, the threaded spindle 28 and the spindle nut 29 are each made of PEEK.

(48) The electronic manual dosing device 1 according to FIGS. 8 and 9 is an electronic manual pipette. It has an upper housing part 53 in the form of a hand grip and a substantially cylindrical lower housing part 54. The upper housing part 53 contains a drive unit and the lower housing part 54 contains a displacement unit composed of a cylinder 55 and a plunger 56 that is movable therein that can be displaced by means of the drive unit.

(49) The upper housing part 53 has a substantially cylindrical trunk section 57 and a box-shaped head section 58 that with the trunk section 57 encloses an obtuse angle. The head section has a selection wheel 5 on the front side on the upper end for selecting the respective operating mode, for example pipetting, dispensing, pipetting and mixing, reverse pipetting, multiple receiving, sequential dispensing.

(50) Under the selection wheel 5, a display 6 is recessed into the front side of the head section 58.

(51) Underneath the display 6, there is a rocker button 59 in the middle for controlling the receiving and discharge of liquid and setting parameters. To both sides of the rocker button 59, there are further buttons 60 for selecting various menu functions and setting parameters.

(52) Underneath the rocker button 59, an ejector button 15 for controlling the ejection of pipette tips 61 is located on the front side in the transition area between the head section 58 and trunk section 57. The ejector button 15 is connected to an ejector rod that extends in the trunk section 57 to the lower end of same.

(53) A hook-shaped finger rest 16 projects to the back from the back side of the head section 58.

(54) At the height of the display 6, electrical contacts 9, 10 for charging a battery of an electrical power supply 11 accommodated in the head section 58 are located on the left and the right side of the head section 58. The battery is connected to an electric control apparatus 52 accommodated in the head section 58. The electric control apparatus 52 is connected to the rocker button 59 and the further buttons 60, a sensor for detecting the rotational position of the selection wheel 5, and a drive motor 42 of a dosing drive 26.

(55) The trunk section 57 has a hollow space 62 in which the dosing drive 26 is arranged at the top which will be explained in greater detail below. The trunk section 57 has a lower housing opening 63 on the lower end, through which the lower housing part 54 is inserted with its upper end into the hollow space 62 of the trunk section 57. In the inserted position, the lower housing part 54 is releasably connected to the upper housing part 53 by means for releasably connecting the lower housing part 54 and the upper housing part 53. According to FIG. 10, the means for releasably connecting comprise a locking connection with spring-loaded locking hooks 64 of the lower housing part 54 that are lockable in the hollow space 62 behind locking edges of the upper housing part 53. The locking can be intentionally reversed by moving an unlocking sleeve 65 guided on the outside of the lower housing part 54.

(56) According to FIG. 11, the lower housing part 54 has the cylinder 55 at the top with the plunger 56 that can be displaced within it in the longitudinal direction and is guided in a sealing manner. The cylinder 55 is designed as a bushing (liner) that is held in a cylinder section 66 of the lower housing part 54. The cylinder section is connected at the bottom via a conical connecting section 67 to a tube 68 that has a seal seat 69 on the lower end onto which the pipette tip 61 is clamped. The tube 68 surrounds a connecting channel 70 that connects a first hole 71 on the lower end of the cylinder 55 to a second hole 72 in the seal seat 69 on the lower end of the tube 68.

(57) On the cylinder section 66, the connecting section 67 and the tube 68, an ejector sleeve 72 adapted to the outer shape of same is slid on for forcing off the pipette tip 61 from the seal seat 69. The ejector sleeve 73 is connected at the top to the ejector rod via releasable coupling means of the ejector sleeve 73 and ejector rod. The releasable coupling means consist in a simple case in a clamping seat of the lower end of the ejector rod in a borehole in a side projection on the upper edge of the ejector sleeve 73.

(58) The lower housing part 54 supports at the top a closing cap 74, the cap casing 75 of which is connected to the cylinder section 66 and which has a central upper housing opening 77 in a cap bottom 76.

(59) The plunger 56 is connected to a plunger rod 78 that supports a disk 79 at the top. Between the disk 79 and the upper edge of the cylinder 55, a helical spring 80 is arranged that pushes the disk 79 into a starting position on the underside of the cap bottom 76.

(60) According to FIGS. 9 to 12, the threaded spindle 28 of the dosing drive 26 engages, with its lower end through the upper housing opening 77, with the closing cap 74 and abuts the upper side of the disk 79.

(61) According to FIGS. 12 and 13, the dosing drive 26 largely corresponds to the dosing drive 26 from FIG. 3 so that the embodiments in FIG. 3 correspondingly apply for the features provided with the same reference numbers from FIGS. 12 and 13. In the case of the dosing drive 26 from FIGS. 12 and 13, the lower end of the threaded spindle 28 contacts the disk 79 and is not connected to a bell-shaped receiving body 19. Accordingly, in FIGS. 12 and 13 a guiding of the lower end of the threaded spindle 28 by guide elements 50.1, 50.2 on the receiving body 19 is omitted. Rather, the threaded spindle 28 is guided on the upper end in a guide cylinder 81 that projects from the upper side of the holder 47 for the bearing bushings 45 of the spindle nut 29.

(62) The guide cylinder 81 has two guide grooves 82 on the inner circumference that extend in the longitudinal direction of the guide cylinder 81. The two guide grooves 82 are diametrically opposite each other.

(63) According to FIGS. 10 and 13, the threaded spindle 28 supports a sleeve-shaped guide element 83 on the upper end that has two guide noses 84 projecting to the outside that engage with the guide grooves 82. The guide element 83 is firmly connected to the threaded spindle 28. The guide element 83 linearly guides, for one, into the threaded spindle 28 in the guide cylinder 81 and hinders, for another, a twisting. As a result, the threaded spindle 28 is displaceable by rotating the spindle nut 29 in the longitudinal direction.

(64) By applying current to the drive motor 42, the motor shaft 43 is rotated, the spindle nut 29 is set in rotation via the toothed belt 49, and the threaded spindle 28 is axially displaced. With the downward displacement of the threaded spindle 28 the plunger 56 is pushed farther into the cylinder 55, and with the upward displacement of the threaded spindle 28 it is displaced, since the disk 79 is held by the pretensioned helical spring 80 in abutment on the lower end of the threaded spindle 28. An air column is hereby displaced in the tube 68 that sucks liquid into or expels liquid from the pipette tip 61.

(65) FIG. 14 shows a micrometer gauge 85 that is designed as an outside micrometer. A rigid bracket 86 has a base 87 and two bracket arms 88, 89. Fastened to an inner side of a first bracket arm 88 is a disk-shaped first measuring jaw 90 that has a flat, first contact surface on its free end.

(66) A spindle nut 29 is fastened to a second bracket arm 89. The top part of the spindle nut 29 is cut away in the drawing for better understanding. By its external thread 31, a threaded spindle 28 engages in an internal thread 35 of the spindle nut 29 and forms a spindle drive therewith. The threaded spindle 28 is securely connected on one side to a cylindrical second measuring jaw 91 that has a flat, second contact surface on its free end. On the outer side, the spindle nut has a first scale 92 running in the longitudinal direction with a millimeter division.

(67) On the other side, the threaded spindle 28 is connected by a slip clutch (“touch slide”, not shown) to a measuring sleeve 93. The top part of the measuring sleeve 93 is cut away in the drawing for better understanding. The measuring sleeve 93 has a second scale 94 running in the peripheral direction with a one-hundredth millimeter division.

(68) The threaded spindle 28 and the spindle nut 29 are a spindle drive 27 designed according to the invention. Consequently, the micrometer gauge 85 is economically producible, particularly light, and yields precise measuring results.

REFERENCE SIGN LIST

(69) 1 Electronic manual dosing device 2 Housing 3 Front housing hull 4 Rear housing hull 5 Selection wheel 6 Display 7, 8 Rocker switch 9, 10 Electrical contact 11 Power supply 12 Reset button 13 Curvature 14 Trigger button 15 Ejector button 16 Finger rest 17 First opening 18 First receiver 19 Receiving body 20 Second receiver 21 Second opening 22 Stop 23 Syringe gripping lever 24 Plunger gripping lever 25 Gear 26 Dosing drive 27 Spindle drive 28 Threaded spindle 29 Spindle nut 30.1, 30.2 First flattening 31 External thread 31.1, 31.2 Threaded area 32.1, 32.2 Guide rib 33.1, 33.2 Second flattening 34.1, 34.2, 34.3, 34.4 Guide area 35 Internal thread 36.1, 36.2 Thread profiles 37.1, 37.2 Flanks 38 Hollow shaft 39 Circular collar 40 Toothed belt wheel 41 Teeth 42 Drive motor 43 Motor shaft 44 Toothed belt wheel 45 Bearing bushing 46 Holding plate 47 Holder 48 Bearing eye 49 Toothed belt 50.1, 50.2 First guide element 51.1, 51.2 Second guide element 52 Control apparatus 53 Upper housing part 54 Lower housing part 55 Cylinder 56 Plunger 57 Trunk section 58 Head section 59 Rocker button 60 Button 61 Pipette tip 62 Hollow space 63 Lower housing opening 64 Locking hook 65 Unlocking sleeve 66 Cylinder section 67 Connecting section 68 Tube 69 Seal seat 70 Connecting channel 71 Hole 72 Hole 73 Ejector sleeve 74 Closing cap 75 Cap casing 76 Cap bottom 77 Housing opening 78 Plunger rod 79 Disk 80 Helical spring 81 Guide cylinder 82 Guide groove 83 Guide element 84 Guide nose 85 Micrometer gauge 86 Bracket 87 Base 88 First bracket arm 89 Second bracket arm 90 First measuring jaw 91 Second measuring jaw 92 First scale 93 Measuring sleeve 94 Second scale