Plug-in and securing device for rotor of peristaltic blood pump

Abstract

The invention discloses a drive shaft for a rotor of a peristaltic pump and a rotating unit having the drive shaft and the rotor. The drive shaft is designed for insertion of a rotor of the blood pump, the drive shaft extending along a central axis and having a rotationally symmetrical head on a free end section, the head being delimited by a recess. A tapered or frustoconical sliding section formed by chamfering is arranged on the head. The rotary unit comprises a drive shaft and a rotor inserted on the drive shaft, the rotor comprises a hose roller, the groove comprises a groove edge on the head side, the groove edge is arranged perpendicular to the central axis, a locking element is arranged in the rotor, and the locking element can move transversely to the central axis. The contact section of the locking element is pre-tightened in the direction of the central axis and in the direction of the bottom of the groove. The contact section can be moved in a direction away from the central axis and in a direction away from the bottom of the groove by means of an actuation section which is fastened to the locking element or is integrally formed. The contact surface of the contact section is arranged perpendicular to the central axis.

Description

Technical Field

[0001] The present disclosure relates to a peristaltic blood pump for a medical device for extracorporeal blood treatment. Such a blood pump has a pump housing with a curved, track-shaped running surface and a rotor rotatable in the running surface, wherein a hose segment is inserted between the running surface and the rotor. The rotor can be mounted on a drive shaft of the blood pump with an axle receptacle and is provided with a locking element for axial securing. Such a peristaltic pump is also called a hose roller pump.

[0002] In particular, the present disclosure relates to a drive shaft and a plug-in and safety device of a rotor of such a peristaltic blood pump. Background of the Invention

[0004] In medical equipment for extracorporeal blood treatment (dialysis), peristaltic hose roller pumps are often used, which transport the blood taken out from the patient back to the dialyzer and back to the patient. Here, the circular curved hose segment is abutted against the corresponding curved inner running surface of the pump housing with its outer side. Then, the rotor of the blood pump in the hose segment moves along the hose segment along with the rollers installed thereon, wherein the rollers radially outwardly locally squeeze the hose and therefore utilize the elastic material properties of the hose to produce blood transport through the hose. For this reason, blood is supplied to the hose through a first connector and is again derived through other connectors at the other ends of the hose. Therefore, for example, the hose forms a so-called transmission system together with an introduction line and a derivation line and a plurality of air collectors, and the patient's blood is transported back to the dialyzer and is transported back to the patient using this transmission system. Background Art

[0005] A peristaltic blood pump is known from EP 2682604 A1. The torque is transmitted from the drive shaft to the rotor by a form-locking connection. In addition, the rotor can be removed from the drive shaft in order to be able to replace the hose. For this purpose, the rotor is axially secured on the drive shaft by means of a likewise form-locking snap-in or latching mechanism. An axially acting locking element can be moved by means of a manual and spring-loaded pressure switch, thereby releasing the rotor and enabling it to be removed axially. The switch is positioned so that when the rotor is grasped by an operator of the blood pump or dialysis device, the switch can be pressed down at the same time.

[0006] The placement of the rotor on a non-rotationally symmetrical drive shaft is usually associated with perceptible consequences for the operator of the rotational movement of the rotor, which is forced by the drive shaft. This forced rotational movement of the rotor requires little skill and / or patience from the clinical staff, who are usually under time pressure.

[0007] This disadvantage is overcome in a peristaltic blood pump known by the applicant under the name Dialog+, which has a rotationally symmetrical drive shaft, thereby eliminating the forced rotational movement when the rotor is plugged in. During the operation of the blood pump, the torque is transmitted from the drive shaft to the rotor via a circumferential friction lock on the cylindrical contact area of ​​the outer cover of the drive shaft, thereby also forming a freewheel. In order to release the rotor from the drive shaft, it is necessary to press a switch, which is arranged on the surface of the rotor and whose operating surface ends flush with the housing wall of the rotor located there. The operating surface of the switch and the housing wall there are arranged perpendicular to the drive shaft. Therefore, when the rotor is grasped by the operator, the switch cannot be actuated with the same finger at the same time, and the switch is also used to grasp and remove the rotor.

[0008] In the peristaltic blood pump of the applicant, which is named Dialog+, the rotor and the hose segment are arranged in a bowl-shaped area of ​​the blood pump, in the center of which a rotationally symmetrical drive shaft protrudes from the bottom in a bolt-like manner. The drive shaft has a head and a surrounding groove, which is defined by an edge inclined on the bottom side and by an edge on the head side with the greatest steepness. In other words, the edge on the head side of the groove has the shape of a circular ring, which is oriented perpendicular to the center axis of the drive shaft. When the rotor is loaded with a force away from the bottom in the extraction direction of the rotor and when the operating surface of the switch is not pressed at the same time, the locking element is supported on the edge on the head side.

[0009] A rounding is provided on the head in the transition between the cylindrical cap and the disk-shaped end face, which serves to make it easier to plug on the rotor. Summary of the invention

[0010] The object of the present disclosure is to provide a drive shaft for a peristaltic blood pump and a rotary unit consisting of the drive shaft and a rotor of a peristaltic blood pump, wherein the plugging-in of the rotor is further simplified.

[0011] This object is achieved according to the invention with respect to the drive shaft and with respect to the rotary unit.

[0012] The drive shaft according to the disclosure is arranged and designed to be accommodated by plugging in the rotor of a peristaltic blood pump. The drive shaft extends along its central axis and has a rotationally symmetrical head on a free end section, which is defined by adjacent grooves viewed along the central axis. A conical or truncated-conical sliding section formed by chamfering is arranged on the head. As a result, the installation forces of the rotor are low. As a result, an introduction aid for the rotor is also achieved, which tolerates axial misalignment and non-vertical plug-in movements and avoids hooking of the rotor.

[0013] Preferably, the sliding section extends over 30% to 40%, preferably 35%, of the axial extension (of the length) of the head, viewed along the center axis of the drive shaft.

[0014] Preferably, the sliding section has an angle with the center axis of the drive shaft in the range of 5° to 20°, in a specific embodiment of 15°.

[0015] On the side of the chamfer or the sliding section facing away from the groove, the entire end face of the drive shaft can be spherical. Alternatively, the head of the drive shaft can have an end face, wherein the transition from the chamfer or the sliding section to the end face is rounded with a radius of preferably more than 1 mm, in the specific embodiment 1.5 mm. In both cases, the insertion of the rotor is further simplified and hooking is avoided.

[0016] A cylindrical head section (known per se from the prior art) is preferably provided between the chamfer or sliding section and the groove, which, viewed along the center axis of the drive shaft, preferably extends over 15% to 25% of the axial extension (length) of the head, in a specific embodiment 20%.

[0017] The transition from the sliding section to the cylindrical head section is preferably rounded with a radius of preferably between 2 and 6 mm, in the specific embodiment 4 mm, thereby further simplifying the insertion of the rotor and avoiding hooking.

[0018] With the above-described design of the drive shaft, keyless plug-in of the rotor can be achieved in a relatively small installation space.

[0019] The transition from the cylindrical head section to the groove is preferably rounded with a radius of preferably between 0.1 and 0.3 mm, in the specific embodiment 0.25 mm. This rounding serves primarily to make removal of the rotor easier, so that the rotor is less likely to get caught during removal. The rounding is relatively small and therefore does not have a significant effect on the undercut of the locking element.

[0020] In a preferred development of the drive shaft, a cylindrical contact area of ​​a friction-locking coupling or for a friction-locking coupling is formed on the side of the groove facing away from the head. The groove edge on the drive side arranged between the groove bottom and the cylindrical contact area of ​​the groove is inclined conically or truncated cone-shaped relative to the center axis. The transition from the groove edge to the cylindrical contact area is rounded with a radius preferably between 1.5 and 4 mm, in a specific embodiment 2 mm. This makes it possible to easily guide the fit in the rotor that serves as a bearing point through this position and the rotor will not get caught when plugged in.

[0021] Particularly preferably, the head, the groove and the contact area for the friction-locking drive are rotationally symmetrical. This enables the rotor to be plugged onto the shaft at any position and does not have to first find the correct rotational position.

[0022] The rotary unit according to the present disclosure is designed for a peristaltic blood pump and has the above-mentioned drive shaft and a rotor with a hose roller, which is plugged or can be plugged onto the drive shaft. The groove has a groove edge facing the head and is therefore called the head side, which is arranged perpendicular to the central axis and therefore preferably has a circular ring shape with maximum steepness. A locking element is arranged in the rotor, which can move transversely to the central axis of the drive shaft. The contact section of the locking element is radially preloaded in the direction of the central axis and in the direction of the groove bottom by means of a spring, wherein the contact section can be moved radially and in a direction away from the central axis and in a direction away from the groove bottom by means of an operating section that is fastened to the locking element or formed integrally. At least one contact surface of the contact section or the entire contact section is arranged perpendicular to the central axis like the groove edge on the head side. When the rotor is loaded with a force in the direction of extension of the rotor away from the bottom of the housing and when it does not press on the actuating section, the rotor is securely held during operation of the blood pump due to the vertical orientation of the groove edge on the head side on the one hand and the contact surface of the contact section on the other hand.

[0023] The actuation section can be, for example, an actuation surface, but it can also have a different shape, for example a spherical shape.

[0024] The contact section is preferably arranged on the side of the drive shaft opposite the actuating section. Pressing the actuating section against the drive shaft then results in an extension of the contact section on the other side of the drive shaft. For this purpose, a bridging section is required on the locking element, which preferably extends along the drive shaft on one side and connects the actuating section preferably in one piece to the contact section.

[0025] If the spring is a compression spring, it is also arranged on the side of the drive shaft that is opposite the actuation section.

[0026] In a particularly preferred embodiment of the locking element, the contact section is arc-shaped and extends in the circumferential region of the groove. The contact section preferably extends along the circumference of the groove over 80° to 96°. With increasing extension in the direction of the actuating section, the path of the entire locking element becomes longer, which is necessary to move its contact section completely out of the groove. This increases the safety against accidental unlocking of the rotor.

[0027] In a simple design scheme in terms of device technology, the locking element together with the operating section, the bridging section and the contact section are stamped sheet metal parts. Here, the operating section can be formed by bending or folding, for example, 90°.

[0028] In a preferred embodiment, the distance between the actuating section and the drive shaft is smaller than the housing section of the rotor surrounding the actuating section. The actuating section is thus sunk into the housing section of the rotor and the safety against unintentional pressing and thus unlocking of the rotor is increased.

[0029] In a preferred embodiment, the spring causes a release force, i.e. an actuation force of at least 10 N on the actuating element starting from the locked position. This increases the safety against accidental unlocking of the rotor compared to the prior art. As the release force increases, the finger force required to completely move the contact section out of the recess increases. This further increases the safety against accidental unlocking of the rotor.

[0030] The removal force of the rotor 1 is at least 12N. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 is a peristaltic blood pump with a rotating unit according to an embodiment of the present disclosure;

[0032] Figure 2 yes Figure 1 A cross-sectional view of a rotating unit in FIG.

[0033] Figure 3 Another cross-sectional view shows Figure 1 A cutout of a rotating unit in FIG. 1 , having two variants of the contact section;

[0034] Figure 4 is a view of the portion of the drive shaft from the previous figures that is important for the present disclosure.

[0035] Among them: 1-rotor; 2-drive shaft; 3-head; 4-roller; 6-compression spring; 8-running surface; 10-locking element; 12-operating section; 14-housing section; 16-through recess; 18-coupling section; 20-rest area (of drive shaft); 22-rest section (of locking element); 24-groove; 25-central axis; 26-(optional) enlargement of the rest section (of locking element); 28-spring; 30-sliding section; 32-transition section / radius; 34-transition section / radius; 36-cylindrical head section; 37-groove edge on the head side; 38-transition section / radius; 40-groove edge on the drive side; 42-transition section / radius. DETAILED DESCRIPTION

[0036] Embodiments of a rotary unit having embodiments of a drive shaft are described below based on the drawings.

[0037] Figure 1 The invention is a peristaltic blood pump with a rotating unit according to an embodiment of the present disclosure. The rotating unit has a rotor 1 and a pin-shaped drive shaft 2. Figure 1 Only the head 3 of the drive shaft can be seen.

[0038] The rotor 1 has two rollers 4 distributed on its circumference, which are tensioned outwardly in the direction of a track-shaped running surface 8 which is in the form of a circular arc at least in the middle region by the force of corresponding compression springs 6. A hose section of a hose (not shown) rests on the running surface 8. The blood to be transported is transported through the hose section resting on the running surface 8, wherein the rollers 4 are pressed into the hose section and the pressed position moves along the hose section as a function of the rotation of the rotor 1.

[0039] Because in Figure 1 The housing cover of the middle rotor 1 is removed so that the head 3 of the drive shaft 2 can be seen. The rotor 1 is held on the drive shaft 2 in the axial direction by a locking element 10 designed as a locking plate. This has an actuating section 12 designed as an actuating surface, which is arranged radially inside the housing section 14 of the rotor 1. The actuating section 12 can be pressed by an operator through a through recess 16 in the housing section 14 in order to release the axial locking and remove the rotor 1 from the drive shaft 2.

[0040] Figure 2 yes Figure 1 The rotor 1 is connected in a rotationally fixed manner in the conveying direction via a friction-locking coupling 18 to a cylindrical contact region 20 of the drive shaft 2 , while a freewheel is present in the opposite direction.

[0041] The locking element 10 is manufactured in one piece as a stamped and bent sheet metal part and has a contact section 22 which is embedded in a circumferential groove 24 of the drive shaft 2 which is rotationally symmetrical with respect to the central axis 25 in order to prevent the rotor 1 from being pulled out axially (at Figure 2 center upward).

[0042] The locking element 10 has an actuating section 12 produced by bending, which is designed as an actuating surface and which can also be considered a button. The actuating section 12 is radially retracted relative to the housing section 14. This prevents unintentional actuation and thus release of the rotor 1. The actuating section 12 is oriented approximately parallel to the center axis 25. Therefore, the finger for releasing the rotor 1 can also be used to remove the rotor 1 with one hand. The through recess 16 in the housing section 14 also serves to securely hold the finger on the rotor 1.

[0043] Figure 3 The cross section through the drive shaft 2 is shown Figure 1 In particular, the main body section of the locking element 10 is shown in the view (from below), and the actuating section 12 is presented in section in the form of its angled transition to the main body section of the locking element 10 .

[0044] The locking element 10 grips the drive shaft 2 on one side, in other words, the locking element 10 has a section-shaped concave recess in which the drive shaft 2 is arranged. A circular arc-shaped contact section 22 is formed at the edge of the recess, which is tensioned in the direction of the groove 24 of the drive shaft 2 by means of a spring 28. The spring 28 is arranged on the side opposite to the operating section 12 with respect to the drive shaft 2 and is configured as a compression spring. The spring 28 causes a disengagement force of at least 10N on the operating element 12 and a removal force of at least 12N for the rotor 1. Therefore, a high degree of safety is provided to prevent accidental unlocking and loosening of the rotor 1.

[0045] A smaller variant of the contact section 22 is shown in solid lines. This variant or the contact section 22 extends about the groove 24 or the drive shaft 2 over approximately 82°.

[0046] If an optional enlargement 26 (indicated by dashed lines) is provided on the contact section 22, the path required for moving out of the contact section 22 can be increased. This variant extends approximately 90° around the groove 24 or the drive shaft 2.

[0047] Figure 4 1 is a view showing a portion of the drive shaft 2 from the previous figure, onto which the rotor 1 is plugged. This portion of the drive shaft 2 extends along its center axis 25 and has a head 3 at the free end section, which is defined by the adjacent groove 24 viewed along the center axis 25. A conical or truncated-conical sliding section 30 formed by chamfering is arranged on the head 3. As a result, the installation forces of the rotor 1 are low. This also provides an introduction aid for the shaft receptacle of the rotor 1, which tolerates axial misalignment and non-vertical plug-in movements and avoids hooking of the rotor 1.

[0048] Viewed along the central axis 25 of the drive shaft, the sliding section 30 extends over approximately 35% of the axial extension (length) of the head 3 and has an angle of 15° with the central axis 25 of the drive shaft 3 .

[0049] On the side of the chamfer facing away from the groove 24, the head 3 has an end face, wherein the transition from the chamfer or sliding section 30 to the end face is rounded with a radius 32 of approximately 1.5 mm. This further simplifies the insertion of the rotor 1 and avoids hooking.

[0050] A cylindrical head section 36 is provided between the chamfer or sliding section 30 and the groove 24, which, viewed along the center axis 25 of the drive shaft 2, extends over approximately 20% of the axial extension (length) of the head 3. The transition from the sliding section 30 to the cylindrical head section 36 is rounded with a radius 34 of 4 mm. This further simplifies the insertion of the rotor 1 and avoids hooking.

[0051] The transition from the cylindrical head section 36 to the head-side groove edge 37 of the groove 24 is rounded with a radius 38 of 0.25 mm. This rounding 38 serves primarily to make the removal of the rotor 1 easier, so that the rotor is less likely to get caught during removal. The rounding or radius 38 is relatively small and therefore does not have a significant effect on the undercut of the locking element 10.

[0052] The cylindrical contact area 20 of the friction-locking coupling 18 is formed on the side of the groove 24 facing away from the head 3. The drive-side groove edge 40 arranged between the groove base of the groove 24 and the cylindrical contact area 20 is inclined conically or truncated-conically relative to the center axis 25. The transition 42 from the groove edge 40 to the cylindrical contact area 20 is rounded with a radius 42 of 2 mm. This makes it possible to easily guide the fit serving as a bearing point in the rotor 1 through the transition 42 and the rotor 1 will not get caught when plugged in.

[0053] In general, the above embodiments show peristaltic pumps whose drive shaft 2 is rotationally symmetrical, so that the rotor 1 to be plugged in can be plugged in without pressure onto the actuation section 12 and without maintaining a predetermined rotational position. Deviations from the ideal plug-in direction are also tolerated at the head 3 of the drive shaft 2 due to the conical or truncated-conical sliding section 30 formed by chamfering.

[0054] In order to prevent the rotor 1 from accidentally coming loose from the drive shaft 2, at least one of the following measures can be provided in addition:

[0055] The actuating section 12 (button) is lowered relative to the housing section 14 of the rotor 1 .

[0056] The spring 28 is designed such that the actuating section 12 has a release force of 10N.

[0057] The contact section 22 (with its contact surface for the groove rim on the head side) extends on a circular arc through 90° around the groove 24 .

Claims

1. A drive shaft (2) for a peristaltic blood pump, the drive shaft being arranged and designed to be plugged into a rotor (1) of the blood pump, wherein: The drive shaft (2) extends along a center axis (25) and has a rotationally symmetrical head (3) at a free end section, the head being defined by a groove (24), wherein the groove (24) preferably has a groove edge (37) on the head side, the groove edge being arranged perpendicular to the center axis (25), characterized in that a conical or truncated-conical sliding section (30) formed by chamfering is arranged on the head (3).

2. The drive shaft (2) according to claim 1, characterized in that Viewed along the center axis (25), the sliding section (30) extends over 30% to 40% of the axial extension of the head (3).

3. The drive shaft (2) according to claim 1 or 2, characterized in that: The sliding section (30) has an angle of 5° to 20° relative to the center axis (25) of the drive shaft (2).

4. The drive shaft (2) according to any one of claims 1 to 3, wherein: The head (3) has an end face, characterized in that the transition (32) from the end face to the sliding section (30) is rounded, preferably with a radius (32) greater than 1 mm.

5. The drive shaft (2) according to any one of claims 1 to 4, characterized in that A cylindrical head section (36) is arranged between the sliding section (30) and the groove (24).

6. The drive shaft (2) according to claim 5, characterized in that The cylindrical head section (36) extends in the range of 15% to 25% of the axial extension of the head (3), viewed along the center axis (25) of the drive shaft (2).

7. The drive shaft (2) according to claim 5 or 6, characterized in that The transition (34) from the sliding section (30) to the cylindrical head section (36) is preferably rounded with a radius (34) in the range of 2 to 6 mm.

8. The drive shaft (2) according to any one of claims 5 to 7, characterized in that The transition (38) from the cylindrical head section (36) to the recess (24) is preferably rounded with a radius (38) in the range of 0.1 mm to 0.3 mm.

9. The drive shaft (2) according to any one of claims 1 to 8, wherein: A cylindrical abutment area (20) is formed on the side of the groove (24) facing away from the head (3), wherein a groove edge (40) on the drive side arranged between the groove bottom and the cylindrical abutment area (20) is conical or truncated cone-shaped, characterized in that a transition (42) from the groove edge (40) on the drive side to the cylindrical abutment area (20) is preferably rounded with a radius (42) in the range between 1.5 and 4 mm.

10. A rotary unit for a peristaltic blood pump, comprising a drive shaft (2) according to any one of claims 1 to 9 and a rotor (1) plugged or pluggable onto the drive shaft, the rotor having a hose roller (4), wherein: The groove (24) has a groove edge (37) on the head side, which is arranged perpendicular to the center axis (25), and wherein a locking element (10) is arranged in the rotor (1), the locking element can move transversely to the center axis (25), and the contact section (22) of the locking element is prestressed in the direction of the center axis (25) and in the direction of the groove bottom by means of a spring (28), wherein the contact section (22) can be moved in a direction away from the center axis (25) and in a direction away from the groove bottom by means of an operating section (12) fastened to the locking element (10) or formed integrally, characterized in that the contact surface of the contact section (22) is arranged perpendicular to the center axis (25).

11. The rotating unit according to claim 10, characterized in that The contact section (22) is arranged on a side of the drive shaft (2) that is opposite the actuating section (12).

12. The rotating unit according to claim 11, characterized in that The contact section (22) is arc-shaped and preferably extends over 75° to 95° in the circumferential region of the groove (24).

13. The rotating unit according to any one of claims 10 to 12, characterized in that The distance between the actuating section (12) and the drive shaft (2) is smaller than a housing section (14) of the rotor (1) surrounding the actuating section (12).

14. The rotating unit according to any one of claims 10 to 13, characterized in that Starting from the locked position, the locking element (10) has a disengagement force of at least 10N.

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