EP3669992B1 - Connection structure - Google Patents

Description

The present invention relates to a connecting structure between a centrifuge rotor and a drive shaft of a centrifuge motor according to the preamble of claim 1.

Centrifuge rotors are used in centrifuges, particularly laboratory centrifuges, to separate the components of samples centrifuged therein by utilizing mass inertia. Increasingly higher rotation speeds are used to achieve high demixing rates. Laboratory centrifuges are centrifuges whose centrifuge rotors preferably operate at at least 3,000, preferably at least 10,000, in particular at least 15,000 revolutions per minute and are usually placed on tables. In order to be able to place them on a work table, they have a form factor of less than 1 m x 1 m x 1 m, so their installation space is limited. The device depth is preferably limited to a maximum of 70 cm. However, laboratory centrifuges are also known that are designed as floor-standing centrifuges, i.e. have a height in the range of 1 m to 1.5 m, so that they can be placed on the floor of a room.

Such centrifuges are used in the fields of medicine, pharmacy, biology and chemistry.

The samples to be centrifuged are stored in sample containers and these sample containers are rotated by the centrifuge rotor. The centrifuge rotors are usually set in rotation by means of a vertical drive shaft that is driven by an electric motor. The coupling between the centrifuge rotor and the drive shaft is usually made by means of the hub of the centrifuge rotor.

There are various centrifuge rotors that are used depending on the application. The sample containers can contain the samples directly or the sample containers can have their own sample containers that contain the sample, so that a large number of samples can be centrifuged simultaneously in one sample container. In general, centrifuge rotors are known in the form of fixed-angle rotors and swing-out rotors and others.

The connecting structure between these centrifuge rotors and the drive shafts of the centrifuge motors, which ensures the locking of the respective centrifuge rotor on the drive shaft during operation of the centrifuge, is usually designed universally, regardless of the type of centrifuge rotor, so that different types of centrifuge rotors can be used without any problems in the same centrifuge.

Such connection structures are usually designed in such a way that there is a screw connection between the centrifuge rotor and the shaft, which makes it possible to create a very secure and durable connection. To lock and release the connection, a key is required to operate the screw connection. The disadvantage of this connection structure is that the key requires additional elements that can be misplaced, and one-handed operation is not possible.

However, it is also already known to use an automatic locking mechanism that allows one-handed operation. This system is marketed, for example, by Sigma Laborzentrifugen GmbH, An der Unteren Söse 50, 37520 Osterode am Harz, under the name "G-Lock ^® ". The disadvantage of this, however, is that a complex redirection of centrifugal forces acting on eccentric elements takes place on coupling elements, which can be subject to numerous errors both during locking and unlocking, which can ultimately make the operation of this coupling device unsafe in everyday life. DE 10 2008 045 556 A1 discloses a connecting construction according to the preamble of claim 1. WO 2011/001729 A1 discloses a connecting construction that, in case of a malfunction, can be unlocked with a separate tool.

It is therefore the object of the present invention to at least partially overcome the disadvantages of the known constructions. Preferably, one-handed operation should be enabled, for which no additional tools are required. In particular, the connecting structure should be designed in such a way that locking is always ensured, whereby jamming or blocking of locking elements cannot occur.

This object is achieved with the connection construction according to the invention according to claim 1. Advantageous further developments are specified in the subclaims and in the following description together with the figures.

The connecting structure according to the invention is designed in such a way that an actuating means is provided on one of the drive shaft and centrifuge rotor elements, which makes the locking releasable, because this enables genuine one-handed operation and the actuating means also effectively prevent jamming or the like of the locking elements.

The connection structure according to the invention between a centrifuge rotor and a drive shaft of a centrifuge motor extending along a shaft axis, wherein a first locking element is arranged on one of the elements centrifuge rotor and drive shaft and a second locking element is arranged on the other of the elements centrifuge rotor and drive shaft, wherein the first locking element is in engagement with the second locking element in the locked state of the connection and is not in engagement in the unlocked state, is thus designed such that an actuating means is present on one of the elements centrifuge rotor and drive shaft, the actuation of which causes the first locking element to disengage from the second locking element, whereby the centrifuge rotor can be removed from the drive shaft.

According to the invention, it is provided, among other things, that the first locking element is a lever. This makes locking particularly easy. Because the lever arm of the lever can move in a plane parallel to the shaft axis, the connecting structure can be made particularly slim. This is all the more true if the lever arm can move in a plane that includes the shaft axis. The term "lever arm" is understood to mean the part of the lever that locks with the second locking element.

In an advantageous further development, the lever is mounted so that it can pivot around an axis. This makes the lever function particularly easy to implement. In an advantageous development, it is provided that the first connecting means has at least one bevel that serves as a locking aid, wherein the bevel preferably lies parallel to the longitudinal extension of the lever. This makes it particularly easy to lock the connecting structure because the first locking means does not represent an obstacle when the centrifuge rotor is attached to the drive shaft.

In an advantageous further development, the first locking element is designed in such a way that it engages with the second locking element due to centrifugal force. This means that locking takes place automatically when the centrifuge is operating.

Alternatively or additionally, it can be provided that the first locking element is pre-tensioned in the direction of engagement with the second locking element. This means that locking can take place without centrifugal force, i.e. automatically, regardless of the operating state of the centrifuge. At the same time, the pre-tension can also serve as a pre-tension for the actuating means, although a separate pre-tension is preferably provided for the actuating means. If the pre-tension is used in addition to the centrifugal force, then the rotation of the centrifuge rotor reinforces the locking by the centrifugal force.

In an advantageous development, it is provided that the first locking element is arranged on the centrifuge rotor. This allows the essential elements to be arranged in the centrifuge rotor, preferably its hub, which improves durability because the drive shaft itself does not have to have any moving parts for the connecting structure. It is then advantageously provided that there are at least two first locking elements, preferably three first locking elements. This makes the locking particularly secure.

In an advantageous further development, the second locking element is a projection of the drive shaft, which the first locking element engages behind in the locked state. This makes the connecting structure particularly simple.

According to the invention, it is provided that the actuating means has a contact surface for a counter-contact surface of the first locking element, wherein the contact surface has an inclined course in the actuating direction of the actuating means, at least in the locked state of the connecting structure, such that actuation of the actuating means causes pivoting of the first locking element.

This makes unlocking particularly easy.

Furthermore, the invention provides that the contact surface runs at an angle in the axial direction of the shaft axis. This means that, for example, levers arranged to pivot about an axis can be unlocked very easily. The counter-contact surface will then ideally run straight in the direction of the shaft axis, but can also have an incline, which must, however, be dimensioned such that an unlocking force is exerted on the first locking element when the actuating means is moved in the actuating direction.

In an advantageous further development, the actuating means is designed as a push button that is pre-tensioned against the actuating direction. This makes unlocking particularly easy and ergonomic.

In an advantageous further development, the actuating means is located on the centrifuge rotor. This allows the drive shaft to be made compact. Alternatively, however, the actuating means could also be located on the drive shaft.

In an advantageous further development, the connecting structure provides a snap-in connection, with the locking being carried out as part of a clip connection that is designed to be detachable. This makes the locking particularly secure and the user can easily understand the security that has been achieved by means of the snap-in sound. To provide the snap-in connection, the first connecting element would preferably be pre-tensioned in the direction of engagement with the second locking element. On the other hand, the center of gravity of the first locking element could be arranged in such a way that the snap-in occurs automatically when the centrifuge rotor is placed on the drive shaft.

Fig. 1

die erfindungsgemäße Verbindungskonstruktion in einer bevorzugten Ausgestaltung im entriegelten und getrennten Zustand im Schnitt,

Fig. 2

die Verbindungskonstruktion nach Fig. 1 im verriegelten Zustand im Schnitt,

Fig. 3

die Verbindungskonstruktion nach Fig. 1 im entriegelten Zustand im Schnitt,

Fig. 4

die Nabe des Zentrifugenrotors der Verbindungskonstruktion nach Fig. 1 in einer perspektivischen Ansicht im Schnitt,

Fig. 5

die Antriebswelle des Zentrifugenrotors der Verbindungskonstruktion nach Fig. 1 in einer perspektivischen Ansicht,

Fig. 6

die Verbindungskonstruktion nach Fig. 1 in Detailansicht im Schnitt und

Fig. 7

eine Laborzentrifuge mit der erfindungsgemäßen Verbindungskonstruktion nach Fig. 1.

The features and further advantages of the present invention will become clear below from the description of preferred embodiments in conjunction with the figures. These show purely schematically:

Fig. 1

the connecting construction according to the invention in a preferred embodiment in the unlocked and separated state in section,

Fig. 2

the connection structure according to Fig. 1 in the locked state in section,

Fig. 3

the connection structure according to Fig. 1 in the unlocked state in section,

Fig. 4

the hub of the centrifuge rotor of the connecting structure according to Fig. 1 in a perspective view in section,

Fig. 5

the drive shaft of the centrifuge rotor of the connecting structure according to Fig. 1 in a perspective view,

Fig. 6

the connection structure according to Fig. 1 in detailed view in section and

Fig. 7

a laboratory centrifuge with the connection construction according to the invention Fig. 1 .

In the Fig. 1 to 6 the connecting structure 100 according to the invention is shown in a preferred embodiment in various views.

It can be seen that the connecting structure 100 between a centrifuge rotor 102 (only partially shown) and a drive shaft 104 (only partially shown) of a centrifuge motor (not shown) has three levers 106 as first locking elements 106, each of which is pivotably mounted about axes 108.

These axes 108 are arranged in the hub 110 of the centrifuge rotor 102 such that the levers 106 extend concentrically around a receiving space 112 for the drive shaft 104, with an angular distance of 120° each.

The levers 106 each have a first lever arm 114 and a second lever arm 116, which are arranged opposite the axis 108, wherein a hook 118 pointing towards the shaft axis W is arranged on the first lever arm 114.

The receiving space 112 for the drive shaft 104 has an incorporated hexagon socket 120, which corresponds to a corresponding hexagon socket 122 of the drive shaft 104 and serves to transmit torque. This hexagon socket 120 is preferably made of a harder material than the hub 110 and is fixed in this hub 110, for example screwed in or shrunk in.

The transmission of the torque from the drive shaft 104 to the centrifuge rotor 102 thus takes place via a positive connection 120, 122. As an alternative to the hexagonal design shown, another polygonal design, for example an octagonal design, could also exist, or the positive connection could be made by a spring-groove connection or a driving pin-groove connection or other positive connections that allow torque transmission.

In addition, the hub 110 has an inner cone 124 that corresponds to a conical section 126 of the drive shaft 104 and serves to ensure the perfectly aligned seat of the centrifuge rotor 102 on the drive shaft 104 and to provide a frictional connection. This inner cone 124 merges into an inner cylinder 128 that is formed by a bearing block 130 that is screwed to the hub 110 and has arms 131 on which the axes 108 are arranged. This bearing block 130 could also have preloading means, for example in the form of springs (not shown), that cause the first lever arms 114 with the hooks 118 to be preloaded toward the shaft axis W. However, in the embodiment shown, such separate preloading means are not provided.

The drive shaft 104 has a groove 132 with an upper projection 134 above the conical section 126, with a chamfer 136 extending above the upper projection 134. This projection 134 forms the second locking element.

It can also be seen that the groove 132 has a peripheral design in the form of an external hexagon 137, which is aligned parallel to the external hexagon 122. As a result, each hook 118 is always parallel to a surface of the external hexagon 137 assigned to it.

The hooks 118 have bevels 138 that are oriented toward the inner cone 124. In the locked state, the hooks 118 engage in the groove 132 and engage behind the upper projection 134.

Furthermore, the hub 110 has a cylindrical cavity 140 above the bearing block 130, which is limited at the top by a cover-shaped closure element 142. In this closure element 142, which can be screwed 143 into the hub 110, for example, there is an opening 144 in which the actuating element 146 is received in a slidingly displaceable manner.

The actuating element 146 has a body 148 designed as a push button 148, which has a collar 150 in its lower section, which projects radially outward and rests against the closure element 142 when the actuating element 146 is not pressed in.

A projection 152 is arranged below the collar 150, wherein at the transition between the body 148 and the projection 152, opposite the collar 150, there is a section 154 with a conical inner contour, which acts as a contact surface that corresponds to a counter contact surface 156 of the lever 106.

The bearing block 130 has an elevation 158 through the outriggers 131 to form a recess 160 (cf. Fig. 2 ). A spiral spring 162 is arranged in this recess 160 on the one hand and between the projection 152 and the outer circumference of the cavity 140 on the other hand and biases the actuating element 146 in an upward direction, i.e. opposite to the actuating direction B of the actuating element 146. The spiral spring 162 thus provides an automatic return of the actuating element 146 from the actuated to the non-actuated state.

It is in Fig. 3 It can also be seen that the opening 144 has a section 164 with a conical inclination, which corresponds to a conical counter-section 166 of the actuating element 146. This effectively prevents the actuating element 146 from tilting when it is moved by the spiral spring 162 against the actuating direction B.

This connection structure 100 now works as follows:
In in Fig. 1 In the state shown, the centrifuge rotor 102 is placed with its hub 110 onto the drive shaft 104 of the centrifuge motor. The hooks 118 with their bevels 138 come into contact with the bevel 136 of the drive shaft 104, whereby the first lever arm 114 is deflected outwards relative to the shaft axis W until the hooks 118 engage in the groove 132 and thereby engage behind the upper projection 134 (cf. Fig. 2 ). The two bevels 136, 138 thus provide a locking aid by preventing the hooks 118 from jamming or snagging on the drive shaft 104.

In order to ensure that engagement occurs before the centrifuge rotor 102 is operated, the center of mass M of the levers 106 is located outside and above in relation to the axes 108, whereby gravity causes the hooks 118 to engage in the groove 132.

The initial position of the levers 106 is limited by the conical inner surface 154 of the actuating element 146. As a result, the second lever arms 116 cannot tilt outwards and prevent the centrifuge rotor 102 from being placed on the surface. Tilting inwards is also not a problem, since the drive shaft 104 pushes these levers 106 back into the correct position when the centrifuge rotor 102 is placed on the surface. However, tilting inwards could also be prevented by designing appropriate contact points in the bearing block 130 (not shown).

When the centrifuge rotor 102 is in operation, the center of gravity of the levers 106 arranged above the axis 108 causes the second lever arms 116 to shift outwards, whereby the hooks 118 are pressed firmly into the groove 132 and the locking is thus carried out securely. There is only one shifting element 106, so that the function of the locking is not susceptible to errors.

To release the lock, the push button 148 must be moved in the actuation direction B, i.e. downwards. This causes the contact surface 154 to contact the counter-contact surface 156, which runs parallel to the shaft axis W in the unswiveled state.

When the push button 148 is pressed further in the actuation direction B, the counter-contact surface 156 slides on the contact surface 154, whereby a force is exerted on the second lever arms 116, whereby the hooks 118 are displaced radially outwards until they are completely removed from the groove 132 (cf. Fig. 3 ). As a result, the hooks 118 no longer rest against the upper projection 134 and the hub 110 can be pulled off the drive shaft 104, whereby the push button 148 slides upwards after it is released by the spiral spring 162 until the collar 150 rests against the closure element 142 (cf. Fig. 1 ).

Although an example was shown above in which levers 106 pivotable about an axis 108 were used, levers pivotable about an axis and arranged on the drive shaft can also be used.

In addition, the actuating element 146 does not necessarily have to be arranged on the hub 110 of the centrifuge rotor 102, it can also be arranged on the drive shaft.

In Fig. 7 a laboratory centrifuge 200 is shown which is equipped with the connecting structure 10 according to the invention.

It can be seen that this laboratory centrifuge 200 is designed in a conventional manner and has a housing 202 with a control panel 206 arranged on its front side 204 and a lid 208 which is provided for closing the centrifuge container 210. A fixed-angle rotor 12 is arranged in the centrifuge container 210 as a centrifuge rotor, which can be driven by the drive shaft of a centrifuge motor (neither shown).

From the above description it has become clear that the present invention provides a connecting structure 100 between centrifuge rotor 102 and drive shaft 104 of a laboratory centrifuge 200, by means of which one-hand operation is possible for which no additional tools are required. The connecting structure 100 is designed in such a way that the locking 118, 132, 134 is always ensured, whereby jamming or blocking of locking elements 118, 132, 134 cannot occur.

list of reference symbols

100

connecting construction according to the invention in a preferred embodiment

102

centrifuge rotor

104

drive shaft

106

lever, first locking elements

108

axes of the levers 106

110

hub

112

receiving space for the drive shaft

114

first lever arm

116

second lever arm

118

Hook

120

hexagon socket of the hub 110

122

external hexagon of the drive shaft 104

124

inner cone of the hub 110

126

conical section of the drive shaft 104

128

inner cylinder of the hub 110

129

Screwing of bearing block 130 to hub 110

130

bearing block

131

boom on bearing block 130 for axles 108

132

Nut

134

upper projection of the groove 132, second locking element

136

chamfer on drive shaft 104

137

Circumferential design of the groove 132 in the form of an external hexagon

138

bevels on the hooks 118

140

cylindrical cavity of the hub

142

lid-shaped closure element

143

Screwing the locking element 142 to the hub 110

144

opening

146

actuator

148

Push button, body of the actuating element 146

150

collar

152

projection

154

Section with conical inner contour, contact surface

156

counter surface of the lever 106

158

Raising the bearing block 130

160

deepening

162

spiral spring

164

Section with conical inclination of the opening 144

166

conical counter section of the actuating element 146

200

laboratory centrifuge

202

Housing

204

front of the case 202

206

control panel

208

Lid

210

centrifuge container

B

Actuation direction of the actuating element 146

M

center of mass of the levers 106

W'

shaft axis

Claims (11)

1. Connection construction (100) with a centrifuge rotor (102) and a drive shaft (104) of a centrifuge motor extending along a shaft axis (W), wherein a first locking element (106) is arranged on one of the elements out of the centrifuge rotor (102) and the drive shaft (104) and a second locking element (134) is arranged on the other of the elements out of the centrifuge rotor (102) and the drive shaft (104), wherein the first locking element (106) is in engagement with the second locking element (134) in the locked state of the connection and is not in engagement therewith in the unlocked state, wherein there is an actuation means (146) on one of the elements out of the centrifuge rotor (102) and the drive shaft (104), the actuation of which causes the first locking element (106) to come out of engagement with the second locking element (134), whereby the centrifuge rotor (102) is removable from the drive shaft (104), characterised in that the first locking element is a lever (106) of which the lever arm (114) is movable in a plane parallel to the shaft axis (W), and in that the actuation means (146) comprises a contact surface (154) for a mating contact surface (156) of the first locking element (106), wherein the contact surface (154) has an inclined course in the actuation direction (B) of the actuation means (146), at least in the locked state of the connection construction (100), such that actuation of the actuation means (146) causes the first locking element (106) to pivot, wherein the contact surface (154) extends so as to be inclined in an axial direction of the shaft axis (W).
2. Connection construction (100) according to claim 1, characterised in that the lever arm (114) is movable in a plane that includes the shaft axis (W).
3. Connection construction (100) according to claim 2, characterised in that the lever (106) is pivotally mounted about a pin (108).
4. Connection construction (100) according to any of the preceding claims, characterised in that the first connecting means (106) has at least one chamfer (138), which serves as a locking aid, wherein the chamfer (138) is preferably parallel to the longitudinal extension of the lever (106).
5. Connection construction according to any of the preceding claims, characterised in that the first locking element is preloaded in the direction of engagement with the second locking element.
6. Connection construction (100) according to any of the preceding claims, characterised in that there are at least two first locking elements (106), preferably three first locking elements (106).
7. Connection construction (100) according to any of the preceding claims, characterised in that the first locking element (106) is arranged on the centrifuge rotor (102).
8. Connection construction (100) according to any of the preceding claims, characterised in that the second locking element (134) is a projection (134) of the drive shaft (104), behind which the first locking element (106) engages in the locked state.
9. Connection construction (100) according to any of the preceding claims, characterised in that the actuation means (146) is formed as a push button (148) that is configured to be preloaded (162) counter to the actuation direction (B).
10. Connection construction (100) according to any of the preceding claims, characterised in that the actuation means (146) is on the centrifuge rotor (102).
11. Connection construction according to any of the preceding claims, characterised in that the connection construction provides a snap-in connection, wherein the locking takes place as part of a clip connection, which is configured to be releasable.

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