Joint locking mechanism for holding-arms of medical surgical devices

Abstract

The invention relates to a joint locking mechanism (1) for holding-arms of medical surgical devices comprising a gear (3) arranged on a pivot axis (2) of a joint and a spring-loaded roller (4, 5) which is in direct operative connection with the gear (3). A joint locking mechanism (1) for holding-arms of medical surgical devices, which ensures reduced wear on the roller (4, 5) and / or gear (3) while maintaining the same positioning capability of the joint, is characterised according to the invention by two spring-loaded rollers (4, 5), which are in direct operative connection with at least one gear (3), such that in each latching position of the joint, at least one roller (4 or 5) always engages in a latching manner in a tooth gap (12) between two adjacent teeth (13) of at least one gear (3).

Description

[0001] Articulated locking device for holding arms of medical surgical equipment

[0002] The invention relates to an articulated locking device for holding arms of medical operating devices with a gear arranged on a pivot axis of a joint and a spring-loaded roller in direct operative connection with the gear.

[0003] Support arms for medical surgical equipment, such as surgical robots or support stands, are known in practice in a wide variety of designs. To enable the support arms to be positioned in the required position in space, the joints of the support arms are equipped with joint locks, which allow the support arms to be fixed in the currently required position.

[0004] A joint lock with a gear arranged on a pivot axis of a joint and a spring-loaded roller in direct operative connection with the gear is known from the prior art. To lock the joint, the spring-loaded roller is pressed into a tooth gap between two teeth of the gear, thus preventing further pivoting of the holding arm. In order to be able to pivot the joint designed in this way in the smallest possible locking steps, the gear arranged on the pivot axis of the joint has as many teeth as possible and therefore also as many tooth gaps serving for locking purposes. The more teeth a gear has, the narrower and more pointed the tooth tips of the respective teeth are.

[0005] The more tooth gaps there are on a gear, the narrower the respective tooth gap and the smaller the radius of the roller used for locking, which is to be accommodated in the tooth gap.

[0006] A joint lock designed in this way has certainly proven itself in practice, but it has been found that not only the small rollers are subject to high wear due to the contact pressure generated by the spring load and the rolling over the pointed teeth or tooth tips, but also the teeth or tooth tips of the gear, which can lead to a reduced locking performance of the joint.

[0007] Based on this, the invention is based on the object of designing a joint lock for holding arms of medical operating devices in such a way that it ensures reduced wear of the roller and / or gear while maintaining the same positioning option of the joint.

[0008] The solution to this problem is characterized according to the invention by two spring-loaded rollers which are in direct operative connection with at least one gearwheel in such a way that in each locking position of the joint at least one roller always engages in a tooth gap between two adjacent teeth of at least one gearwheel.

[0009] By using two spring-loaded rollers, it is possible to reduce the number of teeth on at least one gear while maintaining the same number of locking positions. This in turn also allows for an increase in the radius of the two rollers. Increasing the roller diameter and distributing the contact pressure between two rollers significantly reduces wear on the rollers as well as on the teeth or tooth tips of at least one gear.

[0010] A first embodiment of the invention proposes that the two rollers be mounted for tilting movement at the end of a pivot lever spring-loaded by at least one spring element and are directly operatively connected to a single gearwheel, wherein the tilting plane in which the two rollers can be tilted relative to the gearwheel is arranged parallel to the gearwheel. The tilting movement of the two rollers facilitates the transition from one tooth gap to the next when pivoting the holding arm into a new position.

[0011] To implement the tiltable mounting of the two rollers, the invention proposes that the two rollers be arranged at their ends on a two-armed rocker arm, wherein the rocker arm is pivotably mounted on the end of the pivot lever remote from the at least one spring element. By arranging the two rollers on a rocker arm, which in turn is pivotably mounted on the spring-loaded pivot lever, the contact pressure of the at least one spring element is applied evenly to both rollers.

[0012] Furthermore, the invention proposes that in each locking position one roller is arranged in a tooth gap of the gearwheel while the other roller is arranged on a tooth tip of the same gearwheel. Through this arrangement of the two rollers to one another and relative to the tooth gaps and tooth tips of the gearwheel, it is possible that with each rotation of the gearwheel by only half a tooth gap distance, one roller, namely the one previously arranged on the tooth tip, engages in a tooth gap in a locking manner, while the roller previously arranged in the tooth gap is now arranged on the nearest tooth tip. This adjustment of the gearwheel in half steps, measured by the tooth gap distance of the gearwheel, enables the joint to have the same number of locking positions as when using a gearwheel with twice as many teeth.

[0013] According to a second embodiment of the invention, it is proposed that the two rollers are mounted in a tiltable manner at the end of a pivoting lever spring-loaded by at least one spring element, and that each of the two rollers is in direct operative connection with a separate gear, wherein the two rollers are tiltable in two parallel tilting planes relative to the two gears, both of which are arranged parallel to the two gears. In this embodiment, the contact pressure exerted by the at least one spring element on the pivoting lever and thus on the two rollers is transmitted evenly to the gears assigned to the respective rollers in order to achieve effective locking of the joint.

[0014] Furthermore, the invention proposes that when two gearwheels are used, the two identically designed gearwheels are arranged parallel to each other on the pivot axis of the joint in such a way that each tooth of one gearwheel is arranged centrally to a tooth gap of the other gearwheel.

[0015] To implement the tiltable mounting of the two rollers, the invention proposes that the two rollers be arranged at their ends on a two-armed rocker arm, wherein the rocker arm is pivotably mounted on the end of the pivot lever remote from the at least one spring element. By arranging the two rollers on a rocker arm, which in turn is pivotably mounted on the spring-loaded pivot lever, the contact pressure of the at least one spring element is applied evenly to both rollers.

[0016] This arrangement of the two gears to each other also allows locking in half steps; measured by the tooth gap distance of the individual gears, this allows the same number of locking positions of the joint as when using a gear with twice as many teeth.

[0017] In this inventive arrangement of the two gears relative to each other, in each locking position one roller is arranged in a tooth gap of one gear, while the other roller is arranged on a tooth head of the other gear.

[0018] To prevent play between the roller arranged in a tooth gap and the respective tooth gap, which could impair the precise positioning of the holding arm in the locking positions of the articulated locking mechanism, the invention proposes that each roller, when arranged in a tooth gap, only bears against the tooth flanks on both sides of the respective tooth gap at specific points. The only specific contact of the rollers with the tooth flanks guarantees precise and play-free positioning of the respective roller in the corresponding tooth gap.

[0019] The contact areas of the tooth flanks, on which a roller rests at specific points on the tooth flank, are designed according to the invention as straight lines in order to ensure a defined introduction of force from the contact pressure of the roller into the tooth flanks that rest tangentially on the roller for secure locking of the joint. Finally, the invention proposes that the tooth base of each tooth gap between two adjacent teeth is designed in the shape of a pitch circle such that the radius of each tooth base of the at least one gear wheel is smaller than the radius of each roller. By forming the two different radii, it is simple in terms of production technology to achieve only specific points in contact between the rollers and the tooth flanks.

[0020] Further features and advantages of the invention will become apparent from the accompanying drawings, in which two embodiments of an articulated locking device according to the invention for holding arms of medical surgical devices are shown only by way of example, without limiting the invention to these embodiments. The drawings show:

[0021] Fig. 1 is a schematic front view of a first embodiment of an articulated locking device for holding arms according to the invention;

[0022] Fig. 2 is a schematic front view of a second embodiment of an articulated locking device according to the invention for holding arms and

[0023] Fig. 3 is an enlarged schematic representation of detail III according to Fig. 1.

[0024] The figure Fig. 1 shows an articulated locking device 1 for holding arms of medical surgical devices, such as surgical robots or holding stands.

[0025] The support arm, which can be pivoted about a pivot axis 2, is not shown in the illustrations, since the structure and design of the articulated lock 1 are independent of the design of the support arm. In order to be able to position the support arms in the required pivoting position in space, the joints of the support arms are equipped with at least one articulated lock 1, via which the respective support arm can be fixed in the currently required position.

[0026] The joint lock 1 shown in Fig. 1 essentially consists of a gear 3 arranged on the pivot axis 2 of a joint and two spring-loaded rollers 4 and 5 that are in direct operative connection with the gear 3. For this purpose, the two rollers 4, 5 are mounted in a tiltable manner at the end of a pivot lever 7 that is spring-loaded via at least one spring element 6.

[0027] The pivot lever 7, in turn, is mounted on a joint housing 9 so as to be pivotable about a pivot axis 8. The at least one spring element 6 is mounted on the one hand on the pivot lever 7 and on the other hand on an abutment 10 on the joint housing 9.

[0028] As can also be seen from Fig. 1, the two rollers 4 and 5 are arranged at the ends of a two-armed rocker arm 11, the rocker arm 11 being pivotably mounted on the end of the pivot lever 7 remote from the at least one spring element 6. With this arrangement of the rollers 4 and 5 on the rocker arm 11, the tilting plane KE-1 in which the two rollers 4 and 5 can be tilted relative to the gear 3 is arranged parallel to the gear 3.

[0029] The two rollers 4 and 5 are arranged relative to the gear 3 on the rocker arm 11 in such a way that in each locking position, one roller 4 or 5 is arranged in a tooth gap 12 between two adjacent teeth 13 of the gear 3, while the other roller 5 or 4 is arranged on a tooth head 14 of a tooth 13 of the same gear 3. The joint lock 1 shown in Fig. 1 operates as follows:

[0030] When the holding arm of the medical operating device is pivoted about the pivot axis 2, the gear wheel 3 arranged on the pivot axis 2 is inevitably also rotated about the pivot axis 2 to the same extent as the holding arm.

[0031] In the locking position shown in Fig. 1, the pivot lever 7 presses the two rollers 4 and 5, which are mounted on the rocker lever 11 in a tiltable manner, downwards in the direction of the gear 3 with the spring force of the spring element 6 in such a way that the roller 4 is arranged in a tooth gap 12 between two adjacent teeth 13 of the gear 3, while the other roller 5 is arranged on a tooth head 14 of a tooth 13 of the same gear 3.

[0032] If the gear wheel 3 is now rotated clockwise in the direction of the arrow 15 via the holding arm, this causes the roller 4 arranged in the tooth gap 12 to roll up the tooth flank 16 of the adjacent tooth 13 to the tooth tip 14, while the roller 5 arranged on the tooth tip 14 rolls down the nearest tooth flank 16 into the tooth gap 12.

[0033] This arrangement of the two rollers 4 and 5 relative to one another and relative to the tooth gaps 12 and tooth tips 14 of the gearwheel 3 makes it possible for a roller 4 or 5, namely the one previously arranged on the tooth tip 14, to engage in a tooth gap 12 with a locking action for each rotation of the gearwheel 3 by only half a tooth gap distance, while the roller 4 or 5 previously arranged in the tooth gap 12 is now arranged on the nearest tooth tip 14. This adjustment of the gearwheel 3 in half steps, measured at the tooth gap distance of the gearwheel 3, enables the joint to have the same number of locking positions as when using a gearwheel with twice as many teeth but only one roller for locking in a tooth gap 12. Only the mounting of the rollers 4 and 5 on the rocker lever 11, which can be tilted relative to the pivot lever 7, enables this locking of the rollers 4 and 5 in half the tooth gap distances.

[0034] The spring-loaded pivot lever 7 ensures that the rollers 4 and 5 are always in direct operative connection with the gear 3 and that the respective roller 4 or 5 arranged in a tooth gap 12 fixes the gear 3 and thus the holding arm in the respective position.

[0035] The second embodiment of the joint lock 1 shown in Fig. 2 differs from the joint lock 1 shown in Fig. 1 and described above in that two identically designed gear wheels 3 and 17 are now arranged parallel to one another on the pivot axis 2 of the joint.

[0036] As can be seen from Fig. 2, the two gear wheels 3 and 17 are arranged in such a way that each tooth 13 of one gear wheel 3 or 17 is arranged centrally to a tooth gap 12 of the other gear wheel 17 or 3.

[0037] In this embodiment of the articulated locking device 1, the two rollers 4 and 5 are mounted in a tiltable manner at the end of the pivot lever 7, which is spring-loaded by at least one spring element 6, in such a way that each of the two rollers 4 and 5 is in direct operative connection with a separate gear wheel 3, 17.

[0038] The spring-loaded pivot lever 7 is in turn mounted on the joint housing 9 so as to be pivotable about a pivot axis 8, wherein the at least one spring element 6 is mounted on the one hand on the pivot lever 7 and on the other hand on a support 10 on the joint housing 9. As can also be seen from Fig. 2, the two rollers

[0039] 4 and 5 are arranged at the end of a two-armed rocker lever 11, wherein the rocker lever 11 is pivotably mounted on the end of the pivot lever 7 remote from at least one spring element 6.

[0040] With this arrangement of the rollers 4 and 5 on the rocker arm 11, the two rollers 4 and 5 can be tilted in two parallel tilting planes KE-2 relative to the two gear wheels 3 and 17, wherein the two tilting planes KE-2 are arranged parallel to the two gear wheels 3 and 17.

[0041] The two rollers 4 and 5 are arranged relative to the gears 3 and 17 on the rocker arm 11 in such a way that in each locking position one roller 4 or 5 is arranged in a tooth gap 12 between two adjacent teeth 13 of one gear 3 or 17, while the other roller 5 or 4 is arranged on a tooth head 14 of a tooth 13 of the other gear 17 or 3.

[0042] The joint lock 1 shown in Fig. 2 works as follows:

[0043] When the holding arm of the medical operating device is pivoted about the pivot axis 2, the two gear wheels 3 and 17 arranged on the pivot axis 2 are inevitably rotated about the pivot axis 2 to the same extent as the holding arm.

[0044] In the locking position shown in Fig. 2, the pivot lever 7 presses the two rollers 4 and 5 mounted on the rocker lever 11 with the spring force of the spring element 6.

[0045] 5 downwards in the direction of the two gear wheels 3 and 17 in such a way that the roller 4 is arranged in a tooth gap 12 between two adjacent teeth 13 of the gear wheel 3 , while the other roller 5 is arranged on a tooth head 14 of a tooth 13 of the other gear wheel 17 .

[0046] If the two gear wheels 3 and 17 are now rotated clockwise in the direction of arrow 15 via the holding arm, this causes the roller 4 arranged in the tooth gap 12 of the gear wheel 3 to roll up the tooth flank 16 of the adjacent tooth 13 to the tooth tip 14, while the roller 5 arranged on the tooth tip 14 of the gear wheel 17 rolls down the nearest tooth flank 16 into the tooth gap 12.

[0047] Through this arrangement of the two rollers 4 and 5 to each other and relative to the tooth gaps 12 and tooth heads 14 of the two gears 3 and 17, it is possible that with each rotation of the gears 3 and 17 by only half a tooth gap distance, a roller 4 or 5, namely the one previously arranged on the tooth head 14 of one gear 3 or 17, engages in a tooth gap 12 in a locking manner, while the roller 4 or 5 previously arranged in the tooth gap 12 of the gear 17 or 3 is now arranged on the nearest tooth head 14.

[0048] This adjustment of the gear 3 in half steps, measured by the tooth gap spacing of the gear 3, enables the same number of locking positions of the joint as when using a gear with twice as many teeth, but only one roller for locking in a tooth gap 12. Only the mounting of the rollers 4 and 5 on the rocker lever 11, which can be tilted relative to the pivot lever 7, enables this locking of the rollers 4 and 5 at half the tooth gap spacing.

[0049] The spring-loaded pivot lever 7 ensures that the rollers 4 and 5 are always in direct operative connection with the two gear wheels 3 and 17 and that the respective roller 4 or 5 arranged in a tooth gap 12 fixes the gear wheel 3 or 17 and thus the holding arm in the respective position. The two embodiments of an articulated lock 1 shown in Figures 1 and 2 are characterized in that, due to the two rollers 4 and 5 used, which enable locking at half tooth gap intervals, the individual gear wheels 3 and 17 can be designed with relatively wide tooth gaps and the rollers 4 and 5 can also have a correspondingly large radius, so that the wear on the rollers 4 and 5 and on the tooth tips 14 of the gear wheels 3 and 17 is significantly reduced compared to the articulated locks 1 known from the prior art.

[0050] In order to avoid a play between the roller 4 or 5 arranged in a tooth gap 12 and the respective tooth gap 12, which would impair the exact positioning of the holding arm in the locking positions of the articulated lock 1, each roller 4 or 5, when arranged in a tooth gap 12 of a gear 3 or 17, only rests at points on the tooth flanks 16 on both sides of the respective tooth gap 12, as shown in Fig. 3.

[0051] The only point-like contact of the rollers 4 or 5 on the tooth flanks 16 guarantees an exact and play-free positioning of the respective roller 4 or 5 in the corresponding tooth gap 12 .

[0052] The contact areas of the tooth flanks 16, on which a roller 4 or 5 rests at specific points on the respective tooth flanks 16, are advantageously designed as straight lines in order to ensure a defined introduction of force from the contact pressure of the roller 4 or 5 into the tooth flanks 16 lying tangentially on the roller 4 or 5 for secure locking of the joint. As can also be seen from Fig. 3, the tooth base 18 of each tooth gap 12 between two adjacent teeth 13 is designed in the shape of a partial circle such that the radius of each tooth base 18 of the gear wheels 3 and 17 is smaller than the radius of each roller 4 or 5. By forming the two different radii, it is simple in terms of production technology to achieve only specific contact of the rollers 4 or 5 on the tooth flanks 16.

[0053] List of reference symbols

[0054] 1 joint lock

[0055] 2 swivel axis

[0056] 3 gear

[0057] 4 roll

[0058] 5 roll

[0059] 6 spring element

[0060] 7 swivel levers

[0061] 8 swivel axis

[0062] 9 Joint housing

[0063] 10 abutments

[0064] 11 rocker lever

[0065] 12 tooth gap

[0066] 13 tooth

[0067] 14 Tooth head

[0068] 15 Arrow (clockwise)

[0069] 16 tooth flank

[0070] 17 gear

[0071] 18 Tooth base

[0072] KE-1 tilting plane

[0073] KE-2 tilting plane

Claims

Patent claims 1. Joint lock (1) for holding arms of medical operating devices with a gear (3) arranged on a pivot axis (2) of a joint and a spring-loaded roller (4, 5) in direct operative connection with the gear (3), characterized by two spring-loaded rollers (4, 5) which are in direct operative connection with at least one gear (3) in such a way that in each locking position of the joint at least one roller (4 or 5) always engages in a tooth gap (12) between two adjacent teeth (13) of at least one gear (3).

2. Articulated lock (1) according to claim 1, characterized in that the two rollers (4, 5) are mounted in a tiltable manner at the end of a pivot lever (7) spring-loaded via at least one spring element (6) and are in direct operative connection with a single gear (3), wherein the tilting plane (KE-1) in which the two rollers (4, 5) can be tilted relative to the gear (3) is arranged parallel to the gear (3).

3. Articulated lock (1) according to claim 2, characterized in that the two rollers (4, 5) are arranged at the end of a two-armed rocker lever (11), wherein the rocker lever (11) is pivotably mounted on the end of the pivot lever (7) remote from the at least one spring element (6).

4. Joint lock (1) according to claim 2 or 3, characterized in that in each locking position one roller (4 or 5) is arranged in a tooth gap (12) of the gear (3), while the other roller (5 or 4) is arranged on a tooth head (14) of the same gear (3). Joint lock (1) according to claim 1, characterized in that the two rollers (4, 5) are mounted for tilting movement at the end of a pivot lever (7) spring-loaded via at least one spring element (6), and each of the two rollers (4, 5) is in direct operative connection with a separate gear (3, 17), wherein the two rollers (4, 5) are tiltable in two parallel tilting planes (KE-2) relative to the two gears (3, 17), both of which are arranged parallel to the two gears (3, 17). Joint lock (1) according to claim 5, characterized in that the two identically designed gears (3, 17) are arranged parallel to one another on the pivot axis (2) of the joint such that each tooth (13) of one gear (3 or 17) is arranged centrally with respect to a tooth gap (12) of the other gear (17 or 3).Articulated lock (1) according to claim 5 or 6, characterized in that the two rollers (4, 5) are arranged at the ends on a two-armed rocker arm (11), the rocker arm (11) being pivotably mounted on the end of the pivot lever (7) remote from the at least one spring element (6). Articulated lock (1) according to claim one of claims 5 to 7, characterized in that in each detent position one roller (4 or 5) is arranged in a tooth gap (12) of one gear (3 or 17), while the other roller (5 or 4) is arranged on a tooth head (14) of the other gear (17 or 3). Articulated lock (1) according to one of claims 1 to 8, characterized in that each roller (4, 5), when arranged in a tooth gap (12), only contacts the... both sides of the tooth flanks (16) of the respective tooth gap (12). Articulated lock (1) according to claim 9, characterized in that the contact areas of the tooth flanks (16), at which a roller (4 or 5) rests at points on the two-sided tooth flanks (16) of the respective tooth gap (12), are designed as straight lines. Articulated lock (1) according to one of claims 1 to 10, characterized in that the tooth base (18) of each tooth gap (12) between two adjacently arranged teeth (13) is designed in the shape of a part circle such that the radius of each tooth base (18) of the at least one gear (3 or 17) is smaller than the radius of each roller (4, 5).

Images