Joint stop for retaining arm of medical surgical device

Abstract

The invention relates to a joint stop (1) for a holding arm of a medical surgical device, comprising a gearwheel (3) arranged on a pivot axis (2) of the joint and a spring-loaded roller (4, 5) directly operatively connected to the gearwheel (3). The invention relates to a joint stop (1) for a retaining arm of a medical surgical device, which ensures reduced wear of rollers (4, 5) and / or gear wheels (3) while maintaining a constant positioning capacity of the joint, characterized in that according to the invention two spring-loaded rollers (4, 5) are directly operatively connected to at least one gear wheel (3), the joint is designed such that in each locking position of the joint, at least one roller (4 or 5) always engages in a locking manner in a tooth space (12) between two adjacent teeth (13) of the at least one gear (3).

Description

Technical Field

[0001] The invention relates to a joint stop for a holding arm of a medical surgical device, comprising a gear arranged on a pivot axis of the joint and a spring-loaded roller directly operatively connected to the gear. Background Art

[0002] In practice, holding arms or holding tripods for medical surgical devices, such as surgical robots, are known in various embodiments. In order to be able to position the holding arm in the respective desired position for pivoting in space, the joints of the holding arm are provided with joint stops, via which the holding arm can be fixed in the currently desired position.

[0003] A joint stop is known from the prior art, which has a gear arranged on the pivot axis of the joint and a spring-loaded roller which is directly operatively connected to the gear. To stop the joint, the spring-loaded roller is pressed into the tooth gap between two teeth of the gear and thus prevents further pivoting of the holding arm. In order to enable a joint designed in this way to be pivotable with as small a locking step as possible, the gear arranged on the pivot axis of the joint has as many teeth as possible and thus also has a plurality of tooth gaps for locking. The more teeth a gear has, the narrower and more pointed the tooth tops of the respective teeth are.

[0004] The more tooth gaps are formed on the gear, the narrower the corresponding tooth gaps are, and the smaller the radius of the rollers that are to be received in the tooth gaps for locking purposes is.

[0005] A joint stop designed in this way has proven its worth in practice, but it has been found that not only the small rollers but also the teeth or tooth tops of the gears are subject to a high degree of wear due to the pressing forces generated by the spring loading and the rolling on the pointed teeth or tooth tops, which leads to a reduction in the stopping properties of the joint. Summary of the invention

[0006] The object of the present invention is therefore to design a joint stop for a holding arm of a medical surgical device in such a way that it ensures reduced wear of the rollers and / or gears while maintaining the positioning capability of the joint.

[0007] According to the invention, the solution to this object is characterized by two spring-loaded rollers which are directly operatively connected to at least one gear so that in each locking position of the joint at least one roller is always engaged in a locking manner in a tooth gap between two adjacent teeth of at least one gear.

[0008] By using two spring-loaded rollers, it is possible to reduce the number of teeth of the at least one gear while maintaining the number of locking positions, which in turn enables an increase in the radius of the two rollers. The increase in roller diameter and the sharing of the pressing force applied to the two rollers significantly reduce the wear of the rollers and the teeth or tooth tips of the at least one gear.

[0009] A first embodiment of the invention provides that two rollers are supported in a tiltable manner at the end of a pivot lever which is spring-loaded via at least one spring element and are directly operatively connected to a single gear, wherein an inclination plane is arranged parallel to the gear, in which the two rollers can be tilted relative to the gear. The tiltable mounting of the two rollers facilitates the changeover from one tooth gap to the next when the holding arm is pivoted into a new position.

[0010] In order to realize the tiltable mounting of the two rollers, it is proposed according to the invention that the two rollers are arranged at the end of a double-armed rocker, wherein the rocker is pivotably mounted at the end of the pivot lever remote from the at least one spring element. Due to the arrangement of the two rollers on the rocker, which for its part is pivotably mounted on the spring-loaded pivot lever, the contact force of the at least one spring element is applied uniformly to the two rollers.

[0011] The invention further proposes that in each locking position, one roller is arranged in the tooth gap of the gear and the other roller is arranged on the tooth top of the same gear. This arrangement of the two rollers relative to one another and to the tooth gaps and tooth tops of the gear makes it possible that, with each rotation of the gear by only half the tooth gap distance, the roller, i.e. the roller previously arranged on the tooth top, engages in a locking manner in the tooth gap, while the roller previously arranged in the tooth gap is now arranged on the nearest tooth top. Adjusting the gear in half steps (determined by measuring the tooth gap distance of the gear) allows the same number of locking positions of the joint to be achieved as when using a gear with twice as many teeth.

[0012] According to a second embodiment of the invention, two rollers are supported in a tiltable manner at the end of a pivot rod spring-loaded via at least one spring element, and each of the two rollers is directly operatively connected to a separate gear, wherein the two rollers can be tilted relative to the two gears in two parallel tilting planes, which are arranged parallel to the two gears. In this design, the contact force exerted on the pivot rod and thus on the two rollers via at least one spring element is uniformly transmitted to the gears associated with the respective rollers, so as to achieve effective locking of the joint.

[0013] The invention further proposes that when two gears are used, two gears of identical design are arranged parallel to one another on the pivot axis of the joint in such a way that each tooth of one gear is arranged centrally relative to a tooth gap of the other gear.

[0014] In order to realize the tiltable mounting of the two rollers, it is proposed according to the invention that the two rollers are arranged at the end of a double-armed rocker, wherein the rocker is pivotably mounted at the end of the pivot lever remote from the at least one spring element. Due to the arrangement of the two rollers on the rocker, which for its part is pivotably mounted on the spring-loaded pivot lever, the contact force of the at least one spring element is applied uniformly to the two rollers.

[0015] This arrangement of the two gears relative to one another also allows locking of the gears in half steps (determined by measuring the tooth gap distance of the individual gears), which enables the same number of locking positions of the joint as when using gears with twice as many teeth.

[0016] In this arrangement according to the invention of the two gear wheels relative to one another, in each locked position one roller is arranged in a tooth gap of one gear wheel and the other roller is arranged on a tooth crest of the other gear wheel.

[0017] In order to avoid a gap between the rollers arranged in the tooth gap and the corresponding tooth gap in the locked position of the joint stop, which would impair the precise positioning of the holding arm, it is proposed according to the invention that each roller, when arranged in the tooth gap, only bears in spots against the tooth flanks on both sides of the corresponding tooth gap. The only spot-like bearing of the rollers against the tooth flanks ensures precise and play-free positioning of the corresponding roller in the associated tooth gap.

[0018] According to the invention, the tooth flank contact area is designed as a straight line where the roller contacts the tooth flank in a punctiform manner in order to ensure a defined force introduction of the roller's contact force into the tooth flank contacting tangentially to the roller for reliable locking of the joint.

[0019] The invention finally proposes that the tooth root of each tooth groove between two teeth arranged side by side is configured as a part of a circle. The radius of each tooth root of at least one gear is smaller than the radius of each roller. By forming two different radii, it is easier to achieve only point-like contact of the rollers on the tooth flanks in terms of production technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Further features and advantages of the invention are apparent from the associated illustrations, in which two embodiments of a joint stop for a holding arm of a medical surgical device according to the invention are shown only by way of example, without restricting the invention to these embodiments. In the drawings:

[0021] Figure 1 A schematic front view showing a first embodiment of a joint stop for a holding arm according to the present invention;

[0022] Figure 2 A schematic front view showing a second embodiment of a joint stop for a holding arm according to the present invention; and

[0023] Figure 3 Shown according to Figure 1 A magnified schematic diagram of the detail III. DETAILED DESCRIPTION

[0024] Attached photos Figure 1 A joint stop 1 is shown for a medical surgical device, for example a holding arm or a holding tripod of a surgical robot.

[0025] The holding arm, which is pivotable about the pivot axis 2 , is not shown in the figures, since the structural and constructive design of the joint stop 1 is independent of the design of the holding arm.

[0026] In order to be able to position the holding arm in the respectively required position for pivoting in space, the joint of the holding arm is provided with at least one joint stop 1 , via which the respective holding arm can be fixed in the currently required position.

[0027] exist Figure 1 The joint stop 1 shown in the figure is essentially composed of a gear 3 arranged on the pivot axis 2 of the joint and two spring-loaded rollers 4 and 5 which are directly operatively connected to the gear 3. For this purpose, the two rollers 4, 5 are supported in a tiltable manner at the end of a pivot lever 7 which is spring-loaded via at least one spring element 6.

[0028] The pivot lever 7 for its part is supported on the joint housing 9 so as to be pivotable about a pivot axis 8. At least one spring element 6 is supported on the pivot lever 7 on one side and on a bearing 10 on the joint housing 9 on the other side.

[0029] If further from Figure 1 It can be seen that the two rollers 4 and 5 are arranged at the end of a double-arm rocker 11, wherein the rocker 11 is pivotably supported at 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 at the rocker 11, an inclined plane KE-1 is arranged parallel to the gear 3, in which the two rollers 4 and 5 can be tilted relative to the gear 3.

[0030] The two rollers 4 and 5 are arranged relative to the gear 3 on the rocker 11 so that in each locking position one roller 4 or 5 is arranged in the tooth gap 12 between two adjacent teeth 13 of the gear 3, while the other roller 5 or 4 is arranged on the tooth top 14 of the tooth 13 of the same gear 3.

[0031] Figure 1 The joint stop 1 shown works as follows:

[0032] When the holding arm of the medical surgical device is pivoted about the pivot axis 2 , the gear 3 arranged on the pivot axis 2 must rotate about the pivot axis 2 to the same extent as the holding arm.

[0033] exist Figure 1 In the locked position shown, the pivot lever 7 uses the elastic force of the spring element 6 to press the two tiltable rollers 4 and 5 supported on the rocker arm 11 downward in the direction of the gear 3, so that the roller 4 is arranged in the tooth groove 12 between two adjacent teeth 13 of the gear 3, and the other roller 5 is arranged on the tooth top 14 of the tooth 13 of the same gear 3.

[0034] If the gear 3 is now rotated clockwise in the direction of the arrow 15 via the retaining arm, this causes the roller 4 arranged in the tooth gap 12 to roll upward on 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 downward on the nearest tooth flank 16 into the tooth gap 12.

[0035] This arrangement of the two rollers 4 and 5 relative to one another and to the tooth gaps 12 and tooth crests 14 of the gear 3 makes it possible that, with each rotation of the gear 3 by only half the tooth gap distance, the roller 4 or 5, i.e. the roller 4 or 5 previously arranged on the tooth crest 14, engages in a locking manner in the tooth gap 12, while the roller 4 or 5 previously arranged in the tooth gap 12 is now arranged on the nearest tooth crest 14. Adjusting the gear 3 by half steps (determined by measuring the tooth gap distance 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 is used for locking in the tooth gap 12. Locking the rollers 4 and 5 by half the tooth gap distance is only possible if the rollers 4 and 5 are supported on a rocker 11 that can be tilted relative to the pivot lever 7.

[0036] The spring-loaded pivot lever 7 ensures that the rollers 4 and 5 are always in direct operative connection with the gear wheel 3 , and the respective roller 4 or 5 arranged in the tooth gap 12 fixes the gear wheel 3 and thus the holding arm in the respective position.

[0037] Joint stop 1 Figure 2 The second embodiment shown is Figure 1The joint stop 1 shown and described previously differs in that now two gear wheels 3 and 17 of identical design are arranged parallel to one another on the pivot axis 2 of the joint.

[0038] As from Figure 2 It can be seen in FIG. 1 that the two gear wheels 3 and 17 are arranged relative to one another in such a way that each tooth 13 of one gear wheel 3 or 17 is arranged centrally relative to a tooth gap 12 of the other gear wheel 17 or 3 .

[0039] In this embodiment of the joint stop 1 , the two rollers 4 and 5 are supported in a tiltable manner at the end of a pivot lever 7 which is spring-loaded via at least one spring element 6 , so that each of the two rollers 4 and 5 is directly operatively connected to a separate gear wheel 3 , 17 .

[0040] The spring-loaded pivot lever 7 for its part is mounted on the joint housing 9 so as to be pivotable about a pivot axis 8 , wherein at least one spring element 6 is mounted on one side on the pivot lever 7 and on the other side on a bearing 10 on the joint housing 9 .

[0041] If further from Figure 2 It can be seen in FIG. 2 that the two rollers 4 and 5 are arranged at the end sides of a double-armed rocker 11 , wherein the rocker 11 is pivotably mounted at the end of the pivot lever 7 facing away from the at least one spring element 6 .

[0042] With this arrangement of the rollers 4 and 5 at the rocker 11 , the two rollers 4 and 5 can be tilted relative to the two gears 3 and 17 in two parallel tilting planes KE- 2 , wherein the two tilting planes KE- 2 are arranged parallel to the two gears 3 and 17 .

[0043] The two rollers 4 and 5 are arranged at the rocker arm 11 relative to the gears 3 and 17 so that in each locking position one roller 4 or 5 is arranged in the tooth groove 12 between two adjacent teeth 13 of one gear 3 or 17, while the other roller 5 or 4 is arranged on the tooth top 14 of the tooth 13 of the other gear 17 or 3.

[0044] Figure 2 The joint stop 1 shown works as follows:

[0045] When the holding arm of the medical surgical device is pivoted about the pivot axis 2 , the two gear wheels 3 and 17 arranged on the pivot axis 2 must rotate about the pivot axis 2 to the same extent as the holding arm.

[0046] exist Figure 2In the locked position shown, the pivot lever 7 uses the elastic force of the spring element 6 to press the two tiltable rollers 4 and 5 supported on the rocker arm 11 downward in the direction of the two gears 3 and 17, so that the roller 4 is arranged in the tooth groove 12 between two adjacent teeth 13 of the gear 3, and the other roller 5 is arranged on the tooth top 14 of the tooth 13 of the other gear 17.

[0047] If the two gears 3 and 17 are now rotated clockwise in the direction of the arrow 15 via the retaining arm, this causes the roller 4 arranged in the tooth groove 12 of the gear 3 to roll upward on the tooth side 16 of the adjacent tooth 13 to the tooth top 14, while the roller 5 arranged on the tooth top 14 of the gear 17 rolls downward on the nearest tooth side 16 into the tooth groove 12.

[0048] This arrangement of the two rollers 4 and 5 relative to each other and to the tooth gaps 12 and tooth tops 14 of the two gears 3 and 17 makes it possible that each time the gears 3 and 17 rotate only half the tooth gap distance, the roller 4 or 5, i.e. the roller 4 or 5 previously arranged on the tooth top 14 of the gear 3 or 17, engages in a locking manner in the tooth gap 12, 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 top 14.

[0049] Adjusting the gear 3 in half steps (determined by measuring the tooth gap distance of the gear 3) allows the same number of locking positions of the joint as when using a gear with twice as many teeth, but only one roller is used for locking in the tooth gap 12. Only by supporting the rollers 4 and 5 on a rocker 11 that can be tilted relative to the pivot lever 7 can the rollers 4 and 5 be locked at half the tooth gap distance.

[0050] The spring-loaded pivot lever 7 ensures that the rollers 4 and 5 are always in direct operative connection with the two gears 3 and 17 , and the respective roller 4 or 5 arranged in the tooth gap 12 fixes the gears 3 and 17 and thus the holding arm in the respective position.

[0051] Figure 1 and Figure 2 The two embodiments for designing the joint stop part 1 are characterized in that, due to the two rollers 4 and 5 used, the two rollers can be locked at half the tooth gap distance, the respective gears 3 and 17 can be constructed with relatively wide tooth gaps, and the rollers 4 and 5 can also have a correspondingly large radius, so that the wear at the rollers 4 and 5 and at the tooth tops 14 of the gears 3 and 17 is significantly reduced compared to the joint stop part 1 known in the prior art.

[0052] In order to avoid a gap between the rollers 4 or 5 arranged in the tooth gap 12 and the respective tooth gap 12 in the locked position of the joint stop 1, which would impair the exact positioning of the holding arm, each roller 4 or 5, when arranged in the tooth gap 12 of the gear 3 or 17, only bears against the tooth flanks 16 on both sides of the respective tooth gap 12 in a dotted manner, as shown in FIG. Figure 3 shown.

[0053] The only point-like contact of the rollers 4 or 5 on the tooth flanks 16 ensures precise and play-free positioning of the respective roller 4 or 5 in the associated tooth gap 12 .

[0054] The contact area of ​​the tooth flank 16 is advantageously designed as a straight line, where the roller 4 or 5 contacts the corresponding tooth flank 16 in a point-like manner, in order to ensure a defined force introduction of the contact force of the roller 4 or 5 into the tooth flank 16 tangentially contacting the roller 4 or 5 for reliable locking of the joint.

[0055] If further from Figure 3 It can be seen that the tooth root 18 of each tooth gap 12 between two teeth 13 arranged next to each other is designed as a part of a circle, so that the radius of each tooth root 18 of the gears 3 and 17 is smaller than the radius of each roller 4 or 5. By configuring two different radii, it is easier to achieve only a point-like contact of the roller 4 or 5 on the tooth flank 16 in terms of production technology.

[0056] Description of Reference Numerals

[0057] 1 Joint stopper

[0058] 2 Pivot axis

[0059] 3 Gears

[0060] 4 rollers

[0061] 5 rollers

[0062] 6 Spring element

[0063] 7 Pivot lever

[0064] 8 Pivot axis

[0065] 9 joint housing

[0066] 10 Supports

[0067] 11 Swing Bar

[0068] 12 Tooth groove

[0069] 13 teeth

[0070] 14 tooth top

[0071] 15 Arrow (clockwise)

[0072] 16 Tooth side

[0073] 17 Gear

[0074] 18 Tooth root

[0075] KE-1 Inclined Plane

[0076] KE-2 inclined plane

Claims

1. A joint stop (1) for a holding arm of a medical surgical device, comprising a gear (3) arranged on the pivot axis (2) of the joint and spring-loaded rollers (4, 5) directly operatively connected to the gear (3), It is characterized in that Two spring-loaded rollers (4, 5) are directly operatively connected to at least one gear (3) so that in each locking position of the joint at least one roller (4 or 5) is always engaged in a locking manner in a tooth gap (12) between two adjacent teeth (13) of at least one gear (3).

2. The joint stopper (1) according to claim 1, characterized in that: The two rollers (4, 5) are supported in a tiltable manner at the end of a pivot rod (7) which is spring-loaded via at least one spring element (6) and are directly operatively connected to a single gear (3), wherein an inclined plane (KE-1) is arranged parallel to the gear (3) in which the two rollers (4, 5) can be tilted relative to the gear (3).

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

4. The joint stopper (1) according to claim 2 or 3, characterized in that: In each locking position, one roller (4 or 5) is arranged in a tooth groove (12) of the gear wheel (3), while the other roller (5 or 4) is arranged on a tooth top (14) of the same gear wheel (3).

5. The joint stopper (1) according to claim 1, characterized in that: The two rollers (4, 5) are supported in a tiltable manner at the end of a pivot rod (7) which is spring-loaded via at least one spring element (6) and each of the two rollers (4, 5) is directly operatively connected to a separate gear (3, 17), wherein the two rollers (4, 5) can be tilted relative to the two gears (3, 17) in two parallel tilting planes (KE-2), which are arranged in parallel to the two gears (3, 17).

6. The joint stopper (1) according to claim 5, characterized in that: The two identically constructed gears (3, 17) are arranged parallel to each other on the pivot axis (2) of the joint so that each tooth (13) of one gear (3 or 17) is arranged centrally relative to the tooth groove (12) of the other gear (17 or 3).

7. The joint stopper (1) according to claim 5 or 6, characterized in that: The two rollers (4, 5) are arranged at the end sides of a double-armed rocker (11), wherein the rocker (11) is pivotably mounted at the end of the pivot lever (7) remote from the at least one spring element (6).

8. The joint stopper (1) according to any one of claims 5 to 7, characterized in that: In each locking position, one roller (4 or 5) is arranged in a tooth groove (12) of one of the gears (3 or 17), while the other roller (5 or 4) is arranged on a tooth top (14) of the other gear (17 or 3).

9. The joint stopper (1) according to any one of claims 1 to 8, characterized in that: When arranged in the tooth gap (12), each roller (4, 5) rests only in spots on the tooth flanks (16) on both sides of the respective tooth gap (12).

10. The joint stopper (1) according to claim 9, characterized in that: The contact area of ​​the tooth flank (16) is designed as a straight line, in which the roller (4 or 5) contacts the tooth flank (16) on both sides of the corresponding tooth gap (12) in a point-like manner.

11. The joint stopper (1) according to any one of claims 1 to 10, characterized in that: The tooth root (18) of each tooth gap (12) between two teeth (13) arranged side by side is designed as a part of a circle, so that the radius of each tooth root (18) of the at least one gear (3 or 17) is smaller than the radius of each roller (4, 5).

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