NL2013982B1

NL2013982B1 - Grasper.

Info

Publication number: NL2013982B1
Application number: NL2013982A
Authority: NL
Inventors: Edward Aguirre Milton Jr; Tim Horeman Ir
Original assignee: Univ Delft Tech
Priority date: 2014-12-15
Filing date: 2014-12-15
Publication date: 2016-10-11

Abstract

Grasper (1) comprising at least two movable parts (4, 5) embodying a jaw, wherein each of the movable parts (4 resp. 5) is mounted on at least one support (6, 6' resp. 7, 7'), wherein a relative position of the movable parts ( 4' 5) with respect to each other is variable by changing the relative position of the supports ( 6, 6' ; 7, 7' ) with respect to each other, wherein the supports ( 6, 6' ; 7, 7' ) of the movable parts ( 4, 5) comprise flexural members, wherein the flexural members of the supports (6, 6'; 7, 7') are provided with stiffening elements and/or thickenings (9) to provide for locally increased stiffness and rigidity of the flexural members in comparison with the remainder of said flexural members.

Description

Grasper

The invention relates to a grasper comprising at least two movable parts embodying a jaw, wherein each of the movable parts is mounted on at least one support, wherein a relative position of the movable parts with respect to each other is variable by changing the relative position of the supports with respect to each other. A grasper wherein each of the movable parts is mounted on two supports and wherein said supports comprise bendable members appears to be disclosed in figure 6 of W003/026519, although this is far from certain considering the obscure discussion of this figure on page 6 of this citation's description. Considering that figure 6 of W003/026519 partly bears resemblance with the figures that are attached hereto to elucidate the invention, it is assumed that the features mentioned in the previous paragraph are known from the prior art.

The applicant's not yet published Dutch application NL 2013593 describes in accordance with the preamble of the main claim a grasper comprising at least two movable parts embodying a jaw, wherein each of the movable parts is mounted on at least one support, wherein a relative position of the movable parts with respect to each other is variable by changing the relative position of the supports with respect to each other, wherein the supports of the movable parts comprise flexural members. The flexural members arrange that a force applied by the supports to the movable parts is limited to a value which is defined by mechanical properties of the flexural members. With this construction a user is provided with haptic feedback on the forces that are applied with the grasper, as well as visual feedback regarding these forces due to bending out of the flexural members when the applied forces exceed the said predefined value defined by the mechanical properties of the flexural members. This is particularly beneficial when the grasper is used in prosthetics, robotics or surgical applications, particularly in minimal invasive surgery.

It is found however that the usefulness of the grasper of the invention can be improved by arranging that larger forces can be applied with the grasper without sacrificing its capability to provide the user with haptic and visual feedback .

The grasper of the invention is therefore provided with one or more of the features according to the appended claims .

In a first aspect of the invention the flexural members of the supports are provided with stiffening elements and/or changes in cross-sectional area (in particular thickenings) to provide for locally increased stiffness and rigidity of the flexural members. This effectively increases the possibility to apply larger forces with the grasper whilst maintaining its capability to provide visual and haptic feedback to the user.

It is preferred that there are plural stiffening elements and/or thickenings on the flexural members of the supports that are separated from each other by intermediate, in comparison with said stiffening elements and/or thickenings relatively flexible parts of the flexural members of the supports. The degree of rigidity versus flexibility of the flexural members can thus be easily tailored to the needs of the user in a particular application.

Preferably each movable part is mounted on at least two supports each comprising flexural members upon which said stiffening elements and/or thickenings are provided. This provides benefits particularly in a further embodiment in which said stiffening elements and/or thickenings on any pair of two supports supporting a movable part have cooperating teeth or interacting elements that contact or interlock with each other upon actuation of the grasper. The cooperating teeth or interacting elements further increase the amount of force that can be applied by the grasper of the invention, whilst the required flexibility is maintained.

Suitably actuation of the grasper is executed by an outer sheath which is movable longitudinally along the two movable parts between two positions, a first position in which the two movable parts are not actuated and released from restriction imposed by the outer sheath and in which the relative position of the two movable parts is determined by the relative position of the supports, and a second actuated posi tion in which the relative position of the two movable parts is restricted and determined by the outer sheath.

In quite a different embodiment of the grasper of the invention another solution is applied which is however based on the same general principle of the invention, notably that the flexural members of the supports are provided with stiffening elements and/or thickenings to provide for locally increased stiffness and rigidity of the flexural members. In this embodiment the stiffening elements and/or thickenings are embodied as casings of and movable along the flexural members of the supports and positionable by an outer sheath in that in a first position of said sheath said casings exhibit a predefined yet variable amount of play between said casings, and a second position of said sheath wherein play between the casings is avoided or counteracted. This embodiment can be further completed with the feature that each movable part is mounted on at least two supports each comprising flexural members upon which said stiffening elements and/or thickenings are provided.

The invention will hereinafter be further elucidated with reference to the drawing of an exemplary embodiment of a grasper according to the invention that is not limiting as to the appended claims.

In the drawing: - figure 1 shows a first embodiment of the grasper of the invention with the outer sheath retracted; - figure 2 shows a second embodiment of the grasper with the outer sheath retracted; -figure 3 shows a third embodiment of the grasper of the invention with the outer sheath retracted; and -figure 4 shows the third embodiment of figure 3 wherein the outer sheath is moved forward.

Whenever in the figures the same reference numerals are applied, these numerals refer to the same parts.

Making reference to both figure 1 and figure 2 the grasper of the invention is indicated with reference 1. The grasper 1 comprises two movable parts 4, 5 defining a jaw 2. The movable part 4 is mounted in this exemplary embodiment on cooperating supports 6, 6', whereas the movable part 5 is mounted on cooperating supports 7, 1' . Instead of mounting each of the movable parts on two cooperating supports it is also possible to mount each movable part on a single support which is dedicated to the concerning movable part.

Opposite to the jaw 2 is the proximal side 3 of the grasper 1 at which side the grasper is controlled. At this proximal side 3 an outer sheath 8 is provided. For clarity purposes the outer sheath 8 is shown in a position in which the two movable parts 4, 5 of the jaw 2 are released from restriction by this outer sheath 8 so as to enable that the relative position of the movable parts 4, 5 is exclusively determined by the relative position of the supports 6, 6' and 7, 7' .

Operation of the grasper 1 with the outer sheath 8 in the retracted position is as follows. Movement of movable part 4 can be done by changing the relative position of the supports 6, 6' of movable part 4 with respect to each other. Movement of movable part 5 can be done by changing the relative position of the supports 7, 7' of movable part 5 with respect to each other.

In figure 1 and figure 2 the movable parts 4, 5 of the jaw 2 are moved concertedly by movement of the central supports 6' and 7' whilst the outer supports 6 and 7 remain stationary. Alternatively it is also possible that the movable parts 4, 5 of the jaw 2 are moved concertedly by movement of the outer supports 6 and 7 whilst the central supports 6' and 7' remain stationary.

In all situations shown in figures 1 and 2 the outer sheath 8 is kept in a first position in which the two movable parts 4, 5 are released from any restriction imposed by the outer sheath 8 so that the relative position of the two movable parts 4, 5 is determined by the relative position of the supports 6, 6'; 1, 7' only. This corresponds to fine or delicate grasping.

When the outer sheath 8 is moved forward to engage the outer supports 6, 7 of the movable parts 4, 5 of the jaw 2, movement of said movable parts 4, 5 is restricted and the opening and closing of the jaw 2 is controlled by positioning and moving the outer sheath 8 back-and-forth. This corresponds to coarse or firm grasping.

It is remarked that the supports 6, 6' and 7, 1' of the movable parts 4, 5 comprise or are embodied as flexural members. One of the advantages of arranging that the supports 6, 6' and 7, 7' of the movable parts 4, 5 comprise or are embodied as flexural members is that a force applied by the supports 6, 6' and 7, 7' to the movable parts 4, 5 is limited to a well defined pre-established value which is determined by properly selecting the mechanical properties of the flexural members. It will be clear that this only applies when the outer sheath 8 is in the retracted position, when the position of the movable parts 4, 5 is only determined by their supports 6, 6' and 7, 7' .

In both the embodiment of figure 1 and in the embodiment of figure 2 each movable part 4; 5 is mounted on at least two supports 6, 6'; 7, 7' but as mentioned above it is also possible to have a single support dedicated for each movable part.

According to the invention the flexural members of the supports 6, 6'; 7, 1' are provided with stiffening elements and/or thickenings 9 to provide for locally increased stiffness and rigidity of the flexural members in comparison with the remainder of said flexural members. Figure 1 shows that there are plural stiffening elements and/or thickenings 9 which are provided only on the flexural members of the outer supports 6, 7. The rigidity of the inner supports 6', 7' is not particularly increased. These stiffening elements and/or thickenings 9 are separated from each other by intermediate, in comparison with said stiffening elements and/or thickenings 9 relatively flexible parts 10 of the flexural members of the supports 6, 7 to maintain a defined flexibility of the supports 6, 7.

In the embodiment of figure 2 the flexural members of both the inner supports 6', 1' and the outer supports 6, 7 are provided with said stiffening elements and/or thickenings 9. Figure 2 further shows that said stiffening elements and/or thickenings 9 on any pair of two supports 6, 6'; 7, 7' supporting a movable part 4; 5 have cooperating teeth 11 (on the surface of the thickenings 9 on supports 6, 6') or interacting elements (roughenings) 12 (on the surface of the thickenings 9 on supports 7, 7') that are capable to contact or interlock with each other upon actuation of the grasper 1. Such actuation is then done by moving the outer sheath 8 forward to restrict movement of the two movable parts (4, 5) and to position the grasper in the 'coarse' or 'firm' grasping mode of operation in the manner as explained hereabove. The interlocking or contacting teeth 11 or roughenings 12 provided on the neighboring supports 6, 6' and 7, 7' then further support and increase the amount of force that can be applied with the grasper of the invention. This is not further shown in the drawing considering that the manner in which this operates is perfectly clear for the skilled person. There is therefore no need for a further elucidation with reference to the drawing without compromising the skilled person's capability to work within the scope of the invention.

Figure 3 and 4 relate to a different embodiment of the grasper 1 of the invention, which has the feature that the stiffening elements and/or thickenings are embodied as casings 9 of and movable along the flexural members of the supports 6, 7. These casings 9 are positionable by an outer sheath 8 which can assume two separate positions. Figure 3 depicts a first position in which said sheath 8 is retracted and consequently said casings 9 exhibit a predefined yet variable amount of play 13 between said casings 9. This results in a relatively limited amount of force that can be applied with the movable parts 4, 5 that constitute the jaw of the grasper. In a second and forwardly moved position of said sheath 8 as depicted in figure 4, play between the casings 9 is avoided or counteracted, and consequently flexibility of the flexural members of the supports 6, 7 is restricted. In this position relatively higher forces can be applied with the movable parts 4, 5 constituting the jaw of the grasper.

Although the invention has been discussed in the foregoing with reference to exemplary embodiments of the grasper of the invention, the invention is not restricted to this particular embodiment which can be varied in many ways without departing from the gist of the invention. The discussed exemplary embodiments shall therefore not be used to construe the appended claims strictly in accordance therewith. On the contrary the embodiments are merely intended to explain the wording of the appended claims without intent to limit the claims to this exemplary embodiment. The scope of protection of the invention shall therefore be construed in accordance with the appended claims only, wherein a possible ambiguity in the wording of the claims shall be resolved using these exemplary embodiments.

Claims

1. Grasper (1) comprising at least two movable parts (4, 5) embodying a jaw, wherein each of the movable parts (4 resp. 5) is mounted on at least one support (6, 6' resp. 7, T), wherein a relative position of the movable parts (4, 5) with respect to each other is variable by changing the relative position of the supports (6, 6'; 7, 7') with respect to each other, wherein the supports (6, 6'; 7, 7') of the movable parts (4, 5) comprise flexural members, characterized in that the flexural members of the supports (6, 6'; 7, 7') are provided with stiffening elements and/or changes in cross-sectional area such as thickenings (9) to provide for locally increased stiffness and rigidity of the flexural members.

2. Grasper (1) according to claim 1, characterized in that there are plural stiffening elements and/or thickenings (9) on the flexural members of the supports (6, 6'; 7, 7') that are separated from each other by intermediate, in comparison with said stiffening elements and/or thickenings relatively flexible parts (10) of the flexural members of the supports (6 , 6 ' ; 7 , 7' ) ·

3. Grasper (1) according to claim 1 or 2, characterized in that each movable part (4; 5) is mounted on at least two supports (6, 6'; 7, 7') each comprising flexural members upon which said stiffening elements and/or thickenings (9) are provided.

4. Grasper (1) according to claim 3, characterized in that said stiffening elements and/or thickenings (9) on any pair of two supports (6, 6'; 7, 7') supporting a movable part (4; 5) have cooperating teeth (11) or interacting elements such as roughenings (12) that contact or interlock with each other upon actuation of the grasper.

5. Grasper (1) according to claim 3 or 4, characterized in that actuation is executed by an outer sheath (8) which is movable longitudinally along the two movable parts (4, 5) between two positions, a first position in which the two movable parts (4, 5) are not actuated and released from restriction imposed by the outer sheath (8) and in which the relative position of the two movable parts (4, 5) is deter mined by the relative position of the supports (6, 6'; 7, 7'), and a second actuated position in which the relative position of the two movable parts (4, 5) is restricted and determined by the outer sheath (8).

6.

Grasper (1) according to any one of claims 1, 3 or 5, characterized in that the stiffening elements and/or thickenings are embodied as casings (9) of and movable along the flexural members of the supports (6, 6'; 7, 7') and positiona-ble by an outer sheath (8) in that in a first position of said sheath (8) said casings (9) exhibit a predefined yet variable amount of play (13) between said casings (9), and a second position of said sheath (8) wherein play between the casings (9) is avoided or counteracted.