The invention relates to an exoskeleton for supporting a user' s arm, comprising a supporting frame that supports an up-and-down movable standard on which a horizontally movable arm is mounted.

US 8,641,782 discloses such an exoskeleton which com- pensates for gravity. The known exoskeleton comprises at least five joints, wherein two joints may be driven by actuators, and the remaining joints may be driven by user force.

AT 517255 A1 discloses an arm exoskeleton for the mo- torized movement of an arm, with several modules and several drives for moving a plurality of joints of the arm.

US 9,358,173 discloses a multi-axis robotic arm having first to eight arm segments, and a high-precision control sys- tem for controlling movements of the multi-axis robotic arm.

The control system provides an active, a passive and an auxil- iary mode; receives and computes information about a patient's movements and muscle force detected by potentiometers and force sensors provided in the multi-axis robotic arm; and ac- cordingly, drives actuators to apply an aiding force or a re- sisting force to assist the patient in completing rehabilita- tion exercises.

US2010 / 0249673 discloses a system for arm therapy com- prising a first drive that can be fixedly connected to an ele- ment determining the position of a user and rotationally driv- ing, about a first axis, a part of the arm therapy system which can be connected to an upper arm module. The driven part of the arm therapy system comprises a second drive adapted to rotationally drive said upper arm module about a second axis, wherein said second axis is oriented orthogonal to the first axis. The system can provide a statically determined exoskele- ton with correct anatomical axes and misaligned technical ax- es .

W095/32842 discloses an external apparatus for attach- ment to a limb of an user and having a selected number of de- grees-of-freedom for applying torques to the limb comprising: at least one remote center drive associated with one of the selected number of degrees-of-freedom, wherein the remote cen- ter drive is adapted to generate torques on the limb remotely from the center of rotation of the selected degree of freedom.

KR 2018 0123939; CN 107 736 983; and CN 104 021 704 each disclose an exoskeleton for supporting a user' s arm, com- prising a supporting frame that supports an up-and-down mova- ble standard on which a horizontally movable arm is mounted, wherein the horizontally movable arm carries a back support and a supporting arm construction for supporting the user' s arm.

It is an object of the invention to provide an exo- skeleton which can accurately follow the natural movements of an arm of the user.

It is a further object of the invention to provide an exoskeleton which substantially balances the weight of the arm of the user.

It is still a further object of the invention to pro- vide that the exoskeleton is as much as possible self- supporting without bearing on the body of the user.

The exoskeleton of the invention has the features of one or more of the appended claims.

In a first aspect of the invention the horizontally movable arm is articulated to enable that the exoskeleton can follow all natural movements of the user.

The back support on the horizontally movable arm can in one embodiment be a shoulder plate which accurately posi- tions the supporting arm construction in relation to the users arm, and which promotes that the supporting arm construction can accurately follow the natural arm movements of the user.

To promote the capability of the exoskeleton to follow the natural movements of the user, it is preferred that the supporting arm construction is articulated and extendable so as to tailor the arm construction to the users arm dimensions.

Further it is preferred that the supporting arm con- struction has two limbs that connect to each other with a hinge, and that on opposite sides of the hinge the limb that is farthest away from the back support connects to counterbal- ancing springs that on their opposite sides connect to the up- per limb and directly or indirectly to the horizontally mova- ble arm. The counterbalancing springs are important for reduc- ing the weight of the user' s own arm that has to be compen- sated by the user himself. Preferably the limb that is farthest away from the at least one back support supports an flexible arm sleeve. With such an flexible arm sleeve a play free connection with an us- ers arm can be secured.

It is further preferred that the limb that is farthest away from the at least one back support is provided with an attached gripping flap. Such a gripping flap is very helpful when support of the users arm is required.

Advantageously the limb that is farthest away from the back support is provided with a brace that extends above the flexible arm sleeve. The brace secures the dimensional fit of the flexible arm sleeve, and in particular the construction of the lower limb of the arm construction.

The up-and-down movability of the standard can be re- alized in different ways. In one embodiment the up-and-down movable standard is supported through a parallelogram mecha- nism by the supporting frame.

It is then preferred that the parallelogram mechanism has guide wheels that guide a tension wire so as to provide a weight compensating upward force to the parallelogram mecha- nism .

Suitably the tension wire has two extremities, and connects on a first extremity of the two extremities to a spring mounted on the frame.

It is preferable that on a second extremity of the two extremities the tension wire connects to an adjustment knob, which makes adaptation to the requirements of a particular situation easy.

In another embodiment which may have preference be- cause of the size reduction that is possible, the up-and-down movable standard is guided in a linear bearing mounted in the supporting frame.

Also then the up-and-down movable standard is prefera- bly connected with a tension wire that connects to a spring mounted on the up-and-down movable standard.

In one embodiment the tension wire is guided over at least one guide wheel, wherein said at least one guide wheel is mounted on a swivel arm which has a hinge that connects to the up-and-down movable standard and which swivel arm connects with a link to the supporting frame at a position distant from the hinge so as to fix said position in vertical direction with reference to the supporting frame.

In this embodiment it is preferred that at a position distant from the spring, the tension wire is connected to an adjustment mechanism for adjusting a tension in the tension wire .

In still another embodiment the tension wire is guided over at least one guide wheel, wherein said at least one guide wheel is mounted on the standard, which standard connects to a swivel and slide arm which has a hinge distant from the stand- ard that connects to the supporting frame so as to fix said hinge with reference to the supporting frame.

Suitably the supporting arm construction for the users arm is mounted on the horizontally movable arm through an in- termediate shoulder hinge and adapter, which shoulder hinge and adapter comprises two articulate bended linkages that in- terconnect with a central hinge, and wherein said bended link- ages on their respective sides distant from the central hinge are each provided with a further hinge that provides a swiva- ble connection with the horizontally movable arm and the sup- porting arm construction, respectively. This further promotes the adaptation of the exoskeleton to the natural posture that a user can assume.

Preferably the said hinges are lockable, to enable easy mounting or dismounting of the exoskeleton to a user.

In particular situations where a user needs his two arms to be supported by an exoskeleton, it is desirable that the exoskeleton is provided with two standards, horizontal movable arms, and supporting arm constructions that are pro- vided on the supporting frame in mirror image, and at least one back support so as to provide that the exoskeleton can in- deed support two arms of the user.

Preferably then the two horizontal arms that support the at least one back support are connected to each other with a back connector. This secures the stability of the exoskele- ton and adaptation to the user during use.

Preferably the back connector has an adjustable length to be able to tailor the exoskeleton to the user.

A further preferable feature is that the spring that connects the limb that is farthest away from the at least one back support, to the horizontally movable arm has an Y-shape wherein the branches of the Y connect to the limb, and the other side of the Y connects to the horizontally movable arm. This promotes stability and reduces the risk that breakage of the spring will lead to a collapsing exoskeleton.

Finally it is remarked that the exoskeleton only com- prises passive components, which is a competitive advantage over prior art solutions.

The invention will hereinafter be further elucidated with reference to a drawing of non-limiting exemplary embodi- ments of the exoskeleton in accordance with the invention.

In the drawing:

-figures 1, 2A, 2B and 3 show an exoskeleton of the invention in a frontal view, isometric view and side view, re- spectively;

-figures 4, 5 and 6 show back sides of three different embodiments of the exoskeleton of the invention;

-figures 7 and 8 show a detailed view at one embodi- ment of the exoskeleton of the invention;

-figures 9 and 10 show a detailed view at a second em- bodiment of the exoskeleton of the invention;

-figures 11 and 12 show a detailed view at a third em- bodiment of the exoskeleton of the invention;

-figure 13 shows a detailed view at the shoulder con- struction of the exoskeleton of the invention; and

-figure 14 shows one of the springs that is used in the exoskeleton of the invention.

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

In the figures and the following discussion the exo- skeleton will be shown as having two standards, two horizontal movable arms, one or two back supports, and two supporting arm constructions that are provided on the supporting frame in mirror image, so as to provide that the exoskeleton can sup- port two arms of an user. The skilled person will understand that for that purpose also other features that relate to sup- porting two arms of a user will be present in twofold, as the situation may require. It is however also feasible that the exoskeleton only provides a single standard, a single horizon- tally movable arm, a single back support, and a single sup- porting arm construction to provide support to only one user' s arm. To avoid any doubt it is remarked that it is not feasible that the exoskeleton will be embodied with three standards etc. It is further remarked that the exoskeleton of the inven- tion only comprises passive components and preferably avoids all motorization. It is found that the exoskeleton of the in- vention is particularly suitable for use by male persons suf- fering from Duchenne muscular dystrophy (nature discriminates between the sexes) . According to Wikipedia Duchenne muscular dystrophy is a severe type of muscular dystrophy. The symptom of muscle weakness usually begins around the age of four in boys and worsens quickly. Typically muscle loss occurs first in the thighs and pelvis followed by those of the arms. This can result in trouble standing up. Most are unable to walk by the age of 12.

With reference first to figures 1, 2A, 2B and 3 an ex- oskeleton 1 of the invention is shown in a frontal view, an isometric frontal view, an isometric back view, and a side view, respectively. The difference between figure 2A and fig- ure 2B is that the embodiment of figure 2A has two back sup- ports 5, whereas the embodiment of figure 2B only has a single back support 5. The exoskeleton 1 is used for supporting at least one arm of an user, and comprises a supporting frame 2 that supports an up-and-down movable standard 3, 3' on which a horizontally movable arm 4, 4' is mounted.

On the horizontally movable arm 4, 4 at least one back support 5, 5' is (indirectly) mounted as well as a sup- porting arm construction 6, 6' for supporting the user's arm.

The supporting arm construction 6, 6' for the users arm is mounted on the horizontally movable arm 3, 3' through an in- termediate shoulder hinge and adapter 26, 26' which is in de- tail shown in figure 13. Figure 13 shows that the shoulder hinge and adapter 26, 26' comprises two articulate bended linkages 27, 28; 27', 28' that interconnect with a central hinge 29, 29' and wherein said bended linkages 27, 28; 27',

28' on their respective sides distant from the central hinge 29, 29' are each provided with a further hinge 30, 31; 30',

31' that provides a swivable connection with the horizontally movable arm 4, 4' and the supporting arm construction 6, 6' for the user's arm, respectively. The hinges are all lockable to assist during donning and doffing of the exoskeleton.

Turning back to figures 1 - 3, it is shown that the supporting arm construction 6, 6' is articulated and extenda- ble so as to tailor the arm construction 6, 6' to the users arm dimensions. For this purpose an upper limb 7, 7' of the supporting arm construction 6, 6' comprises two telescopically extendable tubes 7.1, 7.2 as clearly shown in fig. 3a.

As is best shown in figures 2A/2B and 3, the support- ing arm construction 6, 6' has an upper limb 7, 7' and a lower limb 8, 8' that connect to each other with a hinge 9, 9' . Fig- ures 2A and 3 show that on opposite sides of the hinge 9, 9' the lower limb 8, 8' that is farthest away from the at least one back support 5, 5' connects to counterbalancing springs

10, 11; 10', 11' that on their opposite sides connect to the upper limb 7, 7' and directly or indirectly to the horizontal- ly movable arm 4, 4', respectively. Figure 14 shows the spring

11, 11' that connects the lower limb 8, 8' that is farthest away from the at least one back support 5, 5' to the horizon- tally movable arm 4, 4' . It shows that the spring 11, 11' has an Y-shape wherein the branches 37, 37' of the Y connect to the lower limb 8, 8' and the other side 33 of the Y connects to the horizontally movable arm 4, 4' .

Figure 1 and figures 2A/2B show that the limb 8, 8' that is farthest away from the at least one back support 5, 5' supports an flexible arm sleeve 34, 34' . This limb 8, 8' is further provided with an attached gripping flap 35, 35', and further with a brace 36, 36' that extends above the flexible arm sleeve 34, 34' .

Figures 2A and 2B provide a best view to show that the horizontally movable arm 4, 4' is articulated.

Figure 1 and figures 2A and 2B further show that the two horizontal arms 4, 4' that support the at least one back support 5, 5' are connected to each other with a back connect- or 32, which preferably has an adjustable length.

Turning now to a first embodiment of a construction by which the standard 3, 3' is supported by the frame 2, refer- ence is made to figures 4, 7, and 8, wherein it is shown that the up-and-down movable standard 3, 3' is supported through a parallelogram mechanism 12, 12' by the supporting frame 2.

In figure 7 it is shown that the parallelogram mecha- nism 12, 12' has guide wheels 13-15, 13' -15' that guide a ten- sion wire 16, 16' so as to provide an upward force to the par- allelogram mechanism 12, 12' . The tension wire 16, 16' has two extremities, and connects on a first extremity of the two ex- tremities to a spring 17, 17' mounted on the frame 2. On a second extremity of the two extremities the tension wire 16,

16' connects to an adjustment knob 18, 18' for adjusting the tension in the wire 16, 16' .

Figure 8 shows the up-and-down movability of the standards 3, 3' as supported according to the first embodi- ment, wherein on the left the standard 3 is moved to a lower- most position, and on the right the standard 3' is moved to a highest position.

With reference to figures 5, 9 and 10 a second embodi- ment is shown pertaining to a construction wherein the stand- ard 3, 3' is supported by the frame 2. In this second embodi- ment the up-and-down movable standard 3, 3' is guided in a linear bearing 38, 38' mounted in the supporting frame 2. Here the up-and-down movable standard 3, 3' is balanced with a ten- sion wire 16, 16' that connects to a spring 17, 17' mounted on the up-and-down movable standard 3, 3' . The tension wire 16,

16' is guided over at least one guide wheel 13, 13', wherein said at least one guide wheel 13, 13' is mounted on a swivel arm 19, 19' which has a hinge 20, 20' that connects to the up- and-down movable standard 3, 3', and which swivel arm 19, 19' connects further with a rigid link 21, 21' to the supporting frame 2 at a position 22, 22 distant from the hinge 20, 20' so as to fix said position 22, 22 with reference to the sup- porting frame 2. This is visually illustrated in figure 10 wherein the left standard 3 is moved to a lowermost position, and the right standard 3' is moved to a highest position, and wherein the positions 22, 22' at which the connections are made between the links 21, 21' and the swivel arms 19, 19' are maintained at essentially the same altitude with reference to the frame 2.

Figures 9 and 10 also show that at a position distant from the spring 17, 17' the tension wire 16, 16' is connected to an adjustment mechanism 23, 23' for adjusting a tension in the tension wire 16, 16' .

A third embodiment is shown with reference to figures 6, 11 and 12. In this third embodiment the tension wire 16,

16' is guided over at least one guide wheel 13, 13', wherein said at least one guide wheel 13, 13' is mounted on the stand- ard 3, 3', wherein said standard 3, 3' connects to a swivel and slide arm 24, 24' which has a hinge 25, 25' distant from the standard 3, 3' that connects to the supporting frame 2 so as to fix said hinge 25, 25' in altitude with reference to the supporting frame 2.

Although the invention has been discussed in the fore- going with reference to exemplary embodiments of the exoskele- ton of the invention, the invention is not restricted to these particular embodiments which can be varied in many ways with- out departing from the invention. The discussed exemplary em- bodiments 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 these exemplary embodiments. The scope of protection of the inven- tion shall therefore be construed in accordance with the ap- pended claims only, wherein a possible ambiguity in the word- ing of the claims shall be resolved using these exemplary em- bodiments .