the following illustrative embodiments are provided to illustrate the disclosure of the present invention , these and other advantages and effects can be understood by persons skilled in the art after reading the disclosure of this specification . note that the structures , proportions , sizes depicted in the accompanying figures merely serve to illustrate the disclosure of the specification to allow for comprehensive reading without a limitation to the implementation or applications of the present invention , and does not constitute any substantial technical meaning . fig1 is an overall schematic view of a surgical holder according to the present invention . the surgical holder includes a base unit 1 , a first positioning unit 2 , a second positioning unit 3 , a connecting unit 4 , a first orientating unit 5 , and a second orientating unit 6 . the base unit 1 comprises a primary link 11 and is adapted to stabilize the gravity of the surgical holder . the primary link 11 is disposed to be axially parallel to the direction of gravity horizontally disposed on the based unit 1 . please refer to fig1 in conjunction with fig2 . the first positioning unit 2 comprises a first connecting link 21 , a first auxiliary link 22 and at least a first pseudo base 23 . the second positioning unit 3 comprises a second connecting link 31 , a second auxiliary link 32 and at least a second pseudo base 33 . one end of the first positioning unit 2 is pivotally connected to the primary link 11 . one end of the first connecting link 21 and the first auxiliary link 22 pivotally connect to the primary link 11 respectively by means of a connecting component 7 , thereby allowing the first connecting link 21 to move with respect to the connecting component 7 pivotally connected to the primary link 11 for position adjustment and so as the first auxiliary link 22 . the first connecting link 21 and the first auxiliary link 22 have the same length . the first connecting link 21 and the first auxiliary link 22 are spaced apart within a distance to pivotally connect to the primary link 11 , and the distance equals to the length of the first pseudo base 23 . two ends of the first pseudo base 23 are pivotally connected to the first connecting link 21 and the first auxiliary link 22 respectively via the connecting component 7 . because the spacing distance between the first connecting link 21 and the first auxiliary link 22 equals to the length of the first pseudo base 23 , and also the first connecting link 21 and the first auxiliary link 22 have the same length , the position of the first pseudo base 23 pivotally connecting to the first connecting link 21 and the first auxiliary link 22 allow the primary link 11 , the first connecting link 21 , the first auxiliary link 22 and the first pseudo base 23 to substantially form four parallel connecting links . therefore , all the connecting components 7 of the first positioning unit 2 are axially parallel to each other . in other words , the first connecting link 21 is parallel to the first auxiliary link 22 , and the first pseudo base 23 is parallel to the primary link 11 . when the first connecting link 21 and the first auxiliary link 22 move with respect to the primary link 11 , the first pseudo base 23 will always be parallel to the primary link 11 regardless of its positions . in other words , the first pseudo base 23 would only be parallel to the gravity direction of the surgical holding device when it is operated . one end of the second positioning unit 3 is pivotally connected to the other end of the first positioning unit 2 . one end of the second connecting link 31 in the second positioning unit 3 is pivotally connected to one end in the first connecting link 21 that is not connected to the primary link 11 via the connecting component 7 , and one end of the second auxiliary link 32 in the second positioning unit 3 is pivotally connected to one end in the first auxiliary link 22 that is not connected to the primary link 11 . the second connecting link 31 and the second auxiliary link 32 have the same length , and the length of the second pseudo base 33 also equals to the first pseudo base 23 . the two ends of the second pseudo base 33 are respectively connected to the second connecting link 31 and the second auxiliary link 32 operating effect therebetween . the second connecting link 31 is parallel to the second auxiliary link 32 , the second pseudo base 33 is parallel to the primary link 11 and the first pseudo base 23 , and all connecting components 7 in the second positioning unit 3 are axially parallel to each other , so as the connecting components 7 in the first positioning unit 2 that are axially parallel to each other . when the second connecting link 31 and the second auxiliary link 32 move with respect to the first positioning unit 2 or the base unit 1 , the second pseudo base 33 will always be parallel to the primary link 11 and the first pseudo base 23 regardless of its positions . the second pseudo base 33 would only be parallel to the gravity direction of the surgical holding device when it is operated . the number of the first pseudo base 23 and the second pseudo base 33 is at least one respectively . in an embodiment , two first pseudo base 23 and two second pseudo base 33 are used , a bar 25 is disposed between the two first pseudo bases 23 for connecting the two first grounding rods 23 , and a bar 35 is disposed between the two second pseudo bases for connecting the two second pseudo bases 33 . note that the number of the first pseudo bases 23 and the second grounding rods 33 are not limited as described above . the connecting unit 4 is pivotally connected to the other end of the second positioning unit 3 . the third portions 43 of the connecting unit 4 are connected to the second connecting link 31 and the second auxiliary link 32 via two connecting components 7 . in particular , the third portions 43 of the connecting unit 4 are connected to one end of the second connecting link 31 that is not connected to the first connecting link 21 via the connecting component 7 , the third portions 43 of the connecting unit 4 are connected to one end of the second auxiliary link 32 that is not connected to the first auxiliary link 22 via the connecting component 7 , and the distance between the two joints that connect to the second connecting link 31 and the second auxiliary link 32 respectively on the third portion 43 of the connecting unit 4 and the length of the second pseudo base 33 are equal . further , all of the connecting components 7 in the connecting unit 4 are axially parallel to each other , so are the connecting components 7 in the first positioning unit 2 and the second positioning unit 3 axially parallel to each other . therefore , the third portion 43 of the connecting unit 4 , the second pseudo base 33 , the second connecting link 31 and the second auxiliary link 32 also have the effects of four parallel connecting links . in other words , the third portion 43 of the connecting unit 4 would only be parallel to the gravity direction of the surgical holding device when it is operated . summarizing above , the plurality of connecting components 7 for use in the primary link 11 , the first connecting link 21 , the first auxiliary link 22 , the first pseudo base 23 , the second connecting link 31 , the second auxiliary link 32 , the second pseudo base 33 and the connecting unit 4 are all axially parallel to each other . the end of the connecting unit 4 that is not pivotally connected to the second positioning unit 3 includes first and second portions 41 , 42 , and an included angle θ between the first and second portions 41 , 42 . the third portion 43 is perpendicular to the first and second portions 41 , 42 but is not limited to this configuration . the first portion 41 has a first shaft hole 411 that has a first shaft direction 412 . the second portion 42 has a second shaft hole 421 that has a second shaft direction 422 . the first shaft direction 412 of the first shaft hole 411 and the second shaft direction 422 of the second shaft hole 421 intersect at one point , i . e ., an intersection point 9 . therefore , the angle θ cannot be equal to 180 degrees and must be less than 180 degrees so that the first shaft direction 412 and the second shaft direction 422 can intersect at the intersection point 9 . referring to fig1 and 3 at the same time , the first orientating unit 5 includes a first orientation link 51 , a first parallel connecting link set 52 , a third pseudo base 53 and a first supporting link 54 . the second orientating unit 6 includes a second orientation link 61 , a first parallel connecting link set 62 , a fourth pseudo base 63 and a second supporting link 64 . the first orientation link 51 , the third pseudo base 53 and the first supporting link 54 collectively constitute the first orientating unit 5 via a plurality of first connecting members 56 . the second orientation link 61 , the fourth pseudo base 63 and the second supporting link 64 collectively constitute the second orientating unit 6 via a plurality of second connecting members 66 . the first orientating unit 5 is substantially symmetrical to the second orientating unit 6 . the first orientation link 51 of the first orientating unit 5 includes a first shaft 511 and a first vertical portion 512 that is perpendicular to the first shaft 511 and the first orientation link 51 . the first shaft 511 is adapted to pivotally connect to the first shaft hole 411 of the connecting unit 4 . therefore , the first orientation link 51 can rotate on the first shaft direction 412 with respect to the connecting unit 4 . the second orientation link 61 of the second orientating unit 6 also has a second shaft 611 and a second vertical portion 612 that is perpendicular to the second shaft 611 and the second orientation link 61 . the second shaft 611 is adapted to pivotally connect to the second shaft hole 421 of the connecting unit 4 . therefore , the second orientation link 61 can rotate on the second shaft direction 422 with respect to the connecting unit 4 . one end of the first parallel connecting link set 52 is pivotally connected to the first orientation link 51 . one end of the third bar 521 and the third auxiliary link 522 in the first parallel connecting link set 52 is pivotally connected to the first orientation link 51 via two first connecting components 56 respectively , while the other end of the third bar 521 and the third auxiliary link 522 are pivotally connected to the third pseudo base 53 via two first connecting components 56 . the plurality of first connecting components 56 used for the first parallel connecting link set 52 are axially parallel to each other . the length of the third bar 521 and the third auxiliary link 522 are equal , and the third bar 521 and the third auxiliary link 522 are disposed to be parallel to each other , thereby achieving four parallel bar operating effects between the third bar 521 , the third auxiliary link 522 , the first orientation link 51 and the third pseudo base 53 . the third pseudo base 53 will be parallel to the first vertical portion 512 of the first orientation link 51 in the moving processing . the first supporting link 54 is pivotally connected to the third auxiliary link 522 and the third pseudo base 53 via a connecting component 56 , and one end of the first supporting link 54 that is not pivotally connected to the third auxiliary link 522 has a first holding link 541 . the first holding link 541 is connected on the first supporting link 54 , and the shaft direction of the first holding link 541 is also parallel to the connecting components 56 . the surface of the sheath 8 has a sliding groove 81 formed thereon and a ring body 83 corresponding to the sliding groove 81 . the ring body 83 is able to slide within the sliding groove 81 . the sliding groove 81 is perpendicular to the sheath shaft direction 82 in the surface extending direction of the sheath 8 . the first holding link 541 abuts against the sliding groove 81 via the ring body 83 to slide with respect to the sliding groove 81 . one end of the second parallel connecting link set 62 is pivotally connected to the second orientation link 61 . one end of the fourth bar 621 and the fourth auxiliary link 622 in the first parallel connecting link set 62 are pivotally connected to the second orientation link 61 via two second connecting components 66 respectively , while the other end of the fourth bar 621 and the fourth auxiliary link 622 are pivotally connected to the fourth pseudo base 63 via two second connecting components 66 . the plurality of second connecting components 66 used for the second parallel connecting link set 62 are axially parallel to each other . the length of the fourth bar 621 and the fourth auxiliary link 622 are equal , and the fourth bar 621 and the fourth auxiliary link 622 are disposed to be parallel to each other , thereby achieving four parallel bar operating effects between the fourth bar 621 , the fourth auxiliary link 622 , the second orientation link 61 and the fourth pseudo base 63 . the fourth pseudo base 63 will be parallel to the second vertical portion 612 of the second orientation link 61 in the moving processing . the second supporting link 64 is pivotally connected to the fourth auxiliary link 622 and the fourth pseudo base 63 via a second connecting component 66 , and one end of the second supporting link 64 that is not pivotally connected to the fourth auxiliary link 622 has a second holding link 641 . the second holding link 641 is connected on the second supporting link 64 , and the shaft direction of the second holding link 641 is also parallel to the connecting components 66 . the second holding link 641 also abuts against the sliding groove 81 of the sheath 8 to slide within the sliding groove . the sheath 8 has an endoscope installed therein , and because the ring body 83 slides within the sliding groove 81 of the sheath 8 , the endoscope formed therein can rotate perceptively along the shaft direction 82 of the sheath 8 . the ring body 83 is connected to the first holding link 541 and the second holding link 641 respectively , which are pivotally connected to the first supporting link 54 and the second supporting link 64 respectively , allowing the sheath 8 to move on the connecting unit 4 via the first orientating unit 5 and the second orientating unit 6 . the sheath 8 can swing around right - and - left side on the connecting unit 4 via the first shaft hole 411 and the second shaft hole 421 to have a first yaw angle , and can also swing back and forth to have a second yaw angle . irrespective of the angle ( swing around or back and forth ) of swinging of the sheath 8 , the shaft direction 82 will always intersect at an intersection point 9 via the first shaft direction 412 of the first shaft 411 and the second shaft direction 422 of the second shaft 421 . the intersection point 9 is a remote center - of - motion , rcm point . because the sliding groove 81 is perpendicular to the sheath shaft 82 in the surface extending direction of the sheath 8 , when the sheath 8 rotates on the sheath shaft 82 via the sliding groove 81 , the sheath shaft 82 will not deviate from the intersection point 9 . the rcm point is a spatial fixed point along which the sheath 8 can spin around or shift to move flatly , which means that the endoscope installed in the sheath 8 will spin around along the rcm point . in laparoscopic surgery , if a surgical incision coincides with the rcm point , the installed endoscope can only rotate along the surgical incision and move forward in depth , which can prevent the expansion of wounds caused by incidental errors in lateral displacement of the operating surgeon . the first positioning unit 2 and the second positioning unit 3 are adapted to avoid the necessity of using any conventional mechanical latch connector or drive motor for locking / unlocking motions and thus achieving the static balance . referring to fig2 and 4 at the same time , the first positioning unit 2 has a first elastic element 24 disposed therein , while the second positioning unit 3 has a second elastic element 34 disposed therein . specifically , the first and second elastic elements 24 , 34 are springs , which can either be stretch or twist springs and is not limited to the embodiment shown herein . the first elastic element 24 is disposed between the first pseudo base 23 and the first auxiliary link 22 . specifically , one end of the first elastic element is connected to a spot of the first auxiliary link 22 , such as a mass center position , and the other end of the first elastic element 24 is connected to a spot of the first pseudo base 23 , such as a mass center position thereof . the second elastic element 34 is disposed between the second pseudo base 33 and the second auxiliary link 32 . specifically , one end of the second elastic element 34 is connected to a spot of the second auxiliary link 32 , such as a mass center position , and the other end of the second elastic element 34 is connected to a spot of the second pseudo base 33 , such as a mass center position thereof . in an embodiment , the mass center of the first pseudo base 23 is at the position of the bar 25 , and the mass center of the second pseudo base 33 is at the position of the bar 35 . in addition , the first and second elastic elements 24 , 34 may also use a spring with a rope as a simulated spring to become a zero free length spring but is not limited to this embodiment . the elasticity of the first and second elastic elements 24 , 34 can be obtained by means of static balance basic theory . when the surgical holder is required to maintain the state of static balance under arbitrary configurations , the elasticity of the springs is used to compensate for the changing variations of the gravity potential so that the overall potential of the mechanism is constantly maintained under any arbitrary configuration as shown in the following formula : gall indicates the overall gravity potential of the mechanism , e indicates the elasticity potential of the spring . if the elasticity of the spring is ks , and the quantity of one end of the spring connecting to the bar is m , the distance of the other end of the spring connecting to the bar is h , the length of the bar is b , and the distance of the bar mass center to other end of the bar is a , and the angle is θ , the elastic potential of the mechanism using x shaft as a standard gravity potential and the elastic potential of the spring are obtained respectively as follows : e = ½ ks ( h 2 + b 2 + 2 hb cos θ ) to achieve the state of static balance in any condition , the overall potential of the above two formulas must be constant to obtain the following formula : − mga cos θ + ½ k s ( b 2 + h 2 )+ k s bh cos θ = const because only the angle θ will vary in the process of moving , and in order for the overall potential to remain a certain value , the total items relating to 0 can be made as zero , that is : the elasticity of the spring can be obtained according to the above formula . therefore , the first positioning unit 2 and the second positioning unit 3 can use the first elastic element 24 and the second elastic element 34 to achieve the state of static balance in any arbitrary configuration . the first orientating unit 5 and the second orientating unit 6 can be assisted by the first elastic element 24 and the second elastic element 34 to enable the surgical holder to achieve the state of static balance in any arbitrary configuration . referring to fig3 and 5 at the same time , fig5 is an installation schematic view of the elastic element in the first orientating unit 5 . the first orientating unit 5 has a plurality of third elastic elements 55 installed therein . in an embodiment , the number of the third elastic elements 55 is two , one of which is disposed on the first vertical portion 512 between the first parallel connecting link set 52 and the first orientation link 51 , while the other of which is disposed at a position between the third pseudo base 53 and the first supporting link 54 . specifically , the two ends of one of the third elastic elements 55 are connected between the third auxiliary link 522 and the first vertical portion 512 respectively , and more specifically , the mass center position of the third auxiliary link 522 and the mass center position of the first vertical portion 512 . in another embodiment , the two ends of one of the third elastic elements 55 may be connected between the third bar 521 and the first vertical portion 512 respectively , and more specifically , the mass center position of the third bar 521 and the mass center position of the first vertical portion 512 but is not limited to this disclosure . the two ends of another third elastic element 55 are respectively connected at a position between the third pseudo base 53 and the first supporting link 54 . specifically , the mass center position of the third pseudo base 53 and the mass center position of the first supporting link 54 . however , the disposal of the third elastic element 55 is not limited to the mass center position as disclosed herein . the elasticity of the third elastic element can be obtained by means of the above static balance basic theory . in addition , the third elastic elements 55 may also use a spring with a rope as a simulated spring to become a zero free length spring but is not limited to this embodiment . the first orientating unit 5 and the second orientating unit 6 are symmetrical , and the installation of the elastic elements in the second orientating unit 6 is the same as in the first orientating unit 5 . the configuration of the elastic element in the second orientating unit 6 is briefly summarized as follows . the second orientating unit 6 has a plurality of fourth elastic elements 65 installed therein . in an embodiment , the number of the fourth elastic elements is two , one of which is disposed on the second vertical portion 612 between the second parallel connecting link set 62 and the second orientation link 61 , while the other of which is disposed at a position between the fourth pseudo base 63 and the second supporting link 64 . specifically , the two ends of one of the third elastic elements 65 are connected between the fourth auxiliary link 622 and the second vertical portion 612 respectively , and more specifically , the mass center position of the fourth auxiliary link 622 and the mass center position of the second vertical portion 612 . in another embodiment , the two ends of one of the fourth elastic elements 65 may be connected between the fourth bar 621 and the second vertical portion 612 respectively , and more specifically , the mass center position of the fourth bar 621 and the mass center position of the second vertical portion 612 but is not limited to this embodiment . the two ends of another fourth elastic element 65 are respectively connected at a position between the fourth pseudo base 63 and the second supporting link 64 , specifically , the mass center position of the fourth pseudo base 63 and the mass center position of the second supporting link 64 . however , the disposal of the fourth elastic element 65 is not limited to the mass center position as disclosed herein . the elasticity of the fourth elastic element can be obtained by means of the above static balance basic theory . in addition , the fourth elastic elements 65 may also use a spring with a rope as a simulated spring to become a zero free length spring but is not limited to this embodiment . therefore , the first orientating unit 5 and the second orientating unit 6 can both achieve the state of static balance by using a plurality of third and fourth elastic elements 55 , 65 respectively . summarizing above , the surgical holder according to the present invention can achieve the static balance by using a plurality of first , second third and fourth elastic elements . in addition , the first and second positioning units are adapted for positioning purposes , and the first and second orientating units are adapted for orientation purposes . the separate use of positioning and orientating units facilitates greater convenience and ease in operating the surgical holder . in the process of laparoscopic surgery , the first and second positioning units adapted for positioning purposes can be used first to move and position the endoscope installed in the surgical holder on the surgical incision of the patient to coincide the rcm point with the incision . subsequently the first and second orientating units adapted for orientation purposes can then be used to limit and guide the endoscope so that it can only rotate along the surgical incision and move forward in depth , which can prevent the expansion of wounds caused by incidental errors in lateral displacement of the operating surgeon . further , the use of elastic elements also allow the surgical holder to be maintained at the fixed position to facilitate operation without requiring conventional mechanic locking connector or any drive motor for locking / unlocking motions . it will be understood that the invention may be embodied in other specific forms without departing from the spirit or central characteristics thereof . the present examples and embodiments , therefore , are to be considered in all respects as illustrative and not restrictive , and the invention is not to be limited to the details given herein .
a surgical holder is provided , including a base unit , a first positioning unit , a second positioning unit , a connecting unit , a first orientating unit , and a second orientating unit . the first elastic element , the second elastic element , the plurality of third elastic elements and the plurality of the fourth elastic elements balance the surgical holder statically . further , the connecting unit , the first and second orientating units are designed to have rcm points which restrict lateral displacement of the surgical holder on the surgical incision to increase safety in laparoscopic operations .