Endoscopic surgical instrument coupler with manual driver for multiple sections of steerable arm

Abstract

The steerable arm 403 has two bends, each bending in a different direction. Two spools 1701 are used, each controlling a cable 1501 to tension one of the bends. To manually straighten the steerable arm 403, the drive gear 2601 can be turned to turn the spool gear of the spool 1701 to wind up the cable 1501. The drive gear can be moved out of engagement with the spool gear; and the drive gear can be moved back into engagement with the spool gear.

Description

TECHNICAL FIELD

[0001] The present invention relates to a surgical instrument configured within a larger device such as an endoscope. In particular, the present invention relates to a coupler comprising a mechanism for moving a micro robotic arm on the distal end of the surgical instrument. BACKGROUND

[0002] Figure 1 and Figure 2 are photographs of some of the early designs of mechanical surgical instruments that are still in use today for performing minimally invasive surgery. Typically, the above instruments comprise a rigid rod 103 with an end effector such as a clamp 101 which is a pair of jaws for manipulating tissue. The proximal end of the rigid rod 103 is provided with a coupler 105 for coupling the instrument to a motor box.

[0003] Inside the coupler are spools for winding and unwinding cables which pull the jaws to move the clamp 101. The base 107 of each spool is accessible outside the coupler and can be driven by a matching driver in the motor box.

[0004] The rigid rod 103 limits the use of these instruments in laparoscopic surgery which requires small incisions in the patient to insert the clamp 101.

[0005] In an improvement of these instruments, the rigid rod is replaced by a thinner, longer and flexible transmission tube. This allows the surgical instrument to be inserted into the instrument channel of an endoscope which provides access to the digestive tract through the natural orifices of the body. The transmission tube can be easily pushed through the extremely smooth instrument channel even though the endoscope is bent in several places to navigate the bends of the digestive tract.

[0006] The distal end of the above transmission tube has a micro robotic arm which can be bent and straightened by pulling or releasing cables connected to the robotic arm. The other end of these cables is attached to spools in the coupler. From this point on, this robotic arm will be referred to as a "steerable arm" to distinguish it from unrelated, possibly also compliant with the description of "robotic arm", instruments in the same technical field.

[0007] Although these surgical instruments are disposable consumables, the meaning of "disposable" includes multiple reinsertions into the endoscope during the course of a surgery.

[0008] It has been suggested that these surgical instruments are in need of further improvement. For example, the response of the manipulatable arms to cable control is often quite slow, which compromises the skill and efficiency of the surgeon using the instrument. Furthermore, the control cables in the instrument are very prone to slipping off the spool, thereby presenting the risk of emergency replacement of the surgical instrument during surgery. In addition, the common event of pulling the surgical instrument out of and reinserting it into the endoscope several times during surgery seems to very easily result in a drift in the position of the endoscope, thereby compromising the reach of the manipulatable arms. Moreover, it has been found that the instrument channel of the endoscope becomes increasingly difficult to sterilize after only a few surgeries.

[0009] It is therefore desirable to suggest one or more improvements that overcome or alleviate one or more of these problems. SUMMARY

[0010] In a first aspect, the present invention suggests a surgical instrument comprising: a manipulatable arm having a biasing to bring it into a first position; a cable; one end of the cable being connected to the manipulatable arm and the other end of the cable being connected to a spool; the spool being movable along a release direction to pay out the cable, allowing the manipulatable arm to move to the first position by the biasing; wherein the length of the cable paid out is insufficient to fully satisfy the biasing when the spool is moved to a maximum release point along the release direction.

[0011] The residual biasing provides a minimum degree of tensioning in the cable and the manipulatable arm that is always present, so that the manipulatable arm is ready to respond to a slight pulling of the cable. These features can be embodied in a device where the absolute length of the cable from the spool is insufficient to allow the biasing to fully act.

[0012] However, preferably the stop means prevents the spool from moving beyond the maximum release point to avoid paying out the cable beyond a predetermined length. The stop can be a stop, a wedge or a set of mechanically incompatible parts that prevent or stop the cable from being released beyond a certain extent.

[0013] In other embodiments, the stop can be entirely software, such as software that measures the extent to which the cable is released (or retracted by the spool) and prevents further release, or software that operates a detector for a position tag on the cable and prevents the cable from being released (or retracted by the spool) beyond the tag.

[0014] However, preferably the stop comprises a set of gears that interact up to an incompatible point in the teeth of the gears. For example, the surgical instrument further comprises a spool gear that rotates in synchrony with the spool to wind up or release the cable, the spool gear having teeth that are engaged by a drive gear for driving the spool gear to move the spool; wherein the stop means is provided by at least the absence of a notch on the tip circumference of the spool gear.

[0015] Typically, the positions where there are no teeth are flush with the tip circumference of the spool gear, i.e. the circumference defined by the tips of the other gear teeth.

[0016] Preferably, the spool gear is integral with the spool and axially aligned. Alternatively, the spool can be moved indirectly by the spool gear through a series of gears.

[0017] Preferably, the surgical instrument further comprises a one-way gear that allows the spool to move in the winding direction and prevents the spool from moving in the unwinding direction, i.e. against the bias in the steerable arm. Typically, this is provided in the form of a ratchet, but any other suitable mechanism can be used to ensure one-way movement.

[0018] In some embodiments, the spool gear as described above is a first spool gear; the spool as described above is a first spool; the cable as described above is a first cable; the surgical instrument further comprises a second spool gear that rotates in synchrony with the movement of a second spool to wind or unwind a second cable, the second spool gear having teeth that are engaged by a drive gear; wherein the drive gear is capable of driving the first and second spool gears to move the respective first and second spools to wind or unwind the respective first and second cables; and the stop means is provided at least by the absence of a notch on the second spool gear.

[0019] This allows the person to rotate multiple spool gears and the connected spools by operating only one drive gear, thereby freeing the person from having to operate the spool gears individually.

[0020] Preferably, the surgical instrument further comprises a maximum winding point that limits the moveability of the spool in the winding direction; wherein the maximum winding point is provided by a winding limit means that prevents the spool from moving beyond a predetermined winding limit. This feature prevents the steerable arm from being over-tightened and the bias from being weakened.

[0021] Preferably, the surgical instrument further comprises a spool gear that rotates in synchrony with the movement of the spool to wind or unwind the cable, the spool gear having teeth that are engaged by a drive gear for driving the spool gear to move the spool; wherein the winding limit means is provided at least by the absence of a notch on the tip circumference of the spool gear.

[0022] Typically, the drive gear is capable of disengaging the spool gear. In embodiments where there are two spool gears, the drive gear is capable of disengaging the first and second spool gears as described above. This allows the bias in the steerable arm to become the dominant force on the respective spools and cables.

[0023] Preferably, the drive gear is an annular gear with a large circumference; the spool gear has a small circumference, and the spool gear is placed inside the annular gear to mesh with the annular gear. This allows the drive gear to be firmly held and turned by all the fingers of one hand.

[0024] Preferably, the rows of gear teeth on the drive gear (i.e. the annular gear) are endless along the inner circumference of the annular gear. This feature allows the drive gear and the spool gear to easily re-engage. In a comparative embodiment, the gear teeth on the annular gear occupy a limited segment of the inner circumference of the ring. The ends of this segment are points of incompatibility with the teeth of the spool gear, which limits the extent of engagement. Similarly, the teeth of the spool gear are continuous only within a limited segment of the gear circumference. In this embodiment, the annular gear and the spool gear can be rotated to re-engage at the respective ends of the toothed segments, allowing a sufficient degree of inter-operable rotation to straighten the steerable arm.

[0025] Thus, the present invention provides the possibility of straightening the steerable arm from any curved configuration before passing the steerable arm through the instrument channel. This reduces the scratching of the instrument channel surface, which can become a habitat for difficult-to-clean germs. Furthermore, this reduces the disturbance to the position of the endoscope when passing the surgical instrument through the instrument channel, thereby making the position of the endoscope more stable.

[0026] In a second aspect, the present invention proposes a method of passing a surgical instrument through an instrument channel of an endoscope, the tip of the surgical instrument comprising a bendable and straightenable steerable arm, the method comprising the step of straightening the steerable arm before passing the surgical instrument through the instrument channel. Any bend in the steerable arm can spring back immediately once the steerable arm is outside the instrument channel.

[0027] The passing can be part of a process of inserting the surgical instrument into the instrument channel.

[0028] Alternatively, the passing can be part of a process of pulling the surgical instrument out of the instrument channel.

[0029] In a third aspect, the present invention proposes a coupler for paying out and winding up a cable to control a steerable arm, comprising: a cable; one end of the cable is connected to the steerable arm, and the other end of the cable is connected to a spool; the spool is movable along a release direction to pay out a length of the cable wound on the spool; wherein the length of the cable paid out is insufficient to fully satisfy a bias in the steerable arm when the spool is moved to a maximum release point along the release direction. That is, a minimum degree of bias provided in the steerable arm urges the steerable arm to a particular position, configuration or shape. This feature relates to a coupler provided separately from the rest of the surgical instrument.

[0030] Preferably, the stop prevents the spool from moving beyond the maximum release point.

[0031] Preferably, the coupling further comprises a spool gear that rotates in synchrony with the movement of the spool to wind or release the cable, the spool gear having teeth that are engaged by a drive gear 2601 for driving the spool gear to move the spool; wherein the stop is configured to be free of notches at least at the tip circumference of the spool gear.

[0032] Preferably, the spool gear is a first spool gear; the spool is a first spool; the cable is a first cable; the surgical instrument further comprises a second spool gear that rotates in synchrony with the movement of a second spool to wind or release a second cable, the second spool gear having teeth that are engaged by the drive gear; wherein the drive gear is capable of driving the first and second spool gears to move the respective first and second spools to wind or release the respective first and second cables; wherein the stop is configured to be free of notches at least at the second spool gear.

[0033] Typically, the drive gear is capable of disengaging from the spool gear.

[0034] Preferably, the coupling further comprises a one-way gear that allows the spool to move in the winding direction and prevents the spool from moving in the releasing direction.

[0035] Preferably, the coupling further comprises a maximum winding point that limits the mobility of the spool in the winding direction; wherein the maximum winding point is provided by a winding limit device that prevents the movement of the spool beyond a predetermined winding limit.

[0036] Preferably, the drive gear 2601 is an annular gear having a larger circumference; the spool gear has a smaller circumference, and the spool gear is placed inside the annular gear to engage the annular gear.

[0037] Typically, the gear teeth on the annular gear are endless and project towards the interior of the annular gear.

[0038] In another aspect, the present application proposes a steerable arm that is capable of being in a first position and a second position, the steerable arm being biased to the first position but prevented from fully satisfying the bias by a stop to respond quickly when urged towards the second position under the action of a force.

[0039] In another aspect, the present application provides a surgical instrument comprising: a manipulable arm having a bias to place it in a first position; a cable; one end of the cable is connected to the manipulable arm and the other end of the cable is connected to a spool; the spool is movable in a release direction to pay out the cable, allowing the manipulable arm to move to the first position by the bias; a stop prevents the spool from moving beyond a maximum release point; wherein the length of the cable paid out is insufficient to fully satisfy the bias when the spool is moved to the maximum release point in the release direction.

[0040] Preferably, the spool is movable in a wind-up direction to wind up the cable, thereby pulling the manipulable arm to a second position against the bias.

[0041] Preferably, the surgical instrument further comprises: a one-way gear that allows the spool to move in the wind-up direction and prevents the spool from moving in the release direction.

[0042] Preferably, the surgical instrument further comprises: a drive gear; a spool gear that rotates in synchronism with the spool; the drive gear is arranged to drive the spool gear; wherein the spool gear has gear teeth; and the stop comprises an interruption arranged in the gear teeth of the spool gear that prevents the drive gear from moving further.

[0043] Preferably, the spool gear is a first spool gear; the spool is a first spool; the cable is a first cable; the stop is a first stop; the surgical instrument further comprises: a second spool gear; a second spool; a second cable; a second stop; the manipulable arm has a second bias to place it in a third position; one end of the second cable is connected to the manipulable arm and the other end of the second cable is connected to the second spool; the second spool is movable in a release direction to pay out the second cable, allowing the manipulable arm to move to the third position by the second bias; wherein the length of the second cable paid out is insufficient to fully satisfy the second bias when the second spool is moved to a maximum release point in the release direction; the second spool is movable in a wind-up direction to wind up the second cable, thereby pulling the manipulable arm to a fourth position against the second bias; the second spool gear is rotatable in synchronism with the second spool; the drive gear is arranged to drive the second spool gear; wherein the second spool gear has gear teeth; and the second stop comprises an interruption arranged in the gear teeth of the second spool gear that prevents the drive gear from moving further.

[0044] Preferably, the surgical instrument further comprises: a wind-up limit that prevents the spool from moving beyond a maximum wind-up point in the wind-up direction.

[0045] Preferably, the surgical instrument further comprises: a drive gear; a spool gear that rotates in synchronization with the spool; the drive gear is configured to drive the spool gear; wherein the drive gear is capable of disengaging the spool gear so that the steerable arm is free to move to the first position according to the bias.

[0046] Preferably, the drive gear is a ring gear that surrounds the spool gear; the ring gear comprises: a ring having an outer edge and an inner edge; gear teeth disposed on the inner edge that engage the gear teeth of the spool gear so that turning the ring drives the spool gear.

[0047] In another aspect, the present invention proposes a coupling for paying out and winding up a cable to control a steerable arm, comprising: a spool for the cable; the spool is movable along a pay-out direction to pay out the cable; a stop device that prevents the spool from moving beyond a maximum pay-out point; a drive gear; a spool gear that rotates in synchronization with the spool; the drive gear is configured to drive the spool gear; wherein the spool gear has gear teeth; the stop device comprises an interruption disposed in the gear of the spool gear that prevents the drive gear from moving further.

[0048] Preferably, the drive gear is capable of disengaging the spool gear so that the spool is free to move without the drive gear.

[0049] Preferably, the spool is movable along a winding-up direction to wind up the cable; a winding-up limit device is included that prevents the spool from moving beyond a maximum winding-up point along the winding-up direction.

[0050] Preferably, the drive gear is a ring gear that surrounds the spool gear; the ring gear comprises: a ring having an outer edge and an inner edge; gear teeth disposed on the inner edge that engage the gear teeth of the spool gear so that turning the ring drives the spool gear. BRIEF DESCRIPTION OF DRAWINGS

[0051] The present invention will be further described with reference to the attached drawings in which:

[0052] Figure 1 (Fig. 1) is a photograph of an instrument with a coupling connected to a mechanical driver from the da Vinci system of Intuitive Surgical, Inc.;

[0053] Figure 2 (Fig. 2) is another photograph of the instrument in Figure 1 (Fig. 3) is another photograph of the instrument in

[0054] Figure 3 is a perspective view of a coupler as an embodiment of the present invention;

[0055] Figure 4 is a schematic view of a surgical instrument comprising Figure 3 a coupler;

[0056] Figure 5 is a photograph of a surgical instrument as shown in Figure 4 ;

[0057] Figure 6 shows two Figure 4 surgical instruments inserted into an endoscope as shown in ;

[0058] Figure 7 is an enlarged view of an inset in Figure 6 , showing the tip of the endoscope of Figure 6 ;

[0059] Figure 8 shows the equipment for endoscopic surgery using the surgical instrument of Figure 4 ;

[0060] Figure 9 shows the motor housing of the coupler to which the surgical instrument of Figure 4 can be attached;

[0061] Figure 10 is an enlarged view of the coupler socket on the motor housing of Figure 9 ;

[0062] Figure 11 shows the coupler socket of Figure 10 and the coupler not attached;

[0063] Figure 12 shows the body of a steerable arm, such as the steerable arm provided at the distal end of the surgical instrument of Figure 4 ;

[0064] Figure 13 shows a steerable arm which can be provided at the distal end of the surgical instrument of Figure 4 and has a bend in the steerable arm body;

[0065] Figure 14 shows the steerable arm of Figure 13 tensed or articulated straight;

[0066] Figure 15 shows how the bend body of the steerable arm of Figure 13 is straightened by pulling the control cable;

[0067] Figure 16 is a bottom view of the coupler as shown in Figure 3 ;

[0068] Figure 17a is Figure 3 an exploded view of the coupler shown in

[0069] Figure 17b is an exploded view of the components of the spool shown in Figure 3 together with the base of the coupler of

[0070] Figure 18 is another exploded view of the components of the spool, but without the rest of the coupler;

[0071] Figure 19 shows the spool assembled from the components shown in Figure 18

[0072] Figure 20 shows the spool in Figure 4 with the cables attached for controlling the steerable arms of the surgical instrument shown in Figure 19

[0073] Figure 21 shows the coupler of Figure 3 without the coupler housing, showing the coupler base and the spout extending from the coupler base;

[0074] Figure 22 shows the base portion of the spout shown in Figure 21

[0075] Figure 23 is a top view of the base portion of the spout shown in Figure 22

[0076] Figure 24 is a cross-sectional view of the base portion of the spout shown in Figure 22

[0077] Figure 25 shows how the spool in the coupler of Figure 3 can be prevented from releasing all of the cable by using a stop;

[0078] Figure 26 shows how the spool gear shown in Figure 27 can be driven by the drive gear 2601 through a pinion gear;

[0079] Figure 27 shows the stop, which is provided in the form of a toothless portion along the arrangement of gear teeth on the spool gear;

[0080] Figure 28 shows how the drive gear 2601 shown in Figure 27 can be disengaged from the pinion gear;

[0081] ​​​​​Figure 29 shows how the pinion in Figure 26 can drive two different spools at the same time, each spool straightening a different bend in the steerable arm;

[0082] Figure 30 shows the stage of inserting the coupler in Figure 26 into the coupler socket of the motor box;

[0083] Figure 31 shows the base of another coupler as a further embodiment, as Figure 26 a replacement for the embodiment shown in

[0084] Figure 32 shows how the ring gear in Figure 31 can drive the spool gear;

[0085] Figure 33 shows how the ring gear of Figure 31 is disengaged from the spool gear;

[0086] Figure 34a shows how the ring gear in Figure 31 can drive the spool gear;

[0087] Figure 34b shows how the ring gear in Figure 31 is received inside the coupler socket of the motor box;

[0088] Figure 35 shows the base of yet another coupler as a further embodiment, having a ring gear different from the one shown in Figure 31 . DETAILED DESCRIPTION

[0089] Figure 3 is a perspective view of the coupler 301 of the surgical instrument 401. The coupler 301 has a dome-shaped housing 303 placed over a coupler base 305. The housing 303 is made of two side parts 303a, 303b. The bottom 307 of the coupler base 305 is relatively flat and provides access to control the spools inside the housing 303. Figure 3 The orientation shown in is used as a position reference in the rest of this description.

[0090] Figure 4 shows the surgical instrument 401 having a transfer tube 405 as a main body. The transfer tube 405 typically has a length of 0.5m to 1.8m. The coupler is located on the proximal end of the surgical instrument 401 and the steerable arm 403 is located on the distal end.

[0091] Manipulator arm 403 is a hollow tubular device that is approximately 3 cm long when fully extended and can bend and straighten, swing left and right, or shorten and lengthen when pulled by a cable attached to the inner surface of manipulator arm 403. The cable passes through transmission tube 405 and is connected to a spool inside coupler 301.

[0092] Figure 5 is a photograph of a prototype of surgical instrument 401 , provided here so that the reader can understand the relative size of maneuverable arm 403 and the rest of surgical instrument 401 .

[0093] Figure 6 An endoscope 601 is shown having two instrument channels 609 therein each having a surgical instrument 401 inserted through a respective opening near the proximal end of the endoscope 601 where a controller 607 for operating the endoscope body is located.

[0094] Figure 7 yes Figure 6 6 shows an enlarged view of the endoscope tip 603 as an insertion portion. The endoscope tip 603 has a light source 701 and a camera 703. The distal openings of two instrument channels 609 can be seen, each of which extends from a maneuverable arm 403 of a surgical instrument 401. Each maneuverable arm 403 has an end effector 605 at its distal end.

[0095] Figure 8 A possible setup for endoscopic operation is shown, where an endoscope 601 is supported by a telescopic arm 803 extending from a trolley 801. The white arrow points to a motor box 805 on the trolley 801. The motor box has a coupler socket into which the coupler 301 can be inserted. However, in Figure 8 The middle coupler receptacle is hidden from view by the motor case cover 802.

[0096] Figure 9 805 after the motor housing cover 802 has been removed, showing the two coupler sockets 901. As shown, the coupler socket 901 on the right side has the coupler 301 with the surgical instrument 401 inserted therein. The transmission tube 405 can be seen extending from the tip of the coupler 301.

[0097] Figure 10 is a close-up view of coupler receptacle 901. Figure 11 A similar view is given, but also showing the bottom 307 of the coupler 301 .

[0098] The coupler socket 901 comprises a short cylindrical housing, the diameter and height of which are suitable for holding the coupler 301 by the coupler base 305. The coupler 301 is inserted into the coupler socket 901 and held by two snap clamps 1003, so that the motor box programmatically controls the spools and cables in the surgical instrument 401. At the depth of the housing there are four spool drives, each of which is a female rod receptacle 1001 for cooperating with a corresponding male spool rod 1101 on the base of each spool.

[0099] Figure 3 Two buttons 309 are shown, disposed on opposite sides of the coupler housing 303. Pressing the buttons 309 releases the snap clamps 1003. This allows the coupler 301 to be pulled out of the coupler socket 901.

[0100] The spool rods 1101 can be twisted to rotate the spools to wind up the cables and straighten the steerable arms 403, or to release the cables to bend the steerable arms 403. That is, the surgeon can manually twist the spool rods 1101 with one hand while holding the coupler 301 with the other hand. Alternatively and preferably, the coupler 301 is inserted into the coupler socket 901 so that the motor box 805 can programmatically control each spool.

[0101] At the start of the procedure, the endoscope 601 is inserted by the tip 603 into the mouth or rectum of an anaesthetised or sedated patient. The endoscope 601 is bent by the bends of the alimentary canal, moved to the surgical target on the alimentary canal. The brakes (not shown) on the wheels 807 of the trolley 801 can be applied to prevent the trolley 801 from moving. After the endoscope reaches the target site and is stably placed, the surgical instrument 401 can be inserted into the endoscope.

[0102] The coupler 301 of the first surgical instrument 401 is then inserted into the coupler socket 901. Subsequently, the software of the motor box is run to turn the appropriate female rod receptacle 1001 to rotate the spool rod 1101 and straighten the steerable arm 403.

[0103] The straightened steerable arm is inserted into one of the instrument channels 609 and is advanced through the delivery tube 405 until the steerable arm 403 emerges from the endoscope tip 603.

[0104] Straightening the steerable arm 403 before insertion into the instrument channel 609 reduces the friction and resistance of the steerable arm 403 as it passes through the instrument channel 609. It is now easier to insert the surgical instrument 401 through the endoscope than if the same operation were performed using an unstraightened steerable arm 403. This benefit is even more pronounced if one considers how the surface of the instrument channel 609 can be protected from being cut by the sharp thermoknife at the end of the straightened steerable arm 403.

[0105] As a result, there is less scraping and cutting on the instrument channel 609, fewer crevices for bacteria to hide and breed, and improved efficiency of endoscope sterilization. Thus, even if the surgical instrument 401 is inserted into or removed from the instrument channel without reducing the intensity of daily use, the wear and tear of the instrument channel can be slower, making it possible for the endoscope to have a longer and more robust service life.

[0106] Furthermore, reducing the drag and scraping on the instrument channel 609 also reduces the likelihood of forceful tugging on the endoscope 601. This helps keep the endoscope tip 603 as stable as possible, even if the surgeon frequently changes surgical instruments during the procedure.

[0107] At a distance of Figure 8 From a location not far from the equipment, the surgeon performs virtual surgical movements based on real-time images transmitted by the camera 703 to a display (not shown) using a hand-held remote control. The virtual surgical movements are detected by a wireless detector in the cart as movement coordinates, which are programmatically converted by a processor in the motor box 805 into movements of the steerable arm 403 and the end effector 605.

[0108] The end effector 605 determines the function of the surgical instrument 401, which can be a pair of forceps, a diathermy knife, an injection needle, a suturing tool, etc. The surgical instrument 401 with different end effectors 605 can be removed and reinserted from the endoscope 601 multiple times during the surgical operation, with the aim of using the end effector 605 as a painter repeatedly picks and uses the same brush.

[0109] Figure 12 The body 1201 of the steerable arm 403 is shown without the end effector 605, cables, and transmission tube 405. The body is made from a straight and hollow tube of a high-elasticity metal alloy such as Nitinol. The length of the body is about 3 to 3.5 cm, and the diameter is between 2.5 to 3.5 mm, so as to fit into the instrument channel 609 of most endoscopes.

[0110] The tube is laser cut to provide a series of separate ribs 1203 on one side of the tube 1201. The other side of the tube becomes a spine 1205 to which the ribs 1203 are attached. When the tube 1201 is bent on the side towards the spine 1205, the ribs 1203 flare out. The bent tube 1201 is then held stationary, heat treated, and cooled so that the bend becomes a permanent shape of the tube in the static state. This provides a concave spine side and a convex rib side.

[0111] Being made from a single hollow tube of a high-elasticity metal alloy and having such small dimensions, the steerable arm 403 provides the structural strength and shape elasticity of a continuum structure.

[0112] Figure 13 A steerable arm 403 made of a curved tube 1201 is shown, with an end effector 605 fixed to it. The proximal end of the steerable arm 403, called the shoulder 1301, is attached to the transfer tube in a way that the hollow core in the steerable arm 403 aligns with the core of the transfer tube 405. This allows one end of the cable attached to the inner surface of the steerable arm 403 to pass through the transfer tube and be attached to a spool in the coupler 301. Figure 14 A straightened and articulated steerable arm 403 is shown, which occurs when the cable is wound up by the spool.

[0113] Typically, the end effector 605 is controlled by another cable attached to another spool in the coupler 301, and the shoulder 1301 is controlled by yet another cable attached to yet another spool in the coupler 301, to make the steerable arm 403 rotate left and right on the transfer tube. However, the rest of this specification focuses on the features of the coupler 301 that allow the straightening of the steerable arm 403 before passing through the instrument channel, which can reduce the displacement of the endoscope tip, reduce the scratching of the instrument channel, and maintain the efficiency of sterilization.

[0114] Figure 15 is a series of illustrations of the articulation of a resiliently curved steerable arm 403. The ends of the cable inside the core of the steerable arm 403 are connected to the ribs 1203 near the distal end of the steerable arm 403. The cable 1501 extends out of the steerable arm 403, through the transfer tube 405, and is tied to a control spool in the coupler 301. Figure 15 The leftmost illustration in shows the steerable arm 403 in a static state, where the spine 1205 side is concave ( Figure 15 (a) in). The ribs 1203 are on the convex side and are spread out to accommodate the curvature. When the cable 1501 is wound up by the spool, some of the ribs 1203 get closer to each other, while the spine 1205 tightens and straightens out ( Figure 15 (b) in). Winding up more of the cable 1501 pulls the ribs 1203 closer to each other, and even reverses the curvature of the steerable arm 403 to bend towards the opposite side ( Figure 15 (c) in). Releasing control of the control spool allows the bias in the steerable arm 403 to become the dominant force on the spool, causing the steerable arm 403 to spring back to the curved shape. This bias makes it unnecessary to use any counter-cable; a single cable 1501 is enough to tense the steerable arm 403.

[0115] Figure 16 The bottom 307 of the coupler 301 is shown, where the shaft base 1601 of the spool can be accessed to control the spool.

[0116] Figure 17ais an exploded view of the coupler 301 showing the two side portions 303a, 303b of the housing 303 separated from each other and the coupler base 305. Four spools 1701 can be seen, each spool 1701 being disposed in a respective axle hole in the coupler base 305. A mouth 1703 extends upward from the center of the coupler base 305 between the spools 1701. The mouth 1703 has a top portion 1705 and a bottom portion 1707. The top portion of the mouth 1703 is referred to as the transmission tube holder 1705, which holds the transmission tube tightly while allowing the cable within the transmission tube to slide. In the assembled coupler 301, the transmission tube holder 1705 protrudes slightly from the opening in the top of the housing 303 (in Figure 3 also can be seen).

[0117] Figure 17b is an exploded view of the spool 1701 showing the components in alignment with the axle hole 1717 in the coupler base 305. Typically, the spool 1701 includes a spool shaft 1715 and various winding components 1709. A bearing 1711 is disposed for insertion from the bottom 307 into the axle hole 1717, and a constriction (not visible) midway along the axle hole 1717 prevents the bearing 1711 from passing completely through. Another bearing 1711 is disposed for insertion from the top into the axle hole 1717, and also does not pass completely through due to the constriction.

[0118] To assemble the spool 1701, the spool shaft 1715 is inserted from the bottom 307, through the axle hole 1717 and both bearings 1711, passing through the constriction. The spool shaft 1715 has a shaft base 1601 that is larger than the axle hole 1717, so it covers the axle hole 1717. The spool rod 1101 extends from the shaft base 1601, thereby being accessible from the outside of the coupler 301.

[0119] Figure 18 shows the winding components 1709 assembled onto the spool shaft 1715, i.e., the portion of the spool shaft 1715 that has extended through the coupler base 305.

[0120] Figure 19 shows the assembled spool 1701, which has two line winders 2501. Each of the two line winders 2501 includes a wide, gentle ramp that prevents the attached cable 1501 from slipping out of the line winder 2501 in the event of low line tension. Optionally, each line winder 2501 can have attached to it the end of a different cable 1501, in which case turning the spool 1701 can wind up or pay out both cables 1501 simultaneously. Alternatively, having two line winders is also useful if reverse cable is needed for some reason. For example, Figure 20It is shown that a certain length of cable has been wound on the top reel, while the bottom reel is only connected to the end of another cable. Rotating the spool 1701 releases the cable from the top reel will simultaneously wind the cable around the bottom reel. Reversing the direction of rotation will wind the cable around the top reel and release the cable from the bottom reel.

[0121] Figure 18 The shown winding parts 1709 include a lower left winding part 1709a and a lower right winding part 1709b. The lower right winding part 1709b has a loop for placing on the spool shaft 1715. Below the loop is a gap into which the lower left winding part 1709a is mounted radially. When fixed together with screws, these parts are held tightly on the bottom of the spool shaft 1715. In addition, there are an upper left winding part 1709c and an upper right winding part 1709d with the same, but vertically reversed, configuration, so that the loop on the upper left winding part 1709c is placed above the spool shaft 1715, the gap of the upper left winding part 1709c is closed by the upper right winding part 1709d, and held tightly on the upper part of the spool shaft 1715 with screws.

[0122] Figure 21 Both the left and right figures show the coupler base 305 and the mouth 1703 without any spools 1701. The left figure also shows some bearings 1711 placed in the respective shaft holes 1717. The right figure is an exploded view of the mouth 1703, showing the bearings 1711 separate from the shaft holes 1717.

[0123] The bottom part of the mouth 1703 is called the mouth base 2101, and as already mentioned in the previous paragraph, the top part is called the transport tube holder 1705.

[0124] The lower end of the transport tube holder 1705 has a horizontally outwardly extending square skirt with corners having a rotation hole 2103 that can be aligned with the respective shaft hole 1717, into which the rotation tip 1713 at the top of each spool shaft 1715 can be inserted and held without restraint or rotatably (see Figure 17a ).

[0125] As shown in the right figure in Figure 21 , the transport tube holder 1705 itself includes two side parts 1705a, 1705b. Each part provides a lateral half of the passage 2105. The passage 2105 is aligned with the center of the coupler base 305, providing a narrow channel that urges the cable 1501 towards the center of the mouth base 2101, in other words, if there is more than one cable 1501.

[0126] Figure 22 is a perspective view of the mouth base 2101, Figure 23is the corresponding plan view, Figure 24 The lower end of the mouth 1703 has four toes 2201 extending in different directions. Each toe 2201 has a screw hole to allow a screw to secure the toe 2201 to the coupler base 305.

[0127] The top of the mouth base 2101 has four lugs 2203 extending in different directions. Each lug 2203 is provided with a screw hole that can be aligned with a corresponding hole 2107 in the skirt of the transfer tube holder 1705 for fastening the transfer tube holder 1705 to the mouth base 2101.

[0128] The cables 1501 that extend from the transfer tube 405 pass through the passageways 2105. At a deeper part of the mouth, each cable passes into a different slot 2301 within the mouth base 2101 to ensure cable separation before each cable 1501 is guided to the spool 1701 by turning around the respective roller shaft 2205. The slots are simply narrow passages into which the cables pass. Two of the slots can be seen in Figure 23.

[0129] Although Figure 17a Four spools 1701 are shown in Figure 22, but in other embodiments there can be more or fewer spools 1701 depending on the number of controllable components in the steerable arm 403 that require cable control. A corresponding number of rod receivers 1001 on the spools 1701 need to be provided in the coupler socket 901.

[0130] Pre-tensioned stop or stopper 1

[0131] When the steerable arm moves from straight to curved, the spool must release a length of cable to allow the bend. The spool (and the reel) are dimensioned so that the required length is released without the need for the spool to rotate fully. Since the steerable arm 403 is only about 3cm in length, this required length of cable tends to be much shorter.

[0132] Figure 16 The bottom of the coupler 301 is shown where the four shaft bases 1601 can be accessed to rotate the respective spools within the coupler. From the edge of each shaft base 1601 extends a protrusion 1603. In addition, next to each shaft base 1601 is a stop 1605 that is also provided on the coupler bottom 307.

[0133] Each stop is located in the path of the respective tab 1603 when the corresponding spool 1701 is rotated to release cable. Thus, the stops limit the extent to which the spool can rotate. The stops are positioned to prevent a certain length of cable from being released. More precisely, the stops are positioned so that the maximum length of cable that the spool 1701 can release is slightly less than enough to allow the manipulatable arm to fully flex under the urging of the bias. The unfulfilled bias continuously pulls on the cable, which provides a minimum amount of pretension in both the cable 1501 and the flexed manipulatable arm 403. This allows the manipulatable arm to respond immediately whenever the spool is rotated in the opposite direction to wind up the cable.

[0134] Figure 25 is a schematic illustration of how the stops work. Figure 25 The upper drawing in Figure 25 shows the spool 1701 with no stops inserted into the adjacent stub hole 2503. To facilitate the illustration, a wing 2501 is drawn extending radially from the body of the spool 1701 instead of the tab 1603 extending from the shaft base 1601 located on the other side of the coupler base 305. The wing 2501 rotates around the spool 1701 as the spool 1701 is rotated.

[0135] Figure 25 The lower drawing in Figure 25 shows a stop inserted into one of the stub holes 2503. The position of the stop 1605 prevents the spool 1701 from paying out the length of cable 1501 needed to fully satisfy the bias. Preferably, the maximum length of cable 1501 that the spool can release allows the manipulatable arm 403 to almost fully exhibit flexion, except for a small degree that is imperceptible to the human eye.

[0136] Although the embodiments described so far have manipulatable arms 403 that are flexed in the static state, other embodiments (not shown) are possible in which the manipulatable arms 403 are biased straight in the static state. The straight manipulatable arms 403 can be flexed to one side by pulling on the cable 1501 on the distally located ribs 1203 within the manipulatable arm 403. The pulling causes the gaps between the ribs to close and the manipulatable arm to flex to the side of the ribs. Even in such embodiments, the manipulatable arms 403 can be pretensioned by pulling to flex to the side of the ribs, but the pretensioning is slight enough that the flexion is imperceptible to the human eye.

[0137] Referring again to the embodiments of the manipulatable arms 403 that are biased to be flexed, depending on the dimensions and materials of the manipulatable arms, some manipulatable arms can be over-tensioned, which can weaken the strength of the bias. To provide an upper limit to the tensioning (i.e., winding up of the cable) of the manipulatable arms 403, a small stop block 2505 can be used instead of the stops 1605. The inset in Figure 25 shows the stop block 2505, which is not to scale, with a white arrow.

[0138] The stopper block 2505 is preferably arcuate to match the curvature of the path of the wing 2501. The base of the stopper block 2505 can be provided with two short stakes for mounting into respective short stake holes 2503.

[0139] The stopper block 2505 has two ends and a distance between the two ends. The end of the stopper block 2505 against the wing rotating in the cable release direction prevents the cable 1501 from being released completely. The other end of the stopper block 2505 against the wing rotating in the opposite direction prevents the steerable arm 403 from being over-tightened.

[0140] Preferably, all components of the coupler base 305 are made of hard plastic material.

[0141] Pre-tensioned stop or stopper 2

[0142] Other embodiments including a limitation on the rotation of the spool are possible. Figures 26-30 One such other embodiment is shown.

[0143] Figure 26 The bottom of the coupler 301 is shown, wherein the drive gear 2601 is provided in the center of the circular coupler base 305. The spool 1701 is shown on the top side of the coupler base 305. On the bottom side of the coupler base 305, the shaft base 1601 of the spool 1701 is provided with a spool gear 2701. The spool gear 2701 is in mesh with the drive gear 2601 via an intermediate pinion 2603.

[0144] Figure 27 The spool gear 2701 is shown separately. On the surface of the spool gear 2701, a spool rod 1101 is provided for mating with a corresponding rod receptacle 1001 when the coupler 301 is inserted into the motor box 805.

[0145] In general, any gear is made of circumferentially arranged teeth, which are made by cutting or forming notches in the circumference of the gear to define the gear teeth. The root of the tooth is aligned with a root circumference defined by a root diameter, while the tip of the tooth is aligned with a tip circumference or outer circumference defined by a tip diameter. If the gear is an annular gear, i.e. an annulus with the inner circumference provided with gear teeth pointing inwards, the root circumference will be larger than the tip circumference.

[0146] A portion of the spool gear 2701 is not provided with an opening, i.e. there is a toothless region 2703 that lacks at least one gear tooth. Because there is no opening, the toothless region is flush with the outer diameter or tip circumference of the spool gear 2701. One end of this toothless region 2703 cannot engage the teeth of the pinion 2603. This end limits the rotation of the spool in the cable release direction to prevent the cable 1501 from releasing completely, so as to provide a pre-tension in the cable 1501 and steerable arm 403. The other end of the toothless region limits the steerable arm 403 from over-tensioning.

[0147] Figure 28 A side view of the drive gear 2601 is shown. The drive gear 2601 also has a shaft extending therefrom that the surgeon can use to manually twist the drive gear 2601. This shaft is referred to as the driver shaft 2801 for distinction. Typically, the drive gear 2601 is used only by the surgeon and not driven by the motor box.

[0148] The drive gear 2601 has a set of upper gear teeth 2803 and a set of lower gear teeth 2805. The upper gear teeth 2803 engage the ratchet 2807 on the coupler bottom 307 to prevent the bias in the steerable arm from pulling the drive gear 2601 in the release direction. This allows the surgeon to lift and reposition his hand to continue twisting the drive gear 2601, or to free his hand to insert a surgical instrument into the endoscope 601. The lower gear teeth 2805 engage the pinion 2603 to turn the spool gear 2701.

[0149] The surgeon can twist the driver shaft 2801 to straighten the steerable arm 403 before passing the steerable arm through the instrument channel 609 of the endoscope 601.

[0150] The drive gear 2601 can be switched between two positions. Figure 28 The right image of Figure 2 shows the drive gear 2601 lifted from the coupler bottom 307, with the lower gear teeth 2805 engaging the pinion 2603 and the upper gear teeth 2803 engaging the ratchet 2807.

[0151] Pressing the drive gear 2601 down towards the coupler bottom 307 disengages the drive gear 2601 from both the pinion 2603 and the ratchet 2807, and thus also from the spool 1701. This allows the bias in the steerable arm 403 to become the dominant force on the spool 1701. As the disengaged spool 1701 is free to rotate in response to the bias, the length of the cable 1501 needed to accommodate the performance of the bend will be pulled off the spool 1701, except for a very short length that is prevented from releasing. This release limit is provided by the abutment between the relevant end of the toothless region 2703 on the spool gear 2701 and the pinion 2603. Thus, this end of the toothless region acts like a ratchet to prevent the spool 1701 from rotating in the release direction. Figure 25The pinion 2603 is similar to the stop 1605.

[0152] Typically, a spring (not shown) is provided to bias the drive gear 2601 back to the raised position when the force pressing on the drive gear 2601 is lifted.

[0153] When the drive gear 2601 is raised, the pinion 2603 will still mesh with the spool gear 2701. Thus, after re-meshing the drive gear 2601, the toothless region 2703 abuts the pinion 2603 in the same position.

[0154] Figure 29 The left drawing of Fig. 4 shows the steerable arm 403 with two bends, marked by white arrows, each bend bending in a different direction. Two spools 1701 (one hidden from view) are used, each spool 1701 controlling one cable 1501 to tighten one of the bends. To manually straighten the steerable arm 403, the surgeon twists the centrally located driver rod 2801 on the coupler bottom 307 while turning both spools 1701 to wind up the cables 1501. The right drawing shows the two straightened bends. The change in orientation of the rod from the left drawing to the right drawing shows the rotation of the drive gear 2601 and the spool gear 2701.

[0155] For the avoidance of doubt, in a coupler 301 with four spools 1701, there are four pinions 2603. Each pinion 2603 meshes with a different side of the same drive gear 2601. Thus, the driver rod 2801 rotates all four spools 1701. Typically, the cables, spools and gears are pre-configured such that when the drive gear 2601 disengages the spool gear 2701, the bias in the steerable arm 403 pulls the spools 1701 into an orientation in which the spool rods 1101 line up to fit smoothly into the rod receptacle 1001 in the motor box 805.

[0156] Figure 30 Different stages of engagement of the coupler socket 901, which engages the motor box 805, and the coupler 301 are shown. The top drawing shows stage 1, in which the surgical instrument 401 has straightened steerable arms 403. This can be done by the surgeon twisting the driver rod 2801. The ratchet prevents the straightened steerable arms 401 from springing back to the bent state. The coupler 301 is pushed into the coupler socket 901 by the coupler bottom 307.

[0157] The tapper 3001 protrudes from the depth of the coupler socket 901 beyond the rod receiving portion 1001. The middle drawing shows stage 2, where the tapper 3001 presses on the drive gear 2601, disengaging the spool gear 2701 and causing the steerable arm 403 to immediately return to a curved shape. The bottom drawing shows stage 3, during which the spool rod 1101 cooperates with the rod receiving portion 1001, allowing the motor housing 805 to independently drive each spool 1701. Two snap-on clamps 1003 securely hold the coupler 301 in the coupler socket 901 until released by pressing the button 309.

[0158] When so inserted into the motor housing 805, the steerable arm 403 can be straightened by manipulating the motor housing 805 for each spool 1701. However, when the motor housing 805 is inoperable due to a power outage, it is useful to be able to manually twist the driver rod 2801.

[0159] Pre-tensioned stop or stopper 3

[0160] Figure 31 、 Figure 32 、 Figure 33 and Figures 34a-34b is a drawing of yet another embodiment, in which a ring gear 3101 replaces the central drive gear 2601 in the embodiment of Figure 26 .

[0161] The ring gear 3101 comprises a ring, which is a circular, endless loop, typically made of the same material as the rest of the coupler 301. The circumference of the ring has a width such that the outer rim has a slightly larger diameter than the coupler base to provide better grip. The inner rim has a smaller circumference. On opposite sides of the inner rim are provided two rows of drive teeth 3103 extending inwardly, each row of drive teeth 3103 being able to engage and drive an adjacent spool gear 2701.

[0162] For the same reason of preventing the surgeon from manually winding up the cable and automatically releasing it, a row of fine teeth 3105 is provided on the inner rim and immediately adjacent to each row of drive teeth 3103 on the clockwise side, engaging a ratchet on the coupler bottom 307. Only one ratchet gear is needed. Thus, the ratchet on the coupler bottom 307 only engages either of the two rows of fine teeth shown. In some embodiments, there is only one such row of fine teeth on the ring gear 3101.

[0163] In Figures 31-34a -34b, each spool gear 2701 has two toothless areas at both ends. Since there is no cutout, the toothless areas are flush with the outer diameter or tip circumference of the spool gear 2701.

[0164] When the spool gear 2701 is rotated to a position where one of these end portions abuts against the drive tooth 3103, further rotation of the spool 1701 in the same direction is prevented; the spool gear 2701 has no teeth in this toothless region that intersect and move with the corresponding teeth on the ring gear 3101.

[0165] The ring gear 3101 can be switched between a lifted position where it engages the spool gear 2701 and the ratchet 2807 and a depressed position where it disengages the spool gear 2701 and the ratchet 2807.

[0166] Figure 32 The ring gear 3101 is shown in the lifted position (top diagram) and rotated counterclockwise to drive both spool gears counterclockwise (bottom left diagram to bottom right diagram). This winds the respective cables around the connected spools 1701 and straightens the steerable arm 403 (not shown). However, the counterclockwise end of the toothless region on each spool gear 2701 abuts against the respective drive tooth 3103, which prevents further rotation and over-tightening of the steerable arm 403. As shown, the rotation of the spools 1701 in the Figure 32 can be seen from the change in the orientation of the spool shafts 1101. Since there are two cables controlled by different spools 1701, the reader can conclude that the steerable arm 403 has two bends.

[0167] Figure 33 The ring gear 3101 is shown in the lifted position (top diagram) and rotated counterclockwise to drive both spool gears counterclockwise (bottom left diagram to bottom right diagram). This winds the respective cables around the connected spools 1701 and straightens the steerable arm 403 (not shown). However, the counterclockwise end of the toothless region on each spool gear 2701 abuts against the respective drive tooth 3103, which prevents further rotation and over-tightening of the steerable arm 403. As shown, the rotation of the spools 1701 in the Figure 32 The straightened steerable arm 403 is now free to spring back to its permanent shape, a shape with two bends formed by the biasing force in each bend. Rotating the spools 1701 in the release direction, each cable 1501 is pulled away from the respective spool 1701 by the required length to accommodate the bend (not shown). However, each spool can only release a predetermined length of cable because the lateral protrusion extending from the toothless region 2703 on the spool gear 2701 abuts against the adjacent stop 3107 to prevent the bias of the respective bend from being completely let go. Upon removal of the depression force, a spring (not shown) pushes the ring gear 3101 back into engagement with the spool gear 2701 and the ratchet 2807.

[0168] Figures 31-33 Two spools 1701 are shown in the lifted position in the top diagram, each spool 1701 having a spool shaft 1101 but not being provided with a spool gear 2701 for engaging the ring gear 3101. These spools 1701 are used, for example, to control other components of the steerable arm 403, such as an end effector.

[0169] Figure 34bThe coupling 301 is shown how it engages with the coupling socket 901 in the motor box 805. The first stage of the process is shown in the top drawing and the second stage in the bottom drawing. The coupling socket has lugs 3401 lined up on the inner circumference of the cylindrical housing. The lugs 3401 push the ring gear 3101 to release the engagement between the ring gear 3101 and the spool gear 2601 before the spool shaft 1101 makes contact with the shaft receiver 1001.

[0170] Pre-tensioned stop or stopper 4

[0171] Figure 35 A further embodiment similar to the one shown includes a ring gear 3101 (i.e. drive gear 2601) to turn the spool gear 2701 from the circumference. A ratchet 2807 is provided to prevent accidental reversal of the rotation of the spool 1701. The above drawing shows two spools 1701, each provided with a spool gear. The drawing also shows two further spools 1701, but they are not provided with any spool gear 2701. Figures 31-34b

[0172] However, in contrast to the embodiment of Figure 32 there is only one set of drive teeth for engaging the spool gear and the ratchet. The drive teeth are provided as a continuous row of identical teeth 3501, lined up on the entire inner circumference of the ring.

[0173] With regard to turning the spool gear 2701, for example, turning the ring gear 3101 rotates the spool 1701, the operation of this embodiment is substantially the same as that of the embodiment of Figures 34a-34b Moreover, the ring gear 3101 can be depressed towards the coupling bottom 307 to disengage the spool gear 2701 and the ratchet 2807.

[0174] Figure 35 The ring gear 3101 shown in the embodiment of

[0175] However, upon release of the depression force on the ring gear 3101, any part of the continuous row of teeth 3501 can re-engage the spool gear 2701 and the ratchet. In contrast to this, Figures 31-34a the ring gear 3101 in the embodiment of

[0176] Other embodiments

[0177] ​In the foregoing embodiments, the stop function provided by the configuration of the various stops keeps a certain length of cable from being released by the spool, or allows a certain length of cable to be released. The convenience of this is that a spool can be provided with excess length of cable, and then the maximum releasable length is limited.

[0178] However, in a more basic embodiment, a precise length of cable for bending the manipulatable arm only to the required extent is provided between the spool and the rib at the distal end of the manipulatable arm. There is no need for a tab and stop mechanism to limit the length of cable that can be released. However, this embodiment introduces other problems. It is cumbersome to provide a precise length of cable, and is susceptible to assembly tolerance, compromising the required precision.

[0179] Thus, all embodiments embody a manipulatable arm that can be in a first position and a second position, the manipulatable arm being biased to the first position but being stopped from fully satisfying the bias to respond quickly when urged towards the second position by a force. The first position and the second position are determined by the length of cable that is paid out from the spool. The stop from fully satisfying the bias is provided by limiting the length of cable that can be paid out from the spool.

[0180] While the preferred embodiments of the application have been described in the foregoing specification, it is to be understood that many variations or modifications can be made therein by those skilled in the art, which fall within the scope of the invention as defined by the following claims.

[0181] For example, all the male and female configurations described in different parts of the embodiments can be reversed; instead of the male spool rod 1101 on each axle base 1601 fitting into the corresponding female rod receptacle 1001 in the coupler socket 901, a female rod receptacle 1001 of sufficient depth can be provided on each axle base 1601 to fit over a corresponding male protruding rod in the depth of the coupler socket 901.

[0182] The coupler does not have to have a housing, or the spool does not have to be in the form of a vertical, elongate, rotatable device as shown, but can be any form of cable paying out and cable winding up device.

[0183] In all embodiments, a salient feature is that the manipulatable arm can be in a first position and a second position, the manipulatable arm being biased to the first position but being stopped from fully satisfying the bias to respond quickly when urged towards the second position by a force.

Claims

1. A surgical instrument comprising: a steerable arm having a first resiliently flexible bend and a second resiliently flexible bend along said steerable arm; Each bend is connected to a respective first cable or second cable that straightens the bend when pulled; Each cable is connected to a respective first spool or second spool for winding and pulling the cable; Each spool has an axially aligned spool gear; a drive gear meshing with the spool gear; Rotating the drive gear can rotate the two spool gears so that the first spool and the second spool wind up the respective first and second cables to straighten the first and second curved portions; The drive gear is movable out of engagement with the spool gear, and The drive gear is capable of moving back to re-engage with the spool gear; in: The drive gear is configured to be moved by a poking rod in the coupler receptacle to disengage the spool gear when the surgical instrument is coupled to the coupler receptacle of the motor box for programmable control of the spool and cable.

2. The surgical instrument according to claim 1, wherein The spool gear of the first spool has missing gear teeth that limit the engagement range of the drive gear; Beyond the range, the drive gear cannot rotate and cannot cause the first spool gear to turn.

3. The surgical instrument according to claim 1, wherein The drive gear engages each of the spool gears through respective first and second pinions; The drive gear is movable to disengage from the pinion gear to disengage from the spool gear; and The drive gear can be moved back to re-engage with the pinion gear for re-engaging with the spool gear.

4. The surgical instrument according to claim 1, further comprising a ratchet gear configured to engage the drive gear, the engagement enabling the drive gear to rotate in one direction; The drive gear is movable to disengage from the ratchet gear and is movable back to reengage with the ratchet gear.

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