Patent Publication Number: US-2022211389-A1

Title: Orientation apparatus with feedback

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is the United States national phase entry of International Application No. PCT/EP2020/061292, filed Apr. 23, 2020, and claims the benefit of priority of German Application No. 10 2019 112 897.8, filed May 16, 2019. The contents of International Application No. PCT/EP2020/061292 and German Application No. 10 2019 112 897.8 are incorporated by reference herein in their entireties. 
     FIELD 
     The present invention relates to an apparatus or orientation aid for orienting a saw template or sawing block for removing an area of the tibial plateau during implantation of a knee joint prosthesis (hereinafter also referred to as tibial orientation aid). 
     BACKGROUND 
     When implanting, for example, an artificial knee joint, a surgeon has to remove, among other things, the defective head part of the tibial knee joint (tibial plateau, tibial head) with an oscillating bone saw. For this purpose, the surgeon uses an orientation device or orientation aid, which enables him to attach a saw template (also known as a sawing block) to the tibial head at the correct height and angle with respect to the tibia. 
     At the beginning of an implantation, the template is held to the tibial head by an extramedullary or intramedullary holding apparatus (which has or is the orientation aid). In other words, the holder of the template can be held to the tibial head “extramedullarily”, i.e. by a holder that is attached externally to the leg or tibia, or “intramedullarily”, i.e. by a bone nail or intramedullary nail or the like that is inserted into the tibia bone. Once the template is held to the tibia by the extramedullary or intramedullary holding apparatuses, fine adjustment of the relative position and orientation of the template is performed by a stylus (this is the orientation aid and may be part of the holding apparatus). The stylus determines the correct height of the template relative to the tibial head on the bone itself. Once the height is found, the template is screwed to the tibial head via screws and the holding apparatus including the stylus is removed again. 
     In order to position the artificial tibial component of the artificial joint on the original joint line, the physician has to probe the deepest defect site in the bone using the stylus and then has to set the thickness of the bone piece to be removed using a rotary knob and a scale. The value to be adjusted usually corresponds to the manufacturer-specific implant thickness, thus restoring the original joint line. From a medical point of view, however, it may be necessary to deviate from the original joint line and to move it in a targeted manner towards the body/in the distal direction or away from the body/in the proximal direction. 
     A knee prosthesis, knee endoprosthesis, artificial knee joint or knee joint prosthesis is an implanted prosthesis (endoprosthesis) that completely or partially replaces the knee joint. The knee prosthesis is mainly used in cases of severe wear and tear of the knee (knee joint arthrosis) and after injuries of the knee as a surgical therapy to restore pain-free mobility and, if necessary, also knee joint stability in cases of ligament instability. Partial or total endoprostheses may be used. 
     The shin bone (tibia) is one of the two bones of the lower leg, along with the calf bone (fibula). The shin bone is the stronger one of the two bones and is a typical tubular bone. The upper end, the head (caput tibiae), is the strongest part and carries two condyles (condylus medialis and condylus lateralis). In anatomy, the term condyle or ankle refers to the bony part of a joint, which is also called the articular process. In the knee joint, the upper end of the shin bone (tibia) and the lower end of the thigh bone (femur) each bear two condyles. On their upper surface, these have a cartilage-covered articular surface (facies articularis superior), which is separated into two parts by an elevation (eminentia intercondylaris). The elevation runs into two separate small knobs (tuberculum intercondylare mediale and tuberculum intercondylare laterale). It is bounded at the front (ventral) and back (dorsal) by two shallow pits (area intercondylaris anterior and area intercondylaris posterior). 
     The crucial ligaments and the retinacula of the menisci are attached here. The entire upper surface of the shin bone is called the tibial plateau and, together with the condyles of the thigh bone (femur), forms the knee joint. The articular surface (facies articularis fibularis) for the fibular head (caput fibulae) is found on the lateral circumference of the nearly vertical bone edge. 
     Tibial resection can be performed using either the extramedullary or intramedullary tibial resection technique. Each of the two techniques offers different setting possibilities for different anatomical conditions and ways of working. Extramedullary means ‘located outside the medulla’ and refers to the bone marrow (medulla ossium) or spinal cord (medulla spinalis). Intramedullary means ‘located within the medulla’ and refers to the bone marrow (medulla ossium) or the spinal cord (medulla spinalis). 
     Many physicians prepare the tibia in two steps in order to perform a check of the prepared bone in between. In a first step, only 2 mm are removed and, for example, in a second step, another 6 mm are removed, so that a total of 8 mm are removed. Some surgeons take the view to always operate in the most bone-sparing way possible and therefore remove as little bone as possible. In this case, a shift in the joint line is intentionally accepted, or compensated for by selecting appropriate implant thicknesses. 
     Knowledge of the exact thickness of the removed bone part is in any case relevant for the further course of the operation. For this purpose, an orientation apparatus or orientation aid for tibial resection guidance known in the prior art has or consists of a touch apparatus which has a generally helical adjustment element to which a feeler bar with a proximal probe tip is held. Furthermore, a generally helical wheel-shaped setting element is provided, which is in operative engagement with the adjustment element, i.e. the helix, so that the feeler bar can be moved longitudinally to the helix by manual actuation of the helical wheel. Finally, a scale carrier fixed/held on the feeler bar or on the helical wheel and extending longitudinally to the helix is provided with a scale mounted thereon, which indicates a current position of the probe tip along the helix with reference to a marking on the helical wheel or on the helix. If the orientation apparatus constructed in this way is coupled with the saw template, the relative distance between the saw template and the probe tip longitudinally to the helix can be adjusted/fine-tuned. 
     When determining the thickness of the removed bone part or the bone part to be removed, the setting and reading accuracy of the scale is decisive. In the prior art, however, these two factors are limited. In the prior art, the scale offers stepless graduation in millimeter steps via a thread (operative engagement between helix and helical wheel). During use, however, the surgeon&#39;s line of vision is not parallel to the scale but at an angle of approx. 45° from above to a central axis of the stylus/orientation aid. The center axis is the axis around which the helical wheel (setting wheel/rotary knob) of the stylus rotates. In the prior art, this may result in parallax errors (observation errors). In addition, the stepless settability offers room for interpretation as soon as a value is adjusted between two markings. In addition, the height may be adjusted by unintentionally touching the helical wheel/rotary knob, since there is no fixation. 
     SUMMARY 
     For this reason, it is necessary and therefore the object of the present invention to provide precise settability of the orientation apparatus and a good readability or detectability of the scale, in particular of the current position of the probe tip on the adjustment element. 
     The core idea of the present invention is essentially to provide/inform the surgeon with a tactile and/or acoustic signal during use, i.e. during setting/alignment of the orientation aid/touch apparatus according to the invention, from which the surgeon can draw conclusions about the position of the feeler/feeler tip longitudinally to the adjustment element (e.g. helix) or the distance between the feeler and the saw template, without the additional requirement of visually detecting the current scale value (with the eye). Constructively, this can be achieved in that the setting element (e.g. rotary knob/helical wheel) is formed with at least one protrusion and/or recess (first stop part), which can be brought into (latching/stop) contact with a pointer/snapper (second stop part) (fixed with respect to the setting movement of the setting element) in dependence on the (constantly repeating/traversing) setting position in the course of the setting movement of the setting element (e.g. rotation of the helical wheel), whereby the resistance (resistance force) generated by the setting element is changed (increased) against the manually applied setting actuation force. In this way, a surgeon can feel/sense the current relative position (e.g. angle of rotation) between the setting element (e.g. rotary knob) and the pointer/snapper at at least one point in the course of a setting movement of the setting element, and thus infer the position/adjustment travel of the feeler/feeler tip on the adjustment element. 
     If the first stop part is a cam-shaped projection, the pointer/snapper is elastically pushed (displaced) away from the cam-shaped projection when the setting element is actuated further. As soon as the pointer/snapper has reached the end of the cam-shaped projection when the setting element is correspondingly actuated further, the projection snaps back abruptly (if the projection is shaped correspondingly), which can be heard by a possibly loud clack. In this way, at least one, preferably two (continuously repeating/traversing) setting positions of the setting element can be sensed and/or heard. It should be noted that instead of or in addition to the pointer/snapper mentioned, the cam-shaped projection can also yield elastically. 
     According to a first aspect of the invention, the orientation apparatus/orientation aid for orienting a saw template has or is a touch apparatus having a feeler whose distance from the saw template is settable, for which the following is provided: 
     a movable, preferably rotatable setting means/setting element (e.g. helical wheel or gear wheel), 
     an adjustment means/adjustment element with a profiled indentation (e.g. helix or toothed rack), which is in (operative) engagement with the setting means and is also movable by movement/actuation of the setting means, 
     a scale carrier having a scale for measuring an adjustment path of the feeler preferably relative to the saw template in the longitudinal direction of the adjustment means, 
     at least one first stop means/stop part, which is formed on the setting means, 
     at least one second stop means/stop part which is formed on the scale carrier or serving as scale carrier and which is provided and adapted to act as resistance for the first stop means upon movement of the adjustment means by a certain amount of movement or movement distance, wherein 
     the second stop means or the first stop means resiliently deflects the respective other stop means upon further movement of the setting means beyond the determined movement amount or movement path. 
     In a preferred manner, the orientation apparatus according to the invention is a stylus/touch apparatus itself, which is provided and adapted to be coupled or is coupled to a saw template for positioning the saw template on a bone, preferably on a tibial head. The touch apparatus according to the invention may be positioned by an extramedullary or intramedullary holding apparatus or it is part of the holding apparatus. 
     In a preferred embodiment, the adjustment means moves relative to the setting means. The adjustment means is preferably a cylinder/rod with a thread, in particular an outer thread or helix or a surface with teeth or a cylinder with teeth—i.e. a toothed rack—or a cylinder with profiled indentations or the like. 
     The setting means is preferably a wheel, in particular a rotary knob or helical wheel in (operative) engagement with the adjustment means or a spring-loaded adjustment head or the like, possibly with a thread, preferably an inner thread, or a toothed wheel or a wheel with teeth or profiled indentations distributed evenly over the circumference or the like. Upon manual actuation, the setting means sets the feeler preferably longitudinally to a longitudinal axis of the adjustment means (helix/rotary knob combination) or perpendicular to an axis of rotation of the setting means (gear rack/gear combination). 
     According to a preferred embodiment, the feeler, preferably consisting of a feeler bar with a feeler tip arranged proximally thereto and preferably the scale carrier with a scale attached thereto or printed thereon, is firmly connected to the adjustment means or is formed or arranged in one piece so that it can be moved together with the adjustment means. According to an alternative embodiment, it is also possible to hold the feeler movably on the adjustment means and to move this via the setting means for movement of the adjustment means in the longitudinal direction of the adjustment means. The adjustment means thus moves according to a first alternative relative to the setting means or according to a second alternative together with the setting means, wherein the scale or scale carrier (which is preferably fixedly connected to the feeler bar) basically moves relative to the setting means. The scale may thus indicate a relative value or distance at which the feeler is located relative to the setting means. 
     In concrete terms, the adjustment means may be a hollow cylinder with a helix-like outer thread, which is mounted on an inner shaft that is connected/connectable to the saw template in a rotationally fixed but axially displaceable manner, and the setting means may be a helical wheel with an inner thread that is rotatably mounted (axially fixed) at the free end of the inner shaft, said inner thread being in operative/screw engagement with the outer thread of the hollow cylinder and displacing the hollow cylinder longitudinally to the (inner) axis upon (manual) rotary movement. In this case, the scale/the scale carrier, which is attached to the feeler firmly connected to the hollow cylinder or to the hollow cylinder itself, indicates the sliding path/distance of the hollow cylinder and thus of the feeler to the helical wheel and thus indirectly the distance between the template and the feeler. 
     The first stop means is preferably formed on the setting means. The first stop means preferably has the form of a groove, a notch or a recess or a projection, a tooth, a spring wire, a spring plate or a nose or the like. One or more of these first stop means may be formed on the setting means, preferably at a certain angular distance from each other, for example 180°. In the case of a wheel/rotating knob as setting means, the at least one stop means co-rotates with each rotation of the wheel. In the case of a spring-loaded adjusting head as setting means, a spring-loaded ball or the like in the head presses against the adjustment means. 
     The second stop means is formed on the scale or on the scale carrier, or the scale carrier forms the second stop means. The second stop means preferably has the form of a groove, a notch or a recess or a projection, a tooth, a spring wire, a spring plate or a nose or the like. The second stop means is provided and adapted to function as a, preferably latching, resistance to the first stop means. In other words, the second stop means is shaped to come into contact with the first stop means and thereby comes or enters into a latching/latchable engagement therewith. 
     The first and/or the second stop means are spring mounted or formed on a spring mounting or formed on a spring-elastic component or formed on a spring-elastic scale/scale carrier or forms a spring-elastic component or forms a spring elastic scale. In other words, when the setting element is moved, one (first) stop means comes into contact or engagement with the other (second) stop means. Here, the first and/or the second stop means may be spring-mounted. This means that one stop means presses against the spring-mounting or scale of the other stop means on which it is formed or presses the other stop means itself. One stop means pushes this spring-mounting or scale or the spring-loaded stop means (radially) away from the setting means and the stop means engage in each other or push against each other. When the setting means is moved further, one stop means disengages from the engagement of the other stop means in that the spring-mounting or scale or the other stop means itself is pressed away from the setting means by the one stop means. In this case, the mounting or scale or a stop means itself may be at least one spring element or spring-elastic or have several spring elements in series or parallel, so that when the setting means moves, a stop means always comes back into contact with the other stop means as it travels a predetermined distance. The first and second stop means may be made of any resilient material (e.g. spring steel, plastics or composite materials). The deflection of the stop means may not only be radial to an axis of rotation of the setting means, but also in the direction of rotation around the axis of rotation. 
     When one stop means engages in the other stop means, the orientation apparatus provides a haptic, tactile, acoustic (a clearly audible click), and/or visible feedback or signal to the user during adjustment. The invention can thus cause the adjustment means to move a predetermined distance when the setting means is rotated, and can cause a signal after this distance. At the same time, the latching function represents the safeguard against accidental setting. Thus, an acoustic and/or tactile feedback is provided for a simple and quick control of the adjusted value and securing of the adjusted value is provided without changing the size of the stylus (probing aid) significantly. Starting from an upper (0 mm) to a lower (12 mm) end stop, the user (e.g. physician or surgeon) can quickly and reliably determine the value to be set based on the number of ‘clicks’ (engagements), wherein the upper end is in the direction towards the setting means, and the lower end is in the direction towards the saw template or feeler holder. Reading errors can thus be avoided, an increase in safety in use can be ensured and a gain in time with optimum flexibility can be achieved. The field of view onto the bone is not additionally restricted with this solution. 
     Preferably, the orientation apparatus is configured such that the force required over the entire adjustment range of the scale, i.e. over the entire range in which one stop means engages with the other stop means, is approximately constant, but a stop resistance is generated which can be felt by the doctor/surgeon. This also results in a slim design of the scale. 
     All embodiments of the invention have the same core idea and may be combined with each other in an analogous manner. Thus, a first stop means of one embodiment may be combined with a stop means of another embodiment to provide acoustic, tactile, and/or visual feedback. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING FIGURES 
       The invention is explained in more detail below based on a preferred embodiment with reference to the accompanying drawings, of which: 
         FIG. 1  is an orientation apparatus/touch apparatus on an extramedullary framework/holding apparatus, 
         FIG. 2  is an oriented saw template on a tibial head, 
         FIG. 3  is an orientation apparatus/touch apparatus, 
         FIG. 4  is a first embodiment of an orientation apparatus/touch apparatus according to the invention in a rear view, 
         FIG. 5  is the first embodiment of the orientation apparatus according to the invention in a front view, 
         FIG. 6  is the first embodiment of the orientation apparatus according to the invention in a detailed view, 
         FIG. 7  is the first embodiment of the orientation apparatus according to the invention in a cut view in a first position, 
         FIG. 8  is the first embodiment of the orientation apparatus according to the invention in a cut view in a second position, 
         FIG. 9  is a second embodiment of an orientation apparatus/touch apparatus according to the invention, 
         FIG. 10  is a third embodiment of an orientation apparatus/touch apparatus according to the invention, 
         FIG. 11  is a fourth embodiment of an orientation apparatus/touch apparatus according to the invention, 
         FIG. 12  is a fifth embodiment of an orientation apparatus/touch apparatus according to the invention, 
         FIG. 13  is a sixth embodiment of an orientation apparatus/touch apparatus according to the invention, 
         FIG. 14  is a seventh embodiment of an orientation apparatus/touch apparatus according to the invention, 
         FIG. 15  is an eighth embodiment of an orientation apparatus/touch apparatus according to the invention, 
         FIG. 16  is a ninth embodiment of an orientation apparatus/touch apparatus according to the invention, 
         FIG. 17  is a tenth embodiment of an orientation apparatus/touch apparatus according to the invention, 
         FIG. 18  is an eleventh embodiment of an orientation apparatus/touch apparatus according to the invention with lateral load, 
         FIG. 19  is the eleventh embodiment of an orientation apparatus according to the invention with frontal load, 
         FIG. 20  is a twelfth embodiment of an orientation apparatus/touch apparatus according to the invention with frontal load, 
         FIG. 21  is a thirteenth embodiment of an orientation apparatus/touch apparatus according to the invention in front view, 
         FIG. 22  is the thirteenth embodiment of an orientation apparatus/touch apparatus according to the invention in a rear view, 
         FIG. 23  is a fourteenth embodiment of an orientation apparatus according to the invention, 
         FIG. 24  is a fifteenth embodiment of an orientation apparatus/touch apparatus according to the invention, 
         FIG. 25  is a sixteenth embodiment of an orientation apparatus/touch apparatus according to the invention, and 
         FIG. 26  is a seventeenth embodiment of an orientation apparatus/touch apparatus according to the invention. 
     
    
    
     DETAILED DESCRIPTION 
     In the following, embodiments of the present disclosure are described based on the corresponding figures. 
       FIG. 1  shows in principle a possible example of an extramedullary orientation apparatus/holding apparatus for tibial resection guidance, such as may be provided in the present subject matter of the invention. This comprises/has, for example, (not limited thereto) a telescope rod  16 , a foot restraint attached to the distal end of the telescope rod  16 , a saw template/sawing block  14  fixedly (non-detachably) attached to the proximal end of the telescope rod  16 , and a proximal orientation/touch apparatus (stylus)  1  preferably mounted at/on the saw template  14 . 
     The orientation/touch apparatus  1  is used on a tibial head. It usually has a feeler  8 , an adjustment means  6  for adjusting a distance between the feeler  8  and the saw template  14 , and a setting means  4  for actuating the adjustment means  6 . 
     The setting means  4 , for example in the form of a rotary knob, adjusts/actuates, by its manual rotation, the adjustment means  6 , for example in the form of a cylinder with outer thread, i.e. a helix. Preferably, the feeler  8  has a proximal feeler tip, which is incorporated/mounted via a feeler bar in/on a feeler holder  10  and is fixedly or (alternatively) movably connected via the latter, i.e. via the outer thread, to the adjustment means  6 . This means in both cases that when the setting means  4  is actuated, the feeler holder  10  and thus the feeler  8  moves in the direction towards or away from the setting means  4  corresponding to the actuation amount and the actuation direction. In addition, the feeler  8  is slidably mounted in the feeler holder  10 . A scale or scale carrier  12  indicates the distance, or the space, or a relative value of the feeler  8  relative to the setting means  4  in order to correctly position a saw template  14  on the tibial head  2 . In other words, the distance of the setting means  4  to the saw template  14  when mounted is known and fixed. Thus, the current distance of the feeler  8  to the saw template  14  can be displayed via the scale  12  located between the setting means  4  and the feeler  8 . 
       FIG. 2  shows the oriented saw template  14  on a tibial head  2 , wherein in this case the orientation/touch apparatus is not yet mounted on the saw template. 
       FIG. 3  shows another view of the orientation/touch apparatus  1  without a saw template. The rotary knob  4 , which is mounted on an inner retaining bolt/axis in a rotatable and axially fixed manner, moves the adjustment means  6 , i.e. the (hollow) cylinder with the outer thread (helix)  6 , the (hollow) cylinder being pushed on the inner retaining bolt in an axially displaceable manner, on which the feeler  8  is held/fixed via a feeler holder  10 , in the axial direction, whereby the feeler holder  10  is also moved in the axial direction longitudinally to the inner retaining bolt. The scale/scale carrier  12  is fixedly connected to the feeler holder or the hollow cylinder  6 . The rotary knob  4  thus pulls or pushes the hollow cylinder (with outer thread)  6  upwards (towards the proximal direction) towards the rotary knob  4  or pushes it downwards (towards the distal direction) away from the rotary knob  4 . In order to be able to better grip the rotary knob  4 , it has an axial portion with an outer knurl/riffle or outer grip surface, as shown in particular in  FIG. 3 . 
       FIG. 4  specifically shows a first embodiment of an orientation apparatus  101  according to the invention in a rear view, which is based on the orientation apparatus  1  described above in principle. The orientation apparatus  101  has the setting means  104  in the form of the rotary knob, which is axially fixed and rotatably mounted around the inner (rotationally fixed) retaining bolt and which, by rotation on the retaining bolts, adjusts the height of the adjustment means  106  in the form of the (hollow) cylinder with an outer thread (helix) longitudinally to the retaining bolt. The feeler  108  is firmly coupled/connected to the adjustment means  106  via the feeler holder  110 . In this case, the scale or scale carrier  112  is attached to the feeler holder  110 , projects in the direction of the setting means  104  and thus indicates the height/distance of the feeler  108  relative to the setting means  104  in order to position the saw template (not shown in  FIG. 4 ) correctly on a tibial head. The feeler  108  in the feeler holder  110  on the adjustment means  106  and the scale  112  on/at the feeler holder  110  thus move relative to the setting means  104  upon rotation/actuation of the setting means (rotary knob)  104 . In this respect, the structure of the invention is analogous to the orientation apparatus of the preceding figures. 
     The setting means  104  of the invention also has the axial portion with a roughened/riffled outer surface, which is followed, in accordance with the invention, distally (in the direction towards the feeler holder) by an axial portion with a comparatively smooth outer surface, which is provided and configured to be overlapped by the scale carrier  112  radially on the outside in the axial direction (see in particular  FIG. 4 ). The setting means  104  has, in particular in the axial portion with smooth outer surface, a first stop means  118 , for example in the form of a projection, which rotates together with the setting means (rotary knob)  104 . When the setting means  104  is rotated to a certain rotational position, the projection  118  contacts/abuts on the scale, or the scale carrier  112 , which is spring-elastic in the invention according to this embodiment. The projection  118  thus presses against the scale/scale carrier  112  during (further) rotation, which thus (radially) elastically moves away from the center axis/rotation axis of the setting means  104 , i.e. is displaced radially outwards, whereby (with displacement of the scale carrier  112  radially outwards) an increased resistance to rotation is generated. In the scale/scale carrier  112 , on the side facing the setting means  104  and thus also the projection  118 , a further stop means  120  is inserted or formed, for example in the form of a groove, which extends parallel to the axis of rotation. The projection  118  thus engages (abruptly) in the groove  120  when the setting means  104  is rotated further, and the scale/scale carrier  112  thus moves quickly or abruptly in the direction of the projection  118  (i.e. radially inwards) as a result of the spring pressure, whereby an acoustic, tactile, haptic and/or partly also visible feedback or signal (latching click) is given to the user. 
     For example, a single rotation of the setting means  104  causes the feeler  108  to move one or two millimeters relative to the setting means  104  longitudinally to the adjustment means  106 , wherein after each rotation (corresponding to each millimeter or two millimeters) the first stop means  118  engages the further (second) stop means  120 , thereby providing feedback to the user so that the user knows that the feeler  108  has been moved one or two millimeters by a corresponding rotation of the setting means  104 . 
     As already explained above, it is preferred to firmly connect the feeler holder  110  to the adjustment means  106 . In this case, the inner axis/retaining bolt is provided (see in particular  FIG. 8 ), onto which the adjustment means  106  in the form of the hollow cylinder with the outer thread is axially displaceable and preferably fixed against rotation. The setting means  104  in the form of the previously described rotary/helical wheel is mounted in a rotatable but axially fixed manner at the proximal free end/end portion of the (inner) axis and has an inner thread that is in screw engagement with the outer thread of the adjustment means  106 . As the setting means  104  is rotated about the (inner) axis, the adjustment means  106  in the form of the hollow cylinder is moved axially, longitudinally to the (inner) axis/retaining bolt, thus changing the distance between the feeler  108  and the setting means  104 . Alternatively, it would also be conceivable to connect the rotary knob firmly to the adjustment means (helix)  106  and to rotate the adjustment means  106  when the setting means  104  is actuated. In this case, the feeler holder  110  is in screw engagement with the outer thread of the adjustment means  106  and is axially displaced when the adjustment means is rotated accordingly. As an anti-rotation device for the feeler holder  110 , the feeler  108  could, for example, be held manually or could be guided longitudinally in a stationary rail (not shown) arranged parallel to the adjustment means  106 . 
       FIG. 5  shows a front view of the first embodiment of the orientation apparatus  101  according to the invention. The structure is analogous to  FIG. 4 . The setting means  104  moves the feeler holder  110  via the adjustment means/helix  106  (which is fixedly connected to the feeler holder  110  and/or the scale carrier  112 ) by rotation around the (inner) retaining bolt, whereby the feeler  108  in the feeler holder  110  is also moved. The scale  112  is preferably attached to the feeler holder  110  and is thus firmly connected to the feeler holder  110 . The first stop means  118  on the setting means  104  comes into contact with the scale/scale carrier  112  and bends it outwards, i.e. away from the axis of rotation. Since the scale/scale carrier  112  is attached at its lower (distal) end to the feeler holder  110 , the force required to bend the scale  112  outwards is lower at the top (proximally) than at the bottom (distally) where the scale is attached (due to leverage). This means that less force is required at the top (proximally) to deflect the scale  112  than further down (distally). Preferably, the scale/scale carrier  112  is made of spring steel or another metal with a high spring stiffness or spring elasticity. However, the scale/scale carrier  112  according to the invention is preferably divided into two serial spring elements  124  and  126  which divide the force in series (see  FIG. 7  and  FIG. 8 ). The scale/scale carrier  112  preferably has the shape of a platelet/rectangle, which is firmly connected to the feeler holder  110  at one end. An incision is made in the scale/scale carrier  112  in the form of an inverted U, whereby the first spring element  124  is formed by the outer scale frame created thereby and the second spring element  126  is formed by the inner spring tongue created thereby, wherein the spring tongue is fixed to the scale frame at the axially free end (upper/proximal end) of the scale frame. Due to this series arrangement of the spring elements  124  and  126 , the force for pushing away the scale carrier via the first stop at the lower (distal) end of the scale/scale carrier is essentially the same as the force for pushing away the scale carrier via the first stop at the upper (proximal) end of the scale/scale carrier (lever path to the respective pivot point ‘down/up’ remains essentially the same). 
       FIG. 6  shows a detailed view of a first embodiment of an orientation apparatus  101  according to the invention. The adjustment means  106  is fixedly connected to the scale  112  via the feeler holder  110 . In other words, the scale  112  is a spring  122  with a first bending spring element  124  and a second bending spring element  126  connected in series with the first spring element, wherein the pivot points of the two bending springs are positioned at the opposite ends of the spring. The U-shaped recess in the scale  112  extends the lever of the entire spring  122 , wherein the first spring element  124  and the second spring element  126  are in series. Through the recess, the first spring element  124  is formed by two side elements laterally enclosing the U-shaped recess. In order to obtain the desired latching effect and an acoustic feedback (a clearly audible click), the scale  112  is constructed resiliently in the upper and lower area, namely in the upper area by the (outer, frame-shaped) spring element  124 , in the lower area by the (inner, tongue-shaped) spring element  126 . The tongue-shaped spring element  126  thus avoids a (linearly) increasing force when the rotary knob/setting means  104  is turned downwards, or when the setting means  104  pulls the adjustment means  106  upwards. The second (tongue-shaped) spring element  126  has the fixed point at the upper/proximal end of the scale  112 , wherein upper refers to the non-fixed side of the scale  112  at the feeler holder  110 , and the first (frame-shaped) spring element  124  has the fixed point at the lower/distal side to the feeler holder  110 . Accordingly, the frame  124  works as a spring in the upper area. The further the adjustment means  106  is moved towards the setting means  104 , the more the inner tongue or the spring element  126  takes over the spring function. The acoustic feedback occurs when the first stop means  118  engages the second stop means  120 , which is located in one of the two spring elements  124  or  126 , e.g. per revolution at 2 mm thread pitch. 
       FIG. 7  shows the first embodiment of the orientation apparatus  101  according to the invention in a cut view in a first position. The first position shows the setting means  104  which embraces the adjustment means  106  and is able to move the adjustment means  106  by rotation of the setting means  104 . The setting means  104  has two projections  118 , wherein one of the projections presses against the first spring element  124 , which is attached at one end to the feeler holder  110 . The projection  118  forces the spring element away from the setting means  104 , causing the spring element to deflect radially outwards. 
       FIG. 8  shows the first embodiment of the orientation apparatus  101  according to the invention in a cut view in a second position. In the second position, the setting means  104  has pulled the adjustment means  106  towards it, whereby the feeler holder  110  with the scale thereon is also closer to the setting means  104 . The projection  118  is now close to the feeler holder  110 . The U-shaped recess now pushes the second spring element  126  outwards and away from the setting means  106 . 
       FIG. 9  shows a second embodiment of an orientation apparatus according to the invention. In this embodiment, the setting means  204  is rotatably mounted on the adjustment means  206  and moves the latter, in a manner as described above. In this embodiment, the first stop means  218  on the setting means  206  is a groove extending externally of the setting means  204  parallel to the axis of rotation of the setting means  204 . At the scale  212 , which is a spring  222  analogous to the first embodiment and has a spring elasticity, the second stop means  220  is in the form of a projection. 
       FIG. 10  shows a third embodiment of an orientation apparatus according to the invention. A setting means  304  is configured in the form of a gear that engages the adjustment means  306  in the form of a surface with teeth. A scale is formed on the side of the adjustment means  306 . A spring  322  has a projection on a side facing the setting means  304  (not shown) that engages the teeth of the setting means  304  and thus provides acoustic and haptic feedback to the user when the user rotates the setting means  304 . 
       FIG. 11  shows a fourth embodiment of an orientation apparatus according to the invention. The setting means  404  has a spring-preloaded ball (not shown) in an inner side as a first stop means  418 . The adjustment means  406  has indentations that serve as a second stop means  420 . A scale  412  is applied to the adjustment means at the projections between the indentations. 
       FIG. 12  shows a fifth embodiment of an orientation apparatus according to the invention. A scale  512  is formed with a T-shaped cross-section. In other words, a rectangular surface at its long central axis has another rectangular surface perpendicular thereto. This second surface or flag is a spring-elastic stop means  520  in the form of a spring plate which engages or can latch into a second stop means  518  (e.g. a groove) on a setting means (not shown). 
       FIG. 13  shows a sixth embodiment of an orientation apparatus according to the invention. A scale  612  is formed with a wire as a stop means  520 . In other words, a rectangular surface has on its long central axis an angled, spring-elastic wire/spring wire thereto, which is connected at two ends to the scale  612 . This wire is thus a spring-elastic stop means  620  which engages or can latch into a second stop means (e.g. a groove) on a setting means (not shown). 
       FIG. 14  shows a seventh embodiment of an orientation apparatus according to the invention. The scale or spring  722  is analogous to the first embodiment with the exception that the scale has a third spring element  728  in series with a first spring element  724  and a second spring element  726 . The third spring element  726  is again in the form of a U, that is offset by exactly 180° from the first U, and has its fixed point again at the upper end. This means that the force required is even more linear than in the first embodiment. 
       FIG. 15  shows an eighth embodiment of an orientation apparatus according to the invention. Here, the second stop means  820  is similar to the first embodiment, with the difference that the second spring element  826  is mounted in the first spring element  824  in a U-shape rotated at an angle of 90° , or has the fixed point at an angle of 90° to the lower end. 
       FIG. 16  shows a ninth embodiment of an orientation apparatus according to the invention. In this embodiment, the second stop means  920  is provided with a plurality of second spring elements  926 , which are formed as in the eighth embodiment. The plurality of second spring elements  926  are arranged in parallel from bottom to top and are framed by the first spring element  924 . 
       FIG. 17  shows a tenth embodiment of an orientation apparatus according to the invention. In this embodiment, the second stop means  1020  has at least two incisions that run parallel to the lower end of the stop means  1020  where it is attached to the feeler holder (not shown). Thus, the stop means  1020 , which also forms the scale, is radially deflected at different locations. 
       FIG. 18  shows an eleventh embodiment of an orientation apparatus according to the invention with lateral load. The stop means  1120  comprises a spring wire in the form of a hook/U attached at one end to the feeler holder. A first spring element  1124  has the fixed point at the feeler holder, a second spring element  1126  has the fixed point at the upper end of the first spring element  1124 . As shown by the arrows, the stop means  1120  can be deflected in the direction of rotation of a rotatable setting means (not shown). 
       FIG. 19  shows the eleventh embodiment of an orientation apparatus according to the invention with frontal load. In addition to the rotational deflection of the first spring element  124  and/or second spring element  126  shown in  FIG. 18 , the second stop means  1120  may also undergo a radial orientation as shown by the arrows in  FIG. 19 . 
       FIG. 20  shows a twelfth embodiment of an orientation apparatus according to the invention with frontal load. The structure of the twelfth embodiment is analogous to the eleventh embodiment, except that the stop means  1220  does not consist of a single U-shaped wire, but that the first spring element  1224 , in the form of a straight spring wire, is connected at its upper end by a plate or the like to the second spring element  1226 , which is formed parallel to the first spring element  1224  in the form of a straight spring wire. 
       FIG. 21  shows a thirteenth embodiment of an orientation apparatus according to the invention in front view. In this embodiment, the scale has a rectangular cut  1330 . The rectangular cut  1330  leads from the vicinity of the upper end of the scale to the vicinity of the lower end of the scale. The scale is divided by the rectangular cut  1330  into a first spring element  1324  and a second spring element  1326 . This embodiment allows for audible, visual, and tactile feedback according to the principle of a barrel organ. When one rectangular surface is deflected by a projection of a setting means (not shown), the other spring element springs back and vice versa. 
       FIG. 22  shows the thirteenth embodiment of an orientation apparatus according to the invention in a rear view. At the rear of the scale, a groove  1320  is provided as a second stop means extending from the upper end to the lower end and passing through the first spring element  1324  and the second spring element  1326 . The groove also extends through the rectangular cut. 
       FIG. 23  shows a fourteenth embodiment of an orientation apparatus according to the invention. This embodiment is analogous to the thirteenth embodiment with the only difference that this embodiment does not have a groove on the rear side and serves as a second stop means  1420  without a groove. Likewise, in this embodiment, a rectangular cut  1430  separates the stop means into a first spring element  1424  and a second spring element  1426  from top to bottom. 
       FIG. 24  shows a fifteenth embodiment of an orientation apparatus according to the invention. This embodiment is analogous to the thirteenth or fourteenth embodiment with the difference that a cut  1530  is not rectangular but has the shape of a wave and a second stop means  1520  is divided into a first spring element  1524  and a second spring element  1526 . 
       FIG. 25  shows a sixteenth embodiment of an orientation apparatus according to the invention. This embodiment is applicable to any of the preceding embodiments having a further spring element/second spring element separated from the first spring element by a U-shaped cut in the scale. Here, a first stop means  1618  is brought to a second stop means  1620  by rotation of a setting means. The second stop means  1620  moves radially away from an axis of rotation of the rotatable setting means. The first stop means  1618  abuts a frame of the second stop means  1620 . The second stop means  1620  is separated from the rest of the scale by a cut, preferably a U-shaped cut, so that it can be deflected on one side. 
       FIG. 26  shows a seventeenth embodiment of an orientation apparatus according to the invention. This embodiment is applicable to any of the preceding embodiments having a further spring element/second spring element separated from the first spring element by a U-shaped cut in the scale. In this embodiment, the second stop means  1720  has a rounded surface around a groove so that the first stop means  1718  comes into more gentle contact therewith. 
     In summary, the present invention relates to a touch/orientation apparatus comprising, for orienting a saw template, a setting means, an adjustment means having a profiled indentation and a feeler movable relative to the setting means, a scale for measuring a height of the setting means relative to the adjustment means, at least one first stop means formed on the setting means, at least one second stop means formed on the scale or serving as a scale and provided and adapted to act as a resistance for the first stop means, wherein the second stop means and/or the first stop means resiliently deflects the respective other stop means.