CN102048581B

CN102048581B - Medical instrument for double-cross-surface directional minimally invasive intracerebral foreign body removing operation

Info

Publication number: CN102048581B
Application number: CN2009102197545A
Authority: CN
Inventors: 孙树杰
Original assignee: SEVEN STAR INTERNATIONAL TRADE CO Ltd
Current assignee: Shanghai Cushing Medical Technology Co., Ltd.
Priority date: 2009-11-10
Filing date: 2009-11-10
Publication date: 2013-06-05
Anticipated expiration: 2029-11-10
Also published as: CN102048581A

Abstract

The invention relates to a simple, convenient, precise and fast positioning medical instrument for a double-cross-surface directional minimally invasive intracerebral foreign body removing operation. The medical instrument provided by the invention comprises a positioning rule with multiple surfaces of strip holes, two flat plates which are mutually vertical are connected through a transition plate to form a three-surface plate, and longitudinal strip holes or transverse strip holes which are arranged and size scales are formed on the plate surfaces of the three-surface plate; and the medical instrument further comprises a positioning hole-opening drill and a lock hole guide device, and each one of the two components comprises at least two intersectional radial plates or intersectional lines and at least two intersectional planar light lasers which are collinear with the axial line of a drill bit. The positioning rule with the multiple surfaces of the strip holes is used for drawing projection drawing lines of a foreign body in all directions on the surface of the head, further drawing an intersection point of the lines to serve as a hole-opening point, and keeping the intersectional radial plates or the planar light protection lines of the positioning hole-opening drill and the lock hole guide device covering the intersectional lines, thereby being simple, easy and fast to ensure the hole-opening direction and further ensuring that the direction of inserting a guide tube points to the foreign body.

Description

The directed Wicresoft of double cross face intracranial foreign body is removed the Medical Instruments of art

Technical field: the present invention is a kind of after cranium computed tomography brain scan three-dimensional localization, determining that head aperture position and Wicresoft's perforate go deep into the Medical Instruments that intracranial is removed foreign body, is mainly to demarcate to determine position of opening, carry out directed perforate and visit the utensil of taking foreign body after intracranial is determined the foreign body position.

Background technology: Wicresoft's foreign body (as hematoma) paracentesis have been carried out a lot of years at home, but the impact of operation receiveing person's experience and technology, and the paracentetic curative effect of foreign body (as hematoma) is difficult to be subject to objective appraisal.Brain foreign body (as hematoma) paracentesis in the past are by patient's Cranial Computed Tomography or the three-dimensional data of CT sheet, determine foreign body (as hematoma) center target spot and enter the cranium path, although can determine foreign body (as hematoma) center target spot by measuring patient head CT or CT, but because head is a globoid, be difficult to the puncture of vertical target point, therefore the angle that enters cranium easily produces skew, has reduced the accuracy of foreign body (as hematoma) puncture.If adopt gauge to position, and orientate body as with this instrument, carry out directed perforate, although degree of accuracy is higher in theory, but want indeformable just must do more abundant and heavy of instrument stabilizer, counterpart's head is fixedly more difficult again, be fixed on head human body surface because the human body is software, easily to produce relative position to change, particularly at patient's stupor or agonizing state, add heavy huge instrument at head again, hinder and carry out CT examination, again dismounting repeatedly.Each dismounting is just adjusted the location again, is difficult to keep stablizing and not play or the swing of relative head, the more inconvenient treatment of carrying out at short notice emergency treatment head orientation surgical patient.Consult a large amount of foreign body (as hematoma) paracentesis document, the patient does not all describe how to control its direction when the paracentetic process puncture needle of foreign body (as hematoma) enters in detail.In the puncture for treating process, be unavoidable the generation to the skew of skull Wicresoft super hole cutter.

Summary of the invention:

the present invention solves in prior art exactly, positioning and guiding to head Wicresoft's perforate location and perforate process is complicated, the apparatus measures cost is high, the location is fixing more time-consuming, also easily give the misery of patient's pinch, the problem that misoperation perforate steering error is larger, provide a cover easy, accurately, location and guiding are controlled fast, guarantee the double cross face directed Wicresoft intracranial foreign body removing art Medical Instruments used that the puncture error reduces greatly, a kind of positioning rule of locating the multiaspect cylindrical void for foreign body location and perforate in the taking-up head particularly is provided, a kind of locating open hole drill for taking out foreign body in head is provided, a kind of lockhole guiding device for taking out foreign body in head is provided.

Of the present invention a kind of for taking out foreign body location and perforate location multiaspect cylindrical void positioning rule in head, two flat boards connected vertically are mutually arranged, flat board has cylindrical void, it is characterized in that: connect and compose three panels by a rebound between two flat boards, the plate of three panels has vertical cylindrical void or horizontal cylindrical void, and three panel vertical and horizontal are with size scale.Three panels that are connected to form by transition (inclined-plane) plate like this, can properlyer be placed in the transition face between the side of head and front (or back) and side, front (or back), perhaps side (or back or front) and top and side (or back or front), the transition face between top.Preferably three panels flat board is parallel with the corresponding flat board of another piece three panels, and the dull and stereotyped relative sliding of another in these two three panels connects, and forms the integrated positioning chi.It is relatively dull and stereotyped that integrated positioning chi relative sliding connects, can be the equidirectional cylindrical void that has, after combination, cylindrical void be overlapped, can be also mutually vertically to have cylindrical void, after combination, cylindrical void is interlaced overlapping, draws continuously in staggered space as required point to be linked to be line after a little taking away the integrated positioning chi again; Can also be that one flat plate has cylindrical void, another relatively flat board be empty frame, the flat board that relative sliding connects does not block cylindrical void, the dull and stereotyped random position of the relative sliding of being more convenient for so more can increase the accuracy of setting-out.Utilize anatomical knowledge to find out fast orbitomeatal line, median line, and draw the orbitomeatal line that is reflected in head surface, median line.A dull and stereotyped A face of three panels is or/and a cylindrical void of C face is parallel with orbitomeatal line, the cylindrical void of another dull and stereotyped B face is parallel with median line, utilizes cylindrical void on each face can draw fast a plurality of sagittal planies in the meld line (sagittal line) of head surface and a plurality of horizontal plane meld line (horizontal line) at head surface.Keeping under a flat board (B face) cylindrical void constant condition parallel with sagittal plane at last, change angle 90 degree of three panels, make another dull and stereotyped A face or/and the C face) vertical with orbitomeatal line and horizontal line (horizontal plane is horizontal line in the head surface meld line), dull and stereotyped A face be or/and the cylindrical void of C face can draw coronalplane in the meld line of head surface, i.e. crown line.According to above-mentioned scratching process, utilize patient's CT or MRI view data, find horizontal bedding, sagittal plane, the coronalplane at the place, center of foreign body (as hematoma) on image.Can pass through the sagittal plane at foreign body (as hematoma) place, center apart from the slice thickness between the sagittal plane at median line place, find foreign body (as hematoma) center in the projection of head surface, namely foreign body (as hematoma) place, center sagittal plane is at head surface meld line (sagittal line).Can pass through the horizontal plane at foreign body (as hematoma) place, center apart from the slice thickness between the horizontal plane at orbitomeatal line place, find foreign body (as hematoma) center in the projection of head surface level, namely the horizontal plane at foreign body (as hematoma) place, center is at head surface meld line (horizontal line).The coronalplane that can pass through foreign body (as hematoma) place, center is apart from the slice thickness between the coronalplane of center (or apart from head front end distance or apart from head rear end distance), find foreign body (as hematoma) center at the projection line of head surface, namely foreign body (as hematoma) place, center coronalplane is at head surface meld line (crown line).Use like this setting-out method to identify the projection position on patient's head surface, and take this setting-out as criterion.And then with each face of foreign body (as hematoma) place, center in the cross point of head surface projection line (meld line) as tapping point, and to form two, this cross point reticule two meld line of cross point (form) as benchmark, determine the direction that utensil is got in the direction of perforate and insertion conduit and spy.The present invention just can determine tapping point and perforate direction by accurate quick like this, accurately conveniently takes out foreign body after perforate, and is easy to operate.The present invention finds out foreign body (as hematoma) center to be used as judging directional reference at the projection line of head surface, and the directional reference that makes this surgical aperture and take out foreign body has more objectivity.Become the combination positioning rules with two three panel-shaped, namely form five noodles holes positioning rules of the present invention, be more convenient for locating fast setting-out at head surface, and can locate the setting-out that marks simultaneously three, operate more simple and efficient.

The present invention is used for taking out foreign body locating open hole drill in head, organism, be arranged in body driving mechanism with the coaxial drill bit that is connected of driving mechanism output shaft, it is characterized in that: body is with at least two radial plate, at least two radial plate extended surface intersecting lenses and drill axis conllinear.Body forms the radial plate of two phase cross surfaces with the radial plate of at least two intersections; Can be also three radial plate, wherein two on same plane, and another piece and front two are intersected, and form the radial plate of two phase cross surfaces; Can also be four radial plate, wherein each two two faces intersect at same, intersecting lens is with collinear in drill axis.In these three kinds of situations and other multiple situations, in two intersecting planes, radial plate and the body that can also be a phase cross surface are fixed, the radial plate of another phase cross surface and body interference fits are rotationally connected, rotate relative to body, change the angle relative with its radial plate that intersects, come the angle of the intersection of corresponding head surface projection line.During perforate, with each face of foreign body (as hematoma) place, center in the cross point of head surface projection line (meld line) as tapping point.The perforate process keeps radial plate overlapping with the reticule in cross point in the projection of head surface, just can guarantee to the perforate of foreign body (as hematoma) center position.Be used as judging directional reference to find out foreign body (as hematoma) center at the projection line of head surface like this, this surgical aperture directional reference is more just easily held, operation is simple, and accuracy is more objective and directly perceived.

Another kind of the present invention is used for taking out foreign body locating open hole drill in head, organism, be arranged in body driving mechanism with the coaxial drill bit that is connected of driving mechanism output shaft, it is characterized in that: body is with the laser instrument of launching at least two intersecting plane light that intersect at drill axis.Equally, the perforate process is opened laser instrument, makes the irradiation of crossing planar light overlapping with the reticule maintenance of tapping point at the crosslights of head surface, just can accurately keep the direction of perforate towards the position at foreign body center, operates more simplely, and accuracy is higher.

The present invention is a kind of for taking out foreign body lockhole guiding device in head, have conduit, with conduit tube core movingly, it is characterized in that: tube core or conduit outer end form the radial plate of two phase cross surfaces with at least two radial plate.In the radial plate that forms two phase cross surfaces, preferably the radial plate of a phase cross surface and body are fixed, the radial plate of another phase cross surface and body interference fits are rotationally connected, be more convenient for adjusting the at any time angle of the mutual intersection radial plate in two phase cross surfaces is so that consistent with the reticule angle around perforate.At least two radial plate extensions are practised physiognomy and are met at drill axis.Tube core inserts conduit, together stretch into head by the perforate of head with conduit, as long as keep radial plate overlapping at projection and the reticule around perforate of head surface, just can guarantee to stretch into to foreign body (as hematoma) center position, just can keep after fixing conduit towards or reach foreign body (as hematoma) center, controlling party tropism is very simple fast.

Another kind of the present invention is used for taking out foreign body lockhole guiding device in head, have conduit, with conduit in tube core movingly, it is characterized in that: tube core or conduit outer end are with the laser instrument of at least two intersecting plane light launching intersecting lens and drill axis conllinear.Using thisly when taking out in head the foreign body lockhole guiding device, opening laser instrument, tube core together stretches into head by the perforate of head with conduit in conduit.Insertion process and fixation procedure, as long as the crossing plane light that keeps laser instrument to send is overlapping at projection reticule and the reticule (meld line) around perforate of head surface, just can guarantee to stretch into to foreign body (as hematoma) center position, just can keep after fixing conduit towards or reach foreign body (as hematoma) center, controlling party tropism is very simple.

Description of drawings: accompanying drawing has represented that a cover of the present invention is used for taking out the apparatus structure schematic diagram of foreign body in head.Wherein, Fig. 1, Fig. 2 locate the perspective view of multiaspect cylindrical void positioning rule both direction for foreign body location and perforate in the taking-up head; Fig. 3 is that this Fig. 4 is its side-looking structural representation for taking out foreign body location and perforate location multiaspect cylindrical void positioning rule plan structure schematic diagram in head, and Fig. 5 is TV structure schematic diagram thereafter, and Fig. 6 is its main TV structure schematic diagram; Fig. 7, Fig. 8 are for being used for taking out the perspective view of the both direction that in head, foreign body locating holes manual and electric dual-purpose bores; Fig. 9 is this main schematic diagram for taking out the reflection internal structure that in head, foreign body locating holes manual and electric dual-purpose bores, and Figure 10 is that it is from the structural representation of drill bit direction.Figure 11 is that foreign body position fixing process three-dimensional coordinate and three faces and head surface are rule in taking out head concerns schematic diagram, wherein three intersection points of the crown line C. of A. sagittal line B. horizontal line D. (foreign body center).Figure 12 is for taking out foreign body locating holes electric drill front view in head; Figure 13 is for the left view that takes out foreign body locating holes electric drill in head.Figure 14 is for the main sectional structure schematic diagram that takes out foreign body locating holes hand drill in head; Figure 15 is for the left TV structure schematic diagram that takes out foreign body locating holes hand drill in head.Example below in conjunction with accompanying drawing further illustrates.

The specific embodiment:

Embodiment 1, a kind of of the present invention for take out hematoma location and perforate location multiaspect cylindrical void positioning rule in head (referring to Fig. 1,2,3,4,5,6), two flat boards 1 connected vertically, 2 or 4,5 are mutually arranged, flat board has cylindrical void.In two flat boards, a flat board 2 vertically has cylindrical void, and another flat board 3 laterally has cylindrical void, connects and composes three panels by a

rebound

1 or 6 between two

flat boards

2,3 or 4,5.Three panel vertical and horizontal are with

size scale

10,14, have consisted of the three noodles holes positioning rules that the present invention is used for taking out foreign body location and perforate location in head.First according to head surface sign location, as horizontal plane, mesion as sagittal plane, utilizes localizer to determine the coronalplane of cranium brain, and draw the head stereoscopic drop shadow curve that represents above-mentioned three dimensions on patient's scalp before and after the head with the aspect of CT scan.As shown in the figure, make up with the three noodles holes positioning rules of the present invention of two, consisted of five noodles holes positioning rules of the present invention, be called for short five chis.The flat board of five chis or rebound are called for short face, and in the flat board and rebound of five chis, 2,4 parallel, and 3,5 and 2,4 panels are vertical, and 2,4 faces have several and parallel plane cylindrical void, and

face

1,6 also has the cylindrical void that is parallel to each other.The bar number of perforations of each face of five chis is different, and cylindrical void wide footpath, interval, carpenters square back gauge all equate, the centrage of middle cylindrical void is divided its plane, place equally up and down, is equipped with labelling and

size scale line

8,10,11 on every block of plate.3,5 can also be an insertion type plane, 3,5 protruding transition of two three chis is embedded mutually the other side's chute, forms two

faces

3,5 relative slidings connect, and adjusts to be suitable for different patient's head width.Can also be in 3,5 of two three chis, the

chute

15,19 that face 5 has, face 3 correspondence positions have

screw

18,21, passing chute by

screw

16,20 is connected with screw, form two

faces

3,5 relative sliding syndetons, can adjust at any time and be suitable for different patient's head width, and tighten screw and form fixing.2,4 faces of both sides be close to be attached to head both sides, can according to the size of different patient's heads fast, adjust screw and relative two

faces

3,5 slide, adjust to accurately the position that is fit to patient's head width, 2,4 faces that guarantee both sides are close to and are attached to head both sides.And the cylindrical void on 2 be along three panels vertically, mutually vertical with the cylindrical void of 3,4, the cylindrical void of 1,6 be vertical along three panels, 5 be empty frame and 3 overlapping.Utilize side's body intracranial hematoma localization method of the present invention: head is regarded as a cube, utilize anatomical knowledge to find out fast orbitomeatal line, median line, one cylindrical void of 2 of five chis is parallel with orbitomeatal line, the cylindrical void of 3 is parallel with median line, utilizes remaining cylindrical void on chi can draw fast a plurality of sagittal planies and horizontal plane in the meld line of head surface.Under 2,4 of maintenances and cylindrical void constant condition parallel with median sagittal plane, change angle 90 degree of five chis at last, make the cylindrical void of 2 vertical with horizontal plane, can draw coronalplane in the meld line of head surface.Utilize patient's CT or MRI view data, size and the cylindrical void of five chis of recycling, correspondence draws hematoma place sagittal plane, coronalplane, horizontal plane in the meld line of head surface.First find the center aspect of hematoma on CT or MRI image, can pass through the thickness data of the aspect of hematoma central core identity distance orbitomeatal line, draw apart from the setting-out of the parallel cylindrical void of orbitomeatal line same thickness distance at head surface with five chis again, drawn exactly the center aspect of hematoma in the meld line of head surface, also just find the hematoma center in the projection of head surface horizontal direction, be called for short horizontal line.Equally, utilize patient's CT or the locator data of the MRI image provides intracranial hematoma center target spot, can be by the place sagittal plane mutual gauge of place, hematoma center sagittal plane apart from median line, draw place, the center sagittal plane of hematoma in the meld line of head surface, also just find the hematoma center in the projection of head surface sagittal line direction, be called for short sagittal line; Can draw place, the center coronalplane of hematoma in the meld line of head surface by place, hematoma center coronalplane size before and after the head, also just find the hematoma center in the projection of the crown line direction of head surface, be called for short crown line.The cross point of these meld line is exactly to stretch into utensil after the point of perforate and perforate to carry out hematoma drain entrance, can be accurately with the hematoma drain out.As determine in the projection perforate of head horizontal direction with to the pathway at hematoma center, the place, cross point of meld line (crown line) that is meld line (horizontal line) and the crown line direction projection of the projection in the horizontal direction of hematoma center is the perforate position, and this is namely take place, hematoma center coronalplane, horizontal plane intersecting lens as pathway.By this perforate position, enter intracranial along this pathway, can accurately find the hematoma center when reaching the sagittal plane at place, hematoma center, then by the perforate accurately of locating open hole drill, and along this hole and pathway, hematoma is taken out.

Embodiment 2, a kind of of the present invention for taking out foreign body locating holes manual and electric dual-purpose brill in head, organism, be arranged in body driving mechanism with the coaxial drill bit that is connected of driving mechanism output shaft, body is with two groups of planar light laser instrument (also claiming generating laser) in addition, two groups of laser instrument are launched two planar light and are mutually intersected, intersect at drill axis, i.e. intersecting lens and drill axis conllinear.As shown in Fig. 7,8,9,10, in figure, 6. drill bit locker, 21. drill bit, 9,10,16,17. travelling gears .2,3,4,5 planar light laser instrument, 13. power transmission shaft, 14. handles and inner battery, 19. connecting rods, 20. joystick rocking handle, 11. starting switch, 12. sealing waterproof cases, 15. motor, 7. laser beam adjustable ring, 8. planar light laser instrument connecting ring.It is motionless that one group of planar

light laser instrument

2,4 is fixed on the connecting ring of body, sends same plane light, and planar light and motor axis, drill axis 1 are coplanar.Another group is that adjustable planar

light laser instrument

3,5 is arranged on laser beam adjustable ring 7, can be along with laser beam adjustable ring 7 rotates around body and axis, also send same plane light, planar light and motor axis, drill axis are coplanar, crossing with fixing planar light simultaneously, intersecting lens and axis are the same line, i.e. conllinear.Adjustable planar light can be according to the angle of head surface reticule, adjust the angle that intersects with fixing planar light, reach consistent, and in the planar light that intersects when the head surface projection line overlaps with the surface crosswise line, just just in time make the axis of drill bit pass the hematoma center, keep the accurate direction of boring.Form two and intersect planar light, also quite simulate the plane of passing the hematoma center on the CT sheet.Keeping at any time the laser beam of crossing plane light to impinge upon head surface according to the head surface setting-out like this is crosslight, as long as keep crosslight to overlap with the setting-out of head surface, the joining of light just in time with drill bit shaft on same straight line, the orientation of its axis of drill bit is also passed the hematoma center, just can accurately determine the direction of puncture.

Can adopt the little cranium super hole cutter of manual and electric double-purpose, little cranium super hole cutter has an accumulator (referring to Figure 12,13) that power supply can be provided below handle 14, driving electric arbor after the motor energising, motor reel drive drill bit shaft and the rotation of drill bit locker, rotate thereby drive drill bit.Little cranium super hole cutter rotates under the drive of motor, has reduced patient's physical work, can make the drill bit smooth rotation again.But when having unavoidably accumulator and also not having electricity and need to carry out emergency operation, this moment the hexagon ring of one end of joystick is enclosed within the axle head hexagon prism of rocking handle, hand axle of starting rocking bar and rocking handle just can be by travelling gear and power transmission shaft driving electric arbor and drill bit shaft and drill bit rotation work.This design is that the patient provides convenience and has considered the burst factor for the patient.

Embodiment 3, a kind of locating holes electric drill for taking out foreign body in head of the present invention, organism 81, be arranged in body electric driving mechanism 82 with the coaxial drill bit that is connected 80 of driving mechanism output shaft, the body front end is with launching the planar

light laser instrument

83,84,85,86 that intersects at drill axis.As shown in Figure 14,15, wherein, the planar light of planar

light laser instrument

83,85 emissions is same plane, is the vertical plane of front view; The planar light of planar light laser instrument 84,86 emissions is same plane, is the horizontal plane of front view.Figure

midplane light laser

83,85 is fixed on body front end up and down, sends same plane light, and planar light and motor axis, drill axis are coplanar.The laser instrument 84,86 of adjustable planar light is arranged on adjustment ring 87, and adjustment ring and body front end cylinder interference fits are rotationally connected, and adjustable planar light laser instrument 84,86 can be along with adjustment ring is rotated around axis.Adjustable planar light laser instrument 84,86 sends same plane light, and planar light and motor axis, drill axis are coplanar, intersects at axis with fixing planar light simultaneously, forms adjustable planar light.Adjustable planar light can be according to the angle of head surface reticule, rotate adjustment ring, make the crossing angle of adjustable planar light and fixing planar light, reach consistent, and two intersecting plane light are when the head surface projection line overlaps with the head surface reticule, just just in time make the axis of drill bit pass the hematoma center, keep the accurate direction of boring.Form two and intersect planar light, also quite simulate the plane of passing the hematoma center on the CT sheet.Keep at any time like this direction of laser beam according to the head surface setting-out, when the setting-out of laser beam and head surface keeps overlapping, the point that laser beam intersects just in time with the drill bit of brill and foreign body center on same straight line, keep accurately the direction of perforate and puncture.

Embodiment 4, a kind of the present invention are used for taking out foreign body locating holes hand drill in head, and organism 91 is arranged in body and in the rotating shaft 92 movingly of body two ends, forms Manual drive mechanism.With the coaxial drill bit that is connected 93 of Manual drive mechanism rotating shaft outfan, this drill bit can be fixing by being arranged on rotating shaft outfan drill bit locker 94.The rotating shaft of Manual drive mechanism is stretched out above body, and with turning handle 95.The body side with hold 90.The body front end is with four

radial plate

96,97,98,99, and wherein two 96,97 on same plane, is fixedly connected with body retainer ring 100; Be rotationally connected by turning set 101 interference fits with body in another same plane for another two 98,99, can be locked by nut arranged side by side 102 after rotational positioning, nut is threaded with body.Two Plane intersects, intersecting lens and drill axis are collinear.Two radial plate that are rotationally connected by turning set and body interference fits just change and another two radial plate relative angles at relative body rotation process, come the angle that intersects in head surface meld line (projection line) with the foreign body center consistent.Like this with hand drill when the perforate of head meld line cross point, observe to the drill bit direction from the hand drill rear end, keep four radial plate to cover the meld line of two intersections in the projection line correspondence of head surface, just can keep bit heading foreign body center, guarantee perforate direction accurately.

Claims

1. positioning rule of be used for taking out foreign body location and perforate location multiaspect cylindrical void in head, orthogonal two flat boards are arranged, flat board has cylindrical void, it is characterized in that: connect and compose three panels by a rebound between two flat boards, the plate face of three panels has vertical cylindrical void or the horizontal cylindrical void of arrangement, the plate face is also with the size scale of vertical and horizontal, a flat board of three panels is parallel with the corresponding flat board of another piece three panels, and these two three panels dull and stereotyped relative sliding of correspondence in addition connect; Described two three panels dull and stereotyped relative sliding of correspondence in addition connect, it is chute that flat board has in the flat board of correspondence that two three panel relative slidings are connected, another dull and stereotyped correspondence position has screw, screw passes chute and is connected with screw, forms two corresponding dull and stereotyped being slidably connected.

2. the positioning rule for taking out foreign body location and perforate location multiaspect cylindrical void in head as claimed in claim 1 is characterized in that: two flat boards during dull and stereotyped relative sliding connects, one flat plate has cylindrical void, another relatively flat board be empty frame.