CN219594749U

CN219594749U - Isolated skin gets skin auxiliary device

Info

Publication number: CN219594749U
Application number: CN202321214571.6U
Authority: CN
Inventors: 张颖; 陈辉; 蒋徽豪
Original assignee: Individual
Current assignee: Beijing Jishuitan Hospital Affiliated To Capital Medical University
Priority date: 2023-05-19
Filing date: 2023-05-19
Publication date: 2023-08-29
Anticipated expiration: 2033-05-19

Abstract

The utility model provides an isolated skin taking auxiliary device, and belongs to the technical field of medical appliances. In the skin grafting technique, it is necessary to remove a layer of epidermis from the surviving skin tissue and graft it to other damaged sites. When the source skin tissue is derived from the isolated skin, the isolated skin is soft and wrinkled due to the fact that the support of the subcutaneous muscle tissue is not provided, and the skin removing machine is difficult to remove the skin from the surface layer of the isolated skin. The utility model relates to an isolated skin taking auxiliary device which comprises a base, an air bag and a plurality of clamping parts, wherein the air bag is arranged on the inner side of the base, the clamping parts are arranged on the periphery of the base, during operation, the clamping parts clamp a plurality of positions of isolated skin and tighten the isolated skin, and then the air bag supports the isolated skin from the bottom to enable the isolated skin to be in a tightened and slightly raised state, so that a skin taking machine can conveniently take off a skin layer for transplantation from the surface layer of isolated source skin tissue.

Description

Isolated skin gets skin auxiliary device

Technical Field

The utility model belongs to the technical field of medical appliances, and particularly relates to an isolated skin taking auxiliary device.

Background

In the skin grafting technique, it is necessary to remove a layer of epidermis from the surviving skin tissue and graft it to other damaged sites. The skin used to extract the graft layer may be derived from the skin of other parts of the patient himself or from the skin that has been ex vivo. When the source skin tissue is isolated, the skin tissue is in a soft and wrinkled cluster due to the lack of the support of subcutaneous muscle tissue, and the skin taking process is quite inconvenient to operate.

In the prior art, the assistant is generally used for assisting in spreading the skin surface, the doctor controls the pressure of the downward pressing of the blade to control the thickness of the cut skin, the operation is more inconvenient, the requirements on the degree of default of the doctor and the assistant are high, even so, the quality of the extracted skin layer is difficult to ensure, and even the waste and damage of the isolated skin tissue are caused, so that the secondary injury is brought to the patient.

Disclosure of Invention

In view of the above-mentioned drawbacks of the prior art, an object of the present utility model is to provide an isolated skin taking-out assisting device for solving the problem that in the prior art, isolated skin tissue is soft and wrinkled due to lack of support of subcutaneous muscle tissue, and the skin graft layer is inconvenient to extract.

In order to achieve the above and other related objects, the present utility model provides an in-vitro skin taking auxiliary device for taking skin from an in-vitro skin surface layer, comprising a base, an air bag and a plurality of clamping parts, wherein the air bag is arranged on the inner side of the base, and the plurality of clamping parts are arranged on the circumference of the base.

Optionally, the clamping part includes clip, connecting piece and grip slipper, the grip slipper set up in on the base, the connecting piece connect in between the clip with the grip slipper.

Optionally, the connecting piece is a flexible cable.

Optionally, the clamping seat comprises a rotating rod and a mounting block, the mounting block is connected to the base, a through hole is vertically formed in the mounting block, and the upper section of the through hole is a circular section, and the lower section of the through hole is a polygonal section;

the rotating rod is inserted into the through hole, and the bottom of the rotating rod is also provided with a polygonal section and is matched with the polygonal section of the through hole;

when the polygonal section of the rotating rod is inserted only into the circular section of the through hole, the rotating rod can rotate;

when the polygonal section of the rotation lever is inserted into the polygonal section of the through hole, the rotation lever cannot rotate;

one end of the flexible rope is connected with the clamp, the other end of the flexible rope is connected with the rotating rod, and the rotating rod rotates and winds the flexible rope.

Optionally, the mounting block is slidably connected to the base through a sliding structure, and the sliding position is fixed by a locking structure.

Optionally, the sliding structure includes a sliding groove and a sliding surface disposed on the mounting block, the sliding groove is disposed on the periphery of the base around the air bag, and the mounting block is slidably mounted in the sliding groove;

the locking structure comprises two locking blocks and an elastic piece, wherein the two locking blocks are respectively connected to two ends of the elastic piece, a through locking hole is formed in the mounting block, the locking structure is located in the locking hole, one end of the locking structure is in surface contact with the sliding groove, and the other end of the locking structure is located in the through hole of the mounting block.

Optionally, an operating handle is arranged at the top end of the rotating rod.

Optionally, the clamping piece of the clamp is an 18-10 stainless steel metal piece.

Optionally, the balloon comprises a plurality of independently controlled inflation regions.

Optionally, the chute is provided with a notch, and the mounting block can be mounted in or removed from the notch.

As described above, the isolated skin taking auxiliary device of the utility model has at least the following beneficial effects:

the utility model provides an isolated skin taking auxiliary device which is convenient for extracting skin transplanting layers, comprising a base, an air bag and a plurality of clamping parts, wherein the air bag is arranged on the inner side of the base, the clamping parts are arranged on the periphery of the base, the clamping parts clamp a plurality of positions of isolated skin and tighten the isolated skin during operation, and the air bag supports the isolated skin from the bottom to enable the isolated skin to be in a tightened and slightly raised state, so that a skin taking machine is convenient for taking the isolated source skin transplanting layers for transplanting from the surface layer of isolated source skin tissues.

Drawings

Fig. 1 shows an overall schematic of the present utility model.

Fig. 2 is a schematic view of a clamping seat according to the present utility model.

Fig. 3 shows a cross-sectional view of the clamping seat of the present utility model.

Fig. 4 is a schematic view of a locking structure of a clamping seat according to the present utility model.

Fig. 5 shows a schematic overall axial side view of the present utility model.

Fig. 6 shows an overall top view of the present utility model.

Fig. 7 shows a cross-sectional view of the B-B of fig. 6 in accordance with the present utility model.

FIG. 8 is an enlarged view of the chute A of FIG. 5 according to the present utility model.

Fig. 9 is an enlarged schematic view showing the locking structure at C in fig. 7 according to the present utility model.

Fig. 10 is an enlarged view showing the locking structure at C in fig. 7 according to the present utility model.

Fig. 11 shows a schematic overall view of the present utility model.

Wherein: the airbag cushion comprises a base 1, an airbag 2, an inflation area 21, a clamping part 3, a clip 31, a connecting piece 32, a clamping seat 33, a rotating rod 331, an operating handle 3311, a mounting block 332, a through hole 3321, a sliding surface 3322, a locking hole 3323, a polygonal section 34, a sliding structure 4, a sliding groove 41, a notch 42, a locking structure 5, a locking block 51, an elastic piece 52 and a skin 6.

Detailed Description

Further advantages and effects of the present utility model will become apparent to those skilled in the art from the disclosure of the present utility model, which is described by the following specific examples.

Please refer to fig. 1 to 11. It should be understood that the structures, proportions, sizes, etc. shown in the drawings are for illustration purposes only and should not be construed as limiting the utility model to the extent that it can be practiced, since modifications, changes in the proportions, or adjustments of the sizes, which are otherwise, used in the practice of the utility model, are included in the spirit and scope of the utility model which is otherwise, without departing from the spirit or scope thereof. Also, the terms such as "upper," "lower," "left," "right," "middle," and "a" and the like recited in the present specification are merely for descriptive purposes and are not intended to limit the scope of the utility model, but are intended to provide relative positional changes or modifications without materially altering the technical context in which the utility model may be practiced.

The following examples are given by way of illustration only. Various embodiments may be combined and are not limited to only what is presented in the following single embodiment.

Referring to fig. 1 and 5, the present utility model provides an in-vitro skin taking auxiliary device for taking skin from a tissue surface layer of in-vitro skin 6, which comprises a base 1, an air bag 2 and a plurality of clamping parts 3, wherein the air bag 2 is arranged at the inner side of the base 1, and the plurality of clamping parts 3 are arranged at the periphery of the base 1.

In the skin transplantation technology, in some situations, a skin layer for transplantation needs to be extracted from an isolated skin tissue, and in actual operation, the isolated skin tissue is in a soft and wrinkled shape due to lack of support of subcutaneous tissues, and when a doctor operates, the isolated skin tissue needs to be unfolded and supported on the bottom surface by an assistant, and then the doctor uses a skin removing knife to remove skin from the top layer of the isolated skin. At this moment, the assistant supports the bottom of the isolated skin tissue, and the doctor's skin taking knife is positioned at the top of the isolated skin tissue, so that in the operation process, the requirement on the degree of fit between operators is high, the width and the thickness of the extracted transplanting layer are difficult to ensure, the damage and the waste to the source skin tissue are easily caused, and further, the secondary injury is brought to the patient.

In this embodiment, the air bag 2 is disposed inside the base 1, and the inflation state of the air bag 2 and the tightness of the surface of the air bag 2 can be changed by inflating or deflating the air bag 2, and a plurality of clamping portions 3 are disposed on the outer periphery of the air bag 2, wherein the clamping portions 3 are connected to the base 1. In specific implementation, a plurality of clamping parts 3 can be arranged according to the unfolding shape of the isolated skin 6, so that a plurality of parts of the isolated skin 6 are clamped and properly tightened to be unfolded into a surface shape, then the air bag 2 is inflated, the air bag 2 is supported from the bottom of the isolated skin 6 which is tightened and unfolded, so that the isolated skin 6 is properly tightened into a bulge shape, a doctor can conveniently extract a transplanting layer, the matching degree requirement of the cooperative operation of a plurality of people is reduced, and the extraction efficiency and quality of the transplanting layer are improved.

Referring to fig. 1, the clamping portion 3 includes a clip 31, a connecting member 32, and a clamping seat 33, the clamping seat 33 is disposed on the base 1, and the connecting member 32 is connected between the clip 31 and the clamping seat 33. In practice, the ex-vivo skin 6 for extracting the graft layer may have various shapes, and is most advantageous for the doctor to operate when the ex-vivo skin 6 is in a stretched state and the circumference is suitably stretched. The periphery of the base 1 is provided with the plurality of clamping parts 3, the clamping parts 3 are connected with the clamp 31 through the connecting piece 32, the clamp 31 clamps and fixes the isolated skin 6, and the clamping distance of the clamp 31 can be changed by changing the length of the connecting piece 32, wherein the clamping distance refers to the distance from the edge of the base 1 to the center of the base 1, so that the isolated skin 6 with various shapes is adapted, and the applicability of the isolated skin 6 skin taking auxiliary device of the embodiment is further increased.

As a further aspect of the foregoing embodiment, the connector 32 is a flexible cord. The flexible cord is soft, so that the clamp 31 can be easily operated to clamp when the clamping action is required, and the clamp 31 can be loosened and moved to the outer side of the base 1 when the clamping action is not required, so that only part of the clamp 31 with the clamping action is reserved. Therefore, the space on the inner side of the base 1 can be reserved as far as possible, the operation space for a doctor to extract the skin graft layer is increased, the doctor can operate conveniently, and the quality and the efficiency for extracting the skin graft layer are improved.

Referring to fig. 2 and 3, the clamping seat 33 includes a rotating rod 331 and a mounting block 332, the mounting block 332 is connected to the base 1, the mounting block 332 is vertically provided with a through hole 3321, and an upper section of the through hole 3321 is a circular section and a lower section of the through hole 3321 is a polygonal section 34;

the rotating rod 331 is inserted into the through hole 3321, and the bottom of the rotating rod 331 is also provided with a polygonal section 34 and is matched with the polygonal section 34 of the through hole 3321;

when the polygonal section 34 of the rotation lever 331 is inserted only into the circular section of the through hole 3321, the rotation lever 331 may be rotated;

when the polygonal section 34 of the rotation lever 331 is inserted into the polygonal section 34 of the through hole 3321, the rotation lever 331 cannot be rotated;

one end of the flexible cable is connected with the clip 31, the other end is connected with the rotating rod 331, and the rotating rod 331 is used for winding the flexible cable in a rotating way.

As described above, the ex-vivo skin 6 for extracting the skin graft layer may have various shapes, and the distances of the respective holding positions are also correspondingly different when it is spread and stretched for the convenience of the doctor, as shown in fig. 5. Furthermore, the distances between the clips 31 and the clamping seats 33 are different, and in the previous embodiment, the clamping distance of each clip 31 can be changed by changing the length of the connecting piece 32, so that the isolated skin taking auxiliary device can adapt to isolated skin 6 tissues with various shapes.

In this way, however, each connection 32 needs to be adjusted according to the shape of the ex-vivo skin 6, and this adjustment is irreversible. For example, once the length of one of the connectors 32 is shortened to adapt to a specific ex-vivo skin 6, if the shape of the next ex-vivo skin 6 is changed, the connectors 32 need to be manufactured again, and the restoration adjustment cannot be performed on the basis of the previous time, so that not only is the material wasted, but also the process of adjusting the length of each connector 32 is time-wasted, and the two ends of each connector 32 need to be measured and fixed, which is disadvantageous to the operation, especially when the shape of the ex-vivo skin 6 for transplantation is complex and the clamping positions are more.

In this embodiment, the holder 33 includes a rotation lever 331 and a mounting block 332, the mounting block 332 is connected to the base 1, and the rotation lever 331 is inserted into a through hole 3321 of the mounting block 332. Both the rotation lever 331 and the through hole 332 have a circular section and a polygonal section, and when the rotation lever 331 is inserted downward into the through hole 332 until the polygonal section of the rotation lever 331 is fitted with the polygonal section of the through hole 3321, the rotation lever 331 cannot rotate in the mounting block 332 due to the restriction of the polygon.

If the rotation lever 331 is lifted upward, the polygonal section of the rotation lever 331 is separated from the polygonal section of the mounting block 332, and the rotation lever 331 can be rotated. The advantage of this is that the flexible cord can be wound onto the rotating rod 331 by rotating the rotating rod 331, so that the distance between the clip 31 and the clamping seat 33 is adjusted, and the clamping of the isolated skin 6 with different shapes is realized.

In the above-mentioned scheme, the cross section of the polygonal section may be triangle, rectangle, pentagon, etc., and the essence is to limit the rotation of the rotation rod 331 by using the straight edge cooperation between the cross sections, so as to fix the number of rotation turns of the rotation rod 331, that is, the length of the flexible cable that is fixedly wound, and further realize the adjustment and fixation of the clamping distance of the clamp 31. When the shape of the isolated skin 6 is changed, the rotating rod 331 is lifted upwards, so that the polygonal section between the rotating rod 331 and the mounting block 332 is separated, and the rotating rod 331 can be continuously rotated or reversely rotated at the moment, and longer flexible cables can be continuously wound or reserved, so that the isolated skin 6 with different shapes is adapted.

In the above embodiment, the debugging process of the device is simplified, and after the shape of the isolated skin 6 is changed, the device can be simply adjusted to be continuously applicable without cutting and reconnecting, and the adjusting process does not cause material consumption.

In this embodiment, referring to fig. 5, the mounting block 332 is slidably connected to the base 1 through the sliding structure 4, and the sliding position is fixed by the locking structure 5.

The shapes of the skin 6 may be different from each other, and in order to obtain an optimal clamping effect, the clamping may be performed at each protruding point of the skin 6, as shown in fig. 5. However, it is difficult to ensure that each of the holding portions 3 is just opposite to the protruding area of the separated skin 6, just because the shapes of the separated skin 6 are different.

Therefore, in this embodiment, the mounting block 332 may slide on the outer periphery of the base 1, and the sliding position thereof may be fixed, so that, in combination with the previous embodiment, both the clamping distance and the clamping angle are adjusted, thereby maximally improving the clamping effect, improving the convenience of doctor operation, and improving the extraction efficiency and quality of the skin graft layer.

As a specific solution of the above embodiment, referring to fig. 4, 5 and 8, the sliding structure 4 includes a sliding groove 41 and a sliding surface 3322 disposed on the mounting block 332, the sliding groove 41 is disposed on the outer periphery of the base 1 around the airbag 2, and the mounting block 332 is slidably mounted in the sliding groove 41;

the locking structure 5 comprises two locking blocks 51 and an elastic piece 52, the two locking blocks 51 are respectively connected to two ends of the elastic piece 52, a through locking hole 3323 is formed in the mounting block 332, the locking structure 5 is located in the locking hole 3323, one end of the locking structure 5 is in contact with the surface of the sliding groove 41, and the other end of the locking structure is located in the through hole 3321 of the mounting block 332.

The present embodiment specifically provides an embodiment of a sliding structure and a locking structure, which uses the above-described structure of the rotating rod 331 and the mounting block 332 for adjusting the winding amount of the flexible cable. The two sides of the mounting block 332 are sliding surfaces 3322, the sliding surfaces 3322 are provided with through locking holes 3323, locking structures 5 are arranged in the locking holes 3323, and one ends of the locking structures 5 are located in the through holes 3321.

Lifting the rotating rod 331, making the bottom end of the rotating rod 331 higher than the locking hole 3323 and the locking structure 5, wherein the elastic piece 52 of the locking structure 5 is in a natural telescopic state, no pressure exists on two sides, the mounting block 332 can slide freely in the sliding groove 41, during specific operation, the mounting block can slide to a corresponding clamping position of the isolated skin 6 according to the shape of the isolated skin 6, then the outer side of the isolated skin 6 is clamped by the clamp 31, then the rotating rod 331 is rotated, a flexible cable is wound, after the tightening state of the isolated skin 6 is properly regulated to a proper degree, the rotating rod 331 is pressed, a polygonal section of the rotating rod 331 is inserted into a polygonal section of the mounting block 332, and at the moment, the rotation of the rotating rod 331 is locked, and the clamping distance is fixed; meanwhile, during the pressing of the rotating rod 331, the side wall of the rotating rod 331 presses one end of the locking block 51 of the locking structure 5 located in the through hole 3321, please refer to fig. 9 and 10, wherein fig. 9 is a state before the pressing of the rotating rod 331, and fig. 10 is a state after the pressing of the rotating rod 331.

After the rotating rod 331 is pressed down, the side wall of the rotating rod 331 presses the locking structure 5, the elastic piece 52 of the locking structure 5 is compressed, a large elastic force is formed on the locking blocks 51 at the two ends of the locking structure, one side of the elastic force acts on the wall of the sliding chute 41 to form a friction force, and the sliding of the mounting block 332 is blocked, so that the position of the mounting block 332 and thus the clamping position are fixed; the other side of the elastic force acts on the rotating rod 331 to enhance the pressure and friction force to the rotating rod 331, so that the rotating rod 331 is firmly fixed. When the balloon begins to inflate and an upward supporting force is created on the ex-vivo skin 6, the force transmitted along the connector 32 to the rotating rod 331 will not pull it out.

In this embodiment, referring to fig. 11, an operating handle 3311 is provided at the top end of the rotating rod 331. The rotating rod 331 is an operating rod for adjusting the clamping distance, the clamping angle, the locking sliding position and the like, and has various operating modes of rotation, sliding, pressing, lifting and the like, and the operating handle can be arranged to facilitate operation, so that the operating convenience and the accuracy are improved.

As a further solution of the above embodiment, the clamping piece of the clamp 31 is a stainless steel sheet metal 18-10. The clip 31 is used for holding the ex-vivo skin 6, the bottom surface of the ex-vivo skin 6 is open skin tissue, and the ex-vivo skin 6 is living tissue, and the ex-vivo skin 6 is directly contacted with the clip 31, on one hand, the material of the clip 31 may damage the skin tissue, for example, metal ions in common iron materials may stimulate the skin tissue, affect the osmotic pressure thereof, and the like, particularly for open and damaged skin tissue; on the other hand, interstitial fluid in the skin tissue may also accelerate oxidative corrosion of clip 31. In the embodiment, the 18-10 stainless steel metal material is used, so that the isolated skin 6 can be protected, the transplanting survival rate can be improved, the clip 31 can be protected, and the oxidation corrosion can be delayed.

Referring to fig. 11, the airbag 2 includes a plurality of independently controlled inflation regions 21. When removing the skin from the surface layer of the isolated skin 6, the blade range of the skin removing knife is limited, and in order to obtain a better skin removing effect, the part of the skin removing knife is preferably protruded from other areas. In this embodiment, the airbag 2 has a plurality of inflation areas 21 that are independently controlled, and can make the local supporting height and the tightening degree higher than those of the peripheral area according to the specific skin taking position, so as to obtain better skin taking effect, facilitate the doctor's operation, and improve the skin taking amount and efficiency.

In this embodiment, referring to fig. 5 and 11, the chute 41 is provided with a notch 42, and the mounting block 332 can be inserted into or removed from the notch 42. The shape of the isolated skin 6 is various, and the parts to be clamped are different, and the sliding groove 41 is provided with a notch 42, so that the clamping part 3 can be added to the sliding groove 41 or the clamping part 3 can be reduced in a specific scene. The improvement is to find the most suitable clamping parts and clamping quantity for adapting to the shape of the isolated skin 6, and the unused clamping parts 3 can be taken out, so that the occupied space is reduced, and the doctor can operate conveniently. In addition, the clamping part 3 is taken out to facilitate cleaning and disinfection of the clamp and other parts, and then the clamp is reloaded into the chute 41 for use.

In summary, the utility model effectively overcomes various defects in the prior art, and has high industrial utilization value.

The above embodiments are merely illustrative of the principles of the present utility model and its effectiveness, and are not intended to limit the utility model. Modifications and variations may be made to the above-described embodiments by those skilled in the art without departing from the spirit and scope of the utility model. Accordingly, it is intended that all equivalent modifications and variations of the utility model be covered by the claims, which are within the ordinary skill of the art, be within the spirit and scope of the present disclosure.

Claims

1. The utility model provides an isolated skin (6) get skin auxiliary device for get skin from the skin (6) top layer of isolated, its characterized in that includes base (1), gasbag (2) and a plurality of clamping part (3), gasbag (2) are located base (1) inboard, a plurality of clamping part (3) set up in base (1) circumference.

2. An in vitro skin (6) taking aid as claimed in claim 1, wherein the clamping part (3) comprises a clamp (31), a connecting piece (32) and a clamping seat (33), the clamping seat (33) is arranged on the base (1), and the connecting piece (32) is connected between the clamp (31) and the clamping seat (33).

3. An ex-vivo skin (6) removal aid as claimed in claim 2, wherein the connector (32) is a flexible cord.

4. An ex-vivo skin (6) removal aid as claimed in claim 3, characterized in that:

the clamping seat (33) comprises a rotating rod (331) and a mounting block (332), the mounting block (332) is connected to the base (1), a through hole (3321) is vertically formed in the mounting block (332), and the upper section of the through hole (3321) is a circular section, and the lower section of the through hole is a polygonal section (34);

the rotating rod (331) is inserted into the through hole (3321), and a polygonal section (34) is also arranged at the bottom of the rotating rod (331) and is matched with the polygonal section (34) of the through hole (3321);

when the polygonal section (34) of the rotation lever (331) is inserted only into the circular section of the through hole (3321), the rotation lever (331) can be rotated;

when the polygonal section (34) of the rotation lever (331) is inserted into the polygonal section (34) of the through hole (3321), the rotation lever (331) cannot be rotated;

one end of the flexible rope is connected with the clamp (31), the other end of the flexible rope is connected with the rotating rod (331), and the rotating rod (331) rotates and winds the flexible rope.

5. An ex-vivo skin (6) peeling aid as claimed in claim 4, wherein the mounting block (332) is slidably connected to the base (1) by means of a sliding structure (4) and is secured in sliding position by a locking structure (5).

6. An ex-vivo skin (6) removal aid as claimed in claim 5, characterized in that:

the sliding structure (4) comprises a sliding groove (41) and a sliding surface (3322) arranged on the installation block (332), the sliding groove (41) is arranged on the periphery of the base (1) around the air bag (2), and the installation block (332) is slidably installed in the sliding groove (41);

the locking structure (5) comprises two locking blocks (51) and an elastic piece (52), the two locking blocks (51) are respectively connected to two ends of the elastic piece (52), a through locking hole (3323) is formed in the mounting block (332), the locking structure (5) is located in the locking hole (3323), one end of the locking structure (5) is in surface contact with the sliding groove (41), and the other end of the locking structure is located in the through hole (3321) of the mounting block (332).

7. An in vitro skin (6) taking out auxiliary device according to claim 4, characterized in that the top end of the rotating rod (331) is provided with an operating handle (3311).

8. An ex-vivo skin (6) removal aid as claimed in claim 2, wherein the gripping tab of the clip (31) is a sheet of 18-10 stainless steel metal.

9. An ex-vivo skin (6) skinning aid as claimed in claim 1, characterized in that the balloon (2) comprises a plurality of independently controlled inflatable regions (21).

10. An ex-vivo skin (6) removal aid as claimed in claim 6, wherein said chute (41) is provided with a notch (42), said mounting block (332) being insertable into or removable from said notch (42).