CN201845166U

CN201845166U - Improved portable structure of translucent screen

Info

Publication number: CN201845166U
Application number: CN 201020566809
Authority: CN
Inventors: 陈英文
Original assignee: Individual
Current assignee: Individual
Priority date: 2010-10-18
Filing date: 2010-10-18
Publication date: 2011-05-25
Anticipated expiration: 2020-10-18

Abstract

The utility model provides an improved portable structure of a translucent screen. The structure comprises a first support frame and a second support frame as well as a translucent screen, wherein one end of the translucent screen is retracted in the first support frame , and the other end is connected with the second support frame; and a foldable X-shaped (or double X-shaped) connecting rod group is arranged between the first support frame and the second support frame, the connecting rod group is utilized to serve as the support frame of the expanded translucent screen, and when the translucent screen is folded, the X-shaped (or double X-shaped) connecting rod group can be folded in the first support frame to reduce the volume of the folded translucent screen, thereby facilitating carrying.

Description

Improved Portable projection screen structure

Technical field

The utility model relates to a kind of improved Portable projection screen structure, is meant a kind of bracing frame that can fold that has itself especially, is beneficial to collect the improved Portable projection screen structure that carries.

Background technology

Projector's cloth curtain commonly used is most for hanging the structure of wall type projection screen, its structure comprises a side-scrolling device of laterally hanging on indoor wall haply, this reel device is provided with a rollable cloth curtain, and utilizes electro-motor or manual mode to control the action of furling of this cloth curtain or lowering.

This kind hangs the purposes that the wall type projection screen is applied in fixed large-scale projection screen usually, and its volume is quite huge, and weight is quite heavy, and is to be fixedly mounted in the fixed place such as classroom, meeting room, audiovisual studio, and can't arbitrarily move use.

Other has the projection screen of part, adopts portable structure, and the portable projection screen of the type has a rollable projection screen usually, and a height adjustable support.This support can this projection screen launches the back be set up in ground in upright mode, and when projection screen time spent not, after projection screen and support can being taken apart, furls respectively or is folded together, and is beneficial to carrying and storage.

Though this kind packaged type projection screen has transportable characteristic, its projection screen is split as two different assemblies with support, therefore must carry two assemblies respectively when carrying, causes the difficulty of carrying work.The structure of Chang Yong projection screen bracket is generally the structure of utilizing a telescopic upright body of rod to rise as the support projection curtain in addition, therefore after projection screen rises, its top has only the single strong point, cause the projection screen strong point must be, otherwise will crank take place and the situation that tilts produces in centre.

In recent years because projector's universalness, and small-sized projector, or the technology of portable projector is day by day ripe, the market demand to commercial bulletin is increasing, especially can provide the projection screen of carrying also relative needs, large-scale projection screen commonly used little by little can't satisfy the demand in micro projection curtain market, and therefore the generation of small-sized and light Portable projection screen is arranged.

The Portable projection screen that the type is small-sized and light, be projection screen and support to be integrated into one structure, but the support of its use, it also is the structure of the single flexible upright body of rod, after making that projection screen launches, its top also is the support that single-point is only arranged, and therefore also is easy to generate projection screen and supports shakiness, the situation of rocking easily.

In addition, more have easy flat projection curtain as the picture A4 paper size to produce, so because it can't fold area and can't strengthen, otherwise will carry inconvenience, therefore can't satisfy the demand in micro projection market, this is a big shortcoming.

Owing to above reason, make projector's projection screen commonly used that further improved demand be arranged, the designer is in view of this, be to think hard funiculus, active research is engaged in the experience that Related product is studied for many years, and through continuous test and improve, develop finally and the utility model.

The utility model content

The purpose of this utility model is to be to provide a kind of improved Portable projection screen structure, and it is easy to carry in light weight, and projection screen can arbitrarily furl, and supporting construction is firm.

For this reason, the utility model proposes a kind of improved Portable projection screen structure, comprising: one first bracing frame, inside is provided with a spool; And a projection screen, an end is connected in this spool, and is wound on this spool, and the other end is a movable end; And one second bracing frame, linearly be connected with the movable end of this projection screen, and can rise in parallel or descend with this first bracing frame, become the state that launches or furl and drive this projection screen, wherein:

Between this first bracing frame and second bracing frame, be provided with a connection rod set, this connection rod set has two isometric connecting rods, the center section part branch of this two connecting rod is articulated mutually, and with the X-shaped intersection, the one end is a support end, and this support end is articulated in respectively on this first and second bracing frame, and the other end is a sliding end, and this sliding end is connected between this first and second bracing frame in the mode that can slide along the length direction of this first and second bracing frame;

By the said apparatus combination, two connecting rods of this connection rod set can link together this first and second bracing frame, and when this projection screen launches, this first and second bracing frame support are positioned a relative expanded position, make this projection screen keep deployed condition.

Aforesaid improved Portable projection screen structure wherein is respectively equipped with first guide member and second guide member along its length direction on this first bracing frame and this second bracing frame; The sliding end of two connecting rods of aforementioned connection rod set is respectively equipped with interface components, and described interface components is sliding engaged to described first and second guide member respectively; Cooperate with this two interface components by above-mentioned first and second guide member, the sliding end of bootable this two connecting rod is along the length direction linear reciprocation displacement of this first and second bracing frame.

Aforesaid improved Portable projection screen structure, wherein this first and second guide member is the guide channel with opening; Aforementioned two interface components are for being sticked in roller or the slide block in the aforementioned guide channel.

Aforesaid improved Portable projection screen structure wherein further is provided with at least one second group connection rod set between this connection rod set and this second bracing frame; This connection rod set of second group has with two connecting rods of aforementioned connection rod set isometric, and same two connecting rods with the X-shaped cross arrangement; The connecting rod of this connection rod set of first group and second a group of connection rod set close end mutually is articulated mutually; End near aforementioned first bracing frame and second bracing frame then articulates or is connected in slidably on this first and second bracing frame, make this first and second bracing frame can be close in parallel or away from.

Aforesaid improved Portable projection screen structure, wherein this second bracing frame has a planar portions that can recline for the movable end of aforementioned projection screen thereon; The terminal edge of the movable end of aforementioned projection screen is adhesive with a pressing plate, and should be pressed together on this planar portions by movable end by this pressing plate; And a clamping part, be arranged at this second bracing frame and be positioned at this planar portions marginal position, can with this pressing plate together with the edge pressing and fixing of the movable end of projection screen on this planar portions.

Aforesaid improved Portable projection screen structure, wherein this planar portions further is provided with a plurality of rags, with the movable end that increases this projection screen and the grasping force of this planar portions.

Aforesaid improved Portable projection screen structure, wherein this connection rod set further comprises a location mechanism, this detent mechanism comprises: a sliding seat is arranged at one of them sliding end of two connecting rods of this connection rod set; An and positioning seat, be arranged at contiguous this first bracing frame or second bracing frame, and be positioned at the contiguous stop place of an end under described projection screen deployed condition that is provided with the described connecting rod of described slip, make this sliding seat can be near this positioning seat when the projection screen deployed condition; Be respectively equipped with on aforementioned positioning seat and the sliding seat can in this sliding seat and positioning seat near the time, first and second fastener that is fastened togather mutually.

The utility model is between first and second bracing frame of projection screen, one X-shaped that can fold (or two X-shaped) connection rod set is set, utilize the bracing frame after this connection rod set is launched as projection screen, and when projection screen folds, the connection rod set of this X-shaped (or two X-shaped) can collapse among first bracing frame, to dwindle the volume after this projection screen folds, be beneficial to carry.

The utility model can launch the support of projection screen by the connection rod set of itself, do not need to use in addition body support in addition, and after folding, connection rod set collapses in first bracing frame of projection screen fully, and after it launches, but connection rod set is the firm support projection screen again, and makes projection screen be difficult for rocking.

Description of drawings

Fig. 1 is the front view of improved Portable projection screen structure of the present utility model.

Fig. 2 is that the utility model is in the front view of projection screen near collapse state.

The side assembled sectional view that Fig. 3 is got in the projection screen collapse state for the utility model.

The side assembled sectional view that Fig. 4 is got in the projection screen deployed condition for the utility model.

The amplification view that Fig. 5 is got by the side of first bracing frame for the utility model.

The amplification view that Fig. 6 is got by the side of second bracing frame for the utility model.

The three-dimensional combination figure that Fig. 7 is got in the projection screen deployed condition for the utility model.

The detent mechanism that Fig. 8 uses for the utility model is installed on the partial enlarged view on second bracing frame.

The detent mechanism that Fig. 9 uses for the utility model is installed on the vertical view under the mutual buckle state.

Figure 10 is the front view of the utility model second embodiment, in order to disclose the utility model in the embodiment that the connection rod set more than a group is set between first and second bracing frame.

The main element label declaration:

10 first bracing frames, 11 hollow cell bodies

12 openings, 13 precalculated positions

14 first guide members, 20 spools

30 projection screens, 31 movable ends

40 second bracing frames, 41 second guide members

42 pressing plates, 43 planar portions

44 rags, 45 clamping parts

50 foot rests

60 connection rod set, 61 connecting rods

62 connecting rods, 63 interface components

64 interface components

60B connection rod set 61B connecting rod

62B connecting rod 63B interface components

65 support ends, 66 support ends

67 axle center, 68 sliding ends

69 sliding ends

70 detent mechanisms, 71 positioning seats

72 sliding seats, 73 first fasteners

74 second fasteners, 75 scratching parts

76 scratching parts, 77 press sections

78 fixtures

Embodiment

Understand for technical characterictic of the present utility model, purpose and effect being had more clearly, now contrast description of drawings embodiment of the present utility model:

As shown in Figures 1 to 4, improved Portable projection screen structure of the present utility model mainly comprises: one first bracing frame 10, adopt in light weight and firm aluminium extruded type material to make the elongate frame of first bracing frame 10, its shape is elongated rod shape, and inside is hollow form, and forms a hollow cell body 11; And the spool 20 of an elongated rod shape, this spool 20 is rotatably installed in the hollow cell body 11 of this first bracing frame along the central axis of this first bracing frame; An and projection screen 30, one end is connected in this spool 20 and is wound on this spool 20, and the other end is a movable end 31, be provided with one second bracing frame 40 in this movable end 31, linearly be connected with this movable end 31, so as to making the movable end 31 of this projection screen 30 keep linear state at any time.

Has a scrolling spring (not shown) on the aforementioned spool 20, when this projection screen 30 launches, can drive these spool 20 rotations and make this scrolling spring, and can drive this spool 20 backrush, so that this projection screen 30 is furled on this spool 20 by the stored elastic force of this scrolling spring by rolling-in.

This second bracing frame 40 can rise in parallel or descend with this first bracing frame 10, becomes the state that launches or furl and drive this projection screen 30.As shown in Figures 3 and 4, the end face of this first bracing frame 10 has an opening 12, the movable end 31 of projection screen 30 and second bracing frame 40 can pass from this opening 12, when this projection screen 30 furls in spool 20 fully, this second bracing frame 40 can be accommodated in opening 12 parts of this first bracing frame 10, and when projection screen 30 launched, the user can be pulled upwardly this second bracing frame 40, and makes this projection screen 30 become deployed condition.

The bottom of aforementioned first bracing frame 10 further is provided with at least one foot rest 50, can be supported in ground, this first bracing frame is placed on the ground abreast, and can when projection screen 30 launches, can this first bracing frame 10 be placed on ground or the desktop perpendicular to ground or desktop ground.

The feature that the utility model is main, be to be to be provided with a connection rod set 60 between this first bracing frame 10 and second bracing frame 40, with so that this second bracing frame 40 can rise in parallel or descend with this first bracing frame 10, and when this projection screen 30 launches, support this projection screen 30 and make it keep deployed condition.

This connection rod set 60 has two connecting

rods

61,62; Aforementioned connecting

rod

61,62 is X-shaped and intersects, and the stage casing part utilizes an axle center 67 to be articulated.And as shown in Figures 1 and 2, this two connecting

rod

61,62 has a

support end

65,66 respectively, be articulated in respectively on this first bracing frame 10 and second bracing frame 40 with position that a precalculated position 13 is aimed on; And this two connecting

rod

61,62 then is a sliding

end

68,69 with respect to the other end of this two

support end

65,66, but is connected on this first and second bracing

frame

10,40 in the mode of linear slide.

As shown in Figure 2, because the

support end

65,66 of this two connecting

rod

61,62 is separately fixed on first and

second support

10,40, therefore when second bracing frame 40 is subjected to pulling force away from first bracing frame 10, the

support end

65,66 of this two connecting

rod

61,62 also can produce relative displacement together along with this first and second bracing

frame

10,40.

This moment is because this two connecting

rod

61,62 central authorities are subjected to axle center 67 restrictions, and add axle center 67 and be positioned at this two connecting

rod

61,62 centre position, therefore make this two connecting

rod

61,62

support end

65,66 along with first, two supports 10, in the time of 40 relative displacements, this two connecting rod 61, the sliding end 68 of 62 other ends, 69 also can produce with this axle center 67 be the center and with this two

support end

65,66 symmetrical relative displacements, therefore make this two sliding

end

68,69, can be respectively first, two bracing

frames

10,40 first, two guide members 14, slide in parallel in 41, launch or furl and drive projection screen 30.

As shown in Figure 2, when the sliding

end

68,69 of this two connecting

rod

61,62 in first and

second guide member

14,41 of this first and second bracing

frame

10,40 towards with an end of its

support end

65,66 away from direction when sliding, can make the hypotelorism of this first and second bracing

frame

10,40, and when this two connecting

rod

61,62 drops near overlapping state, this second bracing frame 40 will fully be folded in first bracing frame 10, and make projection screen 30 fully furl inside (as shown in Figure 4) in first bracing frame 10.

And when the sliding

end

68,69 of this two connecting

rod

61,62 in first and

second guide member

14,41 of this first and second bracing

frame

10,40 when the end with its

support end

65,66 slides near direction, the top of this connection rod set 60 can upwards be risen, and these first and second bracing

frame

10,40 spacings are elongated, and make this projection screen become deployed condition (as Fig. 1 and shown in Figure 4).

As Fig. 5, Figure 6 and Figure 7, the length direction of this first bracing frame 10 in a side of its hollow groove body 11 along first bracing frame 10 is provided with one first guide member 14, and the sliding end 69 of this connecting rod 62 is provided with an interface components 64, slidably is connected mutually with this first guide member 14; And the back side of this second bracing frame 40, also the length direction along second bracing frame 40 is provided with one second guide member 41, and is provided with an interface components 63 in the sliding end 68 of this connecting rod 61, slidably is connected mutually with this second guide member 41.Employed first and

second guide member

14,41 is the groove that one one side has opening among this embodiment, and this

interface components

63,64 is for being arranged in slide block or the roller in the aforementioned grooves slidably, therefore make the sliding

end

68,69 of this two connecting

rod

61,62, can be hard to bear these first and

second guide member

14,41 restrictions, and along with the length direction shift reciprocately of this first and second bracing

frame

10,40.

As shown in Figure 7, when two connecting

rods

61,62 of connection rod set 60 of the present utility model slidably an end is stretched over the extreme higher position time, this projection screen 30 is launched fully, and by the support frame of this connection rod set 60 as this second bracing frame 40 and projection screen 30, and after making that this projection screen 30 launches, can be kept upright, for the image projecting of projector on this projection screen 30.

In addition, the utility model further is provided with a location mechanism 70 on this second bracing frame 40, in order to when this projection screen 30 launches, this connection rod set 60 is positioned deployed condition.As Fig. 8 and shown in Figure 9, this detent mechanism 70 includes: a positioning seat 71 is arranged among second guide member 41 on this second bracing frame 40; Reach a sliding seat 72, be connected in the sliding end 68 of this connecting rod 61.The sliding end that the position that aforementioned positioning seat 71 is provided with is adjacent to aforementioned connecting rod 61 in this connection rod set 60 rise to most significant digit to the time the stop place, therefore make this sliding seat 72 after this projection screen 30 launches, can be close to this positioning seat 71.

As shown in Figure 9, the close mutually side of this positioning seat 71 and sliding seat 72 is respectively equipped with first a relative fastener 73 and second fastener 74.Be respectively equipped with a

relative scratching part

75,76 on this first and

second fastener

73,74; This two scratching

part

75,76 can in this sliding seat 72 and positioning seat 71 near the time be fastened togather mutually, and make this sliding seat 72 link together with positioning seat 71, be positioned on the aforesaid stop place so as to sliding end 68 this connecting rod 61.

Positioning seat 71 can move arbitrary position among second guide member 41, this position can determine the height that projection screen 30 launches, when required height wanted higher, (as screw) fixed with fixture 78 then in the support end 66 dislocation desired positions in 71 past guide members 41 of positioning seat.

On this external this first fastener 73 or second fastener 74, one press section 77 can be set, depress this first fastener 73 or second fastener 74 for the user with finger, make these first or second fastener, 73,74 bendings and make scratching

part

75,76 break away from mutually, so that but the sliding end of the connecting rod 61 of sliding seat 72 and first connecting rod group 60 becomes free movement state, so that the first connecting rod group 60 and second bracing frame 40 are oppositely furled.

In this mandatory declaration is that the positioning seat 71 and the sliding seat 72 of above-mentioned detent mechanism 70 is arranged on the sliding end of second bracing frame 40 and connecting rod 61.But during practice, this positioning seat 71 also is can change on the sliding end that is arranged on first bracing frame 10 and connecting rod 62 with sliding seat, and its effect of bringing into play is duplicate with previous embodiment.

In addition, another improvements of the utility model are the combination between this projection screen 30 and second bracing frame 40, can not produce the crape pleat after making this projection screen 30 and this bracing frame 40 combining, so that projection screen 30 is kept smooth no wave state after launching.As shown in Figure 6, the leading flank of this second bracing frame 40 has a planar portions 43, can fit for the movable end 31 of aforementioned projection screen 30; Be provided with the rag 44 of a plurality of protrusion dentations in this planar portions 43, to increase the on-slip power of this movable end 31 and this planar portions 43; And be provided with the clamping part 45 that turns to following bending after an edge from this planar portions 43 extends forward again above the planar portions 43.

The fixed form of the movable end 31 of this projection screen 30, be attached on the pressing plate 42 of a rectangular en plaque to paste high viscosity and resistant to elevated temperatures double faced adhesive tape mode earlier prior to the terminal of movable end 31, then pressing plate 42 is inserted in the clamping part 45 of second bracing frame 40 together with the movable end 31 of projection screen 30, when pulling out, projection screen 30 just can be subjected to the pulling force that furls spring established in the spool 20, continue downward pulling force and form one, this pulling force can make the inclined surface in inclined-plane on the pressing plate 42 and the clamping part 45 form the horizontal slippage of wedge shape, and projection screen 30 is clamped in its slot, the rag 44 that is protruded simultaneously dentation inserts in the base material of projection screens 30 and projection screen 30 firmly and is effectively clamped and can not come off, reach firm purpose, and can guarantee that projection screen 30 is smooth no wavy.

As shown in figure 10, be another embodiment of the utility model, among this embodiment, between this first and second bracing

frame

10,40, be provided with the connection rod set 60 more than a group, therefore can be by the connection rod set more than a group 60 be combined, to increase the spacing that first and second bracing frame 40 launches, so as to making technology of the present utility model can be applied on the larger sized projection screen.

As shown in figure 10, when the utility model when 10,40 of first and second bracing frames are set up second group connection rod set 60B, this second group of newly-increased connection rod set 60B also is and first group of connection rod set 60 is connected between the connection rod set 60 and second bracing frame 40 with the X-shaped interleaved mode equally; One end of connecting rod 61B, the 62B of this connection rod set 60B and close this connection rod set 60 is articulated across with this connecting

rod

61,62 respectively, and connecting rod 62B then is articulated on the position in alignment with aforementioned precalculated position 13 of this second bracing frame 40 near an end of this second bracing frame 40; And the sliding end of connecting rod 61B is provided with an interface components 63B, and is slidably connected to interface components 63B among second guide member 41 of this second bracing frame 40.

Improved Portable projection screen structure of the present utility model is compared down with projection screen commonly used, and therefore the bracing frame that it can utilize aforementioned first connecting rod group 60 to launch as the support projection curtain does not need to use in addition support again, just projection screen can be launched for use.This connection rod set 60 is when projection screen folds simultaneously, can be accommodated in first bracing frame, 10 inside fully, and the volume-diminished after it is folded, be beneficial to carry, this connection rod set 60 is made up of 61,62 on first and second connecting rod adopting the X-shaped arrangement simultaneously, after it launches, can be so that second bracing frame 40 obtain firm support, and can arbitrarily not rock when it is used.

In addition, improved Portable projection screen of the present utility model also can be according to user demand, change the length of first bracing frame 10 and second bracing frame 40, arrange in pairs or groups the simultaneously length variations of first and second connecting

rod

61,62, and can produce the Portable projection screen of different size easily, this is the demand that the utility model meets multi-size on the market.

The above only is the schematic embodiment of the utility model, is not in order to limit scope of the present utility model.Any those skilled in the art, equivalent variations of having done under the prerequisite that does not break away from design of the present utility model and principle and modification all should belong to the scope that the utility model is protected.

Claims

1. improved Portable projection screen structure, comprising:

One first bracing frame (10), inside is provided with a spool (20); And

One projection screen (30), an end are connected in described spool (20), and are wound on the described spool (20), and the other end is a movable end (31); And

One second bracing frame (40), can rise in parallel or descend with described first bracing frame (10) and can drive the movable end that is arranged at described projection screen that described projection screen launches or furls, and linearly be connected with the movable end (31) of described projection screen (30);

It is characterized in that:

Between described first bracing frame (10) and second bracing frame (40), be provided with a connection rod set (60), described connection rod set (60) have two isometric, can be with described first, two bracing frames (10,40) connecting rod (61 that links together, 62), this two connecting rod (61,62) center section part branch is articulated mutually, and intersect with X-shaped, the one end is a support end (65,66), described support end is articulated in described first respectively, two bracing frames (10,40) on, and the other end is a sliding end (68,69), described sliding end (68,69) can be along described first, two bracing frames (10,40) length direction is connected to described first in the mode of sliding, two bracing frames (10,40) between.

2. improved Portable projection screen structure as claimed in claim 1 is characterized in that, alongst is respectively equipped with first guide member (14) and second guide member (41) on described first bracing frame (10) and described second bracing frame (40); The sliding end (68,69) of two connecting rods of described connection rod set (60) (61,62) is respectively equipped with interface components (63,64), and described interface components (63,64) is sliding engaged to described first and second guide member (14,41) respectively; Described first and second guide member (14,41) cooperates the sliding end (68,69) that can guide this two connecting rod (61,62) the length direction linear reciprocation displacement along described first and second bracing frame with this two interface components (63,64).

3. improved Portable projection screen structure as claimed in claim 2 is characterized in that, described first and second guide member (14,41) is for having the guide channel of opening; Two described interface components (63,64) are for being sticked in roller or the slide block in the described guide channel.

4. improved Portable projection screen structure as claimed in claim 3 is characterized in that, between described connection rod set (60) and described second bracing frame (40) at least one second group connection rod set (60B) is set further; Described second group connection rod set (60B) has with two connecting rods (61,62) of described connection rod set (60) isometric, and same two connecting rods (61B, 62B) with the X-shaped cross arrangement; The close mutually end of the connecting rod of described first group connection rod set (60) and second group of connection rod set (60B) (61,62,61B, 62B) is articulated mutually, then articulates near an end of described first bracing frame (10) and second bracing frame (40) maybe can be slidably connected on this first and second bracing frame (10,40).

5. improved Portable projection screen structure as claimed in claim 1 is characterized in that, described second bracing frame (40) has a planar portions (43) that can recline for the movable end (31) of described projection screen (30); The terminal edge of the movable end (31) of described projection screen is adhesive with a pressing plate (42), and described movable end (31) can be pressed together on the described planar portions (43) by described pressing plate (42); Reaching one can be arranged at edge pressing and fixing the clamping part (45) on described planar portions (43) of described pressing plate (42) together with the movable end (31) of described projection screen (30) described second bracing frame (40) and be positioned at described planar portions (43) marginal position.

6. improved Portable projection screen structure as claimed in claim 5 is characterized in that, described planar portions (43) further is provided with the rag (44) of the grasping force of a plurality of movable ends that can increase described projection screen and described planar portions.

7. improved Portable projection screen structure as claimed in claim 1, it is characterized in that, described connection rod set (60) further comprises a location mechanism (70), described detent mechanism (70) comprising: a sliding seat (72) is arranged at one of them sliding ends (68,69) of two connecting rods (61,62) of described connection rod set (60); And a positioning seat (71), be arranged at described first bracing frame (10) or second bracing frame (40), and be positioned at the contiguous stop place of an end under described projection screen (30) deployed condition that is provided with the described connecting rod (61,62) of described sliding seat (72); Be respectively equipped with first and second fastener (73,74) that when described sliding seat and positioning seat are close, can be fastened togather mutually on described positioning seat (71) and the sliding seat (72).