CN101502896B

CN101502896B - Hacksaws

Info

Publication number: CN101502896B
Application number: CN2008100742754A
Authority: CN
Inventors: 强尼·鲍瑞那图; 李祥庆
Original assignee: Positec Power Tools Suzhou Co Ltd
Current assignee: NANTONG BAOTIAN PACKING MACHINERY CO Ltd
Priority date: 2008-02-05
Filing date: 2008-02-05
Publication date: 2011-05-04
Anticipated expiration: 2028-02-05
Also published as: CN101502896A

Abstract

A hack saw (2) comprises a flexible belt (36). A first end part of the flexible belt (36) is connected on a reciprocating drive shaft (22) and a second end part is connected on a saw blade (26). In order to tightly connect the two ends of the flexible belt, the first end part of the flexible belt (36) is connected on a first chuck (40) in a self locking way and the second end part is also connected on a second chuck (42) in a self locking way.

Description

Bow saw

Technical field

The present invention relates to a kind of bow saw novel, improvement, specifically relate to a kind of bow saw that drives and adopt flexible band by motor.

Background technology

Typical bow saw comprises: have the main body of handle and U type framework, and U type framework has near-end and far-end and the opening between two ends; The motor that generation rotatablely moves, and this motor is connected on the main body; Reciprocator is converted into the reciprocating motion of reciprocal driving shaft in order to rotatablely moving; Saw blade with near-end and far-end, and this near-end is connected on the reciprocal driving shaft; Be connected several rollers in the U type framework; And flexible band, its first end is connected on the reciprocal driving shaft, and mid portion is led by roller, and second end then is connected on the far-end of saw blade, and the near-end of this saw blade is promoted by reciprocal driving shaft, and far-end is spurred by the flexibility band.Above-mentioned bow saw is used by utility power or powered battery usually.

Bow saw described here (hack saw) comprises various reciprocating motion class saws, as fret saw (scrollsaw), bow saw (coping saw) and bow saw.

Foregoing bow saw discloses in United States Patent (USP) bulletin US5924209A, and another kind of similarly bow saw also discloses in PCT patent application WO88/09249A1 to some extent.

As everyone knows, bow saw has been used flexible band, or rather, is a kind of metal steel band, drives saw blade by it and moves forward and backward, thereby save manual operation.Two free ends of described flexible band generally are by clamping device, are fixed on the saw blade as screw or clamp.

At present, the designer trends of bow saw are to adopt lightweight material.Can save the energy like this, and reduce vibration, and higher reciprocal speed can be provided, for the remarkable influence of having increased work efficiency.And, the steel band that is adopted also adopts light-duty metal material, and size is less, and therefore, it is flexibility and stable preferable just to require steel band to be necessary for, also required reliable connected mode for steel band and the chuck that grips steel band, in other words, promptly because the thickness of strips that adopts only is 0.5 millimeter or littler, thereby require steel band, steel band can not rupture easily with being connected of chuck, and in the connected mode of currently used routine, as screw or anchor clamps and be not suitable for using.

Summary of the invention

One of purpose of the present invention is to provide a kind of bow saw, and two free ends of the flexibility band that is adopted in this bow saw are easy fracture not.

Another object of the present invention is to provide a kind of bow saw, and the free end of the flexibility band that this bow saw adopted is connected on the related components in simple mode.

Another object of the present invention is to provide a kind of bow saw, and this hack saw blade moves reciprocatingly in reliable mode.

Another object of the present invention is to provide a kind of bow saw, and the component structural of this bow saw is simple.

Disclosed bow saw also comprises except that the feature that comprises the aforementioned typical bow saw [0011]Disclosed bow saw also comprises except that the feature that comprises the aforementioned typical bow saw: first and second chucks; The first end of flexible band is connected on first chuck in the mode of self-locking, and the second end is connected on second chuck in the mode of self-locking; First chuck also is connected on the reciprocal driving shaft and moves back and forth thereupon; Second chuck connects with respect to the activity of U type framework.

Adopt such design, the probability that fracture takes place flexible band will reduce, and therefore, can increase the pulling force of flexible band effectively and promote reciprocating speed.

Preferably, be connected on the chuck in the mode of twining, can realize the function of self-locking by both ends with the flexibility band.The number of times that twines is at least twice, is three times more suitably.

For the end that keeps flexible band is connected with the firm of chuck, the present invention has adopted such mode, and promptly this first chuck comprises first groove, and it accommodates first end of this flexibility band, and this second chuck comprises second groove, and it accommodates second end of this flexibility band.Wherein, first and/or second groove has two side portions, and wherein a part exceeds with respect to another part, can improve the firm degree of connection like this.

All adopt identical structure as two chucks, and can exchange use, then can reduce production costs effectively.

This first and/or second chuck is provided with circular distal.More precisely, each chuck can be set to half round post, and mid portion becomes cube.This first and/or second chuck can be by the material of lightweight, and especially the light metal material is made.

The present invention also comprises first sleeve pipe, and it is fixedly connected on the main body, and second sleeve pipe, also be fixedly connected on the main body, and first chuck slidably is arranged in first sleeve pipe, and second chuck is slidably disposed in second sleeve pipe.

The present invention can also comprise first sleeve pipe with first passage, and it is fixedly connected on the main body; Be housed in the first piston in the first passage slidably, this first piston has first end and the second relative end; Be provided with first cavity in first end of first piston, accommodate first chuck that is fastenedly connected in wherein in this first cavity; Be provided with first jockey in second end of first piston, to connect the near-end of saw blade.

The free end of this reciprocal driving shaft forms around portion, with clamping first chuck and be thus connected first chuck on reciprocal driving shaft.

Similarly, for connecting second chuck, the present invention also comprises second sleeve pipe with second channel, and it is fixedly connected on the main body; Be housed in second piston in the second channel slidably, this second piston has first terminal and second end relatively; Be provided with second cavity in first end of second piston, contain second chuck that is fastenedly connected in wherein in this second cavity; Be provided with second jockey in second end of second piston, to connect the remote point of saw blade.

The cross section of first and/or second piston is a rectangle, and first and/or the cross section of second channel also be rectangle.

First passage in first sleeve pipe has relative two side, and has the chute of longitudinally on each sidewall, and to accommodate the slide bar that is positioned at first piston, this chute is formed with the slip of retainer with the restriction first piston.

Second channel in second sleeve pipe has relative two side, and has the chute of longitudinally on each sidewall, and to accommodate the slide bar that is positioned at second piston, this chute is formed with retainer to limit the slip of second piston.

This flexibility band is made by the light metal material, as the 11R51 structural section.The thickness of this flexibility band is not more than 0.5 millimeter, and 0.2 millimeter more precisely, such flexibility band also meets the demand of power bow saw.

This flexibility band is made of some wires that independently, are arranged in rubber or the plastic layer.

The quantity of roller is decided according to the power demand of saw.Regulate roller for convenience, this first roller rotatably is connected on first sleeve pipe, and second roller rotatably is connected on second sleeve pipe.

A kind of chuck is also disclosed among the present invention, comprise cylindrical main body, and extension is provided with flat side's projection on the cylindrical body end faces of both sides, also comprise the connector that is used to accommodate this chuck among the present invention, be provided with a cavity in this connector, this cavity comprises the bottom surface, and is provided with the chute that is used for the insertion of described flat side's projection on the two side, and this chute comprises the rake of the bottom surface that is tilted to cavity.

Below in conjunction with drawings and the specific embodiments the present invention is described in further detail.

Fig. 1 is the schematic diagram of bow saw of the present invention;

Fig. 2 only shows some rollers, flexible band, saw blade and chuck for the part schematic diagram of bow saw of the present invention among the figure;

Fig. 3 is the stereogram of chuck;

Fig. 4 is chuck and the flexible connection diagram of being with;

Fig. 5 is that first chuck is connected the schematic perspective view on the first piston;

Fig. 6 is that first chuck is connected the vertical view on the first piston and first sleeve pipe;

Fig. 7 is the side view of first sleeve pipe;

Fig. 8 is the guiding schematic diagram of flexible band on roller;

The schematic diagram of the flexibility band that Fig. 9 is adopted for the another kind of embodiment of the present invention;

Figure 10 is that second chuck is connected the schematic perspective view on second piston;

Figure 11 is that second chuck is connected the vertical view on second piston and second sleeve pipe;

Figure 12 is the side view of second sleeve pipe;

Figure 13 is the side view of another embodiment of chuck among the present invention;

Figure 14 is the vertical view of another embodiment of chuck among the present invention;

Figure 15 is the A-A view of Figure 14;

Figure 16 is the B-B view of Figure 14,

Wherein, the related elements reference numeral is listed as follows:

The 2-bow saw; The 4-main body; The 6-handle; 8-U type framework; The near-end of 10-U type framework; The far-end of 12-U type framework; The 14-opening; The 16-motor; The 18-power switch; The 20-gear train; The reciprocal driving shaft of 22-; 24-reciprocator; The 26-saw blade; 27-first carriage; 28-first roller; 29-second carriage; 30-second roller; 32-the 3rd roller; The 33-knob; 34-the 4th roller; The flexible band of 36-; The 38-double-head arrow; 40-first chuck; 42-second chuck; 44-first groove; The 46-bottom; The 48-fixing hole; The 49-straight pin; The 50-double-head arrow; The 52-first piston; The 54-first saw blade connecting portion; 56-first cavity; The 58-connecting hole; The 59-connecting rod; The 60-hole; The 62-slide bar; 64-first sleeve pipe; 66-first rectangular channel; The 68-connecting rod; The 70-fixed bar; The 72-chute; 74-first retainer; 76-second retainer; 78-is around portion; The 80-lateral margin; The 82-lateral margin; The 84-wire; 86-rubber or plastic layer; 52B-second piston; The 54B-second saw blade connecting portion; 56B-second cavity; The 58B-connecting hole; The 59B-connecting rod; The 60B-hole; The 62B-slide bar; 64B-second sleeve pipe; 66B-second rectangular channel; The 68B-connecting rod; The 70B-fixed bar; The 72B-chute; 74B-first retainer; 76B-second retainer; The 100-chuck; The 102-main body; The flat side's projection of 104-; The 106-connector; The 108-cavity; The 110-bottom surface; The 112-chute; The 114-rake.

The specific embodiment

See also Fig. 1, a kind of bow saw 2 comprises main casing or main body 4, and this main body 4 includes handle 6 and U type framework 8.This U type framework 8 has near-end 10 and far-end 12 with respect to handle 6, and the opening between two ends 14.In the inside of U type framework 8,, electro-motor 16 is installed near the position of near-end 10.In the inside of handle 6, be provided with battery (figure does not show).Is connected with cable (figure does not show) between battery and the electro-motor 16, and powers to electro-motor 16 by power switch 18 control batteries.The motor shaft of this electro-motor 16 rotatablely moves in order to generation, and in the embodiment shown in fig. 1, this motor shaft is vertical the setting.

Described rotatablely moving is converted into reciprocating motion on the horizontal direction by gear train 20, and producing reciprocating is reciprocal driving shaft 22 in the reciprocator 24.Be provided with saw blade 26 in opening 14, this saw blade 26 also comprises a near-end and a far-end.See also Fig. 7, the free end of this reciprocal driving shaft 22 is connected on the near-end of saw blade 26 by first carriage 27 (comprising first piston 52), and the far-end of saw blade 26 then is connected second carriage 29 (comprising the second piston 52B) on the far-end 12 that is positioned at U type framework 8.Need to prove that as can see from Figure 1,

carriage

27 and 29 has identical structure.

Several balls bearing, roller or

roller

28,30,32,34 distribute around U type framework 8 and are provided with and can freely rotate on its position.See also the preferred embodiment of the present invention that Fig. 8 provides, flexibility is with 36 to be led by roller 28-34.Please further consult Fig. 2 to Fig. 7, this flexibility is connected on the reciprocal driving shaft 22 with 36 first end, and the second end then is connected on the far-end of saw blade 26, and this flexibility is led by four rolling 28-34 with 36 mid portion.Wherein, first and

second rollers

28,30 are connected on first and

second carriages

27,29, and the 3rd roller 32 is the part of tension adjusting device, and the knob 33 of described tension adjusting device can tighten or loosen flexibility and be with 36.

The reciprocating motion of this saw blade 26 is shown in the double-head arrow among Fig. 1 38, and the process that moves back and forth generation is as follows: after motor 16 energisings, back and forth driving shaft 22 will begin to move to right-hand, thereby the near-end of saw blade 26 also will be pushed along same direction.Simultaneously, be with 36 by flexibility, the far-end of saw blade 26 also will be pulled.If back and forth driving shaft 22 shrinks back left subsequently, then the near-end of saw blade 26 also will be pulled, and then flexible far-end with 36 also will be pulled, and so just can make flexibility be with 36 to turn back to initial position.Above-mentioned motion process can be seen in Fig. 2.

Please continue to consult Fig. 2, this first carriage 27 comprises first chuck 40, and this second carriage 29 comprises second chuck 42 with spline structure.Described flexibility is connected on first chuck 40 with 36 the first end mode with self-locking, the second end is connected on second chuck 42 in the mode of self-locking, and, these two free ends twine first,

second chuck

40,42 3 circles respectively, thereby be with 36 when pulled when flexibility, flexibility is with 36 can further tighten with respect to

chuck

40,42.

Subsequently clearly, first chuck 40 is connected on the reciprocal driving shaft 22 and moves back and forth to produce, and second chuck 42 produces with respect to U type framework 8 and slides or reciprocating motion.

This flexibility is with 36 can adopt the 11R51 structural section, and its thickness is not more than 0.2 millimeter, and for example 0.13 millimeter, and width is 8 millimeters.

Because first,

second chuck

40,42 has identical construction, only first chuck 40 is described here, sees also Fig. 3 and Fig. 4, first chuck 40 has microscler main body, and this body weight is less, can be that aluminium or plastic cement material constitute.The length L of this first chuck 40 is 15 millimeters, and height H is 8 millimeters, along its longitudinal cutting be provided with first groove 44, in this first groove 44, contain flexibility with 36 first end.This first chuck 40 is divided into left and right sides two parts by first groove 44, and right-hand component exceeds a segment distance with respect to left-hand component.This first chuck 40 has circular end, and or rather, this first chuck 40 has semi-cylindrical outline, and mid portion then forms cube.The bottom 46 of this first chuck 40 is the plane, and on the side end face, each limit that is positioned at first groove 44 is equipped with a fixing hole 48.See also Fig. 4, double-head arrow 50 indicates the reciprocating motion track of this first chuck 40.

Fig. 5 has disclosed the part of first carriage 27.Here reciprocal driving shaft 22 can't be demonstrated, but the rectangle cross section of first piston 52 can be clearly demonstrated.This first piston 52 comprises first end and the second relative end, and second end extends to the first saw blade connecting portion 54, wherein, is provided with first cavity 56 in first end.Accommodate first chuck 40 that is fastenedly connected in wherein in this first cavity 56, and be inserted in the fixing hole 48, and first chuck 40 is fixed in first cavity 56 by straight pin 49 (shown in Fig. 6).Thereby this first chuck 40 also can move reciprocatingly with first piston 52.

This first piston 52 can be made by light-duty solid metal material, as aluminium, and, can also form a firm top layer by the mode that applies.

The first saw blade jockey 54 comprises connecting hole 58, be used to insert a less screw or round bar 59 (as shown in Figure 6), by

such jockey

54,59, the near-end of saw blade 26 will be connected on the first piston 52 securely, and, the solid part of first piston 52 also comprises a hole 60 along its longitudinally horizontally set, is used to accommodate a slide bar 62, as shown in Figure 5.The length of slide bar 62 is greater than the length in hole 60, thereby can make slide bar 62 wear the both ends of the surface that extend in first piston 52, and forms stop device with stop first sleeve pipe 64.

See also Fig. 6 to Fig. 7, the center of this first sleeve pipe 64 is formed with first rectangular channel 66, and by pin 68 this first sleeve pipe 64 is fixed in the main body 4.This first piston 52 is housed in this first rectangular channel 66 slidably, and this flexibility is with 36 also partly to extend out (as shown in Figure 6) in this first rectangular channel 66.A columniform fixed bar 70 also is provided here, has been used to support first roller 28.

It should be noted that first roller 28 is partly to be arranged in first sleeve pipe 64.This first roller 28 is supported on the end of this first rectangular channel 66 with being rotated.

According to Fig. 6 and shown in Figure 7, slide bar 62 is slidably disposed in the chute 72 with respect to first rectangular channel 66, is formed with the slip that first retainer 74 and second retainer 76 are used to limit first piston 52 in this chute 72.

According to shown in Figure 7, back and forth the free end of driving shaft 22 is formed with around portion 78, with clamping first chuck 40, thereby first chuck 40 is thus connected on reciprocal driving shaft 22.

As shown in Figure 8, be another embodiment of the present invention, wherein, first roller 28 comprises that two lateral margins that exceed

roller

80,82 are with 36 with the flexibility that leads safely.

As shown in Figure 9, be another embodiment of the present invention, wherein, flexibility is made of wire 84 abreast some and that be arranged in rubber or the plastic layer 86 with 36.

See also Figure 10 to Figure 12, disclosed second carriage 29 and the second piston 52B.This second piston 52B comprises first end and the second relative end, and second end extends to the second saw blade connecting portion 54B, wherein, is provided with the second cavity 56B in first end.Accommodate second chuck 42 that is fastenedly connected in wherein in this second cavity 56B, and be inserted in the fixing hole 48, and second chuck 42 is fixed among the second cavity 56B by straight pin 49.Thereby this second chuck 42 also can move reciprocatingly with the second piston 52B.

This second piston 52B can be made by light-duty solid metal material, as aluminium, and, can also form a firm top layer by the mode that applies.

The second saw blade jockey 54B comprises connecting hole 58B, be used to insert a less screw or round bar 59B, by such jockey 54B, 59B, the far-end of saw blade 26 will be connected on the second piston 52B securely, and, the solid part of the second piston 52B also comprises a hole 60B along its longitudinally horizontally set, is used to accommodate a slide bar 62B, as shown in Figure 10.The length of slide bar 62B is greater than the length of hole 60B, thereby can make slide bar 62B wear the both ends of the surface that extend in the second piston 52B, and forms stop device with the stop second sleeve pipe 64B.This second sleeve pipe 64B is as shown in Figure 11 to Figure 12.

See also Figure 11 to Figure 12, the center of this second sleeve pipe 64B is formed with the second rectangular channel 66B, and by pin 68B this second sleeve pipe 64B is fixed in the main body 4.This second piston 52B is housed among this second rectangular channel 66B slidably, and this flexibility is with 36 also partly to extend out (as shown in figure 11) in this second rectangular channel 66B.A columniform fixed bar 70B also is provided here, has been used to support second roller 30.

It should be noted that second roller 30 is partly to be arranged among the second sleeve pipe 64B.This second roller 30 is supported on the end of this second rectangular channel 66B with being rotated.

According to Figure 11 and shown in Figure 12, slide bar 62B is slidably disposed among the chute 72B with respect to the second rectangular channel 66B, is formed with the slip that the first retainer 74B and the second retainer 76B are used to limit the second piston 52B among this chute 72B.

See also Figure 13 to Figure 16, the invention also discloses a kind of chuck 100 that adopts the self-locking mode, this chuck comprises cylindrical body 102, and extension is provided with flat side's projection 104 on main body 102 end faces of both sides.This chuck 100 can be housed in respectively in the connector 106 in first carriage 27 and second carriage 29, be provided with a cavity 108 in the connector 106 here, this cavity 108 comprises bottom surface 110, and be provided with the chute 112 of flat side's projection 104 insertions that are used for chuck 100 on the two side, this chute 112 comprises the rake 114 of the bottom surface 110 that is tilted to cavity 108.

During use, flexibility is with 36 more than cylindrical body 102 at least two circle, flexibility can adopt as the mode among the embodiment one with 36 end, and end is inserted in the groove on the main body 102.Then, sliding in chute 112 by flat side projection 104 can be housed in this chuck 100 in the cavity 108 in this connector 106, and at this moment, the flexibility that is centered around on the main body 102 will be conflicted on the bottom surface 110 of cavity 108 with 36, but be not to be tensioning state.Therefore, also need further make flexibility be with 36 tensionings, thereby pulling chuck 100 to continue to produce mobile trend to the bottom surface of cavity 108, so far, and reaches a kind of state that clamps flexible band by regulating flexibility with 36 tensioning apparatus.Here adopted the self-locking mode identical as embodiment one, promptly when flexibility was with 36 to be tensioned, chuck 100 can be with flexibility 36 to clamp all the more, thereby avoided flexibility to break away from from chuck 100 with 36 free end or rupture.

Figure 13 to Figure 16 only shows the chuck 100 of the far-end 12 of the U type framework that is positioned at bow saw 2, and its chuck structure of near-end 10 of U type framework that is positioned at bow saw 2 is identical therewith, and difference only is that connector 106 also is connected with reciprocal driving shaft 22.

Claims

1. bow saw, comprising: main body, this main body comprise handle and U type framework, this U type framework has near-end and far-end and the opening between two ends; Motor can produce and rotatablely moves, and this motor is installed on the main body; Reciprocator can be converted into the reciprocating motion of reciprocal driving shaft with described rotatablely moving; Saw blade has near-end and far-end, and near-end is connected on the reciprocal driving shaft; Several rollers are installed on the U type framework; Flexible band, its first end is connected on the reciprocal driving shaft, and mid portion is led by roller, and the second end is connected the far-end of saw blade; The near-end of this saw blade is promoted by one of them of reciprocal driving shaft and flexible band, and far-end is by flexibility band and back and forth another pulling of driving shaft, and it is characterized in that: this bow saw also comprises first, second chuck; The first end of this flexibility band is connected on first chuck in the mode of self-locking, and the second end is connected on second chuck in the mode of self-locking; This first chuck is connected on the reciprocal driving shaft and moves back and forth thereupon; This second chuck then connects with respect to the activity of U type framework.

2. bow saw as claimed in claim 1 is characterized in that: first and/or the second end of this flexibility band is wrapped in respectively on first and/or second chuck.

3. bow saw as claimed in claim 2 is characterized in that: this first chuck comprises first groove, and accommodating first end of this flexibility band, and/or this second chuck comprises second groove, to accommodate second end of this flexibility band.

4. bow saw as claimed in claim 3 is characterized in that: this first and/or second chuck is provided with circular distal.

5. bow saw as claimed in claim 4 is characterized in that: this first and/or second groove has two side portions, and wherein a part exceeds with respect to another part.

6. as arbitrary described bow saw in the claim 1 to 5, it is characterized in that: also comprise first sleeve pipe, it is fixedly connected on the main body, and second sleeve pipe, it is fixedly connected on the main body, and first chuck slidably is arranged in first sleeve pipe, and second chuck is slidably disposed in second sleeve pipe.

7. as arbitrary described bow saw in the claim 1 to 5, it is characterized in that: also comprise first sleeve pipe with first passage, it is fixedly connected on the main body; Be housed in slidably by the first piston in the passage, this first piston has first end and the second relative end; Be provided with first cavity in first end of first piston, contain first chuck that is fastenedly connected in wherein in this first cavity; Be provided with first jockey in second end of first piston, to connect the near-end of saw blade.

8. bow saw as claimed in claim 7 is characterized in that: the free end of this reciprocal driving shaft forms around portion, with clamping first chuck and be thus connected first chuck on reciprocal driving shaft.

9. bow saw as claimed in claim 8 is characterized in that: also comprise: have second sleeve pipe of second channel, it is fixedly connected on the main body; Be housed in second piston in the second channel slidably, this second piston has first end and the second relative end; Be provided with second cavity in first end of second piston, contain second chuck that is fastenedly connected in wherein in this second cavity; Be provided with second jockey in second end of second piston, to connect the far-end of saw blade.

10. bow saw as claimed in claim 9 is characterized in that: the cross section of first and/or second piston is a rectangle, and first and/or the cross section of second channel also be rectangle.

11. bow saw as claimed in claim 10 is characterized in that: first and second chucks have flat bottom, so that it inserts first and second pistons respectively.

12. bow saw as claimed in claim 11, it is characterized in that: the first passage in first sleeve pipe has relative two side, and have the chute of longitudinally on each sidewall, to accommodate the slide bar that is positioned at first piston, this chute is formed with the slip of retainer with the restriction first piston.

13. bow saw as claimed in claim 12, it is characterized in that: the second channel in second sleeve pipe has relative two side, and have the chute of longitudinally on each sidewall, to accommodate the slide bar that is positioned at second piston, this chute is formed with retainer to limit the slip of second piston.

14. bow saw as claimed in claim 1 is characterized in that: this flexibility band is made by the light metal material.

15. bow saw as claimed in claim 14 is characterized in that: this flexibility band is made of some wires that independently, are arranged in rubber or the plastic layer.

16. bow saw as claimed in claim 15 is characterized in that: the thickness of this flexibility band is not more than 0.5 millimeter.

17. bow saw as claimed in claim 15 is characterized in that: the thickness of this flexibility band is not more than 0.2 millimeter.

18. as claim 16 or 17 described bow saws, it is characterized in that: this first roller rotatably is connected on first sleeve pipe, and second roller rotatably is connected on second sleeve pipe.

19. bow saw as claimed in claim 1 is characterized in that: this first and/or second chuck is made by the light metal material.

20. bow saw as claimed in claim 1 is characterized in that: this first and/or second chuck comprises cylindrical main body, and extension is provided with flat side's projection on the cylindrical body end faces of both sides.

21. bow saw as claimed in claim 20, it is characterized in that: also comprise the connector that is used to accommodate first and/or second chuck, be provided with a cavity in this connector, this cavity comprises the bottom surface, and be provided with the chute that is used for the insertion of described flat side's projection on the two side, this chute comprises the rake of the bottom surface that is tilted to cavity.