CN207890965U - A kind of electric shear V shape belt elevator - Google Patents

Abstract

The utility model discloses a kind of electric shear V shape belt elevators.Belt tension assembly keeps belt tension degree adjustable, and the setting of elastic element can make multiple straps synchronous tension, keep its stress more balanced, prolong the service life.Guiding axis and X-type the support arm design of belt drive keep elevator operation more steady, and when belt fracture, intermediate guiding axis can play the role of mechanical protection and keep bracket decline very slow, ensure safety in production.

Description

A kind of electric shear V shape belt elevator

Technical field

The utility model relates generally to a kind of elevator, and in particular to a kind of scissors V shape belt elevator.

Background technology

Scissors fork lifter is common elevation and subsidence mechanical in industrial production.Traditional scissors V shape hydraulic elevator hydraulic pressure Oily easily leakage, is not suitable for requiring production environment high workshop section, and due to such elevator receive need after signal it is first right Hydraulic cylinder filling liquid pressure oil, causes elevator response speed slow.Therefore, in order to promote working efficiency and ensure production environment, tradition Hydraulic elevator gradually replaced by electric shear V shape belt elevator.The basic structure of scissors V shape belt elevator with Scissors V shape hydraulic elevator has no significant difference, will only be connected to the driving unit between two scissors yokes of composition X-type Belt is changed by hydraulic stem, makes novel elevator that there is fast response time, operate steadily, environmental-friendly advantage.However it is existing Some scissors V shape belt elevators are the simple phase of driving shaft for being driven the sliding end of scissors yoke with engine with belt Even, belt can be around on driving shaft or unclamp and realize from driving shaft the lifting of elevator when engine being made to run.It is such to cut The following problem of forks and knives belt elevator generally existing：1) two root skins band force unbalance, easily makes rig bracket slant, severe patient Belt service life can be reduced, or belt is caused to be broken suddenly；If 2) belt fracture, object i.e. follow bracket to fall rapidly and can Accident can occur, can not ensure safety；3) whereabouts may occur accident or cause bracket suddenly due to gravity when power-off suddenly Engine damages.

Utility model content

The utility model provides a kind of electric shear V shape belt elevator, and increased belt driving structure makes elevator Stable smoothness has no abnormal sound.

To realize that this purpose, the utility model use the following technical solution：

A kind of electric shear V shape belt elevator, including chassis, bracket, scissors fork assembly, engine and driving shaft, cut Knife and fork assembly is between chassis and bracket, and engine is mounted on by pedestal on chassis, and driving shaft is mounted on by connector On chassis, the power output end of driving shaft and engine forms be connected by power, it is characterised in that：The scissors fork assembly includes two To symmetrical scissors yoke, each pair of scissors yoke is made of the lifting arm to form X-shaped structure that is hinged in the middle part of in the of two, Upper free end and bracket are hinged one of in each pair of scissors yoke, free end and support on another in each pair of scissors yoke Frame is slidably connected, and lower free end and chassis are hinged one of in each pair of scissors yoke, another in each pair of scissors yoke Lower free end is slidably connected with chassis, the hinged end and lower free end of upper free end and bracket and chassis in each pair of scissors yoke Hinged end is in the same side and forms hinged end side, the end and lower hanging of being slidably connected of upper free end and bracket in each pair of scissors yoke End and the end that is slidably connected of chassis form sliding end side in the same side；Setting can drive scissors to pitch between two pairs of scissors yokes Make the belt drive slided back and forth on chassis and bracket respectively in the sliding end side of arm.

Compared with the prior art, the utility model has the advantages that：

Belt drive is set between two pairs of scissors yokes rather than belt is simply fixed on scissors yoke End side is slided, this so that scissors yoke is more balanced by stress when driving opening and closing, to make the lifting action of elevator run more Stablize smooth.

Part is illustrated to embody by the further advantage, target and feature of the utility model by following, and part will also pass through Research and practice of the invention are understood by the person skilled in the art.

Description of the drawings

Fig. 1 is a kind of stereoscopic schematic diagram of electric shear V shape belt elevator；

Fig. 2 is scissors fork and belt drive combination diagram；

Fig. 3 is that scissors pitches structural schematic diagram；

Fig. 4 is sliding groove structure schematic diagram；

Fig. 5 is belt drive schematic diagram；

Fig. 6 is belt pulley, fixed seat, mobile foundation and guide post structure schematic diagram；

Fig. 7 is belt wrapping system schematic diagram；

Fig. 8 is belt tension assembly structure schematic diagram.

Specific implementation mode

In order to make, technological means of the utility model, creation characteristic, reached purpose and effect are more clear and are easy to Understand, the utility model is further elaborated with reference to the accompanying drawings and detailed description：

In conjunction with Fig. 1-4, the utility model proposes a kind of electric shear V shape belt elevators, including chassis 100, bracket 200, scissors fork assembly 300, engine 470 and driving shaft 430, scissors pitch assembly 300 between chassis 100 and bracket 200, Engine 470 is mounted on by pedestal on chassis 100, and driving shaft 430 is mounted on by connector 480 on chassis, driving shaft 430 Be connected by power is formed with the power output end of engine 470, the scissors fork assembly 300 includes two pairs of symmetrical scissors forks Arm 310, each pair of scissors yoke 310 are made of the lifting arm to form X-shaped structure that is hinged in the middle part of in the of two, each pair of scissors yoke Upper free end and bracket 200 are hinged one of in 310, free end and bracket on another in each pair of scissors yoke 310 200 are slidably connected, and lower free end and chassis 100 are hinged one of in each pair of scissors yoke 310, each pair of scissors yoke 310 In another lower free end be slidably connected with chassis 100, being hinged for free end and bracket 200 is gone up in each pair of scissors yoke 310 End and the hinged end of lower free end and chassis 100 are in the same side and form hinged end side, and free end is gone up in each pair of scissors yoke 310 With the end that is slidably connected of be slidably connected end and lower free end and the chassis 100 of bracket 200 sliding end side is formed in the same side； Setting can drive the sliding end side of scissors yoke 310 to make respectively on bracket 200 in chassis 100 between two pairs of scissors yokes 310 The belt drive 400 slided back and forth.

In use, engine 470 drives driving shaft 430 to rotate, the belt being fixed on driving shaft 430 460 is made to be wound on master On moving axis 430, belt 460 is gradually tensioned, and engine 470 is rotated further, and belt drive 400 makes to cut under the action of belt Knife and fork arm 310 opens, and bracket 200 is elevated and completes lifting action；When engine 470 drives driving shaft 430 to rotate backward, Belt loosens, and bracket 200 is influenced by gravity and fallen, but is loosened rate limitation by belt, and scissors fork drives in belt to be filled Setting makes bracket falling speed stablize gently under 400 restriction effect.

Belt drive is set between two pairs of scissors yokes rather than belt is simply fixed on scissors yoke End side is slided, this so that scissors yoke is more balanced by stress when driving opening and closing, smooth to make elevator operation more stablize.

Preferably, in conjunction with Fig. 5-7, the belt drive 400 includes guiding axis 450, belt 460, fixing end group Part and mobile terminal component, wherein fixing end component includes fixed seat 410 and fixed end belt pulley 411, and fixed seat 410, which is fixed on, to be led To one end of axis 450, fixed end belt pulley 411 is mounted in fixed seat 410, and two group of first support is hinged in fixed seat 410 Arm 441, two group of first support arm 441 are located at the both sides of guiding axis 450；It is provided with to be located in the bottom of fixed seat 410 and lead To the belt tension assembly 500 of 450 lower section of axis；

Mobile terminal component includes mobile foundation 420, moved end belt pulley 421, and mobile foundation 420 is solid in being slidably mounted on On the guiding axis 450 in the front of reservation 410, moved end belt pulley 421 be mounted on mobile foundation 420 and with 411 phase of fixed end belt pulley It is right, two group of second support arm 442 is hinged on mobile foundation 420, two group of second support arm 442 is located at guiding axis 450 Both sides；

First support arm 441 is opposite with the cantilever end of the second support arm 442, and one end of belt 460 is fixed on driving shaft 430 On, the other end of belt 460 is fixed on belt tension assembly 500 by fixed end belt pulley 411 and after bypassing moved end belt pulley 421 On.

When the startup of engine 470 makes belt gradually be wrapped on driving shaft 430, belt tension assembly 500 by opening in advance After dynamic state, engine 470 remains in operation, make mobile foundation 420 under the pulling function of belt 460 along guiding axis 450 to solid It moves in 410 direction of reservation so that the X of the first support arm 441 and the second support arm 442 opens, and is connected on component to be supported Two cantilever ends distance increases.

The setting of guiding axis 450 limits the moving direction of mobile foundation 420, keeps elevator operation more stable, also, work as When belt 460 is surprisingly broken, guiding axis 450 can make 200 decrease speed of bracket very slow as mechanical protection, avoid bracket 200 prominent It so falls and accident occurs；The setting of moved end belt pulley 421 and fixed end belt pulley 411 keeps elevator operation more smooth and has no abnormal sound, Using the belt tension assembly 500 make multigroup belt drive 400 can synchronous averaging synchronous operation, 460 stress of each belt Uniformly, the service life of belt 460 is extended；And engine 470 has the function of the automatic locking of power-off, this to work as engine Make entire elevator emergency braking when 470 power-off suddenly and avoid causing danger.

Preferably, every group of first support arm 441 and every group of second support arm 442 are connected by upper drive link and lower driving Bar is constituted, wherein one end of the upper drive link in the first support arm 441 is hinged on 410 side surface upper part of fixed seat, and lower driving connects Bar is hinged on 410 side lower of fixed seat, and the inclined downward of the other end to the fixed seat 410 of upper drive link is hanging, lower driving The inclined upward of the other end of connecting rod to fixed seat 410 is hanging, and upper drive link is located at the inside of lower drive link, makes driving Connecting rod intersects to form X-shaped with lower drive link；

One end of upper drive link in second support arm 442 is hinged on 420 side surface upper part of mobile foundation, the second support arm Lower drive link in 442 is hinged on 420 side lower of mobile foundation, and the other end of upper drive link is to mobile foundation 420 Inclined downward is hanging, and the inclined upward of the other end to the mobile foundation 420 of lower drive link is hanging, and upper drive link is located at lower drive The outside of dynamic connecting rod, makes drive link intersect to form X-shaped with lower drive link.

Being had using this scheme is made mechanism to be supported be more uniformly stressed and extends its service life, and elevator is made to transport Capable more stably benefit.Also, this mode is a kind of explanation of preferred embodiments, and however, it is not limited to this.Implementing When the utility model, other suitable arrangements can be selected according to user's demand.It can also be arranged on guiding axis pair The locating part of mobile terminal component maximum movement position improves the reliability used to prevent mobile terminal component from being skidded off from guiding axis.

Preferably, it is provided with lower support shaft between the free end of the upper drive link in two group of first support arm 441 443, support shaft 444, upper support shaft 444 are provided between the free end of the lower drive link in two group of first support arm 441 Positioned at the top of guiding axis 450, lower support shaft 443 is located at the lower section of guiding axis 450；Upper drive in two group of second support arm 442 It is provided with lower support shaft 443 between the free end of dynamic connecting rod, support shaft 444 is provided between the free end of lower drive link, Upper support shaft 444 is located at the top of guiding axis 450, and lower support shaft 443 is located at the lower section of guiding axis 450.Had using this scheme There is the benefit for keeping support arm configuration more stable.Also, this mode is a kind of explanation of preferred embodiments, but not office It is limited to this.When implementing the utility model, other reinforcing modes can be selected according to user's demand.

Preferably, the fixed end belt pulley 411 and moved end belt pulley 421 are two groups, two groups of fixed end belt pulleys 411 and Moved end belt pulley 421 is located at the both sides of guiding axis 450；Every group of fixed end belt pulley 411 is by two skins in front and back arrangement Belt wheel is constituted；The lower section of every group of fixed end belt pulley 411 is respectively and fixedly provided with belt tension assembly 500, and every group of moved end belt pulley 421 is by being in Two belt pulleys arranged up and down are constituted.Using this scheme have make structure stress to be driven evenly, operation it is more stable Benefit.Also, this mode is a kind of explanation of preferred embodiments, and however, it is not limited to this.Implementing the utility model When, single group, three groups or more groups can be selected according to user's demand.

Preferably, in conjunction with Fig. 8, the belt tension assembly 500 includes belt fixed part and carrier interconnecting piece；

The belt fixed part includes backstand bottom plate 511, top board 512 and lower platen 513,512 He of the top board Lower platen 513 is removably installed on 511 two sides of backstand bottom plate and pre- between backstand bottom plate 511 respectively There are the gap passed through for belt 460, backstand bottom plate 511 extends outwardly away and offers through-hole on its extension, leads to Deflecting roller 514 for belt winding is installed in hole；

The carrier interconnecting piece includes connecting rod 521 for belt tension assembly to be installed on carrier and covers successively The first baffle ring 522, elastic element 523 and the second baffle ring 524, the connecting rod 521 being connected in connecting rod 521 are fixed on tensioning On seat 511 extension of bottom plate and on 511 extending direction of backstand bottom plate, first baffle ring, 522 and second baffle ring 524 divides It is not fixed on the both ends of elastic element 523, first baffle ring 522 is slidably connected with the connecting rod 521, second baffle ring 524 are fixedly connected with the connecting rod 521；It is arranged with position-limiting drum 525 outside the elastic element 523.

When this belt tension assembly 500 is installed on carrier, connecting rod 521 passes through the through-hole that carrier is reserved, belt solid Determine portion and carrier coupling part is distributed in the both sides of carrier mounting plate, the first baffle ring 522 is against in the plate face of carrier mounting plate, works as skin Band gradually tenses movement under power effect, and belt drives belt fixed part, connecting rod 521 and the second baffle ring 524 to move together, And so that the first baffle ring 522 is pressed in the plate face of carrier mounting plate, elastic element 523 is compressed, and the second baffle ring 524 gradually connects Nearly first baffle ring 522, distance is limited position 525 length of cylinder between final the two, and pre- starting process terminates, and belt 460 drives carrier It is mobile.

Such flexible belt tension assembly 500 is so that multigroup belt of electric shear V shape belt elevator drives 400 start-up courses of device are there are one buffer time, i.e., pre- starting process, this makes its multigroup belt drive can be with synchronization onwards Phenomena such as dynamic, synchronous whereabouts, multiple straps unbalance stress, bracket 200 slant when being not in startup, also extend belt 460 Service life.

Preferably, the connecting rod 521 is lead screw, is screw thread between second baffle ring 524 and the connecting rod 521 Connection.Make that the second baffle ring 524 and connecting rod can be adjusted according to the tightness of belt 460 in use using this scheme Relative position between 521 and be easily tensioned belt 460.Also, this mode is a kind of explanation of preferred embodiments, but simultaneously It is not limited to this.When implementing the utility model, the second baffle ring 524 and connecting rod can be made according to the selection of user's demand is other The adjustable connection type of relative position between 521.

Preferably, the elastic element 523 is spring, and the position-limiting drum 525 is hollow cylinder spring protecting sleeve.It is this In scheme, spring has the advantage that material is easy to get, is light-weight, elastic deformation range is big, therefore the present embodiment is chosen spring conduct and needed Elastic element 523, and position-limiting drum 525 chooses hollow cylinder spring protecting sleeve accordingly.Also, this mode is one kind The explanation of preferred embodiments, however, it is not limited to this.When implementing the utility model, other bullets can be selected according to user's demand Property element 523 and position-limiting drum 525.

Preferably, the wherein side upper ends Liang Ge and two lower ends of two pairs of scissors yokes 310 pass through branch respectively It supports crossbeam 330 to be connected, two upper ends of other side and two lower ends are also connected by support beam 330 respectively.Using this Scheme has the benefit for keeping the structure of scissors yoke 310 more stable.Also, this mode is a kind of preferred embodiments Illustrate, however, it is not limited to this.When implementing the utility model, other reinforcing modes can be selected according to user's demand.

Preferably, the chassis 100 is configured to rectangular frame with bracket 200, and is arranged in a pair of of long side There is the sliding slot 110 being slidably connected for scissors yoke 310, the sliding slot 110 is close to another described in place chassis 100 or bracket 200 The short side at end is arranged；The scissors yoke 310 is protected by the way that pulley 320 is arranged at 330 both ends of support beam with corresponding sliding slot 110 It holds and is slidably connected；The sliding slot 110 is provided at both ends with pulley column 111.Using this scheme, sliding slot 110 coordinates with pulley 320 So that scissors yoke 310 is slidably connected with bracket 200 and chassis 100 more smooth without hindrance, ensures that elevator operation is more stable.Sliding slot 320 column 111 of pulley of 110 both sides setting also limits 320 moving range of pulley, avoid the movement of pulley 320 transfinite and from cunning It is detached from and causes the accident in slot 110.Also, this mode is a kind of explanation of preferred embodiments, and however, it is not limited to this.Implementing When the utility model, other connection types can be selected according to user's demand.In addition, scissors yoke 310 and chassis 100 or support Can being hingedly hinged on short side for frame 200, can also be hinged in long side, it is only necessary to ensure that articulated shaft is mutually parallel with short side .

Further, the branch of the square tube shape for fixing switch bracket 603 is welded on the outside of the detent ends short side of bracket 200 Frame fixed frame 602；Engine 470 is fixed on scissors fork on ground on the outside of chassis hinged end, by sprocket wheel and passes through bearing holder (housing, cover) Interior driving shaft 430 connects, and the driving shaft 430 is rotatablely connected by bearing and bearing holder (housing, cover) 480, leads on the driving shaft 430 Crossing bolt fixation, there are two belt locking lids 481；Electrical holder 601 is fixed on the outside of chassis detent ends on ground, the switch Holder 603 is socketed in the bracket holder 602；Chassis short side is respectively fixed with support post 490 under two repairs.Bracket It is composed of angle steel and steel plate welding.Scissors yoke be the scissors yoke made of anti-twist single solid steel with beam welding and At.Engine is motor and is controlled by PLC, the driving shaft can be driven to move forward or backwards, and movement velocity is adjustable.Skin Band is automobile wire-core belt.

Claims (10)

1. a kind of electric shear V shape belt elevator, including chassis (100), bracket (200), scissors fork assembly (300), power Machine (470) and driving shaft (430), scissors fork assembly (300) are located between chassis (100) and bracket (200), engine (470) It is mounted on chassis (100) by pedestal, driving shaft (430) is mounted on by connector (480) on chassis, driving shaft (430) Be connected by power is formed with the power output end of engine (470), it is characterised in that：The scissors fork assembly (300) includes two pairs Symmetrical scissors yoke (310), each pair of scissors yoke (310) are hinged to form the liter of X-shaped structure by two middle parts It drops arm to constitute, upper free end and bracket (200) are hinged one of in each pair of scissors yoke (310), each pair of scissors yoke (310) free end is slidably connected with bracket (200) on another in, lower outstanding one of in each pair of scissors yoke (310) Dead end is hinged with chassis (100), another lower free end in each pair of scissors yoke (310) is slidably connected with chassis (100), often Upper free end in scissors yoke (310) is in the hinged end of bracket (200) and the hinged end of lower free end and chassis (100) The same side forms hinged end side, the end and lower hanging of being slidably connected of upper free end and bracket (200) in each pair of scissors yoke (310) End and the end that is slidably connected of chassis (100) form sliding end side in the same side；Energy is set between two pairs of scissors yokes (310) Make the belt slided back and forth driving on chassis (100) and bracket (200) respectively and fill in the sliding end side of driving scissors yoke (310) It sets (400).

2. electric shear V shape belt elevator as described in claim 1, it is characterised in that：The belt drive (400) include guiding axis (450), belt (460), fixing end component and mobile terminal component, wherein fixing end component includes fixing Seat (410) and fixed end belt pulley (411), fixed seat (410) are fixed on one end of guiding axis (450), fixed end belt pulley (411) peace In fixed seat (410), two group of first support arm (441), two group of first support arm are hinged in fixed seat (410) (441) both sides of guiding axis (450) are located at；It is provided with below guiding axis (450) in the bottom of fixed seat (410) Belt tension assembly (500)；

Mobile terminal component includes mobile foundation (420), moved end belt pulley (421), and mobile foundation (420) is in be slidably mounted on On guiding axis (450) in front of fixed seat (410), moved end belt pulley (421) be mounted on mobile foundation (420) on and with fixed end skin Belt wheel (411) relatively, is hinged with two group of second support arm (442), two group of second support arm (442) on mobile foundation (420) It is located at guiding axis (450) both sides；

First support arm (441) is opposite with the cantilever end of the second support arm (442), and one end of belt (460) is fixed on driving shaft (430) on, the other end of belt (460) is fixed on belt by fixed end belt pulley (411) and after bypassing moved end belt pulley (421) It is tensioned on assembly (500).

3. electric shear V shape belt elevator as claimed in claim 2, it is characterised in that：Every group of first support arm (441) And every group of second support arm (442) is made of upper drive link and lower drive link, wherein in the first support arm (441) One end of upper drive link is hinged on fixed seat (410) side surface upper part, and lower drive link is hinged under fixed seat (410) side The inclined downward in portion, the other end to the fixed seat (410) of upper drive link is hanging, and the other end of lower drive link is to fixed seat (410) inclined upward is hanging, and upper drive link is located at the inside of lower drive link, makes drive link and lower drive link phase Mutually intersect to form X-shaped；

One end of upper drive link in second support arm (442) is hinged on mobile foundation (420) side surface upper part, the second support arm (442) the lower drive link in is hinged on mobile foundation (420) side lower, and the other end of upper drive link is to mobile foundation (420) inclined downward is hanging, and the inclined upward of the other end to the mobile foundation (420) of lower drive link is hanging, and upper driving connects Bar is located at the outside of lower drive link, and drive link is made to intersect to form X-shaped with lower drive link.

4. electric shear V shape belt elevator as claimed in claim 3, it is characterised in that：Two group of first support arm (441) In upper drive link free end between be provided with lower support shaft (443), lower driving in two group of first support arm (441) connects Support shaft (444) is provided between the free end of bar, upper support shaft (444) is located at the top of guiding axis (450), lower support shaft (443) it is located at the lower section of guiding axis (450)；It is arranged between the free end of upper drive link in two group of second support arm (442) There is lower support shaft (443), support shaft (444) is provided between the free end of lower drive link, upper support shaft (444), which is located at, leads To the top of axis (450), lower support shaft (443) is located at the lower section of guiding axis (450).

5. the electric shear V shape belt elevator as described in claim 2,3 or 4, it is characterised in that：The fixed end belt pulley (411) and moved end belt pulley (421) is two groups, and two groups of fixed end belt pulleys (411) and moved end belt pulley (421) are located at and lead To the both sides of axis (450)；Every group of fixed end belt pulley (411) is constituted by two belt pulleys of front and back arrangement；Every group of fixed end skin Belt tension assembly (500) is respectively and fixedly provided with below belt wheel (411), every group of moved end belt pulley (421) is by two arranged up and down A belt pulley is constituted.

6. electric shear V shape belt elevator as claimed in claim 5, it is characterised in that：The belt tension assembly (500) include belt fixed part and carrier interconnecting piece；

The belt fixed part includes backstand bottom plate (511), top board (512) and lower platen (513), the top board (512) and lower platen (513) be removably installed on respectively backstand bottom plate (511) two sides and with backstand bottom plate (511) gap passed through for belt (460) is reserved between, backstand bottom plate (511) extends outwardly away and in its extension Through-hole is offered in portion, and the deflecting roller (514) for belt winding is installed in through-hole；

The carrier interconnecting piece includes connecting rod (521) for belt tension assembly to be installed on carrier and is socketed successively In the first baffle ring (522), elastic element (523) and the second baffle ring (524) in connecting rod (521), the connecting rod (521) is solid Due on backstand bottom plate (511) extension and on backstand bottom plate (511) extending direction, first baffle ring (522) The both ends of elastic element (523), first baffle ring (522) and the connecting rod are separately fixed at the second baffle ring (524) (521) it is slidably connected, second baffle ring (524) is fixedly connected with the connecting rod (521)；The elastic element (523) is outside It is arranged with position-limiting drum (525).

7. electric shear V shape belt elevator as claimed in claim 6, it is characterised in that：The connecting rod (521) is silk Bar is to be threadedly coupled between second baffle ring (524) and the connecting rod (521).

8. electric shear V shape belt elevator as claimed in claim 7, it is characterised in that：The elastic element (523) is Spring, the position-limiting drum (525) are hollow cylinder spring protecting sleeve.

9. electric shear V shape belt elevator as described in claim 1, it is characterised in that：Two pairs of scissors yokes (310) the wherein side upper ends Liang Ge and two lower ends is connected by support beam (330) respectively, two upper ends of other side And two lower ends are also connected by support beam (330) respectively.

10. a kind of electric shear V shape belt elevator as described in claim 1, it is characterised in that：The chassis (100) with Bracket (200) is configured to rectangular frame, and the cunning being slidably connected for scissors yoke (310) is disposed in a pair of of long side Slot (110), the sliding slot (110) is close to the setting of the short side of place chassis (100) or bracket (200) described other end；It is described to cut Knife and fork arm (310) is slidably connected by the way that pulley (320) is arranged at support beam (330) both ends with corresponding sliding slot (110) holding； The sliding slot (110) is provided at both ends with pulley column (111).