Summary of the invention
Because the above-mentioned defect of prior art, technical problem to be solved in the utility model is to provide a kind of slim reversible ratcheting tool, realizes using in narrow space and stable switching main axis direction.
For achieving the above object, the utility model provides a kind of slim reversible ratcheting tool, comprises operate portions and handle, and described operate portions comprises main shaft, and described main shaft is used for output torque and its axes normal in described handle, driving gear, driven gear, intermediate gear shaft and idler gear, described driving gear, driven gear and intermediate gear shaft are all set on described main shaft, the axis of described intermediate gear shaft and the axes normal of described main shaft, described idler gear is arranged on described intermediate gear shaft, and be engaged in transmission between described driving gear and described driven gear, wherein said handle drives described driving gear to rotate, a grip device is installed with outside described intermediate gear shaft, when gripping described grip device, rotate described handle when driving described driving gear to rotate, described driving gear drives described driven gear to reversely rotate by described idler gear, the first ratchet face rotated together with driving gear, and the second ratchet face rotated together with driven gear, the first pawl element and second pawl element of described main axis can be driven, wherein said first pawl element has the first ratchet and the second ratchet that optionally coordinate with described first ratchet face, wherein said first ratchet skids with described first ratchet face in a first direction, in a second direction then with described first ratchet face couple drive, described second ratchet in a first direction with described first ratchet face couple drive, then skid with described first ratchet face in a second direction, described second pawl element has the 3rd ratchet and the 4th ratchet that optionally coordinate with described second ratchet face, wherein said 3rd ratchet skids with described first ratchet face in a first direction, in a second direction then with described first ratchet face couple drive, described 4th ratchet in a first direction with described first ratchet face couple drive, then skid with described first ratchet face in a second direction, reversing switch, described first pawl element and described second pawl element can be arranged on the first state and the second state by described reversing switch, in said first condition, described first ratchet and described 3rd ratchet coordinate with described first ratchet face and the second ratchet face simultaneously respectively, in said second condition, described second ratchet and described 4th ratchet coordinate with described first ratchet face and the second ratchet face simultaneously respectively, described first direction is clockwise or counterclockwise, described second direction be with first party in the opposite direction, the thickness of described operate portions is less than or equal to 30mm.
In a further embodiment, the first pawl element and/or the second pawl element adopt high-strength material, and preferably, the material of employing is injection powder metallurgy.
In a further embodiment, the thickness of one of them pawl element is less than or equal to 6.5mm, the thickness of another pawl element is less than or equal to the thickness of this pawl element, identical with the thickness of pawl element with the thickness of the ratchet face of pawl element couple drive, the thickness of intermediate gear shaft is less than or equal to 8mm, and the modulus of idler gear is less than or equal to 1; Preferably, the thickness of the first pawl element is 5mm, and the thickness of the second pawl element is less than the thickness of the first pawl element, and the thickness of intermediate gear shaft is 6mm, and the modulus of idler gear is 0.6, and the thickness of operate portions is 25mm.
In a further embodiment, handle has toroidal head portion, and the first ratchet face is arranged on the inner ring of toroidal head portion.
In a further embodiment, the first ratchet face is arranged on the inner ring of driving gear.
In a further embodiment, the second ratchet face is arranged on the inner ring of driven gear.
In a further embodiment, grip device is gripper rings.
In a further embodiment, the first pawl element and/or the second pawl element are fan-shaped.
In a further embodiment, the first pawl element and the second pawl element are arranged on countershaft, and the axis of countershaft is with main axis parallel and do not overlap with main shaft, and countershaft and main shaft are connected, and can drive main axis.
In a further embodiment, countershaft is located among main shaft.
In a further embodiment, spring is provided with in reversing switch, reversing switch comprises newel, the first bulb plunger and the second bulb plunger, newel is placed through in main shaft, first bulb plunger and the second bulb plunger are fixed on newel successively, and the first bulb plunger and the second bulb plunger coordinate with the first pawl element and the second pawl element respectively.
In a further embodiment, spring is provided with in the first bulb plunger and the second bulb plunger.
Slim reversible ratcheting tool of the present utility model is thinned the thickness (namely along the length that main shaft 100 extends) of each parts in operate portions on the basis reaching required output torque, therefore the thickness of operate portions entirety is also reduced greatly, namely also easy to use in narrow space, and the moment of torsion met needed for tightening fastener parts, achieve two kinds of mode of operations and can stablize between two kinds of mode of operations and change easily.
Be described further below with reference to the technique effect of accompanying drawing to design of the present utility model, concrete structure and generation, to understand the purpose of this utility model, characteristic sum effect fully.
Detailed description of the invention
As illustrated in fig. 1 and 2, comprise handle 20 and operate portions 10 according to the slim reversible ratcheting tool of a specific embodiment of the present utility model, handle 20 is extending longitudinally and be socketed on operate portions 10 by the head 21 (see Fig. 3) of its ring-type.Operate portions 10 inside is provided with main shaft 100, outside is provided with gripper rings 102.One end of main shaft 100 be extend to operate portions 10 and handle 20 head 21 outside output 101.Output 101 can by installing different sleeves to be configured to the configuration being applicable to operate the various securing members such as exterior angle screw.
The reversing arrangement that slim reversible ratcheting tool of the present utility model comprises transmission device and connects with it, be sent to the main shaft 100 of operate portions 10 by transmission device from the input torque of handle 20, and the direction of the output torque optionally making output 101 export by reversing arrangement is first direction or second direction, wherein first direction is contrary with second direction.Such as, the input torque of operate portions 10 is clockwise moment or counter clockwise direction moment, and the output torque that output 101 exports is clockwise moment; Or the input torque of operate portions 10 is clockwise moment or counter clockwise direction moment, and the output torque that output 101 exports is counter clockwise direction moment.
The structure of the transmission device of slim reversible ratcheting tool of the present utility model as shown in Figure 3, comprises the first ratchet face 311, driving gear 312, second ratchet face 321, driven gear 322, intermediate gear shaft 330, idler gear 331 and 332.Wherein, first ratchet face 311 is connected with driving gear 312 and coaxial, in the present embodiment, first ratchet face 311 is fixedly arranged on the inner ring of the head 21 of the ring-type of handle 20, driving gear 312 is fixedly connected on the head 21 of handle 20, and like this when handle 20 rotates, its head 21 can drive driving gear 312 to rotate simultaneously, in other embodiments, the first ratchet face 311 also can be arranged on the inner ring of driving gear 312; Second ratchet face 321 is arranged on the inner ring of driven gear 322.First ratchet face 311 is relative with the outer peripheral face of main shaft 100 with the flank of tooth of the second ratchet face 321; Driving gear 312 and driven gear 322 are face gears, and the flank of tooth of driving gear 312 and driven gear 322 toward each other.The all coaxial and central axes of its central axis and main shaft 100 of first ratchet face 311, second ratchet face 321, driving gear 312 and driven gear 322.
Intermediate gear shaft 330 and gripper rings 102 are fixedly linked, and idler gear 331,332 is arranged on intermediate gear shaft 330, and intermediate gear shaft 330 is vertical with main shaft 100.Idler gear 331,332 is engaged between driving gear 312 and driven gear 322, their tooth respectively with the indented joint transmission on the flank of tooth of driving gear 312 and driven gear 322, when gripper rings 102 is fixed, that is intermediate gear shaft 330 is when maintaining static, when driving gear 312 rotates, driven gear 322 and its reverse rotation can be driven by idler gear 331,332.In the present embodiment, idler gear 331,332 is all bevel gear.
The structure of the reversing arrangement of slim reversible ratcheting tool of the present utility model as shown in Figure 4, comprises the reversing switch and the first pawl element 211 and the second pawl element 212 that are made up of newel 220, first bulb plunger 221, second bulb plunger 222 and spring 224.Wherein, newel 220 is installed in main shaft 100, spring 224 is on center shaft sheathed, between the first end 2201 and main shaft 100 of newel 220, first bulb plunger 221 and the second bulb plunger 222 are fixed on newel 220 successively, first bulb plunger 221 is vertical with main shaft 110 with the activity direction of the bulb part of the second bulb plunger 222, preferably, in the first bulb plunger 221 and the second bulb plunger 222, is combined with the flexible members such as spring.First pawl element 211 and the second pawl element 212 are arranged on main shaft 100 by countershaft 210, as shown in Figure 5, countershaft 210 is parallel to main shaft 100 but its central axis does not coincide with the central axis of main shaft 100, and the first pawl element 211 and the second pawl element 212 can rotate around countershaft 210.
First pawl element 211 is similar with the structure of the second pawl element 212, all comprises the first fan-shaped ratchet, the second fan-shaped ratchet and fan-shaped mid portion between the two.For the first pawl element 211, Fig. 6 shows the top view (direction namely along main shaft 100 to output 101) of the first pawl element 211, as can be seen from Figure 6, the first pawl element 211 comprises the first fan-shaped ratchet 2111, second fan-shaped ratchet 2112 and fan-shaped mid portion 2110 between the two.The fan-shaped tooth surface of the fan-shaped tooth surface of the first fan-shaped ratchet 2111, the sector of fan-shaped mid portion 2110 and the second fan-shaped ratchet 2112 constitutes the first surface of the first pawl element 211.First pawl element 211 also has second surface, and this is a shaped face, and in the present embodiment, it comprises a recess 2113, and recess 2113 has the first side wall 2114 and the second sidewall 2115.The first side wall 2114 and the second sidewall 2115 all main shaft 100 direction extend.Have the via hole 2101 coordinated with countershaft 210 in first pawl element 211, the first pawl element 211 is arranged on (as shown in Figure 5) on main shaft 100 through via hole 2101 by countershaft 210.In the present embodiment, via hole 2101 is arranged on the fan-shaped mid portion 2110 of the first pawl element 211, preferably, is arranged on the center of gravity place of the first pawl element 211.The structure of the second pawl element 212 is similar to the first pawl element 211, be not repeated herein, its thickness (namely along the length that main shaft 100 extends) is less than the thickness of the first pawl element 211 in the present embodiment, but in other embodiments, its thickness also can be equal with the thickness of the first pawl element 211, or be greater than the thickness of the first pawl element 211.
First pawl element 211 is relative with the flank of tooth of the first ratchet face 311 and the second ratchet face 321 respectively with the first surface of the second pawl element 212, particularly, the tooth of the fan-shaped ratchet (comprising the first fan-shaped ratchet 2111 and the second fan-shaped ratchet 2112) of the first pawl element 211 is relative with the tooth of the first ratchet face 311, and the tooth of the fan-shaped ratchet (comprising the first fan-shaped ratchet and the second fan-shaped ratchet) of the second pawl element 212 is relative with the tooth of the second ratchet face 321.First pawl element 211 is relative with the surface of newel 220 respectively with the second surface of the second pawl element 212, particularly, the second surface of the first pawl element 211 divides relative with the ball head of the first bulb plunger 221, and the second surface of the second pawl element 212 divides relative with the ball head of the second bulb plunger 222.By pivot post 220, the first side wall 2114 of the recess 2113 of bulb part contact first pawl element 211 of the first bulb plunger 221 can be made, make the first side wall of the recess of bulb part contact second pawl element 212 of the second bulb plunger 222, now slim reversible ratcheting tool of the present utility model is in the first mode of operation simultaneously; Or, make the second sidewall 2115 of the recess 2113 of bulb part contact first pawl element 211 of the first bulb plunger 221, make the second sidewall of the recess of bulb part contact second pawl element 212 of the second bulb plunger 222, now slim reversible ratcheting tool of the present utility model is in the second mode of operation simultaneously.
When slim reversible ratcheting tool of the present utility model is in the first mode of operation, as shown in Figure 7, the tooth of the first fan-shaped ratchet 2111 of the first pawl element 211 and the tooth contact of the first ratchet face 311, equally, the tooth of the first fan-shaped ratchet of the second pawl element 212 and the tooth contact of the second ratchet face 321.When the head 21 of handle 20 drives the first ratchet face 311 to rotate, when the direction of motion of the tooth of the first ratchet face 311 at the first fan-shaped ratchet 2111 place is for pointing to the second fan-shaped part 2112 from the first fan-shaped part 2111, namely when the first ratchet face 311 as shown in Figure 7 rotates clockwise, due to the first bulb plunger 221 bulb part contact be the first side wall 2114 of the recess 2113 of the first pawl element 211, first ratchet face 311 can drive the first pawl element 211 to play rotation with one, the i.e. tooth of the first fan-shaped ratchet 2111 and the indented joint transmission of the first ratchet face 311, the countershaft 210 that rotates through of the first pawl element 211 is passed to main shaft 100, thus drive main shaft 100 to rotate, and when the direction of motion of the tooth of the first ratchet face 311 at the first fan-shaped ratchet 2111 place is for pointing to the first fan-shaped part 2111 from the second fan-shaped part 2112, namely when the first ratchet face 311 as shown in Figure 7 rotates counterclockwise, ball working portion due to the first bulb plunger 221 contacts the first side wall 2114 of the recess 2113 of the first pawl element 211, first ratchet face 311 can not drive the first pawl element 211 to play rotation with one, i.e. the tooth of the first fan-shaped ratchet 2111 and the tooth not couple drive of the first ratchet face 311.
Simultaneously, when the direction of motion of the tooth of second ratchet face 321 at the first fan-shaped ratchet place at the second pawl element 212 is point to the second scallop timesharing from the first fan-shaped part of the second pawl element 212, namely when the second ratchet face 321 rotates clockwise, the first side wall of what the ball working portion due to the second bulb plunger 222 contacted the is recess of the second pawl element 212, second ratchet face 321 can drive the second pawl element 212 to play rotation with one, the i.e. tooth of the first fan-shaped ratchet of the second pawl element 212 and the indented joint transmission of the second ratchet face 321, the countershaft 210 that rotates through of the second pawl element 212 is passed to main shaft 100, thus drive main shaft 100 to rotate, and when the direction of motion of the tooth of the second ratchet face 321 at the first fan-shaped ratchet place of the second pawl element 212 is point to the first scallop timesharing from the second fan-shaped part of the second pawl element 212, namely when the second ratchet face 321 rotates counterclockwise, ball working portion due to the second bulb plunger 222 contacts the first side wall of the recess of the second pawl element 212, second ratchet face 321 can not drive the second pawl element 212 to play rotation with one, i.e. the tooth of the first fan-shaped ratchet of the second pawl element 212 and the tooth not couple drive of the second ratchet face 321.。
Due to the transmission of aforesaid idler gear 331,332 and driving gear 312 and driven gear 322, when gripper rings 102 maintains static, the rotation direction of the second ratchet face 321 is contrary with the first ratchet face 311.It can thus be appreciated that, the first mode of operation is at slim reversible ratcheting tool of the present utility model, when the input torque from operate portions 10 is clockwise moment, it makes the first ratchet face 311 rotate clockwise, and the second ratchet face 321 rotates counterclockwise, and now the first pawl element 211 connects with the first ratchet face 311, second pawl element 212 does not connect with the second ratchet face 321, thus, the first pawl element 211 makes main shaft 100 rotate clockwise, and output torque is clockwise moment; When the input torque from operate portions 10 is anticlockwise moment, it makes the first ratchet face 311 rotate counterclockwise, second ratchet face 321 rotates clockwise, now the first pawl element 211 does not connect with the first ratchet face 311, second pawl element 212 connects with the second ratchet face 321, thus, the second pawl element 212 makes main shaft 100 rotate clockwise, and output torque is clockwise moment.
When slim reversible ratcheting tool of the present utility model is in the second mode of operation, the tooth of the second fan-shaped ratchet 2112 of the first pawl element 211 and the tooth contact of the first ratchet face 311, equally, the tooth of the second fan-shaped ratchet of the second pawl element 212 and the tooth contact of the second ratchet face 321.When the input torque from operate portions 10 makes the first ratchet face 311 rotate, when the direction of motion of the tooth of the first ratchet face 311 at the second fan-shaped ratchet 2112 place is for pointing to the second fan-shaped part 2112 from the first fan-shaped part 2111, namely when the first ratchet face 311 rotates clockwise, due to the second sidewall 2115 of the recess 2113 of bulb part contact first pawl element 211 of the first bulb plunger 221, first ratchet face 311 can not drive the first pawl element 211 to play rotation with one, i.e. the tooth of the second fan-shaped ratchet 2112 and the tooth not couple drive of the first ratchet face 311, and when the direction of motion of the tooth of the first ratchet face 311 at the second fan-shaped ratchet 2112 place is for pointing to the first fan-shaped part 2111 from the second fan-shaped part 2112, namely when the first ratchet face 311 rotates counterclockwise, due to the first bulb plunger 221 bulb part contact be the second sidewall 2115 of the recess 2113 of the first pawl element 211, first ratchet face 311 can drive the first pawl element 211 to play rotation with one, the i.e. tooth of the second fan-shaped ratchet 2112 and the indented joint transmission of the first ratchet face 311, the countershaft 210 that rotates through of the second pawl element 212 is passed to main shaft 100, thus drive main shaft 100 to rotate.
Simultaneously, when the direction of motion of the tooth of second ratchet face 321 at the second fan-shaped ratchet place at the second pawl element 212 is point to the second scallop timesharing from the first fan-shaped part of the second pawl element 212, namely when the second ratchet face 321 rotates clockwise, due to the second sidewall of the recess of bulb part contact second pawl element 212 of the second bulb plunger 222, second ratchet face 321 can not drive the second pawl element 212 to play rotation with one, i.e. the tooth of the second fan-shaped ratchet of the second pawl element 212 and the tooth not couple drive of the second ratchet face 321, and when the direction of motion of the tooth of the second ratchet face 321 at the second fan-shaped ratchet place of the second pawl element 212 is point to the first scallop timesharing from the second fan-shaped part of the second pawl element 212, namely when the second ratchet face 321 rotates counterclockwise, second sidewall of what the ball working portion due to the second bulb plunger 222 contacted the is recess of the second pawl element 212, second ratchet face 321 can drive the second pawl element 212 to play rotation with one, the i.e. tooth of the second fan-shaped ratchet of the second pawl element 212 and the indented joint transmission of the second ratchet face 321, the countershaft 210 that rotates through of the second pawl element 212 is passed to main shaft 100, thus drive main shaft 100 to rotate.
Due to the transmission of aforesaid idler gear 331,332 and driving gear 312 and driven gear 322, when gripper rings 102 maintains static, the rotation direction of the second ratchet face 321 is contrary with the first ratchet face 311.It can thus be appreciated that, the second mode of operation is at slim reversible ratcheting tool of the present utility model, when the input torque from operate portions 10 is clockwise moment, it makes the first ratchet face 311 rotate clockwise, and the second ratchet face 321 rotates counterclockwise, and now the first pawl element 211 does not connect with the first ratchet face 311, second pawl element 212 connects with the second ratchet face 321, thus, the second pawl element 212 makes main shaft 100 rotate counterclockwise, and output torque is anticlockwise moment; When the input torque from operate portions 10 is anticlockwise moment, it makes the first ratchet face 311 rotate counterclockwise, second ratchet face 321 rotates clockwise, now the first pawl element 211 connects with the first ratchet face 311, second pawl element 212 does not connect with the second ratchet face 321, thus, the first pawl element 211 makes main shaft 100 rotate counterclockwise, and output torque is anticlockwise moment.
As previously mentioned, by pivot post 220, can make to switch between the first mode of operation of slim reversible ratcheting tool of the present utility model and the second mode of operation, select.In order to easy to use, in the present embodiment, as shown in Figure 8, be provided with turn-button 223 at the first end of newel 220, embed turn-button 223 by making the Liang Ge ear of newel 220 (ear 2201 as in Fig. 8) and realize coordinating between newel 220 with turn-button 223.Like this, by rotating turn-button 223, newel 220 can be made to rotate.Turn-button 223 in the present embodiment is provided with the spine that two protrude from the surface of turn-button 223, as spine 2231, can by applying turning moment to the Liang Tiao spine comprising spine 2231 to rotate turn-button 223 during use.
Slim reversible ratcheting tool of the present utility model also comprises stopping means, and it makes slim reversible ratcheting tool of the present utility model remain on selected mode of operation until user is switched to other mode of operation.As shown in Figures 9 and 10, stopping means in the present embodiment comprises the hoodle 400 between the second end that 224, one, a spring be set on newel 220 is arranged on output 101 and newel 220, and at the groove that the hoodle 400 of the second end of newel 220 coordinates, be in particular the first groove 410 and the second groove 420.First groove 410 and the second groove 420 extend parallel to each other and are separated by smooth ridge between the two, and direction and the newel axial direction of ridge have an inclination angle.
Spring 224 makes newel 220 and main shaft 100 keep one from the second end 2202 of newel 220 towards the power of first end 2201, and now hoodle 400 is positioned at the first groove 410 or the second groove 420 near the second end 2202 side.When rotating turn-button 223, spring 224 is compressed, hoodle 400 is positioned at the first groove 410 or the second groove 420 near first end 2201 side, now hoodle 400 can enter the second groove 420 from the first groove 410 or enter the first groove 410 from the second groove 420, and makes hoodle 400 be reset to the first groove 410 and the second groove 420 near the second end 2202 side under force.
When hoodle 400 is in the first groove 410, first bulb plunger 221 and the ball working portion of the second bulb plunger 222 keep contacting of the first side wall of itself and the first pawl element 211 and the recess of the second pawl element 212, and namely slim reversible ratcheting tool of the present utility model is maintained at the first mode of operation; When hoodle 400 is in the second groove 420, first bulb plunger 221 and the ball working portion of the second bulb plunger 222 keep contacting of the second sidewall of itself and the first pawl element 211 and the recess of the second pawl element 212, and namely slim reversible ratcheting tool of the present utility model is maintained at the second mode of operation.When rotation turn-button 223, newel 220 is rotated, and when making hoodle 400 enter the second groove 420 from the first groove 410, slim reversible ratcheting tool of the present utility model enter the second mode of operation from the first mode of operation; When rotation turn-button 223, newel 220 is rotated, and when making hoodle 400 enter the first groove 410 from the second groove 420, slim reversible ratcheting tool of the present utility model enter the first mode of operation from the second mode of operation.
In the present embodiment, intermediate gear shaft 330 is fixedly connected with gripper rings 102, intermediate gear shaft 330 is fixed relative to gripper rings 102, thus when operate portions 20 is rotated relative to gripper rings 102, idler gear 331,332 makes the rotation direction of driven gear 322 contrary with the rotation direction of driving gear 312.In use, work to make idler gear 331,332, to ensure that the rotation direction of the second ratchet face 321 is contrary with the first ratchet face 311, user can make intermediate gear shaft 330 locate by the mode gripping gripper rings 102, thus idler gear 331,332 rotates under the drive of driving gear 312, and then drive driven gear 322 to rotate, thus the second ratchet face 321 and the first ratchet face 311 are oppositely rotated.It should be noted that, in other embodiments of the present utility model, other mode also can be taked to locate intermediate gear shaft 330, and idler gear 331,332 is worked.
In addition, as previously mentioned, the output 101 of slim reversible ratcheting tool of the present utility model can by installing different sleeves to be configured to the configuration being applicable to operate the various securing members such as exterior angle screw, now, each sleeve that the hoodle 400 in the stopping means of slim reversible ratcheting tool of the present utility model can also be used for being installed on output 101 carries out screens.
In the present embodiment, the first pawl element 211 adopts high-strength material (as injection powder metallurgy or No. 45 steel etc.), and the intensity of its material is compared the general powdered metallurgical material intensity used and improve 30%-40%.The thickness (namely along the length that main shaft 100 extends) of the first pawl element 211 is less than or equal to 6.5mm, identical with the thickness of the first pawl element 211 with the thickness of the first ratchet face 311 of the first pawl element 211 couple drive.The thickness of the second pawl element 212 is less than or equal to the thickness of the first pawl element 211, and meanwhile, the thickness between the front end face 3301 of intermediate gear shaft and rear end face 3302 is less than or equal to 8mm, and the modulus of idler gear is less than or equal to 1.Tooth on driving gear 312 and driven gear 322 and the indented joint transmission of idler gear.Therefore, the thickness (namely along the distance on main shaft 100 bearing of trend between the front surface 103 of gripper rings and the rear surface 104 of main shaft 100) of operate portions 10 is less than or equal to 30mm.
The present embodiment is thinned the thickness (namely along the length that main shaft 100 extends) of each parts in operate portions on the basis reaching required output torque, therefore the thickness of operate portions entirety is also reduced greatly, namely also easy to use in narrow space, and meet the moment of torsion needed for tightening fastener parts.
In another embodiment, first pawl element 211 adopts injection powder metallurgy, and the thickness of the first pawl element 211 is 5mm, and the thickness of the second pawl element 212 is less than the thickness of the first pawl element 211, idler gear axial thickness is 6mm, and the modulus of idler gear is 0.6.Tooth on driving gear 312 and driven gear 322 and the indented joint transmission of idler gear.The thickness of operate portions 10 is 25mm.
In other examples, also high-strength material can not be adopted, but by arranging the third and fourth pawl element in the position of the first pawl element and the second pawl element relative main symmetry, make can provide enough moments of torsion when the thickness of thinning pawl element, thus reach the object of thinning spanner thickness.
More than describe preferred embodiment of the present utility model in detail.Should be appreciated that the ordinary skill of this area just can make many modifications and variations according to design of the present utility model without the need to creative work.Therefore, all technical staff in the art according to design of the present utility model on the basis of existing technology by the available technical scheme of logical analysis, reasoning, or a limited experiment, all should by the determined protection domain of claims.