CN106075816B - One kind training cycling safeguard structure - Google Patents

Abstract

The invention discloses a sports protection structure for training bicycles. The protection structure adopts multiple groups of gear inner gears and gear outer gears with different diameters, and the number of gear inner gears is controlled by a shift lever group, which drives the gear outer gears to work correspondingly. The outer gear gear and the output gear cooperate with each other for output. The gear outer gear on the outer layer has different diameters to realize the regulation of exercise frequency, so that the exerciser can adjust the speed according to the exercise intensity to meet the use and exercise needs of different groups of people; through the hinged cushion and With the trigger switch, the exerciser grasps the handle and leans forward when exercising, and the seat cushion adapts forward. When the exerciser feels that the amount of exercise is too large and the body starts to load, he can lean back to drive the seat cushion to rotate and press the trigger switch to make the frequency control box The box body moves down to release the transmission of the output gear and the driven gear, so as to realize the suspension of passively driven motion. It has an effective protective effect, which is beneficial to ensure that the exerciser is not easy to be injured during the exercise, and the safety is better.

Description

A protective structure for training bicycles

technical field

The invention relates to the field of sports equipment, in particular to a sports protection structure for training bicycles.

Background technique

Generally, the cycling training bicycles used in the gym or at home are all exercised by people actively riding. This method allows people to complete physical exercise without leaving home. However, in the implementation, it will appear that the exercisers do not have strong perseverance to persist in exercising. After riding a bicycle a few times, they feel tired and stop riding. The effect of exercising and fitness cannot be achieved, and the training bicycle has become a decoration. If the function of passive riding can be added to the existing bicycle, the exerciser can still rely on the passive driving of the bicycle to complete the exercise after active pedaling fatigue, and maintain a certain heart rate and neuromuscular excitability. The effect of exercise, the way to ensure the intensity of exercise. In the process of passive riding, it is also quite necessary to provide effective protection for the exerciser to avoid damage to the body caused by sports equipment.

Contents of the invention

The technical problem to be solved by the present invention is to provide a sports protection structure for training bicycles that is easy to manufacture, easy to install, beneficial to ensure and adjust the exercise intensity of the exerciser, convenient for the exerciser to exercise independently, and effectively protected from injury.

In order to solve the above technical problems, the present invention adopts the following technical solutions: a sports protection structure for training bicycles, including a bicycle body and a frequency control box, the bicycle body includes a base, a bracket, wheels, pedals, a cushion and a handle, and the bracket is arranged on the base, The wheels include a pedal wheel and a driven wheel. The pedal wheel and the driven wheel are rotatably arranged on the bracket. The pedal wheel and the driven wheel are connected and linked by a belt. Above, the handle is located above the driven wheel, and a driven gear is arranged on the side of the driven wheel; the frequency control box is set on the base and is located on the side of the driven wheel. The external gear set of the gear position, the shift lever set, the motor and the output gear, and the push cylinder are rotatably arranged in the box, and the push rod of the push cylinder is set with the internal gear set of the gear position. The internal gear set of the gear position is magnetic, and the gear position The internal gear set includes several gear internal gears arranged from small to large from top to bottom. Several gear internal gears are integrated by magnetic attraction. The uppermost gear internal gear is fixed with the push rod and the upper end is flush. The external gear set is placed on the ring-shaped platform formed in the box. The gear external gear set includes several gear external gears arranged from small to large from top to bottom. The small external gears of several gears are set in the large ones. The upper surface of the gear outer gear is even, and the cross section of the gear gear is in the shape of “[” and has inner ring teeth and outer ring teeth. The gears correspond one by one, the shifting lever group is set on the side wall of the box body, the output gear is rotatably set on the upper part of the box body and coaxial with the push rod, the motor is set on the upper side of the box body and connected with Transmission teeth; when in use, adjust one of the shift lever groups to block the outer side of a certain gear internal gear, and the unblocked gear internal gear above this gear is driven up by the push cylinder, and the rising gear The gear inner gear cooperates with the matching gear outer gear and drives the gear gear to rise up against the lower surface of the output gear, and the lower surface of the output gear and the upper surface of the gear outer gear set cooperate with the transmission through the structure of the block and the groove. The motor moves through the slide rail to the drive gear and the external gear gear; the base is provided with an inclined platform, and the inclined platform is provided with an inclined rail. The positioning surface that restricts the sliding of the box body, the slidable sliding block is set on the inclined rail of the inclined table, the sliding block is against the other side of the box body relative to the positioning surface, the seat cushion is hinged on the bracket, and the trigger switch is also set on the bracket. The trigger switch is located at the bottom of the rear part of the seat cushion, and the trigger switch is connected with the slide block signal. When the seat cushion rotates backward and presses the trigger switch, the trigger slide block slides downward, and the casing slides down to separate the output gear and the driven gear.

As an improvement, the outer teeth of the gear internal gear and the inner ring teeth matched with the gear external gear are all bevel gears, the bevel gears are small at the top and large at the bottom.

As an improvement, the push rod is also sleeved with a magnetic bottom wheel, which is located at the lower end of the internal gear set and has a diameter larger than the largest internal gear; when the shift rod set does not block the internal gear set When it is connected with the bottom wheel, the gear inner gear set and the bottom wheel rise together, the gear inner gear and the gear outer gear match one by one, and the bottom wheel drags the lowermost gear outer gear from the bottom; when the shift lever group blocks When the bottom wheel or any gear internal gear, the unblocked gear internal gear rises to cooperate with the gear external gear, the lowest gear internal gear does not drive the corresponding gear external gear and only drags the upper gear bit external gear.

As an improvement, the gearshift lever group includes several gearshift levers, the gearshift lever includes a straight rod and a semi-circular arc rod arranged at one end of the straight rod, a rotating shaft is arranged in the middle of the straight rod, and the push rods arranged from top to bottom The radius of the semi-arc rod is set from small to large.

As an improvement, a number of positioning posts are arranged on the push rod. The positioning posts cooperate with a spring to be arranged in the movable groove and are limited by a cover. The spherical end of the positioning post protrudes from the opening in the middle of the cover. Fit with the positioning hole on the gear internal gear.

The beneficial effects achieved by the present invention are: the bicycle body is provided with a frequency control box, and the exerciser can change the automatic riding into the passive riding driven by the motor, providing a forced exercise mode for those who are lazy or difficult to insist on riding a bicycle, or for those who exercise Exercisers exercise at a stable exercise frequency to improve the effect of exercise; multiple sets of internal gears and external gears with different diameters are used, and the number of internal gears is controlled by the shift lever group, which drives the same number of gears. The gear external gear works, the gear external gear and the output gear cooperate to output, the external gear of the outer gear has a different diameter selected, and when driven by the motor, the gear ratio of the transmission gear and the external gear of the gear can output differently to the wheel. The speed can be adjusted to realize the regulation of exercise frequency, so that the exerciser can adjust the speed according to the exercise intensity, so as to adapt to the use and exercise needs of different groups of people. Through the cooperation of the hinged seat cushion and the trigger switch, the exerciser grabs the handle and leans forward when exercising, and the seat cushion adapts forward. When the exerciser feels that the exercise is too heavy and the body begins to load, the exerciser can drive the seat cushion to rotate to press the trigger. The switch makes the box body move down to release the transmission of the output gear and the driven gear, so as to realize the suspension of passively driven motion. It has an effective protective effect, which is beneficial to ensure that the exerciser is not easy to be injured during the exercise, and the safety is better.

Description of drawings

Fig. 1 is a schematic diagram of the stop state structure of the training bicycle of the present invention.

Fig. 2 is a schematic structural diagram of the working state of the training bicycle of the present invention.

Fig. 3 is a schematic structural diagram of the stop state of the frequency control box of the present invention.

Fig. 4 is a schematic diagram of the structure of the working state of the frequency control box of the present invention.

Fig. 5 is a partially enlarged schematic diagram of the cooperation between the gear internal gear set and the gear external gear set in the present invention.

Fig. 6 is a partial enlarged schematic diagram II of cooperation between the internal gear set and the external gear set in the present invention.

Fig. 7 is a schematic diagram of the structure of the shift lever group in working state according to the present invention.

detailed description

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

As shown in Figures 1-7, the embodiment of the exercise protection system based on exercise frequency induction provided by the present invention includes a bicycle body 1 and a frequency control box 2, and the bicycle body 1 includes a base 11, a support 12, wheels 13, pedal 14, cushion 15 and handle 16, bracket 12 is arranged on the base 11, wheel 13 comprises pedal wheel 13a and driven wheel 13b, pedal wheel 13a and driven wheel 13b are rotatably arranged on the bracket 12, pedal wheel 13a and Driven wheel 13b is connected linkage by belt 17, and pedal 14 is set on pedal wheel 13a, and seat cushion 15 and handle 16 are all arranged on the support 12, and seat cushion 15 is positioned at pedal wheel 13a top, and handle 16 is positioned at driven wheel 13b top, the side of driven wheel 13b A driven gear 13c is arranged on the side; the frequency control box 2 is arranged on the base 11 and is located on the side of the driven wheel 13b, and the frequency control box 2 includes a box body 21, a push cylinder 22, a gear internal gear set 23, and a gear external gear Group 24, shift lever group 25, motor 26 and output gear 27, and the push cylinder 22 is rotatably arranged in the box body 21, and the push rod 22a of the push cylinder 22 is sleeved with a gear set 23, the gear internal gear Group 23 has magnetism, and gear internal gear set 23 comprises several internal gears 23a arranged from small to large from top to bottom. Several internal gears 23a are magnetically attracted into one body. The push rod 22a is fixedly arranged and its upper end is flush. The external gear set 24 is placed on the annular platform 21a formed in the box body 21. The external gear set 24 includes several external gears arranged from small to large from top to bottom. Gear 24a, the small ones of several gears 24a are set in the big one, the upper surfaces of all gears 24a are flush, and the cross section of gears 24a is in the shape of “[” and has inner ring teeth 24b and outer rings. Teeth 24c, the size of the inner ring where the inner ring teeth 24b are located increases sequentially from top to bottom and corresponds to the gear internal gear 23a one by one. The rotating one is set on the upper part of the box body 21 and coaxial with the push rod 22a, and the motor 26 is set on the upper side of the box body 21 and is connected with a transmission tooth 26a; Block the outside of a certain gear internal gear 23a, and the unblocked gear internal gear 23a above the gear internal gear 23a is driven up by the push cylinder 22, and the rising gear internal gear 23a and the matching gear external gear 24a Cooperate and drive the gear position external gear 24a to rise up against the lower surface of the output gear 27, the lower surface of the output gear 27 and the upper surface of the gear position external gear set 24 cooperate with the transmission through the structure of the block 31 and the card groove 32, and the motor 26 passes through the sliding The rail 26b moves to the transmission gear 26a and the gear external gear 24a for transmission; the base 11 is provided with an inclined platform 81, and the inclined platform 81 is provided with an inclined rail, and the box body 21 is slidable and arranged on the inclined platform 81 in cooperation with the inclined rail. The side of platform 81 upper end is provided with the positioning surface 82 that limits casing 21 to slide up, and the inclined rail of inclined platform 81 A slidable sliding block 83 is arranged on the top, and the sliding block 83 is against the other side of the box body 21 relative to the positioning surface 82. The seat cushion 15 is hinged on the support 12, and the support 12 is also provided with a trigger switch 4, which is located on the seat cushion 15. At the bottom of the rear part, the trigger switch 4 is connected with the sliding block 83 signal. When the seat cushion 15 rotates backward and presses the trigger switch 4, the trigger sliding block 83 slides downward, and the box body 21 slides down so that the output gear 27 and the driven gear 13c are separated. . Each part of the bicycle body 1 of the present invention is an ordinary fitness training bicycle structure, and the exerciser can be used as a general active riding when not connecting the frequency control box 2; the frequency control box is connected at the driven wheel 13b and the driven gear 13c 2. It can be connected to external power for passive riding to achieve the effect of compulsory and constant intensity exercise. The present invention realizes gear switching of different strengths and speeds through the cooperation of multiple sets of gear internal gears 23a and gear external gears 24a, for exercisers to choose and use. A plurality of internal gears 23a of gears are attracted to each other by magnetism, and the internal gears 23a of the uppermost gear are located at the end of the push rod 22a and are integrated with the push rod 22a. On it, the internal gears 23a of the gears are all sleeved on the push rod 22a. When the push cylinder 22 is started, the push rod 22a drives the internal gears 23a of the gears to rise. part; the exerciser can pre-adjust the shifting lever group 25, wherein the shifting lever 25a has different specifications and sizes, when selecting and operating a certain shifting lever 25a to block the corresponding gear internal gear 23a, the corresponding gear The gear internal gear 23a and the gear internal gear 23a below it all will break away from the gear internal gear 23a above because of being blocked, and the gear internal gear 23a above continues to move and reaches the gear external gear 24a. The external gear 24a will be driven by the gear internal gear 23a to rise to the output gear 27; after being in place, the motor 26 on the side moves on the slide rail 26b until the transmission gear 26a cooperates with the gear external gear 24a, and the motor 26 can work. Transmission, output gear 27 can drive driven gear 13c and driven wheel 13b to rotate together, has realized the output of power, the pedal 14 of exerciser's pedal wheel 13a place, can passively ride along with power, plays compulsory exercise and fixed The effect of strength training; and due to the use of multiple groups of gear internal gears 23a and gear external gears 24a with different diameters, the number of gear internal gears 23a is controlled by the shift lever group 25, and the corresponding number of gear external gears is driven 24a work, the gear position external gear 24a of outer layer is because the diameter of selection is different, when being driven by motor 26, the tooth number ratio of drive gear 26a and gear position external gear 24a is different and can output different speeds to wheel 13, realizes motion frequency control, makes The exerciser adjusts the speed according to the exercise intensity, so as to adapt to the use and exercise needs of different groups of people. The structure of the clamping block 31 and the clamping groove 32 makes the external gear set 24 and the output gear 27 become a stable whole to carry out the transmission output when mating, the output effect of force is good, the passive riding is stable, and the wear and tear between parts is small. The specific structure arranged on the base 11, that is, the box body 21 is positioned on the ramp of the inclined platform 81, and the box body 21 can slide down by operating the sliding block 83, so that the output gear 27 and the driven gear 13c are separated, thereby training The bicycle can have the original active riding function; when the sliding block 83 and the positioning surface 82 stably position the box body 21, it is ensured that the output gear 27 and the driven gear 13c are well meshed and coordinated, and the switching function of the active and passive exercise of the training bicycle is improved. . Cooperate with trigger switch 4 by hinged seat cushion 15 on the other hand, exerciser grasps handle 16 and leans forward when exercising, and seat cushion 15 is adaptive forward; Drive the cushion 15 to rotate to press the trigger switch 4, the trigger switch 4 feeds back the signal to the sliding block 83, the sliding block 83 slides down to make the box body move down to release the transmission of the output gear 27 and the driven gear 13c, so as to realize the suspension of the passively driven movement and start An effective protective effect is achieved, which is conducive to ensuring that the exerciser is not easily injured during exercise, and the safety is better.

As an improved specific embodiment, the external teeth of the gear internal gear 23a and the internal ring teeth 24b matched with the gear external gear 24a are both bevel gears, the bevel gears are small at the top and large at the bottom. As shown in Fig. 6, the gear internal gear 23a is used to support the upward support of the gear external gear 24a by adopting a bevel gear with a small top and a large bottom. , the push cylinder 22 is rotatably arranged in the box body 21, which may be a similar structure of the lower turntable, and rotates together with the gear internal gear 23a.

As an improved specific embodiment, the push rod 22a is also sheathed with a magnetic bottom wheel 6, which is located at the lower end of the gear set 23 and has a diameter larger than the largest internal gear 23a; When the lever group 25 did not block the internal gear set 23 and the bottom wheel 6, the internal gear set 23 and the bottom wheel 6 rose together, and the internal gear 23a and the external gear 24a matched one by one, and the bottom wheel 6 started from The lower part drags the lowest gear external gear 24a; when the shift lever group 25 blocks the bottom wheel 6 or any gear internal gear 23a, the unblocked gear internal gear 23a rises to cooperate with the gear external gear 24a, The lowest gear internal gear 23a does not drive the corresponding gear external gear 24a and only drags the upper gear gear 24a. As shown in Figure 5, it is an embodiment in which the lowermost gear internal gear 23a does not drive the corresponding gear outer gear 24a and only drags the upper gear gear 24a. This method relies on one more gear The inner gear 23a supports and stabilizes the outer gear 24a on the upper level, so that the cooperation between the outer gear 24a, the upper output gear 27 and the side transmission teeth 26a is more stable and does not deviate, ensuring the efficient use of components , to ensure the service life. And when all the internal gears 23a of the gears are all raised, the magnetic bottom wheel 6 is set as the support structure at the bottom to support the external gears 24a of the lowest gear, and the positioning column 51 and the positioning hole can also be set on the external gears 24a of the gears. The structure of 55 is reinforced and stabilized.

As an improved specific embodiment, the gearshift lever group 25 includes several gearshift levers 25a, and the gearshift lever 25a includes a straight rod 71 and a semicircular arc rod 72 arranged at one end of the straight rod 71, and the middle part of the straight rod 71 is provided with a rotating shaft. 73, the radii of the semicircular arc rods 72 on the push rods 22a arranged from top to bottom are set from small to large. Some shifting levers 25a adopt a simple up-and-down arrangement design, and rotate around a rotating shaft 73, the exerciser can manually operate the shifting levers 25a, and also can be connected with an electric switch to realize external switch control. One end of the straight rod 71 stretches out from the box body 21 for manual operation, and the other end is connected with a semi-arc rod 72. The semi-arc rod 72 can block the gear internal gear 23a with a large diameter and allow the gear with a small diameter to pass smoothly, so as to achieve good control For the effect of shifting gears, the shifting lever 25a of each layer will not affect each other, and the gear position will be determined due to the blocking of the shifting lever 25a of the uppermost layer.

As an improved specific embodiment, the push rod 22a is provided with several positioning posts 51, the positioning posts 51 cooperate with a spring 52 to be arranged in the movable groove 53 and are limited by a blocking cover 54, and the spherical end of the positioning post 51 moves from The opening in the middle of the blocking cover 54 protrudes, and the positioning column 51 is engaged with the positioning hole 55 on the gear internal gear 23a. The above structure has improved the stability of the positioning transmission of the internal gear 23a of the gear position on the push rod 22a. Several internal gears 23a of the gear position are integrated and stabilized at the end of the push rod 22a by magnetic force, and the upper positioning column 51 is stuck in the positioning hole 55. The gear internal gear 23a can be effectively positioned, so that the cooperation between the gear internal gear 23a and the gear external gear 24a is stable, and the gear external gear 24a is better in contact with the upper output gear 27 and the side transmission teeth 26a. When the gear lever 25a blocks the lower gear internal gear 23a, the spherical end of the positioning column 51 will be pushed into the movable groove 53 so that the lock can be released. When the push rod 22a is retracted, it can be snapped back into the gear position by pushing the retracting force of the cylinder 22. The gear 23a and the spring 52 provide the outward thrust of the positioning column 51, and the cover 54 is a detachable structure, which is convenient for replacing the positioning column 51 that has been used for a long time and is seriously worn out, prolongs the service life of the frequency control box 2, and ensures the transmission effect .

Claims (6)

1. one kind training cycling safeguard structure, it is characterised in that：It is described including bicycle body (1) and frequency regulation box (2) Bicycle body (1) includes base (11), support (12), wheel (13), pedal (14), cushion (15) and handle (16), the branch Frame (12) is arranged on base (11), and the wheel (13) includes pedal wheel (13a) and driven pulley (13b), the pedal wheel (13a) and driven pulley (13b) are spindle rotationally arranged on support (12), and the pedal wheel (13a) and driven pulley (13b) pass through skin Band (17) connection links, and pedal (14) is set on the pedal wheel (13a), the cushion (15) and handle (16) are arranged at branch On frame (12), the cushion (15) is located above pedal wheel (13a), and the handle (16) is located above driven pulley (13b), described The side of driven pulley (13b) is provided with a driven gear (13c)；The frequency regulation box (2) is arranged on base (11) and position In driven pulley (13b) side, the frequency regulation box (2) includes casing (21), pusher cylinder (22), gear internal gear group (23), gear external gear group (24), stick group (25), motor (26) and output gear (27), the pusher cylinder (22) can Being arranged in casing (21) for rotation, gear internal gear group (23), institute are arranged on the catch bar (22a) of the pusher cylinder (22) Stating gear internal gear group (23) has magnetic, and the gear internal gear group (23) includes some of ascending arrangement from top to bottom Gear internal gear (23a), some gear internal gears (23a) are attracted to be integrally formed by magnetic, the gear internal gear (23a) of topmost Concordant with catch bar (22a) fixed setting and upper end, the gear external gear group (24) is positioned over the ring formed in casing (21) Shape platform (21a) place, the gear external gear group (24) include some gear external gears of ascending arrangement from top to bottom (24a), some gear external gears (24a) it is small be enclosed on it is big in, the upper surface of all gear external gears (24a) is concordant, The section of the gear external gear (24a) is in " [" shape and having inner circular tooth (24b) and outer shroud tooth (24c), the inner circular tooth Interior ring size where (24b) increases successively from top to bottom and, the stick group corresponding one by one with gear internal gear (23a) (25) be arranged in the side wall of casing (21), the output gear (27) be rotatably arranged on casing (21) top and with promotion Bar (22a) concentric setting, the motor (26) are arranged on the upper side of casing (21) and are connected with driving cog (26a)； The a certain outside for stopping some gear internal gear (23a) in stick group (25), the gear internal gear are adjusted during use The gear internal gear (23a) not being blocked on (23a) is driven by pusher cylinder (22) to be risen, the gear internal gear of rising (23a) is against output gear (27) following table with the gear external gear (24a) matched with drive gear external gear (24a) rising is merged Face, the lower surface of the output gear (27) and the upper surface of gear external gear group (24) pass through fixture block (31) and neck (32) Respective outer side edges are driven, and motor (26) is moved to driving cog (26a) by slide rail (26b) and coordinates transmission with gear external gear (24a)； The base (11) is provided with sloping platform (81), is provided with ramp on the sloping platform (81), the casing (21) slidably with ramp It is equipped with sloping platform (81), the side of sloping platform (81) upper end sets locating surface (82) sliding on limitation casing (21), Slidable sliding shoe (83) is set in the ramp of the sloping platform (81), and the sliding shoe (83) is against casing (21) relative positioning The opposite side in face (82), the cushion (15) are hinged on support (12), and trigger switch is additionally provided with the support (12) (4), the trigger switch (4) is located at the lower section at cushion (15) rear portion, and the trigger switch (4) connects with sliding shoe (83) signal Connect, when cushion (15) back rotation is pressed onto trigger switch (4), triggering sliding shoe (83) slide downward, casing (21) downslide makes defeated Go out gear (27) and driven gear (13c) is separated.

A kind of 2. training cycling safeguard structure according to claim 1, it is characterised in that：The gear internal gear The inner circular tooth (24b) that the external tooth of (23a) is engaged with gear external gear (24a) is angular wheel, under small on the angular wheel Greatly.

A kind of 3. training cycling safeguard structure according to claim 1, it is characterised in that：The catch bar (22a) On be also arranged with the magnetic return pulley (6) of tool, the return pulley (6) be located at the lower end of gear internal gear group (23) and diameter is more than most Big gear internal gear (23a)；When the stick group (25) does not stop gear internal gear group (23) and return pulley (6), gear Internal gear group (23) and return pulley (6) rise simultaneously, and gear internal gear (23a) and gear external gear (24a) are corresponded and coordinated, bottom Wheel (6) holds the gear external gear (24a) of foot from bottom；When the stick group (25) stops return pulley (6) or any shelves During internal gear (23a) of position, the gear internal gear (23a) not being blocked rises and gear external gear (24a) cooperation, undermost shelves Position internal gear (23a) do not drive corresponding to gear external gear (24a) only hold the gear external gear (24a) of last layer.

A kind of 4. training cycling safeguard structure according to claim 1 or 2 or 3, it is characterised in that：The stick Group (25) includes some sticks (25a), the stick (25a) include straight-bar (71) and be arranged on straight-bar (71) one end partly Circular arc bar (72), the middle part of the straight-bar (71) set rotating shaft (73), the semi arch on the catch bar arranged from top to bottom (22a) The radius of bar (72) is set from small to large.

A kind of 5. training cycling safeguard structure according to claim 1 or 2 or 3, it is characterised in that：The catch bar Some locating dowels (51) are provided with (22a), the locating dowel (51) is arranged in loose slot (53) simultaneously with unification spring (52) Spacing by a door (54) installation, the sphere end of the locating dowel (51) is stretched out from the opening at the middle part of door (54), described fixed Position post (51) mutually blocks cooperation with the positioning hole (55) on gear internal gear (23a).

A kind of 6. training cycling safeguard structure according to claim 4, it is characterised in that：The catch bar (22a) On be provided with some locating dowels (51), the locating dowel (51) is arranged in loose slot (53) with unification spring (52) and by a gear Lid (54) installation is spacing, and the sphere end of the locating dowel (51) is stretched out from the opening at the middle part of door (54), the locating dowel (51) cooperation is mutually blocked with the positioning hole (55) on gear internal gear (23a).