CN203819431U - Folding and unfolding device of portable electric scooter - Google Patents

Abstract

The folding and unfolding device of the portable electric scooter includes a front frame and a pedal. The lower end of the front frame is vertically provided with a rotating shaft. A fast folding mechanism, and a locking structure is correspondingly provided between the rear end of the pedal and the upper end of the front frame. The utility model has a simple structure and a reasonable design. It is upgraded and improved on the existing electric scooter used for short-distance and ultra-short-distance transportation. It realizes fast folding and novel and flexible control, and is easier to control and more practical. , the market prospect is broader.

Description

Folding and unfolding device for portable electric scooter

technical field

The utility model relates to a portable single-person vehicle, in particular to a folding and unfolding device for a portable electric scooter.

Background technique

Electric scooters are another new product form of skateboarding after traditional skateboards. Electric scooters are very energy efficient, charge quickly and have long range capabilities. The whole vehicle has beautiful appearance, convenient operation and safer driving. It is definitely a very suitable choice for friends who like life convenience, adding a little more fun to life.

Current electric scooters, especially electric scooters used by adults, are very advantageous in ultra-short-distance travel. Standing driving, small and light, suitable for traveling in small spaces. Compared with ordinary electric vehicles, the weight is already very light, and it can be carried more easily. It can even be stored in the trunk of a private car, for example, it can be taken out and used when there is a need for transportation after arriving at the destination. With the continuous improvement of the urban public transport system, many people have begun to consider using this light electric scooter for short-distance transportation from home to the bus station and transfer transportation in the public transportation system. However, although the current electric scooters are relatively light and have a folding function, the folding speed and folding method are still unsatisfactory, especially in the folding method. Generally, the entire body needs to be put down before folding, which is difficult for people in crowded environments. The operation of getting off caused great inconvenience, and it was not suitable for the rhythm of racing against time to enter and exit the bus system. In order to quickly and conveniently fold the electric scooter to be suitable for different environments, it is necessary to make corresponding improvements to the folding mechanism and the related control modes of the electric scooter.

Utility model content

In order to solve the deficiencies in the prior art, the utility model provides a folding and unfolding device for a portable electric scooter that is reasonable in design, simple in structure, easy to operate, and can be quickly folded without laying down the vehicle body.

In order to solve the above technical problems, the utility model adopts the following technical scheme: the folding and unfolding device of the portable electric scooter includes a front frame and a pedal, the lower end of the front frame is vertically provided with a rotating shaft, and the outside of the rotating shaft is connected by a bearing. Sleeve, there is a fast folding mechanism between the sleeve and the front end of the pedal, and a corresponding locking structure between the rear end of the pedal and the upper end of the front frame;

The fast folding mechanism includes two rollers, two driving rods, two connecting rods, two composite function hook plates, two fixing plates, a first connecting plate, a second connecting plate, a rotating seat and a limiter. The middle parts of the two drive rods are respectively hinged on the left and right sides of the front frame, the front ends of each drive rod are connected by a horizontal shaft, and the two rollers are respectively arranged at both ends of the horizontal shaft. The front end of the hook plate is respectively hinged on the left and right sides of the front frame, and the rear end of the composite function hook plate is provided with a hook portion, which is bent upwards with the opening facing forward, and the hinge point between the composite function hook plate and the front frame It is located at the rear and upper part of the hinge point between the driving rod and the front frame. The two ends of each connecting rod are respectively hinged with the rear end of the driving rod on the same side and the rear part of the composite function hook plate. The bottom surface of the front end of the plate is provided with a reinforcing plate connected to the rotating seat. The two fixed plates are parallel and set with a high front and a low inclination. The front end of a connecting plate is hinged between the front parts of the two fixed plates, the rear end of the second connecting plate is hinged on the rotating seat, the rear end of the first connecting plate is hinged with the front end of the second connecting plate, and the limit plate is set on the first connecting plate And located above the fixed plate, the left and right ends of the limit plate are respectively provided with a pin shaft that cooperates with the hook portion of the composite function hook plate on the same side; on the hinge shaft between the composite function hook plate and the front frame and the first connecting plate A torsion spring is arranged on the hinge shaft between the second connecting plate.

The locking structure includes a clamping plate, a locking lever, a tension spring and a rotating plate. One end of the clamping plate is arranged at one end of the central axis of the rear wheel, and the upper end of the clamping plate is provided with a hook engaged with the locking bar. The front end of the rotating plate is hinged on the On the front frame, the rear end of the rotating plate is perpendicular to and hinged to the lock lever, and the front and rear ends of the tension spring are respectively connected to the lock lever and the front frame. Below, the side of the front frame is provided with a gap for accommodating the up and down movement of the lock bar.

With the above technical solution, the folding and unfolding device of the portable electric scooter also includes the following technical features:

(1) There is a controller on the front frame, a stress sensor on the bottom of the pedal, and a potentiometer on the rear end of the pedal. The controller communicates with the stress sensor and the potential through the signal line device connection;

(2) There are two fine-tuning jackscrews threaded on the limit plate, and the two fine-tuning jackscrews correspond to press fit with the upper edge of a fixed plate;

(3) The lower end of the rotating shaft is provided with an electric front wheel, the rear end of the pedal is provided with a rear wheel, the front frame is provided with a rechargeable battery for powering the electric front wheel, and the rear wheel is provided with a cover for braking; There are headlights on the front side of the upper end of the frame, and an extension rod that can be stretched up and down in the front frame. There is a lift button on the upper end of the extension rod, and a foldable handlebar is installed on the left and right sides of the upper end of the extension rod. .

When riding a portable electric scooter, first unfold the handlebar in the folded state to the open state, and then press the lifting lock (the structure of the extension rod and the lifting button is similar to the structure of the telescopic rod in the trolley case) to pass the handlebar through The extension rod is pulled up to the desired length and locked. Pull the lock lever, the hook on the clamping plate will break away from the lock lever, the pedal will expand backward, and continue to expand under the action of the torsion spring on the hinge shaft between the first connecting plate and the second connecting plate, and at this time, it is fixed on the The limit plate on the first connection plate will be pushed against the two fixed plates, and the limit plate is provided with a fine-tuning screw to fine-tune the contact position between the limit plate and the fixed plate, that is, to adjust the front frame and the pedal The size of the angle between the plates. After fully unfolded, the hook portion of the composite function hook plate is separated from the pin shaft on the limit plate, and under the action of the torsion spring on the hinge shaft between the composite function hook plate and the front frame, the two hooks are connected by the connecting rod and the driving rod. The rollers are turned to the uppermost end so that they do not interfere with the riding operation. When the rider stands on the pedals, since a torsion spring is arranged in the hinge shaft between the first connecting plate and the second connecting plate, this will maintain the joint of the first connecting plate and the second connecting plate always There is a tendency to fall downwards, that is, the front end of the pedal has a tendency to fold upwards, but because the limiting plate fixed on the first connecting plate is in contact with the fixed plate, it just offsets the force of the torsion spring, so the pedal is limited Fold up.

Finally, when the rider stands on the pedal, the stress sensor located at the bottom of the pedal will sense the deformation of the pedal and transmit the signal to the controller, which is a signal that the scooter is in a riding state, The controller sends a signal to the rechargeable battery, and the rechargeable battery continuously supplies power to the electric front wheel, and the electric front wheel rotates to drive the rear wheel to enter the riding state. When deceleration is required, the rider steps on the cover, and the cover will first contact the potentiometer. After the potentiometer is triggered, a signal is sent to the controller, and the controller then sends a power-off signal to cut off the power supply to the electric front wheels, and continue to step on the cover When the cover is closed, the cover will rub against the rear wheels, thereby reducing the speed of the vehicle. When the vehicle speed is too low, stop stepping on the cover, thereby stop triggering the potentiometer, the controller will control and restore the power supply to the electric front wheels, and the vehicle speed will slowly rise. When parking, the cyclist first slows down to a certain low speed, and then jumps off from the pedal. The electric front wheels are no longer driven electrically, even when turning passively, because the stress sensors located at the bottom of the footboards no longer send out control signals.

When entering and exiting some places that are inconvenient to ride, such as the public transportation system, the electric scooter can be dragged like a suitcase, and the electric scooter will enter the folding carrying mode at this time. The specific folding process is: step on the horizontal shaft between the two rollers with your feet, and the driving rods at both ends of the horizontal shaft will drive the connecting rod to push the composite function hook plate to rotate upwards. At this moment, the front frame of the scooter must be turned into 90 degrees with the pedals (i.e. return to the center), and the composite function hook plate will contact and push the pin on the limit plate. The limiting plate will take the first connecting plate, and the first connecting plate will drive the second connecting plate hinged thereto to move upward. After the first connecting plate and the second connecting plate are folded, they will drive the rotating seat to rotate, thereby driving the pedals to rotate and fold upwards. The clamping plate located on the central axis of the rear wheel pushes the locking rod forward after the pedal is folded, and overcomes the force of the tension spring, and the locking rod moves downward so that the hook is just in contact with the locking rod to complete the locking lock. end. At this time, at the same time, the hook portion on the composite function hook plate will also hook the pin shaft on the limit plate to keep the position of the driving rod and the ground contact position of the two rollers. The driving handle drags the utility model car as a suitcase.

In addition, when the driver steps on the pedal, the stress sensor detects the deformation of the pedal and transmits the signal to the controller; when the driver starts to push the scooter forward with one foot on the ground, the electric front wheel The brushless motor rotates all round, and the in-wheel Hall sensor can measure the motor rotation signal and transmit the signal to the controller. When the controller receives these two signals, it starts to drive the front wheel hub motor to rotate. Since the maximum speed of the scooter itself is not fast, and the acceleration is relatively slow, after the electric drive, the speed gradually reaches the maximum. When the driver steps on the cover, the cover can contact and rub against the rear wheel to play a braking role. At the same time, the cover triggers the potentiometer to give the controller a signal to cut off the driving force of the hub motor of the electric front wheel. The speed of the vehicle begins to slow down, and when the speed of the vehicle decreases, if the driver does not continue to step on the cover, the speed of the vehicle will rise again. Because the electric front wheel rotates and the pedals are deformed; and when the vehicle speed decreases, the driver jumps off the sliding pedals, and the deformation of the pedals disappears. The controller controls the disappearance of the drive force of the hub motors of the electric front wheels. When the scooter is in the carrying mode, the electric front wheel is likely to turn. This design is to prevent the electric scooter from being out of control when the electric front wheel is turned by mistake when the pedal is folded.

The main design idea of the utility model is exactly that the vehicle body can fold the pedals under the premise of not putting down, and requires fast completion of the folding simultaneously. Since the weight of the car is different for people with different physiques, it needs to provide a carrying mode similar to a trolley suitcase after folding to facilitate transportation when not using the riding mode. The large stroke and more convenient telescopic extension rod also adopts a one-button pull-out and storage similar to a trolley suitcase. If there are handlebars and handbrakes on the handlebars, it will greatly affect the use effect. Therefore, these functions are replaced by the electric vehicle control mode.

The utility model has a simple structure and a reasonable design. It is upgraded and improved on the existing electric scooter used for short-distance and ultra-short-distance transportation. It realizes fast folding and novel and flexible control, and is easier to control and more practical. , the market prospect is broader.

Description of drawings

Fig. 1 is a three-dimensional structural schematic diagram of the utility model in a folded state;

Fig. 2 is a structural schematic diagram of the quick folding mechanism of the utility model in the folded state;

Fig. 3 is a schematic diagram of the three-dimensional structure of the utility model in the unfolded state;

Fig. 4 is a structural schematic diagram of the quick folding mechanism of the utility model in the unfolded state.

Detailed ways

As shown in Figure 1, Figure 2, Figure 3 and Figure 4, the portable electric scooter includes a front frame 1 and a pedal 2, the lower end of the front frame 1 is vertically provided with a rotating shaft, and the outside of the rotating shaft is connected with a sleeve through a bearing 3. The lower end of the rotating shaft is provided with an electric front wheel 4, the rear end of the pedal 2 is provided with a rear wheel 5, a quick folding mechanism is provided between the casing 3 and the front end of the pedal 2, and the rear end of the pedal 2 is connected to the front frame 1. A locking structure is correspondingly provided between the upper ends. The front frame 1 is provided with a rechargeable battery 6 for powering the electric front wheel 4. The rear wheel 5 is provided with a casing 7 for braking. The quick folding mechanism and the locking structure together constitute the folding and unfolding device of the present invention.

The front frame 1 is provided with a controller 8, the bottom of the pedal 2 is provided with a stress sensor 9, and the rear end of the pedal 2 is provided with a potentiometer 10 which is in contact with the cover 7, and the controller 8 communicates with the The strain sensor 9 is connected to a potentiometer 10 .

The front side of the front vehicle frame 1 upper end is provided with a headlight 11, and the front vehicle frame 1 is provided with an extension rod 12 that can be extended and retracted up and down. A foldable handlebar 14 is provided.

The quick folding mechanism includes two rollers 15, two driving rods 16, two connecting rods 17, two composite function hook plates 18, two fixing plates 19, a first connecting plate 20, a second connecting plate 21, a Rotating seat 22 and a limit plate 23, the middle part of two drive rods 16 are respectively hinged on the left side and the right side of front frame 1, the front end of each drive rod 16 is connected by a horizontal shaft 24, and two rollers 15 are respectively Located at both ends of the horizontal shaft 24, the front ends of the two composite function hook plates 18 are respectively hinged on the left and right sides of the front frame 1, and the rear ends of the composite function hook plates 18 are provided with hooks 33, and the hooks 33 are upward Bending and the opening facing forward, the hinge point of the composite function hook plate 18 and the front frame 1 is located at the rear upper part of the hinge point between the drive rod 16 and the front frame 1, and the two ends of each connecting rod 17 are connected with the drive rod on the same side respectively. 16 rear ends and composite function hook plate 18 rear portions are hinged, and rotating seat 22 is fixedly located at pedal 2 front ends, and pedal 2 front end bottom surfaces are provided with the reinforcing plate 31 that is connected with rotating seat 22, and two fixed plates 19 are parallel and parallel The front is high and the rear is low, and the front ends of the two fixed plates 19 are fixedly connected to the casing 3, the rear ends of the two fixed plates 19 are hinged with the rotating seat 22, and the front ends of the first connecting plate 20 are hinged between the front parts of the two fixed plates 19. Between, the rear end of the second connecting plate 21 is hinged on the rotating seat 22, the rear end of the first connecting plate 20 is hinged with the front end of the second connecting plate 21, and the limiting plate 23 is arranged on the first connecting plate 20 and is located above the fixed plate 19 , the left and right ends of the limit plate 23 are respectively provided with a pin shaft 25 that cooperates with the hook portion 33 of the composite function hook plate 18 on the same side; the hinge shaft between the composite function hook plate 18 and the front frame 1 and the first connection A torsion spring is provided on the hinge shaft between the plate 20 and the second connecting plate 21 (these two torsion springs are not shown in the figure).

Two fine-tuning jackscrews 26 are threadedly connected to the limiting plate 23 , and the two fine-tuning jackscrews 26 correspond to press fit with the upper edge of a fixed plate 19 respectively.

The locking structure comprises a clamping plate 27, a locking lever 28, a tension spring 29 and a rotating plate 30. One end of the clamping plate 27 is arranged on one end of the central axis of the rear wheel 5, and the upper end of the clamping plate 27 is provided with a grab hook which is engaged with the locking lever 28. 32. The front end of the rotating plate 30 is hinged on the front frame 1, the rear end of the rotating plate 30 is vertical and hinged to the lock bar 28, the front and rear ends of the extension spring 29 are respectively connected with the lock bar 28 and the front frame 1, and the extension spring 29 is connected to the front frame 1. The connection point of the vehicle frame 1 is located below the hinge point between the rotating plate 30 and the front vehicle frame 1 , and the side of the front vehicle frame 1 is provided with a gap for accommodating the movement of the locking bar 28 up and down.

When riding a portable electric scooter, first unfold the handlebar 14 in the folded state to the open state, and then press the lifting lock (the structure of the extension rod 12 and the lifting button 13 is similar to the structure of the telescopic rod in the trolley case) The handlebar 14 is pulled up to a suitable length through the extension rod 12 and locked. Pull the lock lever 28, the hook 32 on the clamping plate 27 is disengaged from the lock lever 28, the pedal 2 is unfolded backward, under the action of the torsion spring on the hinge shaft between the first connecting plate 20 and the second connecting plate 21 Continue to expand, and now the limiting plate 23 fixed on the first connecting plate 20 will be supported on the two fixing plates 19, and the limiting plate 23 is provided with a fine-tuning screw 26 that can be fine-tuned with the limiting plate 23 and the fixing plate 19. The contact position between, that is to adjust the angle between the front frame 1 and the pedal 2. After fully unfolding, the hook portion 33 of the composite function hook plate 18 breaks away from the pin shaft 25 on the limit plate 23, and under the action of the torsion spring on the hinge shaft between the composite function hook plate 18 and the front frame 1, the hook portion 33 passes through the connecting rod. 17 and driving rod 16 rotate two rollers 15 to the uppermost end, so as not to affect riding operation. When the rider stands on the pedal 2, since a torsion spring is arranged in the hinge shaft between the first connecting plate 20 and the second connecting plate 21, this will keep the first connecting plate 20 and the second connecting plate The joint of 21 always has a tendency to fall downwards, that is, the front end of the pedal 2 has a tendency to fold upwards, but because the limiting plate 23 fixed on the first connecting plate 20 is in contact with the fixed plate 19, it is just in contact with the torsion spring. The active forces are counteracted, so the restraint pedal 2 folds upwards.

Finally, when the rider stands on the pedal 2, the stress sensor 9 located at the bottom of the pedal 2 will sense the deformation of the pedal 2 and transmit the signal to the controller 8, which indicates that the scooter is riding. The signal of the running state, the controller 8 sends a signal to the rechargeable battery 6, the rechargeable battery 6 continues to supply power to the electric front wheel 4, and the electric front wheel 4 rotates to drive the rear wheel 5 to enter the riding state. When deceleration is required, the cyclist steps on the cover 7, and the cover 7 will first contact the potentiometer 10. After the potentiometer 10 is triggered, it will send a signal to the controller 8, and the controller 8 will send a power-off signal to cut off the motor. Wheel 4 supplies power, and after continuing to step on casing 7, casing 7 will contact friction with trailing wheel 5, thereby reduces the speed of a vehicle. When the speed of a vehicle is too low, stop stepping on the casing 7, thereby stop triggering the potentiometer 10, the controller 8 will control and restore the power supply of the electric front wheel 4, and the speed of the vehicle will slowly rise. When parking, the cyclist first decelerates to a certain low speed and then jumps off from the pedal 2 . Because the stress sensor 9 located at the bottom of the pedal 2 no longer sends a control signal, the electric front wheel 4 can no longer be electrically driven even when passively rotating.

When entering and exiting some places that are inconvenient to ride, such as the public transportation system, the electric scooter can be dragged like a suitcase, and the electric scooter will enter the folding carrying mode at this time. Concrete folding process is: step on the horizontal shaft 24 between two rollers 15 with foot, and the driving rod 16 at the two ends of the horizontal shaft 24 will drive the connecting rod 17 to push the composite function hook plate 18 to rotate upwards. Now must the front vehicle frame 1 of scooter and pedal 2 become 90 degrees (promptly return to positive), the composite function hook plate 18 will contact and promote the bearing pin 25 that is positioned on the limit plate 23. The limiting plate 23 will carry the first connecting plate 20, and the first connecting plate 20 will drive the second connecting plate 21 hinged thereto to move upward. After the first connecting plate 20 and the second connecting plate 21 are folded, the rotating base 22 will be driven to rotate, thereby driving the pedal 2 to rotate and fold upwards. The clamping plate 27 positioned on the central axis of the rear wheel 5 will push the lock bar 28 forward after the pedal 2 is folded, overcome the active force of the extension spring 29, and the lock bar 28 moves downward so that the grab 32 is just in time with the lock bar 28. Locking and locking can be completed by connecting and cooperating. At this time, the hook portion 33 on the composite function hook plate 18 will also hook the pin shaft 25 on the limit plate 23 to keep the position of the driving rod 16 and the ground contact position of the two rollers 15, and the two rollers 15 are just in position. At the lowest end, the utility model car can be towed like a suitcase by towing the handlebar 14.

In addition, when the driver steps on the pedal 2, the stress sensor 9 detects the deformation of the pedal 2, and sends the signal to the controller 8; when the driver starts to push the scooter forward with one foot on the ground, the motor The brushless motor on the front wheel 4 rotates in all directions, and the hall sensor in the wheel can measure the relevant motor rotation signal, and the signal is delivered to the controller 8. Controller 8 starts to drive the front wheel hub motor to rotate when receiving these two signals. Since the maximum speed of the scooter itself is not fast, and the acceleration is relatively slow, after the electric drive, the speed gradually reaches the maximum. When the driver steps on the cover 7, the cover 7 can contact and rub against the rear wheel 5 to play a braking role. At the same time, the cover 7 triggers the potentiometer 10 to give the controller 8 a drive to cut off the hub motor of the electric front wheel 4. force signal. Speed of a motor vehicle starts to slow down, and after speed of a motor vehicle reduces, if the driver does not continue to step on casing 7, speed of a motor vehicle will pick up again. Because the electric front wheel 4 rotates and the pedal 2 deforms; and when the speed of the vehicle is reduced again, the driver jumps off the pedal 2, and the deformation of the pedal 2 disappears. The controller 8 controls the in-wheel motor driving force of the electric front wheel 4 to disappear. When the scooter is in the carrying mode, the electric front wheel 4 is likely to turn. This design is to prevent the electric scooter from being out of control when the electric front wheel 4 is turned by mistake when the pedal 2 is folded.

The main design idea of the portable electric scooter is that the body should be able to fold the pedal 2 without putting it down, and at the same time, it is required to complete the folding quickly. Since the weight of the car is different for people with different physiques, it needs to provide a carrying mode similar to a trolley suitcase after folding to facilitate transportation when not using the riding mode. The large-stroke and more convenient telescopic extension rod 12 also adopts a one-key pull-out and storage similar to a trolley suitcase. If the handlebar 14 has a handlebar and a handbrake, it will greatly affect the use effect. Therefore, these functions are replaced by the electric vehicle control mode.

This embodiment does not impose any formal restrictions on the shape, material, structure, etc. of the utility model. Any simple modifications, equivalent changes and modifications made to the above embodiments according to the technical essence of the utility model belong to the technology of the utility model. protection scope of the program.

Claims (2)

1. A folding and unfolding device for a portable electric scooter, including a front frame and a pedal, characterized in that: the lower end of the front frame is vertically provided with a rotating shaft, and a casing is connected to the outside of the rotating shaft through a bearing, and the casing and the pedal There is a fast folding mechanism between the front ends of the board, and a corresponding locking structure between the rear end of the pedal and the upper end of the front frame; The fast folding mechanism includes two rollers, two driving rods, two connecting rods, two composite function hook plates, two fixing plates, a first connecting plate, a second connecting plate, a rotating seat and a limiter. The middle parts of the two drive rods are respectively hinged on the left and right sides of the front frame, the front ends of each drive rod are connected by a horizontal shaft, and the two rollers are respectively arranged at both ends of the horizontal shaft. The front end of the hook plate is respectively hinged on the left and right sides of the front frame, and the rear end of the composite function hook plate is provided with a hook portion, which is bent upwards with the opening facing forward, and the hinge point between the composite function hook plate and the front frame It is located at the rear and upper part of the hinge point between the driving rod and the front frame. The two ends of each connecting rod are respectively hinged with the rear end of the driving rod on the same side and the rear part of the composite function hook plate. The bottom surface of the front end of the plate is provided with a reinforcing plate connected to the rotating seat. The two fixed plates are parallel and set with a high front and a low inclination. The front end of a connecting plate is hinged between the front parts of the two fixed plates, the rear end of the second connecting plate is hinged on the rotating seat, the rear end of the first connecting plate is hinged with the front end of the second connecting plate, and the limit plate is set on the first connecting plate And located above the fixed plate, the left and right ends of the limit plate are respectively provided with a pin shaft that cooperates with the hook portion of the composite function hook plate on the same side; on the hinge shaft between the composite function hook plate and the front frame and the first connecting plate A torsion spring is arranged on the hinge shaft between the second connecting plate. 2. The folding and unfolding device of the portable electric scooter according to claim 1, wherein the locking structure includes a clamping plate, a locking lever, a tension spring and a rotating plate, and one end of the clamping plate is arranged on the central axis of the rear wheel At one end, the upper end of the clamping plate is provided with a hook that snaps and fits with the lock bar. The front end of the turn plate is hinged on the front frame, the rear end of the turn plate is perpendicular to the lock bar and is hinged, and the front and rear ends of the tension spring are respectively connected to the lock bar and the front frame. The frame is connected, the connection point between the extension spring and the front frame is located below the hinge point of the rotating plate and the front frame, and the side of the front frame is provided with a gap for accommodating the up and down movement of the lock bar.