KR20210055412A - Apparatus for going up and down stairs - Google Patents

Abstract

The present invention relates to a stair ascending device for ascending and descending stairs in a state in which a wheelchair is seated and supported, and more particularly, a support frame in which a wheel of a wheelchair is seated and supported at an upper portion, and a transfer roller is provided at a lower portion; A caterpillar located under the support frame, the other side rotatably connected with respect to the lower one side of the support frame; A first actuator connected between the support frame and the caterpillar to adjust a rotation angle of the caterpillar; A transfer angle adjusting means positioned on both sides of the lower portion of the support frame, and one side is rotatably connected with respect to the other lower side of the support frame; A second actuator connected between the support frame and the transfer angle control means to adjust the rotation angle of the transfer angle control means; And a guide frame formed upward from one side of the support frame and provided with a handle for gripping a protector and a control unit for controlling the caterpillar, the first actuator, and the second actuator. It relates to the device.

Description

Stair climbing device {APPARATUS FOR GOING UP AND DOWN STAIRS}

The present invention relates to a stair climbing device for up and down stairs with a wheelchair, and in particular, to an electric stair climbing device configured to safely and easily lift a wheelchair even by a guardian alone.

In general, a wheelchair is a means of movement formed so that a person who is not free to move can move while sitting, and consists of a seat fixed to a pipe-shaped frame, a front wheel, a parking wheel, a steering wheel, etc., and a parental control type and user operation It can be distinguished by type, and it can also be divided into a power driving type and a guardian or user driving type. All of these wheelchairs are driven on a road or indoors by driving a front wheel and a parking wheel while carrying a single person. On the other hand, the parking wheel is formed in a large size, but the front wheel is usually formed of a wheel having a small diameter in order to improve the steering performance during driving.

Therefore, if there is an obstacle such as a barrier or step while driving on the road or indoors, there is a problem that it takes a lot of effort to get on and over it.In particular, when encountering an obstacle such as a staircase, the wheelchair may climb or descend. There is a problem that there is no.

Meanwhile, in order to solve the problem that a wheelchair cannot climb or descend stairs as described above, in public facilities such as subways, a separate slope is constructed on the stairs or a wheelchair lift is manufactured to solve this problem. However, it is a reality that constructing the above-described structure individually when there is a structure such as a staircase not only incurs a lot of cost, but also does not have such facilities in general facilities other than public facilities.

Accordingly, research on a more economical and safe ascending device for raising and lowering the stairs of a wheelchair is being conducted steadily.

(0001) Domestic registration patent No. 10-0992110 (0002) Domestic registered patent No. 10-1233585

The technical problem to be solved by the present invention is to provide an economical and convenient stair climbing device compared to the prior art.

Another technical problem to be solved by the present invention is to provide a stair climbing device configured to be safely and easily used by a guardian alone.

The present inventors stair climbing device for achieving the above technical problem relates to a stair climbing device for climbing stairs while the wheelchair is seated and supported, wherein the wheel of the wheelchair is seated and supported at the upper part, and a support roller is provided at the lower part. frame; A caterpillar located under the support frame, the other side rotatably connected with respect to the lower one side of the support frame; A first actuator connected between the support frame and the caterpillar to adjust a rotation angle of the caterpillar; A transfer angle adjusting means positioned on both sides of the lower portion of the support frame, and one side is rotatably connected with respect to the other lower side of the support frame; A second actuator connected between the support frame and the transfer angle control means to adjust the rotation angle of the transfer angle control means; And a guide frame formed upward from one side of the support frame and provided with a handle for gripping a protector and a control unit for controlling the caterpillar, the first actuator, and the second actuator. It is done.

In addition, it is characterized in that the separation prevention frame is further provided on both sides of the upper side of the support frame, respectively, to prevent the side separation of the wheelchair.

In addition, the guide frame is characterized in that further provided with a support means for supporting the rear frame of the wheelchair so that the wheelchair seated and supported by the support frame does not deviate forward from the support frame.

In addition, the guide frame is characterized in that the folding is coupled to the upper portion of the support frame.

In addition, the transfer roller is characterized in that it is formed on the lower side of the other side of the support frame and one side of the transfer angle adjusting means.

The present invention described above has the following effects.

First, by adjusting the rotation angle through the first actuator between the support frame and the caterpillar and the rotation angle through the second actuator between the caterpillar and the transfer angle adjustment means, it is easy to adjust the angle when going up and down stairs, as well as the support on which the wheelchair is seated. The safety can be increased by maintaining the horizontal state of the frame.

In addition, it is possible to solve the problem that the support frame sharply collides with the floor surface due to movement of the center of gravity due to the inclination angle of the caterpillar at the top and bottom of the stairs through the transfer angle adjusting means.

In addition, the separation prevention frame and the support means can prevent the side and front separation of the wheelchair, so that safety can be further improved.

In addition, it is possible to improve storage by configuring the guide frame in a foldable.

In addition, by providing the transfer roller in the support frame and the transfer angle control means, it is easy to move the position on the level, and even when the stairs are elevated, the contact with the floor surface is smoothly guided by the transfer roller provided in the transfer angle control means. Impact strength can be reduced every time it comes into contact with the surface.

In addition, since there is no need to install separate facilities such as a wheelchair lift for raising and lowering the stairs of a wheelchair wherever there are stairs, it is solved by only providing the stair climbing device according to the present invention, so that related costs can be greatly reduced.

In addition, it is possible to further improve the quality of life for the disabled through the stair climbing device.

1 is a front perspective view according to an embodiment of a staircase ascending device according to the present invention,
Figure 2 is a rear perspective view of Figure 1,
Figure 3 is a side view of Figure 1,
4 and 5 are a bottom perspective view of the stair climbing device according to the present invention in a tilting state,
6 is a side view of the stair climbing device according to the present invention in a tilting state;
7 is a conceptual diagram showing a wheelchair movement state using a stair climbing device according to the present invention,
8 to 24 are conceptual diagrams showing a stair elevation state of the stair climbing device according to the present invention.

Hereinafter, some embodiments of the present invention will be described in detail through exemplary drawings. In adding reference numerals to elements of each drawing, it should be noted that the same elements are assigned the same numerals as possible, even if they are indicated on different drawings. In addition, in describing the embodiments of the present invention, if it is determined that a detailed description of a related known configuration or function obstructs the understanding of the embodiments of the present invention, the detailed description thereof will be omitted.

In addition, in describing the constituent elements of the embodiments of the present invention, terms such as first, second, A, B, (a), and (b) may be used. These terms are for distinguishing the constituent element from other constituent elements, and the nature, order, or order of the constituent element is not limited by the term. When a component is described as being "connected", "coupled" or "connected" to another component, the component may be directly connected or connected to that other component, but another component between each component It should be understood that may be “connected”, “coupled” or “connected”.

First, the present invention relates to a stair climbing device that is provided in a place where there is a staircase for a guardian driving a wheelchair so that the guardian alone can easily move up and down the stairs of the wheelchair.

That is, there is no need for a separate facility such as a wheelchair lift installed on the side of the stairs in the lengthwise direction of the stairs as in the related art, and by using the stair climbing device according to the present invention, a wheelchair can be safely and easily lifted and lowered by a guardian alone.

The term'wheelchair' described in this specification can be understood as a state in which a disabled person is seated or a state in which only a wheelchair is present without a disabled person, and the wheelchair corresponds to all types of known wheelchairs.

In addition, for convenience of explanation, the direction in which the guide frame is located relative to the middle part of the support frame is referred to as one side (part), one end, and rear, and the opposite direction is referred to as the other side (part), the other end, and the front.

In addition, the present invention operates by receiving power, and the power is supplied through a battery mounted in the stair climbing device. It is preferable to use a rechargeable battery as the battery.

Hereinafter, the basic structure of the stair climbing device according to the present invention will be first described with reference to the drawings.

1 is a front perspective view according to an embodiment of a stair climbing device according to the present invention, FIG. 2 is a rear perspective view of FIG. 1, FIG. 3 is a side view of FIG. 1, and FIGS. 4 and 5 are stairs according to the present invention. It is a bottom perspective view of the ascending device in a tilted state, FIG. 6 is a side view of the stair ascending device according to the present invention in a tilted state, and FIG. 7 is a conceptual diagram showing a wheelchair movement state using the stair ascending device according to the present invention.

Referring to Figures 1 to 7, the inventors stair climbing device is a support frame (10), guide frame (20), caterpillar (30), first and second actuators (40, 50), transfer angle adjustment means (60) And it is configured to include a transfer roller (70).

The support frame 10 is for seating and supporting the wheelchair 1, and guides the wheelchair 1 to the upper portion to seat and support the wheelchair 1 located at the top. For the seating of the wheelchair 1, the support frame 10 is provided with at least one hole (not shown) corresponding to the positions of the wheels and the wheels of the wheelchair 1. When the wheel is inserted into such a hole, the seating power is increased. At this time, the hole for seating the rear wheel of the wheelchair 1 is formed in the same direction as the moving direction of the rear wheel of the wheelchair 1, and the hole for seating the front wheel of the wheelchair 1 is the moving direction of the rear wheel of the wheelchair 1 It may be formed in a direction orthogonal to and to seat the front wheel of the fitchair. This has the effect of preventing the wheelchair 1 seated on the support frame 10 from being separated from the front of the support frame 10 only by the seating and supporting force of the wheel of the wheelchair 1 inserted into the hole of the support frame 10.

On the other hand, on both sides of the upper side of the support frame 10 are further provided with a separation prevention frame 11 for preventing the side separation of the wheelchair (1), respectively. As described above, the separation of the wheelchair 1 can be prevented just by being inserted and seated in the hole formed in the support frame 10, but separation is prevented on both sides of the upper side of the support frame 10 in order to prepare for a safety accident. It is preferable to further include the frame 11. In addition, although not shown, a locking device for locking the wheel of the wheelchair 1 may be configured on the support frame 10 itself.

At the rear of the support frame 10 and the separation prevention frame 11, a prevention piece (not shown) formed inclined upward may be provided, and the support frame is guided from the front of the support frame 10 through the prevention piece. It is possible to guide the wheelchair (1) positioned at the top of the (10) to prevent separation to the rear of the support frame (10), the wheelchair (1) to be seated in the correct position at the top of the support frame (10). Of course, it is possible to sufficiently prevent the wheelchair 1 from being separated from the rear of the support frame 10 by only the configuration of the guide frame 20 to be described later.

The guide frame 20 is formed upward from one rear side of the support frame 10. The upper part of the guide frame 20 is formed with a handle 21 that can be gripped by the protector by hand. Referring to FIG. 7, the handle 21 is illustrated in a form extending from the top of the guide frame 20 in both horizontal directions. The handle 21 is configured so that the guardian grips the stair climbing device of the present invention to safely and easily perform the stair elevation of the wheelchair 1, and the structure can be applied differently according to the use state of the guardian, and only in the shape shown. It is not desirable to limit.

The guide frame 20 is provided with a control unit 22. The control unit 22 is located above the guide frame 20, and on the same horizontal line as the handle 21 on which the guardian's arm is located, that is, the handle ( It is preferably located between 21) and the handle (21). The caterpillar 30 and the first and second actuators 40 and 60 to be described later may be controlled through the control unit 22. To this end, at least a plurality of control buttons may be provided, and a display unit capable of guiding a user by displaying a control state may be configured together. In addition, a dangerous situation notification unit such as a speaker may be additionally provided to guide the guardian in the event of an abnormal operation or a dangerous situation.

In addition, referring to FIG. 7, the guide frame 20 has a support for supporting the rear frame of the wheelchair 1 so that the wheelchair 1 seated and supported on the support frame 10 is not separated from the support frame 10 forward. Means 23 may be further provided. Although not shown in detail, the support means 23 are formed on both upper sides of the guide frame 20, and when the wheelchair 1 is positioned above the support frame 10, the wheelchair 1 is moved in the horizontal direction to the outside of both sides, and then the wheelchair 1 After being positioned in the correct position, it moves back to the inner horizontal direction to support the frame connected to the handle 21 of the wheelchair (1). To this end, a hook-shaped support member (not shown in the drawing) for supporting the frame of the wheelchair 1 is provided in front of the support means 23. In addition, a pressure adjusting means (not shown in the drawing) for pressing the frame of the wheelchair 1 located in the support member by pulling the support member rearward is provided. As the pressure adjusting means rotates forward/reversely, the body of the supporting member connected thereto moves forward and backward, pressing the frame of the wheelchair 1 or releasing the pressurized state. In addition, although not shown, the support means 23 may be configured to move up and down along the guide frame 20, through which the height of the support means 23 can be adjusted according to the frame position of the wheelchair 1 .

On the other hand, although not shown, the guide frame 20 can be installed in a foldable manner so as to be folded in the upper direction of the support frame 10, and the storage of the stair climbing device can be improved during the folding installation. The folding installation can be configured by applying various known techniques, and since the folding technique itself is a known technique, a detailed description thereof will be omitted.

The caterpillar 30 is located under the support frame 10, and the other side of the caterpillar 30 is rotatably connected with respect to the lower one side of the support frame 10. The outer side of the caterpillar 30 is connected by a rubber belt, and support jaws are formed at regular intervals. When the belt is made of rubber and the support jaws are formed, it is possible to prevent slipping by increasing the frictional force and supportive force when climbing stairs. The caterpillar 30 is connected to the driving unit, and the driving unit (not shown in the drawing) is connected to the control unit 22 to rotate forward and backward.

The first actuator 40 may use a linear motor controlled through the control unit 22, and is connected between the central portion of one side of the support frame 10 and the central portion of the other side of the caterpillar 30. For convenience of explanation, as shown in FIG. 3, the operating state of the first actuator 40 and the second actuator 60 to be described later in the basic posture before ascending and descending the stairs is expressed as'compression', and as shown in FIG. The operating state of the first and second actuators 40 and 60 when the caterpillar 30 and the transfer angle adjusting means 50 to be described later are in a tilted state is expressed as'expansion'. The rotation angle of the caterpillar 30 may be adjusted by compression and expansion of the first actuator 40, and the rotation angle may vary according to the inclination angle of the stairs. In addition, the rotation angle of the caterpillar 30 is adjusted through the first actuator 40, but as a result, the caterpillar 30 is supported on the floor or stairs, so the first actuator 40 is It is used to maintain state. Maintaining the horizontal state of the support frame 10 serves to prevent the wheelchair 1 from being separated from the front of the support frame 10, so that the support frame 10 is maintained in a horizontal state or the front of the support frame 10 It is preferable to control the support frame 10 so as to maintain the inclined state at a predetermined angle by being lifted upward.

The transfer angle adjustment means 50 are respectively located on both lower sides of the support frame 10, and one side of the transfer angle control means 50 is rotatably connected with respect to the other lower side of the support frame 10. The transfer angle adjustment means 50 is used to adjust the elevation angle of the caterpillar 30 when climbing the stairs, and smooth contact between the floor surface and the caterpillar 30 so that a strong impact is not applied to the stair climbing device at the top and bottom of the stairs. It is used for

The second actuator 60 may also use a linear motor controlled through the control unit 22, and is composed of two, one on each side of the support frame 10. The second actuator 60 is connected between the other side of the lower side of the support frame 10 and one side of the transfer angle adjusting means 50. As described above, when the second actuator 60 is compressed, the transfer angle adjustment means 50 is positioned as shown in FIG. 3, and when the second actuator 60 is expanded, the transfer angle control means 50 is positioned as shown in FIG. 6. Of course, the tilting angle of the transfer angle adjusting means 50 may be further increased according to the inclination angle of the stairs. Two of the second actuators 60 operate identically, and the rotation angle of the transfer angle control means 50 can be adjusted by compression and expansion by the second actuator 60, and the transfer angle control means 50 The angle of rotation may also vary depending on the inclination angle of the stairs.

The conveying roller 70 is used for movement on a level surface of the stair climbing device according to the present invention. Although not shown, it may be installed at the lower four corners of the support frame 10, and a transfer roller 70 provided with a stopper so as not to move normally may be used. The position of the transfer roller 70 is not limited, but the transfer roller 70 is preferably formed under the other side of the support frame 10 and on one side of the transfer angle adjusting means 50. By configuring in this way, it is easy to move the position on the flat ground, as well as smoothly inducing contact with the floor surface by the transfer roller 70 provided in the transfer angle adjusting means 50 even when raising and lowering the stairs. It is possible to reduce the impact strength transmitted to the stairs climbing device in every city.

The operating state of the stair climbing device according to the present invention described above will be described in more detail based on the drawings. (See Figs. 1 to 7 together)

8 to 24 are conceptual diagrams showing a stair elevation state of the stair climbing device according to the present invention. In the drawings, the shape of the wheelchair 1 is omitted for convenience.

First, referring to FIG. 8, when climbing the stairs, the guardian positions the stairs in front of the stairs to use the stairs ascending device. At this time, the wheelchair 1 may be moved while being seated and supported on the upper part of the support frame 10, or the wheelchair 1 may be seated and supported on the upper part of the support frame 10 while being positioned in front of the stairs.

Thereafter, as shown in FIG. 9, the stair climbing device is moved to be close to the stairs.

Referring to FIG. 10, the second actuator 60 is expanded through the control unit 22 so that the inclination angle of the caterpillar 30 is adjusted according to the inclination of the first staircase located below. At this time, when only the second actuator 60 is inflated, one side of the caterpillar 30 is lifted upward and only the front of the support frame 10 is lifted upward, so the first actuator 40 is also expanded to expand the support frame 10. ) It is preferable to adjust to maintain a horizontal state or a state in which the front of the support frame 10 is lifted upward by a predetermined angle. In the following description, it will be understood that the'horizontal state' includes both cases. 10 is a state in which one side of the transfer angle adjusting means 50 in which the transfer roller 70 is installed is in contact with the bottom of the stairs.

Thereafter, as shown in FIG. 11, when one side of the caterpillar 30 is supported by the corner of the first step, the second actuator 60 is compressed to lift one side of the transfer angle adjusting means 50.

In this state, when the caterpillar 30 is rotated forward through the control unit 22 as shown in FIG. 12, the caterpillar 30 is supported by the edge of the step, and the stair climbing device is transferred to the upper part of the step by the rotational force of the caterpillar 30.

As the stair climbing device is transferred to the top by the rotational force of the caterpillar 30, the inclination angle of the caterpillar 30 is slightly higher before the caterpillar 30 contacts the edge of the second staircase together with the edge of the first staircase. It needs to be adjusted. Accordingly, as shown in FIG. 13, the second actuator 60 is expanded through the control unit 22 so that one side of the transfer angle adjusting means 50 is supported on the upper surface of the first step.

The caterpillar 30 is continuously rotated forward, and when the caterpillar 30 is supported at the corners of the first and second steps at the same time, the second actuator is compressed again as shown in FIG. 14 to adjust the transfer angle. Raise one side of ).

Thereafter, the stair climbing device is transferred to the upper part of the stair by only the forward rotation of the caterpillar 30. At this time, as shown in FIG. 16, only the caterpillar 30 is rotated forward until it is transferred while the caterpillar 30 is simultaneously supported at the corners of the upper two steps.

As shown in FIG. 17 again, the caterpillar 30 is simultaneously supported on the upper two stair corners, and the second actuator 60 is again transferred to one side of the transfer angle cutting means before spanning only the uppermost one stair corner. It expands to be supported on the top surface of this staircase. The reason for this operation is that when the caterpillar 30 is supported only at the edge of one step, the center of gravity of the stair ascending device moves in the conveying direction, and one side of the support frame 10 and the caterpillar 30 is sharply on the top surface of the step. This is to prevent the impact transmitted to the stair climbing device while contacting.

Therefore, in a state in which the second actuator 60 is expanded as shown in FIG. 17, as shown in FIG. 18, the second actuator 60 is compressed in accordance with the rotational speed of the caterpillar 30 to compress the support frame 10 and the caterpillar. Induce (30) to gradually contact the top surface of the stairs. At this time, the first actuator 40 is also compressed so that the support frame 10 maintains a horizontal state.

19 is a state in which the stair ascending operation using the stair ascending device is completed. In other words, the first actuator 40 and the second actuator 60 are both compressed in the same way as before climbing the first stairs, and the caterpillar 30 is in a stopped state and only the transfer roller 70 is in a state of being stopped. It is in contact.

When going down the stairs again, the operation proceeds in the reverse order of the above-described operation.

When going down the stairs, since the wheelchair 1 may be separated from the front of the support frame 10 open, the first actuator 40 is slightly inflated to lift the front of the support frame 10 as shown in FIG. 20.

Subsequently, the operation is performed in the order of FIGS. 18, 17, and 16, and the description of the operation state will refer to the description of FIGS. 18, 17, and 16 described above.

As shown in FIG. 21, when descending the stairs, the caterpillar 30 rotates and descends while being supported by the corners of the stairs.

Thereafter, as shown in FIG. 22, when the other side of the caterpillar 30 starts to contact the bottom of the stairs, as shown in FIG. 23, the second actuator 60 is again transferred to one side of the transfer angle adjustment means 50. It expands so that it contacts the upper surface of the first step of the lower part. This is the same only as the state of FIG. 13 and the direction of rotation of the caterpillar 30 is different.

After that, when one side of the caterpillar 30 comes into contact with the bottom surface and the stop of the caterpillar 30 contacts only the edge of one step located at the bottom of the stairs, as shown in FIG. 24, the second actuator 60 is compressed and transferred again. One side of the angle adjustment means 50 is lifted.

Thereafter, before the other side of the caterpillar 30 passes through the edge of the last step and contacts the bottom surface, the second actuator 60 is expanded so that one side of the transfer angle adjusting means 50 contacts the bottom surface. This is the same only as the state of FIG. 10 and the direction of rotation of the caterpillar 30 is different.

Thereafter, both the first actuator 40 and the second actuator 60 are compressed to maintain the state before descending the first staircase, and the caterpillar 30 is stopped to complete the staircase descending operation. This may refer to the state of FIG. 9.

According to the present invention described above, it is possible to safely and easily transfer the stairs of the wheelchair 1 even by the guardian alone, and because there is no need to install separate facilities such as a conventional wheelchair 1 lift, cost can be greatly reduced. have.

In the above, even if all the constituent elements constituting the embodiments of the present invention have been described as being combined into one or operating in combination, the present invention is not necessarily limited to these embodiments. That is, within the scope of the object of the present invention, all the constituent elements may be selectively combined and operated in one or more. In addition, terms such as "include", "consist of" or "have" described above mean that the corresponding component may be present unless otherwise stated, excluding other components. It should not be construed as being able to further include other components. All terms, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art, unless otherwise defined. Terms generally used, such as terms defined in the dictionary, should be interpreted as being consistent with the meaning of the context of the related technology, and are not interpreted as ideal or excessively formal meanings unless explicitly defined in the present invention.

The above description is merely illustrative of the technical idea of the present invention, and those of ordinary skill in the art to which the present invention pertains will be able to make various modifications and variations without departing from the essential characteristics of the present invention. Accordingly, the embodiments posted in the present invention are not intended to limit the technical idea of the present invention, but to explain the technical idea, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be construed by the following claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present invention.

1: wheelchair
10: support frame 11: separation prevention frame
20: guide frame 21: handle
22: control unit 23: support means
30: caterpillar 40: first actuator
50: transfer angle adjustment means 60: second actuator
70: transfer roller

Claims (5)

It relates to a stair climbing device that moves up and down stairs while the wheelchair is seated and supported,
A support frame on which the wheel of the wheelchair is seated and supported at the upper part and provided with a transfer roller at the lower part;
A caterpillar located under the support frame, the other side rotatably connected with respect to the lower one side of the support frame;
A first actuator connected between the support frame and the caterpillar to adjust a rotation angle of the caterpillar;
A transfer angle adjusting means positioned on both sides of the lower portion of the support frame and having one side rotatably connected to the lower other side of the support frame;
A second actuator connected between the support frame and the transfer angle control means to adjust the rotation angle of the transfer angle control means; And
A guide frame formed in an upward direction from one side of the support frame and provided with a handle for gripping a protector and a control unit for controlling the caterpillar, the first actuator, and the second actuator;
Stair ascending device comprising a. The method of claim 1,
Stair climbing device further provided with a departure prevention frame for preventing the side separation of the wheelchair, respectively, on both sides of the upper portion of the support frame. The method of claim 1,
In the guide frame,
Stair climbing device further provided with support means for supporting the rear frame of the wheelchair so that the wheelchair seated on the support frame does not deviate forward from the support frame. The method of claim 1,
The guide frame is a stair ascending device, characterized in that coupled to the fold to be folded to the upper portion of the support frame. The method according to any one of claims 1 to 4,
The transfer roller,
Stair ascending device, characterized in that formed on the lower side of the other side of the support frame and one side of the transfer angle adjustment means.

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