阅读说明：本技术 带安全锁组件的人字梯 (Herringbone ladder with safety lock assembly ) 是由 谢建民 于 2021-07-28 设计创作，主要内容包括：本发明及一种带安全锁组件的人字梯,包括前梯架、后梯架、上踏板及定位杆,其特点是还包括安全锁组件,安全锁组件包括第一摆件、固定板、弹性组件、第二摆件及安装座；安装座安装在上踏板上,第一摆件转动的安装在安装座上,在第一摆件一侧设有把手,把手位于上踏板一侧,第二摆件转动的安装在安装座上,在第二摆件的一侧设有挂钩,第一摆件与第二摆件配合,第一摆件与第二摆件通过弹性组件连接,第一摆件摆动带动第二摆件摆动后定位,第二摆件摆动将挂钩锁扣在定位杆上；固定板安装在安装座上位于第一摆件及第二摆件外侧将第一摆件及第二摆件前后定位。其优点是打开人字梯后,能快捷的将人字梯钩锁定位,定位后的人字梯稳固,安全可靠。(The invention relates to a herringbone ladder with a safety lock assembly, which comprises a front ladder frame, a rear ladder frame, an upper pedal, a positioning rod and the safety lock assembly, wherein the safety lock assembly comprises a first swinging part, a fixed plate, an elastic assembly, a second swinging part and a mounting seat; the installation seat is installed on the upper pedal, the first swing part is rotatably installed on the installation seat, one side of the first swing part is provided with a handle which is positioned on one side of the upper pedal, the second swing part is rotatably installed on the installation seat, one side of the second swing part is provided with a hook, the first swing part is matched with the second swing part, the first swing part and the second swing part are connected through an elastic component, the first swing part swings to drive the second swing part to swing and then to be positioned, and the second swing part swings to lock the hook on the positioning rod; the fixed plate is arranged on the mounting seat and positioned outside the first swing part and the second swing part to position the first swing part and the second swing part in the front-back direction. The positioning device has the advantages that after the herringbone ladder is opened, the herringbone ladder hooks can be quickly positioned, and the positioned herringbone ladder is stable, safe and reliable.)

1. A herringbone ladder with a safety lock assembly comprises a front ladder frame, a rear ladder frame, an upper pedal (2) and a positioning rod (7), wherein the front ladder frame comprises two front ladder rods (1), and the rear ladder frame comprises two rear ladder rods (8); the two rear ladder bars (8) are respectively and rotatably arranged on the corresponding front ladder bars (1), the upper pedal (2) is rotatably arranged on the two front ladder bars (1), and the positioning rod (7) is arranged on the two rear ladder bars (8) and is positioned below the upper pedal (2); characterized by further comprising a safety lock assembly (6);

the safety lock assembly (6) comprises a first swinging part (61), a fixed plate (62), an elastic assembly (63), a second swinging part (65) and a mounting seat (64); the top of the mounting seat (64) is mounted on the upper pedal (2), the first swing part (61) is rotatably mounted on the mounting seat (64), a handle (611) is arranged on one side of the first swing part (61), the handle (611) is positioned on one side of the upper pedal (2), the second swing part (65) is rotatably mounted on the mounting seat (64) and is positioned on the other side of the first swing part (61), a hook (651) is arranged on one side of the second swing part (65), the other side of the first swing part (61) is matched with one side of the second swing part (65), the first swing part (61) and the second swing part (65) are connected through an elastic component (63), the first swing part (61) swings to drive the second swing part (65) to swing and then position, and the second swing part (65) swings to enable the hook (651) to fix the upper pedal (2) on the positioning rod lock catch (7); the fixing plate (62) is mounted on the mounting base (64) and located outside the first swing portion (61) and the second swing portion (65) to position the first swing portion (61) and the second swing portion (65) in a front-rear direction.

2. The ladder with the safety lock assembly as claimed in claim 1, wherein a first protrusion (615) is provided on the other side of the first swing member (61), a second protrusion (653), a first groove (656) and a second groove (657) are provided on one side of the second swing member (65), the second protrusion (653) is located above the hook (651), the first groove (656) is located between the second protrusion (653) and the hook (651), the second groove (657) is located above the second protrusion (653), the first protrusion (615) can abut against the first groove (656) and the second groove (657), respectively, and the first protrusion (615) swings to drive the second swing member (65) to swing.

3. The ladder with safety lock assembly according to claim 1, wherein a first through hole (641) is formed at the bottom of the mounting seat (64), a second through hole (621) is formed at the bottom of the fixing plate (62), and the positioning rod (7) can pass through the first through hole (641) and the second through hole (621) and is locked on the hook (651).

4. A ladder with a safety lock assembly according to claim 1, characterized in that a first catch (614) is provided on top of the first swing part (61), a second catch (654) is provided on top of the second swing part (65), the resilient member (63) is a spring, one end of which is connected to the first catch (614) and the other end of which is connected to the second catch (654).

5. The ladder with safety lock assembly according to claim 2, characterized in that an arc shaped lead-in slope (616) is provided below said first protrusion (615), and a second arc shaped lead-in slope (655) is provided above said hook (651), said arc shaped lead-in slope (616) being engageable with said second arc shaped lead-in slope (655).

6. A ladder with a safety lock assembly according to claim 1, further comprising a handle sleeve (5), said handle sleeve (5) being provided at an end of the handle (611).

7. A ladder with a safety lock assembly according to claim 1, characterised in that a first cylinder (642) and a second cylinder (644) are provided on the mounting base (64), a first cylinder hole (613) is provided on the first pendulum part (61), the first cylinder hole (613) being rotatably provided on the first cylinder (642); the second swinging part (65) is provided with a second cylindrical hole (652), and the second cylindrical hole (652) is rotatably arranged on a second cylinder (644).

8. A ladder with a safety lock assembly according to claim 7, characterised in that a first mounting post (643) is further provided on the first cylinder (642), a second mounting post (645) is further provided on the second cylinder (644), a first mounting hole (622) and a second mounting hole (623) are provided on the fixing plate (62), respectively, the first mounting hole (622) being provided on the first mounting post (643) and abutting against the first cylinder (642), the second mounting hole (623) being provided on the second mounting post (645) and abutting against the second cylinder (644).

9. The herringbone ladder with the safety lock assembly according to claim 1, further comprising more than one pedal (4), wherein the lower pedals (4) are respectively and rotatably installed on the two front ladder bars (1), and the lower pedals (4) are positioned below the upper pedals (2).

10. The herringbone ladder with the safety lock assembly according to claim 1, further comprising two connecting rods (3), wherein the tops of the connecting rods (3) are respectively rotatably connected with two sides of the upper pedal (2), the upper pedal (2) and the lower pedal (4) are rotatably connected through the connecting rods (3), a guide groove (31) is formed in each connecting rod (3), and the positioning rod (7) penetrates through each guide groove (31).

Technical Field

The invention relates to a herringbone ladder with a safety lock assembly.

Background

The existing herringbone ladder comprises a front ladder frame, a rear ladder frame, an upper pedal, two swing rods and a supporting rod, wherein the front ladder frame comprises two front ladder rods, and the rear ladder frame comprises two rear ladder rods; the two rear ladder bars are respectively and rotatably arranged on the corresponding front ladder bars, one ends of the two swing rods are respectively and rotatably arranged on the corresponding rear ladder bars, the other ends of the two swing rods are respectively and rotatably arranged on two sides of the upper pedal, two sides of one end of the upper pedal are respectively and rotatably arranged on the two front ladder bars, the bearing rods are arranged on the rear ladder bars, and when the ladder is completely opened, the upper pedal is supported on the bearing rods so as to stop swinging downwards; when the ladder is used, the upper pedal can also swing upwards, the ladder cannot be positioned, and when the ladder is used, the upper pedal still shakes, so that the ladder is unsafe to use and low in safety.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide the herringbone ladder with the safety lock assembly.

In order to achieve the purpose, the herringbone ladder with the safety lock assembly comprises a front ladder frame, a rear ladder frame, an upper pedal and a positioning rod, wherein the front ladder frame comprises two front ladder rods, and the rear ladder frame comprises two rear ladder rods; the two rear ladder bars are respectively and rotatably arranged on the corresponding front ladder bars, the upper pedal is rotatably arranged on the two front ladder bars, and the positioning rod is arranged on the two rear ladder bars and is positioned below the upper pedal; characterized by also comprising a safety lock assembly;

the safety lock assembly comprises a first swing part, a fixing plate, an elastic assembly, a second swing part and a mounting seat; the top of the mounting seat is mounted on the upper pedal, the first swing part is rotatably mounted on the mounting seat, one side of the first swing part is provided with a handle, the handle is positioned on one side of the upper pedal, the second swing part is rotatably mounted on the mounting seat and positioned on the other side of the first swing part, one side of the second swing part is provided with a hook, the other side of the first swing part is matched with one side of the second swing part, the first swing part and the second swing part are connected through an elastic component, the first swing part swings to drive the second swing part to swing and then position, and the second swing part swings to lock the hook on the positioning rod to fix the upper pedal; the fixed plate is arranged on the mounting seat and positioned outside the first swing part and the second swing part to position the first swing part and the second swing part in the front-back direction.

In this technical scheme, be equipped with first arch at the opposite side of first goods of furniture for display rather than for use one side of second goods of furniture for display rather than for use is equipped with second arch, first recess and second recess respectively, the second arch is located the top of couple, first recess is located between the second arch and the couple, the second recess is located the bellied top of second, first arch can support respectively and lean on in first recess and second recess, and the swing of first arch drive second goods of furniture for display rather than for use swing.

In the technical scheme, a first through hole is formed in the bottom of the mounting seat, a second through hole is formed in the bottom of the fixing plate, and the positioning rod can penetrate through the first through hole and the second through hole and is locked on the hook.

In this technical scheme the top of first goods of furniture for display rather than for use is equipped with first hook and buckle the top of second goods of furniture for display rather than for use is equipped with the second hook and buckle, elastic component is the spring, the one end and the first hook and buckle of spring are connected, the other end and the second hook and buckle of spring are connected.

In this technical scheme, first bellied below is equipped with the arc and leads the inclined plane the top of couple is equipped with the second arc and leads the inclined plane, the inclined plane is led to the arc can lead the inclined plane cooperation with the second arc.

In the technical scheme, the novel electric bicycle further comprises a handle sleeve, and the end part of the handle is sleeved with the handle sleeve.

In the technical scheme, a first cylinder and a second cylinder are arranged on the mounting seat, a first cylinder hole is formed in the first swing part, and the first cylinder hole is rotatably arranged on the first cylinder; and a second cylindrical hole is formed in the second swing part and is rotatably arranged on the second cylinder.

In the technical scheme, a first mounting column is further arranged on the first cylinder, a second mounting column is further arranged on the second cylinder, a first mounting hole and a second mounting hole are respectively formed in the fixing plate, the first mounting hole is formed in the first mounting column and abutted against the first cylinder, and the second mounting hole is formed in the second mounting column and abutted against the second cylinder.

In the technical scheme, the multifunctional ladder further comprises more than one pedal, the lower pedals are respectively and rotatably arranged on the two front ladder bars, and the lower pedals are positioned below the upper pedals.

In this technical scheme, still include two connecting rods, the top of connecting rod rotates with last footboard both sides respectively and is connected, go up footboard and lower footboard and rotate through the connecting rod and connect be equipped with the guide way on the connecting rod, the locating lever passes in the guide way.

Compared with the prior art, the invention has the advantages that: after the herringbone ladder is opened, the herringbone ladder hook can be quickly and fixedly positioned, and the positioned herringbone ladder is stable, safe and reliable.

Drawings

Fig. 1 is a perspective view of the present invention.

FIG. 2 is an enlarged view of portion A of FIG. 1;

FIG. 3 is a schematic view of the safety lock assembly of the present invention in a latched condition;

FIG. 4 is an exploded view of FIG. 3;

FIG. 5 is a schematic view of the fixing plate of FIG. 3 removed;

FIG. 6 is a perspective view of the present invention in a state where the latch is released;

FIG. 7 is an enlarged view of portion B of FIG. 6;

FIG. 8 is a schematic view of the safety lock assembly of the present invention in an unlocked state;

FIG. 9 is a schematic view of the fixing plate of FIG. 8 with the fixing plate removed;

fig. 10 is a perspective view of a second embodiment of the present invention.

Detailed Description

The following further describes embodiments of the present invention with reference to the drawings. It should be noted that the description of the embodiments is provided to help understanding of the present invention, but the present invention is not limited thereto. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

In the description of the present invention, the terms "left", "right", "top", "upper" and "lower" etc. indicate orientations or positional relationships based on those shown in the drawings, and are for convenience of describing the present invention only without requiring that the present invention must be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention.

In the present invention, unless otherwise explicitly specified or limited, the terms "disposed," "connected," and "mounted" are to be construed broadly, e.g., as meaning fixedly connected, detachably disposed, or integrally formed; they may be mechanically coupled, directly coupled, or indirectly coupled through intervening media, such that there is communication between the two elements or there is an interaction between the two elements. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

Example one

As shown in fig. 1 to 9, a herringbone ladder with a safety lock assembly includes a front ladder frame, a rear ladder frame, an upper pedal 2, a positioning rod 7 and a safety lock assembly 6, wherein the front ladder frame includes two front ladder bars 1, and the rear ladder frame includes two rear ladder bars 8; the two rear ladder bars 8 are respectively and rotatably arranged on the corresponding front ladder bars 1, the upper pedal 2 is rotatably arranged on the two front ladder bars 1, and the positioning rod 7 is arranged on the two rear ladder bars 8 and is positioned below the upper pedal 2;

the safety lock assembly 6 comprises a first swing part 61, a fixing plate 62, an elastic assembly 63, a second swing part 65 and a mounting seat 64; the top of the mounting seat 64 is mounted on the upper pedal 2, the first swing part 61 is rotatably mounted on the mounting seat 64, a handle 611 is arranged on one side of the first swing part 61, the handle 611 is positioned on one side of the upper pedal 2, the second swing part 65 is rotatably mounted on the mounting seat 64 and positioned on the other side of the first swing part 61, a hook 651 is arranged on one side of the second swing part 65, the other side of the first swing part 61 is matched with one side of the second swing part 65, the first swing part 61 and the second swing part 65 are connected through an elastic component 63, the first swing part 61 swings to drive the second swing part 65 to swing and then to be positioned, and the second swing part 65 swings to lock the hook 651 on the positioning rod 7 to fix the upper pedal 2; the fixing plate 62 is mounted on the mounting base 64 and located outside the first swing portion 61 and the second swing portion 65 to position the first swing portion 61 and the second swing portion 65 in a front-back direction.

When the herringbone ladder is used, the herringbone ladder is unfolded from a folded state, when the positioning rod 7 passes through the hook 651, the second swing part swings clockwise to drive the first swing part to swing clockwise and then be positioned, the hook 651 after the second swing part 65 is positioned is locked on the positioning rod 7 to fix the upper pedal 2 (as shown in figures 1, 2, 3 and 5); the herringbone ladder realizes automatic locking, is convenient and quick, and is safe and reliable;

during unlocking, the handle 611 is pressed downwards to drive the first swing part 61 to swing anticlockwise, the first swing part 61 swings anticlockwise to drive the second swing part 65 to swing anticlockwise, the hook 651 is separated from the positioning rod 7, the herringbone ladder is folded, and the herringbone ladder is stored. The lock catch is conveniently released, and the device is convenient, rapid, safe and reliable.

The safety lock assembly 6 can be applied to various ladders and has a wide application range.

In this embodiment, a first protrusion 615 is disposed on the other side of the first swing portion 61, a second protrusion 653, a first groove 656 and a second groove 657 are disposed on one side of the second swing portion 65, the second protrusion 653 is disposed above the hook 651, the first groove 656 is disposed between the second protrusion 653 and the hook 651, the second groove 657 is disposed above the second protrusion 653, the first protrusion 615 can abut against the first groove 656 and the second groove 657 respectively to position the second swing portion 65, and the first protrusion 615 swings to drive the second swing portion 65 to swing.

When the safety lock assembly 6 is in a locked state, the first protrusion 615 and the first groove 656 abut against each other, when the safety lock assembly 6 is to be unlocked, the handle 611 is pressed downwards, the first swing part 61 swings anticlockwise, the first protrusion 615 swings anticlockwise, under the pushing of the elastic assembly 63 and the first protrusion 615 swing anticlockwise, the second swing part 65 swings anticlockwise, after the first protrusion 615 and the second groove 657 abut against each other, the second swing part 65 stops swinging, and the safety lock assembly 6 is in an unlocked state.

In this embodiment, the bottom of the mounting seat 64 is provided with a first through hole 641, the bottom of the fixing plate 62 is provided with a second through hole 621, and the positioning rod 7 can pass through the first through hole 641 and the second through hole 621 and be locked on the hook 651. When the double ladder is completely unfolded, the positioning rod 7 passes through the first through hole 641 and the second through hole 621.

In this embodiment, a first hook 614 is disposed on the top of the first swing member 61, a second hook 654 is disposed on the top of the second swing member 65, and the elastic member 63 is a spring, one end of which is connected to the first hook 614, and the other end of which is connected to the second hook 654.

In this embodiment, an arc-shaped guiding slope 616 is disposed below the first protrusion 615, and a second arc-shaped guiding slope 655 is disposed above the hook 651, wherein the arc-shaped guiding slope 616 is capable of cooperating with the second arc-shaped guiding slope 655. The arc-shaped guiding inclined surface 616 and the second arc-shaped guiding inclined surface 655 are matched with each other, so that the first protrusion 615 is better abutted against the first groove 656, and the hook 651 is better locked on the positioning rod 7 to fix the upper pedal.

In this embodiment, a handle cover 5 is further included, and the handle cover 5 is provided at the end of the handle 611.

In this embodiment, the mounting base 64 is provided with a first cylinder 642 and a second cylinder 644, the first swing element 61 is provided with a first cylinder hole 613, and the first cylinder hole 613 is rotatably provided on the first cylinder 642; a second cylindrical hole 652 is formed in the second rocker portion 65, and the second cylindrical hole 652 is rotatably formed in the second cylinder 644.

In this embodiment, the first cylinder 642 is further provided with a first mounting post 643, the second cylinder 644 is further provided with a second mounting post 645, the fixing plate 62 is provided with a first mounting hole 622 and a second mounting hole 623 respectively, the first mounting hole 622 is provided on the first mounting post 643 and abuts against the first cylinder 642, and the second mounting hole 623 is provided on the second mounting post 645 and abuts against the second cylinder 644.

In this embodiment, the ladder further comprises more than one pedal 4, the lower pedals 4 are respectively rotatably mounted on the two front ladder bars 1, and the lower pedals 4 are positioned below the upper pedals 2.

In this embodiment, still include two connecting rods 3, the top of connecting rod 3 rotates with last footboard 2 both sides respectively and is connected, go up footboard 2 and lower footboard 4 and rotate through connecting rod 3 and connect be equipped with guide way 31 on the connecting rod 3, locating lever 7 passes in the guide way 31.

Example two

As shown in fig. 1 to 10, a herringbone ladder with a safety lock assembly includes a front ladder frame, a rear ladder frame, an upper pedal 2, a positioning rod 7 and a safety lock assembly 6, wherein the front ladder frame includes two front ladder bars 1, and the rear ladder frame includes two rear ladder bars 8; the two rear ladder bars 8 are respectively and rotatably arranged on the corresponding front ladder bars 1, the upper pedal 2 is rotatably arranged on the two front ladder bars 1, and the positioning rod 7 is arranged on the two rear ladder bars 8 and is positioned below the upper pedal 2;

the safety lock assembly 6 comprises a first swing part 61, a fixing plate 62, an elastic assembly 63, a second swing part 65 and a mounting seat 64; the top of the mounting seat 64 is mounted on the upper pedal 2, the first swing part 61 is rotatably mounted on the mounting seat 64, a handle 611 is arranged on one side of the first swing part 61, the handle 611 is positioned on one side of the upper pedal 2, the second swing part 65 is rotatably mounted on the mounting seat 64 and positioned on the other side of the first swing part 61, a hook 651 is arranged on one side of the second swing part 65, the other side of the first swing part 61 is matched with one side of the second swing part 65, the first swing part 61 and the second swing part 65 are connected through an elastic component 63, the first swing part 61 swings to drive the second swing part 65 to swing and then to be positioned, and the second swing part 65 swings to lock the hook 651 on the positioning rod 7 to fix the upper pedal 2; the fixing plate 62 is mounted on the mounting base 64 and located outside the first swing portion 61 and the second swing portion 65 to position the first swing portion 61 and the second swing portion 65 in a front-back direction.

When the herringbone ladder is used, the herringbone ladder is unfolded from a folded state, when the positioning rod 7 passes through the hook 651, the second swing part swings clockwise to drive the first swing part to swing clockwise and then be positioned, the hook 651 after the second swing part 65 is positioned is locked on the positioning rod 7 to fix the upper pedal 2 (as shown in figures 1, 2, 3 and 5); the herringbone ladder realizes automatic locking, is convenient and quick, and is safe and reliable;

during unlocking, the handle 611 is pressed downwards to drive the first swing part 61 to swing anticlockwise, the first swing part 61 swings anticlockwise to drive the second swing part 65 to swing anticlockwise, the hook 651 is separated from the positioning rod 7, the herringbone ladder is folded, and the herringbone ladder is stored. The lock catch is conveniently released, and the device is convenient, rapid, safe and reliable.

The safety lock assembly 6 can be applied to various ladders and has a wide application range.

In this embodiment, a first protrusion 615 is disposed on the other side of the first swing portion 61, a second protrusion 653, a first groove 656 and a second groove 657 are disposed on one side of the second swing portion 65, the second protrusion 653 is disposed above the hook 651, the first groove 656 is disposed between the second protrusion 653 and the hook 651, the second groove 657 is disposed above the second protrusion 653, the first protrusion 615 can abut against the first groove 656 and the second groove 657 respectively to position the second swing portion 65, and the first protrusion 615 swings to drive the second swing portion 65 to swing.

When the safety lock assembly 6 is in a locked state, the first protrusion 615 and the first groove 656 abut against each other, when the safety lock assembly 6 is to be unlocked, the handle 611 is pressed downwards, the first swing part 61 swings anticlockwise, the first protrusion 615 swings anticlockwise, under the pushing of the elastic assembly 63 and the first protrusion 615 swing anticlockwise, the second swing part 65 swings anticlockwise, after the first protrusion 615 and the second groove 657 abut against each other, the second swing part 65 stops swinging, and the safety lock assembly 6 is in an unlocked state.

In this embodiment, the bottom of the mounting seat 64 is provided with a first through hole 641, the bottom of the fixing plate 62 is provided with a second through hole 621, and the positioning rod 7 can pass through the first through hole 641 and the second through hole 621 and be locked on the hook 651. When the double ladder is completely unfolded, the positioning rod 7 passes through the first through hole 641 and the second through hole 621.

In this embodiment, a first hook 614 is disposed on the top of the first swing member 61, a second hook 654 is disposed on the top of the second swing member 65, and the elastic member 63 is a spring, one end of which is connected to the first hook 614, and the other end of which is connected to the second hook 654.

In this embodiment, an arc-shaped guiding slope 616 is disposed below the first protrusion 615, and a second arc-shaped guiding slope 655 is disposed above the hook 651, wherein the arc-shaped guiding slope 616 is capable of cooperating with the second arc-shaped guiding slope 655. The arc-shaped guiding inclined surface 616 and the second arc-shaped guiding inclined surface 655 are matched with each other, so that the first protrusion 615 is better abutted against the first groove 656, and the hook 651 is better locked on the positioning rod 7 to fix the upper pedal.

In this embodiment, a handle cover 5 is further included, and the handle cover 5 is provided at the end of the handle 611.

In this embodiment, the mounting base 64 is provided with a first cylinder 642 and a second cylinder 644, the first swing element 61 is provided with a first cylinder hole 613, and the first cylinder hole 613 is rotatably provided on the first cylinder 642; a second cylindrical hole 652 is formed in the second rocker portion 65, and the second cylindrical hole 652 is rotatably formed in the second cylinder 644.

In this embodiment, the first cylinder 642 is further provided with a first mounting post 643, the second cylinder 644 is further provided with a second mounting post 645, the fixing plate 62 is provided with a first mounting hole 622 and a second mounting hole 623 respectively, the first mounting hole 622 is provided on the first mounting post 643 and abuts against the first cylinder 642, and the second mounting hole 623 is provided on the second mounting post 645 and abuts against the second cylinder 644.

In this embodiment, the ladder further comprises more than one pedal 4, the lower pedals 4 are respectively rotatably mounted on the two front ladder bars 1, and the lower pedals 4 are positioned below the upper pedals 2.

The embodiments of the present invention are described in detail above with reference to the drawings, but the present invention is not limited to the described embodiments. It will be apparent to those skilled in the art that various changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention.