Trundle mechanism of ladder and ladder using trundle mechanism

Abstract

The utility model relates to the technical field of ladders, in particular to a caster mechanism of a ladder and a ladder using the caster mechanism, the ladder comprises a ladder assembly composed of two supporting columns and steps, and the caster mechanism is arranged beside the bottom end of the ladder assembly. The trundle mechanism comprises a connecting bracket, a rotary arm, a mounting bracket, a trundle, a connecting shaft, a positioning shaft and an elastic piece; the connecting bracket, the rotary arm, the mounting bracket and the trundles are sequentially arranged on the side of the bottom end of the ladder frame in the linear direction; the connecting bracket is connected with the ladder frame; the rotary arm is hinged to the connecting support through the connecting shaft. A locking mechanism is arranged between the rotary arm and the connecting bracket; the positioning shaft is arranged on the rotary arm in a penetrating manner towards the mounting bracket; a concave-convex structure is arranged on the surface, opposite to the mounting bracket, of the rotary arm; the elastic piece acts between the rotary arm and the mounting bracket; and the caster is rotationally arranged on the mounting bracket through the positioning shaft.

Description

TECHNICAL FIELD

[0001] The utility model relates to ladder technical field, concretely relates to a ladder's trundle mechanism and the ladder of using it. BACKGROUND

[0002] As a common climbing operation tool, ladders are widely used in equipment installation, maintenance, cleaning and other fields. In order to improve the portability and mobile flexibility of platform ladders, many designs introduce trundle mechanisms, so that the operator can easily carry the platform ladder between different work sites, significantly improving work efficiency and reducing physical burden.

[0003] When the platform ladder is not in use, it needs to be folded and stored to reduce the occupation of storage space. The traditional trundle mechanism is often directly fixed and installed at the bottom or side of the platform ladder, and because the trundle itself has a certain volume and protrusion, even after the platform ladder is folded, the trundle will still occupy a large space. Even if the trundle mechanism can rotate relative to the platform ladder body along an axis, when the trundle in the trundle mechanism is large, the large trundle is limited by the platform ladder body, resulting in limited folding degree of the trundle mechanism.

[0004] Therefore, how to solve the above-mentioned problems of the prior art, that is, the trundle mechanism causes the platform ladder to occupy more storage space, has become the research and solution of the utility model. UTILITY MODEL CONTENT

[0005] The utility model aims to provide a ladder's trundle mechanism and the ladder of using it.

[0006] In order to achieve the above-mentioned purpose, the utility model adopts the following technical scheme:

[0007] A trundle mechanism of a ladder, the ladder comprising a ladder frame composed of two struts and steps, the trundle mechanism being arranged beside the bottom end of the ladder frame, the trundle mechanism comprising a connecting bracket, a rotating arm, a mounting bracket, a trundle, a connecting shaft, a positioning shaft and an elastic member;

[0008] The connecting bracket, the rotating arm, the mounting bracket and the trundle are sequentially arranged in a straight line direction beside the bottom end of the ladder frame;

[0009] The connecting bracket is fixedly connected with the ladder frame;

[0010] The rotating arm is hinged to the connecting bracket by the connecting shaft, so that the rotating arm can rotate around the axis of the connecting shaft, so that the rotating arm has a supporting working position and a folding working position; a locking mechanism is arranged between the rotating arm and the connecting bracket to position the rotating arm at the supporting working position or the folding working position;

[0011] The positioning shaft is arranged on the swivel arm and extends towards the mounting support, so that the mounting support can rotate around the positioning shaft and move along the length direction of the positioning shaft; the swivel arm and the mounting support are provided with concave-convex structures on the opposite surfaces thereof; the elastic member acts between the swivel arm and the mounting support, so as to force the opposite surfaces of the swivel arm and the mounting support to approach each other and be locked in the rotating direction by the concave-convex structures; and the opposite surfaces of the swivel arm and the mounting support can be unlocked by overcoming the elastic force of the elastic member under the action of an external force;

[0012] The caster is mounted on the mounting support and rotates around the positioning shaft through the mounting support, so that the caster has a working state and a storage state; in the working state, the axis of the caster is parallel to the axis of the connecting shaft in space; in the storage state, the axis of the caster is perpendicular to the axis of the connecting shaft in space;

[0013] When the swivel arm is in the support working position, it forms a certain angle with the height direction of the ladder frame, at this time the caster can be in the working state to support work; when the swivel arm is in the folding working position, it approaches the side of the ladder frame, at this time the caster can be switched to the storage state to reduce the volume.

[0014] In the above scheme, the working state is switched to the storage state, as follows: the connecting support is mounted on the platform ladder and is stationary relative to the platform ladder, and the caster is small; first, the locking member is unlocked to the swivel arm, so that the swivel arm can rotate relative to the connecting support around the axis of the connecting shaft; then the swivel arm is moved from the support working position to the folding working position, realizing the storage of the swivel arm and the preliminary storage of the caster, reducing the space occupied by the caster mechanism; then the mounting support is moved along the length direction of the positioning shaft, so that the protrusion is separated from the limiting groove; then the mounting support is rotated around the axis of the positioning shaft, realizing the secondary storage of the caster. Through the above setting, the swivel arm is stored once, and the caster is stored twice, which can greatly reduce the space occupied by the caster mechanism; for example, when the caster mechanism is arranged on the platform ladder, the caster mechanism is also stored when the platform ladder is stored, and the size of the combined structure of the caster mechanism and the platform ladder in the thickness direction of the stored platform ladder is small.

[0015] It should be emphasized that for carrying the platform ladder, the orientation of the caster in the working state needs to be the same as that in FIG. 1 and FIG. 2; when the caster is large, if the caster can only rotate around the axis of the connecting shaft, the caster will collide with the platform ladder body after a small amplitude of rotation and cannot continue to rotate; through the setting in the embodiment, for a larger caster, the caster can be first rotated around the axis of the positioning shaft to ensure the folding degree of the caster mechanism.

[0016] Through the setting of the locking piece, the swing arm in the working state or the folded state can be locked, the stable work of the caster is facilitated, and the structures in the caster mechanism after folding are prevented from being scattered.

[0017] Through the setting of the positioning shaft, the moving direction of the mounting bracket is limited, and the activity range of the mounting bracket is limited; when the mounting bracket moves along the length extension direction of the positioning shaft, the positioning shaft moves synchronously with the mounting bracket, and the mounting bracket can be considered as being sleeved outside the positioning shaft.

[0018] Through the setting of the protrusion and the limiting groove, when the protrusion is arranged in the limiting groove, the limiting groove limits the rotation of the protrusion and the mounting bracket around the axis of the positioning shaft, and when the two are separated, the mounting bracket can be rotated around the axis of the positioning shaft. The protrusion and the limiting groove can have various settings (such as shape settings), which are not specifically limited here, and one of the settings can be seen from the figure.

[0019] Through the setting of the elastic piece, the automatic reset of the positioning shaft and the mounting bracket in the length extension direction of the positioning shaft can be realized.

[0020] Further technical solutions, the locking mechanism includes a locking piece, a first locking groove and a second locking groove; one of the connecting bracket and the swing arm is provided with the locking piece, and the other is provided with the first locking groove and the second locking groove corresponding to the locking piece; when the swing arm is in the supporting working position, the locking piece is clamped and embedded with the first locking groove to complete positioning, and when the swing arm is in the folding working position, the locking piece is clamped and embedded with the second locking groove to complete positioning.

[0021] This part supplements the specific locking mode as a reference to achieve quick locking.

[0022] Further technical solutions, the locking piece is a locking shaft, the locking shaft is perpendicular to and connected with the positioning shaft, and the two ends of the locking shaft are arranged in the long hole on the connecting bracket or the swing arm, so that the locking shaft can be displaced in the axis direction of the positioning shaft; the positioning shaft is provided with a protruding part and the mounting bracket is clamped and blocked, so that when the mounting bracket moves away from the swing arm, the positioning shaft can be moved together; thus, when the relative surface of the swing arm and the mounting bracket is separated under the action of external force to overcome the elastic force of the elastic piece, the locking shaft is moved by the positioning shaft, so that the locking shaft and the first locking groove or the second locking groove are also simultaneously unlocked.

[0023] When the locking piece can move along the length extension direction of the long hole, the unlocking can be realized on the basis of avoiding the removal of the locking piece from the long hole, and the convenience is improved by the linkage setting.

[0024] Further, the elastic member is a compression spring, and the compression spring is sleeved on the positioning shaft.

[0025] Further, the positioning shaft is a positioning pin, and a large head of the positioning pin is arranged on the mounting bracket.

[0026] Further, the caster is connected with the mounting bracket through a second bolt.

[0027] Further, the mounting bracket comprises a bracket part and a handle part which are arranged separately, the concave-convex structure is arranged on the handle part, and the caster is arranged on the bracket part.

[0028] The handle part is convenient for people to hold, and provides convenience for lifting the caster.

[0029] The application further provides a ladder comprising the caster mechanism in any of the above embodiments.

[0030] The "first", "second", etc. used herein are not intended to particularly indicate the order or sequence, nor to limit the application, but are merely used to distinguish the components or operations described by the same technical terms.

[0031] The "connection" or "positioning" used herein can mean that two or more components or devices are directly in physical contact with each other or indirectly in physical contact with each other, or can mean that two or more components or devices are in operation or action with each other.

[0032] The "contain", "include", "have", etc. used herein are open terms, that is, they mean containing but not limited to.

[0033] The words used herein have their usual meanings in the field, in the content of the application and in the special content, unless otherwise specifically noted. Some words used to describe the application will be discussed below or elsewhere in the specification to provide additional guidance to those skilled in the art on the description of the application.

[0034] The "front", "back", "up", "down", "left", "right", etc. used herein are directional words, which are only used to illustrate the positional relationship between the structures in the application, and are not used to limit the protection scheme and the specific direction in actual implementation.

[0035] The working principle and advantages of the utility model are as follows: hereinafter, the working state switching is taken as the folding state for description, as follows: hereinafter, the connecting support is taken as being installed on the platform ladder and being static relative to the platform ladder, and the smaller trundle is set; firstly, the locking of the locking piece to the rotary arm is released, so that the rotary arm can rotate relative to the connecting support around the axis of the connecting shaft; then the rotary arm is moved from the supporting working position to the folding working position, realizing the folding of the rotary arm and the preliminary folding of the trundle, reducing the space size occupied by the trundle mechanism; then the mounting support is moved along the length extension direction of the positioning shaft, so that the protrusion is separated from the limiting groove; subsequently, the mounting support is rotated around the axis of the positioning shaft, realizing the secondary folding of the trundle. Through the above setting, the rotary arm realizes single folding, and the trundle realizes secondary folding, which can greatly reduce the space size occupied by the trundle mechanism; taking the trundle mechanism arranged on the platform ladder as an example, when the platform ladder is folded, the trundle mechanism is also folded, and the size of the combined structure of the trundle mechanism and the platform ladder in the thickness direction of the folded platform ladder is smaller. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 It is a structure schematic view of the trundle mechanism arranged on the platform ladder and in the working state of the utility model embodiment;

[0037] Figure 2 It is a structure schematic view of the trundle mechanism arranged on the platform ladder and in the working state of the utility model embodiment;

[0038] Figure 3 It is Figure 1 The enlarged view of A in the middle;

[0039] Figure 4 It is Figure 2 The enlarged view of B in the middle;

[0040] Figure 5 It is an exploded view of the trundle mechanism of the utility model embodiment;

[0041] Figure 6 It is a structure schematic view of the trundle mechanism in the working state of the utility model embodiment;

[0042] Figure 7 It is a structure schematic view of the trundle mechanism when the protrusion is separated from the limiting groove of the utility model embodiment;

[0043] Figure 8 It is a structure schematic view of the rotary arm, the handle part and the protrusion of the utility model embodiment.

[0044] In the above drawings: 1, connecting bracket; 11, first locking groove; 12, second locking groove; 2, rotary arm; 21, limiting groove; 22, long hole; 3, connecting shaft; 31, first bolt; 4, locking piece; 5, positioning shaft; 6, elastic piece; 7, mounting bracket; 71, bracket part; 72, handle part; 8, caster; 9, protrusion; 10, first through hole; 13, R-shaped pin; 14, second bolt; 15, strut; 16, step. DETAILED DESCRIPTION

[0045] The utility model will be described further below in combination with the drawings and examples:

[0046] Examples: the following will be described in detail by the drawings and the present case is clearly explained, any person skilled in the art can be changed and modified by the technology taught by the present case after understanding the examples of the present case, which does not deviate from the spirit and scope of the present case.

[0047] The language in this paper is only for describing specific embodiments, and is not intended to limit the present case. The singular form such as "one", "this", "this", "this" and "this", as used herein, also includes the plural form.

[0048] Reference Figures 1-8 A caster mechanism of a ladder, the ladder comprising a ladder frame composed of two struts 15 and steps 16, the caster mechanism is arranged beside the bottom end of the ladder frame, the caster mechanism comprises a connecting bracket 1, a rotary arm 2, a mounting bracket 7, a caster 8, a connecting shaft 3, a positioning shaft 5 and an elastic piece 6.

[0049] The connecting bracket 1, the rotary arm 2, the mounting bracket 7 and the caster 8 are sequentially arranged in a straight line direction beside the bottom end of the ladder frame.

[0050] The connecting bracket 1 is fixedly connected with the ladder frame.

[0051] The rotary arm 2 is hinged to the connecting bracket 1 by the connecting shaft 3, so that the rotary arm 2 can rotate around the axis of the connecting shaft 3, so that the rotary arm 2 has a supporting working position and a folding working position; the locking mechanism is arranged between the rotary arm 2 and the connecting bracket 1 to position the rotary arm 2 in the supporting working position or the folding working position.

[0052] The positioning shaft 5 is arranged on the rotating arm 2 and penetrates the mounting bracket 7, so that the mounting bracket 7 can rotate around the positioning shaft 5 and can move along the length direction of the positioning shaft 5; the opposite surfaces of the rotating arm 2 and the mounting bracket 7 are provided with concave-convex structures; the elastic member 6 acts between the rotating arm 2 and the mounting bracket 7, so as to force the opposite surfaces of the rotating arm 2 and the mounting bracket 7 to be close to each other, and the concave-convex structures are used to lock the rotating arm 2 and the mounting bracket 7 in the rotating direction; and the opposite surfaces of the rotating arm 2 and the mounting bracket 7 can be separated under the action of external force to overcome the elastic force of the elastic member 6.

[0053] The caster 8 is mounted on the mounting bracket 7 and rotates around the positioning shaft 5 through the mounting bracket 7, so that the caster 8 has a working state and a storage state; in the working state, the axis of the caster 8 is parallel to the axis of the connecting shaft 3 in space; in the storage state, the axis of the caster 8 is perpendicular to the axis of the connecting shaft 3 in space.

[0054] When the rotating arm 2 is in the supporting working position, it forms a certain angle with the height direction of the ladder frame, at this time, the caster 8 can be in the working state to support work; when the rotating arm 2 is in the folding working position, it is close to the side of the ladder frame, at this time, the caster 8 can be switched to the storage state to reduce the volume.

[0055] In the working state, the rotating arm 2 is perpendicular to the connecting bracket 1, and the extension direction of the axis of the caster 8 is parallel to the extension direction of the axis of the connecting shaft 3 (see Figure 1 、 Figure 3 ), at this time, the caster mechanism is unfolded, for example, the caster mechanism is mounted on the platform ladder, and the unfolded caster mechanism provides convenience for carrying the platform ladder.

[0056] The concave-convex structure includes the protrusion 9 and the limiting groove 21, which are arranged on the rotating arm 2 and the mounting bracket 7.

[0057] In the storage state, the rotating arm 2 is parallel to the connecting bracket 1, and the extension direction of the axis of the caster 8 is perpendicular to the extension direction of the axis of the connecting shaft 3 and the extension direction of the axis of the positioning shaft 5 (see Figure 2 、 Figure 4 ), at this time, the caster mechanism is stored, and the occupied space area is reduced.

[0058] Herein, the switching from the working state to the folding state is described, and the switching from the folding state to the working state is described as follows: Herein, the connecting bracket 1 is mounted on the platform ladder and is stationary relative to the platform ladder, and the caster 8 is smaller; first, the locking member 4 is unlocked from the rotary arm 2 (for example, the locking member 4 is removed and separated from the rotary arm 2), so that the rotary arm 2 can rotate relative to the connecting bracket 1 about the axis of the connecting shaft 3; then the rotary arm 2 is moved from the supporting working position to the folding working position, so that the rotary arm 2 is folded and the caster 8 is preliminarily folded (see Figure 6 ), and the space occupied by the caster mechanism is reduced; then the mounting bracket 7 is moved along the length extension direction of the positioning shaft 5, so that the protrusion 9 is separated from the limiting groove 21; then the mounting bracket 7 is rotated about the axis of the positioning shaft 5, so that the caster 8 is secondarily folded (see Figure 4 ).

[0059] Through the above arrangement, the rotary arm 2 is folded once, and the caster 8 is folded twice, so that the space occupied by the caster mechanism can be greatly reduced; for example, when the caster mechanism is arranged on the platform ladder, the caster mechanism is also folded when the platform ladder is folded, and the size of the combination of the caster mechanism and the platform ladder in the thickness direction of the folded platform ladder is small.

[0060] It should be emphasized that, for carrying the platform ladder, the orientation of the caster 8 in the working state should be the same as that in Figure 1 , Figure 3 ; when the caster 8 is larger, if the caster 8 can only rotate about the axis of the connecting shaft 3, the caster 8 will collide with the platform ladder body after a small rotation and cannot continue to rotate; through the arrangement in the embodiment, for a larger caster 8, the caster 8 can be first rotated about the axis of the positioning shaft 5 to ensure the folding degree of the caster mechanism.

[0061] Through the arrangement of the locking member 4, the rotary arm 2 in the working state or the folding state can be locked, which facilitates the stable working of the caster 8 and avoids the scattering of the structures in the folded caster mechanism.

[0062] Through the arrangement of the positioning shaft 5, the movement direction of the mounting bracket 7 is limited, and the movement range of the mounting bracket 7 is limited; when the mounting bracket 7 is moved along the length extension direction of the positioning shaft 5, the positioning shaft 5 moves synchronously with the mounting bracket 7, which can be regarded as that the mounting bracket 7 is sleeved outside the positioning shaft 5.

[0063] Through the arrangement of the protrusion 9 and the limiting groove 21, when the protrusion 9 is arranged in the limiting groove 21, the limiting groove 21 limits the rotation of the protrusion 9 and the mounting bracket 7 about the axis of the positioning shaft 5, and when the protrusion 9 and the limiting groove 21 are separated, the mounting bracket 7 can be rotated about the axis of the positioning shaft 5. The protrusion 9 and the limiting groove 21 can have various arrangements (for example, the arrangement of shapes), which are not specifically limited herein, and one of the arrangements can be seen fromFigure 8 .

[0064] By setting the elastic member 6, the positioning shaft 5 and the mounting bracket 7 can be automatically reset in the length extension direction of the positioning shaft 5.

[0065] Referring to Figure 5 , Figure 6 In the embodiment, the connecting bracket 1 and the rotary arm 2 are both provided with first through holes 10 for the connecting shaft 3 to pass through; the connecting shaft 3 (which can also be a connecting member) comprises a first bolt 31, a nut and two washers for connecting the connecting bracket 1 and the rotary arm 2.

[0066] The embodiment shows a specific way of connecting the connecting bracket 1 and the rotary arm 2, in which the two washers are respectively arranged on the two sides of the connecting bracket 1, the first bolt 31 passes through each first through hole 10, and the nut and the two washers are arranged (see Figure 5 ).

[0067] In this way, the first through hole 10 does not need to be a threaded hole, which reduces the degree and difficulty of modification of the connecting bracket 1 and the rotary arm 2.

[0068] Referring to Figure 5 In the embodiment, the locking mechanism comprises a locking member 4, a first locking groove 11 and a second locking groove 12; one of the connecting bracket 1 and the rotary arm 2 is provided with the locking member 4, and the other is provided with the first locking groove 11 and the second locking groove 12 corresponding to the locking member 4; when the rotary arm 2 is in the first position, the locking member 4 is clamped in the first locking groove 11 to complete positioning, and when the rotary arm 2 is in the second position, the locking member 4 is clamped in the second locking groove 12 to complete positioning.

[0069] When the rotary arm 2 is in the supporting working position, part of the locking member 4 is in the first locking groove 11 to lock the rotary arm 2 in the supporting working position.

[0070] When the rotary arm 2 is in the folding working position, part of the locking member 4 is in the second locking groove 12 to lock the rotary arm 2 in the folding working position.

[0071] The first locking groove 11 and the second locking groove 12 correspond to the supporting working position and the folding working position, respectively.

[0072] Here, the rotary arm 2 is taken as an example in the supporting working position, as follows: in one case, when the rotary arm 2 is in the supporting working position, the locking member 4 passes through the first locking groove 11 (see Figure 6 ).

[0073] The embodiment supplements the specific locking mode as a reference to realize quick locking.

[0074] Referring to Figure 6 , Figure 7 In the embodiment, the locking member 4 is a locking shaft which is perpendicular to and connected with the positioning shaft 5, and the two ends of the locking shaft are inserted through the long hole 22 arranged on the connecting support 1 or the rotary arm 2, so that the locking shaft can be displaced in the axial direction of the positioning shaft 5; the positioning shaft 5 is provided with a protrusion which is clamped by the mounting support 7, so that when the mounting support 7 moves away from the rotary arm 2, the positioning shaft 5 can be driven to move together; thus, when the rotary arm 2 and the mounting support 7 are unlocked by overcoming the elastic force of the elastic member 6 under the action of an external force, the positioning shaft 5 drives the locking shaft to move, so that the locking shaft and the first locking groove 11 or the second locking groove 12 are also unlocked at the same time.

[0075] The cross-sectional size of the long hole 22 is greater than that of the locking member 4; the locking member 4 can be moved along the length extension direction of the long hole 22 to separate from the first locking groove 11 or the second locking groove 12.

[0076] When the locking member 4 can be moved along the length extension direction of the long hole 22, the unlocking can be performed on the basis of avoiding the removal of the locking member 4 from the long hole 22, and the convenience is improved by using the linkage arrangement.

[0077] When unlocking, the locking member 4 is directly moved along the length extension direction of the long hole 22, so that the locking member 4 is separated from the first locking groove 11 or the second locking groove 12, which is more convenient and quick.

[0078] Referring to Figure 6 , Figure 7 In the embodiment, the long hole 22 is arranged as a waist-shaped hole; and / or the locking member 4 is arranged as a cylindrical pin.

[0079] The embodiment shows a specific arrangement of the long hole 22, i.e., as a waist-shaped hole (see Figure 6 ), as a reference for understanding.

[0080] The cylindrical pin is a prior art arrangement and is understood by those skilled in the art, and is not expanded here.

[0081] The cylindrical pin is detachably connected with the positioning shaft 5, and can be arranged in the form of a positioning pin (see Figure 6 ).

[0082] Referring to Figure 5In this embodiment, the elastic element 6 is a compression spring; and / or the positioning shaft 5 is a positioning pin, the end of which is provided with a large end that is stuck on the mounting bracket 7; and / or the elastic element 6 and the positioning shaft 5 are connected by an R-type pin 13.

[0083] Optionally, the compression spring is sleeved on the outside of the positioning shaft 5.

[0084] The connection method using R-type pin 13 is an existing setup, understood by those skilled in the art, and will not be described in detail here.

[0085] See Figure 5 , Figure 6 In this embodiment, the caster 8 is connected to the mounting bracket 7 by the second bolt 14.

[0086] Optionally, the axis of caster 8 coincides with the axis of the second bolt 14.

[0087] See Figure 5 , Figure 8 In this embodiment, the mounting bracket 7 includes a detachable bracket portion 71 and a handle portion 72, the protrusion 9 is provided on the handle portion 72, and the caster 8 is mounted on the bracket portion 71.

[0088] The handle 72 is easy to grip and provides convenience for lifting the caster 8.

[0089] Optionally, both the handle portion 72 and the bracket portion 71 are provided with through holes for the positioning shaft 5 to pass through. The combination of the handle portion 72, the bracket portion 71, and the positioning shaft 5 can be found in [reference needed]. Figure 6 .

[0090] Optionally, the protrusion 9 is provided on the surface of the handle portion 72 away from the bracket portion 71; the protrusion 9 includes two pairs of sides; the limiting groove 21 has two protruding ribs, which cooperate to limit the rotation of the two pairs of sides.

[0091] See Figure 1 , Figure 2 A ladder including the caster mechanism of any of the above embodiments.

[0092] The above embodiments are only for illustrating the technical concept and features of this utility model, and are intended to enable those skilled in the art to understand the content of this utility model and implement it accordingly. They should not be construed as limiting the scope of protection of this utility model. All equivalent changes or modifications made in accordance with the spirit and essence of this utility model should be included within the scope of protection of this utility model.

Claims

1. A caster mechanism for a ladder, characterized by: The ladder comprises a ladder frame composed of two columns (15) and steps (16), a caster mechanism is arranged beside the bottom end of the ladder frame, the caster mechanism comprises a connecting support (1), a rotating arm (2), a mounting support (7), a caster (8), a connecting shaft (3), a positioning shaft (5) and an elastic member (6); The connecting support (1), the rotating arm (2), the mounting support (7) and the caster (8) are sequentially arranged in a straight line direction beside the bottom end of the ladder frame; The connecting support (1) is fixedly connected with the ladder frame; The rotating arm (2) is hinged to the connecting support (1) by the connecting shaft (3), so that the rotating arm (2) can rotate around the axis of the connecting shaft (3), so that the rotating arm (2) has a supporting working position and a folding working position; a locking mechanism is arranged between the rotating arm (2) and the connecting support (1) to position the rotating arm (2) in the supporting working position or the folding working position; The positioning shaft (5) is arranged on the rotating arm (2) towards the mounting support (7), so that the mounting support (7) can rotate around the positioning shaft (5) and can move along the length direction of the positioning shaft (5); the opposite surfaces of the rotating arm (2) and the mounting support (7) are provided with concave-convex structures; the elastic member (6) acts between the rotating arm (2) and the mounting support (7), forcing the opposite surfaces to close together, and the concave-convex structures lock the rotating arm (2) and the mounting support (7) in the rotating direction; under the action of external force, the opposite surfaces of the rotating arm (2) and the mounting support (7) can be unlocked by overcoming the elastic force of the elastic member (6); The caster (8) is mounted and supported on the mounting support (7) and rotates around the positioning shaft (5) through the mounting support (7), so that the caster (8) has a working state and a retracted state; in the working state, the axis of the caster (8) is parallel to the axis of the connecting shaft (3) in space; in the retracted state, the axis of the caster (8) is perpendicular to the axis of the connecting shaft (3) in space; When the rotating arm (2) is in the supporting working position, it forms a certain angle with the height direction of the ladder frame, at this time, the caster (8) can be in the working state to support work; when the rotating arm (2) is in the folding working position, it closes to the side of the ladder frame, at this time, the caster (8) can be switched to the retracted state to reduce the volume.

2. The caster mechanism of claim 1, wherein: The locking mechanism comprises a locking piece (4), a first locking slot (11) and a second locking slot (12); one of the connecting support (1) and the rotary arm (2) is provided with the locking piece (4), and the other is provided with the first locking slot (11) and the second locking slot (12) corresponding to the locking piece (4); when the rotary arm (2) is in the supporting working position, the locking piece (4) is clamped with the first locking slot (11) to complete positioning, and when the rotary arm (2) is in the folding working position, the locking piece (4) is clamped with the second locking slot (12) to complete positioning.

3. The caster mechanism of claim 2, wherein: The locking piece (4) is a locking shaft which is perpendicular to and connected with the positioning shaft (5), and the two ends of the locking shaft are penetrated through the long hole (22) provided on the connecting support (1) or the rotary arm (2), so that the locking shaft can be displaced in the axial direction of the positioning shaft (5); the positioning shaft (5) is provided with a convex part which is clamped with the mounting support (7), so that when the mounting support (7) moves away from the rotary arm (2), the positioning shaft (5) can be driven to move; thus, when the rotary arm (2) and the mounting support (7) are unlocked by overcoming the elastic force of the elastic piece (6) under the action of external force, the locking shaft is driven to move by the positioning shaft (5), so that the locking shaft and the first locking slot (11) or the second locking slot (12) are also unlocked.

4. The caster mechanism of any one of claims 1-3, wherein: The elastic piece (6) is a compression spring which is sleeved on the positioning shaft (5).

5. The caster mechanism of any one of claims 1-3, wherein: The positioning shaft (5) is a positioning pin, and the end of the positioning pin is provided with a large head which is clamped on the mounting support (7).

6. The caster mechanism of any one of claims 1-3, wherein: The caster (8) is connected with the mounting support (7) through a second bolt (14).

7. The caster mechanism of any one of claims 1-3, wherein: The mounting support (7) comprises a support part (71) and a handle part (72) which are separately provided, the concave-convex structure is provided on the handle part (72), and the caster (8) is mounted on the support part (71).

8. A ladder characterized by: The caster mechanism comprises the caster mechanism according to any one of claims 1-7. The caster mechanism comprises the caster mechanism according to any one of claims 1-7.

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