A labor-saving parking brake mechanism

Abstract

The present invention discloses a labor-saving parking brake mechanism, comprising a fixed guide bracket symmetrically mounted on a vehicle body, wherein the front side of the fixed guide bracket is an arc-shaped slide; the fixed guide bracket is rotatably connected to a mounting shaft, the mounting shaft is fixedly connected to an operating handle for driving the mounting shaft to rotate, and a cable support frame is fixedly connected below the mounting shaft; a cable assembly is supported at the contact point between the cable support frame and the arc-shaped slide, and the cable assembly slides along the arc-shaped slide under the drive of the cable support frame. The parking brake mechanism provided by the present invention enables the cable stroke to complete about four-fifths of the total stroke in the first half angle when the operating handle is pulled up and rotated; and the lever ratio is quickly increased in the second half angle when the operating handle is pulled up and rotated, thereby achieving the effect of reducing the operating force. The present invention has a simple structure and is easy to install; by reasonably designing the cable movement path, the operating force is reduced, and the operating comfort is greatly improved.

Description

Technical Field

[0001] The invention belongs to the technical field of forklifts, and in particular relates to a labor-saving parking brake mechanism. Background Art

[0002] The parking brake mechanism of a forklift consists of an operating handle, a fixed bracket, a cable, a brake switch, etc. Its function is to ensure that the forklift can be parked reliably on flat ground or on a ramp without electricity, and it can also be used for emergency braking. Domestic forklifts generally use shoe brakes for parking brakes. This method requires a cam-type brake operating handle. After parking, the driver moves the brake operating handle and pulls the brake rod through the soft shaft embedded in the operating handle. The movement of the rod is transmitted to the brake shoe through the push rod to achieve the purpose of braking; or in wet braking, the friction disk is also pressed by the above-mentioned mechanical push rod to achieve braking. With the improvement of forklift performance, the compact structure is limited, and the parking brake lever ratio is not large enough to ensure parking on a ramp. The driver needs a lot of force to operate in advance. Summary of the invention

[0003] In order to overcome the deficiencies in the prior art, the purpose of the present invention is to provide a labor-saving parking brake mechanism, which ensures that the cable travel is basically completed within the first half angle of the operating handle by reasonably designing the cable movement path. At the same time, in the second half angle, when a greater operating force is required, the lever ratio of the operating handle is increased to reduce the operator's operating force.

[0004] To achieve the above object, the technical solution adopted by the present invention is:

[0005] A labor-saving parking brake mechanism comprises a fixed guide bracket symmetrically installed on a vehicle body, wherein the front side of the fixed guide bracket is an arc-shaped slide; the fixed guide bracket is rotatably connected to a mounting shaft, and the mounting shaft is fixedly connected to an operating handle for driving the mounting shaft to rotate, and a cable support frame is fixedly connected to the lower part of the mounting shaft; a cable assembly is supported at the contact point between the cable support frame and the arc-shaped slide, and the cable assembly slides along the arc-shaped slide under the drive of the cable support frame.

[0006] In a further solution, the cable assembly includes a cable and a rotating shaft fixedly connected to the cable; the rotating shaft rests on the contact point between the cable support frame and the arc slide. A connecting through hole is opened in the middle of the rotating shaft, and one end of the cable passes through the connecting through hole and is fixedly connected to the rotating shaft through an adjusting nut. The parking brake mechanism applies an external force to the operating handle to rotate the mounting shaft relative to the fixed guide bracket, and the mounting shaft drives the cable support frame to rotate simultaneously. Under the drive of the cable support frame, the rotating shaft slides along the trajectory of the arc slide, thereby driving the cable to move. Thereby, the change of the force arm of the cable is achieved, that is, the change of the lever ratio. The design requirement of the path is that when the operating handle is pulled up and rotated around the mounting shaft for the first half angle, the cable stroke completes about four-fifths of the total stroke; when the operating handle is pulled up and rotated around the mounting shaft for the second half angle, the lever ratio is quickly increased to achieve the effect of reducing the operating force.

[0007] In a further embodiment, a mounting hole for fixedly connecting with the mounting shaft is provided at the lower end of the operating handle. The operating handle is fixedly connected with the mounting shaft through the mounting hole.

[0008] In a further solution, the cable support frame is V-shaped; a connecting hole for fixed connection with the mounting shaft is opened at the upper end of the cable support frame, and the cable support frame is fixedly sleeved on the mounting shaft through the connecting hole.

[0009] Compared with the prior art, the present invention has the following beneficial effects:

[0010] (1) The present invention provides a labor-saving parking brake mechanism, which ensures that the cable travel is basically completed within the first half angle of the operating handle by reasonably designing the cable movement path. At the same time, in the second half angle, when a greater operating force is required, the lever ratio is increased to reduce the operator's operating force.

[0011] (2) The present invention has a simple structure, is easy to install, has a low investment cost, and has good economic benefits.

[0012] (3) Compared with the current parking operation mechanism, the parking brake mechanism has a smaller operating force and greatly improved operating comfort. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a structural schematic diagram of the parking brake mechanism.

[0014] Figure 2 An exploded view of the parking brake mechanism.

[0015] Figure 3 This is a schematic diagram of the parking brake mechanism.

[0016] Figure markings: 1-fixed guide bracket, 101-arc slide, 2-installation shaft, 3-operating handle, 301-installation hole, 4-cable support bracket, 5-cable assembly, 501-cable, 502-rotating shaft, 503-connecting through hole, 504-adjusting nut. DETAILED DESCRIPTION

[0017] The present invention is further described below in conjunction with the accompanying drawings and embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] In the present invention, unless otherwise clearly specified and limited, the terms "installation", "connection", "fixed connection" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances. The orientations or positional relationships indicated by the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside" and the like are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention.

[0019] Example 1

[0020] like Figure 1-2As shown, a labor-saving parking brake mechanism includes a fixed guide bracket 1 symmetrically mounted on a vehicle body, the front side of the fixed guide bracket 1 being an arc-shaped slideway 101; the fixed guide bracket 1 is rotatably connected to a mounting shaft 2; the mounting shaft 2 is fixedly sleeved with an operating handle 3 for driving the mounting shaft 2 to rotate; as an embodiment, a mounting hole 301 is provided at the lower end of the operating handle 3, and the operating handle 3 is fixedly connected to the mounting shaft 2 through the mounting hole 301; of course, technicians in this field can also use welding and other methods to achieve the fixed connection between the operating handle and the mounting shaft. A V-shaped cable support frame 4 is fixedly sleeved below the mounting shaft 2, and a connection hole 401 for fixed connection with the mounting shaft 2 is provided at the upper end of the cable support frame 4, and the cable support frame 4 is fixedly connected to the mounting shaft 2 through the connection hole 401. The cable assembly 5 is placed on the contact point between the cable support frame 4 and the arc slide 101. The cable assembly 5 includes a cable 501 and a rotating shaft 502 fixedly connected to the cable 501. A connecting through hole 503 is opened in the middle of the rotating shaft 502. One end of the cable 501 passes through the connecting through hole 503 and is fixedly connected to the rotating shaft 502 through an adjusting nut 504. The rotating shaft 502 is placed on the contact point between the cable support frame 4 and the arc slide 101. When the operating handle 3 is pulled upward, the cable support frame 4 supports the rotating shaft 502 and provides an upward component force to make the rotating shaft 502 slide along the arc slide 101, thereby changing the displacement of the zipper 501.

[0021] The parking brake mechanism applies external force to the operating handle 3 to rotate the mounting shaft 2 relative to the fixed guide bracket 1, and the mounting shaft 2 drives the cable support bracket 4 to rotate simultaneously. Driven by the cable support bracket 4, the rotating shaft 502 slides along the track of the arc slideway, thereby driving the cable to move. Thus, the force arm of the cable is changed, that is, the lever ratio is changed.

[0022] like Figure 3As shown, assuming that AB represents the operating handle 3 as the active rod, arc EGDC represents the motion trajectory of the zipper assembly 5 along the arc slide 101, B represents the rotation center point of the operating handle 3, i.e., the mounting axis, F represents the zipper fixing point, point G represents the zipper assembly 5, BG represents the effective follower lever length, segment ED represents the motion trajectory of the cable 501 when the operating handle 3 rotates around point B for the first half angle during the upward pulling process, segment DC represents the motion trajectory of the cable 501 when the operating handle 3 rotates around point B for the second half angle during the upward pulling process, wherein the angle between BC and BD is equal to the angle between BD and BE, both of which are α, i.e., when the handle 3 is pulled up, the total Stroke angle 2α; let a represent the total stroke of the zipper, c represent the stroke of the zipper 501 in the first half angle of the rotation of the operating handle 3, and b represent the stroke of the zipper in the second half angle of the rotation of the operating handle 3; β is the angle between FC and FD, that is, the angle of change of the zipper 501 when the operating handle 3 is pulled up to the first α angle; θ is the angle between FD and FE, that is, the angle of change of the zipper 501 when the operating handle 3 is pulled up to the first half angle α; the angle of change of the zipper 501 corresponding to the total stroke angle 2α of the operating handle 3 is β+θ, and k represents the lever ratio in this process; then the rope stroke corresponding to the first half angle and the second half angle of the rotation of the operating handle 3 is as follows:

[0023] The travel of the zipper corresponding to the front half of the operating handle: c = l FD -l FE ,

[0024] The corresponding travel of the zipper when the operating handle is rotated to the rear half angle: b = l FC -l FD ,

[0025] The zipper travel ratio corresponding to the front half angle and the rear half angle of the operating handle:

[0026] The total travel of the zipper: a=b+c,

[0027] Leverage Ratio:

[0028] but:

[0029] The range of lever ratio change during the first half of the rotation of the operating handle:

[0030] The range of lever ratio change during the second half of the rotation of the operating handle:

[0031] During the rotation of the operating handle 3, the length of BG changes from long to short, that is, the lever ratio k changes from small to large. The specific process is: in the first half of the rotation of the operating handle 3, that is, the ED stage, the lever is relatively small, saving the pulling height of the operating handle 3; in the second half of the rotation of the operating handle 3, that is, the DC stage, the lever is relatively large, saving the operating force of the operating handle 3 in this process.

[0032] As a preferred embodiment, the lengths of AB, BE, BD, BC, FC, FD, and FE are 263 mm, 83 mm, 39 mm, 23 mm, 125 mm, 120 mm, and 106 mm, respectively; the values ​​of α, β, and θ are 22.5 degrees, 6 degrees, and 24 degrees, respectively; during the first half of the rotation of the operating handle, the travel of the cable c=l FD -l FE =19 mm, the lever ratio k varies from 3.2 to 6.8; during the second half of the rotation of the operating handle, the cable travel b = l FC -l FD =5 mm, the lever ratio k varies from 6.8 to 11.4.

[0033] In the process of transmitting the braking force, the driver's operating force applied to the operating handle 3 is a process of continuous increase. In the first 80% of the total cable travel, the increase in the tensioning force of the zipper 501 is small due to the elimination of the gap between the brake shoe and the brake drum or the gap between the friction plate and the spacer, which is manifested in the driver's operating force on the operating handle being small, equivalent to the weaker braking effect provided at the beginning, and this stage is set as the first half angle of rotation during the pulling process of the operating handle 3; in the last 20% of the total cable travel, due to the beginning of contact between the brake shoe and the brake drum or between the friction plate and the spacer, the friction force required for consuming the vehicle's kinetic energy increases sharply, the increase in the tensioning force of the zipper 501 is large, and the operating force transmitted to the driver's operating handle is large, that is, a stronger braking effect begins to be provided, and this stage is set as the second half angle of rotation during the pulling process of the operating handle 3 end. The variable lever ratio design is because during the braking process of the forklift, before the brake shoe contacts the brake hub or the wet friction plate contacts, the parking brake mechanism is not yet subjected to the force of the vehicle kinetic energy conversion, and the friction force of the mechanism itself is mainly very small; and when the brake shoe begins to contact the brake hub or the wet friction plate begins to contact, it is necessary to overcome a large positive pressure to ensure sufficient friction to stop the vehicle, and at this time a large force is required to operate the brake mechanism. The present invention provides a labor-saving parking brake mechanism, which ensures that the cable travel is basically completed within the first half angle of the operating handle rotation by reasonably designing the cable movement path, and at the same time, in the second half angle, when a greater operating force is required, the lever ratio is increased to reduce the operator's operating force.

Claims

1. A labor-saving parking brake mechanism, characterized in that: The invention comprises a fixed guide bracket (1) symmetrically mounted on a vehicle body, wherein the front side of the fixed guide bracket (1) is an arc-shaped slideway (101); the fixed guide bracket (1) is rotatably connected to a mounting shaft (2), the mounting shaft (2) is fixedly connected to an operating handle (3) for driving the mounting shaft (1) to rotate, and a cable support bracket (4) is fixedly connected below the mounting shaft (2); a cable assembly (5) is supported at the contact point between the cable support bracket (4) and the arc-shaped slideway (101), and the cable assembly (5) slides along the arc-shaped slideway (101) under the drive of the cable support bracket (4); B represents the rotation center point of the operating handle (3), i.e., the mounting axis; point G represents the zipper assembly (5); and BG represents the effective follower lever length. During the rotation of the operating handle (3), the length of BG changes from long to short, i.e., the lever ratio k changes from small to large.

2. The parking brake mechanism according to claim 1, characterized in that: The cable assembly (5) comprises a cable (501) and a rotating shaft (502) fixedly connected to the cable (501); the rotating shaft (502) rests on the contact point between the cable support frame (4) and the arc-shaped slideway (101).

3. The parking brake mechanism according to claim 2, characterized in that: A connecting through hole (503) is provided in the middle of the rotating shaft (502), and one end of the pulling cable (501) passes through the connecting through hole (503) and is fixedly connected to the rotating shaft (502) via an adjusting nut (504).

4. The parking brake mechanism according to claim 1, characterized in that: The lower end of the operating handle (3) is provided with a mounting hole (301) for fixedly connecting with the mounting shaft (2).

5. The parking brake mechanism according to claim 1, characterized in that: The cable support frame (4) is V-shaped.

6. The parking brake mechanism according to claim 1, characterized in that: The upper end of the cable support frame (4) is provided with a connection hole (401) for fixed connection with the installation shaft (2).

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