UNDERBODY ROPE OPERATED TAIL DOOR LOCKING MECHANISM

FIELD OF THE INVENTION

The present invention relates to a tail door locking mechanism of tipper vehicles. More specifically relates to an underbody rope operated tail door, locking mechanism suitable for all types of tipper vehicles.

BACKGROUND OF THE INVENTION

Presently most of the commercially available tipper vehicles are using mechanically operated underbody tail door locking mechanism as shown in the Fig-1. This locking mechanism is operated by relative motion between a load body and a sub frame. When tipping initiated profile cam (2) slides over hammer assembly (1) which activate longitudinal motion of tie rod (3). The tie rod in turn actuates second profile cam (4) and locking pin (5) which disengage tail door of tipper load body. When the load body tipped approximately for 10 - 12 degree tail door opens by self weight and gravity.

This locking mechanism is failure in all tippers and in all application because actuation of mechanism is not designed properly during un-tipping and closing of tail door. The most commonly observed failures are as follows:

1. Tail door is not closing properly.

2. Hammer assembly and profile cam-1 breakage (bending and welding crack)

3. Tie rod bending.

4. Locking pin damaged.

5. Frequently servicing required.

In the past different types of tail door locking arrangement operated using different mechanism (such as hydraulic, pneumatic and mechanically) were conceptually tried and verified. In the hydraulic operated tail door system, the tail door of the vehicle is hydraulically operated through, power pack to load or unload. The tail door has got two movement and tilt movement to come from vertical to horizontal position and vice versa and lift movement to move upward and downward horizontally to the ground level. On touching the ground, the platform makes the small angle to the ground and the load can be wheeled to the platform and then can be taken up to the vehicle platform level.

However, all these operating mechanisms are found to be unsuitable for the Indian market application and tipper usage. Hence, there is a need to provide a locking mechanism which facilitates to operate the tail door reliably during tipping and untipping of the load body.

OBJECT OF THE INVENTION

In order to solve any one of the above described problems, present invention provides a locking mechanism for the operation of the tail door of tipper vehicles which is positive, reliable and easy to operate.

This locking mechanism is operated using a flexible wire rope/chain. The proposed locking mechanism of the present invention is developed and designed to suit Indian market, usage, different application, customer requirement and serviceability etc.
Further object is to design a tail door locking mechanism suitable for all types of tipper vehicles.

SUMMARY OF THE INVENTION

In accordance with the present invention, a locking mechanism (21) for operating a tail door of tipper vehicles comprising three main sub assemblies as shown in Fig-2. The sub assemblies are

1. Locking pad arrangement (6).

2. Wire Rope/Chain (8).

3. Chassis clamping arrangement (7).

The locking mechanism (21) of present invention comprises at least one locking pad arrangement (6). However it is preferable to have two locking pad arrangements (6) .The locking pad arrangement (6) is fixed to the bottom wall/ floor back-up plate (11) of load body of the tipper vehicle as shown in Fig.3. The locking pad arrangement (6) comprises a locking pad (9), a hinge clip (10), a floor back-up plate, (11) a first revolute joint (12), a second revolute joint (13) and stiffener (14). The main purpose of locking pad arrangement (6) is to hold tail door at its position during running condition of vehicle.

The chassis clamping arrangement (7) comprises a plurality of chassis supporting plate (16), a plurality of eyebolts (17) and an eyebolt support arrangement (18). The chassis supporting plates are bolted to the chassis frame (19) of the vehicle. An eyebolt support arrangement (18) is preferably fixed to chassis support plates (16) in perpendicular direction. The locking pad arrangement (6) and the chassis clamp arrangement (7) are connected through a wire rope/chain (8).

Each one of the eyebolts (17) is connected to the eyebolt support arrangement (18) by nut and bolt. One end of the wire rope/chain (8) is clamped to the eyebolt (17) and other end of the wire rope/ chain is attached to the second revolute joint (13) of the locking pad arrangement(6). The eyebolt (17)-and locking part will be forged one. The eyebolt (17) is having threads by which length/tension of wire rope/chain (8) will be adjusted if wire rope/ chain (8) get slack during running condition of the vehicle.

The tension in the wire rope/ chain (8) decreases / increases during tipping /untipping of a load body (20), which activates the second revolute joint (13). The second revolute joint in turn (13) actuates the locking pad (9) of locking pad arrangement and slides the locking pad (9) to change its position from locking to unlocking and vice versa. This movement of locking pad (9) helps in safe and fast operation of opening and closing of the tail door (22).

Various objects and advantages of this invention will become apparent to those skilled in the art from the following description, when read in light of accompanying drawings.

BRIEF DISCRIPTION OF THE ACCOMPANYING DRAWINGS

The advantages and features of the invention will become more clearly apparent from the following description which refers to the accompanying drawings given as non-restrictive examples only and in which:

Figure 1 shows a tail door locking mechanism of tipper vehicle in accordance with the prior art.

Figure 2 shows a tail door locking mechanism of tipper vehicle in accordance with the present invention.

Figure 3 shows locking pad arrangement of the proposed tail door locking mechanism of Figure 2.

Figure 4 shows a chassis clamping arrangement of the proposed locking mechanism of Figure 2.

Figure 5 shows a tipper vehicle with the load body and the proposed locking mechanism.

Figure 6 shows the tail door of the proposed locked mechanism in open/unlock position.

Figure 7 shows the isometric view of proposed locking mechanism.

Figure 8 shows the front view of proposed locking mechanism.

Figure 9 shows the rear view of proposed locking mechanism.

Figure 10 shows the top view of proposed locking mechanism.

Figure 11 -shows the bottom view of proposed locking mechanism.

Figure 12 shows the side view of tipper vehicle with the proposed locking mechanism.

DETAILED DESCRIPTION OF THE INVENTION

The present invention comprises of a load body (20) having a tail door (22), the tail door (22) located on the discharge side of the load body (20). The tail door (22) is being flexibly connected with and movable relatively to the rest of the load body (20). The load body (20) may be supported on a chassis frame (19), and may be pivotally mounted to the chassis frame (19). Further, a locking mechanism (21) is provided, which facilitates to operate the tail door reliably during tipping and untipping of the load body such that material held within the load body (20) can be tipped from the tail door (22) thereof when the tail door (22) is in open position.

The novel locking mechanism (21) for the safe and reliable operation of a tail door (22) of tipper vehicle is described in the following description. The locking mechanism (21) comprises of a plurality of locking pad arrangements (6), a chassis clamp arrangement (7) and a wire rope/chain(8) connecting the plurality of locking pad arrangement(6) and the chassis clamp arrangement(7) as shown in the Fig 2. This locking mechanism (21) of the present invention is mechanically operated positive locking system using a flexible wire rope/chain (8).

The locking mechanism (21) of present invention comprises at least one locking pad arrangement (6). However it is preferable to have two locking pad arrangements (6) located on both the ends of bottom wall/floor back up plate (11) as shown in Fig-2. The locking pad arrangement (6) comprises a locking pad (9), a hinge clip (10), a floor back-up plate (11), a first revolute joint (12), a second revolute joint (13) and stiffeners (14, 15). The main purpose of locking pad arrangement (6) is to hold the tail door (22) at its position during running condition of vehicle. The locking pad arrangement (6) is fixed to the bottom wall/ floor back-up plate (11) of load body (19). of the tipper vehicle as shown in Fig -3.

Further, the chassis clamping arrangement (7) of the present invention comprises of plurality of chassis supporting plates (16), an eyebolt support arrangement (18) and plurality of eyebolts (17). The chassis supporting plate (16) which connects the frame (19) of the tipper vehicle and eyebolt support arrangement (18) is preferably bolted to the chassis frame (19) of the vehicle. The eyebolt support arrangement (18) is fixed to the chassis supporting plates (16) in

perpendicular direction and pluralities of eyebolts (17) are attached to the eyebolt support arrangement (18) preferably by means of nets and bolts.

An eyebolt (17) is a screw with a loop on one end and threads on the other end. One end of wire rope/chain (8) is clamped to loop end of the eyebolt and other end is attached to the

second revolute joint (13) of the locking pad arrangement (6). These first (12) and second revolute joints (13) provide single or multiple axis rotation functions. The threads of the eyebolt help in adjusting the length and tension of the wire rope/chain (8), if wire rope/chain gets slack during running condition. Stiffeners (14) are provided to avoid rubbing of wire rope/chain to bottom wall/floor back-up plate (11) to avoid wear and tear.

This wire rope/chain rope (8) passes through the bottom wall or floor back up plate (11). Further the strengthening stiffeners (15) are also provided at the floor back up plate (11) as shown in the Fig.4.

In one of the embodiment of the present invention, opening and closing mechanism of the tail door (22) during tipping and untipping of load body (20) is presented. This locking mechanism (21) is actuated by relative motion between the load body (20) and sub frame (23) as shown in the Fig. 12. The locking pad (9) of locking pad arrangement (6) is being movable from deactivated position (unlock) to activated position (lock) and vice versa with the rotation of second revolute joint (13).This second revolute joint (13) in turn activated by tipping/untipping of a load body (20).

When load body (20) tipping starts to discharge the material, wire rope / chain (8) slacks i.e. tension in wire rope/ chain (8) will fall down and the locking pad will fall behind because of self weight and gravity. This causes the tail door (22) to open from its closed position and tail door (22) will open at approximately 12 deg. of tipping angle because of gravity as shown in the Fig.6. The locking pad (9) position is maintained such that, while material discharge sand or gravel or small boulders should not fall on locking pad (9) as shown in Fig, 5.

After discharge of material, the load body (20) is bought to its original position during with the tail door (22) of the Fig.6 also comes to its closed position. Subsequently, due to increase in tension of wire rope/chain (8), the locking pad (9) of locking pad arrangement (6) is pulled to its original position thereby locking the tail door (22).

The Wire rope/chain (8) of preferably 10 mm diameter (less than 10 mm) (6x19 group) will be used to retain load coming on locking assembly during running condition. It may be noted that wire rope/chain (8) of different thickness and material can be used depending upon the requirement.

Further, Fig7-Fig 11 shows the isometric, front, rear, bottom and top views of the proposed locking mechanism (21) for unlocking and locking of the tail door (22) during tipping and untipping of the load body (20).

This proposed locking mechanism (21) of tail door (22) facilitates the safe and reliable operation of unlocking and locking of the tail door (22) during tipping and untipping of the load body (20) and also reduces the tipper/trucks stoppage time while loading and unloading.

We claim:

1. A tipper vehicle with an underbody operated tail door (22) locking mechanism (21), the
tipper vehicle comprising:
a load body (20) pivotally mounted on a chassis frame (19);
a tail door (22) located on a discharge side of the load body, wherein said tail door being flexibly connected with the load body (20);
a plurality of locking pad arrangements (6) fixed on a bottom wall/floor back up plate (11) of the load body (20) comprising a locking pad (9), a hinge clip (10), a first revolute joint (12) and a second revolute joint (13);
a plurality of chassis supporting plates (16) joined together to the chassis frame (19);
an eyebolt support arrangement (18) fixed to each one of the said chassis supporting plates (16) in perpendicular direction;
a means for joining a plurality of eyebolts (17) to the said eyebolt support arrangement (18);
a means for connecting each one of the second revolute joint (13) of the locking pad arrangement (6) to each one of the eyebolt (17) and
wherein said locking pad (6) is being movable to unlock and lock the tail door and vice versa with the rotation of the second revolute joint (13) which in turn actuated by increasing/ decreasing the tension of the connecting means during tipping/untipping of the load body (20).

2. The tipper vehicle according to claim'1', wherein said connecting means is preferably a wire rope or chain (8).

3. The tipper vehicle according to claim'1', wherein said locking mechanism (21) preferably comprises two locking pad arrangements (6) located on both the ends of said bottom wall/floor back up plate (11).

4. The tipper vehicle according to claim'1', wherein said locking pad arrangement (6) is provided with stiffeners (14) to avoid rubbing of rope to floor back up plate.

5. The tipper vehicle according to claim' 1', wherein said wire rope/chain (8) is about 10mm diameter

6. The tipper vehicle according to claim' land 2\ wherein one end of said wire rope/chain (8) is attached to the second revolute joint (13) of the locking pad arrangement (6) in such a way that the wire rope/ chain (8) passes through the bottom wall/floor back up plate (ll)ofloadbody(20).

7. The tipper vehicle according to claim T, wherein said means for joining plurality of eyebolts (17) with the eyebolt support arrangement (18) is by bolted nuts.

8. The tipper vehicle according to claim'1', wherein said eyebolt (17) is provided with threads on one end for adjusting the length/tension of said wire rope/chain if wire rope/chain gets slack during running condition.

9. A method for operating a tail door a tipper vehicle, said method comprising:
actuating the mechanism of a locking device by causing the relative motion between a load body (20) and a vehicle frame;
tipping the load body (20) to discharge the material, this tends to decrease the wire rope/chain tension (8) and moving the locking pad (9) away from the floor back up plate (11) by self weight and gravity and thereby opening the tail door (22).
untipping the load body (20) to retain its original position after discharging the material, this tends to close the tail door (22) by increasing the tension of wire rope/ chain (8) and thereby pulling the locking pad (9) to its original closed position to engage/locking the tail door (22).

10. The method according to claim'9', wherein said tail door (22) opens at an angle of about 12 deg during unloading the material from load body (20).