WO2017008222A1

WO2017008222A1 - Roll-over protection system

Info

Publication number: WO2017008222A1
Application number: PCT/CN2015/083859
Authority: WO
Inventors: Gary YU
Original assignee: Volvo Construction Equipment AB
Current assignee: Volvo Construction Equipment AB
Priority date: 2015-07-13
Filing date: 2015-07-13
Publication date: 2017-01-19
Anticipated expiration: 2018-01-13

Abstract

A roll-over protection system (20) for a vehicle (10) includes a lower ROPS (30), an upper ROPS (40) pivotally coupled to the lower ROPS (30), a sunshade (80) pivotally coupled to the upper ROPS (40), and a strap retractor (94) fixed to the sunshade (80). The strap retractor (94) includes a strap box (96) and a strap (98) having a strap end (99). The strap box (96) is fixed to a position on the sunshade (80) and the strap end (99) is fixed to a different position on the sunshade (80) so that at least some part of the strap (98) is exposed above the sunshade (80). The roll-over protection system (20) could be folded and unfolded easily and is steady during transportation.

Description

Roll-over Protection System

TECHNICAL FIELD

The present disclosure relates toroll-over protection systems for vehicles and, more particularly, to foldable roll-over structures for construction vehicles such as wheel loaders, compactors, and graders.

BACKGROUND OF THE INVENTION

For safety reasons, wheel loaders, compactors, graders and otherconstruction vehicles may be equipped with Roll-over Protection Structure (ROPS) systems, i.e. , roll-over protection systems, which provide a structure for supporting the weight of the vehicle in the event of the vehicles rollover to absorb related impact energytherebyprotecting operators from injuries. For this purpose, the heavier the vehicles are, stronger ROPS systems are needed.

Most common ROPS are four-post ROPS or two-post ROPS. Four-post ROPS are usually used in cabs. If a cab is not provided to a vehicle and an operator seat is exposed, two-post ROPS may be used. Each post of the two-post ROPS may be curved and welded tubes.

For some specific reasons, such as decreasingair resistance during transportation or passing through a gateway with a low overhead clearance, the height of the vehicle needs to be adjusted lower and, for this purpose, some roll-over protection systems provide a foldable two-part arrangement, whereinan upper structure is pivotally connected to one end of a lower structure. In this arrangement, the upper structure could be folded down relative to the lower structurefrom a higher operative position to a lower inoperative position. The other end of the lower structure is usually welded on aplatform of the vehicle or bolted on the chassis of the vehicle, and the upper structure and the lower structure are connected by pins or bolts. In some cases, to provide a more comfortable environment to operators, a sunshade is provided together with the ROPS. For two-post ROPS, the sunshade may be bolted onto it.

To reduce the height of the vehicle, the sunshade also needs to be made to be folded down to a lower inoperative position, and the folding and unfolding processes need to beconducted easily with less effort. However, as mentioned above, the heavier the vehicles are, stronger ROPS systems are required to protect operators. Thus, for heavy vehicles, the upper structure and sunshade are too heavy for operators to fold or unfold. In addition, operators should be able to fold and unfold the upper structure and sunshade on the safety platform, without placing himself/herself on tires or some other unsafe places. In addition, the unfolded structure shouldbe steady during transportation.

Accordingly, it would be desirable to provide an improved roll-over protection system with which operators could fold and unfold the upper structure and sunshade easily on safety platform. It would be also desirable to provide an improved roll-over protection system which is steady during transportation.

SUMMARY OF THE INVENTION

According to one aspect of the present disclosure, there provides a roll-over protection system for a vehicle. The roll-over protection system for a vehicle includes a lower ROPS, an upper ROPS pivotally coupled to the lower ROPS, and a sunshade pivotally coupled to the upper ROPS. Also provided is a strap retractor on the sunshade with which an operator canconduct all operations easily on the safety platform, without placing himself/herself on tires or some other unsafe places.

The strap retractor includes a strap box and a strap having a strap end. The strap box is fixed to a position on the sunshade and the strap end is fixed to a different position on the sunshade so that at least some part of the strap is exposed above the sunshade.

The roll-over protection system further includes an unfolding assist assembly coupled to the upper ROPS and to the lower ROPS.

The roll-over protection system further includes an unfolding assist assembly coupled to the sunshade and the upper ROPS.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a vehicle having a roll-over protection system according to an embodiment of the present disclosure in its fully unfolded position；

FIG. 2 is a side view of a vehicle having a roll-over protection system according to an embodiment of the present disclosure of which thesunshade is folded but the upper ROPS is unfolded；

FIG. 3 is a side view of a vehicle having a roll-over protection system according to an embodiment of the present disclosure in its fully folded position；

FIG. 4 is a perspective rear view of a roll-over protection system according to an embodiment of the present disclosure showing the sunshade and the upper ROPS；

FIGS. 5 to 8 are detailed views of a roll-over protection system according to an embodiment of the present disclosure showing part of the upper ROPS and part of the lower ROPS；

FIGS. 9 is a general sectional view of a roll-over protection system according to an embodiment of the present disclosure showing the stopper； and

FIG. 10 is a perspective front view of a roll-over protection system according to an embodiment of the present disclosure showing the sunshade and the upper ROPS.

FIG. 11 is a side view of a vehicle having a roll-over protection system according to another embodiment of the present disclosure in its fully unfolded position；

FIG. 12 is a side view of a vehicle having a roll-over protection system according to another embodiment of the present disclosure of which the sunshade is folded but the upper ROPS is unfolded；

FIG. 13 is a side view of a vehicle having a roll-over protection system according to another embodiment of the present disclosure in its fully folded position；

FIG. 14 is a perspective rear view of a roll-over protection system according to another embodiment of the present disclosure showing the sunshade and the upper ROPS；

FIGS. 15 to 18 are detailed views of a roll-over protection system according to another embodiment of the present disclosure showing part of the upper ROPS and part of the lower ROPS；

FIGS. 19 is a general sectional view of a roll-over protection system according to another embodiment of the present disclosure showing the stopper； and

FIG. 20 is a perspective front view of a roll-over protection system according to another embodiment of the present disclosure showing the sunshade and the upper ROPS.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings. While the present disclosure will be described in conjunction with the following embodiments, it will be understood that they are not intended to limit the present disclosure to these embodiments alone. On the contrary, the present disclosure is intended to cover alternatives, modifications, and equivalents which may be included within the spirit and scope of the present disclosure as defined by the appended claims. Furthermore, in the following detailed description of the present disclosure, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure. However, embodiments of the present disclosure may be practiced without these specific details.

FIGS. 1 to 3show a vehicle 10 in its entirety having a roll-over protection system 20according to an embodiment of the present disclosure, with the roll-over protection system 20 in different states or positions. Vehicle 10 may be a wheel loader, a compactor, a grader or any other type of construction vehicle. As shown in FIGS. 1-3, theroll-over protection system 20 includes a lower ROPS 30 having a pair of posts 34. Posts 34 have an upper end 36 and a lower end 38. Lower ends 38 of posts 34 are fixed to the vehicle 10 by welding on a platform 11 or bolting ontochassis 12. The roll-over protection system 20 further includes an upper ROPS 40 pivotally coupled to lower ROPS 30.

As shown in FIGS. 4 and 10, upper ROPS 40 is a frame having a pair of legs 42 connected by a cross bar 44. As shown in FIGS. 5 to 8, brackets 60 are mounted (e.g. welded or bolted) on legs 42 of upper ROPS 40, and hinges 50 are mounted (e.g. welded or bolted) on the upper ends 36 of posts 34 of lower ROPS 30. Hinges 50 each have two side members. Each bracket 60 is pivotally connected to each respective hinge 50 such that upper ROPS 40 is rotatable about an axis defined by hinge pin 54 penetrating hinge hole 55disposedin hinge 50 and respective hole disposed in bracket 60. In addition to hinge hole 55, hinges 50 each have

holes

52, 53 for locking. Corresponding to these

holes

52, 53, brackets 60 each have

holes

62, 63 for locking. Holes 53 in hinges 50 and holes 63 in brackets 60furthest from hinge pin 54 (See FIGS. 6 and 8) are adapted to receive locking pins 56 which maintain upper ROPS 40 in an unfolded position with respect to posts 34 (see FIGS. 5 and 7) . On the other hand, Holes 52 in hinges 50 and holes 62 in brackets 60 close to hinge pin 54 (See FIGS. 5 and 7) are adapted to receive locking pins 56 which maintain upper ROPS 40 in a folded position with respect to posts 34 (see FIGS. 6 and 8) .

As shown in FIGS. 7 and 8, one end of hinge pin 54 can be fixed by split pin 58 so that hinge pin 54 can be fixed almost permanently in the hinge hole 55. On the other hand, one end of locking pin 56 can be fixed by a clevis pin 57 so that locking pin 56 can berelatively easily moved between

different holes

52, 53 for locking.

As shown in FIG. 9, a stopper 39 is mounted at the position where bracket 60 contacts post34 when the upper ROPS 40 is in its folded position. Stopper 39 may be mounted to one or both of bracket 60 and post 34. In FIG. 9, stopper 39 is mounted to post 34 by inserting the same through a hole formed in post 34. Stopper 39 may be madeof rubber or any suitable material, if only stopper 39 can be made to keep upper ROPS 40 in its folded position correctly so that locking pin 56 can penetrate hinge 50 and bracket 60 easily. In addition, it is desirable to choose material and/or configuration of stopper 39 so that stopper 39 can protect coating of bracket 60 and post 34 from hard to hard impact.

As shown in FIGS. 5 and 6, roll-over protection system 20 also include an unfolding assist assembly 46 coupled to upper ROPS 40 and to lower ROPS 30. Unfolding assist assembly 46 is connected to a bracket 70 mounted on a leg 42 of upper ROPS 40. Unfolding assist assembly 46 is an energy storing member such as a gas spring. Energy is stored in unfolding assist assembly 46 when upper ROPS 40 is moved to its folded position. The stored energy aids an operator in raising upper ROPS 40 to its unfolded position, thereby reducing the force with which the operator is required to exert when rotating upper ROPS 40 to its unfolded position. In case of gas spring, while upper ROPS 40 is folding down, the gas spring get pressed and supports upper ROPS 40. Thus, in addition to the effect discussed above, an operator can softly and smoothly move upper ROPS from to its unfolded high position toits folded low position.

Roll-over protection system 20 further includes a sunshade 80 pivotally coupled to upper ROPS 40. As shown in FIGS. 4 and 10, sunshade 80 has a sunshade frame 82 supporting the shape of sunshade to be maintained. In order to fold sunshade 80 forward and lock it to a folded position and unfold sunshade 80 in reverse, hinges 90 are mounted (e.g. welded or bolted) on rear part of sunshade 80, and brackets 92 are mounted (e.g. welded or bolted) to the upper ROPS 40, for example, to legs 42. The construction regarding holes in the hinges 90 and brackets 92, and pins used for hinging or locking are similar to the construction described in relation to the pivotal coupling of upper ROPS 40 and lower ROPS 30, and thus, a detailed description regarding the same is omitted.

As shown in FIGS. 4 and 10, there is provided a strap retractor 94 to sunshade 80 and this helps an operator to conduct all operations easily on platform 11, without placing himself/herself on tires or some other unsafe places. Strap retractor 94 includes a strap box 96 and s strap 98 having a strap end 99. Strap box 96 is fixed to a position of sunshade 80, and strap end 99 is fixed to a different position of sunshade 80 so that at least some part of the strap 98 is exposed above the sunshade 80. Some part of the strap may also be exposed below the sunshade.

When an operator wants to fold sunshade 80 and upper ROPS 40, the operator stands on one side of platform 11 and releases locking of sunshade 80 and then the sunshade 80 will be folded automatically by gravity from the unfolded position shown in FIG. 1 into the folded position shown in FIG. 2. During this folding process, the operator can hold the sunshade 80 via handle (not shown) on the sunshade 80to slow down the folding speed. Then, the operatorlocks sunshade 80 relative to upper ROPS 40 using means for locking such as locking pins. Thereafter, the operatorreleasesthe locking of upper ROPS 40 and pushessunshade 80 backward to move into the position shown in FIG. 3 and finally locksthis position using locking pins 56 appropriately.

When an operator wants to unfold upper ROPS 40 and sunshade 80, after releasing locking of upper ROPS 40, the operator pulls the part of strap 98exposed above sunshade 80 upwardly to unfold upper ROPS 40 from the position shown in FIG. 3 into the position shown in FIG. 2. Then, the operator locks upper ROPS 40 relative to lower ROPS 30 using locking pins 56 appropriately. Thereafter, the operator releasesthe locking of sunshade 80 and exerts force on the sunshade 80, for example, by pulling the handle on the sunshade 80, to move into the position shown in FIG. 1 and finally locks this position.

Strap box 96 may be fixed in the front lower part of the sunshade and strap end 99 is fixed in the rear part of the sunshade. This enables strap 98 to cover from the front lower part to the rear upper part of the sunshade 80, and an operator can be benefit from this in view of easiness of folding and unfolding work.

Strap box 96 and strap 98 may be positioned along the longitudinal central line of sunshade 80. However, strap box 96 and strap 98 may also be positioned near one side of the sunshade 80, which enables an operator to conduct the folding and unfolding work at one side of platform without interfering or colliding with sunshade 80.

Strap retractor 94 is chosen because, as strap 98 can always contact sunshade 80 tightly, the related arrangement looks tidy and does not hinderan operator in any way when doing normal workwith the vehicle. However, any other means, such as a simple strap disposed in similar way as the strap retractor, can be used for the purpose of helping an operator to conduct all operations easily on platform 11, without placing himself/herself on tires or any other unsafe places.

FIGS. 11 to 13 show a vehicle 110 in its entirety having a roll-over protection system 120 according to another embodiment of the present disclosure, with the roll-over protection system 120 in different states or positions. Vehicle 110 may be a wheel loader, a compactor, a grader or any other type of construction vehicle. As shown in FIGS. 11-13, the roll-over protection system 120 includes a lower ROPS 130 having a pair of posts 134. Posts 134 have an upper end 136 and a lower end 138. Lower ends 138 of posts 134 are fixed to the vehicle 110 by welding on a platform 111 or bolting onto chassis 112. The roll-over protection system 120 further includes an upper ROPS 140 pivotally coupled to lower ROPS 130.

As shown in FIGS. 14 and 20, upper ROPS 140 is a frame having a pair of legs 142 connected by a cross bar 144. As shown in FIGS. 15 to 18, brackets 160 are mounted (e.g. welded or bolted) on legs 142 of upper ROPS 140, and hinges 150 are mounted (e.g. welded or bolted) on the upper ends 136 of posts 134 of lower ROPS 130. Hinges 150 each have two side members. Each bracket 160 is pivotally connected to each respective hinge 150 such that upper ROPS 140 is rotatable about an axis defined by hinge pin 154 penetrating hinge hole 155 disposed in hinge 150 and respective hole disposed in bracket 160. In addition to hinge hole 155, hinges 150 each have holes 152, 153 for locking. Corresponding to these

holes

152, 153, brackets 160 each have holes 162, 163 for locking (See FIG. 17 for 162) . Holes 153 in hinges 150 and holes 163 in brackets 160 furthest from hinge pin 154 (See FIGS. 16 and 18) are adapted to receive locking pins 156 which maintain upper ROPS 140 in an unfolded position with respect to posts 134 (see FIGS. 15 and 17) . On the other hand, Holes 152 in hinges 150 and holes 162 in brackets 160 close to hinge pin 154 (See FIGS. 15 and 17) are adapted to receive locking pins 156 which maintain upper ROPS 140 in a folded position with respect to posts 134 (see FIGS. 16 and 18) .

As shown in FIGS. 17 and 18, one end of hinge pin 154 can be fixed by split pin 158 so that hinge pin 154 can be fixed almost permanently in the hinge hole 155. On the other hand, one end of locking pin 156 can be fixed by a clevis pin 157 so that locking pin 156 can be relatively easily moved between

different holes

152, 153 for locking.

As shown in FIG. 19, a stopper 139 is mounted at the position where bracket 160 contacts post134 when the upper ROPS 140 is in its folded position. Stopper 139 may be mounted to one or both of bracket 160 and post 134. In FIG. 9, stopper 139 is mounted to post 134 by inserting the same through a hole formed in post 134. Stopper 139 may be made of rubber or any suitable material, if only stopper 139 can be made to keep upper ROPS 140 in its folded position correctly so that locking pin 156 can penetrate hinge 150 and bracket 160 easily. In addition, it is desirable to choose material and/or configuration of stopper 139 so that stopper 139 can protect coating of bracket 160 and post 134 from hard to hard impact.

As shown in FIGS. 15 and 16, roll-over protection system 120 also include an unfolding assist assembly 146 coupled to upper ROPS 140 and to lower ROPS 130. One end of the unfolding assist assembly 146 is connected to a bracket 170 mounted on a leg 142 of upper ROPS 140, but unlike the first embodiment, the other end is connected to a post 134 of lower ROPS 130 instead of connecting to a hinge 150 mounted on the upper end 136 of the post. This configuration permits the use of longer unfolding assist assembly 146, which can be more helpful when the weight of upper ROPS 140 and sunshade 180 is large as more energy will be stored in unfolding assist assembly 146. Unfolding assist assembly 146 is an energy storing member such as a gas spring. Energy is stored in unfolding assist assembly 146 when upper ROPS 140 is moved to its folded position. The stored energy aids an operator in raising upper ROPS 140 to its unfolded position, thereby reducing the force with which the operator is required to exert when rotating upper ROPS 140 to its unfolded position. In case of gas spring, while upper ROPS 140 is folding down, the gas spring get pressed and supports upper ROPS 140. Thus, in addition to the effect discussed above, an operator can softly and smoothly move upper ROPS 140 from its unfolded high position to its folded low position.

Roll-over protection system120 further includes a sunshade 180 pivotally coupled to upper ROPS 140. As shown in FIGS. 14 and 20, sunshade 180 has a sunshade frame 182 supporting the shape of sunshade to be maintained. In order to fold sunshade180 forward and unfold sunshade 180 in reverse, hinges 190 are mounted (e.g. welded or bolted) on rear part of sunshade 180, and brackets 192 are mounted (e.g. welded or bolted) to the upper ROPS 140, for example, to legs 142.

As shown in FIGS. 14 and 20, instead of holes and pins used for locking such as in the first embodiment, a first latch 186 and a second latch 187 which is adapted to be engaged with the first latch 186 is used in the present embodiment. The first latch 186 is mounted (e.g. welded or bolted) on rear part of sunshade 180, and the second latch 187 is mounted (e.g. welded or bolted) to the upper ROPS 140. These

latches

186, 187 can be any type of mechanical fastener used to join and locksunshade 180 to upper ROPS 140 in its unfolded position while allowing for eventual separation of the sunshade 180 and upper ROPS 140. With the use of these

latches

186, 187, an operator can easily lock or unlock sunshade 180 with respect to upper ROPS 140, and sunshade 180 can be very stale in its unfolded state.

As shown in FIG. 20, an unfolding assist assembly 185 coupled to sunshade 180 and to upper ROPS 140 is additionally provided in the present embodiment. Unfolding assist assembly 185 is an energy storing member such as a gas spring. Energy is stored in unfolding assist assembly 185 when sunshade 180 is moved to its folded position. The stored energy aids an operator in raising sunshade 180 to its unfolded position, thereby reducing the force with which the operator is required to exert when rotating sunshade 180 to its unfolded position. In case of gas spring, while sunshade 180 is folding down, the gas spring get pressed and supports sunshade 180. Thus, in addition to the effect discussed above, an operator can softly and smoothly move sunshade 180 from its unfolded position to its folded position.

As shown in FIGS. 14 and 20, in the present embodiment, a strap holder 183 which is to be tied with a strap 184 is provided to sunshade 180. However, strap holders can be mounted to at least one of sunshade 180 and upper ROPS 140. An operator can tie the folded sunshade 180 to upper ROPS 140 using this strap holder 183 and a strap 184 as can be seen in FIG. 14 and this can be helpful to lock the sunshade in its folded position.

As shown in FIGS. 14 and 20, there is provided a strap retractor 194 to sunshade 180 and this helps an operator to conduct all operations easily on platform 111, without placing himself/herself on tires or some other unsafe places. Strap retractor 194 includes a strap box 196 and s strap 198 having a strap end 199. Strap box 196 is fixed to a position of sunshade 180, and strap end 199 is fixed to a different position of sunshade180 so that at least some part of the strap is exposed above the sunshade. Some part of the strap may also be exposed below the sunshade.

When an operator wants to fold sunshade 180 and upper ROPS 140, the operator stands on one side of platform 111 and releases locking of sunshade 180 using

latches

186, 187, and then the sunshade 180 will be folded automatically by gravity from the unfolded position shown in FIG. 11 into the folded position shown in FIG. 12. During this folding process, it is not necessary for the operator to hold or support the sunshade 180 because of the support fromthe unfolding assist assembly 185. Then, the operator locks sunshade 180 relative to upper ROPS 140 using a strap 184 which can tie the folded sunshade 180 to upper ROPS 140. Thereafter, the operator releases the locking of upper ROPS 140 and pushes sunshade 180 backward to move into the position shown in FIG. 13 and finally locks this position using locking pins 156 appropriately.

When an operator wants to unfold upper ROPS 140 and sunshade 180, after releasing locking of upper ROPS 140 relative to lower ROPS 130, the operator pulls the part of strap 198 exposed above sunshade 180 upwardly to unfold upper ROPS 140 from the position shown in FIG. 13 into the position shown in FIG. 12. Then, the operator locks upper ROPS 140 relative to lower ROPS 130 using locking pins 156 appropriately. Thereafter, the operator releases the locking of sunshade 180 and exerts force on sunshade 180, for example, by pulling a handle on the sunshade 180, to move into the position shown in FIG. 11 and finally locks this

position using latches

186, 187.

Strap box 196 may be fixed in the front lower part of the sunshade and strap end 199 is fixed in the rear part of the sunshade. This enables strap 198 to cover from the front lower part to the rear upper part of the sunshade 180, and an operator can be benefit from this in view of easiness of folding and unfolding work.

Strap box 196 and strap 198 may be positioned along the longitudinal central line of sunshade 180. However, strap box 196 and strap 198 may also be positioned near one side of the sunshade180, which enables an operator to conduct the folding and unfolding work at one side of platform without interfering or colliding with sunshade 180.

Strap retractor 194 is chosen because, as strap 198 can always contact sunshade 180 tightly, the related arrangement looks tidy and does not hinder an operator in any way when doing normal work with the vehicle. However, any other means, such as a simple strap disposed in similar way as the strap retractor, can be used for the purpose of helping an operator to conduct all operations easily on platform 111, without placing himself/herself on tires or any other unsafe places.

Although the invention has been described with reference to the preferred embodiments in the attached figures, it is noted that equivalents may be employed and substitutions made herein without departing from the scope of the invention as recited in the claims.

Claims

A roll-over protection system for a vehicle, comprising:

alowerROPS including a pair of posts, each post having an upper end and a lower end, the lower end of each lower post being fixed to the vehicle；

an upper ROPS pivotally coupled to the upper ends of the posts between a folded position and an unfolded position；

a sunshade pivotally coupled to the upper ROPS between a folded position and an unfolded position； and

a strap retractor including a strap box and a strap having a strap end, the strap box being fixed to a position on the sunshade, the strap end being fixed to a different position on the sunshade, whereby at least some part of the strap is exposed above the sunshade.
The roll-over protection system for a vehicle as claimed in claim 1, further comprising an unfolding assist assembly coupled to the upper ROPS and to the lower ROPS, the unfolding assist assembly applying a force between the upper ROPS and the lower ROPS to urge the upper ROPS toward the unfolded position.
The roll-over protection system for a vehicle as claimed in claim 2, wherein the unfolding assist assembly is coupled to at least one of the posts of the lower ROPS.
The roll-over protection system for a vehicle as claimed in claim 2, wherein the upper ROPS is a frame having a pair of legs, lower ends of the legs being pivotally connected to respective upper ends of the posts.
The roll-over protection system for a vehicle as claimed in claim 4, further including a first upper ROPS position retainer comprising:

a first hinge mounted on the upper end of one of the posts and having a plurality of first holes disposed therein；

a first bracket mounted to a respective leg of the upper ROPS and pivotally connected to the first hinge, the first bracket having a plurality of second holes disposed therein, one of the plurality of second holes being aligned with one of the plurality of first holes of the first hinge when the upper ROPS is in the folded and unfolded positions； and

a first locking pin adapted to be engaged with the plurality of first and second holes of the first hinge and the first bracket, respectively, to retain the upper ROPS in fixed positions relative to the pair of posts.
The roll-over protection system for a vehicle as claimed in claim 5, further including a second upper ROPS position retainer comprising:

a second hinge mounted on the upper end of the other one of the posts and having a plurality of first holes disposed therein；

a second bracket mounted to a respective leg of the upper ROPS and pivotally connected to the second hinge, the second bracket having a plurality of second holes disposed therein, one of the plurality of second holes being aligned with one of the plurality of first holes of the second hinge when the upper ROPS is in the folded and unfolded positions； and

a second locking pin adapted to be engaged with the plurality of first and second holes of the first hinge and the first bracket, respectively, to retain the upper ROPS in fixed positions relative to the pair of posts.
The roll-over protection system for a vehicle as claimed in claim 5, wherein one end of the first locking pin is fixed by a clevis pin.
The roll-over protection system for a vehicle as claimed in claim 6, wherein one end of the second locking pin is fixed by a clevis pin.
The roll-over protection system for a vehicle as claimed in claim 5, wherein a stopper is mounted at the position where the first bracket contacts a respective post when the upper ROPS is in its folded position.
The roll-over protection system for a vehicle as claimed in claim 6, wherein a stopper is mounted at the position where the second bracket contacts a respective post when the upper ROPS is in its folded position.
The roll-over protection system for a vehicle as claimed in claim 1, wherein the strap box is fixed in the front lower part of the sunshade and the strap end is fixed in the rear part of the sunshade, wherebythe strap covers from front lower part to rear upper part of the sunshade.
The roll-over protection system for a vehicle as claimed in claim 4, further including a first sunshade position retainer comprising:

a first hinge mounted on rear lower part of the sunshade and having a plurality of first holes disposed therein；

a first bracket mounted to the upper ROPS and pivotally connected to the first hinge, the first bracket having a plurality of second holes disposed therein, one of the plurality of second holes being aligned with one of the plurality of first holes of the first hinge when the sunshade is in the folded and unfolded positions； and

a first locking pin adapted to be engaged with the plurality of first and second holes of the first hinge and the first bracket, respectively, to retain the sunshade in fixed positions relative to the pair of legs.
The roll-over protection system for a vehicle as claimed in claim 13, further including a second sunshade position retainer comprising:

a second hinge mounted on rear lower part of the sunshade and having a plurality of first holes disposed therein；

a second bracket mounted to the upper ROPS and pivotally connected to the second hinge, the second bracket having a plurality of second holes disposed therein, one of the plurality of second holes being aligned with one of the plurality of first holes of the second hinge when the sunshade is in the folded and unfolded positions； and

a second locking pin adapted to be engaged with the plurality of first and second holes of the second hinge and the second bracket, respectively, to retain the sunshade in fixed positions relative to the pair of legs.
The roll-over protection system for a vehicle as claimed in claim 1, further comprising an unfolding assist assembly coupled to the sunshade and to the upper ROPS, the unfolding assist assembly applying a force between the sunshade and the upper ROPS to urge the sunshade toward the unfolded position.
The roll-over protection system for a vehicle as claimed in claim 4, further including a first latch mounted on rear part of the sunshade and a second latch mounted to the upper ROPS and adapted to be engaged with the first latch, whereby the sunshade is locked to the upper ROPS in its unfolded position when the two latches engaged.
The roll-over protection system for a vehicle as claimed in claim 4, further including strap holdersmounted to at least one of the sunshade and the upper ROPS, whereby the sunshade is tied to the upper ROPS in its folded position using a strap.
A vehicle having a roll-over protection system according to any one of claims 1 to 16.