CN109966067B

CN109966067B - Wheel chair

Info

Publication number: CN109966067B
Application number: CN201711467527.5A
Authority: CN
Inventors: 于海亮; 曲道奎; 徐方; 邹风山; 包仁人; 邓德智
Original assignee: Shenyang Siasun Robot and Automation Co Ltd
Current assignee: Shenyang Siasun Robot and Automation Co Ltd
Priority date: 2017-12-28
Filing date: 2017-12-28
Publication date: 2020-06-02
Anticipated expiration: 2037-12-28
Also published as: CN109966067A

Abstract

The invention provides a wheelchair which comprises a base part, a sitting surface part, a back part, a sitting surface lifting part, a thigh supporting part, a shank supporting part, a pedal supporting part, a back supporting part, a big leg and small leg linkage mechanism and a control handle. The large and small leg linkage mechanism is hinged to the sitting surface lifting part, the large and small leg linkage mechanism, the small and large leg support part and the pedal support part are connected to the large and small leg linkage mechanism in a lap joint mode, the large and small leg linkage mechanism is installed on the sitting surface lifting part through a second driving device, and the second driving device drives the large and small leg linkage mechanism to move so as to drive the large and small leg support part, the small leg support part and the pedal support part to be switched between a lying posture position and a wheelchair posture position. The wheelchair can be conveniently switched between the lying posture and the wheelchair posture through the driving action of the back support part and the large and small leg linkage mechanisms; the operation is convenient, and the burden of nursing staff and users is greatly reduced.

Description

Wheel chair

Technical Field

The invention relates to the field of equipment for old people and disabled people, in particular to a wheelchair.

Background

In the present society, old people and disabled people become inevitable problems for families, the serious aging of the population is a big social phenomenon in China, and the semi-automatic wheelchair can greatly reduce the burden of the families and nursing staff.

Most of the prior manual wheelchairs are singly pushed by nursing staff, or some electric wheelchairs are controlled by operators independently; however, these manual and electric wheelchairs can only perform simple activities indoors and outdoors, but a person with mobility disability needs to change from the wheelchair to the bed, which is very troublesome and requires cooperation of one or even several persons.

Disclosure of Invention

The present invention is intended to solve at least one of the above-mentioned problems, and to provide a wheelchair which is easy to operate and can greatly reduce the burden on nursing staff and a user.

In order to achieve the purpose, the invention adopts the following technical scheme:

the present invention provides a wheelchair comprising: the base plate part is used for providing a support platform for the wheelchair, and a seat surface lifting part is arranged on the base plate part; the sitting surface part is installed on the base part through the sitting surface lifting part, and the sitting surface lifting part is used for adjusting the height of the sitting surface part; a rear back portion hinged to the seat face portion; a thigh support part hinged with the seat surface part; the lower leg supporting part is hinged with the thigh supporting part; the pedal supporting part is hinged with the lower leg supporting part; the back supporting part is installed on the sitting surface lifting part through a first driving device, the back part is overlapped on the back supporting part, and the first driving device drives the back supporting part to move so as to drive the back part to move, so that the included angle between the back part and the sitting surface part is adjusted; the thigh and calf linkage mechanism is hinged with the sitting surface lifting part, the thigh supporting part, the calf supporting part and the pedal supporting part are lapped on the thigh and calf linkage mechanism, the thigh and calf linkage mechanism is installed on the sitting surface lifting part through a second driving device, and the second driving device drives the thigh and calf linkage mechanism to act so as to drive the thigh supporting part, the calf supporting part and the pedal supporting part to be switched between a lying posture position and a wheelchair posture position; and the control handle is used for controlling and adjusting the lengths of the first driving device and the second driving device.

In some embodiments, the included angle between the thigh support part and the sitting surface part can be switched between 15 degrees and 25 degrees.

In some embodiments, the big and small leg linkage mechanism is a multi-link mechanism including a linkage mechanism driving rod, a first link, a second link, a third link, a fourth link and a fifth link, one end of the linkage mechanism driving rod is connected to the second driving device, the other end of the linkage mechanism driving rod is hinged to the third link through a second hinge point, one end of the first link is hinged to the seat surface lifting part through a third hinge point, a position of the first link near the other end is hinged to one end of the third link through a fourth hinge point, the other end of the first link is hinged to one end of the fourth link through a fifth hinge point, one end of the second link is hinged to the seat surface lifting part through a sixth hinge point, the other end of the second link is hinged to the third link through a seventh hinge point, the other end of the third link is hinged to one end of the fifth link through an eighth hinge point, the other end of the fourth connecting rod is hinged to the fifth connecting rod through a ninth hinge point, the first connecting rod, the third connecting rod, the fourth connecting rod and the fifth connecting rod form a quadrangle, the second hinge point is located between the fourth hinge point and the eighth hinge point, and the seventh hinge point is located between the fourth hinge point and the second hinge point.

In some embodiments, the fourth link is slidably connected to the thigh support via a roller.

In some embodiments, a foldable push handle is arranged on the back part and comprises two handle adapters, two limit screws, a sliding block, a lock nut, a connecting rod and a handle, and the handle adapters are fixed on the back part; one of the handle adaptor pieces is provided with a sliding groove, two ends of the sliding groove are provided with limit screws, and the sliding block can slide in the sliding groove between the two limit screws; the sliding block is provided with a locking nut which is used for locking the sliding block in the sliding groove; one end of the connecting rod is hinged to the sliding block, the other end of the connecting rod is hinged to the handle, and the other end of the handle is hinged to the other handle adapter.

In some embodiments, the seat surface lifting part is provided with a pin for fixing the seat surface lifting part at a certain height.

In some embodiments, the seat surface lifting part is provided with an armrest, and the distance between the armrest and the seat surface lifting part is adjustable.

In some embodiments, the back support is connected to the back by rollers, and the back support is slidable relative to the back.

In some embodiments, the back portion has a race disposed thereon, and the roller is cooperatively disposed within the race.

In some embodiments, the underside of the chassis portion is provided with four wheels, which are universal wheels.

The invention has the beneficial effects that: the wheelchair can be conveniently switched between the lying posture and the wheelchair posture through the driving action of the back support part and the large and small leg linkage mechanisms; meanwhile, the height of the sitting face can be adjusted when the sitting face is in a wheelchair posture and a lying posture by matching the sitting face lifting part with the sitting face so as to adapt to beds or other equipment with different heights. The operation is convenient, and the burden of nursing staff and users is greatly reduced.

Drawings

FIG. 1 is a schematic view of the overall wheelchair attitude of a wheelchair in accordance with an embodiment of the present invention.

Fig. 2 is a schematic view of the whole structure of the lying position of the wheelchair in one embodiment of the invention.

Figure 3 is a schematic view of the overall drive mechanism of the wheelchair in one embodiment of the present invention.

Fig. 4 is a schematic view of the combination structure of the foldable pushing handle and the back part in the using state of the foldable pushing handle in one embodiment of the invention.

Fig. 5 is a schematic view of a combination structure of a non-use state and a back part of a foldable pushing handle in another embodiment of the invention.

Fig. 6 is a schematic view of a foldable pushing handle according to an embodiment of the present invention.

FIG. 7 is a schematic structural view of a big and small leg linkage mechanism in a wheelchair position according to an embodiment of the present invention.

Fig. 8 is a schematic diagram of the linkage mechanism for the big and small legs in the lying position according to an embodiment of the present invention.

Fig. 9 is a schematic view of the combination structure of the chassis part and the seat lifting part according to an embodiment of the present invention.

Reference numerals:

a chassis section 10; a wheel 101; a seat surface elevating section 20; a sitting face portion 30; a back 40; a foldable push handle 400; a handle adaptor 401; a set screw 402; a slider 403; a lock nut 404; a connecting rod 405; a handle 406; a thigh support portion 50; a lower leg support portion 60; a pedal support portion 70; a back support portion 80; a thigh and calf linkage 90; a link mechanism drive rod 901; a first link 911; a second link 912; a third link 913; a fourth link 914; a fifth link 915; a second hinge point 922; a third hinge point 923; a fourth hinge point 924; a fifth hinge point 925; a sixth hinge point 926; a seventh hinge point 927; an eighth hinge point 928; a ninth hinge point 929; a control handle 100; a battery 102; a first drive device 103; a second drive means 104.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate orientations or positional relationships based on those shown in the drawings, and are used merely for convenience of description and for simplicity of description, and do not indicate or imply that the device or element so referred to must have a particular orientation, be constructed in a particular orientation, and be operated, and thus should not be considered as limiting the present invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.

In the present invention, unless otherwise expressly specified or limited, the terms "mounted," "disposed," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

The wheelchair according to the present invention will be described in detail with reference to fig. 1 to 9.

As shown in fig. 1, 2, 3 and 9, in one embodiment of the present invention, a wheelchair includes a base portion 10, a sitting surface portion 30, a back portion 40, a sitting surface elevating portion 20, a thigh support portion 50, a shank support portion 60, a pedal support portion 70, a back support portion 80, a thigh and thigh linkage 90 and a control handle 100.

The base portion 10 is used to provide a support platform for the wheelchair, and the remaining structural components are mounted on the base portion 10. The chassis 10 may be provided with support legs for contacting the ground or other place, but wheelchairs generally have wheels provided at the lower end of the chassis 10.

Meanwhile, the seat lifting part 20 is arranged on the base plate part 10, so that a lifting or descending driving force is provided for the seat part 30 installed on the base plate part 10, the height of the seat part 30 is adjusted, and the seat part 30 is adapted to different heights, so that the operation of a user is facilitated. When the wheelchair is in the lying posture, the seat surface lifting part 20 is adjusted, and the height adjustment of the lying plane can be adjusted to adapt to the heights of different beds or other equipment; when the wheelchair is in the wheelchair position, the height of the sitting portion 30 can be adjusted to accommodate users of different heights.

The sitting surface part 30 is installed on the sitting surface lifting part 20, the sitting surface lifting part 20 is installed on the base part 10, and the height of the sitting surface part 30 can be adjusted through the sitting surface lifting part 20 to adapt to different sitting surface part 30 height requirements.

The rear back portion 40 is hinged to the seating surface portion 30. When the wheelchair is in the wheelchair posture, the back part 40 and the seat part 30 form a certain included angle with each other, and the included angle can be adjusted; the user can adjust the angle between the back 40 and the seat 30 as desired to improve the comfort of the user when the wheelchair is in a wheelchair position. The angle can be adjusted to 180 degrees, and at the moment, the wheelchair is adjusted to be in a lying posture.

Likewise, the thigh support 50 is hinged to the seat surface 30. So set up, thigh supporting part 50 and the angle of sitting face portion 30 are adjustable, realize raising or reducing of user's thigh, adapt to different users' user demand. The angle of the thigh support part 50 to the seat surface part 30 can be adjusted to 180 °, at which time the wheelchair is adjusted to a lying position.

In order to adjust the angle between the upper and lower legs of the user, the lower leg support portion 60 is hinged to the thigh support portion 50, and the user can adjust the lower leg support portion 60 and the thigh support portion 50 to a comfortable use angle according to the requirement. When the wheelchair is adjusted to the lying position, the angle between the thigh support 50 and the shank support 60 is adjusted to 180 °.

Furthermore, the foot support portion 70 is hinged to the lower leg support portion 60, and the angle between the two is adjustable. The user can adjust the included angle between the pedal support portion 70 and the lower leg support portion 60 according to the requirement, so as to improve the use comfort. When the wheelchair is adjusted to the lying position, the angle between the foot support 70 and the lower leg support 60 is adjusted to 180 °.

In order to adjust the included angle between the back part 40 and the seat part 30, a back support part 80 is arranged on the wheelchair, the back support part 80 is installed on the seat lifting part 20 through a first driving device 103, and the back support part 80 is driven to stretch or adjust the angle through the first driving device 103, so that the adjustment of the included angle between the back part 40 and the seat part 30 is realized. The back portion 40 is overlapped on the back support portion 80, and the first driving device 103 drives the back support portion 80 to move, and further drives the back portion 40 to move, so as to adjust the included angle between the back portion 40 and the seat portion 30.

Big shank and small shank link gear 90, big shank and small shank link gear 90 with seat face lift portion 20 is articulated, thigh supporting part 50, shank supporting part 60 and pedal supporting part 70 overlap joint are in on the big shank and small shank link gear 90, big shank and small shank link gear 90 passes through second drive arrangement 104 and installs on seat face lift portion 20, second drive arrangement 104 drive big shank and small shank link gear 90 moves, and then drives thigh supporting part 50, shank supporting part 60 and pedal supporting part 70 change between the position of lying gesture and wheelchair gesture.

The two sides of the sitting face part 30 are provided with control handles 100 for controlling and adjusting the length of the first driving device 103 and the second driving device 104; so as to realize the included angles between all the mechanisms arranged on the seat surface lifting part 20 to change different postures.

According to the wheelchair, the back support part 80 and the large and small leg linkage mechanisms 90 are driven to conveniently switch the wheelchair between the lying posture and the wheelchair posture; meanwhile, the cooperation of the seat surface lifting part 20 and the seat surface part 30 can realize the height adjustment of the seat surface part 30 in the wheelchair posture and the lying posture so as to adapt to beds or other equipment with different heights. The operation is convenient, and the burden of nursing staff and users is greatly reduced. Meanwhile, during the posture of the wheelchair, included angles between the thighs and the buttocks and between the legs are adjustable, the angle of the user is adjusted according to different requirements, the use comfort level is improved, meanwhile, the user is not prone to falling, and the safety and the comfort level are improved.

The design of the control handle 100 (armrest) can adjust different gears to adjust the height of the sitting face part 30, and meet the sitting posture requirements of different heights. Meanwhile, when the wheelchair is in the lying posture, the height of the lying plane is adjusted by multiple gears, the docking requirements of the wheelchair and beds with different heights or other equipment are met, and a user can easily transfer the wheelchair to the beds with different heights or other equipment.

When the thigh supporting part 50 and the seat surface part 30 are in the wheelchair posture, the included angle can be switched and adjusted between 15 degrees and 25 degrees, so that the requirements of different users are met.

Generally, the wheelchair is powered and electrically driven by the battery 102, the control handle 100 is provided with an adjusting button, and a user can conveniently adjust the included angle between the components through the adjusting button arranged on the control handle 100 (armrest), and meanwhile, the wheelchair can be switched between the lying posture and the wheelchair posture.

As shown in fig. 7 and 8, the lower and upper leg link 90 is a multi-link mechanism, and includes a link mechanism driving lever 901, a first link 911, a second link 912, a third link 913, a fourth link 914 and a fifth link 915, one end of the link mechanism driving lever 901 is connected to the second driving device 104, the other end of the link mechanism driving lever 901 is hinged to the third link 913 through a second hinge point 922, one end of the first link 911 is hinged to the seat surface lifting unit 20 through a third hinge point 923, a position of the first link 911 near the other end is hinged to one end of the third link 913 through a fourth hinge point 924, the other end of the first link 911 is hinged to one end of the fourth link 914 through a fifth hinge point 925, one end of the second link 912 is hinged to the seat surface lifting unit 20 through a sixth hinge point 926, and the other end of the second link 912 is hinged to the third link 913 through a seventh hinge point 927, the other end of the third link 913 is hinged to one end of the fifth link 915 through an eighth hinge point 928, the other end of the fourth link 914 is hinged to the fifth link 915 through a ninth hinge point 929, the first link 911, the third link 913, the fourth link 914 and the fifth link 915 form a quadrilateral, the second hinge point 922 is located between the fourth hinge point 924 and the eighth hinge point 928, and the seventh hinge point 927 is located between the fourth hinge point 924 and the second hinge point 922.

The adjustment and driving of the included angle between the back 40, the seat 30, the thigh support 50, the shank support 60 and the pedal support 70 are realized through the hinging among various connecting rods, the driving is convenient, and the action is sensitive.

Meanwhile, in order to achieve stepless adjustment of the angle of the thigh support part 50, the fourth link 914 and the thigh support part 50 are slidably connected by a roller.

As shown in fig. 5, 6 and 7, a foldable push handle 400 is arranged on the back 40, and comprises two handle 406 adapters 401, two limit screws 402, a slider 403, a lock nut 404, a connecting rod 405 and a handle 406, wherein the handle 406 adapters 401 are fixed on the back 40; a sliding groove is formed in the adaptor 401 of one of the handles 406, two ends of the sliding groove are provided with limit screws 402, and the sliding block 403 can slide in the sliding groove between the two limit screws 402; a locking nut 404 is arranged on the sliding block 403, and the locking nut 404 is used for locking the sliding block 403 in the sliding groove; one end of the connecting rod 405 is hinged to the sliding block 403, the other end of the connecting rod is hinged to the handle 406, and the other end of the handle 406 is hinged to the other handle 406 adapter 401.

The limit screw 402 limits the stroke of the slider 403, improving the safety of adjustment of the foldable push handle 400. Meanwhile, a locking nut 404 is matched on the sliding block 403, and when the foldable push handle 400 is adjusted to a proper angle, the locking nut 404 is screwed, so that the angle fixation of the foldable push handle 400 is realized.

The seat surface elevating unit 20 is provided with a plug pin for fixing the seat surface elevating unit 20 at a predetermined height. When the user adjusts the seat surface lifting part 20 to a proper angle, the position of the seat surface lifting part 20 is fixed by the bolt.

The seat surface lifting part 20 is provided with a handrail, and the control handle 100 is arranged on the handrail for convenient adjustment; and the distance between the armrest and the seating surface elevating part 20 is adjustable.

The back support part 80 is connected with the back part 40 through rollers, and the back support part 80 can slide relative to the back part 40.

The back portion 40 is provided with a raceway in which the rollers are disposed in a fitting manner.

Four wheels 101 are arranged on the lower side of the chassis part 10, and the wheels 101 are universal wheels.

The universal wheels are arranged, so that the wheelchair can be controlled conveniently, and the universal wheels are controlled by one central control brake, so that the four universal wheels can be braked simultaneously, and the operation is convenient.

When in use, the chassis part 10 is formed by connecting universal wheels in series through connecting rods. When the height of the sitting face part 30 needs to be adjusted, the sitting face part 30 and the sitting face lifting part 20 are fixed through a bolt, the sitting face part 30 and the sitting face lifting part 20 are fixed, the height of the sitting face part 30 is located, and the sitting face part is matched with beds of different heights. Meanwhile, the armrests can adjust different heights through the elastic bolts, so that users with different heights can use the armrests.

When a user needs to change the wheelchair posture into the lying posture, the posture conversion button on the control handle 100 is pressed, the first driving device 103 and the second driving device 104 act simultaneously to drive the back support part 80 and the big and small leg linkage mechanisms 90 to act, so that the angles among the components are adjusted, and the wheelchair is changed from the wheelchair posture into the lying posture; similarly, when the user needs to change from the lying position to the wheelchair position, the same is true of the user's operation.

Meanwhile, when the posture of the wheelchair is changed and the height of the wheelchair is adjusted, the wheelchair is moved to a use position, the wheels 101 are controlled to brake, the wheelchair is limited at the position, and after corresponding operation (such as moving a user from the wheelchair to a bed) is carried out, the brake function is unlocked, and the wheelchair is moved away. Similarly, when the user needs to move from the bed to the wheelchair, the similar operation can be carried out, and the process is reverse.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made in the above embodiments by those of ordinary skill in the art without departing from the principle and spirit of the present invention.

Claims

1. A wheelchair, comprising:

the base plate part is used for providing a support platform for the wheelchair, and a seat surface lifting part is arranged on the base plate part;

the sitting surface part is installed on the base part through the sitting surface lifting part, and the sitting surface lifting part is used for adjusting the height of the sitting surface part;

a rear back portion hinged to the seat face portion;

a thigh support part hinged with the seat surface part;

the lower leg supporting part is hinged with the thigh supporting part;

the pedal supporting part is hinged with the lower leg supporting part;

the back supporting part is installed on the sitting surface lifting part through a first driving device, the back part is overlapped on the back supporting part, and the first driving device drives the back supporting part to move so as to drive the back part to move, so that the included angle between the back part and the sitting surface part is adjusted;

the thigh and calf linkage mechanism is hinged with the sitting surface lifting part, the thigh supporting part, the calf supporting part and the pedal supporting part are lapped on the thigh and calf linkage mechanism, the thigh and calf linkage mechanism is installed on the sitting surface lifting part through a second driving device, and the second driving device drives the thigh and calf linkage mechanism to act so as to drive the thigh supporting part, the calf supporting part and the pedal supporting part to be switched between a lying posture position and a wheelchair posture position;

the control handle is used for controlling and adjusting the lengths of the first driving device and the second driving device;

the thigh and calf linkage mechanism is a multi-link mechanism and comprises a linkage mechanism driving rod, a first connecting rod, a second connecting rod, a third connecting rod, a fourth connecting rod and a fifth connecting rod, one end of the linkage mechanism driving rod is connected with a second driving device, the other end of the linkage mechanism driving rod is hinged with the third connecting rod through a second hinge point, one end of the first connecting rod is hinged with the seat surface lifting part through a third hinge point, the position of the first connecting rod, close to the other end, is hinged with one end of the third connecting rod through the fourth hinge point, the end part of the other end of the first connecting rod is hinged with one end of the fourth connecting rod through the fifth hinge point, one end of the second connecting rod is hinged with the seat surface lifting part through a sixth hinge point, the other end of the second connecting rod is hinged with the third connecting rod through a seventh hinge point, and the other end of the third connecting rod is hinged with one end of the fifth connecting, the other end of the fourth connecting rod is hinged to the fifth connecting rod through a ninth hinge point, the first connecting rod, the third connecting rod, the fourth connecting rod and the fifth connecting rod form a quadrangle, the second hinge point is located between the fourth hinge point and the eighth hinge point, and the seventh hinge point is located between the fourth hinge point and the second hinge point.

2. A wheelchair in accordance with claim 1, wherein the angle between the thigh support and the seat part is switchable between 15 ° and 25 °.

3. The wheelchair of claim 1 wherein the fourth link is slidably connected to the thigh support via a roller.

4. The wheelchair of claim 1 wherein a foldable push handle is provided on the back portion, comprising two handle adapters, two limit screws, a slider, a lock nut, a connecting rod and a handle, the handle adapters being fixed to the back portion; one of the handle adaptor pieces is provided with a sliding groove, two ends of the sliding groove are provided with limit screws, and the sliding block can slide in the sliding groove between the two limit screws; the sliding block is provided with a locking nut which is used for locking the sliding block in the sliding groove; one end of the connecting rod is hinged to the sliding block, the other end of the connecting rod is hinged to the handle, and the other end of the handle is hinged to the other handle adapter.

5. The wheelchair of claim 1 wherein the seat surface elevating part is provided with a pin for fixing the seat surface elevating part at a certain height.

6. The wheelchair of claim 1 wherein an armrest is disposed on the seat surface riser, the armrest being adjustably spaced from the seat surface riser.

7. The wheelchair of claim 1 wherein the back support is coupled to the back by rollers, the back support being slidable relative to the back.

8. A wheelchair in accordance with claim 7 wherein the rear back portion is provided with a raceway in which the rollers are cooperatively disposed.

9. A wheelchair in accordance with claim 1, wherein the underside of the chassis portion is provided with four wheels, which are universal wheels.