CN111252719A

CN111252719A - Filling machine

Info

Publication number: CN111252719A
Application number: CN202010103180.1A
Authority: CN
Inventors: 韩天章
Original assignee: Individual
Current assignee: Individual
Priority date: 2020-02-19
Filing date: 2020-02-19
Publication date: 2020-06-09

Abstract

The invention belongs to the technical field of filling, and discloses a filling machine, which comprises a machine body with a storage space, a plurality of working water tanks, a main water tank, a lifting mechanism and a conveying mechanism, wherein the lifting mechanism and the conveying mechanism enable the working water tanks to move up and down; the working water tank is arranged in the storage space of the machine body; the main water tank is connected with the working water tank through a flow divider; the lifting mechanism is arranged at the top of the machine body; conveying mechanism sets up in the outside of organism, conveying mechanism loads and has a plurality of containers of treating the filling, and every working water tank leads to pipe rather than the container intercommunication that corresponds, the water pipe is equipped with first valve. The invention has smaller volume, occupies less space, can fill a plurality of containers at one time, and can effectively improve the production efficiency of the filling production line.

Description

Filling machine

Technical Field

The invention belongs to the technical field of filling, and particularly relates to a filling machine.

Background

Filling machines belong to a sub-group of packaging machines, generally used for filling with containers and not limited to solids and fluids, and in general can be divided into liquid filling machines, paste filling machines, pellet filling machines, etc.

In the existing filling machine, the number of containers filled in a single time is small, so that the filling time required by a production line is long, and the filling machines designed by a plurality of manufacturers have large volumes and wide occupied areas, thereby bringing great inconvenience to the manufacturers.

Disclosure of Invention

In order to solve the problems, the invention discloses a filling machine which has smaller volume and occupies less space, can fill a plurality of containers at one time and can effectively improve the production efficiency of a filling production line. The specific technical scheme of the invention is as follows:

a filling machine comprises a machine body with a storage space, a plurality of working water tanks, a main water tank, a lifting mechanism and a conveying mechanism, wherein the lifting mechanism and the conveying mechanism enable the working water tanks to move up and down; the working water tank is arranged in the storage space of the machine body; the main water tank is connected with the working water tank through a flow divider; the lifting mechanism is arranged at the top of the machine body; conveying mechanism sets up in the outside of organism, conveying mechanism loads and has a plurality of containers of treating the filling, and every working water tank leads to pipe rather than the container intercommunication that corresponds, the water pipe is equipped with first valve.

Preferably, a bearing plate is arranged in the storage space; the working water tank is arranged on the bearing plate; the bearing plate is connected with the transmission end of the conveying mechanism.

Preferably, the conveying mechanism comprises a driving wheel arranged at two ends of the top of the machine body, a driven wheel arranged at the bottom of the storage space of the machine body and a motor; the two driving wheels are connected through a first synchronous shaft; the two driven wheels are connected through a second synchronous shaft; the driving end of the motor is connected with any one driving wheel through a coupler; the driving wheel at any side is connected with the driven wheel arranged at the same side of the machine body through a synchronous belt; one end of the bearing plate is connected with one synchronous belt, and the other end of the bearing plate is connected with the other synchronous belt.

Preferably, one side of any one driving wheel is provided with a first bearing seat; the first synchronous shaft simultaneously penetrates through the two first bearing seats; one side of any driven wheel is provided with a second bearing seat; the second bearing block passes through both second bearing blocks simultaneously.

Preferably, the conveying mechanism comprises a filling platform for loading the container, a conveying main board, a conveying plug board and a platform to be filled; one end of the filling platform is positioned below the water outlet of the water pipe; the conveying main board is positioned at one end of the filling platform and is in sliding connection with the filling platform; the conveying inserting plate is positioned at the other end of the filling platform and is in sliding connection with the filling platform; one end of the platform to be filled is connected with one end of the filling platform far away from the water pipe, and the other end of the platform to be filled is provided with a bottle pushing plate; a gap for the conveying insertion plate to slide in is arranged between the filling platform and the platform to be filled; the conveying main board, the conveying plug board and the bottle pushing board are all provided with automatic push rods for driving the conveying main board, the conveying plug board and the bottle pushing board to move.

Preferably, two sides of the platform to be irrigated are provided with baffles; any baffle is provided with a through hole; the conveying mechanism further comprises an alignment plate; one end of the inserting and aligning plate extends into the platform to be irrigated through the penetrating hole; the inserting and aligning plate is also provided with an automatic push rod for driving the inserting and aligning plate to move.

Preferably, the filling platform is arranged in the middle of the machine body.

Preferably, the top of any one working water tank is provided with a water inlet and is communicated with the main water tank through a flow divider; the top of any one working water tank is also provided with an exhaust port; the bottom of any water tank is provided with a water outlet.

Preferably, the water inlet of the working water tank is provided with a second valve.

Preferably, the bottom of the machine body is provided with a universal wheel with a brake device.

Compared with the prior art, the liquid filling device realizes liquid filling of the containers by utilizing the height difference, and has the function of filling a plurality of containers at one time; through the synergistic effect of the lifting mechanism and the conveying mechanism, the circular filling process is well completed, the filling time is saved, and the filling efficiency is improved; in the invention, no matter the lifting mechanism or the conveying mechanism, the structure is simpler, and the action principle is easy to realize, so that the worker can quickly operate by hands; in the invention, as long as the height of the working water tank exceeds the filling platform, the working water tank can discharge water, and any distance from the height to the upper part can be used for setting an accurate filling line, thereby meeting the requirement of the invention on the filling accuracy.

Drawings

FIG. 1 is a state diagram of an embodiment of the present invention;

FIG. 2 is a schematic diagram of another state of an embodiment of the present invention;

FIG. 3 is a schematic front view of an embodiment of the present invention;

FIG. 4 is a schematic view of the lifting mechanism of the present invention;

FIG. 5 is a schematic view of the initial position of the lift mechanism of the present invention;

FIG. 6 is a schematic view of the water discharge control state of the lifting mechanism according to the present invention;

FIG. 7 is a schematic view of the working tank of the lift mechanism of the present invention in a emptied state;

FIG. 8 is a schematic view of the locking state of the transport mechanism of the present invention;

FIG. 9 is a schematic view showing the feeding state of the conveying mechanism according to the present invention;

FIG. 10 is a schematic view of the return position of the conveying mechanism of the present invention;

FIG. 11 is a schematic view of the feed mechanism of the present invention in a ready state;

FIG. 12 is a schematic view showing a container entering state of the conveying mechanism according to the present invention;

FIG. 13 is a schematic view of the secondary lock of the delivery mechanism of the present invention;

fig. 14 is a schematic view of the secondary feeding of the conveying mechanism of the present invention.

In the figure: 1-body; 2-a working water tank; 3-a main water tank; 4-a flow divider; 5-a container; 6-carrying and installing the plate; 7-driving wheel; 8-a first synchronization shaft; 9-a driven wheel; 10-a second synchronizing shaft; 11-a motor; 12-a synchronous belt; 13-a first bearing seat; 14-a second bearing block; 15-a filling platform; 16-conveying the main board; 17-conveying plug boards; 18-a platform to be irrigated; 19-a bottle pushing plate; 20-a baffle plate; 21-aligning the plates; 22-initial position line; 23-main tank water line; 24-water discharge waterline; 25-a water discharging precision adjusting line; and 26-emptying the clear water line.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. The components of embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.

In the description of the embodiments of the present invention, it should be noted that the indication of the orientation or the positional relationship is based on the orientation or the positional relationship shown in the drawings, or the orientation or the positional relationship which is usually placed when the product of the present invention is used, or the orientation or the positional relationship which is usually understood by those skilled in the art, or the orientation or the positional relationship which is usually placed when the product of the present invention is used, and is only for the convenience of describing the present invention and simplifying the description, but does not indicate or imply that the indicated device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and therefore, cannot be understood as limiting the present invention. Furthermore, the terms "first" and "second" are used merely to distinguish one description from another, and are not to be construed as indicating or implying relative importance.

In the description of the embodiments of the present invention, it should be further noted that the terms "disposed" and "connected" are to be interpreted broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected, unless explicitly stated or limited otherwise; may be directly connected or indirectly connected through an intermediate. For those skilled in the art, the drawings of the embodiments with specific meanings of the terms in the present invention can be understood in specific situations, and the technical solutions in the embodiments of the present invention are clearly and completely described. The components of embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.

The invention is further illustrated with reference to the accompanying drawings and specific examples.

As shown in fig. 1 to 4, a filling machine includes a machine body 1 having a storage space, a plurality of working water tanks 2, a main water tank 3, a lifting mechanism for moving the working water tanks 2 up and down, and a conveying mechanism; the working water tank 2 is arranged in the storage space of the machine body 1; the main water tank 3 is connected with the working water tank 2 through a flow divider 4; the lifting mechanism is arranged at the top of the machine body 1; conveying mechanism sets up in the outside of organism 1, conveying mechanism loads and has a plurality of containers 5 of treating the filling, and every work water tank 2 leads to pipe and its container 5 intercommunication that corresponds, the water pipe is equipped with first valve.

The invention is mainly applied to liquid filling; the lifting mechanism is used for driving the working water tank 2 to lift, the container 5 is filled in the whole filling process by utilizing the gravity principle, and the filling line can be well determined by lifting the height by utilizing the height difference, so that the container 5 is filled; in the invention, the working water tank 2 and the main water tank 3 are communicated through the flow divider 4, so that the amount of liquid entering the working water tank 2 can be equalized, and a plurality of containers 5 to be filled can be ensured to be filled at the same time; in the working process, the occupied area is very small, various parts forming the filling machine are convenient to install, and the production efficiency of the filling production line is improved well.

In order to better use the invention, a bearing plate 6 is arranged in the storage space; the working water tank 2 is arranged on the bearing plate 6; the bearing plate 6 is connected with the transmission end of the conveying mechanism. The working water tank 2 is arranged on the bearing plate 6, so that the conveying mechanism can well and conveniently move the working water tank 2 up and down; this eliminates the need for a separate connection of the conveying means to the working water tank 2, thereby reducing the workload of the worker.

In order to better use the invention, the conveying mechanism comprises a driving wheel 7 arranged at two ends of the top of the machine body 1, a driven wheel 9 arranged at the bottom of the storage space of the machine body 1 and a motor 11; the two driving wheels 7 are connected through a first synchronous shaft 8; the two driven wheels 9 are connected through a second synchronizing shaft 10; the driving end of the motor 11 is connected with any one driving wheel 7 through a coupler; the driving wheel 7 at any side is connected with the driven wheel 9 arranged at the same side of the machine body 1 through a synchronous belt 12; one end of the bearing plate 6 is connected with one synchronous belt 12, and the other end is connected with the other synchronous belt 12. The conveying mechanism is a mechanism which mainly enables the working water tank 2 to generate vertical displacement; utilize motor 11 to drive action wheel 7 and rotate to make the belt rotatory around action wheel 7 and follower 9, at this moment, owing to hold the dress board 6 and the belt is connected, consequently, thereby the belt can drive and hold the action realization upper and lower displacement of dress board 6 following the belt, and such setting is simple easily to be realized.

In the actual use process, the motor 11 disclosed in this embodiment is a forward and reverse rotation stepping motor 11, which can realize displacement control and forward and reverse rotation, and the worker can use a program to program for automatic control according to actual requirements.

In order to better use the invention, one side of any driving wheel 7 is provided with a first bearing seat 13; the first synchronizing shaft 8 passes through two first bearing blocks 13 simultaneously; one side of any driven wheel 9 is provided with a second bearing seat 14; the second bearing housing 14 passes through both second bearing housings 14 simultaneously. The arrangement of the first bearing seat 13 and the second bearing seat 14 well ensures the working efficiency of the first synchronizing shaft 8 and the second synchronizing shaft 10, so that the two synchronizing shafts can well realize interference-free rotation, and the driving wheel 7 is mainly prevented from directly bearing, thereby well providing the bearing capacity of the invention.

For better use of the invention, the conveying mechanism comprises a filling platform 15 for loading the containers 5, a conveying main board 16, a conveying plug board 17 and a platform 18 to be filled; one end of the filling platform 15 is positioned below the water outlet of the water pipe; the conveying main board 16 is positioned at one end of the filling platform 15 and is connected with the filling platform 15 in a sliding manner; the conveying inserting plate 17 is positioned at the other end of the filling platform 15 and is in sliding connection with the filling platform 15; one end of the platform to be filled 18 is connected with one end of the filling platform 15 far away from the water pipe, and the other end is provided with a bottle pushing plate 19; a gap for the conveying insertion plate 17 to slide in is arranged between the filling platform 15 and the platform 18 to be filled; the conveying main board 16, the conveying plug board 17 and the bottle pushing board 19 are all provided with automatic push rods for driving the conveying main board, the conveying plug board 17 and the bottle pushing board to move. The invention uses the conveying mechanism to continuously send the container 5 to be filled to the filling machine for filling; the filling platform 15 is positioned at the lower side of the water outlet of the water pipe, and after the container 5 is placed on the filling platform 15, the bottle mouth of the container 5 just faces the water outlet of the water pipe; the main conveying plate 16 can convey the filled containers 5 out of the filling platform 15; the conveying insertion plate 17 can limit the containers 5 which are just placed in the filling platform 15, so that the interference of other containers 5 to the filling process is avoided; when the conveying main board 16 sends the filled container 5 out of the filling platform 15, the conveying inserting board 17 is pushed to exit the filling platform 15 together, so that only the filled container 5 is sent out of the filling platform 15 after each filling is finished; the bottle pushing plate 19 can push the container 5 on the platform 18 to be filled into the filling platform 15, and then the conveying main plate 16 and the conveying inserting plate 17 are used for tidying the container 5, and then filling is carried out, and the steps are repeated.

It should be noted that all the containers 5 are arranged in a row on the filling platform 15, and the width of a whole row of containers 5 matches the width of the filling platform 15, so that the containers 5 to be filled in the production line can be well aligned with the water outlet of the water pipe after entering the filling platform 15.

In order to better use the invention, baffles 20 are arranged on two sides of the platform 18 to be irrigated; any baffle 20 is provided with a through hole; the conveying mechanism further comprises an alignment plate 21; one end of the inserting and aligning plate 21 extends into the platform 18 to be irrigated through the through hole; the aligning plate 21 is also provided with an automatic push rod for driving the aligning plate to move. The aligning plate 21 and the conveying insert 17 have similar functions, and the aligning plate 21 can align the containers 5 to be filled; the containers 5 are also arranged in rows on the platform 18 to be filled, and after the inserting and aligning plates 21 extend into the platform 18 to be filled, the inserting and aligning plates 21 are squeezed between two adjacent rows of containers 5, so that the containers 5 are arranged in order.

For better use of the invention, the filling platform 15 is arranged in the middle of the machine body 1. The invention realizes the filling of the container 5 by using height drop, therefore, the filling platform 15 should be positioned in the middle of the machine body 1, and therefore, when the working water tank 2 is positioned at the bottom of the machine body 1, the working water tank 2 is filled with water from the main water tank 3; when the position of the working water tank 2 is not lower than that of the filling platform 15, the water discharge of the working water tank 2 can be realized; when the working water tank 2 is located at the highest position where the lifting mechanism can be raised, the water in the working water tank 2 can be completely put.

For better use of the invention, the top of any one of the working water tanks 2 is provided with a water inlet and is communicated with the main water tank 3 through a flow divider 4; the top of any one working water tank 2 is also provided with an exhaust port; the bottom of any water tank is provided with a water outlet. In fact, because the water inlet and the water outlet of the working water tank 2 are respectively positioned at the top and the bottom of the working water tank, and the positions of the main water tank 3 and the filling platform 15 are unchanged, the filling of the container 5 can be realized by utilizing the height difference well, and the water supplement of the working water tank 2 is also realized; the setting of gas vent can be fine the pressure between the inside and the outside of balanced work water tank 2 to guarantee that business turn over water is unobstructed.

For a better use of the invention, the inlet of the working water tank 2 is provided with a second valve. Both the second valve and the first valve in the water line allow the operator to freely select the number of containers 5 to be filled at the time, i.e. the number to be filled at a time, depending on the actual situation.

For better use of the present invention, the bottom of the machine body 1 is provided with universal wheels having brake devices. Because the volume of the filling machine is smaller, the universal wheels are arranged, so that a worker can conveniently move the filling machine to a proper use position, and the filling machine is very convenient.

When the invention is used specifically, as shown in fig. 5 to 7, the lifting mechanism actually has three working states, namely an initial position state, a water discharge control state and a working water tank 2 emptying state; the lifting mechanism can be divided into five lines from lowest to highest; the first line is named as an initial position line 22, and the main water tank 3 supplies water to the working water tank 2 at the moment; the second line is the main water tank water level line 23, and as long as the water line is higher than the water line in the working water tank 2, the main water tank 3 can be continuously filled with water towards the working water tank 2; the third line is a water discharging water level line 24, the working water tank 2 is driven by the lifting mechanism to move up and down, and when the position of the working water tank 2 is higher than the position of the container 5 on the filling platform 15, the working water tank 2 can start to fill and supply water into the container 5; because the liquid height determines the pressure difference, the distance of any end on the water discharging level line 24 can determine how much water is filled into the container 5 from the working water tank 2 to the bottom, and therefore, the distance can determine a fourth line and a water discharging precision adjusting line 25; when the working water tank 2 is located at the highest position where the lifting mechanism can lift, the water of the working water tank 2 can be emptied, which is the emptying water clearing line 26.

In the above five lines, the position between the first line and the second line is the initial position state, the third line to the fourth line is the water discharge control state, and the position of the fifth line is the emptying state of the working water tank 2. After the working water tank 2 is emptied, or after the water is discharged and stops when reaching the preset lifting height, the working water tank returns to the initial position, the water is supplied by the main water tank 3, and the process of the circulation is the working process of the embodiment.

It should be noted that the lifting mechanism is provided with an automatic control system for controlling the rotation and stop of the motor 11, so as to achieve the lifting function of the lifting mechanism; in addition, the water discharge precision adjusting line 25 is based on the prenatal test conditions of different devices.

As shown in fig. 8 to 14, in the normal operation of the conveying mechanism, there are seven operating states; the first working state is a locking state, in which the conveying main board 16 and the conveying plug board 17 lock the containers 5 in the same row on the filling platform 15, and the positioning holes start to be filled; the second working state is a sending-out state, and after the container 5 is filled, the conveying main board 16 pushes the container 5 with the conveying plugboard 17 out of the filling platform 15 to enter the next working procedure; the third working state is a return state, and the conveying plugboard 17 and the conveying main board 16 return to the first state at the same time, so that the next row of containers 5 to be filled are ensured to be flat; the fourth working state is a preparation state, and the conveying flashboard 17 pushes out the filling platform 15 at the moment, so that the next row of containers 5 to be filled can smoothly enter the filling platform 15; the fifth working state is that the container 5 enters a state, at the moment, the bottle pushing plate 19 works to push the next row of containers 5 to be filled out of the filling platform 15; the sixth working state is a secondary locking state, extends into the filling platform 15 from the conveying inserting plate 17, locks the row of containers 5 and starts filling; the seventh operating state is a secondary discharge state, in which the row of filled containers 5 is pushed out of the filling platform 15.

The filling work is completed through the seven continuous state works, and the production line can be formed through continuous circulation. In the above operating states, the lifting mechanism is in the initial position state, except for the locked state and the secondary locked state, which are in the discharge control state and/or the working tank 2 empty state. In the above state, the aligning plate 21 may be used.

It should be noted that, an automatic control system is also provided in the conveying mechanism to control the automatic operation of the automatic push rod, and the automatic control system can be combined with the automatic control system of the lifting mechanism.

It should be noted that both the filling station 15 and the station 18 to be filled belong to a large station for placing the containers 5, so that the filled containers 5 are pushed out of the filling station 15 without risk of falling and are subsequently transported to the next process.

The invention is not limited to the above alternative embodiments, and any other various forms of products can be obtained by anyone in the light of the present invention, but any changes in shape or structure thereof, which fall within the scope of the present invention as defined in the claims, fall within the scope of the present invention.

Claims

1. A filling machine, comprising:

a body (1) having a storage space;

the working water tanks (2) are placed in the storage space of the machine body (1);

the main water tank (3) is connected with the working water tank (2) through a flow divider (4);

the lifting mechanism enables the working water tank (2) to move up and down and is arranged at the top of the machine body (1); and

the conveying mechanism is arranged outside the machine body (1) and is loaded with a plurality of containers (5) to be filled;

wherein, every work water tank (2) leads to pipe rather than the container (5) intercommunication that corresponds, the water pipe is equipped with first valve.

2. A filling machine as claimed in claim 1, characterized in that a receiving plate (6) is provided in said storage space; the working water tank (2) is arranged on the bearing plate (6); the bearing plate (6) is connected with the transmission end of the conveying mechanism.

3. A filling machine as defined in claim 2 wherein said conveying mechanism comprises:

the two driving wheels (7) are arranged at the two ends of the top of the machine body (1), and the two driving wheels (7) are connected through a first synchronous shaft (8);

the driven wheels (9) are arranged at the bottom of the storage space of the machine body (1), and the two driven wheels (9) are connected through a second synchronous shaft (10); and

the driving end of the motor (11) is connected with any one driving wheel (7) through a coupler;

wherein, the driving wheel (7) at any side is connected with a driven wheel (9) arranged at the same side of the machine body (1) through a synchronous belt (12); one end of the bearing plate (6) is connected with one synchronous belt (12), and the other end of the bearing plate is connected with the other synchronous belt (12).

4. A filling machine as claimed in claim 3, characterized in that one side of any one of the drive wheels (7) is provided with a first bearing block (13); the first synchronizing shaft (8) passes through two first bearing blocks (13) simultaneously;

one side of any driven wheel (9) is provided with a second bearing seat (14); the second bearing block (14) passes through both second bearing blocks (14) simultaneously.

5. A filling machine as defined in claim 1 wherein said conveying mechanism comprises:

a filling platform (15) for loading the container (5), one end of the filling platform (15) is positioned below the water outlet of the water pipe;

the conveying main board (16), the conveying main board (16) is positioned at one end of the filling platform (15) and is connected with the filling platform (15) in a sliding manner;

the conveying inserting plate (17) is positioned at the other end of the filling platform (15) and is in sliding connection with the filling platform (15); and

a platform (18) to be filled, wherein one end of the platform (18) to be filled is connected with one end of the filling platform (15) far away from the water pipe, and the other end of the platform (18) to be filled is provided with a bottle pushing plate (19);

wherein a gap for the conveying inserting plate (17) to slide in is arranged between the filling platform (15) and the platform (18) to be filled; the conveying main board (16), the conveying plug board (17) and the bottle pushing board (19) are all provided with automatic push rods for driving the conveying main board, the conveying plug board (17) and the bottle pushing board to move.

6. A filling machine as claimed in claim 5, characterized in that said platform (18) to be filled is provided on both sides with baffles (20); any baffle (20) is provided with a through hole;

the conveying mechanism further comprises an inserting and aligning plate (21); one end of the inserting and aligning plate (21) extends into the platform (18) to be irrigated through the penetrating hole; the inserting and aligning plate (21) is also provided with an automatic push rod for driving the inserting and aligning plate to move.

7. A filling machine as claimed in claim 5, characterized in that said filling platform (15) is arranged in the middle of the machine body (1).

8. A filling machine as claimed in claim 1, characterized in that the top of any one of the working tanks (2) is provided with a water inlet and is connected to the main tank (3) through a diverter (4); the top of any one working water tank (2) is also provided with an exhaust port; the bottom of any water tank is provided with a water outlet.

9. A filling machine as claimed in claim 8, characterized in that the inlet of the working water tank (2) is provided with a second valve.

10. A filling machine as claimed in claim 1, characterized in that the bottom of said machine body (1) is provided with universal wheels with braking means.