Field of the Invention

The present invention relates to a rear wheel cover of a cart for transporting goods, wherein more particularly, it relates to a universal cover that allows variable use of front and rear wheels having both the same and different diameters relative to each other.

Background of the Invention

Carts or containers for transporting goods, typically used for supplying the trade, are in the current state of the art provided with front and rear wheels, wherein the front pair of wheels is most often implemented as rotatable, while the rear pair of wheels is implemented as fixed, i.e., turning of the rear wheels to the sides is not allowed. Metal pieces are used to attach the rear wheels to the frame of the cart which at the same time function as the rear wheel covers since they protect these wheels from external impacts. Such impacts can occur, e.g., during careless handling of the containers using a pallet cart.

The rear wheel cover (commonly referred to as "wheel cover" or "wheel box") is in the current state of the art most often implemented in a double-walled embodiment. That means that it includes a top wall which is used for attachment, typically welding, to the frame of the cart, and further also two side walls which extend downwards from the opposite edges of the top wall, thus covering the wheels on both lateral sides. These side walls are provided opposite each other with openings for fastening the rear wheel, wherein the dimensions of the side walls, and especially the location of the respective opening, depend on the diameter of the wheels being fastened. The wheels having a diameter of 100mm and 125mm are standardly used. Currently, three basic types of these double-walled covers exist. The first type is chosen if the rear wheels having a diameter of 100mm are to be fastened to the cart, wherein the rotatable front wheels also have the same diameter, i.e., 100mm. The location of the opening for attaching the rear wheels for this type of cover is made at such height that after providing the cart with 100mm wheels, the bottom of the cart is oriented parallel to the floor. Another type of the cover is chosen if the rear and front wheels having a diameter of 125mm are to be fastened to the cart, because other (higher) front forks are used for fastening the 125mm front wheels than for fastening the 100mm front wheels. The last type of the cover is then used for carts that are provided with wheels having a diameter of 100mm at the front and wheels having a diameter of 125mm at the back, wherein, as with the two previous types, the relevant opening in the side wall of the cover is also made at such height so that the bottom of the cart provided with these wheels is oriented parallel to the floor, i.e., not inclined towards it.

Therefore, for each combination of the wheels used (i.e., 100mm at the front and 100mm also at the back; 125mm at the front and 125mm also at the back; 100mm at the front and 125mm at the back), it is necessary to have a certain type of rear wheel cover available, which is very disadvantageous, especially for the cart manufacturers. In order to be able to react flexibly to the customer's orders, i.e., the buyer of the carts, the manufacturer must have a sufficient quantities of each type ready in stock. Storing significant quantities is very expensive, regardless of the fact that the manufacturer may not even have sufficient storage capacity. Therefore, the manufacturer often keeps only a limited number of pieces in stock which can cause problems with the orders, e.g., the manufacturer is forced to reject certain orders, thereby losing part of the profit. Another option is to manufacture and complete a required number of carts directly to the customer's order, however, even in this case, the variability of three different types of covers is a complication for the effective manufacturing. Another disadvantage of said double-walled wheel boxes lies in the fact that they do not provide a very high resistance to the external pressure on their own. For example, frequent impacts from the pallet carts or other devices can cause deformation of the side walls. Thus, to minimalize this undesirable effect, the metal reinforcements can be welded between these side walls.

Patent document EP0768229 B1 discloses a solution of a cart with a collapsible bottom, in which the rear wheel covers are used, wherein two openings are made above each other in these covers. However, said document does not describe these openings in more detail, it only states that these are openings for the wheel shaft. It can be, e.g., two openings for attaching the rear wheels having different diameters, in any case, the found document does not disclose any instructions for assembling the universal solution of the rear wheel cover, which would allow variable use of front and rear wheels with both the same and different diameters relative to each other in the three important above- mentioned combinations. The above-mentioned disadvantages thus persist. The solution of double-walled wheel box with two openings above each other is also disclosed by a German industrial design with the registration number 40204247.

Therefore, it would be suitable to come up with a solution of the rear wheel cover of the cart for transporting goods which would allow using the combination of front and rear wheels with both the same and different diameters relative to each other so that the bottom of the cart provided with a certain combination of front and rear wheels is always oriented parallel to the floor, i.e., not inclined towards the floor. Especially, it would be suitable to come up with a solution that would remove the need for three different rear wheel covers for individual combinations of front and rear wheels. The new solution should also be characterized by high mechanical resistance.

Summary of the Invention

The above-mentioned disadvantages are, to a certain extent, removed by a rear wheel cover of a cart for transporting goods provided with front and rear wheels including a top wall adapted for attachment to a frame of the cart and two side walls extending from the top wall, wherein the rear wheel cover is adapted for fastening the first type of wheels or the second type of wheels, wherein the first type of wheels and the second type of wheels have different radii. The essence of the cover according to the present invention lies in that each of these two side walls includes a first opening, a second opening, and a third opening adapted for fastening the rear wheel shaft and made at different distances from the top wall, wherein the distance of the second opening from the top wall is larger than the distance of the first opening from the top wall and smaller than the distance of the third opening from the top wall. The difference in distance of the second opening from the top wall and the first opening from the top wall is equal to the difference in radius of the first type of wheels and the second type of wheels.

Due to three conveniently placed openings, the rear wheel cover is characterised by a high universality, because it allows the use of three different combinations of front and rear wheels. Just one of the openings in the rear wheel cover is intended for each of these combinations (i.e., 100mm at the front and 100mm also at the back; 125mm at the front and 125mm also at the back; 100mm at the front and 125mm at the back). Thus, depending on the desired combination, it is only necessary to choose the respective opening into which the rear wheel shaft is to be fastened, and it is ensured that the bottom of the cart is oriented parallel to the floor. The universal rear wheel cover offers an advantage, especially for the manufacturer of these covers (so-called wheel boxes), since the manufacturer does not need to have a stock of covers prepared separately for each combination. This can save storage capacity, decrease storage costs and at the same time increase the manufacturer's ability to react flexibly to customer's orders.

The difference in distance of the second opening from the top wall and the first opening from the top wall is preferably equal to 12.5mm, wherein the difference in distance of the third opening from the top wall and the second opening from the top wall is also equal to 12.5mm. Said distance of the openings is preferred mainly because it corresponds to the commonly used dimensions of front and rear wheels. Typically, these wheels have a diameter of 100mm (the first type of wheels) or 125mm (the second type of wheels), wherein the distance of the individual openings of 12.5mm therefore corresponds to the half of the difference in diameter of these used types of wheels, or to the difference in radius thereof.

At least one of the first opening, the second opening and the third opening is preferably displaced relative to others in a direction parallel to the top wall. By displacing at least one of the openings (for example, the second opening) relative to other openings, the risk of damaging the openings is minimalized. Therefore, this displacement reduces the places having a very thin layer of metal material which are formed between the edges of the relevant openings.

At least one of the first opening, the second opening and the third opening is preferably turned relative to others. Similarly to the displacement of at least one of the openings, even a suitable turning of the openings ensures that between the edges of the individual openings a larger layer of material of the cover is located, which is therefore more mechanically resistant.

The cover according to the present invention includes depressions preferably on the top wall and/or at least on one side wall. These depressions increase the mechanical resistance of the cover and in particular to the external impacts and deformations, which can occur, e.g., due to careless handling of the pallet carts.

The cover according to the present invention preferably includes reinforcements connecting the side walls. These reinforcements substantially form two additional side walls of the cover, thereby again contributing to the higher mechanical resistance to the external impacts and deformations. The reinforcements are preferably an integral part of the cover, and thus there is no need to weld them to the side walls.

Each reinforcement preferably includes a first wing and a second wing, wherein the first wing extends from the first side wall and the second wing extends from the opposite side wall, wherein the first wing and the second wing are connected to each other by a joint. By connecting the first and second wing, the solid reinforcement, which increases the mechanical resistance of the cover, is created. Since the wings extend directly from the side walls of the cover, only one joint is needed to form a solid reinforcement, for example a weld.

The joint is preferably implemented as a shaped lock. As a result, it is not necessary to weld the wings together.

Description of the Drawings

The summary of the invention is further clarified using examples of embodiments thereof, which are described using the accompanying drawings, in which:

Fig. 1 shows a rear wheel cover of a cart for transporting goods in the first exemplary embodiment according to the present invention, in a side view and with the plane of the section A-A marked, Fig. 2 shows a rear wheel cover in the first exemplary embodiment according to the present invention, in a top view of a top wall of the rear wall cover,

Fig. 3 shows a rear wheel cover in the first exemplary embodiment according to the present invention, in the front view of a reinforcement,

Fig. 4 shows a rear wheel cover in the first exemplary embodiment according to the present invention, in section A-A.

Fig. 5a shows a part of a side wall of a rear wheel cover according to the present invention having three openings in the first embodiment,

Fig. 5b shows a part of a side wall of a rear wheel cover according to the present invention having three openings in an alternative embodiment,

Fig. 5c shows a part of a side wall of a rear wheel cover according to the present invention having three openings in another alternative embodiment, and

Fig. 5d shows a part of a side wall of a rear wheel cover according to the present invention having three openings in another alternative embodiment.

Exemplary Embodiments of the Invention

The invention will be further clarified using examples of the embodiments with reference to respective drawings.

In the first exemplary embodiment, a rear wheel cover 1 according to the present invention includes a top wall 1 a which is used to attach the rear wheel cover 1. to a frame of the cart, and further two side walls 1 b which are used to fasten a rear wheel shaft to the rear wheel cover 1_. As can be seen, e.g., in Fig. 3 or Fig. 4, said two side walls 1 b extend individually from two opposite edges of the top wall 1 a and lead down in a direction approximately perpendicular to the top wall 1 a in such way that both side walls 1 b are arranged at a distance from each other, defining a space for the rear wheel. Thus, in the front view of Fig. 3 and Fig. 4, the rear wheel cover 1 in the first exemplary embodiment has approximately a shape resembling an inverted letter U, because the side walls b extend from the top wall 1 a in such way that the location of their connection is rounded, and thus does not include a sharp corner. Alternatively, however, the connection of the side walls 1 b to the top wall 1 a however can include such sharp corners.

The side walls 1 b in the first exemplary embodiment are implemented in mirror symmetry to each other, wherein their distance from each other varies from first end thereof, i.e., from the location where they extend from the top wall 1 a, to their second, i.e. free, end. As can be seen in Fig. 4, the side walls 1 b in the shown section include successively three parts having different distances from each other, wherein a bevel or a jump is located between these parts. Such shape in the section of Fig. 4 is a result of the side walls 1 b including depressions 4, which can be best seen in Fig. 1 , and which make the rear wheel cover 1 more mechanically resistant, and in particular more resistant to external impacts and deformations which can occur, e.g., due to careless handling of the pallet carts. Alternatively, the outer walls 1 b have different shape if this forming allows the rear wheel shaft to be reliably fastened to the outer walls 1 b in such way that these side walls 1 b provide a sufficient space for the rear wheel being fastened and that the side walls 1 b at least partially cover the rear wheel on its both lateral sides.

The top wall 1 a in the first exemplary embodiment is implemented in approximately rectangular shape, wherein it includes two longer edges from which the individual side walls 1 b extend, as described above, and also two shorter edges from which, in the first exemplary embodiment, no other walls of the rear wheel cover 1 extend. The rectangular shape of the top wall 1 a is disrupted, as can be seen in top view of Fig. 2, by additional depressions 4 to increase the mechanical resistance. In the first exemplary embodiment of Fig. 1 to Fig. 4, the rear wheel cover 1 includes four depressions 4 on the top wall 1 a which also protrude into respective side walls 1 b and are located in the area of the rounded transition between the top wall 1 a and the side walls 1 b. Alternatively, the rear wheel cover 1. includes a different number of these depressions 4, or there depressions 4 are arranged at different locations of the rear wheel cover 1 or implemented in different shape than shown in Fig. 1 to Fig. 4. Alternatively, the rear wheel cover 1 does not include any depression 4, wherein, in this embodiment, the mechanical resistance of the rear wheel cover 1 is lower than in the first embodiment.

The top wall 1 a of the rear wheel cover 1 includes a bottom side and a top side, wherein the top side of the top wall 1 a is used for attachment to the frame of the cart for transporting goods. The embodiment of the frame of the cart can vary depending on the type and purpose of the cart, wherein the frame can be implemented e.g., as so-called A- frame, that is, a frame including two side parts that are oriented differently relative to each other. The A-frame is thus narrower on its front side than on its rear side, and its shape thus substantially resembles a shape of the letter A. Typically, the rear wheel cover 1. is welded to the frame of the cart, alternatively, however, this fastening can be implemented in another manner, e.g., by screwing. Alternatively, the top wall 1 a is implemented in different than approximately rectangular shape, if such shape allows the rear wheel cover 1 to be reliably fastened to the frame of the cart and if the rear wheel cover 1 with such top wall 1 a provides a sufficient space for the rear wheel.

In the first exemplary embodiment, the rear wheel cover 1. further includes two reinforcements 2 which connect the side walls 1 b on both their side edges and thus substantially form two additional side walls of the rear wheel cover 1, as can be seen e.g., in Fig. 2. In the first exemplary embodiment according to the present invention, each reinforcement 2 includes a first wing 2a and a second wing 2b which are connected to each other by a joint 5. As can best be seen in Fig. 2, two first wings 2a extend from the first side wall 1 b on its two side edges, and two second wings 2b extend from the second, opposite, side wall 1 b on its two side edges. At the location of the connection with the side walls 1 b, these first wings 2a and second wings 2b can be rounded, wherein, alternatively, they can be curved sharply to a right angle, or they can extend from the side edges of the side walls 1 b in a perpendicular direction opposite each other. The first wings 2a and the second wings 2b are thus an integral part of the rear wheel cover 1 and thus do not need to be additionally welded to the rear wheel cover T

The first wing 2a and the second wing 2b are directed opposite each other and are connected to each other by the joint 5, shown in Fig. 3 or Fig. 4. This joint 5 is implemented in the first exemplary embodiment as a shaped lock, i.e., e.g., as a puzzletype connection, wherein the first wing 2a includes a protrusion and the second wing 2b includes a recess complementary in shape to the shape of the protrusion. By securing the protrusion into the recess, a connection of the first wing 2a and the second wing 2b to each other is implemented, wherein connecting the first wing 2a and the second wing 2b forms a solid reinforcement 2 interconnecting both side walls 1 b of the rear wheel cover 1_. This reinforcement 2 increases the resistance of the rear wheel cover 1. to the mechanical deformation, in particular to the external impacts which can occur, e.g., due to careless handling of the pallet cart. Alternatively, the joint 5 is not implemented as a shaped lock, but it is implemented, e.g., as a weld, i.e., the solid reinforcement 2 is formed by welding the first wing 2a and the second wing 2b together. Alternatively, the joint 5 is implemented such that the first wing 2a and the second wing 2b are glued to each other. Alternatively, the reinforcement 2 is implemented as a solid piece and thus does not include the first wing 2a and the second wing 2b described above, wherein this reinforcement 2 is connected to the side edges of the side walls 1 b of the rear wheel cover 1_. This connection can then be implemented, e.g., as a weld.

Alternatively, the rear wheel cover 1 includes only one reinforcement 2, or does not include any reinforcement 2, however, in such embodiments, the rear wheel cover 1. is characterised by lower mechanical resistance than in the first exemplary embodiment.

In the first exemplary embodiment, both side walls 1 b of the rear wheel cover 1. further include a first opening 3a, a second opening 3b and a third opening 3c opposite each other, which are adapted to fasten the rear wheel shaft. As can be best seen in Fig. 1 or in Fig. 5a, the first opening 3a, the second opening 3b and the third opening 3c are made at different heights, i.e., at different distances from the top wall 1 a. The height of the location of the first opening 3a, the second opening 3b and the third opening 3c is chosen in such way that after the rear wheel having a certain diameter has been fastened into one of the first opening 3a, the second opening 3b and the third opening 3c and after the front wheel has been fastened into the fork of the front wheel, the bottom of the cart provided with front wheels and rear wheels is oriented parallel to the floor. While the front wheel is attached to the frame of the cart by one opening in the fork or the front wheel cover, the first opening 3a, the second opening 3b and the third opening 3c made in the side walls 1 b of the rear wheel cover 1 allow the rear wheel shaft to be fastened in three different height positions corresponding to the individual openings.

In the first exemplary embodiment, the centre of the first opening 3a is arranged at a distance of 74.5mm from the top wall 1 a, the centre of the second opening 3b is arranged at a distance of 87mm from the top wall 1 a and the centre of the third opening 3c is arranged at a distance of 99.5mm from the top wall 1 a. The distance from the top wall 1 a means the shortest, i.e., perpendicular, distance between the top wall 1 a and the centre of the relevant opening. In the first exemplary embodiment, the height of the rear wheel cover 1, i.e., the distance from the top edge of the side wall 1 b to the bottom edge of the side wall 1 b, is implemented as 1 10mm long. The rear wheel cover 1. allows the use of front and rear wheels in three combinations, wherein two types of front wheels and two types of rear wheels are combined. The first type of front wheels has a diameter of 100mm in the first exemplary embodiment and the second type of front wheels has a diameter of 125mm in the first exemplary embodiment, i.e., the diameter of the second type of front wheels is larger than the diameter of the first type of the front wheels. Analogously, the first type of rear wheels has a diameter of 100mm in the first exemplary embodiment and the second type of rear wheels has a diameter of 125mm in the first exemplary embodiment, i.e., the diameter of the second type of rear wheels is larger than the diameter of the first type of rear wheels. Thus, in general, the first type of wheels and the second type of wheels can be defined, wherein the first type of wheels thus refers to wheels with a smaller diameter and the second type of wheels refers to wheels with a larger diameter. Thus, the rear wheel cover 1 is adapted for fastening the first type of wheels or the second type of wheels, which means that it includes relevant openings (especially the second opening 3b) for fastening the first type of wheels and relevant openings (especially the first opening 3a and the third opening 3c) for fastening the second type of wheels.

The first opening 3a is used when the cart is provided with front wheels of the first type (having a diameter of 100mm) and rear wheels of the second type (having a diameter of 125mm). The second opening 3b is used when the cart is provided with front wheels of the first type (having a diameter of 100mm) and rear wheels of the first type (having a diameter of 100mm). The difference in height between the first position of the first opening 3a and the second opening 3b in the first exemplary embodiment is 12.5mm which corresponds to the half of the difference in diameter of the first type of wheels and the second type of wheels, therefore to the difference in radius of the first type of wheels and the second type of wheels. The second opening 3b in the rear wheel cover 1 is at the same time located at the same height as the relevant front opening in the cover or the fork of the front wheel, i.e., the distance of the second opening 3b from the top wall 1 a of the rear wheel cover 1. is the same as the distance of the opening in the cover or the fork of the front wheel from its top wall. After the front wheels of the first type (having a diameter of 100mm) have been fastened into the front opening and the rear wheels of the first type (having a diameter of 100mm) have been fastened into the second opening 3b, the parallel orientation of the bottom of the cart with the floor is thus ensured. Due to said difference in height between the position of the first opening 3a and the second opening 3b, which is equal to the half of the difference of the said diameters, the parallel orientation of the bottom of the cart with the floor is also ensured after fastening the front wheels of the first type (having a diameter of 100mm) into the front opening and the rear wheels of the second type (having a diameter of 125mm) into the first opening 3a.

The third opening 3c is used when the cart is provided with front wheels of the second type (having a diameter of 125mm) and rear wheels of the second type (having a diameter of 125mm), wherein it is worth noting here that other (higher) front forks are used for fastening the second type of front wheels than for fastening the first type of front wheels. The difference in height between the position of the second opening 3b and the third opening 3c in the first exemplary embodiment is 12.5mm, however, this difference in height can be also smaller, or bigger than 12.5mm and may not correspond to the difference in radius of the first type of wheels and the second type of wheels. To be more precise, the difference in height between the position of the second opening 3b and third opening 3c is chosen according to the embodiments of the front fork for the first type of wheels and the front fork for the second type of wheels. Particularly, it is chosen according to the fact in which height position in the front fork for the first type of wheels, the front opening is located for fastening the first type of wheels, and in which height position in the front fork for the second type of wheels, the front opening is located for fastening the second type of wheels. In the first exemplary embodiment, these different front forks differ in such way that the distance of the front opening from the top wall of the front fork in case of the front fork for the second type of wheels is 12.5mm larger than the distance of the front opening from the top wall of the front fork in case of the front fork for the first type of wheels. The difference of these distances then corresponds to the difference in height between the position of the second opening 3b and the third opening 3c. After fastening the front wheels of the second type (having a diameter of 125mm) into the front opening of the relevant front fork and the rear wheels of the second type (having a diameter of 125mm) into the third opening 3c, the parallel orientation of the bottom of the cart with the floor is ensured even for this combination of front and rear wheels.

Alternatively, the centre of the first opening 3a is located at a different distance from the top wall 1 a than at a distance of 74.5mm, wherein, alternatively, the height of the rear wheel cover 1. is also smaller or larger than 1 10mm, as described in the first exemplary embodiment. Alternatively, the first and second type of front and rear wheels can also have different diameters than above-mentioned 100mm and 125mm, wherein the difference in height between the position of the first opening 3a and the second opening 3b corresponds to the half of the difference in diameter of the first type of wheels and the second type of wheels, as described already within the first exemplary embodiment. Thereby, the parallel orientation of the bottom of the cart with the floor is ensured in the situations described above.

The arrangement of the first opening 3a, the second opening 3b and the third opening 3c in the first exemplary embodiment can be best seen in Fig. 1 and also in Fig. 5a, which shows only the part of the rear wheel cover 1 including these openings. As can be seen in Fig. 5a, in the first exemplary embodiment, the first opening 3a, the second opening 3b and the third opening 3c have substantially a square shape, wherein the second opening 3b is displaced relative to the first opening 3a and third opening 3c in a direction parallel to the top wall 1 a. Particularly, the second opening 3b is displaced to the right, as can be seen in Fig. 5a, however, it can also be displaced in the opposite direction. Due to this displacement of the second opening 3b, the risk of damaging the openings is minimalised, because the locations with a very thin layer of material, which occur between the edges of the relevant openings, i.e., between the edges of the first opening 3a and the second opening 3b and between the edges of the second opening 3b and the third opening 3c, are reduced.

The locations with a thin layer can be reduced further by turning the second opening 3b relative to other openings, as can be seen in Fig. 5b. In this figure, it can be seen that the distance of the edges of the second opening 3b from the edges of the first opening 3a and the third opening 3c is larger than in the embodiment of Fig. 5a. Alternatively, additional or all openings can also be turned, as shown in Fig. 5c, resulting in further reduction of the locations with the thin layer of material and minimalization of the risk of damaging the openings. Alternatively, it may not be only the second opening 3b that is displaced in a direction parallel to the top wall l a, although such embodiment is substantially the most preferred, since by moving only this second opening 3b, the reduction of the locations with the thin layer of material is ensured at both the first opening 3a and the third opening 3c. Alternatively, the first opening 3a, the second opening 3b and the third opening 3c may be arranged in one row. Alternatively, the first opening 3a, the second opening 3b and the third opening 3c can have a shape other than square, e.g., circular shape, as shown in Fig. 5d, or any other shape or dimension, if such shape or dimension allows the rear wheel shaft to be reliably fastened to the rear wheel cover 1.

The rear wheel cover 1. is made of metal, e.g., by forming from a metal sheet, wherein the rear wheel cover 1. is made as one solid piece. Within the forming process, the depressions 4 can also be made in the rear wheel cover 1. to increase the mechanical resistance, as described above in the first exemplary embodiment. Alternatively, the rear wheel cover 1 can be made as one solid piece made by forming of the metal sheet in such way that this solid piece does not include reinforcements 2, wherein these reinforcements can be additionally welded to the rear wheel cover 1_. Alternatively, the rear wheel cover 1 can be made by welding its individual parts together, e.g., thus by welding its top wall 1 a and its side walls 1 b together. The relevant openings are cut or punched into the made rear wheel cover 1_, that is, the first opening 3a, the second opening 3b and the third opening 3c.

In another embodiment, a cut-out can be made in both side walls 1 b. This cut-out is made at least on the front side of the rear wheel cover 1_, wherein, particularly, the cutout is made at the same time from the bottom and side edges of the relevant side wall 1 b. This allows the wheel fastened to the rear wheel cover 1. to overcome various irregularities on the floor, e.g., doorsills.

Industrial Applicability

A solution of a rear wheel cover of a cart for transporting goods described above can be used for different types of carts (containers) for transporting goods, e.g., for carts with different embodiments of the frame. List of Reference Numerals

1 - rear wheel cover

1 a - top wall

1 b - side wall

2 - reinforcement

2a - first wing

2b - second wing

3a - first opening

3b - second opening

3c - third opening

4 - depression

5 - joint