GB2437273A

GB2437273A - A conveying wheel with resilient suspension

Info

Publication number: GB2437273A
Application number: GB0705133A
Authority: GB
Inventors: Christian Eriksson
Original assignee: Oy Mannerin Konepaja AB
Current assignee: Oy Mannerin Konepaja AB
Priority date: 2006-04-21
Filing date: 2007-03-16
Publication date: 2007-10-24
Anticipated expiration: 2027-03-16
Also published as: FI7127U1; GB0705133D0; DE102007012466A1; GB2437273B; FIU20060182U0

Abstract

The wheel comprises a wheel body (11), a bearing (13) mounted in the wheel body, by which bearing the wheel (10) is bearing-mounted on a shaft (17), and a spring suspension (15a, 15b) provided by flexible elements integrated into the wheel structure. The elements are fitted to be coupled to the inner race of the bearing (13) in between the wheel body (11) and the shaft (17) so that they do not rotate. On the shaft (17) a non-rotating internal seal (16a, 16b) is mounted and, correspondingly, on the internal race of bearing (13) a non-rotating external seal (14a, 14b) is mounted, and in between said internal and external seals each flexible element (15a, 15b) is mounted in a non-rotating manner. The seals (14a, b, 15a, b) can be axially split to enable assembly on either side of the bearing (13).

Description

Conveying wheel The invention concerns a conveying wheel, which

comprises a wheel body, a bearing mounted in the wheel body, by which bearing the w heel is bearing-mounted on a shaft, and a spring suspension integrated into the wheel structure.

Conventional wheels, such as those used in roller cages, various kinds of wheel barrows and other such, are usually of a fixed and rigid structure, for example, in such a way that such a wheel comprises a wheel hub made of metal or of some plastic material suitable for the purpose, on which hub a wearing surface is cast directly, that is, a "tyre" made of polyurethane or some other such material. The wheel hub is bearingmounted on a shaft, which is attached to a fixed or turning fork. Such a wheel structure causes some problems and drawbacks, of which noisiness can be mentioned as a first example. The noisiness of the wheel is especially obvious when using the wheel on a rough floor or ground and, for example, on a tiled floor. Use on a rough ground and on a tiled floor is also associated with another drawback, which is vibration. Vibration causes an cssential problem, if the conveyed goods are fragile. Vibration is also a load on the wheel fork and on the device, such as a roller cage or wheel barrow, to which it is attached. Vibration and noisiness can be reduced to some extent by making the wheel's wearing surface of a softer material. A soft wearing surface again will reduce the usability and controllability of the device, such as a roller cage, because when the wheel is loaded the wearing surface will yield and the contact surface between the wheel and the ground or floor will spread out over a larger area. A wheel of this kind with a soft wearing surface is not either so easy to move as a wheel with a hard surface, but the wheel with a soft surface has a higher rolling friction. In addition, a conveying wheel with a hard surface is easier to push in a side direction, because there is less friction against the ground or floor.

Efforts to solve the vibration problem have also been made by arranging a spring suspension in the wheel fork, but this will result in a complicated structure due to several parts.

Efforts have also been made to reduce vibration and noise in such a way that the wheel proper is made with spring suspension by arranging some flexible element or some other such spring suspension in the wheel body. Such solutions have been presented earlier, for example, in patent and application publications EP 0720923, EP 0555808 and GB 608615, to highlight just a few examples. The structure of these wheels is usually such that a rigid wheel hub or the wheel body is bearing-mounted in quite a conventional manner on a shaft with the aid of bearings. On the hub or body a flexible element, a "spring suspension", is arranged and on this there is the wheel's wearing surface, which is of a relatively hard material. The wearing surface is generally relatively thin compared with the wheel diameter, and for this reason the material of the wearing surface must be very hard, as otherwise together with the flexible element it would adapt too much to the shape of an uneven ground or floor, which for its part would lead to a high rolling resistance. Another drawback is also that the flexible element rotating with the wheel becomes hot during use on account of internal friction, and this again will heat the wearing surface and thus cause an elliptic shape. This again results in an increasing rolling resistance. The state-of-the-art wheel will also become elliptic after standing loaded and motionless for a long time.

The purpose of the present invention is to bring about a conveying wheel, which is improved and of a new kind and which is equipped with spring suspension. To bring about this, the invention is mainly characterized in that a flexible element achieving the spring suspension for the wheel is fitted in the radial direction of the wheel inside the bearing, in between the wheel body and the shaft.

On the shaft of the wheel a non-rotating internal seal is preferably mounted and on the internal race of the wheel bearing a non-rotating external seal is mounted, and the flexible element achieving the spring suspension for the wheel is mounted in between said internal and external seals in a non-rotating manner.

The flexible element consists of two parts, which parts are fitted on opposite sides of the wheel's mid-line. The parts of the flexible element may hereby be located symmetrically in relation to the wheel's mid-line. The flexible element preferably comprises two flexible rings. Alternatively, the flexible element may also be formed in one piece or, on the other hand, the flexible element may consist of several separate pieces.

In order to facilitate assembly of the wheel, the internal and external seals consist of two parts in such a way that the seal halves can be mounted in their places from opposite sides in the axial direction of the wheel.

The external surface of the wheel body may mount a coating functioning as the wearing surface, or said external surface may as such function as the wheel's wearing surface.

In comparison with the state of the art, the invention achieves several advantages, of which the following may be mentioned, among others. In the invention, the flexible component achieving the elasticity is located in the radial direction inside the wheel bearing, whereby it does not rotate. Thanks to the non-rotating feature the structure will not become hot or warm. The rigid body of the wheel is located outside the bearing and the flexible component, whereby the wheel will keep its shape even under heavy loads and also after having stood in its place for a long time. The flexible component has a low mass and a small cross-sectional area, whereby it will only require small forces to flex. The flexible component also provides the wheel with lateral springiness. The properties of the wheel's wearing surface material or tyre material, especially the hardness, can be chosen more freely than in state-of-the-art solutions, because the wheel body provides the structure with the necessary rigidity. Rigidity need not be sought in a hard surface material. Since the shape of the wheel will not change under load, the wheel has less rolling resistance than spring-suspended state-of-the-art wheels, whereby less energy is needed to move it. The weight of the spring-suspended wheel according to the invention remains low in comparison with state-of-theart solutions. Since the flexible components of the wheel are located inside the bearing, they will protect the bearing-mounting of the wheel at the same time. The spring suspension solution according to the invention dampens the device's vibration and at the same time it reduces the noise made by the wheel. Other advantages and characteristic features of the invention will emerge from the following detailed

description of the invention.

In the following, the invention will be described by referring to the figures in the appended drawing, but there is no intention to restrict the invention narrowly to the examples shown in the figures.

Figure 1 shows a cutaway view of the conveying wheel according to the invention.

Figure 2 shows the conveying wheel according to the invention seen from one side.

In the figures of the drawing, a general reference number 10 indicates the conveying wheel according to the invention. Conveying wheel 10 comprises a wheel body 11, which is made of a rigid and hard material suitable for the purpose. The body may be of metal material, or some suitable plastic material, such as polyamide or other such may be used as body material. The outer surface 12 of the body may be provided with a coating forming the wheel's wearing surface, or the outer surface 12 may as such function as the wheel's 10 wearing surface. If a special wearing surface, a "tyre", is used, its hardness and flexibility can be varied over quite a large range.

Inside the wheel body 11 a bearing 13 is fitted, which in the presented example is a ball bearing. The bearing is mounted at its outer race directly attached to the wheel body 11. On the wheel shaft 17, which as shown in the figure is attached to a fork 18, an internal seal I 6a, 1 6b of some hard material is mounted, and correspondingly an external seal 1 4a, I 4b of some hard material is mounted attached to the internal race of the bearing 13. In between said internal and external seals 16a, 16b; 14a, 14b a flexible element 15a, 15b is mounted to bring about springiness for the wheel. As shown in the cutaway view of Figure 1, the internal and external seals 16a, 16b; 14a, 14b consist of two parts in order to make assembling of the wheel 10 structure easier. In the example shown, the flexible element 15a, 15b also consists of two parts and comprises two flexible rings 15a, I 5b located symmetrically in relation to the midline of the wheel. The flexible element I 5a, I 5b may also have a structure and implementation differing from those shown in Figure 1. Thus, such a solution is also possible, where the rings 1 5a, I 5b of the two-piece flexible element are located asymmetrically on different sides of the wheel's mid-line. Furthermore, the flexible element I 5a, I 5b may be in one piece, or it may consist of more than two parts.

Thus, in accordance with Figure 1, flexible element 15a, 15b is located in the radial direction inside bearing 13, where it is locked in place with the aid of external and internal seals 14a, l4b; l6a, 16b. Flexible element 15a, 15b is thus non-rotating. Furthermore in accordance with Figure 1, the flexible element 1 5a, I 5b has a small cross- sectional area and its mass is also low, whereby it requires only small forces in order to flex. Flexible element 15a, 15b also provides the wheel with lateral springiness, and the springiness, both the radial springiness and the lateral springiness, can be controlled by changing the hardness of the flexible element, that is, by changing the raw material of the flexible element. Since flexible element 15a, 15b is located inside bearing 13, wheel 10 will keep its shape also under heavy loads. Furthermore, since flexible element 15a, I 5b will stay in its place without rotating, it will not become warm during use and thus it will not cause any heating of the wheel structure. Since flexible element iSa, 15b is of a small size and low mass, the weight of the whole wheel 10 is also low in comparison with state-of-the-art wheels provided with spring suspension. Owing to the location of flexible element I 5a, 1 5b less energy and power are needed to move the conveying wheel 10 in comparison with state-of-the-art wheels provided with spring suspension. Flexible element ISa, I 5b protects the bearing mounting of the wheel and dampens vibration, making the wheel less noisy.

The invention has been described above by way of example and referring to the example shown in the figures of the appended drawing. However, the invention is not restricted solely to the example shown in the figure, but different embodiments of the invention may vary within the scope of the inventive idea defined in the following claims.

Claims

Claims 1. Conveying wheel comprising a wheel body (11), a bearing (13)

mounted in the wheel body, by which bearing the wheel (10) is bearing-mounted on a shaft (17), and a spring suspension (15 a, I 5b) integrated into the wheel structure, characterized in that a flexible element (15a, 15b) bringing about the spring suspension for the wheel is fitted in the radial direction of the wheel inside the bearing (13) in between the wheel body (11) and the shaft (17).

2. Conveying wheel according to claim 1, characterized in that on the wheel shaft (17) a non-rotating internal seal (1 6a, I 6b) is mounted and on the internal race of the wheel bearing (13) a non-rotating external seal (1 4a, 14b) is mounted, and that the flexible element (iSa, 1 5b) achieving the spring suspension for the wheel is mounted in a non-rotating manner in between said internal and external seals (16a, 16b; 14a, l4b).

3. Conveying wheel according to claim 1 or 2, characterized in that the flexible element (15a, 15b) consists of two parts, which parts are fitted on opposite sides of the wheel's mid-line.

4. Conveying wheel according to claim 3, characterized in that the parts (1 5a, I Sb) of the flexible element are located symmetrically in relation to the mid-line of the wheel.

5. Conveying wheel according to claim 3 or 4, characterized in that the flexible element (iSa, l5b) comprises two flexible rings.

6. Conveying wheel according to claim I or 2, characterized in that the flexible element (ISa, I 5b) is formed in one piece.

7. Conveying wheel according to claim 1 or 2, characterized in that the flexible element (15a, 15b) is formed of several separate pieces.

8. Conveying wheel according to any preceding claim, characterized in that in order to make assembling of the wheel easier the internal and external seals (l6a, 16b; 14a, 141,) are made of two parts in such a way that the seal parts can be mounted in their places in the axial direction of the wheel from opposite sides.

9. Conveying wheel according to any preceding claim, characterized in that on the outer surface (12) of the wheel body (11) a coating is mounted to function as the wearing surface.

10. Conveying wheel according to claim 1-8, characterized in that the outer surface (12) of the wheel body (11) functions as the wheel's wearing surface.