GB1571953A

GB1571953A - Trolley wheels

Info

Publication number: GB1571953A
Application number: GB1840977A
Authority: GB
Original assignee: Ceramiche Ragno SpA
Current assignee: Ceramiche Ragno SpA
Priority date: 1976-06-30
Filing date: 1977-05-03
Publication date: 1980-07-23
Also published as: FR2356526A2; ES228462Y; ES228462U; DE2719173A1; FR2356526B2; IT1069453B

Description

(54) IMPROVEMENTS IN OR RELATING TO TROLLEY WHEELS (71) We, CERAMICHE RAGNO S.p.A., an Italian Body Corporate, of Via Ganaceto, 109, Modena, Italy, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to a wheel for a furnace trolley and is an improvement in or a modification to, the wheel described in our Patent Specification 1,523,445.

Trolley wheels have been proposed in the form of a rim mounted on an axle by means of rolling bearings. These bearings have created problems when the trolley is moved into a furnace, such as occurs in the ceramics industry in which the trolley loaded with tiles traverses tunnel-type firing furnaces. This is because the enormous temperature (many hundreds of degrees) present in the furnace produces irreparable deformation of the bearings and compromises their lubrication. This produces a high resisting moment and abnormal stresses in the bearings, which have had to be frequently replaced at considerable expense. The wheel described in our Patent Specification 1,523,445 overcomes these disadvantages.

According to Patent Specification 1,523,445 there is provided a wheel for a furnace trolley, comprising a hub arranged to be secured to an axle of the trolley and having a peripheral, radially outwardly opening, annular channel of rectangular cross-section, a rim concentrically disposed about the hub and provided with a radially inwardly opening annular channel of rectangular cross-section corresponding to that of the hub, and a plurality of cylindrical rolling bodies each rolling on the bottoms of the channels, said rolling cylindrical bodies comprising a first plurality of rolling bodies which provide a supporting action between the hub and the rim, and a second plurality of rolling bodies constructed of lubricating material and being arranged in alternating relationship with the bodies of the first plurality and in contact therewith so as to lubricate the bodies of the first plurality.

According to the present invention, there is provided a wheel suitable for a furnace trolley, comprising a hub arranged to be secured to an axle of the trolley and having a radially outwardly opening annular groove of substantially arcuate crosssection, a rim concentrically disposed about said hub and having a radially inwardly opening annular groove of arcuate cross-section, and a plurality of loadbearing spherical rolling members engaged in said grooves and arranged to roll in them, said load-bearing spheres alternating with lubricating spheres of solid lubricating material, so that each load-bearing sphere in the wheel is arranged in sliding contact with two lubricating spheres.

An embodiment of the invention will now be described, by way of example only, with reference to the accompanying diagrammatic drawings, in which: Figure 1 is a front view of a furnace trolley wheel taken in the direction of I-I of Figure 2, and Figure 2 is a cross-sectional view taken on line II--II of Figure 1.

With reference to the drawing, a furnace trolley wheel comprises a hub 1 made rotatably rigid by means of a key 2 with the end of an axle 3. The hub 1 is axially locked between a cap 4 fixed by a screw 5 to the end of the axle 3, and a shoulder on the axle.

The hub 1 is provided peripherally with an annular groove 6 of a cross-section substantially in the form of an arc of a circle, and defined on the outer side of the wheel by a ring 7 centred on the hub 1 and fixed on the main body of the hub by throughbolts 8 extending in an axial direction. The groove 6 acts as a guide for a plurality of spheres 9, 10 mutually in sliding contact.

The spheres 9 constitute the load-bearing spheres, while the spheres 10, which alternate with the spheres 9, constitute the lubricating spheres. The spheres 9 are constructed of a steel-based material and the spheres 10 are constructed of a solid lubricating material, for example graphite of a suitable mix, molybdenum bisulphide or the like. The spheres 9, 10 roll peripherally in an annular radially inwardly opening groove 11 of a cross-section in the shape of an arc of a circle defined in the main body of wheel rim 12. The described wheel is completed by two protection plates 14, 15 fixed to opposite faces of the hub 1, and with their edges facing inwards, and engaging in annular grooves 16, 17 provided in the lateral faces of the rim. The plates 14, 15 serve to prevent dust, dirt or the like from penetrating between the spheres 9, 10 and compromising their operation.

The grooves 6, 11 advantageously offer sufficient play to eliminate any axial force on the axle due to deformation of the wheel running rails and to annul any detrimental effect deriving from thermal expansion.

The lubrication spheres disposed between the load-bearing spheres ensure a reduction in resistance as, because of the special characteristics of the material used, lubrication is provided even at high temperatures.

In the wheel described, the surfaces of the rim and hub on which the spheres roll can be located at an increased distance from the axis of the wheel without changing the overall size of the wheel. This makes the operation of the wheel less sensitive to the effect of imperfections in the construction and assembly of the wheel or the presence of impurities on the rolling surfaces.

Because the load-bearing function is entrusted exclusively to the set of spheres 9 constructed of steel-based material, the spacing and lubricating spheres 10 may be of a smaller diameter than the diameter of the corresponding load-bearing spheres.

Furthermore, the disadvantages which tend to arise in the case of conventional furnace trolley wheels due to excessive axial temperature, such as the need for continuous and periodical lubrication, and the accumulation of carbon deposits along the bearing races leading to seizure are obviated.

The wheel described herein is of relatively simple construction, and is economical to manufacture.

WHAT WE CLAIM IS: 1. A wheel suitable for a furnace trolley, comprising a hub arranged to be secured to an axle of the trolley and having a radially outwardly opening annular groove of substantially arcuate crosssection, a rim concentrically disposed about said hub and having a radially inwardly opening annular groove of arcuate cross-section, and a plurality of loadbearing spherical rolling members engaged in said grooves and arranged to roll in them, said load-bearing spheres alternating with lubricating spheres of solid lubricating material, so that each load-bearing sphere in the wheel is arranged in sliding contact with two lubricating spheres.

2. A wheel as claimed in claim 1, wherein the lubricating material comprises graphite.

3. A wheel as claimed in claim 1, wherein the lubricating material comprises molybdenum bisulphide.

4. A wheel as claimed in claim 1 or 2, wherein one side of one of said grooves is defined by a ring fixed to the main body of the surrounding rim or hub.

5. A wheel as claimed in any preceding claim, wherein the load-bearing spheres and the lubricating spheres are of substantially the same diameter.

6. A wheel as claimed in any one of claims 1 to 4, wherein the lubricating spheres are of smaller diameter than the load-bearing spheres.

7. A wheel substantially as hereinbefore described with reference to the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. rotatably rigid by means of a key 2 with the end of an axle 3. The hub 1 is axially locked between a cap 4 fixed by a screw 5 to the end of the axle 3, and a shoulder on the axle. The hub 1 is provided peripherally with an annular groove 6 of a cross-section substantially in the form of an arc of a circle, and defined on the outer side of the wheel by a ring 7 centred on the hub 1 and fixed on the main body of the hub by throughbolts 8 extending in an axial direction. The groove 6 acts as a guide for a plurality of spheres 9, 10 mutually in sliding contact. The spheres 9 constitute the load-bearing spheres, while the spheres 10, which alternate with the spheres 9, constitute the lubricating spheres. The spheres 9 are constructed of a steel-based material and the spheres 10 are constructed of a solid lubricating material, for example graphite of a suitable mix, molybdenum bisulphide or the like. The spheres 9, 10 roll peripherally in an annular radially inwardly opening groove 11 of a cross-section in the shape of an arc of a circle defined in the main body of wheel rim 12. The described wheel is completed by two protection plates 14, 15 fixed to opposite faces of the hub 1, and with their edges facing inwards, and engaging in annular grooves 16, 17 provided in the lateral faces of the rim. The plates 14, 15 serve to prevent dust, dirt or the like from penetrating between the spheres 9, 10 and compromising their operation. The grooves 6, 11 advantageously offer sufficient play to eliminate any axial force on the axle due to deformation of the wheel running rails and to annul any detrimental effect deriving from thermal expansion. The lubrication spheres disposed between the load-bearing spheres ensure a reduction in resistance as, because of the special characteristics of the material used, lubrication is provided even at high temperatures. In the wheel described, the surfaces of the rim and hub on which the spheres roll can be located at an increased distance from the axis of the wheel without changing the overall size of the wheel. This makes the operation of the wheel less sensitive to the effect of imperfections in the construction and assembly of the wheel or the presence of impurities on the rolling surfaces. Because the load-bearing function is entrusted exclusively to the set of spheres 9 constructed of steel-based material, the spacing and lubricating spheres 10 may be of a smaller diameter than the diameter of the corresponding load-bearing spheres. Furthermore, the disadvantages which tend to arise in the case of conventional furnace trolley wheels due to excessive axial temperature, such as the need for continuous and periodical lubrication, and the accumulation of carbon deposits along the bearing races leading to seizure are obviated. The wheel described herein is of relatively simple construction, and is economical to manufacture. WHAT WE CLAIM IS:

1. A wheel suitable for a furnace trolley, comprising a hub arranged to be secured to an axle of the trolley and having a radially outwardly opening annular groove of substantially arcuate crosssection, a rim concentrically disposed about said hub and having a radially inwardly opening annular groove of arcuate cross-section, and a plurality of loadbearing spherical rolling members engaged in said grooves and arranged to roll in them, said load-bearing spheres alternating with lubricating spheres of solid lubricating material, so that each load-bearing sphere in the wheel is arranged in sliding contact with two lubricating spheres.