WO1992012017A1

WO1992012017A1 - Wheel construction

Info

Publication number: WO1992012017A1
Application number: PCT/SE1991/000801
Authority: WO
Inventors: Henrik STÅLHANE; Maria STÅLHANE-BJÖRNBERG
Original assignee: Staalhane Henrik; Staalhane Bjoernberg Maria
Priority date: 1991-01-04
Filing date: 1991-11-26
Publication date: 1992-07-23
Also published as: AU9140491A; SE9100021D0; SE9100021L; SE466538B; EP0564529A1

Abstract

A wheel, primarily intended for food trolleys and the like. The drawing figure is a vertical cross-sectional view through the wheel and an associated trolley, the vertical side face (23) and bottom (24) of which are shown. The wheel has no hub in the traditional sense but is attached to the trolley close to its outer periphery. The wheel comprises an outer annular member (3), an inner annular member (10), rolling elements (6) and a lateral moulding (15). The inner annular member (10) consists of a segment of a circle, i.e. it has an open ring-shape with an engagement rib (14) arranged to be pushed into nesting relationship with the lateral moulding (15). The moulding is provided with screw holes (19) through which the wheel may be secured to the trolley by means of screws (20).

Description

WHEEL CONSTRUCTION

The subject invention concerns a wheel which is intended primarily for food trolleys, grill carts and the like and the outer portion of which comprises an outer annular member having at least one outer race which is open towards the centre and into which rolling elements are filled when the wheel is mounted in position, said elements also cooperating with corresponding inner races which are open outwards and which are formed in the periphery of an inner annnular member.

Today, conventional wheels formed with hubs are used in food trolleys and similar carts. In many cases, it is desirable to use comparatively large wheels in order to be able to push the trolley more easily across thresholds and other obstacles. As a rule, the front and rear wheels are placed in comparatively close relationship to allow easy turning movements.

The wheels may be mounted to the trolley in various ways. A common solution is to use a fixed shaft which is positioned below the trolley bottom face and to mount the wheels on the shaft. In four-wheel trolleys, two shafts are used. In this case, the wheels may be removably attached. One example of application of this construction is for pram wheels.

Another solution is to mount each wheel on iτs individual stub axel which in turn is secured in a fitting element mounted on the trolley. Although this solution provides the designer with more freedom in positioning the wheels on the trolley since it is no longer necessary to use a transverse shaft extending below the bottom face of the trolley, a considerable number of different mounting members are required to suit different types of trolleys. In both cases the disadvantage is that the wheels cover a large area of the lateral faces of the trolley. This disadvantage becomes particularly obvious when the wheels are large and the trolley is equipped with a large number of compartments to which one wishes to have easy access from various directions. In addition, it may be difficult to obtain wheels of suitable size and type for a particular application at a reasonable price, especially in case of small-series production.

The purpose of the subject invention is to remedy the drawbacks outlined in the aforegoing by providing a novel wheel construction which is easy to manufacture and may be mounted in a stable manner to the trolley while at the same time the lateral faces of the trolley are easily accessible. These advantages are particularly significant and obvious in the case of large-diameter wheels.

These purposes are achieved by providing a wheel construction possessing the characteristics defined in the appended claims.

The wheel construction in accordance with the invention thus is essentially characterized in that the wheel has no hub in the ordinary sense of this term. Instead, it has an open centre through which the trolley is accessible. This is achieved as a result of the particular construction of the wheel wherein the outer annular member of the wheel cooperates with an inner annular member with the aid of rolling elements. The inner annular member is not closed but consists of a segment, i.e. an open ring, and it is provided with a profiled engagement member. A lateral moulding may be slid over the engagement member and the lateral moulding is designed to secure the wheel to the trolley. The inner annular member and the lateral moulding both may be manufactured from helically wound extruded bars or sections of appropriate cross-sectional con¬ figuration, for instance of aluminium. In this way, bars or sections of identical cross-sectional configuration may be used for a large range of wheel dimensions and only the outer annular member is individual to each size. In consequence thereof, when a new size or type of wheel is required it is only necessary to select a different diameter for the mandrel about which the bars or sec¬ tions are wound. The reason for this is that the lateral moulding and the inner annular member as a rule have an identical inner diameter, making it possible to use a mandrel common to both. Particularly in the case of small-series manufacture, the manufacturing costs will decrease accordingly. Since the outer and inner annular members of the wheel together have a radial extension exceeding that of the lateral moulding, the latter is hidden from lateral view behind the members, as con¬ sequently also the wheel mounting means securing the wheel to the trolley. In this manner, the side face of the trolley will be accessible via the centre of the wheel while at the same time an interesting visual effect is achieved. The wheel will conceal the trolley only to an extremely small extent. Since the wheel is attached to the trolley by means of the lateral moulding that is positioned close to the outer periphery or rim of the wheel, attachment is established at several places around the periphery, thus creating a stable mounting mode withstanding all kinds of load on the wheel. These advantages from an accessibility and stability point of view are particularly pronounced in the case of large-size wheels. A conventional wheel of this kind covers a large area of the lateral faces of the trolley while at the same time it exposes the associated shaft stub axle to considerable load. A further advantage is that the wheel in accordancae with the invention may be attached in various points along its periphery and not merely, as is the case with conventional wheels, at its hub or centre. This gives the designer considerable freedom in the design of the trolley. Furthermore, it is no longer necessary to provide different stub axles for each type of trolley, which as a rule is the case when conventional wheels are used. 2017 ^l-^im.ⁱo∞-

4 One important aspect of the invention is that the wheel may double as a handle to lift or roll the trolley. There are no spokes or hubs that prevent or interfer with the grip as is the case with conventional wheels. Another very important advantage is that stationary parts and not rotating ones are gripped for this purpose, viz. the inner annular member and the lateral moulding. Examples of applications where this is a particularly vital feature is in wheel-chairs and unloading trolleys for station wagons and small freight trucks.

The wheel may also be formed with a profiled engage¬ ment rib also on its outer face, i.e. the face remote from the vertical side of the trolley. This outer engagement rib may either be formed integrally with the section from the start, for instance by configuring the die casting tool accordingly, or else, the outer engagement rib may be screwed in position later. An outer lateral moulding may then be slid over the outer engagement rib. Accessories in the form of e.g. stands, holders, fittings and/or handles may then be mounted on this outer lateral moulding as the need arises. The lateral moulding may also be formed with recesses for reception therein of an engagement rib on its two axial faces, allowing it be be surrounded by an inner annular member on either side and thus by a wheel on either side. Owing to this arrangement it becomes possible to mount several wheels side by side, i.e. positioned axially next to one another. These wheels may have different outer diameters because of the differences in thickness of the outer annular members. Likewise, it is possible to provide the inner annular members with screw holes, whereby two inner annular members may be screwed together in direct juxtaposed relationship. In this manner, also the outer annular members will be juxtaposed close together. They may be of different external diameter size, the larger wheel being used for instance for displacement of the trolley on the floor while the smaller wheel may cooperate with rails or tracks joined to the floor, allowing the trolley to be rolled in a simple manner along a ramp on rails above the floor level. The wheel has been conceived primarily for use together with mobile interior fittings and similar equipment, mainly for indoor applications and essentially for application in appliances having low-rotational speed and exposed to moderate load.

The wheel construction lends itself to the realiza¬ tion of extremely stable wheels and extremely stable wheel mountings. This is particularly important in the case of mobile interior-fitting units in the form of mobile chopping blocks or work benches that have to respond favourably to working operations involving impacts or the like. In the event of damage to a rolling element any amateur handyman possessing average skills may easily loosen the locking screws of the lateral moulding and, by pushing the moulding aside, make the rolling elements accessible for replacement. In addition, the lateral mouldings are easily replaced or supplemented afterwards in a comparatively simple manner.

Applicants have also found that the supply on the market of suitable wheels, particularly of large-diameter wheels, is very limited. Comparatively cheap types of wheels, often equipped with hub bushings of a plastics material, as a rule have a poor stability and only a limited life. More stable types of wheels, for instance wheel-barrow wheels or bicycle wheels, are a great deal more costly. All types of wheels mentioned require con¬ siderable hub width axially in order to provide a reasonably acceptable degree of stability. The wheel construction in accordance with the invention is not dependent on such axial extension in order to provide high stability. In addition, it allows the wheel to be attached to the trolley in a very simple and elegant way. One embodiment of the invention will be described in closer detail in the following with reference to the accompanying drawings in which identical numeral references have been used in the various figures to indicate corresponding components and wherein.

Fig. 1 is a perspective view of a grill trolley. Fig. 2 is a vertical sectional view through one of the wheels of the trolley and the parts associated with the trolley,

Fig. 3 is a perspective view of the outer annular member of the wheel and a tubular blank used to manufacture the outer annular member, 3a, and likewise shows a cross-sectional view through the annular member, 3b.

Fig. 4 is a perspective view of a helically wound starting blank intended for the inner annular member, 4a. and a cross-section through said inner annular member 4b. Fig. 5 is a perspective view of a helically wound starting blank intended for the lateral moulding, 5a, and a cross section through said moulding, 5b.

Fig. 6 illustrates a method of inserting the rolling elements between the outer and inner annular members, and other features of wheel mounting.

Fig. 7 illustrates another method of inserting the rolling elements between the outer and inner annular members, 7a, and a method of mounting the wheel, 7b. Figs. 8a and 8b illustrate an assembled wheel, additionally provided with a bracket of particular design for mounting the wheel to the bottom of the trolley.

In Fig. 1. reference numeral 2 designates a grill trolley fitted on its top with an upright catalytic LP-gas operated grill. The trolley is fitted with drawers and foldable flaps and could also be fitted with racks for storage of wine bottles. Related types of trolleys are food trolleys, mobile pieces of furniture and mobile workbench carts.

The trolley is provided with "hubless" wheels of a particular configuration, designated by reference 1, which wheels are designed so as to make the trolley sides accessible through the wheel as well as creating an interesting visual effect.

Fig. 2 illustrates the construction of the wheel and the means of mounting thereof to the trolley. The wheel essentially consists of an outer annular member 3, an inner annular member 10 and a number of lateral mouldings 15. Rolling elements 6 are provided by means of which the outer annular member is rotatably mounted for relative movement with respect to the inner annular member, thus allowing absorption also of laterally directed forces. The rolling elements could be in the shape of balls, rollers or needle-shaped elements and they are contained in one or several races, two in number in the drawing figures. Figs. 3 and 4 also show that the outer annular member is formed on its radially inner face with two races 4 and 5 and that the inner annular member is formed with two races 7, 8 on the radially outer peripheral face 9. Fig. 3 also shows that the outer annular member may be manufactured from a tubular blank from which a number of annular members are cut. The material may be aluminium, steel or some other metal, or plastics. In addition, the outer annular member may be cast from metal or plastics or be manufactured by some other well-known manufacturing process, such as pressing. In these applications, non-lubricated bearings may, as a rule, be used including rolling elements made from Delrin plastics, cf. ball bearing pulleys used in sailing-boats. Important characteristics of the invention are that the inner annular member 10 is adapted to cooperate with a lateral moulding 15 and that these two elements are not proper hoops but may be fitted axially one into the other. Figs. 4 and 5 show the cross-sectional configuration of these elements and also how they may be manufactured from helically wound blanks. The manufacture of the helically wound blank preferably is effected by winding a lengths of plastics or metal sections onto a calibrating mandrel. In order to avoid that the elasticity of the material affect the roundness and measurement precision of the blank, heat suitable for the material used, preferably is supplied. The heat treatment may be effected after cold winding or the section may be subjected to this treatment after the winding-on operation. Examples of suitable materials are aluminium or steel, which are extruded to form the sections, or plastics produced by any suitable method.

The helically wound blank is then cut into circular rings, each forming a complete circle. One such ring including an inner annular member 10, may then be mated together with another ring fitted with a lateral moulding 15 in that the two rings are twisted together by intro¬ ducing an engagement rib 14 projecting from one side 13 of the inner annular member into a corresponding groove 16 formed in the lateral moulding 15. In the drawing figures, the engagement rib 14 is dovetail-shaped in such a manner that in a direction radially inwards and outwards it presents two oppositely directed conical faces flaring outwards from the lateral face 13. The groove 16 has a mating configuration so as to securely engage the dovetail-shaped rib 14 and in the two mating components the conical faces extend radially outwards and inwards in a mutually parallel relationship. In order to facilitate the fitting-together of the two components, groove 16 is slightly bigger than the dovetail rib 14.

In order to eliminate inter-part play the lateral moulding 15 is provided with threaded holes 17 into which fastening screws may be threaded so as to exert pressure on the inner annular member 10, forcing the inner annular member and the lateral moulding apart and thus their conical faces into contact with one another. This arrangement is clearly shown in Fig. 2.

From Fig. 2 likewise appears the manner in which the wheel 1 is mounted on the trolley 2. Since the engagement rib 14 extends along the entire peripheral perimeter of the inner anular member 10, one or several sections of the lateral moulding 15 may be applied in such a manner that they cover a smaller portion of the circumference or the entire circumference, various different intermediate positions obviously also being possible.

As appears from Fig. 2, the wheel is attached to the trolley by means of screws 20 which are screwed into threaded holes 19 in the lateral moulding from the side face of the trolley. At the top of the drawing figure is shown a solution according to which two screws are screwed through the vertical trolley side 23 into the holes 19, thus securing the lateral moulding, and consequently the wheel, to the trolley. To ensure stable attachment of the wheel to the trolley at least two screw attachment points are required. The left wheel according to Fig. 1 is screwed onto the vertical trolley face 23 in this manner. Since the wheel itself obscures its means of attachment from view entirely, a visual effect is created when the wheel, seen from the side, appears to be suspended in the air.

The right-hand wheel is attached to the trolley vertically below the latter with the aid of an fastener bracket 21. The latter is in turn screwed onto the trolley bottom 24 by means of screws 22, in this case shown in dash-and-dot lines. In a manner identical to that used for the upper attachment, the lateral moulding 15 is tightened by means of screws 20, shown in dash-and-dot lines, also in the case of the upper attachment. Owing to the provision of the fastener bracket 21 a large portion of the load will be transferred from the wheel directly to the trolley bottom, which may be advantageous, partic- ularly in the case of heavy trolleys. At the same time, the arrangement allows the screws to be screwed in position from the external side face of the trolley.

Considering the above, the assembly of the wheel itself and the insertion of the rolling elements will be described in more detail with reference to Figs. 6-8. In this case. Fig. 6 illustrates the case when the helically wound blank for the inner annular member 10 has not been 2017 P r^VC^mT^m/^tSoE^E.9-,1/00801

10 cut in the radial direction towards the centre but at a definite angle to that direction. Initially, two sections of the lateral moulding 15, viz. one upper moulding section 25 and one lower moulding section 26, are applied on the inner annular member 10. As indicated by the arrows in that figure the sections may be displaced laterally around the inner annular member. Then the inner annular member with the moulding sections applied thereto may be inserted in the outer annular member 3 and with the aid of external means be retained flat inside the latter, where¬ upon the lower free end of the inner annular member is pressed radially inwards in such a manner that a gap forms between the two end edges. Through the gap thus created rolling elements may be inserted into the grooves in the inner and outer annular members. In order to facilitate this operation it is possible to use assembly aids of a kind containing a number of rolling elements and arranged to feed the latter correctly into the gap between the end edges. When the races are filled with rolling element the upper moulding section is displaced towards the left so as to cover the joint, whereupon it is locked in position with the aid of fastening screws 19 which are tightened in the threaded holes 17, cf. Fig. 8. Identically, the lower moulding section is placed in the desired position and fastened by means of screws.

Fig. 7 illustrates a somewhat different method of inserting the rolling elements. In this case the helically shaped inner annular member blank has been cut in such a manner that when the outer annular member is in position, one part is missing. The gap thus left between the two end edges of the inner annular member is used to insert the rolling elements. Once this is done, a supplement part 27 of a particular design is put in position in the place of the missing part. Thereafter, the upper moulding sec- tion 25 is pushed on top of the joint to keep the two ends of the inner annular member and the supplement part 27 in place. Like in the previous alternative, the moulding section 25 is fastened by means of fastening screws 18 which are screwed into the threaded holes 17. This is illustrated in Fig. 8, wherein is also shown the manner in which the lower moulding section 26 is associated with the fastening bracket 21 with the aid of fastening screws 20 screwed into the threaded holes 19.

The rolling elements could also be inserted via the recesses of particular design formed in the lateral faces of the inner annular member 10. These recesses should be sufficiently shallow not to interfere with the regular function of the rolling elements. Likewise it is possible, after insertion of the rolling elements, to close the recesses by external means.

The construction means that, in the area of one or two joints in the inner member 10, the movement of the rolling elements will be interfered with to some extent. For this reason, these joints should normally be directed upwards, when the rolling elements are not exposed to load. Within the scope of the invention many of the com¬ ponents may be configured differently than shown in the drawing figures. For instance, a great many alternative shapes are possible for the engagement rib 14 and the recesses 16. Additionally, they may be reversed, the recess being formed on the inner member 10 and the projecting part being positioned in the lateral mould¬ ing 15. The outer annular member 3 may be formed with different sectional heights, as indicated in phantom lines in Fig. 3. In addition, the wheel may be provided with various kinds of dirt-guard seals as also with seals preventing lubricants from escaping. The lateral moulding 15 may be provided with a seal or else a separate seal be secured with the aid of the engagement rib 14. Also, a separate engagement rib may be formed next to rib 14 as well as separate ribs on the opposite side of the wheel. Likewise, it is possible to produce open inner annular members or sections of varying angular extensions for the lateral moulding in the form of metal or plastic mouldings.

Claims

1. A wheel (1), intended primarily for food trolleys, grill carts (2) and the like and the outer portion of which comprises an outer annular member (3) having at least one outer race (4, 5) which is open towards the wheel centre and into which rolling elements (6) are filled, when the wheel is mounted in position, said elements also cooperating with corresponding inner races (7, 8) which are open outwards and which are formed in the periphery (9) of an inner annular member (10), c h a r a c t e r i z e d in that the inner annular member (10) consists of at least one segment of a circle (11) which is provided on at least one face (12, 13) having an orientation at essentially right angles to the periphery (9), with at least one essentially continuous engagement rib (14) of such a configuration that it may be placed in mating relationship in its longitudinal direc¬ tion with an outer lateral moulding (15), likewise in the shape of a segment of a circle, in such a manner that the engagement rib (14) and the lateral moulding (15) will be essentially securely interconnected in the axial direction of the wheel (1), and in that at least one such segment- shaped lateral moulding part (15) is adapted to mount the wheel (1) to the trolley, cart (2) and the like.

2. A wheel as claimed in claim 1, c h a r a c ¬ t e r i z e d in that the lateral moulding part (15) in the shape of a segment of a circle, which is in nesting relationship with the segment (11) of a circle, is then shifted to a peripheral position wherein it covers the joint between the two end edges of the segment (11) of a circle, as the case may be with a supplementary part (27) positioned intermediate the end edges so as thus to stabilize the two end edges of the segment (11) of a circle with respect to one another.

3. A wheel as claimed in claim 1 or 2, c h a r a c t e r i z e d in that the lateral moulding (15) is provided with drilled and threaded holes (17) passing through the moulding in a direction essentially perpendicularly to the plane of curvature of the moulding so as to ensure that fastening screws (18), when screwed into the holes (17), hit the segment (11) and press the moulding (15) away therefrom to the extent that the engagement rib (14) and the lateral moulding (15) allow, thus fixing the lateral moulding (15) in position relatively to the segment (11) also in the peripheral sense while at the same time establishing connection, without play, between the segment (11) and the lateral moulding (15) and in consequence thereof betweeen the inner annular wheel member (1) and the trolley (2) in the mounted position of the wheel.

4. A wheel as claimed in any one of the preceding claims, c h a r a c t e r i z e d in that the engagement rib (14) is in the shape of an engagement rib (14), said rib projecting from and extending along the lateral face (12, 14) and being thinner at its root close to said lateral face than further away therefrom, and in that the rib cooperates with the lateral moulding (15), the latter being provided with a groove (16) extending in the longitudinal direction of the moulding and having a cross- sectional configuration matching the profile configuration of the engagement rib (14).

5. A wheel as claimed in claim 4, c h a r a c ¬ t e r i z e d in that the engagement rib (14) widens in the direction from its root and further away from said lateral face (12, 13) to essentially the same extent radially outwards as radially inwards, for instance in a T-shape configuration and in a dove-tail configuration.

6. A wheel as claimed in any one of the preceding claims, c h a r a c t e r i z e d in that the inner annular member (10) is in the shape of a segment (11) of a circle and a supplement part (27), the gap between the end 017

15 edges of the segment corresponding to said supplement part (27) being used to fill rolling elements into the races (4, 5, 6, 7) when the wheel is mounted in position.

7. A wheel as claimed in any one of the preceding claims, c h a r a c t e r i z e d in that the lateral moulding (15) is provided with threaded apertures (19) into which fastener screws (20) are screwed in order to secure the wheel for instance to a trolley, the fastener screws (20) extending from the vertical side (23) of the trolley or from the vertical side of a fastener bracket (21) and into the apertures (19).