The present disclosure relates to serving trays, in particular serving trays wherein the tray is carried on one hand of a user, e.g. a waiter or waitress, and food and/or drinks carried on the tray are served from the tray by the user with the other hand.

BACKGROUND

Serving trays of the aforementioned type are ubiquitous, and it is well known that their use critically depends on the ability of the user to balance the tray and in particular in a professional environment, on minimizing user muscle fatigue and spillage. To address this, several approaches have been presented in the art, but none are found satisfactory, e.g. as expounded in US 5,797,495, which itself discloses a serving tray having a substantially planar tray portion with a top surface, bottom surface and periphery, the tray portion being provided with a gripping surface and at least one base ring extending from the bottom side. The gripping surface and base ring are positioned on the tray so that, when one of the gripping surface and the base ring is gripped by the fingertips of the user' s hand, the other can be engaged by the server' s thumb. However, with the serving tray of US 5,797,495 all weight of the tray and goods thereon is carried on the thumb and the size of the tray is limited by the span of the user's hand while further the user' s fingers extend over the tray' s periphery which is unsuitable for high-class environments.

US 6,145,906 discloses a serving tray handling device having a glass or dish supporting surface and an undersurface provided with a finger-gripping projection or core which is surrounded by a recess or groove so that the user's fingers may be inserted into the recess or groove to grip the exterior wall surface of the projection or core. The core may receive a fitted cap of soft material. The core exterior wall surface is tapered inwardly for easy-grip while an opposing recess defining wall may also be inwardly sloped permitting accommodating of finger insertion into the recess or groove. Such serving tray requires gripping a central member (14, 20, 54) with the finger tips in a manner which results in an unnatural posture of the hand with a small finger spread (Fig. 1). Therefore, a user has little stabilisation control over the tray and the finger musculature is heavily burdened.

GB 2 478 299 discloses a serving tray with finger support for stability. A stabilising device for a tray comprises a finger support member, which is connected to the underside of the tray by at least one spacer element. The support and spacer are arranged so that the support member can be moved, preferably by a user's fingers, between a position flush with the underside of the tray and a position spaced from the underside, where a user can locate at least one finger between the tray and the support member. Such tray forces an unnatural and fatiguing flat hand posture with respect to the tray and it prevents rotation of the tray with respect to the carrying hand. The support member further hinders sliding placement of the tray on a surface since it may readily snag behind an edge of the surface. The device may break off of the tray and leave sharp portions .

US 2007/0215512 discloses a serving tray with a fixed and downwardly extending projection permitting removal and entry of an operators hand. Such tray also forces an unnatural and fatiguing flat hand posture with respect to the tray. The device prevents rotation of the tray with respect to the

carrying hand when serving objects from it, preventing

adaptation to an accordingly shifted weight distribution of the (loaded/unloaded) tray.

Reference is further made to the field of disposable plates and the like, wherein e.g. US 3,318,283 discloses a cake circle for supporting and twirling a cake while decorating it, DE 92 01 363 U discloses a foil plate with a structure for fixing the plate on a drinking cup and US 4,746,057 discloses a finger-stabilised eating plate. Such devices are unsuitable as serving trays that should be able to support several beverage and/or food items in/on respective cups, glasses, dishes etc. to be served to consumers .

SUMMARY

Inter alia in view of the above, an improved tray is hereby provided, comprising a top side, a bottom side, and a periphery. The top and bottom sides are generally parallel to each other, the top side being arranged for supporting one or more objects on the tray and the bottom side being arranged for carrying the tray by hand. The tray has a centre of gravity and an axis extending through the centre of gravity substantially perpendicular to the top and bottom sides. The bottom side has a relief providing first and second gripping structures each generally surrounding the axis, the first gripping structure being recessed into the tray and providing a first radially inner gripping surface, in particular for gripping with the thumb of one hand, and the second gripping structure being recessed into the tray and providing a second radially inner gripping surface, in particular for gripping with (the tips of) one or more of the other four fingers (index-, middle-, ring-, and little fingers) of the same hand. In the tray, the first and second gripping structures are arranged such that sections of the first and second inner gripping surfaces are located

diametrically opposite each other at first and second radial distances with respect to the axis, respectively, and such that in plural azimuthal positions around the axis, the ratio of the first and second radial distances of the respective opposite sections are equal.

Thus, in one direction from the axis a first gripping surface section is arranged at a first radial position rl, and opposite from it, relative to the axis, a second gripping surface section is arranged at a second radial distance r2, wherein the ratio R of the first and second radial distances has a particular value (R = rl / r2) . In a further direction from the axis, a further first gripping surface section is arranged at a respective further first radial position rl' and opposite from it, relative to the axis, a further second gripping surface section is arranged at a respective further second radial distance r2', and such that the ratio R' of the further first and second radial distances (R' = rl' / r2' ) has the same value as before: R' = R, even if the first and further first radial distances rl, rl' and the second and further second radial distances r2, r2', respectively, differ.

In this way, the axis of the tray and therefore the centre of gravity of the tray is at the same relative position between the first and second inner gripping surface sections. As a consequence, the tray is always balanced in the same way when gripped at the first and second inner gripping surface sections. Therefore, the tray can be easily and intuitively held and supported reliably by one hand with feeling, engaging and/or gripping the first and second inner gripping surface sections between the thumb and at least some of the other fingers on opposite sides of the axis.

If the ratio R is constant around the axis, the centre of gravity and the balance of the tray is constant around the axis .

If the first and second inner gripping surfaces are substantially continuous around the axis, a reliable grip can be obtained independent of the rotational orientation of the tray around the axis.

If the first and second inner gripping surfaces, or the first and/or second gripping structures as a whole, are

configured as concentric rings, the axis of the tray the effect of the tray, its use and/or benefits may be readily discernible.

In case of concentric circular rings, not only the ratio R but also the radial positions rl, r2, of the first and second gripping surfaces are constant so that an axially

symmetric object is provided of which the gripping size and the balance with respect to the gripping features is identical in any rotational orientation around the axis.

If the top side is generally plane, objects can be placed stably on the tray at will. If the bottom side is, apart from the recessed gripping structures, substantially plane, the tray can be placed stably on a flat table or counter top and/or can be slid from that smoothly and stably, e.g. onto the hand of a user.

If the bottom side comprises one or more further recessed portions, markings in print and/or relief, in

particular being shallow with respect to the depth of the recessed portion(s), e.g. advertisement images, may be provided in the further recessed portions and be shielded against wear when placing and sliding the tray on or against a surface, e.g. a counter. Such recessed portion may conform generally to the shape of the gripping structures around the axis, e.g. be generally circular around the axis. Such further recessed portion (s) also help reducing weight of the tray. A relief may be formed as a marking in itself, e.g. an image and/or a text. A transparent cover over the recessed portion may be provided, further protecting any relief and/or print.

At least one of the first and second gripping structures may be asymmetric and have, in radial cross section, first and/or second inner gripping surfaces with a radially inner slope that is relatively steep and a top surface (bottom surface when seen from the bottom side) having a radially outer outward slope that is relatively small, with respect the radial direction resulting in a small angle relative to axial

direction, e.g. parallel or nearly parallel to the axis and perpendicular to the bottom side. Thus, a reliable and firm inward grip on the tray is possible on the gripping surface (s), and the angle between the top surface of the gripping

structure (s) and the direction of extension of the fingers gripping the respective gripping structure (s) is at a less acute angle than in case of a plane radially extending surface, which reduces the finger-spreading force on the hand encountered with a plane surface.

At least part of the gripping structures, preferably at least the first and/or second inner gripping surfaces, may comprise a rough and/or textured surface, e.g. corrugated, dimpled, knurled etc., and/or may comprise a material that is soft and/or having an elevated friction against human skin, e.g. rubber, silicone rubber, neoprene, or other "non-slip" material. This increases a secure grip on the tray.

If the tray has a circular outer shape, in axial view, the centre of gravity, the axis and the proper balance are readily recognizable, which facilitates stable carrying and balanced loading of the tray. An upstanding rim surrounding the top side prevents slipping and/or leaking from objects and/or liquids on the tray. Al least part of the top side of the tray may further be provided with a non-slip and/or liquid-absorbent surface .

BRIEF DESCRIPTION OF THE DRAWINGS

The above-described aspects will hereafter be more explained with further details and benefits with reference to the drawings showing embodiments of the invention by way of example .

Fig. 1 is a perspective bottom view of a serving tray as provided herein;

Fig. 2 is a bottom view of the tray of Fig. 1;

Fig. 3 is a side view of the tray;

Fig. 4 shows a mid-plane cross section of the tray as indicated in Fig. 2 at VI-VI;

Fig. 5 shows detail V of Fig. 4;

Fig. 6 indicates a method of use of the tray;

Fig. 7 is a perspective bottom view of another embodiment of a serving tray;

Fig. 8 shows, like Fig. 4, a mid-plane cross section of the tray of Fig. 7;

Figs. 9 and 10 show, like Figs. 7-8, a further embodiment of a tray

Figs. 11 and 12 indicate a posture difference between use of a traditional tray and of the presently provided tray;

Fig. 13 is a schematic bottom view of an alternative embodiment of a tray. DETAILED DESCRIPTION OF EMBODIMENTS

It is noted that the drawings are schematic, not necessarily to scale and that details that are not required for understanding the present invention may have been omitted. The terms "upward", "downward", "below", "above", and the like relate to the embodiments as oriented in the drawings, unless otherwise specified. Further, elements that are at least substantially identical or that perform an at least

substantially identical function are denoted by the same numeral.

Figs. 1-4 show a serving tray 1 having a body 2 with a top side 3, a bottom side 5, and an upstanding rim 7 protruding from (the top side 3 of) the body 2 and surrounding the tray 1. The tray 1 has a circular outer shape. In the shown preferred embodiment the tray 1 is generally symmetric about the origin of the circular outer shape and it is so balanced that its centre of gravity is in the centre of the tray 1 and an axis A

extending through the centre of gravity substantially

perpendicular to the top and bottom sides extends through the origin of the circular outer shape.

In the following, all directions are referred to in standard cylindrical coordinates with respect to the axis A.

The tray 1 has a relief comprising two gripping structures 9, 11 formed as recesses 9, 11 in the bottom side 5 into the body 2. Here, the gripping structures 9, 11 are

configured as rings, being symmetrically arranged in concentric circular shape about the axis A and providing a central portion 13 radially inside of the first gripping structures 9, a middle portion 15 between the first and second gripping structures 9, 11 and an outer portion 17 radially outward of the second gripping structure 11. The gripping structures 9, 11 are

arranged for receiving part of the fingertips of a user, typically the thumb in the first gripping structure 9 and at least some other fingertips in the second gripping structure 11, as schematically indicated with tray 1 and hand H in Fig. 6.

Best seen in Figs. 4 and 5, the top side 3 and bottom side 5 are generally plane, apart from the recessed gripping structures 9, 11. The gripping structures 9, 11 each have, in radial cross section, a radially inner first and second gripping surface 9A, 11A, respectively, provided by a wall with a slope into the body 2 that is relatively steep with respect to the radial direction, being generally perpendicular to the bottom side 5, here apart from a small-radius chamfer. The inner gripping surfaces 9A, 11A, are arranged at first and second radial positions rl and r2, respectively. The gripping

structures 9, 11 further each comprise a top surface 9B, 11B which in this embodiment have a radially outward slope relative to the axial direction that is quite small but distinct from being parallel to the bottom side 5. Here, the top surfaces 9B, 11B are also curved. Due to the circular shape of the first and second gripping structures 9, 11 about the axis A, the top surfaces 9B, 11B are generally conical about the axis A with the top angle in upward direction. The top surfaces 9B, 11B are provided with a relief structured to increase friction against human skin, e.g. having an embossed rectangular or honeycomb grid or leather-look print.

In use, the fingers of a user's carrying hand will naturally find the gripping features 9, 11 and assume an optimum position underneath the tray 1 wherein the central portion 13 and the centre of gravity of the tray 1 are arranged over or on the palm of the hand, without the user requiring to test' the balance of the tray and accuracy and security of his/her hold on the tray 1. Thus, the tray 1 can easily be carried in balanced fashion and any unbalance due to uneven loading of the tray 1 can be readily corrected, assisted by the relief of the gripping structure surfaces.

Figs. 7-8 show another embodiment 200 in bottom perspective and mid-plane cross section, respectively. The serving tray 200 is generally similar to the serving tray 1 of Figs. 1-5. As a difference, in the bottom side 205, first and second further recessed portions 219, 221, are provided in the central portion 213 radially inside of the first gripping portion 209 and in the outer portion 217 radially outside of the second gripping portion 211. Here, the first and second further recessed portions 219, 221 extend fully around the axis A and are circular, conforming to the shapes of the first and second gripping structures 209, 211. Thus, the outer portion 217, is substantially formed as the further recess 221 and an outer rim 223, which here extends continuously and circularly around the bottom of the tray 200. Except for the recessed portions and structures 219, 209, 211, 221, the bottom side 205 of the tray 200 is plane.

It is noted that differently shaped further recesses may be provided, e.g. providing a plurality of relatively small- sized recesses in the inner and outer portions 213, 217,

possibly formed as dents, concentric rings, circle segments and/or other shapes like triangles, stars etc.

In the top surface 3 an optional recess 223 is provided which may receive at least part of a lining or cover, e.g.

comprising a liquid absorbent and/or anti-slip-material, which may carry advertisement indicia. The recess 223 may have any suitable size and/or shape.

On the upstanding rim 207, here on the outside thereof, an optional stacking abutment, e.g. a protrusion 225 as shown here, may be provided which facilitates stable stacking of trays and prevents sticking together of stacked wet trays.

Figs. 9-10 show another embodiment of a tray, largely similar to the tray of Figs 7-8 but having different dimensons and a different aspect ratio between (the radii rl, r2 of) the gripping portions 209, 211 and the overall size of the tray.

The recessed nature of the gripping structures 9, 11 in an otherwise plane bottom side facilitates sliding the tray 1 on or off a surface, wherein the user's hand naturally will feel and hold the gripping structures 9, 11, without requiring (time for) testing and checking the appropriate balance of the tray 1. The ergonomic shape reduces strain on and fatigue of the user's hand and reduces chances of tipping the tray and/or spilling carried objects, e.g. drinks. Also, the presently provided tray is thought to improve the user's sense of security and

wellbeing, and thus improves the user's job satisfaction. In a preferred embodiment, the first gripping surface 9A is arranged at a radial position rl of about 4-5 cm,

preferably about 4.3-4.6 cm, e.g. at a radius of about 4.4 cm (= a diameter of ca 8.8 cm), and the second gripping surface is arranged at a radial position r2 of about 6-8 cm, preferably about 6.5-7 cm, e.g. at a radius of about 6.7 cm (= a diameter of ca 13.4 cm). The second gripping portion preferably extends to a radius r3 of about 8-13 cm, more preferably about 9-11 cm, e.g. at a radius of about 10.5 cm (= a diameter of about 21 cm) . It is found that such values tend to fit for most adult hands for providing a reliable grip suitable for serving trays up to about 40 cm diameter, although larger or smaller trays e.g. 20- 50 cm diameter may be provided as well.

In a preferred embodiment, the first and/or second gripping structures are recessed for about 2-5 mm, e.g. 2-4 mm, e.g. about 2.5-3 mm. It is found that such depths, in particular when provided with a rough and/or textured surface, suffice to receive a sufficient portion of a finger tip that a reliable grip can be exerted on the tray. As a result, the tray need not have a particularly thick bottom and therefore may remain quite light weight.

It is noted that the recessed nature of the gripping structure of the presently provided tray reduces the tray' s weight. For example, suitable approximate values for the serving tray shown in Figs. 1-5 are: circular tray of 40.5 cm diameter, base thickness 6 mm, rim height 23 mm, width of first gripping structure 2 cm extending between 45 mm and 65 mm radius, width of second gripping structure 3.5 cm extending between 68 mm and 103 mm radius, depth of first and second gripping structures 2.5 mm, weight 650-800 gram, depending on the material. The

upstanding rim may have another thickness than the base. The strength and weight range of such serving tray are equal to those of customary professional bar and restaurant plastic serving trays of 40.5 cm diameter and 4 mm base thickness. Other typical values are: radial position rl of first gripping surface ca. 44 mm, radial position r2 of second gripping surface ca. 67 mm, depth of first and second gripping structures 3 mm (= height of gripping surfaces) .

In a preferred embodiment, at least one of the first and second radially inner gripping surfaces 9A, 11A, preferably both, has a radially inner slope that extends in an angle α, β with respect to the radial direction about the axis A in a range of 10-60 degrees, in particular 30-50 degrees, i.e. in a range of 80-30 degrees, in particular 60-30 degrees, with respect to the axial direction (see Fig. 8) . The angles α, β need not be egual . It has been found that such angles provide excellent grip and, more importantly, conform to the naturally

stretched/extended position of the fingers of a hand. Thus, overstretching digits as in prior art trays and depicted in Fig. 11 (see the arrows) is prevented and the fingers may assume a straight posture as indicated in Fig. 12. As a consequence, the weight of the tray 1 with any load thereon and associated carrying forces are transferred along the length of (the bones of) the user's fingers to the stronger musculature of the hand palm, the wrist and the arm of the user, instead of having to be supplied (mainly) by the more delicate and generally weaker finger muscles, being overstretched and thus weakened at that.

Fig. 13 shows a serving tray 100 generally similar to that of Figs. 1-10, but here the first and second gripping structures 109, 111 are generally concentric elliptic rings, rather than circular. As shown, as long as the ratio R of the local radial position of the respective first gripping surface rl, rl' and the local radial position of the diametrically opposite respective second gripping surface r2, r2' is generally constant, such tray 100 also provides a centralised grip with constant balance of the tray with respect to the gripping features 109, 111, but the absolute distances between the first and second gripping structures 109, 111, varies with the

rotational orientation of the tray. Thus, the tray 100 may be rotated to fit different hand sizes, while providing constant position of the centre of gravity, so that such rotational size- adjustment can be done without jeopardising the balance and/or stability of the tray and supported goods. In such tray, the outer shape of the tray and the geometry of the first and second gripping structures may correspond, e.g. leading to an

elliptical serving tray. Asymmetric shaped gripping structures, e.g. oval or other may also be provided, in which case the first and second gripping structures should be arranged mirror- inverted about the axis A to maintain a constant ratio R of the radial positions of the respective opposite gripping surface portions .

The present disclosure is not restricted to the above described embodiments which can be varied in a number of ways within the scope of the appended claims. For instance the gripping structures and the tray may have other relative dimensions. The tray need not be round. Further, the gripping structures need not be constant and may be interrupted. A relief of the gripping structure surfaces may comprise concentric circles about the tray's axis A. Further, opposite to the shown embodiments, the first and/or second gripping surface may be at least partly recessed or hollowed inward in radial direction (having a sand-hour-like shape along the axial direction) , providing a waisted central portion and a relatively sharp, somewhat radially outward extending lower, edge to serve as a ledge for increased finger retention. The first and second gripping structures may have different depths, surface

structures and/or surface materials.

Elements and aspects discussed for or in relation with a particular embodiment may be suitably combined with elements and aspects of other embodiments, unless explicitly stated otherwise .