GB2159254A

GB2159254A - Foot operated braking mechanisms for trolleys

Info

Publication number: GB2159254A
Application number: GB08509275A
Authority: GB
Inventors: Gerhard Kalteherberg
Original assignee: RODEHAU METALLWARENFABRIK R
Current assignee: RODEHAU METALLWARENFABRIK R
Priority date: 1984-04-16
Filing date: 1985-04-11
Publication date: 1985-11-27
Also published as: FR2562860A1; FR2562860B1; BE902129A; IT1186852B; DE3444799A1; GB2159254B; IT8512465A0; NL8500834A; GB8509275D0

Abstract

Brake operating members 20a, 20b are moved downwards by levers 32 to operate braking mechanisms on a pair of wheels at opposite ends of a trolley. The levers 32 at each end of the trolley are coupled so that movement of one lever 32 also causes the other lever to actuate its associated brake operating member 20a or 20b. This is achieved by wedges 56 and 50 which move longitudinally to wedge one lever downwards, 30b in Fig. 3c, when the other lever is pivoted. In an alternative embodiment, only one lever is provided at one end of the trolley, the brakes at the opposite end being applied by a wedge acting directing on the brake operating member 206. <IMAGE>

Description

SPECIFICATION Locking brake apparatus for running wheels or the like The invention relates to a locking brake for containers capable of running on wheels or the like, more particularly serving trolleys, with securely brakeable running wheels ar ranged on the container base, two each near the ends of said base, their brake elements being engageable pairwise by vertically mova bly guided locking rods extending transversely below the container base, and being movable by downward movement of said bars in opposition to spring force into brake engagement, and for downward movement of such a locking bar there is mounted centrally thereon a pedal or foot lever which projects beyond the container end and whose upper edge which bears against a surface on the container base above the mounting zone is so constructed that the foot lever when depressed moves downwards together with the locking bar, and maintains the downward position until the foot lever is swung back.

A locking brake of this kind is known from German published application 25 08 950. To brake all four running wheels with the known locking brake, a foot lever must be associated with each locking rod, so that foot levers are arranged at both ends of the container, and operation of these in narrow passages or gangways such as occur especially in aircraft, and when there is only one person operating, involves difficulties.

It is also already known (German Utility Model 83 24 703 and German Utility Model 81 23 387) in addition to the foot lever for securing the brake to provide a further foot lever for releasing the brake, arranging said further foot lever on one or both container ends, and to operate therewith separate sliding or rotary wedges for moving the locking rod up and down. When such pairs of levers are provided at both ends, they are coupled together for opposite operation, in pairs, by a linkage extending underneath the container base, so that all four locking brakes can be engaged or released at once from one end of the container. But such locking brakes require a considerable outlay as regards component parts, are bulky and expensive.

The invention has as an object to develop a locking brake of the kind specified initially further in such a way that all four running wheels can be braked locked, and released, with only one foot lever at one container end, and at the same time the outlay on component parts is kept as low as possible.

According to the invention this object is achieved in that the upper edge of the foot lever comprises, above the mounting zone, an asymmetric inflection situated between two straight edge portions, and that at least one elongated element suitable for transmission of traction and pressure forces extends from the foot lever along the container base to behind the other locking rod and comprises there a wedge which on depression of the foot lever, with accompanying traction loading on the elongated eiement, engages the locking rod in that region directly or indirectly, and moves it downwards for braking the running wheels there, and on raising of the foot lever, with accompanying pressure loading on the elongated element, releases the locking rod in that region again.

Thus, thanks to the invention, all four running wheels can be securely braked, and also released again, by operation of a single foot lever, and at the same time the outlay on linkage which obtained hitherto is considerably reduced by the use of a single element starting from the foot lever, owing to its particular property of transmitting both pressure and tractive forces.

According to a first feature in advantageous development of the invention the elongated element is formed of a metal band which is secured at one end to the upper edge of the associated lever and otherwise is guided to be capable of displacement without buckling on the container base. It has surprisingly been found that when suitably guided on the container base a metal band of this kind can transmit fully the pressure force required for releasing the locking brake.

In a further development of the invention a particularly advantageous guiding of the metal band is obtained if the metal band is accommodated in a shallow longitudinal groove on the container base, the said groove being covered by a plate. This has the particular advantage that no projecting parts are present on the container base apart from the running wheels, so that such a container can also be moved over breaks in floor level and the like without a risk of catching.

Finally, the slidable guidance of the metal band can be further improved by coating it with synthetic plastic material such as especially polytetrafluoroethylene to reduce sliding friction.

The invention can be carried into effect with a foot lever arranged at one or both ends of the container. If in the latter case a foot lever is mounted at each of the two locking rods, a particularly advantageous embodiment of the locking brake according to the invention is characterised in that at least one elongated element extends from each of the two foot levers to behind the other foot lever and in that region comprises a wedge which, when one of the two foot levers is depressed, penetrates between the upper edge of the other foot lever and the underside of the container base and moves downwardly the foot lever situated there with the locking bar supporting same, for braking the running wheels in that region.

To obviate asymmetric force transmission this development can be further improved by arranging that two elongated elements extend, with transverse spacing, from one foot lever and at their other ends each comprise a wedge, and that the elongated element starting from the other foot lever extends between these two elements and at its other end comprises a wedge.

With foot levers arranged at both ends in the above-discussed development, therefore, all four running wheels can be braked fast selectively from one or other container end by depressing the foot lever there, and by swinging-back the operated foot lever the wedge situated at the opposite container end is slid back again into the initial position by means of the elongated element, so that the locking rod there also can return again into the released position. But it has been found surprisingly that the release of the locking brake is possible in this case also with the help of the other foot lever by brief depression and lifting again, whereby the wedge there is moved back into the released position and also the wedge at the first foot lever swings the latter back into the released position.

The invention will be described in more detail hereinafter with the use of two preferred examples of embodiment in conjunction with the drawings. In these drawings: Figure 1 is a view from below of a container capable of moving along on wheels or the like in the form of a serving trolley with a first form of embodiment of the locking brake according to the invention, these being operatable by foot levers at both containers ends, the running wheels themselves not being shown, Figure 2 shows a cross-section taken on the line ll-ll in Fig. 1 and showing a running wheel constructed as a swivelling wheel, its swivel bearing and brake likewise being shown in section, Figures 3a-c show a longitudinal section taken on the line Ill-Ill in Fig. 2 in various positions of the locking brake, Figure 4 shows a cross-section on a larger scale taken on the line IV-IV of Fig. 3a, Figure 5 shows a view from below similar to Fig. 1 with a modified form of embodiment of the locking brake which is operatable only from one end of the container by the single foot lever situated there, and Figures 6a and 6b show a longitudinal section similar to Fig. 3a and Fig. 3c in relation to Fig. 5 with the locking brake released and engaged respectively.

In the drawings 10 designates the base plate of an otherwise not further represented dinner wagon or serving trolley, generally referred to simply as a trolley, such as is used in commercial aircraft as a container for dispensing drinks and food to passengers and also subsequently for collecting together the empty packs and dishes and the like.

The relatively narrow serving trolley is supported front and rear by in each case two swivelling wheels arranged with a spacing side by side on the container base, such as is indicated at 12 in Fig. 2. Associated with each swivelling wheel 12 is a brake element which comprises a brake plate 14 adapted to be applied against the running wheel and arranged on the lower end of a pin 16. The pin 16 extends through the hollow swivel shaft 18 of the swivelling wheel 12 and is capable of being displaced downwards into brake engagement in opposition to the force of a spring (not shown).

The brake elements of the two front and the two rear swivelling wheels are actuated in pairs by in each case a locking rod 20a and 20b respectively, the flattened ends of these rods engaging over the brake pins 16 within recesses or indentations 22 on the container base 10. The downwardly cranked central portion of each such locking rod 20a, 20b is guided to be vertically displaceable in the side walls 26, provided with vertical slots 24, of a holder 28 which is securely screwed to the container base.

Secured on the central portion of each brake rod 20a, 20b between the side walls 26 of the holder 28 is a foot lever which at one container end is designated as 30a and at the other container end as 30b. The two foot levers 30a, 30b are of substantially identical construction and their operating ends 32 project from under the container base 10 in such a manner that they can be pressed down or lifted by the person operating the trolley with the front part of the foot.

At its upper edge each foot lever 30a, 30b has an inflection 38 which is situated between two straight edge portions 34, 36 and which, as viewed in a cross-section in relation to the locking rod, is arranged asymmetrically in such a manner that the edge portion 34 adjacent to the operating end 32 has a shorter spacing in the perpendicular sense from the pivoting axis than the other edge portion 36. If a foot lever such as for example the foot lever 30a in Fig. 3a takes up its normal position in which the locking brake is released, the foot lever under the action of the above-mentioned springs at the pins 1 6 bears against a plate 40 on the container base at a location 42 which is offset by the amount E towards the middle of the container relatively to the transverse plane 44 extending vertically through the locking rod 20a. When the foot lever 30a is depressed the location at which the inflection 38 bears on the plate 40 migrates in the opposite direction until the edge portion 36 comes to be situated flat against the plate 40. In this position the point at which the inflection 38 abuts on the plate 40 is already located at a short distance on the other side of the plane 44, whereby a stable state is provided for the foot lever 30a in which the two running wheels arranged at this end of the container are braked with the aid of the downwardly moved locking rod 20a.

As is further shown in Fig. 3 in conjunction with Fig. 1, two metal bands 48 are secured with the use of rivets 46 on the edge portion 34 of the foot lever 30a with spacing from one another in the transverse sense, and extend through between the inflection 38 and the plate 40 along the container base 10 and further also between the inflection 38 and the associated plate 40 on the other foot lever 30b. Secured on the ends of the metal bands 48 in each case is a wedge 50 whose inclined wedge surface extends approximately parallel to the edge portion 34 of the foot lever 30b.

In a similar manner a single metal band 54 is secured by means of rivets 52 to the edge portion 34 of foot lever 30b, and extends in the opposite direction between the metal bands 48 in the first instance between the inflection 38 of the foot lever 30b and the associated plate 40 and then along the underside of the container base 10 to the other foot lever and there through between the inflection 38 and the plate 40 again and comprises at its end a wedge 56 which has the same shape as the wedges 50.

The metal bands 48, 54 are guided in a shallow groove 58 at the underside of the container base 10, this groove being formed in a plate 60. This guiding arrangement makes it possible with the use of the metal bands 48, 54 to transmit even pressure forces without the bands buckling.

As Fig. 3a shows, in the raised release position of the foot levers 30a, 30b, the wedges 50, 56 are situated with their end edges at a distance A from the vertical transverse planes 44 extending through the locking rods 20a, 20b, and the central portions, supporting the foot levers 30a, 30b, of the locking rods 20a, 20b have their axes spaced at a distance B from the underside of the plate 40. in this position the brake plates 14 of all four running wheels are disengaged from the latter, and the entire locking brake is released.

If then, as shown in Fig. 3b, the foot lever 30b is pressed downwards, the right-hand locking rod 20b moves downwards to the spacing D relatively to the underside of the base plate 58, whereby the brakes of the two right-hand running wheels are engaged. At the same time the wedge 56 situated over the left-hand foot lever 30a is drawn by means of the metal band 54 towards the middle of the container, whereby the spacing of its end edge relatively to the transverse plane 44 is shortened to C. Due to this movement the wedge 56 penetrates in between the edge portion 34 of the foot lever 30a and the plate 40 in that region, and shifts the foot lever 30a with the locking rod 20a on which said lever is mounted in a downward direction, so that the brakes of the two running wheels at that end are also engaged. Thus all the brakes are now actuated, and the complete locking brake is engaged.

If then the locking brake is to be released again, this can be done both by lifting the right-hand foot lever 30b and also by brief pressing-down and re-lifting of foot lever 30a.

In the former case, the foot lever 30b can return with the locking rod 20b on which it is mounted into the initial position shown in Fig.

3a, as a result of the lifting of its operating end 32, the wedge 56 also being pressed out of its engagement position with the foot lever 30 by means of the metal band 54, and this foot lever also can return to its initial position shown in Fig. 3a.

If on the other hand the locking brake is to be released by means of the foot lever 30a this lever is at first pressed downwards so that the inflection 38 at its upper edge migrates, as already described, towards the container end and as it does so entrains the wedge 56 (Fig. 3c). The entrainment of the wedge 56 has the result that the foot lever 30b is swung back into the release position by means of the metal band 54 which is subjected to tractive force. Then the foot lever 30a is again lifted into its release position and pushes the wedges 50 by means of the metal bands 48, which are subjected to pressure force, out of their positions of engagement with the foot lever 30b again, so that the foot lever 30b with the associated locking rod 20b can move back again into its initial position (distance B in Fig. 3a).

In the same way, the locking brake can be engaged with the use of the foot lever 30a and then released again selectively by means of foot lever 30a or foot lever 30b.

Providing differing numbers of brake bands acting on the foot levers 30a, 30b and of the wedges secured to said bands is merely intended to establish symmetry relatively to the vertical longitudinal central plane through the container, and to obviate asymmetrical actuations of the two locking rods 20a and 20b with the result of non-uniform braking actions.

To reduce friction when moving within the shallow groove 58 in the plate 60 the metal bands can be coated with a synthetic plastic material such as more particularly polytetrafluoroethylene, as illustrated at 60 in the case of bands 48, 54 in the cross-section on a larger scale shown in Fig. 4.

The locking brake which is shown in Figs.

5, 6a and 6b differs from that shown in Figs.

1-4 essentially in that a foot lever 30 is arranged at only one container end, namely the left-hand end, a metal band 62 leading from said lever to a wedge 64 above the locking rod 20b arranged at the right-hand container end. The wedge 64 is so con structed and arranged that when the foot lever 30 is depressed out of the release position shown in Fig. 6 into the locking position shown in Fig. 6b the said wedge acts directly on the locking rod 20b, and as a result effects the braking-fast of the running wheels arranged at the right-hand container end, whereas the running wheels arranged at the left-hand end of the container are braked-fast by the foot lever 30 by means of the locking rod 20a situated thereat just as in the case of the example of embodiment shown in Figs.

1-4.

To release the locking brake the foot lever 30 is put upwards again by engaging the point of the foot under it, and through the agency of the band 62 presses the wedge 64 out of engagement with the locking rod 20b, so that the running wheels are released again at this end of the container also.

Conveniently, locking brakes of the present invention may have only one foot lever at one or each container end, and comprise only a few components. The use of metal bands as movement-transmitting elements can enable non-encroachment on the ground clearance under a container.

Claims

1. Locking brake apparatus for brake able running wheels or the like, a first pair of said wheels being near a first end of a base that is optionally a container base, a second pair of said wheels being near a second end of said base, said apparatus comprising: first brake elements respectively for said first pair of wheels, said first brake elements being movable for brake engagement, and in opposition to spring force; second brake elements respectively for said second pair of wheels, said second brake elements being movable for brake engagement, and in opposition to spring force; a first locking member extending substantially transversely under said base, said first locking member being guided to be movable substantially vertically, said first locking member being downwardly movable to enable said brake engagement of said first brake elements;; a second locking member extending substantially transversely under said base, said second locking member being guided to be movable substantially vertically, said second locking member being downwardly movable to enable said brake engagement of said second brake elements; a foot lever projecting beyond a corresponding said base end, at least one of said base ends having a respective said foot lever, said foot lever being mounted on a respective said locking member, said foot lever having an upper edge for bearing against a surface provided on said base and above the mounting region of said foot lever, said foot lever when depressed being able to move downwardly with its said locking member so as to enable brake engagement of the corresponding said brake elements until said foot lever is sufficiently moved upwardly, said upper edge comprising above the mounting region of said foot lever an asymmetric inflection between two substantially straight edge portions of said foot lever; and at least one elongate member for transmission of traction and pressure, said elongate member extending from a said foot lever, along said base towards the other base end, to behind the other said locking member and comprising thereat a wedge, which wedge on depression of said foot lever, with traction of said elongate member, engages said other locking member directly or indirectly, and moves said other locking member downwardly so as to enable brake engagement of the corresponding said brake elements, raising of said foot lever, with pressure loading of said elongate member enabling raising of said other locking member so as to enable release of brake engagement of the corresponding said brake elements.

2. Locking brake apparatus as claimed in claim 1, wherein said base is the base of a dinner wagon or serving trolley.

3. Locking brake apparatus as claimed in claim 1 or 2, wherein said first locking member is a bar or rod.

4. Locking brake apparatus as claimed in any one of claims 1 to 3, wherein said second locking member is a bar or rod.

5. Locking brake apparatus as claimed in any one of claims 1 to 4, wherein there is a single said foot lever.

6. Locking brake apparatus as claimed in claim 5, wherein there is a single said elongate member.

7. Locking brake apparatus as claimed in any one of claims 1 to 4, wherein there are first and second said foot levers respectively for said base ends, at least one respective said elongate member extending from each of said foot levers.

8. Locking brake apparatus as claimed in claim 7, wherein there are first, second, and third said elongate members, said first and second elongate members extending from a first said foot lever, with transverse spacing between said first and second elongate members, said third elongate member extending from a second said foot lever and between said first and second elongate members.

9. Locking brake apparatus as claimed in any one of claims 1 to 8, wherein said wedge is such that when a respective said foot lever is depressed, said wedge will penetrate behind the upper edge of the adjacent said foot lever and said base so as to enable said downward motion of the corresponding lock ing member.

10. Locking brake apparatus as claimed in any one of claims 1 to 9, wherein said base comprises a shallow longitudinal groove, optionally in a plate; and at least one said elongate member is within said groove.

11. Locking brake apparatus as claimed in any one of claims 1 to 10, wherein said elongate member is a metal band secured to an upper edge portion of said foot lever.

1 2. Locking brake apparatus as claimed in any one of claims 1 to 11, wherein said elongate member is coated with a synthetic material for reducing sliding friction, said material optionally comprising polytetrafluoroethylene or another suitable plastics material.

1 3. Locking brake apparatus as claimed in any one of claims 1 to 12, wherein said elongate member is displaceable without buckling on said base.

14. Locking apparatus, substantially as hereinbefore described with reference to and as shown in Figs. 1, 2, 3a-c, 4 of the accompanying drawings.

1 5. Locking apparatus, substantially as hereinbefore described with reference to and as shown in Figs. 5, 6a-b of the accompanying drawings.