GB2180278A - Elastically compressible suspended beam, bending over the length - Google Patents

Abstract

A suspended beam comprising a basic beam (1) on which a footboard (8) is supported via an elastically compressible spring means (9) and vertically guided along the basic beam by means of narrow leg strip (7). In this arrangement it is desirable that the elastic characteristics of the suspended beam should be more uniform over the length. This is achieved in the invention due to the fact that the narrow leg strip (7), which is rectilinear in the vertical direction, engages in a groove (6) of the basic beam (1) and comprises longitudinally spaced gap-forming cut-outs (16) extending upwards from its lower free edge. The tooth-like subdivided region of the leg strip is held together in the groove and renders the leg strip and the footboard elastically bendable over the length thereof. <IMAGE>

Description

SPECIFiCATION Suspended beam The invention relates to a suspended beam/balance beam, comprising a basic beam on which a footboard issupported by means of an elastically compressible spring arrangement and vertically guided along the basic beam by means of a narrow leg strip.

In a known suspended beam ofthis kind (DE-OS 33 22245) the footboa rd is provided with two downwardlyextending outwardly domed leg strips which are guided via spacerelements along thetwo longitudinal sides of the basic beam. Due to the provision ofthe two leg strips and the two spacer elements the footboard has bending rigidity over its length which affects the elasticcharacterisitics ofthe suspended beam along its length. For example, the footboard will present a different yielding behaviour under load applied thereto near one of its ends than under load applied in the middle ofthesuspended beam.

It istherefore an aim ofthe present invention to create a suspended beam ofthe kind specified which has more uniformly equalised elastic characteristics over its Fength. Solving this problem, the suspended beam according to the invention is characterized in that the narrow leg strip is rectilinea r in the vertical direction and extends into agrooveofthe basic beam and is further provided with longitudinally spaced gap-forming cut-outs or recesses extending upwards from its lowerfree edge.

In other words, the leg strip isoftooth-like configuration in the lower strip region and thus becomes bendable in the vertical direction over its length. The toothed strip region is retained in the groove and because ofthis the groove provides firm guidance and supportforthe footboard despite its tooth-like sub-division. The elastic properties ofthe suspended beam along its length are made more uniform and the footboard becomes elastically bendable. In the suspended beam according to the invention the masses which must share in movement when the footboard is in use or moved, are extremely small, especially when only one single leg strip is provided. There are no mass-representing spacer elements.Bythe distribution of the cut-outs over the length of the leg strip it is possible to influence the elastic bending ability of the footboard over its length.

It is conceivable also with groove-engagement of the vertically straight leg strip to provide two relatively spaced leg strips each being guided in one groove.

However, it is particularly convenient and advan tageous to provide only one central leg strip on the footboard, with elastic blocks or spring packets supporting it at both longitudinal edges. Such a single leg strip-guide groove arrangement is enough to mount the footboard in tilt-proof manner and secure it against any displacement in a lateral direction relative to its length.

It is also particularly convenient and advantageous ifthe longitudinal sides ofthe suspended beam are outwardly domed across its height and each domed longitudinal side consists of the basic beam and an elastically compressible spring strip arranged between the basic beam and the footboard. The construction ofthis suspended beam is thus simplified.

ltisfurtherconvenientand advantageous ifthe spring means along the two longitudinal edges of the footboard in each case comprise an outwardly directed longitudinally uninterrupted through-extending elastically compressible spring strip and adjoining the same on the inwardly directed side a further elastically compressible spring block structure. The outer spring strip is primarily designed to form the exterior contour of the suspended beam and the inner spring block structure is primarily designed to provide the desired spring characteristics. Separate parts are provided forthese two functions.

The extent or reach ofthe cut-outs over the height of the leg strip will be selected in accordance with the desired bendability ofthefootboard. However, it is particularly convenient and advantageous if the cutouts extend upwards beyond the upper edge of the groove in the relaxed state ofthe spring system. In such arrangements the influence of the leg strip region which ensures guidance and support in the groove in respect ofthe bending ability of the footboard is minimized.

The configuration ofthe incisions or cuts may be adapted to local con conditions. It is particularly conve- nient and advantageous if the cut-outs take the form of slit-like incisions. Such slit-like incisions can be easily produced and afford the most favourable manner of assuring the desired ben da bi I ity fo r th e footboard.

It is also particularly convenient and advantageous if the footboard complete with the leg strip is made integrally from an inherently hard plastics material.

The footboard together with the leg strip region which is provided with the incisions is elastically bendable but the plastics material is not, like foamed material, elastically compressible. The production of a plastics component consisting offootboard and leg strip is relatively simple.

It is also particularly convenient and advantageous ifthefootboard complete with leg strip is made up along its length by two or more sections and in each case two adjoining sections interengage positively by groove and tongue engagement in the region ofthe leg strip. The joint between two adjacent sections realises similar conditions to those produced by a cut-out in the leg strip. The required bending rigidity is established by the groove and tongue-interengagement.

Finally, it is also particularlyconvenientandadvan- tageous ifthe leg strip over its length is provided with relatively longitudinally spaced vertical elongated slots in each ofwhich is engaged a horizontal bolt fixed in the basic beam. These bolts do not detract from the elastic characteristics ofthefootboard but they prevent the footboard from lifting upwards off the beam. When no load is applied to thefootboard the bolts abut the lower ends ofthe elongated slots whilst the spring system may be slightly in pre-applied tension.

The invention will now be described, byway of example, with reference to the accompanying drawings, in which: Figure lisa perspective view with open section of a suspended beam of the invention, Figure 2 is a section ofthe beam of Figure 1 on a larger scale, and Figure 3 is a fragmentary side view of a footboard with leg strip ofthe suspended beam of Figure 1, drawn to the same scale as Figure 1.

The suspended beam according to the drawings comprises a basic beam 1 which is an aluminium alloy-section. At its underside the basic beam 1 has a channel 2forfixing itto a base frame. Along each of its two longitudinal sides it has a wall 3 which is outwardly domed over its height, and at the top, adjacent said walls, are provided cover strips 4 and two groove walls 5, leading in each casefromthe inner edge of a cover strip downwa rdly towards the bottom ofthe beam 1. These two groove walls define between them a verticallystraight groove 6 extending over the length of the suspended beam, the width ofthe groove being substantially less than its height or depth.In this groove 6 is vertically slidably guided a leg strip 7, which, together with a horizontal footbaord 8, forms an integral T-structure made from a compact material.

The vertical extent of the portion ofthe leg strip which engages in the groove 6 is greaterthan the veritcal extent of that portion ofthe strip which projects upwardly out ofthe groove, and the width ofthe footboard is less than the externally measured total width ofthe cover strips 4 ofthe basic beam. On both sides of the leg strip 7 spring means 9 are provided between thefootboard 8 and the topside ofthe basic beam 1 over the length ofthe beam.An inverted channel-shaped outer cover 10, which is secured at its ends to the basic beam, extends from one wall 3 ofthe basic beam 1, over the one side of the spring means 9, over and across the topside offootboard 8, over the other side ofthe spring means 9to the otherwall 3 of the basic beam.

As shown also in Figure 2, the spring means 9 on both sides ofthe leg strip are each oftwo-part construction, in as much as on the outwardly directed side is provided an elastic strip 11, which consists of a foam material, and which is covered by the outer cover 1 the strip 11 extending continuously over the length ofthe beam. The wall 3 of the basic beam 1 and the elastic strip 11 togetherform the vertically outwardly domed longitudinal side 12 ofthe suspended beam. Next to the elastic strip 11 in the inward direction is a spring-block structure 13 which representsthe actual spring device forthefootboard 8 and is distributed or extends overthe length ofthe suspended beam.The spring block structure 13 is, for example, composed ofindividual elements arranged in a rowor itis in one piece overthe length.

A pin or bolt 14 extends from one wall 3 to the other and passesthrough both groovewalls5aswell as through the leg strip 7, namely in the region of one of a number of relatively spaced vertical elongated slots 15 therein.Asshown in Figure 1,several bolts 14 are provided along the length. According to Figure 3 the leg strip 7 is provided with cut-outs 16 in the shape of incisions. The relative association ofthe incisions 16 and groove 6 will be noted by a comparison of Figures 1 and 3 which are drawn to the same scale. According to Figure 3 the footboa rd-leg strip assembly is subdivided along its length and the sections are buttjointed at 17. At the joint 17 the sections interengage by means of a projecting tongue 18 and groove 19.

The spring means 9 is maintained intension by means ofthe bolts 14. This pre-applied tension favours the function ofthe spring means which reacts faster and stronger. This is particularly important if the footboard 10 is required to react only in localised fashion.

Claims (11)

1. A suspended beam comprising a basic beam and, supported thereon via elastically compressible spring means, a footboard which is vertically guided along the basic beam by means of a narrow leg strip, characterised in that narrow leg strip of rectilinear configuration in the vertical direction engages in a groove ofthe basic beam and is provided with longitudinally spaced-gap-forming cut-outs extending from its free lower edge in the upward direction.

2. Asuspended beam as claimed in claim 1, characterised in thatthe footboard is provided with only one centrally arranged leg strip, whilst being supported at both longitudinal edges by spring block assemblies.

3. Asuspended beam as claimed in claim 1 or claim 2, in which the longitudinal beam sides are outwardly domed across the height of the beam, characterised in that each domed longitudinal side is formed bythe basic beam and an elasticallycom pressiblespring strip arranged between the basic beam and thefootboard.

4. A suspended beam as claimed in any one of claims 1 to 3, characterised in that the spring means along the two longitudinal edges ofthefootboard in each case comprise on the outwardly directed side an elastically compressible spring strip extending continuously over the beam length, and adjoining the same in the inward direction, a further elastically compressible spring-block assembly.

5. Asuspended beam as claimed in any one ofthe preceding claims, characterised in that in the relaxed state ofthe spring means, the cut-outs extend upwards beyond the upperterminal edge ofthe groove.

6. Asuspended beam as claimed in any one ofthe preceding claims, characterised in that the cut-outs are slit-like incisions.

7. A suspended beam as claimed in any one ofthe preceding claims, characterised in that the footboard together with the leg strip is an integral piece made from an inherently hard synthetic material.

8. Asuspended beam as claimed in any one of the preceding claims, characterised in th at the footboard including leg strip is lengthwise assembled from two or more sections, and every two relatively adjacent sections interengage by a tongue and groove connec tionintheleg strip.

9. A suspended beam as claimed in anyone ofthe preceding claims, characterised in that the leg strip is provided along its length with relatively spaced vertical elongated slots, each being penetrated by a horizontal bolt anchored in the basic beam.

10. A suspended beam as claimed in any one of the preceding claims, characterised in thatthe spacing means are maintained in pre-applied tension.

11. A suspended beam substantially as hereinbefore descri bed with reference to and as shown in the accompanying drawings.