US3889779A

US3889779A - Length adjustable plank

Info

Publication number: US3889779A
Application number: US514769A
Authority: US
Inventors: Walter Kummerlin
Original assignee: Individual
Current assignee: Individual
Priority date: 1973-10-23
Filing date: 1974-10-15
Publication date: 1975-06-17
Anticipated expiration: 1992-06-17

Abstract

A length adjustable plank comprising at least two parts longitudinally adjustable relative to each other, each including two parallel longitudinal beams constituting profile rods, and forming a longitudinal guide, and transverse beams forming a standing surface covering the longitudinal beams and connecting the latter to each other. The longitudinal beams of one part are guided between the longitudinal beams of the other part, and the length of the transverse beams on top of the outer lying longitudinal beams equals the width of the plank, whereas those on top of the inner lying longitudinal beams are somewhat smaller in length than the open spacing of the outer lying longitudinal beams. A fastening device secures the inner lying longitudinal beams in the use condition such that the respective transverse beams of both parts over the inner and outer lying longitudinal beams, respectively, mesh with each other in the manner that the upper surfaces of the transverse beams lie substantially in the same plane.

Description

United States Patent [191 Kiimmerlin l l LENGTH ADJUSTABLE PLANK [76] lnventor: Walter Kiimmerlin. ln Den Fressackern 6 7120 Bissingen. Enz. Germany 22 Filed: Oct. 15. I974 211 Appl. No; 514.769

1 1 June 17, 1975 Primary Etmnincr-Reinaldo P. Machado Attorney Agent. or Firm-Martin Allen Farher [57] ABSTRACT A length adjustable plank comprising at least two parts longitudinally adjustable relative to each other. each including two'parallel longitudinal beams constituting profile rods. and forming a longitudinal guide, and transverse beams forming a standing surface covering the longitudinal beams and connecting the latter to each other The longitudinal beams of one part are guided between the longitudinal beams of the other part. and the length of the transverse beams on top of the outer lying longitudinal beams equals the width of the plank, whereas those on top of the inner lying longitudinal beams are somewhat smaller in length than the open spacing of the outer lying longitudinal beams. A fastening device secures the inner lying longitudinal beams in the use condition such that the respective transverse beams of both parts over the inner and outer lying longitudinal beams, respectively mesh with each other in the manner that the upper surfaces of the transverse beams lie substantially in the same plane.

16 Claims. 6 Drawing Figures LENGTH ADJUSTABLE PLANK The invention relates to a length adjustable plank comprising at least two parts which are adjustable relative to each other in the direction of their length, each of which comprises longitudinal beams which are arranged parallel and Spaced from each other, as well as transverse beams.

With the known length adjustable planks. which preferably are used for working platforms. or scaffolds. and frameworks or structures. each part comprises several wood strips lying parallel to one another and extending over the entire length ofthe part, the distance of which from each other is somewhat larger than the width of the wood strips measured in the transverse direction. In the intermediate spaces between the wood strips of the one part. lies the wood strips of the other part. and at their ends these longitudinal strips are connected to each other by transverse strips. It is disadvantageous with these known planks, that first of all. if the user stands on the edge zone. only one or two of the longitudinal strips are loaded Because of its relatively long length, the strips tend then to spread apart. leaving large openings therebetween, or to tip. It can indeed come to the breaking of the strips, since on a weight basis each individual strip can not be given such a large carrying capacity that it alone has the ability to carry the load. Furthermore it is disadvantageous that on account of the woodwork, ie, the nature of wood to absorb water and as a result to swell. a relatively large play must be provided between the strips. which likewise considerably influences the stability of the plank. Finally it is still of disadvantage that the transverse strips, which connect the longitudinal strips to one another, necessarily project over the upper side of the longitudinal strips which forms the standing surface. and in this manner form raised portions, which present a danger of stumbling.

It is an object ofthe invention to produce a plank that has an improved load supporting capacity.

It is another object of the invention to provide a plank having an increased safety by avoiding ofinsufficiently stable parts of the plank and parts projecting over the standing surface.

It is still another object of the invention to provide a plank achieving a minimum weight with a predetermined load supporting capacity, as well as a ready, comfortable ease of handling. especially with the length adjustment.

It is yet another object of the present invention to develop the transverse beams in a manner which permits a connection with the longitudinal beams with the lowest possible expense.

It is yet still another object of the invention to provide a length adjustable plank comprising at least two parts adjustable relative to each other in their longitudinal direction, which each comprises longitudinal beams arranged parallel and spaced from each other as well as transverse beams, the longitudinal beams of the two parts forming the longitudinal guide, characterized in the manner that each part comprises two longitudinal beams made of profile rods, which by the transverse beams are covered and connected to each other, the transverse beams forming the standing surface for the user, whereby the longitudinal beams of the one part are guided between the longitudinal beams of the other part and the length of the transverse beams on top of the outer lying longitudinal beams is equal to the width of the plank. and the length of the transverse beams on top of the inner lying longitudinal beams to the contrary being somewhat smaller than the open spacing of the outer lying longitudinal beams. and that further a securing device is provided by means of which the inner lying longitudinal beams are so fixed in the use condition of the plank such that the transverse beams over the inner lying longitudinal beams and the trans verse beams over the outer lying longitudinal beams so mesh in each other such that the upper surfaces of the transverse beams lie substantially in the same plane.

It is yet still another object of the invention to provide a length adjustable plank in accordance with the above-mentioned objectives, respectively. further wherein the transverse beams are spaced from each other by a distance corresponding substantially to their width.

It is yet still another object of the invention to pro vide a length adjustable plank in accordance with the above-mentioned objectives. respectively. further wherein the transverse beams constitute light metal profile members.

It is yet still another object of the invention to pro vide a length adjustable plank in accordance with the above-mentioned objectives. respectively, further wherein the height of the inner disposed longitudinal beams is smaller than the height of the outer disposed longitudinal beams at least by the height of the transverse beams over the inner lying longitudinal beams.

It is yet still another object of the invention to provide a length adjustable plank in accordance with the above-mentioned objectives, respectively. further wherein the transverse beams on top of the inner lying longitudinal beams constitute raised sections of at least one corrugated type shaped plate.

It is yet still another object of the invention to provide a length adjustable plank in accordance with the above-mentioned objectives, respectively, further wherein the transverse beams on top of the outer lying longitudinal beams constitute raised sections of at least one corrugated type shaped plate, the profile of which is complementary to the profile ofthe plate forming the transverse beams on top of the inner lying longitudinal beams.

It is yet still another object of the invention to provide a length adjustable plank in accordance with the above-mentioned objectives, respectively, further wherein the profiles of the plates are trapezoidal in cross-section.

It is yet still another object of the invention to provide a length adjustable plank in accordance with the above-mentioned objectives, respectively, further wherein a hand rail is articulated to each of the outer disposed longitudinal beams, respectively.

With the above and other objects and advantages in view, the invention will become better understood in connection with the following detailed description of various embodiment examples by reference to the accompanying drawings, of which:

FIG. I is a perspective view ofa first embodiment example of a length adjustable plank in accordance with the invention;

FIG. 2 is a longitudinal section taken along the lines II-II of FIG. I and broken away in part;

FIG. 3 is a broken away section taken along the lines III-III of FIG. 2, whereby in the left part of FIG. 3 the use position illustrated in FIG. 2 is shown. and in the right part the adjustment position of the two parts is illustrated;

FIG. 4 is a schematic front view of a second embodiment of a longitudinally adjustable plank;

FIG. 5 is a perspective view of a third embodiment of a length adjustable plank; and

FIG. 6 is a broken away longitudinal section taken along the lines Vl\/l of FIG. 5.

Referring now to the drawings. and more particularly to FIGS. 1 and Z, a length adjustable plank has a first part designated as a unit by the reference number I and a second part designated as a unit by the reference number 2, which parts each comprise two

longitudinal beams

3 and 4, and 5 and 6, respectively. constituting profile rods. which lie parallel to one another and spaced from one another. as well as

crossbars

7 and 8, respectively. constituting transverse beams. extending perpendicularly to the longitudinal beams and engagingly supported on the latter. which crossbars are rigidly connected with the longitudinal beams. The

crossbars

7 and 8 all have the same width and also the same spacing from adjacent crossbars of the same part. This spacing is. as particularly shown in FIG. 2, slightly greater than the width of the

crossbars

7 and 8.

1n the embodiment example. not only are the

longitudinal beams

3, 4, 5 and 6 made of aluminum. but also the

crossbars

7 and 8. The latter yet. for example. can also be made of wood.

The cross sectional profile of the

crossbars

7 and 8 is illustrated in FIG. 2 as a rectangularly shaped solid profile. Such a solid profile may be used fundamentally not only with crossbars made of wood. but also with crossbars made of light alloy or metal, herein referred to as light metal. Suitable with crossbars made of light metal. is however. a flat section reinforced under circumstances by corrugations. which flat section can be equipped with stamped out portions. or holes. the edges of which point upwardly and lie in the plane forming the standing surface. so that the crossbars are trip-proof.

The two longitudinal beams 3 and 4 of the first part have a larger spacing from each other than the two

longitudinal beams

5 and 6 of the second part and differ also with respect to their profiles. as shown in FIG. 3. The length of the rails 3 and 4 of the first part is however equal to the length of the

rails

5 and 6 of the second part.

The profile of the longitudinal beams 3 and 4 comprises. as shown in FIG. 3, a transverse section 10 forming the support for the crossbars 7, a middle section 11 disposed perpendicularly relative thereto and forming therewith a T-profile. well as a bottom tranverse section 12 joining perpendicularly on the bottom edge of the middle section 11 and pointing towards the oppo site longitudinal beam. To the contrary the

longitudinal beams

5 and 6 relate to an edgewise oriented rectangu lar tube. The width of this tube measured in the longitudinal direction of the crossbars S is somewhat smaller than the length of the transverse section 12 measured in the same direction. Further. the height of the tube measured crosswise thereto. is, at least by the thickness of the crossbars 8 smaller than the distance of the bottom transverse section 12 from the upper transverse section 10 of the longitudinal beams 3 and 4, as shown in the right-hand part of FIG. 3. The crossbars 8 differ from the crossbars 7 only with respect to their thickness. which is larger than the thickness ofthc crossbars 7 by the thickness of the transverse section It), as well as with respect to their length. as FIG. 3 shows. which length of the crossbars 8 is somewhat smaller than the spacing ofthe longitudinal edges which face each other of the transverse sections 10 of the longitudinal beams 3 and 4, respectively.

In order to increase the stability. transverse struts 13 are positioned on the surface of the two transverse sections 12, the transverse struts 13 extending parallel to the crossbars 7 and disposed spaced from each other. and rigidly connected with the longitudinal beams 3 and 4. In the embodiment example, the transverse struts 13 are flat rails with a relatively small cross section. since they are stressed practically only by tensile forces. Should however the plank be used also as a ladder for leaning against a wall. or the like, then the transverse struts 13 must be dimensioned as the rungs of a ladder. In a suitable way in this case. also. the spacing of the transverse struts I3 is selected equal to the spacing of the ladder rungs. Correspondingly. this holds for the transverse struts 14 which extend parallel to the crossbars 8 from the longitudinal beam 5 to the longitudinal beam 6, and which struts are rigidly connected with the beams on the surfaces facing each other. at the lower third /3) of the longitudinal beams. By these transverse struts 14, as well as the crossbars 8. the two

longitudinal beams

5 and 6 are held at such a distance from each other that between them and the adjacent longitudinal beams 3 and 4, respectively, there is presem a little play. when the second part 2 is pushed in completely or partially between the longitudinal beams 3 and 4 of the first part I. The play is. in a suitable manner. selected such that the longitudinal beams 3 and 4 form an easy access slide guide for the second part 2, yet excluding any relative tilting or misalignment of the

parts

1 and 2.

The bottom transverse sections 12 are equipped with two threaded bores which are arranged spaced from each other in the range of the end portion of both longitudinal beams 3 and 4, in each of which bores a threaded spindle 15 is guided. As FIG. 2 shows, in the embodiment example the two threaded bores are provided at those positions at which the first and second transverse struts 13 lie. Of course, in case of necessity, one can provide a threaded bushing instead of a threaded bore. and insert the latter in a smooth bore of the bottom transverse section. The threaded spindle 15. which is provided with a handle 16 on its lower end. and with a pressure plate 17 which is rotatable about the spindle axle on its upper end. the latter pointing to a crossbar 8, is aligned on the center of the longitudinal beams S or 6, which beams are arranged thereover'. and the threaded spindle l5 has such a length that the longitudinal beams can be held on the one hand in position on the upper transverse section 10 (compare the left part of FIG. 3), and on the other hand can be lowered so far to the bottom end section 12 such that the upper side of the crossbars 8 lies lower than the lower side of the crossbars 7 (compare the right side of FIG. 3). The threaded spindle 15, the handle 16 and the pressure plate 17 constitute a clamping device.

For transportation. in a suitable manner the second part 2 is pushed completely into the first part 1 and in this position is secured in the manner that with the aid of the screw spindle 15 one holds the

longitudinal beams

5 and 6 fixed in position on the transverse section 10. Since the screw spindles are formed self locking. and the Crossbars prevent a longitudinai displacement, this position of the second part 2 can not be changed inadvertently For the adjustment of a predetermined length of the plank, the screw spindles 15. forming each a manually actuatable locking device, are screwed out so far that the Crossbars 8 are completely out of mesh with the crossbars 7. in that case the second part 2 can be pulled out from the first part 1 to the desired amount. For the fastening, again the screw spindles 15 are screwed in so far toward the crossbars that the

longitudinal beams

5 and 6 engage on the transverse sections 10 of the longitudinal beams 3 and 4. respectively, and therewith also the upper side of the Crossbars 8 lies level with the upper side of the crossbars 7.

Of course it is also possible to provide locking devices on both ends of the longitudinal beams 3 and 4, so that also the other end of the first part can be connected with a third part formed as the second part 2. These locking devices coordinated to a third part are in a suitable manner formed the same as the locking devices which are coordinated to the second part 2. It is yet also possible to form them differently, for example in the form of disc cams, which also can be provided on the end pointing to the second part 2.

The embodiment example schematically illustrated in FIG, 4 can fundamentally be formed as that according to FIGS. 1 to 3. Additionally there are present merely two hand rails and 21, which are necessary for protection aginst falling, if the working scaffold or platform exceeds a predetermined height. The

rails

20 and 21 are formed (e.g., as on certain bridges] such that they also strengthen the plank itself and increase the load or carrying capacity of the longitudinal struts, thus forming supporting or stiffening parts of the plank. In order to facilitate the assembling, the rails coordinated to the first part are articulated to this part, and indeed such that the rail 20 can be articulated on the upper side, and the rail 21, on the lower side. in this manner one attains a compact arrangement for transportation.

Another embodiment form of a length adjustable plank, as illustrated in FIGS. 5 and 6. comprises a first part designated as a unit by the reference number 101 and a second part designated as a unit by the reference number 102, each part comprisiing two

longitudinal beams

103 and 105, respectively, lying parallel to each other and spaced from each other, as well as

transverse beams

107 and 108, respectively, extending perpendicularly to the longitudinal beams, which transverse beams are rigidly connected with the longitudinal beams.

The

transverse beams

107 and 108, respectively, are formed by the raised sections of corrugated type shaped plates or

sheets

122 and 123, which sheets are supported on the longitudinal beams. In the embodiment example these sheets, as well as the longitudinal beams are made of light metal.

As shown in FIG, 6, the

transverse beams

107 and 108 have the same profile, and indeed a trapezoidal profile In the embodiment example the width of the transverse beams measured in the longitudinal direction of the longitudinal beams on the top thereof form ing the actual standing surface is equal to the spacing of adjacent transverse beams from one another in the range of its foot. That is, the width of the top of a trans verse beam is equal to the width of a foot portion, the latter being supported on the longitudinal beams. The width ofthe tops ofthe transverse bearns could yet also be chosen larger than this spacing. One then obtains a larger standing surface for the user,

Since for the length adjustment, the two

parts

101 and 102 must be displaced relative to each other crosswise to their longitudinal direction so far until the transverse beams 108, which are supported on the inner lying longitudinal beams, are out of mesh with the transverse beams 107, the width of the plates 123 measured in the longitudinal direction of the transverse beam, likewise as the spacing of the inner lying longitudinal beams 105 from each other, is somewhat smaller than the open spacing of the outer lying longitudinal beams 103.

As shown in PK]. 5, the two

plates

122 and 123, in each of the ranges 122' and 123', respectively, forming the top of the transverse beams and therewith the actual standing surface, and in the deepest ranges 122" and 123", respectively, lying thus on the longitudinal beams, are provided with a row of holes extending in the direction of the transverse beams.

The locking device, by means of which the two

parts

101 and 102 are held in the condition of use, thus the position illustrated in FIG. 6, has in the embodiment example four eccentrics or cam discs [15, of which re spectively two are arranged on a common shaft 125, which is rotatably mounted in the outer lying longitudinal beams 103 and which extends in the longitudinal direction of the transverse beams. A connection rod 126 is articulated on its both ends with two swinging le vers, respectively, arranged rigidly on the one and the other shaft, respectively, and makes possible a simultaneous rotation of all eccentrics during the drive only of one of the two shafts. Each eccentric is arranged between the bottom side of a longitudinal beam 105 and an inwardly pointing transverse section of one of the outer lying longitudinal beams 103. Thereby the eccentrics can act directly on the inner lying longitudinal beams 105. The eccentrics end in a plane surface, in order to guarantee that they do not unintendedly turn out from that position in which they hold the two

parts

101 and 102 in the use position.

While 1 have disclosed several embodiments of my invention, it is to be understood that these embodiments are given only by way of illustration and not in a limiting sense.

I claim: 1. A length adjustable plank, comprising at least two parts, including a first part and a second part, adjustably disposed relative to each other in a longitudinal direction thereof,

each of said parts comprises two longitudinal beams constituting profile rods arranged parallel and spaced from each other, and transverse beams having upper surfaces and forming a standing surface for a user, said transverse beams covering at least partially on top of said longitudinal beams and operatively connecting the latter to each other,

said longitudinal beams of said two parts, respectively, forming cooperatively a longitudinal guide. said longitudinal beams of said second part being guided between said longitudinal beams of said first part, said longitudinal beams of said first part constituting outer disposed longitudinal beams and said longitudinal beams of said second part constituting inner disposed longitudinal beams,

the length of said transverse beams of said first part on top of said outer disposed longitudinal beams being equal to the width of the plank.

the length of said transverse beams of said second part on top of said inner disposed longitudinal beams being a little smaller than the open spacing between said outer disposed longitudinal beams.

securing means for releaseabl fixing said inner disposed longitudinal beams in position relative to said first part in a use condition of said plank such that said transverse beams, respectively, of said second and first parts, respectively. on top of said inner and outer disposed longitudinal beams. respectively, mesh with one another, in a manner that the upper surfaces of said transverse beams, respectively. lie substantially in a common plane.

2. The length adjustable plank. as set forth in claim 1, wherein said longitudinal beams are made of light metal. 3. The length adjustable plank, as set forth in claim 1, wherein said transverse beams constitute light metal profile members. 4. The length adjustable plank, as set forth in claim I, wherein said transverse beams are spaced from each other by a distance corresponding substantially to their width.

5. The length adjustable plank, as set forth in claim 1. wherein the height of said inner disposed longitudinal beams is smaller than the height of said outer disposed longitudinal beams at least by the height of said transverse beams of said second part. 6. The length adjustable plank, as set forth in claim 1. wherein said transverse beams of said second part on top of said inner disposed longitudinal beams are formed by raised sections of at least one corrugated shaped sheet. 7. The length adjustable plank, as set forth in claim 6, wherein said transverse beams of said first part on top of said outer disposed longitudinal beams are formed by raised sections of at least one corrugated shaped other sheet. the profile of which is complementary to the profile of said at least one sheet forming said transverse beams of said second part on top of said inner disposed longitudinal beams. 8. The length adjustable plank, as set forth in claim 6, wherein the profile of said at least one sheet in cross section is a trapezoidal shape of a corresponding of said transverse beams. 9. The length adjustable plank. as set forth in claim 6, wherein said at least one sheet is formed with holes therein. 10. The length adjustable plank, as set forth in claim 9, wherein said holes are at least in a portion of said at least one sheet which forms said standing surface and in a lowest disposed portion thereof. H. The length adjustable plank. as set forth in claim I, wherein the width of said transverse beams measured in the longitudinal direction of said longitudinal beams is different from the spacing of said transverse beams from one another. 12. The length adjustable plank, as set forth in claim I, wherein said securing means constitutes a clamping device. 13. The length adjustable plank, as set forth in claim 12. wherein said clamping device includes a spindle guided in a threaded bore. 14. The length adjustable plank, as set forth in claim 12, wherein said clamping device constitutes rotatable cam discs. 15. The length adjustable plank, as set forth in claim 14, wherein said cam discs are operatively coupled with each other for simultaneous actuation.

16. The length adjustable plank, as set forth in claim 1, further comprising a hand rail articulated to each of said outer disposed longitudinal beams, respectively. s: a:

Claims

1. A length adjustable plank, comprising at least two parts, including a first part and a second part, adjustably disposed relative to each other in a longitudinal direction thereof, each of said parts comprises two longitudinal beams constituting profile rods arranged parallel and spaced from each other, and transverse beams having upper surfaces and forming a standing surface for a user, said transverse beams covering at least partially on top of said longitudinal beams and operatively connecting the latter to each other, said longitudinal beams of said two parts, respectively, forming cooperatively a longitudinal guide, said longitudinal beams of said second part being guided between said longitudinal beams of said first part, said longitudinal beams of said first part constituting outer disposed longitudinal beams and said longitudinal beams of said second part constituting inner disposed longitudinal beams, the length of said transverse beams of said first part on top of said outer disposed longitudinal beams being equal to the width of the plank, the length of said transverse beams of said second part on top of said inner disposed longitudinal beams being a little smaller than the open spacing between said outer disposed longitudinal beams, securing means for releaseably fixing said inner disposed longitudinal beams in position relative to said first part in a use condition of said plank such that said transverse beams, respectively, of said second and first parts, respectively, on top of said inner and outer disposed longitudinal beams, respectively, mesh with one another, in a manner that the upper surfaces of said transverse beams, respectively, lie substantially in a common plane.

2. The length adjustable plank, as set forth in claim 1, wherein said longitudinal beams are made of light metal.

3. The length adjustable plank, as set forth in claim 1, wherein said transverse beams constitute light metal profile members.

4. The length adjustable plank, as set forth in claim 1, wherein said transverse beams are spaced from each other by a distance corresponding substantially to their width.

5. The length adjustable plank, as set forth in claim 1, wherein the height of said inner disposed longitudinal beams is smaller than the height of said outer disposed longitudinal beams at least by the height of said transverse beams of said second part.

6. The length adjustable plank, as set forth in claim 1, wherein said transverse beams of said second part on top of said inner disposed longitudinal beams are formed by raised sections of at least one corrugated shaped sheet.

7. ThE length adjustable plank, as set forth in claim 6, wherein said transverse beams of said first part on top of said outer disposed longitudinal beams are formed by raised sections of at least one corrugated shaped other sheet, the profile of which is complementary to the profile of said at least one sheet forming said transverse beams of said second part on top of said inner disposed longitudinal beams.

8. The length adjustable plank, as set forth in claim 6, wherein the profile of said at least one sheet in cross section is a trapezoidal shape of a corresponding of said transverse beams.

9. The length adjustable plank, as set forth in claim 6, wherein said at least one sheet is formed with holes therein.

10. The length adjustable plank, as set forth in claim 9, wherein said holes are at least in a portion of said at least one sheet which forms said standing surface and in a lowest - disposed portion thereof.

11. The length adjustable plank, as set forth in claim 1, wherein the width of said transverse beams measured in the longitudinal direction of said longitudinal beams is different from the spacing of said transverse beams from one another.

12. The length adjustable plank, as set forth in claim 1, wherein said securing means constitutes a clamping device.

13. The length adjustable plank, as set forth in claim 12, wherein said clamping device includes a spindle guided in a threaded bore.

14. The length adjustable plank, as set forth in claim 12, wherein said clamping device constitutes rotatable cam discs.

15. The length adjustable plank, as set forth in claim 14, wherein said cam discs are operatively coupled with each other for simultaneous actuation.

16. The length adjustable plank, as set forth in claim 1, further comprising a hand rail articulated to each of said outer disposed longitudinal beams, respectively.