IL286609A - Scaffold surface retaining device - Google Patents

Description

34414- 1 - SCAFFOLD SURFACE RETAINING DEVICE FIELD OF THE INVENTION: The present invention relates to the field of building construction. More particularly, the present invention relates to a scaffold plank retaining device for securing scaffold board(s) to a scaffold structure.

BACKGROUND OF THE INVENTION: Scaffold structures are used to support a work crew and materials to aid in the construction, maintenance and repair of buildings, bridges and all other man-made structures. Working scaffolds provide a safe working platform and access suitable for work crews to carry out their work. Scaffold structures usually comprise a plurality of vertical and horizontal bars (e.g. rails, tubes) and a plurality of scaffold couplers (e.g. fittings which hold the bars together.

Several scaffold working platforms comprise a plurality ofadjacent boards or planks (used herein interchangeably) providing a working surface for scaffold users to stand onand walk on during their construction work. These boards typically rest on dedicated portions of the scaffold structure and form a treading floor. The boards are secured to the scaffold bars.

As scaffold structures are temporary structures, making them safe for use has been an ongoing challenge. Particularly, the boards forming the treading floors are prone to come out of place and thus may be hazardous to workers. Extreme weather conditions such as strong winds 34414- 2 - may displace the boards (e.g. dislodge the boards from place) and cause danger to the workers. Intentional sabotage of scaffold structures may also cause displacement of the boards and be a danger to workers. Thus, it has been an ongoing challenge to provide means that secure and prevent sudden retrieval of the boards.

WO2000071836 relates to a scaffolding wherein the decking unit has first and second end parts each of which cooperate with a respective transom to support the decking unit and to restrain relative angular movement between an end part and a respective transom.

JP03210155U relates to a board for scaffolds, positioned between scaffold boards by which connection arrangement is carried out, and support in insertion portion penetrates in location which becomes cross-beam side when board is positioned to span.

JP06491449B2 relates to Suspended scaffolds used in height work such as building and bridge, has scaffold-board and handrail locking mechanism which makes support bar attach or detach scaffold board and lengthwise frames.

GB2466795A relates to a retaining strap of molded plastic to restrain scaffolding boards within a conventional scaffolding arrangement, whereby in use the strap is attached to a ledger underneath the scaffolding boards, and further engaged between a toe board and the scaffolding boards. The strap can be used at the junction between two scaffolding boards, and features a tapering cross-sectional 34414- 3 - profile to minimize trip hazards. GB2321491B and GB2432883A also relate to a strap for retaining scaffolding boards.

JP04113908B2 relates to a skirting board for closing edges of scaffold board, has support plate positioned at lower edge of skirting board main housing, and installation fastener fitted to lateral edge of frame.

US4187929A relates to a stabilizer for scaffold floor, is elongated C-shaped clamp to fit over planks constituting floor and has bolt at open end to tighten clamp.

GB2479944A relates to a cross beam for platform structure e.g. hop up platform, has shaped notch which is provided for receiving and locating scaffolding tube and locking portion is operated to selectively engage scaffolding tube.

AU2006200424A1 relates to a scaffolding for use in a construction site, has connector extending between adjacent end of scaffold boards on underside of portion of scaffold frame structure.

US6354402B1 relates to a securing scaffolding assembly with planks to avoid theft, involves holding planks in place using hold down components which provide increased front- to-rear mechanical strength to scaffolding.

GB2158497A, JP2020139292A, US2775490A, JP05558056B2, US20090127027A1, JP04124548B2, GB2243186A, and US2928443A relate to other plank retaining devices. 34414- 4 - Additionally, scaffold elements that hold the boards, may be unintentionally dislodged. Some prior art methods include using a locking "R" pin (explained in detail hereinbelow) for holding them in place. However, the prior art techniques do not provide sufficient means for securing the boards (and elements that hold the boards) to the scaffold structures in a safe and efficient manner.

It is therefore an object of the present invention to provide a method and means for securing a scaffold board to its dedicated scaffold structure that it rests on.

It is a further object of the present invention to provide a method and means for securing the elements that hold the boards in place.

It is a further object of the present invention to provide a method and means for securing a scaffold board to its dedicated scaffold structure in a simple, easy to use, user friendly, cost effective manner.

Other objects and advantages of the present invention will become apparent as the description proceeds.

SUMMARY OF THE INVENTION: The present invention relates to a device and method for retaining a scaffold treading floor surface to the scaffold structure. The present invention device comprises an upper retaining surface engageable with the treading floor surface to be retained. The upper retaining surface presses down on the treading floor surface and prevents the 34414- 5 - treading floor surface from dislodging out of place. The present invention device further comprises a bottom securing element configured to move between two positions:A) a non-securing position where the securing element does not connect to the scaffold structure; andB) a locking position where the securing element firmly secures the retaining device (and thereby the treading floor surface) to the scaffold structure.

Preferably, the securing element comprises side hooks configured to hook the retaining device to the side structural elements (e.g., bars) of the scaffold structure. The top upper retaining surfaces and corresponding bottom hooks apply a downward and upward force respectively thereby firmly retaining the treading floor surface to the scaffold structure and securing it thereto. The present invention also relates to a system comprising a scaffold structure along with the retaining device as explained herein. The present invention further comprises a method for applying the retaining device as explained herein to the scaffold structure.

The present invention relates to a scaffold surface retaining device comprising:- an elongated arm comprising one or more horizontal retaining surfaces protruding sideways therefrom;- two vertical standard engaging elements, each of which is attached to a corresponding edge of the elongated arm;- two securing elements, each of which is connected to a corresponding vertical standard engaging element of said two vertical standard engaging elements; 34414- 6 - wherein each of said securing elements are configured to be displaced between a non-securing position and a securing position.

Preferably, the retaining surface(s) protrude sideways from the top of the elongated arm.

Preferably, each vertical standard engaging element comprises a vertical curved surface.

Preferably, the vertical curved surface has a partially circular cross-section.

Preferably, the partially circular cross-section is a half­circle cross-section.

Preferably, each standard engaging element further comprises a first flat vertical surface attached to a first edge of the vertical curved surface and a second flat vertical surface attached to a second edge of the vertical curved surface.

Preferably, both flat vertical surfaces are parallel to one another.

Preferably, the vertical standard engaging element has a common vertical height.

Preferably, the vertical standard engaging elements are each attached to a corresponding edge of the elongated arm such that the elongated arm edge engages the external part of the vertical curved surface. 34414- 7 - Preferably, each securing element is connected to the external side of a corresponding flat vertical surface of the flat vertical surfaces.

Preferably, both securing elements are each placed on opposite sides of said device in relation to its longitudinal axis.

Preferably, each securing element comprises an elongated tiltable arm extendable vertically downwards.

Preferably, each tiltable arm comprises a hook facing inwards.

Preferably, each tiltable arm comprises a handle extending sideways from an upper portion therefrom.

Preferably, each handle is substantially perpendicular to the longitudinal axis of the retaining device.

Preferably, the scaffold surface retaining device further comprises a spring connected at a first and second connection point, wherein said first connection point is either on:a. an upper portion of the tiltable arm; orb. on the handle;wherein said second connection point is on the corresponding flat vertical surface that the securing element is attached to;wherein the first connection point is closer to the center of the device than the second connection point. 34414- 8 - Preferably, the non-securing position is when the hooks are displaced away from the center of the device; and wherein the securing position is when the hooks are displaced towards the center of the device.

Preferably, each securing element connected to the external side of its corresponding flat vertical surface is by means of the tiltable arm being connected to said corresponding flat vertical surface by means of a revolute joint connection.

Preferably, the revolute joint is placed at an upper portion of the tiltable arm.

The present invention relates to a system scaffold structure comprising at least two adjacent cuboid shaped scaffold bays comprising:- a first pair of parallel vertical standards placed attwo corners of a first bay of said two adjacent bays;- a second pair of parallel vertical standards placed attwo corners of a second bay of said two adjacent bays;- a third pair of parallel vertical standards placed attwo common corners of the first and second bays;wherein each of said bays comprises:- a horizontal platform unit;- a treading floor surface resting on said horizontal platform unit;wherein said scaffold structure further comprises a scaffold surface retaining device as explained herein (according to any one of its embodiments explained herein), 34414- 9 - placed between the horizontal platform units of said bays; andwherein the retaining surfaces are configured to engage the top of said treading floor surfaces.

Preferably, each treading floor surface is a wooden surface.

Preferably, the horizontal platform units each comprises two parallel longitudinal bars and a plurality of transvers bars, each transvers bar is attached between the two longitudinal bars.

Preferably, the third pair of parallel vertical standards each comprise a pair of side ear surfaces extending sideways from the respective vertical standards;each pair of side ear surfaces is parallel to the other pair of side ear surfaces;wherein the interior of two vertical standard engaging elements each engages a corresponding vertical standard of said third pair of parallel vertical standards and rest on a corresponding pair of side ear surfaces of said pair of side ear surfaces.

Preferably, each side ear surface comprises a pin element extending upwards therefrom;wherein each horizontal platform unit longitudinal bar comprises two holes, each hole near a corresponding edge of said longitudinal bar;wherein each longitudinal bar rests on a corresponding side ear surface of said side ear surfaces; and 34414- 10 - wherein each pin element passes through a corresponding hole of said holes.

Preferably, each vertical standard engaging element comprises a vertical curved surface;wherein each standard engaging element further comprises a first flat vertical surface attached to a first edge of the vertical curved surface and a second flat vertical surface attached to a second edge of the vertical curved surface;wherein each securing element comprises an elongated tiltable arm extendable vertically downwards;wherein each tiltable arm comprises a hook facing inwards;wherein the hook is engageable with the bottom of a corresponding side ear surface of the side ear surfaces.

Preferably, the hook engages the bottom of a corresponding side ear surface of the side ear surfaces in the securing position thereby securing the treading floor surface to the scaffold structure.

Preferably, the hook engages the bottom of a corresponding side ear surface of the side ear surfaces in the securing position thereby securing the platform unit to the scaffold structure.

The present invention relates to a method for securing a scaffold treading floor surface to a scaffold structure, the method comprises:- providing a scaffold structure as explained herein;- positioning the retaining device in between the two horizontal platform units; 34414- 11 - - positioning the securing elements of the retaining device into the non-securing position;- engaging and pressing down on the top of the scaffold treading floor surfaces by means of the one or more horizontal retaining surfaces;- positioning the securing elements of said retaining device into the securing position (a locking position).

Preferably, positioning the securing elements of the retaining device into the non-securing position comprises displacing the tiltable arm hook outwards; and wherein positioning the securing elements of the retaining device into the securing position comprises displacing the tiltable arm hooks inwards such that the hooks each engagethe bottom of a corresponding side ear surface of the sideear surfaces.

Preferably, displacing the tiltable arm hooks inwards is carried out by a spring.

BRIEF DESCRIPTION OF THE DRAWINGS: The present invention is illustrated by way of example in the accompanying drawings, in which similar references consistently indicate similar elements and in which: - Figs. 1A-1D illustrates an embodiment of the scaffold structure alone.- Fig. 1E illustrates an embodiment of the ear pins and ear surfaces.- Figs. 2A-2E show prior art approaches. 34414- 12 - - Figs. 3A-3D show an embodiment of the scaffold surface retaining device of the present invention.- Figs 4A-4E show the scaffold structure with the retaining device according an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION: The present invention relates to a scaffold board retaining device configured to be used with a scaffold structure. The present invention further relates to a scaffold structure comprising one or more of the board retaining device. Figs. 1A-1E show the present invention scaffold structure (or parts thereof) that the scaffold board retaining device may be incorporated therewith.

Fig. 1A shows a scaffold structure 20with two bays on a lower deck and two bays on an upper deck (parallel to those on the lower deck). Of course, the present invention may comprise additional bays on each deck and with additional similar decks above, mutatis mutandis. The present invention scaffold structure 20comprises two groups of vertical standards 1 , each group aligned along a straight horizontal line (row), both of which are parallel to one another. Each vertical standard 1is typically comprised of a plurality of sub-standard elements one on top of the other (connected as known in the art). The vertical standards 1of the first group are each parallel to a corresponding vertical standard 1of the second group. Each vertical standard 1is preferably mounted on a corresponding adjustable base 2 (e.g., base jacks). 34414- 13 - Each scaffold structure 20bay is bounded by two adjacent vertical standards 1of one group and two corresponding (parallel) adjacent vertical standards 1of the other group. The bottom deck scaffold structure 20bays shown are each bounded by an upper horizontal platform unit 4(of the upper deck) and a lower horizontal platform unit 4(of the lower deck). The platform unit 4comprises two parallel longitudinal bars 4Land a plurality of transvers bars 4T (preferably having the form of cylindrical rods), each attached between the two longitudinal bars 4Land are perpendicular to them. The scaffold structure 20comprises a treading floor surface, preferably a wooden surface 11 . The wooden surface 11preferably comprises a plurality of adjacent parallel elongated laths, each lath connected to its adjacent lath(s), optionally, by a transverse connecting lath. Typically, the plurality of adjacent parallel elongated laths are spaced apart. According to one embodiment, the wooden surface 11is comprised of two longitudinally adjacent sub-surfaces (adjacent in the same scaffold bay). The sub-surfaces each comprise three spaced apart longitudinal laths connected by two or more transverse laths beneath the longitudinal laths.Optionally, the wooden surface 11may comprise a plurality of connected elongated touching laths. Alternatively, the wooden surface 11may comprise a single wide board (rather than a plurality of connected narrow laths).

The wooden surface 11comprises a surface area substantially equal to that of the horizontal area of a single bay. The wooden surface 11rests on the platform unit 4(on the plurality of transvers bars 4T ). The wooden surface 11forms a horizontal timber platform unit of a 34414- 14 - single bay. Two wooden surfaces 11on each deck are placed adjacent one to the other (one in each bay) forming the treading floor. Each wooden surface 11has a rectangular shape.

Fig. 1B shows the scaffold structure 20of Fig. 1A in explosion view. Fig. 1C shows the vertical standards 1and the bottom deck wooden surfaces 11of the scaffold structure 20 .

The vertical standards 1comprise a plurality of vertically spaced apart pairs of side ear surfaces 24extending sideways therefrom, shown in Fig. 1E (a close-up of reference item C in Fig. 1C). Preferably, each side ear surface 24of the pair extends sideways and is placed on the same imaginary surface as the other side ear surface 24 of the pair (i.e., both surfaces of the pair have 1degrees angle therebetween). Each of the pairs of side ear surfaces 24of all of the vertical standards 1of the first group of standards 1are preferably on a first common imaginary surface. Each of the pairs of side ear surfaces of all of the vertical standards 1of the second group of standards 1are preferably on a second common imaginary surface. The first common imaginary surface is preferably parallel to the second common imaginary surface.

Each side ear surface 24preferably comprises a pin element 25extending upwards therefrom (preferably cylindrical). Bay Length guardrails 3and transverse guardrails 5 (e.g., ledgers) are mounted on corresponding side ear surfaces 24 by means of placing them such that the ear pins 25of the corresponding surfaces penetrate corresponding bores within 34414- 15 - the guardrails, thereby having the guardrails rest on the ear surfaces 24 .

The scaffold structure further comprises a diagonal brace 7 (e.g., scaffold tubes) attached to a plurality of vertical standards 1(of a single group of standards 1 ) by means of couplers 8at the "intersecting" areas (i.e., fittings which hold the bars together at their touching locations, e.g. swivel couplers). The couplers 8firmly couple the diagonal brace 7 to the corresponding vertical standards 1 at the touching locations. The scaffold structure may further comprise a wall connection flange 10 , longitudinaltoe boards 6 , transverse toe boards 15 , trapdoor/opening platform structures, ladders and the like, as known in the art.

Furthermore, horizontal platform unit 4two longitudinal bars 4Leach comprises a hole 4LHnear its edges (one hole 4LHnear each edge), such that each longitudinal bar 4Lis mounted on two corresponding side ear surfaces 24by means of placing the holes 4LHsuch that the ear pins 25of the corresponding surfaces penetrate the corresponding holes 4LHon longitudinal bars 4L , thereby having the longitudinal bars 4Lrest on these corresponding ear surfaces 24 .

Figs 2A-2E show an example of a prior art securing method that is carried out with the above explained system. Fig. 2A shows a scaffold structure 120(with several elements similar to that of scaffold structure 20 , e.g. side ear surfaces 124equivalent to side ear surfaces 24 ; ear pins 125equivalent to ear pins 25 ; horizontal platform unit 4 34414- 16 - equivalent to horizontal platform unit 104 ; etc., mutatis mutandis). The longitudinal bars 104Lare mounted on corresponding side ear surfaces 124by means of placing them such that the ear pins 125of the corresponding surfaces 124penetrate the corresponding holes 104LHof the longitudinal bars 104L , thereby having the scaffold longitudinal bars 104Lrest on the top of the corresponding ear surfaces 124 . Each ear pin 125comprises a horizontal bore 125bthat extends horizontally therethrough. An "R" shaped pin 130(side view of which is shown in Fig. 2B; top view of which is shown in Fig. 2C) is inserted within horizontal bore 125b . Thus, if the longitudinal bars 104L were to be lifted, it would not be removed from the ear pins 125but would stop when the longitudinal bars 104L hole 104LHwould reach the "R" shaped pin 130 . Close ups of reference items J and I are shown in Figs. 2D and 2E respectively. Fig. 2E shows the longitudinal bars 104Lin place, secured by the "R" shaped pin 130 .

More specifically, the straight portion of the "R" shaped pin 130is inserted within the horizontal bore 125band the curved part of the "R" shaped pin 130curves around ear pin 125 . The "R" shaped pin 130has a contraction force such that the curved part of the "R" shaped pin 130and the straight part of the "R" shaped pin tend to move one towards the other. Thus, the curved part of the "R" shaped pin 130presses towards the outer part of the ear pin 125 and the straight portion of the "R" shaped pin 130presses towards a corresponding side portion of the horizontal bore 125b . A securing string 132is attached at one end to the "R" shaped pin 130and at its other end to a corresponding vertical standard 101 . Fig. 2D shows this mechanism for 34414- 17 - securing the Bay Length guardrails rails 103(shown in a clear manner easy to understand the mechanism). Thus, apparently, these "R" shaped pins 130provide a securing means for the longitudinal bars 104L(Fig. 2E).

However, these "R" shaped pins 130are limited in strength. External factors, such as strong winds, sudden impact, etc., are liable to overcome the "R" shaped pins 130 securing, and the longitudinal bars 104Lmay be dislodged (e.g. breaking/folding the "R" shaped pin 130 ) from the pins 130 , thus causing a partial fall-apart of the scaffold structure and a hazard to the construction workers. The wooden surfaces 111placed on the horizontal platform unit 104may come apart from the horizontal platform unit 104or may lose stability and fall apart from the scaffold structure 120(with or without the horizontal platform unit 104 ). Therefore, there is a great need to provide an extra strong securing means that can prevent sudden retrieval of the longitudinal bars 104L .

The present invention relates to a scaffold surface retaining device 50 , shown in Figs. 3A-3D. Figs. 4A-4D show similar drawings to those of Figs. 1A-1D respectively, but including the retaining device 50 , mutatis mutandis. The reference numbers of the scaffold structures and elements of Figs. 4A-4D are similar to those of Figs. 1A-1D respectively, mutatis mutandis.

The retaining device 50comprises an elongated arm 55 configured to be placed between two adjacent horizontal platform units 4and hold the horizontal platform units 4 in place. As the adjacent horizontal platform units 4each 34414- 18 - comprises a wooden surface 11resting thereon, the elongated arm 55is configured to hold the wooden surfaces 11in place. The elongated arm 55length is placed along the scaffold structure bay width. The elongated arm 55 comprises one or more horizontal retaining surfaces 56 thereon (i.e. such that the one or more horizontal retaining surfaces 56are placed on top of the elongated arm 55 ). Figs. 3A-3D show an example of two spaced apart horizontal retaining surfaces 56having a square shape. The horizontal retaining surfaces 56may be in the form of other shapes, for example rectangular, circular, elliptic, etc. The horizontal retaining surfaces 56protrude sideways from the elongated arm 55main body portion such that they may each engage a first wooden surface 11on one side of the elongated arm 55and a second wooden surface 11on theother side of the elongated arm 55(each wooden surface 11 resting on a different horizontal platform unit 4 ). The middle of arm 55is referred to herein as the "middle of device 50 " or as "the center of device 50 ".

In the embodiment with the wooden surface 11comprised of two longitudinally adjacent sub-surfaces the configuration of device 50as shown in the drawings is advantageous. Each of the two horizontal retaining surfaces 56retains two adjacent sub-surfaces of different bays thereby having four sub-surfaces retained by a single device 50 . A first sub­surface adjacent to a second sub surface along the same bay; a third sub-surface on an adjacent bay, adjacent to the first sub-surface, wherein the first and third sub­surfaces are retained by a first retaining surface 56of device 50 . A fourth sub-surface adjacent to the third sub surface along the same bay; the second sub-surface is on an 34414- 19 - adjacent bay, adjacent to the fourth sub-surface, wherein the second and fourth sub-surfaces are retained by the second retaining surface 56of device 50 .

With reference to Figs. 3A-3D which is a preferable embodiment, the distance between the first horizontal retaining surface 56and one edge (the first edge) of the elongated arm 55is the same as the distance between the second horizontal retaining surface 56and the other (second) edge of the elongated arm 55 . The retaining surfaces 56are configured to hold the wooden surfaces 11 in place and prevent their dislodgment out of place.

The retaining device 50further comprises two vertical standard engaging elements 52 , each of which is attached to a corresponding edge of the elongated arm 55(i.e., a first engaging elements 52attached to the first edge of the elongated arm 55 ; a second engaging elements 52attached to the second edge of the elongated arm 55 ).

Each standard engaging element 52comprises a vertical curved surface 52cpreferably having a partially circular cross-section (e.g., a half-circle cross-section). Each standard engaging element 52further comprises a first flat vertical surface 52fattached to a first edge of the vertical curved surface 52cand a second flat vertical surface 52fattached to a second edge of the vertical curved surface 52c . Preferably, both flat vertical surfaces 52fare parallel to one another. Each flat vertical surface 52fmay have the shape of a square, rectangle or other shapes. Preferably, the vertical standard engaging element 34414- 20 - 52has a common vertical height (along its entire horizontal length).

The vertical standard engaging elements 52are each attached to the corresponding elongated arm 55edge such that the arm edge engages the external part of the vertical curved surface 52c . Thus, the elongated arm 55edge has a curved shape corresponding (complementary) to that of the vertical curved surface 52c . Preferably, the flat vertical surfaces 52fare parallel to the elongated arm 55length direction. Typically, a flat vertical surface 52f (belonging to a first standard engaging element 52 ) is on the same imaginary plane as a corresponding flat vertical surfaces 52fof the other standard engaging element 52 . Thus, two flat vertical surfaces 52fare on a common imaginary plane parallel to an imaginary plane where the other two flat vertical surfaces 52fare placed on.

The retaining device 50is configured to be placed such that its standard engaging elements 52engage two corresponding (parallel) scaffold standards 1(along the width of the scaffold structure bay). Each of the scaffold standards 1engage the inner part of a corresponding vertical curved surface 52c(preferably complementary thereto), and thus the length of the retaining device 50is structured accordingly (adapted to be placed along the transverse/width of the bay between two corresponding parallel standards 1and between two adjacent horizontal platform units 4 ).

The retaining device 50further comprises two securing elements 60 , each of which is attached to a corresponding 34414- 21 - standard engaging element 52 . Preferably, the securing elements 60are each attached to a corresponding flat vertical surface 52f (i.e., a first securing element 60 attached to a flat vertical surface 52fof one of the standard engaging elements 52 ; a second securing element 60 attached to a flat vertical surface 52fof the other standard engaging element 52 ). The securing elements 60areeach attached to the external side of its corresponding flat vertical surface 52f .

Preferably, both securing elements 60are each placed on opposite sides in relation to the longitudinal axis of the retaining device 50(one on a right side and the other on a left side in relation to the length). In other words, thesecuring element 60of a first standard engaging element 52 is place on a first flat vertical surface 52f ; and the second securing element 60of the second standard engaging element 52is place on a second flat vertical surface 52f ; wherein these first and second flat vertical surfaces 52f are not placed on flat vertical surfaces 52fon a common imaginary plane, but rather on flat vertical surfaces 52f each on parallel imaginary planes. This configuration increases the securing ability of the device, as will become apparent hereinbelow.

The securing element 60comprises an elongated tiltable arm 60aextendable vertically downwards and configured to tilt. The securing element 60is attached to the flat vertical surface 52fby means of a revolute joint connection such that the arms 60aare each rotatable around an axis of the corresponding revolute joint 60j(the rotation axis of the arms 60abeing the rotation axis of the revolute joint 34414- 22 - 60j ). The revolute joint 60jis preferably placed at an upper portion of the arm 60a , such that the length of the portion of the arm 60abeneath the revolute joint 60jis greater than length of the portion of the arm 60aabove the revolute joint 60j .

Each securing element 60comprises a hook 60hat the bottom of arm 60a . Each hook 60hmay be an extension that protrudes inwards from the bottom of arm 60a . The hooks 60h face inwards, i.e., protrude towards the other (opposite) side of retaining device 50(towards the center of the device 50 ).

Each securing element 60comprises a handle 60dextending sideways from an upper portion of arm 60a (e.g., from thetop of arm 60a ), such that handle 60dprotrudes sideways from the longitudinal axis of retaining device 50 . Preferably, the handle 60dis in the form of an elongated rod or an elongated cuboid. Preferably, the handle 60dis substantially perpendicular to the longitudinal axis of retaining device 50 . The handle 60dextends from arm 60a from a location above the revolute joint 60j .

According to a preferred embodiment, the retaining device 50further comprises a spring 61 (e.g., coil spring)connected at one side to an upper portion of securing element 60and at the other side to another point on the same flat vertical surface 52f , said point being closer to the edge of flat vertical surface 52f(away from the other standard engaging elements 52 , away from the center of device 50 ). The connection to the upper portion of securing element 60may be by connection to an upper portion of arm 34414- 23 -

Claims (30)

34414

1.CLAIMS: 1. A scaffold surface retaining device comprising:- an elongated arm comprising one or more horizontal retaining surfaces protruding sideways therefrom;- two vertical standard engaging elements, each of which is attached to a corresponding edge of the elongated arm;- two securing elements, each of which is connected to a corresponding vertical standard engaging element of said two vertical standard engaging elements;wherein each of said securing elements are configured to be displaced between a non-securing position and a securing position.

2. The scaffold surface retaining device according to claim 1, wherein the retaining surface(s) protrude sideways from the top of the elongated arm.

3. The scaffold surface retaining device according to claim1, wherein each vertical standard engaging element comprises a vertical curved surface.

4. The scaffold surface retaining device according toclaim 3, wherein the vertical curved surface has a partially circular cross-section.

5. The scaffold surface retaining device according to claim 4, wherein the partially circular cross-section is a half­circle cross-section.

6. The scaffold surface retaining device according to claim 3, wherein each standard engaging element further comprises a first flat vertical surface attached to a first edge of 34414 the vertical curved surface and a second flat vertical surface attached to a second edge of the vertical curved surface.

7. The scaffold surface retaining device according to claim 6, wherein both flat vertical surfaces are parallel to one another.

8. The scaffold surface retaining device according to claim 6, wherein the vertical standard engaging element has a common vertical height.

9. The scaffold surface retaining device according to claim 6, wherein the vertical standard engaging elements are each attached to a corresponding edge of the elongated arm such that the elongated arm edge engages the external part of the vertical curved surface.

10. The scaffold surface retaining device according to claim 6, wherein each securing element is connected to the external side of a corresponding flat vertical surface of the flat vertical surfaces.

11. The scaffold surface retaining device according to claim 6, wherein both securing elements are each placed on opposite sides of said device in relation to its longitudinal axis.

12. The scaffold surface retaining device according to claim 6, wherein each securing element comprises an elongated tiltable arm extendable vertically downwards. 34414

13. The scaffold surface retaining device according to claim 12, wherein each tiltable arm comprises a hook facing inwards.

14. The scaffold surface retaining device according to claim 13, wherein each tiltable arm comprises a handle extending sideways from an upper portion therefrom.

15. The scaffold surface retaining device according to claim 14, wherein each handle is substantially perpendicular to the longitudinal axis of the retaining device.

16. The scaffold surface retaining device according toclaim 14, further comprising a spring connected at a first and second connection point, wherein said first connection point is either on:a. an upper portion of the tiltable arm; orb. on the handle;wherein said second connection point is on the corresponding flat vertical surface that the securing element is attached to;wherein the first connection point is closer to the center of the device than the second connection point.

17. The scaffold surface retaining device according to claim 16, wherein the non-securing position is when the hooks are displaced away from the center of the device; and wherein the securing position is when the hooks are displaced towards the center of the device. 34414

18. The scaffold surface retaining device according to claim 12, wherein each securing element connected to the external side of its corresponding flat vertical surface is by means of the tiltable arm being connected to said corresponding flat vertical surface by means of a revolute joint connection.

19. The scaffold surface retaining device according to claim 18, wherein the revolute joint is placed at an upper portion of the tiltable arm.

20. A scaffold structure comprising at least two adjacent cuboid shaped scaffold bays comprising:- a first pair of parallel vertical standards placed attwo corners of a first bay of said two adjacent bays;- a second pair of parallel vertical standards placed attwo corners of a second bay of said two adjacent bays;- a third pair of parallel vertical standards placed attwo common corners of the first and second bays;wherein each of said bays comprises:- a horizontal platform unit;- a treading floor surface resting on said horizontal platform unit;wherein said scaffold structure further comprises a scaffold surface retaining device according to claim 1, placed between the horizontal platform units of said bays; andwherein the retaining surfaces are configured to engage the top of said treading floor surfaces.

21. The scaffold structure according to claim 20, wherein each treading floor surface is a wooden surface. 34414

22. The scaffold structure according to claim 20, wherein the horizontal platform units each comprises two parallel longitudinal bars and a plurality of transvers bars, each transvers bar is attached between the two longitudinal bars.

23. The scaffold structure according to claim 22, wherein the third pair of parallel vertical standards each comprise a pair of side ear surfaces extending sideways from the respective vertical standards;each pair of side ear surfaces is parallel to the other pair of side ear surfaces;wherein the interior of two vertical standard engaging elements each engages a corresponding vertical standard of said third pair of parallel vertical standards and rest on a corresponding pair of side ear surfaces of said pair of side ear surfaces.

24. The scaffold structure according to claim 23, wherein each side ear surface comprises a pin element extending upwards therefrom;wherein each horizontal platform unit longitudinal bar comprises two holes, each hole near a corresponding edge of said longitudinal bar;wherein each longitudinal bar rests on a corresponding side ear surface of said side ear surfaces; andwherein each pin element passes through a corresponding hole of said holes. 34414

25. The scaffold structure according to claim 24, wherein each vertical standard engaging element comprises a vertical curved surface;wherein each standard engaging element further comprises a first flat vertical surface attached to a first edge of the vertical curved surface and a second flat vertical surface attached to a second edge of the vertical curved surface;wherein each securing element comprises an elongated tiltable arm extendable vertically downwards;wherein each tiltable arm comprises a hook facing inwards;wherein the hook is engageable with the bottom of a corresponding side ear surface of the side ear surfaces.

26. The scaffold structure according to claim 25, wherein the hook engages the bottom of a corresponding side ear surface of the side ear surfaces in the securing position thereby securing the treading floor surface to the scaffold structure.

27. The scaffold structure according to claim 25, wherein the hook engages the bottom of a corresponding side ear surface of the side ear surfaces in the securing position thereby securing the platform unit to the scaffold structure.

28. A method for securing a scaffold treading floor surface to a scaffold structure, the method comprises:- providing a scaffold structure according to any one of claims 20-25;- positioning the retaining device in between the two horizontal platform units;- positioning the securing elements of the retaining device into the non-securing position; 34414 - engaging and pressing down on the top of the scaffold treading floor surfaces by means of the one or more horizontal retaining surfaces;- positioning the securing elements of said retaining device into the securing position.

29. The method according to claim 28, providing a scaffold structure according to claim 25,wherein positioning the securing elements of the retaining device into the non-securing position comprises displacing the tiltable arm hook outwards; andwherein positioning the securing elements of the retaining device into the securing position comprises displacing the tiltable arm hooks inwards such that the hooks each engage the bottom of a corresponding side ear surface of the side ear surfaces.

30. The method according to claim 29, wherein displacing the tiltable arm hooks inwards is carried out by a spring.