CA2460941A1 - Anchoring device and scaffold assembly including the same - Google Patents

Abstract

An anchoring device for use with a scaffold and a retractable lanyard is disclosed. The device comprises an arm and a tensile member. The arm has a pair of longitudinally-spaced end portions and an intermediate portion, the latter defining a transverse axis, and is mounted to an upper portion of the scaffold in use such that the transverse axis of the arm is disposed substantially horizontally and such that the arm is pivotable about the transverse axis. The mount is such that, at an operative orientation of the arm, one of the end portions of the arm cannot be pivoted lower. The tensile member is connected to span, in use, between said one end portion of the arm and a lower portion of the scaffold, to secure the arm at its operative orientation. The lanyard is securely connected to the other end portion of the arm in use.

Description

ANCHORING DEVICE AND SCAFFOLD ASSEMBLX INCLUDING THE SAME
FIELD OF THE INVENTION
[0001] The present invention relates to the field of fail arrest systems, and more particularly, to fall arrest systems for use with scaffolding.
BACKGROUND OF THE INVENTION

[0002] Scaffolding is widely used in industry and construction. Workers using a scaffold typically rely on some form of fall-arrest system to avoid fall-related injuries.
In circumstances wherein a worker is working on a particular platform for an extended period of time, for example, as might a bricklayer, it is conventional for the worker to don a harness or a belt, and tie off to an adjacent handrail with a suitable fixed-length shock absorbing lanyard. For the purpose of facilitating safe movement of the worker between the scaffold and the ground, it is known to incorporate a ladder in the scaffold, and to use a retractable lanyard suspended from some form of boom secured to the top of the scaffold to cantilever over the ladder. These lanyards include a spring-biased spool of cable or webbing which plays out and automatically retracts and spools as the worker ascends and descends, and includes an internal inertial brake that locks the spool when its play-out speed is indicative of a fall. While~this system can work, the significant forces that can be generated in the event of a fall necessitate that the boom be of relatively robust construction, particularly in consideration of its cantilevered nature. This tends to add either to the weight of the boom (if robust conventional materials are used for construction thereof) or the cost of the boom (if exotic or engineered materials are used for construction thereof). Added weight is problematic from an installation standpoint, since it is advantageous in scaffold construction for the individual parts to be easily handled without the need for cranes or the like.
Added cost is preferably avoided. Among other reasons, scaffolding is often left in an unsecured fashion at construction sites; any individual costly component thereof would be attractive to thieves.

SUMMARY OF THE INVENTION

[0003] A relatively lightweight and relatively inexpensive anchoring device, for use with a lanyard and with a scaffold having vertically-spaced portions including an upper portion and a lower portion, forms one aspect of the present invention.

[0004] This device comprises a substantially rigid arm having a pair of longitudinally-spaced end portions and an intermediate portion, the latter defining a transverse axis. An elongate tensile member is also provided, as is pivot means for mounting the arm to the upper portion of the scaffold in use such that the transverse axis of the arm is disposed substantially horizontally and such that the arm is pivotable about the transverse axis. Further provided is a limit means for defining, in use, an operative orientation of the arm, and for limiting pivotal movement of the arm such that, at the operative orientation, one of the end portions of the arm cannot be pivoted lower.
Means for connecting the tensile member to span, in use, between said one end portion of the arm and the lower portion of the scaffold, to secure the arm at its operative orientation is additionally provided, as is means for securely connecting the lanyard to the other end portion of the arm in use.

[0005] A relatively lightweight and relatively inexpensive anchoring device, for use with a retractable lanyard and with a scaffold, the scaffold being of the type having a rigid frame including a plurality of tubular uprights, forms another aspect of the present invention.

[0006] This device comprises a substantially rigid arm having a pair of longitudinally-spaced end portions and an intermediate portion, the latter defining a transverse axis. Also provided is an elongate tensile member and pivot means for mounting the arm to an upper end of a respective upright in use such that the transverse axis of the arm is disposed substantially horizontally and such that the arm is pivotable about the transverse axis. Further provided is a limit means for defining, in use, an operative orientation of the arm, and for limiting pivotal movement of the arm such that, at the operative orientation, one of the end portions of the arm cannot be pivoted lower. Means for connecting the tensile member to span, in use, between said one end portion of the arm and.a lower portion of said respective upright, to secure the arm at its operative orientation is additionally provided, as is means for securely connecting the lanyard to the other end portion of the arm in use.

[0007] A scaffold assembly capable of construction using relatively lightweight and relatively inexpensive components and for use with a retractable lanyard forms another aspect of the invention. The assembly comprises a scaffold including a plurality of tubular uprights. The assembly also comprises an anchoring device. This device comprises a substantially rigid arm having a pair of longitudinally-spaced end portions and an intermediate portion, the latter defining a transverse axis. Also provided is an elongate tensile member and pivot means for mounting the arm to an upper end of a respective upright such that the transverse axis of the arm is disposed substantially horizontally and such that the arm is pivotable about the transverse axis.
Further provided is a limit means for defining an operative orientation of the arm, and for limiting pivotal movement of the arm such that, at the operative orientation, one of the end portions of the arm cannot be pivoted lower. Means for connecting the tensile member to span between said one end portion of the arm and a lower portion of said respective upright, to secure the arm at its operative orientation is additionally provided, as is means for securely connecting the lanyard to the other end portion of the arm in use.
_3_ (0008] Advantages, features and characteristics of the present invention, as well as methods of operation and functions of the related elements of the structure, and the combination of parts and economies of manufacture, will become more apparent upon consideration of the following detailed description and the appended claims with reference to the accompanying drawings, the latter of which is briefly described hereinafter.
BRIEF DESCRIPTION OF THE DRAWINGS

[0009] FIGURE 1 is a perspective schematic view of a worker scaling a scaffold assembly constructed according to a first preferred embodiment of the present invention;

[0010] FIGURE 2 is a left side view of the scaffold assembly of FIGURE 1;

(0011] FIGURE 3 is a front view of the scaffold assembly of FIGURE 1;

[0012] FIGURE 4 is a top plan view of the scaffold assembly of FIGURE 1;

(0013] FIGURE 5 is a face view of a portion of the assembly of FIGURE 1;

[0014] FIGURE 6 is an end view of the structure of FIGURE 5;

(0015] FIGURE 7 is a view similar to FIGURE 2, showing a scaffold assembly according to a second preferred embodiment of the present invention; and [0016] FIGURE 8 is a view similar to FIGURE 3, of the structure of FIGURE 7.

DETAILED DESCRIPTION

(0017] With general reference to FIGURE 1, a worker 20 is shown using a retractable lanyard 22 to safely scale a scaffold assembly 24 which forms a preferred embodiment of the present invention.

(0018] The assembly 24 comprises a scaffold 2fi and an anchoring device 28.

(0019] The scaffold 26 of this preferred embodiment is constructed of modular scaffolding of the type sold by Wilhelm Layher GmbH 8~ Co. KG. under the trade-mark ALLROUND. With general reference to FIGURES 1-3, the scaffolding will be seen to be assembled into a rigid frame including a working platform or lift 30 supported at its corners by a plurality of tubular uprights or standards, specifically, four tubular uprights 32,32'. The uprights 32,32' extend 8' above the working platform 30, and horizontal tubing 34 boxes in the top of the uprights 32,32' within 8" of their top ends.
A pair of vertically-spaced handrails 36 surround the lift 30. The lower handrail 36 is within 20" of the platform 30. Diagonal bracing 38,38' is affixed on all four sides of the scaffold 26 every 6'8". (In FIGURES 2,3, diagonal bracing 38 to the rear of the frame is shown in phantom outline.) As shown in FIGURES 2-3, on the top 10' of the scaffold 26, al!
diagonal members 38,38' are tied into every horizontal tube that runs across that member. As will also be noted, two of the diagonal members 38' run from about the level of the lift 30 to a point adjacent the upper end of a respective one 32' of the uprights. Generally, the scaffold 26 is square and plum.

[0020] As best seen in FIGURES 1, 5 and 6, the anchoring device 28 includes an arm 40, a stop member 42 and pivot means.

(0021] The arm 40 is substantially rigid and has a pair of longitudinally-spaced end portions 46,46' and an intermediate portion 48. The intermediate portion 48 has a transverse bore 50 extending therethrough coincident with and defining a transverse axis A-A. ' [0022] The stop member 42 is disposed beneath the arm 40 in overlying, abutting relation upon the upper end of the respective upright 32'.

[0023] The pivot means is for mounting the arm 40 to an upper portion of the scaffold 26, specifically, the upper end of the respective upright 32' such that the transverse axis A-A of the arm 40 is disposed substantially horizontally and such that the arm 40 is pivotable about the transverse axis A-A. In this preferred embodiment, the pivot means comprises: a pivot pin 52 which extends through the bore 50 to support the arm 40 for said pivotal movement; a pair of support plates 54 supporting the pivot pin 52 and rigidly connected to stop member 42; and a bar 56 rigidly extending from the stop member 42 into the upper end of the respective upright 32' in use, thereby to stabilize the stop member 42. It will be noted that the stop member 42 lies in the pivot path of the arm 40, thereby to circumscribe such pivotal movement. Thus, the stop member 42 defines a limit means, which defines an operative orientation of the arm 40, and arrests pivots! movement of arm 40 such that, at the operative orientation, which is substantially horizontal, one 46' of the end portions 46,46' of the arm 40 cannot be pivoted lower.

[0024] For weight-saving reasons, the arm 40, the bar 56, the pivot pin 52, the support plates 54 and the stop member 42 are all constructed out of aluminum, and welded to one another [0025] With general reference to FIGURES 1-3, the anchoring device 28 also comprises an elongate tensile member 58. In this preferred embodiment, the tensile member 58 comprises a cable, speci0caliy, a 3/8" wire rope of the type sold by The Crosby Group Inc. of Tulsa, Oklahoma, with its ends fixed into loops using 3/8" Crosby wire rope clips (3 afieach end).

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[0025] The anchoring device 28 also comprises means for connecting the tensile member 58 to span between said one end portion 46' of the arm 40 and a lower portion of the scaffold 26, to secure the arm 40 at its operative orientation. The means for connecting the tensile member 58 comprises a bolt clamp 60, a pair of tensile-member receiving lugs 62 and a pair of % ton shackles 64. The bolt clamp 60 is securely engaged to a lower portion of the respective upright 32', vertically intermediate the lower handrail 36 and the lift 30. The tensile-member-receiving lugs 62 are of aluminum and are respectively secured by welding to the bolt clamp 60 and to said one end portion 46' of the arm 40. The shackles 64 couple the looped ends of the tensile member 58 to the lugs 62.
[0027] The anchoring device 28 additionally comprises means for securely connecting the retractable lanyard 22 to the other end portion 46 of the arm 40 in use;
in this embodiment, an aluminum lanyard-receiving lug 66 is securely connected to the other end portion 46 of the arm 40 by welding to provide such functionality.
[0028 1n use, the free end of the webbing or cable 70 of the lanyard 22 will typically have a string secured thereto (not shown) which extends to the foot of the scaffold 26 when the webbing 70 is fully retracted. Prior to ascent of the scaffold 26, the climber 20 dons a safety harness or belt 68, uses the string to draw down the end of the webbing 70, and ties up (hereto. As the climber 20 ascends, the internal spring bias of the lanyard 22 takes up the slack in the webbing 70. Representative use of the invention is shown in FIGURE 7. When the climber 20 reaches his or her intended destination on the scaffold 26, he or she tie offs to a convenient handrail 36 with a fixed length lanyard (not shown), and disconnects the retractable lanyard 22, whereupon it spools the webbing up and out of the way for subsequent reuse when desired.

(0029] Whereas the foregoing description makes specific reference to scaffolding of the type sold by Wiihelm Layher GmbH & Co. KG. under the trade-mark ALLROUND, it should be understood that scaffolding of other designs may be utilized with equal utility, with modification that will be routine to persons of ordinary skill in the art.
(0030] For example, a second preferred embodiment is shown in FIGURES 7,8, in which scaffolding of the tube and clamp type is utilized. In this case, it will be evident that the side of the scaffold that holds the ladder has a second horizontal tube 72 running just below the top tube to a maximum of 10". Otherwise, the construction is as discussed above, and as such, is not discussed herein ire detail.
[0031] Finally, it is to be understood that while but two embodiments of the present invention have been herein shown and described, it wile be understood that various changes in size, shape and construction of parts may be made without departing from the spirit or scope of the invention.
[0032] For example, whereas the tensile member of the preferred embodiment is a wire rope, the tensile member could be constructed of webbing or tubing.
[0033] Also, whereas in the embodiments illustrated, the pin passes through the arm, it is possible for the arm to be provided with pin projections, in which case, bores for the pin projections could be provided in the support members. Other pivot mechanisms could also be employed.
(0034] As well, whereas the scaffolds disclosed herein include only a single lift, it is known that scaffolds of greater height can be utilized. Where the arm installation height is greater than two 8'0" lifts, it is believed that the scaffold structure will require lateral tie-ins to a building or the like at every 2nd lift. Tie-ins are also believed to be required for any scaffold wherein the ratio of height to base exceeds 3, or which has footprint dimensions smaller than T x T.
_g_ [0035] The inventor is aware that the system can support an arresting force of 5000 Ibs (the equivalent of a 310 Ib man falling 1.$ metres with a 2:1 safety factor) at arm installation heights up to 32'. !t is noted that, even if the tensile member were to break, the fall of the worker would be arrested by the arm.
[0036] Further, whereas lugs are provided on the arm to receive the tensile member and the retractable lanyard, this is not necessary. For example, the arm could simply be bored at its ends to receive the tensile member and lanyard.
Additionally, the arm and attached components could be constructed out of material other than aluminum.
[0037] Yet further, it is expressly contemplated that a stop member could be omitted, such that the range of pivotal movement of the arm would be limited only by the tensile member. However, as indicated, this arrangement is not currently preferred, since it is perceived, inter alia, that it could result in an unpleasant rocking motion of the arm during movement of the worker.
[0038] Finally, and without limitation, it is noted that in the figures, the operative orientation of the arm is substantially horizontal. This need not strictly be the case.
Arrangements wherein the arm was arrested by the tensile member at a somewhat skewed position should work satisfactorily, provided the length of the arm was such that its end projected somewhat laterally beyond the scaffold, such that the worker would not impact on the scaffold in a fall.
[0039] Accordingly, the scope of the invention should be understood as limited only by the claims appended hereto, purposively construed.
_g_

Claims (20)

1. An anchoring device for use with a scaffold and a lanyard, the scaffold having vertically-spaced portions including an upper portion and a lower portion, said device comprising:
a substantially rigid arm, the arm having a pair of longitudinally-spaced end portions and an intermediate portion, the latter defining a transverse axis;
an elongate tensile member;
pivot means for mounting the arm to the upper portion of the scaffold in use such that the transverse axis of the arm is disposed substantially horizontally and such that the arm is pivotable about the transverse axis;
limit means for defining, in use, an operative orientation of the arm, and for limiting pivotal movement of the arm such that, at the operative orientation, one of the end portions of the arm cannot be pivoted lower;
means for connecting the tensile member to span, in use, between said one end portion of the arm and the lower portion of the scaffold, to secure the arm at its operative orientation; and means for securely connecting the lanyard to the other end portion of the arm in use.

2. An anchoring device according to claim 1, wherein the tensile member comprises a cable.

3. An anchoring device according to claim 1, wherein the limit means comprises a stop member disposed beneath the arm in use.

4. An anchoring device according to claim 3, wherein the arm has a bore extending therethrough coincident with the transverse axis and wherein the pivot means comprises:
a pivot pin which extends through the bore to support the arm for said pivotal movement; and a pair of support plates supporting the pivot pin and rigidly connected to the stop member.

5. An anchoring device according to claim 1, wherein the means for connecting the tensile member comprises:
a clamp adapted to securely engage the lower portion of the scaffold; and a pair of tensile-member-receiving lugs respectively secured to the clamp and to said one end portion of the arm.

6. An anchoring device according to claim 1, wherein the means for securely connecting the lanyard comprises a lanyard-receiving lug securely connected to the other end portion of the arm.

7. An anchoring device for use with a retractable lanyard and with a scaffold of the type having a rigid frame including a plurality of tubular uprights, said device comprising:
a substantially rigid arm, the arm having a pair of longitudinally-spaced end portions and an intermediate portion, the latter defining a transverse axis;
an elongate tensile member;
pivot means for mounting the arm to an upper end of a respective upright in use such that the transverse axis of the arm is disposed substantially horizontally and such that the arm is pivotable about the transverse axis;
limit means for defining, in use, an operative orientation of the arm, and for limiting pivotal movement of the arm such that, at the operative orientation, one of the end portions of the arm cannot be pivoted lower;
means for connecting the tensile member to span, in use, between said one end portion of the arm and a lower portion of said respective upright, to secure the arm at its operative orientation; and means for securely connecting the lanyard to the other end portion of the arm.

8. An anchoring device according to claim 7, wherein the limit means comprises a stop member disposed beneath the arm in use.

9. An anchoring device according to claim 8, wherein the pivot means comprises a bar rigidly extending from the stop member into the upper end of said respective upright in use, thereby to stabilize the stop member.

10. An anchoring device according to claim 9, wherein the arm has a bore extending therethrough coincident with the transverse axis and wherein the pivot means further comprises:
a pivot pin which extends through the bore to support the arm for said pivotal movement; and a pair of support plates supporting the pivot pin and rigidly connected to the stop member.

11. An anchoring device according to claim 7, wherein the means for connecting the tensile member comprises:
a tube clamp adapted to securely engage the lower portion of the respective upright; and a pair of tensile-member-receiving lugs respectively secured to the tube clamp and to said one end portion of the arm.

12. A scaffold structure and retractable lanyard anchor assembly, for use with a retractable lanyard, said assembly comprising:
a scaffold including a plurality of tubular uprights;
an anchoring device comprising:
a substantially rigid arm, the arm having a pair of longitudinally-spaced end portions and an intermediate portion, the latter defining a transverse axis;
an elongate tensile member;

pivot means for mounting the arm to an upper end of a respective upright such that the transverse axis of the arm is disposed substantially horizontally and such that the arm is pivotable about the transverse axis;
limit means for defining an operative orientation of the arm, and for limiting pivotal movement of the arm such that, at the operative orientation, one of the end portions of the arm cannot be pivoted lower;
means for connecting the tensile member to span between said one end portion of the arm and a lower portion of said respective upright, to secure the arm at its operative orientation; and means for securely connecting the lanyard to the other end portion of the arm in use.

13. An assembly according to claim 12, wherein the limit means comprises a stop member disposed in overlying, abutting relation upon the upper end of the respective upright.

14. An assembly according to claim 13, wherein the pivot means comprises a bar rigidly extending from the stop member into the upper end of said respective upright in use, thereby to stabilize the stop member.

15. An assembly according to claim 14, wherein the arm has a bore extending therethrough coincident with the transverse axis and wherein the pivot means further comprises:
a pivot pin which extends through the bore to support the arm for said pivotal movement; and a pair of support plates supporting the pivot pin and rigidly connected to the stop member.

16. An assembly according to claim 12, wherein the tensile member is a cable, and wherein the cable is connected to the scaffold and the arm by:
a bolt clamp securely engaged to the lower portion of the respective upright;
and a pair of tensile-member-receiving lugs respectively secured to the tube clamp and to said one end portion of the arm.

17. An assembly according to claim 16, wherein the scaffolding is a parallelepiped frame including at least one interior lift and a surrounding handrail.

18. An assembly according to claim 17, wherein the tube clamp is secured to the upright vertically intermediate the handrail and the lift.

19. An assembly according to claim 12, wherein the scaffolding is modular scaffolding.

20. An assembly according to claim 12, wherein the scaffolding is of the tube and clamp type.