US3373844A - Compact motorized scaffold arrangement - Google Patents

Description

March 19, 1968' G. F. SCHAFER COMPACT MOTORIZED SCAFFOLD ARRANGEMENT Filed May 16, 1966 INVENTOR.

"Gm/m5 E SdHAFER United States Patent 3,373,844 COMPACT MOTORIZED SCAFFOLD ARRANGEMENT George F. Schafer, El Tahoe, Calif. (R0. Box AV-Bijou, Lake Tahoe, Calif.) Filed May 16,- 1966, Ser. No. 550,275 1 Claim. (Cl. 182-141) ABSTRACT OF THE DISCLOSURE This invention relates to a lazy tong scaffolding assembly having spaced lazy tong side portions with transversely extending tie rods for stabilizing the assemblies together with an additional lazy tong assembly mounted upon the spacing tie rods and operating in a plane perpendicular to the spaced lazy tong assemblies as a stabilizing means and a cable retracting means in the form of a bobbin over which the lazy tong extending cable is wound with superimposed concentric turns to provide a maximum torque during the initial lazy tong extending operation.

My present invention relates to a scaffold forming device and more particularly to a mechanized self-contained scaffolding assembly of lazy tong construction.

An object of the invention is to provide a novel and practical scaffold forming device of novel and collapsible construction employing lazy tong assemblies which may be moved about and used adjacent a structure without requiring any stabilizing attachment with the structure.

Another object of the invention is to provide a scaffolding arrangement employing a lazy tong assembly having means by which the assembly is extended and retained by forces applied at several points through cable connections in a novel, practical and efiicient manner.

A further object of the invention is to provide a scaffolding employing spaced lazy tong assemblies mounted upon a supporting platform having cable retrieving drums for each of said lazy tong assemblies and a cable interlaced and extending about pulleys at the ends of each of the pivotally mounted bars of said lazy tong assembly and attached at its outer end to one of the uppermost of the lazy tong forming bars, whereby said cable will operate to apply an extending force for each pair of the cross bars of the lazy tong assembly.

Another object of the invention is to provide a lazy tong scaffold forming arrangement having parallel lazy tong forming bars connected at their crossed points by a transversely extending cylindrical shaft with additional lazy tong assembly extending at a right angle to the planes of said parallel lazy tong bars having crossed links secured along one side upon said transversely extending shafts and the other sides thereof being connected to a slidably mounted collar upon said spaced shafts, whereby said spaced parallel lazy tong assemblies will be held in stabilized vertically spaced relationship when extended.

Other objects and advantages will be in part evident to those skilled in the art and in part pointed out hereinafter in the following description taken in connection with the accompanying drawing, wherein there is shown by way of illustration and not of limitation a preferred embodiment of the invention.

In the drawing:

FIGURE 1 is a side elevation of my scaffolding in an extended condition,

FIGURE 2 is an end view of the scaffolding as shown in FIGURE 1,

FIGURE 3 is a fragmentary view showing portions of the scaffolding of FIGURE 1 in a collapsed condition, and,

3,373,844 Patented Mar. 19, 1968 "ice FIGURE 4 is a fragmentary view showing a detail of the assembly.

Reference is now made to the accompanying drawing for a more detailed description of the invention and wherein the numeral designates generally a supporting frame or base having casters 11 by which the base may be moved from one point to another. At one end of the v base 10, there are two laterally spaced pivot forming bearings 12 and at the other extreme end the base 10 there are longitudinally extending guide rails 13 for rollers 14 carried by each of the two laterally spaced lazy tong assemblies. The lazy tong assemblies as here shown in FIGURE 1 consist of a lower pair of crossed bars 15 and 16 mounted upon tie rods 17 at their crossing points.

The cross bars 16 are pivotally mounted at their lower ends upon the pivotal bearings 12 and the cross bars 15 carry the rollers 14 at their lower ends which ride upon the rails 13. Superimposed upon the crossed bars 15 and '16, there is an additional set of crossed bars 18 and 19 that are likewise pivotally mounted upon an additional transverse tie rod 17. The cross bar 18 is pivotally connected at its lower end to the upper end of the cross bar 16 of the lower assembly and the lower end of the cross bar 19 is similarly pivotally connected to the upper end of the cross bar 15. Similar crossed bars 20 and 21 that are pivotally mounted upon the transversely extending tie rods 17 are pivotally connected at their lower ends respectively to the upper ends of the crossed bars 18 and 19, there being in this showing three sets of crossed bars, which, when connected as above, will form lazy tong assemblies extending vertically in spaced parallel relation above the sides of the supporting base '10. At its upper end the cross bar 21 carries a pivotal mounting for a longitudinally extending platform supporting member 22 and the upper end of the cross bar 20 carries a roller assembly 23 over which the platform supporting member 22 will freely ride as the lazy tong arrangement is extended and retracted. This arrangement is such that the platform supporting member 22 with a planking 24 thereupon will retain a substantially level disposition irrespective of the extension of the lazy tong assemblies. At this point it should be understood that while there are shown only three sets of crossed bars, it is conceivable that any number of similar crossed bars may be added to provide for a greater elevation of the platform 22 with its planking 24. As a means for extending the lazy tong arrangement constructed as above described, the base 10 carries a cable retracting drum 25 from which a cable 26, shown for the sake of clearness in FIGURE lof the drawings by dot and dash lines, is payed out and retrieved. When the lazy tong assembly is extended the cable 26 will pass around a pulley 27 at the lower end of the crossed bar 15 about a pulley 28 at the meeting point of the crossed bars 15 and 19, around a similar pulley 29 at the pivotal point between the crossed bars 16 and 18 and from the pulley 29 the cable passes from the pulley 29 to a pulley 30 and through a horizontal course to a pulley 31 at the meeting ends of the crossed bars 19 and 21. From the pulley 31, the cable passes around a final pulley 32 and to a fixed point 33 at the upper end of the crossed bar 20. With this arrangement, it will be understood that when the cable 26 is retracted by the cable retracting drum 25 a lazy tong extending force will be applied directly at the lower end of the crossed bar 15 and simultaneously in a horizontal direction between the pulleys 28 and 29 and the pulleys 30 and 31 as shown by dot and dash lines. The final lazy tong extending force will then be exerted between the pulley 32 and the fixed point 33 at the upper end of the crossed bar 20. With the cable accommodating pulleys 28 to 31 disposed between the connected ends of the crossed bars 15 to 21, it will be understood that the cable 3 26 will find a free path for movement between these crossed bars to 21, it will be understood that the cable interrupted dot and dash line between these points. The cable retracting drum is also shown as powered through a chain and sprocket drive 34 by an electric motor 35 under the control of a switch 36.

As is more clearly shown in FIGURE 2 of the drawings, the parallel link assemblies above described are held in. spaced and stabilized relation by the tie rods 17 and are also further stabilized by two lazy tong assemblies 37 and 38, each of which consists of three sets of crossed links connected in lazy tong fashion, each of which are secured at their extreme ends and one side at fixed points 39 upon the transverse rods 17 so that these lazy tong assemblies will be held in fixed relation at one end of the stabilizing rods 17. At their other sides and extreme ends these lazy tong assemblies 37 and 38 are connected to collars 40 that are slidably mounted upon each of the transverse rods 17. With this arrangement, it will be seen that as the major lazy tong assemblies consisting of the crossed links 15 to 21 are extended and collapsed these latter lazy tong assemblies 37 and 38 will likewise become extended and collapsed and at the same time they will exert a further stabilizing force between the major lazy tong assemblies. As indicated in the drawing, the innermost links 15, 18 and 21 of the major lazy tong assemblies are reinforced by transverse braces 41, which, for clarity, have been shown in FIGURE 2 as broken away to more clearly expose the inner lazy tong assemblies 37 and 38.

In FIGURE 1 of the drawing, it will be noted that the lazy tong retracting cable 26, instead of passing directly from the cable retracting drum 25 to the pulley 27 carried by the arm 15, is here shown as passing upwardly and over a pulley 44 that is supported in an elevate-d po- 3 sition and in coplanar relation with a pulley 42 at the pivotal point between the lazy tong bars 15 and 16. The purpose of this elevated pulley 44 is to provide for an initial upward lifting force at the pulley 42. This feature becomes operative when, as here indicated by lighter dot and dash lines 26', the pulley 42 is in its lowermost posi tion. To carry out this feature in a more extreme manner, FIGURE 3 shows the base 10 as having a more extended bracket 45 with a pulley 46 which will correspond with the pulley 44 of the FIGURE 1. Therefore, as here shown by heavy dot and dash lines, an initial retraction of the cable 26 upon the drum 15 will exert an upward lifting force upon the pulley 42 carried by the crossed bars 15 and 16.

In order to provide for additional leverage in the retraction of the lazy tong extending cable 26, I have in FIGURE 4 of the drawings shown the cable recoiling drum 25 as in the form of a bobbin with narrowly spaced sides so that the cable 26 will be wound thereupon in overlapping concentric turns. In this manner, when the lazy tong assembly is completely collapsed the cable 26 will be completely payed out from the drum so that upon an initial extension of the lazy tong assembly the first turn of the cable 26 will be closely adjacent to the axis of the drum 25 where the maximum cable retracting force will be required.

With the above description, it is believed that the operation of my invention will be clearly understood, and

while I have, forthe sake of clearness and in order to disclose my invention so that the same can be readily understood, described and illustrated a specific form and arrangement, I desire to have it understood that this invention is not limited to the specific form disclosed, but may be embodied in other ways that will suggest themselves to persons skilled in the art. It is believed that this invention is new and all such changes as come within the scope of the appended claim are to be considered as part of this invention.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

1. In a scaffolding embodying an extendable lazy tong supporting structure, the combination of a supporting base having two spaced longitudinally extending side members, each having a guide rail at one end and pivotal lazy tong supporting bearings at their other ends, a first pair of spaced lazy tong elements having one of the crossed bars thereof pivotally mounted upon said pivotal bearing and the corresponding end of the other of each of said crossed bars having rollers engaging said guide rails, a second set of crossed bars pivotally secured at their lower ends to the upper ends of said first crossed bar assembly, an additional set of similarly crossed bars forming an extension of said lazy tong assembly, a horizontally extending platform member pivotally secured at one end between the cross bars of said last crossed bar, a platform supporting roller between the upper ends of the other of said crossed bars, means for attaching the outer end of a length of cable to said last crossed bars at this point, cable supporting pulleys at the points of con nection between the ends of said cross bars, a cable retracting drum mounted upon said supporting base, a cable extending from its point of connection to the uppermost bars of said lazy tong assembly passing over and around the pulleys at the meeting ends of said crossed bars adapted and arranged to exert a lazy tong extending force between the successive sets of crossed lazy tong forming bars when retracted by said cable retracting drum, characterized by the fact that the crossed bars of each of the lazy tong elements are spaced laterally by a transversely extending tie rod, said tie rod forming a support for lazy tong assemblies operating in a plane at right angles to said pairs of spaced lazy tong forming elements, the extreme ends of said latter lazy tong assemblies being secured at one side to a fixed point upon said transversely extending stabilizing rods and connected at their other extreme ends to collars slidably mounted upon said transversely extending rods, whereby said latter lazy tong assemblies will further operate to stabilize the spaced and parallel relationship between said first and subsequent pairs of spaced lazy tong elements.

References Cited UNITED STATES PATENTS 559,098 4/1896 Davies --319 1,824,673 9/1931 Lee 160319 3,259,369 7/1966 Gridley 182141 FOREIGN PATENTS 124,211 10/1901 Germany.

REINALDO P. MACHADO, Primary Examiner.

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