Stabilization of Multi-Purpose Scaffold

Stabilization components are described for use with a lightweight scaffold comprising two ladder frames, an adjustable platform supported between the two ladder frames, and casters. Each ladder frames include two vertical supports connected by cross members. The platform comprises two side rails having guide channels at each end thereof that slide along the vertical supports. The casters includes stems that insert into the lower ends of the vertical supports. When installed, the stabilization components reduce shaking and swaying of the lightweight scaffold.

TECHNICAL FIELD

The present disclosure relates generally to scaffolding and, more particularly, to components used for stabilizing a scaffold during use.

BACKGROUND

Lightweight scaffolds made from metal tubing are commercially available for use when working close to the ground. One such scaffold comprises an adjustable platform supported between two ladder frames. The platform includes guide channels at each end that slide up and down along the vertical supports of the ladder frames. Casters insert into the lower ends of the vertical supports so that the scaffold can roll on the floor or other support surface. Also, the scaffolds are configured to be stacked vertically.

While lightweight scaffolds provide a low cost alternative to more heavy duty scaffolding when working close to the ground, such lightweight scaffolds lack the stability of more heavy duty scaffolds, particularly when the adjustable platform is raised high or when the scaffolds are stacked vertically. The lack of stability is due to excess play between components of the scaffold, lack of reinforcing, and the lightweight material used. Accordingly, there is a need for ways to improve the stability of commonly used lightweight scaffolds.

SUMMARY

The present disclosure relates to stabilization of lightweight scaffolds that are readily available commercially. In the exemplary embodiments, the stabilization components are configured for use with a scaffold comprising two ladder frames, an adjustable platform supported between the two ladder frames, and casters. Each ladder frame includes two vertical supports connected by cross members. The platform comprises two side rails having guide channels at each end thereof that slide along the vertical supports. The casters includes stems that insert into the lower ends of the vertical supports.

According to one aspect of the disclosure, a clamping collar is provided to stabilize the connection between the vertical supports of the scaffold and the casters. The caster includes a wheel connected to a stem that inserts into the lower end of a vertical support. A clamping collar surrounds the lower end of the vertical support and includes a threaded screw that, when tightened, extends through an opening in the vertical support and presses the stem of the caster against the inner wall of the vertical support to remove play between the stem of the caster and the vertical support.

According to another aspect of the disclosure, a clamp is provided to stabilize the connections between the adjustable platform and the vertical supports of the ladder frames. The clamp comprises a C-shaped member, a pressure plate disposed inside the C-shaped member, and a threaded screw that threadably engages the C-shaped member and connects to the pressure late. The C-shaped member is configured to fit around the guide channels on the adjustable platform with the pressure plate oriented to engage the vertical support. When the threaded screw is tightened, the pressure plate presses the vertical support downward into the guide channel and against the back wall of the guide channel.

According to another aspect of the disclosure, one or more braces are provided to stabilize the scaffold when the platform is raised high or when two or more scaffolds are stacked. Each brace extends between respective one of the vertical supports and a respective side rail of the platform to prevent racking motion of the scaffold. The brace may include a clamp for engaging with the vertical support. The clamp comprises a channel, a pressure plate disposed within the channel, a bolt threadably engaged with the clamp. The channel is configured to fit around the corresponding vertical support. The pressure plate is configured to press the corresponding vertical support into an interior wall of the clamp, while the bolt, when tightened, presses the pressure plate into the corresponding vertical support.

The clamping collar, clamps and braces can be used separately or in combination to stabilize the lightweight scaffold.

DETAILED DESCRIPTION

Referring now to the drawings,FIG. 1illustrates a multi-purpose scaffold10according to an exemplary embodiment. The multi-purpose scaffold10comprises two ladder frames12and a platform20supported between the two ladder frames12. The height of the platform20is adjustable.

Each ladder frame12comprises two vertical supports14connected by two or more cross members16. The vertical supports14and cross members16are preferably made of a metal tubing or other tubular material. The cross members16are preferably welded at each end to respective ones of the vertical supports14so that each ladder frame12is a unitary structure. A series of openings18are formed in the vertical supports14and are spaced 2 inches apart. As will be hereinafter described in more detail, the openings18are engaged by a releasable locking mechanism30on the platform20to secure the platform20at a desired height between the ladder frames12.

The platform20comprises two side rails22that extend between the ladder frames12and a deck40that is supported by the side rails22. As seen inFIG. 2, the side rails22comprises an upper angle22aand a lower angle22bconnected by a vertical wall22c. The upper angle22adefines a shoulder28on which the deck40rests. The deck40is held in place by security latches42.

The side rails22connect at each end to a C-shaped guide channel24sized to fit around the vertical supports14of the ladder frames12. The guide channels24are configured to slide along the vertical supports14of the ladder frames12at each end of the scaffold10to adjust the height of the platform20. Two openings26are formed in the inner sidewall of each guide channel24near an upper end of the guide channel24. The openings26are spaced to align with the openings18in the vertical supports14of the ladder frame12at preselected heights. The openings26in the guide channels24are engaged by a releasable locking mechanism30on the platform20to secure the platform20at a desired height between the ladder frames12. A third opening28is formed near a lower end of the guide channel24and aligns with an opening18in the vertical support14. A locking pin29passes through aligned opening28and18in the guide channel24and vertical support14respectively to lock to the guide channel24in place. The locking pin29thus provides additional safety in case the locking mechanism30inadvertently disengages. Diagonal braces25connect a lower end of each guide channel24to the side rail22.

Each guide channel24includes a releasable locking mechanism30for locking the platform20at a desired height. In one embodiment, the releasable locking mechanism30comprises a U-shaped locking pin32that engages with the aligned openings26and18in the guide channel24and vertical supports14respectively to lock the side rail22at a desired height. Each locking pin32includes a pair of spaced apart legs32aconnected by a cross member32b. An L-shaped bracket34supports the locking pin32. The L-shaped bracket34includes a pair of openings36through which the legs32aof the locking pin32extend. Springs38surrounding each leg32aof the locking pin32bias the locking pin32to a locked position. The springs38are compressed when the locking pin32is pulled back to disengage the locking pin36and push the locking pin32back to an engaged position when the locking pin32is released.

In some embodiments, the scaffold10includes casters50disposed at the lower end of each vertical support14. Each caster50includes a stem52that extends into the lower end of a vertical support14as shown inFIG. 3. The stem52of the caster50includes an opening54that is located to align with an opening18in the vertical support14when the stem52of the caster50is inserted into the vertical support14. The stem52is sufficiently long to overlap at least two openings18in the lower end of the vertical support14. A locking pin56passes through aligned opening54and18in the caster50and vertical support14respectively to secure the caster50to the vertical support14.

In some embodiments, the scaffold10as herein described includes a set of compression collars100to remove any play that may exist between the stems52of the casters50and the vertical supports14as shown inFIGS. 4-6. The compression collar100is similar (in a geometrical sense) in shape to the vertical supports14and is sized to fit around and slide over the lower end of a vertical support14. The collar100includes an opening102that is aligned during use with one of the openings18in the vertical support14. A nut106aligned with the opening102is welded to the outer surface of the collar100. A bolt104is threadably engaged with the nut106on the collar100. When tightened, the end of the threaded bolt104contacts the stem52of the caster50and presses the stem52of the caster50against the inner wall of the vertical support14to remove play between the stem52of the caster50and the inner wall of the vertical support14.

In some embodiments, the caster50can be replaced by a footpad (not shown) or other ground-engaging member comprising a generally flat pad that contacts the ground or underlying surface and a stem that extends into that extends into the lower end of a vertical support14. The footpad can be secured using the compression collar100in the same manner as the caster50.

In some embodiments, the scaffold10further comprises a set of clamps110designed to stabilize the connections between the guide channels24and vertical supports as shown inFIGS. 7-9. The clamps110comprise a C-shaped channel112comprising flanges114connected by a central member116. One of the flanges114includes an opening118. A nut124aligned with the opening118is welded to the outer surface of the flange114. A bolt120is threadably engaged with the nut124on the flange114. A pressure plate122is connected to the end of the bolt120. The pressure plate122may be fixedly attached or pivotally attached (e.g., via a ball joint) to the end of the bolt120.

In use, the C-shaped channel112of the clamp110is placed around a guide channel24on the adjustable platform20with the pressure plate122on the open side of the guide channel24. When the bolt120is tightened, the pressure plate122engages the vertical support14and presses the vertical support14downward into the guide channel24and against the back wall of the guide channel24.

In some embodiments, the scaffold10further comprises four auxiliary braces130to prevent relative movement between the ladder frames12and platform due to play between the guide channels24and vertical supports14as shown inFIGS. 10 and 11. In one embodiments, each brace comprises a tubular rod132having flanges134at each end that are bent at an 45 degree angle approximately relative to longitudinal axis of the rod132. Each brace130extends at a 45 degree angle between a respective one of the vertical supports14and a side rail22. The flanges134include openings136for securing the auxiliary brace130to the side rail22and vertical support134respectively. The ends of the auxiliary brace130are secured by conventional bolts138and nuts140. In particular, the opening136in the flange134at one end of the auxiliary brace130aligns with one of the openings18in a vertical supports14. The bolt138passes through the aligned openings18and136in the vertical supports14and flange134respectively and is secured by tightening the nut140. The opening136in the flange134at the other end of the auxiliary brace130aligns with an opening (not shown) in the side rail22. The bolt138passes through the aligned openings in the side rail22and flange134respectively and is secured by tightening the nut140.

When the auxiliary brace130is installed, adjustment in the height of the platform20is prevented. In some embodiments, the bolt138and nut140at the lower end of each brace130can be replaced by a quick connect coupling so that the braces130can be quickly connected and disconnected to adjust the height of the platform20.

FIG. 12illustrates the multi-purpose scaffold10configured according to another embodiment of the present disclosure. As in the previous embodiments, the multi-purpose scaffold10comprises two ladder frames12, each comprising two vertical supports14connected by two or more cross members16, and an adjustable platform20supported between the two ladder frames12. Openings18are formed in the vertical supports14and are spaced 2 inches apart. As previously described, the openings18are engaged by the releasable locking mechanism30on platform20to secure the platform20at a desired height between the ladder frames12.

In this embodiment, multi-purpose scaffold10also comprises one or more stabilizer braces150to prevent movement of the ladder frames12relative to platform20. The stabilizer brace150is similar to the auxiliary brace130in that each stabilizer brace150also comprises a rigid, elongated support body, such as a tubular rod152, having flanges154,156at each terminal end of rod152. The flanges154,156are bent at a 45 degree angle approximately relative to a longitudinal axis of the rod152. Each stabilizer brace150extends at a 45 degree angle between a respective one of the vertical supports14and a side rail22.

One end of the stabilizer brace150is secured to the scaffold10using mechanical fasteners158, such as a conventional bolt and nut. In particular, an opening (not shown but similar to opening136inFIG. 10) is formed in flange154that aligns with an opening (not shown) formed in side rail22. The bolt passes through the aligned openings in the flange154and side rail22, respectively, and is secured by tightening the nut.

Flange156, however, is not connected to vertical support14using a conventional nuts and bolts. Rather, flange156is fixedly attached to a clamp160that, in turn, is removably attached to a vertical support14. In particular, as seen in the embodiment ofFIG. 13, flange156is welded to an exterior surface of a wall162of clamp160, although other methods of fixedly attaching the flange156are also possible. Clamp160fits around vertical support14and comprises a handle164configured to move back and forth through a receiver166. The handle164is also configured to rotate in both clockwise and counterclockwise directions so as to tighten and loosen the clamp160from vertical support14.

FIGS. 14-15illustrate how clamp160is removably connected to vertical support14according to one embodiment. As seen in these figures, the wall162of clamp160forms a channel174that fits around the vertical support14. Clamp160further comprises a pressure plate168pivotably attached to a bolt172via a pivot member170. In this embodiment, the pivot member170comprises a ball joint movably connecting the pressure plate168to the bolt172.

The bolt172extends through the wall162and is attached to a receiver166. In one embodiment, bolt172is threadably attached to the wall162. In other embodiments, however, bolt172threadably attaches to a nut176that is fixedly attached to wall162. In any case, bolt172is attached to receiver166such that when a user rotates handle164, the bolt172also rotates to move the pressure plate168towards and away from vertical support14.

In use, the channel174of clamp160is placed around a vertical support14. Rotating the handle164in the clockwise direction also rotates the bolt172, thereby causing pressure plate168to move towards, and engage, the vertical support14. Continued rotation of handle164causes the pressure plate168to press vertical support14against an interior surface178of wall162. Rotating the handle164in the counterclockwise direction, however, also rotates bolt172thereby causing pressure plate168to move away from the vertical support14. This movement releases the vertical support14from its pressing engagement against the back interior surface178of wall162, thereby loosening the clamp160from vertical support14.

It should be noted that handle164, while facilitating the rotation of bolt172, is not needed. In some embodiments, such as the one seen inFIG. 15, for example, the handle164and receiver166are not present. Instead, only the bolt172exists. Regardless, rotating the bolt172clockwise and counter clockwise causes the pressure plate168to move towards and away from vertical support14, as previously described.

When the stabilizer brace150is installed, adjustment in the height of the platform20is prevented and the stability of the multi-purpose scaffold10is greatly enhanced. This is especially true when a plurality of stabilizer braces150are installed.FIG. 16, for example, illustrates an embodiment where four stabilizer braces150are installed. Further, because of its design, the stabilizer brace150is easily connected and disconnected from the multi-purpose scaffold10.

The stabilization components as herein described remove excess play between components of the scaffold and prevent racking to provide greater stability. The increased stability enhances worker's confidence when standing on the scaffold.