Title:
LADDER
United States Patent 3762500
Abstract:
A ladder having a horizontal mounting bracket, including a clamping mechanism for securing the ladder to the vertical or horizontal frame members of a scaffold or similar structure, is adjustably mounted to the back of the ladder side rails so the ladder can be easily attached to the scaffold at any desired vertical position. A T-bolt member, slidably disposed in each of the channel-shaped side rails, carries the ends of the bracket. The bracket is clamped in place against the backside of the ladder side rails by tightening a wing nut threaded onto the T-bolt member. The T-bolt head has curved outer ends which engage and become locked against the inside surfaces of the opposite side walls of the channels during initial tightening of the wing nut. This locking action permits the wing nuts to be fastened by one hand, thereby permitting both ends of the bracket to be easily tightened into place simultaneously. The clamping mechanism is swivelably mounted to the mounting bracket so the ladder can be attached to either horizontal or vertical members of the scaffold. The mounting brackets can be easily removed from the ladder by rotating the T-bolts so their heads can be lifted through the elongated openings in the respective side rails.
US Patent References:
Scaffold ladder clamp
Olsen - August 1960 - 2947555
Ladder attachment
Chubbs - April 1962 - 3028929
Ladder platform
Weber - August 1968 - 2848282
Scaffold ladder clamp
Olsen - August 1960 - 2947555
Ladder attachment
Chubbs - April 1962 - 3028929
Ladder platform
Weber - August 1968 - 2848282
Application Number:
05/220195
Publication Date:
10/02/1973
Filing Date:
01/24/1972
View Patent Images:
Export Citation:
Assignee:
A-T-O Inc. (Willoughby, OH)
Primary Class:
Other Classes:
182/206, 182/214
International Classes:
E06C7/48; E06C7/00; E06C9/00
Field of Search:
182/214,93,206
Primary Examiner:
Machado, Reinaldo P.
Claims:
I claim
1. A ladder for a scaffold or the like having vertical and horizontal frame members comprising:
2. A ladder according to claim 1 in which each of said connector assemblies includes a T-shaped member having a cross-leg portion and a longitudinal leg portion, said cross-leg portion adapted for gripping engagement with the sidewalls of said channel side rails at selected vertical points along the vertical length of said side rails, and said longitudinal leg portion extending out through the open side of said channel side rails for removable connection with a leg portion of said bracket member.
3. A ladder according to claim 2 in which said cross-leg portion of said T-shaped members have curved outer ends for locking engagement with the sidewalls of said channel side rails.
4. A ladder according to claim 2 in which said longitudinal leg portion of said T-shaped members are threaded externally to receive an internally threaded retaining member.
5. A ladder according to claim 2 in which said channel side rails have a pair of inturned retaining flanges which serve to block outward movement of said T-shaped members when the cross-leg portions thereof are positioned for gripping engagement with said sidewalls of said channel side rails.
6. A ladder according to claim 5 in which each of said inturned retaining flanges is provided with a seating flange against which one face of said cross-leg portion seats when said cross-leg portions are positioned for gripping engagement with said sidewalls of said channel side rails.
7. A ladder capable of being attached to the frame members of a sectional scaffold having vertical and horizontal frame members comprising:
8. The ladder according to claim 7 wherein
9. The ladder according to claim 4 wherein the width of said plate is less than the width of said opening so that said T-shaped members can be removed through said opening by rotating said plates so the longitudinal axis thereof is substantially parallel with the longitudinal axis of the corresponding of said openings.
1. A ladder for a scaffold or the like having vertical and horizontal frame members comprising:
2. A ladder according to claim 1 in which each of said connector assemblies includes a T-shaped member having a cross-leg portion and a longitudinal leg portion, said cross-leg portion adapted for gripping engagement with the sidewalls of said channel side rails at selected vertical points along the vertical length of said side rails, and said longitudinal leg portion extending out through the open side of said channel side rails for removable connection with a leg portion of said bracket member.
3. A ladder according to claim 2 in which said cross-leg portion of said T-shaped members have curved outer ends for locking engagement with the sidewalls of said channel side rails.
4. A ladder according to claim 2 in which said longitudinal leg portion of said T-shaped members are threaded externally to receive an internally threaded retaining member.
5. A ladder according to claim 2 in which said channel side rails have a pair of inturned retaining flanges which serve to block outward movement of said T-shaped members when the cross-leg portions thereof are positioned for gripping engagement with said sidewalls of said channel side rails.
6. A ladder according to claim 5 in which each of said inturned retaining flanges is provided with a seating flange against which one face of said cross-leg portion seats when said cross-leg portions are positioned for gripping engagement with said sidewalls of said channel side rails.
7. A ladder capable of being attached to the frame members of a sectional scaffold having vertical and horizontal frame members comprising:
8. The ladder according to claim 7 wherein
9. The ladder according to claim 4 wherein the width of said plate is less than the width of said opening so that said T-shaped members can be removed through said opening by rotating said plates so the longitudinal axis thereof is substantially parallel with the longitudinal axis of the corresponding of said openings.
Description:
BACKGROUND OF THE INVENTION
This invention relates to ladders and more particularly to a ladder for use with a sectional scaffold.
Sectional scaffolds are quite widely used in the construction field. A scaffold of this type includes a plurality of end frame sections which have a pair of spaced vertical frame members connected together by two or more horizontal frame members. Typically, these frame members are made from tubular steel in order to obtain maximum structural integrity and minimum weight. Upstanding and spaced apart end sections are connected together by cross bracing members which are removably fastened to the vertical frame members, such as by bolts, so the scaffold can be readily broken down for easy transportation and storage. Scaffold planking extends between end sections and is supported on the horizontal members of the end sections. The scaffolding is built up to the desired height by assembling additional end sections on top of previously installed ones.
Ladders, which can be attached to the frame members of the end sections, are used to enable workmen to readily ascend and descend the scaffold. U.S. Pat. No. 2,125,289 discloses an example of such a ladder. Although reasonably adequate for this purpose, the prior art ladders have several shortcomings. Generally, the frame attachment means is adaptable only to the horizontal members of the end sections and is either fixed to the ladder or can only be adjusted a very limited amount. Consequently, the vertical positioning of the ladder on the scaffold is substantially limited to locations where vertical positions of the attachment means correspond to the horizontal members of the end frame sections. Ladders of this type are typically built in sections so the ladder can be built up along with the scaffold. With little or no vertical adjustment capability, any variation made in the elevation of the various horizontal frame members of the end section makes the installation of the ladder sections very difficult. Also, the protruding attachment means cannot be readily removed from the ladder sections and complicates stacking of the ladder sections for transportation or storage.
SUMMARY OF THE INVENTION
A primary object of this invention is to provide a scaffold ladder with an attachment means which can be adjusted vertically so that the ladder can be easily installed at any desired vertical position on the scaffold.
Another object of this invention is to provide a scaffold ladder which can be attached to either the vertical or horizontal frame members of the scaffold sections and can be attached either to the inside or outside of the scaffold.
A further object of this invention is to provide a scaffold ladder having a scaffold attachment means which can be easily removed to facilitate storage and transportation.
According to this invention, a ladder, having a pair of vertical side rails and a plurality of spaced rungs, is provided with a scaffold mounting bracket which is adjustably mounted to the side rails so it can be lowered up and down the vertical length of the ladder. This permits the ladder to be mounted at any desired vertical position on the scaffold. The mounting beacket includes a means for clamping the ladder to the frame members of the scaffold. Preferably, this clamping means is swivelably mounted to the mounting bracket so that the ladder can be mounted to either horizontal or vertical frame members of the scaffold.
The side rails are preferably channel-shaped with an elongated opening. A T-shaped member, slidably disclosed in each channel, has a longitudinal leg extending through this opening which carries one end of the mounting bracket. This member is provided with means, preferably a wing nut threaded onto the longitudinal leg, for clamping the mounting bracket in place against the backside of the side rails at the desired vertical position. The cross leg of the T-shaped member can be arranged so it becomes locked against the inside walls of the side rail channels during initial tightening of the nut. This arrangement permits each end of the bracket to be rapidly tightened into place with one hand. Hence, both ends of the bracket can be tightened into place simultaneously.
Also, the mounting brackets can be made to be removable from the ladder by arranging the cross leg of the T-shaped member to have a width smaller than the width of the elongated opening in the side rails. These members can then be lifted through their respective openings in the side rails after proper orientation.
DESCRIPTION OF THE DRAWINGS
FIG.1 is a perspective, fragmentary view of two scaffold ladders embodying this invention, one shown attached to a horizontal frame member of a sectional scaffold and the other shown attached to a vertical frame member of a sectional scaffold.
FIG. 2 is a sectioned, plan view taken along the plane designated 2--2 in FIG. 1.
FIG. 3 is a fragmentary, sectional view taken along the plane designated 3--3 in FIG. 2.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Ladder 10 includes a pair of channeled side rails 12, 12, a plurality of uniformly spaced rungs 14 (one shown), welded or otherwise suitably mounted to side rails 12, and a mounting bracket assembly 16 for securing the ladder to the frame members of an end section 18 of a sectional scaffold. Each channel shaped side rail 12 is provided with a pair of inturned retaining flanges 17, 17 having an opening 36 therebetween and each flange 17 has a small seating flange 19 formed along the edge thereof. FIG. 1 shows two ladders, with the ladder on the right attached to a horizontal frame member 20 and the one on the left attached to a vertical frame member 22. The upper ends of each side rail 12 can be provided with coupling members 24 over which the bottom end of the rails of another ladder section can be installed. This arrangement permits the length of the ladder to be extended, as required, during build up of the scaffold. When several ladder sections are used in this manner, the bottom-most section can be provided with two mounting bracket assemblies with one located near the top and the other near the bottom. One mounting bracket assembly located near the top is usually sufficient for the securing of the remaining ladder sections to the scaffold.
Mounting bracket assembly 16 includes a U-shaped bracket 26 having a base portion 27 and a pair of leg portions 29,29 terminating with flat flanges 28, 28 on either end. As best shown in FIGS. 2 and 3 flanges 28 are clamped against the backside of side rails 12 by a wing nut 30 threaded onto a T-bolt, which has a flat plate head 32 disposed inside the side rail channel and a threaded stud 34 extending through elongated opening 36 and an aperture in flange 28. As shown in FIG. 3, the width of bolt head 32 is smaller than the width of opening 36. Bracket 26 is installed on ladder 10 by orienting bolt heads 32 so they fit through opening 36 (as shown by the dashed lines in FIG. 3), and tightening wing nuts 30. Initial tightening of wing nut 30 in the direction of the arrow rotates bolt head 32 until the outer curved ends 38 thereof become wedged against the opposite inside walls of the rail (as shown in solid lines in FIG. 3). This arrangement permits the tightening operation to be easily performed by one hand. Hence, one man can easily tighten both ends of bracket 26 into place simultaneously. Opening 36 extends substantially along the entire length of side rail 12 so that, when wing nuts 30 are loosened, the mounting bracket assembly can be moved vertically along the vertical length of the side rails. Thus, the mounting bracket assembly can be easily positioned in any desired elevation on the ladder. This permits the ladder to be attached to the scaffold frame members in any desired vertical position. The mounting bracket assembly can be easily removed to facilitate stacking of the ladder sections for transportation or storage by simply loosening wing nuts 30 and rotating stud 34 so bolt heads 32 can be lifted through their respective openings 36. Preferably, the outer end of stud 34 is peened, after the wing nut has been threaded on, so the wing nut cannot be completely removed.
Clamp 40 is swivelably mounted to to the outer face of base portion 27 of bracket 26 so the ladder can be mounted either to a horizontal or vertical frame member of scaffold as shown in FIG. 1. Jaws 42, 44 of clamp 40, which are arranged to conform to the outer contour of the scaffold frame members, are hinged together at 46 so they can be opened to fit over the frame member to which the bracket is to be attached. Bolt 48, pivotally attached to jaw 42, extends through a slot provided in shoulder 50 on jaw 44. After the jaws have been positioned over the desired scaffold frame member, the jaws are clamped into engagement with the frame member by tightening nut 52, which is threaded onto bolt 48, to securely attach the ladder to the scaffold. Bracket 26 holds the ladder away from the scaffold frame member a sufficient distance to provide adequate toe room for climbing. As shown in FIG. 1, mounting brackets 26 to be secured to horizontal scaffold frame members can be provided with support brackets 54 which embrace a portion of the frame member to improve stability of the ladder sections. These support brackets prevent the ladder from rocking about the swivel connection of clamp 40. Preferably, the mounting brackets on the ladder sections to be secured to the vertical scaffold frame member do not include these support brackets because of the potential snagging hazard for workmen.
From the above detailed description, it can be seen that the scaffold ladder provided by this invention has considerable versatility. It can be mounted on either vertical or horizontal frame members of the scaffold and can be positioned inside or outside the scaffold. The mounting bracket assembly can be easily and rapidly adjusted so the ladder can be positioned at any desired elevation; even extended above the scaffold planking if desired. The mounting bracket assemblies can be easily removed from the ladder to facilitate transportation and storage of the ladder sections.
As will readily be apparent to those skilled in the art, various modifications and alterations can be made to the preferred embodiment described above without departing from the spirit and scope of the invention.
This invention relates to ladders and more particularly to a ladder for use with a sectional scaffold.
Sectional scaffolds are quite widely used in the construction field. A scaffold of this type includes a plurality of end frame sections which have a pair of spaced vertical frame members connected together by two or more horizontal frame members. Typically, these frame members are made from tubular steel in order to obtain maximum structural integrity and minimum weight. Upstanding and spaced apart end sections are connected together by cross bracing members which are removably fastened to the vertical frame members, such as by bolts, so the scaffold can be readily broken down for easy transportation and storage. Scaffold planking extends between end sections and is supported on the horizontal members of the end sections. The scaffolding is built up to the desired height by assembling additional end sections on top of previously installed ones.
Ladders, which can be attached to the frame members of the end sections, are used to enable workmen to readily ascend and descend the scaffold. U.S. Pat. No. 2,125,289 discloses an example of such a ladder. Although reasonably adequate for this purpose, the prior art ladders have several shortcomings. Generally, the frame attachment means is adaptable only to the horizontal members of the end sections and is either fixed to the ladder or can only be adjusted a very limited amount. Consequently, the vertical positioning of the ladder on the scaffold is substantially limited to locations where vertical positions of the attachment means correspond to the horizontal members of the end frame sections. Ladders of this type are typically built in sections so the ladder can be built up along with the scaffold. With little or no vertical adjustment capability, any variation made in the elevation of the various horizontal frame members of the end section makes the installation of the ladder sections very difficult. Also, the protruding attachment means cannot be readily removed from the ladder sections and complicates stacking of the ladder sections for transportation or storage.
SUMMARY OF THE INVENTION
A primary object of this invention is to provide a scaffold ladder with an attachment means which can be adjusted vertically so that the ladder can be easily installed at any desired vertical position on the scaffold.
Another object of this invention is to provide a scaffold ladder which can be attached to either the vertical or horizontal frame members of the scaffold sections and can be attached either to the inside or outside of the scaffold.
A further object of this invention is to provide a scaffold ladder having a scaffold attachment means which can be easily removed to facilitate storage and transportation.
According to this invention, a ladder, having a pair of vertical side rails and a plurality of spaced rungs, is provided with a scaffold mounting bracket which is adjustably mounted to the side rails so it can be lowered up and down the vertical length of the ladder. This permits the ladder to be mounted at any desired vertical position on the scaffold. The mounting beacket includes a means for clamping the ladder to the frame members of the scaffold. Preferably, this clamping means is swivelably mounted to the mounting bracket so that the ladder can be mounted to either horizontal or vertical frame members of the scaffold.
The side rails are preferably channel-shaped with an elongated opening. A T-shaped member, slidably disclosed in each channel, has a longitudinal leg extending through this opening which carries one end of the mounting bracket. This member is provided with means, preferably a wing nut threaded onto the longitudinal leg, for clamping the mounting bracket in place against the backside of the side rails at the desired vertical position. The cross leg of the T-shaped member can be arranged so it becomes locked against the inside walls of the side rail channels during initial tightening of the nut. This arrangement permits each end of the bracket to be rapidly tightened into place with one hand. Hence, both ends of the bracket can be tightened into place simultaneously.
Also, the mounting brackets can be made to be removable from the ladder by arranging the cross leg of the T-shaped member to have a width smaller than the width of the elongated opening in the side rails. These members can then be lifted through their respective openings in the side rails after proper orientation.
DESCRIPTION OF THE DRAWINGS
FIG.1 is a perspective, fragmentary view of two scaffold ladders embodying this invention, one shown attached to a horizontal frame member of a sectional scaffold and the other shown attached to a vertical frame member of a sectional scaffold.
FIG. 2 is a sectioned, plan view taken along the plane designated 2--2 in FIG. 1.
FIG. 3 is a fragmentary, sectional view taken along the plane designated 3--3 in FIG. 2.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Ladder 10 includes a pair of channeled side rails 12, 12, a plurality of uniformly spaced rungs 14 (one shown), welded or otherwise suitably mounted to side rails 12, and a mounting bracket assembly 16 for securing the ladder to the frame members of an end section 18 of a sectional scaffold. Each channel shaped side rail 12 is provided with a pair of inturned retaining flanges 17, 17 having an opening 36 therebetween and each flange 17 has a small seating flange 19 formed along the edge thereof. FIG. 1 shows two ladders, with the ladder on the right attached to a horizontal frame member 20 and the one on the left attached to a vertical frame member 22. The upper ends of each side rail 12 can be provided with coupling members 24 over which the bottom end of the rails of another ladder section can be installed. This arrangement permits the length of the ladder to be extended, as required, during build up of the scaffold. When several ladder sections are used in this manner, the bottom-most section can be provided with two mounting bracket assemblies with one located near the top and the other near the bottom. One mounting bracket assembly located near the top is usually sufficient for the securing of the remaining ladder sections to the scaffold.
Mounting bracket assembly 16 includes a U-shaped bracket 26 having a base portion 27 and a pair of leg portions 29,29 terminating with flat flanges 28, 28 on either end. As best shown in FIGS. 2 and 3 flanges 28 are clamped against the backside of side rails 12 by a wing nut 30 threaded onto a T-bolt, which has a flat plate head 32 disposed inside the side rail channel and a threaded stud 34 extending through elongated opening 36 and an aperture in flange 28. As shown in FIG. 3, the width of bolt head 32 is smaller than the width of opening 36. Bracket 26 is installed on ladder 10 by orienting bolt heads 32 so they fit through opening 36 (as shown by the dashed lines in FIG. 3), and tightening wing nuts 30. Initial tightening of wing nut 30 in the direction of the arrow rotates bolt head 32 until the outer curved ends 38 thereof become wedged against the opposite inside walls of the rail (as shown in solid lines in FIG. 3). This arrangement permits the tightening operation to be easily performed by one hand. Hence, one man can easily tighten both ends of bracket 26 into place simultaneously. Opening 36 extends substantially along the entire length of side rail 12 so that, when wing nuts 30 are loosened, the mounting bracket assembly can be moved vertically along the vertical length of the side rails. Thus, the mounting bracket assembly can be easily positioned in any desired elevation on the ladder. This permits the ladder to be attached to the scaffold frame members in any desired vertical position. The mounting bracket assembly can be easily removed to facilitate stacking of the ladder sections for transportation or storage by simply loosening wing nuts 30 and rotating stud 34 so bolt heads 32 can be lifted through their respective openings 36. Preferably, the outer end of stud 34 is peened, after the wing nut has been threaded on, so the wing nut cannot be completely removed.
Clamp 40 is swivelably mounted to to the outer face of base portion 27 of bracket 26 so the ladder can be mounted either to a horizontal or vertical frame member of scaffold as shown in FIG. 1. Jaws 42, 44 of clamp 40, which are arranged to conform to the outer contour of the scaffold frame members, are hinged together at 46 so they can be opened to fit over the frame member to which the bracket is to be attached. Bolt 48, pivotally attached to jaw 42, extends through a slot provided in shoulder 50 on jaw 44. After the jaws have been positioned over the desired scaffold frame member, the jaws are clamped into engagement with the frame member by tightening nut 52, which is threaded onto bolt 48, to securely attach the ladder to the scaffold. Bracket 26 holds the ladder away from the scaffold frame member a sufficient distance to provide adequate toe room for climbing. As shown in FIG. 1, mounting brackets 26 to be secured to horizontal scaffold frame members can be provided with support brackets 54 which embrace a portion of the frame member to improve stability of the ladder sections. These support brackets prevent the ladder from rocking about the swivel connection of clamp 40. Preferably, the mounting brackets on the ladder sections to be secured to the vertical scaffold frame member do not include these support brackets because of the potential snagging hazard for workmen.
From the above detailed description, it can be seen that the scaffold ladder provided by this invention has considerable versatility. It can be mounted on either vertical or horizontal frame members of the scaffold and can be positioned inside or outside the scaffold. The mounting bracket assembly can be easily and rapidly adjusted so the ladder can be positioned at any desired elevation; even extended above the scaffold planking if desired. The mounting bracket assemblies can be easily removed from the ladder to facilitate transportation and storage of the ladder sections.
As will readily be apparent to those skilled in the art, various modifications and alterations can be made to the preferred embodiment described above without departing from the spirit and scope of the invention.