Title:
Anti-slip attachment for ladders
Kind Code:
A1


Abstract:
An anti-slip attachment for a ladder that forms a frictional engagement between the ladder and a metal gutter, so as to prevent the ladder from slipping laterally thereon. A layer of resiliently compressible material having a high surface coefficient of friction against smooth metal is mounted to the ladder so that it will bear against and be compressed by an edge of the gutter. The layer of resiliently compressible material may be at least one strip of resiliently compressible foam tape. The resiliently compressible material may be adhered directly to the side rails of the ladder so as to bear against the edge of a gutter when the ladder is rested thereon, or the layer or layers of resiliently compressible material may be mounted to a separate frame or bracket that is in turn mounted to the ladder itself. The anti-slip attachment helps to reduce the likelihood of fall injuries due to the ladder slipping sideways along a metal gutter during use.



Inventors:
Corston, Charles (Bellingham, WA, US)
Application Number:
10/994785
Publication Date:
06/02/2005
Filing Date:
11/22/2004
Assignee:
CORSTON CHARLES
Primary Class:
International Classes:
E06C7/00; E06C7/06; E06C7/46; E06C7/48; (IPC1-7): E04G5/02
View Patent Images:
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Primary Examiner:
CHIN-SHUE, ALVIN CONSTANTINE
Attorney, Agent or Firm:
TODD N. HATHAWAY (BELLINGHAM, WA, US)
Claims:
1. An anti-slip attachment for a ladder that forms a frictional engagement between said ladder and a metal gutter, said anti-slip attachment comprising: a layer of resiliently compressible material having a high surface coefficient of friction against smooth metal; and means for mounting said layer of resiliently compressible material to a ladder so that said layer will bear against and be compressed by an edge of a metal gutter when said ladder is rested thereon; whereby said layer of resiliently compressible material establishes a frictional engagement that prevents said ladder from slipping laterally along said edge of said gutter.

2. The anti-slip attachment of claim 1, wherein said layer of resiliently compressible material comprises: at least one elongate strip of said resiliently compressible material.

3. The anti-slip attachment of claim 2, wherein said means for mounting said layer of resiliently compressible material to a ladder comprises: a layer of adhesive on said strip of resiliently compressible material for adhering said strip to a face of at least one elongate side rail of a ladder.

4. The anti-slip attachment of claim 3, wherein said strip of resiliently compressible material comprises: a roll of resiliently compressible tape having said layer adhesive formed thereon.

5. The anti-slip attachment of claim 1, wherein said means for mounting said layer of resiliently compressible material to a ladder comprises: a frame having said layer of resiliently compressible material mounted to a face thereof; and means for mounting said frame to a ladder so that said face of said frame bears against a gutter when said ladder is rested thereon.

6. The anti-slip attachment of claim 5, wherein said frame comprises: first and second clip members that are attachable to first and second side rails of a ladder so that said layers of resiliently compressible material are positioned between said side rails and a gutter when said ladder is rested thereon.

7. The anti-slip attachment of claim 5, wherein said frame comprises: first and second bracket members for fitting over first and second side rails of a ladder so that said layers of resiliently compressible material are positioned between said side rails and a gutter when said ladder is rested thereon; and a tie rod for passing through a stave of said ladder so as to join said brackets and secure said bracket members on said side rails of said ladder.

8. The anti-slip attachment of claim 1, wherein said layer of resiliently compressible material comprises: a layer of resiliently compressible foam material.

9. The anti-slip attachment of claim 8, wherein said resiliently compressible foam material comprises: resiliently compressible PVC foam material.

10. The anti-slip attachment of claim 1, wherein said layer of resiliently compressible material comprises: a layer of resiliently compressible material having a durometer selected so that said layer will be only partially compressed when pressed against an edge of a gutter by a ladder at a predetermined angle and maximum load, so that said layer will retain a reserve range of compression when said ladder is fully loaded.

11. The anti-slip attachment of claim 10, wherein said durometer is selected so that said layer will be compressed only about 50 percent when pressed against an edge of a gutter by a ladder at said predetermined angle and maximum load, so that said layer will retain a reserve range of compression of about 50 percent when said ladder is fully loaded.

12. An anti-slip ladder assembly that forms a frictional engagement with a metal gutter, said ladder assembly comprising: a ladder; and a layer of resiliently compressible material having a high surface coefficient of friction against smooth metal, said layer of compressible material being mounted to said ladder so that said layer will bear against and be compressed by an edge of a metal gutter when said ladder is rested thereon; whereby said layer of resiliently compressible material establishes a frictional engagement that prevents said ladder from slipping laterally along said edge of said gutter.

13. The anti-slip ladder assembly of claim 12, wherein said layer of resiliently compressible material comprises: an elongate strip of resiliently compressible material that is mounted to a face of at least one elongate side rail of said ladder.

14. The anti-slip ladder assembly of claim 12, wherein said layer of resiliently compressible material comprises: first and second elongate strips of resiliently compressible material adhered to faces of first and second side rails of said ladder.

15. The anti-slip ladder assembly of claim 12, wherein said assembly further comprises: a frame having said layer of resiliently compressible material mounted to a face thereof; and means for mounting said frame to a said ladder so that a said face of said frame bears against a gutter when said ladder is rested thereon.

16. The anti-slip ladder assembly of claim 15, wherein said frame comprises: first and second clip members that are attachable to first and second side rails of a ladder so that said layers of resiliently compressible material are positioned between said side rails and a gutter when said ladder is rested thereon.

17. The anti-slip ladder assembly of claim 15, wherein said frame comprises: first and second bracket members for fitting over first and second side rails of a ladder so that said layers of resiliently compressible material are positioned between said side rails and a gutter when said ladder is rested thereon; and a tie rod for passing through a hollow stave of said ladder so as to join said brackets and secure said bracket members on said side rails of said ladder.

18. The anti-slip ladder assembly of claim 12, wherein said layer of resiliently compressible material comprises: a layer of resiliently compressible foam material.

19. The anti-slip ladder assembly of claim 18, wherein said resiliently compressible foam material comprises: resiliently compressible PVC foam material.

20. The anti-slip ladder assembly of claim 12, wherein said layer of resiliently compressible material comprises: a layer of resiliently compressible material having a durometer selected so that said layer will be only partially compressed when pressed against an edge of a gutter by a ladder at a predetermined angle and maximum load, so that said layer will retain a reserve range of compression when said ladder is fully loaded.

21. The anti-slip ladder assembly of claim 20, wherein said durometer is selected so that said layer will be compressed only about 50 percent when pressed against an edge of a gutter by a ladder at said predetermined angle and maximum load, so that said layer will retain a reserve range of compression of about 50 percent when said ladder is fully loaded.

22. A method for forming a frictional engagement between a ladder and a metal gutter, said method comprising the steps of: mounting to a ladder a layer of resiliently compressible material having a high surface coefficient of friction against smooth metal; and resting said ladder against a metal gutter so that said layer of resiliently compressible material bears against and is compressed by an edge of said metal gutter; whereby said layer of resiliently compressible material establishes a frictional engagement that prevents said ladder from slipping laterally along said edge of said gutter.

23. The method of claim 22, wherein the step of mounting said layer of resiliently compressible material to a ladder comprises: mounting an elongate strip of said resiliently compressible material to a face of at least one elongate side rail of said ladder.

24. The method of claim 23, wherein the step of mounting an elongate strip of said resiliently compressible material to at least one side rail of said ladder comprises adhering first and second strips of said resiliently compressible material to first and second side rails of said ladder.

25. The method of claim 22, wherein the step of mounting said layer of resiliently compressible material to a ladder comprises: mounting said layer of resiliently compressible material to a face of a frame; and mounting said frame to said ladder so that said face of said frame bears against a gutter when said ladder is rested thereon.

26. The method of claim 22, wherein the step of mounting a layer of resiliently compressible material to a ladder comprises: mounting to said ladder a layer of resiliently compressible foam material.

27. The method of claim 26, wherein said resiliently compressible foam material is a PVC foam material.

28. The method of claim 22, further comprising the step of: selecting said layer of resiliently compressible material to have a durometer such that said layer will be only partially compressed when pressed against an edge of a gutter by said ladder at a predetermined angle and maximum load, so that said layer will retain a reserve range of compression when said ladder is fully loaded.

Description:

RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Patent Application No. 60/524,134 filed on Nov. 20, 2003.

BACKGROUND

a. Field of the Invention

The present invention relates generally to safety devices for ladders, and, more particularly, to an attachment for preventing ladder from slipping laterally against a gutter during use.

b. Background

Ladders in general, and extension ladders in particular, present significant safety concerns. It is well documented that falls from ladders result in numerous injuries and deaths on an annual basis.

One particular hazard is the tendency of ladders to slip sideways when resting against gutters. As can been seen in FIG. 1, a person 10 when cleaning or repairing a gutter 12 tends to reach out to one side or the other when working, due to the inconvenience involving in descending and moving the ladder 14 to another location, with the result that this unbalances the ladder and tends to cause it to slide laterally on the gutter and possibly topple over. Even more dangerous is the tendency of the ladder to slip when attempting to step onto it from the roof in order to descend, when the user is facing backwards and feeling for a rung with his foot.

The frequency of this hazard is increasing due to the increasing use of aluminum (and other metal and slippery-surfaced materials) in the construction of both gutters and ladders. For example, when an aluminum extension ladder is placed against an aluminum gutter there is almost no frictional resistance to the ladder sliding laterally.

As a partial solution, some ladders have been fitted with various forms of stabilizing struts and braces which rest against the ground. These are at best only a partial solution, and become less effective as the ladder is extended to increased heights. Moreover, the struts and braces are cumbersome and make the ladder to difficult to store or transport, and also add significant cost.

Accordingly, there exists a need for an attachment for effectively preventing a ladder from slipping laterally when placed against a gutter or similar structure or surface. Furthermore, there exists a need for such an attachment that is effective regardless of the height to which the ladder is extended. Still further, there exists a need for such an attachment that does not encumber the transportation or storage of the ladder, or otherwise compromise its use. Still further, there exists a need for such an attachment that can be used with a wide variety of conventional ladders, both new and those already in use, without requiring significant modification thereof. Still further, there exists a need for such an attachment that is inexpensive and yet durable and long lasting in use.

SUMMARY OF THE INVENTION

The present invention has solved the problems cited above, and is an anti-slip attachment for a ladder that forms a frictional engagement between the ladder and the metal gutter or similar structure when the ladder is placed thereon.

Broadly, the invention comprises (a) a layer of resiliently compressible material having a comparatively high surface coefficiency of friction against smooth metal, and (b) means for mounting the layer of resiliently compressible material to a ladder so that the layer will bear against and be partially compressed by the edge of the gutter when the ladder is rested thereon.

The layer of resiliently compressible material may comprise a strip of the resiliently compressible material, and the means for mounting the material to the ladder may comprise an adhesive for being adhered to the forward faces of the side rails of the ladder. The strip may comprise a roll of the resiliently compressible material having an adhesive backing.

Alternatively, the means for mounting the layer of resiliently compressible material to the ladder may comprise a frame having the resiliently compressible material mounted to a face thereof, and means for mounting the frame to the ladder. The frame may comprise first and second clips that are mountable to the side rails of the ladder so that the faces having the layer of resiliently compressible material are directed towards the gutter when the ladder is placed thereon.

The resiliently compressible material may comprise a resiliently compressible foam material. The resiliently compressible foam material may be a PVC foam material.

The layer of resiliently compressible material may be configured so that the material will be only partially compressed when forced against the gutter under a predetermined maximum operating load of the ladder, so that the layer of resiliently compressible material will retain a reserve range of compression when the ladder is fully loaded. The reserve range of compression may be about 50% of the total range of compression of the layer of material.

The present invention also provides an anti-slip ladder assembly, comprising (a) a ladder, and (b) a layer of resiliently compressible material having a comparatively high surface coefficient of friction that is mounted to the ladder so as to bear against and engage an edge of a gutter when the ladder is placed thereon. The layer of resiliently compressible material may comprise first and second strips of resiliently compressible material that are adhered to the faces of first and second side rails of the ladder. The resiliently compressible material may comprise strips of resiliently compressible foam material having an adhesive backing. The resiliently compressible material may comprise resiliently compressible PVC foam material. The layer of resiliently compressible material may be configured so that the material will be only partially compressed when forced against the gutter under a predetermined maximum operating load of the ladder, so that the layer of resiliently compressible material will retain a reserve range of compression when the ladder is fully loaded. The reserve range of compression may be about 50% of the total range of compression of the layer of material.

The invention further provides a method for forming a frictional engagement between a ladder and a metal gutter, comprising the steps of mounting to a ladder a layer of resiliently compressible material having a high surface coefficient of friction against smooth metal, and resting the ladder against a metal gutter so that the layer of resiliently compressible material establishes a frictional engagement that prevents the ladder from slipping laterally along the edge of the gutter.

These and other features and advantages of the present invention will be apparent from a reading of the following detailed description with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an elevational, environmental view of a ladder in accordance with the prior art, showing the manner in which this tends to slip along the gutter as the operator reaches to one side;

FIG. 2 is an elevational view of a ladder having an anti-slip attachment in accordance with the present invention adhered thereto, showing the manner in which the attachment engages the metal gutter of a house when placed thereon;

FIG. 3 is an enlarged, cross-sectional view of the area of contact between the ladder of FIG. 2 and the gutter against which it is placed, showing the manner in which the compressible layer of the anti-slip attachment yields resiliently to conform to and engage the surface of the gutter;

FIG. 4 is an elevational, partial view of a ladder having a strip of compressible material being applied thereto from a roll of the material, so as to form the anti-slip attachment of FIGS. 2-3;

FIG. 5 is an elevational view, similar to FIG. 2, showing an anti-slip attachment in accordance with a second embodiment of the present invention, in which the yieldingly compressible material is mounted to a pair of clips that are fitted over the side rails of the ladder, the ladder being shown in a cross-section taken along line 5-5 in FIG. 6;

FIG. 6 is an elevational view of the ladder and anti-slip attachments of FIG. 5, showing the position of the clips on the side rails of the ladder; and

FIG. 7 is a cross-sectional view of the ladder and anti-slip attachments of FIGS. 5-6, taken along line 7-7 in FIG. 6, showing the manner in which the clips fit over and engage the side rails of the ladder;

FIG. 8 is an elevational view, similar to FIG. 5, showing an anti-slip attachment in accordance with a third embodiment of the present invention, in which the yieldingly compressible material is mounted to a pair of channel-shaped frames that are slipped over the side rails of the ladder;

FIG. 9 is a perspective view of one of the slip-on, channel-shaped frames of FIG. 8, showing the configuration of the frame and the strip of resiliently compressible material thereon in greater detail;

FIG. 10 is a first partial, elevational view of the ladder and one of the slip-on frames of FIGS. 8-9, showing the manner in which the upper end of a side rail enters and is received in the channel-shaped frame as the latter is slid onto the rail;

FIG. 11 is a second partial, elevational view of the side rail and slip-on frame of FIG. 10, showing the manner in which the side rail fits within and is engaged by the channel-shaped frame as the frame is slid onto the rail and into the desired position;

FIG. 12 is a cross-sectional view, taken along line 12-12 in FIG. 11, showing the relationship of the channel-shaped frame and strip of resiliently compressible material to the side rail of the ladder in greater detail; and

FIG. 13 is a cross-sectional view of an anti-slip attachment assembly in accordance with a fourth embodiment of the present invention, showing the manner in which the brackets thereof are mounted by a threaded rod which passes through one of the staves of the ladder.

DETAILED DESCRIPTION

The present invention is an anti-slip attachment for a ladder which frictionally engages the surface of a metal gutter or similar surface structure so as to prevent the ladder from sliding thereon. FIGS. 2-7 illustrate two embodiments of the invention.

In the first preferred embodiment that is illustrated in FIG. 2, the attachment is formed of a strip of resiliently compressible material 20 that is adhered to the forward face 22 of each rail 24 of the ladder 26. The surface of the resiliently compressible layer 20 will consequently bear against the lip 28 of the gutter 30 when the ladder is placed thereon, as shown in FIG. 2.

The pressure of the ladder against the gutter causes the lip 28 of the gutter to press into the resilient material of the anti-slip attachment, as shown in FIG. 3. This causes the resiliently compressible material to deform so that its surface follows the contour of the gutter lip, forming a contact patch 32 having an increased surface area. The compressible material is selected to have surface qualities similar to that of soft rubber, i.e., it has a high degree of “tackiness” and resistance to slipping when pressed against a smooth metal surface. The material thus has a high surface coefficient of friction, e.g., a static coefficient of friction (μs) well above 0.5 and preferably above about 0.9.

The large contact patches 32 consequently establish a firm frictional engagement with the lip of the gutter that prevents the ladder from sliding laterally thereon. Moreover, any tipping movement will cause the rail of the ladder on the side towards the direction of tipping to slide downwardly (as well as laterally) against the gutter (see FIG. 1); as this happens, the material of the compressible strip in the area 34 just above the contact patch (see FIG. 3) will tend to build or “mound” up so as to abut the upper surface 36 of the gutter lip, further acting to arrest the movement of the ladder.

In combination, these actions of the resiliently compressible strips (i.e., the frictional engagement of the contact patch in combination with the abutment of the material against the upper surface of the gutter lip) are extremely effective in preventing the ladder from developing any tipping or sliding motion during use; in prototype testing, using anti-slip strips in accordance with the preferred embodiment of the present invention, it has been found essentially impossible for a person to cause the ladder to slide laterally against an aluminum gutter, even when pulling forcefully in a sideways direction on the gutter itself.

Another particular advantage of the elongate configuration of the strips of resiliently compressible material is that this makes it very easy for the operator to position the anti-slip material against the edge of the gutter, regardless of differences in the height of the gutter above the ground. As is well know, the height of most extension ladders is adjustable only in increments (typically, by the distance between the individual staves of the ladder); the vertical length of the elongate strips avoids the problem of the anti-slip areas being positioned above or below the gutter when the ladder is adjusted to the nearest incremental height. The elongate dimension of the strips also prevents them from moving off of and losing contact with the edge of the gutter in the event that some movement occurs that changes the angle of the ladder relative to the gutter. For most conventional extension ladders, it is preferred that the length of the strips be at least as great as the spacing between the staves/rungs (e.g., about 10-16 inches), although much longer strips (e.g., 3-5 feet or more) may be advantageous from the standpoint of convenience. Moreover, it will be understood that in some embodiments the resiliently compressible, anti-slip material may be provided in other shapes besides elongate, rectangular strips, for example, in an oval or rounded configuration.

In order for the anti-slip strips to provide the above advantages, it is important that the resiliently compressible material be selected to have a durometer, or indentation hardness, in combination with its thickness such that it will significantly compress but will not “bottom out” against the ladder rails 22 under normal loads. In other words, the material is preferably selected so that, when the ladder with which it is used is at its maximum normally acceptable inclination and working load, with the rails of the ladder pressing against the edge of the gutter, the material will not be completely collapsed and will retain a degree of compressible travel. Thus, as is shown in FIG. 3, even when the ladder is bearing the full load of a user and associated tools, etc., the material of the strips 20 has not bottomed out, and an area 38 of reserve compression remains available between the gutter lip and the forward faces 22 of the ladder rails. The amount of reserve compression may vary depending on design factors, however, it is generally suitable that the material be selected to yield by about 50% of its total available compression when subjected to a maximum operating load of the ladder within a specified range of lean angles.

As can be seen with further reference to FIG. 3, each of the strips 20 of the anti-slip attachment of the preferred embodiment is formed by a layer of resiliently compressible foam material 40 backed by a layer of adhesive 42 that affixes the compressible material to the face 22 of the rail. FIG. 4, in turn, illustrates a method in which the anti-slip material is conveniently supplied in the form of a roll 34 of adhesive cushioning tape. This can be packaged and supplied to the purchaser, separately from or together with the ladder as desired, and is easily applied to the faces of the rails 24 by simply unrolling the tape in a conventional fashion and pressing it against the surface 22 so that the material adheres firmly thereto. It will be understood, however, that other forms of application may be employed, for example, the resiliently compressible material may be extruded or molded directly on the faces of the ladder rails in an OEM operation, or may be formed as an integral part of the faces of the rails themselves.

Suitable adhesive foam tape material is available from Saint-Gobain Performance Plastics, Granville, N.Y., with equivalent products being available from other manufacturers. Cellular PVC (polyvinyl chloride) foam material is generally preferred due to its comparatively high surface coefficient of friction and its ability to establish firm frictional engagement under both wet and dry conditions, plus its overall durability and resistance to abrasion; it will be understood, however, that other resilient materials may be used, such as urethane, polyurethane, silicone or rubber foams or various non-cellular rubber-like materials, for example. Using firm PVC foam material in readily available durometers, suitable dimensions for the adhesive tape are 1⅛ inches wide by ⅜ inch thick, which again may vary depending on design factors.

One example of an eminently suitable high-density, closed-cell PVC foam material, available from Saint-Gobain Performance Plastics, has the properties set forth in the following Table A:

TABLE A
PropertiesTest MethodValue
Thickness, inches (mm).375 (8.5)
HardnessShore OO52
Density lbs./ft3 (kg/m3)ASTM D1667  15 (240)
Compression Force Deflection psiASTM D1667  9 (64)
(kPa) @ 30%
Force to Compress, psi (kPA) @ASTM D1667  14 (94)
30%

In the second embodiment, which is illustrated in FIGS. 5-7, there are first and second clips, 50a, 50b that attach to the two rails 52a, 52b of the ladder and which engage the lip 28 of the gutter 30 in substantially the same manner as described above. The clips consequently provide separate frames on which the tape is mounted, which are in turn mountable to the ladder.

As can be seen in FIG. 7, each of the clips is formed in the shape of semi-enclosed channel. In the illustrated embodiment the channel is constructed of steel-sheet metal, however, it will be understood that plastic or other suitable materials may be used. The channel includes a comparatively wide web 54 having a flange 56 along its forward edge, the strip of foam material 58 being adhered to the outer surface thereof. A second flange 58 along the opposite edge of the web 54 is bent back parallel to the web so as to form a return 60 that defines semi enclosed U-shaped channel area 26. The inside angle between the web and the forward flange 56 is somewhat less than 90°, e.g., 80-85°.

To install one of the clips on a rail of the ladder, the U-shaped channel area 60 is first slipped over the rearward flange 64 of the ladder rail and the clip is then pulled/pushed forwardly. When the rearward flange of the ladder is fully seated against the rearward flange 58 of the clip, as is shown in FIG. 7, the forward flange 56 is bent forwardly to widen the spacing between the forward and rearward flanges of the clip sufficiently that the former can be slipped over the forward flange 66 of the ladder rail. When the clip has been pressed home, so that its web lies generally parallel to the web 68 of the ladder rail, the forward flange 56 snaps resiliently back to its initial orientation to lock the clip in place. The strip of resiliently compressible anti-slip material is thus positioned so that it will be compressed between the gutter and the rail of the ladder during use.

In a third embodiment, which is illustrated in FIGS. 8-12, there are two channel-shaped frames 70a, 70b (only 70a being visible in FIG. 8), that have a channel-shaped configuration and that slip over the two side rails 72a, 72b of the ladder rather than clipping onto them in the manner shown in FIGS. 5-7.

As can be seen in FIG. 9, each of the slip-on frames has a generally channel-shaped configuration, with a side web 74 and forward and rearward flanges 76, 78 with returns 80, 82, that in combination define a semi-enclosed, U-shaped channel area 84; the generally U-shaped configuration facilitates manufacture of the frames from stamped/bent sheet metal, however, it will be understood that in some embodiments that the channel areas may be fully enclosed. A strip 86 of the resiliently compressible material is mounted to the forwardly-directed face of each forward flange 76, in a manner similar to the embodiment described with regard to FIGS. 5-7. However, at the upper and lower ends of the rearward flange 78 a pair of ramp-shaped biasing members 88a, 88b protrude inwardly towards the channel area 84. In the embodiment that is illustrated, the biasing members are formed of separate pieces of resiliently flexible material (e.g., metal or plastic), each having a mounting portion 90 that is spot welded, bonded or otherwise mounted to the inside surface 92 of the rearward flange 78 (see FIG. 10), with a leaf portion 94 that bends forwardly from the mounting portion so as to extend into the channel area. This provides the advantage of being able to form the biasing members of a material having superior resiliency and wear characteristics as compared with the material of the frame; however, it will be understood that in some embodiments the biasing members may be formed integrally (e.g., stamped or molded) with and of the same material as the frame itself.

As can be seen in FIG. 10, the side web 74 and therefore the channel area 84 is sized somewhat wider than the side rail of the ladder. The leaf portions 94 of the biasing members 88a, 88b include main ramp portions 96 that extend into the channel area to define a width that in turn is less than that of the side rails; distal ramp portions 98 at the ends of the main ramp portions are angled back outwardly towards the rearward side of the frame.

Accordingly, as can be seen in FIG. 10, the frame members 70a, 70b can be slid onto the upper ends of the side rails 72a, 72b, in the direction indicated by arrow 100. As this is done, the distal ramp portion 98 contacts and rides over the upper, rearward corner of the side rail (which is typically radiussed as shown), so that the leaf portion of the biasing member is forced outwardly in the direction indicated by arrow 104. As a result, the leaf portion develops an inward bias against the rearward surface 106 of the rail as the frame is slid thereover.

As a result, the upper and lower biasing members 88a, 88b maintain a constant inward pressure towards rails, as indicated by arrow 110 in FIG. 11. This generates a sliding but comparatively high-friction engagement at the contact areas between the rearward surfaces 106 of the rails and the junctures/apexes 108 of the ramp portions of the biasing members. The frictional engagement is sufficiently high to hold the frames in place, but low enough to be overcome by simply grasping the frames and pushing them in one direction or the other. Consequently, the operator is able to conveniently slide the frames to the desired location along the rails, at which the strips of resiliently compressible material will contact the gutter, after which the frictional engagement will maintain the frames in position and prevent them from sliding until the operator next desires to adjust their positions. Furthermore, as can be seen in FIG. 12, the forward pressure exerted by the biasing members holds the forward flange of the frame firmly in place against the front surface 112 of the rail, so as to form a stable interfit in which the anti-slip strips 86 are properly positioned at the front edges of the ladder.

FIG. 13 shows a fourth embodiment of the invention, in which the frames 120a, 120b have a somewhat simplified configuration, with the forward and rearward flanges 122, 124 extending at right angles to the webs 126. As with the embodiments described above, the strips of resiliently compressible cushioning material 128 are adhered to the outer surfaces of the forward flanges 122. In this embodiment, however, mounting is accomplished by means of a threaded rod 130 that passes through a hollow interior of one of the staves 132 of the ladder; conventionally, the staves of aluminum ladders are hollow and open at each end so that the rod can be readily passed therethrough. First and second wing nuts 134 are mounted on the ends of the rod 130 and secure the clips to the rails of the ladder when tightened; suitably, the rod is a 20-inch length of ¼-inch ready rod, with ¼-inch wing nuts on each end. However, it will be understood that in some embodiments a nut may be used on only one end of the rod, with the other end being a bolt head or fixed to the opposite clip; moreover, other attachment and tightening means may be used in other embodiments.

The embodiments which are shown in FIGS. 5-13 illustrate just a few of many different structures that may be used to provide an anti-slip attachment in which the resiliently compressible material mounts to the ladder via a secondary structure or frame rather than being adhered directly to the ladder rails themselves. As a general rule, those embodiments which employ secondary structures that are faced with the non-slip compressible material may be somewhat more costly than the first embodiment described above (i.e., in which the compressible tape is adhered directly to the faces of the rails), however, they may offer certain advantages in terms of being able to provide contact patches that are wider (and therefore “grippier”) than those which are limited to the width of the individual rails of the ladder. It will be understood, however, that all such embodiments fall within the scope and spirit of the present invention, regardless of the whether the resiliently compressible material is mounted directly on the rails of the ladder or on a secondary frame or structure that in turn mounts to the rails and/or staves of the ladder.

It is to be recognized that various alterations, modifications, and/or additions may be introduced into the constructions and arrangements of parts described above without departing from the spirit or ambit of the present invention.