Claims:
What I claim as new and desire to be secured by Letters Patent of the United States is
1. A ladder comprising:
2. The invention of claim 1 further comprising at least one rung, said rung being secured to said web whereby said bracket serves as the means to connect said rung to said side rail.
3. The invention of claim 2 wherein said bracket is formed from an aluminum extrusion.
4. The invention of claim 1 wherein each of said legs has an opening therethrough, said openings being aligned with each other, said hook having a portion extending through both of said openings, and said openings being slightly larger in diameter than said portion whereby said hooks can move relative to said bracket both linearly and pivotally.
5. The invention of claim 4 further comprising at least one rung, said rung being secured to said web whereby said bracket serves as the means to connect said rung to said side rail.
6. A ladder comprising:
7. The invention of claim 6 wherein said locking means comprises an annular member encircling said portion and disposed between said legs.
8. The invention of claim 7 wherein said biasing means comprises a coil spring encircling said portion and having one end bearing against said locking means and the other end bearing against one of said legs.
9. The invention of claim 7 wherein said first and second surfaces are disposed at substantially a right angle to each other with the edge therebetween beveled to provide clearance for said annular member as it is rotated relative to said bracket.
10. A ladder comprising:
11. The invention of claim 10 further comprising a locking surface on each of said brackets, locking means on said hook operable to engage and lock against said locking surface when said hook is in said retracted position.
12. The invention of claim 10 further comprising a locking surface on each of said brackets, locking means on said hook operable to engage said locking surface on one of said brackets whereby, when said hook is in said operative position, it is locked in engagement against said locking surface on one of the brackets.
Description:
BACKGROUND OF THE INVENTION
This invention relates generally to ladders and, more specifically, to an improved retractable hook assembly for a ladder. The term "ladder" as used herein includes scaffold frames, and other devices, wherein a retractable hook assembly of the character described may be employed.
It is desirable for some jobs to have a ladder with one or more hooks at its upper end which can be hooked over a cable or other device to maintain the ladder in its erected position. This could be achieved, of course, by providing rigid hooks permanently projecting from the ladder but such hooks interfere with convenient storage of the ladder when it is not in use. Thus, it would be desirable to provide a ladder with hooks which can be easily and conveniently retracted to facilitate storage of the ladder. Ideally, the hook can be moved to and from its retracted position with one hand so that the other hand is free to steady or hold the ladder. Moreover, the connection of the hook to the ladder must be secure and the hook must be positively retained in both its retracted and operative positions.
Accordingly, it is an object of this invention to provide an improved retractable hook assembly for a ladder.
SUMMARY OF THE INVENTION
Briefly stated, in accordance with one aspect of the present invention, there is provided a ladder having at least one side rail. A bracket is secured to the side rail and has a locking surface. A recess is provided adjacent the locking surface and a hook extends through the bracket and has a retracted or stored position and an operative position. Locking means are secured to the hook and have first and second surfaces. The hook and locking means have a first position wherein one of the first and second surfaces is in locking engagement with the locking surface and a second position wherein the first and second surfaces are in alignment with the recess. Biasing means are provided to urge the locking means toward its first position. The hook and locking means are movable relative to the bracket whereby the hook and locking means can be manually moved to their second position and rotated relative to the bracket to selectively bring either of the first and second surfaces into locking engagement with the locking surface. The hook is in its stored position when the first surface is in locking engagement with the locking surface and in its operative position when its second surface is in locking engagement with the locking surface.
BRIEF DESCRIPTION OF THE DRAWING
While the specification concludes with claims particularly pointing out and distinctly claiming the subject matter which is regarded as the invention, it is believed the invention will be better understood from the following description of the preferred embodiments taken in connection with the accompanying drawing, in which:
FIG. 1 is a perspective view of a ladder employing the improved hook assembly of the present invention;
FIG. 2 is a fragmentary detailed view of one of the hook assemblies of the ladder of FIG. 1;
FIG. 3 is a sectional view taken along line 3-3 of FIG. 2;
FIG. 4 is a view similar to that of FIG. 2 but showing the assembly in a position intermediate the retracted position and the operative position;
FIG. 5 is a sectional view taken along line 5-5 of FIG. 4; and,
FIG. 6 is a view similar to that of FIG. 2 but illustrating a second embodiment of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the drawings, there is illustrated a ladder 10 having side rails 11 and 12 with rungs 13 extending therebetween. At the upper end of ladder 10 a pair of hook assemblies 14 are provided for the purposes discussed above. As illustrated, ladder 10 may take the form of an extension ladder having upper and lower portions with the upper portion maintained in an erected relationship with respect to the lower portion by means of a rung lock 15. It is to be understood, however, that the hook assembly of the present invention could be utilized with any type of ladder having side rails whether of unitary design or of an extension design.
Referring now to FIGS. 2, 3, 4 and 5, the hook assembly 14 is illustrated in detail. Side rail 12 includes a central web 16 to which a bracket 17 is secured by means of screws or bolts 18. Bracket 17 is generally C-shaped and includes two spaced legs 19 and 20 interconnected by a web 21. The distal, or free, end of legs 19 and 20 are provided with openings through which screws 18 extend to secure bracket 17 to web 16. In the preferred form of the present invention, bracket 17 is formed from aluminum by an extrusion process and later cut into the appropriate width.
Leg 19 is provided with an opening 22 and leg 20 is provided with a similar opening 23. Openings 22 and 23 are aligned with each other and receive a portion 24 of hook 25. Portion 24 is substantially linear in configuration and circular in cross section. At the upper termination of portion 24, hook 25 is flattened and given an arcuate configuration to form a hook portion.
A locking means or locator 26 is secured to portion 24 by means of a rivet 27, or other suitable securing means, so as to be positioned between legs 19 and 20. Locator 26 is of generally square cross section which provides at least two locator, or locking, surfaces 28 and 29. The sharp edge which would normally be defined by the intersection surfaces 28 and 29 is rounded off to provide a bevel 30. As will become evident as this description proceeds, bevel 30 is provided to give clearance as hook 25 is pivoted between its operative and retracted positions.
A biasing means or coil spring 31 is positioned to encircle portion 24 and bear against leg 20 at one end and against locator 26 at its other end. Spring 31 thus urges locator 26 upwardly to the position illustrated in FIG. 2. When locator 26 is in the position illustrated in FIG. 2, surface 29 is in locking or locating engagement with a locking surface 32 on web 21. In this position, hook 25 is in its operative position.
A recess 33 is positioned adjacent surface 32 so that, as hook 25 is moved linearly with respect to bracket 17, locator 26 moves into alignment with recess 33. When locator 26 is in alignment with recess 33, hook 25 and locator 26 may be rotated or pivoted relative to bracket 17 so as to bring surface 28 into locking engagement with surface 32 as hook 25 and locator 26 are linearly returned to the position wherein locator 26 engages leg 19. FIGS. 4 and 5 illustrate hook 25 and locator 26 in the position wherein locator 26 is aligned with recess 33 and has been partially pivoted with relationship to bracket 17. In FIG. 5, it can be seen how bevel 30 provides clearance for locator 26 to rotate within recess 33.
Spring 31, of course, retains either of surfaces 28 and 29 in locking engagement with surface 32 at all times other than when the user of the ladder manually overcomes the biasing force of spring 31 to move locator 26 into alignment with recess 33. The mechanical locking engagement between either of surfaces 28 or 29 and surface 32 provides a rigid and positive locating or locking of hook 25 relative to side rail 12.
The uppermost of rungs 13 may be secured between the two hook assemblies 14 to provide an even more secure assemblage. To achieve this, rung 13, which in the preferred form of the present invention is a hollow extruded aluminum rung, fits over a boss 34. Boss 34 is also of tubular construction and slips over an element 35 which extends through an opening in web 21. Element 35 is secured to web 21 by means of a rivet 36, or other suitable securing means. Rung 13 is secured to boss 34 by a rivet 37 or other suitable securing means.
Referring now to FIG. 6, a slightly modified embodiment of the present invention is illustrated. In order to simplify the explanation, those elements which are common to both the embodiment of FIG. 6 and the embodiment described above, have been given identical reference numerals. The primary distinction between the embodiment of FIG. 6 and that described above is that bracket 38 is slightly modified from bracket 17. Bracket 38 has a locking surface 39 located adjacent the distal end of one of its legs 40. A recess 41 is defined adjacent surface 39 by the distal ends of legs 40. The operation of the embodiment of FIG. 6 is identical to that of the embodiment described above. Hook 25 is manually linearly moved relative to bracket 38 to compress spring 31. This movement brings locator 26 into alignment with recess 41 whereupon hook 25 and locator 26 may be pivoted relative to bracket 38. Hook 25 and locator 26 are then allowed to move linearly under the force of spring 31 to bring a surface on locator 26 into locking engagement with surface 29.
As mentioned above, in the preferred form of the present invention bracket 17 is formed from an aluminum extrusion and later cut too the appropriate width. By forming bracket 17 in this manner, a very rigid element is provided and the locking surfaces 32 or 39 can be properly formed at the time the extrusion is made. Because the aluminum extrusion provides a rigid structure, the bracket can be used to support the rung as shown in the drawing. This allows proper spacing between the top rung of the ladder and the adjacent rung. If a bracket less rigid than the extruded one were employed, the top rung would have to be positioned closer to or farther from the adjacent rung to allow proper positioning of the bracket. Thus, an extruded aluminum bracket is employed in the preferred form of the present invention.
It should now be apparent that the present invention provides an improved retractable hook assembly for a ladder wherein the hook is positively retained in both its retracted and operative positions and the hook can be moved to and from its retracted position with one hand by the user of the ladder.
As will be evident from the foregoing description, certain aspects of the invention are not limited to the particular details of construction of the examples illustrated, and it is contemplated that various other modifications or applications will occur to those skilled in the art. It is, therefore, intended that the appended claims shall cover such modifications and applications as do not depart from the true spirit and scope of the invention.