Safety stilt

Abstract

A safety stilt for users requiring extended access to overhead or elevated surfaces has two slidably mated shells able to be adjusted to a variety of heights. Foot attachment means are attached to a top surface on the upper shell and a base defines a greater surface area than the surface area defined by the top surface.

Description

FIELD OF THE INVENTION

The present invention relates to improved vertically adjustable safety stilts used to increase the height of wearers working in an overhead environment such as drywalling, painting, and electrical work. The stilt has a stable base and a safety release foot attachment mechanism that will release in the event of a fall, greatly improving a user's chance of landing safely.

BACKGROUND

Workers in such occupations as drywall, painting, texturing or electrical work frequently must work in an overhead or ceiling environment that is, for most workers, far above the head and out of arm's reach. Several types of stilts have been previously developed in an effort to assist overhead workers. U.S. Pat. No. 5,645,515 to Armstrong et al. describes a spring loaded parallelogram stilt having foot straps and leg straps attached to a raised leg which attaches below the wearer's knee. A different concept is described by Hale in U.S. Pat. No. 5,593,373 wherein a shoe like device is provided with straps for attaching a human foot as well as a second strap, which extends below a user's foot to attach to an inverted bucket. An adjustable leg for stilts is described in U.S. Pat. No. 4,569,516 to Masterson wherein vertically slidable upper and lower struts are interfitted and provided with foot and leg straps. U.S. Pat. No. 3,595,339 to Ballard et al. describes a pair of spring loaded, adjustable stilt boots. Vertically configured sliding adjustable riser halves having non-breakaway foot straps are described in U.S. Pat. Des. No. 217,371, to Clark. U.S. Pat. No. 2,832,079 to Bailey describes a stilt device which features a foot plate with straps for foot attachment with a pair of tubular risers extending downward to a tread-plate approximately the same size as the foot plate. In all cases, the foot plate is no larger than the portion of the stilt contacting the floor, resulting in a less stable device. Also in all cases, attachment means used to secure the user's foot to the stilt device are firmly attached to the stilt and therefore unable to break away in the event of a fall. Thus, what is clearly needed is an improved safety stilt device which offers improved stability. Such a device combined with a safety release foot attachment that allows the user's foot to release from the stilt device in the event that the user falls during use, allowing a greatly reduced chance of falling safely, would be even more desirable.

SUMMARY

In one aspect the invention comprises a safety stilt having a first shell which defines a vertical axis and a horizontal axis, a top surface and a base. The top surface has a lesser surface area than the area defined by the base. A second shell defines a vertical axis and a horizontal axis, a top surface and a base, with the top surface having a lesser surface area than the area defined by the base. The top surface of the second shell is sized and shaped to be slidably received within the base of the first shell, allowing the second shell to move along the vertical axis of the first shell. Additionally, the safety stilt has height adjustment means allowing the relative position between the first shell and the second shell along the vertical axis to be securely adjusted. Releasable foot attachment means allow a user's foot to be secured to the top surface, which will release from the safety stilt if the user falls.

In another aspect the invention comprises a safety stilt having a first shell which defines a vertical axis and a horizontal axis, a top surface and a base. The top surface has a lesser surface area than the area defined by the base, and a wall extends between and connects the top surface and the base. A second shell defines a vertical axis and a horizontal axis, a top surface and a base, with the top surface having a lesser surface area than the area defined by the base. A wall extends between and connects the top surface and the base. The second shell is sized and shaped to be slidably received within the base of the first shell, which allows the top surface of the second shell to move along the vertical axis of the first shell. A rib is configured into the first shell, defines an outer surface and extends from the wall of the first shell. A rib is similarly configured into the second shell, defines an outer surface, and extends from the wall of the second shell. The rib of the first shell further defines an inner surface corresponding with the outer surface of the rib such that the outer surface of the rib of the second shell slidably mates with the inner surface of the rib of the first shell. Height adjustment means are provided which allow the relative position between the first shell and the second shell along the vertical axes to be securely adjusted. Releasable foot attachment means allowing a user's foot to be secured to the top surface are attached to the first shell, which will release from the safety stilt if the user falls.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the first shell.

FIG. 2 is a first side view of the first shell.

FIG. 2A is a cross section taken through the lines 2A-2A as shown in FIG. 2.

FIG. 2B is a cross section taken through the lines 2B-2B as shown in FIG. 2.

FIG. 3 is a second side view of the first shell.

FIG. 4 is a top view of the first shell.

FIG. 5 is a bottom end view of the first shell.

FIG. 6 is a perspective view of the second shell.

FIG. 7 is a first side view of the second shell.

FIG. 7A is a cross section taken through the lines 7A-7A as shown in FIG. 7.

FIG. 7B is a cross section taken through the lines 7B-7B as shown in FIG. 7.

FIG. 8 is a second side view of the second shell.

FIG. 9 is a bottom end view of the second shell.

FIG. 10 is a top view of the second shell.

FIG. 11 is a perspective view of the first and second shells fitted together and assembled to form the present invention.

FIG. 12 is a side view of the present invention with the first and second shells attached to each other to form a stilt having a relatively tall configuration.

FIG. 13 is a side view of the present invention with the first and second shells attached together to form a stilt having a relatively short configuration.

FIG. 14 is a side view of the first shell.

FIG. 15 is a top view of the top surface.

FIG. 16 is a side view of an embodiment of a release fastener.

DETAILED DESCRIPTION

The particulars shown herein are by way of example and for purposes of illustrative discussion of the invention only and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the invention. In this regard, no attempt is made to show structural details of the invention in more detail than is necessary for the fundamental understanding of the invention, the description taken with the drawings making apparent to those skilled in the art how the several forms of the invention may be embodied in practice.

Nomenclature

• 10 First Shell
• 12 Vertical Axis
• 14 Horizontal Axis
• 16 Top Surface
• 18 Wall
• 20 Base
• 21 Lip
• 22 Rib
• 24 Hollow Space
• 26 Raised Ridge
• 28 Heel End
• 30 Toe End
• 40 Height Adjustment Aperture
• 42 Foot Strap Aperture
• 50 Foot Strap Assembly
• 50a Foot Strap Half (Outside)
• 50b Foot Strap Half (Inside)
• 52 Release Fastener
• 54a Bolt
• 54b Nut
• 70 Second Shell
• 72 Vertical Axis
• 74 Horizontal Axis
• 76 Top Surface
• 78 Wall
• 80 Base
• 81 Lip
• 82 Rib
• 84 Hollow Space
• 86 Raised Ridge
• 88 Heel End
• 90 Toe End
• 100 Safety Stilt

Construction

FIG. 1 shows a perspective view of the first shell 10 of the safety stilt 100 of the present invention. It is seen that the first shell 10 defines a vertical axis 12 and a horizontal axis 14 as well as a top surface 16 for receiving a user's foot and a wall 18 which supports and vertically separates the top surface 16 from the base 20. In one embodiment, the top surface 16 defines a plane that is substantially parallel with a plane defined by the perimeter of the base 20. In other embodiments (not shown) the plane defined by the top surface 16 may be at an angle to the plane defined by the perimeter of the base 20, for reasons of comfort or safety. A raised ridge 26 extends above and at least partially surrounds the perimeter of the top surface 16. As shown in FIG. 1, a heel end 28 is surrounded by the ridge 26 whereas a toe end 30 is not surrounded. The purpose of the ridge 26 is to enhance the security and safety of the safety stilt 100 while in use, by providing a tactile guide to when the proper position of the user's foot on the top surface 16 has been located.

The surface area defined by the base 20 is greater than the surface area defined by the top surface 16, which allows a second shell 70 to be slid into the open base 20 of first shell 10, as explained in more detail below. In one embodiment (not shown), a single rib 22 substantially the length of the vertical axis 12 extends in a substantially tapered manner from the base 20 along the wall 18 to the top surface 16 and runs substantially parallel with the vertical axis 12. In other embodiments, as shown in FIGS. 1-2B, 4-5, and 11-15, a plurality of ribs 22 is provided to enhance the overall strength and assembled rigidity of the safety stilt 100, without substantially increasing the weight of the safety stilt 100. FIGS. 2A-2B are cross sections taken through the lines 2A-2A and 2B-2B of FIG. 2 respectively and show that a hollow space 24 is formed behind and corresponds in position with the rib 22 which extends from and is part of the wall 18. It is also understood and therefore within the scope of the invention, that in one embodiment (not shown) the safety stilt will also work without any ribs configured into the wall 18. FIG. 2 shows a first side view (from the wider side—unnumbered) of the first shell 10. FIG. 3 shows a second side view (from the narrower or end side—unnumbered) of the first shell 10. While no ribs are shown on the end (unnumbered) shown in FIG. 3, it is contemplated by and therefore within the scope of the invention to have a rib 22 or ribs 22 on this end also.

In one embodiment, as shown in FIGS. 1-2 and 5, the base 20 is provided with a widened lip 21 surrounding its perimeter which strengthens the base 20 extending its useful life. FIG. 4 shows a top view of the first shell 10 including the top surface 16 to which a human foot can be attached prior to using the safety stilts 100. As best shown in FIG. 15, the top surface 16 may be optionally configured to have a textured surface (unnumbered) which enhances safety by improving the grip between the top surface 16 and a user's foot. FIG. 5 shows a bottom view of the first shell 10 including the perimeter of the base 20, which also shows that the base 20 is open and contains no restrictions to entry. As seen in FIGS. 11-13, at least one foot strap assembly 50, which includes an outside foot strap half 50a and inside foot strap half 50b, is attached proximate the top surface 16 to attach a user's foot to the first shell 10. In one embodiment, the foot strap assembly 50 is attached to the first shell 10 through an appropriately located aperture 42 by a release fastener 52 such as a bumper fascia retainer, part number 12571, manufactured by AV-EE-Co, Cold Springs, Ky., (as shown in FIG. 16) commonly used in the automotive industry to attach door panels. Other fasteners would also work such as which will pull out when a sudden breakaway force between approximately 15-30 pounds is applied to the safety stilt 100 in the event of a fall are also contemplated by and therefore within the scope of the invention. The release fastener 52 releases the user's foot from the safety stilt 100, giving the user a greatly increased chance of landing safely on his/her feet as opposed to falling down from an elevated height with the stilts firmly and unreleasably attached. The foot strap assembly 50 is provided with fastening means (not shown) for attaching the outside foot strap half 50a and inside foot strap half 50b to each other to adjustably accommodate various sized feet. Suitable fastening mechanisms include but are not limited to hook and loop fastening material, buckles, snaps, and laces. In the embodiment where hook and loop fastener is used, a breakaway force of approximately 35 to 40 pounds per square inch is sufficient. It should be mentioned that the first shell 10 can be used by itself in instances where the extra height provided by the first shell 10 alone is sufficient and no variable height adjustment is needed.

FIG. 6 shows a perspective view of the second shell 70 of the safety stilt 100 of the present invention. It is seen that the second shell 70 defines a vertical axis 72 and a horizontal axis 74 as well as a top surface 76 and a wall 78 which supports and vertically separates the top surface 76 from a base 80. The top surface 76 defines a plane that is substantially parallel with a plane defined by the perimeter of the base 80 as it contacts the floor or other supporting surface. The surface area defined and enclosed by the base 80 is greater than the surface area dimension defined by the top surface 76, which enables the second shell 70 to slidably fit into upwardly tapering first shell 10. In one embodiment (not shown), a rib 82 substantially the length of the vertical axis 72 extends in a substantially tapered manner from the base 80 to the top surface 76 and runs parallel with the vertical axis 72. In other embodiments, as shown in FIGS. 6-8, and 10-14, a plurality of ribs 82 is provided to enhance the overall strength and assembled rigidity of the safety stilt 100, without substantially increasing the weight of the safety stilt 100. FIGS. 7A-7B are cross sections taken through the lines 7A-7A and 7B-7B of FIG. 7 respectively and show that a hollow space 84 is formed behind and corresponds in position with the rib 82 which extends from and is part of the wall 78. The hollow space 84 of the second shell 70 is sized and located to slidably receive the rib 22 of the first shell 10, thereby providing enhanced stability and rigidity to the assembled stilt 100. It is understood and therefore within the scope of the invention, that in another embodiment (not shown) the safety stilt will also work without any ribs configured into the wall 78. FIG. 7 shows a first side view (from the wider side—unnumbered) of the second shell 70. FIG. 8 shows a second side view (from the narrower or end side—unnumbered) of the second shell 70. In one embodiment, as shown in FIGS. 6 and 7, the base 80 is provided with a widened lip 81 surrounding its perimeter which strengthens the base 80, contacts the floor or support surface and adds extra stability due to an increased perimeter defined by the base 80. While no ribs (not shown this view) are shown on the end (unnumbered) shown in FIG. 8, it is contemplated by and therefore within the scope of the invention to have a rib 82 or ribs 82 on this end also. FIG. 9 shows a top view of the second shell 70 including the top surface 76. FIG. 10 shows a bottom view of the second shell 70 including the perimeter of the base 80 which contacts the floor or other surface while the safety stilt 100 is being used.

An advantage of the stilts 100 of the present invention is that the first shell 10 and second shell 70 are substantially identical prior to attachment of the foot strap assembly 50 and can thus be made from the same mold. Injection molds are extremely expensive to have built, in some cases costing several hundred thousand dollars each, which facilitates a great manufacturing cost savings. As shown in FIGS. 11-13, the first shell 10 is slidably fitted over the second shell 70 to create the safety stilt 100 of the present invention.

Materials used to construct the first 10 and second 70 shells include, but are not limited to high density polyethylene such as that sold under the trade name of Fortiflex® and manufactured by Ineos Polyolefins. Other plastic materials would work equally well and are therefore within the scope of the invention. A wall 18, 78 thickness range of ⅛″ to ¼ inch is sufficiently strong to be able to support a worker's weight of at least 250 lbs without adding unnecessary weight. In one embodiment, the shells 10, 70 are made by injection molding, followed by trimming and creation of a plurality of at least one column of height adjustment apertures 40 parallel with the vertical axes 12, 72, however, the height adjustment apertures 40 and foot strap apertures 42 can also be formed as part of the molding process. Foot strap apertures 42 are located proximate the top surface 16 of the first shell 10 and can be created by a cutting or drilling process or as part of the molding process. It should be mentioned that in one embodiment as shown in FIG. 15, four foot strap apertures 42 are provided to allow attachment of two foot strap assemblies 50 (front and back) should the user desire additional foot securement. The release fasteners 52 attaching the foot strap assembly 50 to the first shell 10 can be made of nylon or other plastic materials. The foot strap assembly 50 can be made of nylon backed hook and loop fastening material or leather backed hook and loop fastening material. The bolt 54a and nut 54b that are used to attach the first shell 10 to the second shell 70 and adjust their relative position, can be made of suitable non-conductive materials such as nylon or other plastics. In one embodiment, the height adjustment apertures 40 are configured to be square to be able to accommodate the square configured underside of the head of a carriage bolt (not shown), which as the advantage of not requiring an additional wrench to tighten the nut 54b on the other side.

Use

Using the safety stilt 100 involves first determining the height of the surface to be worked on (the workspace). The workspace height is factored with the height and working preferences of the user to determine the degree of height adjustment of the safety stilt 100. Presumably two safety stilts will be used (one for each foot of the user). The desired height is set by inserting a bolt 54a through the appropriate height adjustment aperture 40 followed by securing the bolt 54a with a non-insulating nut 54b on the inside of the safety stilt 100. Depending on the particular configuration of the first 10 and second 70 shells, a plurality of bolts 54a and nuts 54b may be used to set the desired height of the safety stilt 100. Because of the taper between the top surface 16, 76 and base 20, 80, the top surface 76 of the second shell 70 is able to slide within the open base 20 of the first shell 10 to create a variety of possible adjustment heights. In one embodiment, the first 10 and second 70 shells are approximately 31 inches high, between the base 20, 80 and the top surface 16, 76 respectively. Height adjustment apertures 40 can be located at any interval and in one embodiment are spaced about three inches apart.

Upon properly adjusting the height of the individual safety stilts 100 the user steps on to the top surface 16 and after ensuring that the user's heel is proximate the heel end 28 of the raised ridge 26, securely fastens the foot strap assemblies 50a, 50b together to stably attach the user's foot to the safety stilt 100. Should the user fall during use, one or more release fastener 42 attaching the foot strap assembly 50 to the first shell 10 will pull out, allowing the user to safely land on his/her feet as opposed to falling from the height of the still attached stilts 100. In the event that the safety stilt 100 releases during use, a new release fastener 42 should be used to reattach the foot strap assembly 50 to the first shell 10. This is because the original release fastener 42 may have become damaged as a result of releasing under force and could be unable to provide the specified amount of release force required for additional releases.

Claims

1. A safety stilt, comprising:

a. a first shell defining a vertical axis and a horizontal axis, a top surface and a base, the top surface having a lesser surface area than an area defined by the base;

b. a second shell defining a vertical axis and a horizontal axis, a top surface and a base, the top surface having a lesser surface area than an area defined by the base, wherein the top surface of the second shell is sized and shaped to be slidably received within the base of the first shell, allowing the second shell to move along the vertical axis of the first shell;

c. height adjustment means allowing the relative position between the first shell and the second shell along the vertical axis to be securely adjusted; and

d. releasable foot attachment means attached to the first shell allowing a user's foot to be secured to the top surface, wherein the foot attachment means will release from the safety stilt if the user falls.

2. The safety stilt of claim 1 wherein the first shell and second shell are substantially identical.

3. The safety stilt of claim 1 wherein a raised ridge extends above the top surface of the first shell.

4. The safety stilt of claim 4 wherein the raised ridge extends partially around the top surface of the first shell.

5. The safety stilt of claim 4 wherein the raised ridge extends around a heel end and around both sides, terminating before a toe end of the first shell.

6. The safety stilt of claim 1 wherein a plane defined by the base is substantially parallel with the plane defined by the top surface.

7. The safety stilt of claim 1 wherein the height adjustment means comprise spaced apertures through the first shell and the second shell, capable of receiving a securing fastener there through.

8. The safety stilt of claim 1 wherein the releasable foot attachment means comprise a strap assembly attached to the first shell by a release fastener.

9. The safety stilt of claim 1 wherein the first shell and second shell are made of a non-conducting material.

10. The safety stilt of claim 9 wherein the first shell and second shell are made of a plastic material.

11. The safety stilt of claim 1 wherein a wall extends between and vertically separates and supports the top surface from the base.

12. The safety stilt of claim 11 wherein the wall surrounds and extends between the top surface and the base.

13. A safety stilt, comprising:

a. a first shell defining a vertical axis and a horizontal axis, a top surface and a base, the top surface having a lesser surface area than an area defined by the base, and a wall extending between and connecting the top surface and the base;

b. a second shell defining a vertical axis and a horizontal axis, a top surface and a base, the top surface having a lesser surface area than an area defined by the base and a wall extending between and connecting the top surface and the base, wherein the second shell is sized and shaped to be slidably received within the base of the first shell, allowing the top surface of the second shell to move along the vertical axis of the first shell;

c. a rib defining an outer surface, extending away from the wall of the first shell and a rib defining an outer surface, extending away from the wall of the second shell, the rib of the first shell further defining an inner surface corresponding with the outer surface such that the outer surface of the rib of the second shell slidably mates with the inner surface of the rib of the first shell;

d. height adjustment means allowing the relative position between the first shell and the second shell along the vertical axes of the first and second shells to be securely adjusted; and

e. releasable foot attachment means attached to the first shell, allowing a user's foot to be secured to the top surface, which will release from the safety stilt if the user falls.

14. The safety stilt of claim 13 wherein the first shell and the second shell are made of a non-conducting material.

15. The safety stilt of claim 14 wherein the first shell and the second shell are made of plastic.

16. The safety stilt of claim 13 wherein the first shell and second shell are substantially identical.

17. The safety stilt of claim 13 wherein a raised ridge extends above the top surface of the first shell.

18. The safety stilt of claim 17 wherein the raised ridge extends partially around the top surface of the first shell.

19. The safety stilt of claim 18 wherein the raised ridge extends around a heel end and around both sides, terminating before a toe end of the first shell.

20. The safety stilt of claim 13 wherein a plane defined by a perimeter of the base of the second shell is substantially parallel with a plane defined by the top surface of the first shell when the first shell and the second shell are assembled to form the safety stilt.

21. The safety stilt of claim 13 wherein the height adjustment means of the first and second shells comprises spaced apertures capable of receiving a securing fastener there through.

22. The safety stilt of claim 13 wherein the releasable foot attachment means comprise a strap attached to the first shell by a release fastener.

23. The safety stilt of claim 13 wherein the wall substantially surrounds and extends between the top surface and the base.

24. The safety stilt of claim 23 wherein the wall of the first shell tapers outward between the perimeter of the top surface and the base and the wall of the second shell tapers outward between the perimeter of the top surface and the base.