Stilt devices enable a workman to perform work at an elevated height above a base surface. Such devices are often used in the construction industry to facilitate operations several feet above the ground or floor level which would not otherwise be reachable without a scaffold, ladder or other support structure.
A number of useful stilt devices are known in the art, such as taught in U.S. Pat. Nos. 3,902,199 and 7,108,640, assigned to the assignee of the present application. Such stilts may be configured to be adjustable in height over a selected range through the use of telescopic struts. Different models of stilts can further be used to provide different ranges of adjustability. For example, one model of stilts may be provided that can be incrementally adjusted from a lower height of 12 inches to an upper height of 24 inches, whereas a different model of stilts may accommodate increments of from 24 to 40 inches, etc.
The types of elements employed in these respective types of stilt models may be similar, in that various models may all have shoe plates, floor plates, leg attachment assemblies and so on, each model may nevertheless have different mechanical configurations to accommodate different heights (and different height adjustment ranges). This can present difficulties in providing adequate adjustment ranges and other characteristics for the various models.
The present invention provides preferred embodiments of an improved stilt device for supporting a workman at a selected working elevation above a base support surface. The stilt device has a first extendible strut having a first member and a cooperating first extension member that has one end extending into the first member. A second extendible strut in like manner has a second member and a cooperating second extension member that has one end extending into the second member. These members are disposed in parallelogram relationship with a base plate and a shoe plate, each of which is pivotally connected to opposing ends of the first and second extendible struts.
A damping assembly is connected between the first and second extendible struts and serves to bias these members to assume upright positions. A leg attachment assembly extends from proximity of the lower leg of the workman and has a leg support pole connected to the second member, and with attachment to the leg, stabilizing the workman and providing the capability of altering the range of elevation by replacement with other selected lengths of the extension members.
In one preferred embodiment, wherein the stilt has an increased height, a damping assembly is provided having an adjustable upper spring for forward walking motion and an adjustable lower spring for rearward walking motion, the upper spring is selectively constructed to operate to a force range of about 70 to 120 lbs. and the lower spring is selectively constructed to operate to a force range of about 40 to 80 lbs.
Further, the leg support pole preferably supports a leg clamp that has a pair of curved leg plates and a fastener strap for attaching the upper end of the leg support pole to the leg. Further, a medial portion of the leg support pole is adjustably attached to the shoe plate.
These and various other features and advantages which characterize the claimed invention will be apparent from a reading of the following detailed description and a review of the associated drawings.
Numerous possible variations and modifications will readily occur to the skilled artisan upon a review of the following discussion. Thus, it will be understood that the various exemplary embodiments disclosed herein are illustrative of, and are not limiting to, the scope of the invention.
The front extendible strut 108 and the rear extendible strut 110 are preferably telescoping assemblies that permit selective adjustment to their lengths, and thus, to the height that a pair of the stilt devices 100 will elevate the wearing user. A plurality of axially aligned holes are provided in the extendible struts 108, 110, and fasteners 111 can be positioned in selected ones of such holes, allowing the user to selectively adjust and fix the lengths of the struts 108, 110, thereby determining the height of the shoe plate 102 above the base support surface 101. Furthermore, as will be discussed below, the stilt device 100 can be assembled with varying lengths of the extendible struts 108, 110 to change the range of heights to be served by different models of stilt devices 100, changing the range of elevation capability.
Continuing with the description of the stilt device 100, a damping assembly 112 interconnects the front and rear extendible struts 108, 110 to position the extendible struts 108, 110 in the parallelogram relationship depicted in
The damping assembly 112, in addition to maintaining the parallelogram relationship of the extendible struts 108, 110, provides flexibility and cushioning to the user by permitting limited forward and rearward pivoting of the extendible struts 108, 110 with respect to the shoe plate 102 and the base member 104 as user walking or other leg movement occurs. With the exceptions described herein below with regard to attachment to the upper and lower extendible struts 108, 110, and for the exceptional stilt heights described herein below, the damping assembly 112 operates in the same manner described in my U.S. Pat. Nos. 3,902,199 and 7,108,640, which are incorporated herein by reference.
A leg attachment assembly 120 has a telescopic leg support pole 122 that can be adjusted as desired to properly fit the user's leg length. The leg support pole 122 includes an inner sleeve 124 and an outer sleeve 126, with the lower end of the inner sleeve 124 attached to the rear extendible strut 110 by connector member 128 (see
As shown in
A curved second leg plate 140 is disposed in facing relation to the first leg plate 134 and is pivotally connected thereto via a hinge pin 142. A biasing spring 143 may be provided to bias the second leg plate 140 to the closed position depicted in
The support attachment assembly 132, as shown in
The shoe plate 102 is pivotally attached to the upper ends of the extendible struts 108, 110 by extendible strut attaching brackets 162 and hinge pins 162A, and the shoe plate 102 is pivotally attached to the base members 104 by extendible strut attaching brackets 164 and hinge pins 164A. These four components—the parallel extendible struts 108, 110 and parallel shoe plate 102 and base member 104—are retained in parallelogram relationship as they pivot together.
The front and rear extendible struts 108, 110 serve as adjustable length legs for the stilt device 100. Each of the front extendible strut and the rear extendible struts 108, 110 is an extendible assembly. The front extendible strut 108 has an upper member 108A and a lower extension member 108B. The upper member 108A is an elongated outer sleeve member that is pivotally secured at its upper end to the shoe plate 102. The lower extension member 108B is an elongated member having its upper end disposed, and reciprocally slidable, within the upper member 108A. In like manner, the rear extendible strut 110 has an upper member 110A and a lower extension member 110B. The upper member 110A is an elongated outer sleeve member that is pivotally secured at its upper end to the shoe plate 102. The lower extension member 110B is an elongated member having its upper end disposed, and reciprocally slidable, within the upper member 110A. The lower ends, that is, the free ends, of the extension member 108B and 110B are pivotally connected to the base member 104.
Each of the extendible extension members 108B and 110B has several hole sets, any one set of which can be axially aligned with a set of axially aligned holes in the engaged member (108A, 110A) for receipt of a fastener 111 to rigidly establish the lengths of the extendible struts 108, 110. Preferably, the members 108A, 110A and the extension members 108B, 110B are shaped to have a circular or oval cross-section, but any selected cross-section shape will suffice as long as the cross-section shape and dimension of these members are correspondingly selected so that they can operate as extendible assemblies.
Returning attention to the leg attachment assembly 120, it will be noted that the connector member 128 is attached to the rear extendible strut 110 by means of a non-capturing yoke bracket 170 that is shown in enlarged detail in
An upper portion 129 of the connector member 128 extends into the lower end of the inner sleeve 124 and is attached thereto by bolts (not shown). Of course, it will be recognized that the lower end of the inner sleeve 124 can be swaged to be formed into the shape of the connector 128 so that the connector is an integral portion of the inner sleeve 124. Fastener members 180 extend through apertures (not separately numbered) in the base member 174 and extend into appropriately positioned apertures 182 in the member 110A to attach the bracket 170 thereto.
The flush or slightly recessed mounting of all fasteners that penetrate the walls of the extendible struts 108, 110, such as the above described fasteners 182 (with exception of the fasteners 111), is desirable, as this provides unimpeded sliding access for the extension members 108B, 110B along the full lengths of the members 108A, 110A.
With reference to
Turning now to
It will be noted that in each of the stilt devices 100, 100A and 100B, the attachment of the bracket 170 to the supporting rear extendible strut 110 is the same distance L1. That is, as with the stilt device 100, the bracket 170 for the stilt device 100A is attached to the rear extendible strut 110A at the distance L1 as measured from the bracket 160, and the bracket 170 for the stilt device 100B is attached to the rear extendible strut 110A″ at the distance L1 measured from the bracket 160.
The point to note is that the lengths of the front and rear extendible struts 108, 110 are different in each of the stilt devices 100, 100A and 100B, but the attaching point of the bracket 170 is at the same distance L1 below the bracket 160. With the exceptions to be described, the components of the stilt devices 100, 100A and 100B are identical and interchangeable. The only differences between the three stilt devices 100, 100A and 100B are the lengths of the struts 108, 108′, 108″ and struts 110, 110′, 110″, respectively. Thus, in each of the stilt devices the lengths of the front and rear extendible struts is adjustable within a range of extension that is determined by the lengths of the component members thereof. This is a valuable feature of the present invention, as this permits the stilt devices to serve different elevation ranges for the workman who will be wearing the stilt devices.
In addition to the capability of altering the range of height extension for the embodiments of the present invention, the present invention provides the capability of standardization of component parts. The advantage of component standardization is that the leg support pole 122 is attached to the stilt extendible strut at a distance below the shoe plate 102 that can be the same for all sizes of stilts. Thus, the inner and outer sleeves 124, 126 are the same length for all stilt heights. This provides substantial weight and material savings on taller, normally heavier stilt sizes. Also, the in and out adjustment of the side leg support and the leg band is consistent for the stilts. Before the present invention, all stilt side leg supports and leg bands had diminishing in and out (lateral) comfort adjustment as the stilt sizes became taller because the side leg support lower connection was referenced from the bottom of the stilts.
A benefit of the stilt device of the present invention, in which the spring brackets, actuator bracket, and spring assemblies are referenced from the approximate same distance from the shoe plate for all sizes (heights) of stilts, is that the same tooling can be used to perforate bracket holes in the support extendible struts and attaching brackets for the stilts. Also, the weight of brackets and spring mechanism are disposed higher on stilts, yielding a higher center of gravity on taller stilts. Thus, there is less lever arm weight leverage to the legs of the wearing workman while walking.
A further benefit of the embodiments of the present invention, compared to prior art stilts, is that the front and rear extendible struts are circular, oval or otherwise of symmetrical cross section, and the rivets or fastening means that secure the brackets 170 to the extendible struts are flush with, or recessed from, the inside surface of the members 108A. Thus, the extension members 108B, 110B need not have a cross section with a clearance profile, such as a continuous longitudinal groove, to allow the free passage of the extension members 108B, 110B along the entire length of the members 108A, 110A. This allows the inner extension members to pass by the bracket connections without being restricted by the fasteners. The weight of the front and rear extendible struts 108, 110 are reduced since there is no need for a longitudinal rivet channel, which reduces the cross-sectional area.
Also by making the inside of the members 108A, 110A smooth and free of protrusions or rivet projections, the extension members 108B, 110B can have the same profile and be just enough smaller to slidably fit into the outer members 108A, 110A with just a very thin sleeve or bearing gap clearance. By making both outer and inside members of the same profile shape with the inside member just a material thickness plus a thin sleeve smaller, extendible strut construction is more efficient and lighter, while retaining adequate strength, than in the past. Also, by making it possible to have the inside adjustment tube the same profile shape but just smaller it becomes much easier to swage or expand one end and to fit the same end bracket as the larger outer tube and therefore use only one size end bracket to fit all leg ends.
In illustration of the above,
It will be appreciated from a review of
Thus, as mentioned, the inner tubular extension members need not have a cross section with a clearance profile, such as a continuous longitudinal groove, to allow the free passage of the tubular extension members along the entire length of the tubular members. This allows the inner tubular extension members to pass by the bracket connections without being restricted by the fasteners.
Also by making the inside of the tubular members 108A, 110A smooth and free of protrusions or rivet projections, the tubular extension members 108B, 110B can have the same profile and be just enough smaller to slidably fit into the outer tubular members 108A, 110A with just a very thin sleeve or bearing gap clearance. By making both outer and inside tubular members of the same profile shape with the inside tubular member just a material thickness plus a thin sleeve smaller, extendible strut construction is more efficient and lighter, while retaining adequate strength, than in the past. And, as mentioned above, by making the inside adjustment tube the same profile shape but just smaller, it is easier to expand one end and to fit the same end bracket as the larger outer tube and to use a one size end bracket to fit all leg ends.
It will also be noted that an advantage of the oval curvilinear members (such as 202, 204 in
One feature of the embodiments of the present invention is that of permitting the making of stilts for much greater heights than has heretofore been practical. Such greater heights are needed in such instances as that of building structures and of other applications requiring greater workman floor reach. For example, as the height of ceilings have increased with the changes in style and construction trends, there has been a need for taller articulating leg extension devices to service the needs of such construction. Also, certain segments of the horticultural industry have been needing taller stilts in order to harvest some crops, such as rack supported tomato plants.
Heretofore taller stilts have not been practical due to weight, security, comfort and function considerations. Comfort and security have been addressed in my U.S. Pat. No. 7,108,640. The embodiments described herein above, in addition to the features previously recognized herein, relate to improved weight and function and make utilization of taller articulating leg extension stilts practical.
The prior articulating leg extension stilt art utilized damping springs (such as the upper and lower damping springs 114, 116 described herein above) that were virtually the same for the forward motion and rearward motion of the stilt, although it was recognized that a more natural feeling of stilt walking was achieved by stiffening the upper spring over that of the lower spring.
It has been found that taller articulating stilts require springs that are distinctly different in that it is required that both the upper and lower springs of the damping assembly are not only stronger (stiffer) but that there is a decidedly different force and length requirement for the forward motion upper spring than the rearward motion lower spring. For safety and function, the utilization of taller stilts require that the forward motion upper spring be longer and appreciably stronger than the lower spring.
For an articulating leg extension stilt operating in the required height range of between 33 inches to 64 inches having a damping assembly incorporating an adjustable upper spring for forward motion and an adjustable second lower spring for rearward motion, the upper spring preferably operates to a compressing force range of about 70 to 120 pounds and the lower spring preferably operates to a force range of about 40 to 80 pounds.
The upper and lower springs of the damping assembly have usually been made from stainless steel extruded music wire, the upper spring wire having a diameter of about 0.115 inch and the lower spring wire having a diameter of about 0.110 inch. For the taller stilts with a height range of between 33 inches to 64 inches, these dimensions are preferably increased so that the upper spring wire has a diameter of about 0.145 inch and the lower spring wire having a diameter of about 0.125 inch.
These and various other features and alternatives will readily occur to the skilled artisan in view of the foregoing discussion.
It is to be understood that even though numerous characteristics and advantages of various embodiments of the present invention have been set forth in the foregoing description, together with details of the structure and function of various embodiments of the invention, this detailed description is illustrative only, and changes may be made in detail, especially in matters of structure and arrangements of parts within the principles of the present invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.