US 2923947 A
Abstract available in
Claims available in
Description (OCR text may contain errors)
Feb. 9, 1960 F. T. WEIGHILL HYDRAULIC STILT 2 Sheets-Sheet 1 Filed Feb. 3, 1958 INVENTOR finned: Z l/ez' li l Filed Feb. 3, 1958 2 Sheets-Sheet 2 24 mum Z INVENTOR ATTOR EY- United Statesy Patenr O 2,923,941 HYDRAULIC ISTILT l. I T. Weighill,Port Hueneme', Calif.
*Applicationllfehruary a, 1958, Serial No. 712,960 a 4cm. cm-4) This invention relates-to stilts and more particularly to hydraulically operated adjustable stilts.
The use of stilts for picking lemons and other fruit, in building construction, and for work on aircraft has obvious advantages but the stilts known in the prior art do not meet the requirements of being safe and readily and easily adjustable up and down, and having a wide range of positions. In the instant invention, a hydraulic mechanism actuated by the leg movements of the wearer is utilized in conjunction with a plurality of telescoping cylinders and a valve system for efliciently and positively adjusting stilt heights to any desired position.
An object of this invention is to provide a simple, eflicient, easily adjustable, hydraulic stilt.
An additional object is to provide a compact hydraulic mechanism in which the user brings about stilt elongation by leg movements.
Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following description.
Fig. 1 is a perspective view of a man wearing stilts embodying the invention;
Fig. 2 is a view, partly in section, of one of the stilts shown in Fig. l in the extended position; and
Fig. 3 is a view, partly in section, of the stilt shown in Fig. 2 in the closed position.
As shown in the three views, the stilt is made up of a base plate 10, which may take'any one of numerous possible configurations, a first telescoping member 12, a second telescoping member 14, a third telescoping member 16, and cylinder 18. Outer casing 20 fits around cylinder l8 and is provided with a foot rest 22 with its restraining strap 23 and with strap 24 for securing the stilt to the leg of the wearer. Cylinder 18, by means of bracket 25, also supports supply tank 26 which has a filler cap 27. Casing 20 is provided with openings 28 so that the various connections to tank 26 do not interfere with the movement of casing 20 relative to cylinder 18. Projections 29 on the telescoping members limit the safe travel of the component parts as stilt length is decreased. It will be understood that any desired number of telescoping members may be used; the drawings show three stages.
Referring specifically to Figs. 2 and 3, a piston 30 is secured to casing 20 by means of rod 32 and nut 34. Piston 30 moves up and down in chamber 36 in cylinder 18. The variable space below piston 30 is vented to the atmosphere through opening 38, and the variable space above piston 30 communicates with supply tank 26 through tubing 40 containing check valve 42 and with chamber 44 through tubing 46 containing check valve 48. The space above piston 30 in chamber 36 is sealed by means of packing 50 and packing nut 52 to prevent leakage of hydraulic fluid around rod 32. Chamber 44 is connected to tank 26 through tubing 54 containing valve sfi which is adapted to be opened and closed by the wearer. Spring 58 biases outer casing 20 away from cylinder 18, and locking lever'60 serves to lock outer casing 20 to cylinder 18 when the stilt is to be maintained at a fixed height. The telescoping members are provided with O-ring seals 62 to prevent hydraulic fluid leakage and with internal stops 64 to limit outward travel of the component parts as stilt length is increased.
- In operation, the user secures the stilt to his person by-inserting his foot in the opening between strap 23 and footrest 22 and fastening straps 24 around the lower leg. With the'telescoping members fully retracted the foot of the wearer is only a short distance above ground level. Assuming that the user desires to lengthen the stilt, valve 56 is closed and mechanical lock 60 is released. The weight ofthe wearer compresses springl58 thus allowing outer casing 20 to move relative to cylinder 18 causing a partial vacuum in chamber 36 and drawing fluid from tank 26 into chamber 36. The wearer then removes his weight from the stilt thus allowing spring 58 to drive piston 30 upwardly and thereby forcing fluid into the space above the telescoping members; the fluid is accommodated by the downward movement of the telescoping members which lengthens the distance between the wearers foot and the ground. By alternately applying and releasing body weight to the two stilts in turn, an operator quickly raises himself to the desired height. The simple walking motion used for actuating the stilt lengthening mechanism is easily learned and controlled. It will be noted that the application of downward force by the wearer does not cause the stilt to elongate directly; the energy to carry out the elongation is stored in spring 58 until the spring is released. The release of the spring occurs when the operators weight is substantially all on the other stilt so that the elongation of the telescoped cylinders meets with little resistance. The operator is not working against himself to elevate his person as is the case with hydraulic schemes known in the prior art. With three compact telescoping members as shown in the drawings an operator can easily raise himself six feet above the ground. With additional extending members it is practical to reach considerably greater heights.
To maintain any desired position, the operator simply locks casing 20 to cylinder 18 by means of mechanical lock 60. The fluid above the telescoping members can not go back to the source tank through check valve 48, and valve 56 is closed so the members remain at a fixed level. When the operator desires to lower himself, valve 56 is opened thus allowing fluid to pass into tank 26 and directly shortening the stilt by the action of his own weight.
Obviously, many modifications and variations of the present invention are possible in the light of the above teachings. For example, a valve placed in tubing 40 would eflectively lock the stilt raising mechanism when closed and would eliminate the need for mechanical lock 60. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.
What is claimed is:
l. A hydraulic stilt comprising a casing, a cylinder slidably engaging said casing and defining first and second fluid receiving chambers, a piston secured to said casing and engaging in fluid tight relation the walls of said first fluid receiving chamber to define a work space, resilient means connected effective to bias said casing rela' tive to said cylinder, a hydraulic fluid source, a first tubing connecting said source with said working space, a check valve disposed in said first tubing and adapted to prevent the fiow of hydraulic fluid from said work space to said source, a second tubing connecting said work space with said second fluid receiving chamber, a check 3 valve disposed in said second tubing and adapted to prevent the flow of hydraulic fluid from said second fluid receiving chamber to said work space, a third tubing connecting said second fluid receiving chamber with said source, a valve disposed in said third tubing, locking means operable to prevent movement of said casing relative to said cylinder, a plurality of hydraulically actuated telescoping members operably connected to said second fluid receiving chamber, and attaching means for attaching said casing to the wearer of the stilt.
2. In a hydraulic stilt worn by a user, mechanical means for storing energy derived by the downward application of the weightof the user, a hydraulic cylinder connected to said mechanical means and actuated by release of the stored energy in said mechanical means to generate a positive fluid pressure, and telescoping members operatively connected to said hydraulic cylinder effective to be extended by the pressure generated in said hydraulic cylinder.
. 3. In a hydraulically operated stilt, a hydraulic motor 20 2,351,145
comprising a spring for the storage of encrgy, a piston, a cylinder adapted to receive said piston;'a source of-hydraulic fluid, atleast one extendable stilt member, a footrest operatively connected to compress said spring, a first pipe effective to connect saidsource of hydraulic fluid to the work space in said cylinder above said piston, a second pipe effective to connect said work space to said extendable stilt member, means connecting said spring to said piston, and valve means for controlling the direction of fluid flow in said first and second pipes.
4. An adjustable stilt comprising hydraulically actuated telescoping members, a source of hydraulicfiuid, a spring, a hydraulic motor driven by 'saidspringand connected elfective to supply hydraulic fluid from said source under pressure to said telescoping members, and means for compressing said spring to impart energy thereto.
References Cited in the tile of this patent UNITED STATES PATENTS Pearson June 13, 1944