US2802217A

US2802217A - Leg extension device

Info

Publication number: US2802217A
Application number: US544156A
Authority: US
Inventors: Howard J Wilhoyte
Original assignee: Individual
Current assignee: Individual
Priority date: 1955-11-01
Filing date: 1955-11-01
Publication date: 1957-08-13
Anticipated expiration: 1974-08-13

Description

Allg- 13, 1957 H. J. wlLHoYTE LEG EXTENSION DEVICE 2 Sheets-Sheet l Filed NOV. l, 1955 INVENTQR. /owam/ M/hoyfe Aug. 13, 1957 H. J. wlLHoY'n-z 2,802,217

LEG EXTENSION'DEVICE Filed NOV. l, 1955 2 Sheets-Sheet 2 INVENTOR. 76am# /W/og/f? United rates Patent LEG EXTENSION DEVICE Howard J. Wilhoyte, Lafayette, Ind.

Application November 1, 1955, Serial No. 544,156

` V11 claims. (ci. 3 4) This invention relates to a leg extension device, and is adapted particularly for use by persons whose work or trade involves overhead construction, application or inspection, which would ordinarily require the use of a scaffold or elevated platform for efiicient performance. The device is intended to elevate the user a suicient distance above ground or floor level, to bring the users hands and line of vision into close proximity with overhead work to be performed, without limiting free mobility over the oor, ground, or other supporting surface. In this respect, the device when applied to the users leg and foot, presents meritorious advantages over the common fixed scaffold, elevated platform or ladder generally employed under the circumstances mentioned. Although the leg extension device is suited for use by tradesmen as above stated, the use is not to be thusly limited, for as will readily be understood the device might as well be used for entertainment purposes, the picking of fruit, or any of a number of pursuits wherein the height of the human body is to be extended.

An object of the invention is to provide a leg extension device for the purposes stated, which is simple, inexpensive, and light of weight. g

Another object is to provide such a device embodying advanced structural features, which ensure safe and effective manipulation on the part of the user, without fatigue and exertion tending to tire the user.

A further object is to incorporate in the leg exten-sion device a system of articulated links and members yieldingly biased in a particular manner, to produce what may be considered a supplemental ankle joint, so designed and arranged as to impart a natural foot and leg movement devoid of stiffness or inflexibility conducive of fatigue.

Another object is to incorporate in a device of the character stated, means to compensate or adjust for the weight of the user,'in the interest of comfort in use by various types of individuals.

The foregoing and other objects are attained by the means described herein and illustrated upon the accompanying drawings, in which:

Fig. l is a side elevational View of a basic form of the leg extension device, showing the manner of application to the foot and leg of a user supported upon the device.

Fig. 2 is a side elevational View, parts broken away in the interest of clarity of illustration, showing a preferred form of the device.

Fig. 3 is a perspective View of 'an-adjustable spring seat, constituting a detail of the invention.

Fig. 4 is a cross-sectional view taken on line 4 4 of Fig. 2.

Fig. 5 is a perspective view of an equalizer lever, forming a part of the invention.

With reference to the simplified form of the device as illustrated by Fig. 1, the character 6 indicates a shoe pad upon which is superposed the shoe 7 of the user. Directly beneath the pad, and spaced therefrom in substantial parallelism, is the foot member 8 which is adapted to bear upon the lloor or other surface to be traversed in walking. The shoe pad and the foot member are maintained in the spaced relationship illustrated, by means of front and rear

upright struts

9 and 10, respectively. Applied to the lower ends 12 of the struts are the hinges 13, which serve to pivot the struts upon the foot member 9, so that the struts may lean forwardly or rearwardly at various angles to the mean plane of the foot member. The upper ends 14 of the struts are connected to the under face of the shoe pad 6 by means of hinges 15 and 16, which likewise permit the struts to lean and change their angular relationship to the mean plane of the shoe pad. foot member normally form a right parallelogram the corners of which may change in angularity as the shoe pad is shifted forwardly or rearwardly relative to the foot member 8.

A stabilizer or post 17 has an upper end 18 provided with a band or clamp element 19 for embracing the leg of the user, and the lower end portion 20 of this stabilizer may be fixed securely to the rear strut 10, so that the strut and the :stabilizer will move and lean in unison as the wearer uses his foot and leg to manipulate the device. The height of the stabilizer may be limited, if desired, to the height of the shoe 7, and may then have its upper end secured to the side of the shoe above the heel 21, as will be understood. The shoe may or may not be xedly mounted upon the pad 6.

By preference, though not of necessity, means may be provided in association with the struts, to yieldingly resist forward and rearward leaning of the struts from the normal vertical position relative to the foot member 8. Such means may comprise a pair of

equalizer springs

22 and 23 having inner ends anchored at 24 to a xed and rigid bracket 25, while the outer ends of the springs are anchored as at 26 to the

struts

9 and 10 intermediate the ends of the struts. The bracket 25 may be fixed to the'under surface of the shoe pad 6 as shown, or as an obvious alternative, it may with equal effectiveness and purpose be fixed in upstanding position upon the top face 27 of the foot member. In either case, the springs will serve always to bias the struts toward the vertical position.

Thus, in the act of walking there will be a resilient force induced by the

springs

22 and 23, countering any tendency of the struts to lean ,forwardly or rearwardly. This actiony of the struts is natural to the movement of the foot in walking, and in cooperation with the bias of the springs there is achieved a motion simulating ankle movement and limitation, which is natural and comfortable to the user of the device. By reason of this arrangement of parts, the device of the invention may be worn for extended periods of time without subjecting the user to discomfort and fatigue.

To further improve the efliciency and comfort of the device, the rearward spring 23 may be made heavier or more resistant to stretching than the forward spring 22, so as to more forcefully resist the forward leaning of the struts. In the case of Fig. l, both springs are tension springs as will be understood. In Figs. 2 to 5, the same spring action is obtained with the use of compression springs, and in addition the spring is rendered adjustable to compensate for differences in the weight or other characteristics of the user. Thus there is suggested also the adjustability feature for the Fig. 1 version of the device, if maximum comfort and efficiency are considered sufciently important in the simplied structure of Fig. l.

In principle, the device of Figs. 2 to 5 is similar to Fig. 1 as above described. Referring to Fig. 2, 30 is the shoe pad and 31 indicates the foot member. Upstanding upon the foot member is a seriesof perforated lugs 32 to which Patented Aug. 13, 1957` In other words, the struts, the shoe pad, and thel are pivoted the forward upright struts 33 and the rear struts 34. The pivots are indicated `at 35, and may be in the form of bolts, screws, rivets or other types of fasteners. The character 36 indicates one or more reinforcing ribs upstanding upon the foot member, which may bev of metal, wood, or other suitable material.

. Depending from the under face of the shoe pad 30 is a series of perfor-ate lugs 37, tok which are hinged the upper ends Of the

struts

33 and 34. Suitable pivot members 38 are employed for the purpose. The pivots and struts are so arranged relative to the shoe pad and the foot member as to form therewith a right parallelogram, which by shifting of the shoe pad forwardly and rearwardly, may be distorted to change the angles at the corners thereof. The distortion mentioned is opposed by spring force, as will be explained.

. As shown in Fig. 2, the struts 33--33 and 34-34 are preferably formed of angle members with inwardly projecting legs 39, and such legs of the forward struts 33-33 are spanned by plates such as 4t) and 41, secured to the struts for maintaining the latter in spaced parallelism at all times.

Similar plates

42 and 43 join and space the rearmost struts .3A- 34. The plates may be secured to the struts by means of rivets 44, screws, welds or `any other medium suitable for the purpose, and to impart added strength to the plates, an end thereof may be turned at an angle as indicated at 45.

The

uppermost plates

40 and 42 serve as stops or abutments for a pair of

equalizer levers

46 and 47, which may be in the form of bell cranks as illustrated by Fig. 5, wherein 48 and 49 constitute the arms arranged substantially at right angles to one another. Preferably but not necessarily, the bell crank may be a composite structure made up of two identical stamped plates of metal joined in spaced parallelism by means of spacing rivets t). Where the arms intersect, the bell crank lever may be provided with aligned openings 51 adapted to receive `a shaft or pin about which the lever may be rocked. With further reference to Fig. 5, attention is directed to the notch or socket 52 formed in the underside of the lever arm 4S, the function of which will be explained presently.

Referring now to Fig. 2, it may be noted that the bell crank lever 46 is quite similar to the lever 47, in that it includes a horizontal arm 53 notched at 54, a depending arm 55 corresponding to the arm 49, and an intermediate opening receptive of the pivot member 38 `whereby the bell crank lever may be rocked about the pivot member.

The primary difference between the bell crank levers 46k and 47, is in the location of the notches or

sockets

52 and 54. The notch or socket 54 of bell crank lever 46 is at a greater distance from its pivotal mounting, than is the notch 52 spaced from the pivotal mounting of lever 47. The arm 53, therefore, is longer than the arm 48, Fig. 2. lever 46 (Fig. 4), may be rather widely spaced apart by the spacers 5S, so that the corresponding plates of lever 47 may move between the plates 56-57 whenever the levers oscillate about their respective pivot members. rl`he oscillating or rocking of the

levers

46 and 47 is induced by the forward and rearward rocking of the

struts

33, 34 as the

equalizer lever arms

49 and 55 bear against the plates or

abutments

40 and 42, respectively.

'l he equalizer lever arms 49 and 5S may be held yieldingly against the

abutments

40 and 42 by means of the compression spring 59, the force of which may be adjustable through manipulation of the thumb nut 6i). The spring surrounds an eye bolt 6l threaded at one end to receive the nut 63 ns shown, whereas the remaining end of the bolt carries au eye 62 adapted to receive a screw 63 or other suspension means for the eye bolt.

A spring seat member 64, detailed in Fig. 3, transmits the force of spring 59 to the inner end portions of the

arms

53 and 48 at the

notches

54 and 52, as clearly shown in Fig. The member 64 may carry a pair of diametrally Varranged upstanding ribs 65 to engage the notches and The plates 56--57' constituting the bell crank` thereby preclude dislocation of the spring assembly relative to the bell crank equalizer arms. From the foregoing, it will be understood that any downward displacement of either arm 53 or 4S will be yieldingly resisted by the spring 59, to a degree dependent upon the adjustment of thumb nut 60 along the threaded end of the eye bolt 61.

By reason of lthe fact that the force of spring 59 is applied to lever arm 53 at a substantial distance from its fulcrum 38, any clockwise movement of the bell crank 46 will be quite strongly resisted by the spring. On the other hand, by reason of the shorter length of the arm 48 of bell crank 47, any countenclockwise movement of bell crank 47 will meet with a lesser degree of spring resistance. Accordingly, if the foot of the user is applied to the shoe pad 30 and manipulated to lean the pad and struts 33-34 forwardly, or to the right in Fig. 2, the abutment plate 42 bearing upon the arm 55 of bell crank 46 will lower the lever arm 53 against a substantial resistance set up by spring 59. Conversely, if the foot be manipulated to lean the pad 30 and struts 33-34 rearwardly, or to the left in Fig. 2, the other abutment will force the bell crank lever 47 into counterclockwise rotation about its pivot 38, causing the arm 48 to more easily compress the spring 59 due to the shorter length of said arm. As the result of these differential spring actions, the natural ankle movements of the user are simulated in the apparatus, enhancing comfort to the user and minimizing fatigue to a most extraordinary degree. Altering the force of spring 59 by means of the thumb nut 60, adjusts the device to the weight of individual users without altering the ratio of spring pressures acting upon the individual bell cranks.

To stabilize the device and provide the desired support for the users ankle, a post 67 of wood or other rigid material may be secured to one of the rearward struts 34, and extended upwardly above the shoe pad 30 as shown, so that by means of a band such as 68 the upper end of the post may be secured to the leg of the user in the manner illustrated by Fig. l. The band 68 may be of flexible strap material applied to a part-cylindrical socket member 69 of metal, plastic, or other suitable material, xed to the upper end of post 67 by means of screws 70 or other appropriate fastening devices. The

l flexible strap 68 may be furnished with a buckle or similar fastener, not shown, to hold the users leg in place within the socket member 69. If desired, the upper end of post 67 may be shortened somewhat, and provided with means for attaching same to the side of the shoe in the region of the heel cap, as was previously explained in the description of Fig. l.

The post 67 at its lower end 71 may be transversely drilled to receive the lower bolt or pivot member 35 of strut 34, thereby fixing the post relative to the strut at that point. At an intermediate point on the post, a hole 72 may be provided for reception of the upper bolt or pivot member 38 for strut 34, thereby to anchor the post relative to the strut in the region of the shoe pad 30. A spacer 73 (Fig. 4) may be provided about the upper bolt 38, between the post 67 andthe adjacent strut 34, to divert the post slightly away from the shoe pad laterally, for properly positioning the leg socket 69 for comfortable accommodation of the users leg. The several openings indicated at 74 in the material of shoe pad 30, may be provided if desired, to receive screws, bolts, or other fasteners whereby the shoe of the user may be permanently fixed to the shoe pad. Of course, it may not always be considered desirable to so iix the shoe to the pad, and in such cases the shoe may be more temporarily applied as by means of straps or clips, for example, asshoes are customarily mounted upon skis or skates.

In conclusion, it may be noted that the device of the invention is capable of fabrication with the generous use of a light-weight metal such as aluminum, with obvious advantage. As shown in Fig. 2, a lift or pad 75 of rubber or similar flexible soft material may be applied to the botom of the footmember 31, to cushion the step and reduce noise in the use of the device. Such a pad or lift will be found advantageous also when the device is used in walking upon finished vor polished surfaces, to avoid slipping and any tendency to mar or scratch the surface.

It is to be understood that various modifications and changes in structural details and materials may be resorted to in fabricating the device, within the scope of the appended claims, without departing from the spirit of the invention.

What I claim is:

1. In a device of the class described, the combination of a horizontal elongated foot member, a horizontal elongate shoe pad, and front and rear substantially vertical struts having upper and lower ends, means hingedly mounting the upper ends of both struts to the shoe pad and means hingedly mounting the lower ends of both struts to the foot member, the hinge means being arranged transversely of the shoe pad and the foot member, whereby the struts may be inclined forwardly and rearwardly from the vertical in the direction of the major axis of the foot member, and yielding means operative upon at least one of the struts opposing inclination of the struts from the substantially vertical position.

2. In a device of the class described, the combination of a horizontal elongate foot member, a horizontal elongate shoe pad, and front and rear substantially vertical struts having upper and lower ends, means hingedly mounting the upper ends of both struts to the shoe pad and means hingedly mounting the lower ends of both struts to the foot member, the hinge means being arranged transversely of the shoe pad and the foot member, whereby the struts may be inclined forwardly and rearwardly from the vertical in the direction of the major axis of the foot member, and yielding means operative upon at least one of the struts opposing inclination of the struts from the substantially vertical position, said yielding means being adjustable as to its force of opposition.

3. In a device of the class described, the combination of a horizontal elongate foot member, a horizontal elongate shoe pad, and front and rear substantially vertical struts having upper and lower ends, transverse hinge means on the shoe pad mounting the upper ends of the struts upon said pad, other transverse hinge means on the foot member mounting the lower ends of the struts on said foot member, with the struts in a substantially vertical normal position, yielding means resisting hinging movement of the struts from the vertical to inclined positions at opposite sides of the vertical, and means associated with said yielding means, to establish a differential between the resistive force opposing movement of the struts in one direction from the vertical, as distinguished from the resistive force opposing movement of the struts in the opposite direction from the vertical.

4. A device in accordance with claim 3, in which the yielding means comprises a single compression spring, and means for altering the effective force of said spring.

5. In a device of the class described, the combination of a horizontal foot member, a horizontal shoe pad, and front and rear substantially vertical struts having upper and lower ends, transverse hinge means on the shoe pad mounting the upper ends of the struts upon said pad for rocking movement of the struts to forward and rearward inclinations, other transverse hinge means on the foot member mounting the lower ends of the struts on said foot member for rocking movement of the struts to forward and rearward inclinations, an abutment on the front strut, and a second abutment on the rear strut, said abutments being near the shoe pad and arranged transversely thereof, an equalizing lever in the form of a bell crank having a horizontal arm, a depending arm, and an intermediate portion, means pivoting the intermediate portion of the equalizing lever upon the shoe pad, with the depending arm thereof impinging against the abutment on the rear strut, and the horizontal arm thereof extending toward the front strut, a. second equalizing lever in the form of a bell, crank yhaving a Vhorizontal arm, a depending arm, and an intermediate portion, means pivoting the intermediate yportion of the second equalizing lever upon theshoe pad, with the depending arm thereof irnpinging against the abutment on the front strut, and the horizontal arm thereof extending toward the rear strut in substantial parallelism with the horizontal arm of the rst equalizing lever, yielding means operative constantly to urge the horizontal arms of the equalizing levers upwardly toward the shoe p-ad, and a stabilizing post movable with one of the struts and including an upper end for attachment to the human body.

6. A device in accordance with claim 5, in which the yielding means acts upon the horizontal arms of the equalizing levers at different distances from the pivotal mountings thereof.

7. A device in accordance with claim 5, in which the combination includes means to 'vary the force with which the horizontal arms of the equalizing levers are urged toward the shoe pad by the yielding means.

8. In a device of the class described, the combination of a horizontal foot member, a horizontal shoe pad, and front and rear substantially vertical struts having upper and lower ends, transverse hinge means on the shoe pad mounting the upper ends of the struts upon said pad for rocking movement of the struts to forward and rearward inclinations, other transverse hinge means on the foot member mounting the lower ends of the struts on said foot member for rocking movement of the struts to forward and rearward inclinations, an abutment on the front strut, and a second abutment on the rear strut, an equalizing lever in the form of a bell crank having a horizontal arm, a depending arm, and an intermediate portion, means pivoting the intermediate portion of the equalizing lever upon the shoe pad, with the depending arm thereof impinging against the abutment on the rear strut, and the horizontal arm thereof extending toward the front strut, a second equalizing lever in the form of a bell crank having a horizontal arm, a depending arm, and an intermediate portion, means pivoting the intermediate portion of the second equalizing lever upon the shoe pad, with the depending arm thereof impinging against the abutment on the front strut, and the horizontal arm thereof extending toward the rear strut in substantial parallelism with the horizontal arm of the first equalizing lever, a threaded rod depending from the shoe pad intermediate the equalizing lever pivots, and passing alongside the horizontal arms of said levers, a compression spring encircling said rod and having one end abutting the horizontal arms of both equalizing levers, and a nut on the threaded portion of the rod abutting the opposite end of the spring, for advancing and retracting the spring relative to said horizontal lever arms.

9. A device in accordance with claim 8, in which the threaded rod depending from the shoe pad, is more distant from the pivot means of the first mentioned equalizing iever than from the pivot means of the second equalizing ever.

10. A device in accordance with claim 8, in which the threaded rod depending from the shoe pad, is located at unequal distances from the pivot means of the first and second equalizing levers, and the combination includespan upright post movable with the rear strut, said post having an upper end projecting above the shoe pad and including means for attachment of the post to a part of the human body.

11. In a device of the class described, the combination of an elongate foot member, an elongate shoe pad, and front and rear struts having upper and lower ends, means hingedly mounting the upper ends of both struts to the shoe pad and means hingedly mounting the lower ends of both struts to the foot member, the hinge means 7 being arranged transversely of the shoe pad and the foot extending above the shoe pad and including means for member, whereby the struts may be inclined forwardly attachment to a part of the human body. and rearwardly relative to the foot member in the direction of its major axis, to and from a right parallelo- References Cmd m the me of this patent gramic form constituted of the hinged shoe pad, the foot 5 UNITED STATES PATENTS member, and the struts, yielding means operative upon the struts when inclined as stated, tending to restore the 1613535 Root Jan' 4 1927 right parallelogramic relationship of the parts, and an FOREIGN PATENTS upstanding post movable with one of the struts, said post 476,134 Germany Apr. 12, 1928