US3737009A - Wheel chair lift - Google Patents

Abstract

A lift is described which provides a convenient and safe means for lifting objects and/or personnel for a limited height. In particular, the lift provides a means whereby a person in a wheel chair may be raised a given distance, such as the height necessary to enter a trailer. In addition to the basic lifting mechanisms, the lift provides a safety feature whereby a lip, connected to the lifting platform and actuated by the upward movement of the platform, pivots upwardly and prevents an inadvertent roll-off of the wheel chair. The structure about the platform includes sheet material about three sides and a hinged flap across the fourth side. As the platform is raised, the hinged flap, normally urged into a horizontal position by a spring, is pivotally raised underneath the rising platform whereby the fourth side is sealed off to prevent children or pets from crawling under the raised platform with subsequent injury should the platform lower upon them. On descent, the frontal lip pivots forwardly and downwardly whereby, when the platform contacts the ground, the lip will provide a short ramp to the ground. Simultaneously, the flap, raised into an upright position on ascent, pivots to a horizontal position under force of the spring.

Description

Stoddard 51 June 5, 1973 i 1 WHEEL CHAIR LIFT Joseph L. Stoddard, 9450 Nogales Highway, Tucson, Ariz. 85706 [22] Filed: Nov. 1, 1971 [21] Appl. No.: 194,675

[76] Inventor:

[52] U.S. Cl. ..187/17, 187/1, 187/51,

187/8.52, 187/94, 187/98 [51] Int. Cl. ..B66b 11/04 [58] Field ofSearch ..187/10,12,20,51,

[56] References Cited UNITED STATES PATENTS Primary ExaminerHarvey C. Hornsby Attorney-William C. Cahill, Samuel .1. Sutton, Jr. and James H. Phillips I57] ABSTRACT A lift is described which provides a convenient and safe means for lifting objects and/or personnel for a limited height. in particular, the lift provides a means whereby a person in a wheel chair may be raised a given distance, such as the height necessary to enter a trailer. In addition to the basic lifting mechanisms, the lift provides a safety feature whereby a lip, connected to the lifting platform and actuated by the upward movement of the platform, pivots upwardly and prevents an inadvertent roll-off of the wheel chair. The structure about the platform includes sheet material about three sides and a hinged flap across the fourth side. As the platform is raised, the hinged flap, normally urged into a horizontal position by a spring, is pivotally raised underneath the rising platform whereby the fourth side is sealed off to prevent children or pets from crawling under the raised platform with subsequent injury should the platform lower upon them. On descent, the frontal lip pivots forwardly and downwardly whereby, when the platform contacts the ground, the lip will provide a short ramp to the ground. Simultaneously, the flap, raised into an upright position on ascent, pivots to a horizontal position under force of the spring.

7 Claims, 4 Drawing Figures Patented June 5, 19-73 3 Sheets-Sheet 1 INVENTOR,

Joseph L. Stoddard MBm M/ ATTYS.

Patented June 5, 1973 3 Sheets-Sheet 2 Fig 2 INVENTOR. Joseph L. Stoddard Patented June 5, 1973 3 Shuets-Sheet 5 INVENTOR.

Joseph L. Stoddard Mi wwzw Arrrs WHEEL CHAIR LIFT This invention relates to that class of devices useful for raising loads for a limited distance.

Recently developing sociological and economical changes have made trailers and trailer courts extremely popular among the elderly, particularly those who lived on limited means, that is, on pensions or annuities. Many of these persons are physically handicapped because of senescence or injury and some may in fact be incapable ofwalking for any extended distance. For this class of persons, who are relegated to a wheel chair for mobility and who are incapable of ascending steps without aid, there is a serious problem in mounting the entrance steps to their trailer. The use of inclined ramps leading up the the trailer have been attempted; however, these suffer from two very serious disadvantages. First, the ramp requires an extended amount of ground surface area in order to maintain a gradual slope. This is an impossibility in a crowded trailer park. The second problem arises in that many of this class of persons are not physically powerful enough to propel themselves up even a gradual ramp. Thus, their mobility is dependent on the use of an electric or otherwise powered wheel chair. These wheel chairs are expensive and beyond the means of many persons within this class.

A solution in the past has been that of employing one of the commercially available lifts. This solution was unsatisfactory in that many of these lifts were either very expensive and beyond the means of the aforementioned class of persons, or else did not provide sufficient safety features to permit the user to employ the lift without fear of possible injury.

It is therefore a primary object of the present invention to provide a lift fora wheeled vehicle which incorporates interlocking safety features whereby the occupants may employ the lift without fear of personal injury.

Another object of the present invention is to provide a lift for a wheeled vehicle which does not present a safety hazard to crawling children or pets.

Another object of the present invention is to provide a raised lip to prevent wheeled loads from rolling off the raised platform.

Still another object of the present invention is to provide an interlocked pivotal side co-operating with three fixed sides to establish a surrounding barrier beneath the raised platform.

These and other objects of the present invention will become apparent to those skilled in the art as the description thereof proceeds.

In describing the invention with more specificity, reference will be made to the following drawings, in

which:

FIG. 1 illustrates the basic structure taught in accordance with the teachings of the present invention.

FIG. 2 illustrates a cross section of the basic structure taken at line 2-2 of FIG. 1.

FIG. 3 illustrates the hinged flap forming the fourth side of the barrier surrounding the platform.

FIG. 4 illustrates a cross section of the basic structure taken atline 44 of FIG. 2.

Referring to FIG. 1, there is shown a lift assembly built according to the invention. The framework of the lift assembly includes fourupright supports 1, 2, 3, and 4, which are attached to a flatrectangular base 73. The

front upright supports 1, 2 are connected byhorizontal bars 5 and 6 to the rear extended upright supports 3 and 4, respectively. Supports 3 and 4 are braced by diagonal members 7 and 8 extending from points in proximity to the junction of support 1 andhorizontal bar 5 and support 2 and horizontal bar 6 to the upper portion of supports 3 and 4, respectively. In this fashion, theuprights 1, 2, 3, and 4, including their respective connecting members, form three sides of the lift framework. Extending upwardly from thebase 73 and along each of these three sides, defined byuprights 1 and 3, 3 and 4, and 4 and 2, there may bebarriers 9, 10, 11, respectively, of sheet-like material or screening. The height above the base of these barriers should be at least equal to the height of the raised position of theplatform 14. If desired, thebarriers 9, 10, and 11 may be designed to serve both as an additional support foruprights 1, 2, 3, and 4 and as a shroud about theplatform 14. Additional bracing, such astriangles 12 and 13, may be welded touprights 1 and 2 and thebase 73, to add rigidity to the structure.

The vertically moving platform assembly includes aplatform 14 and twovertical sides 15 and 16 extending upwardly from opposite sides of theplatform 14.Triangular braces 17 and 18 may be welded to theplatform 14 to secure the respective sides and provide additional rigidity. Channel members 19 and 20 are welded to thesides 15 and 16 respectively to co-operate with uprights 3 and 4, respectively, and act as guides when raising or lowering theplatform 14. The remaining two sides of theplatform 14 do not have any permanent barriers in order that a wheeled vehicle may be rolled onto the loweredplatform 14 from the front and off the rear ofplatform 14 when theplatform 14 is in the raised position.

Apivotable lip 21 is attached to and extends across the front portion ofth platform 14. A cord orcable 22 is attached to the front corner of thelip 21 and extends therefrom through apulley 74 attached to an upper portion ofbarrier 9 and then attaches to the upper portion of theside 15. In operation, thelip 21 functions as follows. When theplatform 14 is in the lowered position, thelip 21 acts as a ramp to permit an easy entry for a wheeled vehicle onto theplatform 14. As theplatform 14 begins to rise, the effective cord length between thelip 21 and the upper portion ofside 15 tends to be shortened due to the immobility of thepulley 74 through which thecord 22 must pass. Thus, the front of thelip 21 is forced to pivot upwardly towardplatform 14. Thereby, thelip 21 pivots upwardly beyond horizontal to provide an upward incline for a vehicle carried on theplatform 14; thus, the vehicle is inhibited from rolling off theplatform 14. If desired, asecond cord 23 may be used at the other side of the platform, operating in the previously described manner.

Each of the supports 3 and 4 includesshelf 24, 25 mounted in proximity to the top portion of the respective uprights. Each of theseshelves 24, 25 supports ajournalled sprocket 26, 27 respectively. The lower part of supports 3 and 4 include journalling means 75, 76 co-operating with anaxle 34 extending beyond the side of either one of the supports. Attached to either end ofaxle 34 aresprockets 28, 29. A pair ofchains 32, 33, which may be in the nature of bicycle chains, extend aboutsprockets 26, 28 and 27, 29 respectively. Anextension 30 and 31 is attached to each of the platform sides 15 and 16, and clamped, or otherwise secured to each of thechains 32, 33, such that the platform may not be raised nor lowered without causingsprockets 28, 29 and ultimatelyaxle 34 to rotate. Thus, any rotation ofaxle 34 will cause theplatform 14 to ascend or descend, depending on the direction of rotation. Asprocket 35 is rigidly attached toaxle 34 in proximity tosprocket 28. Asupport structure 37 attached to the side of the lift framework supportsajournalled axle 38.Pulley 39 andsprocket 40, operating as a rotating unit, are mounted onaxle 38.Chain 36 connectssprocket 40 to sprocket 35 whereby any rotation ofpulley 39 will necessarily cause some rotation ofaxle 34. Anelectric motor 24 having apulley 42 attached to the armature thereof drivespulley 39 through abelt 41 In operation, rotation of the armature ofmotor 24 necessarily rotatespulley 39 andsprocket 40.Sprocket 35, through movement ofchain 36, causesaxle 34 to rotate. Assprockets 28 and 29 are firmly attached toaxle 34,sprockets 26 and 29 will be rotatably driven throughchains 32 and 33. Any movement of thechains 32, 33 will cause theplatform 14 to move upwardly or downwardly due to the interconnection throughattachments 30 and 31.

A pair ofcounterweights 43, 44 attached bycords 45, 46 to theplatform 14 throughpulleys 47, 48 are designed to place theplatform 14 in a condition of near equilibrium. That is, without the application of an outside force, theplatform 14 will neither ascend nor descend.

Aswitch 49, which may be conveniently placed on the upper edge of one side of the raised sides ofplatform 14, such as side as shown, controls the power to theelectric motor 24. Theswitch 49 is connected so that as it is placed in the ON position, themotor 24 will be actuated, causing theplatform 14 to rise. Asecond switch 50, which may be placed upon one of the uprights, such as upright 4 as shown, operates to shut offmotor 24. Theswitch 50 may either be manually operated or it may be automatically operated througharm 51 extending aboveth platform side 16. Thus, as the lift is set in motion by actuation ofswitch 49,platform 14 will continue to rise untilupright arm 51 actuates switch 50 to turn themotor 24 off.

As previously mentioned, theplatform 14 will neither ascend nor descend due to its own weight because of the counterweight system. Th inclusion of passengers or goods will, however, upset this balance. The gearing arrangement used by the combination of pulleys and sprockets is designed such that in order for there to be movement of theplatform 14, the armature ofmotor 24 must turn at a relatively high rate. This requirement, plus the inherent frictional resistance present in the lift insures that after the power to themotor 24 is turned off, theplatform 14 descends relatively slowly. To lock theplatform 14 at any given position, a brake may be utilized. This brake may be desired whenmotor 24 is shut off and theplatform 14 is in its raised position. Thereby, theplatform 14 will not suddenly 0r unexpectedly begin to descend during the loading or unloading operation. The design of the brake may be quite elaborate if desired or may be a simple go/no-go type of system. A simple but satisfactory brake system will be described. Abrake shaft 52 may be journalled at 53 on diagonal support 7 and at 54 onhorizontal support 5. One end of theshaft 52 includes abrake shoe arrangement 57, which under pressure ofsprings 55, 56, exerts a force upon the edges ofpulley 39, thus retarding or inhibiting rotation of the pulley. The other end of theshaft 52 may include a horizontally projectingextension 59 riding upon a cam orinclined plane 77 such that if theshaft 52 rotated. withinjournals 53, 54, thehorizontal extension 59 rides up theinclined plane 77 and releases thebrake shoe 57 from thepulley 39. Ahandle 58 may be connected toextension 59 for ease in operating the brake. The effectiveness of the brake may be increased by aligning theshaft 52 off center ofpulley 39 and counter to the expected direction of rotation. Thereby, any rotation ofpulley 39 resulting from the load placed onplatform 14 will tend to force thebrake shoe 57 upwardly and increase the force of thebrake shoe 57 on the edge ofpulley 39.

In operation, an occupant of the lift would utilize the brake in the following manner. Upon reaching the higher elevation after themotor 24 is shut off through actuation ofswitch 50 byarm 51 andplatform 14, the lift will stop. At this time, the occupant would be within easy reach ofhandle 58, and could then swing or rotate th handle 58 such thatextension 59 interacted with theinclined plane 77 to set thebrake shoe 57 on the edge ofpulley 39. The platform '14 would then be immobile for all practical purposes and the occupant could leave theplatform 14 without fear of it suddenly beginning to descend due to his weight. On re-entering the lift at the raised position, the occupant would begin his descent by simply rotatinghandle 58 so as to release thebrake shoe 57 from contact with the edge ofpulley 39 and calmly await descent of theplatform 14.

As previously mentioned, thesheet material 9, l0, and 11 collectively act to create a barrier about the sides of theplatform 14. A primary purpose of this barrier is to prevent pets, small children, or other things from crawling under or being placed beneath theplatform 14 while theplatform 14 is. in the raised position. Subsequent descent by theplatform 14 could conceivably cause irreparable damage to these children, pets, or other things. In order to provide a four-sided barrier, a fourth side may be used which is actuated by movement of theplatform 14 itself.

Referring to FIG. 3, aflap 60, pivotally mounted at 68 coincident with the front edge of the fourth side ofbase 73 is spring-biased byspring 61 suitably attached atpoint 62 to either the base 73 or a portion of the base framework such that theflap 60 in its normal position lies horizontally and will not impinge upon or impede the movement of theplatform 14. When theplatform 14 is raised, acord 69 attached to theflap 60 and a fixedpoint 67 on the raisedside 15 of theplatform 14causes flap 60 to pivot into an upright position. The point ofattachment 70 between thecord 69 and theflap 60 must, of course, be predetermined from the known height to which theplatform 14 rises in order that theflap 60 obtain a vertical position at the apex of theplatform 14 ascent. Thus, while theplatform 14 is in the raised position, thebase 73 of the lift framework is surrounded on all four sides by a barrier whereby foreign objects cannot be inadvertently or by design be placed beneath theplatform 14. On descent, theflap 60 pivotally swings out of the way under force ofspring 61 so that it will not interfere with the egress of the occupant from theplatform 14.

As a further safety precaution, an enclosure 71, shown in cutaway view in FIG. 1, may be placed about the counterweight, motor, pulleys, and sprockets. Similarly, asecond enclosure 72 may house the counterweight and sprockets on the opposite side of the lift framework.

I claim:

1. A vertically moving platform assembly within a supporting and guiding framework, including a base having a plurality of sides, a barrier extending upwardly from less than all the sides thus providing at least one open side, and power means for raising the platform, comprising:

a hinged lip pivoted to one edge of the platform for providing a ramp for ease of ingress and egress when the latter is in its lowered position,

flexible means connected between said lip and said platform for rotating said lip upwardly in response to an upward movement of the platform,

a hinged flap pivoted to said open side of the base of the framework about a horizontal pivot point for movement between a horizontal position beneath said platform when said platform is a lowered position and a raised vertical position upon elevation of said platform, said flap being at all times disposed beneath a plane defined by the platform, and

flexible means connected between said flap and said platform for pivoting said flat upwardly about said horizontal pivot point in response to an upward movement of the platform to form a continuous barrier about the raised platform, whereby a load elevated by the platform will be retained on said platform by said lip and the barrier will prevent ingress of foreign objects beneath the raised platform.

2. A vertically moving platform assembly as claimed in claim 1, comprising:

a counterweight system attached to the platform and co-operating with the framework, whereby vertical movement of an unloaded platform must be initiated by an outside force.

3. A vertically moving platform assembly as claimed in claim 1, wherein said pivoting means comprises:

a spring connected between said flap and the framework for urging said flap to a horizontal position, and

a cord connected between said flap and the platform, whereby movement of the platform is translated through said cord into a pivotal movement of said flap counter to the spring force.

4. A vertically moving platform assembly as claimed in claim 1, wherein said rotating means comprises:

a cord having one end attached to said lip and the other end attached to the platform assembly, and

a pulley attached to the framework for engaging said cord, whereby movement of the platform relative to the framework will shorten the effective cord length causing said lip to rotate upwardly.

5. The power means as claimed in claim 1, comprising:

an electric motor attached to the framework,

means for converting the rotary output of said electric motor into a vertically moving element, and

means for connecting said element to the platform, whereby the rotary output of said electric motor is translated into a vertical movement of the platform.

6. The power means as claimed inclaim 5, including:

a manually operated switch for energizing said electric motor, and

an automatically operated switch for de-energizing said electric motor when the platform has reached its apex.

7. The power means as claimed in claim 6, wherein said manual switch is attached to the platform, and

said automatic switch is actuated in response to a predetermined relative movement between the framework and the platform.

Claims (7)

1. A vertically moving platform assembly within a supporting and guiding framework, including a base hAving a plurality of sides, a barrier extending upwardly from less than all the sides thus providing at least one open side, and power means for raising the platform, comprising: a hinged lip pivoted to one edge of the platform for providing a ramp for ease of ingress and egress when the latter is in its lowered position, flexible means connected between said lip and said platform for rotating said lip upwardly in response to an upward movement of the platform, a hinged flap pivoted to said open side of the base of the framework about a horizontal pivot point for movement between a horizontal position beneath said platform when said platform is a lowered position and a raised vertical position upon elevation of said platform, said flap being at all times disposed beneath a plane defined by the platform, and flexible means connected between said flap and said platform for pivoting said flat upwardly about said horizontal pivot point in response to an upward movement of the platform to form a continuous barrier about the raised platform, whereby a load elevated by the platform will be retained on said platform by said lip and the barrier will prevent ingress of foreign objects beneath the raised platform.

2. A vertically moving platform assembly as claimed in claim 1, comprising: a counterweight system attached to the platform and co-operating with the framework, whereby vertical movement of an unloaded platform must be initiated by an outside force.

3. A vertically moving platform assembly as claimed in claim 1, wherein said pivoting means comprises: a spring connected between said flap and the framework for urging said flap to a horizontal position, and a cord connected between said flap and the platform, whereby movement of the platform is translated through said cord into a pivotal movement of said flap counter to the spring force.

4. A vertically moving platform assembly as claimed in claim 1, wherein said rotating means comprises: a cord having one end attached to said lip and the other end attached to the platform assembly, and a pulley attached to the framework for engaging said cord, whereby movement of the platform relative to the framework will shorten the effective cord length causing said lip to rotate upwardly.

5. The power means as claimed in claim 1, comprising: an electric motor attached to the framework, means for converting the rotary output of said electric motor into a vertically moving element, and means for connecting said element to the platform, whereby the rotary output of said electric motor is translated into a vertical movement of the platform.

6. The power means as claimed in claim 5, including: a manually operated switch for energizing said electric motor, and an automatically operated switch for de-energizing said electric motor when the platform has reached its apex.

7. The power means as claimed in claim 6, wherein said manual switch is attached to the platform, and said automatic switch is actuated in response to a predetermined relative movement between the framework and the platform.

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