US3589537A

US3589537A - Platform elevator

Info

Publication number: US3589537A
Application number: US796417A
Authority: US
Inventors: John F Petersen
Original assignee: Individual
Current assignee: Individual
Priority date: 1969-02-04
Filing date: 1969-02-04
Publication date: 1971-06-29
Anticipated expiration: 1988-06-29

Abstract

A platform is supported at its outer end on an outer arm connected pivotally to an inner arm which is mounted pivotally on a vehicle-supported frame for vertical movement relative to the latter by a fluid pressure cylinder interengaging the frame and inner arm. The inner end of the platform is supported by one arm of a bell crank lever pivoted intermediate its ends on the inner arm. The other arm of the bell crank lever is connected pivotally to the frame, whereby vertical movement of the inner and outer arms moves the platform vertically while maintaining its level. A fluid pressure cylinder interengages the inner and outer arms to pivot the outer arm relative to the inner arm to fold the platform against the vehicle when not in use.

Description

United States Patent- [72] inventor John F. Petersen 5626 N. E. 42nd Avenue, Apt. D, Portland, Greg/97218 [21] Appl. No. 796,417

[22] Filed Feb. 4, 1969 [45] Patented June 29, 1971 [54] PLATFORM ELEVATOR 9 Claims, 8 Drawing Figs.

(52] 11.8. CI 214/75, 214/77 [51] Int. Cl 860p H44 [50] Field of Search 214/75 T,

[56] Relerenoes Cited UNITED STATES PATENTS 2,414,684 H1 947 Wohlforth 2,626,067 1] 1953 Berford et aL. 2,706,102 4/1955 Cresci 2,768,758 10/1956 French.... 2,8 89,059 6/1959 Selaer 214/75 (T) 214/77 (P) 254/124X 214/77 (P) 214/77 (P) 2,979,214 4/1961 Selzer 2l4/77(P) 3,362,547 1/1968 Kovarik 2l4/77(P) FOREIGN PATENTS 1,229,575 3/1960 France 214 771 Primary Examiner-Gerald M. Forlenza Assistant Examiner-Robert J. Spar Attorney-Oliver D. Olson ABSTRACT: A platform is supported at its outer end on an outer arm connected pivotally to an inner arm which is mounted pivotally on a vehicle-supported frame for vertical movement relative to the latter by a fluid pressure cylinder interengaging the frame and inner arm. The inner end of the platform is supported by one arm of a bell crank lever pivoted intermediate its ends on the inner arm. The other arm of the bell crank lever is connected pivotally to the frame, whereby vertical movement of the inner and outer arms moves the platform vertically while maintaining its level. A fluid pressure cylinder interengages the inner and outer arms to pivot the outer arm relative to the inner arm to fold the platform against the vehicle when not in use.

PATENTED JUN29 I97! SHEET 2 BF 2 JOHN F. PETERSEN Q VEN AGENT PLATFORM ELEVATOR BACKGROUND OF THE INVENTION This invention relates to elevators, and more particularly to a simplified platform elevator adapted for convenient attachment to vehicles.

Platform elevators have been provided heretofore for use at the rear end of trucks for loading and unloading cargo. However, such elevators are characterized by several disadvantages, principally their massive, complex and costly construction which limit their use to large trucks and which require substantial modification of such trucks.

Another important application for platform elevators is as an adjustable step for campers, mobile homes and other dwellings occupied by persons confined to wheelchairs or otherwise crippled to an extent which prevents their use of a fixed step. A platform elevator capable of such use has not been provided theretofore.

SUMMARY OF THE INVENTION In its basic concept the platform elevator of the present invention utilizes a pair of relatively movable lever members mounted on a frame in such manner as to support a platform for vertical movement while maintaining it level. The simplified assembly is readily attached to a vehicle without modification to provide a variety of functions.

It is by virtue of the foregoing basic concept that the principal objective of the present invention is achieved, namely to overcome the disadvantages of prior platform elevators and to provide additional functions not afforded by prior platform elevators, as enumerated hereinbefore.

The foregoing and other objects and advantages of the present invention will appear from the following detailed description, taken in connection with the accompanying drawings of the preferred embodiments. BRIEF DESCRIP- TION OF THE DRAWINGS FIG. 1 is a fragmentary view in side elevation, partly in section, of a platform elevator embodying the features of the present invention, the same being illustrated mounted on the underside of a mobile home for use as an adjustable step, the platform being shown in its lowered position.

FIG. 2 is a fragmentary side elevation similar to FIG. I but showing the platform in an intermediate position of elevation.

FIG. 3 is a fragmentary side elevation, similar to FIGS. I and 2 but showing the platform in its fully raised position.

FIG. 4 is a fragmentary, foreshortened view in side elevation showing the platform in folded condition adjacent the outer side of the mobile home.

FIG. 5 is a fragmentary sectional view taken on the line 5-5 in FIG. 11.

FIG. 6 is a fragmentary sectional view taken on the line 6-6 in FIG. 5.

FIG. 7 is a fragmentary sectional view taken on the line 7-7 in FIG. 5.

FIG. 8 is a fragmentary view in side elevation of an alternative connector for the leveling lever.

DESCRIPTION OF THE PREFERRED EMBODIMENTS For purposes merely of description the platform elevator of the present invention is illustrated in the drawings in cooperative association with a mobile home which includes a floor I0 supported upon spaced beams 12 which, in turn, are supported resiliently on wheels (not shown). In one of the confining walls 14 of the mobile home is a door 16 which removably closes an opening through which persons may enter and leave. A peripheral skirt I8 depends from the floor.

Since the floor of the mobile home is elevated a substantial distance above the ground, the platform elevator of the present invention finds effective utility both as an intermediate step (FIG. 2) and as an elevator for raising and lowering a disabled person to and from the mobile home.

The operating components of the platform elevator of the present invention are mounted upon a pair of spaced frames 20 which may be attached to the underside of the mobile home with speed and facility and without modifying the latter. In the embodiment illustrated each frame is attached to the spaced beams 12 underlying the floor by means of depending brackets 22. The brackets are secured at their lower ends to the frame 20 and may be attached at their upper ends to the beams 12 of the mobile home by such means as bolts. These brackets are dimensioned to space the frames sufficiently below the floor of the mobile home to permit operation of the moving parts of the elevator unobstructed by the floor, beams 12 and the depending peripheral skirt I8.

An elongated arm member is supported below each frame 20 for vertical movement relative thereto. In the embodiment illustrated each arm member includes an inner section 24 and an outer section 26 connected together pivotally by means of the pivot shaft 28. This shaft extends between both arm members, and the outer sections 26 are secured to the shaft for rotation therewith. The adjacent ends of the arm sections may be provided with walls 24 and 26', respectively (FIG. 7) which normally abut each other. The inner end of the inner section is connected pivotally to the frame by means of the pivot pin 30, and the outer section is disposed outward of the adjacent side of the mobile home.

Power means is provided for moving both arm members simultaneously relative to their associated frames. In the embodiment illustrated this power means includes a fluid pressure cylinder unit of the pneumatic or, preferably, hydraulic type. One end of the cylinder 32 of the unit is mounted pivotally, by means of the pivot pin 34, on a bracket 36 extending from one of the frame 20. The piston rod 38 projecting from the opposite end of the cylinder is connected pivotally, by means of the pivot pin 40, to one arm 42 of a bell crank lever. This lever is secured intermediate its ends to the elongated pivot shaft 44 journaled at its opposite ends in bearings 46 secured to the frames. The outer end of the other arm 48 of the bell crank lever supports a shaft 50 which mounts a roller 52. The roller underlies and supports the inner section 24 of the associated arm member. A lever, similar to lever 48, is secured to the shaft 44 adjacent the other frame 20 to support the inner section 24 of the associated arrn member by means of a similar shaft 50 and roller 52. Thus, application of fluid pressure selectively to the opposite ends of the cylinder 32 effects vertical movement of the arm members pivotally about the pivot pins 30.

The outer ends of the outer sections 26 of the arm members support the outer end of a platform 54. In the embodiment illustrated a pin 56 pivotally interconnects the platform and each outer section to prevent relative displacement.

Means is provided for supporting the inner end of the platform adjustably for maintaining the platform level during its vertical movement with the arm members. In the embodiment illustrated this means comprises a bell crank lever associated with each arm member. Each lever is mounted pivotally intermediate its ends on the inner section 24 of the associated arm member. This pivot mounting is provided conveniently by the pivot shaft 28 which interconnects the inner and outer sections. One arm 58 of the bell crank lever projects inwardly and is connected pivotally to the associated frame 20 in such manner that vertical movement of the inner section of the arm member effects pivotal movement of the bell crank lever. In the embodiment illustrated in FIGS. 14 of the drawings, this pivotal connection is provided by the link members 60 which is connected at one end to the bell crank lever arm 58 by means of the pivot pin 62 and at the opposite end to the frame bracket 20' by means of the pivot pin 64.

In FIG. 8 of the drawings this pivotal connection is provided by means of the guide plate 66 secured to the frame 20 and provided with the arcuate slot 68. A pin 70 at the terminal end of the bell crank lever arm 58 slidably engages the slot, whereby to guide the bell crank lever through its range of pivotal movement, in manner similar to the function of the link member 60.

The other arm 72 of each bell crank lever projects outward, and its tenninal end supports the inner end of the platform 54. Although the inner end of the platform may rest freely on the bell crank lever arms, it is preferred that it be connected thereto in order to prevent upsetting of the platform inadvertently by the application of sufficient downward force outward of the outer ends of the outer sections of the arm members. Accordingly, in the embodiment illustrated, a pin-mounted roller 74 (FIGS. 5 and 6) projects from the terminal end of each bell crank lever arm 72 and slidably engages a contoured slot 76 in the guide plate 78 secured to the inner side of the platform. The contour of the slot is chosen to accommodate the relative movement of the platform and lever arm through the positions illustrated in FlGS. l4.

It is to be remembered that the adjacent ends of the inner and outer sections of each arm member have walls 24' and 26' which remain in abutment throughout the vertical movement of the platform between the lowered and raised positions illustrated in FIGS. l-3. Accordingly, if it is not required that the platform be capable of folding to the position illustrated in FIG. 4, each arm member may be made as a single, rigid, integral unit, rather than as the pivoted sections illustrated.

However, the provision of the pivotally interconnected inner and outer sections of each arm member affords folding of the platform vertically to a position adjacent the outer side of the mobile home, as illustrated in FIG. 4. This folding operation is accomplished, after the platform has been elevated to the uppermost position illustrated in FIG. 3, by pivoting the outer sections 26 of the arm members counterclockwise about the pivot shafts 28. The inner end of the platform thus moves downward toward the outer sections of the arm members, as permitted by the movement of the roller 74 at the outer end of the bell crank lever arm 72 outward along the slot 76 in the guide plate 78.

Although folding and unfolding of the platform to the respective positions illustrated in H65. 4 and 3 may be accomplished manually, means preferably is provided by which to effect these movements by mechanical power. In the embodiment illustrated this power means comprises a fluid pressure cylinder unit. One end of the cylinder 80 is connected pivotally to the inner section 24 of the associated arm member, by means of the pivot pin 82. The piston rod 84 projecting from the opposite end of the cylinder is connected pivotally, by means of the pivot pin 86, to the bracket 88 projecting inward from the inner end of the outer section 26 of the same ann member.

Thus, by application of fluid pressure selectively to the opposite ends of the cylinder 80, the outer sections 26 of the arm members are caused to be pivoted with the shaft 28, to effect folding and unfolding of the platform 54.

lt will be apparent that, with the provision of cylinder 80, the walls 24' and 26' advantageously may be omitted since the cylinder may function to secure the arm sections together in various positions of angular adjustment. This arrangement affords leveling of the platform even though the vehicle may be on an inclined surface.

The

cylinders

32 and 80 may be connected to a source of fluid pressure through various types of control valves, such as manually operated valves or electrical solenoid valves. In any case, it is desirable that the valve controls be located adjacent the door 16 for convenient operation.

ln the operation of the platform elevator described hereinbefore let it first be assumed that the platform 54 is in the folded position illustrated in FIG. 4 and that it is the desire of the occupant of the mobile home to leave the latter. Accordingly, the occupant operates a valve control to apply fluid pressure to the cylinder 80 to retract the associated piston rod 84. The outer section 26 of each arm member thus pivots clockwise with the pivot shaft 28 and the rollers 74 at the outer ends of the bell crank lever arms 72 glide inward along the contoured slots 76 in the guide plates 78, until the platform is disposed in a position illustrated in FIG. 3. The occupant then opens the door 16 and moves onto the platform. The platform is made sufi'iciently large to support a wheelchair, if

the occupant is so confined. The occupant then operates a valve control to apply fluid pressure to the cylinder 32 to effect retraction of its associated piston rod 38. The connected bell crank levers thus rotate clockwise with pivot shaft 44 from the position illustrated in FIG. 3 to the position illustrated in HO. 1, whereupon the platform is lowered to the ground. During this vertical movement the platform has been maintained level by virtue of the simultaneous clockwise rotation of the leveling bell crank levers with their pivot shaft 28.

Although the platform elevator described hereinbefore has been illustrated in association with the doorway of a mobile home, it will be apparent that it may be utilized in other environments and for other purposes. For example, it may be mounted at the rear of a truck for use as a combined tail gate (FIG. 4) and as a cargo elevator (FIGS. l3). It may also be mounted at the side of a truck having a side opening door, to serve as a cargo loader and unloader. Because of its construction it may be attached in these various ways to small trucks as well as large trucks, with speed and facility and without modification of the truck.

It will be apparent to those skilled in the art that various changes may be made in the number, size, shape and arrangement of parts described hereinbefore, without departing from the spirit of this invention.

Having now described my invention and the manner in which it may be used, I claim:

lclaim:

l. A platform elevator comprising a. a frame,

b. an elongated arm member including an inner section pivoted to the frame and an outer section pivoted to the inner section and projecting outward from the frame,

0. power means interengaging the frame and inner section of the arm member for moving the latter vertically relative to the frame,

d. lever means mounted pivotally intermediate its ends on the arm member,

e. connector means pivotally interengaging one end of the lever means and the frame for moving said end of the lever means arcuately relative to the frame and for permitting pivoting of the lever means by movement of the arm member relative to the frame, and

. a platform supported at its inner end on the other end of said lever means and at its outer end on the projecting end of the outer section of the arm member,

g. the outer section of the arm member being pivotable relative to the inner section to move the platform between an extended position projecting horizontally outward from the frame and a retracted position projecting vertically upward adjacent the frame.

. The platform elevator of claim 2 including pivot means interconnecting the inner end of the inner section ofthe arm member and the frame, and

b. bell crank lever means mounted pivotally intermediate its ends on the frame with one arm of the bell crank lever means engaging the inner section of the arm member and the other arm of the bell crank lever means engaging the power means.

3. The platform elevator of claim 1 including pivot means interconnecting the outer end of the platform and the outer end of the outer section of the arm member.

4. The platform elevator of claim 1 including pivot means interconnecting the inner end of the platform and the said other end of the lever means.

5. The platform elevator of claim 4 wherein the pivot means comprises a guide member on the platform, and projecting means on the said other end of the lever means engaging an elongated slot in said guide member.

6. The platform elevator of claim 1 wherein the connector means comprises a link member pivotally interconnected the lever means and frame.

7. The platform elevator of claim 1 wherein the connector means comprises a guide member on the frame having an ar- 9. The platform elevator of claim 1 including means on the frame adapted for attachment to a vehicle for mounting the frame on the underside of the vehicle with the outer section of the arm member disposed outward of the vehicle.

Claims

1. A platform elevator comprising a. a frame, b. an elongated arm member including an inner section pivoted to the frame and an outer section pivoted to the inner section and projecting outward from the frame, c. power means interengaging the frame and inner section of the arm member for moving the latter vertically relative to the frame, d. lever means mounted pivotally intermediate its ends on the arm member, e. connector means pivotally interengaging one end of the lever means and the frame for moving said end of the lever means arcuately relative to the frame and for permitting pivoting of the lever means by movement of the arm member relative to the frame, and f. a platform supported at its inner end on the other end of said lever meanS and at its outer end on the projecting end of the outer section of the arm member, g. the outer section of the arm member being pivotable relative to the inner section to move the platform between an extended position projecting horizontally outward from the frame and a retracted position projecting vertically upward adjacent the frame.

2. The platform elevator of claim 2 including a. pivot means interconnecting the inner end of the inner section of the arm member and the frame, and b. bell crank lever means mounted pivotally intermediate its ends on the frame with one arm of the bell crank lever means engaging the inner section of the arm member and the other arm of the bell crank lever means engaging the power means.

7. The platform elevator of claim 1 wherein the connector means comprises a guide member on the frame having an arcuate slot therein, and projecting means on the lever means engaging the slot.

8. The platform elevator of claim 1 including power means interengaging the inner and outer sections of the arm members for pivoting the outer section relative to the inner section between said extended and retracted positions.

9. The platform elevator of claim 1 including means on the frame adapted for attachment to a vehicle for mounting the frame on the underside of the vehicle with the outer section of the arm member disposed outward of the vehicle.