US3521861A

US3521861A - Vehicle lift

Info

Publication number: US3521861A
Application number: US680440A
Authority: US
Inventors: Frank D Freudenthal; Gilbert W Gaarder
Original assignee: Gray Manufacturing Co Inc
Current assignee: Gray Manufacturing Co Inc
Priority date: 1967-11-03
Filing date: 1967-11-03
Publication date: 1970-07-28
Anticipated expiration: 1987-07-28

Description

July 28, 1970 D. FREUDENTHAL ET AL 1,

VEHICLE LIFT 2 SheetS-Sheet 1 Filed Nov. 5. 1967 5 5 Wd B N NJl a R m fi o M I Q 7 1 u a A m F 0. 0 a w a Z V. I B 1/ l v I I l I I I .XMY A\\ y 1970 F. D. FREUDENTHAL. ET 3,521,361

VEHICLE LIFT Filed NOV. 5, 1967 2 Sheets-Sheet a ATT NEYIS United States Patent 3,521,861 VEHICLE LIFT Frank D. Freudenthal and Gilbert W. Gaarder, St.

Joseph, Mo., assignors to Gray Manufacturing Company, Inc, St. Joseph, Mo., a corporation of Missouri Filed Nov. 3, 1967, Ser. No. 680,440 Int. Cl. 1366f 3/24, 5/04 U.S. Cl. 254-93 8 Claims ABSTRACT OF THE DISCLOSURE A low profile fluid operated lift for vehicles having a wheeled frame, the frame supporting a generally declining force fluid powered actuator in the nature of a flexible bellows, there being generally increasing force mechanical linkage coupled with the actuator whereby, when fluid is introduced into the bellows under substantially constant pressure the lift will be raised at a substantially constant load capacity. The mechanical linkage includes a pivot arm and a lifting arm, there being a link coupling said arms which is under tension during raising of the lift whereby the initial lifting capacity of the lift is essentially the same as the terminal lifting capacity, such lifting capacity being substantially constant during raising of the lift. A safety lock assembly is provided to retain the lift in a raised position for the safety of a user working under the lifted vehicle, there being means for releasing the safety lock whereby the lift may be brought to a fully lowered position.

It is the primary object of this invention to provide a vehicle lift which includes a frame, the frame supporting thereupon an actuator in the form of a fluid powered bellows, the bellows being coupled with mechanical linkage whereby, when the bellows, which, at a constant supply pressure, is a declining force power source, is actuated, the coupling thereof with the mechanical linkage, which is an increasing force power source, will result in the exertion of a substantially constant lifting force upon the vehicle.

It is another important object of this invention to provide, in a vehicle lift, mechanical linkage including a pivot arm and a lifting arm, said arms being interconnected by a coupling link in such a manner that tension is exerted on said link as the vehicle lift is raised.

Yet another important object of this invention is to provide a vehicle lift which is portable as a result ofthe provision of a wheeled frame, is compact in overall size, and which has a low profile permitting placement thereof under essentially any vehicle and further, which is fluidoperated as by air, which fluid is available in virtually every location where such a lift would be utilized, thereby eliminating the need for an independent power source.

A yet further significant object of this invention is to provide in a vehicle lift, a safety lock assembly wherein the lift is retained in a raised position and inadvertent collapsing thereof is prevented, for the safety of the operator working under the vehicle which is lifted; there being means for releasing the safety lock assembly whereby rthe lift may be permitted to move to a fully lowered position.

Other objects of this invention will become apparent from the following specification and accompanying drawings, wherein:

FIG. 1 is a side elevational "view of the vehicle lift;

FIG. 2 is a fragmentary, substantially central, longitudinal sectional view of the vehicle lift;

FIG. 3 is a front perspective view thereof;

FIG. 4 is a fragmentary, sectional view taken on line 4 4 of FIG. 1; and

FIG. 5 is an enlarged, fragmentary sectional view taken on line 5-5 of FIG. 1.

The vehicle lift, broadly designated by the numeral 10, includes a base or frame 12 which is provided with front wheels 14 and a pair of rear caster wheels 16. Frame .12 supports a declining force fluid powered actuator 18 in the nature of a bellows which will be hereinafter more fully described, the actuator 18 being coupled with mechanical linkage broadly designated as 20, which linkage 20 carries means 22 for engaging the vehicle, said means being in the form of a pad or the like. A handle 24 is swingably coupled to the frame 12 at the end thereof opposite front wheels !14 whereby to permit the user of the lift 10 to readily position the same beneath a vehicle for lifting purposes.

The frame 12 has as its components a pair of side members 26, each of said side members having a straight portion 28 position toward the rear of the lift 10- and normally above the housings 30 for the casters 16, each of said side members then having a forwardly extending, inwardly inclined portion 32, said inclined portions converging toward a front member 34 which spans the normally forwardmost ends of side members 26 and serves as a housing for the axle of wheels 14. A rear member 36 spans the distance between the normally rearmost end of side members 26 whereby to cooperate with said members 26 and the front member 34 to present a polygonal wall for said frame. As is further evident from FIG. 1 of the drawings, the portions 28 lie in a substantially horizontal plane, while inclined portions 32 extend downwardly from the plane of portions 28 as they converge toward front member 34, all as is readily apparent from FIGS. 1 and 3 of the drawings.

Frame 12 also includes a pair of longitudinally extending, spaced apart, parallel braces 38 which are connected at their normally forwardmost ends to front member 34 as is clearly shown in FIG. 1 of the drawings, said braces joining at their normally rearwa-rdmost ends with a transverse brace 40, which brace 40 is parallel to frontmember 34 and spans the distance between side members 26 at a point intermediate the ends of said side members 26, the transverse brace 40 being secured at its ends to a depending flange 46 which extends downwardly from said side members 26.

Extending rearwardly from transverse brace 40 is a supporting plate 42 which is inclined with respect to the horizontal as best shown in FIGS. 1 and 2 of the drawings and which supports the normally lowermost end of bellows actuator 18. The rear marginal edge of plate 42 is supported by cross brace 44, which brace spans the distance between the pair of depending flanges 46.

The actuator bellows 18 has a flexible body 48 formed from reinforced neoprene or similar material, the body 48, is the embodiment chosen for illustration, being divided into two communicating compartments-by a centrally disposed, rigid ring 50, there also being a ring 52 at the lowermost end of actuator 18 and a ring 54 at the normally uppermost end thereof. A sealing plate 56 forms a bottom for actuator 18 and is attached to plate 42. as by suitable fastening means 58. Likewise, the normally uppermost end of bellows 18 is closed by a top plate 60, the top plate 60 being connected to the mechanical linkage as by a fastener 62.

An opening 64 formed in bottom plate 56 permits air under pressure to enter bellows 18 for the inflation thereof, said opening 64 being in communication with a pipe 66 which extends rearwardly from bellows actuator 18 and is coupled with a hose 68, which hose 68 extends throughout the length of handle 24, as best shown in FIG. 1 of the drawings, there being a suitable valve interposed therein and controlled by a lever 70' for delivering fluid under pressure to bellows 18, as when the lift is to be raised, or permitting air to be released from bellows 18 when the lift is to be lowered. A coupling 72 is provided on hose 68 at the free end of handle 24 so that said hose 68 can be quickly and easily placed into communication with a source of fluid under pressure such as, for example, the air supply normally found in a service station, garage, or similar establishment.

The handle 24 is pivotally attached to frame 12 as by a pin 74 which spans a rearwardly extending bracket 76, thereby permitting swinging of the handle to various positions with respect to the frame as, for example, from the full-line position, shown in FIG. 1, to the dotted-line position shown in FIG. 1. In order to adjust the angularity of the handle 24 with respect to the frame 12, a springloaded rod 78 extends along the interior of handle 24 and is coupled with a lever 80 at its upper end, there being a shiftable plate 82 coupled with the normally lowermost end of rod 78, which plate carries a pin 84 selectively engageable with the notches 86 in a detent plate '88, all as is clearly shown in FIGS. 1 and 2 of the drawings. Thus, through the utilization of lever 80, the handle 24 may be positioned in any one of a number of positions with respect to the frame 12 whereby to permit easy movement of the lift and positioning thereof beneath the vehicle to be lifted.

The mechanical linkage 20 includes a pivot arm 90', a lifting arm 92, a tension link 94 coupling said arms 90 and 92, and a leveling bar 96 interconnecting the pivot arm 90 and the means 22 for engaging the vehicle. The pivot arm 90 includes a pair of legs 98 and a web portion 100, the web portion 100 overlying the normally uppermost end of actuator 18 and consisting of a pair of

spacedapart planar members

102 and 104, the normally lowermost of said members being secured to the top plate 60 of the actuator 18. A sidewall 106 joins

plates

102 and 104 and has a pair of rearwardly extending portions 108 disposed at essentially the rear corners of substantially triangular web 100, said portions each receiving a pivot pin 110 by which links 94 are coupled to one end of pivot arm 90. The other end of pivot arm 90 is pivotally attached to the frame 12 as by pins 112 received by and between upstanding lugs 114, there being a pair of lugs 114 on each of the braces 38, all as clearly shown in FIG. 3 of the drawings.

The lifting arm 92 is pivoted to the frame 12 at the normally rearmost end of the lift 10 by means of a transversely extending pivot pin 116 which spans the distance between side members 32 as shown in FIG. 4 of the drawings. Lifting arm 92 is coupled to pivot arm 90 by links 94 through pivot pins 118, which pivot pins are secured to integral portions 120 of lifting arm 92, which portions 120 are disposed intermediate the ends of the lifting arm 92. A stop member 121 is carried by each portion 120', the stops 121 being in the path of travel of corresponding links 94 whereby the latter will abuttingly engage stops 121 to limit upward movement of linkage 20.

It will be noted that links 94 are connected at one end thereof to the pivot arm 90, as by pins 110, and at the other end thereof to lifting arm 92, as by pivot pins 118, the point of connection to the pivot arm being above the point of connection to the lifting arm whereby, as the lift is raised, tension is exerted upon link 94. It has been found that by careful selection of the specific pivot point locations such as 110 and 118, and the angular position of the links 94, the mechanical advantage of the lift 10 can be adjusted to create an increase in the mechanical advantage of the lift as the same is raised. This increase in mechanical advantage of the linkage is offset by the fact that the fluid powered actuator 18 has a declining force as it is inflated to an expanded, fully extended condition.

Such declining force is due to the fac that, as actuator bellows 18 is expanded by the introduction of fluid thereinto the cross-sectional area of the bellows 18 is reduced, thereby reducing commensurately the output force exerted thereby, this force, or load carrying capacity, declining as the effective diameter of the bellows is reduced due to the extension thereof.

Therefore, by using an actuator which has its highest force capacity at its initial stage of inflation, and a declining capacity as it is more fully expanded and extended, and coupling the same with a mechanical linkage 20 which has an increase in load capacity as it extends upwardly during raising of the lift 10, the load lifting capacity of the lift is substantially constant throughout the raising thereof. The lifting arm 92 could assume any overall configuration but, in the form chosen for illustration, includes a cover plate 122 of a configuration to fit within the confines of

members

26, 34 and 36 when the lift is in a lowered position, the plate 122 having a depending skirt 124 on both sides and the rear end thereof, the side skirts 124 each having suitably secured thereto as by welding or the like, longitudinally extending members 126, which members converge as the normally forwardmost end of lifting arm 92 is approached, said members being pivotally attached as at 128 to the means for engaging the vehicle.

Said vehicle-engaging means 22 includes a pad 130 which is designed to suitably engage the desired portion of the vehicle to be lifted, the pad being carried by a platform 132, which platform 132 has secured thereto a sleeve, carried by a pair of blocks 134, the sleeve receiving pin 128 to thereby pivotally couple members 126 with means 22.

Also depending from platform 132 are a pair of spacedapart ears 136 which pivotally receive therebetween, as by pin 138, the normally forwardmost end of leveling bar 96. The normally rearwardmost end of leveling bar 96 is pivotally attached to the pivot arm 90 as by a pin 140 spanning the distance between legs 98 of pivot arm 90, all as is clearly shown in FIG. 3 of the drawings. From the foregoing it will be appreciated that the vehicle-engaging means is pivotally carried at the normally forwardmost ends of leveling bar 96 and lifting arm 92.

The vehicle lift 10 is provided with a safety lock assembly 142 for preventing inadvertent lowering of the lift while the user is working beneath the lifted vehicle. The safety lock assembly 142 consists of a pair of spacedapart hangers 144 which are pivotally attached to the rearwardly extending portions 108 of the pivot arm 90, said hangers carrying therebetween a safety lock rod 146. A pair of spaced-apart catch plates 148 are carried by frame 12 which are secured to cross brace 44 and present an inclined series of notches 150.

Release mechanism 152 is provided for the safety lock assembly 142, said release mechanism including a swingable, U-shaped bar 154 which is coupled with a spring 156 and an operating handle 158. As will be apparent, the hangers 144 are free to swing as the lift 10 is raised and thereby will cause rod 146 to move along the inclined, notched edges of catch plates 148, the rod 146 remaining in essentially the position shown in FIG. 2 when the lift is raised. However, should the lift be inadvertently or accidentally lowered while the user thereof is beneath the vehicle, it will be appreciated that rod 146 would catch in the uppermost of notches and thereby prevent the lift from assuming a fully lowered position which might cause the vehicle to be lowered upon the user of the lift.

On the other hand, when it is desired to lower the lift 10 from any raised position, the same is moved upward until rod 146 swings out of a notch 150' when operating handle 158 is grasped to pull the same rearwardly. Handle 158 is locked in a releasing position as by engaging shoulder 160 with the frame, thereby causing bar 154 to be swung to a position against one of the plates 148, thereby closing notches 150 and, upon lowering of the lift, permitting the rod 146 to slide along the bight portion of bar 154 without becoming engaged in notches 150.

In operation, the lift 10 is moved to a position beneath a vehicle to be lifted, through the utilization of handle 24, wheels 14 and casters 16. A source of fluid under pressure is then coupled, through coupling 72 with hose 68 and valve control lever 70 actuated to permit air to enter bellows 18 whereupon the same is expanded, causing swinging movement of the pivot arm 90 about pivot point 112. This upward motion is transmitted to lifting arm 92 through link 94, causing a shifting upward movement of lifting arm 92 about its pivot pin 116, such shifting movement of the lifting arm 92 causing a commensurate upward movement of the vehicle-engaging means 22. A continuing constant upward lifting force is exerted on the vehicle-engaging means 22 through the actuator and linkage hereinabove described until such time as actuator 18 has reached its fully expanded, extended condition, or until such time as the supply of fluid thereto is terminated by valve lever 70.

When it is desired to bring the lift to a lowered position, it is only necessary to reverse the valve in hose 6-8 through actuation of lever 70, whereby the fluid initially contained within actuator 18 is permitted to escape to the atmosphere through an exhaust port in the valve, it being noted that safety assembly 142 must be first brought to a position whereby the rod 146 will not catch in any of the notches 150 as the lift is lowered.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:

1. A vehicle lift comprising: a frame; a generally declining force, fluid powered actuator in the form of a flexible bellows carried by said frame;

generally increasing force mechanical linkage coupled with said actuator, said increasing force mechanical linkage including a pivot arm swingable upon operation of the actuator, a lifting arm coupled with said pivot arm and shiftable in response to swinging movement of the pivot arm, and at least one link coupling said pivot arm with said lifting arm;

means carried by said linkage for engaging the vehicle;

and

means for placing said actuator in communication with a source of fluid under pressure whereby upon introduction of fluid under substantially constant pressure into said actuator said lift will be raised at a substantially constant load capacity.

2. A vehicle lift as set forth in claim 1, said link being connected at one end thereof to the pivot arm and at the other end thereof to said lifting arm, the point of connection of said link to said pivot arm being above the point of connection thereof to said lifting arm whereby said link is under tension during raising of the lift.

3. A vehicle lift as set forth in claim 2, said bellows actuator having the normally lowermost end thereof supported by said frame and the normally uppenmost end thereof in engagement with said pivot arm adjacent one end of the latter.

4. A vehicle lift as set forth in claim 3, the other end of said pivot arm being pivotally attached to said frame.

5. A vehicle lift as set forth in claim 4, said coupling link being connected to said one end of said pivot arm.

6. A vehicle lift as set forth in claim 5, there being a leveling bar interconnecting said pivot arm and said means for engaging the vehicle whereby to maintain the latter in a horizontal position during operation of the lift.

7. A vehicle lift as set forth in claim 6, there being a safety lock assembly for said lift, said assembly includ ing a lock bar swingably carried by said mechanical linkage and a catch plate carried by said frame, said bar being engageable with said plate for retaining the lift in a raised position.

8. A vehicle lift as set forth in claim 7, there being means for disengaging said bar from said plate whereby to permit said lift to be brought to a fully lowered position.

References Cited UNITED STATES PATENTS 2,070,960 2/ 1937 Phillips 254-93 2,585,856 2/1952 Schmeider 2542 3,319,532 5/1967 Pridham 9234 3,379,411 4/1968 Vandergast 2548 ROBERT C. RIORDON, Primary Examiner D. R. MELTON, Assistant Examiner U.S. C1. X.R. 2542, 8