US2095041A - Automobile lift - Google Patents

Description

Oct. 5, 1937. E. B. THOMPSON 2,095,041

AUTOMOBILE LIFT Filed Dec. 2, 1935 2 Sheets-Sheet l -Fjvgl. 7

Oct. 5, 1937.

E. B. THOMPSON AUTOMOBILE LIFT 2 Sheets-Sheet 2 Filed Dec. 2, 1935 4 w M w w z vUu In. 0 \\\\S a 6 n 3 1 i 7 a W M26? W w wwz Patented Oct. 5, 1937 UNITED STATES AUTOMOBILE LIFT Elmer B. Thompson, Des Moines, Iowa, assignor to Globe Machinery & Supply Company, Des Moines, Iowa, a corporation of Iowa Application December 2, 1935, Serial No. 52,444

4 Claims.

My invention relates to that class of lifts in which the lifting mechanism is contained wholly above the floor surface on which the lift is mounted, as distinguished from so-called hydraulic lifts in which the lifting piston and cylinder must be mounted below the floor surface.

My object is to provide a lift of this character made of few parts, of rugged construction, and

which will not be injuriously affected by the kind of work to which it is subjected in normal use.

A further object is to provide a lift of this character which includes as a safety device a means for automatically locking the automobile supporting frame in any position of its up and 5 down movement and making it capable of such up and down movement only when the driving motor is operated.

A further object is to provide a lift of this character constructed of detachable, self-contained units which may be readily and quickly assembled by unskilled labor.

A further object is to provide a lift of this character in which there is no obstruction between the uprights which project above the corners of the main frame, so that automobiles may be driven on one end of the lift and off the other; and further in this connection to provide a lift in which the four posts which support the corners of the lift are free and independent of each other and which need not be secured in any manner to the floor nor connected with each other, and whereby the floor may be left clear of all obstructions, except where the posts themselves engage it.

Other objects will appear in the following speci- 35 fication.

My invention consists in the construction, arrangement and combination of the various parts of the lift whereby the objects contemplated are attained, as hereinafter more fully set forth,

40 pointed out in my claims, and illustrated in the accompanying drawings, in which:

Figure 1 shows a top or plan view of a lift embodying my invention, with parts broken away to show structural details;

Figure 2 shows a side elevation of same with the 'ift frame in its elevated position;

Figure 3 shows an enlarged detail sectional view on the line 3-3 of Figure 1;

Figure 4 shows an enlarged detail side eleva- 50 tion, partly in section, illustrating a portion of the main frame, one of the hollow uprights on the main frame and one of the upright posts slidingly mounted therein, and illustrating the driving motor and the power transmission gear mech- 55 anism connected therewith;

Figure 5 shows a side elevation of the power transmission mechanism and self locking mechanism associated therewith, taken on the line 5-5 of Figure 4;

Figure 6 shows an enlarged detail vertical sectional view illustrating a portion of one of the hollow uprights, a portion of .the supporting post therein, and illustrating the rack and pinion mechanism for elevating the main frame, and the safety pawl mechanism; and

Figure 7 shows a sectional view on the line 1-1 of Figure 6.

Referring to the accompanying drawings I shall first describe what I have termed the frame upon which an automobile may be driven and supported. The frame herein illustrated is of the variety known as the free wheeling and comprises two parallel spaced apart structural steel H bars Ill. At the ends thereof there are the transverse beams l5, preferably made of H steel rails, firmly fixed to the rails l0. Obviously, trough shaped wheel supporting members may be applied to this main frame for causing it to operate in the manner of a "roll-on lift.

Mounted in the outer side of each rail I is a shaft I2 mounted in bearings l3 fixed to the rail l0, having a beveled pinion l4 at each end.

'At each end of the structure there is an end member comprising aa supporting beam I with a hollow upright H5 at each end thereof. Near the central portion of the beam ii there are clamping plates l1 securely bolted to the beam I5, and projecting over the adjacent portions of the main frame to which they are detachably bolted. Mounted in suitable bearings on the inner side of the beam I5 is a power transmitting shaft I8, with a beveled pinion I9 thereon. These parts are so arranged and proportioned that when the main frame is placed in proper position relative to the end frame to receive the bolts for connecting them, then the pinions l4 and I9 are in mesh.

On the interior of each of the hollow uprights there is fixed to the shaft It! a pinion 20, for the purposes hereinafter made clear. and opposite pinion 20 is a roller 2| mounted in the hollow upright.

On one of the end frames I have mounted an electric motor indicated generally by the reference numeral 22 and provided. with a control switch lever 23, of ordinary construction, for stopping and starting and reversal of the motor in its various adjustments.

For the purpose of driving the power shafts which operate the pinions 20 from the motor, and for locking these power shafts in any position of movement of the lift, I have provided the following mechanism: Fixed to a hollow upright 44 below the motor 22 is a shaft 24, and surrounding this shaft 24 is a rotatable sleev2i. Fixed to the shaft 24 is a large gear wheel 28, and adjacent to it and parallel with it is a somewhat similar large gear 21 fixed to the sleeve 26 and rotatable with the sleeve. This gear wheel 21 has one or more less gear teeth on it than the gear 24, for purposes hereinafter made clear. Surrounding said gear wheels is a casing 24 rotatably mounted on the sleeve 25, and this casing is provided with'a pulley 20, which is connected by a belt 30 with the motor.

Rotatably mounted in suitable bearings in the casing 28 are two shafts 3i, and flxedto each shaft is a pinion 32 in mesh with the gear wheel 28, and another pinion 33 in mesh with the gear wheel 21; and due to the fact that the gear wheel 24 is stationary and the gear wheel 21 is rotatable, and that the pinions 32 and 22 are both fixed to the same shaft, then due to the fact that the gear wheel 21 has less teeth than the gear wheel 24,, the sleeve 25 will be locked against rotation in any (Erection, except when the casing 24 is rotated by the motor, and the speed of rotation as applied by; the belt to the casing will be very greatly reduced as applied by the pinion 21 to the sleeve 25. This planetary gear arrangement and its locking feature is well known and its mode of operation is well known. Power is transmitted from the sleeve to the shaft ll through the pinions 24, 25 and 26.

For the purpose of supporting the main frame upon a floor I haveprovided four upright posts, each comprising a base 31 to rest upon the floor and an upright member 38 slidingly fitted within the adJacent hollow upright. At the side of the post 38 adjacent the pinion 20, as shown in Figure 6, I have mounted a rack bar 3!. This rack bar is held in position by means of plates 40, shown in Figure 7, fixed to the post 38 and overlapping the sides of the rack bar. This rack bar is capable of limited up and down movement relative to the post within said plates 40, and its upward movement is limited by the shoulder 4|, shown in Figure 6. At one end of the said rack bar I have formed a depression and omitted several teeth from the rack bar, as shown at 42 in Figure 6. It will be understood that there is one oi the posts provided with the rack bar It in each of the four hollow uprights and that there is also a pinion 20 and a roller 2| in each of the hollow uprights. The operation of this part of my invention is as follows:

When the main frame has been elevated to the point where the pinions 20 enter the depression at 42 thesepinions may continue to rotate, should the operator fail to shut off the motor, but they cannot function to elevate the main frame beyond its normal upward limit of movement; and in the event that this should occur while the motor is still running, the pinions 24 will produce considerable friction and jarring upon the rack so that the attention of the operator will be drawn to it and so that the operator will then shut off the motor. However, no"

accident can occur on account of such failure to shut oi! the motor. A somewhat similar effect will take place when the pinion 24 is moving downwardly relative to the rack, and if the motor continues to operate after the main frame has reached its downward limit of movement, then a further rotation of the pinion 20 will cause the rack to move upwardly a short distance relative to the post, and thereby place the rack out of operative contact with the pinion. At the same time it would create some noise, thereby directing the operator's attention to it so that he may shut 03 the motor. When, however, the movement of the pinion is reversed, the rack 39 will slide down by gravity or be drawn down by the pinion 20 to its lower limit of movement where the rack teeth will be in engagement with the pinion and the lift will be elevated in the normal manner.

As an additional safety measure I have provided an automatic means for stopping the electric motor when the lift is at either limit of its movement. This means comprises a rod 43 fixed at its lower end to the base 31 and extended upwardly and slidingly mounted in the switch control lever 23. Two stop devices 49 are fixed to this rod 43, one being so positioned that when the lift is at its upper limit of movement it will engage the switch control lever 23 and move it to position for stopping the electric motor, and the other one is so positioned on the rod 43 that, when the lift is moving downwardly it will engage the switch control lever 23 and automatically move it to position for stopping the motor.

I have also provided an additional safety element for preventing accidental downward movement of the main frame, as follows: On each of the hollow uprights I6 I have pivoted a pawl 45 projected through an opening in the hollow upright and designed to normally engage the rack 39, as shown in Figure 6. These pawls at the four hollow uprights are preferably connected by suitable bell crank levers 46 and 41, so that they may all be manually moved to unlocking position by means of a lever 48 mounted on one of the hollow uprights.

In practice I prepare my improved lift for shipping and transportation in units, the main frame constituting one unit, the two endframes constituting another unit, and the four posts being in separate units. In this manner the lift may be placed in a small and compact space and can be readilyshipped and handled.

When it is desired to erect my improved lift upon a display floor or the like, the operator simply bolts the plates I 1 to firmly connect the plates I1 to the main frame, theyhaving previously been bolted to the end frames, then the four posts are inserted in their positions within the hollow uprights, and the lift is ready to operate.

One of the advantages of my improved lift is that, with my improved construction there is no necessity for having any cross members or braces at the tops of the hollow uprights as each end frame is an independent unit of suilicient strength to withstand the strains and stresses to which they are subjected. Hence, an operator may drive on one end of the lift and off of the other, and the lift may be raised and lowered without any danger of having any part of the automobile strike against any such obstruction.

Furthermore, with my improved construction the upright posts are simply rested upon the floor and need no fastening to the floor or connection 'one with the other, because the hollow uprights serve at all times to hold them in vertical positions, and this I accomplish by having the hollow uprights extended far enough above the main frame to form a bearing or guide for the posts spaced a considerable distance above the main frame, and also a bearing or guide for the posts at about the level of the frame, and the posts are of such length that a 'sumcient length of each post is contained within the hollow frame, even when the lift is in its elevated position, to perform this guiding action and keep the posts in upright positions against twisting strains.

With my improved construction I am enabled to use on the upright posts large and rugged rack bars and large and rugged pinions within the upright posts, and also large and rugged gear transmission mechanism from the motor to the pinions 20. These parts are all relatively slow moving on account of the gear reduction in the power transmission device and, hence, are not subjected to injurious wear in ordinary use and are not likely to be broken.

In practice an automobile is driven on to the lift and the motor started in the direction required for elevating the main frame. The main frame then engages and elevates the automobile in the ordinary manner, and in the event that the operator should neglect to stop the motor the main frame is automatically stopped when it reaches the desired upper limit of its movement by the entrance of the pinions 20 into the depression 42. In the event that the motor should be stopped at any point throughout the elevation of the main frame, the main frame will be automatically locked against either up or down movement by the planetary gear transmission device, and can only be moved upwardly or downwardly when the motor is operated.

In addition to this, I have provided an additional safety feature against accidental downward movement of the main frame by the pawls 45 which engage the large and rugged rack bars 39, and these pawls may be easily and quickly thrown out of operation by the operator when it is desired to further lower the lift.

I claim as my invention:

1. An automobile lift comprising a frame adapted to receive and support an automobile, four hollow uprights fixed to and extended upwardly from the frame and being free from cross braces or the like above the frame and whereby automobiles may be freely driven over both ends of the frame, four posts telescopically mounted in said hollow uprights and being disconnected with each other and held against tilting movement by said hollowuprights, a rack secured to each post, a pinion in mesh with the rack and carried by the hollow upright, means for jointly operating the pinions to raise and lower the frame relative to the posts, means for positively limiting the upward movement of the frame relative to the p sts which consists in forming a depression without cog teeth in each post at the point where the pinions reach their upper limit of movement, and means for stopping the downward driving force of the pinions upon the racks when the frame is at its lower limit of movement, which consists in mounting the racks upon the posts with a limited up and down sliding movement and whereby when said downward limit of movement is reached the driving power of the pinions will raise said racks above driving contact with a pinion.

2. An automobile lift comprising a frame adapted to receive and support an automobile, four hollow uprights fixed to and extended upwardly from the frame and being free from cross braces or the like above the frame and whereby automobiles may be freely driven over both ends of the frame, four posts telescopically mounted in said hollow uprights and being disconnected with each other and held against tilting movement by said hollow uprights, a rack secured to each post, a pinion in mesh with the rack and carried by the hollow upright, means for jointly operating the pinions to raise and lower the frame relative to the posts, means for positively limiting the upward movement of the frame relative to the posts which consists in forming a depression without cog teeth in each post at the point where the pinions reach their upper limit of movement, and means for stopping the downward driving force of the pinions upon the racks when the frame is at its lower limit of movement, which consists in mounting the racks upon the posts with a limited up and down sliding movement and whereby when said downward limit of movement is reached the driving power of the pinions will raise said racks above driving contact with a pinion, said racks also being so constructed that upon a movement of the pinions in the direction required for raising the lifts the racks will move into position for engaging the pinions.

3. A lift device of the class described, comprising an upright, a weight carrying frame slidingly mounted upon and guided by the upright, a pinion carried by the frame, means for rotating the pinion, and a rack slidingly mounted for up and down movement upon said upright and in position to mesh with said pinion, said parts being so shaped that when the frame reaches its upper limit of movement the pinion will have moved to position where it will not engage the rack teeth so that continued rotation of the pinion after the frame is elevated to said position will not tend to elevate it further, said rack being of such length that when the frame is being moved downwardly and reaches its lower limit, a continued rotation of said pinion will elevate the rack to position with the pinion out of operative contact with the rack.

4. A lift device of the class described, comprising two uprights, a weight supporting frame, two pinions carried by the frame, means for rotating the pinions, the said frame and posts above said pinions being telescopically and slidingly connected so that when the frame has reached its upper limit of movement it will be supported by said uprights, a rack for each upright slidingly mounted therein for limited vertical movement relative to the upright and having teeth thereon from its lower end portion to a point at the upper limit of movement of the frame, said teeth being normally in mesh with said pinions but being out of operative engagement with the pinions when the frame is at its upper limit.

ELMER B. THOMPSON.

Images