US3024891A

US3024891A - Continuous vertical lift

Info

Publication number: US3024891A
Application number: US833422A
Authority: US
Inventors: Hewlett M Sawrie
Original assignee: Individual
Current assignee: Individual
Priority date: 1959-08-13
Filing date: 1959-08-13
Publication date: 1962-03-13
Anticipated expiration: 1979-03-13

Description

March 13, 1962 H. M. SAWRIE CONTINUOUS VERTICAL LIFT Filed Aug. 13, 1959 3 Sheets-Sheet 1 INVENTOR I HEWLETT M. SAWRIE u awumf gomzfim ATTORNEY March 13, 1962 H. M. SAWRIE 3,024,891

CONTINUOUS VERTICAL LIFT Filed Aug. 13. 1959 5 Sheets-Sheet 2 HEWLETT M. SAWRIE ia/monf AT ORNEY March 13, 1962 H. M. SAWRlE CONTINUOUS VERTICAL LIFT 5 Sheets-Sheet 3 Filed Aug. 13, 1959 1"- I l-lTlI l 385 INVENTOR HEWLETT M. SAWRIE 4414220725 Malian ATTORNEY atet dice 3,Z4,89 l Patented Mar. 13, 1962 3,024,891 CONTINUOUS VERTICAL LIFT Hewlett M. S'awrie, 616 Lindsay St, Chattanooga 3, Tenn. Filed Aug. 13, 1959, Ser. No. 833,422 6 Claims. (til. 18-154) This invention relates to a continuous vertical lift for boxes and the like and more particularly to such a lift in which the path of return of the lift to a loading position occupies a minimum of space.

Prior to this invention, the following types of vertical lifts have been used for the purpose of lifting or lowering boxes, bales, drums, sacks or other containers of different commodities:

(1) Double chain rigid carriage, in which rigid platforms are attached to two endless loops of chain, which pass over sprockets on head and tail shafts. These carriages remain in horizontal positions, except at the top and bottom, where they go around the head and tail shafts radially.

(2) Double chain pendant carriage, in which a carriage of the pendant type is suspended between two endless loops of chain in the same manner as the cars of a Ferris wheel are suspended. The pendant stays in a horizontal position while going around the head and tail shafts and requires a pit to be able to load close to the floor.

(3) Single strand pendant carriage, in which a carriage f the pendant type is swung from a single endless loop of chain, requiring a pit for loading close to the floor.

(4) Reciprocating lift, having a platform which travels up and down like an elevator, stopping to load and unload at the top and bottom, and/or at intermediate levels. It is usually operated by a cable from a winding drum, or by a chain passing over a top sprocket with a counterweight on the other end of the chain.

(5) Reciprocating lifts, having two platforms attached to the ends of a chain or cable, which passes over a top sprocket or sheave. One platform goes up while the other comes down and each platform counterbalances the other.

All of these types of vertical lifts, with the exception of the single platform reciprocating lift, require enough room for the travel of a platform going down, as well as for the travel of one going up. Such lifts require floor space equal to more than twice the area of the platform or carriage used.

All of the foregoing types of vertical lifts require guides for the platforms or carriages, as well as for the chains, and the two reciprocating types require guides for the platforms and counterweights, just as does an elevator or durnbwaiter.

In addition, all of the above types of vertical lifts require special loading and unloading mechanisms, which are generally expensive and complicated.

One object of this invention is to provide a continuous vertical lift having endless flexible lineal members carrying platforms, which are rigid in their horizontal carrying positions but which bend to occupy a minimum of space during their return to a loading position.

Another object is to provide such a lift in which the loading is automatic from either an inclined rollway or a treadmill continuously rotated by the lineal members of the lift.

A further object is to provide such a lift in which the unloading is automatic to an inclined gravity rollway or to a power conveyor.

Other objects and advantages of the invention will be apparent from the following description, taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a side elevation showing one embodiment of this invention in which parts of endless chains carry platforms which are rigid in one direction, as When lifting, but

are bendable in the other direction, as when descending for the next load, and also showing a loading treadmill and loading and discharging rollways;

PEG. 2 is a partial front elevation on the line 22 of FIG. 1;

FIG. 3 is a horizontal section on the line 3-3 of FIG. 1;

FIG. 4 is a partial vertical section on the line 44 0! FIG. 1;

FIG. 5 is a perspective view showing details of one form of a platform, stage or flight;

FIG. 6 is a top plan view of a modified form of a plat form; and

FIG. 7 is a perspective view of the modified form of platform shown in FIG. 6, disclosing details of its con struction.

In the drawings, a framework, generally indicated at 1, of structural steel is provided to support the lift for any height desired. For clarity of illustration, many portions of the framework are omitted. The framework supports at its top in a horizontal position a head, or drive, shaft 2 driven by a suitable source of power, not shown. Di-

rectly below the drive shaft 2 at the bottom of the structure is a take-up shaft 3 which is parallel to the drive shaft. A lower front shaft 4, located at the front of the lift and slightly above the take-up shaft 3, is provided, this shaft being parallel to the drive shaft 2 and to the take-up shaft 3.

A pair of endless flexible

lineal members

5 and 6, preferably chains, are in mesh with

sprockets

7 and 8 keyed to the drive shaft 2. From the

sprockets

7 and 8 on the drive shaft, the

chains

5 and 6 pass vertically downward to sprockets 9 and 10 on the take-up shaft 3. From there, the

chains

5 and 6 pass forward and up a slight incline to

sprockets

11 and 12 on the lower front shaft 4. After passing over the

sprockets

11 and 12, the

chains

5 and 6 pass under and around

idler sprockets

13 and 14, mounted on

stub shafts

15 and 16 supported by the frame 1. From the

idler sprockets

13 and 14, the

chains

5 and 6 pass vertically upward to a pair of coaxial idler sprockets 17, also mounted on stub shafts supported by the frame and from those sprockets the

chains

5 and 6 pass horizontally back to the

sprockets

7 and 3 on the drive shaft 2 to complete their cycles of travel.

A second pair of

chains

21 and 22 are meshed with

sprockets

23 and 24 keyed to the drive shaft 2. The

main carrying chains

5, 6, 21 and 22 are all of exactly the same length and all travel in the same planes, except in the lifting shaft area where the platforms are carried in horizontal position. The

chains

21 and 22 pass vertically downward from the

sprockets

23 and 24 to sprockets 25 and 26 on the take-up shaft 3, around which they pass forward and slightly upward to sprockets 27 and 28 on the lower front shaft 4-. After passing around the sprockets 2'7 and 28, the

chains

21 and 22 move horizontally to the rear of the lift, where they pass under and around

idler sprockets

29 and 30, from which they move vertically upward to return to the

sprockets

23 and 24 and complete their cycles of travel.

Connected between the pairs of

chains

5, 6 and 21, 22 are a plurality of spaced platforms, stages or flights, generally indicated at 31. As indicated in FIG. 1, the pairs of

chains

5, 6 and 21, 22 have portions located in spaced, parallel planes in the load-carrying portion of the lift. Thus, the main carrying

chains

5 and 6 are in one plane and the main carrying

chains

21 and 22 are in another plane spaced from the first plane and parallel thereto. As shown in FIG. 5, for each platform 31, the

main carrying chains

5, 6, 21 and 22 have

A2 attachment links

32, 33, 34 and 35 attached thereto at the same horizontal level, when the chains are in their load-carrying position. A flat steel mounting bar 36 is attached to the

A2 attachment links

32 and 33 and a similar fiat steel mounting bar 37 is attached to the

A2 attachment links

34 and 35. A pair of spaced, parallel,

platform chains

31A and 31B are connected between the

flat bars

36 and 37, adjacent to their ends. Each platform chain is connected to the fiat bar 36 by means of an A2 attachment link 38A, from which the platform chain is made up of alternating roller links 39 and M-1 attachment links 40, having spaced pairs of upstanding lugs. At its other end, each

platform chain

31A and 31B is connected by a roller link 39 to another A2 attachment link 38B, by means of which it is attached to the -fiat bar 37.

The lugs of each pair of M-l attachment plates 40 have aligned, spaced, openings 41 therethrough, as shown in FIG. 5. Between the spaced lugs of each pair of M-l attachments 40, there is placed a bar segment, bar or block 42 having an opening 43 therethrough. (See FIG. 3.) The opening 43 is in alignment with the openings 41 in the lugs of the M1 link 40 and the bar segment 42 is of the same length as the spacing between the openings 41 in adjacent M-l links 40. The openings 43 are centrally located in the bar segments 42 and their ends abut, being vertical and fiat. Between corresponding M-l attachment links 40 on the two laterally spaced

platform chains

31A and 31B, rods 44, or free rollers having shafts, are attached. The rod, or shaft of the roller, is machined to fit the openings 41 in the lugs of the M-1 attachment 40 and they also pass through the openings 43 in the bar segments 42. When assembled, the rods, or shafts of the free rollers, are riveted in place in the M-1 attachments links 40. The bar segments 42 rest against the tops of the adjoining roller links 39, thereby preventing movement of the roller links in one direction. Also, as already stated, the fiat ends of the bar segments 42 abut against each other, thereby further preventing the bending of the

platform chains

31A and 31B in one direction. The use of rollers in the platform, in place of rods, facilitates unloading of the platform at the top or at intermediate points.

As each platform 31 travels upward to the top of the lift, the

main carrying chains

5, 6 pass around the idler sprockets 17. At the same time, the

main carrying chains

21, 22 travel around the

sprockets

23 and 24 on the drive shaft 2. The

platform chains

31A and 31B at the same time begin to pass around idler rollers or

sprockets

45, 46 on the drive shaft 2. The

main carrying chains

5, 6 move horizontally to carry their end of the platform 31 from a position adjacent to the idler sprockets 17 to the idler rollers or

sprockets

45, 46 on the drive shaft 2. During the horizontal movement, a box or other article B is automatically moved off the lift onto a gravity rollway or power conveyor 73 for unloading.

Since the bar segments 42 are pivoted on the upper or outer portions of the M-1 attachment links 40, above the roller links 39 when the platform is horizontal, as shown in FIG. 5, the roller links are free to pivot inwardly relative to the bar segments 42, which flake outwardly with respect to each other as they pass around the

idler rollers

45 and 46. The platform is free to revolve around the

idler rollers

45 and 46 and goes vertically downward with the

main carrying chains

5, 6, 21 and 22, in substantially the same plane with them. At the takeup shaft 3, the platform 31 passes around idler rollers or

sprockets

47, 48 and then passes around similar idler rollers or

sprockets

49, 50 on the lower front shaft 4. The idler rollers or

sprockets

45, 46, 47, 48, 49 and 50 keep the two

chains

31A and 31B of each platform in line with the

main carrying chains

5, 6, 21 and 22 and prevent slack from forming in the platform chains at the points of bending around the shafts. At the head or drive shaft 2, the idler rollers or

sprockets

45, 46 maintain the horizontal portion of the platform 31 level while it is approaching the turning point about the drive shaft,

thus preventing the platform from falling onto the drive shaft, as it would do if the idlers were omitted.

At least one, and preferably all, of the

sprockets

11, 12, 27 and 28 on the lower front shaft 4 for the

main carrying chains

5, 6, 21 and 22, are keyed to the lower front shaft to rotate it. Inside of the rollers 49, on the lower front shaft, as shown in FIGS. 2 and 3, there are two

sprockets

51, 52, keyed to the lower front shaft 4. Meshed with these

sprockets

51, 52 are a pair of

endless chains

53, 54 of a treadmill, generally indicated at 55. As indicated in the drawings, the

endless chains

53, 54 of the treadmill are spaced from each other and a series of equally spaced rollers 56 are connected between the

chains

53, 54 of the treadmill. The other ends of the

treadmill chains

53, 54 pass around

sprockets

57, 58 on a rear treadmill shaft 59. The treadmill has a slight incline for automatic loading of articles from an adjacent inclined gravity rollway or power conveyor 60, each article, such as a box B, rolling down the rollway 60 onto the treadmill 55 up against a gravity actuated stop 61 or against a rear portion of the framework. The stop 61 may be pivotally mounted on the frame so that it is lifted upward as the platforms 31 rise past it and then falls back down into position to stop the next box.

The

sprockets

51, 52 drive the

treadmill chains

53, 54 in proper timing or indexing with the four

main carrying chains

5, 6, 21 and 22, so that the bars or rollers 44 of each platform 31 fall between, mesh with or interdigitate with the rollers 56 of the treadmill 55, as the platform moves around the sprockets on the lower front shaft 4.

As the

chains

5, 6 move from the

sprockets

11, 12 on the lower front shaft 4 to pass around the

idler sprockets

13, 14, the

chains

21, 22 continue to travel horizontally until they reach the

idler sprockets

29, 30 at the rear of the lift. When the front and rear

flat bars

36, 37 of the platform reach the points of vertical travel of the

main carrying chains

5, 6, 21 and 22, which they do at the same time, the

chains

5, 6 pass around the

idler sprockets

13, 14 and the

chains

21, 22 pass around the

idler sprockets

29, 30. The platform 31 then begins to rise and, due to the construction described above, maintains a level, load-carrying position. At this point, the bars or rollers 44 of the platform rise up from their positions in between the rollers 56 of the treadmill and lift the box B from the treadmill automatically. Limit switches may be provided, if desired, to stop the lift momentarily if the commodity is only partially in the loading position when the platform comes up from between the rollers of the treadmill. When packages or boxes of uniform dimensions are being loaded, the loading can be made continuous by setting the rate of travel of the lift to match the feed of the loading conveyor or rollway 60, so that a package is waiting for each platform or flight when it arrives.

In the modification illustrated in FIGS. 6 and 7, there is no change in the basic structure of the lift, nor in the path of travel of the

main carrying chains

5, 6, 21 and 22. The modification relates only to the type of platform used and to the elimination of the treadmill 55, which is replaced by stationary rollers projecting from the sides of the structure. In the modified form of platform, the flat steel mounting bars 36, 37 are attached through the A2 links 32, 33, 34 and 35 to the

main carrying chains

5, 6, 21 and 22, as in the other form of the invention. As before, the points of attachment of the flat steel mounting bars 36 and 37 are such that the two bars will be in the same horizontal plane when the platform is in carrying position. To the centers of the two bars is connected a double width chain 62. The double chain may be attached to the flat steel mounting bars 36, 37 by means of a double bent lug attachment 62A at each end of the double chain, these being either two A2 attachments or one K-2 attachment. The double chain 62, with the double bent lug attachments 62A, is as long as the platform generally indicated at 63,

or the distance between the pairs of

chains

5, 6 and 21, 22. The construction of the double chain includes, after the first double bent lug attachment 62A, two roller links 64, then three straight lug plates 65 of the M-1 attachment type, then two roller links, and alternately so on, until the correct length is obtained, with a final double bent lug attachment 62A at the other end.

As in the other type of platform, the M-1 attachment plate links 65 have spaced lugs extending upward therefrom, the lugs of each set having aligned openings 66 therethrough. Bar segments, bars or blocks 67, of shapes and sizes similar to those of the bar segments, bars or blocks 42 in the other form of the invention, have centrally located openings 68 therein, aligned with the openings 66 in the lugs of the M1 attachment plate links 65. As before, the bar segments 67 are of lengths equal to the spacing between the centers of adjacent sets of M-l attachment links 65 and have fiat vertical ends, abutting against each other. Rods 69 of appropriate diameter are placed through the openings 66 in the M1 links 65 and through the openings 68 in the bar segments 67 and extend on opposite sides of the double chain 62, in approximately equal lengths on either side.

Steel, plastic, composition or rubber tubes 70 are then placed over both ends of the rods 69 and washers and cotter keys 71 are placed on the ends of the rods 69 to hold the tubes in place. The tubes 70 provide carrying surfaces which are above the tops of the lugs of the M-1 links 65 and form a level carrying surface. A rod is also attached to each of the double bent lug attachment links 62A, by which the double chain 62 is attached to the flat steel bars 36, 37 and tubes 70 are also placed over the ends of these rods.

With the double chain 62 at the center, the rods 69 with their tubes 70 constitute fingers or slats, forming a projecting cantilever shelf on either side of the double platform chain 62.

For loading onto this type of platform, a plurality of spaced rollers or roller fingers 72 are mounted on heavy shafts projecting inwardly horizontally from both sides of the frame 1. The rollers 72 are spaced apart distances equal to the center spacings of the rods 69 of the platform 63, but are staggered between the rods when the platform is in a horizontal position. The rollers on each side of the frame are thus substantially coaxial with the rollers on the opposite side. The rollers projecting from the sides of the frame 1 are long enough to pass between the rods 69 of the platform 63, with their ends close to the double chain 62 at the center of the platform, but not in contact with it.

These stationary rollers 72 are preferably placed in a line having a slope equal to the normal inclination of a gravity roller conveyor, so that the commodity will roll into the lift on the projecting rollers, as from the inclined rollway 60, to rest against the rear stop 61 and to wait for the next platform 63 to pick the commodity up off the rollers, as the platform passes upward between the rollers.

With this modified type of platform and loading station, the treadmill 55 is eliminated. In place of the idler rollers or

sprockets

45, 46 on the drive shaft 2, the idler rollers or sprockets 4'7, 48 on the take-up shaft 3 and the idler rollers or sprockets 49, St) on the lower front shaft 4, there is on each of these shafts, at its center, an idler roller or double sprocket, not shown, to support the double chain 62 of the platform 63 at the turning point and thus to prevent sagging or misalignment. Obviously, of course, the single through shaft 59 at the rear of the treadmill in the other type is also eliminated.

Unloading from the platform 63 to the gravity rollway or power conveyor 73 at the top of the lift is accomplished in the same manner as in the case of the platform 31.

The advantages of this modified form of platform are as follows:

(1) Economy of manufacture for use in light duty lift applications never before possible and to compete with the inclined belt conveyor, which is normally used in the absence of an economical lift, or where space is not a factor.

(2) Loading stations can be easily placed at almost any vertically spaced position on the standard lift, by appropriately positioning the rollers projecting from the lift sides. Additional loading stations can be inserted to fold up or out, as required, at any point.

A lift made in accordance with this invention is equally as etfective for lowering articles as it is for elevating them, by reversing the motor and thus the direction of rotation of the drive shaft 2, and reversing any other controls used with it. The unloading rollway or power conveyor 73 would be replaced by a loading rollway, with loading synchronized with the top positions of the platforms. The loading rollway or power conveyor 60 would be replaced by an unloading rollway or power conveyor and the treadmill 55 at the bottom would either be reversed or eliminated or located at the top of the lift. In the modified form, rollers 72 could be used for unloading, instead of loading, if desired.

The sides of the lift can be varied in all three dimensions to almost any reasonable limits to suit the commodities to be handled. This unit is much more suitable for larger, oversize, platforms than are the other types of vertical lifts mentioned above. The capacity of this lift is limited only by the size and strength of the chains used and by the strength of the structural framework.

A modification of the basic structure is that the

platform chains

31A, 31B and 62 may be replaced by heavy flexible belting or hinged metal belts, to the upper surfaces of which are attached a series of blocks or slats creating a shelf which is rigid in only one direction normal to the shelf.

Advantages of a continuous vertical lift made in accordance with this invention are as follows:

(1) It provides for continuous handling of commodities, one after the other, on horizontal platforms, which change to vertical positions at the top for the return trip and thus take up less room. This lift requires very little more floor space than the area of one platform. This feature enables the lift to be installed in close areas and saves valuable floor space for its user.

(2) Because of the manner in which a platform folds around the base shafts and sprockets, the loading position may be very close to the floor, rarely requiring a pit for installation. This feature saves on installation costs, pit drainage, and fabrication costs. It also facilitates any future relocation of the lift, as the fioor need not be disturbed by making a pit, as is required with other types.

(3) Chain guides are required only in the taller systems and chain guides are not even required in units up to about eighteen feet in height.

(4) When a platform reaches the top of the unit, it changes its direction of travel from vertical to horizontal and moves the commodity horizontally onto the attached gravity or power conveyor at the unloading point. The platform folds over the head shaft, as water falls over a waterfall, between the head shaft and the attached receiving conveyor, making the transfer from the lift to the receiving conveyor completely automatic.

Limit switches may be provided to stop the lift if the upper or lower receiving conveyor becomes completely loaded.

(5) By means of a free roller treadmill or loading station, the commodity may flow into the lift at the base and wait to be picked up by a platform, with the free rollers of the treadmill turning under the commodity, which is stopped against a stop plate or solid plate in the lift. Since the platform meshes with the rollers of the treadmill until it is ready to lift, the platform automatically picks the commodity up off the treadmill. With pack-ages of uniform size and shape, this loading can be made continuous by setting the travel of the lift to match the feed of the lower conveyor, so that a package is waiting for each platform.

(6) This lift will load and unload continuously, like a pendant type of lift, but is less complicated and can be built at a lower price, without requiring the additional guides needed for the carriages of the pendant lift.

7) Light models are possible for use with lightweight roller conveyor and skate wheel conveyors, at the ends of packing lines and assembly lines, to raise the commodity over passageways and up to overhead conveyors or to upper floor levels. These models can be constructed at a much lower price than can other types previously offered.

(8) By use of the modified loading platform and side mounted roller loading stations, loading and unloading can be arranged at various points up and down the lift structure.

It will be apparent to those skilled in the art that various changes may be made in the invention, without departing from the spirit and scope thereof, and therefore the invention is not limited by that which is shown in the drawings and described in the specification, but only as indicated in the appended claims.

Iclaim:

1. A lift comprising two pairs of endless flexible lineal members, each pair having a vertical portion in one plane parallel to and spaced from the plane of a vertical portion of the other pair, other portions of said pairs of lineal members being in the same planes, a plurality of platforms spaced from each other along said lineal members, each of said platforms including at least one flexible platform support connected and suspended between said pairs of lineal members and a series of members of rectangular cross section attached to the platform support on the same side thereof and forming a flat surface, said platform being rigid against the force of gravity when it is between the portions of the pairs of lineal members in spaced planes but being endable to lie in the same planes with other portions of the pairs of lineal members, and means for continuously driving said lineal members in the same direction.

2. The invention according to claim 1 in which the lift include-s a treadmill driven by at least one of said lineal members, said treadmill comprising a pair of spaced endless chains and a series of equally spaced rollers supported between said chains, said rollers being positioned within the rectangular members of the platform while the platform is coincident with the treadmill.

3. The invention according to claim 1 in which the lift has two side frames, each supporting a series of spaced horizontal rollers on stub axles, the rollers of each series being substantially coaxial with the rollers of the other series and extending closely adjacent to the rectangular members of the platform while the platform is coincident with the rollers.

4. A lift comprising two pairs of endless flexible lineal members, each pair having a vertical portion in one plane parallel to and spaced from the plane of a vertical portion of the other pair, other portions of said pairs of lineal members being in the same planes, a plurality of platforms spaced from each other along said lineal members, each of said platforms including at least one flexible platform support connected and suspended between said pairs of lineal members and a series of bars attached to the platform support on the same side thereof and forming a flat ledge, said ledge being rigid against the force of gravity when it is between the portions of the pairs of lineal members in spaced planes but being bendable to lie in the same planes with other portions of the pairs of lineal members, and means for continuously driving said lineal members in the same direction.

5. A lift comprising two pairs of endless flexible lineal members, each pair having a vertical portion in one plane parallel to and spaced from the plane of a vertical portion of the other pair, other portions of said pairs of lineal members being in the same planes, a plurality of platforms spaced from each other along said lineal members each of said platforms including at least one chain connected and suspended between said pairs of lineal members, said chain including a series of links pivoted to each other and blocks attached to the links on the same side thereof and forming a flat support, said support being rigid against the force of gravity when it is between the portions of the pairs of lineal members in spaced planes but being bendable to lie in the same planes with other portions of the pairs of lineal members, and means for continuously driving said lineal members in the same direction.

6. An elevator comprising two pairs of endless chains adapted to travel in the same direction, each pair of endless chains having a vertical portion in one plane parallel to and spaced from the plane of a vertical portion of the other pair, other portions of the pairs of endless chains being in the same planes, the first of said pairs of chains forming loops entirely within the loops formed by the second of said pairs of chains, a plurality of platforms spaced from each other along said chains, each of said platforms including at least one flexible platform support connected and suspended between said pairs of endless chains and a series of members of rectangular cross section attached to the platform support on the same side thereof and forming a fiat ledge, said platform being rigid against the force of gravity when it is between the portions of the pairs of lineal members in spaced planes but being bendable to lie in the same planes with other portions of the pairs of lineal members, and means for continuously driving said chains.

References Cited in the file of this patent UNITED STATES PATENTS 2,828,002 Sawrie Mar. 25, 1958 FOREIGN PATENTS 465,746 Germany Sept. 25, 1928