US3481448A - Tray lifter - Google Patents

Description

Dec. 2, 1969 E. ROTHSCHILD 3,481,448

TRAY LIFTER Filed Dec. 22, 1967 2 Sheets-Sheet l INVENTOR. Edgar Rgthschild hw/AW ATTORNEYS.

Dec. 2, 1969 E. ROTHSCHILD 3,481,448

TRAY LIFTER Filed Dec. 22. 1967 2 Sheets-Sheet 2 INVHVTOR. Edger Rothschild by (y ATTORNEYS.

United States Patent US. Cl. 198-136 2 Claims ABSTRACT OF THE DISCLOSURE The invention relates to a three conveyor system for transporting trays horizontally then vertically, from one floor to another for example, and then horizontally again when the trays have reached the height desired, all without abruptly changing the direction of the trays at any point and without stacking the trays.

This invention relates to a device for taking on, lifting or lowering and discharging of trays, particularly trays of the type used in cafeterias and restaurants connected with institutions such as hospitals where said trays are loaded with food-stuff in one area and then must be delivered to another higher or lower area.

In restaurants connected with hospitals and similar institutions, the food is prepared in the kitchen which is at one level, is loaded onto trays of a size which is suitable for one patient and then must be delivered to another floor or level before being given to the patient or other customer. Mechanical devices for lifting such trays from one floor to another have been developed but such devices, based mostly on the principle of the dumbwaiter, require that the tray or trays be delivered thereto in one direction, horizontally for example, then the direction of motion of the tray and its contents is sharply changed to a vertical direction, and finally after the vertical motion comes to a halt the tray is removed in another horizontal direction. Thus in being delivered from one level to another the tray and its contents (part of the contents usually being liquids), is stopped and started several times. Attempts to speed up the feeding of such trays to and removal of such trays from the lifting device necessarily results in spilling and splashing of the liquid contents of the trays. Also the feeding of trays to such a lifting device must be intermittent since a second tray cannot be fed onto the lifting mechanism until the previous tray has been lifted up to completely clear the oncoming tray.

Among the objects of the present invention is to provide a device which substantially continuously takes on a series of trays, feeds them upwardly or downwardly and thence horizontally at the desired level, all without any sudden changes in direction.

The objects of the invention are attained by connecting a horizontal conveyor means with a lifting or lowering device of the type having a pair of spiral tracks winding about a vertical axis, and connecting the latter with a second horizontal conveyor at the desired discharge point. Means are provided to automatically force the tray from thespiral tracks onto the discharge conveyor and such means can be attached at various points with respect to the spiral tracks to vary the discharge area as desired.

The trays are pushed along the spiral tracks by a series of rods held on a rotating spider and suspended from above or projected upwardly from below so that said rods can pass between the tracks at all levels when the spider is rotated.

In the accompanying drawing which illustrates, by way of example, a constructional form of the invention:

FIG. 1 is an elevational view, partly in section of the device of the invention.

Patented Dec. 2, 1969 FIG. 2 is a top view of the device of FIG. 1.

The device as a whole comprises one or more horizontal loading conveyors 10, the spiral conveyor with a vertical axis 20 and one or more unloading conveyors 50, 51. The loading and unloading conveyors are suitably belt type conveyors. The loading conveyor 10, for example, comprises an endless belt 11, held between two rollers 12 and 13, the latter roller being rotatably mounted within the cage formed in the spiral conveyor 20 between the drum 21 and series of vertical supports 22 thereof.

The spiral conveyor 20 comprises the drum 21 fixed upon the top surface 23 of the frame structure 24, 25. The drum 21 is suitably reinforced from the inside by caps 26 and 29 and rings 27 and 28. Attached to the outer surface of the drum 21 by welding for example, are a series of brackets 31-1 to 3113, etc., which are so arranged that a helical spiral track 32 of uniform pitch may be supported thereby. Extending down through the drum 21 is the shaft 33 which is rotatably mounted in bearings 34 and 35 positioned adjacent the central openings in caps 26 and 29. The lower end of shaft 33 is connected mechanically by means 36, illustrated diagrammatically, by which said conveyor 10 is driven from said shaft 33. Suitable means including the bevel gears 37, 38 are provided to positively rotate the shaft 33.

Attached to the upper portion of shaft 33 is the spider 39 containing the plurality of arms (in this case six) 41, 41-1, 41-2, 41-3, 41-4 and 41-5 on the ends of which the rods 42, 4 2-1, 42-2, 42-3, 42-4 and 425 are attached. On rotation of the spider 39, the rods 42 to 42-5 move around the drum 21 in the space outside of track 32 and inside of track 43 (to be described below).

Secured to the rim of the top surface 23 of the support 24, 25 are a plurality of uprights 22-1, 22-2, etc., forming the cage 22. The uprights 22-1, 22-2, etc. are further reinforced by means of reinforcing rings 41-1, 44-2, 44-3 and 44-4. Secured to the uprights 22-1, 22-2, etc., are a plurality of brackets 45-1 to 45-13 on which the spiral track 43 is mounted to parallel the track 32.

The tracks 32 and 43 can be formed of any material which preferably has a low coefficient of friction. Suitable materials are plastics such as polyethylene, polypropylene, Teflon, polyvinyl chloride, polycarbonates, nylon, etc. Although shown as being flat in shape the tracks can in fact be made with the cross sectional shape of a T or an I or may have plurality of reinforcing ribs on the under or upper sides thereof. Ordinarily, trays containing a single meal are not very heavy and a rugged track is not necessary. If desired, tracks formed of a series of rollers such as used in roller conveyors may be employed. The pusher rods 42 to 425 are preferably positioned just slightly outside of the imaginary cylindrical surface which bisects the space between the two tracks 32 and 43 so that any tendency that the pusher rods have to turn the trays away from the exact spiral path, tends to turn such trays toward the central drum 21 so that, in effect, the trays are guided by the tracks 32 and 43 and occasionally by the surface of drum 21.

The trays can be discharged at almost any desired point between two adjacent uprights 22-1 to 22-11 in the area adjacent the spiral tracks by afiixing the discharge angle piece 60 to the drum 21 in the path of the tray at the region where the discharge is desired. Said angle piece 60 comprises a pair of cars 61, 62 which pass through predetermined holes in the drum 21 and are clamped on the inside of the drum. The sloping surface 63 of said angle piece 60 is adapted to contact the edge of the tray and as the tray is squeezed between the rod 42 and the surface 63 it is guided between the two uprights 22-2 and 22-7 of FIG. 2, for example, where it is picked up by conveyor belt 50 and transported horizontally.

The features and principles underlying the invention Q described above in connection with specific exemplifications will suggest to those skilled in the art many other modifications thereof. It is accordingly desired that the appended claims shall not be limited to any specific feature or details thereof.

I claim:

1. An apparatus for transporting a series of loaded trays in a continuous manner, first in a horizontal direction thence vertically and finally horizontally without abruptly changing the direction thereof comprising a horizontal belt conveyor, spiral conveyor means to take the trays from the belt conveyor and transport them vertically in a spiral path and a second horizontal belt conveyor for taking said trays from said vertical conveyor,

said spiral conveyor means comprising a cylindrical drum adapted to support the first of a pair of spiral tracks in a position spaced from the outer surface thereof,

a cage structure arranged concentric to and outside of said cylindrical drum, means extending from said cage structure to support the second of said pair of spiral tracks in a position extending inwardly from said cage toward said drum and parallel to put spaced from said first track,

spider means supported to rotate on a vertical axis which is concentrically with respect to said drum, said spider means including spider arms extending above the space between said pair of tracks,

a plurality of pusher rods one afiixed to each of said spider arms extending substantially the full length of the space between said tracks whereby rotation of said spider means causes at least one of said rods to push a tray positioned on said track so that said tray moves on said spiral tracks,

discharge means having a sloping surface which projects into the path of a tray travelling on said spiral path, said discharge means being positioned opposite the second horizonal belt conveyor whereby a tray pushed into contact with said discharge means passes onto said second belt conveyor.

2. The device as claimed in claim 1 wherein said pusher rods are adjusted to extend just outside of the imaginary cylindrical surface bisecting the space between the pair of spiral tracks.

References Cited UNITED STATES PATENTS 1,085,852 2/1914 Duncan l98--212 1,177,502 3/1916 Ewald 198-212 EVON C. BLUNK, Primary Examiner ROGER S. GAITHER, Assistant Examiner US Cl. X.R.

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