US2578871A

US2578871A - Power tension elevating device

Info

Publication number: US2578871A
Application number: US683719A
Authority: US
Inventors: Woldring Egbert
Original assignee: ARROW PRODUCTS
Current assignee: ARROW PRODUCTS
Priority date: 1946-07-15
Filing date: 1946-07-15
Publication date: 1951-12-18
Anticipated expiration: 1968-12-18

Description

Dec. 18, 1951 E. WOLDRING 2,578,371

POWER TENSION ELEVATING DEVICE I Filed July 15, 1946 Z SHEETSSHEET l \NVENTOB WW Dec. 18, 1951 E. WOLDRING 2,578,871

POWER TENSION ELEVATING DEVICE Filed July 15, 1946 2 SHEETS SHEET .2

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Patented Dec. 18, 1951 UNITED STATES PATENT OFFICE POWER TENSION ELEVATIN G DEVICE partnership Application July 15, 1946, Serial No. 683,719

The present invention relates to a power tension elevating device. It is primarily designed for the purpose of moving and elevating goods from a lower to a higher position by means of an endless conveyor belt, the upper run of which carries the goods and has an upward inclination, the angle of which may be varied, so that goods placed at the lower part of the device, are moved upwardly with the belt and away from the position where loaded on the belt to desired elevated positions.

Such type of device is subject to different loads carried, with the result that the section or upper run of the belt which carries the loads, has a tendency to sag between the lower and upper rollers over which it runs, with greater sag with the greater loads. With my invention, the conveying belt is power driven and a novel construction is provided such that upon increase of load carried by the belt, this requiring an increase in power to drive said belt, the belt is automatically tensioned to a greater degree, thus compensating for and overcoming entirely or in large measure, the sagging of the upper run of the belt which is carrying the load of goods being elevated.

My invention is directed to a very novel, compact and effective power driven transmission of a belt conveyor for increasing the tension of the belt with increases of loads carried thereby. The belt at all times is subjected to a normal tension, but upon increase in the weight of the load carried, such tension is increased and the run or section of the belt to which the load is directly applied, has its tension increased, also the belt is decreased in tension upon lessening the weight of the load, whereby by means of my invention, the belt as to tension is made self-corrective for all conditions of-all operation with respect to the load which is being elevated thereby.

An understanding of a preferred construction embodiment of the invention may be had from the following description, taken in connection with the accompanying drawing, in which:

Fig. 1 is a side elevationof a machine made in accordance with my invention, I

Fig. 2 is a fragmentary enlarged'similar section of the lower portion of the machine, and

Fig. 3 is a fragmentary plan view of the machine at the lower end portion thereof, a part of the conveyor belt being broken away for better disclosure.

Like reference characters refer to like parts in the different figures of the drawing.

In the construction disclosed, the conveyor frame preferably-has spaced sides,-each includ- 5 Claims. (01. 198208) ing an upper bar I of metal of a suitable angular cross section and a like lower bar 2, said bars diverging from each other toward the lower end of the machine. At their upper ends the bars are connected together and the sides of the conveyor frame may be secured together at their upper ends by a transverse plate 3. Suitable braces 4 interposed between the side bars I and 2 between their ends may be used and, of course transverse connecting members may be used, each to connect the two sides of the frame together. Both of said upper and lower bars I and 2 at their lower ends are connected with end plates 5 of a generally semi-circular form, between which tubular cross rods 6 extend, secured at their ends to the plates, to make a strong relatively light rigid frame construction.

A lower tubular bar I likewise extends between the plates 5 and to it tubular rods 8 may be secured which extend forwardly in a generally horizontal direction and receive telescopically therein rods or tubes. Said tubes 8 and 9 may be adjusted to different positions relative to each other and held in any selected position .by any suitable releasable securing means. The rods 9 at their forward ends are connected to a horizontal axle l0 upon which end wheels II are mounted. Tubular rods l2 are also connected at their lower ends to the axle l0, and extend upwardly in a forwardly inclined direction and telescopically receive tubes or rods l3 therein, the upper ends of which are connected with the frame of the machine near its upper end. The telescopic parts l2 and I3 may likewise be adjusted to different positions with respect to each other and releasably held in any selected position. Therefore, the inclination of the frame to the horizontal is subject to a relatively wide range of adjustment.

A drive roller I4 is mounted on a central hori zontal shaft [5, said shaft being substantially midway between the upper and lower edges of plates 5. A U-shaped fork or stirrup !6 has the arms thereof connected at the ends of the shaft l5. From the cross connecting portion of the stirrup It, a frame I I extends forwardly, the front end of the frame reaching approximately to mid-position of the first described main conveyor frame and having a pivotal connection at is to suitable supporting blocks I!) carried by the main frame.

An electric motor .29, or other suitable prime mover, is mounted onthe frame ll at its upper end and through a series of sprocket wheels and chains 2| and 22, may drive the roller I4 at a much reduced speed compared to the speed of rotation of the motor. At the upper portion of the main frame above and slightly forward of the roller M, an idle roller 23 on a horizontal shaft is mounted between the plates 5, its uppermost points being located a short distance above the adjacent upper sides or edges of the upper main frame bars I. A roller 24 is mounted at the upper end of the main frame. Around the drive roller l4 and the two

idle rollers

23 and 24 an endless conveyor belt 25 extends. Preferably at its outer side it is equipped with a plurality of spaced transverse slats or ribs, as shown.

The weight of the frame H, the roller I4 and the other associate parts carried by the frame tensions the belt to some extent but such tension is increased. Rods 26 have around each of them, between their ends, a coiled compression spring 21, the upper end engaging against a washer and nut 28, and the lower end against a shelf 29, one extending from each side of the frame I?! throughwhich the lower ends of rods 26 pass. The upper ends'of the rods bear against a transverse frame member 39 extending between the upper bars I of thewmain frame. Said springs 27 increase the tension in the belt and itmay be varied by adjusting the nuts 28 to normally take care of stretching or wear which occurs.

With the construction described, the goods to be moved and elevated will be placed upon the upper run or section of the belt conveyor 25 adjacent the roller 23. The weight of the goods puts a strain upon the belt conveyor so that if the roller It had its shaft 15 fixed at its ends or only movable a limited distance, the upper run of the belt 25 under the weight of the goods carried would sag between the

rollers

23 and 24 with the greatest degree of sag substantially midway between said rollers. The movement of the upper run of the belt being away from the roller 23 the rotation of the driving roller I4 is in a clockwise direction to cause such movement. It drives the belt by frictional engagement therewith. Such rotation of the roller 14 in said direction and the frictional engagement of the roller with the belt. tend to cause the roller and the frame I! to move in a downward direction about the axis of the pivots 18. The downward movement increases the tension on the belt and to a large degree, eliminates the sag in the upper run or, section of the conveyor. Further, because with an increase in weight of goods carried, the power required to be delivered to the roller I4 is increased, the frictional engagement of the roller with the belt 25 will likewise be increased. with an increase in tension in the belt. Thus the belt tension is increased with an increase in .the load carried, to thereby maintain the upper run of ,the belt in a taut condition and with a substantially complete ehmination of movement sag therein. The floating drive roller M at the inner side of the belt, through its ability to move downwardly, and its frictional pull upon the lower run of the belt causing it to thus move in proportion to the power transmitted to the roller through the belt, serves to balance against the sagging of the belt under the weights carried, greater weights or loads causing a proportionately greater pull on the belt-to remove such sag.

The construction described is very practical and effective, very useful in service and is readily and economically produced.

The invention is defined in the appended claims and is to be considered comprehensive f all forms of structure coming within their scope.

I claim:

1. A structure as described comprising an elongated frame support, means for maintaining said frame support in an inclined position with one end higher than the other, an idle roller mounted to turn about a horizontal axis at the higher end of said frame, a second idle roller mounted to turn about a horizontal axis at the upper side of and adjacent the lower end of the frame, a driving roller located at the lower end of the frame below the second idle roller, means for driving the driving roller, means on which the driving roller is mounted movably connected with said frame whereby the driving roller may move in a generally vertical direction with reference to its adjacentidle roller, and an endless conveyor belt passing around all of said rollers, the pressure of the driving roller acting against said conveyor belt to impart tension thereto, said driving roller f-rictionally driving said conveyor belt and automatically moving in a downward direction upon weight'applied to the belt at-the upper side thereof between said idle rollers therebyincreasingthe tension in the belt with increases of said weight.

2. In a structure as described, an elongated frame, means for adjustably supporting said frame in a position inclined to the horizontal with one end higher than the other, an idle roller mounted to turn about a horizontal axis at the higher end of the frame, a second idle roller mounted to turn about a horizontal axis at the upper side of and adjacent the lower end of the frame, a driving roller mounted to turn about a horizontal axis, an elongated support at one end of which the driving roller is mounted, means pivotally connecting the opposite end'of said support to the frame at anintermediate' position inthe length of the frame, means for'continuously driving said driving roller, and an endless conveyor belt passing: around all of the rollers lengthwise of said frame at its upperside and within which said driving roller is located in frictional driving engagement therewith.

3. A construction as defined in claim 2, saidmeans for driving the driving-roller comprising a prime mover mounted 'uponsaid support for thedriving roller adjacent its pivotally connected end, and speed reducing driving means between said prime mover and driving roller.

4. In a construction as described, an elongated supporting frame, means for adjustably elevatingone end of the frame to a higher level than the other end, an idle roller at the higher end of the frame mounted to turn about a horizontal axis, a second idle roller mounted to turn on a horizontal axis adjacent the other end of the frameroller to the upper idle roller, the frictional engagement of said driving roller with said belt varying with loadapplied to the upper run of the belt whereby the tension of the belt is increased by said engagement of the driving roller therewith, upon increasesof loads carried from adjacent the lower idle roller to the higher idle roller.

5. A structure as described comprising, an elongated support having a receiving end, and.- a

5 delivery end, leg means for supporting said delivery end at a higher level than the receiving end, a first idle roller mounted at said delivery end of the support, a second idle roller, said second roller mounted at the receiving end of the support, a driving roller below and adjacent said second idle roller and positioned outwardly therefrom in a direction away from said first idle roller, means for driving said driving roller, an endless conveyor belt passing around all of said rollers, and means for mounting said driving roller for up and down movements toward and away from said second idler roller, combined with means acting upon said driving roller normally tending to move it away from said second idle The following references are of record in the file of this patent:

FOREIGN PATENTS Country Date Great Britain Mar. 7, 1919 Number