US2620897A - Chain drive with lubricating means - Google Patents

Description

e 9- F. w. SlMPKlN CHAIN DRIVE-WITH LUBRICATING MEANS Filed Aug. 6, 1951 Attorney I Patented Dec. 9, 1952 port; England; assignor to; Theltenold and Coventry -Ghain Company,v Limited, Didsbury,

England- Applijo atitm August 6, 1951 SeIial. 'Nn."240;-491- In Great Britain. Augnst 9',.1950

23Claims. 1.

Driving chainsiccmmonl yrun'round two wheels of different sizes andi are enclosed in a casing; When the :d'rive' i's arranged so that-the plan'e containing the axes of the two wheels over which it passes-is. horizontal it is usually a simple matter to lubricate the chain, because the bottom of thecasing forms an oil sump into which the larger wheel and thepart of the chain around it dip. If the plane containing the axes is at a small angle to the horizontal with: the larger wheel above the lower, the :lower. run of" the chain can-generallyrun through the pool of oil. In either case this pool is large enough to prevent any substantial amount of surging being set up as the chain travels through the oil. Sometimes, however, the drive runs at a greater angle to the horizontal, and, when this angle is from 30 to 80 with the small wheel at the bottom, there is usually only a small pool of oil at the bottom of the chain casing. If the chain is running at speed it is preferable for it not to dip into this pool of oil at the bottom of the casing, since if it did a foam would quickly form and the lubricating properties of the oil would be reduced. Accordingly in such cases a device is usually provided for raising oil from the pool and delivering it onto the chain. One such form of device includes a disc fixed to the shaft of the lower wheel of the drive and of diameter suflicient for its periphery to run in the pool of oil in the casing and pick up oil. This oil is then thrown off centrifugally more or less upwards onto a collector from which it drains onto the chain.

It is found that the use of such an oil-throwing disc also causes undesirable foaming of the oil, and it is an object of the present invention to provide an oil-throwing device which does not cause foaming.

One feature of this invention is that the disc is replaced by a small number (which may be one) of thin vanes which extend radially from the shaft of the chain wheel and each of which enters the pool of oil in the casing edge-on once during each revolution of the shaft. When a disc rotates in the pool of oil an area on each side is immersed in the oil all the time and lifts the surface of the oil in the neighbourhood of the disc. This is the cause of the foaming. When the disc is replaced by vanes, the corresponding area so immersed is never as great at any instant and the total area immersed throughout one complete revolution is much less. Accordingly the eddies in the oil due to viscous forces from the moving vanes are less and so less foaming occurs. Provided that the vanes are thin,

2 thEfiUE-Iflillgi produced by the entry of the. edge of a vane into the oil is negligible. It is ttound that one or two vanes are suflicient to'pi'ck'up'the oil required for lubrication "and ifmorethan four vanes are used" the reduction off'oaming'as compared'with a disc is slight.

In practice a driving chain and its lubricating deviceand casing are sold as a unit which may be usedtttdifi'rent inclinations to the horizontal. In the devices used hitherto, the oil is thrown upwards onto the underside of a collecting plate and runs down this to a trough which extends into the space between the upper and lower runs of chain. This trough is parallel' to the shaft carrying the disc which picks up the oil, and has a hole immediately above the lower run of the chain. Now if the collecting plate and trough are both at suitable angles when the whole drive is inclined at one angle to the horizontal, those angles will not be suitable when the drive is inclined at another angle to the horizontal.

It is a further object of the present invention to provide a collecting plate and trough which will cooperate with an oil-throwing device over a range of inclinations of the drive.

Another feature of this invention is that the collecting plate and trough can turn about a horizontal axis and can be held frictionally in positions most suited to the inclination of the casing.

The accompanying drawings illustrate the preferred embodiment of the invention. In these drawings:

Figure 1 is a side elevation of the lower part of the chain drive with the casing broken away on the line II in Figure 2; and

Figure 2 is an end elevation with the casing broken away on the line IIII in Figure 1.

The chain drive is inclined at about to the horizontal and the lower chain wheel 2 is somewhat smaller than the upper. The drive is enclosed in a casing 4 in which sufiicient oil is placed to form a pool 6 clear of the chain 8 passing round the chain wheel 2.

A boss I 0 is secured to the shaft I 2 of the chain wheel 2 and this boss carries a double vane ll, the tips of which enter the pool of oil edge-on in turn and then throw oil upwards, as indicated by the arrows I 6 or l8, according to the direction of rotation of the shaft 12. Each vane has a width about half the diameter of the circle swept out by their tips, so that the pool of oil 6 is only disturbed by the tip of a vane passing through it during about one-third of each revolution of the shaft l 2.

The oil thrown 'iupwards by the tips of the vanes clings to the underside of a collecting plate 20. The oil flows down the underside of the plate into a trough 22 and then through an outlet 24 in the bottom of the trough vertically above the lower run of the chain 8. Although the drive is shown inclined at 60 to the horizontal the same drive may be installed at any angle between about 30 and 80 to the horizontal and the shafts may rotate in either direction. To allow for this the collecting plate 20 and the trough 22 can be turned about a horizontal axis and in addition the collecting plate is formed as a Y, one or other side of which is used according to the direction of rotation of the drive. A threaded stud 26 on one end of the trough 22 passes through a lug 28 on the collecting plate 20 and then through one side of the casing 4. This stud receives a nut 30 and lock nut 32 and when the trough and collecting plate have been turned to the most suitable positions they are held by tightening the nuts.

What I claim is:

1. A chain drive adapted for inclined use and comprising, in combination, an upper and a lower chain wheel, a chain running over said wheels, shafts for said Wheels, a casing surrounding said chain and defining a sump for a pool of oil beneath said lower wheel, means adapted to throw oil upwards from said pool when said-drive is in motion, an inclined plate adapted to catch the oil thrown upwards on its lower face and a trough adapted to collect oil running down said lower face and to deliver said oil onto said chain, said plate and trough being mounted for independent rotation about a common horizontal axis and friction means being provided for holding said plate and trough in any selected position.

2. A chain drive adapted for inclined use and comprising, in combination, an upper and a lower chain wheel, a chain running over said wheels, shafts for said wheels, a casing surrounding said chain and defining a sump for a pool of oil beneath said lower wheel, a small number of vanes extending radially from the shaft of said lower wheel and adapted, when the drive is in motion, to enter said pool of oil edge-on in turn and to throw oil upwards, an inclined plate adapted to catch the oil thrown upwards on its lower face and a trough adapted to collect oil running down said lower face and to deliver said oil onto said chain, said Plate and trough being mounted for independent rotation about a common horizontal axis and friction means being provided for holding said plate and trough in any selected position.

3. A chain drive as claimed in claim 2 wherein said plate has a projecting lug and said trough is provided at one end with a threaded stud which passes in succession through said lug and said casing and receives a nut constituting said friction means.

F. W. SIMPKIN.

REFERENCES CITED UNITED STATES PATENTS Name Date Number Bartlett July 29, 1930

Images