LUBRICATION all the time
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-vvITH labour costs high and skilled labour at a premium, reduced maintenance of vehicles has never been more important than it is today. New models introduced often incorporate features having this object in mind—such as lubrication-free suspension systems and extended lubrication periods—but becoming more popular is the fitting of some form of automatic lubrication.
In the majority of cases, automatic lubricating equipment is fitted at the request of the buyer of the vehicle after it has left the manufacturer, but it is significant that Leyland has made this feature a standard fitting on the Atlantean rear-engined double-decker and on the Albion Lowlander. The increased popularity of automatic lubrication was confirmed at the recent Commercial Motor Show, when a cheek of exhibited vehicles showed that 75 were fitted with one of the two Tecalemit systems available, whilst a further 15 were equipped with Clayton Dewandre equipment. This was a fairly high proportion of the total vehicle exhibits, and was about twice as many as at the 1960 Show.
The savings in cost which must follow the fitting of automatic lubrication are not primarily the result of eliminating the need for men to pump lubricant into bearings. It is obviously far better to have continual lubrication—one or two shots of oil per mile to a bearing—than to have a large quantity of grease forced in every 1,000 miles or so. In the former case the bearing face is always evenly lubricated, whereas with periodic greasing the amount of lubricant present is steadily diminishing between servicing. It is also possible that certain bearings can be overlooked during the greasing operation and, very often, greaseways get blocked with solidified grease: many operatives omit to check that the grease injected always gets to the bearing face.
It can be said that a similar thing may happen with an automatically lubricated chassis by a pipeline becoming broken or stopped up in some way. This is perfectly true, but the point
is that the fitting of automatic lubrication equipment does not overcome the need for periodic inspection of the chassis. This should be one of the most important functions of persons carrying out greasing at routine maintenance periods and is still necessary even if automatic lubrication is employed. A bearing not getting sufficient lubrication will be obvious on inspection by the dryness of the bearing externally.
Whilst periodic inspection is still required, there is some cost saving due to the elimination of manual greasing. The main saving, however, is the cost of replacing parts because of the extended life of bearings and ancillary items as a result of the improved efficiency of lubrication.
Many claims of considerable savings in maintenance costs by having automatic lubrication have been made by operators. Figures of up to £800 in the working life of an eight-wheeler and of up to £300 in the case of a 7-tonner have been quoted by some operators, and it is reported that as much as £100 on the renewal of shackle pins in the life of an eight-wheeler can be saved. Another reason why automatic lubrication reduces wear is that, because the oil is injected at high pressure at frequent intervals, dirt and water are excluded from the bearing surface. With periodic greasing, it is often the case that grease left around the bearing collects grit and forms an abrasive material which can enter the bearing clearance.
As indicated by the increased number of vehicles fitted with automatic lubrication equipment, the use of such systems is becoming increasingly popular. As far as Tecalemit (Engineering) Ltd., is concerned, the value of the company's sales of this type of equipment has risen from £80,000 in 1955 to almost Lim. in the past year. Two systems are offered by Tecalemit: Syndromic, which was first produced in 1946, and AC.L., first made available in March 1959. The two systems are completely different in their method of operation although both are mileage controlled.
Syndromic is the more elaborate, and by suitable teeing of minor points a 60-unit pump available is capable of providing (71 complete coverage of an eight-wheel chassis. Costs of installations vary according to the number of points lubricated and range from £72 for a 14-unit to £202 for a 60-unit system. A.C.L. was introduced to cater for lighter commercial vehicles of up to 7-ton capacity and is designed to supply up to 30 points, the cost of a full system being about £50. In both cases the price includes installat:on at one of the Tecalemit fittings stations.
The main part of the Syndromic system is a pump assetribly driven by a belt from the propeller shaft of the vehicle to which the system is fitted. There are three models available—having 20, 40 and 60 pumping units—each of which can be supplied for anti-clockwise or clockwise rotation of the drive pulley.
Little Maintenance Needed
The pump assembly consists of a circular housing with individual pumping units Mounted around its periphery. These are connected to the chassis bearings being lubricated. Inside the housing there are one, two or three single-lobe operating cams, depending on whether the unit is for 20, 40 or 60 lubrication points. The operating cam revolves very slowly, being driven by a 2,00010 1 reduction gear train enclosed in a gearbox inside the driven pulley hub. For vehicles which do a small mileage at low speeds threeor six-lobe cams are available to give an increased supply of lubricant to the hearings. One of the features of Syndromic is that the pump units are available with four calibrations, to give 0.01, 0-015, 0-025 and 0.04 c.c.s output per stroke. The deciding factor in which output should be made use of is the size and type of the individual bearing, being lubricated. Actual lubricant requirements of all types of bearings to be found on a chassis have been calculated by Tecalemit.
Once the system is employed maintenance is fairly simple and consists primarily of a daily check of the oil level in the reservoir and a check every month of the belt tension. As stated earlier, the fitting of automatic lubrication should not mean that periodic inspection of the chassis is not carried out, and, when this is done, the bearings being lubricated should be checked visually to ensure that they are actually receiving lubricant. Tecalemit also recommends that every six months the piping and flexible tubing should be checked for damage and that the reservoir should be cleaned out every year.
In special cases where more than 60 lubrication points on a vehicle have to be connected up to one Syndromic pump, it is possible to arrange for one or more of the pumping units to supply a single line ring-main system. In this case the bearings connected to the ring-main are fitted with special metering units which proportion accurately the feed to each bearing from a total lubricant supply.
The cheaper A.C.L. system is much simpler than Syndromic and employs a low-torque pump driven from the vehicle's existing speedometer drive. Supply of lubricant to the pump is from a gravity-feed oil reservoir of about three pints capacity, and the oil pump is driven by a reduction gear train inside the housing to give about four pump impulses per mile, Nominal output is 0.11 c.c. per stroke at a pressure of about 250 p.s.i.
The lubricating oil is fed into a ring-main fitted around the inside of the chassis. Nylon tubing is used, and branches to the lubrication points on the chassis are taken from manifolds varying from one-way to four-way depending on the number of points in the immediate vicinity.
Deliveries Metered
Special meter units are fitted to the manifolds—one for each bearing to be lubricated. These are calibrated to deliver the correct amount of oil to the bearing, and a noteworthy feature of the system is that in the event of a branch line being damaged the functioning of the remainder of the system is not impaired. This is because the restriction offered by the meter unit is enough to maintain pressure in the ring-main regardless of the pressure in the branch lines or individual bearings. Uneven tightness of bearings will not cause incorrect metering, as the meter unit restriction is higher than that of any bearing manufactured to recognized commercial limits.
Maintenance of the system is extremely simple and consists of the same routine tasks as Syndromic, such as a daily check of the oil level in the reservoir and a periodic check that all points are receiving lubricant.
Oil consumed by the two types of system is about 1,000 miles per pint for A.C.L. and about 5,000 miles per gallon for Syndromic when fitted to a four-wheeled vehicle with 35 lubrication points. Both Syndromic and A.C.L. are intended primarily for rigid vehicles and, until a couple of years ago, had not been applied to semi-trailers and trailers to any extent. In fact, in 1960, only 200 or 300 of these vehicles were fitted with automatic Lubrication equipment, but last year the figure was over 2,000. The need for automatic lubrication equipment is probably greater on articulated than on rigid vehicles for, although there may not be as many points needing to be lubricated, a semitrailer is often moved around from vehicle to vehicle and in many cases does not get caught up with for maintenance at the right times.
To fill the need, Tecalemit offers two systems. One is the Midget Brentford system, which is completely independent of the tractor or tractive unit and allows trailers to be switched around the fleet. The pump is of the multi-unit type, one unit feeding one bearing and each being adjustable for output to suit the bearing load and area. Operation of the pump is linked to the brake system so that at each brake application all bearings on the chassis receive a supply of lubricant. The pumping unit is of the oscillating-drive type and has six delivery points so that one, two, three or four assemblies are coupled together, depending on the number of points to be fed. Oil consumption for a three-pump installation feeding 18 bearings is of the order of 10,000 to 12,000 miles per gallon.
The second system is designed for use where a trailer remains permanently coupled to its prime mover and is, in effect, an extension of the Syndromic system on the prime mover. It is known as the Syndromic/A.C.L, Trailer system and the supply of oil is obtained from the Syndromic pump on the tractor or tractive unit. The necessary number of pumping units are coupled together into one line and are taken to a self-sealing hydraulic hose coupling between the tractor and trailer. This feeds into a ring-main arranged with manifold blocks and metering units of the trailer portion and operates in the same way as the A.C.L. system described earlier.
Clayton Dewandre Co. Ltd., is the other main supplier of automatic lubrication equipment in this country. The company also has two basic systems, one similar in some ways to Tecalemit Syndromic, whilst the other is actuated by operation of the brakes on the vehicle to which it is fitted. These are known as the R.P. Multipoint Mechanical and R.P. Automatic respectively.
Clayton Dewandre Systems The R.P. Automatic Lubricator was developed many years ago by Clayton Dewandre in collaboration with Messrs. T. Rolland and H. Parker of Birmingham City Transport. The main part of the system is a pump unit which can be either vacuum or air pressure operated according to the braking system fitted to the vehicle. The vacuum or air pressure actuates a piston connected to the pumping mechanism which forces oil to one of the delivery ports located at the end of the unit. The feed is indexed to successive ports after each shot. By restricting the travel of the piston the quantity of oil delivered to the bearings can be adjusted to give from 0.05 to 0.1 c.c. per shot, although the same amount of oil is delivered from each feed point.
The standard R.P. Lubricator has 24 feed points which allow 23 chassis lubricating points to be fed, the 24th being taken back into the unit to feed the pump mechanism itself. It can also be made as a 12-point machine annular, in which case there are 11 points available for chassis lubrication.
The limitation of the R.P. Automatic Lubricator is that when applied to long-distance vehicles there is no regularity of the oil fed to each bearing: through towns where brakes are applied fairly frequently bearings will be well lubricated whilst on the open road with infrequent brake application, the bearings will get less and, in some cases, insufficient oil. This system is therefore more applicable to town and city bus services for which, of course, it was originally developed.
To provide an automatic lubrication system suitable for all .ypes of operation, the R.P. Multipoint Mechanical Lubricator was developed. With this system the oil supply is based on the nileage run by the vehicle, the pump unit being belt driven 'rom the vehicle's propeller shaft and designed to run at about 1.200 revolutions per mile. The drive shaft is geared to a worm haft in the pump unit which drives a worm wheel mounted on an assembly incorporating a face cam. This operates the main pumping plunger. Lubricant is forced past a non-return valve into one of the delivery lines through a feed arm which is indexed after each shut to the next delivery line.
The delivery points are located in the end of the pump unit in a series of circles, the layout being similar to that of the R.P. Automatic Lubricator. Delivery heads with 24 or 36 points are made and the pump unit can have a delivery head fitted on one or both ends. This means that by various combinations the pump can be suitable for lubricating 24 or 36 points with a single head or 48, 60 or 72 points when dual heads are fitted.
The amount of oil delivered to each bearing can be adjusted from 0.05 to 0.1 c.c. per shot—it will be the same at all points. Oil consumption will vary, of course, with the number of points lubricated but will be about 8,000 miles per gallon when an average delivery of about 0.075 c.c. per shot is set for singlehead type.
For trailer vehicles a Multipoint Lubricator on the tractor is fitted with a second low-lift face cam as with a dualhead pump. This is only possible with a single-head unit because, in the position that would be occupied by the second head, a cover incorporating a distributor valve is fitted. This valve is fitted in a line from the air-pressure or vacuum reservoir on the tractor to an air-pressure or vacuum-operated R.P. Automatic Lubricator on the trailer. Each rotation of the cam assembly in the tractor pump unit sends an impulse of air-pressure or vacuum to the trailer pump and one point of the trailer will be lubricated for each impulse.
As far as maintenance is concerned, the remarks included in the section on the Tecalemit equipment will apply also to the Clayton Dewandre systems.
A third concern engaged in making automatic lubrication equipment is Lubrication Equipment Ltd., 24 Derby Road, Liverpool, 20. Known as the M.I. Automatic Chassis Lubricator, it is similar in operation to Tecalemit A.C.L. A ring-main is used to supply manifold blocks at convenient points around the chassis into which are fitted patented flow-control units. The outlets of the units arc connected to points to be lubricated by nylon tubing. The flow control units determine the proportion of oil delivered to each point and in the same way as A.C.L., the amount of oil delivered does not depend on the fit of the bearings. In the same way, should a connection from a control unit to a bearing be damaged or broken it would not affect the oil supply to any of the other points being lubricated.
Delivery of lubricant with the M.I. system is in effect on a time basis. This is because the main pump unit is operated by an electric motor which is of constant speed and connected to the vehicle's electrical system—as long as the battery main switch or the ignition are on, lubricant is being delivered,