Robey's Stearn Wagon.
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A Fine Five.-ton Steamer, of Well-known and Popular Type, but Possessing Many Original and Useful Features.
Robey and Co., Ltd., of Lincoln, had had several years of engineering experience 50 years ago. The company's first steam vehicle was built in 1870, since which time it has manufactured tractors and traction engines almost continuously, and the name Robey is as well known to users of this class of machine as is any. Of recent date, comparatively is this C0112-• pany's decision to manufacture commercially a steam wagon of the type which is understood by that term to-day. Our readers will remember that the Smithfield Show of 1514 was the first occasion on which public exhibition was made of a Robey steam wagon, and this journal, in the issue dated 10th of December of that year, was able to publish the first description of that wagon. Our reference on that occasion, embodied as it was in a, short review of the exhibits at the Agricultural Hall, was of necessity a brief one. Convenient opportunity for going more thoroughly into detail has not presented itself until now, and meantime, although we observe that a few minor improvements . have been effected since our previous reference, in the main the design is unaltered.
Robey an Overtype.
It is customary to classify steam wagons under two heads, overtype and undertype. The former refers to those in which the engine is bolted on the top of the boiler ; the latter is usually constructed with the boiler well in the front of the vehicle, the engine being carried below the frame, and slightly behind the driver's seat. The Robey steam wagon. is of the former class. It is a well-known type, and its utility is proven. It is not, therefore, necessary for us to devote valuable space to a detailed, tecbnical description of its general arrangement. Rather shall we direct attention to novelties of design observable in the Robey, of which there are several, and which mark the Robey machine as being an advance upon previous designs of this type of vehicle. Incidentally, many of these improvements are the subject of patents. General Individual Characteristics.
The first of these characteristics of individuality, as they might be termed, which strike one is the arrangement of the control, which is a near approach to that of the petrol wagon. The steering wheel, robustly constructed, as is usual on a steam wagon, nevertheless bears a strong family likeness to that component as found on a petrol wagon. The hand brake, the foot brake, the change-speed lever, throttle-valve lever, arid the lever for high-pressure working are all convenient of access to one man, the driver ; he sits to the right of
theboiler and has a very good "driver's eye" view. The second man, in the case of the Robey wagon, has practically nothing to do but stoke, and. on those occasions, few and far between, when the differential needs to be locked, he sh9uld effect this operation.
Three-point Suspension and Ackermann Steering.
The next of these noticeable features is to be seen on the front axle. Here may be found two important items worthy of consideration. The steering is on the Ackermann principle ; that is to say, each wheel is carried on a short stub axle, and each stub axle is carried at its inner end by a pivot on the front axle. The two stub axles are coupled by a transverse rod, and steering is effected by means of another coupling rod extending from the arm of one stub axle to a worm and wheel steering gear.
Robey and Co. Ltd., is firmly. of opinion that this type of steering gear is much better than the chain gear with centrally-pivoted front axle. Another feature of the front axle is to be observed in the manner of the support of the chassis upon it. Shackles at each end of the front axle c4rry a spring. The front end of the boiler rests on the spring, a bracket extending beyond and carrying a pin which passes through an elongated hole in the centre of the front axle. Reference to our illustration, specially taken to demonstrate this feature will clarify the text. The effect Of this arrangement is to give to the frame three-point suspension and to allow very considerable latitude to the chassis in respect of oscillation sideways without imposing undue strain on the framework, One of our illustrations is from a photograph of a wagon with one hind wheel in a road depression ; it demonstrates this feature.
Unusual Brake Gear.
Mention has been made of the hand and foot brake and their convenience of access. The brake gear, as a matter of fact, is another typical Robey feature. Both of these brakes take effect on drums bolted to the rear road wheels. The hand brake is an internal expanding,. the foot brake an external contracting one. Both sets of brake gear are fully compensated. Both brakes take effect on the same drums. The design of the internal brake shoes is the subject of a patent, as each pair of shoes is compensated in such a manner that each individual shoe must exert the same pressure on the drum. Reference to our illustration will disclose the fact that in the first place, each shoe is centrally pivoted ; secondly, that surroundmg the brake cam is a floating piece, square in form. This ensures the cam pressing equally on both shoes.
When it is intended that the wagon shall draw a trailer, an additional screw-operated brake is ‘. provided for the trailer. By means of a special arrangement of guide shoe for the trailer brake cable, this leaves the wagon in the centre of the rear cross-member, and not, as is frequently the case, to one side. Increased efficiency is claimed for this arrangement.
Whilst examining the• brakes, one naturally observes the special design of the road wheels. The construction of these important components embodies a east-steel centre of special design, a wooden fences, and surrounding that a specially designed steel rim which can be adjusted for shrinkage of the wooden felloe. Attention is directed to the spoke section of the wheels. These are U shaped, the curved part of the U being external and exposed to view, the hollow portion faces the wagon. The result is a wheel of good appearance, equalling in this respect that of the hollow oval-spoked type, whilst the openness of the casting is of great service in securing uniformity of thickness of metal and ease of manipulation in the foundry. The drive to the rear wheels is tsy means of a couple of pins as in traction-engine practice, consequently both wheels are immediately removable for purposes of tire renewal when necessary, or for any other reason.
Mention has been made of the differential locking gear. This also is the subject of a Robey patent. On the standard wagon it is orerated by ineans of a lever accessible only from the ground. On the wagon we examined, the footplate operating gear was fitted; this is an extra. In either case, the locking is effected by a sliding claw type of clutch meshing with suitable recesses in the differential case. The arrangement is simple, effective and strong.
The boiler fitted to the Robey wagon is, as previously stated, of the locomotive type. Its efficiency and economy are well known. These attributes are further increased_on the Robey by the fitting of the Belpaire type fire-box, which has better steaming properties because of the lack of bars on the firebox crown ; for this reason also it can be more readily cleaned.
The firedoor on the Robey boiler opens from the bottom, being hinged at the top; suitable baffles are arranged to prevent cold air, from impinging on the fire plates and tubes.
The water supply is, as usual, in duplicate, an injector and force pump being fitted. The latter has several novel and commendable features, It is chain driven from the engine shaft, reduction of gearing being in the proportion of 2i to 1. From the crankshaft an eccentric is fitted, but the drive from the eccentric, instead of being by a single rod coupled direct to the pump ram, is by a pair of rods, which are attached at their lower ends to a crosshead. The crdsshead is secured to the ram. This arrangement allows of the ram; itself being provided with additional support so that there is practically no tendency in the case of the Robey pump for the pump barrel to be worn oval. Another feature of the pump is the extreme ease of access. This will be gathered in part from our illustration. We may add, furthermore, that it is possible to remove all valves for grinding purposes, and to replace them, without disturbing any other part.
Engine: the High-pressure Gear, The engine is the normal side-byside compound type, the cylinders being ai ins, and 7 ins, diameter, stroke 7 ins. A special feature is the arrangement of the gear whereby both cylinders can temporarily be worked with highpressure steam. Here, again, we have the subject of a Robey patent, and we reproduce aspecial drawing illustrating this important point. • It will be noted that by the operation of one lever, high pressure steam is admitted and at the same time the normal connection between the high and low pressure cylinders is interrupted, and the exhaust from the high pressure cylinder released to the atmosphere. The drawing we reproduce is almost self-explanatory. It will be seen that pulling the vertical lever over to the right, which is towards the driver, opens the valve admitting steam to the low-pressure cylinder, and at the same time ._ draws the piston valve, near the bottom of the drawing, to the right, allowing of communication between the high pressure exhaust passage and the atmosphere. This piston valve is baIancedand has in addition to the steam-tight properties afforded by the rings an additional seating formed on its end, so that when closed there is practically no possibility of steam exhausting. .f rem the high-pressure cylinder .direct to atmosphere. It will be gathered that to work the engine as a high-pressure machine, the man must retain his hold upon the operating lever. As soon as he releases this lever, it drops back to the shut position, and the engine works, normally as a compound. This ensures to a great extent that misuse be not made of the highpressure gear. It is, of course, only provided for exceptional conditions of service.. Transmission: No Keys.
The transmission is by means of the usual steam-wagon type of two-speed gear, then by one long roller chain to the differential gear on the rear axle. .A special feature, of course, is that no keya are arranged for securing any of the driving elements. The double sliding component on the crankshaft is carried on a square. Both of thc large gears on the intermediate shaft have square holes formed in them, and these square holes fit on to corresponding bosses, one each side of the chain wheel, the three wheels then being gripped together by a suitably screwed sleeve and nut. The intermediate shaft, it will be observed, serves only as a bearing, and does not convey any of the driving torque. The drive to the rear axle by the differential gear is also through. squares. A scniare boss on the rear axle allows of a winding drum being fitted whenever one is required. The Rear Springing.
The rear springing of the Robey steam wagon is perhaps its most important feature. It formed the subject of much interesting comment and discussion when the wagon first appeared. Of its effectiveness in easing shocks to the wagon, we are able to write from personal experience : it is considerable. One does not ordinarily expect comfort in the course of a cross-country ride on a 5-ton steamer fully loaded. Yet that experience was ours upon a recent occasion, when we accompanied the designer, Mr. Leonard W. Jones on such a trip. The rear springs are attached to the axle by substantial axle boxes their ends are attached to vertical jaw-ended plungers; these again are supported on coil springs. Adequate means of lubrication are provided. The spring brackets likewise can be moved to and fro along the main frame. It is important to notice that these brackets are securedwithout any drilling of the frame, and vertical adjustment of the springs is. also possible by means of the screwed portions of the plungers to which the enda are attached.
Several special fittings can be supplied as extras. They are not included in the standard specification. A suitable case for totally enclosing the driving chain, an engine governor, a larger tank with a capacity for 200 gallons, and. a superheater are extras.
Economy: a Test.
The general economy of a steam wagon is well known. The following figures show the results of a recent test performed on a wagon under the supervision of the buyer The distance run was 19 miles, the wagon fully loaded, and. the average speed 7.6 m.p.h. ; 1 cwt. 3 qrs. of Welsh coal was used and 1.40 gallons of water, equivalent to 2.06 lb. coal and 14.75 lb. water per net ton-mile of load, The roads -were greasy, the weather mild, and rubber tireswere fitted.