From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Technical description and operating instructions for the Douglas adjustable-for-reach steering wheel.
| Identifier | ExFiles\Box 154\3\ scan0225 | |
| Date | 1st January 1933 guessed | |
| Foreword CONSIDERING the extent to which the driver's comfort has been studied during the advance in motoring design of late years, it is rather remarkable that beyond the universal adoption of the sliding seat, little has been done to deal with the problem of so arranging the relative positions of the driver and the steering wheel. The sliding seat was, undoubtedly, a great advance, but so long as human beings vary in stature and have their own personal ideas and preferences for driving position, a sliding seat and FIXED steering wheel can be only a compromise. When this seat is set comfortably for leg and car pedal reach, except for a fortunate few, the FIXED steering wheel position will be found to be either too close or too far away; obviously, the PERFECT combination is the sliding seat AND the "DOUGLAS ADJUSTABLE-FOR-REACH STEERING WHEEL," and this ideal combination is now available. Action of Wheel Referring to the line drawing on preceding page, it will be seen immediately that the principle of the wheel is extremely simple, being that of moving the entire wheel and its hub 'A' up or down the extended column 'B' of steering gear; both bore of hub 'A' and column 'B' are suitably machined with longitudinal splines or serrations 'C', engaging each other, so that while up and down movement is possible, no relative rotational movement between hub and column can take place. It only remains to provide means for quickly and easily clamping the hub 'A' at any selected position within the total range of longitudinal movement, so that such position is suitable to the particular driver in conjunction with similar to-or-fro adjustment of the sliding seat. This clamping is effected very simply and efficiently by saw-cutting the hub on one side at 'D' and providing a clamping bolt 'E' across the saw-cut; the hardened cam 'F' formed on one end of the operating lever 'G' bears against the hardened washer 'I', thus when the lever 'G' is closed by the driver to the position encircling the hub 'A' as shown on drawing, due to the cam 'F'; the hub is closed in somewhat and a powerful pinching action occurs, due to the cam 'F'; a secure grip is obtained on the splines or serrations machined on column 'B'. It should be noted that absolute safety is secured; even if the clamp is left open, the car can still be steered safely. In fact, it is perfectly safe to drive with the clamp open. All that can happen will be that the wheel will slide up or down to its full extent of 3", if the driver pulls or pushes it; the steering will be unaffected. The degree of grip preventing unwanted longitudinal movement can be immediately adjusted as required, by screwing up or unscrewing, by the fingers, the knurled nut 'H' on other end of bolt 'E'. This must, of course, be done with the lever 'G' in its open position. It should be noted that this adjustment of nut 'H' is only provided to obtain the correct amount of grip when the wheel is assembled; once set, this grip remains constant and needs no further attention, except at very long intervals, in order to take up any slight wear that may have occurred between cam and washer, so restoring the correct grip. It will be readily seen that when lever 'G' is closed, it lies neatly round the hub 'A', is unobtrusive and cannot be accidentally opened by catching in the driver's clothing, etc. At the same time, since the amount of force required to close or open it is comparatively small, this can be done easily to effect any required change in wheel position. It is obvious that in all except the lowest position, the splined column 'B' would become exposed below the hub 'A'; a neat plated dust-cover 'J' is, therefore, provided, in the form of a volute spring. One end (the upper) is taken by a suitable cup or actually in a recess in the bottom of hub 'A', as shown; the other end (the lower) is taken on a suitable abutment or washer on column 'B'. In the lowest position of wheel, this dust-cover 'J' is completely telescoped into itself as shown; as the wheel is raised, 'J' extends owing to its spring effect, thus a neat outside appearance is always obtained, whatever the wheel position may be. Controls Where central controls are used on top of wheel, these must obviously rise or fall with the wheel. This is accomplished by securing these controls to a special type of bushing 'M', which is itself secured inside wheel hub by the two screws 'O'; this bushing has oil-soaked felt bearings 'L', which prevent any possibility of rattle or wear, yet permit the wheel to rotate as when steering the car, without rotating the controls. At the same time, when any up or down adjustment is effected to wheel, this bushing 'M' compels the central controls to rise or fall with the wheel. Since the ends of the central controls at bottom of steering gear box are fitted longitudinally, it becomes necessary to provide for the up or down movement of their upper ends. This is accomplished very simply by providing telescopic joints in each control tube, about half-way down column 'B'; these joints, naturally, do not need any clamping arrangement, and are a simple form of "scarfed" joint, giving the necessary movement of 3", without backlash or rattle, etc. Details are not shown in this brochure, as these controls do not form part of the Adjustable Wheel as such and they depend largely on the exact type of controls used by any particular motor-car manufacturer. For example, where a horn button and perhaps dimmer switch only are in use on top of steering wheel, the matter is very simple; the wires for these controls pass down the column 'B' and simply rise or fall with the wheel, no additional mechanism being necessary. Steering Gear It will be noted that the Adjustable Wheel cannot be applied directly to any existing steering gear, but the modifications necessary to the steering gear are confined to the top end of column 'B'. This part, where the ordinary fixed wheel is normally secured, is made about 3 1/2" longer, has the splines or serrations 'C' machined on it, also the detent groove 'P' for receiving the Circlip 'Q'; the object of this spring circlip 'Q' is to prevent the wheel being accidentally pulled right off column at any time. The safety diameter 'R' in hub 'A' is provided so that circlip 'Q' cannot spring open and come out of its groove, however hard the wheel is pulled when in its top adjustment position. General When effecting an adjustment to wheel position, unclose lever 'G' fully and push or pull the wheel to position desired, taking care to apply approximately equal force to either side of wheel rim; one-sided effort may cause wheel to stick. Re-close lever 'G' by placing fingers round wheel hub and applying pressure on lever 'G' with the heel of palm of hand—the knack of this is easily acquired. This adjustment can be carried out easily, if desired, with the car moving, but in the interests of road safety, it is strongly recommended that it be done only with car standing, when both hands can be used, if necessary. The grip on column 'B' is correct when lever 'G' can be just closed by one hand, as above described. It is important that the lever should be FULLY closed, so as to lie closely round wheel hub. If, after closing as described, it is possible to move wheel at all by exerting heavy push or pull on the rim, the grip is insufficient. Open lever 'G' and screw up (R.{Sir Henry Royce} H.{Arthur M. Hanbury - Head Complaints} Thread) the nut 'H' A VERY LITTLE; a movement of about 1/64" at the rim of nut 'H' should be enough. Close lever and again test wheel; repeat until wheel remains firm against hard pushing or pulling at rim. The grip adjustment will then remain set for an indefinite period. Occasionally put wheel in highest position, push dust-cover 'J' upwards or downwards away from column or hub and put a few drops of engine oil on the splines on column; a spot of oil now and again on the washer 'I', where the cam 'F' bears against it will assist easy action of the clamp. | ||