Chapter XII: Keyless Winding
126. This accessory of the modern watch is now very much desired and, it must be granted, so useful and pleasant that it has acquired much general favour; even though considerable sections of the public still distrust it, particularly in England where many respectable watchmakers do not yet endorse watches with pendant winding. However, it is important to say something about its construction and finishing.
Pendant winding is more than a plaything or a convenience for the owner; it is useful in many ways. Firstly it offers the possibility of winding a watch and setting the hands at any time and in any place, because these operations do not require opening the case. Winding or setting with an ordinary watch must be carried out when the watch is held still, and therefore cannot be done in a carriage or on horseback or while walking. Likewise we can only attempt this when we are under a roof and in a place which is free of dust, whereas we can adjust a watch with pendant winding in the open air without being afraid of rain or dust. All this is more than a mere convenience, because it ensures continuing operation during a journey, when the owner rarely finds a quiet moment to wind his watch or has forgotten to bring its key; it is generally recognized that a watch is of double importance to the traveller.
127. Yet another benefit can be expected from keyless winding and I would regard this as an important advantage as well. The turning movement, which is necessary for winding up a keyless watch, takes place perpendicularly or at right-angles to the balance. This offers complete protection against the harmful effects of the bad, but very frequent habit of watch owners who move the watch as well as the key when winding. It is easy to see that this habit results in a fast circular movement of the watch level with the balance, and it is repeated 10-12 times until the winding is finished. If, in the best case, this casual treatment does not damage the escapement, then it at least causes deviations in rate by violent over-banking; this irregularity, for which it is difficult to find an explanation, lowers a watch in the opinion of its owner, who often attributes it to a lack of skill or care by the repairer to whom the watch was entrusted.
128. A very important consideration with pendant winding is the greater durability of the case and the better protection from damage and destruction. In a watch with key winding, repeated opening of the case wears out the rim and hinge and additionally, it is necessary to have a case that does not close too tightly. This is not the situation with a pendant wound watch whose case can close better and provide far more protection against dust entering.
129. The necessity to open the case of a key wound watch at least once a day permits the direct entrance of dust. The key is also a very eager mediator for the introduction of fibres and impurities of all kinds, particularly with the bad habit of carrying the key in a vest pocket which nobody thinks to clean.
130. In order to understand and compare the different keyless mechanisms it will be necessary to group them; otherwise the great diversity of designs could not be conveniently considered.
Nearly all keyless watches can be divided into two main classes.
1. Those where hand setting is done via adjustable parts on the stem.
2. Those where this is done by means of a rocking bar.
131. The last mentioned class, which must be used for fusee watches, is delicate and requires very careful execution. For this reason the first type is more common, particularly in Swiss watches. If we examine this class of keyless mechanism then we can easily subdivide it by differentiating between those which set hands by pulling the crown out, and those which have a pusher to engage hand-setting.
132. In most cases the latter kind uses what is known as Breguet clickwork; if the crown is turned to the right the mainspring is wound and if the crown is turned the other way nothing happens. This has the advantage that an awkward attempt to turn the crown in the wrong direction cannot damage the mechanism. Breguet clickwork is, however, not an essential part of this kind of keyless mechanism.
133. In most keyless watches the crown is connected (by a square or other fitting) to a stem which goes through the pendant to the winding pinion within the case body. In this arrangement the barrel arbor stands perpendicularly to the pinion and these two parts must be connected by a bevel gear. In most keyless watches this gear consists of a straight pinion and a straight crown wheel. However these give very imperfect power transmission because the teeth of the crown wheel, which are cut towards the centre, can coincide with the direction of the pinion leaf only at that point in the action where the side of the tooth is located on the line of centres. During the part of the action which takes place before and after the line of centres, the pinion leaf works against the outside or inside corner of the tooth, which is certainly of no benefit for either gear. With a pinion of small leaf number, the destructive effect of this type of gearing is considerable because the leaves work at a greater angle. Anyhow, the teeth of the straight crown wheel must be tapered from the outside and inside in order to minimise this fault.
134. For these reasons a conical gear is preferred and it offers the best conditions for a regular and gentle transmission of power and for durability. Besides, a conical pinion can be made much stronger than a straight one. It is actually very difficult to construct a conical wheel and pinion with theoretically correct tooth profiles; however, when they are made in the usual way they are completely satisfactory for what they are intended to do and have considerable advantages over straight pinions.
135. One of the best keyless mechanisms, because of its simplicity and durability, is the following: The barrel arbor (Fig. 37) has the usual square at its upper end and on this is fitted a large wheel, as big as the size of the upper plate allows, or, what is approximately the same, almost as big as the barrel. This wheel meshes with another wheel which is about 2/3 of the diameter of the first and which is concentrically joined to a conical wheel underneath the upper plate. The latter wheel is set in motion by a conical pinion whose arbor goes through the case pendant and carries a milled crown outside the pendant. At the same time, one of the two flat wheels on the upper plate serves as a ratchet by means of a suitable click with a spring. These are the fundamentals of the oldest watches with keyless winding, but since then many improvements have been made.
136. For the purpose of hand setting the most diverse mechanisms can be added. The oldest of these is the following: The stem (Fig. 38) can move along its length and, if the crown is pulled out a little, the winding pinion moves out of mesh with the conical or crown wheel and a lever pushes a small crown wheel on the stem into gear with the minute wheel, or a wheel connected to it. The small crown wheel is mounted by a pipe onto the internal end of the stem, which is either squared or left round but with its sides flattened for approximately 1/4 of their thickness. In the latter case the pipe has a fixing pin which is screwed into it sideways, so that it protrudes a little internally and thus has a sufficient grip on the flattened side of the stem to prevent the wheel rotating but still allows it to slide along the arbor (Fig. 38 shows the position of the parts when the crown is pulled out).
137. Another method is the following: A small pinion is fitted on the round part of the stem, on which it turns freely. The minute wheel meshes into a similar wheel of steel, which is provided with crown teeth, and these teeth are constantly in mesh with the small pinion on the stem, so that these two parts rotate with the motion work while the watch is running. The small pinion, which is held in place by a bridge, has a short pipe projecting towards the base of the stem which is cross-cut at its end so that four small recesses are formed, deep and wide enough to accept a pin which fits in a hole drilled through the stem. When the crown is pulled out, together with the winding pinion, the motion work pinion is activated by the pin fitting into one of the cross-cuts. If the crown is pushed back into its earlier position the motion work is disengaged and the winding pinion engaged again, as before.
138. This kind of hand setting is certainly very simple and reliable, but it is criticised because the crown, after being pulled out to adjust the hands, is often left in that position by careless people and the watch often stops; because the winding mechanism operates with considerable friction and the watch is unable to cope with this additional task. This problem substantially contributed to the distrust which developed against pendant wound watches; and eventually the designs where the crown is pulled out to adjust the hands were completely discarded.
139. Another arrangement of hand setting was better designed, and we can probably say that it fulfils the function completely. The winding parts are exactly the same except that that the winding pinion sits loosely on a round arbor whose end, extending beyond the winding pinion, is squared. On this square a small steel tube with a square hole is fitted, free enough to move easily on the square. The front face of the winding pinion and the appropriate face of this pipe are cut with ratchet teeth which fit exactly into one another. A spring, which operates in a groove cut in the pipe, holds both parts together so that the winding pinion rotates with the stem.
140. When it is necessary to set the hands, a small button or pusher (protruding from the case near the pendant) is pressed and this causes the pipe to slide inward on the square by means of the spring mentioned above. The internal face of the pipe has fine crown teeth which come into mesh with the minute wheel or another small wheel connected to it. At the same time the ratchet teeth of the pipe go out of mesh with those of the winding pinion so it no longer rotates with the stem. When hand setting is finished the button, if we do not continue pressing on it, lets the spring return and the pipe moves into its previous position, ready for winding.
141. An advantage of this arrangement is that if someone should turn the crown in the wrong direction damage to the winding parts and clickwork is prevented; because in this case the two ratchet wheels have the effect of Breguet clickwork.
142. Nevertheless, objections were raised against this system, because the opening in the band for the button was regarded as a opportunity for dust and so on to enter the movement, and because the projecting button could be pressed in accidentally while the watch was carried in a pocket. For these reasons much effort and thought were put into finding other methods for hand setting.
143. One method is a rather complicated arrangement of the case bow, which engages the motion work when the bow is turned down. The advantage which we may expect from this invention is very dubious, because the bow can be pushed down by accident when carrying the watch, which naturally brings it to a stop. Besides, many people have the praise-worthy habit of always turning down the bow when they put their watch flat on a table, in order to avoid scratching the polish or engraving. This would naturally have the same consequences.
The simplest and safest arrangement for hand setting, which is now generally used, omits the button and has a small pipe extending from at the edge of case which surrounds the pusher pin; this pipe has a cross-cut wide enough for the thumb nail of the left hand to push in the pin while the right hand turns the crown to set the hands.
144. Other mechanisms were devised for keyless hunter watches where the pusher protrudes from under the bezel but is inside the hunter cover of the case. This pusher, when pressed in, shifts part of its spring to the outside edge of the bezel where it is held securely, and the motion work is engaged with the stem and remains so from then on. The position of the spring and pusher is released when the case is closed and each part goes back to its earlier place. This arrangement is in every respect of great utility, but if the hands are set without closing the case afterwards, as some people do when they come home or go to bed, then the watch will stop.
145. From the preceding discussion we can arrive at some conclusions about the mechanism of hand setting, and I am of the opinion that these parts should always be designed so that they are based the following criteria:
1) It must not be possible to engage the motion work accidentally; on the contrary, it must be designed in such a way that the owner has to make a decided act of will to engage the motion work.
2) After hand setting, the mechanism must go out of mesh with the minute wheel without requiring any action by the owner.
These two principles are of extreme importance for the good and reliable operation of a watch, because a watch inevitably stops if the winding mechanism engages or remains engaged with the motion work at the wrong time. Any design which requires even a very small amount of care, which not all watch owners use with their watches, must be regarded as defective, so long as we can create other mechanisms which do not have these errors.
146. The kind of hand setting where the motion work is engaged by turning down the bow offends against both of these principles. Those mechanisms which require pulling the crown out and those by which the pusher is held fast until the case is closed commit errors against the second of the rules above.
147. There is an arrangement which is completely free of these faults, and it can be used for both open-face and hunter watches. With this the pusher protrudes from under the bezel and is flush with the outside of the case. The thickness of the pusher, approximately 1 mm or a little more, permits it to be pressed in by a nail without difficulty. The bezel of an open face case or the front cover of a hunter case must be filed through so that the end of the pusher just fits into it.
It is apparent that there is no opening for the entrance of dust, no pressure can affect the pusher from the outside, and that the original free position of the hand setting mechanism will be instantly restored by the pusher spring as soon as hand adjustment is completed. The only inconvenience of this method is that an open face watch of this kind requires the bezel to be opened to adjust the hands, which is not necessary with a projecting pusher. However, hand setting occurs only occasionally with a well adjusted watch, and it is a small inconvenience of no great importance on such rare occasions.
148. The other main group of winding mechanisms, those with a rocking bar, also deserve to be discussed. They offer several very important advantages, particularly for fusee watches in which the fusee arbor is always rotating and requires (like the barrel (15) of a watch with a going barrel) absolute independence from the winding mechanism at all times other than at the instant of winding up. Therefore, with a fusee watch the wheels must be on a rocking bar which is held in a neutral position by a spring, so that they affect neither the fusee wheel nor the minute wheel.
149. Most of these winding mechanisms have three wheels on the rocking bar, the centre one incorporating the conical wheel which meshes with the winding pinion. The stem does not have to extend into the movement and in many watches the whole of it is in the pendant. However this is not acceptable, and the magnitude of the lateral pressure produced by bevel gears emphasises the necessity of providing the internal end of the stem with a support on the edge of the pillar plate, which can be done very easily. A stem supported in this way allows the bevel gear to be examined with the movement out of its case, a convenience which is useful. The rocking bar is fastened so that its centre of rotation is also the centre of the conical wheel, for then the wheels on both sides remain in mesh with it whatever the position of the bridge. One of these wheels is constantly in gear with the barrel wheel, which sits on the square of the barrel arbor and transmits the winding movement. The other wheel stands sufficiently far away from the teeth of the minute wheel so that it does not mesh with them unless the wheel on the other side of the bridge is shifted completely out of mesh with the barrel arbor wheel. The rocking bar is held at this distance from the minute wheel by a spring.
150. For hand setting the position of the rocking bar must be reversed by pressure on a pusher. For this procedure see the remarks made in Art. 142-147. The pusher changes the position of the bar and puts the other wheel on this bar into mesh with the minute wheel while a stop pin, when it is necessary for a safe depth, prevents further movement. After the hands are set the spring moves the bridge back into its previous position.
15 Grossmann actually wrote "like the barrel arbor". [Trans]