A system for the movement of the hands of a clock or watch

Abstract: An analog type clock or watch having at least one hand and a scale of indicia showing time, comprising means for moving said at least one hand along a closed, non-circular path, having a first and a second straight section, parallel to each other and joined respectively at their ends by corresponding semicircular portions, so that the free end of said at least one hand travels along two straight sections and makes two 180 degree movements as it turns to indicate the time; said means comprising a motor element driven at a constant speed, said element being per se known, arranged so as to actuate a driven element to which the inner end of said hand is fixed; said driven element cooperating with guide means arranged to impart an alternately translatory and rotatory movement to said driven element, so that the free end of said hand follows said closed, non-circular route, pointing in succession to marks indicating the time arranged on the dial of said clock or watch.

Description: The present invention relates to a system which causes the hand of a clock or watch to perform a new and original movement differing essentially from that of conventional clocks and watches with so-called "analog" time display. As is known, in conventional clocks and watches of the analog type, the hands indicating the hours, the minutes and possibly the seconds move following a circular path, generally following a single scale of indicia on the dial of the clock itself. It is also known from DE-C-218.946 and FR-A-1.001.877, an analog type clock or watch having at least one hand and a scale of indicia showing time, comprising means for moving said at least one hand along a closed, non-circular path, having a first and a second straight section, parallel to each other and joined respectively at their ends by corresponding semicircular portions, so that the free end of said at least one hand travels along two straight sections and makes two 180 degree movements as it turns to indicate the time; said means comprising a motor element driven at a constant speed, said element being per se known, arranged so as to actuate a driven element to which the inner end of said hand is fixed; said driven element cooperating with guide means arranged to impart an alternately translatory and rotatory movement to said driven element, so that the free end of said hand follows said closed, non-circular route, pointing in succession to marks indicating the time arranged on the dial of said clock or watch. The aim of the present invention is to provide an improved mechanism for driving the at least one hand along a closed non-circular path, having the features detailed in the characterising clause of claim 1. The present invention will be better described below through the description of preferred embodiments thereof, given as a non-limiting example, and with reference to the enclosed figures, in which: figure 1 is a plan view of a clock dial; figure 2 is a perspective view of a mechanism for moving the hands of a clock or watch; figure 3 is a perspective view of a wrist watch; figures 4A and 4B, taken together, show an example of a mechanism for moving the hands of a clock or watch according to the invention; figure 5 shows a detail of the driving mechanism of figure 4A; figure 6 shows a sectional view taken along lines VI-VI of figure 5; figure 7 shows another detail of the driving mechanism of figure 4A; figure 8 shows another detail of the driving mechanism of figure 4A; and figure 9 shows a sectional view of the detail shown in figure 8. Reference is made to figure 1, in which is shown the dial 1 of a clock or watch, said dial comprising two distinct and separate scales set side by side, of which a first scale, generally indicated with 2, relating to the hours and marked in part with Roman numerals and the rest with respective dots, and a second scale, generally indicated with 3, relating to the minutes, with numbers, for example, marked every five minutes and the remaining minutes indicated by respective dots. The two scales 2 and 3 are externally bordered by respective outlines 4 and 5, having the same shape, made up of two straight, parallel, opposite sections, joined by two substantially semicircular sections, one at the top and one at the bottom. It must be specified that, although in dial 1 scales with indicia relating to hours and minutes have been given, it is also possible to provide on the dial itself, as well as the scales mentioned above, scale for seconds next to that for hours or that for minutes, or alternatively the scale for hours alone. Along the longitudinal axis line of each scale 2 and 3 a slot 6 and respectively 7 is made in the dial 1, said slot being of the same length as the straight sections of the outlines 4 and 5, each of said slots having a circular enlargement 10 in correspondence with both of the ends. In each of the slots 6, 7 a hand 8, 9 runs, connected to a respective mechanism which will be described below and which causes said hand to move in a linear manner along the respective one of said slots, so as to indicate on its upward stroke the hours and the minutes marked on the left hand straight section, respectively, as seen in figure 1, of the outlines 4, 5, while during its downward stroke it indicates the hours and the minutes marked on the right hand straight section of said outlines, respectively. When the hand 8, 9 reaches the upper or lower end of the respective slot 6, 7, said mechanism causes it to rotate in the relative circular enlargment 10, so as to indicate the hours marked on the substantially semicircular upper or lower section of the respective outline 4, 5. With reference to figure 2, a description will now be given of the mechanism mentioned above for the movement of each of the hands 8 and 9 with said linear and rotating movements. The mechanism mentioned above for the movement of each hand 8 and 9 comprises two rollers rotatingly fixed to the case of the clock in question, of which one is a driving roller, indicated with 11, having on its perimeter a series of equidistant pins of which only one is illustrated and indicated with 12, and the other a driven roller, indicated with 13. Between rollers 11 and 13 a flat circular belt 14 is positioned, along the longitudinal axis of which is made a sequence of holes 15, having a diameter slightly larger that that of the pins 12 on roller 11, placed at intervals equal to those between said pins, said holes 15 being suitable to be engaged by said pins 12 to cause the belt 14 to turn following rotation of the driving roller 11. On the outer side of the belt 14, perpendicularly to its upper and lower edges, a rod 16 is fixed, having a first section 17 bent into a right angle, the length of said first section being equal to the radius of the rollers 11 and 13. From the free extremity of said first section there extends, perpendicularly and integral to said first section, a second section 18, parallel to the axis of the rollers 11 and 13, and engaged in the slot 6, 7. On the free extremity of said second section 18, the hand 8, 9 is fixed. With the mechanism as above, the movement of the rod 16 carried by the straight sections of the belt 14 becomes the linear movement of the hand 8, 9 along the slot 6, 7, while when the rod 16 reaches the radius of the driven roller 13 perpendicular to the ascending section of said belt, or in correspondence with the edge of the radius of the driving roller 11 perpendicular to the descending section of said belt, which correspond, respectively, to the arrival of the hand 8, 9 at the upper or lower end of the slot 6, 7, said hand, as the movement of the belt 14 continues, respectively, around the driven roller 13 or around the driving roller 11, will make a turn, with the section 18 of the rod 16 turning in the upper or lower circular enlargement 10, in view of the fact that the length of section 17 of the rod 16 and the radius of the rollers 11 and 13 are equal, so that the section 18 of the rod 16, during the movement of belt 14 around the rollers 11 and 13, forms a continuation of the axis of one or the other roller. For rotation of the driving roller 11 it is possible to provide a toothed wheel (not shown) keyed to the shaft of said roller, suitable to engage with a pinion keyed to the central pin for rotation of the hands in a conventional clock, or alternatively it is possible to provide a stepper motor for said roller. In figure 3 is shown, in a perspective view, the arrangement of a wrist watch, with a dial like the one shown in figure 1 and with two mechanisms (not shown), for example of the type shown in figure 2, incorporated inside the case, one of said mechanisms driving the hour hand 8 and the other driving the minute hand 9. Now, with reference to figures 4A, 4B, 5, 6, 7, 8 another embodiment for driving the hands of a clock or watch will be disclosed. This embodiment is particularly suited for wrist-watches, even if not limited to these, because it makes a more efficient use of the very limited mechanical power available in a wrist-watch. Figures 4A, 4B taken together show the general arrangement of a dial 100 having two scales 101, 102 equivalent to the scales 2, 3, shown in figures 1 and 3 (for the sake of simplicity only the mechanism at the left of figures 4A, 4B will be disclosed). A hand 103 for indicating hours along the path or scale 102 is mounted on a half-wheel 104, the structure of which will be better disclosed hereinafter, having an internal toothing 105 meshing with a drive pinion 106 rotated in a conventional way as it is well known to a person skilled in the art. The half-wheel 104 is pivoted in 107 on a movable carriage 108 that moves along a straight path 109. The half-wheel 104 can perform either a rotational motion or a rectilinear motion according to whether the pinion 106 is meshing with the semicircular toothing 105a or with the straight toothing 105b. When the pinion 106 engages the toothing 105a, the free end of the hand 103 follows the semicircular path at the top or bottom of the scale 101, while when the pinion 106 engages the toothing 105b, the free end of the hand 103 follows the straight part of the scale 101. In order that the half-wheel 104 follows the intended motion, several mechanical constraints are provided as follows: for maintaining the correct engagement with the pinion 106, the latter is provided with a retaining pin 109' that runs along a groove 110' present in the wheel 104. As can be more clearly seen in figures 5 and 6, the toothing 111 of the pinion 106 meshes with the internal toothing 112 of the half-wheel 104. With the cooperation of the toothings 111, 112, and the pin/groove arrangement 109'/110' a continuous engagement of the wheel 104 with the pinion 106 will be maintained. This sole constraint, however, will not be sufficient for guiding the wheel 104. In order to assure the complete motion of the wheel 104, there is provided an arrangement comprising two pairs of guides 113, 114 and 115, 116, respectively that define between them a groove where a pin 117 can ride (see figure 7 for more details). When the wheel 104 moves clockwise as shown by the arrow 118, at a given moment (i. e. at the end of the circular motion of the wheel 104) the pin 107 will engage the part 114a of the guide 114; at the same time, the pinion 106 will engage the rectilinear toothing 105b of the wheel 104, so that the wheel 104 (and the hand 103) will start a motion upwards as is shown by the arrow 119. The same state of affairs will occur at the engagement by guide pin 117 of the guides 115, 116 when the wheel 104 from its topmost position will start to descent with the free end of the hand 103 following the right part of the path 101. The wheel 104 is rotatably arranged, as mentioned above, on a sliding carriage 108. A pin 120 fostened to the wheel 104 passes through the carriage 108 and carries a hand 121 (103). This is better shown in figures 8 and 9, where an enlarged representation of this structure is shown. The operation of the mechanism thus disclosed should be clear. In the situation shown in fugre 4A, the carriage 108 is temporarily standing in the position shown, while the wheel 104 rotates through 180° in a clockwise direction, carrying with it the hand 103 (121). When the toothing 105b becomes parallel to the path 109, the carriage 108 will slide along the path 109 rising towards the top of the drawing of figures 4A, 4B, carrying the hand 103 (121) along a rectilinear path. The converse occurs when the carriage 108 has reached its topmost position, where the wheel 104 will have its toothing 105a engaged by the pinion 106 performing thus a rotation through 180°. The cycle will repeat itself for the operation of a clock or watch.

Claims: An analog type clock or watch having at least one hand (103,121) and a scale (101,102) of indicia showing time, comprising means for moving said at least one hand along a closed, non-circular path, having a first and a second straight section (109), parallel to each other and joined respectively at their ends by corresponding semicircular portions, so that the free end of said at least one hand travels along two straight sections and makes two 180 degree movements as it turns to indicate the time; said means comprising a motor element (106) driven at a constant speed, arranged so as to actuate a driven element (104) to which the inner end of said hand (103,121) is fixed; said driven element cooperating with guide means arranged to impart an alternately translatory and rotatory movement to said driven element, so that the free end of said hand follows said closed, non-circular path, pointing in succession to marks indicating the time arranged on the dial of said clock or watch, characterized in that said means for moving said hand (103,121) along a straight section (109) and for turning said hand when it reaches the end of said straight section (109) comprise a half-wheel (104) having a toothing (105) meshing with a drive pinion (106), said half-wheel (104) being journalled on a journal carried by a sliding carriage (108) movable along said straight section (109); said half-wheel also carrying a pin (120) supporting said hand (103,121); the arrangement being such that when said half-wheel (104) meshes with said drive pinion (106) along a semicircular part (105a) of said toothing (105), the hand (103,121) performs a half-turn motion, while when said half-wheel (104) meshes with said drive pinion (106) along a rectilinear part (105b) of said toothing (105), the hand (103,121) runs along the straight section (109). An analog type clock or watch, according to claim 1, comprising an additional means for driving a second hand along a closed path similar to said means for moving said first named hand.

Inventors: FERRARA CARLO, FERRARA, CARLO
Applicants: FERRARA CARLO, FERRARA, CARLO
Application year: 1992
Main classification: G04B19
IPC codes: G04B19, G04G9, G04C3