GB2237909A

GB2237909A - Alignment of totaliser display drums

Info

Publication number: GB2237909A
Application number: GB9022001A
Authority: GB
Inventors: Bruno Ortelli
Original assignee: Veglia Borletti SRL
Current assignee: Veglia Borletti SRL
Priority date: 1989-10-20
Filing date: 1990-10-10
Publication date: 1991-05-15
Anticipated expiration: 2010-10-10
Also published as: PL164898B1; DE4033134A1; IT221659Z2; IT8953421V0; FR2653580A1; GB9022001D0; AR243697A1; FR2653580B1; IT8953421U1; TR27619A; GB2237909B; MX172885B; PL287387A1

Abstract

A totaliser comprises a series of coaxial numeral drums (18) associated with a series of carry forward pinions (26). To align the drums in a display window there is provided a single leaf spring (36) cooperating with a prismatic cam (33) fixed for rotation with one of the pinions (26). This pin ion can be associated with the highest order of the totaliser or else an intermediate order. <IMAGE>

Description

1 r A DEVICE FOR ALIGNMENT OF THE NUMBERS OF A TOTALISER NUMBERING MACHINE

HAVING NUMERAL DISPLAY DRUMS The present invention relates to a device for aligning the numbers of a totaliser numbering machine having a number drum display, for example for motor vehicle odometers (mileometer).

Totaliser numbering machines of the said type comprises a series of coaxial numeral drums each associated with an order of numerical magnitude: units, tens, etc. As is known, these drums are disposed in correspondence with a window which allows one number to be displayed at a time, and are in engagement with a series of pinions for carrying forward the tens from one order of magnitude to the next, to function as totalisers. For brevity hereinafter, these will be called totalisers.

Because of the inevitable play in the engagement between the drums and the pinions, after one carry forward operation the drum which has been subjected to the carry forward movement is displaced by a certain angle with respect to the drum which has caused it. In the case of plurality of simultaneous carry forward movements, for example to pass from the number 99999 to the next, the drum of the highest order is misaligned with respect to that of the first order by the sum of the individual misalignment angles, which can cause the user to make an error in reading the totaliser.

There have already been proposed totalisers provided with an alignment device for the various number drums. In one known totaliser, each drum has associated with it a spring positioner which makes the associated drum always assume a position aligned on the number to be displayed. This totaliser has the disadvantage that each spring requires a supplementary couple to make the drum rotate from one position to the next. Therefore, on the one hand this supplementary couple is required too frequently, and on the other hand when two or more drums effect simultaneous carry forward movements this couple becomes excessive so that the action of the totaliser is subject to jamming.

It has also been proposed to provide each carry forward pinion with a face cam having a V-section portion in correspondence with each number. This cam is engaged by a complementary cam carried by the adjacent pinion, whilst a compression spring holds the various cams constantly in engagement. This spring must be rather robust to constrain the drums to an alignment position even when there is a series of simultaneous carry forward movements.

This totaliser has the disadvantage of being very complicated and also requires a certain torque for each carry forward movement. Moreover, in the case of a i 1 i i 1 plurality of simultaneous carry forward movements, this couple is multiplied by the number of drums to be turned.

The object of the invention is that of creating a totaliser which eliminates the above-listed disadvantages of known numbering machines, and will be of the maximum simplicity and security in operation.

This object is achieved by the totaliser according to the invention, which comprises a series of coaxial number drums, each associated with a numerical order of magnitude and provided with numbers from "0" to "9", adapted to be seen through a window, and a corresponding series of pinions in engagement with the said drums for carrying forward the tens, and is characterised by the fact that at least one positioner is adapted to act on the drum or on the pinion associated with the drum of a predetermined numerical order to hold the corresponding drum in alignment in the said window, the number of the said positioners being very much less than that of the said orders.

For a better understanding of the characteristics of the invention a preferred embodiment is now described, by way of example, with the aid of the attached drawings, in which:

Figure 1 is an exploded perspective view of a 4 totaliser including a device for alignment of the numbers according to the invention; Figure 2 is a section through the totaliser taken on the line II-II of Figure 1; Figure 3 is a diagram of a totaliser without any type of alignment device; Figure 4 is a diagram of a totaliser provided with a known alignment device; Figures 5 and 6 are two diagrams of two totalisers provided with alignment devices formed as two variants of the invention.

With reference to Figure 1, the reference numeral 10 generally indicates a support frame for the totaliser of a measuring instrument, for example an odometer for a motor vehicle. The support 10 is made of plastics material and comprises two sides 11 and 12 integral with a pair of cross members 13 and 14. Each side 11, 12 is provided with a seat 16 in which a spindle 17 is fitted.

The totaliser comprises a series of coaxial number drums 18, each associated with one numerical order of magnitude: units. tens. hundreds etc. In Figure 1 there are indicated six drums 18 so that the totaliser has a capacity up to 999,999. The drums 18 are rotatable with light friction on a spindle 19 housed in a seat 21 provided in the two sides 11 and 12. Each drum 18 carries 1, on its outer surface 22 the numbers from "0" to "T', which are displayed through the usual window of the instrument, not shown in Figure 1 and indicated 23 in the diagrams of Figures 3 to 6.

Each drum 18 (Figure 1) has on the side facing the lower order, that is towards the left, a toothed ring 24, whilst on the opposite side it has a pair of teeth for driving the tens, not visible in the drawings. The toothed ring 24 engages with a corresponding pinion 26 to carry forward the tens. The various pinions 26 are rotatable on another spindle 27 housed in another seat 28 of each of the two sides 11 and 12. In the embodiment of Figure 1, the toothed ring 24 has twenty teeth, whilst the pinion 26 in relation to its smaller diameter with respect to that of the ring 24, has eight teeth.

The teeth of each pinion 26 are alternately of two different widths: the teeth 29 have a limited width and are adapted to engage only with the toothed ring 24 of the associated drum 18, the teeth 30 have a greater width and are adapted to engage both with the toothed ring 24 of the same drum 18 and with the carry forward teeth of the drum 18 to the right.

The carry forward teeth are disposed on each drum 18 in an angular position such as to engage a tooth 30 of the pinion 26 when the display in the window 23 passes from the number "T' to the "0". The teeth 30 of the first pinion 26 to the right are engaged by two carry forward teeth carried by an unnumbered drum 31. This is disposed to the right of the edge of the display window 23 so that it constitutes a blind drum. Fixed for rotation with it is a helical gear wheel 32 in mesh with a worm screw which is made to rotate with a continuous motion during the movement of the motor vehicle, in a manner known per se.

When the drum 31 has completed one revolution its carry forward teeth cause the first pinion 26 to turn through an angle equal to two teeth. This pinion 26 draws with it the unit drum 18, which turns by one step, that is to say by two teeth. Similarly, when one of the drums 18 has completed one revolution. its carry forward teeth cause the pinion 26 to its left to rotate thus effecting the associated carry forward of the tens.

Obviously the last drum 18 on the left does not drive any carry forward so that when all the drums 18 are in the "9" position and the unity drum drives a carry forward, this is transmitted in a chain through all the drums 18 successively, which will now each show 1101' in the window 25 23.

Because of the inevitable play between the carry forward teeth of a drum 18 and the teeth of the pinion 26, and between these and the teeth of the ring 24 of the successive drum 18, in the passage of a drum 18 from "9" to "0" the next drum 18 remains misaligned by a quantity "s" (Figure 1). If there is a chain of carry forward movements on two or more drums 18 starting from that of the unit drum, the last drum 18 involved in the carry forward remains misaligned by a quantity equal to "ns", where n is the number of drums 18 involved. To allow reading of the numbers of all the drums 18 the window 23 must therefore have a height M which exceeds the height of the numbers by a quantity nxs, thus leaving the numbers adjacent to that which it is desired to display slightly in view so that reading the display is irksome.

For the purpose of aligning the drums 18 each time, it is normal to provide, integral with each pinion 26, a prismatic positioning cam 33 (Figures 1 and 2). In the illustrated example the cam 33 has a square section, that is to say having four positioning faces 34 (Figure 2) each disposed in correspondence with a tooth 30 and joined together by a small bevel 35. Therefore the positions defined by the faces 34 of the pinion 26 are one every two teeth, so that the positions of the corresponding drum 18 are also one every two teeth, and therefore ten.

In a known alignment device, a positioning spring 36 (Figure 4) acts on each cam 33. When the pinion 26 turns through one step the spring 33 acting on the face 34 (Figure 2) generates a certain resistance until the cam 33 passes one half of a step. After this position the spring 5 36 acts on the next face 34 and tends to make the pinion 26 complete the step so that the associated drum 18 is aligned in its next position. In this device the height of the window 23 (Figure 4) can therefore be reduced to n, that is to say to the height of one number of the drum 18.

However, in the case of a chain of carry forward movements on several drums 18, the couple required to overcome all the springs 36 involved is very high.

According to the invention, the totaliser is provided with a number of positioners significantly less than the number of drums 18 in the numbering machine. In particular. the totaliser of Figure 1 is provided with the single positioner 36, constituted by a leaf spring adapted to act on the cam 33 of a single drum 18. For constructional simplicity all the pinions 26 can be provided with cams 33. This leaf spring 36 can be formed by an elastic metal tongue 38 having one end 39 folded in a U-shape. The end 39 is inserted in a seat 40 (Figure 2) of the frame 10 in such a way that its free edge 41 hooks against a shoulder 42.

According to a first variant of the invention, represented 1 j! i i i 4 1 in the diagram of Figure 5, the leaf spring 36 is disposed in correspondence with the pinion 26 of the highest order. Since the position of this pinion 26 is now always aligned, the maximum misalignment of each of the various drums 18 between the first on the right and the last on the left first increases and then decreases according to the variation shown in Figure 5, so that the maximum obtainable misalignment is equal to 3s and the height h of the window 23 can be less than that of Figure 3.

In another variant, represented in the diagram of Figure 6, the leaf spring 36 is disposed in correspondence with an intermediate pinion 26, for example the fourth from the right. In this case the misalignment of the various drums 18 first increases, then decreases between the first and the fourth drum 18, so as to then increase up to the sixth drum 18, as indicated in Figure 6, so that the maximum overall misalignment is equal to 3s.

In both of the said variants the torque required to overcome the action of the single spring 36 is very low and is exerted only when the corresponding pinion 26 is turned. Therefore, in the case of Figure 5 this occurs every 100,000 kilometres, in the case of Figure 6 this 25 occurs every 1, 000 kilometres.

From what is seen above it is evident that, by arranging a k single positioning spring 36, at the cost of a slight misalignment of the drums 18, which does not disturb the display, not only is the torque necessary to effect the carry forward of the orders in which the spring 36 is disposed is reduced, but also the frequency of this is reduced. Moreover, manufacture is much simplified and therefore the cost of the totaliser is also reduced.

1 It is intended that the alignment device described can have modifications and improvements introduced thereto without departing from the scope of protection. For example, it can be adapted for a totaliser with internal rather than external carry forward pinions. Moreoveri the prismatic cam can be provided integrally with each drum 18, in which case it will have ten faces rather than four.

a

Claims

An alignment device for the numbers of a totaliser numbering machine having numeral display drums, comprising a series of coaxial numeral drums each associated with one numerical order of magnitude and provided with numbers from '1011 to "W' adapted to be displayed through a window, and a corresponding series of pinions in mesh with the said drums for carrying forward the tens, characterised by the fact that at least one positioner (36) is adapted to act on the drum (18) or on the pinion (26) associated with a predetermined order to hold the corresponding drum (18) in alignment in the said window (23), the number of the said positioners being very much less than that of the said orders.
2. A device according to Claim 1, characterised by the fact that a single positioner is provided comprising a leaf spring (36) in engagement with a prismatic positioner cam (33), each angular position of the said drum (18) being defined by one face (34) of the said cam.
3. A device according to Claim 2, characterised by the 0 fact that the said cam (33) is fixed for rotation with the corresponding pinion (26) of the said series, the said leaf spring (36) including a U-shape portion (39) resiliently inserted into a fixed seat (40).

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4. A device according to Claim 2 or Claim 3, characterised by the fact that the said leaf spring (36) is disposed in correspondence with the drum (18) of the 5 highest order (Figure 5).
5. A device according to Claim 2 or Claim 3, characterised by the fact that the said leaf spring (36) is disposed in correspondence with the drum (18) of an 10 Intermediate order.
6. A device for alignment of the numbers of a totaliser numbering machine having numeral display drums, substantially as described with reference to the 15 attached drawings.

P4d 1991 4901The P OMM State Houm 06171 H -rn. ln WC1R41P. Furthercopies; rnay be obtained from R 1 Urdt C bUle P Cwnbk. Cross Kem =t NPI 7HZ. Printed by Multiplex techniques lid. St Mary Cray. Kent.