GB2263552A

GB2263552A - An electronic bathroom scale

Info

Publication number: GB2263552A
Application number: GB9300751A
Authority: GB
Inventors: Hans-Dieter Poweleit
Original assignee: Robert Krups GmbH and Co KG
Current assignee: Robert Krups GmbH and Co KG
Priority date: 1992-01-17
Filing date: 1993-01-15
Publication date: 1993-07-28
Anticipated expiration: 2013-01-15
Also published as: HK44795A; GB2263552B; FR2686416B1; FR2686416A1; GB9300751D0; DE4300950A1

Description

2263552 1 AN ELECTRONIC BATHROOM SCALE This invention relates to

electronic weighing scales for weighing a person, conventionally known as "bathroom scales", it being understood that they may not necessarily be used in a bathroom.

The invention specifically relates to an electronic weighing scale, for weighing a person and comprising a mechanical part and an electronic part, the mechanical part comprising a casing and a movable weighing platform, which is coupled through a motion converting device to a rotatable disc carrying a set of marks, and the electronic part, for processing the said marks, comprising: an electronic pulse counter; reading means connected to the pulse counter for reading the is said marks and converting them into electrical pulses; a computing and display device connected to the pulse counter for displaying the weight computed according to the number of pulses counted; and a counter starting device controlled by the weighing platform. Such a scale will be referred to as a scale of the kind specified.

In known weighing scales of this kind, the counter starting device generally comprises either a touchcontrol micro-interruptor, or a mercury movement detector. These devices have the disadvantage that they are both complex and costly, and they also have quite a long response time, so that when a user sets the weighing platform in motion, a significant time elapses between commencement of rotation of the disc and the beginning of the count of the pulses which correspond to the marks on the disc. This leads to 2 erroneous measurement of the user's weight.

An object of the invention is to overcome these drawbacks, and in particular to propose a simple and inexpensive electronic bathroom scale which nevertheless provides reliable and accurate weight measurement.

According to the invention, in a scale of the kind specified, the counter starting device comprises a wheel having a plurality of blades and rotatable with the said disc, together with a pulse generating interruptor connected to the counter and arranged to be opened and closed by a leaf spring, the leaf spring comprising a fixed portion secured to a support member carried by the casing and a movable portion adapted to engage the said blades, whereby the initial change in position of the leaf spring triggers the pulse generating interruptor.

Thus, due to the bladed wheel, counting of the pulses by the counter automatically begins as soon as the disc begins to rotate. Thus, when a user mounts the moving platform, the latter is displaced so that, through the motion converting device, which typically comprises a rack and pinion, it causes simultaneous rotation of both the disc and the wheel to take place. Regardless of the initial position of the leaf spring, the commencement of rotation of the wheel causes a sharp change to occur in the position of the leaf spring, thereby transmitting a pulse to the counter so that the latter begins its pulse count. As from that instant, the reading means begin to scan the marks on the disc and to transmit pulses to the counter. In this way a very accurate measurement of the user's weight is 3 obtained.

In addition, this arrangement is particularly simple, inexpensive and well adapted to mass production.

Various features and advantages of the invention will appear more clearly from the description that follows, which is given by way of example only and with reference to the accompanying drawings, in which:

Figure 1 is a partial view in vertical cross section of an electronic bathroom scale in accordance with the invention; and Figure 2 is a top plan view of the same scale as in Figure 1, with a movable weighing platform of the scale shown partly cut away.

As shown in Figures 1 and 2, the electronic bathroom scale includes a mechanical part which includes a casing 2 and a movable weighing platform 3 (only par of which is shown in Figure 2). The platform 3 is coupled to a rotatable disc 4 by means of a motion converting device 5, which may for example be of the rack and pinion type shown, in such a way that the straight line vertical movements of converted into rotation of the disc disc 4 has on its perimeter a set of in practice be in the form of small the platform 3 are 4. The rotatable marks 6, which may radial slots. Index marks printed on the perimeter of the disc could equally well be provided.

In addition, the scale includes an electronic part 7 for processing the marks 6. This comprises a reading means 8 for reading marks and adapted to convert them into electrical pulses. These reading means 8 may for 4 example comprise en emitting diode 9 and an optoelectronic sensor 10, which are arranged on either side of the disc 4 facing towards the marks 6. The reading means 8 are connected to an electronic pulse counter 11, which is itself connected to a device 12 for computing and givipg a visual indication of the weight, displaying the weight computed in accordance with the number of pulses counted. The electronic part 7 for processing the marks also includes a counter starting device 13 which is controlled by the weighing platform 3.

In accordance with the invention, the counter starting device 13 includes a wheel 14 having blades 15, which is rotatable with the disc 4, and in which two adjacent blades 15 preferably define between them an angle of between 45 and 60 degrees, but preferably about 45 degrees. The starting device 13 also includes a pulse generating interruptor 16 which is connected to the counter 11. Closing and opening of the interruptor 16 are controlled by a leaf-spring 17, a fixed portion 18 of which is secured to a support member 23 which is carried by the casing 2. The spring 17 also has a movable portion 19, which is arranged to engage with the blades 15 of the wheel 14 in such a way that the first change in the position of the leaf spring 17 actuates the electrical pulse generating interruptor 16, so that the latter triggers the electronic counter 11.

The fixed portion 18 of the leaf spring 17 is electrically connected to the electronic part 7, while, given that the interruptor includes a fixed contact 20 connected to the counter, together with a movable contact carried by the movable portion 19, the movable portion 19 is able to assume two positions, namely either the retracted position shown in Figure 2 or a contact position not shown. The movable portion 19 is put into its retracted position by engagement with a single blade 15 of the wheel 14 so that it is spaced away from the fixed contact 20. It moves into the contact position when the blade 15 is moved away as the wheel 14 rotates, so that the portion 19 is then applied against the fixed contact 20.

The leaf spring 17 is formed with a slightly projecting contact element 21, such as to make engagement with the free end of each successive blade 15 of the wheel 14 in the retracted position of the spring, so as to amplify the movement of the spring 17 and accelerate its is changes in position, thus reducing response time.

Operation of the scale constructed in this way according to the invention is particularly simple. When a user stands on the platform 3, the latter moves so as to cause simultaneous rotation of the disc 4 and, through the action of the rack and pinion device 5, the wheel 14. Once it starts to rotate, the wheel 14 causes the leaf spring 17 to undergo a sharp change of position due to the contact element 21, so opening and closing the contact between the fixed contact 20 and the leaf spring 17 and thus generating an electric pulse for starting the counter 11. At the same instant, the rotation of the disc 4 causes the marks 6 to move in front of the reading means 8, so that the latter convert each mark 6 into an electric pulse.

Since the counter 11 has been started, it therefore begins to count the pulses which it receives from the reading means 8, starting with the beginning of rotation of the disc 4, and this continues until the 6 platform 3 becomes stationary again.

In this way, weight is measured particularly accurately since the response time of the interruptor is very short, with measurement starting with the commencement of movement of the platform. The response time is further reduced by the provision of the contact element 21 of the leaf spring 17, and by reduction of the angle between the blades 15.

In accordance with another feature of the invention, in which the electronic part 7 comprises electronic components and the wheel 14 includes a spindle 22 defining its axis of rotation and rotatable with the disc 4, the support member 23 is a plate which is removably mounted on the remainder of the casing 2, with the support plate 23 supporting the components of the electronic part 7 together with the fixed portion 18 of the leaf spring 17, and with the spindle 22 of the wheel 14 passing through the support plate 23.

Thus the electronic part 7 is entirely carried by the removable plate 23, and separated from the mechanical part of the scale. This is a simple and inexpensive arrangement which enables the electronic part to be made independently and which facilitates its mass production and any necessary repair. The only coupling between the mechanical part and the electronic part 7 is that occurring at the wheel 14.

7

Claims

1. An electronic weighing scale, for weighing a person and comprising a mechanical part and an electronic part, the mechanical part comprising a casing and a movable weighing platform, which is coupled through a motion converting device to a rotatable disc carrying a set of marks, and the electronic part, for processing the said marks, comprising: an electronic pulse counter; reading means connected to the pulse counter for reading the said marks and converting them into electrical pulses; a computing and display device connected to the pulse counter for displaying the weight computed according to the number of pulses counted; and a counter starting device controlled by is the weighing platform, wherein the counter starting device comprises a wheel having a plurality of blades and rotatable with the said disc, together with a pulse generating interruptor connected to the counter and arranged to be opened and closed by a leaf spring, the leaf spring comprising a fixed portion secured to a support member carried by the casing and a movable portion adapted to engage the said blades, whereby the initial change in position of the leaf spring triggers the pulse generating interruptor.

2. An electronic weighing scale according to Claim 1, wherein the said fixed portion of the leaf spring is connected electrically to the said electronic part, while the interruptor comprises a fixed contact connected to the counter and a movable contact carried by the said movable portion, the latter being arranged to assume two positions selectively, namely a retracted position spaced away from the said fixed contact, into which it is urged by engagement with a single said 8 blade of the bladed wheel, and a contact position in engagement with the fixed contact, into which it is urged by displacement of the said blade as the wheel rotates.

3. An electronic weighing scale according to Claim 1 or Claim 2, wherein two adjacent blades of the said wheel define between them an angle of between 45 and 60 degrees.

4. An electronic weighing scale according to any one of Claims 1 to 3, wherein the electronic part of the scale comprises electronic components and the said wheel has a spindle defining an axis of rotation thereof and rotatable with the said disc, the support member comprising a plate mounted removably on the casing and supporting the components of the electronic part and the fixed portion of the leaf spring, with the spindle of the said wheel passing through the support member.

5. An electronic weighing scale according to any one of the preceding Claims, wherein the leaf spring is formed with a contact element projecting slightly for engagement with the free end of each said blade when the leaf spring is in its retracted position.

6. An electronic weighing scale substantially as described in the foregoing description with reference to the accompanying drawings.