GB2168156A - Measuring apparatus - Google Patents

Abstract

Apparatus for measuring the sizes of socks, stockings, tights etc, in which the sock to be tested is mounted on an apparatus comprising foot and/or leg shaped formers which are segmented so as to be expandable inside a sock whilst retaining their original shape. Load sensors are provided at various points on the formers to enable the socks to be measured. A microprocessor controls a measuring programme. <IMAGE>

Description

SPECIFICATION Measuring apparatus The present invention relates to measuring apparatus and more particularly to apparatus for measuring the size of socks or stockings.

Hereinafter the term sock will be used but it is to be understood that it includes socks, stockings and tights etc. designed to be worn on the legs and feet.

In the production of a sock, there are many variables which determine the size of sock produced, such as yarn tension, stitch-cam position, needle alignment, operation of the sinkers etc. These variable factors make it extremely difficult to consistently produce a sock with the same size foot and leg length in the relaxed conditions. During the course of a day, the temperature and humidity change on the knitting machine lines. These affect the viscosity of the oil impregnated in the yarn used to make the socks and as a result alter the friction characteristic of the yarn during the knitting process. Although a machine may be set to make one particular size of sock, it can be producing a different size as the humidity and temperature varies.Therefore, samples need to be inspected in the pre-finishing stage to monitor the changes, as weli as at the finished stage for quality control purposes.

At present, the measurement of socks is being carried out under hand stretch (flat measurement against ruler), lateral stretch with a falling weight, compressed air devices, constant weight devices and using volumetric foot formers for stretch socks. However, the present methods require a varying degree of human influence with poor repeatability and consistency as a result. Constant weight or constant pressure devices might permanently deform a sock produced with more delicate yarn and the size measurement has no real meaning as to how it would fit on a persons foot.

Using volumetric foot formers will only verify that the sock fits a particular foot size, as no load (or pressure) measurement can be taken; there is no way of finding out the load (pressure) on the foot and whether it is comfortable for the wearer.

It is an object of the present invention to obviate the above disadvantages by providing an apparatus for the automatic measurement or comparison of sock sizes in which the stretching and measuring operation is carried out and controlled by a microprocessor and is independent of operator influence.

According to the present invention there is provided an apparatus for measuring sock size including a foot or leg former in the shape of a foot or leg for the reception of a sock to be sized, in which the foot or leg former comprises a plurality of segments at least one of which segments being movable to expand to the size of the sock to be tested.

In a first preferred embodiment the leg former is a solid form, only the foot being expandable.

In a second preferred embodiment the foot former is a solid form, only the leg former being expandable.

In a preferred embodiment one or more of the segments in either the foot or leg former is provided with a load sensor to sense the load exerted on that segment by the sock under test.

Preferably the expansion of the foot and/or leg former is performed under the control of a microprocessor which is programmed to expand each segment in a controlled manner to a selected sock size or until one or more of the pressure sensors detects a predetermined pressure or pressures.

The foot former preferably comprises six toe segments six centre foot segments and three heel segments. Load sensors are preferably positioned on the central toe centre foot and heel segments.

The leg former preferably comprises six segments one of which is fixed, the other five being relatively movable thereto to provide the expansion.

The leg former is preferably provided with a plurality of load sensitive switches which are positioned longitudinally on the leg former and which are operative to indicate the length of sock on the leg.

The leg former is also preferably provided with a plurality of load sensors positioned at selected points. In a particular embodiment sensors are provided at the ankle, calf and thigh positions.

Preferably the foot segments are mechanically linked such that the foot form is expandable in a progressave manner. Also preferably the leg form segments are mechanically linked to each other so that the leg form expands in a progressive manner.

Embodiments of the present invention will now be described by way of example with reference to the accompanying drawings in which: Figure 1 shows a typical sock with the normal dimensions marked; Figure 2 shows a leg illustrating the ankle calf and thigh measurements; Figure 3 shows an apparatus for measuring the size of socks according to the present invention; Figure 4 shows the foot and leg forms of the apparatus of Figure 3 in greater detail; Figure 5 is a cross-section of Figure 4 along line A-A'; Figure 6 is a cross-section of Figure 4 along line B-B'; Figure 7 shows the heel portion of Figure 4 in greater detail; Figure 8 shows a cross-section of the leg portion along lines C-C'; Figure 9 shows in detail the mechanical link ages of the foot segments; Figure 10 shows the vertical extension system for the foot segments;; Figure 11 shows the horizontal sideways extension system for the foot segment; Figure 12 shows the horizontal forwards extension system for the foot segment; Figure 13 shows the mechanism for expansion of the leg; Figure 14 shows a vertical cross-section of a possible load sensor suitable for the present invention; Figure 15 shows a plan view of the sensor of Figure 14; Figure 16 shows a first type of sensor pad for use with the load sensor of Figures 14, 15; Figure 17 shows a second type of sensor pad for use with the load sensor of Figures 14, 15; and Figures 18 (a), (b) and (c) shows a flow diagram for the operation of the apparatus under the control of a microcomputer.

With reference now to Figure 1, a typical sock 10 is shown and the critical dimensions are indicated as follows -calf girth 12, minimum leg girth 14 (normally at or near the ankle), heel girth 16, instep girth 18, joint girth at toes 20, foot length 22 and leg length 24.

With reference to Figure 2 in addition for a stocking the thigh girth 26 is an important measurement.

With reference to Figure 3 the apparatus includes a foot former 30 leg former 32 combined as shown. The foot and leg formers comprise a number of segments referred to in greater detail with reference to Figures 4 to 8.

The foot and leg sections may be expanded by a control unit 34 under the control of a microprocessor 36. A number of load sensor pads 38-58 (as described hereinafter with reference to Figures 12 and 13) are positioned at desired locations on selected segments.

Each load sensor is linked to the control unit 34. A series of load sensitive ON/OFF switches 59 are provided to sense the leg length of the sock when expanded to a particular size.

The operation 6f the apparatus will now be described prior to a description of the mechanical features shown in Figures 4 to 15.

The stretching and measuring operation is carried out and controlled by the dedicated microprocessor 36 and control unit 34 and is totally independent of operator influence. After the loading of a sock onto the foot and leg former by an operator, operation of a start key on keyboard 60 of microprocessor 36 will cause the formers 30, 32 to expand volumetrically to one size smaller than the expected sock size and then retract, for a number of cycles (say 5) to ensure the sock is in a relaxed state. The sock is then stretched volumetrically to a certain limit and shape normally encountered on the size of foot defined by the operator, before measurements are obtained simuitaneously regarding to foot length, calf girth, mid foot girth, ball girth and leg length in relation with the loads (pressure) obtained by sensors 38-58 over the foot former.

The cycling operation is not essential, but may be used to reduce the effect of the finishing operation which often causes an artificial stiffness in the sock known as the 'milling' effect.

The measurement of size of a garment, by stretching it, is meaningless if the applied force or pressure is uneven or inconsistent, especially with knitted products. The extension (expansion) depends upon the magnitude of the applied force or pressure, hence the apparatus is provided with two modes of operation which can be chosen by the operator, depending on certain requirements.

(i) Mode 1-Size Controlled With this mode of operation, the operator will only be required to input into the microprocessor the expected size of the sock and coding for the material; then the operation can be started.

The sock is expanded volumetrically by the foot and leg former until the required circumferences for that size (e.g. ball girth, foot length, calf girth etc) are obtained, then the loads (pressures) at the different sensors 38-58 over the foot former are recorded, displayed and/or compared with an established standard.

(ii) Mode 2-Load (pressure) Controlled When this mode of operation is selected, the operator will only need to input the loads required at certain points or code according to the established standard. The sock will then be expanded from one size to the next until the loads (pressures) are obtained at the corresponding sensors. At the end of the operation, the circumferences (regard to foot length, ball girth, calf girth etc) are recorded, displayed and/or compared with the standard.

This mode of operation is required for inspection of medical/surgical support hosiery as load (or pressure) on certain areas is essential and critical.

The system will cover the full range of men's socks from size 6.1/2 to 11. At the fully retracted position the volumetric foot former is equal to size 6 for easy loading of a sock. A similar system, albeit somewhat smaller, can be used to cover the full range of childrens socks.

The essence of the system is its total independence of operator influence for reliability and consistency. Its simplicity and compactness will encourage the use of the system as very little training is required to operate it.

For sock manufacture, the system can be used to measure a sock: i) during the design and sampling stage; to help a designer to produce a correct specification for production. Hard-copy printout can be obtained for record via printer 62.

ii) following the knitting stage (usually open toe); with the toe clipped, the sock can be measured to monitor the production process.

iii) at the finishing stage; for quality control purposes.

For sock retailers, the system can be used to inspect samples and compare with company standards (which can be programmed into the microprocessor memory e.g. EPROM), then the digital display unit or printer will acknowledge the result whether it is rejected or accepted.

In order to develop a standard for comfort of a wearer, load sensors 38-58 are mounted over the foot/leg former to monitor the loads (pressures) at each sensor's point.

In the embodiment shown eleven sensors are provided but the number may be varied to cope with varying test requirements. The system consists of the following: Figures 4 to 8 illustrate the method for the volumetric expansion of the foot/leg former.

With three separate driving mechanisms, motors and controls, three displacements (expansion) 'a', 'b' and 'c' can be achieved independently, so that the foot can be expanded to a required foot length, foot girth and leg girth etc.

Leadscrews and linkages are used to convert rotational movement into linear movement as shown in Figures 9, 10 and 11. In Figure 9 the internal mechanics of the foot are shown before encasing in for example fibre glass to give the foot shape.

The mechanics shown in Figure 9 are for the foot former expansion. The leg former expansion may be of the same format using leadscrews and appropriate motor drive flexible drive shaft and leverage assemblies to achieve the expansion of the leg form as shown in Figure 8. Thus Figure 9 shows the simplest version where the foot expands in three dimensions, Figures 4 to 8 illustrating the complete foot and leg form expansion.

The leg and foot shapes formed for example using a fibre glass cladding may be of any desired shape-for example the "standard" foot shape as given by any Bureau of Standards.

As an alternative to a hard fibre glass shape softer shapes can be obtained using for example varying grades of rubber covering.

A stepper motor (not shown), through a flexible shaft, drives a leadscrew on the fixed member of the leg section, to expand the leg in the Z-axis to a maximum displacement of 'a' (as shown in Figures 4 and 8).

A further stepper motor (not shown), drives the two leadscrews on the foot section and another two on the leg section through flexible shafts. On the foot section, the leadscrew 70 on the lower fixed segment (as shown on Figures 9, 10 and 11) expands the upper foot section and heel along Y-axis to achieve maximum displacement of 'b', (see Figures 5, 6 and 7) and at the same time expands the foot section in the X-axis to achieve a maximum displacement of 'b/2'. Similarly the top leadscrew 72 expands the foot section along the X-axis to achieve a maximum displacement of 'b/2'. On the leg section, the leadcrews on the fixed and movable segments expand the leg along the X-axis the same way as in the foot section.

With reference to Figure 12, a yet further stepper motor (not shown), through a flexible shaft 73 (Figure 12b), drives the leadscrew 74, for the toe extension along the Z-axis to compensate the movement 'a' to a maximum of 'a + c' in this axis to achieve the foot length required.

The method adopted for the expansion of the foot former not only maintains the linearity of the foot former throughout its expansion, but also ensures an even extension of fabric over the circumference of the foot former to reduce the effect of surface friction.

With reference now to Figure 13 an expansion mechanism for the leg is shown to enable the leg to expand as shown in Figure 8.

The mechanism is shown in front and side elevations Figures 1 3a and 1 3b and with various parts shown in projection drawings.

In Figure 13b the uppermost member 80 is the fixed member of Figure 8, the cross leverage arrangement 82, 84, 82', 84' moving the leg segments in the direction to provide movement "a" with the guidance of guide pins 85, 85' by lead screws 86, 88 driven via flexible shaft 90 from a stepper motor (not shown). The movement of the leg members to provide the expansion b ('b/2' and 'b/2') is provided by lead screws 92, 92' and 94, 94' which actuate respective levers 96, 98 to move the leg members with the guidance of guide pins 100 etc (only pin 100 is shown for clarity of the drawings).

The linkages 82, 84, 82', 84' operate via cut outs in the member 102 as shown in Figure 13c.

Preferably the two shafts 92, 92', 94, 94' are driven by a single drive shaft via a universal coupling 104 (not shown in detail).

Load transducers as shown in Figures 14 and 15 with different sensor pads are used for measurement of load (or pressure) over the foot former. The sensor pads shown in Figures 16, 17 are fitted to the load transducers of Figures 14 and 15 so as to bend the cantilever arm 106 thus changing the outputs from a foil gauge (strain gauge) 108 to give the load imposed on the arm 106. The sensor pad, its shape and protrusion are chosen in order to minimise the effect of surface friction on the former and to maintain the consistency of the load measurement. Two differ ent types of sensor pads may be used (as shown in Figures 16 and 17). Typically the first type as shown in Figure 16 is best shaped for use on the leg and the second type as shown in Figure 17 on the foot, with a protrusion of 1.5 mm above the surface of the foot former.

Load sensitive switches 59 (shown in Figure 3) are arranged on the leg to measure the true leg length when the sock is expanded on the volumetric foot.

The control unit 34 includes 3 stepping motors, drives and 24V DC supply, + 5V DC supply and 11 strain gauge amplifiers, 16 channels 8 Bit A/D converter and other electronic interfaces. A cooling fan is also included in the unit.

The motors are connected with flexible shafts to drive the volumetric foot former which is mounted on the top of the control unit.

A Rockwell AIM 65 desk top microprocessor 36 is used for controlling the system and signal processing. The AIM 65 includes assembler, basic and extended memory of 32K (RAM). It also has built in full size terminal style keyboard 60, 20 character alphanumeric display 61 for interactive operator communication and 20 columns printer 62 for hardcopy printout.

The above description explains the arrangement for the most complex requirement for the system, but other varieties, with a reduced number of sensors, simplified keyboard and less movable segments may be incorporated in other versions.

Figures 18 (a), (b) and (c) show a flow diagram for sequential operation of the apparatus in size (mode (A)) or pressure (mode B) to measure socks to give the pressure exerted by a sock when the former is expanded to a certain size or to expand the former until a set pressure or pressures are reached and to record the size of the former at those pressures.

Claims (15)

1. An apparatus for measuring sock sizes including a foot or leg former in the shape of a foot or leg for the reception of a sock to be sized, in which the foot or leg former comprises a plurality of segments at least one of which segments being movable to expand to the size of sock to be tested.

2. An apparatus for measuring sock sizes as claimed in Claim 1, in which the leg former is a solid former, only the foot former being expandable.

3. An apparatus for measuring sock sizes as claimed in Claim 1, in which the foot former is a solid former, only the leg former being expandable.

4. An apparatus for measuring sock sizes as claimed in any preceding claim, in which one or more of the segments on either the foot or leg former is provided with a load sensor to sense the load exerted on that segment by the sock under test.

5. An apparatus for measuring sock sizes as claimed in any preceding claim, in which the expansion of the foot and/or leg former is performed under the control of a microprocessor which is programmed to expand each segment in a controlled manner to a selected sock size or until one or more of the pressure sensors detects a predetermined pressure or pressures.

6. An apparatus for measuring sock sizes as claimed in Claim 1 in which the leg, foot and heel segments are synchronised through the microprocessor and the stepper motors such that the leg, foot and heel formers are collectively expandable in a progressive manner.

7. An apparatus for measuring sock sizes as claimed in any one of Claims 1, 2, 4, 5 or 6, in which the foot former comprises six toe segments, six centre foot segments and three heel segments.

8. An apparatus for measuring sock sizes as claimed in Claim 7, in which load sensors are positioned on one or more of the toe, foot and heel and leg segments.

9. An apparatus for measuring sock sizes as claimed in any one of Claims 1, 3, 4, 5 or 6, in which the leg former comprises six segments, one segment being fixed, the other five segments being relatively movable so as to provide the expansion of the leg.

10. An apparatus for measuring sock sizes as claimed in Claim 9, in which the leg former is provided with a plurality of load sensitive switches which are positioned longitudinally on the leg former and which are operative to indicate the length of sock on the leg.

11. Apparatus for measuring sock sizes as claimed in Claim 9 or Claim 10, in which the leg former is further provided with a plurality of load sensors positioned at selected points.

12. An apparatus for measuring sock sizes as claimed in Claim 11, in which the sensors are provided at the ankle, calf and thigh positions.

13. An apparatus for measuring sock sizes as claimed in Claim 1 or Claim 2, in which the foot former segments are mechanically linked such that the foot former is expandable in a progressive manner.

14. An apparatus for measuring sock sizes as claimed in Claim 1 or Claim 3, in which the leg former segments are mechanically linked to each other such that the leg former expands in a progressive manner.

15. An apparatus for measuring sock sizes constructed substantially as herein described with reference to the accompanying drawings.