GB2070251A - Recording and measuring profiles of objects - Google Patents

Abstract

Apparatus for checking and calculating the contour of inside radiuses and diameters of objects traces the profile of an object as a series of minute holes in a piece of frame held paper, or indentations into plastics material 20, accurately made by a pointer 6 which either traces a line or is operated manually or automatically by solenoids to make holes so that when enlarged 10, 25, 50 or even 100 to 1, a true picture of the profile can be measured. The pointer moves in unison with a holder 12 and a probe 14 contacting the object, vertical movements of the probe operating a dial gauge 36 and horizontal movements being made by means of a screw 10 and nut 11 moving a carriage 23 on a shaft 3. With conductive materials the mechanism employs a probe which is connected to a battery of low voltage and a bulb indicating when the probe and object make contact, with non-conductive materials the device forms a measurable line. <IMAGE>

Description

SPECIFICATION The inside radius form graph indicator The Inside Radius Form Graph Indicator is primarily an inspection device to be used for checking the radius contour of inaccessible radiuses and forms of diametrical, or irregular shaped objects. Objects such as die, punches, form tools, small cams, finished products and components.

It would essentially be useful to small engineering factories, toolrooms and inspection departments, where speed and accuracy are important, also where in 99% of cases a shadowgraph machine is used for enlarging and measuring exterior forms and radiuses.

The difficulty of measuring the inside radius of a diametrical object to any degree of accuracy is being able to measure exactly central across the cross-section of the diameter.

Various moulding techniques are used, which are inexpensive, but are very time consuming and there is a risk of shrinkage and deformity, which I have experienced in my own occupation.

With the mechanism I have designed, the result will be achieved in five to ten minutes.

There are of course electronic devices already on the market which are highly sophisticated and very expensive that can do the job, but at a price of eleven to fifteen thousand pounds, they are impractical and financially out of reach for small engineering workshops and inspection departments.

There are two methods that can be used with the instrument, the first being with the pointer punching a series of holes into paper or clear perspex to form a graph of the contour to be measured, or two, the pointer scribing the outline of the contour in full. Both being used depending on the type of object to be measured. I must point out that the parts of the instrument would be made to the highest degree of accuracy, for it to function and produce the result being looked for.

Taking the first method with our object being a die, made of steel as shown in Fig. 4, we place it on the Base Plate, item '18' in Fig. 1, centrally in the Vee Block item '17', using the Sliding Support item '16' to hold it rigid.

We then select the desired probe item '14', which is interchangeable, depending on the object and attach it to the Probe Holder, item '12', making allowances for the amount of drop required and the position at which the Probe will start to move. To measure the drop, a dial indicator shown in Fig. 3 can be installed into the attachment item '31' and will also be able to measure the interval at which each hole is pierced. The total movements, horizontally and vertically that can be achieved is 1.000" by 1.000".

The probe itself is made of K.E. tool steel or Tungsten, with the point being .010" in diameter.

The two nuts, item '35', in Fig. 3 are slackened off to allow the Marker Plate, item '24', to move clear of the pointer, item '6', so that the perspex can be slid in behind the sceen. item '20', and the paper also if required. Incorporated on the Marker-Plate bolts, item '25', are compression springs that makes item '24', sprung loaded, for operation.

The pointer has previously been set to be proud of the two shoulders on the supports, items '1' amd '2', by .005", which will act as stops for item '24' when it is compressed, shown in Fig. 3.

After making sure that the pointer is making the hole, by squeezing the Marker Plate against it, we must then make sure the bulb is lighting when contact between the probe and object is being made. A PP9 battery is connected to the Carrier item '4', and Base Plate as shown in Fig.

1, and insulated from each other by two, hard, nylon bushes, item '28', located on the ends of the shaft, item '3'. which fit into the Supports, this will create the circuit between Carrier and Base Plate when the object is touched.

The Marker Plate, mentioned earlier can either be operated physically or automatically by two Solenoid, electro-magnets. These are located at the top of the supports and attached to the Marker Plate as shown in Fig. 2. They are connected to a 240V. A.C. supply shown in Fig. 10, via an on-off button which activates them simultaneously, each having a - 4 kgf pressure which is enough to compress the two springs and move the Marker Plate the desired .020" distance.

The distance from Marker Plate to supports would be set by feeler gauges and by adjusting the two nuts, item '35'.

The vertical movement of the probe is done by item '5', which moves up and down the thread on the Carrier, and with the prpbe holder sprung loaded in the Carrier, we can move the probe vertically at a constant rate.

The horizontal movement is achieved by item '23', the Carrier Adjuster, which is locked onto the shaft by a screw item '9' and adjustment made by the thimble item '11', The end of item '10', being a drive fit into the Carrier, will allow the carrier to be moved horizontally in each direction, the carrier being located onto the shaft by two pins item '8', keeping it vertical by travelling along the keyway in the shaft.

The pointer which is ground to an infinitely sharp point has a falt of .001" on it's tip and will produce a hole in perspex and paper of between .002" and .005" in diameter, the result of this being shown in Figs. '7' amd '8'.

The idea now is to move around the object using the adjusters, touching at as many points as required, each time activating the Marker Plate onto the pointer. The perspex or paper can now be removed and clamped or stuck onto a glass support plate, to be viewed on the shadowgraph machine and enlarged 10, 25, 50, or 100 to 1.

Various probe diameters may be used and various hole sizes may be achieved but the probe radius must be taken away from the final reading of the radius being measured, that's assuming measurement is being taken from the centre lines of the holes.

For example if on the shadowgraph the measurement taken from the radius overlay was - 125", and the diameter of the probe was .010", the resulting measurement would be .010"-:2=.005" -.125"= .120" Radius.

In the second method we still have a simultaneous movement between pointer and probe, but in this instance, instead of piercing holes, the instrument will scribe a line on the surface of a piece of perspex or glass, that is coated with blue indication fluid. The procedure of setting the object is the same, but in this case the Marker Plate and screen are set rigidly and square against the pointer, so that any movement of the pointer and probe will cause a line to be made on the blued surface. In this case the object does not have to be conductive, but there is a slightly bigger risk for error. The lower spring adjuster item '5' is brought up to just touch against the Pointer, this will take the pressure of the second spring that is incorporated on top of the adjustment washer, item '7' Fig. 1. The dial indicator attachment is used to hold this spring down. This spring will be stronger than the one already incorporated on the probe holder, having a difference of 1.5 Ibs.

When the probe has been positioned correctly, only the horizontal movement is used with the lower adjuster being positioned at the required drop, the probe will be forced around the radius at the same time scribing a line on the plate, giving a result as shown in Fig. 9. This can again be enlarged, 10, 25, 50 or 100 to 1, but the same rules applies as to that in the first method, of the radius of the probe being taken away from the result found.

Item No. Description 1 Main support 2 Second support 3 Carrier shaft 4 Carrier 5 Spring adjusters 6 Pointer 7 Adjustment washer 8 Location pins 9 Lock screw 10 Adjuster stud 11 Adjuster nut 1 2 Probe holder 1 3 Probe spring 14 Probe 15 Washer 1 6 Sliding support 1 7 Vee block 1 8 Base plate 1 9 Base plate legs 20 Marker plate screen 21 Marker plate screw 22 Marker plate bush 23 Carrier adjuster 24 Marker plate 25 Marker plate bolt 26 Marker plate nut 27 Marker plate spring 28 Insulating bush 29 Magnifier holder 30 not shown Dust cover attachment 31 Dial indicator attachment 32 not shown Extension probe 33 Lock nuts 34 not shown Sliders 35 Nut 36 Dial indicator 37 Dial indicator nut 38 Solenoid 39 On-off button

Claims (16)

1. A device for measuring and analysing the internal radiuses or forms of objects, that comprises a bridge type construction incorporating horizontal and vertical movement of a probe which travels along a shaft of round section held rigid between two supports that stand on a base plate locating the said object centrally below the said probe which thus indicates the positions of a series of holes that are to be pierced or indented into paper or perspex by the said device thus creating a graph of the said objects radiuses or forms.

2. A device as claimed in claim 1 whereby the said shaft is insulated from the said supports by hard nylon bushes located at each end of the said shaft.

3. A device as claimed in previous claims, whereby a carrier is mounted on the said shaft to house and manoeuvre the said probe horizontally and vertically along the said shaft.

4. A device as claimed in claim 3, characterized by the said carrier being held parallel to the said base plate and shaft by two location pins positioned in the carrier which locate in the keyway that runs horizontally in the said shaft.

5. A device as claimed in claim 1 , whereby a pointer is held rigid at 90 in a probe holder shaft at the opposite end to which the probe would be held and that the distance between the said probe and pointer remains constant on the said holders vertical movement through the said carrier.

6. A device as claimed in claims 1, 4 and 5 whereby the said carrier shaft contains a vertical slot running horizontally approx., three quarters of its total length.

7. A device as claimed in claim 3 and 4 characterized by the said carrier containing an exterior thread for vertical adjustment and a screw and thimble adjuster for horizontal movement for the said probe and pointer.

8. A device as claimed in claim 7, whereby the said vertical adjustment thread contains a vertical slot for aligning the said pointer squarely to the marker plate.

9. A device as claimed in claims 6, 7 and 8, whereby a pring is incorporated inside the vertical thread of the carrier.

10. A device as claimed in claims 5, 7, 8 and 9 whereby the said spring, probe and pointer are held in tension for vertical movement by spring adjusters on the said carriers exterior thread.

11. A device as claimed in claims 1 and 8 whereby a marker plate is held parallel with the said base plate and is connected to the said supports in a vertical position.

1 2. A device as claimed in claims 1 and 11, wherein the said marker plate is sprung loaded in the supports.

1 3. A device as claimed in claims 1 and 2, which incorporated two solenoid electro-magnets attached to the exterior of the said supports which are in turn connected to the said marker plate.

14. A device as claimed in claims 1 and 7, including vertical and horizontal measuring instruments.

1 5. A device as claimed in claim 1, whereby a small electrical current will pass between the said probe and object when they make contact indicating this said contact in the form of a light or buzzer.

16. A device as claimed in claims 1 and 11, whereby a screen is positioned on the said marker plate to hold the said paper or perspex square and vertical to the pointer.

1 7. A device as claimed in claim 1, substatially as herein before described with reference to and as illustrated in the accompanying drawings.