CA1181611A - Registering apparatus - Google Patents

Abstract

ABSTRACT
An apparatus for registering accelerations and retardations includes a basic structure (1,2) on which an inertial mass is suspended in spring means and adapt-ed to guide a writing means (C) coacting with a web (80) of registering medium, which is arranged for runn-ing substantially transverse the direction of movement of the writing means (C). The spring means includes two spring elements of which the first is adapted to bias the mass towards a normal position (60) with a force attaining a fraction of the force the mass maximally exercises on the first spring element under the action of gravity, while the second spring element is adapted for starting to exercise an elastic deformation resist-ance to the displacement of the mass when the latter is moved past a displacement position (61;62) substant-ially situated at a distance from the normal position (60) corresponding to the length by which the mass maximally deforms the biassed first spring element under the action of gravity minus a length correspond-ing to the deformation of the first spring element, occurring at a loading thereof with a force of the same order of magnitude as said biassing force.

(Fig. 1)

Description

TITLE OF INVENTION
_ _ _ REGISTERI~G APPARATUS

TECHNICAL _IEL~_ _ The invention relates to an apparatus -for registering accelerations and retardations, comprising a basic struct-ure on which an inertial mass is suspended in a spring means and adapted -for controlling a writing means coacting with a web of registering medium, which is adapted for running substantially transverse the direction o-f movement of the writing means.

BACKGROUND ART
Known apparatuses for registering accelerations and retardations are burdened with disadvantages, e.g. in the form of a single narrow measuring range, labile neutral position indication, ineffective dampening, especially dampening in the neutral position, while they also lack attitude registering facilities, and have a registering medium feed varying with ambient temperature and/oT have registration which is sensitive to temperature.
Registering apparatuses of the type mentioned are customarily utilized for investigating the forces to which goods are subjected during transport. From experience, such forces can be divided into two categories, namely vibrat-ions and shocks. Vibrations of particular interest are those occurring in such situations where goods are trans-ported by a lorry or truck, the vibrations then constitut-ing an indication of the truck springing and road smooth-ness7 and norma]ly have an amplitude of at most about 2 g.
Shocks are usually associated with goods handling and can have an amplitude of up to 100 g. Goods are usually packed in SUC}l a way that they can withstand minor shocks of up to 10 g, at least when the packed goods have a given pre-scribed orientation relative to the substructure. Although packing can protect goods against shocks of a given ~' relatively large amplitude, it is not at all certain that the goods will withstand vibrations of relatively low amplitude for a relatively long time, at least in soine attitudes.
Apparatuses of the kind in question is norma]ly attached directly to the goods which is to be transported ?
and should there-fore have relatively small physical dimens-thes,e dimensio~s lons/determlnlng the space for the components ln the appa-ratus. If it is desired to utilize motors, e.g. electric motors, for driving the registering medium, usually a paper web, a problem arises with the batteries or accumulators used for the motor drive, since they have a characteristic which is heavily dependent on temperature. Another dis-advantage in connection with registration of measured values is with regard to the type o-f writing means which is used. For example, if the writing means comprises a stylus which scores a track in a plastic mass on the registering medium, there is always the risk that the sti-f~ness of the mass varies with temperature so that the sensitivity o~
the apparatus will vary with temperature. This also applies to the cases where the tip of the writing means runs over a pressure-sensitive registering medium which is also sensi-tive to temperature with respect to e-f-fective indication.

OBJE_ One object of the invention is to provide a register-ing apparatus reducing OT eliminating at least some of the above-mentioned disadvantages with known apparatuses of the type in question.

SUMMARY OF INVE~TION
_ The inventive apparatus includes a basic structure on which an inertial mass is suspended in a spring means, and adapted to control a writing means coacting with a web of registering medium which is adapted for running sub stantially transverse the direction of movement of the writing means~ and is essentially distinguished in that the spring means includes two spring elements~ of which the ~irst is adapted to bias the mass towards a normal posit-ion with a force attaining a fraction of the force with which the mass maximally acts on the first spring element under the action of gravity, a31d of which the second spring elelnent is adapted for beginning to exercise an elastic deformation resistance to the displacement of the mass when it is moved past a position of displacement situated at a distance from the normal position substantially correspond-ing to the length the mass maximally can deform the first element under the action of gravity minus a length corresp~
onding to the deformation of the first spring element, occurring at a loading thereof with a force of the same order of magnitude as said biassing force.
With an apparatus in accordance with the invention there is thus afforded two sequential measuring ranges which allow registration o~ all interesting forces, simulta-neously as an indication is obtained as to the attitude o-f the apparatus, and stable rest positions are afforded for the mass both in the attitude defined by the normal posit-ion and in the attitudes displaced by 90 with respect thereto.
Said distance de-fines the amplitude of the writing means within the first measuring range extending up to 0.9 g, for example. If the mass is moved past said position of displacement, the second spring element comes into action also. The second element can then be selected such that a movement of the mass past said position a length corresp-onding to said distance corresponds to an acceleration ofsay 25 g. There is thus obtained a useful registration of both small and large forces acting on the apparatus. By the inventive embodiment of the apparatus, effective neutral position damping is obtained for the mass, irrespective of whether it is in a normal position or in an attitude which is 90 from the normal position. This damping can be traced to the biassing force towards the normal position or to the idling force against the second spring element in the rest positions which are 90 phase shifted. The resonance efEec~s which could occur in the apparatus are inhibited by said normal and rest or idling position dampings.
To advantage, the apparatus can be made such ~hat the mass has the -form of a pendulum pivctably mounted on a shaft and having a dog pin, there being a -first fork com-prising two separate first shanks pivotably mounted on the shaft astride the dog pin and a guiding pin, which is rigidly attached to the base structure in a position corres-ponding to the neutral position of the pendulum. The first spring element may then be coupled between the first shanks to limit their swinging apart. A second fork comprising two second shanks pivotably mounted on the shaft can further be arranged a;tride the dog pin and guiding pin, stopping means being arranged to limit the angle contained between the second shanks to a value corresponding to said distance.
The second spring element is suitably connected between the second shanks to limit their turning apart.
The biassing force suitably attains about lO~o of the -force with which the mass maximally can act on the spring means under the action of gravity. The edges facing towards each other of the first shanks are s~tably adapted for be-ing in contact with both dog pin and the centre pin in the neutral position of the pendulum, the dog pin being mounted to advantage at the centre of gravity of the pendulum and parallel to the sha-ft.
The second spring element is suitably formed and adapted so that it affords substantially greater resist-ance to the movement of the mass than the firs~ spring element. ~or a deformation corresponding to said distance, the second spring element can thus be arranged to afford a resistance force which is easily selectable and, for example, 25 times as great as the resistance force a-fford-ed by the first spring element.
The writing means suitably includes a carriage which is guided for movement transverse the direction of movement of the web and which carries a styllls, consisting to advan-tage o-f graphite and which is adapted -for being in contact with the web, at least in the operative condition of the apparatus, an arm carried by the dog pin being connected to the carria~e, possibly via link means. The web can consist of paper when the stylus consists of graphite or the like.
To advantage, the pendulum is mourlted in ball bearings on the shaft. Two diametrically opposing surfaces of the pendulum are suitably made as circular arcs with their centre at the shaft, corresponding complementary abutment surfaces being arranged in the basic structure in conjunct-ion with said pendulum surfaces, the clearance between the pendulum and the base structure at these arcuate surfaces suitably attaining the maximum permitted radial play of the roller bearings. Stop means may be arranged on either side of the pendulum to limit its oscillating movement to an amplitude corresponding to the maximum amplitude of the writing means.
The registering means defined so far has solely been stated to include one inertial mass, but it should be quite clear that the apparatus can to advantage include a second and a third inertial mass, which are substantially arranged to be made and suspended similar to the first-mentioned inertial mass, and connected to associated writing means in an analogical mode, each of the inertial masses being adapt-ed movable in one of three dimensions at right angles to each other. Driving means for the registering medium com-prises to advantage of a clock-controlled motor spring, friction compensating means suitably being adapted for com-pensating for the diameter increase of the roll onto which the web is wound.
The registering means is suitably made as a cassette consisting of two open boxes which are connected to each other by hinges. The inertial mass, as well as its associated spring me2rls and suspending means, as well as the writing means are arranged in one box. The r~gister;ng me~ium is arranged in the other hox as well ~s poss-ible driving means for the medium. The writ;ng means can com-prise a tubular holder extending in the direction of anormal to the parting plane of the casse~te. The hol(1er is adapted for guiding a graphite stylus with a diameter of 0.2 mm, for example. A spring means is arranged under the holder to carry and bias the graphite stylus against the medium in the closed condition of the apparatus. By such a cassette embodiment in the apparatus, there is afforded very simple exchange of registering medium, and graphite can be easily used as stylus. It has namely been found that graphite styluses are excellent material, its ability to write on, and its friction against recording paper also being independent of low ambient temperatures.
The invention will now be described in detail in the following in the form of an example while referring to the appended drawing.
DRAWING
Fig. 1 schematically illustrates an apparatus in accordance with the invention. Fig. 2 is a view taken along the line II-II in Fig. 1. Fig. 3 is a view taken along the line III-III in Fig. 2. Fig. 4 is a view taken along the line IV-IV in Fig. 3. Fig. 5 is a view taken along the line V-V in Fig. 2. Fig 6 is a view taken along the line VI-VI
in Fig. 2. Fig. 7 illustrates the combined spring constant for the spring means incorporated in the apparatus in accordance with the invention. Fig. 8 schematically illu-strates a view taken along the line VIII-VIII in Fig. 1.
Fig. 9 schematically illustrates a view taken along the line IX-IX in Fig. 8. Fig. 10 is a side view of a wrinting means incorporated in the apparatus in accordance with the invention. Fig. 11 is a view taken along the line XI-XI in Fig. 1. Fig. 12 schematically illustrates an apparatus in accordance with the invention in an operative condition.

EMBODIMENT EXAMPLE
Two alike boxes 1,2 are illustrated in Fig. 1, and S they are connected to each other by means of hinges 3, for easily being put together and locked by means of the lock 4, to define a closed space in which the components of the apparatus can be protectively placed.
The box 1 contains three acceleration and retardat-ion sensing means 7, each of which is adapted for sensing in one of three dimensions mutually at right angles. The means 7 are connected to writing means A,B and C, respect-ively, which are guided for displacement along rails 161 and 162.
A paper web 80 is arranged to run from a supply 82 to a winding-u,p roller 155 in the box 2 under the action of a clock-controlled driving mechanism 140,141,142 (see Fig. 113. The web 80 is driven substantially at right ang-les to the rails 161, 162.
The inertia-sensing means 7 can have substantially similar embodiment and are illustrated in Figs. 2-6. From Fig. 2 it will be seen that a sensing means 7 includes a pendulum 31 mounted on a shaft 90. The shaft 90 is journ-alled by means of ball bearings 81 in the box 1. The pen-dulum 31 also carries a dog pin 91, which is preferably arranged at the centre of gravity of the pendulum 31 and parallel to the shaft 90. An arm 103 is carried on the shaft 90 and pin 91. A first fork 100 and a second fork 200 are pivotably mounted on the shaft 90, e.g. by ball bearings not shown. The first fork 100, which is more closely illustrated in Fig. 3, comprises two separate shanks 101,102 pivotably mounted on the shaft 90. The fork 100 sits astride the dog pin and a guide pin 92, the latter being rigidly mounted in the box 19 in a position corresp-onding to the normal position of the pendulum 31. A first spring e~ement 21 is coupled between the shanks 101~102 of the first fork, to limit -their swinging apart. The spring 21 can have a wishbone shape with inw~rly bent cnds arrang-ed to engage in recesses 121 on the outside of the respec-ive shan~ 1n1,102. The idling moment thus e~ercised by -the spring 21 on the shanks 'l01,102 can then be set simply.
From Fig. 3 it is apparent how the arm 103 connects to'an arm portion 1'13 made rigidly fixed thereto. ~t its free end the arm portion 113 is coni1ected to, a link 106, to which there is attached a writing means C. The link 106 is to advantage made from thin piano wire. The end connecting the arm 113 to the link 106 can be made with an L profile, the upwardly directed link in Fig. 2 of this pro-file can have a slit 104, while the other leg can have a hole 105, as will be best seen from Figo 4. In order to afford a simple and accurate turnable connection between the arm 113 and piane wire 106, the end of the wire 106 can be bent round 270 as illustrated at 107 in Fig. 4. The end portion of the wire can then be simply pushed down into the hole 105 and the straight main portion of the wiTe 106 can be eased into tl1e slit 104. It should be emphasized here that by this means a right angle between the straight portions of the wire l 06 can be accurately obtained without any junction radii, as would be the case with a simple bend of the wire end. In this connection it is especially pointed out that the end portion of the wire 106, which is to be inserted in the hole 105, must have very small length if de:Election phenomena are to be avoided. Similarly, the wire 106 should have very small diameter to enable bending it in the area between the writing means C and arm 113.
The stroke of the writing means within the first measuring range defined by the spring 21 will be the same, irrespective of ~hether the pendulum is in its normal position (S0) or in one of the two attitudes ~S1; -S1) displaced 90 thereto.
If thc apparatus should have an attitude such that ~3~
the pendulurn rests with a force ~F against the combined action of the springs 21,Z2 and is thereby subj~cted to the action of a force corresponding to a heavy acceleration or retardation, this would become apparent by the writing means being moved past the position S1. The combined spring constant, as determined by the springs 21,22 and their leverage relationships, then provides a translation factor between the movement of the writing means past S
and the acceleration or retardation -force acting on the pendulum. Darnping is provided for breaking down possible resonances in the apparatus, when the mass is displaced past the normal position S0 and the position S1.
If so desired, the spring 22 can already be allowed to exercise displacement resistance at a load corresponding to S - ~F (0.9 mg). In this way the two measuring ranges S0-S1; S1-S2 will directly tie up with each other. It should be quite clear however, that the spring 22 can be adapted to begin action first at a force application corresponding to S1 ~1.0 g). In the~first-mentioned case, ~he combined spring constant of the springs 21,22 is so much higher than the spring constant o-f the spring 21 that the force increment between 0.9 g and 1.0 g does not cause any appreciable displacement of the writing means past the position S1.
As will be seen from Fig. 1, two means 7 can be arranged in a common plane, but oriented in directions at right angles to each other. There is thus obtained regist-ration of force application in two dimensions mutually at right angles. The means 7 can be substantilly identical, only the positions of the force transfer arms 113 being different.
The third means 7', for registering the application of force in a direction normal to the bottom of the box 1, is shown in Fig. 8, wl1ere it will be seen that the sensing means 7' conforms in all essentials to the means 7 illu-strated in Figs. 2-6, although there is a translation I () mechanism 213-220 arranged for translating the osci:llating movlnent of the pendulum to a disp:lacerneilt movement of t`he writing means B on the rails 161,162. The translating mechanism includes a shaft 220 on the arm 113. The shaft 220 carries t-wo ball bearings 219. One ball bearing 219 runs on a track 217. The other ball bearing 219 runs on a truck 218. The tracks 217,21S are mounted on a bracket 216 attached to an arm 213 which is mounted at 214. The -free end of the arm 213 can be made similar to the end o-f the arm 113 shown in Fig. 2, the connection between the writing means B and the arm 213 being adapted similar to what can be seen from Figs 3 and 4.
By the embodiment apparent from Fig. 9 there is pro-vided a "no-play" translation of the movement of the arm 113 to the wire 106.
Fig. 10 illustrates how the writing means C, for example, can be made. The writing means A and B are made analogically. The means C includes a clamping screw 108 for fastening the end of the wire 106. The writing means also includes a leg 171 carrying a narrow tube 170. A leg 172 joins the leg 171, and a leg 173 joins the leg 172 at right angles. A cushion 163, e.g. of Teflon~3 is arranged OII the leg 173. The cushion is intended to rest against the rail 161. A leg 175 extends at right angles from the leg 171. The corner area between legs 171 and 175 is adapted for guidance by the rail 162. At its lower end, the leg 175 is bent 180 and joins onto a leg 176, joining onto which at 90 there is a leg 174.
The legs 171,172,173 constitute support for carrying the tube 170 in the desired direction. The legs 175,176, 174 constitute a spring means adapted for actuating a pen-cil lead 199 which is guided by the tube 170. The legs 175, 176,174 are arranged and made such that the point of supp-ort of the lead 199 on the leg 174 only moves in the direct-ion of the lead 199. This is most simply provided by allow-ing the junction between the legs 171,175 to be relatively stiff, allowing the leg 175 to be downwaldly tapering to enable bending out to the left in Fig~ 10, and allowing the legs 176 and 17~ to be bent do~in rclatively to the leg 175.
In accordance with the invel1tion, the use of graphite or soft pencil lead for the stylus 199 is preferred. In or~er to provide a reasonable resolution oE the registration, the stylus 199 should have a diameter in the order of magnitude of 0.2 mm. With the arrangement according to Fig.
9 there is provided automatic feed of the stylus 199 1~ through the tube 170 without the risk of breaking the lead.
The stylus coacts with a registering paper 80 ~see Figs. 1 and 11). The paper 80 runs over a flat plate 81, one end area of which is formed as a store 82 for the paper web. The web is attached to a winding-up roller 145 which 1~ is in frictional contact with a driving roller 141. The driving roller 141 drives a roller 142 in contact with the paper web 80. As indicated in Fig. 11, a tensioning roller 143 can be mounted in the box 1 via a spring 144 such that the roller 143 presses the paper web 80 against the roller 142 when boxes 1,2 are swung together. The driving roller 141 is driven by a clock-controlled mechanism 140, prefer-ably a spring driven mechanism. At its right hand end in Fig. 11 the plate 80 is pivotably mounted on a shaft 83 so that the plate 80 and the store 82 can be swung upwards to make the mechanism 140 accessible, which can thus be simply wound up.
As will be seen from Fig. 11, registering paper can be very simply placed in the apparatus without hindrance from writing means. It should be noticed that the writing means A,B,C first come into cont~ct with the registering paper 80 when the boxes are s~lng together. This also signi-fies that new styluses 199 can be easily placed in the writing means.
It should also be noted that a further writing means T can be arranged in the box 1 on the rails 161,162. The means T can be made substanti<~ly similar to the means A-C, although the means T is suitably spring-biassed in a normal position, there being a device 121 (see Fig. 1), e.g. in the form of an opening through the wall of the box 1 to allow the possibility of displacing the means T sideways along the rails 161,162 so that a mark is obtained on the paper 80 when such action is taken. Such marks then consti-tute a notation of the time at which the means T is actuat~
ed, and can be utilized as reference times in connection with assessrnent of the registra~ions obtained on the web 80 by the writing means A-C.
Turning now to Fig. 1~ means 190,191 are generally indicated therein~ these means being adapted to prevent opening the apparatus according to Fig. 1 other than when the bottom of the box 1 is on a horizontal substructure.
It is thus avoided that the styluses 199 fall out of their holders when the cassette is opened.
In the box 2 in Fig. 1 -there will be seen registrat-ions applied on the paper 80. Printed lines 40,~1,42; 50, 51,52; 60,61,62;70 are shown on the paper 80. These lines constitute references with respect to the accelerations and retardations to which the cassette is subjected. The indication P0 may be assumed to be a reference time mark--ing made by the means 121. The writing means A,B,C have thereby registered the application of force in the respect-ive dimension, starting -from a normal position which indi-cates the attitude of the apparatus.
As will be seen, e.g. from Fig. 3, the wire 106 can be attached to the writing means C by means of a simple clamping screw 108.
A second fork 200 is also pivotably mounted on the shaft 90. The second fork 200 includes two separate second shanks 201,202 pivotably mounted on the shaft 90, these shanks being astride the dog pin 91 and guiding pin 92. A
flap 203 is arranged on the sllank 202. The flap 203 funct-ions as a stop means and prevents the shank 201 from being swung relatively closer to the shank 202. A second spring elcment 22 is coupled between the shanks 201,202 o-f the se(ond rork 200. Thç spring 22 is wishbone-shaped and has inwardly bent end portions, which can be optionally in-serted in one of a row of recesses 122 on each o-f the shanks 201,202. It is thus possible to ~djust the turning momcnt which the spring 22 is to apply to the shanks 201, 202.
Fig. 6 illus-trates the embodiment and arrangelnent of the pendulum 31. The pendulum is accomrnodated in a space which is laterally deEined by walls 3~. The pendulum has side sur-faces ~3 adapted -for coming into superficial contact with the walls 34. The walls 34 thus serve to limit the oscillating movement of the pendulum. The pen-dulum 3~ is longitudinally defined by circular arcs with their centre at the shaft 90. The space is longitudinally defined by wall surfaces with a form corresponding to the contiguous defining surfaces of the pendulum. A clearance 32 is thereby arranged between the pendulum and the space in the longitudinal direction of the space. The clearance 32 is arranged to attain at mos-t the ma~imum permitted radial play of the bearings 81.
Fig. 7 schematically illustrates how the writing means are moved under the action of the means 7. It can be assumed that the pendulum 31 has a mass m and that the dog pin 91 is arranged at the centre of gravity of the pendulum. It can be further assumed that the springs 21,22 act in the path of the pendulum's centre of gravity.
It can be further asslimed that the oscillating angles of the pendulum are very small, so that the centre of gravity of the pendulum moves substantially linearly.
In accordance with the invention, it is prescribed that the first spring element 21 shall afford biassing the pendulum 31 towards its normal position. The bias AF suit-ably attains a value correspondil1g to 0.1 g where g relates 1 '1 to gravity. The spring constant of the spring 21 is adapt-ed such that the writing means is displaced a distance when the spring is subjected to a load of the order of magnitude F-~F ~e.g. 0.9 g). When the writing means is dis-placed to the position S1, the dog pin 90 and stop pin 92are each in contact with the respective shank 201,202 of the second fork 200. The stop flap 203 ensures that the spring 22 does not exercise any force on the pins 91,92 in this condition.
However, iE the pendulum 31 is swung out past a position corresponding to S~l, the spring 22 will also counteract such an outwardly swinging movement. The spring 22 can be adapted to provide a resistance force, together with the spring 21, for a displacement position 2 S1 which attains -Eor example 25 g, 100 g or 10 g, depending on the greatest measuring range it is desired to give the apparat-us .
If the apparatus should be given an attitude such that gravity exercises a maximum torque on the pendulum 30 about the shaft 90, the associated writing means will assume a position corresponding to S1 61. The pendulum 31 will now rest against the second spring means 22 with the force which is substantially equal to the biassing force ~F (0,1 g). When the apparatus is in this attitude, the writing means will not be displaced before an accelerat-ion force on the device 7 exceeds ~F ~0,1 g). From Fig. 1 it can be read that the apparatus has had an attitude be-tween the times To and T1 (indicated along the line 70) which can be read from the writing means A having had a normal position along the line ~0, the means B a normal position along the line 50 and the means C a normal posit-ion along the line 61. With reference to Fig. 12, the apparatus should thus have been situated with its sur-Eace M oriented in the horizontal plane and facing downwards between the times To and T1. Correspondingly, i,t will be seen that during the times T1 and T2 the apparatus has ~ ~B~

been oriented with its bottom surface l~ in the horizontal plane and facing downwards .It will be seen that orie]ltat-ion of the apparatus in space can be un~mbigously deter-mined by reading ~he positions of the registrations in S relation to the norma], or rest positions for the respect-ive writing means in relation to the corresponding lines on the paper 80.
If so desired, a further actuating means can be arranged through the wall of the box 2 9 e.g. in the vici-nity of the locking element 4, by which the drive 140 of the registering paper 80 can be started or stopped while the apparatus is in a closed condition.
When the apparatus is subjected to relatively rapid movements, the registrations will constitute an indicat-ion of the accelerations and retardations to l~hich it has been subjected. For relatively slow actions of forces, the registrations will be an indication of the speed at which the apparatus has been acted on. The graphite stylus 199 in the writing means A,B,C affords friction damping of the indicating system, and this damping is independent o-f tem-perature conditions, since the -friction of the graphite is substantially independent of temperature.
With reference to Figs. 8 and 9, it can be noted that the tracks 217 and Z18 are arranged prestressed towards each other so that the rollers 219 are in s~able contact with respective track. There is thus an easily movable connection between the arms 113 and 213, and this connect-ion is entirely without play.
With reference to Fig. 11, the paper 80 is initially wound up with play round the roller 145. When the paper coil round the roller 145 tends to obtain a peripheral speed exceeding the intended pa~er feed rate, the web begins to be wound from within into tight contact with the roller 145.
The roller 145 is driven by friction contact with the drive roller 141, which is driven by the clock-I(--controlled motor spring 140. A -feed roller 142 is pos;tive-ly driven by the roller 141, e.g. by a gear drive. A ~en-sioning roller 143 presscs the web 80 against the drive roller 142. If the diameter increase on the winding rol]er 145 causes a tensional force in the paper web, this ten-sional -force will be transferrecl via the roller 141 to the roller 142, thus conserving driving power. At the terminat-ion of the reeling operation, slip between rollers 141 and 145 can prevent the web 80 increasing speed.
The apparatus in accordance with the invention is suitably enclosed in stable cassette boxes, e.g. made from Hydronalium .
In spite of small physical dimensions, the apparatus in accordance with the invention affords a stable, easily read attitude registration and furthermore clear orce registration both for relatively small forces of vibration-al character and large forces of shock character.

Claims (10)

1. Apparatus for registering accelerations and retardations, including a basic structure (1,2) on which an inertial mass (31) is suspended by spring means (21, 22) and adapted for controlling a writing means (C) co-acting with a web (80) of registering medium adapted for running substantially transverse the direction of movement of the writing means, characterized in that the spring means (21,22) includes two spring elements, of which the first element (21) is adapted for urging the mass (31) to a normal position (60; S0) with a force (.DELTA.F) attaining a fraction of the force (F0) with which the mass maximally acts on the first spring ele-ment (21) under the action of gravity, and that the second spring element (22) is adapted to start excer-cising an elastic deformation resistance to the dis-placement of the mass when the latter is moved past a displacement position (61,62), substantially situated at a distance (S) from the normal position (60; S0) corresponding to the length (s+r) the mass can maximal-ly deform the biassed first element (21) under the action of gravity minus a length (r) corresponding to the deformation of the first spring element occurring for a loading on the first element (21) with a force of the same order of magnitude as said biassing force (.DELTA.F).

2. Apparatus as claimed in claim 1, character-ized in that the mass (31) has the form of a pendulum pivotably mounted on a shaft (90), said pendulum having a dog pin (91), in that a first fork (100) comprising two separate first shanks (101,102) pivotably mounted on the shaft (90) sits astride the dog pin (90) and a guiding pin (92), which is rigidly attached to the basic structure in a position corresponding to the neutral position of the pendulum, in that the first spring ele-ment (21) is coupled between the first shanks (101,102) to limit their swinging apart, in that a second fork (200) comprising two separate second shanks (201,202) pivotably mounted on the shaft (90) is astride the dog pin (91) and guiding pin (92), in that stop means (203) are adapted to limit the angle included between the second shanks (201,202) to a minimum valve corresponding to the distance (s), and in that the second spring element (22) is coupled between the second shanks (201,202) to limit their swinging apart.

3. Apparatus as claimed in claim 1 or 2, char-acterized in that the biassing force (.DELTA.F) attains to about 10% of the force (F) with which the mass maximally acts on the spring means under the action of gravity.

4. Apparatus as claimed in claim 2, character-ized in that the edges of the first shanks (101,102) facing towards each other are arranged to be in contact with the dog pin (91) as well as the centre pin (92) in neutral position of the pendulum, and that the dog pin (91) is preferably mounted parallel to the shaft and at the centre of gravity of the pendulum.

5. Apparatus as claimed in claim 2, cha-racterized in that the writing means (C) includes a carriage (170-176) which is guided transverse the direct-ion of movement of the web and which carries a stylus (199), adapted for being in contact with the web (80), there being an arm (103) coupled to the carriage via link means (113,106), said arm being pivotably mounted at the shaft (90) and carried by the dog pin (91).

6. Apparatus as claimed in claim 4, character-ized in that the pendulum (31) is mounted in roller bearings (81) on the shaft (90) and that abutment sur-faces are arranged on opposing sides of the pendulum in its radial direction, with a clearance (32) to the pendulum which at most attains the maximum permitted radial play in the bearings (81).

7. Apparatus as claimed in claim 2, characterized in that the second spring element (22) has a spring constant which is about 25 times as great as that of the first spring element (21).

8. Apparatus as claimed in claim 5, characterized in that the mass is movable in a direction normal to the plane of the web, that the link means includes an arm (113) carried by the dog pin arm (103), an arm (106) connected to the writing means, and a link arm (213) which is journalled for pivoting movement parallel to the direction of movement of the writing means and the mass, in that the link arm (213) and the arm (113) carried by the dog pin arm (103) are joined to each other by means of two coaxial ball bearings which are carried by the dog pin arm (103), and two parallel running tracks on the link arm (113), the running tracks being resiliently pretensioned toward each other and wherein each of the ball bearings is arranged for running against one of the tracks.

9. Apparatus as claimed in claim 1, characterized in that the driving means for the registering medium web includes a wind-ing roller, which is in frictional contact with a drive roller driven by a power source, in that the drive roller is in positive rolling contact with a feed roller which is in contact with the registering medium web, and in that a free-running tension roller is arranged to tension the web to friction contact with the drive roller.

10. Apparatus as claimed in claim 1, 2 or 4, characterized in that it also includes a second and a third inertial mass, which are arranged, made, suspended and connected to respective writing means analogous with the first mentioned mass (31) and in that the three inertial masses are adapted movable, one in each of three dimensions preferably mutually at right angles.