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US3394977A - Variable width slit operating mechanism - Google Patents

Variable width slit operating mechanism Download PDF

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Publication number
US3394977A
US3394977A US345523A US34552364A US3394977A US 3394977 A US3394977 A US 3394977A US 345523 A US345523 A US 345523A US 34552364 A US34552364 A US 34552364A US 3394977 A US3394977 A US 3394977A
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US
United States
Prior art keywords
slit
slit defining
members
movable
slits
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US345523A
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English (en)
Inventor
Stiff Geoffrey Malcolm
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Commonwealth Scientific and Industrial Research Organization CSIRO
Original Assignee
Commonwealth Scientific and Industrial Research Organization CSIRO
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from AU27496/63A external-priority patent/AU269391B2/en
Application filed by Commonwealth Scientific and Industrial Research Organization CSIRO filed Critical Commonwealth Scientific and Industrial Research Organization CSIRO
Application granted granted Critical
Publication of US3394977A publication Critical patent/US3394977A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • G—PHYSICS
    • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
    • G21K—TECHNIQUES FOR HANDLING PARTICLES OR IONISING RADIATION NOT OTHERWISE PROVIDED FOR; IRRADIATION DEVICES; GAMMA RAY OR X-RAY MICROSCOPES
    • G21K1/00—Arrangements for handling particles or ionising radiation, e.g. focusing or moderating
    • G21K1/02—Arrangements for handling particles or ionising radiation, e.g. focusing or moderating using diaphragms, collimators
    • G21K1/04—Arrangements for handling particles or ionising radiation, e.g. focusing or moderating using diaphragms, collimators using variable diaphragms, shutters, choppers
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
    • G01J3/02—Details
    • G01J3/04—Slit arrangements slit adjustment
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J49/00—Particle spectrometers or separator tubes
    • H01J49/02—Details
    • H01J49/025—Detectors specially adapted to particle spectrometers

Definitions

  • the movable slit defining member is controlled by an operating arm and caused to move in a direction parallel to the longitudinal dimension of the slit, which in turn flexes the strips causing changes in their effective length such that the movable slit defining member has a component of motion transverse to the longitudinal direction of the slit.
  • This invention relates to variable width slit operating mechanisms, and especially to such mechanisms which are normally associated with slits for optical instruments and instruments employed for the determination and measurement of absorption and emission spectra, mass spectra and the like.
  • Slits of the type referred to above are usually bounded by adjustable slit defining members, which normally take the form of two accurately parallel, opposed knife edges, one or both of which can be moved relatively to the other so as to vary the separation distance between them.
  • adjustable slit defining members In conventional variable slit operating mechanisms the movable slit defining member is usually mounted on guide rails and is actuated by a micrometer screw. Roller mounted slit defining members and pivoted linkages are also sometimes employed. Such mechanisms generally suffer from the phenomena of lost movement, backlash and the so-called stick-slip motion, which are usually associated with screw-threaded mechanisms.
  • a further object of the invention is to provide a mechanism to controllably vary the widths of two slits in uriison.
  • a mechanism for controllably varying the width of a slit comprising a base frame, a fixed slit defining member secured on the base frame, a movable slit defining member supported from the base frame and in the same plane as the fixed slit defining member by means of two parallel, resiliently flexible arms, and operating means arranged to displace the movable slit defining member in the plane of the said slit defining members in a direction substantially parallel to the longitudinal dimension of the slit, characterised in that said displacement causes both supporting arms to be flexed, whereby the changes in the effective lengths of the arms so produced cause the movable slit defining member to be subjected to a motion in the same plane having a component in a direction transverse to the longitudinal dimension of the slit.
  • slit defining members there are two pairs of slit defining members and a common operating means which is adapted to vary the widths of both slits.
  • the supporting arms of the two movable slit defining members are equal in length, whereby the widths of the two slits are varied equally on flexure of said arms.
  • FIGURE 1 is a schematic diagram of the optical system of a monochromator, showing a typical use of a double slit;
  • FIGURE 2 is a perspective view from the front of the double slit mechanism when fully assembled (i.e. wholly enclosed within its casing);
  • FIGURE 3 is a plan view of the double slit mechanism with the front cover removed, shown in the position where both slits are closed;
  • FIGURE 4 is a view similar to that of FIGURE 3, but shown in the position where both slits are open;
  • FIGURE 5 is a cross-section along line 5-5 in FIG- URE 3;
  • FIGURE 6 is a cross-section along line 66 in FIG- URE 3;
  • FIGURE 7 is a cross-section along line 7-7 in FIG- URE 4;
  • FIGURE 8 is a cross-section along line 8-8 in FIG- URE 4;
  • FIGURE 9 is a perspective view of the two movable slit defining members and their associated support arms and operating or flexure strip, which form a unitary structure;
  • FIGURE 10 is an enlarged detail showing the portion of the actuating sleeve carrying the roller which brings about the flexure of the supporting arms.
  • the double slit operating mechanism is mounted on a circular baseplate 11, which has a raised flange 12 around its perimeter.
  • the flange 12 is provided with two diametrically opposed shoulders 13, 14, to each of which a slit defining knife blade 15, 16 is secured by means of screws which pass through elongated slots in the knife blade, thus permitting a limited degree of adjustment thereof relative to their supports 13, 14.
  • These knife blades 15, 16 constitute the fixed slit defining members of each slit.
  • the movable slit defining members are also constituted by knife blades 17, 18 which are attached to a rectangular auxiliary frame (shown in FIGURE 9), which is itself mounted on the base plate 11 within the confines of the peripheral flange 12.
  • the auxiliary frame is made up of two rigid metal support bars 19, 20, the ends of which are connected together by means of two relatively thin, flat spring members 21, 22 of a resilient metal, suchas Phosphor bronze.
  • the spring members 21, 22 are rigidly attached to the bars 19, 20, being housed or set in suitable slots at the places indicated by reference 25 and secured in position there by soldering.
  • the bars 19, 20 and spring members 21, 22 together form a substantially rectangular, open, box-like frame.
  • Each spring member is rigidly clamped at its mid-portion 26 to the vertical face of one of a pair of diametrically opposed pillars 27, 28 which are integral with the peripheral flange 12, whereby the auxiliary frame is suspended so that the upper faces of the bars 19, 20, are coplanar with the. face of the peripheral flange 12, and the lower faces of the bars 19, 20 are a small distance above the surface of the base plate 11.
  • each movable slit defining member abuts against its corresponding fixed slit defining member 15, 16, whereby the two slits of the instrument are closed. This is the position shown in FIGURE 3 of the drawings.
  • a third spring member 29 joins the mid-points of the two support bars 19, 20, and is again rigidly attached to each bar in the same manner as that described above.
  • An operating arm 30 is pivotally mounted at one of its ends on a vertical axis 31 which is located near the perimeter of the base plate 11. The arm 30 extends through a slot 32 in the support bar 20 into the region 33 bounded by the support bars 19, 20 and the spring members 22, 29. The portion of the arm 30 lying in the region 33 adjacent the spring member 22 has an arcuate outline 34 which is convex towards the spring member 22.
  • the arm 30 is connected to the spring member 29 by means of a straight, rigid link 35. Both ends of the link 35 are provided with needle points, which are adapted to engage a mating socket 36 in the operating arm 30 and a locating aperture 37 in the spring member 29.
  • the auxiliary frame is not perfectly rectangular, when the mechanism is in the unoperated condition, i.e. when the slits are closed. It is therefore preferable that the length of link 35 is increased so that, when the slits are closed, the ends of the spring members 21 and 22 are displaced a small distance (of the order of from the perfectly rectangular position.
  • An actuating ring or sleeve 38 surrounds the flange 12 of the base-plate 11, and is freely rotatable relatively thereto.
  • the ring 38 is provided with an inwardly projecting arm 39, which is substantially parallel to the base plate and carries at its end, on a vertically disposed shaft 40, a small roller 41, which runs on ball bearings and is adapted to engage the outer arcuate or cammed edge 34 of the operating arm 30.
  • the cammed outline 34 of the operating arm 30 and the disposition of the roller 41 are so chosen that, as the actuating ring 38 is rotated relatively to the base plate 11, the roller 41 displaces the operating arm 30 in such a way that the link 35 is moved by the arm substantially in a straight line which is the longitudinal axis of the link.
  • the actuating ring 38 is provided with a peg or abutment 42 to limit the extent of the rotation of the ring.
  • a calibrated scale 43 is marked on the outer surface of the ring 38 and the flanged base plate 11, to indicate the size of the slit openings for any particular angular position of the ring, and it will be readily seen that the shape of the operating arm and its disposition relative to the roller 41 can be modified to provide a large number of different relationships between the angle of rotation of the ring and the size of the slit openings.
  • a front cover plate 44 is provided for the instrument, which ensures that dust and other impurities do not get into the mechanism.
  • the cover has two apertures 45, 46 corresponding to the location of the slits, and is attachable to the base plate 11 by means of screws 47 which engage locating bosses 48, the cover being spaced from the bosses 48 by spacers 49.
  • both slits will open and close in complete synchronism.
  • the amount of movement of each slit will be equal to that of the other, provided the spring members 21 and 22 flex equally, i.e., are of the same material and of equal dimensions.
  • Slit opening mechanisms according to the present invention have a number of important advantages over presently known and used apparatus of this type.
  • the movable slit defining members move for a considerable distance in a direction generally parallel to the longitudinal dimension of the slit, for a quite small transverse movement, i.e. transverse to the longitudinal dimension of the slit (in the case of the instrument described above, the ratio between these two movements is approximately 8:1). This enables very accurate adjustment of the slit widths to be obtained.
  • the motion of the movable slit defining members does not suffer from the effects of stick-slip motion and backlash which are always a source of worry with mechanisms involving screwthreaded movements, pivoted linkages or roller mounted slit defining members.
  • the spring members are flexed well within the elastic deformation range and, although the relationship between the lateral and longitudinal motion of the movable slit defining members is not linear, this relationship can be easily calibrated and is accurately reproduced whenever the spring members are flexed (at least until metal fatigue sets in).
  • a mechanism for controllably varying the width of a slit comprising a base frame, a fixed slit defining member integral with the base frame, a movable slit defining member parallel to said fixed slit defining member supported from the base frame and in the same plane as the fixed slit defining member by means of two parallel, resiliently flexible arms, and operating means adapted to displace the movable slit defining member in the plane of the said slit defining members and in a direction substantially parallel to the longitudinal dimension of the slit such that said displacement causes both supporting arms to be flexed, whereby the changes in the effective lengths of the arms so produced cause the movable slit defining member to be subjected to a motion in the said plane having a component in a direction transverse to the longitudinal dimension of the slit.
  • a mechanism for controllabl-y varying the widths of two slits in unison comprising a base frame, two fixed slit defining members integral with the base frame, two movable slit defining members each parallel to the respective fixed slit defining members each supported from the base frame in the same plane as the respective fixed slit defining members by means of two parallel, resiliently flexible arms, and located adjacent to the corresponding fixed slit defining members, and operating means adapted to displace each of the movable slit defining members in the plane of the said slit defining members and-in a direction substantially parallel to the longitudinal dimension of each slit such that said displacement causes both supported arms associated with each movable slit defining member to be flexed, whereby the changes in the effective lengths of the arms so produced cause each movable slit defining member to be subjected to a motion in the said plane having a component in a direction transverse to the longitudinal dimension of the respective slit.
  • a mechanism for controllably varying the widths of two slits in unison and by equal amounts comprising a base frame, two fixed slit defining members integral with the base frame, two movable slit defining members each parallel to the respective fixed slit defining members each supported from the base frame and in the same plane as the respective fixed slit defining members by means of two parallel, resiliently flexible arms and located adjacent to the corresponding fixed slit defining members, said supporting arms being equal in length and of the same modulus of elasticity, and operating means adapted to displace each of the movable slit defining members in the plane of the said slit defining members and in a direction substantially parallel to the longitudinal dimension of each slit such that said displacement causes both supporting arms associated with each movable slit defining member to be flexed, whereby the changes in the effective lengths of the arms so produced cause each movable slit defining member to be subjected to a motion in the said plane having an equal component in a
  • a mechanism for controllably varying the widths of two slits in unison and by equal amounts comprising a base frame, two fixed slit defining members integral with the base frame, two movable slit defining members each parallel to the respective fixed slit defining members each supported from the base frame and in the same plane as the respective fixed slit defining members by means of two parallel, resiliently flexible arms and located adjacent to the corresponding fixed slit defining members, said supporting arms being equal in length and of the same ;modulus of elasticity, and operating means including a lever pivoted on the base frame and being adapted, on being turned about its pivot axis, to transmit a deflecting force to the supporting arms, said lever having a cammed edge which is engaged by a manually actuable cam follower, the position of which relative to said lever can be varied, whereby the angular disposition of said lever causes a deflecting force to be exerted by it on said supporting members, thereby to displace each of the mov.
  • each movable slit defining member in the plane of the said slit defining members and in a direction substantially parallel to the longitudinal dimension of each slit such that said displacement causes both supported arms associated with each movable slit defining member to be flexed, whereby the changes in the effective lengths of the arms so produced cause each movable slit defining member to be subjected to a motion in the said plane having an equal cornponent in a direction transverse to the longitudinal dimension of the respective slit.
  • each of the movable slit defining members is mounted on a rigid bar which is secured to the ends of the respective supporting arms, the midpoints of the two bars beingconnected by a flexible metal strip which is engaged at its midpoint by one end of a perpendicularly disposed rigid link, the other end of which is acted on by said pivoted lever, whereby rotation of said lever about its pivot point causes a deflecting force to be transmitted to the flexible strip, causing in turn flexure of the supporting arms.

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  • Physics & Mathematics (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • High Energy & Nuclear Physics (AREA)
  • General Physics & Mathematics (AREA)
  • Treatment Of Fiber Materials (AREA)
  • Particle Accelerators (AREA)
  • Shaping Of Tube Ends By Bending Or Straightening (AREA)
  • Mounting And Adjusting Of Optical Elements (AREA)
US345523A 1963-02-18 1964-02-17 Variable width slit operating mechanism Expired - Lifetime US3394977A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
AU27496/63A AU269391B2 (en) 1963-02-18 Improvements in or relating to variable width optical slit operating mechanisms

Publications (1)

Publication Number Publication Date
US3394977A true US3394977A (en) 1968-07-30

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ID=3715771

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Application Number Title Priority Date Filing Date
US345523A Expired - Lifetime US3394977A (en) 1963-02-18 1964-02-17 Variable width slit operating mechanism

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US (1) US3394977A (de)
DE (1) DE1210207B (de)
FR (1) FR1387514A (de)
GB (1) GB1010518A (de)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3663097A (en) * 1970-02-27 1972-05-16 Beckman Instruments Inc Resilient mounting structure for moving at least two optical elements in precise optical alignment
US3717401A (en) * 1969-10-23 1973-02-20 Atomic Energy Authority Uk Adjustable width-slit mechanism

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3098408A (en) * 1959-02-11 1963-07-23 Applied Physics Corp Double folded-zeta-configuration monochromator
US3242796A (en) * 1962-04-09 1966-03-29 Beckman Instruments Inc Slit control apparatus

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1053213B (de) * 1953-12-05 1959-03-19 Zeiss Carl Fa Veraenderbare Spaltblende, insbesondere fuer optische Geraete
US2987958A (en) * 1957-07-19 1961-06-13 Perkin Elmer Corp Optical slit mechanism
DE1122285B (de) * 1960-11-22 1962-01-18 Bodenseewerk Perkin Elmer Co Vorrichtung zum Verstellen von Spalten bei optischen Geraeten

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3098408A (en) * 1959-02-11 1963-07-23 Applied Physics Corp Double folded-zeta-configuration monochromator
US3242796A (en) * 1962-04-09 1966-03-29 Beckman Instruments Inc Slit control apparatus

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3717401A (en) * 1969-10-23 1973-02-20 Atomic Energy Authority Uk Adjustable width-slit mechanism
US3663097A (en) * 1970-02-27 1972-05-16 Beckman Instruments Inc Resilient mounting structure for moving at least two optical elements in precise optical alignment

Also Published As

Publication number Publication date
FR1387514A (fr) 1965-01-29
DE1210207B (de) 1966-02-03
GB1010518A (en) 1965-11-17

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