US2673702A

US2673702A - Instrument mounting and an element thereof

Info

Publication number: US2673702A
Application number: US251016A
Authority: US
Inventors: Harry S Pasturczak
Original assignee: Individual
Current assignee: Individual
Priority date: 1951-10-12
Filing date: 1951-10-12
Publication date: 1954-03-30
Anticipated expiration: 1971-03-30

Description

March 30, 1954 H. SPASTURCZAK 2,573,702

INSTRUMENT MOUNTING AND AN ELEMENT THEREOF Filed Oct. l2, 1951 3 Sheets-Sheet l L... ygumr Ill-IIIIIIIIINI 1N VEN TOR.

March 30, 1954 H.`s. PAsTuRczAK 2,673,702

INSTRUMENT MOUNTING AND AN ELEMENT TMEREoF Filed oct. 12, 1951 sheets-'sheet 2 36 6g /38 511 6o im 9g 70 83 2 66 65 g .110 JDO i011 106 108 85 20 76 70 102 8O i2 Til 6 132 INVENTOR.

March 30, 1954 H. s. PAsTuRczAK 2,673,702

INSTRUMENT MOUNTING AND AN ELEMENT THEREOF Filed 001;. 12, 1951 3 Sheets-Sheet 3 Sigg. f2.

INVENTOR.

Harry 5 Pazlufcjaf Patented Mar. 30, 1954 INSTRUMENT MOUNTING AND AN ELEMENT THEREOF Harry S. lasturczak, East Moline, ill.

Application October 12, 1951, Serial No. 251,016

9 Claims.

The present invention relates to instrument mountings for adiustably supporting instruments of various kinds, especially cameras and optical instruments such as telescopes, binoculars and thelike.

The invention is designed as an improvement over the instrument mounting shown and described in my prior Patent No. 2,524,473, dated October 3, 1950, for Instrument Mounting. lin this patent there is illustrated an instrument mounting o the type in which the instrument is capable of adjustment about both vertical and horizontal axes, together with means for holding or locking the instrument in any desired position oi adjustment relative to both the vertical and the horizontal axes. Selectively operable trigger-operated releasing means are provided which is capable of being set or conditioned so that, upon operation of the trigger, the locking means which holds `the instrumentagainst both horizontal and vertical swinging movements are simultaneously released to permit universal adjustment oi the instrument. Alternatively, the trigger-operated releasingr means is capable of being conditioned or set so that. the locking means which holds the instrument against panoramic swinging movement in azimuth is permanently disabled and does not come under the control of the trigger so that the latter may control only the locking means which holds the instrument against tilting movements in elevation about a horizontal axis.

The structure and functionoi the present invention is generally similar to the structure and function 0I" the inventionv shown and described in the above-mentioned patent, but in the present instance certain rennements have been incorporated which render the instrument mounting more efficient in its operation, more readily susceptible to economical manufacture and simpler to manipulate in attaining the desired function. It is therefore among the principal objects of the present invention to improve instrument. mountings of the character shown in the above patent in: various respects sol as to simplify the construction of the various parts, to improve their cooperative action, as well as to iaoilitate their manipulation when in use.

Briefly, the instrument mounting shown in the above-mentioned patent includes among other things an elbow structure having a verticalv leg anda horizontal arm and on which. the instrumentis mounted by means of suitable supporting mechanism. ,The .1 elbow is. capable oi' rotation about its vertical leg to attain horizontal swinging movement or panoramic sweep of the instrument and the supporting structure for the instrument is rotatable about the horizontal arm to attain horizontal tilting adjustment of the instrument. The elbow is split longitudinally through the middle andthe metal oi the elbow at the split edges thereof is relieved on both sides vof the base of the elbow to provide a rocking or fulcrum axis which functions,A when the split sections of the horizontal arm are brought together to spread the split sections of the vertical leg and vice-versa. When the split sections of the horizontal arm are compressed or brought together, the consequent spreading of the split sections of the vertical leg causes them to bind against the inner wall of. the tubular mounting of the elbow so that the latter is locked against .rotation about a vertical axis and so that the instrument itself is held against panoramic sweeping movements.

The structure of this patent further includes trigger-operated locking means which is normal- 'ly eiective to maintain the sections of the horizontal arm of the split elbow in a contracted or compressed condition so as to spread the sections of the vertical leg against the wall of the elbow mounting and thus lock the elbow against turning movement about the axis ofthe vertical leg. The trigger operated locking means is capable, upon operation of the trigger thereof, to release the compressional forces normally applied to the sections of the horizontal arm. so

as to relieve the binding action of the sections of the vertical leg upon the wall of the elbow mounting and permit turning movement ofthe elbow about a vertical` axis. 'Control means are provided for permanently spreading the sections oi 'the horizontal arm so as to positively contract the sections of the vertical leg and thus render the trigger operated locking means incapable of spreading them so that panoramic sweeping movements of the instrument. are available regardless of the operation of the trigger-operated locking means which, under such conditions`, is eiiective only to control the locking or releasing of the instrument against tilting Ymovements in elevation about a horizontalY axis. rIhe present invention involves an. improved form of split elbow structure, together with an improved' cooperating spreading means for effecting Yspreading of the split sections of the horizontal arm thereof wherein the operations of machining the various. parts involved are greatly simplified.

The provision of anelbow construction and f a spreading means therefor o'f the character briefly outlined above being among the principal objects of the present invention, another object thereof is to provide Such a spreading mechanism which will accomplish the functions of the earlier mechanism in a simplified manner and with less complexity of manual control.

Another object of the invention is to provide an instrument mounting of the character briefly outlined above in which the mating sections of the split elbow are inherently in themselves held against axial shifting movement along one leg of the elbow and in which the fulcrum axis is incapable of shifting.

Another object of the invention is to provide a novel method of forming split elbow constructions designed for use in connection with instrument mountings in the manner indicated briefly above.

Other objects of the invention not at this time enumerated will become readily apparent as the nature of the invention is better understood.

In the accompanying three sheets of drawings forming a part of this specification, one embodiment of the invention has been shown.

In these drawings:

Fig. 1 is a side elevational view of an instrument mounting constructed in accordance with the principles of the present invention;

Fig. 2 is a fragmentary side elevational view of the structure shown in Fig. 1 as viewed from the left hand side thereof and showing the same mounted on a tripod or similar support;

Fig. 3 is a side elevational view similar to Fig. 2 with certain parts thereof being shown in section to more clearly reveal the nature of the invention;

Fig. 4 is a sectional view taken substantially along the line 4 4 of Fig. 2;

Fig. 5 is a sectional view taken substantially along the line 5 5 of Fig. 1;

Fig. 6 is a sectional View similar to Fig. 5 with the parts shown in a different position;

Fig. '7 is a composite view including a sectional view taken substantially along line 1 1 of Fig. 5 and an end elevation of the lock control mechanism when conditioned in accordance with the disclosure of Fig. 5;

Fig. 8 is a composite view including a sectional view taken substantially along the line 8 3 of Fig. 6 and a side elevational view of the lock control mechanism when conditioned in accordance with the disclosure of Fig. 6;

Fig. 9 is an expanded end elevational view of a split elbow construction employed in connection with the present invention.

Fig. 10 shows full size views, in elevation, of the inner faces of both sections of a split elbow forming a part of my invention, the said views illustrating portions of a fractured vertical rib on each section, whereby the rib in the assembled relation of the elbow sections constitutes a fulcrum for pivotal movement of said sections.

Fig. 11 is a full size plan View of the elbow section shown in Fig. 10 arranged in the assembled relation shown in Fig. 5, the ends of the horizontal arm of the elbow being moved together to emphasize the pivotal action of the elbow sections with respect to each other; and

Fig. l2 is a view similar to Fig. 11, but illustrating the elbow sections moved to another position about their fulcrum axis.

The improved instrument mounting comprising the present invention involves in its general organization a two-piece split tting or elbow I0 which, when assembled in the IlSi/lllmtlnt mounting, includes a composite vertical leg I2, a composite horizontal arm t4 and a composite connecting elbow portion IE. The leg E2 is telescopically received and supported in a base socket member I8 in which it is retained by means of a keeper screw 20 which extends through the base and into an annular groove 22 provided near the lower end of the` leg I2. The elbow I0 is thus capable of rotational movements about the vertical axis of the socket member I8 for panoramic sweeping movements of the camera or other instrument as will be described presently. The arm I4 receives thereover a self-braking locking collar 24 on which the instrument is adjustably mounted and the locking collar is capable of tilting movements about the horizon tal axis of the arm I4, when released for such tilting movement, or of being locked to the arm I4 against tilting movement thereon in a manner and for a purpose that also will be set forth presently.

The adjustable mounting for the instrument on the locking collar assembly 24 forms no part of the present invention and reference may bc had to the above mentioned patent for a full disclosure thereof. However, for convenience of description it may be stated briefly that this mounting includes on instrument-supporting assembly 25 having a adjustable pad 25 providing a seat on which the instrument, which may be a camera (not shown), is clamped. The pad 25 provided with the usual instrument stud and thumb wheel assembly 28. The locking collar assembly 24 includes an upper offset apertured lug 32 on which the assembly 25 is adjustably mounted and to which it is adapted to be adjustably clamped by means of a clamping knob 34.

Referring now to Figs. 2, 3 and 9, the split elbow I0 comprises two separable, similar and complementary L-shaped

sections

36 and 38. The two

sections

36 and 38 are initially formed in one piece as a unit, as for example, by a die casting operation and finished to form an elbow fitting in which the two sections are maintained spaced from each other by means of a relatively thin, elongated, frangible connecting web 40 (Figs. 3 and 9) which extends vertically along two opposed edges of the leg portion I2 and transversely across the horizontal arm I4 and across the elbow portion IB. The vertical leg portion I2 is, for convenience and lightness, relieved as at 42 to provide an internal vertical bore and the arm I4 is similarly relieved as at 44 with the twlo relieved portions being separated by a channel 46 in the metal across which the frangible web 40 extends. The initially formed or cast elbow is split longitudinally along the major outside surface thereof to provide a pair of

opposed surfaces

48 and 50 which extend from the lower end of the leg I2 around the elbow portion I6 to the end of the arm I4. The split in the outer side of the initially formed or cast elbow is interrupted only by the vertically extending web 40 (see Figs. 5 and 6). The lower wall of the arm I4 is split as at 52 along a minor region diametrically opposed to the major split portion of the elbow and thus, in the initially formed or cast article, the two sections 35 and 38 thereof are maintained slightly spaced from each other with the frangible web 40 constituting the sole inter-connecting means between these two initially integral parts.

The frangible web is broken along its length and this is readily accomplished by the simple procedure of misaligning the two sections 36 and acre-voc '35 lay-.applying spreading pressure thereto sun-icient'` to fracture the webalong an 'irregular line as clearly .shown by the stippling of Fig. 3 and.E which fracture also appears iniFigs. 9, lo, il and' 12 `where the two

parts

36 and 38 are sepa- .rated from eachother. A. portionfoi thei fractured web it also appears in Fig. l.

The web It, when fractured in the manner setfcrth above, constitutes anV elongated fulcrum 'by means of which the two parts when assembled upon each. other in the instrument mountin'gr may be rocked to a slight degreev relative to each other. In the assembled structure` a resilient gasket'li may be inserted 1between the two parts 36 .and 38 at the base of' the'arm it (Figs. .3ifa'nd e) and a second .resilient gasket 5c may :extend between the opposedV faces i8 and til of the sections along the opposedfaces of theelbow portion It to limit or restrain the rocking movement between the two sections.

From the above description, it lwill be seen thatwhen the composite arm ifi is compressed `s'oafs to roel: the sections 3h and 38 about the fulcrum axis of the `web 4G and bring the outer ends of the arms toward each other as shown Vin Figs. 5, 7, l1 and 12, there will .bea widening of the distance between the-opposed surfaces lli! and 5l! `of the` composite leg l2, thus in effect, increasing the diameter of the composite leg l2 by a spreading action so that the outside surfaces ofthe twov parts 35 and Se will bear against the inner surface `of the base socket i3 and bind vthe leg: t2 in the socket ifsto prevent rotational movement of the elbow structure i@ as a whole about a vertical axis. Upon release of compressional force on the composite arm ill, the resilient gasket 54 in a measure serves as a cushion buffer between the two sections 3S and 3S of the arm so as to hold them in proper position to facilitate turning movement oi the elbow about the vertical axis of the leg i2.

Inasmuch as the two sections 3e and til of the split elbow in the regions of the leg E2.' are closely encased `within the vertically extending cylindrical confines of the base socket, there is little opportunity for the opposed contiguous fracture areas of the web 4c to become separated to adegree sufficient to permit longitudinal shifting movement of one section relative to the other.

The opposed fractured areas are precisely, and

even the microscopically small ridges of the one extend into the valleys of the other and vice versa and the only relative movement between these two opposed surfaces is, an extremely limited rockingY movement.

By the same token, the so-called spreading orA contracting movements of the sections of the composite split leg i2 is the result. of such tilting or rocking movement between the se"- tions on the fulcrurn axis of the web wherein the surfaces 138 and 5@ recede from or approach each other respectively. The spreading and contractingl movements ofthe sections of the split arm i4, however, is of a diierent nature. In this instance, since the-axis of the fractured web 4l! is perpendicular to the axis of the cornposite split arm ifi, rocking of the two sections 35 and 38 will effect equal recession and approach of the surfaces i3 and 5@ and of the opposed surfaces along the split portion E2.

Referring now to Figs. l and 4, the locking collar 24 includes. a body portion 6D provided with a transverse opening 62 therein through which the composite split arm icl of the elbowv it extends and onwhieh arm the lockingV collar vis Vi5 supported for angular tilting movement about a horizontal axis. The body I6 includes a yield'- able friction band @fl which issplit medially and circumferentially therearound as at 65 (Fig. 2) and which encompass the arm ill and is movable into and out of clamping engagement with the latter. The straps or sections of the split band S45' are resilient and are normally sprung outwardly so as to relieve their gripping action Vonthe split arm i i and they are capable of being forced into gripping engagement with the arm in the manner of a brake band by means of a pair of attachment lugs t@ which are operatively connected through a train of mechanism about to be described to acompression spring 68 associated with an operating handle or pistol grip assembly le.

The pistol grip assembly lil includes a barrel portion l2, the forward end of which projects through a sleeve or thrust bushing lli yieldingly and frictionally held in an offset apertured lug 'iii provided on the body portion of the locking assembly 2e. The barrel 'i2 projects into the casing 'il of the pistol grip assembly and is provided with a clearance slot 'i8 through which there extends the upper end of a trigger member 33 which. is pivcted as at di. to the casing 11 and which depends from the latter. The casing 'il is provided with a trigger handle Bil in which the trigger Trl is guided. The sleeve lll and barrel i2 are secured together against relative turnmcvf-rnent by means of a pair of screws 85 which p through the sleeve and into the wall of the el. The body portion 'il including the handle together with the barrel i2 are capable ci lateral swinging movement about the axis of the barrel to accommodate the natural position ci the wrist and hand during operation of the instrument mounting.

The pressure spring te is disposed within the barrel 12' adjacent its rear end and pressure eX- erted by 'the spring is adapted to be applied to the clamping bands t!! of the locking collar 2d through the medium of a sectional thrust rod including a rear rotatable section 38 and a front non-rotatable section 53, both sections being disposed within the barrel 'i2 in end-to-end relationship. The non-rotatable section gli is provided with an ear which projects upwardly through a slot provided in the barrel 'i2 in the upper regions thereof and which slot is of fairly large circumferential extent, in order to give a wide angle ci swinging movement to the pistol grip handle Ei. The rear rotatable rod section 5.23 is provided with a slot 96 in register with the slotl and through which the trigger member 8! extends. The rear end of the rotatable rod section it slotted as at and a guide pin lli!) carried by the barrel 'l2 projects through the slot QS so as to connect the barrel and rod section for turning movement in unison while still permitting relative sliding movement of the rodsection within the barrel. The trigger member 331s adapted to bear at mi against one end of the slot in the rod section @il and the forward movement of the trigger member 85 and consequently ofthe rod section 8S, is limitedk by a stop surface iii@ provided on the body 'El'.

effective length of the non-rotatable rod section @El is capable of being varied by means of a pin ich which extends through a bore itt pro'- vided in the rod section E@ and which has its rear end projecting beyo, *l the end of the rod section si! and bearing ag inst the end' of the rods'ec'- tion 33. V'lhe forward end of thev pin` Illia'r i's threadably received in the forward end of the rod section 90 and an adjusting knob I I6 secured to the extreme forward end of the pin |66 is provided so that the pin may be shifted in one direc- -tion or the other through the section 36 to increase or decrease its effective length and thus determine the throw of the friction bands 64. The trigger member 83 is normally held against the rear end of the slot 33 by means of a spring pressed plunger |I2 disposed within a bore provided in the rotatable rod section 88, The rear end of the barrel I2 threadably receives an adjusting plug |54 by means of which the compression oi the spring 68 may be varied to in turn vary the pressure applied to the friction bands -Y From the above description it will be seen that when no pressure is applied to the trigger member 86 the spring 68, acting through the two

rod sections

38 and 96, will apply full pressure to the friction bands 64 tending to contract the same on the horizontal arm I4 of the split elbow IB, thereby not only holding the locking collar or brake 24 against turning movement about the horizontal axis of the arm, but also compressing the split end of the arm i4 and spreading the split leg I2 thereof in the manner previously described to lock the split elbow against turning movement about a vertical axis. The instrument support or pad 26 is thus locked against swinging movement about either a vertical or horizontal axis. Upon depression of the trigger member 33 the rotatable rod section 83 will be moved to the left as viewed in Fig. 4, thereby compressing the spring 68 and allowing the rod section 96 to follow the movement of the rod section 33 to release the pressure on the friction bands 6d and permit the

split sections

36 and 38 of the composite arm I4 to move away from each other. Pressure of the split sections of the leg I2 against the inner wall surface of the base socket I8 is thus relieved so that the split elbow IE) is capable of turning movement within the base socket. At the same time the relieving of pressure by the friction bands 64 on the arm I4 permits the locking collar 24 to be swung about the horizontal axis of the arm to tilt the instrument support or pad 26 in a fore and aft direction.

The instrument mounting of the present invention is capable of two main types of control.

The instrument support or pad 26 may be locked in a xed position against swinging movement in elevation about the horizontal axis of the arm I4 in a fore and aft direction, or it may be locked against panoramic swinging movement about the vertical axis of the leg |2 and the instrument Support may be released for both types of movement simultaneously upon depression of the trigger member 8D. Alternatively, the control means may be so conditioned that release of the trigger member 36 is incapable of locking the instrument support 26 against panoramic swinging movement and is capable only of locking the support 26 against fore and aft swinging movement.

The control means for effecting these two types of locking action is best illustrated in Figs. 1 and 5 to 8 inclusive. As shown in these views, a cap member |22 is telescopically received over the end of the split arm I4 and is provided with a centrally disposed wedge cam member |24 having a cylindrical surface |26 somewhat greater than a half-cylinder and having a flat surface |28 extending across the opposed ends of the cylindrical surface |26. The ends of the cylindrical surface |26 are relieved as at |30 to 8 provide surfaces which are less eccentric with respect to the axis of the cam I 24 than is the eccentricity of the cylindrical surface |26. When the cap member |22 is in position on the end of the arm I4, the cam member |24 is adapted to project into the end of the bore 44 and, with the cam assuming the position shown in Fig. '7, the cam is nested within the concave inner surface of the bore 44 so that sufficient clearance is provided whereby the two

sections

36 and 38 of the arm I4 may be rocked about the axis of the fulcrum 40 and thus contracted or expanded at will.

When the cam |24 assumes the position shown in Fig. 8, wherein it is at right angles to the position formerly described in connection with Fig. 7, it is nested within both concavities of the two

sections

36 and 38 and therefore it serves to maintain these sections separated in their expanded positions. With the cam |24 in this latter position, the friction bands 64 are incapable of compressing the split arm I4 and therefore the two

sections

36 and 38 are maintained in such a position that the leg I2 of the elbow I0 is contracted, thus allowing panoramic swinging movement of the instrument support.

An adjusting screw I3I extends through the wall of the section 36, is threaded therein, and has a rounded end |33 capable of projecting into the bore 44 and into the path of movement of the surface of the cam |24. The position of the screw I3| may be adjusted to vary the spread of the

sections

36 and 38 of the split arm I4 when the cam |24 assumes the position shown in Fig. 8. Stated in other words, the adjusting screw IBI serves to vary the effective diameter of the bore 44.

The cam |24 is centrally secured to the inside of the cap member |22 by means of a screw |32 which extends through the cap centrally thereof and is threadedly received in the cam |24. The screw |32 has secured thereto an operating lever |34 which is provided with a spring-pressed detent |36 designed for cooperation with a pair of depressions |31 provided on the outer surface of the cap and by means of which the lever |34, and consequently of the cam |24, may be locked in either of two selected positions. Suitable labeling or designations of the position of the lever |34 may be inscribed on the outer surface of the cap |22 and, as shown in Fig. 7, when the lever |34 is in the vertical position labelled Lock, the cam |24 assumes the position shown wherein freedom of rocking movement between the two

sections

36 and 38 is made possible, so that when pressure is applied by the friction bands 64 from the coil spring 68 tending to contract the sections of the split arm I4, the sections of the split leg I2 are spread apart thus applying pressure to the inner wall of the base socket |8 and preventing panoramic swinging movement of the instrument support 26. When the lever |34 assumes the horizontal position shown in Fig. 8 labelled Pan, the cam |24 assumes the position shown wherein the two

sections

36 and 38 are spread apart and are incapable of being moved toward each other. In this position of the cam, the two sections of the leg I2 are positively contracted and no pressure is brought to bear on the inner surface of the base socket I8 so that panoramic swinging movement of the instrument support 26 is at all times available.

The cap I 22 is adapted to be securely held in its position over the end of the arm I4 by means of a locking pin l-38 having a knurled head M0 Yand which extends through an opening |42 in the cap |22 and is threadedly received in the composite arm I4.

I claim:

1. In an instrument mounting, a split elbow structure having a vertical leg adapted to be telescopically received within a vertically extending bore of a base socket, a horizontal arm adapted to receive thereover and support thereon a locking sleeve of an instrument support, and a connecting curved elbow section, said elbow structure being split lengthwise and substantially centrally thereof (see Figs. l, 5, '7, lo, l1 and l2) and providing two spaced apart complementary half-sections, and means interposed between said sections at spaced points on a straight line extending lengthwise of the vertical leg of said elbow structure and providing a fulcrum axis whereby said sections may be rocked relative to each other about said fulcrum axis whereby movement of the complementary sections of the armtcward each other will cause movement of portions of the complementary sections of the leg away from each other and thereby adapted to force the latter sections into frictional contact `with the inner wall of said vertically eX- tending bore of the base socket.

2..In an instrument mounting, a split elbow structure having a vertical leg adapted to be telescopically received within a vertically extending borc of a base socket, a horizontal arm adapted toreceive thereover and support thereon a locking sleeve of an instrument support, and `a connecting curved elbow section, said elbow structure being split lengthwise and substantially centrally `thereof and providing two spaced apart complementary half-sections, and a relativelyf thin web having at least a portion thereof formed on one of said sections and bearing against the other section and extending along a straight line adjacent and parallel to the inner edges of the leg portions of said elbow structure and providing a fulcrum axis about which said sections may be rocked throughout a limited extent relative to each other.

3. A split elbow structure ior instrument mountings of the character described having an outwardly extending leg at one end thereof, an outwardly extending arm at the other end thereof, and an interconnecting curved elbow portion medially thereof, said elbow structure being split lengthwise and substantially centrally thereoic to provide two spaced apart complementary half-sections, and a relatively thin web of straight line configuration extending along the region or the inner edges of the composite leg sections between said sections and providing a fulcrum axis about which the sections may be tilted relative to each other. f

Il. A split elbow struct-ure for instrument mountings ci the character described having a leg and an arm extending at angles to each other, and an interconnecting curved elboiv section, said elbow structure being split lengthwise and substantially centrally thereof to provide spaced apart complementary half-sections, and a relatively thin web of straight line conguration extending along the region of the inner edges of the composite leg sections and transversely across the elbow section and providing a fulcrum axis about which said sections may be rocked relative to each other.

5. A split elbow structure for instrument mountings of the character described having a I0 leg and an arm extending VatY angles to Ieach other, and an interconnecting curved elbow section, Vsaid elbow structure being split lengthwise and substantially `centrally thereof to `provide complementary half-sections, and a relatively thin linear yfiange of straight line coniiguration formed on each of' said sections and extending along the respective inner edge of the leg portion thereof and transversely across the elbow section thereof to hold said complementary sections in spaced relation to each other, said flanges beingin direct opposition and edge-toedge contact -with each other and providing a fulcrurn` axis labout which the sections may be tiltedrelativeto each other.

6. A split elbow structure for instrument mou-ntings ofV the ycharacter described having a leg `and an arm extendingat right angles to each other, and an interconnecting curved elbow section, said elbow structure being split longitudinally and substantially centrally'to provide complementary half-sections, and a relatively thin `web of straight-line configuration extending across the region ofth'e inner edges of the composite leg sections and transversely across the elbow section and axis of the arm section, said web having a portion 'thereof formed on one of said `secti'onsand another portion thereof formed on the other-section with tl'ie'medial regions of the web being fractured along its lentire length to provide irregular mating surfaces which constitute an iniinite series of available fulcrum points arranged generallyin alignment for rockingV movement of the two 'sections' relative to each other.

'i'. An instrument mountingcomprising a base socket member having a vertical cylindrical wall, a split elbow structure having 'a vertical leg adapted to be telescopically 'received within said socket and a horizontal Varm adaptedto receive thereover and'supportithereon a locking sleeve of an instrrmentV support, said elbow Vstructure being split lengthwisearrd substantially v'centrally thereof and providing two complementary halfsections, said sections being provided on their inner faces with a iulcrum bearing whereby rocking movement of the sections on each other to move the complementary sections of the horizontal arm toward each other and force the complementary sections of the vertical leg into frictional holding engagement with the cylindrical wall of said socket, the complementary sec-tions or said horizontal arm being recessed internally to provide a substantially cylindrical bore within the composite arm, a cam telescopically received in said bore and having a generally semi-cylindrical outer surface designed for wedging engagement with the opposed walls of said bore, said cam when in one position of adjustment having its semi-cylindrical surface in spreading engagement with the opposed walls of said complementary sections of the horizontal arm, and when in another position of adjustment having its semi-cylindrical surface substantially wholly contained within one wall of said bore to relieve the pressure applied to said walls and permit rocking movement of the sections relative to eeach other, and manual means for moving said cam to either of said positions of adjustment.

8. An instrument mounting comprising a base socket member having a vertical cylindrical wall, a split elbow structure having a vertical leg adapted to be telescopically received within said socket and a horizontal arm adapted to receive thereover and support thereon a locking sleeve of an instrument support, said elbow structure being split lengthwise and substantially centrally thereof and providing two complementary halfsections, said sections being provided on their inner faces with a fulcrum bearing whereby rockingmovement of the sections on each other to move the complementary sections of the horizontal arm toward each other and force the complementary sections of the vertical leg into frictional holding engagement with the cylindrical wall of said socket, the complementary sections of said horizontal arm being recessed internally to provide a substantially cylindrical bore within the composite arm, a cup-shaped cap member telescopically receivable over the end of said arm, a cam mounted for rotation on said cap member centrally thereof and receivable on said bore when said cap member is in position on the arm, said cam having a generally cylindrical outer surface designed for wedging engagement with the opposed walls of said bore, said cam when in one position of its adjustment for its semicylindrical wall in spreading engagement with the opposed walls of said complementary sections of the horizontal arm, and when in another position of adjustment beingsubstantially wholly contained within one wall of said bore to relieve the pressure applied to said walls and permit rocking movement of the sections relative to each other, an operating finger secured to said cam and projecting through the wall of said cap member and movable with the cam between two positions of adjustment and detent means for holding said operating finger in either position of adjustment.

9. An instrument mounting comprising a base socket member having a vertical cylindrical wall, a split elbow structure having a vertical leg adapted to be telescopically received within said socket and a horizontal arm adapted to receive thereover and support thereon a locking sleeve of an instrument support, said elbow structure being l2 split lengthwise and substantially centrally thereof and providing two complementary half-sections, said sections being provided on their inner faces with a fulcrum bearing whereby rocking movement of the sections on each other to move the complementary sections of the horizontal arm toward each other and force the complementary sections of the vertical leg into frictional holding engagement with the cylindrical wall of said socket, the complementary sections of said horizontal arm being recessed internally to provide a substantially cylindrical bore within the composite arm, a cup-shaped cap member telescopically receivable over the forward end of said arm and having a cylindrical flange encompassing said arm for limiting the spreading movements of the complementary sections thereof, a cam mounted for rotation centrally within said cap member and projecting into said bore, said cam having a generally semi-cylindrical outer surface designed for wedging engagement with the opposed walls of said bore, said cam when in one position of adjustment having its semicylindrical wall in spreading engagement with the opposed walls of said complementary sections of the horizontal arm, and when in another position o adjustment having its semicylindrical surface substantially wholly contained within one wall of said bore to relieve the pressure applied to said walls and permit rocking movement of the sections relative to each other, means extending through said cap member for moving said cam to either of its two positions of adjustment, and means for securing said cap member to one of the complementary sections of said arms.

HARRY S. PASTURCZAK.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,424,499 Pasturczak July 22, 1947 2,524,473 Pasturczak Oct. 3, 1950