US2129898A - Microphone boom - Google Patents

Description

Sept. 13, 1938. A. G. WRIGHT MICROPHONE BOOM Filed Oct. 2, 1936 2 Sheets-Sheet 1 G .Y R M O MPO E Vfl M m P 8- A. G. WRIGHT 2,129,898

MICROPHONE BOOM Filed Oct. 2, 1936 2 Sheets-Sheet 2 II I I 0,2

my 1 lp mm '14 Fig. 6

V INVENTOR 37 BY ArtZur G. Wright Fig. 8.

Patented Sept. 13, 1938 UNITED STATES PATENT. OFFICE MICROPHONE BOOM ration, Los New York Angeles, Cali!., a corporation of Application October 2, 1936, Serial No. 103,715

9 Claims.

This invention relates to extensible microphone booms and deals with a, liquid operated boom.

The boom to be hereinafter described has been developed to meet the requirements of motion picture studio needs, but it will become evident as the description proceeds that it may find usefulness in other fields, such as broadcasting stations, or any other occasion where an extensible boom may be needed.

The principal object of this invention is to provide an extensible boom wherein the means for extending the boom comprises a liquid medium.

Another object is toreduce the noise common to the operation of the ordinary boom.

Still another object is to combine the counterbalancing weight necessary in booms of this nature with the means for actuating the liquid in extending the boom.

A further object is to provide an extensible boom wherein the bulk of the external equipment common to the ordinary boom is either eliminated or concealed. In this respect, it is common knowledge that the ordinary boom comprises cables, pulleys, counter-balancing weights,

5 etc., as external equipment. In my invention, I

eliminate the bulk of these and operate the extensible part of the boom by means of a noncompressible fluid, thus providing a positive action and avoiding lost motion due to cable slack.

A still further object is to provide an extensible boom characterized by workmanlike appearance, lightness, durability, and one wherein the cost of maintenance will be extremely low.

Other objects and advantages will appear as 5 the description proceeds in conjunction with the drawings in which:

Figure l is aside elevation of my boom complete, showing it partly extended with the supporting stand broken away. I v 40 Figure 2 is a longitudinal section slightly enlarged of the working parts of the boom.

Figure 3 is a cross section taken on line l3 of Flgure 2. v w

v Figure 4 is a cross section taken on line 4-4 45 of Figure 2.

Figure 5 is a cross section taken on line 5-5 of Figure 2.

Figure 6 is an enlarged section of the piston, showing the manner in which the piston isat- 50 tached to the operating mechanism and the counter-balancing weight.

Figure 'l is an enlarged section of the piston'on the extensible part of the boom, showing the manner in which the piston is attached to the g5 extensible rod.

Figure 8 shows a part of the rack with the connection to the piston gland.

Figure 9 is a longitudinal section slightly enlarged, showing the outer end of the boom and is a continuation of Figure 2. 5

Referring to the drawings and particularly to Figure 1, it will be seen that my-boom consists, in general, of a stationary cylinder or barrel, generally designated A. Slidably mounted in the barrel A is a rod member B, and in the outer end 10 of this rod I mount another rod C, which is adapted to be telescoped within the rod B. The microphone D is attached to the end of the rod C by the conventional hanger E. At the rear end of the tubular member A and, as illustrated, 15 directly beneath this member, I mount another cylinder or tubular member F. The members A and F contain the liquid and the pistons to be later described. The members A and F are connected at the rear end by a suitable casting G, 20 which will be described in conjunction with the operation of the boom. The other end of the member F is held by a supporting box H. Extending forward of the box H is a smaller tubular member J, fixed at the forward end by a sup- 26 porting spacer K. The box H is adapted to be supported on a stand L, which may take any form, and is arranged to swing in a vertical plane indicated by the dotted lines M and N.

In Figures 2 to 5 the construction and arrange- 30 ment of parts is shown. Referring to Figure 2, which is'an enlarged longitudinal section of the barrel arrangements with the pistons and moving parts, it will be observed that the barrel A passes through and is supported in the box H and contains an inner sleeve II, which may be of thin,

light material. The double sleeve arrangement provides a more rigid and a more durable construction. It is to bev understood that the inner sleeve H extends the full length of the barrel A 40 and is spaced therefrom at one end by a casting l2. The casting l2 also 'carriesthe barrel A and the barrel F, which are mounted therein in any suitable manner. The other end of the sleeve I I is spaced from thebarrel A in any suitable manner, not shown. For this purpose a leather ring or screws extending through the'barrel A may be used. Within the sleeve I I, the rod B -is slidably mounted and is attached to a sliding support I3 and a piston H in a manner to allow a floating action between the rod and the piston. This construction is best shown in Figure '1' and will be described later. The rod Bis shown as square for purposes of rigidity and alsoto prevent r'ota-' tion of the rod during extension. In-Figure' 1',

I have shown rollers l and I6 mounted on the barrel A. These rollers extend through the barrel and the inner sleeve II and are arranged to engage the upper and lower edges respectively of 5 the square rod B. As the rod is extended, the rollers not only prevent turning of the rod, but also act as hearing points .for the rod to prevent undue bending. On the outer end of the rod B, I mount a telescoping rod C, which is adapted to be extended by hand and on the outer end of the rod C I suspend a microphone D, mentioned before, by means of the conventional hanger E.

The foregoing description deals with the extensible part of the boom. The hydraulic means for extending As before stated, the barrel F is mounted directly beneath the barrel A, although it could be mounted above or to one side if more convenient, and is interconnected with the barrel A by means of a passage I! in the casting G. A piston I8 is slidably mounted in the barrel F and is connected on one side to a sliding weight I! and to a rack bar on the other side. The barrels A and F are filled with a liquid between the pistons i4 and I8, thus forming a liquid link between the two pistons which works through the interconnecting passage II. It is clear that the liquid connecting the two pistons being incompressible, and likewise non-expansible, will form a flexible connection between the two pistons that will operate to work the piston H in either direction. In other words, when the piston i8 applies pressure to the liquid, the piston II will normally move in response to the pressure and when the 5 piston i8 moves in the opposite direction to withdraw the liquid the piston will follow the withdrawal of the liquid, due to atmospheric pressure. It will be noted that the barrel F being constderably larger in diameter than the barrel A, the piston I! will move farther than the movement of the piston I8 and that" due to the arrangement of the two barrels the movement of the piston i4 is counter to the movement of the piston Ill. The purpose of this is to move the weight opposite to the movementof the rod B, and thereby effect a counter-balancing action. For purposes of illustration and description, I have shown an auxiliary weight I9 attachedto the piston, but it is obvious that the piston l8, being of a large diameter, may be made of sufllcient length to act as a counterbalancing weight itself, if desired. An enlarged detail of this construction is shown in Figure 6. The rack bar 20 extends through the box H and is carried in the tubular member J. The means for working the rack bar backward and forward will be disclosed later in conjunction with Figure 5. The pistons l4 and I! are connected by fluid, shown by the broken line portion in the barrels A and F. Referring the pistons l4 and It will be given. I In these views, I have shown enlarged longitudinal sections of the pistons. The piston i8 comprises a hub 2| having an intermediate flange 22. .Two cup leathers 23 and 24, placed back to back, are mounted on the hub and bearagainst opposite sides of the. flange. The cup leathers are held in place by plates 25 and 26, respectively, which in turn are held by nuts 21 and 20, respectively,

screw threadedly mounted on the ends of the .hub 2|. The hub is bored to receive a rod 29 that is pinned inthe hub by a pin 30. In order to provide a floating connection between the rod 28 and the weight I9. I pass the rod completely through the weight before attaching it to the.

the boom will now be described.

now to Figures 6 and '7, a detailed description of' weight. It will be noted that the rod does not touch the bushing Ii, which is in the center of the weight. In Figure 2 it will be seen that the bushing ll extends beyond the end of the weight and that the rod 2! is attached to this extended end by means of a pin 32, thus allowingthe piston a floating movement with respect to the weight. The weight I! is equipped with runners 33, which are circumferentially spaced and may be of any suitable material conducive to easy sliding and silent operation. Instead of making the weight separate from the piston, it may be incorporated as a part of the piston, if desirable. 0n the forward side of the piston, the hub 2| extends into a shaft 34, which is bifurcated at the end to receive the rack bar 2|. A sliding connection is used between the shaft ll and the rack bar 20, that is, there is a floating action between these two members. This is accomplished by making the bifurcation in the shaft larger than the tongue 35 on the rack. A pin 2 is used to connect the rack bar to the shaft and in order to obtain a full floating action, the pin is fixed to the tongue 35 and works in .a transverse slot 31 in the shaft 34. A piston of this nature will have free action against the wall of the cylinder and will not be forced to accommodate itself to transverse movement either of the weight or the rack bar. In connecting the piston M to the rod B, I follow the same general idea, but not the same structure. This structure is shown in Figure '7. Here it can be seen that the piston itself consists of two cup leathers 30 and 22, mounted back to back against a flange 40 on a hub H. The cup leathers are held in place by plates 42 and 43 respectively, which in turn are held on the hub by screw threaded members 44 and II, mounted on the ends of the hub 4|. The hub ll is bored as at 46, and counterbored as at I. A rod 48 extends through the bore 40 and is arranged to not touch any part of the hub II. On the outer end of the rod I mount a screw ll having a flat head. The head of the screw is adapted to flt in the counterbore 41 without touching the sides of the bore, but is arranged to engage the shoulder between the bore and the counterbore. With this arrangement, the pistonvll is loosely mounted on the rod 42. In con- Junction with the cup leather arrangement, I provide means for carrying the end of the rod B so that its weight will not come on the piston. For this purpose, I provide a hub 50 attached to the shaft 48 by a pin I. The hub $0 carries a flange 52 against which there is fastened a fibrous member 53 adapted to engage the wall of the inner sleeve II. The shaft II also extends through a block Bl, which is adapted to fit into the end of the square rod B and both the block and the shaft are attached to the rod B by a pin 55. The structure Just described will provide a full floating action of the piston II with respect to the rod B.

The actuating mechanism and the means for mounting the boom upon a support are shown in Figures 2 and 3. In'Flgure 3, I have shown a cross section of the box K. As before stated, the outer barrel A is mounted in the top of the box H and contains the inner sleeve II and the square rod B. Mounted on the barrel A are two upright standards with a bar 51 nmning between them for a handle for controlling the altitude of the boom or' for swinging. the, boom on its support. The box H also supports one end of the barrel 1", which is left open to. the box. 0n the rear side of the box I form a hub 5!. Inside the bushing, I provide a'shaft 00 which is pressed into Below the'hub I8, and a little to one side thereof, I form another hub 6|, into which a short shaft 82 is pressed and held stationary. .The

box extends around and down into a flange I.

On the front side of the box, I mount a door 64 and on the door I form another'hub I! which may be provided with a bushing. u. ii desirable. The door may be held in place by screws 81 or in any other suitable way. In the bushing 68 I mount another short shaft 00 and on the inner end of the shaft'I fix a pinion gear S9. The

pinion gear is arranged to mesh with the rack bar 20 previously mentioned. On the outer end oi the shaft 08 I attach a crank 10 for turning the gear 69.- In order to provide good structure, the inner end of the shaft 68 is turned down and extends into the shaft as shown in dotted lines 6|. From the foregoing description,

it is evident that the door 54 may be removed and the pinion gear 69 withdrawn with the door, thus giving access into the box H and into' the end of the barrel F. Due to the fact that the rack bar 20 is made as light as possible, I recommend that a roller H be positioned-beneath the bar to prevent bending. The hub GI and the shaft 62 are for this purpose. In Figure 2. it can beseen that the shaft 62 carries an arm 12 pivotally mounted thereon. ,The roller H is rotatably mounted on the end of this arm.v Means is also provided for regulating the pressure of his roller against the rack bar 20, and as shown comprises a screw 13 extending up through the bottom 01' the box H, with a set nut "for holding the screw once it is adjusted. From the foregoing it is obvious that the rotation of the crank 10 will move the piston i8 and the weight l9 backward or forward inthe barrel F. The forward end of the rack barin'its' travel is guided in a groove '35 formed in a runner 16 of any suitable material in the member J, (see Figure 5). The box H may also be formed with an oil sump '3'? having an outlet i8 therein. The whole assembly hereinbefore described is mounted on the support L. The mounting for this purpose is best shown in Figures 2 and 3. Thesupport L may be any form of boom support, such as a tripod or a standard of any description and carries onthe upper end an upwardly extending arm is which may be properly reinforced as shown. 0n the upper end of the arm, I provide a hole adapted to receive a bolt 80, which is turned down and threaded in the shaft 60. Also on the upper end of the support, there is a. slot 8| designed to receive the flange 63 of the box H,'when the box is supported by the bolt 80. It is to be understood that the, bolt 80 turns in the arm #9 and that the flange t3 slides through the slot 8|, thus permitting the boom to be swung in a vertical plane. My invention also provides means for clamping the boom in any vertical position and as shown comprises a screw threaded bolt 32 mounted in the upper end of the support and adapted to engage and press the flange 63 in the slot at. A short rod 83 may be used for turning the bolt 82.

In operation, the rod 3 is extended or retracted by turning the crank 70. As the crank is turned, the piston 58 together with the weight as is moved in the barrel F. This in turn, forces the liquid between the pistons 58 and id to move in response to. the movement of the piston i8 and the piston 55 is correspondingly moved. As mentioned before, the barrel A is of less diameter i 9,188,808 n, which is bored and equipped with bushin place and held stationary.

. sign of the rod B.

ranged so that said -tension or retraction. The whole assembly is a compact, light. durable piece of equipment that 10 requires little or no maintenance and performs silently.

Altho gh I have shown a-detailed preferred form of my invention, I am aware that certain,

parts may be modified and refined without de- 15 parting from the invention. I, therefore, intend this disclosure to coverall such alterations that come within the essence of theinvention-asexpressed in the appended claims.

' I claim: i Y m 1. In an extensible boom having a support in.- termediate its ends: a barrel; a rod slidably mounted in said barrel; a piston connected to saidrod; a second barrel having an interconnecting passage to said first mentioned barrel; a piston in said second barrel; a weight attached to said piston; liquid connecting said pistons; and means for moving said piston and weight in said second barrel to move the piston and rod in said first mentioned barrel in an opposite direction.

2. In an extensible boom having. a support intermediate its ends: a pair of interconnecting barrels; a piston in each of said barrels; a rod connected to one of said pistons and a weight connected to the other of said pistons; liquid connecting the pistons; and means for moving the piston and weight in one barrel to move the piston and rod in the other barrel in an opposite direcetion.

3. Inan extensible boom having'a support intermediate its ends: a pair of barrels having an interconnecting passage at one end thereof; a piston in each of said barrels; a rod connected to one of said pistons and a weight connected to the other of said pistons; liquid connecting the pistons; and means for moving the piston and weightin one of said barrels in one direction to move the piston and rod in the other barrel in the opposite direction.

4. An extensible boom comprising: a pair of go interconnecting barrels; means for supporting said boom intermediate its ends; a piston in each of said barrels; liquid connecting saidpistons; a rod connected to one of said pistons; a weight and a rack bar connected to the other of said 55 pistons; a pinion gear mounted in said supporting means and adapted to mesh with said rack bar; and means for-rotating said pinion gear to move said pistons, said barrels being arranged so that the movements of said pistons and their e0 associated parts are in opposite directions.

5. An extensible boom comprising: a first barrel and a second barrel having an interconnecting passage therebetween; a piston in said first barrel and a rod connected to said piston; a piston in said second barrel: liquid connecting the two pistons; a weight and a rack bar attached to the piston in said second barrel; the piston in saidsecond barrelbeing connected to the weight and rack bar to allow free transverse movement be- 0- tween the piston, the weight, and the rack bar; and means for moving said rack bar longitudinally to move said pistons, said barrels being arpistons move in opposite directions. is

a. In an extensible boom having a support intermediate its ends: a pair of interconnected barrels; a piston in each of said barrels; liquid between said pistons; a rod attached to one of said pistons; a weight associated with the other piston; means for moving the piston and weight to move the piston and rod in an opposite direction.

7. In an extensible boom having a support intermediate its ends: a pair of interconnected barrels, one of said barrels being of larger diameter and shorter length than the other; a piston in each of said barrels; liquid connecting the pistons; a rod connected to the piston in the smaller barrel; a weight associated with the piston in the larger barrel; and means for moving the piston and the weight in the larger barrel to move the piston and the rod in the smaller barrel in an opposite direction.

8. In an extensible boom having a support intermediate its ends: a pair of interconnected barrels; a piston in each of said barrels; liquid connecting the pistons; a rod connected to one of said pistons and a weight associated with the other of said pistons; and means for moving said piston with its weight in one direction to counterbalance the movement 01 the piston and rod in an opposite direction.

9. In a counter-balanced extensible boom having a pivotal support: a pair of inter-connected barrels; a piston in each of said barrels; liquid connecting said pistons; a rod connected to one of said pistons and a weight associated with the other of said pistons; and means for moving said piston with its weight in one direction to maintain the balance of said boom and to move the piston and rod in an opposite direction.

ARTHUR GEORGE wman'r.

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