US2916628A - Radiographic device - Google Patents

Description

Dec. 8, 1959 R. J. PREs-r 2,916,628

RADIOGRAPHIC DEVICE Filed March 1e, 1955 :s sheets-sheet 1 Dec. 8, 1959 R. J. PREsT RADIOGRAPHIC DEVICE Filed March 16, 1955 3 Sheets-Sheet 2 a li,

yf Mfmw i Dec. 8, 1959 R. J. PREs'r RADIOGRAPHIC DEVICE 3 Sl'xeets-Sheei'I 3 Filed March 16, 1955 far/emr Eaer Presi 2,916,628 y RADIOGRAPHIC DEvIcE Robert I. Prest, Concord, Mass., assignor to TechnicalI Operations, Inc., Arlington, Mass., a corporation of Delaware Application March 16, 1955, SerialiNo. 494,786 20 Claims. (Cl. 250-106) The present invention relates to radiographic devices, particularly to exposure shields and to control and safety devices pertaining thereto.

Some of the main objects of the invention are to provide radiographic equipment that permits the use of strongly radioactive, or other energy emitting sources in routine radiography, including remotely controlled exposures withinV buildings and radiography Where electric power is not available-to provide such equipment that can be easily adaptedfor panoramic as well Vas directional exposures, havingf'control and safety devices" for radioactive material which provides ywith a minimumv of shielding mass a maximum of safety and ease of operation.

A further object is to provide a shield with safety""de vices which permit safe pre'selection of position for panoramic exposure with a strongly emitting source, easyand safe transportation of the source from a shield to the point of exposure, and easy and safe withdrawal of the source from the point of exposure into the shield, with continuous supervision of the source position and indication thereof by conspicuous and safe signals.

A still further object of the invention is to provide a device for directional exposure with a strongly emitting source which device shields all radiation from the source excepting a beam which may be directed as required and which beam can be completely turned on or olf with a simple control for safely retrieving the source from the directional exposure position into the shield.

Additional objects are to provide directional or panoramic radiographic exposure equipment, including shielding, control, and safety components, which equipment is ruggedly constructed and especially suited for industrial application permitting the operator to expose the source from a considerable distance or from behind a shielding wall or in the case of a directional exposure device from behind the shield itself, and to provide a handling unit.

for exposure devices of the present type which is compact, rugged, easy in operation and eliminating so far as at all possible any danger of breakdown while the source might endanger the operator.

The following brief summary of the invention indicates its nature and substance, for attaining the above objects.

Equipment according to theinvention, for confining and' manipulating radioactive material, comprises a M:ce

shielding body vthat contains a guide and coninement v channel having a control port and an exit port which portsare in non-parallel axes, flexible guide conduit or channel means (such as flexible tubing or hose) extending from` at least one of these ports, ilexible elongate propelling means (such as wire rope) movable within the n guide conduit means and the channel within the shielding body, coupling means for attaching a source in a carrier or capsule or radioactive material to that end of the propelling means that is nearest to the confining channel, and which further comprises atthe other end of the propelling means actuating provisions (such as a reel) for shifting the propelling means and hence; the coupling within the flexible guide means and the con- 4fning channel. c

The channel within shielding Ibodies according to the invention is shaped as a tortuous path, preferably with end portions that are located in different, non-parallel axes. f

' For use yas a panoramic exposure device, the equipment according to the invention comprises a shielding body 4with a conning channel having a controlport and an exit port, a exible conduit (such as metal hose),4

extending from Vthe exit port, two similar exible conduits extending from the control port, flexible elongate propelling means (such as metal cable) that is movable within the channel and both guide means, and coupling means -for vattaching an energy emitting source to that end of the propelling means that is next to the exit port, for `withdrawal'of the coupling means within or for its ejection from the confining channel through the exit port; such equipment further comprises actuating means (such as a reel) at the other end of the propelling means and at the free end ofthe two conduits which extend from the control port of the confining channel, for shifting the propelling means and hence the coupling means, within exit conduit and the channel and within both control conduits, the free end of the propelling means moving in one of the conduits from the control end thus securely disposing-of this free end ina minimum ofspace, and

it also comprises, at the f ree end of the conduit whichv extends from the exit port, source positioning means for receiving the radioactive material that is attached' to the coupling means.

' For use as a directional radiographic device, equipment according to the invention comprises a shielding body that contains a confining channel with a control port at one end and with radiation directive means at the othene'nd of this channel, flexible guide means (such aS metal hose) extending from the control port, vliexible elongate propelling means (such as metal cable) that is movable `within the guide means and the channel, coupling means for attaching an energy emitting source to one end of the propelling means, for withdrawal of that end into' the channel, and at the otherend ofthe propelling means actuating means for shifting the propelling means and hence the coupling means within the channel. Safety equipment according to the invention comprises, at theabove mentioned control port of the shield contining channel, a slide Within a guide member fixedl to the shield which slide has a passage for the propelling means (such as a cable), is restrained in its movement Within'v ...t tor inserted in the cable), against lthe spring which tends to force the slide in the direction of the source when it is moved towards the exit port, whereupon the slide throws the switching means in opposite sense when the' source is withdrawn into safe position. Signalling means are connected to the switch for indicating one or the other position of the source.

The safety equipment according to the invention can further include an arrangement for indicating the deposition of the source within a receptacle in the exposing position either at the end of flexible guide means extending from the exit port, or at that port itself such as within a beam directing recess, which receptacle is slidable within a body ilxed to the flexible or conilning guide means and operates switching means when the propellingmeans pushes the source into the receptacle.

The safety equipmentincorporates, for operation by the above mentioned switching means, a signal lamp component which includes a current source (such as a battery) and ashing circuits for example including the source, energy storing means such as capacitors, gaseous discharge lamps (opening their circuit when the discharge voltage drops below their ignition voltage) and the above mentioned switching means that are operated by the source carrier (such as a capsule) or members associated therewith; these circuits are selectively opened or closed by the switching means in respective positions of the source to initiate blinking of a corresponding lamp. Instead of gas discharge lamps which serve as current interrupting as well as flash signal means, relay means can be used in the signal circuits for actuation by Fig. 2 is a front elevation, partly broken away, of thecontrol unit U shown at the top of the shield unit S1 of Fig. v1;

Fig. 3 is a cross section on lines 3 3 of Fig. 2;

Fig. 4 is a top View of the exposure or snout unit K at the end of the guide means 60 extending from the exit port e of the channel C1 of the shield unit S1 of Fig. 1;

Fig.;5 is a side view, partly in section, of the exposure unit shown in Fig. 4;

Fig. 6 is a schematic cross section through a shielding unit similar to that shown in Fig. 1, showing supporting means and indicating another position indicating arrangement;

Fig. 7 is a front elevation, partly in section, of another embodiment of the invention, in the form of equipment for directional exposure;

Fig. 8 is a side elevation, partly in section, through the front and center parts of a device according to Fig. 7;

Fig. 9 is a top elevation, partly in section, of a device according to Figs. 7 and 8; and

Fig. 10 is an axonometric view of a device according to Figs. 7 to 9, indicating the application thereto of safety and control devices similar to those shown in. Figs.' 1 to 5. y

In Fig. l, a shielding body or block is indicated `at S1, which shieldv consists essentially of a container 11 welded together from sheet iron walls and filled with lead, excepting for a source confining channel or guide C1. Turning also to Fig. 6, it will be noted that the container 11 (for example fabricated from 1A: inch hot rolled steel sheets welded full bead at all seams) is in this embodiment encased in a steel'cabinet (fabricated for example from No. 11 gage steel sheet) indicated at 12. Inorderl to ,facilitate transportation, suitable wheels '14 and legs 15 are attached to the cabinet which is also provided with4l handrails. It will be evident that various other transport provisions can be attached, for example eyes for hoisting equipment; such provisions are conventional and not herein shown. The container has further an opening 17 The channel C1 is suitably lined, such as by heavyr stainless steel tubing 16, welded or silver brazed to thei top plate of the container.

After assembly of the casing 11 lead is poured into opening 17 and after solidcation of the lead without.-

shrinks or voids the container is closed by welding a. cover 18 over opening 17, as shown in Fig. 6.

Referring to Fig. 1, it will be noted that the channel C1 has two essentially parallel end portions; these are herein referred to as control port c and as exit port e.

Mounted at the control port c is a control unit U. This control unit contains a switch actuating slide 30 playing between stops 30.1 and 30.3 of supporting means such as a guide housing 62, in a manner to be described a reel unit A. A second, similar flexible guide means 40 leads from a second opening 40.8 of the control unit U to a second opening 40.9 of reel unit A. A flexible propelling means such as a metal cable 51 is inserted within the guide conduits 40 and 50, and led around a reel 52 with crank 53 or similar means for operating the reel. Reel units of this type are commercially available and, as indicated in Fig. 1, the reel 52 has indentations or other means for establishing positive meshing with the cable. One end portion 51.1 of the cable 51 leads through the hollow interior of slide 30, and through av piece of ilexible hose 55 that is fastened to the slide 30. This end of the cable 51 is attached to a carrier such asthe capsule K containing a radioactive source. In Fig. 1, this capsule is shown in operative position within a panoramic exposure unit P which will be described below. By operating the reel 52, the capsule K can be withdrawn into the channel C1 to a position in the center of shield S1, as indicated at Ks of Fig. 1. Upon such withdrawal the other end 511.2 of the flexible cable 51 advances within hose 40 and is finally lodged in the end tube 54 of the control unit U, as indicated at 51.2s.

The control -unit U contains, as shown in Figs. 2 and 3, the above mentioned slide piece or switch actuator 30 within a housing 61 having within one wall the above mentioned supporting means 62 and having a switch cabinet that is closed by a lid 63 with screws 64. Fig. 3 also shows the channel lining tube 16 previously described with reference to Figs. 1 and 6, the flexible cable 51 carrying the capsule K at its end 51.1, the llexible hosev 50, and the sliding flexible hose piece 55 which latter is brazed to slide 30. Fig. 2 also shows the blind end 51.2 of the ilexible cable 51 and the corresponding hose end 50.2. The receiving tube 54 shown in Fig. 1 can be a hollow space within the enlarged wall of box 61, similar to the guide 62 for slide 30. The slide piece 30 has a travel limiting pin 65 and is urged, by means of the spring 66, towards the stop 30.3 constituted by the end of tubing 16. The upper end of guide hole 62 constitutes the upper stop 30.1. The slide piece 30 has a central bore 30.5 which permits free passagev of the cable 51. The hose 50 is attached to the box 61 by means of a swage coupling 68. The above described switch contacts 31, 31.2, 31.3 are incorporated in a conventional microswitch 70, which is operated by a lever 71 loaded by means of a spring 72. Three wires, indicated at 81, 82, 83 of Figs. l and 2 lead into the control box U. Wires 81 and 32 ar@ Connected to the contacts 30.1 and 30.3 as

ciegas shown in Fig. l, whereas wire 83is carried through unit U to the above mentioned panorama exposure unit P. These wires come from the signal unit F, likewise to be described below. Instead of leading the wire 83 through the control unit, it can of course be brought independently to the exposure unit P. In any case these wires are protected by appropriate conduit means, as indicated at 86 and 87 of Fig. 2.

Instead of operating the slide 30 by means of the lhose 55 shown in Fig. 1, the construction indicated in Fig. 6 can be used. In Fig. 6, hose 55 is omitted and, instead, an actuator d inserted in cable 51. This actuator is preferably a cable connector similar to that. used for attaching the source K to cable end 51.1, as lshown at k of Fig. 3. Connectors suitable for this purpose are the subject matter of my copending application Serial No. 464,551, now Patent No. 2,816,341, issued December 17, 1957. In this instance, the cable section 51.5 has the function of the hose 55 shown in Fig. l, pushing slide 30 against the force of spring 66 (Fig. 3) upon emergence from tube 16. n

The panoramic exposure unit P, sometimes also referred to as snout, is shown in Figs. 4 and 5. The flexible hose 51.1 is rigidly coupled to the open end of the snout housing block 90, by means of a screw coupling one half of which is indicated :at 91. The housing'block 90 has an axial bore 90.1 and a switch box 90.2. Within 90.1 slides a receptacle 92 with a switch operating knob 93 and a funnel portion 92.1. The sliding receptacle 92 has at its outer end a closed end piece 92.2 with a cavity such 4vas bore 92.3 just large enough to accommodate the capsule K, as shown in Fig. l where the capsule is in the position just prior to reaching the end of tube 92.2. The receptacle 92 is urged towards the cable end of the snout block by means of a spring 94, and its sliding movement is limited by the ends of a slot 95 in the wall 96 which separates bore 90.1 from switch box 90.2. A switch contact 100 is mounted on the insulating plate 101 -fastened to the lid 102 which in turn is fastened to the block by suitable means such as screws 103. The insulating plate 103 also holds in .place the above men- -tioned conduit containing the wire 83, connected to switch 100. It will be evident that upward movement of the receptacle or slide 92 will bring knob 93 into contact with switch 100, thus grounding wire 83.

At the exit port e of the shield S is a coupling unit V, shown in Fig. 6 which serves for the rigid connection of the hose 60 to the cover of the shieldunit S1. For purposes of transportation, the block 105 is unscrewed vanda similar but closed block is screwed on instead, which has attached thereto a piece of wire cable just long enough to hold the capsule K in shielded position such as indicated in Fig. 6. The capsule is then immobilized Vbetween this short cable and the connector d resting against slide 30; if the modication according to Fig l is used, the capsule is on that side held by hose 55. The exposure or snout unit, instead'of being arranged Aatthe end of a flexible conduit -as shown in Figs. l and 5, can be mounted within a directional exposure shield, for example in the manner to be described with reference to Figs. 7 to l0. v

Referring to Fig. l, the signal unit F will now be described. This signal unit is housed in a box that carries .in a conspicuous location three signal lamps which are .indicated at I, II, III. These lamps can be provided with cover glasses of different colors and appropriately labeled, such as On for lamp I, Safe for lamp II, yand Open for lamp III. The reel unit A is preferably v`mounted on the signal unit and in that case the electrical connections 81, 82, 83 can be of the same approximate length as the exible hose connections 40, 50 and 60.

The signal unit F contains, for energizing the gaseous `discharge lamps I, II, III, the following power supply ,jandrash signal arrangement. A battery 111 consists of fwo'branches 111.1 and ritz each of about 6,8 vous and has a midpoint terminal 111.5. A resistor 112 (in a practical embodiment about 2.2 megohms) is connected between the negative pole of the battery 111 and one electrode of the lamp I. The other electrode of gas discharge lamp I is connected to Wire 81 which, as described abo-ve, leads to the switch of the snout assembly P. A further resistor 113 (about 0.56 megohm) is connected in series to resistor 112 to the common terminal 115 of one electrode each of lamps II, III respectively. Resistors R81, R82, R83 (each of about 3.3 megohms) are connected between midpoint 111.5 and lamp wires 81, 82, 83, respectively. A capacitor 116 (about l lafd. in the same embodiment) is connected between ground and the above mentioned electrode of lamp I, and a capacitor 117 (about 1 nmf.) is connected between .the common terminal 115 of lamps II and III and ground. The individual cathode terminals of lamps II and III are connected, through wires 82 and 83, to contacts 31.2 and 31.3 respectively, of the control unit U. This arrangement constitutes a relaxation circuit which flashes the respective lamps upon closure of the switches in the circuits of the respective lamps. In well known manner, the battery 111 charges capacitors 116, 117 until the firing voltage of the gas discharge lamps I, II, III ,is reached, provided of course that a respective contact 100 or 31.2 or 30.3 is closed. Upon disch-arge of a capacitor through a respective lamp, the lamp supply voltage decreases and the receptive lamp goes out. The capacitors charge up again and the cycle is repeated, with the lamps flashing accordingly. In the present practical embodiment, lamps II and III are prevented from ashing while lamp I ilashes that is when switch 100 in wire 81 is closed, by means of the resistor 113 which reduces ythe voltage on lamps II and III below their tiring value when the capacitors discharge through lamp I. The resistors R81, R82, R83 have the purpose of preventing spurious signals due to leakage around the switches.

'I'he operation of the above described embodiment of the invention is as follows.

When not in use, the capsule K is in the position indicated at Ks of Fig. l, in channel C1 within the shield S1. The reel 52 of unit A is in such a position that the capsule end 51.1 of the exible cable is between the midpoint of shield S1 (indicated by Ks) and the control unit U, and the free end 51.2. is within the tube 54, as indicated in Fig. 1 at 51.2s. In this position, the capsule pushes the control tubing 55 and the slide 30 upwardly against the tension of spring 66, such that contacts 31 and 31.2 close the circuit of lamp II, indicating that the apparatus is Safe With the capsule in this safe position, the signal unit F and the reel unit A can be kept at any desired location, and the same is true of the exposure unit P. The lengths of the iiexible conduits 40, 50, 60, and of the cable 5.1 therewithin, as well as of the signal wires 81, 82, 83 will depend upon the nature of the radioactive source; by way of example, if K contains 4,000 millicurie of cobalt 60equivalent radiographically to 6,000 milligrams of radium, each of the tubes 40 and 50 will be about 25 feet long, and the tube 60 will measure approximately 2l feet.

For exposure, the shield unit S1 is wheeled or otherwise moved to within a convenient distance from the spot where the source is to be used. The exposure unit P is positioned in the exact spot where the source will be used for exposure. If the exposure point is rather inaccessible, the full length of the snout cable 60 will be utilized, but if the point of exposure is easily accessible,

Ythe shield unit S1 can be brought closer and hose 60 with wire 81 will be coiled or otherwise disposed. The operator then extends the control cables 40, 50 and wires, 82, 83 to their'full lengths straight from the shield unit, and thereupon cranks the reel in the direction indicated by arrowa, thus moving the source capsule from posi` tion Ks through the lefthand portion of channel C1, and through hose 60 into exposure P. As soon as the capsule leaves position Ks, the pressure of spring 60 against slide 30 moves the latter downwardly. Contacts 31 and 31.2 separate, and instead contacts 31 and 31.3 close `the circuit of lamp III. Lamp II, Safe, ceases to ash, and instead lamp III, Openfj begins to flash indicating that the radioactive source is in transit and probably not shielded. Upon reaching the exposure unit P, capsule K enters the funnel shaped end 92.1 of slide 92 (Figs. 4 and 5) and, upon encountering the closed end 92.3 of cavity portion 92.2 of the snout slide 92, pushes the latter upwardly against the pressure of spring 94. This causes knob 93 to make contact at switch spring 100 of wire 81, thus starting lamp I to ash. Lamp III is extinguished. Lamp I indicates that the capsule is in On or exposing position. When the exposure is completed, the source is returned by cranking the reel 52 in opposite direction until the capsule, again in position Ks, strikes the control hose 55, pushes slide 30 upwardly against the tension of spring 66, makes contact at 3-1 and 31.2, and changes the ashing from lamp II to lamp II Safe If the arrangement of Fig. 10 is used, the connector d together with the cable section 51.5 between capsule K and connector d assumes the function of the hose section 55 of Fig. 1. The connector d pushes the slide 30 towards contact 31.2 (Fig. 1) when the reel is operated in the sense opposite to arrow a, igniting lamp II, Safe When the reel is turned in the direction of arrow n, the connector d releases the slide 30, transferring contact to 31.3 and igniting lamp III, Open, instead of lamp II.

The above described apparatus can be adapted to serve as a directional exposure device, as indicated in Figs. 7 to 10 which will now be described.

Figs. 7 to l0 also indicate a channel C2 having a novel conguration that is especially effective and practical for shields of the type shown in these figures.

In these figures, S2 is a shield unit consisting of a sheet metal shell 211 containing channel C2 which is defined by metal tubing 216. As indicated in Fig. 10, this channel has the shape of a skewed, three-dimensional S-curve. The shell is again lled with lead or other shielding material. In the embodiment shown, the shield has two trunnion pieces 221.1 and 221.2, permitting rotatable suspension on a conventional supporting device such as a truck or elevator, indicated at 222.1 and 222.2 of Fig. 7. A radiation directing recess is indicated at 225, which is in this embodiment a funnel assembled from sheet metal and welded to the shell 211. The channel tube 216 leads into the funnel 225 as indicated at 216.2. At this port 216.2, an exposure unit similar to unit P as described with reference to Figs. 1, 4 and 5 can be mounted Within the shield and with only the end portion 92.1 (Fig. 5) emerging, which is fully pushed out when the source is in exposure position. As indicated in Figs. 7 and 10, the tube 216 is continued through the shell 211 to the outside thereof where it is enclosed within a tube housing 212.

At the control end 216.1 of conduit or channel 216, a control unit U2 can be mounted, in conjunction with a control unit F2, A2. The latter can be quite similar to that described above, with the difference that in this instance two signal lamps, Safe and On will be sufficient, as indicated by lamps I and II of Fig. 10, which, correspondingly, shows only the two wires 81 and 82. Since there is practically no Open position, the contact 31.3 can be omitted, together with wire 83 and lamp III. Instead of using guide conduits 40 and 50, the unit F2 can be mounted directly on the box U2, if the operator can be trusted to stay out of the direction of radiation from 225.

For operating a device according to Figs. 7 to 10, the directional exposure shield is positioned, and the specimens are arranged in its field of emission. As described above, lamp II indicates safe position. The source is then moved into position at 216.2 by turning the crank 8 of unit A2. The source is thus moved from position KS2 to K2, as indicated in Fig. 10. With the source capsule in that position, lamp I will begin to flash, indicating the On condition. When the exposure is completed, the source is withdrawn into the shield by returning the handle to its original position. Lamp I will thereupon extinguish and lamp II will again begin to flash, indicating Safe position of the source.

Since a directional exposure shield of the above described type provides complete protection if the operator remains outside of the field of radiation, the unit F2 can often be omitted, and the position of the specimen derived from and indicated by the position of crank 252. The reel can. be so arranged that a rotation of the crank completes the movement of the capsule from Safe to On position. The corresponding crank positions, 180 apart, provide a safe and conspicuous indication of the capsule position.

It should be understood that the present disclosure is for the purpose of illustration only and that this invention includes all modifications and equivalents which fall within the scope of the appended claims.

What I claim is:

l. Equipment for shielding and manipulating a carrier for energy emitting material, comprising: a shielding body containing a channel having an elongate region for confining the carrier in the approximate center of said body, said channel `extending on one side of said conlining region in a curve ending on the outside of said body in a direction that is inclined to the axis of the confining region, and said channel extending on the other side of said conning region in a curve within a plane that is inclined to the plane of said first mentioned curve and ending on the outside of said body in a direction that is askew to said first mentioned direction; flexible elongate propelling means movable within said channel; coupling means for attaching a carrier to one end of said propelling means for withdrawal with that end to said confining region; and at the other end of said propelling means actuating means for shifting the propelling means and hence the coupling means; whereby the directions of movement at the respective ends of the channels on either side of'ftheJconning region are effectively separated.

2. Equipment according to claim l wherein said shielding body is essentially cylindrical with the said confining region essentially in the cylinder axis.

3. Equipment according to claim 2 wherein the axis of said confining region is essentially diametrical of said cylinder axis.

4. Equipment according to claim 2 wherein said first mentioned curve ends essentially in said cylinder axis.

5. Equipment according to claim 4 wherein said shielding body is combined at the end of said first mentioned curve, with means for receiving said carrier and for directionally limiting emission therefrom.

6. Equipment for shielding and manipulating a carrier for energy emitting material, comprising: a shielding body containing a channel for confining the carrier, having a control port and an exit port; flexible control guide means extending from said control port; Iflexible receiving guide means extending essentially along said control guide means; flexible elongate propelling means movable within said guide means and said channel; coupling means for attaching a carrier to the propelling means at the end adjacent to said exit port, for withdrawal of the coupling means within, or ejection from said channel through the exit port; and at the free ends of said control and receiving guide means, actuating means for shifting the propelling means and hence the coupling means within the channel and for shifting the other end of the propelling means within said receiving guide means.

7. Equipment according to claim 6, wherein said propelling means is a exible cable and said actuating means is a reel engaging said'cable.

antenas 'elongate propelling means movable within said guide means and said channel; coupling means for attaching a carrier to the propelling means at the end adjacent to said directing means for Withdrawal with that end into -said channel; and rotary propelling means connected to said guide means and separate from but positively engaging said elongate propelling means for shifting the propelling means and hence the coupling means relatively to the guide means.

9. For apparatus of the type described, a shield unit for manipulating an energy emitting source, comprising a block of shielding material within said block a curved channel for confining the source having an exit port and a control port, the axes of said channel at said ports be- 1;

ing essentially askew; source propelling means atsaid -control port; emission directing means at said exit port;

and source receiving means at said emission directing means; whereby the direction of movement of the propelling means at the control port can be effectively sepz arated from the direction of emission at the exit port.

10. For apparatus of the type described, a unit for supervising an energy emitting source in its movement at the end of elongate propelling means from and into the channel of a shielding means, comprising: supporting means fastened relatively to said shielding means and having two opposite openings coaxial with said channel, for receiving said propelling means; an actuator slidingly mounted on said supporting means for movement between said openings; on said supporting means stops for tu.

limiting the movement of said actuator; biasing means for urging said actuator from one opening towards the second opening; switch means arranged for different settings depending upon the position of said actuator at points near one or the other of said openings, respectively; and actuator displacing means for defining a given distance between said source and said supporting means; whereby said switch means has one bias determined setting while the source is further than said given distance but arrival of said sourceat said distance causes said displacing means to move said actuator against said bias, to change the setting of saidswitch means.

11. For apparatus of the type described, a unit for supervising an energy emitting source in its movement at 'the end of elongate propelling means from and into the channel of a shielding means, comprising: supporting means fastened relatively to said shielding means and having two opposite openings coaxial with said channel, for receiving said propelling means, one of said openings facing said shielding means; flexible guide means fastened to said supporting means at the other opening; an actuator slidingly mounted on said supporting means for movement between said openings; on said supporting means stops for limiting said movement of said actuator; biasing means for urging said actuator from one opening towards the second opening; switch means arranged for different settings depending upon the position of said actuator at points near one or the other of said openings, respectively; and actuator displacing means for defining a given distance between said source and said supporting means, including a length of flexible guide means corresponding to said distance, leading through said first opening and fastened to said actuator; whereby said switch means has one bias determined setting while the source is further than said distance but arrival of said source at said distance causes said length of guide means to move said actuator against said bias, to change the setting of said switch means.

12. For apparatus of the type described, a unit for supervising an energy emitting source in its movement `10 at the end of elongate propelling means from and into the channel ofl a shielding means, comprising: support means fastened relatively to said shielding means and vhaving two opposite openings coaxial with said channel,

for receiving said propelling means, one of said openings facing said shielding means; flexible guide means fastened to said supporting means at the other opening; an actuator slidingly mounted on said supporting means for movement between said openings; on said supporting 4means stops for limiting said movement of said actuator; biasing means for urging `said actuator from one opening towards the second opening, switch means arranged for different settings depending upon the position of said actuator at points near one or the other of said openings, respectively; and actuator displacing means for defining a given distance between Said source and said supporting means, including a length of said elongate propelling means having an actuator displacing portion at said distance from said source within said channel, and adapted to contact said actuator; whereby said switch means has one bias determined setting while the source is further than said distance but arrival of said source at said distance causes said displacing portion to move said actuator against said bias, to change the settingk of said switch means.

13. For apparatus of the type described, a unit for positioning the carrier for an energy emitting source for exposure, comprising: supporting means fastened relatively to guide means forming a channel for propelling means, and'having at said guide means an opening for said propelling means; a receptacle-slidingly mounted on said supporting means, including on the side towards said opening, port means for a carrier at the end of the propelling means, and on the other side a cavity for receiving said carrier; biasing means for urging said receptacle towards said opening; and switch means mounted on said supporting means, responsive to sliding .movement of said receptacle; whereby entry of a carrier from said guide means through said opening and said port into said cavity moves said receptacle against said biasing means and operates said switching means.

14. For apparatus of the type described, a unit for positioning the carrier for an energy emitting source for exposure, comprising: housing means fastened relatively to a exible conduit forming a channel for a flexible cable, and having an opening at said conduit for said cable; a receptacle slidingly mounted within said housing means essentially coaxially to said conduit and said cable, including on the side towards said openingia funnel shaped portion for receiving a carrier at the end of said cable and on the other side a closed cavity for receiving said carrier; spring means for urging said receptacle towards said opening; and a switch spring mounted on said housing means for contacting said receptacle upon sliding movement thereof; whereby entry of a carrier from said conduit through said opening and said funnel portion into said cavity moves said receptacle against said spring to contact said switch spring.

15. Safety equipment for energy emitting material in a carrier on propelling means for confinement in a channel of a shielding body having two ports and an exposure port, comprising: 'a slide at said control port within a guiding'member fixed to the shielding body, having a passage for said propelling means, being restrained in its movement within said guiding member, and having control switching means for operation in an extreme position of the slide; biasing means for moving swtching *means for Operation by Said receptacle when said propelling means forces said carrier'thereinto; signal control means including a flashing circuit with a current cource, capacitor means, two gaseous discharge lamps and said control and exposure switching means; and means for selectively energizing one lamp upon operation of said control switching means and for energizing a second lamp upon operation of said exposure switching means.

16. Safety equipment for energy emitting material in a carrier on propelling means for connement in a channel of a shielding body having a control port and an exit port, comprising: `a slide at said control port within a guiding member iixed to the shielding body, having a passage for said propelling means and being restrained in its movement within said guiding member; control switching means having a confinement contact for operation in one extreme position and a withdrawal contact for operation in the other extreme position of the slide; biasing means for moving said slide in the direction towards the shielding body; means for moving said slide against said biasing means when said carrier is within the shielding body at a predetermined distance from said guiding member for operating said confinement contact, said biasing means forcing said slide in the opposite direction when said carrier is moved towards said exit port for operating said withdrawal contact; exposure means for said carrier, associated with said exit port, having a receptacle slidingly mounted thereon and exposure switching means for operation by said receptacle when said propelling means forces said carrier thereinto; signal control means including a ashing circuit with a current source, capacitor means, three gaseous discharge lamps and said control and exposure switching means; and means for selectively energizing one lamp upon operation of said confinement contact, for energizing a second lamp upen operation of said withdrawal contact, and for energizing the third lamp upon operation of said exposure switching means` 17. In equipment for manipulating a carrier for energy emitting material which can be confined within a shielding body and positioned for exposure, safety-apparatus which comprises: exposure switch means including a receptacle for said carrier and means for operating a contact upon entry of said carrier into the receptacle; coniinement switch means including an actuator whose position indicates the position of the carrier relatively to the shield and means for operating a contact when ysaid actuator indicates safe coninement of the carrier within the shielding body; and signaling means including an electric energy source, two indicating means, and connections between said source, said contact of said exposure switch means, said contact of said connement switch means, tand said indicating means, for selectively energizing -a respective indicating means upon operation of a corresponding contact; whereby one of said indicating means-responds to exposure of said carrier in said receptacle and the otherindicating means responds to safe coniinement of the carrier.

18. Apparatus according to claim 17 wherein said signaling means includes relaxation circuit means for ashing said indicating means upon operation of a contact in its respective circuit.

19. Apparatus according to claim 18 wherein said-indicating means are gaseous discharge lamps which form part of said relaxation circuit.

20. In equipment for manipulating a carrier for energy emitting material which can be conti-ned within a shielding body and positioned for evposure, safety apparatus which comprises; exposure switch means including a receptacle for said carrier and means for operating a contact upon entry of said carrier into the receptacle; confinement switch means including an actuator whose position indicates the position of the carrier relatively tc the shield and means for operating a contact when said actuator indicates safe confinement of the carrier within the shielding body; withdrawal switch means including means for operating a contact when said actuator indicates withdrawal of the carrier from the shield; and signaling means including an electric energy source, three indicating means, and connections between said source, said contact of said exposure switch means, said contact of said confinement switch means and said contact of said withdrawal switch means, and said indicating means, for selectively energizing a respective indicating means upon operation of a corresponding contact; whereby one of said indicating means responds to exposure of said carrier in said receptacle, the second signaling means responds to safe confinement of the carrier, and the third indicating means responds to withdrawal of the carrier.

References Cited in the tile of this patent UNITED STATES PATENTS 2,412,174 Rhoades Dec. 3, 1946 2,551,491 Gilks May 1, 1951 2,594,970 Monk Apr. 29, 1952 2,622,209 Hjulian et al Dec. 16, 1952 FOREIGN PATENTS 1,079,640 France May 19, 1954 v UNITED STA'lElPATENT OFFICE CERTIFICATE OF CORRECTION Patent No., 916,628 December 8,l 1959 Robert J, Prest It is hereby certified that error appears in the-printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below. l

Signed and sealed this 26th day of July 1960a (SEAL) Attest:

KARL HE.l AXLINE Y ROBERT C. WATSON Attesting Officer Commissioner of Patents

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