US2347369A - Apparatus for suspending and releasing objects - Google Patents

Description

April 25,1944. H, ROTERS 2,347,369

APPARATUS FOR SUSPENDING AND RELEASING OBJECTS Filed June 10, 1940 3 Sheets-Shet l {llllllll H6 67 7IINVENTOR \75 Herbert C. Raters I BY H. C. ROTERS April. 25', 1944.

APPARATUS FOR SUSPENDING AND 'RELEASING OBJECTS 5 sheets-sheet 2 Filed June 10, 1940 INVENTOR Herbert 6'. R0 el's BY ATTORNE Aprll 25, 1944.- H.-C. ROTERS 2,347,369

APPARATUS FOR SUSPENDING-AND RELEASING OBJECTS Filed June 10, 1940 -5 Sheets-Sheet s 125 Us jfi la.

INVENTOR tenteel Apr. 2, 3%

APPARATUS FOR SUSPENDKNG i Herbert S. Roters, Mountain Lakes, N. .L, assignor to Fairchild Camera and w:

5 Claims.

This invention relates to apparatus for, sus pending an object in the airand efiecting substantially instantaneous release thereof when desired, and more particularly to a device for holding and releasin aerial bombs.

One of the objects of this invention is to provide apparatus for-suspending an object and effecting the release thereof which is simple in structure and operation, and which is capable of releasing the suspended object at any desired instant. Another object is to provide apparatus of the above nature which is light in weight, and

which may be installed in a relatively limited.

space, and yet be capable of suspending objects of considerable weight and size. Another object is to provide apparatus of the above nature which may be attached to an aeroplane for instantaneously releasing bombs suspended thereby. Another object is to provide apparatus for holding or suspending a substantial weight in the air for indefinite periods of time, and without danger of prematurely releasing such object. Other objects will be in part apparent and in part pointed out hereinafter.

The invention accordingly consists in the features of construction, combinations of elements, and arrangements of parts as will be exemplified in the structure to be hereinafter described and the scope of thevapplication of which will be indicated in the following claims.

In the drawings, wherein there are shown several embodiments of my invention,

Figure 1 is a side elevation of my bomb supporting and releasing apparatus;

Figure 2 is a side elevation of a modified form of my apparatus; I

Figure 3 is a sectional elevation of a magnet which forms a part of my apparatus;

Figure 4 is a horizontal section taken along the line d-t of Figure 3;

Figure 5 is a Wiring diagram of a control circuit for my apparatus;

Figure 6 is a wiring diagram of a modification of the control circuit for my apparatus;

Figure 7 is a wiring diagram of another modification of a control circuit for my apparatus;

Figure 8 is a sectional elevation of a different type of magnet;

Figure'Q is a side view of the magnet shown in Figure 8;

Figure 10 is a side view of another form of my' apparatus;

Figure 11 is an enlarged section taken along the line ll-H of Figure 10;

Figure 12 is an enlarged section taken along the line l2-|2 of Figure 11;

Figure 13 is a wiring diagram for controlling a number of bomb shackles to eflect train bomb- Figure 14 is anotherwiring diagram for a different type of train bombing control: and,

Figure 15 illustrates an oscillogram showing time of current decay.

Similar reference characters refer to similar parts throughout the various views of the drawmgs.

Bomb holding and releasing apparatus as heretofore available has been in most instances characterized by complicated and weighty mechanical structure having inherently serious limitations which detract from accuracy in operation. Some of these mechanical systems utilize an electromagnet, energization of which eflects releasin operation of the mechanical system. In the use of adevice of this character, there is a substantial delay between energization of the magnet and the'release of the bomb, and a substantial amount of power is required to operate the magnet. The time delay is undesirable since it is variable, depending on supply voltage, magnet coil temperature, and mechanical friction, all of which are difiicult, if not impossible to compensate for. The inability to efiect an accurate compensation for these factors results in an error over which the operator has no control. The large amount of power necessary to operate such -systems is undesirable as the power source on an aeroplane is usually the storage battery, of limited capacity. This, of course, results in large variations in supply voltage, which naturally augment the variations in time delay. Furthermore, the variations in supply voltage prevent, or make uncertain, the simultaneous release of a number of bombs.

The time delay between energization of the magnet and the release of the bomb in a system such as that just referred to, results because of the interval necessary for the current to reach a strength suflicient to actuate the magnet, and also because of the time required for the magnet plunger to move the necessary distance to efiect the mechanical release. This time delay is often as high as one-tenth of a second, which is a substantial interval when considered in view of the high rate of speed that modern bombers attain. As noted above, a large power input to the magnet is necessary, becausethe magnet must exert a large force through an appreciable distance in a motion. As can be seen, this comprises a substantial power requirement.

Other bomb holding and releasing, mechanisms are purely mechanical, and depend upon a system of cables, pulleys and levers to eflect bomb.

release. Apparatus of this character, of course, detracts from the useful load of the plane, and in operation occasions even greater inaccuracy on the part of the operator. It is accordingly another object of this invention to obviate the above difficulties in a thoroughly practical and eillcient manner.

Referring first to Figure 1, a pair of magnets generally indicated at 5 are supported in any suitable manner by a suitable portion Of the under structure II of an aeroplane (not shown). Magnets 5 are provided with armatures I2 which are directly attached to a bomb I3. Magnets 5 are preferably connected in series, but if desired may be connected in parallel with a source of current I4, a manually operable switch I5 being provided to energize and deenergize magnets 5. When switch I5 is closed, the magnets areenergized so as to attract thereto their armatures I2, and accordingly suspend the bomb until such time as switch I5 is opened to deenergize the magnets. When switch I5 is opened, bomb I8 is instantaneously released, by reason of the character of magnets 5 described below.

In Figure 3, I have shown a section through a magnet I generally similar to but diflering in certain respects from magnet 5, this magnet being of a type suitable for effecting the instantaneous release desirable in bomb holding and releasing mechanism. Magnet I0 includes an iron body I6, in which a non-magnetic rod I1 is reciprocably disposed. An annular recess I8 formed in magnet body I6 has disposed therein a coil I9 having a suitable number of turns and layers of wire to energize the magnet. The upper portion of magnet body I6 is reduced as at 20, and the outer periphery of this portion is threaded for attachment thereto of a cap-2| or the like. Rod I'I extends through magnet body I6, and has a circular plate 22 secured to the top thereof, this plate being reciprocable in a circular recess formed by annular recess 2011. A coil spring 23' is disposed within cap 2I and presses downwardly against plate 22 so 'as constantly to bias the rod downwardly, as viewed in Figure 4. The lower end of rod I1 is reduced and threaded for attachment to an armature 25.

As is better-shown in Figure 4, magnet body I is provided with a plurality of equally spaced Preferably armature 25 (Figure in the iron portions thereof when the magnetic and hence removing the ampere-tum excitation of the magnet. Eddy currents act in the same manner as the normal ampere-turn excitation, and hence would frustrate attempts to produce a quick release. Through the provision of slots 24, the path of the eddy currents is effectively broken up. and the eilect of such currents is, of course, greatly mitigated.

Referring back to Figure 3, rod II, which sup ports armature 25, is preferably non-magnetic and slides in a bronze bushing 28. Downward travel of rod I1 and armature 25 is, of course, limited by plate 22 which in its lowermost position engages a stop formed in the upper portion of magnet body I6. When magnet I0 is energized, armature 25 is, of course, attracted to the pole faces 28 of the magnet and the minimum separation between armature 25 and pole faces 28 of the magnet body is determined by the thickness of a non-magnetic washer 29 secured ad- Jacent the pole faces in annular recess I8. It is desirable that this gap beimade as small as possible so that the stored energy of the field be reduced to a minimum.

Through the provision of spring 23, armature 25 is forced away from polefaces 28 upon deenergization of the magnet with a substantially strong force, which may be on the order of one-eighth of the magnet holding force. The full eifectiveness of spring 23 is required only when armature 25 is very close to or in contact with the pole faces. In connection with the operation of spring 23, it should be noted that the bomb as carried in any one holding device may well vary in weight in a ratio of ten to one. Hence, the force at which the magnet will release will vary in the same ratio. An extremely low release force is undesirable because the actual time of release becomes less certain due to the effect of eddy currents and magnetic hysteresis in the iron. The

spring therefore does not increase the release force of a heavy bomb greatly on a percentage basis, but does increase it greatly for a light bomb. It should also be noted that the combined effect of spring 23 and the non-magnetic gap minimize residual magnetic effects due to hysteresis in the various iron parts.

Under certain circumstances a magnet of a type somewhat different from that shown in Figure 3 may be used. To this end I provide a ma net generally indicated at I00 (Figure 8) comprising a stack of laminations IOI (Figure 9) each generally E-shaped and including a base portion I02 and arms I03, I04and I05 (Figure 8). To maintain the stack of laminations IOI fiat, heavier end plates I05 and I0! (Figure 9) are provided at opposite ends of the stack, the end plates and laminations being held together by rivets I08 (Figure 8) so placed as to prevent eddy currents.

In the spaces I09 and I I0 formed between arms I03, I04, and arms I04, I05, is disposed a suitable bobbin II I on which a coil H2 is wound (see also Figure 9).

An armature, generally indicated at H3, is also laminated and is accordingly formed of a number of strips II 4 (Figure 9) riveted together by rivets II5 between heavier end plates II6. A clevis II! is attached in any suitable manner to armature II3.

Although not shown herein, a spring, such as spring 23 (Figure 3) may be used if desired, in conjunction with magnet I00 (Figure 8) for the same purpose as described above.

Referring back to Figure 1, it may accordingly be seen that bomb I3 is supported directly by the I nets such as magnetic force of magnets It without the intervention of a mechanical system to carry the weight or the bomb. Magnets are normally energized, and hence are only deenergized when it is desired to drop the bomb. By the use of magereinabove described, release of the bomb is substantially instantaneous upon breaking of the energizing circuit of the magnets.

With reference to Figure 2, wherein there is shown a modified form of my bomb holding and releasing device, a bomb 3h having a hook ill is supported by the free end 5% of a lever as having a fixed pivot til disposed in the bomb bay (not shown) of the airplane. The lever is held in such a position that itsltip 59a is spaced a short distance from a fixed stop ti, this position of the lever being maintained by an arming pin as which is vertically slidable in a suitable guide 5, or the like. When arming pin s2 is in its lowermost position, lever 59 is maintained in bomb holding position as the arming pin prevents counterclockwise movement of the lever. The upper end or lever 59 is connected to armature magnet by a link $3 so that upon energizatlon of magnet Ill armature 25 is attracted thereto, causing slight clockwise movement of lever 59 which is possible by reason or" the clearance between lever tip sea and stop 65. When the magnet has been energized, arming pin 52 may be freely withdrawn from its bomb holding position as the upper end of lever es moves slightly clockwise by reason of the space provided between lever tip 59a and support 55. Subsequent deenergization of the magnet thus eiilccts instantaneous release of bomb 30.

Referring now to Figure 10, wherein there is shown still another form of my apparatus, a magnet generally indicated at its is suitably secured to a pair of oppositely extending flanges iii and I28 (Figure 11) preferably formed integrally with a pair of side plates iii and i225 respectively, of a bomb shackle generally indicated at 523 in Figure 10. Referring back to Figure 11, magnet I It includes a housing i2d which. is preferably cylindrical in form and on the top of which is mounted a cap I25. Cap i255 carries a terminal head 925, adapted to receive electric conduits (not shown).

Within housing 92$ is disposed a cylindrical shell I21 or the like, this shell and also housing I25 resting on and being secured to a bottom plate i283 which is in turn connected to flanges H9 and Mt, the bottom plate having a hole are formed therein for purposes described below. Within the upper portion of shell B21 is mounted an iron core I30, this core being fixed to shell I21 and accordingly immovable relative thereto. Core 83% is reduced -as at I3! and its bottom surface 532 provides suitable pole faces for the magnet. An armature 533 is movably disposed within shell I2! below core lit and also includes a reduced portion lfli, the diameter of which is the same as that of reduced portion wt of core 539. Thus the two reduced portions of the core and armature provide an annular space within which a coil Edi is disposed, this coil being fixed relative to core #313. A sleeve 8% is connected in any suitable manner to an enlarged portion I38 of armature 333 so that upon energization of the magnet sleeve I and armature I33 move together.

Core I39 is provided with a recess I31, a similar recess lab being formed in the upper part of armature I 33, and in these two recesses is disposed a spring use. The purpose and function of spring 889 is siinilar to that of spring 23 (Figure 3) of magnet Ill, 1. e. upon deenergizatime of magnet H8 (Figure 11) the forces acting on armature 533 which tend to draw it downwardly from core IBb are augmented by the thrust of spring I39 so as rapidly to separate the upper surface of armature Kit from pole faces 532.

A stud or the like generally indicated at I60 is threaded into the lower end 536 of armature 533 and includes a reduced portion Ill formed between a collar I42 and a lower bifurcated and M3. An armature I ti l is rotatably mounted as by a bushing I 55 on reduced portion tilt of stud M8, and carries at its opposite ends a pair of bobbins lit and I61 on which are respectively mounted coils Hit and its (see also Figure 12). Still referring. to Figure 12, shell ill has formed thereon apart a pair of pole pieces I55 and iEI, each being provided with a stop I52 and 153, respectively. Upon energizatlon of coils M8 and I59, armature M l rotates, i. e. its ends are attracted to pole pieces 55% and I5l until these ends abut stops 552 and 153.

As may be seen in Figure 11, a hub portion of armature Mil is attached as by a spacer collar or the like 15d to an arm 555 which is accordingly rotatable with armature ld l about the reduced portion of stud Hill. As shown in Figure 12, arm I55 may be substantially equal in length to the diameter of housing 125, and accordingly extends through slots I55 and 551 formed in the sides thereof, shell I21 being similarly slotted. The upper portion of each of these slots is elongated as shown at' I58 (Figure 11) each of the slots thus being generally of the shape of an in-' verted L (see also Flgurelfl). It may now be seen that when armature MI; (Figure 12) is'rotated by reason of the energization of coils M8 and Mil, arm I55 rotates therewith in counterclockwise direction to the dotted line position into the upper portions I58 of the slots. When in this position armature I33 (Figure 11) is not locked against downward movement and depends on the magnetic force thereon to prevent release. Upon deenergization of coils i 58 and M9, however, arm I55 (Figure 12) may swing back into slots I55 and I51 under the bias of spring I59, this spring having one end connected to arm I55 and the other suitablyconnected to the bottom of pole face I50. It should be noted that movement of arm I55 by coils its and I49 is impossible unless magnet H8 is energized to lift plunger I33 and thus remove the load from arm I55.

As shown in Figure 11, clevis M3 is connected to thesupper end of a link I60, which extends downwardly through hole I29 in bottom plate I28 into the space between a pair of plates ISI and I .72 secured to side plates I22 and I2I, re spectively, of shackle I23. The lower end'of link 464i (Figure 10) is pivotally connected to a lever I83 having a fixed pivot at I55 on shackle I23. Lever I63 includes a top surface I65 which supports a plate I66 having a fixed pivot at I61 on the bomb shackle. A lever MB is pivoted to plate I35 as at I69 and has a fixed pivot at I16 on a suitable lug or the like I1I extending from an elongated arm I12 reciprocably mounted between plates ISI and it? (Figure 11) in the upper portion of shackle I23. Arm I12 is generally U-shaped in cross section and is provided with a slot I13 through which a strut ItIl extends.

To the opposite ends of arm 112 are pivoted a pair of links I 19 and 180 which respectively have fixed pivots at I8! and I82 at the ends of shackle I23. Levers I19 and E80 are respectively provided with holding ends I83 and I84 which are movable between open and closed positions with respect to slots I85 and I86 formed in the ends of shackle I23. These slots are provided to receive the supporting hooks (not shown) of the bomb, so that the bomb may be suspended from the shackle.

It will now be seen that when a bomb is supported in shackle 123, the weight of the bomb is transmitted through levers I18 and I86 in such a manner as to force arm I12 to the right. This force, in turn, presses plate I66 against lever I63 which in turn pulls link I66 downwardly. This force tends to draw link I66 (Figure 11) downwardly and does not effect such downward movement when magnet 84s deenergized and arm I55 is inregistry with slots I56 and I51.

When coils I48 and I49 (Figure 12) are deenergized, arm I55 is in the full line position wherein it supports the weight of the bomb as transmitted through link I66 (Figure 11). When, however, magnet H8 is energized, its armature I33 is attracted upwardly against core I36 and at the same time arm i55 (Figure 12) swings counterclockwise by reason of the energization of coils I 48 and I69, which is simultaneous with the energization of the magnet. It should also be noted that the arm is free to swing by reason of the transmitted weight of the bomb being removed therefrom and supported entirely by the magnet. By reason of the arms swinging and registry with slots I56 and I51, the ends of the arm are free to ride down these slots upon deenergization of the magnet. Further in this connection bobbins I46 and I41, on which the coils I48 and I48 are mounted are preferably made of copper or similar material and accordingly act as lag coils upon deenergization of coils I48. and I49, the deenergization of these latter coils being simultaneous with the deenergization of the magnet. Hence the bobbins cause the magnetic flux produced by coils I48 and I49 to decrease at a rate slower than that of the flux produced by coil 25I (Figure 11) in magnet H8. Hence, when magnet Il8 isdeenergized, link ISO is free to move immediately downward, by reason of the transmitted weight of the bomb exerted thereon, and during this downward movement arm I55 rides downwardly in slots I56 and I51. Of course, as link I68 moves downwardly the system of levers, including levers I63, I68, arm I12 and levers I19 and I88 are rapidly moved into their release position by reason of the force of gravity acting on the bomb. m This bomb releasing 'movement is also expedited by the provision of spring I38 (Figure 11) which tends to increase the rapidity with which armature I33 separates from core I38.

When it is desired to restore the apparatus to bomb holding position, link I68 is raised in any suitable manner until bar I55 reaches the level of upper portions I58 of slots I56 and I51, the various coils, of course, being deenergized. When the arm reaches this position spring I58 (Figure 12) moves the arm clockwise into slots I58, and the apparatus is thus restored to what might be termed mechanical bomb holding position.

It may now be seen that with the apparatus of Figure the bomb may be securely held without the necessity of energizing magnet II8 until just before it is desired to release the bomb. When it is desired to release the bomb, magnet II8 becomes the principal bomb holding factor by reason of its energization, the safety device provided by arm I (Figure 12) being moved out of bomb retaining position so that deenergization of the magnet and of the coils I48 and I49 results in immediate bomb release, as described above. It will be undexstood that this last-described formof my apparatus, i. e. as shown in Figures 10, 11 and 12, may be controlled by nature of the circuits shown in Figures 5, 6 and 7. It will of course be understood that magnet H8 (Figure 11) may be of the same general type as that shown in Figures 3 and 4, or may be of the laminated type shown in Figures 8 and 9, depending upon which is the more desirable under the given circumstances.

It may now be seen that in any of the several forms of my apparatus hereinabove described,

substantially instantaneous release of the bomb may be effected, when desired. As hereinbefore noted, it is desirable that a rapid collapse of the magnet field be effected in order to attain quick bomb release. To accomplish this rapid collapse, it is not only necessary to prevent eddy currents, but also the stored mag-. netic energy of the field must be quickly dissipated or removed. Mere interruption of the magnet circuit by means of the switch usually results in an are which allows the magnet current to be sustained for a relatively long time because of the low resistance of the arc. To mitigate the formation of a detrimental arc, I have provided the circuit shown in Figure 5. The inductance and resistance of magnet II) are indicated at 84 and 65, respectively, 'and the ter minals 66 and 61 of the magnet are shunted by a condenser 88. Terminal 66 is connected to condenser 68 by lines 68 and 18, magnet terminal 61 being connected thereto by lines 1| and 12. Line 68, which includes therein a switch 13 preferably of the quick break type is connected to a battery 14. Line 1|, which includes a switch 15 is also connected to battery 14. Switch 13 is normally closed while switch 15 v is normally open, the latter being closed only when it is desired to energize the magnet.

Assuming that switch 15 is closed and the magnet energized by battery 14, the current through the magnet will be in the direction shown by the arrow A (Figure 5) with the battery polarity as shown. Condenser 68 is accordingly charged to the same voltage as the battery and will have the polarity indicated. When magnet deenergization is desired, quick break switch 13 is opened. At the instant this switch is opened, condenser 68 will maintain the potential across the magnet and the magnet current will be diverted through the condenser in the direction of arrow B. This will cause the condenser to discharge as it supplies energy to maintain the magnet current. As the surge of current continues, the condenserpolarity reverses, resulting in the condenser being charged by the stored energy of the magnet. This process continues until the magnet current falls to zero, at which time the stored energy of the magnet is, of course, zero. The current will next reverse and the energy stored in condenser 68 will be eturned to the magnet. In this manner, an electrical oscillation will be produced, the period of the oscillation being determined by the relative values of the effective magnet inductance and the caascasce attenuated as, for example, by shunting magnet l and condenser 68 by a resistance 82 com nected to lines 6d and ii.

When the magnet release circuit is timed by condenser as (e the magnetic flux falls with great rapidity to zero and then builds up in the opposite direction because of the oscillation produced. This happens so fast that armature 25 (Figure 3) moved by the force of gravity alone would not have time to get out of the held of force of the magnet during the interval that the flux has fallen to the release value, passed through zero, and built up in the opposite direction to a value suficient to hold the armature. To prevent this, I have provided a clearance indicated at d3 (Figure 3) between the armature clevis 25a and a rod pin ts which attaches link or strut 63 to armature 25 (see also Figure 3). Thus, when the flux falls to the release value, rapid initial movement of the armature by spring 23 (Figure 3) is efiected, and by reason of clearance 3% armature 25 quickly moves out of the field oi force of the magnet and hence preventspickup thereby on the second rise of the flux.

It is sometimes advantageous to increase the damping of the oscillation by inserting a resistance in series with condenser t8 (see Figure 6). This increases the resistance of the circuit for the oscillating current, but does not afiect the operation of the magnet from the battery. Likewise, the condenser 68, or a part of it, may be placed in shunt with switch it. A circuit combining all of these elements is shown in Figure 6, wherein a resistance l5 is shownin series with condenser 68, and at least a portion of condenser 68 is placed in shunt with switch 53.

With reference to Figure 7, I have shown a circuit for supplying magnet current from the plate circuit of a high vacuum tube generally indicated at TL Magnet it has its coil is connected in the plate circuit of tube ll, and the plate power is supplied from a battery 18. The tube grid We is connected to a quick acting switch 79, and when coil is is to be energized, switch i9 is closed against contact 80. This results in a zero bias on grid lie and allows a large plate current to flow. When deenergization of coil is is desired,

switch 19 is moved to a contact M, which is connected to a battery 84. Engagement of the switch with contact 8| places a high negative bias on the grid which causes the plate resistance of tube 11 to increase to a relatively large value, and hence causes the current through coil is to die away with great rapidity. It will thus be seen that where the circuit of Figure 7 is used, all possibility of any arcing or sparking in the magnet circuit is precluded. Hence there is eliminated any possibility of variation in release time due to this cause.

Certain bombing missions require a type of bombing sometimes termed train bombing" wherein the bomber carries a large number of relatively small bombs which are sequentially released at the desired time. Bombing of this type accordingly requires bomb shackles equal in number to the bombs carried, and the bombs should be released in correctly timed sequence in order to efiect the correct pattern necessary for accuracy.

To this end a desired number of shackles, such as shown in Figure 10, for example, are secured to the airplane, and are controlled by the circuit shown in Figure 13. In this circuit the bomb supporting magnet coils are indicated at B B and control arm or latch 555 are indicated at L L and L one side oi coils B B and B is each respectively connected by lines ltd, is! and id! to a line its which is in turn connected to one side of a battery ltd. The other side of battery its is connected by a line N35 to a terminal wt of a switch generally indicated at 59?. Switch i9? includes two or more additional terminals E98. its and 2%, respectively connected to lines 26L its and 2%, in turn connected respectively to the other sides of coils B B and B Thus these coiismay all be connected across battery i9 5 at one time by a switch arm res, when the arm is in the position shown in Figure 13. Preferably condensers C C and i) are connected in the circuits oi coils B, B and B respectively, in shunt with switch is? similarly as shown in Figure 6.

One side of latch coils L L and L (Figure 13) are connected by lines Edd, 2% and 223? to one side or battery 3% by way of line N3, the other side of these coils being connected by lines 288, 2st] and lid to a line Ell connected to the other side of battery Add by wayot line Hi5. Lines 208, 2st and did, respectively, include switches M2, 283 and 2M for control or the individual latches. Thus, if it is desired to release the bombs supported by magnets B and B switch 206 is closed, as shown, as are. also switches 21; and 213, Thus, when switch arm 2% is opened, the bombs held by magnets B and B are released, in timed sequence but the bomb held by magnet B is not released as its safety latch L was not energized to bomb releasing position, as its controlling switch 22s was left open. Of course, if all the safety latch switches 2l2, 22s and 2% are closed, then all of the bombs are released upon opening of the magnet circuit by movement of arm 2%.

As shown in Figure 18, latch coils L L and L can be connected separately. If desired, however, they'can be wired in parallel with the main magnet coils 18 B and B The first type of connection provides somewhat greater flexibility of operation in that mechanical bomb suspension may be returned to after magnet energization. In the second type of connection both the latch and magnet coil are excited simultaneously, mak ing it impossible to return to mechanical suspension subsequent to main holding magnet ener gization, as will be described below.

As shown in Figure 14 the latch coils L L .1. and L are wired in parallel to magnet coils B B, B and B and as a switch am 220 engages one or more of contacts 22l-22d the corresponding latch and magnet coils are energized simultaneously. Switches 225-228 are preferably provided in the respective circuits so that any one or any combination thereof can be disconnected to preclude energization thereof and subsequent bomb release. The circuit in Figure 14 is used under circumstances as where it is not permissible to lift all bombs simultaneously as would be the case where the circuit of Figure 13 is used. As shown in Figure 14, -bomb magnets B and B might bein one bomb bay, while magnets B and 3' might be in a different bay. Thus at any instant two magnets in different bays would be energized. If desired only one bomb magnet may be energized at a time, the only requisite being that the time required for energization be less than the desired time between bombs.

Thus, where train bombing is desirable, the several bomb shackle magnets may be energized and rapidly deenergized sequentially to efiect 3 while the coils leg and its (Figure 12) which rapid, timed release of the bombs at suitable 'efiect the desired movement of armature IM and accordingly arm I55. Accordingly coils I48 and M9 may be dispensed with, if desired, and portion I38 of armature I33 may be thinned to the proper extent so as to produce asubstantial increase in its magnetic reluctance. The flux lines, upon energization of magnet II8 will accordingly be concentrated in the area of pole faces IEI and I52 (see Figure 12) so that armature I44 will tend to orient itself with respect to the pole faces when the transmitted load of the bomb is removed from arm I 55. Orientation or alignment of armature I, of course, moves arm I55 into alignment with slots I56 and I? through which the arm may pass upon magnet deenergization to release the bomb. It should be noted that the transmitted weight of the bomb plus the bias of spring I 39 moves mag net armature I33 so rapidly as to preclude reentrance by spring I59 of arm I55 into horizontal slots I58 before the arm has passed belowillustrative of an oscillogram which shows the release characteristics of the shackle of Figures 10, 11 and 12 for a load of about the maximum rated load of the shackle, and connected in a circuit such as is shown, for example, in Figure 6. The lower curve 230 is representative of a timing wave, the time between adjacent peaks thereof being one-thousandth of a second. The upper curve 23I is representative of the current of coil 25I (Figure 11). The horizontal line 232 represents the zero value of this current, while the horizontal line 233 shows the steady value of the magnet current whilev the coil is energized and prior to the release. At time X, the coil circuit is opened and the current decays from its steady value 233 to zero on the curve shown. At time Y the magnet plunger or armature starts moving, and at time Z the bomb hooks I83 and I84 commence to open. It will be noted that this time is slightly less than two-thousandths of a second after the initiation of the release at point X. The actual release, 1. e. the release of the magnet armature I33, occurs in an even I shorter time before the current first reaches zero. This operation results from the action of spring I39 and the weight of the bomb.

As many possible embodiments may be made of the above invention and as many changes might be made in the embodiment above set forth, it is to be understood that all-matter hereinbefore set forth, or shown in the accompanying drawings, is to be interpreted as illustrative and not in a limiting sense.

I claim:

1. In bomb release apparatus or the like for supporting and rapidly releasing a mass, including a support, holding means associated with said mass to permit it to be supported by said support against forces tending to release it therefrom, magnetic material forming part of said ing a magnetic force to attract said magnetic material to support said mass, the combination of circuit comprising magnetic means, a source of D. C. electric power for energizing said magnetic means to attract and hold a piece of ma netic material, a switch in said circuit operable to break said circuit to deenergize said magnetic means, and means in said circuit causing the decaying current existing therein after said circuit is broken to oscillate, whereby said piece of magnetic material is released more rapidly than would be the case if said oscillation did not exist.

2. In bomb release apparatus or the like for supporting and rapidly releasing a mass, including a support, holding means associated with said mass to permit -it to be supported by said support against forces tending to release it therefrom, magnetic material forming part of said holding means, and magnetic means for exerting a magnetic force to attract said magnetic material to support said mass, the combination of a circuit comprising magnetic means, a source of D. 0. electric power for energizing said magnetic means to attract and hold a piece of magnetic material, a switch in said circuit operable to break said circuit to deenergize said magnetic means, means in said circuit causing the decaying current existing therein after said circuit is broken to oscillate, and resilient means urging said piece of magnetic material away from said magnetic means, whereby said piece of magnetic material is released more rapidly than would be the case if said oscillation did not exist.

3. In bomb release apparatus or the like for supporting and rapidly releasing a mass, including a support, holding means associated with said mass to permit it to be supported by said support against forces tending to release it therefrom, magnetic material forming part of said holding means, and magnetic means for exerting a magnetic forceto attract said magnetic material to support said mass, the combination of a circuit comprising magnetic means including an iron body forming a magnetic circuit closed by an armature member, a source of D. C. electric power for energizing said magnetic means to hold said armature, said body and said armature each being provided with slotted portions to reduce eddy currents in said magnetic circuit upon deenergization of said magnetic means, a switch in said circuit operable to break said circuit to deenergize said magnetic means, and means in said circuit causing the decaying current existing therein after said circuit is broken to oscillate, whereby said piece of magnetic material is released more rapidly than would be the case if said oscillation did not exist.

4. In bomb release apparatus or the like for supporting and rapidly releasing a mass, including a support, holding means associated with said mass to permit it to be supported by said support againstforces tending to release it therefrom. magnetic material forming part of said holding means, and magnetic means for exerting a magnetic force to attract said magnetic material to'support said mass, the combination of a circuit comprising a solenoid a source of D. C. electric power for energizing said solenoid to attract and hold a piece of magnetic material, a

holding means, and magnetic means for exert- 76 switch in said circuit operable to break said circuit to deenergize said solenoid and a condenser connected in parallel with said .solenoid to form therewith a resonant circuit causing the decaying current existing therein after said circuit is broken to oscillate, the inductance of said soleasc'nsec noid and the capacity of said condenser determining the frequency of oscillation of said decaying current. whereby said piece of magnetic material is released more rapidly than would be the case if said oscillation did not exist.

5. In bomb release apparatus or the like for supporting and rapidly releasing a mass, including a support, holding means associated with said mass to permit it to be supported by said support against forces tending to release it therefrom, magnetic material forming part of said holding means, and magnetic-means for exerting a magnetic force to attract said magnetic material to supportsaid mass, the, combination of a circuit comprising a solenoid, a source of D. C. electric power for energizing said solenoid to attract and hold a piece of magnetic material,

' mining the frequency of oscillation of said decaying current, and a resistor connected in parallel with said solenoid and said condenser to damp the oscillation in the resonant circuit formed thereby to speed the decay of said transient current, whereby said piece of magnetic material is released more rapidly than would be the case if said oscillation did not exist.

HERBERT C. ROTERS.

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