US2469594A - Hoist-lower control - Google Patents

Description

y 1949- G. DANFORTH HOIST-LOWER CONTROL 2 Sheets-Sheet 1 Filed July 26, 1947 y 1949- G. L. DANFORTH 2,469,594

HOIST-LOWER CONTROL Filed July 26, 1947 2 Sheets-Sheet 2 Patented May 10, 1949 HOIST-LOWER CONTROL George L. Danforth, Danvers,. Mass assignor. to Submarine Signal Company, Boston, Mass., a

corporation of Delaware Application July 26, 1947; Serial No. 763,9 19

6 Claims This invention relates to means for: operating ahdevice which must be extended into or retracted fromafluid medium. Such devices have been commonly used in underwater sound communication. where a sound projector is extended lll'tOthB water from. a vessel. The vessel may be atsubmarine, or-a surface vessel, or the projector may-'be on: some overboard apparatus into which it-isretracted when not in use.

Such sound. projectors are usually large and heavy. They must often be'extended a number of feet' intouthe. water, and the extension and retractionmust also be-donerapidly and in such a manner't-h'at no mechanism is injured or damaged; The mechanism, when retracted within the vessel, usually is" seated in a so-called sea chest through'which a shaft extends into the vessel. A-watertight' packing 'surrounds'the shaft and when theprojector isretracted, or extended to its furthest position, a flange surrounding the shaft comes-to rest on a limit collar for the purpose ofv properly supporting the shaft and thus aiding in providing a watertight seal.

While it is desirable to extend and. retract the apparatus quickly; it is also-desirable to seat the apparatus in its extreme positions carefully and slowly. In the prior art this has usually been done by shutting off the power through the driving-motor a little before the projector reaches its final position and permitting the shaft to coast until. the final .position has been reached. Since it is diflicult to cut the power as accurately as desired,sometimesthefmotor drives the projector hard against its'seat-and provides a substantial and perhaps damaging impact betweena limiting collar and the flange. If, on the other hand, the-motor is turned off itoo early the gear may not seat sufiiciently tightly for best storage or efiicient use.

In accordance with the present invention, means are employed toreduce the speed ofthe motorwhen it is desired to seat the apparatus in=;its limiting. positions. This,- in the present invention; may be-. accomplished in a particular manner without-the use ofcontrol rheostats by. operatingthe motor: through: a gaseous conductiontubein which: the firing-portion of the electrical". power cycle may be controlled. or selected.

The; speed of the motor may be reduced-near thelimits of travel of the projector and shaft by.

causing current to flow through the gaseous conduction tubeduring a comparatively shorter portion of therelectrical power cycleso thatnot only will the motor creepalongat slow speeds but the. average power will be lessyalthough the. ability toseatthe sound projection gear in a limit position will be just'as-efiective.

Further advantages and features of the invention will be apparent from the description of an-embodiment thereof that follows, reference beinghad to theaccompanying drawing, wherein Fig. 1. illustrates in electrical and mechanical scheme a system inaccordance with the invention; and

Fig 2 is. an enlarged view of the sea chest and soundprojector of Fig.1, the sea chest being shown insection,

Inthe drawing, an underwater sound-projectorreceiver. P is shown being lowered froma sea chest'C into the water (not shown) beneath the hull of the-vessel in-which' the apparatus 1'sv installed; 'the projector P is mounted on a shaft S:-which projectsthroughthe top of the sea chest G-by waymf awatertight seal (Fig. 2) comprising packing material W disposed between the shaft and .two: pressure collars K, K which surround the-shaft and. are pressed together by bolts B. Oneof thecollarsK has a flange K by which the collar is fastened to the top of the sea chest C, as bybolts-X. A asket Y is placed between the flange K and the top of the sea chest to provide-a watertight joint. Pressure on the collarsK; Keffects a watertight seal between the sea chest 0 andthe shaft S. The shaft S must be.--abie readilyto move through the packing material W to hoist and lower the projector P, andtothat end is ordinarily lubricated with azproper grease (not shown). It will be appreciated that while the packing material W should bei com'pressed" sufficiently to keep water out ofthe "vessel; the compression should not be so great as: to prevent theshaft S-fromsliding or turningtherein,

Two. inwardly bevelled. limit collars V, V are provided inside the sea-chest-C, one at the top andv-one .at the bottom, surrounding the shaft S. A disc-like. flange J, bevelled: at. both peripheral edges, fitssimply inside the sea chest C between the: two 'collars'V, V, and is rotatably mounted orrtheshaft S, being retained against longitudinal displacement by alpair of stops'L, L. The flange J is firmly seatedin-oneor the other of the limit collarsV, V. whenthe projector P is in the fully hoistedor-fully lowered posititon.

A. clirect current. type, reversible motor M, (Fig.1) having an. armature A and fieldcoil F, which may .in.a usual: manner be separately excited, drives.-.the.shaft. S. to hoist or lower the. projector vP by wayofna. rackand pinion gear arrangement having. a gear wheel Q in mesh with rack teeth T on the shaft S. If it is desired, reduction gears G may be interposed between the motor M and gear wheel Q. Two projecting dogs D-i and D-2 are mounted on the shaft S in spaced apart relation for the purpose of operating hoist and lower limit control switches E--i and E2 respectively, as will be explained below.

Power is furnished to the motor M through a pair of power input terminals l I and I2, to which is connected the primary winding I3 of a power transformer H4. The secondary winding I5 of this transformer is connected to the armature A of the motor M in series with a multi-pole doublethrow switch I6 and a gaseous electron discharge rectifier tube H. The switch I6 has three switch blades 2|, 22, and 23, which are ganged together and operated simultaneously by a relay coil 24. When the coil 2G is deenergized, the switch blades are closed on their lower contacts 25, 2B, and 2'! respectively, as shown in the drawing, and when the coil 24 is energized, the blades move together into contact with their upper contacts 28, 29, and 30 respectively. The first two switch blades 2| and 22 are connected to the armature A of the motor M, and the third switch blade 23 is connected to the control grid SI of the rectifier tube ll, The upper contact 28 of the first switch blade 2| and the lower contact 26 of the second switch blade 22 are joined together and connected to one end of the secondary winding iii of the power transformer I 4. The other end of this secondary winding is connected to the anode 32 of the discharge tube [1. The lower contact of the first switch blade 21 and the upper contact 29 of the second switch blade 22 are joined together and connected to the cathode 33 of the rectifier tube ll. The first two switch blades 2! and 22 of the switch It are thus operated as a double-pole double-throw reversing switch for the motor M, while the rectifier tube I1 is operated as a current regulator or speed control for the motor, as will be explained below. The relay coil 24 of the switch it is energized through a pair of input terminals 35 and 36, to which the coil is connected in series with a single-pole single-throw, or on-ofi type hoist-lower switch 31, shown in the off position. When this switch 31 is in the off position, the motor M is operated to lower the projector P, and when this switch is closed, the motor M hoists the projector P into the sea chest C.

The amount of power passed by the rectifier tube H is controlled by the amount of negative bias furnished to the control grid 3|, which bias is furnished from a source of unidirectional bias potential (not shown) by way of two bias potential input terminals 4| and 42, of which the positive-potential terminal 42 is connected to the cathode 33. The bias potential terminals 4! and 42 are connected to two bias control networks, N-l and N--2, comprising in part the hoist controls and the lower controls respectively, as shown in dotted line boxes in the drawing. The operation of each network N-l and N-2 is controlled by the hoist or lower limit control switches E-l or E2 respectively. As will be recalled, the hoist control switches E-l are operated by the upper dog D--l on the projector shaft S, and the lower control switches E2 are operated by the lower dog D-2 on the shaft. The grid 31 is connected to one or the other of the networks N-l or N-2 by way of the third switch blade 23 of the multi-polar switch It. The upper contact of this switch blade is connecetd to the first or hoist control network N-l while the lower contact 2'! is connected to the lower contro network N-2. Thus when the motor M is being operated to lower the projector P, as shown, the bias potential furnished to the rectifier tube 1'! is controlled by the lower control network N-2 and its limit control switches E-2. On the other hand, when the hoist-lower control switch 37 is placed on the hoist position, to energize the relay coil 24 of the multi-polar switch IS, the motor M is reserved to hoist the projector P, and the bias potential of the rectifier tube H is controlled by the hoist control network N--l and the associated limit control switches E--I. A current-limiting resistor 43 is connected in series in the grid circuit, and serves to limit or prevent the flow of grid current as desired. A grid-potential smoothin capacitor 44 is connected from the grid 3| to the cathode 33.

Considering now specifically the hoist control network N-I and the therewith associated hoist control switches E-l, the network has a potential divider resistor 50 connected across the bias potential input terminals 4! and 42. This resistor has three taps -5l, 52, and 53, at which are available three different potentials for the grid 3!. The first tap 5! furnishes a potential that is at most only slightly negative with respect to the cathode 33 potential, so that the rectifier tube ll operates over a sufiicient portion of the conductive half-cycle to operate the motor M at full speed, The second tap 52 furnishes a more negative grid bias potential for reduced motor speed, and the third tap furnishes a still more negative grid bias potential substantially to cut off the tube ll and stop the motor M. Control of an electric motor like the motor M with an electron tube by varying the grid bias of the tube is described more fully in Patent No. 2,163,632 to H. A. Satterlee.

The bias potential that is to be furnished to the grid 3| is selected by a pair of single-pole double- throw switches 54 and 55. The first switch 54 has its first free terminal 56 connected to the first tap 5|, and its second free terminal 51 connected to the second tap 52. The second switch 55 has its first free terminal 6!] connected to the blade terminal 58 of the first switch 54, and its second free terminal 6| connected to the third tap 53. The blade terminal 52 of the second switch 55 is connected to the upper free terminal 39 of the third switch blade 23 of the multi-polar switch l6, and through that switch blade 23 to the grid 3! when the hoist-lower switch 3'! is in the hoist position.

The two bias control switches 54 and 55 are controlled by a pair of relay magnets coils 64 and 65 respectively, each switch being closed on its first free terminal, as shown in the drawing, when the therewith associated coil is energized, and on its second free terminal under the control of a suitable biasing spring or the like when the therewith associated coil is not energized. Energizing current for the relay coils 64 and 65 is furnished by way of a pair of relay power terminals 66 and 61. The first relay coil 64 is connected in series with a first normally closed switch 14 of the hoist control limit switches El, and through this switch across the relay power terminals 66 and 61. The second relay coil 65 is connected in series with a second normally closed switch T5 of the same hoist con trol switches El, and through this switch across the relay power terminals 66 and 61. These two normally closed switches 14 and 15 are properly positioned with relation to the upper deg D-l on" the projector'shait S to effect hoist limit control, as will be described below. The relay coils B4 and 65'are both energized when the hoist control "switches El are both closed. If desired,'the relaypower terminals 66 and 61 and tiiej'hoi'st-Iower relay power terminals 35 and 36 may be connected to the same power source.

The lower control network N--2 and its limit control switches E'2'pefr'form the same function in a'lowering operation as do the hoist control network Ni and limit switches E|, and are substantially identical thereto in structure. Aoco r' clingly, the various parts in the lower control network and control'switches bear the'same reference characters as the corresponding parts injthe hoist control network and switches. The bias potential output terminal 62 of'the lower control network N2 is connected to the lower free terminal 27 of the third or grid circuit switch blade 23 of the multi-polar switch Hi. The potential divider resistor 5% of the lower control network N-2 is connected to the bias potential input terminals 4! and G2 in parallel with the corresponding resistor 50- of the hoist control network N- -l. The relay coils 6 3 and S5 of the lower control network are energized in the same fashion and from the same power source as the corresponding coils 64 and 65 of the hoist control network N-l.

As shown in the drawing, the system is lowering the projector P. The lower control network -N- 2 is connected to the control grid 3i, and the two relay coils 64 and 65 thereof are both energized. The least-negative-bias-potential tap 5| is thereby connected to the grid 3 i, and the motor M i s operating at full speed. The lower control switches E2 are so disposed that at a predetermined point along the path of the shaft S the lower dog D-Z pushes open the first switch M and opens the circuitof the first relay magnet coil 64 of the lower control network N-2. The first'swit'ch 54 then changes position, and connects the second bias potential tap 52 to the control grid 3|. A more negative bias potential is now applied to the control grid, and the rectifier tube ll conducts at a later time in each conductive half cycle of the energizing power than formerly, so that the average power furnished to the motor M is decreased, reducing the motor speed. Lowering of the projector P proceeds now at a reduced speed until the flange J is firmly seated in the lower limit collar V at which time the lower dog D-2 opens the second switch 15 of the lower limit control switches E2. The second relay coil '65 becomes deenergized, and the second switch 55 changes position to connect the third bias potential tap 53, furnishing a cut-off bias potential, to the grid 3|, whereupon the motor is stopped. The first switch 14 is maintained open at the same time, the spacing between the dog-contacting arms of the two switches of each set being such that both can be contacted at the same time by the dog in the limit position.

The system is now ready for a hoisting operation, which is initiated by manually changing the position of the hoist-lower switch 31 to the hoist position. The multi-polar switch I6 relay coil 24 is then energized, current to the motor M is reversed, and the third switch blade 23 thereof connects the hoist control network N| to the grid 3!. Since the hoist control limit switches E-i are both closed, the motor M proceeds to hoist the projector P at full speed. The upper dog D-I 6 controls the hoist control limit switches E'-l and network Nl to first reduce the speed of the motor M and then stop it when the flange J is firmly seatedin the upper limit collar V. At the sarne'time the lowerdo g D2 moves away from the lower controlfllimit switches E'2 permitting them to close, so that immediately after thesecond switch 15' of the lower control switches E2 hasclosedthe projector travelmay be reversed and the projector ,again'loweredif "desired. The hoist-lower control switch 3'! maintains'control at alltimesin tl'ie travel of the shaft S and projector P, and this travel'can be reversed at any time therein; an operator does not have to wait until a limit position has been reached.

Advantages of the system in accordance with the present invention; should'now be more apparent. In prioir systems where power to the hoist-lower motor is cut off just prior to the seating of the projector in its limit position, the projector coasts into a limit position. If the collars K are compressed too much, for example, in order to stop a water leak through the packing material W, friction between the packing material and theshaft S may be so great as to prevent seating of the projector in' its limit position. The projector may then not be sufficiently extended for proper use, or not sufiicien'tly retracted for tight seating, in which case a water leak eventually develops" due to vibration. On the other hand if powerto the motor is left on too long, the projector may be seated with violent force, in which case there may be jamming of the projector in a retracted or an extended position, or damage to the rack and pinion gears or to the flange and limit collars. By the present invention the projector is caused to creep. into a limit position, the motor power being sufilciently great to seat the projector against the resistance of a tight packing W, but not, great enough to burn out the motor M or jam the driving gears if the second switch [5 of either control switch group El or E-Z should fail to open. These latter switches 15 should be adjusted to open just at the limit point, but no; harm is done if they fail to open. Further, failure of one of these limit switches 15 to open has no effect on the reversibility of the hoist-lower operation.

Having now described my invention, what I claim is:

1. In a submarine listening apparatus carried and supported at the end of a shaft adapted to be extended through the hull of a vessel into the water, said shaft having limiting positions for retraction into the vessel and extension into the water, electric motor means, a gaseous conduction tube, means supplying power to said motor through said gaseous conduction tube, and switch means automatically operative when said shaft approaches a limiting position for causing said gaseous conduction tube to pass comparatively shorter power pulses while driving the motor in the same direction whereby the shaft creeps slowly to said limiting position.

2. In a submarine listening apparatus carried and supported at the end of a shaft adapted to be extended through the hull of a vessel into the water, said shaft having limiting positions for retraction into the vessel and extension into the water, electric motor means, a gaseous conduction tube having a grid bias control element, means supplying power to said motor through said gaseous conduction tube, and switch means power pulses and cause the shaft to said limiting position.

automatically operative when saidshaft reaches the vicinity of a limiting position forcontrollmg said grid element to provide a comparativelyhigher bias, whereby the'tube willpass shorter to creep slowly 3. In a submarine listening apparatus carried "and supported at the end of a shaft adapted to I be extendedthrough the'hull of'a vessel into the I water, said shaft having limiting positions for retraction into the vessel and extension into the water, electric motor means, a gaseousconduce tion tube having a grid bias control element,

means supplying power to said motor through said gaseous conduction tube,"switch' means in the circuit of said grid element; and switch con- 1 I controlling said grid element to provide a com- "paratively' higher bias when operated by said i switch control means, whereby thetube will pass shorter power pulses andcause the shaft to creep I slowly to said limiting position.

4.'In a submarine listeningapparatus carried and supported at the end of a shaft adapted to be extended through thehull of aves'selinto the water, said shaft having limiting positions for tube having a grid bias control element, means eous conduction tube, switch means inthe circuit'of said grid element, switch control means carried by said shaft positioned to operate said switch means when said shaft reaches the vicinity of a limit position, said switch means control-- lingsaid grid element to provide a comparatively higher bias when operated by said switch control I means, whereby the tube willpass shorter power pulses and cause the shaft to creep slowly to said limiting position, and second switch means in said circuit, disposed to be operated by said switch control means when said shaft is in said limit position, said second switch means controlling said grid element to provide a still higher bias when operated by said switch control means, whereby said motor is deenergized.

5. In a submarine listenin apparatus carried retraction intothe vessel and extension into the I water, electric motor means, a gaseous conduction supplying power to said motor through said gas gaseousconductmn tube, and switch means auto- ,rnatically operative when said member approaches a limiting position for causing said gaseous conductiontube to pass comparatively shorter power pulses wniledriving the motorin the same direc- I tion wherebysaidmotorcreeps slowly to said lim- I iting position, g

and supported at, the end of a shaft adaptedto be extended through the hull of a vessel into the I water, said shaft having limiting positions for retraction into the vessel andextension' into the water, electric motor means, a gaseous conduction I tube having agrid bias control element, means supplying power to said motor through said gaseous conduction tube; a sourceof negative bias,

potential for said grid, a potential dividerconnected between said sourceand the cathode of said tube;: a plurality of taps on saidpotential divider, of which a first tap provides a first bias 7 potential for conditioning said tube for full 1110- g tor speed, a second tap provides asecond bias potential for conditioning said tube for reduced motor speed, and a third tap provides a third bias potential forsubstantially cutting 01f said tube;

a pair of switch means controlling the connection I of said'taps to said grid, and normally connecting said first tap to said grid; and switch control means mounted on said shaft and disposed to,

operate one of said switch means to connect said 'secondtap tosaid grid in place of said first tap when said shaft approaches the vicinity of a limit position. I I p '6; Ethan apparatus having a member adapted means supplying power to said motor through said a EOR E L, DANFORTH- REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,031,573 Nauman July 2, 1912 2,163,632 Satterlee June 27, 1939

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