US2313165A

US2313165A - Mine lamp

Info

Publication number: US2313165A
Authority: US
Publication date: 1943-03-09
Anticipated expiration: 1960-03-09

Description

March 9, 1943. 6.0. NELMs ET AL MINE LAMP Filed March 9, 1940 4 Sheets-Sheet l G. c. NIIELMS ET AL 2,313,165

March 9, 1943. I

MINE LAMP 4 Sheets-Sheet 2 Filed March 9-, 1940 March 9, 1943. G. c. NELMS ET AL 2,313,165

MINE LAMP Filed March 9, 1940 4 Sheets-Sheet 3 March 9, 1943. G. c. VNELMS ET-AL 2,313,165:

MINE LAMP Filed March 9, 1940 4 Sheets-Sheet 4 Dyan r00 Us" M Patented Mar. 9, 1943 UNETE srrss s T OFFICE MINE LAMP Application March 9, 1940, Serial No. 323,224

27 Claims.

This invention relates toimprovements in mine lamps.

The rules established by the United States Bureau of Mines and other governmental agencies prescribe certain necessary features and capabilities of mine lamps before they'will be certified for service in' places, where combustible gases may accumulate. Thus, a requirement is made" that the head lamp should not only be safe against the presence at the outside of areas having different electrical potentials, but the structure should not be capable of direct manipulation by the miner so that such areas can be produced.

Further, it is necessary that such head lamps should be light, strong, free of projecting parts, and capable of manufacture and assembly at a low cost. Furthermore, it is preferred to provide a head lamp with two light sources which can be selectively employed, so that upon extinction of one atthe end of its life, the other may besimply and easilyenergized by the miner, who thus still has illumination for the remainder of his shift.

The present invention is concerned with a mine lamp which fits these conditions, and which the separated conditionof the structure has all exposed electrically supplied; parts at'a like polarity, or tie-energized. Further, thelampis; so constructed and arranged as to effect a de-energization of the source of light if the closing panel is shattered, or if the bulb of the light source itself is broken.

Another feature of the invention is the provision of switch means m association with a separable connector, by which thepositioning of parts of the separable comiector closes or opens the electrical circuit, and the separable connector includes structures which prevent the separation of its parts except when the circuit is broken.

A further feature of the invention is the provision of switch means in association with aseparable connector, whereby the connector itself is utilized for making and breaking selective circuits to the sources f Iight With' the inclusion of means for preventing the establishment of such circuits unless the separable parts of the connector are in a safe position, and effective likewise-to prevent separation of these parts-when a source of light is being energized.

Another feature ofthe invention is the provision of multiple switch means in association with a separable connector; in which interengag ing key parts are provided in the member" which i connected to the source of electricity; with ployment of a characteristic tool.

such a construction and arrangement that the key parts effect a closure of this switch when the separable members are moved into the current-delivering position, together with interengaging means on the members for preventing separation thereof while the switch is in closed position.

' A further feature of the invention is the provision of a separable connector, in which key parts are capable of engagement in a plurality of relative positions, together with switch devices connected therewith and; actuated thereby which establish proper operative; conditions at only one of the possible relative positions, whereby the separation of the-parts of the connector and an attempted manipulation 'ofa, key part to effect energization of terminal members will cause a false positioning of the said key part with accompanying difficulty of re-connection, and with the probability-that further movement of the key part to aposition for re-connection will prevent establishment of the proper operative conditions at the switch devices.

A further feature of the invention is the provision of a switch means in association with a separable connector, in which a switch is located in the member of" the separable connector which is in conductive relation with the source of electricity, and interengag-ingkey parts on the two members control the actuation of the switch, and in which protective structures enclose the key means on said one separable member and the key part itself is ofsuch shape that it cannot be moved to closed position without the em- With these and other featuresas objects in view, an illustrative formof practicing the invention is shown on the accompanying drawings, in which:

Figure 1 is a side View of" the head lamp and cord connector, with the headpiece in position on a cap and with the connector disassembled;

Figure 2.is a rear view of the same.

Figure 3 is a section substantially on-line 3-3 of Figure 2.

Figure 4 is an enlarged diametrical sectional view of the cable connector head, the partsbeing separated to show the elements of the assembly.

Figure 5 is an enlarged diametrical sectional view of the lamp holder and its connector member, the parts being separated to show the elements of the assembly.

Figure B'isa perspective view of theswitch and contact plates, the parts being separated to show the elements of the assembly.

Figure '7 is a perspective view of the same from the opposite end, the parts being separated to show the elements of the assembly.

Figure 8 is a top plan view of the lamp holder arm.

Figure 9 is an end View of the head lamp socket.

Figures 10 and 11 show diagrammatically the efiects of adjustment of the head lamp relative to the cap clips on standard miners caps.

The mine lamp according to this invention comprises a head piece H, a connector cord C and a battery B. The cord C is preferably fixedly secured and electrically connected to the battery at one end, and is provided at the other end with one member of a separable connection, the other member of this separable connection being comprised in the head lamp H. With this arrangement, the cord C can be separated from the head lamp H and plugged into an appropriate receptacle of a charging panel for the purpose of recharging the storage battery 13.

The head lamp structure H is illustrated as comprising the hollow body 29 which is formed by die pressing a plastic composition such as rubber or synthetic resin, to give it the proper form and thus provide a water and gas-tight body having a cavity 2| with its mouth at the front end of the body and having an aperture 22 which preferably is located at one side of the body and is comprised in a lateral extension from the general hemispherical shape (note Figure 2). A ridge 23 projects at the top and rear of thebody and provides a web 24 which is received between the apertured ears 25 of the cap loop-26. The cap loop 26 has a forwardly projecting stop member 27, and receives the securing means 29 through its apertured ears and through the aperture of the web 24, in such fashion that the ears are maintained in a resilient frictional relation with the web 24, while the

entire loop assembly

25, 26, 21 may be rocked about the axis of the pivot 28 to permit a range of adjustment of the head lamp upon the miners cap.

The side of the head lamp opposite the aperture 22, is provided with a pair of spaced ridges 29 having two apertures therethrough, the rearward aperture receiving a permanentpivot pin 39 about which a latch member 3| may rock. This latch member 3| has corresponding apertures. A wire seal S may be engaged through the alined forward apertures 32 as an efiective means to prevent accidental opening of the head lamp and to reveal the fact of such opening: a suitable seal may be made from a length of lead wire which projects beyond the ridges 29 at both its ends and has been flattened and widened at its ends by a suitable tool.

The front of the head lamp body 20 has screw threads 34 upon which may be threaded the bezel 35 which is provided with notches 35 into which the latch piece 3| may be engaged for preventing the unscrewing of the bezel 35. The mouth of the cavity 2| is normally closed by the panel 31 which may be of glass or similar material, and

. as shown in Figure 5. This structure includes likewise apertured and fits against the top flange a substantially gasand water-tight seal is provided by the soft rubber gasket 38.

A parabolic reflector 49 has a projecting flange which is seated upon the edge of the body 20, and has the locating projections 4| which extend into notches at the mouth of the body to hold this reflector against rotation about its axis. The reflector has an opening 42 in alinement with the aperture 22. V I

The incandescent lamp L is illustrated as of the two-filament type and has a glass bulb 45, the conductive base sleeve 46 with a pair of diametrically opposed base lugs 41, and the two base contacts 48 which are respectively connected each with one end of the filament, while the other ends of the two filaments are connected to the sleeve 46, in the usual way.

This lamp bulb is fixedly secured and tightly held in the body by a resilient arm structure,

a U-shaped support 59 formed of spring metal and has the upper portion 5| apertured to receive the lamp base sleeve 46 and provided with integral upwardly extending fingers 52 which extend along this base 46 and grip the same against rocking movement relative to the upper portion The lower portion 53 of the support 59 is 54 of a socket sleeve 55. The portion 53 and the flange 54 ar held fixedly together by spinning punching the edge of a metal retaining member 56 tightly in position to clamp these parts together.

It is preferred to reinforce and stiffen the upper portion 5| by turning its edge downwardly to provide a flange 58. A spring clamping member 59 of sheet metal is securedto the lower surface of the upper portion 5| by rivets 69, and extends within the flange 58. As will be seen from Figure 8, the fingers 52 are spaced apart, and the upper portion 5| is cut away to provide diametrically opposite notches 6| for permitting the base lugs 41 of the lamp to be pushed past the top portion 5| when inserting a lamp bulb, until these lugs engage the member 59. The lamp bulb can then be rotated about its axis, wherewith the resilient member 59 tends to force the lugs upwardly, and ultimately these lugs come opposite the downwardly arched portions 62 of the resilient member 59, and are held thereby so that the lamp bulb L occupies a predetermined position relative to the support at which its base contacts 48 are properly positioned for conductive association with the other parts of the structure.

The socket sleeve has an enlarged portion adjacent the flange 54, into which is received a disk 65 of insulating material, this disk being held in position by the lower portion 53 and the clamping ring 56 so that the assembly is immovably locked together, the lower portion 53, for this purpose, including an inwardly projecting locating tongue 66 which engages in a corresponding notch 61 of the insulation piece 65. Two contact points 68 (Figures 5 and 9) are provided in the insulating disk 55. With a two-filament lamp bulb, it is preferred to locate these contact points 68 at an angular separation of degrees with respect to the axis of the disk 65. At their upper ends, each of the contact points 68 is provided with a resilient contact piece 69 for engagement by a corresponding base contact 48 of the lamp bulb and each having a projection 69a engaged in a cavity 65a of the piece 65 for assuring maintenance of proper position. The insulating disk 65 also supports a key part '19 which maybe of cylindrical external form, and has an axial passage 1 preferably of triangular section: its upper end (in Figs. 3 and 5) is reduced and of square section for engaging in a corresponding hole in disk 65 to prevent rotation, and the extreme end is upset or beaten over to form a securing rivet head. Preferably the upper surface of this rivet head in its well, comprising a substantially axiallydirected portion and two end portions, these portions together forming a T-shaped slot 12-;

the contact.

The assembly of the support 50, socket sleeve 55, insulating disk 65, with their assembled structures including the clamping ring 56, may be constructed and assembled as a unit and inserted into the aperture 22 of the lamp bodyafter introduction into the cavity 2| It willbe noted that these structures, with the lamp bulb itself, comprise the entirety of electrically conductive elements within the head lampbody. The shoulder formation of this aperture 22 permits the reception of the successively enlarged portions of the sleeve 55 and clamping ring 55, while a lateral extension 22a of the aperture receives the bight of the support 50 and holds the entire structure against rocking about. the axis of the key part 10. When the parts have thus been assembled, an annular sleeve K (preferably of a hard, non-fragile synthetic plastic), and a securing ring are slipped over the lower end of the socket sleeve 55 and are. fixedly attached thereto by soldering, sweating, etc., dependent upon the nature of the material which forms the body 25. The sleeve K, preferably is of transparent material for at least the portion opposite the T slot 52, to provide a window for inspecting this slot, and fits the sleeve 55 closely and prevents spreading of the parts even with the presence of the T-slot.

The cord C is preferably of the type which has two insulated conductors. At the end of. the cord which is to be fitted to the headlamp, a ferrule 86 is crimped over the cord, with inwardly projecting ribs to assure a transfer of tensile stresses to the cord without stripping of. the. ferrule 80. A metal sleeve 8| is then slipped over this ferrule and these parts are secured together by soldering, one of the conductors. 82' of the cable C being brought between theparts 80, 8|, and likewise secured electrically to these parts by soldering. The portion of the sleeve 8| which engages the ferrule 80' is of reduced, diameter, and a conical portion connects this end with an enlarged upper .end, with a transition shoulder 83. The enlarged upper end has a pin-like projection 84 for interengagement with the T-shaped slot 12 of the socket sleeve 55 and thereby determines the relative orientation of the parts of the separable connection.

The enlarged part of the sleeve receives an inner sleeve 85, which is of insulating material and has diametrically opposed external grooves 86 for locating engagement by the tongues 81 on the sleeve, whereby to determine the desired relative angular position of these parts, and also to hold the insulating sleeve in assembled position. The insulating sleeve 85 has a pair of grooves 89'at its inner surface, in'predetermined angular position relative to the grooves 86.

A cup-shaped member 90 is fitted fora guided sliding movement in the insulating sleeve 85, and is provided with outwardly projectingbosses 95 which are received in the grooves BQforlOcating this member 99' and limiting its relatively outward movement. Themember 99 has an inwardly extending flange 92 whichhas guiding apertures SStherein, two being provided in the illustrated form; and also-has a central aperture 93a which is of s-ufiicient size to loosely pass flange 95 provided with the projecting pins 95,

which are two in number in this preferred form and which can slide in the apertures 93. The sleeve 94- loosely receives the key part Hi. A coil spring 91 bears against the lower surface of the flange 95' and presses the plunger into contact with the flange 92, with its pins-95 fully extended through the apertures 95 so that they provide contact points. The thrust of the opposite end of the spring 9? is received by a switch plate 98 which is formed at its upper face with a key part 95 which preferably is. of triangular section and fits closely in the triangular passage ii: of the key part Hi. The switch plate 982 is rotatable within: the insulating sleeve and is illustrated as provided on its lower face with four contact points iilfl which are spaced apart at 'degrees and have a uniform radius from the axis (Figure '7).

An insulating disk I G I' rests against the shoulder 83 at the bottom of the enlarged portion of the sleeve BI, and supports a conductive metal disk m2 at its upper surface. This disk I52 is cut away so that the four insulating projections Hi3 of the insulating disk I01 may extend therethrough, each of. these projections preferably having a central cavity for receiving a corresponding contact point Hi0 and affording resistance against accidental displacement thereof, the cavity being extended by a small bore through the disk NH which prevents accumulation of dirt in the cavity; The actioniofthe spring 9'! and the conformation of the contact .points Hit), of the projections IE5, and of their cavities, assures proper positioning and main tenance in the on and oil conditions. The disks H35, H32 also have a central aperture we throughwhich extends the second conductor I05 of the cable C, this conductor end W5 being soldered to the disk N12. The disk It has a notch l55a, at its edge for engagement. with a locating projection lflt of the sleeve 81.

It will be noted that the assembly of the plug member at the end of the cable may be easily effected, while retaining the parts in the desired relative positions of orientation, by slipping the assembly of disks NH. and I'll2into the sleeve 8|, rotating them until the notch lll5a fits over the projection Hi6; then inserting the switch plate. 98 and the spring 97; and then pressing a preassembly of the insulating sleeve 85', guiding member Stand plunger 94', in a position over the spring, while introducing a properly shaped tool to engage the key part 99" and hold the switch plate 93 in centralized position so that the sleeve 85 may be pushed around it, in order that thesleeve 85 will insulate the switch plate 98 from the sleeve 89. Itv will bev noted thattheengagement of the pins 96 in the. apertures 93., the. engagement of the projections 91 in the. grooves 89, and. the engagement of the grooves 85 with the tongues 87, all cooperate to assure. proper orientation of the corresponding.structures. When the assembly has been completed, it is assured by prick-punching the tongues 87; A tight-fit ting rubber protective jacket R is employed to enclose the connector structures except. for the enlarged portions thereof which-normally are received within the head-lamp structure.

The operation of the structure is as follows:

,When the. lamp is. employed in ,coal mining, it iscustomary-for' the mine operator to provide a lamp house which is provided with equipment for charging the batteries. For this purpose, any suitable construction may be employed which has receptacles for receiving the upper portions 8| of the plug member at the end of the cable C, and preferably also has a key part corresponding to the key part in for effecting a closure of the switch means within this plug member, by engaging the key part 99 and rotating the switch plate 98. The batteries are normally supplied with water, etc., by an attendant while the miner is off-shift, so that the battery is in proper condition for later employment.

By the present arrangement, the miner can enter the lamp house and take his individually marked battery from the rack, by eiiecting a disconnection of the plug member from the charging receptacle, wherewith the key parts will effect a movement of the switch plate 98 into the open position. The miner can assemble the lamp with the head piece himself. This is done by simple direct operations, comprising the insertion of the upper end 8| of the plug member into the socket sleeve 55. This can only be accomplished in one relative position of the parts, in which the projection 84 engages in the axial portion of the T- slot 12. In this relative position of parts, however, the triangular passage in the key part I9 is alined with the correspondingly shaped key part 99, so that these key parts telescope together. The projecting pins 96 ultimately engage against the lower surface of the insulating disk 65, but effect this engagement at points of this disk of which one is separated by degrees from the contacts 58 of the disk 65, whil the other contact point 96 is naturally 180 degrees spaced from the first contact point 96. It will be noted that no current flows during this portion of the assembly, as the switch plate 98 is presenting its contacts I99 in the cavities of the insulated projections I93, and the contact points 96 are not engaged with the contact 68. As the plug sleeve BI is ushed inward, the contact points 96 are depressed, against the action of the spring 91 until the projection 84 comes opposite the lateral portions of the T-slot I2. The miner can then rotate the plug about the common axis so that the projection 84 will enter one or the other lateral portions of the T-slot I2. This can be visually observed through the transparent ring K, which also permits the miner to assure himself that the parts are in proper positions at each step of the operation. This rotation is limited to substantially 45 degrees in the selected direction, and at the end of this movement one of the contact points 96 will engage with a contact 68, while the engagement of the key parts 10, 99 has effected a rotation of the switch plate 98 until contacts 400 thereof are in conductive relation with the member I92. Thus the two switches are closed, and current can flow to one of the spring members 69 and thus to the selected flament in the lamp bulb 45 for energizing the same.

In this position of parts, it will be noted, the engagement of the projection 84 in the T-slot I2 prevents separation of the plug member at the end of the cable C from the socket member which is formed rigidly withthe head piece.

The lamp is now illuminated, and the miner can place the headpiece in his cap and place the battery in an appropriate carrying structure.

If during his shift, the selected filament should burn out, it is only necessary for him to seize the rubber protecting jacket R and rock it with the plug member at the endof the cord C about its common axis with the sleeve member 55, so that the projection 84 passes into the other lateral portion of the T-slot 12, whereby the switch plate 99 will be rocked through a total angle of degrees, thuspassing a point of de-energization and attaininga final position of restored energization. Likewise, the contact point96 which has been in energized relation with a contact 68 will be moved through the same'angle of 90 degrees, through a condition of opening the circuit, until it attains the final position in which it engages the other contact 68. Thus, a new circuit arrangement is set up in which current will flow to the other filament and the miner will continue to have illumination for the remaining period of his shift. It will be noted that this can be effected without separating the parts, and without the provision of any separate switch structure or switch operating device.

When the miner returns from his shift below, he replaces the battery in the charging rack in the lamp house, and separates the cord from the head piece by rotating the plug member until the projection 84-is alined with the axial portion of the T-slot I2, whereupon the members can be separated by an axial movement. In rotating the plug and socket members relative to one another the switch plate 98 is turned through an angle of 45 degrees so that the contacts I99 again lie over the insulation projection I03, and also the contacts 96 restagainst portions of the insulating disk ,65 which are spaced from the contacts 68. It will be noted that the provision of the switch means within'the terminal structure at the end of the cord C, with the interengaging key parts I9, 99, and the interengaging means 84, 12, assure that the switch will always be open in the condition where the parts may be separated, and therewith the exposed conductive areas'are at the same potential, being that determined by the conductor 82 in the cable C, whereas the conductor I05 is not connected with any exposed conductive areas. a

The cord plug can be introduced into a receptacle on the charging rackwhich has a socket sleeve corresponding to sleeve 55 and a key part corresponding to key part III. Upon rotating the cord plug as before, amaintained mechanical engagement is effected, and a contact pin 96 engages a charging contact corresponding to contact point 68, and charging begins.

The triangular shape of the key part 99 and its location in a protected position beneath the flanges 92, 94, prevents its being operated without the employment of a characteristic tool. For example, thin pliers or pieces of metal will not establish a sufficient grip to' rotate it, because of the frictional resistance to rotation which is produced by the spring 91, and by the engagement of contacts I99 in the cavities of the projections I03, and also because of its peculiar shape. It is difficult to introduce any tool through the flange 94 alongside the key part 99, and further it will be noted that-the shape of the switch plate 98 with its Widely spaced contacts I90 prevents any rocking of this plate about an axis established by two adjacent contacts I09, in such a way as to bring any part of this structure into conductive relation with the disk I92.

2 Further, if the key part 99 is'partially rotated, 1t W111 not be in position to enter the corresponding part 10 of the socket. In particular, due to the employment of a movement of 45 degrees for closing the head piece contacts, and a correspondng movement of the switch parts in the cord terminal structure, and the necessity of accurately selecting andpositioning. the. key for the proper one of three positions which are spaced 120 degrees apart, the usual result of tampering with the cord terminal switch is the production of a condition in which the miner is unable to reconnect his lamp properly, and not only must lose his shift but must report the result of the tampering so that a resetting can be accomplished to permit recharging. Thus, the provisions of a different number (here three) of relative posi tions of mechanical engagement of the key parts from the number (here four) of positions in which the uniformly spaced contacts IEO may make proper engagement, any attempted movement of the key part 99 during separation of the connector will probably lead to a false positioning at which proper lighting and charging are prevented. At the same time, the structure permits easy inspection of the proper positioning of parts, as the customary inspection before starting shift to ascertain that each filament can be lighted, will immediately show any false positioning, even assuming that it has not been noted and corrected by the lamphouse attendant while servicing and observing the charging rate.

The lamp bulb can be easily exchanged, in case of breakage or burn-out, by breaking the seal S which is engaged in the apertures 32, and swinging the latch 3| from the relative position shown in Figure 3, and then unscrewing the bezel 35 in the usual way. The lamp bulb- 45 can then be rotated about its axis, with a yielding of the spring 59, until the lugs 41 of the lamp bulb base 45 come opposite the notches 6| whereupon the base may be pulled outward by relative axial movement. A new bulb can be inserted by a reverse operation, followed by the application of a new seal through the apertures 32.

If the panel 31 is of glass, and is ruptured, so that the lamp bulb is permitted to rock relatively forward and upward under the urgency of the

U-shaped spring member

50, 53, the base contacts 48 of the lamp bulb leave the spring contacts 69 on the insulating disk 65 and interrupt the circuit through the filaments. Similarly, the circuit will be open in the event of a breakage of the glass bulb 45, so that the lamp becomes deenergized and a residual burning of the filaments while exposed to ignitible gas does not occur.

As shown in Figs. 10 and 11, mine lamps are customarily employed with miners caps which have the visors V (Fig. 10) or V (Fig. 11); and having the cap clips I39. The cap clip. is secured to the front of the cap at the structure which is substantially upright when the cap is worn. The visor V or V is designed by the manufacturer of the cap, and several different patterns are in widespread use, but have the common characteristic of substantially the same extension in front of the forehead of the miner and serving to protect his eyes against falling particles. Illustrative forms are shown in Figs. 10 and 11.

The provision of. the present pivot means 28 between the

loop assembly

25, 26, and the web portion 2 1 of the body permits regulation of the direction of projection of light. The light rays are projected in a substantially conical beam from the lamp bulb and reflector, being limited by the bezel ring and other front closing devices. deretofore, mine lamp headpieces have included rigid cap loops which are so directed relative to the axis of the beam of light as to give illumination upon a Working face at a normal working position and distance. This represents a compromise; and frequently means a lack of sufficient light at a desired point unless the miner holds his head in an uncomfortable position. For example, such a condition may give a beam 0, c as in Figs. 10 and 11, in which a part of the light is cut off by the visor, and lost; and the ray 0' shows that the lower part of the illuminated field is determined by the relative positions of the light source and the edge of the visor. According to the workv to be performed, however, the miner often desires to have the beam projected in a particular direction: for example, the motorman of a trip of cars desires to have a substantially horizontal beam directed parallel to his. normal line of vision, while a miner engaged in shoveling coal or other material prefers to have the aXis'of the beam relatively lower, to illuminate the ground near his feet, and is not so concerned with distant illumination. As shown in Figs.v 10 and 11, in the upward rockedposition of the headlamp, this cone of light as illustratively represented by the lines a, a, has a substantially horizontal axis when. the cap is in normal position on the head, and the miner is holding his head erect: and in this position the beam has. its center substantially parallel to the normal line of. sight. When the headlamp is rocked, so that the conical beam passes through the area indicated by lines 17, b in Fig. 10, more of the immediate foreground is illuminated, and with this particular setting for the cap shown in Fig. 10, the conical beam just touches the edge of the visor V. It will be noted that the lamp in this position. gives an illuminated field closer to the miners feet than can be obtained in the further rocked position in which the beam is projected through the area a, c, as in the latter position the lowest ray 0 strikes the ground beyond the lowest ray b.

In the form of Fig. 11, a rocking downward from the position of lines a, a to the position of lines 12, b similarly gives a circular field of illumination in front of the miner, while a rocking to the position 0, c is one in which the conical beam is partly intersected by the visor V, and the ray 0 determines the point nearest the miners feet which can be illuminated for a given position of his head.

As a conical beam normally provides a circular illuminated field, it will be noted that the adjustment permits the. direction of this field in an optimum manner for the necessities and desires of the particular miner. Further, it is found that this adjustment permits the utilization with maximum eificiency of a single model of headlamp with the various models of miners caps.

It will be understood that the construction described is the preferred form because of the relative simplicity and ease of construction and assembly of the parts; and that many changes may be made therein without departing from the scope of the appended claims.

We claim:

1. A mine lampincluding a head piece, a current-supply cord, a separable connector for joining the head piece and cord, said separable connector including means providing interengageable electrical contacts and mechanical elements effective in a selected relative position thereof for preventing accidental separation of its parts, and switch means including parts on the head piece and on the connector for closing theelectrical circuit from the cord to the electrical contacts when the said elements are in position for preventing accidental separation and for opening said circuit before said elements are in position for permitting separation.

2. A mine lamp comprising a head piece having a light bulb with a plurality of filaments, a supply cord, separable electrical connector means having parts on the head piece and parts on the supply cord, said parts being assembled by relative sliding movement, said parts including locking elements which are engaged by a relative rotation of the parts when in assembled position, and switch means actuated by the said relative rotation for closing an electrical circuit through the cord and a selected filament, said switch means including structures for closing and opening the circuit at a point between the supply cord' and the electrical connector means.

3. A mine lamp comprising a head piece, a conductive cable for supplying current to the head piece, interengaging members on said cable and head piece including a plug member and a socket member, a key part in one said member and a mating hollow part in the other member for interengagement when the plug member is in the socket member, one of said parts being fixed to its corresponding member and the other said part being rotatable relative to its corresponding member, a repressible and a fixed contact on one member, a contactor on the other said member engageable by said repressible contact upon relative rotation of said members, a switch plate connected to said rotatable part and rotatable therewith and having a contact piece arranged to be engaged by the fixed contact at a predetermined relative rotated position of the switch plate and its corresponding member; and interengaging elements on the plug and socket members for causing said repressible member to be forced inward during a relative sliding movement of said members and for locking the members upon a relative rotating movement thereof after the said repressible member has been forced inward, said rotating movement being effective through the key and hollow parts to move the switch'plate to establish electrical conduction between said switch plate and fixed contact at the time of establishment of electrical conduction between said repressible contact and said contactor.

4. A connector and switch structure for mine lamps and like devices where: the current-carrying contact must be de-energized in a disconnected condition of the parts, comprising separable members connected to the source of current supply and to the load, said members including a plug and a socket constructed and arranged for interengagement, first switch means including contacts on the plug and socket which are brought into conductive relation upon relative rotation of the members; second switch means located on one of said members; a key part and a mating hollow part, one said part being located on the plug and the other part on the socket so that the parts are interengaged during the entry of the plug into the socket, said second switch means including a rotatable switch plate connected to one said part so that said second switch means is closed upon said relative rotation of the members, and interengaging means on said members for preventing separation thereof while said switch means are closed.

5. A combined switch and separable connector structure, comprising a socket and a closely fitting plug, said plug being slidable into said socket and rotatable therein, said socket having a part for receiving a control key; said plug having a sleeve guidedly engaged with the socket wall, a first conductive member in said plug and having at least one contact point extending beyond the end of the sleeve in one position of said conductive member, a second conductive member in said sleeve having a key part thereon for engagement in said key-receiving part when said plug and socket are brought together, a spring located in the sleeve between said conductive members for pressing the first conductive member toward said one position, said second conductive member having an eccentric contactor on its face opposite the spring, a cooperating contact fixed to and insulated from the sleeve and eccentric to its axis for engagement by said contactor, said parts cooperating when the engaged plug and socket are relatively rotated for causing said contactor to engage said cooperating contact; said socket member including a contact point for engagement by the contact point on the first conductive member; and interengaging means on the plug and socket for preventing separation thereof while said contactor and contact are engaged.

6. A structure as claimed in claim 5, in which the key part is of triangular cross-section and the key-receiving part has a thin wall about a mating triangular hole, the end of the key part terminating at a substantial distance inward of the outer end of the sleeve, and in which the first conductive member has an aperture very little larger than the key-receiving part for receiving the same whereby operation of the key except by a characteristic tool is rendered difficult.

7. A combined switch and separable connector structure, comprising a socket and a plug, said plug being slidable into said socket and rotatable therein; said socket member having a conductive socket sleeve, a contact pin, and a central key-receiving part; said plug having a plug sleeve closely fitting said socket sleeve, an insulating sleeve in said plug sleeve, a guide flange fixed at the outer end of the insulating sleeve having a central aperture for passing said key-receiving part and having a further aperture, a plunger piece guided in said insulating sleeve and having a contact pin extending through said further aperture and guided by the wall thereof and also having a central opening for passing said key-receiving part, a relatively rotatable switch plate having a key part for engagement with said key-receiving part when the plug is inserted in the socket and cooperating therewith so that said switch plate and socket sleeve move together relative to said plug sleeve, a spring between the plunger and switch plate, a contactor on the face of the switch plate opposite the spring, a contact assembly secured at the inner end of the plug sleeve for engagement with the contactor at a relatively rotated position of the switch plate and plug sleeve; interengaging means on the socket and plug for predetermining the permissive relative positions thereof at which they may be slidably engaged and for holding the same against sliding separation when they occupy a relatively rotated position.

8. A combined switch and separable connector structure, comprising a socket and a plug, a contact point in the socket; a first characteristic key part on said socket, a second and cooperative characteristic key part on said plug, a plug sleeve surrounding and extending beyond said second key part and including a flange extending partly across the sleeve cavity in which the second key part is located, a switch including 2,813,165 elements fixed to the plug and elements fixed to the second key part, said elements being located in and protected by the plug, and a contact point for engaging the socket contact point; interengaging means on the plug and socket for predetermining the permissive relative positions thereof at which they may be slidably engaged and for holding the same against sliding separation when they occupy a relatively rotated position.

9. A combined switch and separable connector structure, comprising a socket member and a plug member having interengageable contacts; one of said members including a housing, a switch including an element fixed to the housing and an element rotatable relative to the housing; interengageable means on the socket and plug for predetermining the permissive relative positions thereof at which they may be slidably engaged and for holding the same against sliding separation when they occupy a relatively rotated position; conductor means connecting said switch and the contact on said one member in series; and interengageable key parts fixed on the relatively rotatable switch element and on the other said member for producing a closing of the switch during relative rotation of the said members while engaged together and for producing an opening of the switch while the said members are being relatively rotated into position for sliding disengagement, whereby the contact on said one member is de-energized prior to the complete separation of said members.

10. In a mine lamp including a current supply means, a head piece, and a light bulb in the head piece, the combination therewith of means for conducting current to said bulb comprising a plug and a socket with an interengaging bayonet slot in the socket and a pin element on the plug, and including a switch for controlling the flow of said current, said plug having an externally accessible portion for operating said switch during movement of the pin in the slot, a reinforcing sleeve surrounding the slot, said switch having an indicator part located within the head piece for showing the prevailing position of the switch, and a transparent element comprised in said sleeve opposite said indicator.

11. In a separable connector structure for employment between a source of current and a load, cooperative plug and socket members connected to the source and the load, said plug member having a pin and said socket member having a bayonet slot, said pin and slot being effective for controlling the relative movements of said members while engaged, switch contacts carried by said members for engagement upon relative rotation thereof whereby to connect the source to the load, and a sleeve surrounding said socket member for reinforcing the same at the region of the slot, said sleeve including a transparent portion opposite the inner end of the bayonet slot for permitting inspection of the position occupied by said pin.

12. A mine lamp comprising a head piece, a current supplying cord including a terminal end; interengageable connector parts on said head piece and terminal end and including a conductor sleeve having a bayonet slot on one said part, a plug member on the other said part having a locating pin engageable in said slot, and

contacts on said parts positioned thereon to be in conductive engagement when said locating pin is engaged in and detained by said slot; and an annular transparent member surrounding, said conductive sleeve for permitting inspection of the position of said locating pin and in closely embracing relationship with the sleeve to prevent spreading of the same.

13. A mine lamp comprising a head piece body of insulating material with a cavity open at the front and closing means therefor including a transparent panel, said body also having an aperture, a bulb having a filament which must be oriented for optimum illumination, a bulb holder assembly comprising two cooperative resilient members for holdin a lamp bulb at a predetermined position and orientation, said body including means engageable with the assembly for assuring the proper orientation of the same, a conductive sleeve structure in said aperture and fixedly connected to said members at its inner end, an insulating member supported in said sleeve, contact means carried by said insulating member for engagement by contact means on the lamp bulb, said assembly being capable of insertion and removal as a whole, and means outside the body for securing said assembly in position.

14. A mine lamp comprising a head piece body of insulating material with a cavity open at the front and closing means therefor including a transparent panel, said body also having an aperture, a lamp bulb having a filament which must be oriented for optimum illumination, a bulb holder assembly comprising two cooperative resilient members for holding a lamp bulb at a predetermined position and orientation, said body including means engageable with the assembly for assuring the proper orientation of the same, a conductive sleeve structure in said aperture and fixedly connected to said members at its inner end, an insulating member for engagement by contact means on the lamp bulb, said assembly being capable of insertion and removal as a whole, and means outside the body for securing said assembly in position; said bulb and assembly constituting the entirety of electrically conductive parts mounted within the body.

15. A separable electrical connector for connecting a source of current with a load, comprising members having interengageable mechanical elements which prevent direct separation upon completed engagement and electrical contacts for establishing an electrical circuit upon completion of engagement, and switch means located between the source and the contacts and actuated during the course of engagement for closing a circuit and during the course of disengagement for opening the circuit, said elements-and switch means including key parts having a predetermined number of relative positions in which mechanical engagement may be effected and including also a difierent number of uniformly spaced switch contactors which are properly engaged in the course of mechanical engagement in only one of said relative positions of the key parts.

16. A separable electrical connector compris ing a plug member and a socket member, one of said members being arranged for connection to a source of current and the other for connection to a load, said members being assembled and separated by relative sliding movements, said members including locking elements which are engaged by a relative rotation of the members when in assembled position and also including electrical contacts for completing a circuit upon said rotation, and a plurality of separate switch means connected electrically in series and actuated by the said relative locking rotation for closing an electrical circuit through the connector and actuated by an unlocking rotation for opening said circuit before the members attain a position for sliding separating movement, one of said switch means being located between the source and said electric contacts whereby the contacts are deenergized when the members are in position for separation.

17. A combined switch and separable connector structure for employment between a source of current and a load comprising a socket member and a plug member, interengageable electrical contacts on said members for selective-switching engagement upon relative rotation, interengageable mechanical elements on said members for permitting sliding introduction of the plug member into the socket member and effective for looking said members against sliding separation upon relative rotation thereof, and a switch element located between said source and said interengageable contacts and actuated upon such relative rotation for closing and opening the circuit from the source to the contacts whereby the contacts are disconnected from the source when the members are in position for separation.

18. A separable electrical connector for em ployment between a source,of current and a load comprising a plug member and a socket member, said connector being assembled and separated by relative sliding movements, said members including locking elements which are engaged by a relative rotation in either direction when in assembled position, first switch means in one member actuated by said relative locking rotation in either direction for closing an electrical circuit through the connector, and further switch means in series in said circuit and including contacts on the other member for selective engagement by said relative rotation in one or the other direction, said switch means being actuated into open position by a relative unlocking rotation of the elements before the elements attain a position for sliding separating movement of the members, said first switch means being located between the source and said electrical contacts whereby the contacts are de-energized when the members are in position for separation.

19. A mine lamp comprising a headpiece having a sleeve open to the exterior; a plurality of insulated contacts at the inner end of the sleeve, said contacts being spaced from the sleeve wall and the sleeve axis, and a plurality of lamp filaments selectively connected to said insulated contacts; a conductive cable for supplying current to the headpiece, a plu attached to an end of the cable and insertable into said sleeve, and a plunger in said plug having at least one repressible contact projecting at the end of the plug member eccentrically of the axis thereof for selective engagement with said insulated contacts; interengaging locking parts on the sleeve and the plug effective for permitting a sliding engagement thereof and thereafter a rotating relative movement thereof in either direction when the plug is in operative introduced position in the sleeve and effective upon such relative rotation in either direction to prevent separation of the plug from the sleeve, said insulated contacts being so positioned in the sleeve that the repressible contact does not engage any insulated contact during the sliding engagement of the sleeve and plug and that the repressible contact is engaged only with the selected one of said insulated contacts at the completion of said relative rotation whereby the plug is effective as a switch for determining the energization of the selected filament only.

20. A mine lamp comprising a headpiece having a cavity and a transparent panel closing said cavity, a sleeve supported in the wall of the headpiece, a first blade-spring conductor member secured to said sleeve member and extending into said cavity, the inner walls of the headpiece being positioned for holding the first conductor member against movement about the axis of the sleeve and thereby compelling the same to rock in an are substantially at a right angle to said panel, means on said first conductor member for fixedly receiving a lamp bulb base and resiliently rockable with said first conductor member, a second spring conductor member insulatedly carried by said sleeve and extending into said cavity opposit said first conductor member whereby the engagement of said panel with the lamp bulb will cause said first conductor member to rock resiliently until the base contact of the lamp bulb is resiliently engaged with the second conductor member, and conductor means for energizing said conductor members, said first conductor member being effective upon breakage of the bulb or panel or removal of the latter to move the bulb base and thereby disconnect the circuit.

21. A mine lamp comprising a headpiece having a cavity and a transparent panel closing the cavity, a sleeve member supported in the wall of the headpiece, a first blade-sprin conductor member secured to said sleeve member and extending into said cavity, the inner walls of the headpiece being positioned for holding the first conductor member against movement about the axis of the sleeve and thereby compelling the same to rock in an are substantially at a right angle to said panel, said first conductor member having a resiliently rockable arm, said headpiece having parts for compelling said arm to rock toward and from the mouth of the cavity and effective to prevent rotation of the first conductor member about the axis of the sleeve, means on said arm for fixedly holding a lamp bulb base, a second resilient conductor member located in the path of movement of the lamp bulb base, and means for securing said panel in position for closing said cavity, said securing means being effective for pressing said panel against the lamp bulb in said holding means so that a base contact of said lamp bulb is in conductive engagement with said second conductor'member, whereby breakage of the panel or glass bulb will permit the arm to move the bulb base resiliently toward the mouth of the cavity and interrupt said conductive engagement.

22. A mine lamp comprising a headpiece having a cavity, a transparent panel, means for securing said panel across the mouth of the cavity, a sleeve in said headpiece, a spring conductor having one arm attached to said sleeve, said conductor having a second arm at an angle to said one arm and extending into the cavity and rockable resiliently toward and from the mouth of the cavity, the headpiece having portions of its inner walls lying close to the edges of the spring arms at said angle for compelling the rocking movement of said second arm to occur only in directions toward and from the panel, the second arm being apertured adjacent its free end for receiving the base of a lamp bulb, means on the second arm for causing said lamp bulb to move with the second arm, an insulating piece in said sleeve, and a second conductor member mounted on said insulating piece and located in the path of movement of the lamp bulb base, said securing means being effective for causing said panel to engage and hold the lamp bulb in a position in which the base contact thereof is in conductive engagement with said second conductor member, said spring conductor being efiective upon breakage of the panel or glass bulb to cause the second arm to move the bulb base resiliently toward the mouth of the cavity and thereby interrupt said conductive engagement.

23. A lamp bulb holder for a mine lamp, comprising a headpiece having a cavity, a sleeve in the wall of the headpiece, a conductive spring member of U-shape having one of its ends secured to the inner end of said sleeve, the other end of the spring member having an aperture for receiving the base sleeve of a lamp bulb, said base sleeve having a sleeve lug and a base contact, spaced lugs integral with said spring member extending along the lamp base sleeve for holding the bulb against rocking relative to the spring member, a resilient blade-spring member for engaging the sleeve lug of the lamp bulb and pressing it against said spring member, an insulating member supported by said sleeve, and a contact member carriedby said insulating member and positioned opposite the base of the lamp bulb for engagement with the base contact.

24. A lamp bulb holder for a mine lamp, comprising a hollow insulating body, a conductive sleeve mounted in the wall of said body, a conductive spring member oi U-shape fixedly secured at one of its ends to said sleeve, the spring member projecting radially beyond the sleeve, the body having portions located adjacent the edges of the spring member to prevent rotation of the sleeve and the spring member about the axis of the sleeve, the other end of the spring member having an aperture substantially coaxial with the sleeve for receiving the base sleeve of a lamp bulb, said base sleeve having a sleeve lug, spaced lugs integral with said spring member extending along the lamp base sleeve for holding the bulb against rocking relative to the spring member, and a resilient blade-spring member for engaging the sleeve lug of the lamp bulb and pressing it against said spring member, said members including means for arresting said sleeve lug at a predetermined position of relative rotation of the buib and spring member.

25. A lamp bulb holder comprising an insulating body, a sleeve mounted in said body, a conductive spring member of Ushape having apertures in its ends, said apertures being substantially on a common axis with the sleeve, one end of said member being connected to the sleeve, the other end of the spring member having spaced lugs integral therewith and extending from the aperture thereat to receive and support the lamp base sleeve of a lamp bulb having a sleeve lug and an eccentrically positioned base contact, said lugs being effective to prevent rocking of the lamp bulb relative to the spring member, a resilient blade-spring member for engaging the sleeve lug and pressing it against said spring member, said members including means for arresting said sleeve lug at a predetermined position of relative rotation about said axis, and a. contact member positioned eccentrically to said axis for engagement with said base contact when said sleeve lug is held by said arresting means.

26. A miners lamp assembly comprising a battery, a headpiece including a lamp bulb, and a cord connecting the headpiece and battery, and in combination therewith a switch having a rotatable member having a first characteristic conductive key part thereon, relatively movable first and second contacts of which said first contact is electrically connected through the cord with the battery and the second contact is connected to the said first conductive key part, a separable secondand cooperative characteristic conductive key part slidably engageable in said first key part and effective for producing a rotation of said rotatable member upon relative rotating movement of the second key part and the said first contact, and means preventing sliding separation of the key parts, when in their relatively rotated circuit-closing position, for compelling a relative rotation before the parts can be separated and thereby opening the circuit connection from the battery to said first key part so that the said first key part is deenergized when the parts are separated.

2'7. A combined switch and separable connector structure, comprising a socket member and a plug member, interengageable electrical contacts on said members, interengageable mechanical elements on said members for permitting sliding introduction of the plug member into the socket member and effective for locking said members against sliding separation upon a first relative rotation thereof whereby the members may only be separated upon a second relative rotation, a switch element located in one said member, a key part on said one member and connected to said switch element, and a second key part on the other member, said key parts being slidingly interengaged during said sliding introduction and cooperating during said first relative rotation to close said switch element, said key parts being eifective upon said second relative rotation to reopen said switch element whereby the contacts of the said one member are not at a poten tial difference when the members are separated.

GEORGE C. NELMS. EARL J. COGGESHALL. EARL A. BERRY. WILLIAM K. WILBUR.