Improvements in Electric Connecting Devices, applicable to Lamp- holders, Wall Plugs, and the like.
Year: 1897

page_text: PROVISIONAL SPECIFICATION.
Improvements in Electric Connecting Devices, applicable to Lamp-
holders, Wall Plugs, and the like.
I, CHARLES LUDWIG RUDOLPH ERNEST MENGES, of Balistraat, The Hague, in
the Kingdom of Holland, Electrician, do hereby declare the nature of this inven-
tion to be as follows:-
•
This invention relates to improvements in electric connecting devices, applicable
to lamp-holders, wall plugs and the like, it being a feature of this invention
that the fastening is obtained by screw action, while however the plug of the
ordinary bayonet holder may be employed.
The essential characteristic of this invention is that the holder is provided with
a movable sleeve having helical surfaces or slots with which the projecting pins
on the plugs engage, so that by turning the plug while its end face bears upon the
contacts in the holder, it screws the sleeve up so as to compress or extend a spring
with which the latter is provided, thus pressing together the contacts for the
transmission of the current.
In order to prevent the plug from turning back again of its own accord, small
recesses are formed at the extremities of the said helical surfaces, which to a
certain extent act as oppositely inclined screw-threads and tend under the action
of the aforesaid spring to cause the plug to screw itself still further in without
however rendering it impossible to un-screw the same by hand.
Owing to the fact that in my improved connecting devices the transmission of
the current is effected not by means of small springs as is the case with the
ordinary bayonet-joint sockets, but by means of substantial contact surfaces or
terminals, the said connection is in this respect well adapted for safety fuses and
for use with large currents while moreover the making of a good contact is not
dependent upon any manipulation in the insertion of the plug and the latter cannot
become loose of itself.
In my improved connecting devices the advantages of the ordinary screw-
connection and of the bayonet-connection between the socket and plug are combined,
whilst the disadvantages of both are obviated. In addition to this, my improved
devices possess the advantage when employed for safety fuses that the insertion
of the wrong plug, that is to say a plug for too high or for too low a strength
of current, can be prevented by providing the sockets with deeper helical surfaces,
or with special slots, the plugs for the different strengths of current having their
pins so arranged, that they will only engage with the surfaces or slots of the
sockets to which the said plugs properly correspond.
According to the arrangement of the contacts between the socket and plug the
device may serve for various purposes. For instance if the two helical surfaces
are not included in the circuit, the device may be used for incandescent electric
lamps, for single pole safety fuses, for two wire connecting plugs and the like.

page_text: Referring to the accompanying drawings in which all the figures are perspective
views,
Figures 1 and 2 show respectively the plug and holder of an electrical connect-
ing device having my invention applied thereto..
Figure 3 shows another form of holder for the said device.
Figure 4 shows the plug of another form of electrical connecting device con-
structed according to my invention.
Figure 5 shows a base plate which takes the place of a socket and serves to
receive the said plug.
Referring more particularly to Figure 1 and 2, a is the body of the plug, b is
the socket which is movably connected to a stem or base b', a spring 2 being inter-
posed between these two parts. cc are the pins on the plug which engage the socket,
and dd are the slots in which the said pins engage, these slots having helical
surfaces e which twist or wind partially round the surface of the sockets after
the manner of screw threads, but which at their inner ends change their direction
and terminate in oppositely inclined portions f.
The socket bis capable of movement endwise or in the direction of its axis,
but cannot turn around such axis. It is therefore drawn toward the plug a
upon the insertion of the latter in the direction of the arrow by the action of
the pins c upon the helical surfaces e, while the contacts or terminals a* of the
plug bear against the corresponding contacts 6* of the socket.
99 are arms extending longitudinally from the wall of the socket 6. These arms
are bent inward at g and engage under the spiral spring 62 which opposes any
upward movement of the cylinder relatively to the stem and to the contacts 6*
and so provides the necessary pressure to ensure proper electrical connection of
the contacts a* and b*.
The construction of holder shown in Figure 3 is substantially similar to that
shown in Figure 2, with the exception that the said holder is provided with a base
plate 6 instead of with a stem, and that the arms are secured to the base plate
instead of to the socket and therefore project in the opposite direction to those
shown in Figure 2. The socket 6 is moreover provided with a cross bar to take
the thrust of the spring 62 this cross bar having recessed extremities embracing
the arms g.
Instead of the plug and holder having each only two contacts, three such
contacts may be provided, the device being thereby adapted for use with a poly-
phase current circuit for example.
With the same object the device may likewise be used with two contacts as
shown and the third conductor of the polyphase circuit connected to, the socket b,
in which case the third terminal of the circuit should also be connected with the
pins c. In this case therefore the two helical surfaces e f act together as current-
conveying contacts for the pins c c.
If however the two helical surfaces are electrically insulated from each other,
acting each as an electric contact for each of the two pins cc, then we have on the
holder and on the plug cach four contacts. Such a form of connecting device
applied to a double pole safety fuze is shown in Figures 4 and 5, the helical
surfaces ef being formed upon separate spring pieces 62, secured upon a base b¹
of insulating material, the elasticity of which spring pieces serving in lieu of
the extra spring as shown in the Figures 2 and 3, to hold the plug a by means
of the pins
cc down in the contacts * of the holder. With the two contacts b*
and the spring pieces there are thus four terminals with which electrical con-
nection may be made. The contacts a* on the plug a are electrically connected
with the pins c as shown by fusible wires c, so that when the plug is secured to
the base plate, the current can pass from the springs 62 to the terminals 6 through
the said fusible wires in the plug. A connecting device of this construction thus
answers very advantageously for a double pole safety fuse.
Obviously I may apply to the ordinary types of bayonet lamp holders, the
improved slots d having continuous and oppositely curved surfaces e f. thus.

page_text: enabling the plugs of such lamp holders to be disengaged by a simple turning
movement.
Dated this 20th day of September 1897
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicant.
Improvements in Electric Connecting Devices, Appшcable to Lamp-
holders, Wall Plugs, and the like..
I, CHARLES LUDWIG RUDOLPH ERNEST MENGES, of Villa Mar, Scheveningen, in
the Kingdom of Holland, and late of Balistraat, The Hague, in the Kingdom of
Holland, Electrical Engineer, do hereby declare the nature of this invention and
in what manner the same is to be performed to be particularly described and
ascertained in and by the following statement:-
This invention relates to improvements in electric connecting devices, applicable
to lamp holders, wall plugs and the like, it being a feature of this invention
that the fastening is obtained by screw action, while however the plug of the
ordinary bayonet holder may be employed.
The essential characteristics of this invention are (1) that the holder is provided
with rigid non elastic contact pieces, (2) that the holder is provided with a movable
sleeve having helical surfaces or slots with which the projecting pins on the
plug. engage, so that by turning the plug while its end face bears upon the
contacts in the holder, it screws the sleeve up so as to compress or extend a spring
with which the latter is provided, thus pressing together the contacts for the
transmission of the current.
It is to be remarked that the rigid contacts referred to under (1), are only
possible by using the device with helical surfaces referred to under (2), for with
the usual bayonet slot it would be practically impossible to insert the plug if the
contacts were not elastic.
In order to prevent the plug from turning back again of its own accord, small
recesses are formed at the extremities of the said helical surfaces, which to a
certain extent act as oppositely inclined screw-threads and tend under the action
of the aforesaid spring to cause the plug to screw itself still further in without
however rendering it impossible to unscrew the same by hand
Owing to the fact that in my improved connecting devices the transmission of
the current is effected, not by means of small springs as is the case with the
ordinary bayonet-joint sockets, but by means of substantial rigid contact surfaces or
terminals, the said connection is in this respect well adapted for safety fuses and
for use with large currents while moreover the making of a good contact is not
dependent upon any manipulation in the insertion of the plug and the latter cannot
become loose of itself.
In my improved connecting devices the advantages of the ordinary screw-
connection and of the bayonet-connection between the socket and plug are combined,
whilst the disadvantages of both are obviated. In addition to this, my improved
devices possess the advantage when employed for safety fuses that the insertion of
the wrong plug, that is to say a plug for too high or for too low a strength
of current, can be prevented by providing the sockets with deeper helical surfaces,
or with special slots; the plugs for the different strengths of current having their

page_text: pins so arranged, that they will only engage with the surfaces or slots of the
sockets to which the said plugs properly correspond.
According to the arrangement of the contacts between the socket and plug the
device may serve for various purposes. For instance if the two helical surfaces
are not included in the circuit, the device may be used for incandescent electric
lamps, for single pole safety fuses, for two wire connecting plugs and the like.
Referring to the accompanying drawings,
Figures 1 and 2 show respectively the plug and holder of an electrical connect-
ing device having my invention applied thereto.
Figure 3 shows another form of holder for the said device.
Figure 4 shows the plug of another form of electrical connecting device con-
structed according to my invention.
Figure 5 shows a base plate which takes the place of a socket and serves to
receive the said plug.
Figure 6 shows an arrangement whereby a shade carrier is attached to a lamp
holder.
Figures 7, 8, 9, and 10 illustrate simple switch arrangements applied to lamp
holders made according to this invention.
Referring more particularly to Figures 1 and 2, a is the body of the plug, bis
the socket which is movably connected to a stem or base 6', a spring being inter-
posed between these two parts. cc are the pins on the plug which engage the socket,
and dd are the slots in which the said pins engage, these slots having helical
surfaces e which twist or wind partially round the surface of the sockets after
the manner of screw threads, but which at their inner ends change their direction
and terminate in oppositely inclined portions f
The socket is capable of movement endwise or in the direction of its axis,
but cannot turn around such axis. It is therefore drawn toward the plug a,
upon the insertion of the latter in the direction of the arrow a, by the action of
the pins c upon the helical surfaces e, while the rigid contact or terminals a* of
the plug bear against the corresponding rigid contacts of the socket.
99 are arms extending longitudinally from the wall of the socket b. These arms
are bent inward at g and engage under the spiral spring which opposes any
upward movement of the cylinder relatively to the stem and to the contacts b
and so provides the necessary pressure to ensure proper electrical connection of
the contacts a* and 6*.
The construction of holder shown in Figure 3 is substantially similar to that
shown in Figure 2, with the exception that the said holder is provided with a base
plate 6 instead of with a stem, and that the arms are secured to the base plate
instead of to the socket and therefore project in the opposite direction to those
shown in Figure 2. The socket bis moreover provided with a cross bar 3 to take
the thrust of the spring 62, this cross bar having recessed extremities embracing
the arms g.
Instead of the plug and holder having each only two contacts, three such
contacts may be provided, the device being thereby adapted for use with a poly-
phase current circuit for example.
With the same object the device may likewise be used with two contacts as
shown and the third conductor of the polyphase circuit connected to the socket b,
in which case the third terminal of the circuit should also be connected with the
pins c. In this case therefore the two helical surfaces e f act together as current
conveying contacts for the pins C C.
If however the two helical surfaces are electrically insulated from each other,
acting each as an electric contact for each of the two pins c c, then we have on the
holder and on the plug each four contacts. Such a form of connecting device
applied to a double pole safety fuze is shown in Figures 4 and 5, the helical
surfaces ef being formed upon separate spring pieces 62, secured upon a base b
of insulating material, the elasticity of which spring pieces serving in lieu of
the extra spring b² as shown in the Figures 2 and 3, to hold the plug a by means

page_text: nection
may
of the pins c c down on the contacts 6 of the holder. With the two contacts 6*
and the spring pieces there are thus four terminals with which electrical con-
be made. The contacts a* on the plug a are electrically connected
with the pins c as shown by fusible wires c, so that when the plug is secured to
the base plate, the current can pass from the springs 62 to the terminals b* through
the said fusible wires in the plug. A connecting device of this construction thus
answers very advantageously for a double pole safety fuse.
Obviously I may apply to the ordinary types of bayonet lamp holders the
improved slots d having continuous and oppositely curved surfaces e f, thus
enabling the plugs of such lamp holders to be disengaged by a simple turning
movement.
• In
Referring to Figure 6, showing a shade carrier attached to a lamp holder, the
stem or base 61 has fixed to it the cylinder 64 which is externally screw threaded
to receive the nut 65 which serves to hold the lamp shade, the latter being thus
supported from the base or stem b¹ and in no way interfering with the movement
of the socket 6 or with the action of the spring 62 which holds the lamp in the
holder.
Lamp holders made according to this invention allow the use of very simple
switch arrangements, such as indicated in Figures 7 and 8 or in Figures 9 and 10.
In the arrangement shown in Figures 7 and 8, a piece, S, of insulating material
traverses the socket band terminates outside the latter in a switch handle of
ordinary construction. The holes in the socket b through which passes the piece S,
(which is of course of circular shape at these points), are of a suitable shape and
size to allow the necessary play of the socket for the insertion of the lamp base.
Just above each of the contacts 6, the piece S is provided on opposite sides with
contacts 6, these contacts being connected as shown in Figure 7. It is obvious
that, when the piece S is in the position shown, a lamp inserted in the holder will
be insulated from the contacts 6, while after a quarter turn of the switch electrical
connection will be established by the contacts **.
In the arrangement shown in Figures 9 and 10 a wedge shaped insulating
pieces provided with knobs at both ends is inserted so as to traverse the socket b
between the contacts 6*, which latter, in the position shown, protrude a little above
the said pieces and thus allow electrical connection with the lamp. When this
piece s, however, is pushed in the direction of its own length so as to assume the
position shown in dotted lines, it will lift the lamp out of connection with the
contacts 6*.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is: —
_
1. A holder for bayonet plugs as used for lamp caps, fuse plugs or the like,
fitted with rigid fixed contact pieces, and with helical surfaces or slots movable
in the direction of the axis of the holder but retained by spring action, so that
when the bayonet plug is turned round in the holder while its side pins engage
with the said helical surfaces and while its end contacts bear upon the contact
piece in the holder, then the helical surfaces are pushed back against the spring
action, thereby pressing the contacts together.
2. A double pole safety fuse in the shape of a bayonet-plug fitted in a holder
according to Claim 1, the ends of the fuse wire being respectively connected to
the side pins and to the end contacts of the bayonet plug.
3. In a holder according to Claim 1, a cylinder with screw thread fixed to the
base of the holder and a nut on said screw thread, substantially as described with
reference to Figure 6.
4. A switch arrangement for lamp holders according to Claim 1 consisting in
an insulating piece movable around an axis and fitted with contacts substantially
as described.

page_text: 5. A. switch arrangement for lamp holders according to Claim 1, consisting of
a wedge shaped insulating piece, movable in the direction of its length; by means
of which the lamp may be lifted out of reach of the contacts of the holder.
.”
1.
T
1000
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C.;
Agents for the Applicant.