Improvements in Springs.
Year: 1894

page_text: Date of Application, 28th Mar., 1894-Accepted, 28th Apr., 1894
Improvements in Springs.
A communication from EDUARD FRANKENBERG, of Hanover, in the Empire of
Germany, Manufacturer.
I, Alfred JULIUS BOULT, of 323 High Holborn in the County of Middlesex,
Chartered Patent Agent, 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 :-
In the manufacture of mattresses and upholstery, only the known forms of
coiled and spiral springs have hitherto been used, which in external appearance
are like two truncated cones one inverted and placed on the other; the cylindrical
coiled spring and the single helical spring have also occasionally been used
experimentally.
By the application of plugs and capsules it has been rendered possible also to use
in upholstery any other form of wound-spring, such as those shown in the annexed
drawings Sheets I & II.
Fig. 1 (Sheet I) represents a spring composed of convolutions of different
diameters, so arranged that each convolution forms part of a circle S interrupted
by a closed loop S¹, the circular part and the loop having one common centre.
Fig. 2 (Sheet I) is a plan of the same spring.
Fig. 3 shows a spiral spring whereof the convolutions first describe a circle S
with the centre m, followed by a semicircle S³ with the centre m³ its radius being
only half that of the first circle; from the centre m (where the semicircle ends)
the convolution proceeds to trace a second full circle S with the centre m² and a
radius equal to that of the first circle; and from the point m to which it returns
the second semicircle S5 is completed from the centre m¹ ending at m², whence the
series is repeated in the same order.
Fig. 4 is a plan of the same spiral.
Fig. 5 (Sheet II) shows a further development the arrangement of the circular
convolutions in each, respectively, being clearly shown in Figs. 6 and 8. In
Fig. 5 the wire first describes ths of an outer circle S, then contracts by the
semicircle S and forms a smaller central circle S¹ returning by the convolution S
into the larger circle, which it again follows over 4ths of a circumference, thence
contracting again by the semicircle S8, once more describes a complete smaller
circle S', returning by semicircle S to the larger circle, and so on, ad lib.
The arrangements shown in Figs. 1, 3, and 5, indicate the desire and attempt to
stiffen the spiral spring by the arrangement of a stiff central core formed by the
eccentric or concentric circles. This object is best attained, however, by the spring
represented in Figs. 7 and 8 (Sheet II) in elevation and plan, which really consists
of a larger circle F' and a smaller circle F' concentric therewith, forming two
independent cylindrical springs, united by connecting the outer one F with the
inner one F at the bottom by means of an intermediate convolution or
semicircle S10 passing from the end of F' to the end of the enclosed F².
The two upper ends of the springs can also be united or simply made fast in any
suitable manner to the capsule or cap-piece slipped on the springs.
The spring action of the one spiral is strengthened by that of the other, so that
the conjoint working is the most favourable that can be conceived for certain
purposes, and the plug-connection of the small spiral suffices to secure the large
spiral spring thereto and enables it to work conjointly therewith.

page_text: The combined springs illustrated in Sheet III of the accompanying drawings
are not wound with a single wire, but the inner spiral F is constructed with a
thinner or weaker wire than the outer one F3 by which it is enclosed; the object to
be attained thereby is that the coils of the bearing-spring proper F* should be
somewhat compressed, which gives it greater stability.
For this purpose two plugs are inserted in the spring F3 on the inner and
opposite surfaces of which the spring F is made fast by means of hooks or clamps,
and the respective heights of the two springs are so proportioned that the outer or
bearing-spring proper F is somewhat compressed before the other spring F' can
be secured to the upper plug.
Fig. 9 shows the springs in their natural condition.
Fig. 10 shows the combination made ready for use.
By this arrangement the spring F is stiffened so that the bending of the
convolutions when the spring is in use is limited, and consequently the durability of
the spring is greatly increased. The spring F is thus called into requisition only
upon pressure being applied, its sole object being to keep the spring F in energetic
action.
Having now particularly described and ascertained the nature of this said
invention as communicated to me by my foreign correspondent, and in what manner
the same is to be performed, I declare that what I claim is;
1. The use of coiled springs for upholstery formed of semicircular convolutions
of different diameters.
2. The use of coiled springs whereof the convolutions form circles of different
diameters which are joined together by semicircular convolutions of the coil and
which circles can be arranged concentrically or eccentrically.
3. The use of double coiled springs consisting of cylindrical springs of different
diameters wound with a single wire and one within the other.
4. The use of wound springs with an inner core formed by arrangements of
convolutions of a smaller diameter, for the purpose of stiffening the larger
convolutions or coiled spring proper and to facilitate the securing thereof.
5. The use of two coiled springs one enclosing the other in the larger or outer
of which upper and lower plugs are inserted and to the inner opposite surfaces of
which the inner coiled springs are fastened by means of clamps or equivalent in
such manner that the outer spring is somewhat compressed and stiffened and the
inuer spring is only called into requisition by a pull the outer spring by pressure
substantially as described.
Dated this 28th day of March 1894.
W. P. THOMPSON & BOULT,
Agents for the Applicant.