A Collapsible Centre for Supporting Arches.
Year: 1898

page_text: Date of Application, 21st Mar., 1898
Complete Specification Left, 7th Dec., 1898-Accepted, 18th Mar., 1899
PROVISIONAL SPECIFICATION.
A Collapsible Centre for Supporting Arches.
1, Hugh JorweRTH ROBERTS, M.I.Mech. E., of Messrs. Burn & Company, En-
gineers, Howrah, residing at No. 33, Telkul Ghat Road, Howrah, in the Presidency
of Bengal, British India, do hereby declare the nature of this invention
to be as follows:
-
My invention relates to a centre to support the crown of a sewer or arch
during construction, which centre can be easily withdrawn after the arch has been
constructed by turning a screw which causes the centre to get smaller in
diameter so that it can run freely in the culvert.
It consists chiefly of a centre shaft having right and left hand screws. On this
shaft are fitted nuts to which are attached arms the other ends of which arms
carry a hinged frame to support the arch during the operation of building. On
the screw being turned in one direction these arms straighten out at right
angles to the shaft and force out the frame in position to support the arch which
is then built on the top of the frame. When the arch has been completed the
screw is turned in the opposite direction whereupon the arms are forced towards
the centre shaft and the frame contracts allowing the wheels of a trolly carrying
the whole centre to rest on the floor of the culvert. The centre can then be
run out from under the constructed arch and be placed in position for making
another section of the arch.
01
1
1000
CARPMAEL & Co.,
Agents for the Applicant.
A Collapsible Centre for Supporting Arches.
I, HUGH JORWERTH ROBERTS, M.I.Mech.E., of Messrs. Burn & Company, En-
gineers, Howrah, residing at No. 33, Telkul Ghat Road, Howrah, in the Presidency
of Bengal, British India, 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:-
66
My invention relates to a centre to support the crown of a sewer or arch
during construction which can be easily withdrawn after the arch has been
constructed by turning a screw which causes the
centre" to get smaller in
diameter so that it can run freely in the culvert.
Figure 1 of the accompanying drawings is a longitudinal vertical section,

page_text: Figure 2 is a longitudinal horizontal section and Figure 3 an end view of my
collapsible centre, similar parts being figures alike in all three views.
J is the centre shaft having right and left hand screws cut on it and fitted with
nuts H, to which are attached broad vertical arms F F¹ and light horizontal
arms K.
The outer ends of the vertical arms are attached to channel irons A
and A¹ and those of the horizontal arms to blocks L. Onto the channel iron A
are hinged at C quadrantal plates B stiffened by longitudinal angles E and G
and by ribs D. The lower sides of these plates B are attached to the blocks L
and angle irons G. M is a carriage or trolly with wheels N on which the
whole centre is carried when desired. P is a hand wheel attached to screw J.
Q is a handle attached to the carriage by means of which the centre may be
run in and out of the drain or culvert.
The invert of the sewer or drain having been constructed in the usual manner,
the collapsible centre is run into position on the wheels N. The hand wheel P
is then turned causing the screw J to rotate and the latter having right and
left hand screw threads causes the nuts H to move in towards the centre. This forces
out the channel irons A A' as the arms F gradually come into a vertical position.
The bottom channel iron A¹ rests on the bottom of the drain, the screw J
and carriage M having been lifted by the movement of the nuts towards the
centre. Simultaneously with the movement of the arm F, the horizontal arms K
force out the blocks L together with the plates B. When these plates have
been forced out to their proper position, the crown of the sewer or drain is built
on top of the plates B which support the arch until it is completed.
The top
When the crown of the sewer has been built up, the hand wheel P is turned
in the opposite direction moving the screw J which forces the nuts outwards in
the opposite direction to that above described and ways from the centre of the
screw, causing the channel iron A¹ to rise. This lowers the screw J and car-
riage M and allows the wheels N to rest on the invert of the sewer.
channel A and side plates B are also drawn in towards the screw.
the outside diameter of the centre and allows it to be run out clear of all brick-
work and into position again for a further length of sewer to be built. Figure 3
shows the centre in position with arms extended and the brick or concrete of the
crown of the sewer in position.
This reduces
I would have it understood that I do not confine myself to the particular
arrangement here described but retain to myself the right of varying the same
so long as I do not depart from the essence of my invention. For instance the
number of arms used for forcing out the plates B may be increased and their
position altered should it be deemed desirable.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to bo performed, I declare that what
I claim is:
1. In centres, the use of a right and left handed screw with nuts and arms, as
described.
2. In centres, the use of a frame hinged together as described.
3. The arrangement and combination of the various parts substantially for 4
the purposes aforesaid.
Dated this 7th day of December 1898.
CARPMAEL & Co.,
Agents for the Applicant.