Improvements in Dredgers.
Year: 1898

page_text: Date of Application, 31st Dec., 1898-Accepted, 25th Feb., 1889
COMPLETE SPECIFICATION.
Improvements in Dredgers.
I, FRED LOBNITZ, Director of Lobnitz & Company Limited, residing at
Clarence House, Renfrew, County of Renfrew, Scotland, 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 dredgers and it has for its object to provide an arrange-
ment of buffer springs whereby the length of motion of the bucket ladder of the
dredger, due to shocks, can be adjusted according to requirements
This buffer spring arrangement is of great advantage, on bucket dredgers, when
working in a sea-way or dredging haid materials
An in order that my said invention may be properly understood I have here.
unto appended two explanatory sheets of diawings, whereon,
Fig i is a side elevation and Fig 2 a plan of the buffer spring arrangement.
Fig 3 18 a part section diawn to an enlarged scale and Fig 4 is a plan of Fig 3
Fig 5 is a cross section taken on the line A-B whilst Fig 6 18 à cross section
taken on the line C-D
Refering to the drawings whereon the same reference letters wherever repeated
indicate the saine parts
The suspension shaft b of the ladder a projects, at each side, through slots c
made in the brackets or bearers d, d, of the guides e, f, which latter are secured
upon the usual supporting framing p Holes are made in the ends of the shaft b
and through these holes the upper ends of screwed tension rods g, 9, are passed
being held securely in place by washers h and nuts > Each tension rod has
strung upon it a certain number of springs which number can be regulated
according to the spring tension desued to put upon the ladder
The guides as shown at Figs 5 and 6, are made of metal plates built up in the
form of box girders with open spaces at interval Each spring, at one end, bears
against a washer held in place by the gider guides and, at the other end,
against a washer which can be moved up and down its screwed tension 10d by
means of a nut m The spaces left at intervals in the guides enable the nuts m
to be turned upon the tension iods so as to increase or decrease the tension of
the springs.
The tension rods are supported by and work upon grooved rollers » revolving
on pins o secured in the guides
With this invention, as can be readily seen, a large number of springs can be
strung upon the tension rods and adjusted so as to act together The cumulative
resistance of the springs, after each one has been individually adjusted, carf be
regulated by turning the nuts ?, ?
If desired, in order to increase the travel allowed the suspension shaft 6 and
the ladder a connected to it, the shaft b could be connected to the long arm of a
lever (or more than one lever might be employed) whose short arm has the springs
in tension attached to it. With this arrangement should the leverage be, say,
1 to 4 then if the springs each compressed 9 inches the travelling space allowed
the shaft b would be 4 x 9 or 36 inches

page_text: 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 consider novel and desire to claim is..
1 The application and use in conjunction with the ladder of a dredger of tension
rods provided with a series of buffer springs capable of being adjusted so as to
act together, substantially as and for the purpose set forth
2 The construction of general arrangement and combination of parts of the
buffer spring device, substantially as herein before described with reference to the
diawings annexed
Tinted the 20th day of December 1898
HD FITZPATRICK,
Glasgow and London, Agent