Improvements in Supporting Blocks for use with Machine Tools.
Year: 1893

page_text: Date of Application, 6th Jan., 1893
Complete Sp.cification Left, 3rd Oct., 1893-Accepted, 4th Nov., 1893
PROVISIONAL SPECIFICATION.
[Communicated from abroad by LA SOCIÉTÉ ALSACIENNE DE CONSTRUCTIONS
MÉCANIQUES, of 58bs, Rue de la Chaussée d'Antin, Paris, France.]
Improvements in Supporting Blocks for use with Machine Tools.
I, ERNEST DE PASS, of 78, Fleet Street, in the City of London, Fellow of the
Chartered Institute of Patent Agents, do hereby declare the nature of this inven-
tion to be as follows:-
This invention relates to improvements in that class of supporting blocks
generally used in engineering shops for securing the work on the tables or plates of.
machine-tools.
Heretofore solid wrought or cast-iron liners have been employed for supporting
the work, the height to be attained being completed with small iron wedges or
plates of copper. This mode of supporting is very unsatisfactory, while the strong
pressure of the clamping dogs which secure the work to the table, causes these
small wedges (on which the clamping dog bears merely by its edge) to give way,
so that the finished and unclamped work has a curved or twisted face instead of a
straight or true one.
I
1
This inconvenience is now obviated by employing, for the same purposes, the
herein described expanding block which consists of two metallic hollow wedges or
inclines, superposed, and accurately fitted for sliding freely on each other. The
lower wedge is provided with a longitudinal rib which is dovetailed or T-shaped, in
cross section, and which acts as a guide-way for the upper or sliding wedge by
engaging with a correspondingly shaped groove in the latter. The said rib is
formed with an opening in which loosely works a counterbalanced pawl or catch
swinging loosely on, or together with, a removeable spindle. The nose of this pawl
or catch projects above the upper face of the rib so as to engage with a rack in the
upper wedge, the lower end of said rack being bent upwardly and serving as a nut
for an adjusting screw. This adjusting screw passes through and turns freely in
the end of the upper wedge, but is prevented from longitudinal movement by means
of a'shoulder and collar fixed on the spindle of said screw.
When the expanding-block is to be used, the upper wedge is caused to slide upon
the lower one until it has been brought into contact with the underside of the.work,
the nose of the pawl or catch during this movement passing freely over the teeth
of the rack. Then, by turning the adjusting screw, in the proper direction, the rack
is drawn backwards until that tooth which was nearest to the nose of the pawl is
brought to rest upon it and the upper wedge thus prevented from sliding
downwards. The expanded block will then act exactly like a solid block of the
same height.
'Dated this 6th day of Tenuary 1803
1 '
COMPLETE SPECIFICATION.
Improvements in Supporting Blocks for use with Machine Tools.
I, ERNEST DE PASS, of 78, Fleet Street, in the City of London, Fellow of the
Chartered Institute of Patent Agents, do hereby declare the nature of this inven-
tion and in what manner the same is to be performed, to be particularly described
and ascertained in and by the following statement, reference being had to the
'
.

page_text: accompanying drawings and to the letters and figures marked thereon, that is
to say :-
This invention relates to improvements in, that class of supporting blocks
generally used in engineering shops for securing the work on the tables or plates of
machine tools.
Heretofore solid wrought or cast iron liners have been employed for supporting
the work, the height to be attained being completed with small. iron wedges or
plates of copper. This mode of supporting is very unsatisfactory, while the strong
pressure of the clamping dogs which secure the work to the table, causes. these
small wedges (on which the clamping dog bears merely by its edge) to collapse or
give way, so that the finished and unclamped work has a curved or twisted face
instead of a straight or true one.
This inconvenience is now obviated by employing for the same purposes the
expanding block hereinafter described, and forming the subject of the present
invention.
In the annexed drawings
Fig. 1 is a longitudinal axial section of an expansible supporting block con-
structed in accordance with the invention.
Fig. 2 a transverse section of the same on the line A, B, of Fig. 1, and
Fig. 3 an external view of the rear side of the block, showing the measuring or
recording graduation.
[
This expansible supporting block consists of two metallic hollow. wedges or
inclines 1, 2, superposed and accurately fitted for sliding freely on each other.,: The
lever wedge 1 is provided with a longitudinally extending rib 3 of dovetail, or
Tshape in cross section, and which acts as a guide-way for the upper or sliding
wedge 2, by engaging with a correspondingly shaped groove in the latter. The
said rib is formed with a rectangular opening 4 between the inner sides of which
loosely works a counterbalanced pawl or ratchet 5 arranged to swing freely on,, or
together with, a removable spindle 6. The nose of this pawl or ratchet 5 projects
above the upper face of the rib 3 so as to engage with a rack 7, the lower end, 8,
of which is bent upwardly and serves as a nut for an adjusting screw 9.
This screw
passes through, and turns freely in, the end of the upper wedge, but is prevented
from longitudinal movement by means of shoulder 10 and collar 11 fixed on the
screw spindle.
The working of this device is as follows:-Supposing that a long and flexible
piece of work, such as a connecting rod for locomotive wheels, is to be secured on
the table of a grinding or milling machine. This connecting rod rests upon its two
heads, but the middle part thereof must be supported at several points, otherwise
it would sink under the pressure of the working tool. In order to avoid this incon-
venience the hereinbefore described expanding block is set under the middle part
of the rod. The upper wedge is pushed upwards and is thus caused to elide upon
the lower one until it has been brought into contact with the underside of the work,
the nose of the pawl or ratchet passing freely, during the movement, over the teeth
of the rack. Then by turning the screw 9 in the proper direction, the rack is
drawn backwards until that tooth thereof which was nearest to the nose of the pawl,
is brought to rest upon it, and the upper wedge thus prevented from sliding back-
wards. The expanded block will then act exactly like a solid block of the same
height. The graduation on the lower wedge and index on the upper one enable the
height of the block or relative position of the two wedges to be measured and
recorded with the utmost accuracy.
Having now particularly described and ascertained the nature of this inven
tion, and in what manner the same is to be performed, I claim :-
1. An expanding block consisting of two hollow wedges superposed and connected
together by means of a suitably shaped rib formed in one of the wedges and
engaging a correspondingly shaped groove in the other wedge, a counterbalanced

page_text: and freely swinging pawl or ratchet located in the lower wedge and engaging with
a rack in the upper wedge, and an adjusting screw (preventing from longitudinal
movement by a shoulder and collar fixed thereon) for working and controlling said
rack, substantially as and for the purpose set forth.
2. The improved expansible supporting block for use with machine tools,
substantially as described and shown with reference to the annexed drawings.
Dated this 3rd day of October 1893.
ERNEST DE PASS.