An Improved Centre Rest or Steady Rest for Lathes.
Year: 1895

page_text: Date of Application, 9th July, 1895
Complete Specification Left, 8th Apr., 1896-Accepted, 9th May, 1896
PROVISIONAL SPECIFICATION.
An Improved Centre Rest or Steady Rest for Lathes.
I, GEORGE FREDERICK RABUS of 2nd Street, Cedar Rapids, County Linn, .
Iowa, U.S.A., Patternmaker, do hereby declare the nature of this invention to be
as follows:-
This invention relates to a centre rest or steady rest for supporting in lathes
at some distance between the centres comparatively long and slender pieces of
work, such for instance as shafts or spindles which would otherwise bend down
and wobble. The centre rest comprises a standard which may be moved along
the lathe bed and fixed thereto by a bolt and clamping plate. The upper part
of the standard is in the form of a ring the upper half of which may be opened
and closed down and locked upon the lower half. Guide pieces forming the
rest for the object to be turned are fitted in the ring so as to be slid radially
towards or away from the centre. For this purpose one edge of each radial
guide piece is provided with teeth which are engaged by a pinion, one pinion
for each guide piece. Each pinion is engaged and operated by a toothed
segment and the segments and with them the pinions and radial guide pieces
have motion communicated to them by turning round the annular plate to which
the segments are fitted said plate being provided with teeth on its periphery
for the engagement of a worm operated by means of a crank handle fixed on
the end of the worm spindle. The guide pieces are fixed by set screws after they
have been adjusted.
Dated this 9th day of Jul 1895
THOMAS R. SHILLITO,
89 Chancery Lane, London, W.C., Agent for the Applicant.
I, GEORGE FREDERICK RABUS of 2nd Street, Cedar Rapids, County Linn,
Iowa, U.S.A., Patternmaker, 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 :-
The object of this invention is so to construct a centre rest or steady rest for a
lathe as to provide for a simultaneous and uniform radial movement of the guides.
In the accompanying drawing
I
Fig. 1 is a side elevation of the centre rest of this invention shewn clamped to a

page_text: Fig. 6 shews a modified form of guide adapted to engage with the ring or rack.
shewn in Fig. 5.
Fig. 7 is an elevation on a reduced scale of a ring cap to cover the racks.
A is the standard of the centre rest which is similar to those in general use and
is secured to the lathe bed in any suitable manner. This standard is made divisible,
the upper half of the guide holding ring being hinged to the lower half at C. At
the opposite edge are two lugs D. To fasten the two halves of the ring together
I prefer the device shewn in Fig. 1 which is an excentric hand lever G connecting
with the upper lug by links F and having a bearing on the under side of the lower
lug. a are housings for the guides I, preferably three in number, although two as
indicated by dotted lines in Fig. 1, would to a certain extent, answer the same
purpose. On one side of each guide is a rack i adapted to engage with the teeth
of a pinion L carried in a recess B formed in the standard A. These pinions
extend beyond the guides on one side and engage with the teeth m, n on the
segments M, N, fitted in the annular recess B in one side of the ring. The
segments are connected by a link ○ pivotted at o which imparts simultaneous
movement to both segments M, N, and permits the upper half of the ring to be
raised for placing work in the centre rest. The segments are held from lateral
displacement and the annular recess B is closed against dirt by a pair of semi-
circular plates P, P¹ (Fig. 7), slots p in the same allowing for the necessary
movement of the pivot studs o, the link O being outside the plates (Fig. 4).
studs on which the pinions turn may extend nearly through the holes p' in said
plates and by means of screws c (Fig. 2) and washers d the plates are drawn tightly
against the shoulders B in the side of the ring. As an additional fastening for the
plates screws may be provided, a portion of the screw head overlapping the edge
of each plate. Motion is transmitted to the: segments and thence to the pinions
and guides by a worm H engaging with a rack m¹. The worm is mounted on a
shaft K having a bearing in the standard A and provided with a crank handle J.
It will be observed that the two racks m are external while the rack n is internal.
It is of course practicable to have all. the racks engaging with the pinions external
or all internal. Where both external and internal racks are used as I prefer and
as is shewn in Fig. 1 it is important that the pitch line of all should exactly
coincide so that perfect accuracy of movement may be imparted to the guides.
The
For the purpose of affording additional external bearing to one of the segments M
one end M of the same may be extended into the upper half of the ring. It is
curved back however so as not to interfere with the movement of this portion of
the ring when raised.
In Fig. 5 is shewn a scroll rack n' on a segment N' and in Fig. 6 a corresponding
rack on the guide I'. This construction would, within certain limits of move-
ment, serve in place of the racks and pinions above described and which are greatly
preferred since they largely increase the capacity of the rest.
Provision is made for fastening the guides tightly in any desired position by
means of set screws e should this in any case be necessary.
The centre rest should not only be accurate in itself but should be accurately
. fitted to the lathe. It is therefore desirable to set it in position on the lathe bed
and to ream or grind out the gripping ends of the guides in the lathe itself after
the guides have been set in a suitable position.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
1. In a centre rest for lathes, the combination of a standard having a divided
guide ring, toothed guides mounted therein, segments engaging directly therewith,
and connected by a pivotted connection, and means for rotating said connected
segments whereby concurrent radial movement is imparted to the guides, substantially
as described and shewn.
2. In a centre rest for lathes, the combination of a standard having a divided

page_text: guide ring, toothed guides mounted radially therein, pinions engaging with said
guides, segmental racks mounted in said guide ring adjacent to the guides, and
engaging said pinions, a link connecting said racks, a worm engaging teeth formed
on one of said segmental racks, and a crank shaft for said worm, substantially as
described and shewn.
3. In a centre rest for lathes, the combination of a standard having a divided
guide ring toothed guides mounted radially therein, pinions engaging each guide, a
pair of segmental racks connected by a link and adapted to turn a limited distance
in an annular recess formed in said guide ring, external gear teeth on
one of said
racks engaging one pinion, an external and an internal set of gear teeth on the
other rack, engaging two other pinions, respectively and a worm engaging with a
worm gear on one of the racks, whereby concurrent radial movement is imparted to
the guides, substantially as described and shewn.
4. In a centre rest for lathes, the combination of the divided guide ring A A',
having an annular recess B, the guides I mounted radially therein adjacent to said
recess, the segments M and N provided with racks, m n, the pinions L engaging.
said racks and also said guides, the link O connecting said segments, the semicircular
plates P, P, the worm H engaging the worm gear m', and a crank shaft connected.
to said worm, substantially as described and shewn.
Dated this 8th day of April 1896.
THOMAS R. SHILLITO,
89 Chancery Lane, London, W.C., Agent for the Applicant.