Improvements in Devices for Trueing Up Cylindrical Surfaces, such as Motion Pins and the like.
Year: 1896

page_text: Date of Application, 1st Sept., 18968-Accepted, 31st Oct., 1896
COMPLETE SPECIFICATION.
Improvements in Devices for Trueing Up Cylindrical Surfaces, such
as Motion Pins and the like.
I JOHN DAVIES of 2 Commercial Chambers Manse Street Dunedin in the
Colony of New Zealand Engineer 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 has for its object the trueing up by lapping cylindrical surfaces
and in particular motion pins that are when made or have been worn off the round.
The nature of the invention is as follows;-l take advantage of the natural
spring that is in metal or wood and construct two arms of either material preferably
of cast iron fixed apart at one end and left open at the other end to hold pieces
of copper Babbit's metal or other substance used for like purposes. A circular
clip or screw is attached to the arms at the open eud and by its means the piece
of copper metal or other substance can be brought together or sprung down on
the work to be trued up. The arms (or the work according to circumstances
bereinafter explained) are then revolved and the high places on the work are
worn or rubbed down by the pieces of copper metal or other substance with
preferably emery and oil. The arms having a tendency to spring away from tho
work keep the pieces of copper metal or other substance from touching the low
places on it and consequently it is worn down or lapped dead true round.
In the drawings
Figure 1 is a longitudinal section Figure 2 is an end view and Figure 3 is a
plan of my invention as applied to trueing up crank pins while remaining on the
engine wheels.
Figure 4 shows my invention used as a chuck being screwed on to the lathe spindle
adapted to trueing up or finishing work that is fixed in the lathe and is too large
to revolve.
Figures & 6 show two views of my invention as adapted to trucing up or
finishing work of every description that can revolve in the lathe.
In Figure (A) is a bed plate on which suitable grooves are made for the
flanges of the engine wheels to rest upon. (C) is an adjustable pedestal the bottom
portion of which is securely fitted to the bed (A) by bolts sliding in the slot (B)
in the bed. The upper portion of the pedestal can be raised or lowered in the
block (L) as required to suit the height of different wheels and is fastened in
position by the screw (K). The pedestal also carries the spindle (D) on which the
arms (VV) revolve and projects forward at (T) to carry the forked lever (G)
which pivots at (T) and hinges at (S). The screw (M) is for the purpose of
forcing the conical end of tho spindle (D) into the centre in the crank pin (H)
and consequently pressing the flat side of the wheel (0) against the bearing (P)
in the bed (A). (E) is a casting having arms (V V) which are fitted at the ends
with preferably two copper or Babbit's metal pieces (F F) fastened by screws as
shown more clearly in Figure 2. The grooved pulley (R R) is preferably not
less than four times the diameter of the largest pin to be fapped and may be
driven by rope or catgut. The casting (E) is made preferably of cast iron as
that metal has a certain spring in it which gives a suitable outward tension to the
arms (VV) when tightened together or sprung down to meet ou the crank pin by
means of the clip (H) (see Figures 2 and 3). This olip has a hinge on one side
and a screw on the other as shown. The arms (V V) are semicircular where the

page_text: copper or Babbit's metal pieces are fastened but become flat as they approach the
pulley so as to give the necessary spring to the casting. The cross sections (A'
and B) in Figure 2 show this. The copper or Babbit's metal pieces (FF) are
placed in position before being bored out and the arms (VV) are then sprung
down by the clip (H) about one eighth of an inch. They are then bored out to
the size of the crank pin and the arms will then have the outward tension required.
The copper or Babbit's metal pieces are then removed to allow the arms (VV) to
pass over the collar or flange of the crank pin. They are then replaced and
sprung down upon the crank pin by tightening the clip until they touch the pin.
The pulley (R) is then started to work by suitable motive power and the
arms (VV) revolve carrying the copper or Babbit's metal pieces which wear or
rub with preferably emery and oil the high places on the crank pin and being
moved backwards and forwards by the levor (G) the whole of the working surface
of the crank pin is dealt with. The outward tension of the arms (V V) provents
the rubbing from taking anything off the low placos on the crank pin. The copper
or metal pieces can be tightened as may be from time to time required. In
Figure 4 the lap chuck (EE) is similar in construction to the crauk pin lap
already described but here the device is arranged to screw on the latho spindle as
shown in the drawing. The copper or Babbit's inetal pieces and clip are the
same as in the crank pin lap. Pieces which are too large to revolve in the lathe
to be treated by the hand lap next mentioned can by this method bo lapped
without difficulty. In Figures 5 and 6 a lap is shown suitable for finishing work
of every description which is small enough to revolve in the lathe. The pin
shown at (H) forms a fulcrum and the bolt and thumb screw (J) regulate the
outward tension at the lap end of the tool. The screw at (K) is used for
tightening the lap on the pin. (FF) are the copper or Babbit's metal pieces
screwed into the arms as shown. The arms are sprung down in this tool by a
screw instead of a clip as in the others. Hickory wood may be used instead of
cast iron in this form of my device but I prefer cast iron. I may also use rigid
arms with springs instead of springing arms but I prefer the latter.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed 1 declare that what
I claim is
In a device for trueing up by lapping the exterior of cylindrical surfaces and in
particular motion pins :-
1. The springing arms (V V) constructed arranged and operating as herein-
before described and illustrated.
2. The combination of the springing arms (VV) with the clip or screw. (H')
constructed arranged and operatiug substantially as set forth.
3. The combination and arrangement of parts shown in Figures 2 and 3
constituting the device for trucing up by lapping crank pins constructed and
operating substantially as set forth.
4. The combination and arrangement of parts shown in Figure 4 constituting
the device for trueing up by lapping motion pins when fixed in a lathe substantially
as set forth.
5. The combination and arrangement of parts shown in Figures 5 and 6
constituting the device for trueing up by lapping motion pius when revolved
substantially as set forth.
Dated this 1st day of September 1898.
HASELTINE, LAKE & Co.,
45 Southampton Buildings, London, W.C., Agents for the Applicant.