Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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The present invention relates to improvements in a tamp-
ing head for tamping ballast underneath a track including rails
supported on a plurality of spaced ties resting on the ballast
and defining cribs therebetween.
U. S. patent No. 2,872,878, dated February 10, 1959,
discloses a tamping head with a pair of tamping tools, a
vertically adjustable carrier whereon the tamping tools are
mounted for immersion in the ballast in the cribs adjacent
respective ones of the ties, the ties being positioned between
the tamping tools, each tamping tool being constituted by a
lever pivotal in a substantially vertical plane extending in
the direction of the track about a horizontal pivot extending
substantially transversely to the track direction. The tamp-
ing tools are connected to power drives for reciprocating the
tools in the plane about the pivot and for vibrating the tools,
and stop means limit the reciprocation of the tamping tools
within a range defined by a minimum and a maximum reciproca-
ting stroke. According to the patent, the stop means is ad-
justably arranged to move from an inoperative position per-
mitting a maximum reciprocating stroke into an operative
position limiting the reciprocation to a minimum stroke, the
stop means being operated by hydraulic drives so that successive
single and double ties may be tamped selectively and in a con-
tinuous operation, the reciprocating stroke of the tamping
tools being selected according to the width of the tie to be
tamped. In this manner, double ties mounted under the rail
joints may be tamped without substantial time delay as the
tamping operation proceeds from tie to tie. However, a
single adjustment of the reciprocating stroke to adapt to a
double tie does not make it possible to tamp tracks with
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different tie spacings, such as the large tie spacings
used in branch tracks and smaller tie spacing used on
main lines. Furthermore, considerable difficulties and time
delays have been encountered in tamping tracks whose tie
spacings are irregular or whose tie spacings are regularly
or irregularly reduced towards the rail joints, the
spacing at the joints being no more than one or two tie
widths. These difficulties are further increased with
the type of tamping tool assembly wherein two pair~ of
tools are arranged for tamping two adiacent ties simultan-
eously.
It is the primary object of this invention to provide
a tamping head of the indicated type which overcomes the
described disadvantages and permits substantially con-
tinuous tamping in an operation proceeding from tie to
tie, or groups of simultaneously tamped ties, without
substantial time delays for adjustment to different tie
spacings and/or widths.
The above and other objects are accomplished in accord-
ance with the invention with a stop means arranged to set
at least three different opening widths of pairs of
cooperating tamping tools and including a remote-controlled
multi-step drive for setting the stop means. The stop
means is associated with one of the tamping tools for
positioning the pivot of the one tamping tool in at least
three different fixed positions with respect to the pivot
of the other tamping tool of the pair in the track direction,
and a remote control operates the stop means to move the
stop means into a selected fixed position whereby the
distance between the pivots of the
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tamping tools of the pair is changed without changing
the stroke of the reciprocating power drive means. The
stop means includes a multi-step drive operated by the
remote control for setting the stop means at the selected
position.
The present invention is based on the finding that
a minimum of three settings determining the opening width
of the tamping tools, the settings corresponding to the
average differences in crib and/or tie widths, will make
such an uninterrupted tamping operation possible under
practically all practical track conditions. The remote
control of the stop means drive, particularly from an
, operating station on a mobile track tamper, will enable
- the tamping to proceed about as rapidly as on tracks with
regular tie spacing. In addition, the uniformity of the
distance of the immersed tamping tools from the adjacent '
ties can be assured by the individual setting of each
tool,thus improving the accuracy of the track positioning
obtained by the tamping.
The above and other objects, advantages and features
of this invention all become more apparent from the
following detailed description of certain now preferred
embodiments thereof taken in conjunction with the
accompanying drawing wherein
FIG. 1 is a schematic side view of a mobile track
tamper incorporating one embodiment of a tamping head
according to the invention, including a schematic showing
of different settings for the opening width of the tamping
tools;
FIG. 2 is an enlarged side view of the tamping head
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of FIG. l,partly in section to show a detail of the
stop means drive;
FIG. 3 is a section along line III-III of FIG. 2;
FIG. 4 shows the four-step drive of FIG. 2 on an
enlarged scale; and
EIG. 5 is a schematic side view of another embodiment
of a tamping head according to this invention.
Referring now to the drawing and first to FIG. 1,
a generally conventional mobile tamper is shown to
comprise machine frame 1 mounted on undercarriages for
mobility on track rails 2 supported on a plurality of
spaced ties S resting on ballast (not shown) and defining
cribs therebetween.
In this embodiment, tamping head 3 is of the type
disclosed, for instance, in U.S. patent No. 3,357,366, dated
December 12, 1967, which comprises two pairs of tamping
tools 5, 6 and 7, 8 mounted on vertically adjustable
carrier 4 for immersion in the ballast in the cribs adjacent
respective ones of the ties, the ties being positioned
between the tamping tools. As shown, the pairs of tamping
tools are spaced from each other in the track direction,
the spacing being such that the tools 6 and 7 of each
pair, which are adjacent to each other, are immersible
in the same crib whereby two adjacent ties are respectfully
positioned between the adjacent tools 6, 7 and outer
tools 5, 8 of the pairs.
Each tamping tool is constituted by a lever pivotal
in a substantially vertical plane extending in the direction
of the track about a horizontal pivot 16, 17 and 18, 19
extending substantially transversely to the track direction.
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A power drive mean~ consisting in the illustrated embodiment
of hydraulic motors 13, 13 and 14, 14 reciprocates the
tamping tools in the plane about the pivots, and a power
drive means consisting in the illustrated embodiment of
central crank shaft drive 15 vibrates the tamping tools,
all of the above-described structure being generally con-
ventional and, therefore, being described only in general
outlines. t
According to the invention, stop means is arranged for
setting four different opening widths 0, I, II and III
by means of remote-controlled four-step drive 9 so that
the opening of the tamping tools of each pair i.e. their
widest distance from each other, may be set to four
different widths. Control 10 is mounted in the range of
the operating station on the mobile tamper for inde-
pendently actuating the drive for each tamping tool,
a control circuit including a power source (not shown)
and electrical conductor~ connecting remote control 10
to drives 9. The track tamper also comprises odometer 11
and tie sensor 12.
The tie spacing of the track shown in FIG. 1 is irregular,
the distances between adjacent ties S gradually decreasing
towards the rail joint located in the range of tamping
tool 5. Thus, in addition to the average tie spacing
X3, wider tie ~pacings X4 are noted in the range of the
front undercarriage remote from the rail joint and dec-
reasing smaller tie spacings X2, Xl and X0 are found as
the rail joint is approached and at the joint. The setting
of the tamping tool distances from each other to adjust
to these different spacings will be more fully explained
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in connection with FIG. 4.
As shown in FIGS. 2 and 3, each tamping tool
includes a tool holder and the pivots are positioned
substantially equidistantly from the ends of the tamping
tool holders intermediate thereof. Pivots 17 and 18
for adjacent tamping tools 6 and 7 are mounted on carrier
4 while pivots 16 and 19 for outer tamping tools 5
are linked to one end of two-armed levers 20, 20 mounted
on the tamping tool carrier. As illustrated in FIG. 3,
the tamping tools are arranged for immersion in the
ballast adjacent both sides of each rail 2, each group
of tamping tools adjacent both sides of each rail being
reciprocable about a common pivot, and the one end of
two-armed lever 20 being linked to the common pivots.
~uides 21 extend in the direction of track elongation
and mount each bell crank lever 20 for movement therein
in this direction. mis guide is constituted in the
illustrated embodiment by guide beam 21 on which the bell
crank lever is glidably journaled to constitute the four-
position adjustment for reciprocation of tamping tools
5 and 8.
The illustrated arrangement provides a very simple
and sturdy construction which also is kinematically very
advantageous because the tamping tool pivots are directly
linked to the lever which sets the reciprocating strok~.
With the pivot being centered between the ends of the
tamping tool holders, the tamping tools will remain in
essentially vertical positions in all settings, which
improves the compaction of the ballast and the formation
of a solid ballast bed, and also facilitates the immersion
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of the tamping tools into the ballast.
By moving bell crank levers 20 along guide beam
21 by means of four-step cylinder-and-piston drive 22,
outer tamping tools 5 and 8 of each pair of tools
may be set selectively in positions 0,I,II and III,
as shown in FIG. 2, which settings determine the distance
between the tamping tools and, thus, the width of
the opening between the tools of each pair 5, 6 and
7, 8 in the range between a minimum setting 0, shown
in full lines in connection with tamping tools 5, 6,
and a maximum shown in full lines in connection with ;
tamping tools 7, 8. iThe tamping tools are shown in broken
lines at the end of reciprocation produced by drives
13 and 14.
Drive 22 is shown on an enlarged scale and in detail
in FIG. 4. The illustrated four-step drive comprises
stationary main piston 23 mounted on tamping tool carrier
4, two auxiliary pistons 24, 25 associated therewith and
cylinder 26 common to the pistons and axially movable in ;
relation thereto, the setting lever 20 being coupled to
the cylinder for movement therewith. Cylinder 26 defines
a cylinder chamber into which project annular abutments
26' and 26" for the respective pistons for delimiting the
path of movement of the cylinder relative thereto. Four
hydraulic pressure fluid passages 27', 28', 29' and 30'
in the cylinder connect the cylinder chamber to conduits
27, 28, 29 and 30, respectively, which lead to solenoid
valves 31 and 32 whose inlets are connected to the output
of constant speed pump 37 delivering hydraulic fluid from
sump 38, return lines 39 returning the hydraulic fluid to
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the sump. A control circuit including selector
switch 33 and a power source (not shown) is connected
to the solenoids of the valves which form part of control
10 for drive 22.
The illustrated four-step drive operates in the
following manner,
When selector switch 33 of control 10 is in the
illustrated "O" position, the solenoid of valve 32 is
energized and the valve is in the illustrated operating
position which connects conduit 28 to the hydraulic fluid
supply. In this position, hydraulic fluid is delivered
into the cylinder chamber through inlet 28' to move
cylinder 26 to the left, as seen in FIG. 4, Fhcing tamping
tool 5 into the 0 position which produces the minimum
opening of tamping tool pair 5, 6. This position is useful,
for instance, to permit tamping tool 5 to enter into the
crib at the smallest tie spacing ~0 (see FIG . 1 ) .
When selector swi~ch 33 is moved to the "I" position,
one of the solenoids of valve 31 is also energized to
cause hydraulic fluid to be delivered into conduit 30 whence
it flow~ through inlet 30' to press against auxiliary
piston 24, causing cylinder 26 to be moved to the right
until abutment 26' engages piston 24 to assume position
I shown in chain-dotted lines, valve 32 being actuated to
connect conduit 28 with return line 39 to permit displaced
hydraulic fluid to flow back to the sump. Position I,
as illustrated in FIGS. 1 and 2, is useful in the inter-
mediate X2 tie spacing.
Chain-double dotted tamping tool position II is
obtained by throwing switch 33 into the "II" position
Pi
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in which only the second solenoid of valve 31 is
energized to deliver hydraulic fluid through conduit
27 into inlet 27' against auxiliary piston 25 while
valve 32 is in the rest position connecting conduit
29 to sump 38 to deliver hydraulic fluid through inlet
29' against main piston 23. Under this pressure
against pistons 23 and 25, cylinder 26 will move further
to the right until auxiliary piston 25 engages abutment
26"; displaced fluid flowing out of the cylinder chamber
through conduit 28. mis tamping tool position will be
useful in tie spacings X3.
Where the tie spacing is widest, at X4, selector
switch 33 will be rotated into position "III". In this
position, all the solenoids are de-energized, valves 31 and
32 are in their rest positions, and hydraulic fluid is : ~.
delivered from sump 38 through conduit 29 against main
piston 23 to press cylinder 26 all the way to the right
into position III where piston 23 engages abutment 26". ~ ,
As FIG. 1 shows, three different tie spacings are
usually encountered in tracks between their respective rail
joints, w-ith a fourth spacing found at the joints where
the spacing is usually very narrow or double ties are
positioned. With the settings provided by the illustrated
four-step drive, the necessary adjustments of the opening
widths of the tamping tools may be readily effected.
me adaptation of tamping heads designed for tamping
two ties simultaneously to varying tie spacings has been
particularly difficult and, as has been described here-
inabove, this problem has been successfully solved by
the four-step drive of this invention, which enables
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the tamping tool pairq to be set to four different
opening widths without significantly encumbering the
structure or operation. The hydraulic cylinder-and-
piston drive is a very compact machanism operating
dependably and taking up a minimum of space. The
control of the drive may be effected from the operator's
cabin of the tamper independently for each tie and rail
to adapt the tamping operation to local irregularities,
the adjustments being made without delay and difficulty.
The multi-step setting of this invention may, of
course, also be used with tamping heads mounting a
single pair of tamping tools, as schematically shown
in FIG. 5. The generally conventional tamping head 34
mounts a pair of tamping tools reciprocated about a
central pivot by hydraulic drives 35, the cylinders
of the drives selectively engaging respective limit
switches 36 during reciprocation to set drive 9 in
respective positions O,I and II. As shown in chain-
double dotted lines, in tamping tool setting II, the opening
width of the tools is sufficiently wide to enable a
double tie to be tamped.
It is within the scope of the present invention to
use a common control 10 for the four tamping tools 5
or 8 (see FIG. 3~ which are arrayed transversely of the
track on both sides of a respective rail 2. If separate
controls are used for the tamping tools on each side of
the rail, their opening widths may be individually and
independently adjusted, which is particu~rly useful with
the two-tie tamping heads of the type shown in FIG. 2.
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