GB1585001A – Apparatus for tamping or packing the bed of railway tracks
– Google Patents
GB1585001A – Apparatus for tamping or packing the bed of railway tracks
– Google Patents
Apparatus for tamping or packing the bed of railway tracks
Download PDF
Info
Publication number
GB1585001A
GB1585001A
GB6683/78A
GB668378A
GB1585001A
GB 1585001 A
GB1585001 A
GB 1585001A
GB 6683/78 A
GB6683/78 A
GB 6683/78A
GB 668378 A
GB668378 A
GB 668378A
GB 1585001 A
GB1585001 A
GB 1585001A
Authority
GB
United Kingdom
Prior art keywords
tool
packing
arm
tools
support
Prior art date
1977-02-18
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
GB6683/78A
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Matisa Materiel Industriel SA
Original Assignee
Matisa Materiel Industriel SA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
1977-02-18
Filing date
1978-02-20
Publication date
1981-02-18
1978-02-20
Application filed by Matisa Materiel Industriel SA
filed
Critical
Matisa Materiel Industriel SA
1981-02-18
Publication of GB1585001A
publication
Critical
patent/GB1585001A/en
Status
Expired
legal-status
Critical
Current
Links
Espacenet
Global Dossier
Discuss
Classifications
E—FIXED CONSTRUCTIONS
E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
E01B—PERMANENT WAY; PERMANENT-WAY TOOLS; MACHINES FOR MAKING RAILWAYS OF ALL KINDS
E01B27/00—Placing, renewing, working, cleaning, or taking-up the ballast, with or without concurrent work on the track; Devices therefor; Packing sleepers
E01B27/12—Packing sleepers, with or without concurrent work on the track; Compacting track-carrying ballast
E01B27/13—Packing sleepers, with or without concurrent work on the track
E01B27/16—Sleeper-tamping machines
Description
PATENT SPECIFICATION
2 3 001 re, ( 11) 1 585 001 Application No 6683/78 ( 22) Filed 20 Feb 1978 ‘( 19) ( 31) Convention Application No 2027/77 ( 32) Filed 18 Feb 1977 in ( 33) Switzerland (CH) ( 44) Complete Specification Published 18 Feb 1981 ( 51) INT CL 3 EO 1 B 27/16 ( 52) Index at Acceptance E 1 G 444 GC ( 54) APPARATUS FOR TAMPING OR PACKING THE BED OF RAILWAY TRACKS ( 71) We, MATISA MATERIEL INDUSTRIEL S A, a company organized and existing under the laws of Switzerland, of 2, Arc-En-Ciel, 1023 Crissier, Lausane, Switzerland, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:
The present invention relates to apparatus for tamping or packing the bed of railway tracks of the type comprising a mobile chassis or frame having wheels for rolling on the track rails, at least one support for packing, or tamping, tools vertically displaceable with respect to the frame, at least two packing tools oppositely mounted on the said tool support and each constituted by an arm having at least one pick extending therefrom and provided with an end plate or blade, at least one rotary eccentric or crank-shaft to be driven by a motor journalled in a bearing rigidly connected to the tool support and comprising eccentric bearings on each of which the arm of a packing tool is pivoted by its end remote from the pick so as to impart vibratory oscillations to the said tool, and extensible connection means connecting said arm with the tool support and adapted to effect pivoting of the arm about its pivot.
Similar packing apparatus are known in which the two packing tools, which are substantially rectilinear in configuration and disposed vertically, are pivoted about a rotary crank-shaft to draw one and the other together in the ballast with their pick blades on both sides of a sleeper, or tie, by means of jacks disposed in a generally horizontal position and pivoted at their ends on the one hand to the tool support and on the other hand to the tools at a point on their arms situated generally at the mid-point between their pivot on the crank-shaft and the blade of their pick.
Such packing apparatus are robust and economic by their simplicity of construction but the vibratory oscillations transmitted to the pick stops of the tools similarly pivotally mounted on their pivot points with a horizontal jack connected to the tool support, have a somewhat circular trajectory, the radius of which is proportional to the eccentricity of the off-center bearings of the rotatable shaft.
This circular trajectory of the vibratory oscillations of the pick blades is not desirable, it having been found that the best ballast compacting results are obtained with vibratory oscillations having generally horizontal trajectories or having at the most a very flattened curvilinear form the major axis of which is tangential to the pivotal trajectory of the blade about the crank-shaft on which the tool which carries it is pivoted.
This is why this kind of direction connection of the packing tools with rotary crank shaft turning in a bearing’ rigidly connected to the tool support has been generally replaced, despite its advantages of simplicity, of robustness and of economy, by more complex packing devices.
There is cited by way of example and without dwelling thereon, as such are not the type to which this invention relates, but rather for interest to explain the ballast compacting effect obtained by the horizontal vibratory oscillations of the packing blades, in the best known packing apparatus the desired effect is obtained in practice, in a relatively complex manner by vertical immobilization of the pivot point of the tools and inter-position of a connecting rod between rod between the crank-shaft and the upper ends of the tools.
Similarly there are mentioned packing apparatus which have been proposed to obtain this same desired horizontal displacement effect without the inter-position of connecting rods between the tools and the ( 21) 00 tn r U 1 2 1 585 001 2 crank-shaft but such have never passed the prototype stage due to their complexity.
Likewise there have been proposed packing apparatus in which each tool and rotatable crank-shaft which transmits vibratory oscillations thereto together form a mechanical unit pivoting around a pivotal axis situated between its two ends and integral with the tool support; the upper end of the said tool being connected to the tool support by a jack adapted to provoke its pivoting around the said axis In these packing apparatus each tool comprises a gear box pivotable on the pivotal axis integral with the tool support and comprising an upward extension provided for its connection with the jack and in which is housed the crankshaft, similarly, a fork has a vertically sliding bearing housed between the prongs of the fork and pivoted on the off-center part of the crank-shaft; this fork being angularly connected by rigid attachment to another rotary shaft carried by the said gear box to which is rigidly connected, on the outside, the lower part of the packing tool This construction in which only the horizontal vibratory oscillations are transmitted by the rotatable crank-shaft to the fork integral with the lower part of the tool carrying the packing blade is, it goes without saying, relatively complex and fragile due to the fact of the numerous parts functionally integral one with the other constituting each packing tool.
It has also been proposed, but to another end, to actuate the jack to provoke the pivoting of the packing tools to the point where the member which establishes the connection between the said tools and the crank-shaft is pivoted to the said tools or operates on these In such packing apparatus the crank-shaft no longer turns in a bearing rigidly fixed on the tool support but is rather suspended on the rod of a jack adapted to pivot the tools and connected to the said tool support either by pivoting or by rigid attachment In the first case the tools are elbowed and themselves suspended by their elbows from the tool support by the intermediary of a resilient connection in the horizontal direction In the second case the tools are similarly elbowed but each conforms in two telescopic parts one of which is connected to the crank-shaft and the other is pivoted by its elbow to a pivot integral with the tool support These two proposals result in a movement, not explicitly sought wherein the stops of the packing tools effect generally horizontal vibratory oscillations.
The suspension of the vibrator comprises a bearing and a crank-shaft and its motor at the end of the rod of the jack is delicate and fragile, and the necessity of permitting the free pivotal play of the tools in making these extensible by a telescopic system or, alternatively, in connecting them to the tool support by elastic suspensions is complex, is not rational and again increases the fragility of this system of connection between the packing tools and the tool support.
Examples of patents illustrating prior development are:
Japanese Patent No 35-12706 of May 1958:
U.S A Patents No 3,016,023 of January 9, 1962; No 3,669,025 of June 13, 1972; No.
3,998,165 of December 21, 1976; and Austrian Patent No 206,915 of May 28, 1958.
It is an object of the present invention to provide with simple packing apparatus of the type cited at the beginning of this specification in which the packing tools are directly connected to a rotary eccentric or crank-shaft turning in a bearing rigidly fixed to a tool support, substantially horizontal vibratory oscillations.
According to the present invention there is provided apparatus for compacting the bed of a railway track which apparatus includes a mobile frame for movement along the track, at least one support for tamping tools mounted for vertical displacement on the frame, at least two tamping tools oppositely mounted on said tool support and each comprising an arm having at least one pick extending therefrom and provided with an end blade disposed substantially in a vertical plane, at least one motor driven rotary eccentric shaft, journalled in a bearing rigidly connected to the tool support and comprising eccentric bearings on each of which the arm of a tamping tool is pivoted by its end distal from the pick to impart vibratory oscillations to said tool, the arms of each tool having a generally squared elbowed configuration and a double-acting piston cylinder extending in a substantially vertical direction and pivoted at one end in the region of the elbow of the arm of the tool at a point above the eccentric shaft and at its other end to the tool support to effect pivotal movements of the arm about the bearing whereby to transmit only generally horizontal vibratory oscillations to the tool blades.
The following is a description by way of example of one embodiment of the present invention, reference being had to the accompanying drawings, in which:
Figure 1 is a fragmentary elevation of a portion of a tamping or packing apparatus viewed from the side of the railway track; and Figure 2 is an elevation of the apparatus viewed in the direction of extension of the track from the left-hand side of Figure 1.
A tamping or packing apparatus is shown comprising a mobile chassis or frame 1 of a tamping machine of which only a part thereof is considered necessary to illustrate to provide a proper understanding of the 1 585 001 1 585 001 apparatus The frame 1 is rollingly displaceable along a railroad track of which a rail 2 and a sleeper or tie 3 are shown.
A vertically displaceable packing or tampS ing tool support 4 is suspended from frame 1 and includes two vertical columns 5 and 6 which are rigidly connected to support 4 and vertically slidable in two bearings 7 and 8 rigidly connected to the frame 1.
The raising and lowering of the support 4 is controlled by a hydraulic jack 9 having the end of its piston rod pivotally connected in a bearing 10 integral with a vertical extension 11 of the tool support 4 and the body of which extends across the frame 1 The jack 9 is fixed at its other end to the frame 1 The piston rod and cylinder of the hydraulic jack 9 and the two bearings 7 and 8 are shown fragmented so that such do not extend beyond the frame of the drawing; these members having a length which is sufficient to permit the raising and disengagement of the packing tools above the level of the rail 2.
The packing tool support 4 has a bearing 12 at its lower end, as is clearly shown in Figure 2, which bearing is rigidly connected to support 4 by the intermediary of welded feet 13 and extends transversally above the rail 2.
An eccentric or crank-shaft 14 is rotatable in bearing 12 as seen in section in Figure 1.
The ends of the crank-shaft 14 overhand the bearing 12 and each end comprises two adjacent eccentric bearings on which are pivoted the upper ends of two generally square elbowed arms 15 and 16 for two oppositely mounted packing tools 17 and 18, as well as an inertia fly-wheel 19.
Towards the inside of the track, to the left of Figure 2, the shaft 14 is connected to a hydraulic motor 20 adapted to impart thereto a rapid rotational movement The motor is secured to the tool support 4 by a bracket 21.
The arms 15 and 16 of the packing tools 17 and 18 are extended downwardly by picks 22 and 23 provided with end plates or blades 24 and 25, two picks for each tool arm have been illustrated in the embodiment The two tool arms 15 one on each side of the bearing 12, are here connected by a cross member 26 but this connection is not indispensible This is also true for the arms 16.
The pivoting of the tamping tools 17 and 18 about their pivots on the eccentric bearings of the shaft 14, to bring the blades 24 and 25, spanning the sleeper 5, towards each other in the ballast and move them apart is controlled by double-acting hydraulic jacks 26 and 27 These jacks are extendable in a nearly vertical direction and each connects one packing tool to the support tool 4 in the following manner The body of each of the hydraulic jacks 26 and 27 is pivoted respectively to ears 28 and 29 integral with the arms 15 and 16 of the packing tools 17 and 18 Each of said ear is in the form of a clevis situated in the region of the elbow of the tools, and the rod of each of these hydraulic jacks is pivoted to the vertical extension 11 of the tool support 4 which is constituted by an assembly of welded plates, as shown in Figure 2, which are in the form of a trapezium the smaller side of which is integral with the middle part of the tool support 4 and the major side of which carries at its ends the pivots to which the rods of the hydraulic jacks 26 and 27 are pivoted.
The arrangement of the jacks 26 and 27 with respect to the tools can obviously be reversed but the arrangement described permits a rapid opening of the tools and the application of effective force for the ballast compaction by drawing together of the blades 24, 25 and likewise, great resistance to impact during the insertion of the tools into the ballast.
T He packing apparatus described and illustrated effectively permits substantially only the transmission of horizontal vibratory oscillations to the pick blades of the packing tools and achieves this in an advantageous manner because of its simplicity and its robustness.
Thus, each packing tool, for example the tool 17, is vibrated by the rotation of the eccentric bearing of the shaft 14 to which it is pivoted At this level, the trajectory of the vibratory oscillations of the arms 15 of this tool is circular At the level of the pivot 28 of the arm with the jack 26, the oscillations transmitted can no longer extend vertically because this pivot is integral with the vertically immobilised jack, but only extend on the art of a large radius circle having for its center the pivot of jack 26 with the tool support 4 and on a very small generally horizontal portion of this arc As the distance between the pivot 28 of this jack on the arm 15 and the stop 24 of this tool 17 is fixed it can be considered that the stop 24 can only oscillate on a trajectory in a generally horizontal portion of an arc of a circle having for its center the said pivot 28.
In reality this trajectory is curvilinear but is very flattened and its major axis is generally tangential to the portion of the arc of the circle due to the fact of the combined displacements of the arm of this tool 17 simultaneously about the eccentric of the shaft 14 to which it is pivoted and on the arc described by its pivot 28 connected to the jack 26.
Depending on their size, it can be advantageous to limit the effects of the vertical vibratory oscillations of the packing tools 17 and 18 locked by the jacks 26 and 27, effects which are transmitted by the intermediary 1 585 001 of the tool support 4 and of its control jack 9 to the frame 1.
To this end, the center of mass of inertia fly-wheel 19 can be displaced with respect to the axis of rotation of crank shaft 14 in the direction of the plane of the bisection of the dihedral formed by the two planes joining the said axis of rotation to the two axes of revolution of the eccentric bearings; the effect of this eccentricity of the mass of the fly-wheel 19 naturally being calculated so as to compensate all or very nearly all the effects of the vertical oscillations transmitted to the frame 1 That is to say the mass of the fly-wheel is positioned so as to offset the unbalanced component created by the rotation of the tool arm ends about the eccentric shaft.
Variations and modifications may be effected to the described embodiment of the packing tool without departing from the scope of the present invention.
Similarly, the number of picks per tool can be varied and be limited to a unit; the groups of two oppositely mounted tools on the tool support could be mounted not on a common crank shaft, as described, but each tool of each group mounted on its own crank shaft.
Finally, the packing apparatus itself may be used conjointly with other railway treatment and maintenance apparatus on the same rolling support frame similarly in conjunction with track measuring or analysing apparatus.
Claims (2)
WHAT WE CLAIM IS:-
1 An apparatus for compacting the bed of a railroad track which apparatus includes a mobile frame for movement along the track, at least one support for tamping tools mounted for vertical displacement on the frame, at least two tamping tools oppositely mounted on said tool support and each comprising an arm having at least one pick extending therefrom and provided with an end blade disposed substantially in a vertical plane, at least one motor driven rotary eccentric shaft, journalled in a bearing rigidly connected to the tool support and comprising eccentric bearings on each of which the arm of a tamping tool is pivoted by its end distal from the pick to impart vibratory oscillations to said tool, the arms of each tool having a generally squared elbowed configuration and a double-acting piston cylinder extending in a substantially vertical direction and pivoted at one end in the region of the elbow of the arm of the tool at a point above the eccentric shaft and at its other end to the tool support to effect pivotal movements of the arm about the bearing whereby to transmit only generally horizontal vibratory oscillations to the tool blades.
2 An apparatus for compacting the bed of a railroad track substantially as described with reference to the accompanying drawings.
REDDIE & GROSE, Agents for the Applicants, 16 Theobalds Road, London WC 1 X 8 PL.
Printed for Her Majesty’s Stationery Office, by Croydon Printing Company Limited, Croydon, Surrey, 1981.
Published by The Patent Office, 25 Southampton Buildings, London, WC 2 A l AY, from which copies may be obtained.
GB6683/78A
1977-02-18
1978-02-20
Apparatus for tamping or packing the bed of railway tracks
Expired
GB1585001A
(en)
Applications Claiming Priority (1)
Application Number
Priority Date
Filing Date
Title
CH202777A
CH597429A5
(en)
1977-02-18
1977-02-18
Publications (1)
Publication Number
Publication Date
GB1585001A
true
GB1585001A
(en)
1981-02-18
Family
ID=4224207
Family Applications (1)
Application Number
Title
Priority Date
Filing Date
GB6683/78A
Expired
GB1585001A
(en)
1977-02-18
1978-02-20
Apparatus for tamping or packing the bed of railway tracks
Country Status (15)
Country
Link
US
(1)
US4218978A
(en)
JP
(1)
JPS53124808A
(en)
AR
(1)
AR218476A1
(en)
AT
(1)
AT352169B
(en)
AU
(1)
AU3320878A
(en)
BR
(1)
BR7800980A
(en)
CA
(1)
CA1090657A
(en)
CH
(1)
CH597429A5
(en)
DE
(1)
DE2806898A1
(en)
ES
(1)
ES466999A1
(en)
FR
(1)
FR2381131A1
(en)
GB
(1)
GB1585001A
(en)
IT
(1)
IT7867322D0
(en)
PL
(1)
PL204749A1
(en)
ZA
(1)
ZA78666B
(en)
Cited By (1)
* Cited by examiner, † Cited by third party
Publication number
Priority date
Publication date
Assignee
Title
GB2142069A
(en)
*
1983-06-22
1985-01-09
Dobson Park Ind
Tamping machine
Families Citing this family (9)
* Cited by examiner, † Cited by third party
Publication number
Priority date
Publication date
Assignee
Title
CH630679A5
(en)
*
1979-08-03
1982-06-30
Sig Schweiz Industrieges
BLOCKING DEVICE FOR A TRACKER ON RAILWAYS.
CH650819A5
(en)
*
1980-10-29
1985-08-15
Canron Inc Crissier
TRACKING DEVICE.
US6978718B2
(en)
*
2004-03-04
2005-12-27
Seyrlehner Georg J
Tamping device and method of tamping a railroad track’s ballast
US7124690B1
(en)
*
2004-04-07
2006-10-24
The United States Of America As Represented By The Secretary Of The Army
Smoke producing mortar cartridge
CN103850157B
(en)
*
2012-12-06
2015-10-28
常州市瑞泰工程机械有限公司
Two pillow tamping unit
CN103850158B
(en)
*
2012-12-06
2015-10-28
常州市瑞泰工程机械有限公司
A kind of two pillow tamping unit
AT517357B1
(en)
*
2015-08-21
2017-01-15
Plasser & Theurer Export Von Bahnbaumaschinen Gmbh
tamping
AT517480B1
(en)
*
2015-11-18
2017-02-15
Plasser & Theurer Export Von Bahnbaumaschinen Gmbh
Tamping unit and method for submerging a track
AT520267B1
(en)
*
2017-08-08
2020-02-15
Plasser & Theurer Export Von Bahnbaumaschinen Gmbh
Tamping unit for tamping sleepers on a track
Family Cites Families (7)
* Cited by examiner, † Cited by third party
Publication number
Priority date
Publication date
Assignee
Title
US2096724A
(en)
*
1935-01-22
1937-10-26
Lever Brothers Ltd
Aryl mercury alcoholates of dyes
CH315255A
(en)
*
1954-04-06
1956-08-15
Matisa Materiel Ind Sa
Railroad ballast tamper
US2926617A
(en)
*
1955-05-31
1960-03-01
Kershaw Mfg Company Inc
Ballast tamping apparatus
AT209933B
(en)
*
1958-12-02
1960-07-11
Plasser Bahnbaumasch Franz
Track tamping machine
AT303105B
(en)
*
1969-07-24
1972-11-10
Plasser Bahnbaumasch Franz
Machine that can be moved on a railway track to compact the bedding
US3625156A
(en)
*
1969-09-05
1971-12-07
Jackson Vibrators
Ballast tamping workhead
US3714901A
(en)
*
1970-10-12
1973-02-06
Canron Inc
Tie tamper
1977
1977-02-18
CH
CH202777A
patent/CH597429A5/xx
not_active
IP Right Cessation
1978
1978-01-30
US
US05/873,532
patent/US4218978A/en
not_active
Expired – Lifetime
1978-02-03
ZA
ZA00780666A
patent/ZA78666B/en
unknown
1978-02-10
AU
AU33208/78A
patent/AU3320878A/en
active
Pending
1978-02-10
CA
CA296,652A
patent/CA1090657A/en
not_active
Expired
1978-02-15
ES
ES466999A
patent/ES466999A1/en
not_active
Expired
1978-02-15
AT
AT109778A
patent/AT352169B/en
not_active
IP Right Cessation
1978-02-16
IT
IT7867322A
patent/IT7867322D0/en
unknown
1978-02-17
BR
BR7800980A
patent/BR7800980A/en
unknown
1978-02-17
JP
JP1753178A
patent/JPS53124808A/en
active
Pending
1978-02-17
AR
AR271136A
patent/AR218476A1/en
active
1978-02-17
DE
DE19782806898
patent/DE2806898A1/en
not_active
Withdrawn
1978-02-18
PL
PL20474978A
patent/PL204749A1/en
unknown
1978-02-20
FR
FR7804741A
patent/FR2381131A1/en
active
Pending
1978-02-20
GB
GB6683/78A
patent/GB1585001A/en
not_active
Expired
Cited By (1)
* Cited by examiner, † Cited by third party
Publication number
Priority date
Publication date
Assignee
Title
GB2142069A
(en)
*
1983-06-22
1985-01-09
Dobson Park Ind
Tamping machine
Also Published As
Publication number
Publication date
PL204749A1
(en)
1978-11-20
BR7800980A
(en)
1978-09-19
CH597429A5
(en)
1978-04-14
AT352169B
(en)
1979-09-10
AU3320878A
(en)
1979-08-16
ATA109778A
(en)
1979-02-15
CA1090657A
(en)
1980-12-02
FR2381131A1
(en)
1978-09-15
DE2806898A1
(en)
1978-08-24
ES466999A1
(en)
1978-10-16
ZA78666B
(en)
1978-12-27
JPS53124808A
(en)
1978-10-31
US4218978A
(en)
1980-08-26
IT7867322D0
(en)
1978-02-16
AR218476A1
(en)
1980-06-13
Similar Documents
Publication
Publication Date
Title
US4218978A
(en)
1980-08-26
Apparatus for tamping or packing the bed of railway tracks
CN1092834A
(en)
1994-09-28
The machinery that is used for the railway roadbed of tamping track
JPS5814521B2
(en)
1983-03-19
Kidōtsukigatamekikaiyounotsukigatamekogu unit
CA1088375A
(en)
1980-10-28
High speed production tamper compactor
CA2040895C
(en)
2000-06-27
Ballast tamping assembly
US3753621A
(en)
1973-08-21
Concrete-working machine with walking vibrators
CA1180948A
(en)
1985-01-15
Ballast tamping tool unit
CA1180597A
(en)
1985-01-08
Tamping tool assembly
US3120194A
(en)
1964-02-04
Ballast tamping machine
EA039948B1
(en)
2022-03-31
Tamping assembly for tamping sleepers of a track
US4096806A
(en)
1978-06-27
Track tamper with hingeable unitary pivotable tamping unit
CA1282282C
(en)
1991-04-02
Railway track tamping machine
CN212859817U
(en)
2021-04-02
Assembled building model platform vibrator
SU1026658A3
(en)
1983-06-30
Track-packing machine
JPS57133903A
(en)
1982-08-18
Track floor press solidifying apparatus of railroad track
US3012516A
(en)
1961-12-12
Light tamping machine
RU2216624C2
(en)
2003-11-20
Track machine tie-tamping set
CN214459251U
(en)
2021-10-22
Portable railway track bed ramming machine
US3429277A
(en)
1969-02-25
Ballast tamping assembly
SU1405993A1
(en)
1988-06-30
Arrangement for compacting concrete mix
JPH0738321Y2
(en)
1995-08-30
Roadbed ballast compaction device
RU2098539C1
(en)
1997-12-10
Track liner
SU1532635A1
(en)
1989-12-30
Sleeper-tamping unit
RU2193615C2
(en)
2002-11-27
Ballast tamper
SU988949A1
(en)
1983-01-15
Apparatus for compacting ballast under rail track sleepers
Legal Events
Date
Code
Title
Description
1981-11-04
CSNS
Application of which complete specification have been accepted and published, but patent is not sealed