US2714498A - Props or shores - Google Patents

Props or shores Download PDF

Info

Publication number
US2714498A
US2714498A US284190A US28419052A US2714498A US 2714498 A US2714498 A US 2714498A US 284190 A US284190 A US 284190A US 28419052 A US28419052 A US 28419052A US 2714498 A US2714498 A US 2714498A
Authority
US
United States
Prior art keywords
discs
outer tube
bolt
tube
pin
Prior art date
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 - Lifetime
Application number
US284190A
Inventor
Wuthrich Ernst
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.)
FINANC POUR L IND METALLURG S
FINANCIERE POUR L'INDUSTRIE METALLURGIQUE S A Ste
Original Assignee
FINANC POUR L IND METALLURG S
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.)
Filing date
Publication date
Application filed by FINANC POUR L IND METALLURG S filed Critical FINANC POUR L IND METALLURG S
Application granted granted Critical
Publication of US2714498A publication Critical patent/US2714498A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • E—FIXED CONSTRUCTIONS
    • E21—EARTH DRILLING; MINING
    • E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
    • E21D15/00—Props; Chocks, e.g. made of flexible containers filled with backfilling material
    • E21D15/14—Telescopic props
    • E21D15/16—Telescopic props with parts held together by positive means, with or without relative sliding movement when the prop is subject to excessive pressure
    • E21D15/20—Telescopic props with parts held together by positive means, with or without relative sliding movement when the prop is subject to excessive pressure with pawl, pin, cross-piece, or the like engaging with ratchet teeth, notches, holes, or the like, spaced apart at intervals
    • E—FIXED CONSTRUCTIONS
    • E04—BUILDING
    • E04G—SCAFFOLDING; FORMS; SHUTTERING; BUILDING IMPLEMENTS OR AIDS, OR THEIR USE; HANDLING BUILDING MATERIALS ON THE SITE; REPAIRING, BREAKING-UP OR OTHER WORK ON EXISTING BUILDINGS
    • E04G25/00—Shores or struts; Chocks
    • E04G25/04—Shores or struts; Chocks telescopic
    • E04G25/06—Shores or struts; Chocks telescopic with parts held together by positive means
    • E—FIXED CONSTRUCTIONS
    • E04—BUILDING
    • E04G—SCAFFOLDING; FORMS; SHUTTERING; BUILDING IMPLEMENTS OR AIDS, OR THEIR USE; HANDLING BUILDING MATERIALS ON THE SITE; REPAIRING, BREAKING-UP OR OTHER WORK ON EXISTING BUILDINGS
    • E04G25/00—Shores or struts; Chocks
    • E04G25/04—Shores or struts; Chocks telescopic
    • E04G25/06—Shores or struts; Chocks telescopic with parts held together by positive means
    • E04G25/061—Shores or struts; Chocks telescopic with parts held together by positive means by pins
    • E—FIXED CONSTRUCTIONS
    • E04—BUILDING
    • E04G—SCAFFOLDING; FORMS; SHUTTERING; BUILDING IMPLEMENTS OR AIDS, OR THEIR USE; HANDLING BUILDING MATERIALS ON THE SITE; REPAIRING, BREAKING-UP OR OTHER WORK ON EXISTING BUILDINGS
    • E04G25/00—Shores or struts; Chocks
    • E04G25/04—Shores or struts; Chocks telescopic
    • E04G25/06—Shores or struts; Chocks telescopic with parts held together by positive means
    • E04G25/065—Shores or struts; Chocks telescopic with parts held together by positive means by a threaded nut
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T403/00—Joints and connections
    • Y10T403/32—Articulated members
    • Y10T403/32254—Lockable at fixed position
    • Y10T403/32426—Plural distinct positions
    • Y10T403/32442—At least one discrete position
    • Y10T403/32451—Step-by-step adjustment
    • Y10T403/32459—Retainer extends through aligned recesses
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T403/00—Joints and connections
    • Y10T403/70—Interfitted members
    • Y10T403/7075—Interfitted members including discrete retainer
    • Y10T403/7077—Interfitted members including discrete retainer for telescoping members
    • Y10T403/7079—Transverse pin
    • Y10T403/7086—Wedge pin

Definitions

  • the present invention concerns a prop or shore such as used in making ceiling boardings in building.
  • Props and shores having an inner tube or pipe mounted upon a stand plate, and over which fits, in telescopic manner, an outer tube provided with holes for passing through a pin or bolt.
  • kind have the disadvantage that, on tightening up by means of suitable screwing means, many rotations of the outer pipe may have to be effected with the help of the inserted bolt because in an unfavourable case the full distance between two holes in the vertical direction has to be traversed by screwing the bolt carrying the ceiling plate out of the nut.
  • a prop or shore of the kind described is characterised in that the inner tube or pipe at its upper end supports a pile of discs displaceable axially within the outer tube so that the pin when inserted through the next insertion hole above the upper end of the inside tube may be passed between two adjacent discs.
  • the total height of these superimposed discs will correspond approximately to the distance between two vertically separated insertion holes.
  • a sleeve acting as a container for the discs and having two longitudinal slots lying opposite for passing through the pin or bar.
  • Figure 1 shows an axial section of an embodiment.
  • Figures 2 and 3 show in each case an alternative crosssectional form for the discs.
  • Figure 4 is an axial section through a further embodiment of the invention.
  • An inner tube 3 is placed on the ground 1 by means of a stand plate 2. This inner tube is closed off by means of a cover disc 4 at its top end.
  • An outer tube 5 fits in telescopic manner over the top of the inner tube 3, this outer tube being furnished with holes 6 for passing through a bolt or pin 7.
  • the top end of the outer tube 5 is closed by means of a nut part 8, into the central screw-threaded hole of which is screwed a threaded bolt 9.
  • This bolt is provided at its top end with a support plate intended to be locked against a ceiling boarding 11.
  • the supporting plate 10 is provided with a protecting neck or collar 12, the inside diameter of which is dropping out when the Props or shores of this on the cover part of the 2,714,498 Patented Aug.
  • a pile of discs 13 is placed on the covering disc 4 of the inside tube 3, the outer diameter of these discs being somewhat less than the internal diameter of outer tube 5 so that these discs can easily be displaced axially inside tube 5.
  • the discs have individually the shape of a truncated cone and they are placed upon one another in such a manner that their larger round surface always lies at the top. The total height of these discs corresponds approximately to the distance between two vertically separated holes 6.
  • the pin 7 can be inserted into the first pair of holes 6 situated above the disc 4 between two superimposed discs, the upper discs being moved away from the lower ones by the pin owing to their conical shape.
  • the outer tube 5 can, after the insertion of the pin or bolt, drop back at most the amount of the height of one of discs 13, so that afterwards only this small distance has to be traversed by screwing out bolt 9, and hence the support plate 10, before engagement is produced.
  • the end 71 of bolt 7 is tapered in order to facilitate insertion.
  • the discs 13 may also, as indicated in Figures 2 and 3, have the form of a double truncated cone or of a lens, so that they still act even when one of the discs turns over inside the outer tube 5.
  • These discs 13 are preferably ordinary cast or turned members.
  • the disc members 13 are preferably so dimensioned that their height is less than 2 cm.
  • the reference numeral 1 designates the floor upon which is resting a stand plate 2' of inner tube or pipe 3.
  • the top closure member 4' of the inner tube is reinforced and possesses an axial screw-threaded bore.
  • a pin 19' is capable of rotating, said pin belonging to a supporting plate 10' intended to be pressed against a ceiling surface 11'.
  • a screw-threaded bolt 20' is screwed into the bore of the cover of the inside tube, the top plate 21 of the bolt forming the bottom of the cylindrical sleeve 22' and being rigidly connected thereto.
  • Said sleeve which is inserted into the outer tube possesses two oppositely lying slots 23 to allow of the pin or bar 7 being inserted in any position as regards height of sleeve 22.
  • the sleeve forms a closed container for the lens-shaped discs 13 so that they cannot drop out when the whole support is being dismantled.
  • a pressure or compression spring 24 is also inserted into the sleeve bearing on the topmost disc and against the inside part of the sleeve cover part 25. Cover 25' can be screwed out of the sleeve 22' so as to allow the discs 13' and the spring 24' to be inserted. In this way the discs always remain in the position which is shown and cannot get lost.
  • the bar 7 is then passed through a suitable hole 6' and to do this it may be necessary to move the outer tube 5 round a bit before the bar can pass through slots 23 in the sleeve and pass out at the opposite hole 6'.
  • the bolt 7 slips in between two discs 13.
  • bolt 20' is likewise turned on account of the rigid connection between sleeve 22 and said bolt and it is screwed upwards out of the stand pipe cover 4' and it forces through the medium of discs 13 lying under the bar and the bar itself the outer tube 5' upwards, while the support plate 10' remains in position. After sufficiently strong locking the support is in the position of use, as shown, from which it may be removed by turning back outer tube 5 and withdrawing the bar.
  • a prop or shore comprising an inner tube, an outer tube fitting telescopically thereover and provided with vertically spaced holes, screw means for expanding or shortening the length of the prop or shore, a pile of discs having bevelled edges supported on the upper end of the inner tube and individually displaceable in the axial direction inside the outer tube and of total height corresponding approximately to the distance between two adjacent holes of said spaced holes in the outer tube, and a pin adapted to be selectively inserted through one of the holes in the outer member and disc pile, after extending the prop or shore telescopically to a desired separation.
  • each of the discs is formed as a truncated cone the larger circular surface of which lies at the top and corresponds in its diameter to the inside diameter of the outer tube.
  • each of the discs is formed as a symmetrical double truncated cone the largest diameter of which is smaller than the inside diameter of the outer tube.
  • each of the discs is formed as in a lens shape the largest diameter of which is slightly smaller than the inside diameter of the outer tube.

Description

2, 1955 E. WUTHRICH 2,714,498
PROPS OR SHORES V Filed April 24, 1952 United States Patent PROPS 0R SHORES Ernst Wiithrich, Erlenbach, near Zurich, Switzerland, assignor to Societe Financiere pour llndustrie Metallurgique S. A., Geneva, Switzerland The present invention concerns a prop or shore such as used in making ceiling boardings in building.
Props and shores are known having an inner tube or pipe mounted upon a stand plate, and over which fits, in telescopic manner, an outer tube provided with holes for passing through a pin or bolt. kind have the disadvantage that, on tightening up by means of suitable screwing means, many rotations of the outer pipe may have to be effected with the help of the inserted bolt because in an unfavourable case the full distance between two holes in the vertical direction has to be traversed by screwing the bolt carrying the ceiling plate out of the nut.
According to the present invention, a prop or shore of the kind described is characterised in that the inner tube or pipe at its upper end supports a pile of discs displaceable axially within the outer tube so that the pin when inserted through the next insertion hole above the upper end of the inside tube may be passed between two adjacent discs. The total height of these superimposed discs will correspond approximately to the distance between two vertically separated insertion holes. This makes it possible to raise the outer tube to directly below the surface to be supported and thereupon the insertion pin or bolt can be pushed through the first pair of holes lying above the inner tube or pipe between two discs or in an extreme case over the top disc or under the bottom disc and is then at once supported against the top side of the next underlying disc or the cover of the inner tube, so that only a few turns of the outer tube are needed to lock the support.
Further, according to the invention, rigidly connected with the top end of the inner tube is a sleeve acting as a container for the discs and having two longitudinal slots lying opposite for passing through the pin or bar.
By this means the discs lying inside tube are prevented from support is being dismantled.
The invention will be further described with reference to the accompanying drawings which illustrate embodiments of the invention.
Figure 1 shows an axial section of an embodiment.
Figures 2 and 3 show in each case an alternative crosssectional form for the discs.
Figure 4 is an axial section through a further embodiment of the invention.
An inner tube 3 is placed on the ground 1 by means of a stand plate 2. This inner tube is closed off by means of a cover disc 4 at its top end. An outer tube 5 fits in telescopic manner over the top of the inner tube 3, this outer tube being furnished with holes 6 for passing through a bolt or pin 7. The top end of the outer tube 5 is closed by means of a nut part 8, into the central screw-threaded hole of which is screwed a threaded bolt 9. This bolt is provided at its top end with a support plate intended to be locked against a ceiling boarding 11. The supporting plate 10 is provided with a protecting neck or collar 12, the inside diameter of which is dropping out when the Props or shores of this on the cover part of the 2,714,498 Patented Aug. 2, 1955 greater than the external diameter of the outer tube 5 and whose height corresponds approximately to the length of the screw-threaded bolt 9. The function of this protecting collar is to prevent the dirtying of bolt 9 with mortar, dust and the like. A pile of discs 13 is placed on the covering disc 4 of the inside tube 3, the outer diameter of these discs being somewhat less than the internal diameter of outer tube 5 so that these discs can easily be displaced axially inside tube 5. The discs have individually the shape of a truncated cone and they are placed upon one another in such a manner that their larger round surface always lies at the top. The total height of these discs corresponds approximately to the distance between two vertically separated holes 6.
It can easily be seen that, when the outer tube 5 is lifted so high that the supporting plate is applied against the ceiling boarding 11, the pin 7 can be inserted into the first pair of holes 6 situated above the disc 4 between two superimposed discs, the upper discs being moved away from the lower ones by the pin owing to their conical shape. The outer tube 5 can, after the insertion of the pin or bolt, drop back at most the amount of the height of one of discs 13, so that afterwards only this small distance has to be traversed by screwing out bolt 9, and hence the support plate 10, before engagement is produced. The end 71 of bolt 7 is tapered in order to facilitate insertion.
The discs 13 may also, as indicated in Figures 2 and 3, have the form of a double truncated cone or of a lens, so that they still act even when one of the discs turns over inside the outer tube 5.
These discs 13 are preferably ordinary cast or turned members.
In order that the distance through which the threaded bolt 9 has to be screwed out of its nut 8 may remain within reasonable limits, the disc members 13 are preferably so dimensioned that their height is less than 2 cm.
In the example of construction which is shown in Figure 4, the reference numeral 1 designates the floor upon which is resting a stand plate 2' of inner tube or pipe 3. The top closure member 4' of the inner tube is reinforced and possesses an axial screw-threaded bore.
An outer tube or pipe 5' with holes 6 through which a pin or bar 7 may be passed, is pushed over the inner tube 3' in telescopic manner. In the cover 8' of the outer tube a pin 19' is capable of rotating, said pin belonging to a supporting plate 10' intended to be pressed against a ceiling surface 11'.
A screw-threaded bolt 20' is screwed into the bore of the cover of the inside tube, the top plate 21 of the bolt forming the bottom of the cylindrical sleeve 22' and being rigidly connected thereto. Said sleeve which is inserted into the outer tube possesses two oppositely lying slots 23 to allow of the pin or bar 7 being inserted in any position as regards height of sleeve 22. The sleeve forms a closed container for the lens-shaped discs 13 so that they cannot drop out when the whole support is being dismantled. In the example of construction which is shown, a pressure or compression spring 24 is also inserted into the sleeve bearing on the topmost disc and against the inside part of the sleeve cover part 25. Cover 25' can be screwed out of the sleeve 22' so as to allow the discs 13' and the spring 24' to be inserted. In this way the discs always remain in the position which is shown and cannot get lost.
The manner of using the ceiling support shown and described is as follows:
With bar 7 removed the support, that is its stand plate 2, is placed at the required position on the floor 1'. The outer tube 5 is raised up to such an extent that the supporting plate 10 abuts against the ceiling surface 11.
The bar 7 is then passed through a suitable hole 6' and to do this it may be necessary to move the outer tube 5 round a bit before the bar can pass through slots 23 in the sleeve and pass out at the opposite hole 6'. When passing through, the bolt 7 slips in between two discs 13. When the outer tube 5 is turned in relation to the inside tube by means of the bar 7', bolt 20' is likewise turned on account of the rigid connection between sleeve 22 and said bolt and it is screwed upwards out of the stand pipe cover 4' and it forces through the medium of discs 13 lying under the bar and the bar itself the outer tube 5' upwards, while the support plate 10' remains in position. After sufficiently strong locking the support is in the position of use, as shown, from which it may be removed by turning back outer tube 5 and withdrawing the bar.
What is claimed is:
1. A prop or shore comprising an inner tube, an outer tube fitting telescopically thereover and provided with vertically spaced holes, screw means for expanding or shortening the length of the prop or shore, a pile of discs having bevelled edges supported on the upper end of the inner tube and individually displaceable in the axial direction inside the outer tube and of total height corresponding approximately to the distance between two adjacent holes of said spaced holes in the outer tube, and a pin adapted to be selectively inserted through one of the holes in the outer member and disc pile, after extending the prop or shore telescopically to a desired separation.
2. Prop or shore as claimed in claim 1, in which each of the discs is formed as a truncated cone the larger circular surface of which lies at the top and corresponds in its diameter to the inside diameter of the outer tube.
3. Prop or shore as claimed in claim 1, in which each of the discs is formed as a symmetrical double truncated cone the largest diameter of which is smaller than the inside diameter of the outer tube.
4. Prop or shore as claimed in claim 1, in which each of the discs is formed as in a lens shape the largest diameter of which is slightly smaller than the inside diameter of the outer tube.
5. Prop or shore as claimed in claim 1, in which rigidly connected with the top end of the inner tube is a sleeve acting as a container for the discs and having two longitudinal slots lying opposite for passing through the pin or bar, a compression spring being inserted between the topmost disc and the top of the sleeve.
6. Prop or shore as claimed in claim 5, characterised in that a screw-threaded bolt is screwed into an axially extending bore in the top of the inside tube, the head part of said bolt projecting into the outer tube being rigidly connected with the sleeve.
References Cited in the file of this patent V FOREIGN PATENTS 213,317 Great Britain of 1924 703,063 Germany of 1941
US284190A 1951-04-30 1952-04-24 Props or shores Expired - Lifetime US2714498A (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
CH695937X 1951-04-30
CH909627X 1951-04-30
CH2714498X 1951-04-30

Publications (1)

Publication Number Publication Date
US2714498A true US2714498A (en) 1955-08-02

Family

ID=27178546

Family Applications (1)

Application Number Title Priority Date Filing Date
US284190A Expired - Lifetime US2714498A (en) 1951-04-30 1952-04-24 Props or shores

Country Status (3)

Country Link
US (1) US2714498A (en)
GB (1) GB695937A (en)
NL (1) NL80573C (en)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3285656A (en) * 1965-07-26 1966-11-15 System Communica Aktiebolag Height adjusting devices for chairs, tables, and the like
US3503455A (en) * 1967-07-11 1970-03-31 Deere & Co Overload trip device
US4718628A (en) * 1986-03-21 1988-01-12 Michael Vitta Adjustable shore
US4752057A (en) * 1986-04-18 1988-06-21 Hunnebeck Gmbh Steel tube prop with rapid release
US5054730A (en) * 1990-02-12 1991-10-08 Pensoneau Excavating Co., Inc. Pipe strut system and method for using same
WO1996001353A1 (en) * 1994-07-01 1996-01-18 Concept 2000 Pty. Ltd. A prop
US5667189A (en) * 1995-04-13 1997-09-16 Kester; Michael H. Self-supporting flow hood
WO1999002915A1 (en) * 1997-07-11 1999-01-21 Southland Supply Company, Inc. Adjustable leg

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112648332A (en) * 2020-12-03 2021-04-13 北京科技大学 Spherical cell hole ladder-shaped deformation ore pressure controller and method

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB213317A (en) * 1922-12-06 1924-04-03 William Bateman Atkinson Improvements in or relating to building supports
DE703063C (en) * 1939-04-25 1941-02-27 Bergwerksbedarf G M B H Fab F Iron pit stamp

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB213317A (en) * 1922-12-06 1924-04-03 William Bateman Atkinson Improvements in or relating to building supports
DE703063C (en) * 1939-04-25 1941-02-27 Bergwerksbedarf G M B H Fab F Iron pit stamp

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3285656A (en) * 1965-07-26 1966-11-15 System Communica Aktiebolag Height adjusting devices for chairs, tables, and the like
US3503455A (en) * 1967-07-11 1970-03-31 Deere & Co Overload trip device
US4718628A (en) * 1986-03-21 1988-01-12 Michael Vitta Adjustable shore
US4752057A (en) * 1986-04-18 1988-06-21 Hunnebeck Gmbh Steel tube prop with rapid release
US5054730A (en) * 1990-02-12 1991-10-08 Pensoneau Excavating Co., Inc. Pipe strut system and method for using same
WO1996001353A1 (en) * 1994-07-01 1996-01-18 Concept 2000 Pty. Ltd. A prop
GB2304752A (en) * 1994-07-01 1997-03-26 Concept 2000 Pty Ltd A prop
GB2304752B (en) * 1994-07-01 1998-08-05 Concept 2000 Pty Ltd A prop
US5667189A (en) * 1995-04-13 1997-09-16 Kester; Michael H. Self-supporting flow hood
WO1999002915A1 (en) * 1997-07-11 1999-01-21 Southland Supply Company, Inc. Adjustable leg
US6032914A (en) * 1997-07-11 2000-03-07 Southland Supply Company, Inc. Adjustable leg

Also Published As

Publication number Publication date
GB695937A (en) 1953-08-19
NL80573C (en)

Similar Documents

Publication Publication Date Title
US3858998A (en) Manhole frame
US2714498A (en) Props or shores
US2952947A (en) Anchor bolt assembly
US3655161A (en) Post shore
US2234784A (en) Device for forming passages in concrete
US5310153A (en) Quick release washer for a shoring post
US20050161571A1 (en) Adjustable shoring post
US3042161A (en) Disappearing-type anchor
DE202005003826U1 (en) Height adjustable footrest for bar stool, comprises main shaft, externally threaded conical sleeve and support frame with internally threaded tube
US5564867A (en) Resilienty compressible support column for use in a mine
US4234151A (en) Self-locking adjustable support devices
US4221363A (en) Adjustable jack
CN207079622U (en) A kind of square pattern foundation pit supporting structure barricade supporting construction
US5230199A (en) Splice sleeve for connecting reinforcing bars to another entity
US4074499A (en) Filler plug for coil insert in concrete slab or panel
US2139167A (en) Bolt anchor
US5967702A (en) Quick-release pit prop
US1895053A (en) Prop for mines and means for withdrawing the same
US2776811A (en) Adjustable post
US3469823A (en) Handrail post fitting
DE3208687C2 (en) Auxiliary device for tensioning slips in a wellhead and a correspondingly designed wellhead structure
DE10261338B3 (en) Height-adjustable manhole cover for access shaft for underground gas or water lines has radially projecting raised areas in outside of upper part and inside of lower part of manhole housing providing elastic press-fit
US2148891A (en) Plunger valve
EP3329051B1 (en) Supporting post improvements
CN207714391U (en) A kind of static load test adjustable reference stake