GB2141204A - Extensible spring strut - Google Patents

Extensible spring strut Download PDF

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Publication number
GB2141204A
GB2141204A GB8313949A GB8313949A GB2141204A GB 2141204 A GB2141204 A GB 2141204A GB 8313949 A GB8313949 A GB 8313949A GB 8313949 A GB8313949 A GB 8313949A GB 2141204 A GB2141204 A GB 2141204A
Authority
GB
United Kingdom
Prior art keywords
tripod
strut
leg
outer tube
legs
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.)
Granted
Application number
GB8313949A
Other versions
GB8313949D0 (en
GB2141204B (en
Inventor
Lionel Vivian Frank Russell
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.)
VINTEN Ltd
W Vinten Ltd
Original Assignee
VINTEN Ltd
W Vinten Ltd
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 VINTEN Ltd, W Vinten Ltd filed Critical VINTEN Ltd
Priority to GB8313949A priority Critical patent/GB2141204B/en
Publication of GB8313949D0 publication Critical patent/GB8313949D0/en
Priority to DE19843417759 priority patent/DE3417759A1/en
Priority to FR8407557A priority patent/FR2546268A1/en
Publication of GB2141204A publication Critical patent/GB2141204A/en
Application granted granted Critical
Publication of GB2141204B publication Critical patent/GB2141204B/en
Expired legal-status Critical Current

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
    • F16F9/00—Springs, vibration-dampers, shock-absorbers, or similarly-constructed movement-dampers using a fluid or the equivalent as damping medium
    • F16F9/02—Springs, vibration-dampers, shock-absorbers, or similarly-constructed movement-dampers using a fluid or the equivalent as damping medium using gas only or vacuum
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
    • F16F1/00—Springs
    • F16F1/36—Springs made of rubber or other material having high internal friction, e.g. thermoplastic elastomers
    • F16F1/42—Springs made of rubber or other material having high internal friction, e.g. thermoplastic elastomers characterised by the mode of stressing
    • F16F1/46—Springs made of rubber or other material having high internal friction, e.g. thermoplastic elastomers characterised by the mode of stressing loaded mainly in tension
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16M—FRAMES, CASINGS OR BEDS OF ENGINES, MACHINES OR APPARATUS, NOT SPECIFIC TO ENGINES, MACHINES OR APPARATUS PROVIDED FOR ELSEWHERE; STANDS; SUPPORTS
    • F16M11/00—Stands or trestles as supports for apparatus or articles placed thereon ; Stands for scientific apparatus such as gravitational force meters
    • F16M11/20—Undercarriages with or without wheels
    • F16M11/24—Undercarriages with or without wheels changeable in height or length of legs, also for transport only, e.g. by means of tubes screwed into each other
    • F16M11/242—Undercarriages with or without wheels changeable in height or length of legs, also for transport only, e.g. by means of tubes screwed into each other by spreading of the legs
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16M—FRAMES, CASINGS OR BEDS OF ENGINES, MACHINES OR APPARATUS, NOT SPECIFIC TO ENGINES, MACHINES OR APPARATUS PROVIDED FOR ELSEWHERE; STANDS; SUPPORTS
    • F16M11/00—Stands or trestles as supports for apparatus or articles placed thereon ; Stands for scientific apparatus such as gravitational force meters
    • F16M11/20—Undercarriages with or without wheels
    • F16M11/24—Undercarriages with or without wheels changeable in height or length of legs, also for transport only, e.g. by means of tubes screwed into each other
    • F16M11/26—Undercarriages with or without wheels changeable in height or length of legs, also for transport only, e.g. by means of tubes screwed into each other by telescoping, with or without folding
    • F16M11/32—Undercarriages for supports with three or more telescoping legs
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16M—FRAMES, CASINGS OR BEDS OF ENGINES, MACHINES OR APPARATUS, NOT SPECIFIC TO ENGINES, MACHINES OR APPARATUS PROVIDED FOR ELSEWHERE; STANDS; SUPPORTS
    • F16M11/00—Stands or trestles as supports for apparatus or articles placed thereon ; Stands for scientific apparatus such as gravitational force meters
    • F16M11/20—Undercarriages with or without wheels
    • F16M11/24—Undercarriages with or without wheels changeable in height or length of legs, also for transport only, e.g. by means of tubes screwed into each other
    • F16M11/26—Undercarriages with or without wheels changeable in height or length of legs, also for transport only, e.g. by means of tubes screwed into each other by telescoping, with or without folding
    • F16M11/32—Undercarriages for supports with three or more telescoping legs
    • F16M11/34—Members limiting spreading of legs, e.g. "umbrella legs"
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
    • F16F2236/00—Mode of stressing of basic spring or damper elements or devices incorporating such elements
    • F16F2236/06—Tension
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16M—FRAMES, CASINGS OR BEDS OF ENGINES, MACHINES OR APPARATUS, NOT SPECIFIC TO ENGINES, MACHINES OR APPARATUS PROVIDED FOR ELSEWHERE; STANDS; SUPPORTS
    • F16M2200/00—Details of stands or supports
    • F16M2200/04—Balancing means
    • F16M2200/044—Balancing means for balancing rotational movement of the undercarriage

Landscapes

  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Health & Medical Sciences (AREA)
  • Child & Adolescent Psychology (AREA)
  • Accessories Of Cameras (AREA)
  • Mutual Connection Of Rods And Tubes (AREA)

Abstract

A strut for fixing between a tripod platform and leg has tension and compression counterbalancing forces, which when combined provide a reaction force approximating the force tending to spread the leg. The strut comprises an inner tube 5 sliding within an outer tube 1. As the strut extends, an elastic cord 11 connected between the tube ends is stretched, and the air in an annular chamber 5 between the tubes is compressed by virtue of seals 4 & 7. <IMAGE>

Description

SPECIFICATION Improvements in or relating to tensioned struts This invention relates to tensioned struts and more particularly, though not exclusively, to tensioned struts for use on such as spreadable tripod legs.
In the field of spreadable legs such as used on tripods etc. one of the main problems encountered is the difficulty of spreading the legs without the tripod and/or legs collapsing. The normal procedure is for each leg to have a locking or clamping device which has to be applied or released for each adjustment of each leg and unless this device is applied correctly to each tripod leg after adjustment the whole tripod is in danger of collapse and damage often occurs to valuable equipment mounted on the tripod. Various types of struts between the legs and tripod platform have been tried such as telescopic struts with clamps, turnbuckles and hinged struts but all these methods are time consuming, frustrating to the user and often nerve racking when expensive machinery is mounted on the tripod.
It is therefore an object of this invention to provide a strut which may be used on such as a tripod which permits angular adjustment of the legs and reduces the possibility of tripod collapse and which would, under the worst conditions, where the load on the tripod is too heavy, sink slowly in a relatively vertical line to the position of all legs fully spread.
According to the invention we provide a strut for a tripod leg or the like comprising, an outer tube having a means for pivotal location on one end, an inner tube of greater length than said outer tube and longitudinally movable therein having a means for pivotal location on its exposed end and a piston at its enclosed end longitudinally slidable within said outer tube, sealing means on said outer tube at its open end in sliding contact with said inner tube and an elastic cord within said inner and outer tubes joining their extremities.
The invention will now be described by way of example, only in conjunction with the accompanying drawings in which: Figure 1 shows the cross section of a strut according to the invention in the closed position.
Figure 2 shows a strut in a part extended and fully extended state and Figure 3 shows a graph of the approximate elastic cord forces, the approximate piston forces and the approximate required force curve.
Referring to Figure 1 a tube (1), to which a vented plug (2) is fitted, has a bracket (3) for pivotal location oftube (1 ) at point A which represents a mounting position for a strut on a tripod platform, not drawn.
Broken line BC represents a tripod leg pivotally located at point B on the tripod platform. A seal (4), such as an '0' ring or a pressed felt pad, is located in a groove in the bore of tube (1) near the open end of tube (1) and is a sliding fit over an inner tube (5) having a shoulder (6) which is a sliding fit in the bore of the outer tube (1). The shoulder (6) forms a piston to which a seal or ring (7) may be fitted so that, on extension of the strut, air in chamber (8) is compressed. Located in the opposite end of inner tube (5) is a vented plug (9) to which a bracket (10) isfitted for pivotally locating the strut, in its relaxed state, to a point D on the tripod leg.A length of elastic cord, also known as shock cord and shock absorber cord, (11) extends internally of the tubes (1 ) and (5) and is attached to the inner tube vented plug at one end and to the outer tube vented plug at the opposite end so that with the strut in the closed position the elastic cord (11) is in a relaxed state.
Referring now to Figures (2) and (3) the tripod legs, only one drawn, are partly spread and the inner tube (5) pivoted at D has been partly withdrawn from the outer tube (1). The elastic cord (11) is now under a degree of tension and the air in chamber (8) is under a degree of compression. The combined effect of the tension and compression forces stop the leg from collapsing to its fully spread state, shown dotted.
The greater the degree of spread of the leg the greater are the tension and compression forces as shown in Figure 3 where curve X represents the approximate reacting force due to compression of the air and curve Y represents, the approximate reacting force due to tension of the elastic cord.
Curve Z represents the approximate required counteracting force and approximates the resultant reacting force, or combination of tension and compression, and the weight on the tripod platform tending to spread the legs is counteracted by the force tending to close the strut and is approximately proportional through the range of spread i.e. the forces acting at P1 balance out and also at P2.
Though extremely stable the strut may be further supplied with a locking means so that during prolonged periods of use in one spread position, the strut would be doubly secure. The locking means may take many forms and a preferred method is the type known as a split block which would clamp over a portion of the exposed inner tube and would normally be fixed to the open end of the outer tube.
Quick action clamping means for such split blocks are well known.
By using this type of strut for tripod legs or the like the possibility of damage to equipment mounted on the tripod platform is greatly reduced and the struts on the tripod legs approximately balance the weight of an article on the tripod platform at any leg spread angle.
1. A strut for a tripod leg or the like comprising, an outer tube having a means for pivotal location on one end, an inner tube of greater length than said outertube and longitudinally movable therein having a means for pivotal location on its exposed end and a piston at its enclosed end longitudinally slidable within said outer tube, sealing Heans on said outer tube at its open end in sliding contact with said inner tube and an elastic cord within said inner and outer tubes joining their extremities.
2. A strut for a tripod leg or the like as claimed in Claim 1 wherein said piston further comprises a piston ring or seal.
3. A strut for a tripod leg or the like as claimed in Claim 1 or Claim 2 wherein said sealing means is
**WARNING** end of DESC field may overlap start of CLMS **.

Claims (1)

  1. **WARNING** start of CLMS field may overlap end of DESC **.
    SPECIFICATION Improvements in or relating to tensioned struts This invention relates to tensioned struts and more particularly, though not exclusively, to tensioned struts for use on such as spreadable tripod legs.
    In the field of spreadable legs such as used on tripods etc. one of the main problems encountered is the difficulty of spreading the legs without the tripod and/or legs collapsing. The normal procedure is for each leg to have a locking or clamping device which has to be applied or released for each adjustment of each leg and unless this device is applied correctly to each tripod leg after adjustment the whole tripod is in danger of collapse and damage often occurs to valuable equipment mounted on the tripod. Various types of struts between the legs and tripod platform have been tried such as telescopic struts with clamps, turnbuckles and hinged struts but all these methods are time consuming, frustrating to the user and often nerve racking when expensive machinery is mounted on the tripod.
    It is therefore an object of this invention to provide a strut which may be used on such as a tripod which permits angular adjustment of the legs and reduces the possibility of tripod collapse and which would, under the worst conditions, where the load on the tripod is too heavy, sink slowly in a relatively vertical line to the position of all legs fully spread.
    According to the invention we provide a strut for a tripod leg or the like comprising, an outer tube having a means for pivotal location on one end, an inner tube of greater length than said outer tube and longitudinally movable therein having a means for pivotal location on its exposed end and a piston at its enclosed end longitudinally slidable within said outer tube, sealing means on said outer tube at its open end in sliding contact with said inner tube and an elastic cord within said inner and outer tubes joining their extremities.
    The invention will now be described by way of example, only in conjunction with the accompanying drawings in which: Figure 1 shows the cross section of a strut according to the invention in the closed position.
    Figure 2 shows a strut in a part extended and fully extended state and Figure 3 shows a graph of the approximate elastic cord forces, the approximate piston forces and the approximate required force curve.
    Referring to Figure 1 a tube (1), to which a vented plug (2) is fitted, has a bracket (3) for pivotal location oftube (1 ) at point A which represents a mounting position for a strut on a tripod platform, not drawn.
    Broken line BC represents a tripod leg pivotally located at point B on the tripod platform. A seal (4), such as an '0' ring or a pressed felt pad, is located in a groove in the bore of tube (1) near the open end of tube (1) and is a sliding fit over an inner tube (5) having a shoulder (6) which is a sliding fit in the bore of the outer tube (1). The shoulder (6) forms a piston to which a seal or ring (7) may be fitted so that, on extension of the strut, air in chamber (8) is compressed. Located in the opposite end of inner tube (5) is a vented plug (9) to which a bracket (10) isfitted for pivotally locating the strut, in its relaxed state, to a point D on the tripod leg.A length of elastic cord, also known as shock cord and shock absorber cord, (11) extends internally of the tubes (1 ) and (5) and is attached to the inner tube vented plug at one end and to the outer tube vented plug at the opposite end so that with the strut in the closed position the elastic cord (11) is in a relaxed state.
    Referring now to Figures (2) and (3) the tripod legs, only one drawn, are partly spread and the inner tube (5) pivoted at D has been partly withdrawn from the outer tube (1). The elastic cord (11) is now under a degree of tension and the air in chamber (8) is under a degree of compression. The combined effect of the tension and compression forces stop the leg from collapsing to its fully spread state, shown dotted.
    The greater the degree of spread of the leg the greater are the tension and compression forces as shown in Figure 3 where curve X represents the approximate reacting force due to compression of the air and curve Y represents, the approximate reacting force due to tension of the elastic cord.
    Curve Z represents the approximate required counteracting force and approximates the resultant reacting force, or combination of tension and compression, and the weight on the tripod platform tending to spread the legs is counteracted by the force tending to close the strut and is approximately proportional through the range of spread i.e. the forces acting at P1 balance out and also at P2.
    Though extremely stable the strut may be further supplied with a locking means so that during prolonged periods of use in one spread position, the strut would be doubly secure. The locking means may take many forms and a preferred method is the type known as a split block which would clamp over a portion of the exposed inner tube and would normally be fixed to the open end of the outer tube.
    Quick action clamping means for such split blocks are well known.
    By using this type of strut for tripod legs or the like the possibility of damage to equipment mounted on the tripod platform is greatly reduced and the struts on the tripod legs approximately balance the weight of an article on the tripod platform at any leg spread angle.
    1. A strut for a tripod leg or the like comprising, an outer tube having a means for pivotal location on one end, an inner tube of greater length than said outertube and longitudinally movable therein having a means for pivotal location on its exposed end and a piston at its enclosed end longitudinally slidable within said outer tube, sealing Heans on said outer tube at its open end in sliding contact with said inner tube and an elastic cord within said inner and outer tubes joining their extremities.
    2. A strut for a tripod leg or the like as claimed in Claim 1 wherein said piston further comprises a piston ring or seal.
    3. A strut for a tripod leg or the like as claimed in Claim 1 or Claim 2 wherein said sealing means is secured to the inside of said outer tube.
    4. A strut for a tripod leg or the like as claimed in any previous claim wherein said elastic cord is in a relaxed state when said inner and outer tubes are unextended.
    5. A strut for a tripod leg or the like as claimed in any previous claim where, in use, the resultant force provided by the combination of elastic cord and air compression approximates the required force, at any selected leg spread angle, to maintain the position of an article and tripod platform.
    6. A strut for a tripod leg or the like substantially as described and claimed herein in conjunction with the accompanying drawings.
    Amendments to the claims have been filed, and have the following effect: (a) Claims 1 and 5 above have been deleted or textually amended.
    (b) New or textually amended claims have been filed as follows: (c) Claim 6 above has been re-numbered as 5
    1. A strut for a tripod leg or the like comprising, an outer tube having a means for pivotal location on one end, an inner tube of greater length than said outer tube and longitudinally movable therein having a means for pivotal location on its exposed end and a piston at its enclosed end longitudinally slidable within said outer tube, sealing means on said outer tube at its open end in sliding contact with said inner tube and an elastic cord within said inner and outer tubes joining their extremities where, in use, the resultant force provided by the combination of elastic cord and air compression approximates the required force, at any selected leg spread angle, to maintain the position of an article and tripod platform.
GB8313949A 1983-05-20 1983-05-20 Extensible spring strut Expired GB2141204B (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
GB8313949A GB2141204B (en) 1983-05-20 1983-05-20 Extensible spring strut
DE19843417759 DE3417759A1 (en) 1983-05-20 1984-05-12 TENSIONING STRUTS FOR TRIPOD LEGS OR THE LIKE
FR8407557A FR2546268A1 (en) 1983-05-20 1984-05-16 IMPROVEMENTS IN SPACERS WORKING IN TENSION, ESPECIALLY FOR SHORT-SIDED LEG TRIPODS

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB8313949A GB2141204B (en) 1983-05-20 1983-05-20 Extensible spring strut

Publications (3)

Publication Number Publication Date
GB8313949D0 GB8313949D0 (en) 1983-06-29
GB2141204A true GB2141204A (en) 1984-12-12
GB2141204B GB2141204B (en) 1987-02-11

Family

ID=10543073

Family Applications (1)

Application Number Title Priority Date Filing Date
GB8313949A Expired GB2141204B (en) 1983-05-20 1983-05-20 Extensible spring strut

Country Status (3)

Country Link
DE (1) DE3417759A1 (en)
FR (1) FR2546268A1 (en)
GB (1) GB2141204B (en)

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB477674A (en) * 1936-04-27 1938-01-04 Ch Faure Roux Ets Improved shock-absorber
GB1020087A (en) * 1964-01-08 1966-02-16 Rene Roux Improvements in or relating to damping devices

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE78447C (en) * — langer & CO., Wien III, Hauptstr. 24 Tripod with multi-part legs
US3722847A (en) * 1972-03-01 1973-03-27 Connor C O Instrument support structure
GB1530332A (en) * 1976-03-13 1978-10-25 Vinten Ltd Balanced portable pedestals
DE3026533A1 (en) * 1980-07-12 1982-02-04 Abeg Apparatebau und Elektroanlagen GmbH, 8011 Kirchseeon Height adjustment for searchlight tripod - has telescopic tubes with ends closed by discs with throttling holes to control speed of extension

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB477674A (en) * 1936-04-27 1938-01-04 Ch Faure Roux Ets Improved shock-absorber
GB1020087A (en) * 1964-01-08 1966-02-16 Rene Roux Improvements in or relating to damping devices

Also Published As

Publication number Publication date
GB8313949D0 (en) 1983-06-29
FR2546268A1 (en) 1984-11-23
DE3417759A1 (en) 1984-11-22
GB2141204B (en) 1987-02-11

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