Title:
Method of forming a stachion assembly
United States Patent 3911549
Abstract:
A tubular member having at least one bulbous formation along the length thereof such as in the case of a stanchion, the bulbous formation being covered by a preferably rigid element which conforms in shape to the bulbous formation.
US Patent References:
Coupling
Rood - August 1949 - 2479702
Tubular joint
Peach et al. - October 1952 - 2614827
Method of making tube-to-flange connection
Meyer - November 1954 - 2695446
Pipe expanding tool
Mueller - March 1955 - 2704104
Method of forming ball and socket joints in metal tubular members
Hopkins - October 1961 - 3002269
Coupling
Rood - August 1949 - 2479702
Tubular joint
Peach et al. - October 1952 - 2614827
Method of making tube-to-flange connection
Meyer - November 1954 - 2695446
Pipe expanding tool
Mueller - March 1955 - 2704104
Method of forming ball and socket joints in metal tubular members
Hopkins - October 1961 - 3002269
Application Number:
05/428626
Publication Date:
10/14/1975
Filing Date:
12/27/1973
View Patent Images:
Export Citation:
Assignee:
Midland Industries, Ltd. (Wolverhampton, EN)
Primary Class:
Other Classes:
285/382.500, 29/507, 29/423, 29/445, 256/21, 29/523
International Classes:
B21D26/02; B21D39/06; B23P17/00; B21D26/00; B21D39/00; B23P17/00
Field of Search:
29/523,423,507,421,445 138/172 285/382.4,382.5 256/21,22
US Patent References:
| 3776523 | STRUCTURAL TUBE ASSEMBLY | December 1973 | Weiland |
Primary Examiner:
Moon, Charlie T.
Attorney, Agent or Firm:
Mason, Fenwick & Lawrence
Parent Case Data:
This is a division, of application Ser. No. 289,972, filed Sept. 18, 1972, now abandoned.
Claims:
I claim
1. A method of forming a stanchion assembly having a strengthened joint for a horizontal rail member comprising the steps of providing a separate hollow bulbous element having at least one hole in the wall thereof, passing an end of a first tubular member into the hole in the bulbous element, expanding the section of the first tubular member enclosed by the bulbous element into conforming contact throughout with the inner surface of the bulbous element, forming an opening at an angle to the first tubular member through the bulbous element and the first tubular member to receive a second tubular member, and passing the second tubular member through said opening to form the horizontal rail member of a stanchion assembly.
2. A method as claimed in claim 1 in which the bulbous element is a rigid element.
3. A method as claimed in claim 1 in which the expansion is carried out in the cold state.
1. A method of forming a stanchion assembly having a strengthened joint for a horizontal rail member comprising the steps of providing a separate hollow bulbous element having at least one hole in the wall thereof, passing an end of a first tubular member into the hole in the bulbous element, expanding the section of the first tubular member enclosed by the bulbous element into conforming contact throughout with the inner surface of the bulbous element, forming an opening at an angle to the first tubular member through the bulbous element and the first tubular member to receive a second tubular member, and passing the second tubular member through said opening to form the horizontal rail member of a stanchion assembly.
2. A method as claimed in claim 1 in which the bulbous element is a rigid element.
3. A method as claimed in claim 1 in which the expansion is carried out in the cold state.
Description:
This invention relates primarily to stanchions and the like supports for rails such as hand and knee rails, but also to any other tubes which have bulbous formations along the length thereof.
Generally, in the case of hand and knee rails, the rails are suppported in stanchions having holes, provided along the length of the stanchion, through which the rails are passed. As the external diameter of the rail generally approximates the external diameter of the stanchion, it has become practice to enlarge the stanchion at its point of support and then to form holes of suitable diameter in the enlarged bulbous portion.
Various methods have been proposed for enlarging the stanchion at its point of support. One method provides for the stanchion to be heated at this point and then expanded under the action of a high gas pressure while the stanchion is rested between co-acting dies. The stanchion expands to assume, complementarily the profile of the dies.
This method suffers from the disadvantage that the piping from which the stanchions are manufactured is not suitable for such expansion and there is a high loss through bursting of the expanded stanchion walls. This is a particularly serious problem if two or more enlargements are to be provided on the same stanchion, as bursting may occur when the final enlargement is being carried out, resulting not only in loss of material but time and effort.
In order to overcome these difficulties, other methods have been proposed. One method provides for sections of suitable piping to be spun and then developed to a funnel shape at one or more of the pipe extremities. The expanded extremities of two pipes are then brought together and welded according to known techniques to provide the bulbous formation. This method is costly not only because of the need for welding by skilled, or at least, semi-skilled operators, but also because a finishing operation is required.
In another method, discs are shaped into hemispherical formations which are then butt-welded together. Tubes are then welded to opposite sides of the bulbous formation so formed. This method suffers from the same disadvantage mentioned above.
An object of the present invention is the provision of improved tubular members having bulbous portions thereon and of a method of forming bulbous portions in tubular members which will reduce the effect of the disadvantages referred to above.
According to this invention there is provided a tubular member having a bulbous portion thereon, the bulbous portion being covered by means of an element which conforms to the shape of the bulbous portion.
A further feature of the invention provides for the cover element to be either a deformable plastics element or a rigid bulbous element.
According to the present invention a method of forming a bulbous portion on a tubular member includes the steps of providing a separate hollow bulbous element having at least one hole in the wall thereof, passing an end of a tubular member into or through the hole or holes in the element and causing the section of the tubular member enclosed by the bulbous element to expand into contact with the inner walls of the element.
Preferably expansion takes place in the cold by use of known techniques. Preferably also the bulbous elements are formed by die-forming short lengths of pipe in the cold to the desired shape.
By way of example, preferred forms of the invention will now be described as applied to the manufacture of stanchions, reference being made to the accompanying drawings in which:
FIG. 1 is a section through a partly-completed stanchion according to the invention; and
FIG. 2 is a perspective view of a bulbous element employed in carrying the invention into effect.
Bulbous elements 1 are firstly cold formed in a pair of complementary hemispherical dies through which a mandrel passes, the elements being formed from predetermined short lengths of pipe having an external diameter roughly equal to the diameter of the completed bulbous element. The mandrel is slightly larger in diameter than the pipe to be used for the stanchions and thus defines two opposed holes through the resultant spherical elements.
In the next operation one or more of the above bulbous elements 1 are slipped over a pipe of desired length and positioned at the points where rails are to be supported thereby. Thus in the stanchion example shown in FIG. 1, one bulbous element 1 is positioned midway along the length of the pipe and one towards its extremity. The pipe is then suitably clamped in the confines of dies which fit neatly over the bulbous elements simply to prevent these from becoming deformed and which support the outside surface of the pipe between the bulbous elements. One end of the pipe is sealed off by means of a mandrel and a pressure is applied to the other end through known ram means to cause the portions of the pipe within the bulbous elements to expand into contact with the inside surface of said bulbous elements.
Whilst the above-described expansion operation may be effected as described, it has been found that it is advantageous to provide a deformable inner liner to the pipe for this operation. Thus, a polyurethane tube or rod is preferably inserted into the pipe prior to the expansion operation and this assists in the sealing of the one end of the pipe and the distribution of the pressure on the pipe walls. If such a liner is used, it is removed after the expansion operation.
Alternatively, deformable metal plugs may be located in the pipe in the portions within the bulbous elements and these are then caused to expand the pipe by means of suitable plungers. The metal which is a low melting point alloy may be melted out for reuse.
The bulbous elements are now positively locked in position and the stanchion is ready for further treatment.
It will be appreciated that the top end of the stanchion so formed remains open. This can be closed off in a number of ways. The bulbous elements may thus be formed with one hole approximating the exeternal diameter of the pipe and the other diametrically opposite holes having a much smaller diameter. In this case the pipe does not extend through the bulbous formation but bears against the interior walls of the formation in the zone of the smaller hole. The smaller hole is then closed off according to conventional methods, for instance, by welding. In another method of closing off the upper end of the stanchion, a disc is pressed out and welded in position on top of the pipe, the disc's outer face forming a continuation of the outer surface of the bulbous element. This latter method is illustrated in FIG. 1, the disc being numbered 3.
The invention has the advantage that any bursting that occurs during expansion of the stanchion pipe is hidden by the bulbous elements and the stanchion need not be discarded. At the same time the bulbous element acts to strengthen the burst walls if this does occur.
Furthermore, it will be appreciated that the walls of the pipe have to be expanded sufficiently so that when a hole is formed in them, an unduly weakened stanchion does not result. It may be that expansion, according to prior art methods, takes the walls to the stage where they border on bursting. This is overcome in the present invention in which the pipe walls do not have to be expanded as far as would have been the case had no bulbous elements been provided. In this way, it is felt that the fraction of pipes bursting during the expansion operation will be cut down appreciably.
Many forms of the invention exist and the above description is therefore given by way of example only. Although preference is given to an expansion operation employing polyurethane, doubtless other plastics material and rubbers could be used. It is envisaged that sand or even lead billets may be employed. Although cost requirements provide for a cold expansion process, the invention is not limited to this and under certain conditions it may be found advantageous to expand the metal while in a heated condition. The bulbous formations may be formed en masse as set out above from a length of pipe or may be formed singly.
Whilst it is preferred to use a rigid cover element for the bulbous part of the stanchion pipe, in some cases it may be sufficient to provide a deformable cover over the bulbous portions simply to hide any burst areas. Such a cover could simply be a plastics or rubber sleeve over the bulbous portions.
The invention therefore provides a simple method and means for avoiding the necessity of disposing of burst stanchion pipes.
Generally, in the case of hand and knee rails, the rails are suppported in stanchions having holes, provided along the length of the stanchion, through which the rails are passed. As the external diameter of the rail generally approximates the external diameter of the stanchion, it has become practice to enlarge the stanchion at its point of support and then to form holes of suitable diameter in the enlarged bulbous portion.
Various methods have been proposed for enlarging the stanchion at its point of support. One method provides for the stanchion to be heated at this point and then expanded under the action of a high gas pressure while the stanchion is rested between co-acting dies. The stanchion expands to assume, complementarily the profile of the dies.
This method suffers from the disadvantage that the piping from which the stanchions are manufactured is not suitable for such expansion and there is a high loss through bursting of the expanded stanchion walls. This is a particularly serious problem if two or more enlargements are to be provided on the same stanchion, as bursting may occur when the final enlargement is being carried out, resulting not only in loss of material but time and effort.
In order to overcome these difficulties, other methods have been proposed. One method provides for sections of suitable piping to be spun and then developed to a funnel shape at one or more of the pipe extremities. The expanded extremities of two pipes are then brought together and welded according to known techniques to provide the bulbous formation. This method is costly not only because of the need for welding by skilled, or at least, semi-skilled operators, but also because a finishing operation is required.
In another method, discs are shaped into hemispherical formations which are then butt-welded together. Tubes are then welded to opposite sides of the bulbous formation so formed. This method suffers from the same disadvantage mentioned above.
An object of the present invention is the provision of improved tubular members having bulbous portions thereon and of a method of forming bulbous portions in tubular members which will reduce the effect of the disadvantages referred to above.
According to this invention there is provided a tubular member having a bulbous portion thereon, the bulbous portion being covered by means of an element which conforms to the shape of the bulbous portion.
A further feature of the invention provides for the cover element to be either a deformable plastics element or a rigid bulbous element.
According to the present invention a method of forming a bulbous portion on a tubular member includes the steps of providing a separate hollow bulbous element having at least one hole in the wall thereof, passing an end of a tubular member into or through the hole or holes in the element and causing the section of the tubular member enclosed by the bulbous element to expand into contact with the inner walls of the element.
Preferably expansion takes place in the cold by use of known techniques. Preferably also the bulbous elements are formed by die-forming short lengths of pipe in the cold to the desired shape.
By way of example, preferred forms of the invention will now be described as applied to the manufacture of stanchions, reference being made to the accompanying drawings in which:
FIG. 1 is a section through a partly-completed stanchion according to the invention; and
FIG. 2 is a perspective view of a bulbous element employed in carrying the invention into effect.
Bulbous elements 1 are firstly cold formed in a pair of complementary hemispherical dies through which a mandrel passes, the elements being formed from predetermined short lengths of pipe having an external diameter roughly equal to the diameter of the completed bulbous element. The mandrel is slightly larger in diameter than the pipe to be used for the stanchions and thus defines two opposed holes through the resultant spherical elements.
In the next operation one or more of the above bulbous elements 1 are slipped over a pipe of desired length and positioned at the points where rails are to be supported thereby. Thus in the stanchion example shown in FIG. 1, one bulbous element 1 is positioned midway along the length of the pipe and one towards its extremity. The pipe is then suitably clamped in the confines of dies which fit neatly over the bulbous elements simply to prevent these from becoming deformed and which support the outside surface of the pipe between the bulbous elements. One end of the pipe is sealed off by means of a mandrel and a pressure is applied to the other end through known ram means to cause the portions of the pipe within the bulbous elements to expand into contact with the inside surface of said bulbous elements.
Whilst the above-described expansion operation may be effected as described, it has been found that it is advantageous to provide a deformable inner liner to the pipe for this operation. Thus, a polyurethane tube or rod is preferably inserted into the pipe prior to the expansion operation and this assists in the sealing of the one end of the pipe and the distribution of the pressure on the pipe walls. If such a liner is used, it is removed after the expansion operation.
Alternatively, deformable metal plugs may be located in the pipe in the portions within the bulbous elements and these are then caused to expand the pipe by means of suitable plungers. The metal which is a low melting point alloy may be melted out for reuse.
The bulbous elements are now positively locked in position and the stanchion is ready for further treatment.
It will be appreciated that the top end of the stanchion so formed remains open. This can be closed off in a number of ways. The bulbous elements may thus be formed with one hole approximating the exeternal diameter of the pipe and the other diametrically opposite holes having a much smaller diameter. In this case the pipe does not extend through the bulbous formation but bears against the interior walls of the formation in the zone of the smaller hole. The smaller hole is then closed off according to conventional methods, for instance, by welding. In another method of closing off the upper end of the stanchion, a disc is pressed out and welded in position on top of the pipe, the disc's outer face forming a continuation of the outer surface of the bulbous element. This latter method is illustrated in FIG. 1, the disc being numbered 3.
The invention has the advantage that any bursting that occurs during expansion of the stanchion pipe is hidden by the bulbous elements and the stanchion need not be discarded. At the same time the bulbous element acts to strengthen the burst walls if this does occur.
Furthermore, it will be appreciated that the walls of the pipe have to be expanded sufficiently so that when a hole is formed in them, an unduly weakened stanchion does not result. It may be that expansion, according to prior art methods, takes the walls to the stage where they border on bursting. This is overcome in the present invention in which the pipe walls do not have to be expanded as far as would have been the case had no bulbous elements been provided. In this way, it is felt that the fraction of pipes bursting during the expansion operation will be cut down appreciably.
Many forms of the invention exist and the above description is therefore given by way of example only. Although preference is given to an expansion operation employing polyurethane, doubtless other plastics material and rubbers could be used. It is envisaged that sand or even lead billets may be employed. Although cost requirements provide for a cold expansion process, the invention is not limited to this and under certain conditions it may be found advantageous to expand the metal while in a heated condition. The bulbous formations may be formed en masse as set out above from a length of pipe or may be formed singly.
Whilst it is preferred to use a rigid cover element for the bulbous part of the stanchion pipe, in some cases it may be sufficient to provide a deformable cover over the bulbous portions simply to hide any burst areas. Such a cover could simply be a plastics or rubber sleeve over the bulbous portions.
The invention therefore provides a simple method and means for avoiding the necessity of disposing of burst stanchion pipes.