US2550099A

US2550099A - Flexible hose for suction cleaners

Info

Publication number: US2550099A
Application number: US98920A
Authority: US
Inventors: John E Vance
Original assignee: Hoover Co
Current assignee: Hoover Co
Priority date: 1949-06-14
Filing date: 1949-06-14
Publication date: 1951-04-24
Anticipated expiration: 1968-04-24

Description

April 24, 1951 J. E. VANCE 2,550,099

FLEXIBLE HOSE FOR SUCTION CLEANERS Filed June 14, 1949 2 Sheets-Sheet l INVENTOB.

John E. Vance ATTORNEY.

Aprii 24, 1951 Filed June 14, 1949 J. E. VANCE 2,550,099

FLEXIBLE HOSE FOR SUCTION CLEANERS 2 Sheets-Sheet 2 INVENTOR. John 1 Vimae ATTORNEY.

Patented Apr. 24, 1951 FLEXIBLE HOS-E FOR SUCTION CLEANERS John E. Vance, Canton, Ohio, assignor to The Hoover Company, North Canton, Ohio, a cor-' poration of Ohio Application June 14, 1949, Serial No. 98,920

6 Claims.

This invention relates to flexible hose for suction cleaners and to the method of making the same. v

A suction cleaner hose must be as flexible as possible for ease in manipulating the cleaning tools, it must be rigid against compressive stresses so as to resist collapse when accidentally trod upon or placed beneath articles of furniture, and the impervious wall must be supported against collapse due to the suction applied on its interior.

According to the present invention the impervious tube comprises an elastomeric thermoplastic such as polyvinyl chloride or copolymer of vinyl of about 0.026 inch in thickness and about 1% inches inside diameter. A spirally wound reinforcing wire of spring steel is positioned interiorly of the tube and a vinyl chloride cord is wrapped spirally over the tube between the convolutions of the wire under sufficient tension to draw the material of the tube inwardly between the wire convolutions so as to render the completed hose more flexible.

According to the method of this invention the steel spring is spirally wound in suitable lengths with a pitch of substantially inch. The spring is preferably originally wound on a mandrel of somewhat smaller diameter than the diameter of the desired coil. (In making suction cleaner hose it has been found that a final inside diameter of approximately 1% inches is suitable.) When the coil is released it will expand to the proper diameter under its own resiliency.

The spiral spring thus formed is placed on a mandrel having a diameter a few thousandths of an inch smaller than the free inside diameter of the coil and one end taped to the mandrel, or to a fitting sleeve anchored to the mandrel, preferably by a pressure sensitive tape. The pitch of the coil in its free state is slightly less than it is in the finished hose as is the number of its convolutions.

Aspacing tool is then applied to the taped end of the coil and the mandrel rotated reversely to expand the pitch of the coils axially and to space them equidistant and to tightly grip the mandrel while at the same time the tool applies a contracting effect spirally upon the coils as they are spaced to wind the coils closely about the mandrel with the result that there is a greater number of loops formed than that which was present in the coil in its free state. The combined effect of spacing the coils a greater distance apart and the forming of additional loops cause the coils to tightly grip the mandrel so that each loop is substantially immovable axially 2 of the mandrel. After the spacing operation theother end of the coil is suitably attached to the mandrel or to a coupling fitting tube positioned on the mandrel.

An electromeric thermoplastic tube is then applied over the mandrel and spring, in any suitable manner, such as by expanding it by air pressure and sliding it axially over the mandrel and the spiral spring positioned thereon.

A few turns of the vinyl cord are then wrapped by hand over the vinyl tube at one end midway of the convolutions of the wire and taped to the tube preferably by a pressure sensitive tape. The mandrel, wire, and tube are then rotated while a tensioning device holding the cord. is advanced axially to wind the cord about the tube midway of the wire convolutions. When the cord applying operation is completed the free end of the cord is severed and taped to the tube at the other end by means of a pressure sensitive tape.

. Preferably, a suitable solvent is simultaneous- 1y applied to the tube a few turns ahead of the cord during the winding operation to cement the cord to the tube midway ofthe wire convolutionsso that the cord cannot be moved from between one wire convolution to an adjacent one or vice versa. I

The vinyl cord is stretched slightly by the tensioning device so that when the tube is removed from the mandrel the coils of the vinyl cord will contract to press the walls of the tube inwardly between the wire convolutions to form a corrugated effect and render the tube more flexible.

t the same time the convolutions of the wire will tend to return to their original pitch and number so that the coils will expand outwardly by an amount permitted by the elasticity of the vinyl tube and cord.

The tube preferably extends beyondthe ends of the wire and vinyl cord and is turned backwardly over the tube and vinyl cord so as to permit an attaching fitting to be applied.

Other objects and advantages of this invention will become apparent as the description proceeds when taken in connection with the accompanying drawings in which:

Figure 1 shows a schematic view of the machine for spacing the wire coils on the mandrel and for winding the vinyl cord about the tube;

Figure 2 is a detailed view showing the operation of the spacing nut;

Figure 3 is a plan view of the spacing device showing how it is mounted on the machine; and

Figure 4 is a longitudinalacross-sectionalview through the tube of this invention showing one form of an attachment coupling applied thereto.

Referring to Fig. 4 the hose of this invention comprises an inner spirally wound spring wire I stressed axially and spirally from its normal unstressed state, an elastomeric thermoplastic vinyl tube II positioned thereover and forced between the convolutions of the wire I0 by a spirally wound elastomeric thermoplastic vinyl cord I2.

The end connection for the hose may take any suitable form but as shown in Fig. 4 comprises an inner swivel tube I3, an outer swivel tube I4 having a swivel connection with the inner tube I3 generally indicated by the reference numeral I 5 in the form of inwardly pressed annular grooves in the tubes. the wire I0 rests in the groove of the outer swivel tube I4. The few end turns of the wire I0 are secured to the tube I4 by a pressure sensitive tape I? spirally wound over the wire. Near its end the tube II is anchored to the tube I4 over the end I6 of wire Ii] by waxed threads [8. The threads I8 and the end coils of the cord 12 are secured to the tube II by a pressure sensitive tape I0. The end 20 of the tube I I is then turned backwardlyover the threads I8, tape I9, and the first few coils of cord I2 and a phenolic or other plastic sleeve 2I attached to the inner swivel sleeve I3 so as to surround the end 20 of the tube I I as shown in Fig. 4. It is within the scope of this invention that other types of end couplings be used, the one of Fig. 4 being shown as an example.

The hose of Fig. 4 is formed by any suitable apparatus such as the machine of Fig. 1 generally indicated by the reference numeral 30, similar to a turning lathe. The machine comprises a bed plate 3|, a head stock 32, a tail stock 33, a

lead screw 34, and a traveling carriage 35 connectible to the lead screw 34 by a manually actuatable clutch 36 in. a manner similar to an ordinary turning lathe. The driving mechanism for the head stock 32 and for the lead screw 34 are geared to both in a manner similar to an ordinary turning lathe. A mandrel 31 is rotated by thehead stock 32 and is rotatably mounted by the tail stock 33.

The'carriage 35 carries a coil spacing device generally indicated by the reference numeral 43, a reel. holder M for carrying a reel of vinyl cord, a tensioning pulley 42, and a cord tension measuring device 43. Carriage 35 is also provided with suitable guide pulleys to guide the cord from the reel M to the tensioning pulley 42, fromthe tensioning pulley 42 to the tension measuring device 43 and from the tension measuring device to the mandrel 31. The tension measuring device 43 includes a clocklike dial and hand which register the tension on the cord to constantly inform theoperator of the tension applied. 1 It has been found in the example given that a tension of 56 to 64 ounces is satisfactory for the conditions specified. a a I The spring spacing device 40 includes a sort of nut 45 split axially to form two halves 46 and 41, the lower half 46 being secured to the traveling carriage 35 by means of a supporting lug 48.

The two halves of the nut 45 are provided with spiral grooves 49 in the nature of screw threads but circular in cross-section to fit snugly over the wire ID. The pitch of the grooves 49 is somewhatv greaterthan that of the, convolutions of the wire' III. in its free-state for a purpose which will-presentlyappear;........ Q'I

The end I6 of elastomeric thermoplastic vinyl tube.

The two halves46 and 41 of nut 45 are pivoted together and to the support 48 at 55, the lower half 45 being slotted at 5| on the side opposite the pivot 50 to receive a clamping bolt 52 pivoted to the upper half 47 as shown in Fig. 3.

The carriage 35 may also carry a solvent applying dispenser in the form of a container as shown in Fig. 1 having a valved tube leading to a point immediately above the mandrel at a point a few turns ahead of where the cord is wrapped about the mandrel. The solvent used may be a 50-50 by volume mixture of toluene and methyl ethyl ketone.

Method of forming hose A steel spring wire of suitable diameter is spirally wound into a coil of substantially the same internal diameter'as the diameter of mandrel 3'3 and with a pitch slightly less than that of the wire If) in the finished hose. The wire is preferably wound on a mandrel slightly smaller than the mandrel 3'! so that when it is released the coils will expand to the proper diameter and pitch.

It has been found in practice that a wire hav ing a diameter of 0.058 inch and a tensile strength of 275,000 pounds per square inch is suitable. The free diameter of the coil should be close to 1% inches and have a pitch of approximately inch.

Coupling sleeves similar to the sleeves I3 and H! are positioned on the mandrel at the head stock end thereof. The wire coil is placed on the mandrel 31, which in practice is approximately 1 inches in diameter, the sleeves I3 and I4 slid onto the tail stock end of the mandrel beneath the wire coils with the end coil I6 positioned in the peripheral groove I5, it being noted, Fig. 4, that the inside diameter of the inner end of tube I4 is substantially the same as the inside diameter of tube I3 whereby they can be positioned on the mandrel. The wire II] is taped to the sleeve I4 by the pressuresensitivetape II at the tail stock end thereof and the sleeves I3, and I4 anchored against rotation relative to the mandrel.

.The turns of the wire on the sleeve and the first'few turns on the mandrel are suitablyspaced by hand or otherwise and the spacing nut 45 arranged over the turns with the wire lying in' the spiral grooves 49. It has been found in practice that the pitchof the spiral grooves in'the nut 45 should be about 0.286 inch when the normal free pitch of the wire coils is inch.

The diameter of the spacing nut and the depth of the grooves 49 is such that the nut will grip the wire coils quite firmly when the bolt .52 is clamped.

' After the nut 45 is applied to the first few coils of wire positionedon the mandrel at the tail stock end, the clutch 33 is manually operated to engage the carriage 35'with the lead screw 34 and the head stock 32 rotated forward or counterclockwise as viewed from the tail stock end.

Such rotation of the arbor will cause the coils to be spaced uniformly thereon and the gripping action of the nutwill also deform or stress the coils circumferentially so that under the condi: tions given above there will be approximately one percent more coils formed on the mandrel than there are in the coiled wire in its unstressed state. The foregoing action will cause the coils to grip the mandrel tightly so that they will'not move during the subsequent application of the When the spacing nut reaches the left hand end of the mandrel, to the sleeve positioned thereon, the few end turns of the coiled wire are tightly taped to a sleeve I4 by pressure sensitive tape and the sleeve clamped to the mandrel in any suitable manner.

. Tail stock 33 may then be removed and a vinyl tube applied by air pressure in a manner disclosed in a copending application by John E. Vanceand Dale C. Gerben'Serial No. 787,544, filed November 22, 1947. According to that application a tapered sleeve having an inside diameter of a size suitable to slide over the coiled wire on the mandrel is inserted into the end of a vinyl tube having an inside diameter substantially the same as the diameter of the mandrel and air pressure applied to its opposite end. The air pressure expands the tube sufiiciently that it can be slid axially over the coiled wire positioned on the mandrel. It is to be noted from Fig. 4 that the length of the tube I I should be greater than that of the coiled wire on the mandrel by an amount sufficient to form the backwardly extending portions 20 at each end.

An alternate method is to make the mandrel 3'I hollow and apply air pressure to the interior thereof through the head stock 32 and plug the free end of the tube so that air pressure will expand the tube sufficiently that it can be slid over the coiled wire.

It has been found that a plastic tube, having a wall thickness of 0.026 inch, formed of elastomeric thermoplastic vinyl having a minimum tensile strength of 2,000 pounds per square inch at 80 F. is suitable,

The tail stock 33 is then reengaged with the mandrel 31, the first few coils of the cord I2 wound over the tube II and sleeves at the head stock end of the mandrel midway between the convolutions of the wire I0. The end of the tube II is also rigidly secured to the sleeves and the wire 50 by means of waxed threads Ill. The first few turns of the cord I2 and threads I3 are taped to the tube I I by pressure sensitive tape I9.

It has been found that a plastic cord of elastomeric thermoplastic vinyl having a minimum tensile strength of 2,000 pounds per square inch at 80 F. and a diameter 0.075 inch is suitable.

The tension on the cord is properly adjusted by adjusting the tensioning pulley :2, which tension will be registered on the tension measuring device 43. The clutch 36 is then manually operated to engage the carriage 35 with the lead screw 34 and the head stock 32 rotated backwardly or clockwise as viewed from the tail stock end so as to spirally wind the cord over the tube I I midway between the convolutions of the reinforcing wire I0 from the head stock end to the tail stock end of the mandrel 31. The end coils of the cord are then taped to the tube II by a pressure sensitive tape I9. During the Winding of the cord I2 about the tube II the valve in the solvent dispensing tube is properly adjusted to apply the proper quantity of solvent two or three coils ahead of the cord as the cord is wound about the tube. The solvent is applied sufiiciently ahead of the point where the cord is being wound to permit the surface of the tube to soften sufiiciently that the cord will firmly adhere to the tube as it is wound about it.

The tail stock 33 is again removed and the finished tubing removed from the mandrels 3'! by applying a twisting action in a direction to expand the coils I0 whereby the finished tube can 6 be slid backwardly off the tail stock end of the mandrel 31.

The tension applied to the cord I2 will force the walls of the tube I I inwardly between the convolutions of the wire I0. Additionally, the wire spiral I0 will tend to return to its original pitch and diameter so as to force the tube I I outwardly' between the convolutions of the cord I2 a distance permitted by the elasticity of the tube wall and of the cord so as to form a very flexible hose." I

The end couplings 2I may then be applied to each end of the hose in any suitable manner, note being taken that the end 20 of the tube I I is turned backwardly over the end coils of the cord l2.

Elastomeric thermoplastic materials as such are old and well known and are made by mixing a thermoplastic resin with a plasticizer. At ordinary temperatures they are slightly elastic in that the material can be stretched somewhat and will return when released. If the material remains in stretched condition it will remain under a definite tension.

While I have shown and described but a single embodiment of the hose and method of my invention it is to be understood that this embodiment is to be taken as illustrative only and not in a limiting sense. I do not wish to be limited to the particular structure shown and described but to include all equivalent variations thereof except as limited by the scope of the claims.

I claim:

1. A flexible hose comprising, a coiled spirally wound reinforcing spring wire, a single thickness tube of elastomeric thermoplastic material having a normal internal diameter substantially the same as the unstressed internal diameter of said spiral positioned over said spiral and an elastomeric cord wound spirally over said tube between the convolutions of said spiral, the coils of said spiral being under both axial, diametric and circumferential stress tending to shorten the pitch and increase the diameter of the coils of said spiral to force the walls of said tube outwardly between the convolutions of said cord, said elastomeric cord being under circumferential tension tending to decrease the internal diameter of its coils and force the walls of said tube in- Wardly between the convolutions of said spiral and said elastomeric tube being under axial stress tending to resist the action of said spring and cord whereby said tube assumes a corrugated formation.

2. A flexible hose comprising, a coiled spirally wound reinforcing spring the coils of which are under both axial and circumferential stress, a single thickness axially and diametrically expanded elastomeric vinyl tube surrounding said spiral and having an unstressed internal diameter substantially the same as the unstressed internal diameter of said spiral and an elastomeric vinyl cord wrapped under circumferential tension about said tube between the convolutions of said spiral.

3. A flexible hose according to claim 2 in which said cord is bonded to the exterior of said tube by a solvent applied to said tube beneath said cord.

4. A flexible hose consisting of an inner expanded coiled spirally wound reinforcing wire, a single thickness tube of slightly elastic elastomeric thermoplastic material closely surrounding said spiral and a cord of the same material as said tube Wound spirally under tension over said tube between the convolutions of said spiral.

5. A flexible hose according to claim 4 in which said tube and cord are made of elastomeric polyvinyl chloride.

6. A flexible hose according to claim 4 in which said cord is bonded to said tube over its entire length.

JOHN E.-VANCE.

REFERENCES CITED Number 8 UNITED STATESPATENTS Name Date Shackleton Nov. 29, 1887 Voorhees Feb. 4, 1913 Ramsdell Sept. 5, 1939 Forbes Oct. 17, 1939 Wilkinson et a1. Jan. 12, 1943 Chernack Feb. 1, 1944 Baymiller Dec. '7, 1948 Murphy May 2, 1950