The invention refers to a device for tensioning a drawcord extending along a hem of a cover for an ironing board underneath the ironing board, comprising a drum pivoted around an axis of rotation, which is surrounded by a lateral surface for winding up the drawcord.
A generic device is disclosed in
US 1,586,442. According to this former invention, in order to fix a cover to an ironing board, a plate is secured at the underside of this board, and a drum is journaled on said plate. A handle allows a person to rotate said drum for the purpose of winding the drawcord of said cover around the drum, whereby the,drawcord shall be tensioned in order to fix the cover at the ironing board. On the other hand, there is no possibility to anchor the drawcord to the drum, and as a result, the drawcord will always tend to slip along the lateral surface of the drum instead of being wound around the drum. After a full rotation at the earliest, an inner winding can be pressed against the lateral surface of the drum by an outer winding, thereby installing a frictional engagement between the cord and the drum.
From the disadvantages of the state of the art, the problem initiating the invention arises, namely to improve a device for tensioning a cord of an ironing board cover in that it can be anchored to a drum with less effort in such a way that it will not slip alont the lateral surface in case of a rottion of the drum, but will be wound around the drum in a detachable way.
The solution of this problem is achieved in that a through-hole passes through the drum perpendicularly to the axis of rotation for threading in the ends of the drawcord in order to anchor them to the drum.
The through-hole allows a person to thread one or both ends of a cord transversely through the drum and to hold it in tight contact with the lateral surface of the drum when the latter is rotated. As the cord extends completely through the drum, even in the case of only one cord end threaded through the drum, both strands of one cord end, which extend on both sides of the through-hole, will be wound on the lateral surface of the drum simultaneously, and therefore, after a half rotation of the drum, an outer strand winding will superimpose an inner strand winding and thereby securing the cord to the drum in a frictionally engaged manner.
It has been proved to be advantageous that the drum has an elongated shape. Such a design ensures that the perimeter of the drum is rather small, and therefore, only a small length of a drawcord has to be wound up in order to fix the drawcord to the drum.
The through-hole should have an elongated cross-section, whose longest extention is parallel to the longitudinal axis of the drum. Due to such an arrangement, both ends of the drawcord of the ironing board cover can be threaded through this through-hole simultaneously or side by side, respectively.
In order to improve the handling of the device according to the invention, the length of the cross-section of the through-hole should be sized at least 1.5 times larger than the greatest width of the cross-section of the through-hole, or at least 2 times larger than the width of the cross-section of the through-hole. Then, every drawcord can be threaded twice into such through-hole, which has a cross-section equal to or less than half of the cross-section of the through-hole.
Sharp edges between the through-hole and the lateral surface of the drum should be avoided in order to prevent a cutting or ripping of the drawcord at such an edge. Therefore, these edges can be rounded, or can be rounded with a radius of curvature of at least 0.5 mm.
Further advantages can be achieved, if the lateral surface of the drum extends between to end faces of the drum and tapers from these end faces to the middle of the drum, especially along two conical surfaces. Then, the windings of the drawcord on the drum will be concentrated at the middle of the drum, and the second winding will overlie the first winding and will press it against the lateral surface of the drum in a frictionally engaged manner.
The lateral surface of the drum can be delimited in the longitudinal direction by projecting flanges at one or both end faces of the drum. Such flanges ensure that the drawcord cannot slip from the drum at its end faces.
In order to stabilize the orientation of the axis of rotation of the drum as well as its actual angular positioning, the drum should be rotatably mounted in a chassis or housing.
For the arrangement of a first bearing between the drum and the chassis or housing, the latter may comprise at least a first plate with a circular hole for receiving a portion of the drum in such a way that the longitudinal axis of the drum is perpendicular to the plane of the plate.
Additionally, the chassis or housing may comprise a second plate which is parallel to the first plate, and both plates comprise a circular hole each which are in alignment with each other for receiving a portion of the drum. In such a way, the drum is mounted at or near its two end faces and thereby, the axis of rotation is fixed in an untiltable manner with regard to the chassis or housing.
The invention recommends that the distance between the turned-away sides of the first and second plates should be no more than the distance between the facing sides of the flanges at both end faces of the drum. In this case, it is possible to arrange the flanges at both end faces of the drum beyond the turned-away sides of the first and second plates of the chassis or housing, and then, the drum is mounted rotatable around the axis of rotation, but cannot be displaced along the direction of the axis of rotation.
A similar, but more complicated embodiment can be realized, if the distance between the turned-away sides of the of the flanges at both end faces of the drum is no more than the distance between the facing sides of the first and second plates. In this case, it is possible to arrange the flanges at both end faces of the drum between the facing sides of the first and second plates of the chassis or housing, and then, the drum cannot be displaced along the direction of the axis of rotation, too, while the bearing of the drum has to be done in a different manner in this case.
A way to hold the first and second plates at a constant distance is by use of a lateral surface of a housing, which, in combination with the first and second plates, forms a first chamber receiving and housing the drum in a rotatable manner. The first and second plate can be formed integrally with the lateral surface of the housing or can be connected thereto, for example by adhesive.
In order to be able to wind the drawcord onto the drum rotatably mounted inside the first chamber, the lateral surface of the first chamber housing the drum should be provided with two aligned holes, which can be futher aligned with the through-hole of the drum at a special angular position of the drum relative to the housing. The cross-section of each of these holes can be similar or identical to the cross-section of the through-hole in the drum.
The winding of the drawcord onto the drum is achieved by rotating the drum relative to the housing. This can be done by use of a twist grip attached to the drum in the area of one end face of the drum, either at the outside of the regarding end face, or at the outside of a flange at the regarding end face, or beyond a first plate of the chassis or housing near the regarding end face of the drum.
The device according to the invention can be further improved by providing the chassis or housing with a third plate beyond the second plate, wherein the third plate is parallel to the second plate. These second and third plates can be held at a constant distance by a lateral surface of the housing, which, in combination with the second and third plates, forms a second chamber for receiving additional mechanical elements of the device according to the invention.
Such an additional mechanical element of the device according to the invention may be a ratchet mechanism, which enables a rotation of the drum around the axis of rotation only in one direction. After winding the drawcord onto the drum by rotating the latter in the direction of rotation permitted by the ratching mechanism, this ratchet mechanism will lock the actual position of the drum against a rolling back, and therefore, the drawcord cannot unwind from the drum spontaneously.
On the other hand, if the cover shall be removed from the ironing board, the drawcord has to be released. This is accomplisehd by an override mechanism for the ratchet mechanism which, if activated, deactivates the ratchet mechanism and enables a rotation of the drum around the axis of rotation in both directions.
In order keep the mechanical elements of the ratchet mechanism and of the override mechanism always in a functional engagement, one or both of the ratchet mechanism and/or the override mechanism can be housed in the second chamber of the housing, protected against the surroundings by the housing.
As a part of such a ratchet mechanism, the drum may be equipped with a bar-shaped extension, which projects from the regarding end face of the drum in a direction parallel and coaxial to the axis of rotation, and has a cross-shaped or star-shaped cross-section.
Such a bar-shaped projection may be used as a guiding for a ratchet body with a recess in the form of a tunnel or a blind hole which fits over the bar-shaped extension of the drum in an interlocking manner in order to prevent a relative rotation between the ratchet body and the drum, although a relative displacement of the ratchet body relative to the drum is possible in the longitudinal direction of the drum.
According to a preferred embodiment, the ratchet body comprises a cylindrical section and a collar protruding over the cylindrical section in a radial direction. Such cylindrical section of the ratchet body can act as a guidance for a helical spring which can be shifted onto thecylindrical section, while the radially protruding collar can act as a stop which delimits the longitudinal movement of the helical spring relative to the ratchet body.
If the collar is situated near the end face of the ratchet body adjacent to the third plate, a helical compression spring can be stuck over the cylindrical section of the ratchet body between a flange of the drum near the second plate on the one hand and the collar of the ratchet body on the other hand. At such an arrangement, the helical compression spring urges the ratchet body in a direction against the third plate of the housing.
Such a pressing force between the end surface of the ratecht body and the third plate may induce a contemplation over providing an engagement between these elements, especially in the form of a row of saw teeth at the end surface of the ratecht body, which saw teeth can project against the third plate.
Such an embodiment may be further improved by arranging the row of saw teeth in such a way that the row extends along a circle at the periphery of the end face of the ratchet body. Upon rotation of the ratchet body, the saw teeth in such a row do not alter their position relative to a center of the end face of the ratchet body, but only their angular position around the axis of rotation.
As functional pendants to the saw teeth at the ratchet body, one or more additional saw teeth can be provided at the surface of the third plate facing towards the ratchet body. Such an arrangement enables a relative rotation between the ratchet body and the third, plate of the housing only in a direction where the inclined surfaces of the saw teeth can move relative to each other, by pressing the ratchet body away from the third plate temporarily.
The override mechanism of such ratchet mechanism primarily comprises a press button received within a circular hole of the third plate. Preferably, such a press button can be a central protrusion formed integrally with the ratchet body beyond the radially protruding collar.
As this press button extends through the third plate of the housing, it is accessible from outside and can be pressed inwardly, against the force of the helical compression spring, in order to displace the ratchet body towards the drum. In doing so, the saw teeth of the ratchet body are released from the saw teeth of the housing, and a rotation of the ratchet body and the drum as well is enabled in both directions relative to the housing.
Finally, the teaching of the present invention is that the housing is assembled from two halves which can be snapped together. Preferably, the common separation plane between the two halves of the housing extends along the axis of rotation of the drum. Then, the aligned holes of the one to third plate are separated at their maximum diameter, and the drum with ratchet body and spring can be inserted into one half of the housing before snapping the second half of the housing onto the first, whereby the rotatable mounting of the drum and ratchet body in the housing is completed.
Further features, details, advantages and effects on the basis of the invention will be seen from the following description of a preferrred embodiment of the invention as well as from the drawing. Therein:
- Fig. 1
- is a perspecitve view of a device for tensioning a cord of an ironing board cover according to the invention, consisting of a housing and a twist grip, where it can be seen that the housing of the device consists of two identical halves which are assembled with each other along a vertical symmetrical plane;
- Fig. 2
- is a front view of the device according toFig. 1, showing the exterior surface of one half of the housing of the device together with the twist grip;
- Fig. 3
- is a view onto the inside of one of the two halves of the housing before the assembly, but where the twist grip has already been inserted; and
- Fig. 4
- is a lateral view of the device according toFig. 1.
The device 1 shown in the drawing can be used to fix a cover to an ironing board, especially by tensioning a drawcord, which extends along a hem of the cover underneath the ironing board.
For this purpose, the device 1 comprises a drum 2 pivoted around an axis ofrotation 3, which is surrounded by a lateral surface 4 for winding up the drawcord and comprises a through-hole 5 for threading through the drawcord before rotating the drum 2.
For a precise orientation of the axis ofrotation 3, the drum 2 is mounted in a rotatable manner inside of ahousing 6. This housing is assembled from twohalves 7, 8, which are in contact with each other along a common contact orseparation plane 9.
As can be seen best inFig. 3, where thehousing 6 is opened. Thecomplete housing 6 consists of threeparallel plates 10, 11, 12, namely afirst plate 10, which is the lowermost one inFig. 3; asecond plate 11 in the middle ofFig. 3, and athird plate 12 at the top ofFig. 3. These threeplates 10, 11, 12 are connected to each other via alateral surface 13 of thehousing 6.
Although theseplates 10, 11, 12 as well as thelateral surface 13 are all referred to as one part in the specification, it should be noted that, for the purpose of a simple assembly of the device 1, they are all divided into two halves, each of which is a part of one of the twohousing halves 8, 9.
Furthermore, to allow a quick assembly of thehousing 6 from its twohalves 7, 8, there areprojections 14, 15 provided at theinner surfaces 16 of the twohalves 7, 8, which fit precisely together with theprojections 14, 15 of theopposite half 8, 7 as pendants. Theseprojections 14, 15 ofdifferent halves 7, 8 may be snapped together by a light pressure onto the twohousing halves 7, 8, so that ideally, thehousing 6 can be assembled without any adhesive, within a few seconds.
Thelateral surface 13 may be formed with rounded edges, which is a matter of minimizing any risk of injury.
Furthermore, allplates 10, 11, 12 have the same area and shape, and therefore, the cross-section of thehousing 6 is constant over its entire length or height, respectively.
As can be seen fromFig. 3, the interior of thehousing 6 is divided into twochambers 16, 17. Afirst chamber 16 is formed by thefirst plate 10, thesecond plate 11 and a lower part of thelateral surface 13, whereas asecond chamber 17 is encompassed by thesecond plate 11, thethird plate 13 and an upper part of thelateral surface 13. The volumes of bothchambers 16, 17 can be identical or nearly identical.
As the geometry of allplates 10, 11, 12 is rectangular, preferably with rounded corners, bothchambers 16, 17 have an elongated shape, with a horicontal length extending parallel to theseparation plane 9, while the width as well as the height of eachchamber 16, 17 is substantially shorter than the regarding length.
Bothchambers 16, 17 communicate with each other through acentral opening 19 in thesecond plate 11. Thiscentral opening 19 is algined with acentral opening 18 in thefirst plate 10 and with acentral opening 20 in thethird plate 12. In the following, thecentral opening 18 in thefirst plate 10 will be denoted asfirst opening 18, thecentral opening 19 in thesecond plate 11 will be denoted assecond opening 19, and thecentral opening 20 in thethird plate 12 will be denoted asthird opening 20. The first andsecond openings 18, 19 have a circular cross-setion, and preferably thethird opening 20, too.
Abody 21 comprising the drum 2 extends through the first andsecond openings 18, 19.
The central portion of thisbody 21 is formed by the drum 2. Preferably, the lateral surface 4 of the drum 2 is not in the form of a cylindrical casing, but it is shaped like two antiparallel conical surfaces which are connected at their tapered ends. This results in a geometry of the drum 2 with the lateral surface 4 being tapered in the middle between twoend portions 22, 23.
These twoend portions 22, 23 are in the form of flat cylindrical discs with a cylindrical perimeter, and preferably, the diameter of the drum 2 converges to the diameter of the regardingend 22, 23 and merges into the regardingcylindrical end 22, 23 without any step.
The distance between the twocylindrical end portions 22, 23 is identical to the distance between the first andsecond plate 10, 11. Furthermore, as the diameter of the twocylindrical end portions 22, 23 of thebody 21 is the same as the diameter of the first andsecond opening 18, 19, thecylindrical end portions 22, 23 can be received in the first andsecond openings 18, 29 like a shaft in friction bearings.
In order to hold thebody 21 comprising the drum 2 in place and to prevent a longitudinal displacement thereof, bothcylindrical end portions 22, 23 are delimited in the longitudinal direction between the conicallateral surface 13 of the drum on the one hand and an adjoiningflange 24, 25 with a greater diameter on the other hand.
These adjoiningflanges 24, 25 extend along the first andsecond plates 10, 11 outside of thefirst chamber 16. As the diameter of theseflanges 24, 25 is even greater than the diameter of the first andsecond openings 18, 19, they cannot slip through the first andsecond openings 18, 19, but hold the drum 2 of thebody 21 in position between the first andsecond plates 10, 11, ,that is inside of thefirst chamber 16. The only permitted movement relative to thehousing 6 of thebody 21 comprising the drum 2 is a rotation around the axis ofrotation 3.
The drum 2 is equipped with a through-hole 5 for threading through a two ends of a drawcord of a ironing board cover. This through-hole 5 has an elongated cross-section extending through the lateral surface 4 of the drum 2 between bothcylindrical end portions 22, 23. The cross-section of this through-hole 5 is rounded, as well as theedges 26 between theinner side 27 of the through-hole 5 and the lateral surface 4 of the drum 2, in order to avoid any sharp edges which could harm a drawcord threaded into the through-hole 5.
In order to enable such a threading of the ends of a drawcord into the through-hole 5, thelateral surface 13 of thehousing 6 is provided with twoholes 28, preferably elongated holes which are similar in shape to the cross-section of the through-hole 5, and whih are aligned with the through-hole 5, if thebody 21 is in an angular position where the orientation of a line traversing the drum 2 along the through-hole 5 is perpendicular to thelateral surface 13 of the housing adjacent to the drum 2.
So, in such an angular position of thebody 21, the ends of a drawcord can be threaded directly through thehousing 6 from one side to the other side, and accurate through the through-hole 6 in the drum 2. In order to find this angular position easily, theend portion 22 near thefirst plate 10 is equipped with atwist grip 29.
Thetwist grip 29 comprises abase plate 30 which is parallel to thefirst plate 10 and has the same size and shape as thefirst plate 10, especially a rectangular shape wis rounded corners, and further agrip plate 31 projecting perpendicularly from thebase plate 30 outwards along a linkingline 32. Thegrip plate 31 is used as the actual grip and may be grasped between two fingers or between the thumb and the forefinger.
Thetwist grip 29 is formed integrally with thebody 21 or is fixed thereto in a torque-proof manner, in a position where the orientation of a line traversing the drum 2 along the through-hole 5 is perpendicular to thegrip plate 31. Therefore, in a relative position, where the linkingline 32 is aligned with theseparation plane 9 of thehousing 6, the through-hole 5 is aligned with theholes 29 in thehousing 6, and a drawcord can be threaded entirely through thehousing 6 of the device 1.
After feeding the drawcord through the device 1 in this manner, thegrip 29 can be twisted in order to rotate the drum 2 and to wind the drawcord onto the lateral surface 4 of the drum 2. A further mechanism is required to lock an angular position of the drum 2 after the ends of the drawcord have been wound around the drum 2 and the drawcord has been tensioned in this way. This mechanism is aratchet mechanism 33 which is arranged in thesecond chamber 17 of thehousing 6.
One element of theratchet mechanism 33 is a protrusion or bar-shapedextension 34 of thebody 21 which extends beyond thesecond flange 25 and is parallel to the longitudinal axis or axis ofrotation 3 of the drum 2. This bar-shapedextension 34 has a cross-shaped or star-shaped cross-section and is used as a guidance for aratchet body 35.
Theratchet body 35 is provided with a recess in the form of a tunnel or a blind hole which fits over the bar-shaped extension of the drum. The cross-section of the recess in theratchet body 35 is identical or similar to the cross-section of the bar-shapedextension 34. Therefore, theratchet body 35 is permitted to slide along the bar-shapedextension 34, but cannot twist relative to thedrum body 21.
Furthermore, theratchet body 35 comprises acylindrical portion 36 facing thesecond flange 25 of thedrum body 21, and a collar 37 extending radially outwards from thecylindrical portion 36 near thethird plate 12 of thehousing 6.
Ahelical compression spring 38 is stuck over thecylindrical portion 36 of theratchet body 35, especially between the regardingflange 25 of thedrum body 21 near thesecond plate 11 on the one hand and the collar 37 of theratchet body 35 on the other hand and urges theratchet body 35 apart from thedrum body 21.
The collar 37 is provided at its end face facing away from thedrum body 21 with a row ofsaw teeth 39. This row extends completely around the collar's circumference of the collar 37, and all sawteeth 39 have the same shape and are lined up along the row in the same direction.
One ormore saw teeth 40 are provided at the inner side of thethird plate 12 as pendants to thesaw teeth 39 in the row at theratchet body 35. Therefore, if thetwist grip 29 is rotated in a direction where theinclined edges 41 of thesaw teeth 39, 40 are shifted over each other, thedrum body 21 can be rotated, beause theratchet body 35 is urged by thesaw teeth 39, 40 towards thesecond plate 11. In the other direction, thevertical edges 42 of the saw teeth prevent any rotation of thedrum body 21.
On the other hand, a release mechanism is necessary in case the drawcord shall be released. This is achieved by an
override mechanism 43 which is realized by an
elevated press button 44 at the center of the end face of the collar 37 facing away from the
cylindrical portion 36. This
press button 44 has a diameter equal to or smaller than the
third opening 20 in the
thrid plate 12, and protrudes through this
opening 20 to the outside of the
housing 6. If this
press button 44 is pressed, the
ratchet body 35 is urged towards the drum 2 and the
saw teeth 39 of the
ratchet body 35 are freed from the
saw teeth 40 at the
third plate 12, thereby allowing a rotation of the
ratchet body 35 in any direction. This degree of freedom is transferred onto the
drum body 21 which is allowed to rotate in both directions, too.
Reference numerals| 1 | device | 26 | edge |
| 2 | drum | 27 | inner side |
| 3 | axis ofrotation | 28 | hole |
| 4 | lateral surface | 29 | twist grip |
| 5 | through-hole | 30 | base plate |
| 6 | housing | 31 | grip plate |
| 7 | half | 32 | linkingline |
| 8 | half | 33 | ratchet mechanism |
| 9 | separation plane | 34 | bar-shapedextension |
| 10 | first plate | 35 | ratchet body |
| 11 | second plate | 36 | cylindrical portion |
| 12 | third plate | 37 | collar |
| 13 | lateral surface | 38 | helical compression spring |
| 14 | projection | 39 | sawtooth |
| 15 | projection | 40 | sawtooth |
| 16 | first chamber | 41 | inclined edge |
| 17 | second chamber | 42 | vertical edge |
| 18 | first opening | 43 | override mechanism |
| 19 | second opening | 44 | press button |
| 20 | third opening | | |
| 21 | drum body | | |
| 22 | cylindrical end portion | | |
| 23 | cylindrical end portion | | |
| 24 | flange | | |
| 25 | flange | | |