EP2943095B1

EP2943095B1 - Upholstery spindle

Info

Publication number: EP2943095B1
Application number: EP14706133.7A
Authority: EP
Inventors: Aleksander Borgenhov; Sigmund ØVERENG
Original assignee: Scandinavian Business Seating AS
Current assignee: Scandinavian Business Seating AS
Priority date: 2013-01-10
Filing date: 2014-01-08
Publication date: 2018-03-21
Anticipated expiration: 2034-01-08
Also published as: CN105007781B; NO339352B1; WO2014109646A1; EP2943095A1; CN105007781A; NO20130056A1

Description

Technical field

The present invention relates to devices and methods of fastening upholstery to furniture. More specifically, the present invention relates to devices comprising a circumferential draw string and a means for locking the drawstring in place once tightened.

Background

References considered to be relevant as background art useful to understand the invention are cited below:

Furniture may have a frame and one or more portions covered with a sheet material, such as fabric or leather. The sheet material can be provided for decorative purposes or as a seating surface. Sometimes, padding is provided behind the sheet material, for improving seating comfort, and for keeping the sheet material stretched.
The padding is often elastic foam, such as latex or polyethylene.
In order to fit the sheet material to the piece of furniture, the sheet material is stretched around the padding, and fixed to the furniture using staples or nails forced into a frame member of the piece of furniture.
After some use of the furniture, the sheet material may become worn, or lose its form, such that it is necessary to replace it or stretch it. A drawback with the use of nails or staples is that it is time consuming to attach and to detach the sheet material. Sometimes, furniture members, such as seat and arm rest for office chairs, are provided with sheet material provided with a circumferential guiding channel through which a string is led, wherein the sheet material can be cinched around the seat or arm rest by tensioning the string.
Special tensioning tools are used to control the tensioning of the string.
Once tensioned, the string is kept from losing its tension, by means of a clamp device clamping the string to the arm rest or seat. The clamp device may be a self threading screw with a large head or washer pressing the string against a portion of the furniture member. Alternatively, the string self intersects and is fixed by means of a knot. Should the sheet material need re-tensioning or replacement, it may be made by releasing the clamping means, adjusting the tension of the string, and subsequently locking the clamping means.
A drawback of using such clamping means is that special tensioning tools are typically needed, for keeping the string properly tensioned during locking of the clamping means. Such special tools are not commonly available. Also, a drawback of clamping means comprising a self-threading screw, is that the screw hole is worn upon tensioning and loosening the screw. Also, it is difficult and requires skill to properly position and tension the sheet material, whilst tensioning the string.

Summary

It is an object of the present invention to mitigate the above mentioned disadvantages. According to the invention, there is provided an upholstery tensioning system as defined in appended independent claim 1. In order to attach a piece of sheet material to the piece of furniture, a string is routed along the circumference of the piece of sheet material, for example through eyelets, or in a channel, provided along the circumference of the piece of sheet material. The piece of sheet material is then wrapped around the piece of furniture. The string is attached to the spindle and the spindle is rotated by means of hand power and/or standard tools such as pliers or wrench, to tension and wind-up the string. The standard tool, such as a socket wrench, may be attached to an electric driving means, such as an electric screwdriver, to speed up rotation. Since both ends of the string are wound up around the spindle during tensioning, the string is normally not visible during standard use of the furniture. This also means no further compartments and operations are needed to confine free string ends after tensioning of the string, thereby saving production time and cost. The string may be attached to the spindle by winding it around the spindle such that friction keeps it from sliding relative to the spindle. Once the string is properly tensioned, the spindle is prevented from rotating by engagement of the locking means. If the piece of flexible sheet material needs adjustment or replacement, the locking means is temporarily released and the spindle rotated to control the tension of the string.
The upholstery tensioning system thus enables tensioning of the string without use of special tools. Further, the system is not prone to wearing. Also, operation of the system is easy and requires no special skill.
The locking means comprise a ratchet device. The ratchet device makes the locking means self-locking, yet easily releasable. The ratchet device comprises pawls provided on the circumference of the spindle, and matching teeth provided on the furniture member. The pawls extending from the spindle are biased against the teeth of the furniture member, to slide over the teeth during rotation of the spindle in one direction, and to grip the teeth at rotation in the opposite direction to thereby prevent further rotation in said opposite direction.
The pawls may be integrally formed with the spindle. Integrating the pawls with the spindle reduces the number of parts needed, and provides a more robust design.
The pawls may be distributed around the spindle such as to provide for balanced movement of the spindle around its rotational center. The pawl is thereby easy to install by simply pushing it in place whilst rotating it. Further, there is no need for a central axial connection between spindle and support means for controlling rotation of the spindle. Specifically, the pawls may be evenly distributed around the rotational center of the spindle. Thus, the resultant forces of the pawls biased against the surrounding recess substantially cancels each other out.
The spindle may be provided with string locking means. By locking a portion of the string with the locking means, it is possible to wind up string without the string slipping relative to the spindle and without relying solely on friction between string and spindle. The locking means may comprise a recess provided in a top flange of the spindle, said flange extending radially outwards from a core of the spindle. Since the recess extends radially outwards, the string cannot be pulled out of the recess by tensioning of the string around the core of the spindle.
The spindle may be provided with gripping means for engagement with a standard tool, such as screw driver, wrench or hex key. The gripping means may form a hex-head. The provision of gripping means for interaction with standard tools makes it easy to grip the spindle for rotation, and minimizes risk of slipping, damage and wear of the spindle. An aspect of the invention relates to a piece of furniture comprising an upholstery tensioning system according to the invention. Production and service of such furniture is made much easier because of the provision of the inventive system. A further invention relates to a method of tensioning upholstery on a furniture member, comprising the steps of: cinchably attaching a string to the upholstery material to be tensioned, attaching the string to a spindle rotatably supported on the furniture member and suitable for receiving and winding up string, rotating the spindle to wind up string and thereby cinch and tension the upholstery, and locking the spindle to prevent it from rotating. Such tensioning of upholstery is very efficient and may be performed by one person, since that person can focus on rotating the spindle and fixing only the spindle, and not a plurality of staples and screws. The present inventions will now be described in more detail, with reference to the appended drawings showing a non-limiting embodiment of the invention.

Description of figures

Fig. 1 shows a perspective view of an upholstery tensioning system according to an embodiment of the invention.
Fig. 2 shows a top view of the system also shown in Fig. 1.
Fig. 3 shows a side view of a spindle being part of the system also shown in Figs. 1-2.
Fig. 4 shows a top view of the spindle also shown in Fig. 3.

Detailed description

As shown in Figs. 1-4, an upholstery tensioning system according to an embodiment of the invention comprises a spindle 1 suitable for receiving and winding up string 2. The spindle 1 is attached to a furniture member 3 by a support means 4 comprising a central axis 5 and a circular recess at its circumference provided with teeth 10. A top portion of the central axis 5 is provided with a plurality of snap locking tongues, configured to enable the spindle 1 to be brought onto the central axis 5, into the recess, and snap locked in place. The snap-lock thus allows the spindle 1 to be fitted upside-down without falling off the furniture member 3.
The spindle 1 is provided with three pawls 6, 7, 8 evenly distributed around the rotational axis 9 of the spindle 1. In use, the pawls 6, 7, 8 are biased against the teeth 10 of the support means 4 at rotation of the spindle 1, so as to ratchedly engage with the teeth 10 and thereby allow rotation of the spindle 1 in one direction, whilst preventing rotation of the spindle 1 in the opposite direction.
The pawls 6, 7, 8 are integrally formed with the spindle 1 by injection molding of the spindle. Preferably, the spindle 1 is made of a fiberglass-reinforced plastic. As shown in Fig. 4, each pawl 6, 7, 8 comprises a rigid base portion 11 and a tongue 12 extending from the base portion 11. The pawls 6, 7, 8 are designed to fit into the recess of the support means 4 with the pawls 6, 7, 8 aligned with the teeth 10 as shown in Fig. 2. Thus, this design of the spindle 1 allows the spindle 1 to be fitted without bending or moving the pawls 6, 7, 8, and hence provides for easy installation. However, in order to allow rotation of the spindle 6, 7, 8, the tongues 12 move to make room for the teeth 10 to pass. This design of the pawls 6, 7, 8, with a flexible tongue, enables the tongue to move during rotation of the spindle 1 in one direction.
A front portion 13 of each respective base 11 portion is radially inwardly inclined, such that a lead-in portion is created on each pawl 6, 7, 8. The lead-in portions lead the teeth 10 onto the pawls 6, 7, 8 at rotation of the spindle 1. This provides for smooth movement of the spindle 1 at rotation, and enables the tongues 12 to gradually bend and move.
As shown in Fig. 2 string 2 is routed in a channel of the upholstery to be tensioned, to form a loop. A routing pin 14 is provided on the furniture member 4 to enable controlled redirection of the string 2 from the loop to the spindle 1.
The spindle 1 comprises a core 15, a top flange 16, and a bottom flange 17. The top flange 16 is hex-shaped to enable convenient rotation of the spindle by means of a commonly available tool, such as pliers or wrench. The top flange 16 is provided with two opposite recesses 18, 19 extending radially outwards from the core 15. The recesses 18, 19 are adapted to receive and lockingly engage with string 2 to be wound onto the core 15. The core 15 is provided with a central cylindrical recess 20 for receiving the central axis 5 of the support means 4. A top portion of the cylindrical recess 20 is provided with a further circumferential recess or shelf 21 configured to receive protrusions of the snap locking tongues of the central axis 5.

Claims

An upholstery tensioning system comprising a furniture member (3), a spindle (1) suitable for receiving and winding up string (2), locking means configured to optionally prevent the spindle (1) from rotating relative to the furniture member (3), and a ratchet device configured to prevent rotation of the spindle (1) in one direction, wherein the ratchet device comprises pawls (6, 7, 8) provided on the circumference of the spindle (1), and matching teeth (10) provided on the furniture member (3), wherein the furniture member (3) is provided with support means (4) configured to rotatably support the spindle (1) on the furniture member (3), characterized in that each pawl (6,7,8) comprises a rigid base portion (11) and a flexible tongue (12) extending from the base portion (11), and the pawls (6,7,8) are designed to fit into a recess of the support means (4) with the pawls (6,7,8) aligned with the teeth (10).
An upholstery tensioning system according to claim 1, wherein the pawls (6, 7, 8) are integrally formed with the spindle (1).
An upholstery tensioning system according to any one of the preceding claims, wherein the pawls (6, 7, 8) are distributed around the spindle (1) such as to provide for balanced movement of the spindle (1) around its rotational center.
An upholstery tensioning system according to any one of the preceding claims, wherein the pawls (6, 7, 8) are evenly distributed around the rotational center of the spindle (1).
An upholstery tensioning system according to any one of the preceding claims, wherein the spindle (1) is made of a fiberglass-reinforced plastic.
An upholstery tensioning system according to any one of the preceding claims, wherein the spindle (1) is provided with string locking means.
An upholstery tensioning system according to claim 6, wherein the spindle (1) comprises a recess provided in a top flange of the spindle (1), said flange extending radially outwards from a core of the spindle (1).
An upholstery tensioning system according to any one of the preceding claims, wherein the spindle (1) may be provided with gripping means for engagement with a standard tool, such as screwdriver, wrench or hex key.
A piece of furniture comprising an upholstery tensioning system according to any one of the preceding claims.
A method of tensioning upholstery on a furniture member, comprising the steps of: cinchably attaching a string (2) to the upholstery material to be tensioned, attaching the string (2) to a spindle (1) rotatably supported on the furniture member (3) and suitable for receiving and winding up string (2), rotating the spindle (1) to wind up string (2) and thereby cinch and tension the upholstery, and locking the spindle (1) to prevent it from rotating.