Roller shade with a pretensioned spring and method for pretensioning the spring

Patent metadata

Field	Value
Publication number	US-9631425-B2
Application number	US-201514847506-A
Country	US
Kind code	B2
Filing date	Sep 8, 2015
Priority date	Sep 8, 2015
Publication date	Apr 25, 2017
Grant date	Apr 25, 2017

Abstract

A roller shade is disclosed having a counterbalancing assembly with an optimally pretensioned spring that lowers the torque load on the motor of the roller shade throughout the rolling up or rolling down cycles. The roller shade comprises a roller tube, a gudgeon pin having a first stop, a gudgeon body having a through bore and rotatably connected about the gudgeon pin and operably connected to the roller tube, a limit nut operably connected to the gudgeon body and adapted to axially travel along the gudgeon pin within the through bore, a spring, a first spring carrier connected to the first end of the spring and operably connected to the gudgeon pin, and a second spring carrier connected to the second end of the spring and operably connected to the roller tube. The spring is pretensioned and the limit nut abuts the first stop thereby locking the pretension. Rotation of the roller tube to roll down the shade further tensions the spring, and rotation of the roller tube to roll up the shade releases the tension in the spring.

First claim

The invention claimed is:

1. A roller shade comprising:
a roller tube;
a gudgeon pin comprising a first stop and a second stop;
a gudgeon body rotatably connected about the gudgeon pin and operably connected to the roller tube, wherein the gudgeon body comprises a through bore;
a limit nut operably connected to the gudgeon body and adapted to axially travel along the gudgeon pin, within the through bore and between the first stop and the second stop;
a pretensioned spring comprising a first end and a second end and the spring longitudinally extending therebetween, wherein the limit nut abuts the first stop or the second stop thereby locking pretension in the pretensioned spring;
a first spring carrier connected to the first end of the spring and operably connected to the gudgeon pin; and
a second spring carrier connected to the second end of the spring and operably connected to the roller tube;
wherein during pretensioning of the pretensioned spring, the roller shade comprises:
the second spring carrier positioned within the roller tube such that the second spring carrier is operably connected to the roller tube;
the gudgeon body positioned outside the roller tube;
the gudgeon body rotating with respect to the roller tube, thereby causing the limit nut to rotate and axially travel in a first direction, until the limit nut comes in contact with the first stop or the second stop;
after the limit nut comes in contact with the first stop or the second stop, the gudgeon body further rotating with respect to the roller tube a predetermined number of pretension turns, thereby causing the first spring carrier and the first end of the spring to rotate with respect to the second spring carrier and the second end of the spring; and
the gudgeon body inserted inside the roller tube thereby locking the pretension.

2. The roller shade of claim 1 , wherein rotation of the roller tube to roll down the roller shade causes rotation of the second end of the spring in a first direction with respect to the first end of the spring, thereby tensioning the spring.

3. The roller shade of claim 2 , wherein rotation of the roller tube to roll up the roller shade causes rotation of the second end of the spring in a second direction, opposite to the first direction, with respect to the first end of the spring, thereby releasing the tension in the spring.

4. The roller shade of claim 1 , wherein the pretensioned spring comprises a predetermined number of pretension turns N p determined according to the following formula:

N
p

=

T
min_offset

k

where,
T min _ offset is substantially equal to, or offset by a predetermined amount from, a minimum amount of torque required to finish rolling up the roller shade, and
k is substantially equal to a torque slope of the roller shade.

5. The roller shade of claim 4 , wherein the torque slope k of the roller shade is determined according to the following formula:

k
=

T
max

-

T
min

N
t

where
T max is substantially equal to a maximum amount of torque required to start rolling up the roller shade,
T min is substantially equal to the minimum amount of torque required to finish rolling up the roller shade, and
N t is a number of turns it takes to fully roll up the roller shade.

6. The roller shade of claim 5 , wherein T max and T min are determined according to the following formulas:
T max =r rt ×( w sm +w hb ) T min =r sm ×w hb

where
r rt is a radius of the roller tube,
w sm is a weight of a shade material,
w hb is a weight of a hem bar, and
r sm is a radius of the shade material when it is fully wrapped around the roller tube.

7. The roller shade of claim 1 , wherein the gudgeon pin comprises a proximal portion, a middle portion, and a distal portion, wherein the first stop is disposed between the proximal portion and the middle portion, and wherein the second stop is disposed between the middle portion and the distal portion.

8. The roller shade of claim 1 , wherein the gudgeon body is rotatably connected about the gudgeon pin via at least one ball bearing.

9. The roller shade of claim 8 , wherein the gudgeon body comprises at least one ball bearing cavity dimensioned to receive the at least one ball bearing therein.

10. The roller shade of claim 1 further comprising a spring mandrel connected to the gudgeon pin, wherein the spring is mounted about the spring mandrel.

11. The roller shade of claim 1 , wherein the gudgeon body comprises a wheel with an external surface that contacts an inner surface of the roller tube.

12. The roller shade of claim 1 , wherein the gudgeon body comprises a flange radially extending therefrom that prevents the gudgeon body from sliding entirely into the roller tube.

13. The roller shade of claim 1 , wherein the gudgeon body further comprises a plurality of teeth extending circumferentially about an external surface of the gudgeon body that form a friction fit between the external surface of the gudgeon body and an inner surface of the roller tube.

14. The roller shade of claim 1 , wherein the gudgeon body further comprises a plurality of channels extending circumferentially about an external surface of the gudgeon body that mate with complementary projections radially extending from an inner surface of the roller tube.

15. The roller shade of claim 1 , wherein the gudgeon pin comprises a gudgeon pin tip disposed on a terminal end of the gudgeon pin that attaches to a mounting bracket.

16. The roller shade of claim 1 , wherein at least one of the first stop and the second stop comprises at least one of a ring, a pin, a screw, or any combination thereof.

17. The roller shade of claim 1 , wherein the gudgeon pin and the limit nut are threaded and wherein the limit nut is threadably connected to the gudgeon pin.

18. The roller shade of claim 1 , wherein the through bore comprises a cross-section having a shape that complements and mates with a shape of the limit nut.

19. The roller shade of claim 18 , wherein the limit nut and the cross-section of the through bore comprise the shape selected from the group consisting of a hexagon, a triangle, a square, a heptagon, an octagon, and a star.

20. The roller shade of claim 1 , wherein the gudgeon pin travels axially within the through bore and wherein the first stop and the second stop limit the axial travel of the gudgeon pin with respect to the gudgeon body.

21. The roller shade of claim 1 , wherein the second spring carrier comprises a wheel with an external surface that contacts an inner surface of the roller tube.

22. The roller shade of claim 21 , wherein the wheel of the second spring carrier is dimensioned such that it is operably connected to the roller tube and c

Assignees

• Crestron Electronics Inc

Inventors

• Campagna Michael

Classifications

• E06B9/72

  comprising an electric motor positioned inside the roller · CPC title

• E06B9/60 Primary

  Spring drums operated only by closure members · CPC title

• F16C11/04

  Pivotal connections (hinges for doors, windows or wings E05D) · CPC title

• E06B9/44

  Rollers therefor; Fastening roller blinds to rollers · CPC title