Apparatus and method for control of spring force in a door closer or operator
View Patent ↗An apparatus for adjusting the force in a door operator or closer comprises an elongated housing and a spring therein connected to the door operator or closer. A spring collar is non-rotatable about the longitudinal axis of the housing and adapted to move linearly within the housing. A fixed adjusting screw extends along a longitudinal axis of the housing and the spring collar is slidable linearly along an outer surface of the adjusting screw. A nut is threadably engaged at a distal end of the adjusting screw and is rotatable about the longitudinal axis of the screw, the nut bearing on the spring collar during rotation. The spring collar bears on a distal end of the spring to vary the spring compression and thereby vary force applied by the door operator or closer. The housing has an opening in a sidewall through which the spring is visible, and the housing exterior surface includes markings indicating the degree of spring compression. An indicator is moveable along and visible from the exterior of the housing to indicate the compression of the spring.
1. An apparatus for adjusting the force in a door operator or closer for closing a door, comprising:
a housing having a longitudinal axis;
a spring within the housing and connected to the door operator or closer, the spring being compressible to different positions to vary force applied by the door operator or closer;
a spring collar non-rotatable about the longitudinal axis of the housing and slideable linearly within the housing, the spring collar bearing on the spring to vary the spring compression and thereby vary force applied by the door operator or closer;
an adjusting screw extending along the longitudinal axis of the housing and passing through the spring collar; and
a nut threadably engaged at an end of the adjusting screw distal from the door operator or closer and rotatable about the longitudinal axis, the nut bearing on the spring collar during rotation,
wherein the spring collar prevents rotation of the adjusting screw about the longitudinal axis of the housing.
2. The apparatus of claim 1 wherein the housing is a tube coaxially disposed about the longitudinal axis.
3. The apparatus of claim 1 wherein the spring has an end distal from the door operator or closer, and the spring collar bears against the spring end.
4. The apparatus of claim 1 wherein the adjusting screw does not turn upon rotation of the nut.
5. The apparatus of claim 1 further including an end cap at a distal end of the housing, the end cap comprising an opening permitting access for rotation of the nut.
6. The apparatus of claim 1 wherein the spring is a coil spring and the adjusting screw extends through the coil spring.
7. The apparatus of claim 1 wherein the spring collar is slidable linearly along an outer surface of the adjusting screw.
8. The apparatus of claim 7 wherein the outer surface of the adjusting screw comprises opposing flat sections and the spring collar comprises an opening having flat interior sides for mating with the adjusting screw flat sections.
9. The apparatus of claim 1 wherein the housing includes a sidewall having a slot extending along at least a portion of a length thereof and the spring collar includes a tab received within and slidable in the housing slot, the tab preventing rotation of the spring collar about the longitudinal axis of the housing.
10. The apparatus of claim 9 wherein the spring collar tab is at least partially visible from the exterior of the housing through the sidewall slot to indicate compression of the spring.
11. The apparatus of claim 1 wherein the housing includes a sidewall having an opening, and wherein a position of the spring and at least a portion of the spring collar is viewable from the exterior of the housing through the sidewall opening.
12. The apparatus of claim 11 further including one or more markings on the housing indicating the degree of spring compression.
13. The apparatus of claim 11 further including an indicator moveable along and visible outside the housing to indicate the compression of the spring.
14. The apparatus of claim 1 wherein the spring collar and housing have complementary-shaped non-circular cross-sections to prohibit rotation of the spring collar about the longitudinal axis of the housing while permitting linear movement of the spring collar within the housing.
15. The apparatus of claim 14 wherein the spring collar comprises a plurality of spaced protrusions about its perimeter and an interior surface of the housing comprises a plurality of spaced depressions which mate with the spring collar protrusions.
16. A method of adjusting the force in a door operator or closer for closing a door comprising:
providing a housing having a longitudinal axis; a spring within the housing and connected to the door operator or closer; and a spring collar non-rotatable about the longitudinal axis of the housing and slideable linearly within the housing, the spring collar bearing on the spring and being adjustable by sliding the spring collar linearly along the longitudinal axis of the housing; an adjusting screw extending along a longitudinal axis of the housing and passing through the spring collar; and a nut threadably enagaged at an end of the adujusting screw distal from the door operator or closer and rotatable about the longitudinal axis, the nut bearing on the spring collar during rotation; and
sliding the spring collar linearly along the longitudinal axis of the housing to vary compression of the spring by rotating the nut about a longitudinal axis of the adjusting screw, thereby varying force applied by the door operator or closer to close the door,
wherein the spring collar prevents rotation of the adjusting screw about the longitudinal axis of the housing.
17. The method of claim 16 wherein the nut is rotated clockwise or counterclockwise to increase or decrease the spring compression and the force applied by the door operator or closer.
18. The method of claim 16 wherein the housing includes a sidewall having an opening, a position of the spring being viewable from the exterior of the housing through the sidewall opening, and further including:
viewing the position of the spring from the exterior of the housing through the sidewall opening.
19. The method of claim 16 wherein the housing includes a sidewall having a slot extending along at least a portion of a length thereof and the spring collar includes a tab received within and slidable in the housing slot, the tab being at least partially visible from the exterior of the housing through the sidewall opening to indicate compression of the spring, and further including:
viewing the position of the spring collar tab from the exterior of the housing through the sidewall opening to determine the position of the spring and the force applied by the spring to the door operator or closer.
20. The method of claim 16 wherein the spring collar is slidable along an outer surface of the adjusting screw, and wherein the step of moving the spring collar linearly along the longitudinal axis of the housing comprises:
rotating the nut about the longitudinal axis of the adjusting screw to cause the spring collar to slide along the outer surface of the adjusting screw to a desired position to apply the desired force to the door operator or closer.
21. The method of claim 16 wherein the housing includes an end cap at a distal end of the housing comprising an opening permitting access for rotation of the nut, and wherein the step of moving the spring collar linearly along the longitudinal axis of the housing comprises accessing the nut through the end cap opening and rotating the nut about the longitudinal axis of the adjusting screw while the housing remains stationary.