Awning extension and retraction mechanism

Information

  • Patent Grant
  • 6276424
  • Patent Number
    6,276,424
  • Date Filed
    Tuesday, March 7, 2000
    24 years ago
  • Date Issued
    Tuesday, August 21, 2001
    23 years ago
Abstract
An awning includes a roller assembly having a torsion spring, a canopy connected between a wall the roller assembly, and a pair of “four-bar” arm assemblies supporting opposite ends of the roller assembly. The arm assemblies move the roller assembly between a retracted position and an extended position, where the torsion spring biases the roller assembly toward the retracted position. Each arm assembly includes a vertically extending base arm secured to the wall, a bottom arm having a first end pivotally connected to the base arm, an extended arm having a first end pivotally connected to the bottom arm and a second end supporting the roller assembly, and a top arm having a first end pivotally connected to the base arm and a second end pivotally connected to the extended arm. Each arm assembly also includes a force producing member extending between the base arm and the bottom or top arm to move the arm assembly toward the extended position. The force producing member may be an electric linear actuator extending between the base arm and the bottom arm. A counter-balance spring biases the arm assembly toward the extended position to counter-balance the torsion spring.
Description




BACKGROUND OF THE INVENTION




The present invention generally relates to retractable awnings of the type to be mounted to a substantially vertical support surface and, more specifically, to such awnings which have powered automatic operation or assisted manual operation.




There are a number of known retractable awnings that support an awning or canopy to create a sheltered area. An inner end of the canopy is typically secured to a wall and an outer end of the canopy is typically secured to a roller assembly. The roller assembly is supported at its ends by support arms for movement between a retracted position, wherein the roller assembly is disposed adjacent the wall, and an extended position, wherein the roller assembly is extended out away from the wall. When the roller assembly is in the retracted position, the canopy is rolled-up on the roller assembly. When the roller assembly is in the extended position, the canopy is unrolled from the roller assembly and extends between the wall and the roller assembly. These retractable awnings are often designed for use with movable support structures such as, for example, recreational vehicles, travel trailers, mobile homes, and the like, but are also usable with fixed structures.




While these prior awning assemblies may adequately perform their intended functions, they are often difficult to deploy and retract due to their heavy weight, complex operation and numerous operational steps, particularly for elderly and physically challenged individuals. To overcome this problem, automatic awnings and assisted manual awnings have been developed. See U.S. Pat. Nos. 5,597,006 and 4,160,458, and 3,847,171, for example, each disclosing powered mechanisms for automatically operating a retractable awning. See U.S. Pat. No. 5,148,848, for example, disclosing a spring-assist mechanism for a retractable awning. While these mechanisms may some what improve operation, each is still relatively difficult to operate, is difficult and expensive to manufacture or repair, and/or is unreliable in the field. Accordingly, there is a need in the art for an improved retractable awning which has powered automatic operation or assisted manual operation.




BRIEF SUMMARY OF THE INVENTION




The present invention provides a retractable awning which overcomes at least some of the above-noted problems of the related art. According to the present invention, the awning includes a roller assembly with a torsion spring, a flexible canopy having an inner edge for connection to a wall and an outer edge secured to the roller assembly, and a pair of arm assemblies supporting opposite ends of the roller assembly. The arm assemblies are operable to move the roller assembly between a retracted position adjacent the wall and an extended position spaced from the wall. The torsion spring of the roller assembly biases the roller assembly toward the retracted position. Each arm assembly includes a vertically extending base arm for connection to the wall, a bottom arm having a first end pivotally connected to the base arm, an extended arm having a first end pivotally connected to the bottom arm and a second end connected to and supporting the roller assembly, and a top arm having a first end pivotally connected to the base arm above the bottom arm and a second end pivotally connected to the extended arm. Each arm assembly also includes a powered actuator extending between the base arm and the bottom arm for pivoting the bottom arm to move the roller assembly between the retracted position and the extended position.




According to a first preferred embodiment of the present invention, the powered actuator provides a force for moving the roller assembly to the extended position and an oppositely-directed force for moving the roller assembly to the retracted position. The powered actuator is preferably an electric linear actuator.




According to a second preferred embodiment of the present invention, the extended arm has a pair of side walls extending from opposing side edges of a main wall to define a channel that at least partially receives the bottom arm when the roller assembly is in the retracted position.




According to a third preferred embodiment of the present invention, the base arm has a pair of side walls extending from opposing side edges of a main wall to form a channel. The top arm is at least partially received in the channel when the roller assembly is in the retracted position.











BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING




These and further features of the present invention will be apparent with reference to the following description and drawings, wherein:





FIG. 1

is a side elevational view of a powered automatic awning according to the present invention in a stored or retracted position;





FIG. 1A

is an enlarged cross-sectional view taken along line


1


A—


1


A of

FIG. 1

;





FIG. 2

is a side elevational view of the awning of

FIG. 1

in a partially deployed or extended position;





FIG. 3

is a side elevational view of the awning of

FIGS. 1 and 2

in a fully deployed or extended position;





FIG. 3A

is an enlarged cross-sectional view taken along line


3


A—


3


A of

FIG. 3

;





FIG. 3B

is an enlarged cross-sectional view taken along line


3


B—


3


B of

FIG. 3

;





FIG. 4

is an enlarged and fragmented elevational view, partially in cross-section, showing the end of a roller assembly of the awning assembly of

FIG. 1

;





FIG. 5

is an enlarged perspective view of an automatic arm assembly of the awning assembly of

FIGS. 1

to


3


in the fully extended position;





FIG. 6

is an exploded view of the arm assembly of

FIG. 5

;





FIG. 7

is an enlarged and fragmented side elevational view, partially in cross section, showing a counter-balance spring of the awning assembly of

FIG. 1

;





FIG. 8

is an enlarged perspective view of the counter-balance spring of

FIG. 7

;





FIG. 9

is a side elevational view similar to

FIG. 7

but showing an alternative counter-balance spring;





FIG. 10

is an enlarged perspective view of the counter-balance spring of

FIG. 9

;





FIG. 11

is a side elevational view of a spring-assisted manual awning according to the present invention in a stored or retracted position and having a coil tension spring;





FIG. 12

is a side elevational view of the awning of

FIG. 11

in a partially deployed or extended position;





FIG. 13

is a side elevational view of the awning of

FIGS. 11 and 12

in a fully deployed or extended position;





FIG. 14

is an enlarged perspective view of a spring-assisted arm assembly of the awning assembly of

FIGS. 11

to


13


in the fully extended position;





FIG. 14A

is a fragmented view showing a variant of the spring-assisted arm assembly of

FIG. 14

;





FIG. 15

is a side elevational view of another spring-assisted manual awning according to the present invention in a stored or retracted position and having a gas compression spring;





FIG. 16

is a side elevational view of the awning of

FIG. 15

in a partially deployed or extended position;





FIG. 17

is a side elevational view of the awning of

FIGS. 15 and 16

in a fully deployed or extended position;





FIG. 18

is an enlarged perspective view of a spring-assisted arm assembly of the awning assembly of

FIGS. 15

to


17


in the fully extended position;





FIG. 19

is an enlarged elevational view of the upper end of a base arm of the awning of

FIG. 3

;





FIG. 20

is an enlarged elevational view of the lower end of the base arm of the awning of

FIG. 3

;





FIG. 20A

is an enlarged cross-sectional view taken along line


20


A—


20


A of

FIG. 20

;





FIG. 21

is a front perspective view of the lower end of the base arm; and





FIG. 22

is a rear perspective view of the lower end of the base arm.











DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS





FIGS. 1

to


3


illustrate a first embodiment of a retractable awning


10


according to the present invention. The awning


10


is a powered automatic awning which is attached to a vertically-extending support wall


12


such as a side of a recreational vehicle. The term “recreational vehicle”, as used in the specification and claims, includes campers, travel trailers, mobile homes, vans, buses, and the like. While the awning


10


is particularly advantageous when attached to recreational vehicles, it can alternatively be attached to other vertically-extending walls such as, for example, the side of a building at a patio or deck or any other transportable or fixed structure.




The awning


10


is automatically operable between a retracted or stored position (shown in

FIG. 1

) and an extended or sheltering position (shown in FIG.


3


). In the retracted position, the awning


10


is in a compact configuration close to the side support wall


12


of the recreational vehicle so that the recreational vehicle can travel to desired destinations with minimum side projections (best shown in FIG.


1


A). After a destination is reached, the awning


10


is deployed from the retracted position to the extended position if a covered area is desired to protect against sun, rain, and the like.




The awning


10


includes an awning or canopy


14


for selectively covering an area adjacent to the wall


12


, a roller assembly


16


for furling an unfurling the canopy


14


, and right and left arm assemblies


18


for supporting opposite ends of the roller assembly


16


.




The canopy


14


is a sheet of flexible material such as, for example, fabric, canvas, acrylic, or nylon and is preferably rectangularly shaped. The inner or top edge of the canopy


14


is secured to the support wall


12


and the outer or bottom edge of the canopy


14


is secured to the roller assembly


16


. The inner and outer edges of the canopy


14


are preferably provided with an awning rope or other suitable cylindrical member. The awning rope is preferably a polypropylene rope and is preferably sewn in a hem or pocket formed at the edges of the canopy


14


.




The rope at the inner edge of the canopy


14


is preferably held by an awning rail


20


which horizontally extends along the support wall


12


and is rigidly secured to the support wall


12


by suitable fasteners. The awning rail


20


is preferably an aluminum extrusion having a channel formed therein for retaining the awning rope in a known manner. It is noted that the inner edge of the canopy


14


can be alternately secured to the support wall


12


in other manners such as, for example, directly to the support wall


12


or to a cover attached to the wall


12


. The awning rope at the outer edge of the canopy


14


is held by the roller assembly


16


as described in more detail hereinafter.




As best shown in

FIG. 4

, a suitable roller assembly


16


includes a roller tube


22


, a pair of end caps


24


closing open ends of the roller tube


22


, axles or bars


26


which rotatably support the roller tube


22


, and at least one torsion spring


28


. The roller tube


22


preferably has longitudinally extending channels or grooves formed therein so that the awning rope of the outer edge of the canopy


14


is secured to one of the grooves in a known manner.




Each end cap


24


is rigidly secured to the roller tube


22


for rotation therewith and has a central opening


30


therein. The bar


26


extends through the central opening


30


such that the roller tube


22


and the end cap


24


are free to rotate together with respect to the bar


26


. The bars


26


form a rotational axis


32


for the roller tube


22


and support the roller tube


22


. The torsion spring


28


is disposed around the bar


26


within the roller tube


22


. The torsion spring


28


is operably connected between the roller tube


22


and the bar


26


in any known manner so that rotation of the roller tube


22


with respect to the bars


26


varies tension of the torsion spring


28


. The torsion spring


28


, therefore, can be advantageously preloaded for biasing the roller tube


22


to roll-up the canopy


14


onto the roller tube


22


. Biased in this manner, the torsion spring


28


both tensions the canopy


14


when the awning


10


is held in the extended position and furls the canopy


14


onto the roller tube


22


when the awning


10


is moved from the extended position to the retracted position. It is noted that other configurations of roller assemblies and/or tensioning mechanisms can be utilized within the scope of the present invention.




The roller assembly


16


can also include a lock and release mechanism for selectively preventing rotation of the roller tube


22


in one direction or the other. The lock mechanism can be of any suitable type. See, for example, U.S. Pat. No. 5,732,756, disclosing a suitable lock mechanism for the roller assembly


16


. It should be noted that the lock mechanism is optional for the powered automatic awning and is generally not required because the arm assemblies


18


hold the roller assembly


16


in position as described in more detail hereinafter.




The bars


26


of the roller assembly


16


are supported by the arm assemblies


18


. Each arm assembly


18


is disposed in a generally vertical plane at an associated side edge of the canopy


14


and an associated end of the roller assembly


16


. The left and right arm assemblies


18


have essentially identical structures and therefore only one will be described in detail hereinafter.




As best shown in

FIGS. 5 and 6

, each arm assembly


18


is a four bar linkage including a first or base arm


34


, a second or bottom arm


36


, a third or extended arm


38


, and a fourth or top arm


40


. Each of the arms


34


,


36


,


38


,


40


are substantially straight and elongate and are fixed in length. The arms


34


,


36


,


38


,


40


are preferably extrusions of a light weight, high strength material such as an aluminum alloy.




The base arm


34


has a main wall


42


and inner and outer side walls


43


,


44


which perpendicularly extend from opposed side edges of the main wall


42


to form a vertically extending and outward facing channel


45


. The channel


45


is outward facing so that it at least partially receives the top and bottom arms


36


,


40


when in the retracted position (see FIGS.


1


and


1


A).




The base arm


34


is rigidly secured to the support wall


12


, preferably with top and bottom mounting brackets


46


,


47


. The mounting brackets


46


,


47


are preferably extrusions of a light weight, high strength material such as an aluminum alloy.




As best shown in

FIG. 19

, the top mounting bracket


46


extends from the open upper end of the base arm


34


. At the upper end of the base arm


34


, the side walls


43


,


44


are provided with openings for cooperating threaded fasteners


48


to rigidly attach the top mounting bracket


46


to the base arm


34


. The top mounting bracket


46


is preferably formed for receiving the threaded fasteners


48


. The top mounting bracket


46


has an inwardly extending top flange or hook member at an upper end thereof which can be advantageously located at a top rail of a recreational vehicle when the awning


10


mounted thereto. The top mounting bracket


46


is also provided with openings below the top flange for cooperating with threaded fasteners


49


to rigidly secure the top mounting bracket


46


to the support wall


12


.




As best shown in

FIGS. 20-22

, the lower end of the base arm


34


is preferably provided with a base arm extension


50


. The base arm extension


50


is substantially straight and elongate and is fixed in length. The base arm extension


50


cooperates with the base arm


34


so that the distance between the top and bottom mounting brackets


46


,


47


, which is the effective length of the base arm


34


, is variable as described in more detail hereinafter. The base arm extension


50


is preferably an extrusion of a light weight, high strength material such as an aluminum alloy.




The base arm extension


50


preferably has a generally H-shaped cross-section formed by a main wall


170


and inner and outer side walls


172


,


174


which perpendicularly extend from ends the main wall


170


. The base arm extension


50


is sized to fit within the channel


45


of the base arm


34


so that it can longitudinally move therein in a telescoping manner. Outwardly directed protrusions


176


are provided at the base of the side walls


172


,


174


which longitudinally extend along the length of the base arm extension


50


. The protrusions are


176


sized and shaped to cooperate with undercuts or grooves formed in the side walls


43


,


44


of the base arm


34


to interlock the base arm


34


and the base arm extrusion


50


together. Secured in this manner, the base arm


34


and the base arm extension are interlocked to together in a drawer-like manner such that they can only move longitudinally relative to one another.




At the lower end of the base arm


34


, the side walls


43


,


44


are provided with openings for cooperating threaded fasteners


51


to rigidly attach the base arm extension


50


to the base arm


34


. The side walls


172


,


174


of the base arm extension


50


are preferably provided with inwardly directed flanges


178


which longitudinally extend along the length of the base arm extension


50


. The flanges


178


are inwardly spaced apart from the main wall


170


to receive and secure the threaded fasteners


51


therebetween. The side walls of the base arm extension


50


can be provided with a plurality of longitudinally spaced-apart openings so that the position of base arm extension


50


relative to the base arm


34


can be adjusted to a plurality of positions. For example, there can be about six openings spaced-apart along intervals of about 1 to about 1.5 inches. Alternatively, the openings in the base arm extension side walls


172


,


174


can be custom drilled during installation using the openings in the base arm side walls


43


,


44


as pilots once the base arm extension


50


has been located in its desired position relative to the base arm


34


. It is noted that drilling the openings during installation provides infinite adjustability of the base arm extension


50


. It is also noted that the openings can be formed using self-drilling fasteners if the base arm extension


50


is formed of a suitable material.




The bottom mounting bracket


47


extends from the lower end of the base arm extension


50


. At the lower end of the base arm extension


50


, the main wall is provided with openings for cooperating threaded fasteners


52


to rigidly attach the bottom mounting bracket


47


to the base arm extension


50


. The bottom mounting bracket


47


is preferably formed for receiving the threaded fasteners


52


. The bottom mounting bracket


47


also an upwardly directed protrusion sized and shaped to cooperate with the main wall


170


and flanges


178


of the base wall extension


150


. The protrusion extends between the main wall


170


and the flanges to interlock the bottom mounting bracket


47


and the base arm extension


50


. The bottom mounting bracket


47


has an inwardly extending bottom flange or hook member at an lower end thereof which can be advantageously located at the box iron of a recreational vehicle when the awning


10


is mounted thereto. The bottom mounting bracket


47


is also provided with openings


180


for cooperating with threaded fasteners


53


to rigidly secure the bottom mounting bracket


47


to the support wall


12


.




It can be seen from the above description that the overall length of the base arm and base arm extension can be easily adjusted in a telescoping manner. Therefore, the awning


10


can be easily secured to support walls


12


having various dimensions such as a variety of different recreational vehicles.




As best shown in

FIGS. 5 and 6

, the bottom arm


36


has an inner end pivotally mounted to a central or intermediate portion of the base arm


34


. The bottom arm


36


is preferably tubular in cross-section and is provided with inner and outer end caps or plugs


54


,


56


secured to and closing the open inner and outer ends of the bottom arm


36


respectively. The end caps


54


,


56


are secured to the bottom arm in any suitable manner such as, for example, rivets or screws. The inner end cap


54


is provided with an opening for receiving a pivot shaft


58


therethrough. The pivot shaft


58


extends through the inner end cap


54


and openings


59


in the side walls


43


,


44


of the base arm


34


to form a pivot joint or rotatable connection therebetween. The pivot shaft


58


is preferably provided with suitable bearings


60


, such as the illustrated flanged sleeve bearings, and is preferably held in position by retaining rings


62


. The inner end cap


54


is optionally biased to a central position within the channel of the base arm


34


by spring washers located between the side walls


43


,


44


of the base arm


34


and flanges of the bearings


60


.




The extended arm


38


has an inner or lower end pivotally mounted to an outer or lower end of the bottom arm


36


and an outer or upper end connected to the end of the roller assembly


16


(best shown in FIG.


5


). The extended arm


38


is preferably channel-shaped in cross-section having a main wall


64


and inner and outer side walls


66


,


68


perpendicularly extending from opposed side edges of the main wall


64


to form a channel


69


. The channel


69


preferably faces upward when the awning


10


is extended so that it at least partially receives the bottom arm


36


therein when in the retracted or stored position (see FIGS.


1


and


1


A).




The outer end cap


56


of the bottom arm


36


is provided with an opening for receiving a pivot shaft


70


therethrough. The pivot shaft


70


extends through the outer end cap


56


and openings


72


in the side walls


66


,


68


of the extended arm


38


to form a pivot joint or rotatable connection therebetween. The pivot shaft


70


is preferably provided with suitable bearings


74


, such as the illustrated flanged sleeve bearings, and is preferably held in position by suitable retaining rings


76


. The outer end cap


56


is optionally biased to a central position within the channel of the extended arm


38


by spring washers located between the side walls


66


,


68


of the extended arm


38


and flanges of the bearings


74


.




As best shown in

FIG. 4

, the upper or outer end of the extended arm


38


supports the roller assembly


16


. The free end of the extended arm


38


is provided with an upper end cap


78


which has a socket into which the upper end of the support arm


38


is closely received and rigidly secured. The upper end cap


78


is preferably secured to the extended arm


38


by rivets, but can be alternatively secured in other manners.




The upper end cap


78


and the roller assembly bar


26


are preferably secured together in a manner which allows rotation of the bar


26


, relative to the upper end cap


78


, about only one axis which facilitates handling and misalignment. The bar


26


cannot rotate about the rotational axis


32


or the longitudinal axis


80


of the extended arm


38


. The bar


26


can, however, rotate about a pivot axis which is substantially perpendicular to both the pivot axis


32


and the longitudinal axis


80


of the extended arm


38


at the outer or upper end of the extended arm


38


. In the illustrated embodiment the pivot axis is formed by a pin


82


which extends through the bar


26


and the upper end cap


78


. The bar


26


and the upper end cap


78


, however, can be alternately joined in other suitable manners such as, for example, by a screw or tube rivet.




The top arm


40


has an inner or upper end pivotally mounted to an upper portion of the base arm


34


and an outer or lower end pivotally mounted to an intermediate portion of the extended arm


38


generally near the lower or inner end of the extended arm


38


. The top arm


40


is preferably tubular in cross-section and preferably has inner and outer end caps or plugs


84


,


86


secured to and closing the open inner and outer ends of the top arm respectively. The inner and outer end caps


84


,


86


are each provided with an opening for receiving a pivot shaft


88


,


90


therethrough. One pivot shaft


88


extends through the inner end cap


84


and openings


92


in the side walls


43


,


44


of the base arm


34


to form a pivot joint or rotatable connection therebetween. The other pivot shaft


90


extends through the outer end cap


86


and openings


94


in the side walls


66


,


68


of the extended arm


38


to form a pivot joint or rotatable connection therebetween. The pivot shafts


88


,


90


are each preferably provided with suitable bearings


96


,


98


, such as the illustrated flanged sleeve bearings, and are preferably held in position by suitable retaining rings


100


,


102


. The inner end cap


84


is optionally biased to a central position within the channel of the base arm


34


by spring washers located between the side walls


43


,


44


of the base arm


34


and flanges of the bearings


96


. The outer end cap


86


is optionally biased to a central position within the channel of the extended arm


38


by spring washers located between the side walls


66


,


68


of the extended arm


38


and flanges of the bearings


98


.




It is this system of pivotally attached bars or arms


34


,


36


,


38


,


40


which form a four-bar linkage that provides a support base which reaches out to support the roller assembly


16


and fold backs into a compact stack against the wall


12


, by stacking the tubular-shaped arms


36


,


40


within the channel-shaped arms


34


,


38


.




Each arm assembly


18


also includes a force producing member for outwardly pivoting the bottom arm


36


toward the extended position. In the illustrated embodiment, the force producing member is a powered linear actuator


104


which not only provides a force for outwardly pivoting the bottom arm


36


toward the extended position but also a force for pulling it back to the retracted position. A first counter-balance spring


106


and a second counter-balance spring


108


can be provided to reduce the force requirements of the actuator


104


as discussed in more detail hereinbelow. The powered linear actuator


104


is preferably an electric linear actuator. It is noted that the powered actuator


104


can be of alternative types such as, for example, a torsion actuator and can utilize alternative types of power such as, for example, mechanical, hydraulic, and pneumatic. A suitable electric linear actuator is Part Number LA 28.25 SR-400-24-02 available from LINAK Inc., Louisville, Ky. The actuator


104


of the illustrated embodiment is custom made with the desired length but alternatively an extension can be used to increase the length of a commercially-available standard-size actuator. Power for the actuator


104


can be provided by either the recreational vehicle power system or a separate independent power system and can be 24 VDC or preferably 12 VDC.




The actuator


104


is preferably mounted between the base arm


34


and the bottom arm


36


. A first end of the actuator


104


is mounted to the base arm


34


by an upper mounting bracket


112


. The upper mounting bracket


112


is secured to the side wall


43


of the base arm


34


at an upper portion thereof by any suitable manner such as, for example, rivets or screws. As best shown in

FIG. 3B

, the upper mounting bracket


112


is preferably an extrusion of a light weight, high strength material such as, for example, an aluminum alloy. The upper bracket


112


is preferably shaped to interlock with the base arm


34


and to have an outwardly directed flange


113


.




In the illustrated embodiment, the upper mounting bracket


112


is secured slightly below the pivot joint between the base arm


34


and the top arm


40


. A clevis


114


of the actuator


104


is pivotally connected to the flange


113


of the upper mounting bracket


112


in a suitable manner. The actuator


104


length of stroke and mounting position must be coordinated exactly with the 4-bar geometry of the arms


34


,


36


,


38


,


40


so that they open and close properly.




A second end of the actuator


104


is mounted to the bottom arm


36


by a lower mounting bracket


116


. As best shown in

FIG. 3A

, the lower mounting bracket


116


is preferably an extrusion of a light weight, high strength material such as, for example, an aluminum alloy. The lower mounting bracket


116


is preferably shaped to interlock with the bottom arm


36


and to have an outwardly directed flange


117


.




The lower mounting bracket


116


is secured to the bottom arm


36


at a central or intermediate portion thereof by any suitable manner such as, for example, rivets or screws. The lower mounting bracket


116


is secured between the pivot joint between the base arm


34


and the bottom arm


36


and the pivot joint between the bottom arm


36


and the extended arm


38


. A clevis


118


of the actuator extension


110


is pivotally connected to the lower mounting bracket


116


an any suitable manner. The side wall


43


of the base arm


34


is provided with a suitable cut-out or clearance opening


119


for the lower mounting bracket


116


when in the extended position.




As best shown in

FIGS. 7 and 8

, the first counter-balance spring


106


is preferably a compression, bowed leaf spring acting between the base arm


34


and the top arm


40


near the pivot joint between the base arm


34


and the top arm


40


. The first counter-balance spring


106


has an upper end secured to the base arm


34


and a lower free end engaging the top arm


40


. The upper end is provided with suitable openings


120


and is fastened to the base arm


34


with suitable fasteners


122


such as, for example, rivets or bolts. Mounted in this manner, the first counter-balance spring


106


applies a force which outwardly pivots the top arm


40


relative to the base arm


34


.




The first counter-balance spring


106


is compressed when the top arm


40


is downwardly pivoted into the channel


45


of the base arm


34


. In the retracted or flattened position, therefore, the single-leaf first counter-balance spring


106


stores energy which is at least partially released upon extension of the awning


10


. The illustrated first counter-balance spring


106


is a variable rate spring which has its highest force output when the top arm


40


is near the fully retracted position. As the first counter-balance spring


106


is compressed, it flattens against the base arm


34


to gain support and avoid over stress. As the support moves down on the first counter-balance spring


106


, the first counter-balance spring


106


gets shorter and stiffer to apply a higher force and improved assist for the actuator


104


.




The first counter-balance spring


106


is sized to provide a force which balances the inward pull of the roller assembly torsion spring


28


which has relatively low leverage when in the extended position and relatively high leverage when in the retracted position. The torsion spring


28


has a high mechanical advantage as the awning


10


approaches the wall


12


. The first counter-balance spring


106


, however, develops a high force as it is compressed at the support wall


12


to counter the high force of the torsion spring


28


. It should be noted that the actuator


104


has good mechanical advantage until it approaches the wall


12


, where it needs help. The mounting brackets


112


,


116


of the actuator


104


must be kept short, thus the poor leverage near the wall, so that the awning


10


is kept to a low profile in the retracted position. The first counter-balance spring


106


, therefore, reduces the force requirements of the actuator


104


because the actuator


104


does not have to overcome the inward pull of the roller assembly torsion spring


28


when initially moving the awning


10


away from the support wall


12


to move the awning


10


from the retracted position (

FIG. 2

) to the extended position (FIG.


3


).





FIGS. 9 and 10

illustrate an alternative first counter-balance spring


124


wherein a double leaf is utilized between the base arm


34


and the top arm


40


near the pivot joint between the base arm


34


and the top arm


40


. The double-leaf spring


124


preferably, has an inner leaf


124




a


and an outer leaf


124




b


mounted as a back-to-back pair. The twin-leaf design provides a long stroke and high force yet retracts into a tight space. Each leaf


124




a


,


124




b


is generally arcuate having upper ends joined together and lower ends secured to the base arm


34


and top arm


40


respectively. The upper ends are joined in any suitable manner, such as for example, welding. The lower ends are provided with openings


126


and fastened with suitable fasteners


128


(

FIG. 9

) such as, for example, rivets or bolts to the base and top arms


34


,


40


. Mounted in this manner, the double-leaf first counter-balance spring


124


applies a force which outwardly pivots the top arm


40


relative to the base arm


34


with no sliding contact on the arms


34


,


40


.




The inner and outer leaves


124




a


,


124




b


are compressed toward each other when the top arm


40


is downwardly pivoted into the channel


45


of the base arm


34


. The leaves


124




a


,


124




b


flatten against each other to support each other, to distribute stress, and to form a compact package. In the retracted or flattened position, the double-leaf first counter-balance spring


124


stores energy which is at least partially released upon extension of the awning


10


.




It should be noted that the configuration of single-leaf spring is simpler to produce and install. The single-leaf spring, however, has less stroke and greater stress than the twin-leaf spring and requires a suitable rub strip on the top arm


40


at the area of sliding contact.




The second counter-balance spring


108


is preferably a compression coil spring acting between the base arm


34


and the extended arm


38


above the pivot joint between the base arm


34


and the top arm


40


. The second counter-balance spring


108


is preferably secured to the base arm


34


by a generally cylindrical spring base or guide


130


. The spring base


130


is secured to the base arm


34


in any suitable manner such as, for example, screws. The free end of the second counter-balance spring


108


is preferably provided with a rubber bumper or guard


132


. Mounted in this manner, the second counter-balance spring


108


applies a force to outwardly pivot the extended arm


38


relative to the base arm


34


. It is noted that the second counter-balance spring


108


can alternatively be mounted on the top arm


40


to act between the top arm


40


and the extended arm


38


to outwardly rotate the extended arm


38


. The second counter-balance spring


108


, however, preferably engages the extended arm at the highest point possible so the torque arm is relatively large, thereby requiring a reduced spring force.




The second counter-balance spring


108


is sized to provide a force which offsets the increase in leverage of the roller assembly torsion spring


28


and the decrease in leverage of the actuator


104


as the extended arm


38


reaches the fully retracted position (best shown in FIG.


1


). The second counter-balance spring


108


, therefore, reduces the force requirements of the actuator


104


because an additional force is provided by the second counter-balance spring


108


when the torque arm of the actuator


104


is near its smallest length to help overcome the inward pull of the roller assembly torsion spring


28


when the actuator


104


is moving the awning


10


from the retracted position (

FIG. 2

) to the extended position (FIG.


3


). The second counter-balance spring


108


is only required when the actuator


104


and the first counter-balance spring


106


are not able to move the awning


10


away from the wall and/or the first counter-balance spring


106


alone does not adequately reduce the force requirements of the actuator


104


.




As best shown in

FIGS. 1 and 1A

, the top and bottom arms


36


,


40


are stacked within the base and extended arms


34


,


38


so that the awning


10


is in close relationship with the support wall


12


and the canopy


14


is fully rolled-up on the roller assembly


16


when the awning


10


is the retracted position. The base arm


34


and the extended arm


38


each have a substantially parallel relationship with the support wall


12


of the recreational vehicle. The bottom arm


36


and the top arm are each located partially within the base arm


34


and partially within the extended arm


38


. The first counter balance spring


106


is compressed between the base arm


34


and the top arm


40


and the second counter-balance spring


108


is compressed between the base arm


34


and the extended arm


38


. In this retracted position, the inactivated actuator


104


is locked to prevent movement of the arms


36


,


38


,


40


. A suitable travel lock may also be provided to secure the arms


36


,


38


,


40


in their retracted positions if desired.




To open the awning


10


, the operator manually unlocks the roller assembly lock if provided to permit the canopy


14


to unroll from the roller assembly


16


and manually unlocks the travel lock if provided to permit the arms


36


,


38


,


40


to open. The operator then activates the actuator


104


so that power is provided thereto and the actuator


104


begins to decrease in length. As the length of the actuator


104


decreases, the bottom arm


36


is upwardly rotated about its pivot joint with the base arm


34


.




As best shown in

FIG. 2

, the rotation of the bottom arm


36


and the resulting rotation of the top arm


40


, downwardly rotates the extended arm


38


about its pivot joint with the bottom arm


36


. As the top end of the extended arm


38


moves away from the wall


12


, the canopy


14


is unrolled from the roller assembly


16


.




Initially, both the first and second counter-balance springs


106


,


108


each assist the actuator


104


by supplying forces which balance the bias of the torsion spring of the roller assembly


16


. Once the extended arm


38


is no longer in contact with the second counter-balance spring


108


and the actuator


104


has an increased torque arm, the first counter balance spring


106


acts alone to balance the bias of the torsion spring of the roller assembly


16


.




As best shown in

FIG. 3

, the actuator


104


continues to decrease in length until the extended arm


38


is generally an extension of the bottom arm


36


, that is, the extended arm


38


and the bottom arm


36


are generally coaxial. The actuator


104


then stops and locks. In this position, the canopy


14


is fully extended and the awning


10


is in the deployed position. In this deployed position, the inactivated actuator


104


prevents inward movement of the arms


36


,


38


,


40


. Suitable locks may also be provided to further secure the arms


36


,


38


,


40


in their deployed positions if desired.




To close the awning


10


, the operator manually unlocks the roller assembly lock if provided to permit the canopy


14


to roll onto the roller assembly


16


and manually unlocks any additional locks if provided to permit the arms


36


,


38


,


40


to close. The operator then activates the actuator


104


so that power is provided thereto and the actuator


104


begins to increase in length. As the length of the actuator


104


increases, the bottom arm


36


is downwardly rotated about its pivot joint with the base arm


34


.




As best shown in

FIG. 2

, the rotation of the bottom arm


36


and the resulting rotation of the top arm


40


, upwardly rotates the extended arm


38


about its pivot joint with the bottom arm


36


. As the top end of the extended arm


38


moves toward the wall


12


, the canopy


14


is rolled back onto the roller assembly


16


by a slow and even movement. It is noted that the torsion spring provides a force which rotates the roller assembly


16


but is offset by the counter-balance springs


106


,


108


so that the actuator


104


controls the rate of movement of the awning


10


.




As best shown in

FIG. 1

, the actuator


104


continues to increase in length until the extended arm


38


is generally parallel with the base arm


34


and the wall


12


. The actuator


104


then stops with the arms


34


,


36


,


38


,


40


tight against the wall. In this position, the canopy


14


is fully furled up and the awning


10


is in the retracted position. The operator then locks the travel locks if provided.





FIGS. 11

to


14


illustrate a second embodiment of a retractable awning


140


according to the present invention wherein like reference numbers are used for like structure. The awning


140


is a spring-assisted manual awning which is attached to a vertically-extending support wall


12


such as the side of a recreational vehicle.




The awning


140


according to the second embodiment of the present invention is substantially the same as the awning according to the first embodiment of the present invention except that the force producing member for outwardly pivoting the bottom arm


36


toward the extended position is a spring


142


. The spring


142


is a tension coil spring but other suitable springs can be utilized such as, for example, a gas spring or a suitably configured assembly with compression coil spring or a compression gas spring (see

FIGS. 14A and 18

for examples of suitable configurations for compression springs). It is noted that the awning


140


also does not include the first or second counter-balance springs


106


,


108


, discussed with regard to the first embodiment, because the operator already has good mechanical advantage when pulling.




The spring


142


is mounted between the base arm


34


and the bottom arm


36


. A first end of the spring


142


is mounted to the base arm


34


by the upper mounting bracket


112


. An end loop


144


of the spring


142


is pivotally connected to the upper mounting bracket


112


an any suitable manner. A second end of the spring


142


is mounted to the bottom arm


36


by the lower mounting bracket


116


. A second end loop


146


of the spring


142


is pivotally connected to the lower mounting bracket


116


in any suitable manner.




The spring


142


is positioned and sized to counterbalance the torsion spring


28


of the roller assembly


16


. As noted above with regard to the first embodiment, there is an increase in leverage of the roller assembly torsion spring


28


and the decrease in leverage of the spring


142


as the extended arm


38


moves toward the retracted position (best shown in

FIG. 11

) but the operator has good leverage here. Also, there is a decrease in leverage of the roller assembly torsion spring


28


and the increase in leverage of the spring


142


as the extended arm


38


moves toward the extended position (best shown in

FIG. 13

) and the operator needs help here. As the awning


140


is extended, stored energy in the spring


142


assists deployment and is transferred to the torsion spring


28


of the roller assembly


16


. As the awning


140


is retracted, stored energy in the torsion spring


28


of the roller assembly


16


assists retraction and is transferred to the assist spring


142


.




Because the awning


140


is a manual awning, the roller assembly


16


includes a pull strap


148


. The pull strap


148


is preferably secured to one of the grooves of the roller tube


22


in a known manner. The pull strap


148


wraps around the roller tube


22


within the canopy


14


when the canopy


14


is rolled-up on the roller tube


22


so that a looped end slightly extends out of the canopy


14


when the canopy


14


is fully rolled-up onto the roller tube


22


(FIG.


11


).




To open the awning


140


, the operator manually unlocks the roller assembly


16


to permit the canopy


14


to unroll from the roller assembly


16


and manually unlocks the travel lock. The operator grasps the awning pull strap


148


and pulls to move the roller assembly


16


away from the support wall


12


and unroll the canopy from the roller assembly


16


.




As best shown in

FIG. 12

, the rotation of the bottom arm


36


and the resulting rotation of the top arm


40


, downwardly rotates the extended arm


38


about its pivot joint with the bottom arm


36


. As the top end of the extended arm


38


moves away from the wall


12


, the canopy


14


is unrolled from the roller assembly


16


. As the bottom arm


36


is upwardly rotated about its pivot joint with the base arm


34


the leverage of the spring


142


increases and assists deployment by supplying a force which counter-balances the torsion spring


28


of the roller assembly


16


.




As best shown in

FIG. 13

, the spring continues to decrease in length until the extended arm


38


is generally an extension of the bottom arm


36


, that is, the extended arm


38


and the bottom arm


36


are generally coaxial. The spring


142


is then unloaded or nearly unloaded. In this position, the canopy


14


is fully extended and the awning


10


is in the deployed position. In this deployed position, the spring


142


pulls upwardly lightly on the bottom arm


36


, the canopy


14


pulls tight between the awning rail


20


and the roller assembly


16


, and the roller assembly lock prevents the canopy


14


from rolling back onto the roller assembly


16


. A suitable additional lock may also be provided to secure the arms


36


,


38


,


40


in their deployed positions if desired.




To close the awning


10


, the operator grasps the pull strap and manually unlocks the roller assembly


16


, and manually unlocks any additional locks if provided, to permit the canopy


14


to roll onto the roller assembly


16


. The bias provided by the torsion spring


28


rolls the canopy onto the roller assembly


16


and pulls the roller assembly


16


toward the wall


12


. As the roller assembly


16


moves toward the wall


12


, the bottom arm


36


is downwardly rotated about its pivot joint with the base arm


34


and the length of the spring


142


is increased to store energy therein for later deployment.




As best shown in

FIG. 12

, the rotation of the bottom arm


36


and the resulting rotation of the top arm


40


, upwardly rotates the extended arm


38


about its pivot joint with the bottom arm


36


. As the top end of the extended arm


38


moves toward the wall


12


, the canopy


14


is rolled back onto the roller assembly


16


.




As best shown in

FIG. 11

, the torsion spring


28


rotates the awning


10


until the extended arm


38


is generally parallel with the base arm


34


and the support wall


12


. In this position, the canopy


14


is fully furled up and the awning


10


is in the retracted position. The operator then locks the travel lock if provided to prevent outward movement of the arms


36


,


38


,


40


.





FIGS. 15

to


18


illustrate a third embodiment of a retractable awning


150


according to the present invention wherein like reference numbers are used for like structure. The awning


150


is a spring-assisted manual awning which is attached to a vertically-extending support wall


12


such as the side of a recreational vehicle.




The awning


150


according to the third embodiment of the present invention is substantially the same as the awning


140


according to the second embodiment of the present invention except that the force producing member is a compression gas spring


152


. A suitable gas spring is available from Suspa, Inc., Grand Rapids, Mich. The spring


152


illustrates that configurations with compression springs can be utilized and that other types of springs such as gas springs can be utilized. It is noted that the awning


150


also does not include the first or second counter-balance springs


106


,


108


discussed with regard the first embodiment because, as with the second embodiment, the operator already has good mechanical advantage when pulling.




Because the spring


152


is a compression spring, it is mounted between the base arm


34


and the top arm


40


. A first end of the spring


152


is mounted to the base arm


34


by a mounting bracket


154


. The mounting bracket


154


is secured to the side wall


43


of the base arm


34


at an intermediate portion thereof by any suitable manner such as, for example, rivets or screws. In the illustrated embodiment, the lower mounting bracket


154


is secured at the pivot joint between the base arm


34


and the bottom arm


36


. The spring


152


is provided with pivotable ball end joints


156


,


158


. A second end of the spring


152


is mounted to the top arm


40


at a central or intermediate portion thereof by any suitable manner such as, for example, a threaded stud of the end joint


158


. The side wall


43


of the base arm


34


is provided with a suitable cut out or clearance opening


160


for the end joint when in the retracted position.




In the illustrated awning


150


, the spring


152


is mounted with the cylinder portion secured to the top arm


40


and the rod portion secured to the base arm


34


. It is noted, however, that the spring can alternatively be mounted in the reverse orientation, that is, with the rod portion secured to the top arm


40


and the cylinder portion secured to the base arm


34


. This reverse orientation may be particularly advantageous when the awning


150


is secured to a recreational vehicle to protect against road splash.




The spring


152


is positioned and sized to counterbalance the torsion spring


28


of the roller assembly


16


. As noted above with regard to the first and second embodiments, there is an increase in leverage of the roller assembly torsion spring


28


and the decrease in leverage of the spring


142


as the extended arm


38


moves toward the retracted position (best shown in

FIG. 15

) but the operator has good leverage here. Also, there is a decrease in leverage of the roller assembly torsion spring


28


and the increase in leverage of the spring


142


as the extended arm


38


moves toward the extended position (best shown in

FIG. 17

) and the operator needs help here. As the awning


140


is extended, stored energy in the spring


152


assists deployment and is transferred to the torsion spring


28


of the roller assembly


16


. As the awning


150


is retracted, stored energy in the torsion spring


28


of the roller assembly


16


assists retraction and is transferred to the spring


152


.




To open the awning


150


, the operator manually unlocks the roller assembly


16


to permit the canopy


14


to unroll from the roller assembly


16


and manually unlocks the travel lock. The operator grasps the awning pull strap


148


and pulls to move the roller assembly


16


away from the support wall


12


and unroll the canopy from the roller assembly


16


.




As best shown in

FIG. 16

, the rotation of the top arm


40


and the resulting rotation of the bottom arm


36


, downwardly rotates the extended arm


38


about its pivot joint with the bottom arm


36


. As the top end of the extended arm


38


moves away from the wall


12


, the canopy


14


is unrolled from the roller assembly


16


. As the top arm


40


is upwardly rotated about its pivot joint with the base arm


34


the leverage of the spring


152


increases and assists deployment by supplying a force which counter-balances the torsion spring


28


of the roller assembly


16


.




As best shown in

FIG. 17

, the spring continues to increase in length until the extended arm


38


is generally an extension of the bottom arm


36


, that is, the extended arm


38


and the bottom arm


36


are generally coaxial. The spring


152


is then unloaded or nearly unloaded. In this position, the canopy


14


is fully extended and the awning


10


is in the deployed position. In this deployed position, the spring


152


pushes upwardly lightly on the top arm


40


, the canopy


14


pulls tight between the awning rail


20


and the roller assembly


16


, and the roller assembly lock prevents the canopy


14


from rolling back onto the roller assembly


16


. A suitable additional lock may also be provided to secure the arms


36


,


38


,


40


in their deployed positions if desired.




To close the awning


10


, the operator grasps the pull strap


148


and manually unlocks the roller assembly


16


, and manually unlocks any additional locks if provided, to permit the canopy


14


to roll onto the roller assembly


16


. The bias provided by the torsion spring


28


rolls the canopy onto the roller assembly


16


and pulls the roller assembly


16


toward the wall


12


. As the roller assembly


16


moves toward the wall


12


, the top arm


40


is downwardly rotated about its pivot joint with the base arm


34


and the length of the spring


152


is decreased to store energy therein for later deployment.




As best shown in

FIG. 16

, rotation of the top arm


40


and the resulting rotation of the bottom arm


36


, upwardly rotates the extended arm


38


about its pivot joint with the bottom arm


36


. As the top end of the extended arm


38


moves toward the wall


12


, the canopy


14


is rolled back onto the roller assembly


16


.




As best shown in

FIG. 15

, the torsion spring


28


rotates the awning


10


until the extended arm


38


is generally parallel with the base arm


34


and the wall


12


. In this position, the canopy


14


is fully furled up and the awning


10


is in the retracted position. The operator then locks the travel lock if provided to prevent outward movement of the arms


36


,


38


,


40


.




Although particular embodiments of the invention have been described in detail, it will be understood that the invention is not limited correspondingly in scope, but includes all changes and modifications coming within the spirit and terms of the claims appended hereto.



Claims
  • 1. An automatic awning for mounting to a wall, said automatic awning comprising:a roller assembly including a torsion spring; a flexible canopy having an inner edge for connection to the wall and an outer edge secured to said roller assembly; and a pair of arm assemblies supporting opposite ends of said roller assembly and operable to move said roller assembly between a retracted position adjacent the wall and an extended position spaced from the wall, said torsion spring of said roller assembly biasing said roller assembly toward the retracted position, each of said arm assemblies comprising: a vertically extending base arm for connection to the wall; a bottom arm having a first end pivotally connected to said base arm; an extended arm having a first end pivotally connected to said bottom arm and a second end connected to and supporting said roller assembly; a top arm having a first end pivotally connected to said base arm above said bottom arm and a second end pivotally connected to said extended arm; and a powered actuator connected to said base arm and extending between said base arm and said bottom arm for pivoting said bottom arm to move the roller assembly between the retracted position and the extended position, said powered actuator providing a force for moving the roller assembly to the extended position and an oppositely-directed force for moving the roller assembly to the retracted position.
  • 2. The automatic awning of claim 1, wherein the powered actuator decreases in length to provide the force to move the bottom arm toward the extended position.
  • 3. The automatic awning of claim 2, wherein the powered actuator increases in length to provide the oppositely-directed force to move the bottom toward the retracted position.
  • 4. The automatic awning of claim 3, wherein the powered actuator is an electric linear actuator.
  • 5. An automatic awning for mounting to a wall, said automatic awning comprising:a roller assembly including a torsion spring; a flexible canopy having an inner edge for connection to the wall and an outer edge secured to said roller assembly; and a pair of arm assemblies supporting opposite ends of said roller assembly and operable to move the roller assembly between a retracted position adjacent the wall and an extended position spaced from the wall, said torsion spring of said roller assembly biasing said roller assembly toward the retracted position, each of said arm assemblies comprising: a vertically extending base arm for connection to the wall; a bottom arm having a first end pivotally connected to said base arm; an extended arm having a first end pivotally connected to said bottom arm and a second end connected to and supporting said roller assembly, said extended arm having a pair of side walls extending from opposing side edges of a main wall to define a channel that at least partially receives the bottom arm when the roller assembly is in the retracted position; a top arm having a first end pivotally connected to said base arm above said bottom arm and a second end pivotally connected to said extended arm; and a powered actuator connected to said base arm and extending between said base arm and said bottom arm for pivoting said bottom arm to move the roller assembly between the retracted position and the extended position.
  • 6. The automatic awning of claim 5, wherein the base arm has a pair of side walls extending from opposing side edges of a main wall to define a channel that at least partially receives the top and bottom arms when the roller assembly is in the retracted position.
  • 7. The automatic awning of claim 5, wherein the powered actuator provides a force for moving the roller assembly to the extended position and an oppositely-directed force for moving the roller assembly to the retracted position.
  • 8. The automatic awning of claim 7, wherein the powered actuator decreases in length to provide the force to move the bottom arm toward the extended position.
  • 9. The automatic awning of claim 8, wherein the powered actuator increases in length to provide the oppositely-directed force to move the bottom toward the retracted position.
  • 10. The automatic awning of claim 9, wherein the powered actuator is an electric linear actuator.
  • 11. An automatic awning for mounting to a wall, said automatic awning comprising:a roller assembly including a torsion spring; a flexible canopy having an inner edge for connection to the wall and an outer edge secured to said roller assembly; and a pair of arm assemblies supporting opposite ends of said roller assembly and operable to move the roller assembly between a retracted position adjacent the wall and an extended position spaced from the wall, said torsion spring of said roller assembly biasing said roller assembly toward the retracted position, each of said arm assemblies comprising: a vertically extending base arm for connection to the wall, said base arm having a pair of side walls extending from opposing side edges of a main wall to form a channel; a bottom arm having a first end pivotally connected to said base arm; an extended arm having a first end pivotally connected to said bottom arm and a second end connected to and supporting said roller assembly; a top arm having a first end pivotally connected to said base arm above said bottom arm and a second end pivotally connected to said extended arm, said top arm being at least partially received in the channel formed in the base arm when the roller assembly is in the retracted position; and a powered actuator connected to said base arm and extending between said base arm and said bottom arm for pivoting said bottom arm to move the roller assembly between the retracted position and the extended position.
  • 12. The automatic awning of claim 11, wherein the bottom arm is at least partially received in the channel formed in the base arm when the roller assembly is in the retracted position.
  • 13. The automatic awning of claim 11, wherein the powered actuator provides a force for moving the roller assembly to the extended position and an oppositely-directed force for moving the roller assembly to the retracted position.
  • 14. The automatic awning of claim 13, wherein the powered actuator decreases in length to provide the force to move the bottom arm toward the extended position.
  • 15. The automatic awning of claim 14, wherein the powered actuator increases in length to provide the oppositely-directed force to move the bottom-toward the retracted position.
  • 16. The automatic awning of claim 15, wherein the powered actuator is an electric linear actuator.
  • 17. The automatic awning of claim 1, further comprising a bracket mounting a first end of the actuator to the base arm.
CROSS-REFERENCE TO RELATED APPLICATION

This is a continuation of application Ser. No. 09/137,201 filed Aug. 20, 1998, now U.S. Pat. No. 6,095,221.

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Continuations (1)
Number Date Country
Parent 09/137201 Aug 1998 US
Child 09/519779 US