CA2057615C

CA2057615C - Spring-biased gate assembly

Info

Publication number: CA2057615C
Application number: CA 2057615
Authority: CA
Inventors: Ronald Lubinski
Original assignee: Individual
Current assignee: Individual
Priority date: 1991-12-13
Filing date: 1991-12-13
Publication date: 1996-10-08
Anticipated expiration: 2011-12-13
Also published as: CA2057615A1

Abstract

A gate assembly includes a stationary support with upper and lower apertured brackets. A gate has a tubular upright whose open upper and lower ends are received by the brackets. End caps extend into the open upright ends and seat against the brackets to secure the gate to the support for rotation about a vertical rotational axis. Upper and lower coil springs are mounted within the upright in alignment with the rotational axis. The end caps have slots which receive and secure one end of each spring to the support. An internal shaft is fixed to the upright between the coil springs. It has vertical slots that receive and secure an opposite end of each spring to the tubular upright for rotation with the gate. The end caps can be rotated and fixed to the brackets with bolts to adjust tension in the springs and consequently the rest position of the gate relative to the support. The springs wind in a common direction to ensure bidirectional operation.

Description

2~61~
SPRING-BIA~T~l ) ~ATF, ~9~c~FMRLy FIF T n OF TTTF. ~ON
The invention relates generally to gates and has particular application to gate assemblies intended for scaffolds.
S BACT~GROUNT~ OF TTTF~ INVF,NTIOI~
Safety regulations require a gate assembly at any opening to an elevated section of a scaffold. The gate assembly is normally required to open only in a single direction, into the scaffold structure, and to close ~lltrm~ir~lly to prevent falls. It will commonly include a gate of tubular frame . . ~"~ " .
10 and a post to which one side edge of the gate is hinged. Another post or ~U~ dl,l~, structure defines a stop that engages an opposite side edge of the gate. The position of the stop determines whether the gate opens clockwise or ~ullL~l~,lo~ wis~ Fxposed coil springs are often extended horizontally between the supporting post and the gate to bias the gate to a closed orientation 15 against the stop.
There are several shortcomings to such gates. The exposed spring l,Ull~llU'_~ilJll is subject to damage and to catching. The gate also tends to slam against the stop. When several workmen are climbing in succession through the gate, there is a risk that the gate may strike a workman with 20 sufficient force injure him or knock him from the scaffold.
SUMMARY OF TTTF. INVF.~TION
In one aspect, the invention provides a g,,ate assembly comprising a support structure and a gate including a tubular upright with upperand lower open ends. The support structure includes means supporting the 25 upright for relative rotation about a generally vertical rotational axis that extends centrally through the upright. A mechanism is provided to urge the gate to an adjustable rest position relative to the support structure. The mechanism ~L

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comprises upper and lower coil springs located within the upright in alignment with the rotational axis. The lower end of the upper spring and the upper end ofthe lower spring are fl~ed to the tubular upright for rotation therewith about the rotational axis. The mechanism also comprises upper and lower rotary 5 elements, which are preferably caps closing the tubular upright, that mount atthe upper and lower open ends of the tubular upright and rotate relative to the tubular upright about the rotational axis. The upper rotary element engages the upper end portion of the upper coil spring such that the spring end portion rotates with the upper rotary element, and the lower rotary element engages the 10 lower end portion of the lower coil spring such that the spring end portion rotates with the upper rotary element. The mechanism includes means that separately and releasably secure each rotary element to the support structure toprevent rotation of the rotary elements, and ~ "ly the spring end portions engaged by the rotary elements, with the tubular upright. The rotary 15 elements can be rotated to effectively adjust the torsional tension separately in each spring. The rest position of the gate relative to the support structure canthus be set by rotating the rotary elements relative to the tubular upright and then securing the rotary elements to the supporting structure.
The springs are preferably wound in a common direction (being 20 both left-hand or both right-hand springs). The inventor has observed that a coil spring tends to have a directional bias. When the opposite ends of the spring aue rotated relative to one another in a direction that tends to contract the spring radially, the spring tends to resist rotation strongly. When rotated in an opposite direction, the spring displays considerably less resistance to such 25 rotation. In a gate of the construction above, because a particular end of each spring is held relatively stationary and the opposite end rotates with the gate,using springs wound in a common direction ensures that the gate's operation is "bi-directional", substantially identical regardless whether it is opened =. .
i.

20576~5 clockwise or collnfp~ kwise.
A stop separate from the gate assembly will normally allow the gate to open only in a single direction. The rest position of the gate relative to the support will normally be set to coincide with the closure orientation of theS gate against the stop. The gate will ~,u~Ls~,~u~ ly tend to close reliably to its position against the stop, but will not slam against the stop like the prior artgates described above.
Other aspects of tbe invention will be apparent from a description below of a preferred C~lllbUI'- ' and will be more specifically 10 deflned in the appended claims.
DESCRTI~ON OF TTTF, DRAWINGS :
The invention will be better understood with reference to drawings in which:
fig. 1 is a perspective view of a gate assembly embodying the 15 invention;
fig. 2 is a fragmented perspective view detailing connection of a tubular upright of a gate gate to an upper bracket associated with a support post;
fig. 3 is a fr~gmPnf~fl, exploded view of the gate assembly;
fig. 4 is a fragmented view in partial vertical cross-section 20 detailing mounting of a spring assembly within the tubular upright;
fig. 5 is a view along the lines 5-5 of fig. 1;
fig. 6 is a view along the lines 6-6 of fig. 4; and, figs. 7a and 7b are ~ ,,. ," " " 1 ~ plan views showing the gate assembly uuu~ Lillg with a stop post to open only in a clockwise direction or counter 25 clockwise direction.
DESCl~ION OF PRF,FF,RRF,D FMRoDll\/rF~Ts Reference is made to fig. I which illustrates a gate assembly 10 embodying the invention. The gate assembly 10 includes a suppon structure ., .

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comprising a steel support post 12 and upper and lower U-channeled brackets 14, 16. The brackets 14, 16 are welded to the post 12 and reinforced with upper and lower triangular webs 18, 20. A welded, tubular steel gate 22 is mounted between the brackets 14. 16.
S The mounting of the gate 22 is apparent in figs. 3 and 4. The gate 22 includes an upright 24 with upper and lower open ends 26, 28. The upright's ends 26, 28 are received in a pair of vertically-aligned openings 30, 32 formed in the brackets 14, 16 and illustrated in phantom outline in fig. 3.
As apparent in fig. 4, the upright's upper end 26 is received within the opening30 in the upper bræket 14 terminating marginally short of the upper surfæe of the bracket 14. The upright's lower end 28 is similarly received in the opening 32 of the lower bracket 16 (although not illustrated). Upper and lower end caps 34, 36 seat over the bracket openings 30, 32 and are bolted to the brackets 14, 16 to retain the gate 22 in such an orientation. This permits rotation of the gate 22 about a generally vertical axis 38 that extends centrally through the upright24.
Upper and lower coil springs 40, 42 are located within the tubular upright 24, vertically aligned with the rotational axis 38. Each of the springs 40, 42 is preferably formed of stainless steel wire. It might typically have an outer diameter of I inch, a wire diameter of 1/8 inches, a pitch of about 5/8 inches, and a length of about 7 inches. Spring ~ should, however, be selected æcording to the ~ U;~ llL~ of a particular gate. Both springs 40, 42 are wound clockwise (when viewed from above each appears to spiral downwardly in a clockwise direction as apparent in fig. 3 and particularly fig. 6). This i~ ntif n ~tion of spring winding direction is entirely arbitrary, and the important point to note is that both springs wind in the same direction. Theupper and lower end portions 44, 46 of the upper spring 40 are bent to extend ~ 2057~1~
across the diameter of the spring 40 to facilitate spring retention. This ~" ~ gf .. l l. ,1 is apparent in fig. 6, where the upper end portion 44 0f the upper spring 40 can be seen.
The springs 40, 42 are secured to the support structure and to S the tubular upright 24 to function essentially as torsion springs. Each spring 40 or 42 is retained within a pair of elongate vertical slots defined by the end caps 34, 36 and a shaft 52 located within the tubular upright 24. A first pair of upper and lower slots 54, 56 (apparent in fig. 3) are intended to receive, ~ ,ly, the upper and lower end portions 44, 46 of the upper spring 40. A second pair of upper and lower slots 58, 60 are intended to receive, respectively, the upperand lower end portions 48, 50 the lower spring 42. The spacing and configuration of the paired slots permits lengthwise extension and contraction of the springs 40, 42. With respect to the upper spring 40, it will be noted in fig.
4 that its upper end portion 44 is normally located roughly rnid-way along the slot 54, allowing for lengthwise extension and contraction without ~
from the slot 54. Although not illustrated, the upper end portion 44 of the lower spring 42 is similarly onented relative to the slot 58 in which it is received.
The shaft 52 serves as a spring-retaining structure within the tubular upright 24. It has upper and lower end portions 62, 64 that are stepped down in order to be received within the springs 40, 42. The upper shaft end portion 62 defines the slot 56 that receives the lower end portion 46 of the upper spring 40 (as apparent in fig. 4). The lower shaft end portion 64 similarly defines the slot 58 that receives the upper end portion 48 of the lower spring 42. A sleeve 66 spaces the shaft 52 from the interior of the tubular upright 24 and provides a measure of clearance for radial expansion of the springs 40, 42 in response to gate rotation. The sleeve 66 might nlt~ Liv~ly be formed as an integral part of the shaft 52. As apparent in fig. 5, a continuous 20~761~
passage (not indicated by reference numeral) extends through the upright 24, sleeve 66 and shaft 52, and a rivet 67 extends through the passage to secure these ~ for rotation together. The shaft 52 ~ u,u~llLly secures the lower end portion 46 of the upper spring 40 and the upper end portion 48 of the S lower spring 42 lo the uprighl 24 for rotation with the upright 24 about the rotational axis 38.
The end caps 34, 36 secure the upper end portion 44 of the upper spring 40 and the lower end portion 50 of the lower spring 42 to the support and hold them against rotation with the tubular upright 24. The upper end cap 34 is typical. It comprises a washer defining a head portion 68 that seats against the upper surface of the upper bracket 14. It also includes a generally cylindrical body portion 70 that is welded to the washer. The body portion 70 is received in the open upper end 26 of the tubular upright 24. As apparent in fig. 4, it defines the slot 54 that receives the upper end portion 44 of the upper spring 40. The lower end cap 36 seats against the lower surfæe of the lower bracket 16 and defines the slot 60 that receives the lower end portion50 of the lower coil spring 42. The upper end cap 34 is releasably attached to the upper bracket 14 with a pair of socket bolts 72, 74.
Torsional tension in the springs 40, 42 can be adjusted by rotating the end caps34, 36. The term "torsional tension" should be understood as tension produced by rotating one end portion of a spring relative to an opposite end portion. Thel~,L.Li~ between the upper end cap 34 and the upper end of the upper spring 40 is typical. The upper end cap 34 is of course shaped to rotate relative to the upper open end 26 of the tubular upright 24. It is formed with two ~ ulllr~ lLidlly oriented slots 76, 78, as apparent in fig. 2. The upper bracket14 is formed with a pair of threaded holes (apparent in fig. 4, but not designated with reference numerals) positioned to register with the slots 76, 78. The two socket bolts 72, 74 are extended through the slots 76. 78 and threaded into the 205761~
two holes of the upper bracket 14 to fix the cap 34 to the bracket 14 (as apparent in fig. 4). To adjust tension in the upper spring 40, the two bolts 72, 74 are loosened or removed, and the upper end cap 34 is rotated (rotating the upper end portion 44 of the upper spring 40 relative to its lower end portion 46) either 5 to increase or decrease torsional tension. The two bolts 72, 74 are then tightened to fix the cap 34 to the upper bracket 14. In place of the slots 76, 78, a number of circumferentially-spaced circular clearance holes may be provided in the cap 34, but slots 76, 78 are preferred because they permit relatively continuous, rather than incremental, adjustment of spring tension and also 10 simplify assembly.
How iUlU~ C~ of the gdte assembly 10 are Ill~lura~ul~;d will be readily apparent. Assembly is essentially as follows. The passage through the tubular upright 24, spacing sleeve 66, and shaft 52 that is required to receive the rivet 27 may be pre-drilled in the individual ~ l~o~ . The support 15 structure may be laid horizontally on a floor. The gate 22 is ~IU~Iit~ly ' ' ' SO that the upper and lower ends 26, 28 of the tubular upright 24 are received in the apertures 30, 32 of the upper and lower brackets 14, 16.
The shaft 52 and sleeve are inserted into the tubular upright 24 and positioned so that the rivet 67 can then be inserted into the passage through the assembly of the upright 24, shaft 52 and sleeve 66. The rivet 67 is then set. The spring 40 may then be inserted into the upper end 26 of the tubular upright 24 and its lower end portion 46 engaged with the slot 56 of the shaft 52. The upper end cap 34 may then be located against the upper bracket 30 with its slot 54 engagedwith the upper end portion 44 of the spring 40 and fixed to the upper bracket 30with the socket bolts 72, 74. The lower spring 42 and the lower end cap 36 may be similarly installed.
OAce b o e~a i i~embl~ l ~ bas becn ~ssomblod, ~si d in one 2057~15 or both springs 40, 42 may be adjusted to set the natural rest position of the gate 22 relative to the support structure. Most ,,~ will require the gate 22 and support structure to be substantially co-planar, when the gate 22 is in its rest or closure orientation (as shown in solid outline in fig. 7a). To that end, S the post 12 may be maintained in a vertical orientation. Eæh end cap 34 or 36 may be loosened from its respective bræket 14 or 16 and rotated until the rest orientation of the gate 22 is substantially coplanar with the support post 12 and brackets 14, 16. Each cap 34 or 36 is then fastened against rotation to the brackets 14, 16. To install the gate assembly 10, the support post 12 may be 10 incorporated in a ,~JUVC~ iUll~l manner into the structure of a scaffold. If the gate 22 is to assume an alternative closure orientation in a particular application, spring tension may be adjusted on site to produce a different angular orientation between the gate 22 and the support structure when the gate æ is in its rest position.
Fig. 7a shows the gate assembly 10 cooperating with a stop post 80 such that the gate 22 opens only in a clockwise direction (as viewed from above). Three positions are illustrated. The rest position of the gate 22 proximate to the stop post 80 is shown in solid outline at 82. A wide open position ot the gate 22 relative to the support structure is shown in phantom 20 outline at 84. An in~rm~ position is shown at 86. In the process of manually rotating the gate 22 to its wide-open position 84, the lower end portion 46 of upper spring 40 is rotated clockwise relative to the spring's stationary upper end portion 44. This causes the upper spring 40 to contræt radially, strongly resisting opening of tbe gate and urging the gate 22 to its rest 25 position prox;mate to the stop post 80. The upper spring 40 sim~ n~ y expands axially along the slot 54 of the upper end cap 34. In the lower spring 42, the spring's upper end portion 48 is rotated clockwise relative to the spring's stationary lower end portion 50. The lower spring 42 ,. .,~c~ ly = ' 2~57~15 tends to expand radially and tends to contract axially along the slot 58. Its resistance to the rotation of the gate 22 is relatively low. The magnitude of the restoring torque urging the gate 22 to its rest position 82 is indicated with curved arrows of different size proximate to the various gate positions of fig. 7a 5 (no exact depiction of magnitude being intended). It has a maximum value in the wide open position 84, a reduced value at the i ~ ' ' position 86, and substantially a zero value at the rest position 82 which is important to ensuring that the gdte 22 does not slam against the stop post 80. As the gate 22 closes, the radial and axial contraction and expansion of the springs 40, 42 is reversed 10 until they restore to a rest orientation.
In fig. 7b, the stop 80 is positioned to allow the gate 22 to open only in a counter-clockwise direction. The operation of the springs 40, 42 is essentially reversed, the lower spring 42 now being dominant. The upper end portion 48 of the lower spring 42 is rotated counter-clockwise relative to the 15 spring's stationary lower end portion 50. The lower spring 48 ~ y contracts radially, strongly resisting opening of the gate (and cimlllt~n/~o~ y contracts axially). The upper spring 40 expands radially and contracts axially.
It should be noted that securing the end portions of the springs 40, 42 to the support structure and to the tubular upright 24, as described, and using springs 20 40, 42 wound in a common direction ensures such bi-directional operation.
Several advantages should be noted. The spring-biased mechanism for closing the gate 22 is compact and completely concealed within the tubular upright 24. Damage and catching are prevented. Adjustment of spring tension allows the rest position of the gate 22 to be set in a more precise 25 manner, ensuring that the torque on the gate 22 reaches a zero value proximate to a stop, reducing slamming and potential injury to workers approaching the gate 22 when opened. Use of springs 40, 42 wound in the same direction ensures that the gate assembly 22 operates in a similar manner regardless of the =:~

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direction in which the gate 22 is rotated. Permitting axial contraction and elongation of the springs 40, 42 is expected to enhance the working life of the springs 40, 42.
It ~ill be appreciated that a particular ~mh~ ~- of the 5 inventionhasbeendescribedandthat,.,...1;1;.~l;.,..~maybemadetherein without departing from the spirit of the invention or necessarily departing f}om the scope of the appended claims.

Claims

1. A gate assembly comprising:
a gate comprising a tubular upright with upper and lower open ends;
a support structure adapted to support the gate, the support structure comprising means supporting the upright for rotation relative to the support structure about a generally vertical rotational axis that extends centrally through the tubular upright; and, a mechanism for urging the gate to an adjustable rest position relative to the support structure, the mechanism comprising:
(a) upper and lower coil springs located within the upright in alignment with the rotational axis, each of the springs having an upper end portion and a lower end portion;
(b) means securing the lower end portion of the upper spring and the upper end portion of the lower spring to the tubular upright for rotation with the tubular upright about the rotational axis;
(d) upper and lower rotary elements mounted at the upper and lower open ends of the tubular upright and shaped for rotation relative to the tubularupright about the rotational axis, the upper rotary element engaging the upper end portion of the upper coil spring such that the upper end portion of the upper coil spring rotates with the upper rotary element, the lower rotary element engaging the lower end portion of the lower coil spring such that the lower end portion of the lower coil spring rotates with the lower rotary element; and, (e) means separately and releasably securing each of the rotary elements to the support structure thereby to prevent rotation of the rotary elements and the spring end portion engaged by the rotary element with the tubular upright;

whereby, the rest position of the gate relative to the support structure can be set by rotating the rotary elements relative to the tubular upright and then securing the rotary elements to the supporting structure.

2. The gate assembly of claim 2 in which:
the upper rotary element is a cap comprising a head portion that closes the upper open end of the tubular structure, and a body portion that extends downward into the tubular structure to engage the upper end portion of the upper spring; and, the lower rotary element is a cap comprising a head portion that closes the lower open end of the tubular structure, and a body portion that extends upward into the tubular structure to engage the lower end portion of thelower spring.

3 . The gate assembly of claim 2 in which the means securing the lower end portion of the upper spring and the upper end portion of the lower spring to the tubular upright, comprise:
a spring-retaining structure located between the upper and lower springs within the tubular upright, the spring-retaining structure comprising anupper end portion engaging the lower end portion of the upper spring and a lower end portion engaging the upper end portion of the lower spring;
a passage formed in the spring-retaining structure;
a passage formed in the tubular upright and aligned with the passage in the spring-retaining structure; and, a retaining element extending through the aligned passages.

4 . The gate assembly of claim 3 in which:
the body portion of each of the caps comprises a slot shaped to receive the spring end portion engaged by the body portion and to permit relative axial displacement of the received spring end portion;
each of the upper and lower end portions of the spring-retaining structure comprises a slot shaped to receive the spring end portion engaged by the end portion of the spring-retaining structure and to permit relative axial displacement of the spring end portion engaged by the end portion of the spring-retaining structure;
the slots of the caps and of the spring-retaining structure are spaced to permit lengthwise expansion and contraction of each of the springs in response to gate rotation relative to the support.

5. The gate assembly of claim 1 in which the upper and lower springs are wound in a common direction.

6. The gate assembly of claim 1 in which:
the support structure comprises an upper bracket which defines an upper opening, a lower bracket which defines a lower opening, and the upper and lower openings are vertically aligned;
the upper and lower ends of the tubular structure are mounted respectively in the upper and lower openings defined by the brackets; and, the upper and lower rotary elements are caps, the upper cap comprises a head portion that seats against the upper bracket and a body portion that extends downward into the upper end of the tubular member and engages the upper end portion of the upper spring, and the lower cap comprises a head portion that seats against the lower bracket and a body portion that extends upward into the upper end of the tubular member and engages the lower end portion of the lower spring.

7. The gate assembly of claim 6 in which the upper and lower end caps are secured to the brackets with bolts.

8. A gate assembly comprising:
a support including upper and lower brackets, each of the brackets being formed with an aperture, the apertures of the brackets being vertically aligned;

a gate including a tubular upright with upper and lower open ends mounted within the apertures of the upper and lower brackets, the gate being supported by the support for rotation about a rotational axis extending vertically through the tubular upright;
upper and lower coil spring located within the tubular upright in alignment with the rotational axis, each of the springs having an upper end portion and a lower end portion, the springs being wound in the same direction;
upper and lower end caps, the upper end cap comprising a head portion that seats against the upper bracket and a body portion that extends downward into the upper end of the tubular upright and secures the upper end portion of the upper spring to the upper cap for rotation therewith, the lower end cap comprising a head portion that seats against the lower bracket and a body portion that extends upward into the lower end of the tubular upright and secures the lower end portion of the lower spring to the lower cap for rotation therewith; and, means for securing the lower end portion of the upper spring and the upper end portion of the lower spring to the tubular upright, the securing means comprising a spring-retaining structure located between the upper and lower springs within the tubular upright, a passage formed in the spring-retaining structure, a passage formed in the tubular upright and aligned with the passage in the spring-retaining structure, and a retaining element extending through the aligned passages; and, means releasably fastening the upper and lower end caps respectively to the upper and lower bracket.