AU714004B2

AU714004B2 - Actuation means

Info

Publication number: AU714004B2
Application number: AU92418/98A
Authority: AU
Inventors: Pirrie Sargent
Original assignee: PIRRELLA HOLDINGS Pty Ltd
Current assignee: PIRRELLA HOLDINGS Pty Ltd
Priority date: 1998-05-13
Filing date: 1998-11-18
Publication date: 1999-12-16
Anticipated expiration: 2018-05-13
Also published as: AU695644B3; AU9241898A

Description

1 ACTUATION

MEANS

This invention relates to actuation means.

This invention has particular but not exclusive application to actuation means for urging apart and/or drawing together opposing sets of legs of a step ladder, and for illustrative purposes reference shall be made to said application. However this invention may be used in other applications where one member is capable of pivotal movement relative to another member and it is desirous to have means of actuating said movement which does not involve the placement of body parts such has a hand intermediate the two members. For example, the actuation means may be used to 00 move the leg of a folding table between an operative or 699000 S0 extended position and an inoperative or folded position. The 0000 00 5 actuation means may also be used to "collapse" foldable 00 articles such as prams or the like.

Most step ladders include a pair of opposing rails interconnected by a plurality of intermediate members, rungs 9 0 or steps spaced at regular intervals along the length 20 thereof. Typically step ladders also include a pair of ooo spaced supporting members or legs which are capable of pivotal movement relative to an upper portion of the step ladder and are arranged such that they move in unison.

S. Some step ladders include locking means for locking the supporting members in an operative supporting position such as an over centre linkage.

2 By "breaking" the linkage, users may urge the rails and the supporting members together, which they may desire to do for storage purposes. However the scissor like action of the collapsing linkage has been known to injure fingers inadvertantly caught therebetween, having previously been used to "break" the operatively extended links.

The present invention aims to alleviate at least one of the aforementioned disadvantages and to provide actuation means which will be reliable and efficient in use.

With the foregoing and other objects in view this invention in one aspect relates to actuation means for selectively urging apart or drawing together a first member .0 o which is capable of pivotal movement relative to a second member, said actuation means including: 15 an over centre linkage consisting of a first link having a first end portion and an opposing second end portion, said second end portion being pivotally connected to a first end portion of a second link which includes an opposing second end portion which is pivotally connected to the second member, said first end portion of said first link being o0 0: pivotally connected to the first member; limiting means on either said first link or said second link which is adapted to engage the other of said first or second link so as to inhibit movement of said links which would have a tendency to draw the two members together, and a handle attached to said first link for pivoting said -C~~rx 3 first link about the pivotal connection between said first link and the first member, said handle extending away from the first member in a direction opposite to that of said second end portion of said first link.

The first and second links are preferably of rigid or semi rigid construction and may be constructed from any suitable material such as a variety of wood, metal or plastics materials. The links also may take any suitable shape,- For example, in one embodiment the links may be elongate strips of metal. However, in other embodiments the links may be constructed from bar stock such as bar stock having a round or rectangular transverse cross-section.

The limiting means may include a stop such as a projection extending outwardly from a face or edge of either the first or second links which is adapted to engage the other link.

The handle, in one embodiment, may form an integral part of the first link. However in other embodiments the handle may be either permanently or releasably attached to the first link. For example, the handle may be attached to the first link in a manner which allows the handle to be folded against the first member or the first link when not required, such as for storage purposes.

Preferably the weight of the handle is such that in use the gravitational forces acting thereon are not sufficient to overcome the forces applied by the links to the members so as

II

4 to maintain said members apart.

In anther aspect, this invention relates to a ladder, said ladder including: a pair of opposing rails interconnected by a plurality of intermediate members spaced at regular intervals along the length thereof; a pair of spaced supporting members or legs which pivot in unison relative to respective upper portions of said rails,-- said supporting members being moveable between .a first or folded position wherein said supporting members each lie adjacent to a respective rail and a second or extended position wherein said supporting members support said rails in a free upstanding position; an over centre linkage consisting of a first link and a .;15 second link interconnecting one of said rails and an adjacent one of said support members, said first link having a first end portion and an opposing second end portion, said second end portion being pivotally connected to a first end portion of said second link which includes an opposing second end portion which is pivotally connected to either the aforesaid rail or supporting member, said first end portion of said first link being pivotally connected to the other of said rail or supporting member; limiting means on either said first link or said second link which is adapted to engage the other of said first or second link so as to inhibit movement of said links which would have a tendency to draw together said rails and said supporting members, and a handle attached to said first link for pivoting said first link about the pivotal connection between said first link and either said rail or said supporting member, said handle extending away from said rail or said supporting member in a direction opposite to that of said second end portion of said first link.

In one embodiment, the handle may simply include a portion of the first end portion of the first link such as the portion to one side of the pivotal connection connecting said link to either said rail or said supporting member.

In some embodiments there may be provided two pairs of linkages each interconnecting a respective rail and an adjacent supporting member and wherein there may be provided two handles, each attached to a respective first link. The handles may be interconnected by an intermediate member and wherein use movement of the two handles may be effected by moving the intermediate member.

The handle, or handles may be releasably connected to the first link thereby enabling easy conversion of existing ladders as well as providing users with the option of choosing whether to connect the handle(s) or not.

In order that this invention may be more easily understood and put into practical effect, reference will now be made to the accompanying drawings which illustrate a preferred embodiment of the invention and wherein:- FIG. 1 is a perspective view of a ladder constructed in accordance with the present invention; FIG. 2 is a side view of the ladder illustrated in figure 1, the ladder being shown in a partially collapsed or folded state; FIG. 3 is another side view of the ladder illustrated in figure 1, the ladder being shown in a collapsed of folded state; 1 0 FIG. 4 is a detailed side view of the actuation means of the ladder illustrated in figure 1; FIG. 4a is a cross-sectional end view of the actuation means; FIG. 5 is a plan view of parts of a handle assembly 15 constructed in accordance with the present invention; FIG. 5a is a perspective view of another ladder and the detachable handle assembly illustrated in figure FIG. 6 is a side view of a portion of the actuation means of the ladder illustrated in figure 0 7 FIG. 7 is a cross-sectional end view of the actuation means illustrated in figure 6, and FIG. 8 is a second cross-sectional end view of the actuation means illustrated in figure 6.

Figures 1 to 4 illustrate a ladder 10 which includes a pair of opposing rails 11 which are interconnected by a plurality of intermediate members, rungs or steps 12 that are spaced at regular intervals along the length of said rails.

The ladder 10 also includes a pair of spaced supporting members or legs 13 which pivot in unison relative to respective upper portions 14 of the rails 11.

The legs 13 are capable of movement between a first or collapsed position whereby they lie substantially parallel to an adjacent rail 11, as illustrated in figure 4, and a second or fully extended position whereby the legs and the adjacent rails~are divergent, as illustrated in figure 1. When the legs 13 are fully extended they may be used to support the ladder 10 in an upstanding position as illustrated in figure 9 090*,

B

B s 9*Ore* 0, 9S*S

B

0*r The ladder 10 also includes actuation means 15 which may be used to selectively move the legs 13 relative to the rails 11 and to lock the legs 13 in a fully extended position relative to the rails 11. The actuation means 15 includes two over centre linkages each consisting of a first link 16 and a second link 17 which interconnect a respective rail 11 and an adjacent leg 13. The first link 16 includes a first end portion 18 and an opposing second end portion 19, the second end portion 19 being pivotally connected at 20 to a first end portion 21 of the second link 17. The second link 17 includes an opposing second end portion 22 which is pivotally connected at 23 to a rail 11. The first end portion 18 of the first link 16 is pivotally connected to an adjacent leg 13 at 24.

8 The second link 17 also includes limiting means which is adapted to engage the first link 16 s0 as to inhibit movement of said linkages which in use would have a tendency to draw the rails and the legs together. The limiting means includes a flange 25 which extends outwardly from the second link 17 and which is adapted to engage the upper edge 26 of the first link 16.

When the legs 13 are fully extended, as illustrated in figure-. 1, further downward movement of the pivot connection 20 and the corresponding tendency for the legs 13 to move towards the rails 11 is inhibited by the engagement of the flange 25 which abuts/rests upon the upper edge 26 of the first link 16, as shown in figure 4a. It is also noted that when the flange 25 abuts/rests upon the upper edge 26, the pivot connection 20 lies below a line containing pivot connections 23 and 24.

C. 0The actuation means also includes a handle 27 which in the embodiment illustrated in figures 1 to 4 consists of the CeCCpart of the first end portion 18 which extends away from the pivot 24 in a direction opposite to the second end portion 19. The hnls27 of the two over centre linkages are CCCCCW interconnected by an intermediate member/handle 28.

In use, the legs 13, which are folded against the rails C C 11, may be placed in a supporting or extended position by urging the rails 11 and the legs 13 apart adsac sufficient that further rotation of the links 16 and 17 is

I

9 prevented by engagement of flange 25 and the upper edge 26.

When the ladder is no longer required, it may be folded up for transportation and or storage purposes such that the legs 13 lie substantially parallel to the rails 11 as shown in figure 4. This may be achieved by pushing generally downwardly on the handle 28 which will cause the links 16 and 17 to "break" and the pivot connection 20 to move upwardly thereby drawing the legs 13 towards the rails 11.

Figure 5a shows a typical step ladder 110 which includes a pair of opposing rails 111 which are interconnected by a plurality of intermediate members, rungs or steps 112 that are spaced at regular intervals along the length of said rails. The ladder 10 also includes a pair of spaced 0 supporting members or legs 113 which pivot in unison relative 15 to respective upper portions 114 of the rails 111.

a The legs 113 are capable of movement between a first or collapsed position whereby they lie substantially parallel to an adjacent rail 111 and a second or fully extended position whereby the legs and the adjacent rails are divergent, as illustrated in figure 5a. When the legs 113 are fully extended they may be used to support the ladder 110 in an upstanding position as illustrated in figure

S

The ladder 110 also includes actuation means 115 which e*e a may be used to selectively move the legs 113 relative to the rails 111 and to lock the legs 113 in a fully extended position relative to the rails 111. The actuation means 115 includes two over centre linkages each consisting of a first link 116 and a second link 117 which interconnect a respective rail 111 and an adjacent leg 113. The first link 116 includes a first end portion 118 and an opposing second end portion 119, the second end portion 119 being pivotally connected at 120 to a first end portion 121 of the second link 117. The second link 117 includes an opposing second end portion 122 which is pivotally connected at 123 to a rail 111. -The first end portion 118 of the first link 116 is pivotally connected to an adjacent leg 113 at 124.

The second link 117 also includes limiting means which is adapted to engage the first link 116 so as to inhibit movement of said linkages which in use would have a tendency to draw the rails and the legs together. The limiting means includes a flange 125 which extends outwardly from the second 4..4 link 117 and which is adapted to engage the upper edge 126 of the first link 116.

When the legs 113 are fully extended, as illustrated in figure 5a, further downward movement of the pivot connection 120 and the corresponding tendency for the legs 113 to move cSJO• 4 towards the rails 111 is inhibited by the engagement of the flange 125 which abuts/rests upon the upper edge 126 of the first link 116. It is also noted that when the flange 125 abuts/rests upon the upper edge 126, the pivot connection 120 lies below a line containing pivot connections 123 and 124.

Figure 5 shows parts of a handle assembly including a 11 handle 145 constructed from a strip of metal and wherein the opposing end portions are each provided with a mounting flange 146. The handle assembly also includes two struts 150, each having a respective end portion 151 which is connectable to a respective flange 146, such as may be achieved using a rivet or a nut and bolt.

In one embodiment, the opposing free end portions 152 of the two opposing struts may be each attached to a respective first-link 116 along its length such that each strut forms an extension of said link. For example, two or more rivets 153 may be used to secure each strut 150 to a respective link 116. However, in other embodiments one or more clips 155 may be used to releasably secure the struts 150 to the links 9 116, as illustrated in figures 6 and 8. Thus, the benefits ,15 of the present invention may be achieved by connecting the S. handle 145 and the two struts 150 two the existing linkages of existing step ladders.

In use, the legs 113, which are folded against the rails I11, may be placed in a supporting or extended position by urging the rails 111 and the legs 113 apart a distance sufficient that further rotation of the links 116 and 117 is prevented by engagement of flange 125 and the upper edge 126.

When the ladder is no longer required, it may be folded up for transportation and or storage purposes such that the legs 113 lie substantially parallel to the rails iii. This may be achieved by pushing generally downwardly on the handle 12 145 which will cause the links 116 and 117 to "break" and the pivot connection 120 to move upwardly thereby drawing the legs 113 towards the rails 111.

It will be appreciated that the handle(s) may be used to collapse the legs of the ladder without the user having to place their hand between the legs and the rails of the ladder or between the first and second links connecting same.

It will of course be realised that the above has been given-only by way of illustrative example of the invention and that all such modifications and variations thereto as would be apparent to persons skilled in the art are deemed to fall within the broad scope and ambit of the invention as is herein defined in the appended claims.

e 6' v a G •8 09 *0 *0 4 a

Claims

1. A ladder including:- a pair of opposing rails interconnected by a plurality of intermediate members spaced at regular intervals along the length thereof; a pair of spaced supporting members or legs which pivot in unison relative to respective upper portions of said rails, said supporting members being moveable between a first or folded position wherein said supporting members each lie adjacent to a respective rail and a second or extended position wherein said supporting members support said rails .o in a free upstanding position; an over centre linkage consisting of a first link and a second link interconnecting one of said rails and an adjacent one of said support members, said first link having a first end portion and an opposing second end portion, said second S S end portion being pivotally connected to a first end portion of said second link which includes an opposing second end portion which is pivotally connected to either the aforesaid rail or supporting member, said first end portion of said first link being pivotally connected to the other of said rail or supporting member; limiting means on either said first link or said second link which is adapted to engage the other of said first or second link so as to inhibit movement of said links which would have a tendency to draw together said rails and said 14 supporting members, and a handle attached to said first link for pivoting said first link about the pivotal connection between said first link and either said rail or said supporting member, said handle extending away from said rail or said supporting member in a direction opposite to that of said second end portion of said first link.

2. K-ladder as claimed in claim 1, wherein there is S* provided two pairs of linkages each interconnecting a 10 respective rail and.an adjacent supporting member and wherein there is provided two handles, each attached to a respective .0 first link, said handles being interconnected by an intermediate member such that the move in unison.

3. A ladder as claimed in claim 1 or claim 2, wherein said :15 handles are each affixed to a respective first link using a fastener. DATED THIS SEVENTEENTH DAY OF NOVEMBER,

1998. PIRRELLA HOLDINGS PTY LTD BY THEIR ATTORNEYS PIZZEYS PATENT TRADE MARK ATTORNEYS 2 0 P I Z Z E Y S PATENT TRADE MARK ATTORNEYS