The present invention relates to an apparatus for adjusting the installation height of a concrete floor joint system.

Floor joint systems comprising divider plates, load transfer dowelling and arris protection are well known in the construction of concrete floors. An example of a known system is given in EP 1 123 443. It is common when

installing such floor joint systems to use height adjustment apparatus which can be temporarily attached to the floor joint system to allow height adjustment before the concrete is poured. The height adjustment apparatus can then be removed once the concrete has set.

Various height adjustment systems are known. One such system, disclosed in EP 1 389 648, comprises an angled bracket which supports a screw threaded rod to which is attached a height adjustment arm. In use, the height adjustment arm attaches to the upper arris rail of a floor joint system to allow height adjustment by moving the height adjustment arm along the screw threaded rod. A disadvantage of this arrangement is that the angled bracket protrudes above the height of the finished concrete floor slab and this can interfere with power trowelling and levelling processes which are necessary to complete the floor laying process. In certain circumstances power trowelling

equipment can collide with the height adjustment brackets and cause catastrophic safety failures. Another height adjustment device made available by Metalscreed of Unit 70, City Business Park, Plymouth, Devon, PL3 4BB, comprises a clamp which is attached to a screw threaded rod for height adjustment. In use the clamp attaches to the underside of a lip of the arris rail of a floor joint system. The height is adjusted by means of the screw threaded rod. A disadvantage of this system is that the height adjustment is provided by a pivoted arm which necessarily introduces lateral movement as the height is adjusted.

An additional problem of both of the above mentioned systems is that they only provide support at the top and bottom of the floor joint system. It is well known in the art that floor joint systems can deflect under the

hydrostatic pressure of liquid concrete resulting in

misalignment of the dowelling apparatus. Both of the height adjustment systems mentioned above therefore require

substantial additional bracing with wooden blocks, metal pins or similar to prevent this.

In a first aspect the present invention provides a combination of a floor joint system and a scissor lift, the scissor lift comprising upper and lower lift members

moveably connected together by first and second pivotable height adjustment arms, wherein the scissor lift is

connectable to the floor joint system to allow adjustment of the height of the floor joint system, and wherein the scissor lift is arranged to provide lateral support to the floor joint system in use at an intermediate position between an upper and lower extremity of the floor joint system . The present invention is advantageous as the scissor lift provides lateral support to the floor joint system in use between the top and bottom of the floor joint system thus helping to prevent, or minimise, lateral deflection under the hydrostatic pressure of liquid concrete.

The scissor lift is preferably arranged to support a laterally projecting load transfer member, such as a dowel plate, of the floor joint system. This provides a

convenient way of providing lateral support to the floor joint system at an intermediate point by utilising existing components of the floor joint system. In a preferred example the scissor lift comprises a support arm pivotally connected to the first height

adjustment arm and supported by a linkage arm, the linkage arm being pivotally connected to the second height

adjustment arm, wherein a distal end of the support arm is arranged to provide the lateral support to the floor joint system in use at an intermediate position between an upper and lower extremity of the floor joint system. This arrangement allows the floor joint system to be laterally supported between the top and bottom of the floor joint system without needing to rely on existing components of the floor joint system. This allows greater flexibility in the positioning of the scissor lift in use.

The linkage arm is preferably pivotally connected to the support arm so that the linkage arm moves with the support arm and does not need to be separately positioned In a preferred example a distal end of the linkage arm is arranged to provide lateral support to the floor joint system in use at an intermediate position between an upper and lower extremity of the floor joint system such that the linkage arm is a second support arm which provides

additional support to the floor joint system.

In another preferred example the scissor lift further comprises a second support arm pivotally connected to the second height adjustment arm and supported by a second linkage arm, the second linkage arm being pivotally

connected to the first height adjustment arm, wherein a distal end of the second support arm is arranged to provide lateral support to the floor joint system in use at an intermediate position between an upper and lower extremity of the floor joint system. This arrangement allows for additional support of the floor joint system which may be at the same intermediate point as the first support arm, or at a different intermediate point.

Preferably the, or each, support arm is arranged to support a divider plate of the floor joint system in use. This is advantageous as it is the divider plate of the floor joint system which experiences the most deflection.

Movement of the distal end of the, or each, support arm is preferably substantially constrained to a plane which is substantially parallel to the major plane of the floor joint system in use. This allows the distal end of the, or each, support member to remain at a consistent distance from the floor joint system regardless of the separation between the upper and lower lift members. Advantageously, the plane of movement of the distal end of the, or each, support member can be set to coincide with the divider plate of the floor joint system such that it is the divider plate which is supported regardless of the separation between the upper and lower lift members.

In a second aspect the present invention provides a scissor lift for adjusting the height of a floor joint system, comprising upper and lower lift members moveably connected together by first and second pivotable height adjustment arms; a connector for releaseably connecting the scissor lift to a floor joint system to allow adjustment of the height of the floor joint system; and a support member for providing lateral support to the floor joint system in use at an intermediate position between an upper and lower extremity of the floor joint system.

The scissor lift of this second aspect of the present invention is advantageous as it may be used with different types of floor joint system to provide height adjustment and lateral support without having to provide additional

components or bracing.

Preferably the support member comprises a support arm pivotally connected to the first height adjustment arm and supported by a linkage arm, the linkage arm being pivotally connected to the second height adjustment arm, wherein a distal end of the support arm is arranged to provide the lateral support to the floor joint system in use at an intermediate position between an upper and lower extremity of the floor joint system. This arrangement allows the floor joint system to be laterally supported between the top and bottom of the floor joint system without needing to rely on existing components of the floor joint system. This allows greater flexibility in the positioning of the scissor lift.

In a preferred example the linkage arm is pivotally connected to the support arm so that it moves with the support arm and does not have to be separately positioned. A distal end of the linkage arm is preferably arranged to provide lateral support to the floor joint system in use at an intermediate position between an upper and lower extremity of the floor joint system such that the linkage arm is a second support arm which provides additional support to the floor joint system.

In another preferred example the scissor lift further comprises a second support arm pivotally connected to the second height adjustment arm and supported by a second linkage arm, the second linkage arm being pivotally

connected to the first height adjustment arm, wherein a distal end of the second support arm is arranged to provide lateral support to the floor joint system in use at an intermediate position between an upper and lower extremity of the floor joint system. This arrangement allows for additional support of the floor joint system which may be at the same intermediate point as the first support arm, or at a different intermediate point. The scissor lift preferably further comprises a height adjustor which is arranged to act on at least one of the height adjustment arms to adjust the relative separation between the upper and lower lift members. This provides a convenient means of adjusting the height of the scissor lift and thus the height of the floor joint system. In a preferred example the scissor lift further comprises an anchor point slideably connected to the lower lift member. This allows the scissor lift to be anchored to the floor for greater stability whilst allowing movement of the scissor lift towards and away from the floor joint system if lateral adjustment is needed.

The connector of the scissor lift is preferably

arranged to be connected to an arris rail of a floor joint system which provides a convenient attachment point.

Examples of apparatus according to the present

invention will now be described with reference to the following Figures in which: Figure 1 shows a side view of a scissor lift according to the present invention at its lowest height setting;

Figure 2 shows the scissor lift of Figure 1 in a first raised position;

Figure 3 shows the scissor lift of Figure 1 in a second raised position attached to a floor joint system.

Figure 4 shows a side view of a second scissor lift according to the present invention; Figure 5 shows an adaptation of the scissor lift of Figure 4 ;

Figure 6 shows another adaptation of the scissor lift of Figure 4 ;

Figure 7 shows a side view of a third scissor lift according to the present invention; and Figure 8 shows a side view of a fourth scissor lift according to the present invention attached to a floor joint system .

Referring to Figure 1, the scissor lift 10 comprises a lower lift member 20 and an upper lift member 21. The lower lift member 20 has an inverted T cross-section (not shown) to provide floor support and the upper lift member 21 has a right T cross-section (not shown) . The lower and upper lift members 20, 21 are moveably connected with respect to one another by first and second pivotable height adjustment arms 30, 31 described in greater detail below.

The lower lift member 20 extends from a first end 24 to a second end 28 and comprises first and second adjustment slots 22, 70. The second adjustment slot 70 is located proximate the second end 28 of the lower lift member 20 and the first adjustment slot 22 is located between the first end 24 of the lower lift member 20 and the second adjustment slot 70. The upper lift member 21 extends from a first end 25 to a second end 26 and comprises a third adjustment slot 23 located proximate the second end 26 of the upper lift member 21. As shown in Figure 1, the first adjustment slot 22 and the third adjustment slot 23 are of substantially the same length and located in substantial vertical alignment with one another. The lower lift member 20 further comprises a support angle 90 attached to the first end 24 of the lower lift member 20 to provide additional floor support. The upper lift member 21 comprises a dowel 60 attached to the

underside of the upper lift member 21 at the first end 25 of the upper lift member. The dowel 60 protrudes past the first end 25 of the upper lift member 21.

The first and second height adjustment arms 30, 31 are pivotally connected together by a bolt 36 located

substantially at the mid-point of the height adjustment arms. The bolt 36 carries a pin 80 which limits the

movement of the lower and upper lift members 20, 21 towards one another. A first end 37 of the first height adjustment arm 30 is pivotally connected proximate the first end 24 of the lower lift member 20 by a bolt 32, and a second end 38 of the first height adjustment arm 30 is pivotally and slideably connected to the upper lift member 21 by a bolt 34 which engages with the third adjustment slot 23. Similarly, a first end (not shown) of the second height adjustment arm 31 is pivotally connected proximate the first end 25 of the upper lift member 21 by a bolt 33, and a second end 39 of the second height adjustment arm 31 is pivotally and

slideably connected to the lower lift member 20 by a bolt 35 which engages with the first adjustment slot 22.

The height adjustment apparatus 10 further comprises first and second support arms 40, 41. The first support arm 40 extends between a first end 45 and a second end 46 and the second support arm 41 extends between a first end 47 and a second end (not shown) . The first support arm 40 is pivotally connected to the first height adjustment arm 30 proximate its second end 46 by a pin 43, and the second support arm 41 is pivotally connected to the second height adjustment arm 31 proximate its second end by a pin 44. The pins 43, 44 are each located substantially mid-way between the first ends of the respective height adjustment arms and the bolt 36. The support arms 40, 41 are pivotally

connected to one another by a pin 42 located towards the first ends 45, 47 of the support arms. The first ends 45, 47 of the support arms 40, 41 are the distal ends of the support arms .

A adjustment screw 50 is provided as a height adjustor to facilitate height adjustment of the scissor lift 10. The adjustment screw 50 passes through a flange 27 at the second end 26 of the upper lift member 21 and abuts the second end 38 of the first height adjustment arm 30. The adjustment screw 50 is held in place by a nut 52. A locking nut or pin (not shown) may be provided to lock the adjustor screw 50 in position during use. An anchor point 71 is slideably connected to the lower lift member 20 by a bolt 72 with engages with the second adjustment slot 70. The anchor point 71 may be attached to the floor in use to provide additional floor support and adj ustment .

As shown in Figure 2, when the adjustment screw 50 has been screwed towards the first end 25 of the upper lift member 21 the second end 38 of the first height adjustment arm 30 moves towards the first end 25 of the upper lift member 21, the bolt 34 pivoting and sliding to accommodate this movement. This in turn causes the first and second height adjustment arms 30, 31 to separate such that the bolt 35 pivots and slides towards the first end 24 of the lower lift member 20. At the same time the first and second support arms 40, 41 separate and the distance between the lower and upper lift members 20, 21 increases.

Figure 3 shows the height adjustment apparatus 10 in use with a floor joint system 100. The floor joint system comprises a divider plate 130 formed of upper and lower divider plates 131a, 131b. Dowel plates 120 are attached between the divider plates 131a, 131b. Dowel sleeves 125 cover the dowel plates 120 on one side of the divider plate 130. A first arris rail 114a is attached to the top of the divider plate 131a and a second arris rail 114b is attached to the first arris rail 114a by shearable bolts 140. The arris rails each carry anchor pins 110.

The height adjustment apparatus 10 is removeably attached to the first arris rail 114a by dowel 60 which fits into a hole (not shown) in the arris rail. Thus, the height of the floor joint system 100 may be adjusted by adjusting the separation of the lower and upper lift members 20, 21 of the scissor lift 10 by means of the adjustment screw 50.

As shown, the first, or distal, ends 45, 47 of the first and second support arms 40, 41 are located proximate the divider plate 130 in use. The first and second support arms 40, 41 are therefore positioned to provide lateral support to the floor joint system 100 to help prevent the floor joint system deflecting under the hydrostatic pressure of liquid concrete. In this example the distal ends 45, 47 of the support arms 40, 41 will move towards and away from the floor joint system 100 by a small amount depending on the separation between the lower and upper lift members 20, 21. The floor joint system may therefore need to deflect somewhat in order to come into contact with the support arms. Nevertheless, the support arms 40, 41 are positioned to provide lateral support to the floor joint system in use such that lateral deflection of the floor joint system 100 is less than it would be if the support arms were not present thus removing the need for additional support or bracing. In the particular configuration shown in Figure 3 the distal ends 45, 47 of the support arms contact the divider plate 130 so that no deflection of the divider plate is necessary.

The lateral position of the scissor lift 10 with respect to the floor joint system 100 may be varied by adjustment of the bolt 72 in the second slot 70 (see Figure 1) when the anchor point 71 is anchored to the floor for additional support. In an alternative example (not shown) the scissor lift

10 may attach to the floor joint system by any suitable means including a clamp or clip arrangement. In addition, the adjustment screw 50 may be replaced by any other

suitable means of adjusting the relative position of the height adjustment arms 30, 31, for example, a scissor mechanism which attaches to the height adjustment arms 30, 31 between the bolt 36 and the second ends of the height adjustment arms 38, 39. In addition, the height adjustment means may be powered by hydraulic, electric or any other suitable means . A second example of a scissor lift 200 is shown

schematically in Figure 4. Where appropriate like reference numerals have been used to identify like features to those described above with respect to Figures 1 to 3. In Figure 4 first and second support arms 240, 241 of equal length are pivotally attached to the first and second height adjustment arms 30, 31 respectively by pins 44, 43 which are located mid way between the first ends 37, 37a of the first and second height adjustment arms 30, 31 and the bolt 36. The first and second support arms 40, 41 are pivotally connected to one another by a pin 42 who's

midpoint is located on a vertical line 201 joining the centre points of bolts 32, 33. The distal ends 245, 247 of the first and second support arms 240, 241 are semi-circular and have a radius (r) from the midpoint of pin 42 which is equal to the distance (d) between the centre points of the bolts 33, 32 and the first and second ends 24, 25 of the lower and upper lift members 20, 21. This arrangement allows the pin 42 to remain on the line 201 regardless of the separation between the lower and upper lift members 20, 21. Since the radius (r) is equal to the distance (d) , the distal ends 245, 247 of the first and second support members 240, 241 remain in line with the first ends 24, 25 of the lower and upper lift members 20, 21.

The line 201 is arranged to be in a plane which is substantially parallel to the plane of the divider plate 130 of the floor joint system 100 in use. The plane of the divider plate 130 being the major plane of the floor joint system. In this way the distance between the distal ends 245, 247 of the first and second support arms 240, 241 and the divider plate 130 remains substantially constant

regardless of the separation between the lower and upper lift members 20, 21.

If the radius (r) is selected to be substantially the same as the distance between the line 201 and the plane of the divider plate 130 in use, the distal ends of the support arms can be arranged to be in contact with the divider plate at all height settings of the scissor lift . Such an

arrangement is shown in Figure 5 where line 202 represents the major plane of the divider plate of a floor joint system in use .

Figure 6 shows a modification of the scissor lift of Figure 4. Where appropriate like reference numerals have been used to identify like features.

The scissor lift 300 shown in Figure 6 comprises a support bar 310 which is pivotally attached to the first and second support arms 240, 241 by pin 42, and to the first and second height adjustment arms 30, 31 by bolt 36. The support bar 310 comprises a slot 311 which allows the support bar 310 to slide along the bolt 36 as the distance between the lower and upper lift members 20, 21 varies. The distal ends 312, 313 of the support bar 310 are at a distance (d) from the line 201 joining the centre points of the bolts 32, 33 and the pin 42, such that the distal ends 312, 313 of the support bar 310 lie on line 202 which coincides with the plane of the divider plate of a floor joint system in use. In this way, the support bar 310 provides support to the divider plate in use regardless of the separation between the lower and upper lift members 20, 21. the bolt 36 may be provided with a lock member to prevent movement of the support bar 310 in use.

Figure 7 shows an alternative scissor lift 400. Where appropriate like reference numerals have been used to identify like features.

The scissor lift 400 comprises first and second support arms 440, 441 which are pivotally connected to the first and height adjustment arms 30, 31 respectively by pins 43, 44. The scissor lift 400 further comprises first and second linkage arms 460, 461 which are pivotally connected to the second and first height adjustment arms 31, 30 respectively by pins 465, 466. The first linkage arm 460 is pivotally connected to the first support arm 440 by pin 467, and the second linkage arm 461 is pivotally connected to the second support arm 441 by pin 468.

The distal ends 445, 447 of the first and second support arms 440, 441 are positioned to provide lateral support to a floor joint system in use at two positions between the upper and lower extremities of the floor joint system . In addition to providing lateral support, the support arms of the above described embodiments help to prevent vertical misalignment of the upper and lower lift members 21, 20 since the support arms together with the height adjustment arms form a pantograph type arrangement which substantially constrains movement of the upper lift member 21 with respect to the lower lift member 20 to a single vertical plane. This helps to prevent longitudinal

misalignment of the floor joint system 100. In the case of Figure 7, it is the support arms and the linkage arms which provide two pantograph type arrangements together with the height adjustment arms.

Figure 8 shows an alternative scissor lift 500. Where appropriate like reference numerals have been used to identify like features. The scissor lift 500 of Figure 8 comprises a support member 510 which is pivotally connected to the first and second height adjustment arms 30, 31 at bolt 36. The support member 510 comprises jaws 511 which engage with the dowel plate 120 of the floor joint system in use to provide lateral support to the floor joint system via the dowel plate .

The scissor lift 500 also comprises first and second linkage arms 540, 541 which are pivotally connected to the first and second height adjustment arms 30, 31 by pins 543, 544. The linkage arms 540, 541 are pivotally connected to one another by pin 542. The linkage arms 540, 541 help to prevent vertical misalignment of the upper and lower lift members 21, 20 since the linkage arms 540, 541 together with the height adjustment arms 30, 31 form a pantograph type arrangement which substantially constrains movement of the upper lift member 21 with respect to the lower lift member 20 to a single vertical plane. The linkage arms 540, 541 may also be used to adjust the height of the scissor lift, for example, by providing a locking bolt in place of the pin 542.