Jointing tool

Abstract

The joining tool is used for profiling a compound in a joint between two adjacent paving units, construction blocks, tiles or the lie. The joining tool comprises a head 12 having an underside 20 with

Description

The present invention is concerned with dressing of joints such as the joints between adjacent slabs in a patio. There are a variety of different forms of paving that use multiple tessellating paving units such as tiles or slabs to cover an area of ground, between which are narrow spaces filled by a compound which is inserted between the paving units and then sets in position to form a joint. This joint serves both aesthetic and functional purposes. The joint helps to lockthe paving units in place, resisting any tendency forthem to move or rock, and resists undermining of the slab’s foundation by ingress of rainwater as well as resisting growth of weeds and moss between slabs and collection of waste material. But it also gives the paving a more attractive finished appearance. Traditionally the compound used for jointing is a mortar made from cement, sharp sand and water, often with certain additives to improve the mortar’s material properties. Traditional mortar is often manually inserted into joints with a trowel. It is also known to use more modern polymeric resin-based jointing compounds, which offer various advantages. These may comprise a two-part resin-and-hardener mix such as an epoxy resin, or a single part resin system. In either case they typically comprise an admixture of sand or some other particulate material. Resin-based jointing compounds are often spread over the surface of the pavingto fill the joints, e.g. using a broom or long-handled squeegee and then removed from the paving’s upper face before setting. This process can be relatively rapid and convenient. It is a common practice to shape the exposed upper surface of the jointing compound after its insertion into the joint to form a chosen profile. For this purpose, a jointing tool is run along the joint manually, imprinting the profile into the joint’s upper surface. Commonly the profile is a shallow, upwardly concave curve. Other profiles are known, such as a flat recessed joint or a flush joint. The jointing tool is typically a small handheld item with an elongate head part whose underside has the desired profile. Some jointing tools have a handle coupled to the head through a short inclined neck portion. Jointing tools came in a range of shapes and sizes, to provide a range of different profiles. The user of a conventional jointing tool typically needs to get down on their knees to apply it to the joint. This can be highly onerous and can even cause strains and other injuries, especially where large areas of paving are involved. Paving joints typically fail overtime. Limiting factors in their efficacy and lifetime include the intimacy of the physical engagement of the compound with the slabs, the presence of air gaps in the compound, the depth of penetration of the compound between the slabs, and the consistency, density and consequent strength and durability of the compound itself. While the explanation above refers to paving used for ground cover, there are other situations in which joints between adjacent units need to be profiled. Examples include the grouting between adjacent wall tiles or other wall-covering elements, and the mortar in masonry walls built e.g. from construction blocks such as house bricks or concrete masonry units. The present invention is applicable to these examples as well. In accordance with the present invention, there is jointing tool for profiling a compound in a joint between two adjacent paving units, construction blocks, tiles or the like, the jointing tool comprising a head having an underside with a profile to be moved along the joint, thereby imparting a complementary profile to the compound in the joint, and a vibration mechanism for causingthe head to vibrate in use. In accordance with a second aspect of the present invention, there is a method of profiling a compound in a space between two adjacent two adjacent paving units, construction blocks, tiles or the like, the method comprising drawing a profiled underside of a head of jointing tool along the joint to impart a predetermined profile to the compound whilst the head of the jointing tool is driven to vibrate. A specific embodiment of the present invention will now be described, byway of example only, with reference to the accompanying drawing (Figure 1), which is a side view of a jointing tool embodying the present invention. The illustrated jointing tool 10 is intended for jointing paving units and comprises a head 12 and a handle 14. The head 12 carries in this embodiment a pair of electrically driven vibration mechanisms 16,18. The head 12 is to be moved along a joint between adjacent paving units, imprinting a chosen profile in a compound pre-inserted between the paving units. Underside 20 of the head 12 is shaped for this purpose, being elongate in extent from a proximal end 22 to a distal end 24 and havingthe chosen profile in cross section. This profile is not seen in the drawing but the underside 20 may for example be a convex curve in cross section, to form a complementary concave curve in the compound. The head 12 is typically larger in width than the joints to which it is to be applied, so that it will contact upper edges of both of the adjacent paving units being jointed, thereby defining the depth of the profile imprinted into the compound. A middle portion 26 of the underside 20 is a ruled surface, which is to say that in side view it appears straight. The middle portion 26 contacts and profiles the compound, in use. Proximal and distal end portions 28, 30 of the underside 20 are ramped - inclined upwardly toward the ends of the head 12-so that whichever end leads as the head 12 moves alongthe joint will tend to glide over the compound and compress it into the joint, ratherthan digginginto orcollectingthe compound as a square end might do. The head 12 is in the present embodiment of metal construction. Since its underside 20 is subject to abrasion in use likely to remove any surface covering, a corrosion-resistant metal such as stainless steel is favoured. Weight of the metal head 12 keeps it in intimate contact with the joint without need for pressure to be exerted by the user. Nonetheless, other suitable materials may be substituted in other embodiments. The handle 14 of the jointing tool 10 is in the present embodiment elongate, so that the head 12 can be applied to joints at ground level while a user remains standing. The handle 14 is coupled at a lower end to the head 12 and is inclined to the middle portion 26 of the head’s underside 20, which makes it easy for the user to push or pull the head 12 along the joint whilst keeping the middle portion 26 roughly horizontal. In the present embodiment the handle 14 is adjustable in length. More specifically, the handle 14 is telescopic, comprising inner, intermediate and outer handle portions 32,34,36 received one within another as a sliding fit. Locking mechanisms are provided to lock the handle at a chosen length. A variety of suitable mechanisms is known to the skilled person. An upper end of the handle 14 carries a grip 38, inclined to the handle 14 to be roughly horizontal in use. The handle 14 may be, or be extensible to, at least 50 centimetres in length. The handle 14 may be, or be extensible to, at least 75 centimetres in length. The handle 14 may be, or be extensible to, at least 100 centimetres in length. The two vibration mechanisms 16,18 cause the head 12 to vibrate (oscillate) in use. Other embodiments may use a single vibration mechanism, or may use three or more vibration mechanisms. The amplitude of the head’s vibration is small. Each vibration mechanism 16,18 comprises a mass which is driven in a closed, repetitive path to produce vibrations. The path in question may be circular, or may be linear. While any suitable vibration mechanism may be adopted, the present embodiment uses an electric motor having an eccentric rotating mass (ERM). Compact vibration mechanisms of this type are known e.g. from mobile (cellular) phones and may be employed in the present invention. An alternative form of vibration mechanism which may be used in other embodiments is a linear resonant actuator, in which a mass coupled to a spring element is driven at its natural frequency by an electromagnetic coil. These too are known in relation to mobile (cellular) phones. A battery compartment 40 houses at least one electrical battery for driving the vibration mechanisms 16, 18. Related electronics may be provided for functions including battery management and recharging, indicatinga level of charge, and activation and control of the vibration mechanisms 16, 18, as well as adjusting the frequency of vibration in some embodiments. For example, high and low frequency settings may be provided for. Other vibration mechanisms may be used in other embodiments. For example, a piezoelectric actuator may be used to provide high frequency vibration. The vibration of the head 12 provides several advantages:- -testing shows that the vibrating head provides an especially smooth profile to the joint; -vibration of the head 12 reduces friction and any tendencyforthe head 12to stick as it is drawn along the joint; - the vibrating head 12 serves to agitate the compound in the joint, which is believed to improve the intimacy of its contact with the adjacent surfaces of the paving compound and so potentially to improve adhesion and durability; - the agitation of the compound may increase its depth of penetration into the joint; - the agitation of the compound may assist in breaking down any bubbles / cavities in it, and in increasing density of the compound; -the agitation of the compound is observed in use to consolidate it, bringing water (and in the case of resin-based compounds, resin) to the surface while sand particles settle downwardly, which again contributes to joint strength. Overall, trials of the jointing tool 10 have shown it to be highly efficacious in comparison to known, hand-held jointing tools without vibration. There is a synergy between the vibration of the head 12 and the use of an elongate handle, since the reduction in friction by the vibration of the head makes it easier to move the head 12 alongthe joint in a smooth and controlled manner despite the distance from the grip 38 to the head 12. Additionally, the elongate handle 14 helps to isolate the user’s hand from the vibrations of the head 12, reducing any likelihood of vibration-induced injury or harm such as white-finger syndrome (hand-arm vibration syndrome). Nonetheless, other embodiments of the invention may have the vibrating head without having an elongate handle. Thefrequency of vibration of the head 12 may be in the audible range of frequencies. The frequency may be:- above 20 Hertz; above 50 Hertz; above 100 Hertz; above 1000 Hertz. In any of these cases, the frequency of vibration of the head may be:- below 20,000 Hertz; below 500 Hertz; below 300 Hertz. An ultrasonic frequency may be used. The jointing tool 10 is well suited to use with both cement-based compounds and resinbased compounds. 5 The drawing depicts a prototype device used for testing. A production device will have a head 12 which forms a sealed enclosure around the vibration mechanisms 16,18, which can easily be washed after use e.g. by immersion in water. REFERENCE NUMERALS 10 10 jointing tool; 12 head; 14 handle; vibration mechanisms 16,18; 20 underside of head; 22 proximal end of head; 24 distal end of head; 26 middle portion of head’s underside; 28, 30 proximal and distal end portions of underside; 32 outer portion of handle; 34 intermediate portion; 36 inner portion of handle; 38 grip; 16, 18 vibration mechanisms; 40 battery compartment 15

Claims

1. A jointing tool for profiling a compound in a joint between two adjacent paving units, construction blocks, tiles or the like, the jointing tool comprising a head having an underside with a profile to be moved along the joint, thereby imparting a complementary profile to the compound in the joint, and a vibration mechanism for causing the head to vibrate in use.

2. Ajointingtool as claimed in claim 1 in which the underside of the head is elongate and has a convex cross-sectional profile.

3. A jointing tool as claimed in claim 1 or claim 2 in which the underside of the head is elongate and comprises a ruled surface.

4. A jointing tool as claimed in claim 3 in which the ruled surface comprises a middle portion of the underside of the head, and in which the underside of the head comprises at least one end region which is inclined upwardly in a direction away from the middle portion.

5. Ajointingtool as claimed in claim 4 in which there are end regions on both sides of the middle portion which are upwardly inclined in respective directions awayfrom the middle portion.

5. Ajointingtool as claimed in any preceding claim in which the underside of the jointing tool is formed by a metal component.

6. A jointing tool as claimed in any preceding claim in which the vibration mechanism comprises a mass which is driven repeatedly along a closed path to produce vibrations.

7. A jointing tool as claimed in any preceding claim in which the vibration mechanism comprises an eccentric rotating mass.

8. A jointing tool as claimed in any of claims 1 to 6 in which the vibrating mechanism comprises a sprung mass driven to oscillate by an electromagnetic actuator.

9. A jointing tool as claimed in any preceding claim in which the head forms a sealed enclosure for the vibrating mechanism.

10. A jointing tool as claimed in any preceding claim in which the head is coupled to an elongate handle.

11. Ajointingtool as claimed in claim 10 in which the handle is long enough to enable the user to stand upright while the head is engaged with a joint at ground level.

12. Ajointingtool as claimed in claim 10 or claim 11 in which the handle is adjustable in length.

13. A jointing tool as claimed in any of claims 10 to 12 when dependent on claim 3 in which the handle is inclined to the ruled part of the undersurface.

14. A jointing tool as claimed in any preceding claim in which the vibration mechanism is driven electrically.5 15. A method of profiling a compound in a space between two adjacent two adjacentpaving units, construction blocks, tiles or the like, the method comprising drawing a profiled underside of a head of jointing tool along the joint to impart a predetermined profile to the compound whilst the head of the jointing tool is driven to vibrate.

16. A method as claimed in claim 15 in which the head of the tool is driven to vibrate by10 an electrical vibration mechanism.

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