Field of the invention

The invention relates to a joint for cleaning tools, which is generally adapted to be used to attach a broom or scrubbing brush to a bristled base.

Background art

A cleaning tool, typically a broom or a scrubbing brush, is known to comprise a base portion substantially consisting of a straight body which is equipped with a multiplicity of bristles on a side designed to face the ground or a surface to be cleaned.

Typically, the base portion comprises, on the opposite side, a joint for stable fixation thereto of a broomstick that allows users to handle the broom or the scrubbing brush.

A prior art joint comprises a raised shank, which defines a hollow seat for receiving the end of a broomstick precisely fitted therein.

A fixation system is provided between the end of the broomstick and the shank, generally consisting of a screw connection consisting of male threads formed on the end of the broomstick and mating female threads formed in the inner peripheral walls of the hollow seat, which engage with the male threads by screwing.

The end portion of the broomstick, having the male threads, also have a slightly frustoconical shape, such that as it screws into the female threads, a more secure and stable connection is achieved.

A further connection arrangement between the end of the broomstick and the base portion of the broom or the scrubbing brush comprises a pair of holes transversely extending through both, such that they are coaxial when the broomstick fits in the hollow seat.

Then, a bolt, with a respective locknut or a plug, is transversely introduced therein, for locking the broomstick in the hollow seat.

A further known connection between the end of the broomstick and the base portion of the broom or scrubbing brush comprises a series of flexible petals which overhangingly extend from the upper circumference of the shank, namely projecting therefrom, toward the broomstick.

The shank has external threads for a threaded ring to be screwed thereupon, the latter having an internal frustoconical profile which is designed to fit onto the outer surfaces of the petals as the ring is progressively tightened onto the shank, thereby forcing them to progressively converge in the centripetal direction of the shank.

As a result, as the ring is screwed upon the shank, the end of the broomstick is clamped between the petals, and the broomstick is locked in the shank. This prior art suffers from certain drawbacks.

A first drawback is that, with brooms or scrubbing brushes having a considerably long base portion, as is typical for industrial brooms or scrubbing brushes, the shank is exposed to mechanical bending stresses caused by the torque generated between the active force imparted by the user through the broomstick and the passive friction force which is generated, during cleaning, by the contact of the bristles with the surface to be cleaned.

A second drawback is that, due to the length that is typically associated with the base portions of these brooms or scrubbing brushes, the shank of the joint is typically offset, namely proximate to the end of the base portion that is closer to the user during operation, i.e. the proximal end.

This offset position generates an additional stress on the shank and the joint in general, due to the overhanging weight of the base portion which extends along the shank, i.e. from the joint of the broomstick outwards.

These stresses often cause early fatigue of the joint, with cracks and fractures occurring therein and leading, even when they only partially affect the joint, to an increasing clearance formed between the broomstick and the shank.

As such clearance increases, it can cause the broomstick from spontaneously slip off the shank or the shank to even break, which will eventually make the broom or scrubbing brush unusable, due to the impossibility of using the broomstick. A further source of detrimental stresses consists of impacts against surrounding obstacles, which often act upon the base portion as it is being used by users.

Once again, such stresses are transferred to the joint of the broomstick thereby further increasing the probability of damages or ruptures.

A further drawback is that, as a result of intensive use, the aforementioned clearances, and the impacts of the base element against obstacles around the surfaces to be cleaned, the broomstick may rotate relative to the base element, thereby preventing the user from restoring the locked state and firmness of the joint.

Disclosure of the invention

One object of the invention is to improve the prior art.

A further object is to provide a joint for cleaning tools that has a very simple and hence highly cost-effective structure.

In one aspect the invention relates to a joint for cleaning tools as defined by the features of claim 1 .

Further aspects of the invention are defined in the dependent claims.

The invention affords the following advantages:

- preserving the integrity of the joint with time, even when it is exposed to mechanical stresses during use of the cleaning tools;

- selectably adjusting the position of broomsticks relative to the base elements of the cleaning tools;

- avoiding inadvertent accidental rotations between the broomsticks and the base elements of the cleaning tools during use.

Brief description of the drawings

Further characteristics and advantages of the invention will be more apparent from the detailed description of a preferred, non-exclusive embodiment of a joint for cleaning tools, which is shown as non-limiting example in the annexed drawings, in which:

FIG. 1 is a small-scale general view of a cleaning tool, namely a broom for industrial use and for outdoor use; FIG. 2 is a large-scale broken view of a first embodiment of a joint for cleaning tools of the invention;

FIG. 3 is a perspective broken view of a step in which one end of a broomstick is fitted into a shank that forms a part of the joint of the invention; FIG. 4 is a cross sectional top view of the shank of Figure 13;

FIG. 5 is a top perspective broken view of a second embodiment of the shank of Figure 4;

FIG. 6 is a perspective broken view of a second possible embodiment of a joint for cleaning tools of the invention;

FIG. 7 is a very large-scale view of an area of insertion of a broomstick into a shank of the joint of Figure 6;

Fig. 8 is a broken view of a detail of the locking arrangement of the broomstick in the shank of Figure 7;

FIG. 9 is a sectional view of the joint of Figure 6 during insertion of a broomstick;

FIG. 10 is a large-scale view of the joint of Figure 9, in a state in which the broomstick is inserted in the shank of the joint of Figure 6;

FIG. 1 1 is a detail view of a component of the joint according to a possible alternative embodiment;

FIG. 12 is cross sectional view of an alternative embodiment of the joint;

FIG. 13 is a cross sectional view of the joint of Figure 5;

FIG. 14 is a longitudinal sectional view of the second possible embodiment of a joint for cleaning tools of the invention.

Detailed description of a preferred embodiment Referring to the accompanying figures, numeral 1 generally designates a cleaning device, namely a broom, typically for industrial or road use, and hereinafter referred to as broom 1 .

The broom 1 comprises a base body 2, briefly referred to hereinafter as body 2, which has a flat elongate shape and extends along a longitudinal axis "X". The body 2 has a mass 3 of bristles 3 on one side 2A that faces a surface to be cleaned, such bristles being namely oriented in an inclined direction, forming an acute angle with the base body 2.

On the opposite side 2B, the body 2 forms a joint 5 for an operating broomstick 4, typically formed as a segment of a cylindrical tube, which has a joint end 4A and an opposite grip end 4B.

More in detail, the joint is shown to comprise a shank 6 which raises from the side 2B and in which the joint end 4A of the broomstick 4 is designed to be inserted and locked, although removably.

In a first embodiment, the shank 6 is formed as one piece which raises from the side 2B whereas, in a second embodiment the shank, here referenced 60, is formed as a prismatic element 61 rotatably mounted in a specially designed seat 62 formed in the base body 2 and adapted to be locked in a position selected from a series of available positions provided as a plurality of through holes 63 arranged in an arc of a circle on a pair of walls 64 placed on two sides of the element 61 and delimiting the seat 62.

Back to the first embodiment, the shank 6, which is formed in a position that is close to the proximal end 2C of the base body 2, i.e. closer to a user, is composed of two semicircular walls 6A, 6B which are in mutual facing relationship and are divided by a groove 7 that extends along the longitudinal axis "X" over a section of a reinforcement rib 20 that joins the shank 6 to the base body 2.

More in detail, the shank 6 is shown to be inclined relative to the base body 2 and not perpendicular thereto, thereby forming an acute angle "a" therewith toward the proximal end 2C and, as a result, a supplementary obtuse angle "β" toward the opposite distal end, referenced 2D.

A preferred acute angle "a " of inclination of the shank 6 may range from 60 ° to 70 °, and be indicatively of 67°.

Two coaxial holes 8 are formed in the shank 6, namely one hole 8 in each of the two walls 6A, 6B, which share a common axis "Y", perpendicular to the longitudinal axis "X", and which may receive the shaft of a bolt 9 that extends therethrough and can be screwed against the two walls 6A, 6B.

In order to act against the two walls 6A, 6B, the bolt 9 has a typically hexagonal head 9A, leaningly received in a hollow hexagonal seat 1 1 formed outside one of the walls 6A, 6B (for example the wall 6B), at one of the holes 8, with the opposite threaded end 9B projecting out of the opposite wall 6A, and extending through a seat 12, with a nut tightened thereupon, e.g. a wing nut 10.

More in detail, referring to Figure 8, it shall be noted that one side 10A of the nut 10 facing the corresponding seat 1 1 and the facing surface 1 1 A of the latter define two arc-shaped mating profiles, which have the purpose of automatically centering the position of the nut 10 as the bolt 9 is tightened. Also the joint end 4A of the broomstick 4 has two coaxial through holes 13 which are substantially coaxially aligned when the broomstick 4 is received in the shank 6 in its final position, with the two holes 8 formed in the walls 6A, 6B, such that, as the bolt 9 is introduced therein, it also extends through the joint end 4B thereby locking it in the shank 6.

Rotation locking means are provided between the joint end 4A and the shank 6, namely the bottom 6C of the latter, to prevent the broomstick 4 from rotating on itself once it has been inserted into the shank 6.

Referring to Figures 3, 4 and 13, the rotation locking means, in a possible embodiment, comprise two recesses 14, preferably having a semicircular shape, which are formed at the base of the joint end 4A in diametrically opposite positions, and are designed to engage with corresponding teeth 15 formed in raised form from the bottom 6C, also in diametrically opposite positions.

In order to obtain a firmer connection between the joint end 4A and the shank 6, the latter may contain a second cylindrical shank 16, which extends coaxially within the shank 6 along a section thereof, and has a smaller diameter, such that an annular gap 17 is defined therebetween, for the end 4A to fit therein.

The second shank 16 may have an inner diametrical reinforcement partition, referenced 16A and designed to fit into the end 4A with a slight press-fit, thereby maintaining it coaxially guided without clearances therebetween. For easier introduction into the end 4A, the second end 16 may have, if needed, a slightly conical profile.

Furthermore, in order to allow the passage of the bolt 9, the second shank 16 may also have holes or recesses 18 coaxial with the holes 8.

Referring now to Figures 6 to 10 and 14, which show a second embodiment of the joint of the invention, it shall be noted that the parts in common with the first embodiment as described above have been designated by the same numerals.

It will be appreciated that, in this second embodiment, the shank 60 is formed as a prismatic element 61 composed of two portions 65 fixed to each other in symmetric relationship.

As mentioned above, the prismatic element 61 is mounted in such a manner as to be able to rotate within the seat 62 about the transverse bolt 9, such that it can assume different angles relative to the body 2.

The rotations of the prismatic element 61 can be selected by inserting a plug 66 into a selected one of the holes 63, the plug being inserted parallel to the bolt 9 and, when inserted, interfering with the base of the prismatic element 61 , namely engaging with a cavity of teeth 67 formed therein, as shown in Figures 9 and 10.

A groove 7 is also provided between the two symmetric portions 65, and allows them to slightly bend toward each other when stressed, as more clearly discussed below.

Once again in this second embodiment, a second shank may be provided concentric with the shank 60, here referenced 68 in Figure 9.

More in detail, this second shank 68, which has the same purpose as the second shank 16, is provided in the form of a body separate from the prismatic body 61 and contained within the two symmetric portions 65.

For this purpose, the second shank 68 has a substantially flat base 69, which extends peripherally therefrom and is received between respective parallel ribs 70 (see also Figure 14) provided in raised form from the inner walls of the two symmetric portions 65 which, when coupled, guide and clamp the base 69 therebetween, thereby fixing the second shank 68 in a predetermined position coaxially within the shank 60.

As shown in the figure, the second shank 68 is provided in the form of two perpendicular ribs 71 , 72, formed of one piece with the base 69.

This second shank 68 also has a transverse channel 73 for the passage of the bolt 9 and the two teeth 15 designed for engagement with the recesses 14 of one joint end 4A of a broomstick 4 are provided at the engagement area between the two ribs 71 and 72 at the base 69.

Referring to Figure 14, one of the two symmetric potions 65 has been removed to provide a view of the interior of the joint.

More in detail, it will be appreciated that the plug 66 is inserted in a selected one of the holes 63 and is received between one of the cavities of the teeth

67 in an opposite parallel groove formed in mating teeth 67B on the inner surface of the seat 62.

In another embodiment, as shown in Figures 1 1 and 12, the second shank

68 may be also formed as a prismatic, e.g. frustoconical projection, which extends from the bottom face of the base 69 and is designed for precision-fit in a hollow seat 75 formed in the bottom 6C (see Figure 4), whose shape is the reverse of the prismatic shape of the projection 74.

The skilled person will understand that a reversed arrangement may be provided of the projection 74, to be provided in raised form from the bottom 6c, and the hollow seat 75, to be formed at the base of the second shank 68. A further characteristic that is common to both embodiments of the joint of the invention is the provision of a strong reinforcement rib 20 which connects the shanks 6 and 60 to the opposite side 2B of the body 2, thereby extending along the longitudinal axis "X", over a section thereof.

The operation of the joint for cleaning tools is explained below for both possible embodiments.

In the first embodiment, the bolt 9, if any, is removed from the shank 6, and the joint end 4A of the broomstick 4 is inserted in the latter, for the second shank 16 to fit therein. In the latter case, the joint end 4A of the broomstick 4 is received by precise fit in the annular gap 17.

In this inserted configuration of the broomstick 4, the two teeth 15 are engaged in their respective recesses 14, thereby preventing the broomstick 4 from rotating on itself.

In order to also safely and firmly lock the latter against axial sliding movement in the shank 6 to prevent accidental removal therefrom, the bolt 9 is transversely inserted into the two holes 8 and into the holes 13 of the broomstick 4 aligned with the former, for the head 9A and the opposite end 9B to remain within the shank 6, received in their respective seats 1 1 an 12. Then, the nut 10 is screwed onto the opposite end 9B and, as it is tightened, the two walls 6A, 6B are bent toward each other, and partially fill the gap of the groove 7, as shown by dashed lines in Figure 4.

This, the joint end 4A of the broomstick 4 is captured within the shank 6 and fits onto the second shank 16 which penetrates it, reinforces it and maintains it in a guided position.

According to the second embodiment of the joint for cleaning tools, the broomstick 4 is inserted in much the same manner as the first embodiment, except that the joint end 4A of the broomstick 4 is received between the two symmetric portions 65 that form the shank 60.

Once again, insertion occurs by first removing the bolt 9, such that the joint end 4A of the broomstick 4 freely fits onto the second shank 68 thereby allowing mutual engagement of the teeth 15 and the recesses 14.

In this engagement step, the plug 66 is typically (but not necessarily) also removed from the prismatic element 61 , which is thus free to rotate within the seat 62, between the walls 64 at the two sides.

Once the broomstick 4 has been entirely inserted into the shank 60, the bolt 9 is transversely inserted and extends through the two holes 8, the two holes 13 of the joint end 4A and the channel 73, if any, to extend on the opposite side of the prismatic element 61 .

The nut 10 is screwed upon the projecting portion 9B of the bolt, and progressively bends the two symmetric portions 65 toward each other, which partially fill the groove 7 and clamp the joint end 4A between them.

Once such engagement has been completed, the broomstick 4 is rotated relative to the body 2 until it reaches an optimal position for ergonomic use of the broom 1 ,

When the optimal position has been reached, the plug 66 is fitted into a corresponding hole 63 and engages in one of the cavities of the teeth 67 thereby locking the rotation of the prismatic element 61 , and hence the broomstick 4, in the selected position.

It should be noted that the mating concave/convex conical coupling between the two profiles of the side 10A of the nut 10 and the surface 1 1 A of the seat 1 1 during screwing, allows the nut 10 to be self-centered on the surface 1 1 A, thereby avoiding the generation of transverse stress components.

Therefore, in both embodiments, when the broomstick 4 is fitted in the shank 6 or 60, it cannot rotate on itself or be accidentally slipped off.

The shape of the shanks 6 and 60 and the provision of the second shanks 16 and 68, prevents the creation of detrimental clearances between the broomstick 4 and the body 2.

Furthermore, the provision of the reinforcement rib 20 allows all the stresses generated during use of the broom 1 to be discharged on the joint of the invention without any risk of damage.

The invention has been found to fulfill the intended objects.

The invention so conceived is susceptible to changes and variants within the inventive concept.

Also, all the details may be replaced by other technical equivalent elements. In its practical implementation, any material, shape and size may be used as needed, without departure from the scope as defined by the following claims.