Patent Publication Number: US-4094034-A

Title: Floor treatment machines

Description:
This invention relates to floor treatment machines of the rotary brush type in which the weight of the machine is supported by the rotary brush or brushes. 
     The expression &#34;brush&#34; as herein used should be deemed to include polishing or buffing pads in addition to scrubbing or polishing brushes. 
     In such machines vibration of the machine may arise when the brush wobbles in operation, e.g. if the plane of the bristle tips or surface in engagement with the floor is not exactly perpendicular to the axis of rotation. 
     In order to overcome this, it has previously been proposed to introduce a degree of flexibility into the final drive coupling to the brush, for example by having a rubber cushion between the brush back and the final drive shaft. However, the considerable preloading due to the machine weight leads to some lack of consistency in operation and difficulties in ensuring that wobbles over a range of intensity can be absorbed satisfactorily. 
     According to the present invention, there is provided a floor treatment machine of the rotary brush type in which a brush mounting member is flexibly suspended between resilient elements for limited universal movement. 
     Preferably, the resilient elements are upper and lower resilient rings of substantially similar stiffness. 
     In an arrangement in which one of the rings normally transmits the weight of the machine to the mounting member, the other ring may be stiffened by the geometry of its seating to bring the rings into substantial similarity of stiffness. 
    
    
     The invention will be further described with reference to the accompanying drawings, in which: 
     FIG. 1 is a sectional view through a brush and final drive train of a preferred form of machine according to the present invention; and 
     FIG. 2 is a scrap section showing a modification of FIG. 1. 
    
    
     FIG. 1 shows part of a machine chassis 1 which supports, by means of bearings 2, a hollow shaft 3 having a flange 4 to which is secured a final drive pulley 5 by means of bolts 6. The shaft 3 is received over a static pilot sleeve shaft 25. Drive is transmitted to the pulley 5 by means of a belt shown at 7. The pulley 5 has an annular series of holes 8, and an annular seat 9. 
     A brush support member consists of a flange 11 and a spigot 12 which is received within a socket in an upstanding boss 13 forming part of a brush adapter plate 14 which is screwed to the back of a conventional brush 15. The adapter plate 14 also carries upstanding dogs 16 cooperable with the annular series of holes 8 to provide a drive connection between the pulley 5 and the brush 15. The outer surface of the boss 13 is provided with parallel ribs 17 defining two cavities 18 adapted to receive a spring clip 19 located in a recess in the pulley 5. The engagement of the clip 19 in either cavity 18 prevents the brush from falling from the machine when it is clear of the ground while the machine is being carried on transport wheels, while allowing the brush to be removed by a sharp tug. 
     Attention is drawn to our co-pending application filed simultaneously herewith and entitled &#34;Improvements in or relating to brush retention means for floor treating machines&#34;. 
     The flange 11 of the brush mounting member extends between the flange 4 and an inwardly extending flange 20 of the pulley 5 and is supported between upper and lower rubber rings 21 and 22 respectively, each being of O section and having similar flexibility characteristics. 
     The weight of the machine is transmitted to the brush retention member through the upper ring 21, which is thus effectively somewhat stiffer than the ring 22, but this difference is compensated by the curvature of the seat 9 provided in the pulley 5 for retention of the ring 22, the effect of this curved seating being to increase the stiffness of the ring 22. 
     It will be appreciated that if the stiffnesses of the rings 21 and 22 are not effectively the same, rocking of the brush 15 will give rise to some vertical motion of the machine. This phenomenon arises from the fact that an upward motion of one side of the flange 11 gives rise to an equal and opposite motion of the opposite side of the flange 11 and unless these movements are resisted by rings of similar stiffness, there will be a net vertical motion of the machine itself. 
     It will be appreciated that it may prove, in certain circumstances, necessary to have the ring 22 made of stiffer material or of different shape to ring 21 to compensate for the fact that the ring 21 is normally under very considerable pressure arising from the weight of the machine. 
     In the modification shown in FIG. 2, there is provided a part spherical bearing surface 26 mounted on the pilot shaft 25 and cooperable with a concave bearing surface 27 in the brush support member. This arrangement acts as a swivel thrust bearing to transfer the weight of the machine onto the brush while allowing the brush to wobble in operation. The rubber rings 21 and 22 have only to provide resilience to counteract the tilt of the machine. They can therefore be more resilient than if they have to transmit weight and provide better isolation. The seats for the rings 21 and 22 may then be of similar configuration as shown. 
     Various other modifications may be made within the scope of the invention.