Motorized viscous material dispenser

1. A motorized viscous material dispenser ( 1 ; 1 a ), comprising,

a drive unit ( 11 ) with a cylindrical pinion gear ( 31 ),

a holder ( 15 ; 15 a ) attachable to a front side of the drive unit ( 11 ) for receiving at least one container containing viscous material,

at least one piston ( 19 ; 19 a ),

at least one rack ( 17 ; 17 a ) meshing with the cylindrical pinion gear ( 31 ) to drive said piston ( 19 ; 19 a ),

a rear piece ( 51 ; 51 a ), and

a guide piece ( 45 ; 45 a ),

wherein:

the drive unit ( 11 ) has a through channel ( 35 ) accommodating the at least one rack ( 17 ; 17 a ), said through channel ( 35 ) having a width providing for lateral displacement of the rack ( 17 ) in a direction of the rotational axis ( 39 ) of the cylindrical pinion gear ( 31 ),

the rear piece ( 51 ; 51 a ) and the guide piece ( 45 ; 45 a ) are separate to each other and separate to the drive unit ( 11 ),

the rear piece ( 51 ; 51 a ) is attachable to a rear side of the drive unit ( 11 ) opposite the front side,

the guide piece ( 45 ; 45 a ) is attachable to the front side of the drive unit ( 11 ),

said guide piece ( 45 ; 45 a ) and said rear piece ( 51 ; 51 a ) have guiding apertures ( 55 ) through which the rack ( 17 ; 17 a ) extends, and

said guiding apertures ( 55 ) determine the position of the rack ( 17 ; 17 a ) relative to the cylindrical pinion gear ( 31 ), when the motorized viscous material dispenser ( 1 ; 1 a ) is assembled.

2. The dispenser according to claim 1 , wherein the dispenser is a caulking gun.

3. The dispenser according to claim 1 , wherein the guide piece ( 45 ; 45 a ) is a part of the holder ( 15 ; 15 a ).

4. The dispenser according to claim 1 , wherein the guide piece ( 45 ; 45 a ) and the rear piece ( 51 ; 51 a ) are fastened to the drive unit by mechanical fasteners ( 43 , 49 ).

5. The dispenser according to claim 1 , further comprising more pistons ( 19 ) and more racks ( 17 ) each rack ( 17 ) being guided by apertures ( 55 ) of the guide piece ( 45 ) and the rear piece ( 51 ).

6. The dispenser according to claim 1 , further comprising at least one guide rod ( 23 ) extending parallel to the at least one rack ( 17 a ).

7. The dispenser according to claim 1 , further comprising an electric motor ( 27 ) driving the pinion gear ( 31 ).

8. The dispenser according to claim 7 , further comprising a battery ( 13 ) for energizing the electric motor ( 27 ).

9. The dispenser according to claim 1 , wherein the pinion gear ( 31 ) has straight teeth ( 33 ).

10. The dispenser according to claim 1 , wherein the rack defines a longitudinal axis and wherein the lateral displacement of the rack is a displacement transverse to said longitudinal axis.

11. The dispenser according to claim 10 , wherein said longitudinal axis is parallel to a direction of movement of the rack when driving said piston.

12. The dispenser according to claim 10 , wherein the lateral displacement of the rack is a displacement perpendicular to said longitudinal axis.

13. The dispenser according to claim 1 , wherein the cylindrical pinion gear comprises teeth extending into the through channel to allow both a single rack or more than one rack to be accommodated in the through channel to mesh with the teeth of the pinion gear.

14. The dispenser according to claim 1 , wherein the pinion gear extends across the entire width of the through channel.