GB892655A - Portable grinding machine - Google Patents

Abstract

892,655. Grinding. MURSCHEL, E., and MESCHER, K. [trading as SCHEER & CIE, C. F.]. April 13, 1960 [April 23, 1959], No. 13165/60. Class 60. [Also in Group XXVIII] A portable grinding, sanding or polishing machine comprises a machine frame having a pulley mounted at both the front and rear ends thereof over which an endless abrading or like belt is trained, one of said pulleys being driven by an electric motor which drives also two fans one of which serves to cool the motor and the other serving to exhaust dust from the machine, the electric motor being located between the pulleys and being carried by a backing plate of the frame which serves also to support a housing in which the fans are located, said fans being driven directly by the motor shaft. The frame of the machine includes side, end and upper walls 11, 12, 13. Connected to, or integral with, the end wall 12 is a handle 15 having a switch 16 for starting and stopping an electric motor 18. The motor housing 19 is preferably integral with the side wall 11. The motor shaft 23 drives, through gears 24, 26, 27, a shaft 28 journalled in the side wall 11 and carrying a pulley 30. An endless abrading belt 36 travels about the pulley 30 and a pulley 32. A tensioning device 35 comprises resilient means to bias the pulley 32 away from the pulley 30 so as to tension the belt. Alternatively, the belt may be tensioned by a spring-biased roll engaging one of the runs 60 or 63, or the grinding shoe 38, which is shown integral With the motor housing 19, may be resiliently mounted thereon to tension the belt. The side wall 11 supports two fan casings 40,41. The interior of the casing 41 communicates with a discharge pipe 43 supporting a removable dust collecting bag 45. The pipe 43 may constitute a second handle. All rigid components of the machine are mounted below the level of the upper wall 13 so that the machine may be inverted and the surface 14 of the wall 13 rested on a supporting plate, thus providing a stationary grinder. The motor shaft 23 is directly connected with two coaxial fans 48, 49 rotatable in the casings 40, 41. Fan 48:draws cooling air through intake apertures 50 in the front wall of the motor housing 19, the air passing through the housing and being discharged through an aperture 52 in the casing 40. The fan 49 withdraws abraded particles, e.g. dust particles, through a cutout 58 in the side wall 11 communicating with the interior of the fan casing 41 whence the particles travel through the pipe 43 into the bag 45. A scraper 54 is adjustably fixed to the end wall 12. The fan casings 40, 41 are separated by a partition 42; this may be omitted if the fans are constructed and mounted in such a way that the air currents do not interfere. A window in the upper wall 13 is closed by a transparent pane for observation of the belt 36; on removal of the pane, one carbon brush 20 can be adjusted. A second window in the shoe 38 permits adjustment of the other carbon brush 21.