Surface maintenance machine having air recirculation

• US 4,310,944 A
• Filed: 04/07/1980
• Issued: 01/19/1982
• Est. Priority Date: 01/30/1978
• Status: Expired due to Term

• Current Assignee: Tennant Company
• Original Assignee: Tennant Company
• Inventors: Thomsen, Donald L., Kroll, Harley E.
• Primary Examiner(s): MOORE, CHRISTOPHER K
• Application Number:
  US06/137,572
• Time in Patent Office: 652 Days
• Field of Search: 15/340, 15/345, 15/346, 15/347, 15/349
• US Class Current: 15/346
• CPC Class Codes: A47L 11/40 Parts or details of machines not provided for in groups A47L11/02 - A47L11/38, or not restricted to one of these groups, e.g. handles, arrangements of switches, skirts, buffers, levers
• CPC Class Codes: E01H 1/0854 Apparatus in which the mechanically dislodged dirt is partially sucked-off, e.g. dislodging- sweeping apparatus with dirt collector in brush housing or dirt container mechanical dislodging machines with independent suction nozzles E01H1/0827; combined with blowing and suction E01H1/0872
• CPC Class Codes: E01H 1/0872 with mechanical loosening or feeding instruments for the dirt to be removed pneumatically, e.g. brushes, scrapers brushing installations per se E01H1/02; other loosening devices per se E01H1/105

Abstract

A powered sweeping machine is disclosed, particularly suitable for efficiently removing light and heavy weight litter from surfaces such as parking lots, warehouse floors and the like. The machine includes a main frame carrying a hopper and a powered brush. The brush operates through an opening in the lower side of a brush housing. The hopper is separated into a debris receiving compartment and a filter compartment. An air fan and an associated duct recirculates air from the far end of the debris compartment to a zone adjacent the brush. This nonfiltered air is discharged into the brush housing and again moved through the debris compartment to aid in moving debris to the far end of the debris compartment. A fan is provided for withdrawing a portion of the air from the filter compartment and discharging the air to the ambient atmosphere. The withdrawal of a portion of the air results in more air flowing into the brush housing than is recirculated through the brush housing and thus provides dust control at the base of the brush housing.

Claims

1. A surface cleaning machine having a normally longitudinally forward direction of movement, said machine comprising a frame, a plurality of surface engaging wheels suitable for supporting said frame, a debris pickup housing supported by the frame, said housing having a downwardly facing opening and a debris discharge opening, means for sweeping material from beneath said housing through the debris discharge opening, a hopper supported by the frame, said hopper having a debris inlet opening directly communicating with the housing discharge opening, said hopper having a portion remote from the debris inlet opening, a single blower for withdrawing air from said hopper remote portion and a filter chamber associated with said hopper, said single blower moving one portion of the air through said filter chamber and from thence to the ambient atmosphere and simultaneously moving a second portion of air into the hopper, thereby recirculating said second portion of air under pressure whereby at least a substantial quantity of said air moves again through said hopper to assist in propelling light weight debris in a direction toward said remote hopper portion thereby facilitating picking up debris and filling of said hopper with debris.

2. The surface cleaning machine of claim 1 wherein said machine includes diverter means for separating the air flow into a recirculation air flow and a filter air flow.

3. The surface cleaning machine of claim 1 wherein the direction of rotation of said brush is such as to sweep debris directly through said debris discharge opening.

4. A surface cleaning machine having a normally longitudinally forward direction of movement, said machine comprising a frame, a plurality of surface engaging wheels supporting said frame, a brush housing supported on the frame, said brush housing having a downwardly facing opening and a debris discharge opening, a power driven brush mounted in the housing for rotation about a transverse axis, said brush being adapted to engage the surface to be cleaned while directing swept material toward the debris discharge opening, a hopper supported on the frame, said hopper having a debris inlet opening communicating with the brush housing discharge opening, said hopper having an upper portion remote from the debris inlet opening, air recirculating means comprising a single blower for withdrawing air from said hopper upper portion and discharging a first portion of said air to the atmosphere and a second portion of said air under pressure into the brush housing, whereby at least a substantial quantity of said air moves again through the housing, debris discharge opening and hopper to assist in propelling light weight debris in a direction toward said hopper upper portion thereby facilitating filling of said hopper with debris.

5. The apparatus of claim 4 wherein the hopper has a divider wall for separating the hopper into a filter compartment and the debris compartment, said divider wall having a port opening therethrough that places the filter compartment in fluid communication with the debris compartment at a location remote from the hopper debris inlet.

6. The apparatus of claim 5 further including a screen extending across the debris compartment and spaced from the divider wall to provide an air flow space therebetween, said screen serving to block bulky material being carried by the airstream to the divider wall port, said divider wall port and air recirculating means inlet opening being on the opposite side of the screen from the hopper debris inlet.

7. The apparatus of claim 4 wherein the brush is rotatably mounted on pivotable arms, said arms having first end portions remote from the brush, and means for mounting said first end portions to said housing for transverse pivotal movement.

8. A surface cleaning machine comprising a frame, surface engaging wheels mounted on the frame, a brush housing mounted on the frame, said brush housing having a brush opening that opens downwardly and a debris discharge opening, a power driven brush mounted in the housing for rotation about a transverse axis, said brush being adapted to engage the surface to be cleaned and to direct swept material through the debris discharge opening, a hopper mounted on the frame, said hopper having a debris inlet opening in direct communication with the housing discharge opening, said hopper having an upper portion remote from the debris inlet opening, air recirculating means including a single blower for withdrawing air from said hopper upper portion and discharging air under low pressure through the housing and through the debris discharge opening, said hopper having a debris receiving portion and filter means for separating debris particles from an airstream, said single blower including means for discharging a first filtered portion of air to the ambient atmosphere and recirculating a second unfiltered portion of said air.

9. A surface cleaning machine having a normally longitudinally forward direction of movement, said machine comprising a frame, a plurality of surface engaging wheels suitable for supporting said frame, a debris pickup housing transported by the frame, said debris pickup housing having a downwardly facing opening and a debris discharge opening, means adapted to engage the surface to be cleaned and direct swept material through the debris discharge opening, a hopper supported with respect to the frame, said hopper having a debris inlet opening adjacent one end thereof, said inlet opening communicating directly with the debris pickup housing discharge opening, said hopper having an air outlet opening associated with the end opposite said one end, said air outlet opening being remote from the debris inlet opening, air recirculating means comprising a single blower for withdrawing air from said hopper through said air outlet opening and discharging a first portion of said air under pressure into the debris pickup housing whereby at least a substantial quantity thereof moves through the housing and again through said hopper to assist in propelling light weight debris in a direction toward said opposite end in said hopper thereby increasing the effective capacity of said hopper, said single blower including means for discharging a second portion of said air through a filter and into the atmosphere.

10. The surface cleaning machine of claim 9 wherein said means for engaging said surface is a power driven cylindrical brush mounted in the housing for rotation about a transverse axis and wherein the direction of rotation of said brush is such as to sweep debris directly through said debris discharge opening.