Propulsion device and backpack

Abstract

A propulsion device configured to impart movement to a skate- or ski-type vehicle with a person standing thereon for pushing or pulling the person can include a frame, a motor, a drivable member, a plurality of legs, and at least one lock. The motor can be mounted on the frame. The drivable member can be mounted on the frame and driven in motion by the motor. The plurality of legs can each be mounted on the frame for pivoting movement between a respective retracted position and a respective extended position. The at least one lock can be disposed to selectively lock the plurality of legs in the respective retracted positions. A backpack can be configured to hold the propulsion device.

What is claimed is: 
     
         1 . A propulsion device configured to impart movement to a skate- or ski-type vehicle with a person standing thereon for pushing or pulling the person and comprising:
 a frame;   a motor mounted on said frame;   a drivable member mounted on the frame and driven in motion by said motor;   a plurality of legs each mounted on said frame for pivoting movement between a respective retracted position and a respective extended position; and   at least one lock disposed to selectively lock said plurality of legs in said respective refracted positions.   
     
     
         2 . The propulsion device of  claim 1  further comprising:
 at least one biasing member urging at least one of said plurality of legs into said respective extended position. 
 
     
     
         3 . The propulsion device of  claim 2  further comprising:
 a mounting member configured to support a camera and mounted on said frame between said plurality of legs. 
 
     
     
         4 . The propulsion device of  claim 1  further comprising:
 at least one movement supporting member positioned at a distal end of at least one of said plurality of legs. 
 
     
     
         5 . The propulsion device of  claim 4  wherein said at least one movement supporting member is further defined as a wheel. 
     
     
         6 . The propulsion device of  claim 4  wherein said at least one movement supporting member is further defined as a ski. 
     
     
         7 . The propulsion device of  claim 1  wherein said drivable member is further defined as a wheel. 
     
     
         8 . The propulsion device of  claim 1  wherein said drivable member is further defined as a track. 
     
     
         9 . The propulsion device of  claim 1  further comprising:
 a clamp mounted on said frame and configured to selectively clamp on a wheeled- or ski-type vehicle. 
 
     
     
         10 . The propulsion device of  claim 1  further comprising:
 a mounting member configured to support a camera and mounted on said frame. 
 
     
     
         11 . A backpack configured to hold the propulsion device of  claim 1 . 
     
     
         12 . The backpack of  claim 11  comprising:
 a primary body defining a primary cavity and having an outer surface; 
 a secondary body having an opening surrounded by said outer surface and defining a secondary cavity, wherein said secondary body is at least partially positioned within said primary cavity. 
 
     
     
         13 . The backpack of  claim 12  wherein said primary body is flexible and said secondary body is rigid. 
     
     
         14 . The backpack of  claim 12  wherein said opening is substantially flush with said outer surface. 
     
     
         15 . The backpack of  claim 12  further comprising:
 at least one door extending across at least a portion of said opening and pivotable between an open position and a closed position. 
 
     
     
         16 . The backpack of  claim 12  further comprising:
 a plurality of doors extending across a majority of said opening, each of said plurality of doors pivotable between a respective open position and a respective closed position, said plurality of doors being configured to at least one of pivot and slide. 
 
     
     
         17 . The backpack of  claim 16  wherein a gap is defined between said plurality of doors when each of said plurality of doors is in said respective closed position. 
     
     
         18 . The backpack of  claim 16  further comprising:
 a plurality of biasing devices each arranged to bias one of said plurality of doors to said respective closed position. 
 
     
     
         19 . The backpack of  claim 12  wherein said secondary cavity includes a first portion and a second portion shaped substantially similarly and spaced from one another. 
     
     
         20 . The backpack of  claim 19  wherein said secondary cavity includes a third portion shaped differently from and positioned between said first portion and said second portion.