Flatcar for carrying the burden
AssigneeSagami Tsushin Kogyo Kabushiki Kaisha
InventorTakashi Nanzai
Life of this patent
Estimating the term…
Abstract
A handtruck for use in carrying a load, comprises springs installed on a frame, a connection shaft received rotatably in bearings mounted on the opposite end portion of the springs and substantially parallel with the lateral extend of the frame, a support member for supporting a first pair of wheels which is fixed to the connection shaft, and another support member for supporting a second pair of wheels which is also firmly fixed to the same. A rotation shaft is rotatably mounted on the support member for supporting the second pair of wheels in order to cause the second wheels to rotate around the shaft axis approximately normal to the axis of the connection shaft.
Claims20
A hand truck comprising an unsprung frame, a sprung carriage means, double thickness spring means resiliently supporting said carriage means from said frame, said double thickness spring means comprising a pair of generally U-shaped spring band elements with each band element having a curvilinear U-shaped intermediate section connecting a first and a second end section, the first end section of each band element of each pair being in abutting relationship with each other, and the second end section of each pair being in abutting relationship with each other, the U-shaped intermediate section of each band element of each pair being spaced from one another, said first and second abutting end sections converging toward said spaced intermediate sections to define an opening spring angle between said first and second abutting end sections, said two abutting first end sections being connected to said frame, said two abutting second end sections having rotating means rotatably supporting said carriage means, said carriage means comprising wheel support means which rotatably support first wheel means for rotation about a first rotational axis and which also rotatably support second wheel means for rotation about a second rotation axis, said hand truck being operable in a stair-climbing operational mode in which said first and second rotational axes are substantially parallel to one another and in which said first and second rotational axes defining a support means plane which extends between and which contains said first and second rotational axes, said frame means defining a load-receiving surface on which the load to be carried by the hand truck is disposed, said carriage means being resiliently supported from said frame means by said double thickness spring means such that as the hand truck progressively moves up successive steps, the angle of said support means plane relative to horizontal varies while the angle of said load-receiving surface relative to horizontal remains substantially constant as said opening spring angle varies.
A hand truck for carrying a load comprising a frame for receiving said load, a carriage means, double thickness spring means resiliently supporting said carriage means from said frame, said carriage means having a connecting shaft means, said double thickness spring means comprising a pair of generally U-shaped spring band elements with each band element having a curvilinear U-shaped intermediate section connecting a first and a second end section, the first end sections of each band element being abutting relationship with each other and the second end section of each band element being in abutting relationship with each other, the U-shaped intermediate sections of each band element being spaced from one another, said first and second abutting end sections converging toward said spaced intermediate sections to define an opening spring angle between said first and second abutting end sections, said abutting first end sections being connected to said frame, said abutting second end sections having rotating means rotatably supporting said connecting shaft means, said carriage means further comprising support means mounted on said connecting shaft means, first wheel support means mounted on said support means and rotatably supporting first wheel means for rotation about a first rotational axis, and second wheel support means mounted on said support means for rotatably supporting second wheel means for rotation about a second rotational axis, said hand truck being operable in a stair-climbing operational mode in which said first and second rotational axes are substantially parallel to one another and in which said first and second rotational axes are each substantially horizontally disposed, said first and second rotational axes defining a support means plane which varies relative to horizontal as the hand truck moves up a stairs in said stair-climbing operational mode, said frame being disposed at a substantially constant angle relative to horizontal as said opening spring angle varies as the hand truck moves up said stairs in said stair-climbing operational mode.
A hand truck for carrying a load comprising a frame for receiving said load, a carriage means, double thickness spring means resiliently supporting said carriage means from said frame, said carriage means having a connecting shaft, said double thickness spring means comprising a pair of generally U-shaped spring band elements with each band element having a curvilinear U-shaped intermediate section connecting a first and a second end section, the first end sections of each band element being in abutting relationship with each other and the second end sections of each band element being in abutting relationship with each other, the U-shaped intermediate section of each band element being spaced from one another, said first and second abutting end sections converging toward said spaced intermediate sections to define an opening spring angle between said first and second abutting end sections, said abutting first end sections being connected to said frame, said abutting second end sections having rotating means rotatably supporting said connecting shaft, said carriage means further comprising first wheel support means fixed to said shaft and rotatably supporting first wheel means for rotation about a first rotational axis, said first wheel support means comprising a pair of spaced support members each fixed to said shaft at two axially spaced locations on said shaft, said first wheel means comprising one wheel rotatably mounted on one of said spaced support members and another wheel mounted on the other of said spaced support members, and second wheel support means fixed to said shaft for rotatably supporting second wheel means for rotation about a second rotational axis, said second wheel support means comprising a pivotal shaft pivotably supporting said second wheel means for rotational movement about a third rotational axis, said third rotational axis being perpendicular to said first rotational axis, said second wheel support means further comprising a central support member fixed to said shaft at a generally central axial location of said shaft between said two axially spaced locations, said central support member pivotably supporting said pivotal shaft, said first and second wheels being moveable along two spaced paths of travel as said hand truck moves, said second wheel means being disposed between said two spaced paths.
Dependencies are inferred from the claim text.