Boat hoist

Claim 2

A boat hoist, comprising: a support frame, means mounting said frame directly on the shore closely adjacent a body of water, an elongated boat support member disposed longitudinally over and above the body of water, said boat support member having respective inner and outer ends with said inner end being oriented in relatively close relationship to said support frame, an extensible and retractable arm assembly operatively secured at respective opposite ends to said support frame and to said inner end of said boat support member, means on said support frame operatively connected to said arm assembly to selectively effect the extension thereof away from the shore over and downwardly towards the water and the retraction thereof upwardly relative to the water and towards the shore and said support frame, the directional movements of said arm assembly relative to the water and shore effecting corresponding movements of said boat support member so that the extension of said arm assembly acts to project said boat support member in a direction away from the shore and into tHe water to a predetermined depth, and the retraction of said arm assembly acts to elevate said boat support member and move it in a direction toward the shore to a predetermined plane above the level of the water adjacent the shore.

Claim 3

A boat hoist as defined in claim 1 including: said support frame being vertically disposed, and means attaching said support frame on the shore to permit of its vertical adjustment relative to the level of an adjacent body of water.

Claim 4

A boat hoist as defined in claim 1 including: said arm assembly comprising: a scissor arm unit including a pair of elongated rigid arms pivotally connected at their longitudinal center and having their opposite ends operatively connected respectively to said support frame and said boat support member.

Claim 5

A boat hoist as defined in claim 1 including: said arm assembly comprising: a scissor arm unit including a pair of elongated rigid arms pivotally connected at their longitudinal center and having at each opposite extremity a pair of end members defining an upper end and a lower end which move in a substantially vertical plane during the extension and retraction of said scissor arm unit, said lower end at one extremity of said arm unit being pivotally secured to said support frame at a point above water level and said upper end at the corresponding extremity being slidably arranged relative to said support frame above said lower end, and said upper end at the other extremity of said arm unit being pivotally secured to said boat support member at a point above water level and said lower end at the corresponding extremity being slidably arranged relative to said boat support member below said upper end.

Claim 6

A boat hoist as defined in claim 4 including: said means on said support frame to effect the extension and retraction of said arm assembly comprising: a shaft mounted on said support frame for rotation about its longitudinal axis, a source of power for rotating said shaft in two respective opposite directions, a first cable means wound in one direction on said shaft and connected to said arm assembly adjacent said boat support member, and a second cable means wound in the opposite direction on said shaft and operatively connected to said upper end of said arm assembly adjacent said support frame whereby in one direction of rotation of said shaft, said second cable pulls said upper end of said scissor arm unit downwardly relative to said support frame to effect the extension of said scissor arm during which time said first cable means unwinds and in the reverse rotation of said shaft, said first cable means winds up to effect the retraction of said scissor arm unit with said second cable means unwinding to permit said upper end to move upwardly relative to said support frame.

Claim 7

A boat hoist as defined in claim 4 including: said means on said support frame to effect the extension and retraction of said arm assembly comprising: a block with a threaded bore having a vertical axis operatively connected to said upper end of said scissor arm unit relative to said support frame, a vertically disposed shaft on said support frame mounted for rotation about its longitudinal axis and threadably journalled in said block, and means on said support frame associated with said shaft to selectively rotate the same in two respective opposite directions whereby in one direction of rotation said upper end of said scissor unit is moved downwardly to effect the extension of said arm assembly and rotation of said shaft in the opposite direction moves said upper end upwardly to effect the retraction of said arm assembly.

Claim 8

A boat hoist as defined in claim 1 including: a vertically disposed first trackway on said support frame, the lower end of said trackway being fixed at a point above the level of the water, a second vertically disposed trackway carried by said boat support member, said arm assEmbly comprising: a scissor arm unit including a pair of elongated rigid arms pivotally connected at their longitudinal center and having at each opposite extremity a pair of end members defining an upper end and a lower end which move in a substantially vertical plane during the extension and retraction of said scissor arm unit, said lower end at one extremity of said scissor arm unit being pivotally secured to the lower end of said first trackway and said upper end at the corresponding extremity being slidably arranged relative to said trackway, said upper end at the other extremity of said scissor arm unit being pivotally secured to the upper end of said second trackway and said lower end at the corresponding extremity being slidably arranged relative to said trackway, the corresponding upper and lower ends of said scissor arm unit at respective opposite extremities being at all times planar with each other whereby with said arm assembly retracted, said upper end in said first trackway is at the upper end thereof and said lower end in said second trackway is at the lower end thereof and in the extension of said arm assembly, said upper end in said first trackway slides downwardly therein to effect a corresponding lowering of said second trackway and boat support member at which time said second trackway slidably moves downwardly relative to said lower end of said scissor arm unit therein so that said boat support member is progressively projected away from the shore line and into the water.

Claim 9

A boat hoist as defined in claim 7 including: means adjustably attaching said first trackway to said support frame to permit of its vertical adjustment thereon relative to the level of an adjacent body of water.