Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
189 words
A pump mechanism for delivering ink or the like writing fluid from a reservoir to a writing device comprising a pump housing having an internal cylinder wall forming a cylinder, a piston disposed within said cylinder and slidable forward in a pumping stroke and backward in a suction stroke, and drive means for moving said piston through said pumping and suction strokes, said cylinder wall comprising a frusto-conical portion tapered inwardly in a direction away from said piston, and said piston comprising a plastic member having a forward end portion which cooperates with said tapered portion of said cylinder wall and which has an outside diameter which is greater than the smallest diameter of said tapered cylinder wall portion to slidingly engage the same in sealing relation as said piston moves forward during a pumping stroke, and to move out of engagement with the same as the piston moves backward in a suction stroke, said forward end portion of said piston having a forward facing recess formed therein permitting radially inward deformation of said forward end portion of said piston upon engagement thereof with said tapered cylinder wall portion.
Claim 2
Dependent Claim
189 words
A pump mechanism for delivering ink or the like writing fluid from a reservoir to a writing device comprising a pump housing having an internal cylinder wall forming a cylinder, a piston disposed within said cylinder and slidable forward in a pumping stroke and backward in a suction stroke, and drive means for moving said piston through said pumping and suction strokes, said cylinder wall comprising a frusto-conical portion tapered inwardly in a direction away from said piston, and said piston comprising a plastic member having a forward end portion which cooperates with said tapered portion of said cylinder wall and which has an outside diameter which is greater than the smallest diameter of said tapered cylinder wall portion to slidingly engage the same in sealing relation as said piston moves forward during a pumping stroke, and to move out of engagement with the same as the piston moves backward in a suction stroke, said forward end portion of said piston having a forward facing recess formed therein permitting radially inward deformation of said forward end portion of said piston upon engagement thereof with said tapered cylinder wall portion.
Claim 3
Dependent Claim
30 words
The invention as defined in claim 1 and including a flexible membrane disposed within said cylinder and fixedly connected to said piston and to said housing for partitioning said cylinder.
Claim 4
Dependent Claim
41 words
The invention as defined in claim 1 and including chamber forming means forming a chamber in communication with one end of said cylinder located forward of said tapered cylinder wall portion, said chamber forming means comprising a spring biased wall member.
Claim 5
Dependent Claim
43 words
The invention as defined in claim 1 wherein said drive means comprises a motor driven rotatable cam member having a cam groove formed therewithin, a cam follower disposed within said groove and a piston rod drivingly interconnecting said cam follower and said piston.
Claim 6
Dependent Claim
35 words
The invention as defined in claim 4 wherein said cam and cam groove are constructed and arranged so that the speed of said piston during a pumping stroke is greater than during a suction stroke.
Claim 7
Dependent Claim
38 words
The invention as defined in claim 1 and including a reservoir for containing a supply of writing fluid, and a capillary tube interconnecting said reservoir and said cylinder for delivering writing fluid from the former to the latter.
Claim 8
Dependent Claim
15 words
The invention as defined in claim 6 wherein said capillary tube is made of glass.