US3921971A — Suction device for separating and/or transporting…

Claim 1

Independent Claim 503 words

In a sheet-handling machine, a suction device for engaging and then holding sheets, comprising, in combination, a pneumatic cylinder; a hollow piston units in said cylinder movable between a retracted and a non-retracted position and comprised of axially adjacent first and second portion, at least a part of the circumferential periphery of each of said portions being spaced from and out of contact with the inner periphery of said cylinder to define therewith respective first and second spaces, said piston unit including a sheet-engaging portion having a suction opening which communicates with the ambient atmosphere and constitutes the end of the hollw interior of said piston unit, said hollow interior communicating with said second space via said first space, said cylinder being provided with a suction port opening into said second space to form a path for the flow of ambient air into said suction opening and out through said port, the flow cross section of said first space being smaller than that of said second space so that said first space constitutes a flow restriction in said path; and drive means for causing said piston unit to move from retracted to non-retracted position and then back to retracted position, in order to cause said sheet-engaging portion to move into engagement with a sheet located in the path of movement of the latter and then hold said sheet by suction during the movement of said piston unit back to said retracted position, said drive means comprising suction-generating means connected to said port and operative for establishing subambient pressure in said second space, whereby said piston moves from said retracted to said non-retracted position upon the establishment of such subambient pressure as a result of the initial difference in pressures upstream and downstream of said first space, and whereby said piston returns to said retracted position due to the pressure equalization resulting when the sheet engaged and held by said sheet-engaging portion blocks further entrance of ambient air into said suction opening of the said sheet-engaging portion, wherein said first portion of said piston unit is cylindrical and constitutes a hollow piston portion and wherein said second portion of said piston unit is cylindrical and constitutes a hollow piston rod portion, and wherein said hollow piston portion is spaced from and out of contact with the inner periphery of said cylinder all around the circumferential periphery of said hollow piston portion, whereby there is no frictional wear of the circumferential surface of said piston portion and the facing inner surface of said cylinder, and wherein said cylinder is further provided with an axially extending guide portion for guiding said piston Rod portion, said guide portion having an axial end portion facing said piston portion, and wherein said piston rod portion is further provided with a recess constituting a suction release passage having one end opening into the ambient atmosphere and having another end which terminates just past said axial end portion of said guide portion when said piston unit is in said retracted position.

Claim 2

Dependent Claim 503 words

In a sheet-handling machine, a suction device for engaging and then holding sheets, comprising, in combination, a pneumatic cylinder; a hollow piston units in said cylinder movable between a retracted and a non-retracted position and comprised of axially adjacent first and second portion, at least a part of the circumferential periphery of each of said portions being spaced from and out of contact with the inner periphery of said cylinder to define therewith respective first and second spaces, said piston unit including a sheet-engaging portion having a suction opening which communicates with the ambient atmosphere and constitutes the end of the hollw interior of said piston unit, said hollow interior communicating with said second space via said first space, said cylinder being provided with a suction port opening into said second space to form a path for the flow of ambient air into said suction opening and out through said port, the flow cross section of said first space being smaller than that of said second space so that said first space constitutes a flow restriction in said path; and drive means for causing said piston unit to move from retracted to non-retracted position and then back to retracted position, in order to cause said sheet-engaging portion to move into engagement with a sheet located in the path of movement of the latter and then hold said sheet by suction during the movement of said piston unit back to said retracted position, said drive means comprising suction-generating means connected to said port and operative for establishing subambient pressure in said second space, whereby said piston moves from said retracted to said non-retracted position upon the establishment of such subambient pressure as a result of the initial difference in pressures upstream and downstream of said first space, and whereby said piston returns to said retracted position due to the pressure equalization resulting when the sheet engaged and held by said sheet-engaging portion blocks further entrance of ambient air into said suction opening of the said sheet-engaging portion, wherein said first portion of said piston unit is cylindrical and constitutes a hollow piston portion and wherein said second portion of said piston unit is cylindrical and constitutes a hollow piston rod portion, and wherein said hollow piston portion is spaced from and out of contact with the inner periphery of said cylinder all around the circumferential periphery of said hollow piston portion, whereby there is no frictional wear of the circumferential surface of said piston portion and the facing inner surface of said cylinder, and wherein said cylinder is further provided with an axially extending guide portion for guiding said piston Rod portion, said guide portion having an axial end portion facing said piston portion, and wherein said piston rod portion is further provided with a recess constituting a suction release passage having one end opening into the ambient atmosphere and having another end which terminates just past said axial end portion of said guide portion when said piston unit is in said retracted position.

Claim 3

Dependent Claim 422 words

In a sheet-handling machine, a suction device for engaging and then holding sheets, comprising, in combination, a pneumatic cylinder; a hollow piston unit in said cylinder movable between a retracted and a non-retracted position and comprised of axially adjacent first and second portions, at least a part of the circumferential periphery of each of said portions being spaced from and out of contact with the inner periphery of said cylinder to define therewith respective first and second spaces, said piston unit including a sheet-engaging portion having a suction opening which communicates with the ambient atmosphere and constitutes the end of the hollow interior of said piston unit, said hollow interior communicating with said second space via said first space, said cylinder being provided with a suction port opening into said second space to form a path for the flow of ambient air into said suction opening and out through said port, the flow cross section of said first space being smaller than that of said second space so that said first space constitutes a flow restriction in said path; and drive means for causing said piston unit to move from retracted to non-retracted position and then back to retracted position, in order to cause said sheet-engaging portion to move into engagement with a sheet located in the path of movement of the latter and then hold said sheet by suction during the movement of said piston unit back to said retracted position, said drive means comprising suctiongenerating means connected to said port and operative when activated for establishing subambient pressure in said second space, whereby said piston unit moves from said retracted to said non-retracted position upon the establishment of such subambient pressure as a result of the initial difference in pressures upstream and downstream of said first space, and whereby said piston unit returns to said retracted position due to the pressure equalization resulting when the sheet engaged and held by said sheet-engaging portion blocks further entrance of ambient air into said suction opening of said sheet-engaging portion, the hollow interior of said piston unit and the part of the hollow interior of said cylinder external to said piston unit together forming when said suction opening is blocked by a sheet and said piston unit is in the retracted position a closed chamber sealed off from the ambient atmosphere to such an extent that the subambient pressure established in such a chamber by said suction-generating means maintains said piston unit in the retracted position indefinitely until said suction-generating means is deactivated.

Claim 4

Dependent Claim 422 words

In a sheet-handling machine, a suction device for engaging and then holding sheets, comprising, in combination, a pneumatic cylinder; a hollow piston unit in said cylinder movable between a retracted and a non-retracted position and comprised of axially adjacent first and second portions, at least a part of the circumferential periphery of each of said portions being spaced from and out of contact with the inner periphery of said cylinder to define therewith respective first and second spaces, said piston unit including a sheet-engaging portion having a suction opening which communicates with the ambient atmosphere and constitutes the end of the hollow interior of said piston unit, said hollow interior communicating with said second space via said first space, said cylinder being provided with a suction port opening into said second space to form a path for the flow of ambient air into said suction opening and out through said port, the flow cross section of said first space being smaller than that of said second space so that said first space constitutes a flow restriction in said path; and drive means for causing said piston unit to move from retracted to non-retracted position and then back to retracted position, in order to cause said sheet-engaging portion to move into engagement with a sheet located in the path of movement of the latter and then hold said sheet by suction during the movement of said piston unit back to said retracted position, said drive means comprising suctiongenerating means connected to said port and operative when activated for establishing subambient pressure in said second space, whereby said piston unit moves from said retracted to said non-retracted position upon the establishment of such subambient pressure as a result of the initial difference in pressures upstream and downstream of said first space, and whereby said piston unit returns to said retracted position due to the pressure equalization resulting when the sheet engaged and held by said sheet-engaging portion blocks further entrance of ambient air into said suction opening of said sheet-engaging portion, the hollow interior of said piston unit and the part of the hollow interior of said cylinder external to said piston unit together forming when said suction opening is blocked by a sheet and said piston unit is in the retracted position a closed chamber sealed off from the ambient atmosphere to such an extent that the subambient pressure established in such a chamber by said suction-generating means maintains said piston unit in the retracted position indefinitely until said suction-generating means is deactivated.

Claim 5

Dependent Claim 22 words

In a sheet-handling machine as defined in claim 2, wherein said first space is annular and wherein said second space is annular.

Claim 6

Dependent Claim 49 words

In a sheet-handling machine as defined in claim 2, wherein said first and second portions of said piston unit are cylindrical and coaxial, with the diameter of said first portion being larger than the diameter of said second portion, and wherein said first and second spaces are both annular.

Claim 7

Dependent Claim 50 words

In a sheet-handling machine as defined in claim 2, wherein at least one of said first and second portions of said piston unit is spaced from and out of contact with the inner periphery of said cylinder all around the circumferential periphery of said at least one of said portions.

Claim 8

Dependent Claim 42 words

In a sheet-handling machine as defined in claim 2, wherein at least said first portion of said piston unit is spaced from and out of contact with the inner periphery of said cylinder all around the circumferential periphery of said first portion.

Claim 9

Dependent Claim 42 words

In a sheet-handling machine as defined in claim 2, wherein at least said second portion of said piston unit is spaced from and out of contact with the inner periphery of said cylinder all around the circumferential periphery of said second portion.

Claim 10

Dependent Claim 21 words

In a sheet-handling machine as defined in claim 2, wherein said first space constitutes the only flow restriction in said path.

Claim 11

Dependent Claim 113 words

In a sheet-handling machine as defined in claim 2, wherein said cylinder is further provided with a suction release opening having a flow cross-sectional area so related to that of said second space and to the magnitude of said subambient pressure in said chamber that when a sheet engaged and held by said sheet-engaging portion blocks off said suction opening the loss of suction inside said hollow piston unit is insufficient to result in termination of the holding action, but so related to the volume of said second space that upon deactivation of said suction-generating means ambient air entering said suction release passage can quickly destroy the subambient pressure in said second space.

Claim 12

Dependent Claim 176 words

In a sheet-handling machine as defined in claim 2, wherein said first portion of said piston unit is cylindrical and constitutes a hollow piston portion and wherein said second portion of said piston unit is cylindrical and constitutes a hollow piston rod portion, and wherein said hollow piston portion is spaced from said out of contact with the inner periphery of said cylinder all around the circumferential periphery of said hollow piston portion, whereby there is no frictional wear of the circumferential surface of said piston portion and the facing inner surface of said cylinder, and wherein said cylinder is further provided with an axially extending guide portion for guiding said piston rod portion, said guide portion having an axial end portion facing said piston portion, and wherein said piston rod portion is further provided with a recess constituting a suction release passage having one end opening into the ambient atmosphere and having another end which terminates just past said axial end portions of said guide portion when said piston unit is in said retracted position.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1978-11-24	1979-05-26	1979-11-25	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1982-11-24	1983-05-26	1983-11-25	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1986-11-24	1987-05-26	1987-11-25	$7700.00	Window Closed / Lapsed

Suction device for separating and/or transporting sheets in a sheet-handling machine

Abstract

Inventors

Bibliographic Details

Claims Analysis

References Cited (Backward Citations)

USPTO Annuity & Maintenance Windows

Assigned Categories & Tags

Assign Category Tag