Torque limiter and sheet separating device having a torque limiter

Abstract

A torque limiter may include a first member configured to rotate about a first axis and having a first contact surface. The torque limiter may include a second member configured to rotate about the first axis and including a first axially extending finger. The first finger may be radially biased so that a second contact surface defined by the first finger may contact the first contact surface with a normal force to define a predetermined torque value between the first and second members. When one of the first and second members is rotatably driven in a first rotational direction, the other of the first and second members may be rotatably driven in the first rotational direction unless a torque load greater than or equal to the predetermined torque value is applied to the other of the first and second members.

1 . A torque limiter comprising:
 a first member configured to rotate about a first axis and having a first contact surface;   a second member configured to rotate about the first axis and including a first axially extending finger, wherein the first finger is radially biased so that a second contact surface defined by the first finger contacts the first contact surface with a normal force to define a predetermined torque value between the first and second members, whereby when one of the first and second members is rotatably driven in a first rotational direction, the other of the first and second members is rotatably driven in the first rotational direction unless a torque load greater than or equal to the predetermined torque value is applied to the other of the first and second members.   
   
   
       2 . The torque limiter according to  claim 1 , wherein the second member further comprises:
 a second axially extending finger radially separated from the first finger, wherein at least one of the first and second fingers includes the second contact surface; and   a radially oriented biasing member disposed between the first and second fingers, wherein the biasing member is configured to radially bias at least one of the first and second fingers so that the second contact surface contacts the first contact surface with the normal force to define the predetermined torque value between the first and second members.   
   
   
       3 . The torque limiter according to  claim 2 , wherein the biasing member comprises a coiled compression spring. 
   
   
       4 . The torque limiter according to  claim 1 , wherein the first member comprises a hollow sleeve and the first contact surface comprises an inner annular surface of the hollow sleeve defining a cavity, and wherein the second contact surface comprises an outer surface of the first finger and is configured to contact the inner annular surface of the first member when the second member is received in the cavity, and wherein the first finger is biased in a radially outward direction. 
   
   
       5 . The torque limiter according to  claim 2 , wherein the first member comprises a hollow sleeve and the first contact surface comprises an inner annular surface of the hollow sleeve defining a cavity, and wherein the second contact surface comprises an outer surface of at least one of the first and second fingers and is configured to contact the inner annular surface of the first member when the second member is received in the cavity, and wherein the biasing member is configured to bias at least one of the fingers in a radially outward direction. 
   
   
       6 . The torque limiter according to  claim 1 , wherein the first member comprises a plastic material. 
   
   
       7 . The torque limiter according to  claim 1 , wherein the first member comprises polyoxymethylene and glass fiber and a lubricant comprising PTFE. 
   
   
       8 . The torque limiter according to  claim 1 , wherein the second member comprises a plastic material. 
   
   
       9 . The torque limiter according to  claim 1 , wherein the second member comprises nylon 6/6 and a lubricant comprising silicone and PTFE. 
   
   
       10 . A sheet separating device comprising:
 an advancing roller configured to be driven by a drive device in a first rotational direction about a first axis to move a first sheet picked from a stack of sheets forward along a sheet path;   a reversing roller positioned adjacent to the advancing roller to define a nip therebetween and configured to be driven in the first rotational direction about a second axis to move a second sheet picked with the first sheet from the stack of sheets backwards along the sheet path, wherein the reversing roller is rotatably driven via a torque limiter comprising:
 a first member configured to rotate about the second axis and having a first contact surface; 
 a second member configured to rotate about the second axis and including a first axially extending finger, wherein the first finger is radially biased so that a second contact surface defined by the first finger contacts the first contact surface with a normal force to define a predetermined torque value between the first and second members, whereby when one of the first and second members is rotatably driven in the first rotational direction, the other of the first and second members is rotatably driven in the first rotational direction unless a torque load greater than or equal to the predetermined torque value is applied to the reversing roller. 
   
   
   
       11 . The sheet separating device according to  claim 10 , wherein the second member further comprises:
 a second axially extending finger radially separated from the first finger, wherein at least one of the first and second fingers includes the second contact surface; and   a radially oriented biasing member disposed between the first and second fingers, wherein the biasing member is configured to radially bias at least one of the first and second fingers so that the second contact surface contacts the first contact surface with the normal force to define the predetermined torque value between the first and second members.   
   
   
       12 . The sheet separating device according to  claim 11 , wherein the biasing member comprises a coiled compression spring. 
   
   
       13 . The sheet separating device according to  claim 10 , wherein at least one of the advancing roller and the reversing roller is linearly biased against the other in a direction perpendicular to the first and second axes. 
   
   
       14 . The sheet separating device according to  claim 10 , wherein when no sheets are received in the nip between the advancing roller and the reversing roller, the torque load applied to the reversing roller by the advancing roller is greater than the predetermined torque value of the torque limiter, whereby one of the first and second members rotates relative to the other of the first and second members and the reversing roller rotates in a second rotational direction opposite the first rotational direction. 
   
   
       15 . The sheet separating device according to  claim 10 , wherein when one sheet picked from the stack of sheets is received in the nip between the advancing roller and the reversing roller, the torque load applied to the reversing roller by the advancing roller via the one sheet is greater than the predetermined torque value of the torque limiter, whereby one of the first and second members rotates relative to the other of the first and second members and the reversing roller rotates in a second rotational direction opposite the first rotational direction to move the one sheet forward along the sheet path. 
   
   
       16 . The sheet separating device according to  claim 10 , wherein when two or more sheets picked from the stack of sheets are received in the nip between the advancing roller and the reversing roller, the torque load applied to the reversing roller by the advancing roller via the two or more sheets is less than the predetermined torque value of the torque limiter. 
   
   
       17 . The sheet separating device according to  claim 10 , wherein the first member comprises a hollow sleeve and the first contact surface comprises an inner annular surface of the hollow sleeve defining a cavity, and wherein the second contact surface comprises an outer surface of the first finger and is configured to contact the inner annular surface of the first member when the second member is received in the cavity, and wherein the first finger is biased in a radially outward direction. 
   
   
       18 . The sheet separating device according to  claim 11 , wherein the first member comprises a hollow sleeve and the first contact surface comprises an inner annular surface of the hollow sleeve defining a cavity, and wherein the second contact surface comprises an outer surface of at least one of the first and second fingers and is configured to contact the inner annular surface of the first member when the second member is received in the cavity, and wherein the biasing member is configured to bias at least one of the fingers in a radially outward direction. 
   
   
       19 . The sheet separating device according to  claim 10 , wherein the first member comprises a plastic material. 
   
   
       20 . The sheet separating device according to  claim 10 , wherein the first member comprises polyoxymethylene and glass fiber and a lubricant comprising PTFE. 
   
   
       21 . The sheet separating device according to  claim 10 , wherein the second member comprises a plastic material. 
   
   
       22 . The sheet separating device according to  claim 10 , wherein the second member comprises nylon 6/6 and a lubricant comprising silicone and PTFE. 
   
   
       23 . A sheet separating device comprising:
 first means for moving a first sheet picked from a stack of sheets forward along a sheet path;   second means for moving a second sheet picked with the first sheet from the stack of sheets backwards along the sheet path;   means for driving the first means and the second means; and   means for limiting torque applied to the second means by the driving means, wherein the torque limiting means defines a predetermined torque value, whereby the second means is driven by the driving means to move the second sheet backwards along the sheet path unless a torque load greater than or equal to the predetermined torque value is applied to the second means.