[CLAIMS]
[Claim 1]
An elevator diagnosing device comprising:
a hoisting machine having a sheave around which a middle portion of a main rope that suspends an elevator car is wound; and
control means configured to cause the elevator car to travel by controlling an operation of the hoisting machine, wherein
the control means includes:
car control means configured to perform first travel control that causes the elevator car to travel at a first acceleration/deceleration and second travel control that causes the elevator car to travel at a second acceleration/deceleration, the second acceleration/deceleration being less than the first acceleration/deceleration;
rope feed amount difference detection means configured to detect a difference in an amount of feed of the main rope by rotation of the sheave when the elevator car is caused to travel equal distances under the first travel control and under the second travel control; and
determination means configured to determine traction performance of the sheave, based on the difference in the amount of feed of the main rope detected by the rope feed amount difference detection means.

[Claim 2]
An elevator diagnosing device comprising:
a hoisting machine having a sheave around which a middle portion of a main rope that suspends an elevator car is wound; and
control means configured to cause the elevator car to travel by controlling an operation of the hoisting machine, wherein
the control means includes:
car control means configured to perform first travel control that causes the elevator car to travel with a first acceleration/deceleration time and second travel control that causes the elevator car to travel with a second acceleration/deceleration time, the second
acceleration/deceleration time being shorter than the first acceleration/deceleration time;
rope feed amount difference detection means configured to detect a difference in an amount of feed of the main rope by rotation of the sheave when the elevator car is caused to travel equal distances under the first travel control and under the second travel control; and
determination means configured to determine traction performance of the sheave, based on the difference in the amount of feed of the main rope detected by the rope feed amount difference detection means. [Claim 3]

The elevator diagnosing device according to Claim 1 or 2, wherein
the rope feed amount difference detection means detects the difference in the amount of feed of the main rope, based on a difference in the number of rotations of the sheave when the elevator car is caused to travel equal distances under the first travel control and under the second travel control. [Claim 4]
The elevator diagnosing device according to Claim 1 or 2, wherein
the rope feed amount difference detection means detects the difference in the amount of feed of the main rope, based on a difference in a rotational phase angle of the sheave when the elevator car is caused to perform reciprocal travel under the first travel control in one of one way and the other way of the reciprocal travel and under the second travel control in the other one of the one way and the other way of the reciprocal travel. [Claim 5]
The elevator diagnosing device according to Claim 3 or 4, further comprising:
an encoder configured to detect the number of rotations of the sheave and the rotational phase angle of the sheave, wherein
the rope feed amount difference detection means detects the difference in the amount of feed of the main rope by using a

detection result of the encoder. [Claim 6]
The elevator diagnosing device according to Claim 1 or 2, wherein
a rope-side mark is provided at a predetermined position of the main rope,
a sheave-side mark is provided at a predetermined position of the sheave, and
the rope feed amount difference detection means detects the difference in the amount of feed of the main rope, based on a change of relative positions of the rope-side mark and the sheave-side mark when the elevator car is caused to perform reciprocal travel under the first travel control in one of one way and the other way of the reciprocal travel and under the second travel control in the other one of the one way and the other way of the reciprocal travel. [Claim 7]
The elevator diagnosing device according to any one of Claims 1 to 6, wherein
the car control means causes the elevator car to travel at an acceleration/deceleration that is less than an acceleration/deceleration during a normal operation after determination is made that the traction performance of the sheave is lower than a predetermined reference by the determination

means. [Claim 8]
The elevator diagnosing device according to any one of Claims 1 to 7, wherein
the car control means causes the elevator car to travel at a maximum speed that is less than a maximum speed during the normal operation after determination is made that the traction performance of the sheave is lower than the predetermined reference by the determination means. [Claim 9]
The elevator diagnosing device according to any one of Claims 1 to 8, wherein
the first travel control and the second travel control by the car control means, the detection of the difference in the amount of feed of the main rope by the rope feed amount difference detection means, and the determination of the traction performance of the sheave by the determination means are performed during a preset time period in which an elevator is not used.