1. A powered wheelchair comprising:
a frame;
a pair of opposing drives, each drive including a substantially-transversely mounted motor and gearbox;
a pair of drive wheels, each one of the drive wheels coupled to a corresponding one of the drives;
a power supply compartment that is generally located behind the drives, the compartment having a side opening through which a power supply may be removed, and
a chair supported on the frame such that the side opening of the compartment is accessible for power supply removal without removal of the chair from the frame.
2. The wheelchair of claim 1 wherein the power supply is batteries.
3. The wheelchair of claim 2 further comprising a cover having an first position in which cover is generally located over the side opening of the compartment and a second position in which the cover is spaced apart from the side opening to enable access thereto.
4. The wheelchair of claim 3 wherein the cover is removable from the compartment.
5. The wheelchair of claim 3 wherein the compartment has an upwardly extending lip on its lower edge proximate the side opening.
6. The wheelchair of claim 3 wherein a cover includes a panel portion that is approximately the same size as the side opening.
7. The wheelchair of claim 5 wherein cover has a groove on its lower edge, and the groove engages the lip while the cover is in its first position.
8. The wheelchair of claim 2 wherein the batteries are generally located to the rear of the drives.
9. The wheelchair of claim 2 wherein the gearbox is a single reduction gearbox.
10. The wheelchair of claim 2 wherein every portion of the batteries is located to the rear of the centerline of the drive wheel axis.
11. The wheelchair of claim 8 wherein every portion of the batteries is located to the rear of the drives.
12. The wheelchair of claim 2 wherein the chair is supported on the frame by a single post to which the chair assembly is mounted.
13. The wheelchair of claim 12 wherein the support is a post that attaches to the frame at a point that is behind a centerline of the drives.
14. The wheelchair of claim 12 wherein the support is a post that attaches to the frame at a point that is rearward of a centerline of the drives and forward of a compartment.
15. The wheelchair of claim 2 further comprising a pair of front wheels and at least one rear wheel.
16. The wheelchair of claim 15 wherein the front wheels are castors.
17. The wheelchair of claim 15 wherein the front wheels are anti-tip wheels that are suspended from a ground surface while the wheelchair is at rest.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. An imaging lens substantially consisting of six lenses of a negative first lens, a negative second lens, a positive third lens, a positive fourth lens, a negative fifth lens and a positive sixth lens in this order from an object side,
wherein an object-side surface of the second lens has a shape having negative refractive power at a center, and including a part having positive refractive power in an area between the center and an effective diameter edge, and having negative refractive power at the effective diameter edge, and the refractive power at the effective diameter edge being weaker than the refractive power at the center, and
wherein an object-side surface of the third lens is convex toward the object side, and
wherein the following conditional formulas (17-4), (14-3) and (20) are satisfied:
\u22123.5<f123f<\u22121.0\u2003\u2003(17-4);
0.5\u2266(R3+R4)(R3\u2212R4)\u22660.80\u2003\u2003(14-3); and
1.0<f4f<4.0\u2003\u2003(20), where
f123: a combined focal length of the first lens, the second lens and the third lens,
f: a focal length of an entire system,
R3: a curvature radius of an object-side surface of the second lens,
R4: a curvature radius of an image-side surface of the second lens, and
f4: a focal length of the fourth lens.
2. The imaging lens, as defined in claim 1, wherein the following conditional formula (11) is satisfied:
9<Lf<16\u2003\u2003(11), where
L: a length from an object-side surface of the first lens to an image plane on an optical axis when a back focus portion is a distance in air, and
f: a focal length of an entire system.
3. The imaging lens, as defined in claim 2, wherein the following conditional formula (11-3) is satisfied:
12.5<Lf<15.0\u2003\u2003(11-3), where
L: a length from an object-side surface of the first lens to an image plane on an optical axis when a back focus portion is a distance in air, and
f: a focal length of an entire system.
4. The imaging lens, as defined in claim 1, wherein the following conditional formula (12) is satisfied:
1<Bff<3\u2003\u2003(12), where
Bf: a length from an image-side surface of a most image-side lens to an image plane on an optical axis when the length is a distance in air, and
f: a focal length of an entire system.
5. The imaging lens, as defined in claim 4, wherein the following conditional formula (12-2) is satisfied:
1.7<Bff<2.3\u2003\u2003(12-2), where
Bf: a length from an image-side surface of a most image-side lens to an image plane on an optical axis when the length is a distance in air, and
f: a focal length of an entire system.
6. The imaging lens, as defined in claim 1, wherein the following conditional formula (13) is satisfied:
vd3+vd5<50.0\u2003\u2003(13), where
vd3: an Abbe number of the material of the third lens for d-line, and
vd5: an Abbe number of the material of the fifth lens for d-line.
7. The imaging lens, as defined in claim 6, wherein the following conditional formula (13-2) is satisfied:
38.0<vd3+vd5<48.0\u2003\u2003(13-2), where
vd3: an Abbe number of the material of the third lens for d-line, and
vd5: an Abbe number of the material of the fifth lens for d-line.
8. The imaging lens, as defined in claim 1, wherein the following conditional formula (15) is satisfied:
\u221210\u2266(R5+R6)(R5\u2212R6)\u2266\u22121\u2003\u2003(15), where
R5: a curvature radius of an object-side surface of the third lens, and
R6: a curvature radius of an image-side surface of the third lens.
9. The imaging lens, as defined in claim 8, wherein the following conditional formula (15-3) is satisfied:
\u22123.5\u2266(R5+R6)(R5\u2212R6)\u2266\u22121.3\u2003\u2003(15-3), where
R5: a curvature radius of an object-side surface of the third lens, and
R6: a curvature radius of an image-side surface of the third lens.
10. The imaging lens, as defined in claim 1, wherein the following conditional formula (16) is satisfied:
1.1\u2266(R1+R2)(R1\u2212R2)\u22663.0\u2003\u2003(16), where
R1: a curvature radius of an object-side surface of the first lens, and
R2: a curvature radius of an image-side surface of the first lens.
11. The imaging lens, as defined in claim 10, wherein the following conditional formula (16-2) is satisfied:
1.3\u2266(R1+R2)(R1\u2212R2)\u22662.0\u2003\u2003(16-2), where
R1: a curvature radius of an object-side surface of the first lens, and
R2: a curvature radius of an image-side surface of the first lens.
12. The imaging lens, as defined in claim 1, wherein the following conditional formula (17-3) is satisfied:
\u22123.2<f123f<\u22121.8\u2003\u2003(17-3), where
f123: a combined focal length of the first lens, the second lens and the third lens, and
f: a focal length of an entire system.
13. The imaging lens, as defined in claim 1, wherein the following conditional formula (18) is satisfied:
2<f3f<12\u2003\u2003(18), where
f3: a focal length of the third lens, and
f: a focal length of an entire system.
14. The imaging lens, as defined in claim 13, wherein the following conditional formula (18-3) is satisfied:
3.5<f3f<10\u2003\u2003(18-3), where
f3: a focal length of the third lens, and
f: a focal length of an entire system.
15. The imaging lens, as defined in claim 1, wherein the following conditional formula (19) is satisfied:
0.01<D9f<0.5\u2003\u2003(19), where
D9: an air space between the fourth lens and the fifth lens on an optical axis, and
f: a focal length of an entire system.
16. The imaging lens, as defined in claim 15, wherein the following conditional formula (19-1) is satisfied:
0.05<D9f<0.3\u2003\u2003(19-1), where
D9: an air space between the fourth lens and the fifth lens on an optical axis, and
f: a focal length of an entire system.
17. The imaging lens, as defined in claim 1, wherein the following conditional formula (20-1) is satisfied:
1.5<f4f<3.0\u2003\u2003(20-1), where
f4: a focal length of the fourth lens, and
f: a focal length of an entire system.
18. The imaging lens, as defined in claim 1, wherein the following conditional formula (21) is satisfied:
2.5<ER1f<7.5\u2003\u2003(21), where
ER1: an effective radius of an object-side surface of the first lens, and
f: a focal length of an entire system.
19. The imaging lens, as defined in claim 18, wherein the following conditional formula (21-1) is satisfied:
2.5<ER1f<8\u2003\u2003(21-1), where
ER1: an effective radius of an object-side surface of the first lens, and
f: a focal length of an entire system.
20. The imaging lens, as defined in claim 18, wherein the following conditional formula (21-4) is satisfied:
4.0<ER1f<6.5\u2003\u2003(21-4), where
ER1: an effective radius of an object-side surface of the first lens, and
f: a focal length of an entire system.
21. The imaging lens, as defined in claim 1, wherein a stop is arranged between the third lens and the fourth lens.
22. An imaging apparatus comprising:
the imaging lens, as defined in claim 1, mounted thereon.