US3601234A

US3601234A - Microtome electric drive

Info

Publication number: US3601234A
Application number: US847051A
Authority: US
Inventors: Chester S Ingraham
Original assignee: American Optical Corp
Current assignee: Leica Microsystems Inc
Priority date: 1969-08-04
Filing date: 1969-08-04
Publication date: 1971-08-24
Anticipated expiration: 1988-08-24

Abstract

A microtome having an electric drive in conjunction with its hand wheel by which the microtome can be driven continuously or cyclically as well as by hand.

Description

United States Patent Inventor Appl. No.

Filed Patenied Assignee Chester S. Iugraham East Aurora, N.Y.

Aug. 4, 1969 Aug. 24, 1971 American Optical Corporation Sonthbridge, Mass.

MICROTOME ELECTRIC 011m 4 Chins, 3 Drawing Figs.

74/199, 74/354, 74/405, 83/9155, 192/142 R Fl6d 71/00 Field of Search Int. Cl.

[56] References Cited UNITED STATES PATENTS 2,175,086 10/1939 Mitchell 74/405 X 2,525,915 10/1950 Kuhn 74/405 X 3,021,719 2/1962 Conrad, Jr 74/405 X 2,500,956 3/1950 Mershon 192/.02 X 3,094,882 6/1963 l92/.02 X 3,120,298 2/1964 192/.02 3,131,456 5/1964 Bryant 192/142)( Primary Examiner-Allan D. Herrmann Attorneys-William C. Nealon, Noble S. Williams and Robert J. Bird ABSTRACT: A microtome having an electric drive in conjunction with its hand wheel by which the microtome can be driven continuously or cyclically as well as by hand.

PATENTED AUB24 IQTI SHEET 2 OF 2 lllll I'll illll ll iiiiiiiiiiii ii'i? INVENTOR. CHESTER S. INGRAHAM BY @LQ ATTO RNE Y In the drawing:

MICROTOME ELECTRIC DRIVE- BACKGROUND OF THE INVENTION nected to permit manual operation. Another characteristic of suchprior art mechanized microtome drives it that they have no provision for automatic stopping at the end of a cycle.

It is an object of the present invention to provide a mechanized microtome drive which permits selectively three modes of operation of the machine, these being continuous reciprocating motion, single cycle reciprocation, and free handwheel operation.

Another object is to provide a mechanized microtome 1 eliminating belts or other positive connection between motor and hand wheel, thus permitting greater ease of manual operation when desired.

Other objects, advantages and features of the present invention will become apparent from the following description of one embodiment thereof, when taken in connection with the accompanying drawing.

SUMMARY OF THE INVENTION Briefly, the present invention is practiced in one form by a microtome having a driving hand wheel which is disposed relative to a friction driving the microtome. This friction driving gear is motor driven and is movable into and away from driving engagement with the hand wheel by means of a solenoid actuator. The bracket in which the driving gear swings relative to the hand wheel is jointed and spring loaded to permit proper solenoid operation and to provide a biasing force of the gear against the wheel.

DRAWINGS FIG. 1 is an elevation, party in section, of a microtome electric drive according to the present invention;

.FIGLZ is a partial side elevation, party in section, of the apparatus shown in FIG. I; and

FIG. 3 is a wiring diagram of the microtome electric drive shown in FIG. 1.

DESCRIPTION Referring now to FIG. 1, a drive arrangement for a microtome is shown with the associated microtome simply represented by a partial showing of its driving handwheel 2. The hand wheel 2 is characterized by a grooved periphery as indicated'by the wheel's outside diameter 4 and the base of the groove shown at 6. Hand wheel 2 is disposed in a fixed position relative to a frame, generally indicated at 8 on which the electric drive mechanism of the present invention is also mounted. Referring now to FIG. 2, a driving motor 10 is mounted relative to frame 8 and is operatively connected through a gear reduction unit, generally indicated at 12, to a gear box shaft 14. Motor 10 is preferably a variable speed motor, but for simplicity, the circuit diagram has not included this feature.

Referring back to FIG. 1, gear box shaft 14 is fastened to a transmission spur gear 16.Transmission gear 16 meshes with a second transmission spur gear 18. Gears l6 and 18 are mounted on fixed axes relative to frame 8. The axis 20 of gear 18 also has rotatably mounted thereto a gear carrier 22. Carrier 22 supportsrotatable spindle 24 at its opposite extremity. A

transmission pinion 26 is fixedly mounted on spindle 24 on one side of carrier 22 and meshes with transmission gear 18. A"

friction drive gear or wheel28 is also fixedly mounted on spindle 24, on the opposite side of carrier 22 from the pinion 26. Thus, wheel 28 and pinion 26 are rotatable together. Carrier 22 is rigidly connected to an arm 34, members 22 and 34 together making up an integral swing bracket 32. The totality of swing bracket 32 is a second class lever with its fulcrum at 20 and its load at 24.

Arm 34 itself supports a spindle 36 and an abutment member 38, both members extending from arm 34 in the same direction. A second swing member or arm 40 is connected to swing bracket 32 and is rotatably mounted relative thereto on shaft 36. Arm 40 defines an aperture 42 through which abutment 38 extends. Abutment 38 and aperture 42 permit limited rotation of arm 40 relative to arm 34. Arm 40 and arm 34 are are mounted on frame 8. Normally open switch 50 has an actuation lever 54 extending therefrom and in contact with plunger 46 of solenoid 48. Normally closed switch 52 similarly has an actuation lever 56 which is disposed in operative rela-- tionship to a cam or abutment 58 mounted on hand wheel 2. Preferably a suitable linkage is interposed between cam 58 and lever 56, as indicated by lever member 60 which is rotatably mounted relative to frame 8 on a shaft 62. In this way, lever 56 and abutment 58 are in direct operative relationship.

Referring now to FIG. 3, the electrical wiring diagram for the present microtome drive system is shown. It includes a manually operated, normally open foot switch 64. This switch, incidentally, is not shown in the other views. Foot switch 64 is shown operatively connected to a source of line current 66 and also to a master switch 68, the closing of which is inclosed switch 52.

OPERATION The operation of the above-described apparatus will now be described. First, master switch 68 is closed to arm the circuit. The depression or closing of the foot switch 64 allows current to energize solenoid 48 and motor 10. The energizing of solenoid 48 moves its plunger to the right, closing the normally open switch 50. The closing of switch 50 renders the depression of foot pedal 64 no longer necessary. At the same time that solenoid plunger 46 actuates or closes switch 50, it pulls arm 40 and swing bracket 32 to the right, such that drive wheel 28 contacts hand wheel 2 in frictional engagement. The starting of motor 10 which drives wheel 28, and the solenoidactuated clutching of wheel 28 to microtome hand wheel 2, are substantially simultaneous operations. With the foot switch 64 having been momentarily depressed and released, the microtome and its associated hand wheel are now going through a single cycle. When hand wheel 2 completes one revolution, the cam or abutment 58 projecting therefrom trips or opens the normally closed switch 52. The opening of switch 52 opens the circuit, deenergizing solenoid 48 and shutting off motor 10. This pulls drive wheel.28 from wheel 2 and this enables the motor 10 and drive wheel 28 to coast to a stop without affecting the position of wheel 2. Thus, the microtome has gone through one complete cycle by a momentary depression of switch 64 and then stopped automatically. If foot switch 64 is held closed, the unit will run continuously.

It will be appreciated that, if swing bracket 32 and arm 40 were a single rigid member, there would be three possible effects. First, if drive wheel 28 were to contact hand wheel 22 before the solenoid plunger 46 was bottomed, the solenoid would be likely to hum or clatter. Secondly, there might be perfect coincidence between the contacting of wheel 28 to wheel 2 and the bottoming of plunger 46, but this might or might not provide good biasing force of the wheel 28 to the wheel 2. Thirdly, it would be possible that solenoid plunger 46 would bottom before wheel 28 made contact with wheel 2. All of these situations are undesirable, and for that reason the compound linkage member including swing bracket 32 and arm 40 is provided. It will be appreciated that when the solenoid is energized, arm 40 will swing the bracket 32 so that wheel 28 contacts wheel 2. The dimensions are not critical in the present invention, however, because arm 40 is, to a small degree, rotatable relative to bracket 32. This enables solenoid plunger 46 to bottom, with spring member 44 exerting a constant biasing force of friction wheel 28 on the hand wheel 2. When the circuit is opened and the solenoid plunger releases the engagement of wheel 28 and wheel 2, the spring 44 provides sufficient force to arm 40 and swing bracket 32 to insure that wheel 28 is swung away from wheel 2.

It will be apparent that a microtome driving mechanism has been provided by the present invention which permits an operator to use the machine in any of three modes of operation. That is, the machine is capable of continuous cycling or single cycling with automatic stopping, both these modes in connection with the electric drive. Thirdly, the drive mechanism disengages itself from hand wheel 2 to permit free hand operation.

It may occur to others of ordinary skill in the art to make modifications of the present invention which will lie within the concept and scope thereof and not constitute a departure therefrom. Accordingly, it is intended that the invention be not limited by the details in which it has been described, but only by the following claims.

lclaim:

1. An electric drive for a rotatable member (2) including:

a frame,

a drive motor,

a gear train operatively disposed relative to said motor and including a drive gear,

said drive gear being mounted on a pivoted lever linkage and being swingable therewith into driving position and engagement with said rotatable member (2) and away from said engagement to an idle position,

said lever linkage being operatively connected to a solenoid plunger to motivate the swing of said lever linkage relative to said rotatable member (2), the idle position of said drive gear corresponding to the deenergized state of said solenoid,

said linkage including a bracket which is pivoted to said frame and carries said drive gear, an arm extending from said bracket and being connected to said plunger, said bracket and arm being articulated for limited relative rotational movement, means to limit the rotation of said arm relative to said bracket, and means biasing said bracket relative to said arm toward said driving position,

said drive motor and said solenoid being electrically connected to a common circuit.

2. An electric drive for a rotatable member according to claim 1 and further including:

a control circuit operatively connectedto said motor and said solenoid and including a manual switch to control energization thereof,

a normally closed switch actuable in response to a position of said rotatable member (2) to control a deenergization of the circuit,

the energized state of said circuit effecting the driving engagement of said drive gear and said rotatable member.

3. An electric drive for a rotatable member according to claim 1 and further including:

a cam mountedpn said rotatable member, a control circuit operatively connected to said motor and said solenoid and including a manual switch to control energization thereof,

a normally open switch actuable by the movement of said solenoid plunger in response to energization and, upon such actuation, effective to hold said circuit closed independently of said manual switch,

a normally closed switch actuable by contact with said cam and, upon such actuation, effective to open said circuit,

4. An electric drive for a rotatable member according to claim 3 in combination with a microtome, said rotatable member being the handwheel of said microtome.

Claims

1. An electric drive for a rotatable member (2) including: a frame, a drive motor, a gear train operatively disposed relative to said motor and including a drive gear, said drive gear being mounted on a pivoted lever linkage and being swingable therewith into driving position and engagement with said rotatable member (2) and away from said engagement to an idle position, said lever linkage being operatively connected to a solenoid plunger to motivate the swing of said lever linkage relative to said rotatable member (2), the idle position of said drive gear corresponding to the deenergized state of said solenoid, said linkage including a bracket which is pivoted to said frame and carries said drive gear, an arm extending from said bracket and being connected to said plunger, said bracket and arm being articulated for limited relative rotational movement, means to limit the rotation of said arm relative to said bracket, and means biasing said bracket relative to said arm toward said driving position, said drive motor and said solenoid being electrically connected to a common circuit.

2. An electric drive for a rotatable member according to claim 1 and further including: a control circuit operatively connected to said motor and said solenoid and including a manual switch to control energization thereof, a normally closed switch actuable in response to a position of said rotatable member (2) to control a deenergization of the circuit, the energized state of said circuit effecting the driving engagemEnt of said drive gear and said rotatable member.

3. An electric drive for a rotatable member according to claim 1 and further including: a cam mounted on said rotatable member, a control circuit operatively connected to said motor and said solenoid and including a manual switch to control energization thereof, a normally open switch actuable by the movement of said solenoid plunger in response to energization and, upon such actuation, effective to hold said circuit closed independently of said manual switch, a normally closed switch actuable by contact with said cam and, upon such actuation, effective to open said circuit, the energized state of said circuit effecting the driving engagement of said drive gear and said rotatable member.