Laboratory clock

Claim 2

In a timer including a motor, a pointer driven by the motor through a transmission gear train, the pointer being settable to a predetermined position representing a desired time interval, a start lever for actuating the motor in such a manner that the pointer runs toward a zero position from the predetermined position and a trip mechanism for actuating a stop lever when the pointer has run back to the zero position to stop the motor, the improvement comprising: switch means for selectively changing the direction of travel of the pointer through the gear train so that the pointer runs away from the zero position, the switch means being coupled to the trip mechanism to prevent the actuation of the stop lever by the trip mechanism when the pointer runs away from the zero position; and means for manually actuating the stop lever so that the motor can be stopped when the pointer runs away from the zero position, whereby the timer is operable as a stop watch.

Claim 3

A timer according to claim 1, further comprising a program disc mounted for movement with the pointer, adjustable tabs mounted on the program disc for preselecting desired time intervals, and a pin connected to the stop lever in such a manner that the pin protrudes into the path of the tabs as the program disc moves with the pointer so that the tabs actuate the stop lever when any one of the tabs engages the pin.

Claim 4

A timer according to claim 2, wherein the pin is integral with the stop lever.

Claim 5

A timer according to claim 2, wherein the program disc is releasably mounted for movement with the pointer.

Claim 6

A timer according to claim 4, further comprising a rotatable shaft, the pointer being mounted on the shaft for rotation therewith; a program disc wheel mounted on the shaft for rotation therewith and having a key projecting therefrom; and a radial slit in the program disc releasably engaging the key of the program disc wheel.

Claim 7

A timer according to claim 2, wherein the tabs are removably mounted on the outer edge of the program disc.

Claim 8

A timer according to claim 2, further comprising an oblong hole in the stop lever and a pivot pin extending through the oblong hole in such a manner that the oblong hole slides over the pivot pin to move the stop lever between a first position occupied by the stop lever when the motor is deactivated and a second position occupied by the stop lever when the motor is actuated, the first and second positions being located in relation to the program disc such that the pin on the stop lever protrudes into the path of the tabs on the program disc only when the stop lever occupies the second position.

Claim 9

A timer according to claim 7, further comprising a rotatable shaft, the pointer being mounted on the shaft for rotation therewith, and means for mounting the pin on the stop lever in such a manner that the pin pivots in one direction so that when the program disc rotates in the opposite direction any one of the tabs engaging the pin pivots the pin in the one direction away from the tab, whereby the stop lever is prevented from being actuated by the tabs when the pointer rotates in the opposite direction.

Claim 10

A timer according to claim 1, further comprising spring means for biasing the start lever into a rest position occupied by the start lever when the motor is stopped; and catch means, acting after the start lever has been moved out of the rest position and into an operating position in which the motor is actuated, for preventing the spring means from drawing the start lever back into the rest position until the stop lever is actuated by the trip mechanism.

Claim 11

A timer according to claim 9, wherein the catch means includes a lug on the stop lever and a projection on the start lever, the projection releasably engaging the lug when the start lever is in the operating position.

Claim 12

A timer according to claim 10, wherein the trip mechanism includes a trip lever having a cog, a disc mounted for movement with the pointer and having a recess on an outer edge, the trip lever and the disc being positioned such that the cog of the trip lever slides along the outer edge of the disc as the pointer runs back toward the zero position and mates with the recess in the disc when the pointer has run back to zero position to disengage the lug of the stop lever form the projection of the start lever so that the start lever is drawn back into the rest position by the spring means.

Claim 13

A timer according to claim 11, further comprising a second pointer driven by the motor through the transmission gear train, the second pointer being mounted for movement with the other pointer at an increased rate of speed to measure a time interval of smaller units, a second disc mounted for movement with the second pointer and having a recess on an outer edge, the second disc being positioned such that the cog of the trip lever slides along the outer edge of the second disc as the pointer runs back toward the zero position and mates with the recess in the second disk when the pointer has run back to the zero position to disengage the lug of the stop lever from the projection of the start lever so that the start lever is drawn back into the rest position by the spring means.

Claim 14

A timer according to claim 12, further comprising a notched disc mounted for movement with the second pointer and having a pair of notches on an outer edge, a follower lever positioned to slide along the outer edge of the notched disc as the second pointer moves with the other pointer and engage one of the notches when the second pointer reaches a predetermined position, and detent means for preventing the lug of the stop lever from disengaging the cog of the start lever until the follower lever engages one of the notches in the notched disc.

Claim 15

A timer according to claim 13, wherein the detent means comprises a pawl activated by the follower lever and having a lug engaging the projection of the start lever when the start lever is in the operating position.

Claim 16

A timer according to claim 14, further comprising a rotatable shaft, the pointers being mounted on the shaft for rotation therewith; and means for mounting the pawl in such a manner that the pawl pivots in one direction so that the lug of the pawl does not get caught in one of the notches in the notched disc when the notched disc rotates in the opposite direction.

Claim 17

A timer according to claim 1, wherein the transmission gear train includes a first pinion mounted on a shaft of the motor for rotation therewith, a first gear mounted on a displaceable shaft for rotation therewith, a second gear meshing with the first pinion and the first gear in such a manner that the first gear rotates in the same direction as the motor shaft, and a second pinion mounted on the motor shaft for rotation therewith.

Claim 18

A timer according to claim 16, wherein the switch means includes a leaf spring pivotable about one end, the other end engaging the displaceable shaft, and a pivotable switch lever slidably engaging the leaf spring to pivot the other end in such a manner that the displaceable shaft is displaced to disengage the first gear from the second gear and engage the first gear with the second pinion so that the first gear rotates in a direction opposite to that of the motor shaft, whereby the direction of rotation of the pointer may be reversed without reversing the direction of rotation of the motor shaft.

Claim 19

In a timer including a motor having a rotatable shaft; a first pinion mounted on the motor shaft for rotation therewith; a first gear mounted on a displaceable shaft for rotation therewith; a second gear meshing with the first gear and the first pinion in such a manner that the first gear rotates in the same direction as the motor shaft; a second pinion mounted on the motor shaft for rotation therewith; a pointer mounted on a shaft for rotation therewith, the pointer shaft being driven by the first gear through a transmission system and the pointer being settable to a predetermined position representing a desired time interval; a start lever for actuating the motor in such a manner that the pointer rotates toward a zero position from the predetermined position; and a trip mechanism for actuating a stop lever when the pointer has rotated back to the zero position to stop the motor; the improvement comprising: switch means for selectively changing the direction of rotation of the pointer so that the pointer rotates away from the zero position, the switch means including a leaf spring pivotable about one end, the other end engaging the displaceable shaft, and a pivotable switch lever slidably engaging the leaf spring to pivot the other end in such a manner that the displaceable shaft is displaced to disengage the first gear from the second gear and engage the first gear with the second pinion so that the first gear rotates in a direction opposite to that of the motor shaft and slidably engaging the trip mechanism to prevent the actuation of the stop lever by the trip mechanism when the pointer rotates away from the zero position; and means for manually actuating the stop lever so that the motor can be stopped when the pointer rotates away from the zero position, whereby the timer is operable as a stop watch.

Claim 20

In a timer including a motor having a rotatable shaft; a first pinion mounted on the motor shaft for rotation therewith; a first gear mounted on a displaceable shaft for rotation therewith; a second gear meshing with the first gear and the first pinion in such a manner that the first gear rotates in the same direction as the motor shaft; a second pinion mounted on the motor shaft for rotation therewith; a pointer mounted on a shaft for rotation therewith, the pointer shaft being driven by the first gear through a transmission system and the pointer being settable to a predetermined position representing a desired time interval; a start lever for actuating the motor in such a manner that the pointer rotates toward a zero position from the predetermined position; and a trip mechanism for actuating a stop lever when the pointer has rotated back to the zero position to stop the motor; the improvement comprising: switch means for selectively changing the direction of rotation of the pointer so that the pointer rotates away from the zero position, the switch means including a leaf spring pivotable about one end, the other end engaging the displaceable shaft, and a pivotable switch lever slidably engaging the leaf spring to pivot the other end in such a manner that the displaceable shaft is displaced to disengage the first gear from the second gear and engage the first gear with the second pinion so that the first gear rotates in a direction opposite to that of the motor shaft and slidably engaging the trip mechanism to prevent the actuation of the stop lever by the trip mechanism when the pointer rotates away from the zero position; and means for manually actuating the stop lever so that the motor can be stopped when the pointer rotates away from the zero position, whereby the timer is operable as a stop watch.