US3115847A

US3115847A - Aerial tramways

Info

Publication number: US3115847A
Application number: US236326A
Authority: US
Inventors: Robert H Turner; Robert E Kinney
Original assignee: Gen Tech Inc
Current assignee: Gen Tech Inc; General Techniques Inc
Priority date: 1962-11-08
Filing date: 1962-11-08
Publication date: 1963-12-31
Anticipated expiration: 1980-12-31

Description

Dec. 31, 1963 R. H. TURNER ETAL AERIAL TRAMWAYS 2 Sheets-Sheet 1 Filed NOV. 8, 1962 Ll T a YATTO NE Y5 1963 R. H. TURNER ET AL AERIAL TRAMWAYS Filed Nov. 8, 1962 2 Sheets-Sheet 2 ||||II I [III L ATTORNEKS United States Patent 3,115,847 AERIAL TRAMWAYS Robert H. Turner, Levittown, Pat, and Robert E. Kinney, Pennington, N.J., assignors to General Techniques, Inc, West Trenton, N..I., a Corporation of New Jersey Filed Nov. 8, 1962, Ser. No. 236,326 9 Claims. (Cl. 104-178) This invention in general relates to cable type aerial tramways and in particular relates to safety means for stopping the operation of the tramway in the event the cable becomes disengaged from its. supporting means.

As is well understood by those skilled in the art, a typical tramway of the kind in question is represented by the so-called ski-lift. This ordinarily comprises a cable which is disposed, for example, in the form of a loop extending between the top and bottom of the ski slope. The cable is movable in (translation and is supported at various points around the loop by pairs of sheaves suitably mounted on towers. The cable has a plurality of hangers which support seats or draw bars for use in transporting skiers along the slope.

Experience has shown that often times on one or more of the towers the cable becomes disengaged from the sheaves and that this caused serious damage to person and property. The principal reason damage has ensued is that safety devices on tramways have been incapable of functioning to stop cable motion as soon as the cable becomes disengaged. Gable motion, after disengagement, has resulted, for example, in the hanger and seat (with occupant) crashing into a tower or being dragged along the ground. Also damage to equipment results when the cable and hanger are fouled in the tower to a degree to prevent cable motion while at the same time the cable drive mechanism continues to force the cable onwardly.

The principal object of the present invention is toprovide safety means for an aerial tramway which will positively and reliably function to halt cable operation in the event the cable becomes disengaged from its supporting sheaves.

The invention contemplates that the cable be wholly or partly made from magnetic material and that a sensing device having means for developing a magnetic field be closely associated with the sheaves in a manner so that the field threads the cable when the same is properly disposed on the sheaves but does not thread the cable when the same has become disengaged from the sheaves. The device is provided with means which is actuated when the field is threading the cable to condition the cable drive mechanism to move the cable, and which is actuated when the cable is not threaded by the field to condition the drive mechanism to stop cable motion.

The magnetic concept for sensing or detecting the presence or absence of the cable on the sheaves has particularly important advantages in that there is no physical or mechanical connection with the cable which could be rendered inoperative by accumulations of ice, snow, dirt or other foreign objects. This is particularly significant because in safety schemes used heretofore, inability to give satisfactory performance has been due largely to failure of such connections.

In the preferred arrangement the invention contemplates a permanent magnet which is disposed between the sheaves and mounted so as to be movable toward and away from the cable. The magnet is spaced firom the cable so that when the cable is properly running on the sheave, the magnetic attraction pulls the magnet toward the cable to an operative position. The magnet is interconnected with a switch and in the operative position the switch is actuated so as to condition the cable drive mechanism for moving the cable. In the event the cable is removed from the sheaves, the magnetic attraction is broken and the magnet moves away from its operative position and in doing so lactuates the switch so as to condition the cable drive mechanism to stop the cable motion.

The invention will be described below in connection with the following drawings wherein:

FIGURE 1 is an elevational view of the top part of a typical support station having a pair of sheaves carrying a cable with a sensing device disposed between the sheaves just below the cable;

FIGURE 2 is a plan view of FIGURE 1;

FIGURE 3 is a cross section taken along the line 33 of FIGURE 1;

FIGURE 4 is an isometric view of a pair beam showing the manner in which the sensing device is supported thereon;

FIGURE 5 is an enlarged sectional, elevational view taken along the lines 55 of FIGURE 1;

FIGURE 6 is a plan section taken along the lines 6--6 of FIGURE 5;

FIGURE 7 is a cross section taken along the line 77 of FIGURE 5;

FIGURE 8 is a sectional elevational view on a reduced scale of a modified form of a sensing device;

FIGURE 9 is a cross section along the line 99 of FIGURE 8; and

FIGURE 10 is a diagram view of a tramway system.

In FIGURE 1 a typical cable support station for a skilift is illustrated. This includes the tower 1 having the vertically extending post 2 and cross beam 3 connected to the top of the post. On one end of the cross beam 3 is a pair beam 4 (see FIGURE 4) comprising the

side plates

5 and 6 which are rigidly interconnected by the tie piece 10. A pin III is fixed to the bracket 12 on the cross beam 3. The tie piece 10 of the pair beam 4 is rotatably mounted on the pin. The pair beam 4 can move about the pin 11 so that the pin constitutes a pivot for the pair beam.

The shafts :15 and 16 on the pair beam rotatably mount the

sheaves

20 and 21 which mount the carrier cable 22. In the embodiment shown, the cable is adapted to be moved to the left as viewed in FIGURE 1. The cable 22 carries a plurality of hangers, one of which is illustrated by the hanger rod 23 and the hanger grip 24-. The grip 2 4 is adapted to pass over the sheaves in the usual manner. The side plate 5 of the pair beam 4 carries a pair of depending

brackets

25 and 26 which carry the lower guard 30. The guard 30 is adapted to contact the hanger rod 23 so as to maintain the hanger in the correct position as the hanger grip is passing the sheaves.

The sheaves are constructed in the usual form, for example, the sheave 21 has a groove 33 which is configured to carry the cable, the groove terminating on the outside by the ledge 3d and on the inside by the ledge 35. The ledge 34 is of considerably smaller diameter than the ledge 35 so as to accommodate the passage of the hanger grip 24.

The side plate 6 of the pair beam 4 carries an upper guard 36. The upper guard is disposed closely adjacent the interior ledge 35 of the sheave and prevents the cable from coming off the sheave in the event it should ride up over the ledge 35.

As well understood in the art, the structure described above is conventional form and a further description of the same is unnecessary.

For sensing the presence or absence of the cable on the sheave, a small composite sensing device comprising a magnet and switch is mounted on the pair beam just below the cable. In FIGURES '1, 2 and 3, the sensing device is indicated at th. The device 43 is mounted on the pair beam as by a transverse plate 41 secured to the side plates and 6 (see FIGURE 4).

The general structure of the sensing device 40 is shown in FIGURES 5, 6 and 7 and comprises a hollow housing 42 comprising a base 43 and a casing 44 affixed to the base. The casing is made of a non-magnetic material. The base and casing form a closed housing which is sealed in the sense that ice, dirt, etc. is excluded from the interior.

Inside of the housing a pair of uprights 5t"; and 51 support a pin 52 which rotatably mounts the beam 53. One end of the beam 53 carries a permanent magnet 54 and the other end carries an adjustable counterweight 55'. As indicated, the beam 53 is threaded so that the weight can be adjusted to a desired position and locked by the set screw 60.

In between the uprights 5t) and 51 is a switch 61 which is of conventional form and has actuating arm 62 which is spring biased upwardly to engage the beam and exert a force on the beam tending to rotate the same clockwise (as viewed in FIGURE 5). The weight of the magnet 54 also tends to rotate the beam clockwise. The counterweight 55 tends to rotate the beam counterclockwise or in opposition to the arm 62 and magnet 54.

As best shown in FIGURES l and 3, the device 4% is mounted so that the magnet 54 is disposed just below the cable 22. The relative position of the cable and magnet is also indicated in FIGURE 5.

In FIGURE 5 the magnet is shown engaged with the underside of the top of the casing This is the operative position of the magnet. The inoperative position is indicated by the dotted lines 54' (in this position the counterweight 55 engages the underside of the casing 44). Movement of the magnet as between the operative and inoperative positions is provided by the rotation of the beam 53 about the pivot 52..

In either the operative or inoperative positions, the magnet is spaced from the cable (assuming the cable is properly carried by the sheaves) so that the field of the magnet threads the cable and tie magnetic attraction pulls the magnet towards the cable. For example, if the magnet is in the inoperative position 54 it will move upwardly toward the cable to its operative position. The rotational limits of the beam (as defined by the engagement of the magnet and counterweight with the housing) is important in positioning the magnet for desired operation.

When the cable is not disposed on the sheaves properly i.e., so that the field of the magnet no longer threads the cable, there is no longer a magnetic attraction and the weight of the magnet and the force of the arm 62 rotate the beam clockwise and hence move the magnet to its inoperative position.

When the magnet is in the operative position, the actuating arm 62 operates the switch fill to condition the circuits controlling the cable drive mechanism so that the same will move the cable in translation. When the magnet is moved to its inoperative position, the arm 62 is moved to actuate the switch 61 to condition the circuits for the cable drive mechanism so that the same halts the movement of the cable. For a fail safe arrangement, it is preferred that the switch 61 be closed when the magnet is in the up or operative position and open when the magnet is in the down or inoperative position.

In the embodiment shown in FIGURE 5, the weight 60 positioned on the beam counterbalances the weight of the magnet and the force of the arm 62 so that relatively little magnetic force is required to positively move and hold the magnet in its operative position. On the other hand, the counterbalancing position of the weight is such that when the magnetic force is no longer present, the weight will not interfere with the magnet moving downwardly to its inoperative position.

The magnet has a field strength sufiicient to prevent false response. For example, any upward motion of the cable which may result from cable vibration or from the hanger grip passing over a sheave will not cause the magnet to drop away. False indications are also prevented by adjusting the switch so that the arm 62. must move over a substantial distance before the switch is actuated.

In FIGURES 8 and 9 we have shown a modified version of the sensing device which comprises a housing 63 having a base 64, a casing 65 made of non-magnetic material, amagnet 6-5 mounted on a slide means 70 which provides for the magnet to be moved in a vertical direction and a switch 71 which has an operating arm 72 spring biased upwardly to engage the bottom of the magnet. In the position shown in FIGURES 8 and 9, the magnet is resting on a shoulder on the slide means and is in its down or inoperative position, i.e., where there is no cable present to develop the magnetic attraction. In this position the arm '72 is moved to actuate the switch 71 to condition the cable drive mechanism circuits to stop the operation of the drive mechanism. When the cable is properly disposed on the sheaves, the magnet moves upwardly on the slide means 7t) to its operative position or until it engages the casing 65. The arm 72 follows the upward movement of the magnet and actuates the switch, which conditions the control circuits for cable drive mechanism to cause the same to move the cable.

As will be understood by those skilled in the art, several stations of the kind described in FIGURES l and 2 are disposed in the area to be serviced by the tramway and the cable extends between these stations. For example, in FIGURE 10 we have diagrammatically illustrated a tramway which comprises a plurality of cable support stations S together with a cable C which is arranged in the form of a continuous loop and which extends around and is carried by the several stations. The power drive mechanism for moving the cable in translation is in dicated by P. In the embodiments described above conductors C are connected between the various stations S to the switches S thereon and all of the switches are in series with one another and the loop connected to the control circuits in the power station P. This series arrangement of switches is preferred because when the cable is properly carried on the sheaves, the series loop is closed and when any one or more of the cables is improperly operating or is disengaged from its sheaves, the series loop is opened. This makes for a fail safe arrangement which is highly desirable.

With reference to FIGURES 1 and 2, it will be observed that it is virtually impossible for the cable to become disengaged with the sheaves via the large shoulder 35 due to the upper guard 36. Thus, the cable cannot come off the sheave and fall down on the housing 40 of the sensing device. In the event that the cable moves off the sheaves via the lower shoulder, it will be seen that it is impossible for the cable to contact the housing 42 because the end of the housing lies in the same plane as the plane containing the front faces of the sheaves.

As it will be apparent from what has been described, it is virtually impossible for accumulations of ice, snow, etc. to foul the operation of the magnet because the housing is sealed against entry of the same. Also, even if some ice or snow should accumulate on top of the housing, i.e., in the space between the top of the housing and the cable, this will not effect operation because the field strength of the magnet is chosen to that the reluctance change is immaterial.

We claim:

1. In an aerial tram-way having an elongated carrier cable movable in translation together with a plurality of cable support stations and power mechanism for moving the cable in translation, in at least one station, tramway safety means including the combination of support means on the station carrying said cable and providing for movement of the cable in translation, the cable at least in part being comprised of magnetic material;

a permanent magnet;

means mounting said magnet on said station and spacing the magnet from the cable when the cable is carried by said support means at a distance to cause magnetic attraction between the magnet and said magnetic material and the mounting means providing for the magnet to be moved toward the cable by the force of the magnetic attraction to an operative position and the mounting means providing for the magnet to move away from the operative position to an inoperative position when the cable is not carried by the support means and there is no magnetic attraction between the magnet and the magnetic material; switch means mounted on said station; and

connections between said switch means and said magnet providing for actuation of the switch means as between said operative and inoperative positions of the magnet, the switch means being for use in controlling said power mechanism.

2. In an aerial tramway having an elongated carrier cable movable in translation together with a plurality of cable support stations and power mechanism for moving the cable in translation, in at least one station, tramway safety means including the combination of:

support means on the station carrying said cable and providing for movement of the cable in translation, the cable at least in part being comprised of magnetic material;

a closed housing mounted on said station, the housing having a top made of non-magnetic material;

a permanent magnet disposed inside of said housing below said top;

. teans mounting said magnet in the housing for movement toward and away from said top;

mechanism supporting said housing on said station with said top adjacent to the cable, when the cable is carried by said support means and spacing the magnet from the cable at a distance to cause magnetic attraction between the magnet and said magnetic material and the mounting means providing for the magnet to be moved toward the cable by the force of the magnetic attraction to an operative position and the mounting means providing for the magnet to move away from the operative position to an inoperative position when the cable is not carried by the support means and there is no magnetic attraction between the magnet and the magnetic material;

switch means in said housing; and

connections in said housing between said switch means and said magnet providing for actuation of the switch means as between said operative and inoperative positions of the magnet, the switch means being for use in controlling said power mechanism.

3. In an aerial tramway having an elongated carrier cable movable in translation together with a plurality of cable support stations and power mechanism for moving the cable in translation, in at least one station, tramway safety means including the combination of:

an elongated beam in said housing;

means connecting said beam with said housing and including pivot means providing for rotation of the beam about a generally horizontally extending axis, the rotational axis being located interjacent opposite ends of the beam;

weight means connected adjacent one end of said beam and a permanent magnet connected adjacent the other end of said beam;

mechanism supporting said housing on said station with said top adjacent to the cable when the cable is carried by said support means and spacing the magnet from the cable at a distance to cause magnetic attraction between the magnet and said magnetic material, said pivot means providing for the magnet to be rotated in a direction toward said cable by the force of the magnetic attraction to an operative position and the pivot means providing for the magnet to rotate in the opposite direction to an inoperative position when the cable is not carried by the support means and there is no magnetic attraction between the magnet and the magnetic material; switch means in said housing; and

means in said housing interconnecting said switch with said beam to provide for actuation of the switch as between said operative and inoperative positions of the magnet, the switch means being for use in controlling said power mechanism.

4. In an aerial tramway having an elongated carrier cable movable in translation together with a plurality of cable support stations and power mechanism for moving the cable in translation, in at least one station, tramway safety means including the combination of:

support means on the station carrying said cable and providing for movement of the cable in translation,

, the cable at least in part being comprised of magnetic material;

a \t/ertically extending slide in said housing below said a permanent magnet inside of said housing and mount ed on said slide for movement in a vertical direction;

mechanism supporting said housing on said station with said top adjacent to the cable when the cable is carried by said support means and spacing the magnet from the cable at a distance to cause magnetic attraction between the magnet and said magnetic material and said slide providing for the magnet to be moved toward the cable by the force of the magnetic attraction to an operative position and the slide providing for the magnet to move away from the operative position to an inoperative position when the cable is not carried by the support means and there is no magnetic attraction between the magnet and the magnetic material;

switch means in said housing; and

means in said housing interconnecting said switch with said magnet to provide for actuation of the switch as between said operative and inoperative positions of the magnet, the switch means being for use in controlling said power mechanism.

5. In an aerial tramway having an elongated carrier cable movable in translation together with a plurality of cable support stations and power mechanism for moving the cable in translation, in at least one station, tramway safety means including the combination of:

the cable at least in part being comprised of magnetic material;

magnetic means for generating a magnetic field;

mechanism mounting said magnetic means on said station and positioning the magnetic means so that its field threads the cable when the cable is carried by said support means and so that the field does not thread the cable when the cable is not supported by the support means;

switch means mounted on said station, the switch means having an open condition and a closed condition, the switch means being for use in controlling said power mechanism; and

mechanism connected with the switch means and operative when said field is threading said cable to actuate said switch means for the closed condition and when said field is not threading said cable to actuate said means for the open condition.

6. In an aerial tramway having an elongated carrier cable movable in translation together with a plurality of cable support stations and power mechanism for moving the cable in translation, in at least one station, tramway safety means including the combination of:

magnetic means for generating a magnetic field;

mechanism mounting said magnetic means on said station and positioning the magnetic means so that its field threads the cable when the cable is carried by said support means and so that the field does not thread the cable when the cable is not supported by the support means; and

switch means mounted on said station, said magnetic means including mechanism connected with the switch means and operative as between said condition of threading and said condition of non-threading to actuate the switch means, the switch means being for use in controlling said power mechanism.

7. For an aerial tramway having a cable comprised at least in part of magnetic material, a cable sensing de vice comprising:

a hollow, closed housing;

an elongated beam in said housing;

a permanent magnet connected adjacent one end of said beam;

a counterweight connected adjacent the opposite end of said beam;

means connected to the beam interjacent said magnet and counterweight and supporting the beam for rotation about an axis alternatively in opposite directions, the magnet tending to rotate the beam about said axis in one direction and the counterweight tending to rotate the beam about said axis in the opposite direction;

means on said housing to define the limits of rotation of the beam in said directions; and

switch means in said housing and having an arm en gaged with said beam and movable with the beam to provide for actuation of the switch as between said rotational limits. 8. For an aerial tramway having a cable comprised at least in part of magnetic material, a cable sensing device comprising:

a hollow, closed housing; a permanent magnet in said housing; slide means in said housing mounting said magnet for movement in a vertical direction from an inoperative position defined by the engagement of the magnet and the slide to an operative position defined by the engagement of the magnet and the housing; and

switch means in said housing having an arm engaged with said magnet and movable with the magnet to provide for actuation of the switch as between said operative and inoperative positions.

9. For an aerial tramway having a cable comprised at least in part of magnetic material, a cable sensing device comprising:

a hollow, closed housing;

a permanent magnet in said housing;

means mounting the magnet in the housing for movement as between two positions;

means on said housing controlling the limits of magnet movement to define each said position; and

switch means in said housing having an arm operatively connected with said magnet to provide for actuation of the switch as between said two positions of the magnet.

References Cited in the file of this patent UNITED STATES PATENTS 1,294,813 Lammert et al Feb. 18, 1919 2,057,173 Waalkes Oct. 13, 1936 3,071,083 Hochrnuth Ian. 1, 1963 FOREIGN PATENTS 1,070,763 France Feb. 24, 1954

Claims

1. IN AN AERIAL TRAMWAY HAVING AN ELONGATED CARRIER CABLE MOVABLE IN TRANSLATION TOGETHER WITH A PLURALITY OF CABLE SUPPORT STATIONS AND POWER MECHANISM FOR MOVING THE CABLE IN TRANSLATION, IN AT LEAST ONE STATION, TRAMWAY SAFETY MEANS INCLUDING THE COMBINATION OF: SUPPORT MEANS ON THE STATION CARRYING SAID CABLE AND PROVIDING FOR MOVEMENT OF THE CABLE IN TRANSLATION, THE CABLE AT LEAST IN PART BEING COMPRISED OF MAGNETIC MATERIAL; A PERMANENT MAGNET; MEANS MOUNTING SAID MAGNET ON SAID STATION AND SPACING THE MAGNET FROM THE CABLE WHEN THE CABLE IS CARRIED BY SAID SUPPORT MEANS AT A DISTANCE TO CAUSE MAGNETIC ATTRACTION BETWEEN THE MAGNET AND SAID MAGNETIC MATERIAL AND THE MOUNTING MEANS PROVIDING FOR THE MAGNET TO BE MOVED TOWARD THE CABLE BY THE FORCE OF THE MAGNETIC ATTRACTION TO AN OPERATIVE POSITION AND THE MOUNTING MEANS PROVIDING FOR THE MAGNET TO MOVE AWAY FROM THE OPERATIVE POSITION TO AN INOPERATIVE POSITION WHEN THE CABLE IS NOT CARRIED BY THE SUPPORT MEANS AND THERE IS NO MAGNETIC ATTRACTION BETWEEN THE MAGNET AND THE MAGNETIC MATERIAL; SWITCH MEANS MOUNTED ON SAID STATION; AND CONNECTIONS BETWEEN SAID SWITCH MEANS AND SAID MAGNET PROVIDING FOR ACTUATION OF THE SWITCH MEANS AS BETWEEN SAID OPERATIVE AND INOPERATIVE POSITIONS OF THE MAGNET, THE SWITCH MEANS BEING FOR USE IN CONTROLLING SAID POWER MECHANISM.