Pit-type dock leveler

Claim 2

A dock leveler for installation in a dock having a pit formed therein, comprising: a frame, having a front portion, an upper rear portion and a lower rear portion; a ramp member, having a top side, and a bottom side, a front edge and a rear edge, pivotally secured along the rear edge thereof to the upper rear portion of said frame for pivoting movement thereon about a horizontal axis; means carried by said frame for upwardly biasing said ramp member relative to said frame; a lip member, having a top side, a bottom side, a front edge and a rear edge, the rear edge thereof being pivotally secured to the front edge of said ramp member whereby the lip member pivots between an extended cantilever position, lying substantially in the plane of said ramp member, and a downwardly folded position, lying in a plane substantially normal to the plane of said ramp member; lip extending member means, having a first end and a second end and pivotally secured at the medial portion thereof to the bottom side of said ramp member adjacent the front edge thereof, the first end of said lip extending member means being in operative contact with the bottom side of said lip member for rotating said lip member upwardly about its pivot point To an extended cantilever position when the first end of said lip extending member means is upwardly rotated about its pivotal securement to said ramp member; means, responsive to the upward pivoting movement of said ramp member, for pivoting said lip extending member means, said means interconnecting the first end of said lip extending member means and the front portion of said frame; a rigid one-piece detent formed on the bottom side of said lip member adjacent the rear edge thereof; a latch member pivotally secured at its medial portion to the bottom side of said ramp member and having a hand grip formed on the first end portion thereof and a detent-engaging surface formed on the second end thereof, the mass of said latch member between the medial portion and the first end portion being greater than the mass between the medial portion and the second end whereby gravity acting on said latch member urges the first end portion thereof downwardly thereby biasing the detentengaging surface thereof into abutment with said detent whereby said lip member is releasably retained in a fully extended cantilever position; and pedestal means carried by the front portion of said frame for contacting the first end of said latch member when said ramp member reaches its lowest position thereby urging the first end of said latch member upwardly against the urging of gravity and releasing said lip member from its fully extended cantilever position.

Claim 3

A dock leveler as defined in claim 1 wherein said means for pivoting said lip extending member means is a flexible cable.

Claim 4

A dock leveler as defined in claim 1 wherein said biasing means is provided by gravity acting on the first end portion of said latch member and urging it downwardly.

Claim 5

A dock leveler for installation in a dock having a pit formed therein, comprising: a frame, having a front portion, an upper rear portion and a lower rear portion; a ramp member, having a top side, and a bottom side, a front edge and a rear edge, pivotally secured along the rear edge thereof to the upper rear portion of said frame for pivoting movement thereon about a horizontal axis; means carried by said frame for upwardly biasing said ramp member relative to said frame; a lip member, having a top side, a bottom side, a front edge and a rear edge, the rear edge thereof being pivotally secured to the front edge of said ramp member whereby the lip member pivots between an extended cantilever position, lying substantially in the plane of said ramp member, and a downwardly folded position, lying in a plane substantially normal to the plane of said ramp member; lip extending member means, having a first end and a second end and pivotally secured at the medial portion thereof to the bottom side of said ramp member adjacent the front edge thereof, the first end of said lip extending member means being in operative contact with the bottom side of said lip member for rotating said lip member upwardly about its pivot point to an extended cantilever position when the first end of said lip extending member means is upwardly rotated about its pivotal securement to said ramp member; means, responsive to the upward pivoting movement of said ramp member, for pivoting said lip extending member means, said means interconnecting the second end of said lip extending member means and the front portion of said frame; a detent formed on the bottom side of said lip member adjacent the rear edge thereof; a latch member pivotally secured at its medial portion to the bottom side of said ramp member and having a hand grip formed on the first end portion thereof and a detent-engaging surface formed on the second end thereof, the mass of said latch member between the medial portion and the first end portion being greater than the mass between the medial portion and the second end whereby gravity acting on said latch member urges the first end portion thereof downwardly thereby biasing the detenT-engaging surface thereof into abutment with said detent whereby said lip member is releasably retained in a fully extended cantilever position; pedestal means carried by the front portion of said frame for contacting the first end of said latch member when said ramp member reaches its lowest position thereby urging the first end of said latch member upwardly against the urging of gravity and releasing said lip member from its fully extended cantilever position; ramp elevating roller means journaled on the front portion of said frame and extending upwardly therefrom for elevating said ramp; ramp elevating member means, having a first end, a second end and a medial portion, pivotally secured at the first end thereof to the bottom side of said ramp member and having a convex cam surface formed on the lower edge thereof for bearing on said ramp elevating roller means; and elongated rigid link means, having a first end and a second end, pivotally secured at the first end thereof to the bottom side of said lip member and pivotally secured at the second end thereof to the medial portion of said ramp elevating member means, for transmitting the downward movement of said lip member therethrough to said ramp elevating member means thereby causing the convex cam surface of said ramp elevating member means to move rollingly over said ramp elevating roller means thereby raising said ramp member to dock level from a position therebelow.

Claim 6

A dock leveler for installation in a dock having a pit formed therein, comprising: a frame, having a front portion, an upper rear portion and a lower rear portion; a ramp member, having a top side, and a bottom side, a front edge and a rear edge, pivotally secured along the rear edge thereof to the upper rear portion of said frame for pivoting movement thereon about a horizontal axis; means carried by said frame for upwardly biasing said ramp member relative to said frame; a lip member, having a top side, a bottom side, a front edge and a rear edge, the rear edge thereof being pivotally secured to the front edge of said ramp member whereby the lip member pivots between an extended cantilever position, lying substantially in the plane of said ramp member, and a downwardly folded position, lying in a plane substantially normal to the plane of said ramp member; lip extending member means, having a first end and a second end and pivotally secured at the medial portion thereof to the bottom side of said ramp member adjacent the front edge thereof, the first end of said lip extending member means being in operative contact with the bottom side of said lip member for rotating said lip member upwardly about its pivot point to an extended cantilever position when the first end of said lip extending member means is upwardly rotated about its pivotal securement to said ramp member; means, responsive to the upward pivoting movement of said ramp member, for pivoting said lip extending member means, said means interconnecting the second end of said lip extending member means and the front portion of said frame; a detent formed on the bottom side of said lip member adjacent the rear edge thereof; a latch member pivotally secured at its medial portion to the bottom side of said ramp member and having a hand grip formed on the first end portion thereof and a detent-engaging surface formed on the second end thereof, the mass of said latch member between the medial portion and the first end portion being greater than the mass between the medial portion and the second end whereby gravity acting on said latch member urges the first end portion thereof downwardly thereby biasing the detenT-engaging surface thereof into abutment with said detent whereby said lip member is releasably retained in a fully extended cantilever position; pedestal means carried by the front portion of said frame for contacting the first end of said latch member when said ramp member reaches its lowest position thereby urging the first end of said latch member upwardly against the urging of gravity and releasing said lip member from its fully extended cantilever position; ramp elevating roller means journaled on the front portion of said frame and extending upwardly therefrom for elevating said ramp; ramp elevating member means, having a first end, a second end and a medial portion, pivotally secured at the first end thereof to the bottom side of said ramp member and having a convex cam surface formed on the lower edge thereof for bearing on said ramp elevating roller means; and elongated rigid link means, having a first end and a second end, pivotally secured at the first end thereof to the bottom side of said lip member and pivotally secured at the second end thereof to the medial portion of said ramp elevating member means, for transmitting the downward movement of said lip member therethrough to said ramp elevating member means thereby causing the convex cam surface of said ramp elevating member means to move rollingly over said ramp elevating roller means thereby raising said ramp member to dock level from a position therebelow.

Claim 7

A dock leveler as defined in claim 4 characterized further to include: at least one bracket means formed on the front portion of said frame and extending outwardly and upwardly therefrom for supporting the front edge of said lip member when the lip member is in the downwardly folded position thereby rigidly supporting said ramp member at dock level in a horizontal cross-traffic position.

Claim 8

A dock leveler as defined in claim 5 wherein the passage of the second end of said ramp elevating member means over said ramp elevating roller means raises said ramp member slightly above the dock level thereby allowing the front edge of said lip member to rise above and seat in said bracket means.

Claim 9

A dock leveler as defined in claim 1 wherein said means for upwardly biasing said ramp member is characterized further to include: first compression spring means operatively connected at one end thereof to said frame and operatively connected at the opposite end thereof to the bottom side of said ramp member for biasing said ramp member upwardly relative to said frame; and adjusting means operatively disposed intermediate the opposite end of said first compression spring means and said ramp member for adjusting the preloading of said first compression spring means and thereby adjusting the magnitude of upward biasing of said ramp member relative to said frame.

Claim 10

A dock leveler as defined in claim 7 wherein said means for upwardly biasing said ramp member is characterized further to include: second compression spring means coaxially aligned with and carried within said first compression spring means for providing biasing supplemental to said first compression spring means; and preloading means for adjustably preloading said second compression spring means thereby adjusting the magnitude of bias provided by said second compression spring means supplemental to said first compression spring means to counterbalance said ramp member.

Claim 11

A dock leveler as defined in claim 8 wherein said first compression spring means is operatively connected at the one end thereof to the lower rear portion of said frame and is oriented in a generally vertical position.

Claim 12

A dock leveler as defined in claim 9 wherein said first and second compression spring means are adjusted by said adjusting means and preloading means, respectively, to counterbalance said ramp member when said ramp member is pivoted to a position slightly above the horizontal.

Claim 13

In combination with a dock leveler for installation on a dock hAving a pit formed therein of the type which comprises a frame, having a front portion, an upper rear portion, and a lower rear portion; a ramp member, having a top side, a bottom side, a front edge and a rear edge, pivotally secured along the rear edge thereof to the upper rear portion of said frame for pivoting movement thereon about a horizontal axis; means carried by said frame for upwardly biasing said ramp member relative to said frame; and a lip member, having a top side, a bottom side, a front edge and a rear edge, the rear edge thereof being pivotally secured to the front edge of said ramp member whereby the lip member pivots between an extended cantilever position, substantially lying in the plane of said ramp member, and a downwardly folded position, lying in a plane substantially normal to the plane of said ramp member, the improvement comprising: lip extending member means, having a first end and a second end and pivotally secured at the medial portion thereof to the bottom side of said ramp member adjacent the front edge thereof, the first end of said lip extending member means being in operative contact with the bottom side of said lip member for rotating said lip member upwardly about its pivot point to an extended cantilever position when the first end of said lip extending member means is upwardly rotated about its pivotal securement to said ramp member; means, responsive to the upward pivoting movement of said ramp member, for pivoting said lip extending member means, said means interconnecting the second end of said lip extending member means and the front portion of said frame; a rigid one-piece detent formed on the bottom side of said lip member adjacent the rear edge thereof; a latch member pivotally secured at its medial portion to the bottom side of said ramp member and having a hand grip formed on the first end portion thereof and a detent-engaging surface formed on the second end thereof, the mass of said latch member between the medial portion and the first end portion being greater than the mass between the medial portion and the second end whereby gravity acting on said latch member urges the first end portion thereof downwardly thereby biasing the detent-engaging surface thereof into abutment with said detent whereby said lip member is releasably retained in a fully extended cantilever position; and pedestal means carried by the front portion of said frame for contacting the first end of said latch member when said ramp member reaches its lowest position thereby urging the first end of said latch member upwardly against the urging of gravity and releasing said lip member from its fully extended cantilever position.

Claim 14

In combination with a dock leveler for installation on a dock hAving a pit formed therein of the type which comprises a frame, having a front portion, an upper rear portion, and a lower rear portion; a ramp member, having a top side, a bottom side, a front edge and a rear edge, pivotally secured along the rear edge thereof to the upper rear portion of said frame for pivoting movement thereon about a horizontal axis; means carried by said frame for upwardly biasing said ramp member relative to said frame; and a lip member, having a top side, a bottom side, a front edge and a rear edge, the rear edge thereof being pivotally secured to the front edge of said ramp member whereby the lip member pivots between an extended cantilever position, substantially lying in the plane of said ramp member, and a downwardly folded position, lying in a plane substantially normal to the plane of said ramp member, the improvement comprising: lip extending member means, having a first end and a second end and pivotally secured at the medial portion thereof to the bottom side of said ramp member adjacent the front edge thereof, the first end of said lip extending member means being in operative contact with the bottom side of said lip member for rotating said lip member upwardly about its pivot point to an extended cantilever position when the first end of said lip extending member means is upwardly rotated about its pivotal securement to said ramp member; means, responsive to the upward pivoting movement of said ramp member, for pivoting said lip extending member means, said means interconnecting the second end of said lip extending member means and the front portion of said frame; a rigid one-piece detent formed on the bottom side of said lip member adjacent the rear edge thereof; a latch member pivotally secured at its medial portion to the bottom side of said ramp member and having a hand grip formed on the first end portion thereof and a detent-engaging surface formed on the second end thereof, the mass of said latch member between the medial portion and the first end portion being greater than the mass between the medial portion and the second end whereby gravity acting on said latch member urges the first end portion thereof downwardly thereby biasing the detent-engaging surface thereof into abutment with said detent whereby said lip member is releasably retained in a fully extended cantilever position; and pedestal means carried by the front portion of said frame for contacting the first end of said latch member when said ramp member reaches its lowest position thereby urging the first end of said latch member upwardly against the urging of gravity and releasing said lip member from its fully extended cantilever position.

Claim 15

In combination with a dock leveler for installation in a dock having a pit formed therein of the type which comprises a frame, having a front portion, an upper rear portion, and a lower rear portion; a ramp member, having a top side, a bottom side, a front edge and a rear edge, pivotally secured along the rear edge thereof to the upper rear portion of said frame for pivoting movement thereon about a horizontal axis; means carried by said frame for upwardly biasing said ramp member relative to said frame; and a lip member, having a top side, a bottom side, a front edge and a rear edge, the rear edge thereof being pivotally secured to the front edge of said ramp member whereby the lip member pivots between an extended cantilever position, substantially lying in the plane of said ramp member, and a downwardly folded position, lying in a plane substantially normal to the plane of said ramp member, the improvement comprising: lip extending member means, having a first end and a second end and pivotally secured at thhe medial portion thereof to the bottom side of said ramp member adjacent the front edge thereof, the first end of said lip extending member means being in operative contact with the bottom side of said lip member for rotating said lip member upwardly about its pivot point to an extended canTilever position when the first end of said lip extending member means is upwardly rotated about its pivotal securement to said ramp member; means, responsive to the upward pivoting movement of said ramp member, for pivoting said lip extending member means, said means interconnecting the second end of said lip extending member means and the front portion of said frame; a detent formed on the bottom side of said lip member adjacent the rear edge thereof; a latch member pivotally secured at its medial portion to the bottom side of said ramp member and having a hand grip formed on the first end portion thereof and a detent-engaging surface formed on the second end thereof, the mass of said latch member between the medial portion and the first end portion being greater than the mass between the medial portion and the second end whereby gravity acting on said latch member urges the first end portion thereof downwardly thereby biasing the detent-engaging surface thereof into abutment with said detent whereby said lip member is releasably retained in a fully extended cantilever position; pedestal means carried by the front portion of said frame for contacting the first end of said latch member when said ramp member reaches its lowest position thereby urging the first end of said latch member upwardly against the urging of gravity and releasing said lip member from its fully extended cantilever position; ramp elevating roller means journaled on the front portion of said frame and extending upwardly therefrom for elevating said ramp member; ramp elevating member means, having a first end, a second end and a medial portion, pivotally secured at the first end thereof to the bottom side of said ramp member and having a convex cam surface formed on the lower edge thereof for engaging said ramp elevating roller means; and elongated rigid link means, having a first end and a second end, pivotally secured at the first end thereof to the bottom side of said lip member and pivotally secured at the second end thereof to the medial portion of said ramp elevating member means, for transmitting downward movement of said lip member therethrough to said ramp elevating member means thereby causing the convex cam surface of said ramp elevating member means to move rollingly over said ramp elevating roller means thereby raising said ramp member to dock level from a position therebelow.

Claim 16

In combination with a dock leveler for installation in a dock having a pit formed therein of the type which comprises a frame, having a front portion, an upper rear portion, and a lower rear portion; a ramp member, having a top side, a bottom side, a front edge and a rear edge, pivotally secured along the rear edge thereof to the upper rear portion of said frame for pivoting movement thereon about a horizontal axis; means carried by said frame for upwardly biasing said ramp member relative to said frame; and a lip member, having a top side, a bottom side, a front edge and a rear edge, the rear edge thereof being pivotally secured to the front edge of said ramp member whereby the lip member pivots between an extended cantilever position, substantially lying in the plane of said ramp member, and a downwardly folded position, lying in a plane substantially normal to the plane of said ramp member, the improvement comprising: lip extending member means, having a first end and a second end and pivotally secured at thhe medial portion thereof to the bottom side of said ramp member adjacent the front edge thereof, the first end of said lip extending member means being in operative contact with the bottom side of said lip member for rotating said lip member upwardly about its pivot point to an extended canTilever position when the first end of said lip extending member means is upwardly rotated about its pivotal securement to said ramp member; means, responsive to the upward pivoting movement of said ramp member, for pivoting said lip extending member means, said means interconnecting the second end of said lip extending member means and the front portion of said frame; a detent formed on the bottom side of said lip member adjacent the rear edge thereof; a latch member pivotally secured at its medial portion to the bottom side of said ramp member and having a hand grip formed on the first end portion thereof and a detent-engaging surface formed on the second end thereof, the mass of said latch member between the medial portion and the first end portion being greater than the mass between the medial portion and the second end whereby gravity acting on said latch member urges the first end portion thereof downwardly thereby biasing the detent-engaging surface thereof into abutment with said detent whereby said lip member is releasably retained in a fully extended cantilever position; pedestal means carried by the front portion of said frame for contacting the first end of said latch member when said ramp member reaches its lowest position thereby urging the first end of said latch member upwardly against the urging of gravity and releasing said lip member from its fully extended cantilever position; ramp elevating roller means journaled on the front portion of said frame and extending upwardly therefrom for elevating said ramp member; ramp elevating member means, having a first end, a second end and a medial portion, pivotally secured at the first end thereof to the bottom side of said ramp member and having a convex cam surface formed on the lower edge thereof for engaging said ramp elevating roller means; and elongated rigid link means, having a first end and a second end, pivotally secured at the first end thereof to the bottom side of said lip member and pivotally secured at the second end thereof to the medial portion of said ramp elevating member means, for transmitting downward movement of said lip member therethrough to said ramp elevating member means thereby causing the convex cam surface of said ramp elevating member means to move rollingly over said ramp elevating roller means thereby raising said ramp member to dock level from a position therebelow.

Claim 17

A dock leveler as defined in claim 12 characterized further to include: at least one bracket means formed on the front portion of said frame and extending outwardly and upwardly therefrom for supporting the front edge of said lip member when the lip member is in the downwardly folded position, thereby rigidly supporting said ramp member at dock level in a horizontal cross-traffic position.

Claim 18

A dock leveler as defined in claim 13 wherein the passage of the second end of said ramp elevating member means over said ramp elevating roller means raises said ramp member slightly above the dock level thereby allowing the front edge of said lip member to rise above and seat in said bracket means.

Claim 19

A dock leveler for installation in a dock having a pit formed therein, comprising: a frame, having a front portion, an upper rear portion and a lower rear portion; a ramp member, having a top side, a bottom side, a front edge and a rear edge, pivotally secured along the rear edge thereof to the upper rear portion of said frame for pivoting movement thereon about a horizontal axis; a lip member, having a top side, a bottom side, a front edge and a rear edge, the rear edge thereof being pivotally secured to the front edge of said ramp member, whereby the lip member pivots between an extended cantilever position, lying substantially in the plane of said ramp member, and a downwardly folded position lying in a plane substantially normal to the plane of said ramp member; first compression spring means operatively connected at one end thereof to said frame And operatively connected at the opposite end thereof to the bottom side of said ramp member for providing upward biasing of said ramp member relative to said frame; second compression spring means coaxially aligned with and carried within said first compression spring means for providing biasing supplemental to said first compression spring means; adjusting means operatively disposed intermediate the opposite end of said first compression spring means and said ramp member for adjusting the preloading of said first compression spring means and thereby adjusting the magnitude of upward biasing of said ramp member relative to said frame; and preloading means operatively engaging said second compression spring means for adjustably preloading said second compression spring means thereby adjusting the magnitude of biasing provided lower said second compression spring means supplemental to said first compression spring means to counterbalance said ramp member.

Claim 20

A dock leveler for installation in a dock having a pit formed therein, comprising: a frame, having a front portion, an upper rear portion and a lower rear portion; a ramp member, having a top side, a bottom side, a front edge and a rear edge, pivotally secured along the rear edge thereof to the upper rear portion of said frame for pivoting movement thereon about a horizontal axis; a lip member, having a top side, a bottom side, a front edge and a rear edge, the rear edge thereof being pivotally secured to the front edge of said ramp member, whereby the lip member pivots between an extended cantilever position, lying substantially in the plane of said ramp member, and a downwardly folded position lying in a plane substantially normal to the plane of said ramp member; first compression spring means operatively connected at one end thereof to said frame And operatively connected at the opposite end thereof to the bottom side of said ramp member for providing upward biasing of said ramp member relative to said frame; second compression spring means coaxially aligned with and carried within said first compression spring means for providing biasing supplemental to said first compression spring means; adjusting means operatively disposed intermediate the opposite end of said first compression spring means and said ramp member for adjusting the preloading of said first compression spring means and thereby adjusting the magnitude of upward biasing of said ramp member relative to said frame; and preloading means operatively engaging said second compression spring means for adjustably preloading said second compression spring means thereby adjusting the magnitude of biasing provided lower said second compression spring means supplemental to said first compression spring means to counterbalance said ramp member.

Claim 21

A dock leveler as defined in claim 15 wherein said first compression spring means is operatively connected at one end thereof to the lower rear portion of said frame and is oriented in a generally vertical position.

Claim 22

A dock leveler as defined in claim 15 characterized further to include: lip extending member means, having a first end and a second end and pivotally secured at its medial portion to the bottom side of said ramp member adjacent the front edge thereof, the first end of said lip extending member means being in operative contact with the bottom side of said lip member for rotating said lip member upwardly about its pivot point to an extended cantilever position when the first end of said lip member means is upwardly rotated about its pivotal securement to said ramp member; and means responsive to the upward pivoting movement of said ramp member for pivoting said lip extending member means, said means interconnecting the second end of said lip extending member means and the front portion of said frame.

Claim 23

A dock leveler as defined in claim 17 characterized further to include: a detent formed on the bottom side of said lip member adjacent the rear edge thereof; a latch member pivotally secured at its medial portion to the bottom side of said ramp member and having a hand grip formed on the first end portion thereof and a detent-engaging surface formed on the second end thereof for engaging said detent to releasably retain said lip member in a fully extended cantilever position.

Claim 24

A dock leveler for installation in a dock having a pit formed therein, comprising: a frame, having a front portion, an upper rear portion and a lower rear portion; a ramp member, having a top side, a bottom side, a front edge and a rear edge, pivotally secured along the rear edge thereof to the upper rear portion of said frame for pivoting movement thereon about a horizontal axis; a lip member, having a top side, a bottom side, a front edge and a rear edge, the rear edge thereof being pivotally secured to the front edge of said ramp member, whereby the lip member pivots between an extended cantilever position, lying substantially in the plane of said ramp member, and a downwardly folded position lying in a plane substantially normal to the plane of said ramp member; first compression spring means operatively connected at one end thereof to said frame and operatively connected at the opposite end thereof to the bottom side of said ramp member for providing upward biasing of said ramp member relative to said frame; second compression spring means coaxially aligned with and carried within said first compression spring means for providing biasing supplemental to said first compression spring means; lip extending member means, having a first end and a second end and pivotally secured at its medial portion to the bottom side of said ramp member adjacent the front edge thereof, the first end of said lip extending member means being in operative contact witH the bottom side of said lip member for rotating said lip member upwardly about its pivot point to an extended cantilever position when the first end of said lip extending member means is upwardly rotated about its pivotal securement to said ramp member; means responsive to the upward pivoting movement of said ramp member for pivoting said lip extending member means, said means interconnecting the second end of said lip extending member means and the front portion of said frame; a detent formed on the bottom side of said lip member adjacent the rear edge thereof; a latch member pivotally secured at its medial portion to the bottom side of said ramp member and having a hand grip formed on the first end portion thereof and a detent-engaging surface formed on the second end thereof, the mass of said latch member between the medial portion and the first end portion being greater than the mass between the medial portion and the second end whereby gravity acting on said latch member urges the first end portion thereof downwardly thereby biasing the detent-engaging surface thereof into abutment with said detent whereby said lip member is releasably retained in a fully extended cantilever position; pedestal means carried by the front portion of said frame for contacting the first end of said latch member when said ramp member reaches its lowest position thereby urging the first end of said latch member upwardly against the urging of gravity and releasing said lip member from its fully extended cantilever position; ramp elevating roller means journaled on the front portion of said frame and extending upwardly therefrom for elevating said ramp; ramp elevating member means, having a first end, a second end and a medial portion, pivotally secured at the first end thereof to the bottom side of said ramp member and having a convex cam surface formed on the lower edge thereof for engaging said ramp elevating roller means; and elongated rigid link means, having a first end and a second end, pivotally secured at the first end thereof to the bottom side of said lip member and pivotally secured at the second end thereof to the medial portion of said ramp elevating member means, for transmitting downward movement of said lip member therethrough to said ramp elevating member means causing the convex cam surface of said ramp elevating member means to move rollingly over said ramp elevating roller means thereby raising said ramp member to dock level from a position therebelow.

Claim 25

A dock leveler for installation in a dock having a pit formed therein, comprising: a frame, having a front portion, an upper rear portion and a lower rear portion; a ramp member, having a top side, a bottom side, a front edge and a rear edge, pivotally secured along the rear edge thereof to the upper rear portion of said frame for pivoting movement thereon about a horizontal axis; a lip member, having a top side, a bottom side, a front edge and a rear edge, the rear edge thereof being pivotally secured to the front edge of said ramp member, whereby the lip member pivots between an extended cantilever position, lying substantially in the plane of said ramp member, and a downwardly folded position lying in a plane substantially normal to the plane of said ramp member; first compression spring means operatively connected at one end thereof to said frame and operatively connected at the opposite end thereof to the bottom side of said ramp member for providing upward biasing of said ramp member relative to said frame; second compression spring means coaxially aligned with and carried within said first compression spring means for providing biasing supplemental to said first compression spring means; lip extending member means, having a first end and a second end and pivotally secured at its medial portion to the bottom side of said ramp member adjacent the front edge thereof, the first end of said lip extending member means being in operative contact witH the bottom side of said lip member for rotating said lip member upwardly about its pivot point to an extended cantilever position when the first end of said lip extending member means is upwardly rotated about its pivotal securement to said ramp member; means responsive to the upward pivoting movement of said ramp member for pivoting said lip extending member means, said means interconnecting the second end of said lip extending member means and the front portion of said frame; a detent formed on the bottom side of said lip member adjacent the rear edge thereof; a latch member pivotally secured at its medial portion to the bottom side of said ramp member and having a hand grip formed on the first end portion thereof and a detent-engaging surface formed on the second end thereof, the mass of said latch member between the medial portion and the first end portion being greater than the mass between the medial portion and the second end whereby gravity acting on said latch member urges the first end portion thereof downwardly thereby biasing the detent-engaging surface thereof into abutment with said detent whereby said lip member is releasably retained in a fully extended cantilever position; pedestal means carried by the front portion of said frame for contacting the first end of said latch member when said ramp member reaches its lowest position thereby urging the first end of said latch member upwardly against the urging of gravity and releasing said lip member from its fully extended cantilever position; ramp elevating roller means journaled on the front portion of said frame and extending upwardly therefrom for elevating said ramp; ramp elevating member means, having a first end, a second end and a medial portion, pivotally secured at the first end thereof to the bottom side of said ramp member and having a convex cam surface formed on the lower edge thereof for engaging said ramp elevating roller means; and elongated rigid link means, having a first end and a second end, pivotally secured at the first end thereof to the bottom side of said lip member and pivotally secured at the second end thereof to the medial portion of said ramp elevating member means, for transmitting downward movement of said lip member therethrough to said ramp elevating member means causing the convex cam surface of said ramp elevating member means to move rollingly over said ramp elevating roller means thereby raising said ramp member to dock level from a position therebelow.

Claim 26

A dock leveler as defined in claim 19 characterized further to include: at least one bracket means formed on the front portion of said frame and extending outwardly and upwardly therefrom for supporting the front edge of said lip member when said lip member is in the downwardly folded position, thereby rigidly supporting said ramp member at dock level in a horizontal cross-traffic position.

Claim 27

A dock leveler as defined in claim 20 wherein the passage of the second end of said ramp elevating member means over said ramp elevating roller means raises said ramp member slightly above the dock level thereby allowing the front edge of said lip member to rise above and seat in said bracket means.