Scissors jack

• US 4,055,329 A
• Filed: 07/19/1976
• Issued: 10/25/1977
• Est. Priority Date: 07/19/1976
• Status: Expired due to Term

• Current Assignee: Dometic Corporation The 2320 Industrial Parkway Elkhart
• Original Assignee: Leisure Manufacturing Inc. (Jacuzzi Brands Corporation)
• Inventors: Hammond, Grover M.
• Primary Examiner(s): Watson, Robert C.
• Application Number:
  US05/706,787
• Time in Patent Office: 463 Days
• Field of Search: 254/86 R, 254/122, 254/126
• US Class Current: 254/424
• CPC Class Codes: B66F 3/12 comprising toggle levers lazy-tongs mechanisms B66F3/22

Abstract

A scissors jack is adapted to be mounted permanently to the bottom frame of a vehicle and enclose the working members of the jack in the closed position. Generally, four of these scissors jacks will be mounted on the four opposite corners of the vehicle to level and stabilize the vehicle when the jacks are extended to their open position. The scissors jack has two opposed pairs of channel-shaped scissors arms. Each pair of arms is pivotally secured at a first end of the arms with the second ends having teeth formed therein. The upper arms of each pair are hingedly connected to a mounting member with their teeth intermeshed and the lower arms of each pair are hingedly connected to a baseplate with their teeth intermeshed. The second ends are mounted in the baseplate and mounting plate by rivets and each pair of rivets has a strap secured on the inside thereof to keep the teeth engaged and to relieve the stress on the rivets. A threaded rod is engaged through an internally threaded nut mounted at one pivot point of the scissors arms, a bushing is mounted at the second pivot point enabling the rod to be rotated to raise and lower the jack by opening and closing the scissors arms. The channel-shaped scissors arms are of a width and depth sufficient substantially to enclose the threaded rod when the jack is in the closed position to protect the threaded rod from debris thrown up during motion of the vehicle. The mounting member is a T-shaped member having channel-shaped arms to stabilize the jack. The T-shaped member and the baseplate have slots aligned with the teeth to allow the teeth to extend therethrough in the fully open position.

Claims

1. A scissors jack comprising:

a baseplate including a first channel-shaped member secured to said plate with the channel thereof opening upwardly of said plate;

means adapted to be mounted permanently to the bottom of a vehicle including a second channel-shaped member aligned substantially parallel with said first channel-shaped member and having its channel opening downwardly towards the baseplate, said mounting means including

a third and a fourth channel-shaped member having their channels opening downwardly, secured to opposite sides of said second channel-shaped member and aligned with one another substantially normal to said second channel-shaped member;

opposed pairs of channel-shaped scissors arms vertically aligned with said channel-shaped members and each pair of said arms being hingedly secured together at one end thereof to form a pivot point, the ends of each pair opposite its pivot point having teeth formed therein, the teeth of the upper arms being intermeshed and the upper arms being hingedly connected to said second channel-shaped member, and having their channels opening downwardly, the teeth of the lower arms being intermeshed and the lower arms being hingedly connected to said first channel-shaped member and having their channels opening upwardly, the toothed ends of the upper arms being disposed for pivotal movement within the channel of the second channel-shaped member and the toothed ends of the lower arms being disposed for pivotal movement within the channel of the first channel-shaped member;

a bushing mounted for limited swinging movement at one pivot point and a nut mounted for limited swinging movement at the other pivot point;

a threaded rod extending between the pivot points and journaled in the bushing for free rotation therein while threadedly engaging in the nut;

means for rotating the rod;

means for preventing axial movement of the rod relative to the bushing, the length of the rod being greater than the distance between pivot points when the scissors arms are closed to their maximum extent;

means for protecting said threaded rod when said scissors arms are closed to their maximum extent;

rotation of the rod serving to open or close the scissors arms whereby to vary the vertical spacing between the first and second channel-shaped members without changing the parallel disposition of one relative to the other;

engagement means for keeping said teeth intermeshed at all positions of said scissors arms and for relieving stress on said hinged connections of said first and second channel-shaped members;

said scissors arms hingedly connected within said first and second channel-shaped members by oppositely positioned pairs of individual pin means, each engaging one side of the hingedly connected scissors arms; and

said engagement means including straps secured between opposite ones of each pair of pin means in said first and second channel-shaped members.

2. A scissors jack as claimed in claim 1 wherein said protection means include:

said channel-shaped scissors arms are of a depth substantially to enclose said threaded rod within said channels when said scissors arms are closed to the maximum extent.

3. A scissors jack as claimed in claim 1 wherein said first and second channel-shaped members include:

four relief slots aligned opposite the toothed ends of the channel-shaped scissors arms to allow said scissors arms to be opened to the maximum extent with said teeth extending into said slots.

4. In combination with a vehicle, at least one scissors jack mounted to the bottom of the vehicle frame, said scissors jack comprising:

a baseplate including a first channel-shaped member secured to said plate with the channel thereof opening upwardly of said plate;

means mounted to said bottom of said vehicle, including a second channel-shaped member mounted transversely of said vehicle and aligned substantially parallel with said first channel-shaped member and having its channel opening downwardly towards the baseplate, said mounting means including a third and a fourth channel-shaped member having their channels opening downwardly and secured to opposite sides of said second channel-shaped member, aligned with one another substantially normal to said second channel-shaped member and mounted to the bottom of said vehicle frame;

opposed pairs of channel-shaped scissors arms vertically aligned with said channel-shaped members and each pair of said arms being hingedly secured together at one end thereof to form a pivot point, the ends of each pair opposite its pivot point having teeth formed therein, the teeth of the upper arms being intermeshed and the upper arms being hingedly connected to said second channel-shaped member and having their channels opening downwardly, the teeth of the lower arms being intermeshed and the lower arms being hingedly connected to said first channel-shaped member and having their channels opening upwardly, the toothed ends of the upper arms being disposed for pivotal movement within the channel of the second channel-shaped member and the toothed ends of the lower arms being disposed for pivotal movement within the channel of the first channel-shaped member.

a bushing mounted for limited swinging movement at one pivot point and a nut mounted for limited swinging movement at the other pivot point;

a threaded rod extending between the pivot points and journaled in the bushing for free rotation therein while threadedly engaging in the nut;

means for rotating the rod;

means for preventing axial movement of the rod relative to the bushing, the length of the rod being greater than the distance between pivot points when the scissors arms are closed to their maximum extent;

means for protecting said threaded rod when said scissors arms are closed to their maximum extent;

rotation of the rod serving to open or close the scissors arms whereby to vary the vertical spacing between the first and second channel-shaped members without changing the parallel disposition of one relative to the other;

engagement means for keeping said teeth intermeshed at all positions of said scissors arms and for relieving stress on said hinged connections of said first and second channel-shaped members;

said scissors arms hingedly connected within said first and second channel-shaped members by oppositely positioned pairs of individual pin means, each engaging one side of the hingedly connected scissors arms; and

said engagement means including straps secured between opposite ones of each pair of pin means in said first and second channel-shaped members.

5. A scissors jack as claimed in claim 4 wherein said protection means include:

said channel-shaped scissors arms are of a depth substantially to enclose said threaded rod within said channels when said scissors arms are closed to the maximum extent.

6. A scissors jack as claimed in claim 4 wherein said first and second channel-shaped members include:

four relief slots aligned opposite the tooth ends of the channel-shaped scissors arms to allow said scissors arms to be opened to the maximum extent with said teeth extending into said slots.

7. A scissors jack including,

a baseplate including a first channel-shaped member secured to said plate with the channel thereof opening upwardly of said plate;

means adapted to be mounted permanently to the bottom of a vehicle including a second channel-shaped member aligned substantially parallel with said first channel-shaped member and having its channel opening downwardly towards the baseplate;

opposed pairs of channel-shaped scissors arms vertically aligned with said channel-shaped members and each pair of said arms being hingedly secured together at one end thereof to form a pivot point, the ends of each pair opposite its pivot point having teeth formed therein, the teeth of the upper arms being intermeshed and the upper arms being hingedly connected to said second channel-shaped member and having their channels opening downwardly, the teeth of the lower arms being intermeshed and the lower arms being hingedly connected to said first channel-shaped member;

a bushing mounted for limited swinging movement at one pivot point and a nut mounted for limited swinging movement at the other pivot point;

a threaded rod extending between the pivot points and journaled in the bushing for free rotation therein while threadedly engaging in the nut;

means for rotating the rod;

means for preventing axial movement of the rod relative to the bushing, the length of the rod being greater than the distance between pivot points when the scissors arms are closed to their maximum extent;

rotation of the rod serving to open or close the scissors arms whereby to vary the vertical spacing between the first and second channel-shaped members without changing the parallel disposition of one relative to the other;

the improvement comprising;

means for protecting said threaded rod when said scissors arms are closed to their maximum extent;

engagement means for keeping said teeth intermeshed at all positions of said scissors arms and for relieving stress on said hinged connections of said first and second channel-shaped members;

said scissors arms hingedly connected within said first and second channel-shaped members by oppositely positioned pairs of individual pin means, each engaging one side of the hingedly connected scissors arms;

said engagement means including straps secured between opposite ones of each pair of pin means in said first and second channel-shaped members; and

said mounting means including a third and a fourth channel-shaped member having their channels opening downwardly, secured to opposite sides of said second channel-shaped member and aligned with one another substantially normal to said second channel-shaped member.

8. A scissors jack as claimed in claim 7 wherein said first and second channel-shaped members include:

four relief slots aligned opposite the toothed ends of the channel-shaped scissors arms to allow said scissors arms to be opened to the maximum extent with said teeth extending into said slots.

9. A scissors jack as claimed in claim 7 wherein said protection means include:

said channel-shaped scissors arms are of a depth substantially to enclose said threaded rod within said channels when said scissors arms are closed to the maximum extent.