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Elevator Jacks

D.L. Martin manufactures rugged, reliable elevator components for global customers.  Structural components, in-ground hydraulic jacks, holeless hydraulic jacks, and roped hydraulic jacks have been a mainstay of the business. An engineering staff equipped with the latest Solidworks 3-D design software is available to assist customers to exceed their needs.

Unique capabilities include recognized global excellence in engineering of variable dimension and custom product lines using programmed Driveworks solutions.

All D. L. Martin jacks are designed and manufactured according to ASME A17.1-2013 requirements. The company is ISO 9001:2008 certified.  D.L. Martin is also approved by the Canadian Welding Bureau to CSA standard W47.1 Division 3 with AWS certified welders and standards. A zero defect AQL (acceptable quality level) 1.5 inspection program is used to assure the highest quality standards attainable are maintained throughout the manufacturing and assembly processes. 

A range of hydraulic jack plunger diameters from 2.95'' to 8'' in a variety of wall thicknesses are available to meet most requirements. Single stage or pre/assembled units can be supplied up to the maximum shipping length. Specialized centerless grinding equipment enables a cost effective solution to maximize throughput.

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Additional Information

Customer Satisfaction Survey
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Roped and Holeless Installation
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Holeless and roped jacks can be manufactured as a single piece or in multiple sections. A multi-piece jack has cylinder and plunger sections that couple together using threaded couplings and an o-ring seal. This joint design eliminates the time and expense of field welding the sections together. Below on the right is a sectional view of a two section holeless or roped jack. On the left is a similar section of a bottom inlet roped jack. The internal arrangement is the same except the centering pin has been removed and replaced with four guides spaced around the sides of the barrel as shown.
Roped and Holeless Jack Brochure
Roped and Holeless Jack Quote/Order Worksheet
Roped and Holeless Jack RFQ
Holeless and Roped Jack Ordering Guide
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Inground, Ropes, and Holeless Jack Seal Replacement
Seal Replacement
Borehole Jack Installation Instructions
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Borehole jacks are placed in a hole drilled into the ground to a depth roughly equal to the elevator car travel. Mounting feet welded to the cylinder sides are used to mount the jack to the pit floor. The mounting feet and oil inlet are designed not to interfere with each other, allowing freedom to vary their location to meet customer needs for various pit designs and depths. The jacks can be manufactured as a single piece or in multiple sections. A multi-piece jack has cylinder and plunger sections that couple together using threaded couplings and an o-ring seal. This joint design eliminates the time and expense of field welding the sections together. Below are sectional views of a typical two-section jack with an optional sealed PVC casing.
Inground Jack Brochure
In-Ground Jack Quote/Order Worksheet
Inground Jack RFQ

Frequently Asked Questions

Problem: Jack "bumps" when joints pass through head.

  • Possible Cause: Most likely cause is a tight wear band.
  • Solution: Request that D.L.M. send a new wear band with thickness at low limits.
  • Possible Cause: Joint blended too abrupt (can be checked with micrometers, or a straight edge and feeler guages-record results)
  • Solution: A wear band with thickness at the low limit may help. A joint with too abrupt a blend can be corrected by filing. Filing must not remove material away from the joint.
  • Possible Cause: Load ring for seal may be pinched, due to running upside down.
  • Solution: Check seal to make sure load ring is installed correctly. The tapered end of the ring should rest against the chamber of the actual seal.
  • Possible Cause: Joint blended too deep. If this is the case, slight leakage may be noticed as joint passes through head. (Can be checked with micrometers, or a straight edge and feeler gauges-record results)
  • Solution: New Plunger sections may be needed if problem is severe.
  • Possible Cause: Joint not blended in field. (If fingernail catches on joint, additional sanding is needed.)
  • Solution: Sand joint smooth with supplied sandpaper.

    • Problem: Ride is rough (not just at the joints)

  • Possible Cause: Jack not plumb. (Jack must be plumbed using plumb wire supplied in plunger sections.)
  • Solution: Re-plumb using plumb wire.
  • Possible Cause: Load ring for seal may be pinched, due to running upside down.
  • Solution: Check seal to make sure load ring is installed correctly. The tapered end of the ring should rest against the chamber of the actual seal.
  • Possible Cause: Tight wear band
  • Solution: Request that D.L.M. send a new wear band with thickness at low limit.

    • Problem: Jack squeals

  • Possible Cause: Tight wear band
  • Solution: Request that D.L.M. send a new wear band with thickness at low limit. A low friction oil additive could also be tried. Schindler spec. 54605ME

    • Problem: Scribe lines at plunger joint do not line up.

  • Possible Cause: Joint may have seized just before being fully tightened.
  • Solution: Lines should come within 1/8" of meeting up. If lines are past meeting up, do not back off joint (this may cause joint to loosen and come apart).
  • Possible Cause: Damaged thread on plunger coupling
  • Solution: Dress threads using thread file designed for 8-pitch UNC thread. Tool TD338 available.

    • Problem: Plunger scored vertically

  • Possible Cause: Plunger not plumb in cylinder, causing plunger to bind in the head.
  • Solution: Make sure both cylinder and plunger are plumb (at least aligned with each other).
  • Possible Cause: Chip or other debris caught in head
  • Solution: Remove head, check oil for contamination (use pump and filter if necessary as well as magnet to fish for chips). Chips may come from field installed hatch pipe and fittings, always clean pipe thoroughly before installing.
  • Possible Cause: Wear band too thin (correct thickness is .124"/. 127")
  • Solution: Replace wear band
  • Possible Cause: Wear band too thin (correct thickness is .124"/. 127")
  • Solution: Replace wear band
  • Possible Cause: Plunger joint was run through head prior to field blending.
  • Solution: Always blend joint before running jack.
  • Possible Cause: Plunger joint was run through head prior to field blending.
  • Solution: If damage is not severe, plunger may be repaired by smoothing with sandpaper, if scoring is deep, new plunger section(s) will be needed, as well as a new sleeve and seal kit.

    • Problem: Jack is too long.

  • Possible Cause: Ordering error
  • Solution: Order a stop sleeve to reduce overtravel.

    • Problem: Jack is too short.

  • Possible Cause: Ordering error
  • Solution: First, check to see if a plunger extension would solve the problem. (Need to be sure over- travel and undertravel would still be sufficient.) If extension won't work, then either a new jack section (for multi-pc) or a new jack (for a one-pc) must be ordered.

    • Problem: Banging noise (always occuring at same point in travel every trip)

  • Possible Cause: Plunger plug hitting cylinder joint.
  • Solution: Rotate plunger to locate "flat spot" on plunger plug next to cylinder wall.
  • Possible Cause: Plunger plug hitting cylinder joint.
  • Solution: Make sure plunger and cylinder are both plumb, and in alignment with each other.

    • Problem: Cylinder coupling can not be removed from jack shipping ass'y.

  • Possible Cause: Threads seized
  • Solution: Cut coupling off. Request new coupling from D.L.M.

    • Problem: Cylinder coupling doesn't turn freely when assembling sections.

  • Possible Cause: Split ring sections may not have proper curvature.
  • Solution: Slide coupling away from joint, and test fit split ring sections against the cylinder wall (in their normal location) if the split ring does not fit snugly along its entire length, its shape may be corrected by tapping with a mallet.
  • Possible Cause: Split ring sections may not have proper curvature.
  • Solution: If the condition is too severe to be corrected in the field, request D.L.M. to send a new pair of split ring halves.
  • Possible Cause: Damaged thread
  • Solution: If coupling can be backed off, do so, and repair thread with a thread file. Also inspect for debris which may be contributing to the problem.
  • Possible Cause: Damaged thread
  • Solution: If coupling seized up when partially engaged, it should be cut apart to remove. in this case, request D.L.M. to send a new coupling.

    • Problem: Unsure if cylinder joint is correctly assembled (completely together)

  • Possible Cause: Possible incorrect assembly
  • Solution: See orange warning label near cylinder joint - gap between male and female couplings should be about 1/8" and wide yellow painted line segments should line up within 1/2" when fully tightened.

    • Problem: Mounting feet in wrong location.

  • Possible Cause: Jack ordered for incorrect pit depth.
  • Solution: If feet are located to high on cylinder, an additional set can be welded on in the field by a certified welder. In this case order new feet and gussets from D.L.M.
  • Possible Cause: Jack ordered for incorrect pit depth.
  • Solution: If the current feet are in a location which would prevent new feet from being welded on correctly, the field may choose to use a spacer block between the footer channel and the feet.
  • Possible Cause: Jack ordered for incorrect pit depth.
  • Solution: If the feet are too low on the cylinder, they will need to be removed by grinding, before welding new feet on.

    • Problem: Unsure how stop ring is installed on plunger.

  • Possible Cause: Possible stop ring installation error.
  • Solution: The purpose of the stop ring is to limit current travel. typically it is to be located at the lowest plunger joint, and is sometimes used together with a stop sleeve which further limits travel.
  • Possible Cause: Possible stop ring installation error.
  • Solution: After determining which joint the stop ring should be placed at, slip the ring over the male coupling at that joint so that the 15 ° bevel on the underside of the ring matches the 15 ° bevel on the plunger.
  • Possible Cause: Possible stop ring installation error.
  • Solution: The mating plunger section can be lowered into position and assembled with the stop ring sandwiched between the two sections.

    • Problem: Difficulties assembling the 300A plunger joint.

  • Possible Cause: Nut installed incorrectly.
  • Solution: Check that the nut cannot be rotated in the female coupling. also check that the nut cannot be pushed up into the plunger more than about 1/16". Call 800 or 888 number stated on the jack if either of the two tests above indicate problems.

    • Problem: Vibrating noise in the car. Vibrating noise at leveling speed, up or down.

  • Possible Cause: 1. Leveling speed is too low. 2. Oil viscosity is too low. 3. Oil temperature is high. 4. Guide arms tight on the rails.
  • Solution: 1. Adjust. 2. Find means to reduce the temperature. 3. Add anti-chatter additive. exp max glide. make sure additive is safe for o-rings.

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      CNC Centerless Grinder

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